bluuebunny/crossref_metadata_2025 huggingface dataset:
Mathematics Acceleration of Highly Talented Students: An Evaluation
Authors: Kolitch Elaine R. , Brody Linda E.
Published: September 2007

The purpose of this study was to investigate the precollege mathematics preparation of students with high mathematical aptitude, most of whom were highly accelerated in mathematics. The nature and extent of mathematics coursework and math-related activities and measures of student achievement during the secondary school years were examined. Students evaluated their precollege mathematics preparation in terms of course availability and difficulty, school cooperation, and overall satisfaction. The typical student took calculus in Grade 9, followed by advanced mathematics coursework studied at a local college or magnet high school. Some students experienced difficulty in locating an appropriately challenging and cohesive course of study after first year calculus while still in high school. Despite students' radical acceleration, achievement in calculus and postcalculus coursework was high. Out-of-school math-related activities were prevalent. Gender differences were found in the degree of acceleration and choice of college major. Recommendations for a suitable precollege math program for this population are offered.
The Identification of Giftedness: A Comparison of White, Hispanic and Black Families
Authors: Scott Marcia S. , Perou Ruth , Urbano Richard , Hogan Anne , Gold Susan
Published: September 2007

A survey was sent to White, Hispanic and Black parents of children in the gifted and talented program of a large urban school district. The results indicated that there were few differences among the three parent groups in either the characteristics that had indicated to them that their child might be gifted, or in the attributes which they believed were current descriptors of their gifted child. Large group differences were present, however, between the White sample and the two minority group samples in the percentage of families who requested an evaluation of their child for possible placement in the gifted and talented program. Fewer of the minority parents made such a request. This factor could contribute to the underrepresentation of minority students in gifted programs.
Contributions of Gifted Education to General Education In a Time of Change
Authors: Tomlinson Carol Ann , Callahan Carolyn M.
Published: September 2007

Educators in the field of gifted education should be involved in the educational dialogue known as the School Reform Movement both because of the need of gifted learners for positive changes in education and because of the potential of the field to contribute to improved education for a wide range of students.

Gifted youngsters, like others, suffer from inadequately trained teachers, test-driven instruction, low-level texts, and curricula which engage neither thought nor interest. They are further at risk in settings which mandate student homogeneity and in which teachers are prone to "teach to the middle."

Further, the field of gifted education, by virtue of its principles and practices, has the opportunity to provide educational leadership in expanding views of intelligence, attention to underserved populations, a broadened view of democracy in education, differentiation and individu alization of instruction, and varied instructional models and strategies.
A Developmental Investigation of the Lives of Gifted Women
Authors: Walker Betty A. , Reis Sally M. , Leonard Janet S.
Published: September 2007

Little research exists on intellectually gifted women in relation to their educational, personal, and career choices. This study explores the internal and external factors affecting educational and occupational choices made by gifted women at various times in their lives. A questionnaire was administered to a sample of intellectually gifted women representing the decades of the 1910s through the 1980s who attended a highly selective school for gifted females. Differences in personality and attitude factors were found across decades of graduation and between homemakers and career-oriented intellectually gifted women.
Sex Differences in the Aptitudes and Talents of Children as Judged by Peers and Teachers
Authors: Gagné Françoys
Published: September 2007

Over 40 different descriptions of aptitudes and talents were distributed among nine experimental peer nomination forms (PNF). These PNFs were administered to two large samples of elementary and junior high school pupils and to their teachers. Sex ratios were computed for each ability among those pupils who emerged as the 10% to 15% ablest in their group as independently judged by their peers and teachers. No less than 60% of the 42 items had a significant overrepresentation of girls (or boys); these ratios exceeded 2:1 in a majority of cases. Boys were judged to be more talented in physical aptitudes and technical talents, and girls were judged to be more talented in arts (especially music) and socioaffective aptitudes. Intercorrelations between data from six different samples showed a very high reproducibility of these sex ratios, regardless of whether the judges were peers or teachers or whether samples came from elementary or junior high schools. Various arguments are presented to demonstrate that these judgments by peers and teachers accurately represent the differential abilities manifested by boys and girls in the school environment.
Education Patterns of Academically Talented Youth
Authors: Barnett Linda Boliek , Durden William G.
Published: September 2007

Students who participated in The Johns Hopkins University Center for Talented Youth Academic Programs are compared to eligible students who did not enroll in CTY courses. The two groups of students, over a 5-year period (1980-1984), were matched on gender and Scholastic Aptitude Test (SAT) scores. The results of a questionnaire completed when the last group had finished high school suggest an education pattem of high academic achievement by both groups, with many students pursuing a rigorous high school program including College Board Advanced Placement courses and college courses outside of school. However, students who participated in CTY academic programs reported taking more advanced courses at an earlier age and enrolling in more college courses while in high school than students who did not attend CTY courses. The education pattern and accompanying achievements, exemplified by both groups, provide a validation for the selection instrument, the SAT.
More from the Water Jars: A Reanalysis of Problem-Solving Performance Among Gifted and Nongifted Children
Authors: Shore Bruce M. , Koller Michaela , Dover Arlene
Published: September 2007

An earlier study of performance on water-jar combination problems concluded that giftedness (defined by superior school performance) is associated with metacognitive strength and flexibility in breaking an induced response set. Breaking sets is useful in bringing new perspectives to problem solving. Water-jar studies traditionally drop children who did not form the set, in this case 40% of the initial sample. The present study reanalyzed the initial data but did not exclude the previously omitted subjects. Gifted subjects who failed to form the set actually made the most errors of any group, and they were more likely not to recognize that they had made these errors. Other children who never formed the set were much like those who did. Therefore, gifted children do not always outperform others on cognitive tasks. There may be motivational reasons for this inferior performance.
Deciding to Differentiate Instruction in Middle School: One School's Journey
Authors: Tomlinson Carol Ann
Published: September 2007

As many schools move toward serving a broad range of students in heterogeneous settings, it is important to assist teachers in developing classrooms responsive to the needs of academically diverse learners. Understanding what impedes and what facilitates appropriately differentiated instruction is essential for educational leaders if schools are to move away from one-size-fits-all teaching and if heterogeneous classrooms are to become viable for "academic outliers" such as gifted, struggling, and special education learners. This case study examines the experience of one middle school confronted with a district mandate for differentiated instruction and presents the factors which impeded or facilitated their movement toward appropriately differentiated classrooms.
The Effects of An Enrichment Program on the Families of Participants: A Multiple-Case Study
Authors: Moon Sidney M.
Published: September 2007

The effects of an enrichment program on the families of participating students were explored in this discovery-oriented, retrospective, multiple-case study. The enrichment program investigated was a pull out program based on the Purdue Three-Stage Model that helped identified gifted and talented elementary children develop creative and critical thinking, problem solving, and independent learning skills (Feldhusen and Kolloff, 1978, 1986). Criterion-based selection procedures were used to select the participants (ten families of high school seniors who had participated in the program for at least three years in elementary school). Data were collected through family interviews, questionnaires, and archival records, and were analyzed by inductive, constanl-comparative procedures (Glaser and Strauss, 1967; Goetz and LeCompte, 1984; Strauss and Corbin, 1990) and by data displays (Miles and Huberman, 1994). The findings suggest that, in most cases, the program had a positive influence on both family relationships and home-school relationships.
Identifying Academic Potential in Students from Under-represented Populations: Is Using the Ravens Progressive Matrices a Good Idea?
Authors: Mills Carol J. , Tissot Sherri L.
Published: September 2007

Increasing concern has been focused on the under-representation of African-American and Hispanic students in programs for the academically talented. The Raven's Progressive Matrices (RPM) has been suggested as a possible instrument to help remedy this situation, although little research has been conducted about its viability in identifying academic potential in minority populations. A sample of low-income minority students was given the Raven's Advanced Progressive Matrices (APM) along with a more traditional measure of academic aptitude (The School and College Ability Test) to compare the ability of each to identify students who might profit from advanced-level coursework. There were differences among ethnic groups in results of both tests, but a significantly higher proportion of minority children scored at a high level on the RPM than on the traditional mcasure. In addition, the RPM does appear to be a useful instrument for identifying academic potential in students with limited English proficiency However, there are still issues and concerns surrounding the use of the APM as the sole instrument for selecting students to participate in special programs stressing high-level academic standards and content. The RPM appears to hold more promise as a general screening instrument, to be used in conjunction with other measures to identify students with academic potential who could profit from special programs designed to enhance their academic skills.
Depression and Suicidal Ideation Among Academically Gifted Adolescents
Authors: Baker Jean A.
Published: September 2007

Depression and suicidal ideation among academically gifted adolescents, exceptionally gifted adolescents, and adolescents average in academic performance were examined. No significant difference were detected among the three groups in level, severity, or nature of distress experienced. Results are discussed in light of the supportive interventions appropriate for high school students and the need for further research with subgroups of gifted students more likely to experience psychological distress.
Using the Purdue Three-Stage Model to Facilitate Local Program Evaluations
Authors: Moon Sidney M.
Published: September 2007

Program evaluations conducted by district staff for the purpose of providing feedback to local decision makers are necessary for program improvement and accountability (Fetterman, 1993) can facilitate the creation of longitudinal data bases on the outcomes of gifted and talented programs. This research and development project was undertaken to design, implement, and evaluate a year-long staff development program to improve the evaluation skills of the participants. The Purdue Three-Stage Model (Feldhusen & Kolloff, 1978; Moon, 1994) was used as the theoretical framework for the training program developed. Results suggest that the self-evaluation training was effective in helping coordinators become more skilled program evaluators. Implications of the project for program evaluation, training of program administrators, and longitudinal research on the outcomes of gifted and talented programs are discussed.
Metacognitive Knowledge of Gifted Children and Nonidentified Children in Early Elementary School
Authors: Schwanenflugel Paula J. , Paige Moore Stevens T. , Carr Martha
Published: September 2007

