435 research outputs found

    Prediction of runoff and discharge in the Simiyu River (tributary of Lake Victoria, Tanzania) using the WetSpa model

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    International audienceA spatially distributed hydrologic model (WetSpa) is used to estimate daily river water discharge in the Simiyu river a tributary of Lake Victoria, Tanzania. The model combines topography, landuse and soil maps, and observed daily meteorological time series to predict discharge hydrographs and the spatial distribution of hydrological parameters in the catchment. The elevations in the catchment range from 2000 to 1100 m at the outlet, with average slope of 1.4%. The dominant landuse types are, wasteland, grassland, bushland, cultivated land, and a very small area is covered by surface water. The dominant soil types are sandy loam, followed by sandy clay loam, clay loam, clay, loam and sandy clay. There are two distinctive seasons in the Simiyu catchment. Short rains mainly in November, December and January, and long rains in March to May, resulting in a total average annual precipitation of 700 to 1000 mm. The annual potential evapotranspiration is about 1300 mm, and the river discharge at the catchment outlet ranges from 0 to about 200 m3/s. Global parameters of the model are calibrated using three years of daily observed discharge values measured at the mouth of the river at Lake Victoria. The estimated average travel time of the runoff to the outlet of the catchment is about 2.4 d and maximum 8 d for the most remote areas. The model results also show that the surface runoff and interflow provide respectively 38.6% and 61.4% of the total runoff, while the contribution of groundwater drainage is nil. The absence of groundwater drainage is probably due to the high evaporation demand of the atmosphere, which accounts for about 90% of the total precipitation being lost by evapotranspiration. The annual water balance estimated with the model reveals that the total outflow to Lake Victoria is about 500×106 m3 per year, which occurs mainly in the wet seasons, i.e. from March to May and from November to January. The volume of runoff produced by agricultural land amounts to about 9% of the total runoff annually

    Simulation of hydrological processes in the Simiyu River, tributary of Lake Victoria, Tanzania

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    A spatially-distributed hydrologic model (WetSpa) is used to simulate hydrologic processes in the Simiyu River, a tributary of Lake Victoria, Tanzania. The model combines digital maps of topography, land-use and soil texture with observed daily meteorological time series to predict discharge hydrographs and spatial distribution of hydrologic parameters in the basin. The model was calibrated using 3 years of daily observed discharge measured at the mouth of the river at Lake Victoria. The estimated average travel time of the runoff to the outlet of the basin is about 2.4 days and a maximum of 8 days for the most remote areas. The model results show that the surface runoff and interflow provide, respectively, 38.6% and 61.4% of the total discharge, while the contribution of groundwater drainage is about nil. The absence of groundwater drainage is likely due to the high evaporative demand of the atmosphere, which accounts for about 90% of the total precipitation being lost by evapotranspiration. The annual water balance estimated with the model reveals that the total outflow to Lake Victoria is about 475 x 106 m3 per year, which occurs mainly in the wet seasons, i.e. from March to May and from November to January. The discharge volume produced by agricultural land amounts to about 43 x 106 m3 and may carry agrochemicals to Lake Victoria

    Blood and tissue biomarker analysis in dogs with osteosarcoma treated with palliative radiation and intra-tumoral autologous natural killer cell transfer.

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    We have previously reported radiation-induced sensitization of canine osteosarcoma (OSA) to natural killer (NK) therapy, including results from a first-in-dog clinical trial. Here, we report correlative analyses of blood and tissue specimens for signals of immune activation in trial subjects. Among 10 dogs treated with palliative radiotherapy (RT) and intra-tumoral adoptive NK transfer, we performed ELISA on serum cytokines, flow cytometry for immune phenotype of PBMCs, and PCR on tumor tissue for immune-related gene expression. We then queried The Cancer Genome Atlas (TCGA) to evaluate the association of cytotoxic/immune-related gene expression with human sarcoma survival. Updated survival analysis revealed five 6-month survivors, including one dog who lived 17.9 months. Using feeder line co-culture for NK expansion, we observed maximal activation of dog NK cells on day 17-19 post isolation with near 100% expression of granzyme B and NKp46 and high cytotoxic function in the injected NK product. Among dogs on trial, we observed a trend for higher baseline serum IL-6 to predict worse lung metastasis-free and overall survival (P = 0.08). PCR analysis revealed low absolute gene expression of CD3, CD8, and NKG2D in untreated OSA. Among treated dogs, there was marked heterogeneity in the expression of immune-related genes pre- and post-treatment, but increases in CD3 and CD8 gene expression were higher among dogs that lived > 6 months compared to those who did not. Analysis of the TCGA confirmed significant differences in survival among human sarcoma patients with high and low expression of genes associated with greater immune activation and cytotoxicity (CD3e, CD8a, IFN-γ, perforin, and CD122/IL-2 receptor beta). Updated results from a first-in-dog clinical trial of palliative RT and autologous NK cell immunotherapy for OSA illustrate the translational relevance of companion dogs for novel cancer therapies. Similar to human studies, analyses of immune markers from canine serum, PBMCs, and tumor tissue are feasible and provide insight into potential biomarkers of response and resistance

