sábado, 20 de agosto de 2011

Como hace 2.400 años


Como hace 2.400 años

DORILA VICTORIA FERNÁNDEZ-VIAGAS (Profesora de Lenguas Clásicas) - Coria del Río, Sevilla - 14/08/2011
A propósito del artículo de opinión de Mario Vargas Llosa -publicado en EL PAÍS el 31 de julio- sobre los efectos de Internet en nuestro cerebro, me dejó un poco perpleja el hecho de que hace más de 2.400 años los pensadores griegos clásicos, y concretamente Platón, hubieran advertido de peligros semejantes, en este caso referidos a la invención de la escritura.
Concretamente en el diálogo Fedro (274c-275a) dice Platón: "La escritura conserva la sabiduría y alarga el tiempo de los hombres más allá de su propia vida, pero esta confianza en la escritura puede provocar el olvido por dejación del esfuerzo". Igual que Vargas Llosa previene sobre el riesgo de trivializar el conocimiento y carencia de profundidad en el mismo al consumirlo con una rapidez no exenta a menudo de superficialidad, Platón advierte de que los hombres que fían todo a la escritura y no ejercitan la memoria y la reflexión, "habiendo oído hablar de muchas cosas sin instrucción, darán la impresión de conocer muchas cosas, a pesar de ser en su mayoría unos perfectos ignorantes y serán fastidiosos de tratar al haberse convertido en vez de sabios en hombres con la pretensión de serlo".
No obstante, los 2.400 años transcurridos invitan al optimismo, pues no cabe duda que la escritura representó una aportación esencial al saber, como sin duda lo son Internet y las nuevas tecnologías de la comunicación, aunque ello no sea óbice para reflexionar sobre el uso que se hace de las mismas.

Chromosomes and Cancer


Chromosomes and Cancer

Two new papers identify how abnormal chromosome count, or aneuploidy, might relate to cancer.

By Jef Akst | August 18, 2011
 
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Wikimedia Commons
Wikimedia Commons
Aneuploidy—when the cells of an organism contain more or fewer than the standard number of chromosomes for its species—is found in greater than 90 percent of all human cancers. But how exactly it relates to cancer, and whether it is a cause or merely a consequence of genomic instability, has long been a mystery. Two new studies published today (August 18) in Science show that it’s probably both, pointing to a gene defect that can cause aneuploidy, and elucidating the disastrous effects of aneuploidy on a cell’s genome.
“Aneuploidy is found in virtually all cancers, yet very little is known about its origins or its effects,” said a cancer biologist Bert Vogelstein at Johns Hopkins Medicine, who was not involved in the research. “These two papers provide some really excellent clues to what’s going on.”
The first paper, from Todd Waldman’s group at Georgetown University School of Medicine, identifies a potential cause of aneuploidy—a gene that encodes a protein subunit of the cohesin complex, which plays a key role in correctly separating sister chromatids during cell division. An MD/PhD student in Waldman’s lab, David Solomon, was examining brain tumors for missing genomic regions when he stumbled upon a sample that was missing the gene STAG2. He then looked at a dozen or so other brain tumors and found that several of them were similarly not expressing STAG2.
“And then we expanded our study to a variety of other tumor types and found that inactivation of STAG2 was actually quite common in a diverse range of human cancers,” Waldman said. Specifically, the team found evidence of mutated or missing STAG2 in some 20 percent of brain tumors, 20 percent of melanomas, and 20 percent of Ewing’s sarcomas, a pediatric tumor.
To see if this gene defect could indeed lead to the aneuploidy characteristic of the tumor cells they were examining, the researchers repaired STAG2 in two brain tumor lines, and found that the cells subsequently became less aneuploid. The cell populations showed less variation in the numbers of chromosomes they carried, and in some cases, the actual chromosome number was reduced, bringing it closer to normal. Conversely, when the team induced a STAG2 mutation in otherwise normal cells, the cells almost universally gained a chromosome. “I think that this work, together with some previous work, strongly implicates the inactivation of cohesin in general as a cause of aneuploidy in cancer,” Waldman said.
The second study looked at the consequences of aneuploidy. Geneticist Angelika Amon of the Massachusetts Institute of Technology and her colleagues had already shown that aneuploidy puts stress on the protein quality control pathways of the cell. “When you now have an extra chromosome or multiple extra chromosomes, all of a sudden thousands of proteins are imbalanced, and the cell has to deal with that,” she explained. “But we wanted to know if these protein imbalances could cause stress on the genome maintenance functions of the cell.”
So Amon and her team created haploid yeast cell lines with a single additional chromosome, and examined the cells for signs of genomic instability. Sure enough, the aneuploid yeast lines showed increased chromosomal instability, increased mitotic recombination, and increased structural abnormalities, such as those caused by double-strand breaks in the DNA. “Aneuploidy impacts basically all genome replication and segregation functions,” Amon said.
Exactly how an abnormal number of chromosomes causes such instability is unclear. One possibility is that having too many copies of a particular gene or set of genes increases the chance of genomic disruption. Or, the stress that results from the imbalance of protein levels overall could somehow lead to genomic instability. Additionally, it could simply be the increased number of chromosomes that causes the problem.
“I think the Amon paper emphasizes this, that cells with grossly abnormal numbers of chromosomes have some level of chromosome instability just by virtue of their abnormal chromosome count,” Waldman said. “When cells are in a state of aneuploidy, their mitotic machinery gets somewhat confused by the abnormal chromosome count and that perpetuates the instability.”
These results were obtained in haploid yeast cells, however, which is “a fairly reductionist model system,” said cell biologist Duane Compton at Dartmouth College in New Hampshire, who did not participate in the study. “So the overall implications for human cancer are really not entirely clear.” Human cells, for example, have mechanisms that guard against such genomic chaos, such as the tumor suppressor protein p53, which signals the cells to stop dividing once the genome gets to be in such disarray.
Still, “I find the observation very, very interesting,” Compton said. “Waldman is showing that there’s a single gene mutation that causes aneuploidy. Amon is saying if you’re aneuploid, you get all sorts of other genomic changes. Taken together, the grand implication is that mutation of one single gene can be responsible for all sorts of instability seen in tumors, which to me is extraordinary.” Clearly there are some holes to fill in—namely whether aneuploidy will similarly cause genomic instability in mammalian cells, he added, but “if that were true, it would be hugely powerful.”
J.M. Sheltzer et al., “Aneuploidy drives genomic instability in yeast,” Science, 333: 1026-30, 2011.
D.A. Solomon et al., “Mutational inactivation of STAG2 causes aneuploidy in human cancer,” Science, 333: 1039-43, 2011.

