87 research outputs found
Learning-based Observer Evaluated on the Kinematic Bicycle Model
The knowledge of the states of a vehicle is a necessity to perform proper
planning and control. These quantities are usually accessible through
measurements. Control theory brings extremely useful methods -- observers -- to
deal with quantities that cannot be directly measured or with noisy
measurements. Classical observers are mathematically derived from models. In
spite of their success, such as the Kalman filter, they show their limits when
systems display high non-linearities, modeling errors, high uncertainties or
difficult interactions with the environment (e.g. road contact). In this work,
we present a method to build a learning-based observer able to outperform
classical observing methods. We compare several neural network architectures
and define the data generation procedure used to train them. The method is
evaluated on a kinematic bicycle model which allows to easily generate data for
training and testing. This model is also used in an Extended Kalman Filter
(EKF) for comparison of the learning-based observer with a state of the art
model-based observer. The results prove the interest of our approach and pave
the way for future improvements of the technique.Comment: ICSC 202
Robust LSTM-based Vehicle Velocity Observer for Regular and Near-limits Applications
Accurate velocity estimation is key to vehicle control. While the literature
describes how model-based and learning-based observers are able to estimate a
vehicle's velocity in normal driving conditions, the challenge remains to
estimate the velocity in near-limits maneuvers while using only conventional
in-car sensors. In this paper, we introduce a novel neural network architecture
based on Long Short-Term Memory (LSTM) networks to accurately estimate the
vehicle's velocity in different driving conditions, including maneuvers at the
limits of handling. The approach has been tested on real vehicle data and it
provides more accurate estimations than state-of-the-art model-based and
learning-based methods, for both regular and near-limits driving scenarios. Our
approach is robust since the performance of the state-of-the-art observers
deteriorates with higher dynamics, while our method adapts to different
maneuvers, providing accurate estimations even at the vehicle's limits of
handling
Community Mortality due to Respiratory Syncytial Virus in Argentina: Population-based surveillance study
Background. Many deaths in infants from low-middle income countries (LMICs) occur at home or upon arrival to health facilities. Although acute lower respiratory tract illness plays an important role in community mortality, the accuracy of mortality rates due to respiratory syncytial virus (RSV) remains unknown.
Methods. An active surveillance study among children aged under 5 years old (U5) was performed in Buenos Aires, Argentina, between January and December 2019, to define the burden and role of RSV in childhood community mortality.
Results. A total of 63 families of children U5 participated in the study. Based on a combined approach of tissue sampling, verbal autopsies, and expert’s analysis, RSV infection was found in the causal chain of 11 from 12 cases with positive molecular biology results in respiratory samples. The estimated mortality rate due to RSV among infants was 0.27 deaths/1000 live births. The mean age of RSV-related household deaths was 2.8 months of age (standard deviation [SD] 1.7), and 8/12 were male infants (66.7%). Dying at home from RSV was associated with Streptococcus pneumoniae and/or Moraxella catarrhalis lung coinfection (75%), living in slums and settlement (odds ratio [OR], 17.09; 95% confidence interval [CI], 1.3–219.2), and other underlying comorbidities (OR, 14.87; 95% CI, 1.3–164.6).
Conclusions. Infant community mortality rates due to RSV are higher than those reported in industrialized countries and similar to those reported in hospital-based studies in the same catchment population.Fil: Caballero, Mauricio Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Bianchi, Alejandra Silvina. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Diaz Grigaites, Sebastian. Gobierno de la Provincia de Buenos Aires. Ministerio Publico. Ministerio Publico Fiscal. Instituto de Ciencias Forenses de Lomas de Zamora.; ArgentinaFil: de la Iglesia Niveyro, Paola Ximena. Hospital Italiano; ArgentinaFil: Nuño, Alejandra. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Valle, Sandra. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Afarian, Gabriela. Gobierno de la Provincia de Buenos Aires. Ministerio Publico. Ministerio Publico Fiscal. Instituto de Ciencias Forenses de Lomas de Zamora.; ArgentinaFil: Esperante, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Ferreti, Adrián. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Jares Baglivo, Sofía. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: De Luca, Julián. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Álvarez Paggi, Damián Jorge. Comisión Nacional de Investigación Científica y Tecnológica; Chile. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Diamanti, Adriana. Gobierno de la Provincia de Buenos Aires. Ministerio Publico. Ministerio Publico Fiscal. Instituto de Ciencias Forenses de Lomas de Zamora.; ArgentinaFil: Bassat, Quique. Universidad de Barcelona; España. Centro de investigação de Saúde de Manhiça; Mozambique. Institució Catalana de Recerca i Estudis Avancats; España. Hospital Sant Joan de Deu Barcelona; España. Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública; EspañaFil: Polack, Fernando Pedro. Fundación para la Investigación en Infectología Infantil; Argentin
Causal hierarchy within the thalamo-cortical network in spike and wave discharges
Background: Generalised spike wave (GSW) discharges are the electroencephalographic (EEG) hallmark of absence seizures, clinically characterised by a transitory interruption of ongoing activities and impaired consciousness, occurring during states of reduced awareness. Several theories have been proposed to explain the pathophysiology of GSW discharges and the role of thalamus and cortex as generators. In this work we extend the existing theories by hypothesizing a role for the precuneus, a brain region neglected in previous works on GSW generation but already known to be linked to consciousness and awareness. We analysed fMRI data using dynamic causal modelling (DCM) to investigate the effective connectivity between precuneus, thalamus and prefrontal cortex in patients with GSW discharges. Methodology and Principal Findings: We analysed fMRI data from seven patients affected by Idiopathic Generalized Epilepsy (IGE) with frequent GSW discharges and significant GSW-correlated haemodynamic signal changes in the thalamus, the prefrontal cortex and the precuneus. Using DCM we assessed their effective connectivity, i.e. which region drives another region. Three dynamic causal models were constructed: GSW was modelled as autonomous input to the thalamus (model A), ventromedial prefrontal cortex (model B), and precuneus (model C). Bayesian model comparison revealed Model C (GSW as autonomous input to precuneus), to be the best in 5 patients while model A prevailed in two cases. At the group level model C dominated and at the population-level the p value of model C was ∼1. Conclusion: Our results provide strong evidence that activity in the precuneus gates GSW discharges in the thalamo-(fronto) cortical network. This study is the first demonstration of a causal link between haemodynamic changes in the precuneus - an index of awareness - and the occurrence of pathological discharges in epilepsy. © 2009 Vaudano et al
