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排序方式: 共有57条查询结果,搜索用时 31 毫秒
31.
A three-dimensional regression analysis attempted to model mesozooplankton (MSP) biomass using sea surface temperature (SST) and chlorophyll-a (Chl-a). The study was carried out from January 2014 to July 2015 in the southwestern Bay of Bengal (BoB) and sampling was carried out on board Sagar Manjusha and Sagar Purvi. SST ranged from 26.2 to 33.1 °C while Chl-a varied from 0.04 to 6.09 μg L?1. During the course of the study period, there was a weak correlation (r?= 0.32) between SST and Chl-a statistically. MSP biomass varied from 0.42 to 9.63 mg C m?3 and inversely related with SST. Two kinds of approaches were adopted to develop the model by grouping seasonal datasets (four seasonal algorithms) and comprising all datasets (one annual algorithm). Among the four functions used (linear, paraboloid, the Lorentzian and the Gaussian functions), paraboloid model was best suited. The best seasonal and annual algorithms were applied in the synchronous MODIS-derived SST and Chl-a data to estimate the MSP biomass in the southwestern BoB. The modelled MSP biomass was validated with field MSP biomass and the result was statistically significant, showing maximum regression coefficient for the seasonal algorithms (R2?=?0.60; p?=?0.627; α?= 0.05), than the annual algorithm (R2?=?0.52; p?=?0.015, α?=?0.05).  相似文献   
32.
Several studies have been using quantified consensus within climate science as an argument to foster climate policy. Recent efforts to communicate such scientific consensus attained a high public profile but it is doubtful if they can be regarded successful. We argue that repeated efforts to shore up the scientific consensus on minimalist claims such as “humans cause global warming” are distractions from more urgent matters of knowledge, values, policy framing and public engagement. Such efforts to force policy progress through communicating scientific consensus misunderstand the relationship between scientific knowledge, publics and policymakers. More important is to focus on genuinely controversial issues within climate policy debates where expertise might play a facilitating role. Mobilizing expertise in policy debates calls for judgment, context and attention to diversity, rather than deferring to formal quantifications of narrowly scientific claims.  相似文献   
33.
Journal of Material Cycles and Waste Management - The study deals with the management of deoiled rice bran by converting it into ethanol using a multi-enzyme preparation produced in-house...  相似文献   
34.
Samples of PM(2.5) were collected to measure the concentrations of its chemical constituents at two rural locations, Potsdam and Stockton, NY from November 2002 to August 2005. These samples were collected on multiple filters at both sites, every third day for a 24-h interval with a speciation network sampler. The Teflo(R) filters were analyzed for PM(2.5) mass by gravimetry, and elemental composition by X-ray fluorescence (XRF). Nylasorb(R) filters and Teflo(R) filters were leached with water and analyzed for anions and cations, respectively, by ion chromatography (IC). Fine particulate matter (PM(2.5)) mass and its inorganic component measurements were statistically characterized, and the temporal behavior of these species were assessed. Over the entire study period, PM(2.5) mass concentrations were lower at Potsdam (8.35 mug/m(3)) than at Stockton (10.24 mug/m(3)). At both locations, organic matter (OM) was the highest contributor to mass. Sulfate was the second highest contributor to mass at 27.0% at Potsdam, and 28.7% at Stockton. Nitrate contributions to mass of 8.9 and 9.5% at Potsdam and Stockton, respectively, were the third highest. At both locations, fine PM mass exhibited an annual cycle with a pronounced summer peak and indications of another peak during the winter, consistent with an overall increase in the rate of secondary aerosol formation during the summer, and increased partitioning of ammonium nitrate to the particle phase and condensation of other semi-volatiles during the winter, respectively. An ion-balance analysis indicated that at both locations, during the summers as well as in the winters, the aerosol was acidic. Lognormal frequency distribution fits to the measured mass concentrations on a seasonal basis indicated the overall increase in particle phase secondary aerosol (sulfate and SOA) concentrations during the summers compared to the winters at both locations.  相似文献   
35.
