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296 results on '"Safonova, Margarita"'

51. Motion of a Vector Particle in a Curved Spacetime. I. Lagrangian Approach

Author

Turakulov, Zafar and Safonova, Margarita

Subjects
General Relativity and Quantum Cosmology
Abstract

From the simple Lagrangian the equations of motion for the particle with spin are derived. The spin is shown to be conserved on the particle world-line. In the absence of a spin the equation coincides with that of a geodesic. The equations of motion are valid for massless particles as well, since mass does not enter the equations explicitely., Comment: 6 pages, uses mpla1.sty, published in MPLA, replaced with corrected typos

Published
2001
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52. Microlensing by natural wormholes: theory and simulations

Author

Safonova, Margarita, Torres, Diego F., and Romero, Gustavo E.

Subjects
General Relativity and Quantum Cosmology, Astrophysics, High Energy Physics - Theory
Abstract

We provide an in depth study of the theoretical peculiarities that arise in effective negative mass lensing, both for the case of a point mass lens and source, and for extended source situations. We describe novel observational signatures arising in the case of a source lensed by a negative mass. We show that a negative mass lens produces total or partial eclipse of the source in the umbra region and also show that the usual Shapiro time delay is replaced with an equivalent time gain. We describe these features both theoretically, as well as through numerical simulations. We provide negative mass microlensing simulations for various intensity profiles and discuss the differences between them. The light curves for microlensing events are presented and contrasted with those due to lensing produced by normal matter. Presence or absence of these features in the observed microlensing events can shed light on the existence of natural wormholes in the Universe., Comment: 16 pages, 24 postscript figures (3 coloured), revtex style, submitted to Phys. Rev. D

Published
2001
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53. Macrolensing signatures of large-scale violations of the weak energy condition

Author

Safonova, Margarita, Torres, Diego F., and Romero, Gustavo E.

Subjects
Astrophysics, General Relativity and Quantum Cosmology, High Energy Physics - Theory
Abstract

We present a set of simulations of the macrolensing effects produced by large-scale cosmological violations of the energy conditions. These simulations show how the appearance of a background field of galaxies is affected when lensed by a region with an energy density equivalent to a negative mass ranging from $10^{12}$ to $10^{17}$ solar masses. We compare with the macrolensing results of equal amounts of positive mass, and show that, contrary to the usual case where tangential arc-like structures are expected, there appear radial arcs-runaway filaments-and a central void. These results make the cosmological macrolensing produced by space-time domains where the weak energy conditions is violated, observationally distinguishable from standard regions. Whether large domains with negative energy density indeed exist in the universe can now be decided by future observations of deep fields., Comment: 10 pages with 9 Postscript figures

Published
2001
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55. Development of Raspberry Pi-based Processing Unit for UV Photon-Counting Detectors.

Author

Chandra P., Bharat, Nair, B. G., Ghatul, Shubham Jankiram, Babu S, Mahesh, Jain, Shubhangi, Rai, Richa, Mohan, Rekhesh, Safonova, Margarita, and Murthy, Jayant

Subjects
RASPBERRY industry, PHOTONS, INFRARED radiation, ASTRONOMY, DETECTORS
Abstract

In ultraviolet (UV) astronomical observations, photons from the sources are very few compared to the visible or infrared (IR) wavelength ranges. Detectors operating in the UV usually employ a photon-counting mode of operation. These detectors usually have an image intensifier sensitive to UV photons and a readout mechanism that employs photon counting. The development of readouts for these detectors is resource-intensive and expensive. In this paper, we describe the development of a low-cost UV photon-counting detector processing unit that employs a Raspberry Pi (RPi) with its built-in readout to perform the photon-counting operation. Our system can operate in both 3 × 3 and 5 × 5 window modes at 30 frames per second (fps). The system can be built quickly from readily available custom-off-the-shelf (COTS) components and is thus used in inexpensive CubeSats or small satellite missions. [ABSTRACT FROM AUTHOR]

Published
2024
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57. Results from the worldwide coma morphology campaign for comet ISON (C/2012 S1)

