Double Genitive
双重所有格（double
双重所有格（double genitive）所谓“双重所有格（double genitive）”，是指名词所有格或名词性物主代词同of构成的所有格，即“of＋名词所有格”。
双重所有格有以下⼏个特征：1） “of＋名词所有格”中的名词必须表⽰⼈，不能表⽰事物。
因此，我们可以说：a play of Shakespeare’s（莎⼠⽐亚的⼀个戏剧）， a friend of my wife’s（我妻⼦的⼀个朋友），但却不能说a funnel of the ship’s或 a leg of a table’s，⽽且该名词必须是特指的，不能是泛指的。
⽐如我们可以说，a friend of the doctor’s（这位医⽣的⼀个朋友），a novel of the writer’s（那位作者的⼀部⼩说），⽽不能说a friend of a doctor’s或 a novel of a writer’s。
2）除了修饰的原因外，⽤双重所有格主要是由于被修饰词有排他性的限定词（determiner），如冠词、某些不定代词、指⽰代词、疑问代词、数词等。
⽐如我们不能说 an our old acquaintance，⽽必须说an old acquaintance of ours（我们的⼀个⽼相识）；不能说many their books，正确的说法是 many book of theirs（他们的许多书）。
再如：This demand oftheirs is quite ridiculous．他们的这个要求⾮常可笑。
“This foolish wife of mine thinks I’m a great artist，” said he．“我那愚蠢的⽼婆以为我是个⼤艺术家，”他说道。
3）注意区别下列四种表达⽅式含义的差别：one of my brother’s friends（明确表⽰我兄弟有⼀个以上的朋友）a friend of my brother’s（暗⽰我兄弟有⼀个以上的朋友）a friend of my brother（对我兄弟有好感的⼈）my brother’s friend（我兄弟唯⼀的⼀个朋友或刚谈及的那⼀个朋友）。
芝加哥论文格式范例
芝加哥论文格式范例篇一：论文格式Chicago该格式由芝加哥大学出版社( University of Chicago Press) 制定, 可用于人文科学类和自然科学类论文, 其基本格式为: 正文中按引用先后顺序连续编排序号, 在该页底以脚注( Footnotes ) 或在文末以尾注( Endnotes ) 形式注明出处, 或在文末单列参考文献项, 以Bibliography 为标题。
芝加哥引注格式在美国比在英国的应用更多，标准是《芝加哥引注格式使用指南》（The Chicago Manual of Style），但是也有很多用户把凯特?杜拉宾（Kate Turabian）为学生编写的《学期、学位、学术论文写作指南》（A Manual for Writers of Term Papers, Theses and Dissertations）作为参考。
所以，芝加哥引注格式也称为杜拉宾引注格式。
芝加哥引注格式主要用脚注形式引注，但是也可以用作者姓名的文中引注格式。
文中引注与姓名日期名字日期（哈佛）格式和APA格式一样，芝加哥格式可以在文本中做引注，在括号中写出作者或组织者的姓氏全程或缩写，加上年份，如果需要的话，还可以加上页码，比如: (Goman 1989, 59) ，或者 (Fairbairn and Fairbairn 2001) ，或者 (MHRA 2004).如果一个文献有一到三个作者，在引注中依次写出他们的姓氏。
如果有4个或者多于4个作者，写出第一个作者的名字然后写‘et al.’代替其他作者的名字，比如：(Brown et al. 2009). 文后参考文献在论文最后制作一个标题为“参考文献”的书单，把所有的文献条目按照字母表顺序排列。
这样，上面说到的三个文献例子，按照顺序可以排列为：? Fairbairn, Gavin and Susan Fairbairn. 2001. Reading at university: A guide for students. Maidenhead: Open University Press.文后参考文献的格式要求：?使用作者的全名。
高考英语阅读理解复习-科技类20篇(含解析)
科技类词汇对应阅读passage1A snake﹣robot designer，a technologist，an extradimensional physicist and a journalist walk into a room.The journalist turns to the crowd and asks：Should we build houses on the ocean？Like a think﹣tank panel，members of the team dream up far﹣out answers to the crucial problem，such as self﹣driving housing units that could park on top of one another in the coastal city center.The setting is X，the enterprise which considers more than100ideas each year，in areas ranging from clean energy to artificial intelligence.Although only a tiny percentage become"projects"with far﹣reaching creativity，these projects exist，ultimately，to change the world，like Waymo，the biggest self﹣driving﹣car company.In the past60years，something strange has happened.As the academic study of creativity has thrived （蓬勃发展），the label innovation may have covered every tiny change of a soda can or a toothpaste flavor，but the rate of productivity growth has been mostly declining since the1970s.John Fernald，an economist，points out that the notable exception to the post﹣1970decline in productivity occurred when businesses throughout the economy finally figured out the breakthrough technology﹣information technology.John Fernald says，"It's possible that productivity took off，because we picked all the low﹣hanging fruit from the IT wave."Actually，the world economy continues to harvest the benefits of IT.But where will the next technology shock come from？Breakthrough technology results from two distinct activities﹣invention and innovation.Invention is typically the work of scientists and researchers in labs，while innovation is an invention put to commercial use.Seldom do the two activities occur successfully under the same roof.They tend to thrive in opposite conditions；while competition and consumer choice encourage innovation，invention has historically progressed in labs that are protected from the pressure to generate profit.Allowing well﹣funded and diverse teams to try to solve big problems is what gave us the computer and the Internet.Today，we fail to give attention to planting the seeds of this kind of ambitious research，while complaining about the harvest."Companies are really good at combining existing breakthroughs in ways that consumers like.But the breakthroughs come from patient and curious scientists，not the rush to market，"says Jon Gertner，the author of The Idea Factory."Technology is a tall tree，"John Fernald said."But planting the seeds of invention and harvesting the fruit of innovation are entirely distinct skills，often mastered by different organizations and separated by manyyears."As for me，both of them are essential for technology，although they are relatively independent.I don't think X is a planter or a harvester，actually.It is like building taller ladders.Nobody knows for sure what，if anything，the employees at such enterprises are going to find up on those ladders.But they're reaching.At least someone is.（1）What is the main purpose of the first two paragraphs？A．To present the process of group discussion.B．To illustrate X's worry about big problems.C．To reveal the importance of the crazy ideas.D．To stress the varied backgrounds of the team.（2）What can we learn from the passage？A．Breakthroughs must stand the test of the market.B．Innovation on necessities can promote productivity.C．Invention develops slowly under the pressure of profit.D．The harvest of innovation lies in some ambitious research.（3）Regarding John Fernald's view on technology，the author is.A．supportiveB．cautiousC．uncertainD．critical（4）What can be inferred about X from the passage？A．It will focus on innovation.B．It will have its outcome soon.C．It may give in to its fruitless reality.D．It may bring an encouraging outlook.【分析】这是一篇说明文。
2009年分子生物学quiz1参考答案(精)
2009年分子生物学quizl 参考答案2. What is central dogma? What contents have you learned in each part of the central dogma? (5’)The central dogma is the pathway for the flow of genetic information.We have learnt the maintenance of the genome (the structure of the genetic material and its faithful duplication) and the expression of the genome (the conversion of genetic instructions contained in DNA into proteins).(缺 reverse transcription 扣一分)3. Write out the structure of four bases, label the positions that participate Watson-Crick base pairing and that connect to the ribose? (10’)如果解答中可以 置等，会酌情wg/Q sugar4. What are the features of DNA structure? And how RNA structure differs from DNA? (2 Copyright © 2004 Pearson Education f I nc., publishing as Benjamin Cummings Two antiparallel polynucleotide chains are twisting around each other in the form of a double helix. 6’(polynucleotide(building block) 2’,antiparallel 2’,double helix 2’)Hydrogen Bonding determines the Specificity of base pairing (complimentarity).2’Stacking interaction between bases determines the stability of DNA double helix, hydrogen bond also contributes to stability.2’The double helix has Minor and Major grooves. (A B Z forms)2’Differences ：Primary structure( building block): 2’dNTP vs. rNTP ; T vs. U ; double-stranded vs. single-stranded.Secondary structure: 4’键；AG 是二环，TC 是单环；氢键的位 The features of DNA structure ：间是双键，CGDNA has stable double helical structure. (full complimentarity)RNA chains fold back on themselves to form local regions of double helix similar to A-form DNA. RNA helix are the base-paired segments between short stretches of complementary sequences, which adopt one of the various stem-loop structures, pseudoknots.( inter- and intra-molecular base pairing) Tertiary structures: 2’DNA: no tertiary structure.RNA can fold up into complex tertiary structures, because RNA has enormous rotational freedom in the backbone of its non-base-paired regions.pare the chemistry of DNA synthesis and RNA synthesis. (5’)(clues: compare=differences+the same; chemistry=substrate+direction+ energy)Differences:(1)DNA synthesis requires deoxynucleotide triphosphates while RNA synthesis requires oxynucleotide triphosphates;(1')(2)The base for DNA synthesis are A/T/C/G while that for RNA synthesis are A/U/C/G;(1')(3)DNA synthesis needs a primer:template junction while RNA synthesis do not;(1')The same:(1)The direction of both DNA synthesis and RNA synthesis is 5' to 3';(1')(2)The energy needed for DNA synthesis as well as RNA synthesis is hydrolysis of pyrophosphate (PPi).(1')6.Describe the functions of each domain of the DNA polymerase. (14’+1')DNA polymerase palm domain(1'):(1)Contains two catalytic sites, one for addition of dNTPs (1')and one for removal of the mispaired dNTP.(1')(2)The polymerization site: (1) binds to two metal ions that alter the chemical environment around the catalytic site and lead to the catalysis. (1')(2) Monitors the accuracy of base-pairing for the most recently added nucleotides by forming extensive hydrogen bond contacts with minor groove of the newly synthesized DNA. (1')(3)Exonuclease site/proof reading site . The mechanism of proof reading is kinetic selectivity(1') and the mismatched dNMP is removed by proofreading exonuclease in the direction of 3'-5'(1'). DNA polymerase finger domain:(1')(1)Binds to the incoming dNTP, encloses the correct paired dNTP to the position for catalysis;(1') (2)Bends the template to expose the only nucleotide at the template that ready for forming base pair with the incoming nucleotide;(1')(3)Stabilization of the pyrophosphate;(1')DNA polymerase thumb domain:(1')(1)Not directly involved in catalysis;(2)Interacts with the synthesized DNA to maintain correct position of the primer and the active site, (1')and to maintain a strong association between DNA Pol and its substrate.(1')7.How replication of a DNA molecule is accomplished in bacteria ?Initiation:(1)Recognition and binding of OriC by DnaA(initiator)-ATP.(2)Helicase (DnaB) loading and DnaC(helicase loader) and DNA unwinding.(3)Primase synthesizes RNA primer, and D NA Polymerase III synthesizes the new DNA strand.(The "trombone" model was developed to explain lagging strand and Elongation:leading strand synthesized simultaneously):(1)Leading strand: newly synthesized DNA strand that is continuously copied from the template strand by a DNA polymerase after the first RNA primer was made by a primase. A sliding clamp is usually loaded to the DNA polymerase to increase the polymerase processivity. The3 direction of theing strand is the same as the moving direction of the replication fork.(2)Lagging strand is discontinuously copied from the template strand. The 3 direction of the lagging strand is opposite to the moving direction of the replication fork. Primase makes RNA primers periodically after the template strand is unwound and becomes single-stranded. DNA polymerase extends each primer to synthesis short DNA fragments, called Okazaki fragments. The polymerase dissociates from the template strand when it meets the previous Okazaki fragment. Finally, RNA primers are digested by an RNase H activity, and the gaps are filled by DNA polymerase. At last, the adjacent Okazaki fragments are covalently joined together by a DNA ligase to generate a continuous, intact strand of new DNA.Termination:Type II topoisomerases separate daughter DNA molecules.8.How transcription of a RNA molecule by RNA polymerase II is initiated, elongated and terminated in eukaryotes (25’)Initiation: (11’+附加分)A.1.Promoter recognition: TBP in TFIID binds to the TATA box；(1’) TFIIA and TFIIB are recruited withTFIIB binding to the BRE；(1’)2. RNA Pol II recruitment: RNA Pol II-TFIIF complex is the recruited；(1’)3.TFIIE and TFIIH then bind upstream of Pol II (to form the pre-initiation complex).(1 ()如果提到了pre-initiation complex,有1 分的附加分)B.Promoter melting using energy from ATP hydrolysis by TFIIH .(2’)C.Promoter escapes after the phosphorylation of the CTD tail. (2’)Additional proteins are needed for transcription initiation in vivo:■The mediator complex (1 )■Transcriptional regulatory proteins (1 )■Nucleosome-modifying enzymes (1’)Tips:1、题目已经问了是真核中的情况，所以必须把相关的真核里的factor都回答出来，不然没分；2、B和C两点非常重要，分值也很大，由此可见把握keypoints的重要性；3、很少同学可以回答出in vivo状态下所需要的3种蛋白；4、如果可以答出另外一些细节，比如“TBP binds to and distorts DNA using a p sheet inserted into the minor groove”，会有少量加分。
Lecture 5. Genitive Noun
this brilliant idea of David’s which novel of Dickens’
two novels of Dickens’
Assignment
Review the relevant part in our text book.
e.g.
Mary’s and Bob’s books
如果仅在第二个名词之后加-’s，则指两人共有的书。
Mary and Bob’s books
1. Formation of genitive nouns
名词属格的构成
e). “ 名词词组 + 同位语”构成属格时， -’s 加
在同位语名词之后，也可以前后都加。
双重属格所修饰的名词可带 a, any, some 等 表示非确定特指的限定词，但通常不带定冠 词。 e.g. Some/ any daughters of Mrs. Green’s
5. Double genitive
双重属格
双重属格所修饰的名词也可和 this, that 等 指示限定词连用，表示爱憎褒贬等感情色彩。 还可以带有which等疑问限定词和数词等定量 限定词。
名词属格的用法
c). 名词属格和 of-词组： 名词属格和of-词组意
义和用法上有许多相通之处，有时可以互换： e.g. China’s foreign policy = the foreign policy of China the prime minister’s arrival = the arrival of the prime minister the elephant’s trunk = the trunk of the elephant
常用数学符号大全
常用数学符号大全1、几何符号⊥∥∠⌒⊙≡≌△2、代数符号∝∧∨～∫≠≤≥≈∞∶3、运算符号如加号（＋），减号（－），乘号（×或·），除号（÷或／），两个集合的并集（∪），交集（∩），根号（√），对数（log，lg，ln），比（：），微分（dx），积分（∫），曲线积分（∮）等。
4、集合符号∪∩∈5、特殊符号∑π（圆周率）6、推理符号|a| ⊥∽△∠∩∪≠≡±≥≤∈←↑→↓↖↗↘↙∥∧∨&; §①②③④⑤⑥⑦⑧⑨⑩ΓΔΘΛΞΟΠΣΦΧΨΩαβγδεζηθικλμνξοπρστυφχψωⅠ Ⅱ Ⅲ Ⅳ Ⅴ Ⅵ Ⅶ Ⅷ Ⅸ Ⅹ Ⅺ Ⅻⅰ ⅱ ⅲ ⅳ ⅴ ⅵ ⅶ ⅷ ⅸ ⅹ∈∏∑∕√∝∞∟ ∠∣∥∧∨∩∪∫∮∴∵∶∷∽≈≌≒≠≡≤≥≦≧≮≯⊕⊙⊥⊿⌒℃指数0123：o1237、数量符号如：i，2+i，a，x，自然对数底e，圆周率π。
8、关系符号如“＝”是等号，“≈”是近似符号，“≠”是不等号，“＞”是大于符号，“＜”是小于符号，“≥”是大于或等于符号（也可写作“≮”），“≤”是小于或等于符号（也可写作“≯”），。
“→ ”表示变量变化的趋势，“∽”是相似符号，“≌”是全等号，“∥”是平行符号，“⊥”是垂直符号，“∝”是成正比符号，（没有成反比符号，但可以用成正比符号配倒数当作成反比）“∈”是属于符号，“??”是“包含”符号等。
9、结合符号如小括号“（）”中括号“［］”，大括号“｛｝”横线“—”10、性质符号如正号“＋”，负号“－”，绝对值符号“| |”正负号“±”11、省略符号如三角形（△），直角三角形（Rt△），正弦（sin），余弦（cos），x的函数（f(x)），极限（lim），角（∠），∵因为，（一个脚站着的，站不住）∴所以，（两个脚站着的，能站住）总和（∑），连乘（∏），从n个元素中每次取出r个元素所有不同的组合数（C(r)(n) ），幂（A，Ac，Aq，x^n）等。
Double_genitive_双重属格
3．of 后的名词属格，在有上下文的情况下， 可以用名词性物主代词代替，如： some books of Charles Dickens’s -some books of his two cups of Lily’s -- two cups of hers 4．双重属格所修饰的名词可以为疑问代词 所修饰，如： Which novel of Ernest Hemingway do you like best of all? How many songs of Jackie Chan have you learned so far?
4. always否定式： e.g.： He is not always so sad. 5. all the time 否定式： e.g.： A foolish man doesn't make a mistake all the time. 6. entirely, altogether, completely, quite 否定 式：“不完全……”，“并非完全……” e.g.： He felt not altogether satisfied. I don\‘t agree completely. What he did was not quite proper.
