6,977 research outputs found
Effect of gravity on methane-air combustion
Analytical and numerical techniques dealing with the theoretical description of the influence of zero and reduced gravitational acceleration on diffusion flames, with a view to improving understanding of fires in space vehicles, were developed in support of experimental work performed in this area. This was done in order to confirm qualitative understanding of the process, to determine the quantitative accuracy of numerical predictions, and to establish a mathematical model of the process for subsequent use as a predictive and exploratory tool. The following results were accomplished: (1) derivation of differential equations and boundary conditions describing the system, (2) details of the computations, using a FORTRAN computer program, for calculating the flow and heat and mass transfer in two dimensions (both steady and unsteady). It was shown that the experimental behavior can be reproduced with fair accuracy, provided that the time step is sufficiently short
Video recording true single-photon double-slit interference
As normally used, no commercially available camera has a low-enough dark
noise to directly produce video recordings of double-slit interference at the
photon-by-photon level, because readout noise significantly contaminates or
overwhelms the signal. In this work, noise levels are significantly reduced by
turning on the camera only when the presence of a photon has been heralded by
the arrival, at an independent detector, of a time-correlated photon produced
via parametric down-conversion. This triggering scheme provides the improvement
required for direct video imaging of Young's double-slit experiment with single
photons, allowing clarified versions of this foundational demonstration.
Further, we introduce variations on this experiment aimed at promoting
discussion of the role spatial coherence plays in such a measurement. We also
emphasize complementary aspects of single-photon measurement, where imaging
yields (transverse) position information, while diffraction yields the
transverse momentum, and highlight the roles of transverse position and
momentum correlations between down-converted photons, including examples of
"ghost" imaging and diffraction. The videos can be accessed at
http://sun.iwu.edu/~gspaldin/SinglePhotonVideos.html online.Comment: 7 pages, 8 figure
Psychoative herbs commercialized in streets of Diadema (SP, Brazil): risk in its consumption
O comércio popular de drogas vegetais sem a garantia da qualidade implica em risco sanitário. O presente estudo fez uma análise interdisciplinar da rede de comércio de drogas vegetais (DVs) com foco nas drogas vegetais psicoativas (DVPs), disponíveis no comércio popular da Cidade de Diadema, e os riscos associados ao seu consumo. Métodos da etnofarmacologia, tais como: entrevistas informais, semi-estruturadas e observação participante foram utilizados para a realização do trabalho de campo; durante o qual, selecionaram-se quatro comerciantes, a fim de registrar a obtenção, manipulação, acondicionamento e tipos de DVs comercializadas. Foram registradas 63 DVs que remetiam a atividade psicoativa (DVPs) e, categorizadas em estimulantes (67%), depressoras (27%), depressoras e estimulantes (1%) e finalmente algumas não puderam ser definidas (5%). Essas DVPs tiveram seus nomes populares, forma de preparo e uso, partes utilizadas, contraindicações e doses registradas. Dezoito das 63 DVPs foram selecionadas segundo critérios do estudo, e seus lotes foram adquiridos dos entrevistados, a fim de serem analisados pela microbiologia (61 lotes) e farmacognosia (somente 22 daqueles, referentes a apenas 8 DVPs). Os resultados obtidos por essas áreas, somados a consultas em literaturas científicas, acerca de descrições de reações adversas, serviram de subsídio para a análise final dessas DVPs no contexto da farmacovigilância. Observaram-se deficiências principalmente na manipulação e acondicionamento das DVs por parte dos comerciantes, favorecendo sua contaminação e degradação. Os resultados das análises microbiológicas detectaram que 16% das DVPs analisadas apresentaram populações de bactérias (aeróbias e enterobactérias) superiores a 105 UFC/g e 31%, populações de fungos (bolores e leveduras) superiores a 103 UFC/g e a presença de espécies microbianas indicadoras de risco em 17 DVPs, especificamente em 74% dos 61 lotes, além de fungos produtores de aflatoxinas B1 e/ou B2 em quatro deles. Os resultados da farmacognosia demonstraram que 73% dos lotes foram reprovados ao menos em um dos demais parâmetros analisados (presença de contaminantes, caracterização e perfil cromatográfico). Sendo que, 50% dos 