The study compared the declarative metacognitive knowledge of 22 gifted and 40 general cohort kindergarten and first grade children. Children were given a metacognitive interview questionnaire examining their understanding of variables related to memory and attention. Gifted children were superior to the general cohort for only 18% of the memory and 12% of the attention questions. Collapsing across all the questions, however, the gifted showed significantly higher general metacognitive knowledge. Greater metacognitive knowledge in gifted children emerges by early elementary school, particularly for metacognitive attributions.
Gender Differences in Teacher and Student Perceptions of Gifted Students' Ability and Effort
Authors: Siegle Del , Reis Sally M.
Published: September 2007

This study investigated whether female gifted students viewed the quality and importance of their work, effort, and ability differently than male gifted students. The study also investigated whether teachers perceived male and female students differently with respect to these areas in mathematics, language arts, social studies, and science. The sample included 5,385 fourth through eighth grade students who were identified as gifted and talented by their teachers. Teachers consistently rated females higher than males on effort and the quality of their work. Teachers rated males and females similarly on all abilities except language arts in which they rated females higher. Female students rated their language arts ability higher than males while the males rated their mathematics, science, and social studies abilities higher. The correlation between ratings of students' ability and quality of work and ratings of students' effort and quality of work were significantly different for students and teachers.
Chinese-Australians' Knowledge of Depression and Schizophrenia in the Context of Their Under-Utilization of Mental Health Care: an Analysis of Labelling
Authors: Klimidis Steven , Hsiao Fei-Hsiu , Minas Iraklis Harry
Published: September 2007

Background: Low knowledge of and discrimination regarding mental disorders (MDs) may underpin lower access to mental health care by ethnic minority groups.

Aims: In Chinese-Australians, in relation to schizophrenia and depression, to assess (a) labels attached to MDs, (b) conceptual distinctiveness of MDs, (c) labelling accuracy against an Australian representative sample, (d) how syndrome variations may influence labelling, and (e) effects of exposure to MDs on labelling.

Method: 418 subjects were asked to indicate the labels they would apply to vignettes of depression and schizophrenia and whether they were exposed to these disorders personally or socially.

Results: The sample was broadly representative of the Australian-Chinese community: 51% and 47% `correctly' labelled the vignettes. Depression and schizophrenia labels were consistently discriminated and clustered with different other labels. Labelling accuracy surpassed Australians'. Labelling did not vary substantially between syndromes. Exposure related to increased labelling accuracy for depression.

Conclusions: Accuracy in labelling major forms of MDs does not appear low in Chinese-Australians and seems higher than in the Australian community. MDs were discriminated although syndrome variations were not. Findings dispute that low mental health care access and uptake is due to low recognition and discrimination of MDs in Chinese-Australians.
The Harvard Trauma Questionnaire: Adapting a Cross-Cultural Instrument for Measuring Torture, Trauma and Posttraumatic Stress Disorder in Iraqi Refugees
Authors: Shoeb Marwa , Weinstein Harvey , Mollica Richard
Published: September 2007

Background: Mental health assessments in post-conflict zones have relied heavily on Western psychiatric scales. Yet, a strict dependence on the paradigms of Western psychiatry risks inappropriately prioritizing syndromes, such as PTSD, which, however important, are eclipsed by local concerns.

Material and discussion: In Dearborn, Michigan, home to the largest population of Iraqi refugees in the United States, 60 Iraqi refugee life stories were collected in order to adapt the Harvard Trauma Questionnaire (HTQ) to the Iraqi context.

Conclusion: The methodology described proved to be a useful approach to developing a trauma measure that is culturally grounded in a multi-dimensional model of mental health.
Sensitivity to Costs of Fighting versus Sensitivity to Losing the Conflict
Authors: Filson Darren , Werner Suzanne
Published: September 2007

Nations differ in their tolerance for costs of fighting and in their willingness to make concessions. We use a bargaining model of war to analyze these sensitivities. Incentives created by heightened sensitivity to costs often—but not always—contradict those created by heightened sensitivity to making concessions. The results establish the effects of the two sensitivities on key conflict variables such as the frequency with which nations initiate conflicts, are targeted, engage in long or short wars, or receive favorable or unfavorable settlements. It is often asserted that democratic leaders are more sensitive to costs and conflict outcomes than autocrats. If so, then our model suggests that when the two sensitivities reinforce each other, empirical work will yield robust effects of regime type on conflict variables, but when the two sensitivities counter each other, estimated effects will be more ambiguous unless researchers consider which sensitivity dominates.
Foucault's politics and bellicosity as a matrix for power relations
Authors: Hoffman Marcelo
Published: September 2007

