7,788 research outputs found

    Effects of an 8-year childhood physical activity intervention on musculoskeletal gains and fracture risk

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    Background Physical activity (PA) in childhood is associated with musculoskeletal benefits while the effect on fracture risk is yet to be determined. The aim of this study was to evaluate whether extension of a PA intervention leads to improvement in musculoskeletal traits with an accompanied reduced fracture risk. We hypothesized that the PA program would have beneficial effects in both sexes, but more so in girls since they tend to be less physically active than boys during this time frame. Methods In one elementary school we increased physical education (PE) from 60 to 200 min per school week and followed 65 girls and 93 boys from a mean age of 7 years until a mean age of 15 years. Thirty-nine girls and 37 boys in three other schools continued with 60 min of PE per week during the same years and served as controls. We measured bone mineral content (BMC), areal bone mineral density (aBMD), and bone area annually with dual energy X-ray absorptiometry, and leg muscle strength with a computerized dynamometer. In 3534 children within the same PE program (1339 in the intervention and 2195 in the control group) we registered incident fractures during the 8-year study period and estimated annual sex-specific fracture incidence rate ratios (IRRs). Results Girls in the intervention group annually gained more total body less head aBMD, spine aBMD (p < 0.01), femoral neck BMC (p < 0.05), lumbar vertebrae size (p < 0.05), and knee flexion strength (p < 0.05) than girls in the control cohort. In boys we found no group differences. There was an inverse correlation between number of years with extra PE and the annual IRR of sustaining fractures in both girls (r = − 0.90 (95% CI − 0.98 to − 0.51); p < 0.001) and boys (r = − 0.74 (95% CI − 0.94 to − 0.02); p < 0.05). Conclusion In this 8-year pediatric school-based moderate exercise intervention program there is an inverse correlation in both sexes between annual IRR and each additional year of extra PA. A sub-cohort of girls in the intervention group had greater gains in bone mass, bone size, and muscle strength, which could possibly explain the inverse correlation between years within the PA program and fracture risk, while in boys the reason for the inverse correlation remains unknown. It should be noted that differences in unreported factors such as skeletal maturity status, diet, and spare time PA could confound our inferences. That is, true causality cannot be stated

    Distances of Quasars and Quasar-Like Galaxies: Further Evidence that QSOs may be Ejected from Active Galaxies

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    If high-redshift QSOs are ejected from the nuclei of low-redshift galaxies, as some have claimed, a large portion of their redshift must be intrinsic (non-Doppler). If these intrinsic components have preferred values, redshifts will tend to cluster around these preferred values and produce peaks in the redshift distribution. Doppler ejection and Hubble flow components will broaden each peak. Because ejection velocities are randomly directed and Hubble flow components are always positive, in this model all peaks are expected to show an asymmetry, extending further out in the red wing. If peaks are present showing this predicted asymmetry, it can lead directly to an estimate of quasar distances. Using two quasar samples, one with high redshifts and one with low, it is shown here that not only do all peaks in these two redshift distributions occur at previously predicted preferred values, they also all show the predicted extra extension in the red wing. For the low and high redshift samples the mean cosmological components are found to be zc∌0.024_{c} \sim 0.024 and ∌0.066\sim 0.066, respectively. The difference can be explained by the improved detection limit of the high redshift sample. These results offer further evidence in favor of the model proposing that QSOs are ejected from active galaxies.Comment: 11 pages, 6 figures, accepted for publication in The Astrophysical Journa

    Carbon and oxygen isotope composition of carbonates from an L6 chondrite: Evidence for terrestrial weathering from the Holbrook meteorite

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    Terrestrial weathering in meteorites is an important process which alters pristine elemental and isotopic abundances. The Holbrook L6 chondrite fell in 1912. Material was recovered at the time of the fall, in 1931, and 1968. The weathering processes operating on the freshly fallen meteorite in a semi-arid region of northeastern Arizona have been studied after a ground residence of 19 and 56 years. It has been shown that a large portion of the carbonate material in 7 Antarctic ordinary chondrites either underwent extensive isotopic exchange with atmospheric CO2, or formed recently in the Antarctic environment. In fact it has been demonstrated that hydrated Mg-carbonates, nesquehonite and hydromagnesite, formed in less than 40 years on LEW 85320. In order to help further constrain the effects of terrestrial weathering in meteorites, the carbon and oxygen isotopes extracted from carbonates of three different samples of Holbrook L6: a fresh sample at the time of the fall in 1912, a specimen collected in 1931, and a third specimen collected at the same site in 1968