    Examination of the role of Mycoplasma bovis in bovine pneumonia and a mathematical model for its evaluation

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    The authors screened 34 large cattle herds for the presence of Mycoplasma bovis infection by examining slaughtered cattle for macroscopic lung lesions, by culturing M. bovis from lung lesions and at the same time by testing sera for the presence of antibodies against M. bovis. Among the 595 cattle examined, 33.9% had pneumonic lesions, mycoplasmas were isolated from 59.9% of pneumonic lung samples, and 10.9% of sera from those animals contained antibodies to M.bovis. In 25.2% of the cases M. bovis was isolated from lungs with no macroscopic lesions. The proportion of seropositive herds was 64.7%. The average seropositivity rate of individuals was 11.3% but in certain herds it exceeded 50%. A probability model was developed for examining the relationship among the occurrence of pneumonia, the isolation of M. bovis from the lungs and the presence of M. bovis specific antibodies in sera

    Interdigital dermatitis, heel horn erosion, and digital dermatitis in 14 Norwegian dairy herds

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    AbstractThe aim of this study was to assess infectious foot diseases, including identification and characterization of Dichelobacter nodosus and Treponema spp., in herds having problems with interdigital dermatitis (ID) and heel horn erosion (E) and in control herds expected to have few problems. We also wanted to compare diseased and healthy cows in all herds. The study included 14 dairy herds with a total of 633 cows. Eight herds had a history of ID and E, and 6 were control herds. All cows were scored for lameness, and infectious foot diseases on the hind feet were recorded after trimming. Swabs and biopsies were taken from the skin of 10 cows in each herd for bacterial analyses. In total, samples were taken from 34 cows with ID, 11 with E, 40 with both ID and E, and 8 with digital dermatitis (DD), and from 47 cows with healthy feet. Swabs were analyzed for identification and characterization of D. nodosus by PCR, culture, virulence testing, and serotyping. Biopsies were analyzed by fluorescent in situ hybridization regarding histopathology, identification, and characterization of Treponema spp., and identification of D. nodosus. Interdigital dermatitis was the most frequent foot disease, with a prevalence of 50.4% in problem herds compared with 26.8% in control herds. Heel horn erosion was recorded in 34.8% of the cows in problem herds compared with 22.1% in control herds. Dichelobacter nodosus was detected in 97.1% of the cows with ID, in 36.4% with E, in all cows with both ID and E, in all cows with DD, and in 66.0% of cows with healthy feet. All serogroups of D. nodosus except F and M were detected, and all isolates were defined as benign by the gelatin gel test. Treponema spp. were detected in 50.0% of the cows with ID, in 9.1% with E, in 67.5% with ID and E, in all cows with DD, and in 6.4% of those with healthy feet. In total, 6 previously described phylotypes (PT) of Treponema were detected: PT1, PT3, PT6, PT13, and PT15 in cows with ID, PT1 in a cow with E, and PT1, PT2, PT3, PT6, and PT13 in cows with both ID and E. One new phylotype (PT19) was identified. The epidermal damage score was higher but the difference in inflammatory response of the dermis was minor in cows with ID versus those with healthy feet. Fisher’s exact test revealed an association between ID and D. nodosus, and between ID and Treponema spp. Logistic regression revealed an association between both ID and E and dirty claws (odds ratios=1.9 and 2.0, respectively). Our study indicates that D. nodosus, Treponema spp., and hygiene are involved in the pathogenesis of ID
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