bluuebunny/crossref_metadata_2025 huggingface dataset:
INCREASING ANTITUMOR EFFECTS OF CHEMORADIOTHERAPY BY DRUG EFFLUX INHIBITION WITH ENCAPSULATED ANTI-RLIP-76
Authors: HARADA S. , EHARA S. , ISHII K. , YAMAZAKI H. , MATSUYAMA S. , KAMIYA T. , SAKAI T. , ARAKAWA K. , SATO T. , SERA K. , SAITO Y.
Published: July 2011

Microencapsulated anti-RLIP76 was tested in vivo using C 3 He / J mice to determine the increasing of antitumor effects by chemotherapeutic agent efflux inhibition during chemoradiotherapy. Microcapsules were produced by spraying a mixture of 3.0% hyaluronic acid, 2.0% alginate, 3.0% H 2 O 2, and 0.3 mmol carboplatin onto a mixture of 0.3 mol FeCl 2 and 0.15 mol CaCl 2. Microcapsules were subcutaneously injected into MM46 tumors previously inoculated into the left hind legs of C 3 He / J mice. Subsequent radiotherapy consisted of tumor irradiation with 10 Gy or 20 Gy 60 Co . The antitumor effects of microcapsules were tested by measuring tumor size and monitoring tumor growth. Three types of adverse effects were considered: fuzzy hair, loss of body weight, and mortality. Carboplatin levels were monitored using particle-induced X-ray emission (PIXE) and a micro-PIXE camera. Anti-RLIP76 inhibited the efflux of carboplatin from tumor tissue, which led to an increase in the concentration of carboplatin. Higher carboplatin concentration significantly increased the combined antitumor effect of radiation and chemotherapy. A significant decrease in adverse effects was also observed with microencapsulated anti-RLIP76.
ANALYSIS OF THE LETHAL EFFECTS OF LOW-DOSE RADIATION ON GLIOMA CELLS: RELATIONSHIP OF THE BYSTANDER EFFECT AND METAL ELEMENTS
Authors: WADA SEIICHI , SUDO MAUKO , TAMURA SAKIKO , KAKIZAKI TAKEHIKO , ITO NOBUHIKO , SERA KOICHIRO
Published: July 2011

Investigation of the radiation-induced bystander effect plays an important role in the understanding of the mechanisms of radiation response after low-dose irradiation. Sphingomyelinase (SMase) was activated by radiation and required the metal element for its activation. For further elucidation of the bystander effect, we investigated the relationship between its induction by acid SMase and a factor secreted from the irradiated tumor cells. In the cell culture medium transfer experiment after irradiation at a dose of 0.1 Gy , cell death was induced in non-irradiated cells. However, when cells received prior treatment with SMase inhibitor, cell death was not induced. When fluctuations in the activation of SMase and metal elements were detected, both intracellularly and extracellularly after irradiation, an increase in SMase activity and Zn concentration occurred within the cells at 5 min and outside of the cells at 15 min after irradiation. This increase in zinc concentration at 15 min after irradiation was suppressed by treatment with SMase inhibitor. These results suggest that activation of SMase, which is related to the bystander effect, is dependent on zinc.
CHEMICAL SPECIATION OF CHLORINE PRESENT IN PARTICULATE COMBUSTION PRODUCTS OF ORGANIC CHLORINE COMPOUNDS BY EMPLOYING HIGH-RESOLUTION PIXE ANALYSIS
Authors: WONGLEE S. , FUKUDA H. , HASEGAWA J. , OGURI Y.
Published: July 2011

The chemical speciation of chlorine ( Cl ) in particulate matter samples produced by the laboratory burning of organic Cl compounds was tested by employing the high-resolution measurement of K β X-rays based on a wavelength-dispersive proton-induced X-ray emission (WD-PIXE) technique. Targets for proton irradiation were prepared by depositing particulate burning products on aluminum foils placed on a simple barrel burner. Standard inorganic ( NaCl , MgCl 2, CaCl 2, NH 4 Cl , and AlCl 3) and organic (polyvinyl chloride and polyvinylidene chloride) Cl compounds were prepared for spectral comparison. We found that the Cl - K β1 peak energies for these organic compounds are higher by approximately 1 eV than those for inorganic compounds. For burning products of these organic compounds, the peak energies were found to be located between those for organic and inorganic compounds. This result indicates that the organic Cl compounds were decomposed to smaller molecules during the burning process but these fragments still existed in the organic form.
STUDYING THE BASIN OF CONVERGENCE OF METHODS FOR COMPUTING PERIODIC ORBITS
Authors: EPITROPAKIS MICHAEL G. , VRAHATIS MICHAEL N.
Published: July 2011

Starting from the well-known Newton's fractal which is formed by the basin of convergence of Newton's method applied to a cubic equation in one variable in the field ℂ, we were able to find methods for which the corresponding basins of convergence do not exhibit a fractal-like structure. Using this approach we are able to distinguish reliable and robust methods for tackling a specific problem. Also, our approach is illustrated here for methods for computing periodic orbits of nonlinear mappings as well as for fixed points of the Poincaré map on a surface of section.
WAVE INTERACTIONS IN LOCALIZING MEDIA — A COIN WITH MANY FACES
Authors: BODYFELT J. D. , LAPTYEVA T. V. , GLIGORIC G. , KRIMER D. O. , SKOKOS Ch. , FLACH S.
Published: July 2011

