bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiation-Induced Schwannomas
Authors: Rubinstein Abraham B. , Reichenthal Eli , Borohov Haim 
Published: May 2010

ABSTRACT
The histopathology and clinical course of three patients with schwannomas of the brain and high cervical cord after therapeutic irradiation for intracranial malignancy and for ringworm of the scalp are described. Earlier reports in the literature indicated that radiation of the scalp may induce tumors in the head and neck. It is therefore suggested that therapeutic irradiation in these instances was a causative factor in the genesis of these tumors.
Electro-Osmotic Chemical Treatments: Effects of Ca2+ Concentration on the Mechanical Strength and pH of Kaolin
Authors: Chang Hao-Wei , Krishna Paramesamangalam Gopi , Chien Shao Chi , Ou Chang Yu , Wang Ming Kuang 
Published: May 2010

AbstractElectro-osmotic chemical treatment is an innovative method to improve the strength of soft clays for geotechnical engineering purposes; the effectiveness of the treatment may be related to treatment time, the concentration of the solutions injected, and to variation of pH in the clay. The objective of this study was to investigate the relationship between the above-mentioned factors and the improvement in strength when calcium chloride solution was used as an injection material. A series of tests was carried out by injecting different concentrations of calcium chloride solution into a kaolin suspension, for different treatment times, during electro-osmosis. After the tests, the pH, cone resistance, water content, and concentration of Ca2+ in the kaolin at different locations were measured and analyzed. The results show that the concentration of Ca2+ in the kaolin, the pH, and the strength were increased near the cathode with increases in concentration of CaCl2 and treatment time. An insignificant increase in strength, due to ion exchange over the entire specimen, for short treatment times of 2 to 24 h, was observed because of a small increase in concentration of Ca2+ and in pH. During long-term treatment (120 h), a considerable increase in concentration of Ca2+ (137.0 mg/g) and pH (pH = 10) was observed near the cathode. This led to a pozzolanic reaction, which in turn caused a significant increase in the mechanical strength of the kaolin.
A Mössbauer Spectroscopic Study of Aluminum- and Iron-Pillared Clay Minerals
Authors: Aouad Amina , Anastácio Alexandre S. , Bergaya Faïza , Stucki Joseph W. 
Published: May 2010

AbstractThe placement of metal oxide pillars between clay mineral layers modifies their physical-chemical properties, including surface area, acidity, and catalytic activity. Aluminum is the most commonly used pillar cation, but the use of Fe offers a distinct opportunity to expand the range of catalytic behavior. The purpose of this study was to prepare Fe-pillared Laponite and montmorillonite and to characterize the resulting Fe phase(s). Laponite or montmorillonite suspension was mixed with different pillaring solutions containing Al oligomer and/or Fe oligomer with Fe:(Al+Fe) percent ratios ranging from 0 to 100%. The Al oligomer was obtained by hydrolysis of A1C13·6H2O with NaOH at pH 4.4 and the Fe oligomer was prepared by FeCl3 hydrolysis with Na2CO3 at pH 2.2. The pillared clay was obtained by adding the oligomer to the clay suspension, then heating to 300°C for 3 h. The Fe oligomer and the pillared clay minerals were characterized by variable-temperature Mössbauer spectroscopy, X-ray powder diffraction, and chemical analysis. The unheated Fe oligomer was akaganeite, an Fe oxyhydroxide phase. Heating the Fe oligomer to 300°C transformed the akaganeite to hematite, but heating it in the presence of the clay protected it, at least partially, from this transformation, creating instead a phase which resembled a more poorly ordered akaganeite or a mixture of akaganeite and poorly ordered hematite. Mixing of Al and Fe oligomers in the pillaring solution had no effect on the magnetic hyperfine field of the Fe pillars, indicating that Al forms separate pillars rather than substituting for Fe in the pillar. A small fraction (4%) of the Fe pillar resisted reductive dissolution by citrate-bicarbonate-dithionite.
Density Functional Theory (DFT) Study of the Hydration Steps of Na+/Mg2+/Ca2+/Sr2+/Ba2+-Exchanged Montmorillonites
Authors: Berghout Abid , Tunega Daniel , Zaoui Ali 
Published: May 2010

