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🔗 United States 🔗 Computing 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Iran 🔗 Computing/Software 🔗 Computing/Computer Security 🔗 Military history/Middle Eastern military history

Stuxnet is a malicious computer worm, first uncovered in 2010, thought to have been in development since at least 2005. Stuxnet targets supervisory control and data acquisition (SCADA) systems and is believed to be responsible for causing substantial damage to the nuclear program of Iran. Although neither country has openly admitted responsibility, the worm is widely understood to be a cyberweapon built jointly by the United States and Israel.

Stuxnet specifically targets programmable logic controllers (PLCs), which allow the automation of electromechanical processes such as those used to control machinery and industrial processes including gas centrifuges for separating nuclear material. Exploiting four zero-day flaws, Stuxnet functions by targeting machines using the Microsoft Windows operating system and networks, then seeking out Siemens Step7 software. Stuxnet reportedly compromised Iranian PLCs, collecting information on industrial systems and causing the fast-spinning centrifuges to tear themselves apart. Stuxnet's design and architecture are not domain-specific and it could be tailored as a platform for attacking modern supervisory control and data acquisition (SCADA) and PLC systems (e.g., in factory assembly lines or power plants), most of which are in Europe, Japan, and the US. Stuxnet reportedly ruined almost one-fifth of Iran's nuclear centrifuges. Targeting industrial control systems, the worm infected over 200,000 computers and caused 1,000 machines to physically degrade.

Stuxnet has three modules: a worm that executes all routines related to the main payload of the attack; a link file that automatically executes the propagated copies of the worm; and a rootkit component responsible for hiding all malicious files and processes, to prevent detection of Stuxnet. It is typically introduced to the target environment via an infected USB flash drive, thus crossing any air gap. The worm then propagates across the network, scanning for Siemens Step7 software on computers controlling a PLC. In the absence of either criterion, Stuxnet becomes dormant inside the computer. If both the conditions are fulfilled, Stuxnet introduces the infected rootkit onto the PLC and Step7 software, modifying the code and giving unexpected commands to the PLC while returning a loop of normal operation system values back to the users.

In 2015, Kaspersky Lab noted that the Equation Group had used two of the same zero-day attacks prior to their use in Stuxnet and commented that "the similar type of usage of both exploits together in different computer worms, at around the same time, indicates that the Equation Group and the Stuxnet developers are either the same or working closely together".

🔗 Physics

On June 28, 2009, British astrophysicist Stephen Hawking hosted a party for time travelers in the University of Cambridge. The physicist arranged for balloons, champagne, and nibbles for his guests, but did not send out the invites until the following day, after the party was over.

The party was held at the Gonville and Caius College on Trinity Street (52° 12' 21" N, 0° 7' 4.7" E) at 12:00 UT on June 28, 2009. In preparing for the event, Hawking said he hoped that copies of the invite might survive for thousands of years, and that "one day someone living in the future will find the information and use a wormhole time machine to come back to my party, proving that time travel will one day be possible".

Hawking waited in the room for a few hours before leaving, and no visitors arrived. He regarded the event as "experimental evidence that time travel is not possible".

🔗 Computing

In laptop computing, the XJACK is a type of extendable connector or antenna for a type II PC card, designed by the Megahertz subsidiary of 3Com. When not in use, the XJACK retracts into the PC card for storage.

The XJACK was originally used in modem and network cards, to attach a standard RJ11 or 8P8C plug directly to the PC card. They do not require a separate dongle, which could be lost or misplaced, and do not need to be removed from the laptop when travelling. An alternative approach is to use larger type III cards with a regular modular connector socket, but this approach requires more space.

Wi-Fi PC cards for accessing wireless networks have an external portion containing the antenna for improved reception (as compared with inside the laptop), but this portion of the card may be accidentally damaged while moving the laptop. 3Com manufactured wireless cards with retractable antenna portions, also under the XJACK name. Other companies have since manufactured wireless cards with retractable antennas.

🔗 Technology 🔗 Engineering 🔗 Sweden

The Mecanum wheel is a omnidirectional wheel design for a land-based vehicle to move in any direction. It is sometimes called the Ilon wheel after its inventor, Bengt Erland Ilon (1923-2008), who came up with the concept while working as an engineer with the Swedish company Mecanum AB, and patented it in the United States on November 13, 1972.

🔗 Korea 🔗 Food and drink 🔗 Korea/North Korea

North Korea has several restaurants serving pizza. Most people in the country cannot afford pizza, and it is mostly available for the elite. Pyongyang has five restaurants that serve pizza, including Pizza Restaurant on Kwangbok Street and Italy Pizza on Mirae Scientists Street. Kim Jong Il hired Italian chefs to train North Koreans in pizza making and introduced it to the country.

