1,300 research outputs found
2-D Niblett-Bostick magnetotelluric inversion
A simple and robust imaging technique for two-dimensional magnetotelluric interpretations has been developed following the well known Niblett-Bostick transformation for one-dimensional profiles. The algorithm processes series and parallel magnetotelluric impedances and their analytical influence functions using a regularized Hopfield artificial neural network. The adaptive, weighted average approximation preserves part of the nonlinearity of the original problem, yet no initial model in the usual sense is required for the recovery of the model; rather, the built-in relationship between model and data automatically and concurrently considers many half spaces whose electrical conductivities vary according to the data. The use of series and parallel impedances, a self-contained pair of invariants of the impedance tensor, avoids the need to decide on best angles of rotation for identifying TE and TM modes. Field data from a given profile can thus be fed directly into the algorithm without much processing. The solutions offered by the regularized Hopfield neural network correspond to spatial averages computed through rectangular windows that can be chosen at will. Applications of the algorithm to simple synthetic models and to the standard COPROD2 data set illustrate the performance of the approximation
Association between bullying and major depressive disorder in a psychiatric consultation
Assess if there is a significant association between being bullied and presenting depressive symptoms. Materials and methods: In the March---October period of the present year, 8---16-year-old children and adolescents that attended psychiatric consultation for the first time in Dr. Eleuterio González Hospital were included in this study. Test Bull-S was used to determine the presence of bullying (Victim subtype); to evaluate depression 2 instruments were used according to age: Children’s Depression Rating Scale-Revised (CDRS-R) for 8---12-year olds and the Birleson Depression Self-Rating Scale (DSRS) for 13---16-year olds. A total of 147 clinical patients were studied (73 women and 74 men). Data were captured in excel and the Statistical Package for the Social Sciences (SPSS) program was used for statistical analysis. Results: A very significant association was found between being bullied and presenting depression (X2 = .289, p = .0004). Conclusions: These data are in agreement with national and international studies, therefore, reinforcing the evidence of such association. This is why we suggest inquiring about bullying in children and adolescents whose chief complaint is depressive symptomatolog
La satisfacción del turista y los aspectos a considerar en la propuesta de un modelo para su medición en destinos de turismo urbano
La necesidad de los destinos turísticos por obtener ventajas competitivas los obliga a entender mejor que nunca el fenómeno de la satisfacción de sus visitantes. Uno de los abordajes del fenómeno es el establecimiento de modelo explicativos a través de variables determinantes. Una revisión de la literatura sobre modelos de satisfacción del turista y satisfacción del turista en destinos urbanos permitió identificar una serie de consideraciones en la propuesta de modelos para identificar factores determinantes de la satisfacción
Asociación entre el trastorno por déficit de atención e hiperactividad y la rinitis alérgica: una revisión
El trastorno por déficit de atención e hiperactividad (TDAH) y la rinitis alérgica (RA) son diagnósticos frecuentes y con impacto en la calidad de vida de niños y adolescentes. Aunque desde hace varias décadas se ha reportado una posible asociación entre ambos trastornos, los resultados han sido inconsistentes. Se realizó una revisión de la literatura en PubMed y en Google Scholar que incluyó artículos de 1991 al 2014. Se encontró que en los últimos años, nuevos estudios han demostrado asociación entre el TDAH y la RA de manera más consistente que lo reportado con anterioridad. En la presente revisión, se describen también posibles mecanismos fisiopatológicos subyacentes e implicaciones terapéuticas de la asociación. Es importante que se realicen más investigaciones sobre la
asociación entre ambos trastornos y se diluciden los mecanismos fisiopatológicos e implicaciones terapéuticas de la misma.
ABSTRACT
Attention-deficit/hyperactivity disorder (ADHD) and allergic rhinitis (AR) are common diagnoses that impact the quality of life of children and adolescents.
Although for several decades a possible association between both disorders has been reported, these results have been inconsistent. We performed a literature
search in PubMed and Google Scholar that includes articles from 1991 to 2014. We found that in recent years, new studies have demonstrated a more consistent
association between ADHD and AR. Possible underlying pathophysiological mechanisms and therapeutic implications of this association are also described.
It is important to continue studying the association between these disorders and dilucidate its physiopathology and therapeutic implications
Colloidal stability of gadolinium-doped ceria powder in aqueous and non-aqueous media
In this work the colloidal behaviour of Ce0.9Gd0.1O2-δ powder in aqueous and non-aqueous media (ethanol) is studied. Commercial powder was characterised by particle size distribution, specific surface area measurements, X-ray diffraction and scanning electron microscopy. Diluted suspensions were characterised by particle size distribution and zeta potential, using dynamic light scattering and laser Doppler velocimetry principles, respectively. The solubility of the powder in water as a function of pH was analysed by inductively coupled plasma atomic emission spectrometry. Colloidal stability was studied as a function of pH, type and concentration of dispersants (polyacrylic-based deflocculant in water and a phosphate ester in ethanol). The time stability of the suspensions was analysed by multiple light scattering. The most stable suspension was obtained with a phosphate ester content of 2.0wt% in ethanol. Finally, preliminary coatings have been obtained by dip coating using concentrated suspensions, which could be accessible to industrial scale so that they can be used as interlayers in solid oxide fuel cells. © 2012 Elsevier Ltd.We would like to thank grants PSE-120000-2008-0040 and MAT2009-14324-C02-01, financed by the Spanish Government (Ministerio de Ciencia e Innovación) and Feder Program of the European Community, and PI/116, financed by the Aragón Government.Peer Reviewe
Kinematics of the ionized-to-neutral interfaces in Monoceros R2
Context. Monoceros R2 (Mon R2), at a distance of 830 pc, is the only
ultra-compact H ii region (UC H ii) where its associated photon-dominated
region (PDR) can be resolved with the Herschel Space Observatory. Aims. Our aim
is to investigate observationally the kinematical patterns in the interface
regions (i.e., the transition from atomic to molecular gas) associated with Mon
R2. Methods. We used the HIFI instrument onboard Herschel to observe the line
profiles of the reactive ions CH+, OH+ and H2O+ toward different positions in
Mon R2. We derive the column density of these molecules and compare them with
gas-phase chemistry models. Results. The reactive ion CH+ is detected both in
emission (at central and red-shifted velocities) and in absorption (at
blue-shifted velocities). OH+ is detected in absorption at both blue- and
red-shifted velocities, with similar column densities. H2O+ is not detected at
any of the positions, down to a rms of 40 mK toward the molecular peak. At this
position, we find that the OH+ absorption originates in a mainly atomic medium,
and therefore is associated with the most exposed layers of the PDR. These
results are consistent with the predictions from photo-chemical models. The
line profiles are consistent with the atomic gas being entrained in the ionized
gas flow along the walls of the cavity of the H ii region. Based on this
evidence, we are able to propose a new geometrical model for this region.
