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
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
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)
[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
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
(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
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
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
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
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
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