Closure Duration Research Articles

Evaluation of Unintended Social and Economic Consequences of an Unplanned School Closure in Rural Illinois.

ABSTRACT BACKGROUND School closure is one of the primary measures considered during severe influenza pandemics and other emergencies. However, prolonged school closures may cause unintended adverse consequences to schools, students, and their families. A better understanding of these consequences will inform prepandemic planning, and help public health and education authorities in making informed decisions when considering school closures. METHODS We conducted a household survey and interviewed school officials following an 8‐day long closure of a school district in rural Illinois. We described household responses regarding difficulties of school closure, and summarized main themes from school official interviews. RESULTS A total of 208 (27%) household surveys were completed and returned. This school closure caused difficulties to 36 (17%) households; uncertain duration of closure, childcare arrangements, and lost pay were the most often reported difficulties. Having 1 adult in the household losing pay and household income below $25,000 were significantly associated with overall difficulty during this school closure. Concern about student health and safety was the most frequent theme in school administrator interviews. CONCLUSIONS Whereas the majority of responding households did not report difficulties during this school closure, households with 1 adult losing pay during the closure reported incurring additional expenses for childcare.

A geomorphic classification of intermittently open/closed estuaries (IOCE) derived from estuaries in Victoria, Australia

A large proportion of estuaries along microtidal wave-dominated coastlines worldwide have entrances that intermittently close to the ocean when tidal currents and fluvial discharge are insufficient to erode sediment delivered onshore by waves. In this study, these systems are termed “intermittently open/closed estuaries” (IOCE) in order to include all estuaries which intermittently close to the ocean. IOCE do not fit neatly into existing generalized estuary classification models and have been traditionally recognized as a single estuary type that constitute a rare subset of wave-dominated estuaries. In this study, 111 estuaries in Victoria, Australia, are used to develop a classification model that delineates between different IOCE types. This was undertaken using historic aerial imagery and quantification of the estuary channel width, catchment area, lagoon dimensions and tidal prism derived from remotely sensed data. Field surveying of entrance morphology was undertaken for a subsample of 35 IOCE characteristic of each section of the coast and which had detailed entrance condition records. Using this subset, IOCE were classified into three distinct types using multiple methods of statistical delineation (non-metric multidimensional scaling, hierarchical cluster analysis and distribution analysis). These three types are: (1) Type A, the largest IOCE which both close and open infrequently but for the longest durations; (2) Type B, medium sized IOCE which open and close several times per year for weekly to monthly durations; and (3) Type C (tidal creeks), the smallest IOCE located specifically in high rainfall, mountainous catchments and which exist in a predominantly open state. The three types of IOCE showed an order of magnitude difference in entrance closure duration as controlled by variations in the catchment area, tidal prism volume, dimensions of the estuarine lagoon and the entrance channel at the mouth. The classification is also applicable to wave-dominated coastlines internationally where IOCE are present.

A Single Intercostal Space Thoracoscopic Approach for Minimally Invasive Ivor Lewis Esophagectomy.

We present a laparoscopic and single intercostal space thoracoscopic approach (SICS group) for Ivor Lewis minimally invasive esophagectomy (MIE) and provide postoperative analgesia with a continuous multiple intercostal nerve blocking technique. The characters of this technique are evaluated. From October 2015 to April 2016, 18 consecutive patients with esophageal cancer were treated with Ivor Lewis MIE by a SICS group. Moreover, from July 2014 to September 2015, 48 patients with esophageal cancer received Ivor Lewis MIE by four-port video-assisted thoracic surgery (VATS) approach. Among those patients, by using propensity-score matching, 18 matched patients who underwent four-port VATS MIE (four-port group) were retrospectively selected for further statistical analysis. Patient demographics, short-term postoperative outcomes were recorded. None of the patients in the SICS group required conversion to an open procedure. No failure of the intrathoracic esophagogastrostomy occurred. No perioperative mortality or readmission was observed in this series. No patient suffered from anastomotic leak or complained remarkable dysphasia during follow-up. SICS group had a shorter duration of both docking procedure and closure of chest incisions compared with four-port group. The visual analog scale (VAS) pain scores on 24 hours after surgery was significantly lower in SICS group than in four-port group, while the values on 6 hours were comparable. The level of creatine kinase on postoperative day (POD) 1 was significantly lower in SICS group than in four-port group. Single intercostal space thoracoscopic procedure is safe and technically feasible and can therefore be viewed as an attractive alternative approach for performing Ivor Lewis MIE.

