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151.
We tested the following hypotheses: (i) breeding schemes with genomic selection are superior to breeding schemes without genomic selection regarding annual genetic gain of the aggregate genotype (ΔG(AG) ), annual genetic gain of the functional traits and rate of inbreeding per generation (ΔF), (ii) a positive interaction exists between the use of genotypic information and a short generation interval on ΔG(AG) and (iii) the inclusion of an indicator trait in the selection index will only result in a negligible increase in ΔG(AG) if genotypic information about the breeding goal trait is known. We examined four breeding schemes with or without genomic selection and with or without intensive use of young bulls using pseudo-genomic stochastic simulations. The breeding goal consisted of a milk production trait and a functional trait. The two breeding schemes with genomic selection resulted in higher ΔG(AG) , greater contributions of the functional trait to ΔG(AG) and lower ΔF than the two breeding schemes without genomic selection. Thus, the use of genotypic information may lead to more sustainable breeding schemes. In addition, a short generation interval increases the effect of using genotypic information on ΔG(AG) . Hence, a breeding scheme with genomic selection and with intensive use of young bulls (a turbo scheme) seems to offer the greatest potential. The third hypothesis was disproved as inclusion of genomically enhanced breeding values (GEBV) for an indicator trait in the selection index increased ΔG(AG) in the turbo scheme. Moreover, it increased the contribution of the functional trait to ΔG(AG) , and it decreased ΔF. Thus, indicator traits may still be profitable to use even when GEBV for the breeding goal traits are available.  相似文献   
152.
The increasing cultivation of energy crops in the last few years may have an impact on changes in the environment, biodiversity and the landscape. Due to a longer rest of soil and reduced application of pesticides, perennial crops such as short rotation coppice (SRC) offer benefits that can have a positive effect on the biodiversity. However, to assess the overall impact of SRC on biodiversity, information on the quality of SRC as a habitat for animals and plants, depending on the woody species over several years and the management is required. In the years 2010 and 2011, the diversity of ground beetles of willow and poplar in SRC were examined using pitfall traps at three sites in southwestern Germany. It was distinguished between species, variety and age of the SRC. At all sites ground beetle diversity was significantly higher in the studied poplar stands than in those of the willows. In addition, significant differences between the varieties could be observed depending on the location and the year of examination. The older stands of the SRC showed in general a higher level of diversity. Due to the different variety preference of ground beetles it is recommended to plant a mixture of varieties. Furthermore, SRC of different ages should be established side by side, as with increasing tree age species of the open area decrease and forest species settle. Overall, SRC offer the potential to increase biodiversity in natural landscapes.  相似文献   
153.
Paratuberculosis may be diagnosed by clinical, bacteriological and immunological methods, but so far only the demonstration of M. paratuberculosis is considered a definite proof of the infection. World-wide use is being made of the complement fixation (CF) test as a valuable immunological test for diagnosis of clinical cases, but its low specificity and sensitivity makes its value problematic in non-clinical cases.  相似文献   
154.
To improve genetic gain of breeding programs for village poultry production, breeding schemes with observations obtained in village production systems using individual (VIO) and group recording (VGO) were examined under different levels of genotype-by-environment-interactions (GxE). GxE was modeled by varying the correlation between traits measured in the breeding station and village environments for bodyweight (rg_BW) and egg production (rg_EP). Relative and absolute genetic gains obtained from VIO and VGO were used for comparison between the schemes. Results showed that village observations significantly improved genetic gains compared to the scheme without birds tested in the village. The improvement was only slightly larger with individual observations than with group observations. Higher rg_BW and rg_EP led to lower relative genetic gain, but a higher absolute gain of VIO and VGO. It is recommended to apply a breeding scheme using group recording of village performance when strong GxE in breeding for village poultry is expected.  相似文献   
155.
Accumulation in soil and leaching to groundwater of fentin acetate were studied in the laboratory using two types of Dutch sandy soil differing in organic matter content. Mobility, adsorption, transformation and formation of intermediates were determined in unsaturated soil columns, batch shaking systems and soil incubation systems. Samples were analyzed for monophenyltin, diphenyltin and triphenyltin compounds after methylation. Therefore the transformation products diphenyltin oxide and phenyltin acid were determined separately. Both were detected in soil and pore water. Adsorption indicated that these fungicides are immobile in both types of soil. Nevertheless a small fraction was found in the column leachate. After 1 yr of percolation 5.5 and 20.2% of the dose was recovered as total phenyltin residue in the soil of low and high organic matter content, respectively; all the residue was in the upper 10 cm. The half-life of fentin acetate in soil with 1% organic C varied between 47 and 70 days and between 115 and 140 days in soil with 2% organic C. If fentin acetate is applied annually, one can expect to find an ultimate accumulation level of organotin residues of up to 25% of the annual dose in the plough layer.  相似文献   
156.
