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51.

The spatial distribution of trace elements in surface sediments of the Hooghly estuary was studied over the monsoons in 2014–2017. As, Cd, Ni, Pb and U were two- to sixteen-fold the crust means with increasing levels toward the estuary, with Ni peak during the post-monsoon. Pearson’s correlation matrix, cluster analysis, enrichment factors and pollution index revealed the anthropic source and association of trace elements with Fe, Mn and Al and of Pb with U. Geoaccumulation index revealed for Ni an extremely contaminated situation at the estuary water during monsoon and for Cd a heavily contaminated situation at freshwater location. The potential contamination index was >6; thus, sediments were very severely contaminated by As, Cd and Ni with worst situation for As and Cd at fresh and brackish water and during post-monsoon. The overall ecological risk was severe, 300≤RI<600 at all sites and seasons, especially after the monsoon, at fluvial and brackish locations.

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52.
Physical shelter features (e.g. shape, size and substrate slope) were tested in the laboratory to evaluate the preferences of juveniles of European spiny lobster, Palinurus elephas. Tethering experiments to assess whether substrate slope affects the vulnerability of juveniles to predation were also performed. Our results showed that: (1) semi-circular dens were significantly preferred over square and circular shapes; (2) when not disturbed by a predator, lobsters sheltered in holes with a diameter closely related to their own size, while in the presence of a potential predator lobsters showed no significant preference for a particular shelter size; (3) lobsters significantly preferred dens excavated on sub-vertical (35°) substrates over those excavated on vertical ones (90°); (4) individual lobsters tethered on vertical substrates were subject to greater predation activity than those tethered on horizontal structures. In conclusion, the present study contributes to the understanding of how physical properties of shelters affect the choice of P. elephas juveniles, enhancing their protection and survival rate.  相似文献   
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54.
Invasive species pose significant ecological costs, and therefore successful management techniques are important. One commonly employed method is biological control. The success of biological control depends largely on whether additional inflicted damage can successfully reduce the fitness and population growth rate of a target species. Here, we simulate herbivory on the invasive Lespedeza cuneata and create stage-structured projection models to determine if augmented herbivory by a leaf-chewing biological control agent would regulate the population growth rate of this species. We found that augmented herbivory influenced stage transitions of plants in the smallest stage class, causing higher mortality and reduced growth. No other effect was found on stage transitions or fecundities, despite manipulation of herbivory at exceptionally high levels (up to 80% leaf loss). None of the clipping treatments significantly reduced the population growth rate of L. cuneata. We conclude that biological control by a leaf chewing herbivore would not likely be successful, even if an exceptionally large amount of each plant were consumed. We suggest that this approach, a combination of simulated herbivory and demographic modeling, will provide essential information for understanding the utility of biological control to curb the population growth of invasive plant species.  相似文献   
55.
We examine how demographic context influences the trust that boundary spanners experience in their dyadic relationships with clients. Because of the salience of age as a demographic characteristic as well as the increasing prevalence of age diversity and intergenerational conflict in the workplace, we focus on team age diversity as a demographic social context that affects trust between boundary spanners and their clients. Using social categorization theory and theories of social capital, we develop and test our contextual argument that a boundary spanner's experience of being trusted is influenced by the social categorization processes that occur in dyadic interactions with a specific client and, simultaneously, by similar social categorization processes that influence the degree to which the client team as a whole serves as a cooperative resource for demographically similar versus dissimilar boundary spanner–client dyads. Using a sample of 168 senior boundary spanners from the consulting industry, we find that generational diversity among client team members from a client organization undermines the perception of being trusted within homogeneous boundary spanner–client dyads while it enhances the perception of being trusted within heterogeneous dyads. The perception of being trusted is an important aspect of cross‐boundary relationships because it influences coordination and the costs associated with coordination. © 2015 The Author Journal of Organizational Behavior Published by John Wiley & Sons Ltd  相似文献   
56.
