for very helpful discussions. Interest Rates and the Durability of Consumption Goods
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Why China’s_Economic_Reform_Differ：_the_M-Form_Hierarchy
The Economics of Transition, 1(2):135-170, June, 1993.Why China's Economic Reforms Differ:The M-Form Hierarchy and Entry/Expansion of the Non-State SectorbyYingyi Qian and Chenggang Xu1China's thirteen years of economic reforms (1979-1991) have achieved an average GNPannual growth rate of 8.6%. What makes China's reforms differ from those of EasternEurope and the Soviet Union is the sustained entry and expansion of the non-statesector. We argue that the organization structure of the economy matters. Unlike theirunitary hierarchical structure based on functional or specialization principles (the U-form), China's hierarchical economy has been the multi-layer-multi-regional one mainlybased on territorial principle (the deep M-form, or briefly, the M-form). Reforms havefurther decentralized the M-form economy along regional lines, which providedflexibility and opportunities for carrying out regional experiments, for the rise of non-state enterprises, and for the emergence of markets. This is why China's non-state sectorshare of industrial output increased from 22% in 1978 to 47% in 1991 and its privatesector's share from zero to about 10%, both being achieved without mass privatizationand changes in the political system.1. IntroductionRecently, there has been a revived interest among economists in China's economic reforms. Since 1979, economic reforms in China have generated a significant growth across the board: the overall performance of the Chinese economy has been better than its own past record, better than most developing countries at similar development levels, and also better than Eastern Europe and the former Soviet Union,1 Stanford University and London School of Economics, respectively. We would like to thank Philippe Aghion, Masahiko Aoki, Patrick Bolton, Avner Grief, Athar Hussain, Carla Krüger, Nicholas Lardy, John Litwack, Eric Maskin, John McMillan, Paul Milgrom, Dwight Perkins, Louis Putterman, Gerard Roland, Anna Seleny, Barry Weingast, Martin Weitzman, Jinglian Wu, and an anonymous referee for helpful discussions and comments. Qian's research is sponsored by the Center for Economic Policy Research (CEPR), the Hewlett Fund of the Institute of International Studies (IIS), and Center for East Asian Studies (CEAS) at Stanford University, and Xu's research is sponsored by the Center for Economic Performance (CEP) and the Suntory-Toyota International Center for Economics and Related Disciplines (STICERD) at London School of Economics.both before and after their radical transformations in 1989. It appears that China had no coherent reform programs, no commitment to private ownership, and no changes in the political system, and China's economy was still not fully liberalized. From both the theoretical and policy perspectives, China's different reform strategies and outstanding reform performances are particularly interesting and puzzling.The economic reforms in China formally started in 1979 following the Third Plenum of the Eleventh Congress of the Chinese Communist Party in December 1978. The starting time was later than that of Yugoslavia (1950) and Hungary (1968) and was about the same as for Poland (1980), and earlier than the Soviet Union (1986). Between 1979 and 1991, China's GNP grew at an average annual rate of 8.6%, or at 7.2% on the per capita basis.2 In 1992, the growth of GNP reached 12.8%.3 Exports grew at a faster pace, so that China's export-GNP ratio increased from below 5% in 1978 to nearly 20% in 1991.4 Also in this period, inflation was kept within a single-digit range except for three years (11.9% in 1985, 20.7% in 1988 and 16.3% in 1989); the household bank deposits to GNP ratio increased from 6% in 1978 to 46% in 1991; and the government budget deficit accounted for about 2-3% of GNP, about half of which was financed from bond issues (Table 1.1).Even more convincing evidence of the success of the reform is the increase in consumption and consumer durable goods by an average Chinese consumer in physical terms. For example, between 1978 and 1991, an average Chinese consumer increased his/her consumption about three times for edible vegetable oil, pork, and eggs (Table 1.2). In the rural areas, which account for about 75% of total population, the living space per person increased about 130% between 1978 and 1991 (Table 1.3). The2 Data sources in this paper are from Statistical Yearbook of China (various issues from 1985 to 1992), otherwise noted.3 Statistical Communique of the State Statistical Bureau on the 1992 National Economic and Social Development, February 18, 1992.4 The export-GNP ratios are calculated based on the official exchange rate and are upward biased. But the dramatic increase of export share in GNP during the reform is unmistaken.2average per household consumer durable goods, such as television sets, refrigerators and washing machines, also increased dramatically. For instance, in 1991, on average, every two rural households had one television set, and every urban household had more than one (Tables 1.4 and 1.5). There is no doubt that China is still a low-income developing country, but the evidence reveals clearly a substantial improvement in living standards due to economic reforms.The Chinese economic performance is in contrast to that of Eastern Europe and the former Soviet Union. Even if the two-digit annual decline of GNP in 1990 and 1991 in these countries was largely transitory, the magnitude was still too large to be ignored. What is more important, but tends to be neglected, is the economic stagnation in Eastern Europe and the Soviet Union in the decade of 1980s before the radical changes. According to official statistics, the average growth rate of GDP in Hungary was 1.8% between 1981 and 1985 and almost zero in 1988 and 1989. In Poland, the average GDP growth rate was less than 2% between 1981 and 1989.5 The situation in the Soviet Union was no better.Political considerations aside, two arguments often come into discussions on the differences between China and Eastern Europe. The first argument is about different levels of economic development: Eastern Europe and the Soviet Union were at a much higher development stage than China -- China had a very low per capita income with a dominant agriculture sector while the Eastern European and Soviet economies were "over-industrialized."6 The second argument is about different reform strategies: China has followed a gradual and piecemeal approach as opposed to the "big bang" strategy in most of after 1989 Eastern Europe and the former Soviet Union, like the shock therapy for stabilization in Poland and Russia,5 Data source for Hungary and Poland is from Table 9.1 of Kornai (1992).6 For example, Summers (1992) expressed this view when he highly praised China's reform performance. Sachs (1992) also expressed similar ideas during his interview with the Chinese Journal of Comparative Economic and Social Systems.3and fast and mass privatization in Czechoslovakia.7We feel that both views are relevant but unsatisfactory, or at least, are incomplete. China's level of industrialization was perhaps higher than most people would think. In 1978, China's gross industrial output value accounted for 62% of the total output value of society (35% in heavy industry and 27% in light industry), despite the fact that only 29% of the total labor force was employed in the non-agriculture sector. In terms of GNP, China's industry accounted for about half in 1978, as compared to 60% to 65% in Eastern Europe. Furthermore, in China, reforms have been more successful in the more industrialized regions with a weak central government control (like provinces of Guangdong, Jiangsu, and Zhejiang). Reforms have not been very successful in both the less industrialized regions (like the Northwest provinces) and the more industrialized regions with a strong central government control (like Shanghai and provinces of Liaoning and Jilin), the latter share similar problems of the earlier Hungarian reform. This fact suggests that one cannot explain the success of the reforms by low level of development alone.The argument for gradualism also raises more questions than answers. First, the agricultural reform in China proceeded very fast in the early 1980s. The abolishment of the commune system and the nationwide execution of the household responsibility system (an ownership reform) was implemented almost at one stroke, thus can be viewed as a big bang. More importantly, Eastern Europe's radical transition should not be examined in isolation: it came after deep troubles or failures of many years of gradual reform. In fact, the Hungarian reform started in 1968 with some initial success, but then ran into difficulties in the 1980s. Ironically, in several aspects China followed Eastern Europe's gradual reform measures. If China's gradualism is a success, why has it worked in China but not in Eastern Europe? On the other hand, why was China's success not a temporary one, and will China soon encounter problems similar to Hungary's?7 This view is reflected in Singh (1991), McMillan and Naughton (1992), and Chen, Jefferson and Singh (1992).4In this paper, we propose a theory to explain the differences between China's reforms and those of Eastern Europe and the Soviet Union. We first make an observation and provide extended evidence showing that, unlike the case of Eastern Europe and the Soviet Union, sustained entry and expansion of the non-state sector in China during the reforms were forceful and fast enough to become an important engine of growth by the end of the 1980s.8 We then theorize an institutional reason which is responsible for this phenomenal expansion and for the concurrent emergence of the market. We argue that the difference in the initial institutional conditions concerning the organizational structure of the planning hierarchy plays important roles in different transition paths of China and Eastern Europe and the former Soviet Union. The organization structures of both Eastern Europe and the Soviet Union were of a unitary form based on the functional or specialization principles (the "U-form" economy), and in contrast, the Chinese hierarchy has been of a multi-layer-multi-regional form mainly based on a territorial principle since 1958 (the "deep M-form" economy, or in short, the "M-form" economy). The M-form structure has been further decentralized along regional lines during reform with both increased authority and incentives for regional governments, which provided flexibility and opportunities for carrying out regional experiments, for the rise of non-state enterprises, and for the emergence of markets. Our institutional approach is able not only to incorporate and link together aspects of the arguments concerning the level of development and gradualism, but also to explain richer phenomena such as the successful use of experiments in China but not elsewhere.Under the M-form organization in China, interdependence between regional economies is not as strong as that of the U-form organization in Eastern Europe and the Soviet Union, because each region is relatively "self-contained." Unlike in Eastern Europe and the Soviet Union, regional governments in China (be it province, county, or township, village) have had considerable responsibility of coordination within the region. In particular, a large number of state-owned enterprises, including many in heavy industries, were8 We deliberately avoid the issue of the state sector. Evaluation of the reform in the state-sector has been controversial among China experts and Chinese economists.5subordinated under the regional governments even before the economic reforms. Hence, each region was relatively self-sufficient, the scale of an enterprise was small, and industries were less concentrated. In this environment, regional experiments can be carried out in a less costly way because the disruptive effect to the rest of the economy is minimal. A successful experiment in one region also has greater relevancy to other regions since adjacent regions are similar.When the M-form economy was further decentralized along regional lines in reform and the constraints on local government were gradually removed, the bottom level regional governments (i.e., townships and villages in the rural areas, and districts and neighborhoods in the urban areas) gained substantial autonomy in developing their own regions. They establish enterprises outside the state sector and outside the plan. From their inception, those non-state enterprises (most of them are not private though) have been market oriented. Furthermore, competition between regions for getting rich fast puts pressure on the local governments to concentrate on growth and their limited access to bank credits maintains discipline on their behavior. This explains how the rise of the non-state sector occurred by gradually weakening the existing hierarchical control without destroying the existing structure at one stroke.Of course, administrative decentralization induces, at the initial stage, costs of regional conflict, market protection, wasteful duplication, inefficient small scales of production and increased administrative intervention by local governments. We do not argue against these opinions but we would like to focus on a neglected but important aspect of benefits of a multi-layer-multi-regional form of organization, that is, the flexibility of the system for experiments and hence for institutional changes, and the opportunity provided to facilitate entry and expansion of the non-state sector outside the plan. The unexpected, and perhaps unintentional, growth of the non-state sector is critical for the success of China's economic reforms.Based on Chandler's seminal work (1966), Williamson (1975) first used the terms "U-form" and "M-form" in his study of business firms in the U.S. The U-form referred to the unitary organizational form6of the firm along functional lines in the second half of 1800s and early 1900s, while the M-form referred to the multi-divisional form of the firm organized by product, by technology, or by geography, which emerged since the 1920s. Compared with departments in the U-form firms, divisions in the multi-divisional firms are more self-contained, their responsibility for coordination and profit inside the division is high. The regional governments in our multi-layer-multi-regional structure economy share these features. However, our concept is not simply an application or an extension of the Chandler-Williamson's concept from firms to economies. There are important differences between the two concepts. In a multi-divisional firm, decentralization occurs exactly at the level of general office and the divisions, and each division is often organized by functions. In contrast, in our concept of the M-form economy, decentralization occurs at all levels of the hierarchy, that is, the M-form is deep. This is critically important: it is exactly because of the autonomy and incentives provided to the bottom levels of the regional governments in China, could the non-state sector grow so fast.The remaining part of the paper is organized as follows. Section 2 clarifies the definition of China's non-state sector and private sector. Section 3 provides empirical evidence on the sustained entry and expansion of the non-state sector between 1979 and 1991. Section 4 first characterizes institutions of the U-form hierarchies of Eastern Europe and the Soviet Union and the M-form hierarchy of China before the reform, and then describes several Chinese reform policies that are responsible for further decentralization along regional lines. Section 5 makes a general and preliminary analysis on the costs and benefits of the M-form organization vis-a-vis the U-form and the implications for transition. Section 6 explains specifically how the phenomenal expansion of the non-state sector in China is made possible under its M-form hierarchical organization. The final concluding section discusses implications of the non-state sector for further reforms in China and lessons from the Chinese experience for other economies in transition.72. What Is the Non-State Sector in China?92.1. The Non-State SectorBefore defining the non-state sector, we should first define the state sector. In China, by the constitution, the state-owned enterprises are owned by the "whole people." In practice, every state-owned enterprise is affiliated with one of the following four levels of government: (1) central; (2) provincial (with a population size of dozens of millions); (3) prefecture (with a population size of several millions); and (4) county (with a population size of several hundreds of thousands). A municipality is treated as one of the levels of province, prefecture or county, with a majority being at the level of a prefecture. Typically, the responsible government delegates the supervision of "its" state-owned enterprises to the industrial ministries/bureaus. Therefore, even for the state-owned enterprises, they are not homogeneous in terms of control.The non-state sector consists of all enterprises not in the state-sector, and it includes the private sector as a sub-sector. According to the location of its supervising government (if it has one), a non-state enterprise is designated as either an urban enterprise or a rural enterprise.10 By 1991, there were three categories of non-state ownership in China's official statistics: "collective ownership," "individual ownership," and "other types of ownership." Table 2.1 below provides a detailed picture with both official and alternative classifications:9 We only focus on the non-agriculture sector in this paper.10 An interesting and confusing fact is that many rural enterprises are located in urban areas. They are called "rural enterprises" simply because they are supervised by rural community governments (e.g. township or village governments) and the majority of their employees are not registered urban residents.8Table 2.1 China: Classification of the Non-State Sector(A) Collectives (jiti). Urban collectives include (i) enterprises that are affiliated with a district government under a municipality or a county ("large" collectives, dajiti); (ii) enterprises that are affiliated with a neighborhood under a district ("small" collectives, xiaojiti); and (iii) urban cooperatives (chengzhen hezuo). Many urban collectives are subsidiaries of state-owned enterprises which receive some transferred assets from the parent firms and hire their surplus employees or the employees' spouses and children. The advantages of subsidiaries being registered as collectives under the supervision of lower level government is less government control and more business flexibility.11Rural collectives include (i) enterprises that are affiliated with a township (xiang or zhen) government; (ii) enterprises that are affiliated with a village (cun) government; and (iii) rural cooperatives (nongcun hezuo). The predecessors of township and village enterprises (TVEs) were commune and brigade enterprises (CBEs) emerging during the Great Leap Forward in 1958. The ownership form of11 This is known as "one factory, two systems" (yichang liangzhi) in China, referring to the planned system for the state-owned part, and the market system for the collective part.9township and village enterprises is truly a Chinese invention that has not been found elsewhere.(B) Individual Business (geti). These are household/individual businesses hiring no more than 7 employees. An individual business has been allowed to operate since 1978.(C) Other Types of Ownership (qita leixing). This category includes mainly (i) private enterprises hiring more than 7 employees (siying); (ii) foreign enterprises and joint ventures with foreigners (sanzi qiye); and (iii) other types of joint ventures (e.g., a joint venture between state and private enterprises) and joint-stock companies. These types of ownership did not emerge until the early 1980s.122.2. The Private SectorDefining the non-state sector in China is easy, but defining the private sector is not. As seen above, a "private enterprise" is defined in China as a private business establishment hiring more than 7 employees. This narrow definition is on purpose, in order to circumvent ideological difficulties. For example, an individual/household hiring no more than 7 employees is classified as an "individual business," not as a "private enterprise," although it is certainly part of the private sector. So are sole foreign business establishments. As for joint ventures and joint-stock companies, strictly speaking, only those shares that are owned by foreigners and domestic private parties can be regarded as in the private sector.13 Some "cooperatives" are more like partnerships hiring many employees. This is especially true in Southern China, and in some areas they are called "joint stock cooperatives" (gufen hezuo). In addition, some township and village enterprises and urban district and neighborhood enterprises are de facto private12 If a state-owned enterprise is converted to a joint-stock company or limited liability company ("corporatization") or becomes a joint venture, it will be reclassified into the catagory of "others." As a result, it will not be regarded as "state-owned" anymore, despite the fact that the state may still own the majority interests. This may cause interpretation problems of the non-state sector in the future as more and more such a conversion occur starting in 1992.13 About one-half of "others" can be counted as truly private.10enterprises with vaguely defined ownership under the name of collectives.14Lacking further information and taking approximations, our definition of the private sector in China in this paper will include individual ownership, cooperative ownership, and other types of ownership under the official classification, and will exclude all of the township and village enterprises. We speculate that this should not give too much bias in either direction for data prior to 1992. The remaining part of the collectives, that is, enterprises affiliated with an urban district or neighborhood and with a rural township or village (TVEs), can be regarded as the community sector.3. Sustained Entry and Expansion of the Non-State Sector in China: Evidence3.1. General FeaturesFrom 1978 to 1991, the share of the non-state sector in national non-agriculture employment increased from about 40% to 57%. However, this happened not because of privatization or conversion of state enterprises to non-state enterprises. It is mainly due to entry and expansion of new non-state enterprises. In fact, employment by the state sector increased from 75 million in 1978 to 107 million in 1991. Its share declined because employment in the non-state sector grew even faster: from 21 million to 44 million in the urban area and from 28 million to 96 million in the rural during the same period.China's non-state sector is engaged in all kinds of activities: construction, transportation, commerce, service, and in particular, industry. This is perhaps a crucial difference between China's non-state sector and the private sector in Eastern Europe, particularly before 1989.15 During the period from14 For example, the famous computer company Stone Group is officially a "large collective" under Haidian district in the Beijing municipality, but actually run by a group of private businessmen. In Wenzhou municipality of the Zhejiang province, any business establishment with more than three co-owners is classified as a "collective," and is often called a "township" or "village" enterprise.15 See Kornai (1986) for the private sector development in Hungary before 1989.111981 to 1990, the national average annual growth rate of gross industrial output was 12.6%, in which the state sector grew at 7.7%, collectives at 18.7%, individual business at 92.2% and other types of ownership at 42.7%. As a result, the share of the non-state industry in the national total has expanded gradually from 22% in 1978 to 47% in 1991, and accordingly, the share of the state sector in industrial output shrunk from 78% to 53%. To put this into a historical perspective, the share of the state sector in 1991 is already below the level in 1957, which was 54% (Table 3.1).16The change of ownership composition of Chinese industry toward the non-state sector did not happen overnight. In fact, the process started before 1979. Although the true private industry in China did not appear until the early 1980s, the collectives had grown from 11% out of the national total in 1969 to 22% in 1978, or about one percent increase in output share every year (Table 3.1). However, the dramatic shift of weight toward the non-state sector has been apparent since 1979: The non-state sector in industry has on average experienced an increase in industrial share two percentage points every year for 13 years.17 Accompanied by the high growth rate, the non-state sector is also more efficient than the state sector. The annual growth rate of the total factor productivity of the non-state enterprises was much higher than that of the state enterprises.18 If one ranks all China's provinces according to their shares of the non-16 In 1957 the first five year plan was finished. At that time, there were still many state-private jointly-owned enterprises (gongsi heying). One year later, during the Great Leap Forward in 1958, the share of the state sector jumped to 90%.17 The Information Center of the State Planning Commission in China has already predicted that by the year 2000 only about one-quarter of industrial production will be produced by the state-sector in China. However, see footnote 11 for qualification to this statement.18 From 1982 to 1987, the annual growth rate of the total factor productivity of the TVEs is 12.5% at the national level, and 15% in the coastal areas (Xu, 1991). In contrast, from 1978 to 1985, the annual growth rate of the total factor productivity of the state-owned enterprises is 1.3% at the national level (Chen, et. al., 1988). Another piece of evidence comes from Xiao (1991). Using the provincial data from 1985 to 1987, Xiao shows a significant positive correlation between the total factor productivity of the provincial economies and the non-state sector share of the industrial output (with an exception of Shanghai).12state sector in industrial output, the top five, Zhejiang, Jiangsu, Guangdong, Shandong and Fujian, are precisely those provinces that have much higher growth than the national average.19 An interesting counter example of the coastal region is Shanghai. Shanghai was one of the most important financial and industrial centers in the Far East before 1949 and was also the industrial base after 1949. Shanghai has a low share of the non-state sector in industry as compared to the national average: 22% in 1985 and 32% in 1990. For the period from 1984 to 1989, Shanghai's industry grew only 7.9%, well below the national average. Shanghai's share of industrial output dropped from 10% in 1985 to only 6.8% in 1989, below that of Jiangsu, Shandong or Guangdong.Three additional characteristics about the entry and expansion of the non-state sector in China should be especially emphasized. First, the substantial entry and expansion occurred not because of an intentional design of a reform program from the central government, to the contrary, it came largely from the local initiatives. The central government's tolerance is mainly because it solves unemployment problems without much financial support from the state. Second, and related to the first, there has been a large variance in terms of organizational and developmental patterns of non-state-owned enterprises across regions. For example, while export and foreign investment have played important roles in some parts of Guangdong and Fujian, they are not so vital in many other high-growth provinces. On the other hand, township and village enterprises are a dominant force of the non-state sector in Jiangsu and Shandong, but individual, partnership and private enterprises are much more important in Zhejiang.Third, by 1991, the collectives and joint-ventures are the dominant majority of the non-state sector, and privately-owned enterprises played a minor role on the national scale. The collectives and joint-ventures have larger scale of operation, employ better technology, and absorb more human capital. This is because in China, there is still a lack of legal protection of private property rights, let alone commitment to19 These five provinces are all the coastal provinces. Because of the rapid growth, the share of industrial output of these five provinces in the national total rose from 30% in 1985 to 37% in 1990.13。
英语活动类作文带翻译
The English speech contest is a good opportunity to exercise oral expression and self-confidence. For example, the school organizes a themed speech contest, and students can choose topics of interest to express themselves orally. Not only can they improve their English speaking skills, but they can also exercise their thinking abilities and build self-confidence.
