This paper proposes the use of hybrid Hidden Markov Model (HMM)/Artificial Neural Network (ANN) models for recognizing unconstrained offline handwritten texts. The structural part of the optical ...models has been modeled with Markov chains, and a Multilayer Perceptron is used to estimate the emission probabilities. This paper also presents new techniques to remove slope and slant from handwritten text and to normalize the size of text images with supervised learning methods. Slope correction and size normalization are achieved by classifying local extrema of text contours with Multilayer Perceptrons. Slant is also removed in a nonuniform way by using Artificial Neural Networks. Experiments have been conducted on offline handwritten text lines from the IAM database, and the recognition rates achieved, in comparison to the ones reported in the literature, are among the best for the same task.
A large number of porous carbon materials with different properties in terms of porosity, surface chemistry and electrical conductivity, were prepared and systematically studied as electric double ...layer capacitors in aqueous medium with H
2SO
4 as electrolyte. The precursors used are an anthracite, general purpose carbon fibres and high performance carbon fibres, which were activated by KOH, NaOH, CO
2 and steam at different conditions. Among all of them, an activated anthracite with a BET surface area close to 1500
m
2/g, presents the best performance, reaching a value of 320
F/g, using a three-electrode system. The results obtained for all the samples, agree with the well-known relationship between capacitance and porosity, and show that the CO-type oxygen groups have a positive contribution to the capacitance. A very good correlation between the specific capacitance and this type of oxygen groups has been found.
Chemical and electrochemical techniques have been used in order to asses surface functionalities of porous carbon materials. An anthracite has been chemically activated using both KOH and NaOH as ...activating agents. As a result, activated carbons with high micropore volume (higher than 1
cm
3/g) have been obtained. These samples were oxidized with HNO
3 and thermally treated in N
2 flow at different temperatures in order to obtain porous carbon materials with different amounts of surface oxygen complexes. Thermal treatment in H
2 was also carried out. The sample treated with H
2 was subsequently treated in air flow at 450
°C. Thus, materials with very similar porous texture and widely different surface chemistry have been compared. The surface chemistry of the resulting materials was systematically characterized by TPD experiments and XPS measurements. Galvanostatic and voltammetric techniques were used to deepen into the characterization of the surface oxygen complexes. The combination of both, chemical and electrochemical methods provide unique information, regarding the key role of surface chemistry in improving carbon wettability in aqueous solution and the redox processes undergone by the surface oxygen groups. Both contributions are of relevance to understand the use of porous carbons as electrochemical capacitors.
Unconstrained off-line continuous handwritten text recognition is a very challenging task which has been recently addressed by different promising techniques. This work presents our latest ...contribution to this task, integrating neural network language models in the decoding process of three state-of-the-art systems: one based on bidirectional recurrent neural networks, another based on hybrid hidden Markov models and, finally, a combination of both. Experimental results obtained on the IAM off-line database demonstrate that consistent word error rate reductions can be achieved with neural network language models when compared with statistical N-gram language models on the three tested systems. The best word error rate, 16.1%, reported with ROVER combination of systems using neural network language models significantly outperforms current benchmark results for the IAM database.
•We study the use of neural network language models for two state-of-the-art recognizers for unconstrained off-line HTR.•We found consistent improvement when using this language model, combined or not with standard N-grams language models.•The neural network language model scales well with different dictionary sizes for the IAM-DB task.•By combining the two recognition systems, unprecedented accuracy for the IAM database is reported.
Porous carbon materials, with different porosities and surface chemistry have been prepared and characterized to obtain a better understanding of the mechanism of the electrochemical storage of ...hydrogen. The hydrogen storage capacity depends, not only on the porosity of the material, but also on the surface chemistry, which is a critical factor. The results show that the higher the amount of surface oxygen groups, the lower is the hydrogen uptake. Measurement of the number of active carbon sites shows the important role of the unsaturated carbon atoms in the process. In situ Raman spectroscopy has been used in order to further explore the structural changes in the carbon material during the charge–discharge processes. This technique has allowed us to observe the formation of the C(sp
2)
H bonds during the cathodic process and its reversibility during the oxidation step.
The 2006 World Health Organization Air Quality Guidelines recommend using particulate matter having a diameter of under 2.5 micra (PM
2.5) rather than PM
10 as an indicator of air particle ...concentration, a pattern followed by new European directives. Nevertheless, few studies have analysed this new indicator's impact at a European level on daily mortality among a high-risk group, such as persons aged over 75 years.
This study sought to analyse and quantify the effect of PM
2.5 on daily cause-specific mortality among the over-75 age group in the city of Madrid.
Using Poisson regression with Generalized Additive Models (GAM), a longitudinal, ecological time-series study examined the following causes of death: all causes except accidents (International Classification of Diseases-9th revision (ICD 9): 1-799); circulatory causes (ICD 9: 390-459); and respiratory causes (ICD 9: 460-519). These were adjusted for other chemical, biotic and acoustic pollutants. Further control variables considered were: trend; seasonality; influenza epidemics; and autocorrelation between mortality series.
