Impact of vehicular traffic on ambient air quality in selected junctions in Port Harcourt, Nigeria

The increase in the vehicle population in Port Harcourt associated with increase in economic activities has left a scar in ambient air quality. This study investigated the impact of vehicular traffic in selected junction of Port Harcourt city. Air quality survey was conducted using standard analytical protocols Anemometer, and multi-purpose air quality analyzers. The generated results showed that PM2.5 and PM 10 at Garrison, Isaac Boro park, Lagos Bus stop and control were above NAAQS limit of 35.0μg/m3 and 150.0μg/m3 respectively. Total suspended particulate matter (TSPM) in Garrison, and Lagos Bus stop were 208.0μg/m3, and 398.53μg/m3 which were above NAAQS limit of 200.0μg/m3. The other measured parameter including hydrocarbons, CO, N2O, S2O were above NAAQS and FMEnv signifying that the ambient air around study areas were polluted. Results of a 2-way analysis of variance (ANOVA) indicated that there was no significant difference at respective sampling locations; but for individual pollutant characteristics there were significant differences at p<0.05. Cumulative effects under prolong exposure may result in various chronic health challenges. The study recommended that government should establish vehicular integrity and emission testing centers in Port Harcourt City to reduce air pollution.Keywords: Ambient, Air Quality, Emission, Chronic, Vehicular, Pollutio

Astrophysical Implications of the Induced Neutrino Magnetic Moment from Large Extra Dimensions

Theories involving extra dimensions, a low (TeV) string scale and bulk singlet neutrinos will produce an effective neutrino magnetic moment which may be large (< 10^{-11} mu_B). The effective magnetic moment increases with neutrino energy, and therefore high energy reactions are most useful for limiting the allowed number of extra dimensions. We examine constraints from both neutrino-electron scattering and also astrophysical environments. We find that supernova energy loss considerations require a number of extra dimensions, n > 1, for an electron neutrino-bulk neutrino Yukawa coupling of order 1.Comment: 12 pages, 3 figures, figure added, references adde

New insight on pseudospin doublets in nuclei

The relevance of the pseudospin symmetry in nuclei is considered. New insight is obtained from looking at the continuous transition from a model satisfying the spin symmetry to another one satisfying the pseudospin symmetry. This study suggests that there are models allowing no missing single-particle states in this transition, contrary to what is usually advocated. It rather points out to an association of pseudospin partners different from the one usually assumed, together with a strong violation of the corresponding symmetry. A comparison with results obtained from some relativistic approaches is made.Comment: 27 pages, 18 figure

Spin symmetry in Dirac negative energy spectrum in density-dependent relativistic Hartree-Fock theory

The spin symmetry in the Dirac negative energy spectrum and its origin are investigated for the first time within the density-dependent relativistic Hartree-Fock (DDRHF) theory. Taking the nucleus $^{16}$O as an example, the spin symmetry in the negative energy spectrum is found to be a good approximation and the dominant components of the Dirac wave functions for the spin doublets are nearly identical. In comparison with the relativistic Hartree approximation where the origin of spin symmetry lies in the equality of the scalar and vector potentials, in DDRHF the cancellation between the Hartree and Fock terms is responsible for the better spin symmetry properties and determines the subtle spin-orbit splitting. These conclusions hold even in the case when significant deviations from the G-parity values of the meson-antinucleon couplings occur.Comment: 13 pages, 7 figures, 1 table, accepted by Eur. Phys. J.

Lepton masses in a supersymmetric 3-3-1 model

We consider the mass generation for both charginos and neutralinos in a 3-3-1 supersymmetric model. We show that R-parity breaking interactions leave the electron and one of the neutrinos massless at the tree level. However the same interactions induce masses for these particles at the 1-loop level. Unlike the similar situation in the MSSM the masses of the neutralinos are related to the masses of the charginos.Comment: RevTex, 11 pages incluing 2 .eps figures. Extended published versio

Novel gonadal characteristics in an aged bovine freemartin

The gonads from a five year old freemartin Holstein animal were subjected to morphological analysis and to immunohistochemistry using antibodies against developmental and functional markers. We demonstrate, for the first time, the retention of anti-mullerian hormone (AMH) producing intratubular cells (Sertoli cells) in the context of abundant steroidogenic interstitial cells, and structures consistent with clusters of luteal cells. This novel report describes the clinical, gross and histological findings accompanying this newly described gonadal immunophenotype, and its implication in the understanding of freemartin development

Energy Level Statistics of the U(5) and O(6) Symmetries in the Interacting Boson Model

We study the energy level statistics of the states in U(5) and O(6) dynamical symmetries of the interacting boson model and the high spin states with backbending in U(5) symmetry. In the calculations, the degeneracy resulting from the additional quantum number is eliminated manually. The calculated results indicate that the finite boson number $N$ effect is prominent. When $N$ has a value close to a realistic one, increasing the interaction strength of subgroup O(5) makes the statistics vary from Poisson-type to GOE-type and further recover to Poisson-type. However, in the case of $N \to \infty$, they all tend to be Poisson-type. The fluctuation property of the energy levels with backbending in high spin states in U(5) symmetry involves a signal of shape phase transition between spherical vibration and axial rotation.Comment: 38 pages, 13 figure

Azimuthal anisotropy and correlations in p+p, d+Au and Au+Au collisions at 200 GeV

We present the first measurement of directed flow ($v_1$) at RHIC. $v_1$ is found to be consistent with zero at pseudorapidities $\eta$ from -1.2 to 1.2, then rises to the level of a couple of percent over the range $2.4 < |\eta| < 4$. The latter observation is similar to data from NA49 if the SPS rapidities are shifted by the difference in beam rapidity between RHIC and SPS. Back-to-back jets emitted out-of-plane are found to be suppressed more if compared to those emitted in-plane, which is consistent with {\it jet quenching}. Using the scalar product method, we systematically compared azimuthal correlations from p+p, d+Au and Au+Au collisions. Flow and non-flow from these three different collision systems are discussed.Comment: Quark Matter 2004 proceeding, 4 pages, 3 figure

Azimuthal anisotropy: the higher harmonics

We report the first observations of the fourth harmonic (v_4) in the azimuthal distribution of particles at RHIC. The measurement was done taking advantage of the large elliptic flow generated at RHIC. The integrated v_4 is about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8) harmonics upper limits on the magnitudes are reported.Comment: 4 pages, 6 figures, contribution to the Quark Matter 2004 proceeding

All-optical switching and strong coupling using tunable whispering-gallery-mode microresonators

We review our recent work on tunable, ultrahigh quality factor whispering-gallery-mode bottle microresonators and highlight their applications in nonlinear optics and in quantum optics experiments. Our resonators combine ultra-high quality factors of up to Q = 3.6 \times 10^8, a small mode volume, and near-lossless fiber coupling, with a simple and customizable mode structure enabling full tunability. We study, theoretically and experimentally, nonlinear all-optical switching via the Kerr effect when the resonator is operated in an add-drop configuration. This allows us to optically route a single-wavelength cw optical signal between two fiber ports with high efficiency. Finally, we report on progress towards strong coupling of single rubidium atoms to an ultra-high Q mode of an actively stabilized bottle microresonator.Comment: 20 pages, 24 figures. Accepted for publication in Applied Physics B. Changes according to referee suggestions: minor corrections to some figures and captions, clarification of some points in the text, added references, added new paragraph with results on atom-resonator interactio