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1,497 results on '"Burgos M"'

1. New results on biorthogonal families in cylindrical domains and controllability consequences

Author

Khodja, F. Ammar, Benabdallah, A., González-Burgos, M., Morancey, M., and de Teresa, L.

Subjects
Mathematics - Analysis of PDEs, Mathematics - Functional Analysis, Mathematics - Optimization and Control
Abstract

In this article we consider moment problems equivalent to null controllability of some linear parabolic partial differential equations in space dimension higher than one. For these moment problems, we prove existence of an associated biorthogonal family and estimate its norm. The considered setting requires the space domain to be a cylinder and the evolution operator to be tensorized. Roughly speaking, we assume that the so-called Lebeau-Robbiano spectral inequality holds but only for the eigenvectors of the transverse operator. In the one dimensional tangent variable we assume the solvability of block moment problem as introduced in [Benabdallah, Boyer and Morancey - \textit{Ann. H. Lebesgue.} 3 (2020)]. We apply this abstract construction of biorthogonal families to the characterization of the minimal time for simultaneous null controllability of two heat-like equations in a cylindrical domain. To the best of our knowledge, this result is unattainable with other known techniques.

Published
2024

2. Boundary controllability of a one-dimensional phase-field system with one control force

Author

Burgos, M. González and Sousa-Neto, G.

Subjects
Mathematics - Optimization and Control
Abstract

In this paper, we present some controllability results for linear and nonlinear phase-field systems of Caginalp type considered in a bounded interval of $\mathbb R$ when the scalar control force acts on the temperature equation of the system by means of the Dirichlet condition on one of the endpoints of the interval. In order to prove the linear result we use the moment method providing an estimate of the cost of fast controls. Using this estimate and following the methodology developed in~\cite{tucsnack}, we prove a local exact boundary controllability result to constant trajectories of the nonlinear phase-field system. To the authors' knowledge, this is the first nonlinear boundary controllability result in the framework of non-scalar parabolic systems, framework in which some ``hyperbolic'' behaviors could arise., Comment: arXiv admin note: text overlap with arXiv:2104.00610 by other authors

Published
2024
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3. Quantitative Fattorini-Hautus test and minimal null control time for parabolic problems

Author

Khodja, F. Ammar, Benabdallah, A., González-Burgos, M., and Morancey, M.

Subjects
Mathematics - Optimization and Control, 93C20, 93B05, 93C25
Abstract

This paper investigates the link between the null controllability property for some abstract parabolic problems and an inequality that can be seen as a quantified Fattorini-Hautus test. Depending on the hypotheses made on the abstract setting considered we prove that this inequality either gives the exact minimal null control time or at least gives the qualitative property of existence of such a minimal time. We also prove that for many known examples of minimal time in the parabolic setting, this inequality recovers the value of this minimal time.

Published
2024
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6. Impact of growth conditions on the domain nucleation and domain wall propagation in Pt/Co/Pt stacks

Author

Quinteros, C. P., Burgos, M. J. Cortes, Albornoz, L. J., Gomez, J., Granell, P., Golmar, F., Ibarra, M. L., Bustingorry, S., Curiale, J., and Granada, M.

Subjects
Condensed Matter - Materials Science
Abstract

Understanding the effect of fabrication conditions on domain wall motion in thin films with perpendicular magnetization is a mandatory issue in order to tune their properties aiming to design spintronics devices based on such phenomenon. In this context, the present work intends to show how different growth conditions may affect domain wall motion in the prototypical system Pt/Co/Pt. The trilayers were deposited by dc sputtering, and the parameters varied in this study were the Co thickness, the substrate roughness, and the base pressure in the deposition chamber. Magneto-optical Kerr effect-based magnetometry and microscopy combined with X-ray reflectometry, atomic force microscopy, and transmission electron microscopy were adopted as experimental techniques. This permitted us to elucidate the impact on the hysteresis loops and on the domain wall dynamics, produced by different growth conditions. As other authors, we found that Co thickness is strongly determinant for both the coercive field and the domain wall velocity. On the contrary, the topographic roughness of the substrate and the base pressure of the deposition chamber evidence a selective impact on the nucleation of magnetic domains and on domain wall propagation, respectively, providing a tool to tune these properties.

