bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Spatial Statistical Model for Landscape Genetics
Authors: Guillot Gilles , Estoup Arnaud , Mortier Frédéric , Cosson Jean François 
Published: November 2004

AbstractLandscape genetics is a new discipline that aims to provide information on how landscape and environmental features influence population genetic structure. The first key step of landscape genetics is the spatial detection and location of genetic discontinuities between populations. However, efficient methods for achieving this task are lacking. In this article, we first clarify what is conceptually involved in the spatial modeling of genetic data. Then we describe a Bayesian model implemented in a Markov chain Monte Carlo scheme that allows inference of the location of such genetic discontinuities from individual geo-referenced multilocus genotypes, without a priori knowledge on populational units and limits. In this method, the global set of sampled individuals is modeled as a spatial mixture of panmictic populations, and the spatial organization of populations is modeled through the colored Voronoi tessellation. In addition to spatially locating genetic discontinuities, the method quantifies the amount of spatial dependence in the data set, estimates the number of populations in the studied area, assigns individuals to their population of origin, and detects individual migrants between populations, while taking into account uncertainty on the location of sampled individuals. The performance of the method is evaluated through the analysis of simulated data sets. Results show good performances for standard data sets (e.g., 100 individuals genotyped at 10 loci with 10 alleles per locus), with high but also low levels of population differentiation (e.g., FST &lt; 0.05). The method is then applied to a set of 88 individuals of wolverines (Gulo gulo) sampled in the northwestern United States and genotyped at 10 microsatellites.
Naturally Segregating Quantitative Trait Loci Affecting Wing Shape of Drosophila melanogaster
Authors: Mezey Jason G , Houle David , Nuzhdin Sergey V 
Published: November 2004

Abstract
Variation in vein position and wing shape of Drosophila melanogaster depends on many genes. In the following, we report the results of a QTL analysis of wing shape in D. melanogaster. We identified QTL responsible for natural variation for wing shape and analyzed their interactions with developmental genetic signaling pathways important for vein positioning. The QTL analysis indicated that the total number of QTL segregating in this population is likely to be very large. The locations of putative QTL identified in this study were compared to those identified in previous studies and, while there is more correspondence across studies than expected by chance on the third chromosome, the studies appear to have identified different QTL. Using a complementation design, we tested for interactions among these QTL with the Hedgehog and Decapentaplegic signaling pathways, which are important for the development and position of vein pairs L3-L4 and L2-L5. Three QTL showed strong interactions with these two pathways, supporting the hypothesis that these QTL are involved in these pathways. Naturally segregating variation can therefore act through known signaling pathways to produce variation in vein position.
How well does the finite Fourier transform approximate the Fourier transform?
Authors: Epstein Charles L. 
Published: November 2004

AbstractWe show that the answer to the question in the title is “very well indeed.” In particular, we prove that, throughout the maximum possible range, the finite Fourier coefficients provide a good approximation to the Fourier coefficients of a piecewise continuous function. For a continuous periodic function, the size of the error is estimated in terms of the modulus of continuity of the function. The estimates improve commensurately as the functions become smoother. We also show that the partial sums of the finite Fourier transform provide essentially as good an approximation to the function and its derivatives as the partial sums of the ordinary Fourier series. Along the way we establish analogues of the Riemann‐Lebesgue lemma and the localization principle. © 2004 Wiley Periodicals, Inc.
A pilot study of behavioural and psychological signs and symptoms of dementia in patients of Indian sub‐continent origin admitted to a dementia day hospital in the United Kingdom
Authors: Haider Imran , Shah Ajit 
Published: November 2004

AbstractBackgroundThere is a paucity of cross‐cultural studies of behavioural and psychological symptoms of dementia (BPSD).MethodBPSD were examined in a consecutive series of Indian sub‐continent origin and white indigenous elders admitted to a dementia day hospital using the BEHAVE‐AD. The correlates of individual BPSD in each of the two ethnic groups and the differences between the two ethnic groups were examined.ResultsThere were no differences between the two groups on most of the demographic and clinical variables examined, except that Indian sub‐continent elders had a greater number of children. There were no differences between the two groups on the MMSE scores, BEHAVE‐AD total scores and BEHAVE‐AD subscale scores (with one exception). Indian sub‐ continent origin patients had lower scores on the anxiety and phobias subscale. Within the Indian sub‐continent origin group, Alzheimer's disease (AD) was associated with activity disturbance and vascular dementia with affective disturbance. Within the indigenous group, aggressivity was associated with males and prescription of neuroleptics, and affective disturbance with prescription of antidepressants.ConclusionThere is a need to develop and evaluate translated versions of instruments that measure BPSD. After development of these instruments there is a need for cross‐cultural population‐based epidemiological studies of BPSD. Copyright © 2004 John Wiley & Sons, Ltd.
Predicting absolute contact numbers of native protein structure from amino acid sequence
Authors: Kinjo Akira R. , Horimoto Katsuhisa , Nishikawa Ken 
Published: November 2004