A variety of heterogeneous potentials are capable of localizing linear noninteracting waves. In this work, we review different examples of heterogeneous localizing potentials which were realized in experiments. We then discuss the impact of nonlinearity induced by wave interactions, in particular, its destructive effect on the localizing properties of the heterogeneous potentials.
KAM TORI AND ABSENCE OF DIFFUSION OF A WAVE-PACKET IN THE 1D RANDOM DNLS MODEL
Authors: AUBRY S.
Published: July 2011

When nonlinearity is added to an infinite system with purely discrete linear spectrum, Anderson modes become coupled with one another by terms of higher order than linear, allowing energy exchange between them. It is generally believed, on the basis of numerical simulations in such systems, that any initial wave-packet with finite energy spreads down chaotically to zero amplitude with second moment diverging as a power law of time, slower than standard diffusion (subdiffusion). We present results which suggest that the interpretation of spreading cannot be described as initially believed and that new questions arise and still remain opened. We show that an initially localized wave-packet with finite norm may generate two kinds of trajectories both obtained with nonvanishing probability.

The first kind consists of KAM trajectories which are recurrent and do not spread. Empirical investigations suggest that KAM theory may still hold in infinite systems under two conditions: (1) the linearized spectrum is purely discrete, (2) the considered solutions are square summable and not too large in amplitude. We check numerically that in appropriate regions of the parameter space, indeed many initial conditions can be found with finite probability that generate (nonspreading) infinite dimension tori (almost periodic solutions) in a fat Cantor set in (projected) phase space.

The second kind consists of trajectories which look initially chaotic and often spread over long times. We first rigorously prove that initial chaos does not necessarily imply complete spreading e.g. for large norm initial wave-packet. Otherwise, in some modified models, no spreading at all is proven to be possible, despite the presence of initial chaos in contradiction with early beliefs. The nature of the limit state is still unknown.

However, we attempt to present empirical arguments suggesting that if a trajectory starts chaotically spreading, there will necessarily exist (generally large) critical spreading distances that depend on the disorder realization where the trajectory will be sticking to a dense set of KAM tori. This effect should induce drastic slowing down of the spreading which could be viewed as "inverse Arnold diffusion" since the trajectory approaches KAM tori regions instead of leaving them. We suggest that this effect should self-organize the chaotic behavior and that at long time, the wave-packet might not be spread down to zero, but could have a limit profile with marginal chaos (with singular continuous spectrum), despite a long spatial tail. Further analytical and numerical investigations are required.
NONLINEAR MAGNETOINDUCTIVE TRANSMISSION LINES
Authors: LAZARIDES NIKOS , PALTOGLOU VASSILIS , TSIRONIS G. P.
Published: July 2011

Power transmission in one-dimensional nonlinear magnetic metamaterials driven at one end is investigated numerically and analytically in a wide frequency range. The nonlinear magnetic metamaterials are composed of varactor-loaded split-ring resonators which are coupled magnetically through their mutual inductances, forming thus a magnetoiductive transmission line. In the linear limit, significant power transmission along the array only appears for frequencies inside the linear magnetoinductive wave band. We present analytical, closed form solutions for the magnetoinductive waves transmitting the power in this regime, and their discrete frequency dispersion. When nonlinearity is important, more frequency bands with significant power transmission along the array may appear. In the equivalent circuit picture, the nonlinear magnetoiductive transmission line driven at one end by a relatively weak electromotive force, can be modeled by coupled resistive-inductive-capacitive (RLC) circuits with voltage-dependent capacitance. Extended numerical simulations reveal that power transmission along the array is also possible in other than the linear frequency bands, which are located close to the nonlinear resonances of a single nonlinear RLC circuit. Moreover, the effectiveness of power transmission for driving frequencies in the nonlinear bands is comparable to that in the linear band. Power transmission in the nonlinear bands occurs through the linear modes of the system, and it is closely related to the instability of a mode that is localized at the driven site.
ON THE BIFURCATION AND CONTINUATION OF PERIODIC ORBITS IN THE THREE BODY PROBLEM
Authors: ANTONIADOU K. I. , VOYATZIS G. , KOTOULAS T.
Published: July 2011

We consider the planar three body problem of planetary type and we study the generation and continuation of periodic orbits and mainly of asymmetric periodic orbits. Asymmetric orbits exist in the restricted circular three body problem only in particular resonances called "asymmetric resonances". However, numerical studies showed that in the general three body problem, asymmetric orbits may exist not only for asymmetric resonances, but for other kinds, too. In this work, we show the existence of asymmetric periodic orbits in the elliptic restricted problem. These families of periodic orbits continue existing and clarify the origin of many asymmetric periodic orbits in the general problem. Also, we illustrate how the families of periodic orbits of the restricted circular problem and those of the elliptic one join smoothly and form families in the general problem, verifying in this way the scenario first described by Bozis and Hadjidemetriou.
DIFFUSION OF CHAOTIC ORBITS IN BARRED SPIRAL GALAXIES
Authors: HARSOULA M. , KALAPOTHARAKOS C. , CONTOPOULOS G.
Published: July 2011

We study the diffusion of chaotic orbits in an N-body model simulating a barred spiral galaxy. Chaotic orbits with initial conditions outside corotation support the spiral structure of the galaxy due to the phenomenon of stickiness close and along the unstable asymptotic manifolds of the unstable periodic orbits. These orbits are diffused outwards after about 13 rotations of the bar. During this time, the spiral structure is clearly visible and then it fades out gradually. The diffusion time for the majority of the chaotic orbits with initial conditions inside corotation is much longer than the age of the Universe. These orbits support mainly the outer parts of the bar. However, a part of the chaotic orbits inside corotation are diffused outwards fast and support the spiral structure.
THE THREE TROJAN PROBLEM
Authors: DVORAK RUDOLF , BAZSÓ ÁKOS
Published: July 2011

