571 resultados para tall
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O culto a Nossa Senhora de Nazaré é uma devoção popular muito antiga em Belém do Pará, quase tão antiga quanto a cidade, pois esse culto se consolidou na mesma época em que se constituiu o município de Belém e o Estado do Pará. A população de devotos cresceu junto com a população dos habitantes da cidade. Tal fato propiciou que essa devoção popular se enraizasse profundamente na cultura paraense, penetrando até a auto-imagem do paraense católico, moldando a sua identidade cultural. A maior expressão desse culto é a grande romaria que os devotos realizam todos os anos no mês de outubro, que é conhecida como Círio de Nazaré e reúne uma média de dois milhões de pessoas, aproximadamente. O Círio de 2002 foi o recorte etnológico dessa pesquisa que disserta sobre as práticas cotidianas dos devotos no seu culto a Nossa Senhora de Nazaré, sobre como a religiosidade popular insere-se no dia-a-dia dos indivíduos, influenciando as representações sociais e recebendo a influência delas também, em um processo dialético.(AU)
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This thesis demonstrates that the use of finite elements need not be confined to space alone, but that they may also be used in the time domain, It is shown that finite element methods may be used successfully to obtain the response of systems to applied forces, including, for example, the accelerations in a tall structure subjected to an earthquake shock. It is further demonstrated that at least one of these methods may be considered to be a practical alternative to more usual methods of solution. A detailed investigation of the accuracy and stability of finite element solutions is included, and methods of applications to both single- and multi-degree of freedom systems are described. Solutions using two different temporal finite elements are compared with those obtained by conventional methods, and a comparison of computation times for the different methods is given. The application of finite element methods to distributed systems is described, using both separate discretizations in space and time, and a combined space-time discretization. The inclusion of both viscous and hysteretic damping is shown to add little to the difficulty of the solution. Temporal finite elements are also seen to be of considerable interest when applied to non-linear systems, both when the system parameters are time-dependent and also when they are functions of displacement. Solutions are given for many different examples, and the computer programs used for the finite element methods are included in an Appendix.
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A Magyar Természetvédők Szövetsége a svájci Pro Natura Természetvédelmi Szervezettel közösen 15 hónapos programot dolgozott ki a biológiai sokféleség magyarországi megőrzését elősegítendően, amelyre a svájci kormánytól kaptunk támogatást. A programon belül képzéseket, konferenciát, svájci tanulmányutat szerveztünk, majd a befejező szakaszban helyi társadalmi kampányokkal igyekszünk a lakosság figyelmét felhívni a probléma súlyosságára, és e program keretében határoztuk el e kiadvány megjelentetését is. A kiadvány célja, hogy felhívja a figyelmet a biológiai sokféleség hanyatlására, annak létünket veszélyeztető következményeire. Tudatosítani szeretnénk a biológiai sokféleség megőrzésének fontosságát és azt, hogy minden egyes ember tehet ezért. Röviden bemutatjuk a hanyatlás megállításával összefüggő nemzetközi és hazai erőfeszítéseket, de a kudarcokat is. Megfogalmazzuk legfontosabb üzeneteinket a követendő irányra vonatkozóan. A hazai és svájci példákon, jó gyakorlatokon keresztül azt is bemutatjuk, hogy a civil szervezetek munkájuk során mit tesznek a természeti értékek megóvásáért, bízva abban, hogy példájuk követésre talál.
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Jelen cikk célja annak mélyrehatóbb vizsgálata, hogy a felsőfokú végzettséggel rendelkező frissdiplomások nagyarányú létszámnövekedése milyen hatással volt a munkaerő-piaci helyzetükre, jelen esetben keresetükre. Homogén-e az egyetemet végzett hallgatók csoportja, vagy elkülöníthetők olyan alcsoportok, amelyben a végzett hallgatók kevesebbet keresnek jobb helyzetben lévő társaiknál? A fentebbi kérdés megválaszolására a Debreceni Egyetem 2007-ben és 2009-ben végzett hallgatóinak Diplomás Pályakövető Rendszeren keresztül nyert adatait használta fel a szerző. A tömegesedés egyik következménye lehet, hogy a felsőfokú végzettséggel rendelkező munkavállaló nem talál a végzettségének megfelelő munkát, és így kénytelen olyan munkakört betölteni, amelynek végzettségigénye alacsonyabb, mint az övé. Az ilyen módon túlképzett munkavállalók keresete alacsonyabb, mint hasonló végzettségű, de megfelelő munkakörben dolgozó társaiké. Ez a vizsgált minta tanúsága szerint a DE végzettjeinek esetében 12-17% körül alakult, ami megfelel a nemzetközi eredményeknek. _________ The main goal of this article to examine the effect of a large increase in the number of university graduates on their labour market position, mainly on their wages. Is the group of graduated students homogenous, or are there any subgroups in which graduates earn less than their counterparts? To answer this question, the author examines the database of the Graduate Students’ Survey which contains data about the students of University of Debrecen who finished their studies in 2007 and 2009. As a result of overeducation, graduates do not find the kind of jobs which require their level of education. These so called overeducated workers earn less than their counterparts. In this case, this wage penalty is between 12%-17%, which is similar to international results.
