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21.
本文评述了小类作赤霉病,与该病有关的病原物有17种,这些病原物发生在世界在部分谷类作物种植最常见的禾谷镰刀菌、黄色镰刀菌、燕麦镰刀菌梨孢镰刀菌、和雪腐镰刀菌。该病发生在湿气气候条件下,在此条件下谷物产量损失和毒物聚集显著。作物残体、替换寄主、以及禾谷类作物的镰刀菌菌腐和根腐是该病的可能接种体来源。 相似文献
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库布齐沙漠中段沙化土地植被状况及治理程度研究 总被引:1,自引:0,他引:1
本研究以库布齐沙漠中段为研究区域,以2003年、2008年和2014年三期遥感影像为信息源,以三期沙化土地监测数据为基础,采用地表实测与遥感技术相结合的方法对研究区十多年来沙化土地植被状况时空动态变化特征进行客观、科学地研究评价,同时对研究区沙化土地的治理程度及变化情况做出分析研究,指出土地植被状况及治理程度两者之间的关系,为今后该区域的治理提供科学的参考依据。 相似文献
23.
Manzke T Guenther U Ponimaskin EG Haller M Dutschmann M Schwarzacher S Richter DW 《Science (New York, N.Y.)》2003,301(5630):226-229
Opiates are widely used analgesics in anesthesiology, but they have serious adverse effects such as depression of breathing. This is caused by direct inhibition of rhythm-generating respiratory neurons in the Pre-Boetzinger complex (PBC) of the brainstem. We report that serotonin 4(a) [5-HT4(a)] receptors are strongly expressed in respiratory PBC neurons and that their selective activation protects spontaneous respiratory activity. Treatment of rats with a 5-HT4 receptor-specific agonist overcame fentanyl-induced respiratory depression and reestablished stable respiratory rhythm without loss of fentanyl's analgesic effect. These findings imply the prospect of a fine-tuned recovery from opioid-induced respiratory depression, through adjustment of intracellular adenosine 3',5'-monophosphate levels through the convergent signaling pathways in neurons. 相似文献
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A study was conducted on foothills rangeland to determine whether grazing patterns differed among cow breeds and to determine whether there was a relationship between individual grazing patterns and performance of beef cows. Hereford (HH), Tarentaise (TT), 3/4 Hereford x 1/4 Tarentaise (3H1T), 1/2 Hereford x 1/2 Tarentaise (HT), and 1/4 Hereford x 3/4 Tarentaise (1H3T) cows were observed during the summers of 1997 (n = 183) and 1998 (n = 159). Locations of individual cows were recorded two to three times per week during 1.5- to 2.5-h periods in the morning by observers on horseback. Statistical models included cow breed, age, and nursing status. Data from each year were analyzed separately. During 1997 and 1998, nonlactating cows were located at greater (P < 0.05) vertical distances from water than lactating cows. In 1998, nonlactating cows used steeper (P < 0.05) slopes than lactating cows. However, nonlactating cows did not travel as far horizontally from water (P < 0.05) as lactating cows in 1997. Younger cows (3 yr) traveled further (P < 0.05) from water both vertically and horizontally than older cows (5+ yr) in 1997, but not during 1998. Tarentaise and 1H3T cows were observed at greater (P < 0.05) vertical distances from water than HH cows during both years of the study. During 1998, TT and 1H3T cows used steeper (P < 0.05) slopes than HH cows. Using residual correlations, there were no consistent relationships between topographic aspects of individual grazing locations and cow weight, height, and body condition score. In 1997, cows with earlier calving dates and correspondingly heavier calf weaning weights used areas that had greater vertical distances to water; however, in 1998 there were no relationships (P > 0.05) of calving date and weaning weight with cow location. During both years, pregnant and nonpregnant cows used terrain similarly (P > 0.05), which suggests that cow reproductive performance was not related to terrain use. Grazing patterns in foothills rangeland varied among cow breeds. Performance of cows that used more rugged topography was similar to cows using gentler terrain. 相似文献
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Belov K Harrison GA Miller RD Cooper DW 《Veterinary immunology and immunopathology》2001,78(3-4):317-324
Two full length cDNA sequences encoding the kappa light chain of the Australian marsupial, Trichosurus vulpecula, the brushtail possum, were isolated from a mesenteric lymph node cDNA library. The constant regions (Ckappa) of the two light chains were identical, but the variable (Vkappa) and joining (Jkappa) regions were different. At the amino acid level, possum Ckappa was most similar to Ckappa of an American marsupial, Monodelphis domestica (75%), with similarity to eutherian Ckappa ranging from 47 to 63%. The availability of molecular data will enable the development of immunological reagents for studying immune responses and disease in marsupials, thereby aiding conservation strategies and veterinary medicine. 相似文献
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Diamond DW Besso J Boudrieau RJ 《Journal of the American Animal Hospital Association》1999,35(2):147-153
Medical records of 20 dogs with 23 shearing injuries of the tarsus leading to joint instability were reviewed. A transarticular external skeletal fixation device or prosthetic ligament was used to stabilize the joints. The most common complications were fixator failure and implant infection. The median times for wound healing and maximal joint function were 10 and 12 weeks, respectively. Clinical outcome was excellent in 22%, good in 56%, and poor in 22%. Comparison of the two stabilization methods showed no statistically significant differences in healing time, time to regain function, or clinical outcome. 相似文献
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AIM: To determine the effect of calcium supplementation of dairy cattle after calving on serum concentrations of calcium, magnesium, and phosphorous after calving, and on reproductive and productive performance in the following lactation. METHODS: This was a double-blind randomised clinical trial using 356 dairy cows of parity 3 or greater from six seasonally calving commercial dairy herds. Cows were randomly assigned to a treatment and control group. The treatment group received two doses of 380 ml of calcium chloride in oil (49 g of elemental calcium); the first dose was given as soon as practical after calving and the second 12 hours later. Control cows received 380 ml of a placebo using the same treatment regime. Treatment and control cows had blood samples taken during the first 7 days after calving to determine serum calcium, magnesium and phosphorous levels. Treatment and control cows were monitored throughout the lactation to measure production and reproductive performance. RESULTS: Treatment had no effect on PSM to first service intervals. Treatment significantly reduced PSM to conception intervals in only one of the four herds with data available for analysis (p = 0.09). There was no difference between treatment groups for adjusted corrected milk yield calculated from the first herd test milk yield (p = 0.93) or 305-day milk solids production (p = 0.19). CONCLUSION: Further studies are required to identify reasons for the between-herd effectiveness of calcium chloride treatment in improving fertility. 相似文献
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