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🔗 Molecular and Cell Biology 🔗 Microbiology 🔗 Genetics 🔗 Citizendium Porting 🔗 Evolutionary biology

Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offspring (reproduction). HGT is an important factor in the evolution of many organisms.

Horizontal gene transfer is the primary mechanism for the spread of antibiotic resistance in bacteria, and plays an important role in the evolution of bacteria that can degrade novel compounds such as human-created pesticides and in the evolution, maintenance, and transmission of virulence. It often involves temperate bacteriophages and plasmids. Genes responsible for antibiotic resistance in one species of bacteria can be transferred to another species of bacteria through various mechanisms of HGT such as transformation, transduction and conjugation, subsequently arming the antibiotic resistant genes' recipient against antibiotics. The rapid spread of antibiotic resistance genes in this manner is becoming medically challenging to deal with. Ecological factors may also play a role in the LGT of antibiotic resistant genes. It is also postulated that HGT promotes the maintenance of a universal life biochemistry and, subsequently, the universality of the genetic code.

Most thinking in genetics has focused upon vertical transfer, but the importance of horizontal gene transfer among single-cell organisms is beginning to be acknowledged.

Gene delivery can be seen as an artificial horizontal gene transfer, and is a form of genetic engineering.

🔗 Computing 🔗 Computing/Software

Scheme 48 is a programming language, a dialect of the language Scheme, an implementation using an interpreter which emits bytecode. It has a foreign function interface for calling functions from the language C and comes with a library for regular expressions (regex), and an interface for Portable Operating System Interface (POSIX). It is supported by the portable Scheme library SLIB, and is the basis for the Scheme shell Scsh. It has been used in academic research. It is free and open-source software released under a BSD license.

It is called "Scheme 48" because the first version was written in 48 hours in August 1986. The authors now say it is intended to be understood in 48 hours.

🔗 Psychology

The psychology of music preference refers to the psychological factors behind peoples' different music preferences. Music is heard by people daily in many parts of the world, and affects people in various ways from emotion regulation to cognitive development, along with providing a means for self-expression. Music training has been shown to help improve intellectual development and ability, though no connection has been found as to how it affects emotion regulation. Numerous studies have been conducted to show that individual personality can have an effect on music preference, mostly using personality, though a recent meta-analysis has shown that personality in itself explains little variance in music preferences. These studies are not limited to American culture, as they have been conducted with significant results in countries all over the world, including Japan, Germany, and Spain.

🔗 Computing 🔗 Business 🔗 Computing/Software 🔗 Business/Accounting

VisiCalc (for "visible calculator") was the first spreadsheet computer program for personal computers, originally released for the Apple II by VisiCorp. It is often considered the application that turned the microcomputer from a hobby for computer enthusiasts into a serious business tool, prompting IBM to introduce the IBM PC two years later. VisiCalc is considered the Apple II's killer app. It sold over 700,000 copies in six years, and as many as 1 million copies over its history.

Initially developed for the Apple II using a 6502 assembler running on the Multics time sharing system, VisiCalc was ported to numerous platforms, both 8-bit and some of the early 16-bit systems. In order to do this, the company developed porting platforms that produced bug compatible versions. The company took the same approach when the IBM PC was launched, producing a product that was essentially identical to the original 8-bit Apple II version. Sales were initially brisk, with about 300,000 copies sold.

VisiCalc used the A1 notation in formulas.

When Lotus 1-2-3 was launched in 1983, taking full advantage of the expanded memory and screen of the PC, VisiCalc sales ended almost overnight. Sales declined so rapidly that the company was soon insolvent. Lotus Development purchased the company in 1985, and immediately ended sales of VisiCalc and the company's other products.

🔗 India 🔗 Time 🔗 Hinduism 🔗 Measurement

Hindu texts describe units of Kala measurements, from microseconds to Trillions of years. According to these texts, time is cyclic, which repeats itself forever.

🔗 Energy

DESERTEC was a large-scale project supported by a foundation of the same name and the consortium Dii (Desertec industrial initiative) created in Germany as a limited liability company (GmbH). The project aimed at creating a global renewable energy plan based on the concept of harnessing sustainable power from sites where renewable sources of energy are more abundant and transferring it through high-voltage direct current transmission to consumption centers. All kinds of renewable energy sources are envisioned, but the sun-rich deserts of the world play a special role.

There are some parallels between Desertec and the Atlantropa project plan in the 1920s. Atlantropa aimed to integrate Europe and Northern Africa and its electricity grid based on a giant hydro power station at Gibraltar. The industry platform Dii is continuing to pave the way for renewables and grid integration on a very pragmatic basis. As of 2019 the project is described as largely "stalled" and "failed".

