scholarly journals Pre-Emption of Affliction Severity Using HRV Measurements from a Smart Wearable; Case-Study on SARS-Cov-2 Symptoms

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7068
Author(s):  
Gatha Tanwar ◽  
Ritu Chauhan ◽  
Madhusudan Singh ◽  
Dhananjay Singh
Keyword(s):  
High Frequency ◽  
Viterbi Algorithm ◽  
Low Frequency ◽  
Very Low Frequency ◽  
Internal States ◽  
Hidden States ◽  
Complications And Mortality ◽  
Smart Wearable

Smart wristbands and watches have become an important accessory to fitness, but their application to healthcare is still in a fledgling state. Their long-term wear facilitates extensive data collection and evolving sensitivity of smart wristbands allows them to read various body vitals. In this paper, we hypothesized the use of heart rate variability (HRV) measurements to drive an algorithm that can pre-empt the onset or worsening of an affliction. Due to its significance during the time of the study, SARS-Cov-2 was taken as the case study, and a hidden Markov model (HMM) was trained over its observed symptoms. The data used for the analysis was the outcome of a study hosted by Welltory. It involved the collection of SAR-Cov-2 symptoms and reading of body vitals using Apple Watch, Fitbit, and Garmin smart bands. The internal states of the HMM were made up of the absence and presence of a consistent decline in standard deviation of NN intervals (SSDN), the root mean square of the successive differences (rMSSD) in R-R intervals, and low frequency (LF), high frequency (HF), and very low frequency (VLF) components of the HRV measurements. The emission probabilities of the trained HMM instance confirmed that the onset or worsening of the symptoms had a higher probability if the HRV components displayed a consistent decline state. The results were further confirmed through the generation of probable hidden states sequences using the Viterbi algorithm. The ability to pre-empt the exigent state of an affliction would not only lower the chances of complications and mortality but may also help in curbing its spread through intelligence-backed decisions.

Generation of extra and very low-frequency (ELF/VLF) radiation by ionospheric electrojet modulation using high-frequency (HF) heating waves

2002 ◽  
Vol 68 (4) ◽  
pp. 267-284 ◽  
Author(s):  
S. P. KUO
Keyword(s):  
High Frequency ◽  
Thermal Instability ◽  
Loss Rate ◽  
Inelastic Collision ◽  
Modulation Frequency ◽  
Low Frequency ◽  
Heating Power ◽  
Very Low Frequency ◽  
Hf Heating ◽  
Heating Wave

Extra and very low-frequency (ELF/VLF) wave generation by modulated polar electrojet currents is studied numerically. Through Ohmic heating by the amplitude-modulated high-frequency heating wave, the conductivity and thus the current of the electrojet are modulated accordingly to set up the ionospheric antenna current. Stimulated thermal instability, which can further enhance the electrojet current modulation, is studied. It is first analysed analytically to determine the threshold heating power for its excitation. The nonlinear evolutions of the generated ELF/VLF waves enhanced by the instability are then studied numerically. Their spectra are also evaluated. The field intensity of the emission at the fundamental modulation frequency is found to increase with the modulation frequency in agreement with the Tromso observations. The efficiency enhancement by the stimulated thermal instability is hampered by inelastic collisions of electrons with neutral particles (mainly due to vibration excitation of N2), which cause this instability to saturate at low levels. However, the electron inelastic collision loss rate drops rapidly to a low value in the energy regime from 3.5 to 6 eV. As the heating power exceeds a threshold level, significant electron heating enhanced by the instability is shown, which indeed causes a steep drop in the electron inelastic collision loss rate. Consequently, this instability saturates at a much higher level, resulting to a near step increase (of about 10–13 dB depending on the modulation wave form) in the spectral intensity of ELF radiation. The dependence of the threshold power of the HF heating wave on the modulation frequency is determined.

scholarly journals Very Low Frequency Electromagnetic Induction Surveys in Hydrogeological Investigations; Case Study from Poland

2016 ◽  
Vol 64 (6) ◽  
pp. 2322-2336 ◽  
Author(s):  
Szymon Oryński ◽  
Marta Okoń ◽  
Wojciech Klityński
Keyword(s):  
Electromagnetic Induction ◽  
Low Frequency ◽  
Very Low Frequency

scholarly journals Investigation of Native Speaker and Second Language Learner Intuition of Collocation Frequency

