Preheating in the Standard Model with the Higgs-Inflaton coupled to gravity

We study the details of preheating in an inflationary scenario in which the Standard Model Higgs, strongly non-minimally coupled to gravity, plays the role of the inflaton. We find that the Universe does not reheat immediately through perturbative decays, but rather initiate a complex process in which perturbative and non-perturbative effects are mixed. The Higgs condesate starts oscillating around the minimum of its potential, producing W and Z gauge bosons non-perturbatively, due to violation of the so-called adiabaticity condition. However, during each semi-oscillation, the created gauge bosons completely decay (perturbatively) into fermions. This way, the decay of the gauge bosons prevents the development of parametric resonance, since bosons cannot accummulate significantly at the beginning. However, the energy transferred to the decay products of the bosons is not enough to reheat the universe, so after about a hundred oscillations, the resonance effect will finally dominate over the perturbative decays. Around the same time (or slightly earlier), backreaction from the gauge bosons onto the Higgs condensate will also start to be significant. Soon afterwards, the Universe is filled with the remnant condensate of the Higgs and a non-thermal distribution of Standard Model particles which redshift as radiation, while the Higgs continues to oscillate as a pressureless fluid. We compute the distribution of energy among all the species present at backreaction. From there on until thermalization, the evolution of the system is highly non-linear and non-perturbative, and will require a careful study via numerical simulations.Comment: 27 pages, 6 figures; corrected typos, added reference

Educational strategies for the acquisition of professional knowledge by youth basketball coaches

The purpose of this study was to identify the educational means that coaches of school-aged children utilize to acquire their professional knowledge. Youth basketball coaches (n=118) with a heterogeneous education coming from different educational means participated in the study. Of them, 81.7% were previously basketball players. As a measurement instrument, a modified version of the scale by Feu (2006) was utilized to determine the coach's professional knowledge. The new scale had 21 items distributed in seven dimensions that corresponded to three theoretical factors. The items were answered with a 5-point Likert scale. The statistical analysis consisted of an exploratory factor analysis with varimax rotation and self-values >1 in order to determine the latent structure of the relationships between the scale's items. Previously, the Kaiser-Meyer-Olkin index and Bartlett's sphere test were analyzed. The reliability of the scale and the sub-scales was studied through the Cronbach's Alpha coefficient. The means, standard deviations, and correlations between item and scale as well as item and sub-scale were analyzed. The exploratory factor analysis, after the elimination of five items, and the Cronbach's Alpha coefficients demonstrated that the scale and sub-scales had some adequate psychometric properties (α>.70). All the items obtained item and sub-scale correlations greater than .40. Formal education was the factor that had the greatest acceptance among the coaches (M=21.71±4.63) followed by acquired experiences as a player (M=16.70±5.64), and then the acquired experiences and innovations as a coach (M=13.45±2.97). The scale that was utilized has adequate validity and reliability to determine how the coach constructs his/her professional knowledge

Hydrogen/functionalized benzoquinone for a high-performance regenerative fuel cell as a potential large-scale energy storage platform

The redox flow battery (RFB) is a suitable option for electricity storage due to its high energy efficiency, scalability and relative safety. However, the limited metallic resources for redox materials and the high cost in systems such as the all-vanadium RFB are major challenges for wider application. Organics may be sourced more abundantly and have lower prices than metal based redox couples. In this work a regenerative fuel cell involving relatively inexpensive organic redox couples is demonstrated. The electrochemical properties of 1,2-dihydrobenzoquinone-3,5-disulfonic acid (BQDS) are characterised by cyclic voltammetry and linear-sweep voltammetry under hydrodynamic conditions. A regenerative fuel cell using 0.65 M BQDS in 1 M H2SO4 as positive electrolyte and gaseous hydrogen (1 bar) as negative redox-material results in an open circuit cell voltage of 0.86 V, a power density of 122 mW/cm2, and an energy density of 10.90 Wh L-1 without considering the volume occupied by the hydrogen. Very promising performance with an energy efficiency >60% at 100 mA cm-2 for 200 cycles is reported. New organic redox species resistant to side reactions could facilitate the use of this new system in practical applications. The use of hydrogen may also contribute to reduced side reactions of the organic redox associated with degradation in the presence of oxygen

Higgs-Dilaton cosmology: Are there extra relativistic species?

