lunes, febrero 26, 2007

A reminder of the sophistication of art, architecture and science long ago

In the beauty and geometric complexity of tile mosaics on walls of medieval Islamic buildings, scientists have recognized patterns suggesting that the designers had made a conceptual breakthrough in mathematics beginning as early as the 13th century.

Science

A piece from a mausoleum in Turkey.

W. B. Denny

A pattern taken from a Turkish mosque.

A new study shows that the Islamic pattern-making process, far more intricate than the laying of one’s bathroom floor, appears to have involved an advanced math of quasi crystals, which was not understood by modern scientists until three decades ago.

The findings, reported in the current issue of the journal Science, are a reminder of the sophistication of art, architecture and science long ago in the Islamic culture. They also challenge the assumption that the designers somehow created these elaborate patterns with only a ruler and a compass. Instead, experts say, they may have had other tools and concepts.

Two years ago, Peter J. Lu, a doctoral student in physics at Harvard University, was transfixed by the geometric pattern on a wall in Uzbekistan. It reminded him of what mathematicians call quasi-crystalline designs. These were demonstrated in the early 1970s by Roger Penrose, a mathematician and cosmologist at the University of Oxford.

Mr. Lu set about examining pictures of other tile mosaics from Afghanistan, Iran, Iraq and Turkey, working with Paul J. Steinhardt, a Princeton cosmologist who is an authority on quasi crystals and had been Mr. Lu’s undergraduate adviser. The research was a bit like trying to figure out the design principle of a jigsaw puzzle, Mr. Lu said in an interview.

In their journal report, Mr. Lu and Dr. Steinhardt concluded that by the 15th century, Islamic designers and artisans had developed techniques “to construct nearly perfect quasi-crystalline Penrose patterns, five centuries before discovery in the West.”

Some of the most complex patterns, called “girih” in Persian, consist of sets of contiguous polygons fitted together with little distortion and no gaps. Running through each polygon (a decagon, pentagon, diamond, bowtie or hexagon) is a decorative line. Mr. Lu found that the interlocking tiles were arranged in predictable ways to create a pattern that never repeats — that is, quasi crystals.

“Again and again, girih tiles provide logical explanations for complicated designs,” Mr. Lu said in a news release from Harvard.

He and Dr. Steinhardt recognized that the artisans in the 13th century had begun creating mosaic patterns in this way. The geometric star-and-polygon girihs, as quasi crystals, can be rotated a certain number of degrees, say one-fifth of a circle, to positions from which other tiles are fitted. As such, this makes possible a pattern that is infinitely big and yet the pattern never repeats itself, unlike the tiles on the typical floor.

This was, the scientists wrote, “an important breakthrough in Islamic mathematics and design.”

Dr. Steinhardt said in an interview that it was not clear how well the Islamic designers understood all the elements they were applying to the construction of these patterns. “I can just say what’s on the walls,” he said.

Mr. Lu said that it would be “incredible if it were all coincidence.”

“At the very least,” he said, “it shows us a culture that we often don’t credit enough was far more advanced than we ever thought before.”

From a study of a few hundred examples, Mr. Lu and Dr. Steinhardt determined that the technique was fully developed two centuries later in mosques, palaces, shrines and other buildings. They noted that “a nearly perfect quasi-crystalline Penrose pattern” is found on the Darb-i Imam shrine in Isfahan, Iran, which was built in 1453. The researchers described how the architects there had created overlapping patterns with girih tiles at two sizes to produce nearly perfect quasi-crystalline patterns.

In the report, Mr. Lu and Dr. Steinhardt said the examples they had studied so far “fall just short of being perfect quasi crystals; there may be more interesting examples yet to be discovered.”

In a separate article in Science, some experts in the math of crystals questioned if the findings were an entirely new insight. In particular, Emil Makovicky of the University of Copenhagen in Denmark said the new report failed to give sufficient credit to an analysis he published in 1992 of mosaic patterns on a tomb in Iran.

Mr. Lu and Dr. Steinhardt said they regretted what they called a misunderstanding. They pointed out that the length of their report was strictly enforced by journal editors, but it did include two footnotes to Dr. Makovicky’s research. None of the referees or editors who reviewed the paper, Dr. Steinhardt said, asked for more attention to the previous research.

Although their work had some elements in common with Dr. Makovicky’s, Dr. Steinhardt said in an interview that their research dealt with not one but a “whole sweep of tilings” interpreted through a few hundred examples.

