bluuebunny/crossref_metadata_2025_split huggingface dataset:
Behavioural structuring of relatedness in the spotted hyena (Crocuta crocuta) suggests direct fitness benefits of clan‐level cooperation
Authors: Van Horn Russell C. , Engh Anne L. , Scribner Kim T. , Funk Stephan M. , Holekamp Kay E. 
Published: January 2004

AbstractSpotted hyenas (Crocuta crocuta) are gregarious carnivores that live in multigenerational social groups, called clans, containing one to several matrilines. Members of multiple matrilines within a clan cooperate during dangerous interactions with inter‐ and intraspecific competitors. The evolution of cooperation may be influenced by relatedness between individuals, which in turn is influenced by reproductive skew and mate choice, dispersal and territorial behaviours. Behavioural data exist for spotted hyenas, but corresponding data on patterns of relatedness are unavailable; this lack of data makes it difficult to assess the relative importance of selection pressures favouring cooperative behaviour within and among groups. Therefore we conducted a longitudinal analysis of relatedness within a single large clan of spotted hyenas, as well as a cross‐sectional analysis of relatedness among hyenas from multiple clans. Within a clan, patterns of relatedness reflected known pedigree relationships, and relatedness was higher within than among matrilines, even across generations. Although mean within‐matriline relatedness varied among matrilines, it did not decline with matriline rank. On average, clan members were not related closely, due to high levels of male‐mediated gene flow among clans, and relatedness declined very slightly across clan borders. Low mean relatedness within clans suggests that spotted hyenas cooperate with unrelated clan‐mates against close paternal kin in other clans. Our data also suggest that spotted hyenas must derive large net direct fitness benefits from group living and cooperation.
Phylogeography, genetic structure and diversity in the endangered bearded vulture (Gypaetus barbatus, L.) as revealed by mitochondrial DNA
Authors: Godoy José A. , Negro Juan J. , Hiraldo Fernando , Donázar José A. 
Published: January 2004

AbstractBearded vulture populations in the Western Palearctic have experienced a severe decline during the last two centuries that has led to the near extinction of the species in Europe. In this study we analyse the sequence variation at the mitochondrial control region throughout the species range to infer its recent evolutionary history and to evaluate the current genetic status of the species. This study became possible through the extensive use of museum specimens to study populations now extinct. Phylogenetic analysis revealed the existence of two divergent mitochondrial lineages, lineage A occurring mainly in Western European populations and lineage B in African, Eastern European and Central Asian populations. The relative frequencies of haplotypes belonging to each lineage in the different populations show a steep East–West clinal distribution with maximal mixture of the two lineages in the Alps and Greece populations. A genealogical signature for population growth was found for lineage B, but not for lineage A; futhermore the Clade B haplotypes in western populations and clade A haplo‐types in eastern populations are recently derived, as revealed by their peripheral location in median‐joining haplotype networks. This phylogeographical pattern suggests allopatric differentiation of the two lineages in separate Mediterranean and African or Asian glacial refugia, followed by range expansion from the latter leading to two secondary contact suture zones in Central Europe and North Africa. High levels of among‐population differentiation were observed, although these were not correlated with geographical distance. Due to the marked genetic structure, extinction of Central European populations in the last century re‐sulted in the loss of a major portion of the genetic diversity of the species. We also found direct evidence for the effect of drift altering the genetic composition of the remnant Pyrenean population after the demographic bottleneck of the last century. Our results argue for the management of the species as a single population, given the apparent ecological exchangeability of extant stocks, and support the ongoing reintroduction of mixed ancestry birds in the Alps and planned reintroductions in Southern Spain.
Postglacial colonization shows evidence for sympatric population splitting of Eurasian perch (Perca fluviatilis L.) in Lake Constance
Authors: Behrmann‐Godel J. , Gerlach G. , Eckmann R. 
Published: January 2004

