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Lina Jaurigue, Eckehard Schöll, Kathy Lüdge
Many physical systems involve time-delayed feedback or coupling. In such delay systems, noise can give rise to undesirable oscillations at frequencies resonant to the delay times. We investigate how an additional feedback term can suppress noise-induced modulations in delay systems with self-feedback that exhibit deterministic oscillatory dynamics. A simple characteristic equation is derived to predict optimal delay times for the prototypical example of a Stuart-Landau oscillator subject to two feedback terms...
October 7, 2016: Physical Review Letters
Jacob Herrmann, Merryn H Tawhai, David W Kaczka
Regional ventilation in the injured lung is heterogeneous and frequency-dependent, making it difficult to predict how an oscillatory flow waveform at a specified frequency will be distributed throughout the periphery. To predict the impact of mechanical heterogeneity on regional ventilation distribution and gas transport, we developed a computational model of distributed gas flow and CO2 elimination during oscillatory ventilation from 0.1 to 30 Hz. The model consists of a three dimensional airway network of a canine lung, with heterogeneous parenchymal tissues to mimic effects of gravity and injury...
October 7, 2016: Journal of Applied Physiology
Elias Abou Zeid, Alborz Rezazadeh Sereshkeh, Tom Chau
OBJECTIVE: In recent years, the readiness potential (RP), a type of pre-movement neural activity, has been investigated for asynchronous electroencephalogram (EEG)-based brain-computer interfaces (BCIs). Since the RP is attenuated for involuntary movements, a BCI driven by RP alone could facilitate intentional control amid a plethora of unintentional movements. Previous studies have attempted single trial classification of RP via spatial and temporal filtering methods, or by combining the RP with event-related desynchronization...
October 20, 2016: Journal of Neural Engineering
Di Shu, Ionel Simbotin, Robin Côté
We investigate the energy dependence of inelastic processes in systemswhich possess Efimov states. We consider the three-body recombinationrate $K_3$ where three free atoms interact to produce anatom--dimer pair, and the relaxation rate $K_{\rm rel}$where an atom quenches a weakly bound state of a dimernear an Efimov resonance to more deeply bound levels.Using a modelcapturing the key features of the Efimov problem, weidentify new energy regimes for $K_3$, namely the NTR (NearThreshold Resonance) regime behavior $E^{-2}$ for negativescattering lengths and the NTS (Near Threshold Suppression) regimebehavior $E^2$ for positive scattering lengths...
October 19, 2016: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Soumyarwit Manna, James J Augsburger, Zelia M Correa, Marwan F Al-Rjoub, Marepalli B Rao, Rupak K Banerjee
PURPOSE: The purpose of this study is to noninvasively evaluate the safety and toxicity of a chitosan (CS) and polylactic acid (PLA)-based sustained-release methotrexate (MTX) intravitreal microimplant in normal rabbit eyes using electroretinography (ERG). METHODS: PLA-coated CS-based microimplants containing 400 μg of MTX and placebo microimplants (without drug) were surgically implanted in the vitreous of the right and the left eyes, respectively, in each of the 8 New Zealand rabbits using minimally invasive technique...
October 18, 2016: Journal of Ocular Pharmacology and Therapeutics
Rabea Seyboldt, Dimitri Merger, Fabian Coupette, Miriam Siebenbürger, Matthias Ballauff, Manfred Wilhelm, Matthias Fuchs
The leading nonlinear stress response in a periodically strained concentrated colloidal dispersion is studied experimentally and by theory. A thermosensitive microgel dispersion serves as well-characterized glass-forming model, where the stress response at the first higher harmonic frequency (3ω for strain at frequency ω) is investigated in the limit of small amplitude. The intrinsic nonlinearity at the third harmonic exhibits a scaling behavior which has a maximum in an intermediate frequency window and diverges when approaching the glass transition...
October 18, 2016: Soft Matter
A A Baker, A I Figueroa, D Pingstone, V K Lazarov, G van der Laan, T Hesjedal
We present a study of the interaction mechanisms in magnetic trilayer structures with an MgO barrier grown by molecular beam epitaxy. The interlayer exchange coupling, Aex, is determined using SQUID magnetometry and ferromagnetic resonance (FMR), displaying an unexpected oscillatory behaviour as the thickness, tMgO, is increased from 1 to 4 nm. Transmission electron microscopy confirms the continuity and quality of the tunnelling barrier, eliminating the prospect of exchange arising from direct contact between the two ferromagnetic layers...
