Journal articles on the topic 'Coherence time enhancement'
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Zhao, Zhenxing, Qi Li, Zhi Xia, and Dajing Shang. "A Single-Hydrophone Coherent-Processing Method for Line-Spectrum Enhancement." Remote Sensing 15, no. 3 (January 22, 2023): 659. http://dx.doi.org/10.3390/rs15030659.
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Improving the line-spectrum detection capability of a single hydrophone is of great significance for the passive detection of small underwater platforms. In this paper, we propose a single-hydrophone cross-power spectrum (SHCS) method based on time-domain coherence. This method uses the coherence of the line spectrum and the non-coherence of the continuous spectrum noise to obtain coherent gain and improve the signal-to-noise ratio (SNR) of the line spectrum. The effects of the input SNR, number of averaging operations, and overlap ratio on the performance of the SHCS method under a background of Gaussian white noise are simulated and analyzed. The results show that when the overlap ratio is 0 and the number of averaging operations reaches saturation, the SHCS method can achieve the best performance and about 15 dB coherence gain is obtained. The performance of the SHCS method was verified by sea experiments. Under the extremely low input SNR, in which the line spectrum was almost completely submerged in the marine environmental noise, the SHCS method can obtain about 10 dB coherence gain. Under the conventional input SNR, in which the line spectrum could be observed, the SHCS method can obtain about 13 dB coherence gain. The results of processing the radiated noise from an actual cargo ship also demonstrate the effectiveness of the SHCS method.
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Hammer, Horst, Silvia Kuny, and Antje Thiele. "Enhancing Coherence Images for Coherent Change Detection: An Example on Vehicle Tracks in Airborne SAR Images." Remote Sensing 13, no. 24 (December 9, 2021): 5010. http://dx.doi.org/10.3390/rs13245010.
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In Synthetic Aperture Radar (SAR) interferometry, one of the most widely used measures for the quality of the interferometric phase is coherence. However, in favorable conditions coherence can also be used to detect subtle changes on the ground, which are not visible in the amplitude images. For such applications, i.e., coherent change detection, it is important to have a good contrast between the unchanged (high-coherence) parts of the scene and the changed (low-coherence) parts. In this paper, an algorithm is introduced that aims at enhancing this contrast. The enhancement is achieved by a combination of careful filtering of the amplitude images and the interferometric phase image. The algorithm is applied to an airborne interferometric SAR image pair recorded by the SmartRadar experimental sensor of Hensoldt Sensors GmbH. The data were recorded during a measurement campaign over the Bann B installations of POLYGONE Range in southern Rhineland-Palatinate (Germany), with a time gap of approximately four hours between the overflights. In-between the overflights, several vehicles were moved on the site and the goal of this work is to enhance the coherence image such that the tracks of these vehicles can be detected as completely as possible in an automated way. Several coherence estimation schemes found in the literature are explored for the enhancement, as well as several commonly used speckle filters. The results of these filtering steps are evaluated visually and quantitatively, showing that the mean gray-level difference between the low-coherence tracks and their high-coherence surroundings could be enhanced by at least 28%. Line extraction is then applied to the best enhancement. The results show that the tracks can be detected much more completely using the coherence contrast enhancement scheme proposed in this paper.
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Paolo, Agustin Di, Arne L. Grimsmo, Peter Groszkowski, Jens Koch, and Alexandre Blais. "Control and coherence time enhancement of the 0–π qubit." New Journal of Physics 21, no. 4 (April 4, 2019): 043002. http://dx.doi.org/10.1088/1367-2630/ab09b0.
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Rahman, Abdul Ghaffar Abdul, Zhi Chao Ong, and Zubaidah Ismail. "Enhancement of coherence functions using time signals in Modal Analysis." Measurement 44, no. 10 (December 2011): 2112–23. http://dx.doi.org/10.1016/j.measurement.2011.08.003.
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Shreedhar Bhat, Gautam, Nikhil Shankar, and Issa Panahi. "Real-time joint dereverberation and speech enhancement for hearing aid applications using edge devices." Journal of the Acoustical Society of America 150, no. 4 (October 2021): A348. http://dx.doi.org/10.1121/10.0008541.
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In this work, we propose a joint dereverberation and speech enhancement technique for real-time applications. Speech dereverberation is based on the coherent-to-diffuse energy ratio (CDR) measured from the direction-of-arrival (DOA) dependent complex spatial coherence function. A personalized speech enhancement (SE) technique based on joint maximum a posteriori probability (JMAP) estimation that inherently accounts for the effects of changes in acoustic path and reverberation is used. The combination of these masking functions is used to enhance the speech corrupted by reverberation and noise in a frame-by-frame process. The proposed method is implemented on the smartphone (edge device), to illustrate real-time usability. The efficiency of the proposed method is evaluated using speech quality and intelligibility measures and compared with that of other benchmark techniques.
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WANG, LI, YUBING GONG, and XIU LIN. "ENHANCEMENT OF INTRINSIC SPIKING COHERENCE BY EXTERNAL NON-GAUSSIAN NOISE IN A STOCHASTIC HODGKIN–HUXLEY NEURON." Fluctuation and Noise Letters 10, no. 04 (December 2011): 359–69. http://dx.doi.org/10.1142/s0219477511000624.
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In this paper, we study the effect of external non-Gaussian noise on the temporal coherence of the intrinsic spiking induced by the channel noise in a stochastic Hodgkin–Huxley neuron. It is found that, for a sufficiently large membrane patch, the intrinsic spiking coherence can be enhanced by the proper values of non-Gaussian noise's strength, correlation time, or deviation from Gaussian distribution. And that the intrinsic spiking can exhibit coherence resonance when the noise's strength is optimal. This implies that the channel noise-induced intrinsic spiking may become more or the most ordered in time with the assistance of the external non-Gaussian noise. These results show that the external non-Gaussian noise can play a constructive role for improving the time precision of information processing in stochastic neurons.
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Nakano, Tamami, Haruhisa Ota, Nobumasa Kato, and Shigeru Kitazawa. "Deficit in visual temporal integration in autism spectrum disorders." Proceedings of the Royal Society B: Biological Sciences 277, no. 1684 (December 2, 2009): 1027–30. http://dx.doi.org/10.1098/rspb.2009.1713.
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Individuals with autism spectrum disorders (ASD) are superior in processing local features. Frith and Happe conceptualize this cognitive bias as ‘weak central coherence’, implying that a local enhancement derives from a weakness in integrating local elements into a coherent whole. The suggested deficit has been challenged, however, because individuals with ASD were not found to be inferior to normal controls in holistic perception. In these opposing studies, however, subjects were encouraged to ignore local features and attend to the whole. Therefore, no one has directly tested whether individuals with ASD are able to integrate local elements over time into a whole image. Here, we report a weakness of individuals with ASD in naming familiar objects moved behind a narrow slit, which was worsened by the absence of local salient features. The results indicate that individuals with ASD have a clear deficit in integrating local visual information over time into a global whole, providing direct evidence for the weak central coherence hypothesis.
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AWSCHALOM, DAVID D. "CONTROLLING SPIN COHERENCE WITH SEMICONDUCTOR NANOSTRUCTURES." International Journal of Modern Physics B 22, no. 01n02 (January 20, 2008): 111–12. http://dx.doi.org/10.1142/s0217979208046165.
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We present two emerging opportunities for manipulating and communicating coherent spin states in semiconductors. First, we show that semiconductor microcavities offer unique means of controlling light-matter interactions in confined geometries, resulting in a wide range of applications in optical communications and inspiring proposals for quantum information processing and computational schemes. Studies of spin dynamics in microcavities — a new and promising research field — have revealed novel effects such as polarization beats, stimulated spin scattering, and giant Faraday rotation. Here, we study the electron spin dynamics in optically-pumped GaAs microdisk lasers with quantum wells and interface-fluctuation quantum dots in the active region. In particular, we examine how the electron spin dynamics are modified by the stimulated emission in the disks, and observe an enhancement of the spin coherence time when the optical excitation is in resonance with a high quality ( Q ~ 5000) lasing mode.1 This resonant enhancement, contrary to expectations from the observed trend in the carrier recombination time, is then manipulated by altering the cavity design and dimensions. In analogy to devices based on excitonic coherence, this ability to engineer coherent interactions between electron spins and photons may provide novel pathways towards spin dependent quantum optoelectronics. In a second example, the nitrogen-vacancy (N-V) center in diamond has garnered interest as a room-temperature solid-state system not only for exploring electronic and nuclear spin phenomena but also as a candidate for spin-based quantum information processing. Spin coherence times of up to 50 microseconds have been reported for ensembles of N-V centers and a two-qubit gate utilizing the electron spin of a N-V center and the nuclear spin of a nearby C-13 atom has been demonstrated. Here, we present experiments using angle-resolved magneto-photoluminescence microscopy to investigate anisotropic spin interactions of single N-V centers in diamond at room temperature.2 Negative peaks in the photoluminescence intensity are observed as a function of both magnetic field magnitude and angle, and can be explained by coherent spin precession and anisotropic relaxation at spin-level anticrossings. Additionally, precise field alignment with the symmetry axis of a single N-V center reveals the resonant magnetic dipolar coupling of a single "bright" electron spin of an N-V center to small numbers of "dark" spins of nitrogen defects in its immediate vicinity, which are otherwise undetected by photoluminescence. Most recently, we are exploring the possibility of utilizing this magnetic dipole coupling between bright and dark spins to couple two spatially separated single N-V center spins by means of intermediate nitrogen spins. Note from Publisher: This article contains the abstract only.
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Ding, Xueli, Bing Jia, Yuye Li, and Huaguang Gu. "Enhancement of coherence resonance induced by inhibitory autapse in Hodgkin–Huxley model." International Journal of Modern Physics B 35, no. 07 (March 20, 2021): 2150110. http://dx.doi.org/10.1142/s0217979221501101.