AbstractPrevious microsatellite analysis showed that two subpopulations of perch (Perca fluviatilis L.) exist in Lake Constance. This raises questions of whether (i) Lake Constance was colonized by two populations that diverged in allopatry, or (ii) the two subpopulations diverged in sympatry. Sequence analysis of a 365 bp mtDNA fragment (5′‐end of the D‐loop) of perch from Lake Constance and adjacent waters revealed 10 haplotypes. We suggest colonization via the Danube river, based on the frequency and dispersion of haplotypes, and knowledge of the lake's palaeohydrological development. Pairwise FST‐values using mitochondrial DNA sequences showed no significant population subdivision. Our study provides strong evidence that subpopulations of perch in Lake Constance have diverged in sympatry.
The population genetics of a biological control introduction: mitochondrial DNA and microsatellie variation in native and introduced populations ofAphidus ervi, a parisitoid wasp
Authors: Hufbauer R. A. , Bogdanowicz S. M. , Harrison R. G. 
Published: January 2004

AbstractIntroductions of biological control agents may cause bottlenecks in population size despite efforts to avoid them. We examined the population genetics of Aphidius ervi (Hymenoptera: Braconidae), a parasitoid that was introduced to North America from Western Europe in 1959 to control pea aphids. To explore the phylogeographical relationships of A. ervi we sequenced 1249 bp of mitochondrial DNA (mtDNA) from 27 individuals from the native range and 51 individuals from the introduced range. Most individuals from Western Europe, the Middle East and North America shared one of two common haplotypes, consistent with the known history of the introduction. However, some A. ervi from the Pacific Northwest have a haplotype that is most similar to haplotypes found in Japan, raising the possibility of a second accidental introduction. To examine population structure and assess whether a bottleneck occurred upon introduction to North America, we assayed variation at 5 microsatellite loci in 62 individuals from 2 native populations and 230 individuals from 6 introduced populations. Introduced samples had fewer rare alleles than native samples (F1,34 = 13.5, P = 0.0008), but heterozygosity did not differ significantly. These results suggest that a mild bottleneck occurred in spite of the introduction of over 1000 individuals. Using a hierarchical Bayesian approach, the founding population size was estimated to be 245 individuals. amova showed significant genetic differentiation between the European and North American samples, and a Bayesian assignment approach clustered individuals into four groups, with most European individuals in one group and most North American individuals in the other three. These results highlight that genetic changes are associated with founder events in rapidly growing natural populations, even when the founding population size is relatively large.
Current and historical patterns of drainage connectivity in eastern Australia inferred from population genetic structuring in a widespread freshwater fish Pseudomugil signifer (Pseudomugilidae)
Authors: Wong B. B. M. , Keogh J. S. , McGlashan D. J. 
Published: January 2004

AbstractDispersal can play an important role in the genetic structuring of natural populations. In this regard, freshwater fishes often exhibit extensive population genetic subdivision and are ideal subjects for investigating current and historical patterns of connection and dissociation between drainages. We set out to generate a comprehensive molecular phylogeny for a widespread freshwater fish from eastern Australia, the Pacific blue‐eye Pseudomugil signifer. Although movement via flood events may be important in the southern end of the species’ range, genetic structuring revealed the importance of historical drainage connections and dissociations in mediating or disrupting dispersal. A dominant feature of our phylogeny is a split between northern and southern populations, which appears to be congruent with a biogeographical barrier recently implicated as important for the connectivity of freshwater organisms in eastern Australia. The extent of the split also has taxonomic implications consistent with suggestions that the Pacific blue‐eye may represent more than a single species.
Phylogeography of the common goby, Pomatoschistus microps, with particular emphasis on the colonization of the Mediterranean and the North Sea
Authors: Gysels E. S. , Hellemans B. , Pampoulie C. , Volckaert F. A. M. 
Published: January 2004

