The Effects of Background Noise on Dichotic Listening to Consonant-Vowel Syllables

Science.gov (United States)

Sequeira, Sarah Dos Santos; Specht, Karsten; Hamalainen, Heikki; Hugdahl, Kenneth

2008-01-01

Lateralization of verbal processing is frequently studied with the dichotic listening technique, yielding a so called right ear advantage (REA) to consonant-vowel (CV) syllables. However, little is known about how background noise affects the REA. To address this issue, we presented CV-syllables either in silence or with traffic background noise…

Aerodynamic Characteristics of Syllable and Sentence Productions in Normal Speakers.

Science.gov (United States)

Thiel, Cedric; Yang, Jin; Crawley, Brianna; Krishna, Priya; Murry, Thomas

2018-01-08

Aerodynamic measures of subglottic air pressure (Ps) and airflow rate (AFR) are used to select behavioral voice therapy versus surgical treatment for voice disorders. However, these measures are usually taken during a series of syllables, which differs from conversational speech. Repeated syllables do not share the variation found in even simple sentences, and patients may use their best rather than typical voice unless specifically instructed otherwise. This study examined the potential differences in estimated Ps and AFR in syllable and sentence production and their effects on a measure of vocal efficiency in normal speakers. Prospective study. Measures of estimated Ps, AFR, and aerodynamic vocal efficiency (AVE) were obtained from 19 female and four male speakers ages 22-44 years with no history of voice disorders. Subjects repeated a series of /pa/ syllables and a sentence at comfortable effort level into a face mask with a pressure-sensing tube between the lips. AVE varies as a function of the speech material in normal subjects. Ps measures were significantly higher for the sentence-production samples than for the syllable-production samples. AFR was higher during sentence production than syllable production, but the difference was not statistically significant. AVE values were significantly higher for syllable versus sentence productions. The results suggest that subjects increase Ps and AFR in sentence compared with syllable production. Speaking task is a critical factor when considering measures of AVE, and this preliminary study provides a basis for further aerodynamic studies of patient populations. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Enhanced Passive and Active Processing of Syllables in Musician Children

Science.gov (United States)

Chobert, Julie; Marie, Celine; Francois, Clement; Schon, Daniele; Besson, Mireille

2011-01-01

The aim of this study was to examine the influence of musical expertise in 9-year-old children on passive (as reflected by MMN) and active (as reflected by discrimination accuracy) processing of speech sounds. Musician and nonmusician children were presented with a sequence of syllables that included standards and deviants in vowel frequency,…

The role of syllables in sign language production.

Science.gov (United States)

Baus, Cristina; Gutiérrez, Eva; Carreiras, Manuel

2014-01-01

The aim of the present study was to investigate the functional role of syllables in sign language and how the different phonological combinations influence sign production. Moreover, the influence of age of acquisition was evaluated. Deaf signers (native and non-native) of Catalan Signed Language (LSC) were asked in a picture-sign interference task to sign picture names while ignoring distractor-signs with which they shared two phonological parameters (out of three of the main sign parameters: Location, Movement, and Handshape). The results revealed a different impact of the three phonological combinations. While no effect was observed for the phonological combination Handshape-Location, the combination Handshape-Movement slowed down signing latencies, but only in the non-native group. A facilitatory effect was observed for both groups when pictures and distractors shared Location-Movement. Importantly, linguistic models have considered this phonological combination to be a privileged unit in the composition of signs, as syllables are in spoken languages. Thus, our results support the functional role of syllable units during phonological articulation in sign language production.

Lingual Kinematics during Rapid Syllable Repetition in Parkinson's Disease

Science.gov (United States)

Wong, Min Ney; Murdoch, Bruce E.; Whelan, Brooke-Mai

2012-01-01

Background: Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). Aims: To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric…

[A new syllable text for evaluating near vision].

Science.gov (United States)

Kolling, G H; Höltzcke, P

1995-02-01

When visual acuity for distance is tested correct recognition of (as an example) 6 of 10 Landolt-rings is required. On the other hand, it is very difficult to define visual acuity exactly with reading cards, the result will also depend on the patient's reading ability. The new near vision test consists of 10 syllables with two letters being calibrated according to DIN 58,220 (part 2 A1-correlation of optotypes) by Rassow et al. [11]. The patient is required to recognize 6 syllables out of 10 correctly. To test crowding phenomena the syllables are connected by a letterlike symbol. In 18 patients suffering from squint amblyopia and in 18 patients suffering from anisometropic amblyopia visual acuity with Oculus reading cards and with the new near vision test was identical. The crowding syllables test yielded a visual acuity comparable to that determined with the C test according to Haase/Hohmann [6]. The new near vision test makes it possible to examine visual acuity for reading with syllables as exactly as for single optotypes using Landolt-rings. In both cases, 6 of 10 answers have to be correct. Additionally, reading time for one syllable can be restricted to one second when patients with nystagmus are being tested.

Effects of measurement method and transcript availability on inexperienced raters' stuttering frequency scores.

Science.gov (United States)

Chakraborty, Nalanda; Logan, Kenneth J

To examine the effects of measurement method and transcript availability on the accuracy, reliability, and efficiency of inexperienced raters' stuttering frequency measurements. 44 adults, all inexperienced at evaluating stuttered speech, underwent 20 min of preliminary training in stuttering measurement and then analyzed a series of sentences, with and without access to transcripts of sentence stimuli, using either a syllable-based analysis (SBA) or an utterance-based analysis (UBA). Participants' analyses were compared between groups and to a composite analysis from two experienced evaluators. Stuttering frequency scores from the SBA and UBA groups differed significantly from the experienced evaluators' scores; however, UBA scores were significantly closer to the experienced evaluators' scores and were completed significantly faster than the SBA scores. Transcript availability facilitated scoring accuracy and efficiency in both groups. The internal reliability of stuttering frequency scores was acceptable for the SBA and UBA groups; however, the SBA group demonstrated only modest point-by-point agreement with ratings from the experienced evaluators. Given its accuracy and efficiency advantages over syllable-based analysis, utterance-based fluency analysis appears to be an appropriate context for introducing stuttering frequency measurement to raters who have limited experience in stuttering measurement. To address accuracy gaps between experienced and inexperienced raters, however, use of either analysis must be supplemented with training activities that expose inexperienced raters to the decision-making processes used by experienced raters when identifying stuttered syllables. Copyright © 2018 Elsevier Inc. All rights reserved.

Temporal order processing of syllables in the left parietal lobe.

Science.gov (United States)

Moser, Dana; Baker, Julie M; Sanchez, Carmen E; Rorden, Chris; Fridriksson, Julius

2009-10-07

Speech processing requires the temporal parsing of syllable order. Individuals suffering from posterior left hemisphere brain injury often exhibit temporal processing deficits as well as language deficits. Although the right posterior inferior parietal lobe has been implicated in temporal order judgments (TOJs) of visual information, there is limited evidence to support the role of the left inferior parietal lobe (IPL) in processing syllable order. The purpose of this study was to examine whether the left inferior parietal lobe is recruited during temporal order judgments of speech stimuli. Functional magnetic resonance imaging data were collected on 14 normal participants while they completed the following forced-choice tasks: (1) syllable order of multisyllabic pseudowords, (2) syllable identification of single syllables, and (3) gender identification of both multisyllabic and monosyllabic speech stimuli. Results revealed increased neural recruitment in the left inferior parietal lobe when participants made judgments about syllable order compared with both syllable identification and gender identification. These findings suggest that the left inferior parietal lobe plays an important role in processing syllable order and support the hypothesized role of this region as an interface between auditory speech and the articulatory code. Furthermore, a breakdown in this interface may explain some components of the speech deficits observed after posterior damage to the left hemisphere.

For a Psycholinguistic Model of Handwriting Production: Testing the Syllable-Bigram Controversy

Science.gov (United States)

Kandel, Sonia; Peereman, Ronald; Grosjacques, Geraldine; Fayol, Michel

2011-01-01

This study examined the theoretical controversy on the impact of syllables and bigrams in handwriting production. French children and adults wrote words on a digitizer so that we could collect data on the local, online processing of handwriting production. The words differed in the position of the lowest frequency bigram. In one condition, it…

Verbal cues effectively orient children's auditory attention in a CV-syllable dichotic listening paradigm.

Science.gov (United States)

Phélip, Marion; Donnot, Julien; Vauclair, Jacques

2015-12-18

In their groundbreaking work featuring verbal dichotic listening tasks, Mondor and Bryden showed that tone cues do not enhance children's attentional orienting, in contrast to adults. The magnitude of the children's right-ear advantage was not attenuated when their attention was directed to the left ear. Verbal cues did, however, appear to favour the orientation of attention at around 10 years, although stimulus-onset asynchronies (SOAs), which ranged between 450 and 750 ms, were not rigorously controlled. The aim of our study was therefore to investigate the role of both types of cues in a typical CV-syllable dichotic listening task administered to 8- to 10-year-olds, applying a protocol as similar as possible to that used by Mondor and Bryden, but controlling for SOA as well as for cued ear. Results confirmed that verbal cues are more effective than tone cues in orienting children's attention. However, in contrast to adults, no effect of SOA was observed. We discuss the relative difficulty young children have processing CV syllables, as well as the role of top-down processes in attentional orienting abilities.

Rhythmic speech and stuttering reduction in a syllable-timed language.

Science.gov (United States)

Law, Thomas; Packman, Ann; Onslow, Mark; To, Carol K-S; Tong, Michael C-F; Lee, Kathy Y-S

2018-06-06

Speaking rhythmically, also known as syllable-timed speech (STS), has been known for centuries to be a fluency-inducing condition for people who stutter. Cantonese is a tonal syllable-timed language and it has been shown that, of all languages, Cantonese is the most rhythmic (Mok, 2009). However, it is not known if STS reduces stuttering in Cantonese as it does in English. This is the first study to investigate the effects of STS on stuttering in a syllable-timed language. Nineteen native Cantonese-speaking adults who stutter were engaged in conversational tasks in Cantonese under two conditions: one in their usual speaking style and one using STS. The speakers' percentage syllables stuttered (%SS) and speech rhythmicity were rated. The rhythmicity ratings were used to estimate the extent to which speakers were using STS in the syllable-timed condition. Results revealed a statistically significant reduction in %SS in the STS condition; however, this reduction was not as large as in previous studies in other languages and the amount of stuttering reduction varied across speakers. The rhythmicity ratings showed that some speakers were perceived to be speaking more rhythmically than others and that the perceived rhythmicity correlated positively with reductions in stuttering. The findings were unexpected, as it was anticipated that speakers of a highly rhythmic language such as Cantonese would find STS easy to use and that the consequent reductions in stuttering would be great, even greater perhaps than in a stress-timed language such as English. The theoretical and clinical implications of the findings are discussed.

Syllable Durations of Preword and Early Word Vocalizations.

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Robb, Michael P.; Saxman, John H.

1990-01-01

The continuity in development of syllable duration patterns was examined in seven young children as they progressed from preword to multiword periods of vocalization development. Results revealed no systematic increase or decrease in the duration of bisyllables produced by the children as a group, whereas lengthening of final syllables was…

Phonetic Accounts of Timed Responses in Syllable Monitoring Experiments

NARCIS (Netherlands)

Rietveld, A.C.M.; Schiller, N.O.; Caspers, J.; Chen, Y.; Heeren, W.; Pacilly, J.; Schiller, N.O.; Zanten, E. van

2014-01-01

This paper reports a syllable monitoring experiment that examines the role of segmental phonetic information in Dutch. Participants were presented with lists of spoken words and were required to detect auditorily specified targets that matched or did not match the initial syllable of the spoken

Syllable reduction and articulation rates in Danish, Norwegian and Swedish

NARCIS (Netherlands)

Hilton, N.H.; Schüppert, Anja; Gooskens, C.S.

2011-01-01

This investigation compares articulation rates of phonological and phonetic syllables in Norwegian, Swedish and Danish to investigate differences in degrees of syllable deletion (reduction) among these three languages. For the investigation two sets of data are used: one consisting of recorded

The Word Frequency Effect on Second Language Vocabulary Learning

Science.gov (United States)

Koirala, Cesar

2015-01-01

This study examines several linguistic factors as possible contributors to perceived word difficulty in second language learners in an experimental setting. The investigated factors include: (1) frequency of word usage in the first language, (2) word length, (3) number of syllables in a word, and (4) number of consonant clusters in a word. Word…

Relations Among Detection of Syllable Stress, Speech Abnormalities, and Communicative Ability in Adults With Autism Spectrum Disorders.

Science.gov (United States)

Kargas, Niko; López, Beatriz; Morris, Paul; Reddy, Vasudevi

2016-04-01

To date, the literature on perception of affective, pragmatic, and grammatical prosody abilities in autism spectrum disorders (ASD) has been sparse and contradictory. It is interesting to note that the primary perception of syllable stress within the word structure, which is crucial for all prosody functions, remains relatively unexplored in ASD. Thus, in the current study, we explored syllable stress perception sensitivity and its relationship to speech production abnormalities and communicative ability in adults with ASD. A same-different syllable stress perception task using pairs of identical 4-syllable words was delivered to 42 adults with/without high-functioning ASD, matched for age, to investigate primary speech perception ability in ASD. Speech production and communicative ability in ASD was measured using the Autism Diagnostic Observation Schedule (Lord et al., 2000). As predicted, the results showed that adults with ASD were less sensitive in making judgments about syllable stress relative to controls. Also, partial correlations revealed a key association of speech production abnormalities with stress perception sensitivity, rather than communicative ability. Our findings provide empirical evidence for deficits on primary syllable stress perception in ASD and its role on sociocommunicative difficulties. This information could facilitate the development of effective interventions for speech and language therapy and social communication.

A study of syllable codas in South African Sign Language

African Journals Online (AJOL)

Kate H

A South African Sign Language Dictionary for Families with Young Deaf Children (SLED 2006) was used with permission ... Figure 1: Syllable structure of a CVC syllable in the word “bed”. In spoken languages .... often than not, there is a societal emphasis on 'fixing' a child's deafness and attempting to teach deaf children to ...

A Note on Ko-Type O-Ending Syllables in Old Japanese

Science.gov (United States)

Unger, J. Marshall

1975-01-01

Further evidence is offered to support the argument that ko-type o-ending syllables may have been secondary in nature in Old Japanese. Pre-Old Japanese indicates the */uwa/ sequence was manifested as /uwe/ and /uwu/ endings of o-ending syllable verbs. (SCC)

Abstract The syllable is very vital in phonological analysis. This is ...

African Journals Online (AJOL)

Tracie1

forces the sequence of words in syllables to agree with the acceptable order of any given language. ithin the broader ... structure constraints within the purview of universal grammar without the need to generate ... syllables to form words triggers phonological processes, and also, the phonotactic constraints of languages ...

A mechanism for frequency modulation in songbirds shared with humans.

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Amador, Ana; Margoliash, Daniel

2013-07-03

In most animals that vocalize, control of fundamental frequency is a key element for effective communication. In humans, subglottal pressure controls vocal intensity but also influences fundamental frequency during phonation. Given the underlying similarities in the biomechanical mechanisms of vocalization in humans and songbirds, songbirds offer an attractive opportunity to study frequency modulation by pressure. Here, we present a novel technique for dynamic control of subsyringeal pressure in zebra finches. By regulating the opening of a custom-built fast valve connected to the air sac system, we achieved partial or total silencing of specific syllables, and could modify syllabic acoustics through more complex manipulations of air sac pressure. We also observed that more nuanced pressure variations over a limited interval during production of a syllable concomitantly affected the frequency of that syllable segment. These results can be explained in terms of a mathematical model for phonation that incorporates a nonlinear description for the vocal source capable of generating the observed frequency modulations induced by pressure variations. We conclude that the observed interaction between pressure and frequency was a feature of the source, not a result of feedback control. Our results indicate that, beyond regulating phonation or its absence, regulation of pressure is important for control of fundamental frequencies of vocalizations. Thus, although there are separate brainstem pathways for syringeal and respiratory control of song production, both can affect airflow and frequency. We hypothesize that the control of pressure and frequency is combined holistically at higher levels of the vocalization pathways.

The Basis of the Syllable Hierarchy: Articulatory Pressures or Universal Phonological Constraints?

Science.gov (United States)

Zhao, Xu; Berent, Iris

2018-01-01

Across languages, certain syllable types are systematically preferred to others (e.g., "blif" ? "bnif" ? "bdif" ? "lbif" where ? indicates a preference). Previous research has shown that these preferences are active in the brains of individual speakers, they are evident even when none of these syllable types…

Pattern of language-related potential maps in cluster and noncluster initial consonants in consonant-vowel (CV syllables

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Naiphinich Kotchabhakdi

2006-09-01

Full Text Available Mismatch negativity (MMN was used to investigate the processing of cluster and noncluster initial consonants in consonant vowel syllables in the human brain. The MMN was elicited by either syllable with cluster or noncluster initial consonant, phonetic contrasts being identical in both syllables. Compared to the noncluster consonant, the cluster consonant elicited a more prominent MMN. The MMN to the cluster consonant occurred later than that of the noncluster consonant. The topography of the mismatch responses showed clear left-hemispheric laterality in both syllables. However, the syllable with an initial noncluster consonant stimulus produced MMN maximum over the middle temporal gyrus, whereas maximum of the MMN activated by the syllable with initial cluster consonant was observed over the superior temporal gyrus. We suggest that the MMN component in consonant-vowel syllables is more sensitive to cluster compared to noncluster initial consonants. Spatial and temporal features of the cluster consonant indicate delayed activation of left-lateralized perisylvian cell assemblies that function as cortical memory traces of cluster initial consonant in consonant-vowel syllables.

THE ACQUISITION OF ENGLISH SYLLABLE TIMING BY NATIVE SPANISH SPEAKERS LEARNERS OF ENGLISH. AN EMPIRICAL STUDY'

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Francisco Gutierrez Diez

2001-06-01

Full Text Available In this article we present part of the results of an empirical research on contrastive rhythm (English-Spanish. Of the several points dealt with in such a research (syllable compression, foot timing, syllable timing and isochrony of rhythmic units, we refer here to syllable duration in English and Spanish as well as the leaming of syllable duration by a group of advanced leamers of English whose first language is Spanish. Regarding the issue of syllable timing, a striking result is the equal duration of unstressed syllables in both languages, which challenges an opposite view underlying a teaching practice common among Spanish teachers of English to Spanish learners of that language. As for the interlanguage of the group of Spanish leamers of English, we comment on the presence of an interference error represented by a stressed/unstressed durational ratio mid way between the ratios for Spanish and English; we have also detected a developmental error related to the tempo employed by the leamers in their syllable timing, which is slower than the tempo produced by native speakers of English.

Rhyme and Syllable Recognition in Severe to Profound Hearing-Impaired Children

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MohammadReza Keihani

2003-09-01

Full Text Available Objective: A research was conducted to assess the phonological awareness in hearing-impaired children in comparison to normal children. In this context, we discussed about the ability of these children in identification of rhyme and word segmentation to syllables. Method and Material: The sample of this study is composed of 320 children, 160 normal & 160 hearing-impaired with a hearing-loss. Of over 70 dB, studying in the 1st t 4th grade of the primary schools in Tehran. They are divided into two groups at each level (20 girls & 20 boys. Results: 1 Hearing-impaired children's scores on test related to rhyme and syllable is lower as compared with normal children. 2 Hearing-impaired children are more potent on test of word segmentation to syllables in comparison to that related to rhyme, while normal children are more successful on test of word segmentation to syllables as compared with that related to rhyme. Discussion: Hearing is an important factor in phonological awareness. Formal education at special schools doesn't compensate for the hearing impairment as to development of the phonological awareness.

Polar-phase indices of perioral muscle reciprocity during syllable production in Parkinson's disease.

Science.gov (United States)

Chu, Shin Ying; Barlow, Steven M; Lee, Jaehoon; Wang, Jingyan

2017-12-01

This research characterised perioral muscle reciprocity and amplitude ratio in lower lip during bilabial syllable production [pa] at three rates to understand the neuromotor dynamics and scaling of motor speech patterns in individuals with Parkinson's disease (PD). Electromyographic (EMG) signals of the orbicularis oris superior [OOS], orbicularis oris inferior [OOI] and depressor labii inferioris [DLI] were recorded during syllable production and expressed as polar-phase notations. PD participants exhibited the general features of reciprocity between OOS, OOI and DLI muscles as reflected in the EMG during syllable production. The control group showed significantly higher integrated EMG amplitude ratio in the DLI:OOS muscle pairs than PD participants. No speech rate effects were found in EMG muscle reciprocity and amplitude magnitude across all muscle pairs. Similar patterns of muscle reciprocity in PD and controls suggest that corticomotoneuronal output to the facial nucleus and respective perioral muscles is relatively well-preserved in our cohort of mild idiopathic PD participants. Reduction of EMG amplitude ratio among PD participants is consistent with the putative reduction in the thalamocortical activation characteristic of this disease which limits motor cortex drive from generating appropriate commands which contributes to bradykinesia and hypokinesia of the orofacial mechanism.

F₀-based rhythm effects on the perception of local syllable prominence

DEFF Research Database (Denmark)

Niebuhr, Oliver

2009-01-01

of the global rhythmic context with regard to both the prominence and the F(0) patterns. Two conclusions were drawn on this basis. First, listeners use speech rhythm to predict the perceptual properties of syllables, which is in line with the guide function that speech rhythm is assumed to have in German...

Open Syllable Once Again. Endogenous or Exogenous?

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Raffaele Caldarelli

2013-02-01

Full Text Available After a brief reply to some critical remarks raised by Mario Enrietti in a paper published in “Studi Slavistici”, VI (2009, the Author tries to explain why Enrietti’s theory of an exogenous, namely Romance origin of the Slavic open syllable structure should be rejected.

Final Syllable Lengthening (FSL) in Infant Vocalizations.

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Nathani, Suneeti; Oller, D. Kimbrough; Cobo-Lewis, Alan B.

2003-01-01

Sought to verify research findings that suggest there may be a U-shaped developmental trajectory for final syllable lengthening (FSL). Attempted to determine whether vocal maturity and deafness influence FSL . Eight normally hearing infants and eight deaf infants were examined at three levels of prelinguistic vocal development. (Author/VWL)

Implicit Segmentation of a Stream of Syllables Based on Transitional Probabilities: An MEG Study

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Teinonen, Tuomas; Huotilainen, Minna

2012-01-01

Statistical segmentation of continuous speech, i.e., the ability to utilise transitional probabilities between syllables in order to detect word boundaries, is reflected in the brain's auditory event-related potentials (ERPs). The N1 and N400 ERP components are typically enhanced for word onsets compared to random syllables during active…

Automatic transcription of continuous speech into syllable-like units ...

Indian Academy of Sciences (India)

style HMM models are generated for each of the clusters during training. During testing .... manual segmentation at syllable-like units followed by isolated style recognition of continu- ous speech ..... obtaining demisyllabic reference patterns.

Impaired recovery of syllable repertoires after unilateral lesions of the HVC of male domesticated canaries.

NARCIS (Netherlands)

Halle, F; Gahr, M.; Kreutzer, M.

2003-01-01

Particular features of the song of adult male canaries such as a large syllable repertoire resulting in a great diversity of song phrases and special so-called 'complex' syllables enhance various features of female reproductive behaviour. These features are produced in a species or strain dependent

Quantitative Investigations in Hungarian Phonotactics and Syllable Structure

Science.gov (United States)

Grimes, Stephen M.

2010-01-01

This dissertation investigates statistical properties of segment collocation and syllable geometry of the Hungarian language. A corpus and dictionary based approach to studying language phonologies is outlined. In order to conduct research on Hungarian, a phonological lexicon was created by compiling existing dictionaries and corpora and using a…

Consonant and Syllable Structure Patterns in Childhood Apraxia of Speech: Developmental Change in Three Children

Science.gov (United States)

Jacks, Adam; Marquardt, Thomas P.; Davis, Barbara L.

2006-01-01

Changes in consonant and syllable-level error patterns of three children diagnosed with childhood apraxia of speech (CAS) were investigated in a 3-year longitudinal study. Spontaneous speech samples were analyzed to assess the accuracy of consonants and syllables. Consonant accuracy was low overall, with most frequent errors on middle- and…

Fluctuations in Unimanual Hand Preference in Infants Following the Onset of Duplicated Syllable Babbling.

Science.gov (United States)

Ramsay, Douglas S.

1985-01-01

Infants were tested for unimanual handedness at weekly intervals for a 14-week period beginning with the week of onset of duplicated syllable babbling. Group analyses indicating effects of sex and/or birth order on fluctuations and date review for individual infants suggested considerable variability across infants in occurrence and/or timing of…

Accounting for the 'CCV' Syllable Structure of Akan:

African Journals Online (AJOL)

Charles Marfo

heart of the phonology consists of a hierarchy of ranked and violable universal constraints therefore, it is argued that .... a separate involving /r/ and the consonant of the preceding syllable. In other words, it is assumed that /r/ became the bearer of the tone only because of the elision of the vowel that should have been before ...

This Whole World Is OM: Song, Soteriology, and the Emergence of the Sacred Syllable

OpenAIRE

Moore Gerety, Finnian McKean

2015-01-01

This study explores the emergence of OM, the Sanskrit mantra and critically ubiquitous "sacred syllable" of South Asian religions. Although OM has remained in active practice in recitation, ritual, and meditation for the last three thousand years, and its importance in Hindu, Buddhist, and Jain traditions is widely acknowledged, the syllable's early development has received little attention from scholars. Drawing on the oldest textual corpus in South Asia, the Vedas, I survey one thousand yea...

The Parsing Syllable Envelopes Test for Assessment of Amplitude Modulation Discrimination Skills in Children: Development, Normative Data, and Test-Retest Reliability Studies.

Science.gov (United States)

Cameron, Sharon; Chong-White, Nicky; Mealings, Kiri; Beechey, Tim; Dillon, Harvey; Young, Taegan

2018-02-01

Intensity peaks and valleys in the acoustic signal are salient cues to syllable structure, which is accepted to be a crucial early step in phonological processing. As such, the ability to detect low-rate (envelope) modulations in signal amplitude is essential to parse an incoming speech signal into smaller phonological units. The Parsing Syllable Envelopes (ParSE) test was developed to quantify the ability of children to recognize syllable boundaries using an amplitude modulation detection paradigm. The envelope of a 750-msec steady-state /a/ vowel is modulated into two or three pseudo-syllables using notches with modulation depths varying between 0% and 100% along an 11-step continuum. In an adaptive three-alternative forced-choice procedure, the participant identified whether one, two, or three pseudo-syllables were heard. Development of the ParSE stimuli and test protocols, and collection of normative and test-retest reliability data. Eleven adults (aged 23 yr 10 mo to 50 yr 9 mo, mean 32 yr 10 mo) and 134 typically developing, primary-school children (aged 6 yr 0 mo to 12 yr 4 mo, mean 9 yr 3 mo). There were 73 males and 72 females. Data were collected using a touchscreen computer. Psychometric functions (PFs) were automatically fit to individual data by the ParSE software. Performance was related to the modulation depth at which syllables can be detected with 88% accuracy (referred to as the upper boundary of the uncertainty region [UBUR]). A shallower PF slope reflected a greater level of uncertainty. Age effects were determined based on raw scores. z Scores were calculated to account for the effect of age on performance. Outliers, and individual data for which the confidence interval of the UBUR exceeded a maximum allowable value, were removed. Nonparametric tests were used as the data were skewed toward negative performance. Across participants, the performance criterion (UBUR) was met with a median modulation depth of 42%. The effect of age on the UBUR was

A Longitudinal Study of Handwriting Skills in Pre-Schoolers: The Acquisition of Syllable Oriented Programming Strategies

Science.gov (United States)

Soler Vilageliu, Olga; Kandel, Sonia

2012-01-01

Previous studies have shown the relevance of the syllable as a programming unit in handwriting production, both in adults and elementary school children. This longitudinal study focuses on the acquisition of writing skills in a group of preschoolers. It examines how and when the syllable structure of the word starts regulating motor programming in…

Imaging auditory representations of song and syllables in populations of sensorimotor neurons essential to vocal communication.

Science.gov (United States)

Peh, Wendy Y X; Roberts, Todd F; Mooney, Richard

2015-04-08

Vocal communication depends on the coordinated activity of sensorimotor neurons important to vocal perception and production. How vocalizations are represented by spatiotemporal activity patterns in these neuronal populations remains poorly understood. Here we combined intracellular recordings and two-photon calcium imaging in anesthetized adult zebra finches (Taeniopygia guttata) to examine how learned birdsong and its component syllables are represented in identified projection neurons (PNs) within HVC, a sensorimotor region important for song perception and production. These experiments show that neighboring HVC PNs can respond at markedly different times to song playback and that different syllables activate spatially intermingled PNs within a local (~100 μm) region of HVC. Moreover, noise correlations were stronger between PNs that responded most strongly to the same syllable and were spatially graded within and between classes of PNs. These findings support a model in which syllabic and temporal features of song are represented by spatially intermingled PNs functionally organized into cell- and syllable-type networks within local spatial scales in HVC. Copyright © 2015 the authors 0270-6474/15/355589-17$15.00/0.

The Role of Syllables in Intermediate-Depth Stress-Timed Languages: Masked Priming Evidence in European Portuguese

Science.gov (United States)

Campos, Ana Duarte; Mendes Oliveira, Helena; Soares, Ana Paula

2018-01-01

The role of syllables as a sublexical unit in visual word recognition and reading is well established in deep and shallow syllable-timed languages such as French and Spanish, respectively. However, its role in intermediate stress-timed languages remains unclear. This paper aims to overcome this gap by studying for the first time the role of…

Electrophysiological and hemodynamic mismatch responses in rats listening to human speech syllables.

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Mahdi Mahmoudzadeh

Full Text Available Speech is a complex auditory stimulus which is processed according to several time-scales. Whereas consonant discrimination is required to resolve rapid acoustic events, voice perception relies on slower cues. Humans, right from preterm ages, are particularly efficient to encode temporal cues. To compare the capacities of preterms to those observed in other mammals, we tested anesthetized adult rats by using exactly the same paradigm as that used in preterm neonates. We simultaneously recorded neural (using ECoG and hemodynamic responses (using fNIRS to series of human speech syllables and investigated the brain response to a change of consonant (ba vs. ga and to a change of voice (male vs. female. Both methods revealed concordant results, although ECoG measures were more sensitive than fNIRS. Responses to syllables were bilateral, but with marked right-hemispheric lateralization. Responses to voice changes were observed with both methods, while only ECoG was sensitive to consonant changes. These results suggest that rats more effectively processed the speech envelope than fine temporal cues in contrast with human preterm neonates, in whom the opposite effects were observed. Cross-species comparisons constitute a very valuable tool to define the singularities of the human brain and species-specific bias that may help human infants to learn their native language.

The predominance of strong initial syllables in the English vocabulary

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Cutler, A.; Carter, D.M.

1987-01-01

Studies of human speech processing have provided evidece for a segmentation strategy in the perception of continuous speech, whereby a word boundary is postulated, and a lexical access procedure initiated, at each metrically strong syllable. The likely success of this strategy was here estimated

The binary branching nature of syllable constituents: the English onset

African Journals Online (AJOL)

Motivating evidence is drawn from other languages, specifically Italian, Spanish and Portuguese, because it is believed that, except for the coda, the binary branching nature of syllable constituents is universally imposed in the world\\'s languages. Also, no one language or dialect can exhaustively account for all linguistic ...

Syllabic Length Effect in Visual Word Recognition

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Roya Ranjbar Mohammadi

2014-07-01

Full Text Available Studies on visual word recognition have resulted in different and sometimes contradictory proposals as Multi-Trace Memory Model (MTM, Dual-Route Cascaded Model (DRC, and Parallel Distribution Processing Model (PDP. The role of the number of syllables in word recognition was examined by the use of five groups of English words and non-words. The reaction time of the participants to these words was measured using reaction time measuring software. The results indicated that there was syllabic effect on recognition of both high and low frequency words. The pattern was incremental in terms of syllable number. This pattern prevailed in high and low frequency words and non-words except in one syllable words. In general, the results are in line with the PDP model which claims that a single processing mechanism is used in both words and non-words recognition. In other words, the findings suggest that lexical items are mainly processed via a lexical route.  A pedagogical implication of the findings would be that reading in English as a foreign language involves analytical processing of the syllable of the words.

Beyond single syllables: large-scale modeling of reading aloud with the Connectionist Dual Process (CDP++) model.

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Perry, Conrad; Ziegler, Johannes C; Zorzi, Marco

2010-09-01

Most words in English have more than one syllable, yet the most influential computational models of reading aloud are restricted to processing monosyllabic words. Here, we present CDP++, a new version of the Connectionist Dual Process model (Perry, Ziegler, & Zorzi, 2007). CDP++ is able to simulate the reading aloud of mono- and disyllabic words and nonwords, and learns to assign stress in exactly the same way as it learns to associate graphemes with phonemes. CDP++ is able to simulate the monosyllabic benchmark effects its predecessor could, and therefore shows full backwards compatibility. CDP++ also accounts for a number of novel effects specific to disyllabic words, including the effects of stress regularity and syllable number. In terms of database performance, CDP++ accounts for over 49% of the reaction time variance on items selected from the English Lexicon Project, a very large database of several thousand of words. With its lexicon of over 32,000 words, CDP++ is therefore a notable example of the successful scaling-up of a connectionist model to a size that more realistically approximates the human lexical system. Copyright © 2010 Elsevier Inc. All rights reserved.

Phrase-Final Syllable Lengthening and Intonation in Early Child Speech.

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Snow, David

1994-01-01

To test opposing theories about the relationship between intonation and syllable timing, these boundary features were compared in a longitudinal study of 9 children's speech development between the mean ages of 16 and 25 months. Results suggest that young children acquire the skills that control intonation earlier than they do skills of final…

Short-Term and Long-Term Effects on Visual Word Recognition

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Protopapas, Athanassios; Kapnoula, Efthymia C.

2016-01-01

Effects of lexical and sublexical variables on visual word recognition are often treated as homogeneous across participants and stable over time. In this study, we examine the modulation of frequency, length, syllable and bigram frequency, orthographic neighborhood, and graphophonemic consistency effects by (a) individual differences, and (b) item…

Audio-visual onset differences are used to determine syllable identity for ambiguous audio-visual stimulus pairs.

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Ten Oever, Sanne; Sack, Alexander T; Wheat, Katherine L; Bien, Nina; van Atteveldt, Nienke

2013-01-01

Content and temporal cues have been shown to interact during audio-visual (AV) speech identification. Typically, the most reliable unimodal cue is used more strongly to identify specific speech features; however, visual cues are only used if the AV stimuli are presented within a certain temporal window of integration (TWI). This suggests that temporal cues denote whether unimodal stimuli belong together, that is, whether they should be integrated. It is not known whether temporal cues also provide information about the identity of a syllable. Since spoken syllables have naturally varying AV onset asynchronies, we hypothesize that for suboptimal AV cues presented within the TWI, information about the natural AV onset differences can aid in speech identification. To test this, we presented low-intensity auditory syllables concurrently with visual speech signals, and varied the stimulus onset asynchronies (SOA) of the AV pair, while participants were instructed to identify the auditory syllables. We revealed that specific speech features (e.g., voicing) were identified by relying primarily on one modality (e.g., auditory). Additionally, we showed a wide window in which visual information influenced auditory perception, that seemed even wider for congruent stimulus pairs. Finally, we found a specific response pattern across the SOA range for syllables that were not reliably identified by the unimodal cues, which we explained as the result of the use of natural onset differences between AV speech signals. This indicates that temporal cues not only provide information about the temporal integration of AV stimuli, but additionally convey information about the identity of AV pairs. These results provide a detailed behavioral basis for further neuro-imaging and stimulation studies to unravel the neurofunctional mechanisms of the audio-visual-temporal interplay within speech perception.

Attention Is Required for Knowledge-Based Sequential Grouping: Insights from the Integration of Syllables into Words.

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Ding, Nai; Pan, Xunyi; Luo, Cheng; Su, Naifei; Zhang, Wen; Zhang, Jianfeng

2018-01-31

How the brain groups sequential sensory events into chunks is a fundamental question in cognitive neuroscience. This study investigates whether top-down attention or specific tasks are required for the brain to apply lexical knowledge to group syllables into words. Neural responses tracking the syllabic and word rhythms of a rhythmic speech sequence were concurrently monitored using electroencephalography (EEG). The participants performed different tasks, attending to either the rhythmic speech sequence or a distractor, which was another speech stream or a nonlinguistic auditory/visual stimulus. Attention to speech, but not a lexical-meaning-related task, was required for reliable neural tracking of words, even when the distractor was a nonlinguistic stimulus presented cross-modally. Neural tracking of syllables, however, was reliably observed in all tested conditions. These results strongly suggest that neural encoding of individual auditory events (i.e., syllables) is automatic, while knowledge-based construction of temporal chunks (i.e., words) crucially relies on top-down attention. SIGNIFICANCE STATEMENT Why we cannot understand speech when not paying attention is an old question in psychology and cognitive neuroscience. Speech processing is a complex process that involves multiple stages, e.g., hearing and analyzing the speech sound, recognizing words, and combining words into phrases and sentences. The current study investigates which speech-processing stage is blocked when we do not listen carefully. We show that the brain can reliably encode syllables, basic units of speech sounds, even when we do not pay attention. Nevertheless, when distracted, the brain cannot group syllables into multisyllabic words, which are basic units for speech meaning. Therefore, the process of converting speech sound into meaning crucially relies on attention. Copyright © 2018 the authors 0270-6474/18/381178-11$15.00/0.

The effects of background noise on dichotic listening to consonant-vowel syllables: An fMRI study.

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Dos Santos Sequeira, Sarah; Specht, Karsten; Moosmann, Matthias; Westerhausen, Rene; Hugdahl, Kenneth

2010-11-01

The present fMRI study attempts to identify brain areas that may underlie the effect of different background noises on functional brain asymmetry in a dichotic listening task. Previous studies have shown that the prominent right ear advantage in dichotic listening to consonant-vowel syllables is affected by background noise. To explore the underlying neuronal processes, haemodynamic brain responses using fMRI were recorded while participants performed the dichotic listening task in two different noisy backgrounds (conversational "babble" and traffic noise). The behavioural results showed a reduction of the right ear advantage in the background noise conditions, especially in the traffic noise condition. The behavioural results are discussed in terms of alertness-attentional mechanisms. The effects of background noise on brain activation involved significant activations in a speech-processing network. Specifically the changes in activations in the peri-Sylvian region of the superior temporal gyrus and in the temporo-parietal junction part in the left hemisphere, as well as in the superior temporal gyrus/sulcus area in the right hemisphere may mirror the effects of noise on behavioural performance. The effects of noise on brain activation are discussed with regard to pre-activation mechanisms.

Impaired Perception of Syllable Stress in Children with Dyslexia: A Longitudinal Study

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Goswami, Usha; Mead, Natasha; Fosker, Tim; Huss, Martina; Barnes, Lisa; Leong, Victoria

2013-01-01

Prosodic patterning is a key structural element of spoken language. However, the potential role of prosodic awareness in the phonological difficulties that characterise children with developmental dyslexia has been little studied. Here we report the first longitudinal study of sensitivity to syllable stress in children with dyslexia, enabling the…

Stuttering Frequency, Speech Rate, Speech Naturalness, and Speech Effort During the Production of Voluntary Stuttering.

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Davidow, Jason H; Grossman, Heather L; Edge, Robin L

2018-05-01

Voluntary stuttering techniques involve persons who stutter purposefully interjecting disfluencies into their speech. Little research has been conducted on the impact of these techniques on the speech pattern of persons who stutter. The present study examined whether changes in the frequency of voluntary stuttering accompanied changes in stuttering frequency, articulation rate, speech naturalness, and speech effort. In total, 12 persons who stutter aged 16-34 years participated. Participants read four 300-syllable passages during a control condition, and three voluntary stuttering conditions that involved attempting to produce purposeful, tension-free repetitions of initial sounds or syllables of a word for two or more repetitions (i.e., bouncing). The three voluntary stuttering conditions included bouncing on 5%, 10%, and 15% of syllables read. Friedman tests and follow-up Wilcoxon signed ranks tests were conducted for the statistical analyses. Stuttering frequency, articulation rate, and speech naturalness were significantly different between the voluntary stuttering conditions. Speech effort did not differ between the voluntary stuttering conditions. Stuttering frequency was significantly lower during the three voluntary stuttering conditions compared to the control condition, and speech effort was significantly lower during two of the three voluntary stuttering conditions compared to the control condition. Due to changes in articulation rate across the voluntary stuttering conditions, it is difficult to conclude, as has been suggested previously, that voluntary stuttering is the reason for stuttering reductions found when using voluntary stuttering techniques. Additionally, future investigations should examine different types of voluntary stuttering over an extended period of time to determine their impact on stuttering frequency, speech rate, speech naturalness, and speech effort.

The Role of Secondary-Stressed and Unstressed-Unreduced Syllables in Word Recognition: Acoustic and Perceptual Studies with Russian Learners of English

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Banzina, Elina; Dilley, Laura C.; Hewitt, Lynne E.

2016-01-01

The importance of secondary-stressed (SS) and unstressed-unreduced (UU) syllable accuracy for spoken word recognition in English is as yet unclear. An acoustic study first investigated Russian learners' of English production of SS and UU syllables. Significant vowel quality and duration reductions in Russian-spoken SS and UU vowels were found,…

Volubility, consonant, and syllable characteristics in infants and toddlers later diagnosed with childhood apraxia of speech: A pilot study.

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Overby, Megan; Caspari, Susan S

2015-01-01

This pilot study explored the volubility, consonant singleton acquisition, and syllable structure development between infants and toddlers (birth-24 months) with typical speech sound production (TYP) and those later diagnosed with childhood apraxia of speech (CAS). A retrospective longitudinal between- and within-subjects research design was utilized (TYP N=2; CAS N=4). Vocalizations from participants were analyzed between birth-24 months from home videotapes, volunteered by the children's parents, according to type (nonresonant vs. resonant), volubility, place and manner of consonant singletons, and syllable shape (V, CV, VC, CVC, VCV, CVCV, VCVC, and "Other"). Volubility between groups was not significant but statistically significant differences were found in the number of: resonant and non-resonant productions; different consonant singletons; different place features; different manner classes; and proportional use of fricative, glottal, and voiceless phones. Infants and toddlers in the CAS group also demonstrated difficulty with CVCs, had limited syllable shapes, and possible regression of vowel syllable structure. Data corroborate parent reports that infants and toddlers later diagnosed with CAS present differently than do those with typical speech sound skills. Additional study with infants and toddlers later diagnosed with non-CAS speech sound disorder is needed. Readers will: (1) describe current perspectives on volubility of infants and toddlers later diagnosed with CAS; (2) describe current perspectives of the consonant singleton and syllable shape inventories of infants and toddlers later diagnosed with CAS; and (3) discuss the potential differences between the speech sound development of infants and toddlers later diagnosed with CAS and those with typical speech sound skill. Copyright © 2015 Elsevier Inc. All rights reserved.

Measures of speech rhythm and the role of corpus-based word frequency: a multifactorial comparison of Spanish(-English speakers

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Michael J. Harris

2011-12-01

Full Text Available In this study, we address various measures that have been employed to distinguish between syllable and stress- timed languages. This study differs from all previous ones by (i exploring and comparing multiple metrics within a quantitative and multifactorial perspective and by (ii also documenting the impact of corpus-based word frequency. We begin with the basic distinctions of speech rhythms, dealing with the differences between syllable-timed languages and stress-timed languages and several methods that have been used to attempt to distinguish between the two. We then describe how these metrics were used in the current study comparing the speech rhythms of Mexican Spanish speakers and bilingual English/Spanish speakers (speakers born to Mexican parents in California. More specifically, we evaluate how well various metrics of vowel duration variability as well as the so far understudied factor of corpus-based frequency allow to classify speakers as monolingual or bilingual. A binary logistic regression identifies several main effects and interactions. Most importantly, our results call the utility of a particular rhythm metric, the PVI, into question and indicate that corpus data in the form of lemma frequencies interact with two metrics of durational variability, suggesting that durational variability metrics should ideally be studied in conjunction with corpus-based frequency data.

Altered auditory BOLD response to conspecific birdsong in zebra finches with stuttered syllables.

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Henning U Voss

2010-12-01

Full Text Available How well a songbird learns a song appears to depend on the formation of a robust auditory template of its tutor's song. Using functional magnetic resonance neuroimaging we examine auditory responses in two groups of zebra finches that differ in the type of song they sing after being tutored by birds producing stuttering-like syllable repetitions in their songs. We find that birds that learn to produce the stuttered syntax show attenuated blood oxygenation level-dependent (BOLD responses to tutor's song, and more pronounced responses to conspecific song primarily in the auditory area field L of the avian forebrain, when compared to birds that produce normal song. These findings are consistent with the presence of a sensory song template critical for song learning in auditory areas of the zebra finch forebrain. In addition, they suggest a relationship between an altered response related to familiarity and/or saliency of song stimuli and the production of variant songs with stuttered syllables.

A Nonword Repetition Task for Speakers with Misarticulations: The Syllable Repetition Task (SRT)

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Shriberg, Lawrence D.; Lohmeier, Heather L.; Campbell, Thomas F.; Dollaghan, Christine A.; Green, Jordan R.; Moore, Christopher A.

2009-01-01

Purpose: Conceptual and methodological confounds occur when non(sense) word repetition tasks are administered to speakers who do not have the target speech sounds in their phonetic inventories or who habitually misarticulate targeted speech sounds. In this article, the authors (a) describe a nonword repetition task, the Syllable Repetition Task…

Processing of syllable stress is functionally different from phoneme processing and does not profit from literacy acquisition

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Ulrike eSchild

2014-06-01

Full Text Available Speech is characterized by phonemes and prosody. Neurocognitive evidence supports the separate processing of each type of information. Therefore, one might suggest individual development of both pathways. In this study, we examine literacy acquisition in middle childhood. Children become aware of the phonemes in speech at that time and refine phoneme processing when they acquire an alphabetic writing system. We test whether an enhanced sensitivity to phonemes in middle childhood extends to other aspects of the speech signal, such as prosody. To investigate prosodic processing, we used stress priming. Spoken stressed and unstressed syllables (primes preceded spoken German words with stress on the first syllable (targets. We orthogonally varied stress overlap and phoneme overlap between the primes and onsets of the targets. Lexical decisions and Event-Related Potentials (ERPs for the targets were obtained for pre-reading preschoolers, reading pupils and adults. The behavioral and ERP results were largely comparable across all groups. The fastest responses were observed when the first syllable of the target word shared stress and phonemes with the preceding prime. ERP stress priming and ERP phoneme priming started 200 ms after the target word onset. Bilateral ERP stress priming was characterized by enhanced ERP amplitudes for stress overlap. Left-lateralized ERP phoneme priming replicates previously observed reduced ERP amplitudes for phoneme overlap. Groups differed in the strength of the behavioral phoneme priming and in the late ERP phoneme priming effect. The present results show that enhanced phonological processing in middle childhood is restricted to phonemes and does not extend to prosody. These results are indicative of two parallel processing systems for phonemes and prosody that might follow different developmental trajectories in middle childhood as a function of alphabetic literacy.

Telehealth Delivery of Rapid Syllable Transitions (ReST) Treatment for Childhood Apraxia of Speech

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Thomas, Donna C.; McCabe, Patricia; Ballard, Kirrie J.; Lincoln, Michelle

2016-01-01

Background: Rapid Syllable Transitions (ReST) treatment uses pseudo-word targets with varying lexical stress to target simultaneously articulation, prosodic accuracy and coarticulatory transitions in childhood apraxia of speech (CAS). The treatment is efficacious for the acquisition of imitated pseudo-words, and generalization of skill to…

Duration of Stuttered Syllables Measured by “Computerized Scoring of the Stuttering Severity (CSSS” and “Pratt”

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Hossein Rezai

2017-06-01

Discussion: Higher reliability and replicability of duration values calculated by Praat software indicates that this software can be applied for more precise determination of duration of stuttered syllables. 

Comparison of spectrographic records of two syllables pronounced from scripts in hiragana and romaji by students with different familiarity with English.

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Ototake, Harumi; Yamada, Jun

2005-10-01

The same syllables /mu/ and /ra/ written in Japanese hiragana and romaji given on a standard speeded naming task elicited phonetically or acoustically different responses in a syllabic hiragana condition and a romaji condition. The participants were two groups of Japanese college students (ns = 15 and 16) with different familiarity with English as a second language. The results suggested that the phonetic reality of syllables represented in these scripts can differ, depending on the interaction between the kind of script and speakers' orthographic familiarity.

Invented Spelling, Word Stress, and Syllable Awareness in Relation to Reading Difficulties in Children.

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Mehta, Sheena; Ding, Yi; Ness, Molly; Chen, Eric C

2018-06-01

The study assessed the clinical utility of an invented spelling tool and determined whether invented spelling with linguistic manipulation at segmental and supra-segmental levels can be used to better identify reading difficulties. We conducted linguistic manipulation by using real and nonreal words, incorporating word stress, alternating the order of consonants and vowels, and alternating the number of syllables. We recruited 60 third-grade students, of which half were typical readers and half were poor readers. The invented spelling task consistently differentiated those with reading difficulties from typical readers. It explained unique variance in conventional spelling, but not in word reading. Word stress explained unique variance in both word reading and conventional spelling, highlighting the importance of addressing phonological awareness at the supra-segmental level. Poor readers had poorer performance when spelling both real and nonreal words and demonstrated substantial difficulty in detecting word stress. Poor readers struggled with spelling words with double consonants at the beginning and ending of words, and performed worse on spelling two- and three-syllable words than typical readers. Practical implications for early identification and instruction are discussed.

Using Statistical Process Control Charts to Study Stuttering Frequency Variability during a Single Day

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Karimi, Hamid; O'Brian, Sue; Onslow, Mark; Jones, Mark; Menzies, Ross; Packman, Ann

2013-01-01

Purpose: Stuttering varies between and within speaking situations. In this study, the authors used statistical process control charts with 10 case studies to investigate variability of stuttering frequency. Method: Participants were 10 adults who stutter. The authors counted the percentage of syllables stuttered (%SS) for segments of their speech…

THE SYLLABLE STRUCTURE IN EUROPEAN PORTUGUESE A Estrutura da Sílaba em Português Europeu

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Maria Helena Mateus

1998-02-01

Full Text Available The goal of this paper is to discuss the internal structure of the syllable in European Portuguese and to propose an algorithm for base syllabification. Due to the analysis of consonant clusters in onset position and the occurrence of epenthetic vowels, and considering the variation of the vowels in word initial position that occupy the syllable nucleus without an onset at the phonetic level, we assume that, in European Portuguese, the syllable is always constituted by an onset and a rhyme even though one of these constituents (but not both may be empty, that is, one of then may have no phonetic realisation.O objetivo deste artigo é o de discutir a estrutura interna da sílaba em Português Europeu e o de propor um algoritmo para a silabificação de base. Tendo en conta a análise dos grupos de consoantes que ocupam o lugar de ataque e a possibilidade de existência de vogais epentéticas que desfazem alguns desses grupos, e considerando, ainda, a variação de vogais em posição inicial de palavra que constituem núcleo de sílaba sem ataque no nível fonético, apresenta-se a hipótese de que a sílaba, em Português Europeu, é sempre constituída por um ataque e por uma rima, mesmo que um desses constituintes (mas não os dois seja vazio. Ou seja, um dos dois constituintes pode não ter realização fonética.