Juvenile Steelhead Locate Coldwater Refugia in an Intermittently Closed Estuary

AbstractMany coastal estuaries in Mediterranean climates are susceptible to inlet closures resulting from barrier beach formation. These closures are ecologically important because they eliminate tidal exchange and connectivity of nekton movement to the coastal ocean and, depending on closure duration, can convert a dynamic estuary into a quiescent lagoon. Although closures can create lethal or stressful conditions for nekton and benthic communities, especially obligate diadromous species, under some conditions they can enhance survival of juvenile steelhead Oncorhynchus mykiss. However, the mechanisms explaining how closed conditions enhance the growth of juvenile steelhead and how inhabitants avoid physiologically stressful conditions remain unknown. In the present study, recent technological advances in sensor‐encoded acoustic telemetry provided the ability to simultaneously locate and determine the temperature of juvenile steelhead as small as 93 mm FL by using mobile and stationary tracking. In the Russian River estuary, an intermittently closed estuary in northern California, we used acoustic telemetry to infer water quality exposure by linking the temperature of individually tagged fish with water quality profiles collected in close proximity. Under open‐inlet conditions, juvenile steelhead experienced primarily brackish and saline water in the lower and middle reaches and warm freshwater in the upper reach, whereas under closed‐inlet conditions they experienced warm freshwater in the middle and upper reaches. During closed conditions, juvenile steelhead displayed behavior that suggested the ability to mediate stressful environmental conditions; specifically, they responded to closed conditions by moving greater distances and aggregating near thermal refugia. Our findings show the importance of recognizing these strategies when contemplating changes to estuary management and highlight the significance of tributary hydrogeomorphic processes and groundwater linkages in subwatersheds that are sources of cool water for thermal refugia in intermittently closed estuaries.Received August 5, 2016; accepted February 27, 2017 Published online May 11, 2017

Stigma Sensitivity and the Duration of Temporary Closure Are Affected by Pollinator Identity in Mazus miquelii (Phrymaceae), a Species with Bilobed Stigma.

A sensitive bilobed stigma is thought to assure reproduction, avoid selfing and promote outcrossing. In addition, it may also play a role in pollinator selection since only pollinators with the appropriate body size can trigger this mechanism. However, no experimental study has investigated how the sensitive stigma responds to different pollinators and its potential effects on pollination. Mazus miquelii (Phrymaceae), a plant with a bilobed stigma was studied to investigate the relationship between stigma behaviors and its multiple insect pollinators. The reaction time of stigma closure after touched, duration of temporary closure, and factors determining permanent closure of the stigma were studied when flowers were exposed to different visitors and conducted with hand pollination. Manual stimulation was also used to detect the potential differences in stigmas when touched with different degrees of external forces. Results indicated that, compared to pollinators with a small body size, larger pollinators transferred more pollen grains to the stigma, causing a rapid stigma response and resulting in a higher percentage of permanent closures. Duration of temporary closure was negatively correlated with the speed of stigma closure; a stigma that closed more rapidly reopened more slowly. Manual stimulation showed that reaction time of stigma closure was likely a response to external mechanical forces. Hand pollination treatments revealed that the permanent closure of a stigma was determined by the size of stigmatic pollen load. For large pollinators, the speedy reaction of the stigma might help to reduce pollen loss, enhance pollen germination and avoid obstructing pollen export. Stigmas showed low sensitivity when touched by inferior pollinators, which may have increased the possibility of pollen deposition by subsequent visits. Therefore, the stigma behavior in M. miquelii is likely a mechanism of pollinator selection to maximize pollination success.

