Binding energy of localized biexcitons in quantum wells

A variational calculation of the ground state energy of a biexciton in a GaAs/AlGaAs quantum well is presented. The well width fluctuations leading to trapping of the biexcitons are modeled by a parabolic potential. The results obtained for different well widths are compared with recent experimental data. Good agreement is obtained both for the biexciton binding energy and for the Haynes factor. We find that the structure of a biexciton is similar to the one of the H_2 molecule.Comment: 9 pages, 4 figure

Near-forward Raman selection rules of the phonon-polariton created by alloying in (Zn,Be)Se

The Raman selection rules of the (ZnSe, BeSe) mixed phonon polariton created by alloying in the three mode (1ZnSe, 2BeSe) ZnBeSe system, whose dramatic S like dispersion covers the large frequency gap between the ZnSe and BeSe spectral ranges, is studied in its wave vector dependence by near forward scattering. Both the collapse regime away from the Brillouin zone centre and the reinforcement regime near the Brillouin zone centre are addressed, using appropriate laser lines and Be contents. We find that in both regimes the considered phonon polariton, in fact a transverse mode with mixed mechanical and electrical character, obeys the same nominal Raman selection rules as its purely mechanical variant commonly observed in the backscattering geometry. Besides, marked differences in the phonon polariton Raman lineshapes in the two regimes give a hint about how the phonon polariton electrical field E develops while descending the S like dispersion towards the Brillouin zone centre. In the reinforcement regime E is large, leading to intramode on top of intermode transfers of oscillator strength mediated by E between the two BeSe modes, that both exhibit a fine structure on account of the alloy disorder. In contrast, in the collapse regime E remains weak, as testified by the absence of intramode transfer. The discussion is supported by contour modeling of the multi phonon polariton Raman lineshapes in their wave vector dependence within the linear dielectric approach.Comment: 16 pages, 7 figure

GSK3β inhibition and canonical Wnt signaling in mice hearts after myocardial ischemic damage

Altres ajuts: This work was supported by the Ministerio de Ciencia e Innovación (to LB); the Instituto de Salud Carlos III (to LB and to MBP); the Generalitat of Catalunya-Secretaria d'Universitats i Recerca del Departament d'Economia i Coneixement de la Generalitat (to LB); the Fundacion Investigación Cardiovascular to LB, and the Spanish Society of Cardiology (SEC2015 to MBP).Aims Myocardial infarction induces myocardial injury and tissue damage. During myocardial infarction strong cellular response is initiated to salvage the damaged tissues. This response is associated with the induction of different signaling pathways. Of these, the canonical Wnt signaling is increasingly important for its prosurvival cellular role, making it a good candidate for the search of new molecular targets to develop therapies to prevent heart failure in infarcted patients. Methods Herein we report that GSK3β regulates the canonical Wnt signaling in C57Bl6 mice hearts. GSK3β is a canonical Wnt pathway inhibitor. Using GSK3β inhibitors and inducing myocardial injury (MI) in Lrp5 mice model we show that GSK3β phosphorylation levels regulate downstream canonical Wnt pathway genes in the ischemic heart. In the setting of MI, myocardial damage assessment usually correlates with functional and clinical outcomes. Therefore, we measured myocardial injury size in Wt and Lrp5 mice in the presence and absence of two different GSK3 inhibitors prior to MI. Myocardial injury was independent of GSK3 inhibitor treatments and GSK3β expression levels. Results These studies support a central role for GSK3β in the activation of the canonical Wnt pathway in the Wt heart. Although LRP5 is protective against myocardial injury, GSK3β expression levels do not regulate heart damage

Matrix Models and D-branes in Twistor String Theory

We construct two matrix models from twistor string theory: one by dimensional reduction onto a rational curve and another one by introducing noncommutative coordinates on the fibres of the supertwistor space P^(3|4)->CP^1. We comment on the interpretation of our matrix models in terms of topological D-branes and relate them to a recently proposed string field theory. By extending one of the models, we can carry over all the ingredients of the super ADHM construction to a D-brane configuration in the supertwistor space P^(3|4). Eventually, we present the analogue picture for the (super) Nahm construction.Comment: 1+37 pages, reference added, JHEP style, published versio

