bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discordance between nuclear and mitochondrial genomes in sexual and asexual lineages of the freshwater snail Potamopyrgus antipodarum
Authors: Paczesniak Dorota , Jokela Jukka , Larkin Katelyn , Neiman Maurine 
Published: August 2013

AbstractThe presence and extent of mitonuclear discordance in coexisting sexual and asexual lineages provides insight into 1) how and when asexual lineages emerged, and 2) the spatial and temporal scales at which the ecological and evolutionary processes influencing the evolution of sexual and asexual reproduction occur. Here, we used nuclear single‐nucleotide polymorphism (SNP) markers and a mitochondrial gene to characterize phylogeographic structure and the extent of mitonuclear discordance in Potamopyrgus antipodarum. This New Zealand freshwater snail is often used to study the evolution and maintenance of sex because obligately sexual and obligately asexual individuals often coexist. While our data indicate that sexual and asexual P. antipodarum sampled from the same lake population are often genetically similar, suggesting recent origin of these asexuals from sympatric sexual P. antipodarum, we also found significantly more population structure in sexuals vs. asexuals. This latter result suggests that some asexual lineages originated in other lakes and/or in the relatively distant past. When comparing mitochondrial and nuclear population genetic structure, we discovered that one mitochondrial haplotype (‘1A’) was rare in sexuals, but common and widespread in asexuals. Haplotype 1A frequency and nuclear genetic diversity were not associated, suggesting that the commonness of this haplotype cannot be attributed entirely to genetic drift and pointing instead to a role for selection.
Local dynamics of a fast‐evolving sex‐ratio system in Drosophila simulans
Authors: Bastide Héloïse , Gérard Pierre R. , Ogereau David , Cazemajor Michel , Montchamp‐Moreau Catherine 
Published: August 2013

AbstractBy distorting Mendelian transmission to their own advantage, X‐linked meiotic drive elements can rapidly spread in natural populations, generating a sex‐ratio bias. One expected consequence is the triggering of a co‐evolutionary arms race between the sex chromosome that carries the distorter and suppressors counteracting its effect. Such an arms race has been theoretically and experimentally established and can have many evolutionary consequences. However, its dynamics in contemporary populations is still poorly documented. Here, we investigate the fate of the young X‐linked Paris driver in Drosophila simulans from sub‐Saharan Africa to the Middle East. We provide the first example of the early dynamics of distorters and suppressors: we find consistent evidence that the driving chromosomes have been rising in the Middle East during the last decade. In addition, identical haplotypes are at high frequencies around the two co‐evolving drive loci in remote populations, implying that the driving X chromosomes share a recent common ancestor and suggesting that East Africa could be the cradle of the Paris driver. The segmental duplication associated with drive presents an unusual structure in West Africa, which could reflect a secondary state of the driver. Together with our previous demonstration of driver decline in the Indian Ocean where suppression is complete, these data provide a unique picture of the complex dynamics of a co‐evolutionary arms race currently taking place in natural populations of D. simulans.
Low plant density enhances gene dispersal in the Amazonian understory herb Heliconia acuminata
Authors: Côrtes Marina C. , Uriarte María , Lemes Maristerra R. , Gribel Rogério , John Kress W. , Smouse Peter E. , Bruna Emilio M. 
Published: August 2013

AbstractIn theory, conservation genetics predicts that forest fragmentation will reduce gene dispersal, but in practice, genetic and ecological processes are also dependent on other population characteristics. We used Bayesian genetic analyses to characterize parentage and propagule dispersal in Heliconia acuminata L. C. Richard (Heliconiaceae), a common Amazonian understory plant that is pollinated and dispersed by birds. We studied these processes in two continuous forest sites and three 1‐ha fragments in Brazil's Biological Dynamics of Forest Fragments Project. These sites showed variation in the density of H. acuminata. Ten microsatellite markers were used to genotype flowering adults and seedling recruits and to quantify realized pollen and seed dispersal distances, immigration of propagules from outside populations, and reproductive dominance among parents. We tested whether gene dispersal is more dependent on fragmentation or density of reproductive plants. Low plant densities were associated with elevated immigration rates and greater propagule dispersal distances. Reproductive dominance among inside‐plot parents was higher for low‐density than for high‐density populations. Elevated local flower and fruit availability is probably leading to spatially more proximal bird foraging and propagule dispersal in areas with high density of reproductive plants. Nevertheless, genetic diversity, inbreeding coefficients and fine‐scale spatial genetic structure were similar across populations, despite differences in gene dispersal. This result may indicate that the opposing processes of longer dispersal events in low‐density populations vs. higher diversity of contributing parents in high‐density populations balance the resulting genetic outcomes and prevent genetic erosion in small populations and fragments.
On the Validation of Solids Represented with the International Standards for Geographic Information
Authors: Ledoux Hugo 
Published: August 2013

