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Signal detection theory

Nuttida Rungratsameetaweemana, Sirawaj Itthipuripat, Annalisa Salazar, John T Serences
Two factors play an important role in shaping perception: the allocation of selective attention to behaviorally relevant sensory features, and prior expectations about regularities in the environment. Signal detection theory proposes distinct roles of attention and expectation on decision-making such that attention modulates early sensory processing whereas expectation influences the selection and execution of motor responses. Challenging this classic framework, recent studies suggest that expectations about sensory regularities enhance the encoding and accumulation of sensory evidence during decision-making...
May 17, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Juan Carlos Bermúdez Ordoñez, Rosa María Arnaldo Valdés, Fernando Gómez Comendador
A significant challenge in global navigation satellite system (GNSS) signal processing is a requirement for a very high sampling rate. The recently-emerging compressed sensing (CS) theory makes processing GNSS signals at a low sampling rate possible if the signal has a sparse representation in a certain space. Based on CS and SVD theories, an algorithm for sampling GNSS signals at a rate much lower than the Nyquist rate and reconstructing the compressed signal is proposed in this research, which is validated after the output from that process still performs signal detection using the standard fast Fourier transform (FFT) parallel frequency space search acquisition...
May 16, 2018: Sensors
Fangqun Wang, Zhenhai Wu, Teng Jing, Qing Xu, Jinhao Yao, Jinghua Ji
Regurgitation is an abnormal condition happens when left ventricular assist devices (LVADs) operated at a low speed, which causes LVAD to fail to assist natural blood-pumping by heart and thus affects patients' health. According to the degree of regurgitation, three LVAD's regurgitation states were identified in this paper: no regurgitation, slight regurgitation and severe regurgitation. Regurgitation index ( RI ), which is presented based on the theory of dynamic closed cavity, is used to grade the regurgitation of LVAD...
October 1, 2017: Sheng Wu Yi Xue Gong Cheng Xue za Zhi, Journal of Biomedical Engineering, Shengwu Yixue Gongchengxue Zazhi
Geoffrey A Lambert, Alessandro S Zagami
Migraine is a condition without apparent pathology. Its cardinal symptom is the prolonged excruciating headache. Theories about this pain have posited pathologies which run the gamut from neural to vascular to neurovascular, but no observations have detected a plausible pathology. We believe that no pathology can be found for migraine headache because none exists. Migraine is not driven by pathology - it is driven by neural events produced by triggers - or simply by neural noise- noise that has crossed a critical threshold...
April 17, 2018: Neuropeptides
Bronisław Stec, Waldemar Susek
Determination of the signal power-to-noise power ratio on the input and output of reception systems is essential to the estimation of their quality and signal reception capability. This issue is especially important in the case when both signal and noise have the same characteristic as Gaussian white noise. This article considers the problem of how a signal-to-noise ratio is changed as a result of signal processing in the correlation receiver of a noise radar in order to determine the ability to detect weak features in the presence of strong clutter-type interference...
May 6, 2018: Sensors
Li Xiang, Guohua Rong, Jing Zhao, Zhenyan Wang, Fengfeng Shi
Evidence indicates that high-grade serous ovarian carcinoma arises from the fallopian tube, rather than ovarian surface epithelium. This is termed the 'tubal origin' theory. The aim of the present study was to compare the immunophenotype and gene expression profiling among high-grade serous ovarian carcinoma (HGSOC), fallopian tube epithelium (FTE) and ovarian surface epithelium (OSE) based on tubal origin theory, and identify the differential genes associated with ovarian carcinogenesis. A total of 61 cases of fresh tissue samples including 21 cases of HGSOC, 20 cases of OSE, and 20 cases of FTE were obtained following surgical resection...
May 2018: Oncology Letters
Frederic Zubler, Andrea Seiler, Thomas Horvath, Corinne Roth, Silvia Miano, Christian Rummel, Heidemarie Gast, Lino Nobili, Kaspar A Schindler, Claudio L Bassetti
OBJECTIVE: Large-scale connectivity, especially interhemispheric connections, plays a crucial role for recovery after stroke. Here we used methods from information theory to characterize interhemispheric information flow in wake- and sleep-EEG after cerebral ischemia. METHODS: 34 patients with unilateral ischemic stroke were included. Symbolic Transfer Entropy (STE) was applied between bipolar EEG signals on the left and the right cerebral hemisphere during polysomnographic recordings in the acute phase and 3 months after stroke...
