Assessing disease risk at the wildlife–livestock interface: A study of Sierra Nevada bighorn sheep     

Deana L. Clifford  Brant A. Schumaker  Thomas R. Stephenson  Vernon C. Bleich  Maya L. Cahn  Ben J. Gonzales  Walter M. Boyce  Jonna A.K. Mazet   《Biological conservation》2009,142(11):2559-2568

Despite evidence that domestic sheep diseases threaten the persistence of bighorn sheep populations, the economic consequences of restricting domestic sheep grazing has polarized the debate, with some arguing that disease risk posed by domestic sheep has been exaggerated and grazing restrictions should be eased. We constructed a model to assess how different management strategies (grazing allotment closures, grazing time reductions, and reduced probability of stray domestic sheep) affect the risk of respiratory disease transmission from domestic sheep to endangered Sierra Nevada bighorn sheep, and to predict population-level impacts of an outbreak. Even when management strategies reduced risk of interspecies contact to less than 2% per year, our model predicted a 50% probability of a catastrophic respiratory disease outbreak during the next 10 bighorn sheep generations. If an outbreak occurs in the near future, the model predicts that the smallest Sierra Nevada bighorn sheep population would have a 33% probability of quasi-extinction. To eliminate all risk of contact and potential disease transmission, domestic sheep cannot be grazed on allotments that overlap with areas utilized by Sierra Nevada bighorn sheep. Where wildlife and domestic animal populations share limited habitat, and there is documented evidence of a substantial disease threat and extinction risk, stakeholders must recognize that the only way to eliminate contact and risk of disease transmission is to give priority to one species or the other. If conservation is the priority, difficult decisions will need to be made to balance trade-offs between economic livelihoods and species conservation.  相似文献   

Genetic control of dry matter,starch and sugar content in sweetpotato     

Ernest Baafi  Vernon E. Gracen  Joe Manu-Aduening  Essie T. Blay  Kwadwo Ofori  Edward E. Carey 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2017,67(2):110-118

Sweetpotato (Ipomoea batatas L. (Lam)) is a nutritious food security crop for most tropical households, but its utilisation is very low in Ghana compared to the other root and tuber crops due to lack of end-user-preferred cultivars. Knowledge on the genetic control of important traits such as dry matter, starch and sugar content of sweetpotato storage roots in a breeding population is critical for making breeding progress in developing sweetpotato varieties preferred by farmers and consumers. This study used diallel mating design to elucidate general combining ability and specific combining ability, to determine the gene action controlling storage root dry matter, starch and sugar content in sweetpotato and the heterotic potential of the traits to facilitate the crop’s improvement for increased utilisation. A general model for estimating genetic effects, GEAN II, was used to analyse the data. Genetic variability was seen for dry matter, starch and sugar content of sweetpotato and much of this genetic variation was additive in nature. The study also revealed significant heterosis in sweetpotato which offers opportunity for breeding non-sweet, high dry matter sweetpotato varieties that are preferred by farmers and consumers in Ghana.  相似文献   

2.9. Cabbage Root Fly Control in Cauliflowers in the South-West, 1964     

J. D. R. Vernon 《Plant pathology》1965,14(S1):12-12

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Aspects of protein metabolism and its controlAspects de la régulation du métabolisme des protéinesAspekte des Proteinstoffwechsels und seiner Kontrolle     

P.J. Buttery  B.G. Vernon 《Livestock Production Science》1980,7(2):111-120

Protein metabolism is a highly integrated process. The rates of deposition in a tissue depend on the balance between synthesis and degradation. While a lot is known about the factors controlling synthesis, e.g. amino acid supply, availability of messenger RNA, much less is known about the factors controlling degradation. Both these processes are markedly affected by hormones. When considering protein metabolism in the context of attempting to determine the factors controlling growth, it is essential to consider its integration between organs.  相似文献   

Biliary secretion of 14C and identification of 5,6-dihydro-5,6-dihydroxycarbaryl glucuronide as a biliary metabolite of [14C]carbaryl in the rat     

Craig B. Struble  Vernon J. Feil  Jerome C. Pekas  Jeffery W. Gerst 《Pesticide biochemistry and physiology》1983,19(1):85-94

