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1. Heart Rate Variability in Schizophrenia and Autism

   https://doi.org/10.3389/fpsyt.2021.760396  

   Haigh, Sarah M.; Walford, Tabatha P.; Brosseau, Pat (November 2021, Frontiers in Psychiatry)

   Suppressed heart rate variability (HRV) has been found in a number of psychiatric conditions, including schizophrenia and autism. HRV is a potential biomarker of altered autonomic functioning that can predict future physiological and cognitive health. Understanding the HRV profiles that are unique to each condition will assist in generating predictive models of health. In the current study, we directly compared 12 adults with schizophrenia, 25 adults with autism, and 27 neurotypical controls on their HRV profiles. HRV was measured using an electrocardiogram (ECG) channel as part of a larger electroencephalography (EEG) study. All participants also completed the UCLA Loneliness Questionnaire as a measure of social stress. We found that the adults with schizophrenia exhibited reduced variability in R-R peaks and lower low frequency power in the ECG trace compared to controls. The HRV in adults with autism was slightly suppressed compared to controls but not significantly so. Interestingly, the autism group reported feeling lonelier than the schizophrenia group, and HRV did not correlate with feelings of loneliness for any of the three groups. However, suppressed HRV was related to worse performance on neuropsychological tests of cognition in the schizophrenia group. Together, this suggests that autonomic functioning is more abnormal in schizophrenia than in autism and could be reflecting health factors that are unique to schizophrenia. 

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2. Lightning Geolocation and Flash Rates From LF Radio Observations During the RELAMPAGO Field Campaign

   https://doi.org/10.1029/2021EA001813  

   Antunes de Sá, A.; Marshall, R.; Deierling, W. (October 2021, Earth and Space Science)

   Abstract The lightning data products generated by the low‐frequency (LF) radio lightning locating system (LLS) deployed during the Remote sensing of Electrification, Lightning, and Mesoscale/Microscale Processes with Adaptive Ground Observation (RELAMPAGO) field campaign in Argentina provide a valuable data set to research the lightning evolution and characteristics of convective storms that produce high‐impact weather. LF LLS data sets offer a practical range for mesoscale studies, allowing for the observation of lightning characteristics of storms such as mesoscale convective systems or large convective lines that travel longer distances which are not necessarily staying in range of regional VHF‐based lightning detection systems throughout their lifetime. LF LLSs also provide different information than optical space‐borne lightning detectors. Lightning measurements exclusive to LF systems include discharge peak current, lightning polarity, and lightning type classification based on the lightning‐emitted radio waveform. Furthermore, these measurements can provide additional information on flash rates (e.g., positive cloud‐to‐ground flash rate) or narrow bipolar events which may often be associated with dynamically intense convection. In this article, the geolocation and data processing of the LF data set collected during RELAMPAGO is fully described and its performance characterized, with location accuracy better than 10 km. The detection efficiency (DE) of the data set is compared to that of the Geostationary Lightning Mapper, and spatiotemporal DE losses in the LF data set are discussed. Storm case studies on November 10, 2018, highlight the strengths of the data set, which include robust flash clustering and insightful flash rate and peak current measures, while illustrating how its limitations, including DE losses, can be managed. 

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3. Flickering Low Frequency Auroral Hiss

   https://doi.org/10.1029/2020JA029098  

   LaBelle, James (April 2021, Journal of Geophysical Research: Space Physics)

   Abstract A low‐ and medium‐frequency (LF/MF) receiving system at South Pole Station, using a wide‐beam dipole antenna, measured continuous fully sampled waveforms of more than 100 LF auroral hiss events between June and October 2019. Spectra of fluctuations of LF auroral hiss intensity at selected frequencies between 110 and 530 kHz showed these are broadband, with spectral power monotonically decreasing to an upper bound typically 20–60 Hz, comparable to frequencies reported for optical flickering aurora. Occasionally intervals of periodic fluctuations in auroral hiss intensity occurred, in most cases lasting only tens of cycles. On September 1, 2019, periodic fluctuations lasted thousands of cycles during two 30‐s intervals, at frequencies 125–145 Hz. Close examination showed these to be dispersed with low frequencies arriving before high frequencies by approximately 4.5 ms per 100 kHz. Ray‐tracing calculations and consideration of the Temerin et al. (1986, 1993) mechanisms of flickering aurora shows that the September 1 flickering auroral hiss observations are consistent with resonant amplification of whistler mode noise by an electron beam accelerated and modulated by electromagnetic proton cyclotron waves originating near 4,500 km, with the wave excitation taking place at 2,000–3,000 km. 

