Chandra and Spitzer observations of CDFS X-ray obscured QSOs
高考英语 考前突破阅读理解能力 社会生活 墨西哥夫妇巨石下安家居住30年素材
墨西哥夫妇巨石下安家居住30年Mexican couple, a hut wedged below a 130-foot boulder in Coahulla, Mexico has been hom e for the past 30 years.对许多人而言，在岩石底下居住这一想法听起来像是笑话。
不过，对于一对墨西哥夫妇来讲，过去三十年，嵌在墨西哥Coahulla州的一块高达130英尺的巨石下的一个棚屋便是他们的家。
A hut wedged below a 130-foot boulder in Coahulla, Mexico has been home for thepast 30 years.A reporter recently visited the couple, Benito Hernandez and Santa Martha de la Cruz Villarreal, in their primitive desert home 50 miles south of Texas. Hernandez is a farmer who plants and collects the Ca ndelilla（蜡大戟） plant used in making Candelilla wax.He first saw this boulder（乱石，大圆石） 55 years ago, when he was eight, and decided to make it a home one day. Twenty years later he was able to secure rights to the land."I started coming here when I was eight-years-old to visit the Candelilla (harvesting) fields and I liked it here. I liked it and then I continued visiting every three to four months. I wasn't married and I didn't have a family yet b ut I liked it and I had to keep coming to put my foot in (on the property) beca use lands here are won through claiming them," Hernandez told the International Business Times.The home, made of sun-dried bricks and cement, has a dirt floor, a wood stove, and no plumbing（水管设施）. Elect rical service is said to be unreliable. A nearby stream supp lies fresh drinking water. In winter, though, the water source freezes over."It gets very cold here and we struggle to get food. We have to work hard here o n the C andelilla (fields). That's the only job we have. That's what we live from," said Hernandez.The couple have seven ch ildren, six of whom are married and live nearby.。
jagadish chandra bose阅读理解
jagadish chandra bose阅读理解If you were to see the Great Banyan Tree in the Acharya Jagadish Chandra Bose Indian Botanic Garden from a distance. you could be forgiven for mistaking it for a forest. Covering more than 14.493 square meters, the tree is the widest in the world. It is so large that it covers more ground than the average Wal-Mart.No one is quite sure exactly how old the Great Banyan Tree is due to the 1ack of official records, but experts guess that the tree is at least 250 years old. The earliest references to the tree have been found in travel writing dating from the 19th century. Over the years, the tree has gone through a lot. Not only has it survived two major disasters in 1864 and 1867; but its main trunk also caught a deadly disease. And because of the disease, the main trunk of the tree needed to be removed in 1925.Despite going through such a major surgery, the Great Banyan Tree proved resilient (能复原的).This is because of thousands of aerial roots(气生根) that grow from the tee's branches and go into the ground. And that is what gives the impression of a full forest ratherthan a single tree.Taking care of this 1arge tree is so difficult that it takes a 13-member team. Not only do they make sure the tree stays healthy. but they also“train" the roots to grow correctly.In Indian culture. banyan trees are among the most venerated. It is considered to be a sacred tree in various religions. For example, in Hinduism, it symbolizes longevity and represents the great God, Brahma. In Buddhism, banyan trees are also significant because it is believed that Buddha sat beneath one for 7 days.Want to see the Great Banyan Tree for yourself? The botanical garden is easily accessible by car or bus from the Kokata city center. As well as the Great Banyan Tree, you can also see a wide variety of plants from all around the world, making it an amazing journey.1、According to the article. the Great Banyan Tree_A. is the tllest tree in the worldB. is the widest tree in the worldC. is the strangest tree in the worldD. has the most branches in the world2、 What can we learn from Paragraph 2?A. The tree is exactly 250 years old.B. The tree has survived many disasters.C. The government has detailed records of the tree.D. The tree was planted in another place in the 1920s.3、Which of the following best explains“venerated" in Paragraph 5?A. respected.B. recorded.C. reminded.D. relieved.4、 What is the passage mainly about?A. India's Great Banyan Tree.B. Places you can visit in India.C. A botanic garden in India.D. The protection of the Great Banyan Tree.。
克劳德·麦凯《回到哈莱姆》中的跨国书写
克劳德•麦凯《回到哈莱姆》中的跨国书写舒进艳内容摘要：克劳德•麦凯的《回到哈莱姆》描摹了20世纪早期的黑人跨国体验。
学界主要阐释了作者个人的跨国经历与黑人国际主义思想对小说塑造主要人物的影响，而忽视了小说中副线主人公雷的国籍及其旅居哈莱姆的意义。
雷的跨国移民经历既再现了麦凯的复杂跨国情感与认同经历，又观照了哈莱姆作为流散非裔移居的理想家园与城市黑人社区所承载的空间意涵。
论文提出哈莱姆具有三个维度，作为移民唤起历史记忆的地理空间、建构跨国身份的政治空间及容纳差异的多元文化空间，并考察移民在跨国流动中历经的现代性体验，以此揭示他们通过改变既定身份与重新定义自我而竭力摆脱传统的民族、种族和阶级观念的束缚与身份认同的困惑，从而参与到美国城市的种族空间生产中。
关键词：克劳德•麦凯；《回到哈莱姆》；跨国书写基金项目：本文系国家社会科学重大项目“美国文学地理的文史考证与学科建构”（项目编号：16ZDA197）；天津市研究生科研创新项目“美国新现实主义小说的跨国空间研究”（项目编号：19YJSB039）的阶段性研究成果。
作者简介：舒进艳，南开大学外国语学院博士研究生、喀什大学外国语学院副教授，主要从事美国文学研究。
Title: Claude Mckay’s Transnational Writing in Home to HarlemAbstract: Claude McKay’s Home to Harlem depicts the black transnational experience of the early 20th century. Academics mainly studied the influence of McKay’s personal transnational experience and black internationalist thinking on his main character, but neglected the minor plot’s protagonist Ray and his nationality, and the significance of his sojourn in Harlem. Ray’s transnational migration experience not only embodies McKay’s complex transnational feeling and identity experience, but also reflects Harlem’s spatial significance as an ideal home for African diaspora and urban black community. The paper aims to examine Caribbean immigrants’ experience of modernity in Harlem which is interpreted as the geographic space for immigrants to evoke historical memories, the political space for constructing transnational identities and the multicultural space for accommodating differences. It is to prove that they manage to extricate themselves from the shackles of traditional concepts of nation, race and class and their confusion of identity by changing their established identity and redefining themselves, and thus participate in the production of racial space in American cities.60Foreign Language and Literature Research 2 (2021)外国语文研究2021年第2期Key words: Claude Mckay; Home to Harlem; transnational writingAuthor: Shu Jinyan is Ph. D. candidate at College of Foreign Languages, Nankai University (Tianjin, 300071, China), associate professor at School of Foreign Studies, Kashi University (Kashi 844000, China). Her major academic research interest includes American literature. E-mail: ******************1925年，阿伦•洛克在《新黑人》选集中将哈莱姆描述为一个国际化的文化之都，视其重要性堪比欧洲新兴民族国家的首都。
Macroscopic mechanical systems are entering the quantum world
PERSPECTIVES National Science Review2:9–15,2015PHYSICSMacroscopic mechanical systems are entering the quantum world Yong-Chun Liu and Yun-Feng Xiao∗In the classic Chinese novel Journey to the West,the Monkey King has a special power that enables him to be in two or more places simultaneously.Normally, an amazing thing such as this could never happen in real life.However,in the quantum world,where the motions of objects obey the rules of quantum me-chanics,this could happen.These weird quantum rules usually only apply in the microscopic world to atoms and molecules,because quantum properties are generally very fragile in the macro-scopic world.However,scientists have recently been making efforts to push macroscopic and mesoscopic mechanical systems into the quantum world,i.e.they are putting conventional mechanical systems into the quantum mechanical regime.Spring oscillators,swings,and pendu-lum clocks are typical mechanical sys-tems that we often see in daily lives, and they can be described by a basic physical model:the harmonic oscilla-tor.In the quantum regime,harmonic oscillators have some quantum proper-ties,including discrete energy spectra and zero-point motion.To observe these quantum properties,the environmental thermal noise must be suppressed so that the energy of the quantum motion domi-nates over the energy of the thermal mo-tion.To this end,a generic model of a cavity optomechanical system is used, as shown in Fig.1.The system consists of an optical cavity with a fixed mirror and a movable mirror,where the lat-ter is attached to a spring and under-goes harmonic oscillation.A laser beam is launched into the cavity and is reflected multiple times between the two mirrors,and the cavity field thus builds up,re-sulting in a greatly enhanced optical field,which then exerts a considerable force onthe movable mirror.The interaction be-tween the optical field and the mechan-ical motion can reduce the thermal mo-tion noise to enable the fragile quantumproperties to be observed.The study of such systems has pro-duced an emerging field called cavityoptomechanics[1–3].The pioneeringwork was conducted by Braginsky andco-workers in the1960s[4].In recentyears,various experimental systemshave been proposed and investigated,including Fabry–P´e rot cavities[bygroups including MIT/Caltech LIGOLaboratory,the Mavalvala group at MIT,the Aspelmeyer group at the Universityof Vienna,the Heidmann group at theUniversity of Pierre and Marie Curie,and the Bouwmeester group at theUniversity of California,Santa Barbara(UCSB)],whispering-gallery cavities(by groups including the Vahala group atCaltech,the Kippenberg group at´EcolePolytechnique F´e d´e rale de Lausanne,the Wang group at the University ofOregon,the Lipson group at CornellUniversity,the Carmon group at theUniversity of Michigan,the BowenL a s e r in p u tFixed mirror Movable mirrorFigure1.Illustration of a generic cavity op-tomechanical system.The left mirror is fixedand the right mirror is attached to a spring.group at the University of Queensland,and the Xiao group at Peking Univer-sity),photonic crystal cavities(by groupsincluding the Painter group at Caltech,the Wong group at Columbia Univer-sity,and the Tang group at Yale Uni-versity),separated mechanical oscillatorsinside or near a cavity(by groups in-cluding the Harris group at Yale Univer-sity,the Regal group at Joint Institutefor Laboratory Astrophysics(JILA),theFavero group at Paris Diderot Univer-sity,and the Weig group at the Univer-sity of Munich),superconducting circuits(by groups including the Schwab groupat Caltech,the Lehnert group at JILA,theCleland group at UCSB,and the Teufelgroup at National Institute of Science andTechnology,Boulder),and cold atoms(by groups including the Kimble group atCaltech,the Stamper-Kurn group at theUniversity of California,Berkeley,andthe Treutlein group at the University ofBasel).Cavity optomechanics has beenfeatured as the most recent milestone inphoton history in Nature.The researchin cavity optomechanics is importantto both fundamental physics studiesand the applied sciences.First,cav-ity optomechanics provides a uniqueplatform for the study of fundamentalquantum physics,including macroscopicquantum phenomena,decoherence,and quantum–classical transitions.Thefield offers the best test bed to studyeffects like gravity-induced decoherence,which is important to the understandingof macroscopic quantum phenomena.Second,cavity optomechanics is promis-ing for high-precision measurements ofsmall forces,masses,displacements,andC The Author(s)2014.Published by Oxford University Press on behalf of China Science Publishing&Media Ltd.All rights reserved.For Permissions,please email:journals. permissions@10Natl Sci Rev ,2015,Vol.2,No.1PERSPECTIVESYear (a)(b)N u m b e r o f p u b l i c a t i o n sN u m b e r o f c i t a t i o n s200200200200200201201201201Year200200200200200201201201201Figure 2.Numbers of publications (a)and citations (b)per year in the period from 2005to 2013with the keyword ‘cavity optomechanics’,retrieved from the Web of Science.accelerations,and is considered to be capable of surpassing the standard quan-tum limit.Third,cavity optomechanics provides resources for both classical and quantum information processing.For instance,optomechanical devices can serve as information storage devices and act as interfaces between light beams with different wavelengths or even microwaves.In the last few years,researchers have made considerable efforts to put mechanical systems into their quan-tum ground states [5].Recent efforts have demonstrated optomechanically induced transparency [6],normal-mode splitting [7],quantum-coherent coupling [8],wavelength conversion [9],and measurements performed below the standard quantum limit [10].Future de-velopments will aim to integrate different quantum systems to form hybrid quan-tum devices,e.g.hybrid optomechanical and electromechanical systems.In this way,we can enable phonons,photons,and electrons to work together in the quantum world.Recent years have seen rapidly grow-ing interest in the field of cavity optome-chanics.As shown in Fig.2,the publica-tions and citations in this field have grown exponentially.The now booming devel-opment in this field will turn the dream of manipulating macroscopic mechani-cal systems in a quantum manner into reality.Yong-Chun Liu and Yun-Feng Xiao ∗School of Physics,Peking University,China;Collaborative Innovation Center of Quantum Matter,China∗Corresponding author.E-mail:ycliu@REFERENCES1.Kippenberg,TJ and Vahala,KJ.Science 2008;321:1172–6.2.Aspelmeyer,M,Kippenberg,TJ and Marquardt,F.2013;arXiv:1303.0733.3.Liu,YC,Hu,YW and Wong,CW et al.Chin Phys B 2013;22:114213.4.Braginsky,VB and Manukin,AB.Sov Phys-JETP 1967;25:653–5.5.Chan,J,Alegre,TPM and Safavi-Naeini,AH et al.Nature 2011;478:89–92.6.Weis,S,Rivi`e re,R and Del´e glise,S et al.Science 2010;330:1520–3.7.Gr¨o blacher,S,Hammerer,K and Vanner,MR et al.Nature 2009;460:724–7.8.Verhagen,E,Del´e glise,S and Weis,S et al.Nature 2012;482:63–7.9.Dong,C,Fiore,V and Kuzyk,MC et al.Science 2012;338:1609–13.10.Gavartin,E,Verlot,P and Kippenberg,TJ.Nat Nanotechnol 2012;7:509–14.doi:10.1093/nsr/nwu050Advance access publication 21August 2014IMMUNOLOGYTargeting the immune system:a new horizon of cancer therapiesChen DongINTRODUCTIONThe immune system is our trustworthy army of defense against invasion of mi-croorganisms.As the first line in this army,the innate immune system,com-posed of myeloid cells (dendritic cells and macrophages),some lymphocytes (NK cells and innate lymphocytes as well as some types of T lymphocytes such as NKT cells and γδT cells)and other cells in our body,can quickly mountinflammatory responses after the spe-cific receptors in these cells recognize the pathogen-associated pattern molecules inside or outside host cells.The adap-tive immune system,consisting of B and T lymphocytes,is slower in their acti-vation,but it is more specific in their antigenic recognition and long-lasting,owing to the generation of memory lym-phocytes.Two major types of T lym-phocytes that carry αβT cell receptorshave different functions—those express the CD4molecule secrete cytokines to regulate immune function and are called helper T cells,while those express CD8co-receptor are called cytotoxic T lym-phocytes (CTL)and can directly kill cells infected by viruses.The immune system has an intimate relationship with cancer.Immune cells,such as myeloid cells and lymphocytes,are frequently found in the tumor。
北极冻土层英文阅读理解
北极冻土层英文阅读理解The Arctic tundra, a vast expanse of frozen soil, holds secrets that have been frozen in time for centuries. With layers of permafrost extending deep beneath the surface,it's a natural freezer for ancient remains and organisms.Exploring the tundra feels like stepping into a world untouched by modern civilization. The cold air bites at your nose, and the quiet is so absolute, you can almost hear the earth breathe. Beneath the snow and ice, there's a story that's slowly being revealed to us.The frozen soil acts as a time capsule, preserving things that have been lost to the rest of the world. From ancient mammals to mysterious microbes, the tundra is a treasure trove for scientists. But as the climate warms, these fragile ecosystems are under threat.Walking across the tundra, you can see evidence of how the environment is changing. Pools of meltwater form whereonce there was solid ice. Plants are beginning to grow in areas that were once barren. It's a reminder of thefragility of our planet and the need to protect these unique habitats.And yet, there's beauty in this desolate landscape. The stark contrast between the white snow and the blue sky is breathtaking. The silence is deafening, yet it's a silence that feels cleansing and pure. In the Arctic tundra, nature is at its most raw and unforgiving, yet it's also its most captivating.。
blooming daisies英文原版
blooming daisies英文原版Blooming Daisies is a heartwarming novel set in a small town in rural America. The story revolves around Sarah, a young woman who inherits her grandmother's flower shop after her passing. With great determination and a love for flowers, Sarah embarks on a journey to revitalize the shop and make it a thriving business once again. Along the way, she discovers the power of community, love, and the importance of following one's passion.The novel opens with Sarah's return to her hometown after several years of living in the city. She feels a deep connection to the flower shop that her grandmother had nurtured for decades, and is determined to honor her memory by restoring it to its former glory. As Sarah immerses herself in the work, she faces numerous challenges, from financial difficulties to competition from larger floral chains.Sarah's genuine love for flowers and her dedication to her craft is evident throughout the novel. She spends hours carefully arranging bouquets and creating stunning floral designs. With each arrangement, she manages to capture the essence of the blooming daisies, bringing joy and beauty to her customers' lives. It is through her passion and artistic talent that she begins to attract customers back to her shop, gradually building a loyal clientele. The importance of community is a recurring theme in the narrative. Sarah finds support and guidance from her neighbors, friends, and even some unexpected sources. The tight-knit community rallies around her, helping to spread the word about her shop and promoting her business through word-of-mouth. As the towncomes together to support Sarah's endeavor, it becomes clear that the success of the flower shop is not just about Sarah's dream but a symbol of hope and revitalization for the entire community.Love also plays a central role in the story. Sarah reconnects with her high school sweetheart, Jack, who had stayed behind in the town while she pursued her dreams in the city. Their rekindled romance adds an element of nostalgia and sweetness to the narrative. Jack becomes a pillar of support for Sarah, not only as a love interest but also as a partner in her business venture. Together, they overcome obstacles and celebrate triumphs, solidifying their bond and proving that love can be an essential driving force in achieving dreams.Throughout the novel, the author beautifully captures the spirit of the blooming daisies that Sarah so adores. The delicate petals and vibrant colors of the flowers symbolize resilience and growth, reflecting the journey of both Sarah and the town. The vivid descriptions of the floral arrangements and the scents that fill the air transport the readers into Sarah's world, immersing them in the beauty of nature.In conclusion, Blooming Daisies is a heartwarming novel that celebrates the power of following one's passion, the importance of community, and the beauty of love. Through Sarah's journey to revive her grandmother's flower shop, readers are reminded of the joy that can be found in pursuing one's dreams and the transformative power of nature. The novel serves as a testament to the resilience of small towns and the invaluable support of a close-knit community.。
英美概况课后习题答案
