Dpto. Matemáticas - Matematika Saila

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Open Access
Los retículos de las clases de Schunck normales y de las clases derivadas
(Real Sociedad Matemática Española, 1979) Lafuente López, Julio; Matemáticas; Matematika
All groups to be considered are finite. The main result of this paper is the following: the normal Schunck classes compose a complete and distributive lattice antiisomorphic to the lattice composed by the derived classes. It begins with a first section of machinery which establishes that the derived classes are precisely the classes of groups G such that every simple section of G appartains to a σ-closed class of simple groups; therefore the derived classes are a natural generalization of the classes of σ-groups. Finally we study the lattice properties of the normal Schunck classes relative to a class of groups.
Open Access
Grupos primitivos con subgrupos maximales pequeños
(Universidad Autónoma de Barcelona, Departamento de Matemáticas, 1985) Lafuente López, Julio; Matemáticas; Matematika
Open Access
Teoría de Clifford en el anillo de Burnside
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 1995) Lizasoain Iriso, María Inmaculada; Ochoa Lezaun, Gustavo; Matemáticas; Matematika
Open Access
Chaos in the libration motion of an asymmetric non-rigid spacecraft
(2004) Iñarrea, Manuel; Lanchares, Víctor; Palacián Subiela, Jesús Francisco; Pascual, Ana Isabel; Salas, José Pablo; Yanguas Sayas, Patricia; Matematika; Institute for Advanced Materials and Mathematics - INAMAT2; Matemáticas; Gobierno de Navarra / Nafarroako Gobernua
We study the libration motion dynamics of an asymmetric spacecraft in circular orbit under the influence of a gravity gradient torque
Open Access
Design of low-cost smart accelerometers
(Universitat Politècnica de Catalunya, 2005) Carlosena García, Alfonso; López Martín, Antonio; Massarotto, Marco; Cruz Blas, Carlos Aristóteles de la; Lecumberri Villamediana, Pablo; Gómez Fernández, Marisol; Pintor Borobia, Jesús María; Gárriz Sanz, Sergio; Ingeniería Eléctrica y Electrónica; Matemáticas; Ingeniería Mecánica, Energética y de Materiales; Ingeniaritza Elektrikoa eta Elektronikoa; Matematika; Mekanika, Energetika eta Materialen Ingeniaritza
The goal of this project is to design a low-cost smart accelerometer, making use of a piezoelectric element as basic sensing material, and adding a mixed-mode conditioning circuit.
Open Access
The lattice of fitting classes which are right extensible by soluble groups
(Universidad Autónoma de Barcelona, Departamento de Matemáticas, 2005) Iranzo, M.J.; Lafuente López, Julio; Pérez Monasor, F.; Matemáticas; Matematika
In this paper we study the set of fitting classes which are right extensible by soluble groups ordered by the inclusion relation. The consideration of the associated lattices gives rise to new fitting classes and it allows to obtain some injectivity criteria for general fitting classes.
Open Access
Computation of greatest common divisor for the blind deconvolution of transient impulsive signals
(Universitat Politècnica de Catalunya, 2005) Lecumberri Villamediana, Pablo; Gómez Fernández, Marisol; Carlosena García, Alfonso; Matemáticas; Ingeniería Eléctrica y Electrónica; Matematika; Ingeniaritza Elektrikoa eta Elektronikoa
We propose a new blind deconvolution method for transient impulsive signals in a single input – multiple output (SIMO) system. The method exploits the data redundancy inherent to SIMO multichannel systems to obtain an estimation of the input signal. The method is built upon the assumptions of finite-length signals and channel diversity.
