Quadratic form Updated 2025-07-16
Multivariate polynomial where each term has degree 2, e.g.:is a quadratic form because each term has degree 2:but e.g.:is not because the term has degree 3.
There is a 1-to-1 relationship between quadratic forms and symmetric bilinear forms. In matrix representation, this can be written as:where contains each of the variabes of the form, e.g. for 2 variables:
Strictly speaking, the associated bilinear form would not need to be a symmetric bilinear form, at least for the real numbers or complex numbers which are commutative. E.g.:But that same matrix could also be written in symmetric form as:so why not I guess, its simpler/more restricted.
JavaScript browser example Updated 2025-07-16
- js/confirm-close.html: stackoverflow.com/questions/7317273/warn-user-before-leaving-web-page-with-unsaved-changes
- web-cheat/js-image-load.html: load an image from JavaScript dynamically: stackoverflow.com/questions/226847/what-is-the-best-javascript-code-to-create-an-img-element
- web-cheat/js-image-load-viewport.html: load an image from JavaScript dynamically when it would become visible on the viewport: stackoverflow.com/questions/2321907/how-do-you-make-images-load-only-when-they-are-in-the-viewport
- html/img-load-lazy.html: stackoverflow.com/questions/2321907/how-do-you-make-images-load-lazily-only-when-they-are-in-the-viewport/57389607#57389607
- web-cheat/esm.html: ESM modules
- js/keydown.html: stackoverflow.com/questions/16006583/capturing-ctrlz-key-combination-in-javascript
External libraries
- Text editors
- Interactive HTML table sorting
Jazz fusion band Updated 2025-07-16
JCVI-syn3A Updated 2025-07-16
Based on JCVI-syn3.0, they've added a few genes back to give better phenotypes, including slightly faster duplication time. Because the development cycle time is your God is also true in biology.
As of essential metabolism for a minimal cell (2019) it had only 91 genes of unknown function! So funny.
Bibliograpy:
JCVI-syn3A during cell division by David Goodsell (2022)
Source. A description is present at: cdn.rcsb.org/pdb101/goodsell/2022_JCVI-syn3A.pdf Integrative Illustration of a JCVI-syn3A Minimal Cell by David Goodsell (2022) which describes everything in the picture. Ciro Santilli's hardware Lenovo ThinkPad P51 (2017) log Updated 2025-07-16
- battery life:
- 2023-04: on-browser streaming + light browsing on Ubuntu 22.10: about 2h45. Too low! Gotta try buying a new battery.
- 2022-01-04 updated firmward after noticing that ubuntu 21.10 does not wake up from suspend seemed to happen every time when not connected to external power.
dmidecodediff excerpt:used the "Ubuntu Software" GUI as mentioned at: support.lenovo.com/gb/en/solutions/ht510810-how-to-do-software-updates-linux. Kudos for making this accessible to newbs.BIOS Information Vendor: LENOVO - Version: N1UET40W (1.14 ) - Release Date: 09/28/2017 + Version: N1UET71W (1.45 ) + Release Date: 07/18/2018After doing that, another update became available to: 0.1.56, clicked it and was much faster than the previous one, and didn't auto reboot. After manual reboot,dmidecodediffed again:plus a bunch of other lines.BIOS Information Vendor: LENOVO - Version: N1UET71W (1.45 ) - Release Date: 07/18/2018 + Version: N1UET82W (1.56 ) + Release Date: 08/12/2021 - 2021-06-05 upgraded to Ubuntu 21.04 with a clean install from an ISO. SelectedAfter this, the GUI felt fast, who would have thought that erasing a bunch of stuff would make the system faster!