From the early to mid-1970s, Michel Foucault posited that power consists of a relation rather than a substance and that this relation is comprised of unequal forces engaged in a warlike struggle against each other, resulting invariably in the domination of some forces over others. This understanding of power, which he retrospectively dubbed `Nietzsche's hypothesis' and `the model of war', underpinned his well-known analyses of disciplinary power. Yet, Foucault in his Collège de France course from the academic year 1975-6, `Society Must Be Defended', suddenly began to call into question this understanding and his doubts about it did not abate well into the late 1970s. In this article, we suggest that his militant politics in the early 1970s sustained his adherence to the war model and that his more cautious political attitude later in the decade underpinned his suspicions about this model.
Effect of varying nitric oxide release to prevent platelet consumption and preserve platelet function in an in vivo model of extracorporeal circulation
Authors: Skrzypchak Amy M. , Lafayette Nathan G. , Bartlett Robert H. , Zhengrong Zhou  , Frost Megan C. , Meyerhoff Mark E. , Reynolds Melissa M. , Annich Gail M.
Published: September 2007

The gold standard for anticoagulation during extracorporeal circulation (ECC) remains systemic heparinization and the concomitant risk of bleeding in an already critically ill patient could lead to death. Normal endothelium is a unique surface that prevents thrombosis by the release of antiplatelet and antithrombin agents. Nitric oxide (NO) is one of the most potent, reversible antiplatelet agents released from the endothelium. Nitric oxide released from within a polymer matrix has been proven effective for preventing platelet activation and adhesion onto extracorporeal circuits. However, the critical NO release (NO flux) threshold for thrombus prevention during ECC has not yet been determined.1 Using a 4-hour arteriovenous (AV) rabbit model of ECC,2 we sought to find this threshold value for ECC circuits, using an improved NO-releasing coating ( Norel-b ). Four groups of animals were tested at variable NO flux levels. Hourly blood samples were obtained for measurement of arterial blood gases, platelet counts, fibrinogen levels and platelet function (via aggregometry). A custom-built AV circuit was constructed with 36 cm of poly(vinyl)chloride (PVC) tubing, a 14 gauge (GA) angiocatheter for arterial access and a modified 10 French (Fr) thoracic catheter for venous access. The Norel-b coating reduced platelet activation and thrombus formation, and preserved platelet function — in all circuits that exhibited an NO flux of 13.65 × 10— 10 mol·cm—2·min—1. These results were significant when compared with the controls. With the Norel-b coating, the NO flux from the extracorporeal circuit surface can be precisely controlled by the composition of the polymer coating used, and such coatings are shown to prevent platelet consumption and thrombus formation while preserving platelet function in the animal. Perfusion (2007) 22, 193—200.
Development and evaluation of a new questionnaire for rating perceived participation1
Authors: Sandström Marianne , Lundin-Olsson Lillemor
Published: September 2007

Objective : To develop a questionnaire for self-rated perceived participation in various life areas and to evaluate its reliability and validity.

Design : Validation and test—retest study including multiple questionnaire-development steps.

Setting : Neurological rehabilitation centre.

Participants : One hundred and fifteen consecutive patients with progressive neurological diseases on the rehabilitation centre's waiting list were eligible to take part in the study; 85 completed. Twenty-two professionals within neurological rehabilitation also took part.

Main measures : Reproducibility, internal consistency, content validity and clinical utility of the Rating of Perceived Participation (ROPP) questionnaire.

Results : The ROPP questionnaire focuses on (1) patient's perceived participation (22 items selected from categories of the participation domains of the International Classification of Functioning, Disability, and Health), (2) patient's satisfaction with the participation level and the desired support for changing it, and (3) patient's selection of the three domains where improvement is most desired. The reproducibility of the perceived-participation items was moderate to good; (weighted kappa ≥0.70 for all but two items) and for satisfaction, desired support, and selected domains it was good or very good (kappa >0.70 for all but in total three items). Test—retest agreement (intraclass correlation (ICC)(1,1) = 0.97) and internal consistency (Cronbach's α = 0.90) for the total score were high. The content validity and clinical utility were good.

Conclusions : The ROPP questionnaire has sufficient psychometric reliability and validity and promises to be a useful questionnaire in neurological rehabilitation. Further research is needed to establish criterion validity and sensitivity to change.
From Eugenics to Scientometrics
Authors: Godin Benoît
Published: September 2007

In 1906, James McKeen Cattell, editor of Science, published a directory of men of science. American Men of Science was a collection of biographical sketches of thousands of men of science in the USA and was published periodically. It launched, and was used in, the very first systematic quantitative studies on science. Cattell used two concepts for his statistics: productivity, defined as the number of men of science a nation produces, and performance or merit, defined as scientific contributions to research as judged by peers. These are the two dimensions that still define measurement of scientific productivity today: quantity and quality. This paper analyzes the emergence of statistics on science and the very first uses to which they were put. It argues that the measurement of science emerged out of interest in great men, heredity and eugenics, and the contribution of eminent men to civilization. Among these eminent men were men of science, the population of whom was thought to be in decline and insufficiently appreciated and supported. Statistics on men of science thus came to be collected to document the case, and to contribute to the advancement of science and the scientific profession.
The Issues Deserve More Credit
Authors: Marres Noortje
Published: September 2007

