A new measurement of zinc metallicity in a DLA at z=3.35

We present chemical abundance measurements in the z_abs=3.35045 Damped Lyman-alpha (DLA) system observed in the UVES spectrum of the BAL quasar BR 1117-1329. We measure a neutral hydrogen column density N(HI)=6.9+/-1.7*10^{20} atoms/cm2 and derive mean abundances relative to solar: [Si/H] = -1.26+/-0.13, [Fe/H]=-1.51+/-0.13, [Ni/H]=-1.57+/-0.13, [Cr/H]=-1.36+/-0.13, [Zn/H]=-1.18+/-0.13, [Al/H]>-1.25, [O/H]>-1.25 and [N/H]3. The iron to zinc and chromium to zinc ratios, [Fe/Zn]=-0.33+/-0.05 and [Cr/Zn]=-0.18+/-0.05 demonstrate that the absorber has a low dust content. The nitrogen ratio [N/Si]<-0.98 suggests that the ``secondary'' N production process is taking place in this DLA. Finally, this absorber does not seem to present a convincing alpha-enhancement as shown by the alpha over Fe-peak element ratios: [Si/Fe]=0.25+/-0.06, [Si/Cr]=0.10+/-0.06 and [Si/Zn]=-0.08+/-0.06

Probing the time-variation of the fine-structure constant: Results based on Si IV doublets from a UVES sample

We report a new constraint on the variation of the fine-structure constant based on the analysis of 15 Si IV doublets selected from a ESO-UVES sample. We find \Delta\alpha/\alpha = (+0.15+/-0.43) x 10^-5 over a redshift range of 1.59< z < 2.92 which is consistent with no variation in \alpha. This result represents a factor of three improvement on the constraint on \Delta\alpha/\alpha based on Si IV doublets compared to the published results in the literature. The alkali doublet method used here avoids the implicit assumptions used in the many-multiplet method that chemical and ionization inhomogeneities are negligible and isotopic abundances are close to the terrestrial value.Comment: 12 Pages, 7 figures. Accepted for publication in A&A. In addition to minor corrections an appendix is added in this revised versio

Limits on the time variation of the electromagnetic fine-structure constant in the low energy limit from absorption lines in the spectra of distant quasars

Most of the successful physical theories rely on the constancy of few fundamental quantities (such as the speed of light, $c$, the fine-structure constant, \alpha, the proton to electron mass ratio, \mu, etc), and constraining the possible time variations of these fundamental quantities is an important step toward a complete physical theory. Time variation of \alpha can be accurately probed using absorption lines seen in the spectra of distant quasars. Here, we present the results of a detailed many-multiplet analysis performed on a new sample of Mg II systems observed in high quality quasar spectra obtained using the Very Large Telescope. The weighted mean value of the variation in \alpha derived from our analysis over the redshift range 0.4<z<2.3 is \Delta\alpha/\alpha = (-0.06+/-0.06) x 10^{-5}. The median redshift of our sample (z=1.55) corresponds to a look-back time of 9.7 Gyr in the most favored cosmological model today. This gives a 3\sigma limit, -2.5 x 10^{-16} yr^-1 <(\Delta\alpha/\alpha\Delta t) <+1.2x10^{-16} yr^-1, for the time variation of \alpha, that forms the strongest constraint obtained based on high redshift quasar absorption line systems.Comment: uses revtex, 4 pages 3 figures. Accepted for publication in Physical Review Letter

Probing the variation of the fine-structure constant using QSO absorption lines

Search for the time variation of the fundamental constants is motivated by various unification theories. Here we present constraints on the variation of the fine-structure constant &#945;&#x2261;2/ &#x0127;c) obtained using UVES/VLT samples of QSO absorption systems. We find &lt; &#916;&#945;/&#945; &gt;w = (-0.06 &#177; 0.06) &#215; 10-5 using 23 Mg II systems and the many-multiplet (MM) method. Well selected 15 Si IV systems provide &lt; &#916;&#945;/&#945; &gt;w = (0.15 &#177; 0.43) &#215;10-5. Absence of detectable variation in &#945; is also confirmed by our new very high resolution (R ~ 100,000) observation of zabs = 1.1508 toward HE 0515-4414 using HARPS on the ESO 3.6m telescope

Antisymmetric-Tensor and Electromagnetic effects in an alpha'-non-perturbative Four-Dimensional String Cosmology

