El Índice de Humedad Topográfica (TWI) puede ayudar a determinar la distribución espacial de la riqueza de especies de plantas, el pH del suelo, el nivel del agua subterránea y la humedad del suelo ...de una cuenca hidrográfica. En el presente trabajo, se estima el TWI para la cuenca La Mina en la costa ecuatoriana evaluando la influencia de diferentes métodos de cálculo y de la resolución del insumo sobre los resultados. Se procede a partir de modelos digitales de elevación (DEMs) con herramientas computacionales como Quantum GIS (QGIS), y el modelo hidrológico TOPMODEL. Se concluye que el contenido y resolución de la información de un DEM tienen una influencia en los resultados de TWI.
The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. A correct version of Table 3 is available here: thumbnail Download: * PPT ...PowerPoint slide * PNG larger image * TIFF original image Figures Citation: Lin D, Lai J, Muller-Landau HC, Mi X, Ma K (2013) Correction: Topographic Variation in Aboveground Biomass in a Subtropical Evergreen Broad-Leaved Forest in China.
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Accurate estimate of ocean surface currents is both a challenging issue and a growing end‐users requirement. In this paper ocean currents are calculated at two levels (surface and 15 m depth) as the ...sum of the geostrophic and Ekman components. First, a new, global, 14° Mean Dynamic Topography, called the CNES‐CLS13 MDT, has been calculated and is now available for use by the oceanographic community. By exploiting information from surface drifters and Argo floats, the new MDT resolves spatial scales beyond the resolution permitted by the recent Gravity and Ocean Circulation Experiment (GOCE) geoid models (125 km). Associated mean geostrophic speeds in strong currents are increased by 200% on average compared to GOCE‐based mean currents. In addition, for the first time, a two‐level, monthly, empirical Ekman model that samples a spiral‐like behavior is estimated. We show that combining both pieces of information leads to improved ocean currents compared to other existing observed products.
Key Points
New global Mean Dynamic Topography from GOCE, altimetry, and in situ dataNew two‐level Ekman model from the joint analysis of Argo floats and SVP driftersNew ocean currents by combining geostrophy and Ekman at surface and 15m depth
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In the River Plate area after the Declaration of Independence in 1816, knowledge of the territory became a key tool in the generation of a new order. Land was considered the main source of wealth, ...and the creation of the Department of Topography put in motion the work of specialists in the measurement and representation of the Province of Buenos Aires. The intention is to reflect on graphic representation as a tool for the appropriation, control and projection of space. Para tener una idea del valor de la suscripción, hemos comparado este valor con el de los sueldos anuales de los miembros del DT que aparece en una comunicación de 2 de abril de 1834, donde se especifica que el sueldo del cargo más alto del primer oficial del DT -que en ese momento era Saturnino Salas- era de 1.200 pesos anuales, y el de los delineadores, de 700.
Resolving changes in topography through time using accurate high‐resolution digital elevation models (DEMs) is key to understanding active volcanic processes. For the first time in a volcanic ...environment, we utilize very high‐resolution tri‐stereo optical imagery acquired by the Pleiades‐1 satellite constellation and generate a 1 m resolution DEM of Fogo Volcano, Cape Verde—the most active volcano in the Eastern Atlantic region. Point cloud density is increased by a factor of 6.5 compared to conventional stereo imagery, and the number of 1 m2 pixels with no height measurements is reduced by 43%. We use the DEM to quantify topographic changes associated with the 2014–2015 eruption at Fogo. Height differences between the posteruptive Pleiades‐1 DEM and the preeruptive topography from TanDEM‐X give a lava flow volume of 45.83 ± 0.02 × 106 m3, emplaced over an area of 4.8 km2 at a mean rate of 6.8 m3 s−1.
Key Points
Tri‐stereo photogrammetry at Fogo increases point cloud density by a factor of 6.5 and reduces area with no height measurements by 43%
Estimated accuracy of heights in generated tri‐stereo Pleiades‐1 DEM is <0.51 m
Lava flow volume and mean output rate of 2014–2015 Fogo eruption are 45.83 ± 0.02 × 106 m3 and 6.8 m3 s−1
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Whether or not background secondary craters dominate populations of small impact craters on terrestrial bodies is a half‐century controversy. It has been suggested that small craters on some ...planetary bodies are dominated by background secondary craters based partly on the steepened slope of crater size‐frequency distribution (CSFD) toward small diameters, such as the less than ~1 km diameter crater population on the lunar mare. Here we show that topography degradation enlarges craters and increases CSFD slopes with time. When topography degradation is taken into account, for various‐aged crater populations, the observed steep CSFD at small diameters is uniformly consistent with an originally shallower CSFD, whose slope is undifferentiated from the CSFD slope estimated from near‐Earth objects and terrestrial bolides. The results show that the effect of topography degradation on CSFD is important in dating planetary surfaces, and the steepening of CSFD slopes is not necessarily caused by secondary cratering, but rather a natural consequence of topography degradation.
