RESEARCH BASE
Search 3,721 documents across 34 fields — every claim tier-rated by evidence
3,633 are the core, quality-scored corpus (34 lettered sections — see How We Work); the remaining 88 are cross-corpus synthesis documents (68 InterDocs, 12 Connections, 8 Theories) also indexed here.
126 results for "PET scan" — page 3 of 7
ZF_5_02 — Sonar and Acoustic Ocean Sensing: Technology and Discovery
Sonar (SOund NAvigation and Ranging) is the primary technology for sensing the underwater environment — an acoustic analog to radar that exploits the fact that sound travels efficiently through water while electromagneti
ZF_5_12 — Paleocene-Eocene Thermal Maximum: Ancient Anoxic Ocean Crisis
The Paleocene-Eocene Thermal Maximum (PETM), occurring approximately 55.8 million years ago (latest Paleocene), was one of the most dramatic and rapid climate change events in the Cenozoic, offering the closest geologica
ZF_4_08 — Ocean Acidification Paleoclimate Record
Ocean acidification — the decrease in seawater pH caused by absorption of atmospheric CO₂ — is not only a modern phenomenon but has occurred repeatedly throughout Earth's history, leaving distinctive signals in the geolo
ZF_1_04 — Ocean-Climate Coupling: Paleoceanography
The ocean is Earth's primary climate regulator — absorbing ~93% of the excess heat trapped by greenhouse gases and ~30% of anthropogenic CO₂, storing 50 times more carbon than the atmosphere, and driving glacial-intergla
Z_3_13 — Horizontal Gene Transfer in Prokaryotes
Horizontal gene transfer (HGT) — the movement of genetic material between organisms outside of parent-to-offspring inheritance — is a dominant force shaping prokaryotic evolution, fundamentally challenging the traditiona
Z_1_08 — Transposons and Mobile Genetic Elements
Transposable elements (TEs, transposons) — segments of DNA that can move or copy themselves to new genomic locations — are among the most abundant and influential components of eukaryotic genomes. Discovered by Barbara M
K_1_05 — Global Workspace Theory
Global Workspace Theory (GWT), proposed by Bernard Baars (1988) and neurally formalized by Stanislas Dehaene and Jean-Pierre Changeux as the Global Neuronal Workspace (GNW, 1998–2011), is one of the leading scientific th
K_4_15 — Shared Death Experiences
Shared death experiences (SDEs) are reported phenomena in which a person who is physically healthy — typically a family member, caregiver, or bystander present at a death — describes experiencing some or all of the featu
K_2_04 — Attention and Awareness
Attention and awareness are intimately linked yet dissociable aspects of consciousness. Attention — the selective processing of some information at the expense of other information — is a fundamental bottleneck in human
K_2_21 — Transcranial Brain Stimulation: tDCS, TMS, and Deep Brain Stimulation
Transcranial brain stimulation encompasses a family of techniques that modulate neural activity by delivering energy — magnetic pulses, electrical current, or implanted electrodes — to specific brain regions. The three p
K_2_13 — Attention Networks: Dorsal, Ventral, and Salience Systems
Attention — the selective allocation of processing resources to particular stimuli, locations, or tasks — is among the most studied phenomena in cognitive neuroscience and is intimately linked to consciousness: what we a
E_3_01 — Rise and Fall of Civilizations
Every complex civilization in recorded history has collapsed or been transformed beyond recognition. The Bronze Age collapse (~1177 BCE) destroyed the interconnected civilizations of the eastern Mediterranean within a si
E_3_10 — Clathrate Gun Hypothesis
The clathrate gun hypothesis proposes that warming of ocean waters or thawing of permafrost can destabilize methane clathrates (also called methane hydrates) — ice-like crystalline structures in which methane molecules a
E_2_13 — Paleocene-Eocene Thermal Maximum
The Paleocene-Eocene Thermal Maximum (PETM) — approximately 55.8 million years ago — was the most extreme rapid warming event of the past 66 million years and is widely studied as a deep-time analog for modern anthropoge
E_1_08 — Ancient Supernovae and Their Cultural Impact
Supernovae — the explosive deaths of massive stars — are among the most energetic events in the universe, capable of briefly outshining entire galaxies. When they occur within our galaxy at distances of a few thousand li
ZG_2_07 — Dead Languages: Extinction, Documentation, and Revival
A dead language is one that no longer has any native speakers — no community transmits it to children as a first language through normal intergenerational communication. Of the approximately 7,000 languages spoken today,
ZG_5_08 — Neurolinguistics: Broca, Wernicke, Imaging, and the Language Brain
Neurolinguistics — the study of the neural basis of language — investigates how the brain represents, processes, produces, and comprehends language, drawing on evidence from brain lesions (aphasia studies), electrophysio
ZG_5_23 — Undeciphered Scripts: The World's Unsolved Writing Systems
Despite the successful decipherment of Egyptian hieroglyphs (Champollion, 1822), Mesopotamian cuneiform (Rawlinson et al., 1850s), Linear B (Ventris, 1952), and Maya glyphs (Knorozov et al., 1952–1980s), dozens of ancien
ZG_3_15 — Philosophy of Linguistics: Chomsky Debate, Innateness, and Language as Instinct
The philosophy of linguistics investigates the foundational questions that underlie the scientific study of language: What is language? Is it fundamentally a biological organ, a social convention, a cognitive skill, or a
J_3_07 — Ancient Drilling and Precision Stonework
Some of the most impressive — and most debated — achievements in ancient technology involve the drilling, cutting, and precision finishing of hard stone (granite, diorite, basalt, quartz, obsidian). Ancient civilizations
BROWSE BY SECTION — 3,721 documents across 34 fields