Role Of Frequency Research Articles

Modulation of Heart Rate Variability and Brain Excitability through Acute Whole-Body Vibration: The Role of Frequency.

This cross-over study aimed to explore effects of acute whole-body vibration (WBV) at frequencies of 5-35 Hz on heart rate variability and brain excitability. Thirteen healthy physically active college students randomly completed eight interventions under the following conditions: static upright standing without vibration (CON), static squat exercise (knee flexion 150°) on the vibration platform (SSE), and static squat exercise (knee flexion 150°) combined with WBV at vibration frequency of 5, 9, 13, 20, 25, and 35 Hz. Five bouts × 30 s with a 30-s rest interval were performed for all interventions. The brain's direct current potentials (DCPs), frequency domain variables (FDV) including normalized low frequency power (nLF), normalized high frequency power (nHF) and the ratio of LF to HF (LF/HF), along with the mean heart rate (MHR) were collected and calculated before and after the WBV intervention. Results suggested that WBV frequency at 5 Hz had a substantial effect on decreasing DCPs [-2.13 μV, t(84) = -3.82, p < 0.05, g = -1.03, large] and nLF [-13%, t(84) = -2.31, p = 0.04, g = -0.62, medium]. By contrast, 20-35 Hz of acute WBV intervention considerably improved DCPs [7.58 μV, t(84) = 4.31, p < 0.05, g = 1.16, large], nLF [17%, t(84) = 2.92, p < 0.05, g = 0.79, large] and the LF/HF [0.51, t(84) = 2.86, p < 0.05, g = 0.77, large]. A strong (r = 0.7, p < 0.01) correlation between DCPs and nLF was found at 5 Hz. In summary, acute WBV at 20-35 Hz principally activated the sympathetic nervous system and increased brain excitability, while 5-Hz WBV activated the parasympathetic nervous system and reduced brain excitability. The frequency spectrum of WBV might be manipulated according to the intervention target on heart rate variability and brain excitability.

The Role of Frequency and Electromechanical Coupling on Electrical and Dielectric Properties for Lead Zirconate Titanate (PZT) Transducer.

The Role of Frequency and Electromechanical Coupling on Electrical and Dielectric Properties for Lead Zirconate Titanate (PZT) Transducer.

Distinct Spectral Profiles of Awake Resting EEG in Disorders of Consciousness: The Role of Frequency and Topography of Oscillations.

The prolonged disorders of consciousness (PDOC) pose a challenge for an accurate clinical diagnosis, mainly due to patients' scarce or ambiguous behavioral responsiveness. Measurement of brain activity can support better diagnosis, independent of motor restrictions. Methods based on spectral analysis of resting-state EEG appear as a promising path, revealing specific changes within the internal brain dynamics in PDOC patients. In this study we used a robust method of resting-state EEG power spectrum parameter extraction to identify distinct spectral properties for different types of PDOC. Sixty patients and 37 healthy volunteers participated in this study. Patient group consisted of 22 unresponsive wakefulness patients, 25 minimally conscious patients and 13 patients emerging from the minimally conscious state. Ten minutes of resting EEG was acquired during wakefulness and transformed into individual power spectra. For each patient, using the spectral decomposition algorithm, we extracted maximum peak frequency within 1-14Hz range in the centro-parietal region, and the antero-posterior (AP) gradient of the maximal frequency peak. All patients were behaviorally diagnosed using coma recovery scale-revised (CRS-R). The maximal peak frequency in the 1-14Hz range successfully predicted both neurobehavioral capacity of patients as indicated by CRS-R total score and PDOC diagnosis. Additionally, in patients in whom only one peak within the 1-14Hz range was observed, the AP gradient significantly contributed to the accuracy of prediction. We have identified three distinct spectral profiles of patients, likely representing separate neurophysiological modes of thalamocortical functioning. Etiology did not have significant influence on the obtained results.

