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https://www.readbyqxmd.com/read/28813566/a-nonlinear-generalization-of-the-savitzky-golay-filter-and-the-quantitative-analysis-of-saccades
#1
Weiwei Dai, Ivan Selesnick, John-Ross Rizzo, Janet Rucker, Todd Hudson
The Savitzky-Golay (SG) filter is widely used to smooth and differentiate time series, especially biomedical data. However, time series that exhibit abrupt departures from their typical trends, such as sharp waves or steps, which are of physiological interest, tend to be oversmoothed by the SG filter. Hence, the SG filter tends to systematically underestimate physiological parameters in certain situations. This article proposes a generalization of the SG filter to more accurately track abrupt deviations in time series, leading to more accurate parameter estimates (e...
August 1, 2017: Journal of Vision
https://www.readbyqxmd.com/read/28812067/nonlinear-imaging-microscopy-for-assessing-structural-and-photochemical-modifications-upon-laser-removal-of-dammar-varnish-on-photosensitive-substrates
#2
M Oujja, S Psilodimitrakopoulos, E Carrasco, M Sanz, A Philippidis, A Selimis, P Pouli, G Filippidis, M Castillejo
The nonlinear optical microscopy (NLM) modalities of Multi-Photon Excited Fluorescence (MPEF) and Third Harmonic Generation (THG) have been combined in this work to characterize as a function of depth with micrometric resolution the type and extent of morphological and photochemical modifications that take place upon ultraviolet (UV) pulsed laser removal of a dammar varnish layer applied on a photosensitive substrate. The latter consists on a layer of the synthetic polymer poly-methyl methacrylate doped with a photosensitizer, the aromatic compound 1,4-di[2-(5-phenyloxazolyl)] benzene, that strongly fluoresces upon UV light illumination...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28808305/multipolar-second-harmonic-generation-in-a-symmetric-nonlinear-metamaterial
#3
Omri Wolf, Salvatore Campione, Yuanmu Yang, Igal Brener
Optical nonlinearities are intimately related to the spatial symmetry of the nonlinear media. For example, the second order susceptibility vanishes for centrosymmetric materials under the dipole approximation. The latter concept has been naturally extended to the metamaterials' realm, sometimes leading to the (erroneous) hypothesis that second harmonic (SH) generation is negligible in highly symmetric meta-atoms. In this work we aim to show that such symmetric meta-atoms can radiate SH light efficiently. In particular, we investigate in-plane centrosymmetric meta-atom designs where the approximation for meta-atoms breaks down...
August 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28768317/hue-shifts-produced-by-temporal-asymmetries-in-chromatic-signals
#4
Andrew Stockman, G Bruce Henning, Peter West, Andrew T Rider, Hannah E Smithson, Caterina Ripamonti
Observers viewed M- or L-cone-isolating stimuli and compared slowly-on and slowly-off sawtooth waveforms of the same mean chromaticity and luminance. Between 6 and 13 Hz, the mean hue of slowly-on L-cone and slowly-off M-cone sawtooth flicker appeared redder, and the mean hue of slowly-off L-cone and slowly-on M-cone sawtooth stimuli appeared greener-despite all the waveforms' having the same mean, near-yellow-appearing chromaticity. We measured the effect of the modulation depth and the slope of the sawtooth on the mean hue shifts as a function of temporal frequency...
August 1, 2017: Journal of Vision
https://www.readbyqxmd.com/read/28753430/defining-a-cancer-dependency-map
#5
Aviad Tsherniak, Francisca Vazquez, Phil G Montgomery, Barbara A Weir, Gregory Kryukov, Glenn S Cowley, Stanley Gill, William F Harrington, Sasha Pantel, John M Krill-Burger, Robin M Meyers, Levi Ali, Amy Goodale, Yenarae Lee, Guozhi Jiang, Jessica Hsiao, William F J Gerath, Sara Howell, Erin Merkel, Mahmoud Ghandi, Levi A Garraway, David E Root, Todd R Golub, Jesse S Boehm, William C Hahn
Most human epithelial tumors harbor numerous alterations, making it difficult to predict which genes are required for tumor survival. To systematically identify cancer dependencies, we analyzed 501 genome-scale loss-of-function screens performed in diverse human cancer cell lines. We developed DEMETER, an analytical framework that segregates on- from off-target effects of RNAi. 769 genes were differentially required in subsets of these cell lines at a threshold of six SDs from the mean. We found predictive models for 426 dependencies (55%) by nonlinear regression modeling considering 66,646 molecular features...
