Analysing disease incidence data from designed experiments by generalized linear mixed models

As a result of aggregation or clustering of sampling units, disease incidence data from designed experiments frequently show overdispersion relative to the binomial distribution. This paper discusses generalized linear mixed models (GLMM) suitable for analysing overdispersed disease incidence data. The methods are exemplified using data from a randomized complete block experiment on the incidence of downy mildew ( Plasmopara viticola ) of grape ( Vitis lambrusca ). Hints are given regarding implementation of the methods using the %GLIMMIX macro for the SAS system.     

Economically Important Leatherjackets of Grassland and Cereals: Biology, Impact and Control

Despite the large number of cranefly species only two have been convincingly associated with crop damage. The larvae of Tipula paludosa are commonly found as pests in both grassland and spring cereals whereas those of T. oleracea are only established as pests of winter cereals following crops of oilseed rape in the rotation. The latter, however, is probably the species involved in opportunistic situations involving various minor crops. These epidemiological contrasts are attributable to differences in the morphology and behaviour of the adults of the two species in relation to crop rotations. Larvae are sufficiently similar as to cause confusion in identification and this has hampered development of a clear picture of the ecology of the two species. Little is known about the distribution of T. oleracea larvae but T. paludosa larvae are largely regulated by climatic factors, especially rainfall, although the operation of these varies across the distribution range. Many natural enemies have been identified but a commercially viable control method using them has not yet been developed for either species. Control of T. paludosa is relatively easy using broad-spectrum insecticides but inconsistent kills have been observed with winter pesticide applications against T. oleracea. Determination of those fields requiring applications in advance of the damage remains the major problem, especially in grassland and winter cereals, to be resolved for the management of leatherjacket pests.     

托克托县土地资源开发利用回顾与展望

托克托县土地资源的开发利用经历了从春秋战国至隋代和唐朝至元朝的两次大的兴旺至衰落阶段,又经受了明、清和中华民国时期的大面积军垦。新中国成立后,尤其是八十年代初以来,土地资源在广度和深度上得到进一步开发。目前,政府宏观调控,土地利用结构进一步趋向合理,提倡土地资源集约经营,为下个世纪社会经济的持续发展创造了良好的土地条件。     

左翼电影的艺术特征、叙事策略的市场化转轨及其与新市民电影的内在联系

左翼电影出现于1932年,到1935年,其最高代表作品《风云儿女》表明,中国左翼电影已经从整体上融宣传性、思想性和艺术性于一体,并达到了完美的统一;影片在都市意识和电影市场意识规范下的叙事策略,既是出品方电通影片公司的制片路线从左翼电影向新市民电影转化的基础,也是一年之后新市民电影全面取代左翼电影成为唯一的中国主流电影的开始,而二者间内在的文化逻辑关联值得注意。     

Relationships between morphological traits and resistance to pine wood nematode in two Japanese pines

It has been suggested that certain morphological traits of Japanese pines function as resistance factors against the pine wood nematode (PWN), Bursaphelenchus xylophilus. The aim of this study was to verify this concept, and to determine the relationships between traits and resistance at both the individual and family levels. Relationships between survival rate and morphological traits of Pinus densiflora and Pinus thunbergii were studied after inoculation with PWN. Morphometric parameters used were height, basal diameter of the axis, and the number of branches from the axis. Three indices of relationships were analysed: (1) among individuals within a family (survival difference between smaller and larger morphometric populations within each family); (2) among individuals (correlation between each morphometric average and survival rate in quintile populations of all subjects within each pine species based on the order of morphometric values); and (3) among families (correlation between each morphometric average and survival rate in the family). Both significant and non-significant differences were detected within a family, indicating a need for macro techniques. Among individuals, a thicker axis and more branches were correlated with increased survival, indicating that they are resistance factors. However, these correlations were not significant among different families. These results indicate that morphological traits cannot be used to evaluate resistance at a family level, even if they are significant at an individual level. Further studies on traits associated with resistance should be conducted at a family rather than an individual level, to breed for Japanese pines with resistance to PWN.

家蚕蛾黄翅的遗传分析与黄血基因的多效作用

在保存家蚕突变基因资源过程中调查发现：黄血蚕蛾翅在羽化之初呈鲜黄色,白血蚕均不然。通过与白血蚕（非黄翅）和黄血抑制基因（I）进行杂交试验,分析黄翅的遗传规律,结合普查家蚕突变系统蛾翅色性状,证明黄翅性状与幼虫黄脚一样,为黄血基因支配。进而记录了因黄血基因的多效作用在卵、幼虫、茧、成虫各阶段表现的形态特征。     

鸡的铜绿假单胞菌病的研究

１９９８年６－１１月天津武清,蓟县,河北玉田等地出现一种以眼睑肿胀,流泪,瞎眼及喙端,眼,践爪结痂为特征的鸡传染病。病鸡主要为３０－６０日龄。经鼻感染３０日龄鸡复制出了与自然病例相同的临床表现,并分离到接种菌。对分离菌的系统鉴定表明所分离的４株菌均为铜绿假单胞菌。     

黄佤森林崇拜的生态人类学解读

用生态人类学的观点解读黄佤的森林崇拜，可以看到黄佤森林崇拜反映了人与自然和谐发展的生态文化观，对当地生态环境的保护以及提高社区成员的生态保护意识起了重要作用。对黄佤森林崇拜所蕴含的生态保护思想进行挖掘和整理，能为解决当今的生态问题提供一些启示。     

秃杉种质资源迁地保存育苗技术研究

总结研究了13a来在地处亚热带在江苏省宁镇丘陵地区引种原产云贵高原、鄂西山地的珍稀树种秃杉获得在播种育苗与无性繁殖技术成果。该项 成果认为采用氧化剂消毒浸种侵芽,适时防治幼苗猝倒病,适度遮荫保湿,当年冬季防寒保苗等组装技术,可使每公斤种子产秃杉合格苗2．20万－5．60万株,1年生苗安全越冬;采用砻糠灰作基质,用KMnO4液浸条,在秋冬季扦插,生根率达41．3％－54．4％;用电子叶间隙喷雾,以珍珠岩作基质,或在日光温室内用塑料薄膜封闭保温,用KMnO4液浸条等技术,可使插条生根率达72．6％和76．1％。     

自制包膜复合肥的养分释放特征及其对番茄光合作用的影响

氮肥施用量大,氮素利用效率低一直是困扰我国农业生产的突出问题。如何提高氮肥利用效率、减少因过量施用氮肥而引起的环境污染问题是目前国内外肥料研究的热点问题。通过水培和盆栽试验,研究了几种自制包膜复合肥的氮释放速率及其对番茄光合作用的影响。结果表明:聚合物包膜的复合肥能明显克服未包膜复合肥破裂释放模式的缺点,使养分释放更加平缓;聚合物包膜的膜厚度对肥料的养分释放期起决定性作用,养分初期溶出率随着膜厚度的增加而降低,养分释放期相对延长;增加抑制剂可以明显降低复合肥的氮释放速率。对比盆栽试验表明:随着包膜厚度的增加,番茄叶片的净光合作用、蒸腾速率和叶绿素含量明显增加;包膜中加入抑制剂也可以提高番茄叶片的净光合作用、蒸腾速率和叶绿素含量,各处理之间呈显著水平,说明对复合肥进行包膜可以降低氮的释放速率,提高番茄叶片的光能利用效率。