2. English Play Performance
Performing English plays is a good way to improve English speaking skills. By playing different characters, students can better understand and use English while also cultivating their teamwork and performance abilities.
范例：校园里最受欢迎的活动之一就是每周五下午的英语沙龙交流会，我们会在一起谈论英语电影、英语歌曲，还会进行一些英语游戏，不知不觉中就提高了自己的英语水平，也交到了很多朋友。
总的来说，参加各种形式的英语活动可以让学生们在轻松愉快的氛围中提高英语水平，培养兴趣，更好地理解和运用英语。希望同学们能积极参与，多多运用英语，不断提升自己的语言能力。
The Twin Crises The Causes of Banking and Balance-of-Payments Problems
Forthcoming in American Economic ReviewFirst Draft: December 1995This Version: November 9, 1998The Twin Crises: The Causes of Banking andBalance-of-Payments ProblemsGraciela L. Kaminsky Carmen M. Reinhart*AbstractIn the wake of the Mexican and Asian currency turmoil, the subject of financial crises has come to the forefront of academic and policy discussions. This paper analyzes the links between banking and currency crises. We find that: problems in the banking sector typically precede a currency crisis--the currency crisis deepens the banking crisis, activating a vicious spiral; financial liberalization often precedes banking crises. The anatomy of these episodes suggests that crises occur as the economy enters a recession, following a prolonged boom in economic activity that was fueled by credit, capital inflows and accompanied by an overvalued currency. (JEL F30, F41)* Graciela L. Kaminsky, George Washington University, Washington, D.C. 20552. Carmen M. Reinhart, University of Maryland, College Park, Maryland 20742. We thank two anonymous referees for very helpful suggestions. We also thank Guillermo Calvo, Rudiger Dornbusch, Peter Montiel, Vincent Reinhart, John Rogers, Andrew Rose and seminar participants at Banco de México, the Board of Governors of the Federal Reserve System, Florida State University, Harvard, the IMF, Johns Hopkins University, Massachusetts Institute of Technology, Stanford University, SUNY at Albany, University of California, Berkeley, UCLA, University of California, Santa Cruz, University of Maryland, University of Washington, The World Bank, and the conference on “Speculative Attacks in the Era of the Global Economy: Theory, Evidence, and Policy Implications,” (Washington, DC, December 1995), for very helpful comments and Greg Belzer, Kris Dickson, and Noah Williams for superb research assistance.Pervasive currency turmoil, particularly in Latin America in the late 1970s and early 1980s, gave impetus to a flourishing literature on balance-of-payments crises. As stressed in Paul Krugman’s (1979) seminal paper, in this literature crises occur because a country finances its fiscal deficit by printing money to the extent that excessive credit growth leads to the eventual collapse of the fixed exchange rate regime. With calmer currency markets in the mid- and late 1980s, interest in this literature languished. The collapse of the European Exchange Rate Mechanism, the Mexican peso crisis, and the wave of currency crises sweeping through Asia have, however, rekindled interest in the topic. Yet, the focus of this recent literature has shifted. While the earlier literature emphasized the inconsistency between fiscal and monetary policies and the exchange rate commitment, the new one stresses self-fulfilling expectations and herding behavior in international capital markets.1 In this view, as Guillermo A.Calvo (1995, page 1) summarizes “If investors deem you unworthy, no funds will be forthcoming and, thus, unworthy you will be.”Whatever the causes of currency crises, neither the old literature nor the new models ofself-fulfilling crises have paid much attention to the interaction between banking and currency problems, despite the fact that many of the countries that have had currency crises have also had full-fledged domestic banking crises around the same time. Notable exceptions are: Carlos Diaz-Alejandro (1985), Andres Velasco (1987), Calvo (1995), Ilan Goldfajn and Rodrigo Valdés (1995), and Victoria Miller (1995). As to the empirical evidence on the potential links between what we dub the twin crises, the literature has been entirely silent. The Thai, Indonesian, and Korean crises are not the first examples of dual currency and banking woes, they are only the recent additions to a long list of casualties which includes Chile, Finland, Mexico, Norway, and Sweden.In this paper, we aim to fill this void in the literature and examine currency and banking crises episodes for a number of industrial and developing countries. The former include: Denmark, Finland, Norway, Spain, and Sweden. The latter focus on: Argentina, Bolivia, Brazil, Chile, Colombia, Indonesia,1Israel, Malaysia, Mexico, Peru, the Philippines, Thailand, Turkey, Uruguay, and Venezuela. The period covered spans the 1970s through 1995. This sample gives us the opportunity to study 76 currency crises and 26 banking crises. Out-of sample, we examine the twin crises in Asia of 1997.Charles Kindelberger (1978, page 14), in studying financial crises, observes: “For historians each event is unique. Economics, however, maintains that forces in society and nature behave in repetitive ways. History is particular; economics is general.” Like Kindelberger, we are interested in finding the underlying common patterns associated with financial crises. To study the nature of crises, we construct a chronology of events in the banking and external sectors. From this timetable, we draw inference about the possible causal patterns among banking and balance-of-payments problems and financial liberalization. We also examine the behavior of macroeconomic indicators that have been stressed in the theoretical literature around crisis periods, much along the lines of Barry Eichengreen et. al. (1996a). Our aim is to gauge whether the two crises share a common macroeconomic background. This methodology also allows us to assess the fragility of economies around the time of the financial crises and sheds light on the extent to which the crises were predictable. Our main results can be summarized as follows:First, with regard to the linkages among the crises, our analysis shows no apparent link between balance of payments and banking crises during the 1970s, when financial markets were highly regulated. In the 1980s, following the liberalization of financial markets across many parts of the world, banking and currency crises become closely entwined. Most often, the beginning of banking sector problems predate the balance of payment crisis; indeed, knowing that a banking crisis was underway helps predict a future currency crisis. The causal link, nevertheless, is not unidirectional. Our results show that the collapse of the currency deepens the banking crisis, activating a vicious spiral. We find that the peak of the banking crisis most often comes after the currency crash, suggesting that existing problems were aggravated or new ones created by the high interest rates required to defend the exchange rate peg or the foreign exchange exposure of banks.2Second, while banking crises often precede balance of payments crises, they are not necessarily the immediate cause of currency crises, even in the cases where a frail banking sector puts the nail in the coffin of what was already a defunct fixed exchange rate system. Our results point to common causes, and whether the currency or banking problems surface first is a matter of circumstance. Both crises are preceded by recessions or, at least, below normal economic growth, in part attributed to a worsening of the terms of trade, an overvalued exchange rate, and the rising cost of credit; exports are particularly hard hit. In both types of crises, a shock to financial institutions (possibly financial liberalization and/or increased access to international capital markets) fuels the boom phase of the cycle by providing access to financing. The financial vulnerability of the economy increases as the unbacked liabilities of the banking system climb to lofty levels.Third, our results show that crises (external or domestic) are typically preceded by a multitude of weak and deteriorating economic fundamentals. While speculative attacks can and do occur as market sentiment shifts and, possibly, herding behavior takes over (crises tend to be bunched together), the incidence of crises where the economic fundamentals were sound are rare.Fourth, when we compared the episodes in which currency and banking crises occurred jointly to those in which the currency or banking crisis occurred in isolation, we find that for the twin crises, economic fundamentals tended to be worse, the economies were considerably more frail, and the crises (both banking and currency) were far more severe.The rest of the paper is organized as follows. The next section provides a chronology of the crises and their links. Section II reviews the stylized facts around the periods surrounding the crises while Section III addresses the issues of the vulnerability of economies around the time of the crisis and the issue of predictability. The final section discusses the findings and possibilities for future research.I. The Links Between Banking and Currency CrisesThis section briefly discusses what the theoretical literature offers as explanations of the possible3links between the two crises. The theoretical models also guide our choice of the financial and economic indicators used in the analysis.A. The links: theoryA variety of theoretical models have been put forth to explain the linkages between currency and banking crises. One chain of causation, stressed in James Stoker (1995), runs from balance of payments problems to banking crisis. An initial external shock, such as an increase in foreign interest rates, coupled with a commitment to a fixed parity will result in the loss of reserves. If not sterilized, this will lead to a credit crunch, increased bankruptcies, and financial crisis. Moreover, Frederic Mishkin (1996) argues that, if a devaluation occurs, the position of banks could be weakened further if a large share of their liabilities is denominated in a foreign currency. Models, such as Velasco (1987), point to the opposite causal direction--financial sector problems give rise to the currency collapse. Such models stress that when central banks finance the bail-out of troubled financial institutions by printing money, we return to the classical story of a currency crash prompted by excessive money creation.A third family of models contend that currency and banking crises have common causes. An example of this may be found in the dynamics of an exchange rate-based inflation stabilization plan, such as that of Mexico in 1987. Theory and evidence suggest that such plans have well-defined dynamics: 2 Because inflation converges to international levels only gradually, there is a marked cumulative real exchange rate appreciation. Also, at the early stages of the plan there is a boom in imports and economic activity, financed by borrowing abroad. As the current account deficit continues to widen, financial markets become convinced that the stabilization program is unsustainable, fueling an attack against the domestic currency. Since the boom is usually financed by a surge in bank credit, as banks borrow abroad, when the capital inflows become outflows and asset markets crash, the banking system caves in. Ronald I. McKinnon and Huw Pill (1996) model how financial liberalization together with microeconomic distortions--such as implicit deposit insurance--can make these boom-bust cycles even more pronounced by4fueling the lending boom that leads to the eventual collapse of the banking system. Ilan Goldfajn and Rodrigo Valdés (1995) show how changes in international interest rates and capital inflows are amplified by the intermediating role of banks and how such swings may also produce an exaggerated business cycle that ends in bank runs and financial and currency crashes.So, while theory does not provide an unambiguous answer as to what the causal links between currency and banking crises are, the models are clear as to what economic indicators should provide insights about the underlying causes of the twin crises. High on that list are international reserves, a measure of excess money balances, domestic and foreign interest rates, and other external shocks, such as the terms of trade. The inflation stabilization-financial liberalization models also stress the boom-bust patterns in imports, output, capital flows, bank credit, and asset prices. Some of these models also highlight overvaluation of the currency, leading to the underperformance of exports. The possibility of bank runs suggests bank deposits as an indicator of impending crises. Finally, as in Krugman (1979) currency crises can be the byproduct of government budget deficits.B. The Links: Preliminary EvidenceTo examine these links empirically, we first need to identify the dates of currency and banking crises. In what follows, we begin by describing how our indices of financial crises are constructed. Definitions, dates, and incidence of crisesMost often, balance of payments crises are resolved through a devaluation of the domestic currency or the floatation of the exchange rate. But central banks can and, on occasion, do resort to contractionary monetary policy and foreign exchange market intervention to fight the speculative attack. In these latter cases, currency market turbulence will be reflected in steep increases in domestic interest rates and massive losses of foreign exchange reserves. Hence, an index of currency crises should capture these different manifestations of speculative attacks. In the spirit of Eichengreen, et. al. (1996 a and b), we constructed an index of currency market turbulence as a weighted average of exchange rate changes and reserve changes.35With regard to banking crises, our analysis stresses events. The main reason for following this approach has to do with the lack of high frequency data that capture when a financial crisis is underway. If the beginning of a banking crisis is marked by a bank runs and withdrawals, then changes in bank deposits could be used to date the crises. Often, the banking problems do not arise from the liability side, but from a protracted deterioration in asset quality, be it from a collapse in real estate prices or increased bankruptcies in the nonfinancial sector. In this case, changes in asset prices or a large increase in bankruptcies or nonperforming loans could be used to mark the onset of the crisis. For some of the earlier crises in emerging markets, however, stock market data is not available.4 Indicators of business failures and nonperforming loans are also usually available only at low frequencies, if at all; the latter are also made less informative by banks’ desire to hide their problems for as long as possible.Given these data limitations, we mark the beginning of a banking crisis by two types of events: (1) bank runs that lead to the closure, merging, or takeover by the public sector of one or more financial institutions (as in Venezuela 1993); and (2) if there are no runs, the closure, merging, takeover, orlarge-scale government assistance of an important financial institution (or group of institutions), that marks the start of a string of similar outcomes for other financial institutions (as in Thailand 1996-97). We rely on existing studies of banking crises and on the financial press; according to these studies the fragility of the banking sector was widespread during these periods. This approach to dating the beginning of the banking crises is not without drawbacks. It could date the crises too late, because the financial problems usually begin well before a bank is finally closed or merged; it could also date the crises too early, because the worst of crisis may come later. To address this issue we also date when the banking crisis hits its peak, defined as the period with the heaviest government intervention and/or bank closures.Our sample consists of 20 countries for the period 1970-mid-1995. The countries are those listed in the introduction and Appendix Tables 1 and 2. We selected countries on the multiple criteria of being small open economies, with a fixed exchange rate, crawling peg, or band through portions of the sample;6data availability also guided our choices. This period encompasses 26 banking crises and 76 currency crises.As to the incidence of the crises (Table 1 and Figure 1), there are distinct patterns across decades. During the 1970s we observe a total of 26 currency crises, yet banking crises were rare during that period, with only 3 taking place. The absence of banking crises may reflect the highly regulated nature of financial markets during the bulk of the 1970s. By contrast, while the number of currency crises per year does not increase much during the 1980s and 1990s (from an average of 2.60 per annum to 3.13 per annum, Table 1, first row), the number of banking crises per year more than quadruples in the post-liberalization period. Thus, as the second row of Table 1 higlights, the twin crisis phenomenon is one of the 1980s and 1990s.Figure 1 also shows that financial crises were heavily bunched in the early 1980s, when real interest rates in the United States were at their highest level since the 1930s. This may suggest that, external factors, such as interest rates in the United States, matter a great deal as argued in Calvo, et. al. (1993). Indeed, Jeffrey Frankel and Andrew K. Rose (1996) find that foreign interest rates play a significant role in predicting currency crashes. A second explanation why crises are bunched is that contagion effects may be present, creating a domino effect among those countries that have anything less than immaculate fundamentals. Sara Calvo and Reinhart (1996) present evidence of contagion in capital flows to Latin American countries while Eichengreen, et. al.(1996b) find evidence that knowing there is a crisis elsewhere increases the probability of a domestic currency crisis.Table 2 provides the dates of financial liberalization, the beginning and peak of the banking crisis, and the date of the balance of payments crisis that was nearest to the beginning of the banking crisis.5 By selecting the nearest currency crisis, whether it predates or follows the beginning of the banking crisis, we allow the data to reveal what the temporal patterns are. The dates for the remaining crises are given in the Appendix tables.The twin crises7We next examine how the currency and banking crises are linked. We begin by calculating the unconditional probability of currency crises and banking crises in our sample. For instance, the probability that a currency crisis will occur in the next 24 months over the entire sample is simply 24 times 76 (the total number of currency crises in the sample) divided by the total number of monthly observations in the sample. These calculations yield unconditional probabilities for currency and banking crises, which are twenty nine percent and ten percent, respectively (Table 3). The difference in the probabilities of the two kinds of crises highlights the relatively higher frequency of currency crises in the sample.We next calculate a family of conditional probabilities. For instance, if knowing that there is a banking crisis within the past 24 months helps predict a currency crisis then, the probability of a currency crisis, conditioned on information that a banking crisis is underway, should be higher than the unconditional probability of a balance of payments crisis. In other words, a banking crisis increases the probability that a country will fall prey to a currency crisis. This is precisely what the results summarized in Table 3 show. The probability of a currency crisis conditioned on the beginning of banking sector problems is 46 percent, well above the unconditional estimate 29 percent. Hence, it could be argued, as Diaz Alejandro (1985) and Velasco (1987) did for the Chilean crisis in the early 1980s, that, in an important number of cases, the bail-out of the banking system may have contributed to the acceleration in credit creation observed prior to the currency crises (see Herminio Blanco and Peter M. Garber (1986), Sebastian Edwards (1989), and Eichengreen et. al. (1996a), and this paper). Even in the absence of a large-scale bail-out, a frail banking system is likely to tie the hands of the central bank in defending the currency--witness Indonesia in August 1997.If, instead, the peak of the banking crisis is used as the conditioning piece of information, no valuable information is gained; indeed, the conditional probability is 22 percent and below the unconditional. This result follows from the fact that a more common pattern (see Table 2) appears to be that the peak of the banking crisis comes after the currency crisis. For instance, knowing that there is a8currency crisis does not help predict the onset of a banking crisis, this conditional probability is 8 percent; knowing that there was a currency crisis does help to predict the probability that the banking crisis will worsen, this conditonal probability is 16 percent.Taken together, these results seem to point to the existence vicious circles. Financial sector problems undermine the currency. Devaluations, in turn, aggravate the existing banking sector problems and create new ones. These adverse feedback mechanisms are in line with those suggested by Mishkin (1996) and can be amplified, as we have seen in several of the recent Asian crises, by banks’ inadequate hedging of foreign exchange risk. The presence of vicious circles would imply that, a priori, the twin crises are more severe than currency or banking crises that occur in isolation.To measure the severity of a currency crisis, we focus on a composite measure that averages reserve losses and the real exchange rate depreciation.6 For reserves, we use the six-month percent change prior to the crisis month, as reserve losses typically occur prior to the devaluation (if the attack is successful). For the real exchange rate, we use the six-month percent change following the crisis month, because large depreciations occur after, and only if, the central bank concedes by devaluing or floating the currency. This measure of severity is constructed for each currency crisis in our sample and the averages are reported in Table 4 separately for the 19 twin crises in our sample and for the others. In line with our results that the beginning of the banking crisis precedes the balance of payments crisis, we define the twin crises as those episodes in which a currency crisis follows the beginning of the banking crisis within the next 48 months. For banking crises, we use the bail-out costs, as a percent of GDP, as the measure of severity. As Table 4 highlights, bail-out costs are significantly larger (more than double) in the twin crises than for banking crises which were not accompanied by a currency crisis. As to balance of payments crises, the results are mixed. Reserve losses sustained by the central bank are significantly bigger (Table 4) but the real depreciations are of comparable orders of magnitude.Our results also yield an insight as to the links of crises with financial liberalization (Table 3). In918 of the 26 banking crises studied here, the financial sector had been liberalized during the preceding five years, usually less. Only in a few cases in our sample countries, such as the early liberalization efforts of Brazil in 1975 and Mexico in 1974, was the liberalization not followed by financial sector stress. In the 1980s and 1990s most liberalization episodes have been associated with financial crises of varying severity. Only in a handful of countries (for instance, Canada which is not in the sample) did financial sector liberalization proceed smoothly. Indeed, the probability of a banking crisis (beginning) conditional on financial liberalization having taken place is higher than the unconditional probability of a banking crisis. This suggests that the twin crises may have common origins in the deregulation of the financial system and the boom-bust cycles and asset bubbles that, all too often, accompany financial liberalization. The stylized evidence presented in Gerald Caprio and Daniela Klingebiel (1996) suggests that inadequate regulation and lack of supervision at the time of the liberalization may play a key role in explaining why deregulation and banking crises are so closely entwined.II. The Macroeconomic Background of the CrisesTo shed light on whether both types of crises may have common roots, we analyze the evolution of 16 macroeconomic and financial variables around the time of the crises. The variables used in the analysis were chosen in light of theoretical considerations and subject to data availability. Monthly data was usedto get a clearer view (than would otherwise be revealed by lower frequency data) of developments as the crisis approaches and by the desire to evaluate to what extent these indicators were giving an early signal of impending trouble--an issue that will be taken up in the next section.The indicators associated with financial liberalization are the M2 multiplier, the ratio of domestic credit to nominal GDP, the real interest rate on deposits, and the ratio of lending-to-deposit interest rates. Other financial indicators include: excess real M1 balances, real commercial bank deposits, and the ratioof M2 (converted into U.S. dollars) divided by foreign exchange reserves (in U.S. dollars).7 The indicators linked to the current account include the percent deviation of the real exchange rate from trend, as a10measure of misalignment, the value of exports and imports (in U.S. dollars), and the terms-of-trade.8 The indicators associated with the capital account are: foreign exchange reserves (in U.S. dollars) and the domestic-foreign real interest rate differential on deposits (monthly rates in percentage points). The indicators of the real sector are industrial production and an index of equity prices (in U.S. dollars). 