Author

Samarasinha, Nalin H., Mueller, Beatrice E.A., Knight, Matthew M., Farnham, Tony L., Briol, John, Brosch, Noah, Caruso, John, Gao, Xing, Gomez, Edward, Lister, Tim, Hergenrother, Carl, Hoban, Susan, Prouty, Roy, Holloway, Mike, Howes, Nick, Guido, Ernesto, Hui, Man-To, Jones, Joseph H., Penland, Tyler B., Thomas, Samuel R., Wyrosdick, Jim, Kiselev, Nikolai, Ivanova, Aleksandra V., Kaye, Thomas G., Eluo, Jean-Baptist Kikwaya, Lau, Betty P.S., Lin, Zhong-Yi, Martin, José Luis, Moskvitin, Alexander S., Nicolini, Martino, Ottum, Brian D., Pruzenski, Chris, Vogel, David C., Kellett, Leo, Rapson, Valerie, Schmid, Joel, Doyle, Brandon, Dimino, Frank, Carlino, Stephanie, Safonova, Margarita, Murthy, Jayant, Sutaria, Firoza, Schleicher, David G., Snodgrass, Colin, Tezcan, Cihan T., Yorukoglu, Onur, Trowbridge, David, Whitmer, Dennis, and Ye, Quan-Zhi

Published
2015
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64. TINI–a mission for FUV spectroscopy of extended objects

Author

Diebold, Sebastian J., primary, Barnstedt, Jürgen, additional, Chandra, Bharat, additional, Conti, Lauro, additional, Ghatul, Shubham, additional, Kappelmann, Norbert, additional, Mohan, Rekhesh, additional, Murthy, Jayant, additional, Nair, Binukumar G., additional, Prabha, Shanti, additional, Rai, Richa, additional, Safonova, Margarita, additional, Stelzer, Beate, additional, and Werner, Klaus, additional

Published
2022
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66. The near ultraviolet transient surveyor (NUTS): An ultraviolet telescope to observe variable sources

Author

Ambily, S., primary, Sarpotdar, Mayuresh, additional, Mathew, Joice, additional, Nair, Binukumar G., additional, Sreejith, A. G., additional, Nirmal, K., additional, Murthy, Jayant, additional, Safonova, Margarita, additional, Mohan, Rekhesh, additional, Aggarval, Vinod Kumar, additional, Nagabhushanam, S., additional, and Jeeragal, Sachin, additional

Published
2022
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74. Towards a BRICS Optical Transient Network (BRICS-OTN)

Author

BUCKLEY, DAVID A.H., primary, MCBRIDE, VANESSA A., additional, ALMEIDA, ULISSES BARRES DE, additional, SHUSTOV, BORIS, additional, POZANENKO, ALEXEI, additional, LUTOVINOV, ALEXANDER, additional, OMAR, AMITESH, additional, MURTHY, JAYANT, additional, SAFONOVA, MARGARITA, additional, LIU, JIFENG, additional, and SORIA, ROBERTO, additional

Published
2021
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78. Postulating exoplanetary habitability via a novel anomaly detection method.

Author

Sarkar, Jyotirmoy, Bhatia, Kartik, Saha, Snehanshu, Safonova, Margarita, and Sarkar, Santonu

Subjects
HABITABLE planets, INTRUSION detection systems (Computer security), AXIOMS, PLANETS, EXTRASOLAR planets
Abstract

A profound shift in the study of cosmology came with the discovery of thousands of exoplanets and the possibility of the existence of billions of them in our Galaxy. The biggest goal in these searches is whether there are other life-harbouring planets. However, the question which of these detected planets are habitable, potentially-habitable, or maybe even inhabited, is still not answered. Some potentially habitable exoplanets have been hypothesised, but since Earth is the only known habitable planet, measures of habitability are necessarily determined with Earth as the reference. Several recent works introduced new habitability metrics based on optimisation methods. Classification of potentially habitable exoplanets using supervised learning is another emerging area of study. However, both modelling and supervised learning approaches suffer from drawbacks. We propose an anomaly detection method, the multi-stage memetic algorithm (MSMA), to detect anomalies and extend it to an unsupervised clustering algorithm multi-stage multi-version memetic clustering algorithm to use it to detect potentially habitable exoplanets as anomalies. The algorithm is based on the postulate that Earth is an anomaly, with the possibility of existence of few other anomalies among thousands of data points. We describe an MSMA-based clustering approach with a novel distance function to detect habitable candidates as anomalies (including Earth). The results are cross-matched with the Planetary Habitability Laboratory-habitable exoplanet catalogue (PHL-HEC) of the PHL with both optimistic and conservative lists of potentially habitable exoplanets. [ABSTRACT FROM AUTHOR]

