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

Active Vibration Control of Structures using an Impedance Matching Control Technique

Active vibration control of structures has gained a lot of interest in recent years. This paper presents an active vibration control methodology of a structure using piezoelectric actuators. The proposed methodology is useful in practical applications where the system to be controlled is difficult to model due to the presence of complex boundary conditions. The impedance matching control technique uses a power flow approach wherein the controller is designed such that the power flow into the structure is minimized. The system transfer function is obtained from the experimental collocated actuator/sensor pair data using Eigen Realisation Algorithm (ERA). The controller is designed for the system transfer function according to impedance matching theory. The above approach is targeted towards the vibration control of wind tunnel stings, which suffer from flow-induced vibration. A wind tunnel sting model is designed and fabricated for this study. The real time implementation of the impedance matching controller has been carried out using dSPACE® Digital Signal Processor (DSP) card. The results are encouraging and demonstrate the feasibility of applying this technique in the wind tunne

Anion mediated polytype selectivity among the basic salts of Co(II)

Basic salts of Co(II) crystallize in the rhombohedral structure. Two different polytypes, 3R1 and 3R2, with distinct stacking sequences of the metal hydroxide slabs, are possible within the rhombohedral structure. These polytypes are generated by simple translation of successive layers by (2/3, 1/3, z) or (1/3, 2/3, z). The symmetry of the anion and the mode of coordination influences polytype selection. Cobalt hydroxynitrate crystallizes in the structure of the 3R2 polytype while the hydroxytartarate, hydroxychloride and α-cobalt hydroxide crystallize in the structure of the 3R1 polytype. Cobalt hydroxysulfate is turbostratically disordered. The turbostratic disorder is a direct consequence of the mismatch between the crystallographically defined interlayer sites generated within the crystal and the tetrahedral symmetry of the SO4 2- ions. © 2006 Elsevier Inc. All rights reserved

Imaging the dust sublimation front of a circumbinary disk

We present the first near-IR milli-arcsecond-scale image of a post-AGB binary that is surrounded by hot circumbinary dust. A very rich interferometric data set in six spectral channels was acquired of IRAS08544-4431 with the new RAPID camera on the PIONIER beam combiner at the Very Large Telescope Interferometer (VLTI). A broadband image in the \textit{H} band was reconstructed by combining the data of all spectral channels using the SPARCO method. We spatially separate all the building blocks of the IRAS08544-4431 system in our milliarcsecond-resolution image. Our dissection reveals a dust sublimation front that is strikingly similar to that expected in early-stage protoplanetary disks, as well as an unexpected flux signal of $\sim$4\% from the secondary star. The energy output from this companion indicates the presence of a compact circum-companion accretion disk, which is likely the origin of the fast outflow detected in H$\alpha$. Our image provides the most detailed view into the heart of a dusty circumstellar disk to date. Our results demonstrate that binary evolution processes and circumstellar disk evolution can be studied in detail in space and over time.Comment: PR @ http://www.eso.org/public/news/eso1608

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

A study of prescription pattern in the drug therapy of ear, nose, and throat infections at a tertiary care hospital in Mangalore

Background: Diseases of the ear, nose, and throat (ENT) constitute among the most common causes of hospital visits worldwide and account for most of the antibiotics prescribed and used. They are responsible for significant school and work absenteeism and have generated 94.6 disability-adjusted life years lost worldwide. Due to the high incidence of these diseases and the different varieties of drugs in use, it becomes imperative for us to know the present prescribing patterns, so that appropriate adjustments can be made for the benefit of patients.Methods: Over a period of 1-year, the outpatient department (OPD) records of 608 patients with ENT infections, reporting to the ENT OPD of Justice K S Hegde Charitable Hospital, Deralakatte, Mangalore, were scrutinized and the data collected in a specially designed proforma. Descriptive analysis of the data was done.Results: Of the total 608 prescriptions analyzed, 309 (50.8%) belonged to male patients and 299 (49.2%) belonged to female patients. Highest numbers of patients were in the age group of 16-25 years (29.44%). The most common diseases reported were chronic suppurative otitis media (19.24%), followed by otitis externa (13.49%) and furunculosis (9.87%). Average number of drugs per prescription was found to be 3.0. Oral antibiotics were prescribed to 540 patients (88.81%). Most common antibiotics prescribed were amoxicillin-clavulanate (53%), levofloxacin (17%), and cefixime (14%). Antihistamines were prescribed in 52.47% prescriptions, and non-steroidal anti-inflammatory drugs were prescribed to 298 patients (49.01%).Conclusion: This study shows that the diseases were treated rationally in accordance with the standard guidelines of therapy

Survey on Early Detection of Alzheimer's Disease using Different Types of Neural Network Architecture

Alzheimer’s disease is a condition that leads to, progressive neurological brain disorder and destroys cells of the brain thereby causing an individual to lose their ability to continue daily activities and also hampers their mentality. Diagnostic symptoms are experienced by patients usually at later stages after irreversible neural damage occurs. Detection of AD is challenging because sometimes the signs that distinguish AD MRI data, can be found in MRI data of normal healthy brains of older people. Even though this disease is not completely curable, earlier detection can aid in promising treatment and prevent permanent damage to brain tissues. Age and genetics are the greatest risk factors for this disease. This paper presents the latest reports on AD detection based on different types of Neural Network Architectures