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801.
Bernardo Guimarães Pedro Simões Rui Cunha Marques 《Journal of environmental management》2010,91(12):2632-2638
The urban waste market has evolved significantly in the past decades, which among other changes, has led to the creation of new utilities and new business models. However, very few things have changed for the users. Urban waste collection remains mainly under the responsibility of local authorities and the charges paid by the users in most countries are very low compared to the provision costs. This situation forces the injection of public money into the system, encouraging the ‘quiet-life’ within the utilities and, therefore, inefficiency. The present study intends to analyze the potential for the application of the Balanced Scorecard (BSc) methodology into the waste utilities. After a comprehensive revision of the urban waste sector in Portugal, the methodology of BSc and its application in local public services is described and discussed. Focusing on implementation rather than on strategy, a set of performance indicators is proposed to be utilized in the different management models of waste utilities in Portugal: the municipalities, semi-autonomous utilities, municipal companies and mixed companies. This implementation is then exemplified through four case studies, one for each type of utility. This paper provides a flexible framework proposal to be applied to waste utilities operating both in Portugal and abroad. 相似文献
802.
803.
D. F. Parra D. S. Rosa J. Rezende P. Ponce A. B. Lugão 《Journal of Polymers and the Environment》2011,19(4):918-925
Poly(3-hydroxybutyrate) (PHB) was evaluated in blends with poly(ethyleneglycol) (PEG) of different weight average molecular
weight (Mw = 300, 600, 1,000 and 6,000). Irradiation of the PHB/PEG films was carried out to different levels of irradiation
doses (5 and 10 kGy) and the effects were investigated talking into consideration: thermal properties by differential scanning
calorimetry (DSC), perforation resistance, water vapor transmission rate and biodegradation in simulated soil. The addition
of plasticizer alters thermal stability and crystallinity of the blends. The improvement in perforation resistance due to
irradiation was regarded to be a result of the crosslinking effect. Also, biodegradation assays resulted in mass retention
improvements with increases in PEG molar masses, PEG concentration and irradiation dose. The irradiation process was shown
to hamper the biodegradation mechanism. 相似文献
804.
Marcela M.C. Campos Vanessa H.F. Faria Taciane S. Teodoro Francisco A.R. Barbosa Sérgia M.S. Magalhães 《Journal of environmental science and health. Part. B》2013,48(2):101-107
The bioaccumulation of atrazine and its toxicity were evaluated for the cyanobacterium Microcystis novacekii. Cyanobacterial cultures were grown in WC culture medium with atrazine at 50, 250 and 500 μg L?1. After 96 hours of exposure, 27.2% of the atrazine had been removed from the culture supernatant. Spontaneous degradation was found to be insignificant (< 9% at 500 μg L?1), indicating a high efficiency for the bioaccumulation of atrazine by M. novacekii. There were no atrazine metabolites detected in the culture medium at any of the doses studied. The acute toxicity (EC50) of atrazine to the cyanobacterium was 4.2 mg L?1 at 96 hours demonstrating the potential for M. novacekii to tolerate high concentrations of this herbicide in fresh water environments. The ability of M. novacekii to remove atrazine combined with its tolerance of the pesticide toxicity showed in this study makes it a potential biological resource for the restoration of contaminated surface waters. These findings support continued studies of the role of M. novacekii in the bioremediation of fresh water environments polluted by atrazine. 相似文献
805.
Joël Meunier Susana Figueiredo Pinto Reto Burri Alexandre Roulin 《Behavioral ecology and sociobiology》2011,65(4):559-567
Although melanin is the most common pigment in animal integuments, the adaptive function of variation in melanin-based coloration
remains poorly understood. The individual fitness returns associated with melanin pigments can be variable across species
as these pigments can have physical and biological protective properties and genes involved in melanogenesis may vary in the
intensity of pleiotropic effects. Moreover, dark and pale coloration can also enhance camouflage in alternative habitats and
melanin-based coloration can be involved in social interactions. We investigated whether darker or paler individuals achieve
a higher fitness in birds, a taxon wherein associations between melanin-based coloration and fitness parameters have been
studied in a large number of species. A meta-analysis showed that the degree of melanin-based coloration was not significantly
associated with laying date, clutch size, brood size, and survival across 26 species. Similar results were found when restricting
the analyses to non-sexually dimorphic birds, colour polymorphic and monomorphic species, in passerines and non-passerines
and in species for which inter-individual variation in melanism is due to colour intensity. However, eumelanic coloration
was positively associated with clutch and brood size in sexually dimorphic species and those that vary in the size of black
patches, respectively. Given that greater extent of melanin-based coloration was positively associated with reproductive parameters
and survival in some species but negatively in other species, we conclude that in birds the sign and magnitude of selection
exerted on melanin-based coloration is species- or trait-specific. 相似文献
806.
Ana Catarina Ferreira Silva Sónia Brazão Steve J. Hawkins Richard C. Thompson Diana M. Boaventura 《Marine Biology》2009,156(12):2591-2599
Wave action is known to influence the abundance and distribution of intertidal organisms. Wave action will also determine
the duration and suitability of various foraging windows (high-tide and low-tide, day and night) for predation and can also
affect predator behaviour, both directly by impeding prey handling and indirectly by influencing prey abundance. It remains
uncertain whether semi-terrestrial mobile predators such as crabs which can access intertidal prey during emersion when the
effects of wave action are minimal, are influenced by exposure. Here, we assessed the effect of wave action on the abundance
and population structure (size and gender) of the semi-terrestrial intertidal crab Pachygrapsus marmoratus on rocky shores in Portugal. The activity of P. marmoratus with the tidal cycle on sheltered and exposed shores was established using baited pots at high-tide to examine whether there
was activity during intertidal immersion and by low-tide searches. Because prey abundance varies along a wave exposure gradient
on most Portuguese shores and because morphology of crab chelipeds are known to be related to diet composition, we further
tested the hypothesis that predator stomach contents reflected differences in prey abundance along the horizontal gradient
in wave exposure and that this would be correlated with the crab cheliped morphology. Thus, we examined phenotypic variation
in P. marmoratus chelipeds across shores of differing exposure to wave action. P. marmoratus was only active during low-tide. Patterns of abundance and population structure of crabs did not vary with exposure to wave
action. Stomach contents, however, varied significantly between shores of differing exposure with a higher consumption of
hard-shelled prey (mussels) on exposed locations, where this type of prey is more abundant, and a higher consumption of barnacles
on sheltered shores. Multivariate geometric analysis of crab claws showed that claws were significantly larger on exposed
shores. There was a significant correlation between animals with larger claws and the abundance of mussels in their stomach.
Variation in cheliped size may have resulted from differing food availability on sheltered and exposed shores. 相似文献
807.
Pablo del Río Miguel Ángel Tarancón Morán Fernando Callejas Albiñana 《Journal of Cleaner Production》2011,19(11):1170-1179
The aim of this paper is to empirically assess the determinants of environmental technology investments in the Spanish industrial sectors with the help of panel data econometric techniques. The paper confirms the relevance of the stringency of environmental regulation to explain overall investment patterns in environmental technologies. These investments are also positively related to human and physical capital intensity and R&D intensity, and negatively related to the export intensity of sectors. Furthermore, the study shows that the determinants for investments are likely to differ between environmental technology types (i.e., end-of-pipe versus cleaner technologies). 相似文献
808.
The city of Saint-Louis is marked by recurrent floods, despite the decrease in rainfall. The town that grew downstream the vast plain where Senegalese-Mauritanian basin topography flattens considerably has experienced periodic flooding since its foundation. In 2003, the premature flooding of the Senegal River urged the Senegalese authorities to take the initiative to open a breach in the coastal sand strip of the “Langue de Barbarie,” in order to evacuate the water surplus from the river to the ocean and therefore resolve forever the problem of river flooding. But the disruption of estuarine dynamics has led to a rapid expansion of this gap: a few meters wide at its excavation, it reaches over 2,700 m in August 2009. Moreover, 10 months after the widening of the gap, the old river mouth was completely closed. If the natural movement of a mouth can be observed on some major deltas in the world (even on the Senegal River in the past), this is here a true man-made relocation. Based on the statistical analysis of series of hydrological data, this article demonstrates on the one hand that climatic conditions in 2003 which generated a major flood is an anomaly detected in the sequence of dry climate variability observed in the Sahel. On the other hand, it studies the rapid evolution of this new mouth of the Senegal River and discusses some of impacts on the regional social–ecological system, in this sensitive Sahelian environment. 相似文献
809.
810.
Maria João Magalhães Margarida C. De Barros 《Environmental monitoring and assessment》1987,8(1):37-57
In a baseline study, muscle and liver from important commercial fish belonging to different trophic levels were analysed for organochlorines. Samples of sole, sardine and hake were collected from seven locations off the Continental coast and greater forkbeard and horse mackerel off two Azores islands. Residues of ppDDT, ppDDE and PCBs were present in all muscle and liver samples. ppDDD occurred in all liver samples and in most muscle samples, except in sole where it occurred in 29% of the samples. Dieldrin was detected less frequently and did not occur in samples from the Azores. The residue levels were generally similar to those detected in related species from the North Sea, except for samples of sole collected between the Tagus and Sado estuaries where much higher residues were obtained. In view of the low consumption of insecticides in the Azores, it is proposed that long-range transport of organochlorines by winds and/or marine currents is responsible for their presence in this area. The organochlorine residues found in these fish showed no relationship with their position in the food chain but the values did increase with the quantity of lipids present. An unknown compound analysed by GC-MS interfered with DDE quantification in one sample of greater forkbeard. 相似文献