Classification of Static Plane Symmetric Spacetimes according to their Matter Collineations

In this paper we classify static plane symmetric spacetimes according to their matter collineations. These have been studied for both cases when the energy-momentum tensor is non-degenerate and also when it is degenerate. It turns out that the non-degenerate case yields either {\it four}, {\it five}, {\it six}, {\it seven} or {\it ten} independent matter collineations in which {\it four} are isometries and the rest are proper. There exists three interesting cases where the energy-momentum tensor is degenerate but the group of matter collineations is finite-dimensional. The matter collineations in these cases are either {\it four}, {\it six} or {\it tenComment: 15 pages, LaTex, no figure

Wave Properties of Plasma Surrounding the Event Horizon of a Non-Rotating Black Hole

We have studied the wave properties of the cold and isothermal plasma in the vicinity of the Schwarzschild black hole event horizon. The Fourier analyzed perturbed 3+1 GRMHD equations are taken on the basis of which the complex dispersion relations are obtained for non-rotating, rotating non-magnetized and rotating magnetized backgrounds. The propagation and attenuation vectors along with the refractive index are obtained (shown in graphs) to study the dispersive properties of the medium near the event horizon. The results show that no information can be obtained from the Schwarzschild magnetosphere. Further, the pressure ceases the existence of normal dispersion of waves.Comment: 31 pages, 21 figures, accepted for publication in Canadian J. Phy

Effect of geochemical processes and environment on the spatial pattern of selenium in soil, surface water, and groundwater at the Hovland Ranch, central South Dakota

The objective of this paper is to test and review some of the published hypotheses as that may relate to selenium geochemistry in soil and water system at the Hovland Ranch, Haakon County, South Dakota. Representative samples were collected from soil, water, and soil moisture in the field. Preparation of samples and chemical analysis were done in the Water Quality Laboratory, Dept. of Geology and Geological Engineering, University of North Dakota and Human Nutrition Research Center Lab, USDA/ARS, Grand Forks, North Dakota. The analysis results were statistically analyzed to find correlation between the occurrence of selenium and other associated chemical elements in the soil and water system in the ranch area. Both total and water soluble selenium in the soil and water samples is significantly positively correlated to sodium, sulfate, and phosphorus. Water soluble selenium is mostly selenate. Selenite is below detection limit in the water soluble extracts of soils. Very little total selenium is water soluble, with an average of only 2%. Selenium is significantly positively correlated to arsenic in both water soluble and acid extracted soil extraction and soil moisture samples. Total organic maintains a positive correlation with selenium. Selenium in the water and soil moisture samples is positively correlated to electrical conductance. Nitrate-nitrogen shows positive correlation with selenium in soil extracts, but the correlation is negative for water and soil moisture samples. Calcium has very little or no correlation with selenium in both the soil (water soluble extracts) and water samples. But calcium has positive correlation with selenium in the acid extracted soil samples. Total selenium maintains no correlation with depth. Water soluble selenium shows poor but significant negative correlation with depth. Water soluble selenium shows poor but positive correlation with elevation. Total selenium has very little spatial variation over the area with insignificant standard deviation, but the spatial distribution of water soluble selenium is distinct with high standard deviation. All the chemical analysis data suggest that sodium, magnesium and sulfate minerals create a major geochemical sink for water soluble selenium. The solubility of these salts may be the principal factor controlling the mobility and transport of selenium in the soil-water environment

Classification of Spherically Symmetric Static Spacetimes according to their Matter Collineations

The spherically symmetric static spacetimes are classified according to their matter collineations. These are studied when the energy-momentum tensor is degenerate and also when it is non-degenerate. We have found a case where the energy-momentum tensor is degenerate but the group of matter collineations is finite. For the non-degenerate case, we obtain either {\it four}, {\it five}, {\it six} or {\it ten} independent matter collineations in which four are isometries and the rest are proper. We conclude that the matter collineations coincide with the Ricci collineations but the constraint equations are different which on solving can provide physically interesting cosmological solutions.Comment: 15 pages, no figure, Late

Adoption and impacts of zero tillage as a resource conserving technology in the irrigated plains of South Asia

Zero tillage / Rice / Wheat / Water conservation / India / Pakistan / Haryana / Punjab

