Monday, November 20, 2017

First Known Interstellar Asteroid

ʻOumuamua (formally designated 1I; previously C/2017 U1 (PANSTARRS) and A/2017 U1) is an apparent interstellar object passing through the Solar System. It was discovered on a highly hyperbolic orbit by Robert Weryk on October 19, 2017 with observations made by the Pan-STARRS telescope when the object was 0.2 AU (30,000,000 km; 19,000,000 mi) from Earth. Initially thought to be a comet, it was reclassified as an asteroid a week later. It is the first of a new class called hyperbolic asteroids.

Based on a 29-day observation arc, ʻOumuamua's orbital eccentricity is 1.20, the highest of any object yet observed in the Solar System. The previous record holder was C/1980 E1 with an outbound-orbit eccentricity of 1.057. The high eccentricity of ʻOumuamua both inbound and outbound indicates that it has never been gravitationally bound to the Solar System and is presumably an interstellar object due to its high incoming velocity. It has an inclination of 123° with respect to the ecliptic, and had a speed of 26.32 km/s (58,900 mph) relative to the sun when in interstellar space, which peaked at 87.71 km/s at perihelion


This is the first known example of an interstellar object, appearing to come from roughly the direction of the star Vega in the constellation Lyra, with a hyperbolic excess velocity of 26 km/s with respect to the Sun. This direction is close to the Solar apex, the most likely direction for approaches from objects outside the Solar System. But it is unknown how long the object has been drifting among the stars in the galactic disc. The Solar System is likely the first star system that ʻOumuamua has closely encountered since being ejected from its birth star system potentially several billion years ago.

On October 26, 2017, two precovery observations from the Catalina Sky Survey were found dated October 14 and October 17. A two-week observation arc has verified the strongly hyperbolic nature of this object. Observations and conclusions on the composition, shape, behavior and origin compiled from the Very Large Telescope in Chile were collected by Weyrk and colleagues and published in Nature on 20 November, as ʻOumuamua was on its escape trajectory from the solar system.

Assuming it is a rock with an albedo of 10%, it would be approximately 160 meters (500 ft) in diameter. Spectra recorded by the 4.2-meter William Herschel Telescope on October 25 showed that the object was featureless, colored red like Kuiper belt objects. Spectra from the Hale Telescope showed a less red color resembling comet nuclei or Trojans. Its spectrum is similar to that of D-type or P-type asteroids.

1I/ʻOumuamua has a rotation period of 8.1 hours, with a lightcurve amplitude of 1.8 mag. This indicates that it is a highly elongated object with an axis ratio of at least 5.3:1, comparable to the most elongated Solar System objects. According to astronomer David Jewitt, the object is physically unremarkable except for its highly elongated shape. Assuming an albedo of 0.1 (typical for D-type asteroids), 1I/ʻOumuamua has dimensions of approximately 180 × 30 × 30 meters. Bannister, et al. have suggested that it could also be a contact binary.

Extrapolating the orbit backwards, the asteroid is calculated to have gone through perihelion on September 9, 2017 and to have passed approximately 0.1616 AU (24,180,000 km; 15,020,000 ) from Earth on October 14, 2017. The object is small and faint, and by the end of October had already faded to apparent magnitude ~23.

It has been speculated that the object may have been ejected from a stellar system in the Carina-Columba association some 45 million years ago. The Carina-Columba stellar association is now very far in the sky from the constellation Lyra, the direction from which the object came. About 1.3 million years ago the object may have passed the nearby star TYC4742-1027-1 within a distance of 0.16 parsecs (0.52 light-years), but its velocity is too high to have originated from this star as it probably just passed through the Oort cloud of that system at a speed of 103 km/s.

One hundred years ago, the object was 7002561000000000000♠561±0.6 AU (84 billion km) from the Sun and traveling at 26 km/s with respect to the Sun. The object continued to speed up until it went through perihelion, where it peaked at 87.7 km/s. By the discovery date it had slowed down to 46 km/s and will continue to slow down until it reaches a speed of 26 km/s relative to the Sun. This interstellar speed is within ~5 km/s of other stars within the Sun's stellar neighborhood, which also indicates an interstellar origin. The object will ultimately head away from the Sun at an angle of 66° from the direction it came from. As it leaves the Solar System, it will be around R.A. 23h51m and declination +24°45', in Pegasus.


Sunday, November 19, 2017

Mary Wollstonecraft Shelley

Mary Wollstonecraft Shelley (née Godwin; 30 August 1797 – 1 February 1851) was an English novelist, short story writer, dramatist, essayist, biographer, and travel writer, best known for her Gothic novel Frankenstein: or, The Modern Prometheus (1818). She also edited and promoted the works of her husband, the Romantic poet and philosopher Percy Bysshe Shelley. Her father was the political philosopher William Godwin, and her mother was the philosopher and feminist Mary Wollstonecraft.

                                              Mary Shelley -- portrait by Richard Rothwell

After Wollstonecraft's death less than a month after her daughter Mary was born, Mary was raised by Godwin, who was able to provide his daughter with a rich, if informal, education, encouraging her to adhere to his own liberal political theories. When Mary was four, her father married a neighbour, with whom, as her stepmother, Mary came to have a troubled relationship.

