bluuebunny/crossref_metadata_2025 huggingface dataset:
On Changing the Framework of Psychology: Comparative Psychology is What General Psychology Should Be
Authors: Demarest Jack
Published: December 2005

When behaviorism became the dominant force in American psychology, many of the concerns of functionalism, including evolution, adaptation, and ontogenesis, were left behind. Contemporary psychology textbooks and curricula continue to perpetuate this behaviorist framework despite its atheoretical, nonbiological orientation. Even as these concepts begin to work their way back into textbooks and classrooms, they are treated unsystematically as appendages to the traditional behaviorist framework. Comparative psychology, the last bastion of the functionalist viewpoint, can solve this problem, but misconceptions about the field abound. Some of these misconceptions are discussed in this article, and I demonstrate how a comparative psychology course can provide the framework for reorganizing the focus of general psychology and integrating it into a neofunctionalist perspective.
Unnatural Selection: Comment on the “Teaching Comparative Psychology” Symposium
Authors: Candland Douglas K.
Published: December 2005

In this discussion of symposium papers, I examine why comparative psychologists do not consider professional associations of psychology to represent the core of the discipline. I review textbooks in terms of their contribution to comparative psychology and argue that psychology avoids its natural epistemology, that of natural selection and ultimate causality, in preference for the meretricious offerings provided by proximate causation. I also examine why many psychologists consider evolution to be dehumanizing and state three goals for the teaching of comparative psychology:

(a) its reliance on a central epistemological premise, (b) its demonstration of the historical ways in which comparative psychology has changed our views of human behavior, and (c) its duty to compel the student and the public to examine the ethical standing and rights of animals.
Phases of Feminist Re-Vision in the Psychology of Personality
Authors: Torrey Jane W.
Published: December 2005

Recent literature argues that psychology should include the distinctive and often neglected feminist perspective. McIntosh (1983) proposed five interactive phases in the development of a scholarship that incorporates the more recent and subsequent insights from the psychology of women. This article documents McIntosh's sequence of five phases by using pertinent references to the psychology of personality. The article elaborates on Phase III in which investigators study women as inherently different or deviant from men. Teachers of personality psychology should find the article helpful in recognizing other examples of the phases and in familiarizing themselves and their students with this feminist perspective.
Enhancing the Application to Doctoral Professional Programs: Suggestions from a National Survey
Authors: Eddy Bruce , Lloyd Paul J. , Lubin Bernard
Published: December 2005

All professional programs approved by the American Psychological Association (APA) in 1984 (N = 204) were surveyed by mail questionnaire to identify ways that students could enhance their graduate school applications. Overall response rate was 51%, with no responding bias for type, size, or geographical area. Preparations preferred by clinical, counseling, and school psychology programs in descending order were: research experience, visit to the department, computer knowledge and skills, paid human service experience, volunteer human service experience, social science double major, and Psi Chi membership. Counseling and school psychology programs rated a master's degree significantly higher and a double major (psychology and basic science) significantly lower than did the clinical psychology programs.
Thou Shalt Not Ask Questions: An Approach to Teaching Interviewing Skills
Authors: Sommers-Flanagan John , Means John R.
Published: December 2005

This article describes four components of an approach used to teach interviewing skills to first-year graduate students. First, students are told that they should not ask or answer questions during their first two interviews. Second, students evaluate, orally and in writing, their own behavior during the interview. Third, students are provided feedback from several sources regarding their interviewing skills and interpersonal styles. Fourth, effects of the interview on the subjects, and changes in their attitudes toward psychotherapy, are evaluated because subjects are acquired from an introductory psychology research pool.
An Interview Method for Teaching Adolescent Psychology
Authors: Schwanenflugel Paula J.
Published: December 2005

This article describes an interview method for teaching adolescent psychology. Each student interviews an adolescent on the topic to be covered the following week and writes a report of that interview. The interviews are then used as the basis of classroom discussion. This technique is useful in encouraging students to consider the topic before class and in highlighting the relevance of psychological research for understanding the adolescent.
Writing to Learn While Learning to Write
Authors: Blevins-Knabe Belinda
Published: December 2005

It is argued that, rather than just viewing writing as another skill to teach students, we can use writing to facilitate learning. Different ways that writing can facilitate learning are discussed with reference to how they were applied in a Developmental Psychology course.
Students' Reasons for Changing Answers on Objective Tests
Authors: Shatz Mark A. , Best John B.
Published: December 2005

The circumstances under which answer changing is beneficial or detrimental to test performance were investigated. Undergraduates (N = 65) identified their reasons for changing answers on a 62-item multiple-choice examination. An analysis of the success of answer changing in relation to the reasons offered for changing was completed. Students who reported guessing as their reason for changing answers were not nearly as likely to benefit from their answer changing as were students who reported other reasons. Implications for previous work and test-taking strategies are discussed.
A Radical Poster Session
Authors: Gore Paul A. , Camp Cameron J.
Published: December 2005