This paper is devoted to the stability study of three Trojan planets around a central star of 1 M Sun in a distance of 1 AU. In an earlier study, the stability of this coorbital configuration was computed if the mutual angular separation is 47.4° [Salo & Yoder, 1988]. We investigated by using numerical integrations the largeness of the stable region around these stable equilibrium points, depending on the mass parameter and the distances of the three planets. It turned out that even initial deviations in semimajor axis in the order of 5% can lead to very stable orbits. Also differences in the initial angular distance from the equilibrium points up to 70° do not mean that the orbits will be unstable. But the extensions in semimajor axis and angles depend sensitively on the masses involved, which were given the same values for our investigations in a first step. Test computations for different masses of the three planets involved show that they may be quite large without destroying the stability.
RELAXATION OF SPHERICAL SYSTEMS WITH LONG-RANGE INTERACTIONS: A NUMERICAL INVESTIGATION
Authors: DI CINTIO PIERFRANCESCO , CIOTTI LUCA
Published: July 2011

The process of relaxation of a system of particles interacting with long-range forces is relevant to many areas of physics. For obvious reasons, in Stellar Dynamics much attention has been paid to the case of r-2force law. However, recently the interest in alternative gravities has emerged, and significant differences with respect to Newtonian gravity have been found in relaxation phenomena. Here we begin to explore this matter further, by using a numerical model of spherical shells interacting with an r-αforce law obeying the superposition principle. We find that the virialization and phase-mixing times depend on the exponent α, with small values of α corresponding to longer relaxation times, similarly to what happens when comparing for N-body simulations in classical gravity and in Modified Newtonian Dynamics.
WEAK CHAOS DETECTION IN THE FERMI–PASTA–ULAM-α SYSTEM USING q-GAUSSIAN STATISTICS
Authors: ANTONOPOULOS CHRIS G. , CHRISTODOULIDI HELEN
Published: July 2011

We study numerically statistical distributions of sums of orbit coordinates, viewed as independent random variables in the spirit of the Central Limit Theorem, in weakly chaotic regimes associated with the excitation of the first (k = 1) and last (k = N) linear normal modes of the Fermi–Pasta–Ulam-α system under fixed boundary conditions. We show that at low energies (E = 0.19), when k = 1 linear mode is excited, chaotic diffusion occurs characterized by distributions that are well approximated for long times (t > 109) by a q-Gaussian Quasi-Stationary State (QSS) with q ≈ 1.4. On the other hand, when k = N mode is excited at the same energy, diffusive phenomena are absent and the motion is quasi-periodic. In fact, as the energy increases to E = 0.3, the distributions in the former case pass through shorterq-Gaussian states and tend rapidly to a Gaussian (i.e. q → 1) where equipartition sets in, while in the latter we need to reach up to E = 4 to see a sudden transition to Gaussian statistics, without any passage through an intermediate QSS. This may be explained by different energy localization properties and recurrence phenomena in the two cases, supporting the view that when the energy is placed in the first mode weak chaos and "sticky" dynamics lead to a more gradual process of energy sharing, while strong chaos and equipartition appear abruptly when only the last mode is initially excited.
MATHEMATICAL EXAMPLES OF SPACE-TIME PHASES
Authors: DIAKONOVA M. , MACKAY R. S.
Published: July 2011

The space-time phases of a complex dynamic system are the probability distributions for state as a function of space and time which arise by evolving initial probability distributions from the distant past. Toom proved important results about space-time phases for a class of majority voter probabilistic cellular automata (PCA). Here, variants of the majority voter PCA are presented which are proved to exhibit a variety of types of space-time phase. These examples are expected to serve as useful steps on the way to a general theory of space-time phases.
THE STRUCTURE AND EVOLUTION OF CONFINED TORI NEAR A HAMILTONIAN HOPF BIFURCATION
Authors: KATSANIKAS M. , PATSIS P. A. , CONTOPOULOS G.
Published: July 2011

We study the orbital behavior at the neighborhood of complex unstable periodic orbits in a 3D autonomous Hamiltonian system of galactic type. At a transition of a family of periodic orbits from stability to complex instability (also known as Hamiltonian Hopf Bifurcation) the four eigenvalues of the stable periodic orbits move out of the unit circle. Then the periodic orbits become complex unstable. In this paper, we first integrate initial conditions close to the ones of a complex unstable periodic orbit, which is close to the transition point. Then, we plot the consequents of the corresponding orbit in a 4D surface of section. To visualize this surface of section we use the method of color and rotation [Patsis & Zachilas, 1994]. We find that the consequents are contained in 2D "confined tori". Then, we investigate the structure of the phase space in the neighborhood of complex unstable periodic orbits, which are further away from the transition point. In these cases we observe clouds of points in the 4D surfaces of section. The transition between the two types of orbital behavior is abrupt.
TORUS BIFURCATIONS IN MULTILEVEL CONVERTER SYSTEMS
Authors: ZHUSUBALIYEV ZHANYBAI T. , MOSEKILDE ERIK , YANOCHKINA OLGA O.
Published: July 2011