Vitamin E deficiency and risk of equine motor neuron disease
© 2007 Mohammed et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Mass Treatment with Azithromycin for Trachoma Control: Participation Clusters in Households
Trachoma, an infectious disease, continues to cause blindness. A great deal of the trachoma burden is concentrated in developing countries. The World Health Organization recommends mass treatment for entire communities in trachoma-endemic regions. In 32 Tanzanian and 48 Gambian communities with trachoma, mass treatment was directly observed following a census. Community coverage was mostly greater than 80%. Larger-than-expected proportions of households where all children were treated and where none of the children were treated were found in each country. Household clustering of treatment was higher in Tanzania compared to The Gambia. However, children who were not treated were not more likely to be infected compared to children who were treated. We found that treatment and non-treatment within communities does not occur at random but rather clusters within households. These findings impact the design of future coverage surveys and suggest that further research evaluate factors that are associated with familial non-compliance
Neglected Tropical Diseases in Sub-Saharan Africa: Review of Their Prevalence, Distribution, and Disease Burden
The neglected tropical diseases (NTDs) are the most common conditions affecting the poorest 500 million people living in sub-Saharan Africa (SSA), and together produce a burden of disease that may be equivalent to up to one-half of SSA's malaria disease burden and more than double that caused by tuberculosis. Approximately 85% of the NTD disease burden results from helminth infections. Hookworm infection occurs in almost half of SSA's poorest people, including 40–50 million school-aged children and 7 million pregnant women in whom it is a leading cause of anemia. Schistosomiasis is the second most prevalent NTD after hookworm (192 million cases), accounting for 93% of the world's number of cases and possibly associated with increased horizontal transmission of HIV/AIDS. Lymphatic filariasis (46–51 million cases) and onchocerciasis (37 million cases) are also widespread in SSA, each disease representing a significant cause of disability and reduction in the region's agricultural productivity. There is a dearth of information on Africa's non-helminth NTDs. The protozoan infections, human African trypanosomiasis and visceral leishmaniasis, affect almost 100,000 people, primarily in areas of conflict in SSA where they cause high mortality, and where trachoma is the most prevalent bacterial NTD (30 million cases). However, there are little or no data on some very important protozoan infections, e.g., amebiasis and toxoplasmosis; bacterial infections, e.g., typhoid fever and non-typhoidal salmonellosis, the tick-borne bacterial zoonoses, and non-tuberculosis mycobaterial infections; and arboviral infections. Thus, the overall burden of Africa's NTDs may be severely underestimated. A full assessment is an important step for disease control priorities, particularly in Nigeria and the Democratic Republic of Congo, where the greatest number of NTDs may occur
Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites
The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions.
The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness
of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence
were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density
and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that
the wood in the starch composites did not prevent water loss from the samples.Peer reviewe
Mapping of schistosomiasis and soil-transmitted helminths in Namibia: The first large-scale protocol to formally include rapid diagnostic tests
Background: Namibia is now ready to begin mass drug administration of praziquantel and albendazole against schistosomiasis and soil-transmitted helminths, respectively. Although historical data identifies areas of transmission of these neglected tropical diseases (NTDs), there is a need to update epidemiological data. For this reason, Namibia adopted a new protocol for mapping of schistosomiasis and geohelminths, formally integrating rapid diagnostic tests (RDTs) for infections and morbidity. In this article, we explain the protocol in detail, and introduce the concept of 'mapping resolution', as well as present results and treatment recommendations for northern Namibia.Methods/Findings/Interpretation: This new protocol allowed a large sample to be surveyed (N = 17 896 children from 299 schools) at relatively low cost (7 USD per person mapped) and very quickly (28 working days). All children were analysed by RDTs, but only a sub-sample was also diagnosed by light microscopy. Overall prevalence of schistosomiasis in the surveyed areas was 9.0%, highly associated with poorer access to potable water (OR = 1.5, P<0.001) and defective (OR = 1.2, P<0.001) or absent sanitation infrastructure (OR = 2.0, P<0.001). Overall prevalence of geohelminths, more particularly hookworm infection, was 12.2%, highly associated with presence of faecal occult blood (OR = 1.9, P<0.001). Prevalence maps were produced and hot spots identified to better guide the national programme in drug administration, as well as targeted improvements in water, sanitation and hygiene. The RDTs employed (circulating cathodic antigen and microhaematuria for Schistosoma mansoni and S. haematobium, respectively) performed well, with sensitivities above 80% and specificities above 95%.Conclusion/Significance: This protocol is cost-effective and sensitive to budget limitations and the potential economic and logistical strains placed on the national Ministries of Health. Here we present a high resolution map of disease prevalence levels, and treatment regimens are recommended.Peer reviewedEntomology and Plant Patholog
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