Wednesday, October 2, 2013

The bestselling US novelist Tom Clancy died yesterday in a hospital in Baltimore, according to his publisher. The sixty-six year old is best known for a series of novels themed around espionage, military affairs and geopolitical intrigue, many of which have been adapted into movies and video games.

The Hunt for Red October, Clancy’s first novel, sold over five million copies and was made into a movie with Alec Baldwin and Sean Connery. President Ronald Reagan described the novel as a “perfect yarn”. The protagonist of Red October, CIA analyst Jack Ryan, starred in a series of Clancy adventures featuring wars, terrorist attacks and international political power games. Ryan has been played by Harrison Ford and later Ben Affleck.

Seventeen of his twenty novels have reached number one on the New York Times bestseller list. In 2002, Forbes magazine estimated Clancy’s earnings at US$47.8m. His final novel, Command Authority, is to be published in December.

Wednesday, October 13, 2010

The rescue of the Chilean miners trapped in the San José Mine in Copiapó, codenamed Operación San Lorenzo (San Lorenzo Operation), began on Tuesday night, at around 20:00 local time (23:00 UTC).

Florencio Ávalos was the first miner to be rescued, at 00:12 local time (03:12 UTC) on Wednesday. He was wearing a shirt signed by all his fellow miners. “The first miner is already with us. We saw it all, him hugging his wife Monica and his son Byron,” said President Piñera shortly after the first rescue. “We still have a long journey.”

“This will be recorded on every single Chilean heart forever,” Piñera added. “I hope the miners’ hope stay with us, just like the [February] earthquake victims’ [hope] and what the earthquake took off. We know that the disasters unite us all.”

All the 33 miners were rescued. The last miner, Luis Urzúa, was rescued at 21:55 Chile time (00:55 UTC). “It is a pleasure to be Chilean, [I’m] proud,” said Luis Urzúa to President Piñera. “In honour of the miners, their families, the rescuers […] let’s sing our national anthem. Viva Chile Mierda!,” said Piñera. Urzúa thanked Mining Minister Golborne and the First Lady Cecilia Morel for “fighting for their lives.” “I’m proud of my fellow miners,” Urzúa added.

Six rescuers, including a miner and a paramedic, descended to the miners’ shelter using the Fénix 3 capsule which was specially constructed for the rescue. They performed check-ups and talk with the miners before taking them back to the surface. The rescuers still don’t leave the mine.

The Fénix 3 capsules are 3.95 metres in height and weigh about 460 kilograms. They have an armour, an oxygen tube and a microphone. The occupants helmets contain an intercom to keep them in contact with the rescue team on the surface.

President of Chile Piñera assisted to the rescue. Bolivian President Evo Morales could not attend Carlos Mamani’s rescue. Mamani is the only Bolivian miner in the group.

A mass for the miners was conducted at 18:00 local time (21:00 UTC). The rescue takes between 15 and 20 minutes for each miner.

On Tuesday, Mayor of Copiapó Maglio Cicardini announced that the municipal schools in the city will have no classes this Wednesday “to transform the rescue of the Atacama’s 33 in a familiar meeting,” Radio Cooperativa reported.

“The miners will be taken to the Copiapó Regional Hospital for medical checkup, where they will have to stay for 48 hours,” Health Minister Mañalich said to Televisión Nacional de Chile.

Celebrations are taking place in several Chilean cities. In Santiago de Chile, people gathered in one of the most important points of the city, Plaza Italia. In Pichilemu, tens of cars are passing over its most important streets. In Copiapó, people gathered in its main square to assist a massive concert.

On August 5, 33 miners were trapped more than 700 meters (2,300 ft) underground, in the San José copper–gold mine, located about 40 kilometers north of Copiapó, Chile.

The youngest trapped miner is 19 years old, and the oldest is 63. There were several rescue attempts before reaching the miners’ shelter on August 22. The National Emergencies Office of Chile (ONEMI) released a list of the trapped miners on August 6, which included Franklin Lobos Ramírez, a retired footballer.

Chile is the worlds top producer of copper, according to The Economist. The San José Mine is owned by the San Esteban Mining Company (Empresa Minera San Esteban). The mine was closed down in 2007, after relatives of a miner who had died sued the company executives, but the mine was re–opened in 2008.

It was originally estimated that “it would take three to four months to complete the rescue of the trapped miners”. There were three plans to reach the miners: “Plan A” using a Strata 950 drill, “Plan B” using a Schramm T130XD drill, and “Plan C” using a RIG-422 drill. The first to reach the miners was “Plan B”, early on Saturday 9.

