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1.
The rate of reduction of chinchilla cochlear microphonic response with exposure to steady noise is less at lower body temperatures and greater at higher body temperatures. Before exposure to noise, this auditory response is invariant within the range of temperatures employed. The mechanism of reduction of cochlear response appears to involve processes sensitive to body temperature.  相似文献   
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The electromagnetic field of visible light performs approximately 10(15) oscillations per second. Although many instruments are sensitive to the amplitude and frequency (or wavelength) of these oscillations, they cannot access the light field itself. We directly observed how the field built up and disappeared in a short, few-cycle pulse of visible laser light by probing the variation of the field strength with a 250-attosecond electron burst. Our apparatus allows complete characterization of few-cycle waves of visible, ultraviolet, and/or infrared light, thereby providing the possibility for controlled and reproducible synthesis of ultrabroadband light waveforms.  相似文献   
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PCR-genotyping of barley seedlings using DNA samples from tissue prints   总被引:1,自引:0,他引:1  
Screening of large numbers of plant samples with polymerase chain reaction (PCR)‐based techniques is a central task in marker‐assisted plant breeding and molecular genetics. While PCR and electrophoresis have been streamlined as a result of high‐throughput analysis methods, the collection of plant material and its processing to make it accessible for reliable amplification reactions remain labour‐intensive, costly and not amenable to automation. As an alternative to traditional extraction protocols, DNA can be bound to specially treated paper (FTA‐paper). For PCR analysis, instead of being added as a liquid suspension, DNA is then released from small paper disks that are immersed into the reaction mixture. In the present study, several parameters were investigated for the successful amplification of various single‐copy sequence characterized amplified region markers from barley tissue prints. The results show that the FTA‐paper approach offers a quick, reliable and low‐cost alternative for PCR screening even in a crop plant with a large genome.  相似文献   
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RNA-directed DNA polymerase was isolated from the liver, spleen, and myeloblasts of chickens that had been infected with virus of avian myeloblastosis. The enzyme was chromatographically purified from the myeloblasts and brought to about 1,000-fold concentration. The method consisted in cell fractionation, lysis of the microsomal fraction, chromatography on Sephadex G-200 and phosphocellulose, as well as ultracentrifugation in the glycerol gradient. The cellular DNA polymerases alpha and beta were clearly separated from the DNA polymerase of avian myeloblastosis virus and could be distinguished from one another by template-specific reactions. The viral DNA polymerase activities in the microsomal fractions of liver, spleen, and myeloblasts were compared with one another. The amount of avian myeloblastosis virus and related DNA polymerase recorded from the myeloblasts was about six times that in the liver and four times higher than that in the spleen. The procedure described, together with the use of cell fractionation and gel filtration, is an appropriate method for biochemical detection of avian oncorna viruses in cells.  相似文献   
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We demonstrated how the subcycle evolution of the electric field of light can be used to control the motion of bound electrons. Results are presented for the dissociative ionization of deuterium molecules (D2 --> D+ + D), where asymmetric ejection of the ionic fragment reveals that light-driven intramolecular electronic motion before dissociation localizes the electron on one of the two D+ ions in a controlled way. The results extend subfemtosecond electron control to molecules and provide evidence of its usefulness in controlling reaction dynamics.  相似文献   
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Research indicates that consumers are particularly concerned about the safety of meat. More highly processed meat is perceived as more unsafe than fresh or natural meats, i.e., consumers trust processed meat less. This paper studies the relationship between perceived trust and day-to-day purchase behavior for meat, giving special attention to the degree of meat processing. Controlling for trust in food chain actors and demographic and socio-economic variables, actual meat purchases of Canadian households are linked to answers from a commissioned food attitudes survey completed by the same households. Expenditures for processed and total meat (but not for fresh meat) are significantly different by three levels of trust in the food industry. Consumer with the lowest trust levels consume less (especially of processed meat) compared to those with higher trust levels. However, in a multivariate setting, trust shows no effect on fresh or processed meat purchases with or without demographic and socio-economic control variables, suggesting that the impact of trust on meat purchases is only small. However, the low trusting consumer segment could potentially be a target for marketing strategies focused on reputation and quality to increase sales in this particular group.  相似文献   
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After introducing remarks on the meaning of the ethology of farm animals about the evaluation of housing systems the own examinations about piglets in the rearing period and about housing systems of rabbits held in groups respectively will be demonstrated. By these examinations choice experiments have proved true. For estimating and evaluating the ethological experimental results the concept of the meeting of requirements and avoidance of damage is an important point. The animals requirement can be found out in reference systems. Those investigated results are used as guiding-line for the evaluation of the dates found under practical conditions. The merits of Tschanz concerning the ethology of farm animals will be appreciated.  相似文献   
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Landscape Ecology - Large near-natural rivers have become rare in Europe, a fact reflected in the high conservation status of many riverine ecosystems. While the Balkan still harbors several intact...  相似文献   
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