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461.
Green public procurement (GPP) promises great potential for improving the environmental impact of many public organizations. However, the effects this instrument will have in the near future are unclear as there is little evidence on its exact level of engagement. This study thus aims to analyze the contents of tenders in terms of green criteria by specifically focusing on the building and construction sector. A total of 164 Italian public tenders were analyzed according to a protocol of analysis based on the GPP toolkit developed by the European Commission. Starting from a content analysis used in previous studies, a complete list of green criteria was developed in order to investigate their prevalence in the sample selected, with the aim of exploring their frequency, distribution and correlation. The results revealed a limited use of green criteria, which were mainly included as technical specifications and award criteria, thus shedding light on the difficulties that procurers are experiencing in the implementation of GPP practices. Several suggestions for policy makers and managers are identified for a better and faster implementation of green public procurement tools and methods.  相似文献   
462.
Abstract

This study evaluates air quality model sensitivity to input and to model components. Simulations are performed using the California Institute of Technology (CIT) airshed model. Results show the impacts on ozone (O3) concentration in the South Coast Air Basin (SCAB) of California because of changes in: (1) input data, including meteorological conditions (temperature, UV radiation, mixing height, and wind speed), boundary conditions, and initial conditions (ICs); and (2) model components, including advection solver and chemical mechanism. O3 concentrations are strongly affected by meteorological conditions and, in particular, by temperature. ICs also affect O3 concentrations, especially in the first 2 days of simulation. On the other hand, boundary conditions do not significantly affect the absolute peak O3 concentration, although they do affect concentrations near the inflow boundaries. Moreover, predicted O3 concentrations are impacted considerably by the chemical mechanism. In addition, dispersion of pollutants is affected by the advection routine used to calculate its transport. Comparison among CIT, California Photochemical Grid Model (CALGRID), and Urban Airshed Model air quality models suggests that differences in O3 predictions are mainly caused by the different chemical mechanisms used. Additionally, advection solvers contribute to the differences observed among model predictions. Uncertainty in predicted peak O3 concentration suggests that air quality evaluation should not be based solely on this single value but also on trends predicted by air quality models using a number of chemical mechanisms and with an advection solver that is mass conservative.  相似文献   
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Sediment samples from 25 sites in 17 rivers of the Pantanal (Brazil) were analyzed with the objective of evaluating pesticide contamination in sediments. Samples were extracted with an acetone, ethylacetate, and water mixture 2:2:1 (v/v/v). The extract was purified by flash chromatography with aluminum oxide and florisil. A multiresidue gas chromatography-mass spectrometry method was applied to monitor 23 pesticides of different chemical classes (organochlorine, organophosphorus, triazines, anilides and pyrethroids) with some of their degradation products. Compounds identified in sediment samples included λ -cyhalothrin (1.0 to 5.0 μ g kg? 1), p,p′-DDT (3.6 μ g kg? 1), deltamethrin (20.0 μ g kg? 1) and permethrin (1.0 to 7.0 μ g kg? 1).  相似文献   
467.
A new method for the recovery of precious metals, in particular gold, from electronic waste is proposed. This work focused on the research of an easily renewable etching agent, in order to make an environmentally friendly process possible. Two well known hydrometallurgical etching agents, FeCl3 and CuCl2, were evaluated in terms of efficiency and kinetics, testing solutions with different concentration of etchant and hydrochloric acid. The recovery of spent etching solutions was evaluated: promising results were found in the case of CuCl2, which can be completely restored by oxidation of the cuprous chloride formed during the etching using atmospheric oxygen.  相似文献   
468.
Although functional explanations for female engagement in extra-pair copulation have been studied extensively in birds, little is known about how extra-pair paternity is linked to other fundamental aspects of avian reproduction. However, recent studies indicate that the occurrence of extra-pair offspring may generally decline with laying order, possibly because stimulation by eggs induces incubation, which may suppress female motivation to acquire extra-pair paternity. Here we tested whether experimental inhibition of incubation during the laying phase, induced by the temporary removal of eggs, resulted in increased extra-pair paternity, in concert with a later cessation of laying, in blue tits (Cyanistes caeruleus). As expected, experimental females showed a more gradual increase in nocturnal incubation duration over the laying phase and produced larger clutches than controls. Moreover, incubation duration on the night after the first egg was laid predicted how extra-pair paternity declined with laying order, with less incubation being associated with more extra-pair offspring among the earliest eggs in the clutch. However, incubation duration on this first night was unrelated to our experimental treatment and independent of final clutch size. Consequently, the observed decline in extra-pair paternity with laying order was unaffected by our manipulation and larger clutches included proportionally fewer extra-pair offspring. We suggest that female physiological state prior to laying, associated with incubation at the onset of laying, determines motivation to acquire extra-pair paternity independent of final clutch size. This decline in proportion of extra-pair offspring with clutch size may be a general pattern within bird species.  相似文献   
469.
Environmental Science and Pollution Research - The installation of district heating (DH) systems constitutes an advantage from the energetic, climate, and air quality aspects. However, the...  相似文献   
470.
This paper focused on the past shoreline change rates along the coastal plain of the Volturno River, in southern Italy, western Mediterranean. A wide database comprising historical maps, aerial photographs, topographic sheets, bathymetric data was used to extract the spatial and temporal information of the coastlines at seven time points. Coastline displacement was calculated for two successive time points and relative surface variation (accretion and erosion) was estimated as well as minimum and maximum accretion/erosion linear values and rates. The surface variation analysis has revealed that the studied coast can be considered homogeneous since the 1970s, whereas it exhibits a variety of shoreline evolutionary trends after that time period. Timing and causes of trends and rates of variation were detected. Based on the estimated shoreline change rates, an appropriate morhodynamic one-line model was applied to predict evolutionary scenarios also in presence of port and defence works. The results obtained strongly emphasize that a successful coastal management requires a constant monitoring of the human-induced changes to account for the variability of rates over time.  相似文献   
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