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1.
Otoliths of juvenile silver perch were marked by immersing live fish for 3 h in a calcein-seawater solution. Calcein produced a fluorescent mark on the sagittal otoliths that was visible under ultraviolet light. The hypothesis of one increment per day was tested by regressing the number of otolith increments that formed after marking on the number of days that fish were held in lab and field experiments. Silver perch formed one increment per day under nearly all conditions. Salinity (15‰ or 30‰) and dietary ration (4% or 10% body weight d?1) were varied among experimental groups of lab-reared fish. The short-term effect of low rations appears primarily as interrupted formation of otolith increments: fish fed 10% body weight d?1 formed one increment per day but fish fed 4% d?1 averaged less than one increment d?1. Reduction in increment formation occurred despite no significant difference in average width of otolith increments or apparent condition of silver perch over the 20-d experiment. Salinity effects were difficult to interpret: salinity interacted with ration to modify increment formation but did not independently alter the daily rate of increment formation. This novel interaction among ration and salinity is not well understood and warrants additional study. In silver perch, otolith growth appears responsive and sensitive to local environmental conditions. This responsiveness confirms the need for validation of increment formation across the range of environmental conditions that fish are likely to encounter. It also suggests that otolith structure may contain detailed information about the life history of individual silver perch. 相似文献
2.
Juvenile spot,Leiostomus xanthurus (Pisces), were collected at 2-h intervals over two 48-h periods in a tidal creek in North Inlet, South Carolina, during July 1986. Gut fullness, dry gut contents weight as a percentage of fish wet weight, was measured to test the hypothesis that feeding intensity is randomly distributed through time. Spot were also collected and serially sacrificed from a holding tank to estimate their gut evacuation rate. Gut fullness was greatest during periods of ebb and high tides and was little affected by the amount of light available. Gut contents were evacuated at a rate of about 15% per hour in the laboratory, in close agreement with field emptying times of about 6 h from peak fullness to empty guts. A conservative estimate of daily ration for juvenile spot (19–42 mm standard length) was 4.5% of their live body weight per day. Studies of spot feeding ecology can be greatly affected by when fish are collected during the tidal cycle. 相似文献
3.
Nineteen species of Diptera (16 in each zone) from seven families were found in monthly collections (June 1979 through May 1980) in two Mississippi marsh plant zones dominated byJuncus roemerianus Scheele andSpartina cynosuroides (L.) Roth, respectively. TheJuncus zone was dominated by a species ofPalpomyia-Bezzia complex, two species ofBezzia (Ceratopogonidae),Paratendipes sp.,Limnophyes sp. (Chironomidae) andThinophilus frontalis (Dolichopodidae).Palpomyia-Bezzia sp.,Culicoides hollensis, Ormosia sp. (Tipulidae) andPelastoneurus abbreviatus (Dolichopodidae) dominated theSpartina zone. Total inset density and species richness were lowest in June and July in both zones, corresponding to a pulse of adult emergence. Overall, total density was significantly higher in theSpartina zone with mean values of 165 and 245 insects m?2 for the {Juncus} and {Spartina} zones, respectively. In addition to total density, differences in abundance were apparent for a number of species between marsh zones. Patterns could be attributed to species-specific habitat preference., predation by aquatic predators, and/or by interactions of the infauna themselves. 相似文献
4.
The last major eruption of La Soufrière volcano in Guadeloupe (Lesser Antilles) in 1976–1977 caused the mass evacuation of part of the population, whereby a total of 76,000 people were displaced for a period of 3–6 months. This evacuation has left a bitter memory among the inhabitants who believed that the political authorities of the time had not anticipated the possibility of an eruption crisis and that decisions were taken in haste. La Soufrière remains active, and future eruptions could once again lead to partial or even total evacuation of the population if there were a major Plinian eruption. This article offers an investigation of future evacuation procedures, questioning different aspects of Guadeloupe’s current territorial and social challenges (the multi-risk context, the reporting to the scientists and to the authorities, the importance of local solidarity). In order to do so, we used the Focus Group Discussion method, making it possible to identify resources and gaps in crisis management on the basis of previous event history. 相似文献
5.
