157 research outputs found

    Isotopic and elemental composition of the anomalous low-energy cosmic-ray fluxes

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    Recent observations of cosmic rays below ~30 MeV nucleon^(-1) have revealed anomalous enhancements in the energy spectra of oxygen, nitrogen, and helium relative to those of other nuclei such as boron and carbon. We have measured the quiet-time fluxes of the elements hydrogen through oxygen in the ~4-30 MeV nucleon^(-1) energy interval during the period 1972 October through 1974 October. We find that the low-energy fluxes of Li, Be, B, and Care consistent with those expected from adiabatic deceleration and show no significant evidence for secondary fragmentation products arising from the enhanced nitrogen and oxygen fluxes. In the ~6-12 MeV nucleon^(-1) interval, the observed nitrogen and oxygen nuclei are predominantly ^(14)N and ^(16)O, with upper limits (84% confidence level) of ^(15)N/N ≤ 0.26, ^(17)O/O ≤ 0.13, and ^(18)O/O ≤ 0.12 for the other stable nitrogen and oxygen isotopes. These isotopic measurements are consistent with the presumed isotopic composition of the neutral interstellar medium, as would be the case if the anomalous component is locally accelerated. If, on the other hand, the enhanced low-energy cosmic rays result from unusual nucleosynthesis processes which enhance nitrogen and oxygen but not carbon, then these processes are constrained to producing predominantly ^(14)N and ^(16)O

    The Elemental Composition of 4-30 MeV/nuc Cosmic Ray Nuclei with 1 ≤ Z ≤ 8

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    Recent observations of low energy cosmic rays have shown enhanced fluxes of nitrogen and oxygen relative to other elements in the ~8-30 MeV/nuc energy interval. We have extended the measurements of lithium through oxygen down to ~ 4 MeV/nuc with the Caltech Electron/Isotope Spectrometers on IMP-7 and -8 during solar quiet periods from October 1972 to September 1974. We find no evidence for significant enhancements of Li, Be, B. or C, which are found to have energy spectra consistent with those expected from the adiabatic deceleration of higher energy galactic cosmic rays. The He, N, and O fluxes are greatly enhanced when compared to the other elements, with relative abundances of O/He ~ 0.25, O/B ~ 100, and O/C ~ 30 at ~ 5 to 12.5 MeV/nuc

    Isotopic Composition of the Anomalous Low Energy Cosmic Ray Nitrogen and Oxygen

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    The isotopic composition of the enhanced fluxes of cosmic ray nitrogen and oxygen observed below 30 MeV/nuc is of interest, whether the nuclei are a sample from some nearby galactic source region that is underabundant in carbon, or a sample of the neutral interstellar medium. Enhanced fluxes in the 6 to 12 MeV/nuc energy interval were measured over a two year period with the Caltech Electron/Isotope Spectrometer on IMP-7. The observed low-energy nitrogen and oxygen nuclei are predominantly N-14 and O-16, with upper limits (84% confidence level) of N-15/N below 0.26, O-17/0 below 0.13, and O-18/0 below 0.12 for other isotopes in the 6-12 MeV/nuc energy interval. The implications of these results for the origin of the enhanced nitrogen and oxygen fluxes are discussed

    Quality evaluation of minoxidil topical solutions obtained from magistral pharmacies

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    The objective of this study was to evaluate quality parameters of magistral topical solutions containing minoxidil (A, B and C), comparing the results with the ones obtained for the industrial formulation. Organoleptic tests, evaluation of the pH and density, centrifuge test, drug content determination, comparison of indicated dosages and in vitro follicular penetration of minoxidil were performed. Regarding the organoleptic properties, differences in color and viscosity were observed between the magistral (composed of minoxidil sulfate) and the industrial formulations (composed of minoxidil base). For pH values, the magistral solutions presented considerably more acidic pH, compared to the industrial sample. For the density test, the samples with the highest ethanol percentages (B and C) presented lower density. In the centrifuge test, none of the samples showed changes. Considering the drug content test, only the industrial sample and the magistral sample C showed drug percentage within the expected (90-110%), indicating lack of correction factor determination by the magistral pharmacies. Furthermore, it was observed that the dosage indicated by the magistral pharmacies do not correspond to the dose indicated by the industry, being significantly lower. All topical solutions tested presented hair follicle penetration of minoxildil, without statistical difference. The results indicate that there is a failure in the magistral pharmacies regarding the production and the indication of dosage of minoxidil topical solutions

    Ensaio para determinação do valor de cultivo e uso em populações de trevo-vesiculoso (Trifolium vesiculosum Savi).

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    O objetivo esta publicação é avaliar a produtividade de materiais de trevo-vesiculoso desenvolvidos pelo programa de Melhoramento de Leguminosas Forrageiras de Clima Temperado da Embrapa

    Rendimento de matéria seca e folhas de genótipos de Lolium multiflorum.

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    Este trabalho teve como objetivo avaliar e comparar a produtividade de matéria seca foliar e matéria seca total de nove cultivares brasileiras de Lolium multiflorum

    Produtividade de forragem de genótipos de trevo-persa em terras baixas.

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    O objetivo deste trabalho foi avaliar a produtividade de materiais de trevo-persa desenvolvidos pelo programa de Melhoramento de Leguminosas Forrageiras de Clima Temperado da Embrapa

    Melioidosis Vaccines: A Systematic Review and Appraisal of the Potential to Exploit Biodefense Vaccines for Public Health Purposes

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    The designation of Burkholderia pseudomallei as a category B select agent has resulted in considerable research funding to develop a protective vaccine. This bacterium also causes a naturally occurring disease (melioidosis), an important cause of death in many countries including Thailand and Australia. In this study, we explored whether a vaccine could be used to provide protection from melioidosis. An economic evaluation based on its use in Thailand indicated that a vaccine could be a cost-effective intervention if used in high-risk populations such as diabetics and those with chronic kidney or lung disease. A literature search of vaccine studies in animal models identified the current candidates, but noted that models failed to take account of the common routes of infection in natural melioidosis and major risk factors for infection, primarily diabetes. This review highlights important areas for future research if biodefence-driven vaccines are to play a role in reducing the global incidence of melioidosis
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