This paper considers the processes of torus formation and reconstruction through smooth and nonsmooth bifurcations in a pulse-width modulated DC/DC converter with multilevel control. When operating in a regime of high corrector gain, converters of this type can generate structures of stable tori embedded one into the other and with their basins of attraction delineated by intervening repelling tori. The paper illustrates the coexistence of three stable tori with different resonance behaviors and shows how reconstruction of these tori takes place across the borders of different dynamical regimes. The paper also demonstrates how pairs of attracting and repelling tori emerge through border-collision torus-birth and border-collision torus-fold bifurcations.
PARALLEL NUMERICAL METHODS FOR THE SOLUTION OF NONLINEAR PARABOLIC SYSTEMS
Authors: SFYRAKIS CHRYSOVALANTIS A.
Published: July 2011

Due to the considerable complexity involved in the numerical solution of problems of phase change materials, the development of fast parallel algorithms to solve them is very useful. This large complexity can be reduced by developing faster methods for solving, and suitably modifying programming techniques. We consider the phase field model of the system of p.d.e's [Formula: see text] where ϕ = ϕ(x, y, t) is the phase indicator function, θ = arctan (ϕy/ϕx), u = u(x, y, t) is the temperature, q, p and f are given scalar functions. This system describes the evolution of phase and temperature in a two-phase medium, and is posed for t≥0 on a rectangle in the x, y plane with appropriate boundary and initial conditions. We solve the system using two finite difference methods. The first method is based on the explicit Euler scheme for the first equation and the Crank–Nicolson–ADI method for the second. The other method uses for both equations the Crank–Nicolson–ADI scheme. We show results of relevant numerical experiments, compare the errors of the two methods, and compare their speed-up when we implement them using parallel processors. Comparisons between the methods and for each one separately are given, and furthermore useful conclusions concerning the number of nodes and the speed of executing the methods in one, two or four processors are also developed.
WHY HIGH PARTICIPATORY IDEALS FAIL IN PRACTICE: A BOTTOM-UP APPROACH TO PUBLIC NONPARTICIPATION IN EIA
Authors: Wiklund Hans
Published: July 2011

This paper explores the uninvestigated phenomenon of citizens' reasons for nonparticipation in EIA. By adopting a bottom-up approach, based on the assumption that citizens are rational actors who are able to provide reasons for their choice to participate or not to participate, it complements traditional public participation research focusing on structural barriers to and socio-economic predictors of participation. The reasons citizens provide for nonparticipation are described and it is discussed how the design and management of public participation schemes can be improved to better meet the high participatory ideals of EIA expressed by professionals and academics in standards of good practice.
CONFRONTING SEA WITH REAL PLANNING: THE CASE OF FOLLOW-UP IN REGIONAL PLANS AND PROGRAMMES IN SWEDEN
Authors: WALLGREN OSKAR , NILSSON MÅNS , JONSSON DANIEL K. , WIKLUND HANS
Published: July 2011

This paper addresses the problem of "fit" between strategic environmental assessment (SEA) aims and procedures, and the planning context in which SEA is implemented. The paper approaches this problem from a bottom-up perspective, examining existing planning practices, routines and institutions in order to illuminate prospects and barriers for effective SEA implementation. Using empirical results from studies of regional growth programmes and infrastructure plans in Sweden, the study focuses on SEA follow-up and how it can be integrated in existing planning and programming processes. Environmental follow-up is found to be largely absent from existing planning processes. Analytical, organisational and institutional issues are identified as important explanations for the lack of follow-up. Based on this analysis, the paper offers suggestions on how SEA follow-up can become a more effective part of regional planning.
THE INTERRELATIONSHIP OF BIODIVERSITY AND RURAL VIABILITY: SUSTAINABILITY ASSESSMENT, LAND USE SCENARIOS AND NORWEGIAN MOUNTAINS IN A EUROPEAN CONTEXT
Authors: OLSSON E. GUNILLA ALMERED , RÖNNINGEN KATRINA , HANSSEN SUSANNE K. , WEHN SÖLVI
Published: July 2011

The decline and restructuring of agriculture is particularly evident in mountain areas, leading to forest recolonisation on former mountain pastures threatening biodiversity and landscape qualities, and the appeal of the mountain landscape for recreation and tourism. Land use change scenarios based on different agri-environmental incentives were developed for the Jotunheimen mountains, Norway, in collaboration with local stakeholders. Sustainability assessments of the scenarios underscored the connections between landscape, biodiversity and local cultural heritage as the fundament for the development of local enterprises for tourism and niche production. Biodiversity values solely, were not considered to be of major importance by the stakeholders.
Arsenic removal from contaminated water by the Soyatal Formation, Zimapán Mining District, Mexico – a potential low-cost low-tech remediation system
Authors: Ongley Lois K. , Armienta Ma. Aurora , Heggeman Katherine , Lathrop Alison S. , Mango Helen , Miller Wynne , Pickelner Shea
Published: July 2011

The groundwater in Zimapán, Mexico has arsenic concentrations that range from below detection limits to >1 mg l
−1
. Rural residents of the valley need a low-cost, low-tech remediation process to reduce the arsenic concentrations to <50 μg l
−1
, the Mexican drinking water standard.

Laboratory experiments show that the arsenic remediation potential of the Soyatal Formation, an ubiquitous clay-rich limestone, is superior to that of other rocks from the region. Experimentally contaminated water (ECW) was produced by reacting de-ionized water with tailings. The ECW (0.6 mg As l
−1
) was then reacted with various rocks from the Zimapán region. Although all rocks caused a decrease in the aqueous arsenic concentration, the arsenic concentration was below detection limits (<0.030 mg l
−1
) in any ECW that had been reacted with the Soyatal Formation. Other experiments established that a rock:water weight ratio of 1:10 can reduce the aqueous arsenic concentration in native water from 0.5 mg l
−1
to <0.030 mg l
−1
.

