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🔗 United States 🔗 Library of Congress 🔗 Geography 🔗 Maps 🔗 Libraries

The Waldseemüller map or Universalis Cosmographia ("Universal Cosmography") is a printed wall map of the world by German cartographer Martin Waldseemüller, originally published in April 1507. It is known as the first map to use the name "America". The name America is placed on what is now called South America on the main map. As explained in Cosmographiae Introductio, the name was bestowed in honor of the Italian Amerigo Vespucci.

The map is drafted on a modification of Ptolemy's second projection, expanded to accommodate the Americas and the high latitudes. A single copy of the map survives, presently housed at the Library of Congress in Washington, D.C.

Waldseemüller also created globe gores, printed maps designed to be cut out and pasted onto spheres to form globes of the Earth. The wall map, and his globe gores of the same date, depict the American continents in two pieces. These depictions differ from the small inset map in the top border of the wall map, which shows the two American continents joined by an isthmus.

🔗 Africa 🔗 Philosophy 🔗 Philosophy/Anarchism 🔗 Somalia

Xeer (pronounced [ħeːr]) is the traditional legal system of Somalia, and one of the three systems from which formal Somali law draws its inspiration, the others being civil law and Islamic law. It is believed to pre-date Islam, although it was influenced by Islam and retains many of the faith's conservative elements. Under this system, elders, known as the xeer begti serve as mediator judges and help settle court cases, taking precedent and custom into account. Xeer is polycentric in that different groups within Somali society have different interpretations of xeer.

🔗 Computer science

In computer science, corecursion is a type of operation that is dual to recursion. Whereas recursion works analytically, starting on data further from a base case and breaking it down into smaller data and repeating until one reaches a base case, corecursion works synthetically, starting from a base case and building it up, iteratively producing data further removed from a base case. Put simply, corecursive algorithms use the data that they themselves produce, bit by bit, as they become available, and needed, to produce further bits of data. A similar but distinct concept is generative recursion which may lack a definite "direction" inherent in corecursion and recursion.

Where recursion allows programs to operate on arbitrarily complex data, so long as they can be reduced to simple data (base cases), corecursion allows programs to produce arbitrarily complex and potentially infinite data structures, such as streams, so long as it can be produced from simple data (base cases) in a sequence of finite steps. Where recursion may not terminate, never reaching a base state, corecursion starts from a base state, and thus produces subsequent steps deterministically, though it may proceed indefinitely (and thus not terminate under strict evaluation), or it may consume more than it produces and thus become non-productive. Many functions that are traditionally analyzed as recursive can alternatively, and arguably more naturally, be interpreted as corecursive functions that are terminated at a given stage, for example recurrence relations such as the factorial.

Corecursion can produce both finite and infinite data structures as results, and may employ self-referential data structures. Corecursion is often used in conjunction with lazy evaluation, to produce only a finite subset of a potentially infinite structure (rather than trying to produce an entire infinite structure at once). Corecursion is a particularly important concept in functional programming, where corecursion and codata allow total languages to work with infinite data structures.

🔗 History of Science

A knowledge production mode is a term from the sociology of science which refers to the way (scientific) knowledge is produced. So far, three modes have been conceptualized. Mode 1 production of knowledge is knowledge production motivated by scientific knowledge alone (basic research) which is not primarily concerned by the applicability of its findings. Mode 1 is founded on a conceptualization of science as separated into discrete disciplines (e.g., a biologist does not bother about chemistry). Mode 2 was coined in 1994 in juxtaposition to Mode 1 by Michael Gibbons, Camille Limoges, Helga Nowotny, Simon Schwartzman, Peter Scott and Martin Trow. In Mode 2, multidisciplinary teams are brought together for short periods of time to work on specific problems in the real world for knowledge production (applied research) in the knowledge society. Mode 2 can be explained by the way research funds are distributed among scientists and how scientists focus on obtaining these funds in terms of five basic features: 1) knowledge produced in the context of application; (2) transdisciplinarity; (3) heterogeneity and organizational diversity; (4) social accountability and reflexivity; (5) and quality control. Subsequently, Carayannis and Campbell described a Mode 3 knowledge in 2006.

🔗 Computing

Technical debt (also known as design debt or code debt, but can be also related to other technical endeavors) is a concept in software development that reflects the implied cost of additional rework caused by choosing an easy (limited) solution now instead of using a better approach that would take longer.

As with monetary debt, if technical debt is not repaid, it can accumulate 'interest', making it harder to implement changes. Unaddressed technical debt increases software entropy. Technical debt is not necessarily a bad thing, and sometimes (e.g., as a proof-of-concept) is required to move projects forward. On the other hand, some experts claim that the "technical debt" metaphor tends to minimize the impact, which results in insufficient prioritization of the necessary work to correct it.

As a change is started on a codebase, there is often the need to make other coordinated changes in other parts of the codebase or documentation. Changes required that are not completed are considered debt, and until paid, will incur interest on top of interest, making it cumbersome to build a project. Although the term is used in software development primarily, it can also be applied to other professions.

