967 resultados para 571 Physiology
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Infrared thermography is a non-invasive technique that measures mid to long-wave infrared radiation emanating from all objects and converts this to temperature. As an imaging technique, the value of modern infrared thermography is its ability to produce a digitized image or high speed video rendering a thermal map of the scene in false colour. Since temperature is an important environmental parameter influencing animal physiology and metabolic heat production an energetically expensive process, measuring temperature and energy exchange in animals is critical to understanding physiology, especially under field conditions. As a non-contact approach, infrared thermography provides a non-invasive complement to physiological data gathering. One caveat, however, is that only surface temperatures are measured, which guides much research to those thermal events occurring at the skin and insulating regions of the body. As an imaging technique, infrared thermal imaging is also subject to certain uncertainties that require physical modeling, which is typically done via built-in software approaches. Infrared thermal imaging has enabled different insights into the comparative physiology of phenomena ranging from thermogenesis, peripheral blood flow adjustments, evaporative cooling, and to respiratory physiology. In this review, I provide background and guidelines for the use of thermal imaging, primarily aimed at field physiologists and biologists interested in thermal biology. I also discuss some of the better known approaches and discoveries revealed from using thermal imaging with the objective of encouraging more quantitative assessment.
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UANL
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UANL
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Les tudes dimagerie par rsonance magntique fonctionnelle (IRMf) ont pour prmisse gnrale lide que le signal BOLD peut tre utilis comme un succdan direct de lactivation neurale. Les tudes portant sur le vieillissement cognitif souvent comparent directement lamplitude et ltendue du signal BOLD entre des groupes de personnes jeunes et gs. Ces tudes comportent donc un a priori additionnel selon lequel la relation entre lactivit neurale et la rponse hmodynamique laquelle cette activit donne lieu restent inchange par le vieillissement. Cependant, le signal BOLD provient dune combinaison ambigu de changements de mtabolisme oxydatif, de flux et de volume sanguin. De plus, certaines tudes ont dmontr que plusieurs des facteurs influenant les proprits du signal BOLD subissent des changements lors du vieillissement. Lacquisition dinformation physiologiquement spcifique comme le flux sanguin crbral et le mtabolisme oxydatif permettrait de mieux comprendre les changements qui sous-tendent le contraste BOLD, ainsi que les altrations physiologiques et cognitives propres au vieillissement. Le travail prsent ici dmontre lapplication de nouvelles techniques permettant de mesurer le mtabolisme oxydatif au repos, ainsi que pendant lexcution dune tche. Ces techniques reprsentent des extensions de mthodes dIRMf calibre existantes. La premire mthode prsente est une gnralisation des modles existants pour lestimation du mtabolisme oxydatif voqu par une tche, permettant de prendre en compte tant des changements arbitraires en flux sanguin que des changements en concentrations sanguine dO2. Des amliorations en terme de robustesse et de prcisions sont dmontres dans la matire grise et le cortex visuel lorsque cette mthode est combine une manipulation respiratoire incluant une composante dhypercapnie et dhyperoxie. Le seconde technique prsente ici est une extension de la premire et utilise une combinaison de manipulations respiratoires incluant lhypercapnie, lhyperoxie et ladministration simultane des deux afin dobtenir des valeurs exprimentales de la fraction dextraction doxygne et du mtabolisme oxydatif au repos. Dans la deuxime partie de cette thse, les changements vasculaires et mtaboliques lis lge sont explors dans un groupe de jeunes et ans, grce au cadre conceptuel de lIRMf calibre, combin une manipulation respiratoire dhypercapnie et une tche modifie de Stroop. Des changements de flux sanguin au repos, de ractivit vasculaire au CO2 et de paramtre de calibration M ont t identifis chez les ans. Les biais affectant les mesures de signal BOLD obtenues chez les participants gs dcoulant de ces changements physiologiques sont de plus discuts. Finalement, la relation entre ces changements crbraux et la performance dans la tche de Stroop, la sant vasculaire centrale et la condition cardiovasculaire est explore. Les rsultats prsents ici sont en accord avec lhypothse selon laquelle une meilleure condition cardiovasculaire est associe une meilleure fonction vasculaire centrale, contribuant ainsi lamlioration de la sant vasculaire crbrale et cognitive.
