213 research outputs found
A Bayesian Framework for Reliability Analysis of Spacecraft Deployments
Deployable subsystems are essential to mission success of most spacecraft. These subsystems enable critical functions including power, communications and thermal control. The loss of any of these functions will generally result in loss of the mission. These subsystems and their components often consist of unique designs and applications for which various standardized data sources are not applicable for estimating reliability and for assessing risks. In this study, a two stage sequential Bayesian framework for reliability estimation of spacecraft deployment was developed for this purpose. This process was then applied to the James Webb Space Telescope (JWST) Sunshield subsystem, a unique design intended for thermal control of the Optical Telescope Element. Initially, detailed studies of NASA deployment history, "heritage information", were conducted, extending over 45 years of spacecraft launches. This information was then coupled to a non-informative prior and a binomial likelihood function to create a posterior distribution for deployments of various subsystems uSing Monte Carlo Markov Chain sampling. Select distributions were then coupled to a subsequent analysis, using test data and anomaly occurrences on successive ground test deployments of scale model test articles of JWST hardware, to update the NASA heritage data. This allowed for a realistic prediction for the reliability of the complex Sunshield deployment, with credibility limits, within this two stage Bayesian framework
Regional vulnerability: the case of East Asia
In a case study of six East Asian economies, we use dynamic factor analysis to estimate a regional component of the exchange market pressure index (EMPI) as a measure of regional financial stress. The extent to which this indicator is explained by regional economic and financial factors is interpreted as regional vulnerability to crisis. We find that regional external liabilities and exuberance in domestic stock and credit markets, as well as the US high yield spread, were positively correlated with regional vulnerability. Individual country EMPIs are also explained by regional factors, with country-specific factors and trade linkages playing little role
Participatory politics, environmental journalism and newspaper campaigns
This is an Author's Accepted Manuscript of an article published in Journalism Studies, 13(2), 210 - 225, 2012, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/1461670X.2011.646398.This article explores the extent to which approaches to participatory politics might offer a more useful alternative to understanding the role of environmental journalism in a society where the old certainties have collapsed, only to be replaced by acute uncertainty. This uncertainty not only generates acute public anxiety about risks, it has also undermined confidence in the validity of long-standing premises about the ideal role of the media in society and journalistic professionalism. The consequence, this article argues, is that aspirations of objective reportage are outdated and ill-equipped to deal with many of the new risk stories environmental journalism covers. It is not a redrawing of boundaries that is needed but a wholesale relocation of our frameworks into approaches better suited to the socio-political conditions and uncertainties of late modernity. The exploration of participatory approaches is an attempt to suggest one way this might be done
Rise and fall of silicate dust in RS Ophiuchi following the 2006 eruption
Abstract We present an analysis of archival Spitzer InfraRed Spectrograph (IRS) observations of the recurrent nova RS Ophiuchi obtained on several occasions, beginning about 7 months after the outburst in 2006. These data show atomic emission lines, absorption bands due to photospheric SiO, and the well known silicate dust features at m and m. The dust emission, arising in the wind of the secondary star, is fitted by Dusty models for mass-loss rates in the range 1.0β1.7 Γ 10β7 Mβ yrβ1. The silicate features are similar in profile to those seen in circumstellar environments of isolated late-type stars and some dusty symbiotic binaries, although the longer wavelength feature peaks at m, instead of the usual m, indicating peculiar grain properties. The dust features are variable, appearing stronger in 2006-2007 during outburst than in 2008-2009 when the system was in the quiescent state. This variability is attributed to changes in the ultraviolet output and the reformation of the accretion disk, although a decline in the mass-loss rate of the red giant secondary star could also play a role. Further observations, in the aftermath of the 2021 eruption, could provide a definitive conclusion
Epigenome-wide association study of alcohol consumption in Nβ=β8161 individuals and relevance to alcohol use disorder pathophysiology:identification of the cystine/glutamate transporter SLC7A11 as a top target
