微观蜡晶特征在流变曲线上的宏观体现     

聂向荣  杨胜来  丁景辰 《油气储运》2014,(3):255-258

为了研究证明含蜡原油流变曲线和微观蜡晶两者之间存在一定的关联,测试了广范围剪切速率下的含蜡原油流变曲线,确立了微观蜡晶和流变曲线之间的定性关系,并且取得以下认识：广范围剪切速率下的含蜡原油流变曲线能够一定程度地体现微观蜡晶特征,其中低剪切速率下的流变曲线能够体现蜡晶形态,高剪切速率下的流变曲线能够体现蜡晶结构;并非温度越低,剪切速率对粘度的影响程度越大,在高剪切速率下,有可能存在相反的情况;在低温条件下,剪切速率存在一个临界值,只有当剪切速率大于该值时,粘度才会出现较为明显的下降;温度越低,形成的蜡晶网格结构越稳定,需要较大的剪切应力,蜡晶网格结构才能破坏。该研究成果深化了对含蜡原油流变性的认识,具有一定的理论意义。（图6,表1,参15）  相似文献   

2.11 Test method for examination of the sensitivity of Uncinula necator to pyrifenox     

R. KÜNG 《EPPO Bulletin》1991,21(2):317-319

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Kinetics of endotoxin, complement and platelet-activating factor (PAF) induced vascular permeability in Greyhounds     

P. C. MILLS  J. C. NG  A. A. SEA WRIGHT  D. E. AUER 《Journal of veterinary pharmacology and therapeutics》1994,17(6):470-472

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Electrophoretic mobility of Bacteroides nodosus pilus antigens     

B G HANDLEY  M L NG  C L SCHWARTZKOFF 《Australian veterinary journal》1986,63(2):62-63

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Effects of local anaesthesia of 4 to 8 hours duration on the acute cortisol response to scoop dehorning in calves   总被引：1，自引：0，他引：1  

CM McMEEKAN  DJ MELLOR  KJ STAFFORD  RA BRUCE  RN WARD  NG GREGORY 《Australian veterinary journal》1998,76(4):281-285

Objective To determine the effect of a long-acting local anaesthetic on the plasma cortisol response in calves dehorned using a scoop.
Design A physiological study with controls.
Procedure Seventy female calves, 3 to 4 months old, were divided into seven groups and dehorned by scoop with or without a long acting local anaesthetic (bupivacaine) which provides local anaesthesia for 3 to 4 h. In some treatment groups the local anaesthetic was given a second time, after 4 h, to give 8 h of anaesthesia. Blood samples were taken before and for 9 h after treatment and plasma cortisol concentrations were measured.
Results Scoop dehorning caused a marked rise in plasma cortisol concentration, which returned to pre-dehorning values after 7 h. The cortisol concentrations of calves given bupiva-caine were similar to those of control animals for 4 h after dehorning, but then a significant and protracted rise occurred, with concentrations returning to pretreatment values at about 9 h after dehorning. In calves given a second treatment of bupivacaine 4 h after dehorning, the plasma cortisol concentration remained similar to control values for 8 h after dehorning but then increased sharply.
Conclusions During its period of activity long-acting local anaesthetic prevented the rise usually seen after scoop dehorning in plasma cortisol concentrations; by inference it also alleviated the pain-induced distress caused by this procedure. However, when its effects had worn off the plasma cortisol values rose sharply indicating that animals still experienced pain-induced distress despite local anaesthetic being administered.  相似文献   

三峡库区坡耕地粮经果复合垄作对土壤水分特征的影响   总被引：1，自引：0，他引：1  

廖晓勇  罗承德  陈治谏  王海明  田道平 《干旱地区农业研究》2008,26(5):75-79

减缓、减轻干旱的发生与危害是三块库区坡耕地持续利用的关键.在坡度15°标准径流小区,以聚土垄作和农林复合为基本方法,营建坡耕地粮经果复合垄作模式,并对模式的土壤水分状况进行了长期定位观测.2002～2005连续4年试验结果表明,粮经果复合垄作能有效改善坡耕地土壤结构,利于土壤保持适宜的透水性和持水性,土壤有效库容扩大了145.2 m3/hm2;同时,增加了土壤贮水,提高了贮水利用率,尤其是底层贮水利用率,比较平作对照,贮水库客和贮水利用率分别增大了5.73%、5.32%;此外,垄沟拦蓄了地表径流,减少径流损失达74.18%～95.81%,有利于降水入渗补给及旱季底墒的保护.  相似文献   

Degradation and adsorption of terbuthylazine and chlorpyrifos in biobed biomixtures from composted cotton crop residues     

Konstantina Kravvariti  Nikolaos G Tsiropoulos  Dimitrios G Karpouzas 《Pest management science》2010,66(10):1122-1128