Published
2020
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8. Weak-local triple derivations on C*-algebras and JB*-triples

Author

Burgos, M. J., Cabello, J. C., and Peralta, A. M.

Subjects
Mathematics - Operator Algebras
Abstract

We prove that every weak-local triple derivation on a JB$^*$-triple $E$ (i.e. a linear map $T: E\to E$ such that for each $\phi \in E^*$ and each $a\in E$, there exists a triple derivation $\delta_{a,\phi} : E\to E$, depending on $\phi$ and $a$, such that $\phi T(a) = \phi \delta_{a,\phi} (a)$) is a (continuous) triple derivation.

Published
2016

16. Gaps in HIV and Hepatitis C Testing Among 3486 HIV-Negative Men Who have Sex with Men in Spain in the Era of Highly Effective Antiviral Therapies.

Author

Politi, Julieta, Donat, Marta, Guerras, Juan Miguel, Ayerdi, Oskar, Palma, David, García, Jorge Néstor, Barrio, Gregorio, Belza, María José, The Methysos Project Group, del Burgos, M. C., Romero, C. P., Bueno, J. A. S. J., Urrestarazu, F. R., Ospina, J. E., Gutiérrez, M. A., del Romero, J., Rodríguez, C, del Corral Del Campo, S., Zamora, N. J., and Fernández, M. R.

Subjects
DIAGNOSIS of HIV infections, HEPATITIS C diagnosis, RISK-taking behavior, CROSS-sectional method, MEDICAL screening, REGRESSION analysis, HEALTH attitudes, QUESTIONNAIRES, DISEASE prevalence, RESEARCH funding, MEN who have sex with men, SOCIODEMOGRAPHIC factors, PROBABILITY theory
Abstract

High uptake of HIV and hepatitis C (HCV) testing in Gay, bisexual, and other men who have sex with men (GBMSM) is needed to interrupt transmission. The objective was to identify subgroups with increased probability of lack of testing among HIV-negative GBMSM in Spain. Cross-sectional study including 3486 HIV-negative GBMSM attending prevention facilities in Madrid and Barcelona, 2018–2020. Data came from self-administered online sociodemographic, health, and risk behaviors questionnaires. Outcomes were lack of HCV (lifetime) and HIV (lifetime, last year) testing. Crude and adjusted prevalences and prevalence ratios were assessed for each outcome using negative binomial regression models. Lifetime lack of HIV and HCV testing prevalence was 6.3% and 35.8%, respectively, while lack of HIV testing in the last year was 22.4%. Prevalences were also substantial in GBMSM with high-risk behaviors. After sociodemographic adjustment, the highest probability of lack of HCV testing (lifetime) and HIV (last year) was among GBMSM with insufficient viral hepatitis knowledge, no history of STI, or HCV (or HIV) testing, aged < 25, non-outness about sex life with men, and less high-risk behaviors. Lack of HCV (lifetime) and HIV testing (last year) among HIV-negative GBMSM in Spain is still high, despite high-risk behaviors. [ABSTRACT FROM AUTHOR]

Published
2024
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18. A cooperative interaction between LPHN3 and 11q doubles the risk for ADHD

Author

Jain, M, Vélez, JI, Acosta, MT, Palacio, LG, Balog, J, Roessler, E, Pineda, D, Londoño, AC, Palacio, JD, Arbelaez, A, Lopera, F, Elia, J, Hakonarson, H, Seitz, C, Freitag, CM, Palmason, H, Meyer, J, Romanos, M, Walitza, S, Hemminger, U, Warnke, A, Romanos, J, Renner, T, Jacob, C, Lesch, K-P, Swanson, J, Castellanos, FX, Bailey-Wilson, JE, Arcos-Burgos, M, and Muenke, M