Open Access
Valoración de la capacidad funcional en el ámbito domiciliario y en la clínica. Nuevas posibilidades de aplicación de la acelerometría para la valoración de la marcha, equilibrio y potencia muscular en personas mayores
(Gobierno de Navarra, 2008) Izquierdo Redín, Mikel; Martínez Ramírez, Alicia; Larrión, J. L.; Irujo Espinosa, M.; Gómez Fernández, Marisol; Matemáticas; Matematika
Dentro de cualquier población de individuos mayores de 65 años, una proporción sustancial (entre el 6% y el 25%) sufre diferentes síntomas del síndrome de fragilidad. A pesar de la complejidad del termino fragilidad y de las imprecisiones en cuanto a su definición existe un consenso sobre sus síntomas y signos. Las personas que poseen este síndrome presentan pérdidas de fuerza muscular, fatiga, disminución de la actividad física, con un aumento del riesgo de padecer anorexia-pérdida de peso, delirium, hospitalización, declive funcional, deterioro cognitivo, mortalidad, ingreso en residencias, caídas e inestabilidad. Bajo este contexto, surge la necesidad de desarrollar tests que sean capaces de predecir de la forma más precoz posible la fragilidad y la discapacidad. La acelerometría es una herramienta adecuada para la monitorización de movimientos humanos de una forma objetiva y fiable, aplicable en la vida diaria de los sujetos sin implicar grandes costes. Los acelerómetros están siendo utilizados en la monitorización de diferentes movimientos. Se pueden obtener una amplio abanico de medidas como: clasificación de movimientos, valoración del nivel de actividad física, estimación del gasto de energía metabólica, medida del equilibrio, ritmo de marcha y control al levantarse-sentarse. Combinando la acelerometría con giróscopos y magnetómetros se podrá añadir información relacionada con la orientación y los cambios de posición. Esta revisión analiza las herramientas y tecnologías existentes que puedan llegar a detectar de manera precoz posibles signos y síntomas de la fragilidad y permitan a los individuos vivir autónomamente de forma más prolongada y en condiciones de mayor seguridad.
Open Access
Semicontinuous planar total preorders on non-separable metric spaces
(The Korean Mathematical Society, 2009) Campión Arrastia, María Jesús; Candeal, Juan Carlos; Induráin Eraso, Esteban; Matemáticas; Matematika
We prove that every non-separable connected metric space can be endowed with a total preorder that is order-isomorphic to a nonrepresentable subset of the lexicographic plane and semicontinuous with respect to the metric topology.
Open Access
The Tsirelson space tau (p) has a unique unconditional basis up to permutation for 0 < p < 1
(Hindawi Publishing Corporation, 2009) Albiac Alesanco, Fernando José; Leránoz Istúriz, María Camino; Matemáticas; Matematika
We show that the p-convexified Tsirelson space tau((p)) for 0 < p < 1 and all its complemented subspaces with unconditional basis have unique unconditional basis up to permutation. The techniques involved in the proof are different from the methods that have been used in all the other uniqueness results in the nonlocally convex setting. Copyright (C) 2009 F. Albiac and C. Leranoz.
Open Access
On perfectly homogeneous bases in quasi-Banach spaces
(Hindawi Publishing Corporation, 2009) Albiac Alesanco, Fernando José; Leránoz Istúriz, María Camino; Matemáticas; Matematika
For 0 < p < infinity the unit vector basis of l(p) has the property of perfect homogeneity: it is equivalent to all its normalized block basic sequences, that is, perfectly homogeneous bases are a special case of symmetric bases. For Banach spaces, a classical result of Zippin (1966) proved that perfectly homogeneous bases are equivalent to either the canonical c(0)-basis or the canonical l(p)-basis for some 1 <= p < infinity. In this note, we show that (a relaxed form of) perfect homogeneity characterizes the unit vector bases of l(p) for 0 < p < 1 as well amongst bases in nonlocally convex quasi-Banach spaces. Copyright (C) 2009 F. Albiac and C. Leranoz.
