Superfluid Density in a Highly Underdoped YBCO Superconductor

The superfluid density rho_s(T) = 1/lambda^2(T) has been measured at 2.64 GHz in highly underdoped YBCO, at 37 dopings with T_c between 3 K and 17 K. Within limits set by the transition width Delta T_c ~ 0.4 K, rho_s(T) shows no evidence of critical fluctuations as T goes to T_c, with a mean-field-like transition and no indication of vortex unbinding. Instead, we propose that rho_s displays the behaviour expected for a quantum phase transition in the (3 + 1)-dimensional XY universality class, with rho_s0 ~ (p - p_c), T_c ~ (p - p_c)^1/2 and rho_s(T) ~ (T_c - T)^1 as T goes to T_c.Comment: 4 pages, 5 figures; final version of pape

A stochastic local search algorithm with adaptive acceptance for high-school timetabling

Automating high school timetabling is a challenging task. This problem is a well known hard computational problem which has been of interest to practitioners as well as researchers. High schools need to timetable their regular activities once per year, or even more frequently. The exact solvers might fail to find a solution for a given instance of the problem. A selection hyper-heuristic can be defined as an easy-to-implement, easy-to-maintain and effective 'heuristic to choose heuristics' to solve such computationally hard problems. This paper describes the approach of the team hyper-heuristic search strategies and timetabling (HySST) to high school timetabling which competed in all three rounds of the third international timetabling competition. HySST generated the best new solutions for three given instances in Round 1 and gained the second place in Rounds 2 and 3. It achieved this by using a fairly standard stochastic search method but significantly enhanced by a selection hyper-heuristic with an adaptive acceptance mechanism. © 2014 Springer Science+Business Media New York

Symmetric Teleparallel Gravity: Some exact solutions and spinor couplings

In this paper we elaborate on the symmetric teleparallel gravity (STPG) written in a non-Riemannian spacetime with nonzero nonmetricity, but zero torsion and zero curvature. Firstly we give a prescription for obtaining the nonmetricity from the metric in a peculiar gauge. Then we state that under a novel prescription of parallel transportation of a tangent vector in this non-Riemannian geometry the autoparallel curves coincides with those of the Riemannian spacetimes. Subsequently we represent the symmetric teleparallel theory of gravity by the most general quadratic and parity conserving lagrangian with lagrange multipliers for vanishing torsion and curvature. We show that our lagrangian is equivalent to the Einstein-Hilbert lagrangian for certain values of coupling coefficients. Thus we arrive at calculating the field equations via independent variations. Then we obtain in turn conformal, spherically symmetric static, cosmological and pp-wave solutions exactly. Finally we discuss a minimal coupling of a spin-1/2 field to STPG.Comment: Accepted for publication in the International Journal of Modern Physics

Propiedades antioxidantes de algunas plantas que crecen salvajes en Turquía

In this study, the antioxidant activity of 50% aqueous methanol extracts of 38 plants growing in the Afyonkarahisar province of Turkey were evaluated by various antioxidant assay, including free radical scavenging, hydrogen peroxide (H2O2) scavenging and metal (Fe2+) chelating activities. The methanolic fruit extracts of the Cornus and Morus species (H2O2 and DPPH scavenging activities, Fe2+ chelating activity) and the methanolic leaf extracts of the Mentha species (DPPH scavenging activities) examined in the assay showed the strongest activities. These antioxidant properties depended on the concentration of samples.En este estudio, la actividad antioxidante de extractos metanólicos al 50% en agua de 38 plantas que crecen en la provincia turca de Afyonkarahisar fueron evaluados con algunos ensayos antioxidantes, incluyendo la actividad capta-dora de radicales libres y de peróxido de oxígeno (H2O2) y la actividad quelatante de metales (Fe2+). Los extractos metanólicos de frutas de las especies Cornus y Morus (actividades captadoras de H2O2 y DPPH y actividad quelatante de Fe2+) y los extractos metanólicos de hojas de especies de Mentha (actividad captadora de DPPH) son los que mostraron una actividad mayor. Estas propiedades antioxidantes dependieron de la concentración de la muestra

Perfil fenólico y actividad antioxidante de aceitunas de la variedad turca “Sarıulak” de diferentes procedencias

