华农本地早×宜昌橙杂交后代几个性状的遗传分离研究

对华农本地早×宜昌橙的Ｆ１、Ｆ２代杂种，在５个性状上的分离、重组进行了观察分析。结果表明，多胚性受显性基因控制，华农本地早与宜昌橙分别处于显性杂合和隐性纯合状态；种子子叶颜色受一个主基因控制，白色子叶时绿色子叶为显性；嫩梢颜色的遗传基础较为复杂，绿色嫩梢对紫色嫩梢有显性作用；翼叶大小与树体抗寒能力为受多基因控制的数量性状。     

A study on neonatal calf diarrhea induced by rotavirus

This review summarizes the results of a study on rotaviruses isolated from calves affected by neonatal diarrhea.

The results indicated that rotavirus infection is widespread and supported the evidence for an etiologic role of these viruses in neonatal diarrhea. Differences in virulence among bovine rotaviruses appeared also to be confirmed.

Conventionally reared calves were fully susceptible to the experimental infection induced by rotaviruses originating from heterologous hosts, i.e. monkeys, pigs and rabbits.

When rotavirus strains of bovine, simian and rabbit origin were compared by cross neutralization tests, it was found the simian and porcine strains were indistinguishable and both appeared to relate antigenically to the bovine strain.

Finally, it was proven that feeding newborn calves with colostrum and first milk of their dams, previously vaccinated with an inactivated adjuvanted rotavirus vaccine, could prevent the neonatal diarrhea from occurring.     

乙烯长输管道技术综述

根据国内外乙烯长输管道有关文献和现场调查,介绍了国内外乙烯长输管道发展概况,乙烯长输管道的优越性,埋地乙烯管道的设计原则,同时对乙烯管道的施工、运行、维修、安全等方面提出了注意事项。     

壮蚕期不同的给桑量对蚕茧产量和质量的影响

本文利用不同的给桑量分别饲养四、五龄蚕,其结果表明:不同的龄期,给桑量对蚕茧的产量和质量的影响是不一致的.四龄期是影响和决定质量的主要时期,五龄是高产的最重要的环节.     

Forecasting the spatial dynamics of gypsy moth outbreaks using cellular transition models

A series of cellular transition probability models that predict the spatial dynamics of gypsy moth (Lymantria dispar L.) defoliation were developed. The models consisted of four classes: Simple Markov chains, Rook's and Queen's move neighborhood models, and distance weighted neighborhood models. Historical maps of gypsy moth defoliation across Massachusetts from 1961 to 1991 were digitized into a binary raster matrix and used to estimate transition probabilities. Results indicated that the distance weighted neighborhood model performed better then the other neighborhood models and the simple Markov chain. Incorporation of interpolated counts of overwintering egg mass counts taken throughout the state and incorporation of historical defoliation frequencies increased the performance of the transition models.     

乳牛口服过量维生素A对维生素D3及钙磷代谢的影响

从北京郊区某农场选取１０头健康成年黑白花乳牛，随机分为试验（５头，每周每头口服维生素Ａ１００万单位）和对照（５头，不作任何处理）两组。８周以后检测发现，试验组血清钙和无机磷水平呈下降趋势；尾椎骨皮质变薄，密度下降，呈现骨质吸收现象；血清碱性磷酸酶显著下降（Ｐ＜０．０５）；其活性代谢产物２５－羟维生素Ｄ３（２５－ＯＨ－Ｄ３）极显著下降（Ｐ＜０．０１）；１，２５－二羟维生素Ｄ３［１，２５－（ＯＨ）２－     