Amplitude and frequency modulation control of sound production in a mechanical model of the avian syrinx

DEFF Research Database (Denmark)

Elemans, Coen; Muller, Mees; Larsen, Ole Næsbye

2009-01-01

membrane and generate a wide variety of ‘syllables' with simple sweeps of the control parameters. We show that the membrane exhibits high frequency, self-sustained oscillations in the audio range (>600 Hz fundamental frequency) using laser Doppler vibrometry, and systematically explore the conditions...... for sound production of the model in its control space. The fundamental frequency of the sound increases with tension in three membranes with different stiffness and mass. The lowerbound fundamental frequency increases with membrane mass. The membrane vibrations are strongly coupled to the resonance...

General contrast effects in speech perception: effect of preceding liquid on stop consonant identification.

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Lotto, A J; Kluender, K R

1998-05-01

When members of a series of synthesized stop consonants varying acoustically in F3 characteristics and varying perceptually from /da/ to /ga/ are preceded by /al/, subjects report hearing more /ga/ syllables relative to when each member is preceded by /ar/ (Mann, 1980). It has been suggested that this result demonstrates the existence of a mechanism that compensates for coarticulation via tacit knowledge of articulatory dynamics and constraints, or through perceptual recovery of vocal-tract dynamics. The present study was designed to assess the degree to which these perceptual effects are specific to qualities of human articulatory sources. In three experiments, series of consonant-vowel (CV) stimuli varying in F3-onset frequency (/da/-/ga/) were preceded by speech versions or nonspeech analogues of /al/ and /ar/. The effect of liquid identity on stop consonant labeling remained when the preceding VC was produced by a female speaker and the CV syllable was modeled after a male speaker's productions. Labeling boundaries also shifted when the CV was preceded by a sine wave glide modeled after F3 characteristics of /al/ and /ar/. Identifications shifted even when the preceding sine wave was of constant frequency equal to the offset frequency of F3 from a natural production. These results suggest an explanation in terms of general auditory processes as opposed to recovery of or knowledge of specific articulatory dynamics.

A comparison of aphasic and non-brain-injured adults on a dichotic CV-syllable listening task.

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Shanks, J; Ryan, W

1976-06-01

A dichotic CV-syllable listening task was administered to a group of eleven non-brain-injured adults and to a group of eleven adult aphasics. The results of this study may be summarized as follows: 1)The group of non-brain-injured adults showed a slight right ear advantage for dichotically presented CV-syllables. 2)In comparison with the control group the asphasic group showed a bilateral deficit in response to the dichotic CV-syllables, superimposed on a non-significant right ear advantage. 3) The asphasic group demonstrated a great deal of intersubject variability on the dichotic task with six aphasics showing a right ear preference for the stimuli. The non-brain-injured subjects performed more homogeneously on the task. 4) The two subgroups of aphasics, a right ear advantage group and a left ear advantage group, performed significantly different on the dichotic listening task. 5) Single correct data analysis proved valuable by deleting accuracy of report for an examination of trials in which there was true competition for the single left hemispheric speech processor. These results were analyzed in terms of a functional model of auditory processing. In view of this model, the bilateral deficit in dichotic performance of the asphasic group was accounted for by the presence of a lesion within the dominant left hemisphere, where the speech signals from both ears converge for final processing. The right ear advantage shown by one asphasic subgroup was explained by a lesion interfering with the corpus callosal pathways from the left hemisphere; the left ear advantage observed within the other subgroup was explained by a lesion in the area of the auditory processor of the left hemisphere.

Analysis of error type and frequency in apraxia of speech among Portuguese speakers

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Maysa Luchesi Cera

Full Text Available Abstract Most studies characterizing errors in the speech of patients with apraxia involve English language. Objectives: To analyze the types and frequency of errors produced by patients with apraxia of speech whose mother tongue was Brazilian Portuguese. Methods: 20 adults with apraxia of speech caused by stroke were assessed. The types of error committed by patients were analyzed both quantitatively and qualitatively, and frequencies compared. Results: We observed the presence of substitution, omission, trial-and-error, repetition, self-correction, anticipation, addition, reiteration and metathesis, in descending order of frequency, respectively. Omission type errors were one of the most commonly occurring whereas addition errors were infrequent. These findings differed to those reported in English speaking patients, probably owing to differences in the methodologies used for classifying error types; the inclusion of speakers with apraxia secondary to aphasia; and the difference in the structure of Portuguese language to English in terms of syllable onset complexity and effect on motor control. Conclusions: The frequency of omission and addition errors observed differed to the frequency reported for speakers of English.

Analysis of error type and frequency in apraxia of speech among Portuguese speakers.

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Cera, Maysa Luchesi; Minett, Thaís Soares Cianciarullo; Ortiz, Karin Zazo

2010-01-01

Most studies characterizing errors in the speech of patients with apraxia involve English language. To analyze the types and frequency of errors produced by patients with apraxia of speech whose mother tongue was Brazilian Portuguese. 20 adults with apraxia of speech caused by stroke were assessed. The types of error committed by patients were analyzed both quantitatively and qualitatively, and frequencies compared. We observed the presence of substitution, omission, trial-and-error, repetition, self-correction, anticipation, addition, reiteration and metathesis, in descending order of frequency, respectively. Omission type errors were one of the most commonly occurring whereas addition errors were infrequent. These findings differed to those reported in English speaking patients, probably owing to differences in the methodologies used for classifying error types; the inclusion of speakers with apraxia secondary to aphasia; and the difference in the structure of Portuguese language to English in terms of syllable onset complexity and effect on motor control. The frequency of omission and addition errors observed differed to the frequency reported for speakers of English.

Syllable division: Prerequisite to dyslexics' literacy.

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Cox, A R; Hutcheson, L

1988-01-01

Skill in reading long words is prerequisite to dyslexics' literacy. Instant recognition of printed symbols is easy for those readers with photographic memories, but dyslexics often fail to recognize visually many long words which are actually familiar to them auditorially. Scientific, automatic, multisensory procedures for dividing longer words into easily read syllables can enable students to translate visual symbols rapidly and thereby to read, write, or spell accurately words of any length.Over one thousand dyslexics, aged seven to fifteen, guided the interdisciplinary team at Texas Scottish Rite Hospital in Dallas to develop, observe results, and test specific structured, sequential steps in working out longer words. The ten-year study (1965-1975) in the Language Laboratory of the Hospital established the Alphabetic Phonics curriculum which is now used successfully, not only in remedial groups but in regular classes of any size or age, in public and private schools in 45 states and six foreign countries.The newly-established Aylett Royall Cox Institute in Dallas prepares teachers and Master Instructors to train both students and other teachers. Comparable Alphabetic Phonics Teacher Training Centers are already established in Houston and Lubbock, Texas, in Oklahoma City, and at Columbia University Teachers College in New York.

Comparison of Percentage of Syllables Stuttered With Parent-Reported Severity Ratings as a Primary Outcome Measure in Clinical Trials of Early Stuttering Treatment.

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Onslow, Mark; Jones, Mark; O'Brian, Sue; Packman, Ann; Menzies, Ross; Lowe, Robyn; Arnott, Simone; Bridgman, Kate; de Sonneville, Caroline; Franken, Marie-Christine

2018-04-17

This report investigates whether parent-reported stuttering severity ratings (SRs) provide similar estimates of effect size as percentage of syllables stuttered (%SS) for randomized trials of early stuttering treatment with preschool children. Data sets from 3 randomized controlled trials of an early stuttering intervention were selected for analyses. Analyses included median changes and 95% confidence intervals per treatment group, Bland-Altman plots, analysis of covariance, and Spearman rho correlations. Both SRs and %SS showed large effect sizes from pretreatment to follow-up, although correlations between the 2 measures were moderate at best. Absolute agreement between the 2 measures improved as percentage reduction of stuttering frequency and severity increased, probably due to innate measurement limitations for participants with low baseline severity. Analysis of covariance for the 3 trials showed consistent results. There is no statistical reason to favor %SS over parent-reported stuttering SRs as primary outcomes for clinical trials of early stuttering treatment. However, there are logistical reasons to favor parent-reported stuttering SRs. We conclude that parent-reported rating of the child's typical stuttering severity for the week or month prior to each assessment is a justifiable alternative to %SS as a primary outcome measure in clinical trials of early stuttering treatment.

Progressive apraxia of speech as a window into the study of speech planning processes.

Science.gov (United States)

Laganaro, Marina; Croisier, Michèle; Bagou, Odile; Assal, Frédéric

2012-09-01

We present a 3-year follow-up study of a patient with progressive apraxia of speech (PAoS), aimed at investigating whether the theoretical organization of phonetic encoding is reflected in the progressive disruption of speech. As decreased speech rate was the most striking pattern of disruption during the first 2 years, durational analyses were carried out longitudinally on syllables excised from spontaneous, repetition and reading speech samples. The crucial result of the present study is the demonstration of an effect of syllable frequency on duration: the progressive disruption of articulation rate did not affect all syllables in the same way, but followed a gradient that was function of the frequency of use of syllable-sized motor programs. The combination of data from this case of PAoS with previous psycholinguistic and neurolinguistic data, points to a frequency organization of syllable-sized speech-motor plans. In this study we also illustrate how studying PAoS can be exploited in theoretical and clinical investigations of phonetic encoding as it represents a unique opportunity to investigate speech while it progressively disrupts. Copyright © 2011 Elsevier Srl. All rights reserved.

The role of continuous low-frequency harmonicity cues for interrupted speech perception in bimodal hearing.

Science.gov (United States)

Oh, Soo Hee; Donaldson, Gail S; Kong, Ying-Yee

2016-04-01

Low-frequency acoustic cues have been shown to enhance speech perception by cochlear-implant users, particularly when target speech occurs in a competing background. The present study examined the extent to which a continuous representation of low-frequency harmonicity cues contributes to bimodal benefit in simulated bimodal listeners. Experiment 1 examined the benefit of restoring a continuous temporal envelope to the low-frequency ear while the vocoder ear received a temporally interrupted stimulus. Experiment 2 examined the effect of providing continuous harmonicity cues in the low-frequency ear as compared to restoring a continuous temporal envelope in the vocoder ear. Findings indicate that bimodal benefit for temporally interrupted speech increases when continuity is restored to either or both ears. The primary benefit appears to stem from the continuous temporal envelope in the low-frequency region providing additional phonetic cues related to manner and F1 frequency; a secondary contribution is provided by low-frequency harmonicity cues when a continuous representation of the temporal envelope is present in the low-frequency, or both ears. The continuous temporal envelope and harmonicity cues of low-frequency speech are thought to support bimodal benefit by facilitating identification of word and syllable boundaries, and by restoring partial phonetic cues that occur during gaps in the temporally interrupted stimulus.

Assessing vocal performance in complex birdsong: a novel approach.

Science.gov (United States)

Geberzahn, Nicole; Aubin, Thierry

2014-08-06

Vocal performance refers to the ability to produce vocal signals close to physical limits. Such motor skills can be used by conspecifics to assess a signaller's competitive potential. For example it is difficult for birds to produce repeated syllables both rapidly and with a broad frequency bandwidth. Deviation from an upper-bound regression of frequency bandwidth on trill rate has been widely used to assess vocal performance. This approach is, however, only applicable to simple trilled songs, and even then may be affected by differences in syllable complexity. Using skylarks (Alauda arvensis) as a birdsong model with a very complex song structure, we detected another performance trade-off: minimum gap duration between syllables was longer when the frequency ratio between the end of one syllable and the start of the next syllable (inter-syllable frequency shift) was large. This allowed us to apply a novel measure of vocal performance ¿ vocal gap deviation: the deviation from a lower-bound regression of gap duration on inter-syllable frequency shift. We show that skylarks increase vocal performance in an aggressive context suggesting that this trait might serve as a signal for competitive potential. We suggest using vocal gap deviation in future studies to assess vocal performance in songbird species with complex structure.

Metrical expectations from preceding prosody influence perception of lexical stress.

Science.gov (United States)

Brown, Meredith; Salverda, Anne Pier; Dilley, Laura C; Tanenhaus, Michael K

2015-04-01

Two visual-world experiments tested the hypothesis that expectations based on preceding prosody influence the perception of suprasegmental cues to lexical stress. The results demonstrate that listeners' consideration of competing alternatives with different stress patterns (e.g., 'jury/gi'raffe) can be influenced by the fundamental frequency and syllable timing patterns across material preceding a target word. When preceding stressed syllables distal to the target word shared pitch and timing characteristics with the first syllable of the target word, pictures of alternatives with primary lexical stress on the first syllable (e.g., jury) initially attracted more looks than alternatives with unstressed initial syllables (e.g., giraffe). This effect was modulated when preceding unstressed syllables had pitch and timing characteristics similar to the initial syllable of the target word, with more looks to alternatives with unstressed initial syllables (e.g., giraffe) than to those with stressed initial syllables (e.g., jury). These findings suggest that expectations about the acoustic realization of upcoming speech include information about metrical organization and lexical stress and that these expectations constrain the initial interpretation of suprasegmental stress cues. These distal prosody effects implicate online probabilistic inferences about the sources of acoustic-phonetic variation during spoken-word recognition. (c) 2015 APA, all rights reserved.

Effect of high-frequency excitation on natural frequencies of spinning discs

DEFF Research Database (Denmark)

Hansen, Morten Hartvig

2000-01-01

The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural frequenc......The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural...

Effects of age and hearing loss on recognition of unaccented and accented multisyllabic words

Science.gov (United States)

Gordon-Salant, Sandra; Yeni-Komshian, Grace H.; Fitzgibbons, Peter J.; Cohen, Julie I.

2015-01-01

The effects of age and hearing loss on recognition of unaccented and accented words of varying syllable length were investigated. It was hypothesized that with increments in length of syllables, there would be atypical alterations in syllable stress in accented compared to native English, and that these altered stress patterns would be sensitive to auditory temporal processing deficits with aging. Sets of one-, two-, three-, and four-syllable words with the same initial syllable were recorded by one native English and two Spanish-accented talkers. Lists of these words were presented in isolation and in sentence contexts to younger and older normal-hearing listeners and to older hearing-impaired listeners. Hearing loss effects were apparent for unaccented and accented monosyllabic words, whereas age effects were observed for recognition of accented multisyllabic words, consistent with the notion that altered syllable stress patterns with accent are sensitive for revealing effects of age. Older listeners also exhibited lower recognition scores for moderately accented words in sentence contexts than in isolation, suggesting that the added demands on working memory for words in sentence contexts impact recognition of accented speech. The general pattern of results suggests that hearing loss, age, and cognitive factors limit the ability to recognize Spanish-accented speech. PMID:25698021

The effect of deep brain stimulation on the speech motor system.

Science.gov (United States)

Mücke, Doris; Becker, Johannes; Barbe, Michael T; Meister, Ingo; Liebhart, Lena; Roettger, Timo B; Dembek, Till; Timmermann, Lars; Grice, Martine

2014-08-01

Chronic deep brain stimulation of the nucleus ventralis intermedius is an effective treatment for individuals with medication-resistant essential tremor. However, these individuals report that stimulation has a deleterious effect on their speech. The present study investigates one important factor leading to these effects: the coordination of oral and glottal articulation. Sixteen native-speaking German adults with essential tremor, between 26 and 86 years old, with and without chronic deep brain stimulation of the nucleus ventralis intermedius and 12 healthy, age-matched subjects were recorded performing a fast syllable repetition task (/papapa/, /tatata/, /kakaka/). Syllable duration and voicing-to-syllable ratio as well as parameters related directly to consonant production, voicing during constriction, and frication during constriction were measured. Voicing during constriction was greater in subjects with essential tremor than in controls, indicating a perseveration of voicing into the voiceless consonant. Stimulation led to fewer voiceless intervals (voicing-to-syllable ratio), indicating a reduced degree of glottal abduction during the entire syllable cycle. Stimulation also induced incomplete oral closures (frication during constriction), indicating imprecise oral articulation. The detrimental effect of stimulation on the speech motor system can be quantified using acoustic measures at the subsyllabic level.

Contrast effects on stop consonant identification.

Science.gov (United States)

Diehl, R L; Elman, J L; McCusker, S B

1978-11-01

Changes in the identification of speech sounds following selective adaptation are usually attributed to a reduction in sensitivity of auditory feature detectors. An alternative explanation of these effects is based on the notion of response contrast. In several experiments, subjects identified the initial segment of synthetic consonant-vowel syllables as either the voiced stop [b] or the voiceless stop [ph]. Each test syllable had a value of voice onset time (VOT) that placed it near the English voiced-voiceless boundary. When the test syllables were preceded by a single clear [b] (VOT = -100 msec), subjects tended to identify them as [ph], whereas when they were preceded by an unambiguous [ph] (VOT = 100 msec), the syllables were predominantly labeled [b]. This contrast effect occurred even when the contextual stimuli were velar and the test stimuli were bilabial, which suggests a featural rather than a phonemic basis for the effect. To discount the possibility that these might be instances of single-trial sensory adaptation, we conducted a similar experiment in which the contextual stimuli followed the test items. Reliable contrast effects were still obtained. In view of these results, it appears likely that response contrast accounts for at least some component of the adaptation effects reported in the literature.

A Randomized Controlled Trial for Children with Childhood Apraxia of Speech Comparing Rapid Syllable Transition Treatment and the Nuffield Dyspraxia Programme-Third Edition

Science.gov (United States)

Murray, Elizabeth; McCabe, Patricia; Ballard, Kirrie J.

2015-01-01

Purpose: This randomized controlled trial compared the experimental Rapid Syllable Transition (ReST) treatment to the Nuffield Dyspraxia Programme-Third Edition (NDP3; Williams & Stephens, 2004), used widely in clinical practice in Australia and the United Kingdom. Both programs aim to improve speech motor planning/programming for children…

Fa-fa-fa-fa, de doo doo doo, de da da da, sha la la la lee : What is the optimal syllable in improvised singing?

NARCIS (Netherlands)

van Eerten, Laura; Gilbers, Dicky; Lowie, Wander; Kager, René; Grijzenhout, Janet; Sebregts, Koen

2014-01-01

The aim of this paper is to describe and account for the optimal syllable structure in improvised singing without lyrics. Improvised singing has an overall relaxed character and it is abstracted from meaning. Furthermore, singing in general involves an exaggerated articulation of speech sounds.

Lexical tone and stuttering loci in Mandarin: evidence from preschool children who stutter.

Science.gov (United States)

Chou, Fang-Chi; Zebrowski, Patricia; Yang, Shu-Lan

2015-02-01

The purpose of this study was to examine the relationship between stuttering loci and lexical tone in Mandarin-speaking preschoolers. Conversational samples from 20 Taiwanese children who stutter (CWS; M = 4:9; range = 3:2-6:4) were analysed for frequency and type of speech disfluency and lexical tone associated with stuttering-like disfluencies (SLDs). Results indicated that SLDs were significantly more likely to be produced on Mandarin syllables carrying Tone 3 and Tone 4 syllables compared to syllables carrying either Tone 1 or Tone 2. Post-hoc analyses revealed: (1) no significant differences in the stuttering frequencies between Tone 1 and Tone 2, or between Tone 3 and Tone 4, and (2) a higher incidence of stuttering on syllables carrying Tone 3 and Tone 4 embedded in conflicting (as opposed to compatible) tonal contexts. Results suggest that the higher incidence of stuttering on Mandarin syllables carrying either Tone 3 or 4 may be attributed to the increased level of speech motor demand underlying rapid F0 change both within and across syllables.

Stereotypy and variability of social calls among clustering female big-footed myotis (Myotis macrodactylus).

Science.gov (United States)

Xiao, Yan-Hong; Wang, Lei; Hoyt, Joseph R; Jiang, Ting-Lei; Lin, Ai-Qing; Feng, Jiang

2018-03-18

Echolocating bats have developed advanced auditory perception systems, predominantly using acoustic signaling to communicate with each other. They can emit a diverse range of social calls in complex behavioral contexts. This study examined the vocal repertoire of five pregnant big-footed myotis bats (Myotis macrodactylus). In the process of clustering, the last individual to return to the colony (LI) emitted social calls that correlated with behavior, as recorded on a PC-based digital recorder. These last individuals could emit 10 simple monosyllabic and 27 complex multisyllabic types of calls, constituting four types of syllables. The social calls were composed of highly stereotyped syllables, hierarchically organized by a common set of syllables. However, intra-specific variation was also found in the number of syllables, syllable order and patterns of syllable repetition across call renditions. Data were obtained to characterize the significant individual differences that existed in the maximum frequency and duration of calls. Time taken to return to the roost was negatively associated with the diversity of social calls. Our findings indicate that variability in social calls may be an effective strategy taken by individuals during reintegration into clusters of female M. macrodactylus.

Female presence and estrous state influence mouse ultrasonic courtship vocalizations.

Directory of Open Access Journals (Sweden)

Jessica L Hanson

Full Text Available The laboratory mouse is an emerging model for context-dependent vocal signaling and reception. Mouse ultrasonic vocalizations are robustly produced in social contexts. In adults, male vocalization during courtship has become a model of interest for signal-receiver interactions. These vocalizations can be grouped into syllable types that are consistently produced by different subspecies and strains of mice. Vocalizations are unique to individuals, vary across development, and depend on social housing conditions. The behavioral significance of different syllable types, including the contexts in which different vocalizations are made and the responses listeners have to different types of vocalizations, is not well understood. We examined the effect of female presence and estrous state on male vocalizations by exploring the use of syllable types and the parameters of syllables during courtship. We also explored correlations between vocalizations and other behaviors. These experimental manipulations produced four main findings: 1 vocalizations varied among males, 2 the production of USVs and an increase in the use of a specific syllable type were temporally related to mounting behavior, 3 the frequency (kHz, bandwidth, and duration of syllables produced by males were influenced by the estrous phase of female partners, and 4 syllable types changed when females were removed. These findings show that mouse ultrasonic courtship vocalizations are sensitive to changes in female phase and presence, further demonstrating the context-sensitivity of these calls.

Effective switching frequency multiplier inverter

Science.gov (United States)

Su, Gui-Jia [Oak Ridge, TN; Peng, Fang Z [Okemos, MI

2007-08-07

A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

E-Hitz: a word frequency list and a program for deriving psycholinguistic statistics in an agglutinative language (Basque).

Science.gov (United States)

Perea, Manuel; Urkia, Miriam; Davis, Colin J; Agirre, Ainhoa; Laseka, Edurne; Carreiras, Manuel

2006-11-01

We describe a Windows program that enables users to obtain a broad range of statistics concerning the properties of word and nonword stimuli in an agglutinative language (Basque), including measures of word frequency (at the whole-word and lemma levels), bigram and biphone frequency, orthographic similarity, orthographic and phonological structure, and syllable-based measures. It is designed for use by researchers in psycholinguistics, particularly those concerned with recognition of isolated words and morphology. In addition to providing standard orthographic and phonological neighborhood measures, the program can be used to obtain information about other forms of orthographic similarity, such as transposed-letter similarity and embedded-word similarity. It is available free of charge from www .uv.es/mperea/E-Hitz.zip.

Effect of attentional load on audiovisual speech perception: Evidence from ERPs

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Agnès eAlsius

2014-07-01

Full Text Available Seeing articulatory movements influences perception of auditory speech. This is often reflected in a shortened latency of auditory event-related potentials (ERPs generated in the auditory cortex. The present study addressed whether this early neural correlate of audiovisual interaction is modulated by attention. We recorded ERPs in 15 subjects while they were presented with auditory, visual and audiovisual spoken syllables. Audiovisual stimuli consisted of incongruent auditory and visual components known to elicit a McGurk effect, i.e. a visually driven alteration in the auditory speech percept. In a Dual task condition, participants were asked to identify spoken syllables whilst monitoring a rapid visual stream of pictures for targets, i.e., they had to divide their attention. In a Single task condition, participants identified the syllables without any other tasks, i.e., they were asked to ignore the pictures and focus their attention fully on the spoken syllables. The McGurk effect was weaker in the Dual task than in the Single task condition, indicating an effect of attentional load on audiovisual speech perception. Early auditory ERP components, N1 and P2, peaked earlier to audiovisual stimuli than to auditory stimuli when attention was fully focused on syllables, indicating neurophysiological audiovisual interaction. This latency decrement was reduced when attention was loaded, suggesting that attention influences early neural processing of audiovisual speech. We conclude that reduced attention weakens the interaction between vision and audition in speech.

Effect of attentional load on audiovisual speech perception: evidence from ERPs.

Science.gov (United States)

Alsius, Agnès; Möttönen, Riikka; Sams, Mikko E; Soto-Faraco, Salvador; Tiippana, Kaisa

2014-01-01

Seeing articulatory movements influences perception of auditory speech. This is often reflected in a shortened latency of auditory event-related potentials (ERPs) generated in the auditory cortex. The present study addressed whether this early neural correlate of audiovisual interaction is modulated by attention. We recorded ERPs in 15 subjects while they were presented with auditory, visual, and audiovisual spoken syllables. Audiovisual stimuli consisted of incongruent auditory and visual components known to elicit a McGurk effect, i.e., a visually driven alteration in the auditory speech percept. In a Dual task condition, participants were asked to identify spoken syllables whilst monitoring a rapid visual stream of pictures for targets, i.e., they had to divide their attention. In a Single task condition, participants identified the syllables without any other tasks, i.e., they were asked to ignore the pictures and focus their attention fully on the spoken syllables. The McGurk effect was weaker in the Dual task than in the Single task condition, indicating an effect of attentional load on audiovisual speech perception. Early auditory ERP components, N1 and P2, peaked earlier to audiovisual stimuli than to auditory stimuli when attention was fully focused on syllables, indicating neurophysiological audiovisual interaction. This latency decrement was reduced when attention was loaded, suggesting that attention influences early neural processing of audiovisual speech. We conclude that reduced attention weakens the interaction between vision and audition in speech.

Beyond Phonotactic Frequency: Presentation Frequency Effects Word Productions in Specific Language Impairment

Science.gov (United States)

Plante, Elena; Bahl, Megha; Vance, Rebecca; Gerken, LouAnn

2011-01-01

Phonotactic frequency effects on word production are thought to reflect accumulated experience with a language. Here we demonstrate that frequency effects can also be obtained through short-term manipulations of the input to children. We presented children with nonwords in an experiment that systematically manipulated English phonotactic frequency…

Prosodic Similarity Effects in Short-Term Memory in Developmental Dyslexia.

Science.gov (United States)

Goswami, Usha; Barnes, Lisa; Mead, Natasha; Power, Alan James; Leong, Victoria

2016-11-01

Children with developmental dyslexia are characterized by phonological difficulties across languages. Classically, this 'phonological deficit' in dyslexia has been investigated with tasks using single-syllable words. Recently, however, several studies have demonstrated difficulties in prosodic awareness in dyslexia. Potential prosodic effects in short-term memory have not yet been investigated. Here we create a new instrument based on three-syllable words that vary in stress patterns, to investigate whether prosodic similarity (the same prosodic pattern of stressed and unstressed syllables) exerts systematic effects on short-term memory. We study participants with dyslexia and age-matched and younger reading-level-matched typically developing controls. We find that all participants, including dyslexic participants, show prosodic similarity effects in short-term memory. All participants exhibited better retention of words that differed in prosodic structure, although participants with dyslexia recalled fewer words accurately overall compared to age-matched controls. Individual differences in prosodic memory were predicted by earlier vocabulary abilities, by earlier sensitivity to syllable stress and by earlier phonological awareness. To our knowledge, this is the first demonstration of prosodic similarity effects in short-term memory. The implications of a prosodic similarity effect for theories of lexical representation and of dyslexia are discussed. © 2016 The Authors. Dyslexia published by John Wiley & Sons Ltd. © 2016 The Authors. Dyslexia published by John Wiley & Sons Ltd.

The effects of study task on prestimulus subsequent memory effects in the hippocampus.

Science.gov (United States)

de Chastelaine, Marianne; Rugg, Michael D

2015-11-01

Functional magnetic resonance imaging (fMRI) was employed to examine the effects of a study task manipulation on pre-stimulus activity in the hippocampus predictive of later successful recollection. Eighteen young participants were scanned while making either animacy or syllable judgments on visually presented study words. Cues presented before each word denoted which judgment should be made. Following the study phase, a surprise recognition memory test was administered in which each test item had to be endorsed as "Remembered," "Known," or "New." As expected, "deep" animacy judgments led to better memory for study items than did "shallow" syllable judgments. In both study tasks, pre-stimulus subsequent recollection effects were evident in the interval between the cue and the study item in bilateral anterior hippocampus. However, the direction of the effects differed according to the study task: whereas pre-stimulus hippocampal activity on animacy trials was greater for later recollected items than items judged old on the basis of familiarity (replicating prior findings), these effects reversed for syllable trials. We propose that the direction of pre-stimulus hippocampal subsequent memory effects depends on whether an optimal pre-stimulus task set facilitates study processing that is conducive or unconducive to the formation of contextually rich episodic memories. © 2015 Wiley Periodicals, Inc.

Copy Counts

Science.gov (United States)

Beaumont, Lee R.

1970-01-01

The level of difficulty of straight copy, which is used to measure typewriting speed, is influenced by syllable intensity (the average number of syllables per word), stroke intensity (average number of strokes per word), and high-frequency words. (CH)

Computational modeling of stuttering caused by impairments in a basal ganglia thalamo-cortical circuit involved in syllable selection and initiation

Science.gov (United States)

Civier, Oren; Bullock, Daniel; Max, Ludo; Guenther, Frank H.

2013-01-01

A typical white-matter integrity and elevated dopamine levels have been reported for individuals who stutter. We investigated how such abnormalities may lead to speech dysfluencies due to their effects on a syllable-sequencing circuit that consists of basal ganglia (BG), thalamus, and left ventral premotor cortex (vPMC). “Neurally impaired” versions of the neurocomputational speech production model GODIVA were utilized to test two hypotheses: (1) that white-matter abnormalities disturb the circuit via corticostriatal projections carrying copies of executed motor commands, and (2) that dopaminergic abnormalities disturb the circuit via the striatum. Simulation results support both hypotheses: in both scenarios, the neural abnormalities delay readout of the next syllable’s motor program, leading to dysfluency. The results also account for brain imaging findings during dysfluent speech. It is concluded that each of the two abnormality types can cause stuttering moments, probably by affecting the same BG-thalamus-vPMC circuit. PMID:23872286

[The discrimination of mono-syllable words in noise in listeners with normal hearing].

Science.gov (United States)

Yoshida, M; Sagara, T; Nagano, M; Korenaga, K; Makishima, K

1992-02-01

The discrimination of mono-syllable words (67S word-list) pronounced by a male and a female speaker was investigated in noise in 39 normal hearing subjects. The subjects listened to the test words at a constant level of 62 dB together with white or weighted noise in four S/N conditions. By processing the data with logit transformation, S/N-discrimination curves were presumed for each combination of a speech material and a noise. Regardless of the type of noise, the discrimination scores for the female voice started to decrease gradually at a S/N ratio of +10 dB, and reached 10 to 20% at-10 dB. For the male voice in white noise, the discrimination curve was similar to those for the female voice. On the contrary, the discrimination score for the male voice in weighted noise declined rapidly from a S/N ratio of +5 dB, and went below 10% at -5 dB. The discrimination curves seem to be shaped by the interrelations between the spectrum of the speech material and that of the noise.

Frequencies of inaudible high-frequency sounds differentially affect brain activity: positive and negative hypersonic effects.

Directory of Open Access Journals (Sweden)

Ariko Fukushima

Full Text Available The hypersonic effect is a phenomenon in which sounds containing significant quantities of non-stationary high-frequency components (HFCs above the human audible range (max. 20 kHz activate the midbrain and diencephalon and evoke various physiological, psychological and behavioral responses. Yet important issues remain unverified, especially the relationship existing between the frequency of HFCs and the emergence of the hypersonic effect. In this study, to investigate the relationship between the hypersonic effect and HFC frequencies, we divided an HFC (above 16 kHz of recorded gamelan music into 12 band components and applied them to subjects along with an audible component (below 16 kHz to observe changes in the alpha2 frequency component (10-13 Hz of spontaneous EEGs measured from centro-parieto-occipital regions (Alpha-2 EEG, which we previously reported as an index of the hypersonic effect. Our results showed reciprocal directional changes in Alpha-2 EEGs depending on the frequency of the HFCs presented with audible low-frequency component (LFC. When an HFC above approximately 32 kHz was applied, Alpha-2 EEG increased significantly compared to when only audible sound was applied (positive hypersonic effect, while, when an HFC below approximately 32 kHz was applied, the Alpha-2 EEG decreased (negative hypersonic effect. These findings suggest that the emergence of the hypersonic effect depends on the frequencies of inaudible HFC.

Frequencies of inaudible high-frequency sounds differentially affect brain activity: positive and negative hypersonic effects.

Science.gov (United States)

Fukushima, Ariko; Yagi, Reiko; Kawai, Norie; Honda, Manabu; Nishina, Emi; Oohashi, Tsutomu

2014-01-01

The hypersonic effect is a phenomenon in which sounds containing significant quantities of non-stationary high-frequency components (HFCs) above the human audible range (max. 20 kHz) activate the midbrain and diencephalon and evoke various physiological, psychological and behavioral responses. Yet important issues remain unverified, especially the relationship existing between the frequency of HFCs and the emergence of the hypersonic effect. In this study, to investigate the relationship between the hypersonic effect and HFC frequencies, we divided an HFC (above 16 kHz) of recorded gamelan music into 12 band components and applied them to subjects along with an audible component (below 16 kHz) to observe changes in the alpha2 frequency component (10-13 Hz) of spontaneous EEGs measured from centro-parieto-occipital regions (Alpha-2 EEG), which we previously reported as an index of the hypersonic effect. Our results showed reciprocal directional changes in Alpha-2 EEGs depending on the frequency of the HFCs presented with audible low-frequency component (LFC). When an HFC above approximately 32 kHz was applied, Alpha-2 EEG increased significantly compared to when only audible sound was applied (positive hypersonic effect), while, when an HFC below approximately 32 kHz was applied, the Alpha-2 EEG decreased (negative hypersonic effect). These findings suggest that the emergence of the hypersonic effect depends on the frequencies of inaudible HFC.

Auditory word recognition: extrinsic and intrinsic effects of word frequency.

Science.gov (United States)

Connine, C M; Titone, D; Wang, J

1993-01-01

Two experiments investigated the influence of word frequency in a phoneme identification task. Speech voicing continua were constructed so that one endpoint was a high-frequency word and the other endpoint was a low-frequency word (e.g., best-pest). Experiment 1 demonstrated that ambiguous tokens were labeled such that a high-frequency word was formed (intrinsic frequency effect). Experiment 2 manipulated the frequency composition of the list (extrinsic frequency effect). A high-frequency list bias produced an exaggerated influence of frequency; a low-frequency list bias showed a reverse frequency effect. Reaction time effects were discussed in terms of activation and postaccess decision models of frequency coding. The results support a late use of frequency in auditory word recognition.

An Objective Approach to Identify Spectral Distinctiveness for Hearing Impairment

Directory of Open Access Journals (Sweden)

Yeou-Jiunn Chen

2013-01-01

Full Text Available To facilitate the process of developing speech perception, speech-language pathologists have to teach a subject with hearing loss the differences between two syllables by manually enhancing acoustic cues of speech. However, this process is time consuming and difficult. Thus, this study proposes an objective approach to automatically identify the regions of spectral distinctiveness between two syllables, which is used for speech-perception training. To accurately represent the characteristics of speech, mel-frequency cepstrum coefficients are selected as analytical parameters. The mismatch between two syllables in time domain is handled by dynamic time warping. Further, a filter bank is adopted to estimate the components in different frequency bands, which are also represented as mel-frequency cepstrum coefficients. The spectral distinctiveness in different frequency bands is then easily estimated by using Euclidean metrics. Finally, a morphological gradient operator is applied to automatically identify the regions of spectral distinctiveness. To evaluate the proposed approach, the identified regions are manipulated and then the manipulated syllables are measured by a close-set based speech-perception test. The experimental results demonstrated that the identified regions of spectral distinctiveness are very useful in speech perception, which indeed can help speech-language pathologists in speech-perception training.

Effect of low-frequency power on dual-frequency capacitively coupled plasmas

International Nuclear Information System (INIS)

Yuan, Q H; Xin, Y; Huang, X J; Sun, K; Ning, Z Y; Yin, G Q

2008-01-01

In low-pressure dual-frequency capacitively coupled plasmas driven with 60/13.56 MHz, the effect of low-frequency power on the plasma characteristics was investigated using a compensated Langmuir electrostatic probe. At lower pressures (about 10 mTorr), it was possible to control the plasma density and the ion bombardment energy independently. As the pressure increased, this independent control could not be achieved. As the low-frequency power increased for the fixed high-frequency power, the electron energy probability function (EEPF) changed from Druyvesteyn-like to Maxwellian-like at pressures of 50 mTorr and higher, along with a drop in electron temperature. The plasma parameters were calculated and compared with simulation results.

THE RELATION OF FREQUENCY TO THE PHYSIOLOGICAL EFFECTS OF ULTRA-HIGH FREQUENCY CURRENTS.

Science.gov (United States)

Christie, R V; Loomis, A L

1929-01-31

1. Biological effects of electromagnetic waves emitted by a vacuum tube oscillator have been studied at frequencis ranging from 8,300,000 to 158,000,000 cycles per second (1.9 to 38 meters wave-length). 2. The effects produced on animals can be fully explained on the basis of the heat generated by high frequency currents which are induced in them. 3. No evidence was obtained to support the theory that certain wave-lengths have a specific action on living cells. 4. At frequencies below 50,000,000 cycles, the effect of these radiations on animals is proportionate to the intensity of the electro-magnetic field. As the frequency is increased beyond this point, the amount of induced current is diminished and the apparent lethality of the radiation is decreased. This can be explained by changes occurring in the dielectric properties of tissues at low wave-lengths.

The effects of age, viewing distance, display type, font type, colour contrast and number of syllables on the legibility of Korean characters.

Science.gov (United States)

Kong, Yong-Ku; Lee, Inseok; Jung, Myung-Chul; Song, Young-Woong

2011-05-01

This study evaluated the effects of age (20s and 60s), viewing distance (50 cm, 200 cm), display type (paper, monitor), font type (Gothic, Ming), colour contrast (black letters on white background, white letters on black background) and number of syllables (one, two) on the legibility of Korean characters by using the four legibility measures (minimum letter size for 100% correctness, maximum letter size for 0% correctness, minimum letter size for the least discomfort and maximum letter size for the most discomfort). Ten subjects in each age group read the four letters presented on a slide (letter size varied from 80 pt to 2 pt). Subjects also subjectively rated the reading discomfort of the letters on a 4-point scale (1 = no discomfort, 4 = most discomfort). According to the ANOVA procedure, age, viewing distance and font type significantly affected the four dependent variables (p fonts were smaller than the Ming fonts. Monitors were smaller than paper for correctness and maximum letter size for the most discomfort. From a comparison of the results for correctness and discomfort, people generally preferred larger letter sizes to those that they could read. The findings of this study may provide basic information for setting a global standard of letter size or font type to improve the legibility of characters written in Korean. STATEMENT OF RELEVANCE: Results obtained in this study will provide basic information and guidelines for setting standards of letter size and font type to improve the legibility of characters written in Korean. Also, the results might offer useful information for people who are working on design of visual displays.

Testing hypotheses on frequency effects in first language acquisition

DEFF Research Database (Denmark)

Kjærbæk, Laila; Basbøll, Hans

2015-01-01

On the basis of extensive literature studies, Ambridge, Kidd, Rowland and Theakston (2015) present five theses on frequency effects on language acquisition: i) the Levels and Kinds Thesis argues that frequency effects exist at all levels and are of many different kinds (e.g., type and token...... frequency effects as well as absolute and relative frequency effects); ii) the Age of Acquisition Thesis argues that all other things being equal, frequent forms will be acquired before less frequent forms. Since all other things are not equal, this claim does not entail a one-to-one relationship between...... frequency and age of acquisition; iii) the Prevent Error Thesis argues that high-frequency forms prevent (or reduce) errors in contexts in which they are the target; iv) the Cause Error Thesis argues that high-frequency forms also cause errors in contexts in which a competing, related lower-frequency form...

Frequency Effects in Second Language Acquisition: An Annotated Survey

Science.gov (United States)

Kartal, Galip; Sarigul, Ece

2017-01-01

The aim of this study is to investigate the relationship between frequency and language acquisition from many perspectives including implicit and explicit instruction, frequency effects on morpheme acquisition in L2, the relationship between frequency and multi-word constructions, frequency effects on phonetics, vocabulary, gerund and infinitive…

Parametric effects of word frequency effect in memory for mixed frequency lists

OpenAIRE

Lohnas, Lynn J.; Kahana, Michael J.

2013-01-01

The word frequency paradox refers to the finding that low frequency words are better recognized than high frequency words yet high frequency words are better recalled than low frequency words. Rather than comparing separate groups of low and high frequency words, we sought to quantify the functional relation between word frequency and memory performance across the broad range of frequencies typically used in episodic memory experiments. Here we report that both low frequency and high frequenc...

Extremely high frequency RF effects on electronics.

Energy Technology Data Exchange (ETDEWEB)

Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

2012-01-01

The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

Afrikaans Syllabification Patterns

Directory of Open Access Journals (Sweden)

Tilla Fick

2010-01-01

note that the frequency of words ending with s is even higher than for words starting with s. The two and three letter patterns that occur most are er (10% of all two letter patterns and ing (4% of all three letter patterns. In an analysis of syllables in Afrikaans words, we found that (as for complete words syllables most often start with the letter s and end with e, while the frequency of syllables ending with s is almost as high as the frequency of syllables starting with s. This indicates that problems with hyphenation can be expected around the letter s. The two and three letter syllables that occur most often are -ge- and -ver-, respectively.In an attempt to decide on the window length to use to generate training data for machine-learning techniques we also analysed the length of syllables. The results show that two and three letter syllables occur most often, but that four letter syllables have the most unique instances. We also analysed a spectrum of window configurations and found that the ideal configuration will have to be determined empirically. One major problem we identified in this study is that irregular syllabification often occurs where letter patterns include the letter s. The reasons being (i the use of the combining s when joining words, (ii almost equal frequencies of syllables starting and ending with s and (iii vague hyphe- nation rules for letter combinations containing s. To effectively address automatic syllabification in Afrikaans, it is necessary to develop more sophisticated methods to handle vagueness around the letter s. 

Magnetodielectric effect of Mn–Zn ferrite at resonant frequency

International Nuclear Information System (INIS)

Pengfei, Pan; Ning, Zhang

2016-01-01

The dielectric properties and the magnetodielectric effect in Mn–Zn ferrite at resonant frequency have been studied in this paper. Dimensional-resonance-induced abnormal dielectric spectrum was observed at f≈1 MHz. The relatively large magnetodielectric ratio of 4500% in a magnetic field of 3.5 kOe was achieved from the Mn–Zn ferrite sample with the initial permeability of 15 K at resonant frequency at room temperature. Theoretical analysis suggests that the large MD effect at resonant frequency is attributed to the enhanced magnetostriction effect. - Highlights: • Dimensional resonance was measured in dielectric spectrum at f≈1 MHz. • The MD ratio of 4500% was induced by H = 3.5 kOe at resonant frequency. • The magnetostriction effect leads to the large MD effect at resonant frequency.

Cascaded processing in written compound word production

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Raymond eBertram

2015-04-01

Full Text Available In this study we investigated the intricate interplay between central linguistic processing and peripheral motor processes during typewriting. Participants had to typewrite two-constituent (noun-noun Finnish compounds in response to picture presentation while their typing behavior was registered. As dependent measures we used writing onset time to assess what processes were completed before writing and inter-key intervals to assess what processes were going on during writing. It was found that writing onset time was determined by whole word frequency rather than constituent frequencies, indicating that compound words are retrieved as whole orthographic units before writing is initiated. In addition, we found that the length of the first syllable also affects writing onset time, indicating that the first syllable is fully prepared before writing commences. The inter-key interval results showed that linguistic planning is not fully ready before writing, but cascades into the motor execution phase. More specifically, inter-key intervals were largest at syllable and morpheme boundaries, supporting the view that additional linguistic planning takes place at these boundaries. Bigram and trigram frequency also affected inter-key intervals with shorter intervals corresponding to higher frequencies. This can be explained by stronger memory traces for frequently co-occurring letter sequences in the motor memory for typewriting. These frequency effects were even larger in the second than in the first constituent, indicating that low-level motor memory starts to become more important during the course of writing compound words. We discuss our results in the light of current models of morphological processing and written word production.

Cascaded processing in written compound word production.

Science.gov (United States)

Bertram, Raymond; Tønnessen, Finn Egil; Strömqvist, Sven; Hyönä, Jukka; Niemi, Pekka

2015-01-01

In this study we investigated the intricate interplay between central linguistic processing and peripheral motor processes during typewriting. Participants had to typewrite two-constituent (noun-noun) Finnish compounds in response to picture presentation while their typing behavior was registered. As dependent measures we used writing onset time to assess what processes were completed before writing and inter-key intervals to assess what processes were going on during writing. It was found that writing onset time was determined by whole word frequency rather than constituent frequencies, indicating that compound words are retrieved as whole orthographic units before writing is initiated. In addition, we found that the length of the first syllable also affects writing onset time, indicating that the first syllable is fully prepared before writing commences. The inter-key interval results showed that linguistic planning is not fully ready before writing, but cascades into the motor execution phase. More specifically, inter-key intervals were largest at syllable and morpheme boundaries, supporting the view that additional linguistic planning takes place at these boundaries. Bigram and trigram frequency also affected inter-key intervals with shorter intervals corresponding to higher frequencies. This can be explained by stronger memory traces for frequently co-occurring letter sequences in the motor memory for typewriting. These frequency effects were even larger in the second than in the first constituent, indicating that low-level motor memory starts to become more important during the course of writing compound words. We discuss our results in the light of current models of morphological processing and written word production.

The many places of frequency: evidence for a novel locus of the lexical frequency effect in word production.

Science.gov (United States)

Knobel, Mark; Finkbeiner, Matthew; Caramazza, Alfonso

2008-03-01

The effect of lexical frequency on language-processing tasks is exceptionally reliable. For example, pictures with higher frequency names are named faster and more accurately than those with lower frequency names. Experiments with normal participants and patients strongly suggest that this production effect arises at the level of lexical access. Further work has suggested that within lexical access this effect arises at the level of lexical representations. Here we present patient E.C. who shows an effect of lexical frequency on his nonword error rate. The best explanation of his performance is that there is an additional locus of frequency at the interface of lexical and segmental representational levels. We confirm this hypothesis by showing that only computational models with frequency at this new locus can produce a similar error pattern to that of patient E.C. Finally, in an analysis of a large group of Italian patients, we show that there exist patients who replicate E.C.'s pattern of results and others who show the complementary pattern of frequency effects on semantic error rates. Our results combined with previous findings suggest that frequency plays a role throughout the process of lexical access.

Iambic-Trochaic Law Effects among Native Speakers of Spanish and English

Directory of Open Access Journals (Sweden)

Megan Crowhurst

2016-10-01

Full Text Available The Iambic-Trochaic Law (Bolton, 1894; Hayes, 1995; Woodrow, 1909 asserts that listeners associate greater intensity with group beginnings (a loud-first preference and greater duration with group endings (a long-last preference. Hayes (1987; 1995 posits a natural connection between the prominences referred to in the ITL and the locations of stressed syllables in feet. However, not all lengthening in final positions originates with stressed syllables, and greater duration may also be associated with stress in nonfinal (trochaic positions. The research described here challenged the notion that presumptive long-last effects necessarily reflect stress-related duration patterns, and investigated the general hypothesis that the robustness of long-last effects should vary depending on the strength of the association between final positions and increased duration, whatever its source. Two ITL studies were conducted in which native speakers of Spanish and of English grouped streams of rhythmically alternating syllables in which vowel intensity and/or duration levels were varied. These languages were chosen because while they are prosodically similar, increased duration on constituent-final syllables is both more common and more salient in English than Spanish. Outcomes revealed robust loud-first effects in both language groups. Long-last effects were significantly weaker in the Spanish group when vowel duration was varied singly. However, long-last effects were present and comparable in both language groups when intensity and duration were covaried. Intensity was a more robust predictor of responses than duration. A primary conclusion was that whether or not humans’ rhythmic grouping preferences have an innate component, duration-based grouping preferences, at least, and the magnitude of intensity-based effects are shaped by listeners’ backgrounds.

Song convergence in multiple urban populations of silvereyes (Zosterops lateralis).

Science.gov (United States)

Potvin, Dominique A; Parris, Kirsten M

2012-08-01

Recent studies have revealed differences between urban and rural vocalizations of numerous bird species. These differences include frequency shifts, amplitude shifts, altered song speed, and selective meme use. If particular memes sung by urban populations are adapted to the urban soundscape, "urban-typical" calls, memes, or repertoires should be consistently used in multiple urban populations of the same species, regardless of geographic location. We tested whether songs or contact calls of silvereyes (Zosterops lateralis) might be subject to such convergent cultural evolution by comparing syllable repertoires of geographically dispersed urban and rural population pairs throughout southeastern Australia. Despite frequency and tempo differences between urban and rural calls, call repertoires were similar between habitat types. However, certain song syllables were used more frequently by birds from urban than rural populations. Partial redundancy analysis revealed that both geographic location and habitat characteristics were important predictors of syllable repertoire composition. These findings suggest convergent cultural evolution: urban populations modify both song and call syllables from their local repertoire in response to noise.

Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect

International Nuclear Information System (INIS)

Ju, S; Chae, S H; Choi, Y; Jun, S; Park, S M; Lee, S; Ji, C-H; Lee, H W

2013-01-01

This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low frequency input vibration. Moreover, bonding method of magnetoelectric laminate composite has been optimized to provide higher strain to piezoelectric material and thus obtain a higher output voltage. A proof-of-concept energy harvesting device has been fabricated and tested. Maximum open-circuit voltage of 11.2V has been obtained and output power of 0.57μW has been achieved for a 50kΩ load, when the fabricated energy harvester was hand-shaken

Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect

Science.gov (United States)

Ju, S.; Chae, S. H.; Choi, Y.; Jun, S.; Park, S. M.; Lee, S.; Lee, H. W.; Ji, C.-H.

2013-12-01

This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low frequency input vibration. Moreover, bonding method of magnetoelectric laminate composite has been optimized to provide higher strain to piezoelectric material and thus obtain a higher output voltage. A proof-of-concept energy harvesting device has been fabricated and tested. Maximum open-circuit voltage of 11.2V has been obtained and output power of 0.57μW has been achieved for a 50kΩ load, when the fabricated energy harvester was hand-shaken.

Subtlety of Ambient-Language Effects in Babbling: A Study of English- and Chinese-Learning Infants at 8, 10, and 12 Months

Science.gov (United States)

Lee, Chia-Cheng; Jhang, Yuna; Chen, Li-mei; Relyea, George; Oller, D. Kimbrough

2016-01-01

Prior research on ambient-language effects in babbling has often suggested infants produce language-specific phonological features within the first year. These results have been questioned in research failing to find such effects and challenging the positive findings on methodological grounds. We studied English- and Chinese-learning infants at 8, 10, and 12 months and found listeners could not detect ambient-language effects in the vast majority of infant utterances, but only in items deemed to be words or to contain canonical syllables that may have made them sound like words with language-specific shapes. Thus, the present research suggests the earliest ambient-language effects may be found in emerging lexical items or in utterances influenced by language-specific features of lexical items. Even the ambient-language effects for infant canonical syllables and words were very small compared with ambient-language effects for meaningless but phonotactically well-formed syllable sequences spoken by adult native speakers of English and Chinese. PMID:28496393

The locus of word frequency effects in skilled spelling-to-dictation.