Subjects
Biomedical and Clinical Sciences, Biological Psychology, Clinical and Health Psychology, Clinical Sciences, Psychology, Neurosciences, Genetics, Attention Deficit Hyperactivity Disorder (ADHD), Mental Health, 2.1 Biological and endogenous factors, Aetiology, Aspartic Acid, Attention Deficit Disorder with Hyperactivity, Brain, Case-Control Studies, Choline, Chromosomes, Human, Pair 11, Genetic Linkage, Genetic Predisposition to Disease, Glutamine, Humans, Inositol, Magnetic Resonance Spectroscopy, Methylphenidate, Polymorphism, Single Nucleotide, Protons, Receptors, G-Protein-Coupled, Receptors, Peptide, ADHD, genetic interaction, LPHN3, NCAM1, DRD2, Biological Sciences, Medical and Health Sciences, Psychology and Cognitive Sciences, Psychiatry, Clinical sciences, Biological psychology, Clinical and health psychology
Abstract

In previous studies of a genetic isolate, we identified significant linkage of attention deficit hyperactivity disorder (ADHD) to 4q, 5q, 8q, 11q and 17p. The existence of unique large size families linked to multiple regions, and the fact that these families came from an isolated population, we hypothesized that two-locus interaction contributions to ADHD were plausible. Several analytical models converged to show significant interaction between 4q and 11q (P

Published
2012

19. Pooling/bootstrap-based GWAS (pbGWAS) identifies new loci modifying the age of onset in PSEN1 p.Glu280Ala Alzheimer's disease

Author

Velez, J I, Chandrasekharappa, S C, Henao, E, Martinez, A F, Harper, U, Jones, M, Solomon, B D, Lopez, L, Garcia, G, Aguirre-Acevedo, D C, Acosta-Baena, N, Correa, J C, Lopera-Gomez, C M, Jaramillo-Elorza, M C, Rivera, D, Kosik, K S, Schork, N J, Swanson, J M, Lopera, F, and Arcos-Burgos, M

Subjects
PSEN1
Abstract

The literature on GWAS (genome-wide association studies) data suggests that very large sample sizes (for example, 50,000 cases and 50,000 controls) may be required to detect significant associations of genomic regions for complex disorders such as Alzheimer's disease (AD). Because of the challenges of obtaining such large cohorts, we describe here a novel sequential strategy that combines pooling of DNA and bootstrapping (pbGWAS) in order to significantly increase the statistical power and exponentially reduce expenses. We applied this method to a very homogeneous sample of patients belonging to a unique and clinically well-characterized multigenerational pedigree with one of the most severe forms of early onset AD, carrying the PSEN1 p.Glu280Ala mutation (often referred to as E280A mutation), which originated as a consequence of a founder effect. In this cohort, we identified novel loci genome-wide significantly associated as modifiers of the age of onset of AD (CD44, rs187116, P=1.29 × 10−12; NPHP1, rs10173717, P=1.74 × 10−12; CADPS2, rs3757536, P=1.54 × 10−10; GREM2, rs12129547, P=1.69 × 10−13, among others) as well as other loci known to be associated with AD. Regions identified by pbGWAS were confirmed by subsequent individual genotyping. The pbGWAS methodology and the genes it targeted could provide important insights in determining the genetic causes of AD and other complex conditions.

Published
2012

20. Creación de problemas de proporcionalidad en la formación de docentes de primaria

Author

Burgos, M. and Chaverri, J. H.

Subjects
proporcionalidade, formación de docentes, proporcionalidad, conocimiento didáctico-matemático, Creación de problemas, proportionality, formação de professores, Problem creation, didactic-mathematical knowledge, criação de problemas, conhecimento didático-matemático, teacher education
Abstract

