79 research outputs found

    On the uniform convergence of continuous semigroups

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    Let Ω\Omega be a region in the complex plane C\mathbb C and let {Φt}t0\{\Phi_t \}_{t\ge 0} be a continuous semigroup of functions on Ω\Omega; that is, Φt ⁣:ΩΩ\Phi_t\colon \Omega\to\Omega is holomorphic for every t0t\ge 0, Φ0(z)=z\Phi_0(z)=z, for every zΩz\in\Omega, ΦtΦs=Φs+t\Phi_t\circ\Phi_s=\Phi_{s+t}, for every ss, t0t\ge 0, and \begin{equation*}\label{eso} \Phi_t(z)\to z\,,\quad\hbox{ as tt goes to 0+0^+,} \end{equation*} uniformly on compact subsets of Ω\Omega. Despite this definition only requires the uniform convergence on compact subsets, P. Gumenyuk proved in 2014 that, when Ω\Omega is the unit disc, the convergence is uniform on the whole D\mathbb D. When Ω\Omega is a half-plane, it is not difficult to show that the result is no longer true. In this paper, we enhance Gumenyuk's result by proving that for every continuous semigroup {Φt}t0\{\Phi_t \}_{t\ge 0} on D\mathbb D we have supzDΦt(z)z=O(t),t0+. \sup_{z\in\mathbb D} |\Phi_t(z)-z|= O(\sqrt t), \quad t\to 0^+. In addition, we provide an example showing that O(t)O(\sqrt t) is the best possible rate of uniform convergence valid for all semigroups on D\mathbb D. When Ω\Omega is a half-plane we prove that there is uniform convergence to the identity under certain boundedness conditions on the infinitesimal generator of the semigroup. These boundedness conditions are fulfilled when the semigroup {Φt}t0\{\Phi_t \}_{t\ge 0} is included in the Gordon-Hedenmalm class (the one which produces bounded composition operators on Hardy spaces of Dirichlet series). An important ingredient in the proofs of these results is the use of harmonic measures, which we have done through a classic result of M. Lavrentiev.Comment: 22 pages, 1 figur

    Composition operators on the algebra of Dirichlet series

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    The algebra of Dirichlet series A(C+)\mathcal{A}(\mathcal{C}_{+}) consists on those Dirichlet series convergent in the right half-plane C+\mathcal{C}_{+} and which are also uniformly continuous there. This algebra was recently introduced by Aron, Bayart, Gauthier, Maestre, and Nestoridis. We describe the symbols Φ:C+C+\Phi:\mathcal{C}_{+}\to\mathcal{C}_{+} giving rise to bounded composition operators CΦ\mathit{C}_{\Phi} in A(C+)\mathcal{A}(\mathcal{C}_{+}) and denote this class by GA\mathcal{G}_{\mathcal{A}}. We also characterise when the operator CΦ\mathit{C}_{\Phi} is compact in A(C+)\mathcal{A}(\mathit{C}_{+}). As a byproduct, we show that the weak compactness is equivalent to the compactness for CΦ\mathit{C}_{\Phi}. Next, the closure under the local uniform convergence of several classes of symbols of composition operators in Banach spaces of Dirichlet series is discussed. We also establish a one-to-one correspondence between continuous semigroups of analytic functions {Φt}\{\Phi_{t}\} in the class GA\mathcal{G}_{\mathcal{A}} and strongly continuous semigroups of composition operators {Tt}\{T_{t}\}, Ttf=fΦtT_{t}f=f\circ\Phi_{t}, fA(C+)f\in\mathcal{A}(\mathcal{C}_{+}). We conclude providing examples showing the differences between the symbols of bounded composition operators in A(C+)\mathcal{A}(\mathcal{C}_{+}) and the Hardy spaces of Dirichlet series Hp\mathcal{H}^{p} and H\mathcal{H}^{\infty}

