Ellipticity of dark matter haloes with galaxy–galaxy weak lensing     

Rachel Mandelbaum  Christopher M. Hirata  Tamara Broderick  Uro&#; Seljak  Jonathan Brinkmann 《Monthly notices of the Royal Astronomical Society》2006,370(2):1008-1024

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The role of fulvic acid composition in the photosensitized degradation of aquatic contaminants   总被引：2，自引：0，他引：2  

Jennifer J. Guerard  Penney L. Miller  Tamara D. Trouts  Yu-Ping Chin 《Aquatic Sciences - Research Across Boundaries》2009,71(2):160-169

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Stochastic downscaling method: application to wind refinement     

Frédéric Bernardin  Mireille Bossy  Claire Chauvin  Philippe Drobinski  Antoine Rousseau  Tamara Salameh 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(6):851-859

In this article, we propose a new stochastic downscaling method: provided a numerical prediction of wind at large scale, we aim to improve the approximation at small scales thanks to a local stochastic model. We first recall the framework of a Lagrangian stochastic model borrowed from Pope. Then, we adapt it to our meteorological framework, both from the theoretical and numerical viewpoints. Finally, we present some promising numerical results corresponding to the simulation of wind over the Mediterranean Sea.  相似文献   

Silicic magma petrogenesis in Iceland by remelting of hydrothermally altered crust based on oxygen isotope diversity and disequilibria between zircon and magma with implications for MORB   总被引：1，自引：0，他引：1  

Ilya Bindeman  Andrey Gurenko  Tamara Carley  Calvin Miller  Erwan Martin  Olgeir Sigmarsson 《地学学报》2012,24(3):227-232

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New insights into the nature of the Late Riphean Eosolenides     

Tamara N. German  Victor N. Podkovyrov   《Precambrian Research》2009,173(1-4):154

Studies of a morphologically diverse population of Eosolenides, organic-walled macrofossils from the Upper Mesoproterozoic (1015–1025 Ma) Lakhanda Group of southeastern Siberia, suggest that these elongate fossils may be remains of soft-bodied organisms having tube-grade organization. The compressed, originally cylindrical fossils, of more or less constant diameter along their length, are subdivided by transverse membranes into a regular series of distinct chamber-like segments. The lateral walls of the segmented tubes are double-layered, the outer sheath- or cuticle-like layer of which was originally flexible and commonly exhibits very fine and closely spaced transverse striations. The presence of structures inferred to be basal attachment disks suggests a benthic habit, whereas the morphological variability of the population can be interpreted as showing that their body shape changed as the organisms grew and increased markedly in length. Reproduction may have been by budding. An important peculiarity exhibited by these tubular fossils is the presence within many specimens of small spherical unicells, interpreted possibly to be algal endosymbionts. Although in some respects these fossils resemble cnidarians, the biological affinities of Eosolenides tubes remain enigmatic.  相似文献   

Behaviour of metals and nutrients in soils and groundwater of a karst polje   总被引：2，自引：0，他引：2  

Tamara Markovic  Slobodan Miko  Sanja Kapelj  Renato Buljan  Ozren Larva  Zoran Peh 《Journal of Geochemical Exploration》2006,88(1-3):124

The Croatian south part of the country is mainly composed of strongly krastified carbonate rocks. Also in this south part of Croatia is lacking of large depressions and poljes with thick covers. Some karst poljes and depressions may have thick covers, like for example the Vransko polje. The Vransko polje is characterised by an intensive agricultural activity. At the centre of the polje is located a karst spring (Turanjsko jezero), which is used for the water supply of the town Biograd and its surroundings. Total metals, nutrients (nitrate, ammonia, phosphate), organic matter content and cation exchange capacity (CEC) were measured in soil samples collected from the polje. Metals and nutrients were also measured in the water samples of channel Kotarka (which is passing through the area) and three springs (Turanjsko jezero, Kakma and Tinj). Measured total concentrations of metals of soil samples were treated by R-cluster multivariate statistical analysis. The result of statistical analysis showed grouping of metals with similar behaviour. Content of metals and nutrients were low in the spring samples but high in the water sample of the channel Kotarka, because the channel drains the water from the surroundings. Although agricultural activity in the Vransko polje is high, there is no high anthropogenic influence on groundwater and soil. They are both of good quality.  相似文献   

Time dependent IRM acquisition as a tool to quantify the abundance of ultrafine superparamagnetic magnetite in loessic soils     

Tamara A. Machac  C. William Zanner  Christoph E. Geiss 《Geophysical Journal International》2007,169(2):483-489