The last step of their rescue, announced by Health Minister Jaime Mañalich, was originally due to begin on Tuesday. Laurence Golborne, Minery Minister said “If it is possible, and the cement sets before and we don’t have any impediments to doing it, it would be wonderful,” in a press conference on Monday. The men will be extracted in a steel rescue capsule 54 cm (21 inches) in diameter.

On September 4, Chilean filmmaker Rodrigo Ortúzar announced plans to film a movie about the accident, called “Los 33” (“The 33”). The film will be released in 2011.

One miner is Bolivian, and the other 32 are Chilean.

Raúl Bustos, 40 years old, is an hydraulics engineer. He left his job in Talcahuano after the February 27 earthquake to work in the mine.

Daniel Herrera, 27 years old, is a lorry driver. He has acted as paramedic assistant in the mine. He said to La Tercera “the miners were unhappy with the psychologist in the rescue team.”

Claudio Acuña, miner, is fan of the Colo-Colo football club. The BBC reports he is aged 56, but El Comercio says he is 44.

Pedro Cortez is aged 24. He joined the mine with his friend Carlos Bugueño. Cortez is an electrician, and lost a finger in the mine a year ago.

File:Juan Aguilar with President Piñera.jpg

A native of Los Lagos, Juan Aguilar is 49 years old. Aguilar is married to Cristy Coronado, according to El Comercio. Aguilar works as a supervisor.

Mario Sepúlveda is a 39 years old electrician native of Parral; he is married. He has been the spokesman of the most of the miners’ videos. Mario Sepúlveda was the second miner to be rescued, on Wednesday at 01:10 local time (04:10 UTC).

Víctor Zamora is a 33 years old auto mechanic. Zamora is married to Jéssica Cortez, who confirmed she was pregnant while he was in the mine.

Osman Araya is 30 years old, and married. He began working as miner four months before the accident.

Florencio Ávalos is 31 years old. He is the brother of Renán Ávalos, who is also trapped in the mine. He worked as driver in San José. Ávalos filmed videos, sent later to his relatives.

Ávalos was the first miner to be rescued, on Wednesday at 00:10 local time (03:10 UTC).

Jorge Galleguillos, 56 years old, has worked all his life in the mine. He said in one video he was feeling unwell; he takes medication for hypertension.

Carlos Barrios is a 27 years old miner. His father, Antenor Barrios, told Agence France-Presse: “I find he’s very strong and has enthusiasm. He spoke loud and clear. I was excited.”

Franklin Lobos Ramírez is a 53 years old retired footballer. He played for Cobresal, Deportes Antofagasta, Club de Deportes Santiago Wanderers and Unión La Calera, and briefly for the Chile national football team. Lobos had worked as a truck driver in the mine.

Yonni Barrios, called “The Doctor”, is a 50 years old electrician. He has knowledge of first aid, and was given responsibility for monitoring the health of his colleagues. “I felt I was in hell,” Barrios said in a letter to his wife.

Carlos Bugueño, 27 years old, joined the mine with Pedro Cortez. Previously, he worked as a watchman.

Alex Vega Salazar is a 31 years old heavy machinery mechanic. He is married to Jessica Salgado, and celebrated his birthday in the mine on September 22.

Ariel Ticona is a 29 years old miner. His wife, Margarita gave birth to his daughter on September 14. She was named Esperanza (Hope), at Ticona’s request.

Richard Villarroel is a 27 years old mechanic from Coyhaique.

Edison Peña is a 34 years old miner. “I want to go out soon,” he said on his first contact with his relatives. “I want to be free, I want to see the sun,” he added. He is a fan of Elvis Presley.

Claudio Yáñez is 34 years old, and works as drill operator.

José Ojeda, 46 years old, is the master driller. Ojeda is widowed and diabetic.

Luis Urzúa is a 54 year old topographer. He is the shift-leader, and was the first miner to talk with authorities. He is known as Don Lucho among the miners. He draw plans of the area of the mine where they are trapped.

Urzúa will be the last miner to leave the mine.

José Henríquez is a 54 years old drill master. He is also an evangelical preacher, and has worked in mines for 33 years.

Víctor Segovia is a 48 years old electrician. He is in charge of writing down everything that happens in the mine.

Pablo Rojas is a 45 years old explosives loader. Married, he had been working less than six months in the mine.

