988 resultados para extreme hydro meteorological phenomena


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This sub-collection is the result of an investigation into the mechanism of organic fouling in membrane filtration processes. In this experiment, poly(vinylidene fluoride) (PVDF) membranes were used to filter two types of organic foulants, protein and yeast with a concentration of 50mg/l and 20 mg/l, respectively, from suspension in a dead-end filtration cell. These model foulants were stained with fluorescent dyes before filtration. This dataset contains a stack of images of the fouling layer on the PVDF membrane surface captured by a confocal laser scanning microscope (CLSM) and its associated acquisition software. This dataset would be useful to researchers who are investigating the membrane organic fouling mechanism so that new membrane materials and new anti-fouling surface treatment technologies can be developed for water and wastewater industry in the future.

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This sub-collection is the result of an investigation into the mechanism of organic fouling in membrane filtration processes. In this experiment, poly(vinylidene fluoride) (PVDF) membranes were used to filter two types of organic foulants, protein and sodium alginate with a concentration of 50mg/l and 40 mg/l, respectively, from suspension in a dead-end filtration cell. These model foulants were stained with fluorescent dyes before filtration. This dataset contains a stack of images of the fouling layer on the PVDF membrane surface captured by a confocal laser scanning microscope (CLSM) and its associated acquisition software. This dataset would be useful to researchers who are investigating the membrane organic fouling mechanism so that new membrane materials and new anti-fouling surface treatment technologies can be developed for water and wastewater industry in the future.

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This sub-collection is the result of an investigation into the mechanism of organic fouling in membrane filtration processes. In this experiment, poly(vinylidene fluoride) (PVDF) membranes were used to filter three types of organic foulants, yeast, protein and sodium alginate with a concentration of 50mg/l, 40mg/l and 20 mg/l, respectively, from suspension in a dead-end filtration cell. These model foulants were stained with fluorescent dyes before filtration. This dataset contains a stack of images of the fouling layer on the PVDF membrane surface captured by a confocal laser scanning microscope (CLSM) and its associated acquisition software. This dataset would be useful to researchers who are investigating the membrane organic fouling mechanism so that new membrane materials and new anti-fouling surface treatment technologies can be developed for water and wastewater industry in the future .

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Fishes are often subjected to seasonal and spatial patchiness of food sources. We tested how risk-taking behaviour in the six-lined trumpeter, an estuarine seagrass resident fish, changed with hunger level in a laboratory experiment. When repeatedly offered a risky source of food, well-fed fish did not approach it and all fish survived over a one-month trial. In contrast, fish deprived of all food boldly first approached the risky food source after only a few days without food in some cases, or after many days in other cases, and then continued to approach risky food each time it was presented. Larger individuals were more bold (and had longer starvation endurance) than smaller ones, and after statistically controlling for these size effects, there were consistent individual differences in the propensity to take risks (i.e. boldness). These results show that food- and individual-dependent boldness will together affect vulnerability to predators and influence predation rates when resources become scarce.

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Glycogen plays a major role in supporting the energy demands of skeletal muscles during high intensity exercise. Despite its importance, the amount of glycogen stored in skeletal muscles is so small that a large fraction of it can be depleted in response to a single bout of high intensity exercise. For this reason, it is generally recommended to ingest food after exercise to replenish rapidly muscle glycogen stores, otherwise one's ability to engage in high intensity activity might be compromised. But what if food is not available? It is now well established that, even in the absence of food intake, skeletal muscles have the capacity to replenish some of their glycogen at the expense of endogenous carbon sources such as lactate. This is facilitated, in part, by the transient dephosphorylation-mediated activation of glycogen synthase and inhibition of glycogen phosphorylase. There is also evidence that muscle glycogen synthesis occurs even under conditions conducive to an increased oxidation of lactate post-exercise, such as during active recovery from high intensity exercise. Indeed, although during active recovery glycogen resynthesis is impaired in skeletal muscle as a whole because of increased lactate oxidation, muscle glycogen stores are replenished in Type IIa and IIb fibers while being broken down in Type I fibers of active muscles. This unique ability of Type II fibers to replenish their glycogen stores during exercise should not come as a surprise given the advantages in maintaining adequate muscle glycogen stores in those fibers that play a major role in fight or flight responses.

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In my research, I examined body phenomena in psychosis by exploring onset, triggering events and stabilisation in psychosis. I concluded that body disturbances can be important indicators for the onset of psychosis and, that these disturbances provide a framework for better understanding the recovery from psychosis, particularly in schizophrenia.

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Surviving prolonged fasting implies closely regulated alterations in fuel provisioning to meet metabolic requirements, while preserving homeostasis. Little is known, however, of the endocrine regulations governing such metabolic adaptations in naturally fasting free-ranging animals. The hormonal responses to natural prolonged fasting and how they correlate to the metabolic adaptations observed, were investigated in subantarctic fur seal (Arctocephalus tropicalis) pups, which, because of the intermittent pattern of maternal attendance, repeatedly endure exceptionally long fasting episodes throughout their development (1–3 mo). Phase I fasting was characterized by a dramatic decrease in plasma insulin, glucagon, leptin, and total L-thyroxine (T4) associated with reductions in mass-specific resting metabolic rate (RMR), plasma triglycerides, glycerol, and urea-to-creatine ratio, while nonesterified fatty acids (NEFA) and β-OHB increased. In contrast, the metabolic steady-state of phase II fasting reached within 6 days was associated with minimal concentrations of insulin, glucagon, and leptin; unchanged cortisol and triiodothyronine (T3); and moderately increased T4. The early fall in insulin and leptin may mediate the shift to the strategy of energy conservation, protein sparing, and primary reliance on body lipids observed in response to the cessation of feeding. In contrast to the typical mammalian starvation response, nonelevated cortisol and minimal glucagon levels may contribute to body protein preservation and downregulation of catabolic pathways, in general. Furthermore, thyroid hormones may be involved in a process of energy conservation, independent of pups' nutritional state. These original hormonal settings might reflect an adaptation to the otariid repeated fasting pattern and emphasize the crucial importance of a tight physiological control over metabolism to survive extreme energetic constraints.