July 27, 2017: Cell
https://www.readbyqxmd.com/read/28748486/nonlinear-processing-of-a-multicomponent-communication-signal-by-combination-sensitive-neurons-in-the-anuran-inferior-colliculus
#6
Norman Lee, Katrina M Schrode, Mark A Bee
Diverse animals communicate using multicomponent signals. How a receiver's central nervous system integrates multiple signal components remains largely unknown. We investigated how female green treefrogs (Hyla cinerea) integrate the multiple spectral components present in male advertisement calls. Typical calls have a bimodal spectrum consisting of formant-like low-frequency (~0.9 kHz) and high-frequency (~2.7 kHz) components that are transduced by different sensory organs in the inner ear. In behavioral experiments, only bimodal calls reliably elicited phonotaxis in no-choice tests, and they were selectively chosen over unimodal calls in two-alternative choice tests...
July 26, 2017: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
https://www.readbyqxmd.com/read/28734190/two-dimensional-modeling-of-elastic-wave-propagation-in-solids-containing-cracks-with-rough-surfaces-and-friction-part-ii-numerical-implementation
#7
Steven Delrue, Vladislav Aleshin, Kevin Truyaert, Olivier Bou Matar, Koen Van Den Abeele
Our study aims at the creation of a numerical toolbox that describes wave propagation in samples containing internal contacts (e.g. cracks, delaminations, debondings, imperfect intergranular joints) of known geometry with postulated contact interaction laws including friction. The code consists of two entities: the contact model and the solid mechanics module. Part I of the paper concerns an in-depth description of a constitutive model for realistic contacts or cracks that takes into account the roughness of the contact faces and the associated effects of friction and hysteresis...
July 13, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28734189/two-dimensional-modeling-of-elastic-wave-propagation-in-solids-containing-cracks-with-rough-surfaces-and-friction-part-i-theoretical-background
#8
Vladislav Aleshin, Steven Delrue, Andrey Trifonov, Olivier Bou Matar, Koen Van Den Abeele
Our study aims at the creation of a numerical toolbox that describes wave propagation in samples containing internal contacts (e.g. cracks, delaminations, debondings, imperfect intergranular joints) of known geometry with postulated contact interaction laws including friction. The code consists of two entities: the contact model and the solid mechanics module. Part I of the paper concerns the modeling of internal contacts (called cracks for brevity), while part II is related to the integration of the developed contact model into a solid mechanics module that allows the description of wave propagation processes...
July 13, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28718769/pesticide-exposure-and-risk-of-rheumatoid-arthritis-among-licensed-male-pesticide-applicators-in-the-agricultural-health-study
#9
Armando Meyer, Dale P Sandler, Laura E Beane Freeman, Jonathan N Hofmann, Christine G Parks
BACKGROUND: The occupation of farming has been associated with rheumatoid arthritis (RA); pesticides may account for this association, but there are few studies. OBJECTIVES: We investigated associations between RA and use of pesticides in the Agricultural Health Study. METHODS: The study sample was drawn from male pesticide applicators enrolled in 1993-1997 who provided questionnaire data at baseline and at least once during follow-up (over a median 18 y; interquartile range 16-19)...
July 14, 2017: Environmental Health Perspectives
https://www.readbyqxmd.com/read/28709329/empirical-resistive-force-theory-for-slender-biological-filaments-in-shear-thinning-fluids
#10
Emily E Riley, Eric Lauga
Many cells exploit the bending or rotation of flagellar filaments in order to self-propel in viscous fluids. While appropriate theoretical modeling is available to capture flagella locomotion in simple, Newtonian fluids, formidable computations are required to address theoretically their locomotion in complex, nonlinear fluids, e.g., mucus. Based on experimental measurements for the motion of rigid rods in non-Newtonian fluids and on the classical Carreau fluid model, we propose empirical extensions of the classical Newtonian resistive-force theory to model the waving of slender filaments in non-Newtonian fluids...
