968 resultados para Slopes


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In this paper, the use of differential evolution ( DE), a global search technique inspired by evolutionary theory, to find the parameters that are required to achieve optimum dynamic response of parallel operation of inverters with no interconnection among the controllers is proposed. Basically, in order to reach such a goal, the system is modeled in a certain way that the slopes of P-omega and Q-V curves are the parameters to be tuned. Such parameters, when properly tuned, result in system's eigenvalues located in positions that assure the system's stability and oscillation-free dynamic response with minimum settling time. This paper describes the modeling approach and provides an overview of the motivation for the optimization and a description of the DE technique. Simulation and experimental results are also presented, and they show the viability of the proposed method.

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The rapid growth of the Brazilian cities in the latest years has brought a series of problems regarding housing policies and, therefore, the provision of dwellings for the low-income class people. Following the pattern of other capital cities, Natal has repeated the pattern of urbanization practiced in the country, which concentrates the low-income class inhabitants in specific zones of the city known as peripheries or even in a dwelling place for less-favored classes such as Felipe Camarão, which is one of ten boroughs belonging to the western administrative zone, a region which has historically received less attention from the public administrators towards infrastructure investments. Based on those aspects, the general objective of this work is to investigate which main social-environmental alterations have resulted from the processes of urbanization and field occupation in that area. The specific objectives are concerned with verifying 1) the process of urbanization and the process of dividing urban soil from the 1960s; 2) the current configuration of the public spaces in the borough; 3) the process of the deprivation of the original landscape characteristics of Environmental Protection Zones; 4) the dynamics of land occupation which are predominant in dune areas; 5) the dynamics of land occupation which are predominant in mangrove areas; 6) and the destruction of green covering on the land with its consequent alteration of the local floristic pattern. The methodology consisted of in-loco visits; the application of questionnaires as community research; a survey of bibliography published by the organisms and institutions in charge of carrying out the city hall s environmental and housing policies; and descriptive statistics of the collected data. Concerning the pattern of occupation which is predominant in the borough, the treatment of space dispensed by the local dwellers has culminated in the emergence and consolidation of environmental alterations which are clearly different from common occurrence in both the building area represented by housing complexes and in the green areas represented by dunes and mangroves. The data show that there was the predominance of the irregular land occupation process over the official housing policy during the population settlement which contributed with a series of frequent and foreseeable problems in the dynamics of urbanization of poverty such as invasions and appropriations of land parcels, the beginning of irregular arrangement of streets, the formation of villages and slums, which are full of self-constructed housing units, and the occupation and degradation of susceptibly fragile environmental areas such as the dune slopes and the mangroves

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Environmental changes and their consequences on the global level have challenged the different fields of study to integrate towards effective solutions to minimize and /or equate the negative impacts of these changes in different types of environments. In this context, the Environmental Perception has been a widely used and relevant in studies that consider the relationship between the environment and human actions, by allowing analysis of perceptions, attitudes and values, key influencers of topophilia that resonates in conservation tool. Allied to Environmental Perception, Integrated Analysis of the Landscape is relevant because it allows to analyze in a systematic way the geographical space where all its elements are interrelated in a way that supports needed to understand the complex physical and human environment of a given environment. In this perspective, we have studied the João do Vale Serrano Complex, located in semiarid of Rio Grande do Norte state, which features a set of landscapes with different faces, which are being replaced by various economic activities and disordered population growth, with consequent exploitation the potential of natural resources. This thesis main goal was to combine the Environmental Perception of rural communities to the of Serrano Complex Landscape Analysis as additional criteria for the definition of Priority Areas for Conservation. The perception data were collected through direct observation, questioning, interviews and application forms to 240 people (100 % of occupied households in the mountain community) during the months of february and august 2011, with theoretical and methodological basis Environmental Perception. Integrated Landscape Analysis was performed by GTP (Geosystem - Territory - Landscape) method, using the Geographic Information System (GIS), using the technique of GIS for mapping the landscape. The results showed that respondents have a sense of topophilia by where they live, hold a vast knowledge of the natural resources in this Serrano Complex, and responded positively regarding the choice of an exclusive area for conservation. The Integrated Analysis of Landscape possible to identify the different forms of existing uses and occupations in Serrano Complex, have caused significant changes in space, especially on the plateau where vegetation was virtually replaced by human dwellings and cashew plantations. Through the maps of slope and environmental vulnerability was identified that areas with high slopes (gullies) are limiting factor for occupation by communities and therefore relevant and amenable to conservation, including by being Permanent Preservation Areas. These results, together, made possible to define a map of Priority Areas for Conservation in Serrano Complex, with three priority categories: low, medium and high. Therefore, the use of these additional criteria are relevant for the definition /designation of Priority Areas for Conservation

