1,482 research outputs found
Two-photon correlations as a sign of sharp transition in quark-gluon plasma
The photon production arising due to time variation of the medium has been
considered. The Hamilton formalism for photons in time-variable medium (plasma)
has been developed with application to inclusive photon production. The results
have been used for calculation of the photon production in the course of
transition from quark-gluon phase to hadronic phase in relativistic heavy ion
collisions. The relative strength of the effect as well as specific two- photon
correlations have been evaluated. It has been demonstrated that the opposite
side two-photon correlations are indicative of the sharp transition from the
quark-gluon phase to hadrons.Comment: 23 pages, 2 figure
The (pseudo)issue of the conformal frame revisited
The issue of the equivalence between Jordan and Einstein conformal frames in
scalar-tensor gravity is revisited, with emphasis on implementing running units
in the latter. The lack of affine parametrization for timelike worldlines and
the cosmological constant problem in the Einstein frame are clarified, and a
paradox in the literature about cosmological singularities appearing only in
one frame is solved. While, classically, the two conformal frames are
physically equivalent, they seem to be inequivalent at the quantum level.Comment: 29 pages, latex, to appear in Phys. Rev.
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Altitude and life-history shape the evolution of Heliconius wings.
Phenotypic divergence between closely related species has long interested biologists. Taxa that inhabit a range of environments and have diverse natural histories can help understand how selection drives phenotypic divergence. In butterflies, wing color patterns have been extensively studied but diversity in wing shape and size is less well understood. Here, we assess the relative importance of phylogenetic relatedness, natural history, and habitat on shaping wing morphology in a large dataset of over 3500 individuals, representing 13 Heliconius species from across the Neotropics. We find that both larval and adult behavioral ecology correlate with patterns of wing sexual dimorphism and adult size. Species with solitary larvae have larger adult males, in contrast to gregarious Heliconius species, and indeed most Lepidoptera, where females are larger. Species in the pupal-mating clade are smaller than those in the adult-mating clade. Interestingly, we find that high-altitude species tend to have rounder wings and, in one of the two major Heliconius clades, are also bigger than their lowland relatives. Furthermore, within two widespread species, we find that high-altitude populations also have rounder wings. Thus, we reveal novel adaptive wing morphological divergence among Heliconius species beyond that imposed by natural selection on aposematic wing coloration
Effect of Metformin on the High-Density Lipoprotein Proteome in Youth with Type 1 Diabetes
Background: Youth with type 1 diabetes (T1D) have normal or elevated High-Density Lipoprotein Cholesterol (HDL-C), however, the function of HDL, partly mediated by the HDL proteome, may be impaired. Metformin can be used as an adjunct therapy in youth with T1D, but its effects on the HDL proteome are unknown.
Objective: To determine the effect of metformin on the HDL proteome.
Subjects: Youth (12-20 years old) with T1D who had a BMI \u3e 90th percentile, HbA1c \u3e 8.0% and Tanner stage 5.
Methods: Double-blinded, placebo-controlled randomized sub-study. We examined the effects of metformin (n = 25) or placebo (n = 10) after 6 months on HDL proteome. Changes in HDL proteins were measured by data-independent acquisition (DIA) mass spectrometry and compared between treatment groups. As a secondary outcome, associations between proteins of interest and the most studied function of HDL, the cholesterol efflux capacity (CEC), was examined.
Results: The relative abundance of 84 HDL-associated proteins were measured. Two proteins were significantly affected by metformin treatment, peptidoglycan recognition protein 2 (PGRP2; +23.4%, p = .0058) and alpha-2-macroglobulin (A2MG; +29.8%, p = .049). Metformin did not significantly affect CEC. Changes in affected HDL proteins did not correlate with CEC.
Conclusions: Despite having little effect on HDL-C, metformin increased PGRP2 and A2MG protein on HDL in youth with T1D, but had no significant effect on CEC. Further studies are needed to understand the impact of PGRP2 and A2MG on other HDL functions
Toward a Unified Genetic Map of Higher Plants, Transcending the Monocot-Dicot Divergence
Closely related (confamilial) genera often retain large chromosomal tracts in which gene order is colinear, punctuated by structural mutations such as inversions and translocations 1. To explore the possibility that conservation of gene order might extrapolate to more distantly related taxa, we first estimated an average structural mutation rate. Nine pairs of taxa, for which there exist both comparative genetic maps and plausible estimates of divergence time, showed an average of0.14 (±0.06) structural mutations per chromosome per million years of divergence (Myr; Table 1). This value is offered as a first approximation, acknowledging that refined comparative data and/or divergence estimates may impel revision
The Role of Gender in Nurse-Resident Interactions: A mixed-methods study
Background: Gender disparities continue to persist within the medical field. Adverse effects of gender bias are well documented, including among trainees in Emergency Medicine (EM). The extent to which gender bias affects interprofessional interactions is not well understood.