2021 ◽  
Author(s):  
Anna Siyanova ◽  
S Spina
Keyword(s):  
Language Learning ◽  
High Frequency ◽  
Native Speakers ◽  
Native Speaker ◽  
Low Frequency ◽  
Language Learner ◽  
Very Low Frequency ◽  
Second Language Learner ◽  
L2 Learners ◽  
L1 And L2

© 2015 Language Learning Research Club, University of Michigan. Research into frequency intuition has focused primarily on native (L1) and, to a lesser degree, nonnative (L2) speaker intuitions about single word frequency. What remains a largely unexplored area is L1 and L2 intuitions about collocation (i.e., phrasal) frequency. To bridge this gap, the present study aimed to answer the following question: How do L2 learners and native speakers compare against each other and corpora in their subjective judgments of collocation frequency? Native speakers and learners of Italian were asked to judge 80 noun-adjective pairings as one of the following: high frequency, medium frequency, low frequency, very low frequency. Both L1 and L2 intuitions of high frequency collocations correlated strongly with corpus frequency. Neither of the two groups of participants exhibited accurate intuitions of medium and low frequency collocations. With regard to very low frequency pairings, L1 but not L2 intuitions were found to correlate with corpora for the majority of the items. Further, mixed-effects modeling revealed that L2 learners were comparable to native speakers in their judgments of the four frequency bands, although some differences did emerge. Taken together, the study provides new insights into the nature of L1 and L2 intuitions about phrasal frequency.

scholarly journals Can a simple, short-term memory task help to screen dyslexia?

2019 ◽  
Author(s):  
Nick Perham ◽  
Toni Howell ◽  
Andy Watt
Keyword(s):  
High Frequency ◽  
Short Term Memory ◽  
Memory Task ◽  
Compulsory Education ◽  
Low Frequency ◽  
Short Term ◽  
Term Order ◽  
Significant Difference ◽  
Support Students

AbstractFunding to support students with dyslexia in post-compulsory education is under pressure and more efficient assessments may offset some of this shortfall. We tested potential tasks for screening dyslexia: recall of adjective-noun, compared to noun-adjective, pairings (syntax) and recall of high versus low frequency letter pairings (bigrams). Students who reported themselves as dyslexic failed to show a normal syntax effect (greater recall of adjective-noun compared to noun-adjective pairings) and no significant difference in recall between the two types of bigrams whereas students who were not dyslexic showed the syntax effect and a bias towards recalling high frequency bigrams. Findings are consistent with recent explanations of dyslexia suggesting that those affected find it difficult to learn and utilise sequential long-term order information (Szmalec et al. Journal of Experimental Psychology: Learning, Memory & Cognition, 37(5) ,1270-1279, 2011). Further, ROC curve analyses revealed both tasks showed acceptable diagnostic properties as they were able to discriminate between the two groups of participants.

scholarly journals Effect of Closed-Loop Vibration Stimulation on Heart Rhythm during Naps

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4136 ◽  
Author(s):  
Sang Ho Choi ◽  
Heenam Yoon ◽  
Hyung Won Jin ◽  
Hyun Bin Kwon ◽  
Seong Min Oh ◽  
...  
Keyword(s):  
High Frequency ◽  
Closed Loop ◽  
Low Frequency ◽  
Heart Rhythm ◽  
Quality Of Sleep ◽  
Stimulation Condition ◽  
Term Basis ◽  
Stimulation System

Sleep plays a primary function for health and sustains physical and cognitive performance. Although various stimulation systems for enhancing sleep have been developed, they are difficult to use on a long-term basis. This paper proposes a novel stimulation system and confirms its feasibility for sleep. Specifically, in this study, a closed-loop vibration stimulation system that detects the heart rate (HR) and applies −n% stimulus beats per minute (BPM) computed on the basis of the previous 5 min of HR data was developed. Ten subjects participated in the evaluation experiment, in which they took a nap for approximately 90 min. The experiment comprised one baseline and three stimulation conditions. HR variability analysis showed that the normalized low frequency (LF) and LF/high frequency (HF) parameters significantly decreased compared to the baseline condition, while the normalized HF parameter significantly increased under the −3% stimulation condition. In addition, the HR density around the stimulus BPM significantly increased under the −3% stimulation condition. The results confirm that the proposed stimulation system could influence heart rhythm and stabilize the autonomic nervous system. This study thus provides a new stimulation approach to enhance the quality of sleep and has the potential for enhancing health levels through sleep manipulation.

