Cosmic acceleration in a model of scalar-tensor gravitation

In this paper we consider a model of scalar-tensor theory of gravitation in which the scalar field, $\phi$ determines the gravitational coupling G and has a Lagrangian of the form, $\mathcal{L}_{\phi} =-V(\phi)\sqrt{1 - \partial_{\mu}\phi\partial^{\mu}\phi}$. We study the cosmological consequence of this theory in the matter dominated era and show that this leads to a transition from an initial decelerated expansion to an accelerated expansion phase at the present epoch. Using observational constraints, we see that the effective equation of state today for the scalar field turns out to be $p_{\phi}=w_{\phi}{\rho}_{\phi}$, with $w_{\phi}=-0.88$ and that the transition to an accelerated phase happened at a redshift of about 0.3.Comment: 12 pages, 2 figures, matches published versio

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A note on perfect scalar fields

We derive a condition on the Lagrangian density describing a generic, single, non-canonical scalar field, by demanding that the intrinsic, non-adiabatic pressure perturbation associated with the scalar field vanishes identically. Based on the analogy with perfect fluids, we refer to such fields as perfect scalar fields. It is common knowledge that models that depend only on the kinetic energy of the scalar field (often referred to as pure kinetic models) possess no non-adiabatic pressure perturbation. While we are able to construct models that seemingly depend on the scalar field and also do not contain any non-adiabatic pressure perturbation, we find that all such models that we construct allow a redefinition of the field under which they reduce to pure kinetic models. We show that, if a perfect scalar field drives inflation, then, in such situations, the first slow roll parameter will always be a monotonically decreasing function of time. We point out that this behavior implies that these scalar fields can not lead to features in the inflationary, scalar perturbation spectrum.Comment: v1: 11 pages; v2: 11 pages, minor changes, journal versio

Studies on arsenical creosote as a wood preservative for marine structures. Part 2. Observation on leaching, corrosion and resistance to borer attack

A detailed study on arsenical creosote with reference to leaching, corrosion and anti-borer properties was carried out. Results showed that aging had very little effect on the preservative which suggested better fixation of the preservative into the wood. Corrosion of mild steel, galvanised iron, aluminium-magnesium alloy (M57S) and copper panels in the preservative was found to be negligible. Normal creosote and low temperature creosote of Regional Research Laboratory, Hyderabad, both fortified with arsenic trioxide resisted borer damage on wooden panels for a period of over five months in the port of Cochin. The performance of low temperature creosote fortified with arsenic was found to be equally satisfactory when compared to normal creosote fortified in the same manner. A loading of 208.6 Kgs/ml³ for Haldu (Adina cordifolia) and 138 Kgs/m³ for Mango (Mangifera indica) in the case of normal creosote and 177 Kgs/m³ for Mango the case of RRL creosote were found to be sufficient for treating the wood

Sonoluminescence as Quantum Vaccum Radiation

We argue that the available experimental data is not compatible with models of sonoluminescence which invoke dynamical properties of the interface without regard to the compositional properties of the trapped gas inside the bubble.Comment: 2 pages,Revtex,No figures,Submitted to PRL(comments

Unexpected and Abnormally Low Hdl Cholesterol Levels on Combination Hypolipidemic Therapy

Abstract In general, Indians have low HDL cholesterol levels. Fenofibrate, a drug widely used in the treatment of hypertriglyceridemia, usually also increases HDL cholesterol. There have been a few reports in the literature of a paradoxical decrease in serum HDL-cholesterol in patients treated with fenofibrate, either alone or in combination with a statin. We report three cases of paradoxical decrease in serum HDL- cholesterol in type 2 diabetic patients treated with a statin-fenofibrate combination

Effect of Nannochloropsis salina on the survival and growth of phyllosoma of the tropical spiny lobster, Panulirus homarus L. under laboratory conditions

The first successful advanced (stage VIII) larval development of the tropical spiny lobster, Panulirus homarus L. under laboratory culture has been achieved in a short span of 42 days. The culture treatments were maintained in two different systems, one with microalgae, Nannochloropsis salina (30-40 million cells/mL) and the other without microalgae. Phyllosoma attained stage VIII (5.25 mm) and stage V (3.36 mm) with an intermoult period of 4-6 and 5-9 days in the two systems respectively. The larvae moulted nine and six times in the microalgal and non-algal systems, respectively. Phyllosoma were fed with freshly hatched live Artemia salina nauplii (0.32 mm) for an initial period of 10 days, followed by juvenile Artemia (1.45 –1.54 mm) enriched with microalgae for the subsequent 15 days. Artemia enriched with commercial polyunsaturated fatty acid concentrate (DHA-Selco) was fed to the larvae for the rest of the culture period. Salinity and temperature were maintained at 33 ± 2 ppt and 28 ± 2 0C, respectively, while the pH recorded an optimum of 7.9 ± 0.5. The microalgal larval rearing system had lower bacterial load (total heterotrophic marine count, 1.0 X 103 CFU m L-1 and total Vibrio sp. count, 20 CFU/mL) compared to the nonmicroalgal system

On the importance of ship-bottom fouling by marine organisms: a techno-economic survey

A high attention has been paid for constant research on the preservation of materials in the marine environment. This includes all phases of design, development, applied engineering and economics which may influence the construction and operation of ships and underwater installations