Emergence of Bloch oscillations in one-dimensional systems

Electrons in periodic potentials exhibit oscillatory motion in presence of an electric field. Such oscillations are known as Bloch oscillations. In this article we theoretically investigate the emergence of Bloch oscillations for systems where the electric field is confined to a finite region, like in typical electronic devices. We use a one-dimensional tight-binding model within the single-band approximation to numerically study the dynamics of electrons after a sudden switching-on of the electric field. We find a transition from a regime with direct current to Bloch oscillations when increasing the system size or decreasing the field strength. We propose a pump-probe scheme to observe the oscillations by measuring the accumulated charge as a function of the pulse-length

IT – CAUSE AND RECOVERY TOOL IN THE ECONOMIC CRISIS CONTEXT

The present paper aims to identify some of the weaknesses in the IT area that have contributed to the current financial crisis. At the same time, the crisis impact over the IT&C industry is analysed. Some case studies are introduced: credit risk evaluation software applications with low performance are one of the main causes for the collapse in the loan market, while investments in software applications for virtual campuses have the potential to contribute to the recovery as they reduce costs. Therefore, the IT&C is presented from two opposite perspectives: a factor that contributed to the on-going economic turmoil and an important tool in the recovery process. In the economic recovery plan designed by the European Union, an important place is dedicated to the investments in IT&C networks, in the Research & Development area or in the development of the global commerce as companies can make profit from every opportunity that appears on the market. Under these circumstances, the authors design a set of performance metrics that are meant to quantify the efficiency of software applications. The concluion is that the existence of performant information systems with high quality metrics and user-friendly interfaces undoubtly leads to an improvement in the economic pressure factors that characterize the crisis.economic crisis, IT, virtual campuses, credit risk evaluation applications, metrics

Unmasking the abnormal events in video

We propose a novel framework for abnormal event detection in video that requires no training sequences. Our framework is based on unmasking, a technique previously used for authorship verification in text documents, which we adapt to our task. We iteratively train a binary classifier to distinguish between two consecutive video sequences while removing at each step the most discriminant features. Higher training accuracy rates of the intermediately obtained classifiers represent abnormal events. To the best of our knowledge, this is the first work to apply unmasking for a computer vision task. We compare our method with several state-of-the-art supervised and unsupervised methods on four benchmark data sets. The empirical results indicate that our abnormal event detection framework can achieve state-of-the-art results, while running in real-time at 20 frames per second.Comment: Accepted at the 2017 International Conference on Computer Vision (ICCV 2017

End-stage head and neck cancer: coping mechanism

Coping mechanisms are patients’ means of adapting to stressful situations and involve psychological and physical changes in behavior. Patients adapt to head and neck cancer in a variety of ways. Head and neck cancers are extremely debilitating, especially in advanced stages of the disease or in end-of-life situations. While an oncology team needs to address the needs of all oncology patients, the advanced terminal patients require special attention. Most of these patients do not cope well with their situation and have a tendency to cease social interactions. Pain is the most frequentlyexperienced medical disability in patients having an end-stage illness experience, and thus an important medical endeavor is to afford dignity to the dying patient facingan incurable disease. In such cases, the medical community should never refuse therapy or to assist a dying patient.In some instances, the patient and family may derive benefit from their religious beliefs

