921 resultados para Heat Stress


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PSIIPSIILHCIIPSIIPSII 1PSIIPSIPSII 2PSIPSILHCIPSIPSI 3PSII;CP43CP47;QAQR;PSII 4FoFo 5ChlaChlbC678 C684 6LHCIIPSIILHCIIVG28PSIILHCII249-Mutant,PSII LHCIIPSII LHCIIPSII 7LHCII680nmLHCIILHCII 8P680>Pheo>Chla>-CarDlD2D2D1

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IIPSIIPSIIPSIIQA-PSIIPSII 1.PS II PSIIFv/FmFv/Fm5-15% 2.QA-QB PQQBQA-QB(160 ms)(2 ms)S2QA- 4sQAQBPQQBQA-S25II 3. 77K580nm436nmPS IF725F751IPBSPS IIII643nmPBSPS IIIIIICP43CP47 .TLS2QA-S2QB-S2QA-S2QB-TLPSIIQB/QB-QAQBQAQB 5. OJIPKSTLS1S2S2S3OJIP

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Polysaccharides isolated from Porphyra (porphyran) have been known to have diverse biological activities, including immunomodulatory and antioxidant activities. The molecular weight-antiaging activity relationship of degraded porphyrans was examined in this study. Natural porphyran was extracted from P. haitanensis, and then was degraded into different molecular weight fractions, P1 molecular weight 49 kDa, P2 molecular weight 30 kDa, P3 molecular weight 8.2 kDa, by free radical. The influence on life span and vitality of porphyrans were carried out on Drosophila melanogaster. We found that all the degraded porphyrans and natural porphyran (P), added daily to the diet, can significantly increase the life span of D. melanogaster, except for P3. Among them, P1 exhibited the most prolonging life span activity. Furthermore, vitality of middle-aged flies (assessed by measuring their mating capacity) receiving porphyrans was increased considerably in comparison with the controls. Finally, in the heat-stress test, we observed a remarkable increase in survival time, especially in P3-diet groups. These results suggest that porphyrans may be effective in reducing the rate of the aging process and molecular weight has important influence on the effects. It seems that P1 and P2, possessed higher molecular weight, may be more useful in normal metabolic condition and P3, possessed the lowest molecular weight, may be more beneficial for D. melanogaster in stress condition. (C) 2007 Elsevier Ltd. All rights reserved.

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We investigated the independent and combined effects of experimental warming and grazing on plant species diversity on the north-eastern Tibetan Plateau, a region highly vulnerable to ongoing climate and land use changes. Experimental warming caused a 26-36% decrease in species richness, a response that was generally dampened by experimental grazing. Higher species losses occurred at the drier sites where N was less available. Moreover, we observed an indirect effect of climate change on species richness as mediated by plant-plant interactions. Heat stress and warming-induced litter accumulation are potential explanations for the species' responses to experimental warming. This is the first reported experimental evidence that climate warming could cause dramatic declines in plant species diversity in high elevation ecosystems over short time frames and supports model predictions of species losses with anthropogenic climate change.

