Measurement of Characteristic Leap Interval Between Chest and Falsetto Registers

A markedly smaller time constant distinguishes a chest-falsetto leap from the more usual execution of a sung interval by muscular adjustments in the length and tension of the vocal folds. The features of such a chest-falsetto leap are examined in detail with respect to F0, peak-to-peak amplitude of the vocal-fold contact area signal (EGG), and the closed quotient. A method is proposed to standardize and quantify this chest-falsetto leap in the characteristic leap interval (CLI), a measure of the separation between the natural registers in a given singing voice. The measure is applied to a varied group of experienced singers. Preliminary results include a suggested dimorphic pattern with respect to sex, with female voices exhibiting smaller CLIs and less individual diversity than male voices.     

Influence of Freezing and Low Molecular Weight Cryoprotectants on Microsomal Membrane Structure: A Study by Multiparametric Fluorescent Probe

The influence of low molecular weight cryoprotectants (CPs) such as glycerol (GL), 1,2-propanediol (PD) and dimethylsulfoxide (DMSO) on the structure of rat liver microsomal membranes on the stages of equilibration and upon freezing up to −196°C was studied using a multiparametric fluorescent probe of flavonol nature. It was estimated that the studied CPs have individual concentration ranges defining low amplitude of their action on biomembranes. An exceeding of these ranges strongly increases the violation of membrane native structure already at the stage of incubation with CPs, strengthening it during the freezing procedure. According to the perturbation effect on microsomal membranes the studied CPs can be arranged in a sequence: DMSO > PD > GL.     

Objective Voice Analysis for Dysphonic Patients: A Multiparametric Protocol Including Acoustic and Aerodynamic Measurements

The purpose was to determine the clinical value of a multiparametric objective voice evaluation protocol including acoustic and aerodynamic parameters measured mainly on a sustained /a/. This was done by comparison with perceptual analysis of continuous speech by a jury composed of 6 experienced listeners. Voice samples (continuous speech) from 63 male patients with dysphonia and 21 control subjects with normal voices were recorded and assesed by a jury of listeners. The jury was instructed to classify voice samples according to the G (overall dysphonia) component of the GRBAS score on a 4-point scale ranging from 0 for normal to 3 for severe dysphonia. Objective parameters were recorded on an EVA^® workstation. As usual with this type of system, parameters were measured mainly on a sustained /a/. Measured parameters included fundamental frequency (F₀), intensity, jitter, shimmer, signal-to-noise ratio, Lyapunov coefficient (LC), oral airflow (OAF), maximum phonatory time (MPT), and vocal range (range). Estimated subglottic pressure (ESGP) was determined on a series of /pa/. Discriminant analysis was performed to detect correlation between jury classification and combinations of parameters. Results showed that a nonlinear combination of only six parameters (range, LC, ESGP, MPT, signal-to-noise ratio, and F₀) allowed 86% concordance with jury classification. Discussion deals with the relative importance of the different objective parameters for discriminant analysis. Special emphasis is placed on two measurements rarely made in routine clinical workup, i.e., estimated subglottic pressure and Lyapunov coefficient.     

A Preliminary Study of Vocal Health Among Collegiate A Cappella Singers

ObjectiveCollegiate a cappella groups have grown significantly in popularity and prominence; however, there have been few studies that evaluate the vocal health of this subgroup of young singers. The objective of this preliminary study was to conduct a multiparametric evaluation of the vocal health characteristics of a sample of collegiate a cappella singers. We further tested whether differences in vocal health assessments exist between a cappella singers with and without vocal training and trained collegiate singers who do not participate in a cappella groups.Study designPoint prevalence study.MethodsForty-one collegiate singers participated in this study. Participants were divided into the following three groups: trained singers (TS), trained a cappella singers (ATS), and untrained a cappella singers (AUS). Participants were administered a set of surveys to assess self-perception of singing voice health and perceived access and attitudes toward voice-related health care. Acoustic and laryngoscopic assessments of participant's speaking and singing voice was performed and validated vocal health questionnaires administered as a means to objectively evaluate for the presence of voice problems.ResultsOverall, 87.5% of the ATS and 60% of the AUS groups reported experiencing problems with their singing voice. However, no vocal abnormalities were detected during laryngoscopic and acoustic assessments. Furthermore, minimal differences between any of the measured vocal health parameters were observed between the TS, ATS, and AUS groups.ConclusionCollectively, a high percentage of collegiate a cappella singers with and without vocal training report singing voice problems. However, our sample of a cappella singers did not have increased singing voice problems as compared to vocally trained collegiate singers not in a cappella groups. We did find that a cappella singers may be more inclined to seek information about maintaining a healthy singing voice from their fellow musicians as opposed to singing teachers or other voice health professionals. Singing teachers, otolaryngologists, and speech-language pathologists may need to play a more active role in educating a cappella singers regarding maintaining good vocal health.     

