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Institution

Bulgarian Academy of Sciences

GovernmentSofia, Bulgaria
About: Bulgarian Academy of Sciences is a government organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Coupling constant & Catalysis. The organization has 17989 authors who have published 36276 publications receiving 642820 citations. The organization is also known as: Bulgarian Academy of Sciences,簡稱:BAS & Balgarska Akademiya na Naukite.


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Journal ArticleDOI
TL;DR: In this paper, the transit times of the exoplanet WASP-12 b do not follow a linear ephemeris with a 5σ confidence level, and they may be approximated with a quadratic ephemerISR that gives a change rate in the orbital period of (−2.56 ± 0.40) × 10-2 s yr-1.
Abstract: Aims. Most hot Jupiters are expected to spiral in toward their host stars because the angular momentum of the orbital motion is transferred to the stellar spin. Their orbits can also precess as a result of planet-star interactions. Calculations show that both effects might be detected for the very-hot exoplanet WASP-12 b using the method of precise transit-timing over a time span of about 10 yr. Methods. We acquired new precise light curves for 29 transits of WASP-12 b, spannning four observing seasons from November 2012 to February 2016. New mid-transit times, together with those from the literature, were used to refine the transit ephemeris and analyze the timing residuals.Results. We find that the transit times of WASP-12 b do not follow a linear ephemeris with a 5σ confidence level. They may be approximated with a quadratic ephemeris that gives a change rate in the orbital period of (−2.56 ± 0.40) × 10-2 s yr-1 . The tidal quality parameter of the host star was found to be equal to 2.5 × 105 , which is similar to theoretical predictions for Sun-like stars. We also considered a model in which the observed timing residuals are interpreted as a result of the apsidal precession. We find, however, that this model is statistically less probable than the orbital decay.

108 citations

Journal ArticleDOI
TL;DR: Visible light-absorbing cationic water-soluble gallium(III) phthalocyanines peripherally substituted with four and eight methylpyridyloxy groups were synthesized and investigated as antimicrobial photodynamic sensitizers.
Abstract: Visible light-absorbing cationic water-soluble gallium(III) phthalocyanines (GaPcs) peripherally substituted with four and eight methylpyridyloxy groups were synthesized and investigated as antimicrobial photodynamic sensitizers The inserted large gallium ion in the phthalocyanine ligand is axially substituted by one hydroxyl group which prevents aggregation of the complexes in aqueous solution The cellular uptake and the photodynamic activity for the representative strains of the Gram positive bacteria methicillin-resistant Staphylococcus aureus(MRSA) and Enterococcus faecalis, of the Gram negative bacterium Pseudomonas aeruginosa and of the fungus Candida albicans in planktonic phase were studied The tetra-methylpyridyloxy substituted GaPc1 showed lower cellular uptake compared to the octa-methylpyridyloxy substituted GaPc2 The photodynamic activity of the GaPcs was studied in comparison to methylene blue (MB) and a photodynamically active Zn(II)-phthalocyanine with the same substitution (ZnPcMe) Photodynamic treatment with 30 μM GaPc1 at mild light conditions (50 J cm−2, 60 mW cm−2) resulted in a high photoinactivation of the microorganisms in the planktonic phase nevertheless the dark toxicity of GaPc1 towards MRSA and E faecalis GaPcs against fungal biofilm grown on polymethylmethacrylate (PMMC) resin showed a complete inactivation at a higher concentration of GaPc2 (60 μM) and of the referent sensitizer ZnPcMe However, the bacterial biofilms were not susceptible to treatment of GaPcs with only 1–2 log reduction of the biofilm The bacterial biofilm E faecalis was effectively inactivated only with MB The water-soluble octa-methylpyridyloxy substituted GaPc2 has a potential value for photodynamic treatment of C albicans biofilms formed on denture acrylic resin

107 citations

Journal ArticleDOI
TL;DR: The bacterial diversity in two uranium waste piles was studied and showed that the uranium wastes were dominated by Acidithiobacillus ferrooxidans and by several Pseudomonas species classified in the γ-subdivision of the Proteobacteria.
Abstract: The bacterial diversity in two uranium waste piles was studied. Total DNA was recovered from a large number of soil samples collected from different sites and depths in the piles using two procedures for direct lysis. Significant differences in the bacterial composition of the samples were revealed by the use of rep-APD, RISA and 16S ARDREA. The 16S rDNA analyses showed that the uranium wastes were dominated by Acidithiobacillus ferrooxidans and by several Pseudomonas species classified in the γ-subdivision of the Proteobacteria. The three kinds of A. ferrooxidans 16S and IGS rDNA specific fragments that were found corresponded to the three phylogenetic groups recognised in this species. This microdiversity probably reflects the genetic adaptation of the uranium waste strains to different concentrations of heavy metals.

107 citations

Journal ArticleDOI
TL;DR: A time-frequency decomposition was applied to the event-related potentials (ERPs) elicited in an auditory oddball condition to assess differences in cognitive informationprocessing and frequency components in delta, theta, and alpha ranges reflected specific aspects of cognitive information processing.

107 citations

Journal ArticleDOI
TL;DR: In this article, two analysis schemes are developed within an off-line version of the land surface scheme ISBA for the initialization of soil water content and temperature in numerical weather prediction models.
Abstract: [1] Two analysis schemes are developed within an off-line version of the land surface scheme ISBA for the initialization of soil water content and temperature in numerical weather prediction models. The first soil analysis is based on optimal interpolation that is currently operational in a number of weather centers. The second soil analysis is an extended Kalman filter (EKF) which will allow the assimilation of satellite observations. First, it is shown, by comparing the Kalman gain of both analysis schemes, that it is possible to assimilate screen level temperature and relative humidity in an off-line system. This is of great interest for future combined assimilations of conventional and satellite data. The reduced computing time in running the land surface scheme outside the atmospheric model makes Kalman filter approaches compatible with operational requirements. The methodology for coupling the land surface data assimilation with the atmospheric analysis system is explained in order to highlight the existing feedbacks between the two systems (in comparison to fully decoupled land data assimilation systems). The linearity of the observation operator Jacobians estimated by finite differences and the relevance of the soil prognostic variables to be initialized are assessed. Finally, the two systems are compared over western Europe for the month of July 2006 by assimilating screen level temperature and relative humidity every 6 h. The EKF has been simplified by keeping the covariance matrix of background errors constant. The two soil analysis schemes behave similarly in response to screen level atmospheric errors. The EKF is superior in identifying situations where the near-surface atmosphere is sensitive to soil perturbations, which leads to better use of observations. Over France, the capability of both systems to moisten the soil when rain events are absent from the forcing is demonstrated.

107 citations


Authors

Showing all 18074 results

NameH-indexPapersCitations
Dimitri Bourilkov134148996884
Eduardo De Moraes Gregores133145492464
Georgi Sultanov132149393318
Plamen Iaydjiev131128587958
Pedro G Mercadante129133186378
Jordan Damgov129119585490
Roumyana Hadjiiska126100373091
Mircho Rodozov12497270519
Cesar Augusto Bernardes12496570889
Viktor Matveev123121273939
Ayda Beddall12081667063
Andrey Marinov11989357183
Mariana Vutova11760656698
Lester Packer11275163116
Patrick Couvreur11167856735
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202345
2022137
20211,321
20201,465
20191,284
20181,248