133 research outputs found
Semiconductor Surface Studies
Contains an introduction, reports on two research projects and a list of publications.Joint Services Electronics Program Contract DAAL03-92-C-0001Joint Services Electronics Program Grant DAAH04-95-1-003
Semiconductor Surface Studies
Contains an introduction, reports on two research projects and a list of publications.Joint Services Electronics Program Contract DAAL03-92-C-000
The oxidative metabolism of sparteine in the Cuna Amerindians of Panama: Absence of evidence for defient metabolizers
ArtĂculo cientĂfico -- Universidad de Costa Rica. Instituto de Investigaciones en Salud, 1988Sparteine sulfate (50 mg) was administered to 170 Cuna Amerindians, 142 of whom were unrelated, and the drug and its dehydrometabolites were determined in the 0- to 12-hour urine samples. The log10 of the metabolic ratio was unimodally, but not normally, distributed and showed the following values: mean 0.21 ± 0.26, median 0.24, limits 0.73 and 0.76, skewness 1.00, and kurtosis 4.95. On the basis of these results, it can be concluded that there are no deficient metabolizers in the Cuna sample population studied. However, the similarity of the skewness found between the Cuna sample population studied and the extensive Canadian white group, as well as an inflection point at 6.3 U in the former's probit plot, suggests the existence of at least two subgroups congregating within the same single mode in the frequency distribution curve. The use of the inflection point is discussed thoroughly, concluding that although it does not allow exclusion of the existence of genotypically different subgroups, the limitations of the data do not permit its use to determine the number of heterozygotes and thus the existence of polymorphism. The possibility of an isozyme variant, consistent with the general genetic structure of Amerindians, as suggested by the coexistence of two subgroups within the unimodal curve, is entertained. (CLIN PHARmAcoL THER 1988;43:456-65.)Universidad de Costa Rica. Instituto de Investigaciones en Salud.Universidad de PanamĂĄUniversidad de TorontoUCR::VicerrectorĂa de InvestigaciĂłn::Unidades de InvestigaciĂłn::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA
Semiconductor Surface Studies
Contains an introduction, reports on two research projects and a list of publications.Joint Services Electronics Program Contract DAALO3-92-C-000
Semiconductor Surface Studies
Contains an introduction and reports on two research projects.Joint Services Electronics Program Contract DAAL03-89-C-000
Semiconductor Surface Studies
Contains research summary and reports on two research projects.Joint Services Electronics Program (Contract DAAL03-86-K-0002)Joint Services Electronics Program (Contract DAAL03-89-C-0001
A Low Dose of Dietary Resveratrol Partially Mimics Caloric Restriction and Retards Aging Parameters in Mice
Resveratrol in high doses has been shown to extend lifespan in some studies in invertebrates and to prevent early mortality in mice fed a high-fat diet. We fed mice from middle age (14-months) to old age (30-months) either a control diet, a low dose of resveratrol (4.9 mg kgâ1 dayâ1), or a calorie restricted (CR) diet and examined genome-wide transcriptional profiles. We report a striking transcriptional overlap of CR and resveratrol in heart, skeletal muscle and brain. Both dietary interventions inhibit gene expression profiles associated with cardiac and skeletal muscle aging, and prevent age-related cardiac dysfunction. Dietary resveratrol also mimics the effects of CR in insulin mediated glucose uptake in muscle. Gene expression profiling suggests that both CR and resveratrol may retard some aspects of aging through alterations in chromatin structure and transcription. Resveratrol, at doses that can be readily achieved in humans, fulfills the definition of a dietary compound that mimics some aspects of CR
Conceptual design of the International Axion Observatory (IAXO)
The International Axion Observatory (IAXO) will be a forth generation axion
helioscope. As its primary physics goal, IAXO will look for axions or
axion-like particles (ALPs) originating in the Sun via the Primakoff conversion
of the solar plasma photons. In terms of signal-to-noise ratio, IAXO will be
about 4-5 orders of magnitude more sensitive than CAST, currently the most
powerful axion helioscope, reaching sensitivity to axion-photon couplings down
to a few GeV and thus probing a large fraction of the
currently unexplored axion and ALP parameter space. IAXO will also be sensitive
to solar axions produced by mechanisms mediated by the axion-electron coupling
with sensitivity for the first time to values of not
previously excluded by astrophysics. With several other possible physics cases,
IAXO has the potential to serve as a multi-purpose facility for generic axion
and ALP research in the next decade. In this paper we present the conceptual
design of IAXO, which follows the layout of an enhanced axion helioscope, based
on a purpose-built 20m-long 8-coils toroidal superconducting magnet. All the
eight 60cm-diameter magnet bores are equipped with focusing x-ray optics, able
to focus the signal photons into cm spots that are imaged by
ultra-low-background Micromegas x-ray detectors. The magnet is built into a
structure with elevation and azimuth drives that will allow for solar tracking
for 12 h each day.Comment: 47 pages, submitted to JINS
Current commands for high-efficiency torque control of DC shunt motor
The current commands for a high-efficiency torque control of a DC shunt motor are described. In the proposed control method, the effect of a magnetic saturation and an armature reaction are taken into account by representing the coefficients of an electromotive force and a torque as a function of the field current, the armature current and the revolving speed. The current commands at which the loss of the motor drive system becomes a minimum are calculated as an optimal problem. The proposed control technique of a motor is implemented on the microprocessor-based control system. The effect of the consideration of the magnetic saturation and the armature reaction on the produced torque and the minimisation of the loss are discussed analytically and experimentally </p
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