Transcranial ultrasound simulation with uncertainty estimation

Transcranial ultrasound simulations are increasingly used to predict in situ exposure parameters for ultrasound therapies in the brain. However, there can be considerable uncertainty in estimating the acoustic medium properties of the skull and brain from computed tomography (CT) images. This paper shows how the resulting uncertainty in the simulated acoustic field can be predicted in a computationally efficient way using linear uncertainty propagation. Results for a representative transcranial simulation using a focused bowl transducer at 500 kHz show good agreement with unbiased uncertainty estimates obtained using Monte Carlo

Propuesta de mejoramiento organizacional de la empresa Indumetálicas M&G de la ciudad de Tunja

Organigrama, matriz dofaLa estructura organizacional es la herramienta que se encarga de definir las funciones que se deben realizar y quienes las realizan. Algunas de las funciones de esta herramienta son establecer autoridad, jerarquía, cadena de mando, organigramas, departamentalizaciones, etc. Teniendo en cuenta que INDUMETÁLICAS M&G presenta dificultades organizacionales y que toda compañía requiere de una buena estructura organizacional, este trabajo tuvo como objetivo principal diseñar una estructura organizacional a la empresa INDUMETÁLICAS M&G para el mejoramiento de sus procesos. Para cumplir con dicho objetivo se realizó inicialmente un diagnóstico de la estructura organizacional de la empresa mediante observación, registro fotográfico, documentación de la empresa y la información recolectada a través de una entrevista realizada al gerente sobre las generalidades y situación actual de la empresa. Además, se realizó una encuesta a tres trabajadores del área administrativa y cuatro del área productiva para identificar que tanto conocían sobre el estado organizacional de la empresa. Posteriormente, se realizó la identificación de las amenazas, debilidades, fortalezas y oportunidades analizando la información recolectada mediante la observación, la encuesta, la entrevista y usando la matriz DOFA. Finalmente, se propuso un plan de mejoramiento organizacional para INDUMETÁLICAS M&G. Los principales resultados obtenidos fueron lograr la descripción de las cargas laborales de cada uno de los funcionarios de la empresa, la construcción el organigrama con base a los cargos que existen actualmente y los que se proponen crear, la identificación de aspectos por mejorar en la estructura organizacional, así como el desarrollo del plan de mejoramiento

"Les caraïbes n'étaient pas si mauvais cuisiniers que je me l'imaginais" : alimentación en el Caribe en el siglo XVIII según viajeros

RESUMEN: El exuberante Caribe fue el foco de interés de gran cantidad de viajeros europeos durante el Siglo XVIII, que llegaban con la nueva mentalidad de estudiar toda la riqueza natural y el estado político, económico y social de las poblaciones que lo habitaban. La alimentación fue uno de los ejes fundamentales del acercamiento a lo extraño por parte de estos viajeros; plasmaron en sus relatos un sinnúmero de referencias sobre productos alimenticios, platos, bebidas, cultivos, entre otros. Este trabajo presenta y analiza bebidas, productos, platos, preparaciones, que se encontraron en los escritos de algunos viajeros que visitaron el Caribe; permitiendo observar nuevos comestibles y víveres, nuevas maneras de ingestión, sustituciones de productos y platos, diferenciación de consumo, todos ellos generados por los contactos culturales, reconocimiento y diferenciación del otro. Así mismo, teniendo en cuenta las creencias y teorías dietéticas de la época, se trata de dar un poco de luz sobre la posible calificación por parte de los europeos como “salvajes” a los habitantes caribeños según sus hábitos alimenticios.ABSTRACT: The exuberant Caribbean was a focus of interest for many European travelers during the eighteenth century, who traveled with the new mentality of studying its natural wealth as well as the political, economic and social status of its inhabitants. Food was a fundamental way for these travelers to approach the unknown, using in their stories a number of references on food products, dishes, drinks, crops, among others. This study presents and analyzes beverages, products, dishes and preparations which were found in the writings of some travelers who arrived in the Caribbean; allowing us to find new edibles and provisions, new ways of food intake, substitutions of products and dishes, and differentiations in consumption; all of these generated by cultural contacts, recognition and differentiation of the other. Likewise, taking into account the dietary beliefs and theories of the time, we attempt to put a spotlight on whether Europeans would label Caribbean inhabitants as “salvajes” depending on their eating habits

