The Variation of Integrated Star IMFs among Galaxies

The integrated galaxial initial mass function (IGIMF) is the relevant distribution function containing the information on the distribution of stellar remnants, the number of supernovae and the chemical enrichment history of a galaxy. Since most stars form in embedded star clusters with different masses the IGIMF becomes an integral of the assumed (universal or invariant) stellar IMF over the embedded star-cluster mass function (ECMF). For a range of reasonable assumptions about the IMF and the ECMF we find the IGIMF to be steeper (containing fewer massive stars per star) than the stellar IMF, but below a few Msol it is invariant and identical to the stellar IMF for all galaxies. However, the steepening sensitively depends on the form of the ECMF in the low-mass regime. Furthermore, observations indicate a relation between the star formation rate of a galaxy and the most massive young stellar cluster in it. The assumption that this cluster mass marks the upper end of a young-cluster mass function leads to a connection of the star formation rate and the slope of the IGIMF above a few Msol. The IGIMF varies with the star formation history of a galaxy. Notably, large variations of the IGIMF are evident for dE, dIrr and LSB galaxies with a small to modest stellar mass. We find that for any galaxy the number of supernovae per star (NSNS) is suppressed relative to that expected for a Salpeter IMF. Dwarf galaxies have a smaller NSNS compared to massive galaxies. For dwarf galaxies the NSNS varies substantially depending on the galaxy assembly history and the assumptions made about the low-mass end of the ECMF. The findings presented here may be of some consequence for the cosmological evolution of the number of supernovae per low-mass star and the chemical enrichment of galaxies of different mass.Comment: 27 pages, accepted for publication by Ap

To punish first and reward second: Values determine how reward and punishment affect risk-taking behavior

The current study investigated whether manipulating participants’ pre-exposure to reward and punishment affects the extent to which sensation seeking and values predict risk-taking behavior. Participants (n = 195) were randomly allocated to one of two conditions, defined by the order at which they were rewarded or punished for risk-taking behavior. Risk-taking behavior was measured in both conditions using the Balloon Analogue Risk Test, however this was set-up such that participants in group 1 were rewarded for risk-taking behavior prior to being punished, whereas participants in group 2 were punished for risk-taking behavior prior to being rewarded. Participants also completed questionnaires designed to measure sensation seeking and the values of ‘stimulation’ (the need for novelty and excitement) and ‘hedonism’ (the need for sensuous pleasure). It was found that stimulation predicted risk taking behavior in the ‘reward-then-punishment’ condition, whereas hedonism predicted risk-taking behavior in the ‘punishment-then-reward’ condition. Sensation-seeking was found to be an indirect predictor of risk-taking behavior in both conditions. It is tentatively concluded that the extent to which an individual’s risk-taking behavior is guided by their values (hedonism, stimulation) largely depends on their prior exposure to the order of contingent reward and punishment

Physical Parameters for the Afterglows of GRB 980703, 990123, 990510, and 991216 Determined from Modeling of Multi-Frequency Data

We model the radio, optical, and X-ray emission for the afterglows of GRB 980703, 990123, 990510, and 991216, within the framework of relativistic jets, to determine their physical parameters. The models that yield acceptable fits to the data have jet energies mostly between 10^{50} to 10^{51} erg and initial opening angles between 1 deg and 4 deg. The external medium density is uncertain by at least one order of magnitude in each case, being around 10^{-3}/cm^3 for GRB 980703 and 990123, ~0.1/cm^3 for GRB 990510, and ~3/cm^3 for GRB 991216. If the jets are uniform (i.e. there are no angular gradients of the energy per solid angle) then the 20 keV -- 1 MeV radiative efficiency during the GRB phase must have been at least 2-3% for GRB 990510, 20% for GRB 990123, and 30% for GRB 991216.Comment: accepted for publication by the ApJ, vol. 554. 11 pages, color figures. Last figures replaced with probability distributions of model parameter

CCD photometric and mass function study of 9 young Large Magellanic Cloud star clusters

