Grammar Variational Autoencoder

Deep generative models have been wildly successful at learning coherent latent representations for continuous data such as video and audio. However, generative modeling of discrete data such as arithmetic expressions and molecular structures still poses significant challenges. Crucially, state-of-the-art methods often produce outputs that are not valid. We make the key observation that frequently, discrete data can be represented as a parse tree from a context-free grammar. We propose a variational autoencoder which encodes and decodes directly to and from these parse trees, ensuring the generated outputs are always valid. Surprisingly, we show that not only does our model more often generate valid outputs, it also learns a more coherent latent space in which nearby points decode to similar discrete outputs. We demonstrate the effectiveness of our learned models by showing their improved performance in Bayesian optimization for symbolic regression and molecular synthesis

Studies of Hadronization Mechanisms using Pion Electroproduction in Deep Inelastic Scattering from Nuclei

Atomic nuclei can be used as spatial analyzers of the hadronization process in semi-inclusive deep inelastic scattering. The study of this process using fully-identified final state hadrons began with the HERMES program in the late 1990s, and is now continuing at Jefferson Lab. In the measurement described here, electrons and positive pions were measured from a 5 GeV electron beam incident on targets of liquid deuterium, C, Fe, and Pb using CLAS in Hall B. The broadening of the transverse momentum of positive pions has been studied in detail as a function of multiple kinematic variables, and interpreted in terms of the transport of the struck quark through the nuclear systems. New insights are being obtained into the hadronization process from these studies; and experiments of this type can be relevant for the interpretation of jet quenching and proton-nucleus collisions at RHIC and LHC. These measurements will be extended in the next few years with the approved JLab experiment E12-06-117, and later at a future Electron-Ion Collider.Comment: 3 pages, 2 figures; proceedings of the 19th Particles & Nuclei International Conference (PANIC), 2011, with one updated figur

A Critical Review onMathematical Descriptions to Study Flux Processes and Environmental-Related Interactions ofMangroves

Trees are resources that provide multiple benefits, such as the conservation of fauna, both terrestrial and marine, a source of food and raw material, and offering protection in storms, which makes it practical to understand their behavior against different phenomena. Such understanding may be possible through process modeling. Studies confirm that mangrove forests can store more carbon than other forests, influencing the fight against global warming. Thus, a critical and systematic review was carried out regarding studies focusing on mangroves to collect information on the models that have been applied and the most influential variables highlighted by other authors. Applying a systematic search for the most relevant topics related to mangroves (basic as well as recent information), it is possible to group models and methods carried out by other authors to respond to certain behaviors presented by mangroves. Moreover, possible structuring of a mathematical model applied to a species of interest thanks to the analyzed references could provide justified information to the authorities on the importance of these forests and the benefits of their preservation and regeneration-recovery.Trees are resources that provide multiple benefits, such as the conservation of fauna, both terrestrial and marine, a source of food and raw material, and offering protection in storms, which makes it practical to understand their behavior against different phenomena. Such understanding may be possible through process modeling. Studies confirm that mangrove forests can store more carbon than other forests, influencing the fight against global warming. Thus, a critical and systematic review was carried out regarding studies focusing on mangroves to collect information on the models that have been applied and the most influential variables highlighted by other authors. Applying a systematic search for the most relevant topics related to mangroves (basic as well as recent information), it is possible to group models and methods carried out by other authors to respond to certain behaviors presented by mangroves. Moreover, possible structuring of a mathematical model applied to a species of interest thanks to the analyzed references could provide justified information to the authorities on the importance of these forests and the benefits of their preservation and regeneration-recovery

Thermal modelling of Advanced LIGO test masses

High-reflectivity fused silica mirrors are at the epicentre of current advanced gravitational wave detectors. In these detectors, the mirrors interact with high power laser beams. As a result of finite absorption in the high reflectivity coatings the mirrors suffer from a variety of thermal effects that impact on the detectors performance. We propose a model of the Advanced LIGO mirrors that introduces an empirical term to account for the radiative heat transfer between the mirror and its surroundings. The mechanical mode frequency is used as a probe for the overall temperature of the mirror. The thermal transient after power build-up in the optical cavities is used to refine and test the model. The model provides a coating absorption estimate of 1.5 to 2.0 ppm and estimates that 0.3 to 1.3 ppm of the circulating light is scattered on to the ring heater.Comment: 14 pages, 9 figure

Influencia de diferentes niveles de Nitrógeno combinado y sin combinar con Glomus Fasciculatum sobre el cultivo de Tomate (Original)

