15,692 Hits in 1.3 sec

Helicobacter pylori y alteraciones endoscópicas en pacientes con obesidad severa, programados para cirugía bariátrica

William Otero Regino, Lina Otero, Alba Alicia Trespalacios
2016 Revista Colombiana de Gastroenterología  
Ninguno tuvo atrofia severa (OLGA III o IV). Conclusión: todos los pacientes tenían alguna alteración en la endoscopia. De estos, 2 pacientes tenían várices esofágicas.  ...  En los pacientes con obesidad severa, la única intervención terapéutica eficaz es la cirugía bariátrica y la más frecuentemente utilizada es el bypass gástrico con reconstrucción en "Y" de Roux (BPGYR)  ...  El tratamiento dietético y los ejercicios pueden inducir una pérdida de peso del 5%-10% en los pacientes con obesidad severa; cuando se logra este descenso, impacta favorablemente en las comorbilidades  ... 
doi:10.22516/25007440.36 fatcat:awp3kjavxzhy7oroxqif2rlvtq

Context-modulation of hippocampal dynamics and deep convolutional networks [article]

James B. Aimone, William M. Severa
2017 arXiv   pre-print
Complex architectures of biological neural circuits, such as parallel processing pathways, has been behaviorally implicated in many cognitive studies. However, the theoretical consequences of circuit complexity on neural computation have only been explored in limited cases. Here, we introduce a mechanism by which direct and indirect pathways from cortex to the CA3 region of the hippocampus can balance both contextual gating of memory formation and driving network activity. We implement this
more » ... ept in a deep artificial neural network by enabling a context-sensitive bias. The motivation for this is to improve performance of a size-constrained network. Using direct knowledge of the superclass information in the CIFAR-100 and Fashion-MNIST datasets, we show a dramatic increase in performance without an increase in network size.
arXiv:1711.09876v1 fatcat:gaa5ey6qqfgndfai7x6gvo7ote

Spiking Neural Algorithms for Markov Process Random Walk [article]

William Severa, Rich Lehoucq, Ojas Parekh, James B. Aimone
2018 arXiv   pre-print
The random walk is a fundamental stochastic process that underlies many numerical tasks in scientific computing applications. We consider here two neural algorithms that can be used to efficiently implement random walks on spiking neuromorphic hardware. The first method tracks the positions of individual walkers independently by using a modular code inspired by the grid cell spatial representation in the brain. The second method tracks the densities of random walkers at each spatial location
more » ... ectly. We analyze the scaling complexity of each of these methods and illustrate their ability to model random walkers under different probabilistic conditions.
arXiv:1805.00509v1 fatcat:ciwqtixhdvflvi6mcpzqjcznae

Geometric representation of the infimax S-adic family [article]

Philip Boyland, William Severa
2017 arXiv   pre-print
We construct geometric realizations for the infimax family of substitutions by generalizing the Rauzy-Canterini-Siegel method for a single substitution to the S-adic case. The composition of each countably infinite subcollection of substitutions from the family has an asymptotic fixed sequence whose shift orbit closure is an infimax minimal set Δ^+. The subcollection of substitutions also generates an infinite Bratteli-Vershik diagram with prefix-suffix labeled edges. Paths in the diagram give
more » ... he Dumont-Thomas expansion of sequences in Δ^+ which in turn gives a projection onto the asymptotic stable direction of the infinite product of the Abelianization matrices. The projections of all sequences from Δ^+ is the generalized Rauzy fractal which has subpieces corresponding to the images of symbolic cylinder sets. The intervals containing these subpieces are shown to be disjoint except at endpoints, and thus the induced map derived from the symbolic shift translates them. Therefore the process yields an Interval Translation Map, and the Rauzy fractal is proved to be its attractor.
arXiv:1603.09726v2 fatcat:3d7hujq7ejbgrlc4mnvdsrfksa

Utilización del índice de shock en el manejo de pacientes con sepsis severa y choque séptico: una revisión sistemática

