Chemical abundance study of two strongly s-process enriched post-AGB stars in the LMC: J051213.81-693537.1 and J051848.86-700246.9

Context: This paper is part of a larger project in which we study the chemical abundances of extra-galactic post-AGB stars with the ultimate goal of improving our knowledge of the poorly understood AGB third dredge-up mixing processes and s-process nucleosynthesis. Aims: In this paper, we study two carefully selected post-AGB stars in the LMC. The combination of favourable atmospheric parameters for detailed abundance studies and their known distances make these objects ideal probes of the internal AGB third dredge-up and s-process nucleosynthesis in that they provide observational constraints for theoretical AGB models. Methods: We use high-resolution optical UVES spectra to determine accurate stellar parameters and perform detailed elemental abundance studies. Additionally, we use available photometric data to construct SEDs for reddening and luminosity determinations. We then estimate initial masses from theoretical post-AGB tracks. Results: Both stars show extreme s-process enrichment associated with relatively low C/O ratios of about 1.3. We could only derive upper limits of the lead (Pb) abundance which indicate no strong Pb overabundances with respect to other s-elements. Comparison with theoretical post-AGB evolutionary tracks in the HR-diagram reveals that both stars have low initial masses between 1.0 and 1.5 Msun. Conclusion: This study adds to the results obtained so far on a very limited number of s-process enriched post-AGB stars in the Magellanic Clouds. We find an increasing discrepancy between observed and predicted Pb abundances towards lower metallicities for all studied Magellanic Cloud post-AGB stars found so far, as well as moderate C/O ratios. We find that all s-process rich post-AGB stars in the LMC and SMC studied so far, cluster in the same region of the HR-diagram and are associated with low-mass stars with a low metallicity on average.Comment: 11 pages, 14 figure

Chemical abundance study of two strongly s-process enriched post-AGB stars in the LMC: J051213.81-693537.1 and J051848.86-700246.9

Context: This paper is part of a larger project in which we study the chemical abundances of extra-galactic post-AGB stars with the ultimate goal of improving our knowledge of the poorly understood AGB third dredge-up mixing processes and s-process nucleosynthesis. Aims: In this paper, we study two carefully selected post-AGB stars in the LMC. The combination of favourable atmospheric parameters for detailed abundance studies and their known distances make these objects ideal probes of the internal AGB third dredge-up and s-process nucleosynthesis in that they provide observational constraints for theoretical AGB models. Methods: We use high-resolution optical UVES spectra to determine accurate stellar parameters and perform detailed elemental abundance studies. Additionally, we use available photometric data to construct SEDs for reddening and luminosity determinations. We then estimate initial masses from theoretical post-AGB tracks. Results: Both stars show extreme s-process enrichment associated with relatively low C/O ratios of about 1.3. We could only derive upper limits of the lead (Pb) abundance which indicate no strong Pb overabundances with respect to other s-elements. Comparison with theoretical post-AGB evolutionary tracks in the HR-diagram reveals that both stars have low initial masses between 1.0 and 1.5 Msun. Conclusion: This study adds to the results obtained so far on a very limited number of s-process enriched post-AGB stars in the Magellanic Clouds. We find an increasing discrepancy between observed and predicted Pb abundances towards lower metallicities for all studied Magellanic Cloud post-AGB stars found so far, as well as moderate C/O ratios. We find that all s-process rich post-AGB stars in the LMC and SMC studied so far, cluster in the same region of the HR-diagram and are associated with low-mass stars with a low metallicity on average.Comment: 11 pages, 14 figure

Framework for reversible data hiding using cost-effective encoding system for video steganography

Importances of reversible data hiding practices are always higher in contrast to any conventional data hiding schemes owing to its capability to generate distortion free cover media. Review of existing approaches on reversible data hiding approaches shows variable scheme mainly focussing on the embedding mechanism; however, such schemes could be furthermore improved using encoding scheme for optimal embedding performance. Therefore, the proposed manuscript discusses about a cost-effective scheme where a novel encoding scheme has been used with larger block sizes which reduces the dependencies over larger number of blocks. Further a gradient-based image registration technique is applied to ensure higher quality of the reconstructed signal over the decoding end. The study outcome shows that proposed data hiding technique is proven better than existing data hiding scheme with good balance between security and restored signal quality upon extraction of data

