bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion Exchange Behavior of the Febex Bentonite. 1. Na/K, Na/Mg and Na/Ca Experimental Exchange Isotherms
Authors: Huertas F.J. , Carretero P. , Delgado J. , Linares J. , Samper J.
Published: May 2011

Na/K, Na/Mg, and Na/Ca exchange isotherms have been experimentally determined for the FEBEX bentonite. Na-homoionized FEBEXbentonite was reacted at room temperature with mixedsalt dissolution of NaCl/KCl, NaCl/MgCl2, or NaCl/CaCl2, while keeping a total cation normality of 0.5 eq L-1. Isotherm exchange experiments were performed using ten (duplicated)experimental points, which cover the complete range of the corresponding binary equivalent fractions. Results indicate that for the Na/K exchange reaction, Vanselow coefficients are larger than one, what is in agreement with the tendency of the smectite of having greater affinity for K than for Na. The exchange constant decreases as K progressively replaces Na in the smectite. This tendency ends when the equivalent fraction of potassium, EK, reaches a value of around 0.250.3. From this point to higher K contents, it remains nearly constant irrespective of EK but slightly decreasing again at values near one. The Vanselow selectivity coefficient for the Na/Mg isotherm indicates a preference for the divalent cation. It is nearly constant (Kv ≍ 5.6) for EMg < 0.6, but increases up to 10.2 for a nearly Mg-saturated smectite.

The Na/Ca exchange resembles that of Na/Mg, although the selectivity coefficients are larger (Kv ≍ 7.0 for ECa < 0.6). The comparison of the selectivity coefficients for the Na/Mg and Na/Ca exchange reactions indicates that the smectite has a slightly higher affinity for Ca than for Mg. This result is consistent with those observed for the Wyoming bentonite.
Laboratory Examination of Microbial Perturbations in a Granitic Environment
Authors: M. West J. , Hama K. , Bateman K. , Coombs P. , Hards V. , Milodowski A. E. , Wetton P. , Yoshida H.
Published: May 2011

Microbial activity can have a significant impact on geochemical processes as it can influence mineral dissolution and precipitation, pH, alkalinity and redox. Experiments were conducted to study the rock-water and microbial interactions, specifically to examine the influence of microbes on the groundwater environment in fractured crystalline rock. These used combinations of crushed Äspö Diorite, Äspö groundwater with iron and sulphate reducing bacteria in columns and continuously stirred tank reactors under both anaerobic and aerobic conditions. Results showed loss (dissolution and/or mobilization) of fine grained crushed material (<50 μm) which had originally adhered to grain surfaces in the starting material. The mobilized fines were subsequently trapped on biofilms developed between grains. There was also evidence for the formation of smectite (not present in the starting materials) which, together with the trapping of translocated fines in intergranular pore throats by biofilms, resulted in blockage of the column experiments. The degree of mineralogical alteration and/or pore blocking was greater in the experiments when bacteria were present and occurred under anaerobic conditions. Little evidence for rock-water interactions was seen in the chemical analysis data for all the experiments. Modelling of the fluids showed them to be saturated with respect to clay minerals. The observed mineralogical changes seem to reflect alteration occurring in microbially mediated microenvironments close to mineral surfaces. Consequently, these changes may be too small to be detected by the chemical analysis of the bulk fluid. These experiments have shown that microbial activity can impact on fluid flow through porous media even in nutrient poor conditions. In addition, the formation of new clay minerals on pore-surfaces is potentially important for ion exchange and sorption reactions.
Behavior of High Performance Concrete Under High Temperature (60-450°C) for Surface Long-Term Storage: Thermo-Hydro-Mechanical Residual Properties
Authors: Gallé C. , Sercombe J. , Pin M. , Arcier G. , Bouniol P.
Published: May 2011

After various thermal treatments (up to 450°C), residual thermo-hydro-mechanical (T-H-M) properties of two OPC high performance concretes (HPC) were analyzed in the context of surface long-term storage. Materials were prepared with silico-calcareous aggregates (standard HPC) and hematite aggregates (heavy HPC). The initial microstructural (porosity ≈10%) and transport (gas permeability ≈10-19 m2) properties are similar for both concretes. As far as the mechanical aspect is concerned, heavy HPC shows a higher compressive strength and elastic modulus than standard HPC (78 and 63 MPa, 81 and 49 GPa, respectively). Heavy HPC is also characterized by a higher thermal conductivity (7.3 W m-1 K-1 compared to 2.7 W m-1 K-1 for standard concrete). Results analysis show that thermo-hydro-mechanical damages are smaller for heavy HPC. Between 60 and 250°C, the elastic modulus and the compressive strength of standard HPC decrease by 40% and 16%, respectively. For heavy HPC, these parameters respectively decrease by 10% and 4%. A similar trend was observed for thermal conductivity evolution. Gas permeability and porosity data confirm the good behavior of heavy HPC. As a conclusion, hematite HPC seems to provide more interesting T-H-M residual properties than standard HPC. Limited thermal expansion and thermal gradients induced by hematite are probably responsible of this behavior.
The Maralinga Rehabilitation Project
Authors: Perkins C. , Harris J.
Published: May 2011

The $108 million Maralinga Rehabilitation Project to clean-up the former British atomic test site in South Australia, the largest remediation of this type, was completed in 2000. The rehabilitation was agreed by the Commonwealth and South Australian Governments and the Maralinga Tjarujta traditional owners, following methods identified by technical experts. The rehabilitation permits unrestricted access to about 90% of the former restricted area, but excludes full time occupation of the remaining 120 square kilometers.

