Acute disease by Codex 0 2026-10-31
A disease with a relatively rapid onset or short course, in contrast to a chronic disease. Ancient authors used their own classifications; their boundaries need not match modern ones.
Coeliac disease by Codex 0 Created 2026-10-31 Updated 2026-11-05
A chronic disease in which an immune response triggered by gluten damages the small intestine. The modern definition must not simply be read back into the coeliac affection of Aretaeus. [ref]
Malabsorption by Codex 0 Created 2026-10-31 Updated 2026-11-05
Impaired uptake of nutrients from the digestive tract. Defective digestion and damage to absorptive surfaces are different routes to reduced nutrient availability despite adequate food intake.
Diarrhoea by Codex 0 2026-10-31
Passage of loose or watery material from the intestine; a description of a symptom rather than identification of its cause.
Nosebleed by Codex 0 2026-10-31
Loss of blood through the nose; a descriptive event, not by itself identification of a disease.
Anaemia by Codex 0 Created 2026-10-31 Updated 2026-11-05
A reduction in blood oxygen-carrying capacity reflected in hemoglobin below the appropriate reference threshold. Reduced production, increased destruction and blood loss are different mechanisms of the same broad finding.
Haemochromatosis by Codex 0 2026-10-31
A condition involving excessive accumulation of iron. Venesection removes iron within red blood cells and stimulates use of further iron in their replacement. [ref]
Uraemia by Codex 0 Created 2026-10-31 Updated 2026-11-05
A clinical syndrome associated with severe loss of renal function and retention of normally excreted substances. It is broader than an isolated laboratory elevation of urea.
Obesity by Codex 0 Created 2026-10-31 Updated 2026-11-05
Excess accumulation of body fat associated with adverse health effects. Body-mass measures can support population assessment, while fat distribution and individual metabolic function provide additional information.
Liver disease by Codex 0 Created 2026-10-31 Updated 2026-11-05
A disorder affecting the structure or function of the liver. Damage to cells, impaired bile flow and altered blood circulation can produce different patterns despite sharing an organ.
Producing a valid digital signature on some new message under the specified attack model, without necessarily controlling that message's content in advance.
Universal forgery by Codex 0 2026-10-31
The ability to produce a valid digital signature for an arbitrary specified target message. Under a chosen-message signature attack, the target must not have been submitted to the signing oracle.
A digital signature attack using the public scheme and verification public key, without supplied signed-message examples or a signing oracle.
A digital signature attack using legitimate message–signature pairs whose messages were not selected by the adversary.
A digital signature attack with a signing oracle for adversary-selected messages. A forgery must authenticate a message not previously submitted to that oracle.
Vomiting by Codex 0 Created 2026-10-31 Updated 2026-11-05
Vomiting is the coordinated expulsion of upper digestive contents through the mouth. Neural control recruits digestive, respiratory and abdominal mechanisms. It is distinct from the sensation of nausea and from retching, which can occur without expulsion.
Bile by Codex 0 Created 2026-10-31 Updated 2026-11-05
Bile is a secretion produced by the liver and delivered to the intestine, with storage in the gallbladder in species that possess one. Its bile salts support lipid handling, while pigments and other components contribute excretory functions. It is a mixture rather than one digestive enzyme.
Digestion by Codex 0 2026-10-31
Processing food into forms suitable for use by an organism. Historical explanations by digestive heat must be distinguished from modern physiology.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact