Development of a method for Bayesian nonparametric ROC analysis with application to an ELISA for Johne's disease in dairy cattle   总被引：2，自引：1，他引：1  

Fosgate GT  Scott HM  Jordan ER 《Preventive veterinary medicine》2007,81(1-3):178-193

Six hundred and sixty-eight dairy cattle were tested for Johne's disease using a direct-fecal real-time polymerase chain reaction (rt-PCR), fecal culture, and serum enzyme-linked immunosorbent assay (ELISA). Likelihood ratios (LRs) were estimated for five categories of sample-to-positive (S/P) values for the ELISA: <0.1, 0.1-0.249, 0.25-0.399, 0.4-0.999, > or =1.0. The statistical method assumed a single multinomial model for cross-classified rt-PCR, fecal culture results, and ELISA category strata. Conditional dependence between tests was investigated by the inclusion of all possible pairwise dependence terms. Sensitivity covariance between ELISA and fecal culture was estimated as 0.017. Estimates for the accuracy of the ELISA at the usual cutoff of 0.25S/P was 67.2% and 95.2% for sensitivity and specificity, respectively for a model that adjusted for the dependence between ELISA and fecal culture. The area under the receiver-operating characteristic (ROC) curve (95% probability interval) for the ELISA was 0.867 (0.796, 0.928). Point estimates for likelihood ratios (95% probability intervals) were 0.24 (0.11, 0.38), 1.52 (0.48, 3.27), 2.49 (0.31, 13.4), 6.33 (2.54, 16.5), and 103 (25.0, 2412) for the categories <0.1, 0.1-0.249, 0.25-0.399, 0.4-0.999, >/=1.0, respectively. Assumptions concerning the underlying distribution of test results for infected and uninfected animals were not necessary and this model can be employed for the general estimation of LRs and ROC curves in absence of knowledge concerning true disease status.  相似文献   

Effect of preoperative administration of tepoxalin on induction dose of injectable anesthetics in dogs     

Matthews NS  Belz KM  Fosgate GT  Pappas C 《Veterinary therapeutics : research in applied veterinary medicine》2007,8(1):5-17

Medications given preoperatively have the potential to affect the induction dose of injectable anesthetics, which could result in an anesthetic overdose. Tepoxalin is an NSAID approved for the treatment of arthritis in dogs in the United States and hence could be administered in patients requiring anesthesia. In this study, administration of a single dose or a 10-day course of tepoxalin did not affect the induction dose (dose that allowed intubation) of propofol, thiopental, or ketamine-diazepam and also did not affect the time required for dogs to recover from anesthesia.  相似文献   

P.J. Miller and M.J. Loates, Collins Pocket Guide to the Fish of Britain and Europe     

Geoffrey Potts 《Aquarium Sciences and Conservation》1998,2(2):93-94

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Integrated Water Resources Management   总被引：1，自引：0，他引：1  

Per Stålnacke  Geoffrey D. Gooch 《Irrigation and Drainage Systems》2010,24(3-4):155-159

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Book review: Reef fisheries,edited by Nicholas V.C. Polunin and Callum M. Roberts,Chapman & Hall,London 1996, xviii + 477 pp. Price: £75. ISBN 0 412 60110 9.     

Geoffrey W. Potts 《水产资源保护:海洋与淡水生态系统》1997,7(2):180-180

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Charcoal production through selective logging leads to degradation of dry woodlands:a case study from Mutomo District,Kenya     

Geoffrey M NDEGWA 《干旱区科学》2016,8(4):618-631

Provision of woodfuel is an important ecosystem service of dry forests and woodlands.However,charcoal production through selective logging of preferred hardwood species has the potential to alter the physiognomic composition of the residual or re-growth woodlands and may lead to their deterioration and degradation.This study,conducted through forest inventory in Mutomo District in Kenya,assessed the impact of charcoal production on unprotected dry woodlands in terms of tree density,targeted species basal area,species richness,evenness and Shannon diversity.The parameters of the disturbed woodlands were evaluated for significant differences with those of the neighbouring protected Tsavo East National Park,which served as a reference for an ecologically undisturbed ecosystem.By evaluating a consequence of tree harvesting for charcoal production,this study confirmed the overall significant differences between the protected and unprotected woodlands in all the tested parameters.To confirm if the differences in the land-covers of the woodlands had any influence on their degradation,all mentioned parameters were compared between the four differentiated classes and their respective control plots in the protected areas.At the "land-cover level",the statistically significant difference in the basal area of tree species preferred for charcoal production between the protected and unprotected open trees confirms that the class with a high density of large mature trees is the prime target of charcoal producers.In addition,there seems to be a general trend of lower values of tree species richness,evenness and Shannon diversity for the unprotected woodlands subjected to charcoal production.On the other hand,the disturbed woodlands display the potential to recover through their comparably high saplings density.The findings make an important contribution to the discourse on the impact of charcoal production in dry woodlands,a topic that is highly controversial among researchers.  相似文献   

Biochar use in a legume–rice rotation system: effects on soil fertility and crop performance     

