159 research outputs found
Radioactive decay simulations for testing of the timing detectors in the Nab experiment
Located at the Spallation Neutron Source in Oak Ridge National Lab, the Nab experiment aims to yield a measurement of the electron-neutrino correlation parameter, a, and the Fierz interference term, b, in neutron beta decay. These parameters are located in the energy and the angular distribution of the particles produced through neutron beta decay. Using silicon detectors, a direct measurement of the phase space distribution of the resultant electron energy and proton momentum can be obtained. The silicon detectors of the Nab experiment will be tested using well-known radioactive isotopes. Simulations of systematic testing use the associated energy levels, decay probabilities, and decay options of radioactive sources such as Ce-139, Ba-133, and Sn-113 to determine the expected results of experimental testing. Presented here is an analysis of the Monte Carlo simulations of the radioactive decay of Ce-139, Ba-133, and Sn-113, and their ability to be useful to the Nab experiment as a whole
Observing UK Bonfire Night pollution from space: analysis of atmospheric aerosol
UK Bonfire Night (BFN) is an annual event on 5 November which celebrates the failed ‘gunpowder plot’ of Guy Fawkes, who intended to blow up the Houses of Parliament. This event is celebrated with firework and bonfire displays, which reduce visibility and increase air pollutant concentrations. A two- to four-fold increase in particulate matter concentrations was seen at some surface monitoring sites. Satellite measurements of aerosol optical depth found increases of 10–90% between days before and after BFN
The PM10 fraction of road dust in the UK and India:Characterization, source profiles and oxidative potential
Behavioral economics e defesa do consumidor: uma aproximação pertinente?
Objetiva-se demonstrar como a Behavioral Economics e o Direito do Consumidor se entrelaçam e podem se valer uma da outra para a explicação de fenômenos e a construção de soluções que atendam ao ditame constitucional da tutela consumerista. O método dedutivo foi aplicado pelo enfrentamento do princípio da vulnerabilidade do consumidor e de seu cotejo com a racionalidade limitada dos agentes, base teórica do comportamentalismo para demonstrar a viabilidade da aproximação juseconômica. Foi imprescindível demonstrar a impossibilidade de se negar a feição econômica do Direito do Consumidor e como tal constatação pode contribuir para melhor compreensão e efetivação da tutela consumerista. Concluiu-se a convergência entre a vulnerabilidade consumerista e a racionalidade limitada, o que permite a utilização da Behavioral Economics para explicar os fenômenos do superendividamento do consumidor e do Financiamento Coletivo/Crowdfunding, bem como para apresentar possíveis soluções e medidas de incentivo para os aludidos fenômenos
Triangulação em Estudos de Caso: incidência, apropriações e mal-entendidos em pesquisas da área de Administração
O artigo apresenta uma análise bibliométrica em que se identifica a incidência do uso e apropriações da triangulação como estratégia metodológica em Estudos de Caso publicados em periódicos científicos da área de Administração no Brasil. Entende-se a triangulação como uma estratégia importante para aumentar a compreensão em profundidade dos fenômenos estudados, bem como atribuir maior confiabilidade e fidedignidade aos Estudos de Caso e discutem-se cinco modalidades de triangulação: (i) triangulação de fontes de evidência, (ii) de métodos, (iii) de investigadores, (iv) teórica, e (v) a técnica de triangulação tal como proposta por Triviños (1987). A pesquisa analisou uma amostra de 1384 Estudos de Caso publicados entre os anos de 2008 e 2012 em periódicos da área classificados como A1 até B1 pela Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – CAPES (conforme evento de qualificação Qualis 2013). Os resultados permitem concluir que a triangulação é pouco utilizada em Estudo de Caso na área de Administração nacional (é relatada em apenas 12% dos estudos analisados). Nos poucos casos em que é utilizada, os tipos de triangulação privilegiadas são as de fontes de