Duration Of Constriction Research Articles

Effortful Swallow Maneuver and Modifications on Swallow Dynamics in Healthy Adults

Introduction: Effortful swallow (ES) is a widely used technique in dysphagia management, believed to strengthen oropharyngeal muscles and enhance swallowing safety and efficiency. Although its impact on the oral phase of swallowing is well documented, its effects on pharyngeal swallowing physiology remain inconsistent. This study aimed to elucidate the effects of ES on swallowing kinematics and timing, addressing existing inconsistencies in the literature. Methods: This study involved 22 healthy adults using archived videofluoroscopic swallowing studies. Participants performed three swallow trials of 10 mL puree under regular conditions and with the ES maneuver. The outcome measures comprised swallow timing and kinematic measures. Swallow timing parameters included time to maximum hyoid and laryngeal excursion, laryngeal vestibule closure (LVC) reaction and duration, pharyngeal constriction duration, pharyngoesophageal segment (PES) opening duration, and swallow duration. Swallow kinematic parameters encompassed hyoid and laryngeal excursions, pharyngeal constriction ratio, and maximum PES width. All variables were analyzed via videofluoroscopy. Paired t tests were used to examine the effect of ES on each outcome measure, with a significance threshold set at p < 0.004. Results: The ES maneuver significantly increased the duration of LVC, pharyngeal constriction, PES opening, and overall swallow duration. It also improved the pharyngeal constriction ratio. However, there were no significant changes in hyoid and laryngeal excursions. Submental muscle activity showed a notable increase during ES. Conclusion: The study demonstrates that ES can effectively modify certain temporal and kinematic aspects of swallowing, particularly by prolonging key phases and enhancing pharyngeal constriction. These findings suggest the potential utility of ES in dysphagia rehabilitation, especially in cases that require prolonged pharyngeal constriction, LVC, and PES opening. However, the limited impact on hyoid and laryngeal excursions along with LVC reaction time indicates that ES may not address all aspects of dysphagia. The findings highlight the need for tailored therapeutic approaches in dysphagia management, considering individual physiological impairment profiles.

Production and perception of stop voicing in Central Australian Aboriginal English: A cross-generational study

ABSTRACT This paper reports on a series of studies investigating the production and perception of stop voicing contrasts in speakers of Central Australian Aboriginal English (CAAE; Alice Springs, Australia). Study 1 investigated Voice Onset Time (VOT) and Constriction Duration (CD) in stop consonants in naturalistic adult speech, and the speakers produced a VOT-based voicing distinction in word-initial stops, while medial voiceless stops differ from voiced stops in having both longer VOTs and longer CDs, at least for the syllable onset position. Study 2 investigated the implementation of stop voicing contrasts (VOT and CD) in a cohort of child CAAE speakers, and the results are consistent with the adult CAAE data, suggesting predictable intergenerational transmission. Finally, Study 3 tested child speakers’ perception of stop voicing contrasts using a mispronunciation detection task, where the participants demonstrated above-chance performance for the voicing distinction across all places of articulation. Together, the findings suggest that CAAE has phonemic stop voicing distinctions, like Mainstream Australian English, and that CAAE medial stops are jointly cued by both VOT and CD, a feature shared with the contact language, Kriol.

A time-series minimally invasive transverse aortic constriction mouse model for pressure overload-induced cardiac remodeling and heart failure.