B. Marler 《Physics and Chemistry of Minerals》1988,16(3):286-290
Five different refraction formulas were applied to SiO2 polymorphs in order to determine the most suitable refractive index-density relation. 13 SiO2 polymorphs with topological different tetrahedral frameworks are used in this study including eight new low density SiO2 polymorphs — so called “guest free porosils”. These SiO2 polymorphs cover a density range from 1.76 to 2.92 g/cm3. The mean refractive indices (ovn) of the porosils have been determined by the immersion method, the densities (ρ) were calculated from the unit cell parameters. Assuming the polarizability (α) of all SiO2 polymorphs to be constant the general refractivity formula $$\{ 2\overline {11} 0\} \langle 0001\rangle $$ turned out to be the most suitable for SiO2 polymorphs. Regression analysis yields an electronic overlap parameter b=1.2(1). 相似文献
6.
The paper presents the nature of variations of tropospheric and total ozone column retrieved from the Convective Cloud Differential (CCD) technique, Ozone Monitoring Instrument (OMI), and Total Ozone Mapping Spectrometer (TOMS) data, National Aeronautics and Space Administrations (NASA), USA, respectively; surface temperature, relative humidity, total rainfall, ozone precursors (non-methane hydrocarbon, carbon monoxide, nitrogen dioxide, and sulphur dioxide) that are collected from India Meteorological Department (IMD), Alipore, Kolkata; solar insolation obtained from Solar Geophysical Data Book and El-Niño index collected from National Climatic Data Center, US Department of Commerce, National Oceanic and Atmospheric Administration, USA. The effect of these climatic parameters and ozone precursors on ozone variations is critically analyzed and explained on the basis of linear regression and correlation. It has been observed that the maximum, minimum and mean temperature, relative humidity, solar insolation, tropospheric, and total ozone column (TOC) showed slight increasing tendencies from October 2004 to December 2011, while total rainfall and El-Niño index showed little decreasing tendencies for the same period. Amongst selected climatic parameters and ozone precursors, the solar insolation and the average temperature had a significant influence on both, the tropospheric ozone and total ozone column formation. The solar insolation had contributed more in tropospheric ozone than in total ozone column; while El-Niño index had played a more significant role in total ozone column build up than in tropospheric ozone. Negative correlation was observed between almost all ozone precursors with the tropospheric and total ozone. The tropospheric ozone and total ozone column were also significantly correlated. The level of significance and contribution of different climatic parameters are determined from correlation technique and Multiple Linear Regression (MLR) method. The related chemical kinetics for ozone production processes has been critically described. 相似文献
7.
Maunu Härme 《Contributions to Mineralogy and Petrology》1966,12(1):13-14
Recentlyvon Platen applied the results of his laboratory experiments to a migmatite studied byHärme. Some comments are presented upon that re-interpretation. 相似文献
8.
A comprehensive seismic risk assessment has been performed for the existing route of the 3rd Azerbaijan natural gas buried pipeline in Iran. The major active seismic sources along the pipeline were identified and the geometrical parameters as well as the seismicity rates were determined. The seismic hazard assessment of the ground vibrations along the pipeline was performed in the framework of the Probabilistic Seismic Hazard Analysis using the CRISIS 2007 software. All of the components of the gas pipeline along the route were identified and the corresponding fragility functions are established through the methodology described in the HAZUS guideline (HAZUS MH MR4 Technical manual 2007 Department of homeland security emergency. Preparedness and Response Directorate, FEMA). A detailed cost analyses was taken into consideration based on the expert opinions in the National Iranian Gas Company, in order to provide more practical loss model for the pipeline route. Also, a simple method is suggested in order to account for the vent gas in the total loss estimation. The spatial analysis of the hazard function layer in combination with the loss model layer, in Geographical Information System (GIS) platform, reveal the financial consequences of different earthquake scenarios. 相似文献
9.
We implement a hierarchical Bayesian spatiotemporal (HBST) model to forecast the daily trapped particle flux distribution over the South Atlantic Anomaly (SAA) region. The National Oceanic and Atmospheric Administration (NOAA)-15 data from 1–30 March 2008 with particle energies as >30 keV (mep0e1) and >300 keV (mep0e3) for electrons and 80–240 keV (mep0p2) and > 6900 keV (mep0p6) for protons were used as the model input to forecast the flux values on 31 March 2008. Data were transformed into logarithmic values and gridded in a 5°×5° longitude and latitude size to fulfill the modelling precondition. A Monte Carlo Markov chain (MCMC) was then performed to solve the HBST Gaussian Process (GP) model by using the Gibbs sampling method. The result for this model was interpolated by a Kriging technique to achieve the whole distribution figure over the SAA region. Statistical results of the root mean square error (RMSE), mean absolute percentage error (MAPE), and bias (BIAS) showed a good indicator of the HBST method. The statistical validation also indicated the high variability of particle flux values in the SAA core area. The visual validation showed a powerful combination of HBST-GP model with Kriging interpolation technique. The Kriging also produced a good quality of the distribution map of particle flux over the SAA region as indicated by its small variance value. This suggests that the model can be applied in the development of a Low Earth Orbit (LEO)-Equatorial satellite for monitoring trapped particle radiation hazard. 相似文献
10.