Open Access
Distribution patterns of infection with multiple types of human papillomaviruses and their association with risk factors
(Public Library of Science, 2011) Soto de León, Sara; Camargo, Milena; Sánchez, Ricardo; Muñoz, Marina; Pérez Prados, Antonio; Purroy Unanua, Antonio; Patarroyo, Manuel Elkin; Patarroyo, Manuel Alfonso; Matemáticas; Matematika
Background: Infection with multiple types of human papillomavirus (HPV) is one of the main risk factors associated with the development of cervical lesions. In this study, cervical samples collected from 1, 810 women with diverse sociocultural backgrounds, who attended to their cervical screening program in different geographical regions of Colombia, were examined for the presence of cervical lesions and HPV by Papanicolau testing and DNA PCR detection, respectively. Principal Findings: The negative binomial distribution model used in this study showed differences between the observed and expected values within some risk factor categories analyzed. Particularly in the case of single infection and coinfection with more than 4 HPV types, observed frequencies were smaller than expected, while the number of women infected with 2 to 4 viral types were higher than expected. Data analysis according to a negative binomial regression showed an increase in the risk of acquiring more HPV types in women who were of indigenous ethnicity (+37.8%), while this risk decreased in women who had given birth more than 4 times (-31.1%), or were of mestizo (-24.6%) or black (-40.9%) ethnicity. Conclusions: According to a theoretical probability distribution, the observed number of women having either a single infection or more than 4 viral types was smaller than expected, while for those infected with 2-4 HPV types it was larger than expected. Taking into account that this study showed a higher HPV coinfection rate in the indigenous ethnicity, the role of underlying factors should be assessed in detail in future studies.
Open Access
Naturaleza del razonamiento algebraico elemental
(UNESP, 2012) Godino, Juan D.; Castro, Walter F.; Aké, Lilia P.; Wilhelmi, Miguel R.; Matemáticas; Matematika
La introducción del razonamiento algebraico en educación primaria es un tema de interés para la investigación e innovación curricular en didáctica de las matemáticas, y presupone una visión ampliada de la naturaleza del álgebra escolar. En este trabajo proponemos una manera de concebir el razonamiento algebraico, basada en los tipos de objetos y procesos matemáticos introducidos en el enfoque ontosemiótico del conocimiento matemático. En síntesis, la consideración de una práctica matemática como algebraica se basará en la intervención de procesos de generalización y simbolización, junto con otros objetos usualmente considerados como algebraicos, tales como relaciones binarias, operaciones, funciones y estructuras. Esta forma de concebir el álgebra elemental es contrastada con las caracterizaciones dadas por otros autores. Asimismo, proponemos una tipología de configuraciones algebraicas que permite definir grados de algebrización de la actividad matemática.
Open Access
Desarrollo del pensamiento combinatorio: evaluación y materiales
(2013) Lasa Oyarbide, Aitzol; Wilhelmi, Miguel R.; Belletich Ruiz, Olga; Matemáticas; Matematika; Psicología y Pedagogía; Psikologia eta Pedagogia
Profesores en formación analizan en una tarea de recuento la pertinencia de distintos esquemas de corrección (Wilhelmi, Belletich, Lasa y Reina, 2013). En criterio general en todos ellos es: de ejecución máxima en una evaluación sumativa. La evaluación de proceso enfatiza el proceso de construcción y comunicación de conocimientos, que es implícitamente desatendido en las evaluaciones clásicas de tipo sumativo. En esta evaluación de procesos es crucial la coherencia entre la tarea propuesta, los recursos empleados y el sistema didáctico puesto en juego, donde el medio material queda en parte determinado por el soporte empleado. Aquí, interesa determinar la importancia de la evaluación según el uso de diferentes soportes (lápiz y papel, material manipulable o software dinámico), en una tarea combinatoria de recuento de pentominós y de análisis de las propiedades isométricas de éstos.
