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排序方式: 共有453条查询结果,搜索用时 15 毫秒
1.
J Hahn 《DTW. Deutsche tier?rztliche Wochenschrift》1989,96(2):72-73
New biotechnical methods in reproduction have been introduced in animal breeding via embryo transfer. There are no serious objections against these methods as long as the variety of species is reassured and the animal protection law is considered. More substantial objections exist against genetic engineering methods which alter the genome of animals. Beside for legal protection there is a strong public demand for the adequete awareness and responsibility of scientists who are active in this field. Comprehensive information on such research projects can lead to a better understanding of the aims and methods and might, therefore, help to reduce inadequate apprehensions. 相似文献
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A neurologic syndrome in Golden Retrievers presenting as a sensory ataxic neuropathy 总被引:1,自引:0,他引:1
Jäderlund KH Orvind E Johnsson E Matiasek K Hahn CN Malm S Hedhammar A 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2007,21(6):1307-1315
BACKGROUND: A sensory ataxic neuropathy has been observed in Swedish Golden Retrievers recently. ANIMALS: Twenty-one affected Golden Retrievers. METHODS: Clinical and neurologic status, electrophysiologic, and pathologic status as well as pedigree analyses were evaluated. RESULTS: Clinical signs had an insidious onset between 2 and 8 months of age and a slowly progressive course. Affected dogs were ataxic and dysmetric. They had abnormal postural reactions and decreased spinal reflexes but no apparent muscle atrophy. Clinical pathology, radiography, and electrophysiology of motor systems were all within reference values. Sensory nerve conduction results of affected dogs were significantly different from those of a group of control dogs. Necropsy revealed a chronic progressive central and peripheral sensorimotor axonopathy; the proprioceptive pathways were most severely affected. CONCLUSIONS AND CLINICAL IMPORTANCE: This disease in these Golden Retrievers is distinct from other canine breed-related neurodegenerative diseases or hereditary neurodegenerative diseases described in humans. Pedigree analyses indicated a hereditary background, but the mode of inheritance could not be established. 相似文献
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成都平原不同耕作模式的农田效应研究—— II.土壤综合质量评价 总被引:1,自引:0,他引:1
【目的】研究成都平原不同耕作模式对土壤质量性状的影响,探索建立适合当地生产条件的土壤质量评价体系,筛选出适宜该地的耕作模式,为提高当地土壤生产力水平、改善土壤质量提供借鉴。【方法】通过长期定位试验获取不同耕作模式对土壤性状及作物生产指标的影响效应,采用主成分分析的方法筛选评价指标,运用因子分析法对土壤质量进行综合评价。【结果】筛选出的评价土壤综合质量的指标在不同土壤层次存在明显差别:0—10 cm土层的主要影响因子为毛管孔隙度、土壤比重、土壤饱和渗水速率、土壤紧实度、土壤有机质;10—20 cm土层的主要影响因子为总孔隙度、非毛管孔隙度、饱和渗水速率、土壤吸湿水、土壤紧实度;0—20 cm土层的主要影响因子为非毛管孔隙度、土壤比重、土壤饱和渗水速率、土壤紧实度。其中,不同土层的共同影响因子——土壤饱和渗水速率和土壤紧实度是目前当地土壤质量的限制因子。土壤质量综合评价结果表明0—10 cm土层以麦稻双免耕作模式最好,10—20 cm土层麦免+稻旋最好,0—20 cm土层麦免+稻旋最好。【结论】在本研究的试验条件和当地实际情况下,对成都平原土壤质量具有良好效益的耕作模式为麦免+稻旋模式。 相似文献
6.
Azin Rekowski Monika A. Wimmer Bernd Hitzmann Bernhard Hermannseder Heike Hahn Christian Zrb 《植物养料与土壤学杂志》2020,183(2):260-270
Background: Nitrogen losses is an economic problem for wheat production and a high risk to the environment. Therefore, improved N fertilizer management is a key to increasing the N efficiency and minimizing N losses. To increase N efficiency, enhanced fertilizers such as urea combined with urease inhibitor can be used. Aims: The aim of present study was to evaluate the effects of different N forms on grain storage protein subunits in winter wheat and to examine whether the observed changes correlate with parameters of baking quality. Methods: The investigation was performed over two consecutive years at two locations in Germany. Protein subunits were analyzed by SDS‐PAGE. Results: Protein concentrations were similarly increased after fertilization with ammonium nitrate and urea + urease inhibitor. Analysis of the individual storage protein fractions indicated that both fertilizers specifically enhanced ω‐gliadins and HMW glutenins, but the effect was more pronounced in the ammonium nitrate treatment. Application of urea + urease inhibitor had greater influence on the protein composition and resulted in higher specific baking volume as well as the best fresh keeping ability, in comparison with urea treatment. Conclusion: Considering that the urea + urease inhibitor treatment resulted in almost comparable improvements of NUE and baking quality, with the additional benefit of reduced N losses in combination with easy handling, urea + urease inhibitor can be recommended as a viable alternative to both urea alone and ammonium nitrate treatments. This opens up an opportunity for the reduction of N loss in wheat production when use of urea is preferred. 相似文献
7.