但是在运用时，双重属格有八点要注意： 1．双重属格的of 属格只能用指人的名词， 而且这个名词必须是确定的对象，即特指， 如： a novel of Lu Xun’s this cute boy of Mr Lee’s those broken shoes of Carl’s 2．被双重属格修饰的名词只能为非特指的 名词，下例就错了： the play of Bernard Shaw’s * the cotton field of Mr. Brown’s *
倍数增加的表示法及译法
倍数增加的表示法及译法一、表示法:汉语表示“增加了几倍”时，英语的倍数表示倍数需减一，译成“增加了n-1倍”以表示净增加数。
如果译成“增加到n倍”或“为原来的n倍”，则照译不误。
1.句式特点：表示增加意义的动词＋n times“表示成倍地增长，译成”增加到N倍“或”增加n-1倍。
注：1倍 once; 2倍twice（或double）；3倍thrice（或three times）2.句式特点：表示增加意义的动词＋ｂｙ＋ n times，该句式与上述相同。
3.句式特点：表示增加意义的动词＋to＋ n times表示增加到N倍，译成”增加了n-1倍。
4.句式特点：表示增加意义的动词＋by a factor of ＋ n times5.句式特点：表示增加意义的动词＋比较级＋by a factor of ＋ n times表示增加以后达到的倍数，译成”比。
大（长、宽。
）N-1倍。
6.句式特点：表示增加意义的动词＋ n times＋比较级＋than......7.句式特点：表示增加意义的动词＋ n times +adj./adv. +as....8.句式特点：表示增加意义的动词＋a ＋ n times(或n-fold) ＋increase.......表示增加到N倍，译成”增加了N－1倍。
9.句式特点：表示增加意义的动词＋as + adj./adv.+ again as.....译成”比。
大（长、宽。
倍）例子： Line A is as long again as line B. A线比B 线长1倍。
This machine turns half as fast again as that one.这台机器转动比那台机器快半倍。
10.句式特点：表示增加意义的动词＋half as + adj./adv.+ again as.....译成”比。
大（长、宽。
半倍）。
11. 句式特点：用double表示倍数，译成”等于.....的2倍“或”增加了1倍。
3-夹注与引用文献格式(APA格式)
In-text CitationsAPA StyleAPA style is usually applied to Education, Business, Social Sciences and related fields. The documentation in APA style consists of:⏹p arenthetical references (author‟s last name, date, page number)⏹References⏹*optional footnotes with endnotes pageAPA in-text citationsAPA citations are widely used in the fields of psychology, education, engineering, business, and the social sciences. They are in-text. Footnotes or endnotes are used only for analysis and commentary, not for citations. APA emphasizes the year of publication, which comes immediately after the author‟s name.⏹APA in-text citations involve enclosing the author‟s surname and the date of publicationwithin parentheses, separated by a comma, generally placed immediately after the reference or at the end of the sentence in which the reference is made. For example:Propositions are unstructured, albeit fine-grained entities (Schiffer, 2003).⏹If the author‟s surname is mentioned in the sentence, only the year is inserted in parentheses.For example:John MacFarlane (2003) has argued that believers in a metaphysically open future should accept that the truth of an utterance is relative to a context of evolution.⏹If there are two authors, the authors should be presented in order that they appear in thepublished article or book. If they are within closed parentheses, use the ampersand (&) between them. If not enclosed in parentheses, then use expanded “and”. For example:One of the biggest challenges for his research is Relevance Theory (Sperber & Wilson, 1986).Sperber and Wilson (1986) propose the definition of relevance: an assumption is relevant in a context if and only if it has some contextual effect in that context.⏹If an article has three to five authors, the first reference to the article includes all authors andsubsequent citations in the same document may refer to the article by the principal author plus “et al.” All authors must be present in the references section. For example:Blutner, Leßmöllmann and van der Sandt (1996) first used the term Lexical Pragmatics.Blutner et al. (1996) argued that lexical pragmatics is a research field that aims to give a systematic and explanatory account of pragmatic phenomena that are connected with the semantic underspecification of lexical items.⏹If an author has multiple works that you wish to cite, separate the years of publication inchronological order with a comma. If the works are published in the same year, use suffixes a, b, c, etc. (note that corresponding letters should be used in the reference list, and these references should be ordered alphabetically by title). For example:I shall not discuss either enrichment account of the intuitive data, not because it is not topical(it clearly is), but because I have discussed such accounts in detail already (Stanley, 2002a, 2002b).As Davidson (1967a, 1967b, 1984) noted, there seem to be counterexamples to his hypothesis that there are Tarski-style theories of truth for natural languages.⏹If different authors have multiple works that you wish to cite, follow the rules for one authorabove, and use a semicolon to separate articles. Citation should first be in alphabetical order of the author, then chronological within author. For example:This idea has been enormously influential in formal semantics, although it has come in for detailed criticism by various philosophers (Soames, 1987; King, 1994, 1995, 1998).⏹For direct quotes, the format is (Author, Year, Page Number) or Author (Year, Page Number).For example:Be that as it may, the minimal proposition is said to be …available to the hearer, even if not actually accessed‟ (Bach, 1994, p.158).To illustrate that point, let us consider another contextualist example from Searle (1983, p.145).Sample in-text citationsApes and Language: A Review of the LiteratureOver the past thirty years, researchers have demonstrated that the great apes (chimpanzees, gorillas, and orangutans) resemble humans in language abilities more than had been thought possible. Just how far that resemblance extends, however, has been a matter of some controversy. Researchers agree that the apes have acquired fairly large vocabularies in American Sign Language and in artificial languages, but they have drawn quite different conclusions in addressing the following questions:1. How spontaneously have apes used language?2. How creatively have apes used language?3. Can apes create sentences?4. What are the implications of the ape language studies?This review of the literature on apes and language focuses on these four questions.How Spontaneously Have Apes Used Language?In an influential article, Terrace, Petitto, Sanders, and Bever (1979) argued that the apes in language experiments were not using language spontaneously but were merely imitating their trainers, responding to conscious or unconscious cues. Terrace and his colleagues at Columbia University had trained a chimpanzee, Nim, in American Sign Language, so their skepticism about the apes‟ abilities received much attention. In fact, funding for ape language research was sharply reduced following publication of their 1979 article “Can an Ape Create a Sentence?”In retrospect, the conclusions of Terrace et al. seem to have been premature. Although some early ape language studies had not been rigorously controlled to eliminate cuing, even as early as the 1970s R. A. Gardner and B. T. Gardner were conducting double-blind experiments that prevented any possibility of cuing (Fouts, 1997, p. 99). Since 1979, researchers have diligently guarded against cuing. For example, Lewin (1991) reported that instructions for bonobo (pygmy chimpanzee) Kanzi were “delivered by someone out of his sight,” with other team members wearing earphones so that they “could not hear the instructions and so could not cue Kanzi, even unconsciously” (p. 51). More recently,philosopher Stuart Shanker of York University has questioned the emphasis placed on cuing, pointing out that since human communication relies on the ability to understand cues and gestures in a social setting, it is not surprising that apes might rely on similar signals (Johnson, 1995).There is considerable evidence that apes have signed to one another spontaneously, without trainers present. Like many of the apes studied, gorillas Koko and Michael have been observed signing to one another (Patterson & Linden, 1981). At Central Washington University the baby chimpanzee Loulis, placed in the care of the signing chimpanzee Washoe, mastered nearly fifty signs in American Sign Language without help from humans. “Interestingly,” wrote researcher Fouts (1997), “Loulis did not pick up any of the seven signs that we [humans] used around him. He learned only from Washoe and [another chimp] Ally” (p. 244).The extent to which chimpanzees spontaneously use language may depend on their training. Terrace trained Nim using the behaviorist technique of operant conditioning, so it is not surprising that many of Nim‟s signs were cued. Many other researchers have used a conversational approach that parallels the process by which human children acquire language. In an experimental study, O‟Sullivan and Yeager (1989) contrasted the two techniques, using Terrace‟s Nim as their subject. They found that Nim‟s use of language was significantly more spontaneous under conversational conditions.How Creatively Have Apes Used Language?There is considerable evidence that apes have invented creative names. One of the earliest and most controversial examples involved the Gardners‟ chimpanzee Washoe. Washoe, who knew signs for “water” and“bird,” once signed “water bird” when in the presence of a swan. Terrace et al. (1979) suggested that there was “no basis for concluding that Washoe was characterizing the swan as a …bird that inhabits water.‟” Washoe may simply have been “identifying cor rectly a body of water and a bird, in that order” (p. 895).Other examples are not so easily explained away. The bonobo Kanzi has requested particular films by combining symbols in a creative way. For instance, to ask for Quest for Fire, a film about early primates discovering fire, Kanzi began to use symbols for “campfire”and “TV” (Eckholm, 1985). And the gorilla Koko has a long list of creative names to her credit: “elephant baby” to describe a Pinocchio doll, “finger bracelet”to describe a ring, “bottle match” to describe acigarette lighter, and so on (Patterson & Linden, 1981, p.146). If Terrace‟s analysis of the “water bird” example is applied to the examples just mentioned, it does not hold. Surely Koko did not first see an elephant and then a baby before signing “elephant baby”–or a bottle and a match before signing “bottle match.”Can Apes Create Sentences?The early ape language studies offered little proof that apes could combine symbols into grammatically ordered sentences. Apes strung together various signs, but the sequences were often random and repetitious. Nim‟s series of 16 signs is a case in point:“give orange me give eat orange me eat orange give me eat orange give me you” (Terrace et al., 1979, p. 895).More recent studies with bonobos at the Yerkes Primate Research Center in Atlanta have broken new ground. Kanzi, a bonobo trained by Savage-Rumbaugh, seems to understand simple grammatical rules about lexigram order. For instance, Kanzi learned that in two-word utterances action precedes object, an ordering also used by human children at the two-word stage. In a major article reporting on their research, Greenfield and Savage-Rumbaugh (1990) wrote that Kanzi rarely “repeated himself or formed combinations that were semantically unrelated” (p. 556).More important, Kanzi began on his own to create certain patterns that may not exist in English but can be found among deaf children and in other human languages. For example, Kanzi used his own rules when combining action symbols. Lexigrams that involved an invitation to play, such as “chase,” would appear first;lexigrams that indicated what was to be done during play (“hide”) would appear second. Kanzi also created his own rules when combining gestures and lexigrams. He would use the lexigram first and then gesture, a practice often followed by young deaf children (Greenfield & Savage-Rumbaugh, 1990, p. 560).In a recent study, Kanzi‟s abilities were shown to be similar to those of a 2-1/2-year-old human, Alia. Rumbaugh (1995) reported that “Kanzi‟s comprehension of over 600 novel sentences of request was very comparable to Alia‟s; both complied with the requests without assistance on approximately 70% of the sentences” (p. 722).What Are the Implications of the Ape Language Studies?Kanzi‟s li nguistic abilities are so impressive that they may help us understand how humans came to acquire language. Pointing out that 99% of our genetic material is held in common with the chimpanzees, Greenfield and Savage-Rumbaugh (1990) have suggested that something of the “evolutionary root of human language”can be found in the “linguistic abilities of the great apes” (p. 540). Noting that apes‟ brains are similar to those of our human ancestors, Leakey and Lewin (1992) argued that in ape brains “the cognitive foundations on which human language could be built are already present” (p. 244).The suggestion that there is a continuity in the linguistic abilities of apes and humans has created much controversy. Linguist Noam Chomsky has strongly asserted that language is a unique human characteristic (Booth, 1990). Terrace has continued to be skeptical of the claims made for the apes, as have Petitto and Bever, coauthors of the 1979 article that caused such skepticism earlier (Gibbons, 1991).Recently, neurobiologists have made discoveries that may cause even the skeptics to take notice. Ongoing studies at the Yerkes Primate Research Center have revealed remarkable similarities in the brains of chimpanzees and humans. Through brain scans of live chimpanzees, researchers have found that, as with humans, “the language-controlling PT [planum temporale] islarger on the left side of the chimps‟ brain than on the right. But it is not lateralized in monkeys, which are less closely related to humans than apes are” (Begley, 1998, p. 57).Although the ape language studies continue to generate controversy, researchers have shown over the past thirty years that the gap between the linguistic abilities of apes and humans is far less dramatic than was once believed.ReferencesBegley, S. (1998, January 19). Aping language. Newsweek 131, 56-58.Booth, W. (1990, October 29). Monkeying with language: Is chimp using words or merely aping handlers? The Washington Post, p. A3.Eckholm, E. (1985, June 25). Kanzi the chimp: A life in science. The New York Times, pp. C1, C3. Fouts, R. (1997). Next of kin: What chimpanzees taught me about who we are. New York: William Morrow.Gibbons, A. (1991). Déjà vu all over again: Chimplanguage wars. Science, 251, 1561-1562. Greenfield, P. M., & Savage-Rumbaugh, E. S. (1990). Grammatical combination in Pan paniscus: Processes of learning and invention in the evolution and development of language. In S. T.Parker & K. R. Gibson (Eds.), “Language” and intelligence in monkeys and apes: Comparative developmental perspectives (pp. 540–578). Cambridge: Cambridge University Press.Johnson, G. (1995, June 6). Chimp talk debate: Is it really language? The New York Times [Online], pp. C1, C10. Available: /~johnson/articles.chimp.html [2 February 1998].Leakey, R., & Lewin, R. (1992). Origins reconsidered: In search of what makes us human. New York: Doubleday.Lewin, R. (1991, April 29). Look who‟s talking now. New Scientist, 130, 49-52.O‟Sullivan, C., & Yeager, C. P. (1989). Communicative context and linguistic competence: The effect of social setting on a chimpanzee‟s conversational skill. In R. A. Gardner, B. T.Gardner, & T. E. Van Cantfort (Eds.), Teaching sign language to chimpanzees (pp. 269-279).Albany: SUNY Press.Patterson, F., & Linden, E. (1981). The education of Koko. New York: Holt, Rinehart & Winston. Rumbaugh, D. (1995). Primate language and cognition: Common ground. Social Research, 62, 711-730.Terrace, H. S., Petitto, L. A., Sanders, R. J., & Bever, T. G. (1979). Can an ape create a sentence?Science, 206, 891-902.。
大五人格模型和大三人格模型的比较
LOOKING BEYOND THE FIVE-FACTOR MODEL: COLLEGE SELF-EFFICACY AS A MODERATOR OF THE RELATIONSHIPBETWEEN TELLEGEN’S BIG THREE MODEL OF PERSONALITY AND HOLLAND’S MODEL OF VOCATIONAL INTEREST TYPESBy Elizabeth A BarrettThe Five-Factor Model (FFM) of personality and Tellegen’s Big Three Model of personality were compared to determine their ability to predict Holland’s RIASEC interest types. College self-efficacy was examined as a moderator of the relationship between Tellegen’s Big Three model and the RIASEC interest types. A sample of 194 college freshmen (i.e., less than 30 credits completed) was drawn from the psychology participant pool of a mid-sized Midwestern university. Instruments included the International Personality Item Pool (IPIP) to measure the FFM; the Multidimensional Personality Questionnaire Brief Form (MPQ-BF) to measure Tellegen’s Big Three model of personality; the College Self-Efficacy Inventory (CSEI) to measure college self-efficacy; and the Self Directed Search (SDS) to measure Holland’s RIASEC model of vocational interests. Findings from correlational analyses supported previous research regarding relationships among the FFM and the RIASEC interest types, and relationships among Tellegen’s Big Three and the RIASEC interest types. As hypothesized and tested via regressions for each of the six interest types, Tellegen’s Big Three model predicted all six vocational interests types (p < .001 for all), while the FFM only predicted two types at p < .05. College self-efficacy did not moderate the relationship between Tellegen’s Big Three and the RIASEC interest types. Implications and future research are discussed.ACKNOWLEDGEMENTSSeveral people have assisted me with the completion of this thesis, and I wish to thank the following people for their help and guidance:In acknowledgement of excellent guidance of this project, Dr. McFadden chairperson, whose knowledge and encouragement pushed the progress of this thesis and my development as a writer and researcher.Dr. Adams and Dr. Miron, committee members, who graciously gave their time and shared their expertise in the completion of this project, specifically, Dr. Adams who aided with the data analysis of this project and worked through multiple analysis problems with me.iiTABLE OF CONTENTSPage INTRODUCTION (1)THEORY AND LITERATURE REVIEW (4)Personality Traits and Vocational Interests Defined (4)The Five-Factor Model (FFM) of Personality (4)Holland’s Theory of Vocational Interest Types (5)Overlap between the FFM and RIASEC (7)Criticisms and Limitations of the FFM (9)Looking Beyond the FFM: Tellegen’s Big Three Model of Personality (11)Comparing Tellegen’s Big Three and the FFM (14)College Self-Efficacy: Moderating Role (16)Conclusion (20)METHOD (22)Participants (22)Procedure (23)Measures (23)Methods of Data Analysis and Missing Data (27)RESULTS (29)Descriptive Statistics (29)Relationship between the FFM and the RIASEC Interest Types:Hypothesis 1a-1e (29)Relationship between Tellegen’s Big Three and the RIASEC InterestTypes: Hypothesis 2a-2c (30)Comparing the FFM and Tellegen’s Big Three: Hypothesis 3 (31)College Self-Efficacy as Moderator: Hypothesis 4 (32)iiiTABLE OF CONTENTS (continued) DISCUSSION (34)The Relationship between the FFM and the RIASEC Interest Types (34)The Relationship between Tellegen’s Big Three and the RIASECInterest Types (35)Comparing Tellegen’s Big Three and the FFM (36)College Self-Efficacy as a Moderator (37)Limitations (38)Implications and Future Research (39)Conclusions (41)APPENDIXES (42)Appendix A: Tables (42)Table A-1. Holland’s Vocational Personality Types Described: RIASEC.. 