Robust Changes of Afferent-Induced Excitation in the Rat Spinal Dorsal Horn After Conditioning High-Frequency Stimulation

2000 ◽  
Vol 83 (4) ◽  
pp. 2412-2420 ◽  
Author(s):  
Hiroshi Ikeda ◽  
Tatsuya Asai ◽  
Kazuyuki Murase
Keyword(s):  
Dorsal Horn ◽  
High Frequency ◽  
Low Frequency ◽  
Single Pulse ◽  
High Frequency Stimulation ◽  
Neuronal Excitation ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Stimulation Of

We investigated the neuronal plasticity in the spinal dorsal horn and its relationship with spinal inhibitory networks using an optical-imaging method that detects neuronal excitation. High-intensity single-pulse stimulation of the dorsal root activating both A and C fibers evoked an optical response in the lamina II (the substantia gelatinosa) of the dorsal horn in transverse slices of 12- to 25-day-old rat spinal cords stained with a voltage-sensitive dye, RH-482. The optical response, reflecting the net neuronal excitation along the slice-depth, was depressed by 28% for more than 1 h after a high-frequency conditioning stimulation of A fibers in the dorsal root (3 tetani of 100 Hz for 1 s with an interval of 10 s). The depression was not induced in a perfusion solution containing an NMDA antagonist,dl-2-amino-5-phosphonovaleric acid (AP5; 30 μM). In a solution containing the inhibitory amino acid antagonists bicuculline (1 μM) and strychnine (3 μM), and also in a low Cl−solution, the excitation evoked by the single-pulse stimulation was enhanced after the high-frequency stimulation by 31 and 18%, respectively. The enhanced response after conditioning was depotentiated by a low-frequency stimulation of A fibers (0.2–1 Hz for 10 min). Furthermore, once the low-frequency stimulation was applied, the high-frequency conditioning could not potentiate the excitation. Inhibitory transmissions thus regulate the mode of synaptic plasticity in the lamina II most likely at afferent terminals. The high-frequency conditioning elicits a long-term depression (LTD) of synaptic efficacy under a greater activity of inhibitory amino acids, but it results in a long-term potentiation (LTP) when inhibition is reduced. The low-frequency preconditioning inhibits the potentiation induction and maintenance by the high-frequency conditioning. These mechanisms might underlie robust changes of nociception, such as hypersensitivity after injury or inflammation and pain relief after electrical or cutaneous stimulation.

scholarly journals Impact of Catheter Ablation on Sleep Quality and Relationship Between Sleep Stability and Recurrence of Paroxysmal Atrial Fibrillation After Successful Ablation: 24‐Hour Holter‐Based Cardiopulmonary Coupling Analysis

2020 ◽  
Vol 9 (23) ◽  
Author(s):  
Woohyeun Kim ◽  
Jin Oh Na ◽  
Robert J. Thomas ◽  
Won Young Jang ◽  
Dong Oh Kang ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Catheter Ablation ◽  
Sleep Quality ◽  
High Frequency ◽  
Low Frequency ◽  
Coupling Analysis ◽  
Very Low Frequency ◽  
Cardiopulmonary Coupling ◽  
Frequency Coupling ◽  
Af Recurrence

Background Sleep fragmentation and sleep apnea are common in patients with atrial fibrillation (AF). We investigated the impact of radio‐frequency catheter ablation (RFCA) on sleep quality in patients with paroxysmal AF and the effect of a change in sleep quality on recurrence of AF. Methods and Results Of 445 patients who underwent RFCA for paroxysmal AF between October 2007 and January 2017, we analyzed 225 patients who had a 24‐hour Holter test within 6 months before RFCA. Sleep quality was assessed by cardiopulmonary coupling analysis using 24‐hour Holter data. We compared cardiopulmonary coupling parameters (high‐frequency coupling, low‐frequency coupling, very‐low‐frequency coupling) before and after RFCA. Six months after RFCA, the high‐frequency coupling (marker of stable sleep) and very‐low‐frequency coupling (rapid eye movement/wake marker) was significantly increased (29.84%–36.15%; P <0.001; and 26.20%–28.76%; P =0.002, respectively) while low‐frequency coupling (unstable sleep marker) was decreased (41.25%–32.13%; P <0.001). We divided patients into 3 tertiles according to sleep quality before RFCA, and the risk of AF recurrence in each group was compared. The second tertile was used as a reference; patients with unstable sleep (Tertile 3) had a significantly lower risk of AF recurrence (hazard ratio [HR], 0.32; 95% CI, 0.12–0.83 for high‐frequency coupling; and HR, 0.22; 95% CI, 0.09–0.58 for low‐frequency coupling). Conclusions Sleep quality improved after RFCA in patients with paroxysmal AF. The recurrence rate was significantly lower in patients who had unstable sleep before RFCA. These results suggest that RFCA can influence sleep quality, and sleep quality assessment before RFCA may provide a risk marker for recurrence after RFCA in patients with paroxysmal AF.

