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121.
Regional Environmental Change - This paper synthesizes what is known about the physical and biophysical impacts of climate change and their consequences for societies and development under...  相似文献   
122.
Environmental Science and Pollution Research - Coal mining and burning activities in coal-fired power plants are among the most polluting activities in developing countries. In Brazil, the Candiota...  相似文献   
123.
东非珊瑚礁的特点是它位于一个离散的动物地理学分区[1],具有经由赤道流接纳和重新分配偏远的种属物质的潜在重要性[2].尽管如此,该地区仍然是世界上研究最少的地区之一.例如,在坦桑尼亚,尽管珊瑚礁是众多的人赖以为生的重要自然资源,却没有受到应有的重视和研究[3~5].为数不多的研究定量分析过坦桑尼亚的珊瑚礁结构[6~13],而且大部分只是限于对一些礁砰进行基线研究.  相似文献   
124.
Environmental Science and Pollution Research - There are inconsistent reports on the association between air pollution and cancers. This systematic review was, therefore, conducted to ascertain the...  相似文献   
125.
Offshore windmills and the effects of electromagnetic fields on fish   总被引:1,自引:0,他引:1  
Ohman MC  Sigray P  Westerberg H 《Ambio》2007,36(8):630-633
With the large scale developments of offshore windpower the number of underwater electric cables is increasing with various technologies applied. A wind farm is associated with different types of cables used for intraturbine, array-to-transformer, and transformer-to-shore transmissions. As the electric currents in submarine cables induce electromagnetic fields there is a concern of how they may influence fishes. Studies have shown that there are fish species that are magneto-sensitive using geomagnetic field information for the purpose of orientation. This implies that if the geomagnetic field is locally altered it could influence spatial patterns in fish. There are also physiological aspects to consider, especially for species that are less inclined to move as the exposure could be persistent in a particular area. Even though studies have shown that magnetic fields could affect fish, there is at present limited evidence that fish are influenced by the electromagnetic fields that underwater cables from windmills generate. Studies on European eel in the Baltic Sea have indicated some minor effects. In this article we give an overview on the type of submarine cables that are used for electric transmissions in the sea. We also describe the character of the magnetic fields they induce. The effects of magnetic fields on fish are reviewed and how this may relate to the cables used for offshore wind power is discussed.  相似文献   
126.
Drosophila melanogaster is today one of the three foremost models in olfactory research, paralleled only by the mouse and the nematode. In the last years, immense progress has been achieved by combining neurogenetic tools with neurophysiology, anatomy, chemistry, and behavioral assays. One of the most important tasks for a fruit fly is to find a substrate for eating and laying eggs. To perform this task the fly is dependent on olfactory cues emitted by suitable substrates as e.g. decaying fruit. In addition, in this area, considerable progress has been made during the last years, and more and more natural and behaviorally active ligands have been identified. The future challenge is to tie the progress in different fields together to give us a better understanding of how a fly really behaves. Not in a test tube, but in nature. Here, we review our present state of knowledge regarding Drosophila plant-odor-related olfactory neuroethology to provide a basis for new progress.  相似文献   
127.
N. H. Marcus 《Marine Biology》1990,104(3):413-418
In Ireland, mussels on exposed rocky shores constitute an interbreeding mixture of two forms of mussels,Mytilus edulis L. and the Mediterranean musselM. galloprovincialis Lmk. This paper presents an in-depth analysis, carried out between October 1984 and December 1986, of genetic variability at two partially diagnostic loci,Odh andEst-D, in two exposed-shore populations ofMytilus spp. in the west of Ireland. Significant differences at theOdh locus were observed in the genetic composition of adult mussels from different tidal levels. These differences were repeatable whether one was analysing replicate samples at a single point in time, samples collected at different points in time, i.e., in different years, or samples collected from different shores. Mussels recruiting to artificial substrates set out for a period of one month at different tidal levels at one of these sites were also observed to be genetically different; mussels higher up the shore exhibited higher frequencies of those alleles characteristically at high frequency inM. galloprovincialis for both theOdh andEst-D loci. Hence, the genetic differences observed in adult mussels are much more exaggerated in juveniles and are already apparent within the first month of benthic life. Possible reasons for the observed microgeographic differentiation are discussed. It is concluded that the observed genetic differences between mussels at different tidal levels arise either in the pelagic/attachment stage or very shortly after settlement.  相似文献   
128.