The calcareous shale of the Soyatal Formation contains kaolinite and illite. Both minerals are known to adsorb arsenic. The adsorptive characteristics of the Soyatal Formation may provide the basis for an acceptable low-cost low-tech remediation system.
Effects of acidic recharge on groundwater at the St. Kevin Gulch site, Leadville, Colorado
Authors: Paschke Suzanne S. , Harrison Wendy J. , Walton-Day Katherine
Published: July 2011

The acid rock drainage-affected stream of St. Kevin Gulch recharges the Quaternary sand and gravel aquifer of Tennessee Park, near Leadville, Colorado, lowering pH and contributing iron, cadmium, copper, zinc and sulphate to the groundwater system. Dissolved metal mobility is controlled by the seasonal spring runoff as well as oxidation/reduction (redox) reactions in the aquifer. Oxidizing conditions occur in the unconfined portions of the aquifer whilst sulphate-reducing conditions are found down gradient where semi-confined groundwater flow occurs beneath a natural wetland. Iron-reducing conditions occur in the transition from unconfined to semi-confined groundwater flow. Dissolved iron concentrations are low to not detectable in the alluvial fan recharge zone and increase in a down gradient direction. The effects of low-pH, metal-rich recharge are pronounced during low-flow in the fall when there is a defined area of low pH groundwater with elevated concentrations of dissolved zinc, cadmium, copper and sulphate adjacent to St. Kevin Gulch. Dissolved metal and sulphate concentrations in the recharge zone are diluted during spring runoff, although the maximum concentrations of dissolved zinc, cadmium, copper and sulphate occur at selected down gradient locations during high flow. Dissolved zinc, cadmium and copper concentrations are low to not detectable, whereas dissolved iron concentrations are greatest, in groundwater samples from the sulphate-reducing zone. Attenuation of zinc, cadmium and copper beneath the wetland suggests sulphide mineral precipitation is occurring in the semi-confined aquifer, in agreement with previous site investigations and saturation index calculations. Adsorption of dissolved zinc, cadmium and copper onto iron hydroxides is a minor attenuation process due to the low pH of the groundwater system.
Chemical and physical controls on waters discharged from abandoned underground coal mines
Authors: López D. L. , Stoertz M. W.
Published: July 2011

Abandoned up-dip drift mines in high-sulphur coal are a major source of acid mine drainage (AMD) in Appalachia. Studies of mines in the Monday Creek watershed of southeastern Ohio show that mines are recharged by surface runoff into subsidence features that dilate the natural stress-relief fracture system. The direct connection between the ground surface and the mines leads to a rapid response in the hydrograph, with a one- to four-day lag between precipitation and corresponding peak mine discharge. Subsidence occurs in topographic depressions where overburden is presumably relatively thin. Subsidence features drain 20–36% of the surface area. Unsaturated storage appears to be volumetrically insignificant, so that far more recharge occurs than the 5% often assumed for this region. Mine storage can change rapidly due to subsidence recharge. Hydrologically, mines with subsidence features behave like karst systems, with meteoric ‘quickflow’ representing more than 50% of the total flow. Mine discharge concentrations are relatively uniform through time, suggesting either equilibrium controls on chemistry or drainage of a well-mixed pool, or both. Evidence of dilution by high flows is slight. The first high flows after a baseflow period show only a slight increase in concentrations, attributed to flushing of stored reaction products. Loadings (concentrations x flow) depend on volumetric discharge and as a consequence are highly variable. The Eh/pH environment in up-dip drift mines indicates that mine waters are in contact with the atmosphere at least part of the time, unlike a true groundwater. Iron buffering partly controls pH, which clusters around values of 3.6–5.0.
Modelling rock–water interactions in flooded underground coal mines, Northern Appalachian Basin
Authors: Perry Eric F.
Published: July 2011

Inverse geochemical modelling was used to investigate rock–water interactions in flooded underground coal mines in northern Appalachia, USA. In early flooding, Pittsburgh seam mine waters are usually acidic (
c.
 pH 3), with dissolved metals Fe and Al ranging from 10 to >100 mg l
−1
. Within a few decades, however, waters in fully flooded mines usually have pH of about 7 S.U., and alkalinity >300 mg l
−1
CaCO
3
Eq. Eh shifts from oxidizing (
c
. 500 to 700 mv) to reduced (−100 to −200 mv) conditions. Sodium concentrations may increase an order of magnitude; sulphate and iron concentrations may also increase. Water samples were collected from several mine-pools in West Virginia and Pennsylvania. A conceptual model was developed based on quantitative hydrology, mine-pool chemistry, mining conditions and mineralogy. The model was tested with the geochemical code PHREEQC. Simulations included mixing recharge and acid mine waters, precipitation–dissolution reactions involving carbonates, sulphates, oxy-hydroxides and sulphides, and ion adsorption and exchange. Na exchange was a dominant process in all models. Carbonates are orders of magnitude undersaturated in the juvenile mine-pool, but near saturation in the mature mine-pool, suggesting they are a primary source of acid neutralization and alkalinity. The mature mine-pool is simultaneously near equilibrium with iron sulphide, iron carbonate and iron oxy-hydroxide mineral phases. The rapid change in mine-pool water quality has substantial implications for management of these systems. Corresponding author eperry@osmre.gov
Characteristics of sludge produced from passive treatment of mine drainage
Authors: Dempsey Brian A. , Jeon Byong-Hun
Published: July 2011