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A morpho-structural analysis was performed in the uplifted siliciclastic deposits of the Serra do Martins Formation along the Portalegre, Martins and Santana plateaux, in the southeastern and central regions of Rio Grande do Norte State. Due to the lack of biostratigraphic records, this formation has a disputable age.The adopted approach was based on the analysis of the drainage patterns and in the recognition of topographic surfaces and regional structures, subjected to neotectonic deformation and rejuvenation the present stress field. These events are recorded in the lineament arrays and as anomalous features of the landscape, such as the uplifted plateaux.The morpho-sculptural evolution of the studied blocks is expressed as erosive and accumulative processes. The former ones include erosional scarpments, cuestas and amphitheaters as the most characteristic features, while debris slopes represent acumulative examples. Such elements attest to the recent disequilibrium of the plateaux, and the absence of well developed alluvium terraces suggest an accelerated uplift process. The directions of the linear features observed in remote sensing products evidence the control of the basement structural trends, inherited from the pre-Cenozoic evolution. The NNE-SSW direction controls the main erosional features of the plateaux, while the N-S direction is a major drainage control, being also recognized in the Potiguar Basin. An E-W trend occurs as a less developed direction, reflecting either a system of mesozoic basic dykes or precambrian brittle structures. As regards to the drainage arrays, an arborescent, varying to a roughly N-S rectangular pattern, was identified in the Portalegre-Martins block. The Santana plateau displays rectilinear (northern border) and dendritic arborescent (southern border) patterns. In the sedimentary cover, the drainage pattern varies from rectangular to angular, reflecting inheritance from the crystaline basement. The most significative directions, N, NE and NW, mark the erosional fronts of the plateaux. Drainage anomalies, characterized by elbows or paralell confluencies, reinforce the arguments mentioned above. The data sets evidence the relationships between endogenous (lithology, structures) and exogenous features as the main controls of terrain dissecation, associated to vertical (epirogenesis) movements and horizontal tectonics. A final discussion addresses the relationships of the Serra do Martins Formation with the sedimentary record of Potiguar Basin, trying to establish chronostratigraphic links with the main evolutionary steps of this part of the Borborema Province, and possible mechanisms involved in the uplift of the plateaux and other stratigraphic units in the region

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The effects of castration on alpha(1)-adrenoceptors in rat vas deferens were investigated by determining the actions of selective antagonists against the contractions induced by noradrenaline. The results obtained in vas deferens from control rats suggest participation of alpha(1A)-adrenoceptors as judged by the pA(2) values for prazosin (9.6), benoxathian (9.5), 2(2,6-dimethoxyphenoxyethyl) amino-methyl-1,4-benzodioxone hydrochloride) (WB 4101) (9.6), phentolamine (8.4), 8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4.5] decane-7,9-dionedihydrochloride (BMY 7378) (6.7) and by the insensitivity to chloroethylclonidine (100 mu M, 45 min). In vas deferens from castrated rats, WE 4101 and spiperone showed slopes lower than 1.0 in the Schild plots, suggesting participation of multiple receptors. In these organs, noradrenaline contractions were partially inhibited by chloroethylclonidine (100 mu M, 45 min), indicating participation of alpha(1B)-adrenoceptors. After chloroethylclonidine treatment, WE 4101 showed a slope not different from 1.0 in the Schild plot, resulting in a pA(2) of 9.4, which indicates an interaction with alpha(1A)-adrenoceptors. It is suggested that castration modifies the functional alpha(1)-adrenoceptors subtypes in rat vas deferens. (C) 1998 Elsevier B.V. B.V. All rights reserved.

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The contractions of the rat vas deferens in response to noradrenaline are mediated through alpha(1A)-adrenoceptors. We observed participation of alpha(1B)-adrenoceptors in these contractions after castration. We now investigated the time course of this plasticity and the effects of testosterone by determining the actions of competitive antagonists on noradrenaline-induced contractions after 7, 14, 21 and 30 days of castration. BMY 7378 (8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4.5]decane-7,9-dione dihydrochloride) antagonised noradrenaline-induced contractions in control and castrated rats with low pA(2) values (congruent to 6.8). In control vas deferens, WB 4101 (2-(2,6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane hydrochloride) had a slope in the Schild plot no different from 1.0, while slopes lower than 1.0 ( approximate to 0.6) were observed for vas deferens from castrated rats. Chloroethylclonidine was ineffective in the control vas while it inhibited noradrenaline-induced contractions in vasa from castrated rats and converted the complex antagonism by WB 4101 into simple competitive antagonism. Treatment of castrated rats with testosterone prevented the effects of castration. The results suggest that alpha(1B)-adrenoceptors are detectable in vas deferens from at least the 7th through the 30th day after castration and that testosterone prevents this plasticity. (C) 2003 Elsevier B.V. B.V. All rights reserved.