Juan Illanes is a 51 year old miner. He was a sergeant in the Beagle border conflict between Chile and Argentina in 1978, the incident which almost provoked a war between the countries.

Illanes was rescued on Wednesday, at 02:07 local time (05:07 UTC).

Jimmy Sánchez, 19, is the youngest miner. He had been working in the mine for five months before the accident. His role is to check the temperature and humidity in the mine.

Samuel Ávalos is a 43 years miner. His wife Ruth said “he was addicted to the cocaine.” His role in the rescue is to check air quality in the area the miners are living. According to the BBC, “Ávalos has worked in the mine for five months.”

Mario Gómez, aged 63, is the oldest of the miners. He has worked 51 years as miner. His father was also a miner, and is nicknamed “El Navegao” (“The Sailed One”). He was thinking of retiring in November.

Gómez also wrote the message “Estamos bien en el refugio los 33” (“We are fine in the shelter the 33 [of us]”).

Segovia is 48 years old. He is married to Jessica Chille, who said “To hear his voice was a confort to my heart,” after talking with him for the first time in 24 days. His sister María, was nicknamed “La Alcaldesa” (“The Mayoress”) for her leading role at Campamento Esperanza. His father, Darío Senior, was trapped in a mine for a week, and suffered serious injuries after two other mining accidents, according to the BBC.

Carlos Mamani is a 23 years old heavy equipment operator. He is also the only non-Chilean miner; Mamani is Bolivian. He began working in the mine just five days before the accident.

He was rescued at 03:11 local time (06:11 UTC) on Wednesday.

Renán Ávalos is a 29 years old miner, single, who had been working for five months in the mine before the accident. Florencio Ávalos is his brother.

Omar Reygadas is a 56 year old electrician. He began working in the mine shortly before the accident.

Esteban Rojas is a 44 years old miner. Rojas is married to Jessica Yáñez.

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Friday, March 11, 2005Many infertile American women would choose the sex of their next child if given the option.

A survey of 561 women being treated for infertility has found that 41% would use sex selection if it were offered at no cost.

Contradicting fears that such sex selection would cause gender imbalance, the survey found that women with no children would choose baby girls and boys in approximately equal numbers.

Furthermore, women with only daughters wanted to select a male child while women with only sons wanted to select a female child.

“Sex selection is a topic that’s almost taboo for physicians to talk about,” says study lead author Tarun Jain of the University of Illinois at Chicago. “Prior to this study, there has been no data to indicate what the demand might be.”

Of 561 survey respondents, 229 would want to select the sex of their future child.

Among these, 45% had no children and 48% had children of all the same sex.

Half would choose to select the sex of their next child even if they had to bear the cost.

About 55% would choose sperm separation, 41% would choose preimplantation genetic diagnosis and 4% would choose neither.

Sex selection is controversial. The American College of Obstetricians and Gynecologists opposes it for nonmedical reasons and so does the International Federation of Gynecology and Obstetrics.

The American Society of Reproductive Medicine supports it for nonmedical reasons for family gender balancing provided methods used are safe and effective.

“As the techniques gain more popularity, physicians will have to decide if they will offer the procedure to patients with and without children,” says Jain.

The research is reported in the journal Fertility and Sterility.

Monday, September 20, 2010

Leonard Skinner, the namesake of rock band Lynyrd Skynyrd, has died at the age of 77. Skinner was a gym teacher and basketball coach and taught members of the group. His death was announced by his son, also named Leonard Skinner, who also said that he was suffering from Alzheimer’s disease.

Skinner died at the St. Catherine Laboure Manor nursing home in Riverside at 02.30 a.m. His son said that he had a bowl of ice cream shortly after midnight. He had been at the home for about a year.

The coach taught the members of the group in the 1960s and was reportedly hard on the students. He later said in a 2009 interview that “he was just following the rules”. He disputed the rumours that he was extra tough on them or that he kicked them out of school.

In later years he opened up his own bar and became friends with some members of the group and even introduced them at one of their concerts in Jacksonville.

Monday, December 11, 2006

On December 7, BBC News reported a story about Dr James Anderson, a teacher in the Computer Science department at the University of Reading in the United Kingdom. In the report it was stated that Anderson had “solved a very important problem” that was 1200 years old, the problem of division by zero. According to the BBC, Anderson had created a new number, that he had named “nullity”, that lay outside of the real number line. Anderson terms this number a “transreal number”, and denotes it with the Greek letter ? {\displaystyle \Phi } . He had taught this number to pupils at Highdown School, in Emmer Green, Reading.

