892 resultados para Topographic categorization


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RESUMO - A frequente insuficiência de informação e até, eventualmente, a presença de elementos cientificamente pouco robustos (ou mesmo hipotéticos) no procedimento de obtenção dos resultados finais (scores) com os diversos métodos de avaliação do risco, julga-se determinar a obtenção de distintos resultados no mesmo posto de trabalho e que interessam analisar. O presente estudo foi efectuado numa empresa da indústria automóvel e pretendeu contribuir para a efectividade do processo de avaliação do risco destas lesões em meio industrial. Utilizaram-se como ponto de partida as classificações de risco em postos de trabalho onde a aplicação do método OCRA — base do projecto de norma Europeu prEN 1005-5 para a estimativa do risco de LMEMSLT (Lesões Musculoesqueléticas do Membro Superior Ligadas ao Trabalho) — identificou níveis de risco moderados e/ou elevados (score OCRA ≥ 16,5). Assim nos postos de trabalho (n = 71) registou-se em vídeo a actividade de trabalho. Analisaram-se os principais factores de risco (postura, força, repetitividade e exposição a vibrações) com uma amostragem de segundo em segundo e aplicaram-se dois métodos: 1) RULA (McAtamney; Corlett, 1993); 2) SI (Moore; Garg, 1995). Dos resultados globais da aplicação dos métodos identificam- se discrepâncias evidentes: o método SI classificou 41 postos de risco elevado e o método RULA classificou apenas 26 postos de risco. Destaque para as divergências entre os postos classificados de risco elevado como, por exemplo: de entre os 41 postos com scores de risco da aplicação do método SI apenas se encontram 12 postos classificados de risco pelo método RULA. Os resultados permitem evidenciar validades preditivas diversas para os factores de risco analisados: 1) situações de aplicação de força (SI = 0,80; RULA = 0,66); 2) presença de posturas extremas (SI = 0,68; RULA = 0,48); 3) repetitividade (SI = 0,35; RULA = 0,43). Conclui-se pela divergência de resultados dos métodos SI e RULA aplicados nos mesmos postos de trabalho que tal situação alerta para a pertinência da utilização de um filtro que permita a identificação dos factores de risco presentes em cada posto de trabalho e que, por consequência, oriente a selecção do método mais indicado ou ainda, em oposição, do método contra-indicado. Este trabalho, como um contributo para uma efectiva identificação e avaliação do risco de LMEMSLT, conduz, no limite, à necessidade de elaboração de uma «grelha» das «grelhas» e de informação mais precisa sobre os métodos e sua aplicação, permitindo, desse modo, uma mais efectiva gestão do risco destas lesões.

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Relationships between accuracy and speed of decision-making, or speed-accuracy tradeoffs (SAT), have been extensively studied. However, the range of SAT observed varies widely across studies for reasons that are unclear. Several explanations have been proposed, including motivation or incentive for speed vs. accuracy, species and modality but none of these hypotheses has been directly tested. An alternative explanation is that the different degrees of SAT are related to the nature of the task being performed. Here, we addressed this problem by comparing SAT in two odor-guided decision tasks that were identical except for the nature of the task uncertainty: an odor mixture categorization task, where the distinguishing information is reduced by making the stimuli more similar to each other; and an odor identification task in which the information is reduced by lowering the intensity over a range of three log steps. (...)

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Dissertação de Mestrado em Políticas de Desenvolvimento de Recursos Humanos

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The long term goal of this research is to develop a program able to produce an automatic segmentation and categorization of textual sequences into discourse types. In this preliminary contribution, we present the construction of an algorithm which takes a segmented text as input and attempts to produce a categorization of sequences, such as narrative, argumentative, descriptive and so on. Also, this work aims at investigating a possible convergence between the typological approach developed in particular in the field of text and discourse analysis in French by Adam (2008) and Bronckart (1997) and unsupervised statistical learning.