1. What is the full name of the .?----United Kingdom of Great Britain and Northern Ireland2. Why do tourists from all over the world like to go to Scotland?----They like to enjoy the beautiful Scottish scenery, to drink Scotch whisky and to see Scotsmen wearing kilts and playing bagpipes.3. How many periods can the development of the English language be divided into and what are they?----The development of the English language can be divided into three periods: Old English, Middle English and Modern English.4. Why did English become more important after Black Death?----The laboring and merchant classes grew in economic and social importance after the Black Death, so English also grew in importance compared to French.1. Who are the British People?----The first known inhabitants in Britain were Celts who are the ancestors of the Welsh, Scottish and Irish people. Then came the Anglos, the Saxons and the Jutes who brought with them the English language. Many people from other European countries came later, and in modern times there are a lot of immigrants from many former Commonwealth countries from every part of the world. Britain is a country of mixed cultures, and the Britain people are also composed of people from different ethic and culture backgrounds.2. What is Standard English?----Standard English is based on the speech of the upper class of southeastern England. It is widely used in media and taught at schools. It is preferred by the educated, middle-class people. It has developed and has been promoted as a model for correct Britain English. It is also the norm carried overseas. Today, Standard English is codified to the extent that the grammar and vocabulary are much the same everywhere in the world where English is taught and used.1. What are the two components of the British Parliament?----the House of Commons and the House of Lords.2. What were some of Queen Victoria's major achievement?---- Queen Victoria made tremendous achievements in almost every aspect.She promoted further industrial revolution, the building of railways and the growing of trade and commerce. By the end of her reign, Britain had developed to an empire including a quarter of the global population and nearly a quarter of the world's landmass.3. What were the two camps in Europe in World War 1?----The Central Powers which included Germany, Austria-Hungary, the Ottoman Empire and Bulgaria and the Allied Powers which were mainly comprised of France, the Russia Empire, the Britain Empire, Italy and the United States.4. Why did Britain cooperate closely with the United States after World War 2?----Because they were allied during the war and shared the same worries about the former Soviet Union.1. What were the results of the Industrial Revolution in Britain?----The Industrial Revolution changed Britain in many ways. First, industrial country increased dramatically. Britain became the most advanced industrial country and also the financial center in the world. Second, urbanization took place. Many new cities sprang up. Third, it caused great changes in the class structure. The old social classes declined, and new ones emerged and developed.2. The Rise and Fall of the British Empire?----Colonization of Newfoundland, the first British colony overseas, in 1583 marked the beginning of the British Empire. By 1837, British had long been an empire which included the colonies in Canada, Australia, New Zealand, India and many small states in the West Indies. By the end of 19th century, the British Empire included a quarter of the global population and nearly a quarter of the world's landmass. During the mid-19th century, the British government consolidated the existing colonies by bringing them under the direct control of the government. Before World War 1, Britain had the largest colonial empire in the world. However, Britain suffered great loss to its manpower in the two World Wars and exhausted its reserves of gold, dollars and overseas investment. Most of Britain's colonies gained independence since the 1940s, which inevitably led to the fall the Empire.1. What are the three functions of the House of Commons?----to draft laws, to scrutinize, criticize and restrain the activities of the government, and to influence future government policy.2. Why is the Conservative Party sometimes called the "Right"?----Because the Conservative Party is supported by landowners and businessmen, who are often from the middle and upper-middle class.3. What kind of public image does Liberal Democrats have in Britain?----The Liberal Democrats is perceived as "middle" between the Conservative and the Labor Party. It is comparatively flexible and pragmatic in its balance of the individual and the social. It emphasizes the need for a change in Britain's constitutional arrangements to make the government more democratic and accountable.4. Why are independent candidates unlikely to win in the general election? ----Because even if they were elected, they would be powerless in Parliament. Therefore, it is not possible for many people to vote for independent candidates.1. What do British electoral campaigns usually involve during the process of a general election?----The electoral campaigns usually involve advertising in newspapers, door-to-door campaigning and leaflets. The main parties are given short periods of time on national television to present their policies to the public. Apart from the parties' own publicity, newspapers and TV programs spend a lot of time discussing the campaign, interviewing politicians, and predicting the results.2. What is the Commonwealth of Nations?----The Commonwealth of Nations is a voluntary association of independent sovereign states, all of which acknowledge the British monarch as the head. The Commonwealth is not a political union of any sort, and its member states have full autonomy to manage their internal and external affairs. It is primarily an organization in which countries with diverse economic backgrounds have an opportunity for close and equal interaction after gaining independence. The major activities of the Commonwealth are designed to advocate democracy, human rights, and to promote economic cooperation and growth within its members.1. What was the negative aspect of Thatcher's reform in the early 1980s? ----Its negative aspect was a rapid increase in unemployment. In 1982, the unemployment rate reached the level of the Great Depression years, with three million people out of work.2. What are the characteristics of Britain's agriculture?----British's agriculture is characterized by a small portion of the population engaged in agricultural activities with a high degree of mechanization. Although it employs a mere 1% of the country's labor force, it meets around 60% of the national demands.3. What happened to Britain's beef industry in the mid-1990s?----British's beef industry was hit badly by BSE, resulting in a ban on beef exports in 1996.4. What are some of the popular tourist attraction in Britain?----The popular tourist attractions in English include: the Dorset and the East Devon Coast, the Lake District, Stonehenge, Windsor Castle, university towns of Oxford and Cambridge, Tower of London, St. Paul's Cathedral and so on.1. What were the major causes of Britain's relative economic decline in the postwar period?----British's economy experienced a relative decline in the postwar period for several reasons. First, British suffered a great losses in the two World Wars and had gone heavily into debt to finance the war. Second, the era of the British Empire was over. India and other British colonies, which provided raw material and large market for British goods, gained their independence. Third, British was forced to maintain an expensive military presence in many overseas locations until the end of 1960s. Fourth, British had to make substantial financial contributions to NATO and UN Security Council. Finally, British failed to invest in industry after World War 2 whereas its competitors like Germany and Japan caught up with British buy investing in the most modern equipment and means of production.2. Why do developed nations like Britain encourage the development of the service industry?----The service industry has played an increasingly important role in economy in the development countries. On the other hand ,it requires a large group of people working in it so that abundant employmentopportunities are provided. On the other hand, the service industry causes little pollution.1. What used to be the major functions of grammar schools and vocational schools in Britain?----The major functions of grammar schools were to train the most academically capable students and prepare them for university, whereas the major functions of vocational schools were to help less successful students to learn a trade.2. What kind of subjects do Britain comprehensive schools provide?----British comprehensive schools provide a general education, offering both academic subjects like literature and science, and practical subjects like cooking and carpentry.3. In what ways do Britain universities enjoy complete academic freedom? ----British universities enjoy complete academic freedom because they can appoint their own staff, decide which students to admit, provide their own courses and award their own degrees.4. How do students in the Open University receive their education?----The students follow university courses through textbooks, TV and radio broadcasts, correspondence, video, and a network of study centers.5. What role does the media play in Britain leisure culture?----The media plays an essential role in British leisure culture since it helps to shape the public's opinion, determine people's moral and political orientation and consolidate or undermine the rule of a government.1. What are the general feature of Britain's independent schools?----British's independent schools require fees from students. Although the National Curriculum is optional in the independent system, most independent schools teach what the curriculum demands. Independent schools get their funding through tuition fees as well as government assistance. Since they are generally better-funded than most state schools, they can recruit the best teachers and provide superior facilities. However, high tuition fees have become an obstacle for many students to enroll.2. The "quality press" and the "tabloids" in Britain?----Among the 10 daily published national newspapers in British, about half of them are regarded as the "quality press" since they carry in-depth articles of particular political and social importance, and reviews and feature articles about "high culture", and they are generally read by well-educated people. The Times, The Guardian and The Daily Telegraph are good cases in point of the quality press. The "tabloids", with color photos and striking headlines, usually cover scandals and gossip about celebrities in politics, sports and entertainment. A typical example is The News of the World.Chapter 81. How is the American population distributed?The distribution of the American population is rather uneven the most densely populated region is the northeastern part of the country. The great plains have a comparatively small population .the south also has a population of almost . the west is not densely populated ,except for some metropolitan centers like los Angeles and san Francisco . it has about 20% of the nation’s population.2. Why was the immigration act of 1942 instituted ?The new immigrants in the united states , being poor and accustomed to poverty , were willing to work for very low wages .this made other workers afraid that the immigrants would ls and take jobs away from them . this opposition led to the immigration act of 1942.1．Why is the United States regarded as a”melting pot” and a ”salad bowl” ?The United States is not merely a nation, but a nation of nations. The immigrants came in waves, including the Europeans, the Africans and the Asians. Therefore, America is described as a "melting pot" where various racial and ethnic groups are assimilate into American culture. Recently, America has been called a "salad bowl" in that people of difference races and ethnic groups mix harmoniously, but at the same time keep their distinct culture and customs.2．What do you think is the best way to help assimilation in a multicultural society?The best possible way to help assimilation in a multicultural society is to be open and tolerant toward different cultures. People from different racial and ethnic backgrounds should respect each other. Society should create opportunities to help immigrants become assimilated. At the same time the immigrants should keep their own language, customs and religion, contributing to the diversity of a multicultural society.Chapter 91. Why did American change its policy and enter world war II?Because of the formation of the axis , the American government feared that the axis countries were wining the war and it might threaten America’s security and interests . it began to provide war equipment to the foreign nations resisting the aggression of the axis power . the Japanese air raid on pearl harbor became the direct cause for America’s entrance into the war.2. What were Nixon’s well-known contributions during his presidency?a) brought the Vietnam war to a closeb)reestablishing . relations with chinac) negotiating the firststrategic arms limitation treaty with the former soviet union .3. What were the contents of Reagan’s economic program?Reagan’s economic program called for reductions in income taxes and business taxes in order to encourage investment , and it also requested that many government regulations be eliminated so as to reduce the federal government’s role in the day-to-day operation of business.1. What was the cause of the American Civil War?The Southern planters of America needed a large number of black African slaves to manage their plantations and they regarded the slaves as their property. In the North, with the development of industry, there was a growing demand for free labor. What’s more, the Northerners demanded a law to protect tariffs and asked the government to finance the building of railways and roads. But the Southerners were against it and advocatedfree trade so as to purchase cheaper goods from foreign countries. The accumulating conflicts led to the division of the North and the South and finally the American Civil War.2. What made the United States a powerful country by the end of World War II?During the two World Wars, America remained neutral in the early stage. However, Americans continued their profitable trade with the warring countries. Therefore, they not only retained their military forces, but also accumulated great wealth. When America entered the wars, it was almost at the end of the wars. By sharing the fruit of victory with other allies, America greatly strengthened its power and became a powerful country by the end of World War II.Chapter 101. What are the two characteristics of the . constitution?One is “checks and balances”, the other is that the power of the central government and the powers of state governments are specified.2. What are the qualifications for a senator and a representative respectively?A senator must be over 30 years old , a . citizen for at least nine years, and a resident in the state which they represent . a representative should be at least 25 years old and a . citizen for no less than seven years.3. What are the major powers of the supreme court?a) to interpret lawsb) to hear appeals from any federal court cases;c) to hear appeals from state court cases that involve the constitution or national laws d) may declare a law unconstitutionale) may declare a presidential act unconstitutional4. What is the difference between the democrats and the republicans in terms of political opinions?The democrats want the government to play an important role in the economy and emphasize full employment as a matter of national concern they favor civil rights laws , a strong social security system which gives enterprises a greater freedom and demand that the government control inflation. They stress the need for law and order, and oppose complete government social programs and free choice of abortion they also favor a strong military posture and assertive stand in international relations.1. How is the American President voted into office? What are your ideas about the American election?Each party holds its national convention every four years to choose a candidate for presidency. To win a presidential election, a candidate has to spend millions of dollars, travel all over the country to make speeches and debate on television with the rival. The general election is technically divided into two stages. During the first stage, presidential electors for each state will be chosen. In the second stage the electors meet and vote a President. Since the second stage is only a kind of formality, everyone knows who will be the next President an soon as the first stage is over.I think the candidates spend too much money on the electoral campaigns. And, the election cannot solve the social and economic problems of the . as some candidates do not keep their word after they become President.2. What was President Eisenhowers foreign policy and what were the consequences ?President Eisenhower made vigorous efforts to wage the Cold War. He placed new emphasis on developing nuclear strength to prevent the outbreak of war. He also frequently authorized the CIA to undertake secret interventions to overthrow unfriendly governments or protect reliable anti-communist leaders whose power was threatened. The CIA helped topple the governments of Iran and Guatemala, but it suffered an embarrassing failure in Indonesia. In addition, Eisenhower used . power and prestige to help create a non-communist government in South Vietnam, which brought disastrous long-term consequences to the United States.Chapter 111. What industry developments took place during the colonial period of America?During the colonial period ,the secondary industries developed as the colonies grew . a variety of specialized sawmills and gristmills appeared. Colonists established shipyards to build fishing fleets and trading vessels . they also built small iron forges . by the 18th century , regional patterns of development in America had become clear.2. How did the civil war affect the American economy?After the civil war , the large southern cotton plantations became much less profitable . northern industries , which had expanded rapidly because of the demands of the war ,surged ahead.3. Why does America try to reduce trade barriers?Because the united states has increasingly realized that open bilateral trade will not only advance its own economic interests, but also enhance domestic stability and its peaceful relationship with other nations.1. How did the constitution lay the groundwork for American’s economic development ?The . Constitution, as an economic charter, established that the entire nation was a unified or "common" market. There were no tariffs or taxes on interstate commerce. It provided that the federal government could regulate commerce with foreign nations and among the states, establish uniform bankruptcy laws, create money and regulate its value, fix standards of weights and measures, establish post office and roads, and fix rules governing patents and copyrights. The last-mentioned clause was an early recognition of the importance of "intellectual property", a matter that began assuming great importance in trade negotiations since the late 20thcentury.2. Cite examples to illustrate the role of government intervention in America's economic development.The government has always played an active and important role in America’s economic development. In the early 1930s,thr United States suffered the worst economic depression in American history. President Roosevelt introduced the New Deal to tackle the financial crisis. Besides, he set up the New York State Emergency Relief Commission to help those in desperate need and tried to relieve the serious problems of the jobless. At the end of 1970s, the American economy again suffered a recession. TheReagan administration combated inflation by controlling government spending deficit, cutting taxes and raising interest rates. Both policies mentioned above helped to set the country’s economic development on its right course, In all, the intervention of the government has ensured that economic opportunities are fair and accessible to the people. It has prevented flagrant abuses of the system, dampened the effects of inflation and stimulated economic growth.Chapter 121. How does an American university choose its applicants?a)their high school records;b) recommendations from their high school teachers;c) the impression they make during interviews at the university;d) their scores on the SAT.2. What functions do American higher education institutions perform?Higher education institutions in the united states have three functions: teaching , research and public service , and each has its own emphasis with regard to its function .3. What similarities do four famous university share?They all have a long history , they all have an excellent faculty , a large number of students and have made extensive academic achievements. Some of their graduates are very successful or influential in some areas such as politics, arts and business.4. What are the origins of thanksgiving day?Thanksgiving is associated with the time when Europeans first came to the new world , in 1620,the mayflower arrived and brought about 150 pilgrims. Life at the beginning was very hard and there was not enough food , so many of them died. During the following summer the native America helped them and then they had a bountiful harvest. So they held a big celebration to thank god and the native Americans.1. What are the ideals that guide the American educational system?The first ideal is that as many people as possible should receive as much education as possible .The second ideal is that of ptoducing a society that is totally literate and of local control . The third ideal is that scholars and students should work to discover new information or conceive new ways to understand what is already known .2. How does America carry out multicultural education?American schools routinely teach the experiences and values of many ethnic cultures. Current textbooks incorporate a variety of ethnic individuals who have achieved success. Struggle for equality are vividly depicted, and past racism is bluntly acknowledged. Cultural pluralism is now generally recognized as the organizing principle of at all levels offer students opportunities to learn about different cultures.。