AbstractThe international standards for geographic information provide unambiguous definitions of geometric primitives, with the aim of fostering exchange and interoperability in the geographical information system (GIS) community. In two dimensions, the standards are well accepted and there are algorithms (and implementations of these) to validate primitives, that is given a polygon, they ensure that it respects the standardized definition (and if it does not a reason is given to the user). However, although there exists an equivalent definition in three dimensions (for solids), it is ignored by most researchers and by software vendors. Several different definitions are indeed used, and none is compliant with the standards: for example solids are often defined as two‐manifold objects only, although in fact they can be nonmanifold objects. Exchanging and converting data sets from one format/platform to another is thus highly problematic. I present in this article a methodology to validate solids according to the international standards. It is hierarchical and permits us to validate the primitives of all dimensionalities. To understand and study the topological relationships between the different parts of a solid (the shells) the concept of Nef polyhedron is used. The methodology has been implemented in a prototype, and I report on the main engineering decisions that were made and on its use for the validation of real‐world three‐dimensional data sets.
Associations between child temperament, maternal feeding practices and child body mass index during the preschool years: a systematic review of the literature
Authors: Bergmeier H. , Skouteris H. , Horwood S. , Hooley M. , Richardson B. 
Published: August 2013

SummaryIt is a research priority to identify modifiable risk factors to improve the effectiveness of childhood obesity prevention strategies. Research, however, has largely overlooked the role of child temperament and personality implicated in obesogenic risk factors such as maternal feeding and body mass index (BMI) of preschoolers. A systematic review of relevant literature was conducted to investigate the associations between child temperament, child personality, maternal feeding and BMI and/or weight gain in infants and preschoolers; 18 papers were included in the review. The findings revealed an association between the temperament traits of poor self‐regulation, distress to limitations, low and high soothability, low negative affectivity and higher BMI in infants and preschool‐aged children. Temperament traits difficult, distress to limitations, surgency/extraversion and emotionality were significantly associated with weight gain rates in infants. The results also suggested that child temperament was associated with maternal feeding behaviours that have been shown to influence childhood overweight and obesity, such as using restrictive feeding practices with children perceived as having poor self‐regulation and feeding potentially obesogenic food and drinks to infants who are more externalizing. Interestingly, no studies to date have evaluated the association between child personality and BMI/weight gain in infants and preschoolers. There is a clear need for further research into the association of child temperament and obesogenic risk factors in preschool‐aged children.
Economic evaluation of cell salvage in pediatric surgery
Authors: Samnaliev Mihail , Tran Chau M. , Sloan Steven R. , Gasior Izabela , Lightdale Jenifer R. , Brustowicz Robert M. 
Published: August 2013

AbstractBackgroundRed blood cells are a scarce resource with demand outstripping supply. Use of intraoperative red cell salvage (CS) – the process of collecting shed blood during surgery and reinfusing it to patients – is often used as an effective blood conservation strategy. However, little is known about the economic impact of CS during pediatric surgery.MethodsA decision tree model was used to estimate the transfusion‐related costs per patient (2010 USD) from a healthcare system perspective of four transfusion strategies among children undergoing elective orthopedic or cardiac surgery: (i) CS followed by allogeneic transfusion, (ii) CS followed by autologous transfusion, (iii) allogeneic transfusion alone, and (iv) autologous transfusion alone.ResultsCell salvage and allogeneic transfusion was the least expensive strategy (USD 883.3) followed by CS and autologous blood transfusion (USD 1,269.7), allogeneic transfusion alone (USD 1,443.0), and autologous transfusion alone (USD 1,824.7). Savings associated with CS use persisted in separate analyses of orthopedic and cardiac surgery, as well as in one‐way and probabilistic sensitivity analyses.ConclusionsUse of CS, particularly along with allogeneic blood transfusion, appears cost‐saving and cost‐effective in pediatric surgery.
Distinct styles of fluvial deposition in a Cambrian rift basin
Authors: Santos Maurício G. M. , Almeida Renato P. , Godinho Lucas P. S. , Marconato André , Mountney Nigel P. 
Published: August 2013

