bluuebunny/crossref_metadata_2025 huggingface dataset:
A kinetic theory derivation of the second and third virial coefficients of rigid rods, disks, and spheres
Authors: Bishop Marvin
Published: March 2005

The second and third virial coefficients of rigid rods, disks, and spheres are obtained using the kinetic theory of gases.
Radiative forces on neutral atoms—A classical treatment
Authors: Zilio S. C. , Bagnato V. S.
Published: March 2005

A classical treatment is presented for the radiative forces acting on a neutral atom subjected to a monochromatic electromagnetic field. These forces are classified as spontaneous and induced. The spontaneous force gives rise to a recoil of the atom and a blue shift of the resonance frequency due to the Doppler effect. The induced force is directed along the intensity gradient and is very important for trapping purposes. The results are compared to those obtained by means of a semiclassical model and differences of interpretation are pointed out.
Nonlinear and chaotic string vibrations
Authors: Tufillaro Nicholas B.
Published: March 2005

The nonlinear vibrations of an elastic string are studied. A string is capable of showing nonlinear phenomena including periodic, quasiperiodic, and chaotic motions. Hysteresis is found using the method of slowly varying amplitudes, and chaotic vibrations are predicted for an experimentally accessible regime.
A remark on the gravitational field produced by an infinite straight string
Authors: Francisco G. , Matsas G. E. A.
Published: March 2005

The results predicted by Newtonian gravity and general relativity are compared regarding the field produced by an infinite gauge string with constant density λ. A simple gedankenexperiment is suggested to stress the remarkable differences between these two theories. The existence of the usual Newtonian limit is discussed in this case.
Deriving a formula for nuclear radii using the measured atomic masses of elements
Authors: Gauthier N.
Published: March 2005

Most nuclei have a nearly spherical shape and can be characterized by an effective radius R=R0 A1/3, where A is the nucleon number and R0 is a constant to be determined from experimental data. Traditionally, the data came from experiments on muonic or pionic x-ray emission, high-energy electron scattering, optical or x-ray isotope shifts, β emission by mirror nuclei, α decay, or neutron scattering. Because this type of information is not readily available in textbooks or the pedagogical literature, it is difficult to ask students to establish the radius formula on their own. However, as shown here, one may easily circumvent the difficulty by using the readily available and highly accurate masses of the mirror nuclei. Results are presented for all existing pairs of mirror nuclei.
Thermodynamics as the continuum limit of statistical mechanics
Authors: Compagner A.
Published: March 2005

The thermodynamic limit in statistical mechanics is often equivalent to a properly defined continuum limit, in which Boltzmann’s constant k vanishes together with the microscopic scales of length and time. In this continuum limit, which is the missing link between statistical mechanics and the historical development of thermodynamics, all microscopic fluctuations are suppressed, just as the quantum mechanical uncertainties are in the classical limit; these two limits are similar, but can be taken independently. The continuum limit is to be preferred above the thermodynamic limit when macroscopic dependences on space or time are present and may help to solve conceptual problems. As an example, capillary phenomena are discussed with particular attention to Kelvin’s equation. The enforced behavior of coupling constants in the continuum limit stresses the phenomenological and approximate status of thermodynamics. The relation with other reduction schemes of macroscopic physics is indicated, and possible consequences for ergodic theory are sketched.
A novel method for solving a class of differential equations
Authors: Weinstock Robert
Published: March 2005

Application of a previously introduced device is extended so as to effect straightforward solutions of first-order differential equations of a particular class encountered in the calculus of variations.
Introducing Schrödinger’s cat in the laboratory
Authors: Axon T. J.
Published: March 2005

A laboratory session that is designed to introduce students to the conceptual foundations of quantum mechanics is described. In this laboratory session, several experiments are used in order to illustrate the important ideas of superposition, interference, and the ‘‘collapse’’ of the wavefunction. These experiments form the basis for a discussion of four of the most popular interpretations of quantum mechanics that have been proposed over the years: the instrumentalist interpretation, hidden variable theories, the objective view of the wavefunction, and the many-worlds interpretation. As a finale, students are introduced to the paradox that epitomizes the interpretational problems of quantum mechanics: the paradox of Schrödinger’s cat.
Analysis of Human Immunodeficiency Virus Cytopathicity by Using a New Method for Quantitating Viral Dynamics in Cell Culture
Authors: Speirs Christina , van Nimwegen Erik , Bolton Diane , Zavolan Mihaela , Duvall Melody , Angleman Sara , Siegel Richard , Perelson Alan S. , Lenardo Michael J.
Published: March 2005

Human immunodeficiency virus (HIV) causes complex metabolic changes in infected CD4
+
T cells that lead to cell cycle arrest and cell death by necrosis. To study the viral functions responsible for deleterious effects on the host cell, we quantitated the course of HIV type 1 infection in tissue cultures by using flow cytometry for a virally encoded marker protein, heat-stable antigen (HSA). We found that HSA appeared on the surface of the target cells in two phases: passive acquisition due to association and fusion of virions with target cells, followed by active protein expression from transcription of the integrated provirus. The latter event was necessary for decreased target cell viability. We developed a general mathematical model of viral dynamics in vitro in terms of three effective time-dependent rates: those of cell proliferation, infection, and death. Using this model we show that the predominant contribution to the depletion of viable target cells results from direct cell death rather than cell cycle blockade. This allows us to derive accurate bounds on the time-dependent death rates of infected cells. We infer that the death rate of HIV-infected cells is 80 times greater than that of uninfected cells and that the elimination of the vpr protein reduces the death rate by half. Our approach provides a general method for estimating time-dependent death rates that can be applied to study the dynamics of other viruses.
Human Immunodeficiency Virus Type 1 Nef Potently Induces Apoptosis in Primary Human Brain Microvascular Endothelial Cells via the Activation of Caspases
Authors: Acheampong Edward A. , Parveen Zahida , Muthoga Lois W. , Kalayeh Mehrnush , Mukhtar Muhammad , Pomerantz Roger J.
Published: March 2005

