467 research outputs found
Relación de la ingesta a largo plazo de macronutrientes en las hormonas anabólicas-catabólicas de jugadoras de voleibol elite
[EN] Introduction: Specific macronutrient distribution and training can alter acute and chronic hormone behavior and, subsequently, sport performance. Objective: The main aim was to examine relationships between dietary intake and anabolic/catabolic hormone response in elite female volleyball players during a 29-week season. Methods: Twenty-two elite female volleyballers (26.4 ± 5.6 years; 178 ± 9 cm; 67.1±7.5 kg) had dietary intake (seven-day dietary recall and food frequency questionnaire), blood concentration of anabolic/catabolic hormones concentration, physical performance, and body composition assessed at four time points: a) T1: baseline/pre-testing; b) T2: eleven weeks after T1; c) T3: ten weeks after T2; and d) T4: eight weeks after T3. Hormones evaluated were: total testosterone (TT), free testosterone (FT) adrenocorticotropic hormone (ACTH), and cortisol (C), along with hormone ratios. Results: Positive correlations were observed between carbohydrate/protein ratio with ΔFT (r = 0.955; p 0.05) in body mass or body mass index at any time point, and the sum of six skinfolds improved (p < 0.05) from T1 (86.5 ± 6.9 mm) to T4 (75.2 ± 5.6 mm) as did muscle mass (T1: 28.9 ± 0.7 kg vs T4: 30.1 ± 0.8 kg). Vertical jump, spike-jump and speed improved (p < 0.05) from T1 to T4. Conclusions: A high carbohydrate/protein ratio was associated with positive changes in anabolism, while high protein and low carbohydrates (CHO) were associated with an attenuated anabolic response[ES] Introducción: la distribución específica de macronutrientes y el entrenamiento pueden alterar el comportamiento agudo y crónico de las hormonas y, posteriormente, el rendimiento deportivo.
Objetivo: el objetivo principal del estudio fue examinar la relación entre la ingesta dietética y la respuesta anabólica/catabólica hormonal de jugadoras de élite de voleibol durante una temporada de 29 semanas.
Métodos: se evaluó en 22 jugadoras de élite (26,4 ± 5,6 años, 178 ± 9 cm, 67,1 ± 7,5 kg) la ingesta dietética (mediante un registro de siete días y un cuestionario de frecuencia de consumo de alimentos), la concentración de hormona anabólica/catabólica en sangre, el rendimiento físico y la composición corporal en cuatro puntos durante la temporada: a) T1: pre-pretemporada; b) T2: once semanas después de T1; c) T3: diez semanas después de T2; y d) T4: ocho semanas después de T3. Las hormonas evaluadas fueron: testosterona total (TT), testosterona libre (FT), hormona adrenocorticotropa (ACTH) y cortisol (C); se calcularon distintos ratios hormonales.
Resultados: se observaron correlaciones positivas entre la ratio carbohidratos/proteínas con ΔFT (r = 0,955; p 0,05) en la masa corporal ni en el índice de masa corporal en ningún momento, mientras que el sumatorio de seis pliegues mejoró (p < 0,05) de T1 (86,5 ± 6,9 mm) a T4 (75,2 ± 5,6 mm), así como la masa muscular (T1: 28,9 ± 0,7 kg frente a T4: 30,1 ± 0,8 kg). El salto vertical, el salto de remate y la velocidad mejoraron (p < 0,05) de T1 a T4.