22 lotes analisados não coincidem com as especificações da farmacopéia e 36% apresentaram contaminação por outros órgãos vegetais, superior ao permitido nas monografias e um lote apresentou contaminação por insetos. Todos os 22 lotes foram reprovados na avaliação do rótulo (nomenclatura e validade) e praticamente todas as embalagens foram consideradas inadequadas. Além dos dados obtidos nessas análises, descrições de contra-indicações, efeitos adversos e interações medicamentosas foram encontradas na literatura científica para as 3 DVPs que tiveram sua identidade confirmada pela farmacognosia (camomila, ginkgo biloba e guaraná). Os resultados obtidos nesse estudo possibilitam observar as prioridades de adequação sanitária do comércio popular de DVs, bem como, traçar um perfil da qualidade das DVPs comercializadas segundo os parâmetros analisados. Conclui-se que essas DVPs reúnem importantes fatores capazes de causar danos à saúde dos consumidores, especialmente para alguns grupos como gestantes e indivíduos imunossuprimidos.The popular trade of herbal drugs without quality assurance implies a health risk. This study was an interdisciplinary analysis of the herbal drugs (DVs) trade network with focus on psychoactive drug plant (DVPs) available on the Brazilian city of Diadema, and risks associated with its consumption. Methods of ethnopharmacology, such as informal interviews, semi-structured interviews and participant observation were used for the completion of the fieldwork, during which four tradesmen were selected to register the collection, handling, packaging and types of DVs marketed. We registered 63 DVs that referred to psychoactive activity (DVPs) and categorized as stimulants (67%), depressants (27%), depressants and stimulants (1%) and finally some could not be set (5%). These DVPs had their popular names, preparations and uses, used parts, contraindications, and doses recorded. Eighteen of the 63 DVPs were selected according to the study criteria, and their lots were purchased by the selected tradesmen to be examined by microbiology (61 lots) and Pharmacognosy (only 22 of those lots, related to only 8 DVPs). The results for these areas, together with query in the scientific literature concerning descriptions of adverse reactions, provided the grant for the final analysis of these DVPs in the context of pharmacovigilance. Deficiencies were observed mainly in the handling and packaging of DVs by the traders, favoring its contamination and degradation. The microbiological analysis found that 16% of DVPs analyzed showed populations of bacteria (aerobic and Enterobacteriaceae) exceeding 105 CFU/g and 31%, populations of fungi (molds and yeasts) exceeding 103 CFU/g and the presence of risk indicator microbial species in 17 DVPs, specifically in 74% of the 61 lots, in addition to aflatoxin B1 or B2 producing fungi in four of them. The results of pharmacognosy showed that 73% had failed at least one of the parameters (contaminants, characterization and chromatographic profile), 50% of the 22 lots analyzed did not match the specifications of the pharmacopoeia, 36% were contaminated by other plant organs than those permitted in the monographs and a lot contamination by insects was found. All 22 lots have been disapproved in the evaluation of the label (classification and validity) and virtually all packages were considered inadequate. In addition to data obtained from such analysis, descriptions of contraindications, adverse effects and drug interactions were found in the literature for 3 DVPs who had their identity confirmed by the Pharmacognosy (chamomile, ginkgo biloba and guarana). The results obtained here allow us to observe the priorities of sanitary adequacy of the DVs popular trade, as well as establishing a profile of quality of DVPs marketed according to the analyzed parameters. We conclude that these DVPs gather important factors that could cause damage to the consumers health, especially for some groups such as pregnant women and immunosuppressed individuals.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)TEDEBV UNIFESP: Teses e dissertaçõe
Aerobic exercise training and cardiovascular reactivity to psychological stress in sedentary young normotensive men and women