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Inhibitory effect often suppresses electronic activities of the nervous system. In this paper, the inhibitory autapse is identified to enhance the degree of coherence resonance (CR) induced by noise in the Hodgkin–Huxley (HH) model with Hopf bifurcation from resting state to spiking with nearly fixed period [Formula: see text]. Without noise, the inhibitory autapse can induce a post inhibitory rebound (PIR) spike from the resting state at time delay approximating [Formula: see text] and can inhibit a spike of spiking at time delay approximating [Formula: see text]. In the presence of noise, CR characterized by maximal value of power spectrum of spike trains appears in a wide range of both time delay and conductance of autapse. With increasing autaptic conductance, CR degree becomes stronger for time delay approximating [Formula: see text] plus integer (from 0) multiples of [Formula: see text], because the inhibitory autaptic current pulses can induce more PIR spikes. The decrease of CR degree at time delay approximating integer (from 1) multiples of [Formula: see text] can be explained by the inhibition effect. The promotion of coherence resonance degree and the underlying PIR mechanism induced by inhibitory self-feedback extends the paradoxical phenomenon of inhibitory autapse to stochastic system and presents potential measures to modulate CR degree and information processing.
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Abd-Elmoniem, K. Z., A. B. M. Youssef, and Y. M. Kadah. "Real-time speckle reduction and coherence enhancement in ultrasound imaging via nonlinear anisotropic diffusion." IEEE Transactions on Biomedical Engineering 49, no. 9 (September 2002): 997–1014. http://dx.doi.org/10.1109/tbme.2002.1028423.
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Xie, Ping, Yingying Hao, Xiaoling Chen, Ziqiang Jin, Shengcui Cheng, Xin Li, Lanxiang Liu, Yi Yuan, and Xiaoli Li. "Enhancement of functional corticomuscular coupling after transcranial ultrasound stimulation in mice." Journal of Neural Engineering 19, no. 2 (March 29, 2022): 026014. http://dx.doi.org/10.1088/1741-2552/ac5c8b.
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Abstract Objective. Transcranial ultrasound stimulation (TUS), a large penetration depth and high spatial resolution technology, has developed rapidly in recent years. This study aimed to explore and evaluate the neuromodulation effects of TUS on mouse motor neural circuits under different parameters. Approach. Our study used functional corticomuscular coupling (FCMC) as an index to explore the modulation mechanism for movement control under different TUS parameters (intensity [ I sppa ] and stimulation duration). We collected local field potential (LFP) and tail electromyographic (EMG) data under TUS in healthy mice and then introduced the time-frequency coherence method to analyze the FCMC before and after TUS in the time-frequency domain. After that, we defined the relative coherence area to quantify the coherence between LFP and EMG under TUS. Main results. The FCMC at theta, alpha, beta, and gamma bands was enhanced after TUS, and the neuromodulation efficacy mainly occurred in the lower frequency band (theta and alpha band). After TUS with different parameters, the FCMC in all selected frequency bands showed a tendency of increasing first and then decreasing. Further analysis showed that the maximum coupling value of theta band appeared from 0.2 to 0.4 s, and that the maximum coupling value in alpha and gamma band appeared from 0 to 0.2 s. Significance. The aforementioned results demonstrate that FCMC in the motor cortex could be modulated by TUS. We provide a theoretical basis for further exploring the modulation mechanism of TUS parameters and clinical application.
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Alqahtani, Faisal, and Abdullatif A. Al-Shuhail. "Imaging subtle faults using azimuthal coherence attribute: A case study from Central Saudi Arabia." GeoArabia 17, no. 4 (October 1, 2012): 43–54. http://dx.doi.org/10.2113/geoarabia170443.
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ABSTRACT The coherence attribute is an edge detection method that is widely used for interpreting faults on 3-D seismic time slices. The traditional coherence attribute is calculated on migrated volumes using traces from all available azimuths. It has recently been shown that calculating coherence along specific azimuths can enhance the detection of faults running perpendicular to those azimuths. In this study, we applied azimuthal coherence attribute analysis on a 3-D seismic data set from a gas field in Central Saudi Arabia. We generated four migrated 3-D data volumes sorted by azimuth in addition to a conventional full-azimuth volume. We then calculated the coherence attribute for all volumes and compared each azimuthal coherence volume to the conventional full-azimuth coherence volume. The azimuthal coherence results exhibited an improved definition for faults whose strikes are perpendicular to the sorting azimuth. More specifically, systems of NW-trending discontinuities were imaged more clearly in the NE-SW oriented coherence volume than it was in the full-azimuth coherence volume. The reason for this enhancement is the fact that seismic waves tend to avoid passing through the fault when they propagate parallel to the fault strike therefore missing the effects of the fault while they must pass through the fault when propagating perpendicular to the fault strike which results in better illumination of the fault.
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Zhu, Dai Zhu, and Wen Hua Huang. "The Technology of Line-Spectrum Enhancement Based on Image Processing." Advanced Materials Research 429 (January 2012): 308–12. http://dx.doi.org/10.4028/www.scientific.net/amr.429.308.
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Time-frequency spectrogram analysis is a basic method in passive radar and sonar. It′s necessary to enhance the line-spectrum to improve the performance in low SNR(Signal to Noise Ratio) and strong interference presented that wider detecting range and long reacting time can be obtained. The traditional line-spectrum enhancing technology based on signal′s coherence can′t work well in very low SNR, and the performance will drop sharply when the line-spectrums are close in frequencies or the number of line-spectrums increases. A new method which combines image processing with signal processing is brought out to overcome these defects. It can work well when the SNR in frequency domain is close to 0dB,which is much lower than ALE and other traditional technology. The results derived from simulation and trial data analysis show that it′s stable and can be applied in the field with line-spectrums.
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Kanngiesser, Jonas, and Bernhard Roth. "Wavefront Shaping Concepts for Application in Optical Coherence Tomography—A Review." Sensors 20, no. 24 (December 9, 2020): 7044. http://dx.doi.org/10.3390/s20247044.
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Optical coherence tomography (OCT) enables three-dimensional imaging with resolution on the micrometer scale. The technique relies on the time-of-flight gated detection of light scattered from a sample and has received enormous interest in applications as versatile as non-destructive testing, metrology and non-invasive medical diagnostics. However, in strongly scattering media such as biological tissue, the penetration depth and imaging resolution are limited. Combining OCT imaging with wavefront shaping approaches significantly leverages the capabilities of the technique by controlling the scattered light field through manipulation of the field incident on the sample. This article reviews the main concepts developed so far in the field and discusses the latest results achieved with a focus on signal enhancement and imaging.
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Zhang, Han Hua, Yu Ming Wang, and Qian Song. "Application of PCA-CFAR-MNF to Image Enhancement for a UGV FLGPR." Applied Mechanics and Materials 190-191 (July 2012): 656–60. http://dx.doi.org/10.4028/www.scientific.net/amm.190-191.656.
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The UGV (Unmanned Ground Vehicle) FLGPR (Forward-Looking Ground Penetrating Radar) imaging model spatially variable characteristics lead to the relatively low image SCR (Signal-Clutter Ratio). In order to improve the image quality and improve the SCR, the coherence properties of the target in image sequences is used for image enhancement. That is, images from the same region at different time sequence are enhanced two times. First of all, CFAR (Constant False Alarm Rate) is a preliminary step to enhance the image sequence, and then PCA-CFAR-MNF enhancement algorithm is proposed: according to the iterative nature of the MNF (Maximum Noise Fraction), PCA (Principal Component Analysis) method is first used to transform selecting and then CFAR detection is used to estimate the image background in the iteration,. The measured data show that the proposed method not only keeping the target characteristics, but also have remarkable image enhancement effect, and have greatly improved SCR.
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Castellanos, Nazareth P., Eduardo Malmierca, Angel Nuñez, and Valeri A. Makarov. "Corticofugal Modulation of the Tactile Response Coherence of Projecting Neurons in the Gracilis Nucleus." Journal of Neurophysiology 98, no. 5 (November 2007): 2537–49. http://dx.doi.org/10.1152/jn.00815.2007.
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Precise and reproducible spike timing is one of the alternatives of the sensory stimulus encoding. We test coherence (repeatability) of the response patterns elicited in projecting gracile neurons by tactile stimulation and its modulation provoked by electrical stimulation of the corticofugal feedback from the somatosensory (SI) cortex. To gain the temporal structure we adopt the wavelet-based approach for quantification of the functional stimulus–neural response coupling. We show that the spontaneous firing patterns (when they exist) are essentially random. Tactile stimulation of the neuron receptive field strongly increases the spectral power in the stimulus and 5- to 15-Hz frequency bands. However, the functional coupling (coherence) between the sensory stimulus and the neural response exhibits ultraslow oscillation (0.07 Hz). During this oscillation the stimulus coherence can temporarily fall below the statistically significant level, i.e., the functional stimulus–response coupling may be temporarily lost for a single neuron. We further demonstrate that electrical stimulation of the SI cortex increases the stimulus coherence for about 60% of cells. We find no significant correlation between the increment of the firing rate and the stimulus coherence, but we show that there is a positive correlation with the amplitude of the peristimulus time histogram. The latter argues that the observed facilitation of the neural response by the corticofugal pathway, at least in part, may be mediated through an appropriate ordering of the stimulus-evoked firing pattern, and the coherence enhancement is more relevant in gracilis nucleus than an increase of the number of spikes elicited by the tactile stimulus.
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Yilmaz, Ergin, Veli Baysal, and Mahmut Ozer. "Enhancement of temporal coherence via time-periodic coupling strength in a scale-free network of stochastic Hodgkin–Huxley neurons." Physics Letters A 379, no. 26-27 (August 2015): 1594–99. http://dx.doi.org/10.1016/j.physleta.2015.04.016.
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Yun, Jungmi, and Hyoung Sook Park. "THE EFFECT OF SENSE OF COHERENCE ENHANCEMENT PROGRAM BASED ON SALUTOGENESIS FOR ELDERLY WITH METABOLIC SYNDROME." Innovation in Aging 3, Supplement_1 (November 2019): S142. http://dx.doi.org/10.1093/geroni/igz038.513.
