A deep reinforcement learning approach for active SLAM

In this paper, we formulate the active SLAM paradigm in terms of model-free Deep Reinforcement Learning, embedding the traditional utility functions based on the Theory of Optimal Experimental Design in rewards, and therefore relaxing the intensive computations of classical approaches. We validate such formulation in a complex simulation environment, using a state-of-the-art deep Q-learning architecture with laser measurements as network inputs. Trained agents become capable not only to learn a policy to navigate and explore in the absence of an environment model but also to transfer their knowledge to previously unseen maps, which is a key requirement in robotic exploration

Influence of delay time on regularity estimation for voice pathology detection

The employment of nonlinear analysis techniques for automatic voice pathology detection systems has gained popularity due to the ability of such techniques for dealing with the underlying nonlinear phenomena. On this respect, characterization using nonlinear analysis typically employs the classical Correlation Dimension and the largest Lyapunov Exponent, as well as some regularity quantifiers computing the system predictability. Mostly, regularity features highly depend on a correct choosing of some parameters. One of those, the delay time �, is usually fixed to be 1. Nonetheless, it has been stated that a unity � can not avoid linear correlation of the time series and hence, may not correctly capture system nonlinearities. Therefore, present work studies the influence of the � parameter on the estimation of regularity features. Three � estimations are considered: the baseline value 1; a � based on the Average Automutual Information criterion; and � chosen from the embedding window. Testing results obtained for pathological voice suggest that an improved accuracy might be obtained by using a � value different from 1, as it accounts for the underlying nonlinearities of the voice signal

Detección de anticuerpos contra el virus de inmunodeficiencia humana (VIH), en estudiantes universitarios de egreso que asisten a examen a la unidad de salud de la Universidad de San Carlos de Guatemala

Se determinó la prevalencia de anticuerpos contra el Virus de Inmunodeficiencia Humana en 500 estudiantes universitarios de egreso provenientes de diferentes facultades de la Universidad de San Carlos, que asistieron a efectuarse el examen de salud en el periodo de octubre a noviembre de 1993 y de enero a marzo de 1994.   Las muestras fueron obtenidas en forma voluntaria y confidencial, incluyéndose estudiantes de ambos sexos comprendidos entre las edades de 20 a 40 años. Se excluyó del estudio únicamente a los estudiantes que no aceptaron realizarse la prueba

Feature-Based Multi-Hypothesis Localization and Tracking for Mobile Robots Using Geometric Constraints

In this paper we present a new probabilistic feature-based approach to multi-hypothesis global localization and pose tracking. Hypotheses are generated using a constraintbased search in the interpretation tree of possible localto-global pairings. This results in a set of robot location hypotheses of unbounded accuracy. For tracking, the same constraint-based technique is used. It performs track splitting as soon as location ambiguities arise from uncertainties and sensing. This yields a very robust localization technique which can deal with significant errors from odometry, collisions and kidnapping. Simulation experiments and first tests with a real robot demonstrate these properties at very low computational cost. The presented approach is theoretically sound which makes that the only parameter is the significance level on which all statistical decisions are taken

Identification of Mexican Maize Races (Zea mays L.) with Drought Tolerance using Osmotic Potential Experiments for Genetic Breeding

Received: July 13th, 2023 ; Accepted: September 23rd, 2023 ; Published: October 23rd, 2023 ; Correspondence: [email protected] (Zea mays L.) is the third most important cereal crop worldwide after wheat and rice per cultivated area with 249,225,876 hectares and the most important crop for number of harvested grain tons with 1,482,997,259 in 2021. Some native Mexican maize races could be a source for drought tolerance to improve commercial cultivars and hybrids. The experiments were conducted using various osmotic pressures (OP) induced by polyethylene glycol (PEG-6000) (0, -0.05, -0.15, -0.30 and -0.49 MPa) simulating an increase of drought stress in ten maize genotypes. The main objectives of this study were the evaluation of germination and seedling growth components in response to drought stress and the identification of sources of drought tolerance in Mexican maize races. Apachito-r showed an increased germination in 110.4%, Cristalino-079 had a decreased germination in 98.7% and Cristalino-279 reduced its germination in a 91.1% compared to the control. Apachito-r outstands in root length at -0.05 OP increasing 200.1% and at -0.49 increasing 129.8%. The values for stem length were decreasing as the OP was increasing and only Apachito-r showed a significant difference at -0.30 MPa decreasing 39.8% respect to its control. Cristalino-279 showed significant difference in the variable root fresh weight and its value outstand at -0.15 increasing 267.2%, at -0.30 increasing 281.6% and at -0.49 MPa increasing 189.3% compared to the control in water. The variable root dry weight had the highest value for Apachito-r at -0.05 MPa increasing in a 189.4%, decreasing at -0.15 in 72% and at -0.30 MPa in a 79.8% and increasing at -0.49 MPa in 112.3%. Also noteworthy are E-zapata-r increasing 190.5% and Cristalino-061 increasing 142.9% at -0.30. E-zapata-r at -0.49 increased 115.1%. Cristalino-279 showed significant difference in the variable stem fresh weight and its value outstand at -0.05, -0.15 and -0.30 MPa increasing 146.7%, 103.7% and 60.2% respectively. Finally, in stem dry weight the tendency was to decrease as OP was increasing, however Cristalino-279 showed differences at -0.30 decreasing in 89.5% and at -0.49 MPa increasing in a 143.5% respect to the control. The most drought tolerant genotypes were Cristalino-279, Apachito-r, Azul and 8-carreras-PP. The most tolerant genotypes showed greater root length, greater root fresh and dry weight, better germination and greater stem length. Resistant and susceptible genotypes are ideal material to understand the physical and chemical mechanisms related to drought tolerance. Cristalino-279 shows the best level of drought tolerance at all levels of osmotic pressure, this genotype can be used as a source of drought tolerance for the improvement of commercial maize

