PRM-RL: Long-range Robotic Navigation Tasks by Combining Reinforcement Learning and Sampling-based Planning

We present PRM-RL, a hierarchical method for long-range navigation task completion that combines sampling based path planning with reinforcement learning (RL). The RL agents learn short-range, point-to-point navigation policies that capture robot dynamics and task constraints without knowledge of the large-scale topology. Next, the sampling-based planners provide roadmaps which connect robot configurations that can be successfully navigated by the RL agent. The same RL agents are used to control the robot under the direction of the planning, enabling long-range navigation. We use the Probabilistic Roadmaps (PRMs) for the sampling-based planner. The RL agents are constructed using feature-based and deep neural net policies in continuous state and action spaces. We evaluate PRM-RL, both in simulation and on-robot, on two navigation tasks with non-trivial robot dynamics: end-to-end differential drive indoor navigation in office environments, and aerial cargo delivery in urban environments with load displacement constraints. Our results show improvement in task completion over both RL agents on their own and traditional sampling-based planners. In the indoor navigation task, PRM-RL successfully completes up to 215 m long trajectories under noisy sensor conditions, and the aerial cargo delivery completes flights over 1000 m without violating the task constraints in an environment 63 million times larger than used in training.Comment: 9 pages, 7 figure

An assessment of chemical contaminants in the marine sediments of southwest Puerto Rico

This report summarizes the results of a characterization of chemical contaminants in the sediments in southwest Puerto Rico. The report is part of a project to integrate various analytical specialties to assess linkages between chemical contaminants and the condition of coral reefs. In this phase of the project, over 120 chemical contaminants were analyzed in sediments collected, including a number of organic (e.g., hydrocarbons), inorganic (e.g., metals), and biological (bacterial) compounds/analytes. The report also provides a preliminary analysis of the association between sediment contaminants and coral species richness. Overall, the levels of chemical contaminants in the study area between Guanica Bay and the town of La Parguera were fairly low. At most of the sites sampled, particularly adjacent to the town of La Parguera, concentrations of organic and inorganic contaminants were below the median values from NOAA’s National Status and Trends Program, which monitors the Nation’s coastal and estuarine waters for chemical contaminants. Elevated levels of a number of contaminant classes were seen at the two sites sampled within Guanica Bay. An initial analysis of modeled PAH (hydrocarbon) data and coral species richness (reef building species) indicated a strong negative correlation between the presence of PAHs in the sediments and coral species richness. Additional work is needed to assess possible reasons for this observed pattern. (PDF contains 126 pages)

Micro-Raman Study of the Fatigue and Fracture Behaviour of single PA66 Fibres. Comparison with single PET and PP Fibres

International audienceThe micro/nano structural evolution of PA66, PP, PBO and PET (both drawn and precursor) fibres, before and after tensile loading, fatigue and ultimately, failure has been studied by Raman microspectroscopy using two probes. The Raman analysis has used low wavenumber collective modes at <150 cm-1 as representative of the crystalline and amorphous chains and stretching and bending modes, as representative of the C-C bond local behaviour. Wavenumber and bandwith distribution across fibre/precursors diameters revealed different types of skin/core heterogeneities. The in situ analysis at different strain levels showed that amorphous zones in the fibres accommodate the stress differently. Slight tensile straining is observed for crystalline PA 66 chains, and compression for PP and PET chains. Post mortem analysis of a series of fibres failed in fatigue showed that the amorphous domains were highly stressed during failure and a resulting residual stress could be measured

Human Pleural Fluid Elicits Pyruvate and Phenylalanine Metabolism in Acinetobacter baumannii to Enhance Cytotoxicity and Immune Evasion

