Discrete Wavelet Transforms-Based Analysis of Accelerometer Signals for Continuous Human Cardiac Monitoring

Measuring cardiac activity from the chest using an accelerometer is commonly referred to as seismocardiography. Unfortunately, it cannot provide clinically valid data because it is easily corrupted by motion artefacts. This paper proposes two methods to improve peak detection from noisy seismocardiography data. They rely on discrete wavelet transform analysis using either biorthogonal 3.9 or reverse biorthogonal 3.9. The first method involves slicing chest vibrations for each cardiac activity, and then detecting the peak location, whereas the other method aims at detecting the peak directly from chest vibrations without segmentation. Performance evaluations were conducted on signals recorded from small children and adults based on missing and additional peaks. Both algorithms showed a low error rate (15.4% and 2.1% for children/infants and adults, respectively) for signals obtained in resting state. The average error for sitting and breathing tasks (adults only) was 14.4%. In summary, the first algorithm proved more promising for further exploration.

Simplifying the hardware requirements for fast neural EIT of peripheral nerves

Objective: The main objective of this study was to assess the feasibility of lowering the hardware requirements for fast neural EIT in order to support the distribution of this technique. Specifically, the feasibility of replacing the commercial modules present in the existing high-end setup with compact and cheap customized circuitry was assessed. Approach: Nerve EIT imaging was performed on rat sciatic nerves with both our standard ScouseTom setup and a customized version in which commercial benchtop current sources were replaced by custom circuitry. Electrophysiological data and images collected in the same experimental conditions with the two setups were compared. Data from the customized setup was subject to a down-sampling analysis to simulate the use of a recording module with lower specifications. Main results: Compound action potentials (573±287µV and 487±279µV, p=0.28) and impedance changes (36±14µV and 31±16µV, p=0.49) did not differ significantly when measured using commercial high-end current sources or our custom circuitry, respectively. Images reconstructed from both setups showed neglibile (<1voxel, i.e. 40µm) difference in peak location and a high degree of correlation (R2=0.97). When down-sampling from 24 to 16 bits ADC resolution and from 100KHz to 50KHz sampling frequency, signal-to-noise ratio showed acceptable decrease (<-20%), and no meaningful image quality loss was detected (peak location difference <1voxel, pixel-by-pixel correlation R2=0.99). Significance: The technology developed for this study greatly reduces the cost and size of a fast neural EIT setup without impacting quality and thus promotes the adoption of this technique by the neuroscience research community.

F0 Peak Alignment, F0 Peak Location, and Focus Perception in Taif Arabic

The encoding of focus and its role in Taif Arabic has not been understood fully. A recent production study found significant acoustic differences between syntactically identical utterances with focus and without focus. The current study aims to investigate further F0 peak alignment, F0 peak location and (b) focus perception in Taif Arabic. The acoustic analyses of F0 peak alignment and F0 peak location show that only the F0 peak alignment of the post-focus words was realized earlier than that of their counterparts under neutral-focus condition, and the location of the F0 peak of the stressed syllable of the post-focus words was lower than that of their counterparts in neutral-focus utterances. In focus perception, correct focus identification was 85% for initial focus and 71% for penultimate focus. These findings have implications for both focus typology and language variations.

Zonal shift in the cold airmass stream of the East Asian winter monsoon

The East Asian winter monsoon exhibits long-term variations in intensity and spatial pattern, though the latter one is less understood. To investigate the long-term spatial variations of the EAWM and their possible causes, we propose a new position index of the EAWM by quantifying the low-level East Asian stream (EAS) of cold airmass in the Lagrangian sense. Based on the new-defined index, we find that the EAS undergoes an evident zonal shift between two channels over the land and coast. At interdecadal timescale, the peak location of the EAS is displaced eastward, with an increasing southward cold airmass flux at the coast since the mid-1960s. The interannual shift of the EAS presents not only the zonal oscillation of peak location between two channels but also the width changes of coastal channel over the northwestern Pacific. These shifts in the EAS are related to the strength changes of two source cold airmass streams from Siberia or Bering Sea, which are associated with the phase changes in the upper-tropospheric atmospheric teleconnections. At interdecadal timescale, the phase change in the North Atlantic Oscillation modulates the zonal shift in the EAS via the East Atlantic-West Russia teleconnection. At interannual timescale, the Pacific/North American teleconnection becomes the dominant factor altering the zonal shift and width change of the EAS.

Theoretical Investigation of the Modeling of Indole –dichlormethane Hydrogen Bonding in Different Solvents

Theoretical vibrational spectra of indole (IND) and its binary combination with dichloromethane (DC) in various solvents were computed to track the impact of molecular interactions on drug spectral characteristics. When transitioning from plain drug to complexes, 3561.26 cm− 1 mode of the IND displays a substantial shift in peak location. The 3561.26 band shows (~ 15.58) red shift upon dilution. The geometry of drug and IND-DC complex in various solvents was calculated using quantum chemical calculation utilizing DFT.