女性空间和诗意空间_克里斯蒂娃对拉康的批判_英文_
[作者简介]周雪滢,女,河北新河人,北京外国语大学外国文学研究所硕士研究生,研究方向:英美文学与文论。
R ecreating theM a terna l and the Poetic Space:K r isteva .s C r itique of LacanoZhou Xueyi ng(F oreign Litera ture Rese arc h Instit u te ,Beiji n g Forei g n St u d ies Un iversit y ,Beijing,100089)[A bstra ct] A lt hough im m ense ly i ndeb ted to Lacan .s theory t hat enjoys tre m endous po pular i ty in t wentieth century literary criticis m,Kr i steva sets out to cha llenge Lacan f unda m ental presuppos iti ons and demonstra tes Lacan .s m i sread i ng of F reud desp ite of h i s o wn m anifesto of /R et u rn to F reud 0.Th is paper de m o nstrates ho w K risteva re-creates t he m aterna l and the poe ti c space that has lo ng been den i ed ph ilosophica ll y by t heor izi ng concepts of abjecti on ,sem iotic and he terogene 2ity ,as opposed to Lacan .s co ncept of sy m boli c orde r ,S /s algorith m,and ho m ol ogous structure .[K ey words] Kr i steva ; Lacan; cr iti que ; t he se m i otic ; m aterna l space ; poetic space [中图分类号]I106.4 [文献标识码]A [文章编号]167228610(2010)0720038203I .Intr oductionW h ile Lacan s weeps the wor l d w ith his theory on t he o m ni p 2otent sy m boli c order tha t co nfounds real hu m an agency and crushes the m aterna l and t he poe ti c with the do m i nant force of the pa ternal law ,fe m i n i sts fee l co n fined and repressed i n the pha llocentric worl d posed by Lacan .In PL MA ,Shu li Barzila i publis hed her land m ark essay en titled /Borders of Lang uage ,K risteva .s Cr iti que of Lacan 0where s he d i scusses Kr i steva .s challenge to Lacan .s sy m boli c order wh ich is do m ina ted by the paterna l l aw ,and ill ustrates Kr i steva .s key ter m s such as /ab 2jecti on 0,/the se m i otic 0.W hil e mak i ng a brief su mma ry of so m e of Barzila i .s co mm ents on K risteva ,the paper expl ores the intr i cate li neage among F reud ,Lacan and K risteva i n t he ir re 2spective theore tica l propositi ons .Ò.K r isteva .s C r it i que of La ca n2.1K risteva .s key co ncept )ab jecti on as opposed to sy m 2bolic orderTo pro ve the li m i tati ons of the sy m boli c orde r ,Kristeva ra ises t he examp l e of border li ne patien ts whose discourses are alo gica,l chaoti c and i nco mprehensi ble .The o mn i potent lan 2guage see m s l ose its effec t ,wh ile so m eth i ng irreduc i b l e t o lan 2guage em erges ,resu lted fro m the o utbreak of ab j ectio n .W hat is ab j ect dra ws us /to wards t he place where meaning collap 2ses 0.[1]2Kr i steva .s theory of ab j ec ti on striki ngl y opposes the Lacanian t heory of t he do m i nant paterna l l aw of t he sy mbolic order tha t i nscr i bes every i ndivi dua.l F or a be tter unde rstand i ng of Kristeva .s t heoretica l revolt aga i nst Lacan ,the essen tia l kno wledge of ab j ectio n is requ ired .W hat i s abjecti on ?In dicti onary ,/ab 0m eans /away 0,and/j ec t 0means /to t hro w 0,but ab j ectio n is a very co mp licatedter m i n Kr i steva .s theory .The origi nal for m of ab j ec tion is pos i 2ti oned i n the per i od be t w een the ch il d .s birth and the m irror stage .A fte r t he b i rth ,t he chil d i s i nti m ate l y connected w ith the m other .s bo dy .Under t he stro ng archa ic i m pu lse of establi sh i ng itself as a subject ,t he fut ure subject rejects t he m other .s body insti nctively i n order t o dra w a border be t w een self and t he(m )othe r ¹.H o weve r ,abjectio n i s neve r a peacef u l process ,/it is a vi olent ,cl um sy break i ng away ,w ith the constant r i sk of f a ll 2ing back under the s way of a po wer as secur i ng as it is sti 2fli ng 0[1]130,wh ich i s to say that t he border is fragile ,war m th of the m othe r constantl y ca lli ng the ch ild back to the pr i m itive chaos .A fter t he establish m ent of subjecti vity ,K risteva states t hat the abjectio n is not co m plete l y repressed and it is still ever ready to take effect .In th i s stage ,ab jecti on refe rs to peop l e .s horr ifi ed or d isg usted reacti on to t he threa ten i ng collapse i n m ean i ng/order caused by the bl urr i ng or l oss of d i sti nctio n /border .For instance ,Kristeva presents t he examp l e of people .s reac ti on of d i sgust and horror to wards the corpse .P eo p l e .s d i sgusted reac 2ti on to wards the corpse is e ffectively exercised i n t he bo dy ,which i m pli es tha t /visceral reac tion as a representati on of what is happen i ng i n the psyche .0[2]33On one hand ,human be i ngs have to m ake a d isti nctio n be t w een the /I 0(a li vi ng be i ng)and the /othe r 0(dea t h)i n order to stay i n the sy mbolic orde r .On the ot her ,peo p le can not deny t he fact of m an .s m orta lity and corporea lity .Through abjecti on ,t he border is established ,but on l y te m porar ily so because ab j ec ti on /does not respect bor 2ders 0[1]4and i s ever ready to d i srupt or dissolve the border .E lizabe t h Grosz descr i bes ab jec ti on i n the sy m boli c order as /ex 2cessi ve resi due left untapped by t he sy mbolic functi on 0[3]87,)38)语文学刊#外语教育教学 2010年第7期wh ich m eans t hat abjecti on is situated i n the bli nd areas of the sy m boli c,the pre-m ean i ng areas.Ab j ectio n d we lls in t wo for m s.In t he for m er,abjecti on is sit uated i n an absence of the border,whereas i n t he latter,ab j ectio n i s situated i n a b l urr i ng or collapse of the border.In both cases,abjecti on is a borde rli ne cond iti on,as K risteva puts it:/abjecti on i s above a lla mb i gu it y0.[1]9S i m p l y speaki ng,because of the o utbreak of abjecti on,the border li ne pati ents experience the collapse of the border bet ween /I0and t he worl d and l ose sub j ec tivity.In t he treat m ent of the border li ne pati ents,Kr i steva e m plo ys a stra tegy of/construc ti on &co ndensatio n0.Constructi on i s co mpared t o/t hema ti c read2 i ng0i n literature,referr i ng to the atte m pt to/repa ir the paterna l functi on0[4]301.Condensa ti on is only rough l y co m pared to deco n2 structi onº,re ferri ng to the m aterna l approach t hat reacti va tes the patients.pre-sy m boli c cond iti on.In co ndensatio n approach, the ana l yst i m itates borderli ne pati ents.the nonsens i ca,l alogi ca l p l ay ofwords i n order to activate the more bi ndi ng effect of the m aterna l transference.It.s wort h noting thatK risteva e m phasizes tha t both constructi on and condensa ti on are i m portant,we can not exc l ude any one of them,but dep l oy them together.K risteva.s ma terna l psychoana l yti c approach of condensa ti on is functi onall y the sa m e yet i n trins i ca lly different fro m Lacan.s pa2 terna l approach of d isplace m can.s disp l ace m ent m eans a third party,the paterna l la w,rep laci ng the chil d.s i nti m ate re l a2 ti onshi p w i th the m ot her.Through acqu iri ng lang uage,the ch ild is irretr i evably transfe rred to the next stage)the sy m bolic stage. Lacan.s approach of d i sp lacem ent doesn.t work for these borde2 rli ne pati ents f or who m the lang uage gives up.In co n trast to Lacan.s displace m ent,Kr i steva.s condensati on m eans the ch il d.s uni on with the mother.Thro ug h t he fusi on with the m other,the patient is able to be re-i m m ersed i n the pre-sy m2 bolic i nfantile stage whe re ab j ec tion is tak i ng effect f or t he patient to abject t he m other to ga i n sub j ectivit y.In her essay,Barzila i interprets m etaphor i ca ll y:by experienc i ng of/death-i n-the-m other0[4]302,the patient gains a chance of/a seco nd birth0 where t hey can reestabli sh their sub j ec ti vity,a precond i tio n f or the sy m boli c stage.The treat m ent of borde rli ne pa tien ts testifi es to the li m itati ons of Lacan.s phall ocentr i c approach of d i sp lace2 m ent.Kr i steva.s dialectic approach co mb i ned with both the paterna l of constructi on and t he m aterna l of condensa ti on proves h i ghly effecti ve.Th i s borde rline co nditio n,accordi ng toK risteva,i s not o n l y a pathologi ca l entity,but a pe rvasive aspec t i n hu m an life.K risteva c riticizes Lacan for havi ng made a ll e l em ents i nto a ho2 m ologo us struct u re»as the expense of ig nor i ng the hetero geneo us ele m ents.Th i s so-call ed hetero gene it y can a l so be traced i n po2 e ti c lang uage:sound,rhyth m,i m age and even the musc le move2 m ents wh i ch be l ong to non-verba l category,serves e l ementa l functi on i n poe ti c d isco urses.H o wever,Lacan.s S/s a l gor it h m ob literates such heterogene ity.2.2K risteva.s theory of the se m i oti cH eterogene ity i s c l osely re lated to Kr i steva.s t heory of the se m i oti c.Un li ke t he/classical se m i oti cs0,t he sem iotic i s not a sta ti c m ode of arti culatio n,but it is do m ina ted by t he pre-m ean i ng i nfantile drives t hat are fl u i d and mu lti-directi ona.l Therefore,if t he sub ject is to beco m e soc i a li zed i n the wor l d,those li b i d i nal dri ves need to be regu l a ted/as if it were chopped up0i nto/stable ter m s0.H o wever t he repressi on i s notco mp l e te,/for the se m i oti c can still be discerned as a k i nd of pulsi onal pressure w it h i n l anguage itsel,f i n tone,rhyth m,the bodily and m a terial qua li ties of l anguage,but a lso i n contrad i c2 ti on,m ean i ngless,disruptio n,silence and absence0.[5]163 K risteva m a i nta i ns that/si gnificati on0is co mposed of t wo essenti a l parts,the sy m bolic and t he se m i oti c.On the one hand, assoc i a ted w it h m ean i ng,the sy m boli c i s a Lacan i an model of the paterna l l aw,which i s struc t ura l and conventi ona.l On the ot her, assoc i a ted with pre-m ean i ng,t he se m i otic is K risteva.s theory of the m ate rna,l wh ich i s m ulti-directi ona l and unspeakable. Li nguisti ca lly speaking,wh ile the f or m er is about the struc t ure or gramm ar tha t governs t he l anguage system,the latte r is abo u t un2 regulated li b i d i na l dr i ves m an ifested i n rhyth m s,to nes,etc.t hat are unsignifiab l e yet an essentia l part of language.W it hout the sy m boli c,the se m iotic wo u l d be meaningless;w i tho ut the se m i2 oti c,t here woul d be no source and energy for the sy m boli c: /Bod il y m ove m en ts,process and energies provi de the sem iotic i m petus and ra w ma teria l s o u t of wh i ch the sy m bolic is for m ed.0[3]100W ithout the se m i oti c,t he sy m bolic is li ke a bag w it hout substance.The sem iotic i s both an i n tegra l part and a d i srupti ve f orce i n the language syste m.By ali gn i ng t he sy mbolic w it h t he se m i otic,K risteva does not m ean a si m ple co m b i na ti on of the t wo.R ather,it is a si gnifyi ng process tha t can resu lt i nto heterogene ity./Lacan.s li ngu i stic co ncept ua lizatio n of unco n2 sc i ous processes restricts access to essenti a l and hidden e l e m ents of exper i ence0[4]296,and K risteva reopens t h is access by t he theory of se m i oti c.2.3K risteva.s re-ret urning to F reudA s regards t he hetero geneous e le m en ts,Barzila i rety pes the key dense f oot note i n Kr isteva.s/M icrocos m0,i n wh i chK risteva rem inds us of the/i ncred i ble co mp l exity of F reud.s no2 ti on of-si gn.0[4]297t hat Lacan fa ils to take i n.F reud.s theory of/si gn0ackno w l edges t he hete rogeneous e le m en ts,because it not only conta i ns Lacan.s static ru l es i n S/s algor it h m but also invol ves the speak i ng sub j ect.s bodil y e l em ents tha t produce speech,such as the physiol ogica l aspects i n sound and t he mus2 cle m ove m ents.Desp ite of h is c lai m)/R eturn to F reud0) Lacan,by ove rsi m plifyi ng F reud,apparentl y depr i ves F reud of h i s m uch m ore co mp l ex and ori gina l concepti on of/s i gn0. Therefore,Kr i steva warns against i nd iscr i m i nate applica ti on of Lacan.s f or mu l a ti on t hat t h is oversi m p lificati on woul d result in the true castrati on of F reud.s or i gi na l d i scovery.W e shou l d keep i n m i nd t he i ncred i b l e co mp l exity of F reud.s noti on of a/sign0,wh i ch is exorbitant co mpared w ith the closure i m posed on t he si gn by Saussure.s stoi c is m.The F reud i an/sig n0i s o utli ned i n On A pha sia:vis ua,l tactile,and acoustic i m ages li nked to object assoc i a tions which re f e r,pr i nc i2 pa ll y throug h an aud i tory connecti on,to t he word itsel,f co m2 posed of an acoustic and k i nest hetic i m age,of read i ng and writ2 ing.The fact tha t the acoustic i m age is privil eged in this case does not d i m inish t he hete rogene ity of this/psychologi ca l blue2 pr i nt ofword-presenta tio ns,0wh i ch to daywe still have d ifficu l2 ty ass i m il a ting,even w it h the rigor of li nguisti cs and ana l yti ca l attenti veness.And yet,the nature of this/i m agery0will re m ain inco mprehensible unless we perce ive it as a l w ays a lready i ndebt2)39)LI TERAT URE Zhou Xueying/Recreating the Maternal and the Poetic Space:K risteva.s Critique of Lacaned(i n a more or less/pr i m ary0or/seco ndary0way,as he wo u l d later say)to that represen t-ab ilit y specific to lang uage, and t herefore to the li ngu i sti c sig n(si gn ifi er/si gn ifi ed).W hil e this s i gn serves as the i n ternal li m it upon wh ich F reud struct ures h i s notions of presen tati on and c l eavage(what Lacan m akes ex2 p licit in his/li ng hysteria0),it i s by no m eans the m ost far-reachi ng of F reud.s d isco veries.F reud.s concepti on of t he un2 consc i ous der i ves fro m a noti on of lang uage as both hetero geneo us and spatia,l outli ned first i n On A pha sia when he sketches out as a/to pol ogy0both the physi ol ogical underpinnings of speech (/t he territory of lang uage,0/a co n tinuo us cortical area,0/cen2 ters0seen as t hresholds,etc.)as we ll as l anguage acqu isiti on and co mmunicati on(t he after-word,the re l a ti on to the other).Ó.C on clusi onIn the process of civili za ti on,wo men are repressed by the m ale-do m i na ted society and forced to be mute and i nvi s i ble. The effecti ve cha ll enge of fem inists should be ach ieved not o n l y in ostensi ble politica l ri ghts of wo m en i n society as the first-wave fe m i n ists di d,but a lso m ore i m portantl y i n t he intell ec t ua l transfor m atio n of t he phall ocentr i c th i nk i ng.Kr i steva.s contr i bu2 ti on resi des i n her criti que of Lacan.s repress i ve sy m bolic order and her estab lish m ent of the m etaphysica l space for m a ternal dis2 course.H ence,Barzila iwrites i n the end of her essay:/No lo n2 ger s ilent onloo kers at the brother.s banquet,we co m e up to the tab le.And we a re hungry.0[4]304=Notes>¹Accordi ng t o Lacan,when t he i n f ant is born,it can.t tell the d ifference bet w een h i m se lf and the wor l d,that is to say,a sub2 ject hasn.t been bu ilt up yet.The i nfan t i n t h is phase enjo ys a perfect co mb i nati on with h is mot her.s body,bei ng content to be an appendage to itsm ot her,and w is h i ng to be m other.s/phal2lus0(desire object).Unfort una tely,fat her appea rs a t this ti m e, he breaks the chil d.s f antasy and f orces it to sepa ra te w it h its m other and take an appropriate place i n the soc iety.Then,under the pressure of fathe r.s la w,the infant is forced to regi ster hi m2 se lf i nto the gi ven soc i a l struct ure which cons i sts of d iffe rent i2 dentities and rol es.This structure,ter m ed as the sy mbolic order by Lacan,is constructed by l anguage based o n h i s S/s algorith m.ºBarzila im akes it clear t hat co ndensatio n i s ana lo gous but not identica l t o deco nstruc tion,because psychoana l yst is bo und by the duty of all evi a ti ng the pa i n of the suffer i ng pa ti ents wh ile f or deco nstructio n ists/t he questio n must be m a i nta i ned0(Barzila i 301),and t he sta rk polar izati on bet ween constructi on and co n2 densati on i s wha t Kr i steva woul d neve r concede.»A ccording to Kr isteva,despite of Lacan.s/fundamenta l re2 fi ne m en t0i n his theor izati on of language to wards his early state2 m ent)/The unconsc i ous i s structured li ke language0)Lacan still fa ils to acco unt f or the hetero geneo us ele m ents.=References>[1]Kr i steva,J u lia.Po wers of H orror:An Essay o n Ab jecti on[M].Trans.Leon S.R oud i e z.New York:Colu mb i aUn i versity Press,1982.[2]S m ith,Anne-M arie.Juli a Kr i steva:Speaki ng the Un2speakab le[M].Londo n and Ster ling,VA:P l u t o P ress.1998.[3]Grosz,E lizabe t h.The Body of S i gn ifi catio n[C]//AndrewBenja m i n.Abjecti on,M e l ancholia,and Love:The W ork of Juli a Kr isteva.New York:R outl edge,1990.[4]Barzila,i Shul.i Borders of Language:K risteva.s C ritiqueof Lacan[J].P MLA,1991,106(2).[5]Eagleton,Te rry.L itera ry Theory:An Intro ducti on[M].F oreign Language Teaching and R esearchi ng P ress,2004.女性空间和诗意空间)))克里斯蒂娃对拉康的批判周雪滢(北京外国语大学外国文学研究所,北京100089)[摘要]拉康批判美国式精神分析派的/自我心理学0,认为这样的精神分析学研究严重偏离了弗洛伊德的潜意识理论,把精神分析变成了一门实践科学。
The Formation of Coral Reefs and Atolls
The Formation of Coral Reefs and Atolls Coral reefs and atolls are some of the most fascinating and diverse ecosystems on the planet. They are formed from the accumulation of calcium carbonate exoskeletons of coral polyps, which are tiny, invertebrate animals that live in colonies. These structures provide a habitat for a wide variety of marine life, including fish, invertebrates, and algae. The formation of coral reefs and atolls is a complex process that involves geological, biological, and environmental factors.One of the key factors in the formation of coral reefs and atolls is the presence of suitable substrate for coral growth. Coral polyps require a hard surface on which to attach and grow, and they typically thrive in warm, shallow, clear waters. As the polyps grow and reproduce, they form colonies that eventually build up into large, solid structures. Over time, the accumulation of coral skeletons creates the framework for a reef or atoll.The geological processes that contribute to the formation of coral reefs and atolls are also important to consider. Reefs often form along the edges of continents or around volcanic islands, where the ocean floor is relatively shallow. As the Earth's tectonic plates shift and move, these areas can experience changes in sea level and land elevation, which can impact the growth and development of coral reefs. Additionally, the presence of ocean currents and wave action can influence the shape and structure of reefs, as well as the distribution of coral species.In addition to geological factors, biological processes play a crucial role in the formation of coral reefs and atolls. Coral polyps rely on a symbiotic relationship with photosynthetic algae called zooxanthellae, which live within their tissues and provide them with essential nutrients. This relationship allows corals to thrive in nutrient-poor waters, but it also makes them sensitive to environmental stressors such as changes in temperature and water quality. When corals are stressed, they can expel their zooxanthellae, a process known as coral bleaching, which can have devastating effects on reef ecosystems.The environmental conditions in which coral reefs and atolls form and grow are also significant. These ecosystems are typically found in tropical and subtropical regions, wherethe water is warm and clear. The availability of sunlight is crucial for the photosynthetic processes of both corals and their symbiotic algae, so reefs are most commonly found in shallow waters where light can penetrate. Additionally, the stability of water temperature and chemistry is important for the health and growth of coral reefs, as they are sensitive to changes in conditions such as ocean acidification and pollution.Human activities also play a role in the formation and degradation of coral reefs and atolls. Overfishing, destructive fishing practices, coastal development, and pollution can all have negative impacts on reef ecosystems. Additionally, climate change is a major threat to coral reefs, as rising sea temperatures and ocean acidification are causing widespread coral bleaching and mortality. Conservation efforts, such as marine protected areas and sustainable fishing practices, are essential for the preservation of these valuable and vulnerable ecosystems.In conclusion, the formation of coral reefs and atolls is a complex and dynamic process that involves a combination of geological, biological, and environmental factors. These ecosystems are not only incredibly diverse and beautiful, but they also provide important ecological and economic benefits. Understanding the processes that shape coral reefs and atolls is crucial for their conservation and management, especially in the face of growing threats from human activities and climate change. As stewards of the natural world, it is our responsibility to protect and preserve these irreplaceable ecosystems for future generations.。
飞鸟集(英语)
The fish in the water is silent, the ani mal on the earth is noisy, the bird in the air is singing. But man has in him the silence of the sea,the noise of the earth and the music of the air. 水里的游鱼是沉默的，陆地上的兽类 是喧闹的，空中的飞鸟是歌唱着 的。 但是，人类却兼有海里的沉默， 地上的喧闹与空中的音乐。
鸟翼上系上了黄金， 这鸟便永不能再在天 上翱翔了。
Stray birds of summer come to my window to sing and fly away. And yellow leaves of autumn,which have no songs,flutter and fall there with a sign.