evidência (100%) e as de método (86,72%), sendo raros estudos de caso que relatam a realização de triangulação teórica, de investigadores, ou técnicas de triangulação sistematizadas, como a proposta por Triviños (1987). Além da incidência e da apropriação que se faz da triangulação, foram identificados diversos equívocos no relato da utilização de triangulação. O texto explora esses mal-entendidos e apresenta sugestões para garantir o correto uso e relato da triangulação. Justifica-se a relevância do artigo dada a necessidade de refletir sobre a qualidade dos procedimentos metodológicos e dos relatos de pesquisa que se tem realizado na área de Administração
Trace Metal Exposure is Associated with Increased Exhaled Nitric Oxide in Asthmatic Children
Background Children with asthma experience increased susceptibility to airborne pollutants. Exposure to traffic and industrial activity have been positively associated with exacerbation of symptoms as well as emergency room visits and hospitalisations. The effect of trace metals contained in fine particulate matter (aerodynamic diameter 2.5 μm and lower, PM2.5) on acute health effects amongst asthmatic children has not been well investigated. The objective of this panel study in asthmatic children was to determine the association between personal daily exposure to ambient trace metals and airway inflammation, as measured by fractional exhaled nitric oxide (FeNO). Methods Daily concentrations of trace metals contained on PM2.5 were determined from personal samples (n = 217) collected from 70 asthmatic school aged children in Montreal, Canada, over ten consecutive days. FeNO was measured daily using standard techniques. Results A positive association was found between FeNO and children’s exposure to an indicator of vehicular non-tailpipe emissions (8.9 % increase for an increase in the interquartile range (IQR) in barium, 95 % confidence interval (CI): 2.8, 15.4) as well as exposure to an indicator of industrial emissions (7.6 % increase per IQR increase in vanadium, 95 % CI: 0.1, 15.8). Elevated FeNO was also suggested for other metals on the day after the exposure: 10.3 % increase per IQR increase in aluminium (95 % CI: 4.2, 16.6) and 7.5 % increase per IQR increase in iron (95 % CI: 1.5, 13.9) at a 1-day lag period. Conclusions Exposures to ambient PM2.5 containing trace metals that are markers of traffic and industrial-derived emissions were associated in asthmatic children with an enhanced FeNO response
Dataset associated with "Unequal airborne exposure burden to toxic metals is associated with race, ethnicity, and segregation"
This dataset contains annual and county-level mean concentrations and mass proportions of fine particulate metals (aggregated from the EPA's CSN/IMPROVE networks), associated minimum detectable limit for each monitor, as well as racial and ethnic demographic population data. This dataset is aggregated from publicly available air pollutant data from the EPA (http://views.cira.colostate.edu/fed/QueryWizard/Default.aspx) and the US Census Bureau (https://data.census.gov/cedsci/). This dataset is used to examine the association of racial residential segregation with fine particulate metal concentrations. The time period ranges from year 2009 to 2019.- Columns labeled "XX_concentration" report the annual and county-level mean concentration in ug m-3
- Columns labeled 'XX_content" report the mass proportion of fine particulate metals relative to PM2.5 mass
- Columns labeled "XX_mdl" report the minimum detectable limit for that species at that monitor. In the case of more than one monitor in the county, this column reports the average.
- Columns labeled "DI_XX" report the dissimilarity index for the racial/ethnic group using the non-Hispanic White population as the reference population (see associated manuscript for details), where "NHB" corresponds to non-Hispanic Black and "native_amer" to "Native American".
- Columns labeled "XX_pop_county" report the county population of the respective racial/ethnic group. These groupings reflect the identification made by individuals in US Census Bureau data. "NHW" refers to "non-Hispanic White".
- "CountyFIPS" refers to the county FIPS code.
