The purpose of the current study was to determine how maximum phonation duration (MPD) of five notes (C4, D4, E4, F4, G4) sustained on /o/, sustained vowels (/i/, /ae/, /a/, /u/), and s/z ratio (sustained /s/ and /z/) changed during voice therapy for vocal nodules. Voices of adult females before ...

A promising countermeasure for fatigue in sustained aviation operations is stimulant administration. However, well-controlled, aviation-relevant studies of the efficacy of medications such as Dexedrine are virtually nonexistent. In this investigation, flight performance, mood, and alertness were evaluated in 10 UH-60 pilots during sleep deprivation periods under Dexedrine or placebo. Relative ...

In concurrent-chains schedules, pigeons prefer terminal links that provide two keys correlated with reinforcers (free choice) over those that provide only one key (forced choice), terminal-link reinforcement rates being equal. With same-size keys, free choice provides a larger area available for pecking. Preferences were examined using terminal links that differed ...

Adaptation to bed rest or space flight is accompanied by an impaired ability to exercise in an upright position. We hypothesized that a daily, 30-min bout of intense, interval exercise in upright posture or supine against lower body negative pressure (LBNP) would maintain upright exercise heart rate and respiratory responses ...

The studies were conducted on the transmeridian routes Düsseldorf (DUS)-Atlanta (ATL) and Hamburg (HAM)-Los Angeles (LAX), and on the north-south route Frankfurt (FRA)-Mahe (SEZ). Scheduled flight duration was between 8:50 hours (ATL-DUS) and 11:50 hours (HAM-LAX). In total, 25 rotations (50 flights) have been investigated by pre-, in- and post-flight ...

INTRODUCTION: Recently, a visually driven neck reflex was identified as causing head tilt toward the horizon during VMC flight. If this is the case, then pilots orient about a fixed rather than moving horizon, implying current attitude instruments inaccurately present spatial information. The purpose of this study was to determine ...

Currently, early phonatory changes in amyotrophic lateral sclerosis (ALS) are not well understood. The aim of this study was to compare acoustic parameters of voice in ALS subjects who demonstrated perceptually normal vocal quality on sustained phonation with a control group. We hypothesized that objective analysis of voice would reveal ...

I review the relative importance of internal and external sources of prebiotic molecules on Earth at the time of life's origin approximately 3.7 Gyr ago. The efficiency of synthesis in the Earth's atmosphere was critically dependent on its oxidation state. If the early atmosphere was non-reducing and CO2-dominated, external delivery ...

The present study addresses two questions: (a) Is the action and/or posture of the velopharyngeal valve conducive to allow significant resonance during Western tradition classical singing? (b) How do the actions of the velopharyngeal valve observed in this style of singing compare with normal speech? A photodetector system was used ...

The physiological aim of vocal exercises is mostly understood in intuitive terms only. This article presents an attempt to document the phonatory behavior induced by a vocal exercise. An elevated vertical position of the larynx is frequently associated with hyperfunctional phonatory habits, presumably because it induces an exaggerated vocal fold ...

How does a hovering hummingbird compensate for the loss of flight feathers during moult when the mechanism of lift force generation by flapping wings is impaired? The flight performance of five individual ruby-throated hummingbirds with moulting primary flight feathers and reduced wing area was compared with that before their moult. ...

The present study investigated the effect of reinforcer duration on running and on responding reinforced by the opportunity to run. Eleven male Wistar rats responded on levers for the opportunity to run in a running wheel. Opportunities to run were programmed to occur on a tandem fixed-ratio 1 variable-interval 30-s ...

As the power source for vocalization, the lower respiratory tract plays a key role in voice production. This is particularly true with sustained singing, where continued high ventilatory demands are present. Changes in pulmonary function that are insignificant with normal speech have been shown to lead to performance impairment. The ...

This article presents selected findings obtained with Holter monitoring from two crew members of the expedition, performed during a 175-day space mission on board orbital space station "MIR." Using mathematical processing of daily cardiointervals files, 5-minute sections of records were analyzed consecutively. Then, the average daily values of indices, the ...

BACKGROUND: The microgravity environment of spaceflights alters the systemic circulation, decreasing the peripheral resistance, while increasing the heart rate and systemic blood pressure. HYPOTHESIS: Body orientation simulating fluid shifts associated with microgravity during spaceflights affects the neural retinal function. METHODS: Fifteen healthy adults between 18 and 26 yr of age ...

A Research Roundtable, organized by the American College of Sports Medicine with sponsorship from the National Aeronautics and Space Administration, met in November 1995 to define research strategies for effective exercise countermeasures to weightlessness. Exercise was considered both independently of, and in conjunction with, other therapeutic modalities (e.g., pharmacological nutritional, ...

