Management Zones Classified With Respect to Drought and Waterlogging     

Sofia Delin  Kerstin Berglund 《Precision Agriculture》2005,6(4):321-340

Within-field variations in potential grain yield may be due to variations in plant available soil water. Different water holding capacities affect yield differently in different years depending on weather. By estimating plant-water availability in different weathers, scenarios could be created of how yield potential and thereby fertilizer demand may vary within fields. To test this, measured cereal grain yields from a dry, a wet and an intermediate year were compared with different soil moisture related variables in a Swedish arable field consisting of clayey and sandy areas. Soil water budget calculations based on weather data and maximum plant available water (PAW), estimated from soil type and rooting data, were used to assess drought. A reasonable correlation between estimated and measured soil moisture was achieved. In the dry year, drought days explained differences in yield between the clayey and the sandy soil, but yield was better explained directly by maximum PAW, elevation, clay content and soil electrical conductivity (SEC). Yield correlated significantly with SEC and elevation within the sandy soil in the dry year and within the clayey soil in the wet year, probably due to water and nitrogen limitation respectively. Dense SEC, elevation and yield data were therefore used to divide the field into management zones representing different risk levels for drought and waterlogging. These could be used as a decision support tool for site-specific N fertilization, since both drought and waterlogging affect N fertilization demand.  相似文献   

Against the neoliberal steamroller? The Biosafety Protocol and the social regulation of agricultural biotechnologies   总被引：1，自引：0，他引：1  

Daniel Lee Kleinman  Abby J. Kinchy 《Agriculture and Human Values》2007,24(2):195-206

Through a discursive and organizational analysis we seek to understand the Biosafety Protocol and the place of socioeconomic regulation of agricultural biotechnology in it. The literature on the Protocol has been fairly extensive, but little of it has explored debates over socioeconomic regulation during the negotiation process or the regulatory requirements specified in the final document. This case is especially important at a time when the spread of neoliberalism is increasingly associated with deregulation, because it sheds light on the conditions under which circumvention of the market is deemed legitimate and socio-economic regulation of agricultural technology is possible. Daniel Lee Kleinman is a professor in the Department of Rural Sociology at the University of Wisconsin, Madison, where he is also affiliated with the Holtz Center for Science and Technology Studies and the Integrated Liberal Studies Program. He is the author and editor of a number of books, including Impure Cultures: University Biology and the World of Commerce (2003). Abby J. Kinchy is a PhD candidate in the Departments of Sociology and Rural Sociology at the University of Wisconsin, Madison. Her current research examines the controversies surrounding the genetic “contamination” of Mexican maize and Canadian canola.  相似文献   

Crystal structure of the eukaryotic 40S ribosomal subunit in complex with initiation factor 1     

Rabl J  Leibundgut M  Ataide SF  Haag A  Ban N 《Science (New York, N.Y.)》2011,331(6018):730-736

Eukaryotic ribosomes are substantially larger and more complex than their bacterial counterparts. Although their core function is conserved, bacterial and eukaryotic protein synthesis differ considerably at the level of initiation. The eukaryotic small ribosomal subunit (40S) plays a central role in this process; it binds initiation factors that facilitate scanning of messenger RNAs and initiation of protein synthesis. We have determined the crystal structure of the Tetrahymena thermophila 40S ribosomal subunit in complex with eukaryotic initiation factor 1 (eIF1) at a resolution of 3.9 angstroms. The structure reveals the fold of the entire 18S ribosomal RNA and of all ribosomal proteins of the 40S subunit, and defines the interactions with eIF1. It provides insights into the eukaryotic-specific aspects of protein synthesis, including the function of eIF1 as well as signaling and regulation mediated by the ribosomal proteins RACK1 and rpS6e.  相似文献   

The ultrasmoothness of diamond-like carbon surfaces     

Moseler M  Gumbsch P  Casiraghi C  Ferrari AC  Robertson J 《Science (New York, N.Y.)》2005,309(5740):1545-1548

