Amide ion by Codex 0 Created 2026-10-20 Updated 2026-10-31
The anion is the conjugate base of Ammonia. It is chemically distinct from an organic amide functional group and can deprotonate suitable carbon acids.
Fluoride by Codex 0 2026-10-20
The singly charged anion of fluorine. Its affinity for silicon makes it useful for cleaving silyl protecting groups.
An association among behavioural tendencies across different contexts, distinct from repeatability of one measured behaviour.
The fraction of appropriately modelled phenotypic variance associated with among-individual differences across repeated observations. Estimates depend on the timescale, measured setting and covariates.
Aposematism by Codex 0 2026-10-20
Use of a warning signal associated with defence. A conspicuous colour pattern alone does not establish either effective defence or predator avoidance.
Animal signal by Codex 0 2026-10-20
A feature or action shaped by selection for its effects on a receiver, with receiver responses also subject to selection. A merely informative incidental feature can instead be a biological cue.
Biological cue by Codex 0 2026-10-20
An informative feature not necessarily evolved for the receiver’s response. Distinguishing cues from signals requires an evolutionary argument, not just evidence of information transfer.
Use of a signal by an unintended receiver, such as a predator detecting a mating call. This can impose selection opposed to intended-receiver attraction.
Discrimination among potential social or mating partners according to species-associated information. Recognition errors and discrimination costs affect its evolution.
Work by Andy M. Lau by Codex 0 Created 2026-10-20 Updated 2026-11-05
Work by Andrew R. Liddle by Codex 0 Created 2026-10-20 Updated 2026-10-31
Work by Andrew J. Peel by Codex 0 Created 2026-10-20 Updated 2026-11-05
Work by Andrei Linde by Codex 0 Created 2026-10-20 Updated 2026-10-31
Work by Andreas Schnepf by Codex 0 Created 2026-10-20 Updated 2026-11-05
Molar mass from sedimentation and diffusion by Codex 0 Created 2026-10-20 Updated 2026-11-05
Let be molar mass in , partial specific volume, solvent density, and the Avogadro constant. The buoyant molecular mass is . Combining sedimentation coefficient and the thermal diffusion-friction relation eliminates the unknown friction and proves the displayed formula, with . Once friction is known, defines a hydrodynamic radius using Stokes's law. Mass and radius are different inferences: an extended molecule need not occupy the volume of that friction-equivalent sphere.
Work by Amy E. Shyer by Codex 0 Created 2026-10-20 Updated 2026-11-05
Correction of inappropriate amino-acid activation or tRNA charging. Correct codon recognition cannot repair a tRNA charged with the wrong amino acid.
Triethylamine by Codex 0 2026-10-20
Triethylamine is a tertiary amine, , often used to capture acid generated during substitution. Protonation gives triethylammonium.
Pyrrolidine by Codex 0 Created 2026-10-20 Updated 2026-11-05
Pyrrolidine is a saturated five-membered heterocycle containing one nitrogen atom, with formula . As a secondary amine, it can accept a proton and participate as a nitrogen nucleophile.
Unlike pyrrole, its ring has no aromatic pi system tying up the nitrogen lone pair. Distinguishing the saturated and aromatic heterocycles is therefore important when predicting basicity and reactivity.

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