Derivation of nearest-neighbor DNA parameters in magnesium from single-molecule experiments

DNA hybridization is an essential molecular reaction in biology with many applications. The nearest-neighbor (NN) model for nucleic acids predicts DNA thermodynamics using energy values for the different base pair motifs. These values have been derived from melting experiments in monovalent and divalent salt and applied to predict melting temperatures of oligos within a few degrees. However, an improved determination of the NN energy values and their salt dependencies in magnesium is still needed for current biotechnological applications seeking high selectivity in the hybridization of synthetic DNAs. We developed a methodology based on single molecule unzipping experiments to derive accurate NN energy values and initiation factors for DNA. A new set of values in magnesium is derived, which reproduces unzipping data and improves melting temperature predictions for all available oligo lengths, in a range of temperature and salt conditions where correlation effects between the magnesium bound ions are weak. The NN salt correction parameters are shown to correlate to the GC content of the NN motifs. Our study shows the power of single-molecule force spectroscopy assays to unravel novel features of nucleic acids such as sequence-dependent salt corrections

Long-term effects of gestational nicotine exposure and food-restriction on gene expression in the striatum of adolescent rats

Gestational exposure to environmental toxins such as nicotine may result in detectable gene expression changes in later life. To investigate the direct toxic effects of prenatal nicotine exposure on later brain development, we have used transcriptomic analysis of striatal samples to identify gene expression differences between adolescent Lister Hooded rats exposed to nicotine in utero and controls. Using an additional group of animals matched for the reduced food intake experienced in the nicotine group, we were also able to assess the impact of imposed food-restriction on gene expression profiles. We found little evidence for a role of gestational nicotine exposure on altered gene expression in the striatum of adolescent offspring at a significance level of p0.5|, although we cannot exclude the possibility of nicotine-induced changes in other brain regions, or at other time points. We did, however, find marked gene expression differences in response to imposed food-restriction. Food-restriction resulted in significant group differences for a number of immediate early genes (IEGs) including Fos, Fosb, Fosl2, Arc, Junb, Nr4a1 and Nr4a3. These genes are associated with stress response pathways and therefore may reflect long-term effects of nutritional deprivation on the development of the stress system

Interferência de imagens de apego em adultos com transtorno de personalidade borderline

Interpersonal problems of people with Borderline Personality Disorder (bpd) may accentuate emotional dysregulation. The aim of this research was to investigate how individuals with bpd react to images of Secure Attachment (sa) and Insecure Attachment (ia). Participants with bpd (n = 6) were compared to a control group (n = 6) matched in number, sex and age (M = 29 years, SD = 5,49). Both groups responded to the Parental Bonding Instrument (pbi). Psychologists selected the attachment images used (n = 8). Subsequently, participants with bpd and the control group performed an Emotional Interference (ei) task and explicitly evaluated attachment images. Individuals with bpd had significantly impaired parental bonding than the control group. The bpd group evaluated the aistimuli as substantially more represen - tative of an insecure attachment than the control group and the psychologists. There was no effect of ei on the applied task. The results of this study suggest that the insecure attachment of individuals with bpd influences the explicit evaluation of attachment images.Keywords: Borderline personality disorder, attachment theory, emotional interference. Los problemas interpersonales de personas con Trastorno de Personalidad Borderline (TBP) pueden acentuar la desregulación emocional. El objetivo de esta investigación fue estudiar de qué forma individuos con tpb reaccionan a las imágenes de Apego Seguro (AS) y Apego Inseguro (AI). Los participantes con tpb (n=6) fueron comparados a un grupo control (n=6) emparejados en número, sexo y edad (M=29 años, DP=5.49). Ambos grupos respondieron al Instrumento de Vínculo Parental (IVP). Las imágenes de apego utilizadas fueron seleccionadas por psicólogos (n=8). Posteriormente, los participantes con TBP y el grupo control realizaron una tarea de Interferencia Emocional (IE) y evaluaron explícitamente las imágenes de apego. Los individuos con TBP presentaron un vínculo parental significativamente más perjudicado que el grupo control. El grupo con tpb evaluó los estímulos de ai como significativamente más representativos de un apego del tipo inseguro que del grupo control y los psicólogos. No hubo efecto de ie en la tarea aplicada. Los resultados de este estudio sugieren que el apego inseguro de individuos con TBP influencia la evaluación explícita de imágenes de apego.Palabras clave: trastorno de personalidad borderline, teoría del apego, interferencia emocional.Os problemas interpessoais de pessoas com Transtorno de Personalidade Borderline (tpb) podem acentuar a desregulação emocional. O objetivo desta pesquisa foi investigar de que forma indivíduos com tpb reagem às imagens de Apego Seguro (as) e Apego Inseguro (ai). Os participantes com tpb (n=6) foram comparados a um grupo controle (n=6) pareados em número, sexo e idade (M=29 anos, DP=5.49). Ambos os grupos responderam ao Instrumento de Vínculo Parental (ivp). As imagens de apego utilizadas foram selecionadas por psicólogos (n=8). Posteriormente, os participantes com tpb e o grupo controle realizaram uma tarefa de Interferência Emocional (ie) e avaliaram explicitamente as imagens de apego. Indivíduos com tpb apresentaram um vínculo parental significativamente mais prejudicado do que o grupo controle. O grupo com tpb avaliou os estímulos de ai como significativamente mais representativos de um apego do tipo inseguro do que o grupo controle e os psicólogos. Não houve efeito de ie na tarefa aplicada. Os resultados deste estudo sugerem que o apego inseguro de indivíduos com tpb influencia na avaliação explícita de imagens de apego.Palavras-chave: transtorno de personalidade borderline, teoria do apego, interferência emocional

