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211.
The main purpose of this paper is to use data envelopment analysis (DEA) as a support tool to establish a relative eco-efficiency measure for the different bioethanol transportation modes and to prioritize these different modes according to these figures. From a review of previous studies, we selected a set of attributes to be considered in DEA, and then experts were consulted about the importance of these attributes for this type of analysis in Brazil. To quantify the attributes, we established indicators and submitted them to DEA to evaluate the relative eco-efficiency to each available transportation mode for the case studied. The use of DEA established the guidelines to improve the transportation modes that were not considered 100?% relatively eco-efficient. These improvements could be achieved considering the percentage, reduction or growth for each of the attributes in the selected transportation mode. The proposed approach can help the Brazilian government to develop a plan to improve the bioethanol transportation infrastructure and can be used to propel short-term improvements in the highway transport of bioethanol, which could be useful given the Brazilian transportation context.  相似文献   
212.
The environmental impact caused by the disposal of plastics has motivated the development of biodegradable materials. Recent studies showed that supplementation with oleic acid (OA) in cultures producing poly(3-hydroxybutyrate), P(3HB), increased the polymer productivity. However only few studies have shown the properties and biodegradation profile of the polymer obtained. This research investigated the influence of OA concentration on the biodegradation of the P(3HB) obtained from cultures of Cupriavidus necator. The crystallinity of the casting films determined by differential scanning calorimetry (DSC) was reduced from 70% (0 g L−1 of OA) to 52% (3.0 g L−1 of OA). A reduction of 11 °C in the melting temperature was observed with 3.0 g L−1 of OA. The kinetic of biodegradation was: 3.0 > 1.5 > 0.9 > 0.3 > 0 g L−1 of OA.  相似文献   
213.
Iron (Fe) and other trace elements such as Zn, Mn, Ni and Cu are known as key-factors in marine biogeochemical cycles. It is believed that ocean primary productivity blooms in iron deficient regions can be triggered by iron in aeolian dust. Up to now, scarce aerosol elemental composition, based on measurements over sea at the Western South Atlantic (WSA), exist. An association between the Patagonian semi-desert dust/Fe and chlorophyll-a variability at the Argentinean continental shelf is essentially inferred from models. We present here experimental data of Fe enriched aerosols over the WSA between latitudes 22°S–62°S, during 4 oceanographic campaigns between 2002 and 2005. These data allowed inferring the atmospheric Fe flux onto different latitudinal bands which varied from 30.4 to 1688 nmolFe m?2 day?1 (October 29th–November 15th, 2003); 5.83–1586 nmolFe m?2 day?1 (February 15th–March 6th, 2004) and 4.73–586 nmolFe m?2 day?1(October 21st–November 5th, 2005).  相似文献   
214.
According to indicator models of sexual selection, females can benefit from choosing males with above average epigamic traits, but empirical evidence for such benefits is scarce. Here, we report results from an experiment with 29 pairs of house sparrows (Passer domesticus) where the intensity of nest defense against a mounted mustelid predator was related to the size of the black throat and breast patch (“badge”) in males. Using principal components analysis (PCA), original response variables of both sexes were reduced to two factors: “Approach” to the predator and “Distant warning”. “Approach”, the more risky behavior, increased from small- through medium- to large-badged males and decreased in their females. Since large-badged males have a higher certainty of paternity (i.e. greater benefits from defense) and may be older and more experienced (i.e. incur lower costs), the most likely explanation for male defense intensity increasing with badge size is an improving benefit/cost ratio. The resulting optimal response of their females and evolutionarily stable participation in joint parental care is illustrated by a graphical model. It shows that females would, indeed, benefit directly from choosing large-badged males. This, however, is no proof of a direct evolutionary tie between badge size and paternal behavior, as assumed by indicator models of sexual selection. It may simply represent a spurious relationship, originating from the correlation of badge size and defense with confidence of paternity. Received: 22 September 1997 / Accepted after revision: 3 November 1997  相似文献   
215.
Microbial contamination of fresh produce can present a severe risk to public health. By conducting a rigorous survey of irrigation waters, the impacts of fecal contamination on the quality of produce could be assessed. In this study, surface waters were observed to be contaminated with Escherichia coli, Salmonella spp., and somatic coliphages. Culture methods show that out of 373 irrigation water, soil, and vegetable samples collected for a 1-year period, 232 (62.20%) were found positive for E. coli, 213 (57.26%) for somatic coliphages, and 2 (0.53%) for Salmonella spp. Out of 190 water samples, 167 (87.9%) were found to have E.coli, 174 (91.6%) have somatic coliphages, and 1 (0.5%) with Salmonella spp. In soil samples, 36 of 91 (39.6%) have E. coli, 31 (34.0%) have somatic coliphages, and none with Salmonella spp. Lastly, out of 92 vegetable samples, 29 (31.5%), 8 (8.7%), and 1 (1.1%) were found to have E. coli, somatic coliphages, and Salmonella spp., respectively. Molecular analysis confirmed the presence of bacterial contaminants. Seasonal weather conditions were noted to have an effect on the presence and number of these fecal indicator organisms. The observed data suggest that contaminated irrigation water may greatly affect the quality of fresh produce from these agricultural operations.  相似文献   
216.