On formation of a bed and distribution of bed thickness, A. N. Kolmogorov presented a mathematical explanation that if repetitive alternations of material accumulation and erosion form a sequence of beds, the resultant bed-thickness distribution curve takes a shape truncated by the ordinate at zero thickness. In this truncated distribution curve, its continuation and extension from positive to negative thickness represents the distribution of beds with negative thickness, that is, the depth of erosion. When a distribution curve, including both positive and negative parts, is expressed by a function f(x),the ratio \(\int_0^\infty {f(x)dx to} \int_{ - \infty }^\infty {f(x)dx} \) ,called Kolmogorov's coefficient and designated as p,is a parameter representing the degree of accumulation in the depositional environment. On the assumption that f(x)is described by the Gaussian distribution function, the coefficient pfor Permian and Pliocene sequences in central Japan was calculated. The coefficients also were obtained from published data for different types of sediments from other areas. It was determined that they are more or less different depending on their depositional environments. The calculated results are summarized as follows: $$\begin{gathered} p = 0.80 - 1.0for{\text{ }}alluvial{\text{ }}or{\text{ }}fluvial{\text{ }}deposits \hfill \\ p = 0.65 - 0.95for{\text{ }}nearshore{\text{ }}sediments \hfill \\ p = 0.55 - 0.95for{\text{ }}geosynclinal{\text{ }}sediments \hfill \\ p = 0.90 - 1.0for{\text{ }}varves \hfill \\ \end{gathered} $$ In addition, a ratio \(q = \int_0^\infty {xf(x)dx/} \int_{ - \infty }^\infty {|x|f(x)dx} \) ,called Kolmogorov's ratio in this paper, is introduced for estimating a degree of total thickness actually observed in the field relative to total thickness once present in a basin. The calculated results of Kolmogorov's ratio are as follows: $$\begin{gathered} q = 0.88 - 1.0for{\text{ }}alluvial{\text{ }}or{\text{ }}fluvial{\text{ }}deposits \hfill \\ q = 0.68 - 0.98for{\text{ }}nearshore{\text{ }}sediments \hfill \\ q = 0.55 - 0.96for{\text{ }}geosynclinal{\text{ }}sediments \hfill \\ q = 0.92 - 1.0for{\text{ }}varves \hfill \\ \end{gathered} $$ The sedimentological significance of these values is discussed. 相似文献
11.
The sensitivity of the blueback herringAlosa aestivalis to acidity and aluminum (AI) in reconstituted, soft freshwater (23–25 mg I?1 hardness as CaCO3) was investigated in a continuous exposure laboratory study. Mature (20–24 h postfertilization) embryos were more tolerant than 1- to 5-day-old yolk-sac larvae. Significant mortality of embryos occurred only when pH was 5.0 and the total Al concentration was 0.42 mg I?1 (predicted MIBK-extracted total monomeric AI=0.34 mgI?1). Moderate acidity dramatically decreased the survival of yolksac larvae. Mean mortality was 99% in pH 5.0 and 89% in pH 5.7 compared to 38% in pH 6.5 and 16% in pH 7.8 without AI. The toxicity of AI to yolk-sac larvae was pH- and dose-dependent. Total AI concentrations up to 0.34 mg l?1 (predicted total monomeric AI up to 0.21 mg l?1) were not toxic at pH 6.5 and 7.8. At pH 5.0 and 5.7, AI increased the rate at which yolk-sac larvae died during a 96-h exposure (i.e., time to 50% mortality decreased with increasing AI). Continuous exposure to a predicted total monomeric AI level of only 0.03 mg I?1 at pH 5.0 killed all yolk-sac larvae in <24 hours. The mechanisms of acid and AI toxicity were apparently physiological and not associated with extensive cellular damage. Acidification events measured in Chesapeake Bay tributaries may reduce survival of blueback herring yolk-sac larvae and embryos exposed to those events. 相似文献
12.