夏天的飞鸟，飞到我的窗前唱歌，又飞去了。 秋天的黄叶，它们没有什么可唱， 只叹息一声，飞落在那里。
They throw their shadows before them who carry their lantern on their back.
那些把灯背在背上的人，把 他们的影子投到了自己前面。
We read the world wrong and say that it deceives us.
我们把世界看错了，反说它 欺骗我们。
If you shed tears when you miss the sun, you also miss the stars.
如果你因失去了太阳而流泪， 那么你也将失去群星了。
The introduction of Stray Birds
The ELAIS Deep X-ray Survey I Chandra Source Catalogue and First Results
a r X i v :a s t r o -p h /0207622v 2 1 A p r 2003Mon.Not.R.Astron.Soc.000,000–000(0000)Printed 1February 2008(MN L A T E X style file v2.2)The ELAIS Deep X-ray Survey I:Chandra Source Catalogue and First ResultsJ.C.Manners 1∗,O.Johnson 1,O.Almaini 1,C.J.Willott 2,E.Gonzalez-Solares 3,wrence 1,R.G.Mann 1,I.Perez-Fournon 4,J.S.Dunlop 1,R.G.McMahon 5,S.J.Oliver 3,M.Rowan-Robinson 6,S.Serjeant 71Institute for Astronomy,University of Edinburgh,Royal Observatory,Blackford Hill,Edinburgh EH93HJ 2Astrophysics,Department of Physics,Keble Rd,Oxford OX13RH3Astronomy Centre,CPES,University of Sussex,Falmer,Brighton,BN19QJ 4Instituto de Astrofisica de Canarias,38200La Laguna,Tenerife,Spain 5Institute of Astronomy,Madingley Road,Cambridge,CB30HA6Astrophysics Group,Blackett Laboratory,Imperial College,Prince Consort Rd,London SW72BW7Unit for Space Sciences and Astrophysics,School of Physical Sciences,University of Kent,Cantebury,CT27NZ∗Dipartimento di Astronomia,dell’Universita di Padova,Vicolo dell’Osservatorio,2-35122Padova,Italy as of October 2002MNRAS acceptedABSTRACTWe present an analysis of two deep (75ks)Chandra observations of the European Large Area ISO Survey (ELAIS)fields N1and N2as the first results from the ELAIS deep X-ray survey.This survey is being conducted in well studied regions with exten-sive multi-wavelength coverage.Here we present the Chandra source catalogues along with an analysis of source counts,hardness ratios and optical classifications.A total of 233X-ray point sources are detected in addition to 2soft extended sources,which are found to be associated with galaxy clusters.An over-density of sources is found in N1with 30%more sources than N2,which we attribute to large-scale structure.A similar variance is seen between other deep Chandra surveys.The source count statistics reveal an increasing fraction of hard sources at fainter fluxes.The number of galaxy-like counterparts also increases dramatically towards fainter fluxes,consistent with the emergence of a large population of obscured sources.Key words:surveys -catalogues -X-rays:general -X-rays:galaxies -X-rays:diffuse background -X-rays:galaxies:clusters -galaxies:active -quasars:general1INTRODUCTIONThe results of recent deep X-ray surveys reveal that almost the entire X-ray background can be resolved into discrete sources.The ROSAT Deep Survey (Hasinger et al.1998)resolved 70-80%of the 0.5-2keV background at a flux level of 1×10−15erg s −1cm −2.Observations with Chan-dra and XMM-Newton are now pushing the detection limits even further.In particular,the unprecedented resolution of Chandra allows extremely deep observations that are not limited by source confusion.This has been exploited in the Chandra Deep Fields (North,Brandt et al.2001,and South,Giacconi et al.2002).In the Chandra Deep Field-North 2Msec of data has been accumulated reaching a flux limit of ∼1.5×10−17erg s −1cm −2in the 0.5-2keV band (Barger et al.2003).However,the greatest advances have been at higher energies where Chandra is now beginning to resolve the 2-8keV background.The majority of sources resolved by ROSAT were foundto have spectra that were too steep to account for the flat spectrum of the hard X-ray background.However towards fainter fluxes a new population emerged in the ROSAT data with intrinsically harder X-ray spectra (Hasinger et al.1993,Almaini et al.1996).Chandra is now uncovering a large number of hard spectrum sources,and the majority of the 2-8keV background has been resolved.Over the flux range 2×10−16to 10−13erg s −1cm −2the contribution of resolved sources to the 2-8keV background is 1.1×10−11erg s −1cm −2deg −2(Cowie et al.2002).This translates to ∼65-85per cent of the background as measured by Vecchi et al.(1999,Beppo-Sax)and Ueda et al.(1999,ASCA)respec-tively.Early spectroscopic observations are finding a majority of the sources with hard X-ray spectra to be type II AGN,indicated by the presence of narrow lines (Tozzi et al.2001,Barger et al.2001a,Hornschemeier et al.2001).Most of these are found at z <1.However,a considerable fraction2J.Manners et al.of the hard X-ray sources are optically faint,probably due to obscuration,and provide challenging targets for spectro-scopic identification.Sources identified as type I AGN dis-play softer X-ray spectra and are observed to have a higher median redshift.There are still a number of unanswered questions relat-ing to the properties of the hard X-ray populations at longer wavelengths.AGN with large X-ray absorbing columns do not always appear as type II AGN in the optical(e.g. Maiolino et al.2001,Willott et al.2002).The relationship between gas and dust absorption in AGN remains unclear. It is also uncertain where the absorbed radiation may be re-radiated.Approximately∼7per cent of X-ray sources in the Chandra Deep Field North are sub-millimetre sources (Barger et al.2001b),however whether this is the result of reprocessed nuclear emission or due to a starburst compo-nent,is unknown.Almaini et al.(2003)find evidence for a strong angular cross-correlation between the X-ray and sub-millimetre populations.They suggests there may be an evolutionary sequence in these galaxies between the major episode of star-formation(sub-millimetre sources)and the onset of quasar activity(X-ray sources).To more fully un-derstand the nature of these sources will require in-depth multi-wavelength studies of the X-ray source population.We are conducting a deep X-ray survey with Chandra and XMM in two of the European Large Area ISO Survey (ELAIS)fields,N1and N2.These high latitudefields were chosen for their low cirrus emission,and have a wealth of multi-wavelength data available.Bothfields have been ob-served with ISO at7,15,90,and175µm(Oliver et al. 2000),with the VLA at1.4GHz(Ciliegi et al.1999,Ivi-son et al.2002),and have deep g′,r′,i′,H,and K imaging (Gonzalez-Solares et al.2003).Region N2has been mapped with SCUBA to8mJy at850µm(Fox et al.2001,Scott et al.2001).As well as the Chandra observations described here,XMM-Newton observations in region N1(5×30ksec pointings)are awaiting scheduling.In this paper we present the analysis of the Chandra X-ray data and the Chandra source catalogue.Paper II (Gonzalez-Solares et al.2003)will present details of the op-tical identifications.2THE X-RAY DATAThe ELAIS Deep X-ray Survey(EDXS)is being conducted in the northern ELAIS regions N1and N2.The Chandra data consists of approximately75ks exposures in eachfield. Region N1was observed on3-4August2000(OBSID887).The nominal aim-points were N1:16:10:20.11+54:33:22.3,and N2:16:36:46.99 +41:01:33.7.The ACIS-I chips were used with the addition of ACIS-S2and ACIS-S4.Analysis was carried out on data reprocessed with ver-sion R4CU5UPD14.1of the pipeline processing software. The data were reduced using the CIAO software package (version2.1).Bad pixels and columns were removed and data werefiltered to eliminate high background times.The latter was achieved through constructing a lightcurve for background regions and identifying periods of intense back-ground activity due to solarflares.One obviousflaring pe-riod was identified over the course of the observations result-ing in the removal of1552seconds from the data in region N1.More stringent conditions for the removal of high back-ground times were not thought necessary considering the low level of the quiescent background.Afterfiltering,exposures infields N1and N2were71.5ks and73.4ks respectively.Exposure maps were constructed to account for varia-tions in effective exposure across an image.This incorpo-rates the positions of bad pixels,dithering,and vignetting. The effective exposure is significantly affected by the en-ergy of the source counts.To account for this,an assumed source spectrum is convolved with the quantum efficiency of the chip and the effective area of the mirrors.The resulting map provides an estimate of the effective exposure(cm−2 s−1)at each point on the image.For our images,we used a power-law model spectrum,with photon indexΓ=1.7.3SOURCE DETECTIONSources were detected using a wavelet method,specifi-cally the W AVDETECT program(Freeman et al.2002)in-cluded with the CIAO software package.The“Mexican Hat”wavelet function is used,which consists of a positive core similar to a canonical PSF,surrounded by a negative an-nulus.The overall normalisation is zero.The zero-crossing point is at a radius of√2,4,4√2, 16,16√The ELAIS Deep X-ray Survey I3 counts were reinstated.Only sources obtained in the originalsource detection were used.W AVDETECT simulations(Freeman et al.2002)suggesta mean of1.0false sources will be detected over the regionof the4ACIS-I chips.We also impose a cut-offat a S/N of3.0,principally,for the purpose of defining aflux limit.Thishas the effect of removing a handful of the least significantsources,further improving the reliability of the sample.The detection efficiency of W AVDETECT is yet to bedefinitively determined.Early simulations have been doneby V.Kashyap(private communication)to determine theprobability of detecting sources of given strengths.In orderto gain an indication of the number of sources missing fromour list of detections,we have made crude extrapolations tothese simulations.These indicate that we detect∼98.5–99.5%of the sources with intrinsic strengths above the S/Nlimit of our sample.4THE CHANDRA SOURCE CATALOGUEA total of233X-ray sources have been detected in the2fields(Fig.1).In N1there are127sources in the full band(0.5-8keV),101in the soft band(0.5-2keV)including2extra sources not detected in the full band,and72sourcesin the hard band(2-8keV)including1extra source notdetected in the full band.There are57sources detected inboth the soft and hard bands.In N2there are98sources inthe full band,81in the soft band(including3extra sourcesnot in the full band),and52sources in the hard band(in-cluding2extra sources not in the full band).There are41sources detected in both the soft and hard bands.The IAU name for the catalogued sources is CXOEN1JHHMMSS.s+DDMMSS,for sources in N1(table1),andCXOEN2JHHMMSS.s+DDMMSS for sources in N2(table2).Coordinates are truncated to the above accuracy.Tables1&2display the full catalogue.Sources are de-tected to a S/N limit of3,defined as√S/N=C/(1+4J.Manners et al.-4-20246α02468F α / F 0.70.5 - 8 keV 0.5 - 2 keV 2 - 8 keVFigure 2.Conversion factors to calculate true flux for a source with spectral slope αgiven the fluxes quoted in the source cat-alogue (which assumes α=0.7).This figure has been calculated by passing model spectra of slope αthrough the total response matrix of the detector at a position corresponding to the source N123which lies 4.5arcmin from the fieldcentre.5SOURCE COUNTSIn this section we calculate the cumulative source counts,N(>S),and the differential source counts,n(S),in the three bands.We first outline details of the calculation (section 5.1)which requires knowledge of the available area of the survey as a function of flux.Section 5.2presents our results and comparisons with other surveys,while section 5.3describes our source contribution to the hard X-ray background.5.1Calculating source countsN(>S)is defined as the sum of the reciprocal areas avail-able for detecting each source that is brighter than flux S.It follows that n(S)is the sum of reciprocal areas per flux interval.The sky area over which a source of flux S may be observed depends on the flux limit at each point in the im-age.This,in turn,depends on the variation in PSF size and effective exposure across the image.The flux limit (S lim in erg cm −2s −1)may be defined by the chosen S/N limit of our sample (from equation 1):S/N lim =3=C lim /(1+√0.75+(B avg ×PSF size)The ELAIS Deep X-ray Survey I5-15.5-15.0-14.5-14.0-13.5-13.0log S X (ergs s -1cm -2)l o g N (>S ) (d e g -2)l o g N (>S ) (d e g -2)l o g N (>S ) (d e g -2)Figure 4.Cumulative number counts per square degree for sources detectedin the soft (top),hard (middle),and full (bot-tom)band images.Data are plotted as filled circles with solid lines enclosing 1σerrors.Number counts from other recent sur-veys are estimated from best-fitting power laws quoted in the above references.The full band plot includes the best-fit line to the differential counts for sources with S <10−13erg s −1cm −2.at our flux limit.At brighter fluxes the surveys differ by >2σ,most likely as a result of large-scale structure.The presence of clustering on these scales is well illus-trated by thedifference in the number counts observed in N1and N2(Fig.5).There are 30%more sources in N1than N2in the full band.In particular there is an overabundance of brighter sources in N1at a flux of (1−2)×10−14erg cm −2s −rge-scale structure is evident in the source im-log S X (0.5 - 2 keV) (ergs s -1 cm -2 )l o g N (>S ) (d e g -2 )Figure 5.Cumulative source counts (0.5-8keV band)for the survey fields N1&N2are over-plotted,illustrating the presence of clustering on scales larger than our field size.-15.0-14.5-14.0-13.5-13.0Normalised log S Xl o g N (>S ) (d e g -2 )Figure parison of the cumulative source counts for the combined fields in the soft and hard bands.The counts have been normalised to an equivalent full band flux (see text,section 5.2)to better emphasise the difference in slope between these popula-tions.ages (Fig.1),most noticeably as a dearth of sources in the centre of N2.Similar structure can also be seen in images of the Chandra Deep Field South (Giacconi et al.2001).An analysis of 9Chandra fields by Yang et al.(2003)has shown that such clustering is common in the Chandra source pop-ulation.A striking feature of the number count relations is the difference in slope between soft and hard band counts.Fig.6over-plots the soft and hard band counts normalised to an equivalent full band flux.Normalisation is done in order to plot both populations on the same flux scale and does not affect the slope of the number counts.The hard band sources are assumed to have hard spectra and so are arbitrarily nor-malised using an alpha of 0.The soft band sources are arbi-trarily normalised assuming a soft spectrum with an alpha of 1.The ratio of hard sources to soft sources is seen to increase dramatically towards fainter fluxes.This can be ex-plained through the mechanism of obscuration,which will6J.Manners et al.-15.5-15.0-14.5-14.0-13.5log S X (erg s -1 cm -2)141516171819l o g n (S ) (d e g -2 e r g -1 s c m 2)(0.5 - 2 keV)log n(S) = (-1.72 ± 0.09) log S - (8.0 ± 1.3)-15.0-14.5-14.0-13.5-13.0log S X (erg s -1 cm -2)141516171819l o g n (S ) (d e g -2 e r g -1 s c m 2)(2 - 8 keV)log n(S) = (-2.07 ± 0.15) log S - (12.5 ± 2.1)Cowie et al. 2002-15.0-14.5-14.0-13.5-13.0log S X (erg s -1 cm -2)141516171819l o g n (S ) (d e g -2 e r g -1 s c m 2)(0.5 - 8 keV)log n(S) = (-1.70 ± 0.08) log S - (7.4 ± 1.2)Figure 7.Differential number counts for sources detected in the soft (top),hard(middle),and full band (bottom)images.1σerror bars incorporate Poisson errors on the counts and the error on the available sky area.A weighted least-squares best fit is displayed with 1σerror ranges.act to harden the spectra while reducing the flux observed from X-ray sources.Differentialnumber counts per square degree per unit flux are plotted in Fig.7.Error bars display 1σerrors in-corporating Poisson errors on the counts and the error on the available sky area.The slope of the differential countslog S X (2 - 8 keV) (ergs s -1 cm -2)l o g X R B (>S ) (e r g s c m -2 s -1 d e g -2)Figure 8.Contribution to the hard X-ray background.The inte-grated hard band flux for sources fainter than 1×10−13erg cm −2s −1in this survey are plotted as filled circles.The contributions from other surveys are extrapolated from reported number count slopes.Plotted values for the total background exclude sources brighter than 1×10−13erg cm −2s −1.for each band was fitted with a power-law using a weighted least-squares fit.A single power-law was found to adequately fit the entire flux range for each of the three bands.For the 0.5-2keV band over the flux range (0.57-26)×10−15erg cm −2s −1we find:log n(S)=(−1.72±0.09)log S −(8.0±1.3)(6)For the 2-8keV band over the flux range (2.7-63)×10−15erg cm −2s −1we find:log n(S)=(−2.07±0.15)log S −(12.5±2.1)(7)For the 0.5-8keV band over the flux range (1.4-70)×10−15erg cm −2s −1we find:log n(S)=(−1.70±0.08)log S −(7.4±1.2)(8)The hard band differential counts are compared to a maximum likelihood fit from Cowie et al.(2002)to the com-bined counts from four deep fields (CDFN,CDFS,SSA22,&SSA13).These are found to be in good agreement with the error limits of our survey.5.3Contribution to the hard X-ray backgroundFig.8plots the integrated source flux for our survey (filled circles)for all sources with S <10−13erg cm −2s −1.At the flux limit of S 2−8=2.2×10−15erg cm −2s −1the resolved flux amounts to 8.5×10−12erg cm −2s −1deg −2.This is equivalent to between 50and 64%of the 2-8keV back-ground measured by Vecchi et al.(1999,Beppo-Sax)and Ueda et al.