June 2017: Physical Review. E
https://www.readbyqxmd.com/read/28709324/geometric-structure-and-information-change-in-phase-transitions
#11
Eun-Jin Kim, Rainer Hollerbach
We propose a toy model for a cyclic order-disorder transition and introduce a geometric methodology to understand stochastic processes involved in transitions. Specifically, our model consists of a pair of forward and backward processes (FPs and BPs) for the emergence and disappearance of a structure in a stochastic environment. We calculate time-dependent probability density functions (PDFs) and the information length L, which is the total number of different states that a system undergoes during the transition...
June 2017: Physical Review. E
https://www.readbyqxmd.com/read/28701692/next-generation-driver-for-attosecond-and-laser-plasma-physics
#12
D E Rivas, A Borot, D E Cardenas, G Marcus, X Gu, D Herrmann, J Xu, J Tan, D Kormin, G Ma, W Dallari, G D Tsakiris, I B Földes, S-W Chou, M Weidman, B Bergues, T Wittmann, H Schröder, P Tzallas, D Charalambidis, O Razskazovskaya, V Pervak, F Krausz, L Veisz
The observation and manipulation of electron dynamics in matter call for attosecond light pulses, routinely available from high-order harmonic generation driven by few-femtosecond lasers. However, the energy limitation of these lasers supports only weak sources and correspondingly linear attosecond studies. Here we report on an optical parametric synthesizer designed for nonlinear attosecond optics and relativistic laser-plasma physics. This synthesizer uniquely combines ultra-relativistic focused intensities of about 10(20) W/cm(2) with a pulse duration of sub-two carrier-wave cycles...
July 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28676748/regularity-of-center-of-pressure-trajectories-in-expert-gymnasts-during-bipedal-closed-eyes-quiet-standing
#13
Brice Isableu, Petra Hlavackova, Bruno Diot, Nicolas Vuillerme
We compared postural control of expert gymnasts (G) to that of non-gymnasts (NG) during bipedal closed-eyes quiet standing using conventional and nonlinear dynamical measures of center of foot pressure (COP) trajectories. Earlier findings based on COP classical variables showed that gymnasts exhibited a better control of postural balance but only in demanding stances. We examined whether the effect of expertise in Gymnastic can be uncovered in less demanding stances, from the analysis of the dynamic patterns of COP trajectories...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28674870/heart-rate-response-to-alpha2-adrenergic-receptor-antagonism-by-antipsychotics
#14
David D Kim, Donna J Lang, Darren E R Warburton, Melissa L Woodward, Randall F White, Alasdair M Barr, William G Honer, Ric M Procyshyn
PURPOSE: To explore the relationship between antipsychotic-associated antagonism of alpha2-adrenergic receptors and resting heart rate in individuals with schizophrenia. METHODS: Thirty-one inpatients treated with antipsychotics were included in this exploratory analysis. Antipsychotic doses were converted to haloperidol equivalents for alpha2-adrenergic receptor antagonism. Resting heart rate was measured with the patient in the seated upright posture. RESULTS: After controlling for confounding variables, the relationship between alpha2-adrenergic receptor antagonism and resting heart rate demonstrated a positive linear effect (P = 0...
July 3, 2017: Clinical Autonomic Research: Official Journal of the Clinical Autonomic Research Society
https://www.readbyqxmd.com/read/28668593/mechanical-characterization-and-finite-element-implementation-of-the-soft-materials-used-in-a-novel-anthropometric-test-device-for-simulating-underbody-blast-loading
#15
Wade A Baker, Costin D Untaroiu, Dawn M Crawford, Mostafiz R Chowdhury
Soft materials (e.g. polymers) are widely used in biomechanical devices to represent the nonlinear viscoelastic properties inherent in biological soft tissues. Knowledge of their mechanical properties is used to inform design choices and develop accurate finite element (FE) models of human surrogates. The goal of this study was to characterize the behavior of eight polymeric materials used in the design of a novel anthropomorphic test device (ATD) and implement these materials in an FE model of the ATD. Tensile and compressive tests at strain rates ranging from 0...
