Timing Offset Calibration of CZTI instrument aboard ASTROSAT

The radio as well as the high energy emission mechanism in pulsars is yet not understood properly. A multi-wavelength study is likely to help in better understanding of such processes. The first Indian space-based observatory, ASTROSAT, has five instruments aboard, which cover the electromagnetic spectrum from infra-red (1300 $\AA$) to hard X-ray (380 KeV). Cadmium Zinc Telluride Imager (CZTI), one of the five instruments is a hard X-ray telescope functional over an energy range of 20-380 KeV. We aim to estimate the timing offset introduced in the data acquisition pipeline of the instrument, which will help in time alignment of high energy time series with those from two other ground-based observatories, viz. the Giant Meterwave Radio Telescope (GMRT) and the Ooty Radio Telescope (ORT). PSR B0531+21 is a well-studied pulsar with nearly aligned radio and hard X-ray pulse profiles. We use simultaneous observations of this pulsar with the ASTROSAT, the ORT and the GMRT. The pulsar was especially observed using the ORT with almost daily cadence to obtain good timing solutions. We also supplement the ORT data with archival FERMI data for estimation of timing noise. The timing offset of ASTROSAT instruments was estimated from fits to arrival time data at the ASTROSAT and the radio observatories. We estimate the offset between the GMRT and the ASTROSAT-CZTI to be -4716 $\pm$ 50 $\mu s$. The corresponding offset with the ORT was -29639 $\pm$ 50 $\mu s$. The offsets between the GMRT and Fermi-LAT -5368 $\pm$ 56 $\mu s$. (Abridged)Comment: 6 pages, 5 figures, 2 tables, Revised and Updated, accepted for publication in A&

Comparative evaluation of water budgeting parameters under different rice (Oryza sativa L.) cultivation methods

Water budgeting studies under different rice cultivation methods provides an insight into the amount of water used by the plant and percolated below the root zone for judicious water management. To undertake this study, a field experiment was conducted to estimate different soil water balance parameters under three rice (Oryza sativa L.) cultivation methods viz. Direct Seeded Rice (DSR), System of Rice Intensification (SRI) and Conventional Puddled Rice (CPR). The experiment was conducted during kharif 2013 and kharif 2014 season at research farm of Indian Council of Agricultural Research-Indian Agricultural Research Institute, New Delhi, India. In this study, the rainfall and irrigation depth, Crop Evapotranspiration (ETc), percolation beyond root zone of the crop and surface runoff during the crop growth period were accounted in water budgeting. It was observed that the percolation be-yond root zone of the crop was the highest under CPR method amounting 963 mm and 831 mm, which was about 55% and 58% of total water applied during 2013 and 2014, respectively. However, the percolation beyond root zone of the crop was the lowest under DSR method of rice cultivation amounting 367 mm and 332 mm which was 43% and 39% of total water applied during 2013 and 2014, respectively. Water loss through Etc was around 30% of total water applied in all three cultivation methods for year 2013. However, it was 59%, 46% and 43% of total water ap-plied for DSR, SRI and CPR, respectively in the year 2014.This indicates more effective utilization of total applied water in the year 2014.The study highlighted that water loss through deep percolation beyond root zone is the major factor contributing to the high water requirement in CPR and SRI methods compare to DSR method. Moreover, different soil water balance components computed in this study will be helpful for estimation of irrigation water requirement in the rice growing areas of the agro-climatic region VI (Trans-gangetic Plains) of India

Biomolecular Chemistry in Liquid Phase Separated Compartments

Biochemical processes inside the cell take place in a complex environment that is highly crowded, heterogeneous, and replete with interfaces. The recently recognized importance of biomolecular condensates in cellular organization has added new elements of complexity to our understanding of chemistry in the cell. Many of these condensates are formed by liquid-liquid phase separation (LLPS) and behave like liquid droplets. Such droplet organelles can be reproduced and studied in vitro by using coacervates and have some remarkable features, including regulated assembly, differential partitioning of macromolecules, permeability to small molecules, and a uniquely crowded environment. Here, we review the main principles of biochemical organization in model membraneless compartments. We focus on some promising in vitro coacervate model systems that aptly mimic part of the compartmentalized cellular environment. We address the physicochemical characteristics of these liquid phase separated compartments, and their impact on biomolecular chemistry and assembly. These model systems enable a systematic investigation of the role of spatiotemporal organization of biomolecules in controlling biochemical processes in the cell, and they provide crucial insights for the development of functional artificial organelles and cells