The phenolic compounds, radical scavenging effect and antioxidant capacity of olive fruits from the “Sarıulak” variety were studied from four different locations: Alanya, Ceyhan, Silifke and Karaman in the Mediterranean region of Turkey. They were collected on three different harvest dates (HDs) and in two consecutive crop years. The levels of most of the phenolic compounds in the fruits of the Alanya location were remarkably high among the values (mg/kg) obtained for all location samples mainly on the first HDs, for instance hydroxytyrosol rose to 3596.4, luteolin rose to 269.5, vanillic acid rose to 159.8 and caffeic acid rose to 62.1. The olive fruits from Alanya, which had the highest average rainfall compared to the other locations, showed the highest phenolic content. The olive fruits from Silifke, which had a dramatic decrease in rainfall between the two crop years, showed a reduction in total phenolic content in the following crop year. The highest oleuropein contents (mg/kg) were detected for the fruit samples grown in Silifke (963.5-2981.8) and for Karaman (835.2-655.6). All of the locations showed similar changes in antioxidant activity pointing to an increase with later HDs. The effect of HD on the phenolic compounds such as 4-hydroxyphenyl acetic acid, caffeic acid, syringic acid and hidroxytyrosol, luteolin, chlorogenic acid and 3,4-dihydroxybenzoic acid were more dependent on the location factor.Se han estudiado los compuestos fenólicos, el efecto captador de radicales y la capacidad antioxidante de aceitunas de la variedad “Sarıulak” procedentes de cuatro localidades diferentes, Alanya, Ceyhan, Silifke y Karaman de la región mediterránea de Turquía, que fueron recogidas en tres diferentes fechas de cosecha (HDs) y en dos años consecutivos de cultivos. Los niveles de la mayoría de estos compuestos fenólicos, expresados en mg/kg , de los frutos procedentes de Alanya fueron los mas altos entre los valores obtenidos de todos los lugares, principalmente en primer HDs, por ejemplo, el hidroxitirosol llega a 3596,4, la luteolina a 269,5, el ácido vanílico a 159,8 y el ácido cafeico a 62,1. Las aceitunas de Alanya, que tenían el mayor promedio de lluvias de las otras localidades, presentó el mayor contenido de fenoles. Las aceitunas de Silifke, que tuvo una dramática disminución de las precipitaciones entre dos años de cultivo, mostraron una reducción en el contenido de fenoles totales en la campaña agrícola siguiente. Los contenidos más alto de oleuropeína fueron detectados en las muestras de frutos cultivadas en Silifke (963,5 a 2.981,8 mg/kg) y Karaman (835.2-655.6 mg/kg). Todas las localidades mostraron cambios similares en la actividad antioxidante que apunta a un aumento con HDs. El efecto de HD en los compuestos fenólicos como el 4-hidroxifenil-acético, ácido cafeico, ácido siríngico, hidroxitirosol, luteolina, ácido clorogénico y el ácido 3,4-dihidroxi fueron más dependientes del factor localización

Wavelength Tunability of Ion-bombardment Induced Ripples on Sapphire

A study of ripple formation on sapphire surfaces by 300-2000 eV Ar+ ion bombardment is presented. Surface characterization by in-situ synchrotron grazing incidence small angle x-ray scattering and ex-situ atomic force microscopy is performed in order to study the wavelength of ripples formed on sapphire (0001) surfaces. We find that the wavelength can be varied over a remarkably wide range-nearly two orders of magnitude-by changing the ion incidence angle. Within the linear theory regime, the ion induced viscous flow smoothing mechanism explains the general trends of the ripple wavelength at low temperature and incidence angles larger than 30. In this model, relaxation is confined to a few-nm thick damaged surface layer. The behavior at high temperature suggests relaxation by surface diffusion. However, strong smoothing is inferred from the observed ripple wavelength near normal incidence, which is not consistent with either surface diffusion or viscous flow relaxation.Comment: Revtex4, 19 pages, 10 figures with JPEG forma

CeCoIn5 - a quantum critical superfluid

We have made the first complete measurements of the London penetration depth $\lambda(T)$ of CeCoIn5, a quantum-critical metal where superconductivity arises from a non-Fermi-liquid normal state. Using a novel tunnel diode oscillator designed to avoid spurious contributions to $\lambda(T)$, we have established the existence of intrinsic and anomalous power-law behaviour at low temperature. A systematic analysis raises the possibility that the unusual observations are due to an extension of quantum criticality into the superconducting state.Comment: 5 pages, 3 figure

The Turkish military's march toward Europe

[No abstract available