bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlates of Stimulus-Response Congruence in the Posterior Parietal Cortex
Authors: Stoet Gijsbert , Snyder Lawrence H.
Published: February 2007

Primate behavior is flexible: The response to a stimulus often depends on the task in which it occurs. Here we study how single neurons in the posterior parietal cortex (PPC) respond to stimuli which are associated with different responses in different tasks. Two rhesus monkeys performed a task-switching paradigm. Each trial started with a task cue instructing which of two tasks to perform, followed by a stimulus requiring a left or right button press. For half the stimuli, the associated responses were different in the two tasks, meaning that the task context was necessary to disambiguate the incongruent stimuli. The other half of stimuli required the same response irrespective of task context (congruent). Using this paradigm, we previously showed that behavioral responses to incongruent stimuli are significantly slower than to congruent stimuli. We now demonstrate a neural correlate in the PPC of the additional processing time required for incongruent stimuli. Furthermore, we previously found that 29% of parietal neurons encode the task being performed (task-selective cells). We now report differences in neuronal timing related to congruency in task-selective versus task nonselective cells. These differences in timing suggest that the activity in task nonselective cells reflects a motor command, whereas activity in task-selective cells reflects a decision process.
Who are You Talking About? Tracking Discourse-level Referential Processing with Event-related Brain Potentials
Authors: Nieuwland Mante S. , Otten Marte , Van Berkum Jos J. A.
Published: February 2007

In this event-related brain potentials (ERPs) study, we explored the possibility to selectively track referential ambiguity during spoken discourse comprehension. Earlier ERP research has shown that referentially ambiguous nouns (e.g., “the girl” in a two-girl context) elicit a frontal, sustained negative shift relative to unambiguous control words. In the current study, we examined whether this ERP effect reflects “deep” situation model ambiguity or “superficial” textbase ambiguity. We contrasted these different interpretations by investigating whether a discourse-level semantic manipulation that prevents referential ambiguity also averts the elicitation of a referentially induced ERP effect. We compared ERPs elicited by nouns that were referentially nonambiguous but were associated with two discourse entities (e.g., “the girl” with two girls introduced in the context, but one of which has died or left the scene), with referentially ambiguous and nonambiguous control words. Although temporally referentially ambiguous nouns elicited a frontal negative shift compared to control words, the “double bound” but referentially nonambiguous nouns did not. These results suggest that it is possible to selectively track referential ambiguity with ERPs at the level that is most relevant to discourse comprehension, the situation model.
Individual Differences in Amygdala and Ventromedial Prefrontal Cortex Activity are Associated with Evaluation Speed and Psychological Well-being
Authors: van Reekum Carien M. , Urry Heather L. , Johnstone Tom , Thurow Marchell E. , Frye Corrina J. , Jackson Cory A. , Schaefer Hillary S. , Alexander Andrew L. , Davidson Richard J.
Published: February 2007

Using functional magnetic resonance imaging, we examined whether individual differences in amygdala activation in response to negative relative to neutral information are related to differences in the speed with which such information is evaluated, the extent to which such differences are associated with medial prefrontal cortex function, and their relationship with measures of trait anxiety and psychological well-being (PWB). Results indicated that faster judgments of negative relative to neutral information were associated with increased left and right amygdala activation. In the prefrontal cortex, faster judgment time was associated with relative decreased activation in a cluster in the ventral anterior cingulate cortex (ACC, BA 24). Furthermore, people who were slower to evaluate negative versus neutral information reported higher PWB. Importantly, higher PWB was strongly associated with increased activation in the ventral ACC for negative relative to neutral information. Individual differences in trait anxiety did not predict variation in judgment time or in amygdala or ventral ACC activity. These findings suggest that people high in PWB effectively recruit the ventral ACC when confronted with potentially aversive stimuli, manifest reduced activity in subcortical regions such as the amygdala, and appraise such information as less salient as reflected in slower evaluative speed.
A Review of Functional Imaging Studies on Category Specificity
Authors: Gerlach Christian
Published: February 2007

A review of 20 functional imaging studies that compared visual processing of natural objects and artifacts in normal subjects is presented. The studies included fulfilled three criteria: (i) they used pictures as stimuli, (ii) they were based on direct contrasts between categories, and (iii) they reported findings in Talairach space. Not a single area is consistently activated for a given category across all studies. In contrast, 11 out of 29 regions are reported activated by both artifacts and natural objects. It is argued that the inconsistency is unlikely to reflect differences between studies in task requirements alone. Rather, the most likely causes of the inconsistency are: (i) adoption of liberal statistical thresholds that may yield false-positive activations, (ii) limited sensitivity due to few observations, and (iii) failure to match categories on confounding variables such as familiarity and visual complexity. Of the most consistent activations found, none appear to be selective for natural objects or artifacts. The findings reviewed are compatible with theories of category specificity that assume a widely distributed conceptual system not organized by category.
Enhancing Visuomotor Adaptation by Reducing Error Signals: Single-step (Aware) versus Multiple-step (Unaware) Exposure to Wedge Prisms
Authors: Michel Carine , Pisella Laure , Prablanc Claude , Rode Gilles , Rossetti Yves
Published: February 2007

