The SU(2) and SU(3) chiral phase transitions within Chiral Perturbation Theory

The SU(2) and SU(3) chiral phase transitions in a hot gas made of pions, kaons and etas are studied within the framework of Chiral Perturbation Theory. By using the meson meson scattering phase shifts in a second order virial expansion, we are able to describe the temperature dependence of the quark condensates. We have estimated the critical temperatures where the different condensates melt. In particular, the SU(3) formalism yields a lower critical temperature for the non-strange condensates than within SU(2), and also suggests that the strange condensate may melt at a somewhat higher temperature, due to the different strange and non-strange quark masses.Comment: 4 pages, two figures. Final version to appear in Phys Rev D. Complete model independent calculation. Unitarized ChPt only used to check extrapolation at high T. References added and numerical bug correcte

Abandono de terrazas de cultivo: recolonización vegetal y erosión en el sureste peninsular

[Resumen] El paisaje del sureste peninsular ha estado marcado, en los últimos decenios, por los cambios en los aprovechamientos de las laderas subáridas. Frente a concepciones lineales de los procesos erosivos que afectan a estos espacios, la metodología empleada y los resultados obtenidos evidencian la necesidad de abordar este tema con planteamientos puramente geográficos, donde se valora el papel de los factores abióticos y bióticos del medio, sin olvidar que ambos son decisivos en la comprensión y explicación del paisaje desde una visión antropocéntrica.[Abstract] In the last decades the southeast peninsular landscape has been affected by the changes in the used subarid slopes. Opposite to lineal conceptions of erosive processes in these areas, the employed methodology and the obtained resu1ts show the need to research this subject with purely geographic patterns in which the abiotic and biotic factors are valued without forgetting that both are decisives in the understanding and explication of the lanscape from an human perspectiv

Osteosíntesis con tornillos de Kadar en las fracturas de cuello femoral

Se estudian retrospectivamente 30 pacientes con fractura de cuello femoral, tipo I y II de Garden, tratadas con osteosíntesis a compresión mediante tornillos de esponjosa tipo Kadar. La edad media de los pacientes fue de 70±19 años, siendo el accidente casual la etiología de todas ellas. Se valoró la calidad de la reducción y de la fijación mediante criterios radiográficos, siendo la reducción óptima en el 93 % de los pacientes y la fijación en el 50%. Como complicaciones hubo 2 desplazamientos precoces de la fractura. No ha habido ninguna pseudoartrosis ni necrosis avascular. Valorando los resultados con arreglo a los criterios de Merle d'Aubigné, hemos obtenidos un 84% de buenos resultados. Creemos que el factor pronóstico más importante es la reducción anatómica de la fractura.Thirty patients with Garden's type I and II femoral neck fracture treated by Kadar's spongiosa compressive screws were retrospectively studied. The mean age of patients was 70±9 years. In all cases, the etiology was a casual accident. Fracture reduction and positioning of the osteosynthesis were assessed by radiographic criteria. Satisfactory reduction was achieved in 93 percent of the patients, and the osteosynthesis was accurate in 50 per cent. As for complications, there were 2 early fracture redisplacement. There were neither non-union nor avascular necrosis. When evaluating functional results according to Merle d'Aubigné criteria, satisfactory results were found in 84 per cent of patients. In our opinion, the more important pronostic factor is the anatomic reduction of the fracture

Improved Analysis of J/psi Decays into a Vector Meson and Two Pseudoscalars

Recently, the BES collaboration has published an extensive partial wave analysis of experimental data on J/psi -> phi pi+pi-, J/psi -> omega pi+pi-, J/psi -> phi K+K- and J/psi -> omega K+K-. These new results are analyzed here, with full account of detection efficiencies, in the framework of a chiral unitary description with coupled-channel final state interactions between pi-pi and K-bar K pairs. The emission of a dimeson pair is described in terms of the strange and nonstrange scalar form factors of the pion and the kaon, which include the final state interaction and are constrained by unitarity and by matching to the next-to-leading-order chiral expressions. This procedure allows for a calculation of the S-wave component of the dimeson spectrum including the f_0(980) resonance, and for an estimation of the low-energy constants of Chiral Perturbation Theory, in particular the large N_c suppressed constants L_4^r and L_6^r. The decays in question are also sensitive to physics associated with OZI violation in the 0++ channel. It is found that the S-wave contributions to phi pi+pi-, phi K+K- and omega pi+pi- given by the BES partial-wave analysis may be very well fitted up to a dimeson center-of-mass energy of ~1.2 GeV, for a large and positive value of L_4^r and a value of L_6^r compatible with zero. An accurate determination of the amount of OZI violation in the J/psi -> phi pi+pi- decay is achieved, and the S-wave contribution to omega K+K- near threshold is predicted.Comment: 18 pages, 6 figures, title changed, accepted version for PR