AbstractThe contact number of an amino acid residue in a protein structure is defined by the number of Cβ atoms around the Cβ atom of the given residue, a quantity similar to, but different from, solvent accessible surface area. We present a method to predict the contact numbers of a protein from its amino acid sequence. The method is based on a simple linear regression scheme and predicts the absolute values of contact numbers. When single sequences are used for both parameter estimation and cross‐validation, the present method predicts the contact numbers with a correlation coefficient of 0.555 on average. When multiple sequence alignments are used, the correlation increases to 0.627, which is a significant improvement over previous methods. In terms of discrete states prediction, the accuracies for 2‐, 3‐, and 10‐state predictions are, respectively, 71.4%, 54.1%, and 18.9% with residue type‐dependent unbiased thresholds, and 76.3%, 59.2%, and 21.8% with residue type‐independent unbiased thresholds. The difference between accessible surface area and contact number from a prediction viewpoint and the application of contact number prediction to three‐dimensional structure prediction are discussed. Proteins 2005. © 2004 Wiley‐Liss, Inc.
Early events in protein aggregation: Molecular flexibility and hydrophobicity/charge interaction in amyloid peptides as studied by molecular dynamics simulations
Authors: Valerio Mariacristina , Colosimo Alfredo , Conti Filippo , Giuliani Alessandro , Grottesi Alessandro , Manetti Cesare , Zbilut Joseph P. 
Published: November 2004

AbstractIn a previous article (Zbilut et al., Biophys J 2003;85:3544–3557), we demonstrated how an aggregation versus folding choice could be approached considering hydrophobicity distribution and charge. In this work, our aim is highlighting the mutual interaction of charge and hydrophobicity distribution in the aggregation process. Use was made of two different peptides, both derived from a transmembrane protein (amyloid precursor protein; APP), namely, Aβ(1‐28) and Aβ(1‐40). Aβ(1‐28) has a much lower aggregation propensity than Aβ(1‐40). The results obtained by means of molecular dynamics simulations show that, when submitted to the most “aggregation‐prone” environment, corresponding to the isoelectric point and consequently to zero net charge, both peptides acquire their maximum flexibility, but Aβ(1‐40) has a definitely higher conformational mobility than Aβ(1‐28). The absence of a hydrophobic “tail,” which is the most mobile part of the molecule in Aβ(1‐40), is the element lacking in Aβ(1‐28) for obtaining a “fully aggregating” phenotype. Our results suggest that conformational flexibility, determined by both hydrophobicity and charge effect, is the main mechanistic determinant of aggregation propensity. Proteins 2005. © 2004 Wiley‐Liss, Inc.
Quaternary structure is critical for protein display on capsid‐like particles (CLPs): Efficient generation of hepatitis B virus CLPs presenting monomeric but not dimeric and tetrameric fluorescent proteins
Authors: Vogel Maren , Vorreiter Jolanta , Nassal Michael 
Published: November 2004

AbstractSelf‐organizing assemblies such as viral capsids may be used as symmetrical molecular platforms for the display of heterologous sequences, with applications ranging from vaccines to structural studies. The 183‐amino‐acid hepatitis B virus (HBV) core protein assembles spontaneously into icosahedral capsid‐like particles (CLPs). The most exposed, and most immunogenic, substructure on the CLPs is a small loop that connects two long antiparallel α‐helices which act as dimerization interface. Ninety (90) or 120 dimers multimerize into the capsid; the four‐helix bundles formed by the dimers protrude as spikes from the surface. We recently demonstrated that the entire enhanced green fluorescent protein (eGFP) can be inserted into this loop, yielding CLPs that natively displayed eGFP on their surface. The central location of the insertion site requires that any insert be fixed to the carrier via both termini, with corresponding restrictions regarding insert size and structure. eGFP obviously satisfied these criteria but, surprisingly, all attempts to produce CLPs with the isostructural red fluorescent proteins DsRed1, DsRed2, and HcRed failed. Suspecting their oligomerization tendency to be responsible, we generated fusions containing instead monomeric yellow, cyan, and red fluorescent proteins (mYFP, mCFP and mRFP1). This strongly increased the yields of YFP and CFP‐CLPs, and it allowed for the first time to efficiently generate red fluorescent CLPs. Hence insert quaternary structure is a highly critical factor for CLP assembly. These data have important implications for the rational design of self‐assembling fusion proteins. Proteins 2005. © 2004 Wiley‐Liss, Inc.
Tobacco use in schizophrenia: a study of cotinine concentrations in the saliva of patients and controls
Authors: Strand Jan-Erik , Nybäck Henrik 
Published: November 2004