This paper explores the `issue-oriented' perspective on public involvement in politics opened up by recent research in Science and Technology Studies (STS). This research proposes that public controversy around techno-scientific issues is dedicated to the articulation of these issues and their eventual accommodation in society. It does not, however, fully answer the question of why issue formation should be appreciated as a crucial dimension of democratic politics. To address this question, I turn to the work of two early 20th-century American pragmatists: John Dewey and Walter Lippmann. In their work on democracy in industrial society, they conceived of public involvement in politics as being occasioned by, and providing a way to settle, controversies that existing institutions were unable to resolve. Moreover, Dewey developed a `socio-ontological' understanding of issues, which suggests that people's involvement in politics is mediated by problems that affect them. Dewey and Lippmann thus provide important argumentative resources for further elaborating the approach to public involvement developed in STS. STS research has also developed a `socio-ontological' approach, as it focuses on the `attachments' that people mobilize (and that mobilize people) in the performance of their concern with public affairs. Such an approach provides an alternative to discursivist analysis of the role of `issue framing' in the involvement of publics in politics.
Knowing Cases
Authors: Sturdy Steve
Published: September 2007

This paper examines the scientific work of the Laboratory of the Royal College of Physicians of Edinburgh from its foundation in 1887 to 1920. It looks in particular at the pivotal role of clinical cases in the work of the Laboratory, using the concept of `triangulation' to analyse how cases served both as objects of scientific knowledge and as sites for articulating and aligning the concerns of medical practitioners and career scientists. It goes on to propose a general model for thinking about the role of cases in scientific knowledge production, based on a rereading of Kuhn as seen through the lens of the sociology of scientific knowledge. It concludes with some general reflections on how this analysis of the work of the Laboratory helps us to rethink the relations between basic and applied medical science in the period before the emergence of modern biomedicine.
β-TrCP1-Mediated Degradation of PERIOD2 Is Essential for Circadian Dynamics
Authors: Reischl Silke , Vanselow Katja , Westermark Pål O. , Thierfelder Nadine , Maier Bert , Herzel Hanspeter , Kramer Achim
Published: September 2007

Regulated degradation of circadian clock proteins is a crucial step for rhythm generation per se but also for establishing a normal circadian period. Here, the authors show that the F-box protein beta-transducin repeat containing protein 1 (β-TrCP1) as part of the E3 ubiquitin ligase complex is an essential component of the mammalian circadian oscillator. Down-regulation of endogenous β-TrCP1 as well as expression of a dominant-negative form both result in lengthening of the circadian period in oscillating fibroblasts. These phenotypes are due to an impaired degradation of PERIOD (PER) proteins, since expression of β-TrCP interaction-deficient PER2 variants—but not wild-type PER2—results in a dramatic stabilization of PER2 protein as well as in the disruption of circadian rhythmicity. Mathematical modeling conceptualizes the authors' findings and suggests that loss of sustained rhythmicity in cells with eliminated β-TrCP-mediated PER2 degradation is due to excessive nuclear repression, a prediction they verified experimentally.
Circadian Response Reduction in Light and Response Restoration in Darkness: A “Skeleton” Light Pulse PRC Study in Mice (Mus musculus)
Authors: Comas M. , Beersma D.G.M. , Spoelstra K. , Daan S.
Published: September 2007

Entrainment may involve responses to dawn, to dusk, and to the light in between these transitions. Previous studies showed that the circadian system responds to only 2 light pulses, one at the beginning and one at the end of the day, in a similar way as to a full photoperiod, as long as the photoperiod is less than approximately 1/2 τ. The authors used a double 1-h light pulse protocol with different intervals of darkness in between (1, 2, 4, 7, 10, and 16 h) to study the phase responses of mice. The phase response curves obtained were compared to full light pulse PRCs of corresponding durations. Up to 6 hours, phase responses induced by double light pulses are virtually the same as by a corresponding full light pulse. The authors made a simple phase-only model to estimate the response reduction due to light exposure and response restoration due to dark exposure of the system. In this model, they assumed a 100% contribution of the first 1-h light pulse and fitted the reduction factor for the second light pulse to yield the best fit to the observations. The results suggest that after 1 h of light followed by less than 4 h of darkness, there is a considerable reduction in response to the second light pulse. Full response restoration requires more than 10 h of darkness. To investigate the influence of the duration of light on the response saturation, the authors performed a second series of experiments where the duration of the 2 light pulses was varied from 4 to 60 min each with a fixed duration of the stimulus (4 h). The response to 2 light pulses saturates when they are between 30 and 60 min long. In conclusion, double pulses replace single full light pulses of a corresponding duration of up to 6 h due to a response reduction during light, combined with response restoration during darkness. By the combined response reduction and response restoration, mice can maintain stable entrainment to the external LD cycle without being continuously exposed to it.
Melanopsin-Dependent Nonvisual Responses: Evidence for Photopigment Bistability In Vivo
Authors: Mure Ludovic S. , Rieux Camille , Hattar Samer , Cooper Howard M.
Published: September 2007

