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101.
Persistence of Swidden Cultivation in the Face of Globalization: A Case Study from Communities in Calakmul, Mexico 总被引:1,自引:0,他引:1
Birgit Schmook Nathalie van Vliet Claudia Radel María de Jesús Manzón-Che Susannah McCandless 《Human ecology: an interdisciplinary journal》2013,41(1):93-107
Over the last decades, political, economic and environmental pressures have encouraged changes from swidden to more intensive agricultural practices, resulting in the hypothesis that swidden cultivation systems are disappearing. In Calakmul, southeastern Mexico, communities decreased the area under milpa, the traditional maize swidden system, but a collapse did not occur. To document and explain the persistence of swidden we employ a variety of data: (1) 59 standardized household surveys from 2003 and 2010 in five villages, (2) in-depth interviews in one village, and (3) coupled human–environmental timelines in this same village. Droughts, hurricanes, and remittances were important drivers of decreases in milpa cultivation. Market crop profitability and conservation programs were also reported to affect the area under milpa. Off-farm employment and governmental transfers have tended to stabilize household economies and decrease dependency on agricultural production, but have also allowed households to maintain their milpas for subsistence and cultural reproduction. Findings in Calakmul point to the need to consider swidden as an evolving and active response to changing policy, economic, and environmental conditions. 相似文献
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Although a total ban on the use of TBT coatings is not expected in the short term, there is a growing need for environmentally safe antifouling systems. To assist in the rapid screening of a large number of potential antifouling substances, a method that is simple, efficient and inexpensive is required. The production of byssus threads by the blue mussel, Mytilus edulis, has often been studied for testing the antifouling efficacy of various compounds. The present study reports a new antifouling assay based on the inhibition of purified M. edulis phenoloxidase activity. The method has the advantage of being specific, reliable, sensitive and rapid. 相似文献
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Sabiha Abekhoukh Chris Planque Clémentine Ripoll Paulina Urbaniak Jean-Louis Paul Jean-Maurice Delabar Nathalie Janel 《Molecular neurobiology》2013,47(1):105-116
Hyperhomocysteinemia due to cystathionine beta synthase (CBS) deficiency is associated with diverse brain disease. Whereas the biological actions linking hyperhomocysteinemia to the cognitive dysfunction are not well understood, we tried to establish relationships between hyperhomocysteinemia and alterations of signaling pathways. In the brain of CBS-deficient mice, a murine model of hyperhomocysteinemia, we previously found an activation of extracellular signal-regulated kinase (ERK) pathway and an increase of Dyrk1A, a serine/threonine kinase involved in diverse functions ranging from development and growth to apoptosis. We then investigated the relationship between Dyrk1A and the signaling pathways initiated by receptor tyrosine kinases (RTK), the ERK and PI3K/Akt pathways. We found a significant increase of phospho-ERK, phospho-MEK, and phospho-Akt in the brain of CBS-deficient and Dyrk1a-overexpressing mice. This increase was abolished when CBS-deficient and Dyrk1A-transgenic mice were treated with harmine, an inhibitor of Dyrk1A kinase activity, which emphasizes the role of Dyrk1A activity on ERK and Akt activation. Sprouty 2 protein level, a negative feedback loop modulator that limits the intensity and duration of RTK activation, is decreased in the brain of CBS-deficient mice, but not in the brain of Dyrk1A transgenic mice. Furthermore, a reduced Dyrk1A and Grb2 binding on sprouty 2 and an increased interaction of Dyrk1A with Grb2 were found in the brain of Dyrk1A transgenic mice. The consequence of Dyrk1A overexpression on RTK activation seems to be a decreased interaction of sprouty 2/Grb2. These observations demonstrate ERK and Akt activation induced by Dyrk1A in the brain of hyperhomocysteinemic mice and open new perspectives to understand the basis of the cognitive defects in hyperhomocysteinemia. 相似文献
104.
David Fong Martine Bisson Gino Laberge Stephen McManus Guillaume Grenier Nathalie Faucheux Sophie Roux 《Cellular signalling》2013,25(4):717-728
BMP-9 is a potent osteogenic factor; however, its effects on osteoclasts, the bone-resorbing cells, remain unknown. To determine the effects of BMP-9 on osteoclast formation, activity and survival, we used human cord blood monocytes as osteoclast precursors that form multinucleated osteoclasts in the presence of RANKL and M-CSF in long-term cultures. BMP-9 did not affect osteoclast formation, but adding BMP-9 at the end of the culture period significantly increased bone resorption compared to untreated cultures, and reduced both the rate of apoptosis and caspase-9 activity. BMP-9 also significantly downregulated the expression of pro-apoptotic Bid, but only after RANKL and M-CSF, which are both osteoclast survival factors, had been eliminated from the culture medium. To investigate the mechanisms involved in the effects of BMP-9, we first showed that osteoclasts expressed some BMP receptors, including BMPR-IA, BMPR-IB, ALK1, and BMPR-II. We also found that BMP-9 was able to induce the phosphorylation of Smad-1/5/8 and ERK 1/2 proteins, but did not induce p38 phosphorylation. Finally, knocking down the BMPR-II receptor abrogated the BMP-9-induced ERK-signaling, as well as the increase in bone resorption. In conclusion, these results show for the first time that BMP-9 directly affects human osteoclasts, enhancing bone resorption and protecting osteoclasts against apoptosis. BMP-9 signaling in human osteoclasts involves the canonical Smad-1/5/8 pathway, and the ERK pathway. 相似文献
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Sébastien Besseau Franziska Kellner Arnaud Lanoue Antje M.K. Thamm Vonny Salim Bernd Schneider Fernando Geu-Flores René H?fer Grégory Guirimand Anthony Guihur Audrey Oudin Ga?lle Glevarec Emilien Foureau Nicolas Papon Marc Clastre Nathalie Giglioli-Guivarc’h Benoit St-Pierre Danièle Werck-Reichhart Vincent Burlat Vincenzo De Luca Sarah E. O’Connor Vincent Courdavault 《Plant physiology》2013,163(4):1792-1803
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