984 research outputs found
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Effect of whey protein isolate on rehydration after exercise
Studies have examined adding protein to carbohydrate-electrolyte rehydration drinks, but the effects of protein in isolation remain unknown. Ten subjects completed two trials in which they were dehydrated (~2% of pre-exercise body mass) by intermittent cycling in the heat. Subjects then rehydrated (150% total mass loss) over 1 h with mineral water (W) or mineral water plus 20 g¡L-1 whey protein isolate (WP) and remained in the laboratory for a further 4 h. Blood and urine samples were provided pre-exercise, post-exercise, post-rehydration and every hour thereafter. From blood samples, serum osmolality, change in plasma volume and plasma albumin content was determined, whilst the volume and osmolality of urine samples were determined. There was no difference between trials for total urine volume (W: 1234 (358) mL; WP: 1306 (268) mL; P=0.409), drink retention (W: 40 (14) %; WP: 37 (14) %; P=0.322) or net fluid balance (W: -605 (318) mL; WP: -660 (274) mL; P=0.792) 4 h post-rehdyration. Plasma volume was greater 3 and 4 h post-drinking during WP and plasma albumin content relative to pre-exercise was increased 1-4 h post-drinking in WP only. These results suggest addition of 20 g¡L-1 whey protein isolate neither enhances nor inhibits post-exercise rehydration, when a volume equivalent to 150% of sweat losses is ingested in 1 h. As post-exercise nutritional requirements are multifactorial (rehydration, glycogen resynthesis, myofibrillar/ mitochondrial protein synthesis), these data demonstrate that when post-exercise protein intake might benefit recovery or adaptation, this can be achieved without compromising rehydration
Vacuum phototriodes for the CMS electromagnetic calorimeter endcap
The measurement of scintillation light from the lead tungstate crystals of the Compact Muon Solenoid (CMS) electromagnetic calorimeter (ECAL) poses a substantial technical challenge, particularly in the endcap regions, where the radiation levels are highest. The photodetectors must be fast, sensitive, radiationhard, and operate with significant internal gain in a magnetic field of 4 Tesla. The measured performance characteristics of the first batches of series production vacuum phototriodes (VPT), developed to satisfy the needs of CMS, will be described
Recognition of Face Identity and Emotion in Expressive Specific Language Impairment
Objective: To study face and emotion recognition in children with mostly expressive specific language impairment (SLI-E). Subjects and Methods: A test movie to study perception and recognition of faces and mimic-gestural expression was applied to 24 children diagnosed as suffering from SLI-E and an age-matched control group of normally developing children. Results: Compared to a normal control group, the SLI-E children scored significantly worse in both the face and expression recognition tasks with a preponderant effect on emotion recognition. The performance of the SLI-E group could not be explained by reduced attention during the test session. Conclusion: We conclude that SLI-E is associated with a deficiency in decoding non-verbal emotional facial and gestural information, which might lead to profound and persistent problems in social interaction and development. Copyright (C) 2012 S. Karger AG, Base
Tidal Forces in Reissner-NordstrĂśm Spacetimes
We analyze the tidal forces produced in the spacetime of Reissner-Nordstr\"om black holes. We point out that the radial component of the tidal force changes sign just outside the event horizon if the charge-to-mass ratio is close to unlike in Schwarzschild spacetime of uncharged black holes, and that the angular component changes sign between the outer and inner horizons. We solve the geodesic deviation equations for radially falling bodies towards the charged black hole. We find, for example, that the radial component of the geodesic deviation vector starts decreasing inside the event horizon unlike in the Schwarzschild case
Influence of training status on high-intensity intermittent performance in response to β-alanine supplementation
Recent investigations have suggested that highly trained athletes may be less responsive to the ergogenic effects of β-alanine (BA) supplementation than recreationally active individuals due to their elevated muscle buffering capacity. We investigated whether training status influences the effect of BA on repeated Wingate performance. Forty young males were divided into two groups according to their training status (trained: T, and non-trained: NT cyclists) and were randomly allocated to BA and a dextrose-based placebo (PL) groups, providing four experimental conditions: NTPL, NTBA, TPL, TBA. BA (6.4 g day-1 ) or PL was ingested for 4 weeks, with participants completing four 30-s lower-body Wingate bouts, separated by 3 min, before and after supplementation. Total work done was significantly increased following supplementation in both NTBA (p = 0.03) and TBA (p = 0.002), and it was significantly reduced in NTPL (p = 0.03) with no difference for TPL (p = 0.73). BA supplementation increased mean power output (MPO) in bout 4 for the NTBA group (p = 0.0004) and in bouts 1, 2 and 4 for the TBA group (p ⤠0.05). No differences were observed in MPO for NTPL and TPL. BA supplementation was effective at improving repeated high-intensity cycling performance in both trained and non-trained individuals, highlighting the efficacy of BA as an ergogenic aid for high-intensity exercise regardless of the training status of the individual
(Micro)evolutionary changes and the evolutionary potential of bird migration