Juan José Diaztagle Fernández, William Alexis Gómez Núñez, Merideidy Plazas Vargas
2016 Acta Colombiana de Cuidado Intensivo  
Objetivo: Determinar el uso y el impacto del IS en pacientes con sepsis severa y choque séptico.  ...  Palabras clave: Índice de shock, choque séptico, sepsis, sepsis severa, metas de reanimación.  ...  En Colombia, se ha documentado una mortalidad de 21.9 y 45.6% para sepsis severa y choque séptico respectivamente (3) .  ... 
doi:10.1016/j.acci.2016.08.005 fatcat:2zpanavfzfe2revwcr2ica7wfm

Abelian Square-Free Partial Words [chapter]

Francine Blanchet-Sadri, Jane I. Kim, Robert Mercaş, William Severa, Sean Simmons
2010 Lecture Notes in Computer Science  
Erdös raised the question whether there exist infinite abelian square-free words over a given alphabet (words in which no two adjacent subwords are permutations of each other). Infinite abelian square-free words have been constructed over alphabets of sizes as small as four. In this paper, we investigate the problem of avoiding abelian squares in partial words (sequences that may contain some holes). In particular, we give lower and upper bounds for the number of letters needed to construct
more » ... nite abelian square-free partial words with finitely or infinitely many holes. In the case of one hole, we prove that the minimal alphabet size is four, while in the case of more than one hole, we prove that it is five.
doi:10.1007/978-3-642-13089-2_8 fatcat:rq3duhwdwfefhdns37oivwckbq

Tratamento cirúrgico de fratura severa de ossos próprios do nariz: relato de caso

Gabriel Mulinari dos Santos, William Ricardo Pires, Leonardo Freitas Silva, Ciro Borges Duailibe de Deus, Gustavo Antonio Correa Momesso, Tárik Ocon Braga Polo, Francisley Ávila Souza, Idelmo Rangel Garcia Júnior, Leonardo Perez Faverani
As fraturas nasais são as fraturas mais frequentes em face, esse fato ocorre devido a proeminência dos ossos próprios do nariz (OPN) em relação a face, que faz com que eles possam receber o primeiro impacto frente a um trauma. As fraturas nasais (FN) podem ter seu tratamento cirúrgico ou não, de acordo com a condição estética e também funcional do paciente. O presente trabalho tem como objetivo relatar um caso clínico de um paciente de 30 anos, sexo masculino, leucoderma, vítima de agressão
more » ... ca, admitido na Santa Casa de Misericórdia de Araçatuba relatando sangramento nasal abundante, dificuldade respiratória e dor em face. Ao exame clínico notou-se rinoescoliose significativa á direita e impermeabilidade das vias aéreas, e no exame de imagem por tomografia computadorizada observou fratura OPN envolvendo fratura e desvio de septo nasal. Pelas condições apresentadas no exame clínico e de imagem, foi proposto tratamento cirúrgico sob anestesia geral. A primeira etapa cirúrgica foi realizada com reposição dos fragmentos, seguida do tamponamento para sustentação com tamponamento, porém sem sucesso estéticos e funcionais. A segunda etapa cirúrgica foi realizada sob anestesia geral, com redução da fratura, do desvio de septo e tamponamento. No pós-operatório foi possível notar um resultado satisfatório funcional com patência das vias aéreas e também estético, quando comparado com imagens fotográficas do paciente prévias ao trauma.Descritores: Fraturas Ósseas; Fixação de Fratura; Traumatismos Faciais.
doi:10.21270/archi.v6i4.2054 fatcat:6ja6kr6a5rgsdhwxgtyt2uq2b4

Data-driven Feature Sampling for Deep Hyperspectral Classification and Segmentation [article]

William M. Severa, Jerilyn A. Timlin, Suraj Kholwadwala, Conrad D. James, James B. Aimone
2017 arXiv   pre-print
The high dimensionality of hyperspectral imaging forces unique challenges in scope, size and processing requirements. Motivated by the potential for an in-the-field cell sorting detector, we examine a Synechocystis sp. PCC 6803 dataset wherein cells are grown alternatively in nitrogen rich or deplete cultures. We use deep learning techniques to both successfully classify cells and generate a mask segmenting the cells/condition from the background. Further, we use the classification accuracy to
more » ... uide a data-driven, iterative feature selection method, allowing the design neural networks requiring 90 fewer input features with little accuracy degradation.
arXiv:1710.09934v1 fatcat:2hazypy6svfjjpssvd5opxqdka

