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🔗 Central America 🔗 Panama 🔗 Colombia

The Darién Gap (UK: , US: , Spanish: Tapón del Darién [taˈpon del daˈɾjen], lit. 'Darién plug') is a geographic region in the Isthmus of Darien or Isthmus of Panama connecting the American continents within Central America, consisting of a large watershed, forest, and mountains in Panama's Darién Province and the northern portion of Colombia's Chocó Department.

The "Gap" interrupts the Pan-American Highway. Some 106 km (66 mi) of this between Yaviza, Panama, and Turbo, Colombia, has never been built. Road-building in this area is both expensive and detrimental to the environment. Political consensus in favor of road construction collapsed after an initial attempt failed in the early 1970s, with a proposal in the early 1990s halted by environmental concerns. As of 2023, there was no active plan to build a road through the Gap, although there has been discussion of reestablishing a ferry service.

The geography of the Darién Gap on the Colombian side is dominated primarily by the river delta of the Atrato River, which creates a flat marshland at least 80 km (50 mi) wide. The Serranía del Baudó range extends along Colombia's Pacific coast and into Panama. The Panamanian side, in stark contrast, is a mountainous rainforest, with terrain reaching from 60 m (197 ft) in the valley floors to 1,845 m (6,053 ft) at the tallest peak (Cerro Tacarcuna, in the Serranía del Darién).

The Darién Gap is home to the Embera-Wounaan and Guna people and was also home to the Cueva people who became extinct by 1535, following the Spanish invasion of Panama. Travel is often conducted with pirogues. On the Panamanian side, La Palma, the area's cultural center, is the capital of the province. Other population centers include Yaviza and El Real. The Darién Gap had a reported population of 8,000 in 1995 among five tribes. Maize, cassava, plantains, and bananas are staple crops on local farms.

There is no road, not even a primitive one, across the Darién. One can bypass it by boat, and for some years there was an underused ferry service. The remaining option is to hike from Colombia to Panama by trail, which is possible but very strenuous and dangerous. Heavy rain and flash floods are frequent, law enforcement and medical support are non-existent, rapes and robberies are common, and a broken leg can be fatal, as there is no way to reach assistance. However, this route was taken by hundreds of thousands of migrants since the 2010s, primarily Haitians and Venezuelans, to reach the Mexico–United States border. By 2021, the number was more than 130,000. In 2022, there were 250,000, and by 2023, 360,000 had crossed the Gap.

🔗 Russia 🔗 Russia/mass media in Russia 🔗 Radio Stations

The Pip is the nickname given by radio listeners to a shortwave radio station that broadcasts on the frequency 5448 kHz by day, and 3756 kHz during the night. It broadcasts short, repeated beeps at a rate of around 50 per minute, for 24 hours per day. The beep signal is occasionally interrupted by voice messages in Russian. The Pip has been active since around 1985, when its distinctive beeping sound was first recorded by listeners.

The station is commonly referred to as "The Pip" among English-speaking radio listeners. In Russia, it is known as Капля (Kaplya) "the drop". While its official name or callsign is not known, some of the voice transmissions begin with the code 8S1Shch (Cyrillic: 8С1Щ), which is generally considered to be the name of the station. However, this code may not be a callsign, but instead serve some other purpose. Radioscanner.ru identifies the owner of this station as a North-Caucasian military district communication center with callsign "Akacia" (ex-72nd communication center, Russian "72 узел связи штаба СКВО").

🔗 Computing 🔗 New Zealand

The Aamber Pegasus is a home computer first produced in New Zealand in 1981 by Technosys Research Labs.

The hardware was designed by Stewart J Holmes. The software was designed by Paul Gillingwater, Nigel Keam and Paul Carter.

It is thought that Apple Computers introduction of the Apple II computer into the New Zealand market, and its subsequent heavy educational discounting was the final nail in the coffin for Technosys and the Aamber Pegasus computer. Total production numbers are unknown, but it is thought "around one hundred" were sold.

🔗 Lists 🔗 Philosophy 🔗 Skepticism 🔗 Philosophy/Logic

In reasoning to argue a claim, a fallacy is reasoning that is evaluated as logically incorrect and that undermines the logical validity of the argument and permits its recognition as unsound. Regardless of their soundness, all registers and manners of speech can demonstrate fallacies.

Because of their variety of structure and application, fallacies are challenging to classify so as to satisfy all practitioners. Fallacies can be classified strictly by either their structure or content, such as classifying them as formal fallacies or informal fallacies, respectively. The classification of informal fallacies may be subdivided into categories such as linguistic, relevance through omission, relevance through intrusion, and relevance through presumption. On the other hand, fallacies may be classified by the process by which they occur, such as material fallacies (content), verbal fallacies (linguistic), and again formal fallacies (error in inference). In turn, material fallacies may be placed into the more general category of informal fallacies, while formal fallacies may be clearly placed into the more precise category of logical (deductive) fallacies. Yet, verbal fallacies may be placed into either informal or deductive classifications; compare equivocation which is a word or phrase based ambiguity (e.g., "he is mad", which may refer to either him being angry or clinically insane) to the fallacy of composition which is premise and inference based ambiguity (e.g., "this must be a good basketball team because each of its members is an outstanding player").

The conscious or habitual use of fallacies as rhetorical devices is prevalent in the desire to persuade when the focus is more on communication and eliciting common agreement rather than on the correctness of the reasoning. The effective use of a fallacy by an orator may be considered clever, but by the same token, the reasoning of that orator should be recognized as unsound, and thus the orator's claim, supported by an unsound argument, will be regarded as unfounded and dismissed.

🔗 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.

🔗 Arab world

The elephant clock was a medieval invention by Al-Jazari (1136–1206), an Arab engineer and inventor of various clocks. The device consisted of a weight powered water clock in the form of an Asian elephant. This horological technology was derived from earlier Indian clocks and Chinese clocks.

In China clock escapement mechanism was invented by the polymath and Buddhist monk Yi Xing as well as the hydraulic powered waterwheel and water clock in the mechanically-driven and rotated equatorial armillary sphere of the polymaths Zhang Heng and Ma Jun. The Elephant clock had some design differences compared to earlier Indian and Chinese clocks and the various elements of the clock are in the housing (howdah) on top of the elephant.

Al-Jazari upon finishing the development and construction of his Elephant clock wrote: "The elephant represents the Indian and African cultures, the two dragons represents Chinese culture, the phoenix represents Persian culture, the water work represents Greek culture, and the turban represents Islamic culture" signifying the multicultural mentality of the intellectual Al-Jazari.

In addition to its mechanical innovations, the clock itself is seen as an early example of multiculturalism represented in technology.

🔗 California 🔗 Companies 🔗 California/San Francisco Bay Area 🔗 Apple Inc. 🔗 Computing 🔗 Computing/Software 🔗 Media 🔗 Music theory

Napster was a peer-to-peer (P2P) file sharing application primarily associated with digital audio file distribution. Founded by Shawn Fanning and Sean Parker, the platform originally launched on June 1, 1999. Audio shared on the service was typically encoded in the MP3 format. As the software became popular, the company encountered legal difficulties over copyright infringement. Napster ceased operations in 2001 after losing multiple lawsuits and filed for bankruptcy in June 2002.

The P2P model employed by Napster involved a centralized database that indexed a complete list of all songs being shared from connected clients. While effective, the service could not function without the central database, which was hosted by Napster and eventually forced to shutdown. Following Napster's demise, alternative decentralized methods of P2P file-sharing emerged, including Gnutella, Freenet, FastTrack, and BitTorrent.

Napster's assets were eventually acquired by Roxio, and it re-emerged as an online music store commonly known as Napster 2.0. Best Buy later purchased the service and merged it with its Rhapsody streaming service on December 1, 2011. In 2016, the original branding was restored when Rhapsody was renamed Napster.

