Location Of Constriction Research Articles

Location of constriction in velar sounds in French

This study examines the constriction location (CL) of the velar stop [k] in French. While previous studies have investigated how vocalic contexts influence the CL of velar stops [Liker & Gibbon (2008) Clin. Ling. & Phon. 22(2); Tabain (2000) JPhon 28(2)], few investigated high-level changes in CL. Building on our prior work [Islam & Gick (2023) JASA 154], which showed an unexpected palato-velar articulation of [k] followed by [a] compared with [w] followed by [a], we tested whether this [k]-palatalizing is universal or specific to [a]. Using a French MRI speech corpus [Isaieva et al., Scientific Data 8], we measured constriction in [k] before [i], [ɛ], [o], [u], and [a]. MRI video frames were manually traced to mark the upper surface of the tongue and the lower surface of the hard palate, resulting in two contours. Using Euclidean distance, the location of the constriction was identified as the narrowest point and distance, respectively, between the two contours. A Python script that measured Euclidean distance from traced MRI frames calculated these distances from the MRI frames. Results indicate a frontal shift in [k] across all contexts, indicating a general fronting articulation of [k] in French speech.

The [s -- > ʃ] sound change in /str-/ contexts: how temporal changes in the acoustic spectrum affect fricative percept

Studies have documented a sound change in some English dialects whereby /s/ in the context /strV/ surfaces as [ʃtrV]. This can be interpreted as /s/ rounding for the rhotic being re-analyzed as [ʃ]. We recently measured F;M, the frequency of the main peak in mid-fricative spectra, in seven adults producing words with /s/ and /ʃ/ across phonetic contexts and compared the acoustics to perceptual rankings on an [ʃ] to [s] scale. One speaker exhibited a perceived sound change; two, partial sound changes. It was shown that F;M was correlated with the perceptual rankings for /strV/ words. However, in all speakers, lowered F;M for /s/ in labial contexts did not affect percepts. The time course of lip rounding and tongue-tip retraction in /strV/ could help differentiate coarticulation versus a phonemic change. Interestingly, however, X-Ray Microbeam data [Iskarous, K. et al. (2011) Articulatory-acoustic kinematics of /s/, J. Acoust. Soc. Am. 129, 944-954] showed that / s/ constriction location was constant over time except in /str-/ context. This study will assess the amount and timing of F;M lowering, its perceptual consequences and likely articulatory causes, to gain more insight into the [strV] -- > [ʃtrV] sound change.

Dynamic blending and assimilation in Catalan lingual fricative sequences. An ultrasound and acoustic study

Abstract Ultrasound and center of gravity frequency data for the sequences /ʃ#s/ and /s#ʃ/ produced by Central Catalan speakers reveal that the former sequence is implemented through continuous articulatory and spectral trajectories which, depending on speaker, may be: intermediate between /ʃ/ and /s/ all throughout, thus supporting a dynamic blending mechanism; /ʃ/-like at onset and intermediate between the two fricatives at offset, which is indicative of C1-to-C2 carryover coarticulation. The sequence /s#ʃ/, on the other hand, undergoes regressive assimilation into [ʃ(ʃ)] according to the acoustic signal but less clearly so in the light of the articulatory data. This discrepancy appears to be due to the fact that, while C1=/s/ assimilates indeed to C2=/ʃ/ at constriction location, coarticulation-induced changes in tongue body configuration behind the primary articulator may occur as long as they do not jeopardize the front-cavity dependent frequency characteristics of the [ʃ] frication noise. Differences in articulatory complexity between /ʃ#s/ and /s#ʃ/ appear to result from the production mechanisms involved, i.e., tongue dorsum raising behind the /s/ constriction for /s#ʃ/ and tongue body repositioning for /ʃ#s/. In agreement with this interpretation, /ʃ#s/ but not /s#ʃ/ turned out to be longer than /s#s/ and /ʃ#ʃ/.

Solute translocation probability, lifetime, and "rectification" in membrane channels with localized constriction.