Transverse aortic constriction (TAC) is a widely-used animal model for pressure overload-induced cardiac hypertrophy and heart failure (HF). The severity of TAC-induced adverse cardiac remodeling is correlated to the degree and duration of aorta constriction. Most studies of TAC are performed with a 27-gauge needle, which is easy to cause a tremendous left ventricular overload and leads to a rapid HF, but it is accompanied by higher mortality attributed to tighter aortic arch constriction. However, a few studies are focusing on the phenotypes of TAC applied with a 25-gauge needle, which produces a mild overload to induce cardiac remodeling and has low post-operation mortality. Furthermore, the specific timeline of HF induced by TAC applied with a 25-gauge needle in C57BL/6 J mice remains unclear. In this study, C57BL/6 J mice were randomly subjected to TAC with a 25-gauge needle or sham surgery. Echocardiography, gross morphology, and histopathology were applied to evaluate time-series phenotypes in the heart after 2, 4, 6, 8, and 12 weeks. The survival rate of mice after TAC was more than 98%. All mice subjected to TAC maintained compensated cardiac remodeling during the first two weeks and began to exhibit heart failure characteristics after 4 weeks upon TAC. At 8 weeks post-TAC, the mice showed severe cardiac dysfunction, hypertrophy, and cardiac fibrosis compared to sham mice. Moreover, the mice raised a severe dilated HF at 12 weeks. This study provides an optimized method of the mild overload TAC-induced cardiac remodeling from the compensatory period to decompensatory HF in C57BL/6 J mice.

Perception of Japanese singleton and geminate contrasts: A case of Chinese learners with different dialectal backgrounds.

It is widely accepted that the Japanese language is mora-timed, and the geminate obstruent, one of the three special morae in the Japanese language, forms one independent mora. Many studies have shown that perceiving Japanese geminates accurately is especially problematic for learners of Japanese. This study examines the perception of Japanese singleton and geminate contrasts by Chinese learners of Japanese (CLJ) from different dialectal backgrounds and contrasts their perception with Japanese native speakers (JNS). This study conducted two experiments. First, non-synthesized stimuli were used to test each group of participants' perceptual sensitivity of Japanese singletons and geminates. Second, the categorical perception was accessed by adopting stimuli in which the ratio of constriction duration to entire word duration (CD/EWD) was synthesized from 15 to 60%. Results show that, although learners of Japanese had significantly lower perception levels compared to JNS regardless of their group differences (e.g., L1 background, Japanese language proficiency, etc.), they still experienced some positive transfers of L1 to achieve better perception performance. The results also suggest that CD/EWD can be considered a reliable local cue for both JNS and CLJ in categorizing Japanese singletons and geminates. In addition, the results demonstrate that variables such as medial consonant type and the learner's Japanese proficiency affect the perception of Japanese singleton and geminate contrasts.

Pupillary light responses after uncomplicated cataract surgery

AbstractPurpose: To study the effect of standard cataract surgery in the static and dynamic pupillary light responses.Methods: An observational prospective study was carried out in patients scheduled for cataract surgery. Exclusion criteria were previous ocular surgeries or diseases or intraoperative complications. Cataract surgery was done using phacoemulsification and intrasaccular monofocal intraocular lens implantation. Monocular infrared dynamic pupillometry was performed using white light (Corneal Analyser CA‐800, Topcon) just before surgery (same day), and at 1 week and 1 month after surgery. Pupil diameter was analysed under scotopic (SPD) and photopic (PPD) conditions, and latency to constriction (LC), latency to plateau (LP) and duration of constriction (DC) were also analysed. Statistical analysis was carried out with One Way ANOVA for paired data.Results: Twenty‐seven eyes from 27 patients (10 males and 17 females) were included. The mean age was 69.5 ± 9 years. Preoperative SPD and PPD values were 5.21 ± 1.1 mm and 2.78 ± 0.8 mm and decreased significantly by 1 week and 1 month after surgery (p = 0.0002 and p = 0.012, respectively). Preoperative LC, LP and DC values were 2.52 ± 0.09 s, 4.84 ± 0.35 s, and 10.9 ± 1.71 s and these values did not change significantly after surgery.Conclusions: Cataract surgery decreases the pupillary diameter both in photopic and scotopic conditions but does not modify the pupillary responses to light.

Voice onset time and constriction duration in Warlpiri stops (Australia).