The time dependence of Isothermal Remanent Magnetization acquisition (tIRM) is a rapid, sensitive and inexpensive way to quantify the presence of ultrafine ferrimagnetic grains straddling the superparamagnetic–single domain grain size boundary, well suited for use in small rock magnetic laboratories. The technique is very selective to the presence of grains with a diameter of approximately 25 nm, and tIRM results correlate well with measurements of frequency dependent susceptibility without the need of correcting for the presence of paramagnetic minerals. A simple IRM acquisition model can be used to obtain quantitative abundance estimates for these ultrafine magnetic grains. Application of tIRM measurements to eleven soil profiles from the Midwestern United States shows that the abundance of ultrafine particles increases with precipitation, as long as the mean annual precipitation is below 850 mm a⁻¹. Sites that developed under more humid conditions show a decrease in tIRM and likely SP abundance, probably caused by increased iron reduction and translocation during more common periods of reducing conditions.  相似文献   

Configuration of the upper boundary of the ionosphere     

Tamara L. Gulyaeva 《Acta Geophysica》2007,55(2):253-266

Variations of the upper boundary of the ionosphere (UBI) are investigated based on three sources of information: (i) ionosonde-derived parameters: critical frequency foF2, propagation factor M3000F2, and sub-peak thickness of the bottomside electron density profile; (ii) total electron content (TEC) observations from signals of the Global Positioning System (GPS) satellites; (iii) model electron densities of the International Reference Ionosphere (IRI^*) extended towards the plasmasphere. The ionospheric slab thickness is calculated as ratio of TEC to the F2 layer peak electron density, NmF2, representing a measure of thickness of electron density profile in the bottomside and topside ionosphere eliminating the plasmaspheric slab thickness of GPS-TEC with the IRI^* code. The ratio of slab thickness to the real thickness in the topside ionosphere is deduced making use of a similar ratio in the bottomside ionosphere with a weight Rw. Model weight Rw is represented as a superposition of the base-functions of local time, geomagnetic latitude, solar and magnetic activity. The time-space variations of domain of convergence of the ionosphere and plasmasphere differ from an average value of UBI at ∼1000 km over the earth. Analysis for quiet monthly average conditions and during the storms (September 2002, October–November 2003, November 2004) has shown shrinking UBI altitude at daytime to 400 km. The upper ionosphere height is increased by night with an ‘ionospheric tail’ which expands from 1000 km to more than 2000 km over the earth under quiet and disturbed space weather. These effects are interposed on a trend of increasing UBI height with solar activity when both the critical frequency foF2 and the peak height hmF2 are growing during the solar cycle.  相似文献   

Freezing rain events: a major weather hazard in the conterminous US   总被引：3，自引：0，他引：3  

Tamara G. Houston  Stanley A. Changnon 《Natural Hazards》2007,40(2):485-494

Freezing rain (FZRA) is well documented as a major weather hazard, producing damage to structures, the environment, and humans, and delaying various operations such as transportation. Assessing the risk of freezing rain events requires information for various areas of the nation about the frequency, duration, and intensity of these events along with the associated weather conditions that affect the damage caused by freezing rain. This includes temperatures (dry and wet bulb), the amount of precipitation, and winds during freezing rain. The purpose of this work was to develop a national and regional climatology of freezing rain events in the US for the period of 1928–2001 to addresses these conditions.  相似文献   

Toxicity of tributyltin in the marine mollusc Mytilus edulis     

Hagger JA  Depledge MH  Galloway TS 《Marine pollution bulletin》2005,51(8-12):811-816

Our previous studies have demonstrated that tributyltin (TBT) is genotoxic to the early life stages of marine mussels and worms. Here, the toxicity of TBT to adult organisms was determined using a suite of biomarkers designed to detect cytotoxic, immunotoxic and genotoxic effects. Exposure of adult mussels, Mytilus edulis, to environmentally realistic concentrations of TBTO for 7 days resulted in a statistically significant decrease in cell viability at concentrations of 0.5 μg/l and above. TBT had no effect on phagocytic activity or antioxidant capacity (FRAP assay). There was a statistically significant increase in DNA damage detected using the comet and micronucleus assays between the controls and 0.5, 1 and 5 μg/l of TBTO (P > 0.0005). Furthermore there was a strong correlation between DNA strand breaks (comet assay) and formation of micronuclei (P = 0.0005; R² = 61.5%). Possible mechanisms by which TBT could damage DNA either directly or indirectly are discussed including the possibility that TBT is genotoxic due to its ability to disrupt calcium homeostasis.  相似文献