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M66 an X-ray induced mutant of winter wheat (Triticum aestivum) cv. Guardian exhibits broad-spectrum resistance to powdery mildew (Blumeria graminis f. sp. tritici), yellow rust (Puccinia striiformis f. sp. tritici), and leaf rust (Puccinia recondita f. sp. tritici), along with partial resistance to stagnonospora nodorum blotch (caused by the necrotroph Stagonosporum nodorum) and septoria tritici blotch (caused by the hemibiotroph Mycosphaerella graminicola) compared to the parent plant Guardian. Analysis revealed that M66 exhibited no symptoms of infection following artificial inoculation with Bgt in the glasshouse after adult growth stage (GS 45). Resistance in M66 was associated with widespread leaf flecking which developed during tillering. Flecking also occurred in M66 leaves without Bgt challenge; as a result grain yields were reduced by approximately 17% compared to Guardian in the absence of disease. At the seedling stage, M66 exhibited partial resistance. M66, along with Tht mutants (Tht 12, Tht13), also exhibit increased tolerance to environmental stresses (abiotic), such as drought and heat stress at seedling and adult growth stages, However, adult M66 exhibited increased susceptibility to the aphid Schizaphis graminum compared to Guardian. Resistance to Bgt in M66 was characterized with increased and earlier H2O2 accumulation at the site of infection which resulted in increased papilla formation in epidermal cells, compared to Guardian. Papilla formation was associated with reduced pathogen ingress and haustorium formation, indicating that the primary cause of resistance in M66 was prevention of pathogen penetration. Heat treatment at 46 C prior to challenge with Bgt also induced partial disease resistance to Blumeria graminis f. sp. tritici in Guardian and M66 seedlings. This was characterized by a delay in primary infection, due to increased production of ROS species, such as hydrogen peroxide, ROS-scavenging enzymes and Hsp70, resulting in cross-linking of cell wall components prior to inoculation. This actively prevented the fungus from penetrating the epidermal cell wall. Proteomics analysis using 2-D gel electrophoresis identified primary and secondary disease resistance effects in M66 including detection of ROS scavenging enzymes (4, 24 hai), such as ascorbate peroxidase and a superoxidase dismutase isoform (CuZnSOD) in M66 which were absent from Guardian. Chitinase (PR protein) was also upregulated (24 hai) in M66 compared to Guardian.Monosomic and ditelosomic analysis of M66 revealed that the mutation in M66 is located on the long arm of chromosome 2B (2BL). Chromosome 2BL is known to have key genes involved in resistance to pathogens such as those causing stripe rust and powdery mildew. The TaMloB1 gene, an orthologue of the barley Mlo gene, is also located on chromosome 2BL. Sanger sequencing of part of the coding sequence revealed no deletions in the TaMloB1 gene between Guardian and M66.

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<p>When a subject is heated, the stimulation of temperature-sensitive nerve endings in the skin, and the raising of the central body temperature, results in the reflex release of sympathetic vasoconstrictor tone in the skin of the extremities, causing a measurable temperature increase at the site of release. In the sympathetic release test, the subject is gently heated by placing the feet and calves in a commercially available foot warming pouch or immersing the feet and calves in warm water and wrapping the subject in blankets. Skin blood flow is estimated from measurements of skin temperature in the fingers. Normally skin temperature of the fingers is 65-75 degrees F in cool conditions (environmental temperature: 59-68 degrees F) and rises to 85-95 degrees F during body heating. Deviations in this pattern may mean that there is abnormal sympathetic vasoconstrictor control of skin blood flow. Abnormal skin blood flow can substantially impair an individual's ability to thermoregulate and has important clinical implications. During whole body heating, the skin temperature from three different skin sites is monitored and oral temperature is monitored as an index of core temperature. Students determine the fingertip temperature at which the reflex release of sympathetic activity occurs and its maximal attainment, which reflects the vasodilating capacity of this cutaneous vascular bed. Students should interpret typical sample data for certain clinical conditions (Raynaud's disease, peripheral vascular disease, and postsympathectomy) and explain why there may be altered skin blood flow in these disorders.</p>

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Dissertation presented to obtain the Ph.D degree in Engineering Sciences and Technology.

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Please consult the paper edition of this thesis to read. It is available on the 5th Floor of the Library at Call Number: Z 9999 B56 M68 2007

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Sarco(endo)plasmic reticulum calcium ATPase (SERCA) is a transmembrane protein whose function is regulated by its immediate lipid environment (annulus). The composition of the annulus is currently unknown or its susceptibility to a high saturated fat diet (HSFD). Furthermore it is uncertain if HSFD can protect SERCA from thermal stress. The purpose of the study was to determine SERCA annular lipid composition, resulting impact of a HSFD, and in turn, influence on SERCA activity with and without thermal stress. The major findings were annular lipids were shorter and more saturated compared to whole homogenate and HSFD had no effect on annular lipid composition or SERCA activity with and without thermal stress. Both average chain length and unsaturation index were positively correlated with SERCA activity with and without thermal stress. These findings suggest that annular lipid composition is different than whole homogenate and its composition appears to be related to SERCA function.

