bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlates of Stimulus-Response Congruence in the Posterior Parietal Cortex
Authors: Stoet Gijsbert , Snyder Lawrence H. 
Published: February 2007

Abstract
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

Abstract
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

Abstract
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

Abstract
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

AbstractNeglect 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.
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.
Genetic Mapping in the Presence of Genotyping Errors
Authors: Cartwright Dustin A , Troggio Michela , Velasco Riccardo , Gutin Alexander 
Published: February 2007

Abstract
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

Abstract
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

Abstract
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

AbstractCurrently, 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

Abstract
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

AbstractIn 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 &gt;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

Abstract
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.