Neglect patients exhibit both a lack of awareness for the spatial distortions imposed during visuomanual prism adaptation procedures, and exaggerated postadaptation negative after-effects. To better understand this unexpected adaptive capacity in brain-lesioned patients, we investigated the contribution of awareness for the optical shift to the development of prism adaptation. The lack of awareness found in neglect was simulated in a multiple-step group where healthy subjects remained unaware of the optical deviation because of its progressive stepwise increase from 2° to 10°. We contrasted this method with the classical single-step group in which subjects were aware of the visual shift because they were directly exposed to the full 10° shift. Because the number of pointing trials was identical in the two groups, the total amount of deviation exposure was 50% larger in the single-step group. Negative after-effects were examined with an open-loop pointing task performed with the adapted hand, and generalization was tested with open-loop pointing with the nonexposed hand to visual and auditory targets. The robustness of adaptation was assessed by an open-loop pointing task after a simple de-adaptation procedure. The progressive, unaware condition was associated with larger negative after-effects, transfer to the non-exposed hand for the visual and auditory pointing tasks, and greater robustness. The amount of adaptation obtained remained, nevertheless, lower than the exaggerated adaptive capacity seen in patients with neglect. Implications for the functional mechanisms and the anatomical substrates of prism adaptation are discussed.
Austrian Counter-Hegemony
Authors: Karner Christian
Published: February 2007

This article examines select discursive contributions to Austrian civil society as counter-hegemonic forms of engagement with (trans)national structures of power and exclusion. Their ideological opposition is shown to unfold around three thematic areas: (1) conceptualizations of (ethnic) identities that subvert discourses of ethnonationalism; (2) initiatives that challenge everyday racism and asylum seekers’ structural marginalization; (3) a recurring critique of neo-liberalism and economic globalization. The article also demonstrates that the political agency in question is informed by a narrative of interpretation, which partly converges with seminal contributions to the sociology of globalization and which differs radically from neo-nationalist responses to the dislocations and uncertainties of contemporary capitalism.
Licence to Offend?
Authors: Grillo Ralph D.
Published: February 2007

Parekh and Touraine have stressed the importance of intercultural dialogue in the construction of multicultural societies. When, in 2004, the Repertory Theatre in Birmingham, UK, produced Behzti (‘Dishonour’ in Punjabi), by a British-born Sikh playwright, local Sikhs entered into a dialogue with the theatre management and tried unsuccessfully to change aspects of the play they believed offensive to their faith. A demonstration outside the theatre turned violent and the production was halted, with an international outcry against this affront to artistic licence. Although frequently represented as a Manichaean conflict between proponents of free speech and those who sought to protect religious sensibilities, the affair may not have been about, or not mainly about, the clash between religious and secular values at all. It was much more complex, with a diversity of voices and arguments that slithered between principles of liberal and religious faith, culture, gender, and ‘race’.
Political Management of Islamic Fundamentalism
Authors: Alam Anwar
Published: February 2007

This article attempts to explain why and how the Indian state has been successful in managing the militant form of Islamic fundamentalism in India, despite favourable internal and external conditions for such militancy. Internally, it includes such factors as the relative material and cultural deprivation of Indian Muslims, the context of Hindutava and the communal riots, and externally, the Islamic radical movements abroad. Varied literatures have emphasized these factors for the growth of Islamic fundamentalism and Islamic militancy across the Muslim world. However, India has not witnessed large-scale Islamic militancy, despite the growth in Islamic fundamentalist organizations. The article offers a theoretical perspective that takes into consideration the interplay of the nation-building process, the constitutional framework of minority rights, the doctrine of Indian secularism, and the democratic political process. This interplay explains the absence of large-scale militancy and violence, either on the part of Islamic fundamentalist groups/institutions or the Muslim population in India.
‘Blue Squares’, ‘Proper’ Muslims and Transnational Networks
Authors: Hopkins Peter
Published: February 2007

Despite the volume of research about identities of various shapes and forms, few studies have explored young people’s narratives of nation and religion. Drawing on research with young Muslim men in Scotland, this article employs Floya Anthias’s ideas about narratives of location, dislocation and positionality in order to seek a deeper understanding and appreciation of the young men’s national and religious identities and affiliations. Although the majority of the young men identify as Scottish Muslims, the meanings and associations of these identity markers vary in strength, nature and meaning, and the young men are also connected with a global network of identifications linking them with family heritages in Asia and Africa.
Europe in the Middle East and Northern Africa: The Subtle Quest for Power
Authors: Saleh Nivien
Published: February 2007

Nivien Saleh is a visiting professor in political science at Northern Arizona University.
Europe's Muslim Youth: An Inquiry into the Politics of Discrimination, Relative Deprivation, and Identity Formation
Authors: Franz Barbara
Published: February 2007

Barbara Franz is assistant professor of political science at Rider University, Lawrenceville, New Jersey.
Legislative Provisions of the Ottoman/Turkish Governments Regarding Minorities and Their Properties
Authors: Lekka Anastasia
Published: February 2007