DIRECTORY BASED CACHE COHERENCY, ORGANIZATION, OPERATIONS AND CHALLENGES IN IMPLEMENTATION - STUDY

Todays systems are designed with Multi Core Architecture. The idea behind this is to achieve high system throuput. Once the Processor clock speed reached its saturation, designers opted for having multiple cores. Each Core or Processor equipped with their own private cache memory. But under Chip Multiprocessor, where all the processor have access to shared memory, having respective cache memory will result with Cache Coherency Problem. In Directory Protocol, for each block of data there is a directory entry that contains a number of pointers. The purpose of this number is to mention the locations of block copies. The important advantage of directory based protocols is that they scale much better than snoopy protocols. In addition to this it has the advantage of ability to exploit arbitrary point-to-point interconnects. But mean time it also has the overhead in terms of the storage and manipulation of directory state. This paper discus different Directory Based implementation, operations along with and its implementation difficulties

Experience Capture in Shipbuilding through Computer Applications and Neural Networks

It has always been a severe loss for any establishment when an experienced hand retires or moves to another firm. The specific details of what his job/position entails will always make the work more efficient. To curtail such losses, it is possible to implement a system that takes input from a new employee regarding the challenges he/she is facing and match it to a previous occurrence where someone else held his/her chair. This system could be made possible with input through the ages from the array of individuals who managed that particular job and processing this data through a neural network that recognizes the pattern. The paper is based on data collected from traditional wooden dhow builders and some of the modern day unconventional shipyards. Since the requirements for successful implementation in such scenarios seems too steep at the moment, an alternate approach has been suggested by implementation through the design processes across multiple shipyards. The process entails the traditional value passed down through generations regarding a particular profession and analysis has been done regarding how this knowledge/experience can be captured and preserved for future generations to work upon. A series of tools including SharePoint, MATLAB, and some similar software working in tandem can be used for the design of the same. This research will provide valuable insight as to how information sharing can be applied through generations for effective application of production capabilities.Comment: Case study on knowledge transfer among employees with varying levels of experience in the field of shipbuildin

Significance of prescription elements and determination of prescription errors in psychiatry outpatient department of a tertiary care hospital

Background: Prescription is a paper or electronic document issued by licensed medical practitioner detailing the medicine or medicines to be dispensed for an individually named patient. Psychopharmacology is a rapidly growing field and psychiatrists are exposed to lots of newly introduced drugs. Therefore, this study was carried out to determine the Errors in elements of Prescription in Psychiatry Outpatient Department.Methods: A cross sectional descriptive, non-interventional study in OPD of Psychiatry Department for 12weeks, 300 prescriptions was analyzed.Results: Superscription transcription and subscription was included in almost all the prescriptions. In 244 (81.33%) signature was present. Registration number was written in 177 (59.0%) prescriptions. Only 56 (18.70%) prescriptions were written in generic name and 49 (16.34%) in capital letter. The dose was written in 241 (80.34%) of the total prescription. The frequency was written for all the drugs in 273 (91.0%) and some drugs in 46 (15.34%) and none of the drugs in 13 (4.33%) of the total prescriptions. Instructions for use was written for all the drugs in 216 (72.0%) and some drugs in 39 (13.0%) and none of the drugs in 45 (15.0%) of the total prescription. Total quantity to be dispensed was written for all the drugs in 284 (94.66%) and some drugs in 9 (3.0%) and none of the drugs in 7 (2.33%) of the total prescription. Polypharmacy was observed only in a quartile of the total prescriptions.Conclusions: The results of the present study show varied compliance to different elements of prescription writing. Low level of generic prescription observed in this study is a matter of concern. Increased generic prescribing will reduce the cost of medications and promote medication adherence