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The combined effects of shoot pruning (one or two stems) and inflorescence thinning (five or ten flowers per inflorescence) on greenhouse tomato yield and fruit quality were studied during the dry season (DS) and rainy season (RS) in Central Thailand. Poor fruit set, development of undersized (mostly parthenocarpic) fruits, as well as the physiological disorders blossom-end rot (BER) and fruit cracking (FC) turned out to be the prevailing causes deteriorating fruit yield and quality. The proportion of marketable fruits was less than 10% in the RS and around 65% in the DS. In both seasons, total yield was significantly increased when plants were cultivated with two stems, resulting in higher marketable yields only in the DS. While the fraction of undersized fruits was increased in both seasons when plants were grown with a secondary stem, the proportions of BER and FC were significantly reduced. Restricting the number of flowers per inflorescence invariably resulted in reduced total yield. However, in neither season did fruit load considerably affect quantity or proportion of the marketable yield fraction. Inflorescence thinning tended to promote BER and FC, an effect which was only significant for BER in the RS. In conclusion, for greenhouse tomato production under climate conditions as they are prevalent in Central Thailand, the cultivation with two stems appears to be highly recommendable whereas the measures to control fruit load tested in this study did not proof to be advisable.

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El trabajo exige en el individuo una serie de esfuerzos fisiolgicos que implican el uso de los componentes del sistema osteo-muscular, cardiovascular y metablico, definindose as la carga fsica de trabajo. El objetivo fue determinar la respuesta fisiolgica a la exposicin a calor y carga fsica en trabajadores operadores de hornos de coquera. El estudio se realiz en once trabajadores expuestos a carga fsica y a calor en hornos de coquera. Se realiz la medicin de capacidad mxima de trabajo (VO2mx), medicin de consumo calrico y respuesta cardiovascular a la carga trmica y medicin de niveles de hidratacin. No obstante de su alta capacidad de trabajo y desempeo fsico de los horneros, el trabajo de deshorne se califica como extremadamente duro muy duro o intenso. Se recomienda intervenir tecnolgicamente el sistema de trabajo de deshorne mediante mecanizacin de las tareas.

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La exposicin a altas temperaturas en ambientes laborales conlleva a cambios fisiolgicos que se manifiestan como mecanismos de compensacin a la alteracin del equilibrio homeosttico corporal. El propsito del presente estudio fue determinar los cambios y el comportamiento de variables fisiolgicas a travs de frecuencia cardiaca, densidad urinaria, temperatura corporal y tasa de sudoracin, en dos escenarios con condiciones trmicas ambientales diferentes definidas por la exposicin (grupo expuesto y no expuesto). Adicional, en dos reas de trabajo diferentes correspondientes al proceso de fundicin del acero, una de ellas, Horno electrico donde se hace la fusin de la chatarra y dems materias primas, obteniendo as el acero liquido, el cual se vuelca en el Horno Cuchara y en este, libre ya de escoria se realiza el afino y ajuste definitivo de la composicin qumica del acero. Objetivos: Identificar la relacin de las respuestas fisiolgicas a carga fsica y trmica, comparar las respuestas funcionales registradas en el grupo expuestos y no expuestos y contribuir a la introduccin de nuevos indicadores para evaluar carga e intensidad de trabajo con fines de normalizacin ergonmica. Mtodo: Investigacin experimental en una muestra de 30 trabajadores evaluados en dos condiciones ambientales diferentes. La temperatura oral se registr al inicio de la jornada y con intervalos de toma de 3 horas. La frecuencia cardiaca (HR) se registr durante las 8 horas de trabajo continuas con pulsometra. Igualmente, se estim la sudoracin por prdida de masa corporal entre el inicio y el final de la jornada laboral teniendo en cuenta ingestas y perdidas. El procesamiento estadstico se realiz con el programa SPSS v. 20.0, calculndose medidas de tendencia central y dispersin, prueba de wilconxon para las variables dependientes y correlacin para identificar asociaciones. Para todos los clculos se asumi p <0,05. Resultados: No se observaron diferencias significativas frente a la variacin de la frecuencia cardiaca (media y mxima), la tasa de sudoracin y la densidad urinaria. A pesar de que no hubo diferencias significativas en la variacin de la temperatura corporal en horno cuchara, si se observ una diferencia significativa en el horno elctrico Conclusin: Aunque no se encontraron diferencias estadsticamente significativas en la mayora de las variables, es un hecho que la exposicin a temperaturas elevadas extremas tiene un impacto en el comportamiento fisiolgico del organismo. Futuros estudios deben considerar la posibilidad de estandarizar protocolos que permitan la exposicin trmica basada en el perfil particular de cada trabajador.