The tomato cultivation is the great economical importance on the world.  In the present work the use of the mycorrhizal fungi and the nitrogenated fertilization in the growth, nutrition and yield of tomato (Solanum lycopersicum, Lin.)  variety Vyta  were carried out. The experiment in field with a randomly blocks design with 8 treatments and 4 replicate at Cautillo's locality in Jiguaní municipality belonging Granma province were executed. In these experiment was combined Glomus fasciculatum with the 60% and 75% of nitrogen indicated for this cultivation and phosphorus and a fixed bottom of potassium and phosphorus were compared. The results evidenced the effectiveness of strains of Glomus fasciculatum over yields on ganvisol chromic soil. The system optimization with the reduction of 40% of the nitrogen and an yield increase over of the doses taken as reference.El cultivo del tomate es de gran importancia económica a nivel mundial. El presente trabajo se realizó con el objetivo de evaluar la utilización de los hongos micorrizógenos arbusculares y la fertilización nitrogenada en el crecimiento, la nutrición y el rendimiento del tomate (Solanum lycopersicum, Lin.) variedad Vyta. Se desarrolló un experimento de campo con un diseño en bloques al azar con 8 tratamientos y 4 réplicas en la localidad de Cautillo, municipio de Jiguaní en la provincia de Granma. Se combinó la cepa Glomus fasciculatum con el 60% y el 75% del nitrógeno recomendado para este cultivo y un fondo fijo de fósforo y potasio. Los resultados mostraron la efectividad de la cepa Glomus fasciculatum sobre el rendimiento en un suelo Fersialítico Pardo Rojizo. Se logró la reducción de un 40% del nitrógeno y un incremento de los rendimientos por encima de las dosis tomadas como referencia

Executive Summary of Propulsion on the Orion Abort Flight-Test Vehicles

The National Aeronautics and Space Administration Orion Flight Test Office was tasked with conducting a series of flight tests in several launch abort scenarios to certify that the Orion Launch Abort System is capable of delivering astronauts aboard the Orion Crew Module to a safe environment, away from a failed booster. The first of this series was the Orion Pad Abort 1 Flight-Test Vehicle, which was successfully flown on May 6, 2010 at the White Sands Missile Range in New Mexico. This report provides a brief overview of the three propulsive subsystems used on the Pad Abort 1 Flight-Test Vehicle. An overview of the propulsive systems originally planned for future flight-test vehicles is also provided, which also includes the cold gas Reaction Control System within the Crew Module, and the Peacekeeper first stage rocket motor encased within the Abort Test Booster aeroshell. Although the Constellation program has been cancelled and the operational role of the Orion spacecraft has significantly evolved, lessons learned from Pad Abort 1 and the other flight-test vehicles could certainly contribute to the vehicle architecture of many future human-rated space launch vehicle

Genome variations: Effects on the robustness of neuroevolved control for swarm robotics systems

Manual design of self-organized behavioral control for swarms of robots is a complex task. Neuroevolution has proved a viable alternative given its capacity to automatically synthesize controllers. In this paper, we introduce the concept of Genome Variations (GV) in the neuroevolution of behavioral control for robotic swarms. In an evolutionary setup with GV, a slight mutation is applied to the evolving neural network parameters before they are copied to the robots in a swarm. The genome variation is individual to each robot, thereby generating a slightly heterogeneous swarm. GV represents a novel approach to the evolution of robust behaviors, expected to generate more stable and robust individual controllers, and bene t swarm behaviors that can deal with small heterogeneities in the behavior of other members in the swarm. We conduct experiments using an aggregation task, and compare the evolved solutions to solutions evolved under ideal, noise-free conditions, and to solutions evolved with traditional sensor noise.info:eu-repo/semantics/acceptedVersio

Relationship between fatigue, physical activity and health-related factors in COPD

Fatigue is highly prevalent in COPD and may be associated with reduced physical activity (PA) and poor outcomes. This study explored the relationship between fatigue, objectively measured PA and health-related factors in people with COPD. Fatigue was assessed with the Checklist of Individual Strength (CIS20) and CIS20-Subjective Fatigue (CIS20-SF) and PA with Actigraph GT3X monitors (moderate-to-vigorous PA, MVPA; total PA; steps/day). Dyspnoea (modified Medical Research Council, mMRC), exercise tolerance (6-min walk distance, 6MWD), lung function (spirometry) and GOLD A-D were collected. Spearman (ρ) and Pearson (r) correlations and multiple regressions were performed. Variables entered the model if correlation≥0.2. 54 patients participated (68±7 years; 82% men) and 69% reported fatigue (CIS20-SF≥27). Fatigue was significantly correlated with MVPA, steps/day, mMRC, 6MWD, GOLD A-D and FEV1pp (Table 1). In regression models for CIS20 (p=.001; r2=.61) and CIS20-SF (p=.003; r2=.56), dyspnoea was the only significant variable. People with higher scores of fatigue present lower PA levels, although the relationship is weak. Dyspnoea appears to have the largest influence on fatigue.info:eu-repo/semantics/publishedVersio