2,049 research outputs found

    Keys to Profitable Guar Production.

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    Are the average gait speeds during the 10 meter and 6 minute walk tests redundant in Parkinson disease?

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    Published in final edited form as: Gait Posture. 2017 February ; 52: 178–182. doi:10.1016/j.gaitpost.2016.11.033.We investigated the relationships between average gait speed collected with the 10Meter Walk Test (Comfortable and Fast) and 6Minute Walk Test (6MWT) in 346 people with Parkinson disease (PD) and how the relationships change with increasing disease severity. Pearson correlation and linear regression analyses determined relationships between 10Meter Walk Test and 6MWT gait speed values for the entire sample and for sub-samples stratified by Hoehn & Yahr (H&Y) stage I (n=53), II (n=141), III (n=135) and IV (n=17). We hypothesized that redundant tests would be highly and significantly correlated (i.e. r>0.70, p<0.05) and would have a linear regression model slope of 1 and intercept of 0. For the entire sample, 6MWT gait speed was significantly (p<0.001) related to the Comfortable 10 Meter Walk Test (r=0.75) and Fast 10Meter Walk Test (r=0.79) gait speed, with 56% and 62% of the variance in 6MWT gait speed explained, respectively. The regression model of 6MWT gait speed predicted by Comfortable 10 Meter Walk gait speed produced slope and intercept values near 1 and 0, respectively, especially for participants in H&Y stages II-IV. In contrast, slope and intercept values were further from 1 and 0, respectively, for the Fast 10Meter Walk Test. Comfortable 10 Meter Walk Test and 6MWT gait speeds appeared to be redundant in people with moderate to severe PD, suggesting the Comfortable 10 Meter Walk Test can be used to estimate 6MWT distance in this population.This study was funded by the Davis Phinney Foundation, the Parkinson's Disease Foundation, and the National Institutes of Health (R01 NS077959, K12 HD055931, UL1 TR000448). The funding sources had no input related to study design, data collection, or decision to submit for publication. (Davis Phinney Foundation; Parkinson's Disease Foundation; R01 NS077959 - National Institutes of Health; K12 HD055931 - National Institutes of Health; UL1 TR000448 - National Institutes of Health

    A Procedure for Determining the Relative Volume of Mitochondria in Hepatic Cells

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    About forty years ago Cowdry\u27s monograph on mitochondria appeared evaluating the work of previous investigators, indicating synonymy and, in a sense, bringing the first exploratory phase of the study of these cellular constituents to a close (1). Reasonably specific methods for their demonstration had been devised, and it was possible to have some confidence in the conclusions that the so-called mitochondria of different kinds of cells, despite dissimilarities in size or shape, were comparable cellular parts

    Short-range cluster spin glass near optimal superconductivity in BaFe2−x_{2-x}Nix_{x}As2_{2}

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    High-temperature superconductivity in iron pnictides occurs when electrons are doped into their antiferromagnetic (AF) parent compounds. In addition to inducing superconductivity, electron-doping also changes the static commensurate AF order in the undoped parent compounds into short-range incommensurate AF order near optimal superconductivity. Here we use neutron scattering to demonstrate that the incommensurate AF order in BaFe2−x_{2-x}Nix_{x}As2_{2} is not a spin-density-wave arising from the itinerant electrons in nested Fermi surfaces, but consistent with a cluster spin glass in the matrix of the superconducting phase. Therefore, optimal superconductivity in iron pnictides coexists and competes with a mesoscopically separated cluster spin glass phase, much different from the homogeneous coexisting AF and superconducting phases in the underdoped regime.Comment: 4 figure

    O ‘Darwinismo Social’ Perante a Questão da Assistência

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    Tendo como referência o quadro de miséria/ pauperismo do século XIX, o propósito crítico deste ensaio é a influência da teoria darwinista na questão social. Após um breve enquadramento dessas reflexões, no quadro da problemática da pobreza, a ênfase é colocada no pensamento de Herbert Spencer que advogava os aspectos positivos da pobreza enquanto instrumento de selecção dos menos capazes. O que está em causa, para o autor deste artigo, é demonstrar como esses mesmos argumentos spencerianos emergiram em defesa de um posicionamento crítico no quadro de qualquer tipo de intervenção assistencial. / In the context of the 19th century framework of misery/pauperism, the critical purpose of this article is the influence of the Darwinian theory on the social question. After a brief framing of those reflections, the emphasis is placed on the thought of Herbert Spencer about what he considered the positive aspects of poverty as a selection instrument of the less capable. What is at question, for the author of this article, is to demonstrate how the Spencerian thought on poverty defend, in fact, a critical position in the field of any kind of assistance intervention