There is a growing concern over the potential accumulation of heavy metals in soils owing to rapid industrial and urban development and increasing reliance on agrochemicals in the last several decades. These metals can infiltrate through the soil thereby causing groundwater pollution. Surface soil samples (5 to 15 cm) collected from southeastern part of Ranga Reddy district were analyzed for 14 heavy metals (As, Ba, Co, Cr, Cu, Mo, Ni, Pb, Rb, Sr, V, Y, Zn and Zr) using Philips PW 2440 X-ray fluorescence spectrometer. Results for heavy and trace elements are reported for the first time in soils for this region. The contamination of the soils was assessed on the basis of enrichment factor (EF), geoaccumulation index (I (geo)), contamination factor and degree of contamination. The results reveal that variations in heavy element concentrations in the soil analyzed have both geogenic and anthropogenic contribution, due to the long period of constant human activities in the study area. The concentration of the metals Ba, Rb, Sr, V, Y and Zr were interpreted to be mainly inherited from parent materials (rocks) and the As, Co, Cr, Cu, Mo, Ni, Pb and Zn concentrations show contribution from geogenic and anthropogenic sources. The major element variations in soils are determined by the composition of the parent material predominantly involving granites.  相似文献   
36.
Environmental Chemistry Letters - The presence of recalcitrant organic pollutants in water is a major source of concern worldwide. These pollutants are not easily removed using conventional...  相似文献   
37.

This work describes the design of novel Cu(II) complexes and their application in the photocatalytic degradation of methylene blue (MB). The same photocatalyst exhibits antibacterial activity against Escherichia coli (gram-negative) and Bacillus circulans (gram-positive). The characterisation of the photocatalysts has been done by several up-to-date physical methods. The rationale behind the photocatalysts’ beneficial intervention is discussed in this study. Statistical analysis of the degradation of MB is done using a one-way ANOVA, and the significance of means is determined by a multiple comparison test using Turkey HSD. Also, the degradation of MB follows pseudo first-order kinetics with high correlation coefficient values (R2?>?0.95), making them useful as simple and low-cost organic dye degradation agents.

  相似文献   
38.
A comparative study (June-July 2001) on zooplankton community structure amid polluted conditions in a stagnant harbour and relatively unaffected tidal estuary near Visakhapatnam, on the east coast of India, revealed a marked disparity in species composition and abundance. While the harbour supported a rich population of calanoids (46.4%), the estuary sustained mostly cyclopoids (55.2%). Univariate and multivariate techniques (species diversity, clustering, non-metric multi-dimensional scaling and one-way ANOSIM) revealed the existence of two differing zooplankton assemblages and associated water quality (similarity 50.6%). While the estuary is typified by high amounts of dissolved silica (67.4 ± 17.7 μmol l-1) linked with monsoon influx, the harbour waters revealed abnormal levels of phosphate (40.9 ± 9.2 μmol l-1) and nitrate (15.3 ± 5.41 μmol l- 1) suggestive of intense eutrophication, caused by the discharge of fertilizer-factory waste and domestic sewage. On the basis of routines (e.g. BVSTEP, SIMPER) implemented in Plymouth Routines in Multivariate Ecological Research, it was possible to demonstrate that while species such as Oithona rigida, Oithona brevicornis, crustacean nauplii, gastropod veligers, Acartia spinicauda, and Acartia centrura played a key role in discriminating the zooplankton assemblage in the estuary, Acrocalanus spp. (mainly Acrocalanus gracilis) played a keyed role in harbour waters. Canonical Correspondence Analysis revealed species-environment relationships; for example, while the distribution of Oithona spp. and its associates in the estuary corresponded intimately with high silicate, temperature, and low salinity, it was high salinity, phosphate, and nitrate in the harbour channel that supported a different assemblage of copepods dominated by calanoids.  相似文献   
39.
40.
High natural radiation areas in the coastal and peninsular India were studied for airborne thorium and resultant population exposure due to inhalation. Four locations covering three states viz., Ayiramthengu and Neendakara in Kerala, Kudiraimozhi in Tamil Nadu and Bhimilipatnam in Andhra Pradesh were investigated. External gamma radiation fields 1 m above the monazite ore bodies ranged from 200 to 3000 nGy h-1. Soil samples showed 232Th specific activity varying from 0·1 to 1·5 Bq g-1 with surface alpha activity in the range of 1·0–12·5 Bq cm-2. Suspended particulates in the samples ranged from 60–140 μg m-3 with 232Th showing a wider variation of <0·03–0·3 mBq m-3. There was poor correlation between suspended particulates and long-lived alpha airborne activity . The resuspension factors for 232Th were in the range of 1·5×10-8–7·9×10-7 cm-1. Higher resuspension was correlated with dry sand dunes. The upper limits for Committed Effective Dose (CED) due to inhalation of airborne 232Th at the respective high natural radiation areas were estimated to range from 50±30 to 300±130 μSv (5–30 mrem) per year per adult member of public assuming an activity median aerodynamic diameter of 1 μm for the airborne particulates.  相似文献   
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