636 research outputs found
About the Teaching and Learning of Differentiability for Piecewise Functions in Science Degrees’ First-Year Calculus Courses
In this work, we present an issue we have observed over the last several years in the first year of Spanish science degrees’ (such as mathematics, physics or engineering) calculus courses. It is related to the study of differentiability of piecewise one real variable real functions at a point. We have analyzed how students study the differentiability of piecewise functions at a point, explaining the students’ work and reasoning and commenting about the common misunderstandings we have found. Then, we have researched about how to help the students in their learning process related to this calculus concept, and we have also used several activities or ways to work: student meeting groups to talk about their worries and misunderstandings, mathematical definitions, explanations and theory and also working out specific examples
The structure of rotating stratified flows
Peer ReviewedPostprint (author's final draft
Hidradenitis supurativa: epidemiologÃa, clÃnica y comorbilidades
[ES] Introducción: La hidradenitis supurativa (HS) es una enfermedad inflamatoria crónica de la unidad pilosebácea que afecta a las grandes áreas intertriginosas corporales. Existen múltiples factores implicados en su patogenia: se trata de un desequilibrio del sistema inmune en personas genéticamente predispuestas, sobre las que actúan diversos factores externos, como desencadenantes o exacerbantes de la enfermedad. Esta patologÃa asocia múltiples comorbilidades, y tiene una gran repercusión fÃsica y psicológica en estos pacientes. La literatura cientÃfica publicada hasta la fecha sobre su etiopatogenia, caracterÃsticas epidemiológicas y asociaciones sistémicas es todavÃa limitada.
Objetivo: Describir de manera retrospectiva las caracterÃsticas epidemiológicas, clÃnicas y comorbilidades de los pacientes que acuden a la consulta monográfica de hidradenitis supurativa del Hospital Universitario de Cruces.
Material y métodos: Se recoge una muestra de 66 pacientes que acuden a la consulta monográfica de hidradenitis supurativa entre enero y diciembre de 2016. Se revisan caracterÃsticas epidemiológicas (sexo, edad, edad al diagnóstico, tiempo de evolución de la enfermedad, antecedentes familiares y servicio de derivación), clÃnicas (estadio Hurley) y asociaciones sistémicas (tabaquismo, obesidad, sÃndrome metabólico, sÃndrome de ovario poliquÃstico, enfermedad inflamatoria intestinal y otras).
Resultados: El 53% de los pacientes de la serie fueron hombres y 47% mujeres, con una edad media de 40.9 años. La edad media al diagnóstico fue de 22.1 años, y el tiempo de evolución medio de 18.7 años. La mitad de los pacientes tuvieron antecedentes familiares, y 70% fueron derivados a la consulta de HS por dermatólogos de los ambulatorios que cubren la OSI del Hospital Universitario de Cruces. En cuanto a la gravedad de la enfermedad en función de la clasificación de Hurley, 23% fueron grado I, 47% grado II y 30% grado III, siendo mayor la proporción de hombres en el estadio III (40%) con respecto a las mujeres (13.4%). Por otro lado, casi el 80% de los pacientes son o han sido fumadores activos, y 85% mostraron un peso elevado (IMC>25kg/m2). La prevalencia de sÃndrome metabólico fue de 7.6% y de enfermedad inflamatoria intestinal 6%. De las mujeres en edad fértil, 23% asociaron sÃndrome de ovario poliquÃstico y 58% observaron un agravamiento de las lesiones con la menstruación. Se encontraron otras comorbilidades en nuestra muestra, a destacar la patologÃa psiquiátrica, y ningún caso de carcinoma epidermoide.
