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1.
国内生态恢复研究进展   总被引:1,自引:0,他引:1  
本文介绍了生态恢复的研究进展,从生态恢复的定义、退化生态系统的指标等方面进行阐述,重点对国内在恢复生态学方面的进展做了介绍.对当前的人工草地、草地农业的研究情况做了一些概述.  相似文献   

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国内生态恢复研究进展   总被引:10,自引:1,他引:9  
本文介绍了生态恢复的研究进展,从生态恢复的定义、退化生态系统的指标等方面进行阐述,重点对国内在恢复生态学方面的进展做了介绍。对当前的人工草地、草地农业的研究情况做了一些概述。  相似文献   

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This paper presents the main trends in the activity of European veterinary pathologists in the context of their oral presentations (plenary lectures and short presentations) and posters provided during annual meetings of the European Society of Veterinary Pathology (ESVP), in the decade 1997-2006. It was found that the issue that was most often brought up in the meetings was organ pathology (566 presentations). Infectious and parasitical diseases were only slightly less frequent (548 presentations). Oncology was another common issue (404 presentations). During this decade, 52 plenary lectures were presented, 765 oral presentations and 1 072 posters. Altogether, 1 889 presentations were made, which is between 127 and 238 per year. Research by Polish scientists accounted for 3.16% of all presentations. Additionally, the subject matter discussed at the annual meetings is analysed, and the trends in the development of veterinary diagnostic pathology and broad pathology education are indicated. It is shown that veterinary pathology enhances knowledge in the field of veterinary medicine by fulfilling a cognitive and diagnostic role.  相似文献   

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Progesterone levels in peripheral blood of dogs were analysed during the cycle in which hysterectomy (n = 5) or sham surgery (n = 3) was performed as well as during the cycle of dogs (n = 5) hysterectomized at least one year prior to this study; the data were compared with the findings in control dogs (n = 3). The averages of the duration of the luteal period observed in the three experimental groups were not significantly different from those of control dogs. Immediately after surgery, the progesterone level decreased from 25 to 50% of the presurgical level, but returned to presurgical level in about four days. Prolactin levels were elevated for about 30 h after surgery. Nevertheless, the averages of the mean prolactin levels for each animal during the luteal period of the experimental groups were not significantly different from those of control dogs. It is concluded that in the dog, the uterus is not involved in the lifespan of the cyclic corpus luteum.  相似文献   

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To find possible associations between antinuclear antibody (ANA) pattern, ANA titer, and certain clinical changes and clinical laboratory test results in dogs, the veterinary medical records of 111 ANA-positive and 126 ANA-negative dogs were examined. Variables could not be found that had significant associations with ANA pattern (unlike the results in persons), because of the predominance of 2 patterns. A log-linear model for ANA titer adequately fit the observed frequency and included 2-way interactions between titer and polyarthritis, titer and hematologic disorders, and polyarthritis and lymphadenopathy.  相似文献   

6.
In a 4-year period nine dogs have been met in which there was incomplete growth of the radius. The condition was unilateral in eight dogs and bilateral in one. Two were littermates. The defect is due to premature cessation of growth of the distal growth plate of the radius but the cause of this is not precisely known. It is recognized by characteristic radiographic changes in radius length, elbow joint space and premature closure of the distal growth plate of the radius. A method of surgical treatment has been devised and has proved beneficial in five dogs. Zusammenfassung. In einer Vierjahresperiode wurden neun Hunde beobachtet, bei denen ein unvollständiges Wachstum des Radius vorlag. Bei acht Hunden war der Zustand nur auf einer Seite zu finden, bei einem Hund auf beiden Seiten. Zwei der Hunde gehörten zum gleichen Wurf. Der Mangel ist auf verfrühte Wachstumseinstellung der distalen Wachstumsplatte des Radius zurückzuführen, jedoch ist die Ursache davon nicht genau bekannt. Er wird an charakteristischen radiographischen Veränderungen der Radiuslänge, des Ellbogengelenkzwischenraums und vorzeitigem Abschluss der distalen Wachstumsplatte des Radius erkannt. Es wurde eine chirurgische Behandlungsmethode entwickelt, die sich bei fünf Hunden als nutzlich erwies. Résumé. Au cows d'une période de 4 ans on a observé 9 cas de croissance incomplète du radius chez des chiens; l'anomalie était unilatérale dans 8 cas et bilatérale dans un cas; deux chiens appartenaient à la même portée. L'anomalie est due à l'arrêt prématuré de croissance de la plaque de croissance distale du radius, mais la cause n'en est pas encore connue d'une manière précise. Le diagnostic se fait par les signes radiologiques caractéristiques, modifications de la longueur du radius, de l'articulation du coude et soudure prématurée de la plaque de croissance du radius. On a élaboré une méthode de traitement chirurgical, qui s'est montrée favorable chez 5 chiens.  相似文献   

