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991.
4-Aminopyridine (4-AP) is the only pesticide that can be legally used in the US to reduce bird damage in ripening grain fields. Birds that consume grain baits treated with 4-AP (‘Avitrol’ FC-99®) exhibit erratic behavior and emit vocalizations that presumably scare away the rest of the flock. Yet the behavior of 4-A Pintoxicated birds has not been documented, and we do not know how other birds react when observing these intoxicated birds or what these observers learn from their experience. Hence, we examined the behavior of 15 4-A Pintoxicated red-winged blackbirds (Agelaius phoeniceus (L.)) and found that initial signs of intoxication occurred 12.5 min after consumption of the bait, with death following 16.3 min later. During this 16-min intoxication period, birds gradually lost muscular control, making their movements and vocalizations weaker until hardly perceptible. Other captive red-winged blackbirds (‘observers’) gave more alarm calls while witnessing a 4-A P-intoxicated bird in one room of their cage (treatment period) than they did during the pre-treatment period. Immediately after the intoxicated bird died and was removed from the room, the observers' behaviour returned to pre-treatment levels. Broadcasting calls of an intoxicated bird or the placement of an untreated bird in one of the rooms had little effect on the observers' behavior. In another experiment, the placement of a 4-A Pintoxicated or untreated red-winged blackbird or the broadcast of calls of an intoxicated bird at a feed station did not affect the number of free-ranging conspecifics feeding, within sight of, or vocalizing at, these feeder stations. These results suggest that red-winged blackbirds learn little from witnessing a distressed conspecific.  相似文献   
992.
Two mature breeding stallions were evaluated because of specific ejaculatory dysfunction, and each was found to have aortic-iliac thrombosis occluding 60 to 70% of the aortic lumen. In each case, the stallion had strong libido, normal mounting, and vigorous initial thrusting. With continued exertion, thrusting became weak and dismount was awkward. Treatment aimed at maximizing sexual arousal before mounting and reducing hind limb pain and exertion during breeding allowed these stallions to continue breeding. A program of gradually increasing daily exercise also was associated with improved breeding performance during subsequent breeding seasons. In cases of specific ejaculatory dysfunction, aortic-iliac disease should be included among the differential diagnoses.  相似文献   
993.
The number of neurons in the coeliacomesenteric ganglia and the myenteric and submucosal plexuses of the jejunum, ileum and small colon, and the pathological changes induced in them, were studied in various types of equine dysautonomia. In all forms of dysautonomia, severe and extensive neuron loss and damage occurred in the ileum. In acute and subacute dysautonomia, jejunal neuron loss and damage were severe, but in chronic cases significantly less loss or damage occurred. The damage followed the same pattern in the small colon but it was always less obvious than in the jejunum. The distribution of the damage was uniform within a segment of the intestine. In fatal cases of dysautonomia, the clinical severity and duration of illness seems, in most instances, to be related to the amount of neuronal disruption occurring in the jejunum. Severe disruption results in acute/subacute dysautonomia, while milder damage leads to the chronic form.No case of dysautonomia was encountered in which enteric neuron loss and damage occurred without significant neuronal disruption also occurring in the coeliacomesenteric ganglia.Ileal neuronal damage and loss are not invariably worse than that in the jejunum, and the possible reasons for this, together with the relationship between neuronal damage and possible causes of dysautonomia, are discussed.Abbreviations H&E haematoxylin and eosin Deceased. Formerly of the Moredun Research Institute, 408 Gilmerton Road, Edinburgh, EH17 7JH, UK  相似文献   
994.
