542 research outputs found

    Metabolism and Vitamin A

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    The following determinations were made on urines of rats receiving a control diet and a diet lacking vitamin A: volume, specific gravity, acidity, ammonia, urea, total N, uric acid, creatin, creatinine, total solids, albumin and sugar. The volume, specific gravity, total solids, acidity and ammonia were greater on the control diet. The animals on the deficient diet excreted a much larger percentage of their nitrogen in the form of urea than the animals on the complete ration. Uric acid, creatine and creatinine did not vary. Sugar was not found. Albumin was found in both cases, and appears to be a normal constituent of the urine of the rat

    Vicious and Virtuous Cycles and the Role of External Non-government Actors in Community Forestry in Oaxaca and Michoacán, Mexico

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    Community forestry offers potential for socioeconomic benefits while maintaining ecosystem services. In Mexico, government and donor efforts to develop this sector focus on issues within forest communities. Often overlooked are effects of external non-government actors (NGOs and foresters) as links or barriers between communities and funding, capacity building, and technical support. To analyze the role of these actors, I analyze household survey and interview data from 11 communities with varying levels of vertical integration of forestry production in states with divergent records of community forestry, Oaxaca and Michoacán. Results suggest that strong community governance is necessary but not sufficient for vertical integration, and strong interactions with non-government actors are critical. These actors, operating within the existing framework of government regulations, have a range of incentives for engaging communities. Availability of these actors motivated by concern for community capacity instead of timber income may be a determinant of community forestry development

    Calorie restriction does not elicit a robust extension of replicative lifespan in Saccharomyces cerevisiae

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    Calorie restriction (CR) is often described as the most robust manner to extend lifespan in a large variety of organisms. Hence, considerable research effort is directed toward understanding the mechanisms underlying CR, especially in the yeast Saccharomyces cerevisiae. However, the effect of CR on lifespan has never been systematically reviewed in this organism. Here, we performed a meta-analysis of replicative lifespan (RLS) data published in more than 40 different papers. Our analysis revealed that there is significant variation in the reported RLS data, which appears to be mainly due to the low number of cells analyzed per experiment. Furthermore, we found that the RLS measured at 2% (wt/vol) glucose in CR experiments is partly biased toward shorter lifespans compared with identical lifespan measurements from other studies. Excluding the 2% (wt/vol) glucose experiments from CR experiments, we determined that the average RLS of the yeast strains BY4741 and BY4742 is 25.9 buds at 2% (wt/vol) glucose and 30.2 buds under CR conditions. RLS measurements with a microfluidic dissection platform produced identical RLS data at 2% (wt/vol) glucose. However, CR conditions did not induce lifespan extension. As we excluded obvious methodological differences, such as temperature and medium, as causes, we conclude that subtle method-specific factors are crucial to induce lifespan extension under CR conditions in S. cerevisiae

    Understanding Social Resilience in the Maine Lobster Industry

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    The Maine lobster Homarus americanus fishery is considered one of the most successful fisheries in the world due in part to its unique comanagement system, the conservation ethic of the harvesters, and the ability of the industry to respond to crises and solve collective-action problems. However, recent threats raise the question whether the industry will be able to respond to future threats as successfully as it has to ones in the past or whether it is now less resilient and can no longer adequately respond to threats. Through ethnographic research and oral histories with fishermen, we examined the current level of social resilience in the lobster fishery. We concentrated on recent threats to the industry and the ways in which it has responded to them, focusing on three situations: a price drop beginning in 2008, a recovery in 2010–2011, and a second collapse of prices in 2012. In addition, we considered other environmental and regulatory concerns identified by fishermen. We found that the industry is not responding effectively to recent threats and identified factors that might explain the level of social resilience in the fishery

    Beyond property: Rural politics and land-use change in the Colombian sugarcane landscape

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    Analysing the sugarcane landscape in the flat valley of the Cauca River (Colombia) reveals that agricultural industrialization in the region required the concentration of land use by regional industrialists and the corresponding exclusion of landowners and poor peasants from territorial decision-making processes. The analytical lens used in this article, based on the use and control over land and land-based natural commons, allows for the characterization of three periods in a non-linear process of articulation and dispute between poor peasant and capitalist agents in the expansion of the sugarcane monoculture during the 20th century. The different constellations of social agents, governmental nexus, and capital enclosures have enacted through mechanisms that, beyond concentrating land property, have managed to deprive rural ethnic communities from their cultural and environmental heritage, traditional economies, and possible futures.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151270/1/joac12332_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151270/2/joac12332.pd
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