The BBC report provoked many reactions from mathematicians and others.

In reaction to the story, Mark C. Chu-Carroll, a computer scientist and researcher, posted a web log entry describing Anderson as an “idiot math teacher”, and describing the BBC’s story as “absolutely infuriating” and a story that “does an excellent job of demonstrating what total innumerate idiots reporters are”. Chu-Carroll stated that there was, in fact, no actual problem to be solved in the first place. “There is no number that meaningfully expresses the concept of what it means to divide by zero.”, he wrote, stating that all that Anderson had done was “assign a name to the concept of ‘not a number'”, something which was “not new” in that the IEEE floating-point standard, which describes how computers represent floating-point numbers, had included a concept of “not a number”, termed “NaN“, since 1985. Chu-Carroll further continued:

“Basically, he’s defined a non-solution to a non-problem. And by teaching it to his students, he’s doing them a great disservice. They’re going to leave his class believing that he’s a great genius who’s solved a supposed fundamental problem of math, and believing in this silly nullity thing as a valid mathematical concept.

“It’s not like there isn’t already enough stuff in basic math for kids to learn; there’s no excuse for taking advantage of a passive audience to shove this nonsense down their throats as an exercise in self-aggrandizement.

“To make matters worse, this idiot is a computer science professor! No one who’s studied CS should be able to get away with believing that re-inventing the concept of NaN is something noteworthy or profound; and no one who’s studied CS should think that defining meaningless values can somehow magically make invalid computations produce meaningful results. I’m ashamed for my field.”

There have been a wide range of other reactions from other people to the BBC news story. Comments range from the humorous and the ironic, such as the B1FF-style observation that “DIVIDION^[sic] BY ZERO IS IMPOSSIBLE BECAUSE MY CALCULATOR SAYS SO AND IT IS THE TRUTH” and the Chuck Norris Fact that “Only Chuck Norris can divide by zero.” (to which another reader replied “Chuck Norris just looks at zero, and it divides itself.”); through vigourous defences of Dr Anderson, with several people quoting the lyrics to Ira Gershwin‘s song “They All Laughed (At Christopher Columbus)”; to detailed mathematical discussions of Anderson’s proposed axioms of transfinite numbers.

Several readers have commented that they consider this to have damaged the reputation of the Computer Science department, and even the reputation of the University of Reading as a whole. “By publishing his childish nonsense the BBC actively harms the reputation of Reading University.” wrote one reader. “Looking forward to seeing Reading University maths application plummit.” wrote another. “Ignore all research papers from the University of Reading.” wrote a third. “I’m not sure why you refer to Reading as a ‘university’. This is a place the BBC reports as closing down its physics department because it’s too hard. Lecturers at Reading should stick to folk dancing and knitting, leaving academic subjects to grown ups.” wrote a fourth. Steve Kramarsky lamented that Dr Anderson is not from the “University of ‘Rithmetic“.

Several readers criticised the journalists at the BBC who ran the story for not apparently contacting any mathematicians about Dr Anderson’s idea. “Journalists are meant to check facts, not just accept whatever they are told by a self-interested third party and publish it without question.” wrote one reader on the BBC’s web site. However, on Slashdot another reader countered “The report is from Berkshire local news. Berkshire! Do you really expect a local news team to have a maths specialist? Finding a newsworthy story in Berkshire probably isn’t that easy, so local journalists have to cover any piece of fluff that comes up. Your attitude to the journalist should be sympathy, not scorn.”

Ben Goldacre, author of the Bad Science column in The Guardian, wrote on his web log that “what is odd is a reporter, editor, producer, newsroom, team, cameraman, soundman, TV channel, web editor, web copy writer, and so on, all thinking it’s a good idea to cover a brilliant new scientific breakthrough whilst clearly knowing nothing about the context. Maths isn’t that hard, you could even make a call to a mathematician about it.”, continuing that “it’s all very well for the BBC to think they’re being balanced and clever getting Dr Anderson back in to answer queries about his theory on Tuesday, but that rather skips the issue, and shines the spotlight quite unfairly on him (he looks like a very alright bloke to me).”.

From reading comments on his own web log as well as elsewhere, Goldacre concluded that he thought that “a lot of people might feel it’s reporter Ben Moore, and the rest of his doubtless extensive team, the people who drove the story, who we’d want to see answering the questions from the mathematicians.”.

