86 research outputs found
Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo
We use data from the second science run of the LIGO gravitational-wave
detectors to search for the gravitational waves from primordial black hole
(PBH) binary coalescence with component masses in the range 0.2--.
The analysis requires a signal to be found in the data from both LIGO
observatories, according to a set of coincidence criteria. No inspiral signals
were found. Assuming a spherical halo with core radius 5 kpc extending to 50
kpc containing non-spinning black holes with masses in the range 0.2--, we place an observational upper limit on the rate of PBH coalescence
of 63 per year per Milky Way halo (MWH) with 90% confidence.Comment: 7 pages, 4 figures, to be submitted to Phys. Rev.
Broad Epigenetic Signature of Maternal Care in the Brain of Adult Rats
BACKGROUND: Maternal care is associated with long-term effects on behavior and epigenetic programming of the NR3C1 (GLUCOCORTICOID RECEPTOR) gene in the hippocampus of both rats and humans. In the rat, these effects are reversed by cross-fostering, demonstrating that they are defined by epigenetic rather than genetic processes. However, epigenetic changes at a single gene promoter are unlikely to account for the range of outcomes and the persistent change in expression of hundreds of additional genes in adult rats in response to differences in maternal care. METHODOLOGY/PRINCIPAL FINDINGS: We examine here using high-density oligonucleotide array the state of DNA methylation, histone acetylation and gene expression in a 7 million base pair region of chromosome 18 containing the NR3C1 gene in the hippocampus of adult rats. Natural variations in maternal care are associated with coordinate epigenetic changes spanning over a hundred kilobase pairs. The adult offspring of high compared to low maternal care mothers show epigenetic changes in promoters, exons, and gene ends associated with higher transcriptional activity across many genes within the locus examined. Other genes in this region remain unchanged, indicating a clustered yet specific and patterned response. Interestingly, the chromosomal region containing the protocadherin-α, -β, and -γ (Pcdh) gene families implicated in synaptogenesis show the highest differential response to maternal care. CONCLUSIONS/SIGNIFICANCE: The results suggest for the first time that the epigenetic response to maternal care is coordinated in clusters across broad genomic areas. The data indicate that the epigenetic response to maternal care involves not only single candidate gene promoters but includes transcriptional and intragenic sequences, as well as those residing distantly from transcription start sites. These epigenetic and transcriptional profiles constitute the first tiling microarray data set exploring the relationship between epigenetic modifications and RNA expression in both protein coding and non-coding regions across a chromosomal locus in the mammalian brain
Concerning the vitamin D reference range: pre-analytical and analytical variability of vitamin D measurement
Unlike other vitamins, the vitamin D concentration in blood varies cyclically over the course of the year in relation to genetic (gender, ethnicity, polymorphisms) and environmental factors (sunlight exposure, diet, food-related or direct vitamin D supplementation, skin pigmentation). Although the major diagnostics manufacturers have recently developed improved automated 25-hydroxy vitamin D immunoassays, the intra- and interlaboratory variability is still high (especially at low vitamin D concentrations) which might lead to incorrect vitamin D deficiency/insufficiency diagnosis.