AbstractTheoretical models of the mechanical properties of hydrated smectites, saturated with a variety of cations, are of much value in determining the potential for their use in various applications, including clay-polymer nanocomposites, but the development of such models is still in its infancy. The purpose of this study was to calculate the effects of divalent cations on the structural and mechanical elasticity of montmorillonite under different degrees of hydration. A theoretical study of the swelling and hydration behavior of montmorillonite was, therefore, undertaken using density functional theory (DFT) to investigate the basal spacing behavior of the homoionic montmorillonite with varying amounts of water in the interlayer space. The effect of the degree of the hydration of divalent interlayer cations (Mg2+/Ca2+/ Sr2+/Ba2+) on the structure expansion of the interlayer space was analyzed. In addition, the results obtained were compared to calculations performed on the montmorillonite model with a monovalent cation (Na+). The basal spacing (d001) is governed by the size and the degree of hydration of the countercations. The structures containing divalent cations are more compact than structures with monovalent cations. Ba-exchanged montmorillonite was found to have the largest d001 value for any degree of hydration (‘dry,’ one water layer, or two layers). The basal spacings of ‘dry’ montmorillonite exchanged with small cations, Mg2+ and Ca2+, are very similar. In hydrated models, the d001 expansion correlates with the ionic radius of the interlayer cation. The dependence of the total electronic energy on the volume expansion was calculated. From the energetic curves, bulk modulus (B0) was obtained by fitting in order to show how the compliance of the material depends on the type of interlayer cation and on the degree of hydration. With increasing water content in the interlayer space, the bulk modulus decreased, suggesting that the c-axial compression becomes easier with increasing hydration of the clay mineral. The values of the bulk modulus in hydrated systems are less sensitive to the type of the interlayer cation.
Dolocretes and Associated Palygorskite Occurrences in Siliciclastic Red Mudstones of the Sariyer Formation (Middle Miocene), Southeastern Side of the Çanakkale Strait, Turkey
Authors: Kadir Selahattin , Eren Muhsin , Atabey Eşref 
Published: May 2010

AbstractThe origins of dolocrete and associated palygorskite in the Çanakkale region of Turkey have been little studied, but are of fundamental importance for a more complete understanding of the mineralogy of this region. The present study was undertaken in order to narrow this gap. Siliciclastic red mudstones within alluvial-fan deposits of the Middle Miocene Sariyer Formation locally contain dolocretes in various forms (powdery, nodular, and fracture-filling) and scarce matte-brown, authigenic clay lenses. The mineralogical characteristics of dolocrete and authigenic clay lenses were examined using polarized-light microscopy, X-ray diffraction, differential thermal analysis and thermal gravimetry, scanning-electron microscopy, and infrared spectroscopy, as well as by chemical and isotopic methods. These analyses indicate that the dolocretes are indeed predominantly dolomite, coexisting with variable amounts of palygorskite. The authigenic clay lenses are composed mainly of palygorskite. Dolomite appears as euhedral crystals, whereas palygorskite developed authigenically as interwoven fibers on and between resorbed dolomite crystals, rimming euhedral crystals, and as fiber bundles (where dolomite ± magnesite is absent). The stable-isotope values and some petrographic features, such as alveolar texture and dolomite needles, support a pedogenic origin for the dolocretes. In the initial stage, dolomite formed by replacement of siliciclastic red mudstones and/or by precipitation from percolating soil-derived water in a near-surface setting. Subsequently, palygorskite either precipitated on the dolomite crystals from relatively more evaporative water, replaced the host-rock mudstone in the presence of Al + Fe, or formed directly from solution where the Ca/Mg ratio decreased and the Al + Fe increased. In view of the large Cr and Ni contents of the bulk-rock samples, the elements required for the crystallization of dolomite and palygorskite (namely Mg, Ca, Si, Al, and Fe) may have been supplied by weathering of ophiolitic rocks that crop out in the area.
Factors Influencing the Formation and Characteristics of Halloysites or Kaolinites in Granitic and Tuffaceous Saprolites in Hong Kong
Authors: Churchman Gordon Jock , Pontifex Ian Russell , McClure Stuart Gerrand 
Published: May 2010

