On the explanatory power of principal components

We show that if we have an orthogonal base ($u_1,\ldots,u_p$) in a $p$-dimensional vector space, and select $p+1$ vectors $v_1,\ldots, v_p$ and $w$ such that the vectors traverse the origin, then the probability of $w$ being to closer to all the vectors in the base than to $v_1,\ldots, v_p$ is at least 1/2 and converges as $p$ increases to infinity to a normal distribution on the interval [-1,1]; i.e., $\Phi(1)-\Phi(-1)\approx0.6826$. This result has relevant consequences for Principal Components Analysis in the context of regression and other learning settings, if we take the orthogonal base as the direction of the principal components.Comment: 10 pages, 3 figure

Robotic navigation algorithm with machine vision

In the field of robotics, it is essential to know the work area in which the agent is going to develop, for that reason, different methods of mapping and spatial location have been developed for different applications. In this article, a machine vision algorithm is proposed, which is responsible for identifying objects of interest within a work area and determining the polar coordinates to which they are related to the observer, applicable either with a fixed camera or in a mobile agent such as the one presented in this document. The developed algorithm was evaluated in two situations, determining the position of six objects in total around the mobile agent. These results were compared with the real position of each of the objects, reaching a high level of accuracy with an average error of 1.3271% in the distance and 2.8998% in the angle

Predicting Atrial Fibrillation Recurrence After Catheter Ablation Through Time Variability of P-wave Features

[EN] Nowadays, the first-line therapy for paroxysmal atrial fibrillation (PAF) is pulmonary vein isolation through catheter ablation. However, the success rate of this procedure is still not as high as desirable. Thus, preoperative prediction of early AF recurrence after ablation is a challenge to select optimal candidates for the intervention. To this end, some promising predictors based on the P-wave in short ECG signals have been proposed in the last years. However, evolution of the P-wave along the time has still not been analyzed. Hence, the present work studies how time variability of two features of the P-wave predicts midterm cryoablation failure. For 45 PAF patients, a standard 12-lead ECG signal was obtained for 5 minutes before ablation. An automatic algorithm was then used to delineate all P-waves in lead II, and duration and amplitude were computed. The resulting time series were characterized by their mean, standard deviation and coefficient of variation (CV). Correlating these measures with ablation outcome, the CV for both parameters obtained the best discrimination between patients. In fact, compared with the mean value, the CV for both features obtained accuracies 10% greater, thus achieving values of 70%. These outcomes entail that time variability of the P-wave can reveal new information about the proarrhythmic condition of the patients, thus improving predictions of ablation failure.Ruiz, A.; Arias, MA.; Puchol, A.; Pachon, MI.; Rieta, JJ.; Alcaraz, R. (2020). Predicting Atrial Fibrillation Recurrence After Catheter Ablation Through Time Variability of P-wave Features. IEEE. 1-4. https://doi.org/10.22489/CinC.2020.366S1

Comparative Study of Convolutional Neural Networks for ECG Quality Assessment

[EN] In the last years, convolutional neural networks (CNNs) have become popular in ECG analysis, since they do not require pre-processing stages, nor specific pre-training. However, their ability for ECG quality assessment has still not been thoroughly assessed. Hence, this work introduces a comparison about the ability of several CNN algorithms to classify between high and low-quality ECGs. Taking advantage of the concept of transfer learning, five common pre-trained CNNs were analyzed, such as AlexNet, GoogLeNet, VGG16, ResNet18 and InceptionV3. They were fed with 2-D images obtained by turning 5 second-length ECG segments into scalograms through a continuous Wavelet transform. To train and validate the algorithms, 1,168 noisy ECG intervals, along with other 1,200 ECG excerpts with sufficient quality for their further interpretation, were extracted from a public database. The obtained results showed that all CNNs provided mean values of accuracy between 89 and 91%, but notable difference in terms of computational load were noticed. Thus, AlexNet was the fastest algorithm, requiring notably less CPU usage and memory than the remaining methods. Consequently, this CNN exhibited the best trade-off between high-quality ECG identification accuracy and computational load, and it could be considered as the most convenient algorithm for ECG quality assessment.This research has been supported by the grants DPI2017-83952-C3 from MINECO/AEI/FEDER EU, SBPLY/17/180501/000411 from Junta de Comunidades de Castilla-La Mancha and AICO/2019/036 from Generalitat Valenciana.Huerta, A.; Martinez-Rodrigo, A.; Puchol, A.; Pachon, MI.; Rieta, JJ.; Alcaraz, R. (2020). Comparative Study of Convolutional Neural Networks for ECG Quality Assessment. IEEE. 1-4. https://doi.org/10.22489/CinC.2020.370S1

The Bose–Hubbard model with squeezed dissipation

The stationary properties of the Bose–Hubbard model under squeezed dissipation are investigated. The dissipative model does not possess aU (1) symmetry but conserves parity. We find that 〈a j 〉 = 0 always holds, so no symmetry breaking occurs. Without the onsite repulsion, the linear case is known to be critical. At the critical point the system freezes to an EPR state with infinite two mode entanglement. We show here that the correlations are rapidly destroyed whenever the repulsion is switched on. As we increase the latter, the system approaches a thermal state with an effective temperature defined in terms of the squeezing parameter in the dissipators. We characterize this transition by means of a Gutzwiller ansatz and the Gaussian Hartree–Fock–Bogoliubov approximation

GabiPD: the GABI primary database—a plant integrative ‘omics’ database

The GABI Primary Database, GabiPD (http://www.gabipd.org/), was established in the frame of the German initiative for Genome Analysis of the Plant Biological System (GABI). The goal of GabiPD is to collect, integrate, analyze and visualize primary information from GABI projects. GabiPD constitutes a repository and analysis platform for a wide array of heterogeneous data from high-throughput experiments in several plant species. Data from different ‘omics’ fronts are incorporated (i.e. genomics, transcriptomics, proteomics and metabolomics), originating from 14 different model or crop species. We have developed the concept of GreenCards for text-based retrieval of all data types in GabiPD (e.g. clones, genes, mutant lines). All data types point to a central Gene GreenCard, where gene information is integrated from genome projects or NCBI UniGene sets. The centralized Gene GreenCard allows visualizing ESTs aligned to annotated transcripts as well as displaying identified protein domains and gene structure. Moreover, GabiPD makes available interactive genetic maps from potato and barley, and protein 2DE gels from Arabidopsis thaliana and Brassica napus. Gene expression and metabolic-profiling data can be visualized through MapManWeb. By the integration of complex data in a framework of existing knowledge, GabiPD provides new insights and allows for new interpretations of the data

Efeito do Esteroíde nos Limiares Agudos de um Eletrodo Atrial e Ventricular de Fixaçao Ativa

Objetivo: Comparar a performace de um eletrodo bipolar permanente com fixaçao ativa e colar de esteróide, com outro eletrodo semelhante, mas sem o colar de esteróide. Material e Método: Este estudo foi realizado em 2 fases em 3 centros no Brasil: na fase atrial eletrodos Sweet Tip Rx e Sweet Tip foram implantados em 16 e 8 pacientes, respectivamente. Em todos os pacientes os limiares de voltagem (largura de pulso = 0,5 ms) e a largura de pulso (amplitude = 1,5V ) foram medidos por ocasiao da alta hospitalar, 2 semanas e 3 ou 4 meses após o implante. Resultados: Na avaliaçao de 2 semanas a média dos limiares de voltagem foi de 0,57± 0,04 V para o Sweet Tip Rx e 1,0 ± 0,19V para o Sweet Tip (p0,49) e, para os eletrodos ventriculares, 0,14 ± 0,02ms para o Sweet Tip Rx e 0,31 ± 0,05ms para o Sweet Tip (pConclusao: Os eletrodos envolvidos com esteróide tiveram um limiar significativamente menor após o implante

PlantTFDB: a comprehensive plant transcription factor database

Transcription factors (TFs) play key roles in controlling gene expression. Systematic identification and annotation of TFs, followed by construction of TF databases may serve as useful resources for studying the function and evolution of transcription factors. We developed a comprehensive plant transcription factor database PlantTFDB (http://planttfdb.cbi.pku.edu.cn), which contains 26 402 TFs predicted from 22 species, including five model organisms with available whole genome sequence and 17 plants with available EST sequences. To provide comprehensive information for those putative TFs, we made extensive annotation at both family and gene levels. A brief introduction and key references were presented for each family. Functional domain information and cross-references to various well-known public databases were available for each identified TF. In addition, we predicted putative orthologs of those TFs among the 22 species. PlantTFDB has a simple interface to allow users to search the database by IDs or free texts, to make sequence similarity search against TFs of all or individual species, and to download TF sequences for local analysis

Efeito do Esteroíde nos Limiares Agudos de um Eletrodo Atrial e Ventricular de Fixaçao Ativa

Objetivo: Comparar a performace de um eletrodo bipolar permanente com fixaçao ativa e colar de esteróide, com outro eletrodo semelhante, mas sem o colar de esteróide. Material e Método: Este estudo foi realizado em 2 fases em 3 centros no Brasil: na fase atrial eletrodos Sweet Tip Rx e Sweet Tip foram implantados em 16 e 8 pacientes, respectivamente. Em todos os pacientes os limiares de voltagem (largura de pulso = 0,5 ms) e a largura de pulso (amplitude = 1,5V ) foram medidos por ocasiao da alta hospitalar, 2 semanas e 3 ou 4 meses após o implante. Resultados: Na avaliaçao de 2 semanas a média dos limiares de voltagem foi de 0,57± 0,04 V para o Sweet Tip Rx e 1,0 ± 0,19V para o Sweet Tip (p0,49) e, para os eletrodos ventriculares, 0,14 ± 0,02ms para o Sweet Tip Rx e 0,31 ± 0,05ms para o Sweet Tip (pConclusao: Os eletrodos envolvidos com esteróide tiveram um limiar significativamente menor após o implante

Health Services Utilization, Work Absenteeism and Costs of Pandemic Influenza A (H1N1) 2009 in Spain: A Multicenter-Longitudinal Study

Background: The aim of this study was to estimate healthcare resource utilization, work absenteeism and cost per patient with pandemic influenza (H1N1)2009, from its beginning to March 2010, in Spain. We also estimated the economic impact on healthcare services. Methods and Findings: Longitudinal, descriptive,multicenter study of in- and outpatients with confirmed diagnosis of influenza A (H1N1) in Spain. Temporal distribution of cases was comparable to that in Spain. Information of healthcare and social resources used from one week before admission (inpatient) or index-medical visit (outpatient) until recovery was gathered. Unit cost was imputed to utilization frequency for the monetary valuation of use. Mean cost per patient was calculated. A sensitivity analysis was conducted, and variables correlated with cost per patient were identified. Economic impact on the healthcare system was estimated using healthcare costs per patient and both, the reported number of confirmed and clinical cases in Spain. 172 inpatients and 224 outpatients were included. Less than 10% were over 65 years old and more than 50% had previous comorbidities. 12.8% of inpatients were admitted to the Intensive Care Unit. Mean length of hospital stay of patients not requiring critical care was 5 days (SD =4.4). All working-inpatients and 91.7% working-outpatients went on sick leave. On average, work absenteeism was 30.5 days (SD=20.7) for the first ones and 9 days (SD= 6.3) for the latest. Caregivers of 21.7% of inpatients and 8.5% of outpatients also had work absenteeism during 10.7 and 4.1 days on average respectively. Mean cost was J6,236/inpatient (CI95%=1,384-14,623) and J940/outpatient (CI95% =66-3,064). The healthcare economic burden of patients with confirmed influenza was J144,773,577 (IC95% 13,753,043-383,467,535). More than 86% of expenditures were a result of outpatients" utilization. Conclusion: Cost per H1N1-patient did not defer much from seasonal influenza estimates. Hospitalizations and work absenteeism represented the highest cost per patient