25 research outputs found
Test results of the DOE/Sandia 17 meter VAWT
A review is given of the test program of a 17 meter Vertical Axis Wind Turbine VAWT. Performance test results are discussed including difficulties encountered during the VAWT operation along with ways of solving these problems
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Active resonant subwavelength grating for scannerless range imaging sensors.
In this late-start LDRD, we will present a design for a wavelength-agile, high-speed modulator that enables a long-term vision for the THz Scannerless Range Imaging (SRI) sensor. It takes the place of the currently-utilized SRI micro-channel plate which is limited to photocathode sensitive wavelengths (primarily in the visible and near-IR regimes). Two of Sandia's successful technologies--subwavelength diffractive optics and THz sources and detectors--are poised to extend the capabilities of the SRI sensor. The goal is to drastically broaden the SRI's sensing waveband--all the way to the THz regime--so the sensor can see through image-obscuring, scattering environments like smoke and dust. Surface properties, such as reflectivity, emissivity, and scattering roughness, vary greatly with the illuminating wavelength. Thus, objects that are difficult to image at the SRI sensor's present near-IR wavelengths may be imaged more easily at the considerably longer THz wavelengths (0.1 to 1mm). The proposed component is an active Resonant Subwavelength Grating (RSG). Sandia invested considerable effort on a passive RSG two years ago, which resulted in a highly-efficient (reflectivity greater than gold), wavelength-specific reflector. For this late-start LDRD proposal, we will transform the passive RSG design into an active laser-line reflector
Global patterns of mortality in international migrants: a systematic review and meta-analysis.
BACKGROUND: 258 million people reside outside their country of birth; however, to date no global systematic reviews or meta-analyses of mortality data for these international migrants have been done. We aimed to review and synthesise available mortality data on international migrants. METHODS: In this systematic review and meta-analysis, we searched MEDLINE, Embase, the Cochrane Library, and Google Scholar databases for observational studies, systematic reviews, and randomised controlled trials published between Jan 1, 2001, and March 31, 2017, without language restrictions. We included studies reporting mortality outcomes for international migrants of any age residing outside their country of birth. Studies that recruited participants exclusively from intensive care or high dependency hospital units, with an existing health condition or status, or a particular health exposure were excluded. We also excluded studies limited to maternal or perinatal outcomes. We screened studies using systematic review software and extracted data from published reports. The main outcomes were all-cause and International Classification of Diseases, tenth revision (ICD-10) cause-specific standardised mortality ratios (SMRs) and absolute mortality rates. We calculated summary estimates using random-effects models. This study is registered with PROSPERO, number CRD42017073608. FINDINGS: Of the 12 480 articles identified by our search, 96 studies were eligible for inclusion. The studies were geographically diverse and included data from all global regions and for 92 countries. 5464 mortality estimates for more than 15·2 million migrants were included, of which 5327 (97%) were from high-income countries, 115 (2%) were from middle-income countries, and 22 (<1%) were from low-income countries. Few studies included mortality estimates for refugees (110 estimates), asylum seekers (144 estimates), or labour migrants (six estimates). The summary estimate of all-cause SMR for international migrants was lower than one when compared with the general population in destination countries (0·70 [95% CI 0·65-0·76]; I2=99·8%). All-cause SMR was lower in both male migrants (0·72 [0·63-0·81]; I2=99·8%) and female migrants (0·75 [0·67-0·84]; I2=99·8%) compared with the general population. A mortality advantage was evident for refugees (SMR 0·50 [0·46-0·54]; I2=89·8%), but not for asylum seekers (1·05 [0·89-1·24]; I2=54·4%), although limited data was available on these groups. SMRs for all causes of death were lower in migrants compared with the general populations in the destination country across all 13 ICD-10 categories analysed, with the exception of infectious diseases and external causes. Heterogeneity was high across the majority of analyses. Point estimates of all-cause age-standardised mortality in migrants ranged from 420 to 874 per 100 000 population. INTERPRETATION: Our study showed that international migrants have a mortality advantage compared with general populations, and that this advantage persisted across the majority of ICD-10 disease categories. The mortality advantage identified will be representative of international migrants in high-income countries who are studying, working, or have joined family members in these countries. However, our results might not reflect the health outcomes of more marginalised groups in low-income and middle-income countries because little data were available for these groups, highlighting an important gap in existing research. Our results present an opportunity to reframe the public discourse on international migration and health in high-income countries. FUNDING: Wellcome Trust, National Institute for Health Research, Medical Research Council, Alliance for Health Policy and Systems Research, Department for International Development, Fogarty International Center, Grand Challenges Canada, International Development Research Centre Canada, Inter-American Institute for Global Change Research, National Cancer Institute, National Heart, Lung and Blood Institute, National Institute of Mental Health, Swiss National Science Foundation, World Diabetes Foundation, UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, and European Society for Clinical Microbiology and Infectious Diseases (ESCMID) Study Group Research Funding for the ESCMID Study Group for Infections in Travellers and Migrants
