All articles starting with P
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Prefill-decode disaggregation
Prefill-decode disaggregation is a serving architecture that runs prompt processing and token generation for large language models on separate hardware, transferring the KV cache between them.
Prefix
Prefix (linguistics): a bound morpheme attached before a stem, as English re- or un-. Contrasted with suffixes, which are cross-linguistically more frequent; prefixes are shorter, phonologically independent, and can cue word category early.
Prefix code
A prefix code, also called a prefix-free or instantaneous code, is a variable-length code in which no codeword is a prefix of another, allowing unambiguous decoding without separators.
Prefix sum
A prefix sum, also called a scan or cumulative sum, is an operation on a list of numbers that produces a running total at each position.
Prefix tuning
Prefix tuning is a parameter-efficient fine-tuning method for pretrained transformers, introduced by Xiang Lisa Li and Percy Liang in 2021, that trains prefix vectors while the model stays frozen.
Prefix/context caching
Prefix/context caching is an inference technique that stores and reuses key-value states for shared prompt prefixes, cutting prefill cost and latency; adopted by major providers in 2024–2025, it discounts cache-hit tokens by 50 to 90%.
Prefoldin
Prefoldin (PFD, GIM complex) is a jellyfish-shaped heterohexameric chaperone of archaea and eukaryotes that captures unfolded proteins with coiled-coil tentacles and delivers them to group II chaperonin TRiC/CCT for folding.
Prefontaine (film)
Prefontaine (1997) is a biographical sports drama directed by Steve James, starring Jared Leto as runner Steve Prefontaine. Shot documentary-style on Super 16mm for Hollywood Pictures, released January 24, 1997, Metascore 55, rivaling Warner Bros.' Without Limits.
Preformed Cooper pairs
Preformed Cooper pairs are bound electron pairs that form above the superconducting transition temperature Tc without phase coherence, a scenario proposed to explain the pseudogap in underdoped cuprate superconductors.
Prefrontal cortex
Prefrontal cortex (PFC): the anterior frontal-lobe region supporting executive function, working memory, and socio-emotional behavior; about 30% of human cortical surface, matures into early adulthood, and is implicated in autism and schizophrenia.
Pregabalin
Pregabalin (Lyrica), a GABA-derivative anticonvulsant binding the alpha2-delta calcium channel subunit, treats neuropathic pain, fibromyalgia, and partial seizures; first approved 2004, discovered at Northwestern with NIH funding, and a controlled substance in the US, UK, and India.
Pregeometry (model theory)
In model theory, a pregeometry, known in combinatorics as a matroid, is a set with a finitary closure operator satisfying the Steinitz exchange property, abstracting linear span and algebraic closure.
PregMet trial
PregMet (Metformin in Pregnant PCOS Women, NCT00159536) and its successor PregMet2 (NCT01587378) are Norwegian-led randomized placebo-controlled trials of 2000 mg metformin in PCOS pregnancy; pooled data suggest reduced late miscarriage and preterm birth but no prevention of gestational diabetes.
Pregnancy
Pregnancy (gestation, prenatal period): the roughly 40-week period in which a fetus develops in the womb, divided into trimesters; zygote, embryo, then fetus; includes prenatal care, complications, and maternal mortality.
Pregnancy (mammals)
Pregnancy (mammals): viviparous reproduction in which embryos develop internally, nourished by a placenta. Viviparity evolved once in mammals; monotremes lay eggs, marsupials have short gestations, eutherians long ones.
Pregnancy category
Pregnancy category: letter-based drug risk classification (A, B, C, D, X; Australian A, B1-B3, C, D, X) for medicines in pregnancy. FDA abandoned its system in 2015 for the PLLR narrative format; Australia still uses categories.
Pregnancy dermatoses
Pregnancy dermatoses are pruritic inflammatory skin disorders specific to pregnancy and the immediate postpartum period: pemphigoid gestationis, polymorphic eruption of pregnancy (PUPPP), intrahepatic cholestasis of pregnancy, and atopic eruption of pregnancy, distinguished by onset, lesions, and fetal risk.
Pregnancy diagnosis in animals
Pregnancy diagnosis in animals is the set of veterinary methods, chiefly rectal palpation, ultrasound, and blood assays, used to determine whether a farm or domestic animal is pregnant.
Pregnancy fetishism
Pregnancy fetishism, also called maiesiophilia or maieusiophilia, is sexual attraction to pregnant bodies or pregnancy as an erotic phenomenon; distinguished from clinical fetishism, which is limited to nonliving objects.
Pregnancy from rape
Pregnancy from rape, or rape-related pregnancy, is conception resulting from sexual assault. Key figures: 5.0% per-rape pregnancy rate among women aged 12–45, about 32,101 US pregnancies yearly, and 1 in 20 US women affected lifetime.
Pregnancy options counseling
Pregnancy options counseling is a person-centered, nondirective counseling method in which a clinician gives a patient with an unintended pregnancy unbiased information on continuing the pregnancy, adoption, and abortion.
Pregnancy Outcome
Pregnancy outcome (MeSH D011256) is the result of conception and ensuing pregnancy: live birth, stillbirth, spontaneous abortion, or induced abortion, including outcomes after assisted reproduction; a standardized endpoint in obstetric research and surveillance.
Pregnancy over age 50
Pregnancy over age 50: postmenopausal or near-postmenopausal pregnancy achieved almost exclusively by donor-egg IVF; US births 1,230 in 2022; elevated risks of preeclampsia, gestational diabetes, cesarean, and maternal death.
Pregnancy test
Pregnancy test: home or clinical qualitative immunoassay detecting human chorionic gonadotropin (hCG) in urine; most reliable from the first day of a missed period, with brand accuracy varying widely from packaging claims.
Pregnancy-associated spontaneous coronary artery dissection
Pregnancy-associated spontaneous coronary artery dissection (P-SCAD, PASCAD) is a non-atherosclerotic coronary artery tear during pregnancy or postpartum, the leading cause of pregnancy-related myocardial infarction, managed mainly conservatively.
Pregnanediol
Pregnanediol, 5β-pregnane-3α,20α-diol, is an inactive urinary metabolite of the hormone progesterone; its excretion rises after ovulation and in pregnancy, making it a marker of progesterone production.
Pregnanolone
Pregnanolone, also called 3α,5β-tetrahydroprogesterone, is a neurosteroid metabolite of progesterone that positively modulates GABAA receptors; like its isomer allopregnanolone, it elicits sedative, anxiolytic, and anticonvulsant effects.
Pregnenolone
Pregnenolone (PREG, 5-pregnen-3β-ol-20-one) is the common steroid precursor formed from cholesterol by CYP11A1/P450scc in mitochondria, an abundant neurosteroid, an OTC supplement, and an experimental drug in pain and schizophrenia trials.
Pregón
Pregón is a Spanish word for a proclamation made aloud in public places, and by extension the street cry of a vendor announcing goods or services.
Prehensile grasping
Prehensile grasping is robotic manipulation in which a gripper holds an object by closing fingers or jaws around it, rather than pushing, rolling, or throwing it.