The article quoted two other experts, Dov Levine and Joshua Socolar, physicists at the Israel Institute of Technology in Haifa and Duke University, respectively, as agreeing that Dr. Makovicky deserved more credit. But, the article noted, they said the Lu-Steinhardt research had “generated interesting and testable hypotheses.”

[read more in The New York Times>>>]

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Se acumula, se olvida

Advanced Math in Medieval Architecture
K. Dudley and M. Elliff
Advanced Math in Medieval Architecture

In tile mosaics on medieval Islamic buildings, scientists see patterns suggesting that the designers had made a conceptual breakthrough in mathematics.




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jueves, febrero 22, 2007

Os filhos do Bill Gates

Bill Gates controla o uso do computador dos filhos
Fundador da Microsoft diz que crianças só têm 45 minutos para jogar no computador e navegar na internet durante a semana. Clique e saiba mais


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Libertad de expresión

Egipto condena a un blogger
Cuatro años de cárcel y trabajos forzosos fue la sentencia para un blogger por haber criticado públicamente al Islam y al presidente egipcio.


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martes, febrero 20, 2007

Los chicos se divierten

Teen 'sport killings' of homeless on the rise

• Number of attacks on homeless at highest level in almost a decade
• 122 attacks, 20 murders in 2006, according to National Coalition for the Homeless
• For some teens, "this passes as amusement," expert says
By Ashley Fantz
CNN
story.rex.2003.pawlowski.jpg

Forty-nine-year-old Rex Baum, seen in 2003, was an alcoholic and homeless but worked at a gas station and did odd jobs around Milwaukee.



MILWAUKEE, Wisconsin (CNN) -- All Nathan Moore says he wanted to do was smoke pot and get drunk with his friends.

Killing Rex Baum was never part of the plan that day in 2004.

"It all started off as a game," Moore said.

The 15-year-old and his friends were taunting the homeless man -- throwing sticks and leaves -- after having a couple of beers with him.

No big deal, Moore says, but he's sorry for what came next.

It was a mistake, he said, a sudden primal surge that made him and his friends Luis Oyola, 16, and 17-year-old Andrew Ihrcke begin punching and kicking Baum.

"Luis says 'I'm gonna go hit him,' We're all laughing, thought he was joking around,'" but he wasn't, Moore concedes. "We just all started hitting him."

They hurled anything they could find -- rocks, bricks, even Baum's barbecue grill -- and pounded the 49-year-old with a pipe and with the baseball bat he kept at his campsite for protection.

Ihrcke smeared his own feces on Baum's face before cutting him with a knife "to see if he was alive," Moore said.

After destroying Baum's camp, the boys left the homeless man -- head wedged in his own grill -- under a piece of plastic where they hoped the "animals would eat" him.

Then, Moore says, they took off to grab a bite at McDonald's.

Baum's murder was indicative of a disturbing trend.

A National Coalition for the Homeless report says last year, there were 122 attacks and 20 murders against the homeless, the most attacks in nearly a decade. (Coalition report on 2006 homeless attacks)

Police found Baum's body two days after the teens attacked him.

They bragged about it around town. Police picked them up and they described what happened.

Ihrcke told police that killing "the bum" reminded him of playing a violent video game, a police report shows.

All three teens pleaded no contest to first degree reckless homicide charges and went to prison.

Moore recently turned 18 at Columbia Correctional Institution in Portage, Wisconsin, where he is serving a 15 year sentence.

"When [the beating] stops, you say, 'What did we just do?'" he told CNN. "There's no rational explanation." (Watch teen explain how "game" became tragedy Video)
Teenage 'amusement'

"It's disturbing to know that young people would literally kick someone when they're already down on their luck," said Michael Stoops, the executive director of the Washington-based National Coalition for the Homeless. "We recognize that this isn't every teenager, but for some this passes as amusement."

Criminologists call these wilding sprees "sport killing," -- largely middle-class teens, with no criminal records, assaulting the homeless with bats, golf clubs, paintball guns. (Watch how nights are cold, fearful for Milwaukee homeless Video)

Some teens have even taped themselves in the act. Others have said they were inspired by "Bumfights," a video series created in 2002 and sold on the Web that features homeless people pummeling each other for the promise of a few bucks.

A segment called "Bum Hunter," hosted by a Crocodile Hunter-like actor wearing a safari outfit, shows him "tagging" homeless people by pouncing on them and binding their wrists.

The distributors of "Bumfights" have claimed they've sold hundreds of thousands of copies.

