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391.
Marco A.González 《生态毒理学报》2003,25(1):32-36
资金匮乏仍然是阻碍企业广泛实施清洁生产的主要原因之一.这一问题在中小企业中尤为严重,因为资金提供方往往认为投资它们比投资大企业的风险大,而收益却很小.这种状况非常不利于拉丁美洲实现清洁生产,因为中小企业在拉丁美洲工业部门中占的比例非常之大(约为 95%).联合国环境署( UNEP)赞助的拉丁美洲清洁生产信贷计划将利用清洁生产中心的经验和技术、国际绿色基金以及财力雄厚的地方商业银行帮助该地区实现清洁生产. 相似文献
392.
Nadia Scascighini Letizia Mattiacci Marco D’Alessandro Alan Hern Anja Sybille Rott Silvia Dorn 《Chemoecology》2005,15(2):97-104
Summary. It is well known that feeding by Pieris brassicae caterpillars on cabbage leaves triggers the release of volatiles that attract natural antagonists such as the parasitoid Cotesia glomerata. The temporal dynamics in the emissions of parasitoid attracting volatiles has never been elucidated in this system. In a time course experiment, caterpillar infested leaves attracted the parasitoid within one hour after infestation. At such an early stage of infestation, as much as fifty percent of the parasitoids flew towards the infested plant in a wind tunnel bioassay, while only five percent flew towards the non-infested control plant. Three hours after infestation and later, the response to the volatiles from the infested plant reached its maximum and then continued at a constantly high level for the remaining 14 hours of the experiment. Chemical analyses of volatiles collected from infested leaves at short time intervals during the first 24 hours identified a total of ten compounds, comprising green leaf volatiles, terpenoids, and a nitrile. Significant increase of emission within the first 5 hours following initial herbivory was detected for (Z)-3-hexen-1-ol, (Z)-3-hexen-1-yl acetate, cineole and benzylcyanide. Subsequently, a coupled bioassay-chemical analysis procedure was developed allowing for testing and analyzing the same sample for future identification of the bioactive compounds. This was achieved by using stir bar sorptive extraction for the analysis of solvent extracts of caterpillar-damaged leaves. 相似文献
393.
Jean-François Therrien Steeve D. Côté Marco Festa-Bianchet Jean-Pierre Ouellet 《Behavioral ecology and sociobiology》2007,62(2):193-199
When resources are limited, life history theory predicts a trade-off between growth, reproduction and survival. In summer,
lactating females of temperate large herbivores such as the white-tailed deer (Odocoileus virginianus) normally have access to abundant forage but also face the high energetic needs of lactation and recovery from winter mass
loss. At high population density, however, females may face a trade-off between allocating resources for maintenance and for
reproduction. To simulate the effects of increased intra-specific competition at high density, we measured for 2 years how
an experimental food restriction of approximately 20% affected current reproduction and body mass changes of adult females
and their fawns during the fawning and lactation periods. Fawn survival decreased 35%, and fawn growth decreased 26% in the
food-restricted treatment. There was no effect of food restriction on female mass. Irrespective of treatment, however, lactating
females gained 30 g/day less than non-lactating females, and females that had weaned a fawn the previous year gained 20 g/day
less than females that had not. We conclude that when resources were scarce, females adopted a conservative strategy favouring
their own survival, mass recovery and future reproductive potential over their current reproduction, probably to maximise
their lifetime reproductive success. 相似文献
394.
Geographic Analysis of California Condor Sighting Data 总被引:3,自引:0,他引:3
David M. Stoms Frank W. Davis Christopher B. Cogan Marco O. Painho Brean W. Duncan Joseph Scepan J. Michael Scott 《Conservation biology》1993,7(1):148-159
Observation and habitat data were compiled and analyzed in conjunction with recovery planning for the endangered California Condor ( Gymnogyps californianus ). A geographic information system (GIS) was used to provide a quantitative inventory of recent historical Condor habitats, to measure the association of Condor activity patterns and mapped habitat variables, and to examine spatio-temporal changes in the range of the species during its decline. Only five percent of the study area within the historic range is now used for urban or cultivated agricultural purposes. Observations of Condor feeding perching, and nesting were nonrandomly associated with mapped land cover, in agreement with life history information for the species. The precipitous decline in numbers of Condors in this century produced only a small reduction in the limits of the observed species' range, as individual birds continued to forage over most of the range. Some critical risk factors such as shooting and lead poisoning are difficult to map and have not been included in the database. Besides the applications demonstrated in this case study, GIS can be a valuable tool for recovery planning, in the design of stratified sampling schemes, or for extrapolation of habitat models over unsurveyed regions. We conclude with recommendations from this case study regarding when to consider using GIS and the importance of pilot studies and sensitivity analysis. 相似文献
395.