A significant statistical association was detected between daily mean PM
2.5 particle concentrations and all-cause mortality in the city of Madrid. This association was not in evidence for PM
10 concentrations. The Relative Risks found for an increase of 25 µg/m
3 in PM
2.5 concentrations were as follows: all-cause mortality, 1.057 (1.025–1.088); circulatory-cause mortality, 1.088 (1.041–1.135); and respiratory-cause mortality, 1.122 (1.056–1.189). The Attributable Risks were 5.41%, 8.12% and 10.90% respectively. This effect was observed in the short term (lags 1–2).
Our results indicate a strong impact of PM
2.5 concentrations on daily mortality among the over-75 age group in Madrid, and underscore the need for measures aimed at lowering the concentration levels of this primary air pollutant in large cities, particularly by reducing motor vehicle traffic, the main source of such pollutant emission in urban atmospheres.
Several strands of evidence question the dogma that human mitochondrial DNA (mtDNA) is inherited exclusively down the maternal line, most recently in three families where several individuals harbored ...a 'heteroplasmic haplotype' consistent with biparental transmission. Here we report a similar genetic signature in 7 of 11,035 trios, with allelic fractions of 5-25%, implying biparental inheritance of mtDNA in 0.06% of offspring. However, analysing the nuclear whole genome sequence, we observe likely large rare or unique nuclear-mitochondrial DNA segments (mega-NUMTs) transmitted from the father in all 7 families. Independently detecting mega-NUMTs in 0.13% of fathers, we see autosomal transmission of the haplotype. Finally, we show the haplotype allele fraction can be explained by complex concatenated mtDNA-derived sequences rearranged within the nuclear genome. We conclude that rare cryptic mega-NUMTs can resemble paternally mtDNA heteroplasmy, but find no evidence of paternal transmission of mtDNA in humans.
The cycle efficiency and capacitance of two KOH-activated carbons have been tested in 0.5M tetraethylammonium tetrafluoroborate in propylene carbonate (TEABF4/PC) under different conditions of ...temperature (room temperature and 70°C) and voltage (0–3V). The materials tested include a KOH-activated carbon before and after treatment with different acids and hydrogen at high temperature to remove most of the oxygen groups and inorganic impurities. Porous texture and surface chemistry characterization have been carried out before and after cycling to understand the changes in the properties of activated carbons during the cycles. It has been observed that the treatment with different acids and hydrogen at high temperature produces materials with higher cycling stability. The results point out that the observed electrode degradation is mainly due to some pore blockage caused by reaction of the solvent with the functional groups on the carbon. The blockage of porosity is higher for the sample with higher oxygen content, indicating that the treatment carried out to remove the oxygen groups has an important positive effect, giving electrodes with a much lower degradation under very aggressive conditions in a TEABF4/PC medium.
Bronchiectasis can result from infectious, genetic, immunological and allergic causes. 60-80% of cases are idiopathic, but a well-recognised genetic cause is the motile ciliopathy, primary ciliary ...dyskinesia (PCD). Diagnosis of PCD has management implications including addressing comorbidities, implementing genetic and fertility counselling and future access to PCD-specific treatments. Diagnostic testing can be complex; however, PCD genetic testing is moving rapidly from research into clinical diagnostics and would confirm the cause of bronchiectasis.
This observational study used genetic data from severe bronchiectasis patients recruited to the UK 100,000 Genomes Project and patients referred for gene panel testing within a tertiary respiratory hospital. Patients referred for genetic testing due to clinical suspicion of PCD were excluded from both analyses. Data were accessed from the British Thoracic Society audit, to investigate whether motile ciliopathies are underdiagnosed in people with bronchiectasis in the UK.
Pathogenic or likely pathogenic variants were identified in motile ciliopathy genes in 17 (12%) out of 142 individuals by whole-genome sequencing. Similarly, in a single centre with access to pathological diagnostic facilities, 5-10% of patients received a PCD diagnosis by gene panel, often linked to normal/inconclusive nasal nitric oxide and cilia functional test results. In 4898 audited patients with bronchiectasis, <2% were tested for PCD and <1% received genetic testing.
PCD is underdiagnosed as a cause of bronchiectasis. Increased uptake of genetic testing may help to identify bronchiectasis due to motile ciliopathies and ensure appropriate management.
Whole-genome sequencing (WGS) permits comprehensive cancer genome analyses, revealing mutational signatures, imprints of DNA damage and repair processes that have arisen in each patient's cancer. We ...performed mutational signature analyses on 12,222 WGS tumor-normal matched pairs, from patients recruited via the UK National Health Service. We contrasted our results to two independent cancer WGS datasets, the International Cancer Genome Consortium (ICGC) and Hartwig Foundation, involving 18,640 WGS cancers in total. Our analyses add 40 single and 18 double substitution signatures to the current mutational signature tally. Critically, we show for each organ, that cancers have a limited number of 'common' signatures and a long tail of 'rare' signatures. We provide a practical solution for utilizing this concept of common versus rare signatures in future analyses.
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