The lentiviral protein Nef plays a major role in the pathogenesis of human immunodeficiency virus type I (HIV-1) infection. Although the exact mechanisms of its actions are not fully understood, Nef has been shown to be essential for the maintenance of high-titer viral replication and disease pathogenesis in in vivo models of simian immunodeficiency virus infection of monkeys. Nef has also been suggested to play a pivotal role in the depletion of T cells by promoting apoptosis in bystander cells. In this context, we investigated the ability of extracellular and endogenously expressed HIV-1 Nef to induce apoptosis in primary human brain microvascular endothelial cells (MVECs). Human brain MVECs were exposed to baculovirus-expressed HIV-1 Nef protein, an HIV-1-based vector expressing Nef, spleen necrosis virus (SNV)-Nef virus (i.e., SNV vector expressing HIV-1 Nef as a transgene), and the HIV-1 strain ADA and its Nef deletion mutant, ADAΔNef. We observed that ADA Nef, the HIV-1 vector expressing Nef, and SNV-Nef were able to induce apoptosis in a dose-dependent manner. The mutant virus with a deletion in Nef was able to induce apoptosis in MVECs to modest levels, but the effects were not as pronounced as with the wild-type HIV-1 strain, ADA, the HIV-1-based vector expressing Nef, or SNV-Nef viruses. We also demonstrated that relatively high concentrations of exogenous HIV-1 Nef protein were able to induce apoptosis in MVECs. Gene microarray analyses showed increases in the expression of several specific proapoptotic genes. Western blot analyses revealed that the various caspases involved with Nef-induced apoptosis are processed into cleavage products, which occur only during programmed cell death. The results of this study demonstrate that Nef likely contributes to the neuroinvasion and neuropathogenesis of HIV-1, through its effects on select cellular processes, including various apoptotic cascades.
Roles of the Ras-MEK-Mitogen-Activated Protein Kinase and Phosphatidylinositol 3-Kinase-Akt-mTOR Pathways in Jaagsiekte Sheep Retrovirus-Induced Transformation of Rodent Fibroblast and Epithelial Cell Lines
Authors: Maeda Naoyoshi , Fu Wuxia , Ortin Aurora , de las Heras Marcelo , Fan Hung
Published: March 2005

Jaagsiekte sheep retrovirus (JSRV) is the causative agent of ovine pulmonary adenocarcinoma (OPA), a transmissible lung cancer of sheep. The virus can induce tumors rapidly, and we previously found that the JSRV envelope protein (Env) functions as an oncogene, because it can transform mammalian and avian fibroblast cell lines. (N. Maeda, Proc. Natl. Acad. Sci. USA 98:4449-4454, 2001). The molecular mechanisms of JSRV Env transformation are of considerable interest. Several reports suggested that the phosphatidylinositol 3-kinase/Akt pathway is important for transformation of mammalian fibroblasts but not for chicken fibroblasts. In this study, we found that Akt/mTOR is involved in JSRV transformation of mouse NIH 3T3 fibroblasts, because treatment with the mTOR inhibitor rapamycin reduced transformation. We also found that H/N-Ras inhibitor FTI-277 and MEK1/2 inhibitors PD98059 and U0126 strongly inhibited JSRV transformation of NIH 3T3 fibroblasts, suggesting that the H/N-Ras-MEK-mitogen-activated protein kinase (MAPK) p44/42 pathway is necessary for the transformation. In RK3E epithelial cells, the MEK1/2 inhibitors also eliminated transformation, but FTI-277 only partially inhibited transformation. It was noteworthy that p38 MAPK inhibitors enhanced JSRV transformation in both fibroblasts and epithelial cells. Treatment of transformed cells with p38 inhibitors both increased levels of phospho-MEK1/2 and phospho-p44/42 and induced rapid enhancement of the transformed phenotype. Immunohistochemical staining of tumor tissues from naturally and experimentally induced OPA and naturally occurring enzootic nasal adenocarcinoma revealed strong activation of MAPK p44/42 in all cases examined. However, p38 activation was not generally observed. These results indicate that signaling through two pathways (in particular, H/N-Ras-MEK-MAPK and, to a lesser extent, Akt-mTOR) is important for JSRV-induced transformation and that p38 MAPK has a negative regulatory effect on transformation, perhaps via MEK1/2 and p44/42.
Complex Memory T-Cell Phenotypes Revealed by Coexpression of CD62L and CCR7
Authors: Unsoeld Heike , Pircher Hanspeter
Published: March 2005

Antigen-experienced T cells have been divided into CD62L
+
CCR7
+
central memory (T
CM
) and CD62L
−
CCR7
−
effector memory (T
EM
) cells. Here, we examined coexpression of CD62L and CCR7 in lymphocytic choriomeningitis virus-specific memory CD8 T cells from both lymphoid and nonlymphoid tissues. Three main points emerged: firstly, memory cells frequently expressed a mixed CD62L
−
CCR7
+
phenotype that differed from the phenotypes of classical T
EM
and T
CM
cells; secondly, T
CM
cells were not restricted to lymphoid organs but were also present in significant numbers in nonlymphoid tissues; and thirdly, a major shift from a T
CM
to T
EM
phenotype was found in memory cells that had been stimulated repetitively with antigen.
Genetics and health inequalities: hypotheses and controversies
Authors: Mackenbach Johan P
Published: March 2005