Genetic and pharmacological inhibition of calcineurin corrects the BDNF transport defect in Huntington's disease

<p>Abstract</p> <p>Background</p> <p>Huntington's disease (HD) is an inherited neurogenerative disease caused by an abnormal expansion of glutamine repeats in the huntingtin protein. There is currently no treatment to prevent the neurodegeneration caused by this devastating disorder. Huntingtin has been shown to be a positive regulator of vesicular transport, particularly for neurotrophins such as brain-derived neurotrophic factor (BDNF). This function is lost in patients with HD, resulting in a decrease in neurotrophic support and subsequent neuronal death. One promising line of treatment is therefore the restoration of huntingtin function in BDNF transport.</p> <p>Results</p> <p>The phosphorylation of huntingtin at serine 421 (S421) restores its function in axonal transport. We therefore investigated whether inhibition of calcineurin, the <it>bona fide </it>huntingtin S421 phosphatase, restored the transport defects observed in HD. We found that pharmacological inhibition of calcineurin by FK506 led to sustained phosphorylation of mutant huntingtin at S421. FK506 restored BDNF transport in two complementary models: rat primary neuronal cultures expressing mutant huntingtin and mouse cortical neurons from <it>Hdh</it>^Q111/Q111HD knock-in mice. This effect was the result of specific calcineurin inhibition, as calcineurin silencing restored both anterograde and retrograde transport in neurons from <it>Hdh</it>^Q111/Q111mice. We also observed a specific increase in calcineurin activity in the brain of <it>Hdh</it>^Q111/Q111mice potentially accounting for the selective loss of huntingtin phosphorylation and contributing to neuronal cell death in HD.</p> <p>Conclusion</p> <p>Our results validate calcineurin as a target for the treatment of HD and provide the first demonstration of the restoration of huntingtin function by an FDA-approved compound.</p

Functional brain networks: great expectations, hard times and the big leap forward

Many physical and biological systems can be studied using complex network theory, a new statistical physics understanding of graph theory. The recent application of complex network theory to the study of functional brain networks has generated great enthusiasm as it allows addressing hitherto non-standard issues in the field, such as efficiency of brain functioning or vulnerability to damage. However, in spite of its high degree of generality, the theory was originally designed to describe systems profoundly different from the brain. We discuss some important caveats in the wholesale application of existing tools and concepts to a field they were not originally designed to describe. At the same time, we argue that complex network theory has not yet been taken full advantage of, as many of its important aspects are yet to make their appearance in the neuroscience literature. Finally, we propose that, rather than simply borrowing from an existing theory, functional neural networks can inspire a fundamental reformulation of complex network theory, to account for its exquisitely complex functioning mode

Olfactory fMRI Connectivity Analysis Based on Granger Causality with Application in Anosmia Assessment

In this work, we describe hubs organization within the olfactory network with Functional Magnetic Resonance Imaging (fMRI). Granger causality analyses were applied in the supposed regions of interest (ROIs) involved in olfactory tasks, as described in [1]. We aim to get deeper knowledge about the hierarchy of the regions within the olfactory network and to describe which of these regions, in terms of strength of the connectivity, impair in different types of anosmia

Classical and learned MR to pseudo-CT mappings for accurate transcranial ultrasound simulation