The CCAAT box-harboring proteins represent a family of heterotrimeric transcription factors which is highly conserved in eukaryotes. In fungi, one of the particularly important homologs of this family is the Hap complex that separates the DNA-binding domain from the activation domain and imposes essential impacts on regulation of a wide range of cellular functions. So far, a comprehensive summary of this complex has been described in filamentous fungi but not in the yeast. In this review, we summarize a number of studies related to the structure and assembly mode of the Hap complex in a list of representative yeasts. Furthermore, we emphasize recent advances in understanding the regulatory functions of this complex, with a special focus on its role in regulating respiration, production of reactive oxygen species (ROS) and iron homeostasis.Fil: Nyah, Rodman. California State University; Estados UnidosFil: Martinez, Jasmine. California State University; Estados UnidosFil: Fung, Sammie. California State University; Estados UnidosFil: Nakanouchi, Jun. California State University; Estados UnidosFil: Myers, Amber L.. California State University; Estados UnidosFil: Harris, Caitlin M.. California State University; Estados UnidosFil: Dang, Emily. California State University; Estados UnidosFil: Fernandez, Jennifer. California State University; Estados UnidosFil: Liu, Christine. California State University; Estados UnidosFil: Mendoza, Anthony M.. California State University; Estados UnidosFil: Jimenez, Verónica. California State University; Estados UnidosFil: Nikolaidis, Nikolas. California State University; Estados UnidosFil: Brennan, Catherine A.. California State University; Estados UnidosFil: Bonomo, Robert A.. Louis Stokes Cleveland Department of Veterans Affairs Medical Cente; Estados Unidos. Center for Antimicrobial Resistance and Epidemiology; Estados Unidos. Case Western Reserve University School of Medicine; Estados UnidosFil: Sieira, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Ramirez, Maria Soledad. California State University; Estados Unido

Uso de Google Classroom como repositorio de robótica práctica: PieroAcademy

En el desarrollo de practicas de laboratorio en algunas asignaturas del área de ingeniería de sistemas y automática, los alumnos recaban información relativa a equipos y componentes de diversas fuentes externas. Los resultados de su trabajo, que en muchos casos son de gran calidad, pasan al olvido una vez evaluados. Con el objetivo de poner en valor y mejorar el aprovechamiento de dichos trabajos, se propone la creaci´on de un repositorio controlado de informaci´on, donde los estudiantes puedan recopilar parte del material necesario para la realizaci´on de sus trabajos, ejemplos de ayuda, y tutoriales realizados por otros estudiantes; pero ademas contribuir a ampliar la información mediante sus propias experiencias. En la implementación del repositorio, se hace uso de las herramientas proporcionadas por la G Suite for Education (GSFE), siendo el núcleo, la herramienta denominada Google Classroom. En este trabajo se describe la implantación y experiencia con este sistema como medio para gestionar un repositorio organizado donde sus denominadas"clases", toman contenido de unidades temáticas; con la versatilidad de su acceso desde dispositivos móviles y la capacidad de reutilización en asignaturas reales.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Proyecto de Innovación educativa de la Universidad de Málaga PIE 17-118

A Neutron Star Binary Merger Model for GW170817/GRB170817a/SSS17a

The merging neutron star gravitational wave event GW170817 has been observed throughout the entire electromagnetic spectrum from radio waves to $\gamma$-rays. The resulting energetics, variability, and light curves are shown to be consistent with GW170817 originating from the merger of two neutron stars, in all likelihood followed by the prompt gravitational collapse of the massive remnant. The available $\gamma$-ray, X-ray and radio data provide a clear probe for the nature of the relativistic ejecta and the non-thermal processes occurring within, while the ultraviolet, optical and infrared emission are shown to probe material torn during the merger and subsequently heated by the decay of freshly synthesized $r$-process material. The simplest hypothesis that the non-thermal emission is due to a low-luminosity short $\gamma$-ray burst (sGRB) seems to agree with the present data. While low luminosity sGRBs might be common, we show here that the collective prompt and multi-wavelength observations are also consistent with a typical, powerful sGRB seen off-axis. Detailed follow-up observations are thus essential before we can place stringent constraints on the nature of the relativistic ejecta in GW170817.Comment: 9 pages, 5 figures, accepted to ApJ Letter

Control a Baja Velocidad de una Rueda con Motor de Accionamiento Directo mediante Ingeniería Basada en Modelos

Los motores de corriente continua sin escobillas (BLDC) con accionamiento directo suponen una solución compacta para la tracción en vehículos eléctricos, si bien requieren detectar la posición del rotor, habitualmente mediante un codificador angular de efecto Hall dentro del mismo motor. No obstante, la ausencia de reductora y a la dificultad de añadir un codificador angular de precisión suponen un reto para lograr un control preciso a baja velocidad, especialmente si se hace uso de controladoras industriales donde las posibilidades de programación son limitadas. Este trabajo propone aplicar una estrategia de ingeniería basada en modelos (MDE) para el control a baja velocidad de una rueda con motor BLDC de accionamiento directo. En particular, se presenta la solución para un caso de estudio basado en hardware de bajo coste que incluye una tarjeta Arduino Due, una controladora Roboteq HBL2360 y un interfaz de comunicación de bus CAN. La solución MDE basada en Simulink ofrece simplicidad conceptual, capacidad de adaptación a nuevas especificaciones de diseño usando herramientas de diseño avanzadas y generación de código automática. El artículo ofrece resultados experimentales obtenidos sobre el sistema real.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech, CICYT DPI2015-65186-R y el proyecto de Innovación educativa de la Universidad de Málaga PIE 15-18