Three oat (Avena saliva L.) populations (i.e., lines of descent), high grain yield (HG), high protein content (HP), and high protein yield per se (HGP), each developed by three cycles of S, recurrent selection, were evaluated for the effect of selection for groat-protein yield upon other agronomic traits. Selections making up the HG line of descent had high protein yield primarily due to high grain yield, and those selected for HP had high protein yield due to both high protein content and high grain yield. Selection in HGP was on the basis of protein yield per se. Selection caused increases in bundle weight, harvest index, vegetative growth rate, and seed number in all lines of descent. Heading date, plant height, and seed weight were unaffected, whereas groat percentage and test weight were decreased in HP and HGP. Heritabilities were high for heading date, plant height, test weight, and seed weight, moderate for harvest index and bundle weight, and low for groat percentage. Genetic variability generally declined from CO to C3 for all traits. Groat-protein yield and amount of protein per groat increased in all lines of descent. In HG, the increase in groat weight was due primarily to increases in the nonprotein fraction, with groat-protein content actually decreasing. In HGP, groat weight increased due to increases in protein and nonprotein fractions, and groat protein content remained constant. In HP, groat weight and amount of nonprotein per groat decreased, thus increasing groat-protein content. Three cycles of recurrent selection resulted in oat lines with groat-protein yields significantly higher than the highest lines from CO. Utilization of index selection may be desirable to obtain populations of greater breeding value.  相似文献   
995.
An eight-year-old beaver lost one of its upper central incisors through unknown causes. As the anterior teeth of this species continually erupt in a similar manner to rodents' teeth, the unopposed lower incisor had over-erupted perforating the palate and entered the nasal cavity. The height of the lower incisor tooth was reduced and a cobaltchromium alloy bridge was constructed which was attached to the remaining upper incisor. The occlusal surface of the bridge was of sufficient width that both incisors could contact it. It was cemented into place with composite resin cement and cross-pinned through the labial surface of the metal into the tooth substance. It is unknown how such treatment will affect the biological processes underlying the continually erupting incisor and the animal is being monitored for any adverse effects.  相似文献   
996.
Marketing to veterinarians is the process of synchronizing the business aspects of his or her goods and services so that they are understood and desired by animal owners. The basic components of a successful marketing program are in four categories: the individual, the situation, the needs, and the implementation. Each category is important and all are interrelated; however, the implementation of a program should not begin until a self-analysis has been done and the situation and its needs are thoroughly researched. Programs that have been used by successful practitioners can be copied. No program can be effective unless the economic status of the client's enterprise is known and understood.  相似文献   
997.
番茄斑萎病毒(TSWV)广州分离物生物学特性研究   总被引:1,自引:0,他引:1  
 1984年南方花生病害调查,发现由番茄斑萎病毒(TSWV)引起的新病害。  相似文献   
998.
Multiplication of the rye-specific and barley-specific pathovars secalis and translucens, respectively, of Xanthomonas campestris (earlier named Xanthomonas translucens f. sp. cerealis) was determined in two rye and two barley cultivars. Fresh bacterial cultures were suspended in boiled tap water, adjusted to about 3 × 107 cfu ml?1 and infiltrated into the mesophyll of young leaves. In the compatible combinations, a generation time of 1.7–2.1 h was determined. Significantly higher multiplication rates than in incompatible combinations were not observed before 3 or 4 days after inoculation. At this time, the first small water-soaked areas appeared. Bacteria multiplied up to the seventh day after inoculation, reaching a maximum of at least 109 cells per cm2, the same time at which the water-soaked areas had reached their maximum size. Thus, the rate of bacterial multiplication paralleled with the development of the water-soaked areas. In the incompatible combinations, nearly the same generation times were detected during the exponential growth phase. However, water-soaked areas did not appear, and the final bacterial concentration ranged from 1:1000 to 1:100 of that determined in compatible combinations. A distinct early lag phase, characterized by a decrease of the bacterial population down to 1:100 of the starting concentration, was detected in all cases.  相似文献   
999.
1000.
对天津市设施农业的现状分析及展望   总被引:1,自引:0,他引:1  
设施农业又被称为工厂化农业,具有强大的生命力和广阔的发展前景,是农业可持续发展的重要内容之一.同时也是加速我国农业工程化进程,成为促进我国传统农业向现代化农业发展的必由之路。  相似文献   
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