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61.
Faced with a growing demand from the disabled community in Europe and encouraged by new regulations regarding people with disabilities, the French Riviera has joined an initiative which makes its seaside facilities more accessible. Adapted amenities are consequently currently available on the French Riviera. A survey carried out of 20 seaside tourism professionals and representatives of local institutions aimed to understand the underpinning strategies of these developments, which are very heterogeneous as regards their size, their localization, and their level of service. On the whole, it seems that on the French Riviera the services offered to disabled tourists are the product of a mixture of willingness and obligation by the regulations. Disabled people are not yet considered as real clients but as a separate population, not to be mixed with the able-bodied holiday clientele. 相似文献
62.
Jan Peters Niko E.C. Verhoest Roeland Samson Marc Van Meirvenne Liesbet Cockx Bernard De Baets 《Ecological modelling》2009
Ensemble learning techniques are increasingly applied for species and vegetation distribution modelling, often resulting in more accurate predictions. At the same time, uncertainty assessment of distribution models is gaining attention. In this study, Random Forests, an ensemble learning technique, is selected for vegetation distribution modelling based on environmental variables. The impact of two important sources of uncertainty, that is the uncertainty on spatial interpolation of environmental variables and the uncertainty on species clustering into vegetation types, is quantified based on sequential Gaussian simulation and pseudo-randomization tests, respectively. An empirical assessment of the uncertainty propagation to the distribution modelling results indicated a gradual decrease in performance with increasing input uncertainty. The test set error ranged from 30.83% to 52.63% and from 30.83% to 83.62%, when the uncertainty ranges on spatial interpolation and on vegetation clustering, respectively, were fully covered. Shannon’s entropy, which is proposed as a measure for uncertainty of ensemble predictions, revealed a similar increasing trend in prediction uncertainty. The implications of these results in an empirical distribution modelling framework are further discussed with respect to monitoring setup, spatial interpolation and species clustering. 相似文献
63.
Comparative study of the fate and mobility of metals discharged in mining and urban effluents using sequential extractions on suspended solids 总被引:1,自引:0,他引:1
Christian Gagnon Patrice Turcotte Bernard Vigneault 《Environmental geochemistry and health》2009,31(6):657-671
The fate, bioavailability and environmental impacts of metals discharged in municipal and mining wastewater discharge will
depend to a large extent on chemical speciation and distribution. Previous studies on metal bioaccumulation have shown that
total metal concentrations are not a good predictor of bioavailability in the dispersion plumes of municipal effluents. The
objective of this study was to determine the solid phase speciation of metals in surface waters receiving urban and mining
effluents in order to assess their fate and relative mobility in the receiving environment. Suspended particulate matter was
sampled using sediment traps at several sites downstream of effluent outfall plumes as well as at reference upstream sites.
Particulate metal in operationally defined fractions—exchangeable/carbonates, reducible, oxidisable and residual—were determined
in suspended particulate matter with a series of selective chemical extractions. Metal enrichment in suspended particles was
generally observed in both mining and urban effluent discharges. When compared to its receiving environment, the mining effluent
appeared to release more particulate metals (Cu, Fe, Zn) in the most reactive fractions (i.e. exchangeable/carbonates + reducible
forms, 23–43%), while other released metals, such as Cd and Mn, were predominantly in the least reactive forms (i.e., oxidisable + residual,
73–97%). In contrast, the reactivity of all particulate metals, with the exception of Mn, from the urban effluent was much
higher, with up to 65, 42, 30 and 43% for Cd, Cu, Fe and Zn, respectively, in the two most reactive fractions. As expected
in effluent dispersion plumes, parameters such as the organic carbon, Fe oxide and carbonate contents have specific effects
on the partitioning of several trace metals, particularly Cd, Cu and Zn. Our results indicated that the relative distributions
of metals among geochemical fractions varied in the effluent receiving waters where organic carbon and Fe oxides appeared
as the most important parameters. This could therefore decrease the exposure for aquatic organisms that are exposed to those
contaminated sediments as well as the risk to human health. 相似文献
64.
Université de Perpignan 《生态毒理学报》1999,21(4):45-54
珊瑚礁在全世界,尤其两个热带区域和三大洋中都有发育.它们在海水温度高于20℃的沿岸表面附近扩展.它们占据约100万平方公里,是世界上最重要的、由活生物建造的建筑物.珊瑚(约800种)是这些巨大的碳酸钙物体的主要建造者.活珊瑚就落在数以亿万计的祖先骨骼之上.珊瑚之所以有这样一种碳酸钙骨骼的能力,是由于它们与它们在其软组织上繁殖的藻类的共生关系.一平方米的一个珊瑚群落每年能钙化多达10kg碳酸盐.在印度-太平洋地区,石灰藻作为建造者也是重要的. 相似文献
65.
