674 research outputs found

    Application of satellite imagery to hydrologic modeling snowmelt runoff in the southern Sierra Nevada

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    There are no author-identified significant results in this report

    Oral contraception and eye disease: findings in two large cohort studies

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    AIM : To investigate the relation between oral contraceptive use and certain eye diseases. \ud \ud METHODS : Abstraction of the relevant data from the two large British cohort studies of the effects of oral contraception, the Royal College of General Practitioners' (RCGP) Oral Contraception Study and the Oxford-Family Planning Association (Oxford-FPA) Contraceptive Study. Both cohort studies commenced in 1968 and were organised on a national basis. Between them they have accumulated over 850 000 person years of observation involving 63 000 women. \ud \ud RESULTS : The conditions considered in the analysis were conjunctivitis, keratitis, iritis, lacrimal disease, strabismus, cataract, glaucoma, retinal detachment, and retinal vascular lesions. With the exception of retinal vascular lesions, there was no consistent evidence of important increases in risk of eye diseases in users of oral contraception. There was about a twofold increase in the risk of retinal vascular lesions in recent pill users in both studies (statistically significant only in the RCGP study). The increase was not limited to any specific type of lesion and may well reflect diagnostic bias. \ud \ud CONCLUSION : Oral contraceptive use does not appear to increase the risk of eye disease, with the possible exception of retinal vascular lesions. \ud \ud Keywords: oral contraception; eye disease; cohort studie

    Condensate splitting in an asymmetric double well for atom chip based sensors

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    We report on the adiabatic splitting of a BEC of 87^{87}Rb atoms by an asymmetric double-well potential located above the edge of a perpendicularly magnetized TbGdFeCo film atom chip. By controlling the barrier height and double-well asymmetry the sensitivity of the axial splitting process is investigated through observation of the fractional atom distribution between the left and right wells. This process constitutes a novel sensor for which we infer a single shot sensitivity to gravity fields of δg/g2×104\delta g/g\approx2\times10^{-4}. From a simple analytic model we propose improvements to chip-based gravity detectors using this demonstrated methodology.Comment: 4 pages, 5 figure

    The use of snowcovered area in runoff forecasts

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    Long-term snowcovered area data from aircraft and satellite observations have proven useful in reducing seasonal runoff forecast error on the Kern river watershed. Similar use of snowcovered area on the Kings river watershed produced results that were about equivalent to methods based solely on conventional data. Snowcovered area will be most effective in reducing forecast procedural error on watersheds with: (1) a substantial amount of area within a limited elevation range; (2) an erratic precipitation and/or snowpack accumulation pattern not strongly related to elevation; and (3) poor coverage by precipitation stations or snow courses restricting adequate indexing of water supply conditions. When satellite data acquisition and delivery problems are resolved, the derived snowcover information should provide a means for enhancing operational streamflow forecasts for areas that depend primarily on snowmelt for their water supply

    Inversion produces opposite size illusions for faces and bodies

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    Faces are complex, multidimensional, and meaningful visual stimuli. Recently, Araragi and colleagues (Araragi, Aotani, & Kitaoka, 2012) demonstrated an intriguing face size illusion whereby an inverted face is perceived as larger than a physically identical upright face. Like the face, the human body is a highly familiar and important stimulus in our lives. Here, we investigated the specificity of the size underestimation of upright faces illusion, testing whether similar effects also hold for bodies, hands, and everyday objects. Experiments 1a and 1b replicated the face-size illusion. No size illusion was observed for hands or objects. Unexpectedly, a reverse size illusion was observed for bodies, so that upright bodies were perceived as larger than their inverted counterparts. Experiment 2 showed that the face and reverse body size illusions were maintained even when the photographic contrast polarity of the stimuli was reversed, indicating that the visual system driving the illusions relies on geometric featural information rather than image contrast. Our findings show that size illusions caused by inversion show a high level of category specificity, with opposite illusions for faces and bodies

    VIDEO ANALYSIS AND TREATMENT OF OVERUSE KNEE INJURY IN CYCLING: A LIMITED CLINICAL STUDY

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    Though cycling is not considered an "impact" sport, forces of three times body weight are applied to the pedals during intermittent bursts of effort such as during take off and hill climbing (13, 25). Forces equal to body weight occur during steady cycling (3, 10, 20, 25). It is known that good cyclists "spin" at an optimum pedalling frequency of from 80 to 100 revolutions per minute (5, 20, 22). This causes an exceptionally rapid flexion-extension at the knee when compared to running sports. For example, a 4:00 minute per mile pace in running causes an angular velocity at the knee that equates to no more than a 40 rpm spin rate (16)
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