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291.
Gachohi John M. Kitala Phillip M. Ngumi Priscilla N. Skilton Rob A. 《Tropical animal health and production》2011,43(1):271-277
The objective of this study was to investigate the relationship between seroprevalence to Theileria parva infection in cattle and potential environmental and farm-level effects in 80 farms under traditional crop–livestock system
in Mbeere District, Kenya. A standardized questionnaire was used to collect the effects characteristics as related to T. parva infection epidemiology. Serum samples were collected from 440 cattle of all ages for detection of T. parva antibodies by the enzyme-linked immunosorbent assay technique. The association between the variables was assessed using a
generalized estimation equation logistic regression model. The overall T. parva seroprevalence, accounting for correlation of responses, was 19.3% (95% confidence interval (CI) 14%, 25%). Two variables,
“administrative division” and “presence of the vector tick on the farm”, were significantly associated with the T. parva seroresponse. Respectively, cattle from farms in Gachoka, Evurore, and Mwea divisions were (and their 95% CI) 1.3 (0.36,
4.8), 4.4 (1.2, 15.9), and 15.2 (4.9, 47.1) times more likely to be seropositive relative to those from Siakago Division (P = 0.000). Cattle from farms in which the vector tick was present were 2.9 (1.2, 6.7) times more likely to be seropositive
(P = 0.011). Results of this study suggested that both environmental and farm factors may be associated with T. parva infection epidemiology in Mbeere District. Under such circumstances, characterization of environmental suitability for the
vector tick and corresponding environment-specific farm management practices in the district is required both for improved
understanding of the disease and in planning disease control programs. 相似文献
292.
Backues K Clyde V Denver M Fiorello C Hilsenroth R Lamberski N Larson S Meehan T Murray M Ramer J Ramsay E Suedmeyer K Whiteside D;Executive Committee American Association of Zoo Veterinarians 《Journal of zoo and wildlife medicine》2011,42(1):176-192
These guidelines for veterinary medical care and veterinary hospitals are written to conform with the requirements of the Animal Welfare Act, which states that programs of disease prevention and parasite control, euthanasia, and adequate veterinary care shall be established and maintained under the supervision of a veterinarian. Ideally the zoo and aquarium should be providing the best possible veterinary medical care for the animals in their collections. Many of these animals are rare and endangered and the institutions should endeavor both to provide for the long term health and well being of these animals and to advance the field of non-domestic animal medicine. It is hoped that this publication will aid in this process. 相似文献
293.
对极粗质地的森林土壤一次施用500t/hm~2干污泥15年后的土壤剖面样品,分析了pH值、ECE、全N、P、K、S、Ca、Mg、Cd、Cu、Ni、Pb和Zn等,并同对照土进行比较。表层(0~17cm)中全N、P、S、CEC、Cd、Cu、Ni、Pb和Zn的含量明显高于对照区;由于这种风化不完全的土壤含K、Mg、Ca较丰富,处理区与对照区差异不大;土壤pH值处理区要低;Mg移到较深层次;Ni和Zn稍有移动;Pb、Cd、Cu、移至17~27cm,但未再向下层移动。 相似文献
294.
Tiago Leo Mingxun Wang Nathan Moss Ricardo da Silva Jon Sanders Sergey Nurk Alexey Gurevich Gregory Humphrey Raphael Reher Qiyun Zhu Pedro Belda-Ferre Evgenia Glukhov Syrena Whitner Kelsey L. Alexander Robert Rex Pavel Pevzner Pieter C. Dorrestein Rob Knight Nuno Bandeira William H. Gerwick Lena Gerwick 《Marine drugs》2021,19(1)
Microbial natural products are important for the understanding of microbial interactions, chemical defense and communication, and have also served as an inspirational source for numerous pharmaceutical drugs. Tropical marine cyanobacteria have been highlighted as a great source of new natural products, however, few reports have appeared wherein a multi-omics approach has been used to study their natural products potential (i.e., reports are often focused on an individual natural product and its biosynthesis). This study focuses on describing the natural product genetic potential as well as the expressed natural product molecules in benthic tropical cyanobacteria. We collected from several sites around the world and sequenced the genomes of 24 tropical filamentous marine cyanobacteria. The informatics program antiSMASH was used to annotate the major classes of gene clusters. BiG-SCAPE phylum-wide analysis revealed the most promising strains for natural product discovery among these cyanobacteria. LCMS/MS-based metabolomics highlighted the most abundant molecules and molecular classes among 10 of these marine cyanobacterial samples. We observed that despite many genes encoding for peptidic natural products, peptides were not as abundant as lipids and lipopeptides in the chemical extracts. Our results highlight a number of highly interesting biosynthetic gene clusters for genome mining among these cyanobacterial samples. 相似文献
295.
Effect of elevated carbon dioxide on growth and nitrogen fixation of two soybean cultivars in northern China 总被引:1,自引:0,他引:1
Shu Kee Lam Xingyu Hao Erda Lin Xue Han Rob Norton Arvin R. Mosier Saman Seneweera Deli Chen 《Biology and Fertility of Soils》2012,48(5):603-606
The effect of elevated carbon dioxide (CO2) concentration on symbiotic nitrogen fixation in soybean under open-air conditions has not been reported. Two soybean cultivars (Glycine max (L.) Merr. cv. Zhonghuang 13 and cv. Zhonghuang 35) were grown to maturity under ambient (415?±?16?μmol?mol?1) and elevated (550?±?17?μmol?mol?1) [CO2] at the free-air carbon dioxide enrichment experimental facility in northern China. Elevated [CO2] increased above- and below-ground biomass by 16–18% and 11–20%, respectively, but had no significant effect on the tissue C/N ratio at maturity. Elevated [CO2] increased the percentage of N derived from the atmosphere (%Ndfa, estimated by natural abundance) from 59% to 79% for Zhonghuang 13, and the amount of N fixed from 166 to 275?kg N ha?1, but had no significant effect on either parameter for Zhonghuang 35. These results suggest that variation in N2 fixation ability in response to elevated [CO2] should be used as key trait for selecting cultivars for future climate with respect to meeting the higher N demand driven by a carbon-rich atmosphere. 相似文献
296.
