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261.
262.
263.
Journal of Material Cycles and Waste Management - Ports and marine transportation play important roles in the development of Vietnam, but there are increasing concerns over environmental issues... 相似文献
264.
M. Matabos E. Thiébaut D. Le Guen F. Sadosky D. Jollivet F. Bonhomme 《Marine Biology》2008,153(4):545-563
Three different molecular markers (i.e. seven allozyme loci, two nuclear gene loci and, mtCOI DNA sequences) were used to
assess the genetic structure of the vent gastropod Lepetodrilus elevatus collected from three vent fields along the East Pacific Rise (13°N, 9°50′N and 17°S). While allozymes and nuclear loci suggested
a strong stepping-stone pattern, a multivariate analysis performed on allozymic frequencies showed the presence of two distinct
evolutionary lineages: the first situated in the north from 13°N to 9°50′N and the second in the south from 9°50′N to 17°S.
The analysis of mitochondrial DNA sequences confirmed the separation of L. elevatus into two distinct clades with a divergence of 6.5%, which is consistent with the interspecific level of sequence variation
in other vent species. A divergence time of 6–14 Mya was estimated between the two clades from previous clock calibrations.
Our results suggest that these taxa followed an allopatric speciation between the northern and southern parts of the EPR with
a recent demographic expansion of the southern clade to the north and a subsequent secondary contact (clade hybridisation).
This speciation was probably reinforced by a habitat specialisation of the two cryptic species because the southern clade
was mainly found associated with mussel-dominated communities and the northern clade with tubeworm-dominated communities.
However, the analysis of shell morphology failed to separate the two cryptic species based on this sole criterion although
they differed from Lepetodrilus elevatus galriftensis (Galapagos population) by a higher shell elevation. Within each clade, genetic differentiation was not related to the distance
across populations and could be within vent field as important as between fields. While both clades appear to be in expansion
since their speciation, significant excesses in heterozygotes suggest a very recent and local bottleneck at 17°S, probably
due to massive site extinction in this region. 相似文献
265.
The degradation of 2,2′,4,4′-tetrabromodiphenyl ether(BDE-47) by Pycnoporus sanguineus was investigated in order to explore the impact of the heavy metal Cu~(2+) on BDE-47 decomposition and the subsequent formation of metabolites, as well as to further elucidate the degradation mechanism of BDE-47. An increase in degradation rate from 18.63% to49.76% in the first four days and its stabilization at(51.26 ± 0.08)% in the following days of BDE-47 incubation were observed. The presence of Cu~(2+) at 1 and 2 mg/L was found to promote the degradation rate to 56.41% and 60.79%, respectively, whereas higher level of Cu~(2+) (≥ 5 mg/L) inhibited the removal of BDE-47. The similar concentration effects of Cu~(2+) was also found on contents of fungal protein and amounts of metabolites. Both intracellular and extracellular enzymes played certain roles in BDE-47 transportation with the best degradation rate at 27.90% and 27.67% on the fourth and third day, individually. During the degradation of BDE-47, four types of hydroxylated polybrominated diphenyl ethers(OH-PBDEs), i.e., 6′-OH-BDE-47, 5′-OH-BDE-47, 4′-OH-BDE-17, 2′-OH-BDE-28, and two bromophenols, i.e., 2,4-DBP and 4-BP were detected and considered as degradation products. These metabolites were further removed by P. sanguineus at rates of 22.42%,23.01%, 27.04%, 27.96%, 64.21%, and 40.62%, respectively. 相似文献
266.
Sabina Toś-Luty Janina Halliop Jadwiga Latuszyńska Maciej Latalski Alina Tochman Daniela Obuchowska 《International journal of occupational safety and ergonomics》2013,19(2):167-178
We studied the effect of chlorfenvinphos dermal absorption on the morphological picture of blood, on the histological and fine structure of tail skin, and on the histological structure of internal organs (lungs, heart, liver, spleen, and kidney) of rats. This study was conducted on 25 white Wistar rats, the tail skin of which was—or was not—hydrated before exposure. Rat tails were soaked in 0.5% or 0.05% chlorfenvinphos for 1 hr day for 3 months. Evident tendencies for a decrease in the absolute level of leukocytes and for an increase in the absolute level of erythrocytes in all experimental animals were observed. Histopathological changes in the internal organs were mildly manifested in only a few rats, mainly as liver and pulmonary hyperaemia. Rat tail skin at the direct exposure site showed hyperceratosis, intensive desquamation, and compensatory hyperplasia. 相似文献
267.
Tran?Duc?ThanhEmail author Yoshiki?Saito Dinh?Van?Huy Van?Lap?Nguyen Thi?Kim?Oanh?Ta Masaaki?Tateishi 《Regional Environmental Change》2004,4(1):49-62
Vietnam is a tropical to subtropical country located on the eastern Asian coast where the Red (Song Hong) and Mekong rivers discharge into the sea. The catchments of these two transboundary rivers cover parts of six countries, and their water and sediment discharges greatly influence the coastal seas of Vietnam. The impact of human activities include changes in the supply and distribution of water, sediments, and nutrients; changes in the relationships and balance among dynamically interacting factors and processes; and changes in the quality of the coastal and marine environments due to the increased use and accumulation of pollutants and the loss of habitats. These impacts have resulted in increasing unpredictability and severity of coastal problems such as floods, erosion, sedimentation, and saltwater intrusion; environmental pollution; and the degradation of ecosystems, with accompanying decrease in biodiversity and fishery productivity. 相似文献
268.
Chakrabortty Rabin Pal Subodh Chandra Arabameri Alireza Ngo Phuong Thao Thi Chowdhuri Indrajit Roy Paramita Malik Sadhan Das Biswajit 《Environment, Development and Sustainability》2022,24(3):3518-3557
Environment, Development and Sustainability - The large-scale water-induced erosion is one of the most determining elements on land degradation in subtropical monsoon-dominated region. From this... 相似文献
269.
Huong Do Thi Thu Ha Nguyen Thi Thu Do Khanh Gia Van Thanh Nguyen Hens Luc 《Environment, Development and Sustainability》2022,24(4):5032-5051
Environment, Development and Sustainability - The Northeastern coastal zone of Vietnam possesses high biodiversity and rich ecosystems like coral reefs, seagrasses, beaches and mangroves. It also... 相似文献
270.
Patrick Hohlfeld Thi-Tan Dang K. Nahoul Fernand Daffos François Forestier 《黑龙江环境通报》1994,14(10):907-912
Normal levels of cancer-associated antigen (CA) 19-9, neurone-specific enolase (NSE), cancer-associated antigen (CA) 125, and mucin-like carcinoma-associated antigen (MCA) during pregnancy were determined in 87 mothers and fetuses, using a solid-phase sandwich enzyme immunoassay. CA 19-9 concentrations were higher in the fetuses, whereas the other three tumour-associated antigen levels were higher in the mothers. Only fetal NSE and MCA levels were positively correlated with those in maternal serum. Contrary to adult samples, no difference was demonstrated between male and female fetal levels of CA 125. MCA was the only maternal marker that increased significantly with gestational age between 20 and 34 weeks' pregnancy. 相似文献