October 18, 2016: Scientific Reports
Carles Soler, Jesús Contell, Lorena Bori, MarIa Sancho, Almudena García-Molina, Anthony Valverde, Jan Segarvall
This work provides information on the blue fox ejaculated sperm quality needed for seminal dose calculations. Twenty semen samples, obtained by masturbation, were analyzed for kinematic and morphometric parameters by using CASA-Mot and CASA-Morph system and principal component (PC) analysis. For motility, eight kinematic parameters were evaluated, which were reduced to PC1, related to linear variables, and PC2, related to oscillatory movement. The whole population was divided into three independent subpopulations: SP1, fast cells with linear movement; SP2, slow cells and nonoscillatory motility; and SP3, medium speed cells and oscillatory movement...
September 30, 2016: Asian Journal of Andrology
Antoine Wystrach, Konstantinos Lagogiannis, Barbara Webb
Taxis behaviour in Drosophila larva is thought to consist of distinct control mechanisms triggering specific actions. Here we support a simpler hypothesis: that taxis results from direct sensory modulation of continuous lateral oscillations of the anterior body, sparing the need for 'action selection'. Our analysis of larvae motion reveals a rhythmic, continuous lateral oscillation of the anterior body, encompassing all head-sweeps, small or large, without breaking the oscillatory rhythm. Further, we show that an agent-model that embeds this hypothesis reproduces a surprising number of taxis signatures observed in larvae...
October 18, 2016: ELife
Mao-Jun Li, Qing Wu, Wei Shi, Qian Yang, Bin-Zhi Tang, Chang-Hui Chen
OBJECTIVE: To study clinical features of respiratory distress syndrome (RDS) in neonates of different gestational ages (GA). METHODS: According to GA, 133 neonates with RDS were classified into GA <34 weeks group (n=66), GA 34-36 weeks group (late preterm neonates; n=31), and GA ≥37 weeks group (full-term neonates; n=36). The mothers' medical history during pregnancy and the condition of the neonates at birth were retrospectively analyzed, and the clinical data were compared between groups...
October 2016: Zhongguo Dang Dai Er Ke za Zhi, Chinese Journal of Contemporary Pediatrics
Folafoluwa O Odetola, Renee R Anspach, Yong Y Han, Sarah J Clark
PURPOSE: To investigate the decision making underlying transfer of children with respiratory failure from level II to level I pediatric intensive care unit care. METHODS: Interviews with 19 eligible level II pediatric intensive care unit physicians about a hypothetical scenario of a 2-year-old girl in respiratory failure: RESULTS: At baseline, indices critical to management were as follows: OI (53%), partial pressure of oxygen in arterial blood (Pao2)/Fio2 (32%), and inflation pressure (16%)...
October 4, 2016: Journal of Critical Care
Nicolas Fraize, Julien Carponcy, Mickaël Antoine Joseph, Jean-Christophe Comte, Pierre-Hervé Luppi, Paul-Antoine Libourel, Paul-Antoine Salin, Gaël Malleret, Régis Parmentier
STUDY OBJECTIVES: It is commonly accepted that sleep is beneficial to memory processes, but it is still unclear if this benefit originates from improved memory consolidation or enhanced information processing. It has thus been proposed that sleep may also promote forgetting of undesirable and non-essential memories, a process required for optimization of cognitive resources. We tested the hypothesis that non-rapid eye movement sleep (NREMS) promotes forgetting of irrelevant information, more specifically when processing information in working memory (WM), while REM sleep (REMS) facilitates the consolidation of important information...
October 10, 2016: Sleep
Alexander von Weber, Scott L Anderson
Mass-selected Ptn(+) ion deposition in ultrahigh vacuum (UHV) was used to prepare a series of size-selected electrodes with Ptn (n ≤ 14) clusters supported on either glassy carbon (GC) or indium tin oxide (ITO). After characterization of the physical properties of the electrodes in UHV, an in situ method was used to study electrocatalytic activity for the oxygen reduction and ethanol oxidation reactions, without significant air exposure. For each reaction studied, there are similarities between the catalytic properties of Ptn-containing electrodes and those of nanoparticulate or bulk Pt electrodes, but there are also important differences that provide mechanistic insights...
October 17, 2016: Accounts of Chemical Research
Jae W Chung, Edward Ofori, Gaurav Misra, Christopher W Hess, David E Vaillancourt
: Accurate motor performance may depend on the scaling of distinct oscillatory activity within the motor cortex and effective neural communication between the motor cortex and other brain areas. Oscillatory activity within the beta-band (13-30Hz) has been suggested to provide distinct functional roles for attention and sensorimotor control, yet it remains unclear how beta-band and other oscillatory activity within and between cortical regions is coordinated to enhance motor performance...
