Daylight saving time in the Americas

Daylight saving time in the Americas is the arrangement in the Americas by which clocks are advanced by one hour in spring and moved back in autumn, to make the most of seasonal daylight. The practice is widespread in North America, with most of Canada, Mexico, and the United States of America participating, but much less so in South America.
North America.
Canada, Mexico, and the United States of America.
Canada, Mexico, and the United States of America use daylight saving time on a wide scale, with only a few states/provinces and parts thereof opting out of the practice or adopting it year-round without the twice yearly switch.
The United States territory of Puerto Rico remains in Atlantic Standard Time (AST) all year long.
Since 2007, in areas of Canada and the United States of America in which it is used, daylight saving time begins on the second Sunday of March and ends on the first Sunday of November. In Mexico, Congress has consistently been refusing to adopt this schedule on a nationwide basis, so only certain border cities in Mexican states that observe DST follow the same pattern as Canada and the United States of America. The rest of Mexico remains out of phase beginning DST on the first Sunday of April and ending on the last Sunday of October, the same schedule followed by Canada and the United States of America prior to 2007.
Saint Pierre and Miquelon.
Saint Pierre and Miquelon, located near the Canadian coast, belongs to France, but observes daylight saving time according to Canadian rules.
Greenland.
Greenland (excluding two minor areas at Danmarkshavn and Pituffik) observes DST and uses the European convention (DST begins 01:00 UTC last Sunday in March and ends 01:00 UTC last Sunday in October). Most populated places in the country are in the zone in the winter ( in the summer). Because of this, with respect to local time, clocks are changed from 22:00 to 23:00 in the spring (on the Saturday before the last Sunday in March), and reset back from 23:00 to 22:00 in the autumn (on the Saturday before the last Sunday in October).
Danmarkshavn does not use DST, because it is a weather station with an airstrip which is supplied from Iceland, which does not use DST. This might apply to some other weather stations in the area.
Pituffik/Thule Air Base uses and United States conventions on DST because it is a US air base, meaning it is part of the Atlantic Time Zone.
Bermuda.
Bermuda has observed DST annually since 1974.
The Caribbean lands.
Puerto Rico remains all year long in Atlantic Standard Time. (AST).
The Bahamas.
The Commonwealth of The Bahamas observes DST according to the American schedule.
Barbados.
Barbados in the western Atlantic no longer observes Daylight Saving Time, like many Caribbean nations. The last observance of a daylight saving-related time clock adjustment was between Sunday, 20 April 1980 at 2:00 AM – Thursday, 25 September 1980 at 2:00 AM. On 25 September the clock was shifted -3:00 – -4:00 where it has remained since.
Cuba.
Cuba normally observes DST from March to October although the precise dates vary. For two years in the mid-2000s (decade), Cuba stayed on DST throughout the year. In 2009 it was on DST from the second Sunday in March to the last Sunday of October. In 2011, it was on DST from the third Sunday in March to the second Sunday in November.
Dominica.
Dominica in the Caribbean does not observe Daylight Saving Time, like several other Caribbean nations.
The Dutch Caribbean Islands.
The Dutch Caribbean islands of Aruba, Bonaire, Curaçao, Saba, Sint Eustatius and Sint Maarten do not observe Daylight Saving Time.
The French Caribbean Islands.
The French Caribbean islands of Guadeloupe, Martinique, Saint-Barthélemy and Saint-Martin do not observe Daylight Saving Time.
Haiti.
Haiti had reestablished Daylight Saving Time in 2012, following the US/Canada DST Rules, starting on the second Sunday in March and ending on the first Sunday in November. This was discontinued in 2016,but was re-introduced in 2017.
Jamaica.
Jamaica previously used Daylight Saving Time, utilising the US and Canadian rules. The practise was used from 1974 before being discontinued in 1983.
Trinidad and Tobago.
Trinidad and Tobago remains on Atlantic Standard Time and does not observe DST.
The Turks and Caicos Islands.
Turks and Caicos discontinued Daylight Saving Time in March 2015, at the same time moving from the Eastern Time Zone to the Atlantic Time Zone, the end result being the same as having year-round Daylight Saving in the Eastern Time Zone.
In 2018, the islands reintroduced daylight saving time by setting the clocks back 1 hour to Eastern Standard Time; the islands follow the same daylight saving schedule as the United States of America and Canada.
Central America.
Guatemala.
Guatemala has used DST during energy crises. The last time it used DST was from April 30, 2006, to October 1, 2006.
Honduras.
Honduras adopted DST from May 1994 until September 1994 but then abandoned it. On May 7, 2006 it again used DST; however it ended on August 7, 2006, making this the shortest use of DST in the northern hemisphere as it was only applied for 3 months. The government decided not to use DST in 2007.
Nicaragua.
Nicaragua observed DST from January 1, 1992 until February 20, 1994 but it was stopped. On April 10, 2005 until October 2, 2005 DST was implemented, and the following year the period was similar, beginning on April 30, 2006 and ending on October 1, 2006; this measure was for energy conservation. In 2007, the government of Nicaragua decided to stop observing daylight saving time.
South America.
In equatorial regions, DST is not useful because of the stability of light levels throughout the year. As a result large areas of South America do not observe DST. DST is used in some of the more southerly countries such as Paraguay and most of Chile.
These countries or regions in South America do not use daylight saving time:
Argentina.
Since 2009, Argentina has not been observing DST and the entire country has stayed on . Argentina is located at a longitude that would naturally put it in the UTC−04:00 or UTC−05:00 time zone.
San Luis province, which was previously in a different time zone than most of the country and which formerly observed DST, decided in April 2010 not to change its clocks back and to stay on all year round.
The most recent history of Argentina observing DST dates from 2007 to 2009. After a period of not observing DST, Argentina observed DST in some provinces in an attempt to save energy. For each period, the executive branch of the government set the specific start and end dates for DST, i.e. there was no fixed annual schedule.
Bolivia.
In 2011, Bolivia planned to observe DST starting September 1 for the first time in its history, advancing the clock an hour on a nationwide basis in order to offset their energy problems. The schedule change was planned to take place every year between September and March, corresponding to the spring and summer of the South American country. However, the day before the scheduled change, on August 31, 2011, the national government indefinitely suspended the observation of DST due to opposition from experts in electricity, neighborhood and school leaders, and the general populace.
Brazil.
Brazil adopted DST (called "horário de verão"—"summer time"—in Portuguese) for the first time in 1931, and it was in effect across the entire country. The duration and regional applicability of DST has varied over the years (see for details). As of 2013, DST was used only in the southern region (the states of Rio Grande do Sul, Santa Catarina, Paraná), the southeast region (the states of São Paulo, Rio de Janeiro, Espirito Santo, Minas Gerais), and the central-west region (the state of Goiás and the Distrito Federal, and the states of Mato Grosso and Mato Grosso do Sul).
Formerly, starting and ending dates were variable, but in 2008, a decree (No. 6558 of 9 September 2008) established a permanent rule: DST starts at 00:00 on the third Sunday in October from 2008 to 2017 (and on the first Sunday in November from 2018 to the present), and ends at 00:00 on the third Sunday in February—unless the latter falls during Carnaval: in this case, the end of DST was postponed by one week.
In 2019, Brazil scrapped daylight saving time and now stays on standard time year round.
Chile.
Chile currently observes DST from the first Saturday in September to the first Saturday in April.
In the past, DST was observed from the second Saturday in October to the second Saturday in March, but it has varied (see Time in Chile). In 2008, for example, the time was adjusted on Sunday, March 30, at 12 midnight.
In 2010, because of an earthquake, DST remained in effect until April 3.
In 2011, in order to prevent energy shortages after a dry summer, DST was first extended until April 2 and then until May 7.
From 2011-2014, Chile DST started the first Saturday of September at 24:00, and ended the last Saturday of April at 24:00.
DST was not observed in 2015 when the government declared that the country would remain on permanently. But on March 16, 2016, decree 253 modified the 2015 decision and restored winter time. It would last 90 days from the second weekend of May to the second weekend of August.
Colombia.
From February 1992 until March 1993, Colombia suffered rolling blackouts of up to 10 hours a day due to a particularly strong El Niño season, which dried the reservoirs in hydroelectric plants in a country deriving 70% of its energy output from hydroelectric sources; consequently, the government decided to use DST to help save electricity. The experiment failed to deliver the intended results, possibly due to Colombia's low latitude, and the DST experiment was discontinued.
Ecuador.
Ecuador's President Sixto Durán Ballén imposed daylight saving time in 1992 in an energy-saving effort. It was poorly received by the populace and did not last long.
Falkland Islands.
DST () is generally observed from the first Sunday of September to the third Sunday of April. However, the Falklands remained on DST throughout 2011 and 2012.
Paraguay.
Paraguay observes DST under decree 1867 of March 5, 2004. DST ends on the second Sunday of March and starts on the third Sunday of October.
In 2007, DST started on October 15, 2006 and ended on March 11, 2007.
In 2010, Paraguay changed its own DST rules because of the energy crisis, ending DST on the second Sunday in April, a month later than previous years. The start date remains unchanged.
Uruguay.
Since 2004, Uruguay has observed DST. Starting in 2006, DST begins on the first Sunday in October and ends on the second Sunday in March of every year. On 30 June 2015, Uruguay abolished DST.