Dynamics of Non-adiabatic Charged Cylindrical Gravitational Collapse

This paper is devoted to study the dynamics of gravitational collapse in the Misner and Sharp formalism. We take non-viscous heat conducting charged anisotropic fluid as a collapsing matter with cylindrical symmetry. The dynamical equations are derived and coupled with the transport equation for heat flux obtained from the M$\ddot{u}$ller-Israel-Stewart causal thermodynamic theory. We discuss the role of anisotropy, electric charge and radial heat flux over the dynamics of the collapse with the help of coupled equation.Comment: 15 pages, accepted for publication in Astrophys. Space Sc

Gravitational Collapse: Expanding and Collapsing Regions

We investigate the expanding and collapsing regions by taking two well-known spherically symmetric spacetimes. For this purpose, the general formalism is developed by using Israel junction conditions for arbitrary spacetimes. This has been used to obtain the surface energy density and the tangential pressure. The minimal pressure provides the gateway to explore the expanding and collapsing regions. We take Minkowski and Kantowski-Sachs spacetimes and use the general formulation to investigate the expanding and collapsing regions of the shell.Comment: 12 pages, 4 figures, accepted for publication in Gen. Relativ. Gra

Semantic-Based Process Mining Technique for Annotation and Modelling of Domain Processes

Semantic technologies aim to represent information or models in formatsthat are not just machine-readable but also machine-understandable. To this effect, thispaper shows how the semantic concepts can be layered on top of the derived models toprovide a more contextual analysis of the models through the conceptualization method.Technically, the method involves augmentation of informative value of the resulting mod-els by semantically annotating the process elements with concepts that they represent inreal-time settings, and then linking them to an ontology in order to allow for a moreabstract analysis of the extracted logs or models. The work illustrates the method usingthe case study of a learning process domain. Consequently, the results show that a systemwhich is formally encoded with semantic labelling (annotation), semantic representation(ontology) and semantic reasoning (reasoner) has the capacity to lift the process miningand analysis from the syntactic to a more conceptual level

Prevalence of helminthic infection among primary school children in some selected primary schools in municipal local government area, Kano state, Nigeria

The research was conducted to study the prevalence of helminthic infection among primary school children in some selected primary schools in municipal   local government area, Kano state. A total of 100 hundred school children between the ages group of 6-12 years old were examined for intestinal helminth infections using direct wet method and formol-ether concentration technique. The samples were collected from both sexes and were processed. Of the 100 pupils examined, 72.0% were infected with one or a combination of the worms with Ascaris having the highest prevalence rate (31.0%) followed by hookworm (19.0%), Schistosoma (8.0%), Enterobius (8.0%), Strongyloides (6.0%) had the least rate of infection as shown in table 3. The prevalence of infection of helminth parasite among schools ranged between (A) 17(23.62%), (B) 14(19.4%), (C) 12(16.67%), (D) 15(20.83%), and (E) 14(19.44%) with no significant  difference in the prevalence of infection between schools (p>0.05). Table 1 shows that out of 100 pupils examined, 40(40.0%) males and 60(60.0%) females respectively, of these 27(67.5%) males and 45(75.0) females were infected, the difference not significant (p>0.05). Of the 72 infected subject 17(23.6%) have multiple infection with 11(15.3%) and 6(8.4%) having double and triple infections respectively. Ascaris occur mostly with other helminth, Ascaris lumbricoides+ hookworm and Ascaris +enterobius vermicularis+ hookworm mostly were more common occurring combinations.         

Electrodynamics in Friedmann-Robertson-Walker Universe: Maxwell and Dirac fields in Newman-Penrose formalism

Maxwell and Dirac fields in Friedmann-Robertson-Walker spacetime is investigated using the Newman-Penrose method. The variables are all separable, with the angular dependence given by the spin-weighted spherical harmonics. All the radial parts reduce to the barrier penetration problem, with mostly repulsive potentials representing the centrifugal energies. Both the helicity states of the photon field see the same potential, but that of the Dirac field see different ones; one component even sees attractive potential in the open universe. The massless fields have the usual exponential time dependencies; that of the massive Dirac field is coupled to the evolution of the cosmic scale factor $a$. The case of the radiation filled flat universe is solved in terms of the Whittaker function. A formal series solution, valid in any FRW universe, is also presented. The energy density of the Maxwell field is explicitly shown to scale as $a^{-4}$. The co-moving particle number density of the massless Dirac field is found to be conserved, but that of the massive one is not. Particles flow out of certain regions, and into others, creating regions that are depleted of certain linear and angular momenta states, and others with excess. Such current of charged particles would constitute an electric current that could generate a cosmic magnetic field. In contrast, the energy density of these massive particles still scales as $a^{-4}$.Comment: 18 pages including 9 figure