AbstractProcess‐based and facies models to account for the origin of pre‐vegetation (i.e. pre‐Silurian) preserved fluvial sedimentary architectures remain poorly defined in terms of their ability to account for the nature of the fluvial conditions required to accumulate and preserve architectural elements in the absence of the stabilizing influence of vegetation. In pre‐vegetation fluvial successions, the repeated reworking of bars and minor channels that resulted in the generation and preservation of broad, tabular, stacked sandstone‐sheets has been previously regarded as the dominant sedimentary mechanism. This situation is closely analogous to modern‐day poorly vegetated systems developed in arid climatic settings. However, this study demonstrates the widespread presence of substantially more complex stratigraphic architectures. The Guarda Velha Formation of Southern Brazil is a >500 m‐thick synrift fluvial succession of Cambrian age that records the deposits and sedimentary architecture of three distinct fluvial successions: (i) an early rift‐stage system characterized by coarse‐grained channel elements indicative of a distributive pattern with flow transverse to the basin axis; and two coeval systems from the early‐ to climax‐rift stages that represent (ii) an axially directed, trunk fluvial system characterized by large‐scale amalgamated sandy braid‐bar elements, and (iii) a distributive fluvial system characterized by multi‐storey, sandy braided‐channel elements that flowed transverse to the basin axis. Integration of facies and architectural‐element analysis with regional stratigraphic basin analysis, palaeocurrent and pebble‐provenance analysis demonstrates the mechanisms responsible for preserving the varied range of fluvial architectures present in this pre‐vegetation, rift‐basin setting. Identified major controls that influenced pre‐vegetation fluvial sedimentary style include: (i) spatial and temporal variation in discharge regime; (ii) the varying sedimentological characteristics of distinct catchment areas; (iii) the role of tectonic basin configuration and its direct role in influencing palaeoflow direction and fluvial style, whereby both the axial and transverse fluvial systems undertook a distinctive response to syn‐depositional movement on basin‐bounding faults. Detailed architectural analyses of these deposits reveal significant variations in geometry, with characteristics considerably more complex than that of simple, laterally extensive, stacked sandstone‐sheets predicted by most existing depositional models for pre‐vegetation fluvial systems. These results suggest that the sheet‐braided style actually encompasses a varied number of different pre‐vegetation fluvial styles. Moreover, this study demonstrates that contemporaneous axial and transverse fluvial systems with distinctive architectural expressions can be preserved in the same overall tectonic and climatic setting.
HBcAg‐Specific IL‐21‐Producing CD4+ T Cells are Associated with Relative Viral Control in Patients with Chronic Hepatitis B
Authors: Li L. , Liu M. , Cheng L.‐W. , Gao X.‐Y. , Fu J.‐J. , Kong G. , Feng X. , Pan X.‐C. 
Published: August 2013

AbstractFunction exhaustion of specific cytotoxic CD8+ T cell in chronic virus infection partly results from the low levels of CD4 help, but the mechanisms by which CD4 help T cell required to control hepatitis B virus infection are not well understood. In this study, we investigated the role of interleukin‐21‐producing CD4+ T cell response in viral control of hepatitis B virus infection. HBcAg‐specific interleukin‐21‐producing CD4+ T cells in blood were detected in patients with hepatitis B virus infection. Patients with acute hepatitis B had greater HBcAg‐specific interleukin‐21‐producing CD4+ T cells in blood compared with chronic hepatitis B patients, and there was no statistical significance between immune active chronic hepatitis B patients and inactive healthy carrier patients for these cells, whereas frequencies of these cells negatively correlated with HBV DNA levels but positively correlated with HBc18‐27‐specific IFN‐γ‐producing CD8+ T cells. Moreover, interleukin‐21 sustained HBc18‐27‐specific CD8+ T cells in vitro, and interleukin‐21 production by HBcAg‐specific IL‐21‐producing CD4+ T cells of acute hepatitis B patients enhanced IFN‐γ and perforin expression by CD8+ T cells from chronic hepatitis B patients. Our results demonstrate that HBcAg‐specific interleukin‐21‐producing CD4+ T cell responses might contribute to viral control by sustaining CD8+ T cell antiviral function.
A Controlled Study of Suicide in Middle‐Aged and Older People: Personality Traits, Age, and Psychiatric Disorders
Authors: Draper Brian , Kõlves Kairi , De Leo Diego , Snowdon John 
Published: August 2013

Personality traits were examined using the NEO Five‐Factor Inventory–Revised in an Australian psychological autopsy study involving 259 suicide deaths and 181 sudden death controls aged 35 years and over. Interviews included the Structured Clinical Interview for DSM‐IV to determine the presence of psychiatric disorder. Personality traits of suicide deaths differed significantly from those of controls, scoring higher in the Neuroticism and Openness to Experience domains and lower on the Agreeableness and Extraversion domains. These findings varied with the presence of psychiatric disorder and by age. High Neuroticism scores were the most consistent finding in people who died by suicide, although these scores decreased in older suicides.
Ideas and Norms in Swedish Peace Policy
Authors: Björkdahl Annika 
Published: August 2013

