Absolute reflectance of a concave mirror used for astro-particle physics experiments

The absolute reflectance of a reflector and its point spread function are the key parameters of a telescope for measuring light flux. Typically, one is using low-cost technologies for producing mirrors for the needs of astro-particle physics experiments. As a rule, these are operating telescopes in open air conditions at desert or mountainous locations, for cost reasons without protecting domes. The mirrors on such telescopes are exposed to sand in strong winds, precipitation and large temperature variations. Due to weathering, their reflectance is declining within few years. In this report we describe in a great detail the application of an in-situ method to the MAGIC imaging air Cherenkov telescopes for regularly monitoring their absolute reflectance and the point spread function. Compared to similar work that was previously performed, in this report we focus on important details of light losses due to scattering. These allowed us to further refine the method and significantly improve its precision. Also, we report on an in-situ comparison of two mirror types produced with different technologies.Comment: 24 pages, 13 figures, accepted for publication in Astroparticle Physics journa

Exploring the cosmic microwave background as a composition of signals with Kolmogorov analysis

The problem of separation of different signals in the Cosmic Microwave Background (CMB) radiation using the difference in their statistics is analyzed. Considering samples of sequences which model the CMB as a superposition of signals, we show how the Kolmogorov stochasticity parameter acts as a relevant descriptor, either qualitatively or quantitatively, to distinguish the statistical properties of the cosmological and secondary signals.Comment: Mod. Phys. Lett. (in press), 13 pages, 7 figure

Solution to the ion feedback problem in Hybrid Photon Detectors and Photo Multiplier Tubes

A general solution to the positive ion feedback problem in Hybrid Photon Detectors (HPD), photo multipliers (PM) and other similar detectors was found in the insertion of a permanent electrostatic potential barrier which prevents drift of positive ions from the anode, or the first dynode, towards the photocathode. In this paper we present the method as applied to the Intevac HPD.Comment: 9 pages, 7 figures, accepted for publication in Nucl. Inst. Meth.

Gender Equality and Women's Empowerment in Academia: The Case of Armenia

The aim of the study is to analyze gender equality and women’s empowerment in Armenian academia over the past decade. For these purposes a Subjective Women’s Empowerment index has been developed as a result of data analysis from two small-sized surveys. The theoretical framework primarily draws upon the Human Capital and Subjective Well-being theories. Analysis of the statistical data has provided thought-provoking insights on the relationship of subjective and objective measures, which in some cases strongly differ. Thus, the findings on these conformities and discrepancies laid the foundation for further qualitative research analyzing the causal roots

Corporate use of social media

Despite significant and constantly increasing volume of social media use by both individuals and corporate entities, scarce scholastic attention has been paid to practices undertaken by companies and organizations in creating presence on social media, managing social media accounts and communicating with constituents on social media. New social media platforms appear regularly, attracting millions of daily visitors, however, this new type of communication media still lacks in-depth analysis, which would provide guidelines to be used by corporate entities to make their presence on social media most effective. This study makes the first step to analyze possible relationships between companies’ practices on social media and their size. It examines differences in companies’ social media adoption and activity on social media, marketing information provided on various types of social media, as well as communication strategies used, based on company size. This study finds significant differences in practices companies undertake on social media, based on company size, including social media adoption rates, activity on social media, as well as marketing information provided on the social media platforms. Overall, this study provides updated information about social media adoption by corporate entities, new insight into companies’ activity on various social media platforms, as well as overall picture of communication strategies used. This study also makes suggestions for improving companies’ representation on most popular social media platforms, making it easier for the general audience to find company social media pages, and increasing authenticity and consistency online