A machine learning approach for GRB detection in AstroSat CZTI data

We present a machine learning (ML) based method for automated detection of Gamma-Ray Burst (GRB) candidate events in the range 60 keV - 250 keV from the AstroSat Cadmium Zinc Telluride Imager data. We use density-based spatial clustering to detect excess power and carry out an unsupervised hierarchical clustering across all such events to identify the different light curves present in the data. This representation helps understand the instrument's sensitivity to the various GRB populations and identify the major non-astrophysical noise artefacts present in the data. We use Dynamic Time Warping (DTW) to carry out template matching, which ensures the morphological similarity of the detected events with known typical GRB light curves. DTW alleviates the need for a dense template repository often required in matched filtering like searches. The use of a similarity metric facilitates outlier detection suitable for capturing previously unmodelled events. We briefly discuss the characteristics of 35 long GRB candidates detected using the pipeline and show that with minor modifications such as adaptive binning, the method is also sensitive to short GRB events. Augmenting the existing data analysis pipeline with such ML capabilities alleviates the need for extensive manual inspection, enabling quicker response to alerts received from other observatories such as the gravitational-wave detectors

Evaluation of antibacterial potential of Trikatu churna and its ingredients: An in vitro study

Herbal medicines are being used increasingly as dietary supplements to fight or prevent common disease. The dried fruits of Piper nigrum L. (Piperaceae), Piper longum L. (Piperaceae) and rhizome of Zingiber officinale Roscoe. (Zingiberaceae) were powdered and mixed together in equiproportions to get a polyherbal formulation, Trikatu churna. The aqueous, ethanol, methanol and acetone extracts of these plant’s fruits and Trikatu churna were prepared and antibacterial activities were tested by disc diffusion method against enteric bacterial pathogens such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus epidermidis, Salmonella typhi, Salmonella typhimurium and Enterobacter aerogenes. The extracts of Piper longum, Piper nigrum and Zingiber officinale were found antibacterial to all bacterial pathogen tested. Trikatu churna exhibited potent antibacterial activity; this might be due to the multifunctional effect of all the three plant ingredients of Trikatu churna. Antibacterial activity of Trikatu churna and its ingredients was carried out in attempt to support the use of Trikatu churna for the treatment of enteric bacterial infections.Keywords: Antibacterial activity, Trikatu churna, bacterial pathogens

Evaluation of antibacterial potential of Trikatu churna and its ingredients: An in vitro study

Herbal medicines are being used increasingly as dietary supplements to fight or prevent common disease. The dried fruits of Piper nigrum L. (Piperaceae), Piper longum L. (Piperaceae) and rhizome of Zingiber officinale Roscoe. (Zingiberaceae) were powdered and mixed together in equiproportions to get a polyherbal formulation, Trikatu churna. The aqueous, ethanol, methanol and acetone extracts of these plant’s fruits and Trikatu churna were prepared and antibacterial activities were tested by disc diffusion method against enteric bacterial pathogens such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus epidermidis, Salmonella typhi, Salmonella typhimurium and Enterobacter aerogenes. The extracts of Piper longum, Piper nigrum and Zingiber officinale were found antibacterial to all bacterial pathogen tested. Trikatu churna exhibited potent antibacterial activity; this might be due to the multifunctional effect of all the three plant ingredients of Trikatu churna. Antibacterial activity of Trikatu churna and its ingredients was carried out in attempt to support the use of Trikatu churna for the treatment of enteric bacterial infections.Keywords: Antibacterial activity, Trikatu churna, bacterial pathogens

AstroStat—A VO tool for statistical analysis

AstroStat is an easy-to-use tool for performing statistical analysis on data. It has been designed to be compatible with Virtual Observatory (VO) standards thus enabling it to become an integral part of the currently available collection of VO tools. A user can load data in a variety of formats into AstroStat and perform various statistical tests using a menu driven interface. Behind the scenes, all analyses are done using the public domain statistical software—R and the output returned is presented in a neatly formatted form to the user. The analyses performable include exploratory tests, visualizations, distribution fitting, correlation & causation, hypothesis testing, multivariate analysis and clustering. The tool is available in two versions with identical interface and features—as a web service that can be run using any standard browser and as an offline application. AstroStat will provide an easy-to-use interface which can allow for both fetching data and performing power statistical analysis on them

The Search for Fast Transients with CZTI

The Cadmium Zinc Telluride Imager on AstroSat has proven to be a very effective all-sky monitor in the hard X-ray regime, detecting over three hundred GRBs and putting highly competitive upper limits on X-ray emissions from gravitational wave sources and fast radio bursts. We present the algorithms used for searching for such transient sources in CZTI data, and for calculating upper limits in case of non-detections. We introduce CIFT: the CZTI Interface for Fast Transients, a framework used to streamline these processes. We present details of 88 new GRBs detected by this framework that were previously not detected in CZTI.Comment: Accepted in the "AstroSat - 5 years" special issue of the Journal of Astrophysics and Astronomy; revised to add referee suggestions, results unchange