AbstractNicotine has been proposed to provide anxiety relief, oral gratification and self-medication of psychotic symptoms in psychiatric patients. In order to investigate the relations between psychopathology and tobacco use we measured the concentration of cotinine, the major metabolite of nicotine, in the saliva of psychiatric patients and healthy volunteers. In a sample of 42 schizophrenic patients we correlated smoking status, cotinine levels, symptom profiles (PANSS), and neuroleptic side effects (Simpson–Angus). Despite reporting the same amount of cigarettes consumed per day the saliva concentration of cotinine was significantly higher in patients with schizophrenia than in the controls. There were no significant differences in clinical characteristics between smoking and non-smoking schizophrenic patients, but smokers tended to be on higher drug doses. High cotinine concentrations correlated significantly with the negative symptoms Passive withdrawal and Social avoidance. The results indicate that the schizophrenic patients smoke cigarettes more intensely than other patients and healthy subjects. The correlation between high cotinine levels and negative symptomatology may reflect an attempt by schizophrenic patients to overcome the emotional withdrawal and thus the results may lend support to a self-medication hypothesis.
The labor–machine dyad and its influence on mix flexibility
Authors: Karuppan Corinne M. , Ganster Daniel C. 
Published: November 2004

AbstractThe joint, mediating, and interactive effects of three elements of labor and machine flexibility on mix flexibility were tested empirically in a PCB assembly plant. Both subjective and objective data were collected. Some elements of labor and machine flexibility mediated the relationship between an emphasis on competitive priorities and mix flexibility. The interactive effects of machine and labor flexibility on mix flexibility confirmed prior findings that the pursuit of total flexibility is not desirable. For low levels of labor flexibility, increasing machine flexibility yields at the most a very moderate improvement in mix flexibility. When labor flexibility is high, increasing machine flexibility proves to be counter‐productive. These results may suggest that the traditional forms of labor flexibility need to evolve when technological capabilities are more fully exploited.
Temporary versus Permanent Youth Brain Drain: Economic Implications
Authors: Baláz Vladimír , Williams Allan M. , Kollár Daniel 
Published: November 2004

AbstractExisting high levels of temporary migration between Central and Eastern Europe and the European Union (EU) have highlighted a number of concerns relating to the eastern enlargement of the Union. While much of the debate has focused on the destinations, we use Slovakia as a case study to explore economic implications for the countries of origin of highly skilled migrants. First, the paper examines estimates of the scale of “youth brain migration”, comparing survey‐based and expert‐opinion estimates with our own estimate based on reconciling labour market and educational data. This identifies a substantial loss of graduate workers from the labour force through migration, accounting for a potentially significant proportion of Gross Domestic Product (GDP) growth. Second, we consider whether such migration will constitute “brain drain/overflow” or “brain circulation”: in other words will it be temporary or permanent? In some ways, however, this is a false dichotomy, for there are strong links between initial temporary migration and intended permanent migration, explored here through a survey of the motivations and social networks of returned migrants. Third, we address the ability of national states to intervene to mediate such losses. We generally concur with other commentators on the need for a multi‐scalar and multi‐functional approach, focusing especially on economic development. However, we are pessimistic about the likely speed of economic convergence and, moreover, argue that initial temporary migration (with implications for permanent migration) will continue to be driven by non‐economic goals.
Autoantibodies to REG, a beta‐cell regeneration factor, in diabetic patients
Authors: Shervani N. J. , Takasawa S. , Uchigata Y. , Akiyama T. , Nakagawa K. , Noguchi N. , Takada H. , Takahashi I. , Yamauchi A. , Ikeda T. , Iwamoto Y. , Nata K. , Okamoto H. 
Published: November 2004

AbstractBackground  Regenerating gene (Reg) product, Reg, acts as an autocrine/paracrine growth factor for beta‐cell regeneration. The presence of autoimmunity against REG may affect the operative of the regenerative mechanisms in beta cells of Type 1 and Type 2 diabetes patients. We screened sera from Type 1 and Type 2 diabetes subjects for anti‐REG autoantibodies, searched for correlations in the general characteristics of the subjects with the presence of anti‐REG autoimmunity, and tested the attenuation of REG‐induced beta‐cell proliferation by the autoanitibodies.Material and methods  We examined the occurrence of anti‐REG autoantibodies in patients’ sera (265 Type 1, 368 Type 2 diabetes patients, and 75 unrelated control subjects) by Western blot analysis, and evaluated inhibitory effects of the sera on REG‐stimulated beta‐cell proliferation by a 5′‐Bromo‐2′‐deoxyuridine (BrdU) incorporation assay in vitro.Results  Anti‐REG autoantibodies were found in 24·9% of Type 1, 14·9% of Type 2 and 2·7% of control subjects (P = 0·0004). There were significant differences between the autoantibody positive and negative groups in the duration of disease in the Type 1 subjects (P = 0·0035), and the age of onset in the Type 2 subjects (P = 0·0274). The patient sera containing anti‐REG autoantibodies significantly attenuated the BrdU incorporation by REG (35·6 ± 4·06% of the control), whereas the nondiabetic sera without anti‐REG autoantibodies scarcely reduced the incorporation (88·8 ± 5·10%).Conclusion  Anti‐REG autoantibodies, which retard beta‐cell proliferation in vitro, are found in some diabetic patients. Thus, autoimmunity to REG may be associated with the development/acceleration of diabetes in at least some patients.
Problem‐solving competency of nursing graduates
Authors: Uys Leana R. , Van Rhyn Lily L. , Gwele Nomthandaso S. , McInerney Patricia , Tanga Tobeka 
Published: November 2004