🔗 Visual arts

Iron gall ink (also known as common ink, standard ink, oak gall ink or iron gall nut ink) is a purple-black or brown-black ink made from iron salts and tannic acids from vegetable sources. It was the standard ink formulation used in Europe for the 1400-year period between the 5th and 19th centuries, remained in widespread use well into the 20th century, and is still sold today.

🔗 China 🔗 Novels 🔗 Novels/Science fiction 🔗 Science Fiction

The Dark Forest (Chinese: 黑暗森林) is a 2008 science fiction novel by the Chinese writer Liu Cixin. It is the sequel to the Hugo Award-winning novel The Three-Body Problem in the trilogy titled Remembrance of Earth's Past, but Chinese readers generally refer to the series by the title of the first novel. The English version, translated by Joel Martinsen, was published in 2015. The novel is about the dark forest hypothesis (which was named after the novel), a possible solution to the Fermi paradox, though similar theories have been described as early as 1983.

🔗 Plants

A floral formula is a notation for representing the structure of particular types of flowers. Such notations use numbers, letters and various symbols to convey significant information in a compact form. They may represent the floral form of a particular species, or may be generalized to characterize higher taxa, usually giving ranges of numbers of organs. Floral formulae are one of the two ways of describing flower structure developed during the 19th century, the other being floral diagrams. The format of floral formulae differs according to the tastes of particular authors and periods, yet they tend to convey the same information.

A floral formula is often used along with a floral diagram.

🔗 Psychology 🔗 Sociology 🔗 Media

Hofstede's cultural dimensions theory is a framework for cross-cultural psychology, developed by Geert Hofstede. It shows the effects of a society's culture on the values of its members, and how these values relate to behavior, using a structure derived from factor analysis.

Hofstede developed his original model as a result of using factor analysis to examine the results of a worldwide survey of employee values by IBM between 1967 and 1973. It has been refined since. The original theory proposed four dimensions along which cultural values could be analyzed: individualism-collectivism; uncertainty avoidance; power distance (strength of social hierarchy) and masculinity-femininity (task-orientation versus person-orientation). The Hofstede Cultural Dimensions factor analysis is based on extensive cultural preferences research conducted by Gert Jan Hofstede and his research teams. Hofstede based his research on national cultural preferences rather than individual cultural preferences. Hofstede included six key aspects of national culture country comparison scales, including: the power distance index (PDI), individualism vs. collectivism (IDV), motivation towards achievement and success (MAS, formerly masculinity versus femininity), uncertainty avoidance index (UAI), long term orientation versus short term normative orientation (LTO), and indulgence versus restraint (IVR). The PDI describes the degree to which authority is accepted and followed. The IDV measures the extent to which people look out for each other as a team or look out for themselves as an individual. MAS represents specific values that a society values. The UAI describes to what extent nations avoid the unknown. LTO expresses how societies either prioritize traditions or seek for the modern in their dealings with the present and the future. The IVR index is a comparison between a country's willingness to wait for long-term benefits by holding off on instant gratification, or preferences to no restraints on enjoying life at the present.

Independent research in Hong Kong led Hofstede to add a fifth dimension, long-term orientation, to cover aspects of values not discussed in the original paradigm. In 2010, Hofstede added a sixth dimension, indulgence versus self-restraint. Hofstede's work established a major research tradition in cross-cultural psychology and has also been drawn upon by researchers and consultants in many fields relating to international business and communication. The theory has been widely used in several fields as a paradigm for research, particularly in cross-cultural psychology, international management, and cross-cultural communication. It continues to be a major resource in cross-cultural fields.

🔗 Technology 🔗 Computing 🔗 Mathematics

A slide rule is a hand-operated mechanical calculator consisting of slidable rulers for evaluating mathematical operations such as multiplication, division, exponents, roots, logarithms, and trigonometry. It is one of the simplest analog computers.

Slide rules exist in a diverse range of styles and generally appear in a linear, circular or cylindrical form. Slide rules manufactured for specialized fields such as aviation or finance typically feature additional scales that aid in specialized calculations particular to those fields. The slide rule is closely related to nomograms used for application-specific computations. Though similar in name and appearance to a standard ruler, the slide rule is not meant to be used for measuring length or drawing straight lines. Nor is it designed for addition or subtraction, which is usually performed using other methods, like using an abacus. Maximum accuracy for standard linear slide rules is about three decimal significant digits, while scientific notation is used to keep track of the order of magnitude of results.

English mathematician and clergyman Reverend William Oughtred and others developed the slide rule in the 17th century based on the emerging work on logarithms by John Napier. It made calculations faster and less error-prone than evaluating on paper. Before the advent of the scientific pocket calculator, it was the most commonly used calculation tool in science and engineering. The slide rule's ease of use, ready availability, and low cost caused its use to continue to grow through the 1950s and 1960s, even as desktop electronic computers were gradually introduced. But after the handheld scientific calculator was introduced in 1972 and became inexpensive in the mid-1970s, slide rules became largely obsolete, so most suppliers departed the business.

In the United States, the slide rule is colloquially called a slipstick.