In 1814, Mary began a romance with one of her father's political followers, Percy Bysshe Shelley, who was already married. Together with Mary's stepsister Claire Clairmont, Mary and Shelley left for France and travelled through Europe. Upon their return to England, Mary was pregnant with Percy's child. Over the next two years, she and Percy faced ostracism, constant debt, and the death of their prematurely born daughter. They married in late 1816, after the suicide of Percy Shelley's first wife, Harriet.

In 1816, the couple famously spent a summer with Lord Byron, John William Polidori, and Claire Clairmont near Geneva, Switzerland, where Mary conceived the idea for her novel Frankenstein. The Shelleys left Britain in 1818 for Italy, where their second and third children died before Mary Shelley gave birth to her last and only surviving child, Percy Florence Shelley. In 1822, her husband drowned when his sailing boat sank during a storm near Viareggio. A year later, Mary Shelley returned to England and from then on devoted herself to the upbringing of her son and a career as a professional author. The last decade of her life was dogged by illness, probably caused by the brain tumour that was to kill her at the age of 53.

Until the 1970s, Mary Shelley was known mainly for her efforts to publish her husband's works and for her novel Frankenstein, which remains widely read and has inspired many theatrical and film adaptations. Recent scholarship has yielded a more comprehensive view of Mary Shelley’s achievements. Scholars have shown increasing interest in her literary output, particularly in her novels, which include the historical novels Valperga (1823) and Perkin Warbeck (1830), the apocalyptic novel The Last Man (1826), and her final two novels, Lodore (1835) and Falkner (1837). Studies of her lesser-known works, such as the travel book Rambles in Germany and Italy (1844) and the biographical articles for Dionysius Lardner's Cabinet Cyclopaedia (1829–46), support the growing view that Mary Shelley remained a political radical throughout her life. Mary Shelley's works often argue that cooperation and sympathy, particularly as practised by women in the family, were the ways to reform civil society. This view was a direct challenge to the individualistic Romantic ethos promoted by Percy Shelley and the Enlightenment political theories articulated by her father, William Godwin.


Saturday, November 18, 2017

Robert Mugabe Arrested after Coup

Robert Gabriel Mugabe (born 21 February 1924) is a Zimbabwean revolutionary and politician who has been President of Zimbabwe since 1987. His current status is a matter of dispute following a recent coup d'etat. He previously led Zimbabwe as Prime Minister from 1980 to 1987. He chaired the Zimbabwe African National Union (ZANU) group from 1975 to 1980, and has led its successor political party, the ZANU – Patriotic Front (ZANU–PF), since 1980. Ideologically an African nationalist, during the 1970s and 1980s he identified as a Marxist-Leninist although after the 1990s self-identified only as a socialist; his policies have been described as Mugabeism.

Mugabe was born to a poor Shona family in Kutama, Southern Rhodesia. Following an education at Kutama College and the University of Fort Hare, he worked as a school teacher in Southern Rhodesia, Northern Rhodesia, and Ghana. Angered that Southern Rhodesia was a British colony governed by a white minority, Mugabe embraced Marxism and joined African nationalist protests calling for an independent black-led state. After making anti-government comments he was convicted of sedition and imprisoned between 1964 and 1974. On release he fled to Mozambique, established his leadership of ZANU, and oversaw ZANU's role in the Rhodesian Bush War, fighting Ian Smith's predominantly white government. He reluctantly took part in the peace negotiations brokered by the United Kingdom that resulted in the Lancaster House Agreement. The agreement dismantled white minority rule and resulted in the 1980 general election, at which Mugabe led ZANU-PF to victory and became Prime Minister of the newly renamed Zimbabwe. Mugabe's administration expanded healthcare and education, and—despite his Marxist rhetoric and professed desire for a socialist society—adhered largely to conservative economic policies.

Mugabe's initial calls for racial reconciliation failed to stem deteriorating race relations and growing white flight. Relations with Joshua Nkomo's Zimbabwe African People's Union (ZAPU) also declined, with Mugabe crushing ZAPU-linked opposition in Matabeleland during the Gukurahundi between 1982 and 1985; at least 10,000 people, mostly Ndebele civilians, were killed by Mugabe's Fifth Brigade. Pursuing decolonization, Mugabe's government emphasised the redistribution of land controlled by white farmers to landless blacks, initially on a "willing seller-willing buyer" basis. Frustrated at the slow rate of redistribution, from 2000 Mugabe encouraged the violent seizure of white-owned land. Food production was severely impacted, generating famine, international sanctions, and drastic economic decline. Opposition to Mugabe grew, particularly through the Movement for Democratic Change, although he was re-elected in 2002, 2008, and 2013 through campaigns dominated by violence, electoral fraud, and nationalistic appeals to his rural Shona voter base. Internationally, Mugabe sent troops to fight in the Second Congo War and chaired the Non-Aligned Movement (1986–89), the Organisation of African Unity (1997–98), and the African Union (2015–16). On November 15, 2017, he was placed under house arrest as Zimbabwe's military took control in a coup.

Having dominated Zimbabwe's politics for nearly four decades, Mugabe has been a controversial and divisive figure. He has been praised as a revolutionary hero of the African liberation struggle who helped to free Zimbabwe from British colonialism, imperialism, and white minority rule. Conversely, he has been derided as a dictator responsible for economic mismanagement, widespread corruption, anti-white racial discrimination, human rights abuses, suppression of political critics, and crimes against humanity.


