Constraints on the Origin of Gold in the Meguma Zone, Ecum Secum area, Nova Scotia

Gold occurs mainly in laminated bedding-parallel quartz veins in the Goldenvllle Formation metawacke-slate sequence. The bedding-parallel veins formed by hydraulic fracturing before the beds were folded. Subsequently, during development of the folds, en echelon quartz veins formed on the fold limbs, and perhaps in the latest stage of folding, saddle reef veins formed along fold hinges. All these vein types are locally auriferous, but gold was first deposited during formation of the bedding-parallel veins. Absence of any through-going system of "feeder" veins as well as the formation of hydraulic fractures indicate that the rocks were not permeable during vein formation, and the quartz and gold were derived locally from the host strata. RÉSUMÉ L'or présent dans la suite métawacke-schiste de la Formation Goldenvllle est localisé principalement dans des veines de quartz laminles et parallèls à la stratification. Ces veines parallèls ià stratification furent formées par fracture hydraulique avant le plissement des lits. Par la suite, pendant l'amplification des lits, des veines de quartz en échelon furent formées sur les flancs de plis et peut-être, pendant la phase finale de plisseaent, des veines en "gite de selle" se formèrent à la charnière de plis. Tous ces types de veines sont surifères par endroit mais l'apport initial de l'or date de la formation des veines parallèes à la stratification. L'absence de système de veines nourricières sinsi que la formation de fractures hydrauliques indiquent que les roches n'étalent pas perméables à l'époque de formation de veine et que le quartz et l'or sont de provenance locale. [Traduit par le journal

Improved throat inserts for ablative thrust chambers

Composite material development and structural design of improved throat inserts for ablative thrust chamber

Determination of scattering functions and their effects on remote sensing of turbidity in natural waters

The development of quantitative analytical procedures for relating scattered signals, measured by a remote sensor, was considered. The applications of a Monte Carlo simulation model for radiative transfer in turbid water are discussed. The model is designed to calculate the characteristics of the backscattered signal from an illuminated body of water as a function of the turbidity level, and the spectral properties of the suspended particulates. The optical properties of the environmental waters, necessary for model applications, were derived from available experimental data and/or calculated from Mie formalism. Results of applications of the model are presented

Variability in sonic-boom signatures measured along an 8000-foot linear array

Variability in sonic boom signatures measured along 8000 foot linear microphone arra

Cytokine gene polymorphisms in preterm infants with necrotising enterocolitis: genetic association study

BACKGROUND The inflammatory cytokine cascade is implicated in the pathogenesis of necrotising enterocolitis (NEC). Genetic association studies of cytokine polymorphisms may help to detect molecular mechanisms that are causally related to the disease process. AIM To examine associations between the common genetic variants in candidate inflammatory cytokine genes and NEC in preterm infants. METHODS Multi-centre case-control and genetic association study. DNA samples were collected from 50 preterm infants with NEC and 50 controls matched for gestational age and ethnic group recruited to a multi-centre case-control study. Ten candidate single-nucleotide polymorphisms in cytokines previously associated with infectious or inflammatory diseases were genotyped. The findings were included in random-effects meta-analyses with data from previous genetic association studies. RESULTS All allele distributions were in Hardy-Weinberg equilibrium. None of the studied cytokine polymorphisms was significantly associated with NEC. Four previous genetic association studies of cytokine polymorphisms and NEC in preterm infants were found. Meta-analyses were possible for several single-nucleotide polymorphisms. These increased the precision of the estimates of effect size but did not reveal any significant associations. CONCLUSIONS The available data are not consistent with more than modest associations between these candidate cytokine variant alleles and NEC in preterm infants. Data from future association studies of these polymorphisms may be added to the meta-analyses to obtain more precise estimates of effects sizes.The study was funded by Tenovus (Scotland)

DataWarp: Building Applications which Make Progress in an Inconsistent World

The usual approach to dealing with imperfections in data is to attempt to eliminate them. However, the nature of modern systems means this is often futile. This paper describes an approach which permits applications to operate notwithstanding inconsistent data. Instead of attempting to extract a single, correct view of the world from its data, a DataWarp application constructs a collection of interpretations. It adopts one of these and continues work. Since it acts on assumptions, the DataWarp application considers its recent work to be provisional, expecting eventually most of these actions will become definitive. Should the application decide to adopt an alternative data view, it may then need to void provisional actions before resuming work. We describe the DataWarp architecture, discuss its implementation and describe an experiment in which a DataWarp application in an environment containing inconsistent data achieves better results than its conventional counterpart

Is there Ornstein-Zernike equation in the canonical ensemble?