Ethnicity and COVID-19 outcomes among healthcare workers in the UK:UK-REACH ethico-legal research, qualitative research on healthcare workers’ experiences and stakeholder engagement protocol
ntroduction As the world continues to grapple with the COVID-19 pandemic, emerging evidence suggests that individuals from ethnic minority backgrounds may be disproportionately affected. The United Kingdom Research study into Ethnicity And COVID-19 outcomes in Healthcare workers (UK-REACH) project has been initiated to generate rapid evidence on whether and why ethnicity affects COVID-19 diagnosis and clinical outcomes in healthcare workers (HCWs) in the UK, through five interlinked work packages/work streams, three of which form the basis of this protocol. The ethico-legal work (Work Package 3) aims to understand and address legal, ethical and acceptability issues around big data research; the HCWs' experiences study (Work Package 4) explores their work and personal experiences, perceptions of risk, support and coping mechanisms; the stakeholder engagement work (Work Package 5) aims to provide feedback and support with the formulation and dissemination of the project recommendations.Methods and analysis Work Package 3 has two different research strands: (A) desk-based doctrinal research; and (B) empirical qualitative research with key opinion leaders. For the empirical research, in-depth interviews will be conducted digitally and recorded with participants’ permission. Recordings will be transcribed, coded and analysed using thematic analysis. In Work Package 4, online in-depth interviews and focus groups will be conducted with approximately 150 HCWs, from across the UK, and these will be recorded with participants’ consent. The recordings will be transcribed and coded and data will be analysed using thematic analysis. Work Package 5 will achieve its objectives through regular group meetings and in-group discussions.Ethics and dissemination Ethical approval has been received from the London-Brighton & Sussex Research Ethics Committee of the Health Research Authority (Ref No 20/HRA/4718). Results of the study will be published in open-access journals, and disseminated through conference presentations, project website, stakeholder organisations, media and scientific advisory groups.Trial registration number ISRCTN11811602
Ethnic differences in SARS-CoV-2 vaccine hesitancy in United Kingdom healthcare workers: Results from the UK-REACH prospective nationwide cohort study
Background: In most countries, healthcare workers (HCWs) represent a priority group for vaccination against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) due to their elevated risk of COVID-19 and potential contribution to nosocomial SARS-CoV-2 transmission. Concerns have been raised that HCWs from ethnic minority groups are more likely to be vaccine hesitant (defined by the World Health Organisation as refusing or delaying a vaccination) than those of White ethnicity, but there are limited data on SARS-CoV-2 vaccine hesitancy and its predictors in UK HCWs. Methods: Nationwide prospective cohort study and qualitative study in a multi-ethnic cohort of clinical and non-clinical UK HCWs. We analysed ethnic differences in SARS-CoV-2 vaccine hesitancy adjusting for demographics, vaccine trust, and perceived risk of COVID-19. We explored reasons for hesitancy in qualitative data using a framework analysis. Findings: 11,584 HCWs were included in the cohort analysis. 23% (2704) reported vaccine hesitancy. Compared to White British HCWs (21.3% hesitant), HCWs from Black Caribbean (54.2%), Mixed White and Black Caribbean (38.1%), Black African (34.4%), Chinese (33.1%), Pakistani (30.4%), and White Other (28.7%) ethnic groups were significantly more likely to be hesitant. In adjusted analysis, Black Caribbean (aOR 3.37, 95% CI 2.11 - 5.37), Black African (aOR 2.05, 95% CI 1.49 - 2.82), White Other ethnic groups (aOR 1.48, 95% CI 1.19 - 1.84) were significantly more likely to be hesitant. Other independent predictors of hesitancy were younger age, female sex, higher score on a COVID-19 conspiracy beliefs scale, lower trust in employer, lack of influenza vaccine uptake in the previous season, previous COVID-19, and pregnancy. Qualitative data from 99 participants identified the following contributors to hesitancy: lack of trust in government and employers, safety concerns due to the speed of vaccine development, lack of ethnic diversity in vaccine studies, and confusing and conflicting information. Participants felt uptake in ethnic minority communities might be improved through inclusive communication, involving HCWs in the vaccine rollout, and promoting vaccination through trusted networks. Interpretation: Despite increased risk of COVID-19, HCWs from some ethnic minority groups are more likely to be vaccine hesitant than their White British colleagues. Strategies to build trust and dispel myths surrounding the COVID-19 vaccine in these communities are urgently required. Emphasis should be placed on the safety and benefit of SARS-CoV-2 vaccination in pregnancy and in those with previous COVID-19. Public health communications should be inclusive, non-stigmatising and utilise trusted networks
Multidrug-resistant tuberculosis treatment adherence in migrants: a systematic review and meta-analysis.
BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) is a growing concern in meeting global targets for TB control. In high-income low-TB-incidence countries, a disproportionate number of MDR-TB cases occur in migrant (foreign-born) populations, with concerns about low adherence rates in these patients compared to the host non-migrant population. Tackling MDR-TB in this context may, therefore, require unique approaches. We conducted a systematic review and meta-analysis to identify and synthesise data on MDR-TB treatment adherence in migrant patients to inform evidence-based strategies to improve care pathways and health outcomes in this group. METHODS: This systematic review and meta-analysis was conducted in line with PRISMA guidelines (PROSPERO 42017070756). The databases Embase, MEDLINE, Global Health and PubMed were searched to 24 May 2017 for primary research reporting MDR-TB treatment adherence and outcomes in migrant populations, with no restrictions on dates or language. A meta-analysis was conducted using random-effects models. RESULTS: From 413 papers identified in the database search, 15 studies reporting on MDR-TB treatment outcomes for 258 migrants and 174 non-migrants were included in the systematic review and meta-analysis. The estimated rate of adherence to MDR-TB treatment across migrant patients was 71% [95% confidence interval (CI) = 58-84%], with non-adherence reported among 20% (95% CI = 4-37%) of migrant patients. A key finding was that there were no differences in estimated rates of adherence [risk ratio (RR) = 1.05; 95% CI = 0.82-1.34] or non-adherence (RR = 0.97; 95% CI = 0.79-1.36) between migrants and non-migrants. CONCLUSIONS: MDR-TB treatment adherence rates among migrants in high-income low-TB-incidence countries are approaching global targets for treatment success (75%), and are comparable to rates in non-migrants. The findings highlight that only just over 70% of migrant and non-migrant patients adhere to MDR-TB treatment. The results point to the importance of increasing adherence in all patient groups, including migrants, with an emphasis on tailoring care based on social risk factors for poor adherence. We believe that MDR-TB treatment targets are not ambitious enough
Migrant and refugee populations: a public health and policy perspective on a continuing global crisis.
The 2015-2017 global migratory crisis saw unprecedented numbers of people on the move and tremendous diversity in terms of age, gender and medical requirements. This article focuses on key emerging public health issues around migrant populations and their interactions with host populations. Basic needs and rights of migrants and refugees are not always respected in regard to article 25 of the Universal Declaration of Human Rights and article 23 of the Refugee Convention. These are populations with varying degrees of vulnerability and needs in terms of protection, security, rights, and access to healthcare. Their health status, initially conditioned by the situation at the point of origin, is often jeopardised by adverse conditions along migratory paths and in intermediate and final destination countries. Due to their condition, forcibly displaced migrants and refugees face a triple burden of non-communicable diseases, infectious diseases, and mental health issues. There are specific challenges regarding chronic infectious and neglected tropical diseases, for which awareness in host countries is imperative. Health risks in terms of susceptibility to, and dissemination of, infectious diseases are not unidirectional. The response, including the humanitarian effort, whose aim is to guarantee access to basic needs (food, water and sanitation, healthcare), is gripped with numerous challenges. Evaluation of current policy shows insufficiency regarding the provision of basic needs to migrant populations, even in the countries that do the most. Governments around the world need to rise to the occasion and adopt policies that guarantee universal health coverage, for migrants and refugees, as well as host populations, in accordance with the UN Sustainable Development Goals. An expert consultation was carried out in the form of a pre-conference workshop during the 4th International Conference on Prevention and Infection Control (ICPIC) in Geneva, Switzerland, on 20 June 2017, the United Nations World Refugee Day
Preparation and characterization of nanothermite inks for direct deposition on initiation devices
Nanothermites show promise as a replacement for energetic materials in many devices but their use has been limited by high sensitivity during processing, hazardous processing solvents, and time consuming deposition. Incorporating processing and deposition into a single step, especially if no organic solvents were used, could allow nanothermites to be applied in a wider range of applications. First, this work reports on the performance and mixing quality of nanothermites prepared in a LabRAM resonant mixer at high solids loadings as compared to traditional ultrasonic mixing. Specifically, the aluminum-bismuth (III) oxide (Al/Bi2O3) system processed in N,N-dimethylformamide (DMF) was investigated. It was found that the performance and quality of mixing were correlated to the volumetric solids loading during processing; increasing volumetric solids loading decreases separation of particles, leading to more intimate mixing. The measured performance of this system processed in DMF at 30 vol.% was similar to traditionally sonicated mixtures in hexanes, uses significantly less solvent, results in a higher density final material, and can be scaled. Second, this work investigates the replacement of the processing solvent DMF with water. Processing safety was characterized by measurement of thermal rise during mixing, stability at elevated temperature, and electrostatic discharge (ESD) sensitivity. Mixture performance was characterized via semi-conductor bridge (SCB) ignition threshold, Parr cell ignition delay and Parr cell pressurization rate. It was found that nanothermites processed in water performed similarly to nanothermites processed in DMF, although secondary interactions between aluminum and water caused heating that could be dangerous in scaled nanothermite batches. This secondary interaction was eliminated by coating both metal and metal oxide with an organic acid. In addition, processing in water at a solids loading of 30 vol.% resulted in a high performance ink that was deposited into SCB initiators, resulting in a 25% reduction in the all fire threshold over traditional energetics. This work incorporates both water processing and resonant mixing with the preparation of nanoenergetics. This method uses an environmentally friendly mixing medium, can result in a higher density final material, and allows one-step mixing and deposition without a significant decrease in performance when compared to traditionally prepared nanothermites