Anastasia Lekka lectures on international relations and contemporary political currents in Turkey at the University of the Aegean. She is author of the book The European Union and Regional Cooperation in Europe.
Ordered Microdomain of Diprotonated Tetraphenylporphine Aggregate Formed at Dodecane/Aqueous H2SO4 Interface Measured by Microspectrophotometry
Authors: Kamiya Yukio , Tsukahara Satoshi , Fujiwara Terufumi
Published: February 2007

In situ microscopic measurements showed that rhombic microdomains of diprotonated 5,10,15,20-tetraphenylporphine aggregates were formed at a dodecane/aqueous H2SO4 interface. The size and thickness of the microdomains were about 10–100 μm and a monolayer level, respectively. The microscopic absorption anisotropy of individual microdomains revealed that they had an ordered structure, like single crystals.
Amphiphilic Pyranines: Chromophore Wrapped in a Hydrophobic Alkyl Chain and Micelle Formation Induced by Complexation with Methylviologen
Authors: Sasaki Ryo , Murata Shigeru
Published: February 2007

Amphiphilic pyranines POCn (n = 8, 12, and 16) were synthesized, and their aggregation behaviors were investigated in water. 1H NMR studies implied that POC16 existed in the conformation of the pyranine chromophore wrapped with a hexadecyl methylene chain, which showed no indication of aggregation at the concentration up to 10−4 M. However, the formation of micelles was readily induced by the addition of methylviologen (MV2+) to a POC16 solution, which was responsible for an apparent large complexation constant of ca. 106 M−1.
Reduction of α,β-Unsaturated Ketones with Diphenylsilanes Bearing Several Substituents on Their Phenyl Moiety Catalyzed by Rhodium–Phosphine Complexes
Authors: Imao Daisuke , Hayama Miyuki , Ishikawa Kohta , Ohta Tetsuo , Ito Yoshihiko
Published: February 2007

1,4-Addition product was afforded exclusively by rhodium–phosphine complex-catalyzed hydrosilylation by using 2-cyclohexen-1-one and a dihydrosilane bearing an ether substituent in spite of the fact that dihydrosilanes were believed to give 1,2-addition product selectively.
Blue Luminescence from a Thin Film of the AlQ3/SiO2 Organic–Inorganic Hybrid Material
Authors: Zeng Hong-Yu , Huang Wei-Min , Shi Jian-Lin
Published: February 2007

We report an effective method to the high quality fabrication of the AlQ3/SiO2 organic–inorganic hybrid film with a blue luminescent under a UV light excitation. The high quality AlQ3/SiO2 film preparation makes the hybrid material a key step forward to the applications in OLEDs.
Microwave-assisted Preparation of Bi2Te3 Hollow Nanospheres
Authors: Jiang Ya , Zhu Ying-Jie , Chen Li-Dong
Published: February 2007

Bi2Te3 hollow nanospheres with diameters of 50–100 nm have been successfully prepared using TeO2, Bi(NO3)3, and HNO3 in mixed solvents of water and ethylene glycol by a simple microwave heating method at 150 °C for 30 min.
Zn1−xMgxO Nanoparticles: Solvothermal Synthesis and Solid Solubility
Authors: Qiu Xiaoqing , Xue Yanfeng , Li Guangshe , Li Liping
Published: February 2007

This work reports on the direct preparation of Zn1−xMgxO nanoparticles by a solvothermal condition, in which the formation of kinetically stable Mg(OH)2 was significantly suppressed. The reactions do not need any heat treatment procedures. Structural and spectral analyses indicated that Mg2+ ions were incorporated into the lattice of ZnO with a solid solubility of about 4.25%. With increasing the Mg content, the E2 mode of ZnO lattice showed a systematic shift towards higher energies, which was explained in terms of an effective mass model.
The Multifaceted Nature of Exploration and Exploitation: Value of Supply, Demand, and Spatial Search for Innovation
Authors: Sidhu Jatinder S. , Commandeur Harry R. , Volberda Henk W.
Published: February 2007

In this paper, exploration and exploitation are conceptualized in terms of a nonlocal-local search continuum in three-dimensional supply, demand, and geographic space. Using cross-sectional data from a wide range of manufacturing industries, we develop and validate an operational measure of the exploration-exploitation concept. In line with theory-based arguments, our analysis suggests that the value of supply-side, demand-side, and spatial exploration and exploitation is contingent on the environment. While boundary-spanning supply-side search is found to be positively associated with innovation in more-dynamic environments typical of the entrepreneurial regime phase of technology evolution, such exploration appears to hurt innovation in less-dynamic environments. In a reverse fashion, while boundary-spanning demand-side search is found to be favorably associated with innovation in less-dynamic environments, it appears to harm innovation in a more-dynamic context. Interestingly, spatial boundary-spanning search seems to contribute to innovation in more- as well as less-dynamic environments. With the caveat that the substantive findings of this study are based on cross-sectional data, we discuss the implications of our work and future research directions.
Two Faces of Search: Alternative Generation and Alternative Evaluation
Authors: Knudsen Thorbjørn , Levinthal Daniel A.
Published: February 2007