But the company has had to deal with a couple of legal issues unrelated to the Baum case.

Last year, three former homeless stars of "Bumfights" won a civil suit against filmmakers. Santa Monica attorney Mark Quigley, who represented Rufus Hannah, known as "Rufus the Stunt Bum" to series' fans, said he is unable to disclose the amount of the settlement.

Also, in July 2006, a California judge ordered "Bumfights'" producers Ryan McPherson and Zachary Bubeck to spend 180 days in jail for failing to perform community service related to guilty pleas they previously entered to charges of staging illegal street fights.

"Bumfights" directors did not answer CNN's request for an interview.
Attacks across the nation

Incidents of teen-on-homeless violence dotted the map last year. Florida racked up at least six such attacks in 2006. (Homeless attack across U.S.)
[...]
[read more>>>]


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viernes, febrero 16, 2007

Jaques Chirac y un pensamiento de estilo borgeano.


"No fue Colón quien descubrió América, sino los vikingos, cinco siglos antes y tuvieron la elegancia de destruirse ellos mismos".

Jacques Chirac


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jueves, febrero 15, 2007

No por mandato de Dios

DETUVIERON A UN CURA POR SECUESTROS Y ASESINATOS DURANTE LA DICTADURA
Otra sotana manchada de sangre
El sacerdote Miguel Regueiro fue capellán militar y está acusado del secuestro de tres jóvenes y la sustracción de un bebé.

Por Camilo Ratti y Victoria Ginzberg
Entre 1975 y 1978 fue capellán militar del batallón de Combate de Ingenieros de San Nicolás. El teniente coronel Manuel Saint Imant, jefe del área 132, lo consideraba “un aliado del Ejército”. En el barrio cordobés Las Violetas, donde tiene una de sus varias capillas, era conocido por su pasado y simpatía castrense. El sacerdote Miguel Regueiro fue detenido el lunes por orden del juez federal Carlos Villafuerte Ruzo. Está acusado de haber participado en el secuestro y asesinato de tres jóvenes y de la sustracción de un bebé.
María Cristina Alvira y Horacio Arístides Martínez, jóvenes estudiantes de la Universidad Nacional del Litoral y militantes de la Juventud Peronista Universitaria, se instalaron en San Nicolás en 1975. En abril de 1977 la pareja y Rosa Raquel, la hermana de María Cristina, fueron secuestrados en un operativo en el que actuaron las “fuerzas conjuntas”. El hijo de unos pocos meses de María Cristina y Horacio fue dejado con un vecino, a quien luego le ordenaron entregarlo al capellán militar Regueiro.
Alertada por el vecino, la familia buscó al bebé y a fuerza de insistencia logró recuperarlo. Para ello, la madre de María Cristina tuvo que ir a una casa en las afueras de San Nicolás con el cura, donde, señaló, había “muchos otros niños y bebés”. La mujer le rogó a Regueiro que le dé información sobre su hija y su yerno. La respuesta fue que “eran unos delincuentes subversivos que querían matarlo a él y al teniente coronel” (Manuel Saint Imant) y que no le iba a decir dónde estaban.
La detención de Regueiro, pedida por el fiscal Juan Murray y la familia de las víctimas, se concretó el lunes. Ayer, el sacerdote fue indagado durante cuatro horas y quedó alojado en la delegación de San Nicolás de delitos federales y complejos de la Policía Federal.
En la misma causa se investiga la desaparición de otros jóvenes, compañeros de militancia de Alvira y Martínez. Todos estaban ligados con el trabajo social en la diócesis de San Nicolás, dirigida por el obispo Carlos Horacio Ponce de León, cuyo asesinato es objeto de otro expediente judicial.
Las Violetas
Regueiro estuvo muchos años en Córdoba como capellán del Liceo Militar General Paz. En 1992 se incorporó a la arquidiócesis provincial como sacerdote diocesano. El arzobispado, en ese momento presidido por el fallecido Raúl Primatesta, lo designó como su representante en la capilla de Parque República, un barrio aledaño a Las Violetas, una de las comunidades más pobres de la zona oeste de la capital.
En las calles de esa populosa barriada cordobesa los vecinos se dividen entre quienes lo quieren “por toda la obra que hizo aquí y en otros barrios”, y los otros, como Susana. Sentada en la vereda de su casa, frente a la parroquia Santa Teresa de Jesús, la construcción más nueva y coqueta de un zona muy humilde, con chicos que juegan en la calle al ritmo del cuarteto o la cumbia, la mujer aseguró que el cura arrestado es “prejuicioso y discriminatorio hacia los más pobres o los que no participamos activamente de sus actividades en la parroquia”.
Pedro Pérez, el ordenanza que colabora desde hace once años con Regueiro en el mantenimiento de la capilla, dijo que desconoce cuál fue la actuación de éste en los años ’70: “Lo único que él me contaba era todo lo bueno que habían hecho en San Nicolás”. También sentadas en la vereda “por una humedad que no se aguanta”, sorprendidas como todos en el barrio por la detención de Regueiro, Mabel y Cora contaron que “don Pedro solía acompañar al cura al comando”. El “comando” es el Tercer Cuerpo de Ejército, ubicado a unos pocos kilómetros del barrio Las Violetas.


