963 resultados para géis de poliacrilamida


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L'elaborato tratta dell'evoluzione dei sistemi di raccolta dati geografici e mappatura grazie all'utilizzo delle tecnologie informatiche e di come sia cambiato il loro utilizzo nel corso del tempo e l'utenza che ne fa uso. Viene anche trattata in maniera tecnica la struttura che compone uno di questi sistemi per permettere l'interazione via web con una mappa digitale. Si effettuano inoltre ipotesi su possibili sviluppi futuri di tali tecnologie.

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The Nghe-Tinh Soviets of 1930-1931, a rebellion against colonial authority in north-central and central colonial Vietnam, has received extensive analysis by a variety of commentators and scholars, both Vietnamese and not. Most scholars, Vietnam and internationally, settled on some view of immiseration combined with the presence of pro-communist organizers as the motive forces for the rebellion, but a few have favored questions of political dissatisfaction and local empowerment as underlying motivations for revolt. Until recently, examining the rebellion on a gross scale in order to test either theory has proven difficult, with a surfeit of information but no easy way to process it in order to underwrite large-scale analyses. Del Testa is using a historical GIS (geographical information system) analysis, which blends statistics with digitized maps, in order to display correlations between factors, such as wealth, religion, and so on of those who rebelled in order to reexamine the Nghe-Tinh Soviets movement on a grand scale. His presentation will illustrate some initial findings as well as the techniques used.

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Every inclined land surface has a potential for soil and water degradation, the seriousness depends on a multitude of parameters such as slope, soil type, geomorphology, rainfall, land use and natural vegetation cover. In Laos this intensified land use leads to reduced vegetation cover, to increased soil erosion, decreasing yield, and finally is likely to influence the hydrological regime. Against this background the Mekong River Commission (MRC) elaborated a spatial explicit Watershed Classification (WSC) for the Lower Mekong Basin. Based on topographic factors derived from a high-resolution Digital Terrain Model, five watershed classes are calculated, giving indication about the sensitivity to resource degradation by soil erosion. The WSC allows spatial priority setting for watershed management and generally supports informed decision making on reconnaissance level. In the conclusions focus is laid on general considerations when GIS techniques are used for spatial decision support in a development context.

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Geospatial information systems are used to analyze spatial data to provide decision makers with relevant, up-to-date, information. The processing time required for this information is a critical component to response time. Despite advances in algorithms and processing power, we still have many “human-in-the-loop” factors. Given the limited number of geospatial professionals, analysts using their time effectively is very important. The automation and faster humancomputer interactions of common tasks that will not disrupt their workflow or attention is something that is very desirable. The following research describes a novel approach to increase productivity with a wireless, wearable, electroencephalograph (EEG) headset within the geospatial workflow.

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Quantifying belowground dynamics is critical to our understanding of plant and ecosystem function and belowground carbon cycling, yet currently available tools for complex belowground image analyses are insufficient. We introduce novel techniques combining digital image processing tools and geographic information systems (GIS) analysis to permit semi-automated analysis of complex root and soil dynamics. We illustrate methodologies with imagery from microcosms, minirhizotrons, and a rhizotron, in upland and peatland soils. We provide guidelines for correct image capture, a method that automatically stitches together numerous minirhizotron images into one seamless image, and image analysis using image segmentation and classification in SPRING or change analysis in ArcMap. These methods facilitate spatial and temporal root and soil interaction studies, providing a framework to expand a more comprehensive understanding of belowground dynamics.

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Quantitative measures of polygon shapes and orientation are important elements of geospatial analysis. These kinds of measures are particularly valuable in the case of lakes, where shape and orientation patterns can help identifying the geomorphological agents behind lake formation and evolution. However, the lack of built-in tools in commercial geographic information system (GIS) software packages designed for this kind of analysis has meant that many researchers often must rely on tools and workarounds that are not always accurate. Here, an easy-to-use method to measure rectangularity R, ellipticity E, and orientation O is developed. In addition, a new rectangularity vs. ellipticity index, REi, is defined. Following a step-by-step process, it is shown how these measures and index can be easily calculated using a combination of GIS built-in functions. The identification of shapes and estimation of orientations performed by this method is applied to the case study of the geometric and oriented lakes of the Llanos de Moxos, in the Bolivian Amazon, where shape and orientation have been the two most important elements studied to infer possible formation mechanisms. It is shown that, thanks to these new indexes, shape and orientation patterns are unveiled, which would have been hard to identify otherwise.

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Eine vom Centre for Develpment and Environment (CDE) der Universität Bern gestaltete Karte der südsudanesischen Region East Equatoria hat den „New Mapmaker Award 2009“ gewonnen. Der Preis wird gemeinsam von der britischen Kartografiegesellschaft und der amerikanischen National Geographic Society vergeben. Die im Rahmen eines Capacity-Development- Programms für Geoinformationsmanagement entworfene Karte wurde vollumfänglich in ArcMap aufgebaut, ohne Einsatz von Graphiksoftware.