(1999,ASCA)respectively.To arrive at these values for the total background (as plotted in Fig.8)the contribution from sources with S >10−13erg cm −2s −1,as observed by ASCA (Della Ceca et al.1999),has been subtracted.The contribution to the background at fainter fluxes has been extrapolated from the source counts of the CDFN survey (Brandt et al.2001).By combining the re-sults of our survey with that of CDFN the contribution to the background within the flux range 10−13-6×10−16ergThe ELAIS Deep X-ray Survey I7-15.5-15.0-14.5-14.0-13.5-13.0log S X (0.5 - 2 keV) (ergs s -1 cm -2)l o g N (>S ) (d e g -2)Figure 9.Soft band number counts split between quasar-like,galaxy-like and unclassified (blank fields etc.)optical counter-parts.In comparison the QSOs observed with ROSAT (Boyle et al.1994)and associated models for the QSO X-ray luminosity function are over-plotted.cm −2s −1becomes 1.12×10−11erg cm −2s −1deg −2,equiva-lent to 66%and 84%of the aforementioned backgrounds.To compare the contributions from other surveys,we have used the best fit to the source counts as published by Mushotzky et al.(2000),and Giacconi et al.(2001,120ks exposure of CDFS).These have been normalised at the bright end using the number counts of ASCA sources from Della Ceca et al.(1999)to a bright limit of 10−13erg cm −2s −1.The observed discrepancy between the different surveys may be due to the effects of clustering on scales larger than the survey regions.6STAR/GALAXY CLASSIFICATIONDeep multicolour optical images have been obtained in both our fields,and will be discussed fully in Gonzalez-Solares et al.(2003).They have identified the optical counterparts of our X-ray sources in r ′band images with limiting mag-nitudes of ∼26.Source optical morphologies are classified according to agreement with a stellar point spread func-tion,as quantified in the SExtractor “stellarity”parameter,CLASS STAR (Bertin &Arnouts 1996).The output of a neural network classifier,the value of this parameter ranges from 0.0for significantly extended sources to 1.0for those with perfectly stellar PSFs.For our Chandra sample,we di-vide sources with quasar-like and galaxy-like counterparts at CLASS STAR =0.8.In practice,morphological classifica-tion is increasingly ambiguous for fainter sources with lower signal to noise and cannot be considered reliable near to the image limiting magnitude.A number of X-ray sources remain unclassified where they are associated with blank fields,gaps in the data,or are near to bright contaminating sources in the optical images.The cumulative soft-band sourcecounts for each group have been calculated and are plotted in Fig.9.At bright X-ray fluxes quasar-like sources are the most numerous.How-ever their number counts flatten appreciably below a flux of ∼5×10−15erg cm −2s −1.At fainter fluxes the fraction of galaxy-like sources dramatically increases.At the flux limitFlux (ergs s -1 cm -2)r / b a n d m a g n i t u d eFigure 10.X-ray flux vs.r ′band magnitude for Chandra sources.Symbols denote sources with galaxy-like morphology (open cir-cles),point-like morphology (closed circles),and ambiguous mor-phology (small stars),as well as spectroscopically confirmed stars (large stars)and spectroscopically confirmed Type II AGN (dia-monds).of 4.6×10−16erg cm −2s −1there are 35%more galaxy-like sources than quasar-like sources.An X-ray luminosity function (XLF)from Boyle et al.(1994)invoking pure luminosity evolution,was used to ob-tain number count predictions for broad-line AGN.This was based on observations of 107QSOs from a deep ROSAT sur-vey.These QSOs reached a flux limit of ∼5×10−15erg cm −2s −1in the 0.5-2keV band.We use their best fitting model (model S),with an exponential decline in the quasar population beyond z =2.7,to construct a prediction for the soft band QSO number counts.This is over-plotted in Fig.9(solid line)to compare with the cumulative number counts for sources with quasar-like optical IDs.The Boyle XLF also includes relatively low luminosity AGN which may possibly be resolved into galaxies in our r ′band images.A second model has therefore been added which excludes AGN with a 0.5-2keV luminosity less than 1043.5erg s −1(dotted line).The models are well matched to the data up to the flux limit of the ROSAT survey.However,beyond this they over-predict the number of quasar-like sources.In the limiting case where all the unclassified sources are stellar,the data becomes a good fit to the first model.In the more likely outcome that most of the unclassified objects are galaxies,the data may still be a reasonable fit to the Boyle XLF as long as a luminosity cut-offis applied.In Fig.10we plot full band X-ray flux vs.r ′band magni-tude for our Chandra sources (compare with Fig.3of Barger et al.2002,Fig.16of Giacconi et al.2002,Fig.6of Mainieri et al.2002).In this figure,as in those in section 7,we indi-cate source morphology only for sources with r ′<24,which have unambiguous classifications.Over-plotted are lines of constant X-ray to optical ratio,appropriate for the Sloan Gunn r ′filter:log(f X2.5(9)Among point-like sources optical luminosity is seen to scale with X-ray luminosity;nearly all exhibit X-ray to optical8J.Manners et al.Flux (ergs s -1 cm -2)HRFigure 11.Full band X-ray flux vs.HR for Chandra sources,with symbols as in Fig.10:filled circles are QSOs,open circles are galaxies,crosses are unclassified sources.The values indicated at right are the expected HR of absorbed power-law spectra at z =0,with various energy indices assuming galactic absorption,and with various absorbing columns assuming an unabsorbed power law of α=0.7.101010Flux (ergs s -1 cm -2)(H -S )/(H +S )Figure 12.Error-weighted average hardness ratio for sources of different morphology binned by flux,with symbols as in Fig.11.The number of sources in each bin are indicated,and the error bars indicate the variance within the bin.ratios,f X /fr ′,of 0.1to 10.In contrast,sources with galaxy-like morphology show no tight relation between X-ray and optical fluxes,suggesting that the host galaxies and not the central AGN dominate the optical emission.Four spectro-scopically confirmed Type II AGN (discussed fully in Willott et al.2002,Peres-Fournon et al.2002)are marked in Fig.10,only one of which has a notably high value of f X /fr ′.Of the six point-like sources with f X /fr ′<0.1,three are spectroscopically confirmed stars,as noted in the figure.7HARDNESS RATIOSBroad band X-ray hardness ratios were calculated for each source,and were defined as HR =(H −S )2,32,32√The ELAIS Deep X-ray Survey I9Figure13.This2.5x2.5arcmin r′-band image displays a clus-ter of galaxies which coincides with the extended X-ray sourceCXOEN2J163637.3+410804.The X-ray contours have been ob-tained by smoothing the Chandra data with a Gaussian of10arcsec.The X-ray position is centred on the brightest componentof the extended source.Figure14.ACIS-S pulse height spectrum of CXOEN2J163637.3+410804.The model is a Raymond-Smith emissionspectrum at the cluster redshift with0.3solar abundance,andyields a bestfit plasma temperature of2.73keV.The most significant of the2detected sources is CX-OEN2J163637.3+410804displayed in Fig.13.The X-rayposition(centred on the brightest component of the ex-tended source)is at J200016:36:37.38+41:08:04.9.Thereare207net source counts in the0.5-2keV band in an areacorresponding to a factor17.5larger than the PSF.Thisextrapolates to a soft bandflux of1.46±0.15×10−14ergcm−2s−1,although this includes theflux from point sourceN210J.Manners et al.of hard sources at fainterfluxes.The number of galaxy-like counterparts also increases dramatically towards fainter fluxes,consistent with the emergence of a large population of obscured sources.Additionally,objects with galaxy-like and faint optical counterparts exhibit harder X-ray spectra towards fainterfluxes,consistent with significant absorbing columns in this population.The source catalogues and further information regarding the ELAIS deep X-ray survey can be found at this URL: /∼jcm/edxs ACKNOWLEDGEMENTSJM acknowledges the support of a PPARC Studentship and would like to thank the IfA,Edinburgh for providing extra funds for the completion of this paper.REFERENCESAlmaini O.,Shanks T.,Boyle B.J.,Griffiths R.E.,Roche N.,Stew-art G.C.,&Georgantopoulos I.,1996,MNRAS,282,295 Almaini O.,Scott S.E.,Dunlop J.S.,Manners J.C.,Willott C.J., Lawrence A.,Ivison R.J.,Johnson O.,Blain A.W.,Pea-cock J.A.,Oliver S.J.,Fox M.J.,Mann R.G.,Perez-FournonI.,Gonzalez-Solares E.,Rowan-Robinson M.,Serjeant S.,Cabrera-Guerra F.,Hughes D.H.,2003,MNRAS,338,303 Barger A.J.,Cowie L.L.,Mushotzky 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The Chandra Observation of the IP TX Col
a r X i v :a s t r o -p h /0301646v 1 31 J a n 2003Magnetic Cataclysmic VariablesASP Conference Series,Vol.**VOLUME***,2003M.Cropper &S.VrielmannThe Chandra Observation of the IP TX ColEric M.SchlegelHarvard-Smithsonian Center for Astrophysics,60Garden St.,Cambridge,MA 02138USA Anandi SalinasUniversity of Texas at Austin,Austin,TX 78712USAAbstract.We present a preliminary look at the serendipitous observa-tion of the intermediate polar TX Col by Chandra .The ∼52ksec ob-servation is uninterrupted,providing an opportunity to disentangle the light curve and power spectra components.We illustrate the energy-dependence of the power spectrum.1.IntroductionTX Col is a 15-th mag object discovered by HEAO-1(Wood et al.1984)and recognized as an intermediate polar in 1985/6(Buckley et al.1985;Tuohy et al.1986).Its orbital period is 20,592sec with a spin period of ∼1910sec (Tuohy et al 1986;Mhlahlo et al.,these proceedings).2.Chandra ObservationTX Col was observed by Chandra on 2000July 26/27for ∼53ksec (observation identification number 914);the target was the cluster of galaxies Cl J0542.8-4100to measure the X-ray temperature function of clusters (e.g.,Ikebe et al.2002).The cluster was within 1′of the aimpoint,placing TX Col ∼6′.7arcmin off-axis on CCD 1of the ‘imaging’portion of the ACIS detector.Figure 1shows the Chandra field-of-view showing that 5ACIS CCDs were active during the observation.TX Col and the galaxy cluster are indicated.The estimated count rate was ∼0.57counts s −1with a background rate of 0.006counts s −1.Both values were obtained by extracting the counts in circles of radii 0.3and 1arcmin,respectively.The background circle was displaced from the position of TX Col by ∼2′because TX Col falls sufficiently close to the edge of the CCD that ∼half of an annulus centered on TX Col’s position would have extended beyond the chip’s edge.A narrow rectangular region was excluded from the outer portions of the TX Col extraction to eliminate the presence of the frame transfer events.The off-axis angle reduces the effects of event pileup (Davis 2001).The streak caused by the frame transfer determines the position of TX Col along the CCD columns.We adopted the peak number of events on that line as the12Schlegel &SalinasFigure 1.Chandra ACIS field-of-view of TX Col.N ETX ColCl J0542.8−4100:10:05:55:50−41:0005 :4305 :42center of the observed point spread function.We extracted a radial profile using 21elliptical annuli spread across ∼21pixels (∼10′′.5);a theoretical point spread function was generated from the Chandra PSF library at the observed off-axis angle.The two functions agreed to better than 5%in the core of the profile and indicated that pileup is at most a minor component of the TX Col observation.3.Light CurvesWe filtered the events into three energy bands:0.5-1.5,1.5-4,and 4-8keV in an effort to separate the high energy source emission and the low-energy absorption.The middle band served simply to permit defining a color.We extracted the events and binned them into 20bins folded on the spin period of 1910sec.We arbitrarily adopted the time of the first Chandra event as the starting point for the phasing for this preliminary analysis.Figure 2shows the result.The zero point is incorrect by ∼0.5in phase (depending upon how one defines the ‘peak’).The soft band shows a humped behavior approximately symmetric about the maximum.The medium band shows a steeper rise to maximum with a gradual fall.The hard band is flattened with perhaps a steep rise just after phase 0.0.Figure 3(top)shows the complete ACIS light curve,∼52ksec or ∼26spin cycles in length.We can easily count the spin cycles,but note that the envelope of the amplitudes changes significantly across the observation.Figure 3(bottom)expands a portion of the full light curve to show the significant changes in amplitude among individual spin cycles.APS Conf.Ser.Style 3Figure 2.Energy-filtered light curves folded at the spin period of TXCol.0.005.01.015.02C o u n t R a t e0.5-1.5 keVTX Col-Chandra0.005.01.015.02C o u n t R a t e1.5-4 keV.511.520.002.004.006.008.01Spin PhaseC o u n t R a t e4-8 keV4Schlegel &SalinasFigure 3.The complete Chandra ACIS light curve.About 26indi-vidual spin cycles are visible in this observation.Note the amplitude variations across the observation.(top)the full observation;(bottom)a portion expanded.The bins are 100sec in size.01000020000300004000050000.2.4.6.811.2C o u n t s /s e cTX Col400004500050000.2.4.6.811.2Time (sec) from LaunchC o u n t s /s ecAPS Conf.Ser.Style5 4.Power SpectraPower spectra were computed in the three energy bands for the entire observation as well as across the entire ACIS bandpass for subsets of the observation.There are insufficient events to examine power spectra of energy-filtered subsets.The power spectra illustrate differences in amplitudes of the various com-ponents as a function of energy.The spin frequency is the dominant component in the soft and medium bands,but at the highest energies,theω−Ωcompo-nent dominates.Also visible is significant power at the half-integer frequencies, particularly near8.2×10−4Hz,suggesting the presence of a2ω−9Dateωω+Ω2ω−2ΩASCA√××? ROSAT√√√√Chandra√√√√6Schlegel &SalinasFigure 4.Energy-filtered power spectra of TX Col using the three energy band definitions indicated on the figure.The vertical dashed lines indicate the positions of the |mω±n Ω|for (m,n)=(0,1,2).Note that the vertical scale changes for the 4-8keV band.Also note the dominance of the ω−Ωcomponent in that band.02040P o w e rTX Col: 0.5-1.5 keV02040P o w e r1.5-4 keV.0005.001.0015.002-20246810FrequencyP o w e r4.0-8.0 keVAPS Conf.Ser.Style 7Figure 5.Power spectrum from the (top)first ‘orbit’and from the (bottom)‘second’orbit.Note that the ω−Ωcomponent is essentially missing from the second orbit.This figure replaces one shown at the meeting (the ‘half-orbit’approach),but the results are insignificantly different.0.0005.001.0015.002.002.004.006.008.01P o w e rTX Col: Orbit 1.0005.001.0015.002.002.004.006.008.01FrequencyP o w e rTX Col: Orbit 2。
托福阅读机经训练：拉斯科岩洞画
托福阅读机经训练：拉斯科岩洞画Lascaux Cave PaintingsIn Southwest France in the 1940’s, playing children discovered Lascaux Grotto, a series of narrow cave chambers that contain huge prehistoric paintings of animals. Many of these beasts are as large as 16 feet (almost 5 meters). Some follow each other in solemn parades, but others swirl about, sideways and upside down. The animals are bulls, wild horses, reindeer, bison, and mammoths outlined with charcoal and painted mostly in reds, yellow, and browns. Scientific analysis reveals that the colors were derived from ocher and other iron oxides ground into a fine powder. Methods of applying color varied: some colors were brushed or smeared on rock surfaces and others were blown or sprayed. It is possible that tubes made from animal bones were used for spraying because hollow bones, some stained with pigment, have been found nearby.One of the most puzzling aspects of the paintings is their location. Other rock paintings—for example, those of Bushmen in South Africa—are either located near cave entrances or completely in the open. Cave paintings in France and Spain, however, are in recesses and caverns far removed from original cave entrances. This means that artists were forced to work in cramped spaces and without sources of natural light. It also implies that whoever made them did not want them to be easily found. Since cave dwellers normally lived close to entrances, there must have been some reason why so many generations of Lascaux cave dwellers hid their art.Scholars offer three related but different opinions about the mysterious origin and significance of these paintings. One opinion is that the paintings were a record of seasonal migrations made by herds. Because some paintings were made directly over others, obliterating them, it is probable that a painting’s value ended with the migration it pictured. Unfortunately, this explanation fails to explain the hidden locations, unless the migrations were celebrated with secret ceremonies.Another opinion is that the paintings were directly related to hunting and were an essential part of a special preparation ceremony. This opinion holds that the pictures and whatever ceremony they accompanied were an ancient method of psychologically motivating hunters. It is conceivable that before going hunting the hunters would draw or study pictures of animals and imagine a successful hunt. Considerable support exists for this opinion because several animals in the pictures are wounded by arrows and spears. This opinion also attempts to solve the overpainting by explaining that an animal’s picture had no further use after the hunt.A third opinion takes psychological motivation much further into the realm of tribal ceremonies and mystery: the belief that certain animals assumed mythical significance as ancient ancestors or protectors of a given tribe or clan. Two types