The Role of Frequency and Impedance Contrasts in Bandgap Closing and Formation Patterns of Axially-Vibrating Phononic Crystals

Abstract Bandgaps, or frequency ranges of forbidden wave propagation, are a hallmark of phononic crystals (PnCs). Unlike their lattice counterparts, PnCs taking the form of continuous structures exhibit an infinite number of bandgaps of varying location, bandwidth, and distribution along the frequency spectrum. While these bandgaps are commonly predicted from benchmark tools such as the Bloch-wave theory, the conditions that dictate the patterns associated with bandgap symmetry, attenuation, or even closing in multi-bandgap PnCs remain an enigma. In this work, we establish these patterns in one-dimensional rods undergoing longitudinal motion via a canonical transfer-matrix-based approach. In doing so, we connect the conditions governing bandgap formation and closing to their physical origins in the context of the Bragg condition (for infinite media) and natural resonances (for finite counterparts). The developed framework uniquely characterizes individual bandgaps within a larger dispersion spectrum regardless of their parity (i.e., odd versus even bandgaps) or location (low versus high-frequency), by exploiting dimensionless constants of the PnC unit cell which quantify the different contrasts between its constitutive layers. These developments are detailed for a bi-layered PnC and then generalized for a PnC of any number of layers by increasing the model complexity. We envision this mathematical development to be a future standard for the realization of hierarchically structured PnCs with prescribed and finely tailored bandgap profiles.

Gas–Liquid Chemical Reactions with Nanosecond Pulses: Role of Frequency and Pulse Delivery Modes

Gas–Liquid Chemical Reactions with Nanosecond Pulses: Role of Frequency and Pulse Delivery Modes

The role of purity and frequency in the classification of perimenstrual headache

BackgroundAmong all menstruation-associated headaches, only menstrual migraine has classification criteria in the International Classification of Headache Disorders 3rd edition (ICHD-3). Other menstruation-associated headaches are not generally described. The ICHD-3 classifies menstrual migraine according to headache type, timing(on days -2 to +3 of menstruation), frequency (whether headache occurs in at least two out of three menstrual cycles), and purity(whether headache occurs at other times of the menstrual cycle), and provides a reference for research on menstruation-associated headache. However, the role of frequency and purity in the classification of menstruation- associated headache is not clear Moreover, the potential risk factors for high-frequency and pure headaches have not been explored.MethodsThe study was a secondary analysis of an epidemiological survey on menstrual migraine among nurses. Among nurses who had a headache on days -2 to +3 of menstruation, headache frequency, purity, and type were described. High-frequency vs. low-frequency and pure vs. impure headache were compared according to headache features, demographics, occupation-related factors, menstruation-related factors, and lifestyle factors.ResultsOf all respondents, 254(18.3%) nurses who had headaches on days -2 to +3 of menstruation were included in the study. In the 254 nurses with perimenstrual headache, the proportions of migraine, tension type headache (TTH), high-frequency headache, and pure headache were 24.4%, 26.4%, 39.0%, and 42.1%, respectively. High-frequency and impure perimenstrual headache was more severe and similar to migraine. High-frequency headache was associated with more perimenstrual extremity swelling and generalized pain. Other variables were not significantly different between the groups.ConclusionsHeadache except for menstrual migraine accounts for a certain proportion of menstruation-associated headache and should not be ignored in research. Headache frequency and purity are related to headache type and should be equally considered in the classification of menstruation- associated headache. Perimenstrual extremity swelling and generalized pain are potential indicators of high-frequency perimenstrual headache.Trial registrationChiCTR2200056429

Élaboration d’une liste de vocabulaire dans un contexte FLE

In this article, we discuss the elaboration and use of vocabulary lists aimed for learners of French as a for-eign language. These lists are commonly based on corpora, which, in the ideal case, are representative, relevant and large. As for the English language, this kind of corpora has been available for a long time (e.g. the COCA and the BNC). Vocabulary lists, which are often used in learning contexts, have been based on these corpora. The situation is, however, less favorable when it comes to the French language, with fewer corpora meeting the mentioned criteria, and, thus, fewer possibilities to create vocabulary lists that are useful for learners. In this contribution, we present work that has been done in order to create a vocabulary list, Riksprovsordlistan, containing about 4,000 words and used at all Swedish universities. The discussion focuses on methodological challenges such as choice of counting unit – lemma vs. word family –, the role of frequency, thematic vocabulary, as well as characteristics of written vs. spoken corpora.

