Effects of Testosterone Replacement on a Male Professional Singer

Testosterone has been known to play an important role in the development of the postpubertal male voice for many centuries. In fact, the prevention of pubertal development of the voice by castrating young male singers was a well-known practice, especially in Italy beginning in the sixteenth century. The “castrati” were well known for their clear, high-pitched voices. Because of the resulting small larynx and vocal folds, castrati apparently produced a distinctive resonance as well as the high pitch, which cannot be matched even by the counter tenors of today. Busy voice labs occasionally see males with sex hormone deficiencies secondary to chromosomal or gonadal problems. This is a presentation of an unusual patient who was a trained tenor singer and was found to have hypogonadism on a premarital health examination. Administration of replacement testosterone resulted in significant vocal register and voice quality changes.     

Symmetry analysis for uniaxial compression of a hypoplastic granular material

A variety of modelling approaches currently exist to describe and predict the diverse behaviours of granular materials. One of the more sophisticated theories is hypoplasticity, which is a stress-rate theory of rational continuum mechanics with a constitutive law expressed in a single tensorial equation. In this paper, a particular version of hypoplasticity, due to Wu [2], is employed to describe a class of one-dimensional granular deformations. By combining the constitutive law with the conservation laws of continuum mechanics, a system of four nonlinear partial differential equations is derived for the axial and lateral stress, the velocity and the void ratio. Under certain restrictions, three of the governing equations may be combined to yield ordinary differential equations, whose solutions can be calculated exactly. Several new analytical results are obtained which are applicable to oedometer testing. In general this approach is not possible, and analytic progress is sought via Lie symmetry analysis. A complete set or “optimal system” of group-invariant solutions is identified using the Olver method, which involves the adjoint representation of the symmetry group on its Lie algebra. Each element in the optimal system is governed by a system of nonlinear ordinary differential equations which in general must be solved numerically. Solutions previously considered in the literature are noted, and their relation to our optimal system identified. Two illustrative examples are examined and the variation of various functions occuring in the physical variables is shown graphically. Received: February 3, 2004; revised: June 2, 2004     

New stress and velocity fields for highly frictional granular materials

The idealized theory for the quasi-static flow of granular materialswhich satisfy the Coulomb–Mohr hypothesis is considered.This theory arises in the limit as the angle of internal frictionapproaches /2, and accordingly these materials may be referredto as being ‘highly frictional’. In this limit,the stress field for both two-dimensional and axially symmetricflows may be formulated in terms of a single nonlinear second-orderpartial differential equation for the stress angle. To obtainan accompanying velocity field, a flow rule must be employed.Assuming the non-dilatant double-shearing flow rule, a furtherpartial differential equation may be derived in each case, thistime for the streamfunction. Using Lie symmetry methods, a completeset of group-invariant solutions is derived for both systems,and through this process new exact solutions are constructed.Only a limited number of exact solutions for gravity-drivengranular flows are known, so these results are potentially importantin many practical applications. The problem of mass flow througha two-dimensional wedge hopper is examined as an illustration.     

Unusual Hydrogen-bonding Networks Consisting of π-Extended 4,4′-Bipyridines and Chloranilic Acid

Hydrogen-bonding networks of π-extended 4,4′-bipyridines, 2,5-di(4-pyridyl)thiophene (1), 2,5-di(4-pyridyl)furan (2) and 1,4-di(4-pyridyl)benzene (3) with 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid, CA) have been investigated. The dipyridyl compounds afforded complexes 4 [(dication of 1)·(monoanion of CA)²], 5 [(dication of 2)·(dianion of CA)·(MeOH)] and 6 [(3)·(dication of 3)·(dianion of CA)·(H²O)⁶] with CA. X-ray structure analyses revealed the formation of unusual molecular tape and sheet structures involving N–H ?O, O–H ?O, C–H ?O and N–H ?N hydrogen bonds, where the aromatic spacer groups play an important role in constructing the unique crystal structures.     