AbstractThe occurrence of halloysite and/or kaolinite in clay-rich, vein-like zones in saprolites in Hong Kong has provided the opportunity to examine the conditions determining the formation of one kaolin mineral or the other and also the nature of their particles. Clay-rich zones within tuffaceous or granitic saprolites from six different hillside sites have been examined in replicate samples by optical and scanning electron microscopy, X-ray diffraction, and thermal analysis. Kaolin minerals, sometimes together with Mn oxides and Fe oxides/oxyhydroxides, have formed within discontinuities within the altered host rocks. The fabrics of kaolin infills generally indicated several generations of kaolin formation and that shear and deformation have commonly occurred within the infills. The infills were either light or dark in color. Light-colored infills often comprised pure, or nearly pure, halloysite or kaolinite. Dark Mn- and Fe-rich infills all contained kaolinite, while including some halloysite. The very halloysitic, light-colored infills occurred in saprolites in both granite and tuff as long tubular shapes in parallel bunches. The light-colored, very kaolinitic infills occurred in tuff only, in large platy or near-platy shapes within vermiform packets. In dark-colored infills, early kaolin mineral crystallization was limited by impurities from the breakdown of primary minerals leaving dissolved and re-precipitated compounds of Mn and Fe within the infill. Kaolin minerals in infill at all the sites except one are considered to have formed as a result of weathering. The exception comprises white infills in tuff that are composed of extremely small, closely packed particles, suggesting formation by hydrothermal action. Generally, the kaolin minerals have formed by neogenesis out of solution in the discontinuities. Drying, with the formation of Mn and/or Fe oxides/oxyhydroxides, had occurred several times, indicating enhanced drainage. Where drying had occurred, kaolinite had formed. Where indications of drying in infills were absent, halloysite was predominant.
Far-Infrared Study of the Influence of the Octahedral Sheet Composition on the K+-Layer Interactions in Synthetic Phlogopites
Authors: Diaz Magali , Robert Jean-Louis , Schroeder Paul A. , Prost Rene 
Published: May 2010

AbstractFar-infrared (FIR) analysis of synthetic Mg-, Ni-, Co-, and Fe-phlogopites coupled with structural data from X-ray diffraction revealed that the K interlayer environments are directly related to octahedral sheet composition and geometry. The general phlogopite formula, KM32+(Si3Al)O10(OH)2, was varied according to octahedral compositions, where M2+ = Mg2+, Fe2+, Co2+, and Ni2+. Octahedral substitutions have a direct effect on the b lattice parameter, which is related to the tetrahedral-octahedral sheet misfit and manifested by change in the tetrahedral rotation angle (α). The ditrigonal interlayer cavity geometry and the potential for retention of the compensating cations therefore varies according to the ionic size and the types and oxidation state of octahedral cations. These structural features appear as frequency shifts on FIR spectra. When Mg2+ is replaced by a smaller cation, Ni2+, the b parameter decreases and the tetrahedral rotation angle, α, increases, inducing the collapse of the ditrigonal ring. When this happens, the local anisotropy of the interlayer site increases, resulting in every other six out of 12 K-O bonds becoming shorter and the in-plane K-O vibration band shifts slightly to greater wavenumbers. Synthetic phlogopites with octahedral substitutions by cations of larger ionic radii (i.e. Co2+ and Fe2+) exhibit b parameter increases, where in the case of the annite end-member, α decreases to almost 0°. As α decreases, compensating cation sites become more hexagonal like and the nearest K-O bond increases in length. The K-O vibration bands move toward much smaller wavenumbers. Far infrared offers the potential for a new approach to study the retention of interlayer cations in other phyllosilicates and the mechanisms by which they are altered, such as heating or by weathering reactions in the environment.
Enhancement of Dissolution Rates of Amorphous Silica by Interaction with Bovine Serum Albumin at Different pH Conditions
Authors: Kawano Motoharu , Hwang Jinyeon 
Published: May 2010

