scholarly journals A compact lightweight multipurpose ground-penetrating radar for glaciological applications

2011 ◽  
Vol 57 (206) ◽  
pp. 1113-1118 ◽  
Author(s):  
E.V. Vasilenko ◽  
F. Machío ◽  
J.J. Lapazaran ◽  
F.J. Navarro ◽  
K. Frolovskiy
Keyword(s):  
Dynamic Range ◽  
Time Window ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Peak Voltage ◽  
Recording Time ◽  
Single Person ◽  
Radio Echo Sounding ◽  
Power Peak ◽  
Ground Penetrating

AbstractWe describe a compact lightweight impulse radar for radio-echo sounding of subsurface structures designed specifically for glaciological applications. The radar operates at frequencies between 10 and 75 MHz. Its main advantages are that it has a high signal-to-noise ratio and a corresponding wide dynamic range of 132 dB due mainly to its ability to perform real-time stacking (up to 4096 traces) as well as to the high transmitted power (peak voltage 2800 V). The maximum recording time window, 40 μs at 100 MHz sampling frequency, results in possible radar returns from as deep as 3300 m. It is a versatile radar, suitable for different geophysical measurements (common-offset profiling, common midpoint, transillumination, etc.) and for different profiling set-ups, such as a snowmobile and sledge convoy or carried in a backpack and operated by a single person. Its low power consumption (6.6 W for the transmitter and 7.5 W for the receiver) allows the system to operate under battery power for >7 hours with a total weight of <9 kg for all equipment, antennas and batteries.

scholarly journals Ab initiostructure determination of nanocrystals of organic pharmaceutical compounds by electron diffraction at room temperature using a Timepix quantum area direct electron detector

2016 ◽  
Vol 72 (2) ◽  
pp. 236-242 ◽  
Author(s):  
E. van Genderen ◽  
M. T. B. Clabbers ◽  
P. P. Das ◽  
A. Stewart ◽  
I. Nederlof ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Direct Methods ◽  
Liquid Nitrogen Temperature ◽  
High Dynamic Range ◽  
Electron Diffraction Data ◽  
High Signal

Until recently, structure determination by transmission electron microscopy of beam-sensitive three-dimensional nanocrystals required electron diffraction tomography data collection at liquid-nitrogen temperature, in order to reduce radiation damage. Here it is shown that the novel Timepix detector combines a high dynamic range with a very high signal-to-noise ratio and single-electron sensitivity, enablingab initiophasing of beam-sensitive organic compounds. Low-dose electron diffraction data (∼0.013 e− Å−2 s−1) were collected at room temperature with the rotation method. It was ascertained that the data were of sufficient quality for structure solution using direct methods using software developed for X-ray crystallography (XDS,SHELX) and for electron crystallography (ADT3D/PETS,SIR2014).

scholarly journals Methods for Voltage-Sensitive Dye Imaging of Rat Cortical Activity With High Signal-to-Noise Ratio

2007 ◽  
Vol 98 (1) ◽  
pp. 502-512 ◽  
Author(s):  
Michael T. Lippert ◽  
Kentaroh Takagaki ◽  
Weifeng Xu ◽  
Xiaoying Huang ◽  
Jian-Young Wu
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Field Potential ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
High Signal ◽  
Blue Dye ◽  
Voltage Sensitive Dye ◽  
Imaging Device

We describe methods to achieve high sensitivity in voltage-sensitive dye (VSD) imaging from rat barrel and visual cortices in vivo with the use of a blue dye RH1691 and a high dynamic range imaging device (photodiode array). With an improved staining protocol and an off-line procedure to remove pulsation artifact, the sensitivity of VSD recording is comparable with that of local field potential recording from the same location. With this sensitivity, one can record from ∼500 individual detectors, each covering an area of cortical tissue 160 μm in diameter (total imaging field ∼4 mm in diameter) and a temporal resolution of 1,600 frames/s, without multiple-trial averaging. We can record 80–100 trials of intermittent 10-s trials from each imaging field before the VSD signal reduces to one half of its initial amplitude because of bleaching and wash-out. Taken together, the methods described in this report provide a useful tool for visualizing evoked and spontaneous waves from rodent cortex.

Assisted traveltime picking of crosshole GPR data

Geophysics ◽  
2009 ◽  
Vol 74 (4) ◽  
pp. J35-J48 ◽  
Author(s):  
Bernard Giroux ◽  
Abderrezak Bouchedda ◽  
Michel Chouteau
Keyword(s):  
Time Window ◽  
Signal To Noise Ratio ◽  
Real Data ◽  
Information Criterion ◽  
High Signal ◽  
Data Sets ◽  
Signal To Noise ◽  
Arrival Times ◽  
Common Time ◽  
Waveform Similarity

