Those characteristics that distinguish one SEX from the other. The primary sex characteristics are the OVARIES and TESTES and their related hormones. Secondary sex characteristics are those which are masculine or feminine but not directly related to reproduction

The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization)

Differentiable dynamical systems -- Software. : The beauty of fractals lab : graphics software for the Macintosh / Hartmut Jürgens, Heinz-Otto Peitgen, Dietmar Saupe ; software written by Thomas Eberhardt and Marc Parmet

Differential calculus -- History. : The history of the calculus and its conceptual development : the concepts of the calculus / Carl B. Boyer ; with a foreword by Richard Courant

Determination of which one of two or more diseases or conditions a patient is suffering from by systematically comparing and contrasting results of diagnostic measures

Differential-Differenzengleichung : Expansions in series of solutions of linear difference-differential and infinite order differential equations with constant coefficients / by Douglas G. Dickson