Samuel T. Partey  Kazuki Saito  Richard F. Preziosi  Geoffrey D. Robson 《Archives of Agronomy and Soil Science》2016,62(2):199-215

The aim of this study was to determine whether by applying biochar, it is possible to augment the beneficial effects of legume–crop rotation systems on soil fertility and crop performance. Repeated experiments were established in 2012 and 2013 in South-western Benin using a split-split plot design. Two legumes, Mucuna pruriens (mucuna) and Vigna unguiculata (cowpea), were planted for 42 days on biochar-amended and unamended plots and subsequently cut and applied as mulch 5 days before planting rice. Rice plants were either fertilized or not using a fertilizer rate of 60, 30, and 30 kg ha^?1 of N, P₂O₅, and K₂O, respectively. The results showed that the application of legume green manures and fertilizer, either singly or in combination, improved soil nutrient availability, CEC, shoot yield, and grain yield of rice on both biochar-amended and unamended plots. However, the effect was significantly (p < 0.05) greater on biochar-amended plots. The mean grain yield for all cropping seasons was 1.8 t ha^?1 for biochar-amended plots and 1.3 t ha^?1 for unamended plots. The greater grain yield of rice on biochar-amended plots was associated with improved soil fertility and increased N uptake.  相似文献   

Mapping of quantitative trait loci for floral scent compounds in cowpea (Vigna unguiculata L.)     

Mebeaselassie Andargie  Jette T. Knudsen  Remy S. Pasquet  Bhavani S. Gowda  Geoffrey M. Muluvi  Michael P. Timko 《Plant Breeding》2014,133(1):92-100

Floral scent is a very important trait in plant evolution. Currently, little is known about the inheritance of floral scent in cowpea (Vigna unguiculata L.) or changes that might have occurred during its domestication. Therefore, we analysed scent volatiles and molecular markers in a population of 159 F₇ recombinant inbred lines derived from a cross of a domesticated blackeye cowpea cultivar, ‘524B’ and a wild accession ‘219‐01’. Using gas chromatography‐mass spectrometry (GC–MS) 23 volatile compounds were identified that fall into five general functional categories. Twenty‐two of the compounds displayed quantitative variation in the progeny, and a total of 63 QTLs influencing the amounts of these volatiles were mapped onto the cowpea genetic marker map. Although QTLs for volatile compounds putatively involved in cowpea flower scent were found on 9 of the 11 cowpea chromosomes, they were not evenly distributed with QTLs mainly clustered on LGs 1, LGs 2 and LG 4. Our results serve as a starting point for both more detailed analyses of complex scent biosynthetic pathways and the development of markers for marker‐assisted breeding of scented rose varieties.  相似文献   

Environmental risk factors for equine West Nile virus disease cases in Texas     

Michael P. Ward  Courtney A. Wittich  Geoffrey Fosgate  Raghavan Srinivasan 《Veterinary research communications》2009,33(5):461-471

West Nile Virus (WNV) was first detected in the Texas equine population during June 2002. Infection has since spread rapidly across the state and become endemic in the equine population. Environmental risk factors associated with equine WNV attack rates in Texas counties during the period 2002 to 2004 were investigated. Equine WNV attack rates were smoothed using an empirical Bayesian model, because of the variability among county equine populations (range 46−9,517). Risk factors investigated included hydrological features (lakes, rivers, swamps, canals and river basins), land cover (tree, mosaic, shrub, herbaceous, cultivated and artificial), elevation, climate (rainfall and temperature), and reports of WNV-positive mosquito and wild bird samples. Estimated county equine WNV attack rate was best described by the number of lakes, presence of broadleaf deciduous forest, presence of cultivated areas, location within the Brazos River watershed, WNV-positive mosquito status and average temperature. An understanding of environmental factors that increase equine WNV disease risk can be used to design and target disease control programs.  相似文献   

A rapid technique for screening banana cultivars for resistance to Xanthomonas wilt     

Leena Tripathi  John Odipio  Jaindra Nath Tripathi  Geoffrey Tusiime 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(1):9-19

The banana Xanthomonas wilt disease (BXW) has threatened the livelihood of millions of farmers in East Africa. Use of resistant varieties is the most cost-effective method of managing this bacterial disease. A reliable and rapid screening method is needed to select resistant banana varieties. An in vitro screening method was developed for early evaluation of Xanthomonas wilt resistance using small tissue culture-grown plantlets. Eight cultivars of banana were screened with sixteen isolates of Xanthomonas campestris pv. musacearum using this method. There were significant differences (P < 0.0001) in susceptibility among the various banana cultivars tested, whereas no significant difference (P = 0.92) in pathogenicity was observed between the pathogen isolates. The cv. Pisang Awak (Kayinja) was found to be highly susceptible and Musa balbisiana resistant. Nakitembe was found to be moderately resistant while cvs Mpologoma, Mbwazirume, Sukali Ndiizi, FHIA-17 and FHIA-25 were susceptible. The susceptibility of these cultivars was further tested in vivo by artificial inoculation of potted plants with similar results. This study shows that an in vitro screening test can serve as a convenient, cheap and rapid screening technique to discriminate BXW-resistant from BXW-susceptible banana cultivars.  相似文献