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Abstract This study aimed to develop and verify a sense of coherence (SOC) enhancement program based on salutogenesis for elderly with metabolic syndrome. This study was a quasi-experimental study. The inclusion criteria were patients with metabolic syndrome aged 60 or over who visited the outpatient department of a university hospital and a public health center located in an urban area. The intervention group (n=24) attended the SOC enhancement program. The health promotion theoretical framework, salutogenesis, provided the program structure and conceptual framework of this study. This program included comprehensibility, manageability, and meaningfulness which were core concepts of salutogenesis and consisted of multiple tailored behavior interventions composed of education, Tai-Chi exercises, individual activities, self-monitoring, self-help groups, and individual counseling. This program was provided once a week over 10 weeks, but Tai-Chi exercise was conducted twice a week. The control group (n=25) was provided with general health information once. The interactions between groups and measurement time showed significant differences in self-efficacy (p=.001), perceived social support (p<.001), SOC (p<.001), health behavior (p=.010), and the physical health-related quality of life (p=.001). The metabolic-related physiological indicators showed significant improvement in total cholesterol (p=.004) and LDL-cholesterol (p=.009). This study showed that the SOC enhancement program strengthened the self-efficacy, social support, and SOC in the elderly with metabolic syndrome, improved the health behavior, and was effective in improving some metabolic-related physiological indicators. Based on the results of this study, I suggest to expand the scope of the sense of coherence program and conduct the intervention longer.
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Tao, Zhifu, Wenping Zhang, Mudi Yao, Yuanfu Zhong, Yanan Sun, Xiu-Miao Li, Jin Yao, Qin Jiang, Peirong Lu, and Zhenhua Wang. "A Joint Model for Macular Edema Analysis in Optical Coherence Tomography Images Based on Image Enhancement and Segmentation." BioMed Research International 2021 (February 17, 2021): 1–9. http://dx.doi.org/10.1155/2021/6679556.
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Optical coherence tomography (OCT) provides the visualization of macular edema which can assist ophthalmologists in the diagnosis of ocular diseases. Macular edema is a major cause of vision loss in patients with retinal vein occlusion (RVO). However, manual delineation of macular edema is a laborious and time-consuming task. This study proposes a joint model for automatic delineation of macular edema in OCT images. This model consists of two steps: image enhancement using a bioinspired algorithm and macular edema segmentation using a Gaussian-filtering regularized level set (SBGFRLS) algorithm. We then evaluated the delineation efficiency using the following parameters: accuracy, precision, sensitivity, specificity, Dice’s similarity coefficient, IOU, and kappa coefficient. Compared with the traditional level set algorithms, including C-V and GAC, the proposed model had higher efficiency in macular edema delineation as shown by reduced processing time and iteration times. Moreover, the accuracy, precision, sensitivity, specificity, Dice’s similarity coefficient, IOU, and kappa coefficient for macular edema delineation could reach 99.7%, 97.8%, 96.0%, 99.0%, 96.9%, 94.0%, and 96.8%, respectively. More importantly, the proposed model had comparable precision but shorter processing time compared with manual delineation. Collectively, this study provides a novel model for the delineation of macular edema in OCT images, which can assist the ophthalmologists for the screening and diagnosis of retinal diseases.
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Sun, Yankui, Tian Zhang, Yue Zhao, and Yufan He. "3D automatic segmentation method for retinal optical coherence tomography volume data using boundary surface enhancement." Journal of Innovative Optical Health Sciences 09, no. 02 (March 2016): 1650008. http://dx.doi.org/10.1142/s1793545816500085.
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With the introduction of spectral-domain optical coherence tomography (SD-OCT), much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, there is a critical need for the development of three-dimensional (3D) segmentation methods for processing these data. We present here a novel 3D automatic segmentation method for retinal OCT volume data. Briefly, to segment a boundary surface, two OCT volume datasets are obtained by using a 3D smoothing filter and a 3D differential filter. Their linear combination is then calculated to generate new volume data with an enhanced boundary surface, where pixel intensity, boundary position information, and intensity changes on both sides of the boundary surface are used simultaneously. Next, preliminary discrete boundary points are detected from the A-Scans of the volume data. Finally, surface smoothness constraints and a dynamic threshold are applied to obtain a smoothed boundary surface by correcting a small number of error points. Our method can extract retinal layer boundary surfaces sequentially with a decreasing search region of volume data. We performed automatic segmentation on eight human OCT volume datasets acquired from a commercial Spectralis OCT system, where each volume of datasets contains 97 OCT B-Scan images with a resolution of [Formula: see text] (each B-Scan comprising 512 A-Scans containing 496 pixels); experimental results show that this method can accurately segment seven layer boundary surfaces in normal as well as some abnormal eyes.
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Li, Gang, Shihong Zhou, Zhen Kong, and Mengyuan Guo. "Closed-Loop Attention Restoration Theory for Virtual Reality-Based Attentional Engagement Enhancement." Sensors 20, no. 8 (April 14, 2020): 2208. http://dx.doi.org/10.3390/s20082208.
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Today, as media and technology multitasking becomes pervasive, the majority of young people face a challenge regarding their attentional engagement (that is, how well their attention can be maintained). While various approaches to improve attentional engagement exist, it is difficult to produce an effect in younger people, due to the inadequate attraction of these approaches themselves. Here, we show that a single 30-min engagement with an attention restoration theory (ART)-inspired closed-loop software program (Virtual ART) delivered on a consumer-friendly virtual reality head-mounted display (VR-HMD) could lead to improvements in both general attention level and the depth of engagement in young university students. These improvements were associated with positive changes in both behavioral (response time and response time variability) and key electroencephalography (EEG)-based neural metrics (frontal midline theta inter-trial coherence and parietal event-related potential P3b). All the results were based on the comparison of the standard Virtual ART tasks (control group, n = 15) and closed-loop Virtual ART tasks (treatment group, n = 15). This study provides the first case of EEG evidence of a VR-HMD-based closed-loop ART intervention generating enhanced attentional engagement.
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Al-Shargie, Fares, Usman Tariq, Omnia Hassanin, Hasan Mir, Fabio Babiloni, and Hasan Al-Nashash. "Brain Connectivity Analysis Under Semantic Vigilance and Enhanced Mental States." Brain Sciences 9, no. 12 (December 9, 2019): 363. http://dx.doi.org/10.3390/brainsci9120363.
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In this paper, we present a method to quantify the coupling between brain regions under vigilance and enhanced mental states by utilizing partial directed coherence (PDC) and graph theory analysis (GTA). The vigilance state is induced using a modified version of stroop color-word task (SCWT) while the enhancement state is based on audio stimulation with a pure tone of 250 Hz. The audio stimulation was presented to the right and left ears simultaneously for one-hour while participants perform the SCWT. The quantification of mental states was performed by means of statistical analysis of indexes based on GTA, behavioral responses of time-on-task (TOT), and Brunel Mood Scale (BRMUS). The results show that PDC is very sensitive to vigilance decrement and shows that the brain connectivity network is significantly reduced with increasing TOT, p < 0.05. Meanwhile, during the enhanced state, the connectivity network maintains high connectivity as time passes and shows significant improvements compared to vigilance state. The audio stimulation enhances the connectivity network over the frontal and parietal regions and the right hemisphere. The increase in the connectivity network correlates with individual differences in the magnitude of the vigilance enhancement assessed by response time to stimuli. Our results provide evidence for enhancement of cognitive processing efficiency with audio stimulation. The BRMUS was used to evaluate the emotional states of vigilance task before and after using the audio stimulation. BRMUS factors, such as fatigue, depression, and anger, significantly decrease in the enhancement group compared to vigilance group. On the other hand, happy and calmness factors increased with audio stimulation, p < 0.05.
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Li, Yan, Songhua Yan, Jianya Gong, and Fanku Zeng. "SNR Enhancement of Back Scattering Signals for Bistatic Radar Based on BeiDou GEO Satellites." Remote Sensing 13, no. 7 (March 25, 2021): 1254. http://dx.doi.org/10.3390/rs13071254.
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Using scattering signals of the global navigation satellite system (GNSS) for target detection has become one of the research hotspots. This technology faces the difficulty of low signal-to-noise ratio (SNR) target echoes. Since BeiDou geostationary orbit (GEO) satellites provide the opportunity to form a bistatic radar with some advantages, such as fixed coverage area and quasi monostatic configuration to avoid the interference from the direct signals, the target echoes may have regular phases that are beneficial to SNR enhancement. This study uses BeiDou GEO satellites and ground fixed receivers to form a bistatic radar and analyzes the phase changes in the reflected signal caused by the target, then gives two methods for SNR enhancement corresponding to two applications: deformation monitoring and ship detection. This paper first introduces the basic signal processing including the intermediate frequency (IF) signal collector and the range compression in the software receiver, then describes the basic SNR enhancement method, i.e., increasing coherence integration time (CIT), and shows its limitation by two target cases: static metal reflector on the land and ships in the water. After that, this study provides an improved SNR enhancement method based on Doppler and range compensation in the moving ship detection case. The experiment shows that by the SNR enhancement, the SNRs of target echo signals in range/Doppler domain increase more than 4 dB on average. This study also demonstrates the bistatic radar’s potential for monitoring surface deformation.
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Chilson, P. B., S. Kirkwood, and I. Häggström. "Frequency domain interferometry mode observations of PMSE using the EISCAT VHF radar." Annales Geophysicae 18, no. 12 (December 31, 2000): 1599–612. http://dx.doi.org/10.1007/s00585-001-1599-8.