9 Lastly, the fiscal variable is the overall budget deficit as a percent of GDP.Of course, this is not an exhaustive list of potential indicators. In particular, political variables, such as the timing of an election, can also be linked to the timing of these crises. Indeed, the evidence presented in Deepak Mishra (1997), who examines a subset of the currency crises in this study, suggests that devaluations, more often than not, follow elections. Indeed, an election raises the probability of a future devaluation, even after controlling for economic fundamentals.Except for the interest rate variables, the deviations of the real exchange rate from trend, our proxy for excess real M1 balances, and the lending/deposit interest rates ratio, which are in levels, we focus on the 12-month percent changes of the remaining 10 variables. The pre- and post-crises behavior of all variables is compared to the average behavior during tranquil periods, which are all the remaining observations in our sample and serves as our control group.Figures 2, 3, and 4 illustrate the behavior of the variables around the time of the balance of payments, banking crises, and twin crises, respectively; each panel portrays a different variable. The horizontal axis records the number of months before and after the beginning of the crises; the vertical axis records the percent difference (percentage point difference for interest rates) between tranquil and crisis periods. In all the figures the solid line represents the average for all the crises for which data was available.10 Hence, if no data points are missing, the solid line represents the average behavior of that indicator during the months around 76 currency crises and 26 banking crises. For Figures 2 and 3, the dotted lines denote plus/minus one standard error around the average. For example, the top center panel of Figure 2 shows that, on average, the 12-month growth in the domestic credit/GDP ratio is about 15 percent11higher than in tranquil times. In Figure 4 the solid line shows the evolution of the indicators for the twin crises episodes while the dashed line denotes the averages for the currency crises that were not accompanied by a banking crisis.For currency crises we focus on the 18-month period before and after the crisis. Unlike balance of payments crises, in which reserves are lost abruptly and currency pegs abandoned, banking crises are protracted affairs which tend to come in waves and, hence, the depth of the crisis is seldom reached at the first sign of outbreak (see Table 2). For this reason, we widen the window and focus on the 18 months before the onset of the crisis, a 18-month arbitrarily chosen crisis period, and the 18 months post-crisis period. At any rate, because most of our analysis focuses on the causes leading up to the crises, our main results will not be affected whether the crises lasted less or more than a year. For the 19 episodes of the twin crises, we focus on the 18 months prior to the balance of payments crisis. Given that banking crises usually predate currency crises in our sample, this implies we are already looking at a period of heavy financial sector stress.A. The Financial SectorUntil the 1970s, most financial markets were regulated with rationed credit and, often, negative real interest rates. The late 1970s and beginning of the 1980s, however, witnessed sweeping financial reforms both in developed and emerging markets, which led to, among other things, increases in real interest rates. 11 Because financial liberalization often precedes banking crises--the indicators associated with financial liberalization presented in the first four panels of Figures 2, 3, and 4 (from left to right) merit scrutiny. The growth in the M2 multiplier rises steadily up to nine months prior to the currency crisis and the onset of the banking crisis; indeed, for banking crises the multiplier grows at above normal rate in the entire 18 months prior to the crisis. The draconian reductions in reserve requirements that often accompany financial liberalization play a role in explaining the large increases in the M2 multiplier. Yet the rise in the multiplier prior to currency crises is entirely accounted for by its evolution ahead of the twin12。
给国外客人的感谢信
给国外客人的感谢信dear ____________,please excuse my delay in thanking you for your hospitality during our visit to your firm on ____________ [date].i found our discussions very helpful and encouraging. we now have a better understanding of your needs and will soon submit another proposed contract for your approval. we expect to have it ready by ____________ [date].again, thank you for the pleasant visit.yours sincerely,____________ [name]____________ [ ]尊敬的__________，我们于__________[日期]拜访了贵公司，您的热情款待让我们十分感激，在此请您接受我们这份迟到的谢意。
我们的`讨论是十分有益且令人鼓舞的。
我们现已进一步了解了您的需求，并将很快向您呈上一份新的合同提议供您批阅，#url#预计该提议将于______[日期]前完成。
再次感谢您为我们安排的这次愉快的访问。
此致，__________[姓名]__________[头衔]s(“content_relate”);【给国外客人的感谢信】相关文章：1.酒店给客人的感谢信2.回复客人的感谢信3.国外老客户来访感谢信4.酒店对客人的感谢信5.给国外工作者的感谢信的范文6.欢迎客人的祝酒词7.致客人的道歉信8.给客人的道歉信9.对客人的慰问信。
讨论益处的作文模板英文
讨论益处的作文模板英文英文回答：There are numerous benefits to discussing a topic.First and foremost, it allows individuals to gain a deeper understanding of the subject matter. When we engage in discussions, we have the opportunity to share our thoughts, perspectives, and knowledge with others. This exchange of ideas helps us to expand our own understanding and learn from different viewpoints. For example, in a literature class, discussing a novel with classmates can provide uswith new insights and interpretations that we may not have considered on our own.Additionally, discussing a topic can enhance ourcritical thinking skills. Through conversations and debates, we are challenged to analyze and evaluate different arguments and evidence. This process of questioning and reasoning helps us to develop our own opinions and make informed decisions. For instance, in a business meeting,discussing the pros and cons of a particular strategy can lead to a more well-rounded and thoughtful decision-making process.Furthermore, discussing a topic can fostercollaboration and teamwork. When we engage in discussions, we are able to work together towards a common goal. By sharing ideas and brainstorming, we can come up with innovative solutions and strategies. This collaborative approach not only improves the quality of our work, butalso strengthens our relationships with others. For example, in a group project, discussing the project requirements and dividing tasks can lead to a more efficient and successful outcome.In conclusion, discussing a topic brings numerous benefits. It helps us to gain a deeper understanding, enhances our critical thinking skills, and fosters collaboration. Through discussions, we can learn from others, develop our own opinions, and work together towards common goals.中文回答：讨论一个话题有很多好处。
RH问题
1. Introduction It is a common problem in the numerical treatment of partial differential equations (PDEs) that most of the PDEs appearing in applications are defined on Rd where d is the dimension, i.e., on unbounded domains, whereas computers are generally able to deal with only finite domains. One popular approach in this context is to set up the problem on a finite domain and to impose transparent boundary conditions (TBC) which give the boundary data which would appear at this location if the initial value problem where treated on the whole Rd , or artificial boundary conditions approximating TBC. To this end a certain relation between Dirichlet and von Neumann data at the boundary has to be satisfied called the Dirichlet to von Neumann map, see e.g. [15, 31] for reviews of TBC approaches and in particular [1] for Schrödinger equations. An alternative approach is given by perfectly matched layers (PML) which were introduced by Bérenger [5] for the Maxwell equations. The idea is to join absorbing layers at the boundaries of the computational domain. The to be solved PDE is deformed in the layers in a way that the solution in the computational domain is not affected, and that it is rapidly dissipated in the layers. This PML approach was adapted to various equations, see for instance [26, 16] for Schrödinger equations. We use here the approach [36] that is similar to exterior complex scaling methods [25]. An interesting approach to treat PDEs on unbounded domains is to map infinite domains to finite domains. In a numerical context, this was apparently first used in [27] and later for the Schrödinger equation in [22]. Whereas [22] uses a finite difference method, [27] incorporates one of the first applications of a spectral
会展经济与管理新媒体营销中英文对照外文翻译文献
中英文对照外文翻译(文档含英文原文和中文翻译)原文:Social Networks and the Mass MediaAdapted from: American Political Science Review,2013,107 Social networking has become an every day part of many peoples’lives as evidenced by the huge user communities that are part of such networks. Facebook, for instance, was launched in February 2004 by Harvard under graduate students as an alternative to the traditional stud ent directory. In tended to cover interaction between students at Univers ities–Facebook enables individuals to encourage others to joint he network through personalized invitations, friend suggestions and creation of s pecialist groups. Today Facebook has a much wider take up than just s tudents at Universities. Facebook now facilitates interaction between peo ple by enabling sharing of common interests, videos, photos, etc. Sharin g,Some social network populations exceed that of large countries, for example Facebook has over 350 million active users. Social networks provide a platform to facilitate communication and sharing between user s, in an attempt to model real world relationships. Social networking ha s now also extended beyond communication between friends; for instanc e, there are a multitude of integrated applications that are now made a vailable by companies, and some organizations use such applications, su ch as Facebook Connect to authenticate users, i.e. they utilize a user’s Facebook credentials rather than requiring their own credentials(for exa mple the Calgary Airport authority in Canada uses Facebook Connect t o grant access to their WiFi network). This ability to combine a third party application (including its local data) to authenticate users demonstr ates the service-oriented approach to application development. By tappin g into an already established community around a particular social netw orking platform, it becomes unnecessary to require users to register wit h another system.The structure of a Social Network is essentially the formation of a dynamic virtual community with inherent trust relationships between fri ends. (Szmigin et al., 2006) identify how “relationship marketing” (ident ified as referring to all marketing activities directed towards establishing, developing and maintaining successful relational exchanges) can be faci litated through the creation of on-line communities. They discuss how o n-line communities can be used to facilitate interaction and bonding bet ween consumer and suppliers, intermediate parties and specific brands. Similarly, (Shang et al., 2006) discuss how brand loyalty can be achiev ed through various types of participation within an on-line community (focusing specifically on the –a virtual communit y of Apple users in Taiwan). They discuss the motivation for individua ls to promote certain products during on-line discussions (active particip ants) and for others to remain as lurkers (passive participants). The stu dy particularly focuses on the incentives for participants to contribute to an on-line community, based on the perception of a user about the de gree of relevance towards an object that is being discussed –focusing on both cognitive (based on utilitarian motive –concerning an individua l’s concern with the cost and benefit of the product or service) and aff ective (a value-expressive motive, referring to an individual’s interest in enhancing self-esteem or self-conception, and in projecting his/her desir ed self-image to the outside world through the product or service).It is also useful to understand, for instance, how such trust relation ships could be used as a foundation for resource (information, hardware, services) sharing. Cloud environments are typically focused on providin g low level abstractions of computation or storage. Using this approach, a user is able to access (on a short term/rental basis) capacity that is owned by another person or business (generally over a computer networ k). In this way, a user is able to outsource their computing requirement s to an external provider –limiting their exposure to cost associated wi th systems management and energy use. Computation and Storage Clou ds are complementary and act as building blocks from which applicatio ns can be constructed –using a technique referred to as “mash-ups”. S torage Clouds are gaining popularity as a way to extend the capabilities of storage-limited devices such as phones and other mobile devices. T here are also a multitude of commercial Cloud providers such as Amaz on EC2/S3, Google App Engine, Microsoft Azure and also many smalle r scale open clouds like Nimbus (Keahey et al., 2005) and Eucalyptus (Nurmi et al., 2009). A Social Cloud (Chard et al., 2010), on the other hand, is a scalable computing model in which virtualized resources co ntributed by users are dynamically provisioned amongst a group of frie nds. Compensation for use is optional as users may wish to share reso urces without payment, and rather utilize a reciprocal credit (or barter) based model (Andrade et al., 2010). In both cases guarantees are offered through customized Service Level Agreements (SLAs). In a sense, thi s model is similar to a Volunteer computing approach, in that friends s hare resources amongst each other for little to no gain. However, unlik e Volunteer models there is inherent accountability through existing frie nd relationships. There are a number of advantages gained by leveraging social networking platforms, in particular one can gain access to hug e user communities, can exploit existing user management functionality, and rely on pre-established trust formed through existing user relations hips.The author thanks Jason Barabas, Jon Bendor, Ted Carmines, Jami e Druckman, John Freeman, Matt Golder, Sona Golder, Bob Jackson, J enn Jerit, Kris Kanthak, ?zge Kemahlioglu, Charlotte Lee, Valerie Marti nez-Ebers, Adam Meirowitz, Scott McClurg, Will Moore, Chris Reenock, John Ryan, John Scholz, Jake Shapiro, Anand Sokhey, Jeff Staton, Ji m Stimson, Craig Volden, Jon Woon, four very helpful anonymous revi ewers, and audiences in the Political Economics group at the Stanford GSB, Political Science departments at FSU, GWU, Minnesota, Pittsburg h, and Stony Brook, and the Frank Batten School of Leadership and P ublic Policy at UVa. Any errors are my own.To begin to answer this question, I develop a novel theory of aggr egate opinion and behavior. The theory considers a heterogeneous popul ation of individuals who must choose between dichotomous options. It incorporates the interaction of social network and mass media influences at the individual level; its key assumption is that the more others cho ose an option, the more one is apt to do so as well. In the theory, soc ial networks provide information about the choices of those to whom o ne is directly connected, while the mass media provide (potentially bias ed) information about aggregate choice. The theory thus applies to, for example, voter turnout and political participation (e.g., Gerber, Green, a nd Larimer 2008; Lake and Huckfeldt 1998; Leighley 1990; McClurg 2 003; Rolfe 2012), opinion formation (e.g., Beck et al. 2002; Druckman and Nelson 2003; Huckfeldt and Sprague 1995), protests and social mo vements (e.g., Kuran 1991; McAdam 1986), and vote choice (e.g., Beck 2002; Huckfeldt and Sprague 1995; Ryan 2011; Sinclair 2012; Sokhey and McClurg 2012).Three major results follow from this theory. All hold both when in dividuals treat media identically and when they select into media in lin e with their preferences. First, understanding the aggregate effect of the media generally requires considering social networks, because social ne twork structure conditions media's impact. For example, additional weak ties between disparate social groups can reduce the media's impact, an d the presence of unified social elites can eliminate the media's impact entirely in the aggregate. Empirical studies of media impact that fail t o consider media's interaction with social networks risk bias.Second, social networks can amplify the effect of media bias. A bi ased media outlet that systematically under- or over-reports a poll of th e population by a only a few percentage points can in some cases swi ng aggregate behavior (e.g., turnout or vote share) by over 20% in eith er direction due to positive feedback within the network. Open advocate s in the media can have a yet larger impact even when not comparativ ely influential. Unified social elites limit the effect of media bias, but c annot fully counter an advocate; selection into media, made ever easier with technological improvements, tends to enhance the effect of bias. We should therefore expect media bias to become increasingly importan t to aggregate behavior.AN INDIVIDUAL-LEVEL THEORY OF AGGREGATE BEHAVIO RThough I present a theory of aggregate behavior, it is based on in dividual-level assumptions informed by what we know about the way p ersonal characteristics, social networks, and mass media outlets affect in dividual behavior. Due to this, the theory can explore the effect that int eractions between these three factors have on aggregate behavior. As i mportantly, the theory incorporates empirically realistic heterogeneity acr oss people in allthree factors.Additionally, people are exposed to individuals, groups, and organiz ations external to one's network, such as mass media outlets, state prop aganda, national party leaders, NGOs, and Internet personalities. These outlets can provide information, increasing political knowledge.As this small sampling of large literatures indicates, individuals' de cisions are influenced by the information they obtain via both local soc ial networks and global media outlets. However, comparatively little sch olarship has explored the three-way interaction of personal characteristic s, social networks, and mediaIn the second type of bias, which I call advocacy, the media outle t simply states a preference for one of the options, providing no inform ation about aggregate support. The goal in advocacy is to sway the po pulation toward one or the other option. As before, many goals could u nderlie advocacy beyond just the support of a biased media outlet's pre ferences. Advocacy represents the editorial power of the media or the i nfluence of an external actor; it is a "one-message" model (Zaller 1992).I focus my analysis in all three sections on the case in which one of the two options is the status quo, and all individuals begin supporti ng it. For political participation and social movements, the status quo is not participating. For opinion formation and vote choice, the status qu o is an existing option such as a policy in place or an incumbent politician, as contrasted with an alternative such as a newly proposed policy or a challenging politician. For simplicity I subsequently call participat ion the option that is not the status quo; this should be read as "partici pation in support of" the option that is not the status quo in contexts o ther than political participation or social movements.In my analysis I simultaneously vary media strength, network prop erties, media bias, and, for two outlets, the strength of the L outlet. Th ough I keep my analysis to two biased outlets, it can easily be extende d to multiple biased outlets with the addition of parameters dictating th eir relative strengths.二、译文社交网络和大众传媒社交网络已经成为许多人每天生活的一部分，即证明了这种网络庞大的用户群体。
关于英文感谢信范文集锦6篇
关于英文感谢信范文集锦6篇英文感谢信篇1Dear Mr. Santos,I'm Luo Li. At this moment, I'm honored to express our sincere thanks to you on behalf of my classmates.We do appreciate everything that you've done for us. We've been very lucky to have you as our English teacher in the past years. With your help, everybody has made progress both in English learning and school life. We've enjoyed your teaching and guidance a lot. Your humorous stories, big smiles and encouraging words have already rooted in our memories. Since you will leave soon. we wish you a pleasant journey back home and a happy life there. We'll miss you. Thanks again,Mr. Santos.英文感谢信篇2在初中三年的学习生活中，你一定遇到过很多老师，现在请你选择其中对你帮助最大的一位老师，给他(她)写一封感谢信，谈谈你对他(她)的印象，回忆一下他(她)是怎么帮助你的，并表达你对他(她)的祝福。
信的开头和落款已给出，不计词数。
提示词：kind, help, encourage, thanks, hope本题要求我们给对自己帮助最大的老师写一封感谢信，因为是自己亲身经历的，又是写给自己的老师，同学们一定有千言万语要对他(她)说。
for student-acknowledgement
We thank Mr. A for encouraging this work. We also thank Mr. B for his helpful comments. I am greatly indebted to Mr. A for discussion about this paper and for the guidance over many years. The authors wish to acknowledge the continuous support of the University of X.
表示谢意的理由
对文稿的意见 for comments on the manuscript 有益的讨论 for useful discussion 建设性建议 for construction suggestions 有教益的信札赐教 for helpful correspondence
Sample 1: The authors express their gratitude to A, B and C for many helpful discussions. Detailed comments by the editor D greatly improved the paper. We benefit from seminar participants at X, Y, and Z. The authors acknowledge support from NSF Grant SBR 9709887 and 9706663 respectively.
宝贵的指导 for valuable guidance 向作者提供研究资助 for granting the writer a research scholarship 对本文初稿提出宝贵意见 for their valuable comments on an earlier version of this manuscript
大学英语综合教程Unit6
This article also provides in-depth analysis of some common grammar difficulties, such as "sub junction mood", "irregular verbs", etc., to help readers overcome these learning difficulties.
Reading for Pleasure
Encouraging engagement of reading through a variety of texts, genres, and topics, promoting a lifelong love of reading
Writing skills
Content Development
Developing the ability to plan and organize ideas effectively, ensuring clear and coherent arguments or narratives
Vocabulary and Grammar
Vocabulary Building
Expanding the range of words and phrases understanding and used correctly, enhancing comprehension and expression
Speed of Reading
Increasing the rate at which materials can be read, while maintaining comprehension and accuracy
参加英语俱乐部英文作文
参加英语俱乐部英文作文I have been a member of the English Club for quite some time now and I must say, it has been an incredible experience. The club has given me the opportunity to improve my English skills in a fun and interactive way. We have engaging discussions, play language games, and even have mock debates. It's a great way to practice speaking English in a relaxed and supportive environment.One thing that I really enjoy about the English Club is the diversity of its members. We have people from all walks of life, different nationalities, and varying levels of English proficiency. This diversity adds so much richness to our conversations and allows us to learn from eachother's unique perspectives. It's truly amazing how language can bring people together and create a sense of community.Another aspect of the English Club that I appreciate is the focus on real-life situations. We often have role-playactivities where we simulate everyday scenarios like ordering food at a restaurant or negotiating a price at a market. These activities not only improve our languageskills but also prepare us for real-life situations wherewe may need to communicate in English. It's a practical approach to learning that I find very effective.The English Club also organizes regular outings and events, which I find really exciting. We have gone on field trips to museums, attended English-speaking theater performances, and even had a karaoke night where we sang English songs. These activities not only allow us topractice our English in different settings but also createa sense of camaraderie among the members. It's a great wayto bond with fellow English enthusiasts and make new friends.I must mention the dedicated and passionate teachers who lead the English Club. They go above and beyond to create a welcoming and stimulating environment for us to learn. They come up with interesting topics for discussions, provide helpful feedback during debates, and offer valuabletips to improve our language skills. Their enthusiasm is contagious and it motivates us to keep pushing ourselves to become better English speakers.In conclusion, being a member of the English Club has been an enriching experience for me. It has not only helped me improve my English skills but also allowed me to meet amazing people from different backgrounds. The club's focus on real-life situations and its diverse range of activities make learning English enjoyable and practical. I amgrateful for the opportunity to be a part of such a dynamic and supportive community.。
放下语文课本我不禁想起作文600,初一
放下语文课本我不禁想起作文600,初一1.爱读书是一种美好的习惯。
Love of reading is a wonderful habit.2.课外阅读可以丰富我们的知识。
Extracurricular reading can enrich our knowledge.3.写作文是一个很好的锻炼。
Writing compositions is a good exercise.4.语文课是我最喜欢的课程之一。
Chinese class is one of my favorite subjects.5.语文老师总是鼓励我们多读多写。
The Chinese teacher always encourages us to read and write more.6.阅读经典名著有助于提高语文水平。
Reading classic works helps to improve Chinese proficiency.7.课文中的名句让我印象深刻。
The famous sentences in the text impressed me deeply.8.学好语文对我以后的发展很重要。
It is important for the future development to learn Chinese well.9.书山有路勤为径，学海无涯苦作舟。
There is a way in the book mountain, diligence is the path; the sea of learning has no bound, hard work is the boat.10.用心去读书，会有很大收获。
Reading carefully will bring great harvest.11.课外阅读是提高语文素养的有效途径。
Extracurricular reading is an effective way to improve Chinese literacy.12.在作文中表达自己的想法很重要。
我想要加入英语俱乐部的英语作文初一
我想要加入英语俱乐部的英语作文初一全文共3篇示例，供读者参考篇1I Want to Join the English ClubHi there! My name is Emma and I'm a 7th grader at Central Middle School. I really want to join the English Club this year and I'm going to tell you all about why.First off, I absolutely love the English language. I know that might sound a bit weird coming from a 12-year-old, but it's true! I've always loved reading books, writing stories, and just playing around with words in general. There's something so cool about how you can string different words together to create whatever picture or idea you want in someone's mind.English is such a rich and dynamic language too, with words borrowed from so many other languages over the centuries. We have words derived from German, French, Latin, Greek, and even further afield languages like Arabic, Hindi, Chinese, and Native American languages. I find the history and evolution of English fascinating.Whenever I'm reading, there's always a handful of words I don't fully know, so I have to look them up. But instead of seeing this as a chore, I revel in it! Learning new vocabulary words is like unlocking another tiny piece of the English language's vast treasury. Will that new word turn out to have an interesting etymological background tracing back to ancient roots? Or will it be a more recent addition, maybe born out of slang or innovative word blend? Who knows, but I can't wait to find out!My love of English doesn't stop at vocabulary though. I'm also a huge fan of proper grammar, syntax, and all the intricate rules that govern how we construct sentences and paragraphs. There's just something so satisfying about a beautifully-crafted sentence that flows smoothly while obeying all the important principles. Perfecting grammar is like solving a fun little puzzle.I put a ton of effort into my writing assignments for English class, not because I have to, but because I genuinely enjoy wrestling with words until I've molded them into something I'm proud of. Whether it's a creative narrative or an analytical essay, the process of choosing just the right phrases to convey my thoughts precisely is an incredibly rewarding experience.Another reason I'm eager to join English Club is because I relish opportunities to discuss and analyze literature. There areso many rich themes, symbols, motifs, and other layers of meaning to unearth in Classical works and contemporary novels alike. I love picking apart passages with my peers and Prof. Henderson to see what creative spark or real-world observation the author was trying to capture.English Club would also allow me to spend more time reading, which is one of my absolute favorite activities. Whether it's losing myself in a iconic old novel like To Kill a Mockingbird or The Catcher in the Rye, or devouring the latest young adult best-seller, reading is when I'm at my happiest. Those moments when a beautifully-written paragraph or turn of phrase just clicks and reverberates inside you... that's pure bliss for me!I have so many thoughts and opinions about books that it'll be awesome to discuss them in a club setting instead of just rambling to my poor parents all the time. Will others interpret that ambiguous ending the same way I did? What did people think of how the author developed that key character over the course of the story? I can't wait to engage in those kinds of debates and hear some fresh perspectives!Reading and analyzing literature doesn't just activate the language part of my brain either. All of that critical thinking and investigation of deeper meanings aids my development in otheracademic areas too. The skills I've picked up from close reading and literary analysis - like identifying context clues, tracing logical argumentation, explicating metaphors and symbols - have helped me tremendously when I'm working on assignments for subjects like history, science, and even math. Joining English Club would give me additional practice honing those crucial skills.I'd also love the chance to work on my speaking abilities through activities like debates, presentations, and group discussions in English Club. While I'm very confident with my reading and writing, I do get a bit nervous sometimes when I have to speak up in front of others. Having more low-pressure opportunities to practice my verbal communication skills in a club setting would help build my confidence over time.What really excites me too is the prospect of getting feedback on my writing from Mrs. Ramirez, the English teacher who oversees the club. Her comments on my essays and stories this year have already proven so helpful for improving my writing.I know if I joined English Club, her guidance and insight would accelerate my growth as a writer even more. Having a mentor who shares my passion for language and literature would be incredible.Another big perk of belonging to English Club? Surrounding myself with other students who love English as much as I do! Making friends who share my zeal for reading, writing, and wordsmithing seems too good to be true. While most of my current friends think I'm a bit of a eccentric wordnerd (their term, not mine!), English Club would be filled with likeminded kids who geek out over grammar and metaphors just as much as I do. What a dream!Just imagine getting together after school to debate the finer points of author's diction and writing styles. Or doing fun group activities like linguistic scavenger hunts and grammar games. Maybe we could even take little field trips to book readings by visiting authors, or Shakespeare performances in the park. The creative possibilities for literary enrichment seem endless!How cool would it be to collaborate on writing projects too? We could all workshop each other's short stories or poems and help refine them before submitting to competitions. Maybe we could even take on the ambitious goal of putting together a student literary magazine to showcase some of Central Middle School's finest creative writing. That would be such an awesome accomplishment to put on my high school applications!I suppose one last benefit I should mention is how joining English Club would provide some nice extracurricular credentials to make my academic record look more impressive. Not only would it demonstrate my passion for language and literature, but it would also show my commitment to going above and beyond for a subject I love. Colleges do seem to favor applicants who pursue their interests outside of school through clubs and activities.But honestly, that last part isn't my main motivation for wanting to join English Club. Sure, it would be a resume booster, but I'm way more excited about actually gettingtheopportunity to immerse myself further in my favorite subject. For me, it's all about doing something I truly enjoy and finding a community of others who share that same joy for the magic and power of the English language.So that's why I can't wait to submit my application for Central Middle School's English Club! I really hope I get accepted in because it would allow me to nourish my ardor for English through fantastic opportunities for enrichment, mentorship, socialization, and creative expression. My schedule is completely wide open after school to commit myself fully. Now I just need towork on polishing up my application essay...perhaps I could have Mrs. Ramirez from English class review it first?Anyway, thanks for letting me nerd out and gush about my love of English! Hopefully you can see why joining the club would mean so much to me. My fingers are tightly crossed that the club moderators share their decision soon. Let me know if you need any help proofreading or editing your own work sometime!篇2I Want to Join the English ClubEver since I was a little kid, I've been completely fascinated by the English language. I still vividly remember the first time I heard English being spoken – it was in a movie my parents were watching. The sounds and rhythms were so strange and melodic to my young ears. I begged my parents to teach me some of the words I had heard, like "hello" and "goodbye." They patiently explained the meanings, wrote out the words for me, and helped me practice the unfamiliar pronunciations over and over again.From that point on, I was hooked. I drove my parents crazy asking them about every stray English word or phrase I happened to encounter, whether it was on a sign, in a book, orplaying in the background of a TV show. They didn't know too much English themselves, but they encouraged my interest as best they could. On my 6th birthday, they surprised me with my very first English-Chinese dictionary and some simple English storybooks. I treasured those books and read them repeatedly until I had largely committed them to memory.In primary school, I threw myself wholeheartedly into studying English, much to the amusement of my classmates who mostly saw it as a tedious requirement. While they groaned during English class, I was utterly captivated, hanging on every word the teacher said. I loved learning about the convoluted spelling rules, quirky idioms, and mind-bending grammar exceptions that made English so challenging yet endlessly fascinating. At home, I would spend hours poring over my English workbooks and textbooks, practicing the vocabulary and constructing my own rudimentary sentences.Even as a young student, I recognized that English represented a bridge to a much larger world beyond the confines of my hometown. Music, movies, books, and video games from the West all became more richly accessible to me as my English skills slowly improved year after year. I started teaching myself about the diverse cultures of English-speakingcountries by reading encyclopedias and surfing the very basics websites that were online back then. The incredible diversity of the Anglophone world seemed to beckon me.Now that I'm in middle school, my passion for English has only grown more intense. My speaking, reading, and writing abilities have become quite decent, if I say so myself, but I'm desperate to take my English to the next level – and that's why I absolutely need to join the English club here at school.From what I know, the English club is a wonderful community of students who share my zeal for the English language and enthusiasm for learning about Western culture. The club meets weekly to practice conversational English through games, discussions, debates, and other interactive activities. They host foreign guests and even take field trips to English corners in town to dialogue with native speakers. I can only imagine how rapidly my oral English skills would progress if I could take advantage of such invaluable immersive opportunities.But the benefits of the English club go far beyond just improving our mastery of the language itself. From speaking with current members, I've learned that the club really opens doors to experiencing English in a rich, multidimensional way.They celebrate holidays and cultural festivals fromEnglish-speaking nations. They watch movies, read books, and listen to music while analyzing the deeper cultural context. They even have special sessions for members to share personal connections to the Anglophone world, whether through travel experiences, pen pals, cross-cultural friendships, or family heritage.To me, joining the English club would be like finding a home away from home – a space where I could be myself and dive headfirst into my greatest passion without any shyness or inhibition. I know with certainty that being an active member would not only amplify my English abilities, but help me to become a more globally-minded, culturally-aware, and open person in general.My intense zeal for becoming fluent in English stems from a sincere belief in its importance. As a world language, English represents a bridge for cross-cultural communication and understanding between East and West. By improving my grasp of both the linguistic and cultural dimensions of English, I'll be better equipped to serve as an ambassador for my own heritage while simultaneously developing a deeper appreciation fordiversity. In our increasingly globalized world, such skills are only going to become exponentially more vital.But beyond those broader impacts, being able to wield English fluently and authentically will empower me to more fully engage with the wealth of incredible art, literature, media, and knowledge that the Western world has to offer. From Shakespearean plays and Dickinson's poetry to the libraries of online information and the latest sci-fi movies, English represents an entry point into vast new universes of culture and ideas that I'm aching to explore. A strong mastery of the English language will be the key that unlocks those doors for me.Ultimately, though, my deep passion for English originates from a much simpler place – a sense of pure intellectual joy and wonder at the complexity, nuances, and beauty of this language unlike my native tongue. English is an incredibly expressive vehicle for conveying emotion, telling stories, cracking jokes, and expressing abstract thoughts. Its rich history of integrating words and constructions from myriad global influences have made it one of the most flexible, dynamic languages on Earth. No matter how many years I devote to learning English, I know there will always be fresh layers to uncover and savor.So in summary, being admitted into the English club would be an absolute dream come true for me. I can't imagine a better way to take my English studies to the next level. I'm wholeheartedly committed to active participation and hard work to keep growing my skills. And perhaps someday after reaching full fluency, I might be able to contribute to the club by mentoring younger students and spreading my own passion for English to a new generation. This club has played an instrumental role in shaping the lives and opened innumerable doors for so many students across the years. I can only hope I'll be given the amazing honor of becoming a member and continuing that tradition. Thank you for your consideration!