We introduce two new traveltime picking schemes developed specifically for crosshole ground-penetrating radar (GPR) applications. The main objective is to automate, at least partially, the traveltime picking procedure and to provide first-arrival times that are closer in quality to those of manual picking approaches. The first scheme is an adaptation of a method based on cross-correlation of radar traces collated in gathers according to their associated transmitter-receiver angle. A detector is added to isolate the first cycle of the radar wave and to suppress secon-dary arrivals that might be mistaken for first arrivals. To improve the accuracy of the arrival times obtained from the crosscorrelation lags, a time-rescaling scheme is implemented to resize the radar wavelets to a common time-window length. The second method is based on the Akaike information criterion(AIC) and continuous wavelet transform (CWT). It is not tied to the restrictive criterion of waveform similarity that underlies crosscorrelation approaches, which is not guaranteed for traces sorted in common ray-angle gathers. It has the advantage of being automated fully. Performances of the new algorithms are tested with synthetic and real data. In all tests, the approach that adds first-cycle isolation to the original crosscorrelation scheme improves the results. In contrast, the time-rescaling approach brings limited benefits, except when strong dispersion is present in the data. In addition, the performance of crosscorrelation picking schemes degrades for data sets with disparate waveforms despite the high signal-to-noise ratio of the data. In general, the AIC-CWT approach is more versatile and performs well on all data sets. Only with data showing low signal-to-noise ratios is the AIC-CWT superseded by the modified crosscorrelation picker.

scholarly journals Special features of radio pulse spectral density analysis

2020 ◽  
Vol 27 (4) ◽  
pp. e103
Author(s):  
Andrew Chubykalo ◽  
Augusto Espinoza ◽  
Victor Kuligin
Keyword(s):  
Spectral Density ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Radio Pulse ◽  
High Signal ◽  
Large Dynamic Range ◽  
High Duty Cycle ◽  
Radio Signals ◽  
Large Period ◽  
Density Analysis

The spectrum analysis of the periodic sequence radio pulses is often described in textbooks. However, if this method is applied to short radio pulses with a large period between them, then large errors occur. In this article, we described a new method of pulse gating. This method allows us to measure the spectral density of radio signals with high duty cycle. The main advantages of our method are a high signal-to-noise ratio, a large dynamic range of measurements, and a higher accuracy of spectral density measurements.

Extension of xMAP Food Allergen Detection Assay to Include Sesame

2019 ◽  
Vol 83 (1) ◽  
pp. 129-135 ◽  
Author(s):  
CHUNG Y. CHO ◽  
KATHERINE O. IVENS ◽  
WILLIAM L. NOWATZKE ◽  
JASON ROBOTHAM ◽  
MANSOUR SAMADPOUR ◽  
...  
Keyword(s):  
Food Allergen ◽  
Canola Oil ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Sesame Oil ◽  
High Signal ◽  
North American Population ◽  
Detection Assay ◽  
Allergen Detection ◽  
Limit Of Quantitation

ABSTRACT An estimated 0.1 to 0.2% of the North American population is allergic to sesame, and deaths due to anaphylactic shock have been reported. Detecting and quantifying sesame in various food samples is critical to safeguard the allergic population by ensuring accurate ingredient labeling. Because of the modular nature of the xMAP Food Allergen Detection Assay (FADA), it was possible through method extension to add sesame as a validated additional analyte. Because raw and toasted sesame are both commonly used and the two display significantly different antigenicity, three antibodies, one monoclonal and two polyclonal, were conjugated to bead sets to ensure reliable detection. The modified xMAP FADA successfully detected sesame incurred or spiked in baked muffins, spice mix, canola oil, and in both raw and toasted sesame oils with limit of quantitation values ≤ 1.3 ppm of sesame. Canola oil, sesame oil, toasted sesame oil, and olive oil inhibited sesame detection, as did the detection of sesame incurred in foods containing oil (e.g., hummus). Despite this inhibition, the xMAP FADA was still able to reliably detect sesame at levels throughout the dynamic range of the assay (22 to 750 ng of protein per mL) in all the foods examined. Further, the high signal-to-noise ratio of the lowest calibration standard and preliminary studies conjugating the antibodies at higher concentrations indicate an ability to increase the sensitivity of the assay should the need arise. HIGHLIGHTS

scholarly journals High sensitivity fluorescence up-conversion spectroscopy of 3MLCT emission of metal-organic complexes

2019 ◽  
Vol 205 ◽  
pp. 09009 ◽  
Author(s):  
Li Liu ◽  
Damianos Agathangelou ◽  
Thomas Roland ◽  
Olivier Crégut ◽  
Thibaud Duchanois ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Emission Spectra ◽  
High Sensitivity ◽  
High Signal ◽  
Triplet States ◽  
Organic Complexes ◽  
Metal Organic ◽  
Set Up ◽  
Weak Luminescence

We demonstrate the implementation of a broadband fluorescence up-conversion set-up with high signal-to-noise ratio and dynamic range allowing for the detection of weak luminescence from triplet states in Fe(II) NHC complexes. Based on the experimentally determined radiative rates and the emission spectra, these states have dominant MLCT character.

scholarly journals A Homogeneous, Nonradioactive High-Throughput Fluorogenic Protein Phosphatase Assay

