2,705 research outputs found
Mountain basin hydrologic study
December 2018.Includes bibliographical references.A long-standing problem for the Rocky Mountain region is that traditional meteorology and flood hydrology methods appear to significantly overestimate floods based on comparisons to paleoflood evidence and regional peak streamflow statistics. The Colorado Water Conservation Board (CWCB), Colorado Division of Water Resources (DWR), and state of New Mexico are conducting a $1.5 million study to develop improved estimates of extreme precipitation for the two-state region. Concurrently, DWR has been working to improve flood hydrology methods for the mountain region. Traditional flood hydrology methods utilize low infiltration rates to model flood runoff solely by an infiltration-excess mechanism. However, a recent but preliminary examination of the Gross Reservoir Basin suggests that saturation-excess runoff might be important for extreme precipitation events. The objectives of this research project are: (1) to determine the importance of saturation-excess runoff production for large storms that affect the design and performance of dams and transportation infrastructure and (2) to develop a generalized model for runoff production in mountainous basins that can be used by consultants to perform hydrologic analysis of dams and transportation infrastructure. In-situ soil moisture observations indicate that south-facing slopes often reached saturation during the September 2013 flood while north-facing slopes usually did not. They further suggest that saturation occurred first at the bottom of the soil layer and proceeded upward. These observations are consistent with saturation-excess runoff production. The preliminary model results also indicate that saturation-excess runoff production was the primary runoff production mechanism in South Boulder Creek during the September 2013 flood. Additionally, the model results show that south-facing slopes approached saturation while the north-facing slopes did not
Generation of soil moisture patterns at the catchment scale by EOF interpolation
International audienceSpatial patterns of soil moisture cannot be adequately characterized by direct measurement for most practical applications, so interpolation between observations is required. Interpolation of soil moisture is complicated because multiple hydrologic processes can affect soil moisture and these processes can introduce distinct modes of variation into the soil moisture patterns. In this paper, a new method to interpolate soil moisture data is presented. This method accepts a dataset of soil moisture at widely-spaced locations on multiple dates and produces fine-scale patterns of soil moisture on the same dates. The method first uses Empirical Orthogonal Function (EOF) analysis to decompose the dataset into a set of time-invariant patterns of covariation (EOFs) and a set of associated time series (called expansion coefficients or ECs) that indicate the importance of the patterns on each date. The method then uses a statistical test to retain only the most important EOFs, and these EOFs are interpolated to the desired resolution using a standard estimation or interpolation method. The interpolated EOFs are finally combined with the spatial averages and the ECs to construct the fine-scale soil moisture patterns. Using the Tarrawarra dataset, the EOF-based interpolation method is shown to outperform analogous direct interpolation methods, and this improved performance is observed when as few as two observation dates are available. The improved performance occurs because EOF analysis decomposes soil moisture roughly according to the controlling processes and the most important EOFs exhibit distinct but more consistent spatial structures than soil moisture itself. Less predictable variation is also separated into higher order EOFs, which are discarded by the method
Evaluation of the developmental capacity of cattle embryos after culture and deep-freezing
International audienc
Dataset associated with "Temporal Variations of NDVI and LAI and Interactions with Hydroclimatic Variables in a Large and Agro-Ecologically Diverse Region"
It contains the dataset used to produce Figure 2 in the manuscript and to estimate relationships of hydroclimatic variables with vegetation indices. Each variable is a monthly regional average (for combined Sacramento and San Joaquin river basins, California) and spans from October 2002 to September 2015. These regional averages have been estimated using different datasets which are cited in the manuscript. Description of dataset is as follows:
1. Dataset 1: Regional averages of monthly hydroclimatic and vegetation anomalies
2. Dataset 2: Mean and standard deviations of monthly hydroclimatic and vegetation anomalies
3. Dataset 3: Prewhitened time series of monthly hydroclimatic and vegetation anomalies
4. Dataset 4: Prewhitened-detrended time series monthly hydroclimatic and vegetation anomalies
5. Dataset 5: Annual time series of regional hydroclimatic and vegetation anomalies
