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排序方式: 共有85条查询结果,搜索用时 125 毫秒
1.
Kim Birnie‐Gauvin Lasse Birch Hjrup Theis Kragh Lene Jacobsen Kim Aarestrup 《Ecology of Freshwater Fish》2019,28(3):376-384
Pike (Esox lucius) occupy coastal streams and rivers of the Baltic Sea, where they attain large sizes (>5 kg). These large sizes are perhaps due to the fact that they can tolerate relatively high salinities and can thus forage in the nearby more productive brackish environments. In an attempt to quantify the extent to which pike utilise brackish environments, and to provide some insight into the underlying causes for brackish water migrations, we tagged 30 pike from a western Baltic river with acoustic transmitters and were able to track 21 individuals for 1 year. Based on experienced from local anglers, this population was assumed to be brackish in nature, where individuals underwent freshwater migrations to spawn. Our findings however suggest that the smallest and most active individuals make short exits into brackish waters and do so on rare occasions. Our results further indicate that neither sex nor size is related to activity level. We suggest that these patterns reflect two distinct behaviours—active and passive—and that large pike can be supported by the food availability in the river, without the need to venture into coastal zones, thus defying the conventional view that Baltic pike are all brackish in nature. 相似文献
2.
Randomized placebo-controlled crossover studies were carried out in dogs to evaluate how two non-steroidal anti-inflammatory drugs (NSAID) might modulate an acute post-traumatic inflammatory reaction. Two "identical" surgical interventions were performed on the forelimbs of each animal with an interval of 28 days, to enable a paired comparison of the inflammatory signs and the wound/bone healing processes. At one operation 8 dogs received 300 mg phenylbutazone twice daily for 8 days starting on the day before surgery, and at the other operation matching placebo tablets were given. In a similar placebo-controlled trial another group of 8 dogs received 5 mg indomethacin twice daily. With phenylbutazone the post-operative swelling was not significantly reduced compared to placebo, but there was less pain and limping. With indomethacin the swelling was somewhat reduced, but there was no consistent difference to placebo in the pain and limping assessments. None of the drugs appeared to distinctly effect the wound or fracture healing, as evaluated by clinical inspection, comparison of radiographs and comparison of bone sections from the sites of surgery. It proved difficult to select an appropriate dosage of indomethacin due to its high potential to induce GI ulceration and bleeding in dogs. In this experimental surgical model with an acute inflammation, neither phenylbutazone nor indomethacin showed impressive anti-inflammatory or analgesic properties. In the same model paracetamol has proved to significantly and more efficiently, reduce both swelling and pain without any noticeable adverse effects, and appears to be a better alternative than the two presently tested NSAID. 相似文献
3.
I. J. Uhaa H. P. Riemann M. C. Thurmond C. E. Franti 《Veterinary research communications》1990,14(2):99-112
A seroepidemiological study on bluetongue virus (BTV) infection in California dairy cattle was conducted to estimate the prevalence and distribution by age and season of BTV group-reactive antibodies and to look for possible associations between the presence of antibodies and cattle age or breed and farm. Between December 1985 and March 1987, a sample of cattle was tested at approximately two-month intervals for BTV group-reactive antibodies using an enzyme-linked immunosorbent assay (ELISA). Data taken during the month of December 1986 were used to evaluate possible associations between a positive antibody test and certain intrinsic (age, breed) and extrinsic (farm) factors.Univariate and multivariate statistical analyses using the -square test for associations and multiple logistic regression, respectively, were carried out for possible associations between positive antibody tests to BTV and each factor of interest. The strengths of the associations were determined using estimates of the odds ratio.Of the 3774 serum samples tested, 238 (6.3%) were from calves, 1045 (27.6%) were from heifers and 2492 (66.0%) were from cows. Seroprevalence varied from nil in calves on two occasions to over 90% on several occasions in cows. Cows consistently had higher prevalence rates than heifers or calves across all test dates (p<0.05). The seroprevalence of BTV group-reactive antibodies also showed a seasonal fluctuation, with the highest rates occurring during the warmer months of the year. These highest prevalence rates coincided with heavy activity of the known vector of BTV, Culicoides spp. Breed and farm effects were not statistically significant (p>0.05). With the exception of one farm, all cattle were of the Holstein breed, which reduced confidence in assessing any breed effect in this study. Relative estimates of the sensitivity and specificity of BTV ELISA were 87% and 100% respectively, compared to the standard agar gel immunodiffusion (AGID) test.The observations support previous findings of seasonal distribution of BTV antibodies and suggest an age relationship, whereby older cattle are more likely to be positive to BTV group-reactive antibodies than younger cattle. 相似文献
4.
