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排序方式: 共有102条查询结果,搜索用时 31 毫秒
31.
Grubb TL Högman M Edner A Frendin JH Heinonen E Malavasi LM Frostell CG Ryden A Alving K Nyman GC 《American journal of veterinary research》2008,69(3):423-430
OBJECTIVE: To assess physiologic responses and plasma endothelin (ET)-1 concentrations associated with abrupt cessation of nitric oxide (NO) inhalation in isoflurane-anesthetized horses. ANIMALS: 6 healthy adult Standardbreds. PROCEDURES: Horses were anesthetized with isoflurane in oxygen and placed in dorsal recumbency. Nitric oxide was pulsed into the respiratory tract for 2.5 hours, and then administration was abruptly discontinued. Just prior to commencement and at cessation of NO administration, and at intervals during a 30-minute period following cessation of NO inhalation, several variables including PaO(2), mean pulmonary artery pressure, venous admixture or pulmonary shunt fraction (Qs/Qt), and plasma ET-1 concentration were recorded or calculated. RESULTS: After cessation of NO inhalation, PaO(2) decreased slowly but significantly (172.7 +/- 29.8 mm Hg to 84.6 +/- 10.9 mm Hg) and Qs/Qt increased slowly but significantly (25 +/- 2% to 40 +/- 3%) over a 30-minute period. Mean pulmonary artery pressure increased slightly (14.0 +/- 1.3 mm Hg to 16.8 +/- 1 mm Hg) over the same time period. No change in serum ET-1 concentration was detected, and other variables did not change or underwent minor changes. CONCLUSIONS AND CLINICAL RELEVANCE: The improvement in arterial oxygenation during pulsed inhalation of NO to healthy isoflurane-anesthetized horses decreased only gradually during a 30-minute period following cessation of NO inhalation, and serum ET-1 concentration was not affected. Because a rapid rebound response did not develop, inhalation of NO might be clinically useful in the treatment of hypoxemia in healthy isoflurane-anesthetized horses. 相似文献
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33.
The concentrations of Gs137 in meat from lamb in the falls of 1964 and 1965 and in meat from sheep in the fall of 1965 have been determined. The results are given and discussed with regard to the geographical variations, the decreasing concentrations from 1964 to 1965 and to the different concentrations in lamb and sheep. 相似文献
34.
Kjell Nilsson Ulrika kerlund Cecil C. Konijnendijk Alexander Alekseev Ole H. Caspersen Susanne Guldager Evgeny Kuznetsov Alexander Mezenko Andrey Selikhovkin 《Urban Forestry & Urban Greening》2007,6(2):93-101
Recent years have seen the introduction of the concept of urban greening, defined as embracing the planning and management of all urban vegetation to create or add values to the local community. Green-space development has become recognised by international agencies and donors as important tool in improving the quality of urban livelihoods and urban environment. This paper evaluates an example of an urban greening aid project, carried out by Danish and Russian partners in the city of St. Petersburg, Russia. The project aimed to contribute to conservation and development of the cultural–historical, social and ecological values of St. Petersburg's urban green areas by implementing a structured, socially inclusive, well-informed planning and management approach. The project had three main components: (1) the development of a GIS-based information system to assist green-space planning and management; (2) on-site improvements in selected green areas and (3) awareness raising and public involvement activities. Ex post evaluation of the project showed that in spite of the limits of time and resources, important results were achieved. A more strategic approach to urban green-space planning and management, as promoted by urban greening, was adapted by some of the Russian project partners. Achievements also included notable physical improvements to one park. But the main project impacts were improved communication and collaboration between the local park department and local academia, as well as expertise developed in running a complex urban greening project. The project failed, however, in its public involvement ambitions.Moreover, the project should have facilitated discussion on some of the current premises of urban green-space planning and management in St. Petersburg, which insufficiently consider changing values and public preferences related to green spaces. 相似文献
35.
The same computerized recording system as described in Part I of this publication (Flesjå & Ulvesœter 1979) was applied to sows slaughtered at Sentralslakteriet, Forus, Stavanger.In the three-year period 1975–1977 a total of 10,051 apparently healthy sows were brought to the abattoir. About 17 % of the carcasses had one or more pathological lesions. Of the total number of lesions 89 % were confined to 18 of the available 57 disease codes. Pyaemia and abscess/-es occurred at a rate of 1.5 and 3.2 %, respectively. This comprised 21 % of all registered lesions. Scabies and numerous white liver spots came to another 21 %, occurring in 3.3 and 1.5 % of the animals, respectively. About 15 % were chest lesions, of which pleurisy was diagnosed in 1.4 % and pericarditis in 1.3 % of the slaughtered sows. Other lesions recorded in 1 % or more included perihepatitis and other non-parasitic liver lesions, arthritis and decubitus.Only code 31 — numerous white spots in the liver showed a convincing seasonal variation.Significantly higher frequencies of pyaemia and abscess/-es occurred in culled sows than in baconers, but no such difference could be found for peritonitis, polyarthritis and arthritis. For all other commonly observed lesions significantly lower frequencies were seen in sows compared to baconers.Various theories are suggested to explain the observed difference in the distribution of lesions between baconers and sows. 相似文献
36.
Ultrastructural changes of the different spermatid organelles have been studied in order to establish a basis for subdivision of blue fox spermateleosis. Testicular tissue from 9 sexually mature animals was obtained within the breeding season (March—April), As a result of electron microscopical observations, ten distinct stages of spermatid differentiation could be defined. 相似文献
37.