Science.gov (United States)

Chua, Shi Min; Liow, Susan J Rickard

2014-01-01

In spelling-to-dictation tasks, skilled spellers consistently initiate spelling of high-frequency words faster than that of low-frequency words. Tainturier and Rapp's model of spelling shows three possible loci for this frequency effect: spoken word recognition, orthographic retrieval, and response execution of the first letter. Thus far, researchers have attributed the effect solely to orthographic retrieval without considering spoken word recognition or response execution. To investigate word frequency effects at each of these three loci, Experiment 1 involved a delayed spelling-to-dictation task and Experiment 2 involved a delayed/uncertain task. In Experiment 1, no frequency effect was found in the 1200-ms delayed condition, suggesting that response execution is not affected by word frequency. In Experiment 2, no frequency effect was found in the delayed/uncertain task that reflects the orthographic retrieval, whereas a frequency effect was found in the comparison immediate/uncertain task that reflects both spoken word recognition and orthographic retrieval. The results of this two-part study suggest that frequency effects in spoken word recognition play a substantial role in skilled spelling-to-dictation. Discrepancies between these findings and previous research, and the limitations of the present study, are discussed.

A study of frequency effects on conductivity measurements

International Nuclear Information System (INIS)

Nurul Ain Ahmad Latif; Mahmood Dollah; Mohd Khidir Kamaron; Suaib Ibrahim

2010-01-01

In eddy current testing (ET), different measurement can be carry out through the selection of the test frequency. In conductivity measurement, the selection of eddy current test frequencies permits to select the specific material properties to be measured. The test frequency selected should be sufficient high that eddy current penetration is limited only to fraction of the test material thickness. This paper describes the effects of test frequency on the conductivity measurement. This experiment done by applying different values of test frequency which is 20 kHz, 100 kHz and 1 MHz. (author)

The frequency attenuation effect in identity and associative priming.

Science.gov (United States)

Nievas, Francisco

2010-05-01

Three lexical decision experiments were carried out, where the masked priming paradigm is used to study the role of the frequency attenuation effect (more priming in low-frequency target words than in high-frequency target words) in repetition and associative priming, manipulating Prime Duration (PD) and Stimulus Onset Asynchrony (SOA). A new concept was introduced, Minimum Time Threshold (MTT), this is, the minimum time interval of exposure to the masked word in order to become aware of it. Results support the notion that MTT is a key to the appearance of the frequency attenuation effect when enough word processing time is allowed. Results do not support the unified explanation of masked priming and long-term priming as proposed by Bodner and Masson (2001). Moreover, information feedback from the semantic level was not the reason for the frequency attenuation effect in repetition priming.

Gender Identification Using High-Frequency Speech Energy: Effects of Increasing the Low-Frequency Limit.

Science.gov (United States)

Donai, Jeremy J; Halbritter, Rachel M

The purpose of this study was to investigate the ability of normal-hearing listeners to use high-frequency energy for gender identification from naturally produced speech signals. Two experiments were conducted using a repeated-measures design. Experiment 1 investigated the effects of increasing high-pass filter cutoff (i.e., increasing the low-frequency spectral limit) on gender identification from naturally produced vowel segments. Experiment 2 studied the effects of increasing high-pass filter cutoff on gender identification from naturally produced sentences. Confidence ratings for the gender identification task were also obtained for both experiments. Listeners in experiment 1 were capable of extracting talker gender information at levels significantly above chance from vowel segments high-pass filtered up to 8.5 kHz. Listeners in experiment 2 also performed above chance on the gender identification task from sentences high-pass filtered up to 12 kHz. Cumulatively, the results of both experiments provide evidence that normal-hearing listeners can utilize information from the very high-frequency region (above 4 to 5 kHz) of the speech signal for talker gender identification. These findings are at variance with current assumptions regarding the perceptual information regarding talker gender within this frequency region. The current results also corroborate and extend previous studies of the use of high-frequency speech energy for perceptual tasks. These findings have potential implications for the study of information contained within the high-frequency region of the speech spectrum and the role this region may play in navigating the auditory scene, particularly when the low-frequency portion of the spectrum is masked by environmental noise sources or for listeners with substantial hearing loss in the low-frequency region and better hearing sensitivity in the high-frequency region (i.e., reverse slope hearing loss).

The Malay Lexicon Project: a database of lexical statistics for 9,592 words.

Science.gov (United States)

Yap, Melvin J; Liow, Susan J Rickard; Jalil, Sajlia Binte; Faizal, Siti Syuhada Binte

2010-11-01

Malay, a language spoken by 250 million people, has a shallow alphabetic orthography, simple syllable structures, and transparent affixation--characteristics that contrast sharply with those of English. In the present article, we first compare the letter-phoneme and letter-syllable ratios for a sample of alphabetic orthographies to highlight the importance of separating language-specific from language-universal reading processes. Then, in order to develop a better understanding of word recognition in orthographies with more consistent mappings to phonology than English, we compiled a database of lexical variables (letter length, syllable length, phoneme length, morpheme length, word frequency, orthographic and phonological neighborhood sizes, and orthographic and phonological Levenshtein distances) for 9,592 Malay words. Separate hierarchical regression analyses for Malay and English revealed how the consistency of orthography-phonology mappings selectively modulates the effects of different lexical variables on lexical decision and speeded pronunciation performance. The database of lexical and behavioral measures for Malay is available at http://brm.psychonomic-journals.org/content/supplemental.

Anomalous Josephson Effect between Even-and Odd-Frequency Superconductors

NARCIS (Netherlands)

Tanaka, Yukio; Golubov, Alexandre Avraamovitch; Kashiwaya, Satoshi; Ueda, Masahito

2007-01-01

We demonstrate that, contrary to standard wisdom, the lowest-order Josephson coupling is possible between odd- and even-frequency superconductors. The origin of this effect is the induced odd- (even-)frequency pairing component at the interface of bulk even- (odd-)frequency superconductors. The

Reading of kana (phonetic symbols for syllables) in Japanese children with spastic diplegia and periventricular leukomalacia.

Science.gov (United States)

Yokochi, K

2000-01-01

In 31 Japanese children with spastic diplegia and periventricular leukomalacia (PVL), the age at which they could read Hiragana (phonetic symbols for syllables) and psychometric data were examined. Reading of Hiragana was achieved between 2 and 8 years of age in all subjects except one. Four children could read Hiragana at 2 to 3 years of age, an age which is considered early among Japanese children. Performance IQs of the Wechsler Scale were lower than Verbal IQs in 18 of 19 children who were administered this test, and DQs of the cognitive adaptive (C-A) area of the K-form developmental test (a popular test in Japan) were lower than those of the language social area in all 12 children taking this test. Among eight children having performance IQs or DQs of C-A less than 50, seven acquired reading ability of Hiragana at 8 years of age or below. A visuoperceptual disorder manifested by diplegic children with PVL does not affect the acquisition of Kana-reading ability.

PROCESAMIENTO DE LA PALABRA ESCRITA EN LA VEJEZ NORMAL PROCESSING OF THE WRITTEN WORD IN NORMAL AGING

Directory of Open Access Journals (Sweden)

Alba Gallo

2010-06-01

Full Text Available En esta investigación se analiza la escritura a mano de palabras aisladas en veinte adultos mayores (entre setenta y ochenta años de edad, para determinar si los efectos silábicos hallados en investigaciones previas sobre la escritura de personas jóvenes se conservan o deterioran con la edad. Se diseñaron dos experimentos y en cada uno de ellos se evaluó un efecto silábico diferente: la frecuencia silábica y los límites silábicos de las palabras, respectivamente. Los estímulos de los dos experimentos fueron presentados auditivamente a todos los participantes, quienes debían escribir una a una cada palabra escuchada sobre una tableta gráfica. Los resultados obtenidos (que fueron comparados con los datos arrojados por investigaciones previas que han evaluado los mismos efectos en personas jóvenes demuestran que los efectos silábicos relacionados con la frecuencia y los límites silábicos de las palabras se conservan con la edad, aunque los adultos mayores registran sistemáticamente tiempos de ejecución de la tarea de escritura mucho mayores que los jóvenes.This research analyzes the handwriting of isolated words in twenty elderly (between seventy and eighty years of age to determine whether the syllabic effects, found in previous studies on the handwriting of young people, are maintained or deteriorate with age. Two experiments were designed, and each one assessed a different syllabic effect: syllable frequency, and syllable boundaries of words, respectively. The stimuli of the two experiments were presented auditory to the participants, who were to write each word they heard on a graphics tablet. The results (which were compared with data collected from previous investigations that have evaluated the same effects on young people indicate that the effects related to the syllable frequency and syllable boundaries of words are preserved with age, although older adults systematically reported a larger time execution of the written

Word position and stress effects in consonant cluster perception and production.

Science.gov (United States)

Cilibrasi, Luca; Stojanovik, Vesna; Riddell, Patricia

2015-02-01

The aim of the present study was to investigate whether the saliency effect for word beginnings reported in children with dyslexia (Marshall & Van der Lely, 2009) can be found also in typically developing children. Thirty-four typically developing Italian children aged 8-10 years completed two specifically designed tasks: a production task and a perception task. Both tasks used nonwords containing clusters consisting of plosive plus liquid (e.g. pl). Clusters could be either in a stressed or in an unstressed syllable and could be either in initial position (first syllable) or in medial position (second syllable). In the production task, children were asked to repeat the nonwords. In the perception task, the children were asked to discriminate between two nonwords differing in one phoneme belonging to a cluster by reporting whether two repetitions were the same or different. Results from the production task showed that children are more accurate in repeating stressed than unstressed syllables, but there was no difference with respect to position of the cluster. Results from the perception task showed that children performed more accurately when discriminating word initial contrasts than when discriminating word medial contrasts, especially if the cluster was unstressed. Implications of this finding for clinical assessments are discussed. Copyright © 2015 John Wiley & Sons, Ltd.

Low-frequency noise in planar Hall effect bridge sensors

DEFF Research Database (Denmark)

Persson, Anders; Bejhedb, R.S.; Bejhed, R.S.

2011-01-01

The low-frequency characteristics of planar Hall effect bridge sensors are investigated as function of the sensor bias current and the applied magnetic field. The noise spectra reveal a Johnson-like spectrum at high frequencies, and a 1/f-like excess noise spectrum at lower frequencies, with a kn...

Effect of push frequency on the economy of wheelchair racers.

Science.gov (United States)

Goosey, V L; Campbell, I G; Fowler, N E

2000-01-01

The aim of the study was to examine the effect of varying push frequency on pushing economy (oxygen uptake at a given speed). Eight male wheelchair racers completed a series of exercise bouts on a wheelchair ergometer (Bromking Turbo Trainer, Bromakin, UK) at 6.58 m x s(-1). Initially, subjects self-selected their freely chosen push frequency (FCF); this was followed by 4 random trials pushing at 60, 80, 120, and 140% of this FCF. Steady state VO2 was determined using Douglas bags, and heart rate was recorded by telemetry. After each condition, a small capillary blood sample was obtained and analyzed for blood lactate concentration (BLa) and a rating of perceived exertion (RPE) was recorded. At 6.58 m x s(-1) oxygen uptake, RPE, and gross mechanical efficiency were nonlinearly related to push frequency. Analysis of variance showed a significant effect (P push frequency had little effect on HR although BLa increased linearly and was higher at the 140% FCF condition compared with 60% FCF (P push frequency increased. The start angle and end angle of hand contact were similar for conditions, whereas the range of trunk motion decreased with push frequency (P push frequency had an effect on pushing economy, and that the athletes' FCF was the most economical.

Effects of feed refreshing frequency on growth and carcass ...

African Journals Online (AJOL)

UPuser

2006) meal frequency referred to the frequency with which animals actually consume feed, not to the frequency with which animals were presented with fresh feed. The literature is inconclusive on the effect of feed refreshening on the growth performance and carcass characteristics of lambs. Therefore, the present study was ...

Evaluating cognitive models of visual word recognition using fMRI: Effects of lexical and sublexical variables.

Science.gov (United States)

Protopapas, Athanassios; Orfanidou, Eleni; Taylor, J S H; Karavasilis, Efstratios; Kapnoula, Efthymia C; Panagiotaropoulou, Georgia; Velonakis, Georgios; Poulou, Loukia S; Smyrnis, Nikolaos; Kelekis, Dimitrios

2016-03-01

In this study predictions of the dual-route cascaded (DRC) model of word reading were tested using fMRI. Specifically, patterns of co-localization were investigated: (a) between pseudoword length effects and a pseudowords vs. fixation contrast, to reveal the sublexical grapho-phonemic conversion (GPC) system; and (b) between word frequency effects and a words vs. pseudowords contrast, to reveal the orthographic and phonological lexicon. Forty four native speakers of Greek were scanned at 3T in an event-related lexical decision task with three event types: (a) 150 words in which frequency, length, bigram and syllable frequency, neighborhood, and orthographic consistency were decorrelated; (b) 150 matched pseudowords; and (c) fixation. Whole-brain analysis failed to reveal the predicted co-localizations. Further analysis with participant-specific regions of interest defined within masks from the group contrasts revealed length effects in left inferior parietal cortex and frequency effects in the left middle temporal gyrus. These findings could be interpreted as partially consistent with the existence of the GPC system and phonological lexicon of the model, respectively. However, there was no evidence in support of an orthographic lexicon, weakening overall support for the model. The results are discussed with respect to the prospect of using neuroimaging in cognitive model evaluation. Copyright © 2016 Elsevier Inc. All rights reserved.

A Study of Mexican Free-Tailed Bat Chirp Syllables: Bayesian Functional Mixed Models for Nonstationary Acoustic Time Series

KAUST Repository

Martinez, Josue G.; Bohn, Kirsten M.; Carroll, Raymond J.; Morris, Jeffrey S.

2013-01-01

We describe a new approach to analyze chirp syllables of free-tailed bats from two regions of Texas in which they are predominant: Austin and College Station. Our goal is to characterize any systematic regional differences in the mating chirps and assess whether individual bats have signature chirps. The data are analyzed by modeling spectrograms of the chirps as responses in a Bayesian functional mixed model. Given the variable chirp lengths, we compute the spectrograms on a relative time scale interpretable as the relative chirp position, using a variable window overlap based on chirp length. We use 2D wavelet transforms to capture correlation within the spectrogram in our modeling and obtain adaptive regularization of the estimates and inference for the regions-specific spectrograms. Our model includes random effect spectrograms at the bat level to account for correlation among chirps from the same bat, and to assess relative variability in chirp spectrograms within and between bats. The modeling of spectrograms using functional mixed models is a general approach for the analysis of replicated nonstationary time series, such as our acoustical signals, to relate aspects of the signals to various predictors, while accounting for between-signal structure. This can be done on raw spectrograms when all signals are of the same length, and can be done using spectrograms defined on a relative time scale for signals of variable length in settings where the idea of defining correspondence across signals based on relative position is sensible.

A Study of Mexican Free-Tailed Bat Chirp Syllables: Bayesian Functional Mixed Models for Nonstationary Acoustic Time Series

KAUST Repository

Martinez, Josue G.

2013-06-01

We describe a new approach to analyze chirp syllables of free-tailed bats from two regions of Texas in which they are predominant: Austin and College Station. Our goal is to characterize any systematic regional differences in the mating chirps and assess whether individual bats have signature chirps. The data are analyzed by modeling spectrograms of the chirps as responses in a Bayesian functional mixed model. Given the variable chirp lengths, we compute the spectrograms on a relative time scale interpretable as the relative chirp position, using a variable window overlap based on chirp length. We use 2D wavelet transforms to capture correlation within the spectrogram in our modeling and obtain adaptive regularization of the estimates and inference for the regions-specific spectrograms. Our model includes random effect spectrograms at the bat level to account for correlation among chirps from the same bat, and to assess relative variability in chirp spectrograms within and between bats. The modeling of spectrograms using functional mixed models is a general approach for the analysis of replicated nonstationary time series, such as our acoustical signals, to relate aspects of the signals to various predictors, while accounting for between-signal structure. This can be done on raw spectrograms when all signals are of the same length, and can be done using spectrograms defined on a relative time scale for signals of variable length in settings where the idea of defining correspondence across signals based on relative position is sensible.

Exploring vocal recovery after cranial nerve injury in Bengalese finches.

Science.gov (United States)

Urbano, Catherine M; Peterson, Jennifer R; Cooper, Brenton G

2013-02-08

Songbirds and humans use auditory feedback to acquire and maintain their vocalizations. The Bengalese finch (Lonchura striata domestica) is a songbird species that rapidly modifies its vocal output to adhere to an internal song memory. In this species, the left side of the bipartite vocal organ is specialized for producing louder, higher frequencies (≥2.2kHz) and denervation of the left vocal muscles eliminates these notes. Thus, the return of higher frequency notes after cranial nerve injury can be used as a measure of vocal recovery. Either the left or right side of the syrinx was denervated by resection of the tracheosyringeal portion of the hypoglossal nerve. Histologic analyses of syringeal muscle tissue showed significant muscle atrophy in the denervated side. After left nerve resection, songs were mainly composed of lower frequency syllables, but three out of five birds recovered higher frequency syllables. Right nerve resection minimally affected phonology, but it did change song syntax; syllable sequence became abnormally stereotyped after right nerve resection. Therefore, damage to the neuromuscular control of sound production resulted in reduced motor variability, and Bengalese finches are a potential model for functional vocal recovery following cranial nerve injury. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

EFFECT OF FARM SIZE AND FREQUENCY OF CUTTING ON ...

African Journals Online (AJOL)

EFFECT OF FARM SIZE AND FREQUENCY OF CUTTING ON OUTPUT OF ... the use of Ordinary Least Square (OLS) estimation technique was used in analyzing ... frequency of cutting that would produce maximum output of the vegetable as ...

Effect of Training Frequency on Maximum Expiratory Pressure

Science.gov (United States)

Anand, Supraja; El-Bashiti, Nour; Sapienza, Christine

2012-01-01

Purpose: To determine the effects of expiratory muscle strength training (EMST) frequency on maximum expiratory pressure (MEP). Method: We assigned 12 healthy participants to 2 groups of training frequency (3 days per week and 5 days per week). They completed a 4-week training program on an EMST trainer (Aspire Products, LLC). MEP was the primary…

Effective collision frequency of electrons in noble gases

International Nuclear Information System (INIS)

Baille, P.; Chang, J.-S.; Claude, A.; Yau, A.W.; Hobson, R.M.; Ogram, G.L.

1981-01-01

The electron-neutral collision frequency in the noble gases has been calculated using recent numerical results for momentum transfer cross sections by assuming a Maxwellian distribution of electron velocities. In all these gases, except for argon, good agreement is obtained with most previously published experimental and theoretical data. Mean free path, mobilities and diffusion coefficients are also calculated from the resulting effective collision frequencies. The empirical formulae are presented for an electron temperature dependence of the electron-neutral collision frequency for all noble gases up to Tsub(e) < approximately 25.000 K. (author)

The effect of near-surface convection on oscillation frequencies of stars

Science.gov (United States)

Hanasoge, Shravan

2015-08-01

Measurements of oscillation frequencies of the Sun and stars can provide important independent constraints on their internal structure and dynamics. Seismic models of these oscillations are used to connect structure and rotation of the star to its resonant frequencies, which are then compared with observations, the goal being that of minimizing the difference between the two. Even in the case of the Sun, for which structure models are highly tuned, observed frequencies show systematic deviations from modelled frequencies, a phenomenon referred to as the “surface term”. The dominant source of this systematic effect is thought to be vigorous near-surface convection, which is not well accounted for in both stellar modelling and mode-oscillation physics. Here we bring to bear the method of homogenization, applicable in the asymptotic limit of large wavelength (in comparison to the correlation scale of convection), to characterize the effect of small-scale surface convection on resonant-mode frequencies in the Sun. We show that the full oscillation equations, in the presence of temporally stationary 3-D flows, can be reduced to an effective “quiet-Sun” wave equation with altered sound speed, Brünt-Väisäla frequency and Lamb frequency. We derive the modified wave equation and relations for the appropriate averaging of three dimensional flows and thermal quantities to obtain the properties of this effective medium. Using flows obtained from three dimensional numerical simulations of near-surface convection, we quantify their effect on solar oscillation frequencies, and find that they are shifted systematically and substantially. We argue therefore that consistent interpretations of resonant frequencies must include modifications to the wave equation that effectively capture the impact of vigorous hydrodynamic convection.

Effect of echolocation behavior-related constant frequency-frequency modulation sound on the frequency tuning of inferior collicular neurons in Hipposideros armiger.

Science.gov (United States)

Tang, Jia; Fu, Zi-Ying; Wei, Chen-Xue; Chen, Qi-Cai

2015-08-01

In constant frequency-frequency modulation (CF-FM) bats, the CF-FM echolocation signals include both CF and FM components, yet the role of such complex acoustic signals in frequency resolution by bats remains unknown. Using CF and CF-FM echolocation signals as acoustic stimuli, the responses of inferior collicular (IC) neurons of Hipposideros armiger were obtained by extracellular recordings. We tested the effect of preceding CF or CF-FM sounds on the shape of the frequency tuning curves (FTCs) of IC neurons. Results showed that both CF-FM and CF sounds reduced the number of FTCs with tailed lower-frequency-side of IC neurons. However, more IC neurons experienced such conversion after adding CF-FM sound compared with CF sound. We also found that the Q 20 value of the FTC of IC neurons experienced the largest increase with the addition of CF-FM sound. Moreover, only CF-FM sound could cause an increase in the slope of the neurons' FTCs, and such increase occurred mainly in the lower-frequency edge. These results suggested that CF-FM sound could increase the accuracy of frequency analysis of echo and cut-off low-frequency elements from the habitat of bats more than CF sound.

Influência da extensão da palavra e local da ruptura na sílaba na fala de adolescentes e adultos gagos e fluentes The influence of word extension and the position of speech disruption within the syllable structure in the speech of stuttering and fluent adolescents and adults

Directory of Open Access Journals (Sweden)

Fabiola Staróbole Juste

2011-03-01

Full Text Available OBJETIVO: Verificar a influência da extensão da palavra e da posição dentro da sílaba na ocorrência de rupturas de fala em adolescentes e adultos gagos e fluentes. MÉTODOS: Participaram do estudo 120 indivíduos, de ambos os gêneros, com idades entre 12 e 49 anos e 11 meses, divididos em quatro grupos: Grupo de Pesquisa 1 (GP1 - 30 adolescentes gagos; Grupo de Pesquisa 2 (GP2 - 30 adultos gagos; Grupo Controle 1 (GC1 - 30 adolescentes fluentes; Grupo Controle 2 (GC2 - 30 adultos fluentes. Foram coletadas amostras de fala contendo 200 sílabas fluentes. Nas amostras de fala, as palavras rompidas foram analisadas quanto à sua extensão (monossílaba, dissílaba, trissílaba e polissílaba e quanto ao local da ruptura na sílaba (posição de ataque, núcleo ou coda. RESULTADOS: Quanto à extensão, os grupos de falantes gagos não apresentaram predominância de rupturas em nenhuma das possibilidades, já para os falantes fluentes, as rupturas foram mais frequentes nas palavras monossilábicas. Em relação ao local da ruptura na sílaba, os falantes gagos apresentaram ruptura principalmente na posição de ataque, enquanto os fluentes apresentaram mais rupturas em posição de núcleo. CONCLUSÃO: De maneira geral, esses resultados sugerem que as rupturas de fala ocorrem no início das palavras e sílabas, indicando uma dificuldade na temporalização entre as velocidades de seleção e ativação fonológica, que ocorre independentemente da extensão da palavra.PURPOSE: To verify the influence of word extension and the position of speech disruption within the syllable structure in the speech of stuttering and fluent adolescents and adults. METHODS: Participants were 120 individuals of both genders, with ages between 12 and 49 years and 11 months, who were divided into four groups: Research Group 1 (RG1 - 30 adolescents who stutter; Research Group 2 (RG2 - 30 adults who stutter; Control Group 1 (CG1 - 30 adolescents who do not stutter

An acoustical study of English word stress produced by Americans and Koreans

Science.gov (United States)

Yang, Byunggon

2002-05-01

Acoustical correlates of stress can be divided into duration, intensity, and fundamental frequency. This study examined the acoustical difference in the first two syllables of stressed English words produced by ten American and Korean speakers. The Korean subjects scored very high in TOEFL. They read, at a normal speed, a fable from which the acoustical parameters of eight words were analyzed. In order to make the data comparison meaningful, each parameter was collected at 100 dynamic time points proportional to the total duration of the two syllables. Then, the ratio of the parameter sum of the first rime to that of the second rime was calculated to determine the relative prominence of the syllables. Results showed that the durations of the first two syllables were almost comparable between the Americans and Koreans. However, statistically significant differences showed up in the diphthong pronunciations and in the words with the second syllable stressed. Also, remarkably high r-squared values were found between pairs of the three acoustical parameters, which suggests that either one or a combination of two or more parameters may account for the prominence of a syllable within a word. [Work supported by Korea Science Foundation R01-1999-00229.

Frequency Response of Graphene Electrolyte-Gated Field-Effect Transistors

Directory of Open Access Journals (Sweden)

Charles Mackin

2018-02-01

Full Text Available This work develops the first frequency-dependent small-signal model for graphene electrolyte-gated field-effect transistors (EGFETs. Graphene EGFETs are microfabricated to measure intrinsic voltage gain, frequency response, and to develop a frequency-dependent small-signal model. The transfer function of the graphene EGFET small-signal model is found to contain a unique pole due to a resistive element, which stems from electrolyte gating. Intrinsic voltage gain, cutoff frequency, and transition frequency for the microfabricated graphene EGFETs are approximately 3.1 V/V, 1.9 kHz, and 6.9 kHz, respectively. This work marks a critical step in the development of high-speed chemical and biological sensors using graphene EGFETs.

La sílaba en la producción del habla de individuos con afasia de Broca The syllable in production of speech for individuals with Broca's aphasia

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Hernán Martínez Matos

2008-12-01

Full Text Available OBJETIVOS: analizar los sonidos [+ líquidos] en dos tipos de estructura silábica en la producción de habla de 35 hablantes de español con afasia de Broca con el fin de determinar si dichas estructuras se conservan o se pierden. MÉTODOS: se utilizó una muestra de habla obtenida a partir de conversaciones grabadas con 35 pacientes, 12 hombres y 23 mujeres, con afasia de Broca. A partir de esa muestra se seleccionaron las producciones silábicas de estructura CCV y de estructura CV para determinar las frecuencias respectivas y los posibles errores o sustituciones de fonemas. RESULTADOS: del total de estructuras silábicas analizadas ninguna mostró una estructura diferente a la de la sílaba española. Tanto la estructura CCV como la CV se han mantenido en la muestra de habla afásica analizada. Ninguno de los errores observados contiene secuencias de sonidos mal formadas. CONCLUSIONES: independientemente de los procesos de reducción, asimilación, sustitución, elisión de segmentos, se ha podido determinar que en la producción de habla de los sujetos afásicos hay un gran apego a la estructura silábica. Se sugiere, además, que la sílaba es una unidad funcional que se codifica en el nivel de programación fonética.PURPOSE: to analyze the [+liquid] phonemes in two types of syllabic structure in production of speech of 35 Venezuelan subjects whit Broca's aphasia, with the purpose of determining if these structures are conserved or lost. METHODS: a sample of speech was used. It was obtained from conversations recorded with the subjects, 12 men and 23 women. From that sample, the syllabic productions with CCV and CV structure were selected in order to determine the frequencies and the possible errors or substitutions. RESULTS: from the total of analyzed syllabic structures, all of them showed a similar structure to the Spanish syllable. The CCV and CV structures were maintained. None of the observed errors contained sequences of badly

Effects on Performance and Work Quality due to Low Frequency Ventilation Noise

Science.gov (United States)

Persson Waye, K.; Rylander, R.; Benton, S.; Leventhall, H. G.

1997-08-01

A pilot study was carried out to assess method evaluating effects of low frequency noise on performance. Of special interest was to study objective and subjective effects over time. Two ventilation noises were used, one of a predominantly mid frequency character and the other of a predominantly low frequency character. Both had an NC value of 35. For the study, 50 students were recruited and 30 selected on the basis of subjective reports of pressure on the eardrum after exposure to a low frequency noise. Of these, 14 randomly selected subjects aged 21 and 34 took part. The subjects performed three computerized cognitive tests in the mid frequency or the low frequency noise condition alternatively. Tests I and II were performed together with a secondary task.Questionnaires were used to evaluate subjective symptoms, effects on mood and estimated interference with the test results due to temperature, light and noise. The results showed that the subjective estimations of noise interference with performance were higher for the low frequency noise (psocial orientation (pstudied. The results further indicate that the NC curves do not fully assess the negative effects of low frequency noise on work performance.

[Acoustic characteristics of adductor spasmodic dysphonia].

Science.gov (United States)

Yang, Yang; Wang, Li-Ping

2008-06-01

To explore the acoustic characteristics of adductor spasmodic dysphonia. The acoustic characteristics, including acoustic signal of recorded voice, three-dimensional sonogram patterns and subjective assessment of voice, between 10 patients (7 women, 3 men) with adductor spasmodic dysphonia and 10 healthy volunteers (5 women, 5 men), were compared. The main clinical manifestation of adductor spasmodic dysphonia included the disorders of sound quality, rhyme and fluency. It demonstrated the tension dysphonia when reading, acoustic jitter, momentary fluctuation of frequency and volume, voice squeezing, interruption, voice prolongation, and losing normal chime. Among 10 patients, there were 1 mild dysphonia (abnormal syllable number dysphonia (abnormal syllable number 25%-49%), 1 severe dysphonia (abnormal syllable number 50%-74%) and 2 extremely severe dysphonia (abnormal syllable number > or = 75%). The average reading time in 10 patients was 49 s, with reading time extension and aphasia area interruption in acoustic signals, whereas the average reading time in health control group was 30 s, without voice interruption. The aphasia ratio averaged 42%. The respective symptom syllable in different patients demonstrated in the three-dimensional sonogram. There were voice onset time prolongation, irregular, interrupted and even absent vowel formants. The consonant of symptom syllables displayed absence or prolongation of friction murmur in the block-friction murmur occasionally. The acoustic characteristics of adductor spasmodic dysphonia is the disorders of sound quality, rhyme and fluency. The three-dimensional sonogram of the symptom syllables show distinctive changes of proportional vowels or consonant phonemes.

Effect of feeding frequencies on growth performance of Clarias ...

African Journals Online (AJOL)

Effect of feeding frequencies on growth performance of Clarias gariepinus. CI Ayo-Olalusi, AAA Ugwumba. Abstract. Investigations were carried out on the growth performance of juvenile Clarias gariepinus using four different feeding frequencies. Two hundred and forty juveniles (8.6 +0.0 g) were stocked in eight aquaria ...

Priming effects in early readers. A quantitative study of children's response times in visual lexical decision-making in their first and second language.

OpenAIRE

Fitjar, Camilla Lausund

2016-01-01

Master's thesis in Literacy studies This thesis investigates the effects of various conditions of open priming on children in a series of lexical decision tasks in their first and second language. The primes are related through meaning and/or form to the target words in the experiments. The five conditions used are same word priming, meaning-related, shared first syllable, shared last syllable or unrelated. In addition, the experiment consists of 50% pseudo-words. There are two experim...

Statistical language learning in neonates revealed by event-related brain potentials

Directory of Open Access Journals (Sweden)

Näätänen Risto

2009-03-01

Full Text Available Abstract Background Statistical learning is a candidate for one of the basic prerequisites underlying the expeditious acquisition of spoken language. Infants from 8 months of age exhibit this form of learning to segment fluent speech into distinct words. To test the statistical learning skills at birth, we recorded event-related brain responses of sleeping neonates while they were listening to a stream of syllables containing statistical cues to word boundaries. Results We found evidence that sleeping neonates are able to automatically extract statistical properties of the speech input and thus detect the word boundaries in a continuous stream of syllables containing no morphological cues. Syllable-specific event-related brain responses found in two separate studies demonstrated that the neonatal brain treated the syllables differently according to their position within pseudowords. Conclusion These results demonstrate that neonates can efficiently learn transitional probabilities or frequencies of co-occurrence between different syllables, enabling them to detect word boundaries and in this way isolate single words out of fluent natural speech. The ability to adopt statistical structures from speech may play a fundamental role as one of the earliest prerequisites of language acquisition.

Typing is writing: Linguistic properties modulate typing execution.

Science.gov (United States)

Pinet, Svetlana; Ziegler, Johannes C; Alario, F-Xavier

2016-12-01

Typing is becoming our preferred way of writing. Perhaps because of the relative recency of this change, very few studies have investigated typing from a psycholinguistic perspective. In addition, and despite obvious similarities between typing and handwriting, typing research has remained rather disconnected from handwriting research. The current study aimed at bridging this gap by evaluating how typing is affected by a number of psycholinguistic variables defined at the word, syllable, and letter levels. In a writing-to-dictation task, we assessed typing performance by measuring response accuracy, onset latencies - an index of response preparation and initiation - and interkeystroke intervals (IKIs) - an index of response execution processes. The lexical and sublexical factors revealed a composite pattern of effects. Lexical frequency improved response latencies and accuracy, while bigram frequency speeded up IKIs. Sound-spelling consistency improved latencies, but had an inhibitory effect on IKI. IKIs were also longer at syllable boundaries. Together, our findings can be fit within a framework for typed production that combines the previously developed theories of spelling and typing execution. At their interface, we highlight the need for an intermediate hierarchical stage, perhaps in the form of a graphemic buffer for typing.

Phase II trial of a syllable-timed speech treatment for school-age children who stutter.

Science.gov (United States)

Andrews, Cheryl; O'Brian, Sue; Onslow, Mark; Packman, Ann; Menzies, Ross; Lowe, Robyn

2016-06-01

A recent clinical trial (Andrews et al., 2012) showed Syllable Timed Speech (STS) to be a potentially useful treatment agent for the reduction of stuttering for school-age children. The present trial investigated a modified version of this program that incorporated parent verbal contingencies. Participants were 22 stuttering children aged 6-11 years. Treatment involved training the children and their parents to use STS in conversation. Parents were also taught to use verbal contingencies in response to their child's stuttered and stutter-free speech and to praise their child's use of STS. Outcome assessments were conducted pre-treatment, at the completion of Stage 1 of the program and 6 months and 12 months after Stage 1 completion. Outcomes are reported for the 19 children who completed Stage 1 of the program. The group mean percent stuttering reduction was 77% from pre-treatment to 12 months post-treatment, and 82% with the two least responsive participants removed. There was considerable variation in response to the treatment. Eleven of the children showed reduced avoidance of speaking situations and 18 were more satisfied with their fluency post-treatment. However, there was some suggestion that stuttering control was not sufficient to fully eliminate situation avoidance for the children. The results of this trial are sufficiently encouraging to warrant further clinical trials of the method. Copyright © 2016 Elsevier Inc. All rights reserved.

Self-Voice, but Not Self-Face, Reduces the McGurk Effect

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Christopher Aruffo

2011-10-01

Full Text Available The McGurk effect represents a perceptual illusion resulting from the integration of an auditory syllable dubbed onto an incongruous visual syllable. The involuntary and impenetrable nature of the illusion is frequently used to support the multisensory nature of audiovisual speech perception. Here we show that both self-speech and familiarized speech reduce the effect. When self-speech was separated into self-voice and self-face mismatched with different faces and voices, only self-voice weakened the illusion. Thus, a familiar vocal identity automatically confers a processing advantage to multisensory speech, while a familiar facial identity does not. When another group of participants were familiarized with the speakers, participants' ability to take advantage of that familiarization was inversely correlated with their overall susceptibility to the McGurk illusion.

Effects of 415 MHz frequency on human lymphocyte genome

International Nuclear Information System (INIS)

Garaj-Vrhovac, V.; Fucic, A.; Kubelka, D.; Vojvodic, S.

1996-01-01

The continuously increasing use of artificial sources of electromagnetic radiation in industry and medicine has been accompanied in everyday life with telecommunication systems which is followed with great interest in possible hazardous effects of this type of radiation. The interesting applications of mobile telecommunications and the use of cellular phones are of topic interest. Numerous cytogenetic investigations are focused on the effects of microwave radiation from mobile communications frequency of 450 and 950 MHz on isolated cells in vitro. The aim of this work was to investigate the effects of microwaves from mobile telephone frequencies on human peripheral blood lymphocytes cultured in vitro. (author)

Mismatch negativity of sad syllables is absent in patients with major depressive disorder.

Science.gov (United States)

Pang, Xiaomei; Xu, Jing; Chang, Yi; Tang, Di; Zheng, Ya; Liu, Yanhua; Sun, Yiming

2014-01-01

Major depressive disorder (MDD) is an important and highly prevalent mental disorder characterized by anhedonia and a lack of interest in everyday activities. Additionally, patients with MDD appear to have deficits in various cognitive abilities. Although a number of studies investigating the central auditory processing of low-level sound features in patients with MDD have demonstrated that this population exhibits impairments in automatic processing, the influence of emotional voice processing has yet to be addressed. To explore the automatic processing of emotional prosodies in patients with MDD, we analyzed the ability to detect automatic changes using event-related potentials (ERPs). This study included 18 patients with MDD and 22 age- and sex-matched healthy controls. Subjects were instructed to watch a silent movie but to ignore the afferent acoustic emotional prosodies presented to both ears while continuous electroencephalographic activity was synchronously recorded. Prosodies included meaningless syllables, such as "dada" spoken with happy, angry, sad, or neutral tones. The mean amplitudes of the ERPs elicited by emotional stimuli and the peak latency of the emotional differential waveforms were analyzed. The sad MMN was absent in patients with MDD, whereas the happy and angry MMN components were similar across groups. The abnormal sad emotional MMN component was not significantly correlated with the HRSD-17 and HAMA scores, respectively. The data indicate that patients with MDD are impaired in their ability to automatically process sad prosody, whereas their ability to process happy and angry prosodies remains normal. The dysfunctional sad emotion-related MMN in patients with MDD were not correlated with depression symptoms. The blunted MMN of sad prosodies could be considered a trait of MDD.

Neurofeedback of SMR and Beta1 Frequencies: An Investigation of Learning Indices and Frequency-Specific Effects.

Science.gov (United States)

Pimenta, Miguel G; van Run, Chris; de Fockert, Jan W; Gruzelier, John H

2018-05-15

Despite evidence that Sensorimotor Rhythm (SMR) and beta1 neurofeedback have distinct cognitive enhancement effects, it remains unclear whether their amplitudes can be independently enhanced. Furthermore, demands for top-down attention control, postural restraint and maintenance of cognitive set processes, all requiring low-beta frequencies, might masquerade as learning and confound interpretation. The feasibility of selectively enhancing SMR and beta1 amplitudes was investigated with the addition of a random frequency control condition that also requires the potentially confounding cognitive processes. A comprehensive approach to assessing neurofeedback learning was undertaken through the calculation of learning indices within- and across-session and pre-to-post baseline. Herein we provide the first demonstration of beta1 within-session amplitude learning that was not attributable to extraneous cognitive processes, for it was not found with random frequency training. On the other hand, within-session SMR learning might have been obscured by high interindividual variability and methodological limitations such as the type of feedback screen, the insufficient number of sessions, and the exclusion of simultaneous theta and high-beta inhibition. Interestingly, SMR and beta1 amplitude increased across sessions in the three groups suggesting unspecific effects of neurofeedback in the low beta frequency band. Moreover, there was no clear evidence of frequency specificity associated with either SMR or beta1 training. Some methodological limitations may underpin the divergent results with previous studies. Copyright © 2017 IBRO. All rights reserved.

Strange effects of strong high-frequency excitation

DEFF Research Database (Denmark)

Thomsen, Jon Juel

2003-01-01

Three general effects of mechanical high-frequency excitation (HFE) are described: Stiffening - an apparent change in the stiffness associated with an equilibrium; Biasing - a tendency for a system to move towards a particular state which does not exist or is unstable without HFE; and Smoothening...

Magnetoelectric effect in nanogranular FeCo-MgF films at GHz frequencies

Science.gov (United States)

Ikeda, Kenji; Kobayashi, Nobukiyo; Arai, Ken-Ichi; Yabukami, Shin

2018-01-01

The magnetoelectric effect is a key issue for material science and is particularly significant in the high frequency band, where it is indispensable in industrial applications. Here, we present for the first time, a study of the high frequency tunneling magneto-dielectric (TMD) effect in nanogranular FeCo-MgF films, consisting of nanometer-sized magnetic FeCo granules dispersed in an MgF insulator matrix. Dielectric relaxation and the TMD effect are confirmed at frequencies over 10 MHz. The frequency dependence of dielectric relaxation is described by the Debye-Fröhlich model, taking relaxation time dispersion into account, which reflects variations in the nature of the microstructure, such as granule size, and the inter-spacing between the granules that affect the dielectric response. The TMD effect reaches a maximum at a frequency that is equivalent to the inverse of the relaxation time. The frequency where the peak TMD effect is observed varies between 12 MHz and 220 MHz, depending on the concentration of magnetic metal in the nanogranular films. The inter-spacing of the films decreases with increasing magnetic metal concentration, in accordance with the relaxation time. These results indicate that dielectric relaxation is controlled by changing the nanostructure, using the deposition conditions. A prospective application of these nanogranular films is in tunable impedance devices for next-generation mobile communication systems, at frequencies over 1 GHz, where capacitance is controlled using the applied magnetic field.

Effect of combined mutagenic treatments on sensitivity and mutation frequency in rice

International Nuclear Information System (INIS)

Gopinathan Nair, V.

1977-01-01

Rice seeds were subjected to two sets of combination treatments of radiations and NMH. The effects of mutagenic treatments in the M 1 and M 2 generations were recorded and discussed. Mutation frequencies estimated as number of mutations per 100 M 1 years were not higher than the values expected on the basis of additive effects. When estimated as number of mutants per 100 M 2 plants, the frequencies revealed more than additive effects. The synergistic effect on mutant frequencies was due to increase in the segregation ratio of mutants. This effect was more pronounced at the higher dose combinations of fast neutrons and NMH. (author)

Word-level prominence in Persian: An Experimental Study.

Science.gov (United States)

Sadeghi, Vahid

2017-12-01

Previous literature on the phonetics of stress in Persian has reported that fundamental frequency is the only reliable acoustic correlate of stress, and that stressed and unstressed syllables are not differentiated from each other in the absence of accentuation. In this study, the effects of lexical stress on duration, overall intensity and spectral tilt were examined in Persian both in the accented and unaccented conditions. Results showed that syllable duration is consistently affected by stress in Persian in both the accented and unaccented conditions across all vowel types. Unlike duration, the results for overall intensity and spectral tilt were significant only in the accented condition, suggesting that measures of intensity are not a correlate of stress in Persian but they are mainly caused by the presence of a pitch movement. The findings are phonologically interpreted as suggesting that word-level prominence in Persian is typologically similar to 'stress accent' languages, in which multiple phonetic cues are used to signal the prominence contrast in the accented condition, and stressed and unstressed syllables are different from each other even when the word is not pitch-accented.

Spatial Frequency Discrimination: Effects of Age, Reward, and Practice.

Directory of Open Access Journals (Sweden)

Carlijn van den Boomen

Full Text Available Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of higher spatial frequency discrimination. Secondly, it developed and validated a novel design that could be applied to improve atypically developed vision. Specifically, this study examined the effect of age and reward on task performance, practice effects, and motivation (i.e., number of trials completed in a higher spatial frequency (reference frequency: 6 cycles per degree discrimination task. We measured discrimination thresholds in children aged between 7 to 12 years and adults (N = 135. Reward was manipulated by presenting either positive reinforcement or punishment. Results showed a decrease in discrimination thresholds with age, thus revealing that higher spatial frequency discrimination continues to develop after 12 years of age. This development continues longer than previously shown for discrimination of lower spatial frequencies. Moreover, thresholds decreased during the run, indicating that discrimination abilities improved. Reward did not affect performance or improvement. However, in an additional group of 5-6 year-olds (N = 28 punishments resulted in the completion of fewer trials compared to reinforcements. In both reward conditions children aged 5-6 years completed only a fourth or half of the run (64 to 128 out of 254 trials and were not motivated to continue. The design thus needs further adaptation before it can be applied to this age group. Children aged 7-12 years and adults completed the run, suggesting that the design is successful and motivating for children aged 7-12 years. This study thus presents developmental differences in higher spatial frequency discrimination thresholds. Furthermore, it presents a design that can be

Spatial Frequency Discrimination: Effects of Age, Reward, and Practice.

Science.gov (United States)

van den Boomen, Carlijn; Peters, Judith Carolien

2017-01-01

Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of higher spatial frequency discrimination. Secondly, it developed and validated a novel design that could be applied to improve atypically developed vision. Specifically, this study examined the effect of age and reward on task performance, practice effects, and motivation (i.e., number of trials completed) in a higher spatial frequency (reference frequency: 6 cycles per degree) discrimination task. We measured discrimination thresholds in children aged between 7 to 12 years and adults (N = 135). Reward was manipulated by presenting either positive reinforcement or punishment. Results showed a decrease in discrimination thresholds with age, thus revealing that higher spatial frequency discrimination continues to develop after 12 years of age. This development continues longer than previously shown for discrimination of lower spatial frequencies. Moreover, thresholds decreased during the run, indicating that discrimination abilities improved. Reward did not affect performance or improvement. However, in an additional group of 5-6 year-olds (N = 28) punishments resulted in the completion of fewer trials compared to reinforcements. In both reward conditions children aged 5-6 years completed only a fourth or half of the run (64 to 128 out of 254 trials) and were not motivated to continue. The design thus needs further adaptation before it can be applied to this age group. Children aged 7-12 years and adults completed the run, suggesting that the design is successful and motivating for children aged 7-12 years. This study thus presents developmental differences in higher spatial frequency discrimination thresholds. Furthermore, it presents a design that can be used in future

Some considerations about frequency tuning effects in ECRIS plasmas

International Nuclear Information System (INIS)

Mascali, D.; Gammino, S.; Celona, L.; Ciavola, G.; Neri, L.; Miracoli, R.; Gambino, N.; Castro, G.; Maimone, F.

2012-01-01

In the recent past many experiments demonstrated that slight variations of the microwave frequency used for the ignition of ECRIS plasmas strongly influence their performances (frequency tuning effect) either in terms of extracted current, of mean charge state and of beam emittance. According with theoretical investigations, this phenomenon can be explained by assuming that the plasma chamber works as a resonant cavity: the excited standing waves, whose spatial structure considerably changes with the pumping frequency, globally influences either the energy absorption rate and the plasma spatial structure. The paper is followed by the slides of the presentation. (authors)

Effects of state and trait factors on nightmare frequency.

Science.gov (United States)

Schredl, Michael

2003-10-01

In a new approach, this study compared the effects of trait and state factors on nightmare frequency in a non-clinical sample. Although neuroticism and boundary thinness were related to nightmare frequency, regression analyses indicated that the trait measures did not add to the variance explained by the state measures. This finding supports the so-called continuity hypothesis of dreaming, i. e., nightmares reflect negative waking-life experiences. Second, the moderate relationship between nightmare frequency and poor sleep quality was partly explained by the day-time measures of neuroticism and stress, but it can be assumed that nightmares are an independent factor contributing to complaints of insomnia. Longitudinal studies measuring nightmare frequency and stress on a daily basis will shed light on the temporal relationship between daytime measures and the occurrence of nightmares. It will be also very interesting to study the relationship between stress and nightmare frequency in a sample who have undergone cognitive-behavioral treatment for nightmares.

Stimulus-dependent effects on right ear advantage in schizophrenia

Directory of Open Access Journals (Sweden)

Smucny J

2012-09-01

Full Text Available Jason Smucny,1,3 Korey Wylie,3 Jason Tregellas1–31Neuroscience Program, University of Colorado Anschutz Medical Campus, 2Research Science, Denver VA Medical, Center, 3Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USABackground: When presented with different sounds in each ear (dichotic listening, healthy subjects typically show a preference for stimuli heard in the right ear, an effect termed "right ear advantage". Previous studies examining right ear advantage in schizophrenia have been inconsistent, showing either decreased or increased advantage relative to comparison subjects. Given evidence for enhanced semantic processing in schizophrenia, some of this inconsistency may be due to the type of stimuli presented (words or syllables. The present study examined right ear advantage in patients and controls using both words and syllables as stimuli.Methods: Right ear advantage was compared between 20 patients with schizophrenia and 17 healthy controls. Two versions of the task were used, ie, a consonant-vowel pairing task and a fused rhymed words task.Results: A significant group × task interaction was observed. Relative to healthy controls, patients showed a greater difference on the syllable-based task compared with the word-based task. The number of distractors marked during the syllable-based task was inversely correlated with score on the Global Assessment of Function Scale.Conclusion: The findings are consistent with a left hemisphere dysfunction in schizophrenia, but also suggest that differences may be stimulus-specific, with a relative sparing of the deficit in the context of word stimuli. Performance may be related to measures of social, occupational, and psychological function.Keywords: schizophrenia, right ear advantage, dichotic, distraction

Psychophysics of the McGurk and Other Audiovisual Speech Integration Effects

Science.gov (United States)

Jiang, Jintao; Bernstein, Lynne E.

2011-01-01

When the auditory and visual components of spoken audiovisual nonsense syllables are mismatched, perceivers produce four different types of perceptual responses, auditory correct, visual correct, fusion (the so-called McGurk effect), and combination (i.e., two consonants are reported). Here, quantitative measures were developed to account for the distribution of types of perceptual responses to 384 different stimuli from four talkers. The measures included mutual information, the presented acoustic signal versus the acoustic signal recorded with the presented video, and the correlation between the presented acoustic and video stimuli. In Experiment 1, open-set perceptual responses were obtained for acoustic /bA/ or /lA/ dubbed to video /bA, dA, gA, vA, zA, lA, wA, ΔA/. The talker, the video syllable, and the acoustic syllable significantly influenced the type of response. In Experiment 2, the best predictors of response category proportions were a subset of the physical stimulus measures, with the variance accounted for in the perceptual response category proportions between 17% and 52%. That audiovisual stimulus relationships can account for response distributions supports the possibility that internal representations are based on modality-specific stimulus relationships. PMID:21574741

Handicapping: the effects of its source and frequency.

Science.gov (United States)

McElroy, James C; Crant, J Michael

2008-07-01

Using a sample of 246 working adults, the authors created a 2 x 2 x 2 experimental design to isolate the influence of performance outcome, source of handicapping, and frequency of handicapping on reactions to handicapping in organizations. Dependent measures were observers' allocations of credit/blame, interpersonal affect, and the perceived credibility of the explanation. Results showed direct effects on observer impressions for all 3 independent variables, along with a significant Source x Frequency interaction. Handicapping information presented by others yielded more favorable observer impressions than did self-handicapping, and frequent handicapping decreased observer impressions. The least credible handicapping strategy was multiple self-handicaps. A significant 3-way interaction showed that source and frequency affected perceived credibility differently, depending upon whether actual performance was a success or a failure.

Effects of dendritic load on the firing frequency of oscillating neurons.

Science.gov (United States)

Schwemmer, Michael A; Lewis, Timothy J

2011-03-01

We study the effects of passive dendritic properties on the dynamics of neuronal oscillators. We find that the addition of a passive dendrite can sometimes have counterintuitive effects on firing frequency. Specifically, the addition of a hyperpolarized passive dendritic load can either increase, decrease, or have negligible effects on firing frequency. We use the theory of weak coupling to derive phase equations for "ball-and-stick" model neurons and two-compartment model neurons. We then develop a framework for understanding how the addition of passive dendrites modulates the frequency of neuronal oscillators. We show that the average value of the neuronal oscillator's phase response curves measures the sensitivity of the neuron's firing rate to the dendritic load, including whether the addition of the dendrite causes an increase or decrease in firing frequency. We interpret this finding in terms of to the slope of the neuronal oscillator's frequency-applied current curve. We also show that equivalent results exist for constant and noisy point-source input to the dendrite. We note that the results are not specific to neurons but are applicable to any oscillator subject to a passive load.