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Abstract. During the summer of 1997 investigations into the nature of polar mesosphere summer echoes (PMSE) were conducted using the European incoherent scatter (EISCAT) VHF radar in Norway. The radar was operated in a frequency domain interferometry (FDI) mode over a period of two weeks to study the frequency coherence of the returned radar signals. The operating frequencies of the radar were 224.0 and 224.6 MHz. We present the first results from the experiment by discussing two 4-h intervals of data collected over two consecutive nights. During the first of the two days an enhancement of the FDI coherence, which indicates the presence of distinct scattering layers, was found to follow the lower boundary of the PMSE. Indeed, it is not unusual to observe that the coherence values are peaked around the heights corresponding to both the lower- and upper-most boundaries of the PMSE layer and sublayers. A Kelvin-Helmholtz mechanism is offered as one possible explanation for the layering structure. Additionally, our analysis using range-time-pseudocolor plots of signal-to-noise ratios, spectrograms of Doppler velocity, and estimates of the positions of individual scattering layers is shown to be consistent with the proposition that upwardly propagating gravity waves can become steepened near the mesopause.Key words: Ionosphere (polar ionosphere) · Meteorology and Atmospheric Dynamics (middle atmosphere dynamics) · Radio Science (Interferometry)
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Graham, David G., and Matthew R. Banks. "Advances in upper gastrointestinal endoscopy." F1000Research 4 (December 16, 2015): 1457. http://dx.doi.org/10.12688/f1000research.6961.1.
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The rapidly moving technological advances in gastrointestinal endoscopy have enhanced an endoscopist’s ability to diagnose and treat lesions within the gastrointestinal tract. The improvement in image quality created by the advent of high-definition and magnification endoscopy, alongside image enhancement, produces images of superb quality and detail that empower the endoscopist to identify important lesions that have previously been undetectable. Additionally, we are now seeing technologies emerge, such as optical coherence tomography and confocal laser endomicroscopy, that allow the endoscopist to visualize individual cells on a microscopic level and provide a real time,in vivohistological assessment. Within this article we discuss these technologies, as well as some of the results from their early use in clinical studies.
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Luo, Lu, Na Xu, Qian Wang, and Liang Li. "Disparity in interaural time difference improves the accuracy of neural representations of individual concurrent narrowband sounds in rat inferior colliculus and auditory cortex." Journal of Neurophysiology 123, no. 2 (February 1, 2020): 695–706. http://dx.doi.org/10.1152/jn.00284.2019.
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The central mechanisms underlying binaural unmasking for spectrally overlapping concurrent sounds, which are unresolved in the peripheral auditory system, remain largely unknown. In this study, frequency-following responses (FFRs) to two binaurally presented independent narrowband noises (NBNs) with overlapping spectra were recorded simultaneously in the inferior colliculus (IC) and auditory cortex (AC) in anesthetized rats. The results showed that for both IC FFRs and AC FFRs, introducing an interaural time difference (ITD) disparity between the two concurrent NBNs enhanced the representation fidelity, reflected by the increased coherence between the responses evoked by double-NBN stimulation and the responses evoked by single NBNs. The ITD disparity effect varied across frequency bands, being more marked for higher frequency bands in the IC and lower frequency bands in the AC. Moreover, the coherence between IC responses and AC responses was also enhanced by the ITD disparity, and the enhancement was most prominent for low-frequency bands and the IC and the AC on the same side. These results suggest a critical role of the ITD cue in the neural segregation of spectrotemporally overlapping sounds. NEW & NOTEWORTHY When two spectrally overlapped narrowband noises are presented at the same time with the same sound-pressure level, they mask each other. Introducing a disparity in interaural time difference between these two narrowband noises improves the accuracy of the neural representation of individual sounds in both the inferior colliculus and the auditory cortex. The lower frequency signal transformation from the inferior colliculus to the auditory cortex on the same side is also enhanced, showing the effect of binaural unmasking.
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Shen, Hongyan, Yueying Yan, Xinxin Li, Xin Wan, Qin Li, and Yidong Li. "Enhancement of GPR Diffracted Waves Processing: A Case Study from Taiyuan, China." Journal of Environmental and Engineering Geophysics 24, no. 2 (June 2019): 237–47. http://dx.doi.org/10.2113/jeeg24.2.237.
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Mined-out areas, caves, voids and cavities usually appear as diffracted waves on ground penetrating radar (GPR) profiles. Therefore, the complete extraction of diffracted waves forms the foundation of the efficient usage of the GPR technique in geological surveys. We propose a method of enhancing GPR diffracted waves via singular value decomposition (SVD) filtering and establish an effective GPR data processing flowchart. First, the shallow and deep signal energies were controlled within a certain dynamic range by energy scaling in the traces. Next, the SVD filtering process was employed to suppress air waves and multiples with better transverse coherence and to extract GPR diffracted waves. Third, background noise was suppressed via band-pass filtering to further improve the signal-to-noise ratio (SNR) of the GPR data. Finally, fitting a diffraction time-distance hyperbola allow us to obtain a diffraction velocity. Constant velocity migration processing for the diffracted waves was based on the Kirchhoff migration technique. The feasibility and effectiveness of this GPR processing technique were verified with the discovery of geological flaws beneath the Mengshan Giant Buddha in China during a cavity survey. Our proposed flowchart efficiently extracts GPR diffracted waves and increases the data SNR. The resulting images are more readily interpreted within the local geological context.
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Murray, Brendan P., and Miguel D. Bustamante. "Energy flux enhancement, intermittency and turbulence via Fourier triad phase dynamics in the 1-D Burgers equation." Journal of Fluid Mechanics 850 (July 6, 2018): 624–45. http://dx.doi.org/10.1017/jfm.2018.454.
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We present a theoretical and numerical study of Fourier-space triad phase dynamics in the one-dimensional stochastically forced Burgers equation at Reynolds number $Re\approx 2.7\times 10^{4}$. We demonstrate that Fourier triad phases over the inertial range display a collective behaviour characterised by intermittent periods of synchronisation and alignment, reminiscent of the Kuramoto model (Chemical Oscillations, Waves, and Turbulence, Springer, 1984) and directly related to collisions of shocks in physical space. These periods of synchronisation favour efficient energy fluxes across the inertial range towards small scales, resulting in strong bursts of dissipation and enhanced coherence of the Fourier energy spectrum. The fast time scale of the onset of synchronisation relegates energy dynamics to a passive role: this is further examined using a reduced system with the Fourier amplitudes fixed in time – a phase-only model. We show that intermittent triad phase dynamics persists without amplitude evolution and we broadly recover many of the characteristics of the full Burgers system. In addition, for both full Burgers and phase-only systems the physical-space velocity statistics reveals that triad phase alignment is directly related to the non-Gaussian statistics typically associated with structure-function intermittency in turbulent systems.
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Volvach, A., and G. Kurbasova. "MODEL OF INSOLATION OF THE EARTH SURFACE IN THE KARA-DAG LOCALITY ACCORDING TO SSE DATA." Visnyk of Taras Shevchenko National University of Kyiv. Geology, no. 2 (85) (2019): 51–58. http://dx.doi.org/10.17721/1728-2713.85.07.
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Anomalous enhancement of solar insolation of the earth's surface in the presence of foci of excitation in its depths can cause a response at local sites. Such foci include, first of all, recent and past (retro) volcanoes, such as the ancient volcano on the territory of Kara-Dag in the Crimea. The authors of this article have found increased, in comparison with other localities of the Crimea, general insolation according to SSE. According to the 22-year linear trend, the rate of insolation growth falling on the earth's surface at Kara-Dag has been calculated, which is 2,69 kWh/m2 per century, being more than 2 times higher than insolation growth in other areas of the Crimea. This phenomenon has been the subject of discussion, and additional research is needed, both on the geological structure of Kara-Dag and on the impact of external and internal forces. At the stage of studying the structure of data on insolation of the earth's surface at Kara-Dag, we have built a 6-order sine-wave model. The most powerful (amplitudes more than an order of magnitude higher than the noise level) regular oscillations on the 22-year interval have periods of 365,3 and 365,7 days. Statistical estimates of the degree of approximation by a sinusoidal model (R2 = 0,9, RMSE = 0,7) indicate that, in addition to regular periodic oscillations, there are irregular fluctuations in the data at time intervals determined by a continuous time-frequency wavelet analysis. The wavelet transformation graph highlights the interval of insolation energy growth at Kara-Dag locality after 1995. In order to analyze the statistical relationship of changes in local insolation of the Earth's surface with the Earth's rotation around the axis and its orbital movement, solar activity and global temperature, autoregression models of the power spectral density were calculated using which coherent oscillations were found between variations in Kara-Dag paragraph and variations in the data: on the length of the day (LOD) with a period of 11,8 years and a square modulus of coherence of 0,85; about solar activity with periods of 10,5, 3,6 years and a squared coherence modulus of 0,8 and 0,85; about global temperature indices with periods of 2,3, 3,5 years and squares of coherence modulus 0,7 and 0,9, respectively. The increased growth of insolation and the temperature of the earth at Kara-Dag locality that we found requires additional research and observations.
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Dash, Sonali, P. Satish Rama Chowdary, V. V. S. S. S. Chakravarthy, C. V. Gopala Raju, Gupteswar Sahu, KJN Siva Charan, and Y. Umamaheshwar. "Real Time Retinal Optic Disc Segmentation via Guided filter and Discrete Wavelet Transform." Journal of Physics: Conference Series 2312, no. 1 (August 1, 2022): 012007. http://dx.doi.org/10.1088/1742-6596/2312/1/012007.
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Abstract In the world, glaucoma is the one of the main causes for loosing vision. Optical Coherence Tomography or fundus camera is utilized to capture the optic disc and optic cup images. For the detection of glaucoma and afterwards monitoring the patients, investigation of the head of optic nerve or cup-to-disc ratio (CDR) is an important factor. For computing the CDR value, segmentation of optic disc and optic cup are utilized for the isolation of the relevant parts of the fundus image. Even though ophthalmologists are computing the CDR value physically, however, it limits the identification of glaucoma at the early stage. The accurate value of CDR is hard to find out if the optic cup and optic disc are not well defined properly. Thus, this paper has suggested a combined model of Guided filter and Discrete Wave Transform (DWT) for the enhancement and OD segmentation. Hysteresis thresholding is utilized for the optic cup segmentation. A set of 50 images of 25 patients are obtained from Visakha Eye Hospital, Visakhapatnam, India, is used to verify the performance of the suggested model. The recommended approach is also verified on the glaucoma subset of High-Resolution Fundus (HRF) database. The experimental results of both the databases demonstrate that the CDR value is computed accurately with low computational time.
