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141.
142.
Continental margins are important areas to be considered when studying the distributions and depositions of pollutants, both conventional and radioactive. Coastal sediments accumulate most of those contaminants which can be introduced following atmospheric and/or fluvial pathways. Moreover, their residence times within the water column are usually shortened due to their affinity to associate with the downward falling particulate matter, more abundant at shallower depths. In this paper the distribution profiles and inventories of plutonium, americium and cesium are detailed, providing useful information about recent sedimentation phenomena such as sediment mixing, slumping processes and bioturbation. Unsupported 210Pb data are used as reliable indicators of enhanced/reduced deposition events. Also, the calculated inventories have enabled the estimation of the radiological contribution of the Spanish Mediterranean margin to the total radioactivity deposited onto the Mediterranean sea floor. 相似文献
143.
Dias CM Santos RV Stenström K Nícoli IG Skog G da Silveira Corrêa R 《Journal of environmental radioactivity》2008,99(7):1095-1101
(14)C specific activities were measured in grass samples collected around Brazilian nuclear power reactors. The specific activity values varied between 227 and 299 Bq/kg C. Except for two samples which showed (14)C specific activities 22% above background values, half of the samples showed background specific activities, and the other half had a (14)C excess of 1-18%. The highest specific activities were found close to the nuclear power plants and along the main wind directions (NE and NNE). The activity values were found to decrease with increasing distance from the reactors. The unexpectedly high (14)C excess values found in two samples were related to the local topography, which favors (14)C accumulation and limits the dispersion of the plume. The results indicate a clear (14)C anthropogenic signal within 5 km around the nuclear power plants which is most prominent along northeastwards, the prevailing wind direction. 相似文献
144.
This study compares diversity and abundance of birds plus abundance of butterflies, bumblebees and herbaceous plants between six small farms (<52 ha arable land) and six large farms (>135 ha arable land) in Roslagen in southeastern Sweden. Two of the large and four of the small farms were organic. Large-scale landscape mosaic and underlying bedrock were similar for all farms. Statistical analysis was performed using box-plots on medians and analysis of variance on mean values. More than twice as many bird species and territories, butterflies, and herbaceous plant species, and five times more bumblebees were found on the small compared to the large farms. The largest differences were found between small organic and large conventional farms. Differences were also noted between small and large organic farms: 56% more bird species were found on small organic than on large organic farms, although none of the farms used any pesticides. We therefore argue that the consideration of organic agriculture's effect on biodiversity should include factors affected by farm size. 相似文献
145.
Professor Dr. med. Uwe Claussen Renate Ulmer Ernst Beinder Hans-Joachim Voigt 《黑龙江环境通报》1994,14(2):113-121
From September 1985 to March 1992, 804 amniotic fluid samples from 64 different diagnostic centres of the Federal Republic of Germany were sent to our laboratory exclusively for rapid karyotyping. The average time needed for notification of the analysed karyotype was 4·65 days when the ‘pipette method’ was used for chromosome harvesting and 5·97 days when the ‘in situ’ technique was used. The overall incidence of chromosome aberrations was 15·3 per cent. Data are presented about the likelihood of abnormal ultrasound findings being caused by chromosome aberrations. These findings include polyhydramnios, oligohydramnios, growth retardation, fetal effusions, neural tube defects, craniofacial defects, heart defects, gastroschisis and omphalocele, gastrointestinal tract defects, urinogenital defects, and limb defects. In future, such data need to contain larger numbers of cases for each week of gestation. This will improve the risk evaluation for each case with abnormal ultrasound findings, which should lead to better management during pregnancy, delivery, and postnatal care for those who require rapid karyotyping. 相似文献
146.
Review of Russian language studies on radionuclide behaviour in agricultural animals: part 2. Transfer to milk 总被引:2,自引:2,他引:0
Fesenko S Howard BJ Isamov N Voigt G Beresford NA Sanzharova N Barnett CL 《Journal of environmental radioactivity》2007,98(1-2):104-136
An overview of original information available from Russian language papers on radionuclide transfer to milk is provided. Most of the data presented have not been taken into account in international reviews. The transfer coefficient (F(m)) values for radioactive isotopes of strontium, caesium and iodine are in good agreement with those previously published. The Russian language data, often based on experiments with many animals, constitute a considerable increase to the available data for many less well-studied radionuclides. In some instances, the Russian language data suggest changes in recommended values (e.g. Zr and Ru). The information presented here substantially increases the amount of available data on radionuclide transfer to milk and will be included in the current revision of the IAEA TRS Handbook of parameter values for radionuclide transfer. 相似文献
147.