In the 1994 paper by Brown, Skousen & Renton it was argued that settleability and wet-packing density were the most important physical characteristics of sludge from treatment of mine drainage. These characteristics plus zeta-potential, intrinsic viscosity, specific resistance to filtration, and coefficient of compressibility were determined for several sludge samples from passive treatment sites and for several sludge samples that were prepared in the laboratory. Sludge from passive systems had high packing density, low intrinsic viscosity, low specific resistance to filtration and low coefficient of compressibility compared to sludge that was produced after addition of NaOH.
The interpretation of background variation in regional geochemical surveys – an example from Nunavut, Canada
Authors: Klassen Rodney A.
Published: July 2011

In glaciated terrains, geochemical maps portray bedrock provenance and the integrated effects of glacial processes affecting the distribution, concentration, and partitioning of minerals in sediments. In those maps, indicators of economic mineralization can be difficult to distinguish in the context of natural background, especially at low trace metal concentrations. Sample mineralogy, which can be inferred from lithophile elements, provides a key basis for interpreting sediment provenance and controls on background variation in metal concentrations. In non-carbonate terrain, the principal rock-forming minerals digested by aqua regia are Mg-bearing phyllosilicates, including trioctohedral chlorite, biotite, and phlogopite. Hence, Mg analyses directly reflect the concentrations of those minerals. In a regional geochemical survey of till in Nunavut, strong linear correlations (
r
>0.840,
n
=1842,
p
<0.0001) for Cu and Cr with Mg concentrations indicate Mg-bearing phyllosilicates are the principal metal hosts, and that the metals are bound in mineral lattice structures in direct proportion to Mg. Thus, metal:Mg ratios express geochemical properties of the mineral(s) hosting the metal, and are independent of mineral partitioning among size fractions that results from either glacial or postglacial processes. Ratio maps can be used to establish till provenance and infer aspects of bedrock composition not evident in single-element geochemical maps. Ratio anomalies could indicate metals derived from economic indicators such as sulphide minerals, and metal-rich particulate from anthropogenic sources
.
The effect of sample medium on regolith chemistry over greenstone belts in the northern Eastern Goldfields of Western Australia
Authors: Morris Paul A. , Sanders Andrew J.
Published: July 2011

Gold and Ni concentrations in regolith samples collected from a 16 km
2
grid over Archaean granite–greenstones of the Yilgarn Craton show a strong correlation with lithology and areas of known mineralization, even though most samples are from transported regolith. The influence of sample medium on regolith composition has been assessed by statistical comparison of stream sediment, soil and sheetwash data from four of the largest greenstone belts. Changes in composition according to sample medium can be explained by periodic recharge of stream sediments by fresh or ferruginized bedrock, and different degrees of weathering and sorting during transport, with enrichment or depletion in groups of analytes showing the progressive breakdown of rock-forming minerals. The behaviour of Ti, La, Ce, Cr, Nb and Zr is consistent with the concentration of resistate minerals such as allanite, monazite, chromite, rutile and zircon, due to the combined effects of weathering of less stable phases and mechanical sorting. A statistical assessment shows that comparison of regolith composition between greenstone belts must be made using the same sample medium type. Furthermore, this approach can be used to assess the appropriateness of different sample media in regional geochemical surveys, and to refine analytical programs.
Dispersion of gold and associated elements in the lateritic regolith, Mystery Zone, Mt Percy, Kalgoorlie, Western Australia
Authors: Butt C. R. M.
Published: July 2011

Primary Au mineralization in the Mystery Zone, Mt Percy, occurs in fuchsite–carbonate alteration zones at the contact with felsic porphyries intruding the Hannan’s Lake Serpentinite. The mineralized sequence is concealed beneath an almost complete lateritic regolith over 60 m thick. The regolith consists of 50 m-thick saprolite, which is clay-rich in the top 10 m, plasmic and mottled clays, lateritic residuum (duricrusts and gravels) and pisolitic soils; the surficial horizons contain pedogenic carbonates. Elements occurring with primary Au mineralization are S, Ag, W, As, Sb, Te, K, Rb and, possibly, Ba and Pb, but except for Ag and Te, none has a mineralogical association with Au.

The Au distribution in the regolith is typical for the region, with minor enrichment and lateral dispersion in lateritic residuum, a strong association with pedogenic carbonates, leaching and depletion in the underlying clay-rich horizons and some secondary concentration in the saprolite. Primary and saprolitic Au mineralization is indicated by a broad Au anomaly (100 to >1000 ppb) in the soils and lateritic residuum, and by high concentrations of W (5 to >40 ppm), Sb (7 to >16 ppm) and As (10–200 ppm). High K contents, corresponding to resistant muscovite, give surface expression to the alteration zone. Although Au contents are <100 ppb in the underlying clay-rich horizons, Sb, W and, to a lesser extent, As remain anomalous; similarly, Ba and K contents remain high, indicating the porphyries and alteration zones, respectively.