Two actin genes named actinT1 and actinT2 were isolated and sequenced from the Pacific white shrimp, Litopenaeus vannamei, by screening from a shrimp eyestalk cDNA library. L. vannamei actinT1 cDNA has a 1,128-bp open reading frame encoding for 376 amino acids while L. vannamei actinT2 cDNA has a 1,131-bp open reading frame coding for 377 amino acids. Alignment of the actinT1 and actinT2 cDNA sequences showed that these two actin genes share a sequence identity of 86% at amino acid residues. When compared with actins of several other invertebrate and vertebrate species, the nucleotide sequence of actinT1 is highly homologous (97–100%) with beta-actins, while actinT2 shares 86–95% identity with alpha-actins on the nucleotide level. Phylogenetic analysis and BLAST searches indicated that the ActinT1 protein is identical to crustacean beta-actins, while the ActinT2 protein is highly homologous to crustacean alpha-actins. Constitutive expression of the actinT1 and actinT2 genes were detected by RT-PCR in all adult shrimp organs, including brain, eye-stalk, gill, heart, hemolymph, hepatopancreas, muscle, swimming legs, and stomach, as well as in the shrimp zygote, nauplius, and mysis life stages. These data will facilitate attempts to clone and identify more shrimp genes and constitutive shrimp promoters.  相似文献   
129.
The recycling of nitric acid and copper nitrate contained in an industrial effluent was studied. The experiments conducted on such a medium showed that the presence of copper nitrate significantly improves nitric acid-water separation during distillation in an azeotropic medium. At the temperature of the azeotrope, however, this metal salt starts to precipitate, making the medium pasty, thus inhibiting the nitric acid extraction process. The optimisation of parameters such as column efficiency and adding water to the boiler at the azeotrope temperature are recommended in this protocol in order to collect the various components while avoiding the formation of by-products: NOx compounds. Thus, the absence of column, along with the addition of a small volume of water at a temperature of 118 °C, significantly increases the yield, allowing 94 % nitric acid to be recovered at the end of the process, along with the residual copper nitrate. The resulting distillate, however, is sufficiently dilute to not be used as is. Rectification is required to obtain concentrated nitric acid at 15 mol·l?1, along with a weakly acidic distillate from the distillation front. This latter is quenched using potassium hydroxide and is used as a fertiliser solution for horticulture or sheltered market gardening. This process thus allows complete recycling of all the medium’s components, including that of the distillate resulting from the nitric acid rectification operation.  相似文献   
130.
The objective of this research was to study population dynamics of the weed crabgrass, genus Digitaria, submitted to selection pressure by herbicides currently applied in sugarcane crops in Brazil. In the first experiment two crabgrass species (Digitaria nuda and Digitaria ciliaris) and eight herbicide treatments applied in preemergence were used, and control percentage was evaluated at 7, 14, and 21 days after herbicide application (DAA). In the second experiment the level of tolerance through dose-response curve was determined for the species D. nuda and D. ciliaris, to the herbicides imazapyr, tebuthiuron, ametryne, and metribuzin. All the herbicides studied were efficient in controlling D. ciliaris, however, for D. nuda the best results were obtained only with ametryne, metribuzin, and isoxaflutole. The relation (T/S) between the rate required to reduce plant dry biomass (GR50) at 21 DAA of D. nuda and D. ciliaris was 16 for imazapyr and 6.3 for tebuthiuron, showing differential susceptibility of species; however for ametryne the rate T/S of 1.1 showed that D. nuda was not tolerant to this herbicide. For metribuzin, at 1.92 kg a.i. ha(-1), reduction of dry biomass was 80 and 90% to D. nuda and D. ciliaris, respectively. Even being controlled by metribuzin, D. nuda presented a higher level of tolerance to this herbicide, what was confirmed by the relationship T/S 14.4. As general conclusion of the research, it can be stated that the species D. nuda is more tolerant to ALS inhibiting herbicides and substituted urea, when compared with D. ciliaris; probably, D. nuda was selected by repetitive use of these herbicides.  相似文献   
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