At its core, a behavioral theory of choice has two fundamental attributes that distinguish it from traditional economic models of decision making. One attribute is that choice sets are not available ex ante to actors, but must be constructed. This notion is well established in our models of learning and adaptation. The second fundamental postulate is that the evaluation of alternatives is likely to be imperfect. Despite the enshrinement of the notion of bounded rationality in the organizations literature, this second postulate has been largely ignored in our formal models of learning and adaptation. We develop a structure with which to capture the imperfect evaluation of alternatives at the individual level and then explore the implications of alternative organizational structures, comprising such individual actors, on organizational decision making.
Complementarity and Evolution of Contractual Provisions: An Empirical Study of IT Services Contracts
Authors: Argyres Nicholas S. , Bercovitz Janet , Mayer Kyle J.
Published: February 2007

An increasing volume of business activity appears to be occurring via alliances or other interfirm arrangements in which complex contracts are featured, yet there has been relatively little study of contract design in the strategy or management literatures. The economics literature on contracting has been extensive, but it has been less concerned with learning and evolution—phenomena in which strategy and organization scholars are deeply interested. In this paper, we investigate the relationship between two types of contractual provisions that are important in high-technology contracts, or contracts for which environmental uncertainty or technological complexity are significant, namely, contingency planning and task description. Previous research suggests that contracts can vary significantly in the degree of detail with which such key provisions are written, and that they are each subject to learning. In this paper, we find evidence from a sample of 386 contracts that contingency planning and task description behave as complements in contractual design. We argue that this complementarity reflects patterns of learning to contract. We also find that repeated exchange between two firms leads to greater effort at contingency planning in subsequent contracts, a finding that is also consistent with learning effects, but not with frequently made claims that contracts and trust are substitutes.
Corporate Greening Through ISO 14001: A Rational Myth?
Authors: Boiral Olivier
Published: February 2007

The process used by organizations to integrate the ISO 14001 standard has not yet been the subject of extensive research in environmental management despite the rapid development of this standard, particularly in industrial companies. The results of a case study conducted among nine ISO 14001 certified Canadian organizations showed that adopting this standard tends to lead to a ceremonial behaviour intended to superficially show that the certified organizations conformed to the standard. Although rigorous compliance with the standard often resulted in real improvements, these improvements were primarily technical and administrative in nature. However, in most of the cases studied, daily practices remained somewhat decoupled from the prescriptions of the ISO 14001 system, of which employees generally had only a vague understanding. The organizations studied adopted different strategies to reconcile external pressures in favour of adopting this standard and internal constraints associated with a management system whose support varied from one case to the next. While the standard often appeared to be some sort of “rational myth” (Meyer and Rowan 1977) to which organizations superficially committed themselves, the adaptation to institutional pressures was not necessarily straightforward. Using the example of the ISO 14001 standard, our study helps to show how this myth can be integrated, transformed, and even created through rhetoric by organizations to resolve certain contradictions. This research also illustrates how adopting the ISO 14001 system can have an ambiguous effect on environmental management practices and performances.
A Triple Take on Information System Implementation
Authors: Lapointe Liette , Rivard Suzanne
Published: February 2007

While researchers have used a variety of models to explain information system (IS) implementation outcomes, few have analyzed the same project or set of projects with different models looking for complementary explanations. Recognizing the multilevel nature of IS implementation, our study rises to this challenge by conducting an alternate template analysis of three cases of IS implementation in hospitals. First, we explain individual use, group resistance, and organizational adoption with models situated at the same level of analysis as each outcome. At the individual level, we use a model of cognitive absorption to explain individual system usage. At the group level, the political variant of interaction theory is used to explain group resistance to IS implementation. At the organizational level, we use organizational configurations to explain IS adoption in terms of emergence and routinization. We identify each model’s limits and prediction failures, and we show that using alternate models helps to remedy a model’s prediction failures and overcome its limits. Finally, we propose an alternate-template theory of IS implementation outcomes that takes into account all three levels of analysis, their respective outcomes, and the time dimension. This multilevel, longitudinal theory provides a better understanding of IS implementation and further elucidates what may initially have seemed to be contradictory results.
The influence of intra‐team conflict on work teams' affective climate: A longitudinal study
Authors: Gamero Nuria , González‐Romá Vicente , Peiró José M.
Published: February 2007

We analysed whether relationship conflict mediates the link between task conflict and shared affect at the team level of analysis. Moreover, we tested the hypothesis that the relationship between these two types of intra‐team conflict would be moderated by team members' interaction. The sample was composed of 156 bank branches. Data were gathered at two points in time. Two affect dimensions (tension and enthusiasm) were measured. The results obtained supported our hypotheses. Relationship conflict fully mediated the relationship between task conflict and team affect. Team members' interaction about team issues moderated the relationship between task conflict and relationship conflict, so that when team members' interaction was low, the relationship enhanced, whereas when team members' interaction was high, the relationship weakened.
Effects of abstinence from habitual involvement in regular exercise on feeling states: An ecological momentary assessment study
Authors: Hausenblas Heather A. , Gauvin Lise , Downs Danielle Symons , Duley Aaron R.
Published: February 2007

