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349 results on '"Dimitrova S"'

110. Exact Solution of the Isovector Neutron-Proton Pairing Hamiltonian

Author

Dukelsky, Jorge, Gueorguiev, V. G., Van Isacker, P., Dimitrova, S., Errea, Beatriz, Lerma H., Sergio, Dukelsky, Jorge, Gueorguiev, V. G., Van Isacker, P., Dimitrova, S., Errea, Beatriz, and Lerma H., Sergio

Abstract

The complete exact solution of the T=1 neutron-proton pairing Hamiltonian is presented in the context of the SO(5) Richardson-Gaudin model with nondegenerate single-particle levels and including isospin symmetry-breaking terms. The power of the method is illustrated with a numerical calculation for 64Ge for a pf+g9/2 model space which is out of reach of modern shell-model codes.

Published
2006

116. The density matrix renormalization group in nuclear physics: a status report

Author

National Science Foundation (US), Ministerio de Educación y Ciencia (España), North Atlantic Treaty Organization, Pittel, S., Dukelsky, Jorge, Dimitrova, S., Stoitsov, M., National Science Foundation (US), Ministerio de Educación y Ciencia (España), North Atlantic Treaty Organization, Pittel, S., Dukelsky, Jorge, Dimitrova, S., and Stoitsov, M.

Abstract

We report on the current status of recent efforts to develop the Density Matrix Renormalization Group method for use in large-scale nuclear shell-model calculations.

Published
2003

119. Multistep direct mechanism in the (p→,He3) inclusive reaction onCo59andNb93at incident energies between 100 and 160 MeV

Author

Cowley, A. A., primary, Bezuidenhout, J., additional, Dimitrova, S. S., additional, Hodgson, P. E., additional, Förtsch, S. V., additional, Hillhouse, G. C., additional, Jacobs, N. M., additional, Neveling, R., additional, Smit, F. D., additional, Stander, J. A., additional, Steyn, G. F., additional, and Zyl, J. J. van, additional

Published
2007
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120. RANK-TWO RICHARDSON-GAUDIN MODELS

Author

DUKELSKY, J., primary, LERMA H., S., additional, ERREA, B., additional, PITTEL, S., additional, DIMITROVA, S., additional, GUEORGUIEV, V. G., additional, and VAN ISACKER, P., additional

Published
2006
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124. Analysis of Changes of Cardiological Parameters at Middle Latitude Region in Relation to Geomagnetic Disturbances and Cosmic Ray Variations.

Author

Papailiou, M., Dimitrova, S., Babayev, E. S., and Mavromichalaki, H.

Subjects
*CARDIOLOGY, *GEOMAGNETISM, *ASTROPHYSICAL radiation, *IONIZING radiation, *ELECTROCARDIOGRAPHY
Abstract

Collaborating scientific groups from Athens (Greece), Baku (Azerbaijan) and Sofia (Bulgaria) have conducted a research work on the possible effects of geomagnetic field disturbances (GMF) and cosmic ray intensity (CRI) variations on human homeostasis, particularly, the cardio-health state. Electrocardiograms (ECGs) of seven functionally healthy persons were digitally registered at the joint Laboratory of Heliobiology located in the Medical Centre INAM, Baku, on working days and Saturdays. Heart rate values, estimated from ECGs, were analysed in relation to daily values of CRI, as measured by the Neutron Monitor of the University of Athens and daily variations of Dst and Ap geomagnetic indices and some significant results had been revealed in previous studies. Researches were continued by study of additional cardiologic parameters estimated from the same ECG data. In this study digital data of RR interval (the time elapsing between two consecutive R waves in the ECG), namely RRminimum, RRmaximum and RRaverage were analyzed taking into consideration different levels of GMF disturbances (estimated through variations of Dst and Ap indices) and cosmic ray activity (through CRI variations). The data refer to the time period 15 July 2006–31 March 2008. Variations of RR intervals show connection to GMF disturbances and CRI variations. The revealed effects are more pronounced for high levels of geomagnetic activity (when geomagnetic storms occur) and large CRI decreases as well as on the days before and after these variations. [ABSTRACT FROM AUTHOR]

Published
2010
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130. CORRELATED OVERLAP FUNCTIONS AND NUCLEON REMOVAL REACTIONS FROM 16O.

Author

GAIDAROV, M. K., IVANOV, M. V., ANTONOV, A. N., PAVLOVA, K. A., DIMITROVA, S. S., STOITSOV, M. V., GIUSTI, C., Van Neck, D., and MÜTHER, H.