Safe semantics

Safe semantics is a computer hardware consistency model. It describes one type of guarantee that a data register provides when it is shared by several processors in a parallel computer or in a network of computers working together.
History.
Safe semantics was first defined by Leslie Lamport in 1985. It was formally defined in Lamport's "On Interprocess Communication" in 1986.
Safe register has been implemented in many distributed systems.
Description.
Safe semantics are defined for a variable with a single writer but multiple readers (SWMR). A SWMR register is safe if each read operation satisfies these properties:
In particular, given concurrency of a read and a write operation, the read can return a value that has not been written by a write. The return value need only belong to the register domain.
A binary safe register can be seen as modeling a bit flickering. Whatever the previous value of the register is, its value could flicker until the write finishes. Therefore, the read that overlaps with a write could return 0 or 1.
"Churn" refers to the entry and exit of servers to/from a distributed system. Baldoni et al. show that no register can have the stronger property of regular semantics in a synchronous system under continuous churn. However, a safe register can be implemented under continuous churn in a non-synchronous system. Modeling and implementing a type of storage memory (Safe Register) under non-quiescent churn requires some system models such as client and server systems. Client systems contains a finite, arbitrary number of processes that are responsible for reading and writing the server system. However,the server system must ensure that read and write operations happen properly.
Implementation.
Safe register implementation involves:
Safe register is maintained by the set of active servers.
Clients maintain no register information.
Eventually synchronous system
Quora (set of server or client systems)
Size of the Read and Write operation executed on quora = n – f – J (n is the number of servers, J is the number of servers that enter and exit, and f is the number of Byzantine failures.
Algorithms such as join, read, and write.
Join.
A server ("si") that wants to enter a server system broadcasts an inquiry message to other servers to inform them of its entry, si requests a current value of the register. Once other server receive this inquiry they send reply messages to si. After si receives enough replies from other servers, it collects the replies and saves them into a reply set. Si waits until it gets enough replies (n-f-j) from other servers then it picks the most frequently received value. Si also:
Read.
The read algorithm is a basic version of join. The difference is the broadcast mechanism used by the read operation. A client ("cw") broadcasts a message to the system and once a server receives the inquiry, it sends a reply message to the client. Once the client receives enough replies (n-f-j) it stops sending an inquiry.
Write.
Client ("cw") sends an inquiry into the system in different rounds and waits until it receives two acknowledgment. ("sn" =sequence number)
The reason for receiving two acknowledgments is to avoid danger in a system. When a process sends an acknowledgement ("ack"), it may die after one millisecond. Therefore, no confirmation is received by the client.
The validity of the safe register (If a read is not concurrent with any write, return the last value written) was proved based on the quorum system. Given two quorum systems (Qw, Qr) Qw indicates the servers that know about the latest value, and Qr indicates values of read responses. The size of each quorum is equal to n-f-j. Proving the safe register's validity requires proving
formula_1
were "B" is the number of Byzantine failures.
Proof : Red region indicates (Qw∩Qr)\B and the blue region indicates Qr∩B. From the assumption, the size of each quorum is n-f-j, so the red region has n-3f-2j active servers. Therefore,
formula_2is strictly greater than f.


Noon mark

The Noon mark is a type of sundial that at its simplest is a vertical line on a south facing wall or a north-south line on a horizontal pavement. When the shadow of a point (or a projected image of the Sun) crosses the line it will be midday. Noon in local standard time is defined as when the sun is overhead, however clocks and watches use mean time which varies from standard time by a few minutes each day. The difference is calculated using the equation of time and this can be shown on the noon mark by drawing an analemma, or using a correction table.


Evaporative light scattering detector

An evaporative light scattering detector (ELSD) is a detector used in conjunction with high-performance liquid chromatography (HPLC), Ultra high-performance liquid chromatography (UHPLC), Purification liquid chromatography such as flash or preparative chromatography, countercurrent or centrifugal partition chromatographies and Supercritical Fluid chromatography (SFC). It is commonly used for analysis of compounds where UV detection might be a restriction and therefore used where compounds do not efficiently absorb UV radiation, such as sugars, antivirals, antibiotics, fatty acids, lipids, oils, phospholipids, polymers, surfactants, terpenoids and triglycerides. ELSDs is related to the charged aerosol detector (CAD) and like the CAD, falls under the category of destructive detectors.
An evaporative light scattering detector (ELSD) is able to detect all compound which are less volatile than the mobile phase, i.e. non volatile and semi-volatile compounds.
Principles of operation.
ELSDs analyze solvent after elution from HPLC. As the eluent passes from an HPLC, it is mixed with an inert carrier gas and forced through a nebulizer, which separates the liquid into minute aerosolized droplets. These droplets then pass into a heated drift tube, where the mobile phase solvent is evaporated off. As the mobile phase evaporates, the droplets become smaller and smaller until all that is left is minute particles of dried analyte. These particles are pushed through the drift tube by the carrier gas to the detection region. In this region, a beam of light crosses the column of analyte and the scattering of light is measured by a photodiode or photomultiplier tube. The detector's output is non-linear across more than one order of magnitude and proper calibration is required for quantitative analysis.


3367 Alex

3367 Alex, provisional designation "", is a background asteroid from the intermediate region of the asteroid belt, approximately in diameter. It was discovered on 2 September 1993, by American astronomer Norman Thomas at Lowell's Anderson Mesa Station, near Flagstaff, Arizona, in the United States. The X-type asteroid has a rotation period of 9.6 hours. It was named after the grandson of the discoverer, Alex Baltutis.
Orbit and classification.
"Alex" is a non-family asteroid from the main belt's background population. It orbits the Sun in the central asteroid belt at a distance of 2.6–3.0 AU once every 4 years and 8 months (1,697 days). Its orbit has an eccentricity of 0.07 and an inclination of 5° with respect to the ecliptic. The asteroid was first identified as "" at Heidelberg Observatory in 1953, extending the body's observation arc by 30 years prior to its official discovery observation at Anderson Mesa.
Naming.
This minor planet was named by the discoverer after his grandson, Alex R. Baltutis. The official naming citation was published by the Minor Planet Center on 26 March 1986 ().
Physical characteristics.
In the SMASS classification, "Alex" is an X-type asteroid, while NASA's Wide-field Infrared Survey Explorer characterizes it as a bright E-type asteroid. Due to its intermediate albedo, the body may be of metallic composition.
Rotation period.
In February 2006 and April 2011, two rotational lightcurves of "Alex" were obtained from photometric observations made by French astronomers René Roy and Laurent Bernasconi, respectively. The fragmentary lightcurves gave an identical rotation period of and hours with a respective brightness variation of 0.01 and 0.05 in magnitude (). Such a low amplitude typically indicates that the body has a nearly spheroidal shape.
Diameter and albedo.
According to the space-based surveys carried out by the Japanese Akari satellite and by WISE with its subsequent NEOWISE mission, "Alex" has an albedo of 0.10, and measures 17.0 and 15.2 kilometers in diameter, respectively. The "Collaborative Asteroid Lightcurve Link" assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 19.3 kilometers with an absolute magnitude of 12.3.