Key Points
CSFD evolves with time due to the fact that topography degradation enlarges crater diameters
Steep CSFD at lunar small crater diameters can be caused by topography degradation and does not necessarily require secondary craters
Degradation is important in establishing the true production function and could cause crater density uncertainties up to ~2.5 times
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Insight, na Psicologia Experimental, indica, tradicionalmente, a resolução súbita e espontânea de um determinado problema. O presente estudo verificou a ocorrência de resolução súbita em ...macacos-prego (Sapajus spp.) a partir do treino de habilidades pré-requisitos de uma tarefa. Adicionalmente o estudo avaliou se a manipulação do local de treino altera a topografia de solução do problema. Dois sujeitos foram treinados a: a) encaixar objetos e b) pescar objetos fora do alcance utilizando uma ferramenta. O treino das duas habilidades se deu de forma independente e em diferentes contextos. A tarefa final consistiiu em pescar um alimento fora do alcance encaixando um par de ferramentas nunca antes manuseado. Os dois sujeitos resolveram a tarefa, entretanto, nenhum apresentou um desempenho tipicamente de insight, na medida em que as resoluções foram pouco fluidas, com pausas entre suas etapas, e aparentemente sem direcionamento. Discute-se o papel do treino das habilidades pré-requisitos em ambientes diferenciados como um fator que dificulta a resolução da tarefa.
Mapping and Empire Reinhartz, Dennis; Saxon, Gerald D
2005, 20050101
eBook
From the sixteenth through the mid-nineteenth centuries, Spain, then Mexico, and finally the United States took ownership of the land from the Gulf Coast of Texas and Mexico to the Pacific Coast of ...Alta and Baja California—today's American Southwest. Each country faced the challenge of holding on to territory that was poorly known and sparsely settled, and each responded by sending out military mapping expeditions to set boundaries and chart topographical features. All three countries recognized that turning terra incognita into clearly delineated political units was a key step in empire building, as vital to their national interest as the activities of the missionaries, civilian officials, settlers, and adventurers who followed in the footsteps of the soldier-engineers. With essays by eight leading historians, this book offers the most current and comprehensive overview of the processes by which Spanish, Mexican, and U.S. soldier-engineers mapped the southwestern frontier, as well as the local and even geopolitical consequences of their mapping. Three essays focus on Spanish efforts to map the Gulf and Pacific Coasts, to chart the inland Southwest, and to define and defend its boundaries against English, French, Russian, and American incursions. Subsequent essays investigate the role that mapping played both in Mexico's attempts to maintain control of its northern territory and in the United States' push to expand its political boundary to the Pacific Ocean. The concluding essay draws connections between mapping in the Southwest and the geopolitical history of the Americas and Europe.
To organize and filter visual information across visual space, the visual system draws upon receptive fields, spatial attention, and perceptual grouping. Receptive fields refer to the portion of ...visual space altering a neuron's response when visually stimulated. They represent the building blocks of topographic maps in visual cortex, where receptive fields of neighboring neurons correspond to neighboring portions in the retina and visual space. This retinotopy preserves the spatial arrangement of a visual scene. However, receptive fields are not hard-wired spatial filters. Specifically, research on perceptual grouping and spatial attention showed that receptive field properties depend on the observer's perceptual-cognitive state. Spatial attention allows us to prioritize information processing at particular locations in visual space, and evidence suggests receptive fields shift towards attended locations. Perceptual grouping allows us to bind together image elements into global objects and segregate them from the background, and evidence suggests neurons increase their response when their receptive fields contain elements perceived as a figure compared to a background. Across several projects, this thesis investigated this state-dependency at the level of topographic maps in human visual cortex. To this end, an approach to back-project brain measures into visual space was developed, allowing for fine-grained read-outs of topographic signatures. The first project focused on topographic signatures of global object perception and points to a non-generic involvement of higher object-sensitive cortex in perceptual grouping and a suppressionenhancement mechanism, possibly mediating figure-ground perception. The second project investigated topographic signatures of multifocal attention and shows that changes in topographic signatures under uni- or multifocal attention conditions cannot be distinguished from changes for test-retest data. The third project investigated flaws in quantifying topographic signatures and highlights that prior summaries of topographic signatures might be contaminated by regression artifacts. Collectively, these results underscore the potentials and challenges of investigating state-dependent topographic signatures.
With the growth of renewable technologies, patterns in the demand for mineral resources required have shifted, with increasing demand for emerging technologies and a growing reliance on a wider suite ...of elements. Given their extreme enrichment in many of these critical elements, ferromanganese (FeMn) crust deposits have the potential to be an important future resource but the variability at the scale of a prospective exploration site remains poorly understood. This problem is acute for FeMn crust understanding in the Atlantic Ocean where fewer in-depth studies have been carried out to date. This study provides a systematic investigation into the distribution of FeMn crusts and the variation in texture and composition at the scale of an individual seamount in the NE Atlantic. Relationships with environmental factors are investigated to provide an improved understanding of the formation, distribution and preservation processes that influence FeMn crust characteristics at this local scale. Ferromanganese crusts from Tropic Seamount were observed across a range of water depths and environments, and distribution modelling predicted highest presence probabilities in summit and flank regions. The distribution of FeMn crusts at this scale is driven by both the substrate characteristics and interactions of local topography and current regimes which exert fundamental controls on the distribution of exposed hard surface and the period of exposure for FeMn crust precipitation. Concentrations of Co (mean of 0.5 wt%) and Te (mean of 51 ppm) in Tropic Seamount FeMn crusts showed the highest concentrations in summit regions, and coincide with regions of active surface erosion. Significant variability in composition was observed across the seamount. Statistical analyses of composition, alongside element mapping and textural studies, showed that the high variability in FeMn crust composition is affected by local scale topography. Combined with the interaction with local current regimes, this can play a key role in determining the flux of detrital material to FeMn crusts and associated dilution of hydrogenetic FeMn phases.