849 research outputs found

    Geophysical Analysis of Basement Terrain Groundwater Using Vertical Electrical Sounding: A Case Study of Parts of Abuja North Central Nigeria

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    The successful exploitation of groundwater requires a proper understanding of the hydrogeological characteristics of the sub-surface aquifers found within the basement complex. This can be carried out using various geophysical survey methods. Groundwater occurs in the joints, fissures, fractures, shear zones and weathered overburden of un-weathered rocks. Therefore effective groundwater development requires careful geophysical analysis and interpretation of data. The use of vertical electrical sounding (VES) for groundwater (hydrogeological) exploration is popular in the basement complex rocks and sedimentary basins. This study was aimed at analysing the hydro geological characteristics such as bedrock depth, lithological units and degree of fracturing and drilling location of groundwater in the basement complex / terrain of Garki, Kurudu, Dei-Dei and Kubwa areas of Abuja, North central Nigeria using Resistivity Method. Finally, the results indicate that the choice of geophysical survey method determined by physical properties of the area; influence groundwater availability, susceptibility and supply

    Geophysical Analysis of Basement Terrain Groundwater Using Vertical Electrical Sounding: A Case Study of Parts of Abuja North Central Nigeria

    Get PDF
    The successful exploitation of groundwater requires a proper understanding of the hydrogeological characteristics of the sub-surface aquifers found within the basement complex. This can be carried out using various geophysical survey methods. Groundwater occurs in the joints, fissures, fractures, shear zones and weathered overburden of un-weathered rocks. Therefore effective groundwater development requires careful geophysical analysis and interpretation of data. The use of vertical electrical sounding (VES) for groundwater (hydrogeological) exploration is popular in the basement complex rocks and sedimentary basins. This study was aimed at analysing the hydro geological characteristics such as bedrock depth, lithological units and degree of fracturing and drilling location of groundwater in the basement complex / terrain of Garki, Kurudu, Dei-Dei and Kubwa areas of Abuja, North central Nigeria using Resistivity Method. Finally, the results indicate that the choice of geophysical survey method determined by physical properties of the area; influence groundwater availability, susceptibility and supply

    Method of Monte Carlo grid for data analysis

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    This paper presents an analysis procedure for experimental data using theoretical functions generated by Monte Carlo. Applying the classical chi-square fitting procedure for some multiparameter systems is extremely difficult due to a lack of an analytical expression for the theoretical functions describing the system. The proposed algorithm is based on the least square method using a grid of Monte Carlo generated functions each corresponding to definite values of the minimization parameters. It is used for the E742 experiment (TRIUMF, Vancouver, Canada) data analysis with the aim to extract muonic atom scattering parameters on solid hydrogen.Comment: 16 pages, 10 figures, submitted to NI

    Volume Comparison for Hypersurfaces in Lorentzian Manifolds and Singularity Theorems

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    We develop area and volume comparison theorems for the evolution of spacelike, acausal, causally complete hypersurfaces in Lorentzian manifolds, where one has a lower bound on the Ricci tensor along timelike curves, and an upper bound on the mean curvature of the hypersurface. Using these results, we give a new proof of Hawking's singularity theorem.Comment: 15 pages, LaTe

    A Sublinear Variance Bound for Solutions of a Random Hamilton Jacobi Equation

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    We estimate the variance of the value function for a random optimal control problem. The value function is the solution wϵw^\epsilon of a Hamilton-Jacobi equation with random Hamiltonian H(p,x,ω)=K(p)V(x/ϵ,ω)H(p,x,\omega) = K(p) - V(x/\epsilon,\omega) in dimension d2d \geq 2. It is known that homogenization occurs as ϵ0\epsilon \to 0, but little is known about the statistical fluctuations of wϵw^\epsilon. Our main result shows that the variance of the solution wϵw^\epsilon is bounded by O(ϵ/logϵ)O(\epsilon/|\log \epsilon|). The proof relies on a modified Poincar\'e inequality of Talagrand

    The wave equation on singular space-times

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    We prove local unique solvability of the wave equation for a large class of weakly singular, locally bounded space-time metrics in a suitable space of generalised functions.Comment: Latex, 19 pages, 1 figure. Discussion of class of metrics covered by our results and some examples added. Conclusion more detailed. Version to appear in Communications in Mathematical Physic

    Guidelines on the use of Structure from Motion Photogrammetry in Geomorphic Research

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    As a topographic modelling technique, structure-from-motion (SfM) photogrammetry combines the utility of digital photogrammetry with a flexibility and ease of use derived from multi-view computer vision methods. In conjunction with the rapidly increasing availability of imagery, particularly from unmanned aerial vehicles, SfM photogrammetry represents a powerful tool for geomorphological research. However, to fully realize this potential, its application must be carefully underpinned by photogrammetric considerations, surveys should be reported in sufficient detail to be repeatable (if practical) and results appropriately assessed to understand fully the potential errors involved. To deliver these goals, robust survey and reporting must be supported through (i) using appropriate survey design, (ii) applying suitable statistics to identify systematic error (bias) and to estimate precision within results, and (iii) propagating uncertainty estimates into the final data products

    Guidelines on the use of Structure from Motion Photogrammetry in Geomorphic Research

    Get PDF
    As a topographic modelling technique, structure-from-motion (SfM) photogrammetry combines the utility of digital photogrammetry with a flexibility and ease of use derived from multi-view computer vision methods. In conjunction with the rapidly increasing availability of imagery, particularly from unmanned aerial vehicles, SfM photogrammetry represents a powerful tool for geomorphological research. However, to fully realize this potential, its application must be carefully underpinned by photogrammetric considerations, surveys should be reported in sufficient detail to be repeatable (if practical) and results appropriately assessed to understand fully the potential errors involved. To deliver these goals, robust survey and reporting must be supported through (i) using appropriate survey design, (ii) applying suitable statistics to identify systematic error (bias) and to estimate precision within results, and (iii) propagating uncertainty estimates into the final data products

    Association and interaction analyses of eight genes under asthma linkage peaks

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    Background: Linkage studies have implicated the 2q33, 9p21, 11q13 and 20q13 regions in the regulation of allergic disease. The aim of this study was to test genetic variants in candidate genes from these regions for association with specific asthma traits. Methods: Ninety-five single nucleotide polymorphisms (SNP) located in eight genes (CD28, CTLA4, ICOS, ADAM23, ADAMTSL1, MS4A2, CDH26 and HRH3) were genotyped in >5000 individuals from Australian (n = 1162), Dutch (n = 99) and Danish (n = 303) families. Traits tested included doctor-diagnosed asthma, atopy, airway obstruction, total serum immunoglobulin (Ig) E levels and eosinophilia. Association was tested using both multivariate and univariate methods, with gene-wide thresholds for significance determined through simulation. Gene-by-gene and gene-by-environment analyses were also performed. Results: There was no overall evidence for association with seven of the eight genes tested when considering all genetic variation assayed in each gene. The exception was MS4A2 on chromosome 11q13, which showed weak evidence for association with IgE (gene-wide P < 0.05, rs502581). There were no significant gene-by-gene or gene-by-environment interaction effects after accounting for the number of tests performed. Conclusions: The individual variants genotyped in the 2q33, 9p21 and 20q13 regions do not explain a large fraction of the variation in the quantitative traits tested or have a major impact on asthma or atopy risk. Our results are consistent with a weak effect of MS4A2 polymorphisms on the variation of total IgE levels. © 2009 John Wiley & Sons A/S
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