In mammals, nonvisual responses to light have been shown to involve intrinsically photosensitive retinal ganglion cells (ipRGC) that express melanopsin and that are modulated by input from both rods and cones. Recent in vitro evidence suggests that melanopsin possesses dual photosensory and photoisomerase functions, previously thought to be a unique feature of invertebrate rhabdomeric photopigments. In cultured cells that normally do not respond to light, heterologous expression of mammalian melanopsin confers light sensitivity that can be restored by prior stimulation with appropriate wavelengths. Using three different physiological and behavioral assays, we show that this in vitro property translates to in vivo, melanopsin-dependent nonvisual responses. We find that prestimulation with long-wavelength light not only restores but enhances single-unit responses of SCN neurons to 480-nm light, whereas the long-wavelength stimulus alone fails to elicit any response. Recordings in Opn4-/- mice confirm that melanopsin provides the main photosensory input to the SCN, and furthermore, demonstrate that melanopsin is required for response enhancement, because this capacity is abolished in the knockout mouse. The efficiency of the light-enhancement effect depends on wavelength, irradiance, and duration. Prior long-wavelength light exposure also enhances short-wavelength—induced phase shifts of locomotor activity and pupillary constriction, consistent with the expression of a photoisomerase-like function in nonvisual responses to light.
The Fruit Fly Drosophila melanogaster Favors Dim Light and Times Its Activity Peaks to Early Dawn and Late Dusk
Authors: Rieger Dirk , Fraunholz Christina , Popp Jochen , Bichler Dominik , Dittmann Rainer , Helfrich-Förster Charlotte
Published: September 2007

The light preferences of fruit flies were tested by 2 different means. First, flies were allowed to choose between different illuminations, and their favorite resting, grooming, and feeding places were determined with an infrared-sensitive camera. Second, the activity levels of the animals during their main daily activity period were determined photoelectrically (via infrared light beams) under different light intensities. Both methods revealed that the flies prefer dim light. They rested, groomed, and fed preferentially in places with a light intensity between 5 and 10 lux, and they showed the highest activity level when the light intensity during the day was kept at 10 lux. Furthermore, when dawn and dusk were simulated by logarithmically increasing/decreasing the light intensity during a 1.5-h interval, the flies' activity maxima occurred at about 7.5 lux during early dawn and late dusk. The results suggest that fruit flies time their clocks by early dawn and late dusk and avoid bright light during the day.
Sea ice expansion in the Bering Sea during the Neoglacial: evidence from archaeozoology
Authors: Crockford S.J. , Frederick S.G.
Published: September 2007

The Neoglacial was a period of cold that lasted more than 2000 years during the mid-Holocene, from approximately 4700 to 2500 years ago. Although proxy data from a number of sources document the regional onset and duration of cold conditions in the Northern Hemisphere during this period, none have suggested an expansion of sea ice in the Bering Sea. Here we provide new evidence that Neoglacial sea ice expansion in the Bering Sea was substantial enough to have altered the distribution of North Pacific pinnipeds and cetaceans, using prehistoric skeletal remains recovered from an archaeological site on the island of Unalaska in the eastern Aleutians (Amaknak Bridge, occupied from c. 3500—2500 yr BP (radiocarbon years before present, uncalibrated)). Comprehensive archaeozoological analysis of the Amaknak Bridge fauna indicates that sea ice in the Bering Sea must have reached a more southerly position at the height of the Neoglacial and persisted longer than it does today. We infer from this evidence that for most of the Neoglacial period, sea ice must have surrounded the Pribilof Islands until early summer and blocked the Bering Strait until late summer. Such an expansion and seasonal persistence of sea ice would have prevented fur seals from using the Pribilofs as a summer breeding rookery and whales from making summer migrations into arctic waters to feed, as they do today. We suggest this expansion of sea ice in the Bering Sea during the Neoglacial may explain several unresolved phenomena of mammalian distributions, genetic partitioning and extinctions in the North Pacific.
Holocene mass-transport activity and climate in outer Isfjorden, Spitsbergen: marine and subsurface evidence
Authors: Forwick Matthias , Vorren Tore O.
Published: September 2007

The analyses of high-resolution seismic data, swath bathymetry data and sediment cores from the basin Svensksunddjupet in Isfjorden, Spitsbergen, reveal the deposits of repeated slope failures. Most of the slope failures occurred during three periods at c. 9650 cal. BP, 8350—8200 cal. BP and 3000 cal. BP. Suggested factors causing instability of the slopes include earthquake activity resulting from rapid isostatic uplift, excess pore pressure caused by relative sea-level fall and/or the presence of gas as well as climatic changes. Mass-transport deposits at the mouth of an incision at the southern slope of Svensksunddjupet are suggested to mainly relate to runoff from the land-based glacier Vardebreen. The increase of the mass-transport activity may indicate that Vardebreen either formed or increased in size at c. 7000 cal. BP.
16 000 years of vegetation and settlement history from Egelsee (Menzingen, central Switzerland)
Authors: Wehrli Michael , Tinner Willy , Ammann Brigitta
Published: September 2007