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Locating new wind farms is of crucial importance for energy policies of the next decade. To select the new location, an accurate picture of the wind fields is necessary. However, characterizing wind fields is a difficult task, since the phenomenon is highly nonlinear and related to complex topographical features. In this paper, we propose both a nonparametric model to estimate wind speed at different time instants and a procedure to discover underrepresented topographic conditions, where new measuring stations could be added. Compared to space filling techniques, this last approach privileges optimization of the output space, thus locating new potential measuring sites through the uncertainty of the model itself.

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Normal visual perception requires differentiating foreground from background objects. Differences in physical attributes sometimes determine this relationship. Often such differences must instead be inferred, as when two objects or their parts have the same luminance. Modal completion refers to such perceptual "filling-in" of object borders that are accompanied by concurrent brightness enhancement, in turn termed illusory contours (ICs). Amodal completion is filling-in without concurrent brightness enhancement. Presently there are controversies regarding whether both completion processes use a common neural mechanism and whether perceptual filling-in is a bottom-up, feedforward process initiating at the lowest levels of the cortical visual pathway or commences at higher-tier regions. We previously examined modal completion (Murray et al., 2002) and provided evidence that the earliest modal IC sensitivity occurs within higher-tier object recognition areas of the lateral occipital complex (LOC). We further proposed that previous observations of IC sensitivity in lower-tier regions likely reflect feedback modulation from the LOC. The present study tested these proposals, examining the commonality between modal and amodal completion mechanisms with high-density electrical mapping, spatiotemporal topographic analyses, and the local autoregressive average distributed linear inverse source estimation. A common initial mechanism for both types of completion processes (140 msec) that manifested as a modulation in response strength within higher-tier visual areas, including the LOC and parietal structures, is demonstrated, whereas differential mechanisms were evident only at a subsequent time period (240 msec), with amodal completion relying on continued strong responses in these structures.

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Parvalbumin-immunoreactive interneurons are surrounded by perineuronal nets, containing molecules of the extracellular matrix (e.g. tenascin-R). Furthermore, they seem to have a special cytoskeleton composed of, among others, ankyrinR and beta Rspectrin. In the present developmental study we showed that the intracellular markers parvalbumin, ankyrinR and beta Rspectrin as well as Vicia Villosa agglutinin, an extracellular marker for perineuronal nets, appeared in the second postnatal week. In the third postnatal week, ankyrinR and beta R spectrin were present in the parvalbumin-positive interneurons. Tenascin-R appeared in a similar topographic distribution as the intracellular markers. The adult pattern was established upon the end of the fourth postnatal week. Our results indicate that cytoskeletal maturity maybe a prerequisite for the organization of perineuronal nets of extracellular matrix.

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Salmonid populations of many rivers are rapidly declining. One possible explanation is that habitat fragmentation increases genetic drift and reduces the populations' potential to adapt to changing environmental conditions. We measured the genetic and eco-morphological diversity of brown trout (Salmo trutta) in a Swiss stream system, using multivariate statistics and Bayesian clustering. We found large genetic and phenotypic variation within only 40 km of stream length. Eighty-eight percent of all pairwise F(ST) comparisons and 50% of the population comparisons in body shape were significant. High success rates of population assignment tests confirmed the distinctiveness of populations in both genotype and phenotype. Spatial analysis revealed that divergence increased with waterway distance, the number of weirs, and stretches of poor habitat between sampling locations, but effects of isolation-by-distance and habitat fragmentation could not be fully disentangled. Stocking intensity varied between streams but did not appear to erode genetic diversity within populations. A lack of association between phenotypic and genetic divergence points to a role of local adaptation or phenotypically plastic responses to habitat heterogeneity. Indeed, body shape could be largely explained by topographic stream slope, and variation in overall phenotype matched the flow regimes of the respective habitats.

