1,523 research outputs found

    Polar cap observations of thermospheric winds and temperatures at Sondre Stromfjord, Greenland

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    An agreement of averaged temperatures with mass spectrometer incoherent scatter radar looked reasonable for several nights, but for many nights there are differences: (1) midnight period of cooling, and (2) temperature increases associated with overhead crossings of the auroral belt. The observed rise of the temperature before dawn in conjunction with the high 6300A intensities suggests a connection between the two effects: soft particle precipitation most likely candidate but frictional heating perhaps also a possibility. A comparison with the thermospheric general circulation model calculations also needed. The technique for formulating neutral wind vectors performs well in most cases. The observed patterns show evidence for abatement in the midnight sector in the meridional wind component at the separatix between the two cells with a frequency of the order of 20 to 25%, also observed in radar observations at Sondre Stromfjord. The observed patterns for magnetically quiet conditions show flow characteristic of the auroral belt, westward in evening followed by the midnight surge. The observed patterns for active conditions show dominance either by the evening cell or the morning cell, but most often the former

    Ground-based observations of equatorial thermosphere dynamics with a Fabry-Perot interferometer

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    Fabry-Perot determinations of thermospheric temperatures from 630.0 nm nightglow line width measurements were carried out for the period April to August, 1983. The nightly variation of the thermospheric temperature measured on 53 nights is compared with MSIS model predictions and found to agree occasionally with the model but, on the average, to exceed model predictions by approximately 180 K. The largest differences, 400 to 500 K occur during strongly increasing geomagnetic activity. Significant differences occur both during high geomagnetic/low solar activity and during low geomagnetic/high solar activity

    Evidence Rule 806 and the Problem of Impeaching the Nontestifying Declarant

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    Does tamoxifen prevent breast cancer?

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    Tamoxifen prevents breast cancer in women older than 60 years and in younger women with equally high risk because of breast disease and reproductive and family history, but there is no current evidence for or against long-term survival or overall health benefits.(Grade of recommendation A: randomized controlled trials [RCTs]) a 49% reduction in 5-year incidence of invasive and noninvasive breast cancer but increased risk for endometrial cancer, pulmonary emboli, deep vein thrombosis, and cataracts. The long-term benefits and overall health effects of tamoxifen for primary prevention of breast cancer remain unclear; the ongoing International Breast Cancer Intervention Study trial is designed to address this question

    Neutral winds above 200Km at high latitudes

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    Motion from multiple chemical releases between 200 and 300 km from 15 rockets launched from 4 high latitude locations are analyzed. The observations in the evening and midnight hours at magnetic altitudes or = 65 deg suggest that in these regions ion drag is the dominant force in driving neutral winds between 200 and 300 km. This conclusion is based on both the agreement between ion and neutral drift directions, and the fact that there are distinct changes in the wind associated with (a) the reversal in east-west ion drift at the Harang discontinuity, and (b) the transition from auroral belt, sunward ion drift and polar cap, anti-solar ion drift

    The mesospheric inversion layer and sprites

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    The vertical structure of temperature observed by SABER (Sounding of Atmosphere using Broadband Emission Radiometry) aboard TIMED (Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics) and sprites observations made during the Eurosprite 2003 to 2007 observational campaign were analyzed. Sprite observations were made at two locations in France, namely Puy de Dome in the French Massif Central and at the Pic du Midi in the French Pyrenees. It is observed that the vertical structure of temperature shows evidence for a Mesospheric Inversion Layer (MIL) on those days on which sprites were observed. A few events are also reported in which sprites were not recorded, although there is evidence of a MIL in the vertical structure of the temperature. It is proposed that breaking gravity waves produced by convective thunderstorms facilitate the production of (a) sprites by modulating the neutral air-density and (b) MILs via the deposition of energy. The same proposition has been used to explain observations of lightings as well as both MILs and lightning arising out of deep convections.Comment: 34 pages, 5figures. Accepted in Journal of Geophysical Research, US

    Cancer research in need of a scientific revolution: Using 'paradigm shift' as a method of investigation.

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    International audienceDespite important human and financial resources and considerable accumulation of scientific publications, patents, and clinical trials, cancer research has been slow in achieving a therapeutic revolution similar to the one that occurred in the last century for infectious diseases. It has been proposed that science proceeds not only by accumulating data but also through paradigm shifts. Here, we propose to use the concept of 'paradigm shift' as a method of investigation when dominant paradigms fail to achieve their promises. The first step in using the 'paradigm shift' method in cancer research requires identifying its founding paradigms. In this review, two of these founding paradigms will be discussed: (i) the reification of cancer as a tumour mass and (ii) the translation of the concepts issued from infectious disease in cancer research. We show how these founding paradigms can generate biases that lead to over-diagnosis and over-treatment and also hamper the development of curative cancer therapies. We apply the 'paradigm shift' method to produce perspective reversals consistent with current experimental evidence. The 'paradigm shift' method enlightens the existence of a tumour physiologic-prophylactic-pathologic continuum. It integrates the target/antitarget concept and that cancer is also an extracellular disease. The 'paradigm shift' method has immediate implications for cancer prevention and therapy. It could be a general method of investigation for other diseases awaiting therap

    Robert L. Meriwether and the South Caroliniana Library

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    Though praised as an outstanding scholar, Robert L. Meriwether was perhaps most proud of his work in helping other scholars as a teacher, editor, archivist, and librarian, with the founding of the South Caroliniana Library as the pinnacle of those efforts. Born in Edgefield County, South Carolina, in 1890, his love of history and affection for his native state seem inextricably intertwined from a young age. This might be expected from someone raised in the wake of Reconstruction in a state that had endured so much loss and upheaval in the Civil War and its aftermath. Indeed, in many ways, his early life illustrates how South Carolinians attempted to recover from the aftershocks of those events
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