phase (faz)

1. A stage in the course of change or development. 2. A homogeneous, physically distinct, and separable portion of a heterogeneous system; e.g., oil, gum, and water are three p.'s of an emulsion. 3. The time relationship between two or more events. 4. A particular part of a recurring time pattern or wave form. See also stage, period. [G. phasis, an appearance]
anal p. in psychoanalytic personality theory, the stage of psychosexual development, occurring when a child is between 1 and 3 years, during which activities, interests, and concerns are centered around the anal zone.
aqueous p. the water portion of a system consisting of two liquid p.'s, one mainly water, the other a liquid immiscible with water (e.g., benzene, ether).
cis p. See coupling p.
continuous p. external p
coupling p. the physical relationship of two syntenic genes. If they are on the same chromosome, they are said to be "in coupling" or "in the cis p."; if on opposite members of a chromosome pair, "in repulsion" or "in the trans p."
discontinuous p. internal p
dispersed p. internal p
dispersion p. external p
eclipse p. eclipse period
p. encoding in magnetic resonance imaging, the technique of inducing a gradient in the magnetic field in the Y-axis to induce phase differences with location.gradient encoding;
eruptive p. that period in the tooth formation which includes the development of the roots, periodontal ligament, and dentogingival junction of the tooth.
external p. the medium or fluid in which a disperse is suspended.continuous p., dispersion medium, dispersion p., external medium;
Gap1 p. Gap1 period
Gap2 p. Gap2 period
genital p. in psychoanalytic personality theory, the final stage of psychosexual development, occurring during puberty, in which the individual's psychosexual development is so organized that sexual gratification can be achieved from genital-to-genital contact and the capacity exists for a mature affectionate relationship with an individual of the opposite sex. See phallic p.
growth p. a stage in the enlargement of a neoplasm.
horizontal growth p. an early stage of development of cutaneous melanoma by intraepidermal spread of atypical melanocytes.
internal p. the particles contained in a colloid solution.discontinuous p., dispersed p;
lag p. a brief period in the course of the growth of a bacterial culture, especially at the beginning, during which the growth is very slow or scarcely appreciable.
latency p. in psychoanalytic personality theory, the period of psychosexual development in children, extending from about age 5 to the beginning of adolescence at age 12, during which the apparent cessation of sexual preoccupation during this period stems from a strong, aggressive blockade of libidinal and sexual impulses in an effort to avoid oedipal relationships; during this p., boys and girls are inclined to choose friends and join groups of their own sex.latency period;
logarithmic p. exponential, a period in the course of growth of a bacterial culture in which maximal multiplication is occurring by geometrical progression; thus, if the logarithms of their numbers are plotted against time, they will form a straight upward line.
luteal p. that portion of the menstrual cycle extending from the time of formation of the corpus luteum to the onset of menses, usually 14 days in length; short luteal p. , a period of 10 days or less between ovulation and the onset of menses, frequently associated with infertility.
M p. mitotic period
meiotic p. the stage of nuclear changes in the sexual cells during which reduction of the chromosomes takes place; it embraces the cell generations of the spermatocytes and oocytes.reduction p;
negative p. the period during which the opsonic index is lowered following the injection of a vaccine.
oedipal p. in psychoanalysis, a stage in the psychosexual development of the child, characterized by erotic attachment to the parent of the opposite sex, repressed because of fear of the parent of the same sex; usually occurring between the ages of 3 and 6 years.oedipal period;
oral p. in psychoanalytic personality theory, the earliest stage in psychosexual development, lasting through the first 18 months of life, during which the oral zone is the center of the infant's needs, expression, gratification, and pleasurable erotic experiences; has a strong influence on the organization and development of the child's psyche.
phallic p. in psychoanalytic personality theory, the stage in psychosexual development, occurring when a child is between 2 and 6 years of age, during which interest, curiosity, and pleasurable experiences are centered around the penis in boys and the clitoris in girls. See genital p.
positive p. the period following the negative p., during which the opsonic index rises.
postmeiotic p. the stage following that of reduction of the chromosomes in the sexual cells, representing the mature forms of these cells, ending with the conjugation of the nuclei in the impregnated ovum.postreduction p;
postmitotic p. Gap1 period
postreduction p. postmeiotic p
poststationary p. the period in the growth of a bacterial culture in which growth is declining.
pregenital p. in psychoanalysis, the collective psychosexual development p.'s preceding the genital p.
premeiotic p. the stage of nuclear changes in the sexual cells before the reduction of the chromosomes, embracing the cell generations up to that of the spermatogonia and oogonia.prereduction p;
premitotic p. Gap2 period
pre-oedipal p. in psychoanalysis, the collective p.'s of psychosexual development preceding the oedipal p.
prereduction p. premeiotic p
radial growth p. the early pattern of growth of cutaneous malignant melanoma, in which tumor cells spread laterally in the epidermis.
reduction p. meiotic p
S p. synthesis period
stationary p. 1. the period in the course of growth of a bacterial culture during which the multiplication of the organisms becomes gradually less and the bacteria undergoing division are in equilibrium with those dying; 2. referring to the usually solid, nonmobile component in partition chromatography.
supernormal recovery p. a brief period during the recovery of cardiac muscle following excitation when diseased muscle is more (i.e., less abnormally) excitable; corresponds to the end of the T wave in the ECG.
synaptic p. synapsis
trans p. See coupling p.
vertical growth p. spread of melanoma cells from the epidermis into the dermis and later the subcutis, from which site metastasis may take place.
vulnerable p. a period in the cardiac cycle during which an ectopic impulse may lead to repetitive activity such as flutter or fibrillation of the affected chamber.


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