Assessment of spatial distribution of fallout radionuclides through geostatistics concept 总被引:1,自引:0,他引:1
After introducing geostatistics concept and its utility in environmental science and especially in Fallout Radionuclide (FRN) spatialisation, a case study for cesium-137 ((137)Cs) redistribution at the field scale using geostatistics is presented. On a Canadian agricultural field, geostatistics coupled with a Geographic Information System (GIS) was used to test three different techniques of interpolation [Ordinary Kriging (OK), Inverse Distance Weighting power one (IDW1) and two (IDW2)] to create a (137)Cs map and to establish a radioisotope budget. Following the optimization of variographic parameters, an experimental semivariogram was developed to determine the spatial dependence of (137)Cs. It was adjusted to a spherical isotropic model with a range of 30 m and a very small nugget effect. This (137)Cs semivariogram showed a good autocorrelation (R(2)=0.91) and was well structured ('nugget-to-sill' ratio of 4%). It also revealed that the sampling strategy was adequate to reveal the spatial correlation of (137)Cs. The spatial redistribution of (137)Cs was estimated by Ordinary Kriging and IDW to produce contour maps. A radioisotope budget was established for the 2.16 ha agricultural field under investigation. It was estimated that around 2 x 10(7)Bq of (137)Cs were missing (around 30% of the total initial fallout) and were exported by physical processes (runoff and erosion processes) from the area under investigation. The cross-validation analysis showed that in the case of spatially structured data, OK is a better interpolation method than IDW1 or IDW2 for the assessment of potential radioactive contamination and/or pollution. 相似文献
66.
Bernard Jean-Thomas Hussain Jakir Sinha Mishaal Masud 《Environmental Economics and Policy Studies》2020,22(2):109-126
Environmental Economics and Policy Studies - We capitalize on access to plant-level data in examining the changes in emissions of biochemical oxygen demand (BOD), total suspended solids (TSS), and... 相似文献
67.
Karen Filkins M.D. F.A.C.O.G. Joseph Russo Thomas Brown Susan Schmerler Bernard Searle 《黑龙江环境通报》1984,4(3):223-226
Thirty-one genetic amniocenteses involving multiple gestations were performed in the genetics unit between 1976 and 1982. Three sets of triplets were included. Precise locations of the sacs were determined using real-time ultrasonography and successful sampling of all sacs was accomplished. Spontaneous abortions occurred in two normal twins and one normal triplet gestation. Two therapeutic abortions were performed for fetal abnormalities. Two cases of discordance for trisomy 21 (one twin and one triplet) were allowed to continue; the twin case terminated at 25 weeks' gestation with neonatal deaths and the triplets are alive and well. 相似文献
68.
Bernard?L.?CohenEmail author Nadia?Améziane Marc?Eleaume Bertrand?Richer?de?Forges 《Marine Biology》2004,144(3):605-617
We describe the first molecular and morphological analysis of extant crinoid high-level inter-relationships. Nuclear and mitochondrial gene sequences and a cladistically coded matrix of 30 morphological characters are presented, and analysed by phylogenetic methods. The molecular data were compiled from concatenated nuclear-encoded 18S rDNA, internal transcribed spacer 1, 5.8S rDNA, and internal transcribed spacer 2, together with part of mitochondrial 16S rDNA, and comprised 3,593 sites, of which 313 were parsimony-informative. The molecular and morphological analyses include data from the bourgueticrinid Bathycrinus; the antedonid comatulids Dorometra and Florometra; the cyrtocrinids Cyathidium, Gymnocrinus, and Holopus; the isocrinids Endoxocrinus, and two species of Metacrinus; as well as from Guillecrinus and Caledonicrinus, whose ordinal relationships are uncertain, together with morphological data from Proisocrinus. Because the molecular data include indel-rich regions, special attention was given to alignment procedure, and it was found that relatively low, gene-specific, gap penalties gave alignments from which congruent phylogenetic information was obtained from both well-aligned, indel-poor and potentially misaligned, indel-rich regions. The different sequence data partitions also gave essentially congruent results. The overall direction of evolution in the gene trees remains uncertain: an asteroid outgroup places the root on the branch adjacent to the slowly evolving isocrinids (consistent with palaeontological order of first appearances), but maximum likelihood analysis with a molecular clock places it elsewhere. Despite lineage-specific rate differences, the clock model was not excluded by a likelihood ratio test. Morphological analyses were unrooted. All analyses identified three clades, two of them generally well-supported. One well-supported clade (BCG) unites Bathycrinus and Guillecrinus with the