AbstractProteins and protein-like molecules are abundant in various geochemical environments; they form complexes with mineral surfaces and with dissolved organic matter. To evaluate the effect of proteins on rates of dissolution of minerals, experiments on the dissolution of amorphous silica in solutions containing various concentrations of bovine serum albumin (BSA) were performed in this study. The dissolution experiments were carried out by a batch method using solutions of 0.1 mM NaCl with 0.00, 0.05, 0.1, 0.2, 0.5, and 1.0 mg/mL of BSA at three different pH conditions, 6, 5, and 4. The results of the experiments demonstrated that BSA exhibited strong rate-enhancement effects on the dissolution of amorphous silica and were dependent on BSA concentration and the solution pH. At pH 6, the dissolution rates of amorphous silica appeared to increase successively by ~1.6, 2.2, 2.4, 2.5, and 2.9 times with increasing BSA concentrations of 0.05, 0.1, 0.2, 0.5, and 1.0 mg/mL, respectively. The rates of dissolution increased by greater degrees, ~3.1–5.8 and 4.9–13.0 times at pH 5 and 4, respectively. According to the calculated charge distributions of amino acid residues of the BSA molecule, the dissolution rates of amorphous silica were likely to be enhanced by attractive electrostatic interactions of the positively charged side chains of lysine, arginine, and histidine residues with the negatively charged >SiO− sites on the amorphous silica surface. The negatively charged side chains such as glutamic acid and aspartic acid residues may inhibit the attractive interaction, depending on the degree of deprotonation.
Mountain Pastoralism 1500-2000: An Introduction
Authors: Montero Raquel Gil , Mathieu Jon , Singh Chetan 
Published: May 2010

Abstract
This special issue of Nomadic Peoples presents a collection of articles that give an idea of the continuities and changes of pastoralism in upland areas during the past five centuries. They are the result of a lengthy project on 'Mountain Pastoralism and Modernity' organized by historians from different continents. The following introduction aims to trace the framework of that enterprise. It takes up a few key concepts: mountain pastoralism, history, verticality, intensification and mobility. It then describes the project, outlines the current state of research in the continents concerned, and points to some results and prospects.
Mountain Pastoralism and Spatial Mobility in the South-Peruvian Andes in the Age of State Formation (1880-1969 and Beyond)
Authors: Sendón Pablo F. 
Published: May 2010

Abstract
The process of inclusion of the colonial 'Republic of Indians' into the framework of the Peruvian state involved a series of changes in the Indian's judicial status. This article examines the legal metamorphosis experienced by a shepherd population in Southern Peru, Phinaya, on the basis of both historical and ethnographical information. The aim of the article is to examine the extent to which republican policies designed during the nineteenth and twentieth centuries recognized the existence of shepherd populations in the territory of the nation. It also explores to what extent, if any, the twentieth century policies designed to incorporate these populations within a national territory newly defined by its boundaries took account of their patterns of social organization in relation to one aspect of south Peruvian pastoralism: spatial mobility.
The Lost Mobility: Pastoralism and Modernity in Uttarakhand Himalaya (India)
Authors: Dangwal Dhirendra Datt 
Published: May 2010

Abstract
The Bhotiyas and the Gujars are two well-known communities which practised transhumance in Uttarakhand Himalaya. Restrictions first began to be imposed on their mobility under a new forestry regime, which was introduced in the late nineteenth century. The Bhotiyas, who were itinerant traders, had to face the challenge of new market forces when the hills became better integrated with the lowlands under the colonial economy. For both communities, the practice of transhumance became very difficult as the areas available to them for grazing shrank rapidly in independent India. They were compelled to change their livelihood strategies under the impact of modernization. The Bhotiyas were quick to adopt modern education and take up new jobs, while the Gujars were slower and now find it difficult to adjust to the new situation.
Transformations of High Mountain Pastoral Strategies in the Pamirian Knot
Authors: Kreutzmann Hermann 
Published: May 2010

Abstract
Mountain pastoralism in the Pamirian Knot has been significantly transformed from the nineteenth to the twentieth century. The development path has depended on spheres of influence of dominating powers and affiliation to mighty neighbours and, subsequently, to parties in the Cold War. Significant interventions that led to structural changes can be societal transformations, such as those that happened in the Emirate of Bokhara- Tsarist Russia-Soviet Union-Tajikistan sequence, as well as in the framework of establishing Afghan dominance in Badakhshan, in postrevolutionary interventions in Chinese Xinjiang or in the integration of Karakoram communities in the newly created nation-state of Pakistan.
The Transformation of the Alpine Economy in the Fourteenth to Eighteenth Centuries: Harvesting 'Wild Hay' in the High Mountains
Authors: Blatter Michael 
Published: May 2010