Sex Differences in Physical Activity in People After Stroke: A Cross-sectional Study

OBJECTIVE: Adequate physical activity after stroke is critical for cardiovascular health. Although sex is a potential factor associated with post-stroke physical activity, its mechanism remains unclear. This study aimed to examine sex differences in human physical activity following stroke. METHOD: A cross-sectional study with 62 participants (men: 42, women: 20) was conducted. Physical activity was measured for three consecutive days using a step activity monitor. The walking durations per day in light physical activity, moderate-to-vigorous physical activity, and total physical activity were calculated. Sex differences in walking duration were compared using Welch''s t-tests or Mann-Whitney U tests. RESULTS: Women had a significantly greater walking duration in light physical activity and in total than did the men. In contrast, no significant differences were found in moderate-to-vigorous physical activity. CONCLUSION: This study reported sex differences in the walking duration after stroke. Moreover, it found that women spent more time in low intensity physical activity than men. Our results will be useful for planning interventions to increase physical activity and decrease sedentary behavior after stroke.     

Multicarrier Transport: Batteries, Semiconductors, Mixed Ionic-Electronic Conductors, and Biology

Multicarrier systems, such as car batteries and semiconductors, have surprisingly complex transport properties. Even for steady-state transport, one can find counterexamples to standard assumptions about local electroneutrality, constancy in space of the electric field, linearity in space of the voltage, and the relationship between dissipation, voltage, and current. Moreover, unless recombination processes occur, boundaries impose conditions that can disturb the response far into the bulk to remove memory of the boundaries. Because the demands of the chemical reactions at the electrodes cannot be satisfied by diffusion alone, car batteries are electrically active even when they are neither charging nor discharging. We offer practical advice on battery care for bike-riders, say, who only occasionally use their cars. For semiconductors, recombination does occur, which in transport enables partial currents to adjust from their surface to their bulk values. For mixed ionic electronic conductors, bulk recombination may be essential to an understanding of blocking electrodes. The voltage associated with both current-producing and non-current-producing surface reactions provides a natural explanation for the bioelectric fields observed during root and other growth processes.     

A Correlation Among Orthogonality Relation,Variational Principle and Perturbation Theory

It is observed that variationally calculated wavefunctions do not satisfy orthogonality relation when tested for the potentials like anharmonic oscillator and deviated hydrogen atom type. A new approach is suggested using quasi-states only to correlate between variationally calculated wavefunctions and orthogonality relation using perturbation theory considering the anharmonic oscillator example. Analytically expression for energy levels of the anharmonic oscillator are calculated up to the second order. A test for convergency of the perturbation theory is also discussed.     

The Prevalence of Voice Disorders Among Day Care Center Teachers Compared with Nurses: A Questionnaire and Clinical Study

The acceptance of voice disorders by day care center teachers as an occupational disease is not an invariably established practice. This is due to the lack of reliable evidence of a higher risk for voice disorders in this profession. To find out the risk of voice disorders, an epidemiological study was conducted among day care center teachers (n = 262), using hospital nurses (n = 108) as a control group. Symptoms were charted by a questionnaire. In a clinical examination made by a laryngologist, the voice quality was assessed and the laryngeal status noted. Teachers at day care centers had significantly more voice disorders than did nurses. Vocal nodules and laryngitis findings appeared significantly more frequently among day care center teachers than among those in the control group. The results prove voice disorders to be more frequent among day care center teachers than among control group subjects, and also that the main cause for this may be a higher vocal loading among day care center teachers than among control group subjects.     

A Theoretical Study of Pure and Mixed Spin-Polarized Tritium and Helium Triatomic Systems Using Hyperspherical Coordinates

Pure and mixed spin-polarized tritium ( ${{\rm T}\uparrow}$ ) and helium (He) triatomic systems are studied using hyperspherical coordinates. A slow variable discretization approach is adopted to solve the nuclear Schrödinger equation, in which the Schrödinger equation in hyperangular coordinates is solved using basis splines at a series of fixed FEM-DVR hyperradii. By using the best empirical interaction potentials, we study comparatively the bound states of ( ${{\rm T}\uparrow}$ )₃, ⁴He( ${{\rm T}\uparrow}$ )₂, ${^4{\rm He}_2{\rm T}\uparrow}$ , ⁴He₃ and ${^4{\rm He}_2^3{\rm He}}$ in the J ^Π = 0⁺ symmetry. The bound state energy levels are calculated for all these molecular species except ⁴He( ${{\rm T}\uparrow}$ )₂, for which we have found no bound state. The calculated wave functions of these species are found all to exhibit a very large spatial extension, indicating the diffuse nature of these bound states. The molecular structure of these species will also be calculated and analyzed in detail.     

