7,030 research outputs found

    Solar wind data from the MIT plasma experiments on Pioneer 6 and Pioneer 7

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    Hourly averages are presented of solar wind proton parameters obtained from experiments on the Pioneer 6 and Pioneer 7 spacecraft during the period December 16, 1965 to August 1971. The number of data points available on a given day depends upon the spacecraft-earth distance, the telemetry bit rate, and the ground tracking time allotted to each spacecraft. Thus, the data obtained earlier in the life of each spacecraft are more complete. The solar wind parameters are given in the form of plots and listings. Trajectory information is also given along with a detailed description of the analysis procedures used to extract plasma parameters from the measured data

    Failure mechanisms and surface roughness statistics of fractured Fontainebleau sandstone

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    In an effort to investigate the link between failure mechanisms and the geometry of fractures of compacted grains materials, a detailed statistical analysis of the surfaces of fractured Fontainebleau sandstones has been achieved. The roughness of samples of different widths W is shown to be self affine with an exponent zeta=0.46 +- 0.05 over a range of length scales ranging from the grain size d up to an upper cut-off length \xi = 0.15 W. This low zeta value is in agreement with measurements on other sandstones and on sintered materials. The probability distributions P(delta z,delta h) of the variations of height over different distances delta z > d can be collapsed onto a single Gaussian distribution with a suitable normalisation and do not display multifractal features. The roughness amplitude, as characterized by the height-height correlation over fixed distances delta z, does not depend on the sample width, implying that no anomalous scaling of the type reported for other materials is present. It is suggested, in agreement with recent theoretical work, to explain these results by the occurence of brittle fracture (instead of damage failure in materials displaying a higher value of zeta = 0.8).Comment: 7 page

    Goitre and Iodine Deficiency in Europe

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    The prevalence of endemic iodine-deficiency goitre in Europe has been reduced in many areas by the introduction of iodination programmes. Recent reports, however, show that goitre remains a significant problem and that its prevalence has not decreased in a number of European countries. Hetzel1 has pointed out that the high global prevalence of iodine-deficiency disorders could be eradicated within 5-10 years by introduction of an iodised salt programme. The current World Health Organisation recommendations for iodine intake are between 150 and 300 μg/da

    Interaction of the solar wind with Venus

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    Two topics related to the interaction of the solar wind with Venus are considered. First, a short review of the experimental evidence with particular attention to plasma measurements carried out on Mariner-5 and Mariner-10 is given. Secondly, the results of some recent theoretical work on the interaction of the solar wind with the ionosphere of Venus are summarized

    Timing of a Young Mildly Recycled Pulsar with a Massive White Dwarf Companion

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    We report on timing observations of the recently discovered binary pulsar PSR J1952+2630 using the Arecibo Observatory. The mildly recycled 20.7-ms pulsar is in a 9.4-hr orbit with a massive, M_WD > 0.93 M_sun, white dwarf (WD) companion. We present, for the first time, a phase-coherent timing solution, with precise spin, astrometric, and Keplerian orbital parameters. This shows that the characteristic age of PSR J1952+2630 is 77 Myr, younger by one order of magnitude than any other recycled pulsar-massive WD system. We derive an upper limit on the true age of the system of 50 Myr. We investigate the formation of PSR J1952+2630 using detailed modelling of the mass-transfer process from a naked helium star on to the neutron star following a common-envelope phase (Case BB Roche-lobe overflow). From our modelling of the progenitor system, we constrain the accretion efficiency of the neutron star, which suggests a value between 100 and 300% of the Eddington accretion limit. We present numerical models of the chemical structure of a possible oxygen-neon-magnesium WD companion. Furthermore, we calculate the past and the future spin evolution of PSR J1952+2630, until the system merges in about 3.4 Gyr due to gravitational wave emission. Although we detect no relativistic effects in our timing analysis we show that several such effects will become measurable with continued observations over the next 10 years; thus PSR J1952+2630 has potential as a testbed for gravitational theories.Comment: 12 pages, 10 figures, to be published in MNRA

