All articles starting with D
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Delta-v (Δv)
Delta-v (Δv, delta-vee) is the change in velocity a spacecraft's propulsion system can produce, measured in km/s and serving as the basic currency of mission design, since required propellant grows exponentially with it.
Delta-v budget
A delta-v budget is the sum of all velocity changes a spacecraft must generate over its mission, from launch correction through orbit maintenance to disposal, plus the propellant those maneuvers require.
Delta, British Columbia
Delta is a city in the Metro Vancouver region of British Columbia, on the south side of the Fraser River's mouth, with three communities: Ladner, Tsawwassen, and North Delta.
Delta3 Tauri
Delta3 Tauri, also designated 68 Tauri, is a naked-eye binary star in Taurus, a Hyades cluster member about 149 light-years away and a blue straggler.
Deltacommissie
The Deltacommissie, or Delta Commission, is the name of two Dutch state advisory committees on water safety, appointed after the 1953 flood and again in 2007.
Deltacoronavirus (δ-CoV)
Deltacoronavirus (δ-CoV), a coronavirus genus in Orthocoronavirinae lacking nsp1 in ORF1a, with subgenera Andecovirus, Buldecovirus, Herdecovirus; mostly avian viruses, plus porcine deltacoronavirus (Deltacoronavirus suis, HKU15) infecting pigs and occasionally humans.
Deltamethrin
Deltamethrin, a synthetic pyrethroid insecticide discovered by Michael Elliott in 1974 at Rothamsted, CAS 52918-63-5, acts on sodium channels and is used in crop protection, IRS, and mosquito nets.
Deltaproteobacteria
Deltaproteobacteria, a class of Proteobacteria (Kuever et al. 2006), groups sulfate-reducing, sulfur-reducing, predatory, and metal-respiring bacteria such as Desulfovibrio, Myxococcus, and Geobacter; genome-scale phylogenomics since 2020 reassigns most members to the phyla Desulfobacterota, Myxococcota, SAR324, and Bdellovibrionota.
Deltaretrovirus bovleu
Deltaretrovirus bovleu, also called bovine leukemia virus (BLV), is the ICTV deltaretrovirus species infecting cattle and causing enzootic bovine leukosis, an 8.3 kb retrovirus with tax, rex, and hbz genes.
Deltarune
Deltarune (DELTARUNE) is Toby Fox's episodic RPG follow-up to Undertale, released in chapters from 2018; Chapters 1-5 are out (Chapter 5, June 2026), with Chapters 6-7 planned as free updates, bullet-hell turn-based combat, and an 86 Metascore.
Deltas del Estero Real y Llanos de Apacunca
Deltas del Estero Real y Llanos de Apacunca, Ramsar site no. 1136 (2001), an 81,700-ha estuarine mangrove and delta wetland in Chinandega, Nicaragua, part of the Gulf of Fonseca system, protecting endemic wild maize Zea luxurians.
Deltocyathus calcar
Deltocyathus calcar, the deepsea star coral, is a small solitary free-living stony coral of the western Atlantic, described by Pourtalès in 1874, living at 81-675 m depth.
Deltoid muscle
Deltoid muscle (musculus deltoideus), the triangular shoulder-cap muscle with clavicular, acromial, and spinal parts; axillary nerve (C5, C6); abducts, flexes, extends the arm; preferred adult vaccination site.
Deltron 3030
Deltron 3030: alternative hip-hop supergroup of Del the Funky Homosapien, Dan the Automator, and Kid Koala; 2000 self-titled sci-fi concept album set in dystopian year 3030, sequel Event II (2013), third album reported done.
Deluge (history)
The Deluge (potop szwedzki) is the Swedish invasion and occupation of the Polish-Lithuanian Commonwealth, 1655–1660, ending with the Peace of Oliva; it caused collapse, plunder, and disputed population losses.
Delulu Pack
Delulu Pack is the second EP (six tracks, 17:11) by K-pop girl group KiiiKiii, released January 26, 2026 by Starship Entertainment, led by title track "404 (New Era)" with pre-release "To Me From Me (Prod. Tablo)".
Delusion
Delusion: a fixed false belief held with strong conviction despite conflicting evidence and not accepted by the person's culture; a core psychotic symptom defined by DSM-IV/DSM-5 and Jaspers' ununderstandability criterion, studied via aberrant salience and prediction-error models.
Delusion of being controlled
Delusion of being controlled (作為妄想, ICD-11 MB26.01): a psychotic symptom in which a person believes external forces control their thoughts, feelings, or actions; a Schneider first-rank symptom occurring in about 20% of schizophrenia patients, de-emphasized in DSM-5 and ICD-11 diagnostics.
Delusion of guilt
Delusion of guilt (ICD-11 MB26.02, 罪業妄想) is a psychotic symptom of exaggerated self-blame and deserved punishment, occurring mainly in psychotic depression (40% of psychotic major depression) and rare in schizophrenia.
Delusion of impoverishment
Delusion of impoverishment (delusion of poverty), ICD-11 MB26.0C: a fixed false conviction of being or becoming destitute despite contrary evidence, seen in psychotic depression and Cotard syndrome.
Delusion of reference
A delusion of reference is the false belief that neutral events and others' behavior carry special, usually negative, personal significance for oneself, a common psychotic symptom in schizophrenia.
Delusional disorder
Delusional disorder, also called paranoid disorder, is a psychotic condition of persistent non-bizarre delusions with preserved functioning, distinct from schizophrenia; onset near age 40, prevalence 0.02–0.2%, subtypes persecutory, jealous, erotomanic, somatic.
Delusional parasitosis
Delusional parasitosis (delusional infestation, Ekbom syndrome) is a psychotic disorder with a fixed false belief of skin parasite infestation; primary, secondary, and organic forms treated with antipsychotics such as risperidone.
Deluxe
Deluxe is a six-member French band formed in 2007 in Aix-en-Provence, playing music with funk and hip-hop accents and known for its moustache symbol and logo.
Delvaux (company)
Delvaux: Belgian luxury leather goods house founded in Brussels in 1829 by Charles Delvaux; maker of the Brillant, Tempête, and Pin handbags; wholly owned by Richemont since 2021; royal purveyor to Belgium since 1883.
Delwar Hossain Sayeedi
Delwar Hossain Sayeedi (Delawar Hossain Sayedee), Jamaat-e-Islami Nayeb-e-Ameer and Islamic preacher, convicted by Bangladesh's International Crimes Tribunal in 2013 of 1971 war crimes; death sentence commuted in 2014 to life imprisonment; died in custody 14 August 2023.
Dem Rădulescu
Dem Rădulescu (Dumitru R. Rădulescu, 1931–2000), nicknamed "Bibanul", was a celebrated Romanian comedy actor of the National Theatre Bucharest, a UNATC professor, and star of films like the B.D. trilogy and O scrisoare pierdută.
Dema House
Dema House: an excavated classical Greek country house in Attica, beside the Dema Wall near Athens; dug 1958–1960 by Jones, Sackett, and Graham, published BSA 57 (1962), with pithoi storage and an andron.
Dema wall
Dema wall (Τείχος Δέμα): 4th-century BC Athenian fortification, about 4.3 km long, across the Aigaleos-Parnes pass in Attica to delay invaders from the west; distinct from a Hellenistic Dema Wall near Butrint, Albania.
Demagnetizing field
The demagnetizing field is the magnetic field generated inside a magnetized body by its own magnetization, opposing it. Described by a demagnetizing factor, it explains shape anisotropy and domain formation.