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La construccin es una de las industrias que mayores accidentes laborales genera, en esta investigacin se realiz un anlisis retrospectivo para determinar si existe alguna relacin entre la ocurrencia de accidentes y la fecha de entrega de una meta, debido al incremento en la cantidad de trabajo expresado por la cantidad de das y horas extras trabajados, se cuenta con informacin de la accidentalidad de cinco empresas constructoras de un gran proyecto vial en Colombia en los aos de 2012 y 2013. Se analiz la informacin correspondiente a la nmina de las mismas empresas, con el valor de la nmina mensual, el valor de las incapacidades mensuales y la cantidad de trabajadores por cada empresa en cada periodo. El manejo de los datos se hizo con EXCEL y el anlisis estadstico con STATA 11.1, se us la correlacin de Spearman para encontrar la relacin entre la cantidad de accidentes acumulados y: la cantidad acumulada de das trabajados en cada mes, la cantidad acumulada de horas extras trabajadas mensualmente y el costo acumulado en porcentaje de la nmina mensual, encontrndose en todos los casos una relacin lineal. Por otra parte, se realiz una prueba binomial para establecer la relacin de la fecha de entrega de la meta con la accidentalidad 30 das antes y despus, encontrando que la accidentalidad aumenta en la proximidad previa a la entrega de la meta

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The prolonged season of everbearing strawberries causes vegetative growth and fruiting to coincide, so the influence of the environment on the balance of assimilate partitioning between vegetative and reproductive growth is important for optimised long-season production. Fruiting patterns were evaluated over three seasons for the everbearing strawberry 'Everest'. A range of temperatures (15-27 degrees C) was studied in the first season to establish a temperature response curve. Detailed transfer treatments in the second and third seasons gave insight into heat-induced cropping troughs ('thermo-dormancy'). The detrimental effect on yield of thermo-dormancy was prevented by cool night-time temperature during the periods of heat stress, a treatment that resulted in the largest total fruit fresh weight and overall yield. The highest yields were recorded for plants grown between 18 and 23 degrees C. At higher temperatures fruit number increased, but fruit weight decreased. The importance of night-time temperature in optimising long-season fruit production has significance for commercial production, in which protected cropping tends to increase average temperature through the season.

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Producing projections of future crop yields requires careful thought about the appropriate use of atmosphere-ocean global climate model (AOGCM) simulations. Here we describe and demonstrate multiple methods for calibrating climate projections using an ensemble of AOGCM simulations in a perfect sibling framework. Crucially, this type of analysis assesses the ability of each calibration methodology to produce reliable estimates of future climate, which is not possible just using historical observations. This type of approach could be more widely adopted for assessing calibration methodologies for crop modelling. The calibration methods assessed include the commonly used delta (change factor) and nudging (bias correction) approaches. We focus on daily maximum temperature in summer over Europe for this idealised case study, but the methods can be generalised to other variables and other regions. The calibration methods, which are relatively easy to implement given appropriate observations, produce more robust projections of future daily maximum temperatures and heat stress than using raw model output. The choice over which calibration method to use will likely depend on the situation, but change factor approaches tend to perform best in our examples. Finally, we demonstrate that the uncertainty due to the choice of calibration methodology is a significant contributor to the total uncertainty in future climate projections for impact studies. We conclude that utilising a variety of calibration methods on output from a wide range of AOGCMs is essential to produce climate data that will ensure robust and reliable crop yield projections.