In the field of psychology, poster sessions have a history of being an easy and efficient way to present data. Recently, the poster session has been introduced in the classroom. For the last 2 years, we have used a poster session as an integral part of an undergraduate experimental design course. Principles of experimental design are demonstrated when undergraduates design and conduct original experiments using radishes as subjects. Results of these experiments are then presented in a poster session. The benefits of using radishes as subjects are described.
Immediate Feedback, No Return Test Procedure for Introductory Courses
Authors: Friedman Herbert
Published: December 2005

Returning graded answer sheets to a large class is time consuming and delays feedback. These problems are avoided if students mark both the question sheet and the answer sheet for a test that takes half of the class period. Only the answer sheet is collected and students retain the marked question sheets. In the remaining class time, the test items are discussed and the grading scale given. There is no need to return the graded answer sheets at a subsequent class meeting.
Of Windmills and Rope Dancing: The Instructional Value of Narrative Structures
Authors: Fernald L. Dodge
Published: December 2005

Rationale for the instructional value of narrative structures has been emerging steadily in cognitive psychology. The organizational framework that narrative structures offer may be useful for college-level instruction. Introductory textbook chapters were prepared in three modes: traditional, using successive examples to illustrate psychological concepts; intermediate, using a brief sequence of related events; and narrative, using an extended narrative structure. Undergraduates preferred the narrative mode and considered it more enjoyable and more useful for learning.
Learning about Microcomputers and Research
Authors: Peden Blaine F.
Published: December 2005

This article describes (a) student use of the microcomputer before, during, and after an experiment; and (b) the benefits that students derive from learning about microcomputers, in particular, and from conducting research, in general.
Teaching Cross-Cultural Psychology: Providing the Missing Link
Authors: Cushner Kenneth H.
Published: December 2005

Learning about cross-cultural psychology is often difficult because individuals lack pertinent experience. This article describes a new culture-general assimilator that provides knowledge relevant to cross-cultural education. The materials consist of 100 critical incidents introducing 18 culture-general themes, including such concepts as attribution formation, categorization, ingroup-outgroup distinctions, and learning style preferences. Two of the incidents are described and evaluative evidence is presented.
A Course to Develop Competence in Critical Reading of Empirical Research in Psychology
Authors: Anisfeld Moshe
Published: December 2005

A course designed to train students to read original empirical articles independently and critically is described. The course, conducted as a seminar, uses a case-study approach to help students develop data-reading skills and habits. Students learn to concentrate on the Method and Results sections of articles and to guard against unquestioning acceptance of authors' biases. They discover that limited statistical competence need not be an impediment to independent examination of results. Above all, they gain confidence in their ability, even as novices, to read critically the contributions of published researchers.
Preparation of Graduate Students as Classroom Teachers and Supervisors in Applied and Research Settings
Authors: Lumsden Ernest A. , Grosslight Joseph H. , Loveland Edward H. , Williams John E.
Published: December 2005

This article reports a survey of 447 graduate psychology programs in the United States and Canada concerning preparation of graduate students for classroom teaching and supervising the work of others in applied and research settings. Attitudes toward the appropriateness of preparation in each of these three areas of teaching is reported, as well as what is being done in regard to each. Data are grouped by level of degree program in which such training is provided (i.e., doctoral, master's within master's/ doctoral, or masters-only programs). Exemplars are provided as useful models for programs wishing to develop a more systematic approach to preparing their students for classroom teaching. Also, references are cited for guiding the development of training for teaching in the classroom and supervision in applied settings.
Mentoring Women in Academia
Authors: Knox Pamela L. , McGovern Thomas V.
Published: December 2005

We investigated faculty and graduate students' judgments about mentoring women in academia. Overall ratings of important characteristics of mentors were similar to those reported in empirical and descriptive literature. Differences in the women's ratings were not related to demographic characteristics. However, women who were seeking mentors, had mentors, or had been mentors for others, did have different evaluations of this relationship.
A Job Analysis Exercise for an Undergraduate Industrial Psychology Class
Authors: Kottke Janet L.
Published: December 2005

A project requiring undergraduate students to do a job analysis is described. Students prepare job analyses and use them to develop other personnel procedures. Feedback from students has been positive. Recommendations for instructors are provided.
Discussion Topics for Developmental Psychology
Authors: Bryan Anne J.
Published: December 2005

Seven discussion topics for developmental psychology are presented. The topics focus on problems that students might encounter in their lives and are intended to promote application of course material. Students enrolled in a large developmental psychology class gave favorable ratings to the use of this technique.
The Autokinetic Projective Test: A Cautionary Note
Authors: Lovelace Eugene
Published: December 2005

Textbook discussions of the autokinetic effect often mention that this illusory movement is susceptible to suggestion. Several recently published perception texts have presented the autokinetic effect as a potential projective technique, because it is claimed that the light will write out words if the observer expects it to. The accounts in these textbooks are misleading; in a study we conducted, as well as in the original study cited by the texts, the modal event across a series of trials was a failure to see the suggested “writing” movement.
Computer Simulation of the Neuronal Action Potential
Authors: Solomon Paul R. , Cooper Scott , Pomerleau Dean
Published: December 2005