representative (chimaeric) comatulid in a derived position, suggesting that comatulids originated from a sessile, stalked ancestor. In this connection it is noted that because the comatulid centrodorsal ossicle originates ontogenetically from the column, it is not strictly correct to describe comatulids as unstalked crinoids. A second, uniformly well-supported clade contains members of the Isocrinida, while the third clade contains Gymnocrinus, a well-established member of the Cyrtocrinida, together with the problematic taxon Caledonicrinus, currently classified as a bourgueticrinid. Another cyrtocrinid, Holopus, joins this clade with only weak molecular, but strong morphological support. In one morphological analysis Proisocrinus is weakly attached to the isocrinid clade. Only an unusual, divergent 18S rDNA sequence was obtained from the morphologically strange cyrtocrinid Cyathidium. Although not analysed in detail, features of this sequence suggested that it may be a PCR artefact, so that the apparently basal position of this taxon requires confirmation. If not an artefact, Cyathidium either diverged from the crinoid stem much earlier than has been recognised hitherto (i.e., it may be a Palaeozoic relic), or it has an atypically high rate of molecular evolution.Electronic Supplementary Material Supplementary material is available in the online version of this article at
Communicated by J.P. Thorpe, Port Erin 相似文献
69.
Ning Liu Jatin Kal Shirong Liu Vanessa Haver Bernard Dell Keith R.J. Smettem Richard J. Harper 《环境科学学报(英文版)》2020,32(4):262-274
Increasing atmospheric CO2 is both leading to climate change and providing a potential fertilisation effect on plant growth. However, southern Australia has also experienced a significant decline in rainfall over the last 30 years, resulting in increased vegetative water stress. To better understand the dynamics and responses of Australian forest ecosystems to drought and elevated CO2, the magnitude and trend in water use efficiency (WUE) of forests, and their response to drought and elevated CO2 from 1982 to 2014 were analysed, using the best available model estimates constrained by observed fluxes from simulations with fixed and time-varying CO2. The ratio of gross primary productivity (GPP) to evapotranspiration (ET) (WUEe) was used to identify the ecosystem scale WUE, while the ratio of GPP to transpiration (Tr) (WUEc) was used as a measure of canopy scale WUE. WUE increased significantly in northern Australia (p < 0.001) for woody savannas (WSA), whereas there was a slight decline in the WUE of evergreen broadleaf forests (EBF) in the southeast and southwest of Australia. The lag of WUEc to drought was consistent and relatively short and stable between biomes (≤3 months), but notably varied for WUEe, with a long time-lag (mean of 10 months). The dissimilar responses of WUEe and WUEc to climate change for different geographical areas result from the different proportion of Tr in ET. CO2 fertilization and a wetter climate enhanced WUE in northern Australia, whereas drought offset the CO2 fertilization effect in southern Australia. 相似文献
70.
Elzbieta Weryszko-Chmielewsk Idalia Kasprzyk Malgorzata Nowak Aneta Sulborsk Joanna Kaczmarek Agata Szymansk Weronika Haratym Miroslaw Gilski Malgorzata Jedryczka 《环境科学学报(英文版)》2018,30(3):271-281
The spores of Cladosporium Link. are often present in the air in high quantities and produce many allergenic proteins, which may lead to asthma. An aerobiological spore monitoring program can inform patients about the current spore concentration in air and help their physicians determine the spore dose that is harmful for a given individual. This makes it possible to develop optimized responses and propose personalized therapy for a particular sensitive patient. The aim of this study was to assess the extent of the human health hazard posed by the fungal genus Cladosporium. For the first time, we have determined the number of days on which air samples in Poland exceeded the concentrations linked to allergic responses of sensitive patients, according to thresholds established by three different groups(2800/3000/4000 spores per 1 m~3 of the air). The survey was conducted over three consecutive growing seasons(April–September, 2010–2012) in three cities located in different climate zones of Poland(Poznan, Lublin and Rzeszow). The average number of days exceeding 2800 spores per cubic meter(the lowest threshold) ranged from 61(2010) through 76(2011) to 93(2012), though there was significant variation between cities. In each year the highest concentration of spores in the air was detected in either Poznan or Lublin, both located on large plains with intensive agriculture. We have proposed that an effective, science-based software platform to support policy-making on air quality should incorporate biological air pollutant data,such as allergenic fungal spores and pollen grains. 相似文献