We study the translocation probability and lifetime of a solute molecule in a cylindrical membrane channel that contains a localized constriction at an arbitrary location. Using a one-dimensional continuous diffusion description of solute dynamics in the channel, we explore two models. The first one describes a molecule's interaction with the constriction in terms of a narrow rectangular barrier in the potential of mean force. The second novel model proposed here represents this interaction by introducing an infinitely thin permeable partition. It is shown that when the parameters of the two models are chosen to warrant the same translocation probability, both models predict the same mean lifetime of the molecule in the channel. While the translocation probability is independent of the constriction location, the mean lifetime is a function of the location. The benefit of the thin partition model is that it allows one to lump together the height and length of the potential barrier into a single parameter, which is the partition's permeability. It is shown that in the case of an asymmetric location of the localized constriction and strong repulsion between the solutes, the solute flux through the channel is a function of the direction in which it goes, analogous to the phenomenon known in ion channel electrophysiology as rectification.

An MRI-based articulatory analysis of the Kannada dental-retroflex contrast

AbstractThis paper investigates the production of dental and retroflex stops, fricatives, nasals, and laterals in the Dravidian language Kannada. This is done using articulatory contours extracted from an extensive midsagittal MRI corpus of two female Kannada speakers’ static vocal tract postures intended to capture key aspects of phonemic articulations. Articulatory modelling was used to determine a set of components responsible for the implementation of place and manner contrasts (/t̪ s̪ n̪ l̪/ vs. /ʈ ʂ ɳ ɭ/). These components included both lingual and non-lingual articulatory parameters. Constriction location and length were also determined based on articulatory contours. The results showed that the two speakers produced non-fricative retroflexes with a retracted tongue tip making a constriction behind the alveolar ridge and a characteristic convex tongue shape, yet without a retraction of the posterior portion of the tongue. Apart from the lingual parameters, place differences were also manifested by the vertical position of the larynx (lower for retroflexes). The realisation of the place contrast in sibilant fricatives was different, as /ʂ/ appeared to be produced by both speakers with a laminal alveolopalatal constriction. Manner differences were captured by various non-lingual parameters, yet being also manifested in constriction locations (more anterior for stops). These findings are discussed in the context of previous descriptive and articulatory accounts of dental-retroflex contrasts.

Location and size of constriction in labiovelar, velar, and uvular sounds in French

This study investigates the location and size of constriction in the labio-velar sound [w]. While there have been studies exploring constrictions in different sounds including schwa [Gick, 2002, Phonetica 59], /r/ [Epsy-Wilsonet al., 2000, JASA 108], and clicks [Miller et al., 2009, JIPA 39], the understanding of the constriction in labio-velar sound [w] in relation to neighboring sounds is limited. We utilized an MRI corpus of French speech [Isaieva et al., Scientific Data 8] to measure the location and size of the constrictions in [w], [k], [u], and [ʁ]. The MRI video frames were manually traced to mark the upper surface of the tongue and the lower surface of the hard-palate, velum, and uvula, resulting in two contours. Using Euclidean distance, the location and size of the constriction were identified as the narrowest point and distance, respectively, between the two contours. Results confirmed that [w,u] had constrictions against the velum; [k]’s, however, had constrictions fronter than [w,u] (centroids were 0.88au apart on normalized X-Y space), making them more palatal. [ʁ]’s had uvular constrictions, as expected. Regarding constriction size, [w], despite being an approximant consonant, had a more open constriction than the vowel [u].

