1,255 research outputs found
MHC class IIa haplotypes derived by high-throughput SNP screening in an isolated sheep population
RAD-sequencing for estimating GRM-based heritability in the wild:a case study in roe deer
International audienceEstimating the evolutionary potential of quantitative traits and reliably predicting responses to selection in wild populations are important challenges in evolutionary biology. The genomic revolution has opened up opportunities for measuring relatedness among individuals with precision, enabling pedigree‐free estimation of trait heritabilities in wild populations. However, until now, most quantitative genetic studies based on a genomic relatedness matrix (GRM) have focused on long‐term monitored populations for which traditional pedigrees were also available, and have often had access to knowledge of genome sequence and variability. Here, we investigated the potential of RAD‐sequencing for estimating heritability in a free‐ranging roe deer (Capreolous capreolus) population for which no prior genomic resources were available. We propose a step‐by‐step analytical framework to optimize the quality and quantity of the genomic data and explore the impact of the single nucleotide polymorphism (SNP) calling and filtering processes on the GRM structure and GRMbased heritability estimates. As expected, our results show that sequence coverage strongly affects the number of recovered loci, the genotyping error rate and the amount of missing data. Ultimately, this had little effect on heritability estimates and their standard errors, provided that the GRM was built from a minimum number of loci (above 7,000). Genomic relatedness matrix‐based heritability estimates thus appear robust to a moderate level of genotyping errors in the SNP data set. We also showed that quality filters, such as the removal of low‐frequency variants, affect the relatedness structure of the GRM, generating lower h2 estimates. Our work illustrates the huge potential of RAD‐sequencing for estimating GRM‐based heritability in virtually any natural population
Estimating the functional form for the density dependence from life history data
Two contrasting approaches to the analysis of population dynamics are currently popular: demographic approaches where the associations between demographic rates and statistics summarizing the population dynamics are identified; and time series approaches where the associations between population dynamics, population density, and environmental covariates are investigated. In this paper, we develop an approach to combine these methods and apply it to detailed data from Soay sheep (Ovis aries). We examine how density dependence and climate contribute to fluctuations in population size via age- and sex-specific demographic rates, and how fluctuations in demographic structure influence population dynamics. Density dependence contributes most, followed by climatic variation, age structure fluctuations and interactions between density and climate. We then simplify the density-dependent, stochastic, age-structured demographic model and derive a new phenomenological time series which captures the dynamics better than previously selected functions. The simple method we develop has potential to provide substantial insight into the relative contributions of population and individual-level processes to the dynamics of populations in stochastic environments
Obstetricians and Violence against Women
I argue that the American Congress of Obstetricians and Gynecologists (ACOG), as an organization and through its individual members, can and should be a far greater ally in the prevention of violence against women. Specifically, I argue that we need to pay attention to obstetrical practices that inadvertently contribute to the problem of violence against women. While intimate partner violence is a complex phenomenon, I focus on the coercive control of women and adherence to oppressive gender norms. Using physician response to alcohol use during pregnancy and court-ordered medical treatment as examples, I show how some obstetrical practices mirror the attitudes of abusive men insofar as they try to coercively control women\u27s behavior through manipulation and violence. To be greater allies in the prevention of violence against women, obstetricians should stop participating in practices that inadvertently perpetuate violence against women
Poly-use of cannabis and other substances among juvenile-justice involved youth: variations in psychological and substance-related problems by typology
Background:
Adolescent cannabis use is associated with increased risk for psychological problems, with evidence for more severe problems among youth who use cannabis in combination with other substances (i.e., polysubstance use). Juvenile offenders engage in both cannabis use and polysubstance use at higher rates than the general adolescent population. Yet, limited research has examined the relationship between cannabis poly-use (e.g., cannabis and alcohol use) and functional or psychological problems among juvenile offenders.
Objectives:
The current study addresses this gap by examining the association of polysubstance use of cannabis compared to cannabis only use with cognitive functioning, psychological distress, and substance-related problems among juvenile detainees.