Regular exercise was experimentally reduced to determine its effects on positive feeling states. Using ecological momentary assessments, 40 participants maintained their regular exercise routine on 3 days and were deprived of their scheduled exercise on 3 other days. They recorded their feeling states, using the Exercise‐Induced Feeling Inventory, four times daily as well as prior to and following exercise. Multi‐level modelling analyses controlling for diurnal variations in feeling states revealed that positive feeling states were elevated on days when exercise deprivation occurred compared with non‐exercise days and when no deprivation manipulation occurred. People with lower exercise dependence symptoms felt better on days when they were deprived from exercise compared with non‐exercise days, whereas people with higher exercise dependence symptoms felt about the same when they were deprived from exercise compared with non‐exercise days. These findings demonstrate that positive feeling states occur following an acute bout of exercise and that exercise deprivation had a positive impact on feeling states, with the level of exercise dependence symptoms moderating this effect.
"Explorations in Dot-and-Dashland": George Meredith's Aphasia
Authors: Henry Anne C.
Published: February 2007

George Meredith's writing is notorious for its "obscurity." This essay examines that obscurity through the punctuation that Meredith employed, in particular his use of ellipsis marks. Throughout his novelistic career Meredith attempted to capture the nebulousness of both thought and speech by means of a difficult and elliptical syntax and by using the punctuation of ellipsis: dashes and suspension points (though the latter are more commonly associated with later,modernist writers). This essay addresses Meredith's fascination with the unarticulated and inarticulate, as well as his attitudes toward transcription. His 1881 novel The Tragic Comedians is of particular importance in this analysis, as there he traced explicitly one of his character's "explorations in Dot-and-Dashland."The revisions that Meredith made to the manuscript of The Tragic Comedians underline his profound commitment to scrutiny and criticism of that which is obscure in our experiences and interactions, however his detractors used this against him.
Genetic Mapping in the Presence of Genotyping Errors
Authors: Cartwright Dustin A , Troggio Michela , Velasco Riccardo , Gutin Alexander
Published: February 2007

Genetic maps are built using the genotypes of many related individuals. Genotyping errors in these data sets can distort genetic maps, especially by inflating the distances. We have extended the traditional likelihood model used for genetic mapping to include the possibility of genotyping errors. Each individual marker is assigned an error rate, which is inferred from the data, just as the genetic distances are. We have developed a software package, called TMAP, which uses this model to find maximum-likelihood maps for phase-known pedigrees. We have tested our methods using a data set in Vitis and on simulated data and confirmed that our method dramatically reduces the inflationary effect caused by increasing the number of markers and leads to more accurate orders.
The Evolution of Sex and Recombination in Response to Abiotic or Coevolutionary Fluctuations in Epistasis
Authors: Gandon Sylvain , Otto Sarah P
Published: February 2007

Evolutionary biologists have identified several factors that could explain the widespread phenomena of sex and recombination. One hypothesis is that host–parasite interactions favor sex and recombination because they favor the production of rare genotypes. A problem with many of the early models of this so-called Red Queen hypothesis is that several factors are acting together: directional selection, fluctuating epistasis, and drift. It is thus difficult to identify what exactly is selecting for sex in these models. Is one factor more important than the others or is it the synergistic action of these different factors that really matters? Here we focus on the analysis of a simple model with a single mechanism that might select for sex: fluctuating epistasis. We first analyze the evolution of sex and recombination when the temporal fluctuations are driven by the abiotic environment. We then analyze the evolution of sex and recombination in a two-species coevolutionary model, where directional selection is absent (allele frequencies remain fixed) and temporal variation in epistasis is induced by coevolution with the antagonist species. In both cases we contrast situations with weak and strong selection and derive the evolutionarily stable (ES) recombination rate. The ES recombination rate is most sensitive to the period of the cycles, which in turn depends on the strength of epistasis. In particular, more virulent parasites cause more rapid cycles and consequently increase the ES recombination rate of the host. Although the ES strategy is maximized at an intermediate period, some recombination is favored even when fluctuations are very slow. By contrast, the amplitude of the cycles has no effect on the ES level of sex and recombination, unless sex and recombination are costly, in which case higher-amplitude cycles allow the evolution of higher rates of sex and recombination. In the coevolutionary model, the amount of recombination in the interacting species also has a large effect on the ES, with evolution favoring higher rates of sex and recombination than in the interacting species. In general, the ES recombination rate is less than or equal to the recombination rate that would maximize mean fitness. We also discuss the effect of migration when sex and recombination evolve in a metapopulation. We find that intermediate parasite migration rates maximize the degree of local adaptation of the parasite and lead to a higher ES recombination rate in the host.
Power and Precision of Alternate Methods for Linkage Disequilibrium Mapping of Quantitative Trait Loci
Authors: Zhao H H , Fernando R L , Dekkers J C M
Published: February 2007

