2,220 research outputs found
Non-monotonic entanglement of physical EM field states in non-inertial frames
We develop a general technique to analyse the quantum effects of acceleration
on realistic spatially-localised electromagnetic field states entangled in the
polarization degree of freedom. We show that for this setting, quantum
entanglement may build up as the acceleration increases, providing a clear
signature of the quantum effects of relativistic acceleration.Comment: 5 pages, 3 figure
Population bound effects on bosonic correlations in non-inertial frames
We analyse the effect of bounding the occupation number of bosonic field
modes on the correlations among all the different spatial-temporal regions in a
setting in which we have a space-time with a horizon along with an inertial
observer. We show that the entanglement between A (inertial observer) and R
(uniformly accelerated observer) depends on the bound N, contrary to the
fermionic case. Whether or not decoherence increases with N depends on the
value of the acceleration a. Concerning the bipartition A-antiR (Alice with an
observer in Rindler's region IV), we show that no entanglement is created
whatever the value of N and a. Furthermore, AR entanglement is very quickly
lost for finite N and for infinite N. We will study in detail the mutual
information conservation law found for bosons and fermions. By means of the
boundary effects associated to N finiteness, we will show that for bosons this
law stems from classical correlations while for fermions it has a quantum
origin. Finally, we will present the strong N dependence of the entanglement in
R-antiR bipartition and compare the fermionic cases with their finite N bosonic
analogs. We will also show the anti-intuitive dependence of this entanglement
on statistics since more entanglement is created for bosons than for their
fermion counterparts.Comment: revtex 4, 12 pages, 10 figures. Added Journal ref
Unveiling quantum entanglement degradation near a Schwarzschild black hole
We analyze the entanglement degradation provoked by the Hawking effect in a
bipartite system Alice-Rob when Rob is in the proximities of a Schwarzschild
black hole while Alice is free falling into it. We will obtain the limit in
which the tools imported from the Unruh entanglement degradation phenomenon can
be used properly, keeping control on the approximation. As a result, we will be
able to determine the degree of entanglement as a function of the distance of
Rob to the event horizon, the mass of the black hole, and the frequency of
Rob's entangled modes. By means of this analysis we will show that all the
interesting phenomena occur in the vicinity of the event horizon and that the
presence of event horizons do not effectively degrade the entanglement when Rob
is far off the black hole. The universality of the phenomenon is presented:
There are not fundamental differences for different masses when working in the
natural unit system adapted to each black hole. We also discuss some aspects of
the localization of Alice and Rob states. All this study is done without using
the single mode approximation.Comment: 16 pages, 10 figures, revtex4. Added Journal referenc
Comparative Analysis of Parallel Brain Activity Mapping Algorithms for High Resolution Brain Models
En este artÃculo se propone un análisis comparativo entre versiones regulares y en paralelo de métodos de optimización FISTA y Tikhonov, para resolver el problema de mapeo cerebral a partir de EEG. La comparación se realiza en términos de la reducción del tiempo computacional y el error de estimación obtenido por los métodos paralelizados. Dos modelos de cabeza con alta y baja resolución son usados para la comparación de los algoritmos. Como resultado se puede ver que, si el número de procesos en paralelo se incrementa, el tiempo computacional disminuye significativamente para todos los modelos de cabeza, sin comprometer la calidad de la reconstrucción. Adicionalmente, se puede concluir que el uso de un modelo de cabeza de alta resolución resulta en una mejora de cualquier método de reconstrucción en términos de la resolución espacial.This paper proposes a comparative analysis between regular and parallel versions of FISTA and Tikhonov-like optimizations for solving the EEG brain mapping problem. Such comparison is performed in terms of computational time reduction and estimation error achieved by the parallelized methods. Two brain models (high- and low-resolution) are used to compare the algorithms. As a result, it can be seen that, if the number of parallel processes increases, computational time decreases significantly for all the head models used in this work, without compromising the reconstruction quality. In addition, it can be concluded that the use of a high-resolution head model produces an improvement in any source reconstruction method in terms of spatial resolution.
