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41.
DNA damage and apoptosis in the mussel Mytilus galloprovincialis 总被引:4,自引:0,他引:4
The effects of known genotoxic substances (4-nitroquinoline-N-oxide, benzo[a]pyrene, teniposide, etoposide, cycloheximide, tributyltin) on human cells (FLC, HL-60) and on mussels were investigated. The correlations between formation of DNA strand breaks and DNA fragmentation characteristic for the process of apoptosis were estimated. Strand breaks induced by 4-nitroquinoline-N-oxide and benzo[a]pyrene did not correlate with DNA fragmentation detected in the process of apoptosis. Induction of internucleosomal DNA fragmentation in HL-60 cells was initiated by teniposide, etoposide and tributyltin, while in the gills of mussels this was detected only with tributyltin. Levels of DNA strand breaks in natural mussel populations, living at locations under the influence of urban and industrial wastes, do not mirror the apoptotic processes. 相似文献
42.
John E. Gordon Igor J. Dvorák Christer Jonasson Melanie Josefsson Milena Kociánová & Des B.A. Thompson 《Geografiska Annaler: Series A, Physical Geography》2002,84(3-4):193-203
Montane (alpine) areas are generally of high value for nature conservation. Such environments and the habitats they support are dynamic and often fragile. They are vulnerable to disturbance from a range of human activities and are responsive to climate changes over short and long timescales. Biodiversity and conservation values are closely linked to geological history, geomorphological processes and soils, and it is crucial that management systems are based on understanding these links.
There are many similarities between the Cairngorm Mountains (Scotland), the Giant Mountains (Czech Republic) and Abisko Mountains (Sweden) in terms of geology, geomorphology, ecology, links with biodiversity and high conservation importance. Comparable pressures and management issues involve, to varying degrees, a history of human use and impacts from deforestation, pasturing, grazing, recreation and atmospheric pollution. Landscape change therefore involves a complex interplay between natural and anthropogenic factors. Managing such change requires better understanding of the geo–ecological processes involved and the factors that determine landscape sensitivity. This is illustrated through a simple framework and examples from the three areas. Comparison of landscape sensitivity between similar montane areas, but in different geographic locations and climatic environments, should allow more informed management planning and a precautionary approach in advance of further changes in human activity and from predicted global warming scenarios. 相似文献
There are many similarities between the Cairngorm Mountains (Scotland), the Giant Mountains (Czech Republic) and Abisko Mountains (Sweden) in terms of geology, geomorphology, ecology, links with biodiversity and high conservation importance. Comparable pressures and management issues involve, to varying degrees, a history of human use and impacts from deforestation, pasturing, grazing, recreation and atmospheric pollution. Landscape change therefore involves a complex interplay between natural and anthropogenic factors. Managing such change requires better understanding of the geo–ecological processes involved and the factors that determine landscape sensitivity. This is illustrated through a simple framework and examples from the three areas. Comparison of landscape sensitivity between similar montane areas, but in different geographic locations and climatic environments, should allow more informed management planning and a precautionary approach in advance of further changes in human activity and from predicted global warming scenarios. 相似文献
43.
44.
Estimation of the elastic earth parameters using slr data for the low satellites STARLETTE and STELLA 总被引:1,自引:0,他引:1
In this paper we present estimated values for the global elastic parameters (k 2, k 3) and (h 2, l 2) derived from the analysis of Satellite Laser Ranging (SLR) data. We analyse SLR data for two low satellites, STARLETTE and STELLA, collected over a period of two years, from 1 January 2005 to 1 January 2007, from 18 globally distributed ground stations. We carry out a sequential analysis for the two satellites jointly, and study the stability of the estimates as a function of the length of the data set used. The adjusted final values of (k 2, k 3) and (h 2, l 2) for STARLETTE and STELLA are compared to, and are largely found to support, the estimates we previously published based on data for two high satellites LAGEOS 1 and LAGEOS 2. A major discrepancy between the two solutions was only found for the Shida number l 2. 相似文献
45.