The ultrasmoothness of diamond-like carbon coatings is explained by an atomistic/continuum multiscale model. At the atomic scale, carbon ion impacts induce downhill currents in the top layer of a growing film. At the continuum scale, these currents cause a rapid smoothing of initially rough substrates by erosion of hills into neighboring hollows. The predicted surface evolution is in excellent agreement with atomic force microscopy measurements. This mechanism is general, as shown by similar simulations for amorphous silicon. It explains the recently reported smoothing of multilayers and amorphous transition metal oxide films and underlines the general importance of impact-induced downhill currents for ion deposition, polishing, and nanopattering.  相似文献   

Book review     

DOUGLAS H. CONSTANCE 《Agriculture and Human Values》2005,22(2):259-260

  相似文献   

Radar soundings of the subsurface of Mars   总被引：2，自引：0，他引：2  

Picardi G  Plaut JJ  Biccari D  Bombaci O  Calabrese D  Cartacci M  Cicchetti A  Clifford SM  Edenhofer P  Farrell WM  Federico C  Frigeri A  Gurnett DA  Hagfors T  Heggy E  Herique A  Huff RL  Ivanov AB  Johnson WT  Jordan RL  Kirchner DL  Kofman W  Leuschen CJ  Nielsen E  Orosei R  Pettinelli E  Phillips RJ  Plettemeier D  Safaeinili A  Seu R  Stofan ER  Vannaroni G  Watters TR  Zampolini E 《Science (New York, N.Y.)》2005,310(5756):1925-1928

The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.  相似文献   

Is it economically feasible to harvest by management zone?     

Peter R. Tozer  Bindi J. Isbister 《Precision Agriculture》2007,8(3):151-159

The economics of harvesting wheat based on input management zones in the northern wheatbelt of Western Australia was studied using a simulated field of regular dimensions with varying zone sizes and layouts. Fertilizer application rates and crop yield and quality data from field trials of input management were used to estimate the gross crop revenue and harvesting costs from the different field layouts and zone combinations. As a general observation there was no consistency in the results; harvesting by zone generated more gross income in some combinations of field layout and yield quantity scenarios, but not in others. However, there were key factors in determining whether it was profitable to harvest by zone. These were prior knowledge of the potential yield and quality characteristics of grain from each zone in a field, and the layout of zones within a field.  相似文献   

From value to values: sustainable consumption at farmers markets     

Alison Hope Alkon 《Agriculture and Human Values》2008,25(4):487-498

Advocates of environmental sustainability and social justice increasingly pursue their goals through the promotion of so-called “green” products such as locally grown organic produce. While many scholars support this strategy, others criticize it harshly, arguing that environmental degradation and social injustice are inherent results of capitalism and that positive social change must be achieved through collective action. This study draws upon 18 months of ethnographic fieldwork at two farmers markets located in demographically different parts of the San Francisco Bay Area to examine how market managers, vendors, and regular customers negotiate tensions between their economic strategies and environmental sustainability and social justice goals. Managers, vendors, and customers emphasize the ethical rather than financial motivations of their markets through comparisons to capitalist, industrial agriculture and through attention to perceived economic sacrifices made by market vendors. They also portray economic strategies as a pragmatic choice, pointing to failed efforts to achieve justice and sustainability through policy change as well as difficulties funding and sustaining non-profit organizations. While market managers, vendors, and customers deny any difficulties pursuing justice and sustainability through local economics, the need for vendors to sustain their livelihoods does sometimes interfere with their social justice goals. This has consequences for the function of each market.