43 Table A-2. Overlap Between the FFM and RIASEC (44)Table A-3. The Big Three of Tellegen measured by the MPQ: HigherOrder and Primary Trait Scales (45)Table A-4. Means, Standard Deviations, and Intercorrelations (47)Table A-5. Regression Analysis: Realistic Interest Type as DependentVariable (48)Table A-6. Regression Analysis: Investigative Interest Type as DependentVariable (48)Table A-7. Regression Analysis: Artistic Interest Type as DependentVariable (49)Table A-8. Regression Analysis: Social Interest Type as DependentVariable (49)Table A-9. Regression Analysis: Enterprising Interest Type as DependentVariable (50)Table A-10. Regression Analysis: Conventional Interest Type asDependent Variable (50)Table A-11. Hierarchical Multiple Moderated Regression Analysis:Realistic Interest Type as Dependent Variable (51)Table A-12. Hierarchical Multiple Moderated Regression Analysis:Investigative Interest Type as Dependent Variable (51)Table A-13. Hierarchical Multiple Moderated Regression Analysis:Artistic Interest Type as Dependent Variable (52)Table A-14. Hierarchical Multiple Moderated Regression Analysis: SocialInterest Type as Dependent Variable (52)Table A-15. Hierarchical Multiple Moderated Regression Analysis:Enterprising Interest Type as Dependent Variable (53)ivTABLE OF CONTENTS (continued)Table A-16. Hierarchical Multiple Moderated Regression Analysis:Conventional Interest Type as Dependent Variable (53)Appendix B: Figure (54)Figure B-1. Holland’s Hexagonal Model (55)Appendix C: Information Sheet and Surveys (56)REFERENCES (73)vINTRODUCTIONPersonality traits and vocational interests are two major individual difference domains that influence numerous outcomes associated with work and life success. For example, research has shown that congruence between personality traits and one’s vocation is related to greater job performance and job satisfaction (Barrick, Mount, & Judge, 2001; Hogan & Blake, 1999; Zak, Meir, & Kraemer, 1979). Additionally, specific personality traits are hypothesized to play a role in determining job success within related career domains (Sullivan & Hansen, 2004). Personality is a relatively enduring characteristic of an individual, and therefore could serve as a stable predictor of why people choose particular jobs and careers.Personality traits and vocational interests are linked by affecting behavior through motivational processes (Holland, 1973, 1985). Personality traits and vocational interests influence choices individuals make about which tasks and activities to engage in, how much effort to exert on those tasks, and how long to persist with those tasks (Holland, 1973, 1985; Mount, Barrick, Scullen, & Rounds, 2005). Research has shown that when individuals are in environments congruent with their interests, they are more likely to be happy because their beliefs, values, interests, and attitudes are supported and reinforced by people who are similar to them (Mount, Barrick, Scullen, & Rounds, 2005). Furthermore, research has demonstrated that personality and interests may shape career decision making and behavior; personality and interests guide the development ofknowledge and skills by providing the motivation to engage in particular types of activities (Sullivan & Hansen, 2004).As relatively stable dispositions, personality traits influence an individual’s behavior in a variety of life settings, including work (Dilchert, 2007). Individuals often prefer jobs requiring them to display behaviors that match their stable tendencies. Thus individuals will indicate a liking for occupations for which job duties and job environments correspond to their personality traits. Such a match between personal tendencies and job requirements can support adjustment and eventually occupational success, making the choice of a given job personally rewarding on multiple levels (Dilchert, 2007).People applying for jobs need to try to understand themselves more fully in order to determine if they will be satisfied with their career choices based on their personality traits. This process can be aided by vocational counselors who conduct vocational assessments. The purpose of vocational assessment is to enhance client self-understanding, promote self-exploration, and assist in realistic decision making (Carless, 1999). According to a model proposed by Carless (1999), career assessment is based on the assumption that comprehensive information about the self (e.g., knowledge of one’s personality) in relation to the world of work is a necessary prerequisite for wise career decision making.Self-efficacy beliefs--personal expectations about the ability to succeed at tasks (Bandura, 1986)--are often assessed by vocational counselors. This study examines college self-efficacy--belief in one’s ability to perform tasks necessary for success incollege (Wang & Castaneda-Sound, 2008). Self-efficacy determines the degree to which individuals initiate and persist with tasks (Bandura, 1986), and research has found that personality may influence exploration of vocational interests, through high levels of self-efficacy (Nauta, 2007).There is an abundance of literature supporting that the Five-Factor Model (FFM) (discussed in depth in following sections) of personality predicts Holland’s theory of vocational interest types; however, there is little literature that extends beyond use of the Five-Factor Model. This is due to the adoption of the FFM as an overriding model of personality over the past fifteen years. However, as will be demonstrated later, several criticisms of the model have surfaced. In light of these criticisms the purpose of this study is to extend the existing literature that has established links between the FFM and Holland’s vocational interest types, while examining the relationship between an alternate personality model, Tellegen’s Big Three (as measured by the Multidimensional Personality Questionnaire (MPQ)) and Holland’s types. Furthermore, this study will examine the moderating role that college self-efficacy plays on the relationship between Tellegen’s Big Three and Holland’s interest types.THEORY AND LITERATURE REVIEWPersonality Traits and Vocational Interests DefinedPersonality traits refer to characteristics that are stable over time and are psychological in nature; they reflect who we are and in aggregate determine our affective, behavioral, and cognitive styles (Mount, Barrick, Scullen, & Rounds, 2005). Vocational interests reflect long-term dispositional traits that influence vocational behavior primarily through one’s preferences for certain environments, activities, and types of people (Mount, Barrick, Scullen, & Rounds, 2005).The Five-Factor Model (FFM) of PersonalityThe FFM, often referred to as the Big Five personality dimensions, is a major model that claims personality consists of five dimensions: Openness to Experience (i.e., imaginative, intellectual, and artistically sensitive), Conscientiousness (i.e., dependable, organized, and persistent), Extraversion (i.e., sociable, active, and energetic), Agreeableness (i.e., cooperative, considerate, and trusting), and Neuroticism, sometimes referred to positively as emotional stability (i.e., calm, secure, and unemotional) (Harris, Vernon, Johnson, & Jang, 2006; McCrae & Costa, 1986; McCrae & Costa, 1987; Mount, Barrick, Scullen, & Rounds, 2005; Nauta, 2004; Sullivan & Hansen, 2004). The FFM provides the foundation for several personality measures (e.g., NEO-PI, NEO-PI-R, NEO-FFI) that have proved to be valid and reliable and are widely utilized in research today (Costa & McCrae, 1992). There appears to be a large degree of consensusregarding the FFM of personality and the instruments used to measure the model. For instance, the FFM has been shown to have a large degree of universality (McCrae, 2001), specifically in terms of stability across adulthood (McCrae & Costa, 2003) and cultures (DeFruyt & Mervielde, 1997; Hofstede & McCrae, 2004, McCrae, 2001).Holland’s Theory of Vocational Interest TypesHolland’s theory of vocational interests has played a key role in efforts to understand vocational interests, choice, and satisfaction.Holland was very clear that he believed personality and vocational interests are related:If vocational interests are construed as an expression of personality, then theyrepresent the expression of personality in work, school subjects, hobbies,recreational activities, and preferences. In short, what we have called ‘vocational interests’ are simply another aspect of personality…If vocational interests are anexpression of personality, then it follows that interest inventories are personalityinventories. (Holland, 1973, p.7)Vocational interest types, as classified by Holland, are six broad categories (discussed later in the section) that can be used to group occupations or the people who work in them. Holland’s theory of vocational interest types and work environments states that employees’ satisfaction with a job as well as propensity to leave that job depends on the degree to which their personalities match their occupational environments (Holland, 1973, 1985). Furthermore, people are assumed to be most satisfied, successful, and stable in a work environment that is congruent with their vocational interest type. Two ofHolland’s basic assumptions are: (a) individuals in a particular vocation have similar personalities, and (b) individuals tend to choose occupational environments consistent with their personality (Holland, 1997).A fundamental proposition of Holland’s theory is that, when differentiated by their vocational interests, people can be categorized according to a taxonomy of six types, hereinafter collectively referred to as RIASEC (Holland, 1973, 1985). Holland’s theory states that six vocational interest types--Realistic, Investigative, Artistic, Social, Enterprising, and Conventional (RIASEC)--influence people to seek environments which are congruent with their characteristics (Harris, Vernon, Johnson, & Jang, 2006; Holland, 1973, 1985; Nauta, 2004; Roberti, Fox, & Tunick, 2003; Sullivan & Hansen, 2004; Zak, Meir, & Kraemer, 1979). Holland used adjective descriptors to capture the distinctive characteristics of each interest type (Hogan & Blake, 1999). These are summarized in Table A-1. Holland’s approach to the assessment of vocational interest types was based on the assumption that members of an occupational group have similar work-related preferences and respond to problems and situations in similar ways (Carless, 1999).Realistic types like the systematic manipulation of machinery, tools, or animals. Investigative types have interests that involve analytical, curious, methodical, and precise activities. The interests of Artistic types are expressive, nonconforming, original, and introspective. Social types want to work with and help others. Enterprising types seek to influence others to attain organizational goals or economic gain. Finally, Conventional types are interested in systematic manipulation of data, filing records, or reproducing materials (Tokar, Vaux, & Swanson, 1995).According to Holland’s theory, these interest types differ in their relative similarity to one another, in ways that can be represented by a hexagonal figure with the types positioned at the six points (see Figure B-1). Adjacent types (e.g., Realistic and Investigative) are most similar; opposite types (e.g., Realistic and Social) are least similar, and alternating types (e.g., Realistic and Artistic) are assumed to have an intermediate level of relationship (Holland, 1973, 1985; Tokar, Vaux, & Swanson, 1995).Overlap between the FFM and RIASECMany studies provide evidence of the links between the FFM of personality and the RIASEC interest types. An extensive review of the research investigating the links between the FFM and the RIASEC types identified ten studies that found Extraversion predicts interest in jobs that focus on Social and Enterprising interests. Ten studies showed Openness to Experience predicts interest in jobs that focus on Investigative and Artistic interests. Six studies found Agreeableness predicts interest in jobs that focus on Social interest; six studies showed Conscientiousness predicts interests in jobs that focus on Conventional interests; and one study found Neuroticism predicts interests in jobs that focus on Investigative interests (see Table A-2 for the citations). One discrepancy in this research has been Costa and McCrae’s claims that the FFM applies uniformly to all adult ages, but Mroczek, Ozer, Spiro, and Kaiser (1998) found substantial differences between the structures emerging from older individuals as compared to undergraduate students, in that the five factor structure failed to emerge in the student sample (i.e., agreeableness failed to emerge) as it did with the older sample.All of the links discussed between the FFM of personality and the RIASEC interest types provide the foundation for hypotheses 1a – 1e. Hypotheses 1a – 1e will add to the literature, previously discussed, by assessing current college students early in their college careers. These are the people who have the potential to be most influenced by vocational and career counselors. Given that research has found a discrepancy in FFM profiles of younger and older individuals, it is important to test its efficacy in predicting vocational interests.Hypothesis 1a (H1a): Extraversion will significantly positively correlate withSocial and Enterprising types, but not Realistic, Investigative, Artistic, andConventional types.Hypothesis 1b (H1b): Openness to Experience will significantly positivelycorrelate with Investigative and Artistic types, but not Realistic, Conventional,Social, and Enterprising types.Hypothesis 1c (H1c): Agreeableness will significantly positively correlate withSocial types, but not Realistic, Conventional, Enterprising, Investigative, andArtistic types.Hypothesis 1d (H1d): Conscientiousness will significantly positively correlatewith Conventional types, but not Realistic, Enterprising, Investigative, Social, and Artistic types.Hypothesis 1e (H1e): Neuroticism will significantly negatively correlate withInvestigative types, but not Realistic, Enterprising, Conventional, Social, andArtistic types.Criticisms and Limitations of the FFMThe whole enterprise of science depends on challenging accepted views, and the FFM has become one of the most accepted models in personality research. Many critiques of the FFM ask “Why are there five and only five factors? Five factor protagonists say: it is an empirical fact…via the mathematical method of factor analysis, the basic dimensions of personality have been discovered.” (McCrae & Costa, 1989, p. 120). Has psychology as a science achieved a final and absolute way of looking at personality or is there a way to further our conceptualization of personality? In the article by Costa and McCrae (1997) explaining the anticipated changes to the NEO in the new millennium, they anticipate only minor wording modifications and simplifications. Thus it appears as if the FFM is viewed as a final or almost final achievement (Block, 2001). One claimed benefit of the FFM is evidence of heritability is strong for all 5 factors, but evidence is strong for all personality factors studied; it does not single out the Costa and McCrae factors (Eysenck, 1992). In other words, all the criteria suggested by Costa and McCrae are necessary but not sufficient to mark out one model from many which also conform to this criteria.The debate that has been most prominent over the past 15 years, and which has probably attracted the most attention, concerns the number and description of the basic, fundamental, highest-order factors of personality. Evidence from meta-analyses of factorial studies provide evidence that three, not five personality factors, emerge at the highest level of analysis (Royce & Powell, 1983; Tellegen & Waller, 1991; Zuckerman, Kuhlman, & Camac, 1988; Zuckerman, Kuhlman, Thornquist, & Kiers, 1991).Altogether, Eysenck (1992) has surveyed many different models, questionnaires and inventories, reporting in most cases a break-down into 2 or 3 major factors; but never 5. Additionally, Jackson, Furnham, Forde, and Cotter (2000) and Tellegen (1985) have contradicted Costa and McCrae’s (1995) assertions that a five-factor model seems most appropriate, with results showing that a three-factor solution is both more clear and parsimonious.Another critique of the FFM lies in its development. The initial factor-analytic derivations of the Big Five were not guided by explicit psychological theory, and therefore some have asked the question, “Why these five?” (e.g., Revelle, 1987; Waller & Ben-Porath, 1987). As Briggs (1989) points out, the original studies leading to the FFM “prompted no a priori predictions as to what factors should emerge, and a coherent and falsifiable explanation for the five factors has yet to be put forward” (p. 249).A further developmental critique of the FFM is the lack of lower order factors. Theoretically, factors exist at different hierarchical levels, and the FFM only measures five higher order factors (Block, 2001). The FFM operates at a broadband level to measure the main (i.e., higher order) categories of traits (McAdams, 1992). Within each of the five categories, therefore, may be many different and more specific traits, as traits are nested hierarchically within traits (McAdams, 1992).Another limitation of the FFM lies in researchers’ inability to consistently link the personality traits to the Holland interest types. Research has found that although there is a significant overlap between the FFM and RIASEC interest types, the RIASEC types do not appear to be entirely encompassed by the Big-Five personality dimensions (Carless,1999; Church, 1994; DeFruyt & Mervielde, 1999; Tokar, Vaux, & Swanson, 1995). Three personality dimensions in the FFM predict the RIASEC types, but there is less evidence to support that the other two predict the RIASEC types. Specifically, there appears to be significant overlap with Conscientiousness, Openness, and Extraversion in predicting the RIASEC interest types, but less research has been able to find links between Agreeableness and Neuroticism with the RIASEC interest types. This is a limitation of the FFM in relating to vocational interests (Costa, McCrae, & Holland, 1984; Gottfredson, Jones, & Holland, 1993; Tokar, Vaux, & Swanson, 1995).Looking Beyond the FFM: Tellegen’s Big Three Model of PersonalityIn light of these criticisms of the FFM, it seems attention could be paid to alternate models of personality to investigate the dimensions underlying Holland’s interest types. The literature base is sparse here, and alternative personality models warrant further study, particularly with regard to vocational interests (Blake & Sackett, 1999; Church, 1994; Larson & Borgen, 2002; Staggs, Larson, & Borgen, 2003). One such model is Tellegen’s Big Three which addresses many of the criticisms of the FFM.Many vocational psychology researchers use the Big Five model of personality, often measured by the NEO-PI or NEO-PI-R, but less often the Big Three model of personality measured by the Multidimensional Personality Questionnaire (MPQ) is used (Tellegen, 1985; Tellegen & Waller, 1991). This model of personality resulted from ten years of research on focal dimensions in the personality literature (Tellegen, 1985; Tellegen & Waller, 1991). Tellegen’s (1985; Tellegen & Waller, 1991) Big Three modeldefines three higher order factors. These represent the clusters of items from a factor analysis that composed the three higher order traits. The lower order factors consist of items clustered in each of the higher order factors. The higher order factors are: Positive Emotionality (PEM), Negative Emotionality (NEM), and Constraint (CT) (Tellegen, 1985; Tellegen & Waller, 1991). These higher order traits correlate minimally with one another and encompass 11 lower order traits. Refer to Table A-3 for a description of the three higher order traits and the 11 lower order traits.There are only three published studies that have examined the Big Three model as relating to vocational interests. Blake and Sackett (1999) reported that the Artistic type moderately related with the MPQ Absorption lower order trait (Larson & Borgen, 2002). The Social type negatively related to the MPQ Aggression lower order trait; the Enterprising type related moderately to the MPQ Social Potency lower order trait; and the Conventional type related moderately to the MPQ Control lower order trait.Staggs, Larson, and Borgen (2003) also analyzed the lower order traits, specifically, as opposed to the higher order factors of PEM, NEM, and CT. They identified seven personality dimensions that have a substantial relationship with vocational interests: Absorption predicted interest in Artistic occupations; Social Potency predicted interest in Enterprising occupations; Harm Avoidance predicted interest in science and mechanical activity occupations; Achievement predicted interest in science and mathematic occupations; Social Closeness predicted interest in mechanical activity occupations; Traditionalism predicted interest in religious activities; and Stress Reaction predicted interest in athletic careers. Staggs, Larson, and Borgen (2003) used a collegestudent sample, but were not studying the RIASEC types; they were using a different conceptualization of vocational interests as measured by the Strong Interest Inventory which measures General Occupational Themes.Larson and Borgen (2002) found that the PEM factor was more strongly correlated with Social interests than with Enterprising interests; however, PEM did strongly correlate with all six RIASEC types (p < .001). This finding shows strong evidence that the PEM higher order trait relates to the RIASEC types. Larson and Borgen (2002) also found that the CT factor was negatively related to Realistic and Artistic interest types, and that the NEM factor was negatively related to Artistic interest types. Larson and Borgen (2002) utilized a sample of “gifted” adolescent students, which is a very limited and non-generalizable sample. In contrast, the current study tests a freshman college student sample, which is more generalizable to the population of students who are seeking vocational guidance.The links between the MPQ and the RIASEC interest types are under-researched. Although some vocational research has utilized the MPQ, more needs to be done to determine the relationships between Tellegen’s Big Three and Holland’s RIASEC interest types. However, the research provides support for the idea that there are alternative personality dimensions (i.e., Tellegen’s Big Three), outside of the FFM, that can significantly predict vocational interests, in particular the RIASEC types. Hypotheses 2a – 2c will test relationships between the Tellegen’s Big Three (as measured by the MPQ-BF) and the RIASEC interest types.Hypothesis 2a (H2a): The PEM factor will significantly positively correlate with all six RIASEC types.Hypothesis 2b (H2b): The CT factor will significantly negatively correlate withRealistic and Artistic types, but not with Investigative, Social, Enterprising, andConventional types.Hypothesis 2c (H2c): The NEM factor will significantly negatively correlate with Artistic types, but not with Investigative, Social, Enterprising, Realistic, andConventional types.Comparing Tellegen’s Big Three and the FFMAn earlier discussion proposed criticisms of the FFM. In light of these criticisms an alternate personality model was considered: Tellegens’ Big Three, measured by the MPQ. This model of personality resolves all the previous criticisms of the FFM: five versus 3 factors, lack of lower order factors, and model development issues.Tellegen’s (1985) understanding of personality differs from the conception of the FFM. Tellegen believes personality can be summed by three overriding traits or factors versus the 5 factors of the FFM. This is an inherent difference in the two models of personality, which guided the development of instruments used to measure these models, in terms of a three versus a five factor structure. Furthermore, Tellegen (1985) utilized a bottom-up approach to development of the MPQ, in which constructs were based on iterative cycles of data collection and item analyses designed to better differentiate the primary scales. In contrast, Tupes and Chrtistal (1961) emphasized deductive, top-down。