Subjects
PARTICLES (Nuclear physics), NUCLEAR reactions, BODY density, NUCLEAR physics experiments, NUCLEAR fusion
Published
2000

131. Multistep direct mechanism in the(p→,3He)inclusive reactionon59Coand93Nb at an incident energy of 100 MeV

Author

Cowley, A. A., primary, Steyn, G. F., additional, Dimitrova, S. S., additional, Hodgson, P. E., additional, Arendse, G. J., additional, Förtsch, S. V., additional, Hillhouse, G. C., additional, Lawrie, J. J., additional, Neveling, R., additional, Richter, W. A., additional, Stander, J. A., additional, and Wyngaardt, S. M., additional

Published
2000
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133. Pre-equilibrium mechanisms in the 93Nb(p,α) inclusive reaction at incident energies from 65 to 160 MeV.

Author

Dimitrova, S. S., Cowley, A. A., Zemlyanaya, E. V., and Lukyanov, K. V.

Subjects
*QUANTUM mechanics, *REACTION mechanisms (Chemistry), *PARTICLE emissions, *SPECTRAL energy distribution, *BORN approximation, NIOBIUM isotopes
Abstract

The reaction mechanism of pre-equilibrium proton-induced α-particle emission from 93Nb at an incident energy of 100 MeV was investigated with polarized projectiles. A formalism based on the statistical multistep direct emission model of Feshbach, Kerman, and Koonin was found to give a reasonably good reproduction of cross section and analyzing power angular distributions at various emission energies. Existing experimental distributions for the same reaction at an incident energy of 65 MeV were also analyzed with the same model. The incident-energy variation from 65 MeV up to 160 MeV was found to be consistent with the predictions of the basic model. However, whereas knockout of an α cluster is the dominant reaction mechanism in the final stage at the lowest and highest incident energies, at 100 MeV a pickup process competes with comparable intensity in yield. [ABSTRACT FROM AUTHOR]

Published
2014
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134. Inclusive reaction 93Nb(p,α) at an incident energy of 160 MeV.

Author

Dimitrova, S. S., Cowley, A. A., van Zyl, J. J., Zemlyanaya, E. V., and Lukyanov, K. V.

Subjects
*ANGULAR distribution (Nuclear physics), *DISTRIBUTION (Probability theory), *EMISSIONS (Air pollution), *KINEMATICS, *MATHEMATICAL continuum
Abstract

The inclusive 93Nb(p,α) reaction to the continuum was investigated at an incident energy of 160 MeV. Emission-energy angular distributions for cross sections as well as analyzing powers were explored. A range of scattering angles from 15° to 60° (lab.) was covered and α-particle emission energies from ≈30 MeV to the kinematic limit were measured. As in our earlier work, the experimental distributions were compared with a multistep direct theory combined with a knockout reaction mechanism as the terminating step in the a-particle emission. Reasonable agreement between the theoretical predictions and the experimental double-differential cross section and analyzing-power angular distributions were obtained. [ABSTRACT FROM AUTHOR]

Published
2014
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138. Measurement of Methane and Other Atmospheric Pollutants Emitted by Flooded Paddy Fields

Author

Dimitrova Svetla

Subjects
air pollution, flooded paddy fields, variety peculiarities, Environmental sciences, GE1-350
Abstract

The increase of methane concentration has been established during the last decades. This gas has a relative potential for thermal absorption, 30 times higher than CO2, which means that it is more active in the interaction with the ozone and its blocking. About 70% of the global total emission of methane in the atmosphere is of biogenic origin. Flooded paddy fields are one of the main sources of atmosphere pollutions with methane. Irrigation of rice fields by overflowing reduces the feeding of the ground with oxygen from the air. This in turn affects the fermentation of organic substances in the ground. Methane is the final product in this process. The measurement was performed in the phase of rice earing by an authorized laboratory associated to the Executive Environment Agency at the Ministry of Waters and Environment by means of methods specified by the Ministry. The concentrations of damaging substances were automatically measured at every 60 min for SO2, NO2, NO, and at every 30 min for H2S, CH4, NMHC, CO, and NH3. The obtained results prove that the concentrations of NO, H2S, CH4 and NMHC exceed all limits. The quantity of gases is influenced by the variety peculiarities of the culture (the roots mass, the total bio-mass and the running metabolic processes).

Published
2018
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139. Antidepressant Effect and Recognition Memory Improvement of Two Novel Plant Extract Combinations - Antistress I and Anti-stress II on Rats Subjected to a Model of Mild Chronic Stress

Author

Kandilarov Ilin K., Zlatanova Hristina I., Georgieva-Kotetarova Maria T., Kostadinova Ivanka I., Katsarova Mariana N., Dimitrova Stela Z., Lukanov Ludmil K., and Sadakov Ferit

Subjects
chronic stress, forced swim test, novel object recognition test, plant extract combinations, serratula coronata, Medicine
Abstract

Background: Chronic stress is one of the main factors which lead to depression – a psychiatric disorder affecting millions of people and predicted to be the second ranked cause of premature death in 2020. Depression is often associated with cognitive disturbances and memory deficit. Plant based therapy could be effective in the treatment of mild to moderate depression due to its low level of adverse reaction, its good tolerability and compliance.

Published
2018
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