A series of computer simulations of the neuronal resting and action potentials are described. These programs are designed to allow the user to observe the movement of ions across a neuronal membrane during: (a) an action potential, (b) a subthreshold excitatory postsynaptic potential (EPSP), (c) an inhibitory postsynaptic potential, and (d) a suprathreshold EPSP in the presence of the sodium channel blocker tetrodotoxin (TTX).
Faculty Awareness of Textbook Prices
Authors: Sommer Robert , Estabrook Marina , Horobin Karen
Published: December 2005

Considerable variation exists in textbook prices, and this variation is not correlated with book quality as judged by instructors. Community college faculty are more price conscious and more accurate in estimating prices than are university faculty. Most faculty interviewed believe that publishers are not making significant efforts to compete in the area of price, and increased faculty access to price information would lower textbook prices. Recommendations are made for increasing price awareness and knowledge among faculty.
Teaching the Ethical Principles of Psychology
Authors: McGovern Thomas V.
Published: December 2005

Despite an increasing emphasis on ethical issues in recent textbooks and journal articles, teaching the graduate course in ethics and psychology has received almost no attention. This article describes my rationale, method, and evaluations for such a course. Broader issues, such as liberal arts versus specific, discipline-oriented outcomes for graduate courses and the teacher as scientist-practitioner, are also discussed in relation to my experience with teaching ethics.
Teaching Psychology in American and British Universities: Some Personal Impressions
Authors: Remington Bob , Green Patrick
Published: December 2005

On the basis of our experience as British psychologists who have taught in both the United States and the United Kingdom, we make comparisons between the teaching of psychology in British and American universities. We discuss similarities and differences in course structure, curriculum, teaching methods, and evaluation procedures, and we suggest ways in which each system could benefit from some of the other's practices.
Could Charles Darwin Teach Psychology in the 1980s?
Authors: Rigby Marilyn K.
Published: December 2005

Despite the unlikelihood of Charles Darwin teaching psychology in this decade, implications of his personal and professional history for an academic career in psychology are fantasized. Relationships between his theoretical position and the content of an introductory psychology course he might teach and how he might fare in a contemporary academic environment are sketched in this fictionalized account.
Taking Psych 101: A View from the Back of the Room
Authors: Johnson Linda L.
Published: December 2005

Hoping to refresh my memory on how students might study for a first-year college course, I took introductory psychology. I found that certain study skills, such as identifying main ideas and using the SQ3R system, were of little benefit. Information from a single source, either the textbook or the lectures, was often insufficient for adequate comprehension. With only the vaguest understanding of important concepts, it was possible to perform well on multiple-choice tests. Based on my experience in this course, I offer some suggestions for helping students to learn introductory psychology.
Students' Roles, Rights, and Responsibilities as Research Participants
Authors: Korn James H.
Published: December 2005

The research situation is discussed from the point of view of the student participant. Participants may assume roles, varying in the nature of their compliance, as good, faithful, apprehensive, or bad subjects. The rights and responsibilities of research participants are described, and the role of assertive subject is suggested. Finally, a collaborative model of the research relationship is presented as a means of enhancing the educational benefits of the research experience.
Cause and Experiment in Introductory Psychology: An Analysis of R.S. Woodworth's Textbooks
Authors: Winston Andrew S.
Published: December 2005

This article analyzes the emerging notion of experimental method and its relationship to causality in the various editions of R. S. Woodworth's (1921, 1929, 1934, 1940; Woodward & Marquis, 1947) widely used introductory psychology textbook. Beginning with the 1934 edition, experiment was defined as manipulating an independent variable, while holding all other variables constant, and observing the effects on a dependent variable. By the 1940 edition, Woodworth implied that experiments of this type reveal causes, but other methods of inquiry do not. Woodworth's view of experiment and cause and his use of the terms independent and dependent variables appear to be the prototype for later textbooks. The context and implications of these changes are briefly discussed.
Enriching Child Psychology Courses with a Preschool Journal Option
Authors: Sugar Judith , Livosky Marylin
Published: December 2005

This article describes a preschool journal option for child psychology classes. The option requires students to spend 2 hr each week throughout the term as volunteers at a preschool. Weekly journal entries must integrate lecture and text material with practical experience. Participating students earn extra credit, commensurate with their performance, toward their final course grade. Students' evaluations indicate that the project is enjoyable as well as educational. Furthermore, local preschools are eager to participate in exchange for the volunteers.
The Word Fragment Completion Effect: A Computer-Assisted Classroom Exercise
Authors: Schoen Lawrence M.
Published: December 2005

A computer demonstration of the word fragment completion effect was developed to enhance students' comprehension of an experimental paradigm used in cognitive psychology. The robust word fragment completion effect is used to introduce students to the implicit memory paradigm and to illustrate the advantages inherent in such a procedure. The demonstration is a useful tool for comparing and contrasting experimental procedures; it also provides a starting point for a discussion of multiple memory models.
A Computerized Laboratory for General Psychology
Authors: Goolkasian Paula , Lee Jo Ann
Published: December 2005

