1,661 research outputs found
Factors of Influence on the Performance of a Short-Latency Non-Invasive Brain Switch: Evidence in Healthy Individuals and Implication for Motor Function Rehabilitation.
Brain-computer interfacing (BCI) has recently been applied as a rehabilitation approach for patients with motor disorders, such as stroke. In these closed-loop applications, a brain switch detects the motor intention from brain signals, e.g., scalp EEG, and triggers a neuroprosthetic device, either to deliver sensory feedback or to mimic real movements, thus re-establishing the compromised sensory-motor control loop and promoting neural plasticity. In this context, single trial detection of motor intention with short latency is a prerequisite. The performance of the event detection from EEG recordings is mainly determined by three factors: the type of motor imagery (e.g., repetitive, ballistic), the frequency band (or signal modality) used for discrimination (e.g., alpha, beta, gamma, and MRCP, i.e., movement-related cortical potential), and the processing technique (e.g., time-series analysis, sub-band power estimation). In this study, we investigated single trial EEG traces during movement imagination on healthy individuals, and provided a comprehensive analysis of the performance of a short-latency brain switch when varying these three factors. The morphological investigation showed a cross-subject consistency of a prolonged negative phase in MRCP, and a delayed beta rebound in sensory-motor rhythms during repetitive tasks. The detection performance had the greatest accuracy when using ballistic MRCP with time-series analysis. In this case, the true positive rate (TPR) was ~70% for a detection latency of ~200 ms. The results presented here are of practical relevance for designing BCI systems for motor function rehabilitation
Gasterópodos marinos de las islas Columbretes (Mediterráneo occidental).
Se estudian varias muestras de sedimentos bioclásticos recogidas con escafandra autónoma en distintos puntos de las islas Columbretes. Como resultado se obtuvieron un total de 257 especies de gasterópodos, de las cuales 119 constituyen nuevas citas para este enclave insular y una del género Crisilla se describe como nueva para la ciencia. Se comentan los problemas taxonómicos que presentan diversas especies de los géneros Dikoleps, Crisilla, Chauvetia y Cima, o de las familias Cerithiopsidae y Omalogyridae. Por último, se ofrecen unas consideraciones generales sobre la malacofauna marina de estas islas.Agradecemos a Emilio Rolán, Anselmo Peñas, Serge Gofas, Marian Ramos (Investigadora Principal del Proyecto Fauna Ibérica) y a Javier de Andrés y Rafael Araujo (colección de malacología del MNCN) el habernos facilitado material de comparación. Las fotografías al SEM se han realizado en el Servicio de Microscopía Electrónica, a cargo de Laura Tormo, Marta Furió y Alberto Jorge, y gracias a la financiación del proyecto CGL2007-60954 del Ministerio de Educación y Ciencia. A la Secretaría General del Mar, organismo gestor de la Reserva Marina de las islas Columbretes, agradecemos su constante apoyo a la investigación en las islas. Por último, los comentarios de Serge Gofas han contribuido a mejorar considerablemente la versión final de este artículo.Peer Reviewe
Causal Consistency of Structural Equation Models
Complex systems can be modelled at various levels of detail. Ideally, causal
models of the same system should be consistent with one another in the sense
that they agree in their predictions of the effects of interventions. We
formalise this notion of consistency in the case of Structural Equation Models
(SEMs) by introducing exact transformations between SEMs. This provides a
general language to consider, for instance, the different levels of description
in the following three scenarios: (a) models with large numbers of variables
versus models in which the `irrelevant' or unobservable variables have been
marginalised out; (b) micro-level models versus macro-level models in which the
macro-variables are aggregate features of the micro-variables; (c) dynamical
time series models versus models of their stationary behaviour. Our analysis
stresses the importance of well specified interventions in the causal modelling
process and sheds light on the interpretation of cyclic SEMs.Comment: equal contribution between Rubenstein and Weichwald; accepted
manuscrip
Theory of Exciton Migration and Field-Induced Dissociation in Conjugated Polymers
The interplay of migration, recombination, and dissociation of excitons in
disordered media is studied theoretically in the low temperature regime. An
exact expression for the photoluminescence spectrum is obtained. The theory is
applied to describe the electric field-induced photoluminescence-quenching
experiments by Kersting et al. [Phys. Rev. Lett. 73, 1440 (1994)] and Deussen
et al. [Synth. Met. 73, 123 (1995)] on conjugated polymer systems. Good
agreement with experiment is obtained using an on-chain dissociation mechanism,
which implies a separation of the electron-hole pair along the polymer chain.Comment: 4 pages, RevTeX, 2 Postscript figure