The Wigner function associated to the Rogers-Szego polynomials

We show here that besides the well known Hermite polynomials, the q-deformed harmonic oscillator algebra admits another function space associated to a particular family of q-polynomials, namely the Rogers-Szego polynomials. Their main properties are presented, the associated Wigner function is calculated and its properties are discussed. It is shown that the angle probability density obtained from the Wigner function is a well-behaved function defined in the interval [-Pi,Pi), while the action probability only assumes integer values greater or equal than zero. It is emphasized the fact that the width of the angle probability density is governed by the free parameter q characterizing the polynomial.Comment: 12 pages, 2 (mathemathica) figure

Sistema de detección de tránsito vehicular

La tecnología de detección de tráfico vehicular ha demostrado ser un área de diseño avanzada, capaz de lograr mejoras sustanciales en un rango de aplicaciones debido a su paradigma de la estructura de toma de decisiones basado en el razonamiento cognitivo. El presente trabajo presenta el desarrollo de un avance en la tecnología de detección vehicular que permite incluir un modelo formal basado en un agente autónomo e inteligente capaz de detectar vehículos a través de un solo sensor, de acuerdo a las exigencias y limitaciones de las avenidas. Se utilizaron los periféricos de UART (Universal Asynchronous Receiver-Transmiter), RTC (Real Time Clock), DMA (Direct Memory Access), para el manejo de los datos, así como una aplicación como interfaz de usuario para mostrar la cantidad de tránsito. Este proceso mejora efectiva e inmediatamente la calidad del servicio en una intersección, aumentando el rendimiento de la movilidad de los vehículos. Este prototipo tiene como ventaja no solo la mejora en tiempo de traslados, sino que también el costo de producción. Se realizaron una serie de pruebas en campo con el fin de comparar la funcionalidad, ventajas y desventajas sobre otros sistemas de detección ya creados, con la intención de alcanzar un control de tránsito más barato y eficiente.Consejo Nacional de Ciencia y Tecnologí

The IST Cluster: an integrated infrastructure for parallel applications in Physics and Engineering

WOS:000283531600008 (Nº de Acesso Web of Science)The infrastructure to support advanced computing applications at Instituto Superior T´ecnico is presented, including a detailed description of the hardware, system software, and benchmarks, which show an HPL performance of 1.6 Tflops. Due to its decentralized administrative basis, a discussion of the usage policy and administration is also given. The in-house codes running in production are also presented

Wigner function for twisted photons

A comprehensive theory of the Weyl-Wigner formalism for the canonical pair angle-angular momentum is presented, with special emphasis in the implications of rotational periodicity and angular-momentum discreteness.Comment: 6 pages, 4 figure