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Signal detection theory

Aldo Eugenio Rossini, Fabrizio Gala, Mauro Chinappi, Giuseppe Zollo
Solid-state nanopores and nanogaps are emerging as promising tools for single molecule analysis. 2D materials, such as graphene, can potentially reach the spatial resolution needed for nucleic acid and protein sequencing. In the context of the density functional theory, atomistic modeling and non-equilibrium Green's function calculation, we show that glycine based polypeptide chains translocating across a nano-gap between two semi-infinite graphene nano-ribbons leave a specific transverse current signature for each peptide bond...
March 14, 2018: Nanoscale
Mahan Azadpour, Colette M McKay, Mario A Svirsky
Stimulation pulse rate affects current amplitude discrimination by cochlear implant (CI) users, indicated by the evidence that the JND (just noticeable difference) in current amplitude delivered by a CI electrode becomes larger at higher pulse rates. However, it is not clearly understood whether pulse rate would affect discrimination of speech intensities presented acoustically to CI processors, or what the size of this effect might be. Intensity discrimination depends on two factors: the growth of loudness with increasing sound intensity and the loudness JND (or the just noticeable loudness increment)...
March 12, 2018: Journal of the Association for Research in Otolaryngology: JARO
Dongmei Lin, Aihua Zhang, Jason Gu, Xiaolei Chen, Qi Wang, Liming Yang, Yongxin Chou, Gongcai Liu, Jingyang Wang
BACKGROUND AND OBJECTIVE: Pulse signals contain a wealth of human physiological and pathological information. How to get full pulse information is especially challenging, and most of the traditional pulse sensors can only get the pulse wave of a single point. This study is aimed at developing a binocular pulse detection system and method to obtain multipoint pulse waves and dynamic three-dimensional pulse shape of the radial artery. METHODS: The proposed pulse detection approach is image-based and implemented by two steps...
March 2018: Computer Methods and Programs in Biomedicine
Jing Wu, Yunlei Xianyu, Xiangfeng Wang, Dehua Hu, Zhitao Zhao, Ning Lu, Meng-Xia Xie, Hongtao Lei, Yiping Chen
In this work, we outline a signal amplification strategy using the coordination chemistry between Fe3+ and polyglutamic acid (PGA) for biosensing applications. The theoretical calculation based on density functional theory shows that PGA has a much higher binding affinity with Fe3+ than the other metal ions. Guided by this rationale, we prepare a PGA-mediated signal probe through conjugating PGA onto polystyrene (PS) nanoparticles to form a brush-like nanostructure for Fe3+ coordination. This PGA-PS brush (PPB) has a large loading capacity of Fe3+ with a number of 1...
March 7, 2018: Analytical Chemistry
Thomas Zhihao Luo, John H R Maunsell
Visual attention is associated with neuronal changes across the brain, and these widespread signals are generally assumed to underlie a unitary mechanism of attention. However, using signal detection theory, attention-related effects on performance can be partitioned into changes in either the subject's criterion or sensitivity. Neuronal modulations associated with only sensitivity changes were previously observed in visual cortex, raising questions about which structures mediate attention-related changes in criterion and whether individual neurons are involved in multiple components of attention...
February 23, 2018: Neuron
Xiaorong Zhang, Bincheng Li
An accurate theoretical model based on thermoelasticity theory and Fresnel diffraction integral is developed to describe the photothermal deflection (PTD) signal with a continuous-wave modulated Gaussian beam excitation. A PTD experiment is performed to investigate the dependence of PTD amplitude on the experimental parameters, such as the radius, waist position, and wavelength of the probe beam, and the detection distance. Good agreement between the experimental and theoretical results is obtained. The results reveal that the optimal detection distance highly depends on the probe beam waist position and wavelength, and the PTD amplitude can be enhanced by optimizing the probe beam radius and waist position as well as the detection distance...
February 2018: Review of Scientific Instruments
Claire White, Daniel M T Fessler
Grief is characterized by a number of cardinal cognitive symptoms, including preoccupation with thoughts of the deceased and vigilance toward indications that the deceased is in the environment. Compared with emotional symptoms, little attention has been paid to the ultimate function of vigilance in grief. Drawing on signal-detection theory, we propose that the ultimate function of vigilance is to facilitate the reunification (where possible) with a viable relationship partner following separation. Preoccupation with thoughts about the missing person creates the cognitive conditions necessary to maintain a low baseline threshold for the detection of the agent-any information associated with the agent is highly salient, and attention is correspondingly readily deployed toward such cues...