🔗 California 🔗 Energy 🔗 California/Southern California

The Santa Susana Field Laboratory is a complex of industrial research and development facilities located on a 2,668-acre (1,080 ha) portion of the Southern California Simi Hills in Simi Valley, California. It was used mainly for the development and testing of liquid-propellant rocket engines for the United States space program from 1949 to 2006, nuclear reactors from 1953 to 1980 and the operation of a U.S. government-sponsored liquid metals research center from 1966 to 1998. The site is located approximately 7 miles (11 km) northwest from the community of Canoga Park and approximately 30 miles (48 km) northwest of Downtown Los Angeles. Sage Ranch Park is adjacent on part of the northern boundary and the community of Bell Canyon along the entire southern boundary.

Throughout the years, about ten low-power nuclear reactors operated at SSFL, in addition to several "critical facilities" that helped develop nuclear science and applications. At least four of the ten nuclear reactors had accidents during their operation. The reactors located on the grounds of SSFL were considered experimental, and therefore, had no containment structures.

The site ceased research and development operations in 2006. The years of rocket testing, nuclear reactor testing, and liquid metal research have left the site "significantly contaminated". Environmental cleanup is ongoing.

The public who live near the site have over the years strongly urged a thorough cleanup of the site, citing cases of long term illnesses, including cancer cases at rates they claim are higher than normal. On March 30, 2018, a 7-year-old girl living in Simi Valley died of neuroblastoma, prompting public urging to thoroughly clean up the site; despite the fact that there is insufficient evidence to identify an explicit link between cancer rates and radioactive contamination in the area.

🔗 Sociology

The circulation of elites is a theory of regime change described by Italian sociologist Vilfredo Pareto (1848–1923).

Changes of regime, revolutions, and so on occur not when rulers are overthrown from below, but when one elite replaces another. The role of ordinary people in such transformation is not that of initiators or principal actors, but as followers and supporters of one elite or another.

🔗 United States/U.S. Government 🔗 United States 🔗 Biography 🔗 International relations 🔗 Human rights 🔗 Mass surveillance 🔗 Espionage 🔗 United States/North Carolina

Edward Joseph Snowden (born June 21, 1983) is an American whistleblower who copied and leaked highly classified information from the National Security Agency (NSA) in 2013 when he was a Central Intelligence Agency (CIA) employee and subcontractor. His disclosures revealed numerous global surveillance programs, many run by the NSA and the Five Eyes Intelligence Alliance with the cooperation of telecommunication companies and European governments, and prompted a cultural discussion about national security and individual privacy.

In 2013, Snowden was hired by an NSA contractor, Booz Allen Hamilton, after previous employment with Dell and the CIA. Snowden says he gradually became disillusioned with the programs with which he was involved and that he tried to raise his ethical concerns through internal channels but was ignored. On May 20, 2013, Snowden flew to Hong Kong after leaving his job at an NSA facility in Hawaii, and in early June he revealed thousands of classified NSA documents to journalists Glenn Greenwald, Laura Poitras, and Ewen MacAskill. Snowden came to international attention after stories based on the material appeared in The Guardian and The Washington Post. Further disclosures were made by other publications including Der Spiegel and The New York Times.

On June 21, 2013, the United States Department of Justice unsealed charges against Snowden of two counts of violating the Espionage Act of 1917 and theft of government property, following which the Department of State revoked his passport. Two days later, he flew into Moscow's Sheremetyevo Airport, where Russian authorities noted that his U.S. passport had been cancelled, and he was restricted to the airport terminal for over one month. Russia later granted Snowden the right of asylum with an initial visa for residence for one year, and repeated extensions have permitted him to stay at least until 2020. In early 2016, he became the president of the Freedom of the Press Foundation, a San Francisco-based organization that states its purpose is to protect journalists from hacking and government surveillance.

On September 17, 2019, his memoir Permanent Record was published. On the first day of publication, the U.S. Department of Justice filed a civil lawsuit against Snowden over publication of his memoir, alleging he had breached nondisclosure agreements signed with the U.S. federal government. Former The Guardian national security reporter Ewen MacAskill called the civil lawsuit a "huge mistake", noting that the "UK ban of Spycatcher 30 years ago created huge demand". The memoir was listed as no. 1 on Amazon's bestseller list that same day. In an interview with Amy Goodman on Democracy Now! on September 26, 2019, Snowden clarified he considers himself a "whistleblower" as opposed to a "leaker" as he considers "a leaker only distributes information for personal gain".