A Combinatorial Model for Dentate Gyrus Sparse Coding

William Severa, Ojas Parekh, Conrad D. James, James B. Aimone
2017 Neural Computation  
The dentate gyrus forms a critical link between the entorhinal cortex and CA3 by providing a sparse version of the signal. Concurrent with this increase in sparsity, a widely accepted theory suggests the dentate gyrus performs pattern separation-similar inputs yield decorrelated outputs. Although an active region of study and theory, few logically rigorous arguments detail the dentate gyrus's (DG) coding. We suggest a theoretically tractable, combinatorial model for this action. The model
more » ... es formal methods for a highly redundant, arbitrarily sparse, and decorrelated output signal. To explore the value of this model framework, we assess how suitable it is for two notable aspects of DG coding: how it can handle the highly structured grid cell representation in the input entorhinal cortex region and the presence of adult neurogenesis, which has been proposed to produce a heterogeneous code in the DG. We find tailoring the model to grid cell input yields expansion parameters consistent with the literature. In addition, the heterogeneous coding reflects activity gradation observed experimentally. Finally, we connect this approach with more conventional binary threshold neural circuit models via a formal embedding.
doi:10.1162/neco_a_00905 pmid:27764589 fatcat:c4me64kq3zan5nlgknwb3jfoby

Making BREAD: Biomimetic strategies for Artificial Intelligence Now and in the Future [article]

Jeffrey L. Krichmar, William Severa, Salar M. Khan, James L. Olds
2018 arXiv   pre-print
The Artificial Intelligence (AI) revolution foretold of during the 1960s is well underway in the second decade of the 21st century. Its period of phenomenal growth likely lies ahead. Still, we believe, there are crucial lessons that biology can offer that will enable a prosperous future for AI. For machines in general, and for AI's especially, operating over extended periods or in extreme environments will require energy usage orders of magnitudes more efficient than exists today. In many
more » ... ional environments, energy sources will be constrained. Any plans for AI devices operating in a challenging environment must begin with the question of how they are powered, where fuel is located, how energy is stored and made available to the machine, and how long the machine can operate on specific energy units. Hence, the materials and technologies that provide the needed energy represent a critical challenge towards future use-scenarios of AI and should be integrated into their design. Here we make four recommendations for stakeholders and especially decision makers to facilitate a successful trajectory for this technology. First, that scientific societies and governments coordinate Biomimetic Research for Energy-efficient, AI Designs (BREAD); a multinational initiative and a funding strategy for investments in the future integrated design of energetics into AI. Second, that biomimetic energetic solutions be central to design consideration for future AI. Third, that a pre-competitive space be organized between stakeholder partners and fourth, that a trainee pipeline be established to ensure the human capital required for success in this area.
arXiv:1812.01184v1 fatcat:w4q74adi6rgpfheq44ex2pyxcu

Neuromorphic scaling advantages for energy-efficient random walk computation [article]

J. Darby Smith, Aaron J. Hill, Leah E. Reeder, Brian C. Franke, Richard B. Lehoucq, Ojas Parekh, William Severa, James B. Aimone
2021 arXiv   pre-print
Computing stands to be radically improved by neuromorphic computing (NMC) approaches inspired by the brain's incredible efficiency and capabilities. Most NMC research, which aims to replicate the brain's computational structure and architecture in man-made hardware, has focused on artificial intelligence; however, less explored is whether this brain-inspired hardware can provide value beyond cognitive tasks. We demonstrate that high-degree parallelism and configurability of spiking neuromorphic
more » ... architectures makes them well-suited to implement random walks via discrete time Markov chains. Such random walks are useful in Monte Carlo methods, which represent a fundamental computational tool for solving a wide range of numerical computing tasks. Additionally, we show how the mathematical basis for a probabilistic solution involving a class of stochastic differential equations can leverage those simulations to provide solutions for a range of broadly applicable computational tasks. Despite being in an early development stage, we find that NMC platforms, at a sufficient scale, can drastically reduce the energy demands of high-performance computing (HPC) platforms.
arXiv:2107.13057v1 fatcat:6saeb5a4jrhqto5scokhg4x4zq