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A tanulmány célja: bemutatni, hogy a liberális eszmerendszer nem a bukáshoz, hanem egy mérföldkőhöz érkezett a neoliberalizmus korszakának lezárultával. A dolgozat képet ad az eszmerendszer múlt- és jelenbeli dilemmáiról, megoldandó feladatairól és válaszairól. Az Európai Unió pénzügyi és gazdasági válságát politikai válság is kíséri, amelyből egyelőre nem talál kiutat. Az írás bemutatja: mind az Uniónak, mind a liberalizmusnak van jövője, és válságaik kezelésében kölcsönösen segíthetik egymást. Mindhárom eszmerendszer – a konzervatív, a szociáldemokrata és a liberális – újragondolásra szorul. A szerző a liberalizmus újragondolására koncentrál, és bemutatja, hogy az eszmerendszer alapértékeihez való visszatérés, valamint azok gyakorlatban való alkalmazása az Európai Unió válságkezelése szempontjából kulcskérdés.
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Equisetum giganteum L., a giant horsetail, is one of the largest living members of an ancient group of non-flowering plants with a history extending back 377 million years. Its hollow upright stems grow to over 5 m in height. Equisetum giganteum occupies a wide range of habitats in southern South America. Colonies of this horsetail occupy large areas of the Atacama river valleys, including those with sufficiently high groundwater salinity to significantly reduce floristic diversity. The purpose of this research was to study the ecophysiological and biomechanical properties that allow E. giganteum to successfully colonize a range of habitats, varying in salinity and exposure. Stem ecophysiological behavior was measured via steady state porometry (stomatal conductance), thermocouple psychrometry (water potential), chlorophyll fluorescence, and ion specific electrodes (xylem fluid solutes). Stem biomechanical properties were measured via a 3-point bending apparatus and cross sectional imaging. Equisetum giganteum stems exhibit mechanical characteristics of semi-self-supporting plants, requiring mutual support or support of other vegetation when they grow tall. The mean elastic moduli (4.3 Chile, 4.0 Argentina) of E. giganteum in South America is by far the largest measured in any living horsetail. Stomatal behavior of E. giganteum is consistent with that of typical C3 vascular plants, although absolute values of maximum late morning stomatal conductance are very low in comparison to typical plants from mesic habitats. The internode stomata exhibit strong light response. However, the environmental sensitivity of stomatal conductance appeared less in young developing stems, possibly due to higher cuticular conductance. Exclusion of sodium (Na) and preferential accumulation of potassium (K) at the root level appears to be the key mechanism of salinity tolerance in E. giganteum. Overall stomatal conductance and chlorophyll fluorescence were little affected by salinity, ranging from very low levels up to half strength seawater. This suggests a high degree of salinity stress tolerance. The capacity of E. giganteum to adapt to a wide variety of environments in southern South America has allowed it to thrive despite tremendous environmental changes during their long tenure on Earth.
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Extensive portions of the southern Everglades are characterized by series of elongated, raised peat ridges and tree islands oriented parallel to the predominant flow direction, separated by intervening sloughs. Tall herbs or woody species are associated with higher elevations and shorter emergent or floating species are associated with lower elevations. The organic soils in this “Ridge-and-Slough” landscape have been stable over millennia in many locations, but degrade over decades under altered hydrologic conditions. We examined soil, pore water, and leaf phosphorus (P) and nitrogen (N) distributions in six Ridge and Slough communities in Shark Slough, Everglades National Park. We found P enrichment to increase and N to decrease monotonically along a gradient from the most persistently flooded sloughs to rarely flooded ridge environments, with the most dramatic change associated with the transition from marsh to forest. Leaf N:P ratios indicated that the marsh communities were strongly P-limited, while data from several forest types suggested either N-limitation or co-limitation by N and P. Ground water stage in forests exhibited a daytime decrease and partial nighttime recovery during periods of surface exposure. The recovery phase suggested re-supply from adjacent flooded marshes or the underlying aquifer, and a strong hydrologic connection between ridge and slough. We therefore developed a simple steady-state model to explore a mechanism by which a phosphorus conveyor belt driven by both evapotranspiration and the regional flow gradient can contribute to the characteristic Ridge and Slough pattern. The model demonstrated that evapotranspiration sinks at higher elevations can draw in low concentration marsh waters, raising local soil and water P concentrations. Focusing of flow and nutrients at the evapotranspiration zone is not strong enough to overcome the regional gradient entirely, allowing the nutrient to spread downstream and creating an elongated concentration plume in the direction of flow. Our analyses suggest that autogenic processes involving the effects of initially small differences in topography, via their interactions with hydrology and nutrient availability, can produce persistent physiographic patterns in the organic sediments of the Everglades.