Near-merger of /s: ʃ/ in Veneto Italian: A preliminary cross-generational acoustic investigation

Italian contrasts /s:/ and /ʃ/. Although in standard Italian (SI) the two phonemes have distinct places of articulation (laminal denti-alveolar and laminal post-alveolar, respectively), early descriptions of the Italian spoken in the Veneto (VI) report a near-merger due to the absence of /ʃ/ in the regional substratum dialect (Canepari 1984). Accordingly, /s:/ is retracted and aplicalized, and /ʃ/ is advanced and in some cases also apicalized in VI. To investigate this phenomenon, an acoustic and statistical analysis of spectral Center of Gravity (COG), known to increase with more advanced constriction location for coronals, is conducted on 192 /s:/ and /ʃ/ tokens produced by six VI speakers (three males and three females) of varying ages (34 to 68) producing eight repetitions of /ˈkassa kasˈsata ˈlaʃa laˈʃata/ ‘case, cassata cake, he/she/it leaves, left’ within carrier sentences. Results show that, regardless of sex, the two older speakers (50 and 68) but not the four younger speakers (34 to 44) produce statistically similar COG values for the two consonants, indicating similar constriction locations. This preliminary study suggests that the near-merger may be produced by older speakers but not younger speakers today, in an ongoing process of standardization of Italian pronunciation across regional varieties.

Retrospective computed tomography analysis of endotracheal tube constriction and mispositioning in cats and dogs

ObjectiveTo discover the prevalence of endotracheal tube (ETT) constriction and rostral and caudal mispositioning in anaesthetized cats and dogs, and to identify associated risk factors. Study designRetrospective analysis. AnimalsA total of 146 cats and 670 dogs. MethodsComputed tomography images of the head/neck/thorax from orotracheally intubated cats and dogs were visually assessed for constriction or mispositioning of the ETT. If constriction was present, measurements of the cross-sectional area (CSA) of the ETT lumen at constricted and un-constricted locations were compared. Location and cause of constriction were noted and the expected increase in resistance to gas flow was calculated. Animal information was collected from clinical records. Normality of continuous variables was assessed via the Shapiro–Wilk test. Chi-square tests examined associations between variables. Kendall’s tau-b test was performed between measured ETT size and degree of constriction. ResultsThe ETT extended rostrally beyond incisors in 52% of cases; the connector was within the oral cavity in 19% of cases. The ETT extended beyond the first rib in 25.5% of cases. The prevalence of ETT constriction was 22.7%. Median reduction in CSA was 7.68% (0.14–64.19%). Median increase in resistance assuming laminar and turbulent flow was 16.5% (0.3–680%) and 21% (0.3–1200%), respectively. The most common cause of constriction was the presence of a radiotherapy mouth gag. Significant associations existed between presence of constriction and rostral mispositioning, and caudal mispositioning and extreme brachycephaly. Increased severity of constriction was more likely in smaller ETT. Conclusions and clinical relevanceConstriction and mispositioning of ETT occurred very commonly in this population. Checking the ETT within the oral cavity for constriction and mispositioning is recommended. Radiotherapy mouth gags increase the risk of ETT compression. Smaller ETT are at greater risk of severe constriction. Brachycephalic dogs are at particular risk of caudal mispositioning.

Vowel height and velum position in German: Insights from a real-time magnetic resonance imaging study.

Velum position was analysed as a function of vowel height in German tense and lax vowels preceding a nasal or oral consonant. Findings from previous research suggest an interdependence between vowel height and the degree of velum lowering, with a higher velum during high vowels and a more lowered velum during low vowels. In the current study, data were presented from 33 native speakers of Standard German who were measured via non-invasive high quality real-time magnetic resonance imaging. The focus was on exploring the spatiotemporal extent of velum lowering in tense and lax /a, i, o, ø/, which was done by analysing velum movement trajectories over the course of VN and VC sequences in CVNV and CVCV sequences by means of functional principal component analysis. Analyses focused on the impact of the vowel category and vowel tenseness. Data indicated that not only the position of the velum was affected by these factors but also the timing of velum closure. Moreover, it is argued that the effect of vowel height was to be better interpreted in terms of the physiological constriction location of vowels, i.e., the specific tongue position rather than phonetic vowel height.

