水电站虹吸式进水口的控制

在对河北省几座已建虹吸式进水口水电站的虹吸控制方式进行分析对比的基础上,给出了一种采用液气射流泵将虹吸体抽成“低管”正虹吸,用“Y”形管中的水封保持真空,事故时利用“高管”自动补气破坏真空的控制系统,并分析了该系统的特点,给出了设计计算方法及计算公式。     

Reproductive biology of the female Japanese mantis shrimp Oratosquilla oratoria (Stomatopoda) in relation to changes in the seasonal pattern of larval occurrence in Tokyo Bay, Japan

ABSTRACT:   The reproductive traits and the monthly larval abundance of the mantis shrimp Oratosquilla oratoria were investigated in Tokyo Bay, Japan, in 2002. The goal of the study was to elucidate the cause of changes in the monthly pattern of larval abundance from the 1980s to the 1990s as these changes relate to variation in the stock size of the adult shrimp. Oogenesis was divided into 10 stages by histological observation. The developmental stage of oocytes in an individual's ovary was synchronous, suggesting that almost all the oocytes in an ovary are spawned at the same time. The size at first maturity was estimated to be 7 ≤ body length ( BL ) < 8 cm. Fecundity was expressed as a function of BL , ranging from 19 300 eggs for 8 cm BL to 92 100 eggs for 14 cm BL . Small female shrimps (<10 cm BL ) spawned around August. Most large female shrimps (≥10 cm BL ) spawned around May, and some large female shrimps also spawned until September. Although most large female shrimps spawned in spring, the larval abundance was low before July and high from August onwards. The results suggest that a substantial decrease in the stock size of large individuals causes the low larval abundance before July.     

Modifying the response to defoliation during vegetative growth in CERES-Maize

CERES-Maize (Vl. 0) predicted no grain yield when 100% defoliation occurred during vegetative growth. This result conflicted with field observations where 100% defoliation early in the vegetative stage did not materially reduce grain yield. CERES-Maize was modified to realistically predict yields when defoliation greater than 50% occurred during vegetative growth by taking into account stem (stem proper and sheath) photosynthesis and translocation of dry matter from the stem to the developing leaves. With these modifications, predictions from CERES-Maize were in good agreement with field measurements when defoliation occurred both early and later in the vegetative stage. This modified version of CERES-Maize can be the basis of a decision support system for defoliating pests of corn where yields can be evaluated under different management strategies and climate scenarios.     

左旋咪唑在生长育肥猪驱虫中的应用研究

本文探讨了5%左旋咪唑注射液按10mg/kg 体重剂量的不同驱虫次数对生长育肥猪驱虫效率、中毒反应及生产性能的影响。结果表明,1)在60～240日龄全期试验内,分别于60和150日龄各驱虫1次的试验Ⅰ组猪日增重极显著高出对照组(不驱虫)的23.9%(p<0.01);也显著高于只在60日龄驱虫1次的试验Ⅱ组(p<0.05),尽管Ⅱ组猪日增重显著高于对照组14.5%(p<0.05)。2)用药后,猪只应激毒性反应为100%,但均能自然康复。3)2次驱虫的效率比1次驱虫的高,且彻底。因此,用左旋咪唑给生长育肥猪驱虫,宜进行2次(分别于60和150日龄),可显著改善生长性能和提高经济效益,适宜在农(山)区养猪中推广。     

萘乙酸对大白菜钙素吸收运转及防治干烧心病的研究

本研究从补钙入手,探索防治干烧心病的方法。用0.7％CaCl_2·2H_2O对和50ppmNAA混合液在大白菜结球期叶面喷洒5次,经8年试验,对大白菜干烧心病的相对防治效果达80％以上。 在此基础上,采用~(45)Ca示踪试验的方法对防病机理做了进一步研究。结果表明,无论从根部还是从叶部加萘乙酸对根部和叶部~(45)Ca的吸收和运转均具有促进作用,并且改变了其在大白菜植株内的分配规律。对照株单位干叶重dpm值自外向内呈下降趋势(130×10~3─60×10~3);用NAA处理株则相反,自外向内呈增加趋势(120×10~3─250×10~3),说明萘乙酸具有促进钙素向叶球中内部运转的功效。这种效果在贮藏期间仍能保持。另外,~(45)Ca向直接受到NAA处理部位的运转量有明显增高的趋势。这一结果为补钙防治干烧心病提供了理论依据。     

Detection and characterization of leptospiral antigens using a biotin/avidin double-antibody sandwich enzyme-linked immunosorbent assay and immunoblot.

A biotin/avidin double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) for the detection of antigens of Leptospira interrogans serovars in experimentally inoculated bovine urine samples was evaluated. Immunoglobulin G (IgG) from rabbits immunized with L. interrogans serovar hardjo type hardjobovis sonicated, whole cell, and formalinized-heated antigen preparations were purified by a protein A-superose column coupled to fast protein liquid chromatography, and evaluated for species specificity in the ELISA. The ELISA using each specific IgG detected as few as 10(4) leptospires of the homologous serovar hardjo diluted in phosphate-buffered saline solution with Tween 20 (PBSS-Tween 20). On immunoblot analysis of proteinase-K-digested whole cell leptospiral preparations, each IgG revealed the presence of bands specific to serovar hardjo, suggesting the presence of serovar-specific epitopes on the lipopolysaccharide molecules. The minimum number of cells of heterologous serovars pomona, grippotyphosa, bratislava, icterohaemorrhagiae and copenhageni detected by each ELISA was greater, ranging from 10(6) to 10(7). The common antigenic determinants observed on immunoblot analysis were different for each specific IgG, except for a major cross-reacting, possibly flagellar, protein doublet at approximately 36-36.5 kDa. Leptospires were equally well detected by the ELISA in both bovine urine and PBSS-Tween 20.     

Characterization of and radioimmunoassay for canine thyroglobulin

Canine thyroglobulin (cTg) has been isolated and purified. It has similar electrophoretic patterns as Tg from other mammalian species. The main fraction had a MW of 660,000, whereas also fractions of a MW of approximately 1,300,000 (dimer) and 330,000 (subunit) were present. The iodine content was 0.8 to 1.0 % (w/w). cTg did not cross-react with antibodies against human Tg to a degree that would allow the use of a radioimmunoassay for human Tg for the determination of cTg in serum or plasma. Therefore a polyclonal antiserum was raised against cTg and a homologous radioimmunoassay was developed, which was sensitive (0.4 μg/l) and specific (cross-reactivity in cTg assay of human Tg, goat Tg, T₄, T₃, and DIT < 0.01 %).

Plasma Tg levels in normal dogs of both sexes and aged 3–15 years amounted to 192 ± 73 μg/l (mean ± SD, n=30). There was no relation between plasma Tg and T₄ levels.     

谈公路动物疫病监督检查站的建设及作用

为了控制疫情的发生、蔓延，防止造成重大的经济损失，保护动物及人类的安全和健康，我国在国道省际交界处设立了动物疫病监督检查站，实施对即将进入流通领域的动物及其产品的监督检查工作。这一举措在动物防疫工作中的作用是非常重要的，但是一些公路动物疫