213 research outputs found
Unflattened photon beams from the standard flattening filter free accelerators for radiotherapy: Advantages, limitations and challenges
No full textNew analytical stellar models in general relativity.
Get PDFThesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2009.We present new exact solutions to the Einstein and Einstein-Maxwell field equations that model the interior of neutral, charged and radiating stars. Several new classes of solutions in static spherically symmetric interior spacetimes are found in the presence of charge. These correspond to isotropic matter with a specified electric field intensity. Our solutions are found by choosing different rational forms for one of the gravitational potentials and a particular form for the electric field. The models generated contain results found previously including Finch and Skea (1989) neutron stars, Durgapal and Bannerji (1983) dense stars, Tikekar (1990) superdense stars in the limit of vanishing charge. Then we study the general situation of a compact relativistic object with anisotropic pressures in the presence of the electromagnetic field. We assume the equation of state is linear so that the model may be applied to strange stars with quark matter and dark energy stars. Several new classes of exact solutions are found, and we show that the densities and masses are consistent with real stars. We regain as special cases the Lobo (2006) dark energy stars, the Sharma and Maharaj (2007) strange stars and the realistic isothermal universes of Saslaw et al (1996). In addition, we consider relativistic radiating stars undergoing gravitational collapse when the fluid particles are in geodesic motion. We transform the governing equation into Bernoulli, Riccati and confluent hypergeometric equations. These admit an infinite family of solutions in terms of simple elementary functions and special functions. Particular models contain the Minkowski spacetime and the Friedmann dust spacetime as limiting cases. Finally, we model the radiating star with shear, acceleration and expansion in the presence of anisotropic pressures. We obtain several classes of new solutions in terms of arbitrary functions in temporal and radial coordinates by rewriting the junction condition in the form of a Riccati equation. A brief physical analysis indicates that these models are physically reasonable
"A Comparative Analysis of Cost Effectiveness on Productivity" - (With Special Reference to Saurashtra University and Gujarat University)
No full textNot availabl
Radiation dose to patients from X-ray radiographic examinations using computed radiography imaging system
No full textThe screen-film system is replaced by computed radiography system for recording the images of the patients during X-ray radiography examinations. The change in imaging system requires the re-establishment of the institutional diagnostic reference levels (DRLs) for different types of X-ray examinations conducted at the hospital. For this purpose, patient specific parameters [age, height, weight, body mass index (BMI), object to image distance (OID)] and machine specific parameters (kVp, mAs, distance and field sizes) of 1875 patients during 21 different types of X-ray examinations were recorded for estimating the entrance skin dose (ESD). The ESD for each of these patients were estimated using measured X-ray beam output and the standard value of the back scatter factor. Five number summary was calculated for all the data for their presentation in the Box-Whisker plot, which provides the statistical distribution of the data. The data collected indicates that majorly performed examinations are cervical spine AP, Chest PA and Knee Lat with percentage contributions of 16.05, 16 and 8.27% respectively. The lowest contribution comes from Hip Lat which is about 1.01%. The ratio of measured ESD (maximum to minimum) for these examinations is found to be highest for the cervical spine AP with a value of 50 followed by Thoracic spine AP of 32.36. The ESD ratio for Chest PA, Knee Lat and Lumbar Spine AP are 30.75, 30.4 and 30.2 respectively. The lowest ESD ratio is for Hip Lat which is 2.68. The third quartile values of ESDs are established as the institutional DRLs. The ESD values obtained for 21 different X-ray projections are either comparable or lesser than the reported national/international values
Political dimension of Indian federal system: an evaluation
Get PDFIndian federalism is a blend of formation of federations of both the existing modes of federations The prevailing situations at the juncture in the country forced the Constituent Assembly to make India a federation with the strong central government. The constitution makes adequate provisions for a true federation to meet out all the exigencies. In practice, it reflects both federal and unitary governments’ features as per the demand of the situations and has experienced, the bitter taste of emergency and coalition government. The decisions of the Hon’ble Supreme Court also contributed to clearing the grey areas. Undoubtedly, the constitution is a fundamental document to provide the guidelines and limits to government. Its success and applicability ultimately depend upon the mental make-up, honesty, and commitment of the persons at the helm of the affairs. The present write-up comprises of salient features of Indian federation, its historical profile, and the concluding remarks
Mineral Status of Livestock, Soil, Feeds and Fodders in Ajmer District of Rajasthan
Get PDFA large number of Indian livestock suffer from deficiencies or imbalances in minerals because they are mainly maintained on crop residue based rations and grazing without access to mineral supplement (Mc Dowell et al., 1993). Deficiency or imbalance of single or multiple minerals results in enzymatic dysfunction and hormonal imbalance associated with fertility of animals (Maurice, 2003). In India where dietary concentration of fodder fed to the animals are unknown or highly variable due to availability, season, location, forage, species and animal potential (Sharma et al., 2003), it is important to determine plasma mineral concentrations in animal region wise, to estimate needs of livestock so as to obtain optimum productivity and to access the effect of mineral deficiencies on serum vitamins, hormone and enzyme profile. Limited information is available on the feeding practices and mineral status of livestock, soil and feed in Kekri block of Ajmer district. Keeping this in view the present study was conducted in Kekri block of Ajmer district to establish relationship for different minerals among livestock, soil and feed in order to suggest dietary supplementation of area specific mineral mixture
- …