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Accurate perception of the order of occurrence of sensory information is critical for the building up of coherent representations of the external world from ongoing flows of sensory inputs. While some psychophysical evidence reports that performance on temporal perception can improve, the underlying neural mechanisms remain unresolved. Using electrical neuroimaging analyses of auditory evoked potentials (AEPs), we identified the brain dynamics and mechanism supporting improvements in auditory temporal order judgment (TOJ) during the course of the first vs. latter half of the experiment. Training-induced changes in brain activity were first evident 43-76 ms post stimulus onset and followed from topographic, rather than pure strength, AEP modulations. Improvements in auditory TOJ accuracy thus followed from changes in the configuration of the underlying brain networks during the initial stages of sensory processing. Source estimations revealed an increase in the lateralization of initially bilateral posterior sylvian region (PSR) responses at the beginning of the experiment to left-hemisphere dominance at its end. Further supporting the critical role of left and right PSR in auditory TOJ proficiency, as the experiment progressed, responses in the left and right PSR went from being correlated to un-correlated. These collective findings provide insights on the neurophysiologic mechanism and plasticity of temporal processing of sounds and are consistent with models based on spike timing dependent plasticity.

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Identifying adaptive genetic variation is a challenging task, in particular in non-model species for which genomic information is still limited or absent. Here, we studied distribution patterns of amplified fragment length polymorphisms (AFLPs) in response to environmental variation, in 13 alpine plant species consistently sampled across the entire European Alps. Multiple linear regressions were performed between AFLP allele frequencies per site as dependent variables and two categories of independent variables, namely Moran's eigenvector map MEM variables (to account for spatial and unaccounted environmental variation, and historical demographic processes) and environmental variables. These associations allowed the identification of 153 loci of ecological relevance. Univariate regressions between allele frequency and each environmental factor further showed that loci of ecological relevance were mainly correlated with MEM variables. We found that precipitation and temperature were the best environmental predictors, whereas topographic factors were rarely involved in environmental associations. Climatic factors, subject to rapid variation as a result of the current global warming, are known to strongly influence the fate of alpine plants. Our study shows, for the first time for a large number of species, that the same environmental variables are drivers of plant adaptation at the scale of a whole biome, here the European Alps.

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A regional geochemical reconnaissance by bottom stream sediment sampling, has delineated an area of high metal content in the north central sector of the North Creek Watershed. Development of a geochemical model, relating to the relative chemical concentrations derived from the chemical analyses of bottom sediments, suspended sediments, stream waters and well waters collected from the north central sector, was designed to discover the source of the anomaly. Samples of each type of material were analysed by the A.R.L. Direct Reading Multi-element Emission Spectrograph Q.A. 137 for elements: Na, K, Ca, Sr, Si, As, Pb, Zn, Cd, Ni, Ti, Ag, Mo, Be, Fe, AI, Mn, Cu, Cr, P and Y. Anomalous results led to the discovery of a spring, the waters of which carried high concentrations of Zn, Cd, Pb, As, Ni, Ti, Ag, Sr and Si. In addition, the spring waters had high concentrations of Na, Ca, Mg, 504 , alkalinity, N03' and low concentrations of K, Cl and NH3. Increased specific conductivity (up to 2500 ~mho/cm.) was noted in the spring waters as well as increased calculated total dissolved solids (up to 2047 mg/l) and increased ionic strength (up to 0.06). On the other hand, decreases were noted in water temperature (8°C), pH (pH 7.2) and Eh (+.154 volts). Piezometer nests were installed in the anomalous north central sector of the watershed. In accordance with the slope of the piezometric surface from wells cased down to the till/bedrock interface, groundwater flow is directed from the recharge area (northwest of the anomaly) towards the artesian spring via the highly fractured dolostone aquifer of the Upper Eramosa Member. The bedrock aquifer is confined by the overlying Halton till and the underlying Lower Eramosa Member (Vinemount Shale). The oxidation of sphalerite and galena and the dissolution of gypsum, celestite, calcite, and dolomite within the Eramosa Member, contributed its highly, dissolved constituents to the circulating groundwaters, the age of which is greater than 20 years as determined by tritium dating. Groundwater is assumed to flow along the Vinemount Shale and discharge as an artesian spring where the shale unit becomes discontinuous. The anomaly is located on a topographic low where bedrock is close to the surface. Thermodynamic evaluation of the major ion speciation from the anomalous spring and surface waters, showed gypsum to be supersaturated in these spring waters. Downstream from the spring, the loss of carbon dioxide from the spring waters resulted in the supersaturation with respect to calcite, aragonite, magnesite and dolomite. This corresponded with increases in Eh (+.304 volts) and pH (pH 8.5) in the anomalous surface waters. In conclusion, the interaction of groundwaters within the highly, mineralized carbonate source (Eramosa Member) resulted in the characteristic Ca*Mg*HC03*S04 spring water at the anomalous site, which appeared to be the principle effect upon controlling the anomalous surface water chemistry.