This article reviews the current understanding of the explanation of socioeconomic inequalities in health in industrialised countries and then tries to determine where genetic factors could fit into explanatory schemes. It focuses on the explanation of socioeconomic inequalities in frequency of the main health problems of middle and old age.
PIONIC HYDROGEN
Authors:   FOR THE PIONIC HYDROGEN COLLABORATION, GOTTA DETLEV
Published: March 2005

The measurement of the pion–nucleon scattering lengths constitutes a high–precision test of the methods of Chiral Pertubation Theory (χPT), which is the low–energy approach of QCD. The πN s–wave scattering lengths and the pion–nucleon coupling constant are related to the strong–interaction shift ∊1s and width Γ1s of the s–states in the pionic hydrogen atom. ∊1s and Γ1s are determined from the measured energies and line widths of X–ray transitions to the 1s ground state when compared to the calculated electromagnetic values. A new experiment, set up at the Paul–Scherrer–Institut (PSI), has completed a first series of measurements.
BELLE RESULTS ON TIME DEPENDENT CP VIOLATION IN B DECAYS
Authors:   FOR THE BELLE COLLABORATION, ISHINO HIROKAZU
Published: March 2005

We report on measurements of time-dependent CP-violation parameters in neutral B meson systems based on a 140fb -1 data sample collected at the ϒ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. One B meson is fully reconstructed in one of the CP eigenstate decay channels, and its flavor is identified from the decay products of the accompanying B meson. The CP-violation parameters are extracted from the asymmetries in the distributions of the proper-time intervals between the two B decays. The parameter sin 2ϕ1 is measured with the decay modes including the b→c tree and b→s penguin transitions, and sin 2ϕ2 is obtained from the decay mode B→π+π-. A brief discussion of the ϕ3 measurements with B→D(*)∓π± decays is also given.
FIRST RESULTS FROM CLEO-c
Authors:   FOR THE CLEO COLLABORATION., BRIERE ROY A.
Published: March 2005

We present the first results from a recent pilot run of the CLEO-c experiment. This new program investigates the physics of charm mesons and charmonium resonances. We begin with results on two-body decays of the ψ(2S); first observations of some highly-suppressed "PV" modes are presented. Next, data taken at the ψ(3770) are used for a variety of studies of D meson decays in a very clean environment. We report the [Formula: see text] cross-section at the ψ(3770), extract fD from the first significant sample of D+→μ+νμ decays, and investigate both inclusive and exclusive semileptonic D decays.
η DECAYS WITH WASA DETECTOR
Authors:   FOR THE CELSIUS/WASA COLLABORATION., KUPŚĆ ANDRZEJ
Published: March 2005

Experimental programme of eta decays carried out at WASA detector is presented. Not-so-rare eta decays are well suited as a low energy QCD laboratory. For example decay η→3π is a valuable source of information on light quark masses. In very rare eta decays such as η→e+e- and η→π°e+e- fundamental aspects of the Standard Model can be tested. Production reactions – sources of eta mesons for the decay studies at storage rings such as CELSIUS and COSY are discussed. Prospects of eta decay physics for WASA@COSY are presented.
MEASUREMENTS OF MASSES AND WIDTHS OF EXCITED CHARM MESONS $D_2^*$, EVIDENCE FOR BROAD STATES AND OBSERVATION OF $D_S^+(2317)$ FROM FOCUS EXPERIMENT
Authors:   ON BEHALF OF THE FOCUS COLLABORATION: Co-authors are: J. M. Link, P. M. Yager (UC Davis); J. C. Anjos, I. Bediaga, C. Göbel, A. A. Machado, J. Magnin, A. Massafferri, J. M. de Miranda, I. M. Pepe, E. Polycarpo, A. C. dos Reis (CBPF, Rio de Janeiro); S. Carrillo, E. Casimiro, E. Cuautle A. Sánchez-Hernández, C. Uribe, F. Vázquez (CINVESTAV, Mexico City); L. Agostino, L. Cinquini, J. P. Cumalat, B. O'Reilly, I. Segoni, K. Stenson (CU Boulder); J. N. Butler, H. W. K. Cheung, I. Gaines, P. H. Garbincius, L. A., BENUSSI LUIGI
Published: March 2005

I report three new results from photoproduction experiment FOCUS on L=1 excited meson spectroscopy: precise measurements of the masses and widths of the [Formula: see text] and [Formula: see text] mesons, evidence for broad states decaying to D+π-, D0π+ (the first such evidence in D0π+), and confirmation of the recently observed [Formula: see text] charmed-strange state.
FCNC DECAYS OF B MESONS
Authors:   FOR THE BELLE COLLABORATION., KRIŽAN PETER
Published: March 2005

The paper reviews recent results from the Belle experiment on the flavor changing neutral current processes b→sγ, b→dγ and b→sℓ+ℓ-. We report on a new measurement of the b→sγ inclusive rate and of the moments of the photon energy distribution. We also present the measurements of rate, isospin asymmetry and CP violation in the B→K*γ decays, as well as the CP asymmetry measurement in the inclusive B→Xsγ transitions. We report on the evidence for exclusive b→dγ transitions, and finally present the first observation of the B→K*ℓ+ℓ- decay and updated measurements of the B→Kℓ+ℓ- and B→Xsℓ+ℓ- branching fractions.
OPEN b PRODUCTION IN TWO-PHOTON COLLISIONS IN DELPHI
Authors:   ON BEHALF OF THE DELPHI COLLABORATION., KAPUSTA FRÉDÉRIC
Published: March 2005