This paper presents a first detailed analysis of the Voice Onset Time (VOT) and Constriction Duration (CD) of stops /p t ʈ c k/ and flap /ɽ/ in the Indigenous Australian language Warlpiri as spoken in Lajamanu Community, in Australia's Northern Territory. The results show that Warlpiri stops are realised as voiceless, long-lag stops word-initially, as well as word-medially, where /p t k/ are also characterised by CDs in excess of 100ms. This is similar to what has been reported for Kriol, and for the emerging mixed language Light Warlpiri, also spoken in the community, and by some of the participants. The results indicate that Warlpiri does not obligatorily make a word-medial distinction between stops orthographically represented by 'rt' and 'rd', which have previously been argued to be realised as /ʈ/ and /ɽ/, respectively, at least in some varieties of Warlpiri. Finally, the results also suggest that the realisation of word-initial Warlpiri flap /ɽ/ is highly variable, potentially resulting in a near-merger with /ɻ/.

When more is more: The mixed language Light Warlpiri amalgamates source language phonologies to form a near-maximal inventory

This paper presents a combined analysis of the perception and production study of the mixed language Light Warlpiri (Australia), which systematically combines elements of Warlpiri, Kriol and English. The perception and production results suggest that the Light Warlpiri phonological inventory consists of a voiced and voiceless series of stops and affricates, differentiated by Voice Onset Time (VOT) word-initially and by Constriction Duration (CD) medially, by incorporating English-like VOT differentiation and Constriction duration differences found in Kriol and also in a number of traditional Indigenous Australian languages. The results also show that Light Warlpiri speakers perceptually differentiate stops and fricatives at the same POA, but that voicing distinctions in fricatives are more difficult to discriminate than voicing distinctions in stops. The large phonological inventory of Light Warlpiri combines most features of the source languages, allowing speakers of Light Warlpiri to maintain sufficient phonemic contrasts to accommodate vocabulary items in Light Warlpiri sourced from English/Kriol as well as Warlpiri.

Gestural Properties of the Non-Target Velar Stop /k/ and Its Variance with Respect to Supralaryngeal Constrictions in C2

In this study, we examine overlap-induced gestural properties in C1. Specifically, we examine the spatio-temporal properties of the non-target velar stop /k/ in Korean, as a function of three segmental contexts in C2 (pre-/h/, pre-/p/, and pre-/t/), two-boundary conditions, and two speech-rate conditions. The results show that gestural overlap with different supralaryngeal constrictions in C2 is positively correlated with the constriction duration of /k/, and is negatively correlated with the constriction maxima. Different constrictions in C2 distinctly affect the spatio-temporal properties of C1. The pre-/t/ context leads to distinct patterns in the C1 velar stop, compared to the pre-/h/ and pre-/p/ contexts. The pre-/t/ velar stops observed in most combinatoric phonological contexts have shorter constriction durations, and have greater constriction maxima for /k(#)t/. Greater constriction maxima is also observed for the within-word condition as well as for fast speech rate. The contradictory spatio-temporal properties of /k/ seem to be determined by physiological constraints on a consecutive lingual-lingual sequence, and by a higher jaw position facilitated by a coronal.

Detecting autonomic dysfunction in patients with glaucoma using dynamic pupillometry.

Autonomic dysfunction is a feature of glaucoma patients, which are reported to be related to glaucoma progression. We investigated pupil responses to a light flash using dynamic pupillometry in glaucoma patients to assess autonomic nervous system status. In total, 97 glaucoma patients, including 21 eyes of 21 glaucoma patients with cardiac autonomic dysfunction, were enrolled. Pupil reactions were assessed using 1 flash of white light after 2 minutes of dark adaptation and recorded using dynamic pupillometry. Changes in the radius of the pupil were evaluated as a function of several time-dependent and pupil/iris (P/I) diameter ratio parameters. Autonomic function was assessed using a cardiac heart-rate-variability test which performs 5 autonomic function tests and classifies patients with cardiac autonomic neuropathy (CAN). Comparison of pupil parameters between eyes with and without disc hemorrhage indicated larger P/I ratios in darkness, greater changes in the P/I ratio during examination, shorter latency to plateau, and shorter duration of constriction in eyes with disc hemorrhages. A comparison of pupil parameters between eyes with and without CAN showed larger P/I ratios in darkness, larger P/I ratios at maximum constriction, and prolonged latency to maximum constriction. The presence of CAN was significantly related to the P/I ratio in darkness and the latency of maximum constriction. Using dynamic pupillometry, we found that glaucoma patients with CAN dysfunction have larger baseline pupils in darkness and different constriction responses to light. Assessing the pupils might be a good method of identifying patients with autonomic dysfunction.