    Sodium content in processed food items in Sweden compared to other countries: a cross-sectional multinational study

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    Background: Dietary sodium has a dose-response relationship with cardiovascular disease, and sodium intake in Sweden exceeds national and international recommendations. Two thirds of dietary sodium intake comes from processed foods, and adults in Sweden eat more processed foods than any other European country. We hypothesized that sodium content in processed foods is higher in Sweden than in other countries. The aim of this study was to investigate sodium content in processed food items in Sweden, and how it differs from Australia, France, Hong Kong, South Africa, the United Kingdom and the United States. Methods: Data were collected from retailers by trained research staff using standardized methods. Data were categorized into 10 food categories and compared using Kruskal-Wallis test of ranks. Sodium content in the food items was compared in mg sodium per 100 g of product, based on the nutritional content labels on the packages. Results: Compared to other countries, Sweden had among the highest sodium content in the “dairy” and “convenience foods” categories, but among the lowest in “cereal and grain products,” “seafood and seafood products” and “snack foods” categories. Australia had the overall lowest sodium content, and the US the overall highest. The highest sodium content in most analyzed countries was found in the “meat and meat products” category. The highest median sodium content in any category was found among “sauces, dips, spreads and dressings” in Hong Kong. Conclusion: The sodium content differed substantially between countries in all food categories, although contrary to our hypothesis, processed foods overall had lower sodium content in Sweden than in most other included countries. Sodium content in processed food was nonetheless high also in Sweden, and especially so in increasingly consumed food categories, such as “convenience foods”

    The relationship between biophysical variables and halocarbon distributions in the waters of the Amundsen and Ross Seas, Antarctica

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    Little is known regarding the distribution of volatile halogenated organic compounds (halocarbons) in Antarctic waters and their relation to biophysical variables. During the austral summer (December to January) in 2007-08 halocarbon and pigment concentrations were measured in the Amundsen (100-130 degrees W) and Ross Sea (158 degrees W-160 degrees E). In addition, halocarbons were determined in air, snow and sea ice. The distribution of halocarbons was influenced to a large extent by sea ice, and to a much lesser extent by pelagic biota. Concentrations of naturally produced halocarbons were elevated in the surface mixed layer in ice covered areas compared to open waters in polynyas and in the bottom waters of the Ross Sea. Higher concentrations of halocarbons were also found in sea ice brine compared to the surface waters. Incubations of snow revealed an additional source of halocarbons. The distribution of halocarbons also varied considerably between the Amundsen and Ross Seas, mainly due to the different oceanographic settings. For iodinated compounds, weak correlations were found with the presence of pigments indicative of Phaeocystis, mainly in the Ross Sea. Surface waters of the Amundsen and Ross Seas are a sink for bromoform (saturation anomalies, SA, -83 to 11%), whereas sea ice was found to be both a source and sink (SA -61-97%). In contrast, both surface waters and sea ice were found to be a source of chloroiodomethane (SA -6-1 200% and 91-22 000 resp.). Consequently, polar waters can have a substantial impact on global halocarbon budgets and need to be included in large-scale assessments. (C) 2012 Elsevier B.V. All rights reserved

    The Distribution of Redshifts in New Samples of Quasi-stellar Objects

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    Two new samples of QSOs have been constructed from recent surveys to test the hypothesis that the redshift distribution of bright QSOs is periodic in log⁥(1+z)\log(1+z). The first of these comprises 57 different redshifts among all known close pairs or multiple QSOs, with image separations ≀\leq 10\arcsec, and the second consists of 39 QSOs selected through their X-ray emission and their proximity to bright comparatively nearby active galaxies. The redshift distributions of the samples are found to exhibit distinct peaks with a periodic separation of ∌0.089\sim 0.089 in log⁥(1+z)\log(1+z) identical to that claimed in earlier samples but now extended out to higher redshift peaks z=2.63,3.45z = 2.63, 3.45 and 4.47, predicted by the formula but never seen before. The periodicity is also seen in a third sample, the 78 QSOs of the 3C and 3CR catalogues. It is present in these three datasets at an overall significance level 10−510^{-5} - 10−610^{-6}, and appears not to be explicable by spectroscopic or similar selection effects. Possible interpretations are briefly discussed.Comment: submitted for publication in the Astronomical Journal, 15 figure

    Contribution of sea ice in the Southern Ocean to the cycling of volatile halogenated organic compounds

