The chemical characterization of the thermal waters in Budapest,Hungary by using multivariate exploratory techniques     

Judit Déri-Takács  Anita Erőss  József Kovács 《Environmental Earth Sciences》2015,74(12):7475-7486

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Biosorption of heavy metals by a marine bacterium   总被引：1，自引：0，他引：1  

Iyer A  Mody K  Jha B 《Marine pollution bulletin》2005,50(3):340-343

Heavy metal chelation property of exopolysaccharide produced by Enterobacter cloaceae, a marine bacterium, isolated from the West Coast of India, is reported in this paper. The exopolysaccharide demonstrated excellent chelating properties with respect to cadmium (65%) followed by copper (20%) and cobalt (8%) at 100 mg/l heavy metal concentration. However, it could not chelate mercury. A comparative study of the percentage biosorption of the above mentioned metals is presented here.  相似文献   

Bianchi Type-III stiff fluid cosmological model in general relativity     

Anita Bagora 《Astrophysics and Space Science》2009,319(2-4):155-159

In this paper, we have investigated a tilted Bianchi Type-III stiff fluid cosmological model in general relativity. To get a determinate solution, we have assumed a condition A=(BC) ⁿ between metric potentials. The various physical and geometrical aspects of the model are discussed.  相似文献   

Spatial geochemistry of a Carboniferous platform-margin-to-basin transect: Balancing environmental and diagenetic factors   总被引：1，自引：0，他引：1  

Bram van der Kooij  Adrian Immenhauser  Anita Csoma  Juan Bahamonde  Thomas Steuber   《Sedimentary Geology》2009,219(1-4):136-150

Conventional (one-dimensional) chemostratigraphy of marine carbonates assesses the chemical archive of individual stratigraphic sections and their correlation in space and time. Whereas this approach has shown to be of value when linking isobathymetric domains, usually characterised by similar facies, more caution is needed when correlations are extended across different physiographic settings and hence different facies belts. Here, the spatial geochemical record of Pennsylvanian platform-margin-to-basin transects across a bathymetric range of about 800 m is documented and discussed in a process-oriented context. Particularly, the presence of layered palaeo-water masses and their potential control on slope facies distribution and geochemical properties requires attention. Whereas Carboniferous thermo- and/or chemo-clines most likely affected depth-related slope facies zonation, it was facies change and hence, variances in porosity–permeability properties, that controlled differential early burial diagenetic alteration. Specifically, the lower-slope related breccia facies is characterised by higher volumes of early burial carbonate cements. This implies that these sediments entered the shallow-burial domain with a considerable open pore space and gave way to an increased rock:fluid ratio. Whereas the δ¹³C record is invariant with bathymetry, the more diagenesis-sensitive δ¹⁸O proxy, records pronounced shifts observed across major facies boundaries. From this it is concluded that although the primary controlling factor of slope facies distribution with depth is probably palaeoceanographic in nature, it is differential rock:fluid ratios that control the first-order, spatial shifts in δ¹⁸O composition. These findings show that one-dimensional chemostratigraphy will severely underestimate the complexity of three-dimensional (bathymetric) data sets across platform margins. This is of relevance for the interpretation of the geochemical archive of fossil carbonate platforms in general.  相似文献   

Isolation,biodegradation ability and molecular detection of hydrocarbon degrading bacteria in petroleum samples from a Brazilian offshore basin     

Suzan Pantaroto de Vasconcellos  Elaine Crespim  Georgiana Feitosa da Cruz  Diego Barbosa Senatore  Karen Christina Marques Simioni  Eugênio Vaz dos Santos Neto  Anita Jocelyne Marsaioli  Valéria Maia de Oliveira 《Organic Geochemistry》2009,40(5):574-588