Open Access
An evaluation of the 30-s chair stand test in older adults: frailty detection based on kinematic parameters from a single inertial unit
(BioMed Central, 2013) Millor Muruzábal, Nora; Lecumberri Villamediana, Pablo; Gómez Fernández, Marisol; Martínez Ramírez, Alicia; Izquierdo Redín, Mikel; Matemáticas; Ciencias de la Salud; Matematika; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua
Background: A growing interest in frailty syndrome exists because it is regarded as a major predictor of co-morbidities and mortality in older populations. Nevertheless, frailty assessment has been controversial, particularly when identifying this syndrome in a community setting. Performance tests such as the 30-second chair stand test (30-s CST) are a cornerstone for detecting early declines in functional independence. Additionally, recent advances in body-fixed sensors have enhanced the sensors’ ability to automatically and accurately evaluate kinematic parameters related to a specific movement performance. The purpose of this study is to use this new technology to obtain kinematic parameters that can identify frailty in an aged population through the performance the 30-s CST. Methods: Eighteen adults with a mean age of 54 years, as well as sixteen pre-frail and thirteen frail patients with mean ages of 78 and 85 years, respectively, performed the 30-s CST while threir trunk movements were measured by a sensor-unit at vertebra L3. Sit-stand-sit cycles were determined using both acceleration and orientation information to detect failed attempts. Movement-related phases (i.e. impulse, stand-up, and sit-down) were differentiated based on seat off and seat on events. Finally, the kinematic parameters of the impulse, stand-up and sit-down phases were obtained to identify potential differences across the three frailty groups. Results: For the stand-up and sit-down phases, velocity peaks and “modified impulse” parameters clearly differentiated subjects with different frailty levels (p < 0.001). The trunk orientation range during the impulse phase was also able to classify a subject according to his frail syndrome (p < 0.001). Furthermore, these parameters derived from the inertial units (IUs) are sensitive enough to detect frailty differences not registered by the number of completed cycles which is the standard test outcome. Conclusions: This study shows that IUs can enhance the information gained from tests currently used in clinical practice, such as the 30-s CST. Parameters such as velocity peaks, impulse, and orientation range are able to differentiate between adults and older populations with different frailty levels. This study indicates that early frailty detection could be possible in clinical environments, and the subsequent interventions to correct these disabilities could be prescribed before further degradation occurs.
Open Access
Pre-operative ambulatory measurement of asymmetric lower limb loading during walking in total hip arthroplasty patients
(BioMed Central, 2013) Martínez Ramírez, Alicia; Weenk, Dirk; Lecumberri Villamediana, Pablo; Verdonschot, Nico; Pakvis, Dean; Veltink, Peter H.; Matemáticas; Matematika; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Background: Total hip arthroplasty is a successful surgical procedure to treat hip osteoarthritis. Clinicians use different questionnaires to assess the patient’s pain and functional capacity. Furthermore, they assess the quality of gait in a very global way. This clinical evaluation usually shows significant improvement after total hip arthroplasty, however, does not provide objective, quantifiable information about the movement patterns underlying the functional capacity, which can currently only be obtained in a gait laboratory. Instrumented force shoes can quantify gait velocity, ground reaction forces and the gait pattern easily in an outpatient setting. The main goal of this study was to investigate how mobility characteristics during walking, relate to gait velocity and questionnaire outcomes of patients with hip osteoarthritis in an outpatient setting. Methods: 22 patients with primary osteoarthritis of the hip selected for a total hip arthroplasty participated in this study. For each patient the Harris Hip Score, the Traditional Western Ontario and the McMaster Universities osteoarthritis index were administered. Subsequently, the patients were instructed to walk through the corridor while wearing instrumented shoes. The gait velocity estimated with the instrumented force shoes was validated measuring the time required to walk a distance of 10 m using a stopwatch and a measuring tape as a reference system. A regression analysis between spatial, temporal, ground reaction force parameters, including asymmetry, and the gait velocity and the questionnaires outcomes was performed. Results: The velocity estimated with the instrumented shoes did not differ significantly from the velocity measured independently. Although gait parameters correlated significantly with velocity, symmetry index parameters were not correlated with velocity. These symmetry index parameters show significant inter-limb asymmetry during walking. No correlation was found between any of the variables studied and questionnaires outcomes. Conclusion: Inter-limb asymmetry can be evaluated with the instrumented shoes supplying important additional information about the individual gait pattern, which is not represented by gait velocity and questionnaires usually used. Therefore, this new ambulatory measurement system is able to provide complementary information to gait velocity and questionnaires outcomes to assess the functional capacity of patients with hip osteoarthritis.