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Previous studies have shown that adults and 8-year-olds process faces using norm-based coding and that prolonged exposure to one kind of facial distortion (e.g., compressed features) temporarily shifts the prototype, a process called adaptation, making similarly distorted faces appear more attractive (Anzures et aI., 2009; Valentine, 1999; Webster & MacLin, 1999). Aftereffects provide evidence that our prototype is continually updated by experience. When adults are adapted to two face categories (e.g., Caucasian and Chinese; male and female) distorted in opposing directions (e.g., expanded vs. compressed), their attractiveness ratings shift in opposite directions (Bestelmeyer et aI., 2008; Jaquet et aI., 2007), indicating that adults have dissociable prototypes for some face categories. I created a novel meth04 to investigate whether children show opposing aftereffects. Children and adults were adapted to Caucasian and Chinese faces distorted in opposite directions in the context of a computerized storybook. When testing adults to validate my method, I discovered that opposing aftereffects are contingent on how participants categorize faces and that this categorization is dependent on the context in which adapting stimuli are presented. Opposing aftereffects for Caucasian and Chinese faces were evident when the salience of race was exaggerated by presenting faces in the context of racially segregated birthday parties; expanded faces selected as most normal more often for the race of face that was expanded during adaptation than for the race of face that was compressed. However, opposing aftereffects were not evident when members of the two groups were presented engaging in cooperative social interactions at a racially integrated birthday party. Using the storybook that emphasized face race I 11 provide the first evidence that 8-year-olds demonstrate opposing aftereffects for two face categories defined by race, both when judging face normality and when rating attractiveness.

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The purpose of the present study was first to determine what influences international students' perceptions of prejudice, and secondly to examine how perceptions of prejudice would affect international students' group identification. Variables such as stigma vulnerability and contact which have been previously linked with perceptions of prejudice and intergroup relations were re-examined (Berryman-Fink, 2006; Gilbert, 1998; Nesdale & Todd, 2000), while variables classically linked to prejudicial attitudes such as right-wing authoritarianism and openness to experience were explored in relation to perceptions of prejudice. Furthermore, the study examined how perceptions of prejudice might affect the students' identification choices, by testing two opposing models. The first model was based on the motivational nature of social identity theory (Tajfel & Turner, 1986) while the second model was based on the cognitive nature of self-categorization theory/ rejection-identification model (Turner, Hogg, Oakes, Reicher, & Wetherell, 1987; Schmitt, Spears, & Branscombe,2003). It was hypothesized that stigma vulnerability, right-wing authoritarianism, openness to experience and contact would predict both personal and group perceptions of prejudice. It was also hypothesized that perceptions of prejudice would predict group identification. If the self-categorizationlrejection-identification model was supported, international students would identify with the international students. If the social mobility strategy was supported, international students would identify with the university students group. Participants were 98 international students who filled out questionnaires on the Brock University Psychology Department Website. The first hypothesis was supported. The combination of stigma vulnerability, right-wing authoritarianism, openness to experience and contact predicted both personal and group prejudice perceptions of international students. Furthermore, the analyses supported the self-categorizationlrejectionidentification model. International identification was predicted by the combination of personal and group prejudice perceptions of international students.