胺基保护——邻苯二甲酰亚胺脱保护
New1H-Pyrazole-Containing Polyamine Receptors Able ToComplex L-Glutamate in Water at Physiological pH ValuesCarlos Miranda,†Francisco Escartı´,‡Laurent Lamarque,†Marı´a J.R.Yunta,§Pilar Navarro,*,†Enrique Garcı´a-Espan˜a,*,‡and M.Luisa Jimeno†Contribution from the Instituto de Quı´mica Me´dica,Centro de Quı´mica Orga´nica Manuel Lora Tamayo,CSIC,C/Juan de la Cier V a3,28006Madrid,Spain,Departamento de Quı´mica Inorga´nica,Facultad de Quı´mica,Uni V ersidad de Valencia,c/Doctor Moliner50, 46100Burjassot(Valencia),Spain,and Departamento de Quı´mica Orga´nica,Facultad deQuı´mica,Uni V ersidad Complutense de Madrid,A V plutense s/n,28040Madrid,SpainReceived April16,2003;E-mail:enrique.garcia-es@uv.esAbstract:The interaction of the pyrazole-containing macrocyclic receptors3,6,9,12,13,16,19,22,25,26-decaazatricyclo-[22.2.1.111,14]-octacosa-1(27),11,14(28),24-tetraene1[L1],13,26-dibenzyl-3,6,9,12,13,16,-19,22,25,26-decaazatricyclo-[22.2.1.111,14]-octacosa-1(27),11,14(28),24-tetraene2[L2],3,9,12,13,16,22,-25,26-octaazatricyclo-[22.2.1.111,14]-octacosa-1(27),11,14(28),24-tetraene3[L3],6,19-dibenzyl-3,6,9,12,13,-16,19,22,25,26-decaazatricyclo-[22.2.1.111,14]-octacosa-1(27),11,14(28),24-tetraene4[L4],6,19-diphenethyl-3,6,9,12,13,16,19,22,25,26-decaazatricyclo-[22.2.1.111,14]-octacosa-1(27),11,14(28),24-tetraene5[L5],and 6,19-dioctyl-3,6,9,12,13,16,19,22,25,26-decaazatricyclo-[22.2.1.111,14]-octacosa-1(27),11,14(28),24-tetra-ene6[L6]with L-glutamate in aqueous solution has been studied by potentiometric techniques.The synthesis of receptors3-6[L3-L6]is described for the first time.The potentiometric results show that4[L4]containing benzyl groups in the central nitrogens of the polyamine side chains is the receptor displaying the larger interaction at pH7.4(K eff)2.04×104).The presence of phenethyl5[L5]or octyl groups6[L6]instead of benzyl groups4[L4]in the central nitrogens of the chains produces a drastic decrease in the stability[K eff )3.51×102(5),K eff)3.64×102(6)].The studies show the relevance of the central polyaminic nitrogen in the interaction with glutamate.1[L1]and2[L2]with secondary nitrogens in this position present significantly larger interactions than3[L3],which lacks an amino group in the center of the chains.The NMR and modeling studies suggest the important contribution of hydrogen bonding andπ-cation interaction to adduct formation.IntroductionThe search for the L-glutamate receptor field has been andcontinues to be in a state of almost explosive development.1 L-Glutamate(Glu)is thought to be the predominant excitatory transmitter in the central nervous system(CNS)acting at a rangeof excitatory amino acid receptors.It is well-known that it playsa vital role mediating a great part of the synaptic transmission.2However,there is an increasing amount of experimentalevidence that metabolic defects and glutamatergic abnormalitiescan exacerbate or induce glutamate-mediated excitotoxic damageand consequently neurological disorders.3,4Overactivation ofionotropic(NMDA,AMPA,and Kainate)receptors(iGluRs)by Glu yields an excessive Ca2+influx that produces irreversible loss of neurons of specific areas of the brain.5There is much evidence that these processes induce,at least in part,neuro-degenerative illnesses such as Parkinson,Alzheimer,Huntington, AIDS,dementia,and amyotrophic lateral sclerosis(ALS).6In particular,ALS is one of the neurodegenerative disorders for which there is more evidence that excitotoxicity due to an increase in Glu concentration may contribute to the pathology of the disease.7Memantine,a drug able to antagonize the pathological effects of sustained,but relatively small,increases in extracellular glutamate concentration,has been recently received for the treatment of Alzheimer disease.8However,there is not an effective treatment for ALS.Therefore,the preparation of adequately functionalized synthetic receptors for L-glutamate seems to be an important target in finding new routes for controlling abnormal excitatory processes.However,effective recognition in water of aminocarboxylic acids is not an easy task due to its zwitterionic character at physiological pH values and to the strong competition that it finds in its own solvent.9†Centro de Quı´mica Orga´nica Manuel Lora Tamayo.‡Universidad de Valencia.§Universidad Complutense de Madrid.(1)Jane,D.E.In Medicinal Chemistry into the Millenium;Campbell,M.M.,Blagbrough,I.S.,Eds.;Royal Society of Chemistry:Cambridge,2001;pp67-84.(2)(a)Standaert,D.G.;Young,A.B.In The Pharmacological Basis ofTherapeutics;Hardman,J.G.,Goodman Gilman,A.,Limbird,L.E.,Eds.;McGraw-Hill:New York,1996;Chapter22,p503.(b)Fletcher,E.J.;Loge,D.In An Introduction to Neurotransmission in Health and Disease;Riederer,P.,Kopp,N.,Pearson,J.,Eds.;Oxford University Press:New York,1990;Chapter7,p79.(3)Michaelis,E.K.Prog.Neurobiol.1998,54,369-415.(4)Olney,J.W.Science1969,164,719-721.(5)Green,J.G.;Greenamyre,J.T.Prog.Neurobiol.1996,48,613-63.(6)Bra¨un-Osborne,H.;Egebjerg,J.;Nielsen,E.O.;Madsen,U.;Krogsgaard-Larsen,P.J.Med.Chem.2000,43,2609-2645and references therein.(7)(a)Shaw,P.J.;Ince,P.G.J.Neurol.1997,244(Suppl2),S3-S14.(b)Plaitakis,A.;Fesdjian,C.O.;Shashidharan,S Drugs1996,5,437-456.(8)Frantz,A.;Smith,A.Nat.Re V.Drug Dico V ery2003,2,9.Published on Web12/30/200310.1021/ja035671m CCC:$27.50©2004American Chemical Society J.AM.CHEM.SOC.2004,126,823-8339823There are many types of receptors able to interact with carboxylic acids and amino acids in organic solvents,10-13yielding selective complexation in some instances.However,the number of reported receptors of glutamate in aqueous solution is very scarce.In this sense,one of the few reports concerns an optical sensor based on a Zn(II)complex of a 2,2′:6′,2′′-terpyridine derivative in which L -aspartate and L -glutamate were efficiently bound as axial ligands (K s )104-105M -1)in 50/50water/methanol mixtures.14Among the receptors employed for carboxylic acid recogni-tion,the polyamine macrocycles I -IV in Chart 1are of particular relevance to this work.In a seminal paper,Lehn et al.15showed that saturated polyamines I and II could exert chain-length discrimination between different R ,ω-dicarboxylic acids as a function of the number of methylene groups between the two triamine units of the receptor.Such compounds were also able to interact with a glutamic acid derivative which has the ammonium group protected with an acyl moiety.15,16Compounds III and IV reported by Gotor and Lehn interact in their protonated forms in aqueous solution with protected N -acetyl-L -glutamate and N -acetyl-D -glutamate,showing a higher stability for the interaction with the D -isomer.17In both reports,the interaction with protected N -acetyl-L -glutamate at physiological pH yields constants of ca.3logarithmic units.Recently,we have shown that 1H -pyrazole-containing mac-rocycles present desirable properties for the binding of dopam-ine.18These polyaza macrocycles,apart from having a highpositive charge at neutral pH values,can form hydrogen bonds not only through the ammonium or amine groups but also through the pyrazole nitrogens that can behave as hydrogen bond donors or acceptors.In fact,Elguero et al.19have recently shown the ability of the pyrazole rings to form hydrogen bonds with carboxylic and carboxylate functions.These features can be used to recognize the functionalities of glutamic acid,the carboxylic and/or carboxylate functions and the ammonium group.Apart from this,the introduction of aromatic donor groups appropriately arranged within the macrocyclic framework or appended to it through arms of adequate length may contribute to the recognition event through π-cation interactions with the ammonium group of L -glutamate.π-Cation interactions are a key feature in many enzymatic centers,a classical example being acetylcholine esterase.20The role of such an interaction in abiotic systems was very well illustrated several years ago in a seminal work carried out by Dougherty and Stauffer.21Since then,many other examples have been reported both in biotic and in abiotic systems.22Taking into account all of these considerations,here we report on the ability of receptors 1[L 1]-6[L 6](Chart 2)to interact with L -glutamic acid.These receptors display structures which differ from one another in only one feature,which helps to obtain clear-cut relations between structure and interaction(9)Rebek,J.,Jr.;Askew,B.;Nemeth,D.;Parris,K.J.Am.Chem.Soc.1987,109,2432-2434.(10)Seel,C.;de Mendoza,J.In Comprehensi V e Supramolecular Chemistry ;Vogtle,F.,Ed.;Elsevier Science:New York,1996;Vol.2,p 519.(11)(a)Sessler,J.L.;Sanson,P.I.;Andrievesky,A.;Kral,V.In SupramolecularChemistry of Anions ;Bianchi,A.,Bowman-James,K.,Garcı´a-Espan ˜a,E.,Eds.;John Wiley &Sons:New York,1997;Chapter 10,pp 369-375.(b)Sessler,J.L.;Andrievsky,A.;Kra ´l,V.;Lynch,V.J.Am.Chem.Soc.1997,119,9385-9392.(12)Fitzmaurice,R.J.;Kyne,G.M.;Douheret,D.;Kilburn,J.D.J.Chem.Soc.,Perkin Trans.12002,7,841-864and references therein.(13)Rossi,S.;Kyne,G.M.;Turner,D.L.;Wells,N.J.;Kilburn,J.D.Angew.Chem.,Int.Ed.2002,41,4233-4236.(14)Aı¨t-Haddou,H.;Wiskur,S.L.;Lynch,V.M.;Anslyn,E.V.J.Am.Chem.Soc.2001,123,11296-11297.(15)Hosseini,M.W.;Lehn,J.-M.J.Am.Chem.Soc.1982,104,3525-3527.(16)(a)Hosseini,M.W.;Lehn,J.-M.Hel V .Chim.Acta 1986,69,587-603.(b)Heyer,D.;Lehn,J.-M.Tetrahedron Lett.1986,27,5869-5872.(17)(a)Alfonso,I.;Dietrich,B.;Rebolledo,F.;Gotor,V.;Lehn,J.-M.Hel V .Chim.Acta 2001,84,280-295.(b)Alfonso,I.;Rebolledo,F.;Gotor,V.Chem.-Eur.J.2000,6,3331-3338.(18)Lamarque,L.;Navarro,P.;Miranda,C.;Ara ´n,V.J.;Ochoa,C.;Escartı´,F.;Garcı´a-Espan ˜a,E.;Latorre,J.;Luis,S.V.;Miravet,J.F.J.Am.Chem.Soc .2001,123,10560-10570.(19)Foces-Foces,C.;Echevarria,A.;Jagerovic,N.;Alkorta,I.;Elguero,J.;Langer,U.;Klein,O.;Minguet-Bonvehı´,H.-H.J.Am.Chem.Soc.2001,123,7898-7906.(20)Sussman,J.L.;Harel,M.;Frolow,F.;Oefner,C.;Goldman,A.;Toker,L.;Silman,I.Science 1991,253,872-879.(21)Dougherty,D.A.;Stauffer,D.A.Science 1990,250,1558-1560.(22)(a)Sutcliffe,M.J.;Smeeton,A.H.;Wo,Z.G.;Oswald,R.E.FaradayDiscuss.1998,111,259-272.(b)Kearney,P.C.;Mizoue,L.S.;Kumpf,R.A.;Forman,J.E.;McCurdy,A.;Dougherty,D.A.J.Am.Chem.Soc.1993,115,9907-9919.(c)Bra ¨uner-Osborne,H.;Egebjerg,J.;Nielsen,E.;Madsen,U.;Krogsgaard-Larsen,P.J.Med.Chem.2000,43,2609-2645.(d)Zacharias,N.;Dougherty,D.A.Trends Pharmacol.Sci.2002,23,281-287.(e)Hu,J.;Barbour,L.J.;Gokel,G.W.J.Am.Chem.Soc.2002,124,10940-10941.Chart 1.Some Receptors Employed for Dicarboxylic Acid and N -AcetylglutamateRecognitionChart 2.New 1H -Pyrazole-Containing Polyamine Receptors Able To Complex L -Glutamate inWaterA R T I C L E SMiranda et al.824J.AM.CHEM.SOC.9VOL.126,NO.3,2004strengths.1[L1]and2[L2]differ in the N-benzylation of the pyrazole moiety,and1[L1]and3[L3]differ in the presence in the center of the polyamine side chains of an amino group or of a methylene group.The receptors4[L4]and5[L5]present the central nitrogens of the chain N-functionalized with benzyl or phenethyl groups,and6[L6]has large hydrophobic octyl groups.Results and DiscussionSynthesis of3-6.Macrocycles3-6have been obtained following the procedure previously reported for the preparation of1and2.23The method includes a first dipodal(2+2) condensation of the1H-pyrazol-3,5-dicarbaldehyde7with the corresponding R,ω-diamine,followed by hydrogenation of the resulting Schiff base imine bonds.In the case of receptor3,the Schiff base formed by condensation with1,5-pentanediamine is a stable solid(8,mp208-210°C)which precipitated in68% yield from the reaction mixture.Further reduction with NaBH4 in absolute ethanol gave the expected tetraazamacrocycle3, which after crystallization from toluene was isolated as a pure compound(mp184-186°C).In the cases of receptors4-6, the precursor R,ω-diamines(11a-11c)(Scheme1B)were obtained,by using a procedure previously described for11a.24 This procedure is based on the previous protection of the primary amino groups of1,5-diamino-3-azapentane by treatment with phthalic anhydride,followed by alkylation of the secondary amino group of1,5-diphthalimido-3-azapentane9with benzyl, phenethyl,or octyl bromide.Finally,the phthalimido groups of the N-alkyl substituted intermediates10a-10c were removed by treatment with hydrazine to afford the desired amines11a-11c,which were obtained in moderate yield(54-63%).In contrast with the behavior previously observed in the synthesis of3,in the(2+2)dipodal condensations of7with 3-benzyl-,3-phenethyl-,and3-octyl-substituted3-aza-1,5-pentanediamine11a,11b,and11c,respectively,there was not precipitation of the expected Schiff bases(Scheme1A). Consequently,the reaction mixtures were directly reduced in situ with NaBH4to obtain the desired hexaamines4-6,which after being carefully purified by chromatography afforded purecolorless oils in51%,63%,and31%yield,respectively.The structures of all of these new cyclic polyamines have been established from the analytical and spectroscopic data(MS(ES+), 1H and13C NMR)of both the free ligands3-6and their corresponding hydrochloride salts[3‚4HCl,4‚6HCl,5‚6HCl, and6‚6HCl],which were obtained as stable solids following the same procedure previously reported18for1‚6HCl and2‚6HCl.As usually occurs for3,5-disubstituted1H-pyrazole deriva-tives,either the free ligands3-6or their hydrochlorides show very simple1H and13C NMR spectra,in which signals indicate that,because of the prototropic equilibrium of the pyrazole ring, all of these compounds present average4-fold symmetry on the NMR scale.The quaternary C3and C5carbons appear together,and the pairs of methylene carbons C6,C7,and C8are magnetically equivalent(see Experimental Section).In the13C NMR spectra registered in CDCl3solution, significant differences can be observed between ligand3,without an amino group in the center of the side chain,and the N-substituted ligands4-6.In3,the C3,5signal appears as a broad singlet.However,in4-6,it almost disappears within the baseline of the spectra,and the methylene carbon atoms C6and C8experience a significant broadening.Additionally,a remark-able line-broadening is also observed in the C1′carbon signals belonging to the phenethyl and octyl groups of L5and L6, respectively.All of these data suggest that as the N-substituents located in the middle of the side chains of4-6are larger,the dynamic exchange rate of the pyrazole prototropic equilibrium is gradually lower,probably due to a relation between proto-tropic and conformational equilibria.Acid-Base Behavior.To follow the complexation of L-glutamate(hereafter abbreviated as Glu2-)and its protonated forms(HGlu-,H2Glu,and H3Glu+)by the receptors L1-L6, the acid-base behavior of L-glutamate has to be revisited under the experimental conditions of this work,298K and0.15mol dm-3.The protonation constants obtained,included in the first column of Table1,agree with the literature25and show that the zwitterionic HGlu-species is the only species present in aqueous solution at physiological pH values(Scheme2and Figure S1of Supporting Information).Therefore,receptors for(23)Ara´n,V.J.;Kumar,M.;Molina,J.;Lamarque,L.;Navarro,P.;Garcı´a-Espan˜a,E.;Ramı´rez,J.A.;Luis,S.V.;Escuder,.Chem.1999, 64,6137-6146.(24)(a)Yuen Ng,C.;Motekaitis,R.J.;Martell,A.E.Inorg.Chem.1979,18,2982-2986.(b)Anelli,P.L.;Lunazzi,L.;Montanari,F.;Quici,.Chem.1984,49,4197-4203.Scheme1.Synthesis of the Pyrazole-Containing MacrocyclicReceptorsNew1H-Pyrazole-Containing Polyamine Receptors A R T I C L E SJ.AM.CHEM.SOC.9VOL.126,NO.3,2004825glutamate recognition able to address both the negative charges of the carboxylate groups and the positive charge of ammonium are highly relevant.The protonation constants of L 3-L 6are included in Table 1,together with those we have previously reported for receptors L 1and L 2.23A comparison of the constants of L 4-L 6with those of the nonfunctionalized receptor L 1shows a reduced basicity of the receptors L 4-L 6with tertiary nitrogens at the middle of the polyamine bridges.Such a reduction in basicity prevented the potentiometric detection of the last protonation for these ligands in aqueous solution.A similar reduction in basicity was previously reported for the macrocycle with the N -benzylated pyrazole spacers (L 2).23These diminished basicities are related to the lower probability of the tertiary nitrogens for stabilizing the positive charges through hydrogen bond formation either with adjacent nonprotonated amino groups of the molecule or with water molecules.Also,the increase in the hydrophobicity of these molecules will contribute to their lower basicity.The stepwise basicity constants are relatively high for the first four protonation steps,which is attributable to the fact that these protons can bind to the nitrogen atoms adjacent to the pyrazole groups leaving the central nitrogen free,the electrostatic repulsions between them being therefore of little significance.The remaining protonation steps will occur in the central nitrogen atom,which will produce an important increase in the electrostatic repulsion in the molecule and therefore a reduction in basicity.As stated above,the tertiary nitrogen atoms present in L 4-L 6will also contribute to this diminished basicity.To analyze the interaction with glutamic acid,it is important to know the protonation degree of the ligands at physiological pH values.In Table 2,we have calculated the percentages ofthe different protonated species existing in solution at pH 7.4for receptors L 1-L 6.As can be seen,except for the receptor with the pentamethylenic chains L 3in which the tetraprotonated species prevails,all of the other systems show that the di-and triprotonated species prevail,although to different extents.Interaction with Glutamate.The stepwise constants for the interaction of the receptors L 1-L 6with glutamate are shown in Table 3,and selected distribution diagrams are plotted in Figure 1A -C.All of the studied receptors interact with glutamate forming adduct species with protonation degrees (j )which vary between 8and 0depending on the system (see Table 3).The stepwise constants have been derived from the overall association constants (L +Glu 2-+j H +)H j LGlu (j -2)+,log j )provided by the fitting of the pH-metric titration curves.This takes into account the basicities of the receptors and glutamate (vide supra)and the pH range in which a given species prevails in solution.In this respect,except below pH ca.4and above pH 9,HGlu -can be chosen as the protonated form of glutamate involved in the formation of the different adducts.Below pH 4,the participation of H 2Glu in the equilibria has also to be considered (entries 9and 10in Table 3).For instance,the formation of the H 6LGlu 4+species can proceed through the equilibria HGlu -+H 5L 5+)H 6LGlu 4+(entry 8,Table 3),and H 2Glu +H 4L 4+)H 6LGlu 4(entry 9Table 3),with percentages of participation that depend on pH.One of the effects of the interaction is to render somewhat more basic the receptor,and somewhat more acidic glutamic acid,facilitating the attraction between op-positely charged partners.A first inspection of Table 3and of the diagrams A,B,and C in Figure 1shows that the interaction strengths differ markedly from one system to another depending on the structural features of the receptors involved.L 4is the receptor that presents the highest capacity for interacting with glutamate throughout all of the pH range explored.It must also be remarked that there are not clear-cut trends in the values of the stepwise constants as a function of the protonation degree of the receptors.This suggests that charge -charge attractions do not play the most(25)(a)Martell,E.;Smith,R.M.Critical Stability Constants ;Plenum:NewYork,1975.