Spatial aerosol deposition correlated to anatomic feature development in 6-year-old upper airway computational models

The upper airways of children undergo developmental changes around age 6, yielding differences between adult and pediatric anatomies. These differences include the cricoid ring area shape, the location of narrowest constriction, and the angle of the epiglottis, all of which are expected to alter local fluid dynamic profiles and subsequent upper airway deposition and downstream aerosol delivery of inhaled therapeutics. In this work, we quantify “pediatric”-like and “adult”-like geometric and fluid dynamic features of two computed tomography (CT)-scan derived models of 6-year-old upper airways in healthy subjects and compare to an idealized model. The two CT-scan models had a mixture of “adult”- and “pediatric”-like anatomic features, with Subject B exhibiting more “pediatric”-like features than Subject A, while the idealized model exhibited entirely “adult”-like features. By computational fluid-particle dynamics, these differences in anatomical features yielded distinct local fluid profiles with altered aerosol deposition between models. Notably, the idealized model better predicted deposition characteristics of Subject A, the more “adult”-like model, including the relationship between the impaction parameter, dp2Q and the fraction of deposition across a range of flow rates and particle diameters, as well as deposition of an approximate pharmaceutical particle size distribution model. Our results with even this limited dataset suggest that there are key personalized metrics that are influenced by anatomical development, which should be considered when developing pediatric inhalable therapeutics. Quantifying anatomical development and correlating to aerosol deposition has the potential for high-throughput developmental characterization and informing desired aerosol characteristics for pediatric applications.

Effects of phonological features on reading-aloud latencies: A cross-linguistic comparison.

Most psycholinguistic models of reading aloud and of speech production do not include linguistic representations more fine-grained than the phoneme, despite the fact that the available empirical evidence suggests that feature-level representations are activated during reading aloud and speech production. In a series of masked-priming experiments that employed the reading aloud task, we investigated effects of phonological features, such as voicing, place of articulation, and constriction location, on response latencies in English and Russian. We propose a hypothesis that predicts greater likelihood of obtaining feature-priming effects when the onsets of the prime and the target share more feature values than when they share fewer. We found that prime-target pairs whose onsets differed only in voicing (e.g., /p/-/b/) primed each other consistently in Russian, as has already been found in English. Response latencies for prime-target pairs whose onsets differed in place of articulation (e.g., /b/-/d/) patterned differently in English and Russian. Prime-target pairs whose onsets differed in constriction location only (e.g., /s/ and /ʂ/) did not yield a priming effect in Russian. We conclude that feature-priming effects are modulated not only by the phonological similarity between the onsets of primes and targets but also by the dynamics of feature activation and by the language-specific relationship between orthography and phonology. Our findings suggest that feature-level representations need to be included in models of reading aloud and of speech production if we are to move forward with theorizing in these research domains. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Variation in compensatory strategies as a function of target constriction degree in post-glossectomy speech.

Individuals who have undergone treatment for oral cancer oftentimes exhibit compensatory behavior in consonant production. This pilot study investigates whether compensatory mechanisms utilized in the production of speech sounds with a given target constriction location vary systematically depending on target manner of articulation. The data reveal that compensatory strategies used to produce target alveolar segments vary systematically as a function of target manner of articulation in subtle yet meaningful ways. When target constriction degree at a particular constriction location cannot be preserved, individuals may leverage their ability to finely modulate constriction degree at multiple constriction locations along the vocal tract.

The acquisition of gestural timing

Motor plans are complex and consist not only of constriction location and degree, but also gestural timing. For children to acquire adult-like speech, they need to acquire complex timing relationships that can result in delayed acquisition. To examine this phenomenon, we examined long-distance timing patterns for English liquids, /r, l/, and short-distance timing patterns for fricatives, /θ, s, ʃ/, for 5- and 8-year-olds compared to adults. To examine the long-distance timing of liquids, I used an AV-Gated paradigm where participants saw clips of speech and predicted an upcoming /r/ or /d/ (Exp1a) or upcoming /l/ or /d/ (Exp1b). The results revealed long distance timing sequences for /r/ and /l/, with the timing for /r/ extending to at least five segments prior and /l/ 2 segments prior. However, 5-year-olds exhibited extremely long-distance timing for both /r/ and /l/, while 8-year-olds had longer distance timing for /r/ and /l/, but still not adult-like timing. Results suggest long-distance timing must be acquired. In the second experiment, we examined the dynamic COG of fricatives from 5- and 8-year-olds compared to adults. Dynamic COG results revealed significantly more vowel induced variability for/θ/ for adults than for 5- and 8-year-olds, with similar degrees of variability for /s, ʃ/. Overall, the results suggest that acquisition oftiming increases the relative complexity of acquisition, and that segment specific articulation interferes with acquisition of timing in different ways.

