Efeito da sazonalidade sobre a congelação do sêmen caprino no Nordeste.

No Nordeste do Brasil, em especial no semi-árido, observa-se que o clima tem influência sobre a qualidade do sêmen. Na Embrapa Caprinos, onde há uma Central de Inseminação, verificou-se que em determinados períodos do ano não se consegue realizar o processamento do sêmen. Pesquisadores verificaram que em determinados períodos há alteração dos parâmetros bioquímicos do plasma seminal, especialmente na época seca. Foram encontrados valores de proteínas totais, frutose e ácido cítrico inferiores nessa época. O objetivo desse trabalho foi mapear o período de maior congelabilidade do sêmen de caprinos das raças Saanen, Anglo-nubiana e Pardo Alpina ao longo de dois anos de trabalho

Le plaisir de créer : élaborer des stratégies pour engager un dialogue philosophique interactif sur la notion de plaisir dans la création artistique chez les étudiants en arts plastiques au collégial

L'outil pédagogique développé dans le cadre de cette recherche appliquée se veut une stratégie pour favoriser l'engagement des étudiants en arts visuels au collégial et ainsi contrer le décrochage scolaire. Il prend la forme d'une vidéo présentant les entretiens de neuf participants issus des milieux artistiques, de l'enseignement et du milieu étudiant (cégep). La vidéo s'inspire des principes du dialogue philosophique pour diriger et approfondir la réflexion sur la notion de plaisir dans la création artistique. Le premier chapitre de ce mémoire explore le concept à la base de cette recherche: le plaisir. Différentes définitions et approches du plaisir sont présentées ainsi que l'apport du plaisir à l'enseignement des arts plastiques sur le plan de la motivation, de l'apprentissage et de la création artistique. Le concept de conscience s'articule ensuite à celui du plaisir. Le second chapitre présente donc les différents niveaux de la conscience, ses causes et fonctions et met l'accent sur l'application pédagogique en lien avec la prise de conscience et la métacognition. Ce texte accompagnateur se termine par la présentation de l'outil pédagogique (vidéo destinée aux étudiants). La sélection des participants s'est effectuée par un échantillonnage de type « boule de neige ». Les questionnaires ouverts et les entrevues semi-dirigées ont permis de recueillir les opinions des participants qui ont été analysées en les comparant aux concepts de plaisir et de conscience. Enfin, une présentation des pistes d'exploitation de l'outil pédagogique clôt le dernier chapitre. Cette analyse permet de constater l'utilisation d'une grande variété dans les définitions du plaisir chez les participants. Le plaisir est aussi associé à une source de motivation dans la création artistique, à l'amélioration de la qualité du travail et à la réalisation de soi. En favorisant la prise de conscience du plaisir dans la création artistique, cet outil pédagogique offre une arme supplémentaire dans la lutte au décrochage scolaire. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Plaisir, Création artistique, Dialogue philosophique, Collégial, Prise de conscience, Motivation, Outil pédagogique, DVD, Vidéo

Curling deformations in cement paste slabs and effects of shrinkage reducing admixtures

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1998.Includes bibliographical references (leaves 145-148).by Eloy E. Martinez.M.S

Reduced mitochondrial efficiency explains mismatched growth and metabolic rate at supraoptimal temperatures.

The relationship between whole-organism growth and metabolism is generally assumed to be positive and causative; higher metabolic rates support higher growth rates. In Manduca sexta, existing data demonstrate a deviation from this simple prediction: at supraoptimal temperatures for larval growth, metabolic rate keeps increasing while growth rate is decreasing. This mismatch presumably reflects the rising “cost of maintenance” with temperature. Precisely what constitutes this cost is not clear, but we suspect the efficiency with which mitochondria harness oxygen and organic substrates into cellular energy (ATP) is key. We tested this by integrating existing data on M. sexta growth and metabolism with new data on mitochondrial bioenergetics across the temperature range 14°–42°C. Across this range, our measure of mitochondrial efficiency closely paralleled larval growth rates. At supraoptimal temperatures for growth, mitochondrial efficiency was reduced, which could explain the mismatch between growth and metabolism observed at the whole-organism level

Mitochondrial Energetics of Benthic and Pelagic Antarctic Teleosts

Antarctic fauna are highly adapted to the frigid waters of the Southern Ocean. This study describes the in vitro temperature sensitivity of oxygen consumption rates measured in liver mitochondria from the pelagic notothenioid Pleuragramma antarcticum between 5 and 35 C. Oxygen fluxes were measured after the addition of millimolar levels of pyruvate, malate, succinate and glutamate (state II, LEAK) and saturating levels of ADP [state III, oxidative phosphorylation (OXPHOS)]. State III respiration significantly decreased above 18.7 C. A comparison of the oxidative capacities among P. antarcticum and other notothenioids showed significant differences in state III respiration, where benthic species exhibited about 50 % lower rates than P. antarcticum . In addition, state III respiration rates normalized per milligram of mitochondrial protein of P. antarcticum were up to eight times higher than state III rates reported in the literature for other notothenioids. The comparatively high respiration rates measured in this study may be explained by our approach, which engaged both complexes I and II under conditions of oxidative phosphorylation. State III rates of independently activated complexes I and II were found to range from 42 to 100 % of rates obtained when both complexes were activated simultaneously in the same species. The remarkable tolerance of P. antarcticum OXPHOS toward warmer temperatures was unexpected for an Antarctic stenotherm and may indicate that thermal sensitivity of their mitochondria is not the driving force behind their stenothermy

Mitochondrial energetics of benthic and pelagic Antarctic teleosts.