Formulation and optimization of Aceclofenac gel

The present research work is to formulate and optimize Aceclofenac gel. Fourier Transfer Infrared Spectroscopy (FT-IR) study revealed no chemical interaction between drug and polymers. The formulations were prepared by using various polymers like Carbopol 934 and HPMC K15M. The formulated gels were evaluated for several physicochemical parameters like drug-polymer interaction, pH, Viscosity, Spredability, Drug content uniformity, In vitro drug release. The formulation F9 Showed maximum drug diffusion rate. The optimization study was carried out to find out effect of two independent variable on diffusion rate at 3 hour and diffusion rate at 6 hour. Optimization was performed by the help of software DESIGN EXPERT 8.0.6 trial. From this study, it was find out that as the concentration of polymer increases, the drug release will decreases

Chemical abundance study of two strongly s-process enriched post-AGB stars in the LMC: J051213.81-693537.1 and J051848.86-700246.9

Context. This paper is part of a larger project in which we systematically study the chemical abundances of extra-galactic post-asymptotic giant branch (post-AGB) stars. The aim of our programme is to derive chemical abundances of stars covering a large range in luminosity and metallicity with the ultimate goal of testing, constraining, and improving our knowledge of the poorly understood AGB phase, especially the third dredge-up mixing processes and associated s-process nucleosynthesis. Aims. Post-AGB photospheres are dominated by atomic lines and indicate the effects of internal chemical enrichment processes over the entire stellar lifetime. In this paper, we study two carefully selected post-AGB stars: J051213.81-693537.1 and J051848.86-700246.9 in the Large Magellanic Cloud (LMC). Both objects show signs of s-process enhancement. The combination of favourable atmospheric parameters for detailed abundance studies and their known distances (and hence luminosities and initial masses) make these objects ideal probes of the AGB third dredge-up and s-process nucleosynthesis in that they provide observational constraints for theoretical AGB models. Methods. We use high-resolution optical UVES spectra to determine accurate stellar parameters and subsequently perform detailed elemental abundance studies of post-AGB stars. Additionally, we use available photometric data covering optical and IR bands to construct spectral energy distributions for reddening and luminosity determinations. We then estimate initial masses from theoretical post-AGB tracks. Results. We obtained accurate atmospheric parameters for J051213.81-693537.1 (Teff = 5875 ± 125 K, log g = 1.00 ± 0.25 dex, [Fe/H] = -0.56 ± 0.16 dex) and J051848.86-700246.9 (Teff = 6000 ± 125 K, log g = 0.50 ± 0.25 dex, [Fe/H] = -1.06 ± 0.17 dex). Both stars show extreme s-process enrichment associated with relatively low C/O ratios of 1.26 ± 0.40 and 1.29 ± 0.30 for J051213-693537.1 and J051848-700246.9, respectively. We could only derive upper limits of the lead (Pb) abundance. These upper limits show a possible very slight Pb overabundance with respect to heavy s-elements for J051213-693537.1, while J051848-700246.9 shows an upper limit of the Pb abundance similar to [hs/Fe]. A comparison with theoretical post-AGB evolutionary tracks in the HR-diagram reveals that both stars have low initial masses between 1.0 and 1.5 Mo. Conclusions. This study adds to the results obtained so far on a very limited number of s-process enriched stars in the Magellanic Clouds. With the addition of the two stars in this study, we find an increasing discrepancy between observed and predicted Pb abundances towards lower metallicities of the studied s-process rich post-AGB stars in the Magellanic Clouds. The more metal-rich J051213-693537.1 fits the theoretical Pb abundance predictions well, while the five other objects with [Fe/H] < 1, including J051848-700246.9, have much lower Pb overabundances than predicted. In all objects found so far, including the objects in this study, the C/O ratio is very moderate because of the enhancement of O as well as C. We find that all s-process rich stars in the LMC and SMC studied so far, cluster in the same region of the HR-diagram and are associated with low-mass stars with a low metallicity on average. We corroborate the published lack of correlation between the metallicity and the neutron irradiation, while the neutron exposure ([hs/ls]) is strongly correlated with the third dredge-up efficiency ([s/Fe]). These correlations seem to hold in our Galaxy as well as in the Magellanic Clouds