The effect of changes in feed intake on auscultatable gastrointestinal sounds has not been systematically studied. Disagreement also is present in the literature about variation in sounds according to the quadrant of auscultation. Gastrointestinal sounds were recorded over the center of the left dorsal, left ventral, right ventral, and right dorsal quadrants and over the middle of the right abdominal flank. During 24 hours (n = 4) or 48 hours (n = 5) of fasting, there was a reduction in the intensity of gastrointestinal sounds as assessed by analysis of sound recordings. There was also a reduction in the number of mixing-like and propulsive-like sounds heard by 2 blinded observers. After refeeding, there was a marked increase in sound. Sound intensity varied among abdominal quadrants, but blinded observers did not notice significant differences in the number of mixing-like sounds. The left dorsal quadrant was quieter than others during fasting and refeeding. The right ventral quadrant appeared to be least affected by fasting, and sounds were louder over the right ventral and right middle quadrants than over the others. The blinded observers' perceptions of sound correlated poorly with one another and with objective measures of sound intensity. This experiment demonstrates the effectiveness of computerized analysis of abdominal sound in detecting a reduction in the intensity of gastrointestinal sounds during fasting and their return during refeeding. The left dorsal quadrant was quieter than other quadrants, likely because of its position over the small colon. There was considerable observer variation in the number of intestinal sounds heard.  相似文献   
157.
Interest in native species is growing across the tropics as reforestation of degraded lands becomes more widespread. In this study four tree species native to Panama - Cedrela odorata, Pachira quinata, Samanea saman, and Tabebuia rosea - were grown on rural farms at two dry tropical sites in Panama for up to five years. Survivorship and growth data at these “on-farm” trials are compared to data recorded from nearby experimental or “species selection” trial sites and evaluated in terms of soil fertility and management. Participant farmers were also asked about their interest in planting trees in general as well as their interest in 61 species grown in the species selection trial.Although, on-farm survivorship was variable and generally lower than that found on the species selection trial, one species (S. saman) experienced high and consistent survivorship. High survivorship combined with growth data from farms at both sites for this species suggests it would be a good candidate for extension projects working with rural farmers. Survivorship of other species appears more sensitive to farmer management and/or local site conditions. Generally lower growth on the Los Santos farms as compared to the species-selection trial is attributed to the lower soil fertility (plant available P) at the on-farm sites compared to the species selection trial. In contrast, only one species - P. quinata - had a growth variable found to be significantly lower between the on-farm and species selection trial sites in Rio Hato. C. odorata, P. quinata T. rosea can all be used in on-farm conditions with consideration to specific site and management conditions.By 2009, approximately 80% of the farmers planting trees still wished to participate in tree planting activities. All of the farmers no longer wishing to continue with the project expressed slow growth rates of trees as a principal reason. All but one of these farmers had growth rates for his/her trees markedly below those of the species selection trial nearby. Some farmers wishing to continue had very high mortality rates (>70% for all species), suggesting non-tangible benefits for participating in project activities. Other species that were not tested on-farm but grew well in the species-selection trials and were of interest to local farmers are discussed.As long as specific site and management conditions are carefully considered, data from species selection trials can be useful in informing tree planting projects with rural farmers; however, care should be taken to manage expectations.  相似文献   
158.
A polyamide nucleic acid (PNA) was designed by detaching the deoxyribose phosphate backbone of DNA in a computer model and replacing it with an achiral polyamide backbone. On the basis of this model, oligomers consisting of thymine-linked aminoethylglycyl units were prepared. These oligomers recognize their complementary target in double-stranded DNA by strand displacement. The displacement is made possible by the extraordinarily high stability of the PNA-DNA hybrids. The results show that the backbone of DNA can be replaced by a polyamide, with the resulting oligomer retaining base-specific hybridization.  相似文献   
159.
The hegemony of Western science, inherent in international development projects, often increases the poverty and oppression of Third World women by pre-empting alternative realities. In African and Asian agrarian societies women grow from 60 to 90% of the food (World Bank, 1989); they hold incredible potential to increase food production. Their ability to operate under more marginal conditions than their male counterparts would seem to indicate that they have developed valuable knowledge— knowledge often generated in response to limited access to the more tangible resources offered by development assistance to male farmers. Recognizing the marginalization of women in the Third World, the Women in Development (WID) network was established during the 1970's to produce knowledge about women, fill in the gaps, and set the record straight. But knowledge creation for these purposes leaves underlying paradigms of Western science-based development unquestioned. Research from a feminist standpoint is used to challenge the objectivity and reliability of EuroAmerican development science. To date, WID has documented and analyzed the causes and consequences of Third World women's oppression with no substantial results to end them. Alternatively, feminist research validates women's perceptions of their reality, helping ordinary people to understand the connections between their experiences and broader social, economic, and political struggles. The paper emphasizes research pursued in order to act, closely linking knowing to doing to promote the emancipation of oppressed groups. A feminist standpoint is used to privilege the perspective of rural women in developing countries and ask: “What are the implications of the standard EuroAmerican approach to science for maximizing the potential contributions of rural women to agricultural development?” Some of these implications are illustrated with examples from on-farm research in Nigeria. To some extent, implications can be addressed by constructing meanings to structure a symbolic framework that includes female farmers and other disadvantaged groups.  相似文献   
160.
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