The TEDxBahrialUKarachi show went on, despite a bombing in the city the day of the event. Why? To give hope. Photo: TEDxBahrialUKarachi

The city of Karachi, Pakistan, was on lockdown after bomb blasts claimed 57 lives in the midst of a tumultuous election. And on the day of TEDxBahriaUKarachi, yet another bomb shocked the area. Still, organizers Furqan Hussein and Sana Nasir boldly tread onward toward putting on a memorable event. “‘Ideas for Survival,’ our theme, sowed the idea of surviving in situations when there’s [little] or no hope,” Nasir tells the TEDx Blog in an interview. “The one thing we wanted our audience to take back [with them] was hope.”

These are the lengths some TEDx organizers go to in order to put on great events — dozens of which are held across the world every week. From these events, the TEDx team chooses four favorite talks each week, highlighting just a few of the enlightening speakers from the TEDx community and its diverse constellation of ideas. Below, listen to this week’s talks – on topics ranging from the data revolution to how we perceive pain.

Democracy’s data revolution: Simon Jackman at TEDxSydney
At TEDxSydney, Stanford researcher Simon Jackman demonstrates some of the ways in which an increased availability of data gives us a more accurate picture of electoral trends, the political zeitgeist, and the serious implications this has on the shape of public conversation. (Filmed at TEDxSydney.)

Pain is all about perception: Silje Endersen Reme at TEDxNHH
Nearly everyone will suffer from some form of back pain during their lifetime, often without a specific cause. At TEDxNHH, Silje Endersen Reme explains how our mental state can affect the way we perceive chronic and acute forms of back pain. (Filmed at TEDxNHH.)

Detecting cancer before it spreads: Raj Krishnan at TEDxSanDiego 2012
Curing cancer isn’t just about better treatment, says Raj Krishnan. If we can improve detection, patients will enjoy much better odds of survival and recovery. Krishnan demonstrates how doctors can use existing technology to scan for DNA markers of cancer cells — even before the patient is showing symptoms. (Filmed at TEDxSanDiego.)

African thumb piano jam: Hiroyuki at TEDxTokyo
At TEDxTokyo, Japanese artist Hiroyuki plays a remarkable musical performance on the kalimba — also known as the thumb piano. A handheld plucking instrument still relatively obscure in Western music, the kalimba is an ancient part of the heritage of several cultures in sub-Saharan Africa. (Filmed at TEDxTokyo.)

And here, some of the week’s highlights from the TEDx blog:

• Portrait of a TEDx’er: Austin Kleon
• Instagrammed: Completing the sentence “Before I die, I want to…” at TEDxRiyadh
• Quoted: Jackson Katz viral TEDx talk, “There are no women’s issues.”

As a young musician in Pakistan, TED Fellow Usman Riaz learned to play in the percussive guitar style by watching YouTube videos of Kaki King and her influences, including the founder of the technique, Preston Reed. Now, Riaz is among the artists and musicians calling for Pakistan to lift its seven-month-old ban on YouTube. Usman Riaz and Preston Reed: A young guitarist meets his heroTalking yesterday to the Express Tribune, Riaz said:

“Everything that I have learnt and achieved is a direct result of having a close connection to the online realm,” says Riaz. “YouTube [could] be the reason I became a TED Fellow. I would have never had a chance to speak on the TED stage or perform with Preston Reed — the man whose videos I used to watch on YouTube when I first picked up the guitar — if I didn’t have access to YouTube.”

Usman and friends have created a Facebook page called YouTube Aloud to gather information and fight the ban.

In September 2012, YouTube was banned in Pakistan during the furor over the film Innocence of Muslims, which many believed to be insulting to the prophet Mohammed. In early January, Pakistan’s government suggested it would lift the ban after installing filters, but the opening lasted about three hours before being shut again.

Riaz’s message: YouTube is too valuable for learning to be closed over one video. As he puts it in the Express Tribune: “Does it make sense to burn down an entire library just because you don’t agree with the contents of one of its books?”