of images substantiate this theory: the strange, indecipherable geometric shapes that appear near some animals, and the few drawings of men. Wherever men appear they are crudely drawn and their bodies are elongated and rigid. Some men are in a prone position and some have bird or animal heads. Advocates for this opinion point to reports from people who have experienced a trance state, a highly suggestive state of low consciousness between waking and sleeping. Uniformly, these people experienced weightlessness and the sensation that their bodies were being stretched lengthwise. Advocates also point to people who believe that the forces of nature are inhabited by spirits, particularly shamans* who believe that an animal’s spirit and energy is transferred to them while in a trance. One Lascaux narrative picture, which shows a man with a birdlike head and a wounded animal, would seem to lend credence to this third opinion, but there is still much that remains unexplained. For example, where is the proof that the man in the picture is a shaman? He could as easily be a hunter wearing a headmask. Many tribal hunters, including some Native Americans, camouflaged themselves by wearing animal heads and hides.Perhaps so much time has passed that there will never be satisfactory answers to the cave images, but their mystique only adds to their importance. Certainly a great art exists, and by its existence reveals that ancient human beings were not without intelligence, skill, and sensitivity.Shamans: holy people who act as healers and divinersParagraph 1: In Southwest France in the 1940’s, playing children discovered Lascaux Grotto, a series of narrow cave chambers that contain huge prehistoric paintings of animals. Many of these beasts are as large as 16 feet (almost 5 meters). Some follow each other in solemn parades, but others swirl about, sideways and upside down. The animals are bulls, wild horses, reindeer, bison, and mammoths outlined with charcoal and painted mostly in reds, yellow, and browns. Scientific analysis reveals that the colors were derived from ocher and other iron oxides ground into a fine powder. Methods of applying color varied: some colors were brushed or smeared on rock surfaces and others were blown or sprayed. It is possible that tubes made from animal bones were used for spraying because hollow bones, some stained with pigment, have been found nearby.1. The word “others”in the passage refers to(3)○chambers○paintings○beasts○parades2. The word “Methods”in the passage is closest in meaning to(1)○Ways○Shades○Stages○Rules3. What are the bones found in the Lascaux caves believed to indicate? (4)○Wild animals sometimes lived in the cave chambers.○Artists painted pictures on both walls and bones.○Artists ground them into a fine powder to make paint.○Artists developed special techniques for painting the walls.Paragraph 2: One of the most puzzling aspects of the paintings is their location. Other rock paintings—for example, those of Bushmen in South Africa—are either located near cave entrances or completely in the open. Cave paintings in France and Spain, however, are in recesses and caverns far removed from original cave entrances. This means that artists were forced to work in cramped spaces and without sources of natural light. It also implies that whoever made them did not want them to be easily found. Since cave dwellers normally lived close to entrances, there must have been some reason why so many generations of Lascaux cave dwellers hid their art.4. Why does the author mention Bushmen in South Africa in paragraph 2? (2)○To suggest that ancient artists from all over the world painted animals on rocks○To contrast the location of their rock paintings to those found at Lascaux○To support the claim that early artists worked in cramped spaces○To give an example of other artists who painted in hidden locations5. What can be inferred from paragraph 2 about cave painters in France and Spain? (3)○They also painted rocks outside caves.○They did not live close to the cave entrances.○They developed their own sources of light to use while painting.○Their painting practices did not last for many years.Paragraph 3: Scholars offer three related but different opinions about the mysterious origin and significance of these paintings. One opinion is that the paintings were a record of seasonal migrations made by herds. Because some paintings were made directly over others, obliterating them, it is probable that a painting’s value ended with the migration it pictured. Unfortunately, this explanation fails to explain the hidden locations, unless the migrations were celebrated with secret ceremonies.6. Why does the author mention secret ceremonies?(3)○To present a common opinion held by many scholars○To suggest a similarity between two opinions held by scholars○To suggest a possible explanation for a weakness in an opinion expressed in the passage○To give evidence that contradicts a major opinion expressed in the passageParagraph 4: Another opinion is that the paintings were directly related to hunting and were an essential part of a special preparation ceremony. This opinion holds that the pictures and whatever ceremony they accompanied were an ancient method of psychologically motivating hunters. It is conceivable that before going hunting the hunters would draw or study pictures of animals and imagine a successful hunt. Considerable support exists for this opinion because several animals in the pictures are wounded by arrows and spears. This opinion also attempts to solve the overpainting by explaining that an animal’s picture had no further use after the hunt.7. The word “accompanied”in the passage is closest in meaning to(3)○represented○developed into○were associated with○came after8. According to paragraph 4, why do some scholars believe that the paintings were related to hunting? (3)○Because some tools used for painting were also used for hunting○Because cave inhabitants were known to prefer animal food rather than plant food○Because some of the animals are shown wounded by weapons○Because many hunters were also typically paintersParagraph 5: A third opinion takes psychological motivation much further into the realm of tribal ceremonies and mystery: the belief that certain animals assumed mythical significance as ancient ancestors or protectors of a given tribe or clan. Two types of images substantiate this theory: the strange, indecipherable geometric shapes that appear near some animals, and the few drawings of men. Wherever men appear they are crudely drawn and their bodies are elongated and rigid. Some men are in a prone position and some have bird or animal heads. Advocates for this opinion point to reports from people who have experienced a trance state, a highly suggestive state of low consciousness between waking and sleeping. Uniformly, these people experienced weightlessness and the sensation that their bodies were being stretched lengthwise. Advocates also point to people who believe that the forces of nature are inhabited by spirits, particularly shamans* who believe that an animal’s spirit and energy is transferred to them while in a trance. One Lascaux narrative picture, which shows a man with a birdlike head and a wounded animal, would seem to lend credence to this third opinion, but there is still much that remains unexplained. For example, where is the proof that the man in the picture is a shaman? He could as easily be a hunter wearing a headmask. Many tribal hunters, including some Native Americans, camouflaged themselves by wearing animal heads and hides.9. According to paragraph 5, why do some scholars refer to a trance state to help understand the cave paintings? (4)○To explain the state of consciousness the artists were in when they painted their pictures○To demonstrate the mythical significance of the strange geometric shapes○To indicate that trance states were often associated with activities that took place inside caves○To give a possible reason for the strange appearance of the men painted on the cave walls10. According to paragraph 5, if the man pictured with the birdlike head is not a shaman, he may have worn the headmask (1)○to look like an animal while a hunt took place○to frighten off other hunters competing for food○to prove that he is not a shaman○to resist forces of nature thought to be present in animalsParagraph 6: Perhaps so much time has passed that there will never be satisfactory answers to the cave images, but their mystique only adds to their importance. Certainly a great art exists, and by its existence reveals that ancient human beings were not without intelligence, skill, and sensitivity.11. According to paragraph 6, why might the puzzling questions about the paintings never be answered?(3)○Keeping the paintings a mystery will increase their importance.○The artists hid their tools with great intelligence and skill.○Too many years have gone by since the images were painted.○Answering the question is not very important to scholars.Paragraph 2: One of the most puzzling aspects of the paintings is their location. Other rock paintings—for example, those of Bushmen in South Africa—are either located near cave entrances or completely in the open. █Cave paintings in France and Spain, however, are in recesses and caverns far removed from original cave entrances. █This means that artists were forced to work in cramped spaces and without sources of natural light. █It also implies that whoever made them did not want them to be easily found. █Since cave dwellers normally lived close to entrances, there must have been some reason why so many generations of Lascaux cave dwellers hid their art.12. Look at the four squares [■] that indicate where the following sentence could be added to the passage.(1)This made it easy for the artists to paint and display them for the rest of the cave dwellers.Where would the sentence best fit?13. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.Scholars have wondered about the meaning of the subjects, location, and overpainting of Lascaux cave images.●The paintings may have…●It is possible that the animals…●Some scholars believe that…Answer Choices○The paintings may have recorded information about animal migrations, and may only have been useful for one migration at a time.○The human figures represented in the paintings appear to be less carefully shaped than those of animals.○It is possible that the animals in the paintings were of mythical significance to the tribe, and the paintings reflected an important spiritual practice.○Unlike painters of the recently discovered paintings, other Lascaux cave painters usually painted on rocks near cave entrances or in open spaces outside the caves.○Some scholars believe that the paintings motivated hunters by allowing them to picture a successful hunt.○Scientific analysis suggests that paintings were sprayed onto the rock walls with tubes made from animal bones.参考答案：1. ○32. ○13. ○44. ○25. ○36. ○37. ○38. ○39. ○410. ○111. ○312. ○113. The paintings may have…It is possible that the animals…Some scholars believe that…参考译文：拉斯科岩洞画在二十世纪四十年代的法国的西南部，玩耍中的孩子们发现了拉斯科岩洞，一系列狭窄的洞穴室内含有庞大的史前动物题材绘画。
枯枝咏叹调英文名
枯枝咏叹调英文名English Name for "枯枝咏叹调": "Elegy for Withered Branches"Introduction:"Elegy for Withered Branches" is a beautiful and evocative poetic composition that captures the melancholic essence of nature's decay. This elegy encapsulates the profound emotions and reflections inspired by the sight of withered branches, symbolizing the transience of life and the inevitability of mortality. In this article, we will explore the themes and symbolism of "枯枝咏叹调," while also delving into the significance of elegies in English literature.The Themes of "Elegy for Withered Branches":"Elegy for Withered Branches" is an introspective piece that revolves around the themes of transience, decay, and the passage of time. The imagery of withered branches serves as a metaphor for the fragile and ephemeral nature of human existence. Through the observation of nature's decay, the poet contemplates the fleeting nature of life, reminding readers of the inevitability of mortality. This elegy serves as a poignant reminder to appreciate the beauty and significance of life while we can.Symbolism in "Elegy for Withered Branches":Symbolism plays a crucial role in "Elegy for Withered Branches," as the poet employs various elements to convey deeper meanings. The withered branches symbolize the gradual decline and eventual demise of life, reminding us of the impermanence of all things. Additionally, the barren landscape signifies the passing of seasons and the cyclical nature of life, where death and rebirth are intertwined. The elegy's somber tone and introspective mood further emphasize the poet's contemplation of the fragility of existence.The Significance of Elegies in English Literature:Elegies have long held a significant place in English literature, with notable examples including Thomas Gray's "Elegy Written in a Country Churchyard" and Alfred, Lord Tennyson's "In Memoriam A.H.H." Elegies provide a space for contemplation, grief, and reflection, allowing poets to express their emotions and thoughts on mortality, loss, and the human condition. These mournful and reflective compositions often offer solace and comfort to readers, allowing them to explore their own feelings of melancholy and find solace in shared experiences."Elegy for Withered Branches" and the Power of Nature:Nature has always been a powerful source of inspiration for poets, and "Elegy for Withered Branches" exemplifies this connection. The poet draws on the beauty and decay of the natural world to evoke a sense of longing, melancholy, and contemplation. The withered branches become a visual representation of the fragility of life and the inevitability of death. Through the power of nature's imagery, the elegy explores the human condition and offers a profound reflection on the transience of existence.Conclusion:"Elegy for Withered Branches," also known as "枯枝咏叹调," is a poignant and introspective elegy that delves into the themes of transience, decay, and the passage of time. Through the symbolism of withered branches, the poet invites readers to contemplate the fragility of life and the inevitability of mortality. This elegy serves as a reminder to appreciate the beauty and significance of existence, while also reflecting on the power of nature to evoke deep emotions and introspection.。
肺部的等温饱和界面
肺部的等温饱和界面英文回答：The isothermal saturation interface in the lungs refers to the boundary between the gas phase and the liquid phase in the alveoli. It is a crucial interface that plays a significant role in maintaining the proper functioning of the respiratory system.When we inhale, the air enters the lungs and reaches the alveoli, which are tiny air sacs. The air in thealveoli is in contact with the thin layer of liquid that lines the alveolar walls. This liquid is known as the pulmonary surfactant, and it helps to reduce the surface tension within the alveoli, allowing them to expand and facilitate gas exchange.At the isothermal saturation interface, the inhaled air becomes saturated with water vapor from the liquid phase. This process is essential for humidifying the air andensuring that it is at the right temperature and moisture level before it reaches the deeper parts of the respiratory system.The isothermal saturation interface is maintained through various mechanisms. One of them is the presence of the pulmonary surfactant, which prevents the alveolar walls from collapsing by reducing surface tension. Another mechanism is the regulation of temperature and humidity within the respiratory system, which helps to ensure that the air is properly conditioned before it reaches the alveoli.To illustrate the importance of the isothermal saturation interface, let's consider an example. Imagine you are running on a cold winter day, and you start breathing heavily. As you inhale, the cold air enters your lungs and comes into contact with the warm liquid lining the alveoli. At the isothermal saturation interface, the cold air gets warmed up and humidified, making it more comfortable for your respiratory system. Without this interface, the cold air would directly reach the deeperparts of your lungs, potentially causing discomfort or irritation.中文回答：肺部的等温饱和界面是指肺泡中气相和液相之间的边界。
朱自清荷塘月色英文版
