1,181 research outputs found

    High dose multiple micronutrient supplementation improves villous morphology in environmental enteropathy without HIV enteropathy: results from a double-blind randomised placebo controlled trial in Zambian adults

    Get PDF
    PMCID: PMC3897937This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

    A Comparative Study of Reservoir Computing for Temporal Signal Processing

    Get PDF
    Reservoir computing (RC) is a novel approach to time series prediction using recurrent neural networks. In RC, an input signal perturbs the intrinsic dynamics of a medium called a reservoir. A readout layer is then trained to reconstruct a target output from the reservoir's state. The multitude of RC architectures and evaluation metrics poses a challenge to both practitioners and theorists who study the task-solving performance and computational power of RC. In addition, in contrast to traditional computation models, the reservoir is a dynamical system in which computation and memory are inseparable, and therefore hard to analyze. Here, we compare echo state networks (ESN), a popular RC architecture, with tapped-delay lines (DL) and nonlinear autoregressive exogenous (NARX) networks, which we use to model systems with limited computation and limited memory respectively. We compare the performance of the three systems while computing three common benchmark time series: H{\'e}non Map, NARMA10, and NARMA20. We find that the role of the reservoir in the reservoir computing paradigm goes beyond providing a memory of the past inputs. The DL and the NARX network have higher memorization capability, but fall short of the generalization power of the ESN

    Estudio geofísico de la corteza oceánica de la Cuenca Canaria (Atlántico Centro-Oriental)

    Get PDF
    [ES] El estudio combinado de datos de sísmica de reflexión de multicanal y de monocanal permite conocer la estructura de la corteza oceánica de la Cuenca Canaria y relacionarla con la historia de la expansión del fondo oceánico y las principales estructuras tectónicas formadas durante el Mesozoico en el Atlántico Central.[EN] The combined study of single and multi-channel seismic reflection data allow us to understand the structure of the Canary Basin oceanic crust and their relationship with the seafloor spreading history and main tectonic features formed during Mesozoic times on the Central Atlantic.Este trabajo es parte del estudio llevado a cabo por C.R. Ranero, bajo la dirección de E Banda, en el Instituto de Ciencias de la Tierra "Jaume Almera" del CSIC para la obtención del grado de Doctor. C.R. Ranero recibió financiación durante su estancia en el Instituto de Ciencias de la Tierra mediante unsi beca de "Formació d'Investigadors de el "Departament d'Ensenyament de la Generalitat de Catalunya".Peer reviewe

    A knowledge-based expert system for scheduling of airborne astronomical observations

    Get PDF
    The Kuiper Airborne Observatory Scheduler (KAOS) is a knowledge-based expert system developed at NASA Ames Research Center to assist in route planning of a C-141 flying astronomical observatory. This program determines a sequence of flight legs that enables sequential observations of a set of heavenly bodies derived from a list of desirable objects. The possible flight legs are constrained by problems of observability, avoiding flyovers of warning and restricted military zones, and running out of fuel. A significant contribution of the KAOS program is that it couples computational capability with a reasoning system

    HIV infection and domestic smoke exposure, but not human papillomavirus, are risk factors for esophageal squamous cell carcinoma in Zambia: a case-control study

    Get PDF
    (c) 2015 The Authors. Cancer Medicine published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

    Mechanism of salinity change and hydrogeochemical evolution of groundwater in the Machile-Zambezi Basin, South-western Zambia

    Get PDF
    Machile-Zambezi Basin, South-Western Zambia hosts high salinity groundwater which threatens water security for rural inhabitants. This study investigates the hydrological mechanism that led to high salinity and the geochemical evolution of the groundwater system. The Machile-Zambezi Basin is part of the wider Kalahari Basin which underwent major palaeo-environmental climatic, tectonic and sedimentology dynamics which must have impacted the groundwater salinity. The study examines the groundwater level, hydrochemistry, environmental isotopes (18O/16O, 2H/1H, 3H/3He, 14C/13C). In addition, the sediment cation exchange capacity (CEC) and pore-water chemistry on intact core material were measured. The groundwater chemistry evolved from fresh Ca(Na)HCO3 to saline Na(Ca, Mg)SO4 due to dissolution of salts and not evaporation as indicated by stable isotopes. The saline groundwater is old with 14C ages estimates of more than 1000 years old and stagnant. Geochemical modelling using PHREEQC suggests that ionic exchange due to release of cations from dissolving salts and sulphate reduction were also important processes in this system. High groundwater salinity is therefore associated with Pre-Holocene environmental changes and is restricted to a stagnant saline zone. It will therefore remain unflushed as long as current climatic conditions remain

    Ultrasound potentialities on the determination of the pesticide carbaryl using diamond electrodes

    Get PDF
    The potentiality of the use of ultrasound radiation in association with a boron-doped diamond electrode was evaluated on the voltammetric determination of the pesticide carbaryl. Improvements in the sensitivity, limit of detection and reproducibility of the measurements were observed due to both, the enhancement of mass transport and the cleaning of the electrode surface provided by ultrasound. Satisfactory recovery levels for carbaryl in pure water (96-98%) and pineapple juice (89-92%) for quiescent and sonovoltammetric methodologies were obtained. These methodologies can be alternative tools for the analyses of pesticides in fruit samples, mainly the insonated condition that improve the analytical performance and dispense intermediary cleanings of the electrode surface.CNPqFapes

    Language policy and orthographic harmonization across linguistic, ethnic and national boundaries in Southern Africa

    Get PDF
    Drawing on online and daily newspapers, speakers' language and writing practices, official government documents and prescribed spelling systems in Southern Africa, the paper explores the challenges and possibilities of orthographic reforms allowing for mobility across language clusters, ethnicity, regional and national borders. I argue that this entails a different theorisation of language, and for orthographies that account for the translocations and diasporic nature of late modern African identities and lifestyles. I suggest an ideological shift from prescriptivism to practice-orientated approaches to harmonisation in which orthographies are based on descriptions of observable writing practices in the mobile linguistic universe. The argument for orthographic reforms is counterbalanced with an expose on current language policies which appear designed for an increasing rare monoglot 'standard' speaker, who speaks only a 'tribal' language. The implications of the philosophical challenges this poses for linguists, language planners and policy makers are thereafter discussed.IS

    Determination of 5-aminosalicylic acid in pharmaceutical formulations by square wave voltammetry at pencil graphite electrodes

    Get PDF
    An analytical method for the determination of the anti-inflammatory drug 5-aminosalicylic acid (5-ASA) in pharmaceutical formulations using square wave voltammetry at pencil graphite electrodes was developed. After the optimization of the experimental conditions, calibration curves were obtained in the linear concentration range from 9.78 × 10-7 to 7.25 × 10-5 mol L-1 resulting in a limit of detection of 2.12 ± 0.05 x 10-8 mol L-1. Statistical tests showed that the concentrations of 5-ASA in commercial tablets and enemas obtained with the proposed voltammetric method agreed with HPLC values at a 95% confidence level.CNPqFAPES
    corecore