Abstract
By the end of the eighteenth century, in the northern valleys of the Central Alps, the economy was driven by raising cattle and providing dairy products for export. In the Middle Ages, however, subsistence economy based on grain, sheep and goat had become predominant. In this article, the transformation between the fourteenth and the eighteenth centuries is reevaluated by focusing on one aspect of mountain pastoralism: haymaking on remote mountain precipices even beyond the reach of livestock - the so called Wildheuen or harvesting wild hay. Its development coincided with the recovery of the economy of the cities in the plains of northern Italy in the 1660s, illustrating how strongly intertwined both the alpine husbandry and the Italian urban industries were on their path to modernity.
When the Mountain Serves the City: The Production of Cheese and Wool in Eighteenth-Century Bresciano (Italian Alps)
Authors: Mocarelli Luca 
Published: May 2010

Abstract
This article analyses the livestock holdings in the Alps, with a particular focus on the relationship between the city of Brescia and the neighbouring alpine valleys. Two economic activities are studied in more depth: cattle breeding for the production of cheese and sheep farming for the production of wool. In the first case, we observe that the cheese dealers of Brescia managed the production and marketed the final goods, since the cheese was largely exported. In the second case, the business was managed by local farmers who constituted a wealthy social class whose activities went beyond farming and include banking.
The influence of vertical density and velocity distributions on snow avalanche runout
Authors: Keshari Ashok K. , Satapathy Deba P. , Kumar Amod 
Published: May 2010

AbstractA one-dimensional avalanche dynamics model accounting for vertical density and velocity distributions is presented. Mass and momentum flux distribution factors are derived to incorporate the effect of density and velocity variations within the framework of depth-integrated models. Using experiments of avalanche flows on an inclined snow chute at Dhundhi, Manali, India, we conceptualize snow flow rheology as a Voellmy fluid where the distribution of internal shearing is given by a Newtonian fluid (NF) or Criminale–Ericksen–Filbey fluid (CEFF). Then the generalized mass and momentum distribution factors are computed for these two fluid models for different density stratifications. Numerical solutions are obtained using a total variation diminishing Lax–Friedrichs (TVDLF) finite-difference method. The model is validated with the experimental results. We find that the flow features of the chute experiments are simulated well by the model. The velocities and runout distances are obtained for the Voellmy model with both NF and CEFF extensions for various input volumes, and the optimum values of the model parameters, namely, coefficients of dynamic and turbulent friction, are determined.
Statistical downscaling of MM5 model output to better assess avalanche threats
Authors: Srinivasan K. , Kumar Ajay , Verma Jyoti , Ganju Ashwagosha 
Published: May 2010

AbstractIn this study, we use MM5 weather-forecast model output and observed surface weather data from 11 stations in the western Himalaya to develop a statistical downscaling model (SDM) to better predict precipitation, 10 m wind speed and 2 m temperature. The analysis covers three consecutive winters: 2004/05, 2005/06 and 2006/07. The performance of the SDM was assessed using an independent dataset from the 2007/08 winter season. This assessment shows that the SDM technique substantially improves the forecast over specific station locations, which is important for avalanche-threat assessment.
Potential flow models of suspension current air pressure
Authors: Turnbull Barbara , McElwaine Jim N. 
Published: May 2010

AbstractWe present, analyse and discuss air-pressure data from finite-volume chute flows of dry fine snow in air. These experiments have the correct similarity criteria to model powder-snow avalanches and demonstrate the transition from a dense to a suspended flow. We measured the dynamic air pressure at the base of the flow, which features a marked negative pressure peak immediately behind the front. This feature is also seen in observations of natural powder-snow avalanches measured in Russia, Japan and Switzerland in direct numerical simulations of non-Boussinesq suspension flows and in ping-pong ball avalanches. This is evidence for large internal motions and suggests that there is a coherent vortex in the avalanche front. This can result in impact pressures many times larger than those expected from the mean flow velocity. We analyse the external air pressures using three models and show how the geometry and velocity of the flow can be found from this single air-pressure measurement. We also measured flow heights and speeds using image analysis and show that the speed is roughly independent of the slope angle and scales with the release size raised to the power 1/4, as predicted by similarity analysis for pseudo two-dimensional (2-D) flows.