Heavy b and c quark production in γγ collisions has been measured through semileptonic decays with the DELPHI detector at LEPII. The measured cross-sections are compared to NLO perturbative QCD calculations. The cross-section for b production is found to exceed QCD predictions. The K-lepton double tagging, used for the first time in γγ physics confirms this excess.
STATUS OF ASYMMETRY MEASUREMENT AND RARE DECAYS AT NA48/2 EXPERIMENT
Authors:   FOR THE NA48/2 COLLABORATION., MOLOKANOVA NATALIA
Published: March 2005

A high statistics study of charged kaon decays, using a novel design for simultaneous K+/K- beams and an upgraded NA48 setup, is in progress. The main goal is to measure the CP-violating asymmetry in the matrix element linear slope of the K±→π+π-π± decays with an accuracy of 2.2×10-4. In addition, the analogous CP-violating asymmetry is measured in K±→π0π0π± decays. More than 106 Ke4 decays allow to measure the scattering length parameter [Formula: see text] with an accuracy better than 0.01, and some other rare decays of charged kaons are studied as well.
RADIATIVE VECTOR MESON DECAYS: ω→π0ηγ AND ρ→π0ηγ
Authors: KUCUKARSLAN AYSE
Published: March 2005

We study the ω and ρ decays into π0ηγ using phenomenological approach by adding to the amplitude calculated with in the framework of VMD, chiral loop, a0-meson intermediate state and ρ-omega-mixing. a0-meson intermediate state amplitude makes a small contribution for two decays when considering to proceed by a two step mechanism.
Chemostat-controlled selective leaches of model soil phases – the hydrous manganese and iron oxides. Part 1
Authors: Nolan Annette L. , Baltpurvins Karlis , Hamilton Ian C. , Lawrance Geoffrey A.
Published: March 2005

Selective leaching of synthetic Mn and Fe oxide phases were examined using a Chemostat to control the system temperature, pH and/or Eh. Reaction conditions for the selective dissolution of model phases of Mn oxide (birnessite, ‘MnO
2
’), amorphous Fe oxyhydroxide (ferrihydrite, Fe(OH)
3
.
x
H
2
O) and crystalline Fe oxide (hematite/goethite, Fe
2
O
3
/FeOOH) were optimized, concomitant with the behaviour of their dopant metals Cu, Pb and Zn. The pure oxide phases, as well as model compounds doped via coprecipitation with Cu, Pb and Zn, each to a concentration of 1000 ppm with respect to the mass of the oxide phase, were employed. Quantitative dissolutions of the target model phases were achieved within relatively short reaction times (within 15 min) for the purpose of high throughput field procedures. A limited study of three soil samples collected from a Pb–Zn–Ag mining province in northern Queensland, Australia was conducted employing the leach conditions found to provide optimal selectivity.
Redox, pH and SP variation over mineralization in thick glacial overburden. Part II: field investigation at Cross Lake VMS property
*
Authors: Hamilton S.M. , Cameron E.M. , McClenaghan M.B. , Hall G.E.M.
Published: March 2005

An investigation of surface and subsurface redox and electrical field conditions was carried out over a volcanogenic massive sulphide (VMS) deposit in thick glacial clay and sand terrain of the Abitibi clay belt of northeastern Ontario. Thirty-seven boreholes were drilled to 9 m depth on two lines crossing the strike of mineralization and were completed in either sand or clay. An additional three were drilled 30 to 50 m and completed in bedrock. Monitoring wells were installed in all holes and groundwater was later sampled. A variety of oxidation–reduction potential (ORP) and spontaneous potential (SP) techniques were used, the methodologies for which were introduced earlier and are further developed here. The best definition of redox conditions was obtained by ORP measurement of clay and sand slurries from split-spoon samples collected and analysed during the drilling programme. Related techniques included groundwater ORP and down-hole platinum-SP (PtSP) testing, the latter measuring total potential field, which is the sum of the electrical and electrochemical components of voltage. Although the performance of the methods differed, the results consistently show chemically reduced areas (reduced ‘columns’) in the phreatic zone above mineralization with overlying acidic ‘caps’ in the vadose zone. Other features noted over mineralization include carbonate remobilization, partial extraction metal anomalies in shallow soils, CO
2
enrichment in groundwater, and elevated groundwater temperature. These varied features are related and provide evidence for upward transport of reduced species from mineralization. They agree well with phenomena predicted in a previously published redox-gradient transport model.

