Technology for constructing a 3D density model of the earth's crust in the INTEGRO GIS

The work is devoted to the construction of a three-dimensional density model of the territory, which would not contradict the information obtained by other methods (drilling, seismic, etc.). A generalized scheme for constructing such a model is given, its stages and ways of matching with the results of other methods are described. The technology described in the work is based on the tools included in the GIS INTEGRO software package (FSBI "VNIGNI"). The article is illustrated with examples of the technology application in the construction of density models for various parts of the Volga-Ural oil and gas province. Key words: density modeling, 3D density model, inverse problem of gravity exploration, GIS INTEGRO.

Density and diversity of birds in the wetlands of Yankari Game Reserve Bauchi Nigeria

The biological, chemical, and physical operations and attributes of wetlands are vital in facilitating food resources, water, and shelter, which many terrestrial bird and waterbird species rely on for their daily requirments. Wetlands in Yankari Game Reserve, Nigeria are key stone ecosystem that provides a stopover, breeding and/or foraging platform for migratory and resident birds. This study determined the density and diversity of birds in the wetlands of Yankari Game Reserve. Ten wetlands within the reserve were identified and surveyed. The sizes (kilometer square) and isolation distances (kilometer) of the wetlands were measured (using GPS and Map Source) to determine their effects on bird density and diversity. Point count survey method was used to count birds. One hundred and twenty three species of birds belonging to 51 families were recorded in the wetlands. Significant patterns in the densities of birds were observed across the wetlands (Kruskal-Wallis H, X2=167.116, P=0.001) and also sizes of wetlands (Wilcoxon test: Z= -2.803, P=0.005). There was differences in mean number of birds in survey time (Kruskal-Wallis, X2=15.784, P=0.045). Evenings were probably most preferred in bird-wetland utilization. Key words: Density; Diversity; Yankari ecosystem; Wetland utilization DOI: http://dx.doi.org/10.3126/jowe.v5i0.4778 J Wet Eco 2011 (5): 48-58

Approximate kinetic energy density functionals generated by local-scaling transformations

Different stages in the development of density functional theory are succinctly reviewed for the purpose of tracing the origin of the local-scaling transformation version of density functional theory. Explicit kinetic energy functionals are generated within this theory. These functionals are analyzed in terms of several approximations to the local-scaling function and are applied to a few selected first-row atoms. Key words: density functional theory, kinetic energy density functionals, local-scaling transformations, explicit kinetic energy functionals, kinetic energy of first-row atoms.

Current-density dependent exchange-correlation functionals

Previous models for exchange (Becke and Roussel, Phys. Rev. A: 39, 3761 (1989)) and for correlation (Becke, J. Chem. Phys. 88, 1053 (1988)) are, in a simple and natural way, generalized to include explicit dependence on current density J. First-principles incorporation of J into exchange-correlation density functionals, as proposed here, is crucial for further progress in the study of magnetic effects in density-functional theory. Key words: density-functional theory, exchange-correlation functionals, current density.

An experimental study of the role of seedling density and neighbor relatedness in the persistence of Rumex acetosella in an old-field succession

Patterns in flowering and biomass allocation in seedlings of Rumex acetosella L. collected from five successional old fields, from 1 year old to 15 years old, have been examined in experimental pots varying in density (1, 2, and 4 plants/pot) and neighbor relatedness (sib, nonsib, other population) to determine the effects of successional habitat variation on patterns of resource allocation. The flowering of seedlings from the successionally young populations was not affected by density, whereas for seedlings from the older populations, increased density was correlated with increased variation in flower and seed production both within and between populations. At high density, seedlings from the successionally youngest population showed the greatest allocation of resources to flowering. As a result, differentiation along the successional gradient was such that the younger populations invested a greater proportion of resources to aerial biomass, while the older populations allocated relatively more resources to vegetative propagation. These trends were maintained at high density. The results of the sibling competition treatment showed no consistent trend related to the age of the populations but were density dependent. At high density, sexual biomass was higher between nonsibs than between sibs of the same population, suggesting greater competition among related plants. Finally, the sexual biomass of individual plants was less in competition with seedlings from a different population than with seedlings from the same population. Sprout biomass showed the reverse trend. The observed differentiation between successionally different populations in resource allocation irrespective of density may account for these results. Overall, our results provide evidence for biotic specialization of R. acetosella in relation to successional habitat change. Key words: density, sibling competition, succession, trade-off, Rumex acetosella, resource allocation.

