Scalar filed evolution and area spectrum for Lovelock-AdS black holes

We study the modes of evolution of massless scalar fields in the asymptotically AdS spacetime surrounding maximally symmetric black holes of large and intermediate size in the Lovelock model. It is observed that all modes are purely damped at higher orders. Also, the rate of damping is seen to be independent of order at higher dimensions. The asymptotic form of these frequencies for the case of large black holes is found analytically. Finally, the area spectrum for such black holes is found from these asymptotic modes.Comment: 15 pages, 6 figures, published online in Gen. Relativ. Gravi

Quasinormal Modes of Lovelock Black Holes

The quasinormal modes of metric perturbations in asymptotically flat black hole spacetimes in the Lovelock model are calculated for different spacetime dimensions and higher orders of curvature. It is analytically established that in the asymptotic limit $l \rightarrow \infty$, the imaginary parts of the quasi normal frequencies become constant for tensor, scalar as well as vector perturbations. Numerical calculation shows that this indeed is the case. Also, the real and imaginary parts of the quasinormal modes are seen to increase as the order of the theory $k$ increases. The real part of the modes decreases as the spacetime dimension $d$ increases, indicating the presence of lower frequency modes in higher dimensions. Also, it is seen that the modes are roughly isospectral at very high values of the spacetime dimension $d$

Study of young stellar objects and associated filamentary structures in the inner Galaxy

Young Stellar Objects (YSOs) in the inner Galactic region $10^0 < l < 15^0$ and $-1^0 < b < 1^0$ are studied using GLIMPSE images and GLIMPSE data catalogue. A total number of 1107 Class I and 1566 Class II sources are identified in this Galactic region. With the help of GLIMPSE 5.8 $\mu$m & 8 $\mu$m images, we have identified the presence of 10 major star forming sites in the Galactic midplane, of which 8 of them are filamentary while 2 are possible clusters of Class I & II sources. The length of the identified filaments are estimated as 8'-33' ($\sim$ 9 - 56 pc). Occurrence of Hub-Filamentary System (HFS) is observed in many filamentary star forming sites. Most of the Class I sources are found to be aligned along the length of these filamentary structures, while Class II sources have a random distribution. Mass and age distribution of 425 Class I and 241 Class II sources associated with filaments & clusters are studied through their SED analysis. Most of the Class I sources detected have mass $>$ 8M$_\odot$, while Class II sources have relatively low mass regime. Class I sources have ages $\le$ 0.5 Myr, while Class II sources have ages in the range $\sim$0.1 - 3 Myr. Along with the help of high mass star forming tracers, we demonstrate that the 10 regions studied here are forming a large number of high-mass stars.Comment: 19 pages, 18 figures. Accepted for publication in MNRA

A cost effective school management system for disadvantaged schools in the Free State province using the software as a service (SaaS) delivery model

Thesis (M. Tech. (Information Technology)) -- Central University of technology, Free State, 2013The aim of this study was to create a dynamic software system that captures all information related to a student and delivers it to the educators, principal, higher authorities and parents. In order to achieve this aim, an investigation was launched as to the development of a cost-effective school management system for disadvantaged schools in the Free State Province using the Software as a Service (SaaS) delivery model. Although a variety of other school management systems exist in the market, they are often expensive and difficult to maintain. Details such as previous academic performances, disciplinary actions taken against a student in the current school, ailments the student suffers from and parental details are some of the information that will help an educator to better understand a student. The software that is currently in use fails to deliver this information. Designing the software as a multitenant system, helps accommodate different schools under the same database, while the shared database, shared schema reduces back-end costs. Database design was carried out in such a way that tenant data is logically isolated and that data integrity is maintained throughout. What makes the software explained in this study cost effective is the method of delivery that was employed, which is SaaS. Here, software is not purchased, there is no upfront capital and the yearly license fee is eliminated, as schools need only pay a monthly rental fee for the services they use. Since all services are provided through the Internet, there is no need for system space; the only requirement is a high-speed Internet network