Effect of centrifugal force on natural frequency of lateral vibration of rotating shafts

Science.gov (United States)

Behzad, M.; Bastami, A. R.

2004-07-01

This paper investigates the effect of shaft rotation on its natural frequency. Apart from gyroscopic effect, the axial force originated from centrifugal force and the Poisson effect results in change of shaft natural frequency. D'Alembert principle for shaft in cylindrical co-ordinate system, along with the stress-strain relation, gives the non-homogenous linear differential equation, which can be used to calculate axial stress in the shaft. Numerical results of this study show that axial stress produced by shaft rotation has a major effect on the natural frequency of long high-speed shafts, while shaft diameter has no influence on the results. In addition, change in lateral natural frequency due to gyroscopic effect is compared with the results of this study.

Electrosmog. Effects of high-frequency electromagnetic waves on health. Pt. 1

International Nuclear Information System (INIS)

Matthes, R.

1993-01-01

1) The concept of Electrosmog concerns technically electromagnetic waves and fields of variable frequency and intensity. In our environment, high frequency fields come almost entirely from man-made sources. 2) High frequency electromagnetic fields can cause physical effects either directly or indirectly - eg through conductive materials. Thermal effects are the most prominent. The action of force mediated by the field can cause the loadig of there electric charges in the body. 3) The amount of energy absorbed by a fabric can be calculated from the intensity of the yield and the conductivity of the material. 4) In-vitro studies have suggested that high frequency fields affect the cell membranes and can cause changes in their permeability, enzyme activity and immune responses; although there are no proven results blaming high frequency fields for such mutations, and effects on cell proliferation have not been ascertained. 5) A basic limit of O-4 W/kg has been set internationally for work-related exposure, according to public health considerations, and the limit for the general public is 0.08 W/kg. 6) These basic limits are generally kept as a minimum requirement, and generally exposure is a hot lower. When high frequency equipment is in use nearby, measures must be taken to ensure that sefety limits are upheld and injury avoided, to the eyes in particular. (orig./MG) [de

Slow high-frequency effects in mechanics: problems, solutions, potentials

DEFF Research Database (Denmark)

Thomsen, Jon Juel

2005-01-01

– an apparent change in the stiffness associated with an equilibrium; Biasing – a tendency for a system to move towards a particular state which does not exist or is unstable without HFE; and Smoothening – a tendency for discontinuities to be apparently smeared out by HFE. The effects and a method for analyzing...... and compared: The Method of Direct Separation of Motions, the Method of Averaging, and the Method of Multiple Scales. The tutorial concludes by suggesting that more vibration experts, researchers and students should know about HFE effects, for the benefit not only of general vibration troubleshooting, but also......Strong high-frequency excitation (HFE) may change the ‘slow’ (i.e. effective or average) properties of mechanical systems, e.g. their stiffness, natural frequencies, equilibriums, equilibrium stability, and bifurcation paths. This tutorial describes three general HFE effects: Stiffening...

Slow high-frequency effects in mechanics: problems, solutions, potentials

DEFF Research Database (Denmark)

Thomsen, Jon Juel

– an apparent change in the stiffness associated with an equilibrium; Biasing – a tendency for a system to move towards a particular state which does not exist or is unstable without HFE; and Smoothening – a tendency for discontinuities to be apparently smeared out by HFE. The effects and a method for analyzing...... and compared: The Method of Direct Separation of Motions, the Method of Averaging, and the Method of Multiple Scales. The tutorial concludes by suggesting that more vibration experts, researchers and students should know about HFE effects, for the benefit not only of general vibration troubleshooting, but also......Strong high-frequency excitation (HFE) may change the ‘slow’ (i.e. effective or average) properties of mechanical systems, e.g. their stiffness, natural frequencies, equilibriums, equilibrium stability, and bifurcation paths. This tutorial describes three general HFE effects: Stiffening...

Modelling switching-time effects in high-frequency power conditioning networks

Science.gov (United States)

Owen, H. A.; Sloane, T. H.; Rimer, B. H.; Wilson, T. G.

1979-01-01

Power transistor networks which switch large currents in highly inductive environments are beginning to find application in the hundred kilohertz switching frequency range. Recent developments in the fabrication of metal-oxide-semiconductor field-effect transistors in the power device category have enhanced the movement toward higher switching frequencies. Models for switching devices and of the circuits in which they are imbedded are required to properly characterize the mechanisms responsible for turning on and turning off effects. Easily interpreted results in the form of oscilloscope-like plots assist in understanding the effects of parametric studies using topology oriented computer-aided analysis methods.

Analysis of cursive letters, syllables, and words handwriting in a French second-grade child with Developmental Coordination Disorder and comparison with typically developing children.

Science.gov (United States)

Jolly, Caroline; Gentaz, Edouard

2013-01-01

Poor handwriting is a core deficit in Developmental Coordination Disorder (DCD). In a previous study, we compared the evolution of cursive letters handwriting in a girl with DCD throughout her second-grade year with that of typically developing (TD) children. We found that her handwriting evolved much less than that of TD children and remained similar to that of pre-schoolers at all stages, suggesting that her handwriting skills have reached a steady state level. We present here a continuation of this work, in which we focused on the velocity aspects of handwriting in another French child with DCD. Indeed, different velocity patterns have been observed in Chinese and English children with DCD. In the French cursive style of writing, consecutive letters are joined, a major difference with the English script style of writing. We thus analyzed the handwriting of a second-grade French girl with DCD, not only for isolated letters but also for syllables and words, in comparison to that of TD first-graders (6-7 years old; N = 85) and second-graders (7-8 years old; N = 88). Each written track was digitized, and nine kinematic parameters were measured to evaluate writing fluency. Results showed that the productions of the child with DCD were more similar to those of first-graders than to those of second-graders. In line with our previous study, the most discriminative parameters between the child with DCD and TD children were size and mean speed. Moreover, her handwriting was less fluent than that of TD children. In contrast to previous observations, we observed a higher writing velocity of the child with DCD when compared to TD children, whatever the complexity of the item, and no significant difference with TD children in the pausing time during writing. These differences may reflect linguistic specificities. For syllables and words, each letter was treated separately as a single unit, thus reflecting a problem in anticipation and automation.

Analysis of cursive letters, syllables, and words handwriting in a French second-grade child with Developmental Coordination Disorder and comparison with typically developing children

Science.gov (United States)

Jolly, Caroline; Gentaz, Edouard

2014-01-01

Poor handwriting is a core deficit in Developmental Coordination Disorder (DCD). In a previous study, we compared the evolution of cursive letters handwriting in a girl with DCD throughout her second-grade year with that of typically developing (TD) children. We found that her handwriting evolved much less than that of TD children and remained similar to that of pre-schoolers at all stages, suggesting that her handwriting skills have reached a steady state level. We present here a continuation of this work, in which we focused on the velocity aspects of handwriting in another French child with DCD. Indeed, different velocity patterns have been observed in Chinese and English children with DCD. In the French cursive style of writing, consecutive letters are joined, a major difference with the English script style of writing. We thus analyzed the handwriting of a second-grade French girl with DCD, not only for isolated letters but also for syllables and words, in comparison to that of TD first-graders (6–7 years old; N = 85) and second-graders (7–8 years old; N = 88). Each written track was digitized, and nine kinematic parameters were measured to evaluate writing fluency. Results showed that the productions of the child with DCD were more similar to those of first-graders than to those of second-graders. In line with our previous study, the most discriminative parameters between the child with DCD and TD children were size and mean speed. Moreover, her handwriting was less fluent than that of TD children. In contrast to previous observations, we observed a higher writing velocity of the child with DCD when compared to TD children, whatever the complexity of the item, and no significant difference with TD children in the pausing time during writing. These differences may reflect linguistic specificities. For syllables and words, each letter was treated separately as a single unit, thus reflecting a problem in anticipation and automation. PMID:24478735

Dissociating Word Frequency and Age of Acquisition: The Klein Effect Revived (and Reversed)

Science.gov (United States)

Dewhurst, Stephen A.; Barry, Christopher

2006-01-01

The Klein effect (G. S. Klein, 1964) refers to the finding that high-frequency words produce greater interference in a color-naming task than low-frequency words. The present study used the Klein effect to investigate the relationship between frequency and age of acquisition (AoA) by measuring their influence on color naming. Two experiments…

The subjective effect of low frequency content in road traffic noise.

Science.gov (United States)

Torija, Antonio J; Flindell, Ian H

2015-01-01

Based on subjective listening trials, Torija and Flindell [J. Acoust. Soc. Am. 135, 1-4 (2014)] observed that low frequency content in typical urban main road traffic noise appeared to make a smaller contribution to reported annoyance than might be inferred from its objective or physical dominance. This paper reports a more detailed study which was aimed at (i) identifying the difference in sound levels at which low frequency content becomes subjectively dominant over mid and high frequency content and (ii) investigating the relationship between loudness and annoyance under conditions where low frequency content is relatively more dominant, such as indoors where mid and high frequency content is reduced. The results suggested that differences of at least +30 dB between the low frequency and the mid/high frequency content are needed for changes in low frequency content to have as much subjective effect as equivalent changes in mid and high frequency content. This suggests that common criticisms of the A-frequency weighting based on a hypothesized excessive downweighting of the low frequency content may be relatively unfounded in this application area.

Effect of Ultrasonic Frequency on Lactic Acid Fermentation Promotion by Ultrasonic Irradiation

Science.gov (United States)

Shimada, Tadayuki; Ohdaira, Etsuzo; Masuzawa, Nobuyoshi

2004-05-01

The authors have been researching the promotion of lactic acid fermentation by ultrasonic irradiation. In the past research, it was proven that ultrasonic irradiation is effective in the process of fermentation, and the production of yoghurt and kefir was promoted. In this study, the effect of the ultrasonic frequency in this fermentation process was examined. In the frequency range of this study, it was found that the action of fermentation promotion was exponentially proportionate to the irradiated ultrasonic frequency.

The driving frequency effects on the atmospheric pressure corona jet plasmas from low frequency to radio frequency

International Nuclear Information System (INIS)

Kim, Dan Bee; Jung, H.; Gweon, B.; Rhee, J. K.; Choe, W.; Moon, S. Y.

2011-01-01

Lately, the atmospheric pressure jet type corona plasma, which has been typically driven by dc to low frequency (LF: several tens of kHz), is often generated by using radio frequency of 13.56 MHz. Yet, the relationship between the plasma and its driving frequency has seldom been investigated. Hence, in this study, dependence of the atmospheric pressure corona plasma characteristics on the driving frequency was explored experimentally from LF to rf (5 kHz-13.56 MHz). The plasmas generated by the driving frequency under 2 MHz were cylindrical shape of several tens of millimeters long while the 13.56 MHz plasma is spherical and a few millimeters long. As the driving frequency was increased, the plasma length became shortened. At the lower driving frequencies (below 2 MHz), the plasmas existed as positive streamer and negative glow for each half period of the applied voltage, but the discharge was more continuous in time for the 13.56 MHz plasma. It was inferred from the measured I-V curves that the higher driving frequency induced higher discharge currents, and the gas temperature was increased as the driving frequency was increased.

A Bootstrapping Model of Frequency and Context Effects in Word Learning.

Science.gov (United States)

Kachergis, George; Yu, Chen; Shiffrin, Richard M

2017-04-01

Prior research has shown that people can learn many nouns (i.e., word-object mappings) from a short series of ambiguous situations containing multiple words and objects. For successful cross-situational learning, people must approximately track which words and referents co-occur most frequently. This study investigates the effects of allowing some word-referent pairs to appear more frequently than others, as is true in real-world learning environments. Surprisingly, high-frequency pairs are not always learned better, but can also boost learning of other pairs. Using a recent associative model (Kachergis, Yu, & Shiffrin, 2012), we explain how mixing pairs of different frequencies can bootstrap late learning of the low-frequency pairs based on early learning of higher frequency pairs. We also manipulate contextual diversity, the number of pairs a given pair appears with across training, since it is naturalistically confounded with frequency. The associative model has competing familiarity and uncertainty biases, and their interaction is able to capture the individual and combined effects of frequency and contextual diversity on human learning. Two other recent word-learning models do not account for the behavioral findings. Copyright © 2016 Cognitive Science Society, Inc.

Does length or neighborhood size cause the word length effect?

Science.gov (United States)

Jalbert, Annie; Neath, Ian; Surprenant, Aimée M

2011-10-01

Jalbert, Neath, Bireta, and Surprenant (2011) suggested that past demonstrations of the word length effect, the finding that words with fewer syllables are recalled better than words with more syllables, included a confound: The short words had more orthographic neighbors than the long words. The experiments reported here test two predictions that would follow if neighborhood size is a more important factor than word length. In Experiment 1, we found that concurrent articulation removed the effect of neighborhood size, just as it removes the effect of word length. Experiment 2 demonstrated that this pattern is also found with nonwords. For Experiment 3, we factorially manipulated length and neighborhood size, and found only effects of the latter. These results are problematic for any theory of memory that includes decay offset by rehearsal, but they are consistent with accounts that include a redintegrative stage that is susceptible to disruption by noise. The results also confirm the importance of lexical and linguistic factors on memory tasks thought to tap short-term memory.

Comparison the treatment effects between simultaneous dual frequency and single frequency irradiation of ultrasound in a murine model of breast adenocarcinoma

Directory of Open Access Journals (Sweden)

Mahboobeh Alamolhoda

2010-12-01

Full Text Available Introduction: Transient cavitations induced by low frequency irradiation of ultrasound can be used to treat tumors. Previous studies in in-vitro experiments have shown that induced cavitation by dual or multiple frequencies of ultrasound is greater than induced cavitation by single frequency irradiation. In this study, we compared and evaluated the treatment effects of dual frequency irradiation of ultrasound (1 MHz and 150 kHz and single frequency irradiation in in-vivo experiments on breast adenocarcinoma tumors. Material and Method: In this study, the tumor-bearing mice were divided into 5 groups: control, sham, treated group for 30 min with 150 kHz frequency in continuous mode, another group with 1 MHz frequency in pulse mode, and treated group with combined dual frequency ultrasound (150 kHz in continuous mode and 1 MHz in 80% pulse mode. To evaluate the effects of ultrasound irradiation on tumor growth delay, the volumes of the tumors were investigated for 30 days. Tumor growth delay parameters including relative volume, inhibition ratio percentage and the required times for the tumor volume to reach to two (T2 and five (T5 times its initial volume were calculated. Results: The results showed that the treated groups with single frequency irradiation of 150 kHz continuous mode and 1 MHz pulse mode and combined dual frequency had statistically significant differences in tumor relative volume percentage during the period of 3 to 24 days after treatment (p

Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity

International Nuclear Information System (INIS)

Franco, O.S.; Paulitsch, F.S.; Pereira, A.P.C.; Teixeira, A.O.; Martins, C.N.; Silva, A.M.V.; Plentz, R.D.M.; Irigoyen, M.C.; Signori, L.U.

2014-01-01

Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia

Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity

Energy Technology Data Exchange (ETDEWEB)

Franco, O.S.; Paulitsch, F.S.; Pereira, A.P.C.; Teixeira, A.O. [Universidade Federal do Rio Grande, Faculdade de Medicina, Programa de Pós-Graduação em Ciências da Saúde, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Martins, C.N. [Universidade Federal do Rio Grande, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Fisiologia Animal Comparada, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Silva, A.M.V. [Universidade Federal de Santa Maria, Departamento de Fisioterapia e Reabilitação, Santa Maria, RS, Brasil, Departamento de Fisioterapia e Reabilitação, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Plentz, R.D.M. [Universidade Federal de Ciências da Saúde de Porto Alegre, Programa de Pós-Graduação em Ciências da Reabilitação, Programa de Pós-Graduação em Ciências da Saúde, Porto Alegre, RS, Brasil, Programa de Pós-Graduação em Ciências da Saúde, Programa de Pós-Graduação em Ciências da Reabilitação, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS (Brazil); Irigoyen, M.C. [Faculdade de Medicina, Universidade de São Paulo, Instituto do Coração, Unidade de Hipertensão, São Paulo, SP, Brasil, Unidade de Hipertensão, Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Signori, L.U. [Universidade Federal do Rio Grande, Faculdade de Medicina, Programa de Pós-Graduação em Ciências da Saúde, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Universidade Federal do Rio Grande, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Fisiologia Animal Comparada, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Universidade Federal de Santa Maria, Departamento de Fisioterapia e Reabilitação, Santa Maria, RS, Brasil, Departamento de Fisioterapia e Reabilitação, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil)

2014-04-04

Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia.

The effect of high-frequency ground motion on the MAPLE-X10 reactor

International Nuclear Information System (INIS)

Bhan, S.; Dunbar, S.

1989-06-01

The effect of high-frequency ground motion on structures and equipment in nuclear reactors is examined by subjecting simple linear models to selected recorded ground motions which exhibit low and high frequencies. Computed damage measures indicate that high-frequency short-duration ground motion, such as that observed in eastern North America, have a minimal effect on structures with low natural frequencies. Response spectra of high-frequency ground motion indicate that higher forces are induced in structures with high natural frequencies as compared to those induced by low-frequency ground motion. However, reported observations of earthquake damage in eastern North America suggest that high-frequency ground motion causes little of no damage to structures. This may be due to the energy absorption capability of structures. It is concluded that the response spectrum representative of ground motion observed in eastern North America may give an over-conservative measure of the response of structures with high natural frequencies, since it does not account for the typically observed short duration of high-frequency ground motion and for the energy absorption capability of structures. Detailed nonlinear analysis of specific structures with high natural frequencies should be performed to better predict the actual response. Recommendations for a nonlinear analysis of typical structures with high natural frequencies are made

Neighborhood Frequency Effect in Chinese Word Recognition: Evidence from Naming and Lexical Decision

Science.gov (United States)

Li, Meng-Feng; Gao, Xin-Yu; Chou, Tai-Li; Wu, Jei-Tun

2017-01-01

Neighborhood frequency is a crucial variable to know the nature of word recognition. Different from alphabetic scripts, neighborhood frequency in Chinese is usually confounded by component character frequency and neighborhood size. Three experiments were designed to explore the role of the neighborhood frequency effect in Chinese and the stimuli…

Mutational jackpot events generate effective frequency-dependent selection in adapting populations

Science.gov (United States)

Hallatschek, Oskar

The site-frequency spectrum is one the most easily measurable quantities that characterize the genetic diversity of a population. While most neutral models predict that site frequency spectra should decay with increasing frequency, a high-frequency uptick has been reported in many populations. Anomalies in the high-frequency tail are particularly unsettling because the highest frequencies can be measured with greatest accuracy. Here, we show that an uptick in the spectrum of neutral mutations generally arises when mutant frequencies are dominated by rare jackpot events, mutational events with large descendant numbers. This leads to an effective pattern of frequency-dependent selection (or unstable internal equilibrium at one half frequency) that causes an accumulation of high-frequency polymorphic sites. We reproduce the known uptick occurring for recurrent hitchhiking (genetic draft) as well as rapid adaptation, and (in the future) generalize the shape of the high-frequency tail to other scenarios that are dominated by jackpot events, such as frequent range expansions. We also tackle (in the future) the inverse approach to use the high-frequency uptick for learning about the tail of the offspring number distribution. Positively selected alleles need to surpass, typically, an u NSF Career Award (PoLS), NIH NIGMS R01, Simons Foundation.

Evaluation of high frequency ground motion effects on the seismic capacity of NPP equipments

International Nuclear Information System (INIS)

Choi, In Kil; Seo, Jeong Moon; Choun, Young Sun

2003-04-01

In this study, the uniform hazard spectrum for the example Korean nuclear power plants sites were developed and compared with various response spectra used in past seismic PRA and SMA. It shows that the high frequency ground motion effects should be considered in seismic safety evaluations. The floor response spectra were developed using the direct generation method that can develop the floor response spectra from the input response spectrum directly with only the dynamic properties of structures obtained from the design calculation. Most attachment of the equipments to the structure has a minimum distortion capacity. This makes it possible to drop the effective frequency of equipment to low frequency before it is severely damaged. The results of this study show that the high frequency ground motion effects on the floor response spectra were significant, and the effects should be considered in the SPRA and SMA for the equipments installed in a building. The high frequency ground motion effects are more important for the seismic capacity evaluation of functional failure modes. The high frequency ground motion effects on the structural failure of equipments that attached to the floor by welding can be reduced by the distortion capacity of welded anchorage

High power single-frequency and frequency-doubled laser with active compensation for the thermal lens effect of terbium gallium garnet crystal.

Science.gov (United States)

Yin, Qiwei; Lu, Huadong; Su, Jing; Peng, Kunchi

2016-05-01

The thermal lens effect of terbium gallium garnet (TGG) crystal in a high power single-frequency laser severely limits the output power and the beam quality of the laser. By inserting a potassium dideuterium phosphate (DKDP) slice with negative thermo-optical coefficient into the laser resonator, the harmful influence of the thermal lens effect of the TGG crystal can be effectively mitigated. Using this method, the stable range of the laser is broadened, the bistability phenomenon of the laser during the process of changing the pump power is completely eliminated, the highest output power of an all-solid-state continuous-wave intracavity-frequency-doubling single-frequency laser at 532 nm is enhanced to 30.2 W, and the beam quality of the laser is significantly improved.

Effects of background noise on inter-trial phase coherence and auditory N1-P2 responses to speech stimuli.

Science.gov (United States)

Koerner, Tess K; Zhang, Yang

2015-10-01

This study investigated the effects of a speech-babble background noise on inter-trial phase coherence (ITPC, also referred to as phase locking value (PLV)) and auditory event-related responses (AERP) to speech sounds. Specifically, we analyzed EEG data from 11 normal hearing subjects to examine whether ITPC can predict noise-induced variations in the obligatory N1-P2 complex response. N1-P2 amplitude and latency data were obtained for the /bu/syllable in quiet and noise listening conditions. ITPC data in delta, theta, and alpha frequency bands were calculated for the N1-P2 responses in the two passive listening conditions. Consistent with previous studies, background noise produced significant amplitude reduction and latency increase in N1 and P2, which were accompanied by significant ITPC decreases in all the three frequency bands. Correlation analyses further revealed that variations in ITPC were able to predict the amplitude and latency variations in N1-P2. The results suggest that trial-by-trial analysis of cortical neural synchrony is a valuable tool in understanding the modulatory effects of background noise on AERP measures. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of stress ratio and frequency on fatigue crack growth rate of ...

Indian Academy of Sciences (India)

Effect of stress ratio and frequency on the fatigue crack propagation of 2618 aluminium alloy–silicon carbide composite were investigated at ambient temperature. With the first set of specimens, the fatigue crack growth rates were studied at three frequencies of 1 Hz, 5 Hz and 10 Hz at a stress ratio of 0.1 whereas the effects ...

Effect of low-frequency vibrations on speckle interferometry fringes

International Nuclear Information System (INIS)

Vikram, C.S.; Pechersky, M.J.

1998-01-01

The effects of low-frequency vibrations on speckle correlation fringes have been investigated. The relatively short capture time of the camera in the low-frequency case may yield usable fringe contrast in spite of vibration. It has been shown that the fringes also shift due to the vibration. The study is in agreement with experimental observations of good-contrast correlation fringes even if the object is not on a vibration-isolated table. Some such experimental observations are also presented. copyright 1998 Society of Photo-Optical Instrumentation Engineers

Effect of electric fields on the stabilization of premixed laminar bunsen flames at low AC frequency: Bi-ionic wind effect

KAUST Repository

Kim, Minkuk

2012-03-01

The stabilization characteristics of laminar premixed bunsen flames have been investigated experimentally by applying AC electric fields at low frequency below 60. Hz together with DC in the single electrode configuration. The blowoff velocity has been measured for varying AC voltage and frequency. A transition frequency between low and high frequency regimes has been identified near 40-50. Hz, where AC electric fields have minimal effect on flame stabilization. In the low frequency regime, the blowoff velocity decreased linearly with AC voltage such that the flames became less stable. This was consistent with the DC result, implying the influence of the ionic wind effect. The variation of blowoff velocity with AC frequency showed a non-monotonic behavior in that the velocity decreased and then increased, exhibiting minimum blowoff velocity near 6-8. Hz. Based on the molecular kinetic theory, the developing degree of ionic wind was derived. By considering the ionic wind effects arising from both positive and negative ions in a flame zone, the bi-ionic wind effect successfully explained the non-monotonic behavior of blowoff velocity with AC frequency in the low frequency regime. © 2011 The Combustion Institute.

Long term stability and individual distinctiveness in captive orca vocalizations

Science.gov (United States)

Noonan, Michael; Suchak, Malini

2005-04-01

With focus on the question of signature calling in killer whales, recordings from five captive orcas (of Icelandic origin) held at Marineland of Canada were compared. For the present analysis, samples of three different call syllables were selected from recordings made five years apart and from instances in which the identity of the calling whale was unambiguous due to temporary isolation, concomitant bubbling, and/or head nodding. The Raven software package was used to ascertain the frequency range, frequency (max), duration, and timing of maximum and minimum power within each sample. For two of the three call syllables, statistically significant differences were found among the five whales for call length and for the timing of maximums and minimums (porcas are distinct from one another in ways that are stable over the course of multiple years.

The Frequency Spectral Properties of Electrode-Skin Contact Impedance on Human Head and Its Frequency-Dependent Effects on Frequency-Difference EIT in Stroke Detection from 10Hz to 1MHz.

Directory of Open Access Journals (Sweden)

Lin Yang

Full Text Available Frequency-difference electrical impedance tomography (fdEIT reconstructs frequency-dependent changes of a complex impedance distribution. It has a potential application in acute stroke detection because there are significant differences in impedance spectra between stroke lesions and normal brain tissues. However, fdEIT suffers from the influences of electrode-skin contact impedance since contact impedance varies greatly with frequency. When using fdEIT to detect stroke, it is critical to know the degree of measurement errors or image artifacts caused by contact impedance. To our knowledge, no study has systematically investigated the frequency spectral properties of electrode-skin contact impedance on human head and its frequency-dependent effects on fdEIT used in stroke detection within a wide frequency band (10 Hz-1 MHz. In this study, we first measured and analyzed the frequency spectral properties of electrode-skin contact impedance on 47 human subjects' heads within 10 Hz-1 MHz. Then, we quantified the frequency-dependent effects of contact impedance on fdEIT in stroke detection in terms of the current distribution beneath the electrodes and the contact impedance imbalance between two measuring electrodes. The results showed that the contact impedance at high frequencies (>100 kHz significantly changed the current distribution beneath the electrode, leading to nonnegligible errors in boundary voltages and artifacts in reconstructed images. The contact impedance imbalance at low frequencies (<1 kHz also caused significant measurement errors. We conclude that the contact impedance has critical frequency-dependent influences on fdEIT and further studies on reducing such influences are necessary to improve the application of fdEIT in stroke detection.

The Frequency Spectral Properties of Electrode-Skin Contact Impedance on Human Head and Its Frequency-Dependent Effects on Frequency-Difference EIT in Stroke Detection from 10Hz to 1MHz.

Science.gov (United States)

Yang, Lin; Dai, Meng; Xu, Canhua; Zhang, Ge; Li, Weichen; Fu, Feng; Shi, Xuetao; Dong, Xiuzhen

2017-01-01

Frequency-difference electrical impedance tomography (fdEIT) reconstructs frequency-dependent changes of a complex impedance distribution. It has a potential application in acute stroke detection because there are significant differences in impedance spectra between stroke lesions and normal brain tissues. However, fdEIT suffers from the influences of electrode-skin contact impedance since contact impedance varies greatly with frequency. When using fdEIT to detect stroke, it is critical to know the degree of measurement errors or image artifacts caused by contact impedance. To our knowledge, no study has systematically investigated the frequency spectral properties of electrode-skin contact impedance on human head and its frequency-dependent effects on fdEIT used in stroke detection within a wide frequency band (10 Hz-1 MHz). In this study, we first measured and analyzed the frequency spectral properties of electrode-skin contact impedance on 47 human subjects' heads within 10 Hz-1 MHz. Then, we quantified the frequency-dependent effects of contact impedance on fdEIT in stroke detection in terms of the current distribution beneath the electrodes and the contact impedance imbalance between two measuring electrodes. The results showed that the contact impedance at high frequencies (>100 kHz) significantly changed the current distribution beneath the electrode, leading to nonnegligible errors in boundary voltages and artifacts in reconstructed images. The contact impedance imbalance at low frequencies (<1 kHz) also caused significant measurement errors. We conclude that the contact impedance has critical frequency-dependent influences on fdEIT and further studies on reducing such influences are necessary to improve the application of fdEIT in stroke detection.

Localization by interaural time difference (ITD): Effects of interaural frequency mismatch

International Nuclear Information System (INIS)

Bonham, B.H.; Lewis, E.R.

1999-01-01

A commonly accepted physiological model for lateralization of low-frequency sounds by interaural time delay (ITD) stipulates that binaural comparison neurons receive input from frequency-matched channels from each ear. Here, the effects of hypothetical interaural frequency mismatches on this model are reported. For this study, the cat close-quote s auditory system peripheral to the binaural comparison neurons was represented by a neurophysiologically derived model, and binaural comparison neurons were represented by cross-correlators. The results of the study indicate that, for binaural comparison neurons receiving input from one cochlear channel from each ear, interaural CF mismatches may serve to either augment or diminish the effective difference in ipsilateral and contralateral axonal time delays from the periphery to the binaural comparison neuron. The magnitude of this increase or decrease in the effective time delay difference can be up to 400 μs for CF mismatches of 0.2 octaves or less for binaural neurons with CFs between 250 Hz and 2.5 kHz. For binaural comparison neurons with nominal CFs near 500 Hz, the 25-μs effective time delay difference caused by a 0.012-octave CF mismatch is equal to the ITD previously shown to be behaviorally sufficient for the cat to lateralize a low-frequency sound source. copyright 1999 Acoustical Society of America.

Discrimination and streaming of speech sounds based on differences in interaural and spectral cues.

Science.gov (United States)

David, Marion; Lavandier, Mathieu; Grimault, Nicolas; Oxenham, Andrew J

2017-09-01

Differences in spatial cues, including interaural time differences (ITDs), interaural level differences (ILDs) and spectral cues, can lead to stream segregation of alternating noise bursts. It is unknown how effective such cues are for streaming sounds with realistic spectro-temporal variations. In particular, it is not known whether the high-frequency spectral cues associated with elevation remain sufficiently robust under such conditions. To answer these questions, sequences of consonant-vowel tokens were generated and filtered by non-individualized head-related transfer functions to simulate the cues associated with different positions in the horizontal and median planes. A discrimination task showed that listeners could discriminate changes in interaural cues both when the stimulus remained constant and when it varied between presentations. However, discrimination of changes in spectral cues was much poorer in the presence of stimulus variability. A streaming task, based on the detection of repeated syllables in the presence of interfering syllables, revealed that listeners can use both interaural and spectral cues to segregate alternating syllable sequences, despite the large spectro-temporal differences between stimuli. However, only the full complement of spatial cues (ILDs, ITDs, and spectral cues) resulted in obligatory streaming in a task that encouraged listeners to integrate the tokens into a single stream.

Individual Alpha Peak Frequency Predicts 10 Hz Flicker Effects on Selective Attention.

Science.gov (United States)

Gulbinaite, Rasa; van Viegen, Tara; Wieling, Martijn; Cohen, Michael X; VanRullen, Rufin

2017-10-18

Rhythmic visual stimulation ("flicker") is primarily used to "tag" processing of low-level visual and high-level cognitive phenomena. However, preliminary evidence suggests that flicker may also entrain endogenous brain oscillations, thereby modulating cognitive processes supported by those brain rhythms. Here we tested the interaction between 10 Hz flicker and endogenous alpha-band (∼10 Hz) oscillations during a selective visuospatial attention task. We recorded EEG from human participants (both genders) while they performed a modified Eriksen flanker task in which distractors and targets flickered within (10 Hz) or outside (7.5 or 15 Hz) the alpha band. By using a combination of EEG source separation, time-frequency, and single-trial linear mixed-effects modeling, we demonstrate that 10 Hz flicker interfered with stimulus processing more on incongruent than congruent trials (high vs low selective attention demands). Crucially, the effect of 10 Hz flicker on task performance was predicted by the distance between 10 Hz and individual alpha peak frequency (estimated during the task). Finally, the flicker effect on task performance was more strongly predicted by EEG flicker responses during stimulus processing than during preparation for the upcoming stimulus, suggesting that 10 Hz flicker interfered more with reactive than proactive selective attention. These findings are consistent with our hypothesis that visual flicker entrained endogenous alpha-band networks, which in turn impaired task performance. Our findings also provide novel evidence for frequency-dependent exogenous modulation of cognition that is determined by the correspondence between the exogenous flicker frequency and the endogenous brain rhythms. SIGNIFICANCE STATEMENT Here we provide novel evidence that the interaction between exogenous rhythmic visual stimulation and endogenous brain rhythms can have frequency-specific behavioral effects. We show that alpha-band (10 Hz) flicker impairs stimulus

Level of Automation and Failure Frequency Effects on Simulated Lunar Lander Performance

Science.gov (United States)

Marquez, Jessica J.; Ramirez, Margarita

2014-01-01

A human-in-the-loop experiment was conducted at the NASA Ames Research Center Vertical Motion Simulator, where instrument-rated pilots completed a simulated terminal descent phase of a lunar landing. Ten pilots participated in a 2 x 2 mixed design experiment, with level of automation as the within-subjects factor and failure frequency as the between subjects factor. The two evaluated levels of automation were high (fully automated landing) and low (manual controlled landing). During test trials, participants were exposed to either a high number of failures (75% failure frequency) or low number of failures (25% failure frequency). In order to investigate the pilots' sensitivity to changes in levels of automation and failure frequency, the dependent measure selected for this experiment was accuracy of failure diagnosis, from which D Prime and Decision Criterion were derived. For each of the dependent measures, no significant difference was found for level of automation and no significant interaction was detected between level of automation and failure frequency. A significant effect was identified for failure frequency suggesting failure frequency has a significant effect on pilots' sensitivity to failure detection and diagnosis. Participants were more likely to correctly identify and diagnose failures if they experienced the higher levels of failures, regardless of level of automation

Weight and frequency effect on spinal loading in a bricklaying task

NARCIS (Netherlands)

De Looze, M. P.; Visser, B.; Houting, I.; Van Rooy, M. A G; Van Dieën, J. H.; Toussaint, H. M.

1996-01-01

In manual materials handling jobs a reduction in the weight of materials often concurs with an increase in handling frequency. The effect of weight and inversely related frequency on spinal load was studied in two bricklaying tasks: building the skin and the floor of a steel ladle. In both tasks

Demodulation Radio Frequency Interference Effects in Operational Amplifier Circuits

Science.gov (United States)

Sutu, Yue-Hong

A series of investigations have been carried out to determine RFI effects in analog circuits using monolithic integrated operational amplifiers (op amps) as active devices. The specific RFI effect investigated is how amplitude-modulated (AM) RF signals are demodulated in op amp circuits to produce undesired low frequency responses at AM-modulation frequency. The undesired demodulation responses were shown to be characterized by a second-order nonlinear transfer function. Four representative op amp types investigated were the 741 bipolar op amp, the LM10 bipolar op amp, the LF355 JFET-Bipolar op amp, and the CA081 MOS-Bipolar op amp. Two op amp circuits were investigated. The first circuit was a noninverting unity voltage gain buffer circuit. The second circuit was an inverting op amp configuration. In the second circuit, the investigation includes the effects of an RFI suppression capacitor in the feedback path. Approximately 30 units of each op amp type were tested to determine the statistical variations of RFI demodulation effects in the two op amp circuits. The Nonlinear Circuit Analysis Program, NCAP, was used to simulate the demodulation RFI response. In the simulation, the op amp was replaced with its incremental macromodel. Values of macromodel parameters were obtained from previous investigations and manufacturer's data sheets. Some key results of this work are: (1) The RFI demodulation effects are 10 to 20 dB lower in CA081 and LF355 FET-bipolar op amp than in 741 and LM10 bipolar op amp except above 40 MHz where the LM10 RFI response begins to approach that of CA081. (2) The experimental mean values for 30 741 op amps show that RFI demodulation responses in the inverting amplifier with a 27 pF feedback capacitor were suppressed from 10 to 35 dB over the RF frequency range 0.1 to 150 MHz except at 0.15 MHz where only 3.5 dB suppression was observed. (3) The NCAP program can predict RFI demodulation responses in 741 and LF355 unity gain buffer circuits

Effects of electron inertia in capacitively coupled radio frequency discharges

International Nuclear Information System (INIS)

Xiang Nong

2004-01-01

The effects of the electron inertia on the plasma and sheath dynamics in capacitively coupled rf discharges with frequency ωω pi are investigated (here, ω and ω pi are the rf frequency and bulk ion plasma frequency, respectively). It is found that the effects of the electron inertia on the plasma density and ion velocity in the quasi-neutral region depend on the ratio of the amplitudes of the discharge current I rf and ion current I B =en 0 C s (here, e is the unit charge, n 0 is the plasma density at center, and C s is the ion sound speed). If the ratio is small so that I rf /I B √(m i /m e ) (here, m i and m e are ion and electron masses, respectively), the ion and time-averaged electron densities, ion velocity, and electric fields are little affected by the electron inertia. Otherwise, the effects of the electron inertia are significant. It is also shown that the assumption that the electrons obey the Boltzmann distribution in the sheath is invalid when the electron flux flowing to the electrode is significant

The frequency effect on the fatigue crack growth rate of 304 stainless steel

International Nuclear Information System (INIS)

Shih, Y.-S.; Chen, J.-J.

1999-01-01

Under cyclic loading condition, the fatigue crack growth (FCG) rate governed by stress intensity factor and stress ratio is well known; Walker's equation, Forman's equation and Elber's equation are typical formulae to describe the fatigue crack growth rate. However, the loading frequency effect on the fatigue crack growth rate has yet to be explored. Recently, studies have focused on the loading frequency effect on some visco-elastic materials, and have provided a clearer understanding of the frequency effect on the fatigue crack growth rate. In a physical sense, knowledge about the loading frequency effect on the fatigue crack growth rate for 304 stainless steel is still lacking. James conducted a lot of experiments, and through data analysis, he concluded an evaluation equation which is based upon the experimental illustration. In this study, the physical properties of the material are used to illustrate the modification of fatigue crack growth rate, and a new formula which is based upon the modified Forman's equation, is provided. (orig.)

Phrase-Final Words in Greek Storytelling Speech: A Study on the Effect of a Culturally-Specific Prosodic Feature on Short-Term Memory.

Science.gov (United States)

Loutrari, Ariadne; Tselekidou, Freideriki; Proios, Hariklia

2018-02-27

Prosodic patterns of speech appear to make a critical contribution to memory-related processing. We considered the case of a previously unexplored prosodic feature of Greek storytelling and its effect on free recall in thirty typically developing children between the ages of 10 and 12 years, using short ecologically valid auditory stimuli. The combination of a falling pitch contour and, more notably, extensive final-syllable vowel lengthening, which gives rise to the prosodic feature in question, led to statistically significantly higher performance in comparison to neutral phrase-final prosody. Number of syllables in target words did not reveal substantial difference in performance. The current study presents a previously undocumented culturally-specific prosodic pattern and its effect on short-term memory.

Measurement of the Hall effect in semiconductors at supersonic frequencies

International Nuclear Information System (INIS)

Putyato, I.V.; Sukhanov, S.; Lezhnev, N.B.

1978-01-01

A new method of measuring the Hall effect in variable magnetic fields at super-high frequencies using slotted line is proposed. The method is applied to the measurement of the Hall effect in n-InSb samples. It is shown that the level of output signal of samples reduces with the increasing the charge carrier concentration and with decreasing the mobility. But the range of quadratic part of the dependence of the output signal power on the control current increases. It is stated that the output signal of samples does not depend on the magnetic field frequency in the range of 4-7.3 GHz

Measurement of the Hall effect in semiconductors at supersonic frequencies

Energy Technology Data Exchange (ETDEWEB)

Putyato, I V; Sukhanov, S; Lezhnev, N B [AN Tadzhikskoj SSR, Khorog. Pamirskij Biologicheskij Inst.

1978-01-01

A new method of measuring the Hall effect in variable magnetic fields at super-high frequencies using slotted line is proposed. The method is applied to the measurement of the Hall effect in n-InSb samples. It is shown that the level of output signal of samples reduces with the increasing the charge carrier concentration and with decreasing the mobility. But the range of quadratic part of the dependence of the output signal power on the control current increases. It is stated that the output signal of samples does not depend on the magnetic field frequency in the range of 4-7.3 GHz.

Effect of ion cyclotron acceleration on frequency chirping beam-driven instabilities in NSTX

International Nuclear Information System (INIS)

Ruskov, E.; Heidbrink, W.W.; Fredrickson, E.D.; Darrow, D.; Medley, S.; Gorelenkov, N.

2006-01-01

The fast-ion distribution function in the National Spherical Torus Experiment (NSTX) is modified from shot to shot while keeping the total injected power at ∼2 MW. Deuterium beams of different energy and tangency radius are injected into helium L-mode plasmas, producing a rich set of instabilities, including TAE modes, 50-100∼kHz instabilities with rapid frequency sweeps or chirps, and strong, low frequency (10-20 kHz) fishbones. The experiment was motivated by a theory that attributes frequency chirping to the formation of holes and clumps in phase space. In the theory, increasing the effective collision frequency of the fast ions that drive the instability can suppress frequency chirping. In the experiment, high-power (∼3 MW) harmonic fast wave (HHFW) heating accelerates the fast ions in an attempt to alter the effective collision frequency. Steady-frequency TAE modes excited early in the discharge are affected by the HHFW heating but there is no evidence that the chirping of 20-100 kHz modes is suppressed. (author)

Effect of Ion Cyclotron Acceleration on Frequency Chirping Beam-Driven Instabilities in NSTX

International Nuclear Information System (INIS)

Ruskov, E.; Heidbrink, W.W.; Fredrickson, E.D.; Darrow, D.; Medley, S.; Gorelenkov, N.

2006-01-01

The fast-ion distribution function in the National Spherical Torus Experiment (NSTX) is modified from shot to shot while keeping the total injected power at ∼2 MW. Deuterium beams of different energy and tangency radius are injected into helium L-mode plasmas, producing a rich set of instabilities, including TAE modes, 50-100∼kHz instabilities with rapid frequency sweeps or chirps, and strong, low frequency (10-20 kHz) fishbones. The experiment was motivated by a theory that attributes frequency chirping to the formation of holes and clumps in phase space. In the theory, increasing the effective collision frequency of the fast ions that drive the instability can suppress frequency chirping. In the experiment, high-power (∼3 MW) harmonic fast wave (HHFW) heating accelerates the fast ions in an attempt to alter the effective collision frequency. Steady-frequency TAE modes excited early in the discharge are affected by the HHFW heating but there is no evidence that the chirping of 20-100 kHz modes is suppressed. (author)

The effects of extremely low frequency magnetic fields on mutation induction in mice

Energy Technology Data Exchange (ETDEWEB)

Wilson, James W. [Department of Genetics, University of Leicester, Leicester LE1 7RH (United Kingdom); Haines, Jackie; Sienkiewicz, Zenon [Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 0RQ (United Kingdom); Dubrova, Yuri E., E-mail: yed2@le.ac.uk [Department of Genetics, University of Leicester, Leicester LE1 7RH (United Kingdom)

2015-03-15

Highlights: • The effects of 50 Hz magnetic fields on mutation induction in mice were analyzed. • The frequency of ESTR mutation was established in sperm and blood. • Exposure to 10–300 μT for 2 and 15 h did not result in mutation induction. • Mutagenic effects of 50 Hz magnetic fields are likely to be negligible. - Abstract: The growing human exposure to extremely low frequency (ELF) magnetic fields has raised a considerable concern regarding their genotoxic effects. The aim of this study was to evaluate the in vivo effects of ELF magnetic fields irradiation on mutation induction in the germline and somatic tissues of male mice. Seven week old BALB/c × CBA/Ca F{sub 1} hybrid males were exposed to 10, 100 or 300 μT of 50 Hz magnetic fields for 2 or 15 h. Using single-molecule PCR, the frequency of mutation at the mouse Expanded Simple Tandem Repeat (ESTR) locus Ms6-hm was established in sperm and blood samples of exposed and matched sham-treated males. ESTR mutation frequency was also established in sperm and blood samples taken from male mice exposed to 1 Gy of acute X-rays. The frequency of ESTR mutation in DNA samples extracted from blood of mice exposed to magnetic fields did not significantly differ from that in sham-treated controls. However, there was a marginally significant increase in mutation frequency in sperm but this was not dose-dependent. In contrast, acute exposure X-rays led to significant increases in mutation frequency in sperm and blood of exposed males. The results of our study suggest that, within the range of doses analyzed here, the in vivo mutagenic effects of ELF magnetic fields are likely to be minor if not negligible.

The effects of extremely low frequency magnetic fields on mutation induction in mice

International Nuclear Information System (INIS)

Wilson, James W.; Haines, Jackie; Sienkiewicz, Zenon; Dubrova, Yuri E.

2015-01-01

Highlights: • The effects of 50 Hz magnetic fields on mutation induction in mice were analyzed. • The frequency of ESTR mutation was established in sperm and blood. • Exposure to 10–300 μT for 2 and 15 h did not result in mutation induction. • Mutagenic effects of 50 Hz magnetic fields are likely to be negligible. - Abstract: The growing human exposure to extremely low frequency (ELF) magnetic fields has raised a considerable concern regarding their genotoxic effects. The aim of this study was to evaluate the in vivo effects of ELF magnetic fields irradiation on mutation induction in the germline and somatic tissues of male mice. Seven week old BALB/c × CBA/Ca F 1 hybrid males were exposed to 10, 100 or 300 μT of 50 Hz magnetic fields for 2 or 15 h. Using single-molecule PCR, the frequency of mutation at the mouse Expanded Simple Tandem Repeat (ESTR) locus Ms6-hm was established in sperm and blood samples of exposed and matched sham-treated males. ESTR mutation frequency was also established in sperm and blood samples taken from male mice exposed to 1 Gy of acute X-rays. The frequency of ESTR mutation in DNA samples extracted from blood of mice exposed to magnetic fields did not significantly differ from that in sham-treated controls. However, there was a marginally significant increase in mutation frequency in sperm but this was not dose-dependent. In contrast, acute exposure X-rays led to significant increases in mutation frequency in sperm and blood of exposed males. The results of our study suggest that, within the range of doses analyzed here, the in vivo mutagenic effects of ELF magnetic fields are likely to be minor if not negligible

Modeling of Temperature Effect on Modal Frequency of Concrete Beam Based on Field Monitoring Data

Directory of Open Access Journals (Sweden)

Wenchen Shan

2018-01-01

Full Text Available Temperature variation has been widely demonstrated to produce significant effect on modal frequencies that even exceed the effect of actual damage. In order to eliminate the temperature effect on modal frequency, an effective method is to construct quantitative models which accurately predict the modal frequency corresponding to temperature variation. In this paper, principal component analysis (PCA is conducted on the temperatures taken from all embedded thermocouples for extracting input parameters of regression models. Three regression-based numerical models using multiple linear regression (MLR, back-propagation neural network (BPNN, and support vector regression (SVR techniques are constructed to capture the relationships between modal frequencies and temperature distributions from measurements of a concrete beam during a period of forty days of monitoring. A comparison with respect to the performance of various optimally configured regression models has been performed on measurement data. Results indicate that the SVR exhibits a better reproduction and prediction capability than BPNN and MLR models for predicting the modal frequencies with respect to nonuniformly distributed temperatures. It is succeeded that temperature effects on modal frequencies can be effectively eliminated based on the optimally formulated SVR model.

Effect of Cilia Beat Frequency on Mucociliary Clearance

Directory of Open Access Journals (Sweden)

Sedaghat M. H.

2016-12-01

Full Text Available Background: The airway surface liquid (ASL, which is a fluid layer coating the interior epithelial surface of the bronchi and bronchiolesis, plays an important defensive role against foreign particles and chemicals entering lungs. Objective: Numerical investigation has been employed to solve two-layer model consisting of mucus layer as a viscoelastic fluid and periciliary liquid layer as a Newtonian fluid to study the effects of cilia beat frequency (CBF at various amounts of mucus properties on muco-ciliary transport problem. Methods: Hybrid finite difference-lattice Boltzmann-method (FB-LBM has been used to solve the momentum equations and to simulate cilia forces, and also the PCLmucus interface more accurately, immersed boundary method (IBM has been employed. The main contribution of the current study is to use an Oldroyd-B model as the constitutive equation of mucus. Results: Our results show that increasing CBF and decreasing mucus viscosity ratio have great effects on mucus flow, but the effect of viscosity ratio is more significant. The results also illustrate that the relation between cilia beat frequency and mean mucus velocity is almost linear and it has similar behavior at different values of viscosity ratio. Conclusion: Numerical investigation based on hybrid IB-FD-LBM has been used to study the effect of CBF at various mounts of mucus viscosity ratio on the muco-ciliary clearance. The results showed that the effect of viscosity ratio on the muco-ciliary transport process is more significant compared with CBF.

Effects of cutting frequency on alfalfa yield and yield components in ...

African Journals Online (AJOL)

Effects of cutting frequency on alfalfa yield and yield components in Songnen Plain, Northeast China. J Chen, F Tang, R Zhu, C Gao, G Di, Y Zhang. Abstract. The productivity and quality of alfalfa (Medicago sativa L.) is strongly influenced by cutting frequency (F). To clarify that the yield and quality of alfalfa if affected by F, ...

Internal oscillation frequencies and anharmonic effects for the double sine-Gordon kink

DEFF Research Database (Denmark)

Salerno, M.; Samuelsen, Mogens Rugholm

1989-01-01

A simple derivation of the small oscillation frequency around 4π-kink solutions of the double sine-Gordon equation is presented. Small corrections to these frequencies due to anharmonic effects are also numerically and analytically investigated. The analysis is based on energetic considerations...

Ionic screening effect on low-frequency drain current fluctuations in liquid-gated nanowire FETs

International Nuclear Information System (INIS)

Lu, Ming-Pei; Vire, Eric; Montès, Laurent

2015-01-01

The ionic screening effect plays an important role in determining the fundamental surface properties within liquid–semiconductor interfaces. In this study, we investigated the characteristics of low-frequency drain current noise in liquid-gated nanowire (NW) field effect transistors (FETs) to obtain physical insight into the effect of ionic screening on low-frequency current fluctuation. When the NW FET was operated close to the gate voltage corresponding to the maximum transconductance, the magnitude of the low-frequency noise for the NW exposed to a low-ionic-strength buffer (0.001 M) was approximately 70% greater than that when exposed to a high-ionic-strength buffer (0.1 M). We propose a noise model, considering the charge coupling efficiency associated with the screening competition between the electrolyte buffer and the NW, to describe the ionic screening effect on the low-frequency drain current noise in liquid-gated NW FET systems. This report not only provides a physical understanding of the ionic screening effect behind the low-frequency current noise in liquid-gated FETs but also offers useful information for developing the technology of NW FETs with liquid-gated architectures for application in bioelectronics, nanosensors, and hybrid nanoelectronics. (paper)

Frequency-dependent effects of background noise on subcortical response timing.