2004 ◽  
Vol 9 (3) ◽  
pp. 223-231 ◽  
Author(s):  
Kevin Kupcho ◽  
Kevin Hsiao ◽  
Bob Bulleit ◽  
Said A. Goueli
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Protein Phosphatases ◽  
High Signal ◽  
Cellular Regulation ◽  
Peptide Substrates ◽  
Cellular Processes ◽  
Low Concentrations ◽  
Critical Components ◽  
Phosphatase Assay

Protein phosphatases are critical components in cellular regulation; they do not only act as antioncogenes by antagonizing protein kinases, but they also play a positive regulatory role in a variety of cellular processes that require dephosphorylation. Thus, assessing the function of these enzymes necessitates the need for a robust, sensitive assay that accurately measures their activities. The authors present a novel, homogeneous, and nonradioactive assay to measure the enzyme activity of low concentrations of several protein phosphatases (phosphoserine/phosphothreonine phosphatases and phosphotyrosine phosphatases). The assay is based on the use of fluorogenic peptide substrates (rhodamine 110, bis-phosphopeptide amide) that do not fluoresce in their conjugated form, which is resistant to cleavage by aminopeptidases. However, upon dephosphorylation by the phosphatase of interest, the peptides become cleavable by the protease and release the highly fluorescent-free rhodamine 110. The assay is rapid, can be completed in less than 2 h, and can be carried out in multiwell plate formats such as 96-, 384-, and 1536-well plates. The assay has an excellent dynamic range, high signal-to-noise ratio, and a Z′ of more than 0.8, and it is easily adapted to a robotic system for drug discovery programs targeting protein phosphatases.

scholarly journals Genetically Encoded Fluorescent Indicators for Imaging Brain Chemistry

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 116
Author(s):  
Xiaoke Bi ◽  
Connor Beck ◽  
Yiyang Gong
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Spatial Scales ◽  
High Signal ◽  
Spatiotemporal Resolution ◽  
Brain Chemistry ◽  
Fluorescent Indicators ◽  
Recent Developments

Genetically encoded fluorescent indicators, combined with optical imaging, enable the detection of physiologically or behaviorally relevant neural activity with high spatiotemporal resolution. Recent developments in protein engineering and screening strategies have improved the dynamic range, kinetics, and spectral properties of genetically encoded fluorescence indicators of brain chemistry. Such indicators have detected neurotransmitter and calcium dynamics with high signal-to-noise ratio at multiple temporal and spatial scales in vitro and in vivo. This review summarizes the current trends in these genetically encoded fluorescent indicators of neurotransmitters and calcium, focusing on their key metrics and in vivo applications.

scholarly journals Real-time decoding of 5 finger movements from 2 EMG channels for mixed reality human-computer interaction

2021 ◽  
Author(s):  
Eric James McDermott ◽  
Thimm Zwiener ◽  
Ulf Ziemann ◽  
Christoph Zrenner
Keyword(s):  
Human Computer Interaction ◽  
Real Time ◽  
Mixed Reality ◽  
Time Window ◽  
Signal To Noise Ratio ◽  
Flexor Digitorum Profundus ◽  
High Signal ◽  
K Nearest Neighbors ◽  
User Intent ◽  
Computer Interaction

The search for optimized forms of human-computer interaction (HCI) has intensified alongside the growing potential for the combination of biosignals with virtual reality (VR) and augmented reality (AR) to enable the next generation of personal computing. At the core, this requires decoding the user's biosignals into digital commands. Electromyography (EMG) is a biosensor of particular interest due to the ease of data collection, the relatively high signal-to-noise-ratio, its non-invasiveness, and the ability to interpret the signal as being generated by (intentional) muscle activity. Here, we investigate the potential of using data taken from a simple 2-channel EMG setup to differentiate 5 distinct movements. In particular, EMG was recorded from two bipolar sensors over small hand muscles (extensor digitorum, flexor digitorum profundus) while a subject performed 50 trials of dorsal extension and return for each of the five digits. The maximum and the mean data values across the trial were determined for each channel and used as features. A k-nearest neighbors (kNN) classification was performed and overall 5-class classification accuracy reached 94% when using the full trial's time window, while simulated real-time classification reached 90.4% accuracy when using the constructed kNN model (k=3) with a 280ms sliding window. Additionally, unsupervised learning was performed and a homogeneity of 85% was achieved. This study demonstrates that reliable decoding of different natural movements is possible with fewer than one channel per class, even without taking into account temporal features of the signal. The technical feasibility of this approach in a real-time setting was validated by sending real-time EMG data to a custom Unity3D VR application through a Lab Streaming Layer to control a user interface. Further use-cases of gamification and rehabilitation were also examined alongside integration of eye-tracking and gesture recognition for a sensor fusion approach to HCI and user intent.

Enhancement of GPR Diffracted Waves Processing: A Case Study from Taiyuan, China

2019 ◽  
Vol 24 (2) ◽  
pp. 237-247
Author(s):  
Hongyan Shen ◽  
Yueying Yan ◽  
Xinxin Li ◽  
Xin Wan ◽  
Qin Li ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Processing Technique ◽  
Geological Surveys ◽  
Energy Scaling ◽  
Diffracted Waves ◽  
Band Pass ◽  
Time Distance ◽  
Value Decomposition ◽  
Ground Penetrating

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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