Alcohol misuse is common in many societies worldwide and is associated with extensive morbidity and mortality, often leading to alcohol use disorders (AUD) and alcohol-related end-organ damage. The underlying mechanisms contributing to the development of AUD are largely unknown; however, growing evidence suggests that alcohol consumption is strongly associated with alterations in DNA methylation. Identification of alcohol-associated methylomic variation might provide novel insights into pathophysiology and novel treatment targets for AUD. Here we performed the largest single-cohort epigenome-wide association study (EWAS) of alcohol consumption to date (Nβ=β8161) and cross-validated findings in AUD populations with relevant endophenotypes, as well as alcohol-related animal models. Results showed 2504 CpGs significantly associated with alcohol consumption (Bonferroni p value < 6.8βΓβ10(β8)) with the five leading probes located in SLC7A11 (pβ=β7.75βΓβ10(β108)), JDP2 (pβ=β1.44βΓβ10(β56)), GAS5 (pβ=β2.71βΓβ10(β47)), TRA2B (pβ=β3.54βΓβ10(β42)), and SLC43A1 (pβ=β1.18βΓβ10(β40)). Genes annotated to associated CpG sites are implicated in liver and brain function, the cellular response to alcohol and alcohol-associated diseases, including hypertension and Alzheimerβs disease. Two-sample Mendelian randomization confirmed the causal relationship of consumption on AUD risk (inverse variance weighted (IVW) pβ=β5.37βΓβ10(β09)). A methylation-based predictor of alcohol consumption was able to discriminate AUD cases in two independent cohorts (pβ=β6.32βΓβ10(β38) and pβ=β5.41βΓβ10(β14)). The top EWAS probe cg06690548, located in the cystine/glutamate transporter SLC7A11, was replicated in an independent cohort of AUD and control participants (Nβ=β615) and showed strong hypomethylation in AUD (pβ<β10(β17)). Decreased CpG methylation at this probe was consistently associated with clinical measures including increased heavy drinking days (pβ<β10(β4)), increased liver function enzymes (GGT (pβ=β1.03βΓβ10(β21)), ALT (pβ=β1.29βΓβ10(β6)), and AST (pβ=β1.97βΓβ10(β8))) in individuals with AUD. Postmortem brain analyses documented increased SLC7A11 expression in the frontal cortex of individuals with AUD and animal models showed marked increased expression in liver, suggesting a mechanism by which alcohol leads to hypomethylation-induced overexpression of SLC7A11. Taken together, our EWAS discovery sample and subsequent validation of the top probe in AUD suggest a strong role of abnormal glutamate signaling mediated by methylomic variation in SLC7A11. Our data are intriguing given the prominent role of glutamate signaling in brain and liver and might provide an important target for therapeutic intervention
Infrared Absorption Investigations Confirm the Extraterrestrial Origin of Carbonado-Diamonds
The first complete infrared FTIR absorption spectra for carbonado-diamond
confirm the interstellar origin for the most enigmatic diamonds known as
carbonado. All previous attempts failed to measure the absorption of
carbonado-diamond in the most important IR-range of 1000-1300 cm-1 (10.00-7.69
micro-m.) because of silica inclusions. In our investigation, KBr pellets were
made from crushed silica-free carbonado-diamond and thin sections were also
prepared. The 100 to 1000 times brighter synchrotron infrared radiation permits
a greater spatial resolution. Inclusions and pore spaces were avoided and/or
sources of chemical contamination were removed. The FTIR spectra of
carbonado-diamond mostly depict the presence of single nitrogen impurities, and
hydrogen. The lack of identifiable nitrogen aggregates in the infrared spectra,
the presence of features related to hydrocarbon stretch bonds, and the
resemblance of the spectra to CVD and presolar diamonds indicate that
carbonado-diamonds formed in a hydrogen-rich interstellar environment. This is
consistent with carbonado-diamond being sintered and porous, with extremely
reduced metals, metal alloys, carbides and nitrides, light carbon isotopes,
surfaces with glassy melt-like patinas, deformation lamellae, and a complete
absence of primary, terrestrial mineral inclusions. The 2.6-3.8 billion year
old fragmented body was of asteroidal proportions
Healthy lifestyle interventions to combat noncommunicable disease : a novel nonhierarchical connectivity model for key stakeholders : a policy statement from the American Heart Association, European Society of Cardiology, European Association for Cardiovascular Prevention and Rehabilitation, and American College of Preventive Medicine
Β© 2015 Mayo Foundation for Medical Education and Research, and the European Society of Cardiology. This article is being published concurrently in Mayo Clinic Proceedings [1]. The articles are identical except for minor stylistic and spelling differences in keeping with each journal's style. Either citation can be used when citing this article. [1] Arena R, Guazzi M, Lianov L, Whitsel L, Berra K, Lavie CJ, Kaminsky L, Williams M, Hivert M-F, Franklin NC, Myers J, Dengel D, Lloyd-Jones DM, Pinto FJ, Cosentino F, Halle M, Gielen S, Dendale P, Niebauer J, Pelliccia A, Giannuzzi P, Corra U, Piepoli MF, Guthrie G, Shurney D. Healthy Lifestyle Interventions to Combat Noncommunicable Diseased - A Novel Nonhierarchical Connectivity Model for Key Stakeholders: A Policy Statement From the American Heart Association, European Society of Cardiology, European Association for Cardiovascular Prevention and Rehabilitation, and American College of Preventive Medicine. Mayo Clinic Proceedings 2015; DOI: 10.1016/j.mayocp.2015.05.001 [In Press]Noncommunicable diseases (NCDs) have become the primary health concern for most countries around the world. Currently, more than 36 million people worldwide die from NCDs each year, accounting for 63% of annual global deaths; most are preventable. The global financial burden of NCDs is staggering, with an estimated 2010 global cost of 13 trillion by 2030. A number of NCDs share one or more common predisposing risk factors, all related to lifestyle to some degree: (1) cigarette smoking, (2) hypertension, (3) hyperglycemia, (4) dyslipidemia, (5) obesity, (6) physical inactivity, and (7) poor nutrition. In large part, prevention, control, or even reversal of the aforementioned modifiable risk factors are realized through leading a healthy lifestyle (HL). The challenge is how to initiate the global change, not toward increasing documentation of the scope of the problem but toward true action-creating, implementing, and sustaining HL initiatives that will result in positive, measurable changes in the previously defined poor health metrics. To achieve this task, a paradigm shift in how we approach NCD prevention and treatment is required. The goal of this American Heart Association/European Society of Cardiology/European Association for Cardiovascular Prevention and Rehabilitation/American College of Preventive Medicine policy statement is to define key stakeholders and highlight their connectivity with respect to HL initiatives. This policy encourages integrated action by all stakeholders to create the needed paradigm shift and achieve broad adoption of HL behaviors on a global scale.info:eu-repo/semantics/publishedVersio
A Sustained Dietary Change Increases Epigenetic Variation in Isogenic Mice
Epigenetic changes can be induced by adverse environmental exposures, such as
nutritional imbalance, but little is known about the nature or extent of these
changes. Here we have explored the epigenomic effects of a sustained nutritional
change, excess dietary methyl donors, by assessing genomic CpG methylation
patterns in isogenic mice exposed for one or six generations. We find stochastic
variation in methylation levels at many loci; exposure to methyl donors
increases the magnitude of this variation and the number of variable loci.
Several gene ontology categories are significantly overrepresented in genes
proximal to these methylation-variable loci, suggesting that certain pathways
are susceptible to environmental influence on their epigenetic states. Long-term
exposure to the diet (six generations) results in a larger number of loci
exhibiting epigenetic variability, suggesting that some of the induced changes
are heritable. This finding presents the possibility that epigenetic variation
within populations can be induced by environmental change, providing a vehicle
for disease predisposition and possibly a substrate for natural selection
Elevated plasma levels of cardiac troponin-I predict left ventricular systolic dysfunction in patients with myotonic dystrophy type 1:A multicentre cohort follow-up study
Objective:
High sensitivity plasma cardiac troponin-I (cTnI) is emerging as a strong predictor of cardiac events in a variety of settings. We have explored its utility in patients with myotonic dystrophy type 1 (DM1).
Methods:
117 patients with DM1 were recruited from routine outpatient clinics across three health boards. A single measurement of cTnI was made using the ARCHITECT STAT Troponin I assay. Demographic, ECG, echocardiographic and other clinical data were obtained from electronic medical records. Follow up was for a mean of 23 months.
Results:
Fifty five females and 62 males (mean age 47.7 years) were included. Complete data were available for ECG in 107, echocardiography in 53. Muscle Impairment Rating Scale score was recorded for all patients. A highly significant excess (p = 0.0007) of DM1 patients presented with cTnI levels greater than the 99th centile of the range usually observed in the general population (9 patients; 7.6%). Three patients with elevated troponin were found to have left ventricular systolic dysfunction (LVSD), compared with four of those with normal range cTnI (33.3% versus 3.7%; p = 0.001). Sixty two patients had a cTnI level < 5ng/L, of whom only one had documented evidence of LVSD. Elevated cTnI was not predictive of severe conduction abnormalities on ECG, or presence of a cardiac device, nor did cTnI level correlate with muscle strength expressed by Muscle Impairment Rating Scale score.
Conclusions:
Plasma cTnI is highly elevated in some ambulatory patients with DM1 and shows promise as a tool to aid cardiac risk stratification, possibly by detecting myocardial involvement. Further studies with larger patient numbers are warranted to assess its utility in this setting
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