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Experiments on the Effect of a Current of Electricity on the Magnetic Needle by Hans Christian Ørsted by 
Codex 0 2026-11-05
Codex 0 2026-11-05Original announcement dated 21 July 1820; English historical translation inspected, first experiments and requirement for a complete circuit. Check subsequent text pages before detailed above/below-wire statements.
Reconstructed Wavefronts and Communication Theory by Emmett Leith and Juris Upatnieks by Codex 0 2026-11-05
Codex 0 2026-11-05Institutional description of the LISE optical workshop. No publication date inferred from the crawl date or the page's use of the present tense.
Official indexed text inspected: identifies David Vernet as workshop head, describes optical fabrication for C2PU and two one-metre telescopes, and captions polishing the first 1.04-metre primary mirror. The personal article attributes these statements to the institutional description rather than asserting a current job appointment.
On the Diffraction of an Object-glass with Circular Aperture by George Biddell Airy by Codex 0 2026-11-05
Codex 0 2026-11-05Original paper reproduced in the appendix of this annotated document: violetzebra3.sakura.ne.jp/airyR1.pdf
Transactions of the Cambridge Philosophical Society 5, 283–291. Cited for the circular-aperture diffraction calculation; the modern introductory commentary is distinct from the reproduced original paper.
NASA Jet Propulsion Laboratory education activity. Materials and steps 2–7 describe two cards, pierced foil, projection onto the receiving card and the effect of changing the card separation.
Die wahrscheinliche Schwingungsverteilung in einer von einer Lichtquelle direkt oder mittels einer Linse beleuchteten Ebene by Pieter Hendrik van Cittert by Codex 0 2026-11-05
Codex 0 2026-11-05Physica 1, 201–210. Original coherence-theory paper.
Manufacturer glossary: low-energy secondary-electron emission, surface sensitivity and secondary signals excited away from the primary probe position.
Manufacturer glossary: origin of backscattered electrons, their energy relative to secondary electrons, and composition and channeling effects.
Institutional account published by the University of Rochester: www.rochester.edu/news/printable.php?id=1288
Total Internal Reflection Fluorescence Microscopy by University of California San Francisco by Codex 0 2026-11-05
Codex 0 2026-11-05Institutional technique description: microscopy.ucsf.edu/content/total-internal-reflection-fluorescence-microscopy-tirf
Describes evanescent-field excitation near a coverslip and its use for surface-associated fluorescence imaging.
University laboratory course notes: byucamacholab.github.io/nonlinear-optics/pages/3.%20Overview%20of%20Nonlinear%20Processes.html
The sum- and difference-frequency section relates the quadratic field response to frequency conversion and parametric amplification.
Manufacturer tutorial: www.microscopyu.com/techniques/stereomicroscopy/darkfield-illumination
Manufacturer tutorial: www.microscopyu.com/techniques/dic/specimen-contrast-in-optical-microscopy
Figures 1 and 6 compare contrast methods and describe sheared polarized beams in differential interference contrast.
Institutional laboratory procedure: microscopy.duke.edu/kohler-illumination-procedure
Mathematics achievement is attained performance on specified mathematical learning objectives. Its meaning depends on the content and scoring of the assessment: proficiency in counting, arithmetic and geometry need not form an identical profile. A total score can summarize performance while concealing which skills changed.
An informative intervention therefore measures more than success on its practiced activity. In Geetha B. Ramani's study with Robert S. Siegler, children played either a linear numbered board game or a corresponding color board game. Assessment included counting, numeral identification, numerical magnitude comparison and number-line estimation, rather than only skill at winning the game.[ref]
Promoting broad and stable improvements in low-income children's numerical knowledge through playing number board games by Geetha B. Ramani and others. 2008, abstract; Materials and Procedure; numerical knowledge measures
Improvement on an assessment is evidence about that outcome in the studied population. Claims about broader mathematical understanding require appropriate generalization tests and a comparison design that separates the intervention from maturation, repeated testing and other experiences.
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