Linkage disequilibrium (LD) analysis in outbred populations uses historical recombinations to detect and fine map quantitative trait loci (QTL). Our objective was to evaluate the effect of various factors on power and precision of QTL detection and to compare LD mapping methods on the basis of regression and identity by descent (IBD) in populations of limited effective population size (Ne). An 11-cM region with 6–38 segregating single-nucleotide polymorphisms (SNPs) and a central QTL was simulated. After 100 generations of random mating with Ne of 50, 100, or 200, SNP genotypes and phenotypes were generated on 200, 500, or 1000 individuals with the QTL explaining 2 or 5% of phenotypic variance. To detect and map the QTL, phenotypes were regressed on genotypes or (assumed known) haplotypes, in comparison with the IBD method. Power and precision to detect QTL increased with sample size, marker density, and QTL effect. Power decreased with Ne, but precision was affected little by Ne. Single-marker regression had similar or greater power and precision than other regression models, and was comparable to the IBD method. Thus, for rapid initial screening of samples of adequate size in populations in which drift is the primary force that has created LD, QTL can be detected and mapped by regression on SNP genotypes without recovering haplotypes.
How Repeatable Are Associations Between Polymorphisms inachaete–scuteand Bristle Number Variation in Drosophila?
Authors: Gruber Jonathan D , Genissel Anne , Macdonald Stuart J , Long Anthony D
Published: February 2007

Currently, the relevance of common genetic variants—particularly those significantly associated with phenotypic variation in laboratory studies—to standing phenotypic variation in the wild is poorly understood. To address this, we quantified the relationship between achaete–scute complex (ASC) polymorphisms and Drosophila bristle number phenotypes in several new population samples. MC22 is a biallelic, nonrepetitive-length polymorphism 97 bp downstream of the scute transcript. It has been previously shown to be associated with sternopleural bristle number variation in both sexes in a set of isogenic lines. We replicated this association in a large cohort of wild-caught Drosophila melanogaster. We also detected a significant association at MC22 in an outbred population maintained under laboratory conditions for ∼25 years, but the phenotypic effects in this sample were opposite from the direction estimated in the initial study. Finally, no significant associations were detected in a second large wild-caught cohort or in a set of 134 nearly isogenic lines. Our ability to repeat the initial association in wild samples suggests that it was not spurious. Nevertheless, inconsistent results from the other three panels suggest that the relationship between polymorphic genetic markers and loci contributing to continuous variation is not a simple one.
Brc1-Mediated Rescue of Smc5/6 Deficiency: Requirement for Multiple Nucleases and a Novel Rad18 Function
Authors: Lee Karen M , Nizza Suzanne , Hayes Thomas , Bass Kirstin L , Irmisch Anja , Murray Johanne M , O'Connell Matthew J
Published: February 2007

Smc5/6 is a structural maintenance of chromosomes complex, related to the cohesin and condensin complexes. Recent studies implicate Smc5/6 as being essential for homologous recombination. Each gene is essential, but hypomorphic alleles are defective in the repair of a diverse array of lesions. A particular allele of smc6 (smc6-74) is suppressed by overexpression of Brc1, a six-BRCT domain protein that is required for DNA repair during S-phase. This suppression requires the postreplication repair (PRR) protein Rhp18 and the structure-specific endonucleases Slx1/4 and Mus81/Eme1. However, we show here that the contribution of Rhp18 is via a novel pathway that is independent of PCNA ubiquitination and PRR. Moreover, we identify Exo1 as an additional nuclease required for Brc1-mediated suppression of smc6-74, independent of mismatch repair. Further, the Apn2 endonuclease is required for the viability of smc6 mutants without extrinsic DNA damage, although this is not due to a defect in base excision repair. Several nucleotide excision repair genes are similarly shown to ensure viability of smc6 mutants. The requirement for excision factors for the viability of smc6 mutants is consistent with an inability to respond to spontaneous lesions by Smc5/6-dependent recombination.
TheflamencoLocus Controls thegypsyandZAMRetroviruses and Is Required for Drosophila Oogenesis
Authors: Mével-Ninio Maryvonne , Pelisson Alain , Kinder Jennifer , Campos Ana Regina , Bucheton Alain
Published: February 2007

In Drosophila, the as yet uncloned heterochromatic locus flamenco (flam) controls mobilization of the endogenous retrovirus gypsy through the repeat-associated small interfering (rasi) RNA silencing pathway. Restrictive alleles (flamR) downregulate accumulation of gypsy transcripts in the somatic follicular epithelium of the ovary. In contrast, permissive alleles (flamP) are unable to repress gypsy. DIP1, the closest transcription unit to a flam-insertional mutation, was considered as a good candidate to be a gypsy regulator, since it encodes a dsRNA-binding protein. To further characterize the locus we analyzed P-induced flam mutants and generated new mutations by transposon mobilization. We show that flam is required somatically for morphogenesis of the follicular epithelium, the tissue where gypsy is repressed. This developmental activity is necessary to control gypsy and another retroelement, ZAM. We also show that flam is not DIP1, as none of the new permissive mutants affect the DIP1 coding sequence. In addition, two deletions removing DIP1 coding sequences do not affect any of the flamenco functions. Our results suggest that flamenco extends proximally to DIP1, spanning >130 kb of transposon-rich heterochromatin. We propose a model explaining the multiple functions of this large heterochromatic locus.
Evaluation of a Surface Flow Bypass System for Steelhead Kelt Passage at Bonneville Dam, Washington
Authors: Wertheimer Robert H.
Published: February 2007