Desintermediación en industria de la comunicación / Sobrevivir al postdigitalismo.


Desintermediación en industria de la comunicación / Sobrevivir al postdigitalismo.
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Los productores de este Digitalismo.com, Carlos Scolari y un servidor, escogemos agosto para viajar en familia, participar en eventos en América Latina, disfrutar del verano europeo y pensar el próximo ciclo profesional que comienza en septiembre. Tiempo de relax y ocio creativo. Poca producción real. Eso disminuye a casi cero la escritura en nuestro blog. Así que para no quedar desconectados con nuestros fieles lectores -sobre todo los del hemiesferio sur que no están de vacaciones- va una breve selección de 10 post que he escrito durante 2011 y que quiero re-compartir con vosotros. En septiembre volveremos a toda máquina con nuestro ritmo de producción habitual. Y siempre felices de estar aquí.











Edumorfosis: Congreso de EduBlogs

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FEAPS, cuadernos de buenas prácticas



SÁBADO 20 DE AGOSTO DE 2011

FEAPS, cuadernos de buenas prácticas

La mayoría de vosotros ya los conocereís, algunas vez os he hablado de esta entidad, se trata de FEAPS, la Federación de Organizaciones en favor de Personas con Discapacidad Intelectual. Se trata de una ONG que defiende los derechos de las personas con diversidad intelectual o del desarrollo y de sus familiares.

Os enlazo varios documentos relacionados en su filosofía, además de su web:



Hoy me gustaría presentarios los Cuadernos de Buenas Prácticas que han editado, unas monografías muy prácticas con un enfoque realista. Las enlazo a continuación. Espero os sean útiles.

Guía "Defendemos nuestros derechos en el día a día"Guía "Defendemos nuestros derechos en el día a día"

Formación en Autodeterminación para FamiliasFormación en Autodeterminación para Familias
Autodeterminación
Pulsa para obtener el PDF.Libro Blanco de la participación en Aspanias Burgos


Pulsa para obtener el PDF.
Guía REINE. Reflexión Ética sobre la Inclusión en la Escuela  
Pulsa para obtener el PDF.Servicios de Respiro Familiar 

Pulsa para obtener el PDF.Un enfoque de la discapacidad intelectual centrado en la familia 
Pulsa para obtener el PDF.Guía de buenas prácticas de comunicación interna 








Pulsa para obtener el PDF.De Padres a padres 
Pulsa para obtener el PDF.Apoyo Conductual Positivo. Algunas herramientas para afrontar las conductas difíciles
Pulsar para obtener PDF: 857 kb.





