Southern Ocean iron enrichment experiment: carbon cycling in high- and low-Si waters

The availability of iron is known to exert a controlling influence on biological productivity in surface waters over large areas of the ocean and may have been an important factor in the variation of the concentration of atmospheric carbon dioxide over glacial cycles. The effect of iron in the Southern Ocean is particularly important because of its large area and abundant nitrate, yet iron-enhanced growth of phytoplankton may be differentially expressed between waters with high silicic acid in the south and low silicic acid in the north, where diatom growth may be limited by both silicic acid and iron. Two mesoscale experiments, designed to investigate the effects of iron enrichment in regions with high and low concentrations of silicic acid, were performed in the Southern Ocean. These experiments demonstrate iron's pivotal role in controlling carbon uptake and regulating atmospheric partial pressure of carbon dioxide.     

中国水稻植保机械现状与发展趋势

植保作业是水稻生产过程中必不可少的环节,提高水稻植保机械化水平,对降低稻田农药的用量,增强突发性爆发性病虫害防控能力,缓解农村劳动力短缺,实现农业可持续发展具有重要意义。从目前常见的人力施药器械入手,对水稻生产中的小型动力植保机械尧大中型动力植保机械和航空植保机械的应用现状及存在问题进行了详细阐述。在分析中国水稻植保机械发展现状的基础上,探讨了现代农业生产中对研究开发用于稻田农药高效精确喷施新方法和新工具的迫切需求,指出未来水稻植保机械主要朝着精准施药和高效施药两个方向发展。最后,从拓宽单次喷施作业的覆盖范围、加强稻田农药喷施作业方法创新和大力推进航空植保技术的应用等方面给出了促进我国水稻植保机械化进一步发展的建议。     

Invasion biology of the cotton mealybug,Phenacoccus solenopsis Tinsley: Current knowledge and future directions

The cotton mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae), which is native to North America, emerged as a major invasive insect pest of multiple crops in Asia at the beginning of the 21st century. Considering the economic significance of this insect and its rapid worldwide spread, we examined the possible factors driving its invasions. In this paper, we summarize the life history traits of P. solenopsis conceivably related to population development in invaded regions; these traits include its use of diverse host plants, reproductive capacity and mode, adaptation to temperature, response to food shortage, and insecticidal resistance. Then, focusing on the multiple trophic interactions that may promote or hinder invasion, we review the mutualistic relationship of this mealybug with ants and predation and parasitism by natural enemies. Finally, we suggest topics for future research and provide our perspective on the biological invasions of this mealybug. We speculate that specific biological factors associated with this mealybug, particularly its wide host range, high reproductive potential, evolved changes in life history traits, and mutualism with ants have played important roles in its invasions, allowing this pest to become established and rapidly increase its population upon its introduction into new regions.     

荔枝龙眼生产机械化现状与发展趋势

荔枝、龙眼生产机械化的普及对于提高果园生产率、加强环境可持续性和增加果农收人有重要的积极意义.根据产业经济发展的需求,以灌溉、施肥、喷药、修Q和采收等生产环节为主,研究了国内外生产设施与机械装备的应用现状,并探讨了技术发展趋势.     

The rural crisis in Minnesota: Identifying social and economic vulnerability and new directions for the future

The rural crisis of the 1980s is described in terms of the economic and social vulnerability of rural farm areas. The crisis is shown spreading from farms through families to rural communities, schools, churches, counties and beyond. Rural communities are shown to be undergoing dramatic and non-cyclical change. Criteria are defined to identify rural counties vulnerable to further economic losses and include: dependence on agriculture for jobs, inadequate off farm income, population losses, declines in residential and commercial property value, and county fiscal crises due to loss of the tax base, delinquincies, and additional federal and state program changes and cutbacks. Social and economic distress are so extensive as to overwhelm conventional emergency intervention efforts to provide food, shelter, access to health care, and professional counseling. Peer support programs have been found to be effective at reaching farm families and helping them seek out the assistance of farm financial advisors, counselors, food shelves, and public assistance. Emerging attempts to link politically contending parties are discussed, specifically the Reinvest in Minnesota Coalition and the Rural Strategy Task Force consisting of major farm, church, and lending organizations. A strategy process and stakeholder analysis for local communities are presented together with recommendations for action that include creating a rural trend watch capability.     