Friday, November 17, 2017

Good Luck Charms

Good luck charm is a charm that is believed to bring good luck. An example of this is a blessing that a minister or a priest gives at the end of a ceremony. Later on, people assumed that spoken words were temporary whereas a solid object is more permanent. Objects that have extraordinary significance such as the splinter believed to be from the cross of Jesus Christ were substituted for the original spoken or sung charms.

Almost any object can be used as a charm. Coins and buttons are good examples. Little things that are given to you make very good lucky charms. It is because of the favorable associations they make. Many souvenir shops have a range of tiny items that may be used as good luck charms. Good luck charms are usually worn on the body although there are exceptions


The “lucky rabbit charm” was passed on and incorporated into American culture by African slaves that were brought to the Americas. The lucky bag or the “Mojo” is another borrowed idea from African culture. It is used in voodoo ceremonies to carry several lucky objects or spells and intended to cause a specific effect. The concept is that particular objects placed in the bag and charged will create a supernatural effect for the bearer. Even today, mojo bags are still used. Europe also contributed to the concept of lucky charms. Adherents of St. Patrick (the patron saint of Ireland), adopted the Four leaf clover as a symbol of Irish luck because clovers are abundant in the hills of Ireland.

A four-leaf clover was consistently believed to be a lucky charm. This very old Irish verse describes why:

One leaf is for fame,
And one leaf is for wealth,
And one is for a faithful lover,
And one to bring you glorious health,
Are all in the four-leaved clover

Afterword by the Blog Author

There are many other charms which are used for confidence games.  One televangelist sold “lucky coins” that were guaranteed to bring good luck to those in the television audience smart enough to acquire them.

Charm bracelets are magnets for spending money on small tourist items at gift shops.  Much of this market is centered around pompous sentimentality.

There is a popular sugary American breakfast cereal called Lucky Charms for which the kibbles of cereal are shaped like charm bracelet objects.

Think of charms as baby amulets or miniature talismans.

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

An amulet is an object that is typically worn on one's person, and is alleged to have the magical power to protect its holder– either to protect them in general or to protect them from some specific thing. Amulets are different from talismans because are sometimes confused a talisman may have alleged magical powers other than protection. Amulets with pendants– small aesthetic objects that hang from necklaces. Any given pendant may indeed be an amulet, but so may any other object which purports to protect its holder from danger.

Potential amulets include gems, especially engraved gems, statues, coins, drawings, pendants, rings, plant parts, animal parts, and even written words in the form of a magical spell or incantation to repel evil or bad luck. Magic scrolls are found to be used in various cultures, and artifacts of scrolls with magical inscriptions have been found in the middle east, Europe, and the far east.

The word "amulet" comes from the Latin word amulētum. The earliest extant use of that term is in Pliny's Natural History, in which it means "an object that protects a person from trouble".

Thursday, November 16, 2017

Pluto's Chilling Haze

Pluto's Hydrocarbon Haze Keeps
Dwarf Planet Colder than Expected
New analysis of Pluto's atmosphere explains why New Horizons
spacecraft measured temperatures much colder than predicted
By Tim Stephens, UC Santa Cruz

November 15, 2017 -- The gas composition of a planet's atmosphere generally determines how much heat gets trapped in the atmosphere. For the dwarf planet Pluto, however, the predicted temperature based on the composition of its atmosphere was much higher than actual measurements taken by NASA's New Horizons spacecraft in 2015.

A new study published November 16 in Nature proposes a novel cooling mechanism controlled by haze particles to account for Pluto's frigid atmosphere.

"It's been a mystery since we first got the temperature data from New Horizons," said first author Xi Zhang, assistant professor of Earth and planetary sciences at UC Santa Cruz. "Pluto is the first planetary body we know of where the atmospheric energy budget is dominated by solid-phase haze particles instead of by gases."

The cooling mechanism involves the absorption of heat by the haze particles, which then emit infrared radiation, cooling the atmosphere by radiating energy into space. The result is an atmospheric temperature of about 70 Kelvin (minus 203 degrees Celsius, or minus 333 degrees Fahrenheit), instead of the predicted 100 Kelvin (minus 173 Celsius, or minus 280 degrees Fahrenheit).

According to Zhang, the excess infrared radiation from haze particles in Pluto's atmosphere should be detectable by the James Webb Space Telescope, allowing confirmation of his team's hypothesis after the telescope's planned launch in 2019.

Extensive layers of atmospheric haze can be seen in images of Pluto taken by New Horizons. The haze results from chemical reactions in the upper atmosphere, where ultraviolet radiation from the sun ionizes nitrogen and methane, which react to form tiny hydrocarbon particles tens of nanometers in diameter. As these tiny particles sink down through the atmosphere, they stick together to form aggregates that grow larger as they descend, eventually settling onto the surface.

"We believe these hydrocarbon particles are related to the reddish and brownish stuff seen in images of Pluto's surface," Zhang said.

The researchers are interested in studying the effects of haze particles on the atmospheric energy balance of other planetary bodies, such as Neptune's moon Triton and Saturn's moon Titan. Their findings may also be relevant to investigations of exoplanets with hazy atmospheres.