Analysis of daylight saving time

Daylight saving time (DST) is the practice of advancing clocks during warmer months so that darkness falls later each day according to the clock.
Proponents of DST generally argue that it saves energy, promotes outdoor leisure activity in the evening (in summer), and is therefore good for physical and psychological health, reduces traffic accidents, reduces crime or is good for business.
Opponents argue that DST disrupts human circadian rhythms (negatively impacting human health in the process), that it increases fatal traffic collisions, that the actual energy savings are inconclusive, and that DST increases health risks such as heart attack. Farmers have tended to oppose DST.
Having a common agreement about the day's layout or schedule has so many advantages that a standard schedule over whole countries or large areas has generally been chosen over efforts in which some people get up earlier and others do not. The advantages of coordination are so great that many people ignore whether DST is in effect by altering their work schedules to coordinate with television broadcasts or daylight. DST is commonly not observed during most of winter, because the days are shorter then; workers may have no sunlit leisure time, and students may need to leave for school in the dark. Since DST is applied to many varying communities, its effects may be very different depending on their culture, light levels, geography, and climate. Because of this variation, it is hard to make generalized conclusions about the effects of the practice. The costs and benefits may differ between places. Some areas may adopt DST simply as a matter of coordination with other areas rather than for any other benefits.
Energy use.
A 2017 meta-analysis of 44 studies found that DST leads to electricity savings of 0.3% during the days when DST applies. The meta-analysis furthermore found that "electricity savings are larger for countries farther away from the equator, while subtropical regions consume more electricity because of DST." This means that DST may conserve electricity in some countries, such as Canada and the United Kingdom, but be wasteful in other places, such as Mexico, the southern United States, and northern Africa. The savings in electricity may also be offset by extra use of other types of energy, such as heating fuel.
The period of daylight saving time before the longest day is shorter than the period after, in several countries including the United States of America, in areas that observe daylight saving time, and Europe. For example, in the U.S. the period of daylight saving time is defined by the Energy Policy Act of 2005. The period for daylight saving time was extended by changing the start date from the first Sunday of April to the second Sunday of March and changing the end date from the last Sunday in October to the first Sunday in November.
DST's potential to save energy comes primarily from its effects on residential lighting, which consumes about 3.5% of electricity in the United States and Canada. (For comparison, air conditioning uses 16.5% of energy in the United States.) Delaying the nominal time of sunset and sunrise reduces the use of artificial light in the evening and increases it in the morning. As Franklin's 1784 satire pointed out, lighting costs are reduced if the evening reduction outweighs the morning increase, as in high-latitude summer when most people wake up well after sunrise. An early goal of DST was to reduce evening usage of incandescent lighting, once a primary use of electricity. Although energy conservation remains an important goal, energy usage patterns have greatly changed since then. Electricity use is greatly affected by geography, climate, and economics, so the results of a study conducted in one place may not be relevant to another country or climate.
Several studies have suggested that DST increases motor fuel consumption. The 2008 DOE report found no significant increase in motor gasoline consumption due to the 2007 United States extension of DST.
Economic effects.
Those who benefit most from DST are the retailers, sporting goods makers, and other businesses that benefit from extra afternoon sunlight. Having more hours of sunlight in between the end of the typical workday and bedtime induces customers to shop and to participate in outdoor afternoon sports. People are more likely to stop by a store on their way home from work if the sun is still up. In 1984, "Fortune" magazine estimated that a seven-week extension of DST would yield an additional $30 million for 7-Eleven stores, and the National Golf Foundation estimated the extension would increase golf industry revenues $200 million to $300 million. A 1999 study estimated that DST increases the revenue of the European Union's leisure sector by about 3%.
Conversely, DST can harm some farmers, and others whose hours are set by the sun. One reason why farmers oppose DST is that grain is best harvested after dew evaporates, so when field hands arrive and leave earlier in summer, their labor is less valuable. Dairy farmers are another group who complain of the change. Their cows are sensitive to the timing of milking, so delivering milk earlier disrupts their systems. Today some farmers' groups are in favor of DST.
Young children often have difficulty getting enough sleep at night when the evenings are bright.
DST also hurts prime-time television broadcast ratings, drive-ins and other theaters.
Changing clocks and DST rules has a direct economic cost, entailing extra work to support remote meetings, computer applications and the like. For example, a 2007 North American rule change cost an estimated $500 million to $1 billion, and Utah State University economist William F. Shughart II has estimated the lost opportunity cost at around US$1.7 billion. Although it has been argued that clock shifts correlate with decreased economic efficiency, and that in 2000 the daylight-saving effect implied an estimated one-day loss of $31 billion on U.S. stock exchanges, the estimated numbers depend on the methodology. The results have been disputed, and the original authors have refuted the points raised by disputers.
Public safety.
In 1975 the United States Department of Transportation (DOT) conservatively identified a 0.7% reduction in traffic fatalities during DST, and estimated the real reduction at 1.5% to 2.0%, but the 1976 NBS review of the DOT study found no differences in traffic fatalities. In 1995 the Insurance Institute for Highway Safety estimated a reduction of 1.2%, including a 5.0% reduction in crashes fatal to pedestrians. Others have found similar reductions. Single/Double Summer Time (SDST), a variant where clocks are one hour ahead of the sun in winter and two in summer, has been projected to reduce traffic fatalities by 3% to 4% in the UK, compared to ordinary DST. However, accidents do increase by as much as 11% during the two weeks that follow the end of British Summer Time. It is not clear whether sleep disruption contributes to fatal accidents immediately after the spring clock shifts. A correlation between clock shifts and traffic accidents has been observed in North America and the UK but not in Finland or Sweden. Four reports have found that this effect is smaller than the overall reduction in traffic fatalities. A 2009 U.S. study found that on Mondays after the switch to DST, workers sleep an average of 40 minutes less, and are injured at work more often and more severely.
DST likely reduces some kinds of crime, such as robbery and sexual assault, as fewer potential victims are outdoors after dusk. Artificial outdoor lighting has a marginal and sometimes even contradictory influence on crime and fear of crime.
In several countries, fire safety officials encourage citizens to use the two annual clock shifts as reminders to replace batteries in smoke and carbon monoxide detectors, particularly in autumn, just before the heating and candle season causes an increase in home fires. Similar twice-yearly tasks include reviewing and practicing fire escape and family disaster plans, inspecting vehicle lights, checking storage areas for hazardous materials, reprogramming thermostats, and seasonal vaccinations. Locations without DST can instead use the first days of spring and autumn as reminders.
A 2017 study in the "American Economic Journal: Applied Economics" estimated that "the transition into DST caused over 30 deaths at a social cost of $275 million annually," primarily by increasing sleep deprivation.
Using a large US database of 732,835 fatal motor vehicle accidents (MVA) recorded from 1996 to 2017, Fritz et al. (2019) found a 6% increase in fatal MVA risk in the workweek following the spring transition to DST, which was more pronounced in the morning and further West of a time zone. There were no effects of the fall-back transition to standard time (ST) on MVA risk, supporting the hypothesis that circadian misalignment and sleep deprivation underlie MVA risk increases.
In March 2020, the Israeli government planned to delay daylight saving in order to discourage gatherings during the COVID-19 pandemic. However, it was decided this would be too technically difficult to implement at such short notice.
Health.
Experts in circadian rhythms and sleep are warning about the negative health implications of DST. DST cuts on sleep and causes an increased mismatch between the body clock and local time, a condition called social jetlag. Both sleep deprivation and social jetlag have been associated with negative effects on physical and mental health outcomes, including increased risks for diabetes, obesity, heart disease, depression, and some forms of cancer. Year-round standard time (not year-round DST) is proposed to be the preferred option for public health and safety.
In societies with fixed work schedules it provides more afternoon sunlight for outdoor exercise. It alters sunlight exposure; the effects depend on one's location and daily schedule, as sunlight triggers vitamin D synthesis in the skin, but overexposure can lead to skin cancer. DST may help in depression by causing individuals to rise earlier, but some argue the reverse. The Retinitis Pigmentosa Foundation Fighting Blindness, chaired by blind sports magnate Gordon Gund, successfully lobbied in 1985 and 2005 for U.S. DST extensions. DST shifts are associated with higher rates of ischemic stroke in the first two days after the shift, though not in the week thereafter.
Clock shifts were found to increase the risk of heart attack by 10 percent, and to disrupt sleep and reduce its efficiency. Effects on seasonal adaptation of the circadian rhythm can be severe and last for weeks. A 2008 study found that although male suicide rates rise in the weeks after the spring transition, the relationship weakened greatly after adjusting for season. A 2008 Swedish study found that heart attacks were significantly more common the first three weekdays after the spring transition, and significantly less common the first weekday after the autumn transition. A 2013 review found little evidence that people slept more on the night after the fall DST shift, even though it is often described as allowing people to sleep for an hour longer than normal. The same review stated that the lost hour of sleep resulting from the spring shift appears to result in sleep loss for at least a week afterward. Even so, a 2014 study conducted in the United States showed that heart attacks decreased significantly after the fall DST shift.
The government of Kazakhstan cited health complications due to clock shifts as a reason for abolishing DST in 2005. In March 2011, Dmitri Medvedev, president of Russia, claimed that "stress of changing clocks" was the motivation for Russia to stay in DST all year long. Officials at the time talked about an annual increase in suicides.
An unexpected adverse effect of daylight saving time may lie in the fact that an extra part of morning rush hour traffic occurs before dawn and traffic emissions then cause higher air pollution than during daylight hours.
In 2017, researchers at the University of Washington and the University of Virginia reported that judges who experienced sleep deprivation as a result of DST tended to issue longer sentences.
Complexity and disadvantages.
DST's clock shifts have the obvious disadvantage of complexity. People must remember to change their clocks; this can be time-consuming, particularly for mechanical clocks that cannot be moved backward safely. People who work across time zone boundaries need to keep track of multiple DST rules, as not all locations observe DST or observe it the same way. The length of the calendar day becomes variable; it is no longer always 24 hours. Disruption to meetings, travel, broadcasts, billing systems, and records management is common, and can be expensive. During an autumn transition from 02:00 to 01:00, a clock reads times from 01:00:00 through 01:59:59 twice, possibly leading to confusion.
Lists of time zones and time differences usually do not include daylight saving time, as that is considered complicated and would mean different times over the seasons of the year. For example, UK is usually listed as UTC±00:00, Japan as , and Sydney as . But in January, Sydney observes , and in July, UK observes UTC+01:00, so the differences between all these countries vary during the year. Since lists avoid taking complicated daylight saving time into account, they give wrong information about actual time.
Damage to a German steel facility occurred during a DST transition in 1993, when a computer timing system linked to a radio time synchronization signal allowed molten steel to cool for one hour less than the required duration, resulting in spattering of molten steel when it was poured. Medical devices may generate adverse events that could harm patients, without being obvious to clinicians responsible for care. These problems are compounded when the DST rules themselves change; software developers must test and perhaps modify many programs, and users must install updates and restart applications. Consumers must update devices such as programmable thermostats with the correct DST rules or manually adjust the devices' clocks. A common strategy to resolve these problems in computer systems is to express time using the Coordinated Universal Time with no offset (UTC±00:00; which, depending on time of year, is not always the same as hour as London time) rather than the local time zone. For example, Unix-based computer systems use the UTC-based Unix time internally.
Some clock-shift problems could be avoided by adjusting clocks continuously or at least more gradually—for example, Willett at first suggested weekly 20-minute transitions—but this would add complexity and has never been implemented.
DST inherits and can magnify the disadvantages of standard time. For example, when reading a sundial, one must compensate for it along with time zone and natural discrepancies. Also, sun-exposure guidelines such as avoiding the sun within two hours of noon become less accurate when DST is in effect.


Lenore E. Bixby

Lenore Alice Epstein Bixby (August 12, 1914 – April 5, 1994) was an American statistician who worked with the Social Security Administration and the National Academy of Sciences.
Education.
She was born in Buffalo, New York, and some of her earlier publications are listed under that name. As a student of the class of 1935 at Wellesley College, she became chairman of the school's branch of the League of Women Voters, and graduated Phi Beta Kappa with honors as a Senior Durant Scholar.
She did graduate study in economics and statistics at Columbia University, earning a master's degree there in 1937.
Career.
After completing her studies, she came to work for the Bureau of Labor Statistics and then, after World War II, as an operations officer for the Marshall Plan. This work took her away from Washington to Paris.
She joined the Social Security Administration in 1954,
and worked there as deputy assistant commissioner of the Office of Research and Statistics and later as director of the Division of Retirement and Survivors' Studies.
While there, she married F. Lovell Bixby, a prominent penologist, who died in 1975.
She retired from the administration in 1977, but continued to work as a statistician for the National Academy of Sciences, in their Committee on National Statistics.
Awards and honors.
In 1969, she was honored by the American Statistical Association, who elected her as one of their fellows. She was also a fellow of the Gerontological Society. She was a founding member of the National Academy of Social Insurance.


Kinnordy House

Kinnordy House (alternative spellings: Kynnordy, Kinardy, Kinnordie and Kinorde) is an estate house near Kirriemuir in Angus, Scotland. The first house was built in the 1680s, when Inverquharity Castle was vacated; however, the current three-storey, towered and turreted structure dates from 1881, incorporating an 18th-century wing and stables. The house was the birthplace of the noted geologist Charles Lyell, and is associated with his friend Charles Darwin.
History.
The walled garden was built after the Jacobite rising of 1745, by the "Nameless Highlanders".
On 28 November 1782 the entrepreneur Charles Lyell bought Inverquharity and Kinnordy from Sir John Ogilvy. An observatory was added by his son, the botanist Charles Lyell.
The house was designated a Category B listed building in 1980. Many of the associated buildings and structures are also listed: the home farm, the East Lodge and its gates, the Causewayend Cottages (now the Kinnordy Estate Office), the museum and observatory, the walled garden, sundial and Bell Gate.


638 Moira

638 Moira, also known as A907 JG, is a minor planet orbiting the Sun. First observed in 1906, 638 Moira was discovered to be an orbital body in 1907 by Joel Hastings Metcalf in Taunton, England. 638 Moira is a little over 59.5 km across and rotates once every 10 hours. Its farthest point from the sun is a little over 3au during its 4.5 year orbit, and it is classed as an L-type asteroid (SMASSII).