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Obsessive-compulsive disorder (OCD) is one of the most disabling and highly prevalent anxiety disorders. Cognitive models implicate maladaptive beliefs such as inflated sense of responsibility, perfectionism, importance/control of thoughts in the maintenance of the disorder, but little research has investigated factors that may lead to these beliefs. This paper investigated whether a dysfunctional attachment system may be one such factor, by examining how adult attachment orientations (dimensions of attachment anxiety and avoidance) relate to OCDrelated cognitions, OCD symptoms, and depression. Using structural equation modeling in a student sample (N = 446), the present study found evidence for a mediational model, where attachment dimensions contributed to OCD symptoms via OCD-related cognitions, while controlling for depression. The paper discusses the association between adult attachment orientations and OCD symptoms in the context of current cognitive-behavioral theories of OCD.

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Drawing on neuropsychological and cognitive-behavioral approaches to Obsessive-Compulsive Disorder (OCD), the present study examined the association between memory performance, cognitive confidence, and OCD phenomena. Forty-six analogue participants completed a series of self-report questionnaires and neuropsychological tasks before and after a manipulation of confidence in memory It was found that cognitive confidence predicts OCD symptoms over and above the influence of depressive symptoms and other OCD-related beliefs. Participants reported higher levels of cognitive confidence following positive feedback on the manipulation task. However, changes in cognitive confidence following the manipulation task were not reflected in neuropsychological performance. Implications for theory and treatment are discussed.

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For many species, there is broad-scale dispersal of juvenile stages and/or long-distance migration of individuals and hence the processes that drive these various wide-ranging movements have important life-history consequences. Sea turtles are one of these paradigmatic long-distance travellers, with hatchlings thought to be dispersed by ocean currents and adults often shuttling between distant breeding and foraging grounds. Here, we use multi-disciplinary oceanographic, atmospheric and genetic mixed stock analyses to show that juvenile turtles are encountered ‘downstream’ at sites predicted by currents. However, in some cases, unusual occurrences of juveniles are more readily explained by storm events and we show that juvenile turtles may be displaced thousands of kilometres from their expected dispersal based on prevailing ocean currents. As such, storms may be a route by which unexpected areas are encountered by juveniles which may in turn shape adult migrations. Increased stormy weather predicted under climate change scenarios suggests an increasing role of storms in dispersal of sea turtles and other marine groups with life-stages near the ocean surface.

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Over the course of the last decade, infrared (IR) and particularly thermal IR imaging based face recognition has emerged as a promising complement to conventional, visible spectrum based approaches which continue to struggle when applied in practice. While inherently insensitive to visible spectrum illumination changes, IR data introduces specific challenges of its own, most notably sensitivity to factors which affect facial heat emission patterns, e.g. emotional state, ambient temperature, and alcohol intake. In addition, facial expression and pose changes are more difficult to correct in IR images because they are less rich in high frequency detail which is an important cue for fitting any deformable model. In this paper we describe a novel method which addresses these major challenges. Specifically, when comparing two thermal IR images of faces, we mutually normalize their poses and facial expressions by using an active appearance model (AAM) to generate synthetic images of the two faces with a neutral facial expression and in the same view (the average of the two input views). This is achieved by piecewise affine warping which follows AAM fitting. A major contribution of our work is the use of an AAM ensemble in which each AAM is specialized to a particular range of poses and a particular region of the thermal IR face space. Combined with the contributions from our previous work which addressed the problem of reliable AAM fitting in the thermal IR spectrum, and the development of a person-specific representation robust to transient changes in the pattern of facial temperature emissions, the proposed ensemble framework accurately matches faces across the full range of yaw from frontal to profile, even in the presence of scale variation (e.g. due to the varying distance of a subject from the camera). The effectiveness of the proposed approach is demonstrated on the largest public database of thermal IR images of faces and a newly acquired data set of thermal IR motion videos. Our approach achieved perfect recognition performance on both data sets, significantly outperforming the current state of the art methods even when they are trained with multiple images spanning a range of head views.

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Our aim in this paper is to robustly match frontal faces in the presence of extreme illumination changes, using only a single training image per person and a single probe image. In the illumination conditions we consider, which include those with the dominant light source placed behind and to the side of the user, directly above and pointing downwards or indeed below and pointing upwards, this is a most challenging problem. The presence of sharp cast shadows, large poorly illuminated regions of the face, quantum and quantization noise and other nuisance effects, makes it difficult to extract a sufficiently discriminative yet robust representation. We introduce a representation which is based on image gradient directions near robust edges which correspond to characteristic facial features. Robust edges are extracted using a cascade of processing steps, each of which seeks to harness further discriminative information or normalize for a particular source of extra-personal appearance variability. The proposed representation was evaluated on the extremely difficult YaleB data set. Unlike most of the previous work we include all available illuminations, perform training using a single image per person and match these also to a single probe image. In this challenging evaluation setup, the proposed gradient edge map achieved 0.8% error rate, demonstrating a nearly perfect receiver-operator characteristic curve behaviour. This is by far the best performance achieved in this setup reported in the literature, the best performing methods previously proposed attaining error rates of approximately 6–7%.