A Retrospective Analysis of Surgical Femoral Artery Closure Techniques: Conventional versus Purse Suture Technique

Different techniques have been reported for the exploration and repair of femoral artery (FA) in patients who undergo minimally invasive cardiac surgery (MICS) and endovascular aortic surgery. We used a modified approach alternative to the conventional technique (group CT) since May 2013, which specifies a shorter groin incision and diamond-shaped hemostatic purse sutures for arteriotomy closure without the requirement of cross-clamping (group PT [purse suture technique]) and evaluated early outcomes and the complication profiles of the 2 techniques for femoral access. In our clinic, between May 2011 and December 2015, 503 FA cannulations were performed on 345 patients who underwent MICS (n=109, mean age 64.1±17.6 years, female/male ratio 71/38), endovascular abdominal aneurysm repair (n=158, mean age 71.3±10.2 years, female/male ratio 63/95), thoracal endovascular aneurysm repair (n=50, mean age 65.0±15.3 years, female/male ratio 15/35), and transaortic valve implantation (n=28, mean age 80.8±5.9 years, female/male ratio 13/15). A total of 295 FAs were exposed via mini incision and were repaired with the PT. We compared the duration of femoral closure (FC), wound infection, and vascular complications including bleeding hematoma, thromboembolic and ischemic events, pseudoaneurysm, seroma, surgical reintervention rates, delayed hospital stay for groin complications, and existence of postoperative local luminal narrowing (LLN) at the intervention site over 25% for both groups. FC time (CT 14.9±3.16min, PT 6.5±1.12min, P<0.0001), bleeding hematoma frequency (CT 6.2%, PT 1.7%, P=0.01), and prolonged hospital stay for groin complications (CT 14.9%, PT 3.4%, P<0.0001) were significantly lower in the PT group. Rate of technical success (CT 80.3%, PT 87.4%, P=0.03) and event-free patient (CT 66.1%, PT 77.5%, P=0.03) were significantly better in the PT group. There were no differences between groups in terms of ischemic events, wound infection rates, development of pseudoaneurysm and seroma, surgical reintervention rates, and LLN of FA over 25% at 6-month duplex evaluation. The comparison of the 2 approaches revealed the advantages of the PT in terms of bleeding hematoma and shortening in FC time and the length of hospital stay. We suggest performing a smaller skin incision for FA access and utilizing purse sutures, which allows completing the procedure without cross-clamping, thus providing a favorable approach and excellent comfort for the surgeon.

Laryngeal evidence for the first and second passaggio in professionally trained sopranos.

IntroductionDue to a lack of empirical data, the current understanding of the laryngeal mechanics in the passaggio regions (i.e., the fundamental frequency ranges where vocal registration events usually occur) of the female singing voice is still limited.Material and methodsIn this study the first and second passaggio regions of 10 professionally trained female classical soprano singers were analyzed. The sopranos performed pitch glides from A3 (ƒo = 220 Hz) to A4 (ƒo = 440 Hz) and from A4 (ƒo = 440 Hz) to A5 (ƒo = 880 Hz) on the vowel [iː]. Vocal fold vibration was assessed with trans-nasal high speed videoendoscopy at 20,000 fps, complemented by simultaneous electroglottographic (EGG) and acoustic recordings. Register breaks were perceptually rated by 12 voice experts. Voice stability was documented with the EGG-based sample entropy. Glottal opening and closing patterns during the passaggi were analyzed, supplemented with open quotient data extracted from the glottal area waveform.ResultsIn both the first and the second passaggio, variations of vocal fold vibration patterns were found. Four distinct patterns emerged: smooth transitions with either increasing or decreasing durations of glottal closure, abrupt register transitions, and intermediate loss of vocal fold contact. Audible register transitions (in both the first and second passaggi) generally coincided with higher sample entropy values and higher open quotient variance through the respective passaggi.ConclusionsNoteworthy vocal fold oscillatory registration events occur in both the first and the second passaggio even in professional sopranos. The respective transitions are hypothesized to be caused by either (a) a change of laryngeal biomechanical properties; or by (b) vocal tract resonance effects, constituting level 2 source-filter interactions.