BACKGROUND: Interpersonal problems may negatively affect crews on long-duration space missions. These problems stem from crewmember tension and its displacement to the outside monitoring personnel and from disruptions in crew cohesion and unclear leadership roles. HYPOTHESES: We hypothesized that crew tension and dysphoria would transiently increase following stressful events and ...

Hovering hummingbirds offer a model locomotor system for which analyses of both metabolism and flight mechanics are experimentally tractable. Because hummingbirds exhibit the highest mass-specific metabolic rates among vertebrates, maximum performance of hovering flight represents the upper limit of aerobic locomotion in vertebrates. This study evaluates the potential constraints of ...

The mucosal upheaval where the mucosal wave starts and propagates upward appears on the lower surface of the canine vocal fold during vibration. We investigated the vibratory behavior of the in vivo human vocal fold viewed from the tracheal side. Subjects consisted of 14 men and 6 women who had ...

1. Studies show that reversible inactivation of the anterior interpositus nucleus (AIP) of the cerebellum with muscimol (a GABAA agonist) prevents acquisition of the classically conditioned nictitating membrane response (NMR) in the rabbit. Here, we have used reversible inactivations of the AIP with muscimol to investigate the role of the ...

Despite the fact that the first human was in space during 1961 and individuals have existed in a microgravity environment for more than a year, there are limited spaceflight data available on the responses of the neuroendocrine and immune systems. Because of mutual interactions between these respective integrative systems, it ...

Exercise represents the primary countermeasure used during spaceflight to maintain or restore maximal aerobic capacity (VO2max), musculoskeletal structure, and orthostatic function. However, no single exercise or combination of prescriptions has proven entirely effective in restoring cardiovascular and musculoskeletal functions to preflight levels following prolonged spaceflight. As human spaceflight exposures increase ...

Since 1961, there have been more than 165 flights involving several hundred individuals who have remained in a space environment from 15 min to more than a year. In addition, plans exist for humans to explore, colonize, and remain in microgravity for 1000 d or more. This symposium will address ...

The repeated association during the late Neoproterozoic Era of large carbon-isotopic excursions, continental glaciation, and stratigraphically anomalous carbonate precipitation provides a framework for interpreting the reprise of these conditions on the Late Permian Earth. A paleoceanographic model that was developed to explain these stratigraphically linked phenomena suggests that the overturn ...

In this technical article, methods for collecting and representing response rates maintained by schedules of reinforcement are presented. First, the time in a session that each important event (e.g., responses, reinforcers) occurs is collected and stored by a computer. Another computer program is used, then, to convert each response to ...

Cardiac output (Q), heart rate (HR), blood pressure, and oxygen consumption (VO2) were measured repeatedly both at rest and at two levels of exercise in six subjects during microgravity exposure. Exercise was at 30 and 60% of the workload producing the individual's maximal VO2 in 1 G. Three of the ...

Respiratory and glottal efficiency measures were collected from a pool of 40 classically trained singers with normal larynges. All singers had > or = 3 years of formal classical voice training and were active professional solo classical singers. Mean flow rates were obtained from all subjects to assess glottal efficiency. ...

Insect flight is the most energy-demanding exercise known. It requires very effective coupling of adenosine triphosphate (ATP) hydrolysis and regeneration in the working flight muscles. 31P nuclear magnetic resonance (NMR) spectroscopy of locust flight muscle in vivo has shown that flight causes only a small decrease in the content of ...

BACKGROUND: Evidence in support of the sensory conflict hypothesis for space motion sickness (SMS) is still needed. HYPOTHESIS: We hypothesized that sensory conflict and recovery processes should be demonstrated in intact fish during initial days of microgravity exposure, as a disturbance and restoration of the dorsal light response (DLR; a ...

The voiced bilabial fricative/beta:/has been used as a vocal exercise. The present study investigated the effects of the exercise on voice production and voice source. This study compared vowel phonation on the syllable /a:p/ with the production of the exercise and vowel phonation before and immediately after the exercise. The ...

In the functional analysis described by Iwata, Dorsey, Slifer, Bauman, and Richman (1982/1994), reinforcer duration varied across conditions (e.g., brief attention vs. 30 s of escape); this may result in unequal exposure to the establishing operations for aberrant behavior. In this study, we compared the effects of unequal and equal ...

The necessity of preventing physiologic deconditioning of astronauts exposed to long duration space flights is well known. A method under consideration to prevent this deconditioning is the use of periodic exposure to artificial gravity which could be provided by a centrifuge. This paper presents a design study for a human-powered ...

To assess a possible otolith contribution to effects observed following prolonged exposure to hypergravity, we used video oculography to measure ocular torsion during static and dynamic conditions of lateral body tilt (roll) before and after 1 h of centrifugation with a Gx-load of 3 G. Static tilt (from 0 to ...

Two species of newts (Urodela) and two types of clinostats for fast clinorotation (60 rpm) were used to investigate the influence of simulated weightlessness on regeneration and to compare results obtained with data from spaceflight experiments. Seven or fourteen days of weightlessness in Russian biosatellites caused acceleration of lens and ...