Methods:
Participants were 238 detained youth ages 12–18 (80.4% male, 77.3% non-White) who completed assessments of substance use, intellectual functioning, psychological symptoms, and substance-related problems. Youth were also assessed by a clinical psychologist for substance use disorder.
Results:
Four cannabis-use typologies were identified; cannabis and alcohol use was the largest class, followed by cannabis only use, cannabis, alcohol and other drug use, then cannabis and other drug use. Polysubstance use was associated with lower scores on measures of intellectual functioning, more externalizing and internalizing symptomology, and more substance-related problems relative to cannabis only use. However, the relationship between polysubstance use and problems varied by typology.
Conclusions:
Findings suggest that justice-involved youth engaged in polysubstance use may be at greater need for concurrent academic, affective, and behavioral support in their rehabilitation and transition back to the community
Selective Regulation of Cytoskeletal Dynamics and Filopodia Formation by Teleost Leukocyte Immune-Type Receptors Differentially Contributes to Target Capture During the Phagocytic Process
Phagocytosis evolved from a fundamental nutrient acquisition mechanism in primitive unicellular amoeboids, into a dynamic and complex component of innate immunity in multicellular organisms. To better understand the cellular mechanisms contributing to phagocytic processes across vertebrates, our research has focused on characterizing the involvement of innate immune proteins originally identified in channel catfish (Ictalurus punctatus) called leukocyte immune-type receptors (IpLITRs). These unique teleost proteins share basic structural as well as distant phylogenetic relationships with several immunoregulatory proteins within the mammalian immunoglobulin superfamily. In the present study, we use a combination of live-cell confocal imaging and high-resolution scanning electron microscopy to further examine the classical immunoreceptor tyrosine-based activation motif (ITAM)-dependent phagocytic pathway mediated by the chimeric construct IpLITR 2.6b/IpFcRγ-L and the functionally diverse immunoreceptor tyrosine-based inhibitory motif-containing receptor IpLITR 1.1b. Results demonstrate that IpLITR 1.1b-expressing cells can uniquely generate actin-dense filopodia-like protrusions during the early stages of extracellular target interactions. In addition, we observed that these structures retract after contacting extracellular targets to secure captured microspheres on the cell surface. This activity was often followed by the generation of robust secondary waves of actin polymerization leading to the formation of stabilized phagocytic cups. At depressed temperatures of 27°C, IpLITR 2.6b/IpFcRγ-L-mediated phagocytosis was completely blocked, whereas IpLITR 1.1b-expressing cells continued to generate dynamic actin-dense filopodia at this lower temperature. Overall, these results provide new support for the hypothesis that IpLITR 1.1b, but not IpLITR 2.6b/IpFcRγ-L, directly triggers filopodia formation when expressed in representative myeloid cells. This also offers new information regarding the directed ability of immunoregulatory receptor-types to initiate dynamic membrane structures and provides insights into an alternative ITAM-independent target capture pathway that is functionally distinct from the classical phagocytic pathways
Associations between MHC class II variation and phenotypic traits in a free-living sheep population
Introduction of new guest molecules into BEDT-TTF radical-cation salts with tris(oxalato)ferrate
Radical-cation salts of formula β′′-(BEDT-TTF)4[(H3O)Fe(C2O4)3]·guest have produced a large number of superconductors and provided a route to introduce magnetism and chirality into the same multifunctional material. A relationship has been found in these salts between the length of the b axis and the superconducting Tc. Increasing the b axis length by introducing larger guest molecules, such as benzonitrile and nitrobenzene, gives the highest superconducting Tcs in this family of salts. Smaller guests such as pyridine show no superconducting transition, whilst asymmetrical guests which are larger than nitrobenzene have given a different bilayered structure. Other potential guest molecules have been limited by their ability to be used as the solvent in which the crystals are grown via electrocrystallisation. This paper reports a method which introduces guest molecules into the crystal which are a solid or liquid additive within the crystal-growing solvent 1,2,4-trichlorobenzene:ethanol. We present the crystal structures of five new BEDT-TTF radical-cation salts with tris(oxalato)ferrate anions using guest molecules toluene, phenol, benzaldehyde, 4-bromobenzaldehyde, and kojic acid
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