The genetic relationships between morphologically indistinguishable marine and brackish-water populations of Monocelis lineata (O.F. Müller, 1774) (Proseriata: Monocelididae) were analysed by means of allozyme electrophoresis. Fifteen samples of M. lineata (13 from the Mediterranean and two from the Atlantic) from coastal marine and brackish-water habitats were examined for variation at 18 loci. Eleven loci were polymorphic in at least one population of M. lineata. Low levels of within-population genetic variability were found, with average observed and expected heterozygosity values ranging from Ho=0.015±0.015 to 0.113±0.044, and from
He=0.028±0.028 to 0.138±0.054, respectively. The occurrence of a number of private alleles indicated a marked genetic divergence among populations of M. lineata, with Rogers genetic distances ranging from
DR=0.003 to 0.676 and a highly significant FST value (0.918±0.012, P<0.001). UPGMA (unweighted pair-group method using arithmetic average) cluster analysis and multidimensional scaling showed a clear genetic divergence between marine and brackish-water populations. Moreover, Atlantic and Mediterranean populations were sharply separated. Our results suggest that M. lineata is a complex of sibling species.Communicated by R. Cattaneo-Vietti, Genova 相似文献
396.
Azo-dyes photocatalytic degradation in aqueous suspension of TiO2 under solar irradiation 总被引:3,自引:0,他引:3
Augugliaro V Baiocchi C Prevot AB García-López E Loddo V Malato S Marcí G Palmisano L Pazzi M Pramauro E 《Chemosphere》2002,49(10):1223-1230
The photodegradation of two common and very stable azo-dyes, i.e. methyl-orange (C14H14N3SO3Na) and orange II (C16H11N2SO4Na), is reported. The photocatalytic oxidation was carried out in aqueous suspensions of polycrystalline TiO2 irradiated by sunlight. Compound parabolic collectors, installed at the “Plataforma Solar de Almería” (PSA, Spain) were used as the photoreactors and two identical reacting systems allowed to perform photoreactivity runs for the two dyes at the same time and under the same irradiation conditions. The disappearance of colour and substrates together with the abatement of total organic carbon content was monitored. The main sulfonate-containing intermediates were found to be in lower number in respect to those obtained under artificial irradiation. In particular there were no more evidence of the presence of hydroxylated transients. The dependence of dye photooxidation rate on: (i) substrate concentration; (ii) catalyst amount; and (iii) initial pH was investigated. The influence of the presence of strong oxidant species (H2O2, S2O82−) and some ions (Cl−, SO42−) on the process was also studied. 相似文献
397.
Bussotti F Gerosa G Cenni E Cozzi A Ferretti M Bettini D Nibbi R 《Environmental monitoring and assessment》2003,85(3):221-238
This study examines defoliation and discoloration findings collected throughout the Italian Level I network between 1997 and 2000. Prior to this period no Quality Assurance procedures had been implemented, so that earlier findings cannot be considered reliable. The aim of the study is to compare differentindices used in reporting findings, in order to determine the full potential and limitations of each. In international surveys,findings are normally expressed in terms of individual trees presenting a defoliation level greater than 2 %; this criterion,however, has been challenged since it is not based on scientificevidence. By analysing the distribution of defoliation values(grouped in 5% classes) relating to the main species (Fagus sylvatica, Quercus pubescens, Quercus cerris, Picea abies), the study examines the behaviour of statistical indices such as the median, the mode and the mean. Instead of using the traditional 25% threshold to determine the part of the population with the highest defoliation values, a procedureis suggested whereby a different threshold can be determined foreach species. It is established based on the 90° percentile of cumulative defoliation values recorded over the four-year period. Each index used to report findings possessesits own information potential, and the findings may at times appear contradictory. The use of a combined defoliation and discoloration index (Ilce = Lacking Crown Equivalent Index) is also proposed, but the results obtained do not differin substance from the results relating to defoliation alone. Thefunctional limitations of this index are due mainly to the way the data are collected: for this reason suggestions are made onhow to improve the procedure in future surveys. 相似文献
398.