A computerized General Psychology Laboratory provides students direct experience with contemporary research in psychology. More than 500 students per semester use the lab, which operates with the help of student assistants. Hardware and software requirements and the physical layout of the laboratory are discussed.
A Rotational Format for Team Teaching Introductory Psychology
Authors: Morlock Henry C. , Gaeddert William P. , McCormick Naomi B. , Merrens Matthew R. , Shaffer Lary C. , Zandi Taher
Published: December 2005

This article describes a method for team teaching introductory psychology in which the instructors rotate from section to section, repeating a series of lectures in their areas of expertise. Evaluations indicated that most students liked the format and that the variations in order of topic coverage from section to section were not related to course grades or approval. We provide several suggestions for departments that may wish to adopt this approach.
Self-Scoring: A Self-Monitoring Procedure
Authors: Light Lee C. , McKeachie Wilbert J. , Lin Yi-Guang
Published: December 2005

Self-scoring is a procedure for encouraging students to self-monitor their performance on classroom achievement tests. In our study, students instructed to predict their score on each test item earned higher scores than did students who were not so instructed.
Oral Application Questions as a Teaching Strategy
Authors: Gurman Ernest B. , Holliman W. Bruce , Camperell Kay
Published: December 2005

This research evaluated effects of asking students to apply principles of learning, presented in a beginning psychology course, on examination scores. Compared to control subjects, treatment subjects performed better on factual questions but not on application questions. We suggest that reviewing numerous examples of application questions helped students to integrate and remember the material better, but did not help them to apply principles to new situations.
Learning Activities for Understanding Aging
Authors: Fried Stephen B.
Published: December 2005

This article describes five learning activities for use in courses on aging. The activities concern knowledge of aging, aging stereotypes, personal feelings about aging, aging as portrayed on birthday cards, and old age as represented on television. These activities may help increase awareness of feelings toward aging.
Evaluation of an Undergraduate Psychology Program: Occupational and Personal Benefits
Authors: Quereshi M. Y.
Published: December 2005

A 30-item questionnaire completed by 272 psychology graduates from Marquette University, between May 1973 and May 1983, provided an updated evaluation of the undergraduate program. This study investigated: (a) differences between male and female graduates, (b) graduates' evaluation of the psychology curriculum and faculty, and (c) occupational benefits of the psychology major for those who pursued graduate work in psychology or professional fields and for those who sought employment with the terminal bachelor's degree. Results of this study are compared with those of other alumni surveys published between 1961 and 1987.
Using Actors as “Clients” for an Interviewing Simulation in an Undergraduate Clinical Psychology Course
Authors: Lane Kristi
Published: December 2005

Undergraduate theatre majors are trained to be clients for the interviewing component of an undergraduate clinical psychology course. The actor creates the character of a client after reading appropriate case studies. The instructor assists by providing feedback, helping to create client history, background, and personality characteristics, and by monitoring the degree of pathology that the actor portrays. The actors add a realistic component to this course.
Subject Emphasis in Textbook Photographs and Journal Reports in Educational Psychology
Authors: Burke Richard R.
Published: December 2005

This article describes the content of photographs in selected educational psychology textbooks, the grade levels of subjects reported in three recent volumes of the Journal of Educational Psychology, and the numbers of studies reported in the Educational Resources Information Center's (ERIC) system under elementary students and secondary students. The results suggest that there is an overemphasis on the elementary-level student and elementary-level classroom setting. Implications are related to student perceptions of the value of educational psychology in secondary settings.
Using Computerized Case Simulations in Undergraduate Psychology Courses
Authors: Lambert Matthew E. , Lenthall Gerard
Published: December 2005

Three computerized case simulations, originally developed for graduate training, were used as adjuncts to undergraduate courses in Abnormal Psychology and Counseling Theories. The simulations reflect problems of agoraphobia, chronic headache pain, and bulimia. In using the simulations, students took a therapist's role and were to assess, diagnose, and treat the simulated clients' problems. Students found the simulation task to be a valuable learning tool, enabling them to test many concepts covered in course material. Conclusions and implications are discussed.
Conditioning the Instructor's Behavior: A Class Project in Psychology of Learning
Authors: Chrisler Joan C.
Published: December 2005

A project in conditioning for a Psychology of Learning class is described. Students work as a group to select a target behavior and implement conditioning procedures using an ABAB design. The instructor serves as the subject of the experiment. Each student describes the experiment in an APA-style paper, which counts for 25% of the course grade. The project is popular with students; their experiments are often successful and fun.
Rating Class Participation: The Prof/Peer Method
Authors: Melvin Kenneth B.
Published: December 2005

