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941.
Data derived from synthetic aperture radar (SAR) are widely employed to predict soil properties, particularly soil moisture and soil carbon content. However, few studies address the use of microwave sensors for soil texture retrieval and those that do are typically constrained to bare soil conditions. Here, we test two statistical modelling approaches—linear (with and without interaction terms) and tree-based models, namely compositional linear regression model (LRM) and random forest (RF)—and both nongeophysical (e.g., surface soil moisture, topographic, etc) and geophysical-based (electromagnetic, magnetic and radiometric) covariates to estimate soil texture (sand %, silt % and clay %), using microwave remote sensing data (ESA Sentinel-1). The statistical models evaluated explicitly consider the compositional nature of soil texture and were evaluated with leave-one-out cross-validation (LOOCV). Our findings indicate that both modelling approaches yielded better estimates when fitted without the geophysical covariates. Based on the Nash–Sutcliffe efficiency coefficient (NSE), LRM slightly outperformed RF, with NSE values for sand, silt and clay of 0.94, 0.62 and 0.46, respectively; for RF, the NSE values were 0.93, 0.59 and 0.44. When interaction terms were included, RF was found to outperform LRM. The inclusion of interactions in the LRM resulted in a decrease in NSE value and an increase in the size of the residuals. Findings also indicate that the use of radar-derived variables (e.g., VV, VH, RVI) alone was not able to predict soil particle size without the aid of other covariates. Our findings highlight the importance of explicitly considering the compositional nature of soil texture information in statistical analysis and regression modelling. As part of the continued assessment of microwave remote sensing data (e.g., ESA Sentinel-1) for predicting topsoil particle size, we intend to test surface scattering information derived from the dual-polarimetric decomposition technique and integrate that predictor into the models in order to deal with the effects of vegetation cover on topsoil backscattering.  相似文献   
942.
943.
Thirty pet ferrets with adrenocortical disease (ACD) of varying severity and duration were evaluated for response to a single administration of a slow release 4.7 mg deslorelin acetate implant. Clinical response to deslorelin was monitored via a physical examination performed every 3 to 4 months. Adrenal ultrasound measurements were taken every 3-4 months until clinical relapse. At clinical relapse, duration of symptom suppression and adrenal size and growth were determined. Administration of a single 4.7 mg implant of deslorelin acetate resulted in significant decreases in the clinical signs and hormonal concentrations associated with ACD. Within 14 days post-implant, vulvar swelling, pruritus, sexual behaviors and aggression decreased or disappeared. Hair re-growth was evident by 4-6 weeks post implant. Within two months post deslorelin implant, plasma concentrations of steroid hormones decreased: mean estradiol concentration decreased 28%; 17-hydroxyprogesterone levels decreased 89% and androstenedione levels decreased 88%. The response to a single 4.7 mg implant of deslorelin acetate was transitory. The mean ± SD time to recurrence of clinical signs was 17.6 ± 5.0 months (range, 8.0-30.0 months). Repeated ultrasound measurements revealed no statistical difference in size of the adrenals (right or left) before, during the months of deslorelin implant and at clinical relapse. Slow release 4.7 mg deslorelin implants can effectively be used to temporarily eliminate the clinical signs and reduce steroid hormone concentrations in ferrets with ACD. This dose of deslorelin does appear to influence adrenal tumor growth causing a decrease in adrenal size in some ferrets, and mild enlargement of adrenal glands in most ferrets with 2 of 30 implanted animals developing large tumors before clinical relapse. The long-term effect of treatment with deslorelin on adrenal tumor pathology requires additional investigation. At this time, surgical removal of the adrenal tumor remains the only curative treatment; however, 4.7 mg deslorelin implants are useful in the long-term management of ACD hormone-induced sequelae and may be as effective assurgical management.  相似文献   
944.
Industrial soy protein isolates (SPIs) due to differences in their processing conditions may differ both in composition and in degree of hydrolysis. As a result, they display different performance in food production and final food properties like consistency and taste. To address this issue, a fast, cheap, and simple method for screening and characterization is required. In this article, the successful analysis of soy protein isolates, a complex mixture of proteins with glycinin and beta-conglycinin as major components, by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is demonstrated. The preparation implements a fast extraction of the proteins from the raw SPI either under neutral or reducing conditions. The extracts are analyzed subsequently by MALDI-TOF-MS without further purification. Results of the two conditions are compared. Finally, different SPIs from different suppliers are analyzed and compared concerning their consistency. The method could be applied to other plant proteins and mixtures thereof. Since the composition and intactness of different subunits play important roles in functional properties of soy proteins, rapid methods for fingerprinting of different industrial soy protein sources will be valuable tools for successful product formulation.  相似文献   
945.