CHAOS AND MULTIPLE PERIODS IN AN UNSYMMETRICAL SPRING AND DAMPING SYSTEM WITH CLEARANCE

Chaos and multiple periods are presented for the harmonically excited unsymmetrical spring and damping system with clearance. This paper demonstrates the non-linear behaviour of the motion through simulation and experiment. Intensive care and caution are taken in the experiments to observe the chaos and the multiple periods properly. The focus in this paper is mainly on the change of the bilinear spring stiffness ratio as a prime factor by which chaotic motions occur from quasi-periodic motion. Other investigations and effects on motion are also discussed for the changing of the extent of clearance. The investigations are based on frequency response curves. To understand the dynamics of the non-linearity of this model, all possible data processing and displaying techniques are taken into account. To observe the overall phenomena of this bilinear system, the resonance curves and the bifurcation diagrams are taken thoroughly for a wide frequency region.     

Trace element analysis of whole blood and urine samples of diabetic patients

A number of samples of whole blood, and urine from diabetic and non-diabetic persons have been analyzed for their trace elemental contents using the proton-induced X-ray emission. The elemental contents of the diabetic and non-diabetic samples are compared.     

Tests of significance using selected sample quantiles

Large sample tests of significance for the location parameter, the scale parameter, and quantiles for a location-scale family of distributions based on a few optimally chosen sample quantiles are considered.     

Stability and convergence of the spectral Lagrange-Galerkin method for mixed periodic/non-periodic convection-dominated diffusion problems

We present a convergence analysis of the spectral Lagrange-Galerkinmethod for mixed periodic/non-periodic convection-diffusionproblems. The scheme is unconditionally stable, independentof the diffusion coefficient, even in the case when numericalquadrature is used. The theoretical predictions are illustratedby a series of numerical experiments. For the periodic case,our results present a significant improvement on those givenby Süli & Ware (1991) SIAM J. Numer.Anal.28, 423-445).     

Analysis of Voice and Quantitative Measurement of Glottal Gap After Thyroplasty Type I in the Treatment of Unilateral Vocal Paralysis

Thyroplasty type I is one of several surgical treatments in which improving the voice of unilateral vocal fold paralysis is the ultimate objective. The goal of the surgery is the medialization of the paralyzed vocal fold. The purpose of this study is to evaluate the effectiveness of thyroplasty type I through acoustical analysis, aerodynamic measures, and quantitative videostroboscopic measurements. We report on 20 patients with unilateral vocal cord paralysis who underwent thyroplasty type I. We performed preoperative and postoperative video image analysis (normalized glottal gap area) and computer-assisted voice analysis (fundamental frequency, jitter, shimmer, noise-to-harmonic ratio, mean phonation time, mean flow rate, mean subglottic pressure) in all patients. The glottal gap was significantly reduced after thyroplasty type I. Postoperative voice quality was characterized by an improved pitch and amplitude pertubation (jitter and shimmer), phonation time (mean phonation time), and subglottic pressure (mean subglottic pressure). Thyroplasty type I is an effective method for regaining glottal closure and vocal function.     

Vocal Nodules and Laryngeal Morphology

Our purpose was to study the occurrence of vocal fold nodules under conditions of habitual vocal abuse associated with increased laryngeal muscle tension, to identify the existence of a relationship between vocal nodules and laryngeal morphology. We studied one group of 30 subjects with vocal nodules, 18 to 50 years old, who were compared with two control groups, one of females and one of males, consisting of 30 subjects each. The parameters evaluated were: type of vocal folds coaptation, glottic proportion (GP) and abduction angle (AA), obtained by videotelelaryngoscopy. In the nodules group, the larynges presented a mean value of GP similar to that of the female group, both of which were lower than the mean GP value of the male group. On the other hand, the mean AA was lower than the one in the female group, and closer to the one in the male group. We concluded that vocal nodules were present only in larynges with a predominantly young female morphology, with functional limitations of abduction.