Random Articles (Page 3)
Have a deep view into what people are curious about.
π Clock on iOS6 iPads is an homage to a 1944 design by Hans Hilfiker
Discussed on
- "Clock on iOS6 iPads is an homage to a 1944 design by Hans Hilfiker" | 2012-09-20 | 27 Upvotes 20 Comments
π Hypothetical types of biochemistry
Hypothetical types of biochemistry are forms of biochemistry speculated to be scientifically viable but not proven to exist at this time. The kinds of living organisms currently known on Earth all use carbon compounds for basic structural and metabolic functions, water as a solvent, and DNA or RNA to define and control their form. If life exists on other planets or moons, it may be chemically similar; it is also possible that there are organisms with quite different chemistriesβfor instance, involving other classes of carbon compounds, compounds of another element, or another solvent in place of water.
The possibility of life-forms being based on "alternative" biochemistries is the topic of an ongoing scientific discussion, informed by what is known about extraterrestrial environments and about the chemical behaviour of various elements and compounds. It is of interest in synthetic biology and is also a common subject in science fiction.
The element silicon has been much discussed as a hypothetical alternative to carbon. Silicon is in the same group as carbon on the periodic table and, like carbon, it is tetravalent. Hypothetical alternatives to water include ammonia, which, like water, is a polar molecule, and cosmically abundant; and non-polar hydrocarbon solvents such as methane and ethane, which are known to exist in liquid form on the surface of Titan.
Discussed on
- "Hypothetical Types of Biochemistry" | 2020-05-21 | 49 Upvotes 7 Comments
- "Hypothetical types of biochemistry" | 2015-03-25 | 42 Upvotes 2 Comments
π Ryan Model 147
The Ryan Model 147 Lightning Bug is a jet-powered drone, or unmanned aerial vehicle, produced and developed by Ryan Aeronautical from the earlier Ryan Firebee target drone series.
Beginning in 1962, the Model 147 was introduced as a reconnaissance RPV (Remotely Piloted Vehicle, nomenclature of that era) for a United States Air Force project named Fire Fly. Over the next decade β assisted with secret funding from the recently formed National Reconnaissance Office along with support of the Strategic Air Command and Ryan Aeronautical's own resources β the basic Model 147 design would be developed into a diverse series of variants configured for a wide array of mission-specific roles, with multiple new systems, sensors and payloads used, modified and improved upon during the operational deployment of these drones in Southeast Asia. Missions performed by the Model 147 series RPVs included high- and low-altitude photographic and electronic aerial reconnaissance, surveillance, decoy, electronic warfare, signals intelligence, and psychological warfare.
The Ryan drones were designed without landing gear for simplicity and to save weight. Like its Firebee predecessor, the Model 147 could either be air-launched from a larger carrier aircraft or launched from the ground using a solid rocket booster; at completion of its mission the drone deployed its own recovery parachute which could be snatched in mid-air by a recovery helicopter (in a combat environment it was naturally not desired to recover the drone on, from or near enemy territory and ground or water impact could also cause damage to or loss of the drone or its payload).
At the end of the Vietnam War in 1975 the U.S. military's available funding and need for combat drones severely declined, even as Teledyne Ryan introduced further advanced developments of the Model 147 series such as the BGM-34 strike and defense suppression RPVs. Costs of maintaining the Lightning Bugs at full readiness could no longer be justified. Only by the 1990s did substantial interest, organization and funding again emerge from the U.S. Air Force and intelligence agencies to develop, acquire and widely deploy combat UAVs.
Discussed on
- "Ryan Model 147" | 2015-04-29 | 19 Upvotes 2 Comments
π Zoopharmacognosy
Zoopharmacognosy is a behaviour in which non-human animals apparently self-medicate by selecting and ingesting or topically applying plants, soils, insects, and psychoactive drugs to prevent or reduce the harmful effects of pathogens and toxins. The term derives from Greek roots zoo ("animal"), pharmacon ("drug, medicine"), and gnosy ("knowing").
An example of zoopharmacognosy occurs when dogs eat grass to induce vomiting. However, the behaviour is more diverse than this. Animals ingest or apply non-foods such as clay, charcoal and even toxic plants and invertebrates, apparently to prevent parasitic infestation or poisoning.