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A recently established strain collection of freshwater microalgae native to Quebec was examined for physiological diversity. The 100 strains appeared very heterogeneous in terms of growth when they were cultured at 102 C or 222 C on the secondary effluent from a municipal wastewater treatment plant (WW) and defined BBM medium. Scatterplots were used to examine the diversity in physiology that might be present in the collection. These showed a number of interesting results. There was a fair amount of dispersion in growth rates by media type independent of temperature. Surprisingly considering that all the isolates had been initially enriched on BBM, the distribution was quite symmetrical around the iso-growth line, suggesting that enrichment on BBM did not seem to bias the cells for growth on this medium versus WW. As well, considering that all the isolates had been initially enriched at 22 C, it is quite surprising that the distribution of specific growth rates was quite symmetrical around the iso-growth line with roughly equal numbers of isolates found on either side. Thus enrichment at 22 C does not seem to bias the cells for growth at this temperature versus 10C. The scatterplots obtained when the percentage lipid of cultures grown on BBM were compared with cultures grown on WW at either 10 C or 22 C made it apparent that lipid production was favored by growth on WW at either temperature and that lipid production does not seem to be particularly favored by one temperature over the other. When the collection was queried for differences with respect to sampling location, statistical analysis showed that roughly the same degree of physiological diversity was found with samples from the two different aggregate locations.
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School of Industrial Fisheries,Cochin University of Science and Technology
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This thesis Entitled studies on the effect of toxic heavy metal mercury on the physiology and biochemistry of an estuarine crab scylla serrata (Forskal). Evaluate the toxicity of three sub lethal concentrations of mercury, viz., 0.009 mg/l, 0.02 mg/1, and 0.04 mg/l on the mud crab, Scylla serrata through bioaccumulation, and depuration studies. To characterize the biochemical responses to the sub-lethal stress of mercury in chelate muscles, abdominal muscles, hepatopancreas and gills. To study the activity pattern of acid and alkaline phosphatases in mercury-exposed crabs. To evaluate the induced changes in these tissues through histopathological studies,The Cochin backwaters is one of the most productive and biologically active backwater systems, and is the habitat of varieties of fishes, mollusks, and crustaceans, though this water body also receives tons of effluents from factories located on the banks of the river, Periyar.To study the activity levels of acid and alkaline phosphatases in crabs, at three time periods, exposed to three sub lethal concentration of mercury,
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A study of the reproductive physiology of P. (P). semisulcatus wasundertaken as this information is an essential prerequisite for brood stock development for hatchery operations, and the results are embodied in this thesis. The thesis is presented in seven chapters. The protein, lipid and carbohydrate contents of ovary were estimated for the different vitellogenic phases. The protein, lipid, carbohydrate and cholesterol contents were estimated in testes and spermatophore.The thesis present the results of induced maturation experiments by eyestalk ablation, CNS extract injection and UV rays application on immature female prawns.
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The main objective of the study is primarily to determine the magnitude of selected trace elements, the concentrations of which would possibly accelerate growth resulting in larger biomass and sustained period of exponential phase for economically viable harvest. The study on the effect of three trace elements namely Cu, Mn and Zn on two species of algae,ISOChrySiS galbana Parke and Synechocystib salina Wislouch under different conditions of salinity, PH and temperature involves several combinations for each metal, from which the relative set of conditions has been adduced. The scheme of the experiments was statistically designed for interpretation of data and factors were assessed and graded according to relative importance. The methodology adopted for data interpretation is analysis of variance by split-plot design method. The thesis has been divided into five chapters. The introductory chapter explains the relevance of the research work undertaken. Chapter 11 gives a review on the work pertaining to the above mentioned three trace elements in relation to nutrition as well as on the toxic aspects about which there is an abundance of literature. Chapter Ill presents a detailed description of the material and specialised methods followed for the study. The results and conclusions of the various experiments on effect of metals on growth and other physiological activities are discussed in Chapters IV and V.
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This thesis deals with the reproductive physiology of the two species of Indian sea mussels, namely the brown mussel perna indica and the green mussel p viridis .The major aspects of the study include ecophysiology of reproduction linking up the animal reproductive cycle of the animals with the ecological conditions of the natural mussel beds, biochemical and histochemical changes associated with reproduction and neurosecretory cycle in synchrony with the reproductive cycle. Some basic studies on gamete morphology and certain aspects of gamete physiology have been taken up. The experimental work deals with the influence of different feeding levels on gamatogenesis and maturation and the effect of ganglia ablation on spawning. The material for the investigation on perna indica were collected from the natural mussel beds at Vizhinjam near Trivandrum and on p.viridic from Elathur, near Calicut. The period of observation extended from October 1981 to December 1982.
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Aquaculture is the dynamic pursuit of production of organisms from water a process analogous to agriculture on land. The field of aquaculture is an emerging bioindustry, based upon the culture and husbandry of economically utilizable aquatic organisms. Of late, there has been a global upsurge for aquaculture, the main reasons for which include the requirement of protein source for the increasing world population, the decision by various world nations to increase the fish yield by developing unutilized or partially utilized water bodies and depletion of natural stock which is evident in recent years due to excessive exploitation .The present study has been taken up on the reproductive physiology of the female grey mullet, M. cephalus. The thesis is presented in seven chapters. In the present study, variations in the major biochemical parameters namely, moisture, proteins, lipids, carbohydrates cholesterol, carotenoid, ash, calcium and iron in four tissues E. muscle, liver, ovary and bloodserum of cephalus have been analysed at different maturity stages.
