128 research outputs found
Eclipsing white dwarf binaries in Gaia and the Zwicky Transient Faaccility
Gaia provided the largest ever catalogue of white dwarf stars. We use this catalogue, along with the third public data release of the Zwicky Transient Facility (ZTF), to identify new eclipsing white dwarf binaries. Our method exploits light-curve statistics and the box least-squares algorithm to detect periodic light-curve variability. The search revealed 18 new binaries, of which 17 are eclipsing. We use the position in the Gaia H-R diagram to classify these binaries and find that the majority of these white dwarfs have MS companions. We identify one system as a candidate eclipsing white dwarfâbrown dwarf binary and a further two as extremely low-mass white dwarf binaries. We also provide identification spectroscopy for 17 of our 18 binaries. Running our search method on mock light curves with real ZTF sampling, we estimate our efficiency of detecting objects with light curves similar to the ones of the newly discovered binaries. Many more binaries are to be found in the ZTF footprint as the data releases grow, so our survey is ongoing
Intrauterine devices and endometrial cancer risk : a pooled analysis of the Epidemiology of Endometrial Cancer Consortium
Intrauterine devices (IUDs), long-acting and reversible contraceptives, induce a number of immunological and biochemical changes in the uterine environment that could affect endometrial cancer (EC) risk. We addressed this relationship through a pooled analysis of data collected in the Epidemiology of Endometrial Cancer Consortium. We combined individual-level data from 4 cohort and 14 case-control studies, in total 8,801 EC cases and 15,357 controls. Using multivariable logistic regression, we estimated pooled odds ratios (pooled-ORs) and 95% confidence intervals (CIs) for EC risk associated with ever use, type of device, ages at first and last use, duration of use and time since last use, stratified by study and adjusted for confounders. Ever use of IUDs was inversely related to EC risk (pooled-ORâ=â0.81, 95% CIâ=â0.74-0.90). Compared with never use, reduced risk of EC was observed for inert IUDs (pooled-ORâ=â0.69, 95% CIâ=â0.58-0.82), older age at first use (â„35 years pooled-ORâ=â0.53, 95% CIâ=â0.43-0.67), older age at last use (â„45 years pooled-ORâ=â0.60, 95% CIâ=â0.50-0.72), longer duration of use (â„10 years pooled-ORâ=â0.61, 95% CIâ=â0.52-0.71) and recent use (within 1 year of study entry pooled-ORâ=â0.39, 95% CIâ=â0.30-0.49). Future studies are needed to assess the respective roles of detection biases and biologic effects related to foreign body responses in the endometrium, heavier bleeding (and increased clearance of carcinogenic cells) and localized hormonal changes
Frequency of exacerbations in patients with chronic obstructive pulmonary disease: an analysis of the SPIROMICS cohort
Background Present treatment strategies to stratify exacerbation risk in patients with chronic obstructive pulmonary disease (COPD) rely on a history of two or more events in the previous year. We aimed to understand year to year variability in exacerbations and factors associated with consistent exacerbations over time. Methods In this longitudinal, prospective analysis of exacerbations in the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) cohort, we analysed patients aged 40â80 years with COPD for whom 3 years of prospective data were available, identified through various means including care at academic and non-academic medical centres, word of mouth, and existing patient registries. Participants were enrolled in the study between Nov 12, 2010, and July 31, 2015. We classified patients according to yearly exacerbation frequency: no exacerbations in any year; one exacerbation in every year during 3 years of follow-up; and those with inconsistent exacerbations (individuals who had both years with exacerbations and years without during the 3 years of follow-up). Participants were characterised by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) spirometric category (1â4) on the basis of post-bronchodilator FEV1. Stepwise logistic regression was used to compare factors associated with one or more acute exacerbations of COPD every year for 3 years versus no exacerbations in the same timeframe. Additionally, a stepwise zero-inflated negative binomial model was used to assess predictors of exacerbation count during follow-up in all patients with available data. Baseline symptom burden was assessed with the COPD assessment test. This trial is registered with ClinicalTrials.gov, number NCT01969344. Findings 2981 patients were enrolled during the study. 1843 patients had COPD, of which 1105 patients had 3 years of complete, prospective follow-up data. 538 (49%) of 1105 patients had at least one acute exacerbation during the 3 years of follow-up, whereas 567 (51%) had none. 82 (7%) of 1105 patients had at least one acute exacerbation each year, whereas only 23 (2%) had two or more acute exacerbations in each year. An inconsistent pattern (both years with and without acute exacerbations) was common (456 [41%] of the group), particularly among GOLD stages 3 and 4 patients (256 [56%] of 456). In logistic regression, consistent acute exacerbations (â„1 event per year for 3 years) were associated with higher baseline symptom burden, previous exacerbations, greater evidence of small airway abnormality on CT, lower interleukin-15 concentrations, and higher interleukin-8 concentrations, than were no acute exacerbations. Interpretation Although acute exacerbations are common, the exacerbation status of most individuals varies markedly from year to year. Among patients who had any acute exacerbation over 3 years, very few repeatedly had two or more events per year. In addition to symptoms and history of exacerbations in the year before study enrolment, we identified several novel biomarkers associated with consistent exacerbations, including CT-defined small airway abnormality, and interleukin-15 and interleukin-8 concentrations. Funding National Institutes of Health, and National Heart, Lung, and Blood Institute
Epizootic mortality in the pilchard Sardinops sagax neopilchardus in Australia and New Zealand in 1995. II. Identification of a herpesvirus within the gill epithelium
Mass mortalities, among pilchards Sardinops sagax neopilchardus occurred around Australia and New Zealand from March to September 1995 The mortalities spread rapidly both with and against currents and usually affected fish longer than 11 cm. Examination showed mortalities to be associated with the presence of replicating herpesvirus in the gill epithelium; herpesviruses were not observed within equivalent cells of unaffected fish collected ahead of the mortality front By negative contrast ele ctron microscopy the virus was demonstrated to possess a 96 nm icosahedral capsid containing 162 capsomers. Many virions were enveloped and possessed surface projections. The nuclei of infected epithelial cells contained nuclcoids, capsids and nucleocapsids which were released from the nucleus into the surrounding cytoplasm following degeneration of the nuclear membrane. Within the cytoplasm, the capsids and nucleocapsids acquired a tegument and subsequently were enveloped by passing into smooth-surfaced vesicles or by budding from the plasma membrane. Release of viruses from the cells was in the main, associated with lysis of infected gill epithelial cells. The morphology of the virus and ultrastructure of infected cells suggest that this virus belongs to the family Herpesviridae. The presence of a replicating herpesvirus within the gill epithelium is discussed in context with the epizootic
- âŠ