Phonetic Effects in the Perception of VOT in a Prevoicing Language.

Previous production studies have reported differential amounts of closure voicing in plosives depending on the location of the oral constriction (anterior vs. posterior), vocalic context (high vs. low vowels), and speaker sex. Such differences have been attributed to the aerodynamic factors related to the configuration of the cavity behind the oral constriction, with certain articulations and physiological characteristics of the speaker facilitating vocal fold vibration during closure. The current study used perceptual identification tasks to examine whether similar effects of consonantal posteriority, adjacent vowel height, and speaker sex exist in the perception of voicing. The language of investigation was Russian, a prevoicing language that uses negative VOT to signal the voicing contrast in plosives. The study used both original and resynthesized tokens for speaker sex, which allowed it to focus on the role of differences in VOT specifically. Results indicated that listeners’ judgments were significantly affected by consonantal place of articulation, with listeners accepting less voicing in velar plosives. Speaker sex showed only a marginally significant difference in the expected direction, and vowel height had no effect on perceptual responses. These findings suggest that certain phonetic factors can affect both the initial production and subsequent perception of closure voicing.

Morphological changes of the root apex in anterior teeth with periapical periodontitis: an in-vivo study

IntroductionThe aim was to analyze the morphological changes of root apex in anterior teeth with periapical periodontitis.Methods32 untreated anterior teeth with periapical periodontitis were enrolled, compared with the healthy contralateral teeth. Two-dimensional measurement of Cone-beam computed tomography was used to determine the location and measure diameter of the apical constriction according to Schell’s methods. An open-source software (3D Slicer) was used to reconstruct the teeth. The apical constriction form was analysis according to Schell’s topography. The distances of apical constriction to apical foramen and anatomical apex were measured respectively.ResultsThe difference value between buccolingual and mesiodistal diameter was (0.06 ± 0.09) mm and (0.04 ± 0.04) mm in periapical periodontitis and controls (p < 0.05). The mean distance between apical constriction and anatomical apex was significantly shorter in periapical periodontitis than controls, so was the mean distance of apical constriction to apical foramen. The most common form of apical constriction was flaring (65.6%) in periapical periodontitis.ConclusionsThe anterior teeth with periapical periodontitis had shorter distances of apical constriction to anatomical apex and apical foramen, bigger disparities between the diameters of buccolingual and mesiodistal, and higher proportion of flaring apical constriction.

Discrete constriction locations describe a comprehensive range of vocal tract shapes in the Maeda model.

The Maeda model was used to generate a large set of vocoid-producing vocal tract configurations. The resulting dataset (a) produced a comprehensive range of formant frequencies and (b) displayed discrete tongue body constriction locations (palatal, velar/uvular, and lower pharyngeal). The discrete parameterization of constriction location across the vowel space suggests this is likely a fundamental characteristic of the human vocal tract, and not limited to any specific set of vowel contrasts. These findings suggest that in addition to established articulatory-acoustic constraints, fundamental biomechanical constraints of the vocal tract may also explain such discreteness.