6354 Vangelis


Uruguayan units of measurement

A number of units of measurement were used in Uruguay to measure quantities. Metric system was optional in Uruguay since 1866, and has been compulsory since 1894.
System before metric system.
The older system was the Spanish (Castilian) system with some modification.
Mass.
One libra was equal to 460 g (1.014286 lb).
Capacity.
One fanega was equal to 274 l (7.776 bushels).


Cantilever magnetometry

Cantilever magnetometry is the use of a cantilever to measure the magnetic moment of magnetic particles. On the end of cantilever is attached a small piece of magnetic material, which interacts with external magnetic fields and exerts torque on the cantilever. These torques cause the cantilever to oscillate faster or slower, depending on the orientation of the particle's moment with respect to the external field, and the magnitude of the moment. The magnitude of the moment and magnetic anisotropy of the material can be deduced by measuring the cantilever's oscillation frequency versus external field.
A useful, although limited analogy is that of a pendulum: on earth it oscillates with one frequency, while the same pendulum on, say, the moon, would oscillate with a slower frequency. This is because the mass on the end of the pendulum interacts with the external gravitational field, much as a magnetic moment interacts with an external magnetic field.
Cantilever equation of motion.
As the cantilever oscillates back and forth it arches into hyperbolic curves with the salient feature that a tangent to the end of the cantilever always intersects one point along the middle axis. From this we define the effective length of the cantilever, formula_1, to be the distance from this point to the end of the cantilever (see image to the right). The Lagrangian for this system is then given by
_{v^2}-\left(\underbrace{\frac{1}{2}k ( L_{e} \theta )^{2}}_{\begin{smallmatrix}\text{Restoring}\\ \text{Energy}\end{smallmatrix}}-\underbrace{\mu B \cos{(\theta-\beta)}}_{\begin{smallmatrix}\text{Zeeman}\\ \text{Energy}\end{smallmatrix}}+\underbrace{K_uV\sin^2{\beta}}_{\begin{smallmatrix}\text{Anisotropy}\\ \text{Energy}\end{smallmatrix}}\right)
where formula_2 is the effective cantilever mass, formula_3 is the volume of the particle, formula_4 is the cantilever-constant and formula_5 is the magnetic moment of the particle. To find the equation of motion we note that we have two variables, formula_6 and formula_7 so there are two corresponding Lagrangian equations which need to be solved as a system of equations,
where we have defined formula_9.
We can plug Eq. 1 into our Lagrangian, which then becomes a function of formula_6 only. Then formula_11, and we have
formula_15
or
where formula_16. The solution to this differential equation is formula_17 where formula_18 and formula_19 are coefficients determined by the initial conditions. The motion of a simple pendulum is similarly described by this differential equation and solution in the small angle approximation.
We can use the binomial expansion to rewrite formula_20,
which is the form as seen in literature, for example equation 2 in the paper "Magnetic Dissipation and Fluctuations in Individual Nanomagnets Measured
by Ultrasensitive Cantilever Magnetometry".


Brooklyn Underground Film Festival

The Brooklyn Underground Film Festival was an annual showcase of typically low-budget, under-distributed or amateur videos and metavideos. The festival was initially held in DUMBO, Brooklyn and later moved to Park Slope neighborhood of Brooklyn, New York. The festival ran from 2002-2007.
The festival also showed the work of emerging non-media artists. The first festival included a large wheat paste mural by the artist known as Swoon.
History.
The festival was founded in 2002 by graduates of Pratt Institute, Josh Koury, Myles Kane, Cris Moris and Gaia Cornwall. It was funded in part by a growing number of local businesses.
The festival ceased operations in 2007.


Zoharei Chama Synagogue

Zoharei Chama Synagogue (, literally, "Sunrise Synagogue"), also spelled Zohorei Chama, colloquially known as the Sundial Building or Mahane Yehuda Clock Tower, is a three-story stone building with a wooden attic on Jaffa Road in Jerusalem, Israel, which features a huge, diameter sundial on its façade. The building, constructed in stages by Rabbi Shmuel Levy from 1908 to 1917, was built to house a hostel for immigrants and a synagogue. It was damaged by fire in 1941 and partly restored by the Jerusalem municipality in 1980. Today it still houses the Zoharei Chama Orthodox synagogue, which has prayer services throughout the day for local businessmen, residents and tourists.
History.
The tall, narrow building, which towers over the neighboring structures, was constructed by Rabbi Shmuel Levy, an American tailor who immigrated to Israel from the United States at the beginning of the 20th century. In 1906 he purchased a one-story house in the Mahane Yehuda neighborhood on Jaffa Road with the intention of adding to it in stages and providing rooms for immigrants as a public service. He raised money for the construction in America by selling lottery tickets for 20 francs apiece, awarding two grand prizes of 2,000 francs each and other prizes of 1,000, 500, 100, 50, and 20 francs. The tickets depicted the planned three-story building with a fourth-floor attic and fifth-floor gallery, together with pictures of the Four Holy Cities in Jewish tradition—Jerusalem, Hebron, Tiberias and Safed—and a written description of Levy's goals to build a synagogue, study hall and hostel.
Completed in stages from 1908 to 1917, Levy's three-story stone building with attic and gallery was the tallest in Jerusalem for its time. After construction was complete, Levy consecrated the upper floor as the Zoharei Chama (Sunrise) Synagogue for worshippers who prayed at sunrise ("vasikin") and also provided a beth midrash called Shoneh Halakhos (literally, "Review of Jewish Laws"). The Tiferet Zion V'yerushalayim (Glory of Zion and Jerusalem) Hostel on the lower floors accommodated 50 guests. The large sundial was added later to the fourth-story façade.
In 1927 the fifth-floor gallery collapsed during an earthquake. In 1941, an electrical short circuit ignited a fire that spread throughout the building, destroying the gallery and damaging the rest of the building together with the sundial and clocks.
In 1980 the Jerusalem municipality restored the façade and reconstructed the sundial. The Zoharei Chama Synagogue is now the only tenant, with afternoon prayer services held one after another on the first floor and continuous evening prayer services conducted on the second floor. Women are not allowed in the synagogue. The building also has a "Shabbat siren" posted on its roof, which alerts residents to the time of lighting Shabbat candles.
Sundial.
The vertical sundial on the fourth floor of the building was designed by Rabbi Moshe Shapiro, a watchmaker in Mea Shearim and a self-taught astronomer who had learned the science by studying the pertinent writings of Maimonides and the Vilna Gaon. Shapiro had built sundials for the outside walls of other synagogues, such as the Hurva Synagogue in Jerusalem's Old City, and would go on to build sundials for at least 15 other synagogues in Israel, including Petah Tikva's Great Synagogue.
Sundials were of crucial use for Orthodox synagogue-goers who needed to know the exact time of sunrise to begin their morning prayers ("vasikin"), the exact time of sunset to complete their afternoon prayers, and the time for lighting Shabbat candles, since these times vary day by day and season by season. Before the Zoharei Chama sundial was erected, Orthodox Jews would climb to the top of the Mount of Olives or the hills of the Bayit Vegan neighborhood each morning and evening to observe the times of sunrise and sunset. The third floor of Levy's building originally included an eastern-facing wooden porch which allowed worshippers to easily see the sunrise.
The Zoharei Chama sundial measures in diameter. A horizontal gnomon marks the sun's progress along a half-circle marked at each hour, with sub-markings at 15, 30, and 45 minutes. For cloudy days, Levy installed two mechanical clocks on either side of the sundial, one set for European time and one for local time. Shapiro also designed three sundials for the third floor of the building. Only the large sundial on the fourth floor is still extant.
The sundial was featured on a December 2014 Israeli postage stamp that was part of a 3 stamp series titled Sundials in Eretz Israel.


Expanding nozzle

The expanding nozzle is a type of rocket nozzle that, unlike traditional designs, maintains its efficiency at a wide range of altitudes. It is a member of the class of altitude compensating nozzles, a class that also includes the plug nozzle and aerospike. While the expanding nozzle is the least technically advanced and simplest to understand from a modeling point of view, it also appears to be the most difficult design to build.
In the traditional bell nozzle the engine skirt is shaped to gradually flare out from the small-diameter exit from the combustion chamber, growing larger further from the chamber. The basic idea is to lower the pressure of the exhaust by expanding it in the nozzle, until it reaches ambient air pressure at the exit. For operations at sea level
the skirt is generally short and highly angled, at least in comparison to a skirt designed for operations in space, which are longer and more gradually shaped. This means that a rocket engine that spends any significant amount of time climbing through the atmosphere cannot be optimally shaped; as it climbs the ambient pressure changes, so the exact shape and length of the skirt would have to change in order to maintain the proper pressure. Rocket designers have to select the sweet spot that is most appropriate to their needs, realizing that this will reduce thrust by as much as 30% at other altitudes.
The expanding nozzle addresses this to a degree by including two skirts on a single engine, one inside the other. The first skirt, attached directly to the combustion chamber, is designed for use at lower altitudes and is short and squat. The second, sitting outside the first, fits over the lower altitude bell to extend it into a longer and narrower (measured in terms of length) bell used for higher altitudes. At liftoff the outer bell is pulled up from the inner bell, out of the way of the exhaust. As the spacecraft climbs, the outer bell is pushed back down over the inner bell to increase the thrust efficiency. Thus an expanding nozzle can have two sweet spots, which can lead to a major improvement in overall performance.
Generally simple in concept, the expanding nozzle is considerably more complex to build than it might seem. Engine bells must be cooled to avoid damage from the hot rocket exhaust, and this has presented problems in expanding nozzle designs. The cooling is normally accomplished by running either the oxidizer or fuel (in the case of LH2 fueled engines) through tubing in the bell. With the bell moving, plumbing carrying the coolant to the bell has to be flexible and this increases complexity to the extent that the advantages of the design are often considered too costly. In the case of liquid hydrogen, the fluid also has the disadvantage of being highly reactive chemically, making a variety of common flexible materials unsuitable for use in this role.
For the aforementioned reasons modern designs (e. g. NK-33-1, RL-10A-4, and RL-10B-2) feature radiatively cooled reinforced carbon–carbon nozzle extensions needing no coolant plumbing at all.
The first engine design to include an expanding nozzle appears to be the Pratt & Whitney XLR-129. The XLR-129 was intended to power a McDonnell Aircraft boost-glide aircraft design that was entered as part of the Project ISINGLASS (or RHEINBERRY) study looking at follow-on designs to replace the Lockheed A-12 that was just entering service. It was a liquid oxygen/liquid hydrogen design that used staged combustion and generated about thrust. An enlarged version of the XLR-129 was proposed for the Space Shuttle Main Engine contest, but this was won by the RS-25, an enlarged Rocketdyne HG-3. Since these engines are fired from the point of liftoff into extra-atmospheric space flight, any sort of altitude compensation could dramatically improve their overall performance. The expanding nozzle was later abandoned in a cost-cutting phase, and the RS-25 suffers a 25% loss of performance at low altitude as a result.
Glushko has used an expanding nozzle on one design, the RD-701 tripropellant rocket. Funding ran out with the fall of the Soviet state, but the designers are convinced the engine has potential and have approached several parties for additional funding.