Isothermal Recombinase Polymerase amplification (RPA) of Schistosoma haematobium DNA and oligochromatographic lateral flow detection
© 2015 Rosser et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The attached file is the published version of the article
Environmental drivers of distribution and reef development of the Mediterranean coral Cladocora caespitosa
Cladocora caespitosa is the only Mediterranean scleractinian similar to tropical reef-building corals. While this species is part of the recent fossil history of the Mediterranean Sea, it is currently considered endangered due to its decline during the last decades. Environmental factors affecting the distribution and persistence of extensive bank reefs of this endemic species across its whole geographic range are poorly understood. In this study, we examined the environmental response of C. caespitosa and its main types of assemblages using ecological niche modeling and ordination analysis. We also predicted other suitable areas for the occurrence of the species and assessed the conservation effectiveness of Mediterranean marine protected areas (MPAs) for this coral. We found that phosphate concentration and wave height were factors affecting both the occurrence of this versatile species and the distribution of its extensive bioconstructions in the Mediterranean Sea. A set of factors (diffuse attenuation coefficient, calcite and nitrate concentrations, mean wave height, sea surface temperature, and shape of the coast) likely act as environmental barriers preventing the species from expansion to the Atlantic Ocean and the Black Sea. Uncertainties in our large-scale statistical results and departures from previous physiological and ecological studies are also discussed under an integrative perspective. This study reveals that Mediterranean MPAs encompass eight of the ten banks and 16 of the 21 beds of C. caespitosa. Preservation of water clarity by avoiding phosphate discharges may improve the protection of this emblematic species.Spanish Ministry of Economy and Competitiveness [CTM2014-57949-R]info:eu-repo/semantics/publishedVersio
Defect distribution in a-plane GaN on Al2O3
The authors studied the structural and point defect distributions of hydride vapor phase epitaxial GaN film grown in the [11−20] a direction on (1−102) r-plane sapphire with metal-organic vapor phase deposited a-GaN template using transmission electron microscopy, secondary ion mass spectrometry, and positron annihilation spectroscopy. Grown-in extended and point defects show constant behavior as a function of thickness, contrary to the strong nonuniform defect distribution observed in GaN grown along the [0001] direction. The observed differences are explained by orientation-dependent and kinetics related defect incorporation.Peer reviewe
Flavor Alignment in SUSY GUTs
A Supersymmetric Grand unified model is constructed based on SO(10)xSO(10)
symmetry in which new types of Yukawa matrices couple standard and exotic
fermions. Evolution of these couplings from the Grand Unified scale to the
electroweak scale causes some of them to be driven to their fixed points. This
solves the supersymmetric alignment problem and ensures that there are no
observable flavor changing neutral currents mediated by supersymmetric
particles. Fermion hierarchy and neutrino mixing constraints are automatically
satisfied in this formalism.Comment: 20 pages, 1 figur
CP violation from noncommutative geometry
If the geometry of space-time is \nc, i.e. , then \nc \cpviolng effects may be manifest at low energies. For a
\nc scale , \cpviol from \ncg is
comparable to that from the Standard Model (SM) alone: the \nc contributions
to and in the -system, may actually dominate
over the Standard Model contributions. Present data permit \ncg to be the
only source of \cpviol. Furthermore the most recent findings for g-2 of the
muon are consistent with predictions from \ncg. If the geometry of space-time
is \nc, , then \nc \cpviolng
effects may be manifest at low energies. For a \nc scale , \cpviol from \ncg is comparable to that from the
Standard Model (SM) alone: the \nc contributions to and
in the K-system, may actually dominate over the Standard
Model contributions. Present data permit \ncg to be the only source of
\cpviol. Furthermore the most recent findings for g-2 of the muon are
consistent with predictions from \ncg.Comment: fixed notation, corrected some typo
Review of the Phenomenology of Noncommutative Geometry
We present a pedagogical review of particle physics models that are based on
the noncommutativity of space-time, , with specific attention to the phenomenology these models predict in
particle experiments either in existence or under development. We summarize
results obtained for high energy scattering such as would occur for example in
a future linear collider with , as well as low
energy experiments such as those pertaining to elementary electric dipole
moments and other \cpviolng observables, and finally comment on the status of
phenomenological work in cosmology and extra dimensions.Comment: updated, references added, corrected typo
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