[Objetivo]El objetivo de este artículo es describir y analizar una intervención formativa con futuro personal docente de primaria, dirigida a desarrollar la competencia para crear problemas de proporcionalidad mediante la variación de un problema inicial y la elaboración a partir de un requerimiento didáctico-matemático.[Metodología]Se trata de un estudio cualitativo e interpretativo que adopta una metodología propia de las investigaciones de diseño o ingeniería didáctica. Tanto en el diseño de la intervención, como en el análisis de contenido de las respuestas de los sujetos participantes se emplean herramientas teóricas y metodológicas del enfoque ontosemiótico. Se trabaja con un grupo de 127 estudiantes para docentes de Educación Primaria de la Universidad de Granada, España; organizados en 33 equipos para responder a dos consignas sobre creación de problemas.[Resultados]Los resultados muestran que los sujetos participantes crean con mayor frecuencia problemas pertinentes mediante la variación de un problema dado, pero que no logran crear problemas que permitan, de manera específica, distinguir situaciones proporcionales de aditivas a partir de un requerimiento didáctico-matemático.[Conclusiones]Se concluye que los futuros maestros y maestras manifiestan un conocimiento didáctico y matemático insuficiente para crear problemas de proporcionalidad exitosamente. Por esto es necesario que los programas de formación refuercen las estrategias para desarrollar esta tarea, incorporándola como recurso didáctico en el proceso de enseñanza, y mejorando la competencia para el análisis de la actividad matemática del futuro profesorado.

Published
2023

26. Abrupt and persistent atmospheric circulation changes in the North Atlantic under La Niña conditions

Author

Ministerio de Ciencia e Innovación (España), Universidad Complutense de Madrid, García-Burgos M., Gómara, I., Rodríguez-Fonseca, Belén, González-Alemán, J.J., Zurita-Gotor, Pablo, Ayarzagüena , B., Ministerio de Ciencia e Innovación (España), Universidad Complutense de Madrid, García-Burgos M., Gómara, I., Rodríguez-Fonseca, Belén, González-Alemán, J.J., Zurita-Gotor, Pablo, and Ayarzagüena , B.

Abstract

Several recent studies have linked the exceptional North Atlantic and Eurasian atmospheric evolution during late February and March 2018 to the Sudden Stratospheric Warming (SSW) that took place a few weeks earlier. February 2018 was characterized by an abrupt transition from the positive to the negative phase of the North Atlantic Oscillation (NAO) and a subsequent persistence of the negative NAO for several weeks. This paper investigates the contribution of atmospheric and oceanic phenomena to both the 2018 event and a set of 19 identified analogues (including the former) for the period 1959–2022. Evidence is given that La Niña conditions in the tropical Pacific and upstream North Atlantic cyclones play an important role as a trigger for these events. Ensuing two-way tropospheric-stratospheric coupling and eddy feedbacks provide extended-range persistence for negative NAO conditions. These results may help improve the prediction of such exceptional events.

Published
2023

27. Jet configurations leading to extreme winter temperatures over Europe

Author

Ministerio de Ciencia e Innovación (España), García-Burgos M., Ayarzagüena B., Barriopedro, David, García-Herrera R., Ministerio de Ciencia e Innovación (España), García-Burgos M., Ayarzagüena B., Barriopedro, David, and García-Herrera R.

Abstract

The North Atlantic eddy-driven jet (EDJ) is the main driver of winter weather in Europe and has often been described by its latitude or strength. Here, we show that the influence of the EDJ on European winter temperature extremes can be better characterized by a multiparametric perspective that accounts for additional aspects of the EDJ structure (tilt, zonal elongation, etc.). We identify four regions where extreme temperatures are distinctly associated with the EDJ: Scandinavia, Central Europe, Eastern Europe, and Western Mediterranean (WMED). Overall, the anomalous horizontal advection induced by blockings during cold spells and enhanced westerlies during warm events is the main mechanism leading to extreme event occurrence. However, diabatic processes play an important role in WMED region. Both processes generate asymmetric effects in minimum and maximum temperatures contributing to higher intensities of cold than warm events. These extreme events are associated with different EDJ configurations, which typically involve perturbed EDJs during cold spells and strong tilted EDJs during warm events, but with important variations depending on the region. In almost every region, the combined effects of more than two EDJ parameters yield significant increases in the probability of cold and warm events, suggesting an oversimplification of traditional approaches based on a single EDJ parameter. We show, using logistic regression models, that, although important, latitude and intensity are often unable to discriminate unequivocally the region of extreme event occurrence, and in some regions, they do not drive the largest changes in the odds of extremes.

Published
2023

30. Investigación académica: Recolección de datos, tecnologización y pandemia

Author

Useche, M. C., Pereira Burgos, M., and Artigas, W.