The biliary secretion of ¹⁴C was observed in conscious, bile-fistulated rats given single oral doses of [¹⁴C]carbaryl (1.5, 30, and 300 mg/kg). Over 94% of the ¹⁴C was absorbed after 12 hr. From 15 to 46% of the ¹⁴C was secreted in bile, 10–40% in urine, and less than 1% in feces 12 hr after dosing. Three metabolites were isolated from bile and identified by mass and/or NMR spectrometric methods. These metabolites were: 5,6-dihydro-5,6-dihydroxycarbaryl glucuronide (12–18% of the biliary ¹⁴C), a conjugate(s) of carbaryl (12% of the biliary ¹⁴C), and conjugated isomers of hydroxy-carbaryl (2% of the biliary ¹⁴C). The majority of the biliary ¹⁴C remains to be identified.  相似文献   

Discourses of Elk Hunting and Grizzly Bear Incidents in Grand Teton National Park,Wyoming     

Marian E. Vernon  Zachary Bischoff-Mattson  Susan G. Clark 《Human Dimensions of Wildlife》2016,21(1):65-85

Incidents of human–wildlife conflict can solidify participant perspectives and expectations, and reveal underlying social and institutional dynamics. We describe and analyze two incidents of conflict between hunters and grizzly bears in 2011 and 2012. Both incidents were associated with the controversial elk hunt in Grand Teton National Park, Wyoming. We gathered quotes from opinion-editorials and interviews, categorized quotes according to type, and used cluster analysis to identify discourses and associated coalitions of participants. We examined how participants defined problems, used evidence, and advocated solutions in relation to these incidents. Participant discourses addressed technical and procedural issues of regional wildlife management that extended beyond these incidents, revealing divergent expectations about wildlife management on public lands. Existing decision-making processes dominated by government agencies do not appear to be addressing these expectations. We recommend an integrative, outside appraisal of regional elk management to address conflict and support ecologically sound decision-making that serves common interests.  相似文献   

Protein metabolism in animals treated with anabolic agents     

P. J. Buttery  B. G. Vernon 《Veterinary research communications》1983,7(1):11-17

One of the major factors controlling the deposition of protein in an animal is the activity of the hormones circulating in its blood. Many of the anabolic hormones interact with each other e.g. growth hormone and insulin and there is evidence for a direct interaction between catabolic and anabolic hormones e.g. testosterone and glucocorticoids. Exogenously administered hormone-like substances can have marked effects on animal growth. Diethyl stilbestrol acts like an oestrogen elevating plasma insulin and growth hormone concentration. Zeranol probably also acts in a similar way.Trenbolone acetate (TBA) an androgenic agent, is a very effective growth promotor especially in ruminants. Few changes of note in the endogenous plasma hormone concentrations in treated ruminants have been reported although the combined implant of TBA plus 17-oestradiol did depress plasma thyroxine in steers. We have used the rat as a model to test the effects of TBA on protein synthesis and protein degradation rate in the muscle of rats. Protein synthesis and protein degradation in the muscle of treated female rats was shown to be markedly reduced, the increased growth rate being brought about by a greater reduction in the rate of degradation than in the rate of synthesis. Cathepsin D activity in the muscle was also reduced. Attempts to demonstrate a direct action of TBA on muscle have been unsuccessful. The currently favoured hypothesis for the mode of action of TBA is that it interferes with catabolic action of glucocorticoids on muscle protein. This may not be the mode of action of all androgenic agents. Durabolin (nandrolone phenyl propionate) would appear to stimulate both protein synthesis and protein degradation, at least in the rat.  相似文献   

Genetic analysis of drought tolerance in adapted × exotic crosses of maize inbred lines under managed stress conditions     