SP was measured, both down-hole and on surface, and shows a weakly negative electrical field response over mineralization. This response is small in comparison to the redox response and is interpreted to occur because, in addition to being oxidizable, the sulphide is also conductive and SP currents within it produce a small electrical field. It is postulated that oxidizable but non-conductive features such as sphalerite, would also produce a reduced column but without an electrical field, whereas, conductive, non-oxidizable features such as graphite would produce an electrical field but with little or no redox response.
A remote-sensing method of mapping soils and surficial lags from a deeply weathered arid region, near Cobar, NSW, Australia
Authors: Dehaan R.L. , Taylor G.R.
Published: March 2005

The work reported here describes the use of hyperspectral imagery for discriminating and mapping the mineralogy of surface materials at a semi-arid site in New South Wales, Australia. Hyperspectral imagery for the Mrangelli test site near Cobar was acquired by the HyMap instrument, a 126-channel, high spectral and spatial resolution airborne scanner. Ground investigations demonstrate that HyMap is able to acquire spectra of 5 m pixels that have a similar spectral resolution to spectra acquired with a field spectrometer. Unmixing of endmembers from calibrated HyMap imagery allowed outcrops of maghemite-rich pisoid lags, lithic lags, ferrolithic lags, metasediments and soils to be discriminated and mapped. The pisoid lag is shown by field and image spectra to be a mixture of hematite/maghemite Fe oxides and kaolinite. Lithic lags show features that resemble mixtures of hematite and illite. Class maps derived from the visible and near-infrared (VISNIR) part of the spectrum delineate terrain elements distinguished by their Fe mineralogy and content. Class maps derived from the shortwave infrared part (SWIR) of the spectrum delineate terrain elements distinguished by their clay mineralogy, content and crystallinity. Unique combinations of VISNIR- and SWIR-derived terrain elements define geomorphic terrains common within the region. It is proposed that maps of lag distribution and the accompanying terrains derived from HyMap imagery could be used to differentiate
in-situ
from transported materials and therefore aid in the planning of sample locations for soil and lag geochemistry exploration programmes.
Regional distribution and sources of Au, Pd and Pt in moss and O-,B- and C-horizon podzol samples in the European Arctic
Authors: Niskavaara H. , Kontas E. , Reimann C.
Published: March 2005

A cost-effective analytical method for analysing various terrestrial sample materials for noble metals at detection limits in the sub-ppb range has been developed. The method has been used to analyse
c.
600 samples of moss, O-, B- and C-horizon samples collected from a large area (188,000 km
2
) in the European Arctic at a sample density of 1 site/300 km
2
. For the first time reliable analytical data for Au, Pd and Pt for a large, statistically representative number of samples from four different sample materials can be reported. The regional distribution of Au, Pd and Pt in moss and O-horizon samples provides clear evidence that the Russian nickel industry on the Kola Peninsula is emitting Au and platinum group elements (PGEs). However, maps and profiles for moss and the O-horizon also demonstrate that the emissions of one of the very few and largest Pd emission sources on earth cannot be traced further than 200 km on the ground before reaching background values. The predominant natural geochemical characteristics of the study area are visible in the maps of the B- and C-horizon samples even when using such low-density sampling. Furthermore, the data allow estimation of realistic ‘background values’ for these three elements in the four sample materials. By collecting four interrelated sample materials from a large area it is possible to detect unusual processes leading to the enrichment of certain elements in specific compartments of the ecosystem. Most dramatic is a greater than four-fold higher Pt concentration in the B-horizon of arctic podzols compared to all other media. Platinum concentrations are also slightly higher in the O-horizon than in the C-horizon. Palladium shows a tendency to organic binding. Moss is actively enriching Pd and shows even higher Pd concentrations than in the O-horizon. The highest Au values can be found in the deepest soil layers (C-horizon). Natural, geogenic sources influence Au concentrations measured in moss and the O-horizon as much as industrial emissions.
The effects of seasonal changes, sample site drainage and tree morphology on trace element contents of black spruce (

Picea mariana

(Mill.) BSP) crown twigs and outer bark
Authors: Sailerova E. , Fedikow M.A.F.
Published: March 2005

A positive correlation between soil metal content and plant metal accumulation has been used by biogeochemists to assist mineral exploration in areas of minimal outcrop. Much-needed study of the impact of vegetation sample collection over an extended time-frame, impact of site drainage, as well as the choice of vegetation sample type are presented. Evaluation of seasonal variability, together with measurements of tree water flow-rate (affected by weather conditions) on tree crown metal uptake was also undertaken to ascertain whether this variability could mask the geochemical signatures or whether normalization to weather conditions is needed. Thirty-three elements, including Au, Ag, Ni, Co, Zn and Cu, were studied. Other factors such as tree crown, outer bark and tree appearance were also studied. Black spruce was selected due to its ubiquitous presence in the boreal forest of central Manitoba. The best agreement between the crown twig metal accumulation and tree water uptake was identified for the rare earth elements (REEs) and the essential elements (Ca, K, Mg, Fe, P, Zn), which also exhibited the highest seasonal variation. The content of pH-sensitive elements (Ag, Co, Ni, Rb, Mn, Cu) in black spruce crowns did not display any direct relationship to the tree water uptake. Elements most affected by site drainage conditions include Ag, Co, Ni, Rb, Mn and Cu. These metals were found in substantially larger quantities in crowns of trees growing on well drained sites. Gold concentrations in outer bark samples growing on well drained sites were 12 times lower than the same samples collected from poorly drained sites. Au, Pb, W, Th, Na, Al were found in substantially larger concentrations in thin (up to 4 mm in diameter) compared to thicker twigs. Ag and Ca accumulated preferentially in thick twigs. K, Mg, P, Mn, Zn, Cu, Au, Ag, Rb and W were present in substantially higher concentrations in the crown twigs compared to outer bark. Pb, B, Hf, Th, V and REEs were present in the outer bark at eight to ten times higher concentrations than in crown twigs, and Hf, Na, Sb, Sc and V five times higher. W was not detectable in the outer bark but its content in the twigs was well above the detection limit. Crown morphology, the outer bark appearance and the number of tree transpiring branches had no measurable effect on metal contents in the assessed tree organs.
Metal dispersion and mobility in soils from the Lik Zn–Pb–Ag massive sulphide deposit, NW Alaska: environmental and exploration implications
Authors: Kelley Karen D. , Kelley David L.
Published: March 2005

