1,929 research outputs found
S wave velocity structure below central Mexico using high-resolution surface wave tomography
Shear wave velocity of the crust below central Mexico is estimated using surface wave dispersion measurements from regional earthquakes recorded on a dense, 500 km long linear seismic network. Vertical components of regional records from 90 well-located earthquakes were used to compute Rayleigh-wave group-velocity dispersion curves. A tomographic inversion, with high resolution in a zone close to the array, obtained for periods between 5 and 50 s reveals significant differences relative to a reference model, especially at larger periods (>30 s). A 2-D S wave velocity model is obtained from the inversion of local dispersion curves that were reconstructed from the tomographic solutions. The results show large differences, especially in the lower crust, among back-arc, volcanic arc, and fore-arc regions; they also show a well-resolved low-velocity zone just below the active part of the Trans Mexican Volcanic Belt (TMVB) suggesting the presence of a mantle wedge. Low densities in the back arc, inferred from the low shear wave velocities, can provide isostatic support for the TMVB
Photocatalytic activity in the in-flow degradation of NO on porous TiO2 –coated glasses from hybrid inorganic–organic thin films prepared by a combined ALD/MLD deposition strategy
A combined ALD/MLD (where ALD and MLD stand for atomic and molecular layer deposition, respectively) deposition strategy using TiCl4, H2 O and HQ (hydroquinone) as precursors has been applied for the preparation of inorganic–organic thin films on soda-lime glasses. The alternate deposition of TiO2 layers, by pulsing TiCl4 /H2 O (ALD), and hybrid layers, using TiCl4 /HQ (MLD), results in the formation of thin films that are precursors for porous TiO2-coatings after removal of the HQ template by annealing. The coated-glassed show good photocatalytic activity in the degradation of NO with up to 15% reduction of NO concentration in three successive photocatalytic cycles of 5 h each. Surface Scanning Electron Microscopy (SEM) images show that the TiO2-coating is composed of large grains that are made up of finer subgrains resulting in a porous structure with an average pore size of 3–4 nm. Transmission Electron Microscopy (TEM) images show two regions, a porous columnar structure on top and a denser region over the glass substrate. Energy Dispersive X-Ray (EDX) analysis, nanocrystal electron diffraction and Raman spectroscopy confirm the presence of the anatase phase, which, together with the porosity of the material, accounts for the observed photocatalytic activity. © 2022 by the authors. Licensee MDPI, Basel, Switzerland
Pleurodema tucumanum: Predation
Herein we report predation of a juvenile Pleurodema tucumanum by the water bug Belostoma discretum. This observation took place during the night of 9 April 2009 in the vicinity of the Rio Claro (32.613°S, 66.139°W), near San Francisco, Ayacucho, San Luis 5570, Argentina, in a large pool enclosed by rocks at the river’s edge. A juvenile P. tucumanum (19.6 mm SVL) was observed floating on the surface of the pool (no deeper than 0.2 m), with a B. discretum (24.8 mm long) attached to its abdomen. The water bug was holding the frog with its forelegs while piercing the frog’s left hindlimb with its proboscis. At regular intervals the water bug swam with apparent difficulty carrying the frog to the bottom of the pool, where it rested for an instant before emerging for air and repeating these actions.Facultad de Ciencias Exacta
Pleurodema tucumanum: Predation
Herein we report predation of a juvenile Pleurodema tucumanum by the water bug Belostoma discretum. This observation took place during the night of 9 April 2009 in the vicinity of the Rio Claro (32.613°S, 66.139°W), near San Francisco, Ayacucho, San Luis 5570, Argentina, in a large pool enclosed by rocks at the river’s edge. A juvenile P. tucumanum (19.6 mm SVL) was observed floating on the surface of the pool (no deeper than 0.2 m), with a B. discretum (24.8 mm long) attached to its abdomen. The water bug was holding the frog with its forelegs while piercing the frog’s left hindlimb with its proboscis. At regular intervals the water bug swam with apparent difficulty carrying the frog to the bottom of the pool, where it rested for an instant before emerging for air and repeating these actions.Facultad de Ciencias Exacta