Luis Gaitero Stephanie Nykamp Rob Daniel Gabrielle Monteith 《Veterinary radiology & ultrasound》2013,54(2):133-138
Cranial thoracic intervertebral disc herniations have been reported to be rare in dogs due to the presence of the intercapital ligament, however some studies have proposed they may not be uncommon in German Shepherd dogs. The purpose of this retrospective study was to compare cranial thoracic intervertebral disc herniations in German Shepherd dogs and other large breed dogs (control group). Medical records at the Ontario Veterinary College were searched for German Shepherd dogs and other large breed dogs that had magnetic resonance imaging studies including the T1‐T9 region. For each dog and each disc space from T1‐T9, three variables (compression, disc degeneration, and herniation) were recorded and graded based on review of sagittal T2‐weighted images. Twenty‐three German Shepherd dogs and 47 other large breed dogs met inclusion criteria. The German Shepherd dog group had higher scores than the control group for compression (P = 0.0099) and herniation (P < 0.001), but not disc degeneration (P = 0.97). In the German Shepherd dog group, intervertebral discs T2‐T3 and T4‐T5 had an increased risk for compression and T3‐T4 had an increased risk for compression and herniation. Findings from this study indicated that German Shepherd dogs may be more likely than other large breed dogs to have spinal cord compression due to cranial thoracic disc herniations. Imaging of the cranial thoracic spine, including T2‐T3, is recommended for German Shepherd dogs with T3‐L3 neurological signs. 相似文献
297.
野桑蚕和家蚕的环境适应性比较研究 总被引:22,自引:10,他引:12
野桑蚕和家蚕对不同组分人工饲料的食性比较研究表明 ,野桑蚕不取食无桑叶粉的人工饲料 ,4 8h不出现疏毛现象 ,其食性较家蚕单一。以完成虫态的积温研究二者对气象环境的适应性 ,发现野桑蚕对气象环境的适应性较家蚕强 ,野桑蚕完成不同虫态所需的有效积温较稳定。对野桑蚕和家蚕添食农药和紫外辐照处理 ,结果表明野桑蚕对不良的环境的耐受性较家蚕强 :添食相同浓度的农药 ,家蚕全部中毒死亡 ,而野桑蚕却部分存活 ,且正常化蛹 ;紫外线辐照可使野桑蚕提前老熟营茧 相似文献
298.
299.
Understanding the causes that determine the spread and subsequent population trends of invasive species is important as it can help predict and manage their impact, as well as advance the theory of invasion. The American mink Mustela vison is a riparian mustelid and an invasive species in several countries. Mink have been introduced to England in the early decades of the last century and have been expanding their range until the mid-eighties. Since then, however, the number of sites occupied by mink has been declining. We investigated three possible causes of such a decline: (1) A downtrend of the fur farming industry; (2) An increase of European polecats Mustela putorius; (3) An increase of Eurasian otters Lutra lutra. Mink trends were derived from data collected by the National Otter Survey, a large-scale long-term survey of the whole of England from 1977 to 2002. We discuss how the observed decline in the number of sites occupied by mink may be due to a combination of an actual decrease in the distribution and density of mink and to a change in the focus of mink activities away from water, rather than to a change in their marking behaviour. Taken together, our results suggest that the decline of mink is related to an increase in the native otter population through interspecific competition, although at a local level also other factors may be important. As the otter population is still increasing, it is likely that the number of sites occupied by mink will continue to decline, a process that may be beneficial to aquatic and semi-aquatic species suffering from mink predation. 相似文献
300.
Development of colour of broccoli heads as affected by controlled atmosphere storage and temperature
Rob E. Schouten Xiaobing Zhang Jan A. Verschoor Els C. Otma L.M.M. Tijskens Olaf van Kooten 《Postharvest Biology and Technology》2009,51(1):27-35
Colour is one of the most important quality attributes of broccoli. Yellowing due to senescence of broccoli florets is the main external quality problem. Controlled atmosphere (CA) storage is a very effective method to maintain broccoli quality. The aim of this paper is to characterise the colour behaviour (measured by RGB colour image analysis) of broccoli as affected by CA and temperature. Data on colour behaviour and gas exchange were gathered for broccoli heads stored in containers at three temperatures and subjected to four levels of O2 and three levels of CO2 concentrations. An integrated colour model is proposed that combines a colour model with a standard gas exchange model. The colour model is based on an existing colour model that describes the formation of (blue/green) chlorophyllide from the colourless precursor, the bidirectional conversion of chlorophyllide into (blue/green) chlorophyll and the decay of chlorophyllide. A multi-response approach was applied, accounting for 92% of the variance. Gas exchange parameters were estimated using the gas exchange model, the colour parameters were estimated using the colour model. Both models are linked via the reaction rate constant that describes the decay of chlorophyllide, as this reaction rate constant was found to be affected by the gas conditions. The integrated model might be applied to predict colour changes of MAP packaged broccoli as a low level of O2 and a high level of CO2 will only affect colour retention at higher temperatures. 相似文献