Effect of modified Buzhong Yiqi decoction combined with pelvic floor muscle exercise-biofeedback-electrical stimulation on early stage postpartum pelvic floor dysfunction

To investigate the curative effect of modified Buzhong Yiqi decoction combined with pelvic floor muscle exercise-biofeedback-electrostimulation on early postpartum pelvic floor dysfunction disease (PFD) and its effect on the expression of transforming growth factor (TGF-β1), matrix metalloprotein (MMP-2), and tissue inhibitor of metalloproteinase (TIMP-2). A total of 186 PFD patients admitted to our hospital from March 2014 to December 2016 were selected in the study and were randomly divided into test group (n=93) and control group (n=93). The control group received pelvic floor muscle exercises-biofeedback-electrostimulation, while the test group was additionally treated with modified Buzhong Yiqi decoction based on the treatment in control group. Then the clinical efficacy was compared between two groups. The results showed that vaginal contractile electromyography (EMG), duration of vaginal constriction, dynamic vaginal pressure and pelvic floor myoelectric activity in the test group at 1, 3 and 6 months after treatment were significantly higher than those before treatment and the control group (P<0.05). The effective rate for urinary incontinence was 97.14% in test group, significantly higher than 75.68% in the control group (P<0.05). The effective rate for improvement of sexual life quality was 96.43% in test group, significantly higher than 74.07% in control group (P<0.05). 1, 3 and 6 months after treatment, the uterine prolapse, posterior wall prolapse and anterior wall prolapse grade in test group was slightly lower than that in the control group, but the difference was not statistically significant. After treatment, the levels of TGF-β1 and TIMP-2 in the test group were higher than those in the control group, while the levels of MMP-2 were lower than those in the control group (P<0.05). The results showed that modified Buzhong Yiqi decoction combined with pelvic floor muscle exercise-biofeedback-electrostimulation can effectively relieve the clinical symptoms, promote the body recovery and improve the quality of sexual life in PFD patients, with remarkable advantages, so it is worthy of popularizing.

Impaired pupillary control in "schizophrenia-like" WISKET rats.

Patients with schizophrenia show impairments in autonomic regulation, including pupillomotor control. The aim of this study was to explore the changes of pupillary light reflex in a new substrain (WISKET) with several schizophrenia-like alterations. Male WISKET rats housed individually (for four weeks) and treated with ketamine (for 3 × 5 days) after weaning and naive group-housed Wistar rats (controls) were involved in the study. The pupillary light reflex was studied in two series after sedation (diazepam) or anesthesia (chloral hydrate). Video recordings were evaluated with custom made video analyzer software. Several significant changes were observed between the two groups: the initial and minimum pupil diameters were greater, the degree of the constriction was lower, and the flatness of the curve and the total duration of constriction were shorter in the sedated WISKET rats. No other pupillary parameters (latency, amplitude and redilation) showed significant alterations. Chloral hydrate anesthesia prolonged the constriction and redilation processes compared to the sedated animals, and diminished the differences between the groups. In conclusion, WISKET rats showed disturbances in the pupillary light reflex, suggesting a general shift of autonomic balance towards a sympathetic predominance. The results provide further evidence to support the validity of WISKET rats as a complex, chronic animal model of schizophrenia.