Mixed 2D molecular systems: Mechanic, thermodynamic and dielectric properties

Study of Langmuir monolayers consisting of stearic acid (SA) and dipalmitoylphosphatidylcholine (DPPC) molecules was done by surface pressure-area isotherms (π-A), the Maxwell displacement current (MDC) measurement, X-ray reflectivity (XRR) and atomic force microscopy (AFM) to investigate the selected mechanic, thermodynamic and dielectric properties based on orientational structure of monolayers. On the base of π-A isotherms analysis we explain the creation of stable structures and found optimal monolayer composition. The dielectric properties represented by MDC generated monolayers were analyzed in terms of excess dipole moment, proposing the effect of dipole-dipole interaction. XRR and AFM results illustrate deposited film structure and molecular ordering.     

Mixed hyperfine interactions in amorphous materials: A model study

⁵⁷Fe Mössbauer absorption profiles were calculated supposing distributions of all hyperfine parameters: hyperfine magnetic fields, isomer shifts, and electric field gradients. The effect of mixed hyperfine interactions was taken into account in all orders of perturbation theory. The shapes of the spectra were systematically studied for varying average values and widths of the hyperfine magnetic field distribution (HMFD). From the simulated spectra, the shapes of the HMFD were reconstructed using standard techniques of Mössbauer spectra processing which neglect the effects of random isomer shifts and electric field gradients. It has been shown that the reconstructed shapes of the HMFD differ qualitatively from the original single-peaked distributions and exhibit a double-peaked structure similar to the distributions found in many experiments on amorphous alloys with low iron content. A brief review of various mechanisms responsible for either apparent or real double-peaked structure of HMFD has been given.     

A Two-Dimensional Relaxation Study of the Evolving Microstructure in a Mixed Biopolymer Gel

It is shown that two-dimensional (2-D) T ₁–T ₂ relaxation spectra are sensitive to the changing microstructure in a model food system comprising water-in-water gelatin–agarose gelled emulsions. This 2-D relaxation–microstructure relationship suggests that T ₁–T ₂ spectra have the potential of acting as “fingerprint” molecular biomarkers of microstructure in complex water-rich biological systems and this has important future implications for in vivo magnetic resonance imaging studies of food digestion and of the changing structure of cancerous tissue.     

Epidemiological Study of Voice Disorders Among Teaching Professionals of La Rioja, Spain

The purpose of the present study was to calculate the prevalence and incidence of voice disorders among teaching staff and find out the associated occupational risk factors. A case-control study was performed with 905 teachers, 579 cases and 326 controls; 492 were randomly selected and 413 volunteered. All teachers were asked to fill out a standard questionnaire. Next, a complete laryngeal exam was performed including a general ear, nose, and throat evaluation and videolaryngostroboscopy. The prevalence of voice disorders among teaching staff was 57%. The most prevalent lesions were vocal overstrain (18%), nodular lesions (14%), and hyperfunctional dysphonia (8%). The incidence rate was 3.87 new cases per year per 1000 teachers. Women had organic lesions three times more than men (odds ratio [OR]: 3.52, confidence interval [CI]: 2.04-6.09). However, men had chronic laryngitis three times more than women (OR: 2.93, CI: 1.50-5.71) and functional dysphonia nearly twice more than women (OR: 1.81, CI: 1.21-2.69). We find a significant risk of suffering voice disorders in teachers who smoke daily (OR: 2.31, CI: 1.58-3.37) and who drink several cups of coffee or tea (OR: 1.87, CI: 1.36-2.56). It is advisable to carry out an annual evaluation of all teaching staff on account of the high prevalence of voice disorders among them.     

玉米自交系籽粒的遗传距离与其近红外光谱距离和品种鉴别模型性能的关系研究

从玉米自交系种子的遗传距离、近红外光谱距离、品种鉴别模型性能三方面进行分析,探索三者间的关系。采用三组(共15对)遗传关系远近不同的玉米自交系种子作为实验材料,通过简单重复序列(simple sequence repeats, SSR)标记计算自交系种子间的遗传距离;种子的近红外光谱经预处理后降维到主成分分析(principal component analysis, PCA)空间中,计算各个自交系种子样本中心点之间的欧氏距离,作为对应的近红外光谱距离;使用仿生模式识别方法建立鉴别模型,用模型的鉴别正确率评价模型的性能。分析结果表明,自交系种子间遗传距离与近红外光谱距离相关性为0.986 8,与模型鉴别正确率的相关性为0.911 0,相关性显著。说明近红外光谱可以反映出玉米自交系种子之间的遗传关系,遗传关系的远近影响品种鉴别模型的性能,遗传距离越小,近红外光谱距离越小,模型鉴别能力也越差。实际应用中有望利用近红外光谱技术分析玉米自交系的遗传关系,对遗传育种、品种识别、纯度分选等具有重要意义;且建立品种鉴别模型时,应充分考虑遗传关系较近的玉米自交系对模型性能的影响。