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🔗 Computing 🔗 Computer science 🔗 Mathematics

A* (pronounced "A-star") is a graph traversal and path search algorithm, which is often used in computer science due to its completeness, optimality, and optimal efficiency. One major practical drawback is its ${\displaystyle O(b^{d})}$ space complexity, as it stores all generated nodes in memory. Thus, in practical travel-routing systems, it is generally outperformed by algorithms which can pre-process the graph to attain better performance, as well as memory-bounded approaches; however, A* is still the best solution in many cases.

Peter Hart, Nils Nilsson and Bertram Raphael of Stanford Research Institute (now SRI International) first published the algorithm in 1968. It can be seen as an extension of Edsger Dijkstra's 1959 algorithm. A* achieves better performance by using heuristics to guide its search.

🔗 Death 🔗 Lithuania 🔗 Amusement Parks 🔗 Amusement Parks/Roller Coasters

The Euthanasia Coaster is a hypothetical steel roller coaster designed to kill its passengers. In 2010, it was designed and made into a scale model by Lithuanian artist Julijonas Urbonas, a PhD candidate at the Royal College of Art in London. Urbonas, who has worked at an amusement park, stated that the goal of his concept roller coaster is to take lives "with elegance and euphoria". As for practical applications of his design, Urbonas mentioned "euthanasia" or "execution". John Allen, who served as president of the Philadelphia Toboggan Company, inspired Urbonas with his description of the "ultimate" roller coaster as one that "sends out 24 people and they all come back dead".

🔗 Linguistics 🔗 Linguistics/Applied Linguistics

"James while John had had had had had had had had had had had a better effect on the teacher" is an English sentence used to demonstrate lexical ambiguity and the necessity of punctuation, which serves as a substitute for the intonation,stress, and pauses found in speech. In human information processing research, the sentence has been used to show how readers depend on punctuation to give sentences meaning, especially in the context of scanning across lines of text. The sentence is sometimes presented as a puzzle, where the solver must add the punctuation.

It refers to two students, James and John, required by an English test to describe a man who had suffered from a cold in the past. John writes "The man had a cold", which the teacher marks incorrect, while James writes the correct "The man had had a cold". Since James's answer was right, it had had a better effect on the teacher.

The sentence is much easier to understand with added punctuation and emphasis:

James, while John had had "had", had had "had had"; "had had" had had a better effect on the teacher.

In each of the five "had had" word pairs in the above sentence, the first of the pair is in the past perfect form. The italicized instances denote emphasis of intonation, focusing on the differences in the students' answers, then finally identifying the correct one.

🔗 Climate change 🔗 Oceans 🔗 Limnology and Oceanography

The ocean temperature varies by depth, geographical location and season. Both the temperature and salinity of ocean water differs. Warm surface water is generally saltier than the cooler deep or polar waters; in polar regions, the upper layers of ocean water are cold and fresh. Deep ocean water is cold, salty water found deep below the surface of Earth's oceans. This water has a very uniform temperature, around 0-3 °C. The ocean temperature also depends on the amount of solar radiation falling on its surface. In the tropics, with the Sun nearly overhead, the temperature of the surface layers can rise to over 30 °C (86 °F) while near the poles the temperature in equilibrium with the sea ice is about −2 °C (28 °F). There is a continuous circulation of water in the oceans. Thermohaline circulation (THC) is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. Warm surface currents cool as they move away from the tropics, and the water becomes denser and sinks. The cold water moves back towards the equator as a deep sea current, driven by changes in the temperature and density of the water, before eventually welling up again towards the surface.

Ocean temperature as a term is used either for the temperature in the ocean at any depth, or specifically for the ocean temperatures that are not near the surface (in which case it is synonymous with "deep ocean temperature").

It is clear that the oceans are warming as a result of climate change and this rate of warming is increasing.^: 9 The upper ocean (above 700 m) is warming fastest, but the warming trend extends throughout the ocean. In 2022, the global ocean was the hottest ever recorded by humans.

🔗 Mexico 🔗 Food and drink

Al pastor (from Spanish, "shepherd style"), tacos al pastor, or tacos de trompo is a preparation of spit-grilled slices of pork originating in the Central Mexican region of Puebla and Mexico City, although today it is a common menu item found in taquerías throughout Mexico. The method of preparing and cooking al pastor is based on the lamb shawarma brought by Lebanese immigrants to the region. Al pastor features a flavor palate that uses traditional Mexican adobada (marinade). It is a popular street food that has spread to the United States. In some places of northern Mexico and coastal Mexico, such as in Baja California, taco al pastor is known as taco de trompo or taco de adobada. A similar dish also from Puebla that uses a combination of middle eastern spices and indigenous central Mexican ingredients is called tacos árabes.

🔗 Aviation 🔗 Oregon 🔗 Textile Arts 🔗 Aviation/airport

The carpet at Portland International Airport (PDX) in Portland, Oregon, featured geometric shapes on a teal background, representing the intersection of the north and south runways seen by air traffic controllers from the airport's tower at night. SRG Partnership designed it in 1987, and since then, the carpet has received much media attention.

In 2013, the Port of Portland announced the carpet's replacement with a new pattern conceptualized by the Portland-based firm Zimmer Gunsul Frasca Architects. The announcement generated a social media "phenomenon" and gained attention from local and national news outlets. Removal of the original carpet began in January 2015, with the airport recycling worn portions and making remaining pieces available for sale by local retail vendors.

In 2015, Portland Trail Blazers point guard Damian Lillard released his first PDX carpet colorway on the Adidas D Lillard 1 sneaker. In 2016, Lillard released the colorway on the D Lillard 2, also inspired by the carpet.

In February of 2022, it was announced that the iconic carpet would be returning to the airport when a new terminal opens in 2024.

🔗 Internet 🔗 Hong Kong

Hong Kong Internet eXchange (HKIX; Chinese: 香港互聯網交換中心) is an internet exchange point in Hong Kong. The cooperative project is initiated by the Information Technology Services Centre (ITSC) of the Chinese University of Hong Kong (CUHK) providing the service free of charge. It is now operated by HKIX Limited, a wholly owned subsidiary of the CUHK Foundation.

The aim of the HKIX is to connect Internet service providers (ISPs) in Hong Kong so that intra-Hong Kong traffic can be exchanged locally without routing through the US or other countries. 99% internet interaction in Hong Kong goes through the centre, and HKIX acts as Hong Kong's network backbone. According to Cloudflare, HKIX is the largest internet exchange point in Asia.

🔗 Color 🔗 Visual arts

Non-photo blue (or non-repro blue) is a common tool used in the graphic design and print industry.

🔗 Aviation

A cyclorotor, cycloidal rotor, cycloidal propeller or cyclogiro, is a fluid propulsion device that converts shaft power into the acceleration of a fluid using a rotating axis perpendicular to the direction of fluid motion. It uses several blades with a spanwise axis parallel to the axis of rotation and perpendicular to the direction of fluid motion. These blades are cyclically pitched twice per revolution to produce force (thrust or lift) in any direction normal to the axis of rotation. Cyclorotors are used for propulsion, lift, and control on air and water vehicles. An aircraft using cyclorotors as the primary source of lift, propulsion, and control is known as a cyclogyro or cyclocopter. A unique aspect is that it can change the magnitude and direction of thrust without the need of tilting any aircraft structures. The patented application, used on ships with particular actuation mechanisms both mechanical or hydraulic, is named after German company Voith Turbo.

🔗 United States 🔗 Biography 🔗 California 🔗 Women scientists 🔗 Biography/science and academia 🔗 Astronomy 🔗 United States/Arizona 🔗 Solar System 🔗 California/California State University

Carolyn Jean Spellmann Shoemaker (June 24, 1929 – August 13, 2021) was an American astronomer and a co-discoverer of Comet Shoemaker–Levy 9. She once held the record for most comets discovered by an individual.

Although Shoemaker earned degrees in history, political science and English literature, she had little interest in science until she met and married geologist Eugene M. ("Gene") Shoemaker in 1950–51. She later said that his explanations of his work thrilled her. Despite her relative inexperience and lack of a science degree, California Institute of Technology (Caltech) had no objection to her joining Gene's team there as a research assistant. She had already shown herself to be unusually patient, and demonstrated exceptional stereoscopic vision, which were particularly valuable qualities for looking for objects in near-Earth space.