Acoustic characteristics of liquid geminates in Japanese

Japanese contrasts consonant length. Much research has been done on the acoustic characteristics of obstruent geminates in Japanese, identifying the constriction duration as the primary acoustic correlate. The ratios of the duration of the consonants and the surrounding vowels have also been investigated, and it was pointed out that the ratios differ from some other languages with distinctive consonant length, such as Italian. The present study examines the acoustics of liquid geminates in Japanese. Phonological phenomena in Japanese such as verb inflection demonstrate that the language dislikes liquid geminates. However, while not as common as obstruent or nasal geminates, liquid geminates are not impossible; they are present in certain loanwords and emphatic expressions. I report on the acoustic correlates of liquid geminates focusing on consonant sonority and consonant-vowel ratio, in three environments controlled for vowel quality and pitch-accent position: namely, loanwords (mostly from Italian and Arabic), emphatic forms of adjectives (e.g., karai “spicy” &amp;gt; karrai) and emphatic forms of onomatopoeic expressions (e.g., garagara “expresses emptiness” &amp;gt; garragara), pronounced by three native speakers of Tokyo dialect of Japanese in laboratory settings.

The consonant length contrast in Persian: Production and perception

Across languages, there is a tendency to avoid length contrasts in the most vowel-like consonant classes, such as glides or laryngeals. Such gaps could arise from the difficulty of determining where the boundary between vowel and consonant lies when the transition between them is gradual. This claim is tested in Persian (Farsi), which has length contrasts in all classes of consonants, including glides and laryngeals. Persian geminates were compared to singletons in three different speaking rates and seven different consonant classes. Geminates were found to have longer constriction intervals than singletons, and this length effect interacted with both speaking rate and manner of articulation. In one of two perception experiments, Persian speakers identified consonants as geminate or singleton in stimuli in which the constriction duration was systematically varied. The perceptual boundary between geminates and singletons was most sharply defined for obstruents and least so for laryngeals, as reflected by the breadth of the changeover region in the identification curve. In the other perception experiment, subjects identified the length class of glides differing in constriction duration and formant transition duration. Longer formant transitions led to more geminate responses and to a broader changeover interval.

Articulatory reflexes of the three-way contrast in labial stops and kinematic evidence for domain-initial strengthening in Korean

This study examines articulatory characteristics of the three-way contrast in labial stops /p php*/ (lenis, aspirated, fortis, respectively) in Korean in phrase-initial and phrase-medial prosodic positions with a two-fold goal. First, it investigates supralaryngeal articulatory reflexes of the stops and explores articulatory invariance of these stops across prosodic positions. Second, it investigates Korean stops in kinematic terms from the perspective of domain-initial strengthening, and explores the nature of prosodically-conditioned speech production from a dynamical perspective. Results showed that the articulatory reflex of the three-way contrast was invariantly observed across prosodic positions with lip constriction degree (/p/&lt;/ph/&lt;/p*/), while lip constriction duration showed a binary distinction (/p/&lt;/php*/). Kinematically, there was only very weak articulatory evidence for the contrast across prosodic positions: The V-to-C lip closing movement tended to be faster for /ph/ than for /p/, and the C-to-V lip opening movement tended to be larger for /php*/ than for /p/. As for domain-initial strengthening, the consonantal lip closing gesture was characterized by a larger, longer and slower articulation, whereas the vocalic lip opening gesture (after the release) was larger and faster, but not longer. Kinematic relations indicated that the lip closing movement is most likely controlled by a rate of the clock (possibly modulated by a temporal modulation gesture, or π-gesture) comparable to boundary effects in English, but the boundary-induced lip opening movement was better accounted for by a change in target (possibly modulated by a spatial modulation gesture, or μ-gesture) which was comparable to prominence rather than boundary effects in English. The cross-linguistic difference was interpreted as coming from different prosodic systems between Korean and English, presumably instantiated in dynamical terms of how the temporal and the spatial modulation gestures are phased with constriction gestures in relation to boundary marking versus prominence marking.