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The hydrologic regime of Shark Slough, the most extensive long hydroperiod marsh in Everglades National Park, is largely controlled by the location, volume, and timing of water delivered to it through several control structures from Water Conservation Areas north of the Park. Where natural or anthropogenic barriers to water flow are present, water management practices in this highly regulated system may result in an uneven distribution of water in the marsh, which may impact regional vegetation patterns. In this paper, we use data from 569 sampling locations along five cross-Slough transects to examine regional vegetation distribution, and to test and describe the association of marsh vegetation with several hydrologic and edaphic parameters. Analysis of vegetation:environment relationships yielded estimates of both mean and variance in soil depth, as well as annual hydroperiod, mean water depth, and 30-day maximum water depth within each cover type during the 1990’s. We found that rank abundances of the three major marsh cover types (Tall Sawgrass, Sparse Sawgrass, and Spikerush Marsh) were identical in all portions of Shark Slough, but regional trends in the relative abundance of individual communities were present. Analysis also indicated clear and consistent differences in the hydrologic regime of three marsh cover types, with hydroperiod and water depths increasing in the order Tall Sawgrass , Sparse Sawgrass , Spikerush Marsh. In contrast, soil depth decreased in the same order. Locally, these differences were quite subtle; within a management unit of Shark Slough, mean annual values for the two water depth parameters varied less than 15 cm among types, and hydroperiods varied by 65 days or less. More significantly, regional variation in hydrology equaled or exceeded the variation attributable to cover type within a small area. For instance, estimated hydroperiods for Tall Sawgrass in Northern Shark Slough were longer than for Spikerush Marsh in any of the other regions. Although some of this regional variation may reflect a natural gradient within the Slough, a large proportion is the result of compartmentalization due to current water management practices within the marsh.We conclude that hydroperiod or water depth are the most important influences on vegetation within management units, and attribute larger scale differences in vegetation pattern to the interactions among soil development, hydrology and fire regime in this pivotal portion of Everglades.
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Isotope signatures of mangrove leaves can vary depending on discrimination associated with plant response to environmental stressors defined by gradients of resources (such as water and nutrient limitation) and regulators (such as salinity and sulfide toxicity). We tested the variability of mangrove isotopic signatures (d13C and d15N) across a stress gradient in south Florida, using green leaves from four mangrove species collected at six sites. Mangroves across the landscape studied are stressed by resource and regulator gradients represented by limited phosphorus concentrations combined with high sulfide concentrations, respectively. Foliar d13C ratios exhibited a range from 24.6 to –32.7‰, and multiple regression analysis showed that 46% of the variability in mangrove d13C composition could be explained by the differences in dissolved inorganic nitrogen, soluble reactive phosphorus, and sulfide porewater concentrations. 15N discrimination in mangrove species ranged from –0.1 to 7.7‰, and porewater N, salinity, and leaf N:Pa ratios accounted for 41% of this variability in mangrove leaves. The increase in soil P availability reduced 15N discrimination due to higher N demand. Scrub mangroves (<1.5 m tall) are more water-use efficient, as indicated by higher d13C; and have greater nutrient use efficiency ratios of P than do tall mangroves (5 to 10 m tall) existing in sites with greater soil P concentrations. The high variability of mangrove d13C and d15N across these resource and regulator gradients could be a confounding factor obscuring the linkages between mangrove wetlands and estuarine food webs. These results support the hypothesis that landscape factors may control mangrove structure and function, so that nutrient biogeochemistry and mangrove-based food webs in adjacent estuaries should account for watershed-specific organic inputs.