篇3My Big Dream to Join the English ClubHi there! My name is Jessica and I'm in 7th grade. I'm really excited to tell you about my big dream - I want to join the English club at my school! I know it might seem like a small thing, but to me it means a whole lot.You see, I've always loved the English language. I can still remember way back in kindergarten when I started learning the alphabet song and simple words like "cat" and "dog." It was likea light went on in my brain and I thought "This is so cool! I want to learn all of this!"Ever since then, English has been my favorite subject in school. I love learning new vocabulary words and practicing conversations with my classmates. I even started reading more difficult English books for fun instead of just picture books. My parents were so proud when my reading level tested into the highest level at the library!That's when they told me about the English club at my middle school. They said it's a place where students who love English can get together and take their skills to the next level. We get to do all sorts of fun activities like reading great novels, watching movies and plays, and even putting on our own performances. How amazing is that?At first I was nervous about joining because I didn't know anyone else who was a member. What if I was the only one who loved English that much? Or worse, what if the other kids thought I was a nerd for being so into it? My mind was filled with doubts.But then my English teacher Ms. Roberts encouraged me to go for it. She said she could tell from my work in class how much I enjoyed learning about the language. Ms. Roberts told me theEnglish club was a safe space where I could be myself and not feel weird about being passionate about English. There would be other kids just like me who loved it too!That's when I decided - I'm going to join the English club no matter what. Learning English and getting better at it is so important to me. I want to travel the world one day and being fluent in English will let me talk to people from all over. Maybe I'll even have a career some day that involves English in a major way. Who knows where this passion could take me?Of course, I'm still a little nervous about actually joining the club. Making new friends and putting myself out there has always been a struggle for me. But I know that this is something I really want and need to do to grow. Ms. Roberts said stepping out of our comfort zones is how we reach our full potential.So that's my big dream - to join the English club here at my middle school. It's a way for me to take my English abilities to the next level. I'll be surrounded by other students who share my love for this amazing language. We can learn from each other and have fun together through all the great activities.I'm hoping that being in the English club will help me become more confident speaking, reading, and writing English. It's going to get me ready for harder English classes in highschool and college too. This is just the first step towards my dream of being truly fluent and using English in whatever career I choose.Who knows, maybe I'll even try my hand at writing the next big novel in English one day! For now though, I'm going to focus on working hard, making new friends, and pursuing this passion of mine. Wish me luck - I'm about to turn my dream into reality!。
关于课程学习反馈的邮件英语作文开头
关于课程学习反馈的邮件英语作文开头全文共3篇示例，供读者参考篇1Dear Professor Wilson,I hope this email finds you well. As the semester draws to a close, I wanted to take the opportunity to provide some feedback on the courses I have taken this term. Reflecting on my academic journey is not only valuable for my own growth, but it also allows me to express my gratitude and share insights that could potentially enhance the learning experience for future students.Beginning with your course, Introduction to Anthropology, I must commend the engaging and thought-provoking nature of the lectures. Your ability to weave intricate cultural narratives with theoretical frameworks truly captivated my intellectual curiosity. The diverse range of case studies you presented allowed us to explore the richness of human diversity from a multitude of perspectives, fostering a deeper appreciation for the complexities that shape our global community.One aspect of the course that particularly resonated with me was the emphasis on critical thinking and open discourse. The weekly discussion sections provided a safe space for us to voice our opinions, challenge preconceived notions, and engage in respectful debates. This intellectual exchange not only strengthened our understanding of the course material but also honed our ability to articulate our thoughts coherently and consider alternative viewpoints with empathy and nuance.Furthermore, I commend your commitment to incorporating diverse voices and perspectives into the curriculum...篇2Dear Professor Smith,I wanted to reach out and provide some feedback on your ENG 201 course that I took this past semester. Overall, I really enjoyed the class and felt that I learned a tremendous amount about literary analysis and academic writing. Your passion for the subject material was evident in every lecture, and your thoughtful discussion questions encouraged us students to think critically about the texts in new and insightful ways.One aspect of the course that was particularly valuable for me was the peer review process for our essays. Being able toexchange drafts with classmates and provide/receive constructive criticism was extremely helpful for improving my writing skills. The feedback I received alerted me to areas where I needed to clarify my arguments or strengthen my evidence. It was a little intimidating at first to critique others' work, but the anonymous nature of the process made it easier to be honest and direct.The only suggestion I might make is to potentially incorporate a few more contemporary works into the reading list. While I understand the importance of establishing a strong literary foundation by studying classic texts, I also think analyzing some recent award-winning novels or plays could make the course feel more relevant and applicable to our current era. That said, the curriculum was already jam-packed, so I know adding more material is always a tough balancing act.In any case, I'm grateful for such a rewarding andthought-provoking learning experience. The skills I developed in your class, from close reading and critical analysis to research and composition, will undoubtedly prove invaluable as I continue my studies. Thank you again for your excellent teaching and for challenging me to become a better writer and thinker.篇3Reflecting on My Learning ExperienceAs another semester comes to a close, I find myself looking back on the courses I've taken and the knowledge I've gained. It's a valuable exercise, not just for my own personal growth, but also to provide constructive feedback that can help shape the learning experience for future students.This semester, I was particularly inspired by Professor Smith's Introduction to Anthropology course. From the very first lecture, I was captivated by the way she wove together complex theories and real-world examples, making the material not only informative but also deeply engaging. Her passion for the subject was infectious, and her willingness to encourage critical thinking and open discussions created an environment where I felt comfortable exploring new ideas and challenging my own assumptions.However, I must admit that there were moments when I struggled to keep up with the pace of the course. While Professor Smith's lectures were always well-organized and comprehensive, the sheer volume of information covered in each session sometimes left me feeling overwhelmed. Perhaps breaking down the material into smaller, more digestible chunksor incorporating more interactive activities could have helped reinforce the key concepts more effectively.Despite this challenge, I found the course readings to be invaluable resources. The curated selection of articles, case studies, and excerpts from seminal works provided a rich tapestry of perspectives, allowing me to delve deeper into the topics that piqued my interest. I particularly enjoyed the way Professor Smith encouraged us to draw connections between different sources, fostering a more holistic understanding of the discipline.As I reflect on my experience in this course, I am filled with a sense of gratitude for the knowledge I've gained and the skills I've developed. At the same time, I recognize the importance of providing honest and constructive feedback, as it is through this dialogue that we can continually improve and enhance the learning experience for all.。
我和同班同学交流是困难的解决事例英语作文
我和同班同学交流是困难的解决事例英语作文全文共3篇示例，供读者参考篇1Title: Overcoming Communication Difficulties with ClassmatesIntroduction:As a student, communication with classmates is an essential part of daily school life. However, for some individuals, including myself, interacting with classmates can be a challenge. In this essay, I will discuss the reasons behind this difficulty and share some strategies I have used to overcome it.Reasons for Difficulty in Communication:There are several reasons why I find it hard to communicate with my classmates. One of the main reasons is shyness. I am naturally introverted and find it difficult to initiate conversations with people I don't know well. This shyness can make it hard for me to participate in group discussions or approach classmates for help with assignments.Another reason for the difficulty in communication is a language barrier. As an international student, English is not my first language, and I sometimes struggle to find the right words to express myself clearly. This can lead to misunderstandings and make it even harder to communicate effectively with my classmates.Strategies for Overcoming Communication Difficulties:Despite these challenges, I have found several strategies that have helped me improve my communication with classmates. One of the most effective strategies has been to actively participate in class activities. By engaging in group discussions, asking questions, and sharing my ideas, I have been able to build rapport with my classmates and feel more confident in my communication skills.Another helpful strategy has been to seek out opportunities for one-on-one interactions with classmates. By working on group projects or studying together with a classmate, I have been able to develop deeper connections and overcome some of the social barriers that have hindered my communication in the past.In addition, I have also made an effort to improve my English language skills by practicing speaking and listening outside ofthe classroom. I have participated in language exchange programs, joined conversation clubs, and read English books and articles to expand my vocabulary and improve my fluency.Conclusion:Communication with classmates is an important aspect of the school experience, and overcoming difficulties in this area can greatly enhance the learning environment. By recognizing the reasons behind my communication challenges and implementing strategies to improve my skills, I have been able to build stronger relationships with my classmates and feel more confident in my ability to communicate effectively. I hope that by sharing my experiences, others facing similar challenges can also find ways to overcome their communication difficulties and thrive in the classroom.篇2I have always found it difficult to communicate with my classmates in school. As an introvert, I often struggle to initiate conversations and connect with others in a meaningful way. This made it challenging for me to build relationships with my classmates and participate in group activities.One particular incident that stands out to me is when we were assigned a group project in our English class. I was paired with three classmates who I didn't know very well. Throughout the duration of the project, I found it hard to contribute my ideas and opinions during our group discussions. I often felt ignored and overlooked, which only served to reinforce my feelings of isolation and inadequacy.As the deadline for the project approached, I knew that I needed to find a way to overcome my difficulties in communicating with my classmates. I decided to take a proactive approach and scheduled a meeting with my group members outside of class. During this meeting, I made a conscious effort to speak up and share my thoughts with them. I also made an effort to actively listen to their ideas and opinions, which helped me to better understand where they were coming from.To my surprise, my classmates were receptive to my efforts to improve communication within our group. They appreciated my willingness to be more open and engaged in our discussions. By the end of the project, we were able to work together effectively and produce a well-researched and cohesive presentation.This experience taught me the importance of stepping out of my comfort zone and making an effort to communicate with others. It also showed me that by taking small steps towards improving my communication skills, I could overcome the barriers that had previously hindered my ability to connect with my classmates. I now feel more confident in my interactions with others and am more willing to engage in conversations and activities with my peers.篇3Title: How I Overcame Communication Difficulties with My ClassmatesCommunication is key in building relationships and forming connections with others. However, for me, communicating with my classmates has always been a challenge. As an introverted person, I often find it hard to initiate conversations and engage in group discussions. This has made it difficult for me to connect with my peers and form meaningful relationships in class.Despite these challenges, I was determined to overcome my communication difficulties and improve my social skills. I realized that in order to build strong relationships with my classmates, I needed to step out of my comfort zone and actively seek outopportunities to engage with them. Here are some steps I took to improve my communication skills and connect with my classmates:1. Joining group projects: I actively volunteered to participate in group projects and assignments. This helped me to interact with my classmates in a structured environment and work together towards a common goal. Through these group projects, I was able to break the ice with my classmates and gradually form connections with them.2. Participating in class discussions: Although speaking up in class was daunting for me, I made a conscious effort to overcome my fears and participate in class discussions. I started by sharing my thoughts and ideas with my classmates in a small group setting before gradually speaking up in larger class discussions. This helped me to build my confidence and improve my communication skills.3. Attending extracurricular activities: I started attending extracurricular activities such as sports events, club meetings, and school gatherings. These activities provided me with opportunities to interact with my classmates in a more relaxed and informal setting. By engaging in these activities, I was able tosocialize with my peers outside of the classroom and form genuine connections with them.4. Seeking help from teachers: I reached out to my teachers for guidance and support in improving my communication skills.I asked for feedback on my contributions in class, participated in communication workshops, and sought advice on how to engage with my classmates effectively. With the help of my teachers, I was able to identify areas for improvement and work towards developing better communication habits.5. Being open-minded and empathetic: I learned to approach conversations with an open mind and actively listen to my classmates' perspectives. I showed genuine interest in their opinions, experiences, and interests, which helped me to build rapport with them and form authentic relationships. By being empathetic and understanding towards my classmates, I was able to connect with them on a deeper level and foster meaningful connections.Through these steps, I was able to overcome my communication difficulties and form strong relationships with my classmates. I learned the importance of stepping out of my comfort zone, being proactive in seeking opportunities to engage with others, and showing empathy and understandingtowards my peers. By improving my communication skills and connecting with my classmates, I was able to build lasting friendships and create a positive social environment in my class.。
英语参加会议作文
After the conference, take some time to reflect on your experience and what you have learned. Consider how the knowledge and insights gained can be applied to your own work or research, and think about how the connections made at the conference can be nurtured and developed in the future. It can also be helpful to share your experience with colleagues or peers who were not able to attend the erence, as this can help to disseminate the knowledge and insights gained.
一、Preparation before the conference
Before attending the conference, it is important to familiarize oneself with the conference theme and topics, as well as the key speakers and their backgrounds. It is also helpful to do some background reading on the subjects that will be discussed, so that you can actively engage in the conversations and understand the presentations. Additionally, it is beneficial to brush up on your English language skills, particularly in terms of listening and speaking, as the conference will likely be conducted in English.