Past vegetation dynamics and human impact from the Lateglacial to the present are reconstructed by pollen analysis of a core 12 m long from the raised bog Egelsee, central Switzerland (770 m a.s.l.). The depth—age model of the core is based on 29 AMS 14C dates. The oldest dated macrofossil has an age of 13 080 ± 105 radiocarbon yr BP (15 370 cal. yr BP); extrapolation leads to a basal age of the core of 16 200 cal. yr BP. The biostratigraphy shows a typical vegetation development for Central Europe from open pioneer vegetation to Betula- Pinus forests in the Lateglacial, thermophilous mixed deciduous forests in the early Holocene, then mesophilous Abies-Fagus forests, and finally to the present cultural landscape. The initial population expansion of Abies alba may have coincided with climatic change at c. 8500 cal. yr BP. The mass expansion of Abies alba at 8100 cal. yr BP may have been triggered by the 8.2-ka event and coincided with the empirical limit of Fagus silvatica, indicating initial population expansions. The succession of ecosystems with different plant composition is confirmed by detrended correspondence analysis (DCA): the main changes in the DCA axis 1 and 2 correspond to the transition phases between the different ecosystems. DCA axis 1 has an eigenvalue of λ1 = 0.46 and is significantly correlated ( r = 0.82) to the non-arboreal pollen percentage curve. Rarefaction analysis shows a high pollen diversity in the Lateglacial, lower pollen diversity in the Holocene before human impact, and increasing pollen diversity correlated with increasing human impact. Very little is known about the archaeology of the montane belt in central Switzerland. This study provides new data concerning human impact and settlement history in this area. Human activities are indicated by cereal pollen (earliest Hordeum/Triticum type at 4700 cal. yr BP). Distinct pulses of anthropogenic forest clearances can be observed from the Neolithic period onwards.
Holocene vegetation development in Bela krajina (Slovenia) and the impact of first farmers on the landscape
Authors: Andrič Maja
Published: September 2007

This study examines the variability of the Holocene landscape and the extent of human impact on the vegetation of Bela krajina region (southeastern Slovenia). Pollen and microcharcoal records of two small palaeoecological sites Mlaka and Griblje (G3), located just c. 10 km apart, indicate that human impact, manifested as forest clearance and burning, was significant throughout the Holocene and led to change of forest composition, impoverishment of soils, increased biodiversity and formation of a mosaic landscape with significant differences between the two sites. On both sites the strongest human impact associated with Fagus decline and the appearance of taxa characteristic for meadows, fields and pastures was detected from approximately 6000 cal. yr. BP onwards. However, differences between study sites were significant. At Mlaka, located on predominantly limestone bedrock, the human impact was very intensive and the present-day open landscape was formed by the Mediaeval period at c. 1000 cal. BP. In comparison the landscape around Griblje (on sandy bedrock) remained predominantly forested to the present.
Reconstruction of late-Holocene slope and dry valley sediment dynamics in a Belgian loess environment
Authors: Rommens Tom , Verstraeten Gert , Peeters Iris , Poesen Jean , Govers Gerard , Van Rompaey Anton , Mauz Barbara , Packman Susan , Lang Andreas
Published: September 2007

To unravel the evolution of a dry valley in the Belgian loess area soils and sediments along a slope catena were studied in detail. A 67 m long trench was opened from the upper slope to the centre of the valley bottom. The exposed soils and sediments showed evidence of severe soil erosion and other human disturbances that significantly changed the valley topography. The early-Holocene slope gradient was up to 25%, whereas now it is less than 10%. In the thalweg, a remnant of the early-Holocene soil was found underneath colluvial deposits, which were more than 3 m thick. A chronology for the valley evolution was established based on AMS14C dating of charcoal fragments and optical dating of colluvial sediments. The first sediment deposition occurred in the early Iron Age, with an average sedimentation rate of approximately 3.4 ± 1.3 t/ha per yr. This increased to c. 5.4 ± 2.2 t/ha per yr during the Roman Period and further to 18.0 ± 2.2 t/ha per yr in the Middle Ages. Although sediment accumulation in the valley was substantial, soil-erosion processes were mainly low-magnitude and signs of gullying are absent in the thalweg until the last few centuries.
A palaeolimnological record of diatom-community dynamics and late-Holocene climatic changes from Prescott Island, Nunavut, central Canadian Arctic
Authors: Finkelstein Sarah A. , Gajewski K.
Published: September 2007

Palaeolimnological analyses from Lake PW03, a small, dilute lake on crystalline bedrock on Prescott Island, Nunavut, Canada (73°07′ N, 96°41′ W, 243 m a.s.l.), provide a sensitive record of the impacts of Holocene climatic change on diatom communities. A high-resolution sequence from 3500 cal. BP to present indicates that a significant change in diatom assemblages takes place at 2300 cal. BP, when alkaliphilous fragilarioids and planktonic taxa are replaced by benthic, epiphytic and acidophilous diatoms. These changes coincide with the onset of neoglacial cooling and likely reflect more persistent ice-cover and associated acidification of lake water. Maximum diatom species richness occurs during this period of transition. Dense bryophyte communities in the littoral zone provide habitats to sustain diatom production even under the cooler conditions following 2300 cal. BP. The concentration of diatom valves declines at 500 cal. BP, coincident with cooling at the time of the `Little Ice Age', and minor changes in species composition take place at that time. The sediments deposited over the past 150 years show modest increases in fragilarioids and planktonic diatoms, in response to a longer ice-free season under a warmer climate. Diatom valve production increases significantly in these recent sediments but increases in diversity are relatively small. Diatom diversity, production and the species composition of diatom communities do not change simultaneously in response to climatic changes.
Sedimentary charcoal pattern in a karstic underground lake, Vercors massif, French Alps: implications for palaeo-fire history
Authors: Carcaillet Christopher , Perroux Anne-Sophie , Genries Aurélie , Perrette Yves
Published: September 2007

