145 research outputs found
Numerical Solutions of Matrix Differential Models using Cubic Matrix Splines II
This paper presents the non-linear generalization of a previous work on
matrix differential models. It focusses on the construction of approximate
solutions of first-order matrix differential equations Y'(x)=f(x,Y(x)) using
matrix-cubic splines. An estimation of the approximation error, an algorithm
for its implementation and illustrative examples for Sylvester and Riccati
matrix differential equations are given.Comment: 14 pages; submitted to Math. Comp. Modellin
Solución en forma cerrada de sistemas acoplados de Riccati en teoría de juegos discretos
En este artículo se propone una solución no iterativa de sistemas acoplados matriciales de Riccati que aparecen en la resolución de teoría de juegos discretos cuando se aplica la estrategia de Nash en bucle abierto. Mediante el uso de transformaciones algebraicas apropiadas el problema. Se transforma en otro desacoplado para el que una solución en forma cerrada es viable.Peer Reviewe
Global Partial Density of States: Statistics and Localization Length in Quasi-one Dimensional disordered systems
We study the distributions functions for global partial density of states
(GPDOS) in quasi-one-dimensional (Q1D) disordered wires as a function of
disorder parameter from metal to insulator. We consider two different models
for disordered Q1D wire: a set of two dimensional potentials with an
arbitrary signs and strengths placed randomly, and a tight-binding Hamiltonian
with several modes and on-site disorder. The Green functions (GF) for two
models were calculated analytically and it was shown that the poles of GF can
be presented as determinant of the rank , where is the number of
scatters. We show that the variances of partial GPDOS in the metal to insulator
crossover regime are crossing. The critical value of disorder where we
have crossover can be used for calculation a localization length in Q1D
systems.Comment: RevTex4 8 .eps figure
Designing Efficient and Sustainable Predictions of Water Quality Indexes at the Regional Scale Using Machine Learning Algorithms
Water quality and scarcity are key topics considered by the Sustainable Development Goals (SDGs), institutions, policymakers and stakeholders to guarantee human safety, but also vital to protect natural ecosystems. However, conventional approaches to deciding the suitability of water for drinking purposes are often costly because multiple characteristics are required, notably in low-income countries. As a result, building right and trustworthy models is mandatory to correctly manage available groundwater resources. In this research, we propose to check multiple classification techniques such as Decision Trees (DT), K-Nearest Neighbors (KNN), Discriminants Analysis (DA), Support Vector Machine (SVM), and Ensemble Trees (ET) to design the best strategy allowing the forecast a Water Quality Index (WQI). To achieve this goal, an extended dataset characterized by water samples collected in a total of twelve municipalities of the Wilaya of Naâma in Algeria was considered. Among them, 151 samples were examined as training samples, and 18 were used to test and confirm the prediction model. Later, data samples were classified based on the WQI into four states: excellent water quality, good water quality, poor water quality, and very poor or unsafe water. The main results revealed that the SVM classifier obtained the highest forecast accuracy, with 95.4% of prediction accuracy when the data are standardized and 88.9% for the accuracy of the test samples. The results confirmed that the use of machine learning models are powerful tools for forecasting drinking water as larger scales to promote the design of efficient and sustainable water quality control and support decision-plans.This work is part of PRFU project N° E04N01CU450120220001. The authors gratefully acknowledge the support of the General Directorate of Scientific Research and Technological Development (DGRSDT) and to Taif University Researchers Supporting Project TURSP 2020/34, Taif University, Taif, Saudi Arabia
Use of canopy coefficients obtained from satellite data to estimate evapotranspiration over high mountain Mediterranean watersheds
This work explores the dynamics of the water consumed by the
vegetation in two Mediterranean watersheds of Sierra Nevada Mountains
(Southern Spain). This region has experienced an increase in the demand of
water in the last years due to the growth of irrigated areas, and a new water
resources plan is required. The evapotranspiration (ET) of irrigated
horticultural crops and natural communities were monitored for the
hydrological years 2013/14 and 2014/15, using an approach based on the