    PIV measurements of the effect of pulsed blowing jet on a NACA0012 wing model

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    Wingtip vortices are present in taking off, and landing operations and their presence in airport runways must be reduced. To that end, several strategies have been considered in the last decades, being the active control one possible technical solution. To compute the effectiveness of active control that corresponds to pulsed low-blowing-ratio transverse jet for the reduction of the wingtip vortex strength, we carry out 2D-PIV measurements in a towing tank for chord-based Reynolds numbers 15000 and 20000. We consider two cases: (i) no active control Rjet=0 and (ii) pulsating radial jet of blowing-ratio Rjet smaller than 1.7 (or momentum coefficient lower than 0.12) and different Strouhal numbers ranging from 0.27 to 0.94. Our observations show that the best reduction of wingtip vortex strength takes place at the lowest Strouhal number tested. We use the maximum azimuthal velocity and vorticity together with the circulation to quantify this decrease in the vortex strength. Besides, we define the spatial evolution of a disturbance parameter which allow us to detect again the optimal frequency that leads to vortex destruction.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Cardiac electrical defects in progeroid mice and Hutchinson-Gilford progeria syndrome patients with nuclear lamina alterations

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    Hutchinson–Gilford progeria syndrome (HGPS) is a rare genetic disease caused by defective prelamin A processing, leading to nuclear lamina alterations, severe cardiovascular pathology, and premature death. Prelamin A alterations also occur in physiological aging. It remains unknown how defective prelamin A processing affects the cardiac rhythm. We show age-dependent cardiac repolarization abnormalities in HGPS patients that are also present in the Zmpste24-/- mouse model of HGPS. Challenge of Zmpste24-/- mice with the ß-adrenergic agonist isoproterenol did not trigger ventricular arrhythmia but caused bradycardia-related premature ventricular complexes and slow-rate polymorphic ventricular rhythms during recovery. Patch-clamping in Zmpste24-/- cardiomyocytes revealed prolonged calcium-transient duration and reduced sarcoplasmic reticulum calcium loading and release, consistent with the absence of isoproterenol-induced ventricular arrhythmia. Zmpste24-/- progeroid mice also developed severe fibrosis-unrelated bradycardia and PQ interval and QRS complex prolongation. These conduction defects were accompanied by overt mislocalization of the gap junction protein connexin43 (Cx43). Remarkably, Cx43 mislocalization was also evident in autopsied left ventricle tissue from HGPS patients, suggesting intercellular connectivity alterations at late stages of the disease. The similarities between HGPS patients and progeroid mice reported here strongly suggest that defective cardiac repolarization and cardiomyocyte connectivity are important abnormalities in the HGPS pathogenesis that increase the risk of arrhythmia and premature death.Peer ReviewedPostprint (published version

    Planeamiento estratégico de la educación superior privada en el Perú

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    Para desarrollar un país, se deben construir las bases necesarias que permitan proyectos sostenibles y a largo plazo, los cuales están apalancados en una buena educación y formación de los ciudadanos que conforman una sociedad; razón por la cual se toma la decisión de tratar el tema de educación. Después de realizar una investigación más a profundidad de la educación en el Perú, se considera hacer el Planeamiento Estratégico de la Educación Superior Privada en el Perú, puesto que a 2015 está pasando por un proceso de transformación importante y decisivo para el futuro del País. Para obtener las recomendaciones se ejecutó la metodología del Proceso Estratégico, mediante el cual se logró entender en qué situación se encontraba la Educación Superior Privada. Se entendió que el Decreto Ley Nº882 (1996) fue necesario para el Perú, puesto que incentivó la creación de universidades privadas con el objetivo de atender la demanda de educación. Este hecho se presentaba como una importante iniciativa del Gobierno y con lo cual se avizoraba un buen porvenir; sin embargo, el problema fue la creación de las universidades sin control y estándares mínimos de calidad educativa. En 2014 ocurrió el primer avance con la promulgación de la Ley 30220 que definía los estándares de calidad, procesos de acreditación y licenciamiento, creaba la SUNEDU, y establecía un marco legislativo y regulatorio sobre la creación de universidades. Las recomendaciones descritas soportan la misión definida, ayudando a lograr la visión trazada, soportado en los seis OLP definidos y las nueve estrategias retenidas, todo medido a través de un BSC, con el fin de lograr una educación superior peruana con altos estándares de calidad y enfocadas en tener un sistema de educación privado, de calidad, accesible, con infraestructura y certificado, con sólidas bases de ética y responsabilidad social, que apoyen el crecimiento de la sociedad y hagan del Perú un País más desarrollado y con más oportunidades para todosThe most important investment a country should make is to look into its very foundation, for which an excellent education, represents the very source of success, production, employment and entrepreneurship. After analyzing general education in Peru, we decided to emphasize this document on Strategic Planning for superior private education, since it is undergoing a transformation process aligned with the economic and social changes happening in the country, and because it is an area of decisive action towards the country’s success. In order to achieve the many recommendations we have proposed to the system, we have used the Strategic Process methodology, with what we have understood and evaluated the current context for superior private education in Peru today. We have understood that in 1996 the DL 882 was necessary because the country was in need to increase the number of education establishments in order to attend the growing demand of students. However, the problem that later arised was that the growth of universities was given without control and minimum standards, focusing only in growth, without taking quality levels into consideration. In the year 2014, when Law 30220 came into place, there was big advancements since finally there was a quality guidance that for instance established that to be a bachelor university professor. This is how the SUNEDU was created, entity which defined not only legislative processes but also enforced a specific licensing and structure on universities. The suggestions we are recommending are aligned with the mission, helping to accomplish the vision, with six long term objectives and nine strategies retain, measure, and control by a BSC, which strongly support quality education, specifically focusing on having a superior private education sector that both achieves quality education and access to as many Peruvians as possible, infrastructure, and solid moral foundations, always motivating activities such as sport; with the sole motivation of progress in our country and more opportunities for everyoneTesi

