26 research outputs found
El sistema caprino extensivo en la sierra norte y este de Jaén, como base del desarrollo sostenible
En los quince municipios de menos de 5000 habitantes, localizados en el Parque Natural de Cazorla, Segura y Las Villas se ha puesto de manifiesto un proceso de despoblación, envejecimiento y empobrecimiento. La desaparición del mundo rural es un indicador de la degradación medioambiental. El presente trabajo pretende valorar técnica y económicamente el sector caprino de este parque natural, así como su nivel de competencia con el bosque mediterráneo. El estudio se centra en una muestra representativa de las explotaciones de caprino autóctono extensivo del parque natural, constituida por 63 rebaños, que representan el 60 p.100 del total de explotaciones La dimensión media de las explotaciones es de 213 cabras, con una UTH dedicada al caprino y dos por granja. El sistema productivo es eminentemente pastoril, de carácter familiar, con razas autóctonas muy adaptadas, pastos comunales y un régimen característico de pacería, denominado costeo y con unos canales de comercialización ineficientes. El ganado caprino (sin contabilizar el ovino y el vacuno) permite facturar por término medio 1.800.000 pta y generar un flujo de caja en torno a las 300.000 pta al año. Los valores de carga (0,78 UO por ha) están en consonancia con la capacidad sustentadora del parque entre 0,31 y 0,92 UO por ha (Gallego et al., 1991) y son inferiores a lo manifestados por Fernández Rebollo (1995). Además de la importancia económica y social del sistema productivo de carácter sustentable, se ha de tener presente que los protagonistas del desarrollo sostenible son los habitantes del medio rural y estos han de participar la adopción de decisiones
Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum
We report a first measurement for ultra-high energy cosmic rays of the
correlation between the depth of shower maximum and the signal in the water
Cherenkov stations of air-showers registered simultaneously by the fluorescence
and the surface detectors of the Pierre Auger Observatory. Such a correlation
measurement is a unique feature of a hybrid air-shower observatory with
sensitivity to both the electromagnetic and muonic components. It allows an
accurate determination of the spread of primary masses in the cosmic-ray flux.
Up till now, constraints on the spread of primary masses have been dominated by
systematic uncertainties. The present correlation measurement is not affected
by systematics in the measurement of the depth of shower maximum or the signal
in the water Cherenkov stations. The analysis relies on general characteristics
of air showers and is thus robust also with respect to uncertainties in
hadronic event generators. The observed correlation in the energy range around
the `ankle' at differs significantly from
expectations for pure primary cosmic-ray compositions. A light composition made
up of proton and helium only is equally inconsistent with observations. The
data are explained well by a mixed composition including nuclei with mass . Scenarios such as the proton dip model, with almost pure compositions, are
thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray
flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report
Numbe
Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory
Atmospheric parameters, such as pressure (P), temperature (T) and density,
affect the development of extensive air showers initiated by energetic cosmic
rays. We have studied the impact of atmospheric variations on extensive air
showers by means of the surface detector of the Pierre Auger Observatory. The
rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find
that the observed behaviour is explained by a model including the effects
associated with the variations of pressure and density. The former affects the
longitudinal development of air showers while the latter influences the Moliere
radius and hence the lateral distribution of the shower particles. The model is
validated with full simulations of extensive air showers using atmospheric
profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle
Physic
The exposure of the hybrid detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays.
It consists of a surface array to measure secondary particles at ground level
and a fluorescence detector to measure the development of air showers in the
atmosphere above the array. The "hybrid" detection mode combines the
information from the two subsystems. We describe the determination of the
hybrid exposure for events observed by the fluorescence telescopes in
coincidence with at least one water-Cherenkov detector of the surface array. A
detailed knowledge of the time dependence of the detection operations is
crucial for an accurate evaluation of the exposure. We discuss the relevance of
monitoring data collected during operations, such as the status of the
fluorescence detector, background light and atmospheric conditions, that are
used in both simulation and reconstruction.Comment: Paper accepted by Astroparticle Physic
The Fluorescence Detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a hybrid detector for ultra-high energy
cosmic rays. It combines a surface array to measure secondary particles at
ground level together with a fluorescence detector to measure the development
of air showers in the atmosphere above the array. The fluorescence detector
comprises 24 large telescopes specialized for measuring the nitrogen
fluorescence caused by charged particles of cosmic ray air showers. In this
paper we describe the components of the fluorescence detector including its
optical system, the design of the camera, the electronics, and the systems for
relative and absolute calibration. We also discuss the operation and the
monitoring of the detector. Finally, we evaluate the detector performance and
precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics
Research Section
Deep-sequencing reveals broad subtype-specific HCV resistance mutations associated with treatment failure
A percentage of hepatitis C virus (HCV)-infected patients fail direct acting antiviral (DAA)-based treatment regimens, often because of drug resistance-associated substitutions (RAS). The aim of this study was to characterize the resistance profile of a large cohort of patients failing DAA-based treatments, and investigate the relationship between HCV subtype and failure, as an aid to optimizing management of these patients. A new, standardized HCV-RAS testing protocol based on deep sequencing was designed and applied to 220 previously subtyped samples from patients failing DAA treatment, collected in 39 Spanish hospitals. The majority had received DAA-based interferon (IFN) a-free regimens; 79% had failed sofosbuvir-containing therapy. Genomic regions encoding the nonstructural protein (NS) 3, NS5A, and NS5B (DAA target regions) were analyzed using subtype-specific primers. Viral subtype distribution was as follows: genotype (G) 1, 62.7%; G3a, 21.4%; G4d, 12.3%; G2, 1.8%; and mixed infections 1.8%. Overall, 88.6% of patients carried at least 1 RAS, and 19% carried RAS at frequencies below 20% in the mutant spectrum. There were no differences in RAS selection between treatments with and without ribavirin. Regardless of the treatment received, each HCV subtype showed specific types of RAS. Of note, no RAS were detected in the target proteins of 18.6% of patients failing treatment, and 30.4% of patients had RAS in proteins that were not targets of the inhibitors they received. HCV patients failing DAA therapy showed a high diversity of RAS. Ribavirin use did not influence the type or number of RAS at failure. The subtype-specific pattern of RAS emergence underscores the importance of accurate HCV subtyping. The frequency of “extra-target” RAS suggests the need for RAS screening in all three DAA target regions
Astrophysical Interpretation Of Pierre Auger Observatory Measurements Of The Uhecr Energy Spectrum And Mass Composition
13
Upper limit on the cosmic-ray photon fraction at EeV energies from the Pierre Auger Observatory
From direct observations of the longitudinal development of ultra-high energy
air showers performed with the Pierre Auger Observatory, upper limits of 3.8%,
2.4%, 3.5% and 11.7% (at 95% c.l.) are obtained on the fraction of cosmic-ray
photons above 2, 3, 5 and 10 EeV (1 EeV = 10^18 eV) respectively. These are the
first experimental limits on ultra-high energy photons at energies below 10
EeV. The results complement previous constraints on top-down models from array
data and they reduce systematic uncertainties in the interpretation of shower
data in terms of primary flux, nuclear composition and proton-air
cross-section.Comment: 20 pages, 7 figures, 2 tables. Minor changes. Accepted by
Astroparticle Physic