A general density-functional formalism using an extended variable-space is presented for classical fluids in the canonical ensemble (CE). An exact equation is derived that plays the role of the Ornstein-Zernike (OZ) equation in the grand canonical ensemble (GCE). When applied to the ideal gas we obtain the exact result for the total correlation function h_N. For a homogeneous fluid with N particles the new equation only differs from OZ by 1/N and it allows to obtain an approximate expression for h_N in terms of its GCE counterpart that agrees with the expansion of h_N in powers of 1/N.Comment: 5 pages, RevTeX. Submitted to Phys. Rev. Let

Derivation of a Non-Local Interfacial Hamiltonian for Short-Ranged Wetting II: General Diagrammatic Structure

In our first paper, we showed how a non-local effective Hamiltionian for short-ranged wetting may be derived from an underlying Landau-Ginzburg-Wilson model. Here, we combine the Green's function method with standard perturbation theory to determine the general diagrammatic form of the binding potential functional beyond the double-parabola approximation for the Landau-Ginzburg-Wilson bulk potential. The main influence of cubic and quartic interactions is simply to alter the coefficients of the double parabola-like zig-zag diagrams and also to introduce curvature and tube-interaction corrections (also represented diagrammatically), which are of minor importance. Non-locality generates effective long-ranged many-body interfacial interactions due to the reflection of tube-like fluctuations from the wall. Alternative wall boundary conditions (with a surface field and enhancement) and the diagrammatic description of tricritical wetting are also discussed.Comment: (14 pages, 2 figures) Submitted J. Phys. Condens. Matte

Assessment and Characterization of Physical Habitat, Water Quality, and Biotic Assemblages of the Tyronza River, Arkansas

Few studies within the last few decades have addressed water quality and biotic assemblages within Arkansas’s large channel-altered deltaic rivers. The Tyronza River is located in northeast Arkansas and its watershed has a heavy agricultural presence that drastically affects habitat quality. Meanwhile, the Tyronza River hosts one of the more recent documented range extensions of the federally endangered fat pocketbook mussel [Potamilus capax (Green, 1832)]. The purpose of this study was to assess physical habitat, water quality, and biotic assemblages of the Tyronza River using the Arkansas Department of Environmental Quality’s (ADEQ) regional biometrics. Water samples were collected at 9 stations across 4 seasonal intervals. Physical habitat, fish, and macroinvertebrates were collected at 9 stations during summer and fall. U.S. EPA Rapid Bioassessment Protocols for habitat indicated that habitat quality was suboptimal. Distinct seasonal differences were observed among all water chemistry parameters; however, seasonality was not as clear among nutrient constituents. Macroinvertebrate assemblages varied drastically among sites: taxa richness ranged from 3 to 14 and the Arkansas Macroinvertebrate Index for Small Watersheds values ranged from 16 to 28 (poor to very good condition). Fish Community Structure Indices were less variable among sites ranging from 6 to 16 (Not Similar to Somewhat Similar). The lack of instream habitat and habitat richness is likely resulting in low taxa richness in the biotic communities. Results from this study will provide managers and scientists with valuable information on seasonal variation of select water quality parameters and into the integrity of aquatic assemblages of the Tyronza River. Keywords: Water quality, rapi

Fluid structure in the immediate vicinity of an equilibrium three-phase contact line and assessment of disjoining pressure models using density functional theory

We examine the nanoscale behavior of an equilibrium three-phase contact line in the presence of long-ranged intermolecular forces by employing a statistical mechanics of fluids approach, namely density functional theory (DFT) together with fundamental measure theory (FMT). This enables us to evaluate the predictive quality of effective Hamiltonian models in the vicinity of the contact line. In particular, we compare the results for mean field effective Hamiltonians with disjoining pressures defined through (I) the adsorption isotherm for a planar liquid film, and (II) the normal force balance at the contact line. We find that the height profile obtained using (I) shows good agreement with the adsorption film thickness of the DFT-FMT equilibrium density profile in terms of maximal curvature and the behavior at large film heights. In contrast, we observe that while the height profile obtained by using (II) satisfies basic sum rules, it shows little agreement with the adsorption film thickness of the DFT results. The results are verified for contact angles of 20, 40 and 60 degrees