876 resultados para PROPIEDADES SUPERFICIE DEL SUELO


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Conflictes socioterritorials i participació pública en la gestió de l'aigua de la conca del riu Muga (Alt Empordà) és un treball que incideix sobre la conflictivitat en la gestió dels rius mediterranis i prospecta en la participació pública -activa i vinculant- per a la resolució de conflictes i la planificació i gestió dels recursos hídrics. En concret, s'ha intentat donar resposta a cinc objectius: Objectius del marc teòric - Comprovar l'existència de dos discursos antagònics (radicalment oposats) en l'esfera social, científica i de gestió dels rius que generen conflicte i que són insostenibles per a una gestió integral dels recursos fluvials: el discurs antropocèntric i el discurs ecocèntric. Matèria d'estudi: L'excepcionalisme humà i l'ecologia profunda en la societat; Les disciplines de la regulació de l'aigua i de l'ecologia fluvial en la ciència; El contracte antropocèntric i el balanç ecocèntric en la gestió; El discurs ambiental (el riu antròpic i ecosistemàtic). - Valorar si les estratègies de participació pública (que involucren als agents socials) gaudeixen -respecte els processos de decisió unilaterals (siguin autoritàries o arbitràries)- de més garanties per corregir i prevenir conflictes desconstructius relacionats amb l'aigua i els recursos fluvials. Matèria d'estudi: Definició de conflicte en positiu; L'estratègia de cooperació i consens en la Resolució Alternativa de Disputes (Alternative Dispute Resolution) i 13 casos resolts de conflictes per l'aigua a l'Oest dels Estats Units; Bases d'un pla de gestió integral, adaptatiu i participatiu i el cas del San Joaquin River Management Plan (Califòrnia, Estats Units). Objectius del marc pràctic. Conca del riu Muga (Alt Empordà) - Contextualitzar la diversificació i intensificació dels usos de l'aigua dins un procés de canvi dels usos del sòl, particularment accelerat a partir de la dècada de 1960 i objecte de problemàtiques socioterritorials d'ençà de la dècada de 1980. Cartografia i matriu de canvi dels usos del sòl de la conca anys 1993 i 1957. Matèria d'estudi: Cartografia i estadística dels usos del sòl de la conca del riu Muga (49 municipis altempordanesos, 1.050 km2), anys 1957 i 1993. Retrospectiva dels espais forestals, d'aigua, conreats i urbanitzats. - Identificar i descriure les tensions i conflictes en l'ús de l'aigua, així com les característiques de les solucions adoptades en el període 1980-2000. Constatar si determinades solucions estructurals han esdevingut problemàtiques a mig o llarg termini, i estimar la probabilitat de conflictes futurs. Matèria d'estudi: 50 incidents problemàtics en abastament d'aigua (26 tensions i 24 conflictes) i 53 mesures per fer-hi front (12 d'adaptació de la demanda i 41 d'adaptació de l'oferta d'aigua) entre els anys 1980 i 2000, i diferenciant dues unitats territorials de la conca (la Muga interior i la plana de la Muga). - Caracteritzar quins són els temes en matèria d'aigua que no disposen de consens entre els agents socioeconòmics, tècnics i polítics locals reunits en les sessions de discussió del projecte MUGA. Determinar si les estratègies participatives poden prosperar perquè són factibles i idònies. Matèria d'estudi: Projecte MUGA: Gestión del recurso agua con participación de agentes. Estudio para la cuenca del río Muga (Girona), 2000-2003 - UAB i UdG; La dissensió d'opinions dels 30 participants a les 4 sessions de discussió entorn l'ús i gestió de l'aigua de la conca de la Muga; 6 temes de conflicte, 14 subtemes i 31 punts de discussió, 9 dels quals punts calents de conflicte (destructius i indicadors de punts de disfunció en la gestió de l'aigua de la conca).

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The methodology is focused on the use of digital air photos to monitor changes in land covers and to study its dynamics and its patterns in the last 50 years. The dissertation also take into account the relationship between open habitats patterns/dynamics versus biodiversity persistence, increase risk of fire, land ownership and management. Therefore Geographic Information System (GIS) is a very interesting mapping tool that enables geographic or spatial data capture, storage, retrieval, manipulation, analysis and modeling. Finally this research develop a heuristic model to create sites using suitability maps and a reserve design model to select the most optimum sites in order to increase landscape heterogeneity at the less cost.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Incluye bibliografía

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Incluye Bibliografía

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Incluye Bibliografía

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Dental tooth bleaching is a conservative option for the treatment of tooth stains. It is based on the use of hydrogen peroxide as an active agent. Despite its effectiveness to lighten tooth colour, there is concern regarding its use due to the effects it could have over enamel surface. There is scarce evidence on the subject and contradictions exist between different authors. The aim of this study was to compare enamel surface micromorphology after bleaching teeth with different concentrations of hydrogen peroxide solutions. Method: 50 healthy bovine incisors sectioned horizontally at the cemento-enamel junction were prepared. Contents of pulp chamber and tooth surfaces were cleaned. The buccal surface of each tooth was divided vertically, assigning one half to the control group (CG) and the other randomly to: Group 1: 25 samples treated with 15% hydrogen peroxide with nitrogen doped titanium dioxide. Group 2: 25 samples treated with 35% hydrogen peroxide. Square samples (2x2 mm.) were obtained and observed by SEM (magnification of 5.000x and 10.000x). Results: All treated groups showed longitudinal depressions on the surface and increased surface roughness. Conclusions: Tooth bleaching with hydrogen peroxide produces subclinical alterations over bovine enamel surface. 15% hydrogen peroxide bleaching agent produced less micromorphology alteration over bovine enamel surface than the 35% hydrogen peroxide agent.