Moreover, despite recent efforts to standardize the assay and minimize its variability, the current bias for measured vitamin D concentrations
is often still above the desirable ± 10% criterion. Because the implications of low vitamin D concentrations in non-skeletal diseases are still partially unknown, international guideline recommendations for establishing meaningful ranges, at any time over the course of the year, irrespective not only of environmental and personal factors but also of instrumental variability, are needed. In this review, we discuss the main factors that influence the variability of vitamin D concentrations and whether a centile curve, individually calculated by a theoretical equation considering such factors, might be better suited than a fixed limit to assess abnormal vitamin D concentrations in otherwise healthy subjects. Vitamin D reference ranges during pregnancy, childhood, or diagnosed illnesses, which merit separate discussion, are beyond the scope of this review
Effects of obstetric factors and storage temperatures on the yield of endothelial colony forming cells from umbilical cord blood
Different Drivers: Exploring employee involvement in corporate philanthropy
Corporate Philanthropy (CP) is multi-dimensional, differs between sectors and involves both individual and organizational decision-making to achieve business and social goals. However, the CP literature characteristically focuses on strategic decisions made by business leaders and ignores the role of employees, especially those in lower status and lower paid positions. To redress this imbalance, we conducted a qualitative study of employees’ involvement in CP processes in ten workplaces in the South East of England to identify whether and how they are involved in CP decision-making and to capture their perspective on the nature of CP and the benefits generated by such activities. We specifically chose to study workplaces where employees are involved in the actual execution of the CP strategy, prioritising companies with a visible presence on the high street. The results illustrate the benefits of involving employees in CP decision-making, which we argue derives in part from the ‘liminal-like states’ that typify CP activities organised by shop floor staff, involving the temporary overturning of hierarchies, humanising of workplaces and opportunities for lower-level staff to prioritise their personal philanthropic preferences and signal their charitable identity to colleagues and customers. Whilst the data also suggests that CP decision-making remains predominantly top-down and driven by profit-oriented goals, we conclude that employees should be involved in choosing charitable causes as well as in designing and implementing workplace fundraising, in order to maximise the advantages of CP for the company and for wider society
Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study
Background
Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.
Methods
We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).
Findings
In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683–0·717]).
Interpretation
In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.
Funding
British Journal of Surgery Society
Eruptive dynamics of the 2021 Tajogaite eruption (La Palma, Canary Islands) as revealed by the physical and textural characterization of tephra
A multidisciplinary study of juvenile material ejected during the September–December 2021 eruption of Tajogaite volcano (La Palma, Canary Islands) was conducted to understand the processes that occurred during pre-eruptive magma ascent and within the conduit system, in order to obtain a reconstruction of the eruptive dynamics. Variations in the physical, morphological, textural, and chemical characteristics of the juvenile material reveal changes in the mechanisms of outgassing, fragmentation, and velocity of magma ascent within the conduits. In agreement with the three main identified eruptive phases, we found that Phase I corresponds to the maximum eruption intensity, when highly vesicular clasts were produced, which show primary vesicularity modes between 54.7 and 68.0% decreasing from the base to the top of the deposit of this phase and Nvm values between 1.6 and 46.3 × 106 cm−3. Morphological parameters show high solidity (a shape descriptor quantifying the complexity of the particle’s outer surface, with values close to 1 indicating a more equable shape), medium to low convexity (measuring surface irregularity, with lower values indicating rougher textures), and low axial ratios (the ratio of a particle’s dimensions, reflecting elongation), indicating the presence of clasts with predominantly irregular morphology and rough and spongy outer surfaces. Phase II was initially characterized by a lower eruptive intensity, producing dense juvenile material with irregular to subspherical morphologies, and afterwards by explosive activity characterized by intermittent episodes of variable intensity. Phase II clasts show vesicularity modes between 60.3 and 61.2% and Nvm values between 13.2 and 59.4 × 106 cm−3. Solidity values are high while convexity values cover a wider range indicating the presence of clasts with both smooth and rough external surfaces. Phase III was characterized by a new increase in eruptive intensity with clasts that show a vesicularity mode at ⁓60.2% and average Nvm values ranging from 8.5 to 85.8 × 106 cm−3. The morphology of the clasts is variable, while solidity and convexity values are higher than the other phases. Syn-eruptive variability confirmed the presence of multiple conduits simultaneously active and defined by different geometries that regulated the processes of outgassing, fragmentation, and crystallization of magma as it ascended to the surface. The tephra clasts are compositionally grouped in the tephrite-basanite field, showing increasingly more mafic compositions with eruption progression, with observed variations likely associated with repeated (more primitive) magmatic inputs that fuelled the eruption over time.</p
Identification and Structural Elucidation of Vitamin D3 Metabolites in Human Urine Using LC-MS-MS
Effect of depolarizing and hyperpolarizing agents on the membrane potential difference of primary cultures of rabbit aorta vascular smooth muscle cells
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