🔗 Judaism

Sabbath mode, also known as Shabbos mode (Ashkenazi pronunciation) or Shabbat mode, is a feature in many modern home appliances, including ovens and refrigerators, which is intended to allow the appliances to be used (subject to various constraints) by Shabbat-observant Jews on the Shabbat and Jewish holidays. The mode usually overrides the usual, everyday operation of the electrical appliance and makes the operation of the appliance comply with the rules of Halakha (Jewish law).

🔗 Philosophy 🔗 Philosophy/Contemporary philosophy 🔗 Philosophy/Ethics

The trolley problem is a thought experiment in ethics. It is generally considered to represent a classic clash between two schools of moral thought, utilitarianism and deontological ethics. The general form of the problem is this:

There is a runaway trolley barreling down the railway tracks. Ahead, on the tracks, there are five people tied up and unable to move. The trolley is headed straight for them. You are standing some distance off in the train yard, next to a lever. If you pull this lever, the trolley will switch to a different set of tracks. However, you notice that there is one person on the side track. You have two options:

1. Do nothing and allow the trolley to kill the five people on the main track.
2. Pull the lever, diverting the trolley onto the side track where it will kill one person.

Which is the more ethical option? Or, more simply: What is the right thing to do?

Philippa Foot introduced this modern form of the problem in 1967. Judith Thomson, Frances Kamm, and Peter Unger have also analysed the dilemma extensively.

Earlier forms of the problem predated Foot's publication. Frank Chapman Sharp included a version in a moral questionnaire given to undergraduates at the University of Wisconsin in 1905. In this variation, the railway's switchman controlled the switch, and the lone individual to be sacrificed (or not) was the switchman's child. The German legal scholar Hans Welzel discussed a similar problem in 1951. In his commentary on the Talmud, published long before his death in 1953, Avrohom Yeshaya Karelitz discussed the similar question of whether it is ethical to deflect a projectile from a larger crowd toward a smaller one.

Beginning in 2001, the trolley problem and its variants have been used extensively in empirical research on moral psychology. Trolley problems have also been a topic of popular books. The problem arises in discussing the ethics of autonomous vehicle design, which may require programming to choose whom or what to strike when a collision appears to be unavoidable.

🔗 Computing

Mode X is an alternative graphics display mode of the IBM VGA graphics hardware that was popularized by Michael Abrash. It was first published in July 1991 in Dr. Dobb's Journal, and republished in chapters 47-49 of Abrash's Graphics Programming Black Book (now freely available online). The term "Mode X" was coined by Abrash.

The primary advantage of Mode X is that it has square pixels: a resolution of 320×240 instead of the standard VGA Mode 13h which is 320×200. Additionally, Abrash enabled the VGA's planar memory mode (also called "unchained mode"). Even though planar memory mode is a documented part of the VGA standard and was used in earlier commercial games, it was first widely publicized in the Mode X articles, leading many programmers to consider Mode X and planar memory synonymous. It is possible to enable planar memory in standard 320x200 mode, which became known as Mode Y in the Usenet rec.games.programmer group.

Planar memory arrangement splits the pixels horizontally into groups of four. For any given byte in PC video memory, four pixels on screen can be accessed depending on which plane(s) are enabled. This is more complicated for the programmer, but the advantages gained by this arrangement—primarily the ability to use all 256 KB of VGA memory for one or more display buffers, instead of only one quarter of that (64 KB)—were considered worthwhile by many.

🔗 Video games

Doom, a first-person shooter game by id Software, was released in December 1993 and is considered one of the most significant and influential titles in video game history. Development began in November 1992, with programmers John Carmack and John Romero, artists Adrian Carmack and Kevin Cloud, and designer Tom Hall. Late in development, Hall was replaced by Sandy Petersen and programmer Dave Taylor joined. The music and sound effects were created by Bobby Prince.

The Doom concept was proposed in late 1992, after the release of Wolfenstein 3D and its sequel Spear of Destiny. John Carmack was working on an improved 3D game engine from those games, and the team wanted to have their next game take advantage of his designs. Several ideas were proposed, including a new game in their Commander Keen series, but John proposed a game about using technology to fight demons inspired by the Dungeons & Dragons campaigns the team played. The initial months of development were spent building prototypes, while Hall created the Doom Bible, a design document for his vision of the game and its story; after id released a grandiose press release touting features that the team had not yet begun working on, the Doom Bible was rejected in favor of a plotless game with no design document at all.

Over the next six months, Hall designed levels based on real military bases, Romero built features, and artists Adrian and Cloud created textures and demons based on clay models they built. Hall's level designs, however, were deemed uninteresting and Romero began designing his own levels; Hall, increasingly frustrated with his limited influence, was fired in July. He was replaced by Petersen in September, and the team worked increasingly long hours until the game was completed in December 1993. Doom was self-published by id on December 10, 1993, and immediately downloaded by thousands of players.