Model-based treatment planning for transcranial ultrasound therapy typically involves mapping the acoustic properties of the skull from an x-ray computed tomography (CT) image of the head. Here, three methods for generating pseudo-CT images from magnetic resonance (MR) images were compared as an alternative to CT. A convolutional neural network (U-Net) was trained on paired MR-CT images to generate pseudo-CT images from either T1-weighted or zero-echo time (ZTE) MR images (denoted tCT and zCT, respectively). A direct mapping from ZTE to pseudo-CT was also implemented (denoted cCT). When comparing the pseudo-CT and ground truth CT images for the test set, the mean absolute error was 133, 83, and 145 Hounsfield units (HU) across the whole head, and 398, 222, and 336 HU within the skull for the tCT, zCT, and cCT images, respectively. Ultrasound simulations were also performed using the generated pseudo-CT images and compared to simulations based on CT. An annular array transducer was used targeting the visual or motor cortex. The mean differences in the simulated focal pressure, focal position, and focal volume were 9.9%, 1.5 mm, and 15.1% for simulations based on the tCT images, 5.7%, 0.6 mm, and 5.7% for the zCT, and 6.7%, 0.9 mm, and 12.1% for the cCT. The improved results for images mapped from ZTE highlight the advantage of using imaging sequences which improve contrast of the skull bone. Overall, these results demonstrate that acoustic simulations based on MR images can give comparable accuracy to those based on CT

Functional Brain Networks: beyond the small-world paradigm

This contribution reviews the current state of art comprising the application of Complex Networks Theory to the analysis of functional brain networks. We briefly overview the main advances in this field during the last decade and we explain how graph analysis has increased our knowledge about how the brain behaves when performing a specific task or how it fails when a certain pathology arises. We also show the limitations of this kind of analysis, which have been a source of confusion and misunderstanding when interpreting the results obtained. Finally, we discuss about a possible direction to follow in the next years

Defender el estado : quince años de suplicios tres eventos significativos en el régimen penal colombiano entre 1971 y 1986

Este artículo de investigación pretende hacer una lectura de la historia del derecho penal colombiano en el periodo que va de 1971 a 1986. Para el efecto se han identificado tres eventos significativos que dan cuenta de la dinámica del discurso penal durante la época estudiada: el cierre de la Colonia Penal de Araracuara, la expedición del Estatuto de Seguridad y la expedición del Código Penal de 1980. De esta manera, este ensayo pretende demostrar que la continuidad en las prácticas supliciantes -torturas, desapariciones, ejecuciones extrajudiciales, entre otros- que se evidencian con el recuento de los tres eventos significativos antes señalados obedece al mantenimiento de una misma razón de Estado que permeó en el funcionamiento del régimen penal durante la época estudiada, en el marco de la producción permanente de un derecho penal de enemigo. Este documento pretende hacer explícito el lugar que toma la dinámica de la razón de Estado en el funcionamiento del sistema penal y del discurso profundo que lo inspira. Finalmente el trabajo concluye con un análisis del papel del discurso de los derechos humanos al interior de la dinámica de la razón de Estado con fin de demostrar la existencia de una tensión discursiva presente en el manejo que se le da al discurso de los derechos humanos tanto por parte de las organizaciones internacionales protectoras de los derechos humanos como por parte del Estado.This research article aims to perform a reading of the history of Colombian criminal law regarding the period between 1971 a 1986. For that matter three significant events have been identified which concern the dynamics of the criminal discourse during this time: the closure of the Criminal Colony of Araracuara, the issuing of the Security Statute and the issuing of the Criminal Code of 1980. Therefore, this investigation seeks to prove that the continuousness of supplice practices -torture, disappearances, extrajudicial executions- throughout this period is due to the uninterruptedness of the same raison d?fitat that permeated the functioning of the corresponding criminal regime within the framework of a permanent output of a criminal law for the enemy. This document means to make explicit the place that this raison d?fitat dynamic takes in the functioning of the criminal system and the profound discourse that inspires it. Finally, this paper concludes with an analysis of the role of human rights within the dynamics of the raison d?£tat in order to prove the existence of a discursive tension present in the handling of the human rights discourse issued both by human rights international organizations as well as by the State of Colombia.Abogado (a)Pregrad