Zhang's coauthors are Darrell Strobel, a planetary scientist at Johns Hopkins University and co-investigator on the New Horizons mission, and Hiroshi Imanaka, a scientist at NASA Ames Research Center in Mountain View, who studies the chemistry of haze particles in planetary atmospheres. This research was funded by NASA.

Wednesday, November 15, 2017

Hitler's Etiquette Tutor

Helene Bechstein née Capito (26 May 1876 – 20 April 1951) was a German socialite and businesswoman. She was an etiquette tutor for Adolf Hitler and was the wife of Edwin Bechstein, the owner and later majority shareholder of C. Bechstein, a leading manufacturer of pianos.


Helene Capito was born in Düsseldorf in 1876. Helene married Edwin Bechstein . In 1923, following C. Bechstein becoming a limited company, Helene and Carl started buying the majority of shares with Helene speaking in public on the company's behalf. At numerous events, she is heard making antisemitic comments, which led to a number of high-profile musicians boycotting C. Bechstein pianos. In 1934, the company was restructured so that Helene became the majority shareholder. To help raise capital, she sold company property to Hermann Göring through his capacity as Minister President of Prussia.

Tutoring Hitler

Bechstein first met Adolf Hitler in 1921 through Dietrich Eckart at her Berchtesgaden Villa. She took a liking to him and when he was imprisoned after the failed Beer Hall Putsch, she would regularly visit him in prison and once claimed to the prison that he was her adopted son. Upon Hitler's release, Bechstein introduced him to German high society in Berlin. Along with Elsa Bruckmann and Winifred Wagner, she helped to teach Hitler table manners and helped reform his public image. Both Bechstein and Hitler grew close to each other, with Bechstein giving Hitler gifts including a RM26,000 Mercedes and calling him "Wolfchen", stating she would have liked to have had him as a son. Hitler reciprocated by allegedly giving her an original manuscript to Mein Kampf. The Bechsteins both publicly funded Hitler, giving him the funds to continue publishing Völkischer Beobachter.

When the Nazis came to power in 1934, Hitler awarded her the Golden Party Badge. Bechstein herself did not join the Nazi Party until 1944. Bechstein had hoped that Hitler would marry her daughter.

After the War

After Nazi Germany's surrender in the Second World War, C. Bechstein was commandeered by the Allies in the US Occupation Zone and Bechstein's shares were confiscated by the Americans. The company was not permitted to start making pianos again until 1948. Bechstein herself was sentenced to 60 days hard labour and had 30% of her assets stripped from her for being a Nazi collaborator. She died in 1951.


Tuesday, November 14, 2017

Power Pop Rock with Examples

Power pop is a pop rock music subgenre that draws its inspiration from 1960s British and American rock music. It typically incorporates a combination of musical devices including strong melodies, clear vocals, economical arrangements and prominent guitar riffs. Instrumental solos are usually kept to a minimum, and blues elements are largely downplayed.

In the 1980s and 1990s, Power Pop continued as a commercially modest genre but by the mid-1990s through the 2000s, power pop was mainly in the underground.

While its cultural impact has waxed and waned over the decades, power pop is among rock's most enduring subgenres.

Characteristics of Pop Rock

The origins of power pop date back to the early-to-mid 1960's with what AllMusic calls: "a cross between the crunching hard rock of the Who and the sweet melodicism of the Beatles and the Beach Boys, with the ringing guitars of the Byrds thrown in for good measure". According to The Rolling Stone Encyclopedia of Rock & Roll, the sub-genre's key influences came from British Invasion bands, particularly the Merseybeat sound first popularised by the Beatles and its "jangly guitars, pleasant melodies, immaculate vocal harmonies, and a general air of teenage innocence".

It was Pete Townshend, of the English rock band the Who, that coined the term "power pop" in a 1967 interview in which he said: "Power pop is what we play—what the Small Faces used to play, and the kind of pop the Beach Boys played in the days of 'Fun, Fun, Fun' which I preferred." The Small Faces are often cited as being among the progenitors of power pop. The Who's role in the creation of power pop has been cited by singer-songwriter Eric Carmen of the Raspberries, who has said:

Pete Townshend coined the phrase to define what the Who did. For some reason, it didn't stick to the Who, but it did stick to these groups that came out in the '70s that played kind of melodic songs with crunchy guitars and some wild drumming. It just kind of stuck to us like glue, and that was okay with us because the Who were among our highest role models. We absolutely loved the Who.

Several other groups of the 1960s were important in the evolution and expansion of the power pop style, such as the Hollies and the Monkees, as well as "softer" acts such as the Beau Brummels, the Cowsills and the Zombies. Other acts such as the Knickerbockers, the Easybeats and the Outsiders contributed iconic singles. Writer John Borack has noted, "It's also quite easy to draw a not-so-crooked line from garage rock to power pop."[

Although the formative influences on the genre were primarily British, the bands that developed and codified power pop in the 1970s were nearly all American. The Raspberries' 1972 hit single "Go All The Way" is an almost perfect embodiment of the elements of power pop and that group's four albums can be considered strongly representative of the genre.

Afterword by the Blog Author

Power Pop got going with the British Invasion of the mid-1960s.  My own ears seem to gravitate toward “I Can See for Miles and Miles” by the Who as well as the stereo version of Paul McCartney’s “Here, There and Everywhere.”  The definitive power pop tunes are probably “No Matter What” by Badfinger and the Raspberries’ “Go All the Way.”