See supplementary information provided with the manuscript for more information.Satellite based vegetation indices are increasingly used to characterize seasonal and interannual variations in vegetation as well as vegetation’s response to hydroclimatic variability. However, differences in the behavior of vegetation indices are not well understood over large spatial extents (e.g., 0.5° or larger). We hypothesize that normalized difference vegetation index (NDVI) and leaf area index (LAI) can exhibit different behaviors due to different relationships with hydroclimatic variables. To test this hypothesis, observations of monthly precipitation, discharge, temperature, vapor pressure deficit, evapotranspiration, and total water storage anomalies (TWSA) are processed for the combined Sacramento and San Joaquin river basins in California for 13 water years (October 2002-September 2015). Estimates of NDVI and LAI are obtained for the same period from MODerate resolution Imaging Spectroradiometer (MODIS). The seasonal cycle of NDVI peaks 2-3 months earlier than LAI. The seasonal variation in NDVI follows the seasonality of TWSA (i.e. water availability) whereas the seasonal cycle of LAI follows the seasonality in mean temperature and vapor pressure deficit (i.e. atmospheric water demand). Cross-correlation analyses of NDVI and LAI with the hydroclimatic variables show that LAI is more strongly correlated with most of the hydroclimatic variables considered.This work was supported by a grant provided by Bureau of Educational and Cultural Affairs, US Department of State under the umbrella of foreign Fulbright scholarship program
Risk of acquired drug resistance during short-course directly observed treatment of tuberculosis in an area with high levels of drug resistance.
BACKGROUND: Data on the performance of standardized short-course directly observed treatment (DOTS) of tuberculosis (TB) in areas with high levels of drug resistance and on the potential impact of DOTS on amplification of resistance are limited. Therefore, we analyzed treatment results from a cross-sectional sample of patients with TB enrolled in a DOTS program in an area with high levels of drug resistance in Uzbekistan and Turkmenistan in Central Asia. METHODS: Sputum samples for testing for susceptibility to 5 first-line drugs and for molecular typing were obtained from patients starting treatment in 8 districts. Patients with sputum smear results positive for TB at the end of the intensive phase of treatment and/or at 2 months into the continuation phase were tested again. RESULTS. Among 382 patients with diagnoses of TB, 62 did not respond well to treatment and were found to be infected with an identical Mycobacterium tuberculosis strain when tested again; 19 of these patients had strains that developed new or additional drug resistance. Amplification occurred in only 1.2% of patients with initially susceptible or monoresistant TB strains, but it occurred in 17% of those with polyresistant strains (but not multidrug-resistant strains, defined as strains with resistance to at least isoniazid and rifampicin) and in 7% of those with multidrug-resistant strains at diagnosis. Overall, 3.5% of the patients not initially infected with multidrug-resistant TB strains developed such strains during treatment. Amplification of resistance, however, was found only in polyresistant Beijing genotype strains. CONCLUSIONS: High levels of amplification of drug resistance demonstrated under well-established DOTS program conditions reinforce the need for implementation of DOTS-Plus for multidrug-resistant TB in areas with high levels of drug resistance. The strong association of Beijing genotype and amplification in situations of preexisting resistance is striking and may underlie the strong association between this genotype and drug resistance
Proposta de organização e visualização de grande quantidade de imagens orbitais através de web services.
The organization of satellite imagery seeks to facilitate the presentation and manipulation of spatial information in projects of Land Management's Strategic area from Embrapa Satellite Monitoring, enabling integration between mapped data and interoperability of image data and mapped regions. As a way to standardize this organization, we followed the recommendations of national and international bodies that deal with the standardization of geographic metadata, specifically satellite images. To view this integration, a webmapping interface was created. A webmapping must be prepared to meet the needs of relationship between user and product. In this paper we propose a standardized structure for storage and maintenance of images obtained by satellite sensors aiming its availability on the web through web map services, examples of interoperability. The non-interoperability prevents sharing of information and computing resources. The visualization of web map services takes place through a webmapping that benefits from the organization structure of satellite images proposed in this paper. The hierarchical organization proposed research assistance of satellite images. As they are entered into the database, now new images will be organized in a logical structure, without affecting the search for listings older images. The webmapping allows a direct link between the metadata and geospatial data visualization. Combining web services based on Geographic Information Systems (GIS) in conjunction with the Flex technology allows the creation of Rich Internet Applications (RIA) giving the user more possibilities of interaction via the Web
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