AbstractThe phylogeographical patterns of a small marine fish, the common goby, Pomatoschistus microps, were assessed at 12 sites along the northeastern Atlantic coasts and the western Mediterranean Sea. A combination of two genetic markers was employed: cellulose acetate allozyme electrophoresis (CAGE) and sequence analysis of a 289 bp fragment of the mitochondrial locus cytochrome b. Both markers were congruent in revealing significant differences between samples (global FST = 0.247 for the allozymes and ΦST = 0.437 for the mitochondrial DNA data) and a pattern of isolation‐by‐distance. Phylogeographical analyses yielded a shallow branching structure with four groups. Three of those were confined to the Atlantic basin and showed a star‐like pattern. The fourth group contained a central haplotype occurring at the edges of the species’ distribution, accompanied by a few more rare variants, which were restricted to the Mediterranean Sea. A genetic break was observed around the British Isles, with distinct haplotypes dominating at either side of the English Channel. A significantly negative correlation between the degree of genetic diversity and latitude was recorded both for mitochondrial DNA (mtDNA) and allozymes in the Atlantic basin. Gene flow analysis suggested that recolonization of the North Sea and the coasts of western Scotland and Ireland may have taken place from a glacial refugium in the Southern Bight of the North Sea. These results are discussed in the perspective of possible postglacial migration routes of marine fish along the northeastern Atlantic coasts.
Founding events influence genetic population structure of sockeye salmon (Oncorhynchus nerka) in Lake Clark, Alaska
Authors: Ramstad K. M. , Woody C. A. , Sage G. K. , Allendorf F. W. 
Published: January 2004

AbstractBottlenecks can have lasting effects on genetic population structure that obscure patterns of contemporary gene flow and drift. Sockeye salmon are vulnerable to bottleneck effects because they are a highly structured species with excellent colonizing abilities and often occupy geologically young habitats. We describe genetic divergence among and genetic variation within spawning populations of sockeye salmon throughout the Lake Clark area of Alaska. Fin tissue was collected from sockeye salmon representing 15 spawning populations of Lake Clark, Six‐mile Lake, and Lake Iliamna. Allele frequencies differed significantly at 11 microsatellite loci in 96 of 105 pairwise population comparisons. Pairwise estimates of FST ranged from zero to 0.089. Six‐mile Lake and Lake Clark populations have historically been grouped together for management purposes and are geographically proximate. However, Six‐mile Lake populations are genetically similar to Lake Iliamna populations and are divergent from Lake Clark populations. The reduced allelic diversity and strong divergence of Lake Clark populations relative to Six‐mile Lake and Lake Iliamna populations suggest a bottleneck associated with the colonization of Lake Clark by sockeye salmon. Geographic distance and spawning habitat differences apparently do not contribute to isolation and divergence among populations. However, temporal isolation based on spawning time and founder effects associated with ongoing glacial retreat and colonization of new spawning habitats contribute to the genetic population structure of Lake Clark sockeye salmon. Nonequilibrium conditions and the strong influence of genetic drift caution against using estimates of divergence to estimate gene flow among populations of Lake Clark sockeye salmon.
Colony genetic organization and colony fusion in the termiteReticulitermes flavipesas revealed by foraging patterns over time and space
Authors: Deheer Christopher J. , Vargo Edward L. 
Published: January 2004

AbstractTemporal and spatial analyses are seldom utilized in the study of colony genetic structure, but they are potentially powerful methods which can yield novel insights into the mechanisms underlying variation in breeding systems. Here we present the results of a study which incorporated both of these dimensions in an examination of genetic structure of subterranean termites in the genusReticulitermes (primarilyR. flavipes). Most colonies of this species (70%) were simple families apparently headed by outbred primary reproductives, while most of the remaining (27% of the total) colonies contained low effective numbers of moderately inbred reproductives. Mapping the spatial distribution of colony foraging sites over time revealed that despite the high colony density, the absolute foraging boundaries of mostR. flavipescolonies were persistent and exclusive of other conspecific colonies, which suggests that this species is more territorial than has been implied by laboratory studies of intraspecific aggression. Nevertheless, we found a single colony (3% of all colonies) which contained the offspring of more than two unrelated reproductives. Although other studies have also described subterranean termite colonies with a similarly complex genetic composition, we demonstrate here that such colonies can form under natural conditions via the fusion of whole colonies. This study underscores how repeated sampling from individual colonies over time and space can yield information about colony spatial and genetic structure that cannot be obtained from conventional analyses or sampling methods.
Effects of the ACE Inhibitor Quinapril on Echocardiographic Variables in Horses with Mitral Valve Insufficiency
Authors: Gehlen H. , Vieht J. C. , Stadler P. 
Published: January 2004