    Heuristic Segmentation of a Nonstationary Time Series

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    Many phenomena, both natural and human-influenced, give rise to signals whose statistical properties change under time translation, i.e., are nonstationary. For some practical purposes, a nonstationary time series can be seen as a concatenation of stationary segments. Using a segmentation algorithm, it has been reported that for heart beat data and Internet traffic fluctuations--the distribution of durations of these stationary segments decays with a power law tail. A potential technical difficulty that has not been thoroughly investigated is that a nonstationary time series with a (scale-free) power law distribution of stationary segments is harder to segment than other nonstationary time series because of the wider range of possible segment sizes. Here, we investigate the validity of a heuristic segmentation algorithm recently proposed by Bernaola-Galvan et al. by systematically analyzing surrogate time series with different statistical properties. We find that if a given nonstationary time series has stationary periods whose size is distributed as a power law, the algorithm can split the time series into a set of stationary segments with the correct statistical properties. We also find that the estimated power law exponent of the distribution of stationary-segment sizes is affected by (i) the minimum segment size, and (ii) the ratio of the standard deviation of the mean values of the segments, and the standard deviation of the fluctuations within a segment. Furthermore, we determine that the performance of the algorithm is generally not affected by uncorrelated noise spikes or by weak long-range temporal correlations of the fluctuations within segments.Comment: 23 pages, 14 figure

    Some Aspects of Quantitative Histology of the Liver of A-Jax Mice Before and During Tumor Induction with Carbon Tetrachloride

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    The proportion of the cell populations composed of parenchymal, littoral, and other types of cells is reported for control mice, mice repeatedly anesthetized, mice fed with olive oil repeatedly, and mice fed with carbon tetrachloride and olive oil, showing that the cellular components undergo a marked change when carbon tetrachloride is administered. The proportion of the liver volume occupied by parenchymal cells is found to be relatively stable throughout the period of tumor induction. The nuclear-cytoplasmic ratio of parenchymal cells is found to fall with the aging of control mice and those fed olive oil or anesthetized during the period of the experiment. The nuclear-cytoplasmic ratio is found to fall to a minimal point during the first two weeks of carbon tetrachloride feeding, thereafter gradually rising to normal values for mice of the same age, and eventually rising, after 24 feedings, to a value exceeding that of normal mice of the same age. Between 24 and 30 feedings the nuclear-cytoplasmic ratio undergoes a decrease. The volumes of parenchymal cell nuclei are found to vary with the position in a lobule, the maximal nuclear volumes being found in a region about 100μ to 200μ from the central vein in lobules of average size

    Delays in IP routers, a Markov model

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    Delays in routers are an important component of end-to-end delay and therefore have a significant impact on quality of service. While the other component, the propagation time, is easy to predict as the distance divided by the speed of light inside the link, the queueing delays of packets inside routers depend on the current, usually dynamically changing congestion and on the stochastic features of the flows. We use a Markov model taking into account the distribution of the size of packets and self-similarity of incoming flows to investigate their impact on the queueing delays and their dynamics

    Measuring portfolio performance using a modified measure of risk

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    This paper reports the results of an investigation into the properties of a theoretical modification of beta proposed by Leland (1999) and based on earlier work of Rubinstein (1976). It is shown that when returns are elliptically symmetric, beta is the appropriate measure of risk and that there are other situations in which the modified beta will be similar to the traditional measure based on the capital asset pricing model. For the case where returns have a normal distribution, it is shown that the criterion either does not exist or reduces exactly to the conventional beta. It is therefore conjectured that the modified measure will only be useful for portfolios that have nonstandard return distributions which incorporate skewness. For such situations, it is shown how to estimate the measure using regression and how to compare the resulting statistic with a traditional estimated beta using Hotelling's test. An empirical study based on stocks from the FTSE350 does not find evidence to support the use of the new measure even in the presence of skewness.Journal of Asset Management (2007) 7, 388-403. doi:10.1057/palgrave.jam.225005

    How U.S. Ocean Policy and Market Power Can Reform the Coral Reef Wildlife Trade

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    As the world’s largest importer of marine ornamental species for the aquaria, curio, home décor, and jewelry industries, the United States has an opportunity to leverage its considerable market power to promote more sustainable trade and reduce the effects of ornamental trade stress on coral reefs worldwide. Evidence indicates that collection of some coral reef animals for these trades has caused virtual elimination of local populations, major changes in age structure, and promotion of collection practices that destroy reef habitats. Management and enforcement of collection activities in major source countries such as Indonesia and the Philippines remain weak. Strengthening US trade laws and enforcement capabilities combined with increasing consumer and industry demand for responsible conservation can create strong incentives for improving management in source countries. This is particularly important in light of the March 2010 failure of the parties to the Convention on International Trade in Endangered Species (CITES) to take action on key groups of corals
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