Functional stability of HIV-1 envelope trimer affects accessibility to broadly neutralizing antibodies at its apex

ABSTRACT The trimeric envelope glycoprotein spike (Env) of HIV-1 is the target of vaccine development to elicit broadly neutralizing antibodies (bnAbs). Env trimer instability and heterogeneity in principle make subunit interfaces inconsistent targets for the immune response. Here, we investigate how functional stability of Env relates to neutralization sensitivity to V2 bnAbs and V3 crown antibodies that engage subunit interfaces upon binding to unliganded Env. Env heterogeneity was inferred when antibodies neutralized a mutant Env with a plateau of less than 100% neutralization. A statistically significant correlation was found between the stability of mutant Envs and the MPN of V2 bnAb, PG9, as well as an inverse correlation between stability of Env and neutralization by V3 crown antibody, 447-52D. A number of Env-stabilizing mutations and V2 bnAb-enhancing mutations were identified in Env, but they did not always overlap, indicating distinct requirements of functional stabilization versus antibody recognition. Blocking complex glycosylation of Env affected V2 bnAb recognition, as previously described, but also notably increased functional stability of Env. This study shows how instability and heterogeneity affect antibody sensitivity of HIV-1 Env, which is relevant to vaccine design involving its dynamic apex. IMPORTANCE The Env trimer is the only viral protein on the surface of HIV-1 and is the target of neutralizing antibodies that reduce viral infectivity. Quaternary epitopes at the apex of the spike are recognized by some of the most potent and broadly neutralizing antibodies to date. Being that their glycan-protein hybrid epitopes are at subunit interfaces, the resulting heterogeneity can lead to partial neutralization. Here, we screened for mutations in Env that allowed for complete neutralization by the bnAbs. We found that when mutations outside V2 increased V2 bnAb recognition, they often also increased Env stability-of-function and decreased binding by narrowly neutralizing antibodies to the V3 crown. Three mutations together increased neutralization by V2 bnAb and eliminated binding by V3 crown antibodies. These results may aid the design of immunogens that elicit antibodies to the trimer apex. </jats:p

Evolution of electromagnetic and Dirac perturbations around a black hole in Horava gravity

The evolution of electromagnetic and Dirac perturbations in the spacetime geometry of Kehagias-Sfetsos(KS) black hole in the deformed Horava-Lifshitz(HL) gravity is investigated and the associated quasinormal modes are evaluated using time domain integration and WKB methods. We find a considerable deviation in the nature of field evolution in HL theory from that in the Schwarzschild spacetime and QNMs region extends over a longer time in HL theory before the power-law tail decay begins. The dependence of the field evolution on the HL parameter $\alpha$ are studied. In the time domain picture we find that the length of QNM region increases with $\alpha$. But the late time decay of field follows the same power-law tail behavior as in the case of Schwarzschild black hole.Comment: The article was fully rewritten, references added, to appear in MPL

Marine fisheries of the south-west coast of India during 2009-2010

The south-west coast of India has been the major contributor of the country’s fish production with a coastline of 994 km along the maritime states of Kerala, Karnataka and Goa. In this region, 2.79 lakh fishermen are directly or indirectly involved in marine fisheries sector. The marine fish landings in this coast continued to grow, rising from 8.75 lakh t to 10.83 lakh t, contributing 27.3% and 32.4% to the national fish production in 2009 and 2010 respectively

Marine fisheries of the north-east coast of India during 2009-2010

The states of Odisha and West Bengal constituting the north-east coast of India has a coastline of 638 km. The coastal area is cycloneprone and is worst affected during the south-west monsoon. The total number of marine fish landing centres in north-east coast is 132, of which 73 belonged to Odisha. According to Marine Fisheries Census 2010, there are 3.95 lakh fisherfolk directly engaged in actual fishing, fish seed collection and fishing allied activities in this coast