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🔗 United States 🔗 Environment 🔗 Medicine 🔗 United States/Louisiana

Cancer Alley (French: Allée du Cancer) is the regional nickname given to an 85-mile (137 km) stretch of land along the Mississippi River between Baton Rouge and New Orleans, in the River Parishes of Louisiana, which contains over 200 petrochemical plants and refineries. This area accounts for 25% of the petrochemical production in the United States. Environmentalists consider the region a sacrifice zone where rates of cancer caused by air pollution exceed the federal government's own limits of acceptable risk. Others have referred to the same region as "Death Alley".

Community leaders such as Sharon Lavigne have led the charge in protesting the expansion of the petrochemical industry in Cancer Alley, as well as addressing the associated racial and economic disparities.

🔗 Mathematics

The hairy ball theorem of algebraic topology (sometimes called the hedgehog theorem in Europe) states that there is no nonvanishing continuous tangent vector field on even-dimensional n-spheres. For the ordinary sphere, or 2‑sphere, if f is a continuous function that assigns a vector in R³ to every point p on a sphere such that f(p) is always tangent to the sphere at p, then there is at least one p such that f(p) = 0. The theorem was first stated by Henri Poincaré in the late 19th century, and first proven in 1912 by Luitzen Egbertus Jan Brouwer.

The theorem has been expressed colloquially as "you can't comb a hairy ball flat without creating a cowlick" or "you can't comb the hair on a coconut".

🔗 California 🔗 California/San Francisco Bay Area 🔗 Computing 🔗 Stanford University/SRI International 🔗 Stanford University

"The Mother of All Demos" is a name retroactively applied to a landmark computer demonstration, given at the Association for Computing Machinery / Institute of Electrical and Electronics Engineers (ACM/IEEE)—Computer Society's Fall Joint Computer Conference in San Francisco, which was presented by Douglas Engelbart on December 9, 1968.

The live demonstration featured the introduction of a complete computer hardware and software system called the oN-Line System or, more commonly, NLS. The 90-minute presentation essentially demonstrated almost all the fundamental elements of modern personal computing: windows, hypertext, graphics, efficient navigation and command input, video conferencing, the computer mouse, word processing, dynamic file linking, revision control, and a collaborative real-time editor (collaborative work). Engelbart's presentation was the first to publicly demonstrate all of these elements in a single system. The demonstration was highly influential and spawned similar projects at Xerox PARC in the early 1970s. The underlying technologies influenced both the Apple Macintosh and Microsoft Windows graphical user interface operating systems in the 1980s and 1990s.

🔗 United States 🔗 Linguistics 🔗 Linguistics/Applied Linguistics 🔗 Education

A 2019 report by the National Center for Education Statistics determined that mid to high literacy in the United States is 79% with 21% of American adults categorized as having "low level English literacy," including 4.1% classified as "functionally illiterate" and an additional 4% that could not participate. According to the U.S. Department of Education, 54% of adults in the United States have prose literacy below the 6th-grade level.

In many nations, the ability to read a simple sentence suffices as literacy, and was the previous standard for the U.S. The definition of literacy has changed greatly; the term is presently defined as the ability to use printed and written information to function in society, to achieve one's goals, and to develop one's knowledge and potential.

The United States Department of Education assesses literacy in the general population through its National Assessment of Adult Literacy (NAAL). The NAAL survey defines three types of literacy:

• prose literacy: the knowledge and skills needed to search, comprehend, and use continuous texts. Examples include editorials, news stories, brochures, and instructional materials.
• document literacy: the knowledge and skills needed to search, comprehend, and use non-continuous texts in various formats. Examples include job applications, payroll forms, transportation schedules, maps, tables, and drug and food labels.
• quantitative literacy: the knowledge and skills required to identify and perform computations, either alone or sequentially, using numbers embedded in printed materials. Examples include balancing a checkbook, figuring out tips, completing an order form, or determining an amount.

Modern jobs often demand a high level of literacy, and its lack in adults and adolescents has been studied extensively.

According to a 1992 survey, about 40 million adults had Level 1 literary competency, the lowest level, comprising understanding only basic written instructions. A number of reports and studies are published annually to monitor the nation's status, and initiatives to improve literacy rates are funded by government and external sources.

🔗 Russia 🔗 Russia/demographics and ethnography of Russia 🔗 Ukraine 🔗 Visual arts 🔗 Russia/history of Russia 🔗 Russia/visual arts in Russia

Reply of the Zaporozhian Cossacks to Sultan Mehmed IV of the Ottoman Empire, also known as Cossacks of Saporog Are Drafting a Manifesto (Russian: Запорожцы пишут письмо турецкому султану), is a painting by Russian artist Ilya Repin. The 2.03 m (6 foot 7 inch) by 3.58 m (11 foot 9 inch) canvas was started in 1880 and finished in 1891. Repin recorded the years of work along the lower edge of the canvas. Alexander III bought the painting for 35,000 rubles, at the time the greatest sum ever paid for a Russian painting. Since then, the canvas has been exhibited in the State Russian Museum in Saint Petersburg.

🔗 Cryptography 🔗 Cryptography/Computer science

PGPfone was a secure voice telephony system developed by Philip Zimmermann in 1995. The PGPfone protocol had little in common with Zimmermann's popular PGP email encryption package, except for the use of the name. It used ephemeral Diffie-Hellman protocol to establish a session key, which was then used to encrypt the stream of voice packets. The two parties compared a short authentication string to detect a Man-in-the-middle attack, which is the most common method of wiretapping secure phones of this type. PGPfone could be used point-to-point (with two modems) over the public switched telephone network, or over the Internet as an early Voice over IP system.