Pulsar para obtener PDF: 857 kb.






Pulsar para obtener PDF: 373 kb.




Pulsar para obtener PDF: 2,5 Mb.
Obtener PDF: 471 kb.








Obtener PDF: 2.157 kb.
Obtener PDF: 648 kb.


Obtener PDF: 1.074 kb.


Descarga cuaderno en PDF: 765 kb.


Blog de Terapia Ocupacional, Psicomotricidad, Atención Temprana y Promoción de Autonomía: FEAPS, cuadernos de buenas prácticas

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viernes, 19 de agosto de 2011

En este día


ON THIS DAY

On This Day: August 19

On Aug. 19, 1934, a plebiscite in Germany approved the vesting of sole executive power in Adolf Hitler as Fuhrer.
On Aug. 19, 1883, Gabrielle "Coco" Chanel, the influential French fashion designer, was born. Following her death on Jan. 10, 1971, her obituary appeared in The Times.

On This Date

1929The comedy "Amos 'n' Andy" made its network radio debut on NBC.
1960A tribunal in Moscow convicted American U-2 pilot Francis Gary Powers of espionage.
1969Jazz trumpeter Miles Davis began three days of recording sessions that yielded the album "Bitches Brew."
1976President Gerald R. Ford won the Republican presidential nomination at the party's national convention in Kansas City.
1977Comedian Groucho Marx died at age 86.
1994President Bill Clinton halted the nation's three-decade open-door policy for Cuban refugees.
1996A judge sentenced former Arkansas Gov. Jim Guy Tucker to four years' probation for his Whitewater crimes.
2004The Internet search engine Google went public.
2005A Texas jury found pharmaceutical giant Merck & Co. liable for the death of a man who'd taken the once-popular painkiller Vioxx.
2010A federal grand jury indicted retired baseball player Roger Clemens for allegedly lying to Congress about steroid use. (Clemens' trial this year ended in a mistrial.)
2010The last American combat brigade exited Iraq, seven years and five months after the U.S.-led invasion began.

Current Birthdays

Kevin Dillon, Actor (“Entourage”)
Actor Kevin Dillon ("Entourage") turns 46 years old today.
AP Photo/Evan Agostini
Kyra Sedgwick, Actress (“The Closer”)
Actress Kyra Sedgwick ("The Closer") turns 46 years old today.
AP Photo/Vince Bucci
1939Ginger Baker, Rock musician (Cream, Blind Faith), turns 72
1940Jill St. John, Actress, turns 71
1942Fred Thompson, Actor, former U.S. senator, R-Tenn., turns 69
1946Bill Clinton, Former president, turns 65
1948Tipper Gore, Wife of former Vice President Al Gore, turns 63
1948Gerald McRaney, Actor ("Major Dad"), turns 63
1953Mary Matalin, Political consultant, turns 58
1955Peter Gallagher, Actor, turns 56
1956Adam Arkin, Actor, turns 55
1960Morton Andersen, Football player, turns 51
1963John Stamos, Actor ("Full House'), turns 48
1966Lee Ann Womack, Country singer, turns 45
1967Tabitha Soren, MTV reporter, turns 44
1969Matthew Perry, Actor ("Friends"), turns 42
1970Fat Joe, Rapper, turns 41
1975Tracie Thoms, Actress ("Cold Case"), turns 36
1982Erika Christensen, Actress, turns 29
1989Romeo, Rapper, turns 22

Historic Birthdays

73John Flamsteed 8/19/1646 - 12/31/1719
English founder of the Greenwich Observatory
50Jeanne Becu du Barry 8/19/1743 - 12/8/1793
French mistress of Louis XV
73Seth Thomas 8/19/1785 - 1/29/1859
American clock manufacturer; pioneered mass production
94Bernard Baruch 8/19/1870 - 6/20/1965
American financier and adviser to United States presidents
73Georges Enesco 8/19/1881 - 5/4/1955
Romanian violinist and composer
91Ton Duc Thang 8/19/1888 - 3/30/1980
Vietnamese communist leader; succeeded Ho Chi Minh
84Alfred Lunt 8/19/1892 - 8/3/1977
American actor
88Colleen Moore 8/19/1900 - 1/25/1988
American actress
68Ogden Nash 8/19/1902 - 5/19/1971
American poet
74James Gould Cozzens 8/19/1903 - 8/9/1978
American novelist
70Gene Roddenberry 8/19/1921 - 10/24/1991
American creator of the Star Trek series