Nadine Salzmann Stephan Gruber Marco Hugentobler Martin Hoelzle 《Environmental Modeling and Assessment》2007,12(4):303-313
The thawing of alpine permafrost due to changes in atmospheric conditions can have a severe impact, e.g., on the stability
of rock walls. The energy balance model, PERMEBAL, was developed in order to simulate the changes and distribution of ground
surface temperature (GST) in complex high-mountain topography. In such environments, the occurrence of permafrost depends
greatly on the topography, and thus, the digital terrain model (DTM) is an important input of PERMEBAL. This study investigates
the influence of the DTM on the modeling of the GST. For this purpose, PERMEBAL was run with six different DTMs. Five of the
six DTMs are based on the same base data, but were generated using different interpolators. To ensure that only the topographic
effect on the GST is calculated, the snow module was turned off and uniform conditions were assumed for the whole test area.
The analyses showed that the majority of the deviations between the different model outputs related to a reference DTM had
only small differences of up to 1 K, and only a few pixels deviated more than 1 K. However, we also observed that the use
of different interpolators for the generation of a DTM can result in large deviations of the model output. These deviations
were mainly found at topographically complex locations such as ridges and foot of slopes. 相似文献
399.
Calace N Cantafora E Mirante S Petronio BM Pietroletti M 《Journal of environmental monitoring : JEM》2005,7(12):1320-1325
We performed a study of fulvic acids extracted from fresh and aged snow, and from recent and ancient ice in Antarctica. The fresh snow samples were collected in coastal and inland sites to evaluate the influence of the distance from the sea on organic matter transport. Moreover, in a site (Melbourne Mountain) samples were collected at different heights to study the influence of altitude on transport. The obtained results showed that dissolved fulvic acid concentrations are influenced neither by distance nor by height while particulate fulvic acid concentrations are influenced by both parameters. Moreover, the results showed that fulvic acids transported for a long distance can undergo chemical modifications. Chemical modifications are better evidenced by the analysis of samples taken in trenches at different depth, which showed structural changes attributable to the loss of nitrogen-containing compounds and to an increase in aromatic character of the structures due to reduction and/or condensation processes. With ageing, the humification process proceeds with heavy carbon losses as demonstrated by results obtained from fulvic acids isolated from ice aged between twenty-five thousand and seventy thousand years. 相似文献
400.
Silvia Canepari Enrico Cardarelli Cinzia Perrino Maria Catrambone Adriana Pietrodangelo Marco Strincone 《Atmospheric environment (Oxford, England : 1994)》2006,40(40):7908-7923
A two-stage micro-analytical scheme for the determination of metals and ions in atmospheric particulate matter collected on only one Teflon filter was developed. In the first stage the collected particles are chemically fractionated for their solubility in a pH-buffered extracting solution; in the second stage the residue is mineralised. The major non-volatile inorganic ions (Cl−, NO3−, SO42−, Na+, NH4+, Ca2+, Mg2+) are determined in the first fraction by ion-chromatography (IC), while metals and metalloids (Al, As, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, S, Sb, Se, Si, Ti, V, Zn) are determined in both the acetate extractable and the mineralised residual fractions by inductively coupled plasma optical emission spectroscopy (ICP-OES).The procedure was applied to ambient 24-h PM10 samples collected on Teflon filters during two field campaigns carried out at two sites in the area of Rome (Italy). The variations in the chemical composition of the collected particles during the two periods were interpreted in the light of the dilution properties of the lower atmosphere and of the back-trajectories of the air masses. The difference in the results between the two locations was interpreted in the light of their proximity to the emission sources. It was found that the acetate extractable and the mineralised residual fraction of some metals exhibit a different temporal pattern, suggesting the existence of different emission sources of the two fractions. 相似文献