Seasonal migration is the yearly long-distance movement of individuals between their breeding and wintering grounds. Individuals from nearly every animal group exhibit this behavior, but probably the most iconic migration is carried out by birds, from the classic V-shape formation of geese on migration to the amazing nonstop long-distance flights undertaken by Arctic Terns Sterna paradisaea. In this chapter, we discuss how seasonal migration has shaped the field of evolution. First, this behavior is known to turn on and off quite rapidly, but controversy remains concerning where this behavior first evolved geographically and whether the ancestral state was sedentary or migratory (Fig. 7.1d, e). We review recent work using new analytical techniques to provide insight into this topic. Second, it is widely accepted that there is a large genetic basis to this trait, especially in groups like songbirds that migrate alone and at night precluding any opportunity for learning. Key hypotheses on this topic include shared genetic variation used by different populations to migrate and only few genes being involved in its control. We summarize recent work using new techniques for both phenotype and genotype characterization to evaluate and challenge these hypotheses. Finally, one topic that has received less attention is the role these differences in migratory phenotype could play in the process of speciation. Specifically, many populations breed next to one another but take drastically different routes on migration (Fig. 7.2). This difference could play an important role in reducing gene flow between populations, but our inability to track most birds on migration has so far precluded evaluations of this hypothesis. The advent of new tracking techniques means we can track many more birds with increasing accuracy on migration, and this work has provided important insight into migration's role in speciation that we will review here
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Dense, fast, radiation-tolerant Fluoro-Hafnate glass scintillators for electromagnetic calorimeters in high energy physics
Over 200 different compositions of heavy metal fluoride glasses have been produced and evaluated as possible candidates for the active medium in homogeneous electromagnetic calorimeters for high energy particles. Promising glasses, based on mixtures containing hafnium fluoride, have densities of 6 g/cm^3, radiation lengths of 1.6 cm, and good optical transmission from the UV to the IR. Glasses containing the Ce3+ ion are fast scintillators, with properties similar to those of pure cerium fluoride crystal. We have made glasses which have up to 14% of the light yield of CeF3, fast scintillation characterised by typical exponential decay constants of 10 ns and 25 ns, and a temperature dependence of light yield of -0.4%/C over the range -10C to 60C. We have carried out a detailed investigation of the effects of gamma irradiation (up to doses of 6kGy) on the optical transmission, and systematic studies into the role of indium and other elements on radiation tolerance and light yield. Some glasses have shown complete optical annealing of radiation-induced absorbance when exposed to UV light.PPAR
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Illusory Memories of Emotionally Charged Words in Autism Spectrum Disorder: Further Evidence for Atypical Emotion Processing Outside the Social Domain
Recent evidence suggests that individuals with ASD may not accumulate distinct representations of emotional information throughout development. On the basis of this observation we predicted that such individuals would not be any less likely to falsely remember emotionally significant as compared to neutral words when such illusory memories are induced by asking participants to study lists of words that are orthographically associated to these words. Our findings showed that typical participants are far less likely to experience illusory memories of emotionally charged as compared to neutral words. Individuals with ASD, on the other hand, did not exhibit this emotional modulation of false memories. We discuss this finding in relation to the role of emotional processing atypicalities in ASD
Effect of β-alanine supplementation on 20 km cycling time trial performance
The effects of β-alanine supplementation on high-intensity cycling performance and capacity have been evaluated, although the effects on longer duration cycling performance are unclear. Nineteen UK category 1 male cyclists completed four 20 km cycling time trials, two before and two after supplementation with either 6.4 gâ˘d -1 β-alanine (n = 10; BA) or a matched placebo (n = 9; P). Performance time for the 20 km time trial and 1 km split times were recorded. There was no significant effect of β-alanine supplementation on 20 km time trial performance (BA-pre 1943 Âą 129 s; BA-post 1950 Âą 147 s; P-pre 1989 Âą 106 s; P-post 1986 Âą 115 s) or on the performance of each 1 km split. The effect of β-alanine on 20 km time trial performance was deemed unclear as determined by magnitude based inferences. Supplementation with 6.4 gâ˘d -1 of β-alanine for 4 weeks did not affect 20 km cycling time trial performance in well trained male cyclists
Schwarzschild spacetime under generalised Gullstrand-Painlev\'e slicing
We investigate a foliation of Schwarzschild spacetime determined by observers
freely falling in the radial direction. This is described using a
generalisation of Gullstrand-Painlev\'e coordinates which allows for any
possible radial velocity. This foliation provides a contrast with the usual
static foliation implied by Schwarzschild coordinates. The -dimensional
spaces are distinct for the static and falling observers, so the embedding
diagrams, spatial measurement, simultaneity, and time at infinity are also
distinct, though the -dimensional spacetime is unchanged. Our motivation is
conceptual understanding, to counter Newton-like viewpoints. In future work,
this alternate foliation may shed light on open questions regarding quantum
fields, analogue gravity, entropy, energy, and other quantities. This article
is aimed at experienced relativists, whereas a forthcoming series is intended
for a general audience of physicists, mathematicians, and philosophers.Comment: 21 pages, 5 figures, to appear as chapter 9 in Cacciatori, G\"uneysu,
and Pigola, eds. (c. 2019), Einstein equations: Physical and mathematical
aspects of general relativit
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