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Lim, Zi Li, Kai Leong Chong, Guang-Yu Ding, and Ke-Qing Xia. "Quasistatic magnetoconvection: heat transport enhancement and boundary layer crossing." Journal of Fluid Mechanics 870 (May 14, 2019): 519–42. http://dx.doi.org/10.1017/jfm.2019.232.
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We present a numerical study of quasistatic magnetoconvection in a cubic Rayleigh–Bénard (RB) convection cell subjected to a vertical external magnetic field. For moderate values of the Hartmann number $Ha$ (characterising the strength of the stabilising Lorentz force), we find an enhancement of heat transport (as characterised by the Nusselt number $Nu$). Furthermore, a maximum heat transport enhancement is observed at certain optimal $Ha_{opt}$. The enhanced heat transport may be understood as a result of the increased coherence of the thermal plumes, which are elementary heat carriers of the system. To our knowledge this is the first time that a heat transfer enhancement by the stabilising Lorentz force in quasistatic magnetoconvection has been observed. We further found that the optimal enhancement may be understood in terms of the crossing of the thermal and the momentum boundary layers (BL) and the fact that temperature fluctuations are maximum near the position where the BLs cross. These findings demonstrate that the heat transport enhancement phenomenon in the quasistatic magnetoconvection system belongs to the same universality class of stabilising–destabilising (S–D) turbulent flows as the systems of confined Rayleigh–Bénard (CRB), rotating Rayleigh–Bénard (RRB) and double-diffusive convection (DDC). This is further supported by the findings that the heat transport, boundary layer ratio and temperature fluctuations in magnetoconvection at the boundary layer crossing point are similar to the other three cases. A second type of boundary layer crossing is also observed in this work. In the limit of $Re\gg Ha$, the (traditionally defined) viscous boundary $\unicode[STIX]{x1D6FF}_{v}$ is found to follow a Prandtl–Blasius-type scaling with the Reynolds number $Re$ and is independent of $Ha$. In the other limit of $Re\ll Ha$, $\unicode[STIX]{x1D6FF}_{v}$ exhibits an approximate ${\sim}Ha^{-1}$ dependence, which has been predicted for a Hartmann boundary layer. Assuming the inertial term in the momentum equation is balanced by both the viscous and Lorentz terms, we derived an expression $\unicode[STIX]{x1D6FF}_{v}=H/\sqrt{c_{1}Re^{0.72}+c_{2}Ha^{2}}$ (where $H$ is the height of the cell) for all values of $Re$ and $Ha$, which fits the obtained viscous boundary layer well.
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Tu Anh, Le, Nguyen Thi Thu Ha, Nguyen Thanh Tra, Bui Hai Ninh, Nguyen Khac Tiep, and Ninh The Son. "Chemical constituents from the stem barks of polyscias serrata balf." Vietnam Journal of Science and Technology 60, no. 6 (December 30, 2022): 966–73. http://dx.doi.org/10.15625/2525-2518/16656.
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Plants of the genus Polyscias (the family Araliaceae) are represented as perennial shrubs and are commonly cultivated in southeastern Asia and the Pacific regions. Pharmacological studies revealed that Polyscias crude extracts and their isolated compounds exhibited a variety of biological activity, such as antibacterial, antifungal, cytotoxic, immuno-stimulant, wound healing and anti-asthmatic activities. For the first time, phytochemical study on the methanol (MeOH) extract of the stem barks of Vietnamese species Polyscias serrata Balf. (locally named Dinh lang rang) resulted in the isolation and NMR (Nuclear Magnetic Resonance)-determination of six compounds 1-6. They include one nucleobase uracil (1), two nucleosides uridine (2) and adenosine (3), one alkaloid indole-3-carboxylic acid (4), one mono-phenol glucoside koaburside (5), and one saponin randianin (6). The chemical structures of these phytochemicals were elucidated by physicochemical, the 1D-NMR [1H, 13C-NMR, and DEPT (Distortionless Enhancement by Polarization Transfer)], the 2D-NMR [HSQC (heteronuclear single quantum coherence), HMBC (Heteronuclear Multiple Bond Correlation), and COSY (correlation spectroscopy)] spectral, and ESI-MS (Electron Spray Ionization-Mass Spectrum) data. This is the first time that compounds 2-6 have been obtained from the genus Polyscias. In agreement with various reports, the nitrogenous compounds and triterpene saponins can be seen as characteristic metabolites of genus Polyscia
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Liang, Liming, Xiaoqi Sheng, Bowen Liu, and Zhimin Lan. "A Level Set Method with Region-Scalable Fitting Energy for Retinal Layer Segmentation in Spectral-Domain Optical Coherence Tomography Images." Journal of Medical Imaging and Health Informatics 10, no. 2 (February 1, 2020): 326–35. http://dx.doi.org/10.1166/jmihi.2020.2905.
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Retinal layer segmentation of spectral-domain optical coherence tomography images plays an important role during diagnosis and analysis of ophthalmic diseases. In this paper, a novel variational level set framework with region-scalable fitting energy is proposed for automated retinal layer segmentation in SD-OCT. To the best of our knowledge, it is the first time that level set based method succeeds in ten retinal layers segmentation. The proposed framework consists of three steps. First, an anisotropic nonlinear diffusion filter is applied for speckle noise reduction and ROI contrast enhancement. Second, Canny edge detectors are used to extract initial layers: nerve fiber layer, connecting cilia and retinal pigment epithelium. Finally, the rest retinal layers are segmented by means of level set model combined with prior knowledge of retinal thickness and morphology, for which the energy function consists of region-scalable fitting energy data term, area constraint term, regularization term and length penalty term. The proposed method was tested on 50 retinal SD-OCT B-scans from 50 normal subjects. The overall unsigned border position error is 5.92 ± 4.72 μm. The result showed that data terms with border weight terms can keep layer segmentation results in strong border while retaining its fitting capability in weak border. The proposed method achieves better segmentation result than other active contour models.
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Naniyil, Vineetha, Yijia Zhou, Guy Simmonds, Nathan Cooper, Weibin Li, and Lucia Hackermüller. "Observation of collectivity enhanced magnetoassociation of 6Li in the quantum degenerate regime." New Journal of Physics 24, no. 11 (November 1, 2022): 113005. http://dx.doi.org/10.1088/1367-2630/ac9b81.
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Abstract The association process of Feshbach molecules is well described by a Landau–Zener (LZ) transition above the Fermi temperature, such that two-body physics dominates the dynamics. However, using 6Li atoms and the associated Feshbach resonance at B r = 834.1 G, we observe an enhancement of the atom–molecule coupling as the fermionic atoms reach degeneracy, demonstrating the importance of many-body coherence not captured by the conventional LZ model. In the experiment, we apply a linear association ramp ranging from adiabatic to non-equilibrium molecule association for various temperatures. We develop a theoretical model that explains the temperature dependence of the atom–molecule coupling. Furthermore, we characterize this dependence experimentally and extract the atom–molecule coupling coefficient as a function of temperature, finding qualitative agreement between our model and experimental results. In addition, we simulate the dynamics of molecular association during a nonlinear field ramp. We find that, in the non-equilibrium regime, molecular association efficiency can be enhanced by sweeping the magnetic field cubically with time. Accurate measurement of the atom–molecule coupling coefficient is important for both theoretical and experimental studies of molecular association and many-body collective dynamics.
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Lai, E. V., B. De Marco, A. A. Zdziarski, T. M. Belloni, S. Mondal, P. Uttley, V. Grinberg, J. Wilms, and A. Różańska. "The X-ray spectral-timing contribution of the stellar wind in the hard state of Cyg X-1." Monthly Notices of the Royal Astronomical Society 512, no. 2 (March 16, 2022): 2671–85. http://dx.doi.org/10.1093/mnras/stac688.
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ABSTRACT The clumpy stellar wind from the companion star in high-mass X-ray binaries causes variable, partial absorption of the emission from the X-ray source. We studied XMM–Newton observations from a 7.22 d long monitoring campaign, in order to constrain the effects of the stellar wind on the short-time-scale X-ray spectral-timing properties of Cygnus X-1. We find these properties to change significantly in the presence of the wind. In particular, the longest sampled time-scales (corresponding to temporal frequencies of ν ∼ 0.1–1 Hz) reveal an enhancement of the fractional variability power, while on the shortest sampled time-scales (ν ∼ 1–10 Hz), the variability is suppressed. In addition, we observe a reduction (by up to a factor of ∼ 1.8) of the otherwise high coherence between soft and hard band light curves, as well as of the amplitude of the hard X-ray lags intrinsic to the X-ray continuum. The observed increase of low-frequency variability power can be explained in terms of variations of the wind column density as a consequence of motions of the intervening clumps. In this scenario (and assuming a terminal velocity of $v_{\infty }=2400\, {\rm km\ s^{-1}}$), we obtain an estimate of l ∼ 0.5–1.5 × 10−4R* for the average radial size of a clump. On the other hand, we suggest the behaviour at high frequencies to be due to scattering in an optically thicker medium, possibly formed by collision of the stellar wind with the edge of the disc.
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Wang, Dawei, Hongliu Zeng, Shiguo Wu, Weiwei Wang, Qingping Li, and Lijun Mi. "Seismic sedimentological evidence for filling process of western Central Canyon System controlled by the evolution of the Tibetan Plateau and the East Asia monsoon since the Late Miocene, South China Sea." Interpretation 6, no. 2 (May 1, 2018): SD41—SD55. http://dx.doi.org/10.1190/int-2017-0176.1.
