Search results for "Modulation"
showing 10 items of 948 documents
Modulational instability and two-dimensional dynamical structures
2008
A process of nonlinear structure formation on a two-dimensional lattice is proposed. The basic model consists of a two-dimensional lattice equipped at each node with a molecule or dipole rotating in the lattice plane. The interactions involved in the model are reduced to a periodic lattice. Such a discrete system can be applied to the problem of molecule adsorption on a substrate crystal surface, for instance. The continuum approximation of the model leads to a 2-D sine-Gordon system including nonlinear couplings, which itself can be reduced to a 2-D nonlinear Schrodinger equation in the low amplitude limit. Spatio-temporal structure formation is investigated by means of numerical simulatio…
Immunotoxicity of Therapeutic Antibodies and Nanoparticles.
2020
Therapeutic antibodies and nanotherapeutic drugs are of great concern due to their widespread use against numerous diseases worldwide. They are frequently used for targeted therapy under the assumption that they cause fewer side effects than nontargeted drugs. Despite their specificity and particular design for therapeutic actions, they might still exhibit unintended adverse effects in the immune system. Immunotoxicity reactions are mediated by immunomodulation, including immunostimulation and immunosuppression. The present review gives an overview on the adverse immunotoxic effects induced by therapeutic antibodies as well as nanotherapeutic drugs. In this context, future methods combining…
Coalition: Advocacy for prospective clinical trials to test the post-exposure potential of hydroxychloroquine against COVID-19
2020
Our coalition of public health experts, doctors, and scientists worldwide want to draw attention to the need for high-quality evaluation protocols of the potential beneficial effect of hydroxychloroquine (HCQ) as a post-exposure drug for exposed people. In the absence of an approved, recognized effective pre or post-exposure prophylactic drug or vaccine for COVID-19, nor of any approved and validated therapeutic drug, coupled with social and political pressure raised by publicity both regarding the potential beneficial effect of hydroxychloroquine (HCQ) as well as potential risks from HCQ, we urge the immediate proper clinical trials. Specifically, we mean using HCQ for post-exposure of peo…
Comparative study of sensory modulation vulnerabilities in children with and without ASD in family and school contexts
2018
Background: Children with autism spectrum disorder (ASD) may present sensory processing alterations that are specific to each environment in which they develop, inevitably impacting their daily fun...
Early Brain Sensitivity to Word Frequency and Lexicality During Reading Aloud and Implicit Reading
2019
The present study investigated the influence of lexical word properties on the early stages of visual word processing (<250 ms) and how the dynamics of lexical access interact with task-driven top-down processes. We compared the brain's electrical response (event-related potentials, ERPs) of 39 proficient adult readers for the effects of word frequency and word lexicality during an explicit reading task versus a visual immediate-repetition detection task where no linguistic intention is required. In general, we observed that left-lateralized processes linked to perceptual expertise for reading are task independent. Moreover, there was no hint of a word frequency effect in early ERPs, while …
On the annual modulation signal in dark matter direct detection
2012
We derive constraints on the annual modulation signal in Dark Matter (DM) direct detection experiments in terms of the unmodulated event rate. A general bound independent of the details of DM distribution follows from the assumption that the motion of the earth around the sun is the only source of time variation. The bound is valid for a very general class of particle physics models and also holds in the presence of an unknown unmodulated background. More stringent bounds are obtained, if modest assumptions on symmetry properties of the DM halo are adopted. We illustrate the bounds by applying them to the annual modulation signals reported by the DAMA and CoGeNT experiments in the framework…
Generation of optical domain-wall structures from modulational instability in a bimodal fiber.
1998
We study experimentally modulational instability in a normally dispersive bimodal fiber under modal group-velocity-matching conditions. In the strong pump depletion regime, higher order sideband harmonics detected in the output spectra as well as autocorrelation measurements reveal the formation of subpicosecond domain-wall structures. Across these temporal structures the electromagnetic field distribution switches abruptly between the two transverse modes of the fiber. These structures are reminiscent of the so-called domain-wall soliton. Our results constitute therefore an experimental indication of the existence of this fundamental soliton.
New constraints on Lorentz invariance violation from the neutron electric dipole moment
2010
We propose an original test of Lorentz invariance in the interaction between a particle spin and an electromagnetic field and report on a first measurement using ultracold neutrons. We used a high sensitivity neutron electric dipole moment (nEDM) spectrometer and searched for a direction dependence of a nEDM signal leading to a modulation of its magnitude at periods of 12 and 24 hours. We constrain such a modulation to $d_{12} < 15 \times 10^{-25} \ e\,{\rm cm}$ and $d_{24} < 10 \times 10^{-25} \ e\,{\rm cm}$ at 95~\% C.L. The result translates into a limit on the energy scale for this type of Lorentz violation effect at the level of ${\cal E}_{LV} > 10^{10}$~GeV.
Experimental study on the influence of controller firmware on multirotor actuator dynamics
2014
In this paper the dynamic response of a propeller actuator commonly used in hobby unmanned aerial vehicles is studied experimentally. It is shown that the choice of electronic speed controller firmware has a significant effect on the overall actuator dynamics. Six different scenarios are tested: 1+2) Rising/falling step response with the standard firmware of the Hobbyking F30a, 3+4) Rising/falling step response with firmware from Simon Kirby/GitHub and 5+6) Rising/falling step response with firmware from Simon Kirby/GitHub including complementary Pulse-Width-Modulation (PWM) switching. Experimental results show a significant difference in actuator dynamics depending on the chosen firmware. …
The Antiviral Activity of Bacterial, Fungal, and Algal Polysaccharides as Bioactive Ingredients: Potential Uses for Enhancing Immune Systems and Prev…
2021
Viral infections may cause serious human diseases. For instance, the recent appearance of the novel virus, SARS-CoV-2, causing COVID-19, has spread globally and is a serious public health concern. The consumption of healthy, proper, functional, and nutrient-rich foods has an important role in enhancing an individual's immune system and preventing viral infections. Several polysaccharides from natural sources such as algae, bacteria, and fungi have been considered as generally recognized as safe (GRAS) by the US Food and Drug Administration. They are safe, low-toxicity, biodegradable, and have biological activities. In this review, the bioactive polysaccharides derived from various microorga…