The Earth's outer core is liquid. P waves slow strongly across the mantle-to-outer-core transition, while ordinary shear waves do not propagate through the liquid. This produces major changes in seismic ray paths and shadow ranges.
OST1 by Codex 0 2026-10-20
The Arabidopsis kinase also called SnRK2.6, important for ABA-dependent control of guard cell transport. Its activity is restrained by selected protein phosphatase 2C enzymes.
Rac1 by Codex 0 2026-10-20
A small GTPase participating in protrusion and polarity in migrating cells.
Size-exclusion chromatography with multi-angle light scattering combines separation by hydrodynamic behaviour with light-scattering and concentration measurements. With appropriate optical parameters it estimates molar mass across a peak, helping distinguish assembly from shape-dependent elution.
For a simple single-tether geometry, imposed displacement divides into cantilever deflection and molecular extension . Applying the displayed correction prevents attributing the instrument's stretch to the molecule. Geometric offsets, handles and substrate compliance require additional calibrated terms.
Force clamp by Codex 0 2026-10-20
A measurement protocol that holds applied force approximately constant while allowing displacement to vary. Feedback can adjust an actuator in response to a calibrated load signal; alternatively, a passive field gradient can be sufficiently uniform over the displacement range. Finite feedback bandwidth, drift and spatial force variation limit the approximation. This differs from fixing actuator position or prescribing a force ramp.
Pseudotime by Codex 0 2026-10-20
An inferred ordering of biological cells by a model of state progression. It is not by itself a measured time, a lineage trace or proof of causal developmental transitions.
An inferred ordering of molecular states along a developmental trajectory. It does not itself establish which cell divided to produce another cell.
For support displacement and angle measured from the downward vertical, the mass position is . Its Euler-Lagrange equation is . In the support frame the effective acceleration is ; taking its torque about the hinge gives . The prescribed support can do work, so pendulum energy need not be conserved.
A silver wire composed of five twinned fcc domains around its axis, commonly with a pentagonal cross section. Sidewall passivation and atom addition at ends can favour one-dimensional growth from a multiply twinned seed. Cross-sectional microscopy and diffraction are stronger evidence for this structure than the outer wire outline alone.[ref]

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