SummaryTwenty horses with mitral valve insufficiency, but without signs of congestive heart failure, and five horses without signs of heart disease were examined before and after medication with an angiotensin‐converting enzyme (ACE) inhibitor. The examination included echocardiography assessment as well as heart catheterization. The echocardiographic examination included B‐mode, M‐mode, conventional and colour Doppler techniques. For 8 weeks, all horses were treated with Accupro 20®(active substance: Quinapril) at an oral dose rate of 120 mg/horse/day. A follow‐up of the horses with mitral valve insufficiency after 8 weeks revealed a statistically significant increase in the stroke volume and the cardiac output as well as a decrease in regurgitation velocity time integral (VTI). The regurgitation blood velocity remained the same. The severity of mitral valve insufficiencies revealed a moderate improvement in five horses, from moderate to mild, after therapy. Significant changes of cardiac dimension (B‐mode) and shortening fraction (M‐mode) before and after treatment could not be observed. The owners’ judgement of the horses’ performance was that of a minor improvement. In the horses without clinical findings the results of examination before and after treatment remained the same.
The future of the cuffed endotracheal tube
Authors: Fine Gavin F. , Borland Lawrence M. 
Published: January 2004

SummaryIt has been traditionally taught that only uncuffed endotracheal tubes (ETTs) should be used for intubation in children younger than 8, or even 10, years old. However, recent literature suggests that the advantages of using uncuffed ETTs in children may be just another myth of paediatric anaesthesia. Using an uncuffed ETT does allow a tube of larger internal diameter to be used, minimizing resistance to airflow and the work of breathing in the patient who is breathing spontaneously. However, this advantage does not hold for ventilated patients, for whom ventilator settings can be adjusted to provide optimal airflow. Longer duration of intubation and a poorly fitted ETT are risk factors for mucosal damage, whether the ETT is cuffed or uncuffed. Furthermore, a properly sized, positioned, and inflated modern (low‐pressure, high‐volume) cuffed ETT can offer many advantages over an uncuffed ETT, including greater ease of intubation, better control of air leakage, lower rate and better control of flow of anaesthetic gases, and decreased risk of aspiration and infection.
Meta‐Analysis of Linkage Studies for Complex Diseases: An Overview of Methods and a Simulation Study
Authors: Dempfle A. , Loesgen S. 
Published: January 2004

SummaryLinkage genome scans for complex diseases have low power with the usual sample sizes, and hence meta‐analysis of several scans for the same disease might be a promising approach. Appropriate data are now becoming accessible. Here we give an overview of the available statistical methods and current applications. In a simulation study, we compare the power of different methods to combine multipoint linkage scores, namely Fisher's p‐value combination, the truncated product method, the Genome Search Meta‐Analysis (GSMA) method and our weighting methods. In particular, we investigate the effects of heterogeneity introduced by different genetic marker sets and sample sizes between genome scans. The weighting methods explicitly take those differences into account and have more power in the simulated scenarios than the other methods.
On the Power of Affected Relative Pair Designs for Linkage Studies
Authors: LI Z. , GASTWIRTH J. L. 
Published: January 2004