Recent analyses of cosmological data suggest the presence of an extra relativistic component beyond the Standard Model content. The Higgs-Dilaton cosmological model predicts the existence of a massless particle -the dilaton- associated with the spontaneous symmetry breaking of scale invariance and undetectable by any accelerator experiment. Its ultrarelativistic character makes it a suitable candidate for contributing to the effective number of light degrees of freedom in the Universe. In this Letter we analyze the dilaton production at the (p)reheating stage right after inflation and conclude that no extra relativistic degrees of freedom beyond those already present in the Standard Model are expected within the simplest Higgs-Dilaton scenario. The elusive dilaton remains thus essentially undetectable by any particle physics experiment or cosmological observation.Comment: 7 pages, 1 figure, corrected typos; added reference

Perioperative use of levosimendan in patients undergoing cardiac surgery: systematic review and meta-analysis

Introducción: Los pacientes llevados a cirugía cardiaca tienen riesgo de desarrollar síndrome de bajo gasto cardiaco posoper- atorio (SBGC). Estudios previos han encontrado una menor mortalidad con levosimendán respecto a placebo u otros inotrópicos; sin embargo, tres experimentos clínicos no encon- traron beneficio frente a este desenlace. Objetivo: Evaluar la evidencia del levosimendán sobre la mortalidad y los desenlaces secundarios en pacientes sometidos a cirugía cardiaca, y determinar las fuentes de heterogeneidad. Métodos: Mediante una revisión sistemática y metaanálisis de los experimentos clínicos que evaluaron la eficacia del levosi- mendán en los pacientes llevados a cirugía cardiaca, se evaluó la eficacia en la mortalidad y en otros desenlaces, como lesión renal y SBGC, utilizando los modelos de efectos fijos y aleatorios. Resultados: De 47 estudios identificados, fueron seleccionados 14 (n = 2752). Respecto al desenlace de mortalidad y el uso de levosimendán solo se encontró una disminución en los estudios de baja calidad (OR 0.30; IC 95%, 0.18–0.51), mientras que para los de alta calidad no hubo efecto protector (OR 0.99; IC 95%, 0.70–1.40) con un I2 = 0%. La calidad de los estudios y la fracción de eyección fueron las principales fuentes de heterogeneidad. Conclusión: el uso del levosimendán en los pacientes llevados a cirugía cardiovascular no tiene efectos sobre la mortalidad a 30 días en los estudios de alta calidad. Hubo efecto protector sobre la falla renal postoperatoria con necesidad de diálisis.Tabla de contenido 1. RESUMEN ESTRUCTURADO .................................................................................. 4 2. IDENTIFICACIÓN Y FORMULACIÓN DEL PROBLEMA................................... 4 3. OBJETIVOS ................................................................................................................ 6 3.1. Objetivo general .................................................................................................... 6 3.2 Objetivos específicos............................................................................................... 6 4. METODOLOGÍA ........................................................................................................ 6 4.1 Selección de los estudios......................................................................................... 6 4.2 Criterios para incluir los estudios en esta revisión................................................ 6 4.3 Extracción de la información................................................................................. 7 4.4 Análisis estadístico.................................................................................................. 7 5. ASPECTOS ÉTICOS................................................................................................... 7 6. RESULTADOS ............................................................................................................ 7 6.1 Hallazgos generales y evaluación de la calidad de los estudios............................. 7 6.2 Mortalidad a 30 días............................................................................................... 8 6.3 Desenlaces secundarios .......................................................................................... 9 6.4 Sesgo de publicación............................................................................................... 9 7. DISCUSION ................................................................................................................. 9 8. CONCLUSION .......................................................................................................... 12 9. REFERENCIAS......................................................................................................... 12 10. TABLAS ................................................................................................................... 18 Tabla 1: Características de los estudios que incluyeron los desenlaces de mortalidad a 30 días, lesión renal aguda postoperatoria con necesidad de diálisis y fibrilación auricular postoperatoria............................................................................................ 18 11. Títulos de las figuras ................................................................................................ 19 Figura 1. Flujograma identificación y selección de los estudios. .............................. 20 Figura 2. Evaluación del riesgo de sesgo de los estudios incluidos en el metaanálisis. En rojo: alto riesgo, en verde: bajo riesgo, y casilla en blanco: no claro. ................ 21 Figura 3. Efecto del tratamiento con levosimendán vs. terapia estándar en la mortalidad a 30 días en pacientes sometidos a cirugía cardiaca. ............................. 22 Figura 4. Efecto sobre desenlaces secundarios del levosimendán vs. terapia estándar ...................................................................................................................... 23 Figura 5. Gráfico de embudo para mortalidad a 30 días.......................................... 24 12. ANEXOS .................................................................................................................. 25 3 Anexo No 1 ................................................................................................................. 25 Anexo 2. Efecto del tratamiento con levosimendán vs. terapia estándar en el desarrollo de síndrome de bajo gasto cardiaco postoperatorio................................ 27Introduction: Patients undergoing cardiac surgery frequently develop low cardiac output syndrome (LCOS). Multiple inter- ventions including levosimendan have been used in the prevention and treatment of LCOS. Preliminary studies reported lower mortality respect to placebo or other inotropes, however, recently, 3 clinical trials found no benefit against this outcome. Objective: Our objective was to evaluate the evidence of levosimendan on mortality and secondary outcomes in patients undergoing cardiac surgery, and to determine the sources of heterogeneity. Methods: We conducted a systematic review and meta- analysis of the clinical trials that evaluated the efficacy of levosimendan in patients undergoing cardiac surgery. We obtained the odds ratio (OR) of mortality and other outcomes such as kidney injury with dialysis requirement and LCOS, using fixed and random effects models. The risk of bias was assessed and the sources of heterogeneity were explored. Results: Of 47 studies identified, 14 studies were selected (n=2752). Regarding the mortality outcome and use of levosi- mendan, only a decrease was found in the studies of low quality (OR 0,30; CI 95%, 0,18 to 0,51). While high-quality studies, there was no protective effect (OR 0.99, 95% CI 0.70–1.40) with an I2 = 0%. The quality of the studies and ejection fraction were the main sources of heterogeneity. Conclusion: In high-quality studies, the use of levosimendan in patients undergoing cardiovascular surgery has no effect on 30-day mortality. There was a protective effect on postoperative renal failure with dialysis.Especializació

