Fritz Strassmann was a German physicist who is best known for his work in nuclear chemistry and for his role in the discovery of nuclear fission. He was born on February 22, 1902, and passed away on April 22, 1980.
In physics, symmetry refers to a property or characteristic of a system that remains invariant under certain transformations. This can involve spatial transformations, such as translations, rotations, and reflections, as well as other types such as time reversibility or particle interchange. Symmetry plays a critical role in understanding physical laws and phenomena, often leading to conservation laws and simplifying complex problems.
riscv/timer.S by Ciro Santilli 40 Updated 2025-07-16
Tested on Ubuntu 23.10:
sudo apt install binutils-riscv64-unknown-elf qemu-system-misc gdb-multiarch
cd riscv
make
Then on shell 1:
qemu-system-riscv64 -machine virt -cpu rv64 -smp 1 -s -S -nographic -bios none -kernel timer.elf
and on shell 2:
gdb-multiarch timer.elf -nh -ex "target remote :1234" -ex 'display /i $pc' -ex 'break *mtrap' -ex 'display *0x2004000' -ex 'display *0x200BFF8'
GDB should break infinitel many times on mtrap as interrupts happen.
In v4.2, look under arch/x86/:
  • include/asm/pgtable*
  • include/asm/page*
  • mm/pgtable*
  • mm/page*
There seems to be no structs defined to represent the pages, only macros: include/asm/page_types.h is specially interesting. Excerpt:
#define _PAGE_BIT_PRESENT   0   /* is present */
#define _PAGE_BIT_RW        1   /* writeable */
#define _PAGE_BIT_USER      2   /* userspace addressable */
#define _PAGE_BIT_PWT       3   /* page write through */
arch/x86/include/uapi/asm/processor-flags.h defines CR0, and in particular the PG bit position:
#define X86_CR0_PG_BIT      31 /* Paging */
Paleolithic by Ciro Santilli 40 Updated 2025-07-16
This period is similar to the Quaternary, but it also includes tool usage by close relatives of humans which were not humans yet.
It ends together with the pleistocene.
One reasonable and memorable approximation excluding any fine structure is:
Equation 1.
Hydrogen spectral series mnemonic
.
see for example example: hydrogen 1-2 spectral line.
A pasquinade is a form of satirical writing or public ridicule, often presented in the form of a poem, poster, or other written material that is displayed in a public place. Traditionally, pasquinades were used to criticize or mock public figures, political issues, or societal norms.
The 20th century was a transformative period for mathematics, characterized by significant developments across various fields, including pure and applied mathematics. Here are some key highlights: 1. **Foundations and Logic**: The early 20th century saw a focus on the foundations of mathematics, particularly through the work of mathematicians like David Hilbert, Kurt Gödel, and Bertrand Russell.
Mathematics museums are specialized institutions that focus on the presentation, exploration, and celebration of mathematical concepts, history, and applications. These museums seek to engage visitors of all ages with mathematical ideas through interactive exhibits, educational programs, and often, hands-on activities. The goal is to promote a better understanding of mathematics as both an abstract field of study and a practical tool that affects everyday life.
Statistics educators are individuals who specialize in teaching and facilitating the learning of statistics at various educational levels, from elementary education to higher education. They play a crucial role in helping students understand statistical concepts, methods, and applications, and they aim to develop students' ability to critically evaluate data and make data-driven decisions. The role of statistics educators can involve: 1. **Curriculum Development**: Designing and implementing curricula that effectively teach statistical principles and practices.

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 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . 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.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  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