Conclusión: en conclusión, una alta ratio de carbohidratos/proteínas se asoció con cambios positivos en el anabolismo, mientras que una ingesta alta de proteína y baja de CHO se asoció con una respuesta anabólica atenuada.S
Effect of Zeolitic Imidazolate Framework Topology on the Purification of Hydrogen from Coke Oven Gas
This work aims to shed light on the performance of zeolitic imidazolate frameworks for hydrogen purification from coke oven gases (COG). Using molecular simulation, we model COG as a mixture of six gases and study the effect of ZIF topology on the separation performance. To do this, we compare similar structures, e.g., ZIF-8 and ZIF-11, and focus on obtaining information that explains why they behave differently while being so similar. Simulation results show that the structure with the smallest pore size best separates hydrogen from carbon monoxide and nonpolar molecules. The adsorption of carbon dioxide is also strongly affected by the polarizability of the structure. However, the adsorption of the other components (methane, carbon monoxide, nitrogen, and oxygen) is strongly dependent on their pore size. We also provide molecular information on the effect of phase transition on hydrogen purification using ZIF-7 as an example, which drastically changes the pore volume of the structure when it changes phase. These findings will help to select high-performance ZIFs for adsorption- or screening-based hydrogen purification.</p
Influencia de los armónicos de corriente sobre las pérdidas en los transformadores de distribución monofásicos con derivación central
Dentro de los componentes más importantes de los sistemas eléctricos se encuentran los transformadores de potencia, cuya eficiencia se ve afectada por problemas de calidad de energía eléctrica presentes en las redes. Uno de los problemas al que son sensibles los transformadores es a la circulación de corrientes no sinusoidales por sus devanados, cuando alimentan cargas no lineales. Esto produce un incremento en las pérdidas y, por tanto, en la temperatura de trabajo que tienen los esfuerzos del aislamiento, y una reducción de la vida útil y de la capacidad del transformador que debe ser considerada. Para estos casos, la norma ANSI/IEEE C57.110 permite determinar la reducción de la capacidad y la corriente permisible del transformador ante cargas no lineales. En este artículo se presenta un modelo analítico basado en esta norma, se describe el procedimiento de cálculo para el caso de transformadores monofásicos con derivación central y se evalúa la influencia de los armónicos de corriente en el incremento de las pérdidas, utilizando como caso de estudio un transformador de 25 kVA para diferentes magnitudes de THD de corriente. Se desarrolla, además, un modelo en Simulink de Matlab, el cual es coincidente en sus resultados con el modelo analítico desarrollado
Controlling the polarization and vortex charge of attosecond high-harmonic beams via simultaneous spin–orbit momentum conservation
[EN]Optical interactions are governed by both spin and angular momentum conservation laws, which serve as a tool for controlling light–matter interactions or elucidating electron dynamics and structure of complex systems. Here, we uncover a form of simultaneous spin and orbital angular momentum conservation and show, theoretically and experimentally, that this phenomenon allows for unprecedented control over the divergence and polarization of extreme-ultraviolet vortex beams. High harmonics with spin and orbital angular momenta are produced, opening a novel regime of angular momentum conservation that allows for manipulation of the polarization of attosecond pulses—from linear to circular—and for the generation of circularly polarized vortices with tailored orbital angular momentum, including harmonic vortices with the same topological charge as the driving laser beam. Our work paves the way to ultrafast studies of chiral systems using high-harmonic beams with designer spin and orbital angular momentum.The authors are thankful for useful and productive conversations with E. Pisanty, C. Durfee, D. Hickstein, S. Alperin and M. Siemens. H.C.K. and M.M.M. graciously acknowledge support from the Department of Energy BES Award No. DE-FG02–99ER14982 for the experimental implementation, as well as a MURI grant from the Air Force Office of Scientific Research under Award No. FA9550–16–1–0121 for the theory. J.L.E., N.J.B. and Q.L.N. acknowledge support from National Science Foundation Graduate Research Fellowships (Grant No. DGE-1144083). C.H.-G., J.S.R. and L.P. acknowledge support from Junta de Castilla y León (SA046U16) and Ministerio de Economía y Competitividad (FIS2013–44174-P, FIS2016–75652-P). C.H.-G. acknowledges support from a 2017 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation. L.R. acknowledges support from Ministerio de Educación, Cultura y Deporte (FPU16/02591). A.P. acknowledges support from the Marie Sklodowska-Curie Grant, Agreement No. 702565. We thankfully acknowledge the computer resources at MareNostrum and the technical support provided by Barcelona Supercomputing Center (RES-AECT-2014–2–0085). This research made use of the high-performance computingresources of the Castilla y León Supercomputing Center (SCAYLE, www.scayle.es),financed by the European Regional Development Fund (ERDF). Certain commercial instruments are identified to specify the experimental study adequately. This does not imply endorsement by the National Institute of Standards and Technology (NIST) or that the instruments are the best available for the purpose
Contrasting vertical and horizontal representations of affect in emotional visual search
The final publication is available at Springer via http://dx.doi.org/ 10.3758/s13423-015-0884-6Independent lines of evidence suggest that the representation of emotional evaluation recruits both vertical and horizontal spatial mappings. These two spatial mappings differ in their experiential origins and their productivity, and available data suggest that they differ in their saliency. Yet, no study has so far compared their relative strength in an attentional orienting reaction time task that affords the simultaneous manifestation of both of them. Here we investigated this question using a visual search task with emotional faces. We presented angry and happy face targets and neutral distracter faces in top, bottom, left, and right locations on the computer screen. Conceptual congruency effects were observed along the vertical dimension supporting the ‘up=good’ metaphor, but not along the horizontal dimension. This asymmetrical processing pattern was observed when faces were presented in a cropped (Experiment 1) and whole (Experiment 2) format. These findings suggest that the ‘up=good’ metaphor is more salient and readily activated than the ‘right=good’ metaphor, and that the former outcompetes the latter when the task context affords the simultaneous activation of both mappings
Impact of Dissolved Organic Matter on Bacterial Tactic Motility, Attachment, and Transport
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