Laryngeal Closure during Swallowing in Stroke Survivors with Cortical or Subcortical Lesion

One of the major, and most harmful, symptoms of dysphagia in stroke survivors is aspiration. Survivors of unilateral cortical strokes with dysphagia and resulting aspiration have been reported to have greater initiation delays in laryngeal closure than those who did not aspirate. Few studies have reported such data in survivors of subcortical stroke. This study measured initiation of laryngeal closure (ILC) and laryngeal closure duration (LCD) in 2 groups of subjects: 15 stroke survivors with cortical lesions and 15 stroke survivors with subcortical lesions. Means and standard deviations of ILC and LCD were analyzed on 5-mL thin liquid and 5-mL puree boluses using a 100-ms timer during subsequent analysis of videofluoroscopic swallowing examinations. Statistical comparisons were used by repeated measures analysis of variance. Significance level was set at P < .05. ILC was significantly longer in stroke survivors with a subcortical lesion than in those with a cortical lesion for both bolus consistencies. However, there were no significant differences between the 2 groups in LCD. Stroke survivors with a subcortical lesion had a greater incidence of penetration or aspiration and silent aspiration than those with a cortical lesion and a longer delay in the ILC. Subcortical lesions may put these survivors at greater risk of aspiration due to delayed initial laryngeal closure and reduced oral and laryngeal sensation. The subcortical damage, which occurs at the basal ganglia, may interrupt the ILC.

An experimental study on backdraught: The dependence on temperature

This paper presents the results of a series of reduced scale experiments to investigate the temperature conditions leading to backdraught in a fire compartment (0.8m×0.4m×0.4m), using solid polypropylene pellets as the fuel. The factors of primary interest are the pre-burn time, before the fire becomes oxygen limited, the duration of door closure, and the temperature distribution in the compartment. It is shown that the temperature inside the compartment is crucial for the occurrence of backdraught. Above 350°C, backdraught by auto-ignition is possible. If a pilot spark is present, backdraught may occur at temperatures down to 300°C. It is shown that backdraught conditions can be achieved in the early stages of a fire as long as a suitable temperature is reached, at considerably lower temperatures than those generated during flashover. Further investigation on gas concentration is essential to understand the chemistry of backdraught combustion.

Mandarin Chinese Speakers’ Production of English Vowel Duration as a Function of Coda Voicing and Syllable Number

The current study compared native English-speaking adults’ and native Mandarin-speaking adults’ ability to produce context-specific vowel duration differences under the assumption that variability is higher in non-native language learners’ production. A total of twenty native Mandarin and English speakers produced real English words in a frame sentence multiple times. The mean vowel and consonant closure duration and vowel duration variability were analyzed. The results were that Mandarin Chinese speakers produced considerably smaller contrasts but greater temporal variability than English speakers in their production of individual words. The results indicated that the phonological knowledge of L1 is likely to interfere with the temporal patterns of L2 production.

Examination of swallowing maneuver training and transfer of practiced behaviors to laryngeal vestibule kinematics in functional swallowing of healthy adults

Swallowing maneuvers are routinely trained in dysphagia rehabilitation with the assumption that practiced behaviors transfer to functional swallowing, however transfer is rarely examined in the deglutition literature. The goal of this study was to train the volitional laryngeal vestibule closure (vLVC) maneuver, which is a swallowing maneuver that targets prolonged laryngeal vestibule closure (LVC). In two different training experiments, 69 healthy adults underwent Long-hold (hold vLVC as long as possible) or Short-hold vLVC training (hold vLVC for 2s). Before and after vLVC training, natural swallows (swallowing without a therapeutic technique) were completed. The outcome variables included laryngeal vestibule closure reaction time and the duration of laryngeal vestibule closure. Results indicate that during both Long-hold and Short-hold vLVC trainings, vLVC swallows had faster laryngeal vestibule closure reaction times and longer durations of laryngeal vestibule closure than in pre-training 5ml liquid swallows. However, only faster laryngeal vestibule closure reaction times transferred to post-training 5ml liquid swallows (20–24% faster), but not prolonged durations of laryngeal vestibule closure. Our findings suggest that swallowing maneuver training has the potential to induce transfer of what was practiced to functional swallowing behavior, although not all practiced behaviors may generalize. These findings are significant for bolstering the effectiveness of dysphagia management in medical settings and should be tested in individuals with dysphagia.