The Lik deposit in northern Alaska is a largely unexposed shale-hosted Zn–Pb–Ag massive sulphide deposit that is underlain by continuous permafrost. Residual soils overlying the mineralized zone have element enrichments that are two to six times greater than baseline values. The most prominent elements are Ag, Mo, P, Se, Sr, V by total 4-acid digestion and Tl by a weak partial digestion (Enzyme Leach or EL) because they show multi-point anomalies that extend across the entire mineralized zone, concentration ranges are 0.5–2.6 ppm Ag, 4–26 ppm Mo, 0.1–0.3% P, 3–22 ppm Se, 90–230 ppm Sr, 170–406 ppm V, and 1.6–30 ppb Tl. Lead, Sb, and Hg are also anomalous (up to 178 ppm, 30 ppm, and 1.9 ppm, respectively), but all are characterized by single point anomalies directly over the mineralized zone, with only slightly elevated concentrations over the lower mineralized section. Zinc (total) has a consistent baseline response of 200 ppm, but it is not elevated in soils overlying the mineralized zone. However, Zn by EL shows a distinct single-point anomaly over the ore zone that suggests it was highly mobile and partly adsorbed on oxides or other secondary phases during weathering.
In situ
analyses (by laser ablation ICP-MS) of pyrite and sphalerite from drill core suggest that sphalerite is the primary residence for Ag, Cd, and Hg in addition to Zn, and pyrite contains As, Fe, Sb, and Tl.

The level and degree of oxidation, and the proportion of reacting pyrite and carbonate minerals are two factors that affected the mobility and transport of metals. In oxidizing conditions, Zn is highly mobile relative to Hg and Ag, perhaps explaining the decoupling of Zn from the other sphalerite-hosted elements in the soils. Soils are acidic (to 3.9 pH) directly over the deposit due to the presence of acid-producing pyrite, but acid-neutralizing carbonate away from the mineralized zone yield soilsthat are near neutral. The soils therefore formed in a complex system involving oxidation and weathering (mechanical and chemical) of sulphide minerals, dissolution of carbonate minerals, and precipitation of iron and manganese oxide minerals.
Geochemical dispersion in groundwater from a weathered Cu–Zn deposit in glaciated terrain
Authors: Gilliss M.L. , Al T.A. , Blowes D.W. , Hall G.E.M. , MacLean B.
Published: March 2005

Weathering of mineral deposits under glacial cover may slowly release elements to the groundwater that disperse forming secondary geochemical halos. The Tillex Cu–Zn deposit subcrops beneath a sand aquifer and glacial clay/silt aquitard that extends to the surface. A conceptual model was developed based on hydrologic, geochemical and mineralogical data to describe dispersion in the aquifer and aquitard overlying the mineralization. In the recharge zone, dissolved oxygen oxidizes detrital sulphides in the aquifer and aquitard, which promotes the dissolution of carbonate minerals, increasing the concentrations of Ca and Mg. Iron released by sulphide oxidation precipitates as Fe
(III)
oxyhydroxides. Trace metals released during sulphide oxidation may be subsequently adsorbed onto, or co-precipitated with, clays and Fe oxyhydroxides. Sulphate-reducing conditions occur deep in the aquifer over the mineralization and there is no evidence of metal transport upward through the overlying sand and clay/silt overburden. The sulphate-reducing conditions are not favourable for the development of a plume of weathering products that could represent a target for mineral exploration. The one-dimensional reactive transport model PHREEQC was used to test the conceptual model by simulating the hydrogeochemical conditions in the aquitard. The observed data correspond well to the model results, suggesting that the conceptual model is reasonable.
Geochemical effects of endoskarn formation in the Mazraeh Cu–Fe skarn deposit in northwestern Iran
Authors: Karimzadeh Somarin A.
Published: March 2005

The Mazraeh Cu–Fe skarn deposit, located in the Ahar region of northwestern Iran, is currently being mined and contains reserves of about 400,000 tons grading 1.2 wt% Cu. The deposit contains both exoskarn formed within the calcareous wall rock and endoskarn formed within the associated granodiorite. Mineralogically, there are three types of skarn at Mazraeh: (1) pyroxene exoskarn; (2) garnet endoskarn and exoskarn; and (3) secondary epidote skarn. Locally, gradational alteration of the Mazraeh granodiorite to garnet endoskarn is present over a width of one metre. Mass-balance calculations show that garnetization of the Mazraeh granodiorite was the result of interaction with a hydrothermal solution enriched in Si, Fe
2+
, Fe
3+
, Mn, Ca, Mg, P, Ag, Cu, Zn, La, Pb, Cd, Mo, and Y. These elements are thought to have originated from the magma. The calcareous wall rocks (limestone and marble) were the main source of Ca and Mg within the endoskarn. This hydrothermal alteration resulted in an average 157% volume gain in the affected wall rocks. The dilatent structures and open spaces were filled by paragenetically younger minerals, especially magnetite, pyrite, chalcopyrite, bornite, covellite, chalcocite, epidote, calcite and quartz, during the late stage of alteration. During the endoskarnification process, primary biotite, hornblende and titanite in the Mazraeh granodiorite have been replaced by chlorite and rutile, and plagioclase and K-feldspar have been replaced by garnet. These reactions have leached (removed) K, Na, Ba, Rb and possibly Sr and added Si, Fe, Mn, Ca, Mg, P, Ag, Cu, Zn, La, Pb, Cd, Mo, W and Y.