The clean-up has largely been directed at remediating plutonium contamination caused by minor trials. The clean-up involved two components, the removal of surface soil from the more contaminated areas, and the treatment of contaminated debris pits. Over 350,000 cubic meters of soil and debris was removed over about 2 square kilometers of land, and was buried in 10-15 meter deep trenches under a capping of clean soil of at least 5 meters. Treatment of contaminated pit debris at various sites has involved in situ vitrification, a process which involves application of an electric current to heat and melt debris encasing the contaminated material in a vitric/ceramic block, and exhumation of the contaminated debris and at depths of at least 5 meters.

The independent regulator to the project, the Australian Radiation Protection and Nuclear Safety Agency, has indicated that the clean-up of the test sites has met the radiological criteria laid down in the original plan. Discussions are progressing with the South Australian Government and the Maralinga Tjarujta traditional owners as to the long-term management of the site, and the possible hand back of the land from the Commonwealth to South Australia for addition to the Maralinga Tjarutja freehold lands.
Radionuclide Transport Calculations in the Safety Assessment SR 97
Authors: Lindgren M. , Lindström F.
Published: May 2011

This study treats radionuclide transport calculations for a canister defect scenario in the safety assessment SR 97, which concerns a deep repository for spent nuclear fuel of the KBS-3 type in Sweden. The aims of the calculations are to:

Quantitatively describe the radionuclide transport.

Show the impact of uncertainty in input data and show which parameters govern the calculated release rates.

Compare three different real sites in Sweden (Aberg, Beberg and Ceberg) with each other and with dose limits given in Swedish regulations (none of the sites is considered in the on-going localization process). Only briefly described in this paper.

Illustrate the impact of the different barriers in the system.

Deterministic calculations illustrate the radionuclide transport for reasonable conditions. Uncertainty cases show the influence of the uncertainty for data related to different parts of the repository system by systematically giving them pessimistic values while all others are reasonable. Simplified probabilistic calculations have also been performed.

The analysis shows that the most important parameters in the near field are the number of defective canisters and the instant release fraction. In the far field the most important uncertainties affecting release and retention are connected to permeability and connectivity of the fractures in the rock. The dose rate in the biosphere is essentially controlled by the possibilities of dilution.

The calculated maximum doses for the hypothetical repositories are well below the dose limits, and hence they meet the acceptance criteria for a deep repository for spent fuel.
Using Results from Tru Experiments for WIPP to Determine Model Development and Needed Experimental Programs
Authors: Silva M. K. , Oversby V. M.
Published: May 2011

The Waste Isolation Pilot Plant (WIPP) is located at a depth of 655 m in bedded salt at a site about 40 km east of Carlsbad, New Mexico.The 1996 U. S. Department of Energy (DOE) application for certification by the U. S. Environmental Protection Agency (EPA) included results of a performance assessment (PA) for the planned repository.After the EPA certified the facility in May, 1998, emplacement of contact handled transuranic waste (CHTRU) began in March, 1999.The WIPP facility must undergo a recertification by EPA every 5 years to demonstrate compliance with disposal regulations.Performance assessment is expected to be a key part of the recertification process.The PA will include probabilistic calculations to predict the release of actinides to the accessible environment over a 10,000 year period using a variety of plausible scenarios.The 1996 PA used a model for Pu(IV) solubility based on Th data and the assumption of analogous behavior for all actinides in the (IV) oxidation state.That model did not allow for mobility between the various possible oxidation states of Pu.The possible effects of increases in solubility of Pu through complexation with organic ligands was also not included in the PA because it was argued by DOE that such complexation would be insignificant. Subsequent data from tests using actual TRU wastes show strong evidence that the importance of organic ligands and the potential for multiple oxidation states must be carefully considered in estimating the expected solution concentrations of Pu in WIPP brines.This paper reviews the present state of knowledge of the behavior of Pu-containing wastes in contact with brines similar to those expected to be important for the WIPP repository, recent advances in understanding of the nature of Pu-oxide phases, and analytical methods that have high sensitivity for Pu speciation. A conceptual model for Pu in TRU wastes is presented and a series of steps - including experiments and calculations - that could led to an improved basis for the PA calculations to be done during the WIPP recertification process is outlined.
Modeling of Near Field Actinide Concentrations in Radioactive Waste Repositories in Salt Formations: Effect of Buffer Materials
Authors: Schuessler W. , Kienzler B. , Wilhelm S. , Neck V. , Kim J.I.
Published: May 2011

Engineered barrier systems are designed to reduce the near field actinide concentrations in case of water penetration into a repository. In this paper, the influence of buffer materials, such as MgO/CaO and clays, on the solubilities of Am, Np, Pu, and U is studied. The analysis is performed for low level cemented waste forms in a rock salt formation in contact with MgCl2 saturated salt brine (Q-brine).