The influence of plant density on flower, fruit, and leaf demography in bush bean, Phaseolus vulgaris

The influence of plant population density on bush beans is analyzed in terms of its effect on flower, fruit, and leaf demography, biomass, and yield. Plants grown at the lowest density (solitary plants) did best in terms of leaf production, total leaf days, flowers, and production of marketable pods (i.e., having at least one seed). These plants also accumulated more biomass and had greater numbers of all components of yield. In addition, they showed greater proportionate allocation to reproduction. In all density treatments the second flower cohort (produced 33–35 days after seeds were sown) made the greatest contribution to yield (43–78%). When flower production began, the rate of leaf initiation declined; leaf mortality seemed coupled to the onset of fruit production and was most severe in plants that had many pods to mature. The probability that flowers produced under any density regime would become pods and that these pods in turn would become marketable pods was assessed. Pod production was broken down into two stages: the transition from flower to fruit and from fruit to marketable pod. The results suggest that the transition from flower to fruit is not resource-limited, but the transition from fruit to marketable pod is dependent on current resource supply. When the data are examined on a per pot basis, plants at the highest density were most productive in terms of nonproductive tissues. However, an intermediate density (equivalent to 200 plants/m2) produced the greatest total reproductive biomass and the greatest number of marketable pods per unit area. The value of leaf and flower demography as measures of uniformity of maturation, optimal planting density, and cultivar performance is discussed. Key words: density, flower demography, fruit demography, leaf demography, Phaseolus vulgaris, yield.

Excess molar volumes and excess viscosities of n-butylamine + 1,4-dioxane + carbon tetrachloride system at 298.15 K

Densities and viscosities were determined for the n-butylamine + 1,4-dioxane + carbon tetrachloride system at 298.15 K. Molar excess volumes and excess viscosities were calculated from the experimental results. Analytical expressions can be used to predict these excess properties from binary data, the empirical correlation of Cibulka being the best for this system. Key words: density; mixture of n-butylamine + 1,4-dioxane + carbon tetrachloride; viscosity, mixture of n-butylamine + 1,4-dioxane + carbon tetrachloride; excess properties of ternary mixture.

The structure of the CC1n− (n = 1–4) anions and electronic affinities of the corresponding neutrals

Electronic and geometrical structures for the ground states of the singly charged anions CCln−, n = 1–4, and Clm−, m = 2, 3, as well as the corresponding neutral species have been studied by Approximate Density Functional Theory (DFT). A full geometry optimization has been carried out on both anionic and neutral species. Vertical and adiabatic electron affinities were evaluated for the neutral species along with an estimate of the first ionization potential (FIP) for the anions. A discussion is given of the different dissociation channels for CCl4−. It follows from the present set of calculations that the anion CCl4− is non-rigid with a global minima corresponding to an elongated tetrahedron of C3v symmetry. Key words: Density Function Theory, electronic affinities.

Impact resistance of three soils under varying moisture and subzero temperature conditions

Impact resistance, the deceleration-time response of a moving body upon impact with a surface, can be used to measure the hardness of a soil surface. A simple method for measuring impact resistance is presented. Impact resistance of three soils (Preston sand, Haldimand clay, and Guelph loam) was measured over a range of moisture and subzero temperature conditions. Impact resistance of frozen soil was found to increase with increasing moisture content, decreasing temperature, and increasing particle diameter. Temperature effects on impact resistance were minimal below −4 °C. Under field conditions, increased impact resistance due to increased particle diameter may be compensated for by reduced moisture content. Key words: density, dynamic loading, grain size, soil strength, sports fields.

Testing for Density-Dependent Marine Survival in Pacific Salmonids

Marine survival data for several different salmonid stocks were reviewed to determine whether there was significant density-dependent survival occurring in the ocean. Four classes of interaction were examined: (1) within-cohorts, (2) between-cohorts, (3) between stocks on the same or nearby rivers, and (4) between stocks of distant rivers. Results of statistical tests indicate that some stocks do not produce an increase in adult returns with increased smolt abundance, and that marine survival rate of other stocks is affected by abundance of other cohorts or stocks. Only a few stocks exhibit these density-dependent relations, but given present data, it is impossible to predict the frequency of occurrence of such limiting processes in future enhanced stocks. Salmonid enhancement planning is discussed in the context of this uncertainty and experimental enhancement projects are suggested that aim to obtain information about marine survival processes as well as additional catches. Key words: density dependent, marine survival, salmonids, experimental enhancement, stock interaction, adaptive