53 research outputs found
Persistent post-traumatic headache and migraine: Pre-clinical comparisons
Background: Oftentimes, persistent post traumatic headache (PPTH) and migraine are phenotypically similar and the only clinical feature that differentiate them is the presence of a mild or moderate traumatic brain injury (mTBI). The aim of this study is to describe the differences in brain area and in biochemical cascade after concussion and to define the efficacy and safety of treatments in use. Methods: Sources were chosen in according to the International Classification of Headache Disorder (ICHD) criteria. Results: The articles demonstrated a significant difference between PPTH and migraine regarding static functional connectivity (sFC) and dynamic functional connectivity (dFC) in brain structure that could be used for exploring the pathophysiological mechanisms in PPTH. Many studies described a cascade of neurometabolic changes that occur after traumatic brain injury. These variations are associated to the mechanism occurring when developing a PPTH. Conclusions: The state of art of this important topic show how although the mechanisms underlying the development of the two different diseases are different, the treatment of common migraine is efficacious in patients that have developed a post traumatic form
Discovery of Water Maser Emission in Five AGN and a Possible Correlation Between Water Maser and Nuclear 2-10 keV Luminosities
We report the discovery of water maser emission in five active galactic
nuclei (AGN) with the 100-m Green Bank Telescope (GBT). The positions of the
newly discovered masers, measured with the VLA, are consistent with the optical
positions of the host nuclei to within 1 sigma (0.3 arcsec radio and 1.3 arcsec
optical) and most likely mark the locations of the embedded central engines.
The spectra of three sources, 2MASX J08362280+3327383, NGC 6264, and UGC 09618
NED02, display the characteristic spectral signature of emission from an
edge-on accretion disk with maximum orbital velocity of ~700, ~800, and ~1300
km s^-1, respectively. We also present a GBT spectrum of a previously known
source MRK 0034 and interpret the narrow Doppler components reported here as
indirect evidence that the emission originates in an edge-on accretion disk
with orbital velocity of ~500 km s^-1. We obtained a detection rate of 12
percent (5 out of 41) among Seyfert 2 and LINER systems with 10000 km s^-1 <
v_sys < 15000 km s^-1. For the 30 nuclear water masers with available hard
X-ray data, we report a possible relationship between unabsorbed X-ray
luminosity (2-10 keV) and total isotropic water maser luminosity, L_{2-10}
proportional to L_{H2O}^{0.5+-0.1}, consistent with the model proposed by
Neufeld and Maloney in which X-ray irradiation and heating of molecular
accretion disk gas by the central engine excites the maser emission.Comment: 16 pages, 5 tables, 3 figures, to appear in the November 10, 2006,
v651n2 issue of the Astrophysical Journa
Change in hippocampal theta oscillation associated with multiple lever presses in a bimanual two-lever choice task for robot control in rats.
Hippocampal theta oscillations have been implicated in working memory and attentional process, which might be useful for the brain-machine interface (BMI). To further elucidate the properties of the hippocampal theta oscillations that can be used in BMI, we investigated hippocampal theta oscillations during a two-lever choice task. During the task body-restrained rats were trained with a food reward to move an e-puck robot towards them by pressing the correct lever, ipsilateral to the robot several times, using the ipsilateral forelimb. The robot carried food and moved along a semicircle track set in front of the rat. We demonstrated that the power of hippocampal theta oscillations gradually increased during a 6-s preparatory period before the start of multiple lever pressing, irrespective of whether the correct lever choice or forelimb side were used. In addition, there was a significant difference in the theta power after the first choice, between correct and incorrect trials. During the correct trials the theta power was highest during the first lever-releasing period, whereas in the incorrect trials it occurred during the second correct lever-pressing period. We also analyzed the hippocampal theta oscillations at the termination of multiple lever pressing during the correct trials. Irrespective of whether the correct forelimb side was used, the power of hippocampal theta oscillations gradually decreased with the termination of multiple lever pressing. The frequency of theta oscillation also demonstrated an increase and decrease, before and after multiple lever pressing, respectively. There was a transient increase in frequency after the first lever press during the incorrect trials, while no such increase was observed during the correct trials. These results suggested that hippocampal theta oscillations reflect some aspects of preparatory and cognitive neural activities during the robot controlling task, which could be used for BMI
Aggregate Selection in Evolutionary Robotics