AbstractChallenging conventional wisdom that powerful states do as they will and small states do as they must, this article advances an analysis of small states and the role they can play as agents of change in the area of peace and security. Insights from constructivist research on foreign policy contribute to explain why some small states adopt norm entrepreneurship as a diplomatic strategy and how such strategy helps small states punch above their weight in international relations. The article is based on an in‐depth case study of Sweden as a norm entrepreneur promoting the norm pertaining to the prevention of violent conflicts in the EU and UN, and it assesses the impact of the following strategies used by such a norm entrepreneur: norm construction, agenda‐shaping, coalition‐building, and support of institutionalisation.
PCR Slippage Across the ML‐2 Microsatellite of the Cryptosporidium MIC1 Locus Enables Development of a PCR Assay Capable of Distinguishing the Zoonotic Cryptosporidium parvum From Other Human Infectious Cryptosporidium Species
Authors: Webber M. A. , Sari I. , Hoefel D. , Monis P. T. , King B. J. 
Published: August 2013

SummaryCryptosporidium are ubiquitous and significant enteropathogens of all classes of vertebrates and a major cause of human morbidity and mortality worldwide. Of the 24 recognized species, the zoonotic Cryptosporidium parvum and the host‐specific Cryptosporidium hominis cause the majority of cases of human cryptosporidiosis. Here, we report on structural and transcriptional variability between C. parvum and C. hominis at the MIC1 locus, which encodes a microneme localized thrombospondin‐like domain containing protein previously demonstrated to be critical for host cell infection by C. parvum. We demonstrate, using reverse transcription quantitative PCR with the aid of genomic data from the EuPathDB site, that the transcribed product in C. hominis is both truncated and significantly down‐regulated in the sporozoite. We hypothesize that CpMIC1 may be a genetic factor involved in facilitating the wider host range of C. parvum in comparison with the specific host range of C. hominis. Furthermore, we show that the presence of a microsatellite (ML‐2) within the C. parvum MIC‐1 locus enables the development of a PCR marker that can rapidly distinguish the zoonotic C. parvum from C. hominis and other significant human infectious Cryptosporidium species due to reproducible PCR slippage across the ML‐2 microsatellite. Additionally, we demonstrate that this locus is tightly linked to the GP60 locus, a locus commonly used in the genetic characterization of C. parvum and C. hominis isolates. This marker should provide a robust and additional tool to aid in the rapid identification of C. parvum from other Cryptosporidium species.
Use of genetic models of idiopathic hypogonadotrophic hypogonadism in mice and men to understand the mechanisms of disease
Authors: Lippincott Margaret F. , True Cadence , Seminara Stephanie B. 
Published: August 2013

New findings
What is the topic of this review?This review discusses the genetics of idiopathic hypogonadotrophic hypogonadism, with a focus on how deficiencies in the kisspeptin and neurokinin B pathways result in reproductive dysfunction in both mice and men.
What advances does it highlight?In humans, deficiencies in kisspeptin signalling lead to a sustained absence of puberty. Mutations in the neurokinin B pathway are also associated with an initial absence of pubertal development, but the hypogonadotrophism can improve later in life with spontaneous activation of the hypothalamic–pituitary–gonadal cascade. Mouse models with mutations in each of these pathways recapitulate many of the features observed in human patients. Spontaneous recovery of gonadotrophin‐releasing hormone secretion, termed ‘reversal’, indicates that the hypothalamic–pituitary–gonadal axis may be capable of awakening in the setting of neurokinin B signalling abnormalities.
Mutations in the genes encoding the neuropeptides kisspeptin and neurokinin B, as well as their receptors, are associated with gonadotrophin‐releasing hormone (GnRH) deficiency and a failure to initiate and/or progress through puberty. Although the total number of patients studied to date is small, mutations in the kisspeptin pathway appear to result in lifelong GnRH deficiency. Mice with mutations in kisspeptin and the kisspeptin receptor, Kiss1−/− and Kiss1r−/−, respectively, appear to be phenocopies of the human with abnormal sexual maturation and infertility. In contrast, mutations in the neurokinin B pathway lead to a more variable adult reproductive phenotype, with a subset of hypogonadotrophic individuals demonstrating paradoxical recovery of reproductive function later in life. While ‘reversal’ remains poorly understood, the ability to recover reproductive function indicates that neurokinin B may play different roles in the initiation of sexual maturation compared with the maintenance of adult reproductive function. Mice with mutations in the gene encoding the neurokinin B receptor, Tacr3, have abnormal oestrous cycles and subfertility but, similar to their human counterparts, appear less severely affected than mice with kisspeptin deficiency. Further investigations into the interaction between the kisspeptin and neurokinin B pathways will reveal key insights into how GnRH neuronal modulation occurs at puberty and throughout reproductive life.