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121.
Gorgonian species may contribute to the three-dimensional seascape in soft bottom-gravel areas, but the information on their
biology and ecology is very scarce. The biometry and secondary production of the Mediterranean soft bottom-gravel passive
suspension feeder Leptogorgia sarmentosa (Cnidaria: Octocorallia) was studied using photographic monitoring of the primary branches from May 1998 to September 2000.
The primary branches observed had a high density of polyps (2.2 ± 0.2 SD polyps mm−1) and a high organic matter content (63.2 ± 9.1 SD %). During the two-year sampling period, there was a net negative growth
in 90% of the gorgonian population. The mean loss during the 27-month period was −2.9 ± 0.9 SD cm per branch (5.7 mg C branch−1). However, considering only the initial and final diameters and maximum height in the 27 months elapsed time, the gorgonians
showed positive growth, which meant that photographic sampling of single branches was a more appropriate method for gorgonian
secondary production monitoring. A water mass anomaly detected in 1999 in the north-western Mediterranean Sea may have been
the cause of the net negative growth in L. sarmentosa in the studied area. Partial mortality due to different factors, such as strong currents, predation, disease, etc., could
be a common strategy in sessile colonial benthic populations that would facilitate their maintenance even during very stressful
circumstances. 相似文献
122.
123.
Octocorals are an important part of many ecosystems as they add three-dimensional complexity to the benthos and thereby increase biodiversity. The Mediterranean red coral (Corallium rubrum, L. 1758) is a longevous octocoral that is harvested commercially, yet natural and anthropogenic influences on its population size structure are little understood. This study found that some harvested red coral populations had a significantly different size structure when compared to populations at the nearby Marine Protected Area (MPA) of Medas Islands at the Spanish Costa Brava (NW Mediterranean). Eighty-nine percent of the red corals in the harvested Costa Brava area are less than 10 years old and 96% of all colonies have not yet grown more than second-order branches. The size/age distribution of the harvested population is notably skewed towards younger and smaller colonies. Thus, although red coral is still abundant, its population structure is strongly distorted by harvesting. The results confirm that MPAs are useful to distinguish between anthropogenic and natural influences on population structure. However, 14 years of protection appears to be an insufficient recovery time for a longevous octocoral population such as red coral. 相似文献
124.
E. Davoli E. Fattore V. Paiano A. Colombo M. Palmiotto A.N. Rossi M. Il Grande R. Fanelli 《Waste management (New York, N.Y.)》2010,30(8-9):1608-1613
An integrated risk assessment study has been performed in an area within 5 km from a landfill that accepts non hazardous waste. The risk assessment was based on measured emissions and maximum chronic population exposure, for both children and adults, to contaminated air, some foods and soil. The toxic effects assessed were limited to the main known carcinogenic compounds emitted from landfills coming both from landfill gas torch combustion (e.g., dioxins, furans and polycyclic aromatic hydrocarbons, PAHs) and from diffusive emissions (vinyl chloride monomer, VCM). Risk assessment has been performed both for carcinogenic and non-carcinogenic effects. Results indicate that cancer and non-cancer effects risk (hazard index, HI) are largely below the values accepted from the main international agencies (e.g., WHO, US EPA) and national legislation (D.Lgs. 152/2006 and D.Lgs. 4/2008). 相似文献
125.
Daniela Turchetti Elisabetta Razzaboni Hila Zomer Cesare Rossi Simona Ferrari Donatella Greco Claudio Graziano Giovanni Romeo Marco Seri 《黑龙江环境通报》2006,26(12):1156-1159
Angelman Syndrome (AS), characterized by mental retardation, absence of speech, seizures and motor dysfunction, is caused by genetic defects leading to loss of expression of the maternal copy of the chromosome 15q11–13 imprinted region. Most cases are sporadic, being caused by de novo deletion of maternal chromosome 15q11–13 (75%) or by paternal uniparental disomy (3–4%). Familial cases can occur, due to mutations in the UBE3A gene or in the imprinting center. We describe the case of a pregnant woman having two nephews with AS caused by a UBE3A mutation; lack of communication within the family led the woman to be completely unaware of the risk of disease recurrence until 15 weeks of gestation. UBE3A genetic testing revealed she carried the familial mutation 892–893delCT. Prenatal diagnosis was performed on amniotic fluid and demonstrated that the fetus had inherited the mutation. The unexpected diagnosis and the subsequent termination of the pregnancy caused the woman to undergo acute psychological distress showing relevant psychopathological symptoms. Nevertheless, at 2-year follow-up, adverse consequences were minimized, and the couple was planning a new pregnancy. Factors affecting the psychological outcome of abortion and the role of psychological support in reducing the risk of long-term unfavorable consequences are discussed. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
126.
Urban airborne particulate: genotoxicity evaluation of different size fractions by mutagenesis tests on microorganisms and comet assay 总被引:4,自引:0,他引:4
The genotoxic effects of different size fractions of airborne particulate (Total, PM10 and PM2.5), extracted with acetone or toluene, were evaluated by: the Ames plate test (TA98 and TA100 strains, w/o S9), gene conversion and reversion (w/o endogenous metabolic activation) in the Saccharomyces cerevisiae D7 strain, and the comet assay on human leukocytes. The data on human leukocytes confirm the sensitivity of the comet assay and its applicability to assess genotoxicity in environmental samples. The PM2.5 fraction of airborne particulate generally shows the highest concentration of DNA-damaging compounds. Genotoxic response, in all the test systems applied, is highly dependent on extraction solvent used. Acetone seems to extract compounds with more similar genotoxic responses in the three test systems used than toluene extracts. Toluene appears to extract air pollutants genotoxic on yeast and leukocytes but is mainly cytotoxic on Salmonella. 相似文献
127.