Influenza in swine in Belgium (1969–1986) Epizootiologic aspects

From 1984 until 1986, influenza isolates were obtained from 59 outbreaks of respiratory tract disease in Belgium. In 21 of the outbreaks, H₃N₂-influenza virus isolates, related to the human A/Port Chalmers/1/73 strain were obtained. All other isolates were H₁N₁-influenza virus strains. The prevalence of variants of the human H₃N₂-influenza virus in the Belgium swine population was determined by examining sow sera which had been collected between 1969 and 1984. The results of this serological study showed that, although a Port Chalmers-like strain was associated with outbreaks of respiratory tract disease in swine only since 1984, such strain was already present in the swine population in 1974, when a low percentage of sow sera (7%) reacted with A/Port Chalmers/1/73. Between 1975 and 1984, antibody against this strain were present in 28–61% of the sera. Furthermore, 3–6% of the sera collected between 1971 and 1980 reacted with the A/Hong Kong/1/68 strain. There were no indications that more recent human H₃N₂-strains (A/Texas/1/77, A/Bangkok/1/79 and A/Belgium/2/81) circulated in the Belgian swine population.     

嘉兴平原桑园土壤分类及肥力的调查

选择浙北嘉兴平原桑园代表性土壤，进行调查，研究其成因、分类及特性，并对高低产桑园土壤的理化性状进行化验分析，明确了嘉兴平原桑园土壤是历史上由人工堆迭而成，在分类系统上归属于潮湿土纲、正常潮湿土亚纲、潮土土类、暗潮土亚类、堆迭土土属，又分为粘质堆迭土、壤质堆迭土、粉质堆迭土３个土种。在统计众多土壤理化性状数据的基础上，暂拟本区高产桑园土壤１６项理化性状，作为本地区桑园地力建设的参考。     

The in vitro cytotoxicity of native and modified trichloroacetic acid-extracted antigens from Fusobacterium necrophorum for mouse peritoneal macrophages

A Boivin lipopolysaccharide-protein complex (LPS-P), Westphal LPS (W-LPS), Boivin LPS (B-LPS), and a lipid A-associated protein (LAP) were extracted from Fusobacterium necrophorum bov 5 strain and chemically analyzed for protein, total nitrogen, hydrolyzed hexosamine, and nucleic acid content. Dose and time effects on the in vitro cytotoxicity of these preparations for mouse peritoneal macrophages were determined. Macrophage monolayers were exposed to 2.0 ml of 10, 100, 250, 500, or 1000 μg/ml solutions of the individual preparations for 1, 2, 4, or 6 hr at 37°C, and relative toxicities were determined; B-LPS> LPS-P> LAP, W-LPS. The effects of heat, NaOH, and trypsin and pronase on the native antigens were determined. Heat treatment had no effect on the cytotoxicity of B-LPS, but increased the toxicity of LPS-P and LAP for macrophages. Alkaline treatment decreased the cytotoxicity of B-LPS and increased the toxicity of LPS-P and LAP for macrophages. Enzyme treatment had no effect on LPS-P toxicity. The relationship of lipid A and protein content to toxicity for macrophages is discussed. Lipid A appears to be important in the cytotoxicity of B-LPS, and the protein components of LPS-P and LAP may contribute to their toxic activity. The ability of these bacterial cellular antigens to destroy phagocytic cells may facilitate the establishment of necrotic abscesses in susceptible hosts.     

Insecticide screening with isolated nerve preparations for structure-activity relationships

The sciatic nerve-sartorius muscle preparation from the frog, the nerve-muscle preparation from the crayfish, and the abdominal nerve cord preparation from the crayfish have been compared for their sensitivity to various insecticides. The crayfish nerve cord was the most sensitive to insecticides and had a broad spectrum of sensitivity. A method was developed with this preparation to compare a large number of synthetic pyrethroids for their potencies to stimulate and block the nerve which is the primary target site. Both stimulating and blocking actions on the nerve can be assessed with this preparation. Certain pyrethroids are active insecticidally despite their weak nerve action, whereas some other pyrethroids are relatively moderate in killing insects despite their potent nerve action. Thus the new method can be effectively used to establish the true structure-activity relationship of synthetic pyrethroids or any other insecticides acting directly on the nerve.