MASSCLEANage -- Stellar Cluster Ages from Integrated Colors --

We present the recently updated and expanded MASSCLEANcolors, a database of 70 million Monte Carlo models selected to match the properties (metallicity, ages and masses) of stellar clusters found in the Large Magellanic Cloud (LMC). This database shows the rather extreme and non-Guassian distribution of integrated colors and magnitudes expected with different cluster age and mass and the enormous age degeneracy of integrated colors when mass is unknown. This degeneracy could lead to catastrophic failures in estimating age with standard SSP models, particularly if most of the clusters are of intermediate or low mass, like in the LMC. Utilizing the MASSCLEANcolors database, we have developed MASSCLEANage, a statistical inference package which assigns the most likely age and mass (solved simultaneously) to a cluster based only on its integrated broad-band photometric properties. Finally, we use MASSCLEANage to derive the age and mass of LMC clusters based on integrated photometry alone. First we compare our cluster ages against those obtained for the same seven clusters using more accurate integrated spectroscopy. We find improved agreement with the integrated spectroscopy ages over the original photometric ages. A close examination of our results demonstrate the necessity of solving simultaneously for mass and age to reduce degeneracies in the cluster ages derived via integrated colors. We then selected an additional subset of 30 photometric clusters with previously well constrained ages and independently derive their age using the MASSCLEANage with the same photometry with very good agreement. The MASSCLEANage program is freely available under GNU General Public License.Comment: 17 pages, 11 figures. Accepted for publication in The Astrophysical Journal. Full resolution figures available in journal versio

Age and Mass for 920 LMC Clusters Derived from 100 Million Monte Carlo Simulations

We present new age and mass estimates for 920 stellar clusters in the Large Magellanic Cloud (LMC) based on previously published broad-band photometry and the stellar cluster analysis package, MASSCLEANage. Expressed in the generic fitting formula, d^{2}N/dM dt ~ M^{\alpha} t^{\beta}, the distribution of observed clusters is described by \alpha = -1.5 to -1.6 and \beta = -2.1 to -2.2. For 288 of these clusters, ages have recently been determined based on stellar photometric color-magnitude diagrams, allowing us to gauge the confidence of our ages. The results look very promising, opening up the possibility that this sample of 920 clusters, with reliable and consistent age, mass and photometric measures, might be used to constrain important characteristics about the stellar cluster population in the LMC. We also investigate a traditional age determination method that uses a \chi^2 minimization routine to fit observed cluster colors to standard infinite mass limit simple stellar population models. This reveals serious defects in the derived cluster age distribution using this method. The traditional \chi^2 minimization method, due to the variation of U,B,V,R colors, will always produce an overdensity of younger and older clusters, with an underdensity of clusters in the log(age/yr)=[7.0,7.5] range. Finally, we present a unique simulation aimed at illustrating and constraining the fading limit in observed cluster distributions that includes the complex effects of stochastic variations in the observed properties of stellar clusters.Comment: Accepted for publication in The Astrophysical Journal, 37 pages, 18 figure

Alcohol Withdrawal – Therapeutical Management in Surgical Patients with Upper Intestinal Bleeding

Psychological dependence involves a desire to use a drug to avoid the unpleasant withdrawal syndrome that results from cessation of exposure to it. Alcohol withdrawal syndrome is one of the most feared complications of alcohol addiction and sometimes can be fatal if not treated properly. Withdrawal syndrome is characterized by neurological hyperexcitability, which can lead to severe psychological and neurological symptoms. A survey was conceived in order to monitor the efficiency of several drug associations (Clonidine, Midazolam, IV ethanol), which were administered at the beginning of intensive therapy admission of achohol addicts. By comparing the postoperative evolution parameters and complications incidences for these patients (such as the hospitalization duration in AIT department, the tracheobronchitis incidence, complications as sepsis, pneumonia and cardiac complications), we managed to determine which treatment is the most beneficial for these cases. Benzodiazepines are frequently used for pharmacological therapy of alcohol addicted patients. In our study Midazolam was very efficient, compared to other therapies. When administered for a maximum of 7 days, the inccidence of side effects remains minimal

Dust effects on the derived Sersic indexes of disks and bulges in spiral galaxies

We present a theoretical study that quantifies the effect of dust on the derived Sersic indexes of disks and bulges. The changes in the derived parameters from their intrinsic values (as seen in the absence of dust) were obtained by fitting Sersic distributions on simulated images of disks and bulges produced using radiative transfer calculations and the model of Popescu et al. 2011. We found that dust has the effect of lowering the measured Sersic index in most cases, with stronger effects for disks and bulges seen through more optically thick lines of sight.Comment: 3 pages, 2 figures, to appear in the Proceedings of the IAU Symposium No.284, "The Spectral Energy Distribution of Galaxies", 5-9 sept. 2011, editors Richard J. Tuffs and Cristina C. Popesc