The best of the Beatles out of their own after the 1970 breakup has a lot of Power Pop in the studio work and arrangements.  “It Don’t Come Easy” by Ringo Starr is a fine example of this kind of work, and Ringo does some heavy drumming with help from his friend George Harrison advising on the production.  It therefore seems to me that the defining elements of Power Pop are a large element of percussion, the re-introduction of the piano and often the trumpet as short solo rock instruments, simple lyrics sung perfectly on-key, and a flippant, “life goes on” attitude about unrequited love.  So here is a list of what may be the top examples of Power Pop:

·         I Can See for Miles and Miles – the Who

·         Listen to What the Man Said – Paul McCartney

·         When We Was Fab – George Harrison

·         Isn’t It Time – The Babys

·         Rockin’ at Midnight – The Honeydrippers

·         Go All the Way – Raspberries

·         Day after Day – Badfinger

·         No Matter What – Badfinger

·         It Don’t Come Easy – Ringo Starr

·         Live and Let Die – Paul and Linda McCartney

·         Free as a Bird – The Beatles

·         Here, There, and Everywhere (in stereo) – The Beatles

·         Rock On – David Essex

·         Then Came You – The Spinners with Dionne Warwick

·         Smoke on the Water – Deep Purple

·         Crackerbox Palace – George Harrison

·         Oh Sherrie – Steve Perry

·         Wake Me Up Before You Go-Go – Wham!

·         Feeling Good – George Michael and Wham!

·         Still the One – Orleans

·         Brandy – Looking Glass

·         We Will Rock You -- Queen

Monday, November 13, 2017

Physics: The Elusive Tetraquark

A tetraquark, in particle physics, is an exotic meson composed of four valence quarks. In principle, a tetraquark state may be allowed in quantum chromodynamics, the modern theory of strong interactions. Any established tetraquark state would be an example of an exotic hadron which lies outside the quark model classification.

In 2003 a particle temporarily called X(3872), by the Belle experiment in Japan, was proposed to be a tetraquark candidate, as originally theorized. The name X is a temporary name, indicating that there are still some questions about its properties to be tested. The number following is the mass of the particle in MeV/c2.

In 2004, the DsJ(2632) state seen in Fermilab's SELEX was suggested as a possible tetraquark candidate.

In 2007, Belle announced the observation of the Z(4430) state, a ccdu tetraquark candidate. There are also indications that the Y(4660), also discovered by Belle in 2007, could be a tetraquark state.

In 2009, Fermilab announced that they have discovered a particle temporarily called Y(4140), which may also be a tetraquark.

In 2010, two physicists from DESY and a physicist from Quaid-i-Azam University re-analyzed former experimental data and announced that, in connection with the
ϒ(5S) meson (a form of bottomonium), a well-defined tetraquark resonance exists.

In June 2013, the BES III experiment in China and the Belle experiment in Japan independently reported on Zc(3900), the first confirmed four-quark state.

In 2014, the Large Hadron Collider experiment LHCb confirmed the existence of the Z(4430) state with a significance of over 13.9 σ.

In February 2016, the DØ experiment announced the observation of a narrow tetraquark candidate, named X(5568), decaying to Bsπ±. However, preliminary results from LHCb, presented at the 51st Rencontres de Moriond Electroweak session, show no evidence for the state, despite a much larger sample of B0sπ± candidates.

In June 2016, LHCb announced the discovery of three additional tetraquark candidates, called X(4274), X(4500) and X(4700).



See also this Newsweek article on recent work:

Sunday, November 12, 2017

Basics of Dietary Fiber

Dietary fiber or roughage is the indigestible portion of food derived from plants. It has two main components:

  • Soluble fiber, which dissolves in water, is readily fermented in the colon into gases and physiologically active byproducts, and can be prebiotic and viscous. It delays gastric emptying which in turn can cause an extended feeling of fullness.
  • Insoluble fiber, which does not dissolve in water, is metabolically inert and provides bulking, or it can be prebiotic and metabolically ferment in the large intestine. Bulking fibers absorb water as they move through the digestive system, easing defecation.

Dietary fibers can act by changing the nature of the contents of the gastrointestinal tract and by changing how other nutrients and chemicals are absorbed. Some types of soluble fiber absorb water to become a gelatinous, viscous substance which is fermented by bacteria in the digestive tract. Some types of insoluble fiber have bulking action and are not fermented. Lignin, a major dietary insoluble fiber source, may alter the rate and metabolism of soluble fibers. Other types of insoluble fiber, notably resistant starch, are fully fermented. Some but not all soluble plant fibers block intestinal mucosal adherence and translocation of potentially pathogenic bacteria and may therefore modulate intestinal inflammation, an effect that has been termed contrabiotic.

Chemically, dietary fiber consists of non-starch polysaccharides such as arabinoxylans, cellulose, and many other plant components such as resistant starch, resistant dextrins, inulin, lignin, chitins, pectins, beta-glucans, and oligosaccharides. A novel position has been adopted by the US Department of Agriculture to include functional fibers as isolated fiber sources that may be included in the diet. The term "fiber" is something of a misnomer, since many types of so-called dietary fiber are not actually fibrous.