The evolution of the geochemical milieu by cement corrosion is calculated using reaction path modeling supported by the code EQ3/6. The influence of different buffer materials is analyzed with respect to their impact on the solution chemistry and corresponding actinide concentrations.
Status of the Pangea International Repository Feasibility Studies
Authors: Mccombie C. , Kurzeme M.
Published: May 2011

The potential technical, scientific, safety, security, environmental and economic advantages of implementation of deep geologic repositories for the disposal of nuclear waste within an international framework were outlined in papers from the IAEA and from the Pangea organization over the past three years. Of increasing importance are the security and non-proliferation benefits which could result from having closely supervised centralized repositories for declared surplus fissile materials resulting from disarmament activities in nuclear weapon states.

The Pangea concept is for repositories sited on technical and safety grounds independent of national boundaries. The sites would be in geologic formations situated in flat, stable, arid regions, where the convincing demonstration of long-term safety should be easier to achieve. Pangea identified several potential host regions of the world which warrant further investigation of their suitability for an international repository. As yet a formal feasibility study has been initiated only in Australia. This was allocated first priority due to the vastness of the region with potentially suitable geology, also because of its stable governmental system, its strong environmental record and non-proliferation credentials. Australia also has a strong anti-nuclear movement, no nuclear power plants, but an important uranium mining industry.

Hence progress to date in Australia has been mixed. Political resistance has culminated in legislation in Western Australia prohibiting the construction and operation of a repository for the disposal of imported nuclear waste, unless approved by both houses of the WA Parliament. Within the scientific, technical and business communities, there has been much greater readiness to objectively weigh up the pros and cons of hosting an international disposal facility. The public reaction has been mixed, with some individuals and communities strongly opposing the concept whilst others are prepared to seek information before judging the case on its merits.

Meanwhile, on the world stage, the generic concept of international disposal facilities continues to be elaborated - including defining better the roles which such facilities could play in management and disposition of surplus weapons material. In addition contacts are being strengthened with potential users of such facilities and actions being taken to intensify Pangea's activities in other countries identified as having potential host regions for a high-isolation repository of the type proposed by Pangea.
Simulation of the Waste Glass Behavior in a Loamy Soil of the Wet Repository Site
Authors: Ojovan M.I. , Ojovan N.V. , Startceva I.V. , Chuikova G.N. , Barinov A.S.
Published: May 2011

A model developed for description of waste glass corrosion has been applied to assess the radionuclide release from real radioactive (intermediate level) vitrified material over extended storage periods. Field data generated during the long-term testing of the prototype waste glass packages were mathematically processed and the derived parameters used in model calculations. Regardless of the corrosive saturated conditions of the wet near-surface repository, the fairly high safety of trench disposal has been demonstrated for borosilicate glass containing real NPP- operational waste.
Scenarios Selection for a Simple Concept Landfill
Authors: Badie Olivier-Moana , Goldschmidt Frédéric , Besnus François , Péres Jean-Marc
Published: May 2011

Scenarios are used to deal with uncertainty on the evolution of complex systems. The scenario selection methodologies also have to provide a basis for reflexion and traceability of the reasoning. In the case of a simple concept landfill, a methodology that fulfils these requirements has been developed. It distinguishes on the one hand the landfill evolution, and on the other hand, the human behavior evolution. It is based on three steps: (i) characterization of the landfill itself, in order to define situations leading to releases of radionuclides, (ii) characterization of the human behavior in order to define situations leading to intrusions, and (iii) characterization of the interfaces between the two subsystems, in order to identify situations which could lead to a radiological risk for man. The method has been applied to performance assessment for landfill of uranium mill tailings. It has led to one reference scenario, and five altered scenarios taking into account specific landfill evolutions such as loss of covering or loss of integrity of the dike, and human intrusions such as housing on the site of landfill or excavation of the site.
Development and Analysis of Scenarios for a Permanent Repository for Radioactive Wastes in Salt Rock
Authors: Keller S.
Published: May 2011

Scenarios were developed and analyzed as part of a long-term safety analysis of a permanent repository for radioactive wastes. A procedure is described by which features, events, and processes (FEP) at a specific site can be evaluated for the long-term safety assessment of a permanent repository for radioactive waste. These FEPs can be weighted according to selected criteria and combined to scenarios using a conceptual model of the site.
Application of Supplementary Safety Indicators for H12 Performance Assessment
Authors: Takasu A. , Naito M. , Umeki H. , Masuda S.
Published: May 2011

The safety of a geological disposal system can be assessed using defined indicators such as risk and dose level, which directly measure radiological effects on human beings. Since the safety assessment of a geological disposal system covers a very long period of time, there are inherent uncertainties involved in assumptions about future human activities and environmental conditions, which increase the longer the time frame becomes.

To allow for some of these uncertainties, it has been proposed to supplement assessment results based on dose levels (or equivalent risks) by other independent indicators, without relying on assumptions made in the biosphere model. Safety indicators such as nuclide concentration, flux and radiotoxicity can usefully supplement dose calculations in the evaluation of overall system performance. In particular, they may be more indicative of the isolation capability of a disposal system and the potential risks of radioactive waste disposal over the very long timescales of safety assessment.