Orthogonal jointing in the Mazraeh pluton played a significant role in the channelling and migration of the hydrothermal solutions in the pluton and development of the endoskarn. Although most of the copper and iron were precipitated in the exoskarn due to reaction between hydrothermal solutions and marble and limestone, locally significant skarn mineralization is also developed in the pluton. Although significant sulphide mineralization was not precipitated during garnet endoskarn formation, porosity and permeability created by this process served as the sites of sulphide mineral precipitation during late stages of skarn formation. Thus, the exploration for, and delineation of garnet endoskarn may result in the discovery of ore. Field guides for the exploration of garnet endoskarn include: (1) its high physical relief due to abundant garnet which is highly resistant to surface weathering processes; (2) predominance of red-brown andraditic garnet species over grossular-rich ones; and (3) local development of secondary malachite and azurite after primary Cu and Fe sulphides.
Anthropogenic vs. natural pollution: an environmental study of an industrial site under remediation (Naples, Italy)
Authors: Tarzia M. , De Vivo B. , Somma R. , Ayuso R. A. , McGill R. A. R. , Parrish R. R.
Published: March 2005

Heavy metal concentrations and Pb isotopic composition were determined in the soils, slags, scums and landfill materials from a shut down industrial (brownfield) site. This was the second largest integrated steelworks in Italy, and is now under remediation by a Government project. It is located in the outskirts of Napoli on the Bagnoli–Fuorigrotta plain (BFP), which is part of the Campi Flegrei (CF) volcanic caldera, where many spas and geothermal springs occur. The purpose of this work is to distinguish the natural (geogenic) component, originated by hydrothermal activity, from anthropogenic contamination owing to industrial activity. ‘
In-situ
sediments’ (soils), slags, scums and landfill materials from 20 drill-cores were selected from a network of 197 drills carried out on a 100 × 100 m grid, covering the entire brownfield site. In general, heavy metal enrichments in the upper 3 m of the cores strongly suggest mixing between natural (geogenic) and anthropogenic components. Pb isotopic data are suggestive of three potential end members, and confirm the existence of a strong natural component in addition to contamination from anthropogenic activities. The slags, scums and landfill materials have been proved, through mineralogy and leachate experiments, to be geochemically stable; this shows that metal pollutants are not bio-available and, hence, do not pose a risk to future developments on this site. The natural contribution of hydrothermal fluids to soil pollution, in addition to the non-bio-availability of metal pollutants from industrial materials, indicate that heavy metal remediation of soils in this area would be of little use. Continuous discharge from mineralized hydrothermal solutions would cancel out any remediation effort.
Fluid extraction from quartz in sheeted leucogranites as a monitor to styles of uranium mineralization: an example from the Rössing area, Namibia
Authors: Nex Paul , Herd Donald , Kinnaird Judith
Published: March 2005

The Rössing Mine area in Namibia contains uranium mineralization primarily within crustally derived post-collisional sheeted leucogranites. Adjacent to the mine in the SH area, a small 1-km long granite cupola of coalesced sheets is also characterized by elevated U levels. In the Rössing pit, in the SJ area, U is hosted by uraninite and secondary U minerals including beta-uranophane. Conversely, in the SH area, U is hosted principally by the pyrochlore-group mineral, betafite. Manometric determination of the proportions of H
2
O, CO
2
and non-condensables (mostly methane) has been carried out on inclusions within quartz from leucogranite samples from both the SH and SJ anomalies. This method has been able to distinguish between leucogranites of the SH and SJ areas which has not been possible with thermometric fluid inclusion studies or by major and trace element geochemical investigations. Fluid geochemistry of sheeted leucogranites from the SH area exhibit lower absolute H
2
O contents, lower H
2
O/CO
2
ratios and low total fluids compared to that from the SJ area. Fluid geochemistry and large ion lithophile (LIL) element data suggest that the occurrence of the SJ anomaly as a major uranium deposit is linked to the high H
2
O and total fluid contents. This study illustrates the usefulness of this technique to distinguish between economic mineralization and the sub-economic SH anomaly.
Mercury in surface waters of three mine-dominated river systems: Idrija River, Slovenia; Carson River, Nevada; and Madeira River, Brazilian Amazon
Authors: Bonzongo J. C. , Lyons W. B. , Hines M. E. , Warwick J. J. , Faganeli J. , Horvat M. , Lechler P. J. , Miller J. R.
Published: March 2005

This paper investigates the aqueous geochemistry of mercury (Hg) in three aquatic systems impacted by either past or present mining activities. The Idrija River in Slovenia flows near the Idrija mercury mine, the second largest mercury mine in the world, with continuous mining and smelting activities for five centuries. During this period, it has been estimated that over 30 000 tonnes of Hg have been released into the mine's surrounding environment, due to inefficient smelting technologies and Hg left behind in mine tailings within the river basin. In contrast to cinnabar mining in the Idrija River Basin, the Carson River in Nevada and the Madeira River in the Brazilian Amazon are impacted by metallic mercury (Hg
0
) used in the amalgamation process to extract gold (Au) and/or silver (Ag) from crude ores and fine alluvial materials. The Carson River Basin was the site of intensive Au- and Ag-mining for over 50 years in the late 1800s and early 1900s, resulting in an estimated 7000 tonnes of Hg lost to the river and its watershed. The Madeira River is a site of ongoing use of Hg
0
in Au-prospecting. This study reports on the level and speciation of Hg, as well as factors controlling levels of methyl-Hg using aqueous data. Surface water samples collected along longitudinal transects upstream of well-identified point sources of Hg, except for the Madeira River, to river deltas were analysed for Hg and geochemical parameters of interest. Samples from Idrija and Carson rivers show clear evidence of contamination, with Hg levels up to several hundreds of ng l
−1
downstream from main point sources. Unlike Idrija and the Carson rivers, water samples collected from the Madeira River exhibited much lower Hg levels (9.51 ng l
−1
on average,
n
 = 16). Measured physiochemical parameters are used to determine the fate of Hg in these three river systems.
Air–surface exchange of mercury in natural and anthropogenically impacted landscapes in Atlantic Canada
Authors: Beauchamp S. , Tordon R. , Phinney L. , Abraham K. , Pinette A. , MacIntosh A. , Rencz A. , Wong H. , Dalziel J.
Published: March 2005