    Process evaluation for stressor reduction interventions in sport

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    Stressor reduction interventions may have the potential to improve the well-being of those involved in sport. Organizational psychologists have used these primary interventions in various performance domains. The authors describe the stressor reduction design and implementation processes, and the contexts in which they occur, that impact on these interventions. The authors then examine how process evaluation methods can be applied during stressor reduction in sport settings. Process evaluation requires the frequent collection of data about intervention experiences and events from multiple sources using a mixed-methods approach. The article contains practical recommendations for sport psychologists who implement stressor reduction interventions

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74659/1/j.1365-2648.1990.tb01950.x.pd

    A satisfação vital: sua relação com o preconceito, a identidade nacional, a autoestima e o bem-estar material, em imigrantes

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    El propósito de esta investigación fue estudiar la relación de la satisfacción vital con varios factores psicosociales corrientemente vinculados a los procesos de migración internacional. En concreto, este estudio exploró la relación de la satisfacción vital - componente cognitivo del bienestar subjetivo - con las variables prejuicio grupal percibido, discriminación personal percibida, autoestima global personal, identidad nacional y bienestar material percibido. La investigación, de tipo empírico y cuantitativo, se realizó a través de un muestreo no probabilístico con inmigrantes colombianos en varias ciudades del Ecuador (N = 185). Confirmando las hipótesis, se halló una relación positiva entre la satisfacción vital, el bienestar material percibido y la autoestima. Se confirmó así mismo una relación negativa entre la satisfacción vital, la discriminación personal percibida y la identidad nacional. Estas mismas variables; la autoestima, el bienestar material percibido, la discriminación personal percibida y la identidad nacional, emergieron como predictoras de la satisfacción vital. No se confirmó, en cambio, la relación negativa hipotetizada entre la satisfacción vital y el prejuicio grupal percibido. Se hace un análisis de dichos resultados desde la literatura psicosocial.O propósito desta pesquisa foi estudar a relação da satisfação vital com vários fatores psicossociais correntemente vinculados aos processos de migração internacional. Em concreto, este estudo explorou a relação da satisfação vital - componente cognitivo do bem-estar subjetivo - com as variáveis preconceito grupal percebido, discriminação pessoal percebida, autoestima global pessoal, identidade nacional e bem-estar material percebido. A pesquisa, de tipo empírica e quantitativa, foi realizada através de um amostra não probabilística com imigrantes colombianos em várias cidades do Equador (N = 185). Confirmando as hipóteses, foi encontrada uma relação positiva entre a satisfação vital, o bem-estar material percebido e a autoestima. Foi confirmada assim uma relação negativa entre a satisfação vital, a discriminação pessoal percebida e a identidade nacional. Estas mesmas variáveis; a autoestima, o bem-estar material percebido, a discriminação pessoal percebida e a identidade nacional, emergiram como preditoras da satisfação vital. Contudo, não foi confirmada a relação negativa hipotética entre a satisfação vital e o preconceito grupal percebido. É feita uma análise desses resultados desde a literatura psicossocial.The aim of this research was to study the relationship between life satisfaction and various psychosocial variables usually linked to international migration processes. Specifically, this study explored the relationship between life satisfaction-a cognitivedimension of subjective well-being- and perceived group prejudice, perceived personal discrimination, global personal self-esteem, national identity and perceived material well- being. The research, of empirical quantitative type, was conducted with a non-probabilistic sample of Colombian migrants at several cities of Ecuador. As expected, the hypothesis that life satisfaction was positively related to self -esteem and perceived material well-being was confirmed. Also, a negative correlation was confirmed between life satisfaction, perceived personal discrimination and national identity. Results show that the variables self-esteem, perceived material well-being, perceived personal discrimination and national identity are significant predictors of life satisfaction. Findings didn´t confirm the expected negative association between life satisfaction and perceived group prejudice. Results are analyzed from a psychosocial perspective
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