Open Access
Evaluación de respuestas a una tarea de recuento
(2013) Wilhelmi, Miguel R.; Belletich Ruiz, Olga; Lasa Oyarbide, Aitzol; Reina, Luis; Matemáticas; Matematika; Psicología y Pedagogía; Psikologia eta Pedagogia
La transposición didáctica explica los procesos adaptativos del saber en la escuela. Los desarrollos didácticos han puesto el énfasis en el modo en que estos procesos condicionan las intervenciones razonadas del docente en el sistema didáctico, pero no han abordado de manera sistemática el análisis de los momentos de evaluación y de los criterios de corrección de pruebas regladas. Se discute aquí si la evaluación de la actividad matemática debe quedar determinada por un criterio absoluto de ejecución máxima o si, por el contrario, debe referirse a una norma que emana del currículo. A partir de unas respuestas tipo de una tarea de recuento, profesores en formación analizan la pertinencia de distintos esquemas de corrección. El análisis arroja una gran subjetividad en la corrección, la aceptación irreflexiva de un criterio absoluto de calificación y la inobservancia de la relación entre tarea, currículo y evaluación.
Open Access
On the p-length of some finite p-soluble groups
(Springer, 2014) Ballester Bolinches, Adolfo; Esteban Romero, Ramón; Ezquerro Marín, Luis Miguel; Matemáticas; Matematika
The main aim of this paper is to give structural information of a finite group of minimal order belonging to a subgroup-closed class of finite groups and whose p-length is greater than 1, p a prime number. Alternative proofs and improvements of recent results about the influence of minimal p-subgroups on the p-nilpotence and p-length of a finite group arise as consequences of our study.
Open Access
Assessment of asymmetric leg loading before and after total hip arthroplasty using instrumented shoes
(BioMed Central, 2014) Martínez Ramírez, Alicia; Weenk, Dirk; Lecumberri Villamediana, Pablo; Verdonschot, Nico; Pakvis, Dean; Veltink, Peter H.; Matemáticas; Matematika
Background: Total hip arthroplasty is a successful surgical treatment in patients with osteoarthritis of the hip. Different questionnaires are used by the clinicians to assess functional capacity and the patient's pain, despite these questionnaires are known to be subjective. Furthermore, many studies agree that kinematic and kinetic parameters are crucial to evaluate and to provide useful information about the patient’s evolution for clinicians and rehabilitation specialists. However, these quantities can currently only be obtained in a fully equipped gait laboratory. Instrumented shoes can quantify gait velocity, kinetic, kinematic and symmetry parameters. The aim of this study was to investigate whether the instrumented shoes is a sufficiently sensitive instrument to show differences in mobility performance before and after total hip arthroplasty. Methods: In this study, patients undergoing total hip arthroplasty were measured before and 6–8 months after total hip arthroplasty. Both measurement sessions include 2 functional mobility tasks while the subject was wearing instrumented shoes. Before each measurement the Harris Hip Score and the Traditional Western Ontario and McMaster Universities osteoarthritis index were administered as well. Results: The stance time and the average vertical ground reaction force measured with the instrumented shoes during walking, and their symmetry index, showed significant differences before and after total hip arthroplasty. However, the data obtained with the sit to stand test did not reveal this improvement after surgery. Conclusions: Our results show that inter-limb asymmetry during a walking activity can be evaluated with the instrumented shoes before and after total hip arthroplasty in an outpatient clinical setting.
Open Access
Niveles de algebrización de la actividad matemática escolar: implicaciones para la formación de maestros
(Universitat Autònoma de Barcelona, 2014) Godino, Juan D.; Aké, Lilia P.; Gonzato, Margherita; Wilhelmi, Miguel R.; Matemáticas; Matematika
El desarrollo del razonamiento algebraico elemental desde los primeros niveles educativos es un objetivo propuesto en diversas investigaciones y orientaciones curriculares. En consecuencia, es importante que el profesor de educación primaria conozca las características del razonamiento algebraico y sea capaz de seleccionar y elaborar tareas matemáticas adecuadas que permitan la progresiva introducción del razonamiento algebraico en la escuela primaria. En este trabajo, presentamos un modelo en el que se diferencian tres niveles de razonamiento algebraico elemental que puede utilizarse para reconocer características algebraicas en la resolución de tareas matemáticas. Presentamos el modelo junto con ejemplos de actividades matemáticas, clasificadas según los distintos niveles de algebrización. Estas actividades pueden ser usadas en la formación de profesores a fin de capacitarlos para el desarrollo del sentido algebraico en sus alumnos.