Subspace hypercyclicity

A bounded linear operator T on Hilbert space is subspace-hypercyclic for a subspace M if there exists a vector whose orbit under T intersects the subspace in a relatively dense set. We construct examples to show that subspace-hypercyclicity is interesting, including a nontrivial subspace-hypercyclic operator that is not hypercyclic. There is a Kitai-like criterion that implies subspace-hypercyclicity and although the spectrum of a subspace-hypercyclic operator must intersect the unit circle, not every component of the spectrum will do so. We show that, like hypercyclicity, subspace-hypercyclicity is a strictly infinite-dimensional phenomenon. Additionally, compact or hyponormal operators can never be subspace-hypercyclic.Comment: 15 page

Iced Out: How Immigration Enforcement Has Interfered with Workers’ Rights

[Excerpt] In recent years, however, our federal government’s approach to immigration enforcement has severely interfered with the protection of labor rights for immigrant workers. The single-minded focus on immigration enforcement without regard to violations of workplace laws has enabled employers with rampant labor and employment violations to profit by employing workers who are terrified to complain about substandard wages, unsafe conditions, and lack of benefits, or to demand their right to bargain collectively

Reading competition and the use of new technologies of information and communication

El siguiente artículo investigativo presenta los resultados derivados del estudio “Incidencia del uso de las Tecnologías de la Información y la Comunicación, en el desarrollo de la competencia lectora en estudiantes de 3° grado de Básica Primaria”. Se plantea la situación actual del acceso a las TIC y la calidad educativa en Colombia, específicamente la relativa al departamento del Atlántico, y a las diversas problemáticas del municipio de Malambo, señalando aquellas asociadas a la educación. El análisis desarrollado fue trabajado desde las teorías del interaccionismo simbólico de Herbert Blumer y George Mead y la Teoría del Constructivismo de Lev Vygotsky. Se desarrolló bajo la metodología del paradigma empírico analítico, es una investigación de corte cuantitativo, alcance explicativo, con un diseño cuasi-experimental. Se realizó con un grupo de trabajo y medidas pretest-postest. El análisis de los resultados permite evidenciar que la exposición a las TIC fortalece los procesos asociados con la Competencia Lectora y se resalta la necesidad de implementar las TIC en el evento pedagógico, con el fin de implementar herramientas que le permitan al estudiante mejorar sus competencias lectoras y hacer frente a las exigencias de la contemporaneidad.Abstract: The following article presents the results derived from the study “Incidence of the usage of information technology in the development of reading competency among third graders in primary school”. The current access to ICT and the education quality in Colombia is posed, specifically the one related education in the department of the Atlantic and the diverse problematic in the municipal of Malabo, pointing out those associated to education. The developed analysis was worked from Herbert Blumer and George Mead´s Symbolic Interactionism Theory and Lev Vygotsy constructivism Theory. It was developed under the method of Empirical Analytical Paradigm; it’s a quantitative research, with an explanatory scope and a quasi-experimental design. It was performed with a workgroup and pretest- postest measures. The analysis of the results show that the exposure to ICT strengths the processes associated with the reading competences and highlights the need to implement the ICT in the pedagogical event, with the means to implement tools that allow the students to improve their reading competencies and cope with the demands of the contemporary times

Electrical and Thermal Tuning of Band Structure and Defect Modes in Multilayer Photonic Crystals

We describe the main results previously studied concerning the thermal and electrical tuning of photonic band gap structures and the temperature-dependent defect modes in multilayer photonic liquid crystals using nematic liquid crystal slabs in a twisted configuration. In addition to this, we present new results regarding the electrical control of defect modes in such multilayer structures. In order to achieve this goal, we establish and solve numerically the equation governing the twisted nematic configurations under the action of the external electric field by assuming arbitrary anchoring conditions at the boundaries. After this, we write Maxwell\u27s equations in a 4 × 4 matrix representation and, by using the matrix transfer technique, we obtain the transmittance and reflectance for incident circularly polarized waves

Experience-dependent plasticity in early stations of sensory processing in mature brains: effects of environmental enrichment on dendrite measures in trigeminal nuclei.

Nervous systems respond with structural changes to environmental changes even in adulthood. In recent years, experience-dependent structural plasticity was shown not to be restricted to the cerebral cortex, as it also occurs at subcortical and even peripheral levels. We have previously shown that two populations of trigeminal nuclei neurons, trigeminothalamic barrelette neurons of the principal nucleus (Pr5), and intersubnuclear neurons in the caudal division of the spinal trigeminal nucleus (Sp5C) that project to Pr5 underwent morphometric and topological changes in their dendritic trees after a prolonged total or partial loss of afferent input from the vibrissae. Here we examined whether and what structural alterations could be elicited in the dendritic trees of the same cell populations in young adult rats after being exposed for 2 months to an enriched environment (EE), and how these changes evolved when animals were returned to standard housing for an additional 2 months. Neurons were retrogradely labeled with BDA delivered to, respectively, the ventral posteromedial thalamic nucleus or Pr5. Fully labeled cells were digitally reconstructed with Neurolucida and analyzed with NeuroExplorer. EE gave rise to increases in dendritic length, number of trees and branching nodes, spatial expansion of the trees, and dendritic spines, which were less pronounced in Sp5C than in Pr5 and differed between sides. In Pr5, these parameters returned, but only partially, to control values after EE withdrawal. These results underscore a ubiquity of experience-dependent changes that should not be overlooked when interpreting neuroplasticity and developing plasticity-based therapeutic strategies.post-print2959 K

The Forward and Backward Shift on the Hardy Space of a Tree

In this paper we initiate the study of the forward and backward shifts on the Hardy space of a tree and the little Hardy space of a tree. In particular, we investigate when these shifts are bounded, find the norm of the shifts if they are bounded, characterize the trees in which they are an isometry, compute the spectrum in some concrete examples, and completely determine when they are hypercyclic.Comment: 23 page

Midiendo los resultados del comercio agropecuario mexicano en el contexto del TLCAN

La integración comercial del TLCAN puede tener efectos positivos y negativos en las economías que la promueven, dependiendo en gran medida del grado de apertura, el tipo de competencia que se genere y el nivel de desarrollo de los países. El propósito de este trabajo es medir los resultados del comercio agropecuario en el contexto del TLCAN. Se prueba el análisis en los indicadores de creación y desviación de comercio, de especialización comercial y competitividad y el impacto por el cambio en las exportaciones e importaciones agropecuarias y productos seleccionados