Effect of vocal tract morphology on tongue shaping for American English /ɹ/

There is a lack of general agreement among previous studies (e.g., Bakst, 2016; Dediu &amp; Moisik, 2019; Westbury et al., 1998) on whether measurements of vocal tract morphology are robust predictors of inter-speaker variation in tongue shaping for American English /ɹ/. One possible reason is the different quantifications of /ɹ/ tongue shapes that were employed. The current study compares the relationships between a single set of anatomical measurements and three different measures of lingual articulation for /ɹ/ in /ɑɹɑ/ in midsagittal real-time MRI data. A novel method was developed to quantify the palatal constriction location and length, which served as the first two measures of tongue shape. A linear Support Vector Machine divided the constriction location and length measures into regions that approximate the visually identified categories of “retroflex” and “bunched.” The third shape measurement is the signed distance of each token of /ɹ/ to the division boundary, representing the degree of “retroflexion” or “bunchedness” based on palatal constriction properties. These three measures showed marginally to moderately significant linear relationships with two specific measures of individual speakers’ vocal tract anatomy: the degree of mandibular inclination and the length of the oral cavity roof. Overall, the effect of anatomy on the lingual articulation of /ɹ/ is not strong. [Work supported by NSF, Grant 1908865.]

Articulatory settings and L2 English coronal consonants.

Background/aims: We explore the potential contribution of Articulatory Settings (AS) theory to L2 speech production research, testing the hypothesis that L2 segmental speech learning should involve a gradual, overall shift in both place and constriction degree, simultaneously affecting all consonants of a series as opposed to a set of parallel but unrelated changes in learners' production of individual sounds. Methods: We conducted an electropalatography study of four francophone learners' production of French and English word-initial and -medial /t d s z n l/ via carrier-sentence reading tasks. Results: L1-L2 differences in tongue shape are more common than those in constriction location, first and foremost for sonorants, and, thus, our results are not completely consistent with AS theory's claims. Conclusions: AS theory provides a potentially rich framework for exploring the L2 speech learning of consonantal phenomena including low-level L1-L2 differences in place of articulation. We propose that the observed lack of systematic between-language articulatory differences could be attributed to a number of factors to be explored in future research, such as the targeting of voicing and manner differences before the adjustment of small place differences as well as individual patterns of entrenchment of L1 articulatory routines.

English

The objectives of root canal treatment are elimination of microorganisms, removal of pulpal remnants, removal of debris, and shaping of the root canal system so that it may be obturated. The most important step in endodontic therapy is canal preparation which can be achieved by accurate working length determination. Working length determines the extent of placing the instruments into the canal, it affects the degree of pain and discomfort which the patient will experience post treatment and it plays an important role in the success of the treatment if placed within correct limits. The cementodentinal junction, where the pulp tissue changes into the apical tissue, is the ideal physiologic apical limit of WL because at this point healing is supposed to be optimal, and the wound to the periapical tissues is minimal.The apical constriction is however, histological and is impossible to locate clinically or radiographically. There are several methods of determining working length which include radiographical methods, digital tactile sense, apical periodontal sensitivity, paper point method and electronic apex locators. The requirements of an ideal method for determining working length include rapid location of the apical constriction in all pulpal conditions, easy measurement, rapid periodic monitoring and confirmation, patient and clinician comfort, minimal radiation to the patient; ease of use in special patients; and cost effectiveness. To achieve the highest degree of accuracy in working length determination, a combination of several methods should be used. This article reviews the different methods to determine WL and their clinical implications. KEY WORDS Working Length, Apex Locator, Radiographic Method.

The multifunctional spindle midzone in vertebrate cells at a glance.

During anaphase, a microtubule-containing structure called the midzone forms between the segregating chromosomes. The midzone is composed of an antiparallel array of microtubules and numerous microtubule-associated proteins that contribute to midzone formation and function. In many cells, the midzone is an important source of signals that specify the location of contractile ring assembly and constriction. The midzone also contributes to the events of anaphase by generating forces that impact chromosome segregation and spindle elongation; some midzone components contribute to both processes. The results of recent experiments have increased our understanding of the importance of the midzone, a microtubule array that has often been overlooked. This Journal of Cell Science at a Glance article will review, and illustrate on the accompanying poster, the organization, formation and dynamics of the midzone, and discuss open questions for future research.