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251.
Asplund J  Solhaug KA  Gauslaa Y 《Ecology》2010,91(10):3100-3105
The optimal defense theory (ODT) deals with defensive compounds improving fitness of a particular organism. It predicts that these compounds are allocated in proportion to the risk for a specific plant tissue being attacked and this tissue's value for plant fitness. As the benefit of defense cannot easily be measured in plants, the empirical evidence for ODT is limited. However, lichens are unique in the sense that their carbon-based secondary compounds can nondestructively be removed or reduced in concentration by acetone rinsing. By using such an extraction protocol, which is lethal to plants, we have tested the ODT by studying lichens instead of plants as photosynthetically active organisms. Prior to acetone rinsing, we found five times higher concentration of meta-scrobiculin in the reproductive parts (soralia) of Lobaria scrobiculata compared to somatic parts of this foliose epiphytic lichen species. At this stage, the lichen-feeding snail Cochlodina laminata avoided the soralia. However, after removal of secondary compounds, the snail instead preferred the soralia. In this way, we have successfully shown that grazing pattern inversely reflects the partitioning of the secondary compounds that have a documented deterring effect. Thus our study provides strong and novel evidence for the ODT.  相似文献   
252.
Metal concentrations were determined in water, sediment, and freshwater fish samples (Squalus cephalus, Barbus esocinus, and Barbus xanthopterus) collected from Karakaya Dam Lake, Turkey, to estimate the risk of human consumption and pollution. Metal concentrations differed between the species (p??Zn?=?Cu in water and Fe?>?Zn?>?Mn?>?Ni?>?Cu in sediment. In general, the accumulation order of elements in the tissues all of the species sampled were found as Fe?>?Zn?>?Se?>?Mn?>?Cu?>?Ni?>?Cd in muscle, Zn?>?Fe?>?Mn?>?Se?>?Cu?>?Ni?>?Cd in gills, Fe?>?Zn?>?Se?>?Mn?>?Cu?>?Ni?>?Cd in liver and gonad, and Zn?>?Fe?>?Cu?>?Mn?>?Se?>?Ni?>?Cd in kidney. It was concluded that the fish from the dam lake are not heavily burdened with metals, but they should be controlled periodically to avoid excessive intake of trace metals by humans, and to monitoring the pollution of aquatic environment.  相似文献   
253.
The failure of food security and livelihood interventions to adapt to conflict settings remains a key challenge in humanitarian responses to protracted crises. This paper proposes a social capital analysis to address this policy gap, adding a political economy dimension on food security and conflict to the actor‐based livelihood framework. A case study of three hillsides in north Burundi provides an ethnographic basis for this hypothesis. While relying on a theoretical framework in which different combinations of social capital (bonding, bridging, and linking) account for a diverse range of outcomes, the findings offer empirical insights into how social capital portfolios adapt to a protracted crisis. It is argued that these social capital adaptations have the effect of changing livelihood policies, institutions, and processes (PIPs), and clarify the impact of the distribution of power and powerlessness on food security issues. In addition, they represent a solid way of integrating political economy concerns into the livelihood framework.  相似文献   
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Government administered protected areas (PAs) have dominated conservation strategies, discourse, and research, yet private actors are increasingly managing land for conservation. Little is known about the social and environmental outcomes of these privately protected areas (PPAs). We searched the global literature in English on PPAs and their environmental and social outcomes and identified 412 articles suitable for inclusion. Research on PPAs was geographically skewed; more studies occurred in the United States. Environmental outcomes of PPAs were mostly positive (89%), but social outcomes of PPAs were reported less (12% of all studies), and these outcomes were more mixed (65% positive). Private protected areas increased the number or extent of ecosystems, ecoregions, or species covered by PAs (representativeness) and PA network connectivity and effectively reduced deforestation and restored degraded lands. Few PPA owners reported negative social outcomes, experienced improved social capital, increased property value, or a reduction in taxes. Local communities benefited from increased employment, training, and community-wide development (e.g., building of schools), but they reported reduced social capital and no significant difference to household income. The causal mechanisms through which PPAs influence social and environmental outcomes remain unclear, as does how political, economic, and social contexts shape these mechanisms. Future research should widen the geographical scope and diversify the types of PPAs studied and focus on determining the casual mechanisms through which PPA outcomes occur in different contexts. We propose an assessment framework that could be adopted to facilitate this process.  相似文献   
257.
Prenatal diagnosis of congenital atresia of the larynx is difficult but is possible by the findings of increased lung echogenicity and size coexisting with fetal ascites in ultrasonography. Sonographic findings may not always be typical. We report on a case of congenital laryngeal atresia diagnosed prenatally by the findings of fetal hydrops and hyperechogenic lungs. Our case presented with oligohydramnios. We also review syndromes that demonstrate laryngeal anomalies. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
258.
A “multi-pollutant exposure programme” reflecting the new pollution situation where SO2 is no longer the dominating pollutant has been performed by the International Co-operative Programme on Effects on Materials, including Historic and Cultural Monuments (ICP Materials) within the activities of the Convention on Long-range Transboundary Air Pollution. The main results obtained in the period 1997–2003 are summarised. Dose-response functions are presented for carbon steel, zinc, copper, bronze and limestone. Parameters involved in the functions include besides SO2 and pH, which were included in the previously developed functions from ICP Materials, also the effect of particulate matter and HNO3.  相似文献   
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Experiments were conducted at the Asp? Hard Rock Laboratory in order to improve the understanding of radionuclide retention properties of fractured crystalline bedrock in the 10-100 m scale (TRUE Block Scale Project, jointly funded by ANDRA, ENRESA, Nirex, JNC, Posiva and SKB). A series of tracer experiments were performed using sorbing tracers in three different flow paths. The different flow paths had Euclidian lengths of 14, 17 and 33 m, respectively, and one to three water conducting structures. Four tests were performed using different cocktails made up of radioactive sorbing tracers (22,24Na+, 42K+, 47Ca2+, 85Sr2+, 83,86Rb+, 131,133Ba2+ and 134,137Cs+). For each tracer injection, the breakthrough of sorbing tracers was compared to the breakthrough of a conservative tracer, 82Br-, 131I-, HTO and 186ReO4-, respectively. In the two longer flow paths, no breakthrough of 83Rb+ and 137Cs+ was observed after 8 months of pumping. Selected tracer tests were subject to basic modelling in which a one-dimensional (1D) advection-dispersion model, including surface sorption, and an unlimited matrix diffusion were used for the interpretation of the results. The results of the modelling indicated that there is a slightly higher mass transfer into a highly porous material in the block-scale experiment compared with in situ experiments performed over shorter distances and significantly higher than what would have been expected from laboratory data obtained from studies of the interactions in nonaltered intact rock.  相似文献   
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