235 research outputs found

    Set Up and Calibration of a Spatial Tool for Simulating River Discharge of Western Java in Recent Decades: Preliminary Results and Assessments

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    This paper discusses a study of the application of global spatiotemporal climate datasets and the hydrological model STREAM (Spatial Tools for River Basin Environmental Analysis and Management Options). In the study, set up and calibration of STREAM for the reconstruction of monthly discharge for several locations in the western part of Java, Indonesia, for the period 1983 -2002 are carried out. The set up includes the preparation of monthly precipitation and temperature datasets, a digital elevation model of the domain being studied, and maps of land cover and soil water holding capacity. Discharge observations from six stations located mostly in the upper parts of major watersheds in the domain are used to calibrate the model by comparing simulated and observed discharge variables. The model performs reasonably well. Comparison between computed and observed mean monthly discharges yield correlation coefficients ranging from 0.72 to 0.93. The computed mean annual discharge in five out of six observation stations ranges between -8 and 5% with respect to the mean annual observed discharge. This study offers a tool which can be used for reconstructing historical discharg

    Spatial Decision Assistance of Watershed Sedimentation (SDAS): Development and Application

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    This paper discusses the development and application of a spatial tool for erosion modeling named Spatial Decision Assistance of Watershed Sedimentation (SDAS). SDAS computes export (yield) of sediment from watershed as product of erosion rate and sediment delivery ratio (SDR). The erosion rate is calculated for each raster grid according to a digital elevation model, soil, rain fall depth, and land cover data using the Universal Soil Loss Equation. SDR calculation is carried out for each spatial unit. A spatial unit is the smallest sub-watershed considered in the model and generated according to the TauDEM algorithm. The size of one spatial unit is assigned by the user as the minimum number of raster grids. SDR is inversely proportional to sediment resident time and controlled by rainfall, slope, soil, and land cover. Application of SDAS is demonstrated in this paper by simulating the spatial distribution of the annual sediment yield across the Citarum watershed in the northwest of Java, Indonesia. SDAS calibration was carried out based on sediment discharge observations from the upper catchment. We considered factors for hillslope flow depth and for actual and effective rainfall duration to fit the computed sediment yield to the observed sediment discharge. The computed sediment yield agreed with the observation data with a 7% mean relative accuracy

    Simulation of River Discharges in Major Watersheds of Northwestern Java From 1901 To 2006

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    This study is intended to simulate the river discharges in major watersheds of northwestern Java, Indonesia. The five largest watersheds are considered: Ciujung, Cisadane, Ciliwung, Citarum, and Cimanuk. The simulation period covers the 20th century and early 21st century, from January 1901 to June 2006, at a monthly time step. Discharge simulation was carried out using STREAM (Spatial Tools for River Basins and Environmental and Analysis of Management Option). The input data for the simulation are climate (precipitation and temperature), land cover and topographic data. Setup and analysis of input data are also part of this study. The Mann-Kendall test and linear regression were used to detect trends. Temperature datasets show statistically significant increasing trends for all periods and areas. Significant increasing trends of precipitation occurred in the latest 16-year period (1990-2006) in hilly and middle areas. A positive trend of simulated discharge is seen in all watersheds and periods. They are only significant for Ciujung (periods of 1950-2006 and 1975-2006), Cisadane (periods of 1950-2006 and 1990-2006), and Ciliwung (periods of 1950-2006, 1975-2006, and 1990- 2006). The most noteworthy trend is seen in the 1990-2006 period. Over the course of the 20th and early decade of the 21st century, monthly discharges have increased by 3% to 9%

    Non-rigid registration of serial intra-operative images for automatic brain shift estimation

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    Measurement of intra-operative brain motion is important to provide boundary conditions to physics-based deformation models that can be used to register pre- and intra-operative information. In this paper we present and test a technique that can be used to measure brain surface motion automatically. This method relies on a tracked laser range scanner (LRS) that can acquire simultaneously a picture and the 3D physical coordinates of objects within its field of view. This reduces the 3D tracking problem to a 2D non-rigid registration problem which we solve with a Mutual Information-based algorithm. Results obtained on images of a phantom and on images acquired intra-operatively that demonstrate the feasibility of the method are presented

    Biomechanical Simulation of Electrode Migration for Deep Brain Stimulation

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    International audienceDeep Brain Stimulation is a modern surgical technique for treating patients who suffer from affective or motion disorders such as Parkinson's disease. The efficiency of the procedure relies heavily on the accuracy of the placement of a micro-electrode which sends electrical pulses to a specific part of the brain that controls motion and affective symptoms. However, targeting this small anatomical structure is rendered difficult due to a series of brain shifts that take place during and after the procedure. This paper introduces a biomechanical simulation of the intra and postoperative stages of the procedure in order to determine lead deformation and electrode migration due to brain shift. To achieve this goal, we propose a global approach, which accounts for brain deformation but also for the numerous interactions that take place during the procedure (contacts between the brain and the inner part of the skull and falx cerebri, effect of the cerebro-spinal fluid, and biomechanical interactions between the brain and the electrodes and cannula used during the procedure). Preliminary results show a good correlation between our simulations and various results reported in the literature

    Birefringence of lead titanate (PbTiO 3

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    Mitochondrial quality control and neurological disease: an emerging connection

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    The human brain is a highly complex organ with remarkable energy demands. Although it represents only 2% of the total body weight, it accounts for 20% of all oxygen consumption, reflecting its high rate of metabolic activity. Mitochondria have a crucial role in the supply of energy to the brain. Consequently, their deterioration can have important detrimental consequences on the function and plasticity of neurons, and is thought to have a pivotal role in ageing and in the pathogenesis of several neurological disorders. Owing to their inherent physiological functions, mitochondria are subjected to particularly high levels of stress and have evolved specific molecular quality-control mechanisms to maintain the mitochondrial components. Here, we review some of the most recent advances in the understanding of mitochondrial stress-control pathways, with a particular focus on how defects in such pathways might contribute to neurodegenerative disease

    Application of Modular Rating Knowledge Assessment as an Innovative Learning Method

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    Оценка качества знаний специалистов среднего профессионального образования выступает одним из актуальных вопросов повышения качества образования. Методы оценки, релевантные уровню сформированности компетенций, представляют дисскусионный вопрос среди отечественных исследователей.Assessment of the quality of knowledge of specialists in secondary vocational education is one of the topical issues of improving the quality of education. Assessment methods that are relevant to the level of competence formation represent a discussion issue among domestic researchers
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