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🔗 Economics

Baumol's cost disease (or the Baumol effect) is the rise of salaries in jobs that have experienced no or low increase of labor productivity, in response to rising salaries in other jobs that have experienced higher labor productivity growth. This pattern seemingly goes against the theory in classical economics in which real wage growth is closely tied to labor productivity changes. The phenomenon was described by William J. Baumol and William G. Bowen in the 1960s.

The rise of wages in jobs without productivity gains is from the requirement to compete for employees with jobs that have experienced gains and so can naturally pay higher salaries, just as classical economics predicts. For instance, if the retail sector pays its managers 19th-century-style salaries, the managers may decide to quit to get a job at an automobile factory, where salaries are higher because of high labor productivity. Thus, managers' salaries are increased not by labor productivity increases in the retail sector but by productivity and corresponding wage increases in other industries.

🔗 Books 🔗 Linguistics 🔗 Linguistics/Applied Linguistics 🔗 Translation studies

O novo guia da conversação em portuguez e inglez, commonly known by the name English as She Is Spoke, is a 19th-century book written by Pedro Carolino, with some editions crediting José da Fonseca as a co-author. It was intended as a Portuguese–English conversational guide or phrase book; however, as the "English" translations provided are usually inaccurate or incoherent, it is regarded as a classic source of unintentional humour in translation.

The humour is largely a result of Carolino's indiscriminate use of literal translation; this causes many idiomatic expressions to be translated ineptly. For example, Carolino translates the Portuguese phrase chover a cântaros as "raining in jars", when an analogous English idiom is available in the form of "raining buckets".

It is widely believed that Carolino could not speak English, and that a French–English dictionary was used to translate an earlier Portuguese–French phrase book, O novo guia da conversação em francês e português, written by José da Fonseca. Carolino likely added Fonseca's name to the book without his permission in an attempt to give it some credibility. The Portuguese–French phrase book is apparently a competent work, without the defects that characterize English as She Is Spoke.

The title English as She Is Spoke was given to the book in its 1883 republication; this phrase does not actually appear in the original phrasebook, nor does the word "spoke."

🔗 Computing 🔗 Computer science 🔗 Computing/Software

Unums (universal numbers) are a family of number formats and arithmetic for implementing real numbers on a computer, proposed by John L. Gustafson in 2015. They are designed as an alternative to the ubiquitous IEEE 754 floating-point standard. The latest version is known as posits.

🔗 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.

🔗 Time

The Symmetry454 calendar (Sym454) is a proposal for calendar reform created by Irv Bromberg of the University of Toronto, Canada. It is a perennial solar calendar that conserves the traditional month pattern and 7-day week, has symmetrical equal quarters in 82% of the years in its 293-year cycle, and starts every month on Monday.

🔗 Computing

FRACTRAN is a Turing-complete esoteric programming language invented by the mathematician John Conway. A FRACTRAN program is an ordered list of positive fractions together with an initial positive integer input n. The program is run by updating the integer n as follows:

1. for the first fraction f in the list for which nf is an integer, replace n by nf
2. repeat this rule until no fraction in the list produces an integer when multiplied by n, then halt.

Conway 1987 gives the following formula for primes in FRACTRAN:

${\displaystyle \left({\frac {17}{91}},{\frac {78}{85}},{\frac {19}{51}},{\frac {23}{38}},{\frac {29}{33}},{\frac {77}{29}},{\frac {95}{23}},{\frac {77}{19}},{\frac {1}{17}},{\frac {11}{13}},{\frac {13}{11}},{\frac {15}{2}},{\frac {1}{7}},{\frac {55}{1}}\right)}$

Starting with n=2, this FRACTRAN program generates the following sequence of integers:

2, 15, 825, 725, 1925, 2275, 425, 390, 330, 290, 770, ... (sequence A007542 in the OEIS)

After 2, this sequence contains the following powers of 2:

${\displaystyle 2^{2}=4,\,2^{3}=8,\,2^{5}=32,\,2^{7}=128,\,2^{11}=2048,\,2^{13}=8192,\,2^{17}=131072,\,2^{19}=524288,\,\dots }$ (sequence A034785 in the OEIS)

which are the prime powers of 2.

🔗 United States/U.S. Government 🔗 United States 🔗 History 🔗 Computing 🔗 Cryptography 🔗 Cryptography/Computer science

In cryptography, the EFF DES cracker (nicknamed "Deep Crack") is a machine built by the Electronic Frontier Foundation (EFF) in 1998, to perform a brute force search of the Data Encryption Standard (DES) cipher's key space – that is, to decrypt an encrypted message by trying every possible key. The aim in doing this was to prove that the key size of DES was not sufficient to be secure.

🔗 Military history 🔗 Military history/North American military history 🔗 Military history/Canadian military history

The Royal Canadian Air Force Exercise Plans are two exercise plans developed for the Royal Canadian Air Force (RCAF) by Dr. Bill Orban in the late 1950s, first published in 1961. The 5BX plan (Five Basic Exercises) was developed for men; a corresponding program was developed for women under the name XBX (Ten Basic Exercises) and the two plans were subsequently published together as one book. The popularity of the programs in many countries around the world helped to launch modern fitness culture.

🔗 Disambiguation

A rat king is a rare phenomenon where a group of rats' tails become entangled.

Rat King or Ratking may also refer to:

🔗 Fishes

The sturddlefish is a hybrid of the American paddlefish (Polyodon spathula) and the Russian sturgeon (Acipenser gueldenstaedtii), accidentally created by researchers in 2019 and announced in 2020. Obtaining living hybrids through breeding individuals from different families is unusual, especially given that the two species' last common ancestor lived 184 million years ago. The hybrids were created accidentally during attempts to induce gynogenesis, a type of parthenogenic reproduction where a sperm cell must be present to trigger embryogenesis but does not genetically contribute to the offspring. Hundreds of hybrid fish were created, of which about two-thirds survived over one month, and about 100 survived for one year. As of July 2020, all living hybrid fish are living in captivity at the research lab in Hungary. There are no further plans to create new sturddlefish.