Links for 2011-02-12

"With the entire world watching Egypt as it celebrates the uprooting of its dictator, Yemenis are calling for help and the world's media attention.

On Twitter, the calls came loud and clear. A rally started in Sanaa, the Yemeni capital, in celebration of the ousting of Hosni Mubarak. Soon, it turned into an anti-Saleh protest, calling for an end of Ali Abdullah Saleh's rule.

Police surrounded the protesters, and there were reports of fire shots. Wounded protesters, taken to hospitals, were arrested - at least that is what I understood from a frenzy of tweets.

To add to the confusion, and in the absence of many citizen journalists in Yemen, there seems to be unrest in Aden, to the South, and in Taiz.

Here are some of the reactions I have been able to gather from Twitter. The last the three tweets list tweeps reporting on Yemen, some from the ground - voices we will have to watch closely to figure out if Yemen will go Tunisia's and Egypt's way or not:"

"The West African nation of Gabon is experiencing a popular revolt against the rule of President Ali Bongo Ondimba, son of long-time strongman Omar Bongo who died only months before his son was elected in October 2009. Citing allegations of election fraud, opposition leaders formed a breakaway government on January 26 with former presidential candidate André Mba Obame as the self-declared president.
Thousands of opposition supporters took to the streets in the nation's capital, Libreville, on January 29, and were faced with violent suppression from the army. Protests have spread to other cities, and crackdowns have become increasingly fierce as the current wave of popular protests demanding free elections sweeping the African continent (Tunisia, Egypt and Côte d'Ivoire) has made the Gabonese government especially wary. The "unofficial" government went into hiding in the offices of the UNDP where they have remained for more than two weeks."

"Apart possibly from high-energy accelerators, there are no other engineering systems in existence today in which both special and general relativity have so many applications. The system is based on the principle of the constancy of c in a local inertial frame: the Earth-Centered Inertial or ECI frame. Time dilation of moving clocks is significant for clocks in the satellites as well as clocks at rest on earth. The weak principle of equivalence finds expression in the presence of several sources of large gravitational frequency shifts. Also, because the earth and its satellites are in free fall, gravitational frequency shifts arising from the tidal potentials of the moon and sun are only a few parts in and can be neglected."