Dynamics of a Charged Particle Around a Slowly Rotating Kerr Black Hole Immersed in Magnetic Field

The dynamics of a charged particle moving around a slowly rotating Kerr black hole in the presence of an external magnetic field is investigated. We are interested to explore the conditions under which the charged particle can escape from the gravitational field of the black hole after colliding with another particle. The escape velocity of the charged particle in the innermost stable circular orbit is calculated. The effective potential and escape velocity of the charged particle with angular momentum in the presence of magnetic field is analyzed. This work serves as an extension of a preceding paper dealing with the Schwarzschild black hole [Zahrani {\it et al}, Phys. Rev. D 87, 084043 (2013)].Comment: 20 pages, 12 figure

Dynamics of Particles Around a Schwarzschild-like Black Hole in the Presence of Quintessence and Magnetic Field

We investigate the dynamics of a neutral and a charged particle around a static and spherically symmetric black hole in the presence of quintessence matter and external magnetic field. We explore the conditions under which the particle moving around the black hole could escape to infinity after colliding with another particle. The innermost stable circular orbit (ISCO) for the particles are studied in detail. Mainly the dependence of ISCO on dark energy and on the presence of external magnetic field in the vicinity of black hole is discussed. By using the Lyapunov exponent, we compare the stabilities of the orbits of the particles in the presence and absence of dark energy and magnetic field. The expressions for the center of mass energies of the colliding particles near the horizon of the black hole are derived. The effective force on the particles due to dark energy and magnetic field in the vicinity of black hole is also discussed.Comment: 25 pages, 17 figures, accepted for publication in the European Physical Journal

Strong Gravitational Lensing by Kiselev Black Hole

We investigate the gravitational lensing scenario due to Schwarzschild-like black hole surrounded by quintessence (Kiselev black hole). We work for the special case of Kiselev black hole where we take the state parameter $w_{q}=-\frac{2}{3}$. For the detailed derivation and analysis of the bending angle involved in the deflection of light, we discuss three special cases of Kiselev black hole: non-extreme, extreme and naked singularity. We also calculate the approximate bending angle and compare it with exact bending angle. We found the relation of bending angles in the decreasing order as: naked singularity, extreme Kiselev black hole, non-extreme Kiselev black hole and Schwarzschild black hole. In the weak field approximation, we compute the position and total magnification of relativistic images as well

Particle Dynamics Around Weakly Magnetized Reissner-Nordstr\"{o}m Black Hole

Considering the geometry of Reissner-Nordstr\"{o}m (RN) black hole immersed in magnetic field we have studied the dynamics of neutral and charged particles. A collision of particles in the inner stable circular orbit is considered and the conditions for the escape of colliding particles from the vicinity of black hole are given. The trajectories of the escaping particle are discussed. Also the velocity required for this escape is calculated. It is observed that there are more than one stable regions if magnetic field is present in the accretion disk of black hole so the stability of ISCO increases in the presence of magnetic field. Effect of magnetic field on the angular motion of neutral and charged particles is observed graphically.Comment: 16 pages, 16 figures, version accepted for publication in 'Advances in High Energy Physics

A Study of Casual Relationship of Job Design and Employee’s Behavior

Some factors other than higher salaries, compensation benefits and conducive workplace seem to have strong impact on employee’s performance i.e. organization citizenship behavior and counterproductive work behavior.  Purpose of this study is to examine the impact of job design elements i.e. job enlargement, job enrichment and job rotation on employee’s organizational citizenship behavior and counterproductive work behavior in the banking sector of Faisalabad and extent to which this relationship is mediated by motivation. Data was collected from 170 frontline managers of banks. After analysis of data, it was found that that there is a positive and significant relationship between job enlargements, job enrichment on OCB while negative and significant relationship between job rotation and OCB. Negative and significant relationship between job enlargement and CWB, negative but insignificant relationship between job enrichment and CWB while positive and significant relationship was found between the job rotation and CWB. Motivation was partially mediating the relationship between job enlargement, enrichment, rotation and organizational citizenship behavior, while motivation was partially mediating the relationship between job rotation and counterproductive work behavior. This study enhances the existing literature of job design and contributes to research by finding how job design influences the OCB & CWB.&nbsp

Serological and Molecular Investigation of Brucella Species in Dogs in Pakistan

Brucellosis is an important bacterial zoonosis caused by B. abortus and B. melitensis in Pakistan. The status of canine brucellosis caused by B. canis remains obscure. In total, 181 serum samples were collected from stray and working dogs in two different prefectures viz. Faisalabad (n = 87) and Bahawalpur (n = 94). Presence of antibodies against B. canis and B. abortus/B. melitensis was determined using the slow agglutination test (SAT) and ELISA, respectively. Real-time PCR was performed to detect and differentiate Brucella DNA at the species level. In Faisalabad, the serological prevalence was found to be 9.2% (8/87) and 10.3% (9/87) by SAT and ELISA, respectively. Only one of the ELISA positive samples (1.15%) yielded amplification for B. abortus DNA. In Bahawalpur, 63.8% (60/94) samples were found positive by SAT; however, none of the samples was positive by ELISA or by real-time PCR. Location, age (≥1 year) and body condition (weak) were found to be associated with B. canis infection, whereas presence of wounds was found to be associated with B. abortus infection only. These findings point towards a risk of transmission from dog to livestock and humans and vice versa. The study expects to draw the attention of concerned authorities towards infection prevention and animal welfare. This study warrants further epidemiological investigation on brucellosis in pet dogs and their owners. To the best of our knowledge, this is first ever report on B. canis and B. abortus in dogs in Pakistan

Assessment of Wastewater Quality of Paharang Drain and its Impact on the Ground Water Quality of Adjacent Areas

This study was conducted to assess the effect of wastewater quality of Paharang drain Faisalabad on ground water quality of adjacent areas. Ground water samples and drain water samples were collected and analyzed by using standard methods. Parameters of wastewater samples were compared with Pakistan National Environmental Quality Standards (NEQS). Results indicated that physico-chemical parameters including pH, total dissolved solids (TDS), chloride, fluoride and total hardness were found exceeding the permissible limits in wastewater samples. Similarly, few physicochemical parameters in groundwater were found within the permissible limit while electrical conductivity (EC), TDS, chlorides (Cl), fluoride (F), and total hardness in most of samples were found above the Pak EPA and WHO standard limits. Heavy metals like nickel (Ni), chromium (Cr), iron (Fe), lead (Pb), and arsenic (As) were found within the prescribed concentrations in drain and ground water samples. Statistical analysis showed significant effect of some drain wastewater parameters like conductivity, TDS, salt, temperature, and Cl on the corresponding ground water quality. A strong positive correlation between pH, EC, TDS, Salt, and Cl in drain wastewater and strong positive correlation between EC, TDS and Salt in ground water samples was observed. For improving the ground water quality in the adjacent areas textile wastewater treatment all factories is required, and a combined effluent treatment plant (CETP) at the Paharang drain is also recommended

Particle Dynamics around Weakly Magnetized Reissner-Nordström Black Hole

The publication of this article was funded by SCOAP 3 . Considering the geometry of Reissner-Nordström (RN) black hole immersed in magnetic field, we have studied the dynamics of neutral and charged particles. A collision of particles in the inner stable circular orbit is considered and the conditions for the escape of colliding particles from the vicinity of black hole are given. The trajectories of the escaping particle are discussed. Also, the velocity required for this escape is calculated. It is observed that there is more than one stable region if magnetic field is present in the accretion disk of black hole, so the stability of ISCO increases in the presence of magnetic field. Effect of magnetic field on the angular motion of neutral and charged particles is observed graphically