Limits on the Non-commutativity Scale

A non-vanishing vacuum expectation value for an antisymmetric tensor field leads to the violation of Lorentz invariance, controlled by the dimension (-2) parameter, theta_{mu nu}. We assume that the zeroth order term in theta-expansion represents the Standard Model and study the effects induced by linear terms in theta_{mu nu}. If coupling to theta_{mu nu} is realized in strongly interacting sector of the theory, the clock comparison experiments place the limit on the possible size of this background at the level of 1/\sqrt{theta}>~5X10^{14} GeV. If the interaction with theta_{mu nu} is initially present only in the QED sector, this limit can be relaxed to 10^{11}-10^{12} GeV level. The strength of these limits obviates the inferiority of collider physics with regard to experimental checks of Lorentz invariance. Limits of similar strength are expected to hold in the case of mixed non-commutativity between four-dimensional and extra-dimensional coordinates. We also show that in certain models mixed non-commutativity can be interpreted as 4d CPT-violating background.Comment: 5 pages, Talk presented by Irina Mocioiu at CPT01, Bloomington, Indiana, August 200

Group Management

Working (organizational) group contains one or more individuals that interact regularly in order to achieve a common objective. The organisational group behaviour can react to some factors: using some power categories, using some efficient communication systems, developing the group creativity (by using methods like brainstorming, brainwriting, Delphi technique, writing down in time of the sleep technique, Philips 66 Reunion etc.).Organizational behavior; Communication systems; Workig group.

Maximum a posteriori estimation through simulated annealing for binary asteroid orbit determination

This paper considers a new method for the binary asteroid orbit determination problem. The method is based on the Bayesian approach with a global optimisation algorithm. The orbital parameters to be determined are modelled through an a posteriori distribution made of a priori and likelihood terms. The first term constrains the parameters space and it allows the introduction of available knowledge about the orbit. The second term is based on given observations and it allows us to use and compare different observational error models. Once the a posteriori model is built, the estimator of the orbital parameters is computed using a global optimisation procedure: the simulated annealing algorithm. The maximum a posteriori (MAP) techniques are verified using simulated and real data. The obtained results validate the proposed method. The new approach guarantees independence of the initial parameters estimation and theoretical convergence towards the global optimisation solution. It is particularly useful in these situations, whenever a good initial orbit estimation is difficult to get, whenever observations are not well-sampled, and whenever the statistical behaviour of the observational errors cannot be stated Gaussian like.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Societ

Financial Investment Management: Testing the Market Model on the Romanian Capital Market during the Post Financial Crisis

This article presents an analysis of the decision of investing in the capital market in Romania during 2009-2010, in the context of overcoming the global financial crisis. In the first part of the paper, we have made a brief presentation of the simplified model of market analysis introduced in the specialized literature by William Sharpe, the respective model representing the starting point in our study. The purpose of the present study is to emphasize how the evolutions of the financial securities rates listed on the Bucharest Stock Exchange could be explained based on the evolution of BET Romanian capital market index. Although the study over this phenomenon has begun in the middle of the last century, every day new studies appear that are either coming in addition to the already existing ones or are bringing a new approach regarding the financial theory. The novelty of the present study conducted by us resides in the highlighting of the evolutions of the financial securities rates during July 2009 – December 2010 periods. The second part of the paper presents the results of a study conducted on the Romanian capital market, emphasizing the correlations between the most important securities on the Romanian capital market, as parts of BET index and market index. The aim is to check whether during this period the evolution of the financial securities’ return can be explained more or less by the return of the capital market.financial market model, return of financial securities, security-market correlation.

Low-energy Limits on the Antisymmetric Tensor Field Background on the Brane and on the Non-commutative Scale

A non-vanishing vacuum expectation value for an antisymmetric tensor field leads to the violation of Lorentz invariance on the brane. This violation is controlled by the $\theta_{\mu \nu}$ parameter, which has a dimension of inverse mass squared. We assume that the zeroth order term in theta-expansion represents the Standard Model and study the effects induced by linear terms in theta_{\mu\nu}. Low-energy precision experiments place the limit on the possible size of this background at the level of $1/\sqrt{\theta} > 5 \times 10^{14}$ GeV. This poses certain difficulty for the TeV-range string scale models, in which the antisymmetric field has to acquire a relatively large mass to ensure that $\theta_{\mu \nu}=0$ and avoid cosmological moduli problem.Comment: 9 pages, late

Thermal Rehabilitation Technology and the Nearly Zero-Energy Buildings. Romanian Representative Education Buildings-Case Study

AbstractImproving energy efficiency of the existing buildings is essential, not only for the achievement of the national objectives of energy efficiency in the medium term, but also to meet long-term objectives of the strategy on climate change and the transition to a competitive economy based on low carbon dioxide emission by 2050. Recognizing the diversity of traditions and current practices in the building sector, the climatic conditions and different methodologies of approach across the EU, EPBD [1] does not establish an uniform methodology for implementing nearly zero energy buildings (nZEB), determining each EU Member State to develop its own definition of nZEB. In addition to the new buildings construction, nZEBs and important energy savings in building sector also can be obtained by retrofitting the existing building stock. Until now, the thermal rehabilitation activity was particularly aimed at collective housing sector for which there are appropriate regulations and technologies. Public buildings, in general, are characterized by certain constructive and functional diversity, requiring a specific approach for each case.The aim of the paper is to study the potential of existing education buildings to become nZEBs, by applying current technologies based on improving the general level of thermal protection

Functional electrical stimulation

(Conducător ştiinţific: S. Lozovanu, conf. universitar, V. Ojog, asistent universitar) Catedra Fiziologia Omului şi Biofizică (şef-V. Vovc, prof. universitar)This paper is focused on Functional Electrical Stimulation, a technique that uses electrical stimuli to reestablish the normal activity of organs deprived of nervous control. The concept itself is described along with information about its origin, history, current application and future development. The paper also presents a FES device, developed by the authors, and the experimental results of its testing. Lucrarea dată abordează Stimularea Electrică Funcţională, o tehnică ce utilizează stimuli electrici pentru a restabili activitatea organelor lipsite de control nervos. Este descris conceptul prorpiu-zis, originea lui, datele istorice de referinţă, aplicarea curentă şi viitoare. Totodată, este prezentat proiectul unui dispozitiv SEF realizat de autori şi rezultatele testării sale experimentale