In the H12 study, which is the project aimed at establishing a technical basis for HLW disposal in Japan, supplementary safety indicators have been applied to increase confidence in the safety assessment. The nuclide concentrations evaluated in the geosphere and biosphere in the H12 repository system were compared with measurements of naturally occurring nuclides. The comparison indicated that the concentration of radionuclides released from the repository would be several orders of magnitude lower than that of natural radionuclides. This suggests that application of supplementary safety indicators could increase the reliability of long-term safety by more rigorous measurements of concentrations of naturally occurring radionuclides in the characterization phase at a specific site, which will be compared with concentrations of relevant nuclides predicted by site-specific performance assessment models.
Alteration of Uranium-Rich Microlite
Authors: Gieré R. , Buck E. C. , Guggenheim R. , Mathys D. , Reusser E. , Marques J.
Published: May 2011

Microlite, a Ta-rich member of the pyrochlore group, occurs in 440 Ma old lithium pegmatites in Mozambique and exhibits a pronounced growth zoning, with a U-free core surrounded by a U-rich rim (UO2≤ 17 wt%). Subsequent to the uplift of the host rock, microlite was subjected to intense low-temperature alteration during which Na, Ca and F were leached from the microlite crystals. This alteration, resulting from exposure to tropical conditions, also led to localized redistribution of radiogenic Pb (formation of plumbomicrolite) and to hydration of microlite, but U remained immobile. The low-temperature alteration effects are only observed in the U-rich rim, which is characterized by abundant microfractures. As demonstrated by electron diffraction images and powder X-ray patterns, the U-rich rim is largely metamict. Our investigation illustrates the importance of natural analogues in evaluating the durability of pyrochlore-based nuclear waste-form materials over geologic time.
Field and Laboratory Examination of Uranium Microcrystallization and Its Role in Uranium Transport
Authors: Murakami Takashi , Ohnuki Toshihiko , Isobe Hiroshi , Sato Tsutomu
Published: May 2011

Adsorption is believed to be a dominant mechanism of uranium distribution between solid and solution, and thus, to play a major role in uranium transport. Because iron oxides and hydroxides are abundant at the Earth's surface and are great adsorbents of uranium, we have examined natural rocks that contain iron minerals along with uranium, and also carried out Fe-U coprecipitation and aging experiments to find how uranium is distributed between Fe minerals. Transmission and scanning electron microscopy reveals that microcrystals (10-50 nm) of metatorbernite (Cu(UO2)2(PO4)28H2O) are scattered within nodules consisting of fine-grained (2-50 nm) goethite and hematite, where the ground water is undersaturated with respect to metatorbernite, for the natural rocks from the Koongarra ore deposit, Australia. The microscopy also reveals that microcrystals (a few nm) of dehydrated schoepite ((UO2)O0.25(OH)1.5) are formed among fine-grained hematite after aging coprecipitated Fe-U in the laboratory, and the solution is undersaturated with respect to schoepite. The beam size of microscopes is found to be important for the chemical analysis of such microcrystals. We detect a strong signal of uranium for a beam size < 40 nm; whereas a weak uranium signal is obtained for a beam size > 150 nm. Our results indicate that such a weak uranium signal should not be taken as a result of homogeneously distributed uranium over goethite and hematite surfaces by, for instance, adsorption. The micrcrystallization observed in both the field and laboratory suggests that fine grained uranyl minerals play a major role in uranium transport and migration.
Geochemistry of Hydrothermal Veins Containing Zirconolite and Betafite at Adamello, Italy
Authors: Gieré R. , Lumpkin G.R. , Williams C.T. , Smith K.L. , Payne T.E. , Mcglinn P.J. , Hart K.P. , Oberli F.
Published: May 2011

Hydrothermal veins containing zirconolite and betafite occur in dolomite marbles at the contact with a tonalite intrusion of the Adamello batholith, Italy. The veins display four distinct mineral zones and are highly enriched in Th, U, Ti, Zr, Nb, and rare earth elements (REE) relative to their host rock. Wide ranges in concentration of these elements and distinct inter- element fractionation trends exist across the four vein zones. The behavior of Th closely reflects that of P, Ti, Nb, and heavy REE, but was distinct from that of U, Zr and light REE (La to Sm). The presence and composition of refractory minerals such as zirconolite, betafite, uraninite, thorianite, baddeleyite, rutile, allanite, and aeschynite provide evidence for the transport of Ti, Zr, Nb, REE, and actinides by a fluid, which was further characterized by a low pH and high contents of F, P, Cl and H2S. Thermodynamic analysis of these veins indicates that they were formed at 550-600°C, 200 MPa total pressure, and from a fluid derived from the tonalite. Mineralogical and textural observations suggest that crystallization of the refractory minerals was in part induced by precipitation of fluorapatite and sulfides. The geochemical data further indicate that precipitation of light REE was induced by the fluid/wall-rock interaction which led to a significant dilution of the fluid by CO2. The studied veins provide an example of high- temperature transport of actinides and REE in the Earth's crust and show that these elements can be precipitated from a fluid and subsequently immobilized by zirconolite and betafite, two important actinide hosts in ceramic nuclear waste forms.
Cesium and Lead Uptake by CSH Phases of Hydrated Cement
Authors: Pointeau I. , Marmier N. , Fromage F. , Fedoroff M. , Giffaut E.
Published: May 2011

