ExpertGlossary terms starting with P

3,647 terms

Pharmacogenomics The study of the interaction of an individual's genetic makeup and response to a drug.
pharmacokinetics (FAR-muh-koh-kih-NEH-tix) The activity of drugs in the body over a period of time, including the processes by which drugs are absorbed, distributed in the…
pharmacology (FAR-muh-KAH-loh-jee) The study of the origin, chemistry, and uses of drugs and their effects on the body.
pharmacopoeia A book describing chemicals, drugs, and other substances and how they are used as medicines. It is prepared by a recognized authority.
Pharmacy A place where drugs are sold; a drugstore.
Pharming A method of capturing sensitive information (such as Social Security numbers and passwords) by fooling a user into entering such information on a fake Web…
pharyngeal cancer (fuh-RIN-jee-ul KAN-ser) Cancer that forms in tissues of the pharynx (the hollow tube inside the neck that starts behind the nose and ends at the top of…
pharynx (FAIR-inks) The hollow tube inside the neck that starts behind the nose and ends at the top of the trachea (windpipe) and esophagus (the tube that goes to…
Phase Alternating current is carried by conductors and a ground to residential, commercial, or industrial consumers.
phase angle Of a periodic wave, the number of suitable units of angular measure between a point on the wave and a reference point.
phase bandwidth Of a network or device, the width of the continuous frequency range over which the phase-vs.
Phase Change A method of storing information on rewritable optical discs.
phase coherence The state in which two signals maintain a fixed phase relationship with each other or with a third signal that can serve as a reference for each.
phase coherent See phase coherence.
phase constant The imaginary part of the axial propagation constant for a particular mode, usually expressed in radians per unit length.
phase delay In the transmission of a single-frequency wave from one point to another, the delay of an arbitrary point in the wave that identifies its phase.
phase departure A phase deviation from a specified value. 2. An unintentional deviation from the nominal phase value.
phase detector A circuit or instrument that detects the difference in phase between corresponding points on two signals.
phase deviation In phase modulation, the maximum difference between the instantaneous phase angle of the modulated wave and the phase angle of the unmodulated carrier.
phase diagram A graphic representation of the phase relationships between two or more waveforms.
phase difference The time interval or phase angle by which one wave leads or lags another. Synonym phase offset.
phase distortion Distortion that occurs when (a) the phase-frequency characteristic is not linear over the frequency range of interest, i.e.
phase equalizer See delay equalizer.
phase flux reversal In phase-encoded recording, a magnetic flux reversal written at the nominal midpoint between successive "1" bits, or between successive "0" bits, to…
phase hit See yyhit.
phase I detoxification A process in which the liver uses one of two major enzyme pathways to change a toxic substance, such as an anticancer drug, into a less toxic substance…
phase I trial The first step in testing a new treatment in humans. These studies test the best way to give a new treatment (for example, by mouth, intravenous infusion…
phase I/II trial A trial to study the safety, dosage levels, and response to a new treatment.
phase II detoxification A process in which the liver uses one of two major enzyme pathways to change a toxic substance, such as an anticancer drug, into a less toxic substance…
phase II trial A study to test whether a new treatment has an anticancer effect (for example, whether it shrinks a tumor or improves blood test results) and whether it…
phase II/III trial A trial to study response to a new treatment and the effectiveness of the treatment compared with the standard treatment regimen.
phase III trial A study to compare the results of people taking a new treatment with the results of people taking the standard treatment (for example, which group has…
phase instability The fluctuation of the phase of a wave, relative to a reference. Note: The fluctuation is often from unknown causes.
phase interference fading The variation in signal amplitude produced by the interaction of two or more signal elements with different relative phases.
phase inversion Introduction of a phase difference of 180°. Note: Phase inversion may occur with a random or periodic, symmetrical or non-symmetrical waveform, although…
phase IV trial After a treatment has been approved and is being marketed, it is studied in a phase IV trial to evaluate side effects that were not apparent in the phase…
phase jitter Rapid, repeated phase perturbations that result in the intermittent shortening or lengthening of signal elements.
phase jump A sudden phase change in a signal.
phase linearity Direct proportionality of phase shift to frequency over the frequency range of interest.
phase measurement tolerance The maximum allowable difference between a phase measurement and the actual phase value.
phase modulation (PM) Angle modulation in which the phase angle of a carrier is caused to depart from its reference value by an amount proportional to the instantaneous value…
phase noise In an oscillator, rapid, short-term, random fluctuations in the phase of a wave, caused by time-domain instabilities.
phase nonlinearity Lack of direct proportionality of phase shift to frequency over the frequency range of interest.
phase offset Synonym phase difference.
Phase One Engineering Team (POET) OBSOLETE. An FFRDC providing technical support to the Phase I Program Office. Now referred to as POET.
phase perturbation Any shifting (often quite rapid), from whatever cause, in the phase of a signal. Note 1: The shifting in phase may appear to be random, cyclic, or both.
phase quadrature See quadrature.
phase shift The change in phase of a periodic signal with respect to a reference.
phase state The coupling or repulsion of two linked genes.
phase term In the propagation of an electromagnetic wave in a uniform waveguide, such as an optical fiber or metal waveguide, the parameter that indicates the phase…
phase transients Perturbations in phase of limited duration seen at synchronization interfaces. Typical duration is several time constants of the slave clock which…
Phase Transition Change from one state of energy to another.
phase velocity The velocity of propagation of a uniform plane wave, given by (a) the product of the wavelength and the frequency divided by (b) the refractive index of…
Phase-Change Material A material that can be used to store thermal energy as latent heat. Various types of materials have been and are being investigated such as inorganic…
phase-encoded (PE) recording Binary recording on magnetic media, such as magnetic disks, tapes, and cards, in which a "1" is represented by a magnetic flux reversal to the polarity of…
phase-frequency characteristic A Cartesian-coordinate plot of phase shift as the dependent variable, versus frequency as the independent variable.
phase-frequency distortion Synonym phase distortion.
phase-locked loop (PLL) An electronic circuit that controls an oscillator so that it maintains a constant phase angle relative to a reference signal.
phase-shift keying (PSK) In digital transmission, angle modulation in which the phase of the carrier is discretely varied in relation either to a reference phase or to the phase…
phase-shift signaling Synonym phase-shift keying.