The porphyries and ultramafic rocks can be discriminated geochemically throughout much of the regolith by relative abundances and ratios of Ti, Zr, Ba and K. However, the lateritic duricrusts overlying the talc–chlorite rocks display abnormal geochemical signatures. They have low Cr contents (<1000 ppm), because primary Cr is present in weatherable chlorite rather than resistant chromite, but are enriched in ‘immobile’ elements (e.g. Zr) derived from the porphyries. The element distribution patterns are products of deep weathering under warm humid conditions in the early Tertiary or earlier, followed by semi-arid conditions that continue to the present. Chemical and physical mobilization of gold was restricted to the surficial lateritic residuum in the humid phases, but depletion and supergene enrichment in the saprolite, and concentration with pedogenic carbonates, are the result of chemical mobility under semi-arid conditions.
Gold mass balance in the regolith, Mystery Zone, Mt Percy, Kalgoorlie, Western Australia
Authors: Sergeev N. B. , Gray D. J.
Published: July 2011

Mineralized rocks at the Mystery Zone gold deposit, Mt Percy, are overlain by an almost complete lateritic regolith over 60 m thick, within which there are significant variations in Au concentration. This includes an apparent Au depletion in the upper saprolite and clay horizons and enrichment in the surficial residuum and soil. Gold leaching up through the regolith has been quantified by mass balance calculations. In the lower saprolite, 55% of the Au has been leached from the porphyries, but Au is essentially immobile in ultramafic rocks. Higher in the regolith, leaching trends are similar over both lithologies, with 74–90% depletion in the clay saprolite, and 84–95% depletion in the plasmic and mottled clay horizons. Within the surficial lateritic residuum and carbonate, Au concentrations increase to significantly greater than bedrock grade, but the calculations show there is little, if any, absolute Au enrichment, compared to the fresh rock.

Silica is progressively depleted through the regolith, with more leaching over fuchsitic ultramafic rocks. Aluminium tends to remain stable in the saprolite. However, Fe shows contrasting mobility during weathering of the different lithologies. For ultramafic rocks, there is a strong absolute Fe depletion in the clay saprolite, with minor depletion in the overlying mottled and plasmic clay. In contrast, within weathered porphyries, Fe is absolutely accumulated in the most regolith horizons, possibly representing reprecipitation of Fe dissolved from adjacent ultramafic rocks.

Results from this investigation agree well with a previous Au mass balance study based on isovolumetric calculations. However, differences higher in the regolith may be due to partial collapse causing errors in earlier calculations.
Regolith geology and geochemical exploration around the Stellar and Quasar gold deposits, Mt Magnet, Western Australia
Authors: Robertson I. D. M. , King J. D. , Anand R. R.
Published: July 2011

The Boogardie Synform, at Mt Magnet, in the NE Yilgarn Craton of Western Australia, is difficult to explore due to structural complexity in the basement, a variably truncated, residual regolith beneath a complex, transported overburden and high geochemical backgrounds from numerous mineralized settings. The distributions of Au and associated elements in the regolith around the Stellar and Quasar deposits, within the Boogardie Synform, have been studied to identify optimum sample media and an analytical suite for continuing exploration of this district. Regolith–landform relationships and geochemical dispersion in the district were established by mapping the regolith of an area of 25km
2
around the mines and investigating drill cuttings and pit exposures.

Mining and drilling at both sites revealed a partly eroded lateritic regolith incized by a fluvial palaeochannel, all concealed beneath 5–10 m of polymictic colluvium–alluvium. The sediments have all undergone post-depositional weathering. The Au mineralization is poor in As and Sb, but there are weak anomalies in Bi and Pb in the upper part of the weathered basement. There is no expression of the mineralization in the palaeochannel sediments or colluvium, nor between nearly adjacent layers within the colluvium and its overlying lag. Comparison of data from samples taken from the top of the basement with those from the unconformity, or interface, between basement and colluvium, indicates lower order but broader (200 m) and more consistent anomalies in the interface for Au, Bi and Pb. Useful anomalies can be improved using additive indices of Bi, Pb and Zn. The interface sample is, therefore, the preferred sample medium in this area of buried, truncated regolith, except where there are palaeochannels. Where there has been less regolith truncation and a buried, ferruginous duricrust is present, as at Stellar, duricrust is the optimum sample medium.

Elevated concentrations of Cr, Ni, Cu, V and, possibly, Zn in the basement regolith indicate mafic–ultramafic rocks. The saprolite and mottled zone on the basement rocks have a significantly greater Cr/Fe ratio than the transported materials. Regolith differentiation can be improved by robust canonical variate analysis; the most useful elements appear to be Al, Fe, Ni, Cr, Ga, Y, Zn, Th and Cu.
Komatiite volcanology, volcanological setting and primary geochemical properties of komatiite-associated nickel deposits
Authors: Hill R. E. T.
Published: July 2011

Komatiite-associated nickel sulphide deposits formed in long-lived lava conduits fed vast komatiite flow fields during the evolution of Archaean Greenstone Belt stratigraphy. Such komatiite flow fields exhibit complex internal volcanic stratigraphy and facies variations. This complex volcanic architecture renders the meaningful interpretation of geophysical and geochemical exploration data almost impossible, without a knowledge of the eruptive processes controlling the emplacement of the flow fields and their associated nickel deposits.