As Kd from radwaste elements in concrete systems show a wide range of values, a modelling of cesium and lead immobilization in Calcium Silicate Hydrate (CSH, xCaO.SiO2.H2O, with 0.7 (aged cements)<Ca/Si<1.8 (fresh cements)) matrix has been developed. This model accounts for radwaste surface binding mechanisms on silanol sites (>SiOH) and precipitation equilibria. Values of Kd from cesium and lead in CSH matrix can thus be calculated with Ca/Si evolution and ionic strength effect. Predictive calculations have been carried out with success with different Ca/Si ratios, ionic strengths and liquid/solid ratios, and results are well superimposed with experimental isotherm data. If the CSH really allow accounting for the radwaste behavior in hydrated cement matrices, this model can be used in safety assessment calculations, with varying pH and [Ca2+] as cement degradation state parameters.
Performance of Matrix Representation with Parsimony for Inferring Species from Gene Trees
Authors: Wang Yuancheng , Degnan James H
Published: May 2011

Phylogenomic datasets often contain sequence alignments on different subsets of taxa for different genes. A major goal of phylogenetics is often to combine estimated gene trees from many loci into an overall estimate of a species tree. When data are missing for some combinations of genes and taxa, supertree methods can be used to combine gene trees on different subsets of taxa into an overall tree. However, studies of the performance of supertree methods when gene tree conflict is due to incomplete lineage sorting are needed to understand their statistical properties in this setting.

We find that Matrix Representation with Parsimony (MRP), the most commonly used supertree method, can in many cases infer the species tree in spite of high levels of conflict in the input gene trees. However, for some species trees with short branches, MRP can be increasingly likely to return a tree other than the species tree as the number of loci increases. In some cases, deleting taxa at random or using estimated (rather than known) gene trees can either improve or hinder MRP for recovering the species tree.

Although MRP is able to handle large amounts of conflict in the input gene trees, MRP is not statistically consistent for estimating species trees when gene trees arise under the multispecies coalescent model. However, triplet MRP is statistically consistent in this setting.
On the Economics of Climate Policy
Authors: Becker Gary S. , Murphy Kevin M. , Topel Robert H.
Published: May 2011

We analyze the central features of economic policies to mitigate climate change. The basic structure of Pigouvian “carbon pricing” is shown to follow from a standard Hotelling problem for the intertemporal pricing of an exhaustible resource. We extend this analysis to consider the strength and timing of research incentives, the costs of implementation delay and the impact of anticipated future technologies on current carbon prices. We study a variety of issues related to the valuation of climate investments, including uncertainty as to the future timing and distribution of climate impacts and the appropriate social rate of discount for valuing policies. Under reasonable circumstances the insurance properties of climate investments may warrant unusually low discount rates. We use the same framework to argue that policy makers in developing countries will discount the expected returns from climate investments more heavily, because such investments have weaker insurance value in the developing world.
Cross-Talk Between Interferon-γ and Hedgehog Signaling Regulates Adipogenesis
Authors: Todoric Jelena , Strobl Birgit , Jais Alexander , Boucheron Nicole , Bayer Martina , Amann Sabine , Lindroos Josefine , Teperino Raffaele , Prager Gerhard , Bilban Martin , Ellmeier Wilfried , Krempler Franz , Müller Mathias , Wagner Oswald , Patsch Wolfgang , Pospisilik J. Andrew , Esterbauer Harald
Published: May 2011

OBJECTIVE

T cells and level of the cytokine interferon-γ (IFN-γ) are increased in adipose tissue in obesity. Hedgehog (Hh) signaling has been shown to potently inhibit white adipocyte differentiation. In light of recent findings in neurons that IFN-γ and Hh signaling cross-talk, we examined their potential interaction in the context of adipogenesis.

RESEARCH DESIGN AND METHODS

We used Hh reporter cells, cell lines, and primary adipocyte differentiation models to explore costimulation of IFN-γ and Hh signaling. Genetic dissection using Ifngr1−/− and Stat1−/− mouse embryonic fibroblasts, and ultimately, anti–IFN-γ neutralization and expression profiling in obese mice and humans, respectively, were used to place the findings into the in vivo context.

RESULTS

T-cell supernatants directly inhibited hedgehog signaling in reporter and 3T3-L1 cells. Intriguingly, using blocking antibodies, Ifngr1−/− and Stat1−/− cells, and simultaneous activation of Hh and IFN-γ signaling, we showed that IFN-γ directly suppresses Hh stimulation, thus rescuing adipogenesis. We confirmed our findings using primary mouse and primary human (pre)adipocytes. Importantly, robust opposing signals for Hh and T-cell pathways in obese human adipose expression profiles and IFN-γ depletion in mice identify the system as intact in adipose tissue in vivo.