We maintained a factorial nitrogen (N), phosphorus (P), and potassium (K) addition experiment for 11 years in a humid lowland forest growing on a relatively fertile soil in Panama to evaluate potential nutrient limitation of tree growth rates, fine-litter production, and fine-root biomass. We replicated the eight factorial treatments four times using 32 plots of 40 x 40 m each. The addition of K was associated with significant decreases in stand-level fine-root biomass and, in a companion study of seedlings, decreases in allocation to roots and increases in height growth rates. The addition of K and N together was associated with significant increases in growth rates of saplings and poles (1-10 cm in diameter at breast height) and a further marginally significant decrease in stand-level fine-root biomass. The addition of P was associated with a marginally significant (P = 0.058) increase in fine-litter production that was consistent across all litter fractions. Our experiment provides evidence that N, P, and K all limit forest plants growing on a relatively fertile soil in the lowland tropics, with the strongest evidence for limitation by K among seedlings, saplings, and poles.  相似文献   
217.
Gardening has become a relevant contributor to the quality of life of suburbanites, as a source of leisure, to build a relationship with nature or to express a particular social identity. Nevertheless, water scarcity in the Mediterranean region has increased concerns about how demand should be managed to face future uncertainties, and watering the gardens has become an element for discussion in urban planning. This contribution presents the findings of a survey of permanent residents and secondary homeowners (n?=?230) in the suburban areas surrounding the city of Girona in the northeast of Catalonia (Spain). The area is a popular national and international tourist destination and a preferred place for second-home owners. We explore the main socio-demographic drivers for choosing an alternative watering source and we analyse if water-harvesting tank sizes properly meet net irrigation requirements. Results show that many water-harvesting tanks are oversized. The percentage of unemployed or retired household members, the estimated irrigation water needs of the garden and the education level directly influence the search for alternative sources of water. Moreover, social variables like interest in gardening, water conservation attitudes and household income indirectly influence the search for alternative sources of water.  相似文献   
218.
219.
Nano zerovalent iron (nZVI) is a promising remediation technology utilizing in situ chemical reduction (ISCR) to clean up contaminated groundwater at hazardous waste sites. The small particle size and large surface area of nZVI result in high reactivity and rapid destruction of contaminants. Over the past 20 years, a great deal of research has advanced the nZVI technology from bench‐scale tests to field‐scale applications. However, to date, the overall number of well‐characterized nZVI field deployments is still small compared to other alternative remedies that are more widely applied. Apart from the relatively high material cost of nZVI and questions regarding possible nanotoxicological side effects, one of the major obstacles to the widespread utilization of nZVI in the field is its short persistence in the environment due to natural reductant demand (NRD). The NRD for nZVI is predominantly due to reduction of water, but other reactions with naturally present oxidants (e.g., oxygen) occur, resulting in situ conditions that are reducing (high in ferrous iron phases and H2) but with little or no Fe(0). This article reviews the main biogeochemical processes that determine the selectivity and longevity of nZVI, summarizes data from prior (laboratory and field) studies on the longevity of various common types of nZVI, and describes modifications of nZVI that could improve its selectivity and longevity for full‐scale applications of ISCR. © 2016 Wiley Periodicals, Inc.  相似文献   
220.
This study evaluated the influence of the clomazone herbicide (2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone) contamination on the hematological parameters and histological changes in gills and liver of silver catfish (Rhamdia quelen) from Madre River, Santa Catarina State, Southern Brazil. Fish were collected between March 2010 and January 2012 at two different sites of the Madre River, one site receiving residual water (contaminated site) from rice culture (n = 49) and another that do not receive residual water (reference site) (n = 48). The herbicide clomazone analysis detected 3.40 ± 1.70 μg/L in the contaminated site and 1.1 ± 0.33 μg/L in the reference site. Fish from contaminated site showed increased (P < 0.05) number of monocytes suggesting the possible defense response as a result of chronic exposure to clomazone. On the other hand, no difference was found in the hematocrit percentage, red blood cell count, total thrombocyte number, white blood cell count, lymphocytes, and neutrophils number. Fish from both sites showed histopathological changes in gills and liver, possibly caused by chronic exposure to contamination. The influence of herbicide sub doses on fish health is also discussed.  相似文献   
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