Friday, June 24, 2011

El Sol se formó de manera diferente que el planeta tierra y el resto del sistema solar



El análisis de muestras obtenidas por la misión Génesis de la NASA indica que nuestro Sol y sus planetas interiores pueden haberse formado de manera diferente a como los científicos pensaban hasta ahora.

Los datos revelaron pequeñas diferencias en los tipos de oxígeno y nitrógeno presentes en el Sol y los planetas. Estos elementos se encuentran entre las más abundantes en nuestro sistema solar. Aunque las diferencias son leves, las consecuencias podrían ayudar a determinar cómo evolucionó nuestro Sistema Solar.

El aire en la Tierra contiene tres tipos diferentes de átomos de oxígeno, que se diferencian por el número de neutrones que contienen. Casi el 100 por ciento de los átomos de oxígeno en el sistema solar están compuestos de O-16, pero también hay pequeñas cantidades de isótopos de oxígeno más exóticos llamados O-17 y O-18. Los investigadores que estudian el oxígeno de las muestras de Génesis encontraron que el porcentaje de O-16 en el Sol es ligeramente más alta que en la Tierra, la Luna y los meteoritos. Los porcentajes de los otros isótopos fueron ligeramente inferiores.

"La implicación es que no nos formamos de los mismos materiales de la nebulosa solar que crearon el sol -algo cuyo cómo y por qué están por descubrir", dijo Kevin McKeegan, co-investigador de Génesis la Universidad de California, Los Ángeles y el autor principal de uno de los dos artículos publicado esta semana en Science al respecto.

El segundo estudio detalla la cantidad de nitrógeno en el Sol y los planetas. Como el oxígeno, el nitrógeno tiene un isótopo, N-14, que representa casi el 100 por ciento de los átomos en el sistema solar, pero también hay una pequeña cantidad de N-15. Los investigadores que estudian las mismas muestras dan cuenta de que cuando se compara a la atmósfera de la Tierra, el nitrógeno en el Sol y Júpiter tiene un poco más de N-14, pero el 40 por ciento menos N-15. Tanto el Sol y Júpiter parecen tener la misma composición de nitrógeno.

"Estos resultados muestran que todos los objetos del sistema solar, incluyendo los planetas terrestres, meteoritos y cometas, son anómalos en comparación con la composición inicial de la nebulosa de la que se formó el sistema solar", dijo Bernard Marty, coinvestigador de Génesis en el Centro de Investigaciones Petrographiques et Geochimiques en Nancy, Francia y autor principal del estudio. "La comprensión de la causa de tal heterogeneidad impactará en nuestro punto de vista sobre la formación del sistema solar."

Los datos fueron obtenidos del análisis de las muestras de viento solar recogidas por Génesis, concretamente del material expulsado desde la parte externa del sol. Este material puede ser considerado como un fósil de nuestra nebulosa debido a la preponderancia de la evidencia científica que sugiere que la capa externa de nuestro sol no ha cambiado apreciablemente por miles de millones de años.

"El sol contiene más del 99 por ciento de la materia existente en la actualidad en nuestro sistema solar, así que es una buena idea conocerlo lo mejor", dijo el investigador principal de Génesis Don Burnett, del Instituto de Tecnología de California en Pasadena, California "Si bien resulta más difícil de lo esperado, hemos respondido a algunas preguntas importantes, y como todas las misiones con éxito, genera un montón más".

Génesis se lanzó al espacio en agosto de 2000. La nave viajó a un millón de kilómetros de nuestro planeta, donde permaneció pasivamente durante 886 días entre 2001 y 2004 para recoger recoger muestras de viento solar.

El 8 de septiembre de 2004, la nave lanzó una cápsula de retorno de muestras qu eposteriormente aterrizó en el estado de Utah. Esto marcó el regreso de la primera muestra de la NASA desde la última misión lunar Apollo en 1972, y el primer material recogido más allá de la Luna.

Síguenos en Twitter: @ep_ciencia 

Thursday, June 16, 2011

Google introduces instant pages, voice-recognition, image search


Hardware y Software

Aimed to speed up search, simplify search in mobile devices

Search engine company Google has added new features and technology to improve its search feature.

Google's a new feature called Instant Pages, which is designed to help users of smartphones and other hand-held devices, displays Web pages in a user's browser before the search request is completed by the user.

The new feature reduces search query time by up to 5 seconds, said Google. It builds on an the Google Instant feature introduced in September 2010.

Google Fellow Amit Singhal said, "We see all this mobile traffic growing on top of our desktop (PC) traffic."

Singhal said, "We're obsessed with speed. We call speed the killer app. None of us have enough time, and last year's Google Instant was one of the biggest improvements we've made in getting information to users quicker."

Google has also introduced the voice-based search. Voice search allows users to tell the PC about their search query instead of typing. The feature is already used on Android-based smartphones.