CONCLUSIONS

These results identify a novel antagonistic cross-talk between IFN-γ and Hh signaling in white adipose tissue and demonstrate IFN-γ as a potent inhibitor of Hh signaling.
Natural convection flow in a square cavity with internal heat generation and a flush mounted heater on a side wall
Authors: Rahman Md. Mustafizur , Mamun M. Arif Hasan , Billah M. Masum , Rahman Saidur
Published: May 2011

In this study natural convection flow in a square cavity with heat generating fluid and a finite size heater on the vertical wall have been investigated numerically. To change the heat transfer in the cavity, a heater is placed at different locations on the right vertical wall of the cavity, while the left wall is considered to be cold. In addition, the top and bottom horizontal walls are considered to be adiabatic and the cavity is assumed to be filled with a Bousinessq fluid having a Prandtl number of 0.72. The governing mass, momentum and energy equations along with boundary conditions are expressed in a normalized primitive variables formulation. Finite Element Method is used in solution of the normalized governing equations. The parameters leading the problem are the Rayleigh number, location of the heater, length of the heater and heat generation. To observe the effects of the mentioned parameters on natural convection in the cavity, we considered various values of heater locations, heater length and heat generation parameter for different values of Ra varying in the range 102 to 105. Results are presented in terms of streamlines, isotherms, average Nusselt number at the hot wall and average fluid temperature in the cavity for the mentioned parameters. The results showed that the flow and thermal fields through streamlines and isotherms as well as the rate of heat transfer from the heated wall in terms of Nusselt number are strongly dependent on the length and locations of the heater as well as heat generating parameter.DOI: 10.3329/jname.v7i2.3292
Numerical study of unsteady flow around a cavitating hydrofoil
Authors: Karim M. M. , Mostafa N. , Sarker M. M. A.
Published: May 2011

This paper presents a numerical study of the non-cavitating and cavitating flow around CAV 2003 hydrofoil. The phenomenon of cavitation is modeled through a mixture model. For the numerical solution of cavitating flow a bubble dynamics cavitation model is used to describe the generation and evaporation of vapor phase. The non-cavitating study focuses on the influence of the turbulence model and different mesh sizes used in the computation. Three turbulence models such as Spalart-Allmaras, Shear Stress Turbulence (SST) k-? model, RNG k-? with enhanced wall treatment are used to capture turbulent boundary layer along the hydrofoil surface. The results predicted by these models are compared with each other. The cavitating study first presented an unsteady behavior of the partial cavity attached to the foil. Then, an analysis of a supercavitating condition is performed. The predicted results show good agreement with results published by other researchers.DOI: 10.3329/jname.v7i2.5270
Mechanical properties and corrosion resistance of normal strength and high strength steels in chloride solution
Authors: Rahbar Ranji Ahmad , Zakeri Amir Hamed
Published: May 2011

The corrosion resistance (weight loss) and mechanical properties (i.e. yield strength, ultimate strength and elongation) for three carbon steels, normal strength and high strength steels using tension test are investigated. The specimens are kept in chloride solution (20% NaCl) up to 240 hours. At every 48 hours, thickness and weight loss is measured and tension test is carried out. It was found that the susceptibility of the steels to corrosion based on their weight loss were identical prior to 144 hours, after that is accelerated for high strength steel. In addition, it was found that manganese (Mn) has reduced corrosion rate at early stage of corrosion. The change in mechanical properties by corrosion for all steels are the same, and ultimate strength is reduced, which for limit state design of aged structure should be taken into account.DOI: 10.3329/jname.v7i2.5309
Effect of Reynolds and Prandtl Numbers on Mixed Convection in an Obstructed Vented Cavity
Authors: Rahman M. M. , Billah M. M. , Alim M. A.
Published: May 2011

A numerical investigation is conducted to analyze the steady flow and thermal fields as well as heat transfer characteristics in a vented square cavity with a built-in heat conducting horizontal solid circular obstruction. Hydrodynamic behavior, thermal characteristics and heat transfer results are obtained by solving the couple of Navier-Stokes and energy equations by using a weighted residuals Finite element method. The computation was made for different Reynolds number, Prandtl number ranging from 50 to 200 and from 0.71 to 7.1 at the three different convective regimes. Three different regimes are observed with increasing Ri: forced convection (with negligible free convection), mixed convection (comparable free and forced convection) and free convection dominated region (with higher free convection). The results are presented to show the effects of the Reynolds number, Prandtl number on flow pattern, thermal field and heat transfer characteristics at the three convective regimes. It is found that the flow and thermal field strongly depend on the Reynolds number, Prandtl number as well as Richardson number. As the Reynolds number and Prandtl number increase, the heat transfer rate increases but average fluid temperature in the cavity and temperature at the cylinder center decrease at the three convective regimes.Keywords: Mixed convection; Finite element method; Obstructed vented cavity; Prandtl number.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i2.4344                J. Sci. Res. 3 (2), 271-281 (2011)
Biotransformation of 11-ketoprogesterone by Filamentous Fungus, Fusarium lini
Authors: Al-Maruf M. A. , Khan N. T. , Saki M. A. A. , Choudhary M. I. , Ali M. U. , Islam M. A.
Published: May 2011

