Pseudoscalar susceptibilities and quark condensates: chiral restoration and lattice screening masses

We derive the formal Ward identities relating pseudoscalar susceptibilities and quark condensates in three-flavor QCD, including consistently the 77-n' sector and the U-A(1) anomaly. These identities are verified in the low-energy realization provided by ChPT, both in the standard SU(3) framework for the octet case and combining the use of the SU(3) framework and the large-Nc expansion of QCD to account properly for the nonet sector and anomalous contributions. The analysis is performed including finite temperature corrections as well as the calculation of U(3) quark condensates and all pseudoscalar susceptibilities, which together with the full set of Ward identities, are new results of this work. Finally, the Ward identities are used to derive scaling relations for pseudoscalar masses which explain the behavior with temperature of lattice screening masses near chiral symmetry restoration.

Search for ultrahigh energy neutrinos in highly inclined events at the Pierre Auger Observatory

The Surface Detector of the Pierre Auger Observatory is sensitive to neutrinos of all flavors above 0.1 EeV. These interact through charged and neutral currents in the atmosphere giving rise to extensive air showers. When interacting deeply in the atmosphere at nearly horizontal incidence, neutrinos can be distinguished from regular hadronic cosmic rays by the broad time structure of their shower signals in the water-Cherenkov detectors. In this paper we present for the first time an analysis based on down-going neutrinos. We describe the search procedure, the possible sources of background, the method to compute the exposure and the associated systematic uncertainties. No candidate neutrinos have been found in data collected from 1 January 2004 to 31 May 2010. Assuming an E-2 differential energy spectrum the limit on the single-flavor neutrino is E(2)dN/dE < 1.74 x 10(-7)GeVcm(-2)s(-1)sr(-1) at 90% C.L. in the energy range 1 x 10(17) eV < E < 1 x 10(20)eV.

Grado de satisfacción de los pacientes hospitalizados con las dietas basales y terapéuticas en centros sanitarios públicos

La satisfacción de las necesidades y expectativas de los pacientes se considera un indicador fundamental de la calidad de la asistencia proporcionada, entendida como una medida de eficacia, confort, pertinencia y control del funcionamiento del sistema sanitario (Donabedian, 1966; Monteagudo et al., 2003; Feldman et al., 2007). Los hospitales españoles están enfocados en la mejora de los cuidados y atención al paciente ingresado; por ello, la alimentación que el hospital presta está reconocida como un indicador importante de la satisfacción de los pacientes. La Alimentación Hospitalaria tiene como objetivo ayudar al personal sanitario a que el paciente se encuentre bien lo antes posible. Para lograr esto, es necesario proporcionar alimentos de buena calidad que hayan sido preparados y cocinados cuidadosamente para retener al máximo el valor nutritivo y presentados al paciente de forma apetitosa (Herrera et al., 2004). Es problemático definir la calidad de los alimentos porque depende de la evaluación del consumidor. A pesar de ello, se ha demostrado que las percepciones de un alimento están afectadas por muchos factores individuales que incluyen el sabor, olor, información del etiquetado, actitudes y recuerdos de experiencias anteriores (Imran, 1999). Las características sensoriales como aspecto, flavor, textura y temperatura se ha visto que son también importantes para los pacientes hospitalarios cuando juzgan la calidad de la comida (Clark, 1998). Textura y flavor tienen un efecto profundo sobre la percepción y la aceptabilidad; sin embargo, el papel de la textura es muy dependiente del producto de que se trate. Adjetivos sobre sus atributos como empapado, acuoso, grumoso, pegajoso, baboso, desmoronado y duro que proporcionan una pérdida de control en la boca no suelen normalmente gustar (Cardello, 1996b). La importancia relativa de un atributo es dependiente de un alimento particular. Las comidas de los pacientes son una parte integral del tratamiento hospitalario y el consumo de una dieta equilibrada es crucial para ayudar a su recuperación (Stratton et al., 2006). En los servicios de alimentación de los hospitales se sirven millones de comidas a diario (solamente en España, donde ese estima que existen unos 1000 hospitales, podemos esperar que el número de pensiones completas cada día ronde las 300.000) y el número atendido en un establecimiento puede variar de 20 a 2.000 personas...

Unpolarized transverse momentum dependent parton distribution and fragmentation functions at next-to-next-to-leading order

The transverse momentum dependent parton distribution/fragmentation functions (TMDs) are essential in the factorization of a number of processes like Drell-Yan scattering, vector boson production, semi-inclusive deep inelastic scattering, etc. We provide a comprehensive study of unpolarized TMDs at next-to-next-to-leading order, which includes an explicit calculation of these TMDs and an extraction of their matching coefficients onto their integrated analogues, for all flavor combinations. The obtained matching coefficients are important for any kind of phenomenology involving TMDs. In the present study each individual TMD is calculated without any reference to a specific process. We recover the known results for parton distribution functions and provide new results for the fragmentation functions. The results for the gluon transverse momentum dependent fragmentation functions are presented for the first time at one and two loops. We also discuss the structure of singularities of TMD operators and TMD matrix elements, crossing relations between TMD parton distribution functions and TMD fragmentation functions, and renormalization group equations. In addition, we consider the behavior of the matching coefficients at threshold and make a conjecture on their structure to all orders in perturbation theory.