We present CCD photometric and mass function study of 9 young Large Magellanic Cloud star clusters namely NGC 1767, NGC 1994, NGC 2002, NGC 2003, NGC 2006, SL 538, NGC 2011, NGC 2098 and NGC 2136. The BVRI data reaching down to V ~ 21 mag, are collected from 3.5-meter NTT/EFOSC2 in sub-arcsec seeing conditions. For NGC 1767, NGC 1994, NGC 2002, NGC 2003, NGC 2011 and NGC 2136, broad band photometric CCD data are presented for the first time. Seven of the 9 clusters have ages between 16 to 25 Myr while remaining two clusters have ages $32\pm4$ Myr (NGC 2098) and $90\pm10$ Myr (NGC 2136). For 7 younger clusters, the age estimates based on a recent model and the integrated spectra are found to be systematically lower ($\sim$ 10 Myr) from the present estimate. In the mass range of $\sim 2 - 12$ $M_{\odot}$, the MF slopes for 8 out of nine clusters were found to be similar with the value of $\gamma$ ranging from $-1.90\pm0.16$ to $-2.28\pm0.21$. For NGC 1767 it is flatter with $\gamma = -1.23\pm0.27$. Mass segregation effects are observed for NGC 2002, NGC 2006, NGC 2136 and NGC 2098. This is consistent with the findings of Kontizas et al. for NGC 2098. Presence of mass segregation in these clusters could be an imprint of star formation process as their ages are significantly smaller than their dynamical evolution time. Mean MF slope of $\gamma = -2.22\pm0.16$ derived for a sample of 25 young ($\le 100$ Myr) dynamically unevolved LMC stellar systems provide support for the universality of IMF in the intermediate mass range $\sim 2-12 M_{\odot}$.Comment: To appear in MNRA

DESTINATION BRANDING- A CURRENT SOCIAL MEDIA APPROACH

Destinations are marketed in various ways, the best medium being Destination Branding. As it is today, a lot of cities and states have formed internationally renowned brand names through various innovative campaigns and the help of Brand Ambassadors, creative taglines, vibrant ads & billboard displays and an effective far-reaching social media campaign. The best example can be that of the 23 Mediterranean Countries that used Facebook for an effective Destination Branding. Social media is considered as one of the most important forms of communication in this modern era of technology, the use of Facebook and the micro-blogging website, Twitter has seen a staggering rise. This conceptual research focuses on the process of Destination Branding using two key pillars of Social Media, which is very new, quite effective in terms of reach and the best of all, free! The two media are Instagram and Snapchat. Using the Case Study approach, cities like Lyon, Amsterdam, and Philadelphia have been studied their campaigns have been immensely successful, as revealed by the numbers of people reached by the Instagram campaigns. The research also consists of suggestions and tactics that Destination Marketers and Branders can use as campaigns on Snapchat, to make effective use of opportunities in Real-Time Marketing. The objective being to bring out the fact that today, a Brand does not really need a famous person as an Ambassador and that Hashtags are the new-age way of search engines and how these strategies can be used by small cities in India. The research also focuses on giving suggestions about how Goa and Bangalore can use hashtags on Instagram and Snapchat effectively to promote the brands that they stand for

Experimental Study on the Effect of Cement and Sand Replacement with Red Mud and Quarry Dust in Cement Concrete Pavements

The main objective of the project is experimental study of the possibility of utilizing the waste red mud (bauxite residue) and quarry dust in cement concrete. Red mud is a by-product produced in the process of extraction of aluminium from bauxite. The red mud generated by this process is highly alkaline with a pH usually ranging from 10 to 12. It leads to serious environmental problems. Worldwide there are approximately 80 to 90 million tons of red mud is being generated every year. The production of 1 ton aluminium generates 1-2 tonnes of red mud. The storage of red mud is economically and environmentally problematic due to the risk of contamination of natural resources and living organisms. Red mud can be used in replacement of cement in concrete. The quarry dust which is available from local resources can be used as a replacement of river sand in a conventional concrete pavements. This study aims at describing such utilization and their effective usage in concrete. Experiments have been conducted under laboratory conditions to assess the compressive strength and flexural strength of the concrete cubes made of red mud and quarry dust. By conducting the model tests we can replace the 15% of cement with red mud and 30% of sand with quarry dust

A comparative study of the efficacy and tolerability of parenteral ceftriaxone and cefotaxime in pediatric population for acute bacillary dysentery in a tertiary care hospital

