965 resultados para Roy adaptation model


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The objective of this study was to perform a cross-cultural adaptation of the Safety Attitudes Questionnaire - Short Form 2006 for Brazil. The instrument was applied in six hospitals in three regions of Brazil. Content, face, and construct validity was performed. Analysis of the instrument's reliability was performed by verifying the items' internal consistency through Cronbach's alpha. The sample was composed of 1301 professionals working in clinical and surgical wards of six hospitals. Confirmatory analysis showed that the model including 41 items was satisfactory. The Portuguese version presented an alpha of 0.89. The item-total correlations among the domains were moderate to strong, except for the domain Stress Recognition. We concluded that the instrument's version adapted to Portuguese and applied in our sample is valid and reliable.

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Despite the great importance of soybeans in Brazil, there have been few applications of soybean crop modeling on Brazilian conditions. Thus, the objective of this study was to use modified crop models to estimate the depleted and potential soybean crop yield in Brazil. The climatic variable data used in the modified simulation of the soybean crop models were temperature, insolation and rainfall. The data set was taken from 33 counties (28 Sao Paulo state counties, and 5 counties from other states that neighbor São Paulo). Among the models, modifications in the estimation of the leaf area of the soybean crop, which includes corrections for the temperature, shading, senescence, CO2, and biomass partition were proposed; also, the methods of input for the model's simulation of the climatic variables were reconsidered. The depleted yields were estimated through a water balance, from which the depletion coefficient was estimated. It can be concluded that the adaptation soybean growth crop model might be used to predict the results of the depleted and potential yield of soybeans, and it can also be used to indicate better locations and periods of tillage.

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Hypoxie ist ein Zustand des Sauerstoffmangels, hervorgerufen durch fehlende Verfügbarkeit von Sauerstoff in der Umgebung eines Organismus oder durch pathologisch bedingte unzureichende Nutzbarkeit des Sauerstoffs von Geweben. Die Sensitivität gegenüber Hypoxie variiert enorm im Tierreich zwischen verschiedenen Phyla und Spezies. Die meisten Säugetiere sind nur unzureichend an niedrige Sauerstoffkonzentrationen angepasst, wohingegen einige unterirdisch lebende Säuger sehr resistent gegen Hypoxiestress sind. Um die molekulare Basis der Hypoxietoleranz zu bestimmen, wurden in der vorliegenden Arbeit Globine untersucht, die potenziell in der Lage sind, als respiratorische Proteine zur Hypoxietoleranz von Tieren beizutragen. Dazu wurde die Expression der Globine in der hypoxieresistenten, in Israel lebenden Blindmaus Spalax ehrenbergi mit der Genexpression in der hypoxiesensitiven Ratte (Rattus norvegicus) verglichen. In der vorliegenden Arbeit wurden die erst vor wenigen Jahren entdeckten Globine Neuroglobin und Cytoglobin untersucht, deren exakte physiologische Rolle noch unklar ist, und mit Daten des viel detaillierter untersuchten Myoglobins verglichen. Beim Vergleich der Expression von Cytoglobin und Neuroglobin in Spalax versus Ratte fällt auf, dass Neuroglobin und Cytoglobin bereits unter normoxischen Bedingungen auf mRNA- und Proteinebene in der Blindmaus um einen Faktor von mindesten 2 bis 3 verstärkt exprimiert werden. Bei Myoglobin (als dem Kontrollgen mit bekannter Funktion) konnte auf mRNA-Ebene eine noch weitaus stärkere Expression in Spalax vs. Ratte gefunden werden. Das übergreifende Phänomen der verstärkten Genexpression von Globinen in Spalax kann im Sinne einer Präadaptation an das unterirdische, häufig hypoxische Leben der Blindmaus interpretiert werden. Einen weiteren Hinweis auf eine besondere, spezialisierte Funktion von Neuroglobin in Spalax geben immunhistochemische Daten, die zeigen, dass Neuroglobin im Gehirn von Spalax im Gegensatz zur Ratte nicht nur in Neuronen, sondern auch in Gliazellen exprimiert wird. Dies impliziert Änderungen des oxidativen Stoffwechsels im Nervensystem der hypoxietoleranten Spezies. Die zellulären Expressionsmuster von Cytoglobin erscheinen hingegen in beiden Säugerspezies weitgehend identisch. Es wurde der Frage nachgegangen, ob und wie experimentell induzierte Hypoxie die Genexpression der Globine verändert. Dabei zeigten sich für Neuroglobin und Cytoglobin unterschiedliche Expressionsmuster. Neuroglobin wird unter diversen Sauerstoffmangelbedingungen sowohl in der Ratte als auch in Spalax auf mRNA- und Proteinebene herunterreguliert. Ein ähnliches Regulationsverhalten wurde auch für Myoglobin beobachtet. Die verminderte Expression von Neuroglobin (und evtl. auch Myoglobin) unter Hypoxie ist mit einer gezielten Verringerung der Sauerstoff-Speicherkapazität in Abwesenheit von O2 zu erklären. Ein weiterer denkbarer Grund könnte auch die allgemeine Tendenz sein, unter Hypoxie aus Energiespargründen den Metabolismus herunter zu regulieren. Cytoglobin, das bei normalen Sauerstoffbedingungen nur im Gehirn von Spalax (nicht jedoch in Herz und Leber) ebenfalls um Faktor 2 bis 3 stärker exprimiert wird als in der Ratte, ist mit einiger Sicherheit ebenfalls von adaptivem Nutzen für die Anpassung von Spalax an niedrige Sauerstoffbedingungen, wenngleich seine Funktion unklar bleibt. Unter Hypoxie wird die Cytoglobin-mRNA sowohl in Spalax als auch in der Ratte hochreguliert. Es konnte in der vorliegenden Arbeit dargelegt werden, dass die Expression von Cygb höchstwahrscheinlich durch den Transkriptionsfaktor Hif-1 gesteuert wird, der die molekulare Hypoxieantwort vieler Tierarten zentral steuert. In der vorliegenden Arbeit wurde ebenfalls die Expression von Ngb und Cygb im Gehirn des Hausschweins (Sus scrofa) untersucht. Diese Spezies diente in der Arbeit als weiterer hypoxiesensitiver Organismus sowie als biomedizinisch relevantes Modell für eine Operation an Säuglingen mit angeborenen Herzkrankheiten. Die Versuche haben gezeigt, dass die Gabe bestimmter Medikamente wie dem Immunsuppressivum FK506 zu einer erhöhten Ngb-Konzentration auf mRNA-Ebene führen kann, was potenziell im Zusammenhang mit beobachteten protektiven Effekten der Medikamentengabe während und nach der Herzoperation steht.