In 1996, there were no protocol standards for Voice over IP. Ten years later, Zimmermann released the successor to PGPfone, Zfone and ZRTP, a newer and secure VoIP protocol based on modern VoIP standards. Zfone builds on the ideas of PGPfone.

According to the MIT PGPfone web page, "MIT is no longer distributing PGPfone. Given that the software has not been maintained since 1997, we doubt it would run on most modern systems."

🔗 Computing

Unlambda is a minimal, "nearly pure" functional programming language invented by David Madore. It is based on combinatory logic, an expression system without the lambda operator or free variables. It relies mainly on two built-in functions (s and k) and an apply operator (written `, the backquote character). These alone make it Turing-complete, but there are also some input/output (I/O) functions to enable interacting with the user, some shortcut functions, and a lazy evaluation function. Variables are unsupported.

Unlambda is free and open-source software distributed under a GNU General Public License (GPL) 2.0 or later.

🔗 Spaceflight 🔗 Physics 🔗 Physics/relativity

Gravity Probe B (GP-B) was a satellite-based experiment to test two unverified predictions of general relativity: the geodetic effect and frame-dragging. This was to be accomplished by measuring, very precisely, tiny changes in the direction of spin of four gyroscopes contained in an Earth-orbiting satellite at 650 km (400 mi) altitude, crossing directly over the poles.

The satellite was launched on 20 April 2004 on a Delta II rocket. The spaceflight phase lasted until 2005; Its aim was to measure spacetime curvature near Earth, and thereby the stress–energy tensor (which is related to the distribution and the motion of matter in space) in and near Earth. This provided a test of general relativity, gravitomagnetism and related models. The principal investigator was Francis Everitt.

Initial results confirmed the expected geodetic effect to an accuracy of about 1%. The expected frame-dragging effect was similar in magnitude to the current noise level (the noise being dominated by initially unmodeled effects due to nonuniform coatings on the gyroscopes). Work continued to model and account for these sources of error, thus permitting extraction of the frame-dragging signal. By August 2008, the frame-dragging effect had been confirmed to within 15% of the expected result, and the December 2008 NASA report indicated that the geodetic effect was confirmed to be better than 0.5%.

In an article published in the journal Physical Review Letters in 2011, the authors reported analysis of the data from all four gyroscopes results in a geodetic drift rate of −6601.8±18.3 mas/yr and a frame-dragging drift rate of −37.2±7.2 mas/yr, in good agreement with the general relativity predictions of −6606.1±0.28% mas/yr and −39.2±0.19% mas/yr, respectively.

🔗 Computing 🔗 Computer science 🔗 Cryptography 🔗 Cryptography/Computer science

Diffie–Hellman key exchange is a method of securely exchanging cryptographic keys over a public channel and was one of the first public-key protocols as conceived by Ralph Merkle and named after Whitfield Diffie and Martin Hellman. DH is one of the earliest practical examples of public key exchange implemented within the field of cryptography.

Traditionally, secure encrypted communication between two parties required that they first exchange keys by some secure physical means, such as paper key lists transported by a trusted courier. The Diffie–Hellman key exchange method allows two parties that have no prior knowledge of each other to jointly establish a shared secret key over an insecure channel. This key can then be used to encrypt subsequent communications using a symmetric key cipher.

Diffie–Hellman is used to secure a variety of Internet services. However, research published in October 2015 suggests that the parameters in use for many DH Internet applications at that time are not strong enough to prevent compromise by very well-funded attackers, such as the security services of large governments.

The scheme was published by Whitfield Diffie and Martin Hellman in 1976, but in 1997 it was revealed that James H. Ellis, Clifford Cocks, and Malcolm J. Williamson of GCHQ, the British signals intelligence agency, had previously shown in 1969 how public-key cryptography could be achieved.

Although Diffie–Hellman key agreement itself is a non-authenticated key-agreement protocol, it provides the basis for a variety of authenticated protocols, and is used to provide forward secrecy in Transport Layer Security's ephemeral modes (referred to as EDH or DHE depending on the cipher suite).

The method was followed shortly afterwards by RSA, an implementation of public-key cryptography using asymmetric algorithms.

Expired U.S. Patent 4,200,770 from 1977 describes the now public-domain algorithm. It credits Hellman, Diffie, and Merkle as inventors.

🔗 Medicine 🔗 Skepticism 🔗 Anthropology 🔗 Medicine/Psychiatry

In medicine and medical anthropology, a culture-bound syndrome, culture-specific syndrome, or folk illness is a combination of psychiatric and somatic symptoms that are considered to be a recognizable disease only within a specific society or culture. There are no objective biochemical or structural alterations of body organs or functions, and the disease is not recognized in other cultures. The term culture-bound syndrome was included in the fourth version of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1994) which also includes a list of the most common culture-bound conditions (DSM-IV: Appendix I). Counterpart within the framework of ICD-10 (Chapter V) are the culture-specific disorders defined in Annex 2 of the Diagnostic criteria for research.

More broadly, an endemic that can be attributed to certain behavior patterns within a specific culture by suggestion may be referred to as a potential behavioral epidemic. As in the cases of drug use, or alcohol and smoking abuses, transmission can be determined by communal reinforcement and person-to-person interactions. On etiological grounds, it can be difficult to distinguish the causal contribution of culture upon disease from other environmental factors such as toxicity.