Near-Infrared and Optical Studies of the fast nova V4643 Sgr (Nova Sagittarii 2001)

V4643 Sagittarii or Nova Sagittarii 2001 was discovered in outburst at 7.7 mag. on 2001 February 24. Here, we present near-infrared results of this fast classical nova obtained in the early decline phase in 2001 March followed by optical observations about one month later. Subsequently we also present near-infrared spectra taken later in the nova's evolution, about four months after the outburst, when V4643 Sgr had entered the coronal phase. The spectra in the early decline phase are dominated by emission lines of the HI Brackett series and also the Paschen beta and gamma lines. We study the cause of the excitation of the the OI line at 1.128 micron and discuss the variation in its strength with time after outburst. We discuss the role of optical depth effects on the observed strengths of the hydrogen Brackett and Paschen lines and discuss possible reasons for the puzzling behavior of the Br gamma line strength and whether it is correlated with the OI 1.128 micron line behavior. An optical spectrum is presented which shows that HeII lines are the most prominent features - after HI - to be seen in early 2001 April. We present and also discuss spectra taken in 2001 June and August which prominently show coronal lines of [Si VI] and [Si VII] at 1.9641 micron and 2.4807 micron respectively.Comment: Accepted in MNRA

The energy-momentum tensor,the trace identity and the Casimir effect

The trace identity associated with the scale transformation x^\mu\tox'{}^\mu = e^{-\rho}x^\mu on the Lagrangian density for the noninteracting electromagnetic field in the covariant gauge is shown to be violated on a single plate on which the Dirichlet boundary condition $A^\mu(t,x^1,x^2,x^3=-a) = 0$ is imposed.It is however respected in free space,i.e. in the absence of the plate; these results reinforce our assertions in an earlier paper where the same exercise was carried out using the Lagrangian density for the free,massive,real scalar field in 2 + 1 dimensions.Comment: 22 page

An Ayurvedic approach to Non Infectious Choroiditis - Prospective Single Case Study

Background: Many diseases arise when the body’s immune system attacks the host’s own tissue. Non infectious Choroiditis is one such disease that involves the posterior part of eye, hence it is also called as posterior uveitis. It refers to inflammation of the choroid, the back part of uvea. Uveitis is an important cause of vision loss worldwide due to its sight threatening complications. This condition affects males and females in equal numbers. It can strike at almost any age, although it appears most often to occur between the ages of 20 and 50. According to one estimate, chronic, non-infectious posterior uveitis affects 800,000 people worldwide. Aim: Adopt Ayurvedic treatment principles to resolve the ailment and to overcome the recurrence. Methodology: 36 years female housewife approached Shalakya Tantra OPD, GAMC, Bengaluru with chief complaints of diminished vision in right eye with flashes and floaters since 2 years. Associated with mild pricking pain, redness of right eye occasionally, also photophobia and multiple joint pain. Results: Marked improvement has been noticed in the patient. Conclusion: Ayurvedic modality of treatment was found effective in treatment of uvetis by planning proper treatment after systematic analysis of disease pathology, cause and clinical features and treatment based on Dosha and Samprapti of disease stage. Adoption of standard protocols also helps significantly for the upliftment of Ayurveda

Nova V4444 Sagittarii 1999 in the early decline and quiescent phases

We present near-infrared and optical spectra of the fast nova V4444 Sagittarii at two single epochs in the early decline phase and unfiltered images obtained in quiescence. Based on this and other available data, we discuss about the nature of this nova, including the possibility of it being a recurrent nova

Water retention and shrinkage curves of weathered pyroclastic soil

The modelling of the triggering mechanism of rainfall-induced landslides in slopes covered by pyroclastic soil (as the area surrounding Mount Vesuvius in Campania, Italy) requires the hydraulic characterization of soil in unsaturated conditions in order to analyse the slope response to rainfalls. In previous studies carried out on Campanian pyroclastic soils, the volumetric soil changes due to suction changes have been disregarded, being them negligible in soils characterized by low plasticity and low clay contents. However, a more accurate determination of the water retention curve (WRC) in terms of volumetric water content requires a correct estimation of the total soil volume, which is affected by the soil stress-state. The proper approach would require the estimation of both WRC in terms of gravimetric water content and the shrinkage curve (SC). In the present study, a relation between void ratio and suction was determined for a pyroclastic soil sampled at Mount Faito in Southern Italy. Therefore, a correction of the volumetric water content was carried out resulting in updated water retention curves. Here, the matric suction was the only factor affecting the stress-state of the soil

Explicit MBR All-Symbol Locality Codes

Node failures are inevitable in distributed storage systems (DSS). To enable efficient repair when faced with such failures, two main techniques are known: Regenerating codes, i.e., codes that minimize the total repair bandwidth; and codes with locality, which minimize the number of nodes participating in the repair process. This paper focuses on regenerating codes with locality, using pre-coding based on Gabidulin codes, and presents constructions that utilize minimum bandwidth regenerating (MBR) local codes. The constructions achieve maximum resilience (i.e., optimal minimum distance) and have maximum capacity (i.e., maximum rate). Finally, the same pre-coding mechanism can be combined with a subclass of fractional-repetition codes to enable maximum resilience and repair-by-transfer simultaneously