(b)Motekaitis,R.J.NIST Critically Selected Stability Constants of Metal Complexes Database ;NIST Standard Reference Database,version 4,1997.Table 1.Protonation Constants of Glutamic Acid and Receptors L 1-L 6Determined in NaCl 0.15mol dm -3at 298.1KreactionGluL 1aL 2aL 3bL 4L 5L 6L +H )L H c 9.574(2)d 9.74(2)8.90(3)9.56(1)9.25(3)9.49(4)9.34(5)L H +H )L H 2 4.165(3)8.86(2)8.27(2)8.939(7)8.38(3)8.11(5)8.13(5)L H 2+H )L H 3 2.18(2)7.96(2) 6.62(3)8.02(1) 6.89(5)7.17(6)7.46(7)L H 3+H )L H 4 6.83(2) 5.85(4)7.63(1) 6.32(5) 6.35(6) 5.97(8)L H 4+H )L H 5 4.57(3) 3.37(4) 2.72(8) 2.84(9) 3.23(9)L H 5+H )L H 6 3.18(3) 2.27(6)∑log K H n L41.135.334.233.634.034.1aTaken from ref 23.b These data were previously cited in a short communication (ref 26).c Charges omitted for clarity.d Values in parentheses are the standard deviations in the last significant figure.Scheme 2.L -Glutamate Acid -BaseBehaviorTable 2.Percentages of the Different Protonated Species at pH 7.4H 1L aH 2LH 3LH 4LL 11186417L 21077130L 3083458L 4083458L 51154323L 6842482aCharges omitted for clarity.A R T I C L E SMiranda et al.826J.AM.CHEM.SOC.9VOL.126,NO.3,2004outstanding role and that other forces contribute very importantly to these processes.26However,in systems such as these,which present overlapping equilibria,it is convenient to use conditional constants because they provide a clearer picture of the selectivity trends.27These constants are defined as the quotient between the overall amounts of complexed species and those of free receptor and substrate at a given pH[eq1].In Figure2are presented the logarithms of the effective constants versus pH for all of the studied systems.Receptors L1and L2with a nonfunctionalized secondary amino group in the side chains display opposite trend from all other receptors. While the stability of the L1and L2adducts tends to increase with pH,the other ligands show a decreasing interaction. Additionally,L1and L2present a close interaction over the entire pH range under study.The tetraaminic macrocycle L3is a better(26)Escartı´,F.;Miranda,C.;Lamarque,L.;Latorre,J.;Garcı´a-Espan˜a,E.;Kumar,M.;Ara´n,V.J.;Navarro,mun.2002,9,936-937.(27)(a)Bianchi,A.;Garcı´a-Espan˜a,c.1999,12,1725-1732.(b)Aguilar,J.A.;Celda,B.;Garcı´a-Espan˜a,E.;Luis,S.V.;Martı´nez,M.;Ramı´rez,J.A.;Soriano,C.;Tejero,B.J.Chem.Soc.,Perkin Trans.22000, 7,1323-1328.Table3.Stability Constants for the Interaction of L1-L6with the Different Protonated Forms of Glutamate(Glu) entry reaction a L1L2L3L4L5L6 1Glu+L)Glu L 3.30(2)b 4.11(1)2HGlu+L)HGlu L 3.65(2) 4.11(1) 3.68(2) 3.38(4) 3Glu+H L)HGlu L 3.89(2) 4.48(1) 3.96(2) 3.57(4) 4HGlu+H L)H2Glu L 3.49(2) 3.89(1) 2.37(4) 3.71(2)5HGlu+H2L)H3Glu L 3.44(2) 3.73(1) 2.34(3) 4.14(2) 2.46(4) 2.61(7) 6HGlu+H3L)H4Glu L 3.33(2) 3.56(2) 2.66(3) 4.65(2) 2.74(3) 2.55(7) 7HGlu+H4L)H5Glu L 3.02(2) 3.26(2) 2.58(3) 4.77(2) 2.87(3) 2.91(5) 8HGlu+H5L)H6Glu L 3.11(3) 3.54(2) 6.76(3) 4.96(3) 4.47(3) 9H2Glu+H4L)H6Glu L 2.54(3) 3.05(2) 3.88(2) 5.35(3) 3.66(4) 3.56(3) 10H2Glu+H5L)H7Glu L 2.61(6) 2.73(4) 5.51(3) 3.57(4) 3.22(8) 11H3Glu+H4L)H7Glu L 4.82(2) 4.12(9)a Charges omitted for clarity.b Values in parentheses are standard deviations in the last significantfigure.Figure1.Distribution diagrams for the systems(A)L1-glutamic acid, (B)L4-glutamic acid,and(C)L5-glutamicacid.Figure2.Representation of the variation of K cond(M-1)for the interaction of glutamic acid with(A)L1and L3,(B)L2,L4,L5,and L6.Initial concentrations of glutamate and receptors are10-3mol dm-3.Kcond)∑[(H i L)‚(H j Glu)]/{∑[H i L]∑[H j Glu]}(1)New1H-Pyrazole-Containing Polyamine Receptors A R T I C L E SJ.AM.CHEM.SOC.9VOL.126,NO.3,2004827receptor at acidic pH,but its interaction markedly decreases on raising the pH.These results strongly suggest the implication of the central nitrogens of the lateral polyamine chains in the stabilization of the adducts.Among the N-functionalized receptors,L4presents the largest interaction with glutamate.Interestingly enough,L5,which differs from L4only in having a phenethyl group instead of a benzyl one,presents much lower stability of its adducts.Since the basicity and thereby the protonation states that L4and L5 present with pH are very close,the reason for the larger stability of the L4adducts could reside on a better spatial disposition for formingπ-cation interactions with the ammonium group of the amino acid.In addition,as already pointed out,L4presents the highest affinity for glutamic acid in a wide pH range,being overcome only by L1and L2at pH values over9.This observation again supports the contribution ofπ-cation inter-actions in the system L4-glutamic because at these pH values the ammonium functionality will start to deprotonate(see Scheme2and Figure1B).Table4gathers the percentages of the species existing in equilibria at pH7.4together with the values of the conditional constant at this pH.In correspondence with Figure1A,1C and Figure S2(Supporting Information),it can be seen that for L1, L2,L5,and L6the prevailing species are[H2L‚HGlu]+and[H3L‚HGlu]2+(protonation degrees3and4,respectively),while for L3the main species are[H3L‚HGlu]+and[H4L‚HGlu]2+ (protonation degrees4and5,respectively).The most effective receptor at this pH would be L4which joins hydrogen bonding, charge-charge,andπ-cation contributions for the stabilization of the adducts.To check the selectivity of this receptor,we have also studied its interaction with L-aspartate,which is a competitor of L-glutamate in the biologic receptors.The conditional constant at pH7.4has a value of3.1logarithmic units for the system Asp-L4.Therefore,the selectivity of L4 for glutamate over aspartate(K cond(L4-glu)/K cond(L4-asp))will be of ca.15.It is interesting to remark that the affinity of L4 for zwiterionic L-glutamate at pH7.4is even larger than that displayed by receptors III and IV(Chart1)with the protected dianion N-acetyl-L-glutamate lacking the zwitterionic charac-teristics.Applying eq1and the stability constants reported in ref17,conditional constants at pH7.4of 3.24and 2.96 logarithmic units can be derived for the systems III-L-Glu and IV-L-Glu,respectively.Molecular Modeling Studies.Molecular mechanics-based methods involving docking studies have been used to study the binding orientations and affinities for the complexation of glutamate by L1-L6receptors.The quality of a computer simulation depends on two factors:accuracy of the force field that describes intra-and intermolecular interactions,and an adequate sampling of the conformational and configuration space of the system.28The additive AMBER force field is appropriate for describing the complexation processes of our compounds,as it is one of the best methods29in reproducing H-bonding and stacking stabiliza-tion energies.The experimental data show that at pH7.4,L1-L6exist in different protonation states.So,a theoretical study of the protonation of these ligands was done,including all of the species shown in5%or more abundance in the potentiometric measurements(Table4).In each case,the more favored positions of protons were calculated for mono-,di-,tri-,and tetraprotonated species.Molecular dynamics studies were performed to find the minimum energy conformations with simulated solvent effects.Molecular modeling studies were carried out using the AMBER30method implemented in the Hyperchem6.0pack-age,31modified by the inclusion of appropriate parameters. Where available,the parameters came from analogous ones used in the literature.32All others were developed following Koll-man33and Hopfinger34procedures.The equilibrium bond length and angle values came from experimental values of reasonable reference compounds.All of the compounds were constructed using standard geometry and standard bond lengths.To develop suitable parameters for NH‚‚‚N hydrogen bonding,ab initio calculations at the STO-3G level35were used to calculate atomic charges compatible with the AMBER force field charges,as they gave excellent results,and,at the same time,this method allows the study of aryl-amine interactions.In all cases,full geometry optimizations with the Polak-Ribiere algorithm were carried out,with no restraints.Ions are separated far away and well solvated in water due to the fact that water has a high dielectric constant and hydrogen bond network.Consequently,there is no need to use counteri-ons36in the modelization studies.In the absence of explicit solvent molecules,a distance-dependent dielectric factor quali-tatively simulates the presence of water,as it takes into account the fact that the intermolecular electrostatic interactions should vanish more rapidly with distance than in the gas phase.The same results can be obtained using a constant dielectric factor greater than1.We have chosen to use a distance-dependent dielectric constant( )4R ij)as this was the method used by Weiner et al.37to develop the AMBER force field.Table8 shows the theoretical differences in protonation energy(∆E p) of mono-,bi-,and triprotonated hexaamine ligands,for the (28)Urban,J.J.;Cronin,C.W.;Roberts,R.R.;Famini,G.R.J.Am.Chem.Soc.1997,119,12292-12299.(29)Hobza,P.;Kabelac,M.;Sponer,J.;Mejzlik,P.;Vondrasek,put.Chem.1997,18,1136-1150.(30)Cornell,W.D.;Cieplak,P.;Bayly,C.I.;Gould,I.R.;Merz,K.M.,Jr.;Ferguson,D.M.;Spelmeyer,D.C.;Fox,T.;Caldwell,J.W.;Kollman,P.A.J.Am.Chem.Soc.1995,117,5179-5197.(31)Hyperchem6.0(Hypercube Inc.).(32)(a)Fox,T.;Scanlan,T.S.;Kollman,P.A.J.Am.Chem.Soc.1997,119,11571-11577.(b)Grootenhuis,P.D.;Kollman,P.A.J.Am.Chem.Soc.1989,111,2152-2158.(c)Moyna,G.;Hernandez,G.;Williams,H.J.;Nachman,R.J.;Scott,put.Sci.1997,37,951-956.(d)Boden,C.D.J.;Patenden,put.-Aided Mol.Des.1999, 13,153-166.(33)/amber.(34)Hopfinger,A.J.;Pearlstein,put.Chem.1984,5,486-499.(35)Glennon,T.M.;Zheng,Y.-J.;Le Grand,S.M.;Shutzberg,B.A.;Merz,K.M.,put.Chem.1994,15,1019-1040.(36)Wang,J.;Kollman,P.A.J.Am.Chem.Soc.1998,120,11106-11114.Table4.Percentages of the Different Protonated Adducts[HGlu‚H j L](j-1)+,Overall Percentages of Complexation,andConditional Constants(K Cond)at pH7.4for the Interaction ofGlutamate(HGlu-)with Receptors L1-L6at Physiological pH[H n L‚HGlu]an)1n)2n)3n)4∑{[H n L‚HGlu]}K cond(M-1)L13272353 2.44×103L2947763 4.12×103L31101324 3.99×102L423737581 2.04×104L51010222 3.51×102L6121224 3.64×102a Charges omitted for clarity.A R T I C L E S Miranda et al. 828J.AM.CHEM.SOC.9VOL.126,NO.3,2004。
An Overview of Recent Progress in the Study of Distributed Multi-agent Coordination
An Overview of Recent Progress in the Study of Distributed Multi-agent CoordinationYongcan Cao,Member,IEEE,Wenwu Yu,Member,IEEE,Wei Ren,Member,IEEE,and Guanrong Chen,Fellow,IEEEAbstract—This article reviews some main results and progress in distributed multi-agent coordination,focusing on papers pub-lished in major control systems and robotics journals since 2006.Distributed coordination of multiple vehicles,including unmanned aerial vehicles,unmanned ground vehicles and un-manned underwater vehicles,has been a very active research subject studied extensively by the systems and control community. The recent results in this area are categorized into several directions,such as consensus,formation control,optimization, and estimation.After the review,a short discussion section is included to summarize the existing research and to propose several promising research directions along with some open problems that are deemed important for further investigations.Index Terms—Distributed coordination,formation control,sen-sor networks,multi-agent systemI.I NTRODUCTIONC ONTROL theory and practice may date back to thebeginning of the last century when Wright Brothers attempted theirfirst testflight in1903.Since then,control theory has gradually gained popularity,receiving more and wider attention especially during the World War II when it was developed and applied tofire-control systems,missile nav-igation and guidance,as well as various electronic automation devices.In the past several decades,modern control theory was further advanced due to the booming of aerospace technology based on large-scale engineering systems.During the rapid and sustained development of the modern control theory,technology for controlling a single vehicle, albeit higher-dimensional and complex,has become relatively mature and has produced many effective tools such as PID control,adaptive control,nonlinear control,intelligent control, This work was supported by the National Science Foundation under CAREER Award ECCS-1213291,the National Natural Science Foundation of China under Grant No.61104145and61120106010,the Natural Science Foundation of Jiangsu Province of China under Grant No.BK2011581,the Research Fund for the Doctoral Program of Higher Education of China under Grant No.20110092120024,the Fundamental Research Funds for the Central Universities of China,and the Hong Kong RGC under GRF Grant CityU1114/11E.The work of Yongcan Cao was supported by a National Research Council Research Associateship Award at AFRL.Y.Cao is with the Control Science Center of Excellence,Air Force Research Laboratory,Wright-Patterson AFB,OH45433,USA.W.Yu is with the Department of Mathematics,Southeast University,Nanjing210096,China and also with the School of Electrical and Computer Engineering,RMIT University,Melbourne VIC3001,Australia.W.Ren is with the Department of Electrical Engineering,University of California,Riverside,CA92521,USA.G.Chen is with the Department of Electronic Engineering,City University of Hong Kong,Hong Kong SAR,China.Copyright(c)2009IEEE.Personal use of this material is permitted. However,permission to use this material for any other purposes must be obtained from the IEEE by sending a request to pubs-permissions@.and robust control methodologies.In the past two decades in particular,control of multiple vehicles has received increas-ing demands spurred by the fact that many benefits can be obtained when a single complicated vehicle is equivalently replaced by multiple yet simpler vehicles.In this endeavor, two approaches are commonly adopted for controlling multiple vehicles:a centralized approach and a distributed approach. The centralized approach is based on the assumption that a central station is available and powerful enough to control a whole group of vehicles.Essentially,the centralized ap-proach is a direct extension of the traditional single-vehicle-based control philosophy and strategy.On the contrary,the distributed approach does not require a central station for control,at the cost of becoming far more complex in structure and organization.Although both approaches are considered practical depending on the situations and conditions of the real applications,the distributed approach is believed more promising due to many inevitable physical constraints such as limited resources and energy,short wireless communication ranges,narrow bandwidths,and large sizes of vehicles to manage and control.Therefore,the focus of this overview is placed on the distributed approach.In distributed control of a group of autonomous vehicles,the main objective typically is to have the whole group of vehicles working in a cooperative fashion throughout a distributed pro-tocol.Here,cooperative refers to a close relationship among all vehicles in the group where information sharing plays a central role.The distributed approach has many advantages in achieving cooperative group performances,especially with low operational costs,less system requirements,high robustness, strong adaptivity,andflexible scalability,therefore has been widely recognized and appreciated.The study of distributed control of multiple vehicles was perhapsfirst motivated by the work in distributed comput-ing[1],management science[2],and statistical physics[3]. In the control systems society,some pioneering works are generally referred to[4],[5],where an asynchronous agree-ment problem was studied for distributed decision-making problems.Thereafter,some consensus algorithms were studied under various information-flow constraints[6]–[10].There are several journal special issues on the related topics published af-ter2006,including the IEEE Transactions on Control Systems Technology(vol.15,no.4,2007),Proceedings of the IEEE (vol.94,no.4,2007),ASME Journal of Dynamic Systems, Measurement,and Control(vol.129,no.5,2007),SIAM Journal of Control and Optimization(vol.48,no.1,2009),and International Journal of Robust and Nonlinear Control(vol.21,no.12,2011).In addition,there are some recent reviewsand progress reports given in the surveys[11]–[15]and thebooks[16]–[23],among others.This article reviews some main results and recent progressin distributed multi-agent coordination,published in majorcontrol systems and robotics journals since2006.Due to space limitations,we refer the readers to[24]for a more completeversion of the same overview.For results before2006,thereaders are referred to[11]–[14].Specifically,this article reviews the recent research resultsin the following directions,which are not independent but actually may have overlapping to some extent:1.Consensus and the like(synchronization,rendezvous).Consensus refers to the group behavior that all theagents asymptotically reach a certain common agreementthrough a local distributed protocol,with or without predefined common speed and orientation.2.Distributed formation and the like(flocking).Distributedformation refers to the group behavior that all the agents form a pre-designed geometrical configuration throughlocal interactions with or without a common reference.3.Distributed optimization.This refers to algorithmic devel-opments for the analysis and optimization of large-scaledistributed systems.4.Distributed estimation and control.This refers to dis-tributed control design based on local estimation aboutthe needed global information.The rest of this article is organized as follows.In Section II,basic notations of graph theory and stochastic matrices are introduced.Sections III,IV,V,and VI describe the recentresearch results and progress in consensus,formation control, optimization,and estimation.Finally,the article is concludedby a short section of discussions with future perspectives.II.P RELIMINARIESA.Graph TheoryFor a system of n connected agents,its network topology can be modeled as a directed graph denoted by G=(V,W),where V={v1,v2,···,v n}and W⊆V×V are,respectively, the set of agents and the set of edges which directionallyconnect the agents together.Specifically,the directed edgedenoted by an ordered pair(v i,v j)means that agent j can access the state information of agent i.Accordingly,agent i is a neighbor of agent j.A directed path is a sequence of directed edges in the form of(v1,v2),(v2,v3),···,with all v i∈V.A directed graph has a directed spanning tree if there exists at least one agent that has a directed path to every other agent.The union of a set of directed graphs with the same setof agents,{G i1,···,G im},is a directed graph with the sameset of agents and its set of edges is given by the union of the edge sets of all the directed graphs G ij,j=1,···,m.A complete directed graph is a directed graph in which each pair of distinct agents is bidirectionally connected by an edge,thus there is a directed path from any agent to any other agent in the network.Two matrices are used to represent the network topology: the adjacency matrix A=[a ij]∈R n×n with a ij>0if (v j,v i)∈W and a ij=0otherwise,and the Laplacian matrix L=[ℓij]∈R n×n withℓii= n j=1a ij andℓij=−a ij,i=j, which is generally asymmetric for directed graphs.B.Stochastic MatricesA nonnegative square matrix is called(row)stochastic matrix if its every row is summed up to one.The product of two stochastic matrices is still a stochastic matrix.A row stochastic matrix P∈R n×n is called indecomposable and aperiodic if lim k→∞P k=1y T for some y∈R n[25],where 1is a vector with all elements being1.III.C ONSENSUSConsider a group of n agents,each with single-integrator kinematics described by˙x i(t)=u i(t),i=1,···,n,(1) where x i(t)and u i(t)are,respectively,the state and the control input of the i th agent.A typical consensus control algorithm is designed asu i(t)=nj=1a ij(t)[x j(t)−x i(t)],(2)where a ij(t)is the(i,j)th entry of the corresponding ad-jacency matrix at time t.The main idea behind(2)is that each agent moves towards the weighted average of the states of its neighbors.Given the switching network pattern due to the continuous motions of the dynamic agents,coupling coefficients a ij(t)in(2),hence the graph topologies,are generally time-varying.It is shown in[9],[10]that consensus is achieved if the underlying directed graph has a directed spanning tree in some jointly fashion in terms of a union of its time-varying graph topologies.The idea behind consensus serves as a fundamental principle for the design of distributed multi-agent coordination algo-rithms.Therefore,investigating consensus has been a main research direction in the study of distributed multi-agent co-ordination.To bridge the gap between the study of consensus algorithms and many physical properties inherited in practical systems,it is necessary and meaningful to