The method of Gaussian weighted trajectories. V. On the 1GB procedure for polyatomic processes

In recent years, many chemical reactions have been studied by means of the quasi-classical trajectory (QCT) method within the Gaussian binning (GB) procedure. The latter consists in "quantizing" the final vibrational actions in Bohr spirit by putting strong emphasis on the trajectories reaching the products with vibrational actions close to integer values. A major drawback of this procedure is that if N is the number of product vibrational modes, the amount of trajectories necessary to converge the calculations is ~ 10^N larger than with the standard QCT method. Applying it to polyatomic processes is thus problematic. In a recent paper, however, Czako and Bowman propose to quantize the total vibrational energy instead of the vibrational actions [G. Czako and J. M. Bowman, J. Chem. Phys., 131, 244302 (2009)], a procedure called 1GB here. The calculations are then only ~ 10 times more time-consuming than with the standard QCT method, allowing thereby for considerable numerical saving. In this paper, we propose some theoretical arguments supporting the 1GB procedure and check its validity on model test cases as well as the prototype four-atom reaction OH+D_2 -> HOD+D

Competing risk models in early warning systems for in-hospital deterioration: the role of missing data imputation

Early Warning Systems (EWS) are useful and very important tools for evaluating the health deteriorating of hospitalised patients, using vital signs (such as heart rate, temperature, etc.) as the main input, based on electronic health records (EHR) which most of the time result in sparse data sets with high rates of missing data. In this work, we aim to study the effect of different imputation techniques on time-to-event (survival) models. For each case we have patient's sex and age, as well as longitudinal data along the hospitalisation for 7 vital signs (temperature, systolic and diastolic pressure, heart and respiratory rates, oxygen saturation and neurological state). We summarise these longitudinal data with the following central tendency, order and dispersion statistics: maximum, minimum, first observation, last observation, mean, standard deviation, average variance percentage and average derivative, transforming the original variables into a cross-sectional higher dimensional space, that still having missing data problems. Each hospitalisation has two possible final states: clinical deterioration or favourable discharge. Here, we model the time-to-event with competitive risk models taking into account the covariates. In the Galdakao-Usansolo University Hospital (Basque Country, Spain), a total of 19.602 hospitalisations (lengths of stay at least 24 hours) were collected during the year 2019, of which 852 (4.35\%) resulted in deterioration. These data correspond to 55.8\% of males and 44.2\% of females. We are using a set of imputation methods, such as central tendency statistics (mean and mode), Multiple Imputation by Chained Equations (MICE), Non-Linear Principal Components Analysis (NLPCA) and Random Forest. We evaluate the performances of the imputation methods described before, via root mean square error and conclude the pros and cons of using each one in medical practice. Then, we use Fine and Gray's competitive risk models and the cause-specific Cox proportional hazard regression to model the time-to-event as a function of imputed summarised data. Finally, we evaluate these models employing the traditional and time-dependent area under the ROC curve, for horizon times of 24, 48, 72, 96 and 120 hospitalisation hours

Convergencia mediática digital : el uso y consumo de los nuevos medios por mujeres catalanas

El consumo y la dinámica de las pantallas de comunicación han experimentado en el mundo un marcado aumento en los últimos años y los medios de comunicación tradicionales, con sus gramáticas y mercados perfectamente definidos, han evolucionado como consecuencia del protagonismo de Internet. La convergencia mediática reduce la distancia entre el emisor y el receptor, desapareciendo así la unidireccionalidad y desarrollando una comunicación horizontal que deja la pasividad, ya que el receptor adopta una actitud activa. En este artículo se dibuja el consumo de contenidos que realizan las mujeres en Cataluña, y cuál es el soporte utilizado en el marco de la convergencia mediática digital. Se describen los resultados obtenidos a raíz de combinar 6 grupos de discusión con 6 entrevistas en profundidad en dos grupos segmentados de la población en función de la edad y su formación: grupo infantil y juvenil. Se ha dado prioridad a los colectivos infantil y juvenil porque son los que marcan de forma influyente las tendencias a medio plazo, los que se han socializado con una serie de soportes que no existían anteriormente y los que son más polivalentes en el uso de los diversos soportes disponibles en el mercado. La población adulta no ha sido examinada en el estudio porque posee determinadas barreras de entrada, como la falta de competencias técnicas para el uso de los nuevos dispositivos

Competing risk modelling for in-hospital length of stay

In this study, we propose a framework for analysing in-hospital patient data from electronic health records. We transform longitudinal sparse vital signs measurements into cross-sectional data via descriptive statistics, imputing missing values, and evaluating variables strongly associated with time to mutually exclusive events (favourable medical discharge or deterioration). We employ competing risk and random survival forest techniques to predict patients’ length of stay and evaluate models’ performance via Brier score

Reduced graphene oxides as carbocatalysts in acceptorless dehydrogenation of N-heterocycles

The catalytic properties of graphene-derived materials are evaluated in acceptorless dehydrogenation of N-heterocycles. Among them, reduced graphene oxides (rGOs) are active (quantitative yields in 23 h) under mild conditions (130 °C) and act as efficient heterogeneous carbocatalysts. rGO exhibits reusability and stability at least during eight consecutive runs. Mechanistic investigations supported by experimental evidence (i.e., organic molecules as model compounds, purposely addition of metal impurities and selective functional group masking experiments) suggest a preferential contribution of ketone carbonyl groups as active sites for this transformation.