A New and Efficient Enrichment Method for Metagenomic Sequencing of Monkeypox Virus

[Abstract] Background The methodology described in previous literature for Monkeypox virus (MPXV) sequencing shows low efficiency when using metagenomic approaches. The aim of the present study was to evaluate a new fine-tuned method for extraction and enrichment of genomic MPXV DNA using clinical samples and to compare it to a non-enrichment metagenomic approach. Results A new procedure that allows sample enrichment in MPXV DNA, avoiding wasting the sequencing capacity in human DNA, was designed. This procedure consisted of host DNA depletion using a saponin/NaCl combination treatment and DNase, together with high g-force centrifugations. After typical quality control, samples using the enrichment method contained around 96% of reads not classified as human DNA, while the non-enrichment protocol showed around 5-10%. When reads not belonging to Orthopoxvirus were removed, enriched samples kept about 50% of the original read counts, while non-enriched ones kept only 2-7%. Conclusions Results showed a very significant improvement in sequencing efficiency, increasing the number of reads belonging to MPXV, the depth of coverage and the trustworthiness of the consensus sequences. This, in turn, allows for more samples to be included in a single cartridge, reducing costs and time to diagnosis, which can be very important factors when dealing with a contagious disease.This work was supported by a grant from the SERGAS-Galician Healthcare Service (Program “Innova Saúde”) to GB, by CIBERINFEC and also by Instituto de Salud Carlos III (ISCIII) through the projects PI20/00413 to MP and PI21/00704 to G

GMM-based classifiers for the automatic detection of obstructive sleep apnea

The aim of automatic pathological voice detection systems is to serve as tools, to medical specialists, for a more objective, less invasive and improved diagnosis of diseases. In this respect, the gold standard for those system include the usage of a optimized representation of the spectral envelope, either based on cepstral coefficients from the mel-scaled Fourier spectral envelope (Mel-Frequency Cepstral Coefficients) or from an all-pole estimation (Linear Prediction Coding Cepstral Coefficients) forcharacterization, and Gaussian Mixture Models for posterior classification. However, the study of recently proposed GMM-based classifiers as well as Nuisance mitigation techniques, such as those employed in speaker recognition, has not been widely considered inpathology detection labours. The present work aims at testing whether or not the employment of such speaker recognition tools might contribute to improve system performance in pathology detection systems, specifically in the automatic detection of Obstructive Sleep Apnea. The testing procedure employs an Obstructive Sleep Apnea database, in conjunction with GMM-based classifiers looking for a better performance. The results show that an improved performance might be obtained by using such approach

P28 85. Análisis de la supervivencia a corto y medio plazo de la cirugía de aorta ascendente

ObjetivosEvaluar la mortalidad hospitalaria y la supervivencia a medio plazo de los pacientes sometidos a una cirugía de aorta ascendente y determinar cuáles son sus factores de riesgo.Material y métodosSe analizó de forma retrospectiva toda la población de pacientes sometidos a un procedimiento quirúrgico de aorta ascendente (sustitución con o sin cirugía valvular o de raíz asociada) entre enero de 2003 y diciembre de 2008. Se evaluó la mortalidad hospitalaria y la supervivencia absoluta en el seguimiento, y mediante análisis uni y multivariante se determinaron las correspondientes variables predictoras.ResultadosTrescientos sesenta y cinco pacientes fueron sometidos de forma consecutiva a algún procedimiento quirúrgico de la aorta ascendente. Edad media: 63,1 años (desviación estándar [DE] 13); n = 99 (27,1%) fueron mujeres; n = 58 (15,9%) habían sido sometidos a una cirugía previa. En 32 pacientes se sustituyó total o parcialmente el arco aórtico. EuroSCORE mediano de 11,72% (interquartile range [IQR]: 6,78-20,43). La mortalidad hospitalaria fue 7,7% (n = 28). Los predictores de mortalidad en análisis multivariante fueron: cirugía cardíaca previa (odds ratio [OR]: 3,18; p = 0,045), tabaquismo activo (OR: 5,7; p = 0,021), insuficiencia renal (OR: 3,03; p = 0,043), estado crítico preoperatorio (OR: 5,63; p = 0,005), edad (OR: 1,06; p = 0,018) y cirugía coronaria asociada (OR: 3,17; p = 0,35). La supervivencia a 1, 3 y 5 años fue 96, 94 y 92%. Sólo edad (hazard ratio [HR]: 1,08; p = 0,022) e hipertensión pulmonar grave (HR: 3,5; p = 0,026) fueron predictores independientes de mortalidad en el seguimiento.ConclusionesEn nuestra experiencia, la sustitución de la aorta ascendente demuestra una baja mortalidad hospitalaria y una adecuada supervivencia a medio plazo

Band structure and reflectance for a nonlinear one-dimensional photonic crystal

We consider a model for a one-dimensional photonic crystal formed by a succession of Kerr-type equidistant spaceless interfaces immersed in a linear medium. We calculate the band structure and reflectance of this structure as a function of the incident wave intensity, and find two main behaviors: the appearance of prohibited bands, and the separation and narrowing of these bands. A system with these features is obtained by alternating very thin slabs of a soft matter material with thicker solid films, which can be used to design a device to control light propagation for specific wavelength intervals and light intensities.Comment: 6 pages, 6 figure