Science.gov (United States)

Tierney, A; Parbery-Clark, A; Skoe, E; Kraus, N

2011-12-01

The addition of background noise to an auditory signal delays brainstem response timing. This effect has been extensively documented using manual peak selection. Peak picking, however, is impractical for large-scale studies of spectrotemporally complex stimuli, and leaves open the question of whether noise-induced delays are frequency-dependent or occur across the frequency spectrum. Here we use an automated, objective method to examine phase shifts between auditory brainstem responses to a speech sound (/da/) presented with and without background noise. We predicted that shifts in neural response timing would also be reflected in frequency-specific phase shifts. Our results indicate that the addition of background noise causes phase shifts across the subcortical response spectrum (70-1000 Hz). However, this noise-induced delay is not uniform such that some frequency bands show greater shifts than others: low-frequency phase shifts (300-500 Hz) are largest during the response to the consonant-vowel formant transition (/d/), while high-frequency shifts (720-1000 Hz) predominate during the response to the steady-state vowel (/a/). Most importantly, phase shifts occurring in specific frequency bands correlate strongly with shifts in the latencies of the predominant peaks in the auditory brainstem response, while phase shifts in other frequency bands do not. This finding confirms the validity of phase shift detection as an objective measure of timing differences and reveals that this method detects noise-induced shifts in timing that may not be captured by traditional peak latency measurements. Copyright © 2011 Elsevier B.V. All rights reserved.

Spanish norms for age of acquisition, concept familiarity, lexical frequency, manipulability, typicality, and other variables for 820 words from 14 living/nonliving concepts.

Science.gov (United States)

Moreno-Martínez, F Javier; Montoro, Pedro R; Rodríguez-Rojo, Inmaculada C

2014-12-01

This article presents a new corpus of 820 words pertaining to 14 semantic categories, 7 natural (animals, body parts, insects, flowers, fruits, trees, and vegetables) and 7 man-made (buildings, clothing, furniture, kitchen utensils, musical instruments, tools, and vehicles); each word in the database was collected empirically in a previous exemplar generation study. In the present study, 152 Spanish speakers provided data for four psycholinguistic variables known to affect lexical-semantic processing in both neurologically intact and brain-damaged participants: age of acquisition, familiarity, manipulability, and typicality. Furthermore, we collected lexical frequency data derived from Internet search hits, plus three additional Spanish lexical frequency indexes. Word length, number of syllables, and the proportion of respondents citing the exemplar as a category member-which can be useful as an additional measure of typicality-are also provided. Reliability and validity indexes showed that our items display characteristics similar to those of other corpora. Overall, this new corpus of words provides a useful tool for scientists engaged in cognitive- and neuroscience-based research focused on examining language, memory, and object processing. The full set of norms can be downloaded from www.psychonomic.org/archive.

Singing-Related Activity in Anterior Forebrain of Male Zebra Finches Reflects Courtship Motivation for Target Females

Science.gov (United States)

Iwasaki, Mai; Poulsen, Thomas M.; Oka, Kotaro; Hessler, Neal A.

2013-01-01

A critical function of singing by male songbirds is to attract a female mate. Previous studies have suggested that the anterior forebrain system is involved in this courtship behavior. Neural activity in this system, including the striatal Area X, is strikingly dependent on the function of male singing. When males sing to attract a female bird rather than while alone, less variable neural activity results in less variable song spectral features, which may be attractive to the female. These characteristics of neural activity and singing thus may reflect a male's motivation for courtship. Here, we compared the variability of neural activity and song features between courtship singing directed to a female with whom a male had previously formed a pair-bond or to other females. Surprisingly, across all units, there was no clear tendency for a difference in variability of neural activity or song features between courtship of paired females, nonpaired females, or dummy females. However, across the population of recordings, there was a significant relationship between the relative variability of syllable frequency and neural activity: when syllable frequency was less variable to paired than nonpaired females, neural activity was also less variable (and vice-versa). These results show that the lower variability of neural activity and syllable frequency during directed singing is not a binary distinction from undirected singing, but can vary in intensity, possibly related to the relative preference of a male for his singing target. PMID:24312344

Biological effects of exposure to low frequency electric and magnetic fields

International Nuclear Information System (INIS)

Ahnstroem, G.

1992-10-01

The biological effects of exposure to low frequency electric and magnetic fields are reviewed with the objective of summarizing effects directly relevant to considerations of the health and safety of exposed people

The effect of feeding frequency on insulin and ghrelin responses in human subjects

DEFF Research Database (Denmark)

Solomon, Thomas; Chambers, Edward S; Jeukendrup, Asker E

2008-01-01

Recent work shows that increased meal frequency reduces ghrelin responses in sheep. Human research suggests there is an interaction between insulin and ghrelin. The effect of meal frequency on this interaction is unknown. Therefore, we investigated the effect of feeding frequency on insulin...... and ghrelin responses in human subjects. Five healthy male volunteers were recruited from the general population: age 24 (SEM 2)years, body mass 75.7 (SEM 3.2) kg and BMI 23.8 (SEM 0.8) kg/m(2). Volunteers underwent three 8-h feeding regimens: fasting (FAST); low-frequency(two) meal ingestion (LOFREQ......(MEAL)); high-frequency (twelve) meal ingestion (HIFREQ(MEAL)). Meals were equi-energetic within trials,consisting of 64% carbohydrate, 23% fat and 13% protein. Total energy intake was equal between feeding trials. Total area under the curve for serum insulin and plasma ghrelin responses did not differ between...

Explicit frequency equations of free vibration of a nonlocal Timoshenko beam with surface effects

Science.gov (United States)

Zhao, Hai-Sheng; Zhang, Yao; Lie, Seng-Tjhen

2018-02-01

Considerations of nonlocal elasticity and surface effects in micro- and nanoscale beams are both important for the accurate prediction of natural frequency. In this study, the governing equation of a nonlocal Timoshenko beam with surface effects is established by taking into account three types of boundary conditions: hinged-hinged, clamped-clamped and clamped-hinged ends. For a hinged-hinged beam, an exact and explicit natural frequency equation is obtained. However, for clamped-clamped and clamped-hinged beams, the solutions of corresponding frequency equations must be determined numerically due to their transcendental nature. Hence, the Fredholm integral equation approach coupled with a curve fitting method is employed to derive the approximate fundamental frequency equations, which can predict the frequency values with high accuracy. In short, explicit frequency equations of the Timoshenko beam for three types of boundary conditions are proposed to exhibit directly the dependence of the natural frequency on the nonlocal elasticity, surface elasticity, residual surface stress, shear deformation and rotatory inertia, avoiding the complicated numerical computation.

Word frequency influences on the list length effect and associative memory in young and older adults.

Science.gov (United States)

Badham, Stephen P; Whitney, Cora; Sanghera, Sumeet; Maylor, Elizabeth A

2017-07-01

Many studies show that age deficits in memory are smaller for information supported by pre-experimental experience. Many studies also find dissociations in memory tasks between words that occur with high and low frequencies in language, but the literature is mixed regarding the extent of word frequency effects in normal ageing. We examined whether age deficits in episodic memory could be influenced by manipulations of word frequency. In Experiment 1, young and older adults studied short and long lists of high- and low-frequency words for free recall. The list length effect (the drop in proportion recalled for longer lists) was larger in young compared to older adults and for high- compared to low-frequency words. In Experiment 2, young and older adults completed item and associative recognition memory tests with high- and low-frequency words. Age deficits were greater for associative memory than for item memory, demonstrating an age-related associative deficit. High-frequency words led to better associative memory performance whilst low-frequency words resulted in better item memory performance. In neither experiment was there any evidence for age deficits to be smaller for high- relative to low-frequency words, suggesting that word frequency effects on memory operate independently from effects due to cognitive ageing.

Trends in examination frequency and collective effective doses from computed tomography (CT) procedures in Sudan

International Nuclear Information System (INIS)

Yousif, S. B. I.

2011-01-01

This study was carried out to estimate the examination frequency and collective dose to population from CT procedures in Sudan. To calculate the annual collective dose from CT examinations a survey was done at 10 hospitals providing data of examinations frequency per day. The data of effective dose have been obtained from pervious study on effective dose per CT examination in Sudan. Then the annual examination frequency and annual collective effective dose had been calculated and discussed providing that the annual collective effective dose from CT examinations is (1482 man.Sv). The highest percentage examination frequency was for head examination (40%). The highest percentage contribution to the total collective dose from CT examinations was for abdomen examinations (32%). The calculated annual examination frequency and annual collective effective dose had been compared with the results of literature and international studies to evaluate the estimated values. The calculated annual collective dose from CT examinations is much lower comparing with the results presented in the literature. The study offers an insight on the examination frequency and the percentage of the risk from different standard radiographic examination within the country. (Author)

Tracking the time course of word-frequency effects in auditory word recognition with event-related potentials.

Science.gov (United States)

Dufour, Sophie; Brunellière, Angèle; Frauenfelder, Ulrich H

2013-04-01

Although the word-frequency effect is one of the most established findings in spoken-word recognition, the precise processing locus of this effect is still a topic of debate. In this study, we used event-related potentials (ERPs) to track the time course of the word-frequency effect. In addition, the neighborhood density effect, which is known to reflect mechanisms involved in word identification, was also examined. The ERP data showed a clear frequency effect as early as 350 ms from word onset on the P350, followed by a later effect at word offset on the late N400. A neighborhood density effect was also found at an early stage of spoken-word processing on the PMN, and at word offset on the late N400. Overall, our ERP differences for word frequency suggest that frequency affects the core processes of word identification starting from the initial phase of lexical activation and including target word selection. They thus rule out any interpretation of the word frequency effect that is limited to a purely decisional locus after word identification has been completed. Copyright © 2012 Cognitive Science Society, Inc.

Demodulation effect is observed in neurones by exposure to low frequency modulated microwaves

Energy Technology Data Exchange (ETDEWEB)

Perez-Bruzon, R N; Figols, T; Azanza, M J [Laboratorio de Magnetobiologia, Departamento de Anatomia e Histologia Humanas, Facultad de Medicina, Universidad de Zaragoza (Spain); Moral, A del, E-mail: naogit@yahoo.co [Laboratorio de Magnetismo de Solidos, Departamento de Fisica de Materia Condensada and Instituto de Ciencia de Materiales de Aragon, Universidad de Zaragoza and CSIC (Spain)

2010-01-01

Neurones exposure to a microwave (carrier f{sub c}=13.6 GHz; power P {approx_equal} 5 mW; H{sub o} {approx_equal} 0.10 Am{sup -1} = 1.25 mOe; E{sub 0} {approx_equal} 3.5 V/m; {Delta}T {approx_equal} 0.01{sup 0}C; SAR: 3.1x10{sup -3} - 5.8x10{sup -3} W/Kg) EMF amplitude modulated by ELF-AC field (frequency, f{sub m}= 0-100 Hz) shows no electrophysiological effect under the carrier MF alone, but {sup f}requency resonances: at 2, 4, 8, 12, 16, 50, 100 Hz: demodulation effect. Resonances appear when applied ELF-MF is close to a dominant characteristic frequency of the neurone impulse Fourier spectrum. This is an interesting result considering that ELF-MF modulating RF or MW in the range of human EEG could induce frequency-resonant effects on exposed human brain.

Effect of section shape on frequencies of natural oscillations of tubular springs

Science.gov (United States)

Pirogov, S. P.; Chuba, A. Yu; Cherentsov, D. A.

2018-05-01

The necessity of determining the frequencies of natural oscillations of manometric tubular springs is substantiated. Based on the mathematical model and computer program, numerical experiments were performed that allowed us to reveal the effect of geometric parameters on the frequencies of free oscillations of manometric tubular springs.

[Effects of extremely low frequency electromagnetic radiation on cardiovascular system of workers].

Science.gov (United States)

Zhao, Long-yu; Song, Chun-xiao; Yu, Duo; Liu, Xiao-liang; Guo, Jian-qiu; Wang, Chuan; Ding, Yuan-wei; Zhou, Hong-xia; Ma, Shu-mei; Liu, Xiao-dong; Liu, Xin

2012-03-01

To observe the exposure levels of extremely low frequency electromagnetic fields in workplaces and to analyze the effects of extremely low frequency electromagnetic radiation on cardiovascular system of occupationally exposed people. Intensity of electromagnetic fields in two workplaces (control and exposure groups) was detected with EFA-300 frequency electromagnetic field strength tester, and intensity of the noise was detected with AWA5610D integral sound level. The information of health physical indicators of 188 controls and 642 occupationally exposed workers was collected. Data were analyzed by SPSS17.0 statistic software. The intensity of electric fields and the magnetic fields in exposure groups was significantly higher than that in control group (P 0.05). The results of physical examination showed that the abnormal rates of HCY, ALT, AST, GGT, ECG in the exposure group were significantly higher than those in control group (P 0.05). Exposure to extremely low frequency electromagnetic radiation may have some effects on the cardiovascular system of workers.

Effect of pulse frequency variation in laser welding of stainless steel

International Nuclear Information System (INIS)

Ahmed, E.; Manzoor, T.; Hussain, N.

2007-01-01

A parametric investigation by variations of frequencies was conducted to evaluate their effect on microstructural changes in the fusion and heat affected zones. Ferrite plus martensite microstructure was developed in these regions with visible grain coarsening in the fusion zone. The grain coarsening possibly be due to poor heat conductivity in this region. The morphology and volume fraction of martensite was changed with an increase in the frequency. At lower frequency the martensite laths and grain boundary growth was progressively changed to a network, forming connectivity of martensite and decreasing its volume fraction. The restricted growth of martensite particles to the grain boundaries for connectivity of martensite is little effective in raising the hardness of the fusion zone. An increase in the hardness ratio of fusion to heat affected zones with connected martensite particles indicates that hardness loss due to grain coarsening is compensated to some extent. (author)

Effective deep brain stimulation suppresses low frequency network oscillations in the basal ganglia by regularizing neural firing patterns

Science.gov (United States)

McConnell, George C.; So, Rosa Q.; Hilliard, Justin D; Lopomo, Paola; Grill, Warren M.

2012-01-01

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for the motor symptoms of Parkinson’s disease (PD). The effects of DBS depend strongly on stimulation frequency: high frequencies (>90Hz) improve motor symptoms, while low frequencies (basal ganglia were studied in the unilateral 6-hydroxydopamine lesioned rat model of PD. Only high frequency DBS reversed motor symptoms and the effectiveness of DBS depended strongly on stimulation frequency in a manner reminiscent of its clinical effects in persons with PD. Quantification of single-unit activity in the globus pallidus externa (GPe) and substantia nigra reticulata (SNr) revealed that high frequency DBS, but not low frequency DBS, reduced pathological low frequency oscillations (~9Hz) and entrained neurons to fire at the stimulation frequency. Similarly, the coherence between simultaneously recorded pairs of neurons within and across GPe and SNr shifted from the pathological low frequency band to the stimulation frequency during high frequency DBS, but not during low frequency DBS. The changes in firing patterns in basal ganglia neurons were not correlated with changes in firing rate. These results indicate that high frequency DBS is more effective than low frequency DBS, not as a result of changes in firing rate, but rather due to its ability to replace pathological low frequency network oscillations with a regularized pattern of neuronal firing. PMID:23136407

Effective deep brain stimulation suppresses low-frequency network oscillations in the basal ganglia by regularizing neural firing patterns.

Science.gov (United States)

McConnell, George C; So, Rosa Q; Hilliard, Justin D; Lopomo, Paola; Grill, Warren M

2012-11-07

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for the motor symptoms of Parkinson's disease (PD). The effects of DBS depend strongly on stimulation frequency: high frequencies (>90 Hz) improve motor symptoms, while low frequencies (basal ganglia were studied in the unilateral 6-hydroxydopamine lesioned rat model of PD. Only high-frequency DBS reversed motor symptoms, and the effectiveness of DBS depended strongly on stimulation frequency in a manner reminiscent of its clinical effects in persons with PD. Quantification of single-unit activity in the globus pallidus externa (GPe) and substantia nigra reticulata (SNr) revealed that high-frequency DBS, but not low-frequency DBS, reduced pathological low-frequency oscillations (∼9 Hz) and entrained neurons to fire at the stimulation frequency. Similarly, the coherence between simultaneously recorded pairs of neurons within and across GPe and SNr shifted from the pathological low-frequency band to the stimulation frequency during high-frequency DBS, but not during low-frequency DBS. The changes in firing patterns in basal ganglia neurons were not correlated with changes in firing rate. These results indicate that high-frequency DBS is more effective than low-frequency DBS, not as a result of changes in firing rate, but rather due to its ability to replace pathological low-frequency network oscillations with a regularized pattern of neuronal firing.

The Effect of Word Meaning on Speech DysFluency in Adults with Developmental Stuttering

Directory of Open Access Journals (Sweden)

Elham Masumi

2013-10-01

Full Text Available Objectives: Stuttering is one of the most prevalent speech and language disorders. Symptomology of stuttering has been surveyed from different aspects such as biological, developmental, environmental, emotional, learning and linguistic. Previous researches in English-speaking people have suggested that some linguistic features such as word meanings may play a role in the frequency of speech non-fluency in people who stutter. The aim of this study was to determine the effect of word meanings on the frequency of dysfluency in Persian-speaking adults with developmental stuttering. Methods: This cross-sectional descriptive-analytic study was performed on 14 adults who stuttered. Their average age was 25 years. The frequency of non-fluency instances was evaluated upon reading two lists containing 60 words and 60 non-words. The words were selected on the basis of common Persian syllable structures. ‘Kolmogoro-Smirnov one sample test’ and paired t-test was used to analyze data the significance level was set at P<0.05. Results:There was a significant difference between the dysfluency in word and non-word lists (P<0.05. Discussion: The findings of this study indicate a significant increase in the frequency of dysfluency on non-words than on real words. It seems that the phonological encodingprocess of non-word reading is much more complex than for word reading, because, in non-word reading, the component of semantic content retrieval (word meaning is missing when compared to word reading.

Continuous exposure to low-frequency noise and carbon disulfide: Combined effects on hearing.

Science.gov (United States)

Venet, Thomas; Carreres-Pons, Maria; Chalansonnet, Monique; Thomas, Aurélie; Merlen, Lise; Nunge, Hervé; Bonfanti, Elodie; Cosnier, Frédéric; Llorens, Jordi; Campo, Pierre

2017-09-01

Carbon disulfide (CS 2 ) is used in industry; it has been shown to have neurotoxic effects, causing central and distal axonopathies.However, it is not considered cochleotoxic as it does not affect hair cells in the organ of Corti, and the only auditory effects reported in the literature were confined to the low-frequency region. No reports on the effects of combined exposure to low-frequency noise and CS 2 have been published to date. This article focuses on the effects on rat hearing of combined exposure to noise with increasing concentrations of CS 2 (0, 63,250, and 500ppm, 6h per day, 5 days per week, for 4 weeks). The noise used was a low-frequency noise ranging from 0.5 to 2kHz at an intensity of 106dB SPL. Auditory function was tested using distortion product oto-acoustic emissions, which mainly reflects the cochlear performances. Exposure to noise alone caused an auditory deficit in a frequency area ranging from 3.6 to 6 kHz. The damaged area was approximately one octave (6kHz) above the highest frequency of the exposure noise (2.8kHz); it was a little wider than expected based on the noise spectrum.Consequently, since maximum hearing sensitivity is located around 8kHz in rats, low-frequency noise exposure can affect the cochlear regions detecting mid-range frequencies. Co-exposure to CS 2 (250-ppm and over) and noise increased the extent of the damaged frequency window since a significant auditory deficit was measured at 9.6kHz in these conditions.Moreover, the significance at 9.6kHz increased with the solvent concentrations. Histological data showed that neither hair cells nor ganglion cells were damaged by CS 2 . This discrepancy between functional and histological data is discussed. Like most aromatic solvents, carbon disulfide should be considered as a key parameter in hearing conservation régulations. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of word frequency and transitional probability on word reading durations of younger and older speakers

NARCIS (Netherlands)

Moers, C.; Meyer, A.S.; Janse, E.

2017-01-01

High-frequency units are usually processed faster than low-frequency units in language comprehension and language production. Frequency effects have been shown for words as well as word combinations. Word co-occurrence effects can be operationalized in terms of transitional probability (TP). TPs

Acoustic and Perceptual Effects of Dysarthria in Greek with a Focus on Lexical Stress

Science.gov (United States)

Papakyritsis, Ioannis

The field of motor speech disorders in Greek is substantially underresearched. Additionally, acoustic studies on lexical stress in dysarthria are generally very rare (Kim et al. 2010). This dissertation examined the acoustic and perceptual effects of Greek dysarthria focusing on lexical stress. Additional possibly deviant speech characteristics were acoustically analyzed. Data from three dysarthric participants and matched controls was analyzed using a case study design. The analysis of lexical stress was based on data drawn from a single word repetition task that included pairs of disyllabic words differentiated by stress location. This data was acoustically analyzed in terms of the use of the acoustic cues for Greek stress. The ability of the dysarthric participants to signal stress in single words was further assessed in a stress identification task carried out by 14 naive Greek listeners. Overall, the acoustic and perceptual data indicated that, although all three dysarthric speakers presented with some difficulty in the patterning of stressed and unstressed syllables, each had different underlying problems that gave rise to quite distinct patterns of deviant speech characteristics. The atypical use of lexical stress cues in Anna's data obscured the prominence relations of stressed and unstressed syllables to the extent that the position of lexical stress was usually not perceptually transparent. Chris and Maria on the other hand, did not have marked difficulties signaling lexical stress location, although listeners were not 100% successful in the stress identification task. For the most part, Chris' atypical phonation patterns and Maria's very slow rate of speech did not interfere with lexical stress signaling. The acoustic analysis of the lexical stress cues was generally in agreement with the participants' performance in the stress identification task. Interestingly, in all three dysarthric participants, but more so in Anna, targets stressed on the 1st

Investigating Strength and Frequency Effects in Recognition Memory Using Type-2 Signal Detection Theory

Science.gov (United States)

Higham, Philip A.; Perfect, Timothy J.; Bruno, Davide

2009-01-01

Criterion- versus distribution-shift accounts of frequency and strength effects in recognition memory were investigated with Type-2 signal detection receiver operating characteristic (ROC) analysis, which provides a measure of metacognitive monitoring. Experiment 1 demonstrated a frequency-based mirror effect, with a higher hit rate and lower…

Ballistic-type field penetration into metals illustrated by high- and low-frequency size-effect measurements in silver

DEFF Research Database (Denmark)

Gantmakher, V. F.; Lebech, Jens; Bak, Christen Kjeldahl

1979-01-01

Radio-frequency size-effect experiments were performed on silver plane-parallel plates at high, 45 GHz, and low, 3 MHz, frequencies. By investigation of size-effect structures we show the influence of frequency on the field distribution inside the metal. When the frequency increases, the splash...

High-frequency intrinsic dynamics of the electrocaloric effect from direct atomistic simulations

Science.gov (United States)

Lisenkov, S.; Ponomareva, I.

2018-05-01

We propose a computational methodology capable of harvesting isothermal heat and entropy change in molecular dynamics simulations. The methodology is applied to study high-frequency dynamics of the electrocaloric effect (ECE) in ferroelectric PbTiO3. ECE is associated with a reversible change in temperature under adiabatic application of electric field or with a reversible change in entropy under isothermal application of the electric field. Accurate assessment of electrocaloric performance requires the knowledge of three quantities: isothermal heat, isothermal entropy change, and adiabatic temperature change. Our methodology allows computations of all these quantities directly, that is, without restoring to the reversible thermodynamical models. Consequently, it captures both reversible and irreversible effects, which is critical for ECE simulations. The approach is well suited to address the dynamics of the ECE, which so far remains underexplored. We report the following basic features of the intrinsic dynamics of ECE: (i) the ECE is independent of the electric field frequency, rate of application, or field profile; (ii) the effect persists up to the frequencies associated with the onset of dielectric losses and deteriorates from there due to the creation of irreversible entropy; and (iii) in the vicinity of the phase transition and in the paraelectric phase the onset of irreversible dynamics occurs at lower frequency as compared to the ferroelectric phase. The latter is attributed to lower intrinsic soft-mode frequencies and and larger losses in the paraelectric phase.

The Ubiquity of Frequency Effects in First Language Acquisition

Science.gov (United States)

Ambridge, Ben; Kidd, Evan; Rowland, Caroline F.; Theakston, Anna L.

2015-01-01

This review article presents evidence for the claim that frequency effects are pervasive in children's first language acquisition, and hence constitute a phenomenon that any successful account must explain. The article is organized around four key domains of research: children's acquisition of single words, inflectional morphology, simple…

Effect of feeding frequency and feeding rate on growth of ...

African Journals Online (AJOL)

Effect of feeding frequency and feeding rate on growth of Oreochromis mossambicus (Teleostei: Cichlidae) fry. ... Weight gain, specific growth rate and gross food conversion ratio were significantly affected by ... AJOL African Journals Online.

An analytical study of the effects of transverse shear deformation and anisotropy on natural vibration frequencies of laminated cylinders

Science.gov (United States)

Jegley, Dawn C.

1988-01-01

Natural vibration frequencies of orthotropic and anisotropic simply supported right circular cylinders are predicted using a higher-order transverse-shear deformation theory. A comparison of natural vibration frequencies predicted by first-order transverse-shear deformation theory and the higher-order theory shows that an additional allowance for transverse shear deformation has a negligible effect on the lowest predicted natural vibration frequencies of laminated cylinders but significantly reduces the higher natural vibration frequencies. A parametric study of the effects of ply orientation on the natural vibration frequencies of laminated cylinders indicates that while stacking sequence affects natural vibration frequencies, cylinder geometry is more important in predicting transverse-shear deformation effects. Interaction curves for cylinders subjected to axial compressive loadings and low natural vibration frequencies indicate that transverse shearing effects are less important in predicting low natural vibration frequencies than in predicting axial compressive buckling loads. The effects of anisotropy are more important than the effects of transverse shear deformation for most strongly anisotropic laminated cylinders in predicting natural vibration frequencies. However, transverse-shear deformation effects are important in predicting high natural vibration frequencies of thick-walled laminated cylinders. Neglecting either anisotropic effects or transverse-shear deformation effects leads to non-conservative errors in predicted natural vibration frequencies.

An analytical study of the effects of transverse shear deformation and anisotropy on natural vibation frequencies of laminated cylinders

Science.gov (United States)

Jegley, Dawn C.

1989-01-01

Natural vibration frequencies of orthotropic and anisotropic simply supported right circular cylinders are predicted using a higher-order transverse-shear deformation theory. A comparison of natural vibration frequencies predicted by first-order transverse-shear deformation theory and the higher-order theory shows that an additional allowance for transverse shear deformation has a negligible effect on the lowest predicted natural vibration frequencies of laminated cylinders but significantly reduces the higher natural vibration frequencies. A parametric study of the effects of ply orientation on the natural vibration frequencies of laminated cylinders indicates that while stacking sequence affects natural vibration frequencies, cylinder geometry is more important in predicting transverse-shear deformation effects. Interaction curves for cylinders subjected to axial compressive loadings and low natural vibration frequencies indicate that transverse shearing effects are less important in predicting low natural vibration frequencies than in predicting axial compressive buckling loads. The effects of anisotropy are more important than the effects of transverse shear deformation for most strongly anisotropic laminated cylinders in predicting natural vibration frequencies. However, transverse-shear deformation effects are important in predicting high natural vibration frequencies of thick-walled laminated cylinders. Neglecting either anisotropic effects or transverse-shear deformation effects leads to non-conservative errors in predicted natural vibration frequencies.

Effects of low-frequency repetitive transcranial magnetic stimulation on event-related potential P300

Science.gov (United States)

Torii, Tetsuya; Sato, Aya; Iwahashi, Masakuni; Iramina, Keiji

2012-04-01

The present study analyzed the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity. P300 latency of event-related potential (ERP) was used to evaluate the effects of low-frequency and short-term rTMS by stimulating the supramarginal gyrus (SMG), which is considered to be the related area of P300 origin. In addition, the prolonged stimulation effects on P300 latency were analyzed after applying rTMS. A figure-eight coil was used to stimulate left-right SMG, and intensity of magnetic stimulation was 80% of motor threshold. A total of 100 magnetic pulses were applied for rTMS. The effects of stimulus frequency at 0.5 or 1 Hz were determined. Following rTMS, an odd-ball task was performed and P300 latency of ERP was measured. The odd-ball task was performed at 5, 10, and 15 min post-rTMS. ERP was measured prior to magnetic stimulation as a control. Electroencephalograph (EEG) was measured at Fz, Cz, and Pz that were indicated by the international 10-20 electrode system. Results demonstrated that different effects on P300 latency occurred between 0.5-1 Hz rTMS. With 1 Hz low-frequency magnetic stimulation to the left SMG, P300 latency decreased. Compared to the control, the latency time difference was approximately 15 ms at Cz. This decrease continued for approximately 10 min post-rTMS. In contrast, 0.5 Hz rTMS resulted in delayed P300 latency. Compared to the control, the latency time difference was approximately 20 ms at Fz, and this delayed effect continued for approximately 15 min post-rTMS. Results demonstrated that P300 latency varied according to rTMS frequency. Furthermore, the duration of the effect was not similar for stimulus frequency of low-frequency rTMS.

THE RECOGNITION OF SPOKEN MONO-MORPHEMIC COMPOUNDS IN CHINESE

Directory of Open Access Journals (Sweden)

Yu-da Lai

2012-12-01

Full Text Available This paper explores the auditory lexical access of mono-morphemic compounds in Chinese as a way of understanding the role of orthography in the recognition of spoken words. In traditional Chinese linguistics, a compound is a word written with two or more characters whether or not they are morphemic. A monomorphemic compound may either be a binding word, written with characters that only appear in this one word, or a non-binding word, written with characters that are chosen for their pronunciation but that also appear in other words. Our goal was to determine if this purely orthographic difference affects auditory lexical access by conducting a series of four experiments with materials matched by whole-word frequency, syllable frequency, cross-syllable predictability, cohort size, and acoustic duration, but differing in binding. An auditory lexical decision task (LDT found an orthographic effect: binding words were recognized more quickly than non-binding words. However, this effect disappeared in an auditory repetition and in a visual LDT with the same materials, implying that the orthographic effect during auditory lexical access was localized to the decision component and involved the influence of cross-character predictability without the activation of orthographic representations. This claim was further confirmed by overall faster recognition of spoken binding words in a cross-modal LDT with different types of visual interference. The theoretical and practical consequences of these findings are discussed.

Reliability and Magnitude of Laterality Effects in Dichotic Listening with Exogenous Cueing

Science.gov (United States)

Voyer, Daniel

2004-01-01

The purpose of the present study was to replicate and extend to word recognition previous findings of reduced magnitude and reliability of laterality effects when exogenous cueing was used in a dichotic listening task with syllable pairs. Twenty right-handed undergraduate students with normal hearing (10 females, 10 males) completed a dichotic…

Effects of Length, Complexity, and Grammatical Correctness on Stuttering in Spanish-Speaking Preschool Children

Science.gov (United States)

Watson, Jennifer B.; Byrd, Courtney T.; Carlo, Edna J.

2011-01-01

Purpose: To explore the effects of utterance length, syntactic complexity, and grammatical correctness on stuttering in the spontaneous speech of young, monolingual Spanish-speaking children. Method: Spontaneous speech samples of 11 monolingual Spanish-speaking children who stuttered, ages 35 to 70 months, were examined. Mean number of syllables,…

Effect of Resistance Training Frequency on Gains in Muscular Strength: A Systematic Review and Meta-Analysis.

Science.gov (United States)

Grgic, Jozo; Schoenfeld, Brad J; Davies, Timothy B; Lazinica, Bruno; Krieger, James W; Pedisic, Zeljko

2018-05-01

Current recommendations on resistance training (RT) frequency for gains in muscular strength are based on extrapolations from limited evidence on the topic, and thus their practical applicability remains questionable. To elucidate this issue, we conducted a systematic review and meta-analysis of the studies that compared muscular strength outcomes with different RT frequencies. To carry out this review, English-language literature searches of the PubMed/MEDLINE, Scopus, and SPORTDiscus databases were conducted. The meta-analysis was performed using a random-effects model. The meta-analysis models were generated with RT frequencies classified as a categorical variable as either 1, 2, 3, or 4+ times/week, or, if there were insufficient data in subgroup analyses, the training frequencies were categorized as 1, 2, or 3 times/week. Subgroup analyses were performed for potential moderators, including (1) training volume; (2) exercise selection for the 1 repetition maximum (RM) test (for both multi-joint and single-joint exercises); (3) upper and lower body strength gains; (4) training to muscular failure (for studies involving and not involving training to muscular failure); (5) age (for both middle-aged/older adults and young adults); and (6) sex (for men and for women). The methodological quality of studies was appraised using the modified Downs and Black checklist. A total of 22 studies were found to meet the inclusion criteria. The average score on the Downs and Black checklist was 18 (range 13-22 points). Four studies were classified as being of good methodological quality, while the rest were classified as being of moderate methodological quality. Results of the meta-analysis showed a significant effect (p = 0.003) of RT frequency on muscular strength gains. Effect sizes increased in magnitude from 0.74, 0.82, 0.93, and 1.08 for training 1, 2, 3, and 4+ times per week, respectively. A subgroup analysis of volume-equated studies showed no significant effect (p

Nonlinear vibration behaviors of suspended cables under two-frequency excitation with temperature effects

Science.gov (United States)

Zhao, Yaobing; Huang, Chaohui; Chen, Lincong; Peng, Jian

2018-03-01

The aim of this paper is to investigate temperature effects on the nonlinear vibration behaviors of suspended cables under two-frequency excitation. For this purpose, two combination and simultaneous resonances are chosen and studied in detail. First of all, based on the assumptions of the temperature effects, the partial differential equations of the in-plane and out-of-plane motions with thermal effects under multi-frequency excitations are obtained. The Galerkin method is adopted to discretize the nonlinear dynamic equations, and the single-mode planar discretization is considered. Then, in the absence of the primary and internal resonances, the frequency response equations are obtained by using the multiple scales method. The stability analyses are conducted via investigating the nature of the singular points of equations. After that, temperature effects on nonlinear vibration characteristics of the first symmetric mode are studied. Parametric investigations of temperature effects on corresponding non-dimensional factors and coefficients of linear and nonlinear terms are performed. Numerical results are presented to show the temperature effects via the frequency-response curves and detuning-phase curves of four different sag-to-span ratios. It is found out that effects of temperature variations would lead to significant quantitative and/or qualitative changes of the nonlinear vibration properties, and these effects are closely related to the sag-to-span ratio and the degree of the temperature variation. Specifically, the softening/hardening-type spring behaviors, the response amplitude, the range of the resonance, the intersection and number of branches, the number and phase of the steady-state solutions are all affected by the temperature changes.

The effects of feeding frequency on waiting time, milking frequency, cubicle and feeding fence utilization for cows in an automatic milking system

NARCIS (Netherlands)

Oostra, H.H.; Stefanowska, J.; Sallvik, K.

2005-01-01

In this trial, the effects of the forage feeding frequency on the waiting time prior to milking and the cowshed facility utilization by cows milked in an automatic milking unit (AMU) were studied. The feeding frequency was increased from two times per day to six times per day. It was found that the

A population memetics approach to cultural evolution in chaffinch song: meme diversity within populations.

Science.gov (United States)

Lynch, A; Baker, A J

1993-04-01

We investigated cultural evolution in populations of common chaffinches (Fringilla coelebs) in the Atlantic islands (Azores, Madeira, Canaries) and neighboring continental regions (Morocco, Iberia) by employing a population memetics approach. To quantify variability within populations, we used the concept of a song meme, defined as a single syllable or a series of linked syllables capable of being transmitted. The frequency distribution of memes within populations generally fit a neutral model in which there is an equilibrium between mutation, migration, and drift, which suggests that memes are functionally equivalent. The diversity of memes of single syllables is significantly greater in the Azores compared to all other regions, consistent with higher population densities of chaffinches there. On the other hand, memes of two to five syllables have greater diversity in Atlantic island and Moroccan populations compared to their Iberian counterparts. This higher diversity emanates from a looser syntax and increased recombination in songs, presumably because of relaxed selection for distinctive songs in these peripheral and depauperate avifaunas. We urge comparative population memetic studies of other species of songbirds and predict that they will lead to a formulation of a general theory for the cultural evolution of bird song analogous to population genetics theory for biological traits.

Using strong nonlinearity and high-frequency vibrations to control effective mechanical stiffness

DEFF Research Database (Denmark)

Thomsen, Jon Juel

2008-01-01

the method of direct separation of motions with results of a modified multiple scales ap-proach, valid also for strong nonlinearity, the stiffening ef-fect is predicted for a generic 1-dof system, and results are tested against numerical simulation and ((it is planned)) laboratory experiments.......High-frequency excitation (HFE) can be used to change the effective stiffness of an elastic structure, and related quanti-ties such as resonance frequencies, wave speed, buckling loads, and equilibrium states. There are basically two ways to do this: By using parametrical HFE (with or without non...

Investigating strength and frequency effects in recognition memory using type-2 signal detection theory.

Science.gov (United States)

Higham, Philip A; Perfect, Timothy J; Bruno, Davide

2009-01-01

Criterion- versus distribution-shift accounts of frequency and strength effects in recognition memory were investigated with Type-2 signal detection receiver operating characteristic (ROC) analysis, which provides a measure of metacognitive monitoring. Experiment 1 demonstrated a frequency-based mirror effect, with a higher hit rate and lower false alarm rate, for low frequency words compared with high frequency words. In Experiment 2, the authors manipulated item strength with repetition, which showed an increased hit rate but no effect on the false alarm rate. Whereas Type-1 indices were ambiguous as to whether these effects were based on a criterion- or distribution-shift model, the two models predict opposite effects on Type-2 distractor monitoring under some assumptions. Hence, Type-2 ROC analysis discriminated between potential models of recognition that could not be discriminated using Type-1 indices alone. In Experiment 3, the authors manipulated Type-1 response bias by varying the number of old versus new response categories to confirm the assumptions made in Experiments 1 and 2. The authors conclude that Type-2 analyses are a useful tool for investigating recognition memory when used in conjunction with more traditional Type-1 analyses.

Demodulation effect is observed in neurones by exposure to low frequency modulated microwaves

International Nuclear Information System (INIS)

Perez-Bruzon, R N; Figols, T; Azanza, M J; Moral, A del

2010-01-01

Neurones exposure to a microwave (carrier f c =13.6 GHz; power P ≅ 5 mW; H o ≅ 0.10 Am -1 = 1.25 mOe; E 0 ≅ 3.5 V/m; ΔT ≅ 0.01 0 C; SAR: 3.1x10 -3 - 5.8x10 -3 W/Kg) EMF amplitude modulated by ELF-AC field (frequency, f m = 0-100 Hz) shows no electrophysiological effect under the carrier MF alone, but f requency resonances: at 2, 4, 8, 12, 16, 50, 100 Hz: demodulation effect. Resonances appear when applied ELF-MF is close to a dominant characteristic frequency of the neurone impulse Fourier spectrum. This is an interesting result considering that ELF-MF modulating RF or MW in the range of human EEG could induce frequency-resonant effects on exposed human brain.

Early use of orthographic information in spoken word recognition: Event-related potential evidence from the Korean language.

Science.gov (United States)

Kwon, Youan; Choi, Sungmook; Lee, Yoonhyoung

2016-04-01

This study examines whether orthographic information is used during prelexical processes in spoken word recognition by investigating ERPs during spoken word processing for Korean words. Differential effects due to orthographic syllable neighborhood size and sound-to-spelling consistency on P200 and N320 were evaluated by recording ERPs from 42 participants during a lexical decision task. The results indicate that P200 was smaller for words whose orthographic syllable neighbors are large in number rather than those that are small. In addition, a word with a large orthographic syllable neighborhood elicited a smaller N320 effect than a word with a small orthographic syllable neighborhood only when the word had inconsistent sound-to-spelling mapping. The results provide support for the assumption that orthographic information is used early during the prelexical spoken word recognition process. © 2015 Society for Psychophysiological Research.

The component structure of ERP subsequent memory effects in the Von Restorff paradigm and the word frequency effect in recall.

Science.gov (United States)

Kamp, Siri-Maria; Brumback, Ty; Donchin, Emanuel

2013-11-01

We examined the degree to which ERP components elicited by items that are isolated from their context, either by their font size ("size isolates") or by their frequency of usage, are correlated with subsequent immediate recall. Study lists contained (a) 15 words including a size isolate, (b) 14 high frequency (HF) words with one low frequency word ("LF isolate"), or (c) 14 LF words with one HF word. We used spatiotemporal PCA to quantify ERP components. We replicated previously reported P300 subsequent memory effects for size isolates and found additional correlations with recall in the novelty P3, a right lateralized positivity, and a left lateralized slow wave that was distinct from the slow wave correlated with recall for nonisolates. LF isolates also showed evidence of a P300 subsequent memory effect and also elicited the left lateralized subsequent memory effect, supporting a role of distinctiveness in word frequency effects in recall. Copyright © 2013 Society for Psychophysiological Research.

Effects of Word Frequency and Transitional Probability on Word Reading Durations of Younger and Older Speakers.

Science.gov (United States)

Moers, Cornelia; Meyer, Antje; Janse, Esther

2017-06-01

High-frequency units are usually processed faster than low-frequency units in language comprehension and language production. Frequency effects have been shown for words as well as word combinations. Word co-occurrence effects can be operationalized in terms of transitional probability (TP). TPs reflect how probable a word is, conditioned by its right or left neighbouring word. This corpus study investigates whether three different age groups-younger children (8-12 years), adolescents (12-18 years) and older (62-95 years) Dutch speakers-show frequency and TP context effects on spoken word durations in reading aloud, and whether age groups differ in the size of these effects. Results show consistent effects of TP on word durations for all age groups. Thus, TP seems to influence the processing of words in context, beyond the well-established effect of word frequency, across the entire age range. However, the study also indicates that age groups differ in the size of TP effects, with older adults having smaller TP effects than adolescent readers. Our results show that probabilistic reduction effects in reading aloud may at least partly stem from contextual facilitation that leads to faster reading times in skilled readers, as well as in young language learners.

Effects of Medical Marijuana on Migraine Headache Frequency in an Adult Population.

Science.gov (United States)

Rhyne, Danielle N; Anderson, Sarah L; Gedde, Margaret; Borgelt, Laura M

2016-05-01

No clinical trials are currently available that demonstrate the effects of marijuana on patients with migraine headache; however, the potential effects of cannabinoids on serotonin in the central nervous system indicate that marijuana may be a therapeutic alternative. Thus, the objective of this study was to describe the effects of medical marijuana on the monthly frequency of migraine headache. Retrospective chart review. Two medical marijuana specialty clinics in Colorado. One hundred twenty-one adults with the primary diagnosis of migraine headache who were recommended migraine treatment or prophylaxis with medical marijuana by a physician, between January 2010 and September 2014, and had at least one follow-up visit. The primary outcome was number of migraine headaches per month with medical marijuana use. Secondary outcomes were the type and dose of medical marijuana used, previous and adjunctive migraine therapies, and patient-reported effects. Migraine headache frequency decreased from 10.4 to 4.6 headaches per month (pmedical marijuana. Most patients used more than one form of marijuana and used it daily for prevention of migraine headache. Positive effects were reported in 48 patients (39.7%), with the most common effects reported being prevention of migraine headache with decreased frequency of migraine headache (24 patients [19.8%]) and aborted migraine headache (14 patients [11.6%]). Inhaled forms of marijuana were commonly used for acute migraine treatment and were reported to abort migraine headache. Negative effects were reported in 14 patients (11.6%); the most common effects were somnolence (2 patients [1.7%]) and difficulty controlling the effects of marijuana related to timing and intensity of the dose (2 patients [1.7%]), which were experienced only in patients using edible marijuana. Edible marijuana was also reported to cause more negative effects compared with other forms. The frequency of migraine headache was decreased with medical

Effect of efferent activation on binaural frequency selectivity.

Science.gov (United States)

Verhey, Jesko L; Kordus, Monika; Drga, Vit; Yasin, Ifat

2017-07-01

Binaural notched-noise experiments indicate a reduced frequency selectivity of the binaural system compared to monaural processing. The present study investigates how auditory efferent activation (via the medial olivocochlear system) affects binaural frequency selectivity in normal-hearing listeners. Thresholds were measured for a 1-kHz signal embedded in a diotic notched-noise masker for various notch widths. The signal was either presented in phase (diotic) or in antiphase (dichotic), gated with the noise. Stimulus duration was 25 ms, in order to avoid efferent activation due to the masker or the signal. A bandpass-filtered noise precursor was presented prior to the masker and signal stimuli to activate the efferent system. The silent interval between the precursor and the masker-signal complex was 50 ms. For comparison, thresholds for detectability of the masked signal were also measured in a baseline condition without the precursor and, in addition, without the masker. On average, the results of the baseline condition indicate an effectively wider binaural filter, as expected. For both signal phases, the addition of the precursor results in effectively wider filters, which is in agreement with the hypothesis that cochlear gain is reduced due to the presence of the precursor. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of meal frequency on postprandial thermogenesis in obese children.

Science.gov (United States)

Molnár, D

1992-01-01

The effect of meal frequency on the thermic effect of food (TEF) was studied in six obese boys and five obese girls (age: mean +/- SE, 12.7 +/- 0.6 yr). Post-absorptive and postprandial resting energy expenditure (REE) were monitored continuously by indirect calorimetry. The children consumed one large liquid meal (LM) or three consecutive small meals (SM) at 1.5 h intervals on subsequent days. The first mode of nutrient intake was determined random. The energy content of the LM and one SM was tailored to provide 30% and 10% of the 24 h postabsorptive REE, respectively. The postprandial changes in REE were monitored for 6 h. The postabsorptive REE (mean +/- SE) was 4.86 +/- 0.28 and 4.9 +/- 0.27 kJ/min before the LM and SM, respectively. REE, respiratory quotient, plasma glucose and insulin concentrations increased sooner, steeper and higher with the LM than with the SM. The magnitude of the TEF was greater (p frequency of food consumption influences the immediate thermogenic response as well as the changes in respiratory quotient, glycaemia and insulinaemia. However, the complex effect of different meal frequencies on the overall energy balance of obese patients cannot be answered on the basis of the present results.

Effective conductivity and permittivity of unsaturated porous materials in the frequency range 1 mHz–1GHz

Science.gov (United States)

Revil, A

2013-01-01

A model combining low-frequency complex conductivity and high-frequency permittivity is developed in the frequency range from 1 mHz to 1 GHz. The low-frequency conductivity depends on pore water and surface conductivities. Surface conductivity is controlled by the electrical diffuse layer, the outer component of the electrical double layer coating the surface of the minerals. The frequency dependence of the effective quadrature conductivity shows three domains. Below a critical frequency fp, which depends on the dynamic pore throat size Λ, the quadrature conductivity is frequency dependent. Between fp and a second critical frequency fd, the quadrature conductivity is generally well described by a plateau when clay minerals are present in the material. Clay-free porous materials with a narrow grain size distribution are described by a Cole-Cole model. The characteristic frequency fd controls the transition between double layer polarization and the effect of the high-frequency permittivity of the material. The Maxwell-Wagner polarization is found to be relatively negligible. For a broad range of frequencies below 1 MHz, the effective permittivity exhibits a strong dependence with the cation exchange capacity and the specific surface area. At high frequency, above the critical frequency fd, the effective permittivity reaches a high-frequency asymptotic limit that is controlled by the two Archie's exponents m and n like the low-frequency electrical conductivity. The unified model is compared with various data sets from the literature and is able to explain fairly well a broad number of observations with a very small number of textural and electrochemical parameters. It could be therefore used to interpret induced polarization, induction-based electromagnetic methods, and ground penetrating radar data to characterize the vadose zone. PMID:23576823

Effect of randomness on multi-frequency aeroelastic responses resolved by Unsteady Adaptive Stochastic Finite Elements

International Nuclear Information System (INIS)

Witteveen, Jeroen A.S.; Bijl, Hester

2009-01-01

The Unsteady Adaptive Stochastic Finite Elements (UASFE) method resolves the effect of randomness in numerical simulations of single-mode aeroelastic responses with a constant accuracy in time for a constant number of samples. In this paper, the UASFE framework is extended to multi-frequency responses and continuous structures by employing a wavelet decomposition pre-processing step to decompose the sampled multi-frequency signals into single-frequency components. The effect of the randomness on the multi-frequency response is then obtained by summing the results of the UASFE interpolation at constant phase for the different frequency components. Results for multi-frequency responses and continuous structures show a three orders of magnitude reduction of computational costs compared to crude Monte Carlo simulations in a harmonically forced oscillator, a flutter panel problem, and the three-dimensional transonic AGARD 445.6 wing aeroelastic benchmark subject to random fields and random parameters with various probability distributions.

Syringeal specialization of frequency control during song production in the Bengalese finch (Lonchura striata domestica.

Directory of Open Access Journals (Sweden)

Kristen R Secora

Full Text Available Singing in songbirds is a complex, learned behavior which shares many parallels with human speech. The avian vocal organ (syrinx has two potential sound sources, and each sound generator is under unilateral, ipsilateral neural control. Different songbird species vary in their use of bilateral or unilateral phonation (lateralized sound production and rapid switching between left and right sound generation (interhemispheric switching of motor control. Bengalese finches (Lonchura striata domestica have received considerable attention, because they rapidly modify their song in response to manipulations of auditory feedback. However, how the left and right sides of the syrinx contribute to acoustic control of song has not been studied.Three manipulations of lateralized syringeal control of sound production were conducted. First, unilateral syringeal muscular control was eliminated by resection of the left or right tracheosyringeal portion of the hypoglossal nerve, which provides neuromuscular innervation of the syrinx. Spectral and temporal features of song were compared before and after lateralized nerve injury. In a second experiment, either the left or right sound source was devoiced to confirm the role of each sound generator in the control of acoustic phonology. Third, air pressure was recorded before and after unilateral denervation to enable quantification of acoustic change within individual syllables following lateralized nerve resection.These experiments demonstrate that the left sound source produces louder, higher frequency, lower entropy sounds, and the right sound generator produces lower amplitude, lower frequency, higher entropy sounds. The bilateral division of labor is complex and the frequency specialization is the opposite pattern observed in most songbirds. Further, there is evidence for rapid interhemispheric switching during song production. Lateralized control of song production in Bengalese finches may enhance acoustic

Are Chinese Correlative Conjunctions Psychologically Real? An Investigation of the Combination Frequency Effect.

Science.gov (United States)

Kong, Lingyue; Zhang, John X; Zhang, Yongwei

2016-08-01

The present study used an online grammaticality judgment task to examine whether Chinese discontinuous correlative conjunctions are psychologically real in mental lexicon. High- and low-frequency discontinuous correlative conjunctions were compared with random combinations differing in combination frequencies but matched for constituent word frequency. Forty graduate students participated in the study. Results showed that responses were faster and more accurate for high-frequency correlative conjunctions than low-frequency ones, but the effects were absent for random combinations. The results indicate that Chinese discontinuous correlative conjunctions have psychological reality in mental lexicon in addition to the representation of their constituent words, and that grammatical functions of correlative conjunctions may be a critical factor for the formation of such holistic representations. © The Author(s) 2016.

Effects of age, task, and frequency on variability of finger tapping.