study consensus by considering many practical factors,such as actuation,control, communication,computation,and vehicle dynamics,which characterize some important features of practical systems.This is the main motivation to study consensus.In the following part of the section,an overview of the research progress in the study of consensus is given,regarding stochastic network topologies and dynamics,complex dynamical systems,delay effects,and quantization,mainly after2006.Several milestone results prior to2006can be found in[2],[4]–[6],[8]–[10], [26].A.Stochastic Network Topologies and DynamicsIn multi-agent systems,the network topology among all vehicles plays a crucial role in determining consensus.The objective here is to explicitly identify necessary and/or suffi-cient conditions on the network topology such that consensus can be achieved under properly designed algorithms.It is often reasonable to consider the case when the network topology is deterministic under ideal communication chan-nels.Accordingly,main research on the consensus problem was conducted under a deterministicfixed/switching network topology.That is,the adjacency matrix A(t)is deterministic. Some other times,when considering random communication failures,random packet drops,and communication channel instabilities inherited in physical communication channels,it is necessary and important to study consensus problem in the stochastic setting where a network topology evolves according to some random distributions.That is,the adjacency matrix A(t)is stochastically evolving.In the deterministic setting,consensus is said to be achieved if all agents eventually reach agreement on a common state. In the stochastic setting,consensus is said to be achieved almost surely(respectively,in mean-square or in probability)if all agents reach agreement on a common state almost surely (respectively,in mean-square or with probability one).Note that the problem studied in the stochastic setting is slightly different from that studied in the deterministic setting due to the different assumptions in terms of the network topology. Consensus over a stochastic network topology was perhaps first studied in[27],where some sufficient conditions on the network topology were given to guarantee consensus with probability one for systems with single-integrator kinemat-ics(1),where the rate of convergence was also studied.Further results for consensus under a stochastic network topology were reported in[28]–[30],where research effort was conducted for systems with single-integrator kinematics[28],[29]or double-integrator dynamics[30].Consensus for single-integrator kine-matics under stochastic network topology has been exten-sively studied in particular,where some general conditions for almost-surely consensus was derived[29].Loosely speaking, almost-surely consensus for single-integrator kinematics can be achieved,i.e.,x i(t)−x j(t)→0almost surely,if and only if the expectation of the network topology,namely,the network topology associated with expectation E[A(t)],has a directed spanning tree.It is worth noting that the conditions are analogous to that in[9],[10],but in the stochastic setting. In view of the special structure of the closed-loop systems concerning consensus for single-integrator kinematics,basic properties of the stochastic matrices play a crucial role in the convergence analysis of the associated control algorithms. Consensus for double-integrator dynamics was studied in[30], where the switching network topology is assumed to be driven by a Bernoulli process,and it was shown that consensus can be achieved if the union of all the graphs has a directed spanning tree.Apparently,the requirement on the network topology for double-integrator dynamics is a special case of that for single-integrator kinematics due to the difference nature of thefinal states(constantfinal states for single-integrator kinematics and possible dynamicfinal states for double-integrator dynamics) caused by the substantial dynamical difference.It is still an open question as if some general conditions(corresponding to some specific algorithms)can be found for consensus with double-integrator dynamics.In addition to analyzing the conditions on the network topology such that consensus can be achieved,a special type of consensus algorithm,the so-called gossip algorithm[31],[32], has been used to achieve consensus in the stochastic setting. The gossip algorithm can always guarantee consensus almost surely if the available pairwise communication channels satisfy certain conditions(such as a connected graph).The way of network topology switching does not play any role in the consideration of consensus.The current study on consensus over stochastic network topologies has shown some interesting results regarding:(1) consensus algorithm design for various multi-agent systems,(2)conditions of the network topologies on consensus,and(3)effects of the stochastic network topologies on the con-vergence rate.Future research on this topic includes,but not limited to,the following two directions:(1)when the network topology itself is stochastic,how to determine the probability of reaching consensus almost surely?(2)compared with the deterministic network topology,what are the advantages and disadvantages of the stochastic network topology,regarding such as robustness and convergence rate?As is well known,disturbances and uncertainties often exist in networked systems,for example,channel noise,commu-nication noise,uncertainties in network parameters,etc.In addition to the stochastic network topologies discussed above, the effect of stochastic disturbances[33],[34]and uncertain-ties[35]on the consensus problem also needs investigation. Study has been mainly devoted to analyzing the performance of consensus algorithms subject to disturbances and to present-ing conditions on the uncertainties such that consensus can be achieved.In addition,another interesting direction in dealing with disturbances and uncertainties is to design distributed localfiltering algorithms so as to save energy and improve computational efficiency.Distributed localfiltering algorithms play an important role and are more effective than traditional centralizedfiltering algorithms for multi-agent systems.For example,in[36]–[38]some distributed Kalmanfilters are designed to implement data fusion.In[39],by analyzing consensus and pinning control in synchronization of complex networks,distributed consensusfiltering in sensor networks is addressed.Recently,Kalmanfiltering over a packet-dropping network is designed through a probabilistic approach[40]. Today,it remains a challenging problem to incorporate both dynamics of consensus and probabilistic(Kalman)filtering into a unified framework.plex Dynamical SystemsSince consensus is concerned with the behavior of a group of vehicles,it is natural to consider the system dynamics for practical vehicles in the study of the consensus problem. Although the study of consensus under various system dynam-ics is due to the existence of complex dynamics in practical systems,it is also interesting to observe that system dynamics play an important role in determining thefinal consensus state.For instance,the well-studied consensus of multi-agent systems with single-integrator kinematics often converges to a constantfinal value instead.However,consensus for double-integrator dynamics might admit a dynamicfinal value(i.e.,a time function).These important issues motivate the study of consensus under various system dynamics.As a direct extension of the study of the consensus prob-lem for systems with simple dynamics,for example,with single-integrator kinematics or double-integrator dynamics, consensus with general linear dynamics was also studied recently[41]–[43],where research is mainly devoted tofinding feedback control laws such that consensus(in terms of the output states)can be achieved for general linear systems˙x i=Ax i+Bu i,y i=Cx i,(3) where A,B,and C are constant matrices with compatible sizes.Apparently,the well-studied single-integrator kinematics and double-integrator dynamics are special cases of(3)for properly choosing A,B,and C.As a further extension,consensus for complex systems has also been extensively studied.Here,the term consensus for complex systems is used for the study of consensus problem when the system dynamics are nonlinear[44]–[48]or with nonlinear consensus algorithms[49],[50].Examples of the nonlinear system dynamics include:•Nonlinear oscillators[45].The dynamics are often as-sumed to be governed by the Kuramoto equation˙θi=ωi+Kstability.A well-studied consensus algorithm for(1)is given in(2),where it is now assumed that time delay exists.Two types of time delays,communication delay and input delay, have been considered in the munication delay accounts for the time for transmitting information from origin to destination.More precisely,if it takes time T ij for agent i to receive information from agent j,the closed-loop system of(1)using(2)under afixed network topology becomes˙x i(t)=nj=1a ij(t)[x j(t−T ij)−x i(t)].(7)An interpretation of(7)is that at time t,agent i receives information from agent j and uses data x j(t−T ij)instead of x j(t)due to the time delay.Note that agent i can get its own information instantly,therefore,input delay can be considered as the summation of computation time and execution time. More precisely,if the input delay for agent i is given by T p i, then the closed-loop system of(1)using(2)becomes˙x i(t)=nj=1a ij(t)[x j(t−T p i)−x i(t−T p i)].(8)Clearly,(7)refers to the case when only communication delay is considered while(8)refers to the case when only input delay is considered.It should be emphasized that both communication delay and input delay might be time-varying and they might co-exist at the same time.In addition to time delay,it is also important to consider packet drops in exchanging state information.Fortunately, consensus with packet drops can be considered as a special case of consensus with time delay,because re-sending packets after they were dropped can be easily done but just having time delay in the data transmission channels.Thus,the main problem involved in consensus with time delay is to study the effects of time delay on the convergence and performance of consensus,referred to as consensusabil-ity[52].Because time delay might affect the system stability,it is important to study under what conditions consensus can still be guaranteed even if time delay exists.In other words,can onefind conditions on the time delay such that consensus can be achieved?For this purpose,the effect of time delay on the consensusability of(1)using(2)was investigated.When there exists only(constant)input delay,a sufficient condition on the time delay to guarantee consensus under afixed undirected interaction graph is presented in[8].Specifically,an upper bound for the time delay is derived under which consensus can be achieved.This is a well-expected result because time delay normally degrades the system performance gradually but will not destroy the system stability unless the time delay is above a certain threshold.Further studies can be found in, e.g.,[53],[54],which demonstrate that for(1)using(2),the communication delay does not affect the consensusability but the input delay does.In a similar manner,consensus with time delay was studied for systems with different dynamics, where the dynamics(1)are replaced by other more complex ones,such as double-integrator dynamics[55],[56],complex networks[57],[58],rigid bodies[59],[60],and general nonlinear dynamics[61].In summary,the existing study of consensus with time delay mainly focuses on analyzing the stability of consensus algo-rithms with time delay for various types of system dynamics, including linear and nonlinear dynamics.Generally speaking, consensus with time delay for systems with nonlinear dynam-ics is more challenging.For most consensus algorithms with time delays,the main research question is to determine an upper bound of the time delay under which time delay does not affect the consensusability.For communication delay,it is possible to achieve consensus under a relatively large time delay threshold.A notable phenomenon in this case is that thefinal consensus state is constant.Considering both linear and nonlinear system dynamics in consensus,the main tools for stability analysis of the closed-loop systems include matrix theory[53],Lyapunov functions[57],frequency-domain ap-proach[54],passivity[58],and the contraction principle[62]. Although consensus with time delay has been studied extensively,it is often assumed that time delay is either constant or random.However,time delay itself might obey its own dynamics,which possibly depend on the communication distance,total computation load and computation capability, etc.Therefore,it is more suitable to represent the time delay as another system variable to be considered in the study of the consensus problem.In addition,it is also important to consider time delay and other physical constraints simultaneously in the study of the consensus problem.D.QuantizationQuantized consensus has been studied recently with motiva-tion from digital signal processing.Here,quantized consensus refers to consensus when the measurements are digital rather than analog therefore the information received by each agent is not continuous and might have been truncated due to digital finite precision constraints.Roughly speaking,for an analog signal s,a typical quantizer with an accuracy parameterδ, also referred to as quantization step size,is described by Q(s)=q(s,δ),where Q(s)is the quantized signal and q(·,·) is the associated quantization function.For instance[63],a quantizer rounding a signal s to its nearest integer can be expressed as Q(s)=n,if s∈[(n−1/2)δ,(n+1/2)δ],n∈Z, where Z denotes the integer set.Note that the types of quantizers might be different for different systems,hence Q(s) may differ for different systems.Due to the truncation of the signals received,consensus is now considered achieved if the maximal state difference is not larger than the accuracy level associated with the whole system.A notable feature for consensus with quantization is that the time to reach consensus is usuallyfinite.That is,it often takes afinite period of time for all agents’states to converge to an accuracy interval.Accordingly,the main research is to investigate the convergence time associated with the proposed consensus algorithm.Quantized consensus was probablyfirst studied in[63], where a quantized gossip algorithm was proposed and its convergence was analyzed.In particular,the bound of theconvergence time for a complete graph was shown to be poly-nomial in the network size.In[64],coding/decoding strate-gies were introduced to the quantized consensus algorithms, where it was shown that the convergence rate depends on the accuracy of the quantization but not the coding/decoding schemes.In[65],quantized consensus was studied via the gossip algorithm,with both lower and upper bounds of the expected convergence time in the worst case derived in terms of the principle submatrices of the Laplacian matrix.Further results regarding quantized consensus were reported in[66]–[68],where the main research was also on the convergence time for various proposed quantized consensus algorithms as well as the quantization effects on the convergence time.It is intuitively reasonable that the convergence time depends on both the quantization level and the network topology.It is then natural to ask if and how the quantization methods affect the convergence time.This is an important measure of the robustness of a quantized consensus algorithm(with respect to the quantization method).Note that it is interesting but also more challenging to study consensus for general linear/nonlinear systems with quantiza-tion.Because the difference between the truncated signal and the original signal is bounded,consensus with quantization can be considered as a special case of one without quantization when there exist bounded disturbances.Therefore,if consensus can be achieved for a group of vehicles in the absence of quantization,it might be intuitively correct to say that the differences among the states of all vehicles will be bounded if the quantization precision is small enough.However,it is still an open question to rigorously describe the quantization effects on consensus with general linear/nonlinear systems.E.RemarksIn summary,the existing research on the consensus problem has covered a number of physical properties for practical systems and control performance analysis.However,the study of the consensus problem covering multiple physical properties and/or control performance analysis has been largely ignored. In other words,two or more problems discussed in the above subsections might need to be taken into consideration simul-taneously when studying the consensus problem.In addition, consensus algorithms normally guarantee the agreement of a team of agents on some common states without taking group formation into consideration.To reflect many practical applications where a group of agents are normally required to form some preferred geometric structure,it is desirable to consider a task-oriented formation control problem for a group of mobile agents,which motivates the study of formation control presented in the next section.IV.F ORMATION C ONTROLCompared with the consensus problem where thefinal states of all agents typically reach a singleton,thefinal states of all agents can be more diversified under the formation control scenario.Indeed,formation control is more desirable in many practical applications such as formationflying,co-operative transportation,sensor networks,as well as combat intelligence,surveillance,and reconnaissance.In addition,theperformance of a team of agents working cooperatively oftenexceeds the simple integration of the performances of all individual agents.For its broad applications and advantages,formation control has been a very active research subject inthe control systems community,where a certain geometric pattern is aimed to form with or without a group reference.More precisely,the main objective of formation control is to coordinate a group of agents such that they can achievesome desired formation so that some tasks can befinished bythe collaboration of the agents.Generally speaking,formation control can be categorized according to the group reference.Formation control without a group reference,called formationproducing,refers to the algorithm design for a group of agents to reach some pre-desired geometric pattern in the absenceof a group reference,which can also be considered as the control objective.Formation control with a group reference,called formation tracking,refers to the same task but followingthe predesignated group reference.Due to the existence of the group reference,formation tracking is usually much morechallenging than formation producing and control algorithmsfor the latter might not be useful for the former.As of today, there are still many open questions in solving the formationtracking problem.The following part of the section reviews and discussesrecent research results and progress in formation control, including formation producing and formation tracking,mainlyaccomplished after2006.Several milestone results prior to 2006can be found in[69]–[71].A.Formation ProducingThe existing work in formation control aims at analyzingthe formation behavior under certain control laws,along with stability analysis.1)Matrix Theory Approach:Due to the nature of multi-agent systems,matrix theory has been frequently used in thestability analysis of their distributed coordination.Note that consensus input to each agent(see e.g.,(2))isessentially a weighted average of the differences between the states of the agent’s neighbors and its own.As an extensionof the consensus algorithms,some coupling matrices wereintroduced here to offset the corresponding control inputs by some angles[72],[73].For example,given(1),the controlinput(2)is revised as u i(t)= n j=1a ij(t)C[x j(t)−x i(t)], where C is a coupling matrix with compatible size.If x i∈R3, then C can be viewed as the3-D rotational matrix.The mainidea behind the revised algorithm is that the original controlinput for reaching consensus is now rotated by some angles. The closed-loop system can be expressed in a vector form, whose stability can be determined by studying the distribution of the eigenvalues of a certain transfer matrix.Main research work was conducted in[72],[73]to analyze the collective motions for systems with single-integrator kinematics and double-integrator dynamics,where the network topology,the damping gain,and C were shown to affect the collective motions.Analogously,the collective motions for a team of nonlinear self-propelling agents were shown to be affected by。
大学高级英语5第一课 Salvation
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• 4. Let me escort you home.