Background: Diarrheal disorders in childhood account for a large proportion (18%) of childhood mortality. Among diarrheal diseases, dysentery is a major cause of childhood morbidity and mortality, especially in developing countries.Methods: This is an open labelled, prospective, randomised, comparative study carried out at Dr. B. R. Ambedkar Medical College Hospital, Bangalore from November 2014 to November 2015 after Institutional Ethics Committee approval. A total of 80 Paediatric patients who met the inclusion criteria were included in the study after taking written informed consent from parents and assigned into two groups, Group A- Inj. Ceftriaxone (50-100mg/kg/day) and Group B- Inj. Cefotaxime (100 mg/kg/day) in divided doses for a period of 3-5 days based on requirement.Results: In this study, Cefotaxime was non inferior to Ceftriaxone as the Mean Duration of Hospitalisation was 3.30±0.72 days in Group A and 3.30± 0.72 days in Group B with p value of 1.000, showing no statistically significant difference. Both were well tolerated without any reports of ADR (Adverse Drug Reaction).Conclusions: In this study shows that Inj. Cefotaxime is equally efficacious and well tolerated as Inj. Ceftriaxone in the treatment of Acute Bacillary Dysentery in paediatric patients

The star formation history of the Local Group dwarf elliptical galaxy NGC 185: II. Gradients in the stellar population

The star formation history of the dE NGC 185, together with its spatial variations, has been investigated using new ground-based $H_\alpha$ and $BVI$ photometry, and synthetic color--magnitude diagrams (CMDs). We find that the bulk of the stars were formed in NGC 185 at an early epoch of its evolution. After that, the star formation proceeded at a low rate until the recent past, the age of the most recent traces of star formation activity detected in the galaxy being some 100 Myr. The star formation rate, $\psi(t)$ for old and intermediate ages shows a gradient in the sense of taking smaller values for higher galactocentric radii. Moreover, recent star formation is detected in the central $150 \times 90$ pc$^2$ only, where the youngest, 100 Myr old population is found. The luminous blue {\it stars} discovered by Baade (1951) in the center of NGC 185 are discussed using new CCD images in $B$ and Baade's original photographic plates, reaching the conclusion that most of them are in fact star clusters. A consistent picture arises in which the gas observed in the central region of NGC 185 would have an internal origin. The rate at which evolved stars return gas to the ISM is enough to seed the recent star formation observed in the center of the galaxy and the SN rate is probably low enough to allow the galaxy to retain the gas not used in the new stellar generations.Comment: 34 pages, 17 figures, 5 Tables, to be published in AJ October 9

Photometric variability of four coronally active stars

We present photometric observations of four stars that are optical counterparts of soft X-ray/EUV sources, namely 1ES 0829+15.9, 1ES0920-13.6, 2RE J110159+223509 and 1ES 1737+61.2. We have discovered periodic variability in two of the stars, viz., MCC 527 (1ES 0829+15.9; Period=0d.828±0.0047) and HD 81032 (1ES 0920-13.6; Period=~57.02±0.560 days). HD 95559 (2RE J110159+223509) is found to show a period of 3d. HD 160934 (1ES1737+61.2) also shows photometric variability but needs to be monitored further for finding its period. These stars most likely belong to the class of chromospherically active stars

Optical and X-ray studies of chromospherically active stars : FR Cancri, HD 95559 and LO Pegasi

We present a multiwavelength study of three chromospherically active stars, namely FR Cnc (= BD +16\degr 1753), HD 95559 and LO Peg (=BD +22\degr 4409), including newly obtained optical photometry, low-resolution optical spectroscopy for FR Cnc, as well as archival IR and X-ray observations. The BVR photometry carried out during the years 2001 - 2004 has found significant photometric variability to be present in all three stars. For FR Cnc, a photometric period $0.8267 \pm 0.0004 \rm {d}$ has been established. The strong variation in the phase and amplitude of the FR Cnc light curves when folded on this period implies the presence of evolving and migrating spots or i spot groups on its surface. Two independent spots with migration periods of 0.97 and 0.93 years respectively are inferred. The photometry of HD 95559 suggests the formation of a spot (group) during the interval of our observations. We infer the existence of two independent spots or groups in the photosphere of LO Peg, one of which has a migration period of 1.12 years. The optical spectroscopy of FR Cnc carried out during 2002-2003, reveals the presence of strong and variable Ca II H and K, H$_\beta$ and $H_{\alpha}$ emission features indicative of high level of chromospheric activity. The value of 5.3 for the ratio of the excess emission in $H_{\alpha}$ to $H_{\beta}$, $E_{H_{\alpha}}/E_{H_{\beta}}$, suggests that the chromospheric emission may arise from an extended off-limb region. We have also analyzed archival X-ray observations of HD 95559 and LO Peg carried out by with the ROSAT observatory. The best fit models to their X-ray spectra imply the presence of two coronal plasma components of differing temperatures and with sub-solar metal abundances.Comment: 40 pages, 11 figures, 6 tables, Accepted for the publication in A