Losing one's touch: Evolution of the touch‐sensitive stigma in the Mimulus guttatus species complex

The stigmas of several species are touch sensitive and respond to pressure by closing. Previous research suggests that stigma closure could prevent self pollination within a flower during a pollinator's visit or enhance male function by increasing pollen export. Both factors could be favored in outcrossers, and neither would be beneficial in selfers. We investigated variation in stigma-closing and the duration of closure in annual and perennial populations of the variable species Mimulus guttatus and whether four closely related selfing species (M. cupriphilus, M. laciniatus, M. nasutus, and M. pardalis) have lost their touch sensitivity. We grew plants in a controlled environment and performed experiments with and without the addition of pollen to the stigma. In M. guttatus, the speed of stigma-closing was rapid and unaffected by the deposition of pollen. Populations varied significantly in closing speed, which may reflect their geographic location. For annual populations only, anther-stigma separation significantly affected closing speed. Also, stigmas that closed quickly stayed closed longer, and stigmas that received pollen remained closed longer. Finally, in the selfing species, stigma-closing was more variable; some populations have entirely lost the ability to respond to touch. We discuss our results in the context of traits that promote outcrossing and traits that are under selection during the evolution of selfing. This is the first characterization of variation in touch responses across multiple populations within a species and the first to demonstrate the loss of touch sensitivity in selfing lineages.

Can variations in visual behavior measures be good predictors of driver sleepiness? A real driving test study

ABSTRACTObjective: The primary purpose of this study was to examine the association between variations in visual behavior measures and subjective sleepiness levels across age groups over time to determine a quantitative method of measuring drivers' sleepiness levels.Method: A total of 128 volunteer drivers in 4 age groups were asked to finish 2-, 3-, and 4-h continuous driving tasks on expressways, during which the driver's fixation, saccade, and blink measures were recorded by an eye-tracking system and the subjective sleepiness level was measured through the Stanford Sleepiness Scale. Two-way repeated measures analysis of variance was then used to examine the change in visual behavior measures across age groups over time and compare the interactive effects of these 2 factors on the dependent visual measures.Results: Drivers' visual behavior measures and subjective sleepiness levels vary significantly over time but not across age groups. A statistically significant interaction between age group and driving duration was found in drivers' pupil diameter, deviation of search angle, saccade amplitude, blink frequency, blink duration, and closure duration. Additionally, change in a driver's subjective sleepiness level is positively or negatively associated with variation in visual behavior measures, and such relationships can be expressed in regression models for different period of driving duration.Conclusions: Driving duration affects drivers' sleepiness significantly, so the amount of continuous driving time should be strictly controlled. Moreover, driving sleepiness can be quantified through the change rate of drivers' visual behavior measures to alert drivers of sleepiness risk and to encourage rest periods. These results provide insight into potential strategies for reducing and preventing traffic accidents and injuries.

Measuring Competency Development in Objective Evaluation of Videofluoroscopic Swallowing Studies.

Clinical interpretation of videofluoroscopic swallow study (VFSS) has often been criticized for its poor objectivity and inter-rater agreement. In order to address this, objective VFSS measures have been developed, reported and demonstrated to be valid and reliable. However, widespread clinical implementation is lacking. Reasons cited include lack of training and excessive time taken to perform measures. This study investigated competency development in selected standardized objective VFSS measures among speech-language pathologists (SLPs) naive to quantitative measurement. Six novice (no VFSS experience) and four experienced (2-10years of VFSS experience) SLPs participated in 4h of training in how to perform selected objective VFSS measures including pharyngeal constriction ratio, maximum pharyngoesophageal opening, pharyngoesophageal opening duration, airway closure duration and total pharyngeal transit time. Each week for eight weeks, participants were asked to independently measure and report three VFSS of patients affected by stroke. By week 8, all SLPs, irrespective of prior experience level, were able to achieve 80% accuracy in measures in comparison to the consensus of three expert clinicians. SLPs' mean time for completion reduced from 50min in week 1-25min in week 8. Inter-rater agreement for measures improved across the eight-week period (range ICC=-31.05 to .60 in week 1 to ICC=.71 to .98 in week 8). There was high agreement in location of impairment and consequent management recommendations by week 8. In conclusion, SLPs can reliably learn and incorporate objective VFSS measures within a reasonable time frame. Level of experience has limited influence on the learning curve.