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of与名词属格构成双重属格，它主要用于两种情 与名词属格构成双重属格， 与名词属格构成双重属格 况： 它所修饰的名词之前， 一．它所修饰的名词之前，要有表示数量的限定 词，如：a, three, some, many, no, any, a few 等，以便表达整体中的一部分，如： 以便表达整体中的一部分， He is a friend of my father’s. Have you ever read any poem of William Shakespeare’s? We have already learned a few songs of CelinDion’s. Peter has read three short stories of Mark Twain’s.
WhatisaGeneATwoSidedView
ESSAYWhat is a Gene?A Two Sided ViewA.Bolondi 1•F.Caldarelli 1•F.Di Felice 1•D.Durano 1•G.Germani 1•L.Michetti 1•A.Tramutolo 1•G.Micheli 2•G.Camilloni 1,2,3Received:18July 2016/Accepted:13October 2016/Published online:19October 2016ÓSpringer Science+Business Media New York 2016The Concept of Gene:A Brief HistorySince its inception (Johannsen 1909)the notion of gene has evolved continuously (Keller 2000).In the past century the point of view about genes has been dominated by genetics up to the ‘30s.The great geneticists of that period,such as Sutton,Morgan,Bridges and Muller (Portin 2002),strongly contributed to the birth of that view.According to the studies on the transmission of characters,the gene is regarded as the indivisible unit of inheritance subject to mutations and genetic recombination.Successively,during the ‘40s,the studies performed on Neurospora crassa allowed to link the concept of gene to the synthesis of a given enzyme,yielding the well-known ‘‘one gene—one enzyme’’theory by Beadle and Tatum (1941).This genetic-biochemical conception had its turning point towards a molecular view in 1953,when Watson and Crick solved the basic structure of DNA (Watson and Crick 1953).The association of DNA with the genetic material had been made ten years before by Avery et al.(1944)and had been confirmed by Hershey and Chase (1952).The notion that the physical base of inheritance resides in DNA paved the way to several important findings,such as those of Jacob and Monod (1961),and became widely acceptedover the ‘70s.This led to amend the concept of gene,identifying it with a continuous DNA sequence responsible for the synthesis of a given mRNA and consequently of a polypeptide.The co-linearity involving gene,RNA and protein has been the standard model until the middle of the ‘70s.Then,following the introduction of recombinant DNA technologies and the consequent cascade of new discov-eries,ideas concerning the essence of a gene did no longer fully correlate with experimental data.The concept of gene evolved further as the limits of the previous view became evident in the light of major novel acquisitions:(1)the discovery of repeated genes that do not code for proteins (Davidson and Britten 1973);(2)the discovery of split genes,which also demonstrated the absence of an absolute gene-protein co-linearity and the existence of a surplus of genetic material (Chow et al.1977);(3)the capability of the cell to process RNA not just in a single way but in many different ways through alternative splicing,resulting in different proteins from the same coding sequence (Horowitz et al.1978).Moreover,in the ‘70s transposable elements,DNA sequences able to move within a genome and among genomes (Cohen 1976),were characterized at the molecular level,although their genetic identity had been predicted by the pioneering studies of Barbara McClintock decades before (McClintock 1947).These findings,followed by several others,e.g.the discovery of overlapping genes (Normark et al.1983),revealed an unexpected plasticity of the genome and the gene-protein co-linearity,with its organization able to change only by mutation or DNA recombination,became old-school.More recently the development of sequencing tech-nologies such as next generation sequencing (NGS),which allows quick sequencing of whole genomes (Schuster 2008),allowed to observe that the entire mammalian&G.Camilloni*****************************1Dipartimento di Biologia e Biotecnologie,Sapienza,Universita`di Roma,Piazzale A.Moro 5,00185Rome,Italy 2Istituto di Biologia e Patologia Molecolari,CNR,Piazzale A.Moro 5,00185Rome,Italy3Istituto Pasteur Italia -Fondazione Cenci Bolognetti e Dipartimento di Biologia e Biotecnologie,Sapienza -Universita`di Roma,Piazzale A.Moro 5,00185Rome,Italy Evol Biol (2017)44:1–4DOI 10.1007/s11692-016-9392-5genome is transcribed in a pervasive manner(Jensen et al. 2013).This implies that not only putative coding regions undergo transcription but that almost the entire genome is transcriptionally active and that the boundaries separating genes are not clearly delineated.This challenges the cur-rently dominant concept of gene as a unit delimited by specific initiation and termination points.Moreover,the advent of epigenetics and novel acquisitions on the tridi-mensional structure of DNA and of its supramolecular complexes,provide experimental support to the notion that, in terms of hereditability,information can be associated also to different elements beyond a simple linear array of nucleotides.Present views see a gene as a DNA sequence converted into RNA through transcription.This RNA,in turn,may or may not be translated into protein(s).Thefinal products of transcription and/or translation specify a character sensu stricto.This implies that the function of a given RNA or of a given protein can affect cell physiology at whatever level,both in a structural respect and/or byregulating or controlling other genes.This definition takes account of protein coding genes,non coding RNAs,split genes,alternative splicing,microRNAs and long non coding RNAs.Genotype Versus Phenotype?The term genotype refers to the entire set of genes in a cell, an organism,or an individual.In the diploid complement of an individual a gene for a particular character or trait may be present in two allelic forms.The notion of p henotype,on the other hand,identifies observable physical or biochem-ical features of an organism,as determined by both genetic makeup and environmental influences.Considering these definitions,the genotype is constituted by the DNA sequences representing genes.However,DNA has intrin-sically also a phenotypic nature because most of its bio-chemical features are observable and measurable. According to this view all DNA structures,intended as simple arrays of pentose sugars linked by phosphodiester bonds and carrying nitrogen bases bound by N-glycosidic linkages,represent the phenotypic essence of a gene(we can call this the DNA phenotype to distinguish it from the phenotype at the organism level,Fig.1)while its geno-typic nature resides in the coding potential underlying transcription.In this morpho-functional perspective a gene is envisaged as a DNA tract endowed with phenotype and genotype at the same time(coding regions),while other regions act as pure phenotype(non coding regions).The genotype nature of a gene could not exist without the supporting framework provided by the DNA phenotype.At the organism level the genotype accounts for the observed phenotype(Fig.1).Traditionally,when discussing about characters associ-ated to DNA coding properties,the phenotype nature of the molecule has been disregarded.From an evolutionary standpoint the informationflux that characterizes the pre-sent reality is the result of natural selection processes that allowed tofix defined genetic and morphologic traits in response to the surrounding environment and its variations. In essence,we know what genetic inheritance is all about, i.e.the transmission of the genetic complement of a gen-eration to its offspring.However,DNA has also its physical nature as an ensemble of atoms occupying a given space and leading to the formation of a defined structure.Beyond the informational-genotypic component it is necessary to consider also the structural-phenotypic aspect of DNA. These two natures mutually affect each other and the boundary separating them is often elusive.Banking on these considerations,the concept of gene phenotype inheritance can be introduced,based on the structure of the DNA molecule and on its ability to be conserved and transmitted in all living organisms since3.5billions of years:while the coding essence is related to the environ-ment,mainly through natural selection,and is subject to large variations,the physical reality of DNA as a molecule remains the same during evolution and is common to all living species.The Epigenetic ScenarioSince1942(Waddington1942)it has been proposed that, at least for certain characters,a further layer controlling inheritance exists,acting on top of the genetic level:epi-genetics.The transmission of the functional state(epigene) Fig.1The two faced nature of genes.The DNA phenotype,i.e.the molecular constitution of the DNA and its epigenetic modifications, determines the coding information,i.e.the genotype.Through gene expression the organismal phenotype is obtained.Following outer inputs the latter may,in turn,influence the DNA phenotype.The double faced image refers to the ancient roman myth of Janus bifronsis as important as the function encoded in a given gene. The functional state can be affected by physical modifi-cations of a gene(e.g.methylation)(Schu¨beler2015)or carried by other chromatin components(i.e.modifications of histone tails;nucleosome positioning and/or occupancy) (Kouzarides2007).These modifications may directly depend on the environment(Feil and Fraga2012).Some phenotypic modifications borne by DNA may pass also to offspring,although in minimal part(Blaze and Roth2015). Hence,the genotype can acquire novel informational content from the environment without changing its sequence but simply by modifying its phenotype.In this perspective epigenetics provides a clear link between the genotypic and the phenotypic nature of a gene. In other words,an epigenetic modification can actually affect the functional status of a gene determining its phe-notypic change through the alteration of the chemical structure of the nucleic acid,but at the same time it can also determine a genotypic regulation by promoting or silencing gene expression and/or by acting on the coding properties of the nucleic acid.Some epigenetic modifica-tions are inheritable,as is the case for DNA methylation, which in turn can trigger additional epigenetic alterations. Epigenetic modifications are also able to alter the genotype by modifying the phenotype.An exemplification comes from experiments showing that in rodents the DNA methylation profiles of germ cells may be altered,with consequent strong transgenerational potential,following exposure of individuals to chemical stress conditions dur-ing adult or prenatal life(Pacchierotti and Spano`2015).In general,there is now substantial agreement that environ-mental and stress factors are strictly related to epigenetic modifications affecting gene expression(Roth2013).In essence,epigenetics as transducer of external signals rep-resents an additional variability source,acting as an addi-tional evolutionary driving force together with natural selection and genetic drift(Schrey et al.2012).The Double Faced GeneThe need to account for all currently available experi-mental observations has reshaped the concept of gene, turning an essentially mechanistic unit predominant during the‘70s into a quite abstract,open and generalized entity whose contour appears less defined as compared to the past.The more data are gathered,the greater an abstraction effort is required in order to understand and define the essence of a gene.The boundaries of the object we are investigating(the gene itself)become fuzzy as we move closer.The same happens at the scale of an electron,with its double nature of particle and wave,where measure-ments become probabilistic and not absolute.Can also the essence of the gene be considered double-faced?In this respect genotypic and phenotypic entities of a gene would coexist and mix reciprocally(Fig.1).This harmonizes present knowledge with current definitions and predisposes for remodeling of our thinking as a consequence of future discoveries.This two-sided view of the gene brings its phenotype and genotype domains closer together and allows to combine the genetic and epigenetic aspects in a unique solution,being structural and functional at the same time and simultaneously able to include the different levels in an overlapping unicum.Acknowledgments This work was partially supported by the Istituto Pasteur-Fondazione Cenci Bolognetti(Universita`di Roma La Sapienza)and by the Epigenomics Flagship Project EpiGen(Italian Ministry of Education and Research,National Research Council).Compliance with Ethical StandardsConflict of interest The authors declare that they have no conflict of interest.ReferencesAvery,O.T.,MacLeod,C.M.,&McCarty,M.(1944).Studies on the chemical nature of the substance inducing transformation of pneumococcal types.Induction of transformation by a desoxyri-bonucleic acid fraction isolated from Pneumococcus type III.Journal of Experimental Medicine,79,137–158.Beadle,G.W.,&Tatum,E.L.(1941).Genetic control of biochemical reactions in Neurospora.Proceedings of the National Academy of Science USA,27,499–506.Blaze,J.,&Roth,T.L.(2015).Evidence from clinical and animal model studies of the long-term and transgenerational impact of stress on DNA methylation.Seminars in Cell&Developmental Biology,43,76–84.Chow,L.T.,Gelinas,R.E.,Broker,T.R.,&Roberts,R.J.(1977).An amazing sequence arrangement at the50ends of adenovirus2 messenger RNA.Cell,12,1–8.Cohen,S.N.(1976).Transposable genetic elements and plasmid evolution.Nature,263,731–738.Davidson,E.H.,&Britten,R.J.(1973).Organization,transcription, and regulation in the animal genome.Quarterly Review of Biology,48,565–613.Feil,R.,&Fraga,M.F.(2012).Epigenetics and the environment: Emerging patterns and implications.Nature Reviews Genetics, 13,97–109.Hershey,A.D.,&Chase,M.(1952).Independent functions of viral protein and nucleic acid in growth of bacteriophage.Journal of General Physiology,36,39–56.Horowitz,M.,Bratosin,S.,&Aloni,Y.(1978).Polyoma infected cells contain at least three spliced late RNAs.Nucleic Acids Research,5,4663–4675.Jacob,F.,&Monod,J.(1961).Molecular and biological character-ization of messenger RNA.Journal of Molecular Biology,3, 318–356.Jensen,T.H.,Jacquier,A.,&Libri,D.(2013).Dealing with pervasive transcription.Molecular Cell,52,473–484.Johannsen,W.(1909).Elemente der exakten erblichkeitslehre(pp.143–144).Gustav Fischer:Jena.Keller, E. F.(2000).The century of the gene.Cambridge,MA: Harvard University Press.Kouzarides,T.(2007).Chromatin modifications and their function.Cell,128,693–705.McClintock,B.(1947).Cytogenetic studies of maize and Neurospora.Carnegie Institute Washington Yearbook,46,146–152. Normark,S.,Bergstro¨m,S.,Edlund,T.,Grundstro¨m,T.,Jaurin,B., Lindberg,F.P.,et al.(1983).Overlapping genes.Annual Review of Genetics,17,499–525.Pacchierotti,F.,&Spano`,M.(2015).Environmental impact on DNA methylation in the germline:State of the art and gaps of knowledge.BioMed Research International,2015,Article ID 123484.Portin,P.(2002).Historical development of the concept of the gene.Journal of Medicine and Philosophy,27,257–286.Roth,T.L.(2013).Epigenetic mechanisms in the development of behavior:Advances,challenges,and future promises of a new field.Development and Psychopathology,25,1279–1291. Schrey,A.W.,Coon,C.A.,Grispo,M.T.,Awad,M.,Imboma,T., McCoy,E.D.,et al.(2012).Epigenetic variation may compen-sate for decreased genetic variation with introductions:A case study using house sparrows(Passer domesticus)on two conti-nents.Genetics Research International,2012,article ID979751. Schu¨beler,D.(2015).Function and information content of DNA methylation.Nature,517,321–326.Schuster,S. C.(2008).Next-generation sequencing transforms today’s biology.Nature Methods,5,16–18.Waddington,C.H.(1942).The epigenotype.Endeavor,1,18–20. Watson,J. D.,&Crick, F.H. C.(1953).A structure for deoxyribonucleic acid.Nature,171,737–738.。
下面大厅里有一个邮箱-里面从来没有过邮件
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I’m learning Japanese, but I still can’t speak it
pinroapneyrlyc.ompany 与任何人在一起 in sb’s company =in company with sb. 和某人一道 e.g. I refused to go further in their company.
break out in tears =break/burst into tears break out in a cold swea=t burst out crying.
break out, break away from, break down, break up (with sb) break in, break into+ a place, break through
4. 开支比计划旳要多。
Expenses had been greater than she had calculated.
