179 research outputs found
Light Curve Analysis of Hipparcos Data for the Massive O-type Eclipsing Binary UW CMa
Hipparcos photometric data for the massive O-type binary UW CMa were analysed
within the framework of the Roche model. Photometric solutions were obtained
for five mass ratios in the range. The system is found to
be in a contact configuration. Independently of , the best-fitting model
solutions correspond to the orbital inclination and the
temperature of the secondary component , at the fixed
temperature of the primary . Considering that the spectrum of the
secondary is very weak, photometric solutions corresponding to the contact
configuration favor the mass ratio smaller than unity (in which case the
luminosity of the secondary is smaller than that of the primary). The absolute
parameters of the system are estimated for different values of the mass ratio.Comment: 18 pages, 6 figure
Short-term exposure to air pollution and incidence of stroke in the Women's Health Initiative
Background: Evidence of the association between daily variation in air pollution and risk of stroke is inconsistent, potentially due to the heterogeneity in stroke etiology. Objectives: To estimate the associations between daily variation in ambient air pollution and risk of stroke and its subtypes among participants of the Women's Health Initiative, a large prospective cohort study in the United States. Methods: We used national-scale, log-normal ordinary kriging models to estimate daily concentrations of fine particulate matter (PM2.5), respirable particulate matter (PM10), nitrogen dioxide (NO2), nitrogen oxides (NOx), sulphur dioxide, and ozone at participant addresses. Stroke was adjudicated by trained neurologists and classified as ischemic or hemorrhagic. Ischemic strokes were further classified according to the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification. We used a time-stratified case-crossover approach to estimate the odds ratio (OR) of the risk of stroke associated with an interquartile range (IQR) increase in concentrations of each air pollutant. We performed stratified analysis to examine whether associations varied across subgroups defined by age at stroke onset, US census region, smoking status, body mass index, and prior history of diabetes mellitus, hypertension, heart or circulation problems, or arterial fibrillation at enrollment. Results: Among 5417 confirmed strokes between 1993 and 2012, 4300 (79.4%) were classified as ischemic and 924 (17.1%) as hemorrhagic. No association was observed between day-to-day variation in any pollutant and risk of total stroke, ischemic stroke, or specific etiologies of ischemic stroke. We observed a positive association between risk of hemorrhagic stroke and NO2 and NOx in the 3 days prior to stroke with OR of 1.24 (95% CI: 1.01, 1.52) and 1.18 (95% CI: 1.03, 1.34) per IQR increase, respectively. The observed associations with hemorrhagic stroke were more pronounced among non-obese participants. Conclusions: In this large cohort of post-menopausal US women, daily NO2 and NOx were associated with higher risk of hemorrhagic stroke, but ambient levels of four other air pollutants were not associated with higher risk of total stroke, ischemic stroke, or ischemic stroke subtypes
Long-term exposure to ambient particulate matter and stroke etiology: Results from the Women's Health Initiative
Background: Ambient particulate matter (PM) air pollution is a leading cause of global disability and accounts for an annual 2.9 million deaths globally. PM is established as an important risk factor for cardiovascular disease, however the evidence supporting a link specifically between long-term exposure to ambient PM and incident stroke is less clear. We sought to evaluate the association of long-term exposure to different size fractions of ambient PM with incident stroke (overall and by etiologic subtypes) and cerebrovascular deaths within the Women's Health Initiative, a large prospective study of older women in the US. Methods: We studied 155,410 postmenopausal women without previous cerebrovascular disease enrolled into the study between 1993 and 1998, with follow-up through 2010. We assessed geocoded participant address-specific concentrations of ambient PM (fine [PM2.5], respirable [PM10] and coarse [PM10-2.5]), as well as nitrogen dioxide [NO2] using spatiotemporal models. We classified hospitalization events into ischemic, hemorrhagic, or other/unclassified stroke. Cerebrovascular mortality was defined as death from any stroke etiology. We used Cox proportional hazard models to calculate hazard ratios (HR) and 95% confidence intervals (CI), adjusting for individual and neighborhood-level characteristics. Results: During a median follow-up time of 15 years, participants experienced 4,556 cerebrovascular events. The hazard ratio for all cerebrovascular events was 2.14 (95% CI: 1.87, 2.44) comparing the top versus bottom quartiles of PM2.5. Similarly, there was a statistically significant increase in events comparing the top versus bottom quartiles of PM10 and NO2 (HR: 1.17; 95% CI: 1.03, 1.33 and HR:1.26; 95% CI: 1.12, 1.42). The strength of association did not vary substantially by stroke etiology. There was little evidence of an association between PMcoarse and incident cerebrovascular events. Conclusions: Long-term exposure to fine (PM2.5) and respirable (PM10) particulate matter as well as NO2 was associated with a significant increase of cerebrovascular events among postmenopausal women. Strength of the associations were consistent by stroke etiology
