首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   15篇
  免费   0篇
农学   5篇
  1篇
农作物   3篇
水产渔业   1篇
畜牧兽医   3篇
植物保护   2篇
  2024年   1篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2018年   1篇
  2014年   2篇
  2012年   4篇
  2002年   2篇
  2001年   1篇
  1999年   1篇
排序方式: 共有15条查询结果,搜索用时 0 毫秒
1.
M.T. Assad  H.R. Dorry 《Euphytica》2001,117(3):229-232
Russian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), is a serious pest of small grains in many countries. A previous study screened 70 genotypes, collected from different parts of Iran, for RWA resistance. Four crosses were made between two resistant lines (Shz.W-102 and Shz.W-104) and two susceptible lines (Shz.W-101 and Shz.W-103). Parents, F1, F2, and BCF1 seedlings were screened for RWA resistance in the greenhouse by artificial infection. To determine allelism, the two resistant lines were intercrossed and F1, and F2 seedlings were evaluated. Resistance in Shz.W-102 and Shz.W-104, when crossed with Shz.W-101, was controlled by one dominant gene. However, resistance in Shz.W-102 and Shz.W-104, when crossed with Shz.W-103, was controlled by two dominant genes. Genes in two resistant lines segregated independently of each other. A three-gene system was proposed to govern resistance in the lines under study . This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
2.
Brown rust or leaf rust is one of the most important diseases of wheat occurring almost in all wheat-producing regions and reduces crop yield. In order to produce resistant cultivars, it is necessary to identify resistance genes in different germplasms and combine them in (a) suitable stock(s). To identify the presence of the leaf rust resistance genes using STS and SCAR markers, 83 Iranian wheat genotypes, Lr near-isogenic lines in Thatcher (positive controls), and the cultivar Thatcher (negative control) were used. After growing plants in the greenhouse, DNA was extracted by SDS method. Following that, polymerse chain reaction was performed for the markers of the resistance genes Lr9, Lr26, Lr28, Lr34, and Lr35 which amplified 1,100, 1,100, 378, 150, and 900 bp bands, respectively. Based on the results, the resistance genes Lr9 and Lr35 were only present in the positive controls. The resistance gene Lr26 was only detected in four cultivars; Arta, Pishtaz, Shiroodi, and Falat, and the gene Lr34 was present in six cultivars (Akbari, Bam, Tajan, Khazar 1, Sistan and Niknezhad). The Lr28 primer amplified a band of the same size in all genotypes even the negative control and therefore the presence/absence of this gene could not be validated. These results indicate the necessity for designing a specific primer for Lr28. In general, only the genes Lr26 and Lr34 were present in some genotypes. The genes Lr9 and Lr35 were not present in this collection and as based on rust surveys, no virulence has been detected for Lr9 and Lr28, so they could be transferred to suitable lines from donor sources.  相似文献   
3.
Bioassays have shown that sand freshly contaminated by ovipositing females of the gregarious desert locust Schistocerca gregaria (Forskal) is more effective in inducing further oviposition from conspecifics than contaminated sand stored for three or six months, which contrasts with results obtained previously with Locusta migratoria (Reiche & Farmaire). The activity of contaminated sand correlated with the levels of three unsaturated aliphatic ketones, (Z)-6-octen-2-one, (E,E)-3,5-octadien-2-one and its geometric isomer (E,Z)-3,5-octadien-2-one present in the volatile emissions from the sand.  相似文献   
4.
This article correlates draw frame settings with quality characteristics of sliver and ring spun yarn using artificial neural networks. Considering the importance of draw frame as the last quality improvement machine in the spinning process, the quality influencing parameters of the draw frame were used as input for artificial neural networks. The neural networks were trained using a combination of Levenberg-Marquardt algorithm and Bayesian regularization for better generalization of the networks. Cross validation was performed for each trained network to test the performance of networks. The promising results achieved by this research work emphasize the ability of neural networks to predict the quality characteristics of sliver and yarn using the artificial neural networks. Therefore, draw frame parameters can be adjusted on the basis of required sliver and yarn quality. Furthermore, machines can be involved in the decision making process in spinning mills.  相似文献   
5.
A case control study on farm level was conducted at the Clinic for Ruminants, LMU Munich, to identify possible risk factors associated with the observed increase in numbers of calves showing clinical signs of Bovine Neonatal Pancytopenia (BNP) since 2006 in southern Germany. Interviews were conducted between August 2008 and June 2010. The characteristics of 56 dairy farms with at least one confirmed case of BNP (thrombocytopenia and leukocytopenia and/or typical findings in post-mortem examination and bone marrow histology) were compared with those of two sets of 50 control dairy farms each, with no history of BNP. The first set of 50 control farms was selected randomly from veterinary practices which had never observed a BNP case on the farms they serviced. The second set of 50 control farms was matched by the veterinary practices which had provided case farms. Two separate analyses were conducted: (1) case farms (n=56) vs. randomly selected control farms (n=50) and (2) case farms (n=56) vs. a matched set of control farms (n=50). All variables with p<0.2 in the univariable analysis were included in stepwise logistic regression models. In the first analysis, only the use of PregSure(?) BVD vaccine was positively associated with BNP with an odds ratio of 1292 (95% CI: 114-14707). In the second analysis, conditional logistic regression models did not converge, therefore non-conditional logistic regression models were conducted. In the non-conditional analysis five variables remained in the model, three of which were negatively associated with BNP: the use of vitamin E and selenium, the frequent use of mastitis tubes, and the use of stem growth regulators in grain production. The use of prophylactic measures (such as control of parasites or vaccination of calves against respiratory disease) was positively associated with BNP with an odds ratio of 14.3 as well as the use of PregSure(?) BVD vaccine with an odds ratio of 426 (95% CI: 20-9095).  相似文献   
6.
