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1.
The succession of drought years and excessive abstraction in the plain of Triffa caused deterioration in water quality and endangers future exploitation of groundwater resources. A combination of geophysical surveys, including electrical resistivity and hydrochemical data has been used to identify the geographical extension of salinization and identify its origin. Electrical conductivity measurements are used to show the history of salinization in space and time. In this paper, a first conceptual model of the brackish springs has been established. To cite this article: M. Boughriba et al., C. R. Geoscience 338 (2006).  相似文献   
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The impact of the air pollution generated by any industrial activities may be further aggravated if the location of the industrial area is exposed to certain atmospheric characteristics. Under such conditions, the likelihood of accumulation of local air pollution is high. This paper uses two approaches (statistical and numerical simulation) to investigate the contribution of atmospheric processes towards degradation of air quality. A case study of the two approaches was conducted over Sohar Industrial Area in the Sultanate of Oman. Measured wind data were used to account for specific atmospheric characteristics such as stagnation, ventilation, and recirculation using the statistical approach. In the second approach, numerical weather prediction model was used to simulate mesoscale circulation phenomena such as sea breeze and its contribution to the processes affecting the air quality. The study demonstrates that the atmospheric processes appear to contribute substantially to the degradation of air quality in the Sohar Industrial Area. The statistical analysis shows that the atmospheric dilution potential of Sohar Industrial Area is prone to stagnation and recirculation, rather than ventilation. Moreover, model simulation shows that there is a seasonal variation in the contribution of atmospheric processes to the degradation of the air quality at Sohar Industrial Area.  相似文献   
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The Agadir-Essaouira area in the occidental High Atlas Mountains of Morocco is characterized by a semi-arid climate. The scarcity and quality of water resources, exacerbated by long drought periods, constitute a major problem for a sustainable development of this region. Groundwater resources of carbonate units within Jurassic and Cretaceous aquifers are requested for drinking and irrigation purposes. In this study, we collected 84 samples from wells, boreholes, springs, and rivers. Hydrochemical and isotopic data were used to examine the mineralization and origin of water, which control groundwater quality. The chemical composition of water seems to be controlled by water-rock interactions, such as dissolution of carbonates (calcite and dolomite), weathering of gypsum, as well as ion exchange processes, which explain the observed variability. Stable isotopes results show that groundwater from the mainly marly Cretaceous aquifer are submitted to an evaporation effect, while samples from the chiefly calcareous Jurassic aquifer indicate a meteoric origin, due to a rapid infiltration of recharge runoff through the karstic outcrops. The low values of δ18O and δ2H suggest a local recharge from areas with elevations ranging from 400 to 1200 m for the Cretaceous aquifer and from 800 to 1500 m for the Jurassic units.  相似文献   
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Concentrations of ten polybrominated diphenyl ethers (PBDEs) and eight methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) collected from the Bizerte Lagoon and the Mediterranean Sea were investigated. To the best of our knowledge, this is the first report of these compounds in marine fishes from Tunisia. The PBDE mean concentrations in fish from Bizerte Lagoon were 45.3 and 96.2 ng g(-1) lw respectively in mullet and sea bass, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea were 7.80 and 27.9 ng g(-1) lw respectively. MeO-PBDE concentrations in mullet and sea bass from Bizerte Lagoon ranged from 6.46 to 286 ng g(-1) lw and from 49.4 to 798 ng g(-1) lw respectively, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea ranged from 190 to 401 ng g(-1) lw and from 353 to 578 ng g(-1) lw respectively. The total PBDEs and total MeO-PBDEs concentration in fish from Bizerte Lagoon were similar or slightly lower than those reported for other species from other locations around the world.  相似文献   