Teores de aminoácidos e fenóis em plântulas de algodoeiro (Gossypium hirsutum L. cv. 'IAC-17') sob ação de reguladores vegetais
This research deals with the effects of exogenous growth regulators on dry weight, contents of aminoacids and phenolic compounds in leaves of cotton plants. To study the influence of the chemicals, cotton seeds were immersed during 22 hours in water solutions of (2-chloroethyl) trimethylammonium chloride (CCC) at concentration of 2000 ppm, succinic acid-2,2-dimethylhydrazide 4000 ppm,gibberellic acid 100 ppm, indolylacetic acid (IAA) 100 ppm, and water as check treatment. CCC 2000 ppm increased the dry weight in the leaves of cotton plants. This growth retardant increased the content of free aminoacids in cotton leaves. IAA 100 ppm reduced the concentration of aminoacids in the treated plants. The contents of phenolic compounds in leaves of cotton was increased by CCC, in relation to check treatment.Verificaram-se os efeitos da aplicação de reguladores de crescimento na porcentagem de materia seca, aminoácidos livres totais e compostos fenólicos nas folhas de algodoeiro 'lAC-l7'. Para se estudar a ação dos fitoreguladores, sementes de algodoeiro foram imersas durante 22 horas em soluções aquosas de cloreto (2-cloroetil) trimetilamônio (CCC) na concentração de 2000 ppm, ácido succínico-2,2-dimetilhidrazida 4000 ppm, ácido giberélico 100 ppm, ácido indolilacético (IAA) 100 ppm e água como controle. Plântulas com 33 dias de idade foram coletadas, sendo em seguida realizada a amostragem de folhas em laboratório, para efetuar-se a extração dos compostos. Observou-se que CCC 2000 ppm promoveu aumento no peso seco das folhas de algodoeiro. Esse retardador de crescimento aumentou o conteúdo de aminoácidos livres totais nas folhas estudadas. IAA 100 ppm reduziu a concentração de aminoácidos, nas plantas tratadas. O teor de fenóis totais nas folhas de Gossypium hirsutum foi aumentado por efeito do CCC com relação ao controle
Contributions of the Women's Health Initiative to Cardiovascular Research: JACC State-of-the-Art Review
The WHI (Women's Health Initiative) enrolled 161,808 racially and ethnically diverse postmenopausal women, ages 50-79 years, from 1993 to 1998 at 40 clinical centers across the United States. In its clinical trial component, WHI evaluated 3 randomized interventions (menopausal hormone therapy; diet modification; and calcium/vitamin D supplementation) for the primary prevention of major chronic diseases, including cardiovascular disease, in older women. In the WHI observational study, numerous clinical, behavioral, and social factors have been evaluated as predictors of incident chronic disease and mortality. Although the original interventions have been completed, the WHI data and biomarker resources continue to be leveraged and expanded through ancillary studies to yield novel insights regarding cardiovascular disease prevention and healthy aging in women
Supplemental Association of Clonal Hematopoiesis With Incident Heart Failure
Background: Age-related clonal hematopoiesis of indeterminate potential (CHIP), defined as clonally expanded leukemogenic sequence variations (particularly in DNMT3A, TET2, ASXL1, and JAK2) in asymptomatic individuals, is associated with cardiovascular events, including recurrent heart failure (HF). Objectives: This study sought to evaluate whether CHIP is associated with incident HF. Methods: CHIP status was obtained from whole exome or genome sequencing of blood DNA in participants without prevalent HF or hematological malignancy from 5 cohorts. Cox proportional hazards models were performed within each cohort, adjusting for demographic and clinical risk factors, followed by fixed-effect meta-analyses. Large CHIP clones (defined as variant allele frequency >10%), HF with or without baseline coronary heart disease, and left ventricular ejection fraction were evaluated in secondary analyses. Results: Of 56,597 individuals (59% women, mean age 58 years at baseline), 3,406 (6%) had CHIP, and 4,694 developed HF (8.3%) over up to 20 years of follow-up. CHIP was prospectively associated with a 25% increased risk of HF in meta-analysis (hazard ratio: 1.25; 95% confidence interval: 1.13-1.38) with consistent associations across cohorts. ASXL1, TET2, and JAK2 sequence variations were each associated with an increased risk of HF, whereas DNMT3A sequence variations were not associated with HF. Secondary analyses suggested large CHIP was associated with a greater risk of HF (hazard ratio: 1.29; 95% confidence interval: 1.15-1.44), and the associations for CHIP on HF with and without prior coronary heart disease were homogenous. ASXL1 sequence variations were associated with reduced left ventricular ejection fraction. Conclusions: CHIP, particularly sequence variations in ASXL1, TET2, and JAK2, represents a new risk factor for HF