Assessing pharyngeal function for brainstem stroke survivors with dysphagia using videofluoroscopy digital analysis

Objective To evaluate the effect of the modified balloon dilatation intervention on the pharyngeal constriction function of the brainstem stroke survivors with dysphagia using videofluoroscopy-based digital analysis. Methods Thirty brainstem stroke survivors with pharyngeal dysphagia were recruited and randomly divided into a treatment group and a control group, with 15 in each. The treatment group was treated with the modified balloon dilatation in addition to the routine treatment of 30min, respectively, once a daily, 3 days a week, whiled a control group was treated with routine treatment of 30min twice a day, 3 days a week. Before and after the treatment, the rate and duration of pharyngeal constriction were measured in both groups. Results After the treatment, the rate of pharyngeal constriction in the treatment group was (0.20±0.030), (0.14±0.05) and (0.15±0.04) when swallowing thin liquid, thick liquid and pasty food, significantly better than before the treatment. The duration of the pharyngeal constriction was (990.34±96.14), (1010.47±133.64) and (1180.10±121.27) ms, respectively, also significantly better than before the treatment. In the control group, significant differences were also observed in the rate and duration of pharyngeal constriction before and after the treatment. Conclusions Digital analysis based on videofluoroscopy can be used to quantify swallowing function effectively, and the rate and duration of pharyngeal constriction can be used to evaluate the pharyngeal function before and after treatment. Key words: Stroke; Deglutition disorders; Videofluoroscopy; Balloon dilatation

Korean /l/-flapping in an /i/-/i/ context

In this study, we aim to describe kinematic characteristics of Korean /l/-flapping in two speech rates (fast vs. comfortable). Production data was collected from seven native speakers of Seoul Korean (four females and three males) using electromagnetic midsagittal articulometry (EMMA), which provided two dimensional data on the x-y plane. We examined kinematic properties of the vertical/horizontal tongue tip gesture, the vertical/horizontal (rear) tongue body gesture, and the jaw gesture in an /i/-/i/ context. Gestural landmarks of the vertical tongue tip gesture are directly measured. This serves as the actual anchoring time points to which relevant measures of other trajectories referred. The study focuses on velocity profiles, closing/opening spatiotemporal properties, constriction duration, and constriction minima were analyzed. The results are summarized as follows. First, gradiently distributed spatiotemporal values of the vertical tongue tip gesture were on a continuum. This shows more of a reduction in fast speech rate, but no single instance of categorical reduction (deletion). Second, Korean /l/-flapping predominantly exhibited a backward sliding tongue tip movement, in 83% of production, which is apparently distinguished from forward sliding movement in English. Lastly, there was an indication of vocalic reduction in fast rate, truncating spatial displacement of the jaw and the tongue body, although we did not observe positional variations with speech rate. The present study shows that Korean /l/-flapping is characterized by mixed articulatory properties with respect to flapping sounds of other languages such as English and Xiangxiang Chinese. Korean /l/ flapping demonstrates a language-universal property, such as the gradient nature of its flapping sounds that is compatible with other languages. On the other hand, Korean /l/-flapping also shows a language-particular property, particularly distinguished from English, in that a backward gliding movement occurs during the tongue tip closing movement. Although, there was no vocalic reduction in V2 observed in terms of jaw and tongue body height, spatial displacement of these articulators still suggests truncation in fast speech rate.

The Obstruent Inventory of Roper Kriol

Roper Kriol is a major variety of the largest Indigenous Australian language, Kriol, yet its phonology remains under-described and it has never been examined instrumentally. Reports suggest high variability. We present a lexical survey with native Kriol speakers followed by two acoustic studies of the obstruent inventory with literate speakers, and finally an acoustic analysis of naturally occurring speech. We conclude that the obstruent inventory has inherited features from the substrate languages and English. It has contrastive stop voicing using Voice Onset Time differences in an English-like manner. It also has contrastive fricatives, but no voicing distinction in these phonemes. Like some of the substrate languages, stops also contrast in constriction duration to a much greater degree than English. There is no evidence that voicing is a variable phenomenon, and we suggest that the reported variability is due to language shift over several generations from a situation where it was primarily an L2 used by speakers of the substrate languages to the stabilized L1 form of Kriol described here. We argue that the creole continuum is unlikely to apply to true phonemic inventory differences, as opposed to surface phonetic forms and other aspects of grammar such as lexical choice.