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

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1 the actions of the alpha(1)-adrenoceptor antagonist indoramin have been examined against the contractions induced by noradrenaline in the rat vas deferens and aorta taking into account a putative neuronal uptake blocking activity of this antagonist which could. result in self-cancelling actions.2 Indoramin behaved as a simple competitive antagonist of the contractions induced by noradrenaline in the vas deferens and aorta yielding pA(2) values of 7.38 +/- 0.05 (slope = 0.98 +/- 0.03) and 6.78 +/- 0.14 (slope = 1.08 +/- 0.06), respectively.3 When the experiments were repeated in the presence of cocaine (6 mu M) the potency (pA(2)) of indoramin in antagonizing the contractions of the vas deferens to noradrenaline was increased to 8.72 +/- 0.07 (slope = 1.10 +/- 0.05) while its potency remained unchanged in the aorta (pA(2) = 6.69 +/- 0.12; slope = 1.04 +/- 0.05).4 In denervated vas deferens, indoramin antagonized the contractions to noradrenaline with a potency similar to that found in the presence of cocaine (8.79 +/- 0.07; slope = 1.09 +/- 0.06).5 It is suggested that indoramin blocks alpha(1)-adrenoceptors and neuronal uptake in rat vas deferens resulting in Schild plots with slopes not different from unity even in the absence of selective inhibition of neuronal uptake. As a major consequence of this double mechanism of action, the pA(2) values for this antagonist are underestimated when calculated in situations where the neuronal uptake is active, yielding spurious pK(B) values.

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This paper summarizes floristic and phytossociology data of 11, out of 14 plots of 1 ha, allocated along an altitudinal gradient in the Serra do Mar, Silo Paulo, Brazil. The study was conducted at Serra do Mar State Park and the plots start at the sea level (10 m - plot of Restinga Forest that occurs at Praia da Fazenda, Picinguaba, municipality of Ubatuba) up to 1100 m above sea level (the Montane Ombrophilous Dense occurs alongside the Itamambuca Trail, municipality of Silo Luis do Paraitinga). The Restinga Forest occurs in Pleistocenic Coastal Plain where the soil is classified as a sandy Quartzipsamment (Quartzenic Neosol), while along the slopes of the Serra do Mar, the Ombrophylus Dense Forest grows on the top of a pre-Cambrian crystalline basement with granitic rocks, where the soil is a sandy-loam Dystrophic Inceptisol (Cambisol/Latosol). In all 14 plots soils are acidic (pH 3 - 4), chemically poor, with high dilution of nutrients and high saturation of aluminum. In the Restinga and at the foot of the slope the climate is Tropical/Subtropical Humid (Af/Cfa), with no dry season, an average annual rainfall over 2,200 mm and an average annual temperature of 22 degrees C. Towards the top of the Serra do Mar there is a gradual cooling along the slope, but there is no reduction in rainfall, so at 1,100 m above sea level the climate is classified as Humid Subtropical (Cfa/Cfb), with no dry season and an average annual temperature of 17 degrees C. It is important to remark that, almost daily, from 400 m above sea level up to the top of slopes the mountains are covered by a dense fog. In the 14 plots 21,733 individuals with DBH >= 4.8 cm, including trees, palms and ferns, were marked, measured and sampled. The average number of individuals sampled in each plot was 1264 ind.ha(-1)(+/- 218 SE 95%). Within the parameters considered trees prevailed (71% in the Montane ODF to 90% in the Restinga Forest), followed by palms (10% in the RF and 25% in the Montane Ombrophilous Dense Forest/ODF) and ferns (0% % in the RF and 4% in the Montane ODF). Regarding these proportions the Exploited Lowlands ODF differs from the others with only 1.8% of palm trees and striking 10% of ferns. The forest canopy is irregular with heights ranging from 7 to 9 m, rarely emergent trees reach 18 m, and due to this irregularity of the canopy the amount of light that gets through sets conditions for the development of hundreds of epiphytic species. Aside from Montana ODF, where the number of dead trees was more than 5% of individuals sampled, in the other phytophysiognomies this value was below 2.5%. In the 11 plots where the floristic study was conducted we found 562 species in 195 genera and 68 families. Only seven species - Euterpe edulis Mart. (Arecaceae), Calyptranthes lucida Mart. ex DC. and Marlierea tomentosa Cambess (both Myrtaceae), Guapira opposita (Veil.) Reitz (Nyctaginaceae), Cupania oblongifolia Mart. (Sapindaceae), Cecropia glaziovii Snethl. and Coussapoa microcarpa (Schott) Rizzini (both Urticaceae) - occurred from Restinga to Montane ODF, while 12 other species did not occur only in the Restinga Forest. Families with the greatest number of species are Myrtaceae (133 spp), Fabaceae (47 spp), Rubiaceae (49) and Lauraceae (49) throughout the gradient and Monimiaceae (21) specifically in portions Montane ODF. Only in the F plot, where logging has occurred between 1950 and 1985, the abundance of palm trees has been replaced by Cyatheaceae. The study shows a peak of diversity and richness, Shannon-Weiner index (H') ranging from 3.96 to 4.48 nats.ind(-1), in the intermediate altitudes (300 to 400 m) along the slope. Several explanations for this result are raised here, including the fact that these elevations are within the limits expansions and retractions of the different phytophysiognomies of the Atlantic ODF due to climate fluctuations during the Pleistocene. The results presented in this paper demonstrate the extraordinary richness of tree species of the Atlantic Rainforest from the northeastern coast of the State of São Paulo, reinforcing the importance of its conservation throughout the altitudinal gradient. The richness of this forest justifies a long term commitment to study its dynamics and functioning through permanent plots, and monitor the impacts of climate change in this vegetation.

