Search results for "Rhythm"
showing 10 items of 822 documents
Effects of low-gamma tACS on primary motor cortex in implicit motor learning
2019
Abstract In the primary motor cortex (M1), rhythmic activity in the gamma frequency band has been found during movement planning, onset and execution. Although the role of high-gamma oscillatory activity in M1 is well established, the contribution of low-gamma activity is still unexplored. In this study, transcranial alternating current stimulation (tACS) was used with the aim to specifically modulate low-gamma frequency band in M1, during an implicit motor learning task. A 40 Hz-tACS was applied over the left M1 while participants performed a serial reaction time task (SRTT) using their right hand. The task required the repetitive execution of sequential movements in response to sequences …
Diel feeding habits of juveniles of Mullus surmuletus (Linneo, 1758) in the lagoon of the Stagnone di Marsala (Western Sicily, Italy)
1999
Diet composition, feeding rhythm, gastric evacuation rate and daily ration were investigated in juvenile Mulhis surmuletus (Linneo, 1758). Fish were collected in the lagoon of the Stagnone di Marsala in western Sicily, in July 1995, during a 24 h sampling period. Copepoda, Polychaeta, Amphipoda and Tanaidacea were shown to be the most frequent prey items. The feeding index values showed two different daily feeding times. A unimodal trend in the daily rhythm of food consumption was derived, with a peak in feeding between 1200 and 2000 h. Gastric evacuation in juvenile M. surmuletus is best described by an exponential model, with a gastric evacuation rate R = 0.66 g h-1 (r = 0.88) (T = 24.45 …
TickTacking – Drawing trajectories with two buttons and rhythm
2023
The navigation of two-dimensional spaces by rhythmic patterns on two buttons is investigated. It is shown how direction and speed of a moving object can be controlled with discrete commands consisting of duplets or triplets of taps, whose rate is proportional to one of two orthogonal velocity components. The imparted commands generate polyrhythms and polytempi that can be used to monitor the object movement. Tacking back and forth must be used to make progress along certain directions, similarly to sailing a boat upwind. The proposed rhythmic navigation technique is tested with a target-following task, using a boat-racing trace as the target. The interface is minimal and symmetric, and can …
Per il testo, il ritmo e lo iato dell´Epistola di Aristea a Filocrate
2021
Epistulae Aristeae ad Philocratem loci nonnulli ad genuinam lectionem revocantur; praeterea quaeritur utrum hiatus vitetur atque clausolae numerosae sint. The aim of the first part of this paper is to cast new light on the textual constitution of some passages of the Epistula Aristeae ad Philocratem. Ca. 20 pieces are discussed and for most of them a new solution is proposed; in the other cases I argue for a solution already proposed, but not accepted by the editors. The aim of the second part is to establish whether the ps.-Aristeas used rhythmical prose or not, and whether he avoided the hiatus. The analysis shows that he wrote rhythmical prose and avoided the hiatus.
The effect of time-of-day and sleep deprivation on postural control: A systematic review.
2022
Background: Postural control (PC) can be affected by circadian rhythm and sleep deprivation, whereby it has been reported the result of PC measurement in clinical and experimental situations can be influenced by both factors. It has been suggested sleepiness can result in deficiency in PC, which in turn can lead to occupational accidents and subsequent injuries. This is while no study critically reviews or summarizes findings surrounding this topic in the literature. Research question: Is there any significant effect of sleep deprivation and circadian rhythm on PC variables among healthy individuals? Methods: PubMed, Web of Science, Scopus, and Embase were used to detect relevant studies. O…
Circadian rhythms and nutrition
2014
The system of Circadian Rhythms is a mechanism that, in the forms of animal life, has evolved in order to synchronize the behavior and physiological responses to environmental periodical stimuli, so as to allow faster response and better adaptation to environmental changes. These stimuli (light, food availability, presence of predators, availability of a partner for reproduction) in turn depend on the rotation of the earth on its axis and around the sun. In mammals, there is a central hypothalamic clock , said Master Clock, directly regulated by light in its periodicity, which therefore plays the role of primary synchronizer, and several peripheral clocks, Slave Clock, synchronized with eac…
Sickness Absence at Work and Supporting Being Present At Work, Among Employees Working Different Shifts in the Forest Industry
2015
Objective: Shift work has negative effects on employee overall health, including sleep disorder, depressive symptoms, and cardiovascular and metabolic diseases. The association between shift work and the prevalence of sickness absence has been less studied. This study investigated sickness absence among employees working different work shift schedules in the forest industry. Method: This descriptive cross-sectional study used employee (N=636) data from forest industry sick-leave registers. The study population (n=280; women n=90 and men=189) worked five different shifts. Each of the five shifts was analyzed separately for sickness absence rate and the results were compared using independent…
A method for quantifying atrial fibrillation organization based on wave-morphology similarity
2002
A new method for quantifying the organization of single bipolar electrograms recorded in the human atria during atrial fibrillation (AF) is presented. The algorithm relies on the comparison between pairs of local activation waves (LAWs) to estimate their morphological similarity, and returns a regularity index (/spl rho/) which measures the extent of repetitiveness over time of the detected activations. The database consisted of endocardial data from a multipolar basket catheter during AF and intraatrial recordings during atrial flutter. The index showed maximum regularity (/spl rho/=1) for all atrial flutter episodes and decreased significantly when increasing AF complexity as defined by W…
An Automatic System for the Analysis and Classification of Human Atrial Fibrillation Patterns from Intracardiac Electrograms
2008
This paper presents an automatic system for the analysis and classification of atrial fibrillation (AF) patterns from bipolar intracardiac signals. The system is made up of: 1) a feature- extraction module that defines and extracts a set of measures potentially useful for characterizing AF types on the basis of their degree of organization; 2) a feature-selection module (based on the Jeffries-Matusita distance and a branch and bound search algorithm) identifying the best subset of features for discriminating different AF types; and 3) a support vector machine technique-based classification module that automatically discriminates the AF types according to the Wells' criteria. The automatic s…
Complexity analysis of experimental cardiac arrhythmia
2014
International audience; To study the cardiac arrhythmia, an in vitro experimental model and Multielectrodes Array (MEA) are used. This platform serves as an intermediary of the electrical activities of cardiac cells and the signal processing / dynamics analysis. Through it the extracellular potential of cardiac cells is acquired, allowing a real-time monitoring / analyzing. Since MEA has 60 electrodes / channels dispatched in a rectangular region, it allows real-time monitoring and signal acquisition on multiple sites. The in vitro experimental model (cardiomyocytes cultures from new-born rats' heart) is directly prepared on the MEA. This carefully prepared culture has similar parameters as…