The detection of microorganisms with potential for biodeterioration and biodegradation in petroleum fields is of great relevance, since these organisms may be related to a decrease in petroleum quality in the reservoirs or damage in the production facilities. In this sense, petroleum formation water and oil samples were collected from the Campos Basin, Brazil, with the aim of isolating microorganisms and evaluating their ability to degrade distinct classes of hydrocarbon biomarkers (9,10-dihydrophenanthrene, phytane, nonadecanoic acid and 5α-cholestane). Twenty eight bacterial isolates were recovered and identified by sequencing their 16S rRNA genes. Biodegradation assays revealed that bacterial metabolism of hydrocarbons occurred through reactions based on oxidation, carbon–carbon bond cleavage and generation of new bonds or by the physical incorporation of hydrocarbons into microbial cell walls. Based on the biodegradation results, selective PCR-based systems were developed for direct detection in petroleum samples of bacterial groups of interest, namely Bacillus spp., Micrococcus spp., Achromobacter xylosoxidans, Dietzia spp. and Bacillus pumilus. Primer sets targeting 16S rRNA genes were designed and their specificity was confirmed in silico (i.e. computational analysis) and in PCR reactions using DNA from reference strains as positive and negative controls. Total DNA from oil was purified and the amplification tests revealed the presence of the target bacteria in the samples, unraveling a significant potential for petroleum deterioration in the reservoirs sampled, once proper conditions are present for hydrocarbon degradation. The application of molecular methods for rapid detection of specific microorganisms in environmental samples would be valuable as a supporting tool for the evaluation of oil quality in production reservoirs.  相似文献   

Correction to: Trace ambient levels of particulate mercury and its sources at a rural site near Delhi     

Anita Kumari  Umesh Kulshrestha 《Journal of Atmospheric Chemistry》2018,75(4):357-357

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Divergent trends in ecosystem services under different climate-management futures in a fire-prone forest landscape     

Joshua S. Halofsky  Jessica E. Halofsky  Miles A. Hemstrom  Anita T. Morzillo  Xiaoping Zhou  Daniel C. Donato 《Climatic change》2017,142(1-2):83-95

While ecosystem services and climate change are often examined independently, quantitative assessments integrating these fields are needed to inform future land management decisions. Using climate-informed state-and-transition simulations, we examined projected trends and tradeoffs for a suite of ecosystem services under four climate change scenarios and two management scenarios (active management emphasizing fuel treatments and no management other than fire suppression) in a fire-prone landscape of dry and moist mixed-conifer forests in central Oregon, USA. Focal ecosystem services included fire potential (regulating service), timber volume (provisioning service), and potential wildlife habitat (supporting service). Projections without climate change suggested active management in dry mixed-conifer forests would create more open forest structures, reduce crown fire potential, and maintain timber stocks, while in moist mixed-conifer forests, active management would reduce crown fire potential but at the expense of timber stocks. When climate change was considered, however, trends in most ecosystem services changed substantially, with large increases in wildfire area predominating broad-scale trends in outputs, regardless of management approach (e.g., strong declines in timber stocks and habitat for closed-forest wildlife species). Active management still had an influence under a changing climate, but as a moderator of the strong climate-driven trends rather than being a principal driver of ecosystem service outputs. These results suggest projections of future ecosystem services that do not consider climate change may result in unrealistic expectations of benefits.  相似文献   

Density and temperature diagnostics of solar emission lines from NeV/MgV and SiVII/MgVII Ions     

Anita Mohan  B. N. Dwivedi  P. K. Raju 《Journal of Astrophysics and Astronomy》1999,20(1-2):51-65

We present NeV/MgV and SiVII/MgVII theoretical line intensity ratios as a function of electron densityN _e and temperatureT _e . These are shown in the form of ratio-ratio diagrams, which should in principle allow bothN _e andT _e to be deduced for the emitting region of the solar plasma. We apply these diagnostics in the solar atmosphere, and discuss the available observations made from space. In most cases, however, we deduceN _e andT _e from the computed absolute line intensities in a spherically symmetric model atmosphere of the Sun. Possible future applications of this investigation to spectral data from the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO) are briefly discussed.  相似文献   

Enrichment of basalt and mixing of dacite in the rootzone of a large rhyolite chamber: inclusions and pumices from the Rattlesnake Tuff, Oregon   总被引：3，自引：0，他引：3  