Full textAbstract:
Three-dimensional blended data, comprised of amplitude and coherence cubes, are used to analyze the evolution of the Central Canyon System (CCS) since the Late Miocene within the western Qiongdongnan Basin (QDNB), South China Sea. The evolution of the canyon since the late Miocene includes two phases and five stages, with a dramatic change of deepwater sediment bodies from early, predominantly axial channel-levee deposits (CLDs) to late, primarily side mass-transport deposits (MTD). During the first and second stages (approximately 5.3–3.7 Ma), axial CLDs derived from the western slope of the South China Sea dominated the sediment bodies within the canyon. The last three stages (3.7 Ma to Recent) were dominated by side MTD, which originated from the northern slope of the South China Sea. Since the canyon was completely filled at 2.4 Ma, axial CLDs only reactivated in the lower strata of the most southern region of the study area. The time of formation of the CCS (approximately 11.6–8.2 Ma) is almost synchronous with the rise of the Himalayas and the first enhancement of the East Asia monsoon during the middle and late Miocene. The change of deepwater deposits within the canyon, which has varied from CLDs to MTDs since 3.7 Ma, is in phase with the further rapid uplift of the entire Tibetan Plateau and the second enhancement of the East Asia monsoon during the middle Pliocene. This evidence suggests that the formation and filling of the canyon should be controlled by the evolution of the Tibetan Plateau and the East Asia monsoon. Tectonics and the East Asia monsoon controlled the evolution of the CCS by changing erosion rates from the Tibetan Plateau, South China Block, and Indochina Peninsula, and sedimentary rates within the Yinggehai Basin and QDNB.
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Simões, M., M. M. Telo da Gama, and A. Nunes. "Stochastic fluctuations in epidemics on networks." Journal of The Royal Society Interface 5, no. 22 (October 2, 2007): 555–66. http://dx.doi.org/10.1098/rsif.2007.1206.
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The effects of demographic stochasticity on the long-term behaviour of endemic infectious diseases have been considered for long as a necessary addition to an underlying deterministic theory. The latter would explain the regular behaviour of recurrent epidemics and the former the superimposed noise of observed incidence patterns. Recently, a stochastic theory based on a mechanism of resonance with internal noise has shifted the role of stochasticity closer to the centre stage, by showing that the major dynamic patterns found in the incidence data can be explained as resonant fluctuations, whose behaviour is largely independent of the amplitude of seasonal forcing, and by contrast very sensitive to the basic epidemiological parameters. Here we elaborate on that approach, by adding an ingredient which is missing in standard epidemic models, the ‘mixing network’ through which infection may propagate. We find that spatial correlations have a major effect on the enhancement of the amplitude and the coherence of the resonant stochastic fluctuations, providing the ordered patterns of recurrent epidemics, whose period may differ significantly from that of the small oscillations around the deterministic equilibrium. We also show that the inclusion of a more realistic, time-correlated recovery profile instead of exponentially distributed infectious periods may, even in the random-mixing limit, contribute to the same effect.
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Versolato, O. O., L. W. Wansbeek, G. S. Giri, J. E. van den Berg, D. J. van der Hoek, K. Jungmann, W. L. Kruithof, et al. "Atomic parity violation in a single trapped radium ionThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010." Canadian Journal of Physics 89, no. 1 (January 2011): 65–68. http://dx.doi.org/10.1139/p10-051.
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Atomic parity violation (APV) experiments are sensitive probes of the electroweak interaction at low energy. These experiments are competitive with and complementary to high-energy collider experiments. The APV signal is strongly enhanced in heavy atoms, and it is measurable by exciting suppressed (M1, E2) transitions. The predicted enhancement factor of the APV effect in the S-D transition in Ra+ is about 50 times larger than the S-S transition in neutral Cs. However, certain spectroscopic information on Ra+, needed to constrain the required atomic many-body theory, was lacking. Using the AGOR cyclotron and the TRIμP facility at KVI in Groningen, short-lived 212–214Ra+ ions were produced and trapped. First ever excited-state laser spectroscopy was performed on the trapped ions. These measurements provide a benchmark for the atomic theory required to extract the electroweak mixing angle to sub 1% accuracy and are an important step towards an APV experiment in a single trapped Ra+ ion. A lower bound on the radiative lifetime of the 62D5/2 state was found of 232(4) ms. This experimental confirmation of the long coherence time of the meta-stable 62D5/2 state is important in light of the possibility of using a single trapped radium ion as an optical frequency standard.
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Shao, Pei-Lin, Jiunn-Der Liao, Shun-Cheng Wu, Yu-Hsing Chen, and Tak-Wah Wong. "Microplasma Treatment versus Negative Pressure Therapy for Promoting Wound Healing in Diabetic Mice." International Journal of Molecular Sciences 22, no. 19 (September 24, 2021): 10266. http://dx.doi.org/10.3390/ijms221910266.
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The delayed healing response of diabetic wounds is a major challenge for treatment. Negative pressure wound therapy (NPWT) has been widely used to treat chronic wounds. However, it usually requires a long treatment time and results in directional growth of wound healing skin tissue. We investigated whether nonthermal microplasma (MP) treatment can promote the healing of skin wounds in diabetic mice. Splint excision wounds were created on diabetic mice, and various wound healing parameters were compared among MP treatment, NPWT, and control groups. Quantitative analysis of the re-epithelialization percentage by detecting Ki67 and DSG1 expression in the extending epidermal tongue (EET) of the wound area and the epidermal proliferation index (EPI) was subsequently performed. Both treatments promoted wound healing by enhancing wound closure kinetics and wound bed blood flow; this was confirmed through histological analysis and optical coherence tomography. Both treatments also increased Ki67 and DSG1 expression in the EET of the wound area and the EPI to enhance re-epithelialization. Increased Smad2/3/4 mRNA expression was observed in the epidermis layer of wounds, particularly after MP treatment. The results suggest that the Smad-dependent transforming growth factor β signaling contributes to the enhancement of re-epithelialization after MP treatment with an appropriate exposure time. Overall, a short-term MP treatment (applied for 30 s twice a day) demonstrated comparable or better efficacy to conventional NPWT (applied for 4 h once a day) in promoting wound healing in diabetic mice. Thus, MP treatment exhibits promise for treating diabetic wounds clinically.
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Bauer, Alexander, Benjamin Schwarz, and Dirk Gajewski. "Utilizing diffractions in wavefront tomography." GEOPHYSICS 82, no. 2 (March 1, 2017): R65—R73. http://dx.doi.org/10.1190/geo2016-0396.1.
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Wavefront tomography is known to be an efficient and stable approach for velocity inversion that does not require accurate starting models and does not interact directly with the prestack data. Instead, the original data are transformed to physically meaningful wavefront attribute fields. These can be automatically estimated using local-coherence analysis by means of the common-reflection-surface (CRS) stack, which has been shown to be a powerful tool for data analysis and enhancement. In addition, the zero-offset wavefront attributes acquired during the CRS stack can be used for sophisticated subsequent processes such as wavefield characterization and separation. Whereas in previous works, wavefront tomography has been applied mainly to reflection data, resulting in smooth velocity models suitable for migration of targets with moderately complex overburden, we have emphasized using the diffracted contributions in the data for velocity inversion. By means of simple synthetic examples, we reveal the potential of diffractions for velocity inversion. On industrial field data, we suggest a joint inversion based on reflected and diffracted contributions of the measured wavefield, which confirms the general finding that diffraction-based wavefront tomography can help to increase the resolution of the velocity models. Concluding our work, we compare the quality of a reverse time migrated result using the estimated velocity model with the result based on the inversion of reflections, which reveals an improved imaging potential for a complex salt geometry.
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Korner, Anthony. "The embodiment of language." Language, Context and Text 4, no. 1 (April 6, 2022): 26–60. http://dx.doi.org/10.1075/langct.21010.kor.
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Abstract In this paper an understanding of psychotherapeutic conversation is outlined emphasising whole-body functioning. The underpinning of conversation by both Central and Autonomic Nervous Systems (CNS & ANS) and evolutionary developments that support social engagement and language are considered. An idea will be taken up that for psychotherapy, language needs to be understood within each patient as more than meets the eye, rather than less, providing a potential for exchanges in the therapeutic conversation that enhance the growth of self for each individual. The notion of culminative patterns of communicative interaction speaks to this growth and the enhancement of a sense of meaning in personal contexts. This goes beyond an analytic approach, implying synthesis, integration and growing coherence over time. Human development is towards social engagement, building upon a capacity for relations that are rewarding to the parties involved (Meares 2016). The problem of responding to embodied communication in psychotherapy is considered in relation to moments of meeting, seen as mutative in therapy. Each person is an embodied text with potential for elaboration, re-shaping and discovery. Clinical illustrations are provided, demonstrating a linguistic model of therapeutic growth and an experimental method that provides a window onto the exchange characteristics of language. To close, the problem of systematising embodiment and its relation to the conversation is considered, along with the implications for therapy and future research, integrating linguistics and interactive functional measures of the body.
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Sülsen, Valeria P., Fernanda M. Frank, Silvia I. Cazorla, Claudia A. Anesini, Emilio L. Malchiodi, Blanca Freixa, Roser Vila, Liliana V. Muschietti, and Virginia S. Martino. "Trypanocidal and Leishmanicidal Activities of Sesquiterpene Lactones from Ambrosia tenuifolia Sprengel (Asteraceae)." Antimicrobial Agents and Chemotherapy 52, no. 7 (April 28, 2008): 2415–19. http://dx.doi.org/10.1128/aac.01630-07.