To reduce the subjectivity of class participation grades, a method was devised that combined forced-distribution peer ratings with professor grades. In seven seminar courses, correlations between professor and peer ratings ranged from .83 to .90. Course/teacher evaluations were high and the prof/peer technique was generally perceived as a fair way to evaluate participation.
A Reexamination of the Relationship of High School Psychology and Natural Science Courses to Performance in a College Introductory Psychology Class
Authors: Griggs Richard A. , Jackson Sherri L.
Published: December 2005

Controlling for possible confoundings in a recent study (Carstens & Beck, 1986), we found that completing a high school psychology class was not related to performance in a college introductory psychology course but a strong background in high school natural science was related to higher grades in the course, especially in the section dealing with topics closely related to natural science. An explanation in terms of the congruence of the scientific–experimental focus of the natural science courses and the college psychology course is suggested.
Assessing Student Outcomes for Psychology Majors
Authors: Halpern Diane F.
Published: December 2005

Numerous state legislatures, accrediting agencies, and public interest groups now require postsecondary institutions to produce evidence that they are providing a quality education for their students. One quality indicator is a measure of the “value added” to the cognitive development of students by the educational program. This approach emphasizes the educational gains made by students in each academic major and from the general education portion of their degree. Psychology departments are often expected to take the lead in assessing educational outcomes because learning assessments are a natural outgrowth of several fields of concentration in psychology–human learning, adult development, psychometrics, and program evaluation. When outcomes are used to improve psychology curricula or departmental policies, they become a powerful tool for improving teaching and learning.
Student Evaluation of Friedman's Immediate Feedback, No Return Test Procedure for Introductory Psychology
Authors: Smith Randolph A. , Wight Randall
Published: December 2005

Friedman's (1987) immediate feedback, no return test technique was evaluated via student ratings. Students were enthusiastic in their assessment of the technique and believed that it facilitated their learning.
Preparing Undergraduates for Paraprofessional Positions: What, Where, When, and How are Ethical Issues Taught?
Authors: Haemmerlie Frances M. , Matthews Janet R.
Published: December 2005

Many undergraduate faculty members are concerned about what their students do after graduation. Because numerous students enter the work force after completing bachelor's degrees in psychology, individual schools have begun to survey their alumni to obtain a clearer picture of the types of jobs available to them. Although many different jobs have been reported, psychology majors are employed in a variety of human service settings. This article raises questions about undergraduate preparation in ethical issues, discusses appropriate paraprofessional roles, and suggests what should be taught, where and when it might be included in the curriculum, and how it might be covered.
Research Findings in Developmental Psychology: Common Sense Revisited
Authors: Barnett Mark A. , Knust Jill , McMillan Tiffany , Kaufman Jane , Sinisi Christina
Published: December 2005

A total of 415 high school and college students completed the Childhood and Adolescence Research Test (CART), a 90-item true–false exam concerning research findings reported in developmental psychology textbooks. The results suggest that many of the research findings presented in these textbooks, like many of those presented in personality textbooks (Barnett, 1986), may already be known to individuals with limited training in psychology. An important implication of these findings for teachers of developmental psychology is noted.
Interviewing across the Life Span: A Project for an Adult Development Course
Authors: Walton Marsha D.
Published: December 2005

A project for an adult development course is described. The project helps students apply the theory and research they study and develop basic interviewing skills. Students interview individuals from different phases of the life cycle and write a paper discussing their subjects' lives in terms of major developmental psychology concepts. This article describes how the students are prepared for the project and how they are evaluated. Some potential problems are discussed.
High and Low Faculty Evaluations: Descriptions by Students
Authors: Waters Marie , Kemp Eleanor , Pucci Aldo
Published: December 2005

Undergraduate students were asked to describe faculty members to whom they had given their highest and lowest evaluations. Highest rated faculty were described in terms of positive personal/motivational and interpersonal characteristics. Lowest rated faculty were described in terms of classroom behavior. Characteristics of highest evaluated faculty, it is suggested, are not bipolar opposites of characteristics of lowest evaluated faculty.
FAK and Src kinases are required for netrin-induced tyrosine phosphorylation of UNC5
Authors: Li Weiquan , Aurandt Jennifer , Jürgensen Claudia , Rao Yi , Guan Kun-Liang
Published: December 2005

During neuronal development, netrin and its receptors UNC5 and DCC (deleted in colorectal cancer) guide axonal growth cones in navigating to their targets. Netrin also plays important roles in the regulation of cell migration, tissue morphogenesis and tumor growth. Here, we show that netrin induces UNC5 tyrosine phosphorylation and that this effect of netrin is dependent on its co-receptor DCC. UNC5 tyrosine phosphorylation is known to be important for netrin to induce cell migration and axonal repulsion. Src tyrosine kinase activity is required for netrin to stimulate UNC5 tyrosine phosphorylation in neurons and transfected cells. The SH2 domain of Src kinase directly interacts with the cytosolic domain of UNC5 in a tyrosine-phosphorylation-dependent manner. Furthermore, the tyrosine kinase focal adhesion kinase (FAK) is also involved in netrin-induced UNC5 tyrosine phosphorylation. Both Src and FAK can phosphorylate UNC5. Our data suggest a model in which netrin stimulates UNC5 tyrosine phosphorylation and signaling in a manner dependent on the co-receptor DCC, through the recruitment of Src and FAK kinases.
Ubiquitin C-terminal hydrolase L1 regulates the morphology of neural progenitor cells and modulates their differentiation
Authors: Sakurai Mikako , Ayukawa Koichi , Setsuie Rieko , Nishikawa Kaori , Hara Yoko , Ohashi Hiroki , Nishimoto Mika , Abe Toshiaki , Kudo Yoshihisa , Sekiguchi Masayuki , Sato Yae , Aoki Shunsuke , Noda Mami , Wada Keiji
Published: December 2005