Over recent years, the prevalence of the West Nile virus (WNV) in Canada has greatly increased due to various factors including changes in feeding behavior among WNV vectors. To understand whether changes in climate are a significant factor, the association between the environment and cases of WNV-infected bird specimens from 2009 to 2012 in Ontario, Canada, was examined using SAS and Quantum Geographic Information Systems (QGIS). Through a generalized linear mixed analysis, monthly totals of cooling degree days (CDD) and a two-way interaction between maximum temperature (Tmax) and precipitation were significantly positively associated to past incidences of WNV; while Tmax, precipitation, and a two-way interaction between CDD and precipitation were significantly negatively associated to past incidences of WNV. With the effects of increased warming, locations at higher latitudes in Canada may soon be at risk to WNV, as a positive case of WNV in a bird specimen was found close to the near north of Ontario in 2012. 相似文献
13.
Sources and history of PAHs in lake sediments from oil-producing and industrial areas,northeast China 总被引：1，自引：0，他引：1
L. Sun S. Y. Zang H. J. Sun 《International Journal of Environmental Science and Technology》2014,11(7):2051-2060
Abundance, sources, and historical records of polycyclic aromatic hydrocarbons (PAHs) in sediment cores of three lakes located in northeast China were evaluated. One lake was located in a rural oil field area, one in an industrial urban oil field area, and the third in an urban industrialized area without oil field influence. Cores from each lake were divided into 1-cm sections, dated using 137Cs techniques, and 16 priority PAH compounds were measured. Total PAH concentrations were greater in industrial areas than in rural area, regardless of associated oil production. Only petroleum sources of PAHs were identified in lakes near oil fields between 1950s and 1980s, while sources of liquid fossil fuel combustion were persistently identified in the industrial urban lake. From 1990s to 2000s, PAH concentrations, especially high molecular weight PAHs, significantly increased in all lakes, which were consistent with the economic development in China, suggesting a change in energy use from wood burning and petroleum (oil) to liquid fossil fuel combustion. Environmental risk was low to moderate in sediments of the three lakes studied, and increases in high molecular weight PAHs during 1900s–2000s is a concern. 相似文献
14.
C. A. Angell C. A. Scamehorn C. C. Phifer R. R. Kaiyala P. A. Cheeseman 《Physics and Chemistry of Minerals》1988,15(3):221-227
We give a brief review of ion dynamics studies of liquid and glassy states of SiO2 and silicate colutions which have been carried out in recent years in this laboratory. We summarize studies on SiO2, Na+ migration in Na2O·SiO2 in the “glassy state”, and ionic coordination in multicomponent framework silicates. We present new results on the coordination of Al3+ in albite as a function of pressure and show that it is consistent with results of laboratory studies on albite glasses formed at high pressure. We compare calculated PVT data for jadeite, albite and diopside and relate the behavior of the low pressure compressibility to the spinodal limit at negative pressures. Some preliminary studies of inert gas solution in jadeite and of CO2 solution in a glass having a composition of approximately Na2O·3SiO2 are described. 相似文献
15.
Andrew Robertson Bernard W. Gottholm Donna D. Turgeon Douglas A. Wolfe 《Estuaries and Coasts》1991,14(3):290-298
This paper uses results from the National Oceanic and Atmospheric Administration’s National Status and Trends Program (NS&T) to place the environmental quality of Long Island Sound in a broader perspective. It compares levels of contaminants in blue mussels from ten Long Island Sound sites and in sediments from seven Long Island Sound sites with concentrations in the same media at 87 and 221 other sites, respectively, where comparable samples were obtained. In sediments, the levels of both trace metals and organic contaminants tend to be relatively high for Long Island Sound sites. This is especially true for five of the twelve metals (silver, cadmium, copper, lead, and zinc) and for five of six categories of organic contaminants (total chlordane, low molecular weight polycyclic aromatic hydrocarbons (PAHs), high molecular weight PAHs, total polychlorinated biphenyls, and total dichlorodiphenyltrichloroethanes). In mussels, the organic contaminant categories exhibit relatively high levels, but this is not true for most of the metals. In fact, four of the metals—arsenic, mercury, selenium, and zinc—show evidence of relatively low levels in mussels from Long Island Sound compared to other NS&T locations. 相似文献
16.
17.