Microbial transformation of 11-ketoprogesterone (1) by the filamentous fungi Fusarium lini was investigated. Biotransformation of 1 with F. lini resulted in the production of ten oxidative metabolites (2-11). Structures of these metabolites were deduced by spectroscopic analysis and seven of them, 5-11, were found to be new metabolites.Keywords: 11-Ketoprogesterone; Steroid; Microbial transformation; Hydroxylation; Filamentous fungi; Fusarium lini.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi:10.3329/jsr.v2i2.6221                J. Sci. Res. 3 (2), 347-356 (2011)
On Study of Vertex Labeling of Graph Operations
Authors: Rajan M. A. , Kembhavimath N. M. , Lokesha V.
Published: May 2011

Vertices of the graphs are labeled from the set of natural numbers from 1 to the order of the given graph. Vertex adjacency label set (AVLS) is the set of ordered pair of vertices and its corresponding label of the graph. A notion of vertex adjacency label number (VALN) is introduced in this paper. For each VLS, VLN of graph is the sum of labels of all the adjacent pairs of the vertices of the graph. is the maximum number among all the VALNs of the  different labeling of the graph and the corresponding VALS is defined as maximal vertex  adjacency label set . In this paper  for different graph operations are discussed. Keywords: Subdivision; Graph labeling; Direct sum; Direct product.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i26222                  J. Sci. Res. 3 (2), 291-301 (2011)
Production of 128I Atoms through 127I (n,γ) 128I Reactions in some Solid Iodocompounds using an (241Am-Be) Neutron Source
Authors: Zaman M. R. , Hossain M. A. , Sarkar M. J. A.
Published: May 2011

Present work reports the production of 128I atoms through 127I (n,g) 128I reactions in six iodine containing compounds (viz. NaI, NaIO3, NaIO4, KI, KIO3 and KIO4) in solid state. An  241Am-Be neutron source has been used for the production of 128 I atoms. The radioactivities produced have been measured by a thin end-window G.M. Counter. The irradiation time and counting geometry were constant throughout the present sets of experiments. Results obtained have been analyzed through time-decay analyses. From the decay curves, the half life of 128I  has been estimated ~25 minutes. The average zero time activities of 128I from three independent measurements in each of NaI, NaIO3.H2O, NaIO4, KI, KIO3 and KIO4 target, have been found 116 ± 2, 92 ± 4, 88 ± 6, 102 ± 6, 98 ± 1 and 93 ± 5 cpm respectively. It is interesting to note that the activities show a decreasing trend while passing through either from NaI to NaIO4 or from KI to KIO4. Results are attributed to the quantity of 128I produced in a specified volume element and, self absorption and self scattering of radiations within the target compounds studied.  Keywords: Iodocompounds; 128I; 241Am-Be neutron source; Chemical effects of nuclear transformation.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i2.6385                 J. Sci. Res. 3 (2), 357-366 (2011)
Phytochemical and Hypoglycemic Evaluation of Alangium Salviifolium Root Extract
Authors: A. Ahad H. , S Padmaja B. , P Yesupadam , P Guruprakash , M Sravanthi , P Ramyasree
Published: May 2011

.The main purpose of present study was to perform phytochemical screening and explore the anti-hyperglycaemic properties of Alangium salvifolium root extract in normal and alloxan induced diabetic rats. A. salvifolium root gave maximum extractive values of 6.4 % w/w with Ethanol and other parameters were within limits. The extract gave positive tests for phytosterols, triterpenes, flavonoids, carbohydrates and alkaloids. The ethanolic extract of A. salvifolium was found to be nearly as potent as tolbutamide in decreasing the blood glucose levels in normal fasting rats. In normal control group the percent reduction in blood glucose indicated that the extract is fast acting. The extract showed significant decrease in blood glucose, when compared with tolbutamide. The evaluated blood glucose levels in alloxan induced diabetic rats were significantly decreased up to 24th h compared to tolbutamide. A single oral administration of alcoholic extract at doses 100, 250 and 500 mg per kg produced a significant blood glucose reduction in a dose dependent manner in normal and diabetic rats. These data confirm the hypoglycaemic and anti-hyperglycaemic effect of alcoholic extract of A. salvifolium root in normal and diabetic rats respectively when compared with standard drug tolbutamide.Keywords: Alangium salvifolium; Ethanolic extract; Alloxan induced; Hypoglycaemic action.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i2.7047                J. Sci. Res. 3 (2), 393-402 (2011)
Eigen Spectra for q-Deformed Hyperbolic Scarf Potential Including a Coulomb-like Tensor Interaction
Authors: Eshghi M. , Mehraban H.
Published: May 2011

We study the Dirac equation for the q-deformed hyperbolic Scarf potential including a coulomb-like tensor potential under the spin symmetry. The parametric generalization of the Nikiforov-Uvarov method is used to obtain the energy eigenvalues equation and the unnormalized wave functins.Keywords: Dirac equation; q-deformed hyperbolic Scarf; Spin symmetry; Tensor coupling.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i2.7295                 J. Sci. Res. 3 (2), 239-247 (2011)
Molecular systematics of the parasitic genus Conopholis (Orobanchaceae) inferred from plastid and nuclear sequences
Authors: Rodrigues Anuar G. , Colwell Alison E.L. , Stefanović Saša
Published: May 2011

• Premise of the study: Little is known of the evolutionary relationships within Conopholis, a small holoparasitic genus belonging to the broomrape family. Presently, Conopholis is described as having two species, C. americana and C. alpina. This classification is based on a combination of presence/absence of morphological characters along with a number of quantitative traits. We assessed the relationships among populations and species of this genus to determine whether the present taxonomic hypothesis is reflected in molecular phylogenies.