A Parametrization for K+→π+π−e+νK^+\to \pi^+\pi^- e^+\nu

We discuss various models and Chiral Perturbation Theory results for the $K_{l4}$ form factors $F$ and $G$. We check in how much a simple parametrization with a few parameters can be used to extract information from experiment.Comment: 19 pages, 14 figure

Thermal rho and sigma mesons from chiral symmetry and unitarity

We study the temperature evolution of the rho and sigma mass and width, using a unitary chiral approach. The one-loop pion-pion scattering amplitude in Chiral Perturbation Theory at finite temperature is unitarized via the Inverse Amplitude Method. Our results predict a clear increase with T of both the rho and sigma widths. The masses decrease slightly for high T, while the rho-pion-pion coupling increases. The rho behavior seems to be favored by experimental results. In the sigma case, it signals chiral symmetry restoration.Comment: 5 pages, 5 figures, revtex. References and brief comments added. Final version to appear in Phys. Rev.

Luxación Traumática de Cadera en el Niño

La luxación traumática de cadera en el niño es una lesión poco frecuente. Los autores presentan un caso de luxación anterior de cadera en un niño de 4 años producida por traumatismo mínimo. La exploración realizada en urgencias mostró impotencia funcional para la deambulación y gran dolor. El seguimiento ha sido de 18 meses tras los cuales el paciente no presenta complicaciones. Exponen su experiencia en el caso y revisión de la bibliografía.Traumatic hip dislocation of the hip is rare in children. The authors report a case of anterior hip dislocation in a 4-year-old boy who received relatively minor trauma. He was unable to walk and was in severe pain when seen in emergency room. He was followed-up for 18 months and no complications have appeared. They report here their experience with one case and review the literature

Lifestyle Influence on the Content of Copper, Zinc and Rubidium in Wild Mushrooms

The concentration of 18 trace elements in several species of fungi (arranged in three groups: ectomycorrhizae, saprobes, and epiphytes) has been determined. The measurements were made using the methodology of X-ray fluorescence. Higher contents of Cu and Rb (with statistical support) have been found in the ectomycorrhizal species. The Zn content reached higher concentrations in the saprophytic species. According to the normality test and the search for outliers, the species Clitocybe maxima and Suillus bellini accumulate large amounts of Cu and Rb, respectively, so that both can be named as “outliers.” The leftwards displacement of the density curves and their nonnormality are attributed to the presence of these two species, which exhibit hyperaccumulation skills for Cu and Rb, respectively. Regarding Zn absorption, no particular species were classified as outlier; therefore it can be assumed that the observed differences between the different groups of fungi are due to differences in their nutritional physiology

Patterns on the numerical duplication by their admissibility degree

We develop the theory of patterns on numerical semigroups in terms of the admissibility degree. We prove that the Arf pattern induces every strongly admissible pattern, and determine all patterns equivalent to the Arf pattern. We study patterns on the numerical duplication $S \Join^d E$ when $d \gg0$. We also provide a definition of patterns on rings

Meson-meson scattering within one loop Chiral Perturbation Theory and its unitarization

We present the complete one-loop calculation of all the two meson scattering amplitudes within the framework of SU(3) Chiral Perturbation Theory, which includes pions, kaons and the eta. In addition, we have unitarized these amplitudes with the coupled channel Inverse Amplitude Method, which ensures simultaneously the good low energy properties of Chiral Perturbation Theory and unitarity. We show how this method provides a remarkable description of meson-meson scattering data up to 1.2 GeV including the scattering lengths and the generation of seven light resonances, which is consistent with previous determination of the chiral parameters. Particular attention is paid to discuss the differences and similarities of this work with previous analysis in the literature.Comment: 20 pages, 5 figures. Comments on sigma, kappa and eta', as well as some references added. Final version to appear in Phys.Rev.