PG99S智能型喷灌机的调试及维护     

肖林刚  王晓冬  帕尔哈丁  马彩雯  张丽  吴乐天  王彦 《农机具之友》2010,(7):23-25

在蔬菜、花卉的工厂化育苗生产中,准确控制肥水的浓度和喷洒的均匀性显得尤为重要,而喷灌设备作为智能型连栋育苗温室的主要浇灌设备,被广泛应用于现代化育苗温室中。该设备自动作业,水量控制精准。本文就PG99S型智能喷灌机介绍其调试方法和故障维修。  相似文献   

Carbohydrate composition in relation to structural stability, compactibility and plasticity of two soils in a long-term experiment   总被引：3，自引：0，他引：3  

B. C. Ball  M. V. Cheshire  E. A. G. Robertson  E. A. Hunter 《Soil & Tillage Research》1996,39(3-4):143-160

The effects of tillage on soil organic carbon content, carbohydrate content, monosaccharide composition, aggregate stability, compactibility and plasticity were investigated in a field experiment on a gleysol and on a cambisol under winter barley in South-East Scotland. Two long-term treatments (direct drilling and conventional mouldboard ploughing for 22 years) were compared with short-term direct drilling and broadcast sowing plus rotavation for 5 years. Carbohydrate released sequentially to cold water, hot water, 1.0 M HCl and 0.5 M NaOH was determined after hydrolysis as reducing sugar equivalent to glucose in both fresh and air-dried samples. All other measurements were made on dry soils only. About 3% of the soluble carbohydrate was extracted by cold water, 10% by hot water, 12% by HCl and 75% by NaOH from both the dry and fresh soils. The total reducing sugars of the fractions were proportional to the total organic carbon determined by dichromate oxidation or C analysis. Organic carbon and carbohydrates were concentrated near the surface of the direct drilled soil, but were more uniformly distributed with depth in the ploughed soil. The surface soil under direct drilling was more stable, less compactible and had greater plasticity limits than under ploughing. However, particle size distributions were unaffected by tillage so that differences in soil properties were attributed to differences in the quantity and quality of organic matter. Differences in compactibility, structural stability and plasticity limits between depths and tillage treatments correlated with total carbon and with total carbohydrates. The hot water extractable carbohydrate fraction correlated best with aggregate stability and the NaOH fraction correlated best with compactibility and plastic limit. Both fractions were greatest in the long-term direct drilled soil. The hot water fraction had a galactose plus mannose over arabinose plus xylose ratio of 1.0–1.6 in comparison to 0.4–0.7 in the NaOH fraction indicating that the microbial contribution within the hot water-soluble fraction was the greater. The hot-water fraction was likely to contain more exocellular microbial polysaccharides involved in the stabilizing of soil aggregates. The hot-water and NaOH carbohydrate fractions may be good indicators of soil organic matter quality relevant to the preservation of good soil physical conditions.  相似文献   

Assessing the green sea urchin (Strongylocentrotus drobachiensis) stock in Maine, USA     

Yong Chen  Margaret Hunter   《Fisheries Research》2003,60(2-3):527-537

The green sea urchin (Strongylocentrotus drobachiensis) fishery is of great importance to Maine’s economy. The fishery took off in the late 1980s as a result of expanding export markets, but has experienced substantial decline in landings since 1992 because of large decreases in urchin stock abundance. Fishery-independent surveys have not been conducted, and no formal stock assessment has been done prior to this study. Using the data collected from the fishery and urchin life history parameters derived from scientific studies, we conducted a formal stock assessment for the urchin stock. A stochastic observation-error length-structured model is used to describe the dynamics of the sea urchin population. A robust Bayesian approach is used for estimating fishery parameters because of concerns of possible outliers in fisheries data and mis-specification of priors. This study shows that the current stock is only 10% of the virgin stock biomass and that the exploitation rate is close to 40% suggesting that a large reduction in exploitation rate is necessary.  相似文献   

Clinical signs, histopathology and genetics of experimental transmission of BSE and natural scrapie to sheep and goats     

Foster JD  Parnham D  Chong A  Goldmann W  Hunter N 《The Veterinary record》2001,148(6):165-171

This paper compares the dinical signs, histopathology, detection of PrPSc protein and PrP genetics of the transmission of BSE to sheep and goats, with the effects of the transmission of natural scrapie from a brain homogenate from a single sheep. After intracerebral and oral inoculations there were similarities in the clinical signs due to the two sources of infection, but there were differences in pathology at the end stage of disease and in the genotypes of the sheep which succumbed to the challenges. The incubation period of BSE was associated with the sheep PrP codon 171 genotype, but the natural scrapie source, despite inducing disease only in known susceptible genotypes, showed no clear association with PrP genotype.  相似文献   

New ovine PrP gene haplotypes as a result of single nucleotide polymorphisms in the PrP gene promoter     

G.T. O'Neill  D. Cairns  L. Toovey  W. Goldmann  & N. Hunter 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2005,122(2):86-94

  相似文献   

Leptin, GH, PRL, Insulin and Metabolic Parameters Throughout the Dry Period and Lactation in Dairy Cows     

PA Accorsi  N Govoni  R Gaiani  C Pezzi  E Seren  C Tamanini 《Reproduction in domestic animals》2005,40(3):217-223

Leptin may play a role in the endocrine-metabolic processes that guarantee the physiological course of lactation in dairy cattle. This study was aimed at determining the changes in plasma concentrations of leptin and some of the main hormones and metabolites involved in the lactogenetic process in high-yielding dairy cows throughout lactation; we also wanted to assess whether leptin secretion is subjected to seasonal influences. Blood samples were collected from 23 Italian Friesian dairy cows from the end of a lactation to the ninth month of the subsequent one; in addition, blood was sampled from 47 dairy cows in different phases of lactation during February and July. Plasma concentrations of leptin, growth hormone (GH), insulin, prolactin (PRL), glucose, non-esterified fatty acids (NEFA) and urea were quantified by either validated radioimmunoassay (RIA) or enzymatic colorimetric methods. At the beginning of lactation, GH concentrations significantly increased, while a significant reduction occurred in leptin and insulin. This endocrine condition, such as the significant increase in NEFA plasma concentrations, is indicative of a marked lipid mobilization. In the more advanced stages of lactation, when both energy and protein balances become positive, leptin plasma concentrations increased, whereas GH and NEFA concentrations declined. During the summer months, a significant increase in leptin plasma concentrations, irrespective of the phase of lactation, was observed. Collectively, our findings suggest that, in dairy cows, leptin may represent a 'metabolic signal' of animal's status of fattening and nutritional level; in addition, leptin seems to be influenced by photoperiod and environmental temperature.  相似文献   

Hepatic vasculopathy and encephalopathy in Brahman-type calves     

PA GILL  WL TOWNSEND 《Australian veterinary journal》1993,70(2):69-69

  相似文献   

Studies on vibrionic infection of sheep and carrion crows     

W A Watson  D Hunter  R Bellhouse 《The Veterinary record》1967,81(10):220-225

  相似文献   

Hematogenous Bacteroides fragilis and Proteus mirabilis infection in a dog with lymphocytic lymphoma of the spleen.     

R L Ridgway  J P Heggers  P B Jennings  W J Hunter 《Journal of the American Veterinary Medical Association》1978,172(6):711-713

  相似文献   

Infectious bronchitis in New Zealand chickens     

I P McCausland  M E Carter  R Hunter 《New Zealand veterinary journal》1972,20(7):120-124

  相似文献