4,674 research outputs found

    Naval History by Conspiracy Theory: The British Admiralty before the First World War and the Methodology of Revisionism

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    Revisionist interpretations of British naval policy in the Fisher era claim that an elaborate smoke screen was created to hide the Royal Navy’s real policies; while documents showing the true goals were systematically destroyed. By asserting this, revisionists are able to dismiss those parts of the documentary record that contradict their theories, while simultaneously excusing the lack of evidence for their theories by claiming it has been destroyed. This article shows that this methodology is misleading and untenable

    High pressure X-ray preionized TEMA-CO2 laser

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    The construction of a high-pressure (up to 20 atm) transversely excited CO2 laser using transverse X-ray preionization is described. High pressure operation was found to be greatly improved in comparison to UV-preionized systems. Homogeneous discharges have been achieved in the pressure range 5–20 atm, yielding a specific laser output in the order of 35 J/l

    Interrupted Vs. Uninterrupted Training on BMD During Growth

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    This study compared a resistance training program where the exercise was uninterrupted (UT, i.e., continuous repetitions) against a resistance training program where the exercise was interrupted (IT, i.e., 3 exercise sessions during a training day) for enhancing bone modeling and bone mineral density (BMD) in maturating animals. The total volume of work performed between the two resistance training programs was equivalent by design. 24 young male rats were randomly divided into Control (Con, n = 8), UT (n = 8) and IT (n=8) resistance trained groups. The UT and IT groups were conditioned to climb a vertical ladder with weights appended to their tail 3 days/wk for 6 wks. After the 6-wk program, serum osteocalcin was not significantly different between groups, whereas the adjusted urinary deoxypyridinoline (DPD) was significantly lower for both UT (81.03 +/- 5.53) and IT (88.30 +/- 7.29) compared to Con (128.13 +/- 9.99). Tibial BMD (assessed via DXA) was significantly greater for UT (0.222 +/- 0.005g/cm(2)) and IT (0.219 +/- 0.003g/cm(2)) when compared to Con (0.205 +/- 0.004g/cm(2)). There was no significant difference in DPD or BMD between UT and IT groups. The results indicate that both interrupted and continuous, uninterrupted resistance training programs were equally effective in stimulating bone modeling

    Survey on Visual Impairment and Refractive Errors on Ta’u Island, American Samoa

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    Purpose: To assess the prevalence of presenting visual impairment and refractive errors on the isolated island of Ta′u, American Samoa. Methods: Presenting visual acuity and refractive errors of 124 adults over 40 years of age (55 male and 69 female) were measured using the Snellen chart and an autorefractometer. This sample represented over 50% of the island′s eligible population. Results: In this survey, all presenting visual acuity (VA) was uncorrected. Of the included sample, 10.5% presented with visual impairment (visual acuity lower than 6/18, but equal to or better than 3/60 in the better eye) and 4.8% presented with VA worse than 6/60 in the better eye. Overall, 4.0% of subjects presented with hyperopia (+3 D or more), 3.2% were myopic (‑1 D or less), and 0.8% presented with high myopia (‑5 D or less). There was no significant difference between genders in terms of visual impairment or refractive errors. Conclusion: This study represents the first population-based survey on presenting visual acuity and refractive errors in American Samoa. In addition to providing baseline data on vision and refractive errors, we found that the prevalence of myopia and hyperopia was much lower than expected

    Pharmacological And Genetic Reversal Of Age-Dependent Cognitive Deficits Attributable To Decreased Presenilin Function