Bovine neonatal pancytopenia (BNP) is mainly characterized by multiple haemorrhages, thrombocytopenia and leukocytopenia as a result of bone marrow depletion. BNP can be induced in healthy calves through application of colostrum from BNP donors, proofing that BNP is mediated to maternal alloantibodies. Alloantibody binding to bovine blood cells is present in sera and colostra of BNP donors and is probably initialized by vaccination with a certain BVD vaccine. To understand etiology and pathomechanisms of BNP, we closely characterized disease inducing antibodies regarding immunoglobulin subclass and binding specificities to peripheral blood derived leukocytes and platelets. By exact phenotyping the targeted blood cell subsets, including platelets for the first time, we investigated that BNP alloantibodies are exclusively of IgG1 subclass. Interestingly, IgG1 of BNP colostra bound to 70% leukocytes and 100% platelets irrespective of different bovine breeds and cellular maturity of all specimens tested. Furthermore, staining pattern on platelets as well as leukocyte subsets by BNP-IgG1 alloantibody exposed 100% reactivity to platelets, granulocytes and monocytes. Interestingly, the main part of T-helper cells was not bound by colostral alloantibodies. Our results point to a crucial role of IgG1 antibodies in BNP and to a target antigen that is expressed by all cells of myeloid lineage, but only partially by the lymphoid lineage.  相似文献   
7.
Maghemite glass fibre nanocomposite with excellent magnetic and adsorption properties was successfully developed from nontoxic and eco-friendly reagents by thermal decomposition approach. The developed nanocomposite was utilized in adsorption of methylene blue which follows Freundlich adsorption isotherm. The excellent value of adsorption capacity (51.31 mg g-1) as compared to other adsorbents recommends its potential role for adsorption phenomenon in multiple applications. The developed nanocomposite can be recycled and reused easily. Surface and other functional characteristics of developed nanocomposite were determined through scanning electron microscopy, X-ray diffraction, raman spectroscopy, energy dispersive X-ray spectroscopy and vibrating sample magnetometer. The obtained results revealed that maghemite glass nanocomposite is a potential tool that can be utilized in waste water treatments.  相似文献   
8.
Background:IM, a strong and selective TKI, has been approved as the front line of treatment in CML patients. In spite of satisfactory results of imatinib in the treatment of patients with CML, patients with treatment failure or suboptimal response developed resistance that might be because of pharmacogenetic variants. This study attempted to evaluate the influence of ABCB1 gene polymorphisms and smoking on CML risk and resistance to imatinib. Methods: ABCB1 (c.1236C>T, c.3435C>T) polymorphisms were genotyped in 98 CML patients and 100 sex- and age-matched healthy subjects by PCR-RFLP method, followed by sequencing. The patients were evaluated for cytogenetic response by the standard chromosome banding analysis in regular intervals. Results:Our results showed that c.1236CC genotype was significantly associated with imatinib resistance (OR = 3.94; p = 0.038). Analysis of the joint of SNP-smoking combination showed that smokers with c.1236TT/CT and c.1236CC genotypes had the increased risk of CML (OR = 6.04; p = 0.00 and OR = 4.95, p = 0.005) and treatment failure (OR = 5.36, p = 0.001 and OR = 15.7, p = 0.002), respectively. Smokers with c.3435TT/CT and c.3435CC genotypes also displayed the elevated risk of CML development (OR = 6.01, p = 0 and OR = 4.36, p = 0.011) and IM resistance (OR = 5.61, p = 0.001 and OR = 13.58, p = 0.002), respectively. Conclusion:Our findings suggest that c.1236CC genotype has clinical importance in the prediction of treatment outcome with IM, and smoking could have a synergistic role in CML risk and IM resistance. Key Words: ATP binding cassette transporter subfamily B, Imatinib mesylate, Smoking  相似文献   
9.
The computed tomography (CT) imaging findings of a celiacomesenteric trunk (CMT) in a 1‐year‐old dog with primary hypoplasia of the portal vein (PHPV) are described. Computed tomography angiography revealed acquired porto‐systemic shunts secondary to portal hypertension and a common origin of the celiac and cranial mesenteric arteries. The imaging findings and the association of a CMT with other vascular diseases have never been reported in dogs. The recognition of this rare arterial anomaly should prompt to investigate possible concurrent vascular diseases and may influence the planning of abdominal surgeries.  相似文献   
10.
A survey for primary and secondary Hymenopteran parasitoids of scale insects (Homoptera: Coccoidea) in fruit orchards (apple, plum, date, olive, fig, citrus), was conducted in Syria during 2009–2012. Thirty three species of parasitoids belonging to the families Aphelinidae, Encyrtidae, Eulophidae and Pteromalidae were recorded as parasitoids on scale insects. Thirty two of these were primary parasitoids and one was a hyperparasitoid. The family with the greatest number of genera and species is Encyrtidae with 8 genera (48% of the total) and 12 species (35% of the total). The genus with the greatest number of Encyrtid species was Metaphycus. Parasitoids of scale insects identified included several species already included on the List of biological control agents widely used in the EPPO region ‘EPPO Positive list' and suggestions for additions to this list were made.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号