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Search Results: 1 - 10 of 1313 matches for " Radu Vatasescu "
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Cold molecules formation by shaping with light the short-range interaction between cold atoms: photoassociation with strong laser pulses
M. Vatasescu
Physics , 2009,
Abstract: The paper investigates cold molecules formation in the photoassociation of two cold atoms by a strong laser pulse applied at short interatomic distances, which lead to a molecular dynamics taking place in the light-induced (adiabatic) potentials. A two electronic states model in the cesium dimer is used to analyse the effects of this strong coupling regime and to show specific results: i) acceleration of the ground state population to the inner zone due to a non-impulsive regime of coupling at short and intermediate interatomic distances; ii) formation of cold molecules in strongly bound levels of the ground state, where the population at the end of the pulse is much bigger than the population photoassociated in bound levels of the excited state; iii) the final momentum distribution of the ground state wavepacket keeping the signatures of the maxima in the initial wavefunction continuum. It is shown that the topology of the light-induced potentials plays an important role in dynamics.
Entanglement between electronic and vibrational degrees of freedom in a laser-driven molecular system
Mihaela Vatasescu
Physics , 2014, DOI: 10.1103/PhysRevA.88.063415
Abstract: We investigate the entanglement between electronic and vibrational degrees of freedom produced by a vibronic coupling in a molecular system described in the Born-Oppenheimer approximation. Entanglement in a pure state of the Hilbert space $\cal{H}$$=$$\cal{H}$$_{el}$$\bigotimes$$\cal{H}$$_{vib}$ is quantified using the von Neumann entropy of the reduced density matrix and the reduced linear entropy. Expressions for these entanglement measures are derived for the $2 \times N_v$ and $3 \times N_v$ cases of the bipartite entanglement, where 2 and 3 are the dimensions of the electronic Hilbert space $\cal{H}$$_{el}$, and $N_v$ is the dimension of $\cal{H}$$_{vib}$. We study the entanglement dynamics for two electronic states coupled by a laser pulse (a $2 \times N_v$ case), taking as an example a coupling between the $a^3\Sigma_{u}^{+} (6s,6s)$ and $1_g(6s,6p_{3/2})$ states of the Cs$_2$ molecule. The reduced linear entropy expression obtained for the $3 \times N_v$ case is used to follow the entanglement evolution in a scheme proposed for the control of the vibronic dynamics in a Cs$_2$ cold molecule, implying the $a^3\Sigma_{u}^{+}(6s,6s)$, $0_g^-(6s,6p_{3/2})$, and $0_g^-(6s,5d)$ electronic states, which are coupled by a non-adiabatic radial coupling and a sequence of chirped laser pulses.
Mid-term echocardiographic follow up of left ventricular function with permanent right ventricular pacing in pediatric patients with and without structural heart disease
Tchavdar Shalganov, Dora Paprika, Radu Vatasescu, Attila Kardos, Attila Mihalcz, Laszlo Kornyei, Andras Szatmari, Tamas Szili-Torok
Cardiovascular Ultrasound , 2007, DOI: 10.1186/1476-7120-5-13
Abstract: A group of 99 pediatric patients with previously implanted pacemaker was studied retrospectively. Forty-three patients (21 males) had isolated congenital complete or advanced atrioventricular block. The remaining 56 patients (34 males) had pacing indication in the presence of structural heart disease. Thirty-two of them (21 males) had isolated structural heart disease and the remaining 24 (13 males) had complex congenital heart disease. Patients were followed up for an average of 53 ± 41.4 months with 12-lead electrocardiogram and transthoracic echocardiography. Left ventricular shortening fraction was used as a marker of ventricular function. QRS duration was assessed using leads V5 or II on standard 12-lead electrocardiogram.Left ventricular shortening fraction did not change significantly after pacemaker implantation compared to preimplant values overall and in subgroups. In patients with complex congenital heart malformations shortening fraction decreased significantly during the follow up period. (0.45 ± 0.07 vs 0.35 ± 0.06, p = 0.015). The correlation between the change in left ventricular shortening fraction and the mean increase of paced QRS duration was not significant. Six patients developed dilated cardiomyopathy, which was diagnosed 2 months to 9 years after pacemaker implantation.Chronic right ventricular pacing in pediatric patients with or without structural heart disease does not necessarily result in decline of left ventricular function. In patients with complex congenital heart malformations left ventricular shortening fraction shows significant decrease.Chronic right ventricular (RV) apical pacing alters unfavorably left ventricular (LV) electrical activation, mechanical contraction, cardiac output, myocardial perfusion and histology. Permanent RV pacing may have detrimental effect on LV function and may promote to heart failure in adult patients with LV dysfunction [1-10]. The effect of chronic RV apical pacing on LV performance in pediatric pati
Efficient formation of strongly bound ultracold cesium molecules by photoassociation with tunneling
Mihaela Vatasescu,Claude M. Dion,Olivier Dulieu
Physics , 2006, DOI: 10.1088/0953-4075/39/19/S09
Abstract: We calculate the rates of formation and detection of ultracold Cs_2 molecules obtained from the photoassociation of ultracold atoms through the double-well 0g- (6S1/2 + 6P3/2) state. We concentrate on two features previously observed experimentally and attributed to tunneling between the two wells [Vatasescu et al 2000 Phys. Rev. A 61 044701]. We show that the molecules obtained are in strongly bound levels (v''=5,6) of the metastable a3Sigma_u+ (6S1/2 + 6S1/2) ground electronic state.