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Marshall McLuhan's "global village", and his theories on communications and technology, in conjunction with Patrick McGoohan's television series The Prisoner (ATV, 1967-1968) are explored in this thesis. The Prisoner, brainchild of McGoohan, is about the abduction and confinement of a British government agent imprisoned within the impenetrable boundaries of a benign but totalitarian city -state called "The Village". The purpose of his abduction and imprisonment is for the extraction of information regarding his resignation as a government spy. Marshall McLuhan originally popularized the phrase "the global village" in The Gutenberg Galaxy: The Making o/the Topographic Man (1962), asserting that, "The new electronic interdependence recreates the world in the image of a global village" (p. 31). This thesis argues that valid parallels exist between McGoohan's conception of "village", as manifested in The Prisoner, and McLuhan's global village. The comprehensive methodological stratagem for this thesis includes Marshall McLuhan's "mosaic" approach, Mikhail Bakhtin's concept ofthe "chronotope", as well as a Foucauldian genealogicallhistorical discourse analysis. In the process of deconstructing McLuhan's texts and The Prisoner as products of the 1960s, an historical "constellation" (to use Walter Benjamin's concept) of the same present has been executed. By employing this synthesized methodology, conjunctions have been made between McLuhan's theories and the series' main themes of bureaucracy as dictatorship, the perversion of science and technology, freedom as illusion, and the individual in opposition to the collective. A thorough investigation of the global village and The Prisoner will determine whether or not Marshall McLuhan and/or Patrick McGoohan visualize the village as an enslaving technological reality.

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Psychopathy is associated with well-known characteristics such as a lack of empathy and impulsive behaviour, but it has also been associated with impaired recognition of emotional facial expressions. The use of event-related potentials (ERPs) to examine this phenomenon could shed light on the specific time course and neural activation associated with emotion recognition processes as they relate to psychopathic traits. In the current study we examined the PI , N170, and vertex positive potential (VPP) ERP components and behavioural performance with respect to scores on the Self-Report Psychopathy (SRP-III) questionnaire. Thirty undergraduates completed two tasks, the first of which required the recognition and categorization of affective face stimuli under varying presentation conditions. Happy, angry or fearful faces were presented under with attention directed to the mouth, nose or eye region and varied stimulus exposure duration (30, 75, or 150 ms). We found that behavioural performance to be unrelated to psychopathic personality traits in all conditions, but there was a trend for the Nl70 to peak later in response to fearful and happy facial expressions for individuals high in psychopathic traits. However, the amplitude of the VPP was significantly negatively associated with psychopathic traits, but only in response to stimuli presented under a nose-level fixation. Finally, psychopathic traits were found to be associated with longer N170 latencies in response to stimuli presented under the 30 ms exposure duration. In the second task, participants were required to inhibit processing of irrelevant affective and scrambled face distractors while categorizing unrelated word stimuli as living or nonliving. Psychopathic traits were hypothesized to be positively associated with behavioural performance, as it was proposed that individuals high in psychopathic traits would be less likely to automatically attend to task-irrelevant affective distractors, facilitating word categorization. Thus, decreased interference would be reflected in smaller N170 components, indicating less neural activity associated with processing of distractor faces. We found that overall performance decreased in the presence of angry and fearful distractor faces as psychopathic traits increased. In addition, the amplitude of the N170 decreased and the latency increased in response to affective distractor faces for individuals with higher levels of psychopathic traits. Although we failed to find the predicted behavioural deficit in emotion recognition in Task 1 and facilitation effect in Task 2, the findings of increased N170 and VPP latencies in response to emotional faces are consistent wi th the proposition that abnormal emotion recognition processes may in fact be inherent to psychopathy as a continuous personality trait.