1,550 research outputs found
Approximate entropy and auto mutual information analysis of the electroencephalogram in Alzheimer's disease patients
Microwave Spectroscopy
Contains research objectives, reports on work completed and one research project.Joint Services Electronics Programs (U. S. Army, U.S. Navy, and U.S. Air Force) under Contract DA 28-043-AMC-02536(E
Analysis of electroencephalograms in Alzheimer's disease patients with multiscale entropy
The aim of this study was to analyse the electroencephalogram (EEG) background activity of Alzheimer’s disease (AD) patients using the Multiscale Entropy (MSE). The MSE is a recently developed method that quantifies the regularity of a signal on different time scales. These time scales are inspected by means of several coarse-grained sequences formed from the analysed signals. We recorded the EEGs from 19 scalp electrodes in 11 AD patients and 11 age-matched controls and estimated the MSE profile for each epoch of the EEG recordings. The shape of the MSE profiles reveals the EEG complexity, and it suggests that the EEG contains information in deeper scales than the smallest one. Moreover, the results showed that the EEG background activity is less complex in AD patients than control subjects. We found significant difference
The test of Random Rhythm Generation and neuropsychological performance in schizophrenic patients
Producción CientíficaThe objective of this study was the assessment of neuropsychological performance in a sample of schizophrenic patients using a new computer-administered instrument, the Test of Random Rhythm Generation (ARG). The test was applied to a group of 20 DSM-IV schizophrenic patients (SG) and 20 sex- and age-matched controls (CG). The Positive and Negative Syndrome Scale (PANSS) and Frankfurt Complaint Questionnaire (Frankfurter Beschwerdefragebogen, FBF) were used to study patients' psychopathology. The neuroleptic treatment received by each patient during the last month was converted into daily equivalents of chlorpromazine. In the ARG, the subject is asked to press the space key of the computer at a rhythm as irregular as possible. The test aims at assessing the individual's ability to create random rhythms by means of sequences of blows, which is hypothetically associated with a high neuropsychological performance. The data were analyzed by means of three different mathematical techniques. Results showed that schizophrenic patients generated more regular and rhythmic sequences than controls (correlation dimension in SG = 2.78 +/- 0.81, in CG = 3.69 +/- 0.64, p < 0.01). This suggests that neuropsychological performance measured by the ARG was worse in patients compared to controls. ARG is proposed as a new technique to evaluate neuropsychological performance with the following advantages: (1) its short-time application tit usually takes no more than 10 minutes), (2) personnel only require a short training to learn how to apply it, and (3) different analyses of the data are quickly carried out by the computer program
SHARDS: Constraints on the dust attenuation law of star-forming galaxies at z~2
We make use of SHARDS, an ultra-deep (<26.5AB) galaxy survey that provides
optical photo-spectra at resolution R~50, via medium band filters (FWHM~150A).
This dataset is combined with ancillary optical and NIR fluxes to constrain the
dust attenuation law in the rest-frame NUV region of star-forming galaxies
within the redshift window 1.5<z<3. We focus on the NUV bump strength (B) and
the total-to-selective extinction ratio (Rv), targeting a sample of 1,753
galaxies. By comparing the data with a set of population synthesis models
coupled to a parametric dust attenuation law, we constrain Rv and B, as well as
the colour excess, E(B-V). We find a correlation between Rv and B, that can be
interpreted either as a result of the grain size distribution, or a variation
of the dust geometry among galaxies. According to the former, small dust grains
are associated with a stronger NUV bump. The latter would lead to a range of
clumpiness in the distribution of dust within the interstellar medium of
star-forming galaxies. The observed wide range of NUV bump strengths can lead
to a systematic in the interpretation of the UV slope () typically used
to characterize the dust content. In this study we quantify these variations,
concluding that the effects are ~0.4.Comment: 13 pages, 11+2 figures, 3 tables. MNRAS, in pres
Quantitative trait loci of stripe rust resistance in wheat
KEY MESSAGE: Over 140 QTLs for resistance to stripe rust in wheat have been published and through mapping flanking markers on consensus maps, 49 chromosomal regions are identified. ABSTRACT: Over thirty publications during the last 10 years have identified more than 140 QTLs for stripe rust resistance in wheat. It is likely that many of these QTLs are identical genes that have been spread through plant breeding into diverse backgrounds through phenotypic selection under stripe rust epidemics. Allelism testing can be used to differentiate genes in similar locations but in different genetic backgrounds; however, this is problematic for QTL studies where multiple loci segregate from any one parent. This review utilizes consensus maps to illustrate important genomic regions that have had effects against stripe rust in wheat, and although this methodology cannot distinguish alleles from closely linked genes, it does highlight the extent of genetic diversity for this trait and identifies the most valuable loci and the parents possessing them for utilization in breeding programs. With the advent of cheaper, high throughput genotyping technologies, it is envisioned that there will be many more publications in the near future describing ever more QTLs. This review sets the scene for the coming influx of data and will quickly enable researchers to identify new loci in their given populations
Multimodality of rich clusters from the SDSS DR8 within the supercluster-void network
We study the relations between the multimodality of galaxy clusters drawn
from the SDSS DR8 and the environment where they reside. As cluster environment
we consider the global luminosity density field, supercluster membership, and
supercluster morphology. We use 3D normal mixture modelling, the
Dressler-Shectman test, and the peculiar velocity of cluster main galaxies as
signatures of multimodality of clusters. We calculate the luminosity density
field to study the environmental densities around clusters, and to find
superclusters where clusters reside. We determine the morphology of
superclusters with the Minkowski functionals and compare the properties of
clusters in superclusters of different morphology. We apply principal component
analysis to study the relations between the multimodality parametres of
clusters and their environment simultaneously. We find that multimodal clusters
reside in higher density environment than unimodal clusters. Clusters in
superclusters have higher probability to have substructure than isolated
clusters. The superclusters can be divided into two main morphological types,
spiders and filaments. Clusters in superclusters of spider morphology have
higher probabilities to have substructure and larger peculiar velocities of
their main galaxies than clusters in superclusters of filament morphology. The
most luminous clusters are located in the high-density cores of rich
superclusters. Five of seven most luminous clusters, and five of seven most
multimodal clusters reside in spider-type superclusters; four of seven most
unimodal clusters reside in filament-type superclusters. Our study shows the
importance of the role of superclusters as high density environment which
affects the properties of galaxy systems in them.Comment: 16 pages, 12 figures, 2 online tables, accepted for publication in
Astronomy and Astrophysic
From Multiview Image Curves to 3D Drawings
Reconstructing 3D scenes from multiple views has made impressive strides in
recent years, chiefly by correlating isolated feature points, intensity
patterns, or curvilinear structures. In the general setting - without
controlled acquisition, abundant texture, curves and surfaces following
specific models or limiting scene complexity - most methods produce unorganized
point clouds, meshes, or voxel representations, with some exceptions producing
unorganized clouds of 3D curve fragments. Ideally, many applications require
structured representations of curves, surfaces and their spatial relationships.
This paper presents a step in this direction by formulating an approach that
combines 2D image curves into a collection of 3D curves, with topological
connectivity between them represented as a 3D graph. This results in a 3D
drawing, which is complementary to surface representations in the same sense as
a 3D scaffold complements a tent taut over it. We evaluate our results against
truth on synthetic and real datasets.Comment: Expanded ECCV 2016 version with tweaked figures and including an
overview of the supplementary material available at
multiview-3d-drawing.sourceforge.ne
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