A THEORY OF FIRM SCOPE
THE QUARTERLY JOURNAL OF ECONOMICSVol.CXXV May2010Issue2A THEORY OF FIRM SCOPE∗O LIVER H ART AND B ENGT H OLMSTROMThe formal literature onfirm boundaries has assumed that ex post conflicts are resolved through bargaining.In reality,parties often simply exercise their decision rights.We develop a model,based on shading,in which the use of authority has a central role.We consider twofirms deciding whether to adopt a common standard. Nonintegratedfirms may fail to coordinate if onefirm loses.An integratedfirm can internalize the externality,but puts insufficient weight on employee benefits. We use our approach to understand why Cisco acquired StrataCom,a provider of new transmission technology.We also analyze delegation.I.I NTRODUCTIONIn the last twenty years or so,a theoretical literature has de-veloped that argues that the boundaries offirms—and the alloca-tion of asset ownership—can be understood in terms of incomplete contracts and property rights.The basic idea behind the literature is thatfirm boundaries define the allocation of residual control rights,and these matter in a world of incomplete contracts.In the ∗This is an extensively revised version of two earlier papers that circulated as“A Theory of Firm Scope”and“Vision and Firm Scope.”Some of the materialpresented here formed part of thefirst author’s Munich Lectures(University of Munich,November2001),Arrow Lectures(Stanford University,May2002),Karl Borch Lecture(Bergen,May2003),and Mattioli Lectures(Milan,November2003). We are especially grateful to Andrei Shleifer for insightful comments.We would also like to thank Philippe Aghion,George Baker,Lucian Bebchuk,Patrick Bolton, Pablo Casas-Arce,Mathias Dewatripont,Douglas Diamond,Aaron Edlin,Florian Englmaier,Robert Gibbons,Richard Holden,Bob Inman,Louis Kaplow,Bentley MacLeod,Meg Meyer,Enrico Perotti,David Scharfstein,Chris Snyder,Jeremy Stein,Lars Stole,Eric van den Steen,and seminar audiences at CESifo,Univer-sity of Munich,Harvard University,London School of Economics,George Washing-ton University,Stanford University,the Summer2002Economic Theory Workshop at Gerzensee,Switzerland,and the University of Zurich for helpful discussions. Finally,we have benefited from the very constructive suggestions of the editor and three referees.Research support from the National Science Foundation is gratefully acknowledged.C 2010by the President and Fellows of Harvard College and the Massachusetts Institute of Technology.The Quarterly Journal of Economics,May2010483484QUARTERLY JOURNAL OF ECONOMICSstandard property rights model,parties write contracts that are ex ante incomplete but can be completed ex post.The ability to exercise residual control rights improves the ex post bargaining position of an asset owner and thereby increases his or her incen-tive to make relationship-specific investments.As a consequence, it is optimal to assign asset ownership to those who have the most important relationship-specific investments.1Although the property rights approach provides a clear ex-planation of the costs and benefits of integration,the theory has a number of features that have limited its applicability.2One that we focus on here is the assumption that ex post conflicts are re-solved through bargaining with side payments.Although direct empirical evidence on this topic is not readily available,casual inspection suggests that bargaining with unrestricted side pay-ments is not ubiquitous.Many decisions made in afirm will be carried out without consultation or negotiation with otherfirms even when these decisions impact the otherfirms in a major way.It is rare,for instance,for afirm to go to a competitor with the inten-tion of extracting side payments for avoiding aggressive moves.3 We present a new model offirm boundaries,which is designed to deal with strategic decisions that are taken in the absence of ex post bargaining.To justify the use of authority rather than bar-gaining,we adopt the“contracts as reference points”approach of Hart and Moore(2008).According to this approach,a contract(in our model,an organizational form),negotiated under competitive conditions,circumscribes or delineates parties’senses of entitle-ment.Parties do not feel entitled to outcomes outside the contract, but may have different views of what they are entitled to within the contract.More specifically,each side interprets the contract in a way that is most favorable to him.When he does not get the most favored outcome within the contract,he feels aggrieved and shades by performing in a perfunctory rather than a consummate fashion,creating deadweight losses.Given these assumptions,a more open-ended contract leads to more aggrievement,implying1.See Grossman and Hart(1986),Hart and Moore(1990),and Hart(1995). This literature builds on the earlier transaction cost literature of Williamson(1975, 1985)and Klein,Crawford,and Alchian(1978).2.For a discussion of this,see Holmstrom and Roberts(1998)and Holmstrom (1999).3.Of course,where there is an opportunity for mutual gains,afirm may approach anotherfirm to explore various ways of cooperating,either through the market or through a joint venture or merger.However,it is also possible that the parties will simply do what is unilaterally in their best interest.A THEORY OF FIRM SCOPE485 that ex post bargaining with side payments is costly.4We rule out renegotiation on these grounds.Our model comprises two units that have a lateral relation-ship(this is another departure from the literature,which has fo-cused on vertical integration).We think of a unit as an irreducible set of activities that it would be meaningless to break up further. Each unit is operated by a manager and has a decision that af-fects the other unit;that is,there are externalities.We have in mind strategic decisions that are so significant that they warrant consideration of an organizational structure that best supports them.For example,the units may be deciding whether to adopt a common standard or platform for their technology or product.As an application,we will use the model to understand Cisco’s approach to acquisitions,especially its decision to pur-chase StrataCom.Ciscos’s Internet Operating System(IOS)is a platform that came to dominate the network industry in the 1990s.StrataCom emerged as the leading provider of a small,but rapidly expanding,new transmission technology,Asynchronous Transmission Mode(ATM).The question for Cisco and Strata-Com was whether to coordinate their technologies.Initially they tried to do this as separatefirms,but apparently this did not work out.Cisco then acquired StrataCom.5Each unit has a binary decision:it can choose“Yes”or“No.”Moreover,we simplify matters further by supposing that there are only two aggregate outcomes,which we term“coordination”or“noncoordination.”Coordination occurs if and only if both units choose Yes.That is,each party can veto coordination by choosing No.The decision in each unit is ex ante noncontractible,but ex post contractible.Each unit has a boss.The boss has the right to make the decision in that unit ex post;that is,the boss has residual control rights.In the simplest version of our model the boss is equivalent to an owner;however,in extensions,the boss and owner can be different.We will compare two leading organi-zational forms.In thefirst,nonintegration,the units are separate firms,and the unit managers are the bosses.In this case the unit managers make the Yes/No decisions.In the second,integration,4.For a discussion,see Hart(2008).5.There is thus a parallel between Cisco–StrataCom and the famous case of General Motors and Fisher Body.General Motors and Fisher Body initially transacted as separatefirms,but General Motors then acquired Fisher Body.See, for example,Klein(2007).486QUARTERLY JOURNAL OF ECONOMICSthe units are part of a singlefirm,and an outside manager is the boss.In this case the boss instructs the managers whether to choose Yes or No,and the managers must follow these instruc-tions(they are contractible);however,the managers may shade on performance.6A key ingredient in our model is the assumption that each unit generates two kinds of benefit:monetary profit,which is transferable with ownership,and private benefits,which are nontransferable.Private benefits represent job satisfaction, broadly defined.They may arise from various sources.Employ-ees often have their human capital tied to particular technologies. They like to work with technologies with which they are familiar. If a new technology is introduced the employees need to learn new skills,which is costly.Also,the future wages and career prospects of employees may depend on how well their human capitalfits the firm’s needs:thefirm’s choices will therefore affect them.In sum, employees care about the decisions of thefirm they work for.The evidence that smaller companies pay less on average than larger companies(see,e.g.,Schoar[2002]on pay in conglomerate versus stand-alone plants)is consistent with the idea that employees are affected by the size and scope of their companies.Private benefits can also be viewed as a way of capturing different beliefs held by managers and workers about the conse-quences of strategic choices(for an explicit analysis of differences in beliefs with organizational implications,see Van den Steen [2005]).In high-tech industries,different visions about the future path of particular technologies are held with passion and influ-ence both the costs of hiring and the decisions undertaken.Our discussion of the Cisco case suggests that private benefits were very important to Cisco and influenced its decision making.The role of the two types of benefits in our analysis can be illustrated as follows.Denote the pair of profits and private ben-efits(measured in money)accruing to each unit by(v A,w A)and (v B,w B),respectively.To simplify the analysis,assume that themanager is the only worker and hence private benefits refer to his job satisfaction.7As well,assume that the boss of a unit can use her residual rights of control to divert all the profit from that6.These are not the only possibilities.For example,one could consider another form of integration where one of the unit managers is the boss.We discuss this in Section III.7.The interpretation that private benefits are enjoyed by a single manager is restrictive.In the Conclusions we discuss briefly the case where the units are large companies,and private benefits refer to the aggregate job satisfaction of workers.A THEORY OF FIRM SCOPE487 unit to herself.This rules out profit sharing as a way to influence incentives.Profit sharing would alleviate,but not eliminate,the effects we describe.8If the units are nonintegrated,manager A is the boss of unit A,and managerB the boss of unit B;manager A’s payoff will be v A+w A,because he diverts the profit from unit Aand cares about his own private benefits,and manager B’s payoff will be v B+w B,for similar reasons.In contrast,if units A and B are integrated,then,if a(professional)outsider is the boss,her payoff will be v A+v B,because she diverts all the profit and does not care about private benefits.As a benchmark,note that social surplus is given by v A+v B+w A+w B.The key point is that integration results in less weight being placed on private benefits than under nonintegration.Under non-integration,w A,w B each appears in one boss’s objective function. In contrast,under integration the w’s fail to appear in the overall objective function.However,this diminished influence of private benefits is offset by the fact that,under integration,total profits, rather than individual unit profits,are maximized.The actual analysis is more complicated because the dead-weight losses from shading must be taken into account.Shad-ing causes some internalization of externalities:a boss puts some weight on the payoffs of other parties,given their ability to shade.We assume that the opportunity to shade under noninte-gration also depends on the nature of the relationship between the parties.We make a distinction between two forms of non-integration.In one,“nonintegration without cooperation,”the relationship between the units is a limited one that terminates if noncoordination occurs;the units cannot shade against each other in this eventuality.In the other,“nonintegration with coopera-tion,”the relationship persists;shading can occur under noncoor-dination.In contrast,we assume that shading is always possible under integration:the parties continue to have a relationship.In summary,under nonintegration,bosses have the right bal-ance between private benefits and profits,but are parochial(they do not take into account their effect on the other unit),whereas, under integration,they have the right balance between units, but ignore private benefits.In our model,where the only issue is whether the units coordinate,we show that nonintegration and integration make opposite kinds of mistakes.Nonintegration can lead to too little coordination when the benefits from coordination8.We return to this issue briefly in Section V.488QUARTERLY JOURNAL OF ECONOMICSare unevenly divided across the units.One unit may then veto coordination even though it is collectively beneficial.In contrast, under a weak assumption—specifically,that coordination repre-sents a reduction in“independence”and therefore causes a fall in private benefits—integration leads to too much coordination.9,10 We analyze the above model in Sections II and III.In Section IV,we generalize the model to allow delegation of decision-making authority under integration.We argue that it is hard to make sense of delegation in much of the literature,because it is unclear why the boss cannot change her mind ex post and take back the decision rights that she has delegated.The presence of aggrievement can help here.We assume that reversing delega-tion is regarded by subordinates as a“breach of promise”and leads to increased levels of aggrievement.This makes delegation a credible commitment device:the boss will reverse herself only in“extreme”states of the world.We show that integration with delegation can be a valuable intermediate organizational form between nonintegration and integration.Under delegation,man-agers get their way in states of the world where decisions matter significantly more to them than to the boss.However,in states of the world where the boss cares a lot about the outcome,either managers will do what the boss wants of their own accord,given the threat of shading by the boss,or the boss will take back the decision rights.Our paper is related to a number of ideas that have appeared in the literature.First,there is an overlap with the literature on internal capital markets;see particularly Stein(1997,2002), Rajan,Servaes,and Zingales(2000),Scharfstein and Stein(2000), Brusco and Panunzi(2005),and Inderst and Laux(2005).This9.In our model the boss of an integratedfirm has relatively broad objectives because he diverts(all of)the profit from the units under his control.We believe that a boss may have broad objectives for other reasons:he may be judged according to how well the units under his control perform,or obtain job satisfaction from their success.10.In a previous version of the paper we assumed that decisions were non-contractible both ex ante and ex post,and did not adopt the“contracts as reference points”approach.We obtained a similar trade-off between nonintegration and in-tegration,but our approach raised some questions.(In independent work,Baker, Gibbons,and Murphy[2008]also obtain a trade-off similar to ours under the as-sumption that decisions are ex post noncontractible.)First,if a decision is ex post noncontractible,how does a boss get it carried out except by doing it herself?Sec-ond,even if decisions are ex post noncontractible,as long as decision rights can be traded ex post,it is unclear why ex ante organizational form matters(in the absence of noncontractible investments).The parties could just rely on ex post bargaining of decision rights to achieve an optimum.Finally,the“ex post noncontractibility”approach by itself does not yield an analysis of delegation(see below).A THEORY OF FIRM SCOPE489 literature emphasizes the idea that the boss of a conglomerate firm,even if she is an empire builder,is interested in the overall profit of the conglomerate,rather than the profits of any partic-ular division.As a result,the conglomerate boss will do a good job of allocating capital to the most profitable project(“winner-picking”).Our idea that the professional boss of an integrated firm maximizes total profit is similar to this;the main differences are that the internal capital markets literature does not stress the same cost of integration as we do—the boss’s insufficient em-phasis on private benefits—or allow for the possibility that the allocation of capital can be done through the market(in our model, the market is always an alternative to centralized decision mak-ing),or consider standard-setting.Second,the idea that it may be efficient for thefirm to have narrow scope and/or choose a boss who is biased toward particular workers is familiar from the work of Shleifer and Summers(1988),Rotemberg and Saloner(1994, 2000),and Van den Steen(2005).These papers emphasize the effect of narrow scope and bias on worker incentives rather than on private benefits or wages,but the underlying premise,that workers care about the boss’s preferences,is the same.However, none of these papers analyzesfirm boundaries.Third,several recent works explorefirm boundaries and internal organization using the idea that some actions are noncontractible ex ante and ex post but may be transferable through ownership;see,for ex-ample,Holmstrom(1999),Aghion,Dewatripont,and Rey(2004), Mailath,Nocke,and Postlewaite(2004),Bolton and Dewatripont (2005),Hart and Moore(2005),Alonso,Dessein,and Matouschek (2008),Baker,Gibbons,and Murphy(2008),and Rantakari(2008). We discuss in footnote10some reasons that we have not followed the“ex post noncontractibility”approach here.We should point out how our analysis of delegation differs from the treatment of authority in Aghion and Tirole(1997)(see also Baker,Gibbbons,and Murphy[1999]).In Aghion and Tirole, a boss defers to a subordinate in situations where the subordinate has superior information.In this case,even though the boss has “formal”authority,the subordinate has“real”authority.In con-trast,we are interested in situations where allocating authority to someone inside afirm has meaning.As Baker,Gibbons,and Murphy(1999)point out,this corresponds to real rather than for-mal authority:if the boss appoints someone as unit head,say, she can legally change her mind and take the authority back. In our model,allocating authority inside afirm nonetheless has490QUARTERLY JOURNAL OF ECONOMICSform chosen made realizedF IGURE Imeaning.The reason is that there is a friction:designating some-one as unit head and then reversing the decision is costly,given that reversal increases aggrievement(by the unit manager,and possibly by unit workers to the extent that the new boss’s prefer-ences are less aligned with theirs).11The paper is organized as follows.The basic model is pre-sented in Sections II and III.In Section IV we analyze delegation. Section V illustrates the model using Cisco’s approach to platform leadership through acquisitions.Finally,Section VI concludes.II.A B ASIC M ODEL OF C OORDINATIONOur model concerns two units,A and B,that have a lateral relationship:they operate in the same output or input markets.A unit has a manager and no workers.Each unit makes a decision that affects the other unit.For example,the units may be decid-ing whether to adopt a common standard or platform for their technology or products.It is natural to model such a strategic co-ordination decision as a binary choice.Each unit can choose“Yes”(Y)or“No”(N).There are two aggregate outcomes:“coordination”or“noncoordination.”Coordination occurs if and only if both units choose Y.The timeline is as in Figure I.At the beginning,an orga-nizational form is selected—specifically,whether the units should be separatefirms(nonintegration,i.e.,there are two bosses)or should merge into onefirm(integration,i.e.,there is one boss). Next,each unit chooses Y or N.Finally,the payoffs are realized.Each unit generates two kinds of benefit:monetary profit v and private(nontransferable)benefits w in the form of job sat-isfaction for the manager working in the unit(private benefits are measured in money).We assume that the boss of the unit can divert all the profit from that unit to herself.12In contrast, the private benefits always reside with the managers.We repre-sent payoffs from different outcomes in the matrix in Table I.We assume that these payoffs are nonverifiable and,for simplicity,11.In Baker,Gibbons,and Murphy(1999),reversal is also costly given that it is a breach of a relational contract.12.One justification is that the boss can use her residual control rights to authorize side-deals with other companies she owns,and this enables her to siphon profit out of the unit.A THEORY OF FIRM SCOPE491TABLE IP AYOFFSUnit BY NY A: v A, w A A:0,0Unit A B: v B, w B B:0,0N A:0,0A:0,0B:0,0B:0,0perfectly certain.Without loss of generality we normalize so that monetary profit and private benefits under noncoordination are zero in both units.Unit A is the row player,and unit B is the col-umn player.Subscripts refer to units,with v representing profit and w private benefits.It will be convenient to introduce the notation(1)z A≡ v A+ w A, z B≡ v B+ w B.Here, z A(resp. z B)refers to the change in total surplus in unit A (resp.unit B)from coordination,and z A+ z B equals the change in aggregate social surplus.Note that(1)does not account for the costs of aggrievement,which depend on the ex ante contract as well as the ex post decision.As discussed in the Introduction,private benefits refer (broadly)to job satisfaction or on-the-job consumption.It is rea-sonable to assume that part of job satisfaction stems from the ability to pursue an independent course or agenda.Thus,we will assume that coordination leads to a reduction in private benefits:w A≤0, w B≤0.13(2)We put no restrictions on whether coordination increases or decreases profits;moreover,even if coordination increases total profits,profits may rise by more or less than the fall in private benefits.We will focus on two leading organizational forms:1.Nonintegration:14Manager A is the boss of unit A andmanager B is the boss of unit B.Each manager diverts.13.Our main