Uterine contractile efficiency indexes for labor prediction: a bivariate approach from multichannel electrohysterographic records

[EN] Labor prediction is one of the most challenging goals in obstetrics, mainly due to the poor understanding of the factors responsible for the onset of labor. The electrohysterogram (EHG) is the recording of the myoelectrical activity of myometrial cells and has been shown to provide relevant information on the electrophysiological state of the uterus. This information could be used to obtain more accurate labor predictions than those of the currently used techniques, such as the Bishop score, tocography or biochemical markers. Indeed, a number of efforts have already been made to predict labor by this method, separately characterizing the intensity, the coupling degree of the EHG signals and myometrial cell excitability, these being the cornerstones on which contraction efficiency is built. Although EHG characterization can distinguish between different obstetric situations, the reported results have not been shown to provide a practical tool for the clinical detection of true labor. The aim of this work was thus to define and calculate indexes from multichannel EHG recordings related to all the phenomena involved in the efficiency of uterine myoelectrical activity (intensity, excitability and synchronization) and to combine them to form global efficiency indexes (GEI) able to predict delivery in less than 7/14 days. Four EHG synchronization indexes were assessed: linear correlation, the imaginary part of the coherence, phase synchronization and permutation cross mutual information. The results show that even though the synchronization and excitability efficiency indexes can detect increasing trends as labor approaches, they cannot predict labor in less than 7/14 days. However, intensity seems to be the main factor that contributes to myometrial efficiency and is able to predict labor in less than 7/14 days. All the GEls present increasing monotonic trends as pregnancy advances and are able to identify (p < 0.05) patients who will deliver in less than 7/14 days better than single channel and single phenomenon parameters. The GEI based on the permutation cross mutual information shows especially promising results. A simplified EHG recording protocol is proposed here for clinical practice, capable of predicting deliveries in less than 7/14 days, consisting of 4 electrodes vertically aligned with the median line of the uterus. (C) 2018 Elsevier Ltd. All rights reserved.The authors are grateful to Zhenhu Liang, of the Yanshan University, who provided essential information for computing the PLV and NPCMI synchronization indexes. This work was supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (DPI2015-68397-R, MINECO/FEDER).Mas-Cabo, J.; Ye Lin, Y.; Garcia-Casado, J.; Alberola Rubio, J.; Perales Marín, AJ.; Prats-Boluda, G. (2018). Uterine contractile efficiency indexes for labor prediction: a bivariate approach from multichannel electrohysterographic records. Biomedical Signal Processing and Control. 46:238-248. https://doi.org/10.1016/j.bspc.2018.07.018S2382484

Design and Assessment of a Robust and Generalizable ANN-Based Classifier for the Prediction of Premature Birth by means of Multichannel Electrohysterographic Records