Liquid fuels from biomass: An energy self-sustained process integrating H2 recovery and liquid refining
[EN] In the last years the research activities on biomass valorisation (mainly residues from urban and agricultural activities) have been intensified. Biomass is an abundant resource for energy generation and its extensive utilization may make possible to fulfil the goals determined by the national and international regulations about renewable sources and greenhouse gas emissions. In this work, simulations are carried out using ASPEN PLUS for an integrated process to produce liquid fuels from biomass in a self-sustainable energetic regime (thermal and electric) and several process factors have been considered. The process initially combines a primary pyrolysis reactor associated to a (char + gases) gasification unit in order to optimize the biomass use, followed by downstream processes to enhance the quality of final liquid fuel. The factors studied were the composition of the biomass, the primary (or pyrolytic) liquid yield, the composition of the liquid fuel, as well as the amount of the oxidant and steam used in the primary char-gasifier reactor. The use of a simplified model for liquid fuel composition let us to stablish a range of operational conditions in which both thermal and electric balance of the process are favourable. In this sense, the maximum extraction of liquid fuel was found around 20-25% by working at 10-25% of O-2 (as pure oxygen or air) and 15-45% of steam in the gasifier and fulfilling self-sustainable process condition, while biomass should possess C/O weight ratios >= 1.Financial support by the Spanish Government (ENE2014-57651, CTQ2015-67592, and SEV-2016-0683 grants) is gratefully acknowledged.D. Catalán-MartÃnez; Domine ., ME.; Serra Alfaro, JM. (2018). Liquid fuels from biomass: An energy self-sustained process integrating H2 recovery and liquid refining. Fuel. 212:353-363. https://doi.org/10.1016/j.fuel.2017.10.014S35336321
Teaching english through multisensory activities in a public school
El presente proyecto fue llevado a cabo en una institución pública mixta en el municipio de Dosquebradas, Colombia con el fin de aplicar, verificar y advocar la utilidad de la instrucción multisensorial en una o varias sesiones de una clase de lengua inglesa de grado séptimo, a través del uso estructurado de actividades especÃficamente ordenadas para ser sensorialmente estimulantes promoviendo los enlaces entre la memoria sensorial que activa la interconectividad dentro de varios canales receptores
Characterization of groups using composite kernels and multi-source fMRI analysis data: application to schizophrenia
Pattern classification of brain imaging data can enable the automatic detection of differences in cognitive processes of specific groups of interest. Furthermore, it can also give neuroanatomical information related to the regions of the brain that are most relevant to detect these differences by means of feature selection procedures, which are also well-suited to deal with the high dimensionality of brain imaging data. This work proposes the application of recursive feature elimination using a machine learning algorithm based on composite kernels to the classification of healthy controls and patients with schizophrenia. This framework, which evaluates nonlinear relationships between voxels, analyzes whole-brain fMRI data from an auditory task experiment that is segmented into anatomical regions and recursively eliminates the uninformative ones based on their relevance estimates, thus yielding the set of most discriminative brain areas for group classification. The collected data was processed using two analysis methods: the general linear model (GLM) and independent component analysis (ICA). GLM spatial maps as well as ICA temporal lobe and default mode component maps were then input to the classifier. A mean classification accuracy of up to 95% estimated with a leave-two-out cross-validation procedure was achieved by doing multi-source data classification. In addition, it is shown that the classification accuracy rate obtained by using multi-source data surpasses that reached by using single-source data, hence showing that this algorithm takes advantage of the complimentary nature of GLM and ICAPublicad
BIRD ENTANGLEMENT AND MORTALITY BY FRUITS OF THE ZAPALLO CASPI TREE PISONIA ZAPALLO IN THE DRY CHACO, ARGENTINA
Abstract ∙ Bird entanglement by plants may be globally widespread, but it is not a frequently studied phenomenon, and records in different regions of the world are still scarce. During a short visit to the El Impenetrable National Park, Chaco province, Argentina, in October–November 2022, we recorded 15 incidental cases of birds entangled or trapped by fruits of the tree Pisonia zapallo. Our report involves 12 bird species from eight families, with a wide range of body sizes and masses. To our knowledge, this is the first documented report on this phenomenon in continental South America
Poisoning by Astragalus garbancillo var. garbancillo in Sheep in Northwestern Argentina
Several toxic plants produce lysosomal storage of glycoproteins and mainly nervous clinical disorders. A disease caused by the consumption of Astragalus garbancillo var. garbancillo in sheep from northwestern Argentina is described here. The affected animals presented weight loss, listlessness, staggering gait, and ataxia. Histopathological studies revealed cellular vacuolation in several organs, mainly in the central nervous system (CNS). The material accumulated in the cells was positive for lectins LCA (Lens culinaris agglutinin), sWGA (succinyl–Triticum vulgaris agglutinin), and Con A (Concanavalin A). Finally, the presence of toxic levels of swainsonine was detected in composite samples of the plant. Poisoning by Astragalus garbancillo var. garbancillo was characterized as α-mannosidosis of plant origin.Facultad de Ciencias Veterinaria
Quantum correlations through event horizons: Fermionic versus bosonic entanglement
We disclose the behaviour of quantum and classical correlations among all the
different spatial-temporal regions of a space-time with an event horizon,
comparing fermionic with bosonic fields. We show the emergence of conservation
laws for entanglement and classical correlations, pointing out the crucial role
that statistics plays in the information exchange (and more specifically, the
entanglement tradeoff) across horizons. The results obtained here could shed
new light on the problem of information behaviour in non-inertial frames and in
the presence of horizons, giving a better insight about the black hole
information paradox.Comment: 15 pages, 8 figures, revtex 4, title changed to match journal
publication and Journal reference adde
- …