Some Rationale for the Unusual Behavior of the Dielectric Constant of Cu2O

1973 ◽  
Vol 51 (6) ◽  
pp. 680-685 ◽  
Author(s):  
F. L. Weichman
Keyword(s):  
Dielectric Constant ◽  
High Frequency ◽  
Low Temperatures ◽  
Low Frequency ◽  
Depletion Layer ◽  
Temperature Dependent ◽  
Unusual Behavior ◽  
Temperature Variations ◽  
Very Low Frequency ◽  
Semiconducting Material

The very low frequency dielectric constant in Cu2O varies over wide limits and is highly temperature dependent. At sufficiently low temperatures the dielectric constant for all samples reduces to the high frequency value of about 7.5. Small variations in the high frequency value are easily explained as being due to the known presence of copper crystals embedded in the semiconducting material. The low frequency and temperature variations will be related to the variation in the depletion layer formed around each copper inclusion. Calculations are based on highly oversimplified size, shape, and distribution of the copper inclusions.

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 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 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 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.

Scaling exponent values as an ordinary function of the ratio of very low frequency to high frequency powers in heart rate variability over various sleep stages

2016 ◽  
Vol 20 (3) ◽  
pp. 975-985 ◽  
Author(s):  
Ren-Jing Huang ◽  
Ching-Hsiang Lai ◽  
Shin-Da Lee ◽  
Wei-Che Wang ◽  
Ling-Hui Tseng ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Low Frequency ◽  
Sleep Stages ◽  
Scaling Exponent ◽  
Very Low Frequency

Heart rate variability and dissociation in panic disorder

2011 ◽  
Vol 26 (S2) ◽  
pp. 147-147
Author(s):  
T. Diveky ◽  
D. Kamaradova ◽  
A. Grambal ◽  
K. Latalova ◽  
J. Prasko ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Panic Disorder ◽  
Frequency Band ◽  
High Frequency ◽  
Power Spectra ◽  
Low Frequency ◽  
Very Low Frequency ◽  
Significant Difference ◽  
Before And After

The aim of our study is to measure very low frequency band (VLF), low frequency band (LF) and high frequency band (HF) components of R-R interval during orthostatic experiment in panic disorder patients before and after treatment.MethodsWe assessed heart rate variability in 19 patients with panic disorder before and after 6-weeks treatment with antidepressants combined with CBT and 18 healthy controls. They were regularly assessed on the CGI, BAI and BDI. Heart rate variability was assessed during 5 min standing, 5 min supine and 5 min standing positions before and after the treatment. Power spectra were computed using a fast Fourier transformation for very low frequency - VLF (0.0033 - 0.04 Hz), low-frequency - LF (0.04-0.15 Hz) and high frequency - HF (0.15-0.40 Hz) powers.Results19 panic disorder patients entered a 6-week open-label treatment study with combination of SSRI and cognitive behavioral therapy. A combination of CBT and pharmacotherapy proved to be the effective treatment of patients. They significantly improved in all rating scales. There were highly statistical significant differences between panic patients and control group in all components of power spectral analysis in 2nd and in two component of 3rd (LF and HF in standing) positions. There was also statistically significant difference between these two groups in LF/HF ratio in supine position (2nd). During therapy there was tendency to increasing values in all three positions in components of HRV power spectra, but there was only statistically significant increasing in HF1 component.Supported by project IGA MZ ČR NS 10301-3/2009

DIELECTRIC EVIDENCE FOR ACETONE HYDRATE

1963 ◽  
Vol 41 (2) ◽  
pp. 264-273 ◽  
Author(s):  
G. J. Wilson ◽  
D. W. Davidson
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
High Frequency ◽  
Water System ◽  
Low Frequency ◽  
Water Molecules ◽  
Incongruent Melting ◽  
High Frequency Dielectric Constant ◽  
System A ◽  
Acetone Water

The phase diagram of the acetone–water system shows that acetone hydrate decomposes at an incongruent melting point. The existence of acetone hydrate is confirmed by a study of the low-frequency dielectric properties of this system. A dispersion region, related to the relaxation of water molecules in the clathrate structure, is characterized by a "static" dielectric constant and an activation energy about half as large as the corresponding values for ice, and by a limiting high-frequency dielectric constant of about 7 at 200° K. The magnitude of the latter is attributed to orientation of acetone molecules within the larger cavities of the hydrate structure.

scholarly journals Dynamic cerebral autoregulation during passive heat stress in humans

2009 ◽  
Vol 296 (5) ◽  
pp. R1598-R1605 ◽  
Author(s):  
David A. Low ◽  
Jonathan E. Wingo ◽  
David M. Keller ◽  
Scott L. Davis ◽  
Jian Cui ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heat Stress ◽  
Transfer Function ◽  
High Frequency ◽  
Cerebral Autoregulation ◽  
Low Frequency ◽  
Passive Heating ◽  
Frequency Range ◽  
Very Low Frequency ◽  
Dynamic Cerebral Autoregulation

This study tested the hypothesis that passive heating impairs cerebral autoregulation. Transfer function analyses of resting arterial blood pressure and middle cerebral artery blood velocity (MCA Vmean), as well as MCA Vmean and blood pressure responses to rapid deflation of previously inflated thigh cuffs, were examined in nine healthy subjects under normothermic and passive heat stress (increase core temperature 1.1 ± 0.2°C, P < 0.001) conditions. Passive heating reduced MCA Vmean [change (Δ) of 8 ± 8 cm/s, P = 0.01], while blood pressure was maintained (Δ −1 ± 4 mmHg, P = 0.36). Coherence was decreased in the very-low-frequency range during heat stress (0.57 ± 0.13 to 0.26 ± 0.10, P = 0.001), but was >0.5 and similar between normothermia and heat stress in the low- (0.07–0.20 Hz, P = 0.40) and high-frequency (0.20–0.35 Hz, P = 0.12) ranges. Transfer gain was reduced during heat stress in the very-low-frequency (0.88 ± 0.38 to 0.59 ± 0.19 cm·s−1·mmHg−1, P = 0.02) range, but was unaffected in the low- and high-frequency ranges. The magnitude of the decrease in blood pressure (normothermia: 20 ± 4 mmHg, heat stress: 19 ± 6 mmHg, P = 0.88) and MCA Vmean (13 ± 4 to 12 ± 6 cm/s, P = 0.59) in response to cuff deflation was not affected by the thermal condition. Similarly, the rate of regulation of cerebrovascular conductance (CBVC) after cuff release (0.44 ± 0.22 to 0.38 ± 0.13 ΔCBVC units/s, P = 0.16) and the time for MCA Vmean to recover to precuff deflation baseline (10.0 ± 7.9 to 8.7 ± 4.9 s, P = 0.77) were not affected by heat stress. Counter to the proposed hypothesis, similar rate of regulation responses suggests that heat stress does not impair the ability to control cerebral perfusion after a rapid reduction in perfusion pressure, while reduced transfer function gain and coherence in the very-low-frequency range during heat stress suggest that dynamic cerebral autoregulation is improved during spontaneous oscillations in blood pressure within this frequency range.

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