Alison Hope AlkonEmail:

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Alison Hope Alkon   is a Ph.D. candidate in the Department of Sociology at the University of California, Davis. Her research examines how efforts to create environmental protection and social justice operate in a market context.  相似文献   

Engagement for transformation: Value webs for local food system development   总被引：1，自引：0，他引：1  

Daniel R. Block  Michael Thompson  Jill Euken  Toni Liquori  Frank Fear  Sherill Baldwin 《Agriculture and Human Values》2008,25(3):379-388

Engagement happens when academics and non-academics form partnerships to create mutual understanding, and then take action together. An example is the “value web” work associated with W. K. Kellogg Foundation’s Food Systems Higher Education–Community Partnership. Partners nationally work on local food systems development by building value webs. “Value chains,” a concept with considerable currency in the private sector, involves creating non-hierarchical relationships among otherwise disparate actors and entities to achieve collective common goals. The value web concept is extended herein by separating the values of the web itself, such as the value of collaboration, from values “in” the web, such as credence values associated with a product or service. By sharing and discussing case examples of work underway around the United States, the authors make a case for employing the value webs concept to represent a strategy for local food systems development, specifically, and for higher education–community partnerships, generally.

Daniel R. BlockEmail:

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Daniel R. Block   is an associate professor of geography and coordinator of the Frederick Blum Neighborhood Assistance Center at Chicago State University. His current research focuses on food access issues in urban environments, particularly in Chicago. Michael Thompson   is an assistant professor at Oregon State University, and a Seafood and Fisheries specialist for Oregon Sea Grant Extension. Primary areas of research include fisheries management, seafood quality/handling, and seafood product development. Jill Euken   is an industrial specialist for biobased products for Iowa State University Extension/CIRAS, and deputy director, ISU Bioeconomy Institute. She was part of the steering team for the Iowa Value Chain Partnership for Sustainable Agriculture and led the Bioeconomy Working Group. Toni Liquori   is a nutritionist, teacher and food activist with a long time interest in the design, implementation, and evaluation of school-based intervention programs and coalition building for activism around food related issues, as well as teaching and training in public health. Frank Fear   is senior associate dean, College of Agriculture and Natural Resources; and professor, in the Department of Community, Agriculture, Recreation and Resources Studies; and Senior Outreach Fellow at Michigan State University. He is lead author of Coming to Critical Engagement (University Press of America, 2006), an analysis of the engagement movement in higher education; and recently completed two terms as president of the Greater Lansing Food Bank. Sherill Baldwin   is ecology director at Mercy Center at Madison, Connecticut, a spiritual retreat and conference center. She previously provided consulting services to CitySeed, Inc. in New Haven (CT) and to Frank Fear and the W. K. Kellogg Foundation for a community learning project related to sustainable food systems. She has an MS in Resource Development from Michigan State University and a BA in Solid Waste Management from the University of Massachusetts.  相似文献   

A neutralizing antibody selected from plasma cells that binds to group 1 and group 2 influenza A hemagglutinins   总被引：2，自引：0，他引：2  

Corti D  Voss J  Gamblin SJ  Codoni G  Macagno A  Jarrossay D  Vachieri SG  Pinna D  Minola A  Vanzetta F  Silacci C  Fernandez-Rodriguez BM  Agatic G  Bianchi S  Giacchetto-Sasselli I  Calder L  Sallusto F  Collins P  Haire LF  Temperton N  Langedijk JP  Skehel JJ  Lanzavecchia A 《Science (New York, N.Y.)》2011,333(6044):850-856

The isolation of broadly neutralizing antibodies against influenza A viruses has been a long-sought goal for therapeutic approaches and vaccine design. Using a single-cell culture method for screening large numbers of human plasma cells, we isolated a neutralizing monoclonal antibody that recognized the hemagglutinin (HA) glycoprotein of all 16 subtypes and neutralized both group 1 and group 2 influenza A viruses. Passive transfer of this antibody conferred protection to mice and ferrets. Complexes with HAs from the group 1 H1 and the group 2 H3 subtypes analyzed by x-ray crystallography showed that the antibody bound to a conserved epitope in the F subdomain. This antibody may be used for passive protection and to inform vaccine design because of its broad specificity and neutralization potency.  相似文献