Starting from an exact (in the Regge slope alpha') functional method for a bosonic stringy sigma-model, we investigate four-dimensional cosmological string solutions in graviton, dilaton and antisymmetric tensor backgrounds, compatible with world-sheet conformal invariance, and valid beyond perturbative expansions in powers of alpha'. The antisymmetric tensor field, playing the role of an axion in the four-dimensional target space time, leads to spatial anisotropies of the emergent Robertson-Walker expanding Universe, and, upon coupling the system to the electromagnetic field, it results in non-trivial optical activity. Some estimates of the corresponding effects are made and their relevance to current cosmology is briefly discussed

Respuesta hipertensiva al esfuerzo y alteraciones cardiovasculares.

RESUMEN INTRODUCCIÓN: La respuesta exagerada de la tensión arterial al esfuerzo físico en normotensos es objeto de numerosos estudios, por la posible evolución hacia una hipertensión arterial establecida e incluso que puedan tener alteraciones cardíacas precoces. Hay estudios contradictorios al respecto por lo que decidimos realizar un estudio con la siguiente: HIPÓTESIS DE TRABAJO: En personas sanas normotensas, una respuesta exagerada de la tensión arterial sistólica al esfuerzo físico, se relaciona con un aumento de la masa del ventrículo izquierdo, con una disfunción diastólica y con alteraciones del patrón normal de la monitorización de la tensión arterial de 24 h. MATERIAL Y MÉTODOS: Se realizó el estudio transversal con una muestra de 271 personas entre 20 y 65 años de ambos sexos, sanos, normotensos y voluntarios. Estableciéndose 3 grupos: Un grupo de hombres y mujeres entre 20 y 34 años, un grupo de hombres y mujeres entre 35 y 49, y otro grupo de hombres y mujeres entre 50 y 65 años. A todos ellos se les efectuó una encuesta de salud y una entrevista, antecedentes familiares y personales, exploración física completa, toma de la tensión arterial, talla, peso, IMC, (índice de masa corporal), ECG de 12 canales, Ecocardiografía-Doppler, ergometría y monitorización ambulatoria de la tensión arterial de 24 h. Se aplicó un análisis descriptivo de las variables, relaciones entre ellas, tensión arterial sistólica al máximo esfuerzo como variable dependiente y sus correlaciones, comparación de medias, tablas de contingencia y análisis multivariable con regresión lineal múltiple y estratificado por grupos de edad RESULTADOS Y CONCLUSIONES: Se ha observado una respuesta exagerada de la tensión arterial sistólica al esfuerzo en un 23,4 % de los hombres y en un 23,9 % de las mujeres. La respuesta exagerada de la tensión arterial sistólica al esfuerzo se ha relacionado con el aumento de la masa del ventrículo izquierdo, en las mujeres y en los hombres más jóvenes No se ha encontrado relación de la respuesta exagerada de la tensión arterial sistólica al esfuerzo con la disfunción diastólica, ni en los hombres ni en las mujeres Hay relación entre la respuesta exagerada de la tensión arterial sistólica al esfuerzo y la condición de no-dipper diastólico en los hombres pero no en las mujeres. Hay relación entre la respuesta exagerada de la tensión arterial sistólica al esfuerzo y la tensión arterial sistólica de 24 h. en hombres y mujeres Hay relación entre la respuesta exagerada de la tensión arterial sistólica al esfuerzo y la edad, solo en las mujeres, no así en los hombres En cambio en los hombres el IMC sí se relaciona con la respuesta exagerada de la tensión arterial sistólica al esfuerzo, pero no en las mujeres En cuanto a los hábitos tabáquico y el alcohol, solo hay relación en los hombres y con los incrementos absolutos y relativos de la tensión arterial sistólica máxima al esfuerzo. En el caso del alcohol con signo negativo Los antecedentes familiares de diabetes mellitus se asocian con la respuesta hipertensiva durante el esfuerzo de forma más evidente en los hombres y en cambio los antecedentes de hipertensión arterial se asocian mejor en las mujeres, pero tan solo en el incremento relativo de la tensión arterial sistólica al máximo esfuerzo Hay relación entre la respuesta exagerada de la tensión arterial sistólica al esfuerzo y la presión del pulso, en ambos sexos En general se ha visto que es en las mujeres en donde se aprecia una mayor relación entre todas las variables, sugiriendo que el género actúa como una variable modificadora de efecto __________________________________________________________________________________________________Introduction: Exaggerated blood pressure response to physical exercise in normotensive people has been the subject of many studies, as it may develop into hypertension or early cardiac alterations. The exaggerated blood pressure response to exercise was studied in a group of normotensive individuals Material and Methods: A sample of 271 individuals of both sexes, aged between 20 and 65 were studied. They all had a health questionnaire, physical examination, blood pressure recording, 12-lead ECG, Doppler echocardiography, ergometric test and 24 hour ambulatory blood pressure monitoring. Simple analysis of the variables and their relationship, bivariate and multivariate analysis, and multiple linear regression were applied. Results: Exaggerated blood pressure response to exercise was found in 23.4 of the men and 23.9 of the women. In the simple analysis there is a definitive correlation between exaggerated blood pressure response to exercise and the main variables, especially in women, considering the entire sample. In the multivariate analysis a relationship was found with left ventricular mass in the women and younger men. There is no relationship between exaggerate blood pressure response and left ventricular filling, there is only an association of the diastolic non dipper condition in the men. However, there is a correlation with 24 h. systolic arterial pressure, both in men and women. There is also a correlation with pulse pressure for both sexes. With the other variables the results are more uneven. Conclusions: Exaggerate blood pressure response to exercise is related to left ventricle mass only in women and young men. In general a higher correlation between variables can only be observed in women, which suggests that gender behaves as an effect modifying variable