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This paper aims at the development and evaluation of a personalized insulin infusion advisory system (IIAS), able to provide real-time estimations of the appropriate insulin infusion rate for type 1 diabetes mellitus (T1DM) patients using continuous glucose monitors and insulin pumps. The system is based on a nonlinear model-predictive controller (NMPC) that uses a personalized glucose-insulin metabolism model, consisting of two compartmental models and a recurrent neural network. The model takes as input patient's information regarding meal intake, glucose measurements, and insulin infusion rates, and provides glucose predictions. The predictions are fed to the NMPC, in order for the latter to estimate the optimum insulin infusion rates. An algorithm based on fuzzy logic has been developed for the on-line adaptation of the NMPC control parameters. The IIAS has been in silico evaluated using an appropriate simulation environment (UVa T1DM simulator). The IIAS was able to handle various meal profiles, fasting conditions, interpatient variability, intraday variation in physiological parameters, and errors in meal amount estimations.

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Four experiments investigated perception of major and minor thirds whose component tones were sounded simultaneously. Effects akin to categorical perception of speech sounds were found. In the first experiment, musicians demonstrated relatively sharp category boundaries in identification and peaks near the boundary in discrimination tasks of an interval continuum where the bottom note was always an F and the top note varied from A to A flat in seven equal logarithmic steps. Nonmusicians showed these effects only to a small extent. The musicians showed higher than predicted discrimination performance overall, and reaction time increases at category boundaries. In the second experiment, musicians failed to consistently identify or discriminate thirds which varied in absolute pitch, but retained the proper interval ratio. In the last two experiments, using selective adaptation, consistent shifts were found in both identification and discrimination, similar to those found in speech experiments. Manipulations of adapting and test showed that the mechanism underlying the effect appears to be centrally mediated and confined to a frequency-specific level. A multistage model of interval perception, where the first stages deal only with specific pitches may account for the results.

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Altered pressure in the developing left ventricle (LV) results in altered morphology and tissue material properties. Mechanical stress and strain may play a role in the regulating process. This study showed that confocal microscopy, three-dimensional reconstruction, and finite element analysis can provide a detailed model of stress and strain in the trabeculated embryonic heart. The method was used to test the hypothesis that end-diastolic strains are normalized after altered loading of the LV during the stages of trabecular compaction and chamber formation. Stage-29 chick LVs subjected to pressure overload and underload at stage 21 were reconstructed with full trabecular morphology from confocal images and analyzed with finite element techniques. Measured material properties and intraventricular pressures were specified in the models. The results show volume-weighted end-diastolic von Mises stress and strain averaging 50–82% higher in the trabecular tissue than in the compact wall. The volume-weighted-average stresses for the entire LV were 115, 64, and 147Pa in control, underloaded, and overloaded models, while strains were 11, 7, and 4%; thus, neither was normalized in a volume-weighted sense. Localized epicardial strains at mid-longitudinal level were similar among the three groups and to strains measured from high-resolution ultrasound images. Sensitivity analysis showed changes in material properties are more significant than changes in geometry in the overloaded strain adaptation, although resulting stress was similar in both types of adaptation. These results emphasize the importance of appropriate metrics and the role of trabecular tissue in evaluating the evolution of stress and strain in relation to pressure-induced adaptation.