Familial tumoral calcinosis in two Chinese patients: a case series

Abstract Introduction Tumoral calcinosis is a rare and benign condition characterized by massive subcutaneous soft tissue deposits of calcium phosphate predominantly around large joints. Case presentation Familial tumoral calcinosis was present in two members of a Han Chinese family, namely, the son and daughter. The 14-year-old son had the first operation on his right sole of the foot at the age of six, and then experienced subsequent surgeries at a lesion in his right sole of the foot and left hip, respectively. The 16-year-old daughter underwent her first operation at the age of six in her left gluteal region, and subsequent surgeries were performed due to recurrence at the same lesion. Pathologic diagnoses of surgical specimens in both of the patients were reported as tumoral calcinosis. The laboratory results showed hyperphosphatemia with normal levels of serum calcium and alkaline phosphatase. Only surgical treatment was performed in both patients with satisfactory prognosis. Conclusion This is the first report of Chinese familial tumoral calcinosis. The etiopathogenisis and treatment are discussed.</p

The Economic Diagnostics of Enterprise Competitiveness in the Transport Services Market

The purpose of the article is to determine the economic diagnostics and development of measures to ensure the competitiveness of the enterprise in the transport market in conditions of variability and uncertainty of the external economic environment. The stages and methods of competitive analysis are analyzed. The relevance of the diagnostics of the enterprise is substantiated. The features of the current state of diagnostic systems at domestic transport enterprises are also determined, including the following: use of simple analytical diagnostic methods; a limited number of indicators that are used by managers as indicators of the state of enterprise; retrospective and current direction of diagnostics; use of accounting and statistical accounting data as information sources; predominance of symptomatic type of diagnostics and the single use of etiological diagnostics; use of diagnostics mainly to prevent a crisis state; lack of a formalized methodology for the implementation of economic diagnostics, taking into account industry specifics. The solution of the main problems of the diagnostic system at enterprises in modern economic conditions is proposed, namely: formation of a system of criteria (indicators) that can characterize the object and adequately reflect its condition, taking into account factors of influence; development of a scale for measuring the values of indicators that allow minimizing the influence of the subjectivity factor in the course of diagnosing; development of a formalized methodology for diagnosing the state of enterprises, taking into account the specifics of their activities and developing a methodology for choosing the best option for measures that facilitate the improvement of the work of all components of the object of stud

A multi-detector array for high energy nuclear e+e- pair spectrosocopy

A multi-detector array has been constructed for the simultaneous measurement of energy- and angular correlation of electron-positron pairs produced in internal pair conversion (IPC) of nuclear transitions up to 18 MeV. The response functions of the individual detectors have been measured with mono-energetic beams of electrons. Experimental results obtained with 1.6 MeV protons on targets containing $^{11}$B and $^{19}$F show clear IPC over a wide angular range. A comparison with GEANT simulations demonstrates that angular correlations of $e^+e^-$ pairs of transitions in the energy range between 6 and 18 MeV can be determined with sufficient resolution and efficiency to search for deviations from IPC due to the creation and subsequent decay into $e^+e^-$ of a hypothetical short-lived neutral boson.Comment: 20 pages, 8 figure

Globally Optimised Energy-Efficient Data Centres

Data centres are part of today\u27s critical information and communication infrastructure, and the majority of business transactions as well as much of our digital life now depend on them. At the same time, data centres are large primary energy consumers, with energy consumed by IT and server room air conditioning equipment and also by general building facilities. In many data centres, IT equipment energy and cooling energy requirements are not always coordinated, so energy consumption is not optimised. Most data centres lack an integrated energy management system that jointly optimises and controls all its energy consuming equipments in order to reduce energy consumption and increase the usage of local renewable energy sources. In this chapter, the authors discuss the challenges of coordinated energy management in data centres and present a novel scalable, integrated energy management system architecture for data centre wide optimisation. A prototype of the system has been implemented, including joint workload and thermal management algorithms. The control algorithms are evaluated in an accurate simulation‐based model of a real data centre. Results show significant energy savings potential, in some cases up to 40%, by integrating workload and thermal management