Measurements of the equation of state of deuterium at the fluid insulator-metal transition 总被引:1,自引:0,他引:1
GW Collins Da Silva LB P Celliers DM Gold ME Foord RJ Wallace A Ng SV Weber KS Budil R Cauble 《Science (New York, N.Y.)》1998,281(5380):1178-1181
A high-intensity laser was used to shock-compress liquid deuterium to pressures from 22 to 340 gigapascals. In this regime deuterium is predicted to transform from an insulating molecular fluid to an atomic metallic fluid. Shock densities and pressures, determined by radiography, revealed an increase in compressibility near 100 gigapascals indicative of such a transition. Velocity interferometry measurements, obtained by reflecting a laser probe directly off the shock front in flight, demonstrated that deuterium shocked above 55 gigapascals has an electrical conductivity characteristic of a liquid metal and independently confirmed the radiography. 相似文献
8.
Pablo M. Vergara Luis O. Meneses Audrey A. Grez Madelaine S. Quiroz Gerardo E. Soto Christian G. Pérez-Hernández Paola A. Diaz Ingo J. Hahn Andrés Fierro 《Landscape Ecology》2017,32(2):279-293
Context
Interactions between landscape-scale processes and fine-grained habitat heterogeneity are usually invoked to explain species occupancy in fragmented landscapes. In variegated landscapes, however, organisms face continuous variation in micro-habitat features, which makes necessary to consider ecologically meaningful estimates of habitat quality at different spatial scales.Objectives
We evaluated the spatial scales at which forest cover and tree quality make the greatest contribution to the occupancy of the long-horned beetle Microplophorus magellanicus (Coleoptera: Cerambycidae) in a variegated forest landscape.Methods
We used averaged data of tree quality (as derived from remote sensing estimates of the decay stage of single trees) and spatially independent pheromone-baited traps to model the occurrence probability as a function of multiple cross-scale combinations between forest cover and tree quality (with scales ranging between 50 and 400 m).Results
Model support and performance increased monotonically with the increasing scale at which tree quality was measured. Forest cover was not significant, and did not exhibit scale-specific effects on the occurrence probability of M. magellanicus. The interactive effect between tree quality and forest cover was stronger than the independent (additive) effects of tree quality and particularly forest cover. Significant interactions included tree quality measured at spatial scales ≥200 m, but cross-scale interactions occurred only in four of the seven best-supported models.Conclusions
M. magellanicus respond to the high-quality trees available in the landscape rather than to the amount of forest per se. Conservation of viable metapopulations of M. magellanicus should consider the quality of trees at spatial scales >200 m.9.
S Romagnoli C Stelletta C Milani D Gelli ME Falomo A Mollo 《Reproduction in domestic animals》2009,44(S2):36-39
This study was conducted to evaluate clinical efficacy of deslorelin for inhibiting reproduction in the bitch. Ten adult healthy bitches or bitches with mammary neoplasia for which owners were requesting suppression of cyclicity without performing gonadectomy were administered a 4.7- or a 9.4-mg deslorelin implant subcutaneously. The first implant of deslorelin was administered in anoestrus (n = 5) or in dioestrus (n = 5). Treatment was repeated every 5 months for as long as necessary based on the clinical situation of the dog and owner's desires. Some of the bitches implanted in anoestrus came in heat within 4–15 days after treatment, while none of the bitches implanted in dioestrus showed heat during treatment. Suppression of reproductive cyclicity was successfully achieved in 6/10 bitches for 1–4 years. No behavioural and local/general side-effects were observed in any of the treated bitches. The 4.7-mg deslorelin implant may work well for suppression of cyclicity provided that it is administered in dioestrus and at intervals of 4.5 months. A 9.4-mg implant may be more suitable for this use although its efficacy may also be shorter than 12 months. Owner compliance is an important limiting factor. 相似文献
10.
Gaschen B Taylor J Yusim K Foley B Gao F Lang D Novitsky V Haynes B Hahn BH Bhattacharya T Korber B 《Science (New York, N.Y.)》2002,296(5577):2354-2360
Globally, human immunodeficiency virus-type 1 (HIV-1) is extraordinarily variable, and this diversity poses a major obstacle to AIDS vaccine development. Currently, candidate vaccines are derived from isolates, with the hope that they will be sufficiently cross-reactive to protect against circulating viruses. This may be overly optimistic, however, given that HIV-1 envelope proteins can differ in more than 30% of their amino acids. To contend with the diversity, country-specific vaccines are being considered, but evolutionary relationships may be more useful than regional considerations. Consensus or ancestor sequences could be used in vaccine design to minimize the genetic differences between vaccine strains and contemporary isolates, effectively reducing the extent of diversity by half. 相似文献