results generalize to the case w A+ w B≤0.We make the stronger assumption(2)for expositional simplicity.14.We will actually consider two subcases of nonintegration,one without cooperation and one with cooperation,as discussed below.492QUARTERLY JOURNAL OF ECONOMICSprofit and receives private benefits from his unit,and somanager A’s payoff is v A+w A,and manager B’s is v B+w B.2.Integration:A professional manager(an outsider)is theboss of both units and managers A and B are subordi-nates.The boss receives v A+v B.The unit managers areunderfixed-wage employment contracts and each man-ager receives the sum of the wage and private benefit inhis unit.Organizational form and contracts are determined ex ante.We will assume,as in the standard incomplete contracts literature, that at this stage the coordination decisions are too complicated to specify;however,authority over these decisions can be allocated. We will take the view that the boss of each unit has residual rights of control,which gives her the legal authority to make the Y/N decisions in her unit.Ex post the Y/N decisions can be contracted on.Under nonintegration each unit manager chooses Y or N in his unit.Under integration,the overall boss instructs the unit managers to choose Y or N.We will assume that the unit managers must follow these instructions—they are contractible—but the managers may choose to shade.15Shading may also occur under nonintegration.As discussed in the Introduction,we use the“contracts as ref-erence points”approach of Hart and Moore(2008)to justify the particular contracting assumptions that we make.According to this approach a contract—an organizational form in this case—negotiated under ex ante competitive conditions delineates or cir-cumscribes parties’feelings of entitlement ex post.In particular, a contracting party does not feel entitled to an outcome outside those specified by the contract or organizational form.However, parties may feel entitled to different outcomes within the contract or organizational form.A party who does not receive what he feels entitled to is aggrieved and shades on performance.We assume that shading reduces the payoff of the shaded against party but does not affect the payoff of the party doing the shading.Shading creates deadweight losses.16Specifically,following Hart and Moore(2008),we assume that each party feels entitled to his most preferred outcome or decision within the contract,and that a party who receives k i less than his15.We do not allow managers to quit within a period;see footnote22.16.The reference points approach resembles in some respects relational con-tracting(see,e.g.,Baker,Gibbons,and Murphy[2008]).Shading is like punishment in relational contracting models,but shading does not hurt the person doing the shading.maximum payoff will be aggrieved by k i and will shade to the point where the other parties’payoffs fall by θk i .Here θis an exogenous shading parameter,assumed to be the same for all parties,and 0<θ<1.Thus the total deadweight loss from shading is θ i k i .The assumption that contracts are reference points provides a natural reason for parties to pin things down in an initial contract.A contract that is too flexible,that is,that specifies too little,can lead to a lot of aggrievement and shading ex post.The downside of a rigid contract is that it is harder for the parties to adjust to new circumstances.Even though there is no payoff uncertainty in our model,our assumption that decisions become contractible only ex post implies a change in circumstances that makes the ex ante choice of organizational form relevant for the deadweight losses from aggrievement,as will become clear below .There is a further consideration about shading:the ability of a party to shade may depend on the nature of the transaction that the party is engaged in.For example,under nonintegration,if the units fail to coordinate on a standard or platform,they may no longer have dealings with each other,which will reduce shad-ing possibilities.For this reason,we will distinguish between two forms of nonintegration.In one,“nonintegration without coopera-tion,”the parties’relationship ends in the absence of adoption of a standard and so shading is not possible under noncoordination.In the second,“nonintegration with cooperation,”the parties have a broader relationship that continues beyond the standardization decision and so shading is possible even under noncoordination.In contrast,under integration,we assume that shading is always possible:the parties continue to have a relationship.17Under the shading assumption,ex post renegotiation is not costless because each party will feel entitled to the best possible outcome in the renegotiation,and they cannot all be satisfied and will shade.Moreover,to the extent that renegotiation reopens consideration of the terms and entitlements underlying existing contracts,renegotiation can make all parties worse off.In the analysis below ,we will rule out ex post renegotiation on these grounds.However,we believe that our results could be generalized to ex post renegotiation along the lines of Hart (2009).We assume that bargaining at the ex ante stage ensures that organizational form is chosen to maximize expected future sur-plus net of ex post shading costs (lump sum transfers are used to17.In our discussion of the Cisco–StrataCom relationship in Section V we suggest that,before StrataCom was aquired,their relationship was probably best described as “nonintegration with cooperation.”。
F化学
Mild Copper-Mediated Fluorination of Aryl Stannanes and Aryl Tri fluoroboratesYingda Ye and Melanie S.Sanford *Department of Chemistry,University of Michigan,930North University Avenue,Ann Arbor,Michigan 48109,United States*Supporting Information ryl fluorides are extremely important structural motifs that feature prominently in pharmaceuticals,agrochemicals,organic materials,and biological imaging agents.1As a result,signi ficant recent e ffort has focused on the development of new synthetic procedures for the generation of C Aryl −F bonds.2Transition metal-mediated and/or catalyzed aryl −fluoride coupling reactions are of particular interest,because the rate,selectivity,and functional group tolerance of these trans-formations can often be modulated by changing the metal and its ligand environment.3Over the past 6years,several di fferent palladium 4and silver-based protocols have been developed to e ffect aryl −fluoride bond formation via cross-coupling with aryl C −H bonds,5,6aryl tri flates,7aryl stannanes,8aryl boronic acids,9and aryl silanes.10In several cases,these methods have been successfully applied to the late-stage fluorination of complex molecules.However,despite these signi ficant advances,the reactions generally remain limited by the requirement for expensive and toxic noble metals.A key unmet need in the field is a mild and general aryl fluorination protocol mediated by an earth abundant first row metal such as Cu.11In a seminal report in 2011,Ribas and co-workers demonstrated a proof-of-concept example of aryl −F bond formation at a macrocyclic aryl −Cu(III)complex.12,13More recently,Fier and Hartwig reported the Cu-mediated conversion of a broader scope of aryl iodides to aryl fluorides using AgF as the fluoride source at 140°C.14As shown in Scheme 1a,this transformation is also believed to proceed via a Cu III (aryl)(fluoride)intermediate A formed by oxidative addition of Ar −I to Cu(I)and subsequent reaction with AgF.Inspired by these exciting advances,we sought to develop a milder and more versatile Cu(III)-mediated aromatic fluorina-tion protocol.We hypothesized that an intermediate analogous to A could be formed under less forcing conditions via the combination of an electrophilic fluorinating reagent (F +)and an aryl organometallic species (Scheme 1b).5,15,16Importantly,literature precedent in Pd-and Ag-catalyzed fluorination reactions has shown that F +reagents can serve as fluorinesources without introducing extra ligands that might lead to unproductive competing reductive elimination from the metal center.4−6,8−10To test this hypothesis,we initially explored the Cu-mediated fluorination of aryl stannane 1with commercial electrophilic fluorinating reagents.These studies revealed that the combination of 1,(t BuCN)2CuOTf,and N -fluoro-2,4,6-trimethylpyridinium tri flate (NFTPT)in EtOAc at 25°C for 12h a fforded modest (6%)yield of the desired product 1a (Scheme 2a;see Tables S1−S4for full optimization details).The major byproduct of this transformation is biaryl 1b derived from unproductive homocoupling of the aryl stannane.We reasoned that its formation could be circumvented by initial oxidation of (t BuCN)2CuOTf with NFTPT to form putative Cu(III)−F intermediate B (Scheme 1)followed by addition of the stannane 1.As shown in Scheme 2b,this sequential addition protocol resulted in dramatically improved yield of 1a (74%)along with <4%of 1b .Notably,the control reaction (in the absence of Cu)did not a fford a detectable quantity of 1a .We next applied this room temperature fluorination protocol to a variety of di fferent aryl stannanes.As shown in Scheme 3,aryl stannanes bearing electron-donating and withdrawing substituents underwent fluorination in good to excellent yields under these conditions.The presence of ortho -substituents was also well-tolerated.Notably,in all of the examples shown in Scheme 3,no fluorination products were detected in the absence of Cu (see Table S5for the results of these control experiments).With this proof of principle in hand,we next investigated replacing the aryl stannanes with less toxic aryl −boron reagents.Received:January 10,2013Published:March 13,2013Scheme 1.Strategies for Cu-Mediated Aryl −F CouplingA series of p -FC 6H 4BX n derivatives were examined under identical conditions to those in Scheme 3.As shown in Table 1,the aryl boron reagents generally a fforded low to modest yields under these conditions.In most cases,the major byproducts were either unreacted starting material or fluorobenzene from protodeboronation.17The best result (46%yield)was obtained with the aryl tri fluoroborate substrate (entry 5).Optimization of this reaction showed that changing the solvent to MeCN resulted in an improvement in the yield to 58%(entry 6;see Tables S6−S9for full optimization details).The substrate scope for the copper-mediated fluorination of aryl tri fluoroborates is shown in Scheme 4.Aryltri fluoroborates bearing electron-donating and electron-withdrawing substitu-ents reacted to generate the aryl −F products in good yields.Substrates containing ortho -substituents also underwent e fficient fluorination under these optimized conditions.This protocol is compatible with a variety of common functional groups.Substrates bearing aryl aldehydes,ketones,amides,and esters produced the aryl fluorides in good yields.Control reactions (without added Cu)were conducted for all of the substrates in Scheme 4.17As shown in Table S10,the electron de ficient aryl tri fluoroborates showed no background reaction under these conditions.Furthermore,only traces of background fluorination products (2−6%)were observed with the electron rich substrates p -MeOC 6H 4BF 3K,MesBF 3K,and naph-thlylBF 3K.In summary,this communication describes a new method for the Cu-mediated fluorination of aryl stannanes and aryl tri fluoroborates with an electrophilic fluorinating reagent.The reactions proceed under very mild conditions (in many cases at room temperature)and exhibit a broad substrate scope and functional group tolerance.18A Cu(I/III)mechanism is proposed with a Cu III (aryl)(fluoride)(A in Scheme 1)serving as a likely intermediate.19Importantly,this strategy takes advantage of the dual role of the electrophilic fluorinating reagent as both an oxidant for Cu(I)and a fluorine source.20Ongoing work is focused on e ffecting analogous fluorination reactions using alternative oxidants in conjunction with nucleophilic fluoride sources.4a,e,21Scheme 2.Cu-Mediated Fluorination of Aryl StannanesScheme 3.Substrate Scope for Cu-Mediated Fluorination of Aryl Stannanes aaGeneral conditions:stannane (0.25mmol,1equiv),(t BuCN)2CuOTf (1equiv),NFTPT (2equiv),EtOAc (0.1M in stannane),25°C,12h.Copper salt and NFTPT were prestirred in solvent for 5min,followed by addition of the stannane.b Yield determined by 19F NMR spectroscopy.c Isolated yield.d Isolated product contained 8%of biphenyl (derived from protodestannylation).e 1.2equiv of (t BuCN)2CuOTf.Table 1.Cu-Mediated Fluorination of Aryl Boron Reagents aaGeneral conditions:stannane (0.025mmol,1equiv),(tBuCN)2CuOTf (1equiv),NFTPT (2equiv),EtOAc (0.1M in boron reagent),25°C,12h.Copper salt and NFPTP were prestirred in solvent for 5min,followed by addition of the substrate.Yields determined by 19F NMR spectroscopy.b Reaction conducted using MeCN as solvent.■ASSOCIATED CONTENT*S Supporting Information Experimental details and spectroscopic and analytical data for new compounds.This material is available free of charge via the Internet at .■AUTHOR INFORMATIONCorresponding Authormssanfor@NotesThe authors declare no competing financial interest.■ACKNOWLEDGMENTSWe thank the Dow Chemical Company for financial support.We thank Dr.Douglas Bland and Dr.Gary Roth from Dow Chemical for helpful discussions.REFERENCES(1)(a)Jeschke,P.Pest Manage.Sci.2010,66,10.(b)Purser,S.;Moore,P.R.;Swallow,S.;Gouverneur,V.Chem.Soc.Rev.2008,37,320.(c)Hagmann,W.K.J.Med.Chem.2008,51,4359.(d)Jeschke,P.ChemBioChem 2004,5,570.(2)(a)Balz,G.;Schiemann,G.Ber.Dtsch.Chem.Ges.1927,60,1186.(b)Barnette,W.E.J.Am.Chem.Soc.1984,106,452.(c)Differring,E.;Wehrli,M.Tetrahedron Lett.1991,32,3819.(d)Yamada,S.;Gavryushin,A.;Knochel,P.Angew.Chem.,Int.Ed.2010,49,2215.(e)Anbarasan,P.;Neumann,H.;Beller,M.Angew.Chem.,Int.Ed.2010,49,2219.(3)(a)Hollingworth,C.;Gouverneur,mun.2012,48,2929.(b)Furuya,T.;Kamlet,A.S.;Ritter,T.Nature 2011,473,470.(c)Grushin,V.V.Acc.Chem.Res.2010,43,160.(d)Brown,J.M.;Gouverneur,V.Angew.Chem.,Int.Ed.2009,48,8610.(4)For examples of C −F bond formation from Pd(IV)(R)(F)complexes,see:(a)McMurtrey,K.B.;Racowski,J.M.;Sanford,.Lett.2012,14,4094.(b)Racowski,J.M.;Kampf,J.W.;Sanford,M.S.Angew.Chem.,Int.Ed.2012,51,3414.(c)Ball,N.D.;Kampf,J.W.;Sanford,M.S.J.Am.Chem.Soc.2010,132,2878.(d)Furuya,T.;Benitez,D.;Tkatchouk,E.;Strom,A.E.;Tang,P.;Goddard,W.A.;Ritter,T.J.Am.Chem.Soc.2010,132,3793.(e)Lee,E.;Kamlet,A.S.;Powers,D.C.;Neumann,C.N.;Boursalian,G.B.;Furuya,T.;Choi,D.C.;Hooker,J.M.;Ritter,T.Science 2011,334,639.(5)Hull,K.L.;Anani,W.Q.;Sanford,M.S.J.Am.Chem.Soc.2006,128,7134.(6)(a)Chan,C.S.L.;Wasa,M.;Wang,X.;Yu,J.-Q.Angew.Chem.,Int.Ed.2011,50,9081.(b)Wang,X.;Mei,T.S.;Yu,J.-Q.J.Am.Chem.Soc.2009,131,7520.(7)(a)Maimone,T.J.;Milner,P.J.;Kinzel,T.;Zhang,Y.;Takase,M.K.;Buchwald,S.L.J.Am.Chem.Soc.2011,133,18106.(b)Noel,T.;Maimone,T.J.;Buchwald,S.L.Angew.Chem.,Int.Ed.2011,50,8900.(c)Watson,D.A.;Su,M.;Teverovskiy,G.;Zhang,Y.;Garcia-Fortanet,J.;Kinzel,T.;Buchwald,S.L.Science 2009,321,1661.(8)(a)Tang,P.;Furuya,T.;Ritter,T.J.Am.Chem.Soc.2010,132,12150.(b)Furuya,T.;Strom,A.E.;Ritter,T.J.Am.Chem.Soc.2009,131,1662.(9)(a)Furuya,T.;Ritter,.Lett.2009,11,2860.(b)Furuya,T.;Kaiser,H.M.;Ritter,T.Angew.Chem.,Int.Ed.2008,47,5993.(10)Tang,P.;Ritter,T.Tetrahedron 2011,67,4449.(11)For an example of fluorination of haloarenes by CuF 2/TMEDA,see:Grushin,V.Process for Preparing Fluoroarenes from Haloarenes.U.S.Patent 7,202,388,2007.(12)Casitas,A.;Canta,M.;Sola,M.;Costas,M.;Ribas,X.J.Am.Chem.Soc.2011,133,19386.(13)Yao,B.;Wang,Z.-L.;Zhang,H.;Wang,D.-X.;Zhao,L.;Wang,.Chem.2012,77,3336.(14)Fier,P.S.;Hartwig,J.F.J.Am.Chem.Soc.2012,134,10795.(15)While this manuscript was under review,a closedly related transformation was reported by Hartwig and co-workers:Fier,P.S.;Luo,J.;Hartwig,J.F.J.Am.Chem.Soc.2013,135,2552.(16)Engle,K.M.;Mei,T.-S.;Wang,X.;Yu,J.-Q.Angew.Chem.,Int.Ed.2011,50,1478.(17)For metal-free electrophilic fluorination of electron rich aryl tri fluoroborates by F-TEDA-BF 4,see:Cazorla, C.;Metay, E.;Andrioletti,B.;Lemaire,M.Tetrahedron Lett.2009,50,3936.(18)Inert atmosphere and dry reagents are required for all the reactions in Schemes 3and 4.Reactions conducted in air with nondried reagents showed signi ficantly reduced yields.See Supporting Information for more details.(19)19F NMR analysis of the reaction of (t BuCN)2CuOTf with NFTPT in EtOAc at room temperature shows a resonance at −123.0ppm,which may correspond to a Cu(III)−F;however,this species is formed in low yield (∼1%),so it is unclear whether it is responsible for the observed reactivity.When this same reaction was conducted in the presence of 10equiv of THF,the Cu(III)complex recently characterized by Hartwig [ref 15]was detected by 19F NMR spectroscopy,albeit also in modest (∼18%)yield.See Supporting Information for relevant spectra.Ongoing e fforts are focused onScheme 4.Substrate Scope for Cu-Mediated Fluorination of Aryl Tri fluoroborates aaGeneral conditions:substrate (0.25mmol,1equiv),(tBuCN)2CuOTf or (MeCN)4CuBF 4(1to 2equiv),NFTPT (2equiv),40or 80°C,12h.Copper salt and NFTPT were prestirred in solvent for 5min,followed by addition of the substrate.b Yield determined by 19F NMR spectroscopy.c Isolated yield.d Isolated products contained small amounts (4−6%)of inseparable proto-deboronated side-products.gaining further insights into the organometallic intermediates and the mechanistic complexities of this transformation.(20)Yin,F.;Wang,Z.;Li,Z.;Li,C.J.Am.Chem.Soc.2012,134,10401.(21)For a related approach to Ni-and Pd-mediated fluorination,see:Lee,E.;Hooker,J.M.;Ritter,T.J.Am.Chem.Soc.2012,134,17456.。
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Interest Rates and the Durability of ConsumptionGoodsHarry Mamaysky∗This Draft:March11,2001Comments Welcome∗Yale School of Management,135Prospect St.,Box208200,New Haven,CT,06520-8200.Email: harry.mamaysky@.Phone:(203)436-0649.Fax:(203)436-0630.I would like to thank Hua He, Jonathan Ingersoll,Andrew Jeffrey,Leonid Kogan,Geert Rouwenhorst,Matthew Spiegel,and Raman Uppal for very helpful discussions.Interest Rates and the Durability of ConsumptionGoodsAbstractIn this article I study an economy with irreversible durable investment and investors who consume a durable and a nondurable good.In equilibrium,these assumptions lead to endoge-nous variation in the implied risk aversion of investors.This in turn causes the short term interest rate,the exchange rate between the two goods,and the term structure of interest rates tofluctuate stochastically.I investigate the connection between thesefinancial vari-ables and investment into the durable good,and provide one explanation for several features of the empirical relationship between interest rates and the business cycle.Additionally,I derive a closed form asymptotically valid solution of the model.Using U.S.GNP and government bond data,I test several implications of the model.As predicted by the model,Ifind that the fraction of GNP devoted to durable consumption is (1)procyclical,(2)able to forecast future GNP growth,(3)able to forecast the future term spread,and(4)able to forecast future excess returns on long term bonds.The model and the data suggest that a fundamental link exists between durable consumption and interest rates.JEL Classification:G12Contents1Introduction1 2The Model72.1A Pareto Optimal Allocation (8)2.2Discussion of the Model (9)3The Equilibrium103.1An Agent’s Control Problem (10)3.2The Optimal Investment Policy (13)3.3The Price of Durable Goods (14)3.4The Short Rate and Bond Prices (16)4Separating Durable and Nondurable Consumption18 5Analysis of the General Case215.1Nondurable Consumption (21)5.2Risk Aversion (23)5.3The Behavior of K t/z t (25)5.4The Price of Durable Goods (28)5.5The Short Rate (30)5.6The Term Structure of Interest Rates (33)6Interest Rates and the Business Cycle356.1A Review of Some Empirical Findings (35)6.2The Term Spread and the Business Cycle (37)6.3The Short Rate and the Business Cycle (40)6.4The Nondurables to Durables Ratio and the Business Cycle (42)7Empirical Results427.1Data Description (43)7.2D/GNP and GNP Growth (44)7.3The Term Spread and D/GNP (47)7.4Forecasting Bond Returns (51)8Conclusion52 9Appendix559.1Lemmas5and6 (55)9.2Proof of Theorem1 (56)9.3Proof of Theorem2 (60)9.4Proof of Theorem3 (61)9.5Perturbation Analysis (61)9.6Proof of Lemma1 (63)9.7Proof of Lemma2 (64)9.8Proof of Lemma4 (64)References661IntroductionConsumption goods vary dramatically in their degrees of durability.For example,going to a movie results in relatively short-lived enjoyment,whereas purchasing a VCR will likely provide a longer lastingflow of service.Recognizing such distinctions,the U.S.Department of Commerce classifies consumption goods as either durables or nondurables.In2000,durable and nodurable goods consumption respectively accounted for roughly12%and60%of U.S. GNP.1The asset pricing literature has long recognized that consumption patterns of investors have important implications for the prices offinancial securities(see Lucas(1978),Mer-ton(1973,1990),Cox,Ingersoll,and Ross(1985a,b),Cox and Huang(1989),and Breeden (1979)).Breeden(1979)shows that when identical investors consume a single,short lived(or nondurable)good the expected returns onfinancial assets depend on their covariance with the growth rate of aggregate consumption.However,subsequent empirical work has shown that this model fails to satisfactorily account for important features of the actual relation-ship between consumption and asset returns(see Hansen and Singleton(1983),Campbell (1999),and Campbell and Cochrane(2000)).Accordingly,later research has focused on ex-tending the traditional framework to incorporate more realistic assumptions about people’s preferences over consumption goods.One line of the literature considers the effects of habit formation on investor behavior and on asset prices(see Constantinides(1990)and Abel(1990)).The habit formation paradigm has had some success in explaining the moments of actual returns data(see Campbell and Cochrane(1999)).Another strand of research considers utility functions where the degree of risk aversion is not linked to the elasticity of intertemporal substitution(Epstein and Zin (1989,1991)).Heaton(1993,1995)provides evidence that durability of consumption goods is important in explaining aggregate consumption data.Hindy and Huang(1993),Grossman and Laroque(1990),and Cuoco and Liu(2000)are theoretical studies of investors who consume a durable,rather than a nondurable,good.Hindy,Huang,and Zhu(1997)extend this framework to take into account habit formation