Howard W. Harder Eric C. Christensen Janis R. Matthews Terry F. Bidleman 《Estuaries and Coasts》1980,3(2):142-147
Toxaphene concentrations in rainfall over a South Carolina salt marsh were monitored from 1976–1978. This insecticide is toxic to some organisms in the low μg/kg range and causes sublethal effects in the very low ng/kg range. Rainfall was sampled by both continuously exposed collectors and by collectors which were exposed only during actual precipitation. Toxaphene concentrations in individual rainstorms showed a high day-to-day variation, and in general were 10–100 times higher than PCB and DDT levels. Washout ratios for toxaphene were higher than those reported for other chlorinated hydrocarbons, but lower than those of trace metals. During and immediately following the summer use season, toxaphene levels in rain exceeded by several times those concentrations reported to produce bone damage to young fish in laboratory experiments. The estimated aerial input of toxaphene to the 26 km2 estuary was 1.2 kg over a 4-month period. Most of this input appeared to be due to rainfall rather than dry deposition. *** DIRECT SUPPORT *** A01BY010 00007 相似文献
18.
D. K. Verma S. H. Hasan D. Ranjan R. M. Banik 《International Journal of Environmental Science and Technology》2014,11(7):1927-1938
Phanerochaete chrysosporium, a white rot basidiomycete, was immobilized over Luffa cylindrica sponge discs, treated with 0.1 N HCl and its potentiality for the removal of hexavalent chromium [Cr(VI)] from water was investigated in both batch and in up-flow fixed-bed bioreactor. The acid treatment of biomass increased the uptake capacity and percentage removal of Cr(VI) from 33.5 to 46.5 mg g?1 and 67 to 92 %, respectively. Maximum uptake of Cr(VI) was achieved at pH 2, temperature 40 °C after 100 min of contact time. The Cr(VI) sorption on the biomass was better explained by Langmuir isotherm. Thermodynamic studies indicated that the process was spontaneous and endothermic. Sorption kinetic study showed that pseudo-second-order model best correlates the Cr(VI) sorption on the biomass as compare to pseudo-first-order kinetic model. The performance of fixed-bed bioreactor was evaluated at different bed heights (5, 15 and 25 cm) and flow rates (1.66, 4.98 and 8.33 mL min?1) by using bed depth service time model. Response surface methodology statistical method was applied for optimizing the process parameters. FTIR analysis showed that amino groups were mainly involved in adsorption of Cr(VI). 相似文献
19.
Bank slope stability has become a great concern, while the impoundment of Three Gorges reservoir. The bank slope composed of red-layer soft rock has exhibited distinct deformation and failure. Therefore, a typical red-layer soft rock around Three Gorges reservoir area was selected to demonstrate the process of cyclic changes at the reservoir level and immersion-air-dry cyclic action of water-rock inside hydro-fluctuation belt. To meet the objective of this study, a series of creep tests were conducted on the rock specimens at different water-rock interaction stages. The following points were noticed based on the laboratory results: (1) the creep fracture strength and long-term strength of red-layer soft rock degraded significantly during the process of water-rock interaction. For the first three water-rock interaction circulations, the strength of red-layer soft rock degraded quickly and then gradually became stable. (2) During the creep test, the lateral expansion of red-layer soft rock increased significantly regarding to the number of cycles. (3) The creep curve includes three typical stages at failure stress level—primary (damped) stage, secondary (steady-state) stage, and tertiary (nonlinear accelerated) stage. As the number of cycles increased, the percentage of secondary stage diminished gradually. However, the tertiary stage showed a gradual increment, since the plasticity of the specimens was strengthened by water-rock interaction. (4) The shear failure characteristics of the specimens became highly considerable during the process of water-rock interaction, and there have been a gradual increment of shear rupture zone. (5) The SEM results showed that the specimen microstructure changed its state from dense to loose and porous. The findings of this research provide a good basis for long-term stability analysis of bank slope. 相似文献
20.
Medium-to high-pressure granulite facies complexes represent samples of lower crustal material and are, therefore, important in the study of crustal processes. New rare earth element data for the Scourian granulite facies terrain of the Precambrian Lewisian complex of N.W. Scotland indicate that:
- Overall, the Scourian complex has a light rare earth enriched pattern with a small but distinct positive Eu anomaly;
- While some rare earth element trends for the complex as a whole (e.g., Σ REE vs SiO2) are similar to those observed in upper crustal cogenetic sequences, others (e.g., Eu/Eu* vs SiO2) are reversed;
- Compared to average upper crust, the Scourian complex is depleted in REE (except Eu) by a factor of 2 to 3.