陕西省姜片吸虫病疫源地媒介植物的研究

<正> 前言家畜疫源地一般是以家畜为主的生物群落(包括疫病病原体、宿主动物、有时还有传播者、中间宿主和补充宿主在内)以及和这些生物群落的成员相适应的生物生长区组成的。病原体、宿主动物、传播者(或中间宿主、补充宿主)及生物生长区是疫源地四要素。     

鸡传染性法氏囊病控制措施的探讨

<正> 鸡传染性法氏囊病(Infectious bursal disease,简称IBD)又称甘波罗病,是青年鸡的一种急性、高度接触性传染病。该病以法氏囊淋巴细胞的严重破坏为主要特征,其他器官损害较轻。鸡群感染本病后出现严重的免疫抑制,并对多种疫病增加了易感性。1990年以来,本病在我省呈爆发性流行,发病鸡群占鸡群总数的70—90％,死亡率在20—30％之间,重者可达80％。这次流行的特点是:无论非免疫鸡群,还是免疫鸡群或无母源抗体的雏鸡都可感染发病,病程5—7天,呈一过性。15—150日龄的鸡均可感染发病。剖检死鸡,可见骨骼肌出血;法氏囊严重出血,外观呈紫萄葡样;肝脂肪变性,质脆;心冠脂肪、肠道有时也见出血;肾脏肿胀,呈灰白色。据不完全统计,我省1990年因本病致死的鸡达60万只左右,直接经济损失约300万元。     

鸡IL-1βcDNA片段的克隆及序列分析

本文以鸡外周血单个核细胞总 Ｒ Ｎ Ａ 为模板,据已报道的８ 种哺乳动物 Ｉ Ｌ—１β核酸序列保守区设计合成１ 对引物,反转录合成ｃ Ｄ Ｎ Ａ 链,经 Ｐ Ｃ Ｒ 扩增,回收扩增后的 Ｄ Ｎ Ａ 片段,用ｋｌｅｎｏｗ 酶处理,与 Ｐｕ ｃ１ ９ ／ Ｓｍ ａ Ｉ 连接构成重组质粒,转化宿主菌大肠杆菌 Ｊ Ｍ１ ０ ９ ,筛选出含有插入片段的重组质粒,用 Ｐ Ｃ Ｒ 及酶切分析鉴定,结果表明获得了带有鸡 Ｉ Ｌ－ １β片段的ｃ Ｄ Ｎ Ａ 克隆;再经序列分析测定,得知此片段长为２７０ｂｐ ,与人及小鼠 Ｉ Ｌ—１β基因核苷酸序列同源性分别为４５ ％ 和３０ ％ 。     

猪凝血酶的分离纯化及部分性质研究

经等电点沉淀,ＤＥＡＥ离子交换纤维素柱层析和ＳｅｐｈａｄｅｘＧ－１００分子筛层析从猪血浆中纯化得到到猪凝血酶,酶比活力为２０００Ｕ／ｍｇ,纯化倍数为１００,酶活力回收为５６％,酶反应的最适ＰＨ和温度分别为７．０和３７℃,ＳｅｐｈａｄｅｘＧ－１００层析测得酶分子量为３６０００。猪凝血酶的稳定性较差,４０℃保温２７ｈ,酶活力下降８４％。高浓度的盐对酶稳定性有较大的影响,在２ｍｏｌ＝／ＬＮａＣｌ下放置３     

Contributions of the visual ventral pathway to long-range apparent motion

Objects displaced intermittently across the visual field will nonetheless give an illusion of continuous motion [called apparent motion (AM)] under many common conditions. It is believed that form perception is of minor importance in determining AM, and that AM is mediated by motion-sensitive areas in the "where" pathway of the cortex. However, form and motion typically interact in specific ways when natural objects move through the environment. We used functional magnetic resonance imaging to measure cortical activation to long-range AM, compared to short-range AM and flicker, while we varied stability of structural differences between forms. Long-range AM activated the anterior-temporal lobe in the visual ventral pathway, and the response varied according to the form stability. The results suggest that long-range AM is associated with neural systems for form perception.     

圆形截面钢筋砼偏心受压构件正截面承载力的实用计算法

本文根据《砼结构设计规范》（ＧＢＪ１０－８９）对圆形截面钢筋砼偏心受压构件正截面承载力的计算方法进行了分析，编制了计算图表，供设计者直接查用．该法计算简便、速度快、精度高，有一定的实用价值．     

Ecological effects of climate fluctuations

Climate influences a variety of ecological processes. These effects operate through local weather parameters such as temperature, wind, rain, snow, and ocean currents, as well as interactions among these. In the temperate zone, local variations in weather are often coupled over large geographic areas through the transient behavior of atmospheric planetary-scale waves. These variations drive temporally and spatially averaged exchanges of heat, momentum, and water vapor that ultimately determine growth, recruitment, and migration patterns. Recently, there have been several studies of the impact of large-scale climatic forcing on ecological systems. We review how two of the best-known climate phenomena-the North Atlantic Oscillation and the El Ni?o-Southern Oscillation-affect ecological patterns and processes in both marine and terrestrial systems.     

春小麦杂交组合配制和基因型差异对花培的影响

选用春小麦不同基因型F1代进行花药培养，结果表明，不同基因型的花药培养力差异很大，这与亲本来源、亲本的配合力等因素有关，对花培的诱导效果具有明显的影响。     

豇豆采后保鲜技术的研究

研究表明，豇豆采后１８天不同温度下呼吸率的变化符合菜豆等食用嫩菜的豆类蔬菜的一般规律，在１０，７．５，５，０℃的不同贮藏条件下，以５－０℃的测评效果最好，０℃下贮藏１２天的处理无寒害症状。     

Causes of Decadal Climate Variability over the North Pacific and North America

The cause of decadal climate variability over the North Pacific Ocean and North America is investigated by the analysis of data from a multidecadal integration with a state-of-the-art coupled ocean-atmosphere model and observations. About one-third of the low-frequency climate variability in the region of interest can be attributed to a cycle involving unstable air-sea interactions between the subtropical gyre circulation in the North Pacific and the Aleutian low-pressure system. The existence of this cycle provides a basis for long-range climate forecasting over the western United States at decadal time scales.