- "Latitude" and "Longitude" reflect the coordinates of the monitor in degrees. In the case of more than one monitor per county, these columns averages.Communities of color have been exposed to a disproportionate burden of air pollution across the United States for decades. Yet, the inequality in exposure to known toxic elements of air pollution is unclear. Here, we find that populations living in racially segregated communities are exposed to a form of fine particulate matter with over three times higher mass proportions of known toxic and carcinogenic metals. While concentrations of total fine particulate matter are two times higher in racially segregated communities, concentrations of metals from anthropogenic sources are nearly ten times higher. Populations living in racially segregated communities have been disproportionately exposed to these environmental stressors throughout the past decade. We find evidence, however, that these disproportionate exposures may be abated though targeted regulatory action. For example, recent regulations on marine fuel oil not only reduced vanadium concentrations in coastal cities, but also sharply lessened differences in vanadium exposure by segregation.This work was supported financially by grants from the Health Effects Institute under grant number 4953- RFA14-3/16-4 awarded to FD, National Institute of Health under grant numbers DP2MD012722 and P50MD010428 awarded to FD, National Institute of Health and National Institute of Environmental Health Sciences under grant number R01 ES028033 awarded to FD, National Institute of Health and Columbia University under grant number 1R01ES030616 awarded to FD, the National Institute On Minority Health And Health Disparities of the National Institutes of Health under award number R01MD012769 awarded to MLB and FD, the Environmental Protection Agency under grant number 83587201-0 awarded to FD and grant number RD83587101 awarded to MLB, The Climate Change Solutions Fund, and the Harvard Star Friedman Award. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Environmental Protection Agency
COVID-19 update: the first 6 months of the pandemic
The COVID-19 pandemic is sweeping the world and will feature prominently in all our lives for months and most likely for years to come. We review here the current state 6 months into the declared pandemic. Specifically, we examine the role of the pathogen, the host and the environment along with the possible role of diabetes. We also firmly believe that the pandemic has shown an extraordinary light on national and international politicians whom we should hold to account as performance has been uneven. We also call explicitly on competent leadership of international organizations, specifically the WHO, UN and EU, informed by science. Finally, we also condense successful strategies for dealing with the current COVID-19 pandemic in democratic countries into a developing pandemic playbook and chart a way forward into the future. This is useful in the current COVID-19 pandemic and, we hope, in a very distant future again when another pandemic might arise
Axiomas da Lei de Recuperação Judicial e Falências: entre a preservação da empresa e a tutela do crédito
A recente reforma do sistema falimentar brasileiro pela Lei n°. 14.112/2020 é indicativa da constante preocupação com os impactos da crise da empresa no mercado, na economia e na sociedade. A crise empresarial afeta não somente o devedor e seus sócios, mas seus colaboradores, consumidores, fornecedores e outros agentes de mercado, com importantes externalidades. Daí as dificuldades inerentes à busca de equilíbrio na tutela dos interesses do devedor empresário e dos credores, para que não haja distorção de incentivos. Nesse cenário, o presente artigo pretende analisar os objetivos de um sistema falimentar, pelo estudo dos axiomas tradicionalista e procedimentalista, para, a partir de então, analisar sua aplicabilidade à disciplina da Lei n°. 11.101/2005. Pelo método dedutivo, mediante pesquisa bibliográfica, conclui-se que o regime recuperacional brasileiro, tal como o regime de falência, guarda feições do axioma procedimentalista, em razão da preocupação do legislador com os impactos e efeitos ex ante das regras legais sobre o comportamento e na tomada de decisão pelos agentes econômicos.
Particulate oxidative burden as a predictor of exhaled nitric oxide in children with asthma
Background:
Epidemiological studies have provided strong evidence that fine particulate matter (PM2.5; aerodynamic diameter ≤ 2.5 μm) can exacerbate asthmatic symptoms in children. Pro-oxidant components of PM2.5 are capable of directly generating reactive oxygen species. Oxidative burden is used to describe the capacity of PM2.5 to generate reactive oxygen species in the lung.
Objective:
In this study we investigated the association between airway inflammation in asthmatic children and oxidative burden of PM2.5 personal exposure.
Methods:
Daily PM2.5 personal exposure samples (n = 249) of 62 asthmatic school-aged children in Montreal were collected over 10 consecutive days. The oxidative burden of PM2.5 samples was determined in vitro as the depletion of low-molecular-weight antioxidants (ascorbate and glutathione) from a synthetic model of the fluid lining the respiratory tract. Airway inflammation was measured daily as fractional exhaled nitric oxide (FeNO).
Results:
A positive association was identified between FeNO and glutathione-related oxidative burden exposure in the previous 24 hr (6.0% increase per interquartile range change in glutathione). Glutathione-related oxidative burden was further found to be positively associated with FeNO over 1-day lag and 2-day lag periods. Results further demonstrate that corticosteroid use may reduce the FeNO response to elevated glutathione-related oxidative burden exposure (no use, 15.8%; irregular use, 3.8%), whereas mold (22.1%), dust (10.6%), or fur (13.1%) allergies may increase FeNO in children with versus children without these allergies (11.5%). No association was found between PM2.5 mass or ascorbate-related oxidative burden and FeNO levels.
Conclusions:
Exposure to PM2.5 with elevated glutathione-related oxidative burden was associated with increased FeNO
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