Effects of Chin-Down Maneuver on the Parameters of Swallowing Function After Esophagectomy With 3-Field Lymphadenectomy Examined by Videofluoroscopy

ObjectivesTo determine the effect of the chin-down maneuver after esophagectomy with 3-field lymphadenectomy (3FL) on pharyngeal residue, upper esophageal sphincter (UES) opening, and laryngeal closure. DesignProspective data were collected from a pharyngeal videofluoroscopic swallowing study. SettingDysphagia clinics. ParticipantsPatients selected according to the inclusion criteria (N=14; mean age, 65.9y) from a total of 43 patients who underwent esophagectomy with 3FL from May to December 2014 were enrolled. InterventionsVideofluoroscopy was conducted in head-neutral and chin-down positions to measure the pharyngeal constriction ratio (PCR), amount of residue in the vallecula and pyriform sinus after the first swallow, UES opening diameter, duration of UES opening, and duration of laryngeal vestibule closure. Main Outcome MeasuresThe aforementioned parameters were compared statistically between the head-neutral and chin-down positions. ResultsIn comparison with the neutral group, the PCR and residue in the pyriform sinus were significantly smaller in the chin-down group (P<.01). However, the residue in the vallecula did not differ significantly from that of the neutral group (P=.44). The UES opening diameter, duration of UES opening, and duration of laryngeal vestibule closure were all significantly larger in the chin-down group than in the neutral group (P<.05). ConclusionsThis study demonstrates that use of the chin-down maneuver after esophagectomy with 3FL can help expedite swallowing by strengthening pharyngeal constriction, widening the UES, and enhancing laryngeal closure.

Modeling and Simulating Passenger Behavior for a Station Closure in a Rail Transit Network.

A station closure is an abnormal operational situation in which the entrances or exits of a rail transit station have to be closed for some time due to an unexpected incident. A novel approach is developed to estimate the impacts of the alternative station closure scenarios on both passenger behavioral choices at the individual level and passenger demand at the disaggregate level in a rail transit network. Therefore, the contributions of this study are two-fold: (1) A basic passenger behavior optimization model is mathematically constructed based on 0–1 integer programming to describe passengers’ responses to alternative origin station closure scenarios and destination station closure scenarios; this model also considers the availability of multi-mode transportation and the uncertain duration of the station closure; (2) An integrated solution algorithm based on the passenger simulation is developed to solve the proposed model and to estimate the effects of a station closure on passenger demand in a rail transit network. Furthermore, 13 groups of numerical experiments based on the Beijing rail transit network are performed as case studies with 2,074,267 records of smart card data. The comparisons of the model outputs and the manual survey show that the accuracy of our proposed behavior optimization model is approximately 80%. The results also show that our model can be used to capture the passenger behavior and to quantitatively estimate the effects of alternative closure scenarios on passenger flow demand for the rail transit network. Moreover, the closure duration and its overestimation greatly influence the individual behavioral choices of the affected passengers and the passenger demand. Furthermore, if the rail transit operator can more accurately estimate the closure duration (namely, as g approaches 1), the impact of the closure can be somewhat mitigated.

The Phonetic Characteristics in Patients of Bilateral Vocal Fold Paralysis Without Tracheotomy.

ObjectivesPatients with bilateral vocal fold paralysis (BVFP) theoretically have difficulty producing voiceless consonants. However, perceptual studies have revealed clear production of voiceless consonants with good articulation scores in nontracheostomized patients. The purpose of this study was to clarify the production of voiceless stops during articulation in patients with BVFP compared to normal speakers.MethodsThe perceptual, acoustic, and aerodynamic characteristics of patients with BVFP and those with normal speech were investigated with special reference to voiceless stop consonants. Test words were prepared to place the stop consonants in different phonological environments, and were all nonsense words.ResultsThe patients with BVFP perceptually produced the three types of stops successfully. However, they acoustically varied voice onset time to produce phonetically representative stops but decreased voice onset time of /ph/ and /p/ compared to those of normal speakers. These patients may properly control air pressure to produce the three types of stop consonants similar to normal speakers.ConclusionThe patients with BVFP realized the distinctions between the three types of stops similar to the normal speakers. Although vocal mobility was absent in the patients with BVFP, voice onset time, vowel duration, closure duration, and air pressure were similar to those of normal speakers.

THE ANALYSIS OF SPONTANEOUS CLOSURE MECHANISMS AND REGENERATION OF RETINAL LAYERS OF A FULL-THICKNESS MACULAR HOLE: Relationship with Visual Acuity Improvement.