The voice search feature will available on Chrome and Firefox browsers later this week. A microphone symbol near the search bar will represent the feature.

Another addition, Google has revealed is the image search feature. To use the feature, users would be required to provide some details of a picture. They may upload, drag and drop or paste a URL to do so. Google will then display results which are similar to the one mentioned by the user.


 


Wednesday, June 8, 2011

We should have been clearer over facial recognition technology: Facebook


Hardware y Software

Social networking site expanded the service which does not notify user before being tagged by others

After changing its users' privacy settings to automatically turn on a facial recognition feature, Facebook has admitted that it should have notified users about the changes.

Earlier, security company Sophos had reported that Facebook recently began changing its users' privacy settings. The aim was to use a facial recognition feature to ask Facebook friends to tag them.

However, privacy concerns were raised after it was revealed that Facebook does not give users the option to avoid being tagged in a photo.

Facebook has now said, "We should have been more clear with people during the roll-out process when this became available to them."

It added, "We launched Tag Suggestions to help people add tags of their friends in photos; something that's currently done more than 100 million times a day. Tag Suggestions are only made to people when they add new photos to the site, and only friends are suggested. If for any reason someone doesn't want their name to be suggested, they can disable the feature in their Privacy Settings."

The facial recognition feature was announced in December. Now it has been expanded from the US to "most countries", Facebook said.

"When we announced this feature last December, we explained that we would test it, listen to feedback and iterate before rolling it out more broadly," said a Facebook spokeswoman.


Thursday, June 2, 2011

Mobile phone radiation is a possible cancer risk: WHO


Hardware y Software

Major review places mobile phones alongside DDT and chloroform

The International Agency for Research on Cancer (IARC), a research group of the World health Organisation (WHO), has classified mobile phones as a possible cancer risk.

For years, advocacy groups have raised concerns about health risks posed by mobile phones. They cited a possible connection between excessive phone use and glioma, a fatal brain tumour. However, studies in the past could not establish health risks cause by mobile phone usage.

Now the research, which is considered a major review, has found that radiation from mobile phones are "possibly carcinogenic to humans."

The IARC announced the classification after an eight-day meeting in Lyon, France. The research group said that experts "reached this classification based on review of the human evidence coming from epidemiological studies."

The studies were assessed by 31 scientists from 14 countries. The findings could make the UN health body reconsider its guidelines on mobile phones, the scientists said.

The new classification puts mobile phone use in the same broad category as lead, DDT, chloroform, gasoline engine exhaust and coffee. Alcoholic drinks and night shift work are also on the 'carcinogen' list.

President of the work group and a scientist at the University of Southern California Jonathan Samet referred to rising cases of glioma, while making the announcement.

Samet said, "The conclusion means that there could be some risk, and therefore we need to keep a close watch for a link between cellphones and cancer."

Two studies showed a higher risk "in those that had the most intensive use of such phones," he said.

However, Sammet added that long-term effects of mobile phones are unknown.

"We simply don't know what might happen as people use their phones over longer time periods, possibly over a lifetime," Samet said.

In the study, the UK was represented by Simon Mann from the Health Protection Agency's Centre for Radiation, Chemicals and Environmental Hazards in Oxfordshire.


European online visitors grew to 365.3 million in April 2011: comScore



Netherlands registered highest average engagement at 31.3 hours per person

The number of unique visitors who went online in Europe reached 365.3 million in April 2011 with an average of 24.2 hours per person online, according to a study by comScore.

The study was conducted in 18 markets of European region. It revealed that among the markets, Netherlands registered the highest average engagement at 31.3 hours per person, 30% higher than the collective Europe average.

Google sites topped the European Web property in April by attracting 329.8 million unique visitors and reaching 90.3% of the total European Internet audience.

Microsoft sites stood second with 269.3 million visitors (73.7% reach), followed by Facebook.com with 236.9 million visitors (64.9% reach).

The study revealed that social networks continue to drive engagement among Europeans, with Russian social network VKontakte registering the highest average engagement among the top 30 properties. In April, visitors spent an average of 494.9 minutes or 8.2 hours on the site, representing a 22% increase from the previous month.

Russian Mail.ru Group ranked second at 293.9 minutes or 4.9 hours, followed by Facebook.com with an average of 283.6 minutes or 4.7 hours.

comScore said that in April 2011, the number of European users visiting the Travel category grew 11% in the past year, while Travel properties, which include online travel agents and accommodation sites, penetrated 44% of the European internet audience.

The UK continued to lead European markets in Travel category penetration at 66.5%, up 8 percentage points from a year ago.

Ireland and Spain also registered high penetration rates with 58.7% and 57.3% reach, respectively.

The research firm said that Expedia, which includes TripAdvisor Sites, Expedia Sites, and Hotels.com Sites, had most unique visitors in April 2011 with 21.7 million.