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A bound negative muon can be absorbed by a nucleus through the weak charged current, changing a proton into a neutron and emitting a muon neutrino. This competes with ordinary muon decay and changes the observable disappearance lifetime in a muonic atom.
A three-centre two-electron bond has two bonding electrons shared across three atomic centers. Combining three suitable atomic orbitals gives bonding, nonbonding, and antibonding combinations; occupation of the lowest combination by one electron pair can stabilize the three-center unit.
The bridging boron-hydrogen-boron interactions in diborane are the classic example. Counting each bridge as two ordinary two-center electron-pair bonds would require more electrons than are available. Multicentre bonding resolves the count while preserving a quantum-mechanical description in terms of orbitals extending across the atoms.
An electron-counting approach relating skeletal electron pairs to a cluster vertex count . A closo deltahedron has pairs; nido and arachno frameworks have and . The count excludes electrons in externally directed bonds or lone pairs. It is a structural guide with a defined domain, not a rule that every molecule with the same total valence count has the same shape.
Differentiation between reproductive and nonreproductive cell lineages. Restricting which cells found descendants can reduce transmission of some within-body competitors.
Differentiation between cell lineages contributing to future organisms and those mainly maintaining the current body. Restricting transmission routes can help align cellular reproduction with organismal reproduction.
Development of a branched tissue network through coordinated cell proliferation, shape change, cell migration and rearrangement. A final tree does not uniquely identify which cellular process generated it.
Elongation of the early fly embryonic tissue through processes including polarized junction remodelling and cell intercalation. Neighbour changes and individual cell-shape changes make separable contributions to tissue deformation.
Reduction of a cell's apical surface area, often through localized actomyosin contractility. Coordinated constriction can bend an epithelial sheet when forces are transmitted through appropriate attachments.
The epithelial invagination that internalizes prospective mesoderm during early fly development. Pulsed apical contractility and tissue coupling contribute to the movement.
The arrangement and dimensions of cells, junctions and lumina in an epithelium. Shared polarity orientation alone does not fix whether the tissue is a sheet, cyst or elongated tube.
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!
Intro to OurBigBook
. Source. We have two killer features:
- 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-calculusArticles 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/derivativeVideo 2. OurBigBook Web topics demo. Source. - 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.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 2. You can publish local OurBigBook lightweight markup files to either OurBigBook.com or as a static website.
Figure 3. Visual Studio Code extension installation.
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. 
- Infinitely deep tables of contents:
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