Making BREAD: Biomimetic Strategies for Artificial Intelligence Now and in the Future

Jeffrey L. Krichmar, William Severa, Muhammad S. Khan, James L. Olds
2019 Frontiers in Neuroscience  
., 2017; Severa et al., 2019) , we recognize that these methods do not address the full needs of future applications, despite offering compelling first steps.  ...  See Diamond et al. (2016), Severa et al. (2019), Hunsberger and Eliasmith (2016), Disney et al. (2016), Davison et al. (2009), Ehsan et al. (2017), and Wolfe et al. ( FIGURE 2 | 2 Various neuromorphic  ...  Copyright © 2019 Krichmar, Severa, Khan and Olds. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).  ... 
doi:10.3389/fnins.2019.00666 pmid:31316340 pmcid:PMC6610536 fatcat:y7o5adft3vevppbf3d2rqolvqm

Avoiding abelian squares in partial words

F. Blanchet-Sadri, Jane I. Kim, Robert Mercaş, William Severa, Sean Simmons, Dimin Xu
2012 Journal of combinatorial theory. Series A  
Erdős raised the question whether there exist infinite abelian square-free words over a given alphabet, that is, words in which no two adjacent subwords are permutations of each other. It can easily be checked that no such word exists over a three-letter alphabet. However, infinite abelian square-free words have been constructed over alphabets of sizes as small as four. In this paper, we investigate the problem of avoiding abelian squares in partial words, or sequences that may contain some
more » ... s. In particular, we give lower and upper bounds for the number of letters needed to construct infinite abelian square-free partial words with finitely or infinitely many holes. Several of our constructions are based on iterating morphisms. In the case of one hole, we prove that the minimal alphabet size is four, while in the case of more than one hole, we prove that it is five. We also investigate the number of partial words of length n with a fixed number of holes over a five-letter alphabet that avoid abelian squares and show that this number grows exponentially with n.
doi:10.1016/j.jcta.2011.08.008 fatcat:5sarssevh5ao3iv2mcyriurudq

Evaluating complexity and resilience trade-offs in emerging memory inference machines [article]

Christopher H. Bennett, Ryan Dellana, T. Patrick Xiao, Ben Feinberg, Sapan Agarwal, Suma Cardwell, Matthew J. Marinella, William Severa, Brad Aimone
2020 arXiv   pre-print
Neuromorphic-style inference only works well if limited hardware resources are maximized properly, e.g. accuracy continues to scale with parameters and complexity in the face of potential disturbance. In this work, we use realistic crossbar simulations to highlight that compact implementations of deep neural networks are unexpectedly susceptible to collapse from multiple system disturbances. Our work proposes a middle path towards high performance and strong resilience utilizing the Mosaics
more » ... ework, and specifically by re-using synaptic connections in a recurrent neural network implementation that possesses a natural form of noise-immunity.
arXiv:2003.10396v1 fatcat:ehqfnisp75frlfvur2zrtyzvpa

Solving a steady-state PDE using spiking networks and neuromorphic hardware [article]

J. Darby Smith, William Severa, Aaron J. Hill, Leah Reeder, Brian Franke, Richard B. Lehoucq, Ojas D. Parekh, James B. Aimone
2020 arXiv   pre-print
The widely parallel, spiking neural networks of neuromorphic processors can enable computationally powerful formulations. While recent interest has focused on primarily machine learning tasks, the space of appropriate applications is wide and continually expanding. Here, we leverage the parallel and event-driven structure to solve a steady state heat equation using a random walk method. The random walk can be executed fully within a spiking neural network using stochastic neuron behavior, and
more » ... provide results from both IBM TrueNorth and Intel Loihi implementations. Additionally, we position this algorithm as a potential scalable benchmark for neuromorphic systems.
arXiv:2005.10904v1 fatcat:oglbktiqa5burdeaoc5s7q5zeq
« Previous Showing results 1 — 15 out of 15,692 results