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🔗 Aviation 🔗 Aviation/aircraft 🔗 Florida

The Wingless Electromagnetic Air Vehicle (WEAV) is a heavier than air flight system developed at the University of Florida, funded by the Air Force Office of Scientific Research. The WEAV was invented in 2006 by Dr. Subrata Roy, plasma physicist, aerospace engineering professor at the University of Florida, and has been a subject of several patents. The WEAV employs no moving parts, and combines the aircraft structure, propulsion, energy production and storage, and control subsystems into one integrated system.

🔗 Cryptography 🔗 Cryptography/Computer science

Shamir's Secret Sharing is an algorithm in cryptography created by Adi Shamir. It is a form of secret sharing, where a secret is divided into parts, giving each participant its own unique part.

To reconstruct the original secret, a minimum number of parts is required. In the threshold scheme this number is less than the total number of parts. Otherwise all participants are needed to reconstruct the original secret.

🔗 Physics

Wigner's friend is a thought experiment in theoretical quantum physics, first conceived by the physicist Eugene Wigner in 1961., and developed into a thought experiment by David Deutsch in 1985. The scenario involves an indirect observation of a quantum measurement: An observer W observes another observer F who performs a quantum measurement on a physical system. The two observers then formulate a statement about the physical system's state after the measurement according to the laws of quantum theory. However, in most of the interpretations of quantum theory, the resulting statements of the two observers contradict each other. This reflects a seeming incompatibility of two laws in quantum theory: the deterministic and continuous time evolution of the state of a closed system and the probabilistic, discontinuous collapse of the state of a system upon measurement. Wigner's friend is therefore directly linked to the measurement problem in quantum mechanics with its famous Schrödinger's cat paradox.

🔗 Environment 🔗 Economics 🔗 Philosophy 🔗 Politics 🔗 Philosophy/Ethics 🔗 Game theory 🔗 Fisheries and Fishing

In economic science, the tragedy of the commons is a situation in which individual users, who have open access to a resource unhampered by shared social structures or formal rules that govern access and use, act independently according to their own self-interest and, contrary to the common good of all users, cause depletion of the resource through their uncoordinated action. The concept originated in an essay written in 1833 by the British economist William Forster Lloyd, who used a hypothetical example of the effects of unregulated grazing on common land (also known as a "common") in Great Britain and Ireland. The concept became widely known as the "tragedy of the commons" over a century later after an article written by Garrett Hardin in 1968. Faced with evidence of historical and existing commons, Hardin later retracted his original thesis, stating that the title should have been "The Tragedy of the Unmanaged Commons".

Although taken as a hypothetical example by Lloyd, the historical demise of the commons of Britain and Europe resulted not from misuse of long-held rights of usage by the commoners, but from the commons' owners enclosing and appropriating the land, abrogating the commoners' rights.

Although open-access resource systems may collapse due to overuse (such as in overfishing), many examples have existed and still do exist where members of a community with regulated access to a common resource co-operate to exploit those resources prudently without collapse, or even creating "perfect order". Elinor Ostrom was awarded the 2009 Nobel Memorial Prize in Economic Sciences for demonstrating this concept in her book Governing the Commons, which included examples of how local communities were able to do this without top-down regulations or privatization. On the other hand, Dieter Helm argues that these examples are context-specific and the tragedy of the commons "is not generally solved this way. If it were, the destruction of nature would not have occurred."

In a modern economic context, "commons" is taken to mean any open-access and unregulated resource such as the atmosphere, oceans, rivers, ocean fish stocks, or even an office refrigerator. In a legal context, it is a type of property that is neither private nor public, but rather held jointly by the members of a community, who govern access and use through social structures, traditions, or formal rules.

In environmental science, the "tragedy of the commons" is often cited in connection with sustainable development, meshing economic growth and environmental protection, as well as in the debate over global warming. It has also been used in analyzing behavior in the fields of economics, evolutionary psychology, anthropology, game theory, politics, taxation, and sociology.

🔗 Politics

In political jargon, a self-licking ice cream cone is a self-perpetuating system that has no purpose other than to sustain itself. The phrase appeared to have been first used in 1992, in On Self-Licking Ice Cream Cones, a paper by Pete Worden about NASA's bureaucracy. James A. Vedda described it as "Why do humans go into space? So we can go farther into space!"

Since then, the term has been used to describe the habit of government funded organisations and programs spending taxpayer money to lobby for more funding from the taxpayer. Other things compared have included financial bubbles, chatshows and reality television. In The Irish Times, Kevin Courtney observed that "many organisations are also stuck in limbo, destined to keep lurching on without ever achieving their stated goal. That’s because their real goal is simply to carry on regardless." The Cold War infrastructure has also been compared to a self-licking ice cream cone, given that expensive projects continued to be financed long after world communism had ceased to pose a viable threat.

Richard Hoggart used the term to describe certain United Nations programmes.

In sport, the Bowl Alliance was criticised using the term.

🔗 Medicine 🔗 Medicine/Ophthalmology

The Purkinje effect or Purkinje phenomenon (Czech: [ˈpurkɪɲɛ] (listen); sometimes called the Purkinje shift, often incorrectly pronounced ) is the tendency for the peak luminance sensitivity of the eye to shift toward the blue end of the color spectrum at low illumination levels as part of dark adaptation. In consequence, reds will appear darker relative to other colors as light levels decrease. The effect is named after the Czech anatomist Jan Evangelista Purkyně. While the effect is often described from the perspective of the human eye, it is well established in a number of animals under the same name to describe the general shifting of spectral sensitivity due to pooling of rod and cone output signals as a part of dark/light adaptation.

