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排序方式: 共有646条查询结果,搜索用时 93 毫秒
181.
Bovine Respiratory Disease: Its Radiological Features 总被引:1,自引:0,他引:1
182.
183.
Robin Holmes John W. Hayes Weimin Jiang Aaron Quarterman Lawson N. Davey 《Ecology of Freshwater Fish》2014,23(4):631-643
We investigated juvenile brown trout migration and mortality in a headwater tributary of the Motueka River, New Zealand, by tracking 1000 young‐of‐the‐year passive integrated transponder (PIT) tagged fish over autumn to summer to (i) partition total loss into emigration and mortality and (ii) determine the influence of season and flow on emigration. Fish were tracked using mobile and fixed PIT tag readers. Of the 1000 fish tagged, 173 remained within the Rainy River; emigration contributed 60% and mortality 29% to loss. Only 11% of fish tagged in autumn were predicted to remain in the upper reaches of the stream by early summer, and this agreed with density data collected in a parallel study. We identified a two‐phase downstream migration pattern with early movement of large young‐of‐the‐year fish in autumn (mainly during floods). This was followed by another substantial period of movement in spring (during floods and lower flows) by fish that were initially smaller at the time of PIT tagging. The management implications for damming and fish screening in headwater tributaries are discussed. 相似文献
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185.
Saline washings obtained in vivo from the lung of young calves produce pulmonary hypertension upon intrayascular (systemic or pulmonary) injection into either the dog or the calf. This pulmonary hypertension is produced by vasoconstriction of small, precapillary pulmonary vessels. The active agent, pulmonary arterial constrictor substance, differs chemically and physiologically from other substances which have been investigated with respect to vasomotor activity in the pulmonary circulation. Although the chemical nature of the active agent is not known it appears to have a relatively large molecular weight. Whether this agent plays a role in the physiological regulation of the pulmonary circulation is not known. 相似文献
186.
Yin H Slusky JS Berger BW Walters RS Vilaire G Litvinov RI Lear JD Caputo GA Bennett JS DeGrado WF 《Science (New York, N.Y.)》2007,315(5820):1817-1822
A variety of methods exist for the design or selection of antibodies and other proteins that recognize the water-soluble regions of proteins; however, companion methods for targeting transmembrane (TM) regions are not available. Here, we describe a method for the computational design of peptides that target TM helices in a sequence-specific manner. To illustrate the method, peptides were designed that specifically recognize the TM helices of two closely related integrins (alphaIIbbeta3 and alphavbeta3) in micelles, bacterial membranes, and mammalian cells. These data show that sequence-specific recognition of helices in TM proteins can be achieved through optimization of the geometric complementarity of the target-host complex. 相似文献
187.
Sonja Brodt Gail Feenstra Robin Kozloff Karen Klonsky Laura Tourte 《Agriculture and Human Values》2006,23(1):75-88
While questions about the environmental sustainability of contemporary farming practices and the socioeconomic viability of
rural communities are attracting increasing attention throughout the US, these two issues are rarely considered together.
This paper explores the current and potential connections between these two aspects of sustainability, using data on community
members’ and farmers’ views of agricultural issues in California’s Central Valley. These views were collected from a series
of individual and group interviews with biologically oriented and conventional farmers as well as community stakeholders.
Local marketing, farmland preservation, and perceptions of sustainable agriculture comprised the primary topics of discussion.
The mixed results indicate that, while many farmers and community members have a strong interest in these topics, sustainable
community development and the use of sustainable farming practices are seldom explicitly linked. On the other hand, many separate
efforts around the Valley to increase local marketing and agritourism, improve public education about agriculture, and organize
grassroots farmland preservation initiatives were documented. We conclude that linking these efforts more explicitly to sustainable
agriculture and promoting more engagement between ecologically oriented farmers and their communities could engender more
economic and political support for these farmers, helping them and their communities to achieve greater sustainability in
the long run.
Sonja Brodt is a former program evaluation specialist with the University of California Integrated Pest Management Program. Her current
research focuses on extension and adoption of integrated pest management strategies by California growers and the impacts
of pesticide safety training programs on farmworkers.
Gail Feenstra is a food systems analyst at the University of California Sustainable Agriculture Research and Education Program (SAREP).
She coordinates SAREP’s Community Development and Public Policy grants program and conducts outreach and education to academic
and community-based groups to build their capacity and leadership skills for developing sustainable community food systems.
Robin Kozloff is a social science researcher and consultant in agricultural and land use policy.
Karen Klonsky is an extension specialist at the University of California at Davis in the Department of Agricultural and Resource Economics.
Her research focuses on the economic viability of organic and sustainable farming systems as well as the evolution of the
organic market.
Laura Tourte is county director and farm advisor at the University of California Cooperative Extension in Santa Cruz County. Her research
and extension activities currently focus on farm management and marketing for small-scale growers. 相似文献
188.
Dennell R 《Science (New York, N.Y.)》2011,331(6024):1532-1533
189.
Robin Jane Roff 《Agriculture and Human Values》2007,24(4):511-522
While the cultivation of genetically modified organisms (GMO) and the spread of genetically engineered (GE) foods has gone
largely unnoticed by the majority of Americans, a growing number of vocal civil society groups are opposing the technology
and with it the entire conventional system of food provision. As with other alternative food movements, non-GMO activists
focus on changing individual consumption habits as the best means of altering the practices of food manufacturers and thereby
what and how food is produced. In this paper I argue that the increasing use of consumerist tactics reflect the neoliberalization
of food activism in the United States – a process that rather than heralding sustainable agricultural and economic futures
may reinforce the status quo. Using the emerging non-GMO movement, and the associated market for non-GMO products, I challenge
the assumptions that consumer sovereignty and freedom of choice will bring about the small-scale, localized alternatives espoused
by activists and scholars in the field. Specifically, I explore three critical limitations of contemporary alternative food
politics. First, the neoliberalization of activism shifts the responsibility for social reforms from the state and manufactures
to individual consumers, bringing with it important social justice implications. Second, focusing on choice opens new spaces
for the profit without seriously threatening contemporary market structures or agro-ecological practices. Third, contemporary
consumerist politics focus on eating right not less and thereby provide few alternatives to the current trends towards convenience
and processed foods.
Robin
Jane Roff
is a PhD Candidate in the Department of Geography at Simon Fraser University, British Columbia, Canada. She received a Bachelors
of Art in Geography and Political Science from the University of Toronto in 2003. Her research focuses on the political-economy
of American food and the dimensions of counter-culture and environmental activism in late capitalist societies. Her dissertation,
which examines on the power and influence of the American anti-biotechnology movement, is currently funded by the Social Science
and Humanities Research Council of Canada. 相似文献
190.