Abstract

Desde que el Covid-19 fue declarado pandemia, los investigadores académicos han procurado mantener la continuidad de los procesos científicos y superar las dificultades del trabajo de campo; eso motivó a explorar las nuevas formas de recolección de datos adaptadas a los cambios impuestos desde la pandemia. La metodología empleada fue exploratoria-documental, centrada en los nuevos medios utilizados por la investigación académica y la forma en que los instrumentos han tenido que adaptarse a las limitaciones sociales impuestas en las naciones. Los resultados evidencian que gracias al teletrabajo y a las tecnologías de información y comunicación, se ha podido continuar recopilando datos desde entornos virtuales, lo cual ha implicado reconsiderar criterios y herramientas. Se concluye que la existencia de renovadas formas de recolección de datos está marcada principalmente por los medios, destacando que el uso de las redes sociales y académicas ha ampliado sus fronteras, lo cual ha sido aprovechado por los investigadores para tener un acercamiento con la realidad en la contemporaneidad.

Published
2023

33. Análisis cognitivo de tareas de comparación de probabilidades por futuro profesorado de Educación Primaria

Author

Burgos, M., López-Martín, M. M, Aguayo-Arriagada, C. G., and Albanese, V.

Subjects
Probabilidade, Razonamiento proporcional, Teachers' education, Formación de profesores, Enfoque ontosemiótico, Análisis cognitivo, Abordagem ontosemiótica, Raciocínio proporcional, Onto-semiotic approach, Cognitive analysis, Proportional reasoning, Análise cognitiva, Probabilidad, Probability, Formação de professores
Abstract

Para favorecer el aprendizaje de las matemáticas, el profesorado debe ser capaz de analizar, interpretar y evaluar la actividad matemática de sus estudiantes, tomando decisiones sobre la comprensión y dificultades que muestran al resolver tareas matemáticas. Esta competencia de análisis cognitivo permite, al docente, comprender los procesos de aprendizaje matemático y establecer diferentes posibilidades de institucionalización del conocimiento matemático implicado. [Objetivo] El presente trabajo tiene como objetivo describir los resultados de la evaluación de los conocimientos y competencias de futuros profesores de Educación Primaria para interpretar las respuestas de estudiantes a tareas de comparación de probabilidades, identificar estrategias incorrectas y reconocer razonamiento proporcional en la actividad matemática. Asimismo, se analizan las distintas formas de actuación que proponen los futuros docentes con objeto de que los alumnos superen las dificultades que los llevaron a dar una solución inadecuada. [Metodología] Para tal fin, se ha realizado una investigación de carácter descriptivo y cualitativo, para la cual se ha contado con la colaboración de 116 futuros profesores de Educación Primaria de la Universidad de Almería (España). La intervención se llevó a cabo una vez finalizado el proceso de formación en torno a los contenidos matemáticos del Bloque de Estadística y Probabilidad. [Resultados] Entre los resultados obtenidos destacamos un conocimiento didáctico-matemático del razonamiento proporcional y probabilístico que impide a los futuros profesores interpretar y tomar decisiones en relación con las respuestas de los alumnos. [Conclusiones] Estos resultados ponen de manifiesto la necesidad de implementar intervenciones formativas que permitan solventar adecuadamente estas situaciones habituales en los centros educativos.

Published
2022

35. EL GESTOR DEPORTIVO DE CENTROS FITNESS PRIVADOS DE ANDALUCÍA.

Author

Burgos, M., Torres, B., and Cepero, M.