Serum samples from 4339 wild cervids collected in Norway were tested for antibodies against Toxoplasma gondii using the direct agglutination test. The association between seroprevalence and species, sex, age, and geographic region was investigated. Positive titers (> or =1:40) were found in 33.9% of 760 roe deer (Capreolus capreolus); 12.6% of 2142 moose (Alces alces); 7.7% of 571 red deer (Cervus elaphus); and 1.0% of 866 reindeer (Rangifer tarandus). The seroprevalences were significantly different between the species. There was a significant increase in prevalence with age in roe deer, moose, and red deer, except from yearling to adult in red deer. A significant age-sex interaction was found in moose, and the effect of age was most distinct for females. No association between seropositive animals and sex was found for roe deer and red deer. There were significant differences in prevalence between geographic regions in roe deer and male moose. A widespread exposure to T. gondii in Norwegian cervids is documented, and meat from Norwegian cervids, particularly roe deer, should be regarded a potential source of infection for humans. 相似文献
38.
Jacek Hilszczański Heloise Gibb Ola Atlegrim Roger B. Pettersson Kjell Danell 《Biological conservation》2005,126(4):456-464
The habitat requirements and effects of forest management on insects belonging to higher trophic levels are relatively unknown in forest ecosystems. We tested the effect of forest successional stage and dead wood characteristics on the saproxylic parasitoid (Hymenoptera, Ichneumonoidea) assemblage in boreal spruce-dominated forests in northern Sweden. Within each of nine areas, we selected three sites with different management histories: (1) a clear-cut (2) a mature managed forest and (3) an old-growth forest. Parasitoids were collected in 2003 using eclector traps mounted on fresh logs, which were either untreated (control), burned, inoculated with fungi, or naturally shaded, and on artificially-created snags.Both forest type and dead wood characteristics had a significant effect on parasitoid assemblages. Grouped idiobionts and some species, such as Bracon obscurator and Ontsira antica, preferred clear-cuts, while others, such as Cosmophorus regius (Hym., Braconidae) and other koinobionts, were associated with older successional forest stages. No single dead wood substrate was sufficient to support the entire community of parasitoids in any forest type, even when the regular host was present. In particular, snags hosted a different assemblage of species from other types of dead wood, with parasitoids of Tetropium spp. such as Rhimphoctona spp. (Hym., Ichneumonidae) and Helconidea dentator (Hym., Braconidae) being abundant. These results indicate that a diversity of dead wood habitats is necessary to support complete assemblages of beetle-associated parasitoids from early successional stages of dead wood and that parasitoids may be more sensitive to habitat change than their hosts. 相似文献
39.
Acidified surface waters often show elevated aluminium (Al) levels, detrimental to fish and some invertebrates. Whether Al can accumulate in benthic invertebrates, with time and/or along the food chain, is not clear. To test this, benthic invertebrates, representing different functional feeding groups, were collected in spring from streams, with different acidity and Al concentrations. Weight-specific Al content was determined with an AAS. At localities with pH ≈ 4, high Al contents (≈ 1 mg inorg-Al g?1 af dw) were found in shredders and/or deposit feeders (Asellus aquaticus, Nemoura sp., and limnephilids), while the predator Isoperla grammatica contained only ≈ 0.3 mg Al g?1, and the “filtering predator” Plectrocnemia conspersa almost no Al. Also at pH ≈ 6 Nemoura sp. and limnephilids showed significantly higher Al contents than did the predators Isoperla grammatica and Rhyacophila nubila, Al concentrations of the animals were often higher at pH 4 than at pH 6. Thus, no evidence of any food chain accumulation (or biomagnification) of Al could be validated. Accordingly, this study gives no support that the high concentrations of Al in fish and birds are due to their feeding on benthic invertebrates at low pH conditions. It was also found that animals that inhabit and/or consume benthic detritus as food contain highest Al levels. 相似文献
40.
Modelling the advection and diffusion of eggs and larvae of Greenland halibut (Reinhardtius hippoglossoides) in the north-east Arctic 总被引:1,自引:0,他引:1
Bjørn Ådlandsvik Agnes C. Gundersen Kjell H. Nedreaas Anne Stene Ole T. Albert 《Fisheries Oceanography》2004,13(6):403-415
Since the late 1980s there has been considerable uncertainty in recruitment levels of the north‐east Arctic stock of Greenland halibut (Reinhardtius hippoglossoides). The abundance of several year classes, originally considered very low at 0–3 yr age, appeared higher than expected at the age of 6+. This may be due to poor targeting of recruitment surveys of the younger year classes. The present work considers the transport and dispersion of eggs and larvae of Greenland halibut by numerical modelling in order to predict the locations of the initial recruitment grounds. Current fields from a 3D baroclinic hydrodynamic model are fed into a Lagrangian particle‐tracking model developed for the Barents Sea area. The particles are released into the current at the spawning field along the shelf slope from Lofoten to Bear Island (69–75°N). Vertically, the particles can follow a predefined depth‐by‐age curve or be kept at a fixed depth. This model system is used for different years to examine changes in the drift pattern. The results indicate that spawning location, transport depth and inflowing activity to the Barents Sea are important factors influencing the distribution of juveniles. 相似文献