A surface flow bypass system for juvenile Pacific salmon Oncorhynchus spp. began operation at the second powerhouse (B2) of Bonneville Dam on the lower Columbia River in spring 2004. This surface bypass, called the “B2 corner collector,” is the result of extensive modification of the original B2 sluice chute. Because steelhead O. mykiss are iteroparous, the effect of this bypass and the unmodified sluiceway at the older first powerhouse (B1) on downstream migration of postspawn steelhead (i.e., kelts) may be an important factor in the rate of iteroparity. As such, passage at Bonneville Dam (river kilometer (rkm) 234, measured from the mouth of the Columbia River) was examined to understand the efficiency of surface bypass in passing kelts. Steelhead kelts were collected, radio-tagged, and volitionally released from the juvenile bypass facilities at McNary Dam (rkm 465) and John Day Dam (rkm 345) on the Columbia River during spring 2004. Forebay residence times for kelts passing via B2 (with the corner collector operating) were significantly reduced relative to residence times published from a prior period with similar water flows at B2 (2002). Passage efficiency (nonturbine passage) at B2 significantly increased in relation to this same period. Over 80% of kelts at B2 and nearly the same percentage at B1 were routed away from turbines via surface flow routes passing up to 5% of total discharge at each powerhouse, indicating that relatively small amounts of surface flow are needed to pass kelts via nonturbine routes. Providing surface flow passage routes may provide an efficient means of bolstering iteroparity rates by increasing the number of kelts that successfully navigate Bonneville Dam during the spring.
Characterisation of proghrelin peptides in mammalian tissue and plasma
Authors: Bang Angela S , Soule Steven G , Yandle Tim G , Richards A Mark , Pemberton Chris J
Published: February 2007

Ghrelin is a 28 amino acid stomach peptide, derived from proghrelin(1–94), that stimulates GH release, appetite and adipose deposition. Recently, a peptide derived from proghrelin(53–75) – also known as obestatin – has been reported to be a physiological antagonist of ghrelin in the rat. Using four specific RIAs, we provide the first characterisation of proghrelin(1–94) peptides in human plasma, their modulation by metabolic manipulation and their distribution in mammalian tissues. ghrelin(1–28) immunoreactivity (IR) in human plasma and rat plasma/stomach consisted of major des-octanoyl and minor octanoylated forms, as determined by HPLC/RIA. Human plasma ghrelin(1–28) IR was significantly suppressed by food intake, oral glucose and 1 mg s.c. glucagon administration. ghrelin(1–28) IR and proghrelin(29–94) IR peptide distributions in the rat indicated that the stomach and gastrointestinal tract contain the highest amounts of the peptides. Human and rat plasma and rat stomach extracts contained a major IR peak of proghrelin(29–94)-like peptide as determined by HPLC/RIA, whereas no obestatin IR was observed. Human plasma proghrelin(29–94)-like IR positively correlated with ghrelin(1–28) IR, was significantly suppressed by food intake and oral glucose and shared with ghrelin(1–28) IR a negative correlation with body mass index. We found no evidence for the existence of obestatin as a unique, endogenous peptide. Rather, our data suggest that circulating and stored peptides derived from the carboxyl terminal of proghrelin (C-ghrelin) are consistent in length with proghrelin(29–94) and respond to metabolic manipulation, at least in man, in similar fashion to ghrelin(1–28).
Characterisation of 11β-hydroxysteroid dehydrogenase 1 in human orbital adipose tissue: a comparison with subcutaneous and omental fat
Authors: Bujalska Iwona J , Durrani Omar M , Abbott Joseph , Onyimba Claire U , Khosla Pamela , Moosavi Areeb H , Reuser Tristan T Q , Stewart Paul M , Tomlinson Jeremy W , Walker Elizabeth A , Rauz Saaeha
Published: February 2007

Glucocorticoids (GCs) have a profound effect on adipose biology increasing tissue mass causing central obesity. The pre-receptor regulation of GCs by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) that activates cortisol from cortisone has been postulated as a fundamental mechanism underlying the metabolic syndrome mediating adipocyte hyperplasia and hypertrophy in the omental (OM) depot. Orbital adipose tissue (OF) is the site of intense inflammation and tissue remodelling in several orbital inflammatory disease states. In this study, we describe features of the GC metabolic pathways in normal human OF depot and compare it with subcutaneous (SC) and OM depots. Using an automated histological characterisation technique, OF adipocytes were found to be significantly smaller (parameters: area, maximum diameter and perimeter) than OM and SC adipocytes (P<0.001). Although immunohistochemical analyses demonstrated resident CD68+ cells in all three whole tissue adipose depots, OF CD68 mRNA and protein expression exceeded that of OM and SC (mRNA, P<0.05; protein, P<0.001). In addition, there was higher expression of glucocorticoid receptor (GR)α mRNA in the OF whole tissue depot (P<0.05). Conversely, 11β-HSD1 mRNA together with the markers of late adipocyte differentiation (FABP4 and G3PDH) were significantly lower in OF. Primary cultures of OF preadipocytes demonstrated predominant 11β-HSD1 oxo-reductase activity with minimal dehydrogenase activity. Orbital adipocytes are smaller, less differentiated, and express low levels of 11β-HSD1 but abundant GRα compared with SC and OM. OF harbours a large CD68+ population. These characteristics define an orbital microenvironment that has the potential to respond to sight-threatening orbital inflammatory disease.
Glucocorticoid feedback control of corticotropin in the hypoxic neonatal rat
Authors: Raff Hershel , Jacobson Lauren
Published: February 2007