Bacteriophage transport through a fining-upwards sedimentary sequence: laboratory experiments and simulation 总被引:1,自引:0,他引:1
A column containing four concentric layers of progressively finer-grained glass beads (graded column) was used to study the transport of the bacteriophage T7 in water flowing parallel to layering through a fining-upwards (FU) sedimentary structure. By passing a pulse of T7, and a conservative solute tracer upwards through a column packed with a single bead size (uniform column), the capacity of each bead type to attenuate the bacteriophage was determined. Solute and bacteriophage responses were modelled using an analytical solution to the advection-dispersion equation, with first-order kinetic deposition simulating bacteriophage attenuation. Resulting deposition constants for different flow velocities indicated that filtration theory-determined values differed from experimentally determined values by less than 10%. In contrast, the responses of solute and bacteriophage tracers passing upwards through graded columns could not be reproduced with a single analytical solution. However, a flux-weighted summation of four one-dimensional advective-dispersive analytical terms approximated solute breakthrough curves. The prolonged tailing observed in the resulting curve resembled that typically generated from field-based tracer test data, reflecting the potential importance of textural heterogeneity in the transport of dissolved substances in groundwater. Moreover, bacteriophage deposition terms, determined from filtration theory, reproduced the T7 breakthrough curve once desorption and inactivation on grain surfaces were incorporated. To evaluate the effect of FU sequences on mass transport processes in more detail, bacteriophage passage through sequences resembling those sampled from a FU bed in a fluvioglacial gravel pit were carried out using an analogous approach to that employed in the laboratory. Both solute and bacteriophage breakthrough responses resembled those generated from field-based test data and in the graded column experiments. Comparisons with the results of simulations using averaged hydraulic conductivities show that simulations employing averaged parameters overestimate bacteriophage travel times and underestimate masses recovered and peak concentrations. 相似文献
128.
G. Duranti A. Rossi N. Rosato G. Fazio G. Sacerdoti P. Rossi R. Falsaperla V. Cannelli R. Supino 《The Environmentalist》2005,25(2-4):113-119
Summary The biological effects of electromagnetic radiation at ultra high frequency on human keratinocytes were investigated. HaCaT
cell system, a spontaneously immortalized human keratinocytes cell line, was chosen as model since skin is usually exposed
to electromagnetic radiation at considered frequency more than inner tissues. HaCaT cells were exposed to a pure sinusoidal
field at a frequency of 900 MHz (average SAR levels ranging from 0.04 to 0.08 W/kg) in plane wave condition inside a GTEM
chamber for time intervals of 18 hours at a controlled temperature of 37∘C. Growth curves were obtained for exposed and control cells, and a reduction in the number of exposed cells in comparison
to unexposed ones was found; however the number of dead cells was not significantly different in exposed and unexposed samples.
In order to investigate whether the reduction in cell proliferation of exposed cells was due to the activation of a differentiative
process, the expression of two hallmarks of differentiation was examined. Both keratin 1 and involucrin expression was increased
in exposed in comparison to unexposed cells. These results suggest that this protocol of exposure to 900 MHz electromagnetic
field can trigger a differentiation program in HaCaT cells. 相似文献
129.
Phylloscopus trochilus ), crossbills (Loxia spp.), and tree pipit (Anthus trivialis). The composition of the bird community did not vary significantly between the compared transects. Some species appeared
to favour road–forest edges but this could not be confirmed with our data. These species were not the same as have been reported
to favor clear-fellings–mature forest edges. Therefore, the edge effect does not seem to be the most important factor controlling
relative bird densities immediately adjacent and further away from highways. The likelihood of avoiding the problems the highways
are causing for bird density are been discussed. 相似文献
130.
L. Sola O. Cipelli E. Gornung A. R. Rossi F. Andaloro D. Crosetti 《Marine Biology》1997,128(4):573-577
A cytogenetic analysis by several staining techniques was carried out on specimens of Seriola dumerili from the Tyrrhenian coast of Sicily. The karyotype was found to be composed of 48 chromosomes in all the specimens examined.
All chromosomes are subtelo- and acrocentrics, except for one pair of small-sized submetacentric chromosomes. After Ag-staining,
nucleolus organizer regions (NORs) can be observed on the short arms of a medium-sized subtelocentric chromosome pair, and
after chromomycin A3-staining a bright fluorescent signal is evident at the same sites. The 18S rDNA mapping by fluorescence in situ hybridization
confirms this unique NOR location. The constitutive heterochromatin is mainly restricted to centromeres and the fluorochrome-staining
by chromomycin A3 and 4′,6-diamidino-2-phenylindole revealed a uniform base composition along the chromosomal arms; therefore stock/population-specific
marker chromosomes cannot be identified. Such cytogenetic features, however, rule out the presence of morphologically differentiated
sex-chromosomes in the greater amberjack.
Received: 16 January 1997 / Accepted: 31 January 1997 相似文献