320 research outputs found
Equatorial X-rays and their effect on the lower mesosphere
On the night of May 23/24, 1975, a sequence of rocket and balloon experiments was launched from Chilca Base, Peru (12.5 deg S, 76.8 deg W, magnetic dip = - 0.7 deg). Detailed analysis and comparisons of the data yielded the first direct measurement of lower mesospheric response to a galactic X-ray source. This result could only have been determined at the equator, where cosmic ray background effects are minimal. The objective of the experiments was to seek out the equatorial energetic electron belt, sporadically reported to contain fluxes near auroral levels, measure the bremsstrahlung radiation produced by this particle belt, and determine the influence of this radiation on the middle atmosphere. High altitude rocket payloads (Nike Tomahawk 18.170 and 18.171) were launched to probe the thermosphere during and following the anticipated downward drift period. Each carried an on-axis X-ray scintillation detector and Geiger Mueller energetic electron detectors. Magnetometers and lunar sensors were used to determine payload aspect
Smash products for secondary homotopy groups
We construct a smash product operation on secondary homotopy groups yielding
the structure of a lax symmetric monoidal functor. Applications on cup-one
products, Toda brackets and Whitehead products are considered. In particular we
prove a formula for the crossed effect of the cup-one product operation on
unstable homotopy groups of spheres which was claimed by
Barratt-Jones-Mahowald.Comment: We give a clearer description of the tensor product of symmetric
sequences of quadratic pair module
Survey of Community Knowledge, Attitudes, and Practices During a Malaria Epidemic in Central Java, Indonesia
We surveyed adults in a randomly selected sample of 1,000 households in 50 villages in nine malarial sub-districts in Purworejo, central Java, Indonesia from May to July 2001. The survey assessed malaria knowledge, attitudes, and practices in communities experiencing epidemic malaria to begin exploring broad strategies for controlling the disease in the region. A pre-tested survey instrument consisting of 93 questions addressed demographic characteristics, socioeconomic factors, knowledge and perceptions of malaria, burden and severity of disease, treatment-seeking behavior, malaria prevention practices, and perceptions of government malaria control efforts. The survey was taken by in-person interview of all subjects. Most (97%) subjects were aware of malaria and more than two-thirds correctly identified mosquitoes as the vector. Forty-one percent of households in both forest/hilly and agricultural/urban areas reported malaria illness in the past year. Thirty-six percent (357 households) owned at least one bed net, 92% of these had been purchased by the owners. However, only 36% of households with bed nets affirmed their use as a means of preventing malaria. Nearly all respondents reported a willingness to accept spraying of residual insecticides for malaria prevention, yet less than 5% were willing to pay a nominal fee (US $3) for this service. Fifty-two percent of respondents reported self-treatment of malaria illness without visiting a health facility. This assessment of knowledge, attitudes, and practices showed a broad awareness of malaria and its consequences among residents of malarial areas in the Menoreh Hills of Central Java
Malaria in a cohort of Javanese migrants to Indonesian Papua
The epidemiology of infection by Plasmodium falciparum and P. vivax was investigated among Javanese migrants to an endemic region of Papua, Indonesia. A cohort of 243 migrants from Java was followed for malaria in a new settlement village in the endemic Armopa area of north–eastern Papua, beginning on the day each migrant arrived in the village. The subjects were monitored during home visits (three/week) and by the twice-monthly production of bloodsmears that were checked for malarial parasites. At the end of 33 months, 159 (65%) of the subjects remained under follow-up. The prevalence of parasitaemia in the village declined from 16% among those already living there when the study began in August 1996, to 5% when the study finished in June 1999. Over this period, 596 infections by P. falciparum and 723 by P. vivax occurred in the cohort, 22 and 27 of the subjects each experiencing at least six infections by P. falciparum and P. vivax, respectively. The incidence of malarial infection was higher during the first and second years post-migration (3.2 and 2.7 infections/person-year) than during the third (1.2 infections/person-year). Although the geometric mean parasite counts for P. falciparum increased over time (1209, 1478, and 1830 parasites/ml in the first, second and third years, respectively), the corresponding values for P. vivax (497, 535 and 490 parasites/ml ) showed no such trend. Only one of the nine subjects who developed severe malaria (requiring intravenous quinine therapy) was a child, giving an odds ratio for a case of severe malaria being in an adult of 6.1 (P=0.08)
Production and validation of durable, high quality standardized malaria microscopy slides for teaching, testing and quality assurance during an era of declining diagnostic proficiency
Background: Sets of Giemsa-stained, blood smear slides with systematically verified composite diagnoses would contribute substantially to development of externally validated quality assurance systems for the microscopic diagnosis of malaria.