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Research on the physiological adaptation process has found that stress is associated with the rate of cortisol secretion, the main hormone that reflects stress. However, considerable variation among subjects has been reported. Using a sample of older adults (N=46), we tested the hypothesis that cortisol reactivity is composed of (1) a situation-related component representing hypothalamic influence on cortisol secretion observed on three different occasions, and (2) a stable component representing a general trait responsible for cortisol responses observed from occasion to occasion. LISREL VIII was used to test this hypothesis. Results indicated that a homogeneous reliability model was not supported by the data. A congeneric measurement model represented a better fit to the data. Results suggest that subjects have consistent patterns of response during separate experimental occasions. However, results do not suggest a consistent pattern of response over time. The main implication of these results is that salivary cortisol measures are sensitive to experimental stress situations. As such, this noninvasive method may be useful in examining adaptive responses to stress.

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Background The European trout (Salmo trutta species complex) occurs across a very wide altitudinal range from lowland rivers to alpine streams. Historically, the major European river systems contained different, evolutionarily distinct trout lineages, and some of this genetic diversity has persisted in spite of extensive human-mediated translocations. We used AFLP-based genome scans to investigate the extent of potentially adaptive divergence among major drainages and along altitudinal gradients replicated in several rivers. Results The proportion of loci showing evidence of divergent selection was larger between drainages than along altitudinal transects within drainages. This suggests divergent selection is stronger between drainages, or adaptive divergence is constrained by gene flow among populations within drainages, although the latter could not be confirmed at a more local scale. Still, altitudinal divergence occurred and, at approximately 2% of the markers, parallel changes of the AFLP band frequencies with altitude were observed suggesting that altitude may well be an important source of divergent selection within rivers. Conclusions Our results indicate that adaptive genetic divergence is common both between major European river systems and along altitudinal gradients within drainages. Alpine trout appear to be a promising model system to investigate the relative roles of divergent selection and gene flow in promoting or preventing adaptation to climate gradients.

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BACKGROUND: The sensory drive hypothesis predicts that divergent sensory adaptation in different habitats may lead to premating isolation upon secondary contact of populations. Speciation by sensory drive has traditionally been treated as a special case of speciation as a byproduct of adaptation to divergent environments in geographically isolated populations. However, if habitats are heterogeneous, local adaptation in the sensory systems may cause the emergence of reproductively isolated species from a single unstructured population. In polychromatic fishes, visual sensitivity might become adapted to local ambient light regimes and the sensitivity might influence female preferences for male nuptial color. In this paper, we investigate the possibility of speciation by sensory drive as a byproduct of divergent visual adaptation within a single initially unstructured population. We use models based on explicit genetic mechanisms for color vision and nuptial coloration. RESULTS: We show that in simulations in which the adaptive evolution of visual pigments and color perception are explicitly modeled, sensory drive can promote speciation along a short selection gradient within a continuous habitat and population. We assumed that color perception evolves to adapt to the modal light environment that individuals experience and that females prefer to mate with males whose nuptial color they are most sensitive to. In our simulations color perception depends on the absorption spectra of an individual's visual pigments. Speciation occurred most frequently when the steepness of the environmental light gradient was intermediate and dispersal distance of offspring was relatively small. In addition, our results predict that mutations that cause large shifts in the wavelength of peak absorption promote speciation, whereas we did not observe speciation when peak absorption evolved by stepwise mutations with small effect. CONCLUSION: The results suggest that speciation can occur where environmental gradients create divergent selection on sensory modalities that are used in mate choice. Evidence for such gradients exists from several animal groups, and from freshwater and marine fishes in particular. The probability of speciation in a continuous population under such conditions may then critically depend on the genetic architecture of perceptual adaptation and female mate choice.

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We present in this paper several contributions on the collision detection optimization centered on hardware performance. We focus on the broad phase which is the first step of the collision detection process and propose three new ways of parallelization of the well-known Sweep and Prune algorithm. We first developed a multi-core model takes into account the number of available cores. Multi-core architecture enables us to distribute geometric computations with use of multi-threading. Critical writing section and threads idling have been minimized by introducing new data structures for each thread. Programming with directives, like OpenMP, appears to be a good compromise for code portability. We then proposed a new GPU-based algorithm also based on the "Sweep and Prune" that has been adapted to multi-GPU architectures. Our technique is based on a spatial subdivision method used to distribute computations among GPUs. Results show that significant speed-up can be obtained by passing from 1 to 4 GPUs in a large-scale environment.