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    Alzheimer\u27s disease (AD) is the leading cause of cognitive loss and neurodegeneration in the developed world. Although its genetic and environmental causes are not generally known, familial forms of the disease (FAD) are attributable to mutations in a single copy of the Presenilin (PS) and amyloid precursor protein genes. The dominant inheritance pattern of FAD indicates that it may be attributable to gain or change of function mutations. Studies of FAD-linked forms of presenilin (psn) in model organisms, however, indicate that they are loss of function, leading to the possibility that a reduction in PS activity might contribute to FAD and that proper psn levels are important for maintaining normal cognition throughout life. To explore this issue further, we have tested the effect of reducing psn activity during aging in Drosophila melanogaster males. We have found that flies in which the dosage of psn function is reduced by 50% display age-onset impairments in learning and memory. Treatment with metabotropic glutamate receptor (mGluR) antagonists or lithium during the aging process prevented the onset of these deficits, and treatment of aged flies reversed the age-dependent deficits. Genetic reduction of Drosophila metabotropic glutamate receptor (DmGluRA), the inositol trisphosphate receptor (InsP(3)R), or inositol polyphosphate 1-phosphatase also prevented these age-onset cognitive deficits. These findings suggest that reduced psn activity may contribute to the age-onset cognitive loss observed with FAD. They also indicate that enhanced mGluR signaling and calcium release regulated by InsP(3)R as underlying causes of the age-dependent cognitive phenotypes observed when psn activity is reduced

    Resistance Training and Bone Mineral Density During Growth

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    This study examined the efficacy of two different resistance training programs in enhancing bone modeling and bone mineral density (BMD) in maturating rats. One exercise mode involved lifting a lighter weight with more repetitions (LI), while the other regimen involved lifting a heavier weight with fewer repetitions (HI) where the total volume of work between exercise programs was equivalent by design. Twenty-three male rats were randomly divided into control (Con, n = 8), LI (n = 7), and HI (n = 8) groups. The LI and HI groups were conditioned to climb a vertical ladder with weights appended to their tail 4 days/wk for 6 wks. After training, serum osteocalcin (OC) was significantly (p \u3c 0.05) higher in both HI (45.2 +/- 1.7 ng/ml) and Ll (39.1 +/- 2.2 ng/ml) when compared to Con (29.9 +/- 0.9 ng/ml). Left tibial BMD was significantly (p \u3c 0.05) greater for HI (0.231 +/- 0.004 g/cm(2)) when compared to both LI (0.213 +/- 0.003 g/cm(2)) and Con (0.206 +/- 0.005 g/cm(2)) with no significant difference between Ll and Con. The results indicate that both HI and LI are effective in elevating serum OC, implicating an osteogenic response; however, only HI resulted in a significant elevation in BMD

    Equal BMD After Daily Or Triweekly Exercise In Growing Rats

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    The purpose of this study was to examine the efficacy of continuous resistance training (3 days/wk) compared to interrupted resistance training where 20-24 h separated an exercise bout (i.e. 6 days/wk) for enhancing bone mineral density (BMD) in growing male rats. The total volume of work performed per week between the two resistance training programs was equivalent by design. Young male rats were randomly divided into Control (Con, n = 9), 3 days/wk resistance trained group (RT3, n = 9), and 6 days/wk resistance trained group (RT6, n = 9). The RT3 and RT6 groups were conditioned to climb a vertical ladder with weights appended to their tail for a total of 6 wks. After 6 wks, BMD (assessed via DXA) from the left tibia was significantly greater for RT3 (0.242 +/- 0.004 g/cm(2)) and RT6 (0.244 +/- 0.004 g/cm(2)) compared to Con (0.226 +/- 0.003 g/cm(2) ). Further, serum osteocalcin (oc, in ng/ml) was significantly greater for RT3 (75.8 +/- 4.4) and RT6 (73.5 +/- 3.8) compared to Con (53.4 +/- 2.4). There was no significant difference in BMD or serum OC between RT3 and RT6 groups. The results indicate that both resistance training programs were equally effective in elevating bone mineral density in young, growing rats

    Search for the decay KL0→3γK_L^0 \rightarrow 3\gamma

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    We performed a search for the decay KL0→3γK_L^0 \rightarrow 3\gamma with the E391a detector at KEK. In the data accumulated in 2005, no event was observed in the signal region. Based on the assumption of KL0→3γK_L^0 \rightarrow 3\gamma proceeding via parity-violation, we obtained the single event sensitivity to be (3.23±0.14)×10−8(3.23\pm0.14)\times10^{-8}, and set an upper limit on the branching ratio to be 7.4×10−87.4\times10^{-8} at the 90% confidence level. This is a factor of 3.2 improvement compared to the previous results. The results of KL0→3γK_L^0 \rightarrow 3\gamma proceeding via parity-conservation were also presented in this paper
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