Ubiquitin C-terminal hydrolase L1 (UCH-L1) is a component of the ubiquitin system, which has a fundamental role in regulating various biological activities. However, the functional role of the ubiquitin system in neurogenesis is not known. Here we show that UCH-L1 regulates the morphology of neural progenitor cells (NPCs) and mediates neurogenesis. UCH-L1 was expressed in cultured NPCs as well as in embryonic brain. Its expression pattern in the ventricular zone (VZ) changed between embryonic day (E) 14 and E16, which corresponds to the transition from neurogenesis to gliogenesis. At E14, UCH-L1 was highly expressed in the ventricular zone, where neurogenesis actively occurs; whereas its expression was prominent in the cortical plate at E16. UCH-L1 was very weakly detected in the VZ at E16, which corresponds to the start of gliogenesis. In cultured proliferating NPCs, UCH-L1 was co-expressed with nestin, a marker of undifferentiated cells. In differentiating cells, UCH-L1 was highly co-expressed with the early neuronal marker TuJ1. Furthermore, when UCH-L1 was induced in nestin-positive progenitor cells, the number and length of cellular processes of the progenitors decreased, suggesting that the progenitor cells were differentiating. In addition, NPCs derived from gad (UCH-L1-deficient) mice had longer processes compared with controls. The ability of UCH-L1 to regulate the morphology of nestin-positive progenitors was dependent on its binding affinity for ubiquitin but not on hydrolase activity; this result was also confirmed using gad-mouse-derived NPCs. These results suggest that UCH-L1 spatially mediates and enhances neurogenesis in the embryonic brain by regulating progenitor cell morphology.
Single-molecule analysis of cadherin-mediated cell-cell adhesion
Authors: Panorchan Porntula , Thompson Melissa S. , Davis Kelly J. , Tseng Yiider , Konstantopoulos Konstantinos , Wirtz Denis
Published: December 2005

Cadherins are ubiquitous cell surface molecules that are expressed in virtually all solid tissues and localize at sites of cell-cell contact. Cadherins form a large and diverse family of adhesion molecules, which play a crucial role in a multitude of cellular processes, including cell-cell adhesion, motility, and cell sorting in maturing organs and tissues, presumably because of their different binding capacity and specificity. Here, we develop a method that probes the biochemical and biophysical properties of the binding interactions between cadherins expressed on the surface of living cells, at the single-molecule level. Single-molecule force spectroscopy reveals that classical cadherins, N-cadherin and E-cadherin, form bonds that display adhesion specificity, and a pronounced difference in adhesion force and reactive compliance, but not in bond lifetime. Moreover, their potentials of interaction, derived from force-spectroscopy measurements, are qualitatively different when comparing the single-barrier energy potential for the dissociation of an N-cadherin-N-cadherin bond with the double-barrier energy potential for an E-cadherin-E-cadherin bond. Together these results suggest that N-cadherin and E-cadherin molecules form homophilic bonds between juxtaposed cells that have significantly different kinetic and micromechanical properties.
Neural induction promotes large-scale chromatin reorganisation of theMash1locus
Authors: Williams Ruth R. E. , Azuara Véronique , Perry Pascale , Sauer Stephan , Dvorkina Maria , Jørgensen Helle , Roix Jeffery , McQueen Philip , Misteli Tom , Merkenschlager Matthias , Fisher Amanda G.
Published: December 2005

Determining how genes are epigenetically regulated to ensure their correct spatial and temporal expression during development is key to our understanding of cell lineage commitment. Here we examined epigenetic changes at an important proneural regulator gene Mash1 (Ascl1), as embryonic stem (ES) cells commit to the neural lineage. In ES cells where the Mash1 gene is transcriptionally repressed, the locus replicated late in S phase and was preferentially positioned at the nuclear periphery with other late-replicating genes (Neurod, Sprr2a). This peripheral location was coupled with low levels of histone H3K9 acetylation at the Mash1 promoter and enhanced H3K27 methylation but surprisingly location was not affected by removal of the Ezh2/Eed HMTase complex or several other chromatin-silencing candidates (G9a, SuV39h-1, Dnmt-1, Dnmt-3a and Dnmt-3b). Upon neural induction however, Mash1 transcription was upregulated (>100-fold), switched its time of replication from late to early in S phase and relocated towards the interior of the nucleus. This spatial repositioning was selective for neural commitment because Mash1 was peripheral in ES-derived mesoderm and other non-neural cell types. A bidirectional analysis of replication timing across a 2 Mb region flanking the Mash1 locus showed that chromatin changes were focused at Mash1. These results suggest that Mash1 is regulated by changes in chromatin structure and location and implicate the nuclear periphery as an important environment for maintaining the undifferentiated state of ES cells.
Topology of three-way junctions in folded RNAs
Authors: LESCOUTE AURÉLIE , WESTHOF ERIC
Published: December 2005