scholarly journals Bacteriophage Lambda: a Paradigm Revisited

2010 ◽  
Vol 84 (13) ◽  
pp. 6876-6879 ◽  
Author(s):  
Paul C. M. Fogg ◽  
Heather E. Allison ◽  
Jon R. Saunders ◽  
Alan J. McCarthy
Keyword(s):  
Escherichia Coli ◽  
Sequence Analysis ◽  
High Frequency ◽  
Southern Hybridization ◽  
Integration Site ◽  
Bacteriophage Lambda ◽  
Rare Event ◽  
Low Frequency ◽  
E Coli ◽  
Very Low Frequency

ABSTRACT Bacteriophage lambda has an archetypal immunity system, which prevents the superinfection of its Escherichia coli lysogens. It is now known that superinfection can occur with toxigenic lambda-like phages at a high frequency, and here we demonstrate that the superinfection of a lambda lysogen can lead to the acquisition of additional lambda genomes, which was confirmed by Southern hybridization and quantitative PCR. As many as eight integration events were observed but at a very low frequency (6.4 × 10−4) and always as multiple insertions at the established primary integration site in E. coli. Sequence analysis of the complete immunity region demonstrated that these multiply infected lysogens were not immunity mutants. In conclusion, although lambda superinfection immunity can be confounded, it is a rare event.

Role of Dominance Status in Shock-Stimulated Agonistic Behavior

1971 ◽  
Vol 29 (3) ◽  
pp. 768-770 ◽  
Author(s):  
G. McA. Kimbrell ◽  
D. Chesler
Keyword(s):  
High Frequency ◽  
Agonistic Behavior ◽  
Defensive Behavior ◽  
Low Frequency ◽  
Behavior Patterns ◽  
Dominance Status ◽  
Very Low Frequency ◽  
The Relationship ◽  
Shock Situation

To clarify the relationship between dominance status and frequency of specific sub-classes of agonistic behavior in response to foot shock, 30 mice were selected on the basis of high- or low-dominance status and paired in a foot-shock situation. Dominant pairs exhibit a high frequency of defensive behavior patterns whereas submissive pairs exhibit a very low frequency of defensive patterns.

scholarly journals Low-cost monitoring buoys network tracking biogeochemical changes in lakes and marine environments – a regional case study

2018 ◽  
Vol 90 (10) ◽  
pp. 1631-1646 ◽  
Author(s):  
Alejandro J. Vitale ◽  
Gerardo M.E. Perillo ◽  
Sibila A. Genchi ◽  
Andrés H. Arias ◽  
María Cintia Piccolo
Keyword(s):  
High Frequency ◽  
Low Cost ◽  
Decision Makers ◽  
Shallow Waters ◽  
Global Level ◽  
Temperate Region ◽  
Coastal Marine ◽  
The Cost

AbstractLakes, rivers, estuaries and ocean waters control many important natural functions at the regional-global level. Hence, integrative and frequent long-term water monitoring is required globally. This paper describes the main features and innovations of a low-cost monitoring buoys network (MBN) deployed in a temperate region of Argentina. The MBN was designed to record extended time series at high-frequency, which is of great value for the scientific community, as well as for decision-makers. In addition, two innovative designs belonging to two versions of moored buoys (i.e. shallow waters and coastal marine waters) were presented. It was shown that the cost of either of two versions of the buoy is low, which can be considered as the main advantage.

Sign in / Sign up

Export Citation Format

Share Document