946.
Lufenuron is a benzoylphenyl urea-derived insecticide that has been recently introduced as a novel treatment for fungal infections in horses. The purposes of this study were to determine (1) the in vitro efficacy of lufenuron against Aspergillus and Fusarium spp. and (2) the ability of lufenuron to reach efficacious blood concentrations after PO administration in horses. Fungal colonies isolated from diseased equine corneas were tested against lufenuron solutions up to 700 microg/mL. Twenty-one adult horses received 1 of 3 PO lufenuron treatment regimens: 5 mg/kg body weight (BW) q24h for 3 days, 20 mg/kg BW q24h for 3 days, or 60 mg/ kg BW q24h for 1 day. Blood samples were collected up to 96 hours after drug administration and analyzed by high-performance liquid chromatography. Statistical analyses of lufenuron blood concentrations were performed by analysis of variance and Fischer's Least Significant Difference test, with statistical significance set at P < .05. Lufenuron showed no effect on the in vitro growth of Aspergillus or Fusarium spp. Lufenuron was detected in the blood of all but 1 horse and showed no adverse effects. The maximum blood lufenuron concentration (83.5 +/- 58.7 microg/L) was lower than the concentrations proven to be ineffective in vitro in this study. Further therapeutic use of lufenuron as an antifungal agent in horses should be based on proven efficacy against specific strains of clinically relevant fungi with pharmacokinetic data demonstrating sufficient lufenuron concentrations in target tissues.  相似文献   
947.
ABSTRACT: To investigate immune responses upon re-infection with Lawsonia intracellularis, local and peripheral humoral and cell-mediated immune responses to primary and challenge inoculations were studied in 22 pigs. Pigs were orally inoculated with virulent L. intracellularis at the age of 5-6 weeks, treated with antibiotics and challenged with a re-inoculation (RE) at the age of 12 weeks. Treatment control (TC) pigs received only the primary inoculation and challenge control (CC) pigs received only the secondary inoculation at 12 weeks of age. Following this regimen, all RE pigs were protected against the re-infection as defined by reduced colonisation and pathology of intestinal mucosa, absence of bacterial shedding and without increase in serum acute phase protein response. In the protected RE pigs, serum IgG responses were variable with both high and low responders. Serum IgA responses were not boosted by the re-inoculation, since identical intestinal IgA responses developed in response to the inoculation in both the susceptible CC pigs and the protected RE pigs. A memory recall cell-mediated immune response developed in RE pigs which was significantly stronger compared to the primary response in age-matched CC pigs as assessed by whole blood IFN-γ assay and by calculation of IFN-γ integrated median fluorescence intensity (iMFI) after flow cytometry. The major IFN-γ producing cells were identified as CD8+ and CD4+CD8+ double positive lymphocytes. The results indicate that cell-mediated immune responses are likely mediators of protective immunity against L. intracellularis, with CD8+ effector cells and CD4+CD8+ double positive memory T cells as main contributors to the antigen-specific IFN-γ production.  相似文献   
948.
副猪嗜血杆菌在仔猪保育期死亡中的作用及其防制   总被引:5,自引:0,他引:5  
美国明尼苏达大学兽医学院的SimoneO liveira、CarlosPijoan和RobertMorrison等认为 ,副猪嗜血杆菌 (Haemophilusparasuis)感染近来成了仔猪保育期死亡的主要病因 ,尽管造成保育期仔猪副猪嗜血杆菌感染增加的原因还不完全清楚。对此 ,现已提出了一些假设 ,包括认为早期隔离断奶以及猪繁殖和呼吸综合征猪繁殖和呼吸综合征并发感染。副猪嗜血杆菌感染的防制取决于我们对受害猪群中流行病学的理解以及对于其在仔猪保育期死亡中作用 (原发性病原体或是继发性病原体 )的确定。原发性病原体上述学者引述Pijoan(1997)的看法 ,认为养猪业中的一…  相似文献   
949.
950.
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