Optimizing the photoassociation of cold atoms by use of chirped laser pulses
Eliane Luc-Koenig,Mihaela Vatasescu,Francoise Masnou-Seeuws
Physics , 2004, DOI: 10.1140/epjd/e2004-00161-8
Abstract: Photoassociation of ultracold atoms induced by chirped picosecond pulses is analyzed in a non-perturbative treatment by following the wavepackets dynamics on the ground and excited surfaces. The initial state is described by a Boltzmann distribution of continuum scattering states. The chosen example is photoassociation of cesium atoms at temperature T=54 $\mu K$ from the $a^3 \Sigma_u^+(6s,6s)$ continuum to bound levels in the external well of the $0_g^-(6s+6p_{3/2})$ potential. We study how the modification of the pulse characteristics (carrier frequency, duration, linear chirp rate and intensity) can enhance the number of photoassociated molecules and suggest ways of optimizing the production of stable molecules.
Bizarre Parosteal Osteochondromatous Proliferation of the Skull in a Young Male  [PDF]
Radu Baz, Cosmin Niscoveanu
Open Journal of Radiology (OJRad) , 2013, DOI: 10.4236/ojrad.2013.33022
Abstract:

Bizarre parosteal osteochondromatous proliferation (BPOP), as defined by Nora and colleagues in 1983 (also called Nora lesion), is a rare lesion. About 160 cases of BPOP have been presented in the literature to date. The lesion is an exophytic outgrowth from the cortical surface consisting of bone, cartilage and fibrous tissue. These types of lesions have been reported mostly in the hands and feet. Localization at the level of the skull is extremely rare. We report a case of a young man with multiple Nora’s lesions with atypical localization in the skull and mandible.

ECONOMIC CRISIS AND THE COMPETITIVENESS OF TRANSNATIONAL COMPANIES
Liviu RADU,Carmen RADU
Lex et Scientia , 2012,
Abstract: In crisis situations, the competitiveness of transnational companies becomes a particularly complex concept, due to the fact that said business entities are continuously moving within the context of internationalization and increasing use of global strategies. Given the current economic context, one cannot merely assess the competitiveness level of any given transnational company from a static standpoint, depending on the turnover, sales volume or number of employees of said company, but such assessment needs to be made from a dynamic standpoint, in close connection with the internal and international business environment in which that company carries out its activity.
CAREER OPPORTUNITIES IN A DOWNTURN SOCIETY
Carmen RADU,Liviu RADU
Lex et Scientia , 2011,
Abstract: The world crisis that began in 2008 has negative influences over financial and economicalsocial structures, mainly affecting the young working population. The most affected by the current economical and financial crisis is the youth. Jobs offer for young people seems to have decreased to a significant extent, while they of all categories of job candidates are the most affected precisely due to their lack of experience and to the high costs for training new employees under the current competitive labour market conditions. Data from a study by the National Employment Agency indicate for 2010 that only 6.36% of young unemployed (under the age of 25) found jobs within the first three months. In the same time, the main specializations for which personnel was still being recruited at the end of 2010 were IT, outsourcing, accountancy, engineering, retail and pharmaceuticals, according to recruitment agencies.
MULTINATIONAL CARTELS
Liviu RADU,Carmen RADU
Lex et Scientia , 2009,
Abstract: Improving the functioning of market for the benefit of European consumers and companies remains an essential component of the European project. In 2007, the competition related policy had a significant contribution in the welfare of consumers by approaching the issue of cartels. Although the fight against cartels is becoming increasingly global and an ever larger challenge, the efforts of the European institutions in this fight have begun to take shape. Clemency European policy has proven to be an extremely powerful weapon in encouraging societies to admit that cartels exist. The competition policy fits more and more the other policies of the European Commission. The recent revisal of the Lisbon Strategy as approved by the European Council stipulates the competition norms as part of the areas in which EU can contribute with specific expertise, beneficial for its key partners. This is closely connected to the need of delivering loyal competition and equal conditions worldwide. The present paper represents a study on the positive and negative influences in the activity of cartels.
CAREER OPPORTUNITIES IN A DOWNTURN SOCIETY
CARMEN RADU,LIVIU RADU
Challenges of the Knowledge Society , 2011,
Abstract: The world crisis that began in 2008 has negative influences over financial and economical-social structures, mainly affecting the young working population. The most affected by the current economical and financial crisis is the youth. Jobs offer for young people seems to have decreased to a significant extent, while they of all categories of job candidates are the most affected precisely due to their lack of experience and to the high costs for training new employees under the current competitive labour market conditions. Data from a study by the National Employment Agency indicate for 2010 that only 6.36% of young unemployed (under the age of 25) found jobs within the first three months. In the same time, the main specializations for which personnel was still being recruited at the end of 2010 were IT, outsourcing, accountancy, engineering, retail and pharmaceuticals, according to recruitment agencies.
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