Phased Array The arranging of radiating or receiving elements that, although physically stationary, is electronically steer-able and can switch rapidly from one target…
Phased Array Tracking Radar Intercept On Target (missile) (PATRIOT) A point or limited area defense system originally built to intercept aircraft. PAC-3 improvements, which will give it greater capability against theater…
Phased Deployment The sequential steps of element deployments leading to a designated system capability that is realizable with fiscal and technological constraints.
phasing In facsimile transmission and reception, the process by which the start of the scanning line or lines is made to correspond to one edge of the object…
PHB Abbreviation for polyhydroxybutyrate.
phenethyl isothiocyanate A substance being studied in the prevention of cancer. It is a naturally occurring compound found in some cruciferous vegetables. Also called PEITC.
phenobarbital A drug that is used to treat seizures and as a sedative. It is being studied in the treatment of diarrhea and for its ability to increase the antitumor…
Phenocopy An environmentally induced, non hereditary variation in an organism, resembling a genetically determined trait.
phenol (FEE-nol) A very poisonous chemical substance made from tar and also found in some plants and essential oils (scented liquid taken from plants).
phenolic oxidation Common aspect of the wound response in plants. Phenolic oxidation is often indicated by blackening of tissue and it may be a precursor to growth…
phenolics Compounds with hydroxyl group(s) attached to the benzene ring, forming esters, ethers and salts.
Phenomenological Model A computer model used to calculate air pollution concentrations. A phenomenological model focuses on an individual phenomenon, such as plume impingement…
Phenomenology The topological classification of a class of phenomena. Phenomenology efforts collect and analyze optical and radar signature data, and model phenomena…
phenothiazine (FEE-noh-THY-uh-zeen) A type of drug that is used to treat severe mental and emotional disorders, severe nausea and vomiting, and certain other conditions.
Phenotype The observable characteristics of an organism, the expression of gene alleles (genotype) as an observable physical or biochemical trait. See Genotype.
Phenotypic characteristics The genetically and environmentally determined physical characteristics of an organism.
phenoxodiol A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called signal transduction inhibitors.
phenylacetate A substance that is being studied in the treatment of cancer.
phenylbutyrate A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called differentiating agents.
phenylketonuria (FEH-nil-KEE-tone-yoor-ee-uh) An inherited disorder that causes a build-up of phenylalanine (an amino acid) in the blood.
pheochromocytoma (FEE-oh-KROH-moh-sy-TOH-muh) Tumor that forms in the center of the adrenal gland (gland located above the kidney) that causes it to make too much…
pheresis (fer-E-sis) A procedure in which blood is collected, part of the blood such as platelets or white blood cells is taken out, and the rest of the blood is…
Pheromone A hormone-like substance that is secreted into the environment.
PHI Photonic Hit Indicator.
Phiezometer In hydrologic terms, an instrument used to measure pressure head in a conduit, tank, soil, etc. They are used in dams to measure the level of saturation.
PHIGS Programmers Hierarchical Interactive Graphics System.
Philadelphia chromosome (FIH-luh-DEL-fee-uh KROH-muh-some) An abnormality of chromosome 22 in which part of chromosome 9 is transferred to it.
Philadelphia rod A leveling rod in which the hundredths of feet, or eights of inches, are marked by alternate bars of color the width of the measurement.
philosophical (FIH-luh-SAH-fih-kul) Having to do with the deeper questions of life and with a person's basic beliefs, ideas, and attitudes.
Phishing When internet fraudsters impersonate a business in an attempt to trick you into giving out your personal information, such as usernames, passwords, and…
phishing confidence level A property of each e-mail message that the Office Outlook 2003 Junk E-mail Filter stamps as a property on the message when it is processed in the Outlook…
phlebitis (fleh-BY-tis) Inflammation (redness, swelling, pain, and heat) of a vein, usually in the legs. Phlebitis may be caused by infection, injury, or irritation.
phlebotomy (fleh-BAH-toh-mee) The puncture of a vein with a needle for the purpose of drawing blood. Also called venipuncture.
phlegm (flem): Thick mucus from the airways of the body.
phlegm (flem) A more than normal amount of thick mucus made by the cells lining the upper airways and lungs.
phloem Specialized vascular plant tissue for the transport of assimilates (generally sugars) from the point of synthesis (in the leaf) to other parts of the…
phobia (FOH-bee-uh) An extreme, irrational, fear of something that may cause a person to panic.
phon In acoustics, a unit of subjective loudness level equal to the sound pressure level in dB compared to that of an equally loud standard sound.
phone Abbreviation for telephone, telephony. 2. Loosely, the voice-operation mode in radio communications.
phonetic alphabet A list of standard words used to identify letters in a message transmitted by radio or telephone.