Absorption cross section of RN and SdS extremal black hole

The nature of scalar wave functions near the horizon of Reissner Nordstrom (RN) extremal and Schwarzschild-de Sitter (SdS) extremal black holes are found using WKB approximation and the effect of reflection of waves from the horizon. The absorption cross section $\sigma_{abs}$ when RN extremal and SdS extremal black holes placed in a Klein-Gordon field is calculated.Comment: 11 pages, Preprint to IJMP

Yang-Mills theory for bundle gerbes

Given a bundle gerbe with connection on an oriented Riemannian manifold of dimension at least equal to 3, we formulate and study the associated Yang-Mills equations. When the Riemannian manifold is compact and oriented, we prove the existence of instanton solutions to the equations and also determine the moduli space of instantons, thus giving a complete analysis in this case. We also discuss duality in this context.Comment: Latex2e, 7 pages, some typos corrected, to appear in J. Phys. A: Math. and Ge

Plankton Productivity in Lagoons of Agatti and Bangaram Atolls of Lakshadweep Archipelago, India

Phytoplankters and zooplankters function as important links in the food chain and form the food of a large number of organisms in the aquatic ecosystem. As plankters play an important role in the health of an aquatic ecosystem, the study on these resources in the productive aquatic ecosystems of Lakshadweep is significant. Earlier studies carried out earlier from Agatti and Bangaram are by Pratap et al. (1977), Achuthankutty et al. (1989) and Casanova & Nair (1999). No recent reports are available on plankters from Agatti and Bangaram. Hence, an attempt is made to study the qualitative and quantitative abundance of phytoplankters and zooplankters in the selected lagoons of Lakshadweep

Fish/prawn seed resources and hydrography in the surf and backwater at Cochin

The present study deals with the seasonal variations of hydrographic parameters and fish and prawn seed and juvenile resources in the intertidal surf zone of the sea and the ajoining backwater at Cochin based on regular monitoring of monthly data for 1996-2001

Phase transitions of a single polyelectrolyte in a poor solvent with explicit counterions

Conformational properties of a single flexible polyelectrolyte chain in a poor solvent are studied using constant temperature molecular dynamics simulation. The effects of counterions are explicitly taken in to account. Structural properties of various phases and the transition between these phases are studied by tracking the values of asphericity, radius of gyration, fraction of condensed counterions, number of non-bonded neighbours and Coulomb interaction energies. From our simulations, we find strong evidence for a first-order phase transition from extended to collapsed phase consistent with earlier theoretical predictions. We also identify a continuous phase transition associated with the condensation of counterions and estimate the critical exponents associated with the transition. Finally, we argue that previous suggestions of existence of an independent intermediate phase between extended and collapsed phases is only a finite size effect.Comment: 7 pages, 8 figure

Pivotal role of families in doctor–patient communication in oncology: a qualitative study of patients, their relatives and cancer clinicians

Families are a unique source of support for many cancer patients. Most advanced communication skills training for oncologists are patient centred and do not cover interactions with family members. The current study used in-depth qualitative interviews of patients, relatives and cancer clinicians with thematic analysis to explore the role of family members in the communication process. Forty-one participants included 10 cancer patients, 10 relatives ensuring proportionate representation of both gender and primary cancer site and 21 doctors representing both medical and surgical oncology. Nineteen of 20 patients and relatives wanted an "open and honest" discussion with their doctors. All patients, relatives and doctors preferred involvement of the family at most stages of cancer treatment. Five themes were identified in relation to communication with family members. The participants highlighted the "importance of family for physical and psychological care," they emphasised the need to "balance patient autonomy and relatives desire to be protective" using varied "negotiating strategies" that are influenced by "socioeconomic circumstances of both patient and family." The doctor-patient-relative communication process was not static with preferences changing over time. The data suggests that communication skills training of cancer clinicians should incorporate modules on better communication with relatives

Characterization of a 50kW Inductively Coupled Plasma Torch for Testing of Ablative Thermal Protection Materials

With the development of new manned spaceflight capabilities including NASA's Orion capsule and the Space-X Dragon capsule, there is a renewed importance of understanding the dynamics of ablative thermal protection systems. To this end, a new inductively coupled plasma torch facility is being developed at UT-Austin. The torch operates on argon and/or air at plasma powers up to 50 kW. In the present configuration the flow issues from a low-speed subsonic nozzle and the hot plume is characterized using slug calorimetry and emission spectroscopy. Preliminary measurements using emission spectroscopy have indicated that the torch is capable of producing an air plasma with a temperature between 6,000 K and 8,000 K depending on the power and flow settings and an argon plasma with a temperature of approximately 12,000 K. The operation envelope was measured, and heat flux measured for every point within the envelope using both a slug calorimeter and a Gardon gauge heat flux sensor. The torch was found to induce a stagnation point heat flux of between 90 and 225 W/sq cm

Studies on Composite Extrudable Propellant with varied Burning Rate Pressure Index 'n'

This paper discusses the development of composite propellantextrusion technique and the study of burning rate pressure indices nwith respect to compositional variations. The n is found to vary from0.35 to plateau and plateau to mesa by suitable compositionalmodifications. Compositional influence on burning rate with specificreference to plateau and mesaburning additives is described. Detailsof the process parameters like fluidity of the slurry, extrusion pressure,extrusion rate and die-swell are presented. This propellant is based onISRO-CTPB binder using ISRO-AP as oxidizer. Ammonium perchlorate (AP) particle size variation and inclusion of additives likePVC, lead stearate, ammonium sulphate, lithium fluoride etc. are foundto influence the burning rate pressure index n