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

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In the Atlantic Montane Rain Forest of south-eastern Brazil, a field study was carried out to describe the forest disturbance regime, analyse canopy gap composition and evaluate the influence of habitat parameters on gap tree species composition. We characterized canopy gaps considering the group of variables as follows: area, type and number of tree/branch falls, topographic position, soil coverage and surrounding canopy trees. Gap composition was assessed at species level by measuring all individuals inside gaps higher than one meter. Mean gap area of the 42 canopy gaps analysed was 71.9 +/- 9.0 m(2) (mean +/- SE). Out of the studied gaps, 35.7% were created by uprooted and by snapped trees, 16.7% by dead-standing trees and 11.9% by the fall of large branches. The disturbance regime was characterized by gap openings predominantly smaller than 150 m(2) and by spatial patterning related to topography. Ridges had smaller gaps and higher proportions of gaps created by branch falls; slopes had bigger gaps generally created by uprooting events. The more abundant and frequent species were shade tolerant and the more species-rich families found inside gaps did not differ from the forest as a whole. Pioneer species were rare and restricted to medium and large size classes. The Indicator Species Analysis and the Canonical Correspondence Analysis indicated gap area, topography and the percentage of soil cover by the genera Calathea and Ctenanthe were the predominant variables correlated with woody species distribution. So, topography emerged as an important issue not only to the gap disturbance regime, but also to gap colonization. In respect to the influence of gap processes on the Atlantic Montane Rain Forest regeneration, our results support the view that canopy gap events may not be working as promoters of community wide floristic shifts.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The aims of this study were (a) to assess the ability of the rating of perceived exertion (RPE) to predict performance (i.e. number of vertical jumps performed to a fixed jump height) of an intermittent vertical jump exercise, and (b) to determine the ability of RPE to describe the physiological demand of such exercise. Eight healthy men performed intermittent vertical jumps with rest periods of 4, 5, and 6s until fatigue. Heart rate and RPE were recorded every five jumps throughout the sessions. The number of vertical jumps performed was also recorded. Random coefficient growth curve analysis identified relationships between the number of vertical jumps and both RPE and heart rate for which there were similar slopes. In addition, there were no differences between individual slopes and the mean slope for either RPE or heart rate. Moreover, RPE and number of jumps were highly correlated throughout all sessions (r=0.97-0.99; P0.001), as were RPE and heart rate (r=0.93-0.97; P0.001). The findings suggest that RPE can both predict the performance of intermittent vertical jump exercise and describe the physiological demands of such exercise.

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The aim of this study was to evaluate the EMG activity of lumbar multifidus (MU), longissimus thoracis (LT) and iliocostalis (IC) muscles during an upper limb resistance exercise (biceps curl). Ten healthy males performed maximal voluntary isometric contraction (MVC) of the trunk extensors, after this, the biceps curl exercise was executed at 25%, 30%, 35% and 40% one repetition maximum during 1 min, with 10 min rest between them. EMG root mean square (RMS) and median frequency (MFreq) were calculated for each lifting and lowering of the bar during the exercise bouts, to calculate slopes and intercepts. The results showed increases in the RMS and decreases in the MFreq slopes. RMS slopes were no different between muscles, indicating similar fatigue process along the exercise irrespective of the load level. MU and LT presented higher RMS irrespective of the load level, which can be related to the specific function during the standing position. on the other hand, IC and MU presented higher MFreq intercepts compared to LT, demonstrating possible differences in the muscle fiber conduction velocity of these muscles. These findings suggest that trunk muscles are differently activate during upper limb exercises, and the fatigue process affects the lumbar muscles similarly. (C) 2008 Elsevier Ltd. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)