Can the processes of natural evolution be mimicked to create robots or autonomous agents? This question embodies the most fundamental goals of evolutionary robotics (ER). ER is a field of research that explores the use of artificial evolution and evolutionary computing for learning of control in autonomous robots, and in autonomous agents in general. In a typical ER experiment, robots, or more precisely their control systems, are evolved to perform a given task in which they must interact dynamically with their environment. Controllers compete in the environment and are selected and propagated based on their ability (or fitness) to perform the desired task. A key component of this process is the manner in which the fitness of the evolving controllers is measured. In ER, fitness is measured by a fitness function or objective function. This function applies some given criteria to determine which robots or agents are better at performing the task for which they are being evolved. Fitness functions can introduce varying levels of a priori knowledge into evolving populations. Som
Post-Privatisation Corporate Performance in Poland. Evidence from Companies Privatized in 2008-2011
The study concerns the effects of Polish privatisation program conducted in the years 2008-2011. After drawing a broad picture of this process we investigate the performance of 59 privatised companies, and finally focus on a deeper analysis of three companies, which is the core part of our study. We test the hypotheses that privatisation increases a company's profitability, labour productivity, capital investment spending, plow-back ratio and leverage. In case studies, we additionally explore the effect of privatization on each company's value. The outcomes concerning the larger group of companies are partly ambiguous (with four hypotheses confirmed and four rejected). Profitability has been not visibly improved, although a number of positive initiatives and improvements in performance occurred. By contrast, the three case studies showed a significant improvement of profitability and all other performance indicators observed, as well as a considerable increase of company value. Our results show that privatisation works, though its full effects need time to occur
EMG Signals Classification on Human Activity Recognition using Machine Learning Algorithm
In Human activity recognition (HAR) research, it is a common practice to use wearable sensors to acquire the signals for human daily activities. In this study, an experimental data from electromyography (EMG) wireless sensors is analysed for six different activities recognition. This paper aims to compare EMG signals of left and right of upper leg muscles by using Random Forest (RF) Machine Learning Classifier. The HAR processing comprises of data filtering and segmentation, data feature extraction, feature selection of the data, and classification. Model evaluation of holdout method is implemented for classification assessment. The performance of all human daily activities is evaluated according to the comparison of precision and recall for each activity. The results show combined muscles obtained the highest precision and recall on running activity with 89.2% and 88.3%. The highest overall accuracy of classification was 82.08% on the bicep femoris left and right (BF-Left andamp; Right)
Sweet Taste Perception and Dental Caries in 13- to 15-Year-Olds : A Multicenter
Dietary habits and, in particular, the intake frequency of sucrose are of major
importance for the development of dental caries. The perception of sweet taste is
believed to have an influence on sucrose intake and therefore affects the
predisposition to dental caries. The aim was to study the caries experience and
sweet taste perception and to further analyze the possible relationship between
the 2 tested variables in 13- to 15-year-old children from 3 different
geographical areas. A cross-sectional survey comprising 669 children (220
Italian, 224 Mexican, and 225 Saudi Arabian) was conducted. The children were
examined in their school setting. A sweet taste perception level was determined
by the sweet taste threshold (TT) and sweet taste preference (TP). The sweet test
was performed with sucrose solutions varying in concentration from 1.63 to 821.52
g/L. The International Caries Detection and Assessment System (ICDAS) and DMFS
indices were used to diagnose caries. The highest mean value for TT was found for
Italian children followed by Saudi and Mexican. Saudi schoolchildren showed the
highest mean values for TP and DMFS, followed by Italian and Mexican. A
statistically significant difference for TP, TT, DMFS, and initial caries was
found between the 3 countries. A weak yet positive correlation was found between
taste perception (TT and TP) versus DMFS and manifest caries in all 3 countries
(r = 0.137-0.313). The findings of the present study showed a variation in sweet
taste perception between the 3 countries, which may influence the caries outcome
of the children in the individual countries
Performance Evaluation Of Biped Robot Optimal Gait Based On Genetic Algorithm
A Genetic Algorithm (GA) gait synthesis method for walking biped robots is considered in this paper. The walking occupy most of the time during the task performance, therefore its gait is analyzed based on the minimum consumed energy (CE) and minimum torque change (TC). The biped robot optimal gait is considered starting from static standing state and continuing with normal walking. The proposed method can be applied for wide ranges of step lengths and step times and for other tasks that might to be performed by humanoid robot. By using GA as an optimization tool it is easy to include constraints and add new variables to be optimized. The biped robot gait is generated without neglecting the stability, which is verified by the zero moment point ZMP concept. Simulations are realized based on the parameters of "Bonten-Maru I" humanoid robot. The evaluation by simulations shows that the proposed method has a good performance and energy is significantly reduced
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