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ABSTRACT Bioassay-guided fractionation of the organic extract of Ambrosia tenuifolia Sprengel (Asteraceae) led to the isolation of two bioactive sesquiterpene lactones with significant trypanocidal and leishmanicidal activities. By spectroscopic methods (1H- and 13C-nuclear magnetic resonance, distortionless enhancement by polarization transfer, correlated spectroscopy, heteronuclear multiple-quantum coherence, electron impact-mass spectrometry, and infrared spectroscopy), these compounds were identified as psilostachyin and peruvin. Both compounds showed a marked in vitro trypanocidal activity against Trypanosoma cruzi epimastigotes with 50% inhibitory concentration (IC50) values of less than 2 μg/ml. Psilostachyin exerted a significant in vitro activity against the trypomastigote forms of T. cruzi (IC50, 0.76 μg/ml) and was selected for in vivo testing. Psilostachyin-treated mice had a survival of 100% and lower parasitemia values than control mice. Both compounds were also tested on Leishmania sp. promastigotes: psilostachyin (IC50, 0.12 μg/ml) and peruvin (IC50, 0.39 μg/ml) exerted significant leishmanicidal activities. This is the first time that the trypanocidal and leishmanicidal activities of these compounds have been reported. The selectivity index (SI) was employed to evaluate the cytotoxic effect of lactones on T lymphocytes. Although the SIs of both compounds were high for T. cruzi epimastigotes, psilostachyin was more selective against trypomastigotes (SI, 33.8) while peruvin showed no specificity for this parasite. Both compounds presented high selectivity for Leishmania spp. The results shown herein suggest that psilostachyin and peruvin could be considered potential candidates for the development of new antiprotozoal agents against Chagas' disease and leishmaniasis.
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Perrodin, Catherine, Christoph Kayser, Nikos K. Logothetis, and Christopher I. Petkov. "Natural asynchronies in audiovisual communication signals regulate neuronal multisensory interactions in voice-sensitive cortex." Proceedings of the National Academy of Sciences 112, no. 1 (December 22, 2014): 273–78. http://dx.doi.org/10.1073/pnas.1412817112.
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When social animals communicate, the onset of informative content in one modality varies considerably relative to the other, such as when visual orofacial movements precede a vocalization. These naturally occurring asynchronies do not disrupt intelligibility or perceptual coherence. However, they occur on time scales where they likely affect integrative neuronal activity in ways that have remained unclear, especially for hierarchically downstream regions in which neurons exhibit temporally imprecise but highly selective responses to communication signals. To address this, we exploited naturally occurring face- and voice-onset asynchronies in primate vocalizations. Using these as stimuli we recorded cortical oscillations and neuronal spiking responses from functional MRI (fMRI)-localized voice-sensitive cortex in the anterior temporal lobe of macaques. We show that the onset of the visual face stimulus resets the phase of low-frequency oscillations, and that the face–voice asynchrony affects the prominence of two key types of neuronal multisensory responses: enhancement or suppression. Our findings show a three-way association between temporal delays in audiovisual communication signals, phase-resetting of ongoing oscillations, and the sign of multisensory responses. The results reveal how natural onset asynchronies in cross-sensory inputs regulate network oscillations and neuronal excitability in the voice-sensitive cortex of macaques, a suggested animal model for human voice areas. These findings also advance predictions on the impact of multisensory input on neuronal processes in face areas and other brain regions.
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London, Frédéric, Hélène Zéphir, Nawal Hadhoum, Julien Lannoy, Patrick Vermersch, Jean-Pierre Pruvo, Jérôme Hodel, Xavier Leclerc, and Olivier Outteryck. "Optic nerve double inversion recovery hypersignal in patients with clinically isolated syndrome is associated with asymptomatic gadolinium-enhanced lesion." Multiple Sclerosis Journal 25, no. 14 (December 3, 2018): 1888–95. http://dx.doi.org/10.1177/1352458518815797.
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Background: Optic nerve involvement is not considered in dissemination in space (DIS) or time (DIT) of multiple sclerosis (MS) lesions. Objectives: To evaluate frequency of optic nerve involvement using three-dimensional (3D)-double inversion recovery (DIR) sequence in clinically isolated syndrome (CIS) and to measure its relationship with DIS and DIT (2010 and 2017 McDonald criteria). Methods: From November 2013 to August 2016, 57 CIS patients underwent 3T-magnetic resonance imaging (3T-MRI) including 3D-DIR sequence and optical coherence tomography (OCT) at 3 months after CIS. We assessed signal abnormalities of the optic nerves on DIR sequence and collected data for DIS and DIT criteria according to 2010 and 2017 McDonald criteria. Results: Among the 57 recruited patients, the presence of ⩾1 DIR hypersignal in optic nerve was observed in 36 (63%; 48 optic nerves) including asymptomatic hypersignal in 22 (38.5%; 25 optic nerves). Optic nerve involvement was significantly associated with DIT ( p = 0.006) and MS according to 2010 criteria ( p = 0.01) but was not significantly associated with presence of DIS criteria according to 2010 and 2017 McDonald criteria. We identified a significant ( p < 0.001) temporal peripapillary retinal nerve fiber layer thinning on eyes with optic nerve involvement versus healthy controls. Conclusions: Optic nerve involvement is very frequent at the earliest clinical stage of MS. It is associated with the presence of asymptomatic gadolinium-enhancement and retinal axonal loss and may reflect the inflammatory disease activity level.
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Wang, Mengyuan, Yuye Ling, Zhenxing Dong, Xinwen Yao, Yu Gan, Chuanqing Zhou, and Yikai Su. "GPU-accelerated iterative method for FD-OCT image reconstruction with an image-level cross-domain regularizer." Optics Express 31, no. 2 (January 5, 2023): 1813. http://dx.doi.org/10.1364/oe.478970.
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The image reconstruction for Fourier-domain optical coherence tomography (FD-OCT) could be achieved by iterative methods, which offer a more accurate estimation than the traditional inverse discrete Fourier transform (IDFT) reconstruction. However, the existing iterative methods are mostly A-line-based and are developed on CPU, which causes slow reconstruction. Besides, A-line-based reconstruction makes the iterative methods incompatible with most existing image-level image processing techniques. In this paper, we proposed an iterative method that enables B-scan-based OCT image reconstruction, which has three major advantages: (1) Large-scale parallelism of the OCT dataset is achieved by using GPU acceleration. (2) A novel image-level cross-domain regularizer was developed, such that the image processing could be performed simultaneously during the image reconstruction; an enhanced image could be directly generated from the OCT interferogram. (3) The scalability of the proposed method was demonstrated for 3D OCT image reconstruction. Compared with the state-of-the-art (SOTA) iterative approaches, the proposed method achieves higher image quality with reduced computational time by orders of magnitude. To further show the image enhancement ability, a comparison was conducted between the proposed method and the conventional workflow, in which an IDFT reconstructed OCT image is later processed by a total variation-regularized denoising algorithm. The proposed method can achieve a better performance evaluated by metrics such as signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), while the speed is improved by more than 30 times. Real-time image reconstruction at more than 20 B-scans per second was realized with a frame size of 4096 (axial) × 1000 (lateral), which showcases the great potential of the proposed method in real-world applications.
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Stąsiek, Jan, Adam Stąsiek, and Marek Szkodo. "Modeling of Passive and Forced Convection Heat Transfer in Channels with Rib Turbulators." Energies 14, no. 21 (October 28, 2021): 7059. http://dx.doi.org/10.3390/en14217059.
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The main goal of the research presented in this paper was the experimental and numerical analysis of heat enhancement and aerodynamic phenomena during air flow in a channel equipped with flow turbulators in the form of properly configured ribs. The use of ribs intensifies the heat transfer and at the same time increases not only the flow resistance but also the energy costs. Therefore, designing modern heat exchangers with optimal thermal and flow parameters requires the knowledge of the theory of heat exchangers as well as measurement methods and numerical calculations. Bearing in mind the above, the liquid crystal techniques (LCT), particle image velocimetry (PIV) and digital image processing (DIP) for temperature, velocity, friction factor and heat transfer coefficient measurements are presented herein. These three optical tools (using desktop computers) create an extremely powerful and advanced measuring technique that has not been available anywhere before. Brief histories of these measurement methods and techniques are discussed and some examples are presented. In order to assess and select the value of the measurement technique, local and average distributions of Nusselt numbers (in the measurement section) obtained by the transit analysis method on the inter-rib regions of a plate coated by thermochromics liquid crystal and heated by air as an alternative to the steady-state analysis. In the parallel, numerical calculation was performed with the use of the ANSYS Fluent software code and supported by laser anemometry-computed turbulence intensity of air flow. Comparison of the Nusselt number distributions was determined by three methods, i.e., steady state, the transient method and CFD simulation. Up to three-fold enhancement of the local heat transfer capability was observed. Failure to take into account the surface of the ribs in heat transfer causes differences in the obtained results of the Nusselt number depending on the method used. Apart from the heat transfer data, the pressure drop in the form of friction factors is also presented. On the basis of the conducted research, it can be stated that both qualitative and quantitative coherence was obtained between the experimental and computational studies.
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Schubert, Tina, Steffen Rausch, Omar Fahmy, Georgios Gakis, and Arnulf Stenzl. "Optical improvements in the diagnosis of bladder cancer: implications for clinical practice." Therapeutic Advances in Urology 9, no. 11 (September 4, 2017): 251–60. http://dx.doi.org/10.1177/1756287217720401.