Whether animals truly self-medicate remains a somewhat controversial subject because early evidence is mostly circumstantial or anecdotal, however, more recent examinations have adopted an experimental, hypothesis-driven approach.
The methods by which animals self-medicate vary, but can be classified according to function as prophylactic (preventative, before infection or poisoning) or therapeutic (after infection, to combat the pathogen or poisoning). The behaviour is believed to have widespread adaptive significance.
Discussed on
- "Zoopharmacognosy" | 2014-08-07 | 32 Upvotes 6 Comments
π Hyperloop
A Hyperloop is a proposed mode of passenger and freight transportation, first used to describe an open-source vactrain design released by a joint team from Tesla and SpaceX. Hyperloop is a sealed tube or system of tubes through which a pod may travel free of air resistance or friction conveying people or objects at high speed while being very efficient, thereby drastically reducing travel times over medium-range distances.
Elon Musk's version of the concept, first publicly mentioned in 2012, incorporates reduced-pressure tubes in which pressurized capsules ride on air bearings driven by linear induction motors and axial compressors.
The Hyperloop Alpha concept was first published in August 2013, proposing and examining a route running from the Los Angeles region to the San Francisco Bay Area, roughly following the Interstate 5 corridor. The Hyperloop Genesis paper conceived of a hyperloop system that would propel passengers along the 350-mile (560Β km) route at a speed of 760Β mph (1,200Β km/h), allowing for a travel time of 35 minutes, which is considerably faster than current rail or air travel times. Preliminary cost estimates for this LAβSF suggested route were included in the white paperβUS$6 billion for a passenger-only version, and US$7.5 billion for a somewhat larger-diameter version transporting passengers and vehiclesβalthough transportation analysts had doubts that the system could be constructed on that budget; some analysts claimed that the Hyperloop would be several billion dollars overbudget, taking into consideration construction, development, and operation costs.
The Hyperloop concept has been explicitly "open-sourced" by Musk and SpaceX, and others have been encouraged to take the ideas and further develop them. To that end, a few companies have been formed, and several interdisciplinary student-led teams are working to advance the technology. SpaceX built an approximately 1-mile-long (1.6Β km) subscale track for its pod design competition at its headquarters in Hawthorne, California.
Discussed on
- "Hyperloop" | 2013-06-01 | 10 Upvotes 9 Comments
π 1 + 2 + 3 + .. = -1/12
Ramanujan summation is a technique invented by the mathematician Srinivasa Ramanujan for assigning a value to divergent infinite series. Although the Ramanujan summation of a divergent series is not a sum in the traditional sense, it has properties which make it mathematically useful in the study of divergent infinite series, for which conventional summation is undefined.
Discussed on
- "1 + 2 + 3 + .. = -1/12" | 2014-01-14 | 13 Upvotes 19 Comments
π Fourth, fifth, and sixth derivatives of position
In physics, the fourth, fifth and sixth derivatives of position are defined as derivatives of the position vector with respect to time β with the first, second, and third derivatives being velocity, acceleration, and jerk, respectively. Unlike the first three derivatives, the higher-order derivatives are less common, thus their names are not as standardized, though the concept of a minimum snap trajectory has been used in robotics and is implemented in MATLAB.
The fourth derivative is often referred to as snap or jounce. The name "snap" for the fourth derivative led to crackle and pop for the fifth and sixth derivatives respectively, inspired by the Rice Krispies mascots Snap, Crackle, and Pop. These terms are occasionally used, though "sometimes somewhat facetiously".
Discussed on
- "Fourth, fifth, and sixth derivatives of position" | 2023-02-25 | 27 Upvotes 3 Comments
π Java Card
Java Card is a software technology that allows Java-based applications (applets) to be run securely on smart cards and more generally on similar secure small memory footprint deviceswhich are called βsecure elementsβ (SE). Today, a Secure Element is not limited to its smart cards and other removable cryptographic tokens form factors; embedded SEs soldered onto a device board and new security designs embedded into general purpose chips are also widely used. Java Card addresses this hardware fragmentation and specificities while retaining code portability brought forward by Java.