Science.gov (United States)

Sommervoll, Yngve; Ettema, Gertjan; Vereijken, Beatrix

2011-10-01

The goal was to assess whether prior studies might have overestimated performance variability in older adults in dual task conditions by relying on primary motor tasks that are not constant with aging. 30 younger and 31 older adults performed a bimanual tapping task at four different frequencies in isolation or concurrently with a secondary task. Results showed that performance of younger and older adults was not significantly different in performing the tapping task at all frequencies and with either secondary task, as indicated by mean tapping performance and low number of errors in the secondary tasks. Both groups showed increased variability as tapping frequency increased and with the presence of a secondary task. Tapping concurrently while reading words increased tapping variability more than tapping concurrently while naming colours. Although older participants' performances were overall more variable, no interaction effects with age were found and at the highest frequencies of tapping, younger and older participants did not differ in performance.

Effects of Acute Sacral Neuromodulation at Different Frequencies on Bladder Overactivity in Pigs

Directory of Open Access Journals (Sweden)

Xing Li

2017-06-01

Full Text Available Purpose We investigated the effects of different stimulation frequencies on the inhibition of bladder overactivity by sacral neuromodulation (SNM in pigs. Methods Implant-driven stimulators were used to stimulate the S3 spinal nerve in 13 pigs. Cystometry was performed by infusing normal saline (NS or acetic acid (AA. SNM (pulse width, 210 µsec at frequencies ranging from 5 to 50 Hz was conducted at the intensity threshold at which observable perianal and/or tail movement was induced. Multiple cystometrograms were performed to determine the effects of different frequencies on the micturition reflex. Results AA-induced bladder overactivity significantly reduced the bladder capacity (BC to 34.4%±4.7% of the NS control level (354.4±35.9 mL (P0.05, but SNM at 15, 30, and 50 Hz significantly increased the BC to 54.5%±7.1%, 55.2%±6.5%, and 57.2%±6.1% of the NS control level (P0.05. Conclusions This study demonstrated that 15 Hz was an appropriate frequency for SNM and that frequencies higher than 15 Hz did not lead to better surgical outcomes.

Health effects of low frequency electric and magnetic fields

International Nuclear Information System (INIS)

1992-06-01

The US Department of Labor and the President's Office of Science and Technology Policy (STP) requested that the Committee on interagency Radiation Research and Policy Coordination (CIRRPC) conduct an independent evaluation of the reported health effects from exposure to low-frequency electric and magnetic fields (ELF-EMF), especially reports of carcinogenesis and reproductive and neurophysiological effects focusing on frequencies which appeared to be of greatest public concern. Oak Ridge Associated Universities (ORAU) was tasked by the CIRRPC to oversee the review by a panel of independent, non-Federal, scientists. Following their review of over 1000 journal articles, the ORAU Panel concluded ''... that there is no convincing evidence ... to support the contention that exposure to ELF-EMF generated by sources such as household appliances, video display terminals (10 to 30 KHz), and local power lines (15 to 180 Hz) are demonstrable health hazards.'' Although the Panel noted that some biological effects produced by these fields may be of scientific interest and warrant consideration for future research, it concluded that ''... in the broad scope of research needs in basic science and health research, any health concerns over exposures to these fields should not receive a high priority.'' This executive summary outlines the panel's investigation

[Stimuli phrases of adductor spasmodic dysphonia phonatory break in mandarin Chinese].

Science.gov (United States)

Ge, Pingjiang; Ren, Qingyi; Chen, Zhipeng; Cheng, Qiuhui; Sheng, Xiaoli; Wang, Ling; Chen, Shaohua; Zhang, Siyi

2015-12-01

To investigate the characteristics of adductor spasmodic dysphonia phonatory break in mandarin Chinese and select the stimuli phrases. Thirty-eight patients with adductor spasmodic dysphonia were involved in this study. Standard phrase " fù mŭ xīn" and a speech corpus in mandarin Chinese with 229 syllables covering all vowel and constant of mandarin Chinese were selected. Every patient read the phrases above twice in normal speed and comfortable voice. Two auditory perpetual speech pathologists marked phonatory break syllables respectively. The frequency of phonatory break syllables and their located phrases were calculated, rated and described. The phrases including the most phonatory break syllables were selected as stimuli phrases, the phonatory break frequency of which was also higher than that of standard phrase "fù mŭ xīn". Phonatory break happened in the reading of all patients. The average number of phonatory break syllables was 14 (3-33). Phonatroy break occurred when saying 177 (77.3%) syllables in the speech corpus. The syllables "guŏ, rén, zāng, diàn, chē, gè, guăn, a, bā, ne, de" broke in 23.1%-41.0% patients. These syllables belonged to the phrases "pĭng guŏ, huŏ chē, shì de, nĭ shì gè hăo rén, wŏ mén shì yŏu zŏng shì bă qĭn shì nong dé hĕn zāng, wŏ mén nà biān yŏu wăng qiú yùn dong chăng, cān gŭan, jiŭ bā hé yī gè miàn bāo dìan, tā shì duō me kāng kăi a,wŏ yīng gāi zài xìn lĭ xiĕ yī xiē shén mē ne?". Thirty-seven patients (97.3%) had phonatory break in above mentioned words. Ratios of these words phonatory break also were more than "fù mŭ xīn". Adductor spasmodic dysphonic patients exhibited different degrees of phonatory break in mandarine Chinese. The phrases" shì de, pĭng guŏ, huŏ chē, nĭ shì gè hăo rén, wŏ mén nà biān yŏu wăng qiú yùn dong chăng, cān gŭan, jiŭ bā hé yī gè miàn bāo dìan, tā shì duō me kāng kăi a" were recommended as stimuli

Breathing frequency-independent effect of Tai Chi Chuan on autonomic modulation.

Science.gov (United States)

Lu, Wan-An; Kuo, Cheng-Deng

2014-04-01

This study investigates the breathing frequency (BF)-independent effect of Tai Chi Chuan (TCC) on autonomic nervous modulation in TCC practitioners. Twenty-five TCC practitioners and 25 sedentary normal controls were recruited. The stationary heart rate variability (HRV) measures of TCC practitioners and controls were compared. The same HRV measures in TCC practitioners and among the controls, TCC practitioners before TCC and TCC practitioners 30 min after TCC were compared. In TCC practitioners, the BF, normalized high-frequency power (nHFP), and normalized very low-frequency power were significantly increased, while the normalized low-frequency power (nLFP) was significantly decreased 30 min after TCC. The BF correlated significantly and negatively with heart rate (HR), nHFP and nLFP, and correlated significantly and positively with mean RR interval (MnRR) before TCC in TCC practitioners. A slower BF is associated with a higher HR, a greater vagal modulation, and a greater combined sympatho-vagal modulation before TCC. To remove the effect of BF on HRV measures, new indices such as HR*BF, nHFP*BF, nLFP*BF, and MnRR/BF were introduced for comparison among the controls, TCC practitioners before TCC, and TCC practitioners 30 min after TCC. Thirty minutes after TCC, the MnRR/BF of TCC practitioner was smaller whereas HR*BF and nHFP*BF were greater than those before TCC. The BF-independent effects of TCC on the autonomic nervous modulation of TCC practitioners are an increase in vagal modulation and HR, and a decrease in mean RR interval. The mechanism underlying the parallel increase in HR and vagal modulation in TCC practitioners is not understood yet at present.

Frequency effects on the scale and behavior of acoustic streaming.

Science.gov (United States)

Dentry, Michael B; Yeo, Leslie Y; Friend, James R

2014-01-01

Acoustic streaming underpins an exciting range of fluid manipulation phenomena of rapidly growing significance in microfluidics, where the streaming often assumes the form of a steady, laminar jet emanating from the device surface, driven by the attenuation of acoustic energy within the beam of sound propagating through the liquid. The frequencies used to drive such phenomena are often chosen ad hoc to accommodate fabrication and material issues. In this work, we seek a better understanding of the effects of sound frequency and power on acoustic streaming. We present and, using surface acoustic waves, experimentally verify a laminar jet model that is based on the turbulent jet model of Lighthill, which is appropriate for acoustic streaming seen at micro- to nanoscales, between 20 and 936 MHz and over a broad range of input power. Our model eliminates the critically problematic acoustic source singularity present in Lighthill's model, replacing it with a finite emission area and enabling determination of the streaming velocity close to the source. At high acoustic power P (and hence high jet Reynolds numbers ReJ associated with fast streaming), the laminar jet model predicts a one-half power dependence (U∼P1/2∼ ReJ) similar to the turbulent jet model. However, the laminar model may also be applied to jets produced at low powers-and hence low jet Reynolds numbers ReJ-where a linear relationship between the beam power and streaming velocity exists: U∼P∼ReJ2. The ability of the laminar jet model to predict the acoustic streaming behavior across a broad range of frequencies and power provides a useful tool in the analysis of microfluidics devices, explaining peculiar observations made by several researchers in the literature. In particular, by elucidating the effects of frequency on the scale of acoustically driven flows, we show that the choice of frequency is a vitally important consideration in the design of small-scale devices employing acoustic streaming

The effect of gamma radiation on recombination frequency in Caenorhabditis elegans

International Nuclear Information System (INIS)

Kim, J.S.; Rose, A.M.

1987-01-01

We have studied the effect of gamma radiation on recombination frequency for intervals across the cluster of linkage group I in Caenorhabditis elegans. Recombination frequency increased approximately twofold across the dpy-5-unc-13 interval after treatment with 2000 rads (1 rad = 10 mGy) of cobalt 60 gamma radiation. Several factors affecting the magnitude of the increase have been characterized. Recombination frequency increased more with higher doses of radiation. However, the increase in recombination frequency with increasing dose was accompanied by a reduced average number of progeny from radiation-treated individuals. The amount of the increase was affected by meiotic stage, age at the time of treatment (premeiotic), and radiation dose. The increase in recombination was detectable in the B brood and remained elevated for the remainder of egg production. X-chromosome nondisjunction was also increased by radiation treatment. A high frequency of the recombinant progeny produced with radiation treatment were sterile unlike their nonrecombinant siblings. When parameters affecting recombination frequency are held constant during treatment, chromosomal regions of high gene density on the meiotic map increased more (fourfold) than an adjacent region of low gene density (no increase). The greatest was across the dpy-14-unc-13 interval near the center of the gene cluster. These results may suggest that the physical length of DNA per map unit is greater within the cluster than outside

The Effect of Flow Frequency on Internet Addiction to Different Internet Usage Activities

Science.gov (United States)

Yang, Hui-Ling; Wu, Wei-Pang

2017-01-01

This study investigated the online flow frequency among college students in regard to different internet activities, and analyzed the effect of flow frequency on internet addiction. This study surveyed 525 undergraduate internet users in Taiwan by using convenience sampling to question participants. In this paper, analysis of variance (ANOVA) was…

Effects of extremely low-frequency magnetotherapy on proliferation of human dermal fibroblasts.

Science.gov (United States)

Pasi, Francesca; Sanna, Samuele; Paolini, Alessandro; Alquati, Marco; Lascialfari, Alessandro; Corti, Maurizio Enrico; Liberto, Riccardo Di; Cialdai, Francesca; Monici, Monica; Nano, Rosanna

2016-01-01

Extremely low-frequency electromagnetic fields (ELF-EMFs) applied in magnetotherapy have frequency lower than 100 Hz and magnetic field intensity ranging from 0.1 to 20 mT. For many years, the use of magnetotherapy in clinics has been increasing because of its beneficial effects in many processes, e.g., skin diseases, inflammation and bone disorders. However, the understanding of the microscopic mechanisms governing such processes is still lacking and the results of the studies on the effects of ELF-EMFs are controversial because effects derive from different conditions and from intrinsic responsiveness of different cell types.In the present study, we studied the biological effects of 1.5 h exposure of human dermal fibroblasts to EMFs with frequencies of 5 and 50 Hz and intensity between 0.25 and 1.6 mT. Our data showed that the magnetic treatment did not produce changes in cell viability, but gave evidence of a sizeable decrease in proliferation at 24 h after treatment. In addition, immunofluorescence experiments displayed an increase in tubulin expression that could foreshadow changes in cell motility or morphology. The decrease in proliferation with unchanged viability and increase in tubulin expression could be consistent with the triggering of a transdifferentiation process after the exposure to ELF-EMFs.

Molecular gyroscopes and biological effects of weak extremely low-frequency magnetic fields

International Nuclear Information System (INIS)

Binhi, V.N.; Savin, A.V.

2002-01-01

Extremely low-frequency magnetic fields are known to affect biological systems. In many cases, biological effects display 'windows' in biologically effective parameters of the magnetic fields: most dramatic is the fact that the relatively intense magnetic fields sometimes do not cause appreciable effect, while smaller fields of the order of 10-100 μT do. Linear resonant physical processes do not explain the frequency windows in this case. Amplitude window phenomena suggest a nonlinear physical mechanism. Such a nonlinear mechanism has been proposed recently to explain those 'windows'. It considers the quantum-interference effects on the protein-bound substrate ions. Magnetic fields cause an interference of ion quantum states and change the probability of ion-protein dissociation. This ion-interference mechanism predicts specific magnetic-field frequency and amplitude windows within which the biological effects occur. It agrees with a lot of experiments. However, according to the mechanism, the lifetime Γ -1 of ion quantum states within a protein cavity should be of unrealistic value, more than 0.01 s for frequency band 10-100 Hz. In this paper, a biophysical mechanism has been proposed, which (i) retains the attractive features of the ion interference mechanism, i.e., predicts physical characteristics that might be experimentally examined and (ii) uses the principles of gyroscopic motion and removes the necessity to postulate large lifetimes. The mechanism considers the dynamics of the density matrix of the molecular groups, which are attached to the walls of protein cavities by two covalent bonds, i.e., molecular gyroscopes. Numerical computations have shown almost free rotations of the molecular gyroscopes. The relaxation time due to van der Waals forces was about 0.01 s for the cavity size of 28 Aa

Frequency effects of upstream wake and blade interaction on the unsteady boundary layer flow

International Nuclear Information System (INIS)

Kang, Dong Jin; Bae, Sang Su

2002-01-01

Effects of the reduced frequency of upstream wake on downstream unsteady boundary layer flow were simulated by using a Navier-Stokes code. The Navier-Stokes code is based on an unstructured finite volume method and uses a low Reynolds number turbulence model to close the momentum equations. The geometry used in this paper is the MIT flapping foil experimental set-up and the reduced frequency of the upstream wake is varied in the range of 0.91 to 10.86 to study its effect on the unsteady boundary layer flow. Numerical solutions show that they can be divided into two categories. One is so called the low frequency solution, and behaves quite similar to a Stokes layer. Its characteristics is found to be quite similar to those due to either a temporal or spatial wave. The low frequency solutions are observed clearly when reduced frequency is smaller than 3.26. The other one is the high frequency solution. It is observed for the reduced frequency larger than 7.24. It shows a sudden shift of the phase angle of the unsteady velocity around the edge of the boundary layer. The shift of phase angle is about 180 degree, and leads to separation of the boundary layer flow from corresponding outer flow. The high frequency solution shows the characteristics of a temporal wave whose wave length is half of the upstream frequency. This characteristics of the high frequency solution is found to be caused by the strong interaction between unsteady vortices. This strong interaction also leads to destroy of the upstream wake stripe inside the viscous sublayer as well as the buffer layer

A Causal Inference Model Explains Perception of the McGurk Effect and Other Incongruent Audiovisual Speech.

Directory of Open Access Journals (Sweden)

John F Magnotti

2017-02-01

Full Text Available Audiovisual speech integration combines information from auditory speech (talker's voice and visual speech (talker's mouth movements to improve perceptual accuracy. However, if the auditory and visual speech emanate from different talkers, integration decreases accuracy. Therefore, a key step in audiovisual speech perception is deciding whether auditory and visual speech have the same source, a process known as causal inference. A well-known illusion, the McGurk Effect, consists of incongruent audiovisual syllables, such as auditory "ba" + visual "ga" (AbaVga, that are integrated to produce a fused percept ("da". This illusion raises two fundamental questions: first, given the incongruence between the auditory and visual syllables in the McGurk stimulus, why are they integrated; and second, why does the McGurk effect not occur for other, very similar syllables (e.g., AgaVba. We describe a simplified model of causal inference in multisensory speech perception (CIMS that predicts the perception of arbitrary combinations of auditory and visual speech. We applied this model to behavioral data collected from 60 subjects perceiving both McGurk and non-McGurk incongruent speech stimuli. The CIMS model successfully predicted both the audiovisual integration observed for McGurk stimuli and the lack of integration observed for non-McGurk stimuli. An identical model without causal inference failed to accurately predict perception for either form of incongruent speech. The CIMS model uses causal inference to provide a computational framework for studying how the brain performs one of its most important tasks, integrating auditory and visual speech cues to allow us to communicate with others.

The low-frequency encoding disadvantage: Word frequency affects processing demands.

Science.gov (United States)

Diana, Rachel A; Reder, Lynne M

2006-07-01

Low-frequency words produce more hits and fewer false alarms than high-frequency words in a recognition task. The low-frequency hit rate advantage has sometimes been attributed to processes that operate during the recognition test (e.g., L. M. Reder et al., 2000). When tasks other than recognition, such as recall, cued recall, or associative recognition, are used, the effects seem to contradict a low-frequency advantage in memory. Four experiments are presented to support the claim that in addition to the advantage of low-frequency words at retrieval, there is a low-frequency disadvantage during encoding. That is, low-frequency words require more processing resources to be encoded episodically than high-frequency words. Under encoding conditions in which processing resources are limited, low-frequency words show a larger decrement in recognition than high-frequency words. Also, studying items (pictures and words of varying frequencies) along with low-frequency words reduces performance for those stimuli. Copyright 2006 APA, all rights reserved.

Focal/Nonfocal Cue Effects in Prospective Memory: Monitoring Difficulty or Different Retrieval Processes?

Science.gov (United States)

Scullin, Michael K.; McDaniel, Mark A.; Shelton, Jill T.; Lee, Ji Hae

2010-01-01

We investigated whether focal/nonfocal effects (e.g., Einstein et al., 2005) in prospective memory (PM) are explained by cue differences in monitoring difficulty. In Experiment 1, we show that syllable cues (used in Einstein et al., 2005) are more difficult to monitor for than are word cues; however, initial-letter cues (in words) are similar in…

Spatio-temporal distribution of brain activity associated with audio-visually congruent and incongruent speech and the McGurk Effect.

Science.gov (United States)

Pratt, Hillel; Bleich, Naomi; Mittelman, Nomi

2015-11-01

Spatio-temporal distributions of cortical activity to audio-visual presentations of meaningless vowel-consonant-vowels and the effects of audio-visual congruence/incongruence, with emphasis on the McGurk effect, were studied. The McGurk effect occurs when a clearly audible syllable with one consonant, is presented simultaneously with a visual presentation of a face articulating a syllable with a different consonant and the resulting percept is a syllable with a consonant other than the auditorily presented one. Twenty subjects listened to pairs of audio-visually congruent or incongruent utterances and indicated whether pair members were the same or not. Source current densities of event-related potentials to the first utterance in the pair were estimated and effects of stimulus-response combinations, brain area, hemisphere, and clarity of visual articulation were assessed. Auditory cortex, superior parietal cortex, and middle temporal cortex were the most consistently involved areas across experimental conditions. Early (visual cortex. Clarity of visual articulation impacted activity in secondary visual cortex and Wernicke's area. McGurk perception was associated with decreased activity in primary and secondary auditory cortices and Wernicke's area before 100 msec, increased activity around 100 msec which decreased again around 180 msec. Activity in Broca's area was unaffected by McGurk perception and was only increased to congruent audio-visual stimuli 30-70 msec following consonant onset. The results suggest left hemisphere prominence in the effects of stimulus and response conditions on eight brain areas involved in dynamically distributed parallel processing of audio-visual integration. Initially (30-70 msec) subcortical contributions to auditory cortex, superior parietal cortex, and middle temporal cortex occur. During 100-140 msec, peristriate visual influences and Wernicke's area join in the processing. Resolution of incongruent audio-visual inputs is then

Effects of low-frequency ultrasound on microcirculation in venous leg ulcers

Directory of Open Access Journals (Sweden)

Uwe Wollina

2011-01-01

Full Text Available Background: Therapeutic low-frequency ultrasound (US has been used for many years to improve wound healing in chronic wounds like venous leg ulcers. No human data are available for the possible effects of single US applications on microcirculation and their frequency-dependency. Aims: To investigated the role of therapeutic low-frequency US on microcirculation of venous leg ulcers in vivo. Patients and Methods: This is a pilot study on an inpatient basis. We use a newly developed low-frequency continuous-wave US-equipment composed of a US transducer based on piezo-fiber composites that allow the change of frequency. In this study, we apply US of 34 kHz, 53.5 kHz, and 75 kHz respectively. Twelve patients with chronic venous leg ulcers are analyzed. As an adjunct to good ulcer care, therapeutic US is applied, non-contacting, once a day, in a subaqual position for 10 minutes. Microcirculation is assessed in the ulcers adjacent to skin before US-therapy, immediately after the treatment and 30 minutes later. We use a micro-light guide spectrophotometer (O2C, LEA Medizintechnik GmbH, Gieίen, Germany for calculation of blood flow velocity, hemoglobin oxygen saturation (SCO 2 and relative hemoglobin concentration (rHb in 2 and 8 mm depth. Contact-free remission spectroscopy (SkinREM3, Color Control Chemnitz GmbH, Chemnitz, Germany allows contact free measurements in the VIS-NIR range of the spectrum (400 ± 1600 nm. Results: It is seen that therapeutic US is well tolerated. One patient dropped out from a treatment series since he developed erysipelas responding to standard antibiotic. Effects were seen at 34 kHz only. The SO 2 values increased after single US application. The values for rHb were higher in the superficial layer of the wound bed (depth 2 mm compared to deeper parts (8 mm depth. US treatment did not result in significant changes of rHb and blood cell velocity. The data obtained by remission spectroscopy disclose an increase of oxygenized

Effect of. gamma. -radiation on chiasma frequency in four inbred strains of Trigonella L

Energy Technology Data Exchange (ETDEWEB)

Venkateswara Rao, T; Lakshmi, N

1983-12-01

The effect of ..gamma..-rays on chiasma frequency was studied in M/sub 1/ plants of three inbred strains of T. foenum-graecum and T. corniculata. The response of the varieties to different doses of radiation with respect to chaiasma frequency was found to be different on the basis of students 't' test. In all the treated strains a decrease in chiasma frequency was observed compared to controls and the decrease was found to be inversely proportional to the dose. The possible causes for reduction in chiasma frequency are discussed. 16 refs., 3 tables.

The Phoneme Identification Test for Assessment of Spectral and Temporal Discrimination Skills in Children: Development, Normative Data, and Test-Retest Reliability Studies.

Science.gov (United States)

Cameron, Sharon; Chong-White, Nicky; Mealings, Kiri; Beechey, Tim; Dillon, Harvey; Young, Taegan

2018-02-01

Previous research suggests that a proportion of children experiencing reading and listening difficulties may have an underlying primary deficit in the way that the central auditory nervous system analyses the perceptually important, rapidly varying, formant frequency components of speech. The Phoneme Identification Test (PIT) was developed to investigate the ability of children to use spectro-temporal cues to perceptually categorize speech sounds based on their rapidly changing formant frequencies. The PIT uses an adaptive two-alternative forced-choice procedure whereby the participant identifies a synthesized consonant-vowel (CV) (/ba/ or /da/) syllable. CV syllables differed only in the second formant (F2) frequency along an 11-step continuum (between 0% and 100%-representing an ideal /ba/ and /da/, respectively). The CV syllables were presented in either quiet (PIT Q) or noise at a 0 dB signal-to-noise ratio (PIT N). Development of the PIT stimuli and test protocols, and collection of normative and test-retest reliability data. Twelve adults (aged 23 yr 10 mo to 50 yr 9 mo, mean 32 yr 5 mo) and 137 typically developing, primary-school children (aged 6 yr 0 mo to 12 yr 4 mo, mean 9 yr 3 mo). There were 73 males and 76 females. Data were collected using a touchscreen computer. Psychometric functions were automatically fit to individual data by the PIT software. Performance was determined by the width of the continuum for which responses were neither clearly /ba/ nor /da/ (referred to as the uncertainty region [UR]). A shallower psychometric function slope reflected greater uncertainty. Age effects were determined based on raw scores. Z scores were calculated to account for the effect of age on performance. Outliers, and individual data for which the confidence interval of the UR exceeded a maximum allowable value, were removed. Nonparametric tests were used as the data were skewed toward negative performance. Across participants, the median value of the F2 range

Effect of power frequency excitation character on ferroresonance in neutral-grounded system

International Nuclear Information System (INIS)

Hui Meng; Liu Chong-Xin

2010-01-01

In most earlier ferroresonance studies the traditional excitation characteristic of iron core, in which the traditional excitation characteristic contains harmonic voltages or currents, has been used as if it were made up of pure fundamental voltage or current. However, this is not always true. In comparison with traditional excitation characteristics, this paper introduces the power frequency excitation characteristic of the iron core, which contains no harmonics. The power frequency excitation characteristic of iron core has been obtained by Elector Magnetic Transient Program, resulting in discrete voltage and current pairs. Extensive simulations are carried out to analyse the effect of power frequency excitation characteristic on potential transformer ferroresonance. A detailed analysis of simulation results demonstrates that with power frequency excitation characteristic of iron core inclusion at certain excitation voltage the ferroresonance may happen, conversely it may not happen with traditional excitation characteristic inclusion. (general)

Nonlinear frequency compression: effects on sound quality ratings of speech and music.

Science.gov (United States)

Parsa, Vijay; Scollie, Susan; Glista, Danielle; Seelisch, Andreas

2013-03-01

Frequency lowering technologies offer an alternative amplification solution for severe to profound high frequency hearing losses. While frequency lowering technologies may improve audibility of high frequency sounds, the very nature of this processing can affect the perceived sound quality. This article reports the results from two studies that investigated the impact of a nonlinear frequency compression (NFC) algorithm on perceived sound quality. In the first study, the cutoff frequency and compression ratio parameters of the NFC algorithm were varied, and their effect on the speech quality was measured subjectively with 12 normal hearing adults, 12 normal hearing children, 13 hearing impaired adults, and 9 hearing impaired children. In the second study, 12 normal hearing and 8 hearing impaired adult listeners rated the quality of speech in quiet, speech in noise, and music after processing with a different set of NFC parameters. Results showed that the cutoff frequency parameter had more impact on sound quality ratings than the compression ratio, and that the hearing impaired adults were more tolerant to increased frequency compression than normal hearing adults. No statistically significant differences were found in the sound quality ratings of speech-in-noise and music stimuli processed through various NFC settings by hearing impaired listeners. These findings suggest that there may be an acceptable range of NFC settings for hearing impaired individuals where sound quality is not adversely affected. These results may assist an Audiologist in clinical NFC hearing aid fittings for achieving a balance between high frequency audibility and sound quality.

The Effects of Semantic Transparency and Base Frequency on the Recognition of English Complex Words

Science.gov (United States)

Xu, Joe; Taft, Marcus

2015-01-01

A visual lexical decision task was used to examine the interaction between base frequency (i.e., the cumulative frequencies of morphologically related forms) and semantic transparency for a list of derived words. Linear mixed effects models revealed that high base frequency facilitates the recognition of the complex word (i.e., a "base…

The Effect of Communications Medium on the Fundamental Frequency of Speech.

Science.gov (United States)

Noll, A. Michael

1978-01-01

Describes the results of preliminary experiments to investigate the effects of communications medium (face-to-face and two-way closed circuit television) on the fundamental frequency of speakers in a dyadic communications situation. (JMF)

Spin-dependent tunnelling at infrared frequencies: magnetorefractive effect in magnetic nanocomposites

International Nuclear Information System (INIS)

Granovsky, A.B.; Inoue, Mitsuteru

2004-01-01

We present a brief review of recent experimental and theoretical results on magnetorefractive effect in magnetic metal-insulator nanogranular alloys with tunnel-type magnetoresistance focusing on its relation with high-frequency spin-dependent tunnelling

Spin-dependent tunnelling at infrared frequencies: magnetorefractive effect in magnetic nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Granovsky, A.B. E-mail: granov@magn.ru; Inoue, Mitsuteru

2004-05-01

We present a brief review of recent experimental and theoretical results on magnetorefractive effect in magnetic metal-insulator nanogranular alloys with tunnel-type magnetoresistance focusing on its relation with high-frequency spin-dependent tunnelling.

Theoretical approach for plasma series resonance effect in geometrically symmetric dual radio frequency plasma

International Nuclear Information System (INIS)

Bora, B.; Bhuyan, H.; Favre, M.; Wyndham, E.; Chuaqui, H.

2012-01-01

Plasma series resonance (PSR) effect is well known in geometrically asymmetric capacitively couple radio frequency plasma. However, plasma series resonance effect in geometrically symmetric plasma has not been properly investigated. In this work, a theoretical approach is made to investigate the plasma series resonance effect and its influence on Ohmic and stochastic heating in geometrically symmetric discharge. Electrical asymmetry effect by means of dual frequency voltage waveform is applied to excite the plasma series resonance. The results show considerable variation in heating with phase difference between the voltage waveforms, which may be applicable in controlling the plasma parameters in such plasma.

Effects of dynamic-demand-control appliances on the power grid frequency

Science.gov (United States)

Tchuisseu, E. B. Tchawou; Gomila, D.; Brunner, D.; Colet, P.

2017-08-01

Power grid frequency control is a demanding task requiring expensive idle power plants to adapt the supply to the fluctuating demand. An alternative approach is controlling the demand side in such a way that certain appliances modify their operation to adapt to the power availability. This is especially important to achieve a high penetration of renewable energy sources. A number of methods to manage the demand side have been proposed. In this work we focus on dynamic demand control (DDC), where smart appliances can delay their switchings depending on the frequency of the system. We introduce a simple model to study the effects of DDC on the frequency of the power grid. The model includes the power plant equations, a stochastic model for the demand that reproduces, adjusting a single parameter, the statistical properties of frequency fluctuations measured experimentally, and a generic DDC protocol. We find that DDC can reduce small and medium-size fluctuations but it can also increase the probability of observing large frequency peaks due to the necessity of recovering pending task. We also conclude that a deployment of DDC around 30-40% already allows a significant reduction of the fluctuations while keeping the number of pending tasks low.

Temperature and loading frequency effects of fatigue crack growth in HDPE pipe material

International Nuclear Information System (INIS)

Merah, N.; Khan, Z.; Bazoune, A.; Saghir, F.

2006-01-01

High density polyethylene (HDPE) pipes are being extensively used for gas, water, sewage and waste water distribution systems. Laboratory tests appear to show that HDPE is more able to suppress rapid crack propagation, while remaining somehow resistant to slow crack growth failures observed in service. Procedures for estimating pipe life in service have been established by making use of fatigue crack growth (FCG) results. These procedures are concerned mainly with room temperature. Applications with some safety factor to include the temperature effect. Use of HDPE pipes in water and gas distribution in the Gulf area has seen a net increase. This study addresses the combined effects of temperature and frequency on FCG properties of commercial HDPE pipe material. FCG accelerated tests were conducted on single-etch notch (SEN) specimens in the temperature range of -10 to 70C at frequencies ranging from 0.1 to 50 Hz. The FCG tests are conducted at a stress amplitude level approximately 1/4 of room temperature yield stress and crack growth behavior was investigated using linear elastic fracture mechanics concepts. The stress intensity range delta K gave satisfactory correlation of crack, growth rate (da/dN) at the temperatures of -10, 0, 23 and 40C and at frequencies of 0.1, 1, and 50 Hz. The crack growth resistance was found to decrease with increase in test temperature and decrease growth resistance was found to decrease with increase in test temperature and decrease with frequency. For 70C no crack propagation was observed, the failure was observed to occur by collapse or generalized yielding. Fractographic analyses results are used to explain temperature and frequency effects on FCG. The effect of temperature on da/dN for HDPE material was investigated by considering the variation of mechanical properties with temperature. Master curves were developed by normalizing delta K yield stress. (author)

Stress Recovery Effects of High- and Low-Frequency Amplified Music on Heart Rate Variability.

Science.gov (United States)

Nakajima, Yoshie; Tanaka, Naofumi; Mima, Tatsuya; Izumi, Shin-Ichi

Sounds can induce autonomic responses in listeners. However, the modulatory effect of specific frequency components of music is not fully understood. Here, we examined the role of the frequency component of music on autonomic responses. Specifically, we presented music that had been amplified in the high- or low-frequency domains. Twelve healthy women listened to white noise, a stress-inducing noise, and then one of three versions of a piece of music: original, low-, or high-frequency amplified. To measure autonomic response, we calculated the high-frequency normalized unit (HFnu), low-frequency normalized unit, and the LF/HF ratio from the heart rate using electrocardiography. We defined the stress recovery ratio as the value obtained after participants listened to music following scratching noise, normalized by the value obtained after participants listened to white noise after the stress noise, in terms of the HFnu, low-frequency normalized unit, LF/HF ratio, and heart rate. Results indicated that high-frequency amplified music had the highest HFnu of the three versions. The stress recovery ratio of HFnu under the high-frequency amplified stimulus was significantly larger than that under the low-frequency stimulus. Our results suggest that the high-frequency component of music plays a greater role in stress relief than low-frequency components.

Role of the motor system in language knowledge.

Science.gov (United States)

Berent, Iris; Brem, Anna-Katharine; Zhao, Xu; Seligson, Erica; Pan, Hong; Epstein, Jane; Stern, Emily; Galaburda, Albert M; Pascual-Leone, Alvaro

2015-02-17

All spoken languages express words by sound patterns, and certain patterns (e.g., blog) are systematically preferred to others (e.g., lbog). What principles account for such preferences: does the language system encode abstract rules banning syllables like lbog, or does their dislike reflect the increased motor demands associated with speech production? More generally, we ask whether linguistic knowledge is fully embodied or whether some linguistic principles could potentially be abstract. To address this question, here we gauge the sensitivity of English speakers to the putative universal syllable hierarchy (e.g., blif ≻ bnif ≻ bdif ≻ lbif) while undergoing transcranial magnetic stimulation (TMS) over the cortical motor representation of the left orbicularis oris muscle. If syllable preferences reflect motor simulation, then worse-formed syllables (e.g., lbif) should (i) elicit more errors; (ii) engage more strongly motor brain areas; and (iii) elicit stronger effects of TMS on these motor regions. In line with the motor account, we found that repetitive TMS pulses impaired participants' global sensitivity to the number of syllables, and functional MRI confirmed that the cortical stimulation site was sensitive to the syllable hierarchy. Contrary to the motor account, however, ill-formed syllables were least likely to engage the lip sensorimotor area and they were least impaired by TMS. Results suggest that speech perception automatically triggers motor action, but this effect is not causally linked to the computation of linguistic structure. We conclude that the language and motor systems are intimately linked, yet distinct. Language is designed to optimize motor action, but its knowledge includes principles that are disembodied and potentially abstract.

Role of the motor system in language knowledge

Science.gov (United States)

Berent, Iris; Brem, Anna-Katharine; Zhao, Xu; Seligson, Erica; Pan, Hong; Epstein, Jane; Stern, Emily; Galaburda, Albert M.; Pascual-Leone, Alvaro

2015-01-01

All spoken languages express words by sound patterns, and certain patterns (e.g., blog) are systematically preferred to others (e.g., lbog). What principles account for such preferences: does the language system encode abstract rules banning syllables like lbog, or does their dislike reflect the increased motor demands associated with speech production? More generally, we ask whether linguistic knowledge is fully embodied or whether some linguistic principles could potentially be abstract. To address this question, here we gauge the sensitivity of English speakers to the putative universal syllable hierarchy (e.g., blif≻bnif≻bdif≻lbif) while undergoing transcranial magnetic stimulation (TMS) over the cortical motor representation of the left orbicularis oris muscle. If syllable preferences reflect motor simulation, then worse-formed syllables (e.g., lbif) should (i) elicit more errors; (ii) engage more strongly motor brain areas; and (iii) elicit stronger effects of TMS on these motor regions. In line with the motor account, we found that repetitive TMS pulses impaired participants’ global sensitivity to the number of syllables, and functional MRI confirmed that the cortical stimulation site was sensitive to the syllable hierarchy. Contrary to the motor account, however, ill-formed syllables were least likely to engage the lip sensorimotor area and they were least impaired by TMS. Results suggest that speech perception automatically triggers motor action, but this effect is not causally linked to the computation of linguistic structure. We conclude that the language and motor systems are intimately linked, yet distinct. Language is designed to optimize motor action, but its knowledge includes principles that are disembodied and potentially abstract. PMID:25646465

Frequency Dependence of Helioseismic Measurements of the Center-to-Limb Effect and Flow-induced Travel-time Shifts

Science.gov (United States)

Chen, Ruizhu; Zhao, Junwei

2018-02-01

Time–distance helioseismology measures acoustic travel times to infer the structure and flow field of the solar interior; however, both the mean travel times and the travel-time shifts suffer systematic center-to-limb variations, which complicate the interpretation and inversions of the time–distance measurements. In particular, the center-to-limb variation in travel-time shifts (CtoL effect) has a significant impact on the inference of the Sun’s meridional circulation, and needs to be removed from the helioseismic measurements, although the observational properties and the physical cause of the CtoL effect have yet to be investigated. In this study, we measure the CtoL effect in the frequency domain using Doppler-velocity data from the Solar Dynamics Observatory/Helioseismic and Magnetic Imager, and study its properties as a function of disk-centric distance, travel distance, and frequency of acoustic waves. It is found that the CtoL effect has a significant frequency dependence—it reverses sign at a frequency around 5.4 mHz and reaches maximum at around 4.0 mHz before the sign reversal. The tendency of frequency dependence varies with disk-centric distance in a way that both the sign-reversal frequency and the maximum-value frequency decrease closer to the limb. The variation tendency does not change with travel distance, but the variation magnitude is approximately proportional to travel distance. For comparison, the flow-induced travel-time shifts show little frequency dependence. These observational properties provide more clues on the nature of the CtoL effect, and also possibly lead to new ways of effect-removal for a more robust determination of the deep meridional flow.

Effects of weak nonlinearity on dispersion relations and frequency band-gaps of periodic structures

DEFF Research Database (Denmark)

Sorokin, Vladislav; Thomsen, Jon Juel

2015-01-01

of these for nonlinear problems is impossible or cumbersome, since Floquet theory is applicable for linear systems only. Thus the nonlinear effects for periodic structures are not yet fully uncovered, while at the same time applica-tions may demand effects of nonlinearity on structural response to be accounted for....... The present work deals with analytically predicting dynamic responses for nonlinear continuous elastic periodic structures. Specifically, the effects of weak nonlinearity on the dispersion re-lation and frequency band-gaps of a periodic Bernoulli-Euler beam performing bending os-cillations are analyzed......The analysis of the behaviour of linear periodic structures can be traced back over 300 years, to Sir Isaac Newton, and still attracts much attention. An essential feature of periodic struc-tures is the presence of frequency band-gaps, i.e. frequency ranges in which waves cannot propagate...

The effect of eating frequency on appetite control and food intake: brief synopsis of controlled feeding studies.

Science.gov (United States)

Leidy, Heather J; Campbell, Wayne W

2011-01-01

Increased eating frequency is postulated to increase metabolism, reduce hunger, improve glucose and insulin control, and reduce body weight, making it an enticing dietary strategy for weight loss and/or the maintenance of a healthy body weight. Because past research has primarily focused on the effects of eating frequency on changes in energy expenditure and body weight, limited data exist surrounding the impact of eating frequency on appetite control and energy intake. We provide a brief review of the controlled-feeding studies that primarily targeted the appetitive, hormonal, and food intake responses potentially altered with eating frequency. The 3 meal/d pattern served as the reference for defining increased or reduced eating frequency. In general, increased eating frequency led to lower peaks (P frequency. However, when examining these responses over the course of the day (i.e. using area under the curve assessments), no differences in any of these outcomes were observed. The rate of gastric emptying also appears to be unaltered with increased eating frequency. Subsequent food intake was examined in several studies with conflicting results. Regarding the effect of reduced eating frequency, several studies indicate significant increases in perceived appetite and reductions in perceived satiety when 1 or 2 meals were eliminated from the daily diet. Taken together, these findings suggest that increased eating frequency (>3 eating occasions/d) has minimal, if any, impact on appetite control and food intake, whereas reduced eating frequency(<3 eating occasions/d) negatively effects appetite control.

Effects of GSM-Frequency Electromagnetic Radiation on Some Physiological and Biochemical Parameters in Rats.

Science.gov (United States)

Khirazova, E E; Baizhumanov, A A; Trofimova, L K; Deev, L I; Maslova, M V; Sokolova, N A; Kudryashova, N Yu

2012-10-01

Single exposure of white outbred rats to electromagnetic radiation with a frequency 905 MHz (GSM frequency) for 2 h increased anxiety, reduced locomotor, orientation, and exploration activities in females and orientation and exploration activities in males. Glucocorticoid levels and antioxidant system activity increased in both males and females. In addition to acute effects, delayed effects of radiation were observed in both males and females 1 day after the exposure. These results demonstrated significant effect of GSM-range radiation on the behavior and activity of stress-realizing and stress-limiting systems of the body.

Effects of feed refreshing frequency on growth and carcass ...

African Journals Online (AJOL)

Sixty, two-month old male Awassi lambs were used in this study to investigate the effects of feed refreshing (FR) frequencies on their growth and carcass characteristics over a period of 65 days. Treatments were: Feed refreshing at 2 h (FR2), 4 h (FR4), 8 h (FR8), 12 h (FR12) and 24 h (FR24) intervals. The lambs were fed ...

Reliability of Laterality Effects in a Dichotic Listening Task with Words and Syllables

Science.gov (United States)

Russell, Nancy L.; Voyer, Daniel

2004-01-01

Large and reliable laterality effects have been found using a dichotic target detection task in a recent experiment using word stimuli pronounced with an emotional component. The present study tested the hypothesis that the magnitude and reliability of the laterality effects would increase with the removal of the emotional component and variations…

Effect of planecta and ROSE? on the frequency characteristics of blood pressure-transducer kits

OpenAIRE

Fujiwara, Shigeki; Kawakubo, Yoshifumi; Mori, Satoshi; Tachihara, Keiichi; Toyoguchi, Izumi; Yokoyama, Takeshi

2014-01-01

Pressure-transducer kits have frequency characteristics such as natural frequency and damping coefficient, which affect the monitoring accuracy. The aim of the present study was to investigate the effect of planecta ports and a damping device (ROSE?, Argon Medical Devices, TX, USA) on the frequency characteristics of pressure-transducer kits. The FloTrac sensor kit (Edwards Lifesciences, CA, USA) and the DTXplus transducer kit (Argon Medical Devices) were prepared with planecta ports, and the...

Word length, set size, and lexical factors: Re-examining what causes the word length effect.

Science.gov (United States)

Guitard, Dominic; Gabel, Andrew J; Saint-Aubin, Jean; Surprenant, Aimée M; Neath, Ian

2018-04-19

The word length effect, better recall of lists of short (fewer syllables) than long (more syllables) words has been termed a benchmark effect of working memory. Despite this, experiments on the word length effect can yield quite different results depending on set size and stimulus properties. Seven experiments are reported that address these 2 issues. Experiment 1 replicated the finding of a preserved word length effect under concurrent articulation for large stimulus sets, which contrasts with the abolition of the word length effect by concurrent articulation for small stimulus sets. Experiment 2, however, demonstrated that when the short and long words are equated on more dimensions, concurrent articulation abolishes the word length effect for large stimulus sets. Experiment 3 shows a standard word length effect when output time is equated, but Experiments 4-6 show no word length effect when short and long words are equated on increasingly more dimensions that previous demonstrations have overlooked. Finally, Experiment 7 compared recall of a small and large neighborhood words that were equated on all the dimensions used in Experiment 6 (except for those directly related to neighborhood size) and a neighborhood size effect was still observed. We conclude that lexical factors, rather than word length per se, are better predictors of when the word length effect will occur. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Analyzing Effect of System Inertia on Grid Frequency Forecasting Usnig Two Stage Neuro-Fuzzy System

Science.gov (United States)

Chourey, Divyansh R.; Gupta, Himanshu; Kumar, Amit; Kumar, Jitesh; Kumar, Anand; Mishra, Anup

2018-04-01

Frequency forecasting is an important aspect of power system operation. The system frequency varies with load-generation imbalance. Frequency variation depends upon various parameters including system inertia. System inertia determines the rate of fall of frequency after the disturbance in the grid. Though, inertia of the system is not considered while forecasting the frequency of power system during planning and operation. This leads to significant errors in forecasting. In this paper, the effect of inertia on frequency forecasting is analysed for a particular grid system. In this paper, a parameter equivalent to system inertia is introduced. This parameter is used to forecast the frequency of a typical power grid for any instant of time. The system gives appreciable result with reduced error.

Effect of plant spacing and weeding frequency on weed infestation ...

African Journals Online (AJOL)

Common bean is an important food and cash crop in eastern Ethiopia. However, its yield is constrained by weeds. Therefore, this study was conducted in 2012 main cropping season at Haramaya and Hirna research fields, eastern Ethiopia, to determine the effect of plant spacing and weeding frequency on weeds, yield ...

Frequency Selective Filtering of the Modulation Spectrum and its Impact on Consonant Identification

DEFF Research Database (Denmark)

Christiansen, Thomas Ulrich; Greenberg, Steven

2009-01-01

The spectro-temporal coding of Danish consonants was investigated using an information-theoretic approach. Listeners were asked to identify eleven different consonants spoken in a CV[l] syllable context (where C refers to the initial consonant, V refers to one of three vowels, [I, a, u], and [l] ...... of information-theoretic analysis can be used to delineate those parts of the speech signal of greatest importance for encoding phonetic features associated with intelligibility and speech understanding....

Speech misperception: speaking and seeing interfere differently with hearing.

Directory of Open Access Journals (Sweden)

Takemi Mochida

Full Text Available Speech perception is thought to be linked to speech motor production. This linkage is considered to mediate multimodal aspects of speech perception, such as audio-visual and audio-tactile integration. However, direct coupling between articulatory movement and auditory perception has been little studied. The present study reveals a clear dissociation between the effects of a listener's own speech action and the effects of viewing another's speech movements on the perception of auditory phonemes. We assessed the intelligibility of the syllables [pa], [ta], and [ka] when listeners silently and simultaneously articulated syllables that were congruent/incongruent with the syllables they heard. The intelligibility was compared with a condition where the listeners simultaneously watched another's mouth producing congruent/incongruent syllables, but did not articulate. The intelligibility of [ta] and [ka] were degraded by articulating [ka] and [ta] respectively, which are associated with the same primary articulator (tongue as the heard syllables. But they were not affected by articulating [pa], which is associated with a different primary articulator (lips from the heard syllables. In contrast, the intelligibility of [ta] and [ka] was degraded by watching the production of [pa]. These results indicate that the articulatory-induced distortion of speech perception occurs in an articulator-specific manner while visually induced distortion does not. The articulator-specific nature of the auditory-motor interaction in speech perception suggests that speech motor processing directly contributes to our ability to hear speech.

Effects of the frequency and satisfaction with leisure profile on dementia caregivers distress

Directory of Open Access Journals (Sweden)

Rosa Romero-Moreno

2014-10-01

Full Text Available Objectives: The PEAR (pleasant events-activity restriction model has been proposed as a way of understanding leisure effects on dementia caregivers' distress. Considering both the PEAR model and the stress and coping model, the purpose of this study was to analyze the potential of both frequency and satisfaction with leisure to explain caregivers' distress (depression, anxiety and perceived health, risk of institutionalization of the care recipient, caregivers' stressors and resources variables (rumination and cognitive reappraisal in 275 caregivers. Methods: The sample was divided in four groups based on caregivers' scores on frequency and satisfaction with leisure: LFLS = Low frequency + low satisfaction; LFHS = Low frequency and high satisfaction; HFLS = High frequency + low satisfaction; HFHS = High frequency + high satisfaction. Results: Results indicated that while caregivers from the HFHS group showed a generally more positive profile on resources variables, health outcomes and lower levels of risk of institutionalization compared with the other groups, caregivers from the LFLS group used significantly less adaptive emotional regulation strategies and showed worse consequences on health outcomes. Discussion: The results of this study suggest the importance of considering caregivers' profile on frequency and satisfaction with leisure in order to understand caregiving distress.

Perceptual effects of noise reduction by time-frequency masking of noisy speech.

Science.gov (United States)

Brons, Inge; Houben, Rolph; Dreschler, Wouter A

2012-10-01

Time-frequency masking is a method for noise reduction that is based on the time-frequency representation of a speech in noise signal. Depending on the estimated signal-to-noise ratio (SNR), each time-frequency unit is either attenuated or not. A special type of a time-frequency mask is the ideal binary mask (IBM), which has access to the real SNR (ideal). The IBM either retains or removes each time-frequency unit (binary mask). The IBM provides large improvements in speech intelligibility and is a valuable tool for investigating how different factors influence intelligibility. This study extends the standard outcome measure (speech intelligibility) with additional perceptual measures relevant for noise reduction: listening effort, noise annoyance, speech naturalness, and overall preference. Four types of time-frequency masking were evaluated: the original IBM, a tempered version of the IBM (called ITM) which applies limited and non-binary attenuation, and non-ideal masking (also tempered) with two different types of noise-estimation algorithms. The results from ideal masking imply that there is a trade-off between intelligibility and sound quality, which depends on the attenuation strength. Additionally, the results for non-ideal masking suggest that subjective measures can show effects of noise reduction even if noise reduction does not lead to differences in intelligibility.

Success-slope effects on the illusion of control and on remembered success-frequency

Directory of Open Access Journals (Sweden)

Anastasia Ejova

2013-07-01

Full Text Available The illusion of control refers to the inference of action-outcome contingency in situations where outcomes are in fact random. The strength of this illusion has been found to be affected by whether the frequency of successes increases or decreases over repeated trials, in what can be termed a ``success-slope'' effect. Previous studies have generated inconsistent findings regarding the nature of this effect. In this paper we present an experiment (N = 334 that overcomes several methodological limitations within this literature, employing a wider range of dependent measures (measures of two different types of illusory control, primary (by self and secondary (by luck, as well as measures of remembered success-frequency. Results indicate that different dependent measures lead to different effects. On measures of (primary, but not secondary control over the task, scores were highest when the rate of success increased over time. Meanwhile, estimates of success-frequency in the task did not vary across conditions and showed trends consistent with the broader literature on human memory.

The Low-Frequency Encoding Disadvantage: Word Frequency Affects Processing Demands

OpenAIRE

Diana, Rachel A.; Reder, Lynne M.

2006-01-01

Low-frequency words produce more hits and fewer false alarms than high-frequency words in a recognition task. The low-frequency hit rate advantage has sometimes been attributed to processes that operate during the recognition test (e.g., L. M. Reder et al., 2000). When tasks other than recognition, such as recall, cued recall, or associative recognition, are used, the effects seem to contradict a low-frequency advantage in memory. Four experiments are presented to support the claim that in ad...

High-frequency homogenization of zero frequency stop band photonic and phononic crystals

CERN Document Server

Antonakakis, Tryfon; Guenneau, Sebastien

2013-01-01

We present an accurate methodology for representing the physics of waves, for periodic structures, through effective properties for a replacement bulk medium: This is valid even for media with zero frequency stop-bands and where high frequency phenomena dominate. Since the work of Lord Rayleigh in 1892, low frequency (or quasi-static) behaviour has been neatly encapsulated in effective anisotropic media. However such classical homogenization theories break down in the high-frequency or stop band regime. Higher frequency phenomena are of significant importance in photonics (transverse magnetic waves propagating in infinite conducting parallel fibers), phononics (anti-plane shear waves propagating in isotropic elastic materials with inclusions), and platonics (flexural waves propagating in thin-elastic plates with holes). Fortunately, the recently proposed high-frequency homogenization (HFH) theory is only constrained by the knowledge of standing waves in order to asymptotically reconstruct dispersion curves an...