Understanding the relative importance of various sources of mercury within ecosystems and their subsequent impact on biota requires a thorough understanding of the biogeochemical cycling of mercury. An important component of the biogeochemical mercury cycle involves the exchange of gas-phase mercury between the atmosphere and various landscape surfaces. This study examines air–surface exchange (flux) of gaseous elemental mercury in selected undisturbed and anthropogenically impacted aquatic and terrestrial landscape settings. The objective of this study was to quantify air–surface mercury exchange rates in these contrasting landscape settings, to put constraints on these rates and provide insight into physical processes controlling mercury flux. Mean daily mercury flux was typically low over natural forest soils varying from −0.4 (net deposition) to 2.2 ng m
−2
 h
−1
(net evasion). Minimum and maximum flux rates measured at these sites over the diurnal cycle ranged from a minimum of −1.3 to a maximum of 5.7 ng m
−2
 h
−1
. Low flux rates from forest soils was partially due to poor light penetration through the forest canopy. Average daily mercury flux over undisturbed glacial till soil at an open field site with full sun exposure was also low (0.9 ng m
−2
 h
−1
) compared to the same soil mixed over a depth of 2 m (8.0 ng m
−2
 h
−1
). Mean daily mercury flux rates measured over pristine freshwater lake surfaces were also low (0.7–6.5 ng m
−2
 h
−1
), although the overall range in flux varied more widely (−0.3 to 44 ng m
−2
 h
−1
). Total mercury concentrations in marine water at a moderately polluted coastal harbour site (mean
c.
0.8 ng l
−1
) and mean daily mercury flux rates over salt water (0.7 ng m
−2
 h
−1
) were similar to those measured over freshwater lakes. The highest daily average and diurnal range in mercury flux rates were measured at two abandoned gold mine tailings sites (130 and 237 ng m
−2
 h
−1
). The abandoned mine sites comprised tailings high in mercury content due to the past use of the mercury amalgamation process in gold extraction from the ore. Flux rates from tailings were two orders of magnitude higher than those observed over undisturbed native soils of similar parent material. Higher flux rates at the mine tailings sites were accompanied by ambient air concentrations 5–10 times background levels at 20 cm above the tailings. Mercury flux from vegetation has not been widely considered. A preliminary study of mercury flux from a white pine tree (
Pinus strobus
) indicated that actively growing trees might play a role in the atmospheric mercury cycle.
Contents of Cu, Ni and Zn in smelter-polluted soil–plant systems
Authors: Nieminen T. M. , Saarsalmi A.
Published: March 2005

Intact soil profiles including litter layer and ground vegetation were taken at five distances (0.5, 2, 4, 8 and 60 km) from a Cu–Ni smelter in Harjavalta, SW Finland. The soil cores were placed in 10 l pots and a 4 year-old, bare-rooted pine seedling (
Pinus sylvestris
L.) was planted in each. The containers were incubated for17 months in controlled greenhouse conditions. At the end of the experiment the seedlings were harvested and soil samples were taken from each pot and analysed for Cu, Ni and Zn. The absence of atmospheric metal deposition had no reducing effect on the exchangeable heavy-metal contents of the soil pots. Metal uptake by the plant seedlings during the experiment had a negligible effect on the exchangeable heavy-metal content of the soil cores from the most polluted sites. The increase in both the exchangeable and the total humus Cu, Ni and Zn concentrations in the 0.5 km soil cores during the experiment suggested that there were pools of accumulated metals in the thick litter layer on top of the humus.
Overview of the environmental geochemistry of mining districts in southwestern Sardinia, Italy
Authors: Cidu R. , Fanfani L.
Published: March 2005

In southwestern Sardinia the areas around Iglesias and Guspini–Arbus represent the heart of the former mining industry. Lead and zinc ores were extensively exploited from 1850 to 1995. Geochemical studies in these areas have identified the main sources of contamination to be from drainage of flooded mines, mining wastes and tailings abandoned in settling ponds, and exposed ores. The transport of the fine materials eroded from the tailings ponds contributes to spreading pollution over larger areas downstream. Concentrations of Pb, Cd and Zn in the streams draining the mining area (up to 1, 1.7, and 1000 mg l
−1
, respectively) are several orders of magnitude higher than those observed in rivers outside the mining areas in Sardinia (Pb: <0.004 mg l
−1
, Cd: <0.001 mg l
−1
, and Zn: <0.02 mg l
−1
), and greatly exceed the Italian drinking water standards (Pb: 0.01 mg l
−1
, Cd: 0.005 mg l
−1
, and Zn: 3 mg l
−1
).