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Echinococcus granulosus (E. granulosus) infection was studied in 151 dogs in two regions of Morocco: 68 dogs in the northwest (Loukkos) and 83 dogs in the southwest (Tiznit). The mean prevalence rates of echinococcosis in dogs were 58.82% (46.23-70.63%) in Loukkos and 55.42% (44.10-66.34%) in Tiznit and the mean abundances of E. granulosus per dog were 75 (59-93) and 547 (504-595), respectively. The mean abundance of E. granulosus in dogs was fitted to a negative binomial distribution by the maximum likelihood techniques to define parameters. E. granulosus was aggregated in dogs in the two regions. The prevalence of infection and the abundance of E. granulosus in dogs were fitted to mathematical models in order to determine if the parasite population is partly regulated by definitive host immunity. The best fit was obtained with the models assuming the presence of immunity. The mean time of exposure to infection was similar in the two regions and ranged from 8 months to about 2 years. The infection pressures (number of E. granulosus) obtained per dog each year were 65 (8-294) in Loukkos and 476 (316-886) in Tiznit. The proportion of dogs susceptible to infection was still high along the life of the dogs in Loukkos, while it was not different from zero in old dogs of Tiznit.  相似文献   

12.
宋代,对士大夫来说这一可遇而不可求的特殊历史时期,成就了他们独特的人格结构和精神世界。他们对历史人物的看法尤异于前人,其中对管仲形象的接受就发生了颠覆性的变化。而宋人重新解读管仲的立足点也是宋代《史记》评论中普遍倾向的批评视角。  相似文献   

13.
大肠杆菌病在许多地区已经成为发病率最高的疾病之一,严重损害了养禽生产的效益。由于该病经常随饲养条件的变化而频繁发生,且病原菌对许多化学药物产生了较强的耐药性,使得生产中对该病的防治越来越困难。我们在禽病防治实践中,应用中兽医辩证论治理论,经反复筛选,拟定了一个中药组方-鸡痢灵用于防治鸡的大肠杆菌病,取得了较好的效果。  相似文献   

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The changes in the structure of nuclei and nucleoli are good markers of the changes in the activity of epithelium cells of oviducts in cows during the sexual cycle. They are manifested by the changes in the proportion of condensed chromatin and interchromatin. In the secretory as well as ciliary cells, the maximum proportion of interchromatin is recorded in pro-oestrus and oestrus, whereas in metoestrus it is the proportion of condensed chromatin that increases. Metoestrus is characterized by the segregation of nucleoli and by the formation of ring-like nucleoli which partially persist also in dioestrus and in some cells throughout the cycle. Invaginations of the nuclear membrane (which are levelled off later) occur on many nuclei at the end of metoestrus and in dioestrus. Single nuclear bodies occur in the nuclei and the frequency of the the occurrence of interchromatin granules changes. Dilation of perinuclear spaces can be observed in the secretory cells, mainly in the period of oestrus.  相似文献   

17.
现在研究普遍认为活性氧自由基是导致胚胎体外发育阻滞的主要原因。本文主要综述了不同抗氧化剂对牛胚胎体外发育的影响,并分析其作用机制。  相似文献   

18.
Tracer experiments with [5-3H]-uridine have shown that the amount of poly A+-RNA in mouse brain is reduced by about 50% in the clinical stage of scrapie. This reduction is largely confined to poly A+-RNA in the nuclear fraction of scrapie-brain and it is suggested that the non-messenger species of poly A+-RNA are mainly affected. A 50% reduction in the amount of poly A+-RNA can be detected in scrapie-mouse brain as early as 3 weeks after intracerebral or intraperitoneal infection with large doses of the agent. This is the earliest biochemical change known in mouse scrapie. Early changes in poly A+-RNA have also been found in livers and spleens of scrapie-mice, but the spleen changes are more complicated with an early elevation and a later depression. Attempts have been made to study the size distribution of poly A+-RNA molecules involved in these changes. The possible significance of these findings in the pathogenesis of mouse scrapie is discussed.  相似文献   

19.
Physiological changes in the concentrations of biotin in the serum and milk and in the physical properties of the claw horn were examined in Holstein cows. A lower concentration of biotin in the serum and a higher concentration of biotin in milk were found during early and late lactation and during the dry period, and a significant (p<0.05) inverse correlation was found between serum and milk biotin concentrations. A high moisture content and a low level of hardness of the claw horn were found during mid-lactation. Our results indicate that change in the serum biotin concentration probably results from the loss of biotin in the milk of cows during each stage of lactation and also confirm that the moisture content and hardness of the claw horn undergo physiological changes.  相似文献   

20.
The participation of central cholecystokinin-8 (CCK-8) receptors in the modulatory effect of D-Ala2, N-Me-Phe4, Gly5-ol enkephalin (DAGO), a selective mu-opioid receptor agonist, on the spike burst activity of the gastrointestinal tract (rumen, reticulum, antrum, duodenum, colon and caecum) in sheep was investigated. DAGO was infused intracerebroventricularly (i.c.v.) at doses of 0.1-1 microg/kg body weight (BW). It was shown that DAGO significantly inhibited myoelectrical activity of the wall of the forestomachs, abomasum and colon but stimulated this activity in the duodenum (rate of myoelectrical migrant complex-MMC). The effects of DAGO were prevented by CCK-8 antagonists (L-364.718 and L-365.260) previously infused at doses of 5-20 microg/kg BW. The results of this present study indicate that central receptors of CCK-8 participated in the modulatory action of an opioid on myoelectrical activity of the gastrointestinal tract in sheep. Furthermore, this result suggests that CCK-8 is released in response to mu-receptor stimulation, because CCK-8 antagonists (L-364.718 and L-365.260) prevented the modulatory action of DAGO on the gastrointestinal motility in sheep.  相似文献   

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