concept of reference evapotranspiration (ETo) and canopy
coefficients derived from the computation of vegetation indices (VIs),
which we will call the VI-ETo approach. A set of Landsat-8 and
MODIS images has been used as remote input data. The results were used for
the spatial analysis of water consumption in terms of the main land cover
types in the area. The annual runoff obtained with a simple surface water
balance, using the ET values estimated by the VI-ETo approach,
was comparable to that obtained by the HBV (Hydrologiska Byrans
Vattenbalansavdelning) model, a precipitation-runoff generation model that
reproduces the observed river discharge at the outlet of the watershed.</p
Modeling Spanish anxiolytic consumption: Economic, demographic and behavioral influences
Anxiolytics (AX) are the psychotropic drugs prescribed for the treatment of anxiety and
insomnia for 2–4 weeks, for longer periods of consumption (>1 month) may lead to
the development of tolerance or addiction. In fact, its prescription was 16% of the total
pharmaceutical expenditure in Spain in 2007. This paper deals with the development of a
mathematical model describing the dynamic of the addiction to AX for the case study of
the Spanish region of Castellón. The reasons believed to cause the development of addicts
to AX are the economic situation, the marriage termination and the social contact. The
simulations performed to forecast the addicts rate for the period 2010–2014 showed an
increase from 6% in 2010 to 14% in 2014 with a fluctuation of about 2% between the
possible economic scenarios. Finally, the analysis of sensitivity of the rate of addicts to the
fluctuation of the social contact parameters was performed, letting us estimate its impact
on the pharmaceutical expenditure.De La Poza, E.; Guadalajara Olmeda, MN.; Jódar Sánchez, LA.; Merello Giménez, P. (2013). Modeling Spanish anxiolytic consumption: Economic, demographic and behavioral influences. Mathematical and Computer Modelling. 57(7):1619-1624. https://doi.org/10.1016/j.mcm.2011.10.020S1619162457
Efficient orthogonal matrix polynomial based method for computing matrix exponential
The matrix exponential plays a fundamental role in the solution of differential systems which appear in different science fields. This paper presents an efficient method for computing matrix exponentials based on Hermite matrix polynomial expansions. Hermite series truncation together with scaling and squaring and the application of floating point arithmetic bounds to the intermediate results provide excellent accuracy results compared with the best acknowledged computational methods. A backward-error analysis of the approximation in exact arithmetic is given. This analysis is used to provide a theoretical estimate for the optimal scaling of matrices. Two algorithms based on this method have been implemented as MATLAB functions. They have been compared with MATLAB functions funm and expm obtaining greater accuracy in the majority of tests. A careful cost comparison analysis with expm is provided showing that the proposed algorithms have lower maximum cost for some matrix norm intervals. Numerical tests show that the application of floating point arithmetic bounds to the intermediate results may reduce considerably computational costs, reaching in numerical tests relative higher average costs than expm of only 4.43% for the final Hermite selected order, and obtaining better accuracy results in the 77.36% of the test matrices. The MATLAB implementation of the best Hermite matrix polynomial based algorithm has been made available online. © 2011 Elsevier Inc. All rights reserved.This work has been supported by the Programa de Apoyo a la Investigacion y el Desarrollo of the Universidad Politecnica de Valencia PAID-05-09-4338, 2009.Sastre, J.; Ibáñez González, JJ.; Defez Candel, E.; Ruiz Martínez, PA. (2011). Efficient orthogonal matrix polynomial based method for computing matrix exponential. Applied Mathematics and Computation. 217(14):6451-6463. https://doi.org/10.1016/j.amc.2011.01.004S645164632171
Group and sex differences in social cognition in bipolar disorder, schizophrenia/schizoaffective disorder and healthy people
