Month: June 2019

Enlarge (credit: James Pikul)

Lots of experimental robots involve a little bit of cheating. Rather than containing all the necessary electronics and energy sources, they have tethers and wires that provide power and control without weighing the robot down or taking up too much internal space. This is especially true for soft-bodied robots, which typically pump air or fluids to drive their motion. Having to incorporate a power source, pumps, and a reservoir of gas or liquid would significantly increase the weight and complexity of the robot.

A team from Cornell University has now demonstrated a clever twist that cuts down on the weight and density of all of this by figuring out how to get one of the materials to perform two functions. Like other soft robot designs, it pumps a fluid to cause its structure to expand and contract, powering movements. But in this case, the fluid is also the key component of a flow battery that powers the pumps. This allows them to put all the critical components on board their creation.

Going with the flow

So what's a flow battery? Batteries operate by having different reactions that take place at their two electrodes. For something like a lithium-ion battery, the intermediaries of these reactions—electrons and ions—immediately flow from one electrode to another, and the key chemicals spend almost all their time at the electrodes. In flow batteries, the chemical reactions still take place at the electrodes, but the chemicals reside in solution, rather than being confined to electrodes.

Enlarge / A capture shows the flood of "Ayaya" anime meme streams that took over Twitch's Artifact stream page in May. (credit: Know Your Meme)

In a federal lawsuit filed last week, Twitch accuses 100 unnamed defendants of breaking its terms of service by flooding the site's directory of Artifact game streams with inappropriate content, including "a video of the March 2019 Christchurch mosque attack, hardcore pornography, copyrighted movies and television shows, and racist and misogynistic videos."

Inappropriate or irrelevant streams are nothing new on Twitch, of course. The company's Trust and Safety team uses a variety of moderation tools to take down streams that violate the site's terms of service and ban the users behind them. But the company is taking the added step of a lawsuit in this case because, according to the complaint, "Defendants’ actions threatened and continue to threaten Twitch and the safety of the Twitch community."

"Twitch took down the posts and banned the offending accounts, but the offensive video streams quickly reappeared using new accounts," the complaint continues. "It appears that Defendants use automated methods to create accounts and disseminate offensive material as well as to thwart Twitch’s safety mechanisms."

Enlarge / "George, you've heard about this virus? Shall I cough on you, George?" (credit: Warner Bros.)

Today we’re presenting the third installment of my conversation with Naval Ravikant about existential risks. This interview first appeared in March, as two back-to-back episodes of the After On Podcast (which now features 50 unhurried conversations with world-class thinkers, founders, and scientists). Naval is one of tech’s most successful angel investors and the founder of multiple startups—including seed-stage investment platform AngelList. Please check out parts one and two of this conversation if you missed them. Otherwise, you can press play on the embedded audio player or pull up the transcript, both of which are below.

In this segment, Ravikant and I move on from yesterday’s topic of AI risk to the dangers inherent in the rise of synthetic biology, or synbio. Here, I should disclose that I am a hopeless synbio fanboy. I’ve gotten to know many of the field’s top figures through my podcast, and I essentially revere both their work and its potential. But even the most starry-eyed synbio booster cannot ignore the technology’s annihilating potential.

A big topic in today’s segment is a genetic hack performed on H5N1 flu. This nasty bug kills a higher proportion of those infected than even Ebola (as discussed in some detail in this piece on Ars yesterday). But since its wild form is barely even contagious to humans, it has historically killed very few of us. But in 2011, independent research teams in Wisconsin and Holland modified H5N1’s genome to make it virulently contagious.

Enlarge / Artist's impression of scientist doing DNA science. (credit: Roger Richter / Getty)

We're running a series of companion posts this week to accompany our special edition Ars Lunch Break podcast. This is the second of three guest posts centered around Rob Reid's TED talk from yesterday. Today, geneticist George Church weighs in with his thoughts and opinions on synthetic biology and a world-wide "DNA detector" net. Tomorrow we'll have a guest post from microbiologist Andrew Hessel.

Since the start of the millennium, we’ve improved the cost and quality of reading DNA 10 millionfold. This technology applies identically to our own genomes and to those of the most deadly pathogens. Yet we’ve barely begun to use this new "superpower" of DNA scrutiny to monitor our environment for threats to human health.

Many of the enabling technologies for highly distributed DNA detection networks are already here. For instance, we now have palm-sized devices that read DNA in nearly real time, and they can be attached to our smartphones—which themselves can append and transmit audio, video, and GPS data. Thousands are already using these new tools. They’re based on nanopore and other single-molecule electronics—which have very low reagent and tiny fabrication costs, and they are super-portable (a fraction the size of a phone).