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4. Interpolating Hydrologic Data Using Laplace Formulation

   https://doi.org/10.3390/rs15153844  

   Xu, Tianle; Merwade, Venkatesh; Wang, Zhiquan (August 2023, Remote Sensing)

   Spatial interpolation techniques play an important role in hydrology, as many point observations need to be interpolated to create continuous surfaces. Despite the availability of several tools and methods for interpolating data, not all of them work consistently for hydrologic applications. One of the techniques, the Laplace Equation, which is used in hydrology for creating flownets, has rarely been used for data interpolation. The objective of this study is to examine the efficiency of Laplace formulation (LF) in interpolating data used in hydrologic applications (hydrologic data) and compare it with other widely used methods such as inverse distance weighting (IDW), natural neighbor, and ordinary kriging. The performance of LF interpolation with other methods is evaluated using quantitative measures, including root mean squared error (RMSE) and coefficient of determination (R2) for accuracy, visual assessment for surface quality, and computational cost for operational efficiency and speed. Data related to surface elevation, river bathymetry, precipitation, temperature, and soil moisture are used for different areas in the United States. RMSE and R2 results show that LF is comparable to other methods for accuracy. LF is easy to use as it requires fewer input parameters compared to inverse distance weighting (IDW) and Kriging. Computationally, LF is faster than other methods in terms of speed when the datasets are not large. Overall, LF offers a robust alternative to existing methods for interpolating various hydrologic data. Further work is required to improve its computational efficiency. 

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5. Protein Signal Enhancements with Polar Organic Ester Vapor Addition in Desorption and Electrospray Ionization

   Taylor, Christopher J; Venter, Andre R (June 2025, American Society for Mass Spectrometry)

   Introduction Previous work has shown that exposure of electrospray droplets to ethyl acetate produce spectra with more intense protein signal, as well as protein envelopes shifted toward higher charge states . This is of specific interest when carrying out DESI-MS analysis, as the technique struggles to analyze proteins larger than 25 kDa in size due to poor dissolution and adduction. . The mechanism by which ethyl acetate improves responses was studied by analyzing protein molecules in atmospheres modified with ethyl acetate and related polar organic compounds, and an analogue series of esters with increasing chain lengths. Methods All spectra were collected using a Thermo LTQ XL mass spectrometer. ESI samples were 2.5 μM cytochrome C, myoglobin or lysozyme in 80% methanol with 0.1% formic acid or in aqueous 100mM ammonium acetate. A polypropylene enclosure for introduction of additive to the atmospheric region around the ion source and transfer tube was constructed . Liquid additives were introduced at a controlled, continuous, flow rate of 70 μL/min onto a flash chromatography pad acting as a reservoir inside of the enclosure. The additive was allowed to evaporate from the reservoir pad to saturate the ionization region. Relative changes in signals upon vapor additions were reported as the ratio to enclosed signal without vapor modification. Preliminary Data Our results indicate dependence on the alkyl chain length on either side of the ester functional group. By increasing the alkyl chain length of alcohol and carboxylic acid precursors, the hydrophobicity of esters also increases. Longer alkyl chains proton affinities of these molecules. Proteins were analyzed from denaturing conditions and ionization is believed to occur through the chain ejection model (CEM). We suggest that the increasing hydrophobicity of the esters may increasingly aid in lowering the energy barrier of transfer of the denatured protein from the solvated state in bulk droplet to the gas phase. This might be a consequence of the formation of a condensed ester on the evaporative cooled microdroplet, or a gas phase interaction. The degree of improvement when modifying the ionization region with esters initially shows little to no increase when using those with smaller alkyl chains (C3, C4). With longer chains (C7), however, dramatic improvements in protein signal can be observed. This is particularly evident when analyzing higher charge state peaks corresponding to more unfolded protein populations, such peaks corresponding to more unfolded protein populations. This effect may be due to competition between vapor pressure of the atmospheric modifiers and hydrophobic interactions between the modifier and ejecting protein. Vapor pressure drastically decreases between ethyl acetate to longer chain esters such as butyl acetate. Additional heating of the pad will be investigated to compensate for this trade-off. . With even longer chain esters, such as ethyl heptanoate, we see a greater improvement, indicating that their increased hydrophobic character and resultant analyte interactions is more favorable. As well, the improved signal observed for higher charge state peaks consequently increases the protein average charge state. Novel Aspect Vapor addition of esters with increasing chain lengths to the atmospheric ionization region improve protein detection by electrospray-based methods 

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