Methods: whole blood from Plasmodium-positive donors in Cambodia and Indonesia and individuals with no history of risk for malaria was collected. Using standard operating procedures, technicians prepared Giemsastained thick and thin smears from each donor. One slide from each of the first 35 donations was distributed to each of 28 individuals acknowledged by reputation as having expertise in the microscopic diagnosis of malaria. These reference readers recorded presence or absence of Plasmodium species and parasite density. A composite diagnosis for each donation was determined based on microscopic findings and species-specific small subunit ribosomal RNA (ssrRNA) DNA polymerase chain reaction (PCR) amplification.
Results: More than 12, 000 slides were generated from 124 donations. Reference readers correctly identified presence of parasites on 85% of slides with densities \u3c100 parasites/μl, which improved to 100% for densities \u3e350 parasites/μl. Percentages of agreement with composite diagnoses were highest for Plasmodium falciparum (99%), followed by Plasmodium vivax (86%).
Conclusion: Herein, a standardized method for producing large numbers of consistently high quality, durable Giemsa-stained blood smears and validating composite diagnoses for the purpose of creating a malaria slide repository in support of initiatives to improve training and competency assessment amidst a background of variability in diagnosis is described
Severe Vivax Malaria: Newly Recognised or Rediscovered?
Stephen Rogerson and Richard Carter discuss two new studies that challenge current dogma by suggesting that vivax malaria can cause severe disease
Measurement of the Nucleon F\u3csup\u3en\u3c/sup\u3eâ‚‚/F\u3csup\u3ep\u3c/sup\u3eâ‚‚ Structure Function Ratio by the Jefferson Lab MARATHON Tritium/Helium-3 Deep Inelastic Scattering Experiment
The ratio of the nucleon F2 structure functions, Fn2/Fp2, is determined by the MARATHON experiment from measurements of deep inelastic scattering of electrons from 3H and 3He nuclei. The experiment was performed in the Hall A Facility of Jefferson Lab using two high-resolution spectrometers for electron detection, and a cryogenic target system which included a low-activity tritium cell. The data analysis used a novel technique exploiting the mirror symmetry of the two nuclei, which essentially eliminates many theoretical uncertainties in the extraction of the ratio. The results, which cover the Bjorken scaling variable range 0.19 \u3c x \u3c 0.83, represent a significant improvement compared to previous SLAC and Jefferson Lab measurements for the ratio. They are compared to recent theoretical calculations and empirical determinations of the Fn2/Fp2 ratio
Density Changes in Low Pressure Gas Targets for Electron Scattering Experiments
A system of modular sealed gas target cells has been developed for use in
electron scattering experiments at the Thomas Jefferson National Accelerator
Facility (Jefferson Lab). This system was initially developed to complete the
MARATHON experiment which required, among other species, tritium as a target
material. Thus far, the cells have been loaded with the gas species 3H, 3He,
2H, 1H and 40Ar and operated in nominal beam currents of up to 22.5 uA in
Jefferson Lab's Hall A. While the gas density of the cells at the time of
loading is known, the density of each gas varies uniquely when heated by the
electron beam. To extract experimental cross sections using these cells,
density dependence on beam current of each target fluid must be determined. In
this study, data from measurements with several beam currents within the range
of 2.5 to 22.5 uA on each target fluid are presented. Additionally, expressions
for the beam current dependent fluid density of each target are developed.Comment: 8 pages, 12 figures, 4 table
Argentina. Sello Alimentos Argentinos
Resumen Alimentos Argentinos es un sello de calidad que distingue los alimentos argentinos y sus atributos diferenciadores –proceso, producto y envase-. Es gratuito, temporal, voluntario y puede ser solicitado por productores y/o elaboradores de alimentos, que cumplan con el Protocolo correspondiente. El cumplimiento a dichos protocolos es auditado por terceros independientes, habilitados para tal fin.Fil: Pighin, DarÃo Gabriel. Instituto Nacional de TecnologÃa Agropecuaria (INTA). CIA. Instituto TecnologÃa de Alimentos; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas (CONICET); Argentina. Universidad de Morón; Argentina.Fil: Tam, C. Ministerio de Producción y Trabajo. SecretarÃa de Gobierno de Agroindustria; Argentina.Fil: Pazos, Adriana Alejandra. Instituto Nacional de TecnologÃa Agropecuaria (INTA). CIA. Instituto TecnologÃa de Alimentos; Argentina. Universidad de Morón; Argentina.Fil: Barcus, M. C. Ministerio de Producción y Trabajo. SecretarÃa de Gobierno de Agroindustria; Argentina.Fil: Moron, J. M. Ministerio de Producción y Trabajo. SecretarÃa de Gobierno de Agroindustria; Argentina.Fil: Moron, P. H. Ministerio de Producción y Trabajo. SecretarÃa de Gobierno de Agroindustria; Argentina.Fil: Nimo, M. Ministerio de Producción y Trabajo. SecretarÃa de Gobierno de Agroindustria; Argentina.Fil: Grigioni, Gabriela Maria. Instituto Nacional de TecnologÃa Agropecuaria (INTA). CIA. Instituto TecnologÃa de Alimentos; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas (CONICET); Argentina. Universidad de Morón; Argentina
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