Objectives: The study aimed to understand perceptions and experiences of gender bias in interactions between emergency medicine (EM) residents and emergency department (ED) nurses.
Methods: This mixed-methods study involved eight key informant interviews and two focus groups, and an anonymous electronic survey administered to EM residents and nurses at two teaching hospitals. Quantitative analysis included descriptive statistics and between-group comparisons using Student t-tests and two-sample Wilcoxon rank-sum. Qualitative analysis used a inductive and thematic content analysis.
Results: Most participants identified gender as an important factor in ED interprofessional relationships. Key themes emerging from qualitative data include differential treatment and communication styles based on gender. 134 individuals completed the survey: 104 nurses (29% response rate), 30 residents (53% response rate). Females more frequently reported experiencing interprofessional gender bias than males [mean 30.9 (95% CI 25.6-36.2) vs 17.6 (95%CI 10.3-24.9)]. Residents of both genders reported witnessing interprofessional gender bias more frequently than nurses [mean 58.7 (95%CI 48.6-68.7) vs 23.9 (95%CI 19.4-28.4)]. Residents, compared to nurses, more frequently felt gender bias affects job satisfaction (p=0.002) and patient care (p=0.001). These differences were largely driven by female residents’ responses.
Conclusion/impact: Gender plays a significant role in shaping interprofessional interactions in the ED. Gender bias in interprofessional interactions contributes to workplace dissatisfaction, particularly for female residents. Initiatives to establish equitable relationships across the gender spectrum in EM are needed to address interprofessional gender bias.https://jdc.jefferson.edu/sexandgenderhealth/1033/thumbnail.jp
Limited genetic parallels underlie convergent evolution of quantitative pattern variation in mimetic butterflies
Mimetic systems allow us to address the question of whether the same genes control similar phenotypes in different species. Although widespread parallels have been found for major effect loci, much less is known about genes that control quantitative trait variation. In this study, we identify and compare the loci that control subtle changes in the size and shape of forewing pattern elements in twoHeliconiusbutterfly co-mimics. We use quantitative trait locus (QTL) analysis with a multivariate phenotyping approach to map the variation in red pattern elements across the whole forewing surface ofHeliconius eratoandHeliconius melpomene. These results are compared with a QTL analysis of univariate trait changes, and show that our resolution for identifying small effect loci is somewhat improved with the multivariate approach, but also that different loci are detected with these different approaches. QTL likely corresponding to the known patterning geneoptixwere found in both species but otherwise, a remarkably low level of genetic parallelism was found. This lack of similarity indicates that the genetic basis of convergent traits may not be as predictable as assumed from studies that focus solely on Mendelian traits.Peer reviewe
Insulin resistance in type 1 diabetes: what is ‘double diabetes’ and what are the risks?
In this review, we explore the concept of ‘double diabetes’, a combination of type 1 diabetes with features of insulin resistance and type 2 diabetes. After considering whether double diabetes is a useful concept, we discuss potential mechanisms of increased insulin resistance in type 1 diabetes before examining the extent to which double diabetes might increase the risk of cardiovascular disease (CVD). We then go on to consider the proposal that weight gain from intensive insulin regimens may be associated with increased CV risk factors in some patients with type 1 diabetes, and explore the complex relationships between weight gain, insulin resistance, glycaemic control and CV outcome. Important comparisons and contrasts between type 1 diabetes and type 2 diabetes are highlighted in terms of hepatic fat, fat partitioning and lipid profile, and how these may differ between type 1 diabetic patients with and without double diabetes. In so doing, we hope this work will stimulate much-needed research in this area and an improvement in clinical practice
In-situ characterization of the Hamamatsu R5912-HQE photomultiplier tubes used in the DEAP-3600 experiment
The Hamamatsu R5912-HQE photomultiplier-tube (PMT) is a novel high-quantum
efficiency PMT. It is currently used in the DEAP-3600 dark matter detector and
is of significant interest for future dark matter and neutrino experiments
where high signal yields are needed.
We report on the methods developed for in-situ characterization and
monitoring of DEAP's 255 R5912-HQE PMTs. This includes a detailed discussion of
typical measured single-photoelectron charge distributions, correlated noise
(afterpulsing), dark noise, double, and late pulsing characteristics. The
characterization is performed during the detector commissioning phase using
laser light injected through a light diffusing sphere and during normal
detector operation using LED light injected through optical fibres
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