2,891 research outputs found

    Ionosphere Investigations

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    Review of ionospheric research studies and impact of studies on understanding radio communications and solar terrestrial relationship

    Labor Relations in Public Employment - Can Government Govern Itself?

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    Investigation of nonlinear E.M. phenomena in the tethered magnetospheric cloud

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    Nonlinear effects of parametric and of heating type, produced in a plasma under the action of an electric field E(sub 0)(e exp i(omega)t), are considered in this work in connection with the Tethered Magnetospheric Cloud (TMC) accompanying the Tether Satellite System (TSS). The theoretical results show that these phenomena should appear in the ionosphere at high altitudes Z greater than or = (150-200) km, particularly, at Z approximately = 300 km of the TSS system orbit. Therefore, it is of a special interest to search these phenomena by such a unique experiment as the forthcoming first TSS-I and by the future, perhaps modified TSS missions. Because of the parametric decay instability, new branches of wave may be excited both around the electron and ion Lengmuir frequencies Omega (sub 0) = 2(pi)f(sub 0) and Omega (sub 0) = 2(pi)f(sub 0) under the influence of high frequency (HF), (f less than or = 10(exp 6) to few 10(exp 6) Hz), strong electric waves. The heating of all the kinds of particles is growing up very quickly in the ionosphere with altitude in the extra low and very low frequency ranges, F approximately = (1 to 10(exp 4) Hz, discussed below. The temperatures (energies), for example, of the electrons accelerated by the electric field become larger than the ionization potential in this frequency range already at altitudes Z greater than or = (150 - 200) km when the amplitude of the electric field is the absolute value of E(sub 0) approximately = (1-2) mV/m. The sources of these electric fields may be in the TSS-I mission, that so called Phantom Loop (PL) - the Tethered Electrodynamic Tail (TET), and the different kind of electromagnetic oscillations produced by different kinds of instabilities in the TMC plasma. The growth rates of these instabilities will become very high in the TSS surrounding magnetoplasma. However, in the future TSS missions, special artificial sources (generators) of electric fields should be used for these investigations

    Investigation of the structure of the electromagnetic field and related phenomena, generated by the Active Satellite

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    The altitude dependencies of the moduli of the electric field E in the VLF and LF frequency bands (f sub B much less than F less than f sub B) and in the altitude range of the ionosphere Z equals (400 to 2500) km up to Z equals 6000 km (the bottom of the magnetosphere) were calculated by the linear theory. The amplitudes of the field have large maxima in four regions: the axis field (E sub o) close to the direction of the Earth's magnetic field line B sub o, beta approximately 0 degrees, the fields (E sub St), (E sub RevSt) and (E sub Res) in the Storey, Reversed Story and Resonance cones, beta approximately (0 approaches 20) degrees. Their maxima are very pronounced close to the low hybrid frequency F sub L. The nonlinear heating of the magnetoplasma under the action of an electric field Ee (sup iwt) was recently expanded by the macroscopic theory by the author. The velocities, collision frequencies and temperatures of all the constituents of a magnetoplasma - electrons, ions, and neutral particles - are taken into account. Formulae and numerical results are presented for the ionosphere in the frequency band F equals (1 to 10 exp 4) kHz and altitude range Z approximately (100 - 1000) km. Some results of calculations by the self consistent solution of the basis system of equations are also discussed

    The Paper Trail: An Arid Connection & A Book of a Thousand Plants

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    Following my Ph.D., I moved on to Nebraska, where as a beginning faculty member I was able to start a research program in ecology and continue to study what intrigued me most: plant competition and stress. It was during this time that I came across the paper by Peter Alpert (see his article below) and his colleagues on “Invasiveness, invasibility, and the role of environmental stress in preventing the spread of non-native plants” (Perspectives in Plant Ecology, Evolution and Systematics 3:52–66). It was an “aha” moment in reading about biological invasion research and the current consensus at that time regarding invasiveness and invasibility in plant species and communities. I had seen first-hand or at least I had thought about things like nonnatives remaining noninvasive for long periods, the relationship between plasticity and invasiveness, and the “unlike invader” hypothesis, which were all touched on in the paper. Add to this the discussion on the topic of stress (e.g., drought) affecting invasibility and the conceptual diagrams showing hypothetical responses of native and nonnatives under minimum and maximum levels, and I was convinced that my ideas were similar to those of others. For the first time, I did not feel alone in my thinking. In a way, it was a newfound freedom that allowed me to ponder more deeply the effects of stress on invasive plants. Extreme drought is a type of stress or selection pressure imposed on plants and communities of plants that can reveal fitness and plasticity differences that if understood could have profound impacts on invasion and community assembly theory

    Metabolic syndrome: Differences for Asian Americans is in their percentage of body fat

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    Asian Americans are not frequently thought of as being obese or overweight yet some of the Asian American subgroups have a disproportionate risk for cardiovascular disease and type 2 diabetes mellitus. Although the standardized body mass index (BMI) assessment is an adequate tool for reporting secular prevalence trends for overweight/obesity across populations, it falls short in accuracy when assessing Asian Americans. In recent years more has been written about the re-evaluation of BMI cut points for normal weight, overweight, or obese Asian Americans. Additionally, the waist circumference norm was modified to indicate a smaller waist size is a risk for metabolic syndrome. The purpose of this paper is to provide an overview of the research literature on BMI and percentage of body fat as it relates to health risk for metabolic syndrome for Asian American subgroups. Three databases were used to identify articles for this review: Google Scholar, CINHAL, and PubMed. Seven hundred twenty-six articles were initially identified as meeting the criteria; 690 articles were eliminated after a review of the article titles revealed the content did not meet the focus of this review. Of the remaining articles, 19 were eliminated after a review of the abstracts indicated they were meta-analyses, review articles, or case studies. The remaining 18 articles were included in this review. Three common themes emerged. (1) The differences in BMI and body fat percentage are evident between Asian Americans and other ethnic groups. (2) Differences in the percentage of body fat exist between Asian American subgroups, and between Asian Americans and Asian immigrants. (3) There are differences in disease development end points when comparing Asian American subgroups and Asian immigrant subgroups. There are differences in body fat distribution and body fat percentages as well as BMI compared to other ethnic groups for metabolic syndrome. There are also differences between Asian immigrant/Asian American subgroups whereby some are more susceptible to diabetes and cardiovascular disease. Research is necessary to determine if these differences have an underlying genetic predisposition. Additionally, researchers need to oversample Asian immigrant/Asian American participants in comparison studies and need to identify each subgroup in their research rather than aggregating Asian immigrants/Asian Americans by geographical origin or as one common group designated as a generic group of “Asians.

    The Hurricane : March-Two Step

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    https://digitalcommons.library.umaine.edu/mmb-ps/2347/thumbnail.jp
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