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    The contribution of sea ice to the flux of biogenic volatile halogenated organic compounds to the atmosphere in the Southern Ocean is currently not known. To approach this question, we measured halocarbons in sea ice, sea ice brine, and surface water of the Amundsen and Ross Seas. Concentrations in sea ice of these compounds, normalized to seawater salinity, ranged from 0.2 to 810 pmol L-1. Salinity-normalized chlorophyll a concentrations in the ice ranged from 3.5 to 190 mu gL(-1). Our results suggest biological production of halocarbons in sea ice, with maxima of halogenated organics and chlorophyll a commonly found in the interior of the ice cores. Iodinated VHOCs were found to be more enriched in sea ice than brominated ones. Furthermore, depth distributions indicated a transport of halocarbons from sea ice to air and underlying water

    Prediction of Outcome After Endovascular Embolectomy in Anterior Circulation Stroke Using Biomarkers

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    Stroke is a major public health problem that can cause a long-term disability or death due to brain damage. Serious stroke is frequently caused by a large vessel occlusion in the anterior circulation, which should be treated by endovascular embolectomy if possible. In this study, we investigated the use of the brain damage biomarkers tau, NFL, NSE, GFAp, and S100B to understand the progression of nervous tissue damage and their relationship to outcome in such stroke after endovascular treatment. Blood samples were taken from 90 patients pre-treatment and 2 h, 24 h, 48 h, 72 h and 3 months after endovascular treatment. Stroke-related neurological deficit was estimated using the National Institute of Health Stroke Scale (NIHSS) at admission and at 24 h. Neurological outcome was evaluated at 3 months. After stroke, tau, NFL, GFAp and S100B increased in a time dependent manner, while NSE remained constant over time. At 3 months, tau and GFAp levels were back to normal whereas NFL was still high. Tau, NFL and GFAp correlated well to outcome, as well as to infarct volume and NIHSS at 24 h. The best time for prediction of poor outcome was different for each biomarker. However, the combination of NIHSS at 24 h with either tau, NFL or GFAp at 48 h gave the best prediction. The use of biomarkers in the early setting after endovascular treatment of stroke will lead to a simplified and standardized way to estimate the nervous tissue damage and possibly complement the clinical judgement in foreseeing the need of rehabilitation measures

    Short-Term Antibiotic Treatment Has Differing Long-Term Impacts on the Human Throat and Gut Microbiome

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    Antibiotic administration is the standard treatment for the bacterium Helicobacter pylori, the main causative agent of peptic ulcer disease and gastric cancer. However, the long-term consequences of this treatment on the human indigenous microbiota are relatively unexplored. Here we studied short- and long-term effects of clarithromycin and metronidazole treatment, a commonly used therapy regimen against H. pylori, on the indigenous microbiota in the throat and in the lower intestine. The bacterial compositions in samples collected over a four-year period were monitored by analyzing the 16S rRNA gene using 454-based pyrosequencing and terminal-restriction fragment length polymorphism (T-RFLP). While the microbial communities of untreated control subjects were relatively stable over time, dramatic shifts were observed one week after antibiotic treatment with reduced bacterial diversity in all treated subjects in both locations. While the microbiota of the different subjects responded uniquely to the antibiotic treatment some general trends could be observed; such as a dramatic decline in Actinobacteria in both throat and feces immediately after treatment. Although the diversity of the microbiota subsequently recovered to resemble the pre treatment states, the microbiota remained perturbed in some cases for up to four years post treatment. In addition, four years after treatment high levels of the macrolide resistance gene erm(B) were found, indicating that antibiotic resistance, once selected for, can persist for longer periods of time than previously recognized. This highlights the importance of a restrictive antibiotic usage in order to prevent subsequent treatment failure and potential spread of antibiotic resistance

    "Assisted cloning'' and "orthogonal-complementing" of an unknown state

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    We propose a protocol where one can exploit dual quantum and classical channels to achieve perfect ``cloning'' and ``orthogonal-complementing'' of an unknown state with a minimal assistance from a state preparer (without revealing what the input state is). The first stage of the protocol requires usual teleportation and in the second stage, the preparer disentangles the left-over entangled states by a single particle measurement process and communicates a number of classical bits (1-cbit per copy) to different parties so that perfect copies and complement copies are produced. We discuss our protocol for producing two copies and three copies (and complement copies) using two and four particle entangled state and suggest how to generalise this for N copies and complement copies using multiparticle entangled state.Comment: 7 pages, Latex, no figures, submitted to Phys. Rev. A. 1999(to be accepted
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