Generation of bipartite spin entanglement via spin-independent scattering

We consider the bipartite spin entanglement between two identical fermions generated in spin-independent scattering. We show how the spatial degrees of freedom act as ancillas for the creation of entanglement to a degree that depends on the scattering angle, $\theta$. The number of Slater determinants generated in the process is greater than 1, corresponding to genuine quantum correlations between the identical fermions. The maximal entanglement attainable of 1 ebit is reached at $\theta=\pi/2$. We also analyze a simple $\theta$ dependent Bell's inequality, which is violated for $\pi/4<\theta\leq\pi/2$. This phenomenon is unrelated to the symmetrization postulate but does not appear for unequal particles.Comment: 5 pages and 3 figures. Accepted in PR

Analysis of the power balance In the cells of a multilevel cascaded H-Bridge converter

Multilevel cascaded H-Bridge converters (CHB) have been presented as a good solution for high power applications. In this way, several control and modulation techniques have been proposed for this power converter topology. In this paper the steady state power balance in the cells of the single phase two cell CHB is studied. The capability to be supplied with active power from the grid or to deliver active power to the grid in each cell is analyzed according to the dc-link voltages and the desired ac output voltage value. Limits of the maximum and minimum input active power for stable operation of the CHB are addressed. Simulation results are shown to validate the presented analysis

Musgos de turberas en la Isla Grande de Chiloé - Chile: claves para identificación

Los briófitos juegan un rol clave en las turberas. Sin embargo, el conocimiento de este grupo es escaso en el sur deSudamérica. Se presenta una clave de identificación de musgos de turberas de la Isla Grande de Chiloé (Chile). La claveestá separada para cada grupo con caracteres similares.Los briófitos juegan un rol clave en las turberas. Sin embargo, el conocimiento de este grupo es escaso en el sur deSudamérica. Se presenta una clave de identificación de musgos de turberas de la Isla Grande de Chiloé (Chile). La claveestá separada para cada grupo con caracteres similares

Mechanisms of Contextual Control when Contexts are Informative to Solve the Task

An experiment was conducted using a human instrumental learning task with the goal of evaluating the mechanisms underlying the deleterious effect of context-switching on responding to an unambiguous stimulus when contexts are informative to solve the task. Participants were trained in a context-based reversal discrimination in which two discriminative stimuli (X and Y) interchange their meaning across contexts A and B. In context A, discriminative stimulus Z consistently announced that the relationship between a specific instrumental response (R1) and a specific outcome (O1) was in effect. Performance in the presence of stimulus Z was equally deteriorated when the test was conducted outside the training context, regardless of whether the test context was familiar (context B) or new (context C). This result is consistent with the idea that participants code all the information presented in an informative context as context-specific with the context playing a role akin to an occasion setter

Roles of context in acquisition of human instrumental learning: Implications for the understanding of the mechanisms underlying context-switch effects

Four experiments in human instrumental learning explored the associations involving the context that develop after three trials of training on simple discriminations. Experiments 1 and 4 found a deleterious effect of switching the learning context that cannot be explained by the context-outcome binary associations commonly used to explain context-switch effects after short training in human predictive learning and in animal Pavlovian conditioning. Evidence for context-outcome (Experiment 2), context-discriminative stimulus (Experiment 3), and context-instrumental response (Experiment 4) binary associations was found within the same training paradigm, suggesting that contexts became associated with all the elements of the situation, regardless of whether those associations played a role in a specific context-switch effect detected on performance.This research was funded by Grants PSI2010-15215 from the Spanish Ministry of Science and Innovation, and PSI2014-52263-C2-1-P from the Spanish Ministry of Economy and Competitiveness

Furnariidae species recognition using speech-related features and machine learning

The automatic classification of calling bird species is important to achieve more exhaustive environmental monitoring and to manage natural resources. Bird vocalizations allow to recognise new species, their natural history and macro-systematic relations, while automatic systems can speed up and improve all the process. In this work, we use state-of-art features designed for speech and speaker state recognition to classify 25 species of Furnariidae family. Since Furnariidae species inhabit the Litoral Paranaense region of Argentina (South America), this work could promote further research on the topic and the implementation of in-situ monitoring systems. Our analysis includes two widely-known classification techniques: random forest an support vector machines. The results are promising, near 86%, and were validated in a cross-validation scheme.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Feed-forward Space Vector Modulation for Single-Phase Multilevel Cascade Converters with any DC voltage ratio

Modulation techniques for multilevel converters can create distorted output voltages and currents if the DC link voltages are unbalanced. This situation can be avoided if the instantaneous DC voltage error is not taken into account in the modulation process. This paper proposes a feed-forward space vector modulation method for a single-phase multilevel cascade converter. Using this modulation technique, the modulated output voltage of the power converter always generates the reference determined by the controller even in worst case voltage unbalance conditions. In addition the possibility of optimizing the DC voltage ratio between the H-bridges of the power converter is introduced. Experimental results from a 5kVA prototype are presented in order to validate the proposed modulation technique

Low temperature processing of baroplastic core-shell nanoparticles and block copolymers

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, February 2006.Includes bibliographical references (p. 131-144).Baroplastics are nanophase polymeric materials comprised of two components that can miscibilize under pressure thereby facilitating flow. The possibility of processing these materials at low temperatures was the main focus of this work. Block copolymer baroplastics comprised of a low Tg and a high Tg component that microphase separate, such as polystyrene-block-poly(butyl acrylate) (PS-b-PBA) and polystyrene-b-poly(2-ethyl hexylacrylate) (PS-b-PEHA), were synthesized by ATRP and processed at reduced temperatures by compression molding. The resulting processed specimens were clear and well-defined solid objects. Structural characterization studies on the processed baroplastics showed that the mixing between components during processing is incomplete and distinct hard and soft domains are present even after multiple processing cycles. This suggests that the processing is of a semi-solid nature, where the rigid PS domains are mobilized by the low Tg component. Processing of a control sample exhibiting pressure-induced demixing, polystyrene-block-poly(lauryl methacrylate) (PS-b-PLMA), yielded incompletely processed objects under the same processing conditions and inferior mechanical properties to its acrylate counterparts.(cont.) Low temperature processing of baroplastics and the proposed semi-solid processing mechanism were further demonstrated with the study of core-shell nanoparticles, where the soft homopolymer (PBA or PEHA) formed the core surrounded by a rigid PS shell. These materials could also be processed at reduced temperatures, displaying a wide range of mechanical properties as a function of their composition, going from tough and rigid materials to soft and rubbery ones comparable to commercial thermoplastic elastomers. Low temperature processing of baroplastics opens a new route to polymer processing, where energy for heating and cooling could be saved, processing times could be reduced and materials with high sensitivity to temperature could be processed.by Juan A González-León.Ph.D