Radiation response of connexin 43-transfected cells in relation to the “contact effect”

Radiation response of connexin 43-transfected cells in relation to the “contact effect”...     

Farmer seed enterprises: A sustainable approach to seed delivery?

A major reason for the low adoption of modern varieties of seed among small-scale farmers in developing countries is the inability of formal, centralized seed production systems to meet their complex and diverse seed requirements. Drawing on experiences in Uganda with the common bean, the paper proposes seed production by farmer seed enterprises (FSEs) as a strategy for meeting dual objectives: to sustainably distribute and promote modern crop varieties and to establish a regular source of clean seed of either local or modern varieties. It reports on lessons learned from the Ugandan experience and offers a conceptual framework and guidelines for establishing economically and institutionally sustainable FSEs. While FSEs offer a potentially sustainable solution to the problem of seed supply, the challenge of implementing and scaling up this approach in eastern and southern Africa remains formidable. Collaborative linkages need to be fostered between farmers, researchers, agro-enterprise specialists, NGOs, and the formal seed industry. Seed policy reforms need to be implemented and more client-oriented research systems must be institutionalized.     

水稻不育系“中1A”和“春江12A”

中国农科院水稻所主持完成的研究项目“杂交稻野败型三系不育系‘中1A’”和“早花时矮秆晚粳不育系‘春江12A’选育及利用”通过了浙江省科技厅组织的专家鉴定。不育系“中1A”株型紧凑,剑叶挺直,育性稳定,不育株率100%,花粉败育率100%,其中典败率达98.11%,套袋自交结实率为0.     

Species Concepts as Applied to the Whitefly Bemisia tabaci Systematics: How Many Species Are There?

The worldwide distribution and extensive genetic diversity of the whitefly, Bemisia tabaci, has long been recognized. However, the levels of separation within B. tabaci and the nomenclature of the various genetic groups have been a subject of debate. Recent phylogenetic analyses indicate that B. tabaci is a complex composed of >28 morphologically indistinguishable species. In this article, we first review the debate and difficulties associated with B. tabaci's taxonomy and systematics, and argue for the need to apply the biological species concept in order to elucidate B. tabaci's systematics. We summarize the accumulated genetic and behavioural data on reproductive incompatibilities evident amongst phylogenetic mtCOI groups of B. tabaci. Crossing studies have been conducted with 14 of the 28 putative species covering 54 reciprocal inter-species pairs, and observations on mating behaviour have been conducted for seven species pairs. Data from both crossing trials and behavioural observations indicate a consistent pattern of reproductive isolation among the putative species. We then discuss the technical and conceptual complexities associated with crossing experiments and behavioural observations designed to reveal reproductive incompatibility. Finally, we elaborate on a strategy for further clarifying the pattern of reproductive isolation between B. tabaci groups and propose future research directions on the systematics of this complex.     

From “Food from Nowhere” to “Food from Here:” changing producer–consumer relations in Austria

The notion of a “third food regime” implies simultaneous processes of further global concentration and integration and at the same time resistance through new emerging producer–consumer relations. This paper examines these processes by looking at Austria over the last 30 years. While direct producer–consumer cooperatives established at an early point, today forms of community supported agriculture (CSA) are rare. This paper explains this by identifying a shift of the entire food system from “food from nowhere” to “food from here.” The account follows the early emergence of alternative food networks through the political appeal to consumer patriotism in connection with Austria joining the EU, to a sustained positioning of retail chains with regional and national food products. The paper argues that this satisfies the needs of a large proportion of consumers and discourages the emergence of new food initiatives. The paper follows the development of different approaches and their transformations until today. Thus a picture evolves of changing, and partly progressing consumer–producer relations in response to wider societal and political transformation processes. The results explain why the movement towards CSA is currently weak in Austria, but demonstrate at the same time how alternative food networks may contribute to a transformation of the food system.     

Phytoextraction：A Cost-effective Approach to Metal-contaminated Soils

This paper will review the topic of phytoextraction,a major approach of phytoremediation, by clarifying the roles of hyperaccumulators, bio-mechanisms involved, issues regarding contaminant uptake, artificial chelation, genetic selection, and cultivation. The paper will also address the practical issues and the regulatory context of this emerging technology and briefly discuss avenues for future research.     

高台:“三变”带来“三美”

正在湖北农垦草埠湖农场高台队,绿树掩映、鸟语花香,一排排、一幢幢龙脊凤尾、青瓦白墙、装饰崭新的房屋映入眼帘,这里绿树成荫、风景如画,置身其中,不禁让人想起"春游芳草地、夏赏绿荷池、秋饮桂花菊、冬吟白雪诗"的高远意境;它所散发的独特魅力,为我们勾勒出一幅幅恬静清馨的田园诗画。高台队地处长江支流沮漳河中游东岸,位于草埠湖农场镇头山北郊,全队面积7.7平方公里,耕地面积6763亩、人口1163人。近几年来,高台队以村     

张春华:“门外汉”到“土专家”

正冬日的清晨格外寒冷,特别是海拔400多米的浙江省青田县瓯南街道平风寨村。在平风寨春华家庭农场,6名工人正忙着为杨梅树搭建大棚,近2个月时间里,50多棵杨梅树陆续被裹上了一层暖和的"被子"。"山上早晚温差大,如果不及时做好防护措施,杨梅树很可能会冻坏。"为了赶进度,农场负责人张春华一大早就来到基地忙活起大棚的搭建作业。张春华原本在江苏从事蛋糕生意,多年的外出闯荡让他     

ARCHAEOLOGY: Arizona to Take High Road to Preservation?

State transportation officials have agreed to weigh a proposal to set aside a scientifically valuable parcel of a federal highway project for future research rather than excavating it and selling it to the highest bidder. Should it proceed, Arizona could set a new standard of stewardship for government agencies that determine the fate of ancient relics.     

“灭螨A烟雾剂”的研究

“灭螨 A 烟雾剂”系采取由蜂箱外向蜂群内喷烟治螨,因此不开箱,不提脾,操作简便.工效高。它对蜜蜂安全,灭螨效果达74.7～100%。“灭螨 A 烟雾剂”与“杀螨剂一号”相比,小蜂螨的落螨数两者无显著差异,防治大蜂螨后者效果较好,但前者比后者提高工效25～30倍。与“Folbex VA”烟雾剂比较,大蜂螨的落螨数无显著差异,小蜂螨的落螨数差异显著,“灭螨 A 烟雾刘”明显优于“Folbex VA”。