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This paper presents a rather complete picture of conditions of stagnation, recirculation and ventilation factors in the main industrialized and urban areas in Oman, developed along the coastal area. This study focuses on four sites; Sohar, Muscat, Sur, and Salalah. Each site has a local emission sources from transportation, industry and energy production activities. For the calculation of the integral quantities of the ability of the atmosphere dilution, hourly data of the wind velocity measured at a height of 10 m during 5 years (2000–2005) were used in the analysis. The results show that in the northern coast of Oman, along the bay of Sea of Oman, where 56% of the total population is concentrated and the main heavy industries of the country are amassed, the atmosphere is prone to stagnations in 74.4% of the time, while in the southern and east part of Oman, they occur only 23% and 51%, respectively. The bay of sea of Oman is high affected by land–sea breeze circulation that plays a substantial role in the simultaneous occurrence of recirculation equally to stagnation. This meso-scale effect is altered gradually during the passage of the synoptic-scale flow of the southeasterly summer monsoon that enhances the occurrence of the ventilation in Salalah (24.6% of time) and Sur (15.5%). In the northern coast of Oman, where the Hajir mountains suppressed the effect of the summer monsoon, a very weak tendency towards ventilation is observed (less than 6%). The southern summer monsoon over Oman is a source of life in this arid area and as well a source of clean air.  相似文献   
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Located at the northeastern part of Morocco, the plain of Triffa is characterized by a semi-arid climate where water resources are rather fragile and influenced by a highly irregular rainfall distribution, both in time (annual and inter-annual distribution) and in space. The mean annual rainfall does not exceed 240 mm. In the Triffa plain, the impact of anthropogenic activities on the groundwater resources is reflected both by (a) the decrease in the piezometric level due to the over exploitation and droughts and (b) the deterioration of the chemical quality of water. Currently, this situation is felt mainly by the farmers. The unconfined aquifer is under stress due to the increase of the pollution rate, especially by nitrates that are above the WHO standards, and salinity. Organochlorine pesticides are ubiquitous and persistent organic pollutants used widely in agriculture. Due to their extensive use in agriculture, organic environment contaminants such as hexachlorocyclohexane, DDT, and DDD along organochlorine pesticides are distributed globally by transport through water. Pesticides such as aldrin, lindane, and heptachlor have also been detected and were considered as indicators showing the need to inform and to train farmers on the pesticides and fertilizers use in order to reduce the threat of groundwater contamination.  相似文献   
8.
ESA’s Gaia mission will collect low resolution spectroscopy in the optical range for ~109 objects. Complete and up-to-date libraries of synthetic stellar spectra are needed to built algorithms aimed to automatically derive the classification and the parametrization of this huge amount of data. In addition, libraries of stellar spectra are one of the main ingredients of stellar population synthesis models, aiming to derive the properties of unresolved stellar populations from their integrated light. We present (a) the newly computed libraries of synthetic spectra built by the Gaia community, covering the whole optical range (300–1100 nm) at medium-high resolution of (0.3 nm) for stars spanning the most different types, from M to O, from A-peculiar to Emission lines to White Dwarfs, and (b) the implementation of those libraries in our SSP code (Tantalo in The Initial Mass Function 50 Years Later, 327:235 2005), exploring different stellar evolution models.  相似文献   
9.
A density-dependent numerical groundwater model was applied to study the climate change impact in a shallow aquifer in the Mediterranean coast of Morocco, the Saïdia aquifer. The stresses imposed to the model were derived from the IPCC emission scenarios and included recharge variation and sea level rise. The main effect of the climate change in the Saïdia aquifer will be a decrease in renewable resources, which in the worst-case scenario may decrease to 50–60% of present-day values, due to the decline in recharge and to a reduced inflow from the adjacent Triffa aquifer. The water quality will be affected mostly in the area immediately adjacent to the seashore, where salinity may increase up to 30 g/l. Localised areas may see a decrease in salinity due to the induced freshwater recharge from Oued Moulouya River and diminished inflow from high-salinity springs.  相似文献   
10.
The indiscriminate use of antimicrobials especially in developing countries has evoked serious bacterial resistance and led to the emergence of new and highly resistant strains of bacteria to commonly used antimicrobials. In Lebanon, pollution levels and bacterial infections are increasing at a high rate as a result of inadequate control measures to limit untreated effluent discharges into the sea or freshwater resources. The aim of this study was to isolate and molecularly characterize various Staphylococcus strains isolated from sea water, fresh water, sediments, and crab samples collected from representative communities along the coast of Lebanon. The results on the antimicrobial resistance indicated that the level of resistance of Staphylococcus aureus varied with various antimicrobials tested. The resistance patterns ranged between 45% in freshwater isolates and 54.8% in seawater ones. Fifty one percent of the tested isolates have shown resistance to at least one of the five tested antimicrobials; with seawater isolates exhibiting the highest rates of antimicrobial resistance.  相似文献   
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