Accordingly, this paper presents an effective model for komatiite volcanism which is derived from a synthesis of extensive geological mapping, geochemistry, and petrology of Archaean komatiites in Western Australia, and studies of Recent and active basaltic eruptions. It discusses the implications of this inflationary model for the interpretation of the geological and geochemical properties of various volcanic facies, and the genesis and geochemical properties of the ore deposits and their immediate environments. It is hoped that this treatize will act as a ‘precautionary tale’ for those formulating nickel exploration programs and interpreting regolith geochemical data.
Weathering, element distribution and geochemical dispersion at Mt Keith, Western Australia: implication for nickel sulphide exploration
Authors: Brand N. W. , Butt C. R. M.
Published: July 2011

The komatiite–dunite-hosted Ni sulphide deposit at MKD5 (Mt Keith) has a complex regolith consisting of a residual profile (>75 m depth), partly collapsed towards the top, overlain by 40 m of exotic sediments. The weathered komatiites are composed predominantly of degraded serpentine, neo-formed hydrated Mg-silicates, carbonates, silica and Fe oxides. Magnesium concentrations decrease upwards through the lower regolith, whereas those of Fe and Si increase, reflecting degradation of Mg-bearing minerals. A sharp decline of Mg within the profile marks the
Mg discontinuity
, separating Mg-saprolite from the overlying Fe saprolite. The Fe saprolite, dominated by Fe oxides and silica, has pseudo-sedimentary structures indicating partial collapse of the profile. At the unconformity with the sediments, eluviation, mixing and churning have produced zones with chemical and mineralogical characteristics of the underlying, overlying and adjacent lithologies.

Nickel, Co, Mn, Cr and PGE are dominantly hosted by secondary Fe oxides in the regolith, but above the Mg-discontinuity, Ni and Co are locally enriched by co-precipitation with Mn oxides. The oxidation potential, controlled by ferrolysis, ranges from −0.4 to +0.2 volts, and the pH, buffered by bicarbonate ion, irrespective of the presence of sulphides, decreases from 9.5 to 6.0 up through the profile. Copper is not significantly mobile under such conditions and precipitates as inert native metal, commonly spatially associated with Fe oxides. Separation of Ni and Cu occurs in the upper saprolite and pedolith, because metallic Cu (±Pd) is retained and residually concentrated in collapsed Fe saprolite, whereas Ni, adsorbed to goethite, is redissolved and reprecipitated below the Mg-discontinuity.

High Ni concentrations in the regolith cannot alone be used to distinguish between Ni sulphide mineralized (NiS) and barren komatiitic protoliths. The strong correlation between chalcophile elements evident in mineralized protolith is lost with the oxidation of sulphides, and Ni derived from sulphides is indistinguishable from that derived from silicates. Ultramafic-derived regolith materials having Ni/Cu ratios of 7–19 and >19 may indicate the presence of massive and disseminated sulphides, respectively. The ratio at MKD5 is 60. These relationships may be distorted by preferential leaching, or by the influx of either element from wall-rocks. High concentrations of PGE, especially Pt, Pd and Ru, may also indicate mineralized protolith. However, the very low secondary mobility of PGE and Cu greatly restricts target size. Larger targets are given by Ni/Cr and Cu/Zn ratios which, either singly or multiplied together, can be used to identify mineralized komatiitic sequences and provide vectors towards ore. Their value is diminished if the ore and host sequence are decoupled during emplacement.
Carboniferous stratigraphy and context of the Seal Sands No. 1 Borehole, Teesmouth, NE England: the deepest onshore borehole in Great Britain
Authors: Johnson G. A. L. , Somerville Ian D. , Tucker Maurice E. , Cózar Pedro
Published: July 2011

Carboniferous rocks totalling 3442 m in thickness were drilled in the Seal Sands No. 1 Borehole at Teesmouth, Cleveland, in 1974–75. Cores taken in the middle and towards the bottom of the Carboniferous section show that the strata are broadly horizontal so the thicknesses drilled are close to true stratigraphical thicknesses. The borehole passed through 727 m of Triassic and Permian strata, which lie unconformably on the Carboniferous rocks. The latter comprise a Mississippian succession of Viséan–Serpukhovian (Holkerian–?Arnsbergian) age that is dominated by near-shore, shallow-water deposits with numerous but mainly thin coal seams. The Serpukhovian (Pendleian–?Arnsbergian) succession of shales and siltstones with thin sandstones, several thin limestones and rare coals is assigned to the Stainmore Formation (135 m). Below this, a thick calcareous interval of limestone and interbedded mudstone is believed to be the Great Limestone (110 m), which forms the top member of the underlying upper Viséan (Brigantian)–lower Serpukhovian (Pendleian) Alston Formation. The remaining strata of the Alston Formation (782 m) are equivalent to the 10 principal cyclothems (Four Fathom–Peghorn limestones) of the Alston Block, together with the underlying Birkdale Limestone at the base of the Alston Formation from which the lowest Brigantian microfossils have been recorded. The underlying Great Scar Limestone Group of late Asbian age (148 m) includes pale limestones of the Melmerby Scar Limestone Formation, similar to the limestones of the same formation on the Alston Block, interbedded with sandstones and mudstones. Below the Great Scar Limestone Group, the new informally defined Cleveland Group comprises three new informally defined formations. At the top of the group, the Greatham Formation (388 m) comprises limestones interbedded with mudstone and sandstone in cyclic sequences of late Asbian age. Below this, the informally defined Teesmouth Formation (539 m), also of late Asbian age, is a more terrigenous succession with numerous coal seams. The oldest unit in the borehole, the informally defined Seal Sands Formation (1338 m), comprises finely interbedded, black fissile mudstone, siltstone, fine-grained sandstone, thin black peloidal limestone beds, black chert and many coal seams. This distinctly black succession is mostly Asbian in age, but Holkerian microfossils occur in the lower part, from 3621 m down to the bottom of the hole at 4169 m. Correlations are made with the Alston Block succession and that of the Stainmore Basin. The unusually thick Mississippian succession, especially in the Asbian (>1800 m thick), is in accordance with the borehole's location within the eastern part of the Stainmore Basin, where a thick Carboniferous sequence is inferred from geophysical data. It is also comparable with a thick Asbian succession in the Northumberland Basin.