The role of frequency in language acquisition: input-output relationship

Children acquire the language system very fast and rather easily due to their sensitivity to lexical and grammatical structures and their distribution. Additionally, a stable distribution of linguistic structures in the input could help children to recognize these structures. We are aware of the fact that in many languages children start with nouns followed by verbs, therefore the distribution of the main parts of speech could signal important information about the syntactic structure of the early child speech.&#x0D; The primary aim of this study is to investigate the frequency distribution of parts of speech in child speech and input in Lithuanian. The analysis focuses on nouns, verbs, adjectives, adverbs, and pronouns, as these are the main elements constructing the syntactic relations of the utterance. The Lithuanian corpora have been studied that included the data of two children of different sex and their input. The main findings come from the analysis of the data of approximately one year (from the age of 1;7 to 2;8) and demonstrate an interesting result: a high degree of stability in the distribution of the target categories in the input data and a close correlation between input and output in later stages of children’s language development.

The Role of Frequency and Duty Cycle on the Gate Reliability of p-GaN HEMTs

In this letter, we present an extensive analysis on the role of both switching frequency (ranging from 100 kHz to 1 MHz) and duty cycle (from 10% to 90%) on the time-dependent gate breakdown of high electron mobility transistors (HEMTs) with Schottky metal to p-GaN gate. More specifically, results show how the gate lifetime of GaN HEMTs increases by reducing the frequency and the duty cycle of the stressing gate signal (VG). Such behavior is ascribed to the OFF-time, which is responsible to alter the electrostatic potential in the p-GaN layer during the rising phases of VG (from OFF- to ON-state). Findings of this analysis are useful both for further technology improvement and for GaN-based power circuit designers.

Parametric Study of Pulsed Field Ablation With Biphasic Waveforms in an In Vivo Heart Model: The Role of Frequency.

Pulsed field ablation (PFA) is a novel nonthermal cardiac ablation technology based on irreversible electroporation. Unfortunately, the characteristics of the electric field waveforms used in clinical and experimental PFA are not typically reported. This study examines the effect of the frequency of biphasic waveforms and compares biphasic to monophasic waveforms. A total of 29 Sprague-Dawley rats were treated with PFA using an epicardial monopolar electrode. Biphasic waveforms with three different frequencies, 90, 260, and 450 kHz (10 bursts of 100 µs duration at 500 V or 800 V) and monophasic waveforms (10 pulses of 100 µs duration at 500 V) were studied. Collateral neuromuscular stimulation and temperature increase in the point of application were directly measured. Lesion formation was assessed 3 weeks after treatment by histopathologic analysis. Computer simulations were used to estimate the electric field lethal threshold for each condition. A previous in vitro study was performed to draw a complete characterization of the studied dependencies. Morphometric analysis demonstrated a significant association between chronic lesion size and waveform characteristics. For the same voltage level, monophasic waveforms yielded the largest lesions compared with any of the biphasic protocols (P<0.05). Increasing PFA frequency was associated with reduced neuromuscular stimulation but also with reduced ablation efficacy. Maximum absolute temperature increase recorded along a complete treatment was 3 °C. Vascular structures inside the lesions were preserved for all conditions. Computer simulation-based analysis showed that waveform frequency had a graded effect on the lethal electric field threshold, with threshold of 600 V/cm for monophasic waveforms versus 2000 V/cm for biphasic waveforms with a frequency of 450 kHz. Frequency is a major determinant of efficacy in biphasic PFA. Our results highlight the critical need of disclosing waveform characteristics when reporting the results of different PFA systems.

