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Most studies investigating the effect of sex hormones on the larynx and vocal folds focused on the voice quality of women either around menopause or during the menstrual cycle. To our knowledge, however, there have been no studies that investigated the effect of oral contraceptives on the female voice. In the present study five women who ingest oral contraceptives (pill group) and five women who do not (natural group) were recorded producing the vowels /i/ and /a/ repeatedly over a period of 40 days. Acoustic analyses were performed on these recordings including F0, amplitude, jitter, shimmer, and harmonic-to-noise ratio (HNR). Results indicated that jitter and shimmer values of the pill group were significantly lower than those of the natural group. No group differences were found for F0, amplitude, or HNR. In addition, the pill group demonstrated significantly smaller variance for all variables tested. The results suggest that oral contraceptives might increase voice stability associated with smaller hormonal changes. Thus the present study provides preliminary evidence of the effect of oral contraceptives on the female voice. 相似文献
22.
Virginia Wolfe PhD Joanne Long Heather Conner Youngblood Henry Williford Michelle Scharff Olson 《Journal of voice》2002,16(1):52-60
Aerobic instructors frequently experience vocal fatigue and are at risk for the development of vocal fold pathology. Six female aerobic instructors, three with self-reported voice problems and three without, served as subjects. Measures of vocal function (perturbation and EGG) were obtained before and after a 30-minute exercise session. Results showed that the group with self-reported voice problems had greater amounts of jitter, lower harmonic-to-noise ratios, and less periodicity in sustained vowels overall, but no significant differences in measures of perturbation and EGG were found before and immediately after instruction. Measures of vocal parameters showed that subjects with self-reported voice problems projected with relatively greater vocal intensity and phonated for a greater percentage of time across beginning, middle, and ending periods of aerobic instruction than subjects with no reported voice problems. 相似文献
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This paper is devoted to the study of periodic solutions for a class of second-order ordinary differential equations by utilizing a technique for obtaining solutions to free problems in the calculus of variations originating in the work of Carathéodory (Ref. 1, 1935). The key of this technique is to find some suitable transformation which transfers the periodic solution problem to an equivalent variational problem in which the minimizer is more easily determined. Some applications are presented to illustrate the utility of this technique.Supported by NSFC Grant 10401013, 985 Project of Jilin University and Graduate Innovation Lab of Jilin University. The authors thank Professor D. A. Carlson and the anonymous referees for valuable suggestions and helpful comments. 相似文献
25.
Audio recordings were made while six vocally untrained individuals read sentences aloud after breathing to three different lung volume levels-typical, high, and low. A perceptual experiment was conducted on these speech samples. The perceptual experiment consisted of a two-alternative forced-choice design, in which listeners heard matched pairs of sentences and were asked to identify which sentence in the pair departed from normal sounding speech. The results of the perceptual experiment showed that listeners can accurately discriminate between speech produced at both lung volume extremes. The percentage of correct identification was higher for speech produced at low lung volumes than that for high lung volumes. Factors such as order of presentation and removal of SPL as an acoustic cue made little difference in the ability of listeners to discriminate lung volume level from the speech signals. 相似文献
26.
Histologic and Rheologic Characterization of Vocal Fold Scarring 总被引:2,自引:0,他引:2
Susan L. Thibeault PhD Steven D. Gray Diane M. Bless Roger W. Chan Charles N. Ford 《Journal of voice》2002,16(1):96-104
Scarring of the vocal fold causes considerable dysphonia and presents significant treatment challenges. A rabbit model was developed to investigate the histologic ultrastructure and rheologic properties of the scarred vocal fold lamina propria. Eleven rabbit larynges were scarred by means of forcep biopsy. Sixty days postoperatively, the rabbits were sacrificed and their vocal folds were harvested. Histological analysis of the scarred and normal lamina propria was completed for collagen, procollagen, elastin, and hyaluronic acid. Linear viscoelastic shear properties of the tissues were also measured, including elastic shear modulus and dynamic viscosity. Compared to normal vocal fold lamina propria, scarred tissues demonstrated significantly less collagen, an increase in procollagen, and a decrease in elastin. Rheologically, both elastic shear modulus and dynamic viscosity were significantly higher for the scarred tissues. Increased stiffness and viscosity do not appear to result from an increase in collagen, but rather appear to be related to the presence of new, disorganized collagen scaffolding. Results are interpreted in terms of the possible role of interstitial proteins in the etiology of increased stiffness and viscosity, which requires further investigation. This animal model should allow for systematic future investigations of vocal fold scarring and its treatment. 相似文献
27.
Anne-Maria Laukkanen PhD Raija Takalo Miika Arvonen Erkki Vilkman 《Journal of voice》2002,16(2):182-194
Pitch-synchronous changes in the anterior cricothyroid (CT) space were registered with ultrasonography (USG) for ten healthy subjects (5 males, 5 females) during the production of musical fifths throughout the whole voice range. One of the males and one of the females were trained amateur singers, the other subjects were choir singers. The average decrease in CT space per a musical fifth was 1.3-2.4 mm for the males and 1.0-1.8 mm for the females; the average decrease was smaller in the middle of the pitch range for both genders. The results suggest that (1) USG can be used for detection of pitch-synchronous changes in the CT space; (2) these changes are dependent on pitch range; and (3) more trained singers tend to have somewhat smaller changes than less trained subjects at certain frequencies. The results seem to indicate that F0 control mechanism varies according to pitch range and register, and possibly according to individual structure and vocal technique related differences. 相似文献
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Andrea R. Milner PhD 《School science and mathematics》2012,112(5):267-269
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Cartography is the art of map‐making that integrates science, technology, and visual aesthetics for the purpose of rendering the domain of interest, navigable. The science could aid the cartographer if it were to inform about the underlying process. Thus, Mendeleev's periodic table was informed by insights about the atomic mass periodicity. Likewise, Harvey's work on the circulatory system map was informed by his theoretical insights on Galen's errors. Mapping of human knowledge dates back at least to Porphyry who laid out the first tree‐of‐knowledge. Modern knowledge‐cartographers use a wide array of scientometric techniques capable of rendering appealing visuals of massive scientific corpuses. But what has perhaps been lacking is a sound theoretical basis for rendering legible the adaptive dynamics of knowledge creation and accumulation. Proposed is a theoretical framework, knowledge as a complex adaptive system (CAS) patterned on Holland's work on CAS, as well as the view that knowledge is a hierarchically heterarchic dynamical system. As a first leg in the conjoining experimental phase, we extract terms from approximately 1400 complexity science papers published at the Santa Fe Institute, deduce the topic distribution using Latent Dirichlet Allocation, capture the underlying dynamics, and show how to navigate the corpus visually. © 2016 Wiley Periodicals, Inc. Complexity 21: 207–234, 2016 相似文献
30.
A discrete spectra transformation technique is used for the processing and analysis of long-term stress relaxation and creep compliance data of mineral-filled polymer composites. A non-linear regression simultaneously adjusts the parameters of N discrete relaxation or retardation spectra. For small N the solution is insensitive to the choice of regression starting value sets. From the relaxation time spectrum a corresponding discrete retardation spectrum and creep compliance can be calculated using the Laplace transform and vice versa. The analysis of long-term (more than 1200 days) both relaxation and retardation experimental data demonstrates the applicability of the transformation technique. Comparisons of the experimental and calculated spectra are given. The influence of the filler amount is demonstrated. 相似文献