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101.
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
102.
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
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Geoffrey Ndegwa Miyuki Iiyama Dieter Anhuf Udo Nehren Sabine Schlüter 《Agroforestry Systems》2017,91(6):1043-1055
Agroforestry systems in Sub-Saharan African drylands are complex and heterogeneous in nature even under similar biophysical conditions. This can be attributed to household needs and socioeconomic status which influence the species and utility of the adopted trees. This has an impact on the trees establishment and management system through planting or Farmer Managed Natural Regeneration (FMNR). This study evaluates how trees for different utilities are managed and which socioeconomic factors influence these decisions. The study used primary data collected in Mutomo District, Kenya through a household survey based on a structured questionnaire. A paired sample t-test was done to assess the preferred mode of adopting trees for different utilities while factor analysis was used to characterize the households as either planting trees or practicing FMNR. Multiple linear regression using household regression factor scores as independent variables and socioeconomic indicators as dependent variables was done to ascertain which socioeconomic factors affect tree adoption. The results show that trees planted were mostly exotic species valued for their nutrition and commercial value, while FMNR was used for subsistence products and environmental services. Household size, livestock levels and mobility had a positive correlation with tree planting, while income, access to markets and roads had an inverse correlation. Access to natural woodland, distance to the nearest motorable road and land size had a positive correlation with tree protection. It is hoped that this knowledge will act as a reference point when designing agroforestry projects in similar areas to ensure they are more aligned to specific site and household conditions. 相似文献
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Humberto J.O. Ramos M. Geoffrey Yates Emanuel M. Souza 《Soil biology & biochemistry》2011,43(8):1626-1638
Bacteria are extraordinarily diverse microorganisms with a huge potential to benefit environmental and agricultural systems. Comprehensive studies in complex habitats such as soils and plants have led to the development of genetic tools to evaluate gene expression and bacterial colonization under controlled or environmental conditions and to obtain genetically engineered organisms for environmental release. In addition, current advances in genomic and metagenomic research will add to the number of genes with potential for biotechnological applications, which will require the development of appropriate genetic systems to fulfill their potential for both industrial and agricultural applications. The aim of the present review is to assess the approaches and recent progress in vector design and genetic tools to study and manipulate plant-bacterial interactions, as well as strategies to construct genetically modified strains for environmental release. 相似文献
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