Christoph J. Hellig Michaela Kerschbaumer Kristina M. Sefc Stephan Koblmüller 《Die Naturwissenschaften》2010,97(7):663-672
The morphological versatility of the pharyngeal jaw of cichlid fishes is assumed to represent a key factor facilitating their
unparalleled trophic diversification and explosive radiation. It is generally believed that the functional design of an organism
relates to its ecology, and thus, specializations to different diets are typically associated with distinct morphological
designs, especially manifested in the cichlids’ pharyngeal jaw apparatus. Thereby, the lower pharyngeal jaw (LPJ) incorporates
some of the most predictive features for distinct diet-related morphotypes. Thus, considering that piscivorous cichlids experience
an ontogenetic dietary shift from typically various kinds of invertebrates to fish, concomitant morphological changes in the
LPJ are expected. Using Lepidiolamprologus elongatus, a top predator in the shallow rocky habitat of Lake Tanganyika, as model, and applying geometric and traditional morphometric
techniques, we demonstrate an allometric change in ontogenetic LPJ shape development coinciding with the completion of the
dietary shift toward piscivory. The piscivorous LPJ morphotype is initiated in juvenile fish by increasing elongation and
narrowing of the LPJ and—when the fish reach a size of 80–90 mm standard length—further refined by the elongation of the posterior
muscular processes, which serve as insertion for the fourth musculus levator externus. The enlarged muscular processes of
the fully mature piscivorous morphotype provide for the construction of a powerful lever system, which allows the large individuals
to process large prey fish and rely on exclusive piscivory. 相似文献
148.
Tina Mesarič Kristina Sepčič Veronica Piazza Chiara Gambardella Francesca Garaventa Damjana Drobne 《Chemistry and Ecology》2013,29(7):643-652
The effects of two carbon-based nanomaterials, nano-sized carbon black (nCB), and single-layer graphene oxide (GO) on settlement of Amphibalanus amphitrite (Cirripedia, Crustacea) cypris larvae (cyprids) were assessed after 24, 48, and 72 h of exposure. Additionally, the effects of these nanomaterials on the mortality and swimming behaviour of the nauplius larvae (nauplii) of the same organism were determined after 24 and 48 h. The data indicate that nCB is more effective as a potential antisettlement agent than single-layer GO; moreover, nCB did not show any adverse effects on the larvae. The swimming behaviour of II stage nauplii of A. amphitrite exposed to a suspension of nCB was inhibited only at very high nCB concentrations (≥0.5 mg/mL). Single-layer GO, on the contrary, showed lower antisettlement effects and was more active in altering the survival and inhibiting the swimming behaviour of the nauplii. An indication of the toxic or non-toxic mechanisms of the antisettlement properties of both of these nanomaterials is provided by the reversibility of the antisettlement activity. In conclusion, we propose nCB as an innovative antifouling nanomaterial that shows low toxicity towards the model organism (crustaceans) used in this study. 相似文献
149.
DuBose B. Griffin Sally R. Murphy Michael G. Frick Annette C. Broderick John W. Coker Michael S. Coyne Mark G. Dodd Matthew H. Godfrey Brendan J. Godley Lucy A. Hawkes Thomas M. Murphy Kristina L. Williams Matthew J. Witt 《Marine Biology》2013,160(12):3071-3086
From 1998 to 2008, 68 adult female loggerhead sea turtles (Caretta caretta) were instrumented with platform transmitter terminals at nesting beaches in Georgia, North Carolina (NC) and South Carolina (SC) on the East Coast of the United States of America (30°48′N, 81°28′W to 33°51′N, 77°59′W). The majority of post-nesting loggerheads (N = 42, 62 %) migrated to foraging habitats in the Mid-Atlantic Bight during May–October, with a subsequent migration occurring during November–March to foraging habitats south of Cape Hatteras, NC. Nine (13 %) loggerheads initially foraged in the near-shore, coastal areas of the South Atlantic Bight, but moved to offshore habitats—closer to the Gulf Stream—during November–March, while fourteen (21 %) loggerheads remained in foraging areas along the mid-continental shelf off of the eastern coast of Florida and/or continued southward to Florida Bay and the Bahamas. The present study delineates important, post-nesting foraging habitats and migration corridors where loggerheads may interact with commercial fisheries—providing managers opportunities to develop and implement optimally effective conservation actions for the recovery of this threatened species. 相似文献
150.
Sahin UA Scherbakova K Onat B 《Environmental science and pollution research international》2012,19(4):1198-1209