棉花种子介电特性的试验研究   总被引：2，自引：1，他引：2  

杨戬  史建新  巴彦亮  郭俊先  王庆慧 《农产品加工．学刊》2005,(5):14-16

将棉花种子简化为一种复合介质模型,通过试验测试种子的介电常数,探讨种子的介电特性,分析频率、湿度与种子介电特性的关系,得出介电常数随各参数变化的规律,为合理地确定介电式种子分选机的结构参数和工况参数提供理论依据。对外表完整与表面破裂的种子进行吸湿性的对比试验研究,从而为提高介电式种子分选机的分选效果创造条件。  相似文献   

A nationwide survey on seroprevalence of Neospora caninum infection in beef cattle in Uruguay     

Bañales P  Fernandez L  Repiso MV  Gil A  Dargatz DA  Osawa T 《Veterinary parasitology》2006,139(1-3):15-20

Bovine abortions due to Neospora caninum infection have been reported worldwide and its economic impact on the beef industry has been acknowledged as a problem. Uruguay has the largest export value of beef per acre in South America. However, no data on the prevalence of N. caninum infection have been available in this country. The objective of this study was to estimate the prevalence and distribution of N. caninum infection in beef cattle in Uruguay through a nationwide survey. A two stage sampling design was used with farms being selected in stage one and animals being selected in stage two. A brief questionnaire was administered on each farm. Seroprevalence of N. caninum in 4444 beef cattle from 229 farms in all the counties, except Montevideo, of Uruguay was determined by an ELISA. The data were then analyzed to identify associations between infection and variables such as type of animal (cow or heifer), herd size, use of veterinary advice, productivity of the soil in relation to the national average, use of improved grass, use of mineral salts, use of supplemental feed, and presence of a dog(s) on the farm. The estimated proportion of positive farms for all the beef cattle operations was 69.2% (95% confidence interval [CI], 53.7-84.7). The overall cattle seroprevalence was estimated as 13.9% (95% CI, 11.6-16.3). The prevalence estimation by animal category was 14.3% (95% CI, 11.4-17.2) for beef cows and 12.9% (95% CI, 10.0-15.8) for beef heifers. There was no significant difference in the estimated prevalence between the two animal types. There was no significant difference in the animal level prevalence of N. caninum infection among different herd sizes. None of the herd demographic or management variables was significantly associated with the seropositivity to N. caninum infection. In conclusion, these results show that N. caninum infection is common among beef herds across Uruguay. Since the beef industry is one of the key industries in Uruguay, the economic effect and risk factors of N. caninum infection among beef cattle in this country should be further evaluated in the near future.  相似文献   

Assessment of pregnancy‐associated glycoprotein (PAG) concentrations in swamp buffalo samples from fetal and maternal origins by using interspecies antisera     

Van Hanh NGUYEN  Olimpia BARBATO  Xuan Nguyen BUI  Jean‐François BECKERS  Noelita Melo de SOUSA 《Animal Science Journal》2012,83(10):683-689

Pregnancy‐associated glycoproteins (PAG) constitute a large family of glycoproteins found in the outer placental epithelial cell layer of the placenta in Eutherian species. In ruminants, they are noted to be structurally closely related among the different species. This study was designed to determine PAG concentrations in maternal and fetal plasma, allantoic and amniotic fluids in buffalo species. Antisera (AS) generated in rabbits against distinct PAG molecules were used in three radioimmunoassay (RIA)‐PAG systems: RIA‐1 (antiserum raised against bovine PAG67kDa; AS#497), RIA‐2 (antiserum raised against caprine PAG55 + 62 kDa; AS#706) or RIA‐3 (antiserum raised against buffalo PAG; AS#859). Samples were collected at a slaughterhouse (n = 67). PAG concentrations determined by RIA‐2 gave significantly higher results in both allantoic and amniotic fluids (12.7 ± 2.1 ng/mL and 24.0 ± 7.3 ng/mL, respectively). Regarding maternal and fetal plasma, PAG concentrations obtained by RIA‐2 (21.8 ± 2.4 ng/mL and 20.2 ± 2.5 ng/mL, respectively) and RIA‐3 (25.0 ± 2.2 ng/mL and 21.9 ± 3.2 ng/mL, respectively) were higher than those obtained by RIA‐1 (15.5 ± 1.4 ng/mL and 16.1 ± 1.8 ng/mL, respectively). The correlation among the three systems was very high. The study clearly reveals the ability of different PAG‐RIA systems to measure PAG concentration in swamp buffalo samples.  相似文献   