M. A. Adebayo  A. Menkir  E. Blay  V. Gracen  E. Danquah  S. Hearne 《Euphytica》2014,196(2):261-270

Introduced maize (Zea mays L.) germplasm can serve as sources of favorable alleles to enhance performance in new maize varieties and hybrids under drought stress conditions. In the present study, the combining abilities of 12 exotic maize inbred lines from CIMMYT and 12 adapted maize inbred lines from IITA were studied for grain yield and other traits under controlled drought stress. The inbred lines from each institution were separated into groups using SSR-based genetic diversity and were intercrossed using a factorial mating scheme to generate 96 hybrids. These hybrids were evaluated under both controlled drought stress and well-watered conditions at Ikenne in Nigeria in 2010 and 2011. Average mean yields of hybrids under drought stress represented 23 % of the average yield of hybrids under full irrigation. General combining ability (GCA) effects accounted for 49–85 % of the observed variation for several traits recorded under both well-watered and drought stress conditions. Specific combining ability effects for grain yield, though positive in most hybrids, were not significant under drought stress conditions. All the twelve exotic and nine adapted lines had positive GCA effects (female, male, or both) for grain yield under either drought stress or full irrigation, or both environments. EXL03 and EXL15 that had positive and significant female and male GCA effects for grain yield under both environments can be used to improve their adapted counterparts for grain yield and drought tolerance. Normalized difference vegetation index had weak but significant correlation with grain yield.  相似文献   

The Effect of MSW Compost and Fertilizer on Extractable Soil Elements, Tuber Yield, and Elemental Concentrations in the Plant Tissue of Potato     

Philip R. Warman  A. Vernon Rodd  Peter Hicklenton 《Potato Research》2011,54(1):1-11

Municipal solid waste (MSW) compost is readily available in eastern Canada and may be a good source of fertility. A 3-year experiment evaluated the effects of MSW compost and fertilizer on soil fertility, elemental composition and yield of potato (Solanum tuberosum L.) grown in a sandy loam soil. Three rates of compost (MSW1, MSW2, and MSW3), one rate of fertilizer (NPK), and one mixture of 1/2 MSW1 compost and 1/2 NPK fertilizer were applied annually to plots in a three-crop rotation; each year the MSW1 rate attempted to match the rate of P applied in the NPK treatment. Mehlich-3 extracts were evaluated for 11 elements at two soil depths (0?C15 and 15?C30 cm). Potato shoots and roots or whole plants were assessed for 16 elements. Treatments had no consistent significant influence on marketable tuber yields although the NPK treatment produced mathematically the highest yields. After 3 years, treatments had influenced soil concentrations of K, Ca, S, Cu, Zn, and Na in Mehlich-3 extracts at the 0?C15 cm depth, but only the concentration of Na at the 15?C30 cm depth. The concentration of Mg in the plant tissue was consistently highest in plants fertilized with NPK; this treatment also produced higher Mn concentrations in the last 2 years. Shoot Cu concentrations were highest in the MSW3 plots. The compost did not increase heavy metal concentrations in shoot, root or whole-plant tissue and would be safe to use at agronomic rates of application.  相似文献   

Genotypic variation in abscisic acid content,carbon isotope ratio and their relationship with cassava growth and yield under moisture stress and irrigation     

J. Adjebeng-Danquah  J. Manu-Aduening  V. E. Gracen  S. K. Offei  I. K. Asante 《Journal of Crop Science and Biotechnology》2016,19(4):263-273

This study was carried out to assess genotypic variability in abscisic acid content, carbon isotope ratio, and their relationship to storage root yield and yield components in cassava under irrigation and moisture stress. The study involved 20 cassava genotypes arranged in randomized complete block design with three replications. Irrigation water was applied using a drip irrigation system with a discharge rate of approximately 5.33 L m^-2 hr^-1. Significant (P < 0.05) genotypic variability was observed for all physiological, growth, and yield traits assessed. Abscisic acid content was higher under stress than irrigation and negatively correlated with root yield (r = -0.45), harvest index (r = -0.43), and above-ground biomass yield (r = -0.20) indicating that it can be used as indirect selection criteria against unproductive genotypes. Carbon isotope ratio was significantly and positively correlated with above-ground biomass yield (r = 0.20) but not root yield (r = 0.09). Estimates of genotypic variability indicated high values for most of the growth and yield components but low heritability values for abscisic acid content, carbon isotope ratio, stomatal conductance, and root yield under stress conditions. However, higher estimates were recorded under irrigation and in the combined analysis. It was also found from this study that carbon isotope ratio influences above-ground biomass but not storage root yield under stress conditions. The results from this study provide useful information on the relationship between abscisic acid content, carbon isotope discrimination, and storage root yield in field-grown cassava.  相似文献