Transformer modelling considering power losses using an inverse Jiles-Atherton approach

Power transformers are devices with non-linear behavior due to the saturation of the ferromagnetic core. When modelling such devices, the saturation effect must be taken into account because it greatly affects their performance and efficiency. In this paper, an electromagnetic model for power transformers is proposed and experimentally validated using an electrical T-model coupled with a reluctance network to model the magnetic part. The electrical circuit and the reluctance network are linked by two B–H approaches. The B–H relationships are modelled by the full hysteresis cycle based on the inverse Jiles-Atherton theory and by the initial magnetization curve. The results obtained with the inverse Jiles-Atherton theory model reproduce the magnetic core behavior with more accuracy than the one based on the initial magnetization curve, especially at low load conditions where saturation plays a more prominent role on the no-load current. The proposed model can be applied to other magnetic devices such as inductors for power electronic applications or electromechanical relays, among others.Peer ReviewedPostprint (published version

Mode excitation by turbulent convection in rotating stars. I. Effect of uniform rotation

We focus on the influence of the Coriolis acceleration on the stochastic excitation of oscillation modes in convective regions of rotating stars. Our aim is to estimate the asymmetry between excitation rates of prograde and retrograde modes. We extend the formalism derived for obtaining stellar $p$- and $g$-mode amplitudes (Samadi & Goupil 2001, Belkacem et al. 2008) to include the effect of the Coriolis acceleration. We then study the special case of uniform rotation for slowly rotating stars by performing a perturbative analysis. This allows us to consider the cases of the Sun and the CoRoT target HD 49933. We find that, in the subsonic regime, the influence of rotation as a direct contribution to mode driving is negligible in front of the Reynolds stress contribution. In slow rotators, the indirect effect of the modification of the eigenfunctions on mode excitation is investigated by performing a perturbative analysis of the excitation rates. It turns out that the excitation of solar $p$ modes is affected by rotation with excitation rates asymmetries between prograde and retrograde modes of the order of several percents. Solar low-order $g$ modes are also affected by uniform rotation and their excitation rates asymmetries are found to reach up to 10 %. The CoRoT target HD 49933 is rotating faster than the Sun ($\Omega / \Omega_\odot \approx 8$) and we show that the resulting excitation rates asymmetry is about 10 % for the excitation rates of $p$ modes. We have then demonstrated that $p$ and $g$ mode excitation rates are modified by uniform rotation through the Coriolis acceleration. Study of the effect of differential rotation is dedicated to a forthcoming paper.Comment: 9 pages, 4 figures, accepted in A&

Metallothioneins of the urochordate Oikopleura dioica have Cys-rich tandem repeats, large size and cadmium-binding preference

The increasing levels of heavy metals derived from human activity are poisoning marine environments, threating zooplankton and ocean food webs. To protect themselves from the harmful effects of heavy metals, living beings have different physiological mechanisms, one of which is based on metallothioneins (MTs), a group of small cysteine-rich proteins that can bind heavy metals counteracting their toxicity. The MT system of urochordate appendicularians, an ecologically relevant component of the zooplankton,remained, however, unknown. In this work, we have characterized the MTs of the appendicularian species Oikopleura dioica, revealing that O. dioica has two MT genes, named OdMT1 and OdMT2, which encode for Cys-rich proteins, the former with 72 amino acids comparable with the small size MTs of other organisms, but the second with 399 amino acids representing the longest MT reported to date for any living being. Sequence analysis revealed that OdMT2 gene arose from a duplication of an ancestral OdMT1 gene followed by up to six tandem duplications of an ancestral repeat unit (RU) in the current OdMT2 gene. Interestingly, each RU contained, in turn, an internal repeat of a 7-Cys subunit (X3CX3CX2CX2CX3-6CX2CXCX), which is repeated up to 12 times in OdMT2. Finally, ICP-AES analyses of heterologously expressed OdMT proteins showed that both MTs were capable to form metalcomplexes, with preference for cadmium ions. Collectively, our results provide the first characterization of the MT system in an appendicularian species as an initial step to understand the zooplankton response to metal toxicity and other environmental stress situations

HII regions in the CALIFA survey: I. Catalog presentation

We present a new catalogue of H II regions based on the integral field spectroscopy (IFS) data of the extended CALIFA and PISCO samples. The selection of H II regions was based on two assumptions: a clumpy structure with high contrast of H α emission and an underlying stellar population comprising young stars. The catalogue provides the spectroscopic information of 26 408 individual regions corresponding to 924 galaxies, including the flux intensities and equivalent widths of 51 emission lines covering the wavelength range between 3745 and 7200 Å. To our knowledge, this is the largest catalogue of spectroscopic properties of H II regions. We explore a new approach to decontaminate the emission lines from diffuse ionized gas contribution. This diffuse gas correction was estimated to correct every emission line within the considered spectral range. With the catalogue of H II regions corrected, new demarcation lines are proposed for the classical diagnostic diagrams. Finally, we study the properties of the underlying stellar populations of the H II regions. It was found that there is a direct relationship between the ionization conditions on the nebulae and the properties of stellar populations besides the physicals condition on the ionized regions.Fil: Espinosa Ponce, Carlos. Universidad Nacional Autónoma de México; MéxicoFil: Sánchez, S. F.. Universidad Nacional Autónoma de México; MéxicoFil: Morisset, C.. Universidad Nacional Autónoma de México; MéxicoFil: Barrera Ballesteros, J. K.. Universidad Nacional Autónoma de México; MéxicoFil: Galbany, Lluís. Universidad de Granada; EspañaFil: García Benito, Rubén. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Lacerda, E. A. D.. Universidad Nacional Autónoma de México; MéxicoFil: Mast, Damian. Archivo del Observatorio Astronomico de Cordoba ; Observatorio Astronomico de Cordoba ; Rectorado ; Universidad Nacional de Cordoba; . Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin