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🔗 United States 🔗 Architecture 🔗 Skyscrapers 🔗 United States/Texas 🔗 National Register of Historic Places

The Newby–McMahon Building, commonly referred to as the world's littlest skyscraper, is located at 701 La Salle (on the corner of Seventh and La Salle streets) in downtown Wichita Falls, Texas. It is a late Neoclassical style red brick and cast stone structure. It stands 40 ft (12 m) tall, and its exterior dimensions are 18 ft (5.5 m) deep and 10 ft (3.0 m) wide. Its interior dimensions are approximately 12 ft (3.7 m) by 9 ft (2.7 m), or approximately 108 sq ft (10.0 m²). Steep, narrow, internal stairways leading to the upper floors occupy roughly 25 percent of the interior area.

Reportedly the result of a fraudulent investment scheme by a confidence man, the Newby–McMahon Building was a source of great embarrassment to the city and its residents after its completion in 1919. During the 1920s, the Newby–McMahon Building was featured in Robert Ripley's Ripley's Believe It or Not! syndicated column as "the world's littlest skyscraper," a nickname that has stuck with it ever since. The Newby–McMahon Building is now part of the Depot Square Historic District of Wichita Falls, a Texas Historic Landmark.

🔗 Africa 🔗 Water 🔗 Rivers 🔗 Africa/Libya

The Great Man-Made River (GMMR, النهر الصناعي العظيم) is a network of pipes that supplies fresh water obtained from the Nubian Sandstone Aquifer System fossil aquifer across Libya. It is the world's largest irrigation project. The project utilizes a pipeline system that pumps water from the Nubian Sandstone Aquifer System from down south in Libya to cities in the populous Libyan northern Mediterranean coast including Tripoli and Benghazi. The water covers a distance of up to 1,600 kilometers and provides 70% of all freshwater used in Libya.

According to its website, it is the largest underground network of pipes (2,820 kilometres (1,750 mi)) and aqueducts in the world. It consists of more than 1,300 wells, most more than 500 m deep, and supplies 6,500,000 m³ of fresh water per day to the cities of Tripoli, Benghazi, Sirte and elsewhere. The late Libyan Leader Muammar Gaddafi described it as the "Eighth Wonder of the World".

🔗 Companies 🔗 Environment 🔗 Automobiles

Criticism of Tesla, Inc., especially under CEO Elon Musk, ranges from potential safety issues to questionable business practices which include alleged fraud, a history of environmental violations, disregard for workers' safety, and Musk's excessive compensation package. Tesla and Musk have also been criticized for their attempts to intimidate and silence whistleblowers, journalists, and other critics who have spoken out against the company.

🔗 Military history 🔗 Religion 🔗 Anthropology 🔗 Sociology 🔗 Archaeology 🔗 Mythology 🔗 Military history/Military culture, traditions, and heraldry

The kóryos (Proto-Indo-European: "army, people under arms" or "detachment, war party") refers to the hypothetical Proto-Indo-European brotherhood of warriors in which unmarried young males served for a number of years before their full integration to the host society, in the context of a rite of passage into manhood.

Subsequent Indo-European traditions and myths feature parallel linkages between property-less adolescent males, perceived as an age-class not yet fully integrated into the community of the married men; their service in a "police-army" sent away for a part of the year in the wild (where they hunted animals and raided foreign communities) and defending the host society during the remaining part of the year; their mystical self-identification with wolves and dogs as symbols of death, promiscuity, lawlessness, and warrior fury; and the idea of a liminality between invulnerability and death on one side, and youth and adulthood on the other side.

🔗 Climate change 🔗 Europe 🔗 Energy

The European super grid is a possible future super grid that would ultimately interconnect the various European countries and the regions around Europe's borders – including North Africa, Kazakhstan, and Turkey – with a high-voltage direct current (HVDC) power grid.

It is envisaged that a European super grid would:

• lower the cost of power in all participating countries by allowing the entire region to share the most efficient power plants;
• pool load variability and power station unreliability, reducing the margin of inefficient spinning reserve and standby that have to be supplied;
• allow for wider use of renewable energy, particularly wind energy, from the concept that "it is always windy somewhere" – in particular it tends to be windy in the summer in North Africa, and windy in the winter in Europe;
• allow wide sharing of the total European hydro power resource, which is about 6 weeks of full load European output;
• decrease Europe's dependence on imported fuels.

🔗 Brands 🔗 Toys

Spirograph is a geometric drawing device that produces mathematical roulette curves of the variety technically known as hypotrochoids and epitrochoids. The well known toy version was developed by British engineer Denys Fisher and first sold in 1965.

The name has been a registered trademark of Hasbro Inc. since 1998 following purchase of the company that had acquired the Denys Fisher company. The Spirograph brand was relaunched worldwide in 2013, with its original product configurations, by Kahootz Toys.

🔗 Video games 🔗 Lists

This is a list of video games that multiple video game journalists and critics have considered to be among the best of all time. The games listed here are included on at least six separate "best/greatest of all time" lists from different publications, as chosen by their editorial staffs.