Scale ruler

A scale ruler is a tool for measuring lengths and transferring measurements at a fixed ratio of length; two common examples are an architect's scale and engineer's scale. In scientific and engineering terminology, a device to measure linear distance and create proportional linear measurements is called a scale. A device for drawing straight lines is a straight edge or ruler. In common usage, both are referred to as a ruler.
Architect's scale.
An architect's scale is a specialized ruler designed to facilitate the drafting and measuring of architectural drawings, such as floor plans and Multi-view orthographic projections.
Because the scale of such drawings are often smaller than life-size, an architect's scale features multiple units of length and proportional length increments.
For accuracy and longevity, the material used should be dimensionally stable and durable. Scales were traditionally made of wood, but today they are usually made of rigid plastic or aluminum. Architect's scales may be flat, with 4 scales, or have asymmetric 3-lobed cross-section, with 6 or 12 scales.
United States and Imperial units.
In the United States, and prior to metrication in Britain, Canada and Australia, architect's scales are marked as a ratio of x inches-to-the-foot (typically written as "x"″=1′-0″). For example, one inch measured from a drawing with a scale of "one-inch-to-the-foot" is equivalent to one foot in the real world (a scale of 1:12 measured from a drawing with a scale of "two-inches-to-the-foot" is equivalent to six inches in the real world (a scale of 1:6). It is not to be confused with a true unitless ratio. A 1:5 architectural scale (inches to feet) would be a 1:60 unitless scale (inches to inches) since there are 60 inches in 5 feet.
Typical scales used in the United States are:
The following scales are generally grouped in pairs using the same dual-numbered index line (one scale is read from the right, and the other scale is read from the left):
Add History
Metric units.
Architect's scale rulers used in Britain and other metric countries are marked with ratios without reference to a base unit. Therefore, a drawing will indicate both its scale (ratio) and the unit of measurement being used.
In Britain, and elsewhere, the standard units used on architectural drawings are the (SI) units millimetres (mm) and metres (m), whereas in France centimetres (cm) and metres are most often used.
In Britain, for flat rulers, the paired scales often found on architect's scales are:
For triangular rulers, the paired scales are:
Less common scales are:
In France, in engineering departments or architectural offices, here are some scales used :
Engineer's scale.
An engineer's scale is a tool for measuring distances and transferring measurements at a fixed ratio of length. It is commonly made of plastic or aluminum and is just over long, but with the only 12  inches of markings, leaving the ends unmarked so that the first and last measuring ticks do not wear off. It is used in making engineering drawings, commonly called blueprints, blue lines, or plans on a specific scale. For example, "one-tenth size" would appear on a drawing to indicate a part larger than the drawing on the paper itself. It is not to be used to measure machined parts to see if they meet specifications.
In the United States this scale is divided into decimalized fractions of an inch but has a cross-section like an equilateral triangle, which enables the scale to have six edges indexed for measurement. One edge is divided into tenths of an inch, and the subsequent ones are directly marked for twentieths, thirtieths, fortieths, fiftieths, and finally sixtieths of an inch. Referred to as 1:10, 1:20, 1:30,1:40, 1:50 or 1:60 scale. Typically in civil engineering applications, 1:10 (1″=10′) is used exclusively for detail drawings. 1:20 and 1:40 scales are used for working plans. 1:60 is normally used only to show large areas of a project.
The engineer's scale came into existence when machining parts required a greater precision than the usual, binary fractionalization of the inch, as in the architect's scale, for houses and furniture. They were used, for example, in laying out printed circuit boards with the spacing of leads from integrated circuits as one-tenth of an inch.


53 Kalypso

Kalypso (minor planet designation: 53 Kalypso) is a large and very dark main belt asteroid that was discovered by German astronomer Robert Luther on April 4, 1858, at Düsseldorf. It is named after Calypso, a sea nymph in Greek mythology, a name it shares with Calypso, a moon of Saturn.
The orbit of 53 Kalypso places it in a mean motion resonance with the planets Jupiter and Saturn. The computed Lyapunov time for this asteroid is 19,000 years, indicating that it occupies a chaotic orbit that will change randomly over time because of gravitational perturbations of the planets.
Photometric observations of this asteroid during 2005–06 gave a light curve with a period of 18.075 ± 0.005 hours and a brightness variation of 0.14 in magnitude. In 2009, a photometric study from a different viewing angle was performed at the Organ Mesa Observatory in Las Cruces, New Mexico, yielding a rotation period of 9.036 ± 0.001 with a brightness variation of 0.14 ± 0.02 magnitude. This is exactly half of the 2005-06 result. The author of the earlier study used additional data observation that favored the 9.036 hour period. The discrepancy was deemed a consequence of viewing the asteroid from different longitudes.
Kalypso has been studied by radar.


FEAP

Florida Educator Accomplishment Practices are competencies provided by the Florida Education Standards Commission for teacher development. FEAPs are divided into three sections: Paraprofessional, Professional and Accomplished.
Paraprofessional, Professional and Accomplished FEAPs.
At all three divisions, the person performs certain activities that may take one or more of the following FEAPs: assessment, communication, continuous improvement, critical thinking, diversity, ethics, human development & learning, knowledge of subject matter, learning environments, planning, role of the teacher, and technology.


Oral Proficiency Interview

An Oral Proficiency Interview (OPI) is a standardized, global assessment of functional speaking ability. Taking the form of a conversation between the tester and test-taker, the test measures how well a person speaks a language by assessing their performance of a range of language tasks against specified criteria. In the United States, the criteria for each of ten proficiency levels are described in the ACTFL Proficiency Guidelines, devised by the American Council on the Teaching of Foreign Languages (ACTFL).
In an OPI, the test-taker is interviewed by a certified ACTFL tester, who guides the conversation to explore the abilities and limits of the individual’s oral target language abilities. During the course of the interview, the interviewee is guided to engage in a variety of tasks such as describing, narrating, and hypothesizing. The interview is recorded and scored by the interviewer as well as a second certified tester using the following scale: Superior, Advanced High, Advanced Mid, Advanced Low, Intermediate High, Intermediate Mid, Intermediate Low, Novice High, Novice Mid, Novice Low.
The OPI test format consists of four stages. In the first stage, otherwise known as the "Warm-up" stage, the interviewee is put at ease and provides the interviewer with information they can use later in the interview. The interviewer may ask "What are some things that interest you?" This stage is also used to indicate the interviewee's skill level before moving further into the interview. The second stage, called "Level Checks," helps identify what the interviewee can do and finds the highest level of sustained performance by the speaker (floor). Questions at the second stage might be,"Which cryptocurrency would you buy?" or "How is cryptocurrency changing the way we interact monetarily?" The third stage, known as "Probes" shows the interviewer what the interviewee cannot do, and finds the lowest level of performance which they are unable to sustain for prolonged periods of time (ceiling). Questions at the third stage might be, "Is Cryptocurrency a waste of money? Why or why not?" or "Explain to me why Cryptocurrency has more or less value." An effective OPI will show an interviewee what they can and can't do with their speech in the target language. The fourth and final stage, known as the "Wind-down," is designed to ease the interviewee and bring them to a comfortable level of speaking. The interviewer may end the interview by asking, "Do you have any plans for this weekend?" As the interviewer wraps up the interview, the interviewee will feel a sense of confidence as they exit the interview.
The levels of ACTFL’s scale can be conceived as an inverse triangle, with the “Superior” rating at the top representing a wide range of skill in linguistic structures, vocabulary, and fluency. The Novice Low category forms the bottom point of the triangle, showing little functional knowledge of the language. Each progressive category represents broader skills and depth of knowledge. While one can progress relatively quickly through the Novice levels, progress is much slower through the upper ratings.
OPI is generally used for native speakers of English, but it was adopted in South Korea after the computer version was developed by the Korean computer company Credu. In September 2009, 40,000 people applied to take the test in South Korea.
Oral Proficiency Interview - computer.
Oral Proficiency Interview - computer (OPIc) is a computerized test of English-usage skills developed by the American Council on the Teaching of Foreign Languages (ACTFL) and Language Testing International (LTI). It is a computer-based version of the OPI.
OPIc is a kind of test business interview. The one-hour test is a series of recorded questions which are assessed by computer. The test scores have seven levels. The evaluations are done by ACTFL professionals in the United States.
Criticism.
In addition to presenting both test takers and test users with a significant time and finciancial burden, some researchers have also noted that the ACTFL OPI is limited by the fact that its scores are based on a series of subjective statements, rather than empirical measurements of linguistic performance. Researchers have also shown that OPI test takers' ratings can be significantly affected by their anxiety during the test, and that rating judgements can vary significantly between individual raters.


Intermittent mechanism

The intermittent mechanism or intermittent movement is the device by which film is regularly advanced and then held in place for a brief duration of time in a movie camera or movie projector. This is in contrast to a continuous mechanism, whereby the film is constantly in motion and the image is held steady by optical or electronic methods. The reason the intermittent mechanism "works" for the viewer is because of a phenomenon called persistence of vision.
History.
Intermittent mechanisms were first used in sewing machines, in order for the fabric to be fed through correctly - ensuring it is stationary as each stitch is made, while moving the required distance between stitches.
Methods used.
The intermittent mechanism must be employed in concert with a rotating shutter which blocks light transmittance during the motion of the film and allows light through while the film is held in place usually by one or more registration pins. The intermittent mechanism can be accomplished in many ways, but most often, it is done with sprocket wheels, claws, or pins coupled to the camera or projector drive mechanism.
In movie theater projectors, the intermittent movement is often produced by a Geneva drive (Maltese cross mechanism).
However, in a movie camera, it is done through a process by which a shutter opens exposing the film negative to light for a split second (the standard for regular motion in North America is 1/48 of a second, which corresponds to 180 degrees, but shutters with 200 degrees were popular back when the then-available color negative film had an ASA of 50; today's color negative film is available with an ASA of 500), then the shutter closes blocking light from reaching the negative. Once the shutter is completely closed, a claw pulls down the next film frame of negative film by the sprocket holes into the film gate and the process begins again. A movie projector works in a similar way.