The objective of this study was to determine the effects of manipulating glucocorticoid negative feedback on acute ACTH and corticosterone responses to corticotropin-releasing hormone (CRH) injection in 7-day-old rats exposed to normoxia or hypoxia from birth. Chemical adrenalectomy was achieved with aminoglutethimide, and glucocorticoids were replaced with a low dose of dexamethasone. Hypoxia per se increased basal plasma corticosterone and attenuated the plasma ACTH response to CRH. Aminoglutethimide per se decreased plasma corticosterone and strongly increased basal plasma ACTH and anterior pituitary POMC gene expression. Dexamethasone partially attenuated elevations in basal plasma ACTH due to aminoglutethimide in both normoxic and hypoxic pups, but inhibited anterior pituitary POMC expression and CRH-induced plasma ACTH only in hypoxic pups. Despite this inhibition, hypoxic pups treated with both dexamethasone and aminoglutethimide still exhibited a significant CRH-induced increment in plasma ACTH, which was lacking in hypoxic pups not treated with either dexamethasone or aminoglutethimide. We conclude that ACTH responses to acute stimuli in hypoxic neonatal rats are prevented by ACTH-independent increases in corticosterone, rather than by intrinsic hypothalamic–pituitary hypoactivity.
The influence of 17β-estradiol on annexin 1 expression in the anterior pituitary of the female rat and in a folliculo-stellate cell line
Authors: Davies Evelyn , Omer Selma , Morris John F , Christian Helen C
Published: February 2007

Annexin 1 (ANXA1) is a Ca2+- and phospholipid-binding protein that plays an important role as a mediator of glucocorticoid action in the host-defence and neuroendocrine systems. Sex differences in hypothalamo–pituitary–adrenal (HPA) axis activity are well documented and a number of studies have demonstrated that gonadal steroids act as regulators of HPA activity. The aim of this study was to investigate the effect of ovariectomyand 17β-estradiol replacement, and estrous cycle stage, on anterior pituitary ANXA1 content. The amount of anterior pituitary ANXA1 determined by western blotting varied with estrous cycle stage with a peak at estrus declining to a trough at proestrus. Ovariectomy resulted in a significant (P<0.05) decrease in anterior pituitary ANXA1 content. Administration of 17β-estradiol (1 μg/100 g) significantly (P<0.01) increased anterior pituitary ANXA1 expression in the ovariectomized animals. In contrast, there was no change in pituitary ANXA1 content in response to 17β-estradiol in adrenalectomized and adrenalectomized/ovariectomized rats. Treatment of TtT/GF cells, a folliculo-stellate cell line, with 17β-estradiol (1.8–180 nM) increased ANXA1 mRNA expression and increased the amount of ANXA1 protein externalized in response to a dexamethasone stimulus. These results indicate that 17β-estradiol stimulates ANXA1 expression in the anterior pituitary and in vivo an adrenal factor contributes to the mechanism of action.
Altered proinsulin conversion in rat pancreatic islets exposed long-term to various glucose concentrations or interleukin-1β
Authors: Börjesson Andreas , Carlsson Carina
Published: February 2007

In order to elucidate a possible relationship between β-cell function and conversion of proinsulin to insulin, isolated rat pancreatic islets were maintained in tissue culture for 1 week at various glucose concentrations (5.6–56 mM). Studies were also conducted on islets cultured for 48 h with interleukin-1β (IL-1β). By pulse-chase labelling and immunoprecipitation, the relative contents of newly synthesized proinsulin and insulin were determined. ELISA was used to analyse insulin and proinsulin content in medium and within islets. Using real-time PCR, the mRNA levels of proinsulin converting enzymes (PC1 and PC2) were studied. Islets cultured at 56 mM glucose had an increased proportion of newly synthesized proinsulin when compared with islets cultured at 5.6 mM glucose after a 90-min chase periods, however, no difference was observed after culture at 11 and 28 mM glucose. ELISA measurements revealed that culture at increased glucose concentrations as well as islet exposure to IL-1β increased proinsulin accumulation in the culture media. The mRNA expression of PC1 was increased after culture at 11 and 28 mM glucose. Treatment for 48 h with IL-1β increased the proportion of proinsulin both at 45 and 90 min when compared with control islets. These islets also displayed a decreased mRNA level of PC1 as well as PC2. Calculations of the half-time for proinsulin demonstrated a significant prolongation after treatment with IL-1β. We conclude that a sustained functional stimulation by glucose of islets is coupled to a decreased conversion of proinsulin which is also true for islets treated with IL-1β. This may contribute to the elevated levels of proinsulin found both at the onset of type 1 diabetes as well as in type 2 diabetes.