A Simple Model Inducing QCD

A simple lattice model inducing a gauge theory is considered. The model describes an interaction of a gauge field to an $N\times N$ complex matrix scalar field transforming as a field in the fundamental representation. In contrast to the Kazakov-Migdal model the model contains only the linear interaction between scalar and gauge lattice fields. This model does not suffer from extra local U(1) symmetries. In an approximation of a translation invariant master field the large N limit of the model is investigated. At large N the gauge fields can be integrated out yielding an effective theory describing an interaction of eigenvalues of the master field. The reduced model exhibits phase transitions at the points $\beta_{\bar {cr}}$ and $\beta _{\underline{cr}}$ and the region $(\beta_{\bar{cr}}, \beta_{\underline{cr}})$ separates the strong and weak regions of the model. To study the behaviour of the model at large $N$ in more systematic way the quenched momentum prescription with constraints for treating the large N limit of gauge theories is used. With the help of the technique of orthogonal polynomials nonlinear equations describing the large N limit of the reduced model {\it with quenching} are presented.Comment: LaTex, 10 page

Scaling Violations in Yang-Mills Theories and Strings in AdS_5

String solitons in AdS_5 contain information of N=4 SUSY Yang-Mills theories on the boundary. Recent proposals for rotating string solitons reproduce the spectrum for anomalous dimensions of Wilson operators for the boundary theory. There are possible extensions of this duality for lower supersymmetric and even for non-supesymmetric Yang-Mills theories. We explicitly demonstrate that the supersymmetric anomalous dimensions of Wilson operators in N=0,1 Yang-Mills theories behave, for large spin J, at the two-loop level in perturbation theory, like log J. We compile the analytic one- and two-loop results for the N=0 case which is known in the literature, as well as for the N=1 case which seems to be missing.Comment: 16 pages, Appendix included in chapter. Version to appear in Nucl.Phys.

Large N QCD -- Continuum reduction

Numerical evidence combined with Eguchi-Kawai reduction indicate that there are no finite volumes effects in the large N limit of QCD as long as the linear extent of the four-torus is bigger than a critical size. This is referred to as continuum reduction. Since fermions in the fundamental representation are naturally quenched in the large N limit, as long as we only have a finite number of flavors, continuum reduction provides us with the exciting possibility to numerically solve large N QCD using chiral fermions and present day computers.Comment: 7 pages, 11 figures, uses espcrc2.sty file, contribution to the LHP2003 workshop held in Cairns, Australi

Actividad física: algo más que gasto energético

Tradicionalmente, se ha considerado el balance energético como la diferencia entre consumo y gasto calórico, asociando resultados positivos a un incremento del índice de masa corporal, que puede conducir hacia sobrepeso u obesidad en casos extremos. En la actualidad, se conocen diversos factores genéticos, metabólicos y ambientales (regulación del apetito, intensidad del ejercicio, sedentarismo), que afectan al balance energético y están induciendo hacia una pandemia de enfermedades crónicas, como la obesidad. El avance del conocimiento científico viene indicando que el ejercicio físico planificado que cumpla con las recomendaciones de actividad física, hace aumentar el nivel de condición física, reduce el sedentarismo y provoca una disminución del índice de masa corporal con un descenso asociado del porcentaje de masa grasa, factores que inducen sobre el bienestar físico, psicológico y socio-emocional

Observation-Based Modeling for Testing and Verifying Highly Dependable Systems – A Practitioner’s Approach

Model-based testing (MBT) can reduce the cost of making test cases for critical applications significantly. Depending on the formality of the models, they can also be used for verification. Once the models are available model-based test case generation and verification can be seen as "push-button solutions." However, making the models is often perceived by practitioners as being extremely difficult, error prone, and overall daunting. This paper outlines an approach for generating models out of observations gathered while a system is operating. After refining the models with moderate effort, they can be used for verification and test case generation. The approach is illustrated with a concrete system from the safety and security domain

Numerical Studies of the Double Scaling Limit in Large N Reduced Model

We study the two-dimensional Eguchi-Kawai model as a toy model of the IIB matrix model, which has been recently proposed as a nonperturbative definition of the type IIB superstring theory. While the planar limit of the model is known to reproduce the two-dimensional Yang-Mills theory, we find through Monte Carlo simulation that the model allows a different large $N$ limit, which can be considered as the double scaling limit in matrix models.Comment: LATTICE98(surfaces), 3 pages, 2 eps-figures; typos correcte

Lattice Superstring and Noncommutative Geometry

Recent developments in superstring theory and noncommutative geometry are deeply related to the idea of Eguchi-Kawai reduction in large N gauge theories which dates back to early 80s. After a general review on this subject including revived interests in solving planar QCD, we present some results in the superstring matrix model suggesting the dynamical generation of 4d space-time due to the collapse of the eigenvalue distribution. We then discuss interesting dynamical properties of field theories in noncommutative geometry, which have been revealed by Monte Carlo simulations of twisted reduced models. We conclude with a comment on the recent proposal for a lattice construction of supersymmetric gauge theories based on reduced models.Comment: 14 pages, 12 figures, Lattice2003(plenary

Metabolic risk score indexes validation in overweight healthy people

The constellation of adverse cardiovascular disease (CVD) and metabolic risk factors, including elevated abdominal obesity, blood pressure (BP), glucose, and triglycerides (TG) and lowered high-density lipoprotein-cholesterol (HDL-C), has been termed the metabolic syndrome (MetSyn) [1]. A number of different definitions have been developed by the World Health Organization (WHO) [2], the National Cholesterol Education Program Adult Treatment Panel III (ATP III) [3], the European Group for the Study of Insulin Resistance (EGIR) [4] and, most recently, the International Diabetes Federation (IDF) [5]. Since there is no universal definition of the Metabolic Syndrome, several authors have derived different risk scores to represent the clustering of its components [6-11]