All articles starting with P
28,818 articles
Pseudo-Landau levels
Pseudo-Landau levels (PLLs) are quantized electronic states in strained graphene, where strain or a moiré pattern creates pseudo-magnetic fields that mimic Landau levels without an external magnetic field.
Pseudo-Meigs syndrome
Pseudo-Meigs syndrome is a rare condition in which a pelvic or abdominal tumor other than an ovarian fibroma causes ascites and pleural effusion that resolve after tumor resection.
Pseudo-observations
Pseudo-observations are rank-transformed values of a multivariate sample, scaled by 1/(n+1) so margins are approximately uniform, making them the standard input for semiparametric copula inference.
Pseudo-penis
Pseudo-penis: an enlarged, erectile, penis-like clitoris, best known in the female spotted hyena, the only mammal that urinates, mates, and gives birth through a clitoris; also occurs in moles, lemurs, and juvenile fossas.
Pseudo-Riemannian manifold
A pseudo-Riemannian manifold, also called a semi-Riemannian manifold, is a smooth manifold with a non-degenerate metric tensor of indefinite signature, whose Lorentzian case is the spacetime geometry of general relativity.
Pseudo-rigid-body model
The pseudo-rigid-body model (PRBM) is a mechanism design method that represents compliant mechanisms as rigid links joined by springs, introduced by Howell and Midha in 1995.
Pseudo-spectral trajectory optimization
Pseudo-spectral trajectory optimization, also called orthogonal collocation, approximates state and control trajectories with global orthogonal polynomials and enforces dynamics by collocation at Gauss quadrature points.
Pseudo-TORCH syndrome type 1
Pseudo-TORCH syndrome type 1 (PTORCH1, BLC-PMG, Baraitser-Reardon syndrome) is an autosomal recessive OCLN-related disorder mimicking congenital TORCH infection, with microcephaly, band-like intracranial calcification, polymicrogyria, and intractable seizures.
Pseudo-von Willebrand disease
Pseudo-von Willebrand disease, also called platelet-type von Willebrand disease (PT-VWD), is a rare autosomal dominant bleeding disorder caused by GP1BA gain-of-function mutations that make platelets bind and lose von Willebrand factor, mimicking type 2B VWD but requiring platelet transfusions.
Pseudoalteromonas
Pseudoalteromonas, false Alteromonas, is a genus of Gram-negative aerobic marine Gammaproteobacteria split from Alteromonas in 1995, with about 50 species requiring seawater, many producing antimicrobial and anti-fouling compounds.
Pseudoaminopterin syndrome
Pseudoaminopterin syndrome, also called aminopterin syndrome sine aminopterin (ASSA, OMIM 600325), is an extremely rare genetic malformation syndrome mimicking aminopterin embryopathy without drug exposure, with skull, facial, and limb anomalies, intellectual deficit, and short stature; about 11 cases reported.
Pseudoarchaeology
Pseudoarchaeology, also called alternative or cult archaeology, interprets the past outside the scientific method to support predetermined conclusions, exemplified by von Däniken's Chariots of the Gods, ancient-astronaut claims, Atlantis, and media figures like Graham Hancock.
Pseudoazurin
Pseudoazurin (PAz) is a small blue copper protein (cupredoxin) from denitrifying bacteria such as Alcaligenes faecalis and Achromobacter cycloclastes, with a type 1 copper site (2 His, Cys, Met) that donates electrons to nitrite reductase and nitrous oxide reductase.
Pseudobulb
Pseudobulb: a thickened, bulblike modified stem above ground in many orchids (Cattleya, Dendrobium, Bulbophyllum), storing water, food, and CO2 in aerenchyma for CAM photosynthesis; old leafless ones are backbulbs used for propagation.
Pseudobulbar affect
Pseudobulbar affect (PBA), also called pathological laughing and crying or emotional incontinence, is a neurological syndrome of sudden involuntary crying or laughing incongruent with mood, occurring in ALS, MS, stroke, TBI, and dementias; treated with dextromethorphan/quinidine.