Java Card is the tiniest of Java platforms targeted for embedded devices. Java Card gives the user the ability to program the devices and make them application specific. It is widely used in different markets: wireless telecommunications within SIM cards and embedded SIM, payment within banking cards and NFC mobile payment and for identity cards, healthcare cards, and passports. Several IoT products like gateways are also using Java Card based products to secure communications with a cloud service for instance.
The first Java Card was introduced in 1996 by Schlumberger's card division which later merged with Gemplus to form Gemalto. Java Card products are based on the specifications by Sun Microsystems (later a subsidiary of Oracle Corporation). Many Java card products also rely on the GlobalPlatform specifications for the secure management of applications on the card (download, installation, personalization, deletion).
The main design goals of the Java Card technology are portability, security and backward compatibility.
π The Panic of 1907
The Panic of 1907 β also known as the 1907 Bankers' Panic or Knickerbocker Crisis β was a financial crisis that took place in the United States over a three-week period starting in mid-October, when the New York Stock Exchange fell almost 50% from its peak the previous year. Panic occurred, as this was during a time of economic recession, and there were numerous runs on banks and trust companies. The 1907 panic eventually spread throughout the nation when many state and local banks and businesses entered bankruptcy. Primary causes of the run included a retraction of market liquidity by a number of New York City banks and a loss of confidence among depositors, exacerbated by unregulated side bets at bucket shops.
The panic was triggered by the failed attempt in October 1907 to corner the market on stock of the United Copper Company. When this bid failed, banks that had lent money to the cornering scheme suffered runs that later spread to affiliated banks and trusts, leading a week later to the downfall of the Knickerbocker Trust CompanyβNew York City's third-largest trust. The collapse of the Knickerbocker spread fear throughout the city's trusts as regional banks withdrew reserves from New York City banks. Panic extended across the nation as vast numbers of people withdrew deposits from their regional banks. It is the 9th largest decline in U.S. stock market history.
The panic might have deepened if not for the intervention of financier J. P. Morgan, who pledged large sums of his own money, and convinced other New York bankers to do the same, to shore up the banking system. This highlighted the impotence of the nation's Independent Treasury system, which managed the nation's money supply yet was unable to inject liquidity back into the market. By November, the financial contagion had largely ended, only to be replaced by a further crisis. This was due to the heavy borrowing of a large brokerage firm that used the stock of Tennessee Coal, Iron and Railroad Company (TC&I) as collateral. Collapse of TC&I's stock price was averted by an emergency takeover by Morgan's U.S. Steel Corporationβa move approved by anti-monopolist president Theodore Roosevelt. The following year, Senator Nelson W. Aldrich, a leading Republican, established and chaired a commission to investigate the crisis and propose future solutions, leading to the creation of the Federal Reserve System.
Discussed on
- "The Panic of 1907" | 2021-09-02 | 18 Upvotes 2 Comments
π Society for Preventing Parents from Naming Their Children Jennifer
The Society for Preventing Parents from Naming Their Children Jennifer (SPPNTCJ) was a popular and sometimes controversial website that contributed to early web culture, online from 1996 to 2000. The SPPNTCJ home page was created and updated by Jennifer Farwell, one of the three founding members of the SPPNTCJ. Other founding members were Jennifer Rich and Jennifer Ang.
The SPPNTCJ began as an inside joke on an email discussion list that both Farwell and Rich subscribed to, which included five or more Jennifers who actively posted at that time. One of the Jennifers tossed out the comment that there should be "a society for preventing parents from naming their children Jennifer." The idea took off, and Farwell created the SPPNTCJ's website. It welcomed more than 2 million visitors while online.
During its run, the SPPNTCJ was noted by the Richmond Times-Dispatch, Yahoo! Internet Life magazine, Thunder Bay Television News, 580 CKPR radio program Tech Talk, California State University, Chico, SignsOnSanDiego.com, WebMD and more. It received several Internet "cool site" acknowledgments, from Cool Central, Seven Wonders, Twoeys, Fallen Thinkers, and Secret Einstein.
Discussed on
- "Society for Preventing Parents from Naming Their Children Jennifer" | 2021-02-08 | 19 Upvotes 7 Comments