Extraction from NP, frequency, and minimalist gradient harmonic grammar

AbstractExtraction of a PP from an NP in German is possible only if the head noun and the governing verb together form a natural predicate. We show that this corresponds to collocational frequency of the verb-noun combinations in corpora, based on the metric of ΔP. From this we conclude that frequency should be conceived of as a language-external grammatical building block that can directly interact with language-internal grammatical building blocks (like triggers for movement and economy constraints blocking movement) in excitatory and inhibitory ways. Integrating frequency directly into the syntax is not an option in most current grammatical theories. However, things are different inGradient Harmonic Grammar, a version of Optimality Theory where linguistic objects of various kinds can be assignedstrengthin the form of numerical values (weights). We show that by combining aMinimalistapproach to syntactic derivations with a Gradient Harmonic Grammar approach of constraint evaluation, the role of frequency in licensing extraction from PP in German can be integrated straightforwardly, the only additional prerequisite being that (verb-noun)dependenciesqualify as linguistic objects that can be assigned strength (based on their frequency).

The role of frequency in the acquisition of structured variation: The case of Basque ergativity

Aims and objectives: This study examines the extent to which new speakers use the Basque ergative case marking ( –k) in the nominal inflection. I specifically ask whether frequency-based factors (language use and lexical frequency) play a role in its use by also considering speakers’ self-claimed Basque identities. Design/methodology/approach: The spontaneous speech of 39 Basque–Spanish bilinguals was collected by means of sociolinguistic interviews. Participants were self-stratified according to categories of Basque speakerhood ( euskaldunberri “new speaker”; euskaldun “Basque speaker”; euskaldunzahar “native speaker”). We also considered their proficiency, language use, and sex. Data and analysis: In total, 2,755 tokens were extracted for the presence/absence of ergative –k and coded for the following four linguistic factors: verb type, animacy person and number, phonological context, and type of NP. Lexical frequency was operationalized in terms of overall token frequency of lexical verb. Data were analyzed using mixed-effects models in R. Findings and conclusions: Results indicate that despite higher incidence of ergative omissions among new speakers, they show (1) consistent mastery of core internal constraints (verb type, phonological context) and (2) gradual structuring based on lexical frequency effects. These omissions occur in pragmatically structured conditions (topic shift, emphasis, and introducing self in narrative) alongside extensions of –k to unaccusative contexts (focus and topicalization). No independent effects of language use were found. Originality: This study is the first to examine of Basque ergativity among adult Basque speakers, taking also into account discourse factors, lexical frequency, and speakers’ social identities and proficiencies. Significance and implications: First, the mediating effects of lexical frequency are indicative that that sociolinguistic variation is acquired in a piece-meal fashion and that such patterns emerge from discourse as they are used in context. Second, it is argued that the new speakers’ kind of social practices hold key in explaining the reallocation of linguistic constraints in their variable production.

Register impacts perceptual consonance through roughness and sharpness

The perception of consonance and dissonance in intervals and chords is influenced by psychoacoustic and cultural factors. Past research has provided conflicting observations about the role of frequency in assessing musical consonance that may stem from comparisons of limited frequency bands without much theorizing or modeling. Here we examine the effect of register on perceptual consonance of chords. Based on two acoustic principles, we predict a decrease in consonance at low frequencies (roughness) and a decrease of consonance at high frequencies (sharpness). Due to these two separate principles, we hypothesize that frequency will have a curvilinear impact on consonance. A selection of tetrads varying in consonance were presented in seven registers spanning 30 to 2600 Hz. Fifty-five participants rated the stimuli in an online experiment. The effect of register on consonance ratings was clear and largely according to the predictions; The low registers impacted consonance negatively and the highest two registers also received significantly lower consonance ratings than the middle registers. The impact of register on consonance could be accurately described with a cubic relationship. Overall, the influence of roughness was more pronounced on consonance ratings than sharpness. Together, these findings clarify previous empirical efforts to model the effect of frequency on consonance through basic acoustic principles. They further suggest that a credible account of consonance and dissonance in music needs to incorporate register.