BACKGROUND: Biobeds have been well studied in northern Europe, whereas little is known regarding their use in southern Europe. The degradation and adsorption of terbuthylazine (TA) and chlorpyrifos (CP) were studied in three different biomixtures composed of composted cotton crop residues, soil and straw in various proportions, and also in sterilised and non‐sterilised soil. RESULTS: Compost biomixtures degraded the less hydrophobic TA at a faster rate than soil, while the opposite was evident for the more hydrophobic CP. These results were attributed to the rapid abiotic hydrolysis of CP in the alkaline soil (pH 8.5) compared with the lower pH of the compost (6.6), but also to the increasing adsorption (K_d = 746 mL g^?1) and reduced bioavailability of CP in the biomixtures compared with soil (K_d = 17 mL g^?1), as verified by the adsorption studies. CONCLUSIONS: Compost had a dual but contrasting effect on degradation that depended on the chemical nature of the pesticide studied: a positive effect towards TA owing to increasing biodegradation and a negative effect towards CP owing to increasing adsorption. Overall, composted cotton crop residues could be potentially used in local biobed systems in Greece, as they promoted the degradation of hydrophilic pesticides and the adsorption of hydrophobic pesticides. Copyright © 2010 Society of Chemical Industry  相似文献   

中华蜜蜂MRJP7基因的原核表达及多克隆抗体的制备     

李艳  陈艳霞  沈立荣  张传溪 《上海交通大学学报(农业科学版)》2008,26(2):109-113

用PCR方法从含中华蜜蜂Accmrjp7基因的质粒DNA模板中扩增出MRJP7成熟肽编码区片段,将该片段克隆入原核表达载体pGEX-4T-2,在大肠杆菌（Escherichia coli）BL21（DE3）中进行融合表达,SDS—PAGE和薄层扫描显示,该基因得到高效表达,表达产物大小约为66kDa,占细胞总蛋白的22．8％。利用割胶回收的方法,获得目的蛋白,注射兔子制备多克隆抗体,并利用所获抗体进行Western blot印迹分析,检测MRJPs,获得特异性条带。  相似文献   

Influence of soil physicochemical and biological properties on the degradation and adsorption of the nematicide fosthiazate   总被引：1，自引：0，他引：1  

Pantelelis I  Karpouzas DG  Menkissoglu-Spiroudi U  Tsiropoulos N 《Journal of agricultural and food chemistry》2006,54(18):6783-6789

The degradation and adsorption of the organophosphorus nematicide fosthiazate were investigated in nine soils with various physicochemical and biological characteristics. Fosthiazate was more persistent in acidic soils (pH <6), with half-life (t1/2) values ranging from 53.3 to 57.7 days, compared to soils with higher pH (pH >7), with t1/2 ranging from 14.1 to 20.7 days. Application of antibacterial and antifungal antibiotics to soil samples resulted in a significant inhibition of fosthiazate degradation only in two of the three acidic soils. In contrast, soil autoclaving resulted in doubling the t1/2 of fosthiazate in all studied soils, suggesting that both microbial and abiotic processes contribute to fosthiazate degradation. Statistical analysis indicated a significant negative correlation (P < 0.01) between soil pH and t1/2. Fosthiazate was generally weakly adsorbed with Freundlich adsorption coefficient (Kf) values ranging from 1.23 to 2.74 mL/g. Fosthiazate concentration was strongly correlated with soil organic matter content with higher Kf values in soils with higher organic matter content (P < 0.01). The mean t1/2 and Kf values derived from the laboratory studies were used to parametrize the FOCUS groundwater (GW) models PRZM, PELMO, PEARL, and MACRO for nematicide application in potato and tomato crops. Predicted environmental concentrations produced by the models PEARL and MACRO suggested a potential risk for GW in several scenarios, unlike PELMO and PRZM, which predicted low risk for GW. These findings suggest that the environmental fate of fosthiazate is strongly influenced by soil characteristics and that this nematicide should be used with care in acidic, light soils with low organic matter content.  相似文献   

Implications of intensification of pastoral animal production on animal welfare     

KJ Stafford  NG Gregory 《New Zealand veterinary journal》2013,61(6):274-280

The intensification of pastoral animal production results from several major developments including increased forage production and utilisation, diet supplementation, breeding animals to increase milk, meat or wool production, and changes in management. The impact of increased intensification on welfare will differ across species and systems. More intensive-grazing systems and the feeding of novel forages will underpin all moves to intensification. More intensive grazing generally reduces opportunities for shade and shelter. Improved nutrition will generally benefit welfare but competition for available feed may cause increased social pressure. Increased flock and herd size will be associated with a reduction in the human:animal ratio and less time to observe individual animals. Remote monitoring of activity and health might counter this impact.

Intensification of dairy production will result in larger herds, more year-round milking, robotic milking, use of housing and yards year round, and total mixed-ration feeding. Larger herds mean longer distances to walk to and from the dairy shed, and more lameness and less time to spend on self-maintenance activities such as grooming. Holding and feeding dairy cows on yards will cause an increase in lameness and mastitis and perhaps an increase in agonistic behaviour but will reduce time spent walking. Intensification of sheep production will involve increased flock size, increased fecundity, breeding from hoggets, and breeding ewes all year round. Housing during lambing might be considered appropriate, as would feeding to lift milk yields. Increased fecundity with an increase in triplets will increase lamb mortality rates, but housing ewes, when managed well, will result in reduced lamb mortality. Intensification of lamb finishing will be by improved nutrition. Intensification of beef production will include more breeding of heifers at 15 months, and more problems with dystocia.

Intensification of pastoral production will have positive and negative effects on animal welfare. The balance will be determined by the quality of management and stockmanship, and the pressure on businesses to be profitable.  相似文献