[EN] Preterm labor is one of the major causes of neonatal deaths and also the cause of significant health and development impairments in those who survive. However, there are still no reliable and accurate tools for preterm labor prediction in clinical settings. Electrohysterography (EHG) has been proven to provide relevant information on the labor time horizon. Many studies focused on predicting preterm labor by using temporal, spectral, and nonlinear parameters extracted from single EHG recordings. However, multichannel analysis, which includes information from the whole uterus and about coupling between the recording areas, may provide better results. The cross validation method is often used to design classifiers and evaluate their performance. However, when the validation dataset is used to tune the classifier hyperparameters, the performance metrics of this dataset may not properly assess its generalization capacity. In this work, we developed and compared different classifiers, based on artificial neural networks, for predicting preterm labor using EHG features from single and multichannel recordings. A set of temporal, spectral, nonlinear, and synchronization parameters computed from EHG recordings was used as the input features. All the classifiers were evaluated on independent test datasets, which were never ¿seen¿ by the models, to determine their generalization capacity. Classifiers¿ performance was also evaluated when obstetrical data were included. The experimental results show that the classifier performance metrics were significantly lower in the test dataset (AUC range 76-91%) than in the train and validation sets (AUC range 90-99%). The multichannel classifiers outperformed the single-channel classifiers, especially when information was combined into mean efficiency indexes and included coupling information between channels. Including obstetrical data slightly improved the classifier metrics and reached an AUC of for the test dataset. These results show promise for the transfer of the EHG technique to preterm labor prediction in clinical practice.This work was supported by the Spanish Ministry of Economy and Competitiveness, the European Regional Development Fund (DPI2015-68397-R, MINECO/FEDER, and RTI2018-094449-A-I00-AR); Generalitat Valenciana (AICO/2019/220); and the VLC/Campus (UPV-FE-2018-B03).Mas-Cabo, J.; Prats-Boluda, G.; Garcia-Casado, J.; Alberola Rubio, J.; Perales Marín, AJ.; Ye Lin, Y. (2019). Design and Assessment of a Robust and Generalizable ANN-Based Classifier for the Prediction of Premature Birth by means of Multichannel Electrohysterographic Records. Journal of Sensors. 2019:1-13. https://doi.org/10.1155/2019/5373810S1132019Goldenberg, R. L., Culhane, J. F., Iams, J. D., & Romero, R. (2008). Epidemiology and causes of preterm birth. 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BJOG: An International Journal of Obstetrics & Gynaecology, 112, 103-108. doi:10.1111/j.1471-0528.2005.00596.xDevedeux, D., Marque, C., Mansour, S., Germain, G., & Duchêne, J. (1993). Uterine electromyography: A critical review. American Journal of Obstetrics and Gynecology, 169(6), 1636-1653. doi:10.1016/0002-9378(93)90456-sChkeir, A., Fleury, M.-J., Karlsson, B., Hassan, M., & Marque, C. (2013). Patterns of electrical activity synchronization in the pregnant rat uterus. BioMedicine, 3(3), 140-144. doi:10.1016/j.biomed.2013.04.007Fuchs, A.-R., Fuchs, F., Husslein, P., & Soloff, M. S. (1984). Oxytocin receptors in the human uterus during pregnancy and parturition. American Journal of Obstetrics and Gynecology, 150(6), 734-741. doi:10.1016/0002-9378(84)90677-xTezuka, N., Ali, M., Chwalisz, K., & Garfield, R. E. (1995). Changes in transcripts encoding calcium channel subunits of rat myometrium during pregnancy. 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Computers in Biology and Medicine, 85, 33-42. doi:10.1016/j.compbiomed.2017.04.013Fergus, P., Idowu, I., Hussain, A., & Dobbins, C. (2016). Advanced artificial neural network classification for detecting preterm births using EHG records. Neurocomputing, 188, 42-49. doi:10.1016/j.neucom.2015.01.107Ren, P., Yao, S., Li, J., Valdes-Sosa, P. A., & Kendrick, K. M. (2015). Improved Prediction of Preterm Delivery Using Empirical Mode Decomposition Analysis of Uterine Electromyography Signals. PLOS ONE, 10(7), e0132116. doi:10.1371/journal.pone.0132116Bradley, A. P. (1997). The use of the area under the ROC curve in the evaluation of machine learning algorithms. Pattern Recognition, 30(7), 1145-1159. doi:10.1016/s0031-3203(96)00142-2Maner, W. L., & Garfield, R. E. (2007). Identification of Human Term and Preterm Labor using Artificial Neural Networks on Uterine Electromyography Data. Annals of Biomedical Engineering, 35(3), 465-473. doi:10.1007/s10439-006-9248-8Smrdel, A., & Jager, F. (2015). Separating sets of term and pre-term uterine EMG records. Physiological Measurement, 36(2), 341-355. doi:10.1088/0967-3334/36/2/341Aditya, S., & Tibarewala, D. N. (2012). Comparing ANN, LDA, QDA, KNN and SVM algorithms in classifying relaxed and stressful mental state from two-channel prefrontal EEG data. International Journal of Artificial Intelligence and Soft Computing, 3(2), 143. doi:10.1504/ijaisc.2012.049010Li, Q., Rajagopalan, C., & Clifford, G. D. (2014). A machine learning approach to multi-level ECG signal quality classification. Computer Methods and Programs in Biomedicine, 117(3), 435-447. doi:10.1016/j.cmpb.2014.09.002Li, Z., Zhang, Q., & Zhao, X. (2017). Performance analysis of K-nearest neighbor, support vector machine, and artificial neural network classifiers for driver drowsiness detection with different road geometries. International Journal of Distributed Sensor Networks, 13(9), 155014771773339. doi:10.1177/1550147717733391Murthy, H. S. N., & Meenakshi, D. M. (2015). ANN, SVM and KNN Classifiers for Prognosis of Cardiac Ischemia- A Comparison. Bonfring International Journal of Research in Communication Engineering, 5(2), 07-11. doi:10.9756/bijrce.8030Ren, J. (2012). ANN vs. SVM: Which one performs better in classification of MCCs in mammogram imaging. Knowledge-Based Systems, 26, 144-153. doi:10.1016/j.knosys.2011.07.016Maul, H., Maner, W., Olson, G., Saade, G., & Garfield, R. (2004). Non-invasive transabdominal uterine electromyography correlates with the strength of intrauterine pressure and is predictive of labor and delivery. The Journal of Maternal-Fetal & Neonatal Medicine, 15(5), 297-301. doi:10.1080/14767050410001695301Mas-Cabo, J., Prats-Boluda, G., Perales, A., Garcia-Casado, J., Alberola-Rubio, J., & Ye-Lin, Y. (2018). Uterine electromyography for discrimination of labor imminence in women with threatened preterm labor under tocolytic treatment. 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Electrohysterography in the diagnosis of preterm birth: a review