Comparative effectiveness of levetiracetam, valproate and carbamazepine among elderly patients with newly diagnosed epilepsy: subgroup analysis of the randomized, unblinded KOMET study

BACKGROUND: Few clinical trials have evaluated the efficacy and tolerability of antiepileptic drugs (AEDs) as initial monotherapy for elderly patients. METHODS: This post-hoc subgroup analysis of data from an unblinded, randomized, 52-week superiority study (KOMET) compared the effectiveness of levetiracetam (LEV) with extended-release sodium valproate (VPA-ER) and controlled-release carbamazepine (CBZ-CR) as monotherapy in patients aged 60 years with newly diagnosed epilepsy. The physician chose VPA or CBZ as preferred standard treatment; patients were randomized to standard AEDs or LEV. The primary endpoint was time to treatment withdrawal. Results are exploratory, since KOMET was not powered for a subgroup analysis by age. RESULTS: Patients (n = 308) were randomized to LEV (n = 48) or VPA-ER (n = 53) in the VPE-ER stratum or to LEV (n = 104) or CBZ-CR (n = 103) in the CBZ-CR stratum. Mean age was 69.6 years, range 60.2-89.9 years (intention-to-treat population n = 307). Time to treatment withdrawal hazard ratio [HR] (95 % confidence interval [CI]) for LEV vs. standard AEDs was 0.44 (0.28-0.67); LEV vs. VPA-ER: 0.46 (0.16-1.33); LEV vs. CBZ-CR: 0.45 (0.28-0.72). Twelve-month withdrawal rates were: LEV vs. standard AEDs, 20.4 vs. 38.7 %; LEV vs. VPA-ER, 10.4 vs. 23.1 %; LEV vs. CBZ-CR, 25.0 vs. 46.6 %. Time to first seizure was similar between LEV and standard AEDs (HR: 0.92, 95 % CI: 0.63-1.35), LEV and VPA-ER (0.77, 0.38-1.56), and LEV and CBZ-CR (1.02, 0.64-1.63). Adverse events were reported by 76.2, 67.3, and 82.5 % of patients for LEV, VPA-ER, and CBZ-CR, respectively. Discontinuation rates due to AEs were 11.3, 10.2, and 35.0 % for LEV, VPA-ER, and CBZ-CR, respectively.CONCLUSIONS: Time to treatment withdrawal was longer with LEV compared with standard AEDs. This finding was driven primarly by the result in the CBZ-CR stratum, which in turn was likely due to the more favorable tolerability profile of LEV. Results of this post-hoc analysis suggest that LEV(VLID)195291

La Frontera de COVID-19

Journal #15 from Media Rise's Quarantined Across Borders Collection by Anthony Ramirez. From United States. Quarantined in United States.In this essay, I discuss the various fronteras (borders) caused by the COVID-19 pandemic and discuss how it has affected my hometown of El Paso, Texas.Media Rise Publications. Quarantined Across Borders Collection. Edited by Dr Srividya "Srivi" Ramasubramanian

Electromagnetic Evidence that SSS17a is the Result of a Binary Neutron Star Merger

11 hours after the detection of gravitational wave source GW170817 by the Laser Interferometer Gravitational-Wave Observatory and Virgo Interferometers, an associated optical transient SSS17a was discovered in the galaxy NGC 4993. While the gravitational wave data indicate GW170817 is consistent with the merger of two compact objects, the electromagnetic observations provide independent constraints of the nature of that system. Here we synthesize all optical and near-infrared photometry and spectroscopy of SSS17a collected by the One-Meter Two-Hemisphere collaboration. We find that SSS17a is unlike other known transients. The source is best described by theoretical models of a kilonova consisting of radioactive elements produced by rapid neutron capture (the r-process). We find that SSS17a was the result of a binary neutron star merger, reinforcing the gravitational wave result.Comment: 21 pages, 4 figures, accepted to Scienc