Knowledge on processes of charcoal transportation is crucial for fire reconstruction based on sedimentary charcoal. Charcoal is susceptible to long-distance transport by water. A lake basin with a large and long catchment area is likely to accumulate charcoal from many fires, not only those produced by fires nearby the lakeshore. Here we test the potential of charcoal transportation by analysing sedimentary charcoal accumulated in an underground lake within a karstic massif. Fires cannot spread around the lake, nor within the karstic massif. Organic materials, including charred particles, are generated several kilometres from the lake on the karstic plateau above. The pattern of sedimentary charcoal shows that the underground lake records continuously produced charcoal by wild fires or human-made biomass burning (slash-and-burn, charcoal kilns) over centuries and millennia, but also stored charcoal from eroded soils. Although the charcoal series shows a certain high variability signal, fire frequency reconstruction cannot be performed owing to chronological uncertainties. The charcoal accumulation corresponds to a more or less regular background input. Such background input is empirically well described in palaeo-fire reconstruction, but was never experimentally displayed. This study provides evidence that the pattern (surface, length, slope, etc.) of catchment areas is crucial for interpreting sedimentary charcoal series. Large catchment areas draining long rivers are not suitable for high-resolution and spatially precise fire reconstructions.
Rates of Holocene chemical weathering, `Little Ice Age' glacial erosion and implications for Schmidt-hammer dating at a glacier—foreland boundary, Fåbergstølsbreen, southern Norway
Authors: Owen Geraint , Matthews John A. , Albert Paul G.
Published: September 2007

Average rates of Holocene chemical weathering and `Little Ice Age' glacial erosion of bedrock are estimated across the glacier—foreland boundary of an outlet glacier of the Jostedalsbreen ice-cap, southern Norway. Estimates are derived from two types of evidence: (1) the heights of quartz veins above adjacent surfaces of granitic or granodioritic gneiss; and (2) Schmidt-hammer R-values of rock hardness. Average and maximum rates of surface lowering of gneiss surfaces by chemical weathering are 1.63 and 3.61 mm/ka, respectively, whereas many quartz veins exhibit negligible weathering after c. 9700 years. `Little Ice Age' glacial erosion rates are at least two orders of magnitude greater than the chemical weathering rates, except in a narrow marginal zone inside, but close to, the `Little Ice Age' limit, where patches of weathered surface survive. Bedrock surfaces outside and well inside the `Little Ice Age' glacier—foreland boundary are shown to have potential for improved calibrated-age dating using R-values, compared with moraine surfaces.
The philosophy of local studies in the interactive age
Authors: Reid Peter H. , Macafee Caroline
Published: September 2007

The authors examine strategic priorities for local studies libraries in the context of the interactive Web. They examine the implications for access, investigations and the needs of different users. The philosophy that has previously guided local studies is articulated as a number of maxims, taking into account also social inclusion and lifelong learning. These maxims are then re-assessed and added to in the light of issues such as the acquisition of digital media objects, mass amateurisation, profiling remote users and balancing their needs with those of local taxpayers, digital service provision and creating and maintaining an effective online presence.
Acute In Vitro Effects of Dronedarone, an Iodine-Free Derivative, and Amiodarone, on the Rabbit Sinoatrial Node Automaticity: A Comparative Study
Authors: Celestino Daniela , Medei Emiliano , Moro Sandra , Elizari Marcelo V. , Sicouri Serge
Published: September 2007

Amiodarone is a potent antiarrhythmic drug commonly used in the treatment of supraventricular and ventricular arrhythmias. Dronedarone is a recently developed iodine-free compound (Sanofi Recherche), structurally related to amiodarone. Amiodarone and dronedarone have shown similar long-term effects on sinoatrial node automaticity in vivo and in vitro in the rabbit heart. In the present study, we used a microelectrode technique to compare the acute in vitro electrophysiologic effects of amiodarone (100 µM) and dronedarone (100 µM) on the rabbit sinus node. Like amiodarone, dronedarone induces a marked reduction in sinus node automaticity, evidenced by decreases in spontaneous beating rate, action potential amplitude, and slope of phase 4 depolarization. Isoproterenol dose-dependently increases sinus node automaticity in the presence of either amiodarone or dronedarone. The data suggest that dronedarone may be a useful antiarrhythmic alternative to amiodarone in the treatment of supraventricular arrhythmias.