Effect of Solar Radiation on Viscoelastic Properties of Bovine Leather: Temperature and Frequency Scans

Science.gov (United States)

Nalyanya, Kallen Mulilo; Rop, Ronald K.; Onyuka, Arthur S.

2017-04-01

This work presents both analytical and experimental results of the effect of unfiltered natural solar radiation on the thermal and dynamic mechanical properties of Boran bovine leather at both pickling and tanning stages of preparation. Samples cut from both pickled and tanned pieces of leather of appropriate dimensions were exposed to unfiltered natural solar radiation for time intervals ranging from 0 h (non-irradiated) to 24 h. The temperature of the dynamic mechanical analyzer was equilibrated at 30°C and increased to 240°C at a heating rate of 5°C \\cdot Min^{-1}, while its oscillation frequency varied from 0.1 Hz to 100 Hz. With the help of thermal analysis (TA) control software which analyzes and generates parameter means/averages at temperature/frequency range, the graphs were created by Microsoft Excel 2013 from the means. The viscoelastic properties showed linear frequency dependence within 0.1 Hz to 30 Hz followed by negligible frequency dependence above 30 Hz. Storage modulus (E') and shear stress (σ ) increased with frequency, while loss modulus (E''), complex viscosity (η ^{*}) and dynamic shear viscosity (η) decreased linearly with frequency. The effect of solar radiation was evident as the properties increased initially from 0 h to 6 h of irradiation followed by a steady decline to a minimum at 18 h before a drastic increase to a maximum at 24 h. Hence, tanning industry can consider the time duration of 24 h for sun-drying of leather to enhance the mechanical properties and hence the quality of the leather. At frequencies higher than 30 Hz, the dynamic mechanical properties are independent of the frequency. The frequency of 30 Hz was observed to be a critical value in the behavior in the mechanical properties of bovine hide.

Effects of regrowth period, season and harvesting frequency on the ...

African Journals Online (AJOL)

Effects of regrowth period, season and harvesting frequency on the yield and nutritive value of Chloris gayana in the southern highlands of Tanzania. ... In vitro dry matter digestibility (IVDMD) and metabolisable energy (ME) declined faster with increasing periods of growth in the early than in the late wet season. ME ranged ...

Effects of Instantaneous Multiband Dynamic Compression on Speech Intelligibility

Directory of Open Access Journals (Sweden)

Herzke Tobias

2005-01-01

Full Text Available The recruitment phenomenon, that is, the reduced dynamic range between threshold and uncomfortable level, is attributed to the loss of instantaneous dynamic compression on the basilar membrane. Despite this, hearing aids commonly use slow-acting dynamic compression for its compensation, because this was found to be the most successful strategy in terms of speech quality and intelligibility rehabilitation. Former attempts to use fast-acting compression gave ambiguous results, raising the question as to whether auditory-based recruitment compensation by instantaneous compression is in principle applicable in hearing aids. This study thus investigates instantaneous multiband dynamic compression based on an auditory filterbank. Instantaneous envelope compression is performed in each frequency band of a gammatone filterbank, which provides a combination of time and frequency resolution comparable to the normal healthy cochlea. The gain characteristics used for dynamic compression are deduced from categorical loudness scaling. In speech intelligibility tests, the instantaneous dynamic compression scheme was compared against a linear amplification scheme, which used the same filterbank for frequency analysis, but employed constant gain factors that restored the sound level for medium perceived loudness in each frequency band. In subjective comparisons, five of nine subjects preferred the linear amplification scheme and would not accept the instantaneous dynamic compression in hearing aids. Four of nine subjects did not perceive any quality differences. A sentence intelligibility test in noise (Oldenburg sentence test showed little to no negative effects of the instantaneous dynamic compression, compared to linear amplification. A word intelligibility test in quiet (one-syllable rhyme test showed that the subjects benefit from the larger amplification at low levels provided by instantaneous dynamic compression. Further analysis showed that the increase

Effective High-Frequency Permeability of Compacted Metal Powders

Science.gov (United States)

Volkovskaya, I. I.; Semenov, V. E.; Rybakov, K. I.

2018-03-01

We propose a model for determination of the effective complex permeability of compacted metal-powder media. It is based on the equality of the magnetic moment in a given volume of the media with the desired effective permeability to the total magnetic moment of metal particles in the external high-frequency magnetic field, which arises due to excitation of electric eddy currents in the particles. Calculations within the framework of the proposed model allow us to refine the values of the real and imaginary components of the permeability of metal powder compacts in the microwave band. The conditions of applicability of the proposed model are formulated, and their fulfillment is verified for metal powder compacts in the microwave and millimeter wavelength bands.

Adjuvant low-frequency rTMS in treating auditory hallucinations in recent-onset schizophrenia: a randomized controlled study investigating the effect of high-frequency priming stimulation.

Science.gov (United States)

Ray, Prasenjit; Sinha, Vinod Kumar; Tikka, Sai Krishna

2015-01-01

Repetitive transcranial magnetic stimulation (rTMS) has been found to be effective in reducing frequency and duration of auditory verbal hallucinations (AVH). Priming stimulation, which involves high-frequency rTMS stimulation followed by low-frequency rTMS, has been shown to markedly enhance the neural response to the low-frequency stimulation train. However, this technique has not been investigated in recent onset schizophrenia patients. The aim of this randomized controlled study was to investigate whether the effects of rTMS on AVH can be enhanced with priming rTMS in recent onset schizophrenia patients. Forty recent onset schizophrenia patients completed the study. Patients were randomized over two groups: one receiving low-frequency rTMS preceded by priming and another receiving low-frequency rTMS without priming. Both treatments were directed at the left temporo-parietal region. The severity of AVH and other psychotic symptoms were assessed with the auditory hallucination subscale (AHRS) of the Psychotic Symptom Rating Scales (PSYRATS), the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impression (CGI). We found that all the scores of these ratings significantly reduced over time (i.e. baseline through 1, 2, 4 and 6 weeks) in both the treatment groups. We found no difference between the two groups on all measures, except for significantly greater improvement on loudness of AVH in the group with priming stimulation during the follow-ups (F = 2.72; p low-frequency rTMS alone and high-frequency priming of low-frequency rTMS do not elicit significant differences in treatment of overall psychopathology, particularly AVH when given in recent onset schizophrenia patients. Add on priming however, seems to be particularly better in faster reduction in loudness of AVH.

Pipeline's natural frequency response due to internal pressure effect

Energy Technology Data Exchange (ETDEWEB)

Massa, Andre L.L.; Guevara Junior, Nestor O. [Suporte - Consultoria e Projetos Ltda., Rio de Janeiro, RJ (Brazil); Galgoul, Nelson S. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Fernandes, Antonio C.; Coelho, Fabio M. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Coordenacao de Programas de Pos-graduacao de Engenharia

2009-12-19

A few years ago, a discussion about how internal pressure is treated in submarine pipelines has taken place. Galgoul et al (2004) have pointed out the conservatism of the latest recommendations for pipeline free-span evaluations associated to the way the axial force is considered in the determination of the pipeline natural frequency. Fyrileiv and Collberg (2005) have also discussed this point in defense of the effective axial force concept and its use in the natural frequency determination. In order to contribute to this aspect, an experimental test has been performed with a fully embedded pipeline which was pressurized. The main object consists in showing that the pipe is under tension (and not under compression) and, as a consequence, it is the authors' intention to prove that the natural frequency increases instead of reducing when the internal pressure is incremented. In addition to the test, a finite element model has been presented where this internal pressure effect is taken into account as it actually is (and not as an axial force) in order to show the real behavior of the wall stresses. Static analyses, as well as modal and transient analysis have been performed in order to compare theoretical results with the experimental test conducted. (author)

Sheath impedance effects in very high frequency plasma experiments

International Nuclear Information System (INIS)

Schwarzenbach, W.; Howling, A.A.; Fivaz, M.; Brunner, S.; Hollenstein, C.

1995-05-01

The frequency dependence (13.56 MHz to 70 MHz) of the ion energy distribution at the ground electrode was measured by mass spectrometry in a symmetrical capacitive argon discharge. Reduced sheath impedance at Very High Frequency allows high levels of plasma power and substrate ion flux whilst maintaining low levels of ion energy and electrode voltage. The lower limit of ion bombardment energy is fixed by the sheath floating potential at high frequency, in contrast to low frequencies where only the rf voltage amplitude is determinant. The capacitive sheaths are thinner at high frequencies which accentuates the high frequency reduction in sheath impedance. It is argued that the frequency dependence of sheath impedance is responsible for the principal characteristics of Very High Frequency plasmas. The measurements are summarised by simple physical descriptions and compared with a Particle-In-Cell simulation. (author) figs., tabs., refs

Human frequency-following response to speech-like sounds: correlates of off-frequency masking.

Science.gov (United States)

Krishnan, Ananthanarayan; Agrawal, Smita

2010-01-01

Off-frequency masking of the second formant by energy at the first formant has been shown to influence both identification and discrimination of the second formant in normal-hearing and hearing-impaired listeners. While both excitatory spread and two-tone suppression have been implicated in this simultaneous masking, their relative contribution has been shown to depend on both the level of the masker and the frequency separation between the probe and the masker. Off-frequency masking effects were evaluated in 10 normal-hearing human adults using the frequency-following response (FFR) to two two-tone approximations of vowel stimuli (/a/ and /u/). In the first experiment, the masking effect of F(1) on F(2) was evaluated by attenuating the level of F(1) relative to a fixed F(2) level. In the second experiment, the masking effect was evaluated by increasing the frequency separation between F(1) and F(2) using F(2) frequency as the variable. Results revealed that both attenuation of the F(1) level, and increasing the frequency separation between F(1) and F(2) increased the magnitude of the FFR component at F(2). These results are consistent with a release from off-frequency masking. Given that the results presented here are for high signal and masker levels and for relatively smaller frequency separation between the masker and the probe, it is possible that both suppression and excitatory spread contributed to the masking effects observed in our data. Copyright2009 S. Karger AG, Basel.

High-frequency spin-dependent tunnelling in magnetic nanocomposites: Magnetorefractive effect and magnetoimpedance

Energy Technology Data Exchange (ETDEWEB)

Granovsky, Alexander [Faculty of Physics, Lomonosov Moscow State University, Moscow 119992 (Russian Federation)]. E-mail: granov@magn.ru; Kozlov, Andrey [Faculty of Physics, Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Nedukh, Sergey [Institute of Radiophysics and Electronics NAS of Ukraine, Kharkov 61085 (Ukraine); Tarapov, Sergey [Institute of Radiophysics and Electronics NAS of Ukraine, Kharkov 61085 (Ukraine)

2005-07-15

Since the dielectric permittivity is linear with frequency-dependent conductivity, high-frequency properties for any kind of magnetic materials with the high magnetoresistance depend on magnetization. It manifests as magnetorefractive effect (MRE) in the infrared region of spectrum and as magnetoimpedance (MI) in the frequency range between radio and microwaves. The main mechanism of both MRE and MI in nanocomposites with tunnel-type magnetoresistance is high-frequency spin-dependent tunnelling. We report on recent results of theoretical and experimental investigations of MRE and MI in nanocomposites Co{sub 51.5}Al{sub 19.5}O{sub 29}, Co{sub 50.2}Ti{sub 9.1}O{sub 40.7}, Co{sub 52.3}Si{sub 12.2}O{sub 35.5} and (Co{sub 0,4}Fe{sub 0,6}){sub 48}(MgF){sub 52}. Most of the obtained experimental data for MRE and MI are consistent with the theory based on considering the tunnel junction between adjacent granules in percolation cluster as a capacitor.

Equivalent to Represent Inertial and Primary Frequency Control Effects of an External System

DEFF Research Database (Denmark)

Weckesser, Johannes Tilman Gabriel; Van Cutsem, Thierry

2017-01-01

This paper presents a novel equivalent, which is suitable for simulation of inertial and primary frequency control effects. In the model reduction procedure, dynamic power injectors are used to replace the external system and to mimic its dynamic behavior. The parameters of the equivalents...... are tuned with a simple approach presented in this paper. The effectiveness of the proposed method is demonstrated on a modified version of the ENTSO-E Dynamic Study Model. The results show that the system frequency response of the unreduced system is retained and a speedup of the simulations of around 4...

Effect of Low Frequency Burner Vibrations on the Characteristics of Jet Diffusion Flames

Directory of Open Access Journals (Sweden)

C. Kanthasamy

2012-03-01

Full Text Available Mechanical vibrations introduced in diffusion flame burners significantly affect the flame characteristics. In this experimental study, the effects of axial vibrations on the characteristics of laminar diffusion flames are investigated systematically. The effect of the frequency and amplitude of the vibrations on the flame height oscillations and flame stability is brought out. The amplitude of flame height oscillations is found to increase with increase in both frequency and amplitude of burner vibrations. Vibrations are shown to enhance stability of diffusion flames. Although flame lifts-off sooner with vibrations, stability of the flame increases.

Pulse amplitude and frequency effects in a pulsed packed column

Energy Technology Data Exchange (ETDEWEB)

Russell, S H

1954-04-15

A study has been made of the effect on the efficiency and capacity of applying pulses of varying amplitude and frequency to a packed column. In the efficiency studies, the maximum efficiency was obtained with a pulse having an amplitude of 3/8'' and a frequency of 140 cycles per minute. Under these conditions, the column was about five times as efficient as a simple packed column. Two general types of results were obtained in the capacity studies. Under certain conditions, the capacity increased over that of a simple packed column, but under others, it decreased. Some of the factors causing this were investigated but the fundamental reasons were not determined due to a lack of personnel for the necessary experiments. (author)

Pulse amplitude and frequency effects in a pulsed packed column

International Nuclear Information System (INIS)

Russell, S.H.

1954-04-01

A study has been made of the effect on the efficiency and capacity of applying pulses of varying amplitude and frequency to a packed column. In the efficiency studies, the maximum efficiency was obtained with a pulse having an amplitude of 3/8'' and a frequency of 140 cycles per minute. Under these conditions, the column was about five times as efficient as a simple packed column. Two general types of results were obtained in the capacity studies. Under certain conditions, the capacity increased over that of a simple packed column, but under others, it decreased. Some of the factors causing this were investigated but the fundamental reasons were not determined due to a lack of personnel for the necessary experiments. (author)

Effects of vibration frequency on vibration-assisted nano-scratch process of mono-crystalline copper via molecular dynamics simulation

Directory of Open Access Journals (Sweden)

Bo Zhu

2016-03-01

Full Text Available It has always been a critical issue to understand the material removal behavior of Vibration-Assisted Machining (VAM, especially on atomic level. To find out the effects of vibration frequency on material removal response, a three-dimensional molecular dynamics (MD model has been established in this research to investigate the effects of scratched groove, crystal defects on the surface quality, comparing with the Von Mises shear strain and tangential force in simulations during nano-scratching process. Comparisons are made among the results of simulations from different vibration frequency with the same scratching feed, depth, amplitude and crystal orientation. Copper potential in this simulation is Embedded-Atom Method (EAM potential. Interaction between copper and carbon atoms is Morse potential. Simulational results show that higher frequency can make groove smoother. Simulation with high frequency creates more dislocations to improve the machinability of copper specimen. The changing frequency does not have evident effects on Von Mises shear strain. Higher frequency can decrease the tangential force to reduce the consumption of cutting energy and tool wear. In conclusion, higher vibration frequency in VAM on mono-crystalline copper has positive effects on surface finish, machinablility and tool wear reduction.

Effects of vibration frequency on vibration-assisted nano-scratch process of mono-crystalline copper via molecular dynamics simulation

Energy Technology Data Exchange (ETDEWEB)

Zhu, Bo; Zhao, Hongwei, E-mail: hwzhao@jlu.edu.cn, E-mail: khl69@163.com; Zhao, Dan; Zhang, Peng; Yang, Yihan; Han, Lei [School of Mechanical Science and Engineering, Jilin University, 5988 Renmin Street, Changchun, Jilin 130025 (China); Kui, Hailin, E-mail: hwzhao@jlu.edu.cn, E-mail: khl69@163.com [School of Transportation, Jilin University, 5988 Renmin Street, Changchun, Jilin 130025 (China)

2016-03-15

It has always been a critical issue to understand the material removal behavior of Vibration-Assisted Machining (VAM), especially on atomic level. To find out the effects of vibration frequency on material removal response, a three-dimensional molecular dynamics (MD) model has been established in this research to investigate the effects of scratched groove, crystal defects on the surface quality, comparing with the Von Mises shear strain and tangential force in simulations during nano-scratching process. Comparisons are made among the results of simulations from different vibration frequency with the same scratching feed, depth, amplitude and crystal orientation. Copper potential in this simulation is Embedded-Atom Method (EAM) potential. Interaction between copper and carbon atoms is Morse potential. Simulational results show that higher frequency can make groove smoother. Simulation with high frequency creates more dislocations to improve the machinability of copper specimen. The changing frequency does not have evident effects on Von Mises shear strain. Higher frequency can decrease the tangential force to reduce the consumption of cutting energy and tool wear. In conclusion, higher vibration frequency in VAM on mono-crystalline copper has positive effects on surface finish, machinablility and tool wear reduction.

Experimental investigation of the effects of high-frequency electroactive morphing on the shear-layer

Science.gov (United States)

Scheller, Johannes; Rizzo, Karl-Joseph; Jodin, Gurvan; Duhayon, Eric; Rouchon, Jean-François; Hunt, Julian; Braza, Marianna

2015-11-01

Time-resolved PIV measurements are conducted at a Reynolds number of 270 . 000 downstream of the trailing edge of a NACA4412 airfoil equipped with trailing-edge piezoelectric tab actuators to investigate the high-frequency low-amplitude actuation's effect on the shear-layer. A comparison of the time-averaged Reynolds stress tensor components at different actuation frequency reveals a significant impact of the actuation on the shear-layer dynamics. A proper orthogonal decomposition analysis is conducted in order to investigate the actuation's impact on the vortex breakdown. It will be shown that a specific low-amplitude actuation frequency enables a reduction of the predominant shear-layer frequencies.

Effect of Radio-Frequency and Low-Frequency Bias Voltage on the Formation of Amorphous Carbon Films Deposited by Plasma Enhanced Chemical Vapor Deposition

International Nuclear Information System (INIS)

Manis-Levy, Hadar; Mintz, Moshe H.; Livneh, Tsachi; Zukerman Ido; Raveh, Avi

2014-01-01

The effect of radio-frequency (RF) or low-frequency (LF) bias voltage on the formation of amorphous hydrogenated carbon (a-C:H) films was studied on silicon substrates with a low methane (CH 4 ) concentration (2–10 vol.%) in CH 4 +Ar mixtures. The bias substrate was applied either by RF (13.56 MHz) or by LF (150 kHz) power supply. The highest hardness values (∼18–22 GPa) with lower hydrogen content in the films (∼20 at.%) deposited at 10 vol.% CH 4 , was achieved by using the RF bias. However, the films deposited using the LF bias, under similar RF plasma generation power and CH 4 concentration (50 W and 10 vol.%, respectively), displayed lower hardness (∼6–12 GPa) with high hydrogen content (∼40 at.%). The structures analyzed by Fourier Transform Infrared (FTIR) and Raman scattering measurements provide an indication of trans-polyacetylene structure formation. However, its excessive formation in the films deposited by the LF bias method is consistent with its higher bonded hydrogen concentration and low level of hardness, as compared to the film prepared by the RF bias method. It was found that the effect of RF bias on the film structure and properties is stronger than the effect of the low-frequency (LF) bias under identical radio-frequency (RF) powered electrode and identical PECVD (plasma enhanced chemical vapor deposition) system configuration. (plasma technology)

Effects of frequency on gross efficiency and performance in roller ski skating.

Science.gov (United States)

Leirdal, S; Sandbakk, O; Ettema, G

2013-06-01

The purpose of the present study was to examine the effect of frequency on efficiency and performance during G3 roller ski skating. Eight well-trained male cross-country skiers performed three submaximal 5-min speeds (10, 13, and 16 km/h) and a time-to-exhaustion (TTE) performance (at 20 km/h) using the G3 skating technique using freely chosen, high, and low frequency at all four speeds. All tests were done using roller skis on a large treadmill at 5% incline. Gross efficiency (GE) was calculated as power divided by metabolic rate. Power was calculated as the sum of power against frictional forces and power against gravity. Metabolic rate was calculated from oxygen consumption and blood lactate concentration. Freely chosen frequency increased from 60 to 70 strokes/min as speed increased from 10 to 20 km/h. GE increased with power. At high power (20 km/h performance test), both efficiency and performance were significantly reduced by high frequency. In regard to choice of frequency during G3 roller ski skating, cross-country skiers seems to be self-optimized both in relation to energy saving (efficiency) and performance (TTE). © 2011 John Wiley & Sons A/S.

Effect of higher frequency on the classification of steady-state visual evoked potentials

Science.gov (United States)

Won, Dong-Ok; Hwang, Han-Jeong; Dähne, Sven; Müller, Klaus-Robert; Lee, Seong-Whan

2016-02-01

Objective. Most existing brain-computer interface (BCI) designs based on steady-state visual evoked potentials (SSVEPs) primarily use low frequency visual stimuli (e.g., visual fatigue and no stimulus-related seizures. The fundamental objective of this study was to investigate the effect of stimulation frequency and duty-cycle on the usability of an SSVEP-based BCI system. Approach. We developed an SSVEP-based BCI speller using multiple LEDs flickering with low frequencies (6-14.9 Hz) with a duty-cycle of 50%, or higher frequencies (26-34.7 Hz) with duty-cycles of 50%, 60%, and 70%. The four different experimental conditions were tested with 26 subjects in order to investigate the impact of stimulation frequency and duty-cycle on performance and visual fatigue, and evaluated with a questionnaire survey. Resting state alpha powers were utilized to interpret our results from the neurophysiological point of view. Main results. The stimulation method employing higher frequencies not only showed less visual fatigue, but it also showed higher and more stable classification performance compared to that employing relatively lower frequencies. Different duty-cycles in the higher frequency stimulation conditions did not significantly affect visual fatigue, but a duty-cycle of 50% was a better choice with respect to performance. The performance of the higher frequency stimulation method was also less susceptible to resting state alpha powers, while that of the lower frequency stimulation method was negatively correlated with alpha powers. Significance. These results suggest that the use of higher frequency visual stimuli is more beneficial for performance improvement and stability as time passes when developing practical SSVEP-based BCI applications.

Disentangling the Effects of Precipitation Amount and Frequency on the Performance of 14 Grassland Species

Science.gov (United States)

Didiano, Teresa J.; Johnson, Marc T. J.; Duval, Tim P.

2016-01-01

Climate change is causing shifts in the amount and frequency of precipitation in many regions, which is expected to have implications for plant performance. Most research has examined the impacts of the amount of precipitation on plants rather than the effects of both the amount and frequency of precipitation. To understand how climate-driven changes in precipitation can affect grassland plants, we asked: (i) How does the amount and frequency of precipitation affect plant performance? (ii) Do plant functional groups vary in their response to variable precipitation? To answer these questions we grew 14 monocot and eudicot grassland species and conducted a factorial manipulation of the amount (70 vs 90mm/month) and frequency (every 3, 15, or 30 days) of precipitation under rainout shelters. Our results show that both the amount and frequency of precipitation impact plant performance, with larger effects on eudicots than monocots. Above- and below-ground biomass were affected by the amount of precipitation and/or the interaction between the amount and frequency of precipitation. Above-ground biomass increased by 21–30% when the amount of precipitation was increased. When event frequency was decreased from 3 to 15 or 30 days, below-ground biomass generally decreased by 18–34% in the 70 mm treatment, but increased by 33–40% in the 90 mm treatment. Changes in stomatal conductance were largely driven by changes in event frequency. Our results show that it is important to consider changes in both the amount and frequency of precipitation when predicting how plant communities will respond to variable precipitation. PMID:27622497

Nonthermal effects of therapeutic ultrasound: the frequency resonance hypothesis.

Science.gov (United States)

Johns, Lennart D

2002-07-01

To present the frequency resonance hypothesis, a possible mechanical mechanism by which treatment with non-thermal levels of ultrasound stimulates therapeutic effects. The review encompasses a 4-decade history but focuses on recent reports describing the effects of nonthermal therapeutic levels of ultrasound at the cellular and molecular levels. A search of MEDLINE from 1965 through 2000 using the terms ultrasound and therapeutic ultrasound. The literature provides a number of examples in which exposure of cells to therapeutic ultrasound under nonthermal conditions modified cellular functions. Nonthermal levels of ultrasound are reported to modulate membrane properties, alter cellular proliferation, and produce increases in proteins associated with inflammation and injury repair. Combined, these data suggest that nonthermal effects of therapeutic ultrasound can modify the inflammatory response. The concept of the absorption of ultrasonic energy by enzymatic proteins leading to changes in the enzymes activity is not novel. However, recent reports demonstrating that ultrasound affects enzyme activity and possibly gene regulation provide sufficient data to present a probable molecular mechanism of ultrasound's nonthermal therapeutic action. The frequency resonance hypothesis describes 2 possible biological mechanisms that may alter protein function as a result of the absorption of ultrasonic energy. First, absorption of mechanical energy by a protein may produce a transient conformational shift (modifying the 3-dimensional structure) and alter the protein's functional activity. Second, the resonance or shearing properties of the wave (or both) may dissociate a multimolecular complex, thereby disrupting the complex's function. This review focuses on recent studies that have reported cellular and molecular effects of therapeutic ultrasound and presents a mechanical mechanism that may lead to a better understanding of how the nonthermal effects of ultrasound may be

Application of electrolyzer system to enhance frequency stabilization effect of microturbine in a microgrid system

Energy Technology Data Exchange (ETDEWEB)

Vachirasricirikul, Sitthidet [Department of Electrical Engineering, Faculty of Engineering, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand); Ngamroo, Issarachai; Kaitwanidvilai, Somyot [Center of Excellence for Innovative Energy Systems, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand)

2009-09-15

It is well known that the power output of microturbine can be controlled to compensate for load change and alleviate the system frequency fluctuations. Nevertheless, the microturbine may not adequately compensate rapid load change due to its slow dynamic response. Moreover, when the intermittent power generations from wind power and photovoltaic are integrated into the system, they may cause severe frequency fluctuation. In order to study the fast dynamic response, this paper applies electrolyzer system to absorb these power fluctuations and enhance the frequency control effect of microturbine in the microgrid system. The robust coordinated controller of electrolyzer and microturbine for frequency stabilization is designed based on a fixed-structure H{sub {infinity}} loop shaping control. Simulation results exhibit the robustness and stabilizing effects of the proposed coordinated electrolyzer and microturbine controllers against system parameters variation and various operating conditions. (author)

Listening Natively across Perceptual Domains?

Science.gov (United States)

Langus, Alan; Seyed-Allaei, Shima; Uysal, Ertugrul; Pirmoradian, Sahar; Marino, Caterina; Asaadi, Sina; Eren, Ömer; Toro, Juan M.; Peña, Marcela; Bion, Ricardo A. H.; Nespor, Marina

2016-01-01

Our native tongue influences the way we perceive other languages. But does it also determine the way we perceive nonlinguistic sounds? The authors investigated how speakers of Italian, Turkish, and Persian group sequences of syllables, tones, or visual shapes alternating in either frequency or duration. We found strong native listening effects…

Neural representation of the sensorimotor speech-action-repository

Directory of Open Access Journals (Sweden)

Cornelia eEckers

2013-04-01

Full Text Available A speech-action-repository (SAR or mental syllabary has been proposed as a central module for sensorimotor processing of syllables. In this approach, syllables occurring frequently within language are assumed to be stored as holistic sensorimotor patterns, while non-frequent syllables need to be assembled from sub-syllabic units. Thus, frequent syllables are processed efficiently and quickly during production or perception by a direct activation of their sensorimotor patterns. Whereas several behavioral psycholinguistic studies provided evidence in support of the existence of a syllabary, fMRI studies have failed to demonstrate its neural reality. In the present fMRI study a reaction paradigm using homogeneous vs. heterogeneous syllable blocks are used during overt vs. covert speech production and auditory vs. visual presentation modes. Two complementary data analyses were performed: (1 in a logical conjunction, activation for syllable processing independent of input modality and response mode was assessed, in order to support the assumption of existence of a supramodal hub within a SAR. (2 In addition priming effects in the BOLD response in homogeneous vs. heterogeneous blocks were measured in order to identify brain regions, which indicate reduced activity during multiple production/perception repetitions of a specific syllable in order to determine state maps. Auditory-visual conjunction analysis revealed an activation network comprising bilateral precentral gyrus and left inferior frontal gyrus (area 44. These results are compatible with the notion of a supramodal hub within the SAR. The main effect of homogeneity priming revealed an activation pattern of areas within frontal, temporal, and parietal lobe. These findings are taken to represent sensorimotor state maps of the SAR. In conclusion, the present study provided preliminary evidence for a SAR.

Effect of porosity and pore morphology on the low-frequency ...

Indian Academy of Sciences (India)

Effect of porosity and pore size distribution on the low-frequency dielectric response, in the range 0.01-100 kHz, in sintered ZrO2-8 mol% Y2O3 ceramic compacts have been investigated. Small-angle neutron scattering (SANS) technique has been employed to obtain the pore characteristics like pore size distribution, ...

Peak effect in surface resistance at microwave frequencies in Dy ...

Indian Academy of Sciences (India)

In the measurements at both frequencies the induced microwave current was always less than the critical current of the films. The reason for observation of this peak effect in these films has been explained in our earlier publication [5]. Comparing figures 1 and 2, it is observed that the peaks in sample S1 are broader and.

Modulation infrared thermometry of caloric effects at up to kHz frequencies

Science.gov (United States)

Döntgen, Jago; Rudolph, Jörg; Waske, Anja; Hägele, Daniel

2018-03-01

We present a novel non-contact method for the direct measurement of caloric effects in low volume samples. The adiabatic temperature change ΔT of a magnetocaloric sample is very sensitively determined from thermal radiation. Rapid modulation of ΔT is induced by an oscillating external magnetic field. Detection of thermal radiation with a mercury-cadmium-telluride detector allows for measurements at field frequencies exceeding 1 kHz. In contrast to thermoacoustic methods, our method can be employed in vacuum which enhances adiabatic conditions especially in the case of small volume samples. Systematic measurements of the magnetocaloric effect as a function of temperature, magnetic field amplitude, and modulation frequency give a detailed picture of the thermal behavior of the sample. Highly sensitive measurements of the magnetocaloric effect are demonstrated on a 2 mm thick sample of gadolinium and a 60 μm thick Fe80B12Nb8 ribbon.

Lexical tone and stuttering in Cantonese.

Science.gov (United States)

Law, Thomas; Packman, Ann; Onslow, Mark; To, Carol K-S; Tong, Michael C-F; Lee, Kathy Y-S

2018-01-01

Cantonese is a tone language, in which the variation of the fundamental frequency contour of a syllable can change meaning. There are six different lexical tones in Cantonese. While research with Western languages has shown an association between stuttering and syllabic stress, nothing is known about whether stuttering in Cantonese speakers is associated with one or more of the six lexical tones. Such an association has been reported in conversational speech in Mandarin, which is also a tone language, but which varies markedly from Cantonese. Twenty-four native Cantonese-speaking adults who stutter participated in this study, ranging in age from 18-33 years. There were 18 men and 6 women. Participants read aloud 13 Cantonese syllables, each of which was produced with six contrastive lexical tones. All 78 syllables were embedded in the same carrier sentence, to reduce the influence of suprasegmental or linguistic stress, and were presented in random order. No significant differences were found for stuttering moments across the six lexical tones. It is suggested that this is because lexical tones, at least in Cantonese, do not place the task demands on the speech motor system that typify varying syllabic stress in Western languages: variations not only in fundamental frequency, but also in duration and intensity. The findings of this study suggest that treatments for adults who stutter in Western languages, such as speech restructuring, can be used with Cantonese speakers without undue attention to lexical tone.

FREQUENCY MODULATION OF DIRECTLY IMAGED EXOPLANETS: GEOMETRIC EFFECT AS A PROBE OF PLANETARY OBLIQUITY

Energy Technology Data Exchange (ETDEWEB)

Kawahara, Hajime, E-mail: kawahara@eps.s.u-tokyo.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, Tokyo 113-0033 (Japan); Research Center for the Early Universe, School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)

2016-05-10

We consider the time–frequency analysis of a scattered light curve of a directly imaged exoplanet. We show that the geometric effect due to planetary obliquity and orbital inclination induce the frequency modulation of the apparent diurnal periodicity. We construct a model of the frequency modulation and compare it with the instantaneous frequency extracted from the pseudo-Wigner distribution of simulated light curves of a cloudless Earth. The model provides good agreement with the simulated modulation factor, even for the light curve with Gaussian noise comparable to the signal. Notably, the shape of the instantaneous frequency is sensitive to the difference between the prograde, retrograde, and pole-on spin rotations. While our technique requires the albedo map to be static, it does not need to solve the albedo map of the planet. The time–frequency analysis is complementary to other methods which utilize the amplitude modulation. This paper demonstrates the importance of the frequency domain of the photometric variability for the characterization of directly imaged exoplanets in future research.

Frequency of the cancer-resistant phenotype in SR/CR mice and the effect of litter seriation

DEFF Research Database (Denmark)

Koch, Janne; Boschian, Anna; Hau, Jann

2008-01-01

. The frequency of the SR/CR phenotype in the present study was 30% for the BALB/c strain and 22% for the C57BL/6 strain in the first litters, but the overall frequency was 8% for both strains. A frequency of about 30% was reported in the original US colony. A litter seriation effect on the frequency of the SR....../CR phenotype was recorded. The phenotype frequency in the first-born litters was similar to that recorded in the founder colony in the US. There was no significant difference in the frequency of the SR/CR phenotype between the two genders, but the overall frequency of the SR/CR phenotype was significantly...

The Effect of Frequency of Input-Enhancements on Word Learning and Text Comprehension

Science.gov (United States)

Rott, Susanne

2007-01-01

Research on second language lexical development during reading has found positive effects for word frequency, the provision of glosses, and elaborative word processing. However, findings have been inconclusive regarding the effect of such intervention tasks on long-term retention. Likewise, few studies have looked at the cumulative effect of…

Distinct ERP Signatures of Word Frequency, Phrase Frequency, and Prototypicality in Speech Production

Science.gov (United States)

Hendrix, Peter; Bolger, Patrick; Baayen, Harald

2017-01-01

Recent studies have documented frequency effects for word n-grams, independently of word unigram frequency. Further studies have revealed constructional prototype effects, both at the word level as well as for phrases. The present speech production study investigates the time course of these effects for the production of prepositional phrases in…

Measurements of time average series resonance effect in capacitively coupled radio frequency discharge plasma

International Nuclear Information System (INIS)

Bora, B.; Bhuyan, H.; Favre, M.; Wyndham, E.; Chuaqui, H.; Kakati, M.

2011-01-01

Self-excited plasma series resonance is observed in low pressure capacitvely coupled radio frequency discharges as high-frequency oscillations superimposed on the normal radio frequency current. This high-frequency contribution to the radio frequency current is generated by a series resonance between the capacitive sheath and the inductive and resistive bulk plasma. In this report, we present an experimental method to measure the plasma series resonance in a capacitively coupled radio frequency argon plasma by modifying the homogeneous discharge model. The homogeneous discharge model is modified by introducing a correction factor to the plasma resistance. Plasma parameters are also calculated by considering the plasma series resonances effect. Experimental measurements show that the self-excitation of the plasma series resonance, which arises in capacitive discharge due to the nonlinear interaction of plasma bulk and sheath, significantly enhances both the Ohmic and stochastic heating. The experimentally measured total dissipation, which is the sum of the Ohmic and stochastic heating, is found to increase significantly with decreasing pressure.

Stabilizing effects of hot electrons on low frequency plasma drift waves

International Nuclear Information System (INIS)

Huang Chaosong; Qiu Lijian; Ren Zhaoxing

1988-01-01

The MHD equation is used to study the stabilization of low frequency drift waves driven by density gradient of plasma in a hot electron plasma. The dispersion relation is derived, and the stabilizing effects of hot electrons are discussed. The physical mechanism for hot electron stabilization of the low frequency plasma perturbations is charge uncovering due to the hot electron component, which depends only on α, the ratio of N h /N i , but not on the value of β h . The hot electrons can reduce the growth rate of the interchange mode and drift wave driven by the plasma, and suppress the enomalous plasma transport caused by the drift wave. Without including the effectof β h , the stabilization of the interchange mode requires α≅2%, and the stabilization of the drift wave requires α≅40%. The theoretical analyses predict that the drift wave is the most dangerous low frequency instability in the hot electron plasma

Effects of Sound Frequency on Audiovisual Integration: An Event-Related Potential Study.

Science.gov (United States)

Yang, Weiping; Yang, Jingjing; Gao, Yulin; Tang, Xiaoyu; Ren, Yanna; Takahashi, Satoshi; Wu, Jinglong

2015-01-01

A combination of signals across modalities can facilitate sensory perception. The audiovisual facilitative effect strongly depends on the features of the stimulus. Here, we investigated how sound frequency, which is one of basic features of an auditory signal, modulates audiovisual integration. In this study, the task of the participant was to respond to a visual target stimulus by pressing a key while ignoring auditory stimuli, comprising of tones of different frequencies (0.5, 1, 2.5 and 5 kHz). A significant facilitation of reaction times was obtained following audiovisual stimulation, irrespective of whether the task-irrelevant sounds were low or high frequency. Using event-related potential (ERP), audiovisual integration was found over the occipital area for 0.5 kHz auditory stimuli from 190-210 ms, for 1 kHz stimuli from 170-200 ms, for 2.5 kHz stimuli from 140-200 ms, 5 kHz stimuli from 100-200 ms. These findings suggest that a higher frequency sound signal paired with visual stimuli might be early processed or integrated despite the auditory stimuli being task-irrelevant information. Furthermore, audiovisual integration in late latency (300-340 ms) ERPs with fronto-central topography was found for auditory stimuli of lower frequencies (0.5, 1 and 2.5 kHz). Our results confirmed that audiovisual integration is affected by the frequency of an auditory stimulus. Taken together, the neurophysiological results provide unique insight into how the brain processes a multisensory visual signal and auditory stimuli of different frequencies.

Locus of Word Frequency Effects in Spelling to Dictation: Still at the Orthographic Level!

Science.gov (United States)

Bonin, Patrick; Laroche, Betty; Perret, Cyril

2016-01-01

The present study was aimed at testing the locus of word frequency effects in spelling to dictation: Are they located at the level of spoken word recognition (Chua & Rickard Liow, 2014) or at the level of the orthographic output lexicon (Delattre, Bonin, & Barry, 2006)? Words that varied on objective word frequency and on phonological…

Binding and unbinding the auditory and visual streams in the McGurk effect.

Science.gov (United States)

Nahorna, Olha; Berthommier, Frédéric; Schwartz, Jean-Luc

2012-08-01

Subjects presented with coherent auditory and visual streams generally fuse them into a single percept. This results in enhanced intelligibility in noise, or in visual modification of the auditory percept in the McGurk effect. It is classically considered that processing is done independently in the auditory and visual systems before interaction occurs at a certain representational stage, resulting in an integrated percept. However, some behavioral and neurophysiological data suggest the existence of a two-stage process. A first stage would involve binding together the appropriate pieces of audio and video information before fusion per se in a second stage. Then it should be possible to design experiments leading to unbinding. It is shown here that if a given McGurk stimulus is preceded by an incoherent audiovisual context, the amount of McGurk effect is largely reduced. Various kinds of incoherent contexts (acoustic syllables dubbed on video sentences or phonetic or temporal modifications of the acoustic content of a regular sequence of audiovisual syllables) can significantly reduce the McGurk effect even when they are short (less than 4 s). The data are interpreted in the framework of a two-stage "binding and fusion" model for audiovisual speech perception.

The effect of classical and quantum dynamics on vibrational frequency shifts of H2 in clathrate hydrates

International Nuclear Information System (INIS)

Plattner, Nuria; Meuwly, Markus

2014-01-01

Vibrational frequency shifts of H 2 in clathrate hydrates are important to understand the properties and elucidate details of the clathrate structure. Experimental spectra of H 2 in clathrate hydrates have been measured for different clathrate compositions, temperatures, and pressures. In order to establish reliable relationships between the clathrate structure, dynamics, and observed frequencies, calculations of vibrational frequency shifts in different clathrate environments are required. In this study, a combination of classical molecular dynamics simulations, electronic structure calculations, and quantum dynamical simulation is used to calculate relative vibrational frequencies of H 2 in clathrate hydrates. This approach allows us to assess dynamical effects and simulate the change of vibrational frequencies with temperature and pressure. The frequency distributions of the H 2 vibrations in the different clathrate cage types agree favorably with experiment. Also, the simulations demonstrate that H 2 in the 5 12 cage is more sensitive to the details of the environment and to quantum dynamical effects, in particular when the cage is doubly occupied. We show that for the 5 12 cage quantum effects lead to frequency increases and double occupation is unlikely. This is different for the 5 12 6 4 cages for which higher occupation numbers than one H 2 per cage are likely

Extremely low frequencies. Health effects of extremely low frequency electromagnetic fields. Opinion of the Afsset. Collective expertise report

International Nuclear Information System (INIS)

Bounouh, Alexandre; Brugere, Henri; Clavel, Jacqueline; Febvre, Pascal; Lagroye, Isabelle; Vecchia, Paolo; Dore, Jean-Francois; Anfosso-Ledee, Fabienne; Berengier, Michel; Cesarini, Jean-Pierre; Cohen, Jean-Claude; Planton, Serge; Courant, Daniel; Tardif, Francois; Couturier, Frederic; Debouzy, Jean-Claude; El Khatib, Aicha; Flahaut, Emmanuel; Gaffet, Eric; Hours, Martine; Lambert, Jacques; Vallet, Michel; Job, Agnes; Labeyrie, Antoine; Laurier, Dominique; Le Bihan, Olivier; Lepoutre, Philippe; Marchal, Didier; Moch, Annie; Pirard, Philipe; Rumeau, Michel; De Seze, Rene; Attia, Dina; Merckel, Olivier; Fite, Johanna; Guichard, Alexandra; Saihi, Myriam; Guitton, Sophie; Saddoki, Sophia

2010-03-01

This report aims at proposing a synthesis of works of international expertise on the health effect of extremely low frequency electromagnetic fields, at performing a methodological analysis of the 'Expers' study (a study on the exposure of individuals), at performing a methodological analysis of a study performed by the Criirem in the western part of France, at assessing the contribution of different equipment and situations to the exposure of population to extremely-low-frequency electromagnetic fields, at making recommendations and proposals for a better assessment of the exposure level, and at proposing topics of investigation and research to improve knowledge on these issues. The report recalls the context, scope and modalities of the study, gives an overview of generalities on electromagnetic fields (nature, physical values, electromagnetic spectrum, artificial and natural electromagnetic field sources, exposure threshold values and regulatory context), addresses the assessment of exposure (notion of exposure, exposure assessment methods, analysis of available data, analysis of recent or current studies), gives an overview of biological and health effects of these electromagnetic fields (methodological aspects, interaction between fields and biological tissues, synthesis of the international expertise on health impacts). Recommendations are formulated

Frequency Selection for Multi-frequency Acoustic Measurement of Suspended Sediment

Science.gov (United States)

Chen, X.; HO, H.; Fu, X.

2017-12-01

Multi-frequency acoustic measurement of suspended sediment has found successful applications in marine and fluvial environments. Difficult challenges remain in regard to improving its effectiveness and efficiency when applied to high concentrations and wide size distributions in rivers. We performed a multi-frequency acoustic scattering experiment in a cylindrical tank with a suspension of natural sands. The sands range from 50 to 600 μm in diameter with a lognormal size distribution. The bulk concentration of suspended sediment varied from 1.0 to 12.0 g/L. We found that the commonly used linear relationship between the intensity of acoustic backscatter and suspended sediment concentration holds only at sufficiently low concentrations, for instance below 3.0 g/L. It fails at a critical value of concentration that depends on measurement frequency and the distance between the transducer and the target point. Instead, an exponential relationship was found to work satisfactorily throughout the entire range of concentration. The coefficient and exponent of the exponential function changed, however, with the measuring frequency and distance. Considering the increased complexity of inverting the concentration values when an exponential relationship prevails, we further analyzed the relationship between measurement error and measuring frequency. It was also found that the inversion error may be effectively controlled within 5% if the frequency is properly set. Compared with concentration, grain size was found to heavily affect the selection of optimum frequency. A regression relationship for optimum frequency versus grain size was developed based on the experimental results.

The effect of feeding frequency on growth performance and body ...

African Journals Online (AJOL)

This study was done to investigate the effects of different feeding frequencies on the growth, feed efficiency and specific growth rate (%) of juvenile of rainbow trout (Oncorhynchus mykiss, weight 16.44±0.22 g) rearing in cold sea water conditions (5.8 to 9.3°C; 17 to 18 ppt). Fish were fed on a commercial feed to the apparent ...

Effect of outer hair cell piezoelectricity on high-frequency receptor potentials.

Science.gov (United States)

Spector, Alexander A; Brownell, William E; Popel, Aleksander S

2003-01-01

The low-pass voltage response of outer hair cells predicted by conventional equivalent circuit analysis would preclude the active force production at high frequencies. We have found that the band pass characteristics can be improved by introducing the piezoelectric properties of the cell wall. In contrast to the conventional analysis, the receptor potential does not tend to zero and at any frequency is greater than a limiting value. In addition, the phase shift between the transduction current and receptor potential tends to zero. The piezoelectric properties cause an additional, strain-dependent, displacement current in the cell wall. The wall strain is estimated on the basis of a model of the cell deformation in the organ of Corti. The limiting value of the receptor potential depends on the ratio of a parameter determined by the piezoelectric coefficients and the strain to the membrane capacitance. In short cells, we have found that for the low-frequency value of about 2-3 mV and the strain level of 0.1% the receptor potential can reach 0.4 mV throughout the whole frequency range. In long cells, we have found that the effect of the piezoelectric properties is much weaker. These results are consistent with major features of the cochlear amplifier.

Bias Errors due to Leakage Effects When Estimating Frequency Response Functions

Directory of Open Access Journals (Sweden)

Andreas Josefsson

2012-01-01

Full Text Available Frequency response functions are often utilized to characterize a system's dynamic response. For a wide range of engineering applications, it is desirable to determine frequency response functions for a system under stochastic excitation. In practice, the measurement data is contaminated by noise and some form of averaging is needed in order to obtain a consistent estimator. With Welch's method, the discrete Fourier transform is used and the data is segmented into smaller blocks so that averaging can be performed when estimating the spectrum. However, this segmentation introduces leakage effects. As a result, the estimated frequency response function suffers from both systematic (bias and random errors due to leakage. In this paper the bias error in the H1 and H2-estimate is studied and a new method is proposed to derive an approximate expression for the relative bias error at the resonance frequency with different window functions. The method is based on using a sum of real exponentials to describe the window's deterministic autocorrelation function. Simple expressions are derived for a rectangular window and a Hanning window. The theoretical expressions are verified with numerical simulations and a very good agreement is found between the results from the proposed bias expressions and the empirical results.

Effects of Foot Strike and Step Frequency on Achilles Tendon Stress During Running.

Science.gov (United States)

Lyght, Michael; Nockerts, Matthew; Kernozek, Thomas W; Ragan, Robert

2016-08-01

Achilles tendon (AT) injuries are common in runners. The AT withstands high magnitudes of stress during running which may contribute to injury. Our purpose was to examine the effects of foot strike pattern and step frequency on AT stress and strain during running utilizing muscle forces based on a musculoskeletal model and subject-specific ultrasound-derived AT cross-sectional area. Nineteen female runners performed running trials under 6 conditions, including rearfoot strike and forefoot strike patterns at their preferred cadence, +5%, and -5% preferred cadence. Rearfoot strike patterns had less peak AT stress (P forefoot strike pattern. A reduction in peak AT stress and strain were exhibited with a +5% preferred step frequency relative to the preferred condition using a rearfoot (P forefoot (P=.005) strike pattern. Strain rate was not different (P > .05) between step frequencies within each foot strike condition. Our results suggest that a rearfoot pattern may reduce AT stress, strain, and strain rate. Increases in step frequency of 5% above preferred frequency, regardless of foot strike pattern, may also lower peak AT stress and strain.

Effect of low velocity impact damage on the natural frequency of composite plates

Science.gov (United States)

Chok, E. Y. L.; Majid, D. L. A. A.; Harmin, M. Y.

2017-12-01

Biodegradable natural fibers have been suggested to replace the hazardous synthetic fibers in many aerospace applications. However, this notion has been limited due to their low mechanical properties, which leads to the idea of hybridizing the two materials. Many aircraft components such as radome, aft body and wing are highly susceptible to low velocity impact damage while in-service. The damages degrade the structural integrity of the components and change their dynamic characteristics. In worst case scenario, the changes can lead to resonance, which is an excessive vibration. This research is conducted to study the dynamic characteristic changes of low velocity impact damaged hybrid composites that is designed for aircraft radome applications. Three materials, which are glass fiber, kenaf fiber and kenaf/glass fiber hybrid composites, have been impacted with 3J, 6J and 9J of energy. Cantilevered and also vertically clamped boundary conditions are used and the natural frequencies are extracted for each of the specimens. The obtained results show that natural frequency decreases with increasing impact level. Cantilevered condition is found to induce lower modes due to the gravitational pull. To eliminate mass and geometrical effects, normalized modes are computed. Among the three materials considered, glass fiber composites have displayed the highest normalized frequency that reflects on its higher stiffness compared to the other two materials. As the damage level is increased, glass fiber composites have shown the highest frequency reduction to a maximum of 35% while kenaf composites have the least frequency reduction in the range of 1 - 18%. Thus, kenaf fiber is taken to be helpful in stalling the damage progression and reducing the effect of damage. This has been proven when the percentage frequency decrement shown by kenaf/glass fiber composite lies between glass fiber and kenaf fiber composites.

The Effect of Step Frequency Training on a Male Runner with Patellofemoral Pain

Directory of Open Access Journals (Sweden)

Shelley Payne

2016-10-01

Full Text Available Running is a very popular form of exercise. The most common site of injury for runners is the knee with patellofemoral pain being the most common complaint. Patellofemoral pain is described as pain around the patella that is worse with activities such as running, squatting, ascending or descending stairs, or sitting for long periods. Much of the recent work with the treatment of patellofemoral pain has involved strengthening of the hip musculature to reduce pain about the knee. However, the ability of these strengthening programs to change lower extremity mechanics or sustain long-term pain reduction has been unproven. More recently, researchers have started to examine the impact of step frequency modification on the forces encountered in the lower extremity, and specifically about the patellofemoral joint. The purpose of this study was to examine the short term effects of step frequency training in a recreational runner with PFP. Methods: This was a single-subject case study design. The subject completed a pre- and post-training assessment to determine the preferred step frequency. The subject also completed a Visual Analog Scale (VAS and a Lower Extremity Functional Scale (LEFS. Results: After the initial evaluation, the subject completed training 2 times per week for 4 weeks using auditory feedback to increase their step frequency by 5% above their preferred step frequency. The subject experienced a decrease in pain as measured by the VAS and an increase in function as measured by the LEFS across the 4 week training. Discussion: Although the results of this case study may not be generalized, the positive findings support additional research to determine both the short and long-term effects of step frequency training on PFP.