This effect introduces a difference in color contrast under different levels of illumination. For instance, in bright sunlight, geranium flowers appear bright red against the dull green of their leaves, or adjacent blue flowers, but in the same scene viewed at dusk, the contrast is reversed, with the red petals appearing a dark red or black, and the leaves and blue petals appearing relatively bright.

The sensitivity to light in scotopic vision varies with wavelength, though the perception is essentially black-and-white. The Purkinje shift is the relation between the absorption maximum of rhodopsin, reaching a maximum at about 500 nanometres (2.0×10⁻⁵ in), and that of the opsins in the longer-wavelength cones that dominate in photopic vision, about 555 nanometres (2.19×10⁻⁵ in) (green).

In visual astronomy, the Purkinje shift can affect visual estimates of variable stars when using comparison stars of different colors, especially if one of the stars is red.

🔗 Biography 🔗 Literature 🔗 Women writers 🔗 Biography/arts and entertainment

Barbara Newhall Follett (March 4, 1914 – disappeared December 7, 1939) was an American child prodigy novelist. Her first novel, The House Without Windows, was published in January 1927, when she was twelve years old. Her next novel, The Voyage of the Norman D.w, received critical acclaim when she was fourteen.

In December 1939, aged 25, Follett reportedly became depressed with her marriage and walked out of her apartment, never to be seen again.

🔗 Medicine 🔗 Food and drink 🔗 Chemistry 🔗 Medicine/Toxicology

Olestra (also known by its brand name Olean) is a fat substitute that adds no calories to products. It has been used in the preparation of otherwise high-fat foods, thereby lowering or eliminating their fat content. The Food and Drug Administration (FDA) originally approved olestra for use in the US as a replacement for fats and oils in prepackaged ready-to-eat snacks in 1996, concluding that such use "meets the safety standard for food additives, reasonable certainty of no harm".^: 46399 In the late 2000s, olestra lost its popularity due to supposed side effects and has been largely phased out, but products containing the ingredient can still be purchased at grocery stores in some countries. As of 2023, no products are sold in the United States using Olestra.

🔗 Computing 🔗 Time 🔗 Linux

Unix time (also known as Epoch time, POSIX time, seconds since the Epoch, or UNIX Epoch time) is a system for describing a point in time. It is the number of seconds that have elapsed since the Unix epoch, that is the time 00:00:00 UTC on 1 January 1970, minus leap seconds. Leap seconds are ignored, with a leap second having the same Unix time as the second before it, and every day is treated as if it contains exactly 86400 seconds. Due to this treatment, Unix time is not a true representation of UTC.

Unix time is widely used in operating systems and file formats. In Unix-like operating systems, date is a command which will print or set the current time; by default, it prints or sets the time in the system time zone, but with the -u flag, it prints or sets the time in UTC and, with the TZ environment variable set to refer to a particular time zone, prints or sets the time in that time zone.

🔗 Mathematics 🔗 Economics 🔗 Statistics 🔗 Sociology 🔗 Globalization

In economics, the Gini coefficient ( JEE-nee), sometimes called the Gini index or Gini ratio, is a measure of statistical dispersion intended to represent the income or wealth distribution of a nation's residents, and is the most commonly used measurement of inequality. It was developed by the Italian statistician and sociologist Corrado Gini and published in his 1912 paper Variability and Mutability (Italian: Variabilità e mutabilità).

The Gini coefficient measures the inequality among values of a frequency distribution (for example, levels of income). A Gini coefficient of zero expresses perfect equality, where all values are the same (for example, where everyone has the same income). A Gini coefficient of one (or 100%) expresses maximal inequality among values (e.g., for a large number of people, where only one person has all the income or consumption, and all others have none, the Gini coefficient will be very nearly one). For larger groups, values close to one are very unlikely in practice. Given the normalization of both the cumulative population and the cumulative share of income used to calculate the Gini coefficient, the measure is not overly sensitive to the specifics of the income distribution, but rather only on how incomes vary relative to the other members of a population. The exception to this is in the redistribution of income resulting in a minimum income for all people. When the population is sorted, if their income distribution were to approximate a well-known function, then some representative values could be calculated.

The Gini coefficient was proposed by Gini as a measure of inequality of income or wealth. For OECD countries, in the late 20th century, considering the effect of taxes and transfer payments, the income Gini coefficient ranged between 0.24 and 0.49, with Slovenia being the lowest and Mexico the highest. African countries had the highest pre-tax Gini coefficients in 2008–2009, with South Africa the world's highest, variously estimated to be 0.63 to 0.7, although this figure drops to 0.52 after social assistance is taken into account, and drops again to 0.47 after taxation. The global income Gini coefficient in 2005 has been estimated to be between 0.61 and 0.68 by various sources.

There are some issues in interpreting a Gini coefficient. The same value may result from many different distribution curves. The demographic structure should be taken into account. Countries with an aging population, or with a baby boom, experience an increasing pre-tax Gini coefficient even if real income distribution for working adults remains constant. Scholars have devised over a dozen variants of the Gini coefficient.