7 nm process

In semiconductor manufacturing, the International Technology Roadmap for Semiconductors defines the 7 nm process as the MOSFET technology node following the 10 nm node. It is based on FinFET (fin field-effect transistor) technology, a type of multi-gate MOSFET technology.
Taiwan Semiconductor Manufacturing Company (TSMC) began production of 256 Mbit SRAM memory chips using a 7 nm process in June 2016, before Samsung began mass production of 7 nm devices in 2018. The first mainstream 7 nm mobile processor intended for mass market use, the Apple A12 Bionic, was released at Apple's September 2018 event. Although Huawei announced its own 7 nm processor before the Apple A12 Bionic, the Kirin 980 on August 31, 2018, the Apple A12 Bionic was released for public, mass market use to consumers before the Kirin 980. Both chips are manufactured by TSMC.
AMD has released their "Rome" (Epyc 2) processors for servers and datacenters, which are based on TSMC's 7nm node and feature up to 64 cores and 128 threads. They have also released their "Matisse" consumer desktop processors with up to 16 cores and 32 threads. However, the I/O die on the Rome multi-chip module (MCM) is fabricated with the GloFo 14 nm process, while the Matisse's I/O die uses the GloFo 12 nm process. The Radeon RX 5000 series is also based on the N7FF process.
Since 2009, however, "node" has become a commercial name for marketing purposes that indicates new generations of process technologies, without any relation to gate length, metal pitch or gate pitch. For example, GlobalFoundries' 7 nm processes are similar to Intel's 10 nm process, thus the conventional notion of a process node has become blurred. TSMC and Samsung's 10 nm processes are somewhere between Intel's 14 nm and 10 nm processes in transistor density. The transistor density (number of transistors per square millimetre) is more important than transistor size, since smaller transistors no longer necessarily mean improved performance, or an increase in the number of transistors.
History.
Technology demos.
7 nm scale MOSFETs were first demonstrated by researchers in the early 2000s. In 2002, an IBM research team including Bruce Doris, Turkish engineer Omer Dokumaci, Taiwanese engineer Meikei Ieong and Romanian engineer Anda Mocuta fabricated a 6 nm silicon-on-insulator (SOI) MOSFET. In 2003, NEC's research team led by Hitoshi Wakabayashi and Shigeharu Yamagami fabricated a 5 nm MOSFET.
In July 2015, IBM announced that they had built the first functional transistors with 7 nm technology, using a silicon-germanium process.
In June 2016, TSMC had produced 256 Mbit SRAM memory cells at their 7 nm process, with a cell area of 0.027 square micrometres (550 F2) with reasonable risk production yields.
Expected commercialization and technologies.
In April 2016, TSMC announced that 7 nm trial production would begin in the first half of 2017. In April 2017, TSMC began risk production of 256 Mbit SRAM memory chips using a 7 nm (N7FF+) process, with extreme ultraviolet lithography (EUV). TSMC's 7 nm production plans, as of early 2017, were to use deep ultraviolet (DUV) immersion lithography initially on this process node (N7FF), and transition from risk to commercial volume manufacturing from Q2 2017 to Q2 2018. Also, their later generation 7 nm (N7FF+) production is planned to use EUV multiple patterning and to have an estimated transition from risk to volume manufacturing between 2018 and 2019.
In September 2016, GlobalFoundries announced trial production in the second half of 2017 and risk production in early 2018, with test chips already running.
In February 2017, Intel announced Fab 42 in Chandler, Arizona will produce microprocessors using 7 nm manufacturing process. The company has not published any expected values for feature lengths at this process node.
In April 2018, TSMC announced volume production of 7 nm (CLN7FF, N7) chips. In June 2018, the company announced mass production ramp up.
In May 2018, Samsung announced production of 7 nm chips this year. ASML Holding NV is their main supplier of EUV lithography machines.
In August 2018, GlobalFoundries announced it was stopping development of 7 nm chips, citing cost.
On October 28, 2018, Samsung announced their second generation 7 nm process (7LPP) had entered risk production and should enter mass production in 2019.
On January 17, 2019, for the Q4 2018 earnings call, TSMC mentioned that different customers will have "different flavors" of second generation 7 nm.
On April 16, 2019, TSMC announced their 6 nm process called (CLN6FF, N6), which is expected to be in mass products from 2021. N6 uses EUVL in up to 5 layers, compared to up to 4 layers in their N7+ process.
On July 28, 2019, TSMC announced their second gen 7 nm process called N7P, which is DUV-based like their N7 process. Since N7P is fully IP-compatible with the original 7 nm, while N7+ (which uses EUV) is not, N7+ (announced earlier as '7 nm+') is a separate process from '7 nm'. N6 ('6 nm'), another EUV-based process, is planned to be released later than even TSMC's 5 nm (N5) process, with the IP-compatibility with N7. At their Q1 2019 earnings call, TSMC reiterated their Q4 2018 statement that N7+ would generate less than $1 billion TWD in revenue in 2019.
On October 5, 2019, AMD announced their EPYC Roadmap, featuring Milan chips built using TSMC's N7+ process.
On October 7, 2019, TSMC announced they started delivering N7+ products to market in high volume.
On March 27, 2021, Intel's CEO announced that they will launch Meteor Lake processors in 2023
Technology commercialization.
In June 2018, AMD announced 7 nm Radeon Instinct GPUs launching in the second half of 2018. In August 2018, the company confirmed the release of the GPUs.
On August 21, 2018, Huawei announced their HiSilicon Kirin 980 SoC to be used in their Huawei Mate 20 and Mate 20 Pro built using TSMC's 7 nm (N7) process.
On September 12, 2018, Apple announced their A12 Bionic chip used in iPhone XS and iPhone XR built using TSMC's 7 nm (N7) process. The A12 processor became the first 7 nm chip for mass market use as it released before the Huawei Mate 20. In October 30, 2018, Apple announced their A12X Bionic chip used in iPad Pro built using TSMC's 7 nm (N7) process.
On December 4, 2018, Qualcomm announced their Snapdragon 855 and 8cx built using TSMC's 7 nm (N7) process. The first mass product featuring the Snapdragon 855 was the Lenovo Z5 Pro GT, which was announced on December 18, 2018.
On May 29, 2019, MediaTek announced their 5G SoC built using a TSMC 7 nm process.
On July 7, 2019, AMD officially launched their Ryzen 3000 series of central processing units, based on the TSMC 7 nm process and Zen 2 microarchitecture.
On August 6, 2019, Samsung announced their Exynos 9825 SoC, the first chip built using their 7LPP process. The Exynos 9825 is the first mass market chip built featuring EUVL.
On September 6, 2019, Huawei announced their HiSilicon Kirin 990 4G & 990 5G SoCs, built using TSMC's N7 and N7+ processes.
On September 10, 2019, Apple announced their A13 Bionic chip used in iPhone 11 and iPhone 11 Pro built using TSMC's 2nd gen N7P process.
7 nm manufacturing made up 36% of TSMC's revenue in the second quarter of 2020.
On August 17, 2020, IBM announced their IBM Power 10 processor.
On March 23, 2021, Intel CEO Pat Gelsinger officially announced Meteor Lake 7nm microprocessor family at Intel Unleashed: Engineering the Future webcast.
7 nm patterning difficulties.
The 7 nm foundry node is expected to utilize any of or a combination of the following patterning technologies: pitch splitting, self-aligned patterning, and EUV lithography. Each of these technologies carries significant challenges in critical dimension (CD) control as well as pattern placement, all involving neighboring features.
Pitch splitting.
Pitch splitting involves splitting features that are too close together onto different masks, which are exposed successively, followed by litho-etch processing. Due to the use of different exposures, there is always the risk of overlay error between the two exposures, as well as different CDs resulting from the different exposures.
Spacer patterning.
Spacer patterning involves depositing a layer onto pre-patterned features, then etching back to form spacers on the sidewalls of those features, referred to as core features. After removing the core features, the spacers are used as an etch mask to define trenches in the underlying layer. While the spacer CD control is generally excellent, the trench CD may fall into one of two populations, due to the two possibilities of being located where a core feature was located or in the remaining gap. This is known as 'pitch walking'. Generally pitch = core CD + gap CD + 2 * spacer CD, but this does not guarantee core CD = gap CD. For FEOL features like gate or active area isolation (e.g., fins), the trench CD is not as critical as the spacer-defined CD, in which case, spacer patterning is actually the preferred patterning approach.
When self-aligned quadruple patterning (SAQP) is used, there is a second spacer that is utilized, replacing the first one. In this case, the core CD is replaced by core CD - 2* 2nd spacer CD, and the gap CD is replaced by gap CD - 2 * 2nd spacer CD. Thus, some feature dimensions are strictly defined by the second spacer CD, while the remaining feature dimensions are defined by the core CD, core pitch, and first and second spacer CD's. The core CD and core pitch are defined by conventional lithography, while the spacer CDs are independent of lithography. This is actually expected to have less variation than pitch splitting, where an additional exposure defines its own CD, both directly and through overlay.
Spacer-defined lines also require cutting. The cut spots may shift at exposure, resulting in distorted line ends or intrusions into adjacent lines.
Self-aligned litho-etch-litho-etch (SALELE) has been implemented for 7nm BEOL patterning.
EUV lithography.
Extreme ultraviolet lithography (also known as EUV or EUVL) is capable of resolving features below 20 nm in conventional lithography style. However, the 3D reflective nature of the EUV mask results in new anomalies in the imaging. One particular nuisance is the two-bar effect, where a pair of identical bar-shaped features do not focus identically. One feature is essentially in the 'shadow' of the other. Consequently, the two features generally have different CDs which change through focus, and these features also shift position through focus. This effect may be similar to what may be encountered with pitch splitting. A related issue is the difference of best focus among features of different pitches.
EUV also has issues with reliably printing all features in a large population; some contacts may be completely missing or lines bridged. These are known as stochastic printing failures. The defect level is on the order of 1K/mm2.
The tip-to-tip gap is hard to control for EUV, largely due to the illumination constraint. A separate exposure(s) for cutting lines is preferred.
Attenuated phase shift masks have been used in production for 90 nm node for adequate focus windows for arbitrarily pitched contacts with the ArF laser wavelength (193 nm), whereas this resolution enhancement is not available for EUV.
At 2021 SPIE's EUV Lithography conference, it was reported by a TSMC customer that EUV contact yield was comparable to immersion multipatterning yield.
Comparison with previous nodes.
Due to these challenges, 7 nm poses unprecedented patterning difficulty in the back end of line (BEOL). The previous high-volume, long-lived foundry node (Samsung 10 nm, TSMC 16 nm) used pitch splitting for the tighter pitch metal layers.
Cycle time: immersion vs. EUV.
Due to the immersion tools being faster presently, multipatterning is still used on most layers. On the layers requiring immersion quad-patterning, the layer completion throughput by EUV is comparable. On the other layers, immersion would be more productive at completing the layer even with multipatterning.
7 nm process nodes and process offerings.
The naming of process nodes by different major manufacturers (TSMC, Intel, Samsung, GlobalFoundries) is partially marketing-driven and not directly related to any measurable distance on a chip for example TSMC's 7 nm node is similar in some key dimensions to Intel's 10 nm node (see transistor density, gate pitch and metal pitch in the following table). Nevertheless, as of 2017, the technological race to the greatest density was still competitive between the main players, with TSMC, Samsung, and Intel all holding leading positions between the years 2016 and 2017 when measured by the smallest feature size on chip.
Since EUV implementation at 7 nm is still limited, multipatterning still plays an important part in cost and yield; EUV adds extra considerations. The resolution for most critical layers is still determined by multiple patterning. For example, for Samsung's 7 nm, even with EUV single-patterned 36 nm pitch layers, 44 nm pitch layers would still be quadruple patterned.
GlobalFoundries' 7 nm 7LP (Leading Performance) process would have offered 40% higher performance or 60%+ lower power with a 2x scaling in density and at a 30-45+% lower cost per die over its 14 nm process. The Contacted Poly Pitch (CPP) would have been 56 nm and the Minimum Metal Pitch (MMP) would have been 40 nm, produced with Self-Aligned Double Patterning (SADP). A 6T SRAM cell would have been 0.269 square microns in size. GlobalFoundries planned to eventually use EUV lithography in an improved process called 7LP+. GlobalFoundries later stopped all 7 nm and beyond process development.
Intel has not revealed details about its 7 nm process, but its transistor density has been estimated to be around 202-250 million transistors per square millimeter. As of 2020, Intel is experiencing problems with its 7 nm process to the point of outsourcing production of its Ponte Vecchio GPUs. Intel's process has faced repeated delays, with mass production now expected in 2023.
7 nm design rule management in volume production.
The 7 nm metal patterning currently practiced by TSMC involves self-aligned double patterning (SADP) lines with cuts inserted within a cell on a separate mask as needed to reduce cell height. However, self-aligned quad patterning (SAQP) is used to form the fin, the most important factor to performance. Design rule checks also allow via multi-patterning to be avoided, and provide enough clearances for cuts that only one cut mask is needed.