soft robotic manipulation of onions and artichokes in the food industry

This paper presents the development of a robotic solution for a problem of fast manipulation and handling of onions or artichokes in the food industry. The complete solution consists of a parallel robotic manipulatior, a specially designed end-effector based on a customized vacuum suction cup, and a computer vision software developed for pick and place operations. First, the selection and design process of the proposed robotic solution to fit with the initial requeriments is presented, including the customized vacuum suction cup. Then, the kinematic analysis of the parallel manipulator needed to develop the robot control system is reviewed. Moreover, computer vision application is presented inthe paper. Hardware details of the implementation of the building prototype are also shown. Finally, conclusions and future work show the current status of the project

Probing the cosmological variation of the fine-structure constant: Results based on VLT-UVES sample

Development of fundamental physics relies on the constancy of various fundamental quantities such as the fine structure constant. Detecting or constraining the possible time variations of these fundamental physical quantities is an important step toward a complete understanding of basic physics. Here we present the results from a detailed many-multiplet analysis performed using high signal-to-noise ratio, high spectral resolution observations of 23 Mg II systems detected toward 18 QSOs in the redshift range 0.4<z<2.3 obtained using UVES at the VLT. We validate our procedure and define the selection criteria that will avoid possible systematics using detail analysis of simulated data set. We show our Voigt profile fitting code recovers the variation in \alpha very accurately when we use single component systems and multiple component systems that are not heavily blended. Spurious detections are frequently seen when we use heavily blended systems or the systems with very weak lines. Thus we avoided heavily blended systems and the systems with Fe II column density < 2x10^12 cm^-2 in the analysis. All steps involved in the analysis are presented in detail. The weighted mean value of the variation in \alpha obtained from our analysis over the redshift range 0.4<z<2.3 is {\Delta\alpha/\alpha} = (-0.06+/-0.06)x10^-5. The median redshift of our sample is 1.55 the 3\sigma upper limit on the time variation of $\alpha$ is -2.5x10^-16 yr^-1< (\Delta\alpha/\alpha\Delta t) <+1.2x10^-16 yr^-1. To our knowledge this is the strongest constraint from quasar absorption line studies till date.Comment: 23 pages; A&A style, 15 figures, accepte

Auto-adaptative Robot-aided Therapy based in 3D Virtual Tasks controlled by a Supervised and Dynamic Neuro-Fuzzy System

This paper presents an application formed by a classification method based on the architecture of ART neural network (Adaptive Resonance Theory) and the Fuzzy Set Theory to classify physiological reactions in order to automatically and dynamically adapt a robot-assisted rehabilitation therapy to the patient needs, using a three-dimensional task in a virtual reality system. Firstly, the mathematical and structural model of the neuro-fuzzy classification method is described together with the signal and training data acquisition. Then, the virtual designed task with physics behavior and its development procedure are explained. Finally, the general architecture of the experimentation for the auto-adaptive therapy is presented using the classification method with the virtual reality exercise