544 research outputs found

    Colonization of breastfed infants by Bifidobacterium longum subsp. infantis EVC001 reduces virulence gene abundance

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    The infant gut microbiome is rapidly colonized by bacteria from the environment after birth, and this gut ecosystem can facilitate expansion of potential pathogens. Human milk shapes the infant gut microbiome and has evolved to foster the growth of specific bacteria. Breastfed infants fed the coevolved infant gut symbiont Bifidobacterium longum subsp. infantis EVC001 had significant modifications to their gut metagenome, including a decreased number of virulence factor genes

    Current distribution in a parallel configuration superconducting strip-line detector

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    Superconducting detectors based on parallel microscopic strip-lines are promising candidates for single molecule detection in time-of-flight mass spectrometry. The device physics of this configuration is complex. In this letter, we employ nano-optical techniques to study the variation of current density, count rate, and pulse amplitude transversely across the parallel strip device. Using the phenomenological London theory, we are able to correlate our results to a non-uniform current distribution between the strips, governed by the London magnetic penetration depth. This fresh perspective convincingly explains anomalous behaviour in large area parallel superconducting strip-line detectors reported in previous studies

    Reproducibility of NIRS Assessment of Muscle Oxidative Capacity in Smokers With and Without COPD

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    Low muscle oxidative capacity contributes to exercise intolerance in chronic obstructive pulmonary disease (COPD). Near-infrared spectroscopy (NIRS) allows non-invasive determination of the muscle oxygen consumption (mV̇O2) recovery rate constant (k), which is proportional to oxidative capacity assuming two conditions are met: 1) exercise intensity is sufficient to fully-activate mitochondrial oxidative enzymes; 2) sufficient O2 availability. We aimed to determine reproducibility (coefficient of variation, CV; intraclass correlation coefficient, ICC) of NIRS k assessment in the gastrocnemius of 64 participants with (FEV1 64 ± 23%predicted) or without COPD (FEV1 98 ± 14%predicted). 10–15 s dynamic contractions preceded 6 min of intermittent arterial occlusions (5–10 s each, ∼250 mmHg) for k measurement. k was lower (P < 0.05) in COPD (1.43 ± 0.4 min−1; CV = 9.8 ± 5.9%, ICC = 0.88) than controls (1.74 ± 0.69 min−1; CV = 9.9 ± 8.4%; ICC = 0.93). Poor k reproducibility was more common when post-contraction mV̇O2 and deoxygenation were low, suggesting insufficient exercise intensity for mitochondrial activation and/or the NIRS signal contained little light reflected from active muscle. The NIRS assessment was well tolerated and reproducible for muscle dysfunction evaluation in COPD

    Participation in contract farming and farm performance: Insights from cashew farmers in Ghana

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    The global demand for cashew nuts continues to increase steadily. However, many African countries face difficulties in marketing and adding value to the product. Using recent survey data of 391 cashew farmers in Ghana, this paper contributes to the grow- ing evidence on the significance of contract farming (CF) in improving the welfare of rural households in developing countries. Specifically, the paper analyzes the fac- tors that influence cashew farmers’ decisions to participate in CF, and the impact of participation on farmers’ performance. We employ a recently developed switch- ing regression model with endogenous explanatory variables and endogenous switch- ing to control for selection bias caused by observable and unobservable factors. The empirical results show that participation in CF significantly increases labor produc- tivity and price margins, as well as cashew yields, and net revenues. A disaggregated analysis of the sample into farm size categories reveals that small-sized cashew farms tend to benefit more through CF, compared to medium- and large-sized farms

    Virtual reality rehabilitation in patients with chronic obstructive pulmonary disease: A randomized controlled trial

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    Purpose: This study compared the effects of inpatient-based rehabilitation program of patients with chronic obstructive pulmonary disease (COPD) using non-immersive virtual reality (VR) training with a traditional pulmonary rehabilitation program. The aims of this study were to determine 1) whether rehabilitation featuring both VR as well as exercise training provides benefits over exercise training (ET) alone and 2) whether rehabilitation featuring VR training instead of exercise training provides equivalent benefits. Patients and Methods: The study recruited 106 patients with COPD to a 2-week high-intensity, five times a week intervention. Randomized into three groups, 34 patients participated in a traditional pulmonary rehabilitation program including endurance exercise training (ET), 38 patients participated in traditional pulmonary rehabilitation, including both endurance exercise training and virtual reality training (ET+VR) and 34 patients participated in pulmonary rehabilitation program including virtual reality training but no endurance exercise training (VR). The traditional pulmonary rehabilitation program consisted of fitness exercises, resistance respiratory muscle and relaxation training. Xbox 360® and Kinect® Adventures software were used for the VR training of lower and upper body strength, endurance, trunk control and dynamic balance. Comparison of the changes in the Senior Fitness Test was the primary outcome. Analysis was performed using linear mixed-effects models. Results: The comparison between ET and ET+VR groups showed that ET+VR group was superior to ET group in Arm Curl (p&lt;0.003), Chair stand (p&lt;0.008), Back scratch (p&lt;0.002), Chair sit and reach (p&lt;0.001), Up and go (p&lt;0.000), 6-min walk test (p&lt;0.011). Whereas, the comparison between ET and VR groups showed that VR group was superior to ET group in Arm Curl (p&lt;0.000), Chair stand (p&lt;0.001), 6-min walk test (p&lt;0.031). Conclusion: Results suggest that pulmonary rehabilitation program supplemented with VR training is beneficial intervention to improve physical fitness in patients with COPD

    Modelling of a Two-Signal SFQ Detection Scheme for the Readout of Superconducting Nanowire Single Photon Detectors

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    We present a two-signal single flux quantum (SFQ) detection scheme for the purpose of reading out two pixels of a superconducting nanowire single photon detector (SNSPD). The circuit is based on a coincidence buffer element which is able to output a signal when both of its input lines are triggered. The circuit model for the SNSPD element is simulated in SPICE and optimized to match the experimental SNSPD response data. The two-signal detection scheme is simulated using JSIM which allows for the simulation of Josephson junction elements in a circuit. We demonstrate a model of the two-signal circuit operating with two simulated SNSPD pixel inputs and investigate the response of the scheme when a phase shift is applied to one of the inputs. The scheme shows potential as a useful coincidence detector of single photons. We also present preliminary experimental results of nanobridge-based Josephson junctions to be used in the realization of the coincidence detector circuit. Evidence of the nanobridges exhibiting Josephson behavior (SQUID modulation) are presented

    Integrated Joule switches for the control of current dynamics in parallel superconducting strips

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    Understanding and harnessing the physics of the dynamic current distribution in parallel superconducting strips holds the key to creating next generation sensors for single molecule and single photon detection. Non-uniformity in the current distribution in parallel superconducting strips leads to low detection efficiency and unstable operation, preventing the scale up to large area sensors. Recent studies indicate that non-uniform current distributions occurring in parallel strips can be understood and modeled in the framework of the generalized London model. Here we build on this important physical insight, investigating an innovative design with integrated superconducting-to-resistive Joule switches to break the superconducting loops between the strips and thus control the current dynamics. Employing precision low temperature nano-optical techniques, we map the uniformity of the current distribution before- and after the resistive strip switching event, confirming the effectiveness of our design. These results provide important insights for the development of next generation large area superconducting strip-based sensors
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