🔗 Statistics 🔗 Futures studies

The Delphi method or Delphi technique ( DEL-fy; also known as Estimate-Talk-Estimate or ETE) is a structured communication technique or method, originally developed as a systematic, interactive forecasting method which relies on a panel of experts. The technique can also be adapted for use in face-to-face meetings, and is then called mini-Delphi or Estimate-Talk-Estimate (ETE). Delphi has been widely used for business forecasting and has certain advantages over another structured forecasting approach, prediction markets.

Delphi is based on the principle that forecasts (or decisions) from a structured group of individuals are more accurate than those from unstructured groups. The experts answer questionnaires in two or more rounds. After each round, a facilitator or change agent provides an anonymised summary of the experts' forecasts from the previous round as well as the reasons they provided for their judgments. Thus, experts are encouraged to revise their earlier answers in light of the replies of other members of their panel. It is believed that during this process the range of the answers will decrease and the group will converge towards the "correct" answer. Finally, the process is stopped after a predefined stop criterion (e.g., number of rounds, achievement of consensus, stability of results), and the mean or median scores of the final rounds determine the results.

Special attention has to be paid to the formulation of the Delphi theses and the definition and selection of the experts in order to avoid methodological weaknesses that severely threaten the validity and reliability of the results.

🔗 Mathematics 🔗 Statistics 🔗 Systems 🔗 Robotics 🔗 Systems/Control theory

In statistics and control theory, Kalman filtering, also known as linear quadratic estimation (LQE), is an algorithm that uses a series of measurements observed over time, containing statistical noise and other inaccuracies, and produces estimates of unknown variables that tend to be more accurate than those based on a single measurement alone, by estimating a joint probability distribution over the variables for each timeframe. The filter is named after Rudolf E. Kálmán, one of the primary developers of its theory.

The Kalman filter has numerous applications in technology. A common application is for guidance, navigation, and control of vehicles, particularly aircraft, spacecraft and dynamically positioned ships. Furthermore, the Kalman filter is a widely applied concept in time series analysis used in fields such as signal processing and econometrics. Kalman filters also are one of the main topics in the field of robotic motion planning and control and can be used in trajectory optimization. The Kalman filter also works for modeling the central nervous system's control of movement. Due to the time delay between issuing motor commands and receiving sensory feedback, use of the Kalman filter supports a realistic model for making estimates of the current state of the motor system and issuing updated commands.

The algorithm works in a two-step process. In the prediction step, the Kalman filter produces estimates of the current state variables, along with their uncertainties. Once the outcome of the next measurement (necessarily corrupted with some amount of error, including random noise) is observed, these estimates are updated using a weighted average, with more weight being given to estimates with higher certainty. The algorithm is recursive. It can run in real time, using only the present input measurements and the previously calculated state and its uncertainty matrix; no additional past information is required.

Optimality of the Kalman filter assumes that the errors are Gaussian. In the words of Rudolf E. Kálmán: "In summary, the following assumptions are made about random processes: Physical random phenomena may be thought of as due to primary random sources exciting dynamic systems. The primary sources are assumed to be independent gaussian random processes with zero mean; the dynamic systems will be linear." Though regardless of Gaussianity, if the process and measurement covariances are known, the Kalman filter is the best possible linear estimator in the minimum mean-square-error sense.

Extensions and generalizations to the method have also been developed, such as the extended Kalman filter and the unscented Kalman filter which work on nonlinear systems. The underlying model is a hidden Markov model where the state space of the latent variables is continuous and all latent and observed variables have Gaussian distributions. Also, Kalman filter has been successfully used in multi-sensor fusion, and distributed sensor networks to develop distributed or consensus Kalman filter.

🔗 Physics 🔗 Physics/relativity

In astrophysics, spaghettification (sometimes referred to as the noodle effect) is the vertical stretching and horizontal compression of objects into long thin shapes (rather like spaghetti) in a very strong non-homogeneous gravitational field; it is caused by extreme tidal forces. In the most extreme cases, near black holes, the stretching is so powerful that no object can withstand it, no matter how strong its components. Within a small region the horizontal compression balances the vertical stretching so that small objects being spaghettified experience no net change in volume.

Stephen Hawking described the flight of a fictional astronaut who, passing within a black hole's event horizon, is "stretched like spaghetti" by the gravitational gradient (difference in strength) from head to toe. The reason this happens would be that the gravity force exerted by the singularity would be much stronger at one end of the body than the other. If one were to fall into a black hole feet first, the gravity at their feet would be much stronger than at their head, causing the person to be vertically stretched. Along with that, the right side of the body will be pulled to the left, and the left side of the body will be pulled to the right, horizontally compressing the person. However, the term "spaghettification" was established well before this. Spaghettification of a star was imaged for the first time in 2018 by researchers observing a pair of colliding galaxies approximately 150 million light-years from Earth.