How Cognition came into being

Jacques Mehler and I started Cognition, to break the grip of empiricist associationist behaviorism and stultifying style requirements on scientific discourse, and to liberate Cognitive Psychology's contributions to social issues. The journal provided opportunities for upcoming generations to expand Cognitive Psychology, publishing new concepts unhindered by established topics and standard formats. As the journal matured, Jacques kept. it fresh for 4 decades, seeking young scientists, novel ideas, and elegant writing, as it midwifed the emergence from Reductionist Behaviorism through Cognitive Psychology to rationalist Cognitive Science. The journal now has opportunities to nurture further progress in the future of Cognitive Science. I speculate that the field will keep associationist processes but integrate them with a new kind of non-reductionist theory that eschews detailed predictions, and which which interprets the brain as an enactor of thought, but not its structural cause. Ideally it will provide a set of constraints on the action of brain and mind that subsume and explain behavioral regularities, the role of frequency, how the brain externalizes those constraints and how the externalization processes emerge developmentally as a function of innate factors, structures unique to the mind and brain, experience and natural law.

Iconicity and Diachronic Language Change.

Iconicity, the resemblance between the form of a word and its meaning, has effects on behavior in both communicative symbol development and language learning experiments. These results have invited speculation about iconicity being a key feature of the origins of language, yet the presence of iconicity in natural languages seems limited. In a diachronic study of language change, we investigated the extent to which iconicity is a stable property of vocabulary, alongside previously investigated psycholinguistic predictors of change. Analyzing 784 English words with data on their historical forms, we found that stable words are higher in iconicity, longer in length, and earlier acquired during development, but that the role of frequency and grammatical category may be less important than previously suggested. Iconicity is revealed as a feature of ultra-conserved words and potentially also as a property of vocabulary early in the history of language origins.

Limitations on the role of frequency in L2 acquisition

abstractIn the context of theories of statistical learning, frequency of encounter is viewed as a major driving force in L2 acquisition. The present paper challenges this position with respect to core components at the level of language competence which relate to language-specific patterns in cognitive construal. Empirical evidence from very advanced L2 speakers (L1 French, L2 English and L2 German) shows that forms and constructions which are highly frequent in the target languages in the expression of motion events are not used in a target-like form by L2 speakers. The study shows how the basis for language use which is not target-like lies at the level of event construal: conceptual frames, which are language-specific and are deeply anchored in the course of L1 acquisition, drive allocation of attention and the extraction of forms in L2 acquisition. Findings in the domain of spatial cognition show that motion event frames based on the L1 take precedence over frequency of occurrence of forms in the target language as a factor in L2 use.

Socioeconomic status and medication adherence among youth with asthma: the mediating role of frequency of children’s daily routines

Objective The current research aims to examine a potential explanation for SES disparities in youth medication adherence: the frequency of children’s daily routines. Design In a cross-sectional sample of 194 youth with asthma (112 boys and 82 girls; average age = 12.8 years old) and their primary caregivers primarily from the Detroit metropolitan area, caregivers reported their SES and the frequency of their children’s daily routines during the first laboratory visit. At a follow-up visit, caregivers and their children completed the Family Asthma Management System Scale (FAMSS), a well-validated, semi-structured interview that assess children’s degree of adherence to prescribed medications. Main Outcome Measures Children’s daily routines were measured with the Child Routines Inventory while children’s medication adherence was measured with the FAMSS. Results Mediation analyses revealed that the association between subjective (but not objective) SES and medication adherence was partially mediated by the frequency of children’s daily routines. Conclusion These results suggest that the frequency of children’s daily routines is an important factor linking SES and medication adherence, a finding with important implications for improving health outcomes and reducing health disparities between low SES children and their high SES counterparts.