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Background For over 100 years white-light cystoscopy has remained the gold-standard technique for the detection of bladder cancer (BCa). Some limitations in the detection of flat lesions (CIS), the differentiation between inflammation and malignancy, the inaccurate determination of the tumor margin status as well as the tumor depth, have led to a variety of technological improvements. The aim of this review is to evaluate the impact of these improvements in the diagnosis of BCa and their effectiveness in clinical practice. Methods A systematic literature search was conducted according to the PRISMA statement to identify studies reporting on imaging modalities in the diagnosis of NMIBC between 2000 and 2017. A two-stage selection process was utilized to determine eligible studies. A total of 74 studies were considered for final analysis. Results Optical imaging technologies have emerged as an adjunct to white-light cystoscopy and can be classified according to their scope as macroscopic, microscopic and molecular. Macroscopic techniques including photodynamic diagnosis (PDD), narrow-band imaging (NBI) and the Storz Professional Image Enhancement System (IMAGE1 S, formerly known as SPIES) are similar to white-light cystoscopy, but are superior in the detection of bladder tumors by means of contrast enhancement. Especially the detection rate of very mute lesions in the bladder mucosa (CIS) could be significantly increased by the use of these methods. Microscopic imaging techniques like confocal laser endomicroscopy and optical coherence tomography permit a real-time high-resolution assessment of the bladder mucosa at a cellular and sub-cellular level with spatial resolutions similar to histology, enabling the surgeon to perform an ‘optical biopsy’. Molecular techniques are based on the combination of optical imaging technologies with fluorescence labeling of cancer-specific molecular agents like antibodies. This labeling is intended to favor an optical distinction between benign and malignant tissue. Conclusions Optical improvements of the standard white-light cystoscopy have proven their benefit in the detection of BCa and have found their way into clinical practice. Especially the combination of macroscopic and microscopic techniques may improve diagnostic accuracy. Nevertheless, HAL-PDD guided cystoscopy is the only approach approved for routine use in the diagnosis of BCa by most urological associations in the EU and USA to date.
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Garway-Heath, David F., Haogang Zhu, Qian Cheng, Katy Morgan, Chris Frost, David P. Crabb, Tuan-Anh Ho, and Yannis Agiomyrgiannakis. "Combining optical coherence tomography with visual field data to rapidly detect disease progression in glaucoma: a diagnostic accuracy study." Health Technology Assessment 22, no. 4 (January 2018): 1–106. http://dx.doi.org/10.3310/hta22040.
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Background Progressive optic nerve damage in glaucoma results in vision loss, quantifiable with visual field (VF) testing. VF measurements are, however, highly variable, making identification of worsening vision (‘progression’) challenging. Glaucomatous optic nerve damage can also be measured with imaging techniques such as optical coherence tomography (OCT). Objective To compare statistical methods that combine VF and OCT data with VF-only methods to establish whether or not these allow (1) more rapid identification of glaucoma progression and (2) shorter or smaller clinical trials. Design Method ‘hit rate’ (related to sensitivity) was evaluated in subsets of the United Kingdom Glaucoma Treatment Study (UKGTS) and specificity was evaluated in 72 stable glaucoma patients who had 11 VF and OCT tests within 3 months (the RAPID data set). The reference progression detection method was based on Guided Progression Analysis™ (GPA) Software (Carl Zeiss Meditec Inc., Dublin, CA, USA). Index methods were based on previously described approaches [Analysis with Non-Stationary Weibull Error Regression and Spatial enhancement (ANSWERS), Permutation analyses Of Pointwise Linear Regression (PoPLR) and structure-guided ANSWERS (sANSWERS)] or newly developed methods based on Permutation Test (PERM), multivariate hierarchical models with multiple imputation for censored values (MaHMIC) and multivariate generalised estimating equations with multiple imputation for censored values (MaGIC). Setting Ten university and general ophthalmology units (UKGTS) and a single university ophthalmology unit (RAPID). Participants UKGTS participants were newly diagnosed glaucoma patients randomised to intraocular pressure-lowering drops or placebo. RAPID participants had glaucomatous VF loss, were on treatment and were clinically stable. Interventions 24-2 VF tests with the Humphrey Field Analyzer and optic nerve imaging with time-domain (TD) Stratus OCT™ (Carl Zeiss Meditec Inc., Dublin, CA, USA). Main outcome measures Criterion hit rate and specificity, time to progression, future VF prediction error, proportion progressing in UKGTS treatment groups, hazard ratios (HRs) and study sample size. Results Criterion specificity was 95% for all tests; the hit rate was 22.2% for GPA, 41.6% for PoPLR, 53.8% for ANSWERS and 61.3% for sANSWERS (all comparisons p ≤ 0.042). Mean survival time (weeks) was 93.6 for GPA, 82.5 for PoPLR, 72.0 for ANSWERS and 69.1 for sANSWERS. The median prediction errors (decibels) when the initial trend was used to predict the final VF were 3.8 (5th to 95th percentile 1.7 to 7.6) for PoPLR, 3.0 (5th to 95th percentile 1.5 to 5.7) for ANSWERS and 2.3 (5th to 95th percentile 1.3 to 4.5) for sANSWERS. HRs were 0.57 [95% confidence interval (CI) 0.34 to 0.90; p = 0.016] for GPA, 0.59 (95% CI 0.42 to 0.83; p = 0.002) for PoPLR, 0.76 (95% CI 0.56 to 1.02; p = 0.065) for ANSWERS and 0.70 (95% CI 0.53 to 0.93; p = 0.012) for sANSWERS. Sample size estimates were not reduced using methods including OCT data. PERM hit rates were between 8.3% and 17.4%. Treatment effects were non-significant in MaHMIC and MaGIC analyses; statistical significance was altered little by incorporating imaging. Limitations TD OCT is less precise than current imaging technology; current OCT technology would likely perform better. The size of the RAPID data set limited the precision of criterion specificity estimates. Conclusions The sANSWERS method combining VF and OCT data had a higher hit rate and identified progression more quickly than the reference and other VF-only methods, and produced more accurate estimates of the progression rate, but did not increase treatment effect statistical significance. Similar studies with current OCT technology need to be undertaken and the statistical methods need refinement. Trial registration Current Controlled Trials ISRCTN96423140. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 4. See the NIHR Journals Library website for further project information. Data analysed in the study were from the UKGTS. Funding for the UKGTS was provided through an unrestricted investigator-initiated research grant from Pfizer Inc. (New York, NY, USA), with supplementary funding from the NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK. Imaging equipment loans were made by Heidelberg Engineering, Carl Zeiss Meditec and Optovue (Fremont, CA, USA). Pfizer, Heidelberg Engineering, Carl Zeiss Meditec and Optovue had no input into the design, conduct, analysis or reporting of any of the UKGTS findings or this work. The sponsor for both the UKGTS and RAPID data collection was Moorfields Eye Hospital NHS Foundation Trust. David F Garway-Heath, Tuan-Anh Ho and Haogang Zhu are partly funded by the NIHR Biomedical Research Centre based at Moorfields Eye Hospital and UCL Institute of Ophthalmology. David F Garway-Heath’s chair at University College London (UCL) is supported by funding from the International Glaucoma Association.
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Lin, Yi, Xinran Fan, Yueqi Chen, Hao Zhang, Fei Chen, Hui Zhang, Hongwei Ding, and Yang Zhang. "Neurocognitive Dynamics of Prosodic Salience over Semantics during Explicit and Implicit Processing of Basic Emotions in Spoken Words." Brain Sciences 12, no. 12 (December 12, 2022): 1706. http://dx.doi.org/10.3390/brainsci12121706.
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How language mediates emotional perception and experience is poorly understood. The present event-related potential (ERP) study examined the explicit and implicit processing of emotional speech to differentiate the relative influences of communication channel, emotion category and task type in the prosodic salience effect. Thirty participants (15 women) were presented with spoken words denoting happiness, sadness and neutrality in either the prosodic or semantic channel. They were asked to judge the emotional content (explicit task) and speakers’ gender (implicit task) of the stimuli. Results indicated that emotional prosody (relative to semantics) triggered larger N100, P200 and N400 amplitudes with greater delta, theta and alpha inter-trial phase coherence (ITPC) and event-related spectral perturbation (ERSP) values in the corresponding early time windows, and continued to produce larger LPC amplitudes and faster responses during late stages of higher-order cognitive processing. The relative salience of prosodic and semantics was modulated by emotion and task, though such modulatory effects varied across different processing stages. The prosodic salience effect was reduced for sadness processing and in the implicit task during early auditory processing and decision-making but reduced for happiness processing in the explicit task during conscious emotion processing. Additionally, across-trial synchronization of delta, theta and alpha bands predicted the ERP components with higher ITPC and ERSP values significantly associated with stronger N100, P200, N400 and LPC enhancement. These findings reveal the neurocognitive dynamics of emotional speech processing with prosodic salience tied to stage-dependent emotion- and task-specific effects, which can reveal insights into understanding language and emotion processing from cross-linguistic/cultural and clinical perspectives.
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Khan, Nawazish A., and M. Usman Muzaffar. "Decoupling of the CuO2 plane and superconductivity in Cu0.5Tl0.5Ba2(Ca2−ySry)Cu3O10−δ(y = 0–0.4) samples." International Journal of Modern Physics B 30, no. 17 (June 30, 2016): 1650097. http://dx.doi.org/10.1142/s0217979216500971.
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[Formula: see text]–[Formula: see text] samples have been synthesized at normal pressure at 860[Formula: see text]C. The main objectives of these experiments to study the role of inter-plane decoupling in suppressing the superconductivity of high temperature superconductors (HTSC). These samples have shown orthorhombic crystal structure and the [Formula: see text]-axis length increases with increased Sr-doping. All the samples have shown metallic variations of resistivity [Formula: see text] from room temperature down to the onset of superconductivity. The magnitude of the superconductivity is suppressed and the apical oxygen modes are hardened with Sr-doping. These studies have shown that Sr-doping promotes decoupling of conducting [Formula: see text] planes which suppress the superconducting properties of final compound. The excess conductivity analyses have shown increases in the width of two-dimensional (2D) Lawrence–Doniach (LD) regime with Sr-doping. The coherence length along the [Formula: see text]-axis [Formula: see text], the inter-layer coupling [Formula: see text], the phase relaxation time of the carriers [Formula: see text] and the Fermi velocity [Formula: see text] of superconductor carriers is suppressed. The underlying reason for the suppression of superconductor properties is the decrease in the density of carriers in the superconductor planes. However, the values of [Formula: see text], [Formula: see text] and [Formula: see text] have been found to increase with the increased Sr-doping, which is suggested to be originating from the enhancement in the flux pinning character which is induced by Sr-doping. The values of magnetic field penetration depth [Formula: see text] and the Ginzburg–Landau (GL) parameter [Formula: see text] decrease with Sr-doping and it is also suggested to be originating from the increase of flux pinning character of the samples with Sr-doping.