西藏玛旁雍错流域湖泊面积变化及成因分析   总被引：5，自引：0，他引：5  

拉巴  边多  次珍  拉巴卓玛  陈涛 《干旱区研究》2012,29(6):992-996

利用1975年地形图、1990年、1999-2009年TM卫星遥感影像和近35 a(1975-2009年)气温、降水、积雪日数、蒸发量等气候资料,分析研究了位于西藏阿里地区南部普兰县境内玛旁雍错、拉昂错湖泊面积变化对气候变化的响应。结果表明：在过去35 a里玛旁雍错、拉昂错面积先减少后增加,总体呈减小趋势,到2009年玛旁雍错面积为415.44 km²,拉昂错面积为261.36 km²。与1975年相比2个湖泊面积分别减少了1.56 km²和11.01 km²;受气候变暖的影响,流域附近的冰川面积也在加速退缩。对1975-2009年普兰县气象资料统计分析可知,降水量减少是导致湖泊面积缩小的主要原因,蒸发量不显著的增加及雪冰消融也是近几年湖泊面积波动变化的原因之一。  相似文献   

猪饲料产品美誉度如何建立——饲料企业营销诊断之二     

巴国 《饲料广角》2007,(8):41-42

产品美誉度低,客户网络也难于建立巩固,销量难以稳定上升。饲料公司在确定了自己的营销战略、产品定位、通路策略、促销策略,开发市场采用集中人力攻击,并配合以广告投入、促销措施、技术服务等手段,下决心一个一个市场开发,一个一个市场巩固,逐步扩展。  相似文献   

Efficacies of liposome-encapsulated enrofloxacin against Staphylococcus aureus infection in Anatolian shepherd dog monocytes in vitro     

Baş AL  Simşek A  Erganiş O  Corlu M 《DTW. Deutsche tier?rztliche Wochenschrift》2005,112(6):219-223

The aim of this study was to evaluate the intracellular activity of two types of liposome-encapsulated enrofloxacin (LE) compared with free enrofloxacin and non-treated control against Staphylococcus aureus, phagocytosed by monocytes in healthy Anatolian Shepherd dogs. Enrofloxacin was encapsulated with two different types of liposome in multilamellar large vesicles (MLV). Type A MLV were composed of 15 mg phosphatidylcholine and 35 mg cholesterol, Type B MLV were composed of phosphatidylcholine, cholesterol and enrofloxacin in a molar ratio of 1:1:1. Intracellular activity was estimated by comparing the numbers of bacteria surviving intracellularly in monocytes exposed to free enrofloxacin and LE for 4 h at the doses of 0.25, 0.5 and 1 microg/ml, with those surviving intracellularly in untreated control monocytes. All three forms of enrofloxacin (free, Type A and B liposomes) increased the intracellular killing of S. aureus in a concentration dependent manner. Comparison of 1 microg/ml Type B LE revealed that killing activity was significantly higher than those of other concentrations. The results showed that LE was superior in reducing the number of intracellularly located bacteria compared to the free drug and control. The beneficial effect of liposomal encapsulation is presumably due to the fact that both liposomes and bacteria are localized at the same spot in phagocytic cells.  相似文献   

Effects of salt stress on ion accumulation and antioxidative enzyme activities of Oryza sativa L. and Echinochloa oryzicola Vasing     

HOAI THI THU NGUYEN  IE SUNG SHIM  KATSUICHIRO KOBAYASHI  KENJI USUI 《Weed Biology and Management》2005,5(1):1-7