Hexaclorobenzeno (HCB) en leches esterilizadas españolas
Se ha investigado hexaclurobcnLenu (I!Cil) en 329 mucstms d~ leches esterilizadas procedentes de 49 centrales lecheras de todas las regiones espanolas. Las medias obtenidas han sido las siguientes. C:mtobria, 0,227 ppm (en base grasa), Galic.a, 0,050 ppm; castellano-leonesa. 0,289 ppm; Aragón-Navarra. 0.212 ppm; Centro (Madrid), 0,132 pprn; Catalufta. 0,283 ppm; Levmllc, 0,286 ppm; Extremadura, 0,231 ppm; Andalucía, 0,646 ppm; y Salmes, 0,160 ppm. 1.:1 98,7 por LOO de las muestras conten(an HCB; solamente el 13,06 por ciento de éstas rebasaban Jos límites recomendados por la FAO/OMS, sie11do la región Andaluza la que prensentó niveles más elevados
The dependence of oxygen and nitrogen abundances on stellar mass from the CALIFA survey
We analysed the optical spectra of HII regions extracted from a sample of 350
galaxies of the CALIFA survey. We calculated total O/H abundances and, for the
first time, N/O ratios using the semi-empirical routine HII-CHI-mistry, which,
according to P\'erez-Montero (2014), is consistent with the direct method and
reduces the uncertainty in the O/H derivation using [NII] lines owing to the
dispersion in the O/H-N/O relation. Then we performed linear fittings to the
abundances as a function of the de-projected galactocentric distances. The
analysis of the radial distribution both for O/H and N/O in the non-interacting
galaxies reveals that both average slopes are negative, but a non-negligible
fraction of objects have a flat or even a positive gradient (at least 10\% for
O/H and 4\% for N/O). The slopes normalised to the effective radius appear to
have a slight dependence on the total stellar mass and the morphological type,
as late low-mass objects tend to have flatter slopes. No clear relation is
found, however, to explain the presence of inverted gradients in this sample,
and there is no dependence between the average slopes and the presence of a
bar. The relation between the resulting O/H and N/O linear fittings at the
effective radius is much tighter (correlation coefficient = 0.80) than
between O/H and N/O slopes ( = 0.39) or for O/H and N/O in the
individual \hii\ regions ( = 0.37). These O/H and N/O values at the
effective radius also correlate very tightly (less than 0.03 dex of dispersion)
with total luminosity and stellar mass. The relation with other integrated
properties, such as star formation rate, colour, or morphology, can be
understood only in light of the found relation with mass.Comment: Accepted for publication in A&A. 20 pages, 19 figure
Papel de los equipos de atención primaria en la hospitalización infantil de los niños menores de 2 años
ObjetivoDeterminar si la conformación de los equipos de atención primaria con la realización del programa de salud del niño sano da lugar a una disminución del riesgo de hospitalización en los niños menores de 2 años, respecto al sistema sanitario tradicional de consultorio o ambulatorio.DiseñoEstudio epidemiológico de casos-referencia.Casos40% de los niños hospitalizados menores de 24 meses en plantas de hospitalización pediátricas o neonatal del Hospital Universitario Marqués de Valdecilla.Referencia15% de los recién nacidos vivos en dicho hospital. Recogida de información mediante entrevista personal y consulta de la tarjeta sanitaria.Período de estudioabril de 1995 a mayo de 1996.ResultadosLos niños menores de 2 años controlados habitualmente por un médico perteneciente a un equipo de atención primaria presentan una disminución del riesgo de hospitalización para todos los diagnósticos clínicos de 0,57 (IC del 95%, 0,35–0,93), tras haber ajustado por diferentes factores de confusión como educación materna, clase social, etnia, edad materna, consumo de tabaco materno, lactancia natural al nacimiento, ingreso al nacimiento. Se observó una disminución del riesgo de hospitalización por fiebre sin localización aparente en aquellos niños controlados habitualmente por un médico de equipo (RR ajustado, 0,41; IC del 95%, 0,19–0,90).ConclusiónLas ventajas de la reforma en la asistencia sanitaria en el ámbito pediátrico, con la conformación de los equipos de atención primaria y la realización de las actividades que ello conlleva, se traduce en una disminución del riesgo de hospitalización para aquellos niños menores de 2 años cuyo control habitual es realizado por un pediatra perteneciente a un equipo de atención primaria.ObjectiveTo determine whether the structure of primary