University of Trás-os-Montes and Alto Douro

About: University of Trás-os-Montes and Alto Douro is a education organization based out in Vila Real, Portugal. It is known for research contribution in the topics: Population & Context (language use). The organization has 2858 authors who have published 7146 publications receiving 138394 citations. The organization is also known as: University of Tras-os-Montes and Alto Douro & UTAD.

Photoluminescence and Quantum Yields of Urea and Urethane Cross-Linked Nanohybrids Derived from Carboxylic Acid Solvolysis

Abstract: Urea and urethane cross-linked hybrids, classed as di-ureasils and di-urethanesils, were prepared through sol−gel derived carboxylic acid solvolysis. The resulting nanohybrids were characterized by X-ray diffraction, mid-infrared spectroscopy, 29Si and 13C nuclear magnetic resonance, and photoluminescence spectroscopy and results were compared with those of similar hybrid materials obtained from the conventional sol−gel route. The results indicate a similar structure for the hybrids, independent of the synthesis process used. All the hybrids are efficient room-temperature white-light emitters with emission quantum yields between 6 and 20%. The emission quantum yields of hybrids prepared through carboxylic acid solvolysis are 27−35% higher than those calculated for the di-ureasils and di-urethanesils synthesized via the conventional sol−gel technique. This is attributed to the presence of a larger number of nonbonded NH urea- and urethane-groups in the hybrids prepared by carboxylic acid solvolysis, illust...

Effects of Pitch Area-Restrictions on Tactical Behavior, Physical, and Physiological Performances in Soccer Large-Sided Games.

Abstract: The aim of this study was to identify how pitch area-restrictions affect the tactical behavior, physical, and physiological performances of players during soccer large-sided games. A 10 vs. 9 large-sided game was performed under 3 experimental conditions: (a) restricted-spacing, the pitch was divided into specific areas where players were assigned and they should not leave it; (b) contiguous-spacing, the pitch was divided into specific areas where the players were only allowed to move to a neighboring one; (c) free-spacing, the players had no restrictions in space occupation. The positional data were used to compute players' spatial exploration index and also the distance, coefficient of variation, approximate entropy, and frequency of near-in-phase displacements synchronization of players' dyads formed by the outfield teammates. Players' physical and physiological performances were assessed by the distance covered at different speed categories, game pace, and heart rate. Most likely higher values were found in players' spatial exploration index under free-spacing conditions. The synchronization between dyads' displacements showed higher values for contiguous-spacing and free-spacing conditions. In contrast, for the jogging and running intensity zones, restricted-spacing demanded a moderate effect and most likely decrease compared with other scenarios (~20–50% to jogging and ~60–90% to running). Overall, the effects of limiting players' spatial exploration greatly impaired the coadaptation between teammates' positioning while decreasing the physical and physiological performances. These results allow for a better understanding of players' decision-making process according to specific task rules and can be relevant to enrich practice task design, such that coaches acknowledge the differential effect by using specific pitch-position area restrictions.