Subjects
MANAGERS of sports teams, PRIVATE sector, EMPLOYEE seniority, SPORTS administration, GENDER
Abstract

Copyright of Journal of Sport & Health Research is the property of Journal of Sport & Health Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2023
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36. Spatial distribution patterns of the striped venus clam (Chamelea gallina, L. 1758) natural beds in the Gulf of Cádiz (SW Spain)

Author

Delgado, M. (Marina), Román-Moreno, S. (Sara), Silva, L. (Luis), Llorens-Escrich, S. (Susana), Rodríguez-Rúa, A. (Ana), Cojan-Burgos, M. (Miguel), and Marco-Herrero, E. (Elena)

Subjects
monitoring, Medio Marino, Centro Oceanográfico de Cádiz, bottom temperature, turbidity, amplitude, organic matter
Abstract

VENUS, Estudio integral de los bancos naturales de moluscos bivalvos en el Golfo de Cádiz para su gestión sostenible y la conservación de sus hábitats asociados

Published
2022

41. A multi-parametric perspective of the North Atlantic eddy-driven jet

Author

Barriopedro, David, Ayarzagüena B., García-Burgos M., García-Herrera R., Barriopedro, David, Ayarzagüena B., García-Burgos M., and García-Herrera R.

Abstract

The North Atlantic eddy-driven jet (EDJ) is an essential component of the Euro-Atlantic atmospheric circulation. It has been typically described in terms of latitude and intensity but this is not enough to fully characterize its variability and complex EDJ configurations. Here, we present a set of daily parameters of the EDJ based on low-tropospheric zonal wind data for the 1948-2020 period. They describe the intensity, sharpness, location, edges, tilt and other zonal asymmetries of the EDJ, therefore dissecting its structure beyond the latitudinal regimes. This allows for assessments of specific EDJ aspects and a multi-parametric treatment of EDJ configurations in a manageable way. Overall, variations in EDJ parameters reflect distinctive patterns of eddy forcing and wave breaking, with anticyclonic eddies playing a major role in shaping the EDJ structure. A multimodal behavior of the EDJ is only detected in latitude, which largely influences the longitudinal position of the EDJ. Other aspects of the EDJ are less constrained by the latitude and display a variety of configurations. Four multi-parametric states (northern, central, tilted and split EDJs) provide a satisfactory description of recurrent patterns of the EDJ. They participate in meridional migrations of the EDJ, but yield less dramatic transitions than viewed from the latitudinal perspective. Finally, the EDJ parameters help to better understand the EDJ influence on European climate. In many regions, latitude and intensity contain limited information on near-surface anomalies, and their signals can be masked by the additional effect of other EDJ parameters.

Published
2022

42. A multiparametric perspective of the North Atlantic eddy-driven jet: configurations, regional impacts and remote drivers

Author

Barriopedro, David, García-Burgos M., Ayarzagüena B., García Herrera, Ricardo, Barriopedro, David, García-Burgos M., Ayarzagüena B., and García Herrera, Ricardo

Abstract

The North Atlantic eddy-driven jet (EDJ) is the most outstanding component of the Euro-Atlantic atmospheric circulation. Classically, the winter EDJ variability has been described in terms of latitude and intensity. However, this classification has recently been shown as incomplete to fully characterize more complex EDJ states. For instance, the three well established latitudinal states of the EDJ do not match the four preferred flow regimes of the Euro-Atlantic sector. A possible solution to this trouble would be the additional consideration of other EDJ characteristics, such as the tilt, waviness or longitudinal extension among others, but this has not been investigated yet. This study presents a set of daily parameters of the North Atlantic EDJ that allows for a dissection of the EDJ structure beyond the well-established trimodality in reanalysis data. The set is composed by intensity, sharpness, position, latitudinal boundaries, longitudinal extension, tilt and zonal asymmetries, which provides a manageable treatment of EDJ configurations without the need of high-dimensional 2-D fields. The parameters are computed through new developed diagnostics based on winter North Atlantic daily (zonal) wind, averaged between 925-700 hPa. The multi-parametric approach allowso deepen the structure of the EDJ, as well as the impacts and drivers of its variability. Recurrent states of the EDJ are assessed via multiparametric clustering, which is able to reconstruct the trimodality of the EDJ and more complex EDJ configurations described in the literature. Furthermore, the considered parameters turn useful for the study of regional surface impacts of the EDJ, which are better explained by a combination of parameters rather than changes in individual parameters such as the jet latitude. Lastly, the influence of a selected number of potential external drivers of the EDJ is analysed by means of linear regressions and composite analyses based on reanalysis data. The winter stratosp

Published
2022

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