Background: Impairment of social cognition is documented in bipolar disorder (BD) and schizophrenia/schizoaffective disorder (SCH). In healthy individuals, women perform better than men in some of its sub-domains. However, in BD and SCH the results are mixed. Our aim was to compare emotion recognition, affective Theory of Mind (ToM) and first- and second-order cognitive ToM in BD, SCH and healthy subjects, and to investigate sex-related differences. Methods: 120 patients (BD = 60, SCH = 60) and 40 healthy subjects were recruited. Emotion recognition was assessed by the Pictures of Facial Affect (POFA) test, affective ToM by the Reading the Mind in the Eyes Test (RMET) and cognitive ToM by several false-belief stories. Group and sex differences were analyzed using parametric (POFA, RMET) and non-parametric (false-belief stories) tests. The impact of age, intelligence quotient (IQ) and clinical variables on patient performance was examined using a series of linear/logistic regressions. Results: Both groups of patients performed worse than healthy subjects on POFA, RMET and second-order false-belief (p < 0.001), but no differences were found between them. Instead, their deficits were related to older age and/or lower IQ (p < 0.01). Subthreshold depression was associated with a 6-fold increased risk of first-order false-belief failure (p < 0.001). Sex differences were only found in healthy subjects, with women outperforming men on POFA and RMET (p ≤ 0.012), but not on first/second-order false-belief. Limitations: The cross-sectional design does not allow for causal inferences. Conclusion: BD and SCH patients had deficits in emotion recognition, affective ToM, and second-order cognitive ToM, but their performance was comparable to each other, highlighting that the differences between them may be subtler than previously thought. First-order cognitive ToM remained intact, but subthreshold depression altered their normal functioning. Our results suggest that the advantage of healthy women in the emotional and affective aspects of social cognition would not be maintained in BD and SCH
Las acequias de careo de Sierra Nevada (sur de España), un sistema de recarga ancestral en acuíferos de alta montaña
En las partes altas de Sierra Nevada (sur de España) se realiza, desde época andalusí (Edad Media), un Sistema Integrado de Gestión del Agua Subterránea, en el que las acequias de careo constituyen un elemento clave. Estos canales excavados en el terreno están diseñados para recargar las aguas procedentes del deshielo, a lo largo de su recorrido y en distintas zonas concretas, donde hay una mayor permeabilidad del terreno. Una vez que el agua se infiltra en las partes altas de los valles, pasa a circular lentamente por los acuíferos superficiales y surge por ríos y manantiales situados a media ladera. En este trabajo se presentan los resultados conseguidos mediante el monitoreo e investigación hidrogeológica de una cuenca de 68 km2 (cuenca del río Bérchules), situada en Sierra Nevada, donde se aplica la técnica de careo. Los resultados conseguidos han permitido comprobar que el careo aplana el hidrograma de los ríos de alta montaña, reduciendo su componente nival y aumentando la subterránea. Además contribuye a mantener el caudal de los manantiales y los ecosistemas asociados a esta descarga. Su uso en otras zonas de alta montaña permitiría disponer de una excelente herramienta de adaptación al cambio climático.Instituto Geológico y Minero de España, EspañaUniversidad Politécnica de Cataluña, EspañaAgencia de Medio Ambiente y Agua de la Junta de Andalucía, EspañaUniversidad Pablo de Olavide, EspañaConsejería de Medio Ambiente y Ordenación del Territorio, Junta de Andalucía, EspañaPeer reviewe
One-step in vitro generation of ETV2-null pig embryos
Each year, tens of thousands of people worldwide die of end-stage organ failure due to the limited availability of organs for use in transplantation. To meet this clinical demand, one of the last frontiers of regenerative medicine is the generation of humanized organs in pigs from pluripotent stem cells (PSCs) via blastocyst complementation. For this, organ-disabled pig models are needed. As endothelial cells (ECs) play a critical role in xenotransplantation rejection in every organ, we aimed to produce hematoendothelial-disabled pig embryos targeting the master transcription factor ETV2 via CRISPR-Cas9-mediated genome modification. In this study, we designed five different guide RNAs (gRNAs) against the DNA-binding domain of the porcine ETV2 gene, which were tested on porcine fibroblasts in vitro. Four out of five guides showed cleavage capacity and, subsequently, these four guides were microinjected individually as ribonucleoprotein complexes (RNPs) into one-cell-stage porcine embryos. Next, we combined the two gRNAs that showed the highest targeting efficiency and microinjected them at higher concentrations. Under these conditions, we significantly improved the rate of biallelic mutation. Hence, here, we describe an efficient one-step method for the generation of hematoendothelial-disabled pig embryos via CRISPR-Cas9 microinjection in zygotes. This model could be used in experimentation related to the in vivo generation of humanized organs
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