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miércoles, febrero 14, 2007

Amores que matan

San Valentín perjudica ecosistema en Kenia
La tradición de enviar flores por el Día de San Valentín está arruinando el ecosistema en la zona del lago Naivasha, en Kenia, de donde miles de rosas son llevadas al Reino Unido.


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lunes, febrero 12, 2007

A Perfect Score On Math SAT

Boy, 10, gets perfect score on SAT math test Video

10-Year Old Gets Perfect Score On Math SAT

Meet ten-year-old Darryl Wu. Like most kids he loves to ride his bike. And like most ten-year-olds he likes to win.

His trophies line the fireplace mantle and book shelves in his home. His specialities - math and chess. Still, even with the array of awards and trophies his latest victory is somewhat unexpected.

Late last year the fifth-grader decided to join his brother and take the college entrance exam - the SAT's.

Darryl says, "7th and 8th graders can start taking the SAT. So my brother is in 7th grade so I was wondering how I would do."

How did Darryl do? How about a perfect score - 800 in the math section.

Darryl says, "Although I was half expecting it, it was still very exciting. The section didn't seem that hard really."

Just for perspective the average math score was 518.

Darryl credits his love of learning to his parents who've always encouraged him. Darryl says, "They like to try and motivate me."

Darryl's mom, Monica says, "I think what we did was just let them pick what they want to do…what they want to study or read."

Darryl's room is filled with advanced books and science magazines. Reading is a favorite past time.

Darryl's future plans is to graduate from fifth grade and maybe he'll be taking the SAT again - after all he still needs to work on getting perfect scores in reading and writing.




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sábado, febrero 10, 2007

Tradición nacional

Más claro echale agua

El presidente de OSE aclaró que en Punta del Este algunos gastaron para sus piscinas, en un mes, lo mismo que consume un pueblo del Interior
Ver nota completa

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jueves, febrero 08, 2007

En defensa de la civilización, dijo?

[googlevideo=http://video.google.com/googleplayer.swf?docId=-6080990140705840637]

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Khurbn

Shoá: El Holocausto

La semana pasada se cumplió un nuevo día de recordación del mayor crimen cometido por el nazismo durante la Segunda guerra mundial, el Holocausto. Hemos querido aportar la peor de las condenas, la de brindar la más completa información posible sobre esta vergüenza para todo el género humano.

El Holocausto, también conocido como Shoah o Shoá (en hebreo, ; en Yiddish, Halokaust, o más precisamente Khurbn), es el nombre que se aplica a la persecución y genocidio de los judíos, y de algunos otros grupos minoritarios de Europa y norte de Africa, llevado a cabo por la Alemania nazi durante la Segunda Guerra Mundial mediante el asesinato sistemático e industrializado.

[Leer más>>>]

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Otro signo de la nueva sociedad

¿Hallazgo arqueológico con Google Earth?
Llevaba 15 días intrigada con una mancha que había visto navegando con Google Earth por el Mar Menor. Ayer se decidió y lo notificó a la Dirección General de Cultura de Murcia, España. La arquitecta Concha Roca había descubierto indicios de lo que podría ser un gigantesco poblado romano fortificado.
Según el sitio 20minutos, el poblado está en las coordenadas 37° 46´ 22.49" N y 0° 45´ 10.37" O.
De confirmarse este hallazgo, que no está documentado, Concha Roca podría no sólo bautizarlo como le venga en gana, sino también investigarlo. Pero para esto último necesitaría el visto bueno de las autoridades
Según la arquitecta, que trabaja en la Consejería de Obras Públicas, lo primero que le hizo pensar que tenía delante un poblado romano fue su trama ortogonal.
En su opinión, siempre cautelosa, la mancha que aparece en Google Earth, pasado el Puerto Tomás Maestre, mide 1400 x 270 metros y está bajo el Mar Menor porque desde la época de los romanos, las aguas han subido 50 cm (datos confirmados por arqueólogos a la arquitecta Concha Roca).
Si se demuestran las sospechas de la arquitecta podría haber en La Manga, bajo las aguas del Mar Menor, vestigios de un posible poblado donde se asentaban los colonos llegados de Roma, que dividían el terreno siguiendo un modelo ortogonal y organizado.
En ese caso, tendría que estar protegido por la legislación sobre el patrimonio histórico de España y tiraría por la borda a cualquier proyecto urbanístico en la zona.
AFP