care teams on carrying out the healthy child health programme leads to a drop in the risk of admission to hospital of children under two, in comparison with the traditional clinic or out-clinic health system.DesignCase-reference epidemiological study.Cases40% of the children under 24 months admitted to paediatric or neonate floors of the Marqués de Valdecilla University Hospital.Reference15% of the recently born children alive in this hospital. Information was gathered through face-to-face interview and by examining health cards. The study ran from April 1995 to May 1996.ResultsChildren under two monitored habitually by a doctor belonging to a primary care team showed a drop in risk of hospital admission for all clinical diagnoses of 0.57 (95% CI, 0.35–0.93), after adjustment due to various confusion factors such as maternal education, social class, ethnic background, mother's age, mother's tobacco consumption, natural breast-feeding at birth, admission at birth. There was a drop of risk of hospital admission for high temperature without apparent cause in those children monitored habitually by a team doctor (adjusted RR = 0.41; 95% CI, 0.19–0.90).ConclusionsThe advantages of the paediatric health care reform with the structuring of the primary care teams and the accompanying activities performed lead to a drop in the risk of hospital admission of those children under two years old who are habitually monitored by a doctor belonging to a primary care team
Trajectories of Symptom Dimensions in Short-Term Response to Antipsychotic Treatment in Patients with a First Episode of Non-Affective Psychosis
Background Trajectory patterns of positive, disorganized and negative dimension symptoms during antipsychotic treatment in drug-naive patients with first-episode psychosis have yet to be examined by using naturalistic data.
Method This pragmatic clinical trial randomized 161 drug-naive patients with a first episode of psychosis to olanzapine, risperidone or haloperidol. Patients were assessed with the Scale for the Assessment of Negative Symptoms (SANS) and Positive Symptoms (SAPS) at baseline and at the end of weeks 1, 2, 3, 4 and 6 of antipsychotic treatment. Censored normal models of response trajectories were developed with three dimensions of the SAPS-SANS scores (positive, disorganized and negative) in order to identify the different response trajectories. Diagnosis, cannabis use, duration of untreated psychosis (DUP), smoking and antipsychotic class were examined as possible predictive variables.
Results Patients were classified in five groups according to the positive dimension, three groups according to the disorganized dimension and five groups according to the negative dimension. Longer DUPs and cannabis use were associated with higher scores and poorer responses in the positive dimension. Cannabis use was associated with higher scores and poorer responses in the disorganized dimension. Only schizophrenia diagnosis was associated with higher scores and poorer responses in the negative dimension.
Conclusions Our results illustrate the heterogeneity of short-term response to antipsychotics in patients with a first episode of psychosis and highlight markedly different patterns of response in the positive, disorganized and negative dimensions. DUP, cannabis use and diagnosis appeared to have a prognostic value in predicting treatment response with different implications for each dimension
A comprehensive asteroseismic modelling of the high-amplitude delta Scuti star RV Arietis
We present a comprehensive asteroseismic study of the double-mode
high-amplitude delta Scuti star HD 187642 (RV Arietis). The modelling includes
some of the most recent techniques: 1) effects of rotation on both equilibrium
models and adiabatic oscillation spectrum, 2) non-adiabatic study of radial and
non-radial modes, 3) relationship between the fundamental radial mode and the
first overtone in the framework of Petersen diagrams. The analysis reveals that
two of the observed frequencies are very probably identified as the fundamental
and first overtone radial modes. Analysis of the colour index variations,
together with theoretical non-adiabatic calculations, points to models in the
range of [7065,7245] K in effective temperature and of [1190, 1270] Myr in
stellar age. These values were found to be compatible with those obtained using
the three other asteroseismic techniques.Comment: accepted for publication in A&
- …