Frequency Specific Effects of ApoE ε4 Allele on Resting-State Networks in Nondemented Elders

Directory of Open Access Journals (Sweden)

Ying Liang

2017-01-01

Full Text Available We applied resting-state functional magnetic resonance imaging (fMRI to examine the Apolipoprotein E (ApoE ε4 allele effects on functional connectivity of the default mode network (DMN and the salience network (SN. Considering the frequency specific effects of functional connectivity, we decomposed the brain network time courses into two bands: 0.01–0.027 Hz and 0.027–0.08 Hz. All scans were acquired by the Alzheimer’s Disease Neuroscience Initiative (ADNI. Thirty-two nondemented subjects were divided into two groups based on the presence (n=16 or absence (n=16 of the ApoE ε4 allele. We explored the frequency specific effects of ApoE ε4 allele on the default mode network (DMN and the salience network (SN functional connectivity. Compared to ε4 noncarriers, the DMN functional connectivity of ε4 carriers was significantly decreased while the SN functional connectivity of ε4 carriers was significantly increased. Many functional connectivities showed significant differences at the lower frequency band of 0.01–0.027 Hz or the higher frequency band of 0.027–0.08 Hz instead of the typical range of 0.01–0.08 Hz. The results indicated a frequency dependent effect of resting-state signals when investigating RSNs functional connectivity.

Effect of irrigation frequencies on grain yield of maize

International Nuclear Information System (INIS)

Ahmad, M.; Chaudhry, M.H.; Amjed, M.T.

2008-01-01

To find out the water requirement and its application frequencies in spring Maize a trial was designed. The trial was comprised of five maize varieties (Ev-5098, EV-6098, EV-1098, Composite-20 and Pack Afgoyee) and five irrigation frequencies (7,8,9,10 and 11). The trial was sown in split plot design with three replication, keeping varieties in main plots and irrigation frequencies in sub plots. The plot size was 5m x 4.5 with 75cm apart rows and plant to plant distance was 15 com to maintain the 88888 plants per hectare. The trial was conducted during spring 2000 and 2001. Data were collected for days to 50% silking. Plant height (cm), cob height (cm) and grain yield per hectare. The data were analyzed and results obtained which revealed highly significant differences among varieties and also among irrigation frequencies in all the characters studied during both the years and in pooled analysis over years. The interaction between varieties and irrigation frequencies was highly significant for grain yield kg ha/sup -1/ and significant for other characters studied in year wise as well as in pooled analysis. Years effect was also high significant which is clear from the table of weather data which shows that temperature remained high during the crop season of 2001 as compared to 2000 along with high temperature more rains were also received in March. April and May in 2001 while in 2000 rain was received only in February. Three was gradual decrease in days to 50% silking with the increase in number of irrigations in all the varieties while plant height, cob height and grain yield increased with every addition of irrigation. Trend of increase or decrease remained the same during both the year. All the varieties separately or in combine showed better results during spring 2001, maximum grain yield was obtained by EV-5098 (full duration variety) with 11 irrigations during both the years 2000 and 2001 i.e. 3511 and 6140 kg ha/sup -1/ while EV-1098 (short duration variety

Study of the round edge disk hole's effects on the frequency and wakefield in disc structure

International Nuclear Information System (INIS)

Wang Lanfa; Hou Mi; Zhang Chuang

2001-01-01

The effects of the round edge beam hole on the frequency and wake field are studied using variational method, which allows for rounded iris disk hole without any approximation in shape treatment. The frequencies and wake fields of accelerating mode and dipole mode are studied for different edge radius cases, including the flat edge shape that is often used to approximately represent the actual structure geometry. The edge hole shape has weak effect on the frequency, but strong effect on the wakefield. The study shows that the amounts of wake fields are not precise enough with the assumption of the flat edge beam hole as of round edge. The shape assumption brings loss factor 15% err for the most dangerous EH 16 mode

An investigation the effects of geometric tolerances on the natural frequencies of rotating shafts

Directory of Open Access Journals (Sweden)

Ali Akbar Ansarifard

2015-04-01

Full Text Available This paper presents the effects of geometric tolerances on the rotating shafts natural frequencies. Due to modeling the tolerances, a code is written in MATLAB 2013 software that produces deviated points. Deviated points are controlled by different geometric tolerances, including cylindricity, total run-out and coaxiality tolerances. Final surfaces and models passing through the points are created using SolidWorks 2013 software and finally modal analysis is carried out with the FE software. It is observed whatever the natural frequency is higher or the geometric tolerances are greater, the real and ideal shafts natural frequencies are more distant. Also difference percentage between ideal and real frequencies is investigated. The results show that the percentage value is approximately constant for every mode shapes.

Effect of planecta and ROSE™ on the frequency characteristics of blood pressure-transducer kits.

Science.gov (United States)

Fujiwara, Shigeki; Kawakubo, Yoshifumi; Mori, Satoshi; Tachihara, Keiichi; Toyoguchi, Izumi; Yokoyama, Takeshi

2015-12-01

Pressure-transducer kits have frequency characteristics such as natural frequency and damping coefficient, which affect the monitoring accuracy. The aim of the present study was to investigate the effect of planecta ports and a damping device (ROSE™, Argon Medical Devices, TX, USA) on the frequency characteristics of pressure-transducer kits. The FloTrac sensor kit (Edwards Lifesciences, CA, USA) and the DTXplus transducer kit (Argon Medical Devices) were prepared with planecta ports, and their frequency characteristics were tested with or without ROSE™. The natural frequency and damping coefficient of each kit were obtained using frequency characteristics analysis software and evaluated by plotting them on the Gardner's chart. By inserting a planecta port, the natural frequency markedly decreased in both the FloTrac sensor kit (from 40 to 22 Hz) and the DTXplus transducer kit (from 35 to 22 Hz). In both kits with one planecta port, the damping coefficient markedly increased by insertion of ROSE™ from 0.2 to 0.5, optimising frequency characteristics. In both kits with two planecta ports, however, the natural frequency decreased from 22 to 12 Hz. The damping coefficient increased from 0.2 to 0.8 by insertion of ROSE™; however, optimisation was not achieved even by ROSE™ insertion. Planecta ports decrease the natural frequency of the kit. ROSE™ is useful to optimise the frequency characteristics in the kits without or with one planecta port. However, optimisation is difficult with two or more planecta ports, even with the ROSE™ device.

The effect of frequency and environment on the fatigue crack growth behaviour of SA508 Cl.III RPV steel

International Nuclear Information System (INIS)

Achilles, R.D.; Bulloch, J.H.

1987-01-01

This paper describes the effect of frequency and environment on the fatigue crack growth behaviour of SA508 Cl. III RPV steel. The study has shown that the effect of the Pressurised Water Reactor (PWR) environment is directly related to the frequency and the level of applied stress intensity of the test; these results further showed that the lower the frequency the greater the environmental effect, especially at low ΔK levels. No such frequency effect was observed in either the laboratory air or ultra-high purity argon environments. At a frequency of 0.1 Hz the PWR water test exhibited characteristic EAC growth, i.e. plateau growth behaviour. Fractographical examination of the fracture surface revealed that the fracture mode during plateau growth was intergranular failure. The experimental results are described and discussed in terms of the hydrogen assisted cracking mechanism. (author)

Effect of Temperature Variation on Modal Frequency of Reinforced Concrete Slab and Beam in Cold Regions

Directory of Open Access Journals (Sweden)

Hanbing Liu

2016-01-01

Full Text Available Changes of modal frequencies induced by temperature variation can be more obvious than those caused by structural damage, which will lead to the false damage identification results. Therefore, quantifying the temperature effect on modal frequencies is a critical step to eliminate its interference in damage detection. Due to the nonuniform and time-dependent characteristics of temperature distribution, it is insufficient to obtain the reliable relationships between temperatures and modal frequencies using temperatures in air or at surface. In this paper, correlations between measured temperatures (air temperature, surface temperature, mean temperature, etc. and modal frequencies for the slab and beam are comparatively analyzed. And the quantitative models are constructed considering nonuniform temperature distribution. Firstly, the reinforced concrete slab and beam were constructed and placed outside the laboratory to be monitored. Secondly, the correlation coefficients between modal frequencies and three kinds of temperatures are calculated, respectively. Thirdly, simple linear regression models between mean temperature and modal frequencies are established for the slab and beam. Finally, five temperature variables are selected to construct the multiple linear regression models. Prediction results reveal that the proposed multiple linear regression models possess favorable accuracy to quantify the temperature effect on modal frequencies considering nonuniform temperature distribution.

The Influence of Phonological Mechanisms in Written Spelling of Profoundly Deaf Children

Science.gov (United States)

Colombo, Lucia; Arfe, Barbara; Bronte, Tiziana

2012-01-01

In the present study, the effect of phonological and working memory mechanisms involved in spelling Italian single words was explored in two groups of children matched for grade level: a group of normally hearing children and a group of pre-verbally deaf children, with severe-to-profound hearing loss. Three-syllable and four-syllable familiar…

Frequency and effective treatment of ulcers and sinuses in cases of tuberculous cervical lymphadenitis

International Nuclear Information System (INIS)

Baskota, D.K.; Parasad, R.; Sinha, B.K.; Amatya, R.C.M.

2005-01-01

Objective: To investigate the frequency and effective treatment of ulcers and sinuses in cases of tuberculous cervical lymphadenitis (TCL). Patients and Methods: A hundred cases of histopathologically confirmed cases of tuberculous cervical lymphadenitis of more than six weeks of duration were included in the study. Overall frequency of the complication as well as the efficacy of treatment regime was considered. Results: Out of 100 patients, 8 (8%) were found to develop ulcers and/or sinuses during the process of development of TCL which were effectively treated (100% cure rate). Mode of treatment was surgical excision of ulcers/sinuses along with affected underlying lymph nodes, followed by short course of anti-tubercular chemotherapy. Not a single case recurred during their follow-up period. Conclusion: In this series there was a low frequency of formation of ulcers/sinuses during the process of development of TCL. Surgical excision of ulcers/sinuses along with affected underlying lymph nodes, followed by short course of anti-tubercular chemotherapy is the effective methods of their treatment. (author)

Black-body radiation effects and light shifts in atomic frequency standards

Energy Technology Data Exchange (ETDEWEB)

Pal' chikov, V G; Domnin, Yu S; Novoselov, A V [Institute of Metrology for Time and Space at National Research Institute for Physical-Technical and Radiotechnical Measurements - IMVP GP VNIIFTRI, Mendeleevo, Moscow Region, 141570 (Russian Federation)

2003-04-01

A general method is presented for calculating the higher-order terms of series in powers of the black-body radiation field for the Stark-state wavefunctions, dipole transition matrix elements and corresponding frequency shifts of hyperfine splitting in the ground states for Cs and Rb atoms. A numerical method for calculating the light shifts in Sr atoms is described. It is based on the Green function method for summation over all intermediate states and exact Dirac-Fock wavefunctions for the resonant transitions to the first excited s-, p- and d-states. By comparing the calculated Stark shift with results of measurements employing atomic frequency standards, the black-body radiation effects on the ground state are analysed.

Analysis and Correction of Diffraction Effect on the B/A Measurement at High Frequencies

Science.gov (United States)

Zhang, Dong; Gong, Xiu-Fen; Liu, Xiao-Zhou; Kushibiki, Jun-ichi; Nishino, Hideo

2004-01-01

A numerical method is developed to analyse and to correct the diffraction effect in the measurement of acoustic nonlinearity parameter B/A at high frequencies. By using the KZK nonlinear equation and the superposition approach of Gaussian beams, an analytical model is derived to describe the second harmonic generation through multi-layer medium SiO2/liquid specimen/SiO2. Frequency dependence of the nonlinear characterization curve for water in 110-155 MHz is numerically and experimentally investigated. With the measured dip position and the new model, values of B/A for water are evaluated. The results show that the present method can effectively correct the diffraction effect in the measurement.

Locus of word frequency effects in spelling to dictation: Still at the orthographic level!

Science.gov (United States)

Bonin, Patrick; Laroche, Betty; Perret, Cyril

2016-11-01

The present study was aimed at testing the locus of word frequency effects in spelling to dictation: Are they located at the level of spoken word recognition (Chua & Rickard Liow, 2014) or at the level of the orthographic output lexicon (Delattre, Bonin, & Barry, 2006)? Words that varied on objective word frequency and on phonological neighborhood density were orally presented to adults who had to write them down. Following the additive factors logic (Sternberg, 1969, 2001), if word frequency in spelling to dictation influences a processing level, that is, the orthographic output level, different from that influenced by phonological neighborhood density, that is, spoken word recognition, the impact of the 2 factors should be additive. In contrast, their influence should be overadditive if they act at the same processing level in spelling to dictation, namely the spoken word recognition level. We found that both factors had a reliable influence on the spelling latencies but did not interact. This finding is in line with an orthographic output locus hypothesis of word frequency effects in spelling to dictation. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Combined effects of extremely high frequency electromagnetic field and antibiotics on Enterococcus Hirae growth and survival

International Nuclear Information System (INIS)

Ohanyan, V.A.

2012-01-01

Combined effects of extremely high frequency electromagnetic field and antibiotics on Enterococcus hirae ATCC 9790 bacterial growth and survival were investigated using 51.8 GHz and 53 GHz frequencies in combination with two commonly used antibiotics: ampicillin and dalacin. Results revealed that, despite bacterial type and membrane structure and properties, the combined effect, especially with 53 GHz and dalacin, suppresses bacterial growth and decreases their survival

High-frequency effects in antiferromagnetic Sr3Ir2O7

Science.gov (United States)

Williamson, Morgan; Seinige, Heidi; Shen, Shida; Wang, Cheng; Cao, Gang; Zhou, Jianshi; Goodenough, John; Tsoi, Maxim

Antiferromagnetic (AFM) spintronics is one of many promising routes for `beyond the CMOS' technologies where unique properties of AFM materials are exploited to achieve new and improved functionalities. AFMs are especially interesting for high-speed memory applications thanks to their high natural frequencies. Here we report the effects of high-frequency (microwave) currents on transport properties of antiferromagnetic Mott insulator Sr3Ir2O7. The microwaves at 3-7 GHz were found to affect the material's current-voltage characteristic and produce resonance-like features that we tentatively associate with the dissipationless magnonics recently predicted to occur in antiferromagnetic insulators subject to ac electric fields. Our observations support the potential of antiferromagnetic materials for high-speed/high-frequency spintronic applications. This work was supported in part by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA, by NSF Grants DMR-1207577, DMR-1265162, DMR-1600057, and DMR-1122603, and by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. OSR-2015-CRG4-2626.

F0, voice quality, and Danish stød revisited

DEFF Research Database (Denmark)

Grønnum, Nina

2015-01-01

Danish stød is a syllable prosody, hitherto described as a kind of creaky voice with tonal side effects. One such is the well established, though not ubiquitous, abrupt lowering of F0 towards the end of the syllable. Eli Fischer-Jørgensen found, in the 1970s and 1980s, a difference also in the be...

Effect of low frequency noise on the evolution of the emittance and halo population

CERN Document Server

Fitterer, Miriam; Antoniou, Fanouria; Bravin, Enrico; Bruce, Roderik; Fartoukh, Stephane; Fuchsberger, Kajetan; Hofle, Wolfgang; Gasior, Marek; Jaussi, Michael; Jacquet, Delphine; Kotzian, Gerd; Olexa, Jakub; Papadopoulou, Parthena Stefania; Papotti, Giulia; Papaphilippou, Yannis; Redaelli, Stefano; Salvachua Ferrando, Belen Maria; Stancari, Giulio; Trad, Georges; Valuch, Daniel; Valentino, Gianluca; Wagner, Joschka; Wenninger, Jorg; CERN. Geneva. ATS Department

2016-01-01

For the High Luminosity upgrade the β* in IR1 and IR5 will be further reduced compared to the current LHC. As the β* decreases the β-functions in the inner triplet (IT) increase resulting in a higher sensitivity of the HL-LHC to ground motion in the IT region or to increases of the low frequency noise. Noise can in general lead to emittance growth and higher halo population and diffusion rate. However, it is usually assumed in the literature that only frequencies close to the betatron frequencies and sidebands have an effect on the emittance and tail population. To test this theory, an MD was carried out to observe if also low frequency noise can lead to emittance growth and stronger halo population and diffusion.

Effects of chirping on the dissociation dynamics of H2 in a two-frequency laser field

International Nuclear Information System (INIS)

Datta, Avijit; Bhattacharyya, S.S.; Kim, Bongsoo

2002-01-01

We present the effects of frequency chirping of laser pulses on (1+1)-photon resonance-enhanced dissociation dynamics of H 2 . The dissociation occurs via two closely spaced nonadiabatically coupled intermediate levels which are in one-photon resonance or near resonance with the initial level. Predissociating levels embedded into continua are considered. When the first laser field is sufficiently intense and suitably chirped, the dissociation probability is enhanced by adiabatic rapid passage through the avoided crossing arising from the frequency swept radiative interaction. The whole population of the ground level can be effectively transferred to the intermediate levels by this technique facilitating the dissociation process by the second field. We also report the effect of frequency detuning and chirp width on the dissociation probability. Widths of the two peaks of the dissociation line shape increase with an increase in chirp width, resulting in the possibility of control in the dissociation yield. When the first field is a laser pulse of low intensity and constant frequency and the second laser frequency is chirped, predissociating levels take important parts in the dissociation dynamics and we obtain a signature of the nonadiabatic effect of the first step on the second step of photodissociation dynamics. This feature is due to the presence of the predissociating levels and the nonadiabatic mixing of two intermediate levels. All these results can be explained in terms of the adiabatic dressed levels

The observed human sperm mutation frequency cannot explain the achondroplasia paternal age effect

Science.gov (United States)

Tiemann-Boege, Irene; Navidi, William; Grewal, Raji; Cohn, Dan; Eskenazi, Brenda; Wyrobek, Andrew J.; Arnheim, Norman

2002-01-01

The lifelong spermatogonial stem cell divisions unique to male germ cell production are thought to contribute to a higher mutation frequency in males. The fact that certain de novo human genetic conditions (e.g., achondroplasia) increase in incidence with the age of the father is consistent with this idea. Although it is assumed that the paternal age effect is the result of an increasing frequency of mutant sperm as a man grows older, no direct molecular measurement of the germ-line mutation frequency has been made to confirm this hypothesis. Using sperm DNA from donors of different ages, we determined the frequency of the nucleotide substitution in the fibroblast growth factor receptor 3 (FGFR3) gene that causes achondroplasia. Surprisingly, the magnitude of the increase in mutation frequency with age appears insufficient to explain why older fathers have a greater chance of having a child with this condition. A number of alternatives may explain this discrepancy, including selection for sperm that carry the mutation or an age-dependent increase in premutagenic lesions that remain unrepaired in sperm and are inefficiently detected by the PCR assay. PMID:12397172

Effects of low-frequency magnetic field on grain boundary segregation in horizontal direct chill casting of 2024 aluminum alloy

Institute of Scientific and Technical Information of China (English)

无

2005-01-01

Effects of low frequency electromagnetic field on grain boundary segregation in horizontal direct chill (HDC)casting process was investigated experimentally. The grain boundary segregation and microstructures of the ingots,which manufactured by conventional HDC casting and low frequency electromagnetic HDC casting were compared.Results show that low frequency electromagnetic field significantly refines the microstructures and reduces grain boundary segregation. Decreasing electromagnetic frequency or increasing electromagnetic intensity has great effects in reducing grain boundary segregation. Meanwhile, the governing mechanisms were discussed.

Tunable optical frequency comb enabled scalable and cost-effective multiuser orthogonal frequency-division multiple access passive optical network with source-free optical network units.

Science.gov (United States)

Chen, Chen; Zhang, Chongfu; Liu, Deming; Qiu, Kun; Liu, Shuang

2012-10-01

We propose and experimentally demonstrate a multiuser orthogonal frequency-division multiple access passive optical network (OFDMA-PON) with source-free optical network units (ONUs), enabled by tunable optical frequency comb generation technology. By cascading a phase modulator (PM) and an intensity modulator and dynamically controlling the peak-to-peak voltage of a PM driven signal, a tunable optical frequency comb source can be generated. It is utilized to assist the configuration of a multiple source-free ONUs enhanced OFDMA-PON where simultaneous and interference-free multiuser upstream transmission over a single wavelength can be efficiently supported. The proposed multiuser OFDMA-PON is scalable and cost effective, and its feasibility is successfully verified by experiment.

Numeracy, frequency, and Bayesian reasoning

Directory of Open Access Journals (Sweden)

Gretchen B. Chapman

2009-02-01

Full Text Available Previous research has demonstrated that Bayesian reasoning performance is improved if uncertainty information is presented as natural frequencies rather than single-event probabilities. A questionnaire study of 342 college students replicated this effect but also found that the performance-boosting benefits of the natural frequency presentation occurred primarily for participants who scored high in numeracy. This finding suggests that even comprehension and manipulation of natural frequencies requires a certain threshold of numeracy abilities, and that the beneficial effects of natural frequency presentation may not be as general as previously believed.

Effect of ultrasound frequency on the Nakagami statistics of human liver tissues.

Directory of Open Access Journals (Sweden)

Po-Hsiang Tsui

Full Text Available The analysis of the backscattered statistics using the Nakagami parameter is an emerging ultrasound technique for assessing hepatic steatosis and fibrosis. Previous studies indicated that the echo amplitude distribution of a normal liver follows the Rayleigh distribution (the Nakagami parameter m is close to 1. However, using different frequencies may change the backscattered statistics of normal livers. This study explored the frequency dependence of the backscattered statistics in human livers and then discussed the sources of ultrasound scattering in the liver. A total of 30 healthy participants were enrolled to undergo a standard care ultrasound examination on the liver, which is a natural model containing diffuse and coherent scatterers. The liver of each volunteer was scanned from the right intercostal view to obtain image raw data at different central frequencies ranging from 2 to 3.5 MHz. Phantoms with diffuse scatterers only were also made to perform ultrasound scanning using the same protocol for comparisons with clinical data. The Nakagami parameter-frequency correlation was evaluated using Pearson correlation analysis. The median and interquartile range of the Nakagami parameter obtained from livers was 1.00 (0.98-1.05 for 2 MHz, 0.93 (0.89-0.98 for 2.3 MHz, 0.87 (0.84-0.92 for 2.5 MHz, 0.82 (0.77-0.88 for 3.3 MHz, and 0.81 (0.76-0.88 for 3.5 MHz. The Nakagami parameter decreased with the increasing central frequency (r = -0.67, p < 0.0001. However, the effect of ultrasound frequency on the statistical distribution of the backscattered envelopes was not found in the phantom results (r = -0.147, p = 0.0727. The current results demonstrated that the backscattered statistics of normal livers is frequency-dependent. Moreover, the coherent scatterers may be the primary factor to dominate the frequency dependence of the backscattered statistics in a liver.

Segmented frequency-domain fluorescence lifetime measurements: minimizing the effects of photobleaching within a multi-component system.

Science.gov (United States)

Marwani, Hadi M; Lowry, Mark; Keating, Patrick; Warner, Isiah M; Cook, Robert L

2007-11-01

This study introduces a newly developed frequency segmentation and recombination method for frequency-domain fluorescence lifetime measurements to address the effects of changing fractional contributions over time and minimize the effects of photobleaching within multi-component systems. Frequency segmentation and recombination experiments were evaluated using a two component system consisting of fluorescein and rhodamine B. Comparison of experimental data collected in traditional and segmented fashion with simulated data, generated using different changing fractional contributions, demonstrated the validity of the technique. Frequency segmentation and recombination was also applied to a more complex system consisting of pyrene with Suwannee River fulvic acid reference and was shown to improve recovered lifetimes and fractional intensity contributions. It was observed that photobleaching in both systems led to errors in recovered lifetimes which can complicate the interpretation of lifetime results. Results showed clear evidence that the frequency segmentation and recombination method reduced errors resulting from a changing fractional contribution in a multi-component system, and allowed photobleaching issues to be addressed by commercially available instrumentation.

AC Josephson effect without superconductivity, and other effects of radio frequency quantum nanoelectronics

Science.gov (United States)

Waintal, Xavier; Gaury, Benoit; Weston, Joseph

With single coherent electron sources and electronic interferometers now available in the lab, the time resolved dynamics of electrons can now be probed directly. I will discuss how a fast raise of voltage propagates inside an electronic interferometer and leads to an oscillating current of well controled frequency. This phenomena is the normal counterpart to the AC josephson effect. I will also briefly advertize our software for computing quantum transport properties, Kwant (http://kwant-project.org) and its time-dependent extension T-Kwant.

Contributions of contour frequency, amplitude, and luminance to the watercolor effect estimated by conjoint measurement.

Science.gov (United States)

Gerardin, Peggy; Devinck, Frédéric; Dojat, Michel; Knoblauch, Kenneth

2014-04-10

The watercolor effect is a long-range, assimilative, filling-in phenomenon induced by a pair of distant, wavy contours of different chromaticities. Here, we measured joint influences of the contour frequency and amplitude and the luminance of the interior contour on the strength of the effect. Contour pairs, each enclosing a circular region, were presented with two of the dimensions varying independently across trials (luminance/frequency, luminance/amplitude, frequency/amplitude) in a conjoint measurement paradigm (Luce & Tukey, 1964). In each trial, observers judged which of the stimuli evoked the strongest fill-in color. Control stimuli were identical except that the contours were intertwined and generated little filling-in. Perceptual scales were estimated by a maximum likelihood method (Ho, Landy, & Maloney, 2008). An additive model accounted for the joint contributions of any pair of dimensions. As shown previously using difference scaling (Devinck & Knoblauch, 2012), the strength increases with luminance of the interior contour. The strength of the phenomenon was nearly independent of the amplitude of modulation of the contour but increased with its frequency up to an asymptotic level. On average, the strength of the effect was similar along a given dimension regardless of the other dimension with which it was paired, demonstrating consistency of the underlying estimated perceptual scales.

Effectiveness of a prolonged incarceration and rehabilitation measure for high-frequency offenders

NARCIS (Netherlands)

Tollenaar, N.; van der Laan, A. M.; van der Heijden, P. G M

2014-01-01

Objectives: To estimate the incapacitation effect and the impact on post-release recidivism of a measure combining prolonged incarceration and rehabilitation, the ISD measure for high frequency offenders (HFOs) was compared to the standard practice of short-term imprisonment. Methods: We applied a

Statistical Learning, Syllable Processing, and Speech Production in Healthy Hearing and Hearing-Impaired Preschool Children: A Mismatch Negativity Study.

Science.gov (United States)

Studer-Eichenberger, Esther; Studer-Eichenberger, Felix; Koenig, Thomas

2016-01-01

The objectives of the present study were to investigate temporal/spectral sound-feature processing in preschool children (4 to 7 years old) with peripheral hearing loss compared with age-matched controls. The results verified the presence of statistical learning, which was diminished in children with hearing impairments (HIs), and elucidated possible perceptual mediators of speech production. Perception and production of the syllables /ba/, /da/, /ta/, and /na/ were recorded in 13 children with normal hearing and 13 children with HI. Perception was assessed physiologically through event-related potentials (ERPs) recorded by EEG in a multifeature mismatch negativity paradigm and behaviorally through a discrimination task. Temporal and spectral features of the ERPs during speech perception were analyzed, and speech production was quantitatively evaluated using speech motor maximum performance tasks. Proximal to stimulus onset, children with HI displayed a difference in map topography, indicating diminished statistical learning. In later ERP components, children with HI exhibited reduced amplitudes in the N2 and early parts of the late disciminative negativity components specifically, which are associated with temporal and spectral control mechanisms. Abnormalities of speech perception were only subtly reflected in speech production, as the lone difference found in speech production studies was a mild delay in regulating speech intensity. In addition to previously reported deficits of sound-feature discriminations, the present study results reflect diminished statistical learning in children with HI, which plays an early and important, but so far neglected, role in phonological processing. Furthermore, the lack of corresponding behavioral abnormalities in speech production implies that impaired perceptual capacities do not necessarily translate into productive deficits.

Effects of increased meal frequency on fat oxidation and perceived hunger.

Science.gov (United States)

Ohkawara, Kazunori; Cornier, Marc-Andre; Kohrt, Wendy M; Melanson, Edward L

2013-02-01

Consuming smaller, more frequent meals is often advocated as a means of controlling body weight, but studies demonstrating a mechanistic effect of this practice on factors associated with body weight regulation are lacking. The purpose of this study was to compare the effect of consuming three (3M) vs. six meals (6M) per day on 24-h fat oxidation and subjective ratings of hunger. Lean (body mass index meal frequency from three to six per day has no significant effect on 24-h fat oxidation, but may increase hunger and the desire to eat. Copyright © 2012 The Obesity Society.

Frequency and effective treatment of ulcers and sinuses in cases of tuberculous cervical lymphadenitis.

Science.gov (United States)

Baskota, Dharma Kanta; Prasad, Rakesh; Sinha, Bimal Kumar; Amatya, Ram Chhaya Man

2005-03-01

To investigate the frequency and effective treatment of ulcers and sinuses in cases of tuberculous cervical lymphadenitis (TCL). Observational cross-sectional study. Department of ENT, Head and Neck Surgery of Tribhuvan University Teaching Hospital (TUTH), Kathmandu, Nepal, during the period of two years from March, 2000 to February, 2002. A hundred cases of histopathologically confirmed cases of tuberculous cervical lymphadenitis of more than six weeks of duration were included in the study. Overall frequency of the complication as well as the efficacy of treatment regime was considered. Out of 100 patients, 8 (8%) were found to develop ulcers and/or sinuses during the process of development of TCL which were effectively treated (100% cure rate). Mode of treatment was surgical excision of ulcers/sinuses along with affected underlying lymph nodes, followed by short course of anti-tubercular chemotherapy. Not a single case recurred during their follow-up period. In this series there was a low frequency of formation of ulcers/sinuses during the process of development of TCL. Surgical excision of ulcers/sinuses along with affected underlying lymph nodes, followed by short course of anti-tubercular chemotherapy is the effective methods of their treatment.

Very-low-frequency magnetic plasma

International Nuclear Information System (INIS)

Pendry, J.B.; O'Brien, S.

2002-01-01

We show that a set of current-carrying wires can exhibit an effective magnetic permeability at very low frequencies of a few hertz. The resonant permeability, which is negative above the resonance frequency, arises from the oscillations of the wires driven by the applied magnetic field. We show that a large, frequency-specific and tunable effective permeability can be realized for a wide range of strengths of the applied field. (author)

Resonant effects on the low frequency vlasov stability of axisymmetric field reversed configurations

International Nuclear Information System (INIS)

Finn, J.M.; Sudan, R.N.

We investigate the effect of particle resonances on low frequency MHD modes in field-reversed geometries, e.g., an ion ring. It is shown that, for sufficiently high field reversal, modes which are hydromagnetically stable can be driven unstable by ion resonances. The stabilizing effect of a toroidal magnetic field is discussed

Primary phonological planning units in spoken word production are language-specific: Evidence from an ERP study.

Science.gov (United States)

Wang, Jie; Wong, Andus Wing-Kuen; Wang, Suiping; Chen, Hsuan-Chih

2017-07-19

It is widely acknowledged in Germanic languages that segments are the primary planning units at the phonological encoding stage of spoken word production. Mixed results, however, have been found in Chinese, and it is still unclear what roles syllables and segments play in planning Chinese spoken word production. In the current study, participants were asked to first prepare and later produce disyllabic Mandarin words upon picture prompts and a response cue while electroencephalogram (EEG) signals were recorded. Each two consecutive pictures implicitly formed a pair of prime and target, whose names shared the same word-initial atonal syllable or the same word-initial segments, or were unrelated in the control conditions. Only syllable repetition induced significant effects on event-related brain potentials (ERPs) after target onset: a widely distributed positivity in the 200- to 400-ms interval and an anterior positivity in the 400- to 600-ms interval. We interpret these to reflect syllable-size representations at the phonological encoding and phonetic encoding stages. Our results provide the first electrophysiological evidence for the distinct role of syllables in producing Mandarin spoken words, supporting a language specificity hypothesis about the primary phonological units in spoken word production.

Effect of High Frequency Pulsing on the Interfacial Structure of Anodised Aluminium-TiO2

DEFF Research Database (Denmark)

Gudla, Visweswara Chakravarthy; Jensen, Flemming; Bordo, Kirill

2015-01-01

High frequency anodizing of friction stir processed Al-TiO2 surface composites was investigated. The effect of anodizing parameters on the structure and morphology of the anodic layer including the incorporation of the TiO2 particles into the anodic layer is studied. Anodizing process was carried...... out using a high frequency pulse and pulse reverse pulse technique at a fixed frequency in a sulfuric acid bath. The structure of the composites and the anodized layer was studied using scanning and transmission electron microscopy. The pulse reverse pulse anodizing technique, using a negative...

Frequency shifting at fiber-optical event horizons: The effect of Raman deceleration

International Nuclear Information System (INIS)

Robertson, S.; Leonhardt, U.

2010-01-01

Pulses in fibers establish analogs of the event horizon [Philbin et al., Science 319, 1367 (2008)]. At a group-velocity horizon, the frequency of a probe wave is shifted. We present a theoretical model of this frequency shifting, taking into account the deceleration of the pulse caused by the Raman effect. The theory shows that the probe-wave spectrum is sensitive to details of the probe-pulse interaction. Our results indicate an additional loss mechanism in the experiment [Philbin et al., Science 319, 1367 (2008)] that has not been accounted for. Our analysis is also valid for more general cases of the interaction of dispersive waves with decelerated solitons.

Effects of cue frequency and repetition on prospective memory: an ERP investigation.

Science.gov (United States)

Wilson, Jennifer; Cutmore, Tim R H; Wang, Ya; Chan, Raymond C K; Shum, David H K

2013-11-01

Prospective memory involves the formation and completion of delayed intentions and is essential for independent living. In this study (n = 33), event-related potentials (ERPs) were used to systematically evaluate the effects of PM cue frequency (10% versus 30%) and PM cue repetition (high versus low) on ERP modulations. PM cues elicited prospective positivity and frontal positivity but not N300, perhaps due to the semantic nature of the task. Results of this study revealed an interesting interaction between PM cue frequency and PM cue repetition for prospective positivity and frontal positivity, highlighting the importance of taking both factors into account when designing future studies. © 2013.

Interactions between amplitude modulation and frequency modulation processing: Effects of age and hearing loss.

Science.gov (United States)

Paraouty, Nihaad; Ewert, Stephan D; Wallaert, Nicolas; Lorenzi, Christian

2016-07-01

Frequency modulation (FM) and amplitude modulation (AM) detection thresholds were measured for a 500-Hz carrier frequency and a 5-Hz modulation rate. For AM detection, FM at the same rate as the AM was superimposed with varying FM depth. For FM detection, AM at the same rate was superimposed with varying AM depth. The target stimuli always contained both amplitude and frequency modulations, while the standard stimuli only contained the interfering modulation. Young and older normal-hearing listeners, as well as older listeners with mild-to-moderate sensorineural hearing loss were tested. For all groups, AM and FM detection thresholds were degraded in the presence of the interfering modulation. AM detection with and without interfering FM was hardly affected by either age or hearing loss. While aging had an overall detrimental effect on FM detection with and without interfering AM, there was a trend that hearing loss further impaired FM detection in the presence of AM. Several models using optimal combination of temporal-envelope cues at the outputs of off-frequency filters were tested. The interfering effects could only be predicted for hearing-impaired listeners. This indirectly supports the idea that, in addition to envelope cues resulting from FM-to-AM conversion, normal-hearing listeners use temporal fine-structure cues for FM detection.

Effects of high fire frequency in creosote bush scrub vegetation of the Mojave Desert

Science.gov (United States)

Brooks, M.L.

2012-01-01

Plant invasions can increase fire frequency in desert ecosystems where fires were historically infrequent. Although there are many resource management concerns associated with high frequency fire in deserts, fundamental effects on plant community characteristics remain largely unstudied. Here I describe the effects of fire frequency on creosote bush scrub vegetation in the Mojave Desert, USA. Biomass of the invasive annual grass Bromus rubens L. increased following fire, but did not increase further with additional fires. In contrast, density, cover and species richness of native perennial plants each decreased following fire and continued to decrease with subsequent fires, although not as dramatically as after the initial fire. Responses were similar 5 and 14 years post-fire, except that cover of Hymenoclea salsola Torr. & A. Gray and Achnatherum speciosa Trin. & Rupr. both increased in areas burnt once. These results suggest that control of B. rubens may be equally warranted after one, two or three fires, but revegetation of native perennial plants is most warranted following multiple fires. These results are valid within the scope of this study, which is defined as relatively short term vegetation responses (???14 years) to short fire return intervals (6.3 and 7.3 years for the two and three fire frequency levels) within creosote bush scrub of the Mojave Desert. ?? 2012 IAWF.

Nonlinear Filtering Effects of Reservoirs on Flood Frequency Curves at the Regional Scale: RESERVOIRS FILTER FLOOD FREQUENCY CURVES

Energy Technology Data Exchange (ETDEWEB)

Wang, Wei; Li, Hong-Yi; Leung, Lai-Yung; Yigzaw, Wondmagegn Y.; Zhao, Jianshi; Lu, Hui; Deng, Zhiqun; Demissie, Yonas; Bloschl, Gunter

2017-10-01

Anthropogenic activities, e.g., reservoir operation, may alter the characteristics of Flood Frequency Curve (FFC) and challenge the basic assumption of stationarity used in flood frequency analysis. This paper presents a combined data-modeling analysis of the nonlinear filtering effects of reservoirs on the FFCs over the contiguous United States. A dimensionless Reservoir Impact Index (RII), defined as the total upstream reservoir storage capacity normalized by the annual streamflow volume, is used to quantify reservoir regulation effects. Analyses are performed for 388 river stations with an average record length of 50 years. The first two moments of the FFC, mean annual maximum flood (MAF) and coefficient of variations (CV), are calculated for the pre- and post-dam periods and compared to elucidate the reservoir regulation effects as a function of RII. It is found that MAF generally decreases with increasing RII but stabilizes when RII exceeds a threshold value, and CV increases with RII until a threshold value beyond which CV decreases with RII. The processes underlying the nonlinear threshold behavior of MAF and CV are investigated using three reservoir models with different levels of complexity. All models capture the non-linear relationships of MAF and CV with RII, suggesting that the basic flood control function of reservoirs is key to the non-linear relationships. The relative roles of reservoir storage capacity, operation objectives, available storage prior to a flood event, and reservoir inflow pattern are systematically investigated. Our findings may help improve flood-risk assessment and mitigation in regulated river systems at the regional scale.

Research surface resistance of copper normal and abnormal skin-effects depending on the frequency of electromagnetic field

International Nuclear Information System (INIS)

Kutovyi, V.A.; Komir, A.I.

2013-01-01

The results of the frequency dependence of surface resistance of copper in diffuse and specular reflection of electrons from the conductive surface of the high-frequency resonance of the system depending on the frequency of the electromagnetic field in the normal and anomalous skin effect. Found, the surface resistance of copper is reduced by more than 10 times at the temperature of liquid helium, as compared with a surface resistivity at room temperature, at frequencies f ≤ 173 MHz, for diffuse reflection of conduction electrons from the surface of the conductive layer, and the specular reflection - at frequencies f ≤ 346 MHz

Effects of switching frequency and leakage inductance on slow-scale stability in a voltage controlled flyback converter

International Nuclear Information System (INIS)

Wang Fa-Qiang; Ma Xi-Kui

2013-01-01

The effects of both the switching frequency and the leakage inductance on the slow-scale stability in a voltage controlled flyback converter are investigated in this paper. Firstly, the system description and its mathematical model are presented. Then, the improved averaged model, which covers both the switching frequency and the leakage inductance, is established, and the effects of these two parameters on the slow-scale stability in the system are analyzed. It is found that the occurrence of Hopf bifurcation in the system is the main reason for losing its slow-scale stability and both the switching frequency and the leakage inductance have an important effect on this slow-scale stability. Finally, the effectiveness of the improved averaged model and that of the corresponding theoretical analysis are confirmed by the simulation results and the experimental results. (general)

Effect of photonic crystal and frequency selective surface implementation on gain enhancement in the microstrip patch antenna at terahertz frequency

Energy Technology Data Exchange (ETDEWEB)

Nejati, Ameneh, E-mail: ameneh.nejati@gmail.com [Department of Electrical Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Sadeghzadeh, Ramezan Ali [Faculty of Electrical and Computer Engineering, K.N Toosi University of Technology, Tehran (Iran, Islamic Republic of); Geran, Fatemeh [Faculty of Electrical and Computer Engineering, Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of)

2014-09-15

In this paper, microstrip patch antenna with frequency selective surface (FSS) and photonic band gap (PBG) structures in the frequency range of 0.5–0.7 THz is presented for wireless communications. Proposed patch antenna is designed on a substrate with uniform and non-uniform PBG structures. Here, the effects of substrate thickness, various radii and arrangement of holes on antenna resonance in both PBG forms are studied. Near zero characteristic on uniform and non-uniform PBG substrate is compared and the results show that along with increase in hole radius, antenna operating frequency and bandwidth are increased. Also, the FSS structure is designed as a perfect absorber. Finally, by using FSS and PBG structures simultaneously, gain enhancement, increase in directivity and pattern shaping are studied at THz field. The antenna gain in final structure is increased by 2 dBi (32%) in comparison to simple form and Half-Power beam width is reduced from 100°×80° in simple form to 72°×48° by using FSS and PBG. All simulations and designs are done by Ansoft HFSS and CST Microwave Studio simulation tools with different full wave methods.

Effect of low-frequency low-intensity ultrasound with microbubbles on prostate cancer hypoxia.

Science.gov (United States)

Hou, Rui; Xu, Yanjun; Lu, Qijie; Zhang, Yang; Hu, Bing

2017-10-01

Angiogenesis plays an important role in tumor growth, invasiveness, and metastasis. It is well established that prostate cancer is exposed to fluctuating oxygen tensions and both acute and chronic hypoxia exist, and these conditions can upregulate angiogenesis-associated proteins such as hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A. Low-frequency low-intensity ultrasound with microbubbles can induce obvious microvessel damage in tumors, cause cell necrosis or apoptosis. However, there is no information about whether the blocking blood effect of low-frequency low-intensity ultrasound with microbubbles has an influence on hypoxia environment of prostate cancer. Therefore, we investigated the impact of different low-frequency low-intensity ultrasound with microbubbles radiation times on prostate tumors, observed the change in the hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A protein levels, as well as cell proliferation, apoptosis, and tumor volume. The results indicated that as the radiation was repeated four times on each treatment day, the effects of interruption were durable, the cell proliferation was inhibited, and apoptosis was promoted, and the hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A expression levels were lower in the treatment group than in the control group. When the radiation was carried out once per treatment day, the hypoxia response was stimulated, the hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A expression levels were higher compared with the control group, and cell proliferation was promoted. In addition, the tumor volume increased obviously in the hypoxia-stimulated group, whereas tumors grew slowly in the hypoxia-suppressed group. The results of this work demonstrated that under the same conditions, different radiation times of low-frequency low-intensity ultrasound with microbubbles affect the hypoxia response differently, and the

Atmospheric and Fog Effects on Ultra-Wide Band Radar Operating at Extremely High Frequencies.

Science.gov (United States)

Balal, Nezah; Pinhasi, Gad A; Pinhasi, Yosef

2016-05-23

The wide band at extremely high frequencies (EHF) above 30 GHz is applicable for high resolution directive radars, resolving the lack of free frequency bands within the lower part of the electromagnetic spectrum. Utilization of ultra-wideband signals in this EHF band is of interest, since it covers a relatively large spectrum, which is free of users, resulting in better resolution in both the longitudinal and transverse dimensions. Noting that frequencies in the millimeter band are subjected to high atmospheric attenuation and dispersion effects, a study of the degradation in the accuracy and resolution is presented. The fact that solid-state millimeter and sub-millimeter radiation sources are producing low power, the method of continuous-wave wideband frequency modulation becomes the natural technique for remote sensing and detection. Millimeter wave radars are used as complementary sensors for the detection of small radar cross-section objects under bad weather conditions, when small objects cannot be seen by optical cameras and infrared detectors. Theoretical analysis for the propagation of a wide "chirped" Frequency-Modulated Continuous-Wave (FMCW) radar signal in a dielectric medium is presented. It is shown that the frequency-dependent (complex) refractivity of the atmospheric medium causes distortions in the phase of the reflected signal, introducing noticeable errors in the longitudinal distance estimations, and at some frequencies may also degrade the resolution.

Biological and clinical effects of low-frequency magnetic and electric fields

Energy Technology Data Exchange (ETDEWEB)

Llaurado, J.G.; Sances, A. Jr.; Battocletti, J. (eds.)

1974-01-01

The blurb on this book states that it has been written for physicians, biologists, psychologists, engineers and those persons interested in the interaction of low frequency electric and magnetic fields upon animals and man. Certainly, the content of this book--which comprises papers presented by specialists at a symposium on The Effects of Low Frequency Magnetic Fields on Biological Communication Processes held in Aspen, Colorado--does not make simple reading and those lacking the necessary background are unlikely to make much progress. This said, however, the book can be recommended to those with the necessary interest, knowledge and perseverance. The book provides a great deal of information in a convenient manner and all those concerned with its production are to be congratulated on their work. Articles are well set out, illustrated and supported by abstracts, extensive references and discussions. As indicated above, the range of the subjects covered is large and includes such varied items as acupuncture, bird communication and some details of the U.S.A. Navy's extra low frequency communication system known as Project Sanguine. Finally, it is a pleasure to say that the book has been attractively produced and contains an excellent index.

Effects of meal frequency on weight loss and body composition: a meta-analysis.

Science.gov (United States)

Schoenfeld, Brad Jon; Aragon, Alan Albert; Krieger, James W

2015-02-01

It has been hypothesized that eating small, frequent meals enhances fat loss and helps to achieve better weight maintenance. Several observational studies lend support to this hypothesis, with an inverse relationship noted between the frequency of eating and adiposity. The purpose of this narrative review is to present and discuss a meta-analysis with regression that evaluated experimental research on meal frequency with respect to changes in fat mass and lean mass. A total of 15 studies were identified that investigated meal frequency in accordance with the criteria outlined. Feeding frequency was positively associated with reductions in fat mass and body fat percentage as well as an increase in fat-free mass. However, sensitivity analysis of the data showed that the positive findings were the product of a single study, casting doubt as to whether more frequent meals confer beneficial effects on body composition. In conclusion, although the initial results of this meta-analysis suggest a potential benefit of increased feeding frequencies for enhancing body composition, these findings need to be interpreted with circumspection. © The Author(s) 2015. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

The Effect of High Frequency Pulse on the Discharge Probability in Micro EDM

Science.gov (United States)

Liu, Y.; Qu, Y.; Zhang, W.; Ma, F.; Sha, Z.; Wang, Y.; Rolfe, B.; Zhang, S.

2017-12-01

High frequency pulse improves the machining efficiency of micro electric discharge machining (micro EDM), while it also brings some changes in micro EDM process. This paper focuses on the influence of skin-effect under the high frequency pulse on energy distribution and transmission in micro EDM, based on which, the rules of discharge probability of electrode end face are also analysed. On the basis of the electrical discharge process under the condition of high frequency pulse in micro EDM, COMSOL Multiphysics software is used to establish energy transmission model in micro electrode. The discharge energy distribution and transmission within tool electrode under different pulse frequencies, electrical currents, and permeability situation are studied in order to get the distribution pattern of current density and electric field intensity in the electrode end face under the influence of electrical parameters change. The electric field intensity distribution is regarded as the influencing parameter of discharge probability on the electrode end. Finally, MATLAB is used to fit the curve and obtain the distribution of discharge probability of electrode end face.

ESCOLEX: a grade-level lexical database from European Portuguese elementary to middle school textbooks.

Science.gov (United States)

Soares, Ana Paula; Medeiros, José Carlos; Simões, Alberto; Machado, João; Costa, Ana; Iriarte, Álvaro; de Almeida, José João; Pinheiro, Ana P; Comesaña, Montserrat

2014-03-01

In this article, we introduce ESCOLEX, the first European Portuguese children's lexical database with grade-level-adjusted word frequency statistics. Computed from a 3.2-million-word corpus, ESCOLEX provides 48,381 word forms extracted from 171 elementary and middle school textbooks for 6- to 11-year-old children attending the first six grades in the Portuguese educational system. Like other children's grade-level databases (e.g., Carroll, Davies, & Richman, 1971; Corral, Ferrero, & Goikoetxea, Behavior Research Methods, 41, 1009-1017, 2009; Lété, Sprenger-Charolles, & Colé, Behavior Research Methods, Instruments, & Computers, 36, 156-166, 2004; Zeno, Ivens, Millard, Duvvuri, 1995), ESCOLEX provides four frequency indices for each grade: overall word frequency (F), index of dispersion across the selected textbooks (D), estimated frequency per million words (U), and standard frequency index (SFI). It also provides a new measure, contextual diversity (CD). In addition, the number of letters in the word and its part(s) of speech, number of syllables, syllable structure, and adult frequencies taken from P-PAL (a European Portuguese corpus-based lexical database; Soares, Comesaña, Iriarte, Almeida, Simões, Costa, …, Machado, 2010; Soares, Iriarte, Almeida, Simões, Costa, França, …, Comesaña, in press) are provided. ESCOLEX will be a useful tool both for researchers interested in language processing and development and for professionals in need of verbal materials adjusted to children's developmental stages. ESCOLEX can be downloaded along with this article or from http://p-pal.di.uminho.pt/about/databases .

The effect of sampling rate and anti-aliasing filters on high-frequency response spectra

Science.gov (United States)

Boore, David M.; Goulet, Christine

2013-01-01

The most commonly used intensity measure in ground-motion prediction equations is the pseudo-absolute response spectral acceleration (PSA), for response periods from 0.01 to 10 s (or frequencies from 0.1 to 100 Hz). PSAs are often derived from recorded ground motions, and these motions are usually filtered to remove high and low frequencies before the PSAs are computed. In this article we are only concerned with the removal of high frequencies. In modern digital recordings, this filtering corresponds at least to an anti-aliasing filter applied before conversion to digital values. Additional high-cut filtering is sometimes applied both to digital and to analog records to reduce high-frequency noise. Potential errors on the short-period (high-frequency) response spectral values are expected if the true ground motion has significant energy at frequencies above that of the anti-aliasing filter. This is especially important for areas where the instrumental sample rate and the associated anti-aliasing filter corner frequency (above which significant energy in the time series is removed) are low relative to the frequencies contained in the true ground motions. A ground-motion simulation study was conducted to investigate these effects and to develop guidance for defining the usable bandwidth for high-frequency PSA. The primary conclusion is that if the ratio of the maximum Fourier acceleration spectrum (FAS) to the FAS at a frequency fsaa corresponding to the start of the anti-aliasing filter is more than about 10, then PSA for frequencies above fsaa should be little affected by the recording process, because the ground-motion frequencies that control the response spectra will be less than fsaa . A second topic of this article concerns the resampling of the digital acceleration time series to a higher sample rate often used in the computation of short-period PSA. We confirm previous findings that sinc-function interpolation is preferred to the standard practice of using

Effect of frequency variation on electromagnetic pulse interaction with charges and plasma

NARCIS (Netherlands)

Khachatryan, A.G.; van Goor, F.A.; Verschuur, Jeroen W.J.; Boller, Klaus J.

2005-01-01

The effect of frequency variation (chirp) in an electromagnetic (EM) pulse on the pulse interaction with a charged particle and plasma is studied. Various types of chirp and pulse envelopes are considered. In vacuum, a charged particle receives a kick in the polarization direction after interaction