over the level of durable consumption.1Based on the February28,2001Gross Domestic Product estimates available from the U.S.Department of Commerce().Durable goods consumption consists of personal consumption expenditure on durable goods plus gross private domestic investment in residential real estate.Nondurables consumption includes personal consumption expenditure on nondurables and services.Surprisingly,however,there has been relatively little work done on the asset pricing implications of investors who consume goods with different degrees of durability.For this purpose,the ideal model is one where agents consume an arbitrary number of goods,each of which has a different lifetime of usefulness.However,this situation is prohibitively difficult to handle.To capture the qualitative aspects of the investment and consumption decision with multiple durability of goods,I will focus on investors who consume only two goods:a short lived good and a long lived good.The economy that I consider works as follows.Imagine a farmer who grows bamboo.To him,bamboo has three possible uses.First,it may be consumed for immediate satisfaction, hence its role as the nondurable good.Second,bamboo may be replanted.This will produce bamboo in the future.Third,the farmer may use bamboo to build additions to or to repair his house.The house is the durable good.Notice,however,that once bamboo has been used in the construction of the house,it will be impossible either to consume or replant it in the future.This irreversibility of investment plays an important role in the ensuing analysis. Now consider an economy that consists of many,identical such farmers.They are able to lend bamboo to one another,as well as to sell parts of their homes on a spot market(you can imagine they can sell part of a wall that another farmer may use in his own house).I will study the behavior of interest rates and of durable goods prices(or house parts prices) in this economy.In this respect,this paper is closely related to Detemple and Giannikos(1996),who consider investors who consume nondurable and durable goods.In their model agents derive “status”from their durable goods purchases.This makes the irreversibility constraint faced by these investors non-binding.In a setting similar to the one in this paper,Damgaard, Fuglsbjerg,and Munk(2000)study the control problem of an investor who consumes durables and nondurables.However they do not consider the asset pricing implications of durable and nondurable consumption.Dunn and Singleton(1986)look at an economy where agents consume durable and nondurable goods,but where durable investment is reversible.They estimate their model using U.S.bond data and reject the model as an explanation for these data.However,it is possible that the rejection is due to the fact that durable investment in their model is reversible.Finally,this paper is related to the Hindy,Huang,and Zhu(1997) paper in which investors consume a durable good and form a habit over past durable goodconsumption.In my model,consumption of the nondurable good plays the role of the habit in their model.2The contributions of this paper are both methodological and positive in nature.On the methodological side,the paper formulates and solves a general equilibrium production economy where agents care about durable and nondurable good consumption,and where durable investment is irreversible.Asset prices in this framework and an approximate closed form solution of the model are derived.On the positive side,the paper illustrates that taken together,its preference and irre-versibility assumptions effect time-varying risk aversion and interest rates.This time varia-tion is not due to an exogenously specified state variable.3Instead,it is shown that the ratio of aggregate nondurable holdings to the aggregate durable goods stock(derived endogenously from optimizing behavior of agents)fully characterizes the state of the economy.The paper establishes a connection between this ratio,investment activity,andfinancial variables(such as interest rates and the prices of durable goods).Agents in the model are assumed to have preferences over consumption given byU(c,z)=c A z B A+Bwhere c is the instantaneous nondurable good consumption,and z is the amount of service flow derived from an agent’s holdings of the durable good.Serviceflow from the durable is assumed to be directly proportional to the amount of durable good held.4Agents are able 2Dumas(1992)analyzes the exchange rate between two otherwise identical nondurable goods in spatially separated economies.The paper is similar to this one in that frictions exist for transfers between the capital stocks.The major difference is that both stocks in Dumas(1992)are of a nondurable consumption good. There is also an extensive and related literature on the investment decisions offirms.Kogan(2000)studies the stock prices of profit maximizingfirms which invest in a durable good in an economy where investors’preferences over durable and nondurable consumption are additive.Other related papers include Abel and Eberly(1996),Bertola and Caballero(1994),and Dixit(1991).There has also been a considerable amount of work in macroeconomics on the interaction of investment decisions and the business cycle.Rouwenhorst (1995)provides a discussion of how this literature is relevant to topics in asset pricing.3It is well known that in the Cox,Ingersoll,and Ross(1985a,b)representative agent economy,if the production opportunity set is constant,the short term interest rate turns out to be constant as well,implying that the term structure of interest rates isflat.A nontrivial term structure can be obtained in this setting by assuming exogenous variation in the production opportunity set.Two prominent models of the term structure which do not need to assume exogenous state variables are Dumas(1989)and Wang(1996).Both models look at an economy with two groups of agents who have different risk aversions inside the HARA class.Trade between these two sectors leads to endogenous variation in the short rate,and a time varying term structure of interest rates.This paper shows that endogenous variation in interest rates can be obtained by having heterogeneous consumption goods,rather than heterogeneous investors.4In fact,going forward,I will assume that the serviceflow is exactly equal to the durable stock.to invest their holdings of the nondurable good in a production technology with a constant investment opportunity set.Furthermore,at any time,they are able to transfer a unit of nondurable into a unit of the durable good.In order to qualitatively capture aggregate investment behavior,I assume that such transfers are irreversible.Once a unit of nondurable has been transferred into a unit of the durable good,the reverse transfer is technologically infeasible.The optimal consumption policy for the nondurable is to consume continuously at a rate c t.While the current durable stock provides a continuous serviceflow,new investment into the durable good occurs only periodically.Hence the economy goes through long periods of time when no new investment takes place.The implied risk aversionγof investors in this economy is given byγ≡µ−r σ2whereµandσare,respectively,the constant return and volatility of the production tech-nology,and where r is the endogenously determined short term interest rate.The above preference assumption,along with the irreversibility constraint,yield an economy where the implied risk aversion depends on the ratio of the nondurable to the durable goods.Therefore, the short term interest rate,the price of a unit of durable good,and the term structure all evolve stochastically as a function of this state variable.In the model,new investment into the durable good occurs when the short term interest rate is at its highest level.This result is in contrast to the traditional partial equilibrium analysis which suggests that new investment ought to occur when the cost of capital is lowest.The partial equilibrium analysis,however,ignores the value of new investment.The price(in units of the nondurable)of a new unit of the durable good is also highest when new investment takes place:both the numerator and the denominator of the net present value calculation are high,with the increase in the numerator being the dominant effect.By not endogenizing both the cost and the benefit of new investment,the traditional analysis appears to makeflawed predictions(see Taylor(1999)for a discussion of some relevant issues).New investment occurs when the nondurables to durables ratio is sufficiently high.There-fore,a link can be established between this ratio andfinancial variables.Specifically,the term spread(the difference between a long and a short yield)is shown to be decreasing inthe nondurables to durables ratio when the economy is close to the point of new investment. The nondurables to durables ratio is shown to have a positive contemporaneous correlation with the GNP to nondurable ratio,and to have predictive power for future GNP growth. The volatility of the short rate exhibits an inverted U-shape with respect to the nondurables to durables ratio.The volatility of the durable good price has a similar behavior,and is equal to zero at the point of investment.The model provides a potential economic explanation for several empirically observed relationships between interest rates and the business cycle.For example,Fama and French (1989)document that the term spread is countercyclical,while the short rate is procyclical. Harvey(1989)finds that the term spread is able to forecast future GNP growth.Plosser and Rouwenhorst(1991)find that the short rate also has forecasting power for growth in future output.The present model generates a term spread with a negative contemporaneous relationship with GNP,and a positive relationship with future GNP growth.Furthermore,the short rate is highest during high output periods,and is lowest during low output periods.The short rate is also shown to have predictive power for future growth in GNP.The model is therefore able to reproduce several salient features of the empirical data on interest rates and the business cycle.The underlying cause of these relationships is the irreversibility of aggregate investment in the durable good.Because of irreversibility,investment only happens after high output periods,thereby depressing the future growth rate of the productive capital (since nondurable holdings are being siphoned offinto the non-growing durable stock rather than being reinvested in the production technology).This causes periods of high output to be followed by periods of low output.The present model does not admit a closed form solution,and therefore is solved numeri-cally.Also an approximate closed form solution is derived using the method of perturbation analysis.This solution is asymptotically correct as agents’preferences move towards being only concerned with nondurable good consumption.In this limit,the model becomes the standard,constant interest rate Cox,Ingersoll,Ross(1985a,b)economy.The model predicts that the ratio of GNP devoted to durable goods consumption(D/GNP) is a proxy for the nondurables to durables ratio,which is the state variable in the economy. Because new durable investment is irreversible,investors will not transfer nondurables todurables unless the nondurable stock is sufficiently high.Hence the model predicts that D/GNP should be high following periods of high economic growth.Furthermore,the econ-omy tends to hover around the region where agents invest into the durable.This investment siphons productive capital away from the production technology,and into durable goods. Hence periods of high durable good investment ought to predict relatively low future output.A high value of D/GNP should therefore predict low output growth at some point in the future.The term spread in the model is low when new durable investment takes place.Hence D/GNP should be negatively correlated with the term spread.Also because of the persis-tence of new durable investment in the model,high durable investment should predict a low term spread in the future.Hence a high value of D/GNP should predict a low future term spread.Finally,because D/GNP should have predictive power for future term spreads,it should also have predictive power for future excess returns on long term bonds.These implications of the model are tested and confirmed using U.S.GNP and govern-ment bond data for the time period from1951–1999.The D/GNP ratio is shown to be high following periods of high growth in real GNP,and to have forecasting power for future growth in real GNP.Also D/GNP is able to predict the future term spread,and to have substantial explanatory power for future excess returns on long term government bonds.These connec-tions between a pure economic variable D/GNP and the term structure suggests that the durability of consumption goods,along with the irreversibility of durable good investment, play a fundamental role in the determination of interest rates.The rest of the paper proceeds as follows.Section2formulates the model.Section3 shows how the equilibrium asset prices in this economy are derived.Section4analyzes the two base cases of the present model:consumption of only durables or only nondurables. Section5analyzes the general case of the present model.Section6analyzes the relationship betweenfinancial variables and real economic activity in the model.Section7presents the empirical results.Section8concludes.All proofs and the perturbation analysis are shown in the Appendix.2The ModelThe underlying uncertainty of the economy is characterized by a1dimensional standard Brownian motion B={B t:t≥0}defined on itsfiltered probability space(Ω,F,F,P). Thefiltration F={F t:t≥0}represents the information revealed by B over time.The economy contains a nondurable good(the productive capital)and a durable good. The nondurable good acts as the numeraire.There is a production technology for the nondurable in the economy.This technology transforms units of nondurable today into units of nondurable tomorrow.Units of nondurable may also be transformed into units of the durable good.However,units of durable good may not be transformed back into the nondurable.Hence investment in the durable good is irreversible.The stock of durable good depreciates over time to reflect the effects of physical deterioration.The aggregate nondurable stock K t and the aggregate durable stock z t evolve according todK t=µKdt+σKdB t−c t dt−dΦt(1)dz t=−θz t dt+dΦt(2)Here c t is aggregate nondurable consumption,dΦt is the time t aggregate investment into the durable,andθis the durable depreciation rate.Hereµandσare constants which characterize the production opportunities available for the nondurable goode.We assume that c t satisfies the appropriate integrability condition.In(1–2),the stochastic processΦt is the cumulative amount of nondurable transfered into the durable good as of time t.Investment can occur either in infinitesimalflows or in lumps.5As will become clear,for the optimal policy,infinitesimal investment occurs when 5More formally(following Hindy and Huang(1993))let us define X+as the space of all processes x with paths that are positive,increasing,and right continuous.An increasing function x(·)has afinite left limit at any t,denoted by x(t−).The convention used in this paper is that x(0−)=0.A jump of x(·)atτisdenoted by∆x(τ)=x(τ)−x(τ−).We will assume thatΦt∈X+.For anyω∈Ωthe points of discontinuity ofΦ(ω,t)correspond to the times when agents transfer a non-infinitesimal amount of nondurable into the durable good.The transfer processΦt has an absolutely continuous component over those times when agents transfer nondurable into the durable at a rate of dΦ(ω,t)/dt per unit time.Furthermore,Φ(ω,t)may have a singular component.The context in which the singular process arises in the present setting is the following.Let B t be a standard Brownian motion on F,and let c be some constant.Define a process A t≡sup s≤t(B s−c)+.The process A t will be singularly continuous(as opposed to absolutely continuous)and will be referred to as a singular process.Notice that(i)A t is non-decreasing and therefore offinite variation,and(ii)the controlled Brownian motion B∗t≡B t−A t will always be less than or equal to c.it is necessary to keep the pair{K t,z t}inside a region of no-investment.An infinitesimal amount of nondurable will be transferred into the durable when the pair reaches the boundary of the region,and the transfer is only large enough so as to push the pair back into the region’s interior.Because the state variables in the model evolve in a continuous way,once the pair {K t,z t}is either on the boundary or inside of the no-investment region,it will remain inside this region.Lumpy investment can occur if at time0the pair{K0,z0}lies outside of the no-investment region.The lumpy control is then exerted to bring the pair to the boundary of the region.In what follows we assume,without loss of generality,that{K0,z0}is inside the no-investment region.Each unit of the durable good produces a consumption stream which is valuable to the agents in the model.Furthermore agents may consume out of their own nondurable stock. Agents’time t utility over consumption from the durable and nondurable good is given byU(c t,z t)=c A t z B tA+B,(3)where c t is the consumption rate from the nondurable,and z t is the serviceflow from z t units of the durable good.6It is assumed that(1)A>0,B>0and A+B<1,or(2) A<0,B<0.Agents maximize a utility of the formE0 ∞0e−ρt U(c t,z t)dt (4) The economy contains a continuum of competitive investors,all of whom have identical preferences given by(4).2.1A Pareto Optimal AllocationAll investors have identical utility functions,and start with identical ratios of nondurable to durable good holdings.That is,for every investor i,it is assumed that the ratio K i0/z i0is identical.To determine a Pareto optimal allocation in the economy,we can simply consider the control problem of a representative agent.7Agents’consumption and investment behavior depends only on their own ratios of nondurable to durable stock.If at the start of the6Alternately we can write the utility function as U(c t,z t)=1/β(cαt z1−αt)βwhereα=A/(A+B)andβ=A+B.7In the case where all investors have HARA utilities with the same risk aversion,Rubinstein(1974)showed that many such investors aggregate into a single,representative investor with the same utility function.economy,this ratio is the same for all investors,it will stay the same for all investors at all future times.Aggregation will hold regardless of the actual values of K i0.In order to characterize the equilibrium,it is sufficient to solve the following control problem.J(K,z,t)≡maxE0 ∞0e−ρt U(c t,z t)dt ,(5)c t,ΦtSuch that dK t=µKdt+σKdB t−c t dt−dΦt,(6)dz t=−θz t dt+dΦt,(7)K t>0z t>0dΦt≥0c t>0.(8) At the aggregate level,there is no investment in the locally riskless asset.This reflects the market clearing condition that all bonds are in zero net supply.We will later derive the interest rate that would induce agents to invest all of their nondurable capital in the risky production technology.The zero net supply of bonds condition will also allow us to derive the prices of bonds,and hence the term structure of interest rates,in this economy.2.2Discussion of the ModelThis model can be thought of as an extension of a simplified version of the Cox,Ingersoll, and Ross(1985a)model.In order to generate a non-trivial term structure in their model, the authors needed to assume an exogenous state variable.The obvious drawback of this approach is that an exogenously assumed source of uncertainty is difficult to interpret.Another related model is Hindy and Huang(1993).They assume that agents only have utility over durable consumption.Alternatively,one can interpret the preference structure in their case as allowing for local substitution of nondurable consumption.As in Cox,Ingersoll, and Ross(1985a),the Hindy and Huang model with a constant investment opportunity set will have constant implied risk aversion,and therefore,constant interest rates.In reality,of course,people consume both durable and nondurable goods.The current model explicitly accounts for such preferences.By assuming that aggregate investment into durable goods is irreversible(how does one disinvest from a bridge,for example),the present model endogenously obtains time varying implied risk aversion.Most importantly,this is done without having to assume an exogenous state variable.The consequence of time varyingimplied risk aversion is that the short rate is stochastic,and that the term structure becomes a non-trivial function of the state of the economy.Furthermore,by assuming nothing more than the basic economic primitives,the present model has strong empirical predictions(which are discussed in Section6).Another related paper is Kogan(2000)which studies the stock price of afirm engaged in irreversible real investment.The similarity obtains because the process of irreversible real investment is similar to the process of durable good investment which is studied in this paper.3The EquilibriumIn this section we will analyze the solution to the representative agent’s control problem,as well as the asset prices which obtain in equilibrium.3.1An Agent’s Control ProblemThe solution of a single agent’s problem will give us the solution to the equilibrium of the economy as long as(1)all agents have identical preferences,and(2)all agents start at time0 with identical ratios of nondurable to durable.We will assume that both of these conditions hold.The nondurable consumption in the current problem occurs at a rate c t.Investment into the durable good,however,may have a singular component.The latter problem has been studied in the literature as well.See papers by Hindy and Huang(1993),Dumas(1991), Shreve and Soner(1994)and the book by Harrison(1990),among others.The joint control of c t and the durable investment processΦt can be handled in much the same way as the control ofΦt alone.It turns out sufficient conditions for this problem are similar to the Bellman conditions of dynamic programming.This section will heuristically discuss the optimality conditions for the value function and control.The section concludes with the statement of a verification theorem.A more rigorous discussion,as well as the proof of the verification theorem,are provided in the Appendix.Let J(K t,z t,t)be the value function of a single agent.The solution of the control problem。