RESUMEN
The structural stability and physical properties of CrVO4 under compression were studied by x-ray diffraction, Raman spectroscopy, optical absorption, resistivity measurements, and ab initio calculations up to 10 GPa. High-pressure x-ray diffraction and Raman measurements show that CrVO4 undergoes a phase transition from the ambient pressure orthorhombic CrVO4-type structure (Cmcm space group, phase III) to the high-pressure monoclinic CrVO4-V phase, which is proposed to be isomorphic to the wolframite structure. Such a phase transition (CrVO4-type â wolframite), driven by pressure, also was previously observed in indium vanadate. The crystal structure of both phases and the pressure dependence in unit-cell parameters, Raman-active modes, resistivity, and electronic band gap, are reported. Vanadium atoms are sixth-fold coordinated in the wolframite phase, which is related to the collapse in the volume at the phase transition. Besides, we also observed drastic changes in the phonon spectrum, a drop of the band-gap, and a sharp decrease of resistivity. All the observed phenomena are explained with the help of first-principles calculations.
RESUMEN
We present an experimental study of the high-pressure, high-temperature behaviour of cerium up to â¼22 GPa and 820 K using angle-dispersive x-ray diffraction and external resistive heating. Studies above 820 K were prevented by chemical reactions between the samples and the diamond anvils of the pressure cells. We unambiguously measure the stability region of the orthorhombic oC4 phase and find it reaches its apex at 7.1 GPa and 650 K. We locate the α-cF4-oC4-tI2 triple point at 6.1 GPa and 640 K, 1 GPa below the location of the apex of the oC4 phase, and 1-2 GPa lower than previously reported. We find the α-cF4 â tI2 phase boundary to have a positive gradient of 280 K (GPa)-1, less steep than the 670 K (GPa)-1 reported previously, and find the oC4 â tI2 phase boundary to lie at higher temperatures than previously found. We also find variations as large as 2-3 GPa in the transition pressures at which the oC4 â tI2 transition takes place at a given temperature, the reasons for which remain unclear. Finally, we find no evidence that the α-cF4 â tI2 is not second order at all temperatures up to 820 K.
RESUMEN
The aim of this study was to monitor the spatio-temporal spread of influenza incidence in Spain during the 2009 pandemic and the following two influenza seasons 2010-2011 and 2011-2012 using a Bayesian Poisson mixed regression model; and implement this model of geographical analysis in the Spanish Influenza Surveillance System to obtain maps of influenza incidence for every week. In the pandemic wave the maps showed influenza activity spreading from west to east. The 2010-2011 influenza epidemic wave plotted a north-west/south-east pattern of spread. During the 2011-2012 season the spread of influenza was geographically heterogeneous. The most important source of variability in the model is the temporal term. The model of spatio-temporal spread of influenza incidence is a supplementary tool of influenza surveillance in Spain.
Asunto(s)
Brotes de Enfermedades , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/epidemiología , Teorema de Bayes , Humanos , Incidencia , Gripe Humana/transmisión , Gripe Humana/virología , Vigilancia de la Población , Agrupamiento Espacio-Temporal , España/epidemiologíaRESUMEN
Familial spinal neurofibromatosis (FSNF) is a rare localized subtype of NF1 which shows neurological symptomatology during adult life. Only a few families have been reported to date. We describe a family in which three members in two generations, mother, son and daughter, were affected. The patients, aged 48, 22 and 18 years, had spinal bilateral neurofibromas affecting all spinal roots. Spinal symptoms were not present in any of the patients. However, the son had generalized nerve sheath tumors that caused important signs of peripheral neuropathy. The daughter also had benign tumors that involved the left optic nerve and chiasm and the left cerebellar hemisphere. The spinal neurofibromas underwent an important growth in size between 20 and 22 years of age. A specific mutation G848R, 2542 G > C in NF1 exon 16 was present in all three patients.
Asunto(s)
Neurofibromatosis 1/genética , Neoplasias del Sistema Nervioso Periférico/genética , Nervios Espinales , Adolescente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neurofibromatosis 1/patología , Linaje , Neoplasias del Sistema Nervioso Periférico/patologíaRESUMEN
Mo-V-Te-Nb metal oxide catalysts prepared by hydrothermal synthesis and heat-treated in N2 at high temperatures (600-700 degrees C) show high activity and selectivity for the oxidative dehydrogenation of ethane to ethene. Yields of ethene of 75% have been obtained at 400 degrees C on the best catalysts.
RESUMEN
Physaloptera brevivaginata has been found parasitising the stomach of two species of bats of the family Vespertilionidae, Myotis myotis and Myotis blythii, in Spain. A comparative study of the prevalences and mean intensities of parasitism by this physalopterid revealed no statistically significant differences between the two hosts. Likewise, no relationship was found between parasite intensity and host body weight. The histopathological study of the stomach lesion revealed destruction of the mucosa, with degeneration of the gastric glands, loss of the muscularis mucosae and focal necrosis at the points where the cephalic extremities of both sexes of this nematode attach to the mucosa. The present paper is the first study of gastric pathology caused by an adult physalopterid in bats.
Asunto(s)
Quirópteros/parasitología , Infecciones por Spirurida/veterinaria , Spiruroidea/crecimiento & desarrollo , Estómago/parasitología , Animales , Peso Corporal , Femenino , Masculino , España/epidemiología , Infecciones por Spirurida/epidemiología , Infecciones por Spirurida/parasitología , Infecciones por Spirurida/patología , Spiruroidea/aislamiento & purificación , Estómago/patologíaRESUMEN
A description is made of a new trichurid species of the subfamily Capillariinae, Aonchotheca moraveci sp. n., parasitizing the stomach of the long-fingered bat, Myotis capaccinii (Bonaparte, 1837), in Spain. The male presents two caudal lateral alae, a membranous caudal bursa supported by two forked expansions, a spicule 405-536 microns long and a non-spiny spicular sheath. The female has a vulvar appendage and the egg-shell surface presents a fine striation, only scarcely appreciable at the polar plugs.