How do ovarian follicles interact? A many-body problem with unusual symmetry and symmetry-breaking properties

The assumption that hormonal feedback regulates ovarian follicle growth is used to formulate a many-body problem in which interactions are spatially independent. This mechanism of interaction is shown to be sufficient to account for the regulation of ovulation number. A method is also developed to test if this assumption is consistent with the observed spatial distribution of follicles in the Rhesus monkey ovary.     

Risk factors and management of vocal cord hemorrhages: An experience with 44 cases

Risk factors for vocal cord hemorrhages were reviewed in 44 professional voice users. In a majority of cases, the direct cause of hemorrhage was temporally related to singing, public speaking, or some form of forceful laryngeal activity. Sixteen of the 44 patients had a concomitant upper respiratory tract infection, and in the case of women patients, eight of 30 had hormonal imbalances. These included abnormal menstrual cycles, use of estrogen supplements, gynecological surgery, and the use of birth control pills. In most of these cases, correction of the underlying hormonal disturbance prevented the recurrence of bleeding episodes. We stress that such abnormalities should be ruled out by history and appropriate tests when necessary, to prevent the occasional crippling sequelae of vocal cord hemorrhages and review the various treatment options available for this condition.     

Combinatorics of orientation reversing polygons

We give two combinatorial characterizations of orientation reversing polygons in graphs embedded on surfaces (r-polygons) and use the notion of skew embedding introduced in [7] to characterize parity embeddings: an embedding has its odd polygons coinciding with itsr-polygons if and only if the skew embedding is in an orientable surface. The concept of imbalance, central for the proof, does not seem to appear explicitly before in the literature. Possible algorithmic implications of the parity embedding theorem are briefly discussed.     

Sex hormones and the female voice

In the following, the authors examine the relationship between hormonal climate and the female voice through discussion of hormonal biochemistry and physiology and informal reporting on a study of 197 women with either premenstrual or menopausal voice syndrome. These facts are placed in a larger historical and cultural context, which is inextricably bound to the understanding of the female voice. The female voice evolves from childhood to menopause, under the varied influences of estrogens, progesterone, and testosterone. These hormones are the dominant factor in determining voice changes throughout life. For example, a woman's voice always develops masculine characteristics after an injection of testosterone. Such a change is irreversible. Conversely, male castrati had feminine voices because they lacked the physiologic changes associated with testosterone. The vocal instrument is comprised of the vibratory body, the respiratory power source and the oropharyngeal resonating chambers. Voice is characterized by its intensity, frequency, and harmonics. The harmonics are hormonally dependent. This is illustrated by the changes that occur during male and female puberty: In the female, the impact of estrogens at puberty, in concert with progesterone, produces the characteristics of the female voice, with a fundamental frequency one third lower than that of a child. In the male, androgens released at puberty are responsible for the male vocal frequency, an octave lower than that of a child. Premenstrual vocal syndrome is characterized by vocal fatigue, decreased range, a loss of power and loss of certain harmonics. The syndrome usually starts some 4-5 days before menstruation in some 33% of women. Vocal professionals are particularly affected. Dynamic vocal exploration by televideoendoscopy shows congestion, microvarices, edema of the posterior third of the vocal folds and a loss of its vibratory amplitude. The authors studied 97 premenstrual women who were prescribed a treatment of multivitamins, venous tone stimulants (phlebotonics), and anti-edematous drugs. We obtained symptomatic improvement in 84 patients. The menopausal vocal syndrome is characterized by lowered vocal intensity, vocal fatigue, a decreased range with loss of the high tones and a loss of vocal quality. In a study of 100 menopausal women, 17 presented with a menopausal vocal syndrome. To rehabilitate their voices, and thus their professional lives, patients were prescribed hormone replacement therapy and multi-vitamins. All 97 women showed signs of vocal muscle atrophy, reduction in the thickness of the mucosa and reduced mobility in the cricoarytenoid joint. Multi-factorial therapy (hormone replacement therapy and multi-vitamins) has to be individually adjusted to each case depending on body type, vocal needs, and other factors.