On the EDM Cancellations in D-brane models

We analyze the possibility of simultaneous electron, neutron, and mercury electric dipole moment (EDM) cancellations in the mSUGRA and D--brane models. We find that the mercury EDM constraint practically rules out the cancellation scenario in D-brane models whereas in the context of mSUGRA it is still allowed with some fine-tuning.Comment: 10 pages, to appear in Phys. Rev. Let

Assessment of people’s knowledge and perceptions of vultures in some selected areas of Plateau state Nigeria and its conservation implications

The study was conducted to assess the perceptions, beliefs, knowledge and attitudes of people toward vultures. Four study sites from three local government areas in Jos were selected. Methods included the use of open ended, semi-structured questionnaires. Respondents were selected using stratified random sampling and purposive sampling. A hundred and sixty respondents participated in the study. Results revealed that the most seen and identified vulture species was the Hooded Vulture Necrosyrte monarchus 83(51.9%). Respondents’knowledge of what vultures eat and where they can be found showed varied knowledge among respondents. Respondents also thought that vultures had declined but could not link the decline to any human activity. Seventy-five (46.9%) of the respondents had negative perceptions of vultures, while 57(35.6%) had positive perceptions. Local beliefs about vultures revealed that vultures where perceived as evil by 38(23.7%) of the respondents. Knowledge of vulture importance in the environment was low, 77(48.1%) perceived vultures as not important while 72(45.0%) thought them important. Perception and knowledge about vultures was seen to affect the willingness of respondents to protect vultures. We conclude that knowledge and perceptions about Vultures is low, and might be related to the low sightings and interactions with the species due to the decline in vulture populations. We suggest that education and awareness programs and campaigns need to be intensified among the public to end Vulture persecution and decline Keywords: Perception, Attitude, Vulture, Biodiversity, Conservatio

Preliminary study on the concentration of some heavy metals around a proposed cement factory in Kogi State Nigeria

The analysis of soils from a cement mine site and the surrounding farmland for Ni, Pb, Co and Cd at different depths show concentrations that are generally below the maximum acceptable limits for land applications. Observed mean concentrations at the mine site are 0.3367 mg/kg, 0.1982 mg/kg and 0.1100 mg/kg for Ni, Pb and Co respectively. Cd was not detected. The observed mean concentrations in the surrounding farmland are 0.3800 mg/kg, 0.1705 mg/kg, 0.1143 mg/kg and 0.0064 mg/kg for Ni, Pb,  Co and Cd respectively. Thus the mine site land was not suspected to contributing to the heavy metal content in the agricultural land. The results obtained could act as a benchmark for future determinations on same study area when mining activities eventually commences. © 2013 International Formulae Group. All rights reserved.Keywords: FAAS, Heavy metals, cement, mine soil, agricultural land

Unitarity analysis of general Born-Infeld gravity theories

We develop techniques of analyzing the unitarity of general Born-Infeld (BI) gravity actions in D-dimensional spacetimes. Determinantal form of the action allows us to find a compact expression quadratic in the metric fluctuations around constant curvature backgrounds. This is highly nontrivial since for the BI actions, in principle, infinitely many terms in the curvature expansion should contribute to the quadratic action in the metric fluctuations around constant curvature backgrounds, which would render the unitarity analysis intractable. Moreover in even dimensions, unitarity of the theory depends only on finite number of terms built from the powers of the curvature tensor. We apply our techniques to some four-dimensional examples.Comment: 26 pages, typos corrected, version to appear in Phys. Rev.

Surface Electronic Structures and Field Emission Currents at Sodium Overlayers on Low-Index Tungsten Surfaces

The total energy distributions (TEDs) of the emission currents in field emission and surface photofield emission and the overlayer-induced modifications in the surface electronic structures from the technologically important W surfaces with the commensurate W(100)/Na c(2x2), W(110)/Na (2x2) and W(111)/Na (1x1) overlayers are calculated. The TEDs obtained by our recent numerical method that extends the full-potential linear augmented plane wave method for the electronic structures to the study of field and photofield emission are used to interpret the shifts of the peaks in the experimental TEDs in field emission and photofield emission from the W(100) and W(110) surfaces at sub-monolayer and monolayer Na coverage. Hybridization of the 3s Na states with the pairs of dz2-like surface states of the strong Swanson hump in clean W(100) and surface resonances in clean W(111) below the Fermi energy shifts these W states by about -1.2 eV and -1.0 eV, thus stabilizing these states, to yield new strong peaks in the TEDs in field emission and photofield emission from W(100)/Na c(2x2) and W(111)/Na (1x1) respectively. The effect of Na intralayer interactions are discussed and are shown to shift the strong s- and p-like peaks in the surface density of states of W(110) below and above the Fermi energy respectively to lower energy with increased Na coverage, in agreement with experiments.Comment: 12 page

Relaxation of the Dynamical Gluino Phase and Unambiguous Electric Dipole Moments

We propose a new axionic solution of the strong CP problem with a Peccei-Quinn mechanism using the gluino rather than quarks. The spontaneous breaking of this new global U(1) at 10^{11} GeV also generates the supersymmetry breaking scale of 1 TeV (solving the so-called \mu problem at the same time) and results in the MSSM (Minimal Supersymmetric Standard Model) with R parity conservation. In this framework, electric dipole moments become calculable without ambiguity.Comment: Typos corrected and a footnote added, 10 p

CP violating asymmetries in single top quark production at the Tevatron p pbar collider

Analytic expressions for the angular distributions of the $b$-quarks associated with single $t$-quark production in $p \bar p \to W^* \to t \bar b \to b \bar b W$ and of the leptons from the subsequent decay $W \to l\nu$ are obtained in the laboratory system. CP violation in the $t$-production vertex is assumed. Different angular and total cross section CP violating asymmetries are considered. Relations testing CP violation solely in the $t$-decay vertex are also obtained. A numerical analysis is performed in the MSSM with a CP violating phase of the trilinear coupling $A_{\tilde t}$. The asymmetries are typically of the order $10^{-3}$ - $10^{-4}$.Comment: The numerical results are corrected and some changes that meet the requirements of Phys. Rev. D are mad

Mixing of the CP Even and the CP Odd Higgs Bosons and the EDM Constraints

The mixing among the CP even and the CP odd neutral Higgs bosons of MSSM by one loop induced effects in the presence of CP phases is investigated using three different mechanisms to satisfy the EDM constraints, i.e., a fine tuning of phases, a heavy sparticle spectrum, and the cancellation mechanism. It is shown that if a mixing effect among the CP even and the CP odd Higgs bosons is observed experimentally, then it is only the cancellation mechanism that can survive under the naturalness constraint.Comment: 14 pages, Latex and 4figures. A new paragraph is added and few more references. One figure is modified. To appear in Phys. Rev.