Abstract 18510: Pericardiectomy Impact on Cardiac Index in Patients With Constrictive Pericarditis

Background: Advanced constrictive pericarditis (CP) has been associated with change in cardiac hemodynamics including cardiac output and cardiac index (CI). Etiology and duration of constriction can affect recovery of CI postpericardiectomy. We sought to look into the change in post-operative cardiac index (CI) among different CP etiologies using echocardiogram and right heart catheterization. Methods: We Included 301 patients from Cleveland Clinic pericardial disease database with surgically confirmed CP form 1999 to 2010. Post-operative CI was measured using Fick method immediately before and after pericardiectomy. The bootstrap-validated analysis of covariates was performed to compare the mean of post-operative CI among different CP etiologies after adjustment with baseline relevant covariates. Results: Etiology of CP was idiopathic in 136 patients (45%), viral in 24 patients (8%), prior cardiac surgery in 89 patients (30%), autoimmune in 30 patients (10%) and radiation treatment in 22 patients (7%). Mean CI was reduced and improved after pericardiectomy (2.1±0.7 L/min/m2 to 3.0±0.8 L/min/m2, p&lt;0.001). After adjustment for age, gender, NYHA, LVEF, RVSP, medial e’, lateral e’ and pre-operative CI, the post-operative CI recovered based on different etiologies (2.99±0.7, 3.07±0.16, 3.00±0.09, 3.48±0.15 and 2.76±0.17 L/min/m2 for Idiopathic, viral, prior cardiac surgery, autoimmune and post radiation respectively, p=0.019) (Figure1). Conclusion: Post-operative cardiac index recovery is related to underlying etiology. Considering CP etiology for patient selection for pericardiectomy may identify patients who will benefit from the surgery and avoid post-pericardiectomy low cardiac output syndrome that may lead to early post-operative mortality

Articulatory Attributes in Korean Nonassimilating Contexts

This study examined several kinematic properties of the primary articulator (the tongue dorsum) and the supplementary articulator (the jaw) in the articulation of the voiceless velar stop (/k/) within nonassimilating contexts. We examined in particular the spatiotemporal properties (constriction duration and constriction maxima) from the constriction onset to the constriction offset by analyzing a velar (/k/) followed by the coronal fricative (/s/), the coronal stop (/t/), and the labial (/p/) in across-word boundary conditions (/k#s/, /k#t/, and /k#p/). Along with these measurements, we investigated intergestural temporal coordination between C1 and C2 and the jaw articulator in relation to its coordination with the articulation of consonant sequences. The articulatory movement data was collected by means of electromagnetic midsagittal articulometry (EMMA). Four native speakers of Seoul Korean participated in the laboratory experiment. The results showed several characteristics. First, a velar (/k/) in C1 was not categorically reduced. Constriction duration and constriction degree of the velar (/k/) were similar within nonassimilating contexts (/k#s/

Snake modulates constriction in response to prey's heartbeat

Many species of snakes use constriction-the act of applying pressure via loops of their trunk-to subdue and kill their prey. Constriction is costly and snakes must therefore constrict their prey just long enough to ensure death. However, it remains unknown how snakes determine when their prey is dead. Here, we demonstrate that boas (Boa constrictor) have the remarkable ability to detect a heartbeat in their prey and, based on this signal, modify the pressure and duration of constriction accordingly. We monitored pressure generated by snakes as they struck and constricted warm cadaveric rats instrumented with a simulated heart. Snakes responded to the beating heart by constricting longer and with greater total pressure than when constricting rats with no heartbeat. When the heart was stopped midway through the constriction, snakes abandoned constriction shortly after the heartbeat ceased. Furthermore, snakes naive to live prey also responded to the simulated heart, suggesting that this behaviour is at least partly innate. These results are an example of how snakes integrate physiological cues from their prey to modulate a complex and ancient behavioural pattern.