2018: Evolution, Medicine, and Public Health
Geoff Davies, Charlotte L Rae, Sarah N Garfinkel, Anil K Seth, Nick Medford, Hugo D Critchley, Kathryn Greenwood
INTRODUCTION: Metacognition, or "thinking about thinking", is a higher-order thought process that allows for the evaluation of perceptual processes for accuracy. Metacognitive accuracy is associated with the grey matter volume (GMV) in the prefrontal cortex (PFC), an area also impacted in schizophrenia. The present study set out to investigate whether deficits in metacognitive accuracy are present in the early stages of psychosis. METHODS: Metacognitive accuracy in first-episode psychosis (FEP) was assessed on a perceptual decision-making task and their performance compared to matched healthy control participants (N = 18)...
February 27, 2018: Cognitive Neuropsychiatry
Benjamin Djulbegovic, Iztok Hozo, William Dale
BACKGROUND: Contemporary delivery of health care is inappropriate in many ways, largely due to suboptimal Q5 decision-making. A typical approach to improve practitioners' decision-making is to develop evidence-based clinical practice guidelines (CPG) by guidelines panels, who are instructed to use their judgments to derive practice recommendations. However, mechanisms for the formulation of guideline judgments remains a "black-box" operation-a process with defined inputs and outputs but without sufficient knowledge of its internal workings...
February 27, 2018: Journal of Evaluation in Clinical Practice
Shi-Fan Xue, Jing-Fei Zhang, Zi-Han Chen, Xin-Yue Han, Min Zhang, Guoyue Shi
A novel type of stimuli-responsive fluorescent polymers has been developed via the self-assembly of riboflavin-5'-phosphate (RiP) as ligand and europium (III) (Eu3+ ) as central metal ion coordinated with the ligand. The as-prepared RiP/Eu3+ coordination polymers (RiP/Eu3+ CPs) are smart and multifunctional for respectively responding to chemical and physical stimuli, in which RiP acts as the stimuli-responsive fluorescent signal indicator. For sensing chemical stimuli, 2,6-pyridinedicarboxylic acid (DPA, an anthrax biomarker) having higher bonding force towards Eu3+ can grab it from smart RiP/Eu3+ CPs through competition reaction, resulting in the release of RiP for highly sensitive and selective DPA monitoring in a mix-and-read fluorescent enhancement format, and the detection limit is as low as 41...
July 5, 2018: Analytica Chimica Acta
Rimona S Weil, Dietrich S Schwarzkopf, Bahador Bahrami, Stephen M Fleming, Ben M Jackson, Tristam J C Goch, Ayse P Saygin, Luke E Miller, Katerina Pappa, Ivanna Pavisic, Rachel N Schade, Alastair J Noyce, Sebastian J Crutch, Aidan G O'Keeffe, Anette E Schrag, Huw R Morris
BACKGROUND: People with Parkinson's disease (PD) who develop visuo-perceptual deficits are at higher risk of dementia, but we lack tests that detect subtle visuo-perceptual deficits and can be performed by untrained personnel. Hallucinations are associated with cognitive impairment and typically involve perception of complex objects. Changes in object perception may therefore be a sensitive marker of visuo-perceptual deficits in PD. OBJECTIVE: We developed an online platform to test visuo-perceptual function...
February 23, 2018: Movement Disorders: Official Journal of the Movement Disorder Society
Myron Tsikandilakis, Peter Chapman
The biological preparedness model suggests that survival-related visual cues elicit physiological changes without awareness to enable us to respond to our environment. Previous studies have reported some evidence for this effect. In the current article, we argue that this evidence is subject to methodological confounds. These include the use of a universal masked presentation threshold, the employment of hit rates (HRs) to measure meta-awareness, and the assertion of overall guess-level target detection using nonsignificance...
January 1, 2018: Perception
Justin Faber, Dolores Bozovic
Experimental records of active bundle motility are used to demonstrate the presence of a low-dimensional chaotic attractor in hair cell dynamics. Dimensionality tests from dynamic systems theory are applied to estimate the number of independent variables sufficient for modelling the hair cell response. Poincaré maps are constructed to observe a quasiperiodic transition from chaos to order with increasing amplitudes of mechanical forcing. The onset of this transition is accompanied by a reduction of Kolmogorov entropy in the system and an increase in transfer entropy between the stimulus and the hair bundle, indicative of signal detection...