• Methods: We conducted the first phylogenetic study of Conopholis using plastid (trnfM‐E intergenic spacer and clpP gene/introns) and nuclear (PHYA intron 1) sequences from a wide taxonomic sampling covering its entire geographical range in North America. Analyses were carried out using a variety of phylogenetic inference approaches.

• Key results: Reciprocal monophyly between the two traditionally accepted species has not yet been achieved. Instead, three distinct genetic clusters were recovered. Conopholis alpina is clearly paraphyletic and shows evidence of belonging to at least two distinct lineages. Specimens found in Costa Rica and Panama form a distinct group from those located in northern Mexico and the southwestern United States. The monophyly of C. americana was also not recovered; however, the possibility of it being monophyletic could not be rejected with confidence.

• Conclusions: These analyses recovered three distinct lineages indicating that there could be a minimum of three species within the genus. A reevaluation of morphological features within Conopholis may reveal shared features that could further corroborate our molecular findings.
Identification and characterization of 12 microsatellite loci in Cnidium dubium (Apiaceae) using next‐generation sequencing
Authors: Michalczyk Inga M. , Schumacher Claudia , Mengel Christina , Leyer Ilona , Liepelt Sascha
Published: May 2011

• Premise of the study: We present a set of 12 polymorphic nuclear microsatellite loci, identified for the first time within the herbaceous plant species Cnidium dubium (Schkuhr) Thell. using next‐generation sequencing.

• Methods and Results: To characterize these loci, 40 plants were analyzed genetically. The number of alleles ranged from 2 to 23, with an average of 8.3 alleles per locus. Mean observed and expected heterozygosities ranged from 0.25 to 0.95 and 0.30 to 0.94, respectively.

• Conclusions: All 12 nuclear microsatellite loci showed scorable and polymorphic fragments after polymerase chain reaction. The new marker set can be used for future studies of genetic diversity and differentiation as well as estimation of gene flow and spatial genetic structures.
Microsatellite markers for the high Andean species Schizanthus hookeri and S. grahamii (Solanaceae)
Authors: Pérez Fernanda , Spencer Patricio , Cienfuegos Alejandra , Suárez Lorena
Published: May 2011

• Premise of the study: Seven microsatellite loci were developed for the two closely related high Andean species Schizanthus hookeri and S. grahamii. These species are annual to biannual herbs with zygomorphic and showy flowers that differ in floral morphology, autonomous selfing capacity, and in the identities of major flower visitors.

• Methods and Results: Polymorphisms were evaluated in a total of 45 plants, including individuals from two populations of S. grahamii and one population of S. hookeri. The number of alleles per locus ranged from two to nine in each population. We also tested these loci for cross‐amplification in another seven species of the genus. Four primer pairs amplified in these seven species.

• Conclusions: Characterized microsatellites are conserved in the closely related species S. hookeri and S. grahamii, and they have enough polymorphism to be used in future studies of their mating systems and genetic structure.
« Sur le bord du monde »
Authors: Di Rocco Vincent
Published: May 2011

Résumé À travers le cas de Émétério, jeune schizophrène photographe de talent, l’auteur souhaite montrer l’importance des liens entre les impasses de la subjectivation du processus adolescent et l’émergence d’états psychotiques au sortir de cette période de l’existence. Dans le cadre psychothérapique, le travail artistique et le travail du rêve se rejoignent dans une tentative de représentation réflexive des processus psychiques en échec. L’analyse clinique porte plus spécifiquement sur la dialectique des processus dits « limites », oscillant entre création et effacement des limites différenciatrices en lien avec les hypothèses de G. Lavallée sur la rupture de la boucle réflexive contenante et subjectivante de la vision. L’auteur fait aussi l’hypothèse que les destins de ce travail de construction et de déconstruction suscitent un intérêt particulier des adultes à propos des rapports que tisse l’adolescent avec la création et la mort.
Quelle place pour les apprenants dans la compréhension de la problématique de l'illettrisme ?
Authors: Vinérier Anne
Published: May 2011

Résumé Peut-on considérer que des apprenants en réapprentissage de savoirs de base puissent participer à la construction d’un savoir sur la problématique de l’illettrisme ? Peut-on considérer qu’ils puissent être force de propositions ? Une question de fond sur la façon de poser des problèmes de société avec ou sans les personnes concernées… Cet article présente une démarche qui situe des apprenants acteurs impliqués dans la création du mouvement de la Chaîne des Savoirs pour défendre le droit à la formation pour tous, dans une méthodologie qui associe formation, recherche et action.
Gain Attention, Enhance Memory, and Improve Learning with Brain-Based Strategies
Authors: Restaino Rusti
Published: May 2011

Applying what we know about brain function to both traditional and online teaching is easy. This column discusses brain function and “tips” for structuring teaching based on it.