Andrej Bauer, a professional mathematician from Slovenia writing on the Bad Science web log, stated that “whoever reported on this failed to call a university professor to check whether it was really new. Any university professor would have told this reporter that there are many ways of dealing with division by zero, and that Mr. Anderson’s was just one of known ones.”

Ollie Williams, one of the BBC Radio Berkshire reporters who wrote the BBC story, initially stated that “It seems odd to me that his theory would get as far as television if it’s so easily blown out of the water by visitors to our site, so there must be something more to it.” and directly responded to criticisms of BBC journalism on several points on his web log.

He pointed out that people should remember that his target audience was local people in Berkshire with no mathematical knowledge, and that he was “not writing for a global audience of mathematicians”. “Some people have had a go at Dr Anderson for using simplified terminology too,” he continued, “but he knows we’re playing to a mainstream audience, and at the time we filmed him, he was showing his theory to a class of schoolchildren. Those circumstances were never going to breed an in-depth half-hour scientific discussion, and none of our regular readers would want that.”.

On the matter of fact checking, he replied that “if you only want us to report scientific news once it’s appeared, peer-reviewed, in a recognised journal, it’s going to be very dry, and it probably won’t be news.”, adding that “It’s not for the BBC to become a journal of mathematics — that’s the job of journals of mathematics. It’s for the BBC to provide lively science reporting that engages and involves people. And if you look at the original page, you’ll find a list as long as your arm of engaged and involved people.”.

Williams pointed out that “We did not present Dr Anderson’s theory as gospel, although with hindsight it could have been made clearer that this is very much a theory and by no means universally accepted. But we certainly weren’t shouting a mathematical revolution from the rooftops. Dr Anderson has, in one or two places, been chastised for coming to the media with his theory instead of his peers — a sure sign of a quack, boffin and/or crank according to one blogger. Actually, one of our reporters happened to meet him during a demonstration against the closure of the university’s physics department a couple of weeks ago, got chatting, and discovered Dr Anderson reckoned he was onto something. He certainly didn’t break the door down looking for media coverage.”.

Some commentators, at the BBC web page and at Slashdot, have attempted serious mathematical descriptions of what Anderson has done, and subjected it to analysis. One description was that Anderson has taken the field of real numbers and given it complete closure so that all six of the common arithmetic operators were surjective functions, resulting in “an object which is barely a commutative ring (with operators with tons of funky corner cases)” and no actual gain “in terms of new theorems or strong relation statements from the extra axioms he has to tack on”.

Jamie Sawyer, a mathematics undergraduate at the University of Warwick writing in the Warwick Maths Society discussion forum, describes what Anderson has done as deciding that R ? { ? ? , + ? } {\displaystyle \mathbb {R} \cup \lbrace -\infty ,+\infty \rbrace } , the so-called extended real number line, is “not good enough […] because of the wonderful issue of what 0 0 {\displaystyle {\frac {0}{0}}} is equal to” and therefore creating a number system R ? { ? ? , ? , + ? } {\displaystyle \mathbb {R} \cup \lbrace -\infty ,\Phi ,+\infty \rbrace } .

Andrej Bauer stated that Anderson’s axioms of transreal arithmetic “are far from being original. First, you can adjoin + ? {\displaystyle +\infty } and ? ? {\displaystyle -\infty } to obtain something called the extended real line. Then you can adjoin a bottom element to represent an undefined value. This is all standard and quite old. In fact, it is well known in domain theory, which deals with how to represent things we compute with, that adjoining just bottom to the reals is not a good idea. It is better to adjoin many so-called partial elements, which denote approximations to reals. Bottom is then just the trivial approximation which means something like ‘any real’ or ‘undefined real’.”

Commentators have pointed out that in the field of mathematical analysis, 0 0 {\displaystyle {\frac {0}{0}}} (which Anderson has defined axiomatically to be ? {\displaystyle \Phi } ) is the limit of several functions, each of which tends to a different value at its limit:

• lim x ? 0 x 0 {\displaystyle \lim _{x\to 0}{\frac {x}{0}}} has two different limits, depending from whether x {\displaystyle x} approaches zero from a positive or from a negative direction.
• lim x ? 0 0 x {\displaystyle \lim _{x\to 0}{\frac {0}{x}}} also has two different limits. (This is the argument that commentators gave. In fact, 0 x {\displaystyle {\frac {0}{x}}} has the value 0 {\displaystyle 0} for all x ? 0 {\displaystyle x\neq 0} , and thus only one limit. It is simply discontinuous for x = 0 {\displaystyle x=0} . However, that limit is different to the two limits for lim x ? 0 x 0 {\displaystyle \lim _{x\to 0}{\frac {x}{0}}} , supporting the commentators’ main point that the values of the various limits are all different.)
• Whilst sin ? 0 = 0 {\displaystyle \sin 0=0} , the limit lim x ? 0 sin ? x x {\displaystyle \lim _{x\to 0}{\frac {\sin x}{x}}} can be shown to be 1, by expanding the sine function as an infinite Taylor series, dividing the series by x {\displaystyle x} , and then taking the limit of the result, which is 1.
• Whilst 1 ? cos ? 0 = 0 {\displaystyle 1-\cos 0=0} , the limit lim x ? 0 1 ? cos ? x x {\displaystyle \lim _{x\to 0}{\frac {1-\cos x}{x}}} can be shown to be 0, by expanding the cosine function as an infinite Taylor series, dividing the series subtracted from 1 by x {\displaystyle x} , and then taking the limit of the result, which is 0.

Commentators have also noted l’Hôpital’s rule.

It has been pointed out that Anderson’s set of transreal numbers is not, unlike the set of real numbers, a mathematical field. Simon Tatham, author of PuTTY, stated that Anderson’s system “doesn’t even think about the field axioms: addition is no longer invertible, multiplication isn’t invertible on nullity or infinity (or zero, but that’s expected!). So if you’re working in the transreals or transrationals, you can’t do simple algebraic transformations such as cancelling x {\displaystyle x} and ? x {\displaystyle -x} when both occur in the same expression, because that transformation becomes invalid if x {\displaystyle x} is nullity or infinity. So even the simplest exercises of ordinary algebra spew off a constant stream of ‘unless x is nullity’ special cases which you have to deal with separately — in much the same way that the occasional division spews off an ‘unless x is zero’ special case, only much more often.”

Tatham stated that “It’s telling that this monstrosity has been dreamed up by a computer scientist: persistent error indicators and universal absorbing states can often be good computer science, but he’s stepped way outside his field of competence if he thinks that that also makes them good maths.”, continuing that Anderson has “also totally missed the point when he tries to compute things like 0 0 {\displaystyle 0^{0}} using his arithmetic. The reason why things like that are generally considered to be ill-defined is not because of a lack of facile ‘proofs’ showing them to have one value or another; it’s because of a surfeit of such ‘proofs’ all of which disagree! Adding another one does not (as he appears to believe) solve any problem at all.” (In other words: 0 0 {\displaystyle 0^{0}} is what is known in mathematical analysis as an indeterminate form.)

To many observers, it appears that Anderson has done nothing more than re-invent the idea of “NaN“, a special value that computers have been using in floating-point calculations to represent undefined results for over two decades. In the various international standards for computing, including the IEEE floating-point standard and IBM’s standard for decimal arithmetic, a division of any non-zero number by zero results in one of two special infinity values, “+Inf” or “-Inf”, the sign of the infinity determined by the signs of the two operands (Negative zero exists in floating-point representations.); and a division of zero by zero results in NaN.

Anderson himself denies that he has re-invented NaN, and in fact claims that there are problems with NaN that are not shared by nullity. According to Anderson, “mathematical arithmetic is sociologically invalid” and IEEE floating-point arithmetic, with NaN, is also faulty. In one of his papers on a “perspex machine” dealing with “The Axioms of Transreal Arithmetic” (Jamie Sawyer writes that he has “worries about something which appears to be named after a plastic” — “Perspex” being a trade name for polymethyl methacrylate in the U.K..) Anderson writes:

We cannot accept an arithmetic in which a number is not equal to itself (NaN != NaN), or in which there are three kinds of numbers: plain numbers, silent numbers, and signalling numbers; because, on writing such a number down, in daily discourse, we can not always distinguish which kind of number it is and, even if we adopt some notational convention to make the distinction clear, we cannot know how the signalling numbers are to be used in the absence of having the whole program and computer that computed them available. So whilst IEEE floating-point arithmetic is an improvement on real arithmetic, in so far as it is total, not partial, both arithmetics are invalid models of arithmetic.

In fact, the standard convention for distinguishing the two types of NaNs when writing them down can be seen in ISO/IEC 10967, another international standard for how computers deal with numbers, which uses “qNaN” for non-signalling (“quiet”) NaNs and “sNaN” for signalling NaNs. Anderson continues:

[NaN’s] semantics are not defined, except by a long list of special cases in the IEEE standard.