Antarctic fauna are highly adapted to the frigid waters of the Southern Ocean. This study describes the in vitro temperature sensitivity of oxygen consumption rates measured in liver mitochondria from the pelagic notothenioid Pleuragramma antarcticum between 5 and 35 C. Oxygen fluxes were measured after the addition of millimolar levels of pyruvate, malate, succinate and glutamate (state II, LEAK) and saturating levels of ADP [state III, oxidative phosphorylation (OXPHOS)]. State III respiration significantly decreased above 18.7 C. A comparison of the oxidative capacities among P. antarcticum and other notothenioids showed significant differences in state III respiration, where benthic species exhibited about 50 % lower rates than P. antarcticum . In addition, state III respiration rates normalized per milligram of mitochondrial protein of P. antarcticum were up to eight times higher than state III rates reported in the literature for other notothenioids. The comparatively high respiration rates measured in this study may be explained by our approach, which engaged both complexes I and II under conditions of oxidative phosphorylation. State III rates of independently activated complexes I and II were found to range from 42 to 100 % of rates obtained when both complexes were activated simultaneously in the same species. The remarkable tolerance of P. antarcticum OXPHOS toward warmer temperatures was unexpected for an Antarctic stenotherm and may indicate that thermal sensitivity of their mitochondria is not the driving force behind their stenothermy

Mitochondrial Energetics of Benthic and Pelagic Antarctic Teleosts

Antarctic fauna are highly adapted to the frigid waters of the Southern Ocean. This study describes the in vitro temperature sensitivity of oxygen consumption rates measured in liver mitochondria from the pelagic notothenioid Pleuragramma antarcticum between 5 and 35 C. Oxygen fluxes were measured after the addition of millimolar levels of pyruvate, malate, succinate and glutamate (state II, LEAK) and saturating levels of ADP [state III, oxidative phosphorylation (OXPHOS)]. State III respiration significantly decreased above 18.7 C. A comparison of the oxidative capacities among P. antarcticum and other notothenioids showed significant differences in state III respiration, where benthic species exhibited about 50 % lower rates than P. antarcticum . In addition, state III respiration rates normalized per milligram of mitochondrial protein of P. antarcticum were up to eight times higher than state III rates reported in the literature for other notothenioids. The comparatively high respiration rates measured in this study may be explained by our approach, which engaged both complexes I and II under conditions of oxidative phosphorylation. State III rates of independently activated complexes I and II were found to range from 42 to 100 % of rates obtained when both complexes were activated simultaneously in the same species. The remarkable tolerance of P. antarcticum OXPHOS toward warmer temperatures was unexpected for an Antarctic stenotherm and may indicate that thermal sensitivity of their mitochondria is not the driving force behind their stenothermy

Oral History Transcript - Eloy Z. Gonzalez

https://scholarworks.utrgv.edu/chapsoralhistories/1033/thumbnail.jp

Seguimiento del hábitat dominado por Zoanthus pulchellus (Cnidaria: Anthozoa) en el intermareal de Punta del Hidalgo (Tenerife)

El calentamiento de los océanos asociado al cambio climático está provocando cambios en la distribución de las comunidades marinas. En Canarias este calentamiento ha favorecido que organismos termófilos como el zoantídeo Zoanthus pulchellus proliferen llegando en algunos casos a dominar el hábitat. En este estudio se evaluó el patrón de distribución de dicha especie y su influencia sobre otros organismos sésiles de las comunidades bentónicas en la zona dominada por el zoantídeo en el intermareal de Punta del Hidalgo, registrándose conjuntamente parámetros de calidad del agua (clorofila A, materia orgánica particulada). La cobertura del zoantídeo no se distribuyó de forma homogénea en toda la extensión del hábitat Zoanthus, siendo mayor en el intermareal medio y en las zonas centrales de la extensión. Las comunidades de macroalgas erectas ocupaban la mayor parte de sustrato en el intermareal inferior, y en la escala horizontal del intermareal medio aparecieron unas zonas de transición donde las densidades del zoantídeo disminuyeron dando oportunidad a otros organismos sésiles. El seguimiento temporal realizado mostró diferencias en el Borde Este de la zona Zoanthus entre 2020 y 2021 a nivel de comunidad, debido a la reducción de las coberturas macroalgas y el aumento de sustrato libre, mientras que no se encontró relación de estas variaciones con los parámetros de calidad del agua. Aunque los resultados del estudio no demuestran un aumento de la población de Z. pulchellus en una escala temporal de un año, resulta de utilidad como un punto inicial para el seguimiento a largo plazo de los hábitats dominados por zoantídeos y sus efectos sobre las comunidades intermareales en Canarias, en un contexto del calentamiento oceánico.Ocean warming associated with climate change is causing changes in the distribution of marine communities. In the Canary Islands, such warming has favoured the proliferation of thermophilic organisms such as the zoantharian Zoanthus pulchellus, which in some cases has come to dominate the habitat. In this study we evaluated the distribution pattern of this species and its influence on other sessile organisms of benthic communities in the zone dominated by the zoantharian in the intertidal of Punta del Hidalgo, as well as some water quality parameters (chlorophyll A, particulate organic matter). Zoantharian coverage was not evenly distributed throughout the Zoanthus habitat range, being higher in the mid-intertidal and central areas of the patch. Erect macroalgal communities occupied most of the substrate in the lower intertidal, and on the horizontal scale of the mid-intertidal transition zones appeared where zoantharian densities decreased, giving opportunities to other sessile organisms. Temporal monitoring showed differences in the Eastern edge of the Zoanthus zone between 2020 and 2021 at the community level, due to a reduction in macroalgal cover and an increase in free substrate, while no relationship was found between these variations and water quality parameters. Although results of the study do not demonstrate a population increase of Z. pulchellus on a one-year time scale, it is useful as a starting point for a long-term monitoring of zoantharian-dominated habitats and their effects on intertidal communities in the Canary Islands in the context of ocean warming