朱自清荷塘月色英文版IntroductionThe essay “荷塘月色” (Moonlight over the Lotus Pond) by Zhu Ziqing is a timeless masterpiece in Chinese literature. Through vivid descriptions and lyrical language, Zhu Ziqing transports the readers into the serene world of a lotus pond bathed in moonlight. This essay not only captures the beauty of nature but also reflects the poet’s inner thoughts and emotions. In this article, we will explore the enchanting charm of “荷塘月色” and delve into the deeper meaning behind Zhu Ziqing’s words.A Glimpse of the Lotus PondThe moonlight over the lotus pond is a sight to behold. As Zhu Ziqing vividly describes in his essay, the lotus flowers are in full bloom, their delicate petals reflecting the silvery moonlight. The pond is calm and still, mirroring the sky above like a perfectly polished mirror. The gentle breeze rustles the leaves of the lotus plants, adding a touch of ethereal beauty to the scene. In the midst of this tranquil setting, the moon casts a soft glow, illuminating the entire pond with its radiant light.The Reflection of the MoonIn “荷塘月色,” Zhu Ziqing marvels at the reflection of the moon in the lotus pond. He compares the moon in the sky to a silver plate suspended in mid-air, while the reflection in the water appears like molten silver flowing down from above. The mirror-like surface of the pond reflects the moon with such precision that it becomes difficult to discern the real moon from its reflection. This imagery symbolizes the interplay between reality and illusion, where the line between what is real and what is perceived becomes blurred.Contemplation under MoonlightAs Zhu Ziqing walks along the banks of the lotus pond, he finds solacein the tranquillity of the night. Under the moonlight, he is able to escape from the complexities of daily life and immerse himself in a state of serene contemplation. He ponders upon the ephemeral nature of life, likening the lotus flowers that bloom and wither to the passing moments that make up our existence. The moon, in its eternal cycle, becomes a symbol of time, reminding us of the constant flux of life.Connection with NatureIn his essay, Zhu Ziqing expresses a deep connection with nature. The lotus pond, with its delicate beauty and serene atmosphere, becomes a sanctuary for the poet’s soul. He finds solace and peace in the har mony of the natural world, away from the chaos and noise of the modern world. This connection with nature serves as a reminder of our essential human nature and the need to seek balance and tranquillity in our lives.Appreciating the Simple PleasuresThrou gh “荷塘月色,” Zhu Ziqing invites us to appreciate the simple pleasures that surround us. He finds joy in the subtle beauty of the lotus flowers, the calmness of the pond, and the gentle moonlight. By immersing ourselves in these small moments of beauty, we can find contentment and happiness. Zhu Ziqing’s essay encourages us to slow down and pay attention to the often-overlooked wonders of the world around us.Conclusion“荷塘月色” is not just an essay about the moonlight over a lotus pond. It is a reflection on the beauty of nature, the passage of time, and the importance of finding peace and tranquillity in our lives. Zhu Ziqing’s lyrical language and vivid descriptions transport us into the enchanting world of the lotus pond. As we read his words, we are reminded of the profound connection between humans and nature, and the need to appreciate the simple joys that surround us. The moonlight over thelotus pond serves as a gentle reminder to slow down, contemplate, and find solace in the beauty of the world.。
电子文献的著录规则
红色文化的历史逻辑与现实价值红色文化是中国革命文化的一部分，涵盖了中国革命的历史、思想、艺术、文学等方面。
它是中国革命历史的重要见证和精神遗产，具有丰富的历史内涵和广泛的社会影响，同时也具有深刻的现实意义和价值。
本文将从红色文化的历史逻辑和现实价值两个方面进行探讨。
一、红色文化的历史逻辑1. 革命历史的见证红色文化承载着中国革命历史的重要见证。
在中国革命的各个历史阶段，不同形式的红色文化都有着独特的历史价值。
比如在辛亥革命时期，以《义勇军进行曲》等为代表的革命歌曲成为了中国社会进步的精神旗帜；在土地革命时期，延安文艺座谈会等红色文化活动成为了中国革命文化的重要标志；在抗日战争和解放战争时期，以《东方红》等为代表的革命歌曲和红色电影等作品激励了全国人民的斗志。
红色文化见证了中国革命的曲折与艰辛，反映了中国人民为自由和幸福所作出的巨大牺牲和努力。
2. 精神遗产的传承红色文化也是中国革命精神遗产的传承者。
红军长征、延安精神、抗日英雄等都成为了中国人民的精神符号，激励着后人永远不忘初心，牢记使命。
这种精神遗产的传承，使红色文化得以延续，并在当今社会产生深远的影响。
中国革命的理想与信念，革命者的无私奉献精神，都在红色文化中得到了体现和传承，为新时代的中国社会注入了强大的正能量。
3. 社会历史的反思红色文化是对中国社会历史的反思。
在中国革命的历史过程中，红色文化涌现出大量有深刻社会思想基础的文艺作品和思想文化成果，不仅提供了对社会现实的批判和反思，也为中国的社会革命和变革提供了理论和实践的依据。
红色文化中的精神和思想，反映了中国革命者对社会发展的探索和思考，为当代中国社会的发展和进步提供了宝贵的历史经验。
二、红色文化的现实价值1. 增强国家认同红色文化可以增强国家认同，凝聚民族精神。
中国是一个拥有着悠久历史和丰富文化的民族，而红色文化作为中国革命文化的一部分，能够唤起人们对国家的认同和归属感。
在当今社会，弘扬红色文化，激发人们对国家和民族的热爱和自豪感，有利于增强国家凝聚力和社会稳定。
The Wonders of the Tundra
The Wonders of the Tundra The tundra is a unique and fascinating ecosystem that is often overlooked in discussions about the natural world. This vast, treeless biome covers asignificant portion of the Earth's surface, stretching across the Arctic regions of North America, Europe, and Asia. Despite its harsh climate and sparse vegetation, the tundra is home to a diverse array of plant and animal species that have adapted to survive in this challenging environment. One of the most striking features of the tundra is its stark, barren landscape. The ground is typically covered in a layer of permafrost, a thick layer of frozen soil that remains frozen year-round. This frozen ground makes it difficult for plants to establish deep root systems, leading to the characteristic low-growing vegetation found in the tundra. Mosses, lichens, and small shrubs are common in this biome, providing food and shelter for a variety of animals. Despite its seemingly desolate appearance, the tundra is teeming with life. Many species of migratory birds travel to the tundra each year to breed and raise their young. These birds take advantage of the long days of the Arctic summer, when the sun never sets, to feed and care fortheir offspring. Some of the most iconic tundra birds include the snowy owl, the Arctic tern, and the tundra swan. In addition to birds, the tundra is also home to a variety of mammals that have adapted to survive in this harsh environment. Species such as the Arctic fox, the musk ox, and the caribou are well suited to the cold temperatures and limited food sources of the tundra. These animals have thick fur coats and specialized diets that allow them to thrive in this challenging biome. One of the most fascinating aspects of the tundra is its role in the global climate system. The tundra acts as a carbon sink, storing vast amounts of carbon in its frozen soil. However, as the climate warms and the permafrost thaws, this stored carbon is released into the atmosphere, contributing to global warming. This feedback loop, known as the permafrost carbon feedback, is a major concern for scientists studying the impacts of climate change on the Arctic. Despite the challenges facing the tundra, there is still much to be learned and appreciated about this unique ecosystem. By studying the plants, animals, and geological features of the tundra, scientists can gain valuable insights into how ecosystems respond to environmental change. In addition, byraising awareness about the importance of protecting the tundra, we can help ensure that this fragile biome remains intact for future generations to enjoy. In conclusion, the tundra is a remarkable and awe-inspiring ecosystem that deserves our attention and respect. From its stark beauty to its vital role in the global climate system, the tundra is a place of wonder and discovery. By learning more about this unique biome and working to protect it, we can help ensure that the wonders of the tundra continue to inspire and captivate us for generations to come.。
世界各地各式教堂解读
Chapel Notre-Dame-du-Haut de Ronchamp. Designed by the architect Le Corbusier, considered one of the most important of the century XX. The windows in the thick and curved walls let in a weak and indirect light. The previous church was destroyed during the second world war but a part of the ruins was used by the architect.Cathedral of Our Lady of the Glory, Maringá, in the State of the Paraná, Brazil. Modern and bold architecture idealized by D.jaime Luiz Rabbit and Designed by the architect José Augusto Bellucci, inspired by the satellite Sputnik. The cone has an external height of114 m, supporting a cross of 10 m. It has capacity to shelter3.500 people.Lutheran Church in Reykjavik, Iceland. It took 38 years to build. Took the name of the priest and Icelandic poet Allgrímur Pétursson. With 74.5m of height, it is a fine example of architectural structure of Iceland.Church of Saint's Agostinho in Paoay, Philippines. Built between 1704 and 1894. Oriental and baroque influence. Located in an area with earthquakes, it was built with walls 1.67m thick.The Cathedral of Milan, Italy. The construction began in 1386 and took 200 years to be completed. An immense Gothic construction from white marble, it’s 1577 m in length, it accommodates up to 40,000 people in the interior.Brasilia Cathedral, in the capital of Brazil. Modern construction, of Oscar Niemeyer one of the most important architects of the present time. It has a circular area of 70 m of whose diameter there are lifted up 16 columns of concrete, which weigh 90 tons. The inauguration was in 1970,St.Basílio Cathedral, located in Red Square in Moscow.Church located in a parish of Buenos Aires, Argentina.Catholic Ukrainian cathedral of Saint José in Chicago. The golden domes symbolize twelve apostles and Jesus Christ. It was finished in 1956. The interior is completely decorated in Byzantine style.In the towns of Torpo and Borgund, in Norway. It dates from 1180 and is considered one of the symbols of NorwayCathedral of Our Lady of Las Lajas, Colombia. Built between 1916 and 1949 on two arches, in the river Canyon Guaitara. It is considered one of the wonders of Colombia..Rustic church located along the Fortress Kalemegdan in Belgrade, Serbia. It is a small chapel.The space was used by the Turks to warehouse gunpowder for more than a hundred years. It was rebuilt in 1920.The Church of Paraportianíis in MyKonos, Greece.The name means " secondary gate " because it was built with stone inthe place of one of the gates of the medieval walls. The construction was initiated in 1425.Cathedral of Rio de Janeiro Brazil. Built between 1964 and 1979.Chapel of St Michael of Ainguilhe, in Puy Velay, in France. It was built in the year 962 on a volcanic stone, for the Bishop Gothescalk after the return of a pilgrimage for Santiago of Compostella. In 1955, in an hidden area, the workers found many relics under the altar. In 1429 the mother of Joan of Arc, Isabella Romee was in this church.Chapel of Holy Cross. Modern architecture, built in the rock, in Arizona, U.S.A. Finished in 1956. They say that visitors that go into it’s interior feel a strong spiritual energy and a sense of great peace.Basilica of the Sacred Family, in Barcelona, Spain. The construction began in 1882. Antoni Gaudíworked on the project for 40 years. The towers are 170m high.The city of Idar, Germany.The structure was built between 1482 and 1484.Church of Saint Francisco Savior, Bahia, BrazilIt is part of the convent of the FIt in the convent of the Franciscans.It was finished in 1723.Rut is considered to be one of the most extraordinary monuments in the world. It is precious for the exuberant decoration covered with leaves of gold, with carve in jacaranda, fleurons, borders, arches, angels' figures and birds spread in several points, beside panels in Portuguese ceramic tiles, showing scenes of the life of Franciscoranciscans. It was finished in 1723. Rut is considered one of the most extraordinary monuments in the world. It is precious for the exuberant internal decoration covered with leaves of gold, with carve in jacaranda, fleurons, borders, arches, angels' figures and birds spread in several points, besides panels in Portuguese ceramic tiles, showing scenes of the life of S. FranciscoThere are many churches in this presentation. Uncommon in their architecture, in the location, in the grandeur, in their history.。
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a r X i v :a s t r o -p h /0610828v 1 27 O c t 2006Astronomy &Astrophysics manuscript no.(will be inserted by hand later)Chandra and Spitzer observations of CDFS X-ray obscured QSOsI.Georgantopoulos 1A.Georgakakis 2A.Akylas 11Institute of Astronomy &Astrophysics,National Observatory of Athens,Palaia Penteli,15236,Athens,Greece 2Astrophysics Group,Blackett Laboratory,Imperial College,Prince Consort Road,SW72BZ,U.K.Received ;acceptedAbstract.We present Chandra and Spitzer data of the 186,extragalactic,hard 2-10keV X-ray selected sources,which lie in the central part of the Chandra Deep Field South (CDFS).For the vast majority of sources (99.5%)there is a spectroscopic or photometric redshift available.We classify 17sources as X-ray obscured QSOs,according to strictly X-ray criteria,i.e.defined as having large hydrogen column densities (N H >1022cm −2)and luminosities (L x >1044erg s −1).The surface density of X-ray obscured QSOs is ∼210deg −2.We find 18candidate Compton thick N H >1024cm −2sources,of which three have QSO luminosities (L x >1044erg s −1).The X-ray obscured QSO comprise a mixed bag of objects,covering the redshift range z =1.3−4.3.Eight of these show narrow line optical spectra,two show no obscuration in their optical spectra presenting Broad Lines,while for the other seven there is only a photometric redshift available.About half of the X-ray obscured QSOs show high X-ray to optical flux ratios,X/O >1,and red colours,I-3.6µm >bination of the X-ray with the mid-IR 8µm or 24µm flux can be used as an additional diagnostic to sift out the heavily obscured AGN.All X-ray selected QSOs present red mid-IR colours and can be easily separated among mid-IR sources,demonstrating that mid-IR selection provides a powerful tool for the detection of obscured QSOs.Key words.galaxies :active -quasars :general -X-ray :galaxies -X-ray:general1.IntroductionDeep Chandra surveys have resolved a substantial fraction of the X-ray background in the 2-10keV band (Brandt &Hasinger 2005).The vast majority of the detected sources in these fields are AGN,both unobscured (N H <1022cm −2)and obscured (N H >1022cm −2),with the latter dominating at faint fluxes.For example,at the source de-tection limit of the Chandra Deep Field South (CDF-S),f X (2−10keV)∼10−16erg s −1cm −2,about 80%of the sources have N H >1022cm −2(e.g.Alexander et al.2003;Akylas et al.2006).However,there is a clearly a scarcity of NL QSO.Steffen et al.(2003)find that the number of narrow line (NL)AGN decreases at bright luminosities and high red-shift.Only a limited number of X-ray selected NL QSO (L X >1044erg s −1)have been identified at high-z (e.g.Stern et al.2002,Norman et al.2002).These NL QSOs could be rare just because of selec-tion effects (e.g.Treister et al.2004).For example,rest-frame hard X-ray photons at high redshift can penetrate large obscuring columns but the observed optical emis-2I.Georgantopoulos et al.:X-ray Obscured QSOs obscured QSOs(defined here as X-ray luminous,obscuredsources)and to determine their properties.For instance,do X-ray obscured QSOs have high X/O ratios?Can theybe selected through their red(e.g.R-K)colours?Do they all have NL or a fraction presents BL optical spectra(e.g. Akylas et al.2004).Padovani et al.(2004)searched for X-ray obscured QSOs in the CDF-N and CDF-S surveys using a high luminosity and a hardness ratio criterion,finding a few tens candidate X-ray obscured QSOs.However,a num-ber of the X-ray obscured QSO redshifts and luminosities come indirectly from the empirical X/O correlation with X-ray luminosity(Fiore et al.2003,Barger et al.2003). Here,we attempt to study the properties of X-ray ob-scured QSOs in the hard X-ray selected(2-10keV)CDF-S sample.A great advantage of this sample is that for the vast majority of the sources(except one out of247)there is either a spectroscopic or a photometric redshift avail-able.This means that optical selection effects have little impact on our study.Moreover,we determine the X-ray spectral properties of the sources using spectralfittings in-stead of the more crude and indirect method of hardness ratios,minimizing any uncertainties in the determination of the X-ray absorbing column density.Additionally,the wealth of data that has been recently accumulated in the CDFS region as part of the GOODS survey(e.g.Hubble ACS,Spitzer,Very Large Telescope photometry and spec-troscopy)allows us to study in detail the properties of the X-ray obscured QSOs.We use throughout the paper H o=75km s−1Mpc−1,Ωm=0.3,ΩΛ=0.7.2.The Data2.1.X-ray dataThe1Ms CDFS data consist of11individual Chandra(Advanced CCD imaging Spectrometer) ACIS-I pointings with aim points separated by a few arcseconds.The aim point coordinates are α=3h32m28s.0,δ=−27◦48′30′′(J2000).More details are presented in Rosati et al.(2002)and Giacconi et al. (2002).247sources are detected in the2-10keV band down to aflux limit of1×10−16erg cm−2s−1(Γ=1.4). As the roll angles of the individual pointings are different, a fraction of the sources at the edge of thefield-of-view are detected only in a smaller number of pointings.We choose here to analyse only the sources which lie in all 11pointings,in order to maximise the photon statistics. Essentially our source selection is such that the central field-of-view is covered.188sources are detected within all11pointings covering an area of∼0.05deg2.Two sources are associated with stars(Szokoly et al.2004). Only one source has not been optically identified and thus there is no redshift(photometric or spectroscopic) available.We use the PSEXTRACT script in the CIAO v3.2 software package to extract spectra.There are30sources Fig.1.The distribution of the rest-frame column density for all sourceswith more than approximately500counts.The data are grouped so that there are20counts per bin for these sources and thusχ2statistics can apply.For the other sources which have more limited photon statistics we use the C-statistic technique(Cash1979)specifically devel-oped to extract spectral information from data with low signal-to-noise ratio.We use the XSPEC v11.2software package for the spectralfits.Wefit the data using a power-law model absorbed by two cold absorbers:wa*wa*po in XSPEC notation.Thefirst column isfixed to the Galactic (8×1019cm−2)while the second one is the observer’s frame intrinsic column density.Then the rest-frame col-umn density scales as(1+z)2.7(e.g.Barger et al.2003). In the case of the sources with limited photon statistics (<500counts),the power-law photon index has beenfixed toΓ=1.8.The intrinsic luminosities are estimated using a K-correction appropriate for the best value ofΓ.The X-ray spectralfits are presented in table3.The distribution of the rest-frame column density is shown in Fig.1.All candidate Compton thick sources are plotted in the last N H bin.2.2.Optical and mid-IRPart of the CDFS has been observed with the Advanced Camera Surveys(ACS)onboard the Hubble Space Telescope as part of the GOODS survey(Giavalisco et al. 2004).We use here the F775Wfilter data(roughly equiv-alent to the I band).We cross-correlate the X-ray sources with the ACS data using a radius of3arcsec.As the sur-face density of sources increases at faint magnitudes reach-ing∼105deg−20.5mag−1at I=26,Kashikawa et al.2004, one has to be cautious about the possibility of chance co-incidence in the faintest cases(e.g.CDFS-610).For theI.Georgantopoulos et al.:X-ray Obscured QSOs3 sources which do not have I-band photometry available,we quote R magnitudes from Giacconi et al.