October 13, 2016: NeuroImage
Nicole David, Till R Schneider, Ina Peiker, Reem Al-Jawahiri, Andreas K Engel, Elizabeth Milne
Autism spectrum disorders (ASD) have been associated with altered neural oscillations, especially fast oscillatory activity in the gamma frequency range, suggesting fundamentally disturbed temporal coordination of activity during information processing. A detailed review of available cortical oscillation studies in ASD does not convey a clear-cut picture with respect to dysfunctional oscillation patterns in the gamma or other frequency ranges. Recent evidence suggests that instead of a general failure to activate or synchronize the cortex, there is greater intra-participant variability across behavioral, fMRI and EEG responses in ASD...
October 13, 2016: Neuroscience and Biobehavioral Reviews
Emanuela Zannin, Daniela Doni, Maria Luisa Ventura, Tiziana Fedeli, Camilla Rigotti, Raffaele L Dellacá, Paolo E Tagliabue
OBJECTIVE: To characterize changes in lung mechanics and right ventricular output (RVO) during incremental/decremental continuous distending pressure (CDP) maneuvers in newborn infants receiving high-frequency oscillatory ventilation, with the aim of evaluating when open lung maneuvers are needed and whether they are beneficial. STUDY DESIGN: Thirteen infants on high-frequency oscillatory ventilation were studied with a median (IQR) gestational age of 26(1) (25(3)-29(1)) weeks and median (IQR) body weight of 810 (600-1020) g...
October 10, 2016: Journal of Pediatrics
Tieh-Cheng Fu, Wen-Chen Lin, Jong-Shyan Wang, Chao-Hung Wang, Chun-Tien Chang, Cheng-Lun Tsai, Yun-Shien Lee, Kang-Ping Lin
Exercise periodic breathing (EPB) is associated with exercise intolerance and poor prognosis in patients with heart failure (HF). However, EPB detection during cardiopulmonary exercise test (CPET) is difficult. The present study investigated the use of a wireless monitoring device to record the EPB during CPET and proposed quantization parameter estimates for the EPB. A total of 445 patients with HF were enrolled and underwent exercise tests. The ventilation data from the wearable device were compared with the data obtained during the CPET and were analyzed based on professional opinion and on 2 automated programs (decision tree [DT] and oscillatory pattern methods)...
October 15, 2016: Medical & Biological Engineering & Computing
Randolph F Helfrich, Robert T Knight
The prefrontal cortex (PFC) provides the structural basis for numerous higher cognitive functions. However, it is still largely unknown which mechanisms provide the functional basis for flexible cognitive control of goal-directed behavior. Here, we review recent findings that suggest that the functional architecture of cognition is profoundly rhythmic and propose that the PFC serves as a conductor to orchestrate task-relevant large-scale networks. We highlight several studies that demonstrated that oscillatory dynamics, such as phase resetting, cross-frequency coupling (CFC), and entrainment, support PFC-dependent recruitment of task-relevant regions into coherent functional networks...
October 12, 2016: Trends in Cognitive Sciences
Fuyou Liang, Xiaosheng Liu, Ryuhei Yamaguchi, Hao Liu
Recent studies raised increasing concern about the reliability of computer models in reproducing in vivo hemodynamics in cerebral aneurysms. Boundary condition problem is among the most frequently addressed issues since three-dimensional (3-D) modeling is usually restricted to local arterial segments. The present study focused on aneurysms on the anterior communicating artery (ACoA) which represent a large subgroup of detected cerebral aneurysms and, in particular, have a relatively high risk of rupture compared to aneurysms located in other regions...
October 6, 2016: Journal of Biomechanics
Douglas McLelland, Rufin VanRullen
Several theories have been advanced to explain how cross-frequency coupling, the interaction of neuronal oscillations at different frequencies, could enable item multiplexing in neural systems. The communication-through-coherence theory proposes that phase-matching of gamma oscillations between areas enables selective processing of a single item at a time, and a later refinement of the theory includes a theta-frequency oscillation that provides a periodic reset of the system. Alternatively, the theta-gamma neural code theory proposes that a sequence of items is processed, one per gamma cycle, and that this sequence is repeated or updated across theta cycles...
October 2016: PLoS Computational Biology
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