Youth representations of environmental protest
A necessary condition for a functioning democracy is the participation of its citizens, including its youth. This is particularly true for political participation in environmental decisions because these decisions can have intergenerational consequences. In this article we examine young people’s beliefs about one form of political participation - protest - in the context of communities affected by fracking and associated anti-fracking protest, and discuss the implications of these representations for education. Drawing on focus groups with 121 young people (age 15-19) in 5 schools and colleges near sites which have experienced anti-fracking protest in England and Northern Ireland, we find young people well-informed about avenues for formal and non-formal political participation against a background of disillusionment with formal political processes and varying levels of support for protest. We find representations of protest as disruptive, divisive, extreme, less desirable than other forms of participation, and ineffective in bringing about change but effective in awareness-raising. These representations are challenging, not least because the way protest is interpreted is critical to the way people think and act in the world. These representations of environmental protest must be challenged through formal education in order to safeguard the UN Convention on the Rights of the Child and ensure that the spirit of Article 11 of the UK Human Rights Act is protected
The Public Repository of Xenografts enables discovery and randomized phase II-like trials in mice
More than 90% of drugs with preclinical activity fail in human trials, largely due to insufficient efficacy. We hypothesized that adequately powered trials of patient-derived xenografts (PDX) in mice could efficiently define therapeutic activity across heterogeneous tumors. To address this hypothesis, we established a large, publicly available repository of well-characterized leukemia and lymphoma PDXs that undergo orthotopic engraftment, called the Public Repository of Xenografts (PRoXe). PRoXe includes all de-identified information relevant to the primary specimens and the PDXs derived from them. Using this repository, we demonstrate that large studies of acute leukemia PDXs that mimic human randomized clinical trials can characterize drug efficacy and generate transcriptional, functional, and proteomic biomarkers in both treatment-naive and relapsed/refractory disease
DNAm-based signatures of accelerated aging and mortality in blood are associated with low renal function
Background: The difference between an individual's chronological and DNA methylation predicted age (DNAmAge), termed DNAmAge acceleration (DNAmAA), can capture life-long environmental exposures and age-related physiological changes reflected in methylation status. Several studies have linked DNAmAA to morbidity and mortality, yet its relationship with kidney function has not been assessed. We evaluated the associations between seven DNAm aging and lifespan predictors (as well as GrimAge components) and five kidney traits (estimated glomerular filtration rate [eGFR], urine albumin-to-creatinine ratio [uACR], serum urate, microalbuminuria and chronic kidney disease [CKD]) in up to 9688 European, African American and Hispanic/Latino individuals from seven population-based studies. Results: We identified 23 significant associations in our large trans-ethnic meta-analysis (p < 1.43E−03 and consistent direction of effect across studies). Age acceleration measured by the Extrinsic and PhenoAge estimators, as well as Zhang’s 10-CpG epigenetic mortality risk score (MRS), were associated with all parameters of poor kidney health (lower eGFR, prevalent CKD, higher uACR, microalbuminuria and higher serum urate). Six of these associations were independently observed in European and African American populations. MRS in particular was consistently associated with eGFR (β = − 0.12, 95% CI = [− 0.16, − 0.08] change in log-transformed eGFR per unit increase in MRS, p = 4.39E−08), prevalent CKD (odds ratio (OR) = 1.78 [1.47, 2.16], p = 2.71E-09) and higher serum urate levels (β = 0.12 [0.07, 0.16], p = 2.08E−06). The “first-generation” clocks (Hannum, Horvath) and GrimAge showed different patterns of association with the kidney traits. Three of the DNAm-estimated components of GrimAge, namely adrenomedullin, plasminogen-activation inhibition 1 and pack years, were positively associated with higher uACR, serum urate and microalbuminuria. Conclusion: DNAmAge acceleration and DNAm mortality predictors estimated in whole blood were associated with multiple kidney traits, including eGFR and CKD, in this multi-ethnic study. Epigenetic biomarkers which reflect the systemic effects of age-related mechanisms such as immunosenescence, inflammaging and oxidative stress may have important mechanistic or prognostic roles in kidney disease. Our study highlights new findings linking kidney disease to biological aging, and opportunities warranting future investigation into DNA methylation biomarkers for prognostic or risk stratification in kidney disease
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