The three-way junctions contained in X-ray structures of folded RNAs have been compiled and analyzed. Three-way junctions with two helices approximately coaxially stacked can be divided into three main families depending on the relative lengths of the segments linking the three Watson-Crick helices. Each family has topological characteristics with some conservation in the non-Watson-Crick pairs within the linking segments as well as in the types of contacts between the segments and the helices. The most populated family presents tertiary interactions between two helices as well as extensive shallow/minor groove contacts between a linking segment and the third helix. On the basis of the lengths of the linking segments, some guidelines could be deduced for choosing a topology for a three-way junction on the basis of a secondary structure. Examples and prediction bas‘ed on those rules are discussed.
Structural study of the H/ACA snoRNP components Nop10p and the 3′ hairpin of U65 snoRNA
Authors: KHANNA MAY , WU HAIHONG , JOHANSSON CARINA , CAIZERGUES-FERRER MICHÈLE , FEIGON JULI
Published: December 2005

The H/ACA small nucleolar ribonucleoprotein (snoRNP) complexes guide the modification of uridine to pseudouridine at conserved sites in rRNA. The H/ACA snoRNPs each comprise a target-site-specific snoRNA and four core proteins, Nop10p, Nhp2p, Gar1p, and the pseudouridine synthase, Cbf5p, in yeast. The secondary structure of the H/ACA snoRNAs includes two hairpins that each contain a large internal loop (the pseudouridylation pocket), one or both of which are partially complementary to the target RNA(s). We have determined the solution structure of an RNA hairpin derived from the human U65 box H/ACA snoRNA including the pseudouridylation pocket and adjacent stems, providing the first three-dimensional structural information on these H/ACA snoRNAs. We have also determined the structure of Nop10p and investigated its interaction with RNA using NMR spectroscopy. Nop10p contains a structurally well-defined N-terminal region composed of a β-hairpin, and the rest of the protein lacks a globular structure. Chemical shift mapping of the interaction of RNA constructs of U65 box H/ACA 3′ hairpin with Nop10p shows that the β-hairpin binds weakly but specifically to RNA. The unstructured region of Nop10p likely interacts with Cbf5p.
A 16–year Study of the Microgap Between 272 Human Titanium Implants and Their Abutments
Authors: Scarano Antonio , Assenza Bartolomeo , Piattelli Maurizio , Iezzi Giovanna , Leghissa Giulio C. , Quaranta Alessandro , Tortora Pietro , Piattelli Adriano
Published: December 2005

A microgap has been described at the level of the implant-abutment connection. This microgap can be colonized by bacteria, and this fact could have relevance on the remodeling of the peri-implant crestal bone and on the long-term health of the peri-implant tissues. The authors report on 272 implants with screw- or cement-retained abutments retrieved from humans for different causes during a 16-year period. In the implants with screw-retained abutments, a 60-μm microgap was present at the level of implant-abutment connection. In some areas the titanium had sheared off from the surface and from the internal threads. The contact between the threads of the implant and those of the abutment was limited to a few areas. Bacteria were often present in the microgaps between implant and abutment and in the internal portion of the implants. In implants with cement-retained abutments, a 40-μm microgap was found at the level of the implant-abutment connection. No mechanical damage was observed at the level of the implant or of the abutment. All the internal voids were always completely filled by the cement. No bacteria were observed in the internal portion of the implants or at the level of the microgap. The differences in the size of the microgap between the two groups were statistically significant (P < .05). In conclusion, in screw-retained abutments the microgap can be a critical factor for colonization of bacteria, whereas in cement-retained abutments all the internal spaces were filled by cement. In these retrieved implants, the size of the microgap was markedly variable and much larger than that observed in vitro.
Contractual Externalities and Common Agency Equilibria
Authors: Martimort David , Stole Lars
Published: December 2005

This paper characterizes the equilibrium sets of common agency games with direct externalities between principals when they compete with nonlinear prices. Direct externalities arise when the contracting variable of one principal directly affects the other principal's payoff. First, we characterize the set of pure-strategy, symmetric equilibria under complete information of an intrinsic common agency game. This set of equilibria is large because of the presence of price-output offers by the principals that are unchosen by the agent in equilibrium. Equilibria exist in which principals offer out-of-equilibrium price-output choices to the agent and induce aggressive, low-price behavior corresponding to marginal-cost pricing in the extreme case. We then show that this equilibrium set of outputs is robust to the possibility that agent refuses any of the offered contracts; the case of delegated agency. Second, we introduce asymmetric information in order to rationalize existing nonlinear pricing contracts. The introduction of asymmetric information has the effect of restricting the set of equilibrium outputs of the intrinsic common agency game.
Rationalization and Incomplete Information
Authors: Battigalli Pierpaolo , Siniscalchi Marciano
Published: December 2005