April 17, 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Hao Suo, Xiaoqi Zhao, Zhiyu Zhang, Rui Shi, Yanfang Wu, Jinmeng Xiang, Chongfeng Guo
It is essential to simultaneously boost the luminescence intensity and thermometric sensitivity of up-converted optical thermometers towards potential biomedical sensing applications. Herein, the effects of local site symmetry on the up-conversion (UC) emission and thermal sensing ability in trigonal-phased La2O3:Er3+/Yb3+ nanospheres were qualitatively explored using cubic-phased Lu2O3 and Y2O3 with a similar shape and phonon energy as contrasts. Under 980 nm light excitation, much stronger UC emissions were detected in La2O3 samples than that in cubic Lu2O3 and Y2O3 samples, and the possible mechanisms were elaborately proposed using Eu3+ as a luminescent probe...
May 4, 2018: Nanoscale
Michael Fleyer, Moshe Horowitz
We demonstrate, theoretically and experimentally, a new method to measure small changes in the cavity length of oscillators. The method is based on the high sensitivity of the phase of forced delay-line oscillators to changes in their cavity length. The oscillator phase is directly detected by mixing the oscillator output with the injected signal. We describe a comprehensive theoretical model for studying the signal and the noise at the output of a general forced delay-line oscillator with an instantaneous gain saturation and an amplitude-to-phase conversion...
April 2, 2018: Optics Express
Hengrui Liu, Yingquan Xiong, Haixia Wang, Li Yang, Chaopeng Wang, Xiaoguang Liu, Zhidi Wu, Xiaoyun Li, Ling Ou, Ronghua Zhang, Xiaofeng Zhu
ETHNOPHARMACOLOGICAL RELEVANCE: For the past millenium, water extract from Epimedium (dried leaves of Epimedium brevicornu Maxim.) has been widely used for bone disease therapy in traditional Chinese medicine and has been reported to exhibit salutary effects on osteoporosis in clinical trials. The therapeutic effect of Epimedium is associated with the function of the brain in traditional Chinese medicine theory. STUDY AIM: To determine the potential relationship between treating osteoporosis with Epimedium and neuropeptide regulation...
April 26, 2018: Journal of Ethnopharmacology
Chang Wang, Qinyu Sun, Rui Fu, Zhen Li, Qiong Zhang
Lane Change Warning system (LCW) is exploited to alleviate driver workload and improve the safety performance of lane changes. Depending on the secure threshold, the lane change warning system could transmit caution to drivers. Although the system possesses substantial benefits, it may perturb the conventional operating of the driver and affect driver judgment if the warning threshold does not conform to the driver perception of safety. Therefore, it is essential to establish an appropriate warning threshold to enhance the accuracy rate and acceptability of the lane change warning system...
April 25, 2018: Accident; Analysis and Prevention
Sverker Sikström, Johan Hellman, Mats Dahl, Georg Stenberg, Marcus Johansson
We present the generalized signal detection theory (GSDT), where familiarity is described by a sparse binomial distribution of binary node activity rather than by normal distribution of familiarity. Items are presented in a distributed representation, where each node receives either noise only, or signal and noise. An old response (i.e., a "yes" response) is made if at least one node receives signal plus noise that is larger than the activation threshold, and item variability is determined by the distribution of activated nodes as the threshold is varied...
April 20, 2018: Cognitive Processing
Jianling Li, Guohua Ding, Yanyan Niu, Luyong Wu, Huajie Feng, Wenying He
5-Methyl-2-phenyl-2H-1,2,3-triazole-4-carboxylic acid (MPTC), a newly synthesized compound, was explored to study the structural properties and theoretical spectra by using GaussView5.0 program package and the time dependent density functional theory (TD DFT). The calculated quantum chemical values suggested that it is easy for MPTC to lose electron with weak electron accepting ability. And the results of experimental measurements on fluorescence and absorption spectra were consistent with that of the calculated spectra in great degree...
April 11, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Justus A Kromer, Steffen Märcker, Steffen Lange, Christel Baier, Benjamin M Friedrich
To navigate their surroundings, cells rely on sensory input that is corrupted by noise. In cells performing chemotaxis, such noise arises from the stochastic binding of signalling molecules at low chemoattractant concentrations. We reveal a fundamental relationship between the speed of chemotactic steering and the strength of directional fluctuations that result from the amplification of noise in a chemical input signal. This relation implies a trade-off between steering that is slow and reliable, and steering that is fast but less reliable...