Martin J. Streck  Anita L. Grunder 《Contributions to Mineralogy and Petrology》1999,136(3):193-212

 A variety of cognate basalt to basaltic andesite inclusions and dacite pumices occur in the 7-Ma Rattlesnake Tuff of eastern Oregon. The tuff represents ∼280 km³ of high-silica rhyolite magma zoned from highly differentiated rhyolite near the roof to less evolved rhyolite at deeper levels. The mafic inclusions provide a window into the processes acting beneath a large silicic chamber. Quenched basaltic andesite inclusions are substantially enriched in incompatible trace elements compared to regional primitive high-alumina olivine tholeiite (HAOT) lavas, but continuous chemical and mineralogical trends indicate a genetic relationship between them. Basaltic andesite evolved from primitive basalt mainly through protracted crystal fractionation and multiple cycles (≥10) of mafic recharge, which enriched incompatible elements while maintaining a mafic bulk composition. The crystal fractionation history is partially preserved in the mineralogy of crystal-rich inclusions (olivine, plagioclase ± clinopyroxene) and the recharge history is supported by the presence of mafic inclusions containing olivines of Fo₈₀. Small amounts of assimilation (∼2%) of high-silica rhyolite magma improves the calculated fit between observed and modeled enrichments in basaltic andesite and reduces the number of fractionation and recharge cycles needed. The composition of dacite pumices is consistent with mixing of equal proportions of basaltic andesite and least-evolved, high-silica rhyolite. In support of the mixing model, most dacite pumices have a bimodal mineral assemblage with crystals of rhyolitic and basaltic parentage. Equilibrium dacite phenocrysts are rare. Dacites are mainly the product of mingling of basaltic andesite and rhyolite before or during eruption and to a lesser extent of equilibration between the two. The Rattlesnake magma column illustrates the feedback between mafic and silicic magmas that drives differentiation in both. Low-density rhyolite traps basalts and induces extensive fractionation and recharge that causes incompatible element enrichment relative to the primitive input. The basaltic root zone, in turn, thermally maintains the rhyolitic magma chamber and promotes compositional zonation. Received: 1 June 1998 / Accepted: 5 February 1999  相似文献   

Piping dynamics in mid‐altitude mountains under a temperate climate: Bieszczady Mountains,eastern Carpathians          下载免费PDF全文

Anita Bernatek‐Jakiel  Michał Jakiel  Kazimierz Krzemień 《地球表面变化过程与地形》2017,42(9):1419-1433

Piping has been recognized as an important geomorphic, soil erosion and hydrologic process. It seems that it is far more widespread than it has often been supposed. However, our knowledge about piping dynamics and its quantification currently relies on a limited number of data for mainly loess‐derived areas and marl badlands. Therefore, this research aimed to recognize piping dynamics in mid‐altitude mountains under a temperate climate, where piping occurs in Cambisols, not previously considered as piping‐prone soils. It has been expressed by the estimation of erosion rates due to piping and elongation of pipes in the Bere?nica Wy?na catchment in the Bieszczady Mountains, eastern Carpathians (305 ha, 188 collapsed pipes). The research was based on the monitoring of selected piping systems (1971–1974, 2013–2016). Changes in soil loss vary significantly between different years (up to 27.36 t ha^?1 yr^?1), as well as between the mean short‐term erosion rate (up to 13.10 t ha^?1 yr^?1), and the long‐term (45 years) mean of 1.34 t ha^?1 yr^?1. The elongation of pipes also differs, from no changes to 36 m during one year. The mean total soil loss is 48.8 t ha^?1 in plots, whereas in the whole studied catchment it is 2.0 t ha^?1. Hence, piping is both spatially and temporally dependent. The magnitude of piping in the study area is at least three orders of magnitude higher than surface erosion rates (i.e. sheet and rill erosion) under similar land use (grasslands), and it is comparable to the magnitude of surface soil erosion on arable lands. It means that piping constitutes a significant environmental problem and, wherever it occurs, it is an important, or even the main, sediment source. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献