“In other words,” writes Scott Lamb, a BSc. in Computer Science from the University of Idaho, “they are defined, but he doesn’t like the definition.”.

The main difference between nullity and NaN, according to both Anderson and commentators, is that nullity compares equal to nullity, whereas NaN does not compare equal to NaN. Commentators have pointed out that in very short order this difference leads to contradictory results. They stated that it requires only a few lines of proof, for example, to demonstrate that in Anderson’s system of “transreal arithmetic” both 1 = 2 {\displaystyle 1=2} and 1 ? 2 {\displaystyle 1\neq 2} , after which, in one commentator’s words, one can “prove anything that you like”. In aiming to provide a complete system of arithmetic, by adding extra axioms defining the results of the division of zero by zero and of the consequent operations on that result, half as many again as the number of axioms of real-number arithmetic, Anderson has produced a self-contradictory system of arithmetic, in accordance with Gödel’s incompleteness theorems.

One reader-submitted comment appended to the BBC news article read “Step 1. Create solution 2. Create problem 3. PROFIT!”, an allusion to the business plan employed by the underpants gnomes of the comedy television series South Park. In fact, Anderson does plan to profit from nullity, having registered on the 27th of July, 2006 a private limited company named Transreal Computing Ltd, whose mission statement is “to develop hardware and software to bring you fast and safe computation that does not fail on division by zero” and to “promote education and training in transreal computing”. The company is currently “in the research and development phase prior to trading in hardware and software”.

In a presentation given to potential investors in his company at the ANGLE plc showcase on the 28th of November, 2006, held at the University of Reading, Anderson stated his aims for the company as being:

• To build a transreal computer.
• To derive Maxwell’s equations and classical gravitation in transreal numbers so that they have no naked singularities (infinities affecting a neighbourhood of space).
• To collaborate with anyone who wants to unify Quantum Electro-Dynamics with gravitation.

To investors, Anderson makes the following promises:

• “I will help you develop a curriculum for transreal arithmetic if you want me to.”
• “I will help you unify QED and gravitation if you want me to.”
• “I will build a transreal supercomputer.”

He asks potential investors:

• “How much would you pay to know that the engine in your ship, car, aeroplane, or heart pacemaker won’t just stop dead?”
• “How much would you pay to know that your Government’s computer controlled military hardware won’t just stop or misfire?”

The current models of computer arithmetic are, in fact, already designed to allow programmers to write programs that will continue in the event of a division by zero. The IEEE’s Frequently Asked Questions document for the floating-point standard gives this reply to the question “Why doesn’t division by zero (or overflow, or underflow) stop the program or trigger an error?”:

“The [IEEE] 754 model encourages robust programs. It is intended not only for numerical analysts but also for spreadsheet users, database systems, or even coffee pots. The propagation rules for NaNs and infinities allow inconsequential exceptions to vanish. Similarly, gradual underflow maintains error properties over a precision’s range.

“When exceptional situations need attention, they can be examined immediately via traps or at a convenient time via status flags. Traps can be used to stop a program, but unrecoverable situations are extremely rare. Simply stopping a program is not an option for embedded systems or network agents. More often, traps log diagnostic information or substitute valid results.”

Simon Tatham stated that there is a basic problem with Anderson’s ideas, and thus with the idea of building a transreal supercomputer: “It’s a category error. The Anderson transrationals and transreals are theoretical algebraic structures, capable of representing arbitrarily big and arbitrarily precise numbers. So the question of their error-propagation semantics is totally meaningless: you don’t use them for down-and-dirty error-prone real computation, you use them for proving theorems. If you want to use this sort of thing in a computer, you have to think up some concrete representation of Anderson transfoos in bits and bytes, which will (if only by the limits of available memory) be unable to encompass the entire range of the structure. And the point at which you make this transition from theoretical abstract algebra to concrete bits and bytes is precisely where you should also be putting in error handling, because it’s where errors start to become possible. We define our theoretical algebraic structures to obey lots of axioms (like the field axioms, and total ordering) which make it possible to reason about them efficiently in the proving of theorems. We define our practical number representations in a computer to make it easy to detect errors. The Anderson transfoos are a consequence of fundamentally confusing the one with the other, and that by itself ought to be sufficient reason to hurl them aside with great force.”

Geomerics, a start-up company specializing in simulation software for physics and lighting and funded by ANGLE plc, had been asked to look into Anderson’s work by an unnamed client. Rich Wareham, a Senior Research and Development Engineer at Geomerics and a MEng. from the University of Cambridge, stated that Anderson’s system “might be a more interesting set of axioms for dealing with arithmetic exceptions but it isn’t the first attempt at just defining away the problem. Indeed it doesn’t fundamentally change anything. The reason computer programs crash when they divide by zero is not that the hardware can produce no result, merely that the programmer has not dealt with NaNs as they propagate through. Not dealing with nullities will similarly lead to program crashes.”

“Do the Anderson transrational semantics give any advantage over the IEEE ones?”, Wareham asked, answering “Well one assumes they have been thought out to be useful in themselves rather than to just propagate errors but I’m not sure that seeing a nullity pop out of your code would lead you to do anything other than what would happen if a NaN or Inf popped out, namely signal an error.”.

Sunday, November 25, 2007

Despite the hopes of many University of Wisconsin-Madison (UW) students, The Onion was not named after their student center. “People always ask questions about where the name The Onion came from,” said President Sean Mills in an interview with David Shankbone, “and when I recently asked Tim Keck, who was one of the founders, he told me the name—I’ve never heard this story about ‘see you at the un-yun’—he said it was literally that his Uncle said he should call it The Onion when he saw him and Chris Johnson eating an onion sandwich. They had literally just cut up the onion and put it on bread.” According to Editorial Manager Chet Clem, their food budget was so low when they started the paper that they were down to white bread and onions.

Long before The Daily Show and The Colbert Report, Heck and Johnson envisioned a publication that would parody the news—and news reporting—when they were students at UW in 1988. Since its inception, The Onion has become a veritable news parody empire, with a print edition, a website that drew 5,000,000 unique visitors in the month of October, personal ads, a 24 hour news network, podcasts, and a recently launched world atlas called Our Dumb World. Al Gore and General Tommy Franks casually rattle off their favorite headlines (Gore’s was when The Onion reported he and Tipper were having the best sex of their lives after his 2000 Electoral College defeat). Many of their writers have gone on to wield great influence on Jon Stewart and Stephen Colbert‘s news parody shows.

And we are sorry to break the news to all you amateur headline writers: your submissions do not even get read.

Below is David Shankbone’s interview with Chet Clem and Sean Mills about the news empire that has become The Onion.

See the discussion page for instructions on adding schools to this list.Tuesday, September 13, 2005

NAICU has created a list of colleges and universities accepting and/or offering assistance to displace faculty members. [1]Wednesday, September 7, 2005

This list is taken from Colleges offering admission to displaced New Orleans students, and is intended to make searching easier for faculty, graduate, and professional students.

In addition to the list below, the Association of American Law Schools has compiled a list of law schools offering assistance to displaced students. [2] As conditions vary by college, interested parties should contact the Office of Admissions at the school in question for specific requirements and up-to-date details.

The Association of American Medical Colleges is coordinating alternatives for medical students and residents displaced by Hurricane Katrina. [3]

ResCross.net is acting as a central interactive hub for establishing research support in times of emergency. With so many scientists affected by Hurricane Katrina, ResCross is currently focused on providing information to identify sources of emergency support as quickly as possible. [4]

With so many scientists affected by Hurricane Katrina, ResCross is currently focused on providing information to identify sources of emergency support as quickly as possible.

Physics undergraduates, grad students, faculty and high school teachers can be matched up with housing and jobs at universities, schools and industry. [5] From the American Association of Physics Teachers, the Society of Physics Students, the American Institute of Physics and the American Physical Society.

If you are seeking or providing assistance, please use this site to find information on research support, available lab space/supplies, resources, guidelines and most importantly to communicate with fellow researchers.

The following is a partial list, sorted by location.

Alabama |Alaska |Arizona |Arkansas |California |Colorado |Connecticut |Delaware |District of Columbia |Florida |Georgia |Hawaii |Idaho |Illinois |Indiana |Iowa |Kansas |Kentucky |Louisiana |Maine |Maryland |Massachusetts |Michigan |Minnesota |Mississippi |Missouri |Montana |Nebraska |Nevada |New Hampshire |New Jersey |New Mexico |New York |North Carolina |North Dakota |Ohio |Oklahoma |Oregon |Pennsylvania |Rhode Island |South Carolina |South Dakota |Tennessee |Texas |Utah |Vermont |Virginia |Washington |West Virginia |Wisconsin |Wyoming |Canada