Conclusiones: La hidradenitis supurativa suele diagnosticarse tras la pubertad, y pese a ser más prevalente en mujeres, su gravedad es mayor en hombres. No obstante, más de la mitad de los pacientes de nuestra muestra fueron hombres, dado que éstos muestran mayor severidad de la enfermedad, y generalmente son aquellos casos de mayor grado Hurley los que no se pueden manejar de manera ambulatoria y son derivados a la consulta monográfica de HS del hospital. Existen diversos factores implicados en su etiopatogenia, entre los que destaca un componente genético de herencia autosómica dominante. Además, en nuestra serie hemos podido corroborar que la HS asocia múltiples factores de riesgo y comorbilidades, tales como la obesidad y el tabaquismo, que parecen estar implicados como desencadenantes o exacerbantes de la enfermedad. Destacamos también su relación con el sÃndrome de ovario poliquÃstico y la presencia de brotes premenstruales, asà como una mayor prevalencia de comorbilidades psiquiátricas, en especial trastornos de ansiedad y depresivos
Null-Control and Measurable Sets
We prove the interior and boundary null-controllability of some parabolic
evolutions with controls acting over measurable sets.Comment: Two remarks adde
Fractal approach of turbulent dispersion
There are several techniques suitable for measuring and modelling dispersion from scalar or velocity-field measurements in a turbulent flow. Each of these has peculiar features and sometimes, even different scaling, and a careful choice has to be made depending on the kind of information available and needed. A useful way to investigate diffusion is to make use of the fractal and multifractal information that ocean and atmospheric flows provide. Here we present some fractal based techniques, where the velocity and scalar fields are related to the spectral spatial information that they provide and are used to predict diffusivity and mixing.In addition an Eulerian description can be obtained by interpolation from Lagrangian information, which is much easier to model via Kinematic Simulation or synthetic turbulence type models, because the detail velocity field is eventually sampled in a random statistical way in the whole domain during their time evolution. It is not possible to get reliable Lagrangian information using PIV since the transformation from the Eulerian description to the Lagrangian one implies an integration in time of the velocity field, especially when considering phenomena that show high sensitivity to initial conditions (turbulent flows). We show some examples of oil spill dispersion in the ocean surface and discuss several multifractal and scaling approaches.Peer ReviewedPostprint (published version
Large eddy simulation and laboratory experiments on the decay of grid wakes in strongly stratified flows
A detailed analysis of the flow structure resulting from the combination
of turbulence and internal waves is carried out and visualized by means
of the Schlieren method on waves in a strongly stratified fluid at the Laboratory of the IPM in Moscow. The joint appearance of the more regular internal wave oscillations and the small-scale turbulence that is confined vertically to the Ozmidov length scale favours the use of a simple geometrical analysis to investigate their time-space span and evolution. This provides useful information on the collapse of internal wave breaking processes in the ocean and the atmosphere. The measurements were performed under a variety of linear stratifications and different grid forcing scales, combining the grid wake and velocity shear. A numerical simulation using LES on the passage of a single bar in a linearly stratified fluid medium has been compared with the experiments identifying the different influences of the environmental
agents on the actual effective vertical diffusion of the wakes. The equation of state, which connects the density and salinity, is assumed to be linear, with the coefficient of the salt contraction being included into the definition of salinity or heat. The characteristic internal waves as well as the entire beam width are related to the diameter of the bar, the Richardson number and the peak-to-peak value of oscillations. The ultimate frequency of the infinitesimal periodic internal waves is limited by the maximum buoyancy frequency relating the decrease in the vertical scale with the anisotropy of the velocity turbulent r.m.s. velocity.Peer ReviewedPreprin
Modesto tributo euskaro rendido a Cervantes en el tercer centenario de la aparición del Ingenioso Hidalgo D. Quijote de la Mancha = Donkituera umill euskalduna Cervantes-eri opatua Manchako don Quijote, seme argi ta ospatsua agertu zanetik irugarren eunki-urrunean
Copia digital. Valladolid : Junta de Castilla y León. ConsejerÃa de Cultura y Turismo, 2012-2013Contiene : Varios capÃtulos del Quijote y algunos de sus mejores refranes puestos en diversos dialectos euskaros por los señores Duvoisin, Múgica, Bustinza, Ascasubi y Zamarrip
Las historias de vida como alternativa para visibilizar los relatos y experiencias silenciadas de la educación
En este artÃculo se hace referencia a una investigación sobre la constitución de
la identidad de docentes en formación y en sus primeros años de trabajo,
buscando que emerjan relatos invisibilizados y tratando de aportar otra
dimensión de las historias de vida en educación. Una dimensión desde la que
hemos pretendido dar cuenta de la complejidad de lo que experiencia el
profesorado novel y en formación para generar micro-historias que permitan un
relato otro de la historia contemporánea de la educación. En este caso, desde y
con el profesorado que comienza en la profesión docenteThis article refers to an investigation on the constitution of teachers’ identity
during their pre-service education and their first years of work by looking for
stories where the invisible emerges and adding an activist dimension to life
histories in education. From this positionality, we attempt to account the
complexity of novice teachers’ experiences by generating micro-stories that
allow to write another history of contemporary educatio
Effect of competitive tactics on performance: The case of the pharmaceutical industry
Competitive tactics play a key role in explaining different levels of organizational
performance since they are the linkers between strategy formulation and implementation. This
study focuses on two main competitive tactics, namely, Quality-Oriented Competitive Tactic
(Quality) and Cost-Oriented Competitive Tactic (Cost), which are the ones that are closely
related to Porter’s generic competitive strategies. Apart from that, we will analyze two other
important competitive tactics, namely, Innovation-Oriented Competitive Tactic (Innovation)
and Marketing-Oriented Competitive Tactic (Marketing) which will mediate the relationship
between the main tactics and performance. Hence, we try to adopt an integrative posture by
viewing competitive tactics in the pharmaceutical industry as inextricably linked, forming the
fundamental pillars on which sustainable competitive advantage could be established
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