Food sources of dietary fiber are often divided according to whether they provide (predominantly) soluble or insoluble fiber. Plant foods contain both types of fiber in varying degrees, according to the plant's characteristics.

Advantages of consuming fiber are the production of healthful compounds during the fermentation of soluble fiber, and insoluble fiber's ability (via its passive hygroscopic properties) to increase bulk, soften stool, and shorten transit time through the intestinal tract. A disadvantage of a diet high in fiber is the potential for significant intestinal gas production and bloating.

Definition of Dietary Fiber

Originally, fiber was defined to be the components of plants that resist human digestive enzymes, a definition that includes lignin and polysaccharides. The definition was later changed to also include resistant starch, along with inulin and other oligosaccharides.

Sources of Fiber

Plant sources of fiber

Some plants contain significant amounts of soluble and insoluble fiber. For example, plums and prunes have a thick skin covering a juicy pulp. The skin is a source of insoluble fiber, whereas soluble fiber is in the pulp. Grapes also contain a fair amount of fiber.

The root of the konjac plant, or glucomannan, produces results similar to fiber and may also be used to relieve constipation. Glucomannan is sold in various forms, and while safe in some forms, it can be unsafe in others, possibly leading to throat or intestinal blockage.

Soluble fiber is found in varying quantities in all plant foods, including:

  • legumes (peas, soybeans, lupins and other beans)
  • oats, rye, chia, and barley
  • some fruits (including figs, avocados, plums, prunes, berries, ripe bananas, and the skin of apples, quinces and pears)
  • certain vegetables such as broccoli, carrots, and Jerusalem artichokes
  • root tubers and root vegetables such as sweet potatoes and onions (skins of these are sources of insoluble fiber also)
  • psyllium seed husks (a mucilage soluble fiber) and flax seeds
  • nuts, with almonds being the highest in dietary fiber

Sources of insoluble fiber include:

  • whole grain foods
  • wheat and corn bran
  • legumes such as beans and peas
  • nuts and seeds
  • potato skins
  • lignans
  • vegetables such as green beans, cauliflower, zucchini (courgette), celery, and nopal
  • some fruits including avocado, and unripe bananas
  • the skins of some fruits, including kiwifruit, grapes and tomatoes

Dietary Fiber and Obesity

Dietary fiber has many functions in diet, one of which may be to aid in energy intake control and reduced risk for development of obesity. The role of dietary fiber in energy intake regulation and obesity development is related to its unique physical and chemical properties that aid in early signals of satiation and enhanced or prolonged signals of satiety. Early signals of satiation may be induced through cephalic- and gastric-phase responses related to the bulking effects of dietary fiber on energy density and palatability, whereas the viscosity-producing effects of certain fibers may enhance satiety through intestinal-phase events related to modified gastrointestinal function and subsequent delay in fat absorption. In general, fiber-rich diets, whether achieved through fiber supplementation or incorporation of high fiber foods into meals, have a reduced energy density compared with high fat diets. This is related to fiber’s ability to add bulk and weight to the diet. There are also indications that women may be more sensitive to dietary manipulation with fiber than men. The relationship of body weight status and fiber effect on energy intake suggests that obese individuals may be more likely to reduce food intake with dietary fiber inclusion.

Guidelines for Fiber Intake

Current recommendations from the United States National Academy of Sciences, Institute of Medicine, state that for Adequate Intake, adult men ages 14–50 consume 38 grams of dietary fiber per day, men 51 and older 30 grams, women ages 19–50 to consume 25 grams per day, women 51 and older 21 grams.

The AND (Academy of Nutrition and Dietetics, previously ADA) recommends a minimum of 20–35 g/day for a healthy adult depending on calorie intake (e.g., a 2000 Cal/8400 kJ diet should include 25 g of fiber per day). The AND's recommendation for children is that intake should equal age in years plus 5 g/day (e.g., a 4 year old should consume 9 g/day). No guidelines have yet been established for the elderly or very ill. Patients with current constipation, vomiting, and abdominal pain should see a physician. Certain bulking agents are not commonly recommended with the prescription of opioids because the slow transit time mixed with larger stools may lead to severe constipation, pain, or obstruction.

The British Nutrition Foundation has recommended a minimum fiber intake of 18 g/day for healthy adults.


Saturday, November 11, 2017

"Technical Debt" in Programming

Technical debt (also known as design debt or code debt) is a concept in software development that reflects the implied cost of additional rework caused by choosing an easy solution now instead of using a better approach that would take longer.

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

As a change is started on a codebase, there is often the need to make other coordinated changes at the same time in other parts of the codebase or documentation. Required changes that are not completed are considered debt that must be paid at some point in the future. Just like financial debt, these uncompleted changes incur interest on top of interest, making it cumbersome to build a project. Although the term is used in software development primarily, it can also be applied to other professions.