April 19, 2018: PLoS Computational Biology
Todd C Jones, Kealagh Robinson, Brenna C Steel
Describing unfamiliar faces during or immediately after their presentation in a study phase can produce better recognition memory performance compared with a view-only control condition. We treated descriptions as elaborative information that is part of the study context and investigated how context retrieval influences recognition memory. Following general dual-process theories, we hypothesized that recollection would be used to recall descriptions and that description recall would influence recognition decisions, including the level of recognition confidence...
April 19, 2018: Journal of Experimental Psychology. Learning, Memory, and Cognition
Froso Sophocleous, Elena Giulia Milano, Giulia Pontecorboli, Pierpaolo Chivasso, Massimo Caputo, Cha Rajakaruna, Chiara Bucciarelli-Ducci, Costanza Emanueli, Giovanni Biglino
Bicuspid aortic valve (BAV) patients have an increased incidence of developing aortic dilation. Despite its importance, the pathogenesis of aortopathy in BAV is still largely undetermined. Nowadays, intense focus falls both on BAV morphology and progression of valvular dysfunction and on the development of aortic dilation. However, less is known about the relationship between aortic valve morphology and aortic dilation. A better understanding of the molecular pathways involved in the homeostasis of the aortic wall, including the extracellular matrix, the plasticity of the vascular smooth cells, TGFβ signaling, and epigenetic dysregulation, is key to enlighten the mechanisms underpinning BAV-aortopathy development and progression...
April 19, 2018: Journal of Cardiovascular Development and Disease
Zhen Liu, Jinping Sui, Zhenhua Wei, Xiang Li
This paper focuses on developing an anti-velocity jamming strategy that enhances the ability of a pulse-Doppler (PD) radar to detect moving targets in the presence of translational and/or micro motion velocity jamming generated by the digital radio frequency memory (DRFM) repeat jammers. The strategy adopts random pulse initial phase (RPIP) pulses as its transmitted signal and thus gets DRFM jammers not adaptable to the randomness of initial phase of the transmitted pulses in the pulse repetition interval (PRI) domain...
April 18, 2018: Sensors
Javier Segarra-Martí, Elena E Zvereva, Marco Marazzi, Johanna Brazard, Elise Dumont, Xavier Assfeld, Stefan Haacke, Marco Garavelli, Antonio Monari, Jérémie Léonard, Ivan Rivalta
Accurate characterization of the high-lying excited state manifolds of organic molecules is of fundamental importance for the interpretation of the rich response detected in time-resolved nonlinear electronic spectroscopies. Here, we have characterized the singlet excited states manifold of benzophenone (BP), a versatile organic photoinitiator and a well-known DNA photosensitizer. Benchmarks of various multiconfigurational/multireference (RASSCF/PT2) and time-dependent density functional theory (TD-DFT) approaches allowed assignments of experimental linear absorption signals of BP in the ultraviolet (UV) region, with unprecedented characterization of ground state absorptions in the far UV...
April 3, 2018: Journal of Chemical Theory and Computation
Stephen Sebastian, Wilson S Geisler
An extension of the signal-detection theory framework is described and demonstrated for two-alternative identification tasks. The extended framework assumes that the subject and an arbitrary model (or two subjects, or the same subject on two occasions) are performing the same task with the same stimuli, and that on each trial they both compute values of a decision variable. Thus, their joint performance is described by six fundamental quantities: two levels of intrinsic discriminability (d'), two values of decision criterion, and two decision-variable correlations (DVCs), one for each of the two categories of stimuli...
April 1, 2018: Journal of Vision
Christopher F Clements, Arpat Ozgul
In the face of global biodiversity declines, predicting the fate of biological systems is a key goal in ecology. One popular approach is the search for early warning signals (EWSs) based on alternative stable states theory. In this review, we cover the theory behind nonlinearity in dynamic systems and techniques to detect the loss of resilience that can indicate state transitions. We describe the research done on generic abundance-based signals of instability that are derived from the phenomenon of critical slowing down, which represent the genesis of EWSs research...
March 30, 2018: Ecology Letters
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