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Buildings and other infrastructures located in the coastal regions of the US have a higher level of wind vulnerability. Reducing the increasing property losses and causalities associated with severe windstorms has been the central research focus of the wind engineering community. The present wind engineering toolbox consists of building codes and standards, laboratory experiments, and field measurements. The American Society of Civil Engineers (ASCE) 7 standard provides wind loads only for buildings with common shapes. For complex cases it refers to physical modeling. Although this option can be economically viable for large projects, it is not cost-effective for low-rise residential houses. To circumvent these limitations, a numerical approach based on the techniques of Computational Fluid Dynamics (CFD) has been developed. The recent advance in computing technology and significant developments in turbulence modeling is making numerical evaluation of wind effects a more affordable approach. The present study targeted those cases that are not addressed by the standards. These include wind loads on complex roofs for low-rise buildings, aerodynamics of tall buildings, and effects of complex surrounding buildings. Among all the turbulence models investigated, the large eddy simulation (LES) model performed the best in predicting wind loads. The application of a spatially evolving time-dependent wind velocity field with the relevant turbulence structures at the inlet boundaries was found to be essential. All the results were compared and validated with experimental data. The study also revealed CFD's unique flow visualization and aerodynamic data generation capabilities along with a better understanding of the complex three-dimensional aerodynamics of wind-structure interactions. With the proper modeling that realistically represents the actual turbulent atmospheric boundary layer flow, CFD can offer an economical alternative to the existing wind engineering tools. CFD's easy accessibility is expected to transform the practice of structural design for wind, resulting in more wind-resilient and sustainable systems by encouraging optimal aerodynamic and sustainable structural/building design. Thus, this method will help ensure public safety and reduce economic losses due to wind perils.
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Mangrove forests are ecosystems susceptible to changing water levels and temperatures due to climate change as well as perturbations resulting from tropical storms. Numerical models can be used to project mangrove forest responses to regional and global environmental changes, and the reliability of these models depends on surface energy balance closure. However, for tidal ecosystems, the surface energy balance is complex because the energy transport associated with tidal activity remains poorly understood. This study aimed to quantify impacts of tidal flows on energy dynamics within a mangrove ecosystem. To address the research objective, an intensive 10-day study was conducted in a mangrove forest located along the Shark River in the Everglades National Park, FL, USA. Forest–atmosphere turbulent exchanges of energy were quantified with an eddy covariance system installed on a 30-m-tall flux tower. Energy transport associated with tidal activity was calculated based on a coupled mass and energy balance approach. The mass balance included tidal flows and accumulation of water on the forest floor. The energy balance included temporal changes in enthalpy, resulting from tidal flows and temperature changes in the water column. By serving as a net sink or a source of available energy, flood waters reduced the impact of high radiational loads on the mangrove forest. Also, the regression slope of available energy versus sink terms increased from 0.730 to 0.754 and from 0.798 to 0.857, including total enthalpy change in the water column in the surface energy balance for 30-min periods and daily daytime sums, respectively. Results indicated that tidal inundation provides an important mechanism for heat removal and that tidal exchange should be considered in surface energy budgets of coastal ecosystems. Results also demonstrated the importance of including tidal energy advection in mangrove biophysical models that are used for predicting ecosystem response to changing climate and regional freshwater management practices.
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The study was carried out on the main plots of a large grassland biodiversity experiment (the Jena Experiment). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained by bi-annual weeding and mowing. We tracked soil microbial basal respiration (BR; µlO2/g dry soil/h) and biomass carbon (Cmic; µgC/g dry soil) over a time period of 12 years (2003-2014) and examined the role of plant diversity and plant functional group composition for the spatial and temporal stability (calculated as mean/SD) of soil microbial properties (basal respiration and biomass) in bulk-soil. Our results highlight the importance of plant functional group composition for the spatial and temporal stability of soil microbial properties, and hence for microbially-driven ecosystem processes, such as decomposition and element cycling, in temperate semi-natural grassland.
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We explore the thesis that tall structures can be protected by means of seismic metamaterials. Seismic metamaterials can be built as some elements are created over soil layer with different shapes, dimensions, patterns and from different materials. Resonances in these elements are acting as locally resonant metamaterials for Rayleigh surface waves in the geophysics context. Analytically we proved that if we put infinite chain of SDOF resonator over the soil layer as an elastic, homogeneous and isotropic material, vertical component of Rayleigh wave, longitudinal resonance of oscillators will couple with each other, they would create a Rayleigh bandgap frequency, and wave will experience attenuation before it reaches the structure. As it is impossible to use infinite chain of resonators over soil layer, we considered finite number of resonators throughout our simulations. Analytical work is interpreted using finite element simulations that demonstrates the observed attenuation is due to bandgaps when oscillators are arranged at sub-wavelength scale with respect to the incident Rayleigh wave. For wavelength less than 5 meters, the resulting bandgaps are remarkably large and strongly attenuating when impedance of oscillators matches impedance of soil. Since longitudinal resonance of SDOF resonator are proportional to its length inversely, a formed array of resonators that attenuates Rayleigh waves at frequency ≤10 Hz could be designed starting from vertical pillars coupled to the ground. Optimum number of vertical pillars and their interval spacing called effective area of resonators are investigated. For 10 pillars with effective area of 1 meter and resonance frequency of 4.9 Hz, bandgap frequency causes attenuation and a sinusoidal impulsive force illustrate wave steering down phenomena. Simulation results proved analytical findings of this work.