Conclusions. The kinematical patterns of the OH+ and CH+ absorption indicate
the existence of a layer of mainly atomic gas for which we have derived, for
the first time, some physical parameters and its dynamics.Comment: 6 pages, 5 figures. Accepted for publication in A&
Tentative Detection of the Nitrosylium Ion in Space
We report the tentative detection in space of the nitrosylium ion, NO.
The observations were performed towards the cold dense core Barnard 1-b. The
identification of the NO =2--1 line is supported by new laboratory
measurements of NO rotational lines up to the =8--7 transition
(953207.189\,MHz), which leads to an improved set of molecular constants: \,MHz, \,kHz, and \,MHz. The profile of the feature assigned to NO exhibits two
velocity components at 6.5 and 7.5 km s, with column densities of and cm, respectively. New
observations of NO and HNO, also reported here, allow to estimate the following
abundance ratios: (NO)/(NO), and
(HNO)/(NO). This latter value provides important constraints
on the formation and destruction processes of HNO. The chemistry of NO and
other related nitrogen-bearing species is investigated by the means of a
time-dependent gas phase model which includes an updated chemical network
according to recent experimental studies. The predicted abundance for NO
and NO is found to be consistent with the observations. However, that of HNO
relative to NO is too high. No satisfactory chemical paths have been found to
explain the observed low abundance of HNO. HSCN and HNCS are also reported here
with an abundance ratio of . Finally, we have searched for NNO,
NO, HNNO, and NNOH, but only upper limits have been obtained for
their column density, except for the latter for which we report a tentative
3- detection.Comment: To appear in the Astrophysical Journal October 20, 201
Electrochemical performance of Nd1.95NiO4+δ cathode supported microtubular solid oxide fuel cells
Nd1.95NiO4+δ (NNO) cathode supported microtubular cells were fabricated and characterized. This material presents superior oxygen transport properties in comparison with other commonly used cathode materials. The supporting tubes were fabricated by cold isostatic pressing (CIP) using NNO powders and corn starch as pore former. The electrolyte (GDC, gadolinia doped ceria based) was deposited by wet powder spraying (WPS) on top of pre-sintered tubes and then co-sintered. Finally, a NiO/GDC suspension was dip-coated and sintered as the anode. Optimization of the cell fabrication process is shown. Power densities at 750°C of ~40 mWcm-2 at 0.5V were achieved. These results are the first electrochemical measurements reported using NNO cathode-supported microtubular cells. Further developments of the fabrication process are needed for this type of cells in order to compete with the standard microtubular solid oxide fuel cells (SOFC).The authors thank grant MAT2009-14324-C02-01 and MAT2012-30763, financed by the Spanish Government (Ministerio de Ciencia e Innovación) and Feder program of the European Community, for funding the project.Peer Reviewe
Registro actual del jaguar Panthera onca (Carnivora: Felidae) en el Parque Nacional Cumbres de Monterrey, Nuevo León, México
ResumenPresentamos los primeros registros de jaguar Panthera onca (Carnivora: Felidae) para el Parque Nacional Cumbres de Monterrey, Nuevo León, México. Entre los años 2013 a 2015 se colocaron cámaras trampa en los bosques templados del parque. Se obtuvieron 15 fotografías y 7 vídeos de varios individuos de la especie, que evidencian la presencia de una población dentro del parque nacional y que representa la población residente de jaguares más al norte de su área de distribución, por la vertiente del golfo de México. Por esta razón resulta necesario fortalecer acciones de protección ambiental para asegurar la conservación de esta población como: promover el pago de servicios ambientales, implementar el pago del seguro ganadero, capacitar a comités de vigilancia comunitarios y atender las denuncias sobre conflictos por depredación de ganado doméstico en esta área.AbstractWe present the first records of jaguar (Panthera onca) in Cumbres de Monterrey National Park, Nuevo León, Mexico. We placed remote cameras between 2013 and 2015 in oak forest habitats of the Park and obtained 15 pictures and 7 videos of 4 different individuals of the species. Our results constitute the first evidence of a resident population of jaguars in this protected area and the northernmost population of the species along the Gulf of Mexico. Strenthenging of conservation measures such as environmental services compensation, livestock compensation programs, conflict management and law enforcement are needed to protect this jaguar population
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