(2002).Part of the CDFS has been observed by the IR Spitzermission(Werner et al.2004).The Spitzer Infrared ArrayCamera,IRAC,(Fazio et al.2004)8µm and MultibandImaging Photometer,MIPS,(Rieke et al.2004)24µmfluxes are are derived from theflux calibrated,backgroundsubtracted images provided in the Spitzer archive.1Wecross-correlate the Spitzer with the Chandra sources againusing a radius of3arcsec.3.Results3.1.The X-ray obscured QSOs23sources are defined as QSOs based on their high intrin-sic luminosity(L x>1044erg s−1).Of these18(see table1)present high absorbing column densities(N H>1022cm−2)and are thus classified as absorbed QSOs(or X-ray obscured QSOs)purely on the basis of their X-rayspectrum and luminosity.However,at least one source(aBL QSO)is a borderline X-ray obscured QSO as its col-umn density uncertainty is relatively large.Source CDFS-24,which has a BL optical spectrum,is consistent withN H=0cm−2at the90%confidence level.We cautionthat a small error in the measured column density at theobserver’s frame(owing e.g.to a backgroundfluctuation)may translate to an erroneously high column density atthe high redshifts probed here(see Akylas et al.2006).For example,as the rest-frame column density scales as(1+z)2.7,a column as low as∼2.5×1020at the observer’sframe will pass the1022cm−2rest-frame column thresholdat a redshift of z=3.Hereafter,we exclude CDFS-24fromthe X-ray obscured source sample.The resulting samplecontains17sources.Eight of the17X-ray obscured QSOspresent NL optical spectra while two sources are associ-ated with BL AGN.For seven sources there are no spectraavailable.The redshift distribution is given in Fig.2.Allsources apart from one lie at redshift z>2.We estimate the surface density of X-ray obscuredQSOs by taking into account the area covered by thesurvey at a givenflux.We estimate a surface densityof210deg−2down to aflux of f2−10≈1.6×10−15erg cm−2s−1.Five more luminous(L x>1044erg s−1)sources present no absorption(N H>1022cm−2)and arethus classified here as X-ray unobscured QSOs(see table2).The surface density of X-ray unobscured QSOs is∼60deg−2at aflux of f2−10∼5×10−15erg cm−2s−1.The ra-tio of X-ray obscured to unobscured QSOs is R=3.4±1.7.However,at the sameflux limit,∼5×10−15erg cm−2s−1,we estimate R∼1.Four of the X-ray unobscured QSOsare associated with BL AGN,while for the other one thereis no spectrum available.4I.Georgantopoulos et al.:X-ray Obscured QSOs statistics revealing no evidence for an Fe line.The90%upper limits on the equivalent width of the6.4keV lineare as high as several keV in all three cases.In total wefind8Compton thick AGN when we con-sider all X-ray luminosities.These Compton thick AGNare revealed directly through the detection of their absorp-tion turnover.Such column densities cannot be detectedat low redshift in the Chandra energy passband as the ab-sorption turnover occurs at energies>10keV.At highredshift the k-correction shifts the absorption turnover atlow energies.It is likely that these8AGN represent onlya fraction of the Compton thick sources in our sample.Indeed,at lower redshifts or higher column densities thecolumn density cannot be directly detected.Instead,thespectrum will appearflat.We have thus looked for caseswhere leaving the spectral index free,results in a veryflatspectrum:Γ∼1orflatter with∆C=2.7.Wefind ten such cases,raising the totalnumber of candidate Compton thick sources to18(see table3).3.3.X/O ratio and optical-IR colourThe optical(I or R)magnitudes and X-ray to opticalflux ratios,X/O,are presented in table1.Four X-ray obscured QSOs fall outside the ACS survey.For these we present R magnitudes instead from VLT/FORS.For CDFS-72there is only a magnitude lower limit as this was not detected at the limit of the FORS observations(R=26).The X/O is defined as the ratio of the2-10keVflux to optical(I band)flux:X/O=log(f x/f o)=5.7+logf x+I/2.5(1) In the case where we have only R magnitudes avail-able the X/O ratio is estimated using the equation in Hornschemeier et al.(2003).Three sources(CDFS-6,72, 76)have not been covered by the Spitzer IRAC survey. Five sources have not been covered by MIPS(CDFS-6, 72,76,61,54).All X-ray obscured QSOs which lie within the IRACfield-of-view have been detected at8µm.Instead only seven have been detected by MIPS at24µm.Finally, the I-3.6µm colour is given in Table1.The3.6µm mag-nitude is estimated from the relation:m3.6µm=−2.5logf3.6µm+23.9(2) where theflux f3.6is in units ofµJy.The X/O ratio as a function of the I-3.6µm colour is given in Fig.3.There is a strong correlation between the X/O and the I-3.6µm colour in the sense that the redder sources present high X/O.All the high X/O sources(X/O>1or Extreme X/O sources EXO)have I-3.6µm>4.This colour is roughly equivalent to an Extremely Red Object(ERO)defined as having R−K>5.However,not all X-ray obscured QSOs are EXOs or EROs.Reversely,one of the X-ray unobscured QSOs is an EXO(CDFS-67).Fig.3.The logarithm of the X-ray to opticalflux ratio or X/O as a function of the I−3.6µm colour.X-ray obscured and unobscured QSOs are denoted withfilled circles and crosses respectively.The open circle denotes the border-line X-ray obscured QSO CDFS-24.Thefilled triangles represent the Compton thick AGN with luminosity L x< 1044erg s−1.The remaining sources are shown as dots.3.4.Mid-IR propertiesAdditional clues on the nature of the X-ray obscured QSOs can be provided by their mid-IR properties.The X-ray to mid-IRflux ratios provide a useful diagnostic for identifying obscured AGN.Unobscured AGN have ratios around unity(e.g.Lutz et al.2004).In Fig.4we present the absorbed X-rayflux against the IRAC8µm(left panel) and24µm(right panel)flux density for all X-ray sources. The solid lines(adapted from Alonso-Herrero et al.2004) denote the region which is occupied by the hard X-ray selected AGN in the HEAO-1sample of Piccinotti et al. (1982).There are four X-ray obscured QSOs which lie be-low the AGN locus of points in the24µm diagram.The same X-ray obscured QSOs have low X-rayfluxes rela-tive to their8µmflux densities.These are associated with a BL QSO(CDFS-62),and three NL QSOs(CDFS-202, CDFS-45,CDFS-31).These have less X-ray emission for their mid-IRflux density and thus they should be associ-ated with the most heavily absorbed sources.Surprisingly, none of the candidate Compton thick sources are among these.The BL QSO CDFS-62presents no evidence of red-dening in the optical having I−3.6≈1.In contrast, sources CDFS-45and CDFS-31have I−3.6>4be-ing among the redder sources in our sample.CDFS-202 presents little reddening with I−3.6=2.8.Norman et al. (2002)present in detail the properties of this NL QSO at a redshift of3.7.In the mid-IR,AGN present red,featureless spectra (Hao et al.2005).Thus the mid-IR colours can provide aI.Georgantopoulos et al.:X-ray Obscured QSOs5Fig.4.The 2-10keV absorbed X-ray flux versus the Spitzer IRAC 8µm (left panel)and MIPS 24µm monochromatic flux for hard X-ray selected sources in the CDFS.Symbols as in Fig.3;open triangles denote 24µm luminosity upper limits.The solid lines in the right panel denote the region occupied by the Piccinotti AGN sample (see Alonso-Herrero et al.2004).powerful tool to identify AGN (Lacy et al.2004,Stern et al.2004,Hatziminaoglou et al.2005).In Fig.5we plot the mid-IR colours of our sample.The solid lines denote the “red”region empirically defined by Lacy et al.(2004)to contain luminous cy et al.find that the normal galaxies lie in the blue part of the diagram having colours clustering around [8.0]-[4.5]=-0.5and [5.8]-[3.6]=-0.5.The vast majority of our X-ray selected of QSOs are “red”.The only source lying outside (albeit only marginally)the red AGN region defined by Lacy et al.is CDFS-600.4.DiscussionWe have derived the X-ray spectral properties for all 186hard extragalactic (2-10keV)X-ray selected sources within the central field-of-view of the CDF-S.We define X-ray obscured QSOs,strictly using X-ray criteria and regardless of their optical spectrum,as those having high unobscured luminosities L x >1044erg s −1and high ob-scuration column density N H >1022cm −2.We find 17X-ray obscured QSOs among the 186sources.The ratio of X-ray unobscured to X-ray obscured QSOs (L x >1044erg s −1)is 3.4±1.7.This consistent with the ratio at lower luminosities (L x <1044erg s −1)which is R ≈2.5±0.5.At first this comes at odds with recent findings which show that the fraction of obscured AGN decreases significantly at high luminosities:Ueda et al.(2003),La Franca et al.(2005),Akylas et al.(2006)find ratios,R,well below unity,at high luminosities.This apparent discrepancy could be attributed to the fact that we are using a pencil beam flux limited survey and thus we cannot probe large enough volumes to detect a high number of luminous unobscuredFig.5.Spitzer IRAC colours.We denote with solid lines the region which is used as an AGN diagnostic tool in mid-IR according to Lacy et al.Symbols as in Fig.3.QSOs (see also the discussion by La Franca et al.2005and Akylas et al.2006).The optical spectra of the X-ray obscured QSOs show that these comprise a mixed bag of objects.Eight sources present NL spectra,two are associated with BL AGN while for seven more there are no spectra available.The BL source CDFS-062presents a high column,2×1023cm −2.This column should correspond to A V ∼100us-6I.Georgantopoulos et al.:X-ray Obscured QSOsFig.6.Power-lawfits andχ2residuals to the spectra of the X-ray obscured QSOsI.Georgantopoulos et al.:X-ray Obscured QSOs7 Table1.The X-ray obscured QSOs6J033302.7-2748234.0+1.6−1.92.4625.67a 4.17a44.23---14.40 1.36-24†J033242.0-2752034.0+4.6−4.03.61022.40 1.4544.4222.7124.3-14.590.07BL27J033239.8-27485147.8+8.6−7.83.06424.71 3.8644.5029.4166.6-14.37 1.21NL31J033237.9-2752132.1+0.5−0.61.60324.11 4.5944.17259.11085.4-14.06 1.28NL45J033225.8-27430612.2+3.3−2.82.29125.37 4.5644.08158.5535.7-14.49 1.36NL54J033214.7-27542218.8+6.1−5.52.56125.69a-44.08 5.3--14.600.87NL57J033213.0-27523818.8+5.2−4.62.56224.17 2.4844.1510.9<40-14.530.84NL61J033210.6-2743092.4+0.7−0.92.0224.51 5.0044.2890.3--14.08 1.42-62J033209.5-27480723.2+4.5−4.22.81020.49 1.0544.39244.920.2-14.38-0.48BL68J033201.6-2743276.9+3.0−3.02.72623.99 2.1144.2714.9<40-14.350.94BL72J033158.3-27504310.4+3.1−2.21.99>26a-44.09---14.33>1.56-76J033152.6-27501819.8+3.8−3.62.39424.50a 4.64a44.34---14.280.72NL159J033250.4-2752539.5+6.7−3.83.3024.86 3.9744.6530.6190.5-14.28 1.35-202J033229.9-27510636.8+20.5−15.73.70024.54 2.8244.12 1.093.1-14.920.59NL227J033205.4-27464465.4+22.0−16.52.1826.90 5.8044.0025.3<40-14.58 1.87-600∗J033213.9-274526380+180−1801.3323.25 3.7144.4327.451.2-14.580.41NL605∗J033239.2-2748332700+3800−17004.2926.27 4.1144.95 5.4<40-14.92 1.27-610∗J033219.9-275159520+580−2802.0427.90 6.4144.1821.4<40-15.01 1.85-8I.Georgantopoulos et al.:X-ray Obscured QSOsTable2.X-ray unobscured QSOs11J033260.0-274748<0.2 2.57921.83a 2.73a44.54---14.150.08BL 22J033243.3-274915<0.2 1.92022.54 1.9744.1632.4152.7-14.300.41BL 42J033227.1-274105<0.020.7319.11 1.7044.25661.5999.7-13.200.14-60J033211.0-274415<0.10 1.61522.37 2.5344.2293.9285.7-14.050.59BL 67J033202.5-274601<0.43 1.61623.73 3.8444.0649.4258.0-14.16 1.03BLI.Georgantopoulos et al.:X-ray Obscured QSOs9these14sources.Interestingly,the Compton thick samples of Tozzi et al.and ours have little overlap:only sources CDFS-153,505,531and610are common.However,Tozzi et al.do not include in their Compton thick sample the sources which present column densities N H>1024cm−2, i.e.CDFS-599,600,601,605,609,634.This would al-leviate the discrepancy between the two samples.Finally, there are sources in their sample presenting veryflat spec-tral index,e.g.CDFS-25withΓ=0.29+0.21−0.20,which should be considered as candidate Compton thick sources.5.ConclusionsWe have explored the X-ray optical and mid-IR properties of X-ray obscured QSOs on the CDFS.We classify X-ray obscured QSOs on the basis of purely X-ray criteria i.e. high luminosity L x>1044erg s−1combined with high hy-drogen column density N H>1022cm−2.We are selecting X-ray obscured through the186hard extragalactic X-ray sources which lie in the central FOV of the CDFS.We have derived proper X-ray spectra(instead of hardness ratios)for all our sources.Photometric or spectroscopic redshifts exist for the vast majority of the sources(185 out of186)ascertaining that optical selection biases are of no importance in our study.Wefind17X-ray obscured QSOs spanning the redshift range1.3-4.2.Our main re-sults can be summarised as follows:1.The surface density of X-ray obscured QSOs is210 deg−2at f2−10∼10−15erg cm−2s−1.2.Our X-ray obscured QSO sample comprises of sources with both NL and BL spectra.The BL source with the highest absorption(1023cm−2)is a mini-BAL.3.Three out of17X-ray obscured QSOs present very high column densities(>1024cm−2)and are classified as Compton thick QSOs.When we consider all luminosities, we classify18sources as candidate Compton thick AGN, based on the detection of either high column densities or flat X-ray spectra.4.About half of our X-ray obscured QSOs presenta very high X-ray to opticalflux ratio,X/O>1.These present very red colours(I-3.6µm)and most can be clas-sified as EROs.5.The X-ray to mid-IRflux ratio can provide a com-plementary tool to select heavily obscured sources.Four out of17X-ray obscured QSOs appear to have a low X-ray to mid-IRflux ratio;only two of these four sources have either a red colour or a high X/O ratio.6.Practically all17QSOs have red mid-IR colours and can be very easily separated from the normal galaxies 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1.800.86+0.32−0.2941.52Galaxy0.220.21-4J033303.7-2745191.93+0.20−0.15<0.4343.50- 1.2600.340.906J033302.7-2748232.25+0.28−0.194.02+1.61−1.8844.23- 2.460.390.6310J033259.9-274627 1.80 2.71+0.53−0.4842.55LEX0.4240.51-11J033260.0-2747481.97+0.11−0.09<0.5944.54BLAGN 2.5790.71 1.1612J033259.8-2750312.20+0.21−0.18<0.0741.69ABS0.2510.22 1.0015J033253.0-2751201.91+0.08−0.220.42+0.50−0.4243.51BLAGN 1.230.37 1.1117J033249.3-275505 1.800.42+0.68−0.4242.62-0.870.11-18J033248.0-2742331.98+0.09−0.102.44+0.49−0.3743.92LEX0.979 1.660.8120J033244.5-274941 1.80 6.51+1.68−1.4843.20- 1.0160.28-21J033244.4-275252 1.80<2.6443.81BLAGN 3.4710.07-22J033243.3-2749151.92+0.16−0.12<0.6844.16BLAGN 1.920.500.77 23J033242.0-274400 1.80<0.2142.80-0.730.25-24J033242.0-275203 1.80 4.02+4.59−4.0244.42BLAGN 3.6100.26-25∗J033240.9-2755480.57+0.39−0.370.38−0.30+0.3042.88ABS0.6250.43-26J033239.8-274612 1.80 4.63+1.98−1.7243.56- 1.650.21-27J033239.8-274851 1.8047.95+8.61−7.7944.50HEX 3.0640.44-28J033239.2-274602 1.80 1.24+0.99−0.8343.16BLAGN 1.2160.17-29J033239.0-2757012.02+0.16−0.194.47+0.92−0.8242.69-0.30 1.54 1.1831J033237.9-2752132.22+0.11−0.142.14+0.50−0.6344.17HEX 1.6030.870.8333J033236.8-2744071.75+0.11−0.160.12+0.16−0.1243.11LEX0.670.640.9334J033235.0-275512 1.800.86+0.40−0.4043.00-0.8390.29-36J033233.1-274548 1.800.38+0.21−0.1741.90-0.330.20-37J033232.2-274156 1.800.54+0.89−0.5442.72-0.960.11-38J033230.3-2745052.13+0.12−0.11<0.1743.13BLAGN0.740.52 1.2739J033230.1-2745301.87+0.08−0.08<0.3343.91BLAGN 1.220.95 1.1941J033227.7-274145 1.807.78+1.32−1.2143.11HEX0.6670.63-42J033227.1-2741052.09+0.03−0.030.1744.25-0.73 6.31 1.2543J033226.9-274146 1.80 2.91+0.81−0.7342.84LEX0.7370.27-44J033226.6-2740362.44+0.09−0.08<0.2643.59- 1.0310.68 1.1245J033225.8-274306 1.8012.21+3.29−2.8244.08LEX 2.2910.33-46J033225.3-2742192.23+0.29−0.290.77+0.90−0.7743.59BLAGN 1.6170.23 1.3447J033225.1-274101 1.807.22+1.84−1.8042.86LEX0.7330.28-48J033224.9-275601 1.80 5.55+1.48−1.3043.43- 1.260.30-49J033224.3-274127 1.80<0.1542.49LEX0.5340.26-50∗J033219.1-2747561.01+0.53−0.470.13+0.32−0.1342.45ABS0.670.14-51J033217.3-2752212.69+0.28−0.4430.14+5.07−8.2143.76- 1.0970.87 1.2752J033217.2-2743042.03+0.16−0.12<0.1342.80BLAGN0.5690.450.80 53J033215.1-275128 1.80<0.0842.69BLAGN0.6750.24-54J033214.7-275422 1.8018.80+6.08−5.5044.08HEX 2.5610.25-55J033214.1-275101 1.80 1.86+0.32−0.3041.37HEX0.1220.51-56J033213.3-2742411.49+0.19−0.152.05+0.73−0.4543.25-0.605 1.120.9357J033213.0-275238 1.8018.80+5.21−4.6344.15HEX 2.5620.29-58J033211.8-274629 1.80 2.76+1.01−0.9042.94-0.920.20-59J033211.5-2752141.74+0.18−0.181.81+0.84−0.6043.36-0.970.460.6860J033211.0-2744151.92+0.12−0.09<0.5144.22BLAGN 1.6150.89 1.1961J033210.6-2743092.02+0.10−0.122.43+0.75−0.9444.28- 2.020.830.9062J033209.5-274807 1.8023.20+4.50−4.1644.39BLAGN 2.8100.42-63J033208.7-2747351.93+0.03−0.03<0.0443.82BLAGN0.544 5.21 1.3364J033208.1-2746581.59+0.17−0.170.21+0.18−0.1141.37-0.130.46 1.4465J033204.0-275330 1.800.50+0.57−0.5043.10- 1.100.19-66J033203.7-274604 1.808.99+1.26−1.1643.22LEX0.574 1.17-。