February 20, 2018: Scientific Reports
Cailey Bromer, Thomas M Bartol, Jared B Bowden, Dusten D Hubbard, Dakota C Hanka, Paola V Gonzalez, Masaaki Kuwajima, John M Mendenhall, Patrick H Parker, Wickliffe C Abraham, Terrence J Sejnowski, Kristen M Harris
An approach combining signal detection theory and precise 3D reconstructions from serial section electron microscopy (3DEM) was used to investigate synaptic plasticity and information storage capacity at medial perforant path synapses in adult hippocampal dentate gyrus in vivo. Induction of long-term potentiation (LTP) markedly increased the frequencies of both small and large spines measured 30 minutes later. This bidirectional expansion resulted in heterosynaptic counterbalancing of total synaptic area per unit length of granule cell dendrite...
February 20, 2018: Proceedings of the National Academy of Sciences of the United States of America
Subhojyoti Chatterjee, Seth Olsen, Ewan W Blanch, Feng Wang
Resveratrol (RSVL) is a stilbenoid phytoalexin with promised myriad health benefits predominantly attributed to the trans (E) diastereomeric form. A recent study has implicated the Z (cis) diastereomer in human health. This stereoisomer binds with high affinity to human tyrosyl-tRNA synthetase, initiating a downstream cascade that promotes the expression of genes associated with the cellular stress response. We discovered that the non-planar structure of cis-resveratrol conformer possesses certain chiral signals in its simulated vibrational circular dichroism (VCD) and Raman optical activity (ROA) spectra...
February 17, 2018: Journal of Physical Chemistry. B
Milan Boublík, Martina Riesová, Pavel Dubský, Bohuslav Gaš
Conductivity detection is a universal detection technique often encountered in electrophoretic separation systems, especially in modern chip-electrophoresis based devices. On the other hand, it is sparsely combined with another contemporary trend of enhancing limits of detection by means of various preconcentration strategies. This can be attributed to the fact that a preconcentration experimental setup usually brings about disturbances in a conductivity baseline. Sweeping with a neutral sweeping agent seems a good candidate for overcoming this problem...
February 16, 2018: Electrophoresis
Lukas Bruder, Marcel Binz, Frank Stienkemeier
We introduce the concept of phase-synchronous undersampling in nonlinear spectroscopy. The respective theory is presented and validated experimentally in a phase-modulated quantum beat experiment by sampling high phase modulation frequencies with low laser repetition rates. The advantage of undersampling in terms of signal quality and reduced acquisition time is demonstrated, and breakdown conditions are identified. The presented method is particularly beneficial for experimental setups with limited signal/detection rates...
February 15, 2018: Optics Letters
Yang Ni
In this paper, we present a new logarithmic pixel design currently under development at New Imaging Technologies SA (NIT). This new logarithmic pixel design uses charge domain logarithmic signal compression and charge-transfer-based signal readout. This structure gives a linear response in low light conditions and logarithmic response in high light conditions. The charge transfer readout efficiently suppresses the reset (KTC) noise by using true correlated double sampling (CDS) in low light conditions. In high light conditions, thanks to charge domain logarithmic compression, it has been demonstrated that 3000 electrons should be enough to cover a 120 dB dynamic range with a mobile phone camera-like signal-to-noise ratio (SNR) over the whole dynamic range...
February 14, 2018: Sensors
Raven Garvey
Archaeology has much to contribute to the study of cultural evolution. Empirical data at archaeological timescales are uniquely well suited to tracking rates of cultural change, detecting phylogenetic signals among groups of artefacts, and recognizing long-run effects of distinct cultural transmission mechanisms. Nonetheless, these are still relatively infrequent subjects of archaeological analysis and archaeology's potential to help advance our understanding of cultural evolution has thus far been largely unrealized...
April 5, 2018: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Robert B Channon, Michael P Nguyen, Alexis G Scorzelli, Elijah M Henry, John Volckens, David S Dandy, Charles S Henry
Microfluidic paper-based analytical devices (μPADs) are a versatile and inexpensive point-of-care (POC) technology, but their widespread adoption has been limited by slow flow rates and the inability to carry out complex in field analytical measurements. In the present work, we investigate multilayer μPADs as a means to generate enhanced flow rates within self-pumping paper devices. Through optical and electrochemical measurements, the fluid dynamics are investigated and compared to established flow theories within μPADs...
February 12, 2018: Lab on a Chip
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