Global changes in the marine environment and the continuing disposal of genotoxic xenobiotics are increasing the importance of environmental pollution monitoring and of biomonitoring programs. Current approaches focus on investigations at regional and local levels in an attempt to precisely define the nature and extent of any potential environmental crisis. We have initiated, for the first time, a long-term biomonitoring program focusing on the Croatian coast of the Adriatic Sea to contribute to a more detailed understanding of marine genotoxic effects using the mussels Mytilus galloprovincialis Lam., collected along the eastern Adriatic coast over a period of five years (1998-2002), as a key test organism. The integrity of DNA in its gill homogenate was examined by the Fast Micromethod. The strand scission factor (SSF) values, as a measure of DNA integrity, DNA damage or incomplete repair have been used for the ranking of sampling sites with respect to significant genotoxic stress due to the influence or effects of genotoxic xenobiotics. The region of Split (Kastela Bay) proved to be the area with the heaviest load of genotoxic agents. The investigation of harmful effects in the ecosystem based on biomonitoring of genetic and other agents, not only on local levels but also on a wider scale, is considered as an important step in marine environmental management. 相似文献
46.
The
ability of a regional climate model (RCM) to successfully reproduce the
fine-scale features of a regional climate during summer is evaluated using an
approach nick-named the “Big-Brother Experiment” (BBE). The BBE establishes a
reference virtual-reality climate with a RCM applied on a large and
high-resolution domain: this simulation is called the Big-Brother (BB)
simulation. This reference simulation is then downgraded by filtering
small-scale features that are unresolved in today’s global objective analyses.
The resulting fields are then used as nesting data to drive the same RCM, which
is integrated, at the same high resolution as the BB, only over a sub-area of
the larger BB domain, hence, producing the Little-Brother simulation (LB). With
the BBE approach, differences between the two simulated climates (BB and LB)
can be unambiguously attributed to errors associated with the dynamical
downscaling technique, and not to model errors or observational limitations.
The current study focuses on the summer over the West Coast of North America.
Results of the stationary and transient parts of the fields, decomposed by
horizontal scales, are presented for the month of July, for 5 consecutive years
(1990–1994). Three degrees of spatial filtering (roughly equivalent to the
global spectral resolution of T30, T60 and T360) as well as two update
intervals (3 and 6 h) of the lateral boundary conditions (LBC) have been
employed. This study establishes that the maximum acceptable resolution of
driving data for summer is T30, with improved results employing the T60
resolution of LBC. There is little improvement by reducing the time interval
from 6 h to 3 h. These results are generally in agreement with previous studies
carried out for winter. The good correlation between LB and BB simulations is
more difficult to achieve during the summer season, mostly due to weaker
control exerted by LBC. Poor correlations are more pronounced for the transient
parts than they are for the stationary parts of the fields. This is especially
true for the precipitation field, where differences can be attributed to higher
temporal variability during the summer due to the presence of
convection. 相似文献
47.
Takashi Tomiyasu Akito Matsuyama Ryusuke Imura Hitoshi Kodamatani Junko Miyamoto Yuriko Kono David Kocman Jo?e Kotnik Vesna Fajon Milena Horvat 《Environmental Earth Sciences》2012,65(4):1309-1322
Although the mining activity of the Idrija mine in Slovenia ceased in 1995, a large amount of mining dregs containing high
concentrations of mercury remains in the area. The mining dregs were transported with river flow and deposition along the
Idrija River. To estimate the dispersion and change in the chemical form of mercury, a total of 28 soil core samples were
taken around the river. The individual core samples were separated into layers for the analysis of their chemical composition,
carbon contents, total mercury (T-Hg) and methylmercury (MeHg) concentrations. The chemical composition measured by X-ray
fluorescence spectrometry was useful to estimate the dispersion of tailings: the fluvial terrace soil had a chemical composition
similar to that of the tailings and could be distinguished clearly from the forest soil. The highest T-Hg concentration, 1,100 mg kg−1, was observed in the fluvial terrace soil near the mine. Although the concentration decreased gradually along with distance
from the mine, concentrations higher than 200 mg kg−1 of T-Hg were still observed in the fluvial terrace soil approximately 20 km downstream from the mine. In the vertical distribution
of T-Hg in the hillslope soil, a higher value was observed in the upper layers, which suggests the recent atmospheric deposition
of mercury. The concentration of MeHg was the lowest at the riverside and higher in the hillslope soil, which was the opposite
of the T-Hg distribution. The total organic carbon content tracked similarly with the distribution of MeHg and a linear relation
with a significantly high correlation coefficient was obtained. The distinction may be related to the different dispersion
process of mercury, and the organic carbon contents may be an important factor for MeHg formation. 相似文献