This study presents qualitative and quantitative data concerning gravity-dependent changes in the swimming behaviour of developing cichlid fish larvae (Oreochromis mossambicus) after a 9 resp. 10 days exposure to increased acceleration (centrifuge experiments), to reduced gravity (fast-rotating clinostat), changed accelerations (parabolic aircraft flights) and to near weightlessness (2nd German Spacelab ...

The archaic eukaryote unicellular microorganism, Paramecium, is propelled by thousands of cilia, which are regulated by modulation of the membrane potential. Ciliates can successfully cope with gravity, which is the phylogenetically oldest stimulus for living things. One mechanism for overcoming sedimentation is negative gravitaxis, an orientational response antiparallel to the ...

The demands of dynamic monitoring and fault diagnosis for flight engineer trainees were examined in relation to changes in heart rate (HR) and two spectral analysis measures (midfrequency: 0.07-0.14 Hz; high frequency: 0.15-0.40 Hz) of heart rate variability (HRV). Eleven trainee flight engineers were studied, as part of their training ...

INTRODUCTION: Optimum treatment for aircrew who have developed anxiety associated with flight includes a flying phase for desensitization. However, standardized flight profiles are not found in the literature. In this study, a method of desensitization flying, which may increase the probability of a return to productive flying, was devised and ...

Zero gravity conditions for astronaut training have traditionally used neutral buoyancy tanks, and with such tanks hypogravity conditions are produced by the use of supplemental weights. This technique does not allow for the influence of water viscosity on any reduced gravity exercise regime. With a water-foam fluid produced by using ...

The system of countermeasure of microgravity effects has been developed in Russia that allowed to perform safely long-term space flights. This system that includes different means and methods such as special regimens of physical exercises, axial loading ("Pingiun") and antigravity suits, low body negative pressure device (LBNP, "Chibis") and "cuffs" ...

This study was performed to determine the effects of 28 d of head-down tilt (HDT) (simulated weightlessness) on cardiovascular responses to orthostatic stress induced by lower body negative pressure (LBNP) (before, during, and after HDT) and +60 degrees head-up tilt (before and after HDT) in 12 subjects. Half of them ...

With reinforcement contingent on a single peck on either of two available keys (concurrent continuous reinforcement schedules) 4 pigeons, at 80% of free-feeding weights, preferred a smaller-sooner reinforcer (2.5 s of mixed grain preceded by a 0.5-s delay) to a larger-later reinforcer (4.5 s of mixed grain preceded by a ...

This study examined changes in voice and speech production in a patient with Parkinson disease as he increased vocal intensity following 1 month of intensive voice treatment. Phonatory function and articulatory acoustic measures were made before and after treatment as well as 6 and 12 months later. Pre- to post-treatment ...

Seventeen healthy women, 45 to 61 years old, were examined using videofiberstroboscopy during phonation at three loudness levels. Two phoniatricians evaluated glottal closure using category and ratio scales. Transglottal airflow was studied by inverse filtering of the oral airflow signal recorded in a flow mask (Glottal Enterprises System) during the ...

The purpose of this single-subject pilot study was to examine the efficacy of FM amplification for enhancing the discourse skills of a 4-year-old girl with a history of speech-language impairments, otitis media with effusion (OME), and motoric delays. Over a period of several weeks, language treatment sessions were conducted with ...

Today's battleground requires round-the-clock air support. Modern aircraft systems enable tactical aircraft to be flown in all weather conditions, day or night, and for prolonged periods. U.S. Air Force Tactical Air Command (TAC) aircrew who deployed to the Southwest Asia Area of Responsibility (SWA AOR) for Operation Desert Shield/Desert Storm ...

The purpose of this study was to develop a definition of the supported singing voice based on physiological characteristics by comparing the subjects' concepts of a supported voice with objective measurements of their supported and unsupported voice. This preliminary report presents findings based on data from eight classically trained singers. ...

The purpose of this study was to investigate the effects of isometric-isotonic vocal function exercises, practiced regularly for 4 weeks, on parameters of voice production in the healthy singer. A total of 20 university graduate-level voice majors of similar age and vocal training were divided into experimental and control groups, ...

The glottal resistance, i.e. the ratio of subglottic pressure to glottal flow, and the laryngeal efficiency, i.e. the ratio of oral acoustic power to aerodynamic subglottal power (multiplication of subglottig pressure and glottal flow), were measured for 11 subjects (3 males) with normal voices and for 1 female patient with ...

Measurements from mission specialists after space flights or from subjects subjected to head down tilt experiments have demonstrated a decrease in exercise performance. Similar decreases have been reported for rats that have participated in simulated microgravity studies using the head down-tail suspended method of Morey-Holton (HDS). Because it is unclear ...