The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Xiaodong Ming - One of the best experts on this subject based on the ideXlab platform.

  • spatial downscaling of trmm precipitation data based on the orographical effect and meteorological conditions in a Mountainous Area
    Advances in Water Resources, 2013
    Co-Authors: Jian Fang, Peijun Shi, Xiaodong Ming
    Abstract:

    Abstract The lack of high resolution precipitation data has posed great challenges to the study and management of extreme rainfall events. Satellite-based rainfall products with large Areal coverage provide a potential alternative source of data where in situ measurements are not available. However, the mismatch in scale between these products and model requirements has limited their application and demonstrates that satellite data must be downscaled before being used. This study developed a statistical spatial downscaling scheme based on the relationships between precipitation and related environmental factors such as local topography and pre-storm meteorological conditions. The method was applied to disaggregate the Tropical Rainfall Measuring Mission (TRMM) 3B42 products, which have a resolution of 0.25° × 0.25°, to 1 × 1 km gridded rainfall fields. The TRMM datasets in accord with six rainstorm events in the Xiao River basin were used to validate the effectiveness of this approach. The downscaled precipitation data were compared with ground observations and exhibited good agreement with r 2 values ranging from 0.612 to 0.838. In addition, the proposed approach provided better results than the conventional spline and kriging interpolation methods, indicating its promise in the management of extreme rainfall events. The uncertainties in the final results and the implications for further study were discussed, and the needs for additional rigorous investigations of the rainfall physical process prior to institutionalizing the use of satellite data were highlighted.

Chenhsiang Lee - One of the best experts on this subject based on the ideXlab platform.

  • clinicoepidemiologic characteristics of scrub typhus and murine typhus a multi center study in southern taiwan
    Journal of Microbiology Immunology and Infection, 2019
    Co-Authors: Yichin Chang, Kuangche Kuo, Wu Sun, Jiunnong Lin, Chunghsu Lai, Chenhsiang Lee
    Abstract:

    Abstract Background This study aimed to offer key features to differentiate scrub typhus (ST) and murine typhus (MT) at the early stage of the diseases and provide clinicoepidemiologic characteristics of ST and MT in southern Taiwan, a region where both diseases are endemic. Comparison of doxycycline treatment efficacy between the two diseases by matching disease severity and delayed treatment had never been investigated. Methods We reviewed the medical records of cases of ST and MT in four hospitals in southern Taiwan. Propensity-score matching was used to analyze the defervescence curves between patients with doxycycline-treated ST and MT by log-rank test. Results Between 2004 and 2016, 265 ST and 63 MT cases were diagnosed. The number of cases of ST was significantly related to temperature (Rs = 0.77) and rainfall (Rs = 0.63). Island Area exposure, arthropod bite, eschar, and lymphadenopathy were only recorded in ST patients. Multivariate analysis revealed that Mountainous Area exposure (odds ratio [OR], 11.0; 95% confidence interval [CI], 4.4–27.2) was an independent predictor for ST, while contact with rats (OR, 8.4; 95% CI, 3.3–21.3) was that for MT. After propensity-score matching, there was no difference in defervescence curves between these two rickettsioses treated with doxycycline (p = 0.24). Conclusion In the present study, island Area exposure, arthropod bite, eschar, and lymphadenopathy were unique manifestations of ST. Mountainous Area exposure is a predictive factor for ST, while contact with rats predicted MT. There was no difference in defervescence time between these two rickettsioses after doxycycline treatment.

P Droogers - One of the best experts on this subject based on the ideXlab platform.

  • a high resolution precipitation 2 step mapping procedure hip2p development and application to a tropical Mountainous Area
    Remote Sensing of Environment, 2014
    Co-Authors: Johannes E Hunink, Walter W Immerzeel, P Droogers
    Abstract:

    Understanding the spatial and temporal variability of precipitation in tropical high mountain Areas remains a key challenge. Point measurements are often not sufficient to capture the strong spatial variability particularly in mountain regions. Satellite remote sensing allows capturing the spatial heterogeneity of precipitation, yet it is generally characterized by significant bias. Rainfall satellite products such as those coming from the Tropical Rainfall Measuring Mission (TRMM) are being continuously improved and an increasing amount of high- and medium-resolution remote sensing data on biophysical surface properties is becoming available. Here we present a methodology that blends two TRMM products with remote sensing data on vegetation and topography to quantify the spatial distribution of precipitation in Areas where direct observations are lacking. The approach assumes that vegetation cover, the topography and satellite-derived estimates of rainfall are reasonable indirect measures of ground-based precipitation. The methodology is evaluated for an Area in the Andes of Ecuador. The results show that around 40% of the variance in weekly precipitation is explained by these proxies. During the drier periods of the year, vegetation is the strongest proxy. In the very wet Areas and during the wet periods vegetation is usually in a climax development phase with no development trends to correlate with rain, and the other proxies dominate precipitation estimation. A cross-validation procedure in which each one of the weather stations is sequentially excluded from the analysis, was applied to test the performance of the methodology. The performance was satisfactory, and as expected it is related to the density of the weather station network and temporal rainfall variability. Overall we conclude that the methodology is useful for Areas with very high variable conditions, where sufficient ground-data is available to establish the relationships with the different remote sensing datasets.

Thierry Lissolo - One of the best experts on this subject based on the ideXlab platform.