Pseudobulbar palsy
Pseudobulbar palsy, also called supranuclear bulbar paralysis, is a syndrome from bilateral corticobulbar tract lesions causing spastic dysarthria, dysphagia, brisk jaw jerk, and pseudobulbar affect, seen in stroke, ALS, MS, and Parkinson's disease.
Pseudocaeciliidae
Pseudocaeciliidae, false lizard barklice, is a family of bark lice (Psocodea: Psocomorpha) established by Pearman in 1936, with type genus Pseudocaecilius; about 300 species in 23 genera, mostly Asian, likely not monophyletic, and treated by some authors under the older name Calopsocidae.
Pseudocapacitor
A pseudocapacitor is an electrochemical energy storage device that stores charge through fast, reversible Faradaic redox reactions at electrode surfaces, achieving greater capacitance and energy density than electric double-layer capacitors.
Pseudoceros dimidiatus
Pseudoceros dimidiatus, the divided or tiger flatworm, is a polyclad flatworm (Pseudocerotidae) described by Graff in 1893 from the Great Barrier Reef; valid species, no synonyms, often confused with P. bifurcus and P. susanae.
Pseudoceros ferrugineus
Pseudoceros ferrugineus, commonly called the fuchsia flatworm, is a large marine polyclad flatworm described by Libbie Hyman in 1959, found on tropical Indo-Pacific reefs, where it feeds on colonial ascidians.
Pseudocheirus
Pseudocheirus, also called the ringtail possum genus (Pseudocheirus Ogilby, 1837), is an Australian marsupial genus of family Pseudocheiridae holding the eastern ringtail P. peregrinus and western ringtail P. occidentalis.
Pseudocode
Pseudocode is a plain-language, language-independent description of an algorithm's steps that resembles programming code but is meant for humans rather than execution, used for planning and teaching.
Pseudocumene
Pseudocumene is 1,2,4-trimethylbenzene, a flammable liquid hydrocarbon found in petroleum and coal tar, used chiefly to make trimellitic anhydride and as the Borexino neutrino detector's solvent.
Pseudocyst of pancreas
Pancreatic pseudocyst, a complication of acute or chronic pancreatitis and trauma, is an encapsulated enzyme-rich fluid collection with a fibrous wall lacking epithelium, maturing after 4 weeks; symptomatic cysts are drained, usually endoscopically.
Pseudocyst of spleen
Pseudocyst of spleen, also called secondary or false splenic cyst, is an epithelium-free fibrous-walled cyst, usually post-traumatic, accounting for 70-80% of nonparasitic splenic cysts and managed by spleen-preserving drainage or surgery.
Pseudodiastrophic dysplasia
Pseudodiastrophic dysplasia is an extremely rare autosomal recessive skeletal dysplasia marked by short limbs, severe clubfoot, joint dislocations, platyspondyly, and scoliosis, first described in 1974.
Pseudoephedrine
Pseudoephedrine, also sold as pseudoephedrine hydrochloride, is a sympathomimetic amine used as an oral nasal decongestant for congestion from colds, sinusitis, and hay fever.
Pseudoexfoliative open-angle glaucoma
Pseudoexfoliative open-angle glaucoma (PXG, PEXG, exfoliative glaucoma): secondary open-angle glaucoma from pseudoexfoliation material obstructing the trabecular meshwork; more aggressive than POAG, needing earlier surgery.
Pseudofeces
Pseudofeces (pseudo-faeces) are mucus-bound particles rejected by bivalve molluscs before ingestion, produced on gills and labial palps; term coined by Dodgson; enables particle selection and biodeposition.
Pseudofolliculitis barbae
Pseudofolliculitis barbae (PFB), razor bumps, is a chronic inflammatory ingrown-hair disorder of shaved beard and neck skin, predominantly affecting Black men with tightly curled hair; treated with grooming changes, topicals, and laser hair removal.