What Is the Role of Frequency on Neural Activation in Tonic Stimulation in SCS Therapy? A Computational Study on Sensory Aβ Nerve Fibers

The investigation of the effect of the stimulation parameters by computational modeling helps to understand the electrical response of specific neural elements in Spinal Cord Stimulation (SCS) therapy for chronic pain treatment. While the effect of the amplitude, the pulse width, and the electrode configuration on neural activation has been widely studied and is well-established in tonic stimulation, how frequency influences neural activation remains unclear. Thus, the aim of this work is to study the effect of frequency on the electrical response of sensory Aβ neurons in tonic stimulation. Our approach consisted of the development of a new nerve fiber model from the combination of two previous models used in SCS modeling (the Wesselink-Holsheimer-Boom model and the Richardson-McIntyre-Grill model B). We simulate the action potential and the gates probabilities evolution of a 12.8 μm fiber diameter at different pulse frequencies (50, 350, 600, 800, and 1000 Hz). We also simulated the firing rate of two nerve fiber diameters (5.7 and 12.8 μm) in function of pulse frequency (from 1 to 1400 Hz) at different pulse widths (100, 300, and 500 μs). In the range of 2-1000 Hz, the firing rate of a 12.8 μm-diameter nerve fiber can be maximized by utilizing a 350 Hz, 300 μs-stimulus. Frequencies above 350 Hz reduce half to one-third the firing rate, and 1000 Hz-stimulus overrides the electrical activity of the sensory nerve fiber. Small fibers (5.7 μm-diameter) present lower firing rate values than large fibers ( 12.8 μm-diameter). High values of pulse width decrease the firing rate of the nerve fibers as well as the range of frequencies that could be used to stimulate. According to the results, the frequency could have a considerable implication on the modulation of the firing rate of a nerve fiber. Thus, the frequency could play an important role to select and increase the activity of specific neural elements of the spinal cord in SCS therapy.

Electromagnetic Fields and Calcium Signaling by the Voltage Dependent Anion Channel

Electromagnetic fields (EMFs) can interact with biological tissues exerting positive as well as negative effects on cell viability, but the underlying sensing and signaling mechanisms are largely unknown. So far in excitable cells EMF exposure was postulated to cause Ca2+ influx through voltage-dependent Ca channels (VDCC) leading to cell activation and an antioxidant response. Upon further activation oxidative stress causing DNA damage or cell death may follow. Here we report collected evidence from literature that voltage dependent anion channels (VDAC) located not only in the outer microsomal membrane but also in the cytoplasmic membrane convert to Ca2+ conducting channels of varying capacities upon subtle changes of the applied EMF even in non-excitable cells like erythrocytes. Thus, VDAC can be targeted by external EMF in both types of membranes to release Ca2+ into the cytosol. The role of frequency, pulse modulation or polarization remains to be investigated in suitable cellular models. VDACs are associated with several other proteins, among which the 18 kDa translocator (TSPO) is of specific interest since it was characterized as the central benzodiazepine receptor in neurons. Exhibiting structural similarities with magnetoreceptors we propose that TSPO could sense the magnetic component of the EMF and thus together with VDAC could trigger physiological as well as pathological cellular responses. Pulsed EMFs in the frequency range of the brain-wave communication network may explain psychic disturbances of electromagnetic hypersensitive persons. An important support is provided from human psychology that states deficits like insomnia, anxiety or depression can be treated with diazepines that indicates apparent connections between the TSPO/VDAC complex and organismic responses to EMF.

A Review on the Role of Token Frequency in the Acquisition of Argument Structures

The role of frequency in second language acquisition has become an important focus among second language acquisition researchers. Argument structure, as one of the core topics of verbs, has always been the focus of academic attention. Frequency has a certain influence on second language construction acquisition, and the corresponding research is abundant. This paper reviews the research on the acquisition of argument structure construction with token frequency and its enlightenment to teaching, and puts forward some suggestions for future research.