We analyze a family of extensive-form solution procedures for games with incomplete information that do not require the specification of an epistemic type space a la Harsanyi, but can accommodate a (commonly known) collection of explicit restrictions D on first-order beliefs. For any fixed D we obtain a solution called D-rationalizability.In static games, D-rationalizability characterizes the set of outcomes (combinations of payoff types and strategies) that may occur in any Bayesian equilibrium model consistent with D; these are precisely the outcomes consistent with common certainty of rationality and of the restrictions D. Hence, our approach to the analysis of incomplete-information games is consistent with Harsanyi's, and it may be viewed as capturing the robust implications of Bayesian equilibrium analysis.In dynamic games, D-rationalizability yields a forward-induction refinement of this set of Bayesian equilibrium outcomes. Focusing on the restriction that first-order beliefs be consistent with a given distribution on terminal nodes, we obtain a refinement of self-confirming equilibrium. In signalling games, this refinement coincides with the Iterated Intuitive Criterion.
Shocks and Business Cycles
Authors: Frankel David M , Burdzy Krzysztof
Published: December 2005

A popular theory of business cycles is that they are driven by animal spirits: shifts in expectations brought on by sunspots. A prominent example is Howitt and McAfee (AER, 1992). We show that this model has a unique equilibrium if there are payoff shocks of any size. This equilibrium still has the desirable property that recessions and expansions can occur without any large exogenous shocks. We give an algorithm for computing the equilibrium and study its comparative statics properties. This work generalizes Burdzy, Frankel, and Pauzner (2000) to the case of endogenous frictions and seasonal and mean-reverting shocks.
Incomplete Contracts. Non-Contractible Quality, and Renegotiation
Authors: Lülfesmann Christoph
Published: December 2005

The paper reconsiders the hold-up problem in long-term bilateral trade with specific investments. In our framework, the parties face several trading opportunities (goods) whose characteristics cannot be described at the start of the relationship. Specifically, there exists an investment responsive `innovative' good, and (at least one) non-responsive `standard' good. In line with Hart and Moore (1988), renegotiation takes place as outside option bargaining. We first establish a first-best outcome for the case where trading the innovation is always efficient. This results contrasts with findings in Segal (1999) and Hart and Moore (1999) who adopt an alternative view of renegotiation. Then, we consider a setting where final trade is not always efficient, and show that a properly chosen at-will contract still implements the first best for a non-empty set of parameterizations. Finally, we show that at-will contracts strictly outperform option or specific-performance contracts.
Upgrading, Degrading, and Intertemporal Price Discrimination
Authors: Lee Gea M
Published: December 2005

The paper studies monopoly pricing of a vertically differentiated durable good in a two-period model. It provides an explanation for seemingly unusual practice of a firm selling a "degraded good," arguing that the presence of Coasian dynamics may lead to the sale of the degraded good that is not less costly to produce than a high-quality good. The main finding is that when the firm can identify previous customers only if they voluntarily reveal their past purchases, it sells the degraded good along with the high-quality good in the first period. When the firm sells an upgrade of the degraded good, the price of the high-quality good cannot be "too low" in the second period, since otherwise the upgrading customers would pretend to be new customers. Thus the firm can enhance first-period sales while mitigating consumers' incentive to wait until the next period.
Competitive Equilibria With Incomplete Markets and Endogenous Bankruptcy
Authors: Sabarwal Tarun
Published: December 2005

This paper constructs a model of an exchange economy in which bankruptcy arises in a manner similar to what we observe. Compared to related models, this model is a more realistic representation of some markets in which intertemporal assets are traded. Using standard and natural assumptions, it is shown that every economy represented by this model has an equilibrium. Therefore, bankruptcy can co-exist with smoothly functioning competitive markets in fairly general economies. Examples highlight some welfare effects of bankruptcy.
Adverse Selection and Insurance Contracting: A Rank-Dependent Utility Analysis
Authors: Ryan Matthew Joseph , Vaithianathan Rhema
Published: December 2005

Stiglitz (1977) established three well-known features of monopoly insurance markets subject to adverse selection: (i) at least one market segment is served, despite the informational asymmetry; (ii) there is always some screening of risk classes; and (iii) efficiency is sacrificed to achieve screening. We modify Stiglitzs model, replacing his expected utility assumption on consumer behavior with a version of Quiggins (1982) rank-dependent utility model that has received strong experimental support. We show that none of the conclusions (i)(iii) is robust to this revision. In particular, asymmetric information need not lead to any loss in efficiency.