①at great/ considerable/ vast expense
花费很大；代价很高 Conference rooms were equipped at great expense. ②at the expense of sb / sth. 以…作为代价 He finished the job at the expense of his health. ③at one’s / one’s (own) expense. 由某人支付 The luxury office building was built at the taxpayers’ expense. ④Travel/medical/living expenses …开支
基于图卷积神经网络的多视角聚类
2021575随着信息技术的飞速发展以及互联网应用的日益丰富，可用数据规模越来越大，数据的表现形式也越来越多样。
例如，网页可以由网页中出现的图片、文字以及超级链接进行表达，又比如文本可以由词频、词向量等多种描述算子进行刻画。
这种描述相同语义的不同特征表达称之为多视角数据。
一般来说，多视角数据描述相同的语义又相互补充，表现为互补与一致特性。
多视角聚类通过挖掘上述特性获得了相比于单视角聚类的有效性能提升，并在数据挖掘、模式识别、信息检索等领域产生广泛的应用[1]。
近些年来，研究者提出了大量的多视角聚类算法并取得了优异的聚类性能。
一般来说，典型多视角聚类算法包含亲和矩阵/图学习算法[2]、子空间学习算法[3]、协同训练算法[4]以及后融合算法[5]。
例如，Chaudhuri等人[6]采用典型相关分析算法实现两视角数据最大相关性挖掘。
Kumar等人[7]基于谱分解技术提出学习不同视角相似或一致的子空间嵌入，进而实现多视角嵌入学习。
Zhao等人[8]引入层次学习思想，提出多视角深度矩阵分基于图卷积神经网络的多视角聚类李勇振1，2，廖湖声11.北京工业大学信息学部，北京1001242.北京建筑大学电气与信息工程学院，北京100044摘要：针对多视角数据间互补与一致特性难以刻画问题，提出一种基于图卷积神经网络的多视角聚类方法。
通过对样本不同视角间相同邻接子图基于图卷积神经网络学习到的表达进行约束，有效挖掘了多视角数据间的一致特性。
通过共享图卷积神经网络参数、学习不同视角完整邻接图嵌入表达并串接得到多视角表达，有效挖掘了多视角数据间的互补特性。
对上述多视角表达增加相对熵约束，使得最终学习到的多视角表达得以提升并符合聚类特性。
在五个数据集上均取得了最好的聚类效果，说明所提出的基于图卷积神经网络的聚类方法可以有效挖掘视角间互补与一致特性并提升聚类性能。
关键词：多视角聚类；图卷积神经网络；相对熵文献标志码：A中图分类号：TP18doi：10.3778/j.issn.1002-8331.2010-0274Multi-view Clustering via Graph Convolutional Neural NetworkLI Yongzhen1，2,LIAO Husheng1rmation Department,Beijing University of Technology,Beijing100124,China2.School of Electrical and Information Engineering,Beijing University of Civil Engineering and Architecture,Beijing100044,ChinaAbstract：Aiming at discovering complementarity and consistency among multi-view data,a multi-view clustering based on Graph Convolutional neural Network（GCN）is proposed.By adding pairwise constraints on embeddings learned via the GCN on common sub-graphs of multiple views,consistency can be effectively measured.Through sharing the parameters of GCN,generating embeddings of each view based on their complete graphs,and concatenating those embeddings for multi-view embedding,complementarity will be explored.Besides,a Kullback-Leibler（KL）divergence based objective is designed to constrain the above embedding,leading to clustering oriented embedding learned.Experiments are conducted on five widely used datasets,achieving best clustering results,which clarifies the effectiveness of the method for exploring complementarity and consistency among multi-view data.Key words：multi-view clustering;graph convolutional neural network;Kullback-Leibler divergence基金项目：北京建筑大学优秀主讲教师培育计划（21082717046）；北京建筑大学基金（00331615029）。
山东省烟台市第四中学九年级上第一学期期中考试英语模拟试题(图片版)(含答案).docx
山东省201R-2019丸车织所中试芯一、所力泌试《•共15八.更共计15分〉听力测流分R 邹分，共20小签 粮甚日，谄片籽答关隽&沐卷上.录言内容结束后, 将所选笞案转涂;I .答祯卡上.(一)听句于・走择勺句子内春州对应的图片.母个包亍该两也(二)听务丈・抿握短文内容月折卜刊句了证误.三由的用“A”表示.不正供的月W”很 示.短义枝西虬 斤尽如，你们有20秒曾的时勺.页设F 列勺子.11.The peldo$ wan the soldie?s. 12.In 190& Gcrnwny started a pro 事am to teach docs to be guides. 13.Ckvcr and lit dogs arc 11K best dogs 奴 the job. 14.It takes over 2 years to train a little dog to be a guide dog. 15. Alter Doro came b^ck to the USA. more people knew the guide Jogs.清考生勺找级第四大遂•你们花4 5秒羽豹准备HJ 间. ft. A. On font.H. Hy hike. ('.By taxi. 7. A. Twice u day.D. Once a week. C. Never. 8. A. See a dentistB. (Jet an X-toy.C. Dtiiik more hot waler 9. A. Lucy. R. M«»\- C.Lily10. A. Talldug about a movie. B. Drawing a picture.C. Tallditg. about apicture. 他必湖内权透择虽住答知对谐相何切都读的避・(-)听时话料何愿.二、单项垃空（共15小题，共计15分）选择最住答案•16. —I kxwie Reais （£熊出没｝）is interesting TV drama that children like watching. —Aiid it% also funny dranixA. the; aB. an;aC. iui; anD. an; the17. My wish is to become a scientist when I grow up. What is______________________________________________________Betty?A. yours 11. ycur C. you 1）. yourself1 & "llic gni bag iCTiniukd lhe oldman lhe aid ihys.A. MB.ol*C. fromD. in19. Wow! Your school is so beautiful!Thank xw! It ______ 3t war.A. buildB. builtC. is builtD. wus built20. Muny people slill u<U shark liii soupno scknliliu shniics support il'x hciiUliy lood.A. butB. whileC. althoughD. if21. The group found it hard _____ the job on time.A.finishing 13. to finish C. finished D. finish22.u young cook wunte lo improve whuuldinner.A. whoseB. whereC. whichD. who23.My hnillicr works hjinl HTid is ofioi . 1 li«j?e lie will have moreA.siurucss;B. siuxc洲；successfulC. successful; successD. successful; successful I24.___ knowledge and experience are important to finish the work.A.EitherB. NsilhcrC. BothD. None25,1 hope QiaL you utm more Qic choice und don't kl me down.A. easilyB. wiselyC. loudly D .secretly26.After a long winter vacation, students usually ___ some weight .They looks a bit fatter.A. put on 13. pul up C. put away D. put ulf27.— vxuiliiig 山：speech iiboul "Bdl anil Road" w心Of course! It was a really great inspiration to the world.A. How anB. What anC. HowD. What2& kind tmd hdpliil Io I he puopk urvund us, ami wc will nuiKu 11K world a nicer placu lo live in.A. To beB. BeingC. ReD. Been29.Jack, is there anything eke you want to know about China?Yes, J ain still wondering.A- how is Ch in 收p«pcr cut mackB.how was ihc Groat Wall built in ancicnl linicsC.why do the Chinese people eat rice dumplings at Dragon Boat FestivalD.why the Chinese people like to play the dragon dance30.—My lalhcr says we uon'l go oil ;i picnic Uiis wcdvend.— You \vg looking Ibnviwd io it.A. Enjoy yourselflB. Never mind.C. Don*! woriy.D. What a pity! 忍、机读理期（25小题.共计25分）A）根据河文内容判新句J提正在，正曲的;IFA”表示，不正站的川*1F表示.Weddings （折il.）arc imporKuil in every vounlrx*. and quilc dillciviil Jrom nalion Io nalioii, Irom Mca Io arv:i. ;md Irom lhe past to lhe prcs^nL However, nil people consider weddingi lo be in）port;uil and happ、events.People in lhe western world go to church for their weddings, while some【rihex（讳落）in Afiica hold their wedding in the open araund a canipfice. whh imidi dancing.In China, weddings ditlkreirt from Ihcse alimad. People in lhe conniryside ized Io carry the bride （我姓）in a sedan chair（大花胳）from her parents, house to her new home. In the late 1970s Hie bridegroom might take the bride to their own new house by bicycle or by tractor （拖拉虬）.Now the bride usually prefers a car, hi girt ly deco 顽ed（般黄i）with flowg and a Chinese characrer（汉'？）meaning double hapjiine^. However, a wedding dinner is necessary in the coiunn^ide and lhe city. Rehlive^ and Itienik who are inviud Io the dimi^r usually drink lo the happiness of （he bride and bridegroom.31.People all over the world tliink lhe weddings AK iniprtaut and happy.32.lu Wcrtcm cowitrics the wedding can be held in the open air.33.In china, A sethi） chair was used to cair\ lhe biitle in the coiuilry side.34.'Ilierc were Uirec uays tor die brickjjrooin Io lake the bride in ihc laic 1970s.35.Wc I cam about the rings ibr the married people Ironi the article.R）驱戊如文火容,逃祥最佳笞案》If cars could drive themselves; what would the world be like? Imagine seeing an empty car passing by on ils way Io pick lip its owner, ora cur lull of passengers who:rc raiding. lisl»niiiig lo musiu or cvai sleeping. Bu（ none ol Ihcin arc worried about Ihc road:dicad.Well, all ofthij» could be the ftiture of driving. There arc several companies, including(MogH working on driver 场(先人驾胶的)cars. So far, no Google self-driven car has gotten a traffic ticket, but some of them have been in accidents when other cars hit lhem, Hiese CN arc now slill in the testing stages (阶段),Bui, il'thc tcjls iuv suvccssliil, these clcdrk scli-drivcn cars could be pul into use very soon.Tlie caw already have many features (峙点)allowing them to take over from drivers duringcertain situations. Some features include care being able to park themselves, or slow down when they notice objects close by. They can also control the speed if there are dang«?rous condilioiis.SuicntisU and engineer believe. wiUi (he help ol'wirckss signals (.万税信号＞canwra$ and GPS, wc arc now al a stage where creating a $;db scl 「drkcn car miglu be possible.Ihe coi^e of deadly rood accidents is usually cai’ele 牌 drivers or dangercii ，conditioiu.'Ihe sell^driven car may he able to prevent these. However, some people do not like ihe idea. American lawjvr Whil Dnikc, lor example, dasmT believe these can arc $ule. He thinks Uul lcchnolo»ics con also be mistakes.36, *lhe nuin purpose of the first paragraph to _.A. tell readeis whai selC-dj iven cars look like.C)根拒队文内咨从方椎巾逸出把当的4孺］或饵借填空，住语点完祟迪I 虬钗个逸项 只剧使用一次，葛枢有一顶列知(第一乖切41 TS 小题迁用，第 浙供・1G 50小我 选用)A. Iricndship B, say C, 131k D. asked E. lhe other F. soinvlhingB. tell readen lo keep away Ircm heavy Irallic.C. get readers lo pay allcntion to road salcty I), make readerfi woiida* about wlf-driven car^.37. What does Ihe miderlnied word 'take over in Paragraph 3 mean?A. Direct the way forB. lake the phcc ofC. work belter thanD. make use of38. Cars already have the Ibllowing Matures EXCEPT ________ .A. parking iteelfB. controlling iluelf in (hng^mus siluaiionsC. Mowinjj ilself down near an object I), avnidiiirj car accickiil 100%39. What mighl make the scll-drivcn cars nm salcly according (o the passage?a. c-rcadingb. wireless signalsc. camerasd. GPSA. a, b, cB. a« h.d40. Wh»1. docx die passage mainly A. Advantages ofscU-drh*cn cars C. PossibilitiesofsclPdrivcn carsC. b, c. dD.a.c,d B, Diilcrcnt opinions on scli-drivcn cansD, Google’s nw technology - self-driven carsThere wus u lime when D:<xbic- didn't have a lol Wiend* She vuw a bi( shy nud didn't 41 much. She neverrvully wauled 1。
学习名词所有格时易错的三个点
学习名词所有格时易错的三个点名词所有格是名词中重要内容之一，最近代中考冲刺班时，了解到很多学生都是掌握了所有格基本的用法，对于一些易错的内容还是比较模糊，在实际做题时错误率较高，针对这个问题，我带大家一起学习下。
■双重所有格的用法问题所谓双重所有格就是指将‘s 所有格与of 所有格结合起来一起使用。
如：a friend of my father’s 我父亲的一位朋友that son of Jim’s 吉姆的那个儿子出现双重所有格的情况，主要是因为在一个名词前通常只用一个限定词，例如在son一词之前，我们不能同时使用that和Jim’s两个限定词，即不能说Jim’s that son，而只可说that son of Jim’s。
学习名词所有格时易错的三个点■节日名称中的所有格用单数还是复数有些要用单数，有些要用复数。
区别如下：1. 在Father’s Day（父亲节），Mother’s Day（母亲节），Valentine’s Day（情人节）等节日名称中，用于所有格的名词却一般是用单数——因为，原则上说一个人通常只有一个父亲、一个母亲、一个情人。
如：The children gave nice presents to their father on Father’s Day. 父亲节那天孩子们给父亲送去精致的礼物。
Mother’s Day is a holiday celebrated on the second Sunday in May. 每逢五月的第二个星期日就是母亲节。
Each year on February 14, lovers around the world celebrate Valentine’s Day. 每年的2月14日，世界各地的情侣都会庆祝情人节。
2. 在Teachers’ Day（教师节），Children’s Day（儿童节），Women’s Day（妇女节）等节日名称中，用于所有格的名词一般是用复数——因为teacher, child, woman通常不止一个。
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二．它所修饰的名词之前，如果有指示代词this, that, these, those修饰，那么这一结构可以表达爱憎和褒贬等情感，如 ： Look at this clever child of Mary’s. We have enjoyed these tasty apple pies of Kate’s. Bill hated that pride of Joe’s. Listen! He is singing those dirty songs again!
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5．双重属格与of属格之间有些微妙的区别，即侧重点不 同，如： He is a friend of my father’s. (侧重点是He is one of my father’s friends.) He is a friend of my father. (侧重点是He is friendly to my father.)
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8．own这个词也可以有类似于双重属格的结构，但是意义 与双重属格不同，如： a house of Paul’s own (其意义是a house owned only by Paul.)(不可用of＋反身代 词) 然而 a house of Paul’s的意思是 one of Paul’s houses。
eg.1.He is a friend of my father's. 在这里，a friend of my father's=one of my father's friends. 2.a painting of my colleague's=one of my colleague's paintings.
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1．双重属格的of 属格只能用指人的名词，而且这个名词 必须是确定的对象，即特指，如： a novel of Lu Xun’s this cute boy of Mr Lee’s those broken shoes of Carl’s 2．被双重属格修饰的名词只能为非特指的名词，下例就 错了： the play of Bernard Shaw’s the cotton field of Mr. Brown’s
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6．当中心名词是表示有一定内容的名词portrait, picture, photo, painting, printing, drawing等，而且受双重属格修饰 时，这一结构表示某人所收藏的肖像、图片和照片等，如 ： This is a portrait of Karl Marx’s. Here are three photos of Henry James’s. 但是，这些名词如果受OF 属格修饰时，这一结构表达了 肖像、图片和照片等的内容就是某人 ，如： This is a portrait of Karl Marx. Here are three photos of Henry James.
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3．of 后的名词属格，在有上下文的情况下，可以用名词 性物主代词代替，如： some books of Charles Dickens’s -- some books of his two cups of Lily’s -- two cups of hers 4．双重属格所修饰的名词可以为疑问代词所修饰，如： Which novel of Ernest Hemingway do you like best of all? How many songs of Jackie Chan have you learned so far?
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⑴用于无生命的东西，表示所有关系，如： the end of the road, the top of the shelf ⑵表示动宾关系，如： the defeat of Napoleon(They defeated Napoleon); the sale of the house (Someone sold the house). ⑶表示主谓关系，如： the needs of the sick(The sick needs sth). ⑷表示同位关系，如： The city of New Castle lies at the mouth of the New Castle River. 纽卡斯尔城位于纽卡斯尔河口。
Double Genitive
双重属格
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What is the double genitive？
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what is the features of double genitive
?
what is the usage?
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独立属格可在of-词组中作介词补足成分，带有独立 属格的of-词组又叫做“双重属格”。
一．它所修饰的名词之前，要有表示数量,非确定特指的限 定词，如：a, three, some, many, no, any, a few等，以便表 达整体中的一部分，如 He is a friend of my father’s. Have you ever read any poem of William Shakespeare’s? We have already learned a few songs of CelinDion’s. Peter has read three short stories of Mark Twain’s.