Common causes of technical debt include (a combination of):

  • Insufficient up-front definition, where requirements are still being defined during development, development starts before any design takes place. This is done to save time but often has to be reworked later.
  • Business pressures, where the business considers getting something released sooner before all of the necessary changes are complete, builds up technical debt comprising those uncompleted changes.
  • Lack of process or understanding, where businesses are blind to the concept of technical debt, and make decisions without considering the implications.
  • Tightly-coupled components, where functions are not modular, the software is not flexible enough to adapt to changes in business needs.
  • Lack of a test suite, which encourages quick and risky band-aids to fix bugs.
  • Lack of documentation, where code is created without necessary supporting documentation. The work to create any supporting documentation represents a debt that must be paid.
  • Lack of collaboration, where knowledge isn't shared around the organization and business efficiency suffers, or junior developers are not properly mentored.
  • Parallel development on two or more branches accrues technical debt because of the work required to merge the changes into a single source base. The more changes that are done in isolation, the more debt is piled up.
  • Delayed refactoring – As the requirements for a project evolve, it may become clear that parts of the code have become inefficient or difficult to edit and must be refactored in order to support future requirements. The longer that refactoring is delayed, and the more code is added, the bigger the debt.
  • Lack of alignment to standards, where industry standard features, frameworks, technologies are ignored. Eventually, integration with standards will come, doing sooner will cost less (similar to 'delayed refactoring').
  • Lack of knowledge, when the developer simply doesn't know how to write elegant code.
  • Lack of ownership, when outsourced software efforts result in in-house engineering being required to refactor or rewrite outsourced code.
  • Poor technological leadership where poorly thought out commands handed down the chain of command increases the technical debt rather than reduce it.
  • Last minute specification changes; these have potential to percolate throughout a project but no time or budget to see them through with documentation and checks.

Consequences of Technical Debt

"Interest payments" are caused by both the necessary local maintenance and the absence of maintenance by other users of the project. Ongoing development in the upstream project can increase the cost of "paying off the debt" in the future. One pays off the debt by simply completing the uncompleted work.

The buildup of technical debt is a major cause for projects to miss deadlines. It is difficult to estimate exactly how much work is necessary to pay off the debt. For each change that is initiated, an uncertain amount of uncompleted work is committed to the project. The deadline is missed when the project realizes that there is more uncompleted work (debt) than there is time to complete it in. To have predictable release schedules, a development team should limit the amount of work in progress in order to keep the amount of uncompleted work (or debt) small at all times.

If enough work is completed on a project to not present a barrier to submission, then a project will be released which still carries a substantial amount of technical debt. If this software reaches production, then the risks of implementing any future refactors which might address the technical debt increase dramatically. Modifying production code carries the risk of outages, actual financial losses and possibly legal repercussions if contracts involve service-level agreements (SLA). For this reason we can view the carrying of technical debt to production almost as if it were an increase in interest rate and the only time this decreases is when deployments are turned down and retired.

"As an evolving program is continually changed, its complexity, reflecting deteriorating structure, increases unless work is done to maintain or reduce it."

— Meir Manny Lehman, 1980

While Manny Lehman's Law already indicated that evolving programs continually add to their complexity and deteriorating structure unless work is done to maintain them, Ward Cunningham first drew the comparison between technical complexity and debt in a 1992 experience report:

"Shipping first time code is like going into debt. A little debt speeds development so long as it is paid back promptly with a rewrite... The danger occurs when the debt is not repaid. Every minute spent on not-quite-right code counts as interest on that debt. Entire engineering organizations can be brought to a stand-still under the debt load of an unconsolidated implementation, object-oriented or otherwise."

— Ward Cunningham, 1992

In his 2004 text, Refactoring to Patterns, Joshua Kerievsky presents a comparable argument concerning the costs associated with architectural negligence, which he describes as "design debt".

Activities that might be postponed include documentation, writing tests, attending to TODO comments and tackling compiler and static code analysis warnings. Other instances of technical debt include knowledge that isn't shared around the organization and code that is too confusing to be modified easily.

Grady Booch compares how evolving cities is similar to evolving software-intensive systems and how lack of refactoring can lead to technical debt.

"The concept of technical debt is central to understanding the forces that weigh upon systems, for it often explains where, how, and why a system is stressed. In cities, repairs on infrastructure are often delayed and incremental changes are made rather than bold ones. So it is again in software-intensive systems. Users suffer the consequences of capricious complexity, delayed improvements, and insufficient incremental change; the developers who evolve such systems suffer the slings and arrows of never being able to write quality code because they are always trying to catch up."

— Grady Booch, 2014

In open source software, postponing sending local changes to the upstream project is a technical debt.

Related Topics

  • Code smell (symptoms of inferior code quality that can contribute to technical debt)
  • Big ball of mud
  • Software rot
  • Bus factor
  • Escalation of commitment
  • Software entropy
  • Sunk costs


Friday, November 10, 2017

Financial Stress Leads to Heart Attack

Significant Financial Stress Associated with
13-fold higher Odds of Having a Heart Attack

Johannesburg, South Africa – Nov 9, 2017 -- Significant financial stress is associated with a 13-fold higher odds of having a heart attack, according to research presented at the 18th Annual Congress of the South African Heart Association.

The SA Heart Congress 2017 is being held from 9 to 12 November in Johannesburg. Experts from the European Society of Cardiology (ESC) will present a special programme.

“The role of psychosocial factors in causing disease is a neglected area of study in South Africa, perhaps because there are so many other pressing health challenges such as tuberculosis and HIV,” said lead author Dr Denishan Govender, associate lecturer, University of the Witwatersrand, Johannesburg.