  • performances of constructed wetlands for municipal wastewater treatment in rural Mountainous Area
    Hydrobiologia, 2002
    Co-Authors: Gerard Merlin, Jeanluc Pajean, Thierry Lissolo
    Abstract:

    A global performance evaluation of an experimental Horizontal SubSurface Flow Constructed Wetlands (HSSF) was made after 6 years of functioning. This wetland is situated in French prealpine mountain, at 720 m elevation. The HSSF process treatment consists in a three-stage system dimensioned for 350 People Equivalent. Different helophytes were planted such as Typha latifolia, Phragmites australis and Scirpus maritimus. The mean hydraulic residence time for sewage was closed to 4–5 days, but in summer the mean pollutant residence time increases to 6 days due to an important evapotranspiration. There is no clogging of the gravel matrix and the hydraulic conductivity was very good and stabilized. Removal pollutant efficiency was determinate at each stages. There was a high removal of total suspended solids (TSS) all year around with an average of 95.6% (±3.6). More than 80% of removal occurred in the first stage. Physical processes (decantation, filtration) associated with biological oxidation were the principal factors of this removal. For COD and BOD5, removal efficiency in the first stage were close to 60% on average and more than 90% at the outlet of the wetland. These results are similar to those observed with SSFW in many cases. Influence of temperature seems very weak because there were no significant seasonal variations of the process efficiency. Minimum effluent quality standards (30 mg l−1 TSS; 120 mg l−1 COD; 40 mg l−1 BOD5) were always respected. In cold periods, nutrients uptake was reduced but remained up to 60% in average. Mean bacterial removal efficiency was about two order of magnitude (99%) but can reach up to five order of magnitude in summer. These cyclic variations follow a sinusoidal variation around an annual mean. Pollutants removals were correlated to their respective loadings and no limits has been observed except for nitrogen. These results confirm that SSFW, an ecotechnology, should be considered as an alternative to conventional treatment methods (activated sludge, fixed biofilm) for small communities even in Mountainous Area.

Leandro Goncalves Oliveira - One of the best experts on this subject based on the ideXlab platform.

  • stonefly plecoptera fauna of streams in a Mountainous Area of central brazil abiotic factors and nymph density
    Revista Brasileira De Zoologia, 2002
    Co-Authors: Pitágoras Da Conceição Bispo, Claudio G Froehlich, Leandro Goncalves Oliveira
    Abstract:

    The stonefly (Pleeoptera) nymphs of streams of the Almas River basin, Pirenopolis, Goias State, Central Brazil, and some abiotie factors that might affect their temporal distribution were studied. Nymphs were sampled monthly (June 1993 to July 1994) in five stations with a Surber sampler, and each sample consisted of 20 units totalling 2 m2. In each station, stream velocity, discharge, temperature, electrical conductivity and pH were measured in order to assess their influence on the density of nymphs. Nymphs were identified to genus level. In general, the annual variation in density of nymphs, in four stations, showed that the seasonal variation was not clearly influenced by the annual rain cycle. In the case of the one of the stations, where numbers of stonefly nymphs were low and the anthropic action high, there was a density peak in the rainy season. This peak was probably related to dilution of the organie pollution in the rainy season, improving the environmental conditions for the Pleeoptera.

  • stonefly plecoptera fauna in a Mountainous Area of central brazil abiotic factors and nymph density
    Revista Brasileira De Zoologia, 2002
    Co-Authors: Pitágoras Da Conceição Bispo, Claudio G Froehlich, Leandro Goncalves Oliveira
    Abstract:

    The stonefly (Pleeoptera) nymphs of streams of the Almas River basin, Pirenopolis, Goias State, Central Brazil, and some abiotie factors that might affect their temporal distribution were studied. Nymphs were sampled monthly (June 1993 to July 1994) in five stations with a Surber sampler, and each sample consisted of 20 units totalling 2 m2. In each station, stream velocity, discharge, temperature, electrical conductivity and pH were measured in order to assess their influence on the density of nymphs. Nymphs were identified to genus level. In general, the annual variation in density of nymphs, in four stations, showed that the seasonal variation was not clearly influenced by the annual rain cycle. In the case of the one of the stations, where numbers of stonefly nymphs were low and the anthropic action high, there was a density peak in the rainy season. This peak was probably related to dilution of the organie pollution in the rainy season, improving the environmental conditions for the Pleeoptera.

  • stonefly plecoptera fauna in a Mountainous Area of central brazil composition and adult phenology
    Revista Brasileira De Zoologia, 2002
    Co-Authors: Pitágoras Da Conceição Bispo, Claudio G Froehlich, Leandro Goncalves Oliveira
    Abstract:

    A survey of the stonefly (Plecoptera) fauna of streams of the Almas River basin, Pirenopolis, Goias State, Central Brazil, is presented as well as data of some factors that could affeet the temporal distribution of the adults. For checking adult phenology, light sources were used in three stations from June 1993 to Jully 1994. The sampled individuais were identified to species or morphospecies, as possible. In this study, 301 individuais belonging to the perlid genera Anacroneuria Klapalek, 1909, Kempnyia Klapalek, 1916 and Macrogynoplax Enderlein, 1909 were collected. Adults of most species were collected along the studied period, except for those of Kempnyia that were restricted to the warm-rainy season, the same pattern for this genus in southeastern Brazil. Although adults of most species were collected along most of the studied period, the largest number of adults was collected in the months with larger mean temperatures, showing a clear seasonality in abundance.