To analyze the spontaneous closure mechanisms, retinal layer regeneration, and best corrected visual acuity (BCVA) in the full-thickness macular hole (FMTH). Ten eyes of 10 patients were studied. The measured outcomes included the time of persisting clinical symptoms and spontaneous closure of FTMH, BCVA, and spectral domain optical coherence tomography (SD-OCT) of vitreomacular interface. In a follow-up period, all eyes showed closure of FTMH (closure range: 3-64 weeks). The "bridging" phenomenon was a main mechanism of a spontaneous FMTH closure. Additionally, posterior vitreous detachment with the release of vitreomacular traction was observed in 4 eyes (40%). The statistical analysis showed that shorter the duration of symptoms, shorter the duration of the spontaneous FTMH closure (r = 0 673, P < 0 05). No significant association was observed between the time of spontaneous closure FTMH, the age of patients, and BCVA. The regeneration of the outer nuclear layer (ONL) and external limiting membrane (ELM) was confirmed in 10 and 9 eyes, respectively. In six eyes, connections between inner and outer segments of photoreceptors were rebuilt; in these cases, the final BCVA was the best. None of the eyes showed the regeneration of the connections between the outer segments of photoreceptor and retinal pigment epithelium (RPE). The main mechanism leading to a spontaneous closure of FTMH is the "bridging" phenomenon. Vitreous detachment and vitreomacular traction release are not necessary conditions promoting the closure of FTMH. Shorter duration of symptoms and regeneration of photoreceptors IS/OS interface provide a better final BCVA.

Dynamic modelling of strategies for the control of acute haemorrhagic conjunctivitis outbreaks in schools in Changsha, China (2004-2015).

Outbreaks of acute haemorrhagic conjunctivitis (AHC) - a rapidly progressing and highly contagious infection - often occur in schools during summer and autumn. We used dynamic modelling to evaluate the efficacy of interventions to control AHC outbreaks in schools. A susceptible-infected-recovered (SIR) model was built to simulate AHC outbreaks in Chinese schools, with isolation or school closure added into the model. We used outbreak data from the period 2004-2015 in our models to estimate the effective reproduction number and assess the efficacy of interventions. The median effective reproduction number (uncontrolled) of AHC outbreaks was 7·00 (range 1·77-25·87). The median effective reproduction number (controlled) of AHC outbreaks was 0·16 (range 0·00-2·28). Intervention efficacy is affected by the timing of isolation; earlier isolation is associated with a lower morbidity peak and smaller total attack rate (TAR). School closures were not effective; TARs were almost 100% and did not change even when different school closure durations were adopted. Isolation and school closure as a combined intervention strategy was used to simulate outbreak control, but the efficacy was the same as isolation alone. An isolation programme could be an effective primary intervention during AHC outbreaks in schools. However, school closure is not recommended.

The Effects of Humming on the Prephonatory Vocal Fold Motions Under High-Speed Digital Imaging in Nondysphonic Speakers

This study aimed to investigate whether humming affects the adductive motion of the vocal folds and transient glottal closure in the prephonatory adjustment phase of vocal onset using high-speed digital imaging (HSDI) and a motion analysis software program. Twenty normal healthy adults without any vocal abnormalities were enrolled. While a transnasal flexible fiberscope connected to a high-speed camera was inserted, each participant was asked to perform three phonatory tasks-natural /e:/ phonation, loud /e:/ phonation, and humming /m:/ phonation-and laryngeal HSDI movies (4000 frame/s) were recorded. On each HSDI movie, the duration of the prephonatory glottal closure was measured. In addition, using motion analysis, the changes in the angle between the bilateral vocal folds during vocal fold adduction and the average angular velocity in the ranges of 100%-80%, 80%-20%, and 20%-0% from all of the angular changes were analyzed. The angular changes showed sigmoid and polynomial-like curves during the natural/humming and loud phonation, respectively, and the 80%-20% and 20%-0% average velocities were the highest during the natural/humming and loud phonation, respectively. The humming phonation decreased all of the average regional velocities, eliminated the transient prephonatory glottal closures observed during the natural and loud phonation, and induced a greater value for the minimal angle than the natural phonation. The present study demonstrates that humming encourages easy vocal initiation by decelerating the vocal fold adductive motion throughout the prephonatory adjustment phase and alleviating transient prephonatory laryngeal closure, leading to gradual and smooth vocal fold positioning.