    Peptide-Protein Coassemblies into Hierarchical and Bioactive Tubular Membranes

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    Multicomponent self-assembly offers opportunities for the design of complex and functional biomaterials with tunable properties. Here, we demonstrate how minor modifications in the molecular structures of peptide amphiphiles (PAs) and elastin-like recombinamers (ELs) can be used to generate coassembling tubular membranes with distinct structures, properties, and bioactivity. First, by introducing minor modifications in the charge density of PA molecules (PAK2, PAK3, PAK4), different diffusion-reaction processes can be triggered, resulting in distinct membrane microstructures. Second, by combining different types of these PAs prior to their coassembly with ELs, further modifications can be achieved, tuning the structures and properties of the tubular membranes. Finally, by introducing the cell adhesive peptide RGDS in either the PA or EL molecules, it is possible to harness the different diffusion-reaction processes to generate tubular membranes with distinct bioactivities. The study demonstrates the possibility to trigger and achieve minor but crucial differences in coassembling processes and tune material structure and bioactivity. The study demonstrates the possibility to use minor, yet crucial, differences in coassembling processes to tune material structure and bioactivity

    NLRP3 inflammasome suppression improves longevity and prevents cardiac aging in male mice

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    While NLRP3‐inflammasome has been implicated in cardiovascular diseases, its role in physiological cardiac aging is largely unknown. During aging, many alterations occur in the organism, which are associated with progressive impairment of metabolic pathways related to insulin resistance, autophagy dysfunction, and inflammation. Here, we investigated the molecular mechanisms through which NLRP3 inhibition may attenuate cardiac aging. Ablation of NLRP3‐inflammasome protected mice from age‐related increased insulin sensitivity, reduced IGF‐1 and leptin/adiponectin ratio levels, and reduced cardiac damage with protection of the prolongation of the agedependent PR interval, which is associated with atrial fibrillation by cardiovascular aging and reduced telomere shortening. Furthermore, old NLRP3 KO mice showed an inhibition of the PI3K/AKT/mTOR pathway and autophagy improvement, compared with old wild mice and preserved Nampt‐mediated NAD+ levels with increased SIRT1 protein expression. These findings suggest that suppression of NLRP3 prevented many age‐associated changes in the heart, preserved cardiac function of aged mice and increased lifespan.Andalusian regional government; Consejería de Salud de la Junta de Andalucia, Grant/ Award Number: PI‐0036‐2014; Ministerio de economía y competitividad, Grant/Award Number: SAF2017‐84494‐C2‐1‐

    Tratado de justicia restaurativa. Un enfoque integrador

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    Esta obra nos presenta a la Justicia Restaurativa desde la configuración del derecho penal y los procesos de la misma en el orden penitenciario, en las comunidades escolares, en la igualdad de género. Realzando así mismo la habiliades del facilitador que habrá de llevarla a cabo, como parte integral de un nuevo paradigma en la formación de recursos humnos que atiendan la inminente necesidad de este tipo de ejercicio y en las redes primarias de apoyo, como elemento restaurativo para las mujeres víctimas de violencia doméstica, dónde ha crecido la respuesta de la sociedad para abatir este sector de la violenci
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