🔗 Books 🔗 Comics 🔗 Comics/DC Comics

Understanding Comics: The Invisible Art is a 1993 non-fiction work of comics by American cartoonist Scott McCloud. It explores formal aspects of comics, the historical development of the medium, its fundamental vocabulary, and various ways in which these elements have been used. It expounds theoretical ideas about comics as an art form and medium of communication, and is itself written in comic book form.

Understanding Comics received praise from notable comic and graphic novel authors such as Art Spiegelman, Will Eisner, Alan Moore, Neil Gaiman, and Garry Trudeau (who reviewed the book for the New York Times). Although the book has prompted debate over many of McCloud’s conclusions, its discussions of "iconic" art and the concept of "closure" between panels have become common reference points in discussions of the medium.

The title of Understanding Comics is an homage to Marshall McLuhan's seminal 1964 work Understanding Media.

🔗 Mathematics 🔗 Statistics

In statistical hypothesis testing, a type I error is the rejection of a true null hypothesis (also known as a "false positive" finding or conclusion), while a type II error is the non-rejection of a false null hypothesis (also known as a "false negative" finding or conclusion). Much of statistical theory revolves around the minimization of one or both of these errors, though the complete elimination of either is a statistical impossibility for non-deterministic algorithms. By selecting a low threshold (cut-off) value and modifying the alpha (p) level, the quality of the hypothesis test can be increased. The knowledge of Type I errors and Type II errors is widely used in medical science, biometrics and computer science.

🔗 Computing 🔗 Business 🔗 Computing/Software

The bus factor is a measurement of the risk resulting from information and capabilities not being shared among team members, derived from the phrase "in case they get hit by a bus." It is also known as the bread truck scenario, lottery factor, truck factor, bus/truck number, or lorry factor.

The concept is similar to the much older idea of key person risk, but considers the consequences of losing key technical experts, versus financial or managerial executives (who are theoretically replaceable at an insurable cost). Personnel must be both key and irreplaceable to contribute to the bus factor; losing a replaceable or non-key person would not result in a bus-factor effect.

The term was first applied to software development, where a team member might create critical components by crafting code that performs well, but which also is unavailable to other team members, such as work that was undocumented, never shared, encrypted, obfuscated, unpublished, or otherwise incomprehensible to others. Thus a key component would be effectively lost as a direct consequence of the absence of that team member, making the member key. If this component was key to the project's advancement, the project would stall.

🔗 Medicine 🔗 Pharmacology

Sofosbuvir, sold under the brand name Sovaldi among others, is a medication used to treat hepatitis C. It is only recommended with some combination of ribavirin, peginterferon-alfa, simeprevir, ledipasvir, daclatasvir, or velpatasvir. Cure rates are 30 to 97% depending on the type of hepatitis C virus involved. Safety during pregnancy is unclear; some of the medications used in combination may result in harm to the baby. It is taken by mouth.

Common side effects include feeling tired, headache, nausea, and trouble sleeping. Side effects are generally more common in interferon-containing regimens. Sofosbuvir may reactivate hepatitis B in those who have been previously infected. In combination with ledipasvir, daclatasvir or simeprevir it is not recommended with amiodarone due to the risk of an abnormally slow heartbeat. Sofosbuvir is in the nucleotide analog family of medication and works by blocking the hepatitis C NS5B protein.

Sofosbuvir was discovered in 2007, and approved for medical use in the United States in 2013. It is on the World Health Organization's List of Essential Medicines, the safest and most effective medicines needed in a health system. As of 2016, a 12-week course of treatment costs about US$84,000 in the United States, US$53,000 in the United Kingdom, US$45,000 in Canada, and about US$500 in India. Over 60,000 people were treated with sofosbuvir in its first 30 weeks being sold in the United States.

🔗 China/Chinese history 🔗 China 🔗 Civil engineering 🔗 Archaeology 🔗 Museums 🔗 World Heritage Sites

The Dujiangyan (Chinese: 都江堰; pinyin: Dūjiāngyàn) is an ancient irrigation system in Dujiangyan City, Sichuan, China. Originally constructed around 256 BC by the State of Qin as an irrigation and flood control project, it is still in use today. The system's infrastructure develops on the Min River (Minjiang), the longest tributary of the Yangtze. The area is in the west part of the Chengdu Plain, between the Sichuan basin and the Tibetan plateau. Originally, the Min would rush down from the Min Mountains and slow down abruptly after reaching the Chengdu Plain, filling the watercourse with silt, thus making the nearby areas extremely prone to floods. Li Bing, then governor of Shu for the state of Qin, and his son headed the construction of the Dujiangyan, which harnessed the river using a new method of channeling and dividing the water rather than simply damming it. The water management scheme is still in use today to irrigate over 5,300 square kilometres (2,000 sq mi) of land in the region. The Dujiangyan, the Zhengguo Canal in Shaanxi and the Lingqu Canal in Guangxi are collectively known as the "three great hydraulic engineering projects of the Qin."