Abstract Forty-five (22 women) sedentary young (18-30 years old) nonsmoking normotensive volunteers engaged in either 6 weeks of aerobic training (AT), weight training (WT), or a no-treatment (NT) condition to determine whether AT lowers systolic (SBP) and diastolic (DBP) blood pressure, heart rate (HR), and rate-pressure product (RPP) during rest, psychological stress, and recovery periods. Estimated VO 2 max increased for the AT (32.1 AE 1.1 to 38.4 AE 1.0 ). A smaller increase for the WT (30.5 AE 1.1 to 33.8 AE 1.0) was likely due to increased leg strength, and VO 2 max did not change for the NT (32.5 AE 1.1 to 32.9 AE 1.0). Heart rate and RPP levels were lower during psychological stress and recovery after training for AT relative to the WT and NT. Overall SBP was also lower in the AT relative to the NT but not the WT. In conclusion, aerobic training lowered cardiovascular activity levels during psychological stress and recovery in healthy young adults, implying a protective role against age-related increases in coronary heart disease for individuals who adopt aerobic exercise early in life and maintain the behavior across the life span
Serum S100A8/A9 and S100A12 Levels in Children With Polyarticular Forms of Juvenile Idiopathic Arthritis: Relationship to Maintenance of Clinically Inactive Disease During Anti–Tumor Necrosis Factor Therapy and Occurrence of Disease Flare After Discontinuation of Therapy
© 2018, American College of Rheumatology Objective: To determine the relationship between serum levels of S100A8/A9 and S100A12 and the maintenance of clinically inactive disease during anti–tumor necrosis factor (anti-TNF) therapy and the occurrence of disease flare following withdrawal of anti-TNF therapy in patients with polyarticular forms of juvenile idiopathic arthritis (JIA). Methods: In this prospective, multicenter study, 137 patients with polyarticular-course JIA whose disease was clinically inactive while receiving anti-TNF therapy were enrolled. Patients were observed for an initial 6-month phase during which anti-TNF treatment was continued. For those patients who maintained clinically inactive disease over the 6 months, anti-TNF was withdrawn and they were followed up for 8 months to assess for the occurrence of flare. Serum S100 levels were measured at baseline and at the time of anti-TNF withdrawal. Spearman\u27s rank correlation test, Mann-Whitney U test, Kruskal-Wallis test, receiver operating characteristic (ROC) curve, and Kaplan-Meier survival analyses were used to assess the relationship between serum S100 levels and maintenance of clinically inactive disease and occurrence of disease flare after anti-TNF withdrawal. Results: Over the 6-month initial phase with anti-TNF therapy, the disease state reverted from clinically inactive to clinically active in 24 (18%) of the 130 evaluable patients with polyarticular-course JIA; following anti-TNF withdrawal, 39 (37%) of the 106 evaluable patients experienced a flare. Serum levels of S100A8/A9 and S100A12 were elevated in up to 45% of patients. Results of the ROC analysis revealed that serum S100 levels did not predict maintenance of clinically inactive disease during anti-TNF therapy nor did they predict disease flare after treatment withdrawal. Elevated levels of S100A8/A9 were not predictive of the occurrence of a disease flare within 30 days, 60 days, 90 days, or 8 months following anti-TNF withdrawal, and elevated S100A12 levels had a modest predictive ability for determining the risk of flare within 30, 60, and 90 days after treatment withdrawal. Serum S100A12 levels at the time of anti-TNF withdrawal were inversely correlated with the time to disease flare (r = −0.36). Conclusion: Serum S100 levels did not predict maintenance of clinically inactive disease or occurrence of disease flare in patients with polyarticular-course JIA, and S100A12 levels were only moderately, and inversely, correlated with the time to disease flare
Structure of the near-injector region of nonevaporating pressure-atomized sprays
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76883/1/AIAA-23315-239.pd
Structure of turbulent sonic underexpanded free jets
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76109/1/AIAA-10145-898.pd
Measurement of the Strong Coupling Constant from Inclusive Jet Production at the Tevatron Collider
We report a measurement of the strong coupling constant, ,
extracted from inclusive jet production in collisions at
1800 GeV. The QCD prediction for the evolution of with
jet transverse energy is tested over the range 40<<450 GeV using
for the renormalization scale. The data show good agreement with QCD in
the region below 250 GeV. In the text we discuss the data-theory comparison in
the region from 250 to 450 GeV. The value of at the mass of the
boson averaged over the range 40<<250 GeV is found to be
. The associated theoretical uncertainties are mainly due to the choice
of renormalization scale (^{+6%}_{-4%}) and input parton distribution
functions (5%).Comment: 7 pages, 3 figures, using RevTeX. Submitted to Physical Review
Letter
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