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121.
Hazardous industrial sites have always represented a threat for the community often provoking major accidents overcoming the boundaries of the plants and affecting the surrounding urban areas. If the industrial sites are located in natural hazard-prone areas, technological accidents may be triggered by natural events, generating so-called na-tech events which may modify and increase the impact and the overall damage in the areas around them. Nevertheless, natural and technological hazards are still treated as two separate issues, and up to now the methods for na-tech risk assessment have been developed mainly for specific natural hazards, generally restricted to some plant typologies and to the area of the plant itself. Based on a review of the current na-tech literature, this article illustrates a risk assessment method as a supporting tool for land use planning strategies aimed at reducing na-tech risk in urban areas. More specifically, a multi attribute decision-making method, combined with fuzzy techniques, has been developed. The method allows planners to take into account, according to different territorial units, all the individual na-tech risk factors, measured through both quantitative and qualitative parameters, while providing them with a na-tech risk index, useful to rank the territorial units and to single out the priority intervention areas. The method is designed to process information generally available about hazardous plants (safety reports), natural hazards (hazard maps) and features of urban systems mainly influencing their exposure and vulnerability to na-tech events (common statistical territorial data). Furthermore, the method implemented into a GIS framework should easily provide planners with comparable maps to figure out the hazard factors and the main territorial features influencing the exposure and vulnerability of urban systems to na-tech events. The method has been tested on a middle-sized Municipality in the Campania Region, identified as 2nd class seismic zone, according to the Ordinance 3274/2003, in which a LPG storage plant, classified as a plant with major accident potential by the Seveso II Directive (art. 9), is located just within the city core.  相似文献   
122.
Ecological and biogeographical studies of Neotropical non-marine ostracods are rare, although such information is needed to develop reliable paleoecological and paleoclimatic reconstructions for the region. An extensive, yet little explored South American area of paleoclimatic interest, is the arid-semiarid ecotone (Arid Diagonal) that separates arid Patagonia from subtropical/tropical northern South America, and lies at the intersection of the Pacific and Atlantic atmospheric circulation systems. This study focused on the Laguna Llancanelo basin, Argentina, a Ramsar site located within the Arid Diagonal, and was designed to build a modern dataset using ostracods (diversity, spatial distribution, seasonality, habitat preferences) and water chemistry. Cluster and multivariate analysis of the data indicated that salinity is the most significant variable segregating two ostracod groups. Limnocythere aff. staplini is the only species that develops abundant populations in the saline ephemeral Laguna Llancanelo during almost all seasons, and is accompanied by scarce Cypridopsis vidua in summer. The latter species is abundant in freshwater lotic sites, where Ilyocypris ramirezi, Herpetocypris helenae, and Cyprididae indet. are also found in large numbers. Darwinula stevensoni, Penthesilenula incae, Heterocypris incongruens, Chlamydotheca arcuata, Chlamydotheca sp., Herpetocypris helenae, and Potamocypris smaragdina prefer freshwater lentic conditions (springs), with C. arcuata and Chlamydotheca sp. found only in the Carapacho warm spring, which has a year-round constant temperature of ~20 °C. Seasonal sampling was necessary because some taxa display a highly seasonal distribution. Species that were recorded have either subtropical or Patagonian affinities, although a few taxa are endemic or common to both regions. These data can serve as modern analogues for reconstructing the late Quaternary history of the area, and to investigate the extent and position of the arid/semiarid ecotone (Arid Diagonal) during past glacial/interglacial cycles.  相似文献   
123.
We evaluated the effectiveness of chemical tagging with the fluorescent marker calcein for two key species of herbivorous sea urchins, Diadema africanum and Paracentrotus lividus, to facilitate medium‐ and long‐term ecological experiments. In total, 98 juveniles of Dafricanum and 98 Plividus were tagged with this fluorescent marker, with 12 combinations of different tagging techniques (chemical bath or injection), concentrations of calcein (2, 10 and 20 mg · l?1), and soaking times (2, 4 and 24 h). Respective control treatments were conducted by means of seawater injection and bathing. The success of tagging was assessed after a month of feeding individuals ad libitum with the algae Dictyota sp. Sea urchins were dissected and their Aristotle's lanterns cleaned with 10% sodium hypochlorite to examine these structures under UV light using a binocular microscope. Each species was evaluated in terms of survival, percentage of tagged individuals and intensity of the resulting tag. The results showed that the method of soaking individuals of both species for 24 h in concentrations of calcein of 10 and 20 mg · l?1 gave the highest percentage survival (100%) and the resulting tags were clearly visible.  相似文献   
124.
In this study, we examined the bacterial accumulation in the filter feeder polychaete Branchiomma luctuosumGrube (Sabellidae). Analyses were performed on worm homogenates from 'unstarved' and 'starved' individuals, and seawater from the same sampling site (Gulf of Taranto, Western Mediterranean, Italy). Densities of culturable heterotrophic bacteria (22 degrees C), total culturable bacteria at 37 degrees C and halophilic vibrios at 22 and 35 degrees C were measured on Marine Agar 2216, Plate Count Agar and thiosulphate-citrate-bile-salt-agar (TCBS) plus 2% NaCl, respectively. Total and faecal coliforms as well as faecal streptococci were determined by the Most Probable Number method. Results showed that B. luctuosum is able to accumulate all the considered six microbiological groups with a higher efficiency for autochthonous bacteria. The analysis also indicated that bacterial groups differ in their resistance to digestion by B. luctuosum. Our data suggest the potential role of B. luctuosum as an useful bioindicator to assess low levels of microbiological water pollution as well as bioremediator of microbial polluted waters.  相似文献   
125.
126.
The last 16 000 cal. a of vegetation, fire and limnological history are described from the steppe‐forest ecotone in the northernmost Nothofagus forest region east of the Andes (Mallín Vaca Lauquen, Neuquén Province, Argentina, latitude 36° 51.336′ S, longitude 71° 02.538′ W). Between 16 000 and 14 800 cal. a BP, scrub steppe with substantial open ground expanded in formerly glaciated valleys, whereas NothofagusPrumnopitys andina woodland covered mountain slopes. The site was a relatively deep and unproductive small lake at this time. After 14 800 cal. a BP, both steppe and woodland vegetation became denser, indicating increased moisture and temperatures, although not to present levels. The lake was still relatively deep and dystrophic, but became more alkaline by 10 000 cal. a BP. Between 8900 and 5500 cal. a BP, conditions were markedly drier than before; a Cyperaceae marsh developed and disturbance taxa increased. After 5500 cal. a BP, moisture increased but varied greatly, as evidenced by fluctuating water levels and high fire activity from 5500 to 4400 cal. a BP and from 2300 to 1000 cal. a BP. Human activity, in terms of forest clearance and livestock grazing, is documented in the uppermost levels. The evidence of high environmental variability in the middle and late Holocene is consistent with the onset or strengthening of the El Niño–Southern Oscillation, but differences in the timing of fire activity among sites on the west and east sides of the Andes suggest that fuel conditions were important in determining the local occurrence of fire. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
127.
The synoptic charts of the filaments and active regions near the solar limb are given for the eclipse of November 3, 1994, along with the positions of the prominences. A table helps to associate coronal and chromospheric structures.  相似文献   
128.
The distribution and composition of four benthic foraminifera assemblages from the Guaymas Basin are depicted through Q- and R-mode Factor Analysis. One of these assemblages is distributed near hydrothermal vents,* another developed away from the influence of the vents, and the other two assemblages are found in the subbottom sediments.Biostratigraphic analysis of five cores collected within the hydrothermal region suggest that the foraminiferal remains have been affected by aselective dissolution process. Only small species, such asBulimina spinosa andBolivina sp 2, have been preserved in the subbottom sediments which have been influenced by the hydrothermal activity.  相似文献   
129.
Dissolved organic matter (DOM) is comprised of a myriad of macromolecules with specific physical and chemical properties that may influence the bioavailability of hydrophobic pesticides to animals. This study was conducted to assess the role of various forms of DOM on the uptake and bioconcentration of the organophosphate insecticide chlorpyrifos (CHPY) to the bivalve Mercenaria mercenaria. Bivalves were exposed to DOM-free seawater (30 per thousand) or to seawater containing a single form of DOM. DOM forms included two filtrate fractions of natural salt-marsh sediment DOM (DOM-(<0.45 mum) and DOM-(<3 kDa)); natural purified humic (HA) and fulvic (FA) acids; and water soluble cyclic oligosaccharides alpha and beta cyclodextrins (CD-alpha and CD-beta). In (14)C-CHPY uptake and elimination experiments, juvenile bivalves were exposed to uniformly-labeled (14)C-CHPY and collected at time intervals during 48 h. The remaining bivalves were transferred to (14)C-CHPY-free elimination chambers with bivalve collection at time intervals over 144 h. Total uptake of (14)C-CHPY by bivalves in DOM-free seawater was >40% greater than in bivalves exposed to (14)C-CHPY in the presence of most DOM forms. These results are consistent with much faster (14)C-CHPY uptake rates estimated using a simple two parameter model. After the elimination period, bivalves exposed to DOM-free seawater had (14)C-CHPY body residue concentrations between 25% and 86% greater than bivalves in the presence of DOM forms. Experiments with larger bivalves showed that pulse-chase exposures with a 1.5 h exposure period to (14)C-CHPY was not long enough to detect differences in (14)C-CHPY tissue accumulation efficiencies across treatments. Our findings suggest that natural forms of DOM, at environmentally realistic organic carbon concentrations, reduced pesticide uptake and bioconcentration, consistent with much lower uptake rates relative to bivalves exposed to (14)C-CHPY in the absence of DOM. Interestingly, at the tested organic carbon concentrations CD-alpha and CD-beta did not reduce (14)C-CHPY bioconcentration in M. mercenaria.  相似文献   
130.
Abstract. Thirteen sampling cruises were conducted at weekly intervals in the inner part of the Gulf of Naples in the summer of 1983 to investigate the effects of excess nutrient inputs on phytoplankton communities. High surface phytoplankton concentrations (up to 1.15 ×108 cells 1-1) were recorded, particularly near Naples harbour and along the eastern coast, two locations that receive most of the area's sewage and industrial discharge. Phytoplankton populations were generally dominated by small species, mainly diatoms, which were associated with small phytoflagcllatcs. Species diversity values were relatively high (H'≤ 3.62) in most samples. Throughout the sampling period a high spatial and temporal variability for phytoplankton abundances and species composition was observed.  相似文献   
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