Aim.  This paper reports a study describing and evaluating the outcomes of problem‐based learning (PBL) programmes in nursing schools in South Africa in terms of the competence of graduates to solve problem in actual clinical settings, and comparing this competence with that of graduates from non‐PBL programmes.Background.  The nursing literature tends to equate problem‐solving with patient‐centred problems or the nursing process. However, it is also a skill used in managing the work role, working in a team and managing a health care unit. Problem‐solving refers to the process of selectively attending to information in a patient care setting. The investigation of problem‐solving in nursing is complicated by the complex relationships between different cognitive processes.Methods.  A qualitative evaluation study, descriptive and comparative in nature, was carried out. In‐depth interviews were held with graduates and their supervisors, asking them to identify problem‐solving incidents in which they had been involved. Template analysis style and Benner's interpretive approach were used to analyse the data.Findings.  The majority of the incidents described by the graduates (84%) were graded at the advanced beginner level or above. The majority of incidents at the novice level came from the non‐PBL group. ‘Using people skills’ and ‘being assertive’ were the two problem‐solving strategies most often used. The PBL group fared better than the non‐problem‐based group in the level of their problem‐solving ability.Conclusion.  The findings of this study suggest that further research is warranted into the problem‐solving abilities of PBL graduates, their personal development over time and at different stages of practice. In addition, it would be interesting to follow the development of their problem‐solving abilities over time.
Homozygous familial hypercholesterolaemia presenting with cutaneous xanthomas: Response to liver transplantation
Authors: Moyle Mignon , Tate Bruce 
Published: November 2004

SUMMARY A 19‐month‐old girl with cutaneous xanthomas was diagnosed with homozygous familial hypercholesterolaemia, treated with atorvastatin, plasma exchange and finally at the age of 3.5 years, with liver transplantation. Her serum cholesterol levels fell to normal and the xanthomas regressed following liver transplantation. She remains well 17 months post transplant.
Interaction of multiple disturbances: importance of disturbance interval in the effects of fire on rehabilitating mined areas
Authors: Ross Karen A. , Taylor Jennifer E. , Fox Marilyn D. , Fox Barry J. 
Published: November 2004

Abstract  Multiple disturbance regimes are increasingly common as novel anthropogenic disturbances are added to existing natural disturbances. However, it is generally unknown whether simultaneous or sequential effects of different forms of disturbance are predictable from the independent effects of each disturbance. This study examines the short‐term effects of sequential disturbance by mineral sand‐mining followed by fire in a forest community in south‐eastern Australia. Four combinations of disturbance were sampled: unburned mined, burned mined, unburned forest (unmined) and burned forest (unmined, with between‐fire interval matching the disturbance interval between mining and fire of the burned mined treatment). All combinations were sampled approximately 12 months following fire on the burned sites. The impact of fire after mining depended on disturbance interval. Sites burned 0.5–2.4 years since mining had fewer native vascular plant species than unburned mined sites of the same mined age, whereas sites with 10–16 years or 20–26 years between mining and fire had greater native species richness than unburned mined sites of the same age. Burning 20–26 years after mining brought native species richness within the range of burned forest. For both unmined and mined sites native seedling densities increased with burning, and with longer disturbance intervals. Weed species richness and weed seedling densities were greater on mined sites than in forest, and burning mined sites elevated weed seedling densities further, particularly for short intervals. Both disturbance interval and fire intensity are likely to have contributed to these results, as intensity on mined areas increased with interval, and at 20–26 years post‐mining was equivalent to unmined forest. These results suggest that fire could be used to promote rehabilitation of these mined areas after at least 10 years, but should be excluded from earlier stages of post‐mining regeneration. However, other sources of spatial and temporal variability should be considered in addition to interval and intensity, as variation among mined areas was correlated with post‐fire weather conditions and available weed sources. Finally, the combined effects of mining and fire could not be predicted from knowledge of the disturbances operating separately, indicating that effects of multiple disturbance may be synergistic rather than additive.