Small farmers who supply the city of Bogotá with food are facing many challenges that are jeopardizing their livelihoods and by extension, the food security of Colombia’s capital. We expect future changes in climatic conditions to exacerbate the plight of the small farmers and this is expected to compromise Bogota’s food security even further. This paper specifically seeks to assess the impact of climate change (CC) on the livelihoods of smallholders who supply Bogota with most of its food. In our multidisciplinary methodology, we translated the exposure to CC into direct impact on crops and assessed sensitivity and adaptive capacity using the sustainable rural livelihoods framework. The results show that rainfall (by average of 100 mm) and temperature (by average of 2.1 °C) will increase over the study area, while the future climate suitability of the most important crops such as mango (Mangifera indica), papaya (Carica papaya), corn (Zea mays) and plantain (Musa balbisiana) shows a decrease of 19 % to 47 % climate suitability by the year 2050. The assessment of sensitivity and adaptive capacity demonstrates that farmers participating in a farmers’ market, initiated by several local and international non-governmental organizations (NGOs), are less vulnerable to CC than farmers who sell through intermediaries. Those farmers selling directly to consumers in the farmers’ market have a higher adaptive capacity (3 on a scale of 3) in social and financial capital than those selling to intermediaries with less adaptive capacity (1 on a scale of 3). In light of the reduction in overall climatic suitability of some of the major crops and the change of geographic location of suitability for others, there are likely to be serious threats for Bogotá’s food security, the ecological landscape around the city, and farmers’ livelihoods. We further conclude that unless proper adaptation measures are implemented, the geographical shift in climate suitability may also force farmers to shift their crops to higher elevations including remaining forests and páramos (the Colombian alpine tundra ecosystems), which may be threatened in the near future.  相似文献   
57.
Voluntary GHG management is a primary issue for many organizations. To support organizations with this activity, authoritative bodies have published many different guidelines. Nevertheless, these guidelines show limitations in identification of the direct and indirect processes that have a major impact on climate change, which should be considered in GHG management.In this paper, a life cycle approach is used to identify the processes of an organization and its supply chain that have major impacts on climate change. The results show that this approach is compatible with the current ISO standards and that in the case study the greatest emissions come from the organization’s indirect processes.  相似文献   
58.
Italy is a country highly vulnerable to floods and landslides. The present study aims to investigate disaster preparedness and perception of flood risk in a group of people living in an alpine valley in the north of Italy. Four hundred seven adult residents in nine communities exposed to hydrogeological risk were interviewed by using a structured questionnaire. Participants were asked about the adoption of a set of protective behaviors that can prevent negative consequences of floods. Perception of flood risk was assessed by means of a one-dimensional scale that was developed and validated by the authors. Items included in this scale asked participants to estimate likelihood of occurrence of different flood consequences and to express feelings of worry associated to them. Socio-demographic and experiential information on respondents were also collected. Overall, results showed that most of respondents were fairly well prepared to deal with a future flood disaster. Correlational and regression analyses indicated that disaster preparedness was positively associated with risk perception. In accordance with literature, there was not a significant relation between likelihood judgments and adoption of protective behaviors, while feelings of worry were associated with disaster preparedness. Authors interpret their results in relation to the socio-environmental characteristics of the studied communities. Theoretical, empirical and practical implications of the findings are also discussed.  相似文献   
59.
A bench-scale pilot plant has been developed for the treatment of olive-mill water. The plant is fed in a continuous mode and implements a primary treatment (sand filtering and irradiation with UV-rays) and a secondary treatment (anoxic and aerobic biological treatment). Satisfactory results were obtained and the treated green water falls under the limits of the Italian legislation. Veratric and ferulic acid biodegradation were studied under anoxic conditions in order to verify the requirements for optimal biodegradation. Electronic Publication  相似文献   
60.
ABSTRACT: Californian annual grassland on sandstone (moderately fertile) and serpentine (very infertile) soils at the Jasper Ridge Biological Preserve, Stanford, California, were exposed to ambient or elevated (ambient + 36 Pa CO2) atmospheric CO2 in open-top chambers since December 1991. We measured ecosystem evapotranspiration with open gas-exchange systems, and soil moisture with time-domain reflectometry (TDR) over 0–15 cm (serpentine) and 0–30 cm (sandstone) depths, at times of peak above ground physiological activity. Evapotranspiration decreased by 12 to 63 percent under elevated CO2 in three consecutive years in the sandstone ecosystem (p = 0.053, p = 0.162, p = 0.082 in 1992, 1993, and 1994, respectively). In correspondence with decreased evapotranspiration, late-season soil moisture reserves in the sandstone were extended temporally by 10 ± 3 days in 1993 and by 28 ± 11 days in 1994. The effect of elevated CO2 on soil moisture was greater in the drier spring of 1994 (419 mm annual rainfall) than in 1993 (905 mm annual rainfall). In the serpentine ecosystem, evapotranspiration and soil moisture reserves were not clearly affected by elevated CO2. Soil water may be conserved in drought-affected ecosystems exposed to elevated CO2, but the amount of conservation appears to depend on the relative importance of transpiration and soil evaporation in controlling water flux.  相似文献   
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