面向资源认知变化的耕地评价研究进展与展望

科学的耕地评价是耕地合理开发、利用、保护的前提,耕地资源认知的深化引领耕地评价研究发展。为明晰耕地评价研究的发展历程、热点动态和未来前景,系统梳理1949—2023年引领耕地资源认知变化的理念、事件和政策,探讨耕地资源认知发展的阶段性特征,借助文献调查、文献计量分析、理论分析等方法,对不同阶段耕地评价研究的主要内容、政策支撑、技术方法与代表成果等进行总结,并提出面向新时期社会发展需求的耕地评价研究展望与关键问题。研究表明：1）耕地资源认知按时间顺序可划分为资源本体、资源平衡体和资源综合体3个阶段,认知对象由耕地数量单一维度向耕地数量与质量、数量-质量-生态、实体耕地与虚拟耕地等多维度转变,研究范围也由宜耕地、耕地等实体资源向近远程耦合框架下的全球虚拟耕地拓展;2）各阶段耕地评价的研究重点围绕耕地数量、耕地质量和耕地综合利用展开。在资源本体阶段,侧重土地开发适宜性评价,关注本底要素宜耕性;在资源平衡体阶段,注重耕地质量提升,对耕地资源的可持续利用潜力进行评价。在资源综合体阶段,评价对象向全球粮食贸易中的虚拟耕地拓展,评价内容关注耕地多功能及功能间权衡与协同关系。因此,未来耕地评价的研究内容需适应新时代发展的现实需求,耕地本体评价需兼顾实体和价值量,耕地质量评价需匹配人类福祉需求,耕地综合评价需考虑多元对象和指标。在评价理论与方法层面应加强学科交叉融合,充分利用新调查监测手段,丰富精细化耕地资源数据,为进一步拓展资源认知、丰富评价范式、优化耕地保护制度等提供支撑。     

高校学院资料室的体制改革和发展方向探析

通过对国内院(所)资料室现状、优势和不足的分析以及国内外高校图书馆建制情况的分析,并结合山东大学的实际情况,探讨了资料室体制改革的模式和经验,提出了院(所)资料室通过体制改革的思路和建议。     

Spatial Organization and Time Dependence of Jupiter's Tropospheric Temperatures, 1980-1993

The spatial organization and time dependence of Jupiter's temperatures near 250-millibar pressure were measured through a jovian year by imaging thermal emission at 18 micrometers. The temperature field is influenced by seasonal radiative forcing, and its banded organization is closely correlated with the visible cloud field. Evidence was found for a quasi-periodic oscillation of temperatures in the Equatorial Zone, a correlation between tropospheric and stratospheric waves in the North Equatorial Belt, and slowly moving thermal features in the North and South Equatorial Belts. There appears to be no common relation between temporal changes of temperature and changes in the visual albedo of the various axisymmetric bands.     

University-Industry Interaction Patterns: Past models are analyzed, some recent experiments described, and recommendations for the future given

The nation is entering a period when the R & D output must be increased, probably without major increases in resource allocation. Obviously, in this situation, either efficiency or productivity must be increased. Perhaps one of the most wasteful aspects of the national R & D system (and one that received little attention during the golden era of the 15 percent per year expansion) has been the very weak coupling between the university, on the one hand, and industry (or government), on the other. It is a serious error to allege about such coupling that "it has never worked," that the objectives and reward structures of the institutions are such that it cannot work, and so on. The fact is that coupling has never been tried seriously. History shows that the total dollar effort in research that required coupling or that had coupling as its main objective was on the order of $10 million per year (that is, much less than 0.1 percent of the research money spent on U.S. campuses). At the same time, there is little doubt that the experiments which must and will be tried in the immediate future call for innovations in management and changes in the attitude and structure of many universities. In conversations with administrators who have had experience with such programs, I have found strong suggestions of very mixed responses from the universities. In light of these responses, and if effectiveness is a goal, it would be better for those universities that are more wedded to disciplinary research, to single principal-investigator work, not to participate in these new efforts. We need much greater diversity in the styles of university life, and it would be healthy for the academic enterprise if some universities retained a greater degree of detachment from society, while others consciously decided to interact more with it, through the private sector, and made the changes necessary to do so. If initial funding is restricted to those universities that consider university-industry or university-government research a worthy objective and that have a proven track record and a favorable administrative and reward structure, the new programs may well establish a major new pattern of national R & D.     

Inhibition of protein synthesis: a mechanism for the production of impaired iron absorption

Treatment of rats with cycloheximide results in a defect in intestinal iron transport. A similar defect occurs after the parenteral administration of iron. Under both conditions there is impaired uptake of iron into the mucosal cells as well as defective transfer from the intestinal mucosa. It is suggested that the interference in iron transport may be due to a deficiency of an unidenti-fild carrier Substance.     

Metabolite of (-)-trans-delta 8-tetrahydrocannabinol: identification and synthesis

The major metabolite of (-)-trans-Delta(8)-tetrahydrocannabinol observed in vivo and formed by hepatic microsomes in vitro is 11-hydroxy-trans-Delta(8)-tetrahydrocannabinol. The metabolite was identified spectroscopically and was synthesized from trans-Delta(8)-tetrahydrocannabinol. In tests with rats, the metabolite produced behavioral effects similar to those imparted by Delta(8)- and Delta(9)-tetrahydrocannabinol.     

2003～2005年《情报理论与实践》载文、作者及引文分析

采用定量分析的方法,选取2003～2005年<情报理论与实践>的研究论文539篇,重点从它的载文、作者及引文这三方面进行分析,得出<情报理论与实践>这三年发展的一些规律.