D E Behymer E L Biberstein H P Riemann C E Franti M Sawyer 《American journal of veterinary research》1975,36(6):781-784
The immune response and persistence of antibodies were investigated in dairy cattle vaccinated with formalin-inactivated phase (ph) I Coxiella burnetii vaccine agglutinating antibody geometric mean titer (GMT) of 193.2 at 1 month after vaccination compared to a GMT of 2.0 for nonvaccinated calves. The agglutinating antibodies gradually decreased in vaccinated cattle, but the GMT remained approximately 4 times higher than that for the nonvaccinated group for at least 20 months. Results of serotests at 2 months after revaccination indicated a rapid increase in the GMT to 177.0 with agglutinating titers between 1:64 and 1:512. 相似文献
5.
Coxiella burnetii infection (Q fever) 总被引:1,自引:0,他引:1
6.
A linear programming (LP) model was designed to evaluate trypanosomiasis control activities in south-western Ethiopia. The objectives included maximizing net benefits, utilization of unskilled labor, and resettlement of reclaimed land, and decreasing the prevalence of trypanosomiasis from 20% to less than 5% at the end of 5 years, subject to epidemiological, ecological and economic constraints. The model was a multiperiod specification with 127 equations and 81 activities for the project period of 5 years. The optimal solution required reclamation of 5221 km2 of tsetse infested land and used treatment of cattle at maximal levels. At the end of the project period, the prevalance decreased to 2% with net benefits of E$1.281 million. LP provided a potentially optimal means of resource allocation in the short run and a means of identifying those restrictive resources which could be vital to long range planning. 相似文献
7.
Riemann HP 《Journal of the American Veterinary Medical Association》2002,220(2):167; author reply 167
8.
Eva Andersson Sampath R. Kumar Jared Ackers Geir Lasse Taranger Sigurd Olav Stefansson John M. Trant 《Fish physiology and biochemistry》2003,28(1-4):411-411
Photoperiod and temperature modulated the seasonal pattern of ovarian gene expression of P450 aromatase, Follicle-Stimulating Hormone receptor and Luteinizing Hormone receptor in Atlantic salmon broodstock. 相似文献
9.
Release of mature sperm from the testis into seminal ducts of the gypsy moth exhibits a circadian rhythm. The rhythm of sperm release was shown to persist in vitro, in isolated complexes of testis and seminal ducts cultured in light-dark cycles or in constant darkness. The phase of the rhythm was also reset in vitro by exposure to shifted light-dark cycles. Therefore, the testis-seminal ducts complex from the gypsy moth is photosensitive and contains a circadian pacemaker, which controls the rhythm of sperm movement. This finding extends the range of structures in multicellular organisms that are known to contain circadian oscillators and provides a new model system in which circadian mechanisms may be studied. 相似文献
10.
Ben-Shem A Garreau de Loubresse N Melnikov S Jenner L Yusupova G Yusupov M 《Science (New York, N.Y.)》2011,334(6062):1524-1529
Ribosomes translate genetic information encoded by messenger RNA into proteins. Many aspects of translation and its regulation are specific to eukaryotes, whose ribosomes are much larger and intricate than their bacterial counterparts. We report the crystal structure of the 80S ribosome from the yeast Saccharomyces cerevisiae--including nearly all ribosomal RNA bases and protein side chains as well as an additional protein, Stm1--at a resolution of 3.0 angstroms. This atomic model reveals the architecture of eukaryote-specific elements and their interaction with the universally conserved core, and describes all eukaryote-specific bridges between the two ribosomal subunits. It forms the structural framework for the design and analysis of experiments that explore the eukaryotic translation apparatus and the evolutionary forces that shaped it. 相似文献