Bézier curves as a total approach to measure the upper lid contour: redefining clinical outcomes in palpebral surgery

AimsTo define and quantify the upper lid contour by adapting Bézier curves with a newly developed software in normal subjects, assessing their reliability.MethodsFifty eyes of 50 healthy patients with no ocular pathology were included in this study from October 2020 to November 2020. All measurements were performed on Bézier curves adjusted to the upper lid contour. An original software was used to measure the radial and vertical midpupil-to-lid margin distances (MPLD), temporal-to-nasal (T/N) ratios, contour peak location and grade of superposition (GS) and asymmetry (GA) indexes. We calculated differences in the variables measured regarding age, gender or the side of the eye being assessed.ResultsThe mean Bézier curve showed an excellent level of inter-rater reliability (intraclass correlation coefficient of 0.99). The median GS index of each eyelid to the mean Bézier curve was 95.4%, 8.5 IQR, and the median GA index was 3%, 3.4 IQR. The mean contour peak location was −0.35 mm, SD 0.45. Overall, the mean central MPLD was 4.1 mm, SD 0.6. No significant differences were found between male and female patients in variables derived from Bézier curves.ConclusionBézier curves may become a very useful tool for the assessment of upper lid contour, contour peak and symmetry. GS and GA indexes, along with the T/N area ratio are potential outcomes for this purpose. All current variables can be obtained just from one single Bézier curve measurement. Our results offer an in-depth exhaustive description of these variables and their distribution in the normal population.

A Statistical Estimation of the Occurrence of Extraterrestrial Intelligence in the Milky Way Galaxy

In the field of astrobiology, the precise location, prevalence, and age of potential extraterrestrial intelligence (ETI) have not been explicitly explored. Here, we address these inquiries using an empirical galactic simulation model to analyze the spatial–temporal variations and the prevalence of potential ETI within the Galaxy. This model estimates the occurrence of ETI, providing guidance on where to look for intelligent life in the Search for ETI (SETI) with a set of criteria, including well-established astrophysical properties of the Milky Way. Further, typically overlooked factors such as the process of abiogenesis, different evolutionary timescales, and potential self-annihilation are incorporated to explore the growth propensity of ETI. We examine three major parameters: (1) the likelihood rate of abiogenesis (λA); (2) evolutionary timescales (Tevo); and (3) probability of self-annihilation of complex life (Pann). We found Pann to be the most influential parameter determining the quantity and age of galactic intelligent life. Our model simulation also identified a peak location for ETI at an annular region approximately 4 kpc from the galactic center around 8 billion years (Gyrs), with complex life decreasing temporally and spatially from the peak point, asserting a high likelihood of intelligent life in the galactic inner disk. The simulated age distributions also suggest that most of the intelligent life in our galaxy are young, thus making observation or detection difficult.

Influence of Neighborhood Size and Cross-Correlation Peak-Fitting Method on Location Accuracy

A known technique to obtain subpixel resolution by using object tracking through cross-correlation consists of interpolating the obtained correlation function and then refining peak location. Although the technique provides accurate results, peak location is usually biased toward the closest integer coordinate. This effect is known as the peak-locking error and it strongly limits this calculation technique’s experimental accuracy. This error may differ depending on the scene and algorithm used to fit and interpolate the correlation peak, but in general, it may be attributed to a sampling problem and the presence of aliasing. Many studies in the literature analyze this effect in the Fourier domain. Here, we propose an alternative analysis on the spatial domain. According to our interpretation, the peak-locking error may be produced by a non-symmetrical sample distribution, thus provoking a bias in the result. According to this, the peak interpolant function, the size of the local domain and low-pass filters play a relevant role in diminishing the error. Our study explores these effects on different samples taken from the DIC Challenge database, and the results show that, in general, peak fitting with a Gaussian function on a relatively large domain provides the most accurate results.

Application of the Approximate Bayesian Computation Algorithm to Gamma-Ray Spectroscopy

Radioisotope identification (RIID) algorithms for gamma-ray spectroscopy aim to infer what isotopes are present and in what amounts in test items. RIID algorithms either use all energy channels in the analysis region or only energy channels in and near identified peaks. Because many RIID algorithms rely on locating peaks and estimating each peak’s net area, peak location and peak area estimation algorithms continue to be developed for gamma-ray spectroscopy. This paper shows that approximate Bayesian computation (ABC) can be effective for peak location and area estimation. Algorithms to locate peaks can be applied to raw or smoothed data, and among several smoothing options, the iterative bias reduction algorithm (IBR) is recommended; the use of IBR with ABC is shown to potentially reduce uncertainty in peak location estimation. Extracted peak locations and areas can then be used as summary statistics in a new ABC-based RIID. ABC allows for easy experimentation with candidate summary statistics such as goodness-of-fit scores and peak areas that are extracted from relatively high dimensional gamma spectra with photopeaks (1024 or more energy channels) consisting of count rates versus energy for a large number of gamma energies.