- "Minimal installation"
- "Erase disk and install Ubuntu". Notably, this erased the Microsoft Windows that came with the computer and was never used not even once
- "Erase disk ans use ZFS"
- Encrypt the new Ubuntu installation for security
lsblkcontains:andzd0 230:0 0 500M 0 disk └─keystore-rpool 253:0 0 484M 0 crypt /run/keystore/rpool nvme0n1 259:0 0 476.9G 0 disk ├─nvme0n1p1 259:1 0 512M 0 part /boot/efi ├─nvme0n1p2 259:2 0 2G 0 part │ └─cryptoswap 253:1 0 2G 0 crypt ├─nvme0n1p3 259:3 0 2G 0 part └─nvme0n1p4 259:4 0 472.4G 0 partlsblk -f:zd0 crypto_LUKS 2 └─keystore-rpool ext4 1.0 keystore-rpool nvme0n1 ├─nvme0n1p1 vfat FAT32 ├─nvme0n1p2 crypto_LUKS 2 │ └─cryptoswap ├─nvme0n1p3 zfs_member 5000 bpool └─nvme0n1p4 zfs_member 5000 rpooThen:contains:grep '[rb]pool' /proc/mountswhich gives an idea of how the above map to mountpoints.rpool/ROOT/ubuntu_uvs1fq / zfs rw,relatime,xattr,posixacl 0 0 rpool/USERDATA/ciro_czngbg /home/ciro zfs rw,relatime,xattr,posixacl 0 0 rpool/USERDATA/root_czngbg /root zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/srv /srv zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/usr/local /usr/local zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/games /var/games zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/log /var/log zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/lib /var/lib zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/mail /var/mail zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/snap /var/snap zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/www /var/www zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/spool /var/spool zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/lib/AccountsService /var/lib/AccountsService zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/lib/NetworkManager /var/lib/NetworkManager zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/lib/apt /var/lib/apt zfs rw,relatime,xattr,posixacl 0 0 rpool/ROOT/ubuntu_uvs1fq/var/lib/dpkg /var/lib/dpkg zfs rw,relatime,xattr,posixacl 0 0 bpool/BOOT/ubuntu_uvs1fq /boot zfs rw,nodev,relatime,xattr,posixacl 0 0
2020-06-06: dropped some lemon juice on the bottom left of touchpad. Bottom left button not working anymore... I'm an idiot. There are many other alternatives, but very aggravating, I'll replace it for sure. Can't find the exact replacement part or any videos showing its replacement online easliy, dang. For the T430: www.youtube.com/watch?v=F3lzV9uXRjU Asked at: forums.lenovo.com/t5/ThinkPad-P-and-W-Series-Mobile-Workstations/P51-left-bottom-button-below-trackpad-mouse-left-click-stopped-working-possible-to-replace/m-p/5019903 Also I could not access it because you need to remove the HDD first: www.youtube.com/watch?v=5Klawxc7T_Y and I can't pull it out even with considerable force, unlike in the video... And OMG, those button caps are impossible to re-install once removed!!! Then when I put the whole thing back together, the upper buttons were not working anymore. FUUUUUUUUCK. When first opening I pulled on it without properly removing the cap and it came off, but it didn't look broken in any way and I put it back in. Keyboard works thank God, so right black connector is fine, left white one oppears to be the one for upper keys and trackpoint, both of which stopped working. The hardware manual confirms that they are both part of the same device, so basically a mouse :-) TODO can it be bought separately from te keyboard? Doesn't look like it, photo of keyboard part includes those buttons. The manual also confirms that the bottom buttons are one device with the trackpad "trackpad with buttons", thus forming the second entire mouse.
2019-04-17: popup asking about "ThinkPad P51 Management Engine Update" from from 182.29.3287 to 184.60.3561, said yes.
- partition setup: askubuntu.com/questions/343268/how-to-use-manual-partitioning-during-installation/976430#976430
- BIOS:
- for NVIDIA driver:
- for KVM, required by Android Emulator: enable virtualization extensions
- TODO fix the brightness keys:
JCVI-syn3B Updated 2025-07-16
www.biorxiv.org/content/10.1101/2022.09.19.508583v1.fullIt is also interesting to see how they are interested in co-culture with HeLa cells, presumably to enable infectious bacterial disease studies.
CVI-syn3B strains differ from JCVI-syn3.0 by the presence of 19 additional non-essential genes that result in a more easily manipulated cell. JCVI-syn3B additionally includes a dual loxP landing pad that enables easy Cre recombinase mediated insertion of genes
At biology.indiana.edu/news-events/news/2023/lennon-minimal-cells.html (2023) they let it re-evove to it it would regain some fitness, and it did.