Published
2022
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80. Taxes Harmonization Features in the European Union Countries

Author

SAFONOVA, Margarita F., REZNİCHENKO, Dmitry S., MELNİCHUK, Marina V., KARAEV, Alan K., and LİTVİNOVA, Svetlana F.

Subjects
economy,taxes,tax harmonization,the tax system regulation, economy, lcsh:HB71-74, the tax system regulation, lcsh:Economics as a science, lcsh:Business, tax harmonization, lcsh:HF5001-6182, taxes
Abstract

Today the most developed integration association is the European Union, which main predecessor is the European Economic Community that was created in 1957. The challenge on the today’s agenda in the EU is the formation and strengthening of the economic, monetary and political union of the countries - members. The integration within the EU affects almost all relationship parties of the states - the EU members - politics, economics, social and cultural spheres. To indicate this process the term “tax harmonization” is used in the EU. The driving force and the motivation incentive of the taxation harmonization in the Member States of the European Union are the processes of the deepening of the international economic integration. At the same time, the tax systems rapprochement of the states involved in the integration association has the opposite stimulating effect on the further development of the integration processes in other areas. The research relevance is caused by the importance and special role of tax harmonization in the framework of the European economic integration deepening, the development of the EU united internal market, the economic and currency union formation in the EU. The study objectives is the determination of the tax harmonization and justification of its need for the integration association at the mature stages of its development, the identification and analysis of the factors affecting the pro- process of tax harmonization in the European Union countries.

Published
2016

82. The spectroscopic investigation of nebular gas(SING): a dedicated NUV spectrograph to study extended objects

Author

Chandra, Bharat P., primary, Nair, Binukumar G., additional, Suresh, Ambily, additional, Prabha, Shanti, additional, Mathew, Joice, additional, Kaipachery, Nirmal, additional, Sarpotdar, Mayuresh N., additional, Mohan, Rekhesh, additional, Safonova, Margarita, additional, Sripadmanaban, Sriram, additional, and Murthy, Jayant, additional

Published
2020
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84. Prospect for UV observations from the Moon. III. Assembly and ground calibration of Lunar Ultraviolet Cosmic Imager (LUCI)

Author

Mathew, Joice, primary, Nair, B. G., additional, Safonova, Margarita, additional, Sriram, S., additional, Prakash, Ajin, additional, Sarpotdar, Mayuresh, additional, Ambily, S., additional, Nirmal, K., additional, Sreejith, A. G., additional, Murthy, Jayant, additional, Kamath, P. U., additional, Kathiravan, S., additional, Prasad, B. R., additional, Brosch, Noah, additional, Kappelmann, Norbert, additional, Gadde, Nirmal Suraj, additional, and Narayan, Rahul, additional

Published
2019
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88. Opto-mechanical assembly and ground calibration of LUCI

Author

Mathew, Joice, primary, Nair, Binukumar G., primary, Prakash, Ajin, primary, Sarpotdar, Mayuresh N., primary, Suresh, Ambily, primary, K., Nirmal, primary, Aickara Gopinathan, Sreejith, primary, Safonova, Margarita, primary, Murthy, Jayant, primary, Brosch, Noah, primary, S., Sriram, primary, and Kamath, P. U., primary

Published
2018
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89. PIONS: a CubeSat imager to observe variable UV sources

Author

Suresh, Ambily, primary, Mathew, Joice, primary, Sarpotdar, Mayuresh N., primary, Aggarval, Vinod K., primary, Nagabhushanam, S., primary, Jeeragal, Sachin, primary, Rao, Divya A., primary, Kaipachery, Nirmal, primary, Nair, Binukumar G., primary, Safonova, Margarita, primary, Murthy, Jayant, primary, and Aickara Gopinathan, Sreejith, primary

Published
2018
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