91 research outputs found

    LauncherOne Now in Orbit: Dedicated Air-Launch Brings Proven, Responsive Space Access with Historic NASA VCLS Demonstration Mission

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    The Launcher One air-launched rocket system, under commercial development by Virgin Orbit since 2015, is now fully flight-qualified. This small, dedicated launch vehicle first reached orbit on January 17th, 2021 as part of the NASA Venture Class Launch Services (VCLS) ELaNa 20 mission, injecting ten small satellites into orbit. This historic mission saw the world’s first liquid-propulsion, orbital class air-launched vehicle succeed with incredible performance and accuracy. Founded upon the capabilities of the Boeing 747-400 carrier aircraft, LauncherOne maintains safe operations using flight controls and an Autonomous Flight Safety System (AFSS) that have been fully internally-developed and certified by the Federal Aviation Administration (FAA) of the United States. T his uniquely mobile launch system is designed to bring tailored small satellite launch services to any corner of the globe. This paper details the inaugural NASA VCLS LauncherOne mission. Review of the mission and customer outcome will reveal how some of the most challenging aspects of air-launch have now been achieved by the LauncherOne design. In successfully overcoming the design challenges of a cryogenic air-launch vehicle, the substantial accompanying rewards can now be realized. We have shown how such a modular launch system can be replicated and disaggregated across many sites, offering flexibility and extreme orbital access for small satellites without a fixed infrastructure or permanent footprint. Accordingly, we have continued to grow our spaceport network to support domestic and international mission planners that benefit from such a capability. The status of these activities and facilities will be discussed. Following extensive qualification testing, the NASA VCLS mission success, and all of the associated cryogenic loading and vehicle preparation operations successfully completed from an austere runway apron, LauncherOne’s air-launch approach is now proven to be foundationally responsive. Virgin Orbit and the dedicated, flight-proven LauncherOne system are now uniquely positioned to both serve and grow the global small satellite market from spaceports around the world

    Burden of disease resulting from lead exposure at toxic waste sites in Argentina, Mexico and Uruguay

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    Background: Though lead contaminated waste sites have been widely researched in many high-income countries, their prevalence and associated health outcomes have not been well documented in low- and middle-income countries. Methods: Using the well-established health metric disability-adjusted life year (DALY) and an exposure assessment method developed by Chatham-Stephens et al., we estimated the burden of disease resulting from exposure to lead at toxic waste sites in three Latin American countries in 2012: Argentina, Mexico and Uruguay. Toxic waste sites identified through Pure Earth’s Toxic Sites Identification Program (TSIP) were screened for lead in both biological and environmental sample media. Estimates of cardiovascular disease incidence and other outcomes resulting from exposure to lead were utilized to estimate DALYs for each population at risk. Results: Approximately 316,703 persons in three countries were at risk of exposure to pollutants at 129 unique sites identified through the TSIP database. Exposure to lead was estimated to result in between 51,432 and 115,042 DALYs, depending on the weighting factor used. The estimated burden of disease caused by exposure to lead in this analysis is comparable to that estimated for Parkinson’s disease and bladder cancer in these countries. Conclusions: Lead continues to pose a significant public health risk in Argentina, Mexico, and Uruguay. The burden of disease in these three countries is comparable with other widely recognized public health challenges. Knowledge of the relatively high number of DALYs associated with lead exposure may be used to generate support and funding for the remediation of toxic waste sites in these countries and others

    Prevalence of liver disease in veterans with bipolar disorder or schizophrenia

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    Objective: To assess the prevalence of three liver diseases [hepatitis C virus (HCV), nonalcoholic fatty liver disease and alcohol-induced cirrhosis] in patients (veterans) with/without schizophrenia/schizoaffective disorder and bipolar disorder. Methods: A retrospective electronic chart review of Veterans Integrated Services Network 20 facilities from January 1, 2001 to December 21, 2006 selected patients to one of two groups: schizophrenia/schizoaffective disorder or bipolar disorder. Patients in both groups were compared with veterans in an equal-sized random sample from the same data set of veterans without psychiatric diagnoses. Logistic regression models evaluated risk for overall liver diseases as well as HCV, nonalcoholic fatty liver disease and alcoholic-induced cirrhosis. Results: Patients with schizophrenia (n=6521) had a higher prevalence of liver disease [22.4% versus 3.2%; odds ratio (OR)=8.73]; HCV (16.5% versus 1.9%; OR=10.21); and alcohol-related cirrhosis (1.6% versus 0.4%; OR=4.09) than matched controls. Patients with bipolar disorder (n=5319) had a higher prevalence of liver disease (21.5% versus 3.5%; OR=7.58); HCV (15.5% versus 2.1%; OR=8.60); and alcohol-related cirrhosis (1.6% versus 0.4%; OR=3.82) than matched controls. Risk factors for liver disease in patients with schizophrenia (versus matched controls) included diabetes (OR=1.29), hypertension (OR=1.27), HIV (OR=3.54), substance use disorder (SUD) (OR=2.28), alcohol use disorder (OR=3.05) and schizophrenia (OR=2.74). Risk factors for development of liver disease for patients with bipolar disorder: diabetes (OR=1.40), HIV (OR=3.66), SUD (OR=2.68), alcohol use disorder (OR=3.22) and bipolar disorder (OR=2.27). Conclusions: This study in veterans shows that the presence of mental illness and its comorbidities represents a significant risk factor for the diagnosis of liver disease, including HCV and alcohol-related cirrhosis

    Global Burden of Disease of Mercury Used in Artisanal Small-Scale Gold Mining

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    BACKGROUND Artisanal small-scale gold mining (ASGM) is the world's largest anthropogenic source of mercury emission. Gold miners are highly exposed to metallic mercury and suffer occupational mercury intoxication. The global disease burden as a result of this exposure is largely unknown because the informal character of ASGM restricts the availability of reliable data. OBJECTIVE To estimate the prevalence of occupational mercury intoxication and the disability-adjusted life years (DALYs) attributable to chronic metallic mercury vapor intoxication (CMMVI) among ASGM gold miners globally and in selected countries. METHODS Estimates of the number of artisanal small-scale gold (ASG) miners were extracted from reviews supplemented by a literature search. Prevalence of moderate CMMVI among miners was determined by compiling a dataset of available studies that assessed frequency of intoxication in gold miners using a standardized diagnostic tool and biomonitoring data on mercury in urine. Severe cases of CMMVI were not included because it was assumed that these persons can no longer be employed as miners. Cases in workers' families and communities were not considered. Years lived with disability as a result of CMMVI among ASG miners were quantified by multiplying the number of prevalent cases of CMMVI by the appropriate disability weight. No deaths are expected to result from CMMVI and therefore years of life lost were not calculated. Disease burden was calculated by multiplying the prevalence rate with the number of miners for each country and the disability weight. Sensitivity analyses were performed using different assumptions on the number of miners and the intoxication prevalence rate. FINDINGS Globally, 14-19 million workers are employed as ASG miners. Based on human biomonitoring data, between 25% and 33% of these miners-3.3-6.5 million miners globally-suffer from moderate CMMVI. The resulting global burden of disease is estimated to range from 1.22 (uncertainty interval [UI] 0.87-1.61) to 2.39 (UI 1.69-3.14) million DALYs. CONCLUSIONS This study presents the first global and country-based estimates of disease burden caused by mercury intoxication in ASGM. Data availability and quality limit the results, and the total disease burden is likely undercounted. Despite these limitations, the data clearly indicate that mercury intoxication in ASG miners is a major, largely neglected global health problem

    Burden of Disease from Toxic Waste Sites in India, Indonesia, and the Philippines in 2010

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    Background: Prior calculations of the burden of disease from toxic exposures have not included estimates of the burden from toxic waste sites due to the absence of exposure data. Objective: We developed a disability-adjusted life year (DALY)-based estimate of the disease burden attributable to toxic waste sites. We focused on three low- and middle-income countries (LMICs): India, Indonesia, and the Philippines. Methods: Sites were identified through the Blacksmith Institute’s Toxic Sites Identification Program, a global effort to identify waste sites in LMICs. At least one of eight toxic chemicals was sampled in environmental media at each site, and the population at risk estimated. By combining estimates of disease incidence from these exposures with population data, we calculated the DALYs attributable to exposures at each site. Results: We estimated that in 2010, 8,629,750 persons were at risk of exposure to industrial pollutants at 373 toxic waste sites in the three countries, and that these exposures resulted in 828,722 DALYs, with a range of 814,934–1,557,121 DALYs, depending on the weighting factor used. This disease burden is comparable to estimated burdens for outdoor air pollution (1,448,612 DALYs) and malaria (725,000 DALYs) in these countries. Lead and hexavalent chromium collectively accounted for 99.2% of the total DALYs for the chemicals evaluated. Conclusions: Toxic waste sites are responsible for a significant burden of disease in LMICs. Although some factors, such as unidentified and unscreened sites, may cause our estimate to be an underestimate of the actual burden of disease, other factors, such as extrapolation of environmental sampling to the entire exposed population, may result in an overestimate of the burden of disease attributable to these sites. Toxic waste sites are a major, and heretofore underrecognized, global health problem

    Conformations of Linear DNA

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    We examine the conformations of a model for under- and overwound DNA. The molecule is represented as a cylindrically symmetric elastic string subjected to a stretching force and to constraints corresponding to a specification of the link number. We derive a fundamental relation between the Euler angles that describe the curve and the topological linking number. Analytical expressions for the spatial configurations of the molecule in the infinite- length limit were obtained. A unique configuraion minimizes the energy for a given set of physical conditions. An elastic model incorporating thermal fluctuations provides excellent agreement with experimental results on the plectonemic transition.Comment: 5 pages, RevTeX; 6 postscript figure
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