Golden State Exams

The Golden State Exams (GSEs) were a family of exams that were administered to qualifying high achieving students in California during the mid 1980s through the early 2000s. The GSEs were designed based on California's curriculum framework. They were authorized in 1983 by Senate Bill 813. The first exams began being offered in 1987. Those who performed well on the exams earned one of the following awards: Recognition, Honors, or High Honors. Collectively, these awards were formally known as the Academic Excellence Awards. The exams were known for their rigorous nature. Each exam could only be taken once. The following is a timeline of when the various Golden State Exams began being offered:
There was one year (1995) when the only state testing administered in California was that to the high achieving individuals that qualified for the Golden State Exams. In 1998, high school comprehensive exams in "High School Reading/Literature" and "High School Math" became available to all students and school districts under the GSE banner. These two comprehensive exams were later integrated and absorbed into the California Standards Tests (CSTs). In 2003, the GSE subject tests were discontinued due to budget cuts.
Academic Excellence Awards.
Students who received a Recognition, Honors, or High Honors Academic Excellence Award received a certificate award and a notation on their transcript specifying the level of achievement. Those who received Honors or High Honors were additionally given gold seals on their diploma specifying the level of achievement. Results for the 1993 Chemistry Golden State Exam provide an example of the scoring distribution. Of the total population of California high school students in 1993, including 1,424,094 public high school students, only 30,429 qualified for and took the 1993 Chemistry Golden State Exam. Of those 30,429 students, 1,167 (4%) earned High Honors, 1,950 (6%) earned Honors, and 6,922 (23%) earned Recognition.


Marc Miance

²
Marc Miance (born 6 September 1976 in Meulan, France) is a film and television producer. He is the founder and CEO of Alkymia since 2010. He produced animated feature films such as "Renaissance" (2006) and "" (2015).
Biography.
Marc Miance was born in Meulan, in the suburbs of Paris. He developed an interest in computer-generated imagery (CGI) and video games at an early age. He studied at the ESRA school of cinema where he specialized in computer graphics, but dropped out after 2 years. He started to develop new techniques to create black and white CGI movies (Project BW).
In 2000, Marc Miance co-founded Attitude Studio, a production company specialized in film animations. Attitude Studio created Eve Solal, an entirely computer-generated realistic character who was intended to star in films, TV shows, and video-games. Attitude Studio innovated by developing an "emotion mapper" for the Eve Solal character, i.e. sets of body movements for each emotion triggered to make the animation less stiff, more human-like. He sold Eve Solal to the telecom company Orange for 1 billion francs the same year that it launched, in 2000. The following year, he showcased Eve Solal to ACM's Siggraph.
From 2003 to 2005, he worked on several video game animations including Eidos’ ' and Atari’s '. In 2004, inspired by Frank Miller’s "Sin City", he created the visual concept of the black-and-white sci-fi animation film "Renaissance", directed by Christian Volckman, and was in charge of the animation. Still in 2005, he co-founded the production company Let'So Ya with Isabelle Miance (spouse) and Sandrine de Sacy. Attitude Studio, now equipped with a 3,500m² motion capture studio near Paris, led a 4-million euro round of investment in 2008, and closed its operations in April 2009.
In 2010, Marc Miance became the executive producer of released in 2015 and starring Jamel Debbouze, the first European picture to be entirely filmed using motion capture. In 2010, Marc Miance also created the company Alkymia specialized in computer graphics and motion-animated technologies, a company which was instrumental to develop the technology for the movie "Animal Kingdom: Let’s Go Ape", including a 500-gram headset to capture the facial expressions of the actors.
In 2019, Miance and Indian producer Anish Mulani launched the mobile browser Popshot. In 2020, they focused the application on user privacy and renamed it Wave.


Pulses per second


Apparent temperature

Apparent temperature is the temperature equivalent perceived by humans, caused by the combined effects of air temperature, relative humidity and wind speed. The measure is most commonly applied to the perceived outdoor temperature. Apparent temperature was invented by Robert Steadman who published a paper about it in 1984. However, it also applies to indoor temperatures, especially saunas and when houses and workplaces are not sufficiently heated or cooled.
Since there is no direct measurement of solar radiation in U.S. observation systems, and solar radiation can add up to to the apparent temperature, commercial weather companies have attempted to develop their own proprietary apparent temperature systems, including The Weather Company's "FeelsLike" and AccuWeather's "RealFeel." These systems, while their exact mechanisms are trade secrets, are believed to estimate the effect of solar radiation based on the available meteorological data that is reported (such as UV index and cloud cover).


Chondrometer

A chondrometer is a measuring instrument designed to determine the bulk density of grain. Grain density is measured in kilograms per hectolitre (Imp. pounds per bushel). It is thus also referred to as the hectolitre mass.
Purpose.
Density is a guide to wheat quality and determines the price and the space required to store and transport the crop.
Description.
A chondrometer consists of a filling hopper, a measuring container, a straightedge, a weighing instrument. The filling hopper allows the grain to fall into the measuring container in a reproducible pattern as several measurements are taken, and all readings need to be within a strict degree of accuracy. The measuring cylinder has flat top edge to it can levelled using the straightedge (a strickle) to give a set volume. Today, the measuring instrument can be a set of digital scales with an accuracy greater than 0.1 g, though in the past it was a steelyard balance with the measuring cylinder hooking directly onto the scales.


Upsilon Piscium

Upsilon Piscium is a solitary, white-hued star in the zodiac constellation of Pisces. It is faintly visible to the naked eye, having an apparent visual magnitude of +4.75. Based upon an annual parallax shift of as seen from Earth, it is located about 308 light years from the Sun. The star is drifting further away with a heliocentric radial velocity of +6 km/s.
This is an ordinary A-type main sequence star with a stellar classification of A3 V. It is 461 million years old – about 98% of the way through its main sequence lifetime – and is spinning with a projected rotational velocity of 91 km/s. The star has 2.8 times the mass of the Sun, about 2.2 times the Sun's radius, and is radiating 117 times the Sun's luminosity from its photosphere at an effective temperature of 9183 K.
Naming.
υ Piscium is the Bayer designation for this star, which is Latinized as Upsilon Piscium. It has the Flamsteed designation 90 Piscium.
In Chinese, (), meaning "Legs (asterism)", refers to an asterism composed of υ Piscium, η Andromedae, 65 Piscium, ζ Andromedae, ε Andromedae, δ Andromedae, π Andromedae, ν Andromedae, μ Andromedae, β Andromedae, σ Piscium, τ Piscium, 91 Piscium, φ Piscium, χ Piscium and ψ¹ Piscium. Consequently, the Chinese name for υ Piscium itself is (, .)


Bifilar sundial

A bifilar dial is a type of sundial invented by the German mathematician Hugo Michnik in 1922. It has two non-touching threads parallel to the dial. Usually the second thread is orthogonal-(perpendicular) to the first.
The intersection of the two threads' shadows gives the local apparent time.
When the threads have the correctly calculated separation, the hour-lines on the horizontal surface are uniformly drawn. The angle between successive hour-lines is constant. The hour-lines for successive hours are 15 degrees apart.
History.
The bifilar dial was invented in April 1922 by the mathematician and maths teacher, Hugo Michnik, from Beuthen, Upper Silesia. He studied the horizontal dial- starting on a conventional XYZ cartesian framework and building up a general projection which he states was an exceptional case of a Steiner transformation. He related the trace of the sun to conic sections and the angle on the dial-plate to the hour angle and the calculation of local apparent time, using conventional hours and the historic Italian and Babylonian hours. He refers in the paper, to a previous publication on the theory of sundials in 1914.
His method has been applied to vertical near-declinant dials, and a more general declining-reclining dial.
Work has been subsequently done by Dominique Collin.
Horizontal bifilar dial.
This was the dial that Hugo Michnik invented and studied. By simplifying the general example so:
the shadow is thrown on a dial-plate marked out like a simple equatorial sundial.
The proof.
The first wire formula_2 is orientated north-south at a constant distance formula_3 from the dial plate formula_4

The second wire formula_5 is orientated east-west at a constant distance formula_6 from the dial plate formula_4 (thus formula_5 is orthogonal to formula_2 which lies on the plane of the meridian ).
In this proof formula_10 (pronounced phi) is the latitude of the dial plate.
Respectively, formula_11 and formula_12 are the vertical projections of wires formula_2 and formula_5 on the dial plate formula_4.
Point formula_16 is the point on the dial plate directly under the two wires' intersection.
 That point is the origin of the X,Y co-ordinate system referred to below.
The X-axis is the east–west line passing through the origin. The Y-axis is the north–south line passing through the origin. The positive Y direction is northward.
One can show that if the position of the sun is known and determined by the spherical coordinates formula_17 et formula_18 (pronounced t-dot and delta, respectively the known as the hour angle et declination), the co-ordinates formula_19 and formula_20 of point formula_21, the intersection on the two shadows on the dial-plate formula_4 have values of :
Eliminating the variable formula_18 in the two preceding equations, one obtains a new equation defined for formula_19 and formula_20 which gives, as a function of the latitude formula_10 and the solar hour angle solaire formula_17, the equation of the trace of the sun associated with the local apparent time. In its simplest form this equation is written:
This relation shows that the hour traces are indeed line segments and the meeting-point of these line segments is the point formula_30:
In other words, point C is south of point O (where the wires intersect), by a distance of codice_3, where formula_10 is the latitude.
If one arranges the two wire heights formula_6 and formula_3 such :
then the equation for the hour lines can be simply written as:
at all times, the intersection formula_21 of the shadows on the dial plate formula_4 is such that the angle formula_41 is equal to the hour angle formula_17 of the sun so thus represents solar time.
So provided the sundial respects the la condition formula_1 the trace of the sun corresponds to the hour-angle shown by lines (rays) centred on the point formula_30 and the 13 rays that correspond to the hours 6:00, 7:00, 8:00, 9:00... 15:00, 16:00, 17:00, 18:00 are regularly spaced at a constant angle of 15°, about point C.
A practical example.
A London dial is the name given to dials set for 51° 30' N. A simple London bifilar dial has a dial plate with 13 line segments drawn outward from a centre-point C, with each hour's line drawn 15° clockwise from the previous hour's line. The midday line is aligned towards the north.
The north–south wire is 10 cm (formula_45) above the midday line. That east-west wire is placed at a height of 7.826 (formula_46) centimeters- equivalent to 10 cm x sin(51° 30'). This passes through C. The east–west wire crosses the north–south wire 6.275 cm north of the centre-point C- that being the equivalent of - 7.826 (formula_46) divided by tan (51° 30').
Reclining-declining bifilar sundials.
Whether a sundial is a bifilar, or whether it's the familiar flat-dial with a straight style (like the usual horizontal and vertical-declining sundials), making it reclining, vertical-declining, or reclining-declining is exactly the same. The declining or reclining-declining mounting is achieved in exactly the same manner, whether the dial is bifilar, or the usual straight-style flat dial.
For any flat-dial, whether bifilar, or ordinary straight-style, the north celestial pole has a certain altitude, measured from the plane of the dial.


772 Tanete

772 Tanete is an asteroid from the asteroid belt. Since 2004 it has been observed in stellar occultation four times. Its size is best described by an ellipsoid measuring x . Analysis of a light curve captured during 2014 shows a synodic rotation period of with an amplitude of 0.15 magnitude.
In 1984, a fly-by of 772 Tanete was considered for a Mariner Mark II rendezvous mission with the short period comet 22P/Kopff.


Dual Plover

Dual Plover is a pioneering independent Australian record label, founded in Sydney in 1996, notable for discovering some of the most enigmatic artists in experimental music.
Founded by Lucas Abela and Swerve Harris, Dual Plover are concerned with releasing audio works by people whose work is outside of current trends, be it pop trends or the so-called avant-garde music trends. Dual Plover's first release 'a kombi - music to drive-by' consisted of recordings from a Volkswagen Kombi van originally recorded at picturesque Waverley Cemetery in September 1994.
From 1996 onwards they have also been manufacturing CDs and DVDs as well as touring artists such as Kevin Blechdom, Al Duval and many others, both in their native Australia as well as internationally.


Equivalent Forced Outage Rate


Sendfile

In computing, sendfile is a command which can be found in a number of contexts relating to data transmission:


Software aging

In software engineering, software aging refers to all software's tendency to fail, or cause a system failure after running continuously for a certain time, or because of ongoing changes in systems surrounding the software. Software aging has several causes, including the inability of old software to adapt to changing needs or changing technology platforms, and the tendency of software patches to introduce further errors. As the software gets older it becomes less well-suited to its purpose and will eventually stop functioning as it should. Rebooting or reinstalling the software can be seen as a short term fix. A proactive fault management method to deal with the software aging incident is software rejuvenation. This method can be classified as an environment diversity technique that usually is implemented through software rejuvenation agents (SRA).
The phenomenon was first identified by David Parnas, in an essay that explored what to do about it:
"Programs, like people, get old. We can't prevent aging, but we can understand its causes, take steps to limit its effects, temporarily reverse some of the damage it has caused, and prepare for the day when the software is no longer viable."
From both an academic and industrial point of view, the software aging phenomenon has increased. Recent research has focussed on clarifying its causes and effects. Memory bloating and leaking, along with data corruption and unreleased file-locks are particular causes of software aging.
Proactive management of software aging.
Software aging.
Software failures are a more likely cause of unplanned systems outages compared to hardware failures. This is because software exhibits over time an increasing failure rate due to data corruption, numerical error accumulation and unlimited resource consumption. In widely used and specialized software, a common action to clear a problem is rebooting because aging occurs due to the complexity of software which is never free of errors. It is almost impossible to fully verify that a piece of software is bug-free. Even high-profile software such as Windows and macOS must receive continual updates to improve performance and fix bugs. Software development tends to be driven by the need to meet release deadlines rather than to ensure long-term reliability. Designing software that can be immune to aging is difficult. Not all software will age at the same rate as some users use the system more intensively than others.
Rejuvenation.
To prevent crashes or degradation software rejuvenation can be employed proactively as inevitable aging leads to failures in software systems. This proactive technique was identified as a cost-effective solution during research at the AT&T Bell Laboratories on fault-tolerant software in the 1990s. Software rejuvenation works by removing accumulated error conditions and freeing up system resources, for example by flushing operating system kernel tables, using garbage collection, reinitializing internal data structures, and perhaps the most well known rejuvenation method is to reboot the system.
There are simple techniques and complex techniques to achieve rejuvenation. The method most individuals are familiar with is the hardware or software reboot. A more technical example would be the web server software Apache's rejuvenation method. Apache implements one form of rejuvenation by killing and recreating processes after serving a certain number of requests.
Another technique is to restart virtual machines running in a cloud computing environment.
The multinational telecommunications corporation AT&T has implemented software rejuvenation in the real time system collecting billing data in the United States for most telephone exchanges.
Some systems which have employed software rejuvenation methods include:
The IEEE International Symposium on Software Reliability Engineering (ISSRE) hosted the 5th annual International Workshop on Software Aging and Rejuvenation (woSAR) in 2013. Topics included:
Memory leaks.
In systems that use an OS user programs have to request memory blocks in order to perform an operation. After this operation (e.g. a subroutine) is completed, the program is expected to free up all the memory blocks allocated for it in order to make it available to other programs for use. In programming languages without a garbage collector (e.g. C and C++) it's up to the programmer to call the necessary memory releasing functions and to account for all the unused data within the program. However this doesn't always happen. Due to software bugs the program might consume more and more memory eventually causing the system to run out of memory. In low memory conditions, the system usually functions slower due to the performance bottleneck caused by intense swapping (thrashing), applications become unresponsive and those that request large amounts of memory unexpectedly may crash. In case the system runs out of both memory and swap even the OS might crash causing the whole system to reboot.
Programs written in programming languages that use a garbage collector (e.g. Java) usually rely on this feature for avoiding memory leaks. Thus the "aging" of these programs is at least partially dependent on the quality of the garbage collector built into the programming language's runtime environment itself.
Sometimes critical components of the OS itself can be a source of memory leaks and be the main culprit behind system stability issues. In Microsoft Windows, for example, the memory use of Windows Explorer plug-ins and long-lived processes such as services can impact the reliability of the system to the point of making it unusable. A reboot might be needed to make the system work again.
Software rejuvenation helps with memory leaks as it forces all the memory used by an application to be released. The application can be restarted but starts with a clean slate.
Implementation.
Two methods for implementing rejuvenation are:
Memory bloating.
Garbage collection is a form of automatic memory management whereby the system automatically recovers unused memory. For example, the .NET Framework manages the allocation and release of memory for software running under it. But automatically tracking these objects takes time and is not perfect.
.NET based web services manage several logical types of memory such as stack, unmanaged and managed heap (free space). As the physical memory gets full, the OS writes rarely used parts of it to disk, so that it can reallocate it to another application, a process known as paging or swapping. But if the memory does need to be used, it must be reloaded from disk. If several applications are all making large demands, the OS can spend much of its time merely moving data between main memory and disk, a process known as disk thrashing. Since the garbage collector has to examine all of the allocations to decide which are in use, it may exacerbate this thrashing. As a result, extensive swapping can lead to garbage collection cycles extended from milliseconds to tens of seconds. This results in usability problems.