The effects of salt stress on physiological factors, such as inorganic ion absorption and antioxidative enzyme activities, of rice ( Oryza sativa L. cv. Anapurna) and Echinochloa oryzicola Vasing were investigated. Although having similar morphology, rice and E. oryzicola possessed considerably different salt-tolerance mechanisms. Echinochloa oryzicola was more salt-tolerant than rice. When exposed to salt stress (100 mmol L⁻¹ sodium chloride, NaCl; six days), E. oryzicola had the ability to limit the accumulation of sodium ions (Na⁺), maintained high potassium ion (K⁺) content and had a constantly higher K⁺/Na⁺ ratio than rice. Rice was not effective in limiting Na⁺ absorption but had a higher antioxidative capacity than E. oryzicola . The constitutive activities of superoxide dismutase (SOD) and catalase of rice were three and five times higher than that of E. oryzicola, respectively. Induced activities of SOD, ascorbate peroxidase and glutathione reductase were also higher in rice than in E. oryzicola . The high antioxidative capacity was one of the tolerance mechanisms used by rice to cope with salt stress. Therefore, the salt tolerant-mechanisms are different between the two plants.  相似文献   

基于粗集约简的Fuzzy ART设备状态监测方法     

栾凤艳  谷吉海  巴兴强 《东北林业大学学报》2007,35(6):99-101

针对复杂设备系统的多工况状态监测问题,提出一种基于粗集属性约简的FuzzyART神经网络状态监测方法。该方法利用粗集的信息决策表和决策矩阵对系统的监测参数进行约简提取,降低FuzzyART输入向量的维数。实例测试结果表明,采用粗集约简提取的监测向量与原监测向量具有相同的监测能力,且提高了网络的学习效率。  相似文献   

商品鹅感染鸭瘟的诊断     

巴英  文明 《贵州畜牧兽医》2006,30(3):28-28

鸭瘟(Duck plague,DP)是由疱疹病毒科a-疱疹病毒亚科鸭瘟病毒引起鸭、鹅及多种雁形目动物的一种急性、热性传染病.本病常在我国广大养鸭群中暴发流行或散在发病,且主要侵害种鸭群或蛋鸭群.但近年来,随着养鹅业的规模化与集约化发展,该病对商品鹅的感染发病呈现上升趋势,且在不同日龄的鹅群中传播,给养鹅业造成重大经济损失.2005年6～7月间,本地区某一养鹅户饲养的鹅群发生了一种发病急、发病率和死亡率均较高的传染病,经本实验室诊断,确诊为鸭瘟病毒感染所致.现将诊断结果报道如下.  相似文献   

Zoogeographical barriers causing discontinuous osteometrical variations in the northern treeshrew skulls     

Hideki ENDO  Truong Son NGUYEN  Dinh Duy NGUYEN  Motoki SASAKI  Junpei KIMURA  Tatsuo OSHIDA  Masaya YAGO  Ngoc Tu LY  Thi Tham NGUYEN  Masaharu MOTOKAWA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(10):1534

Morphological variation of the skull was examined in the northern treeshrew (Tupaia belangeri) from various localities across Southeast Asia. Through a multivariate analysis, the treeshrews from South Vietnam exhibited distinct morphological characteristics compared to other populations from Thailand and Laos, and Malaysia. The plots of the specimens of North Vietnam are not randomly mixed with Thailand plots segregation in the scatteregrams of canonical discriminant analysis. Since the skulls of the population from North Vietnam were morphologically similar to those form central Laos and northern and northeastern Thailand, the zoogeographical barrier effect of Mekong River was not clearly confirmed. The population of the Kanchanaburi in western Thailand is clearly smaller in size compared to the other populations. The southern border of the distribution of this species is determined by the Isthmus of Kra or Kangar-Pattani Line. In the northern treeshrew, which is distributed from southern China to Bangladesh and southern Thailand, we have detected osteometrical geographical variation driven by geography. These results indicate that the skull morphology in the Tupaia glis-belangeri complex distinctively differs in South Vietnam, western Thailand, and southern Thailand. The zoogeographical barrier and factor separating these districts are expected to clarify in the future.  相似文献