Eigendecomposition of a real symmetric matrix Updated 2025-07-16
The general result from eigendecomposition of a matrix:becomes:where is an orthogonal matrix, and therefore has .
Jean-Luc Ponty Updated 2025-07-16
Jekyll (software) Updated 2025-07-16
E Ink Updated 2025-07-16
Electronic Ink such as that found on Amazon Kindle is the greatest invention ever made by man.
Once E Ink reaches reasonable refresh rates to replace liquid crystal displays, the world will finally be saved.
It would allow Ciro Santilli to spend his entire life in front of a screen rather in the real world without getting tired eyes, and even if it is sunny outside.
Ciro stopped reading non-code non-news a while back though, so the current refresh rates are useless, what a shame.
OMG, this is amazing: getfreewrite.com/
Jerry Sanders Updated 2025-07-16
AMD Founder Jerry Sanders Interview (2002)
Source. Source: exhibits.stanford.edu/silicongenesis/catalog/hr396zc0393. Fun to watch.- youtu.be/HqWWoaA8pIs?t=779 Newton Minow mandated UHF on all television sets in 1961, and the oscillator needed for the tuner was one of the first major non-military products from Fairchild, the 28918 (?).
- youtu.be/HqWWoaA8pIs?t=1053 Fairchild had won the first round of a Minuteman contract, but lost the second one due to poor management
Jim Baggott selects the topics for his books by writing about things he wants to know more about Updated 2025-07-16
Mentinoned at en.wikipedia.org/wiki/Jim_Baggott quoting popsciencebooks.blogspot.com/2012/09/jim-baggott-four-way-interview.html
Ciro Santilli and Jim would get along mighty well: there is value in tutorials written by beginners.
Jimmy Wales Updated 2025-07-16
Jim Simons Updated 2025-07-16
Ciro Santilli's wife, who was frustrated with academia at some point, admires the fact that Simons managed to make infinite money, and then invested back in actual science, e.g. through the Simons Foundation.
Jim Simons in 2007
. John Bardeen Updated 2025-07-16
The Story of John Bardeen at the University of Illinois (2010)
Source. - youtu.be/OyV8qSwGUHU?t=976 of when Bardeen demoed the transistor in class is particularly memorable
- youtu.be/OyV8qSwGUHU?t=1105 some of his golf colleagues didn't know he had won a Nobel Prize!
Josephson effect Updated 2025-07-16
Discrete quantum effect observed in superconductors with a small insulating layer, a device known as a Josephson junction.
To understand the behaviour effect, it is important to look at the Josephson equations consider the following Josephson effect regimes separately:
Bibliography:
- www.youtube.com/watch?v=cnZ6exn2CkE "Superconductivity: Professor Brian Josephson". Several random excerpts from Cambridge people talking about the Josephson effect
Josephson equations Updated 2025-07-16
Two equations derived from first principles by Brian Josephson that characterize the device, somewhat like an I-V curve:where:
- : Josephson current
- : the Josephson phase, a function defined by the second equation plus initial conditions
- : input voltage of the system
- : current across the junction, determined by the input voltage
Note how these equations are not a typical I-V curve, as they are not an instantaneous dependency between voltage and current: the history of the voltage matters! Or in other words, the system has an internal state, represented by the Josephson phase at a given point in time.
To understand them better, it is important to look at some important cases separately:
- AC Josephson effect: V is a fixed DC voltage
Josephson junction Updated 2025-07-16
Quantum computer physical implementation Updated 2025-07-16
Lists of the most promising implementations:
As of 2020, the hottest by far are:
Super quick overview of the main types of quantum computer physical implementations, so doesn't any much to a quick Google.
He says he's going to make a series about it, so then something useful might actually come out. The first one was: Video "How to Turn Superconductors Into A Quantum Computer by Lukas's Lab (2023)", but it is still too basic.
The author's full name is Lukas Baker, www.linkedin.com/in/lukasbaker1331/, found with Google reverse image search, even though the LinkedIn image is very slightly different from the YouTube one.
Archaea Updated 2025-07-16
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