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The demand for cosmetic dentistry, including teeth whitening, has increased in recent years. The home teeth whitening and in-office, are widely used in dental practice. The mechanism by which it works is by oxidation of the chromogenic existing tooth structure. This is an effective and minimally invasive procedure that achieves tooth lighten the color, however, may cause alterations in the enamel surface, such as a dental permeability increase. Another effect caused by this procedure is tooth sensitivity, being the most common side effect, up to 65% of individuals have had a secondary effect at least once during treatment. This sensitivity and gingival irritation caused by bleaching may vary depending on the patient and used bleaching product

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All trees with diameter at breast height dbh >= 10.0 cm were stem-mapped in a "terra firme" tropical rainforest in the Brazilian Amazon, at the EMBRAPA Experimental Site, Manaus, Brazil. Specifically, the relationships of tree species with soil properties were determined by using canonical correspondence analyses based on nine soil variables and 68 tree species. From the canonical correspondence analyses, the species were grouped into two groups: one where species occur mainly in sandy sites, presenting low organic matter content; and another one where species occur mainly in dry and clayey sites. Hence, we used Ripley's K function to analyze the distribution of species in 32 plots ranging from 2,500 m(2) to 20,000 m(2) to determine whether each group presents some spatial aggregation as a soil variations result. Significant spatial aggregation for the two groups was found only at over 10,000 m(2) sampling units, particularly for those species found in clayey soils and drier environments, where the sampling units investigated seemed to meet the species requirements. Soil variables, mediated by topographic positions had influenced species spatial aggregation, mainly in an intermediate to large distances varied range (>= 20 m). Based on our findings, we conclude that environmental heterogeneity and 10,000 m(2) minimum sample unit sizes should be considered in forest dynamic studies in order to understand the spatial processes structuring the "terra firme" tropical rainforest in Brazilian Amazon.

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The enrichment of an organic compound with biofertilizers of microorganisms (solubilizing phosphorus bacteria, BSF) can improve the properties of phosphate fertilizers applied to soils to increase nutrient availability. The experimental design was randomized complete blocks with a factorial 4x2 +1 arrangement of treatments: 1) four sources of phosphorus: phosphate rock, natural phosphate, triple superphosphate (TSP) and Cuban phosphate rock; 2) two sources of bio-fertilizer prepared from filter cake (cane waste) enriched with microorganisms and no enrichment; 3) and an absolute control (no filter cake or fertilizer); repeated three times. Data was analyzed with ANOVA and treatment means were compared using Tukey (p <= 0.05). Assessments of available P (Bray-2 and Oniani methodology) and the quantification of total and solubilizing bacteria and fungi in the soil were performed 30, 60 and 90 d after starting the experiment. After 60 d, the population of BSF was lower in the control (p <= 0.05) and the content of P (Bray-2) was higher for SFT (p <= 0.01). The application of the bio-fertilizer increased the P content compared to the control. At 90 d P (Bray-2) increased with the SFT treatment, which also increased (p P in the soil at 60 and 90 d regardless of the presence of microorganism-enriched bio-fertilizer. The use of filter cake enriched with microorganisms associated with different sources of P, and applied to the soil with a high content of P, did not change the soil populations of total and solubilizing bacteria and fungi in the short term. TSP promoted the highest levels of P in the soil, irrespective of the presence of the organic compound enriched with P solubilizing microorganisms.

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The increasing expansion of agricultural activities, without considering the potential and limitations of soils is a potential source of environmental degradation. Thus, the present study assessed the variation of use and occupation in 49 years, between 1962 and 2011 scenarios of watershed of São Caetano - Botucatu (SP). geoprocessing techniques were used in this study. In a Geographic Information System (GIS) - IDRISI – it was integrated information from IBGE digital cards, scale 1:50,000, plus aerial photographs (1962) and satellite images LANDSAT - 5 (2011). In the study area, we can view the progress of the urban area, which in 1962 was not present in the watershed. In 2011, the urban area occupied 21.37% of the total area. Even with this breakthrough occurring in the period of 49 years, there was an increase in the area of natural vegetation, which once occupied only 12.33% of the area (1962), and in 2011 represents 25% of the total area of the watershed, showing an increase in awareness on the importance of preserving nature. Thus, we can conclude that the analysis tools based on GIS enabled us to analyze variations in space and time and to propose alternatives to the correct use and occupation of land.

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The knowledge of the soil occupation as for his nature, location, occurrence form, changes happened in certain periods, they are valuable for the programming of activities that you seek to the development agricultural, economical and social of the area. This work aimed at to identify and to quantify the soil occupation of Stream Petiço Watershed - Botucatu (SP), through the Geographical Information System IDRISI and data of sensor Landsat 5 TM of 09/06/97 and 23/08/2013. For the analysis of the results it was verified that the eucalyptus culture, due to existence of great reforestation companies in the watershed, together with the native forests they are predominant in the study area, the remaining of the area is occupied by pastures and soil prepared for the planting of agricultural cultures.