June 23, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28665320/dimension-reduced-analog-digital-mixed-measurement-method-of-inductive-proximity-sensor
#16
Yi-Xin Guo, Zhi-Biao Shao, Hui-Bin Tao, Kai-Liang Xu, Ting Li
Inductive proximity sensors (IPSs) present a unique no-contact advantage. They are widely preferred for displacement measurement in various industrial fields (e.g., aviation and aerospace), and they are improved continuously. When the inductance and resistance components of the IPS sensing core are separated, the influence of temperature drift on measurement can be eliminated. The complexity of online computation of component separation can be reduced using a two-dimensional look-up table method. However, this method exhibits disadvantages, such as large capacity of the look-up table, dependency on precision measurement of sensing core parameter, and nonlinear distribution of measurement resolution...
June 30, 2017: Sensors
https://www.readbyqxmd.com/read/28659592/ultra-broadband-enhancement-of-nonlinear-optical-processes-from-randomly-patterned-super-absorbing-metasurfaces
#17
Nan Zhang, Ziheng Ji, Alec R Cheney, Haomin Song, Dengxin Ji, Xie Zeng, Borui Chen, Tianmu Zhang, Alexander N Cartwright, Kebin Shi, Qiaoqiang Gan
Broadband light trapping and field localization is highly desired in enhanced light-matter interaction, especially in harmonic generations. However, due to the limited resonant bandwidth, most periodic plasmonic nanostructures cannot cover both fundamental excitation wavelength and harmonic generation wavelength simultaneously. Therefore, most previously reported plasmonic nonlinear optical processes are low in conversion efficiency. Here, we report a strong enhancement of second harmonic generation based on a three-layered super absorbing metasurface structure consisting of a dielectric spacer layer sandwiched by an array of random metallic nanoantennas and a metal ground plate...
June 28, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28658600/rheological-characterization-of-human-brain-tissue
#18
S Budday, G Sommer, J Haybaeck, P Steinmann, G A Holzapfel, E Kuhl
The rheology of ultrasoft materials like the human brain is highly sensitive to regional and temporal variations and to the type of loading. While recent experiments have shaped our understanding of the time-independent, hyperelastic response of human brain tissue, its time-dependent behavior under various loading conditions remains insufficiently understood. Here we combine cyclic and relaxation testing under multiple loading conditions, shear, compression, and tension, to understand the rheology of four different regions of the human brain, the cortex, the basal ganglia, the corona radiata, and the corpus callosum...
June 26, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28653335/catlas-an-magnetic-resonance-imaging-based-three-dimensional-cortical-atlas-and-tissue-probability-maps-for-the-domestic-cat-felis-catus
#19
Daniel Stolzberg, Carmen Wong, Blake E Butler, Stephen G Lomber
Brain atlases play an important role in effectively communicating results from neuroimaging studies in a standardized coordinate system. Furthermore, brain atlases extend analysis of functional magnetic resonance imaging (MRI) data by delineating regions of interest over which to evaluate the extent of functional activation as well as measures of inter-regional connectivity. Here, we introduce a three-dimensional atlas of the cat cerebral cortex based on established cytoarchitectonic and electrophysiological findings...
June 27, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28653244/%C3%AE-hydroxybutyric-acid-ghb-pharmacokinetics-and-pharmacodynamics-semi-mechanistic-and-physiologically-relevant-pk-pd-model
#20
Rutwij A Dave, Kristin E Follman, Marilyn E Morris
An overdose of γ-hydroxybutyric acid (GHB), a drug of abuse, results in fatality caused by severe respiratory depression. In this study, a semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model was developed to characterize monocarboxylate transporter 1 (MCT1)-mediated transport of GHB, as well as effects of GHB on respiration frequency, for IV doses of 200, 600, and 1500 mg/kg in rats. The proposed PK/PD model for GHB consists of nonlinear metabolism of GHB in the liver, MCT1-mediated renal reabsorption with physiologically relevant concurrent fluid reabsorption, MCT1-mediated uptake into the brain, and direct effects of binding of GHB to GABAB receptors on the PD parameter, respiration frequency...
June 26, 2017: AAPS Journal
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