This is an author-created, un-copyedited versíon of an article published in Physiological Measurement. IOP Publishing Ltd is not responsíble for any errors or omissíons in this versíon of the manuscript or any versíon derived from it. The Versíon of Record is available online at http://doi.org/10.1088/1361-6579/aaad56.[EN] Preterm birth (PTB) is one of the most common and serious complications in pregnancy. About 15 million preterm neonates are born every year, with ratios of 10-15% of total births. In industrialized countries, preterm delivery is responsible for 70% of mortality and 75% of morbidity in the neonatal period. Diagnostic means for its timely risk assessment are lacking and the underlying physiological mechanisms are unclear. Surface recording of the uterine myoelectrical activity (electrohysterogram, EHG) has emerged as a better uterine dynamics monitoring technique than traditional surface pressure recordings and provides information on the condition of uterine muscle in different obstetrical scenarios with emphasis on predicting preterm deliveries. Objective: A comprehensive review of the literature was performed on studies related to the use of the electrohysterogram in the PTB context. Approach: This review presents and discusses the results according to the different types of parameter (temporal and spectral, non-linear and bivariate) used for EHG characterization. Main results: Electrohysterogram analysis reveals that the uterine electrophysiological changes that precede spontaneous preterm labor are associated with contractions of more intensity, higher frequency content, faster and more organized propagated activity and stronger coupling of different uterine areas. Temporal, spectral, non-linear and bivariate EHG analyses therefore provide useful and complementary information. Classificatory techniques of different types and varying complexity have been developed to diagnose PTB. The information derived from these different types of EHG parameters, either individually or in combination, is able to provide more accurate predictions of PTB than current clinical methods. However, in order to extend EHG to clinical applications, the recording set-up should be simplified, be less intrusive and more robust-and signal analysis should be automated without requiring much supervision and yield physiologically interpretable results. Significance: This review provides a general background to PTB and describes how EHG can be used to better understand its underlying physiological mechanisms and improve its prediction. The findings will help future research workers to decide the most appropriate EHG features to be used in their analyses and facilitate future clinical EHG applications in order to improve PTB prediction.This work was supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund under grant DPI2015-68397-R.Garcia-Casado, J.; Ye Lin, Y.; Prats-Boluda, G.; Mas-Cabo, J.; Alberola Rubio, J.; Perales Marin, AJ. (2018). Electrohysterography in the diagnosis of preterm birth: a review. Physiological Measurement. 39(2). https://doi.org/10.1088/1361-6579/aaad56S39