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miércoles, febrero 07, 2007

Madris

Al Gore imparte en Madrid una conferencia catastrofista sobre el cambio climático
Al Gore ofrece una mirada pesimista sobre el cambio climático en Madrid
El ex vicepresidente de Estados Unidos Al Gore ha asegurado hoy que la civilización "nunca" se ha visto tan amenazada como ahora, si bien ha considerado que "tenemos todo lo que necesitamos para salvarla", excepto voluntad política, aunque ha explicado que éste es "un recurso renovable".
Al Gore, que ha volcado sus esfuerzos durante los últimos años en la lucha contra el cambio climático, ha hecho estas consideraciones durante la conferencia 'El mayor problema actual de la humanidad: el calentamiento global y la acción para frenarlo' con la que ha abierto el primer Encuentro sobre Energía, Municipio y calentamiento global, que se celebra hoy y mañana.
El político norteamericano ha insistido insistió en que hay tiempo todavía "y tenemos muchas armas" para tratar de resolver el problema, a la vez que ha abogado por un endurecimiento del Protocolo de Kioto de lucha contra el cambio climático. Ha acusado a Estados Unidos de tener los índices más altos de emisiones de dióxido de carbono (CO2) y ha opinado que países emergentes como China no se comportarán responsablemente mientras no lo hagan los Estados más desarrollados.
El ex vicepresidente estadounidense ha reconocido que en la historia ha habido dos procesos de calentamiento similares, pero ha asegurado que el que se está produciendo en la actualidad "no es natural".

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Romeo y Julieta


Couple still hugging 5000 years on

Reuters | Wednesday, 7 February 2007

Reuters

ETERNAL EMBRACE: Archaeologists in Italy have discovered a couple buried 5000 to 6000 years ago, hugging each other.


ROME: Call it the eternal embrace. Archaeologists in Italy have discovered a couple buried 5000 to 6000 years ago, hugging each other.

"It's an extraordinary case," said Elena Menotti, who led the team on their dig near the northern city of Mantova.

"There has not been a double burial found in the Neolithic period, much less two people hugging – and they really are hugging."

Menotti said she believed the two, almost certainly a man and a woman although that needs to be confirmed, died young because their teeth were mostly intact and not worn down.

"I must say that when we discovered it, we all became very excited. I've been doing this job for 25 years. I've done digs at Pompeii, all the famous sites," she said.

"But I've never been so moved because this is the discovery of something special."

A laboratory will now try to determine the couple's age at the time of death and how long they had been buried.

[Read more>>>]

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martes, febrero 06, 2007

"He is completely heterosexual. That is something he discovered."


This handout photo released by New Life Church shows the Rev. Ted Haggard, president of the National Association of Evangelicals, in Sept. 2005 in Colorado Springs, Colo. (AP Photo)

Quote

"He is completely heterosexual. That is something he discovered. It was the acting-out situations where things took place. It wasn't a constant thing."

Rev. Tim Ralph

WHAT DO YOU THINK?




(AP) A leading evangelist who admitted to "sexual immorality" following allegations of sex with a male prostitute is convinced he is "completely heterosexual," said one of four ministers who oversaw three weeks of intensive counseling with the disgraced minister.

The Rev. Ted Haggard, a vocal opponent of gay marriage, also said his sexual contact with men was limited to the former male prostitute who came forward with sexual allegations, the Rev. Tim Ralph of Larkspur told The Denver Post for a story in Tuesday's edition.

"He is completely heterosexual," Ralph said. "That is something he discovered. It was the acting-out situations where things took place. It wasn't a constant thing."

Read more >>>

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lunes, febrero 05, 2007

Universidades en el mundo

http://www.webometrics.info
Top 3000 Universities
POSITION


WORLD RANK UNIVERSITY COUNTRY SIZE VISIB. RICH FILES SCHOLAR




















































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