“The INTERHEART study showed that psychosocial factors are independently associated with acute myocardial infarction (heart attack) in Africa but as far as we are aware there are no other published local data,” said last author Professor Pravin Manga, professor of cardiology, University of the Witwatersrand.

This study included 106 patients with acute myocardial infarction who presented to a large public hospital in Johannesburg. A control group of 106 patients without cardiac disease was matched for age, sex and race. All participants completed a questionnaire about depression, anxiety, stress, work stress, and financial stress in the previous month. The Likert scale was used to grade the experience of each condition.

Regarding financial stress, patients were graded with no financial stress if they were coping financially; mild financial stress if they were coping financially but needed added support; moderate financial stress if they had an income but were in financial distress; and significant financial stress if they had no income and at times struggled to meet basic needs.

Levels of psychosocial conditions were compared between groups and used to calculate associations with having a heart attack.

Self-reported stress levels were common, with 96% of heart attack patients reporting any level of stress, and 40% reporting severe stress levels. There was a three-fold increased risk of myocardial infarction if a patient had experienced any level of depression (from mild to extremely severe) in the previous month compared to those with no depression.

Both work stress and financial stress were associated with a higher risk of acute myocardial infarction. The odds of myocardial infarction was 5.6 times higher in patients with moderate or severe work stress compared to those with minimal or no stress. Patients with significant financial stress had a 13-fold higher odds of having a myocardial infarction.

Dr Govender said: “Our study suggests that psychosocial aspects are important risk factors for acute myocardial infarction. Often patients are counselled about stress after a heart attack but there needs to be more emphasis prior to an event. Few doctors ask about stress, depression or anxiety during a general physical and this should become routine practice, like asking about smoking. Just as we provide advice on how to quit smoking, patients need information on how to fight stress.”

Professor Manga said: “There is growing recognition that many developing countries are experiencing an increasing prevalence of chronic diseases of lifestyle such as myocardial infarction, and South Africa is no exception. Our study shows that psychosocial aspects are an area of cardiovascular prevention that deserves more attention.”

Dr David Jankelow, Chairman of the SA Heart 2017 Congress, commented: “We know that the depressed cardiac patient is at greater risk. We as clinicians need to identify them much earlier, so that they can be referred for appropriate intervention. Cardiac rehabilitation together with counselling and reassurance will play an important role as well.”

Professor Fausto Pinto, ESC immediate past president and course director of the ESC programme in South Africa, said: “Psychosocial factors including stress at work, depression and anxiety contribute to the risk of developing cardiovascular disease and having a worse prognosis. European prevention guidelines say that psychosocial risk factor assessment should be considered in people with, or at high risk of, cardiovascular disease to identify possible barriers to lifestyle change or adherence to medication.”


Thursday, November 9, 2017

Does Exercise Alleviate Depression?

Should Exercise Be What the
Doctor Orders for Depression?
More mental health providers may want to take a closer look at including exercise in their patients’ treatment plans, a new study suggests.

Michigan State University and University of Michigan researchers asked 295 patients receiving treatment at a mental health clinic whether they wanted to be more physically active and if exercise helped improve their mood and anxiety. They also asked if patients wanted their therapist to help them become more active.

Eighty-five percent said they wanted to exercise more and over 80 percent believed exercise helped improve their moods and anxiety much of the time. Almost half expressed interest in a one-time discussion, with many participants also wanting ongoing advice about physical activity with their mental health provider.

The study is now published in the journal General Hospital Psychiatry.

“Physical activity has been shown to be effective in alleviating mild to moderate depression and anxiety,” said Carol Janney, lead author of the study and an MSU assistant professor of epidemiology. “Current physical activity guidelines advise at least 30 minutes, five days a week to promote mental and physical health, yet many of those surveyed weren’t meeting these recommendations.”

More than half of the participants said their mood limited their ability to exercise, which Janney said provides an opportunity for physicians and therapists in clinics to offer additional support.

“Offering physical activity programs inside the mental health clinics may be one of many patient-centered approaches that can improve the mental and physical health of patients,” Janney said.

Marcia Valenstein, senior author and professor emeritus in psychiatry at U-M, agreed.

“Mental health treatment programs need to partner with fitness programs to support their patients’ willingness to exercise more,” she said. “This support might come from integrating personal trainers into mental health clinics or having strong partnerships with the YMCA or other community recreational facilities.”

Both Valenstein and Janney said that psychiatrists and other providers might discuss with patients the general need to exercise, but few actually sit down with patients and create a comprehensive exercise plan for them or regularly make sure they are adhering to a specific goal.

“Mental health providers such as psychiatrists and therapists may not have the necessary training to prescribe physical activity as part of their mental health practice,” Janney said. “But by teaming up with certified personal trainers or other exercise programs, it may help them prescribe or offer more recommendations for physical activity in the clinic setting.”

Results also showed that over half of the patients surveyed showed interest in getting help from a personal trainer and were willing to pay a bit extra, but that the topic of physical activity was rarely discussed by their physician.

“This is a missed opportunity,” Valenstein said. “If we can make it easier for both therapists and their patients to have easier access to physical activity services, then we are likely to help more patients reduce their depression and anxiety.”

Once the effectiveness of this approach is proven, she added, health insurers might consider moving in the direction of covering services that help people exercise.

“Several insurers already do this for diabetes prevention, so it’s not out of the question.”