SummaryUsing the recurrence risk ratio (λ), Risch (1990b) indicated that affected pairs of distant relatives are preferable to affected sib‐pairs for linkage analysis when λ is large and the mode of inheritance is additive. By using the optimum test for affected sib‐pairs instead of the test used by Risch (1990b), the range of values of λ for which the affected sib‐pair design has larger or smaller power than other pairs is clarified. Risch's conclusion remains true when λO > 2.5, however, sib‐pairs have larger power for lower values. As affected sib‐pairs occur smore frequently than other relative pairs, when ascertainment costs are non‐negligible, they may be the most cost‐effective relative pairs to use.
Crystal structure of human dipeptidyl peptidase IV in complex with a decapeptide reveals details on substrate specificity and tetrahedral intermediate formation
Authors: Aertgeerts Kathleen , Ye Sheng , Tennant Mike G. , Kraus Michelle L. , Rogers Joe , Sang Bi‐Ching , Skene Robert J. , Webb David R. , Prasad G. Sridhar 
Published: January 2004

AbstractDipeptidyl peptidase IV (DPPIV) is a member of the prolyl oligopeptidase family of serine proteases. DPPIV removes dipeptides from the N terminus of substrates, including many chemokines, neuropeptides, and peptide hormones. Specific inhibition of DPPIV is being investigated in human trials for the treatment of type II diabetes. To understand better the molecular determinants that underlie enzyme catalysis and substrate specificity, we report the crystal structures of DPPIV in the free form and in complex with the first 10 residues of the physiological substrate, Neuropeptide Y (residues 1–10; tNPY). The crystal structure of the free form of the enzyme reveals two potential channels through which substrates could access the active site—a so‐called propeller opening, and side opening. The crystal structure of the DPPIV/tNPY complex suggests that bioactive peptides utilize the side opening unique to DPPIV to access the active site. Other structural features in the active site such as the presence of a Glu motif, a well‐defined hydrophobic S1 subsite, and minimal long‐range interactions explain the substrate recognition and binding properties of DPPIV. Moreover, in the DPPIV/tNPY complex structure, the peptide is not cleaved but trapped in a tetrahedral intermediate that occurs during catalysis. Conformational changes of S630 and H740 between DPPIV in its free form and in complex with tNPY were observed and contribute to the stabilization of the tetrahedral intermediate. Our results facilitate the design of potent, selective small molecule inhibitors of DPPIV that may yield compounds for the development of novel drugs to treat type II diabetes.
Research Review: Risk and protection in the context of services for children in need
Authors: Little Michael , Axford Nick , Morpeth Louise 
Published: January 2004

ABSTRACTThe paper summarizes the evidence and provides definitions of risk, protective factors, resilience, coping strategies and need in the context of children in need. Definitions are offered for children in need and children's services. The way in which individual interpretation can alter objective assessment of risk is explored. A method for recording evidence relevant to clinical practice on behalf of children in need is offered. Implications for policy and practice are discussed.
The effectiveness of selected interventions for previous maltreatment: enhancing the well‐being of children who live at home
Authors: Dufour Sarah , Chamberland Claire 
Published: January 2004

ABSTRACTThe authors critically assessed reviews of the literature published between 1984 and 2002 to describe the state‐of‐knowledge about the effectiveness of interventions aimed at protecting or improving the welfare of child victims of maltreatment and who remain in the family home. The interventions studied target children, parents or families. They chiefly involve cases of sexual abuse, physical abuse or neglect; very few concern psychological abuse or exposure to violence. For the most part, the intervention effectiveness indicators measure changes in parents’ and children's knowledge (e.g. better knowledge of child development), attitude (e.g. gains in enthusiasm), emotion (e.g. decreased anxiety) and behaviour (e.g. decreased rates of aversive behaviours). Few assessments follow up on participants to determine whether the changes are lasting. The small number of evaluative studies, methodological limitations and disparities in the content and the carrying out of interventions make it difficult to draw sound conclusions about the effectiveness of interventions, even for interventions most often and most favourably assessed, such as behavioural and cognitive‐behavioural interventions with maltreating parents. Implications for practice, research and policy are underlined.