Swatting at mosquitoes is a great start, but if we really want to cut down on the hundreds of millions of malaria cases they cause every year, we're going to need some more effective weapons. Now, researchers from Johns Hopkins have used the CRISPR/Cas9 gene editing tool to engineer mosquitoes that are highly resistant to the malaria parasite, by deleting one specific gene.
      According to the latest report from the World Health Organization, there were 216 million cases of malaria in 2016, resulting in 445,000 deaths. Female Anopheles gambiae mosquitoes are the primary culprit, and over the last few years scientists have engaged in all kinds of genetic warfare against the parasites and the insects that spread them.
      In 2011, a UC Irvine team modified mosquitoes so that females of the species couldn't fly. They would die where they hatched, while the males would fly off, mature and mate with wild females which would unknowingly pass the deadly mutation down to their offspring. Other genetic tweaking turned the insects' immune systems against the malaria parasite, made mosquitoes unable to sniff out humans, or crippled larvaeby silencing crucial development genes.
      The new study, conducted by researchers at Johns Hopkins Bloomberg School of Public Health, targeted a gene called FREP1. This gene encodes for a specific immune protein that, for reasons not fully understood, helps the malaria parasite survive in the mosquito's gut. By snipping out FREP1 using the genetic scissors of CRISPR/Cas9, the team was able to reduce the likelihood of the malaria parasite surviving long enough to mature to the stage where it can harm humans.
      "Our study shows that we can use this new CRISPR/Cas9 gene-editing technology to render mosquitoes malaria-resistant by removing a so-called host factor gene," says George Dimopoulos, senior author of the study. "The resistance to malaria parasites that's achieved by deleting FREP1 is remarkably potent."
      The technique was able to reduce the number of mosquitoes infected with malaria, and the researchers also found no trace in the bugs' saliva glands of sporozoites – the stage of the parasite that is transferred to humans through the bite.
      The genetic edit wasn't perfectly neat though. The team found that the engineered mosquitoes developed more slowly than their natural counterparts, were less likely to feed on blood and laid fewer eggs that were less viable. If the modified mozzies were released into the wild in this state, natural selection could wipe them out before they got the job done.
      "We're now making mosquitoes in which FREP1 will be inactivated only in the adult gut," says Dimopoulos. "We predict that when we do that, the mosquito won't suffer the same fitness costs."
      Once those kinks are ironed out, the genetically-modified mosquitoes could be released into the wild to spread their malaria resistance through the natural population. The researchers think that this could be a viable strategy, since the gene edits they've performed don't impact the insects' ability to survive and breed.
      "If you could successfully replace ordinary, wild-type mosquitoes with these modified mosquitoes, it's likely that there would be a significant impact on malaria transmission," says Dimopoulos.

      In August 1977, the Ohio State University Radio Observatory picked up a radio transmission from the Sagittarius constellation that was so strong it inspired the astronomer who discovered it to write "Wow!" in the margin of the data printout. Almost 40 years later, researchers from the Center for Planetary Science may have finally solved the mystery of the Wow! Signal's origin, and it's bad news for alien hopefuls: it was probably a comet.
      At the time the signal was spotted, Ohio State's "Big Ear" observatory was specifically searching for transmissions that could be evidence of extraterrestrial civilizations. Based on the work of earlier astronomers, the team determined that a message of intelligent origin would most likely be transmitted at a frequency of 1,420 MHz – the electromagnetic frequency of hydrogen – and that the Big Ear would "hear" it for 72 seconds, since that's how long the observatory could focus on one specific point in space.
      The Wow! signal was the first and only time exactly those criteria were met. Excited scientists tried training instruments on that region of space again, but the signal was never again recorded. Over the years, interference from Earth was ruled out, as were stellar bodies like planets, stars and asteroids. Aliens seemed unlikely, but tantalizingly, couldn't be ruled out.
      Last year, a group of researchers from the Center of Planetary Science proposed a new hypothesis that argued a comet might be the culprit. The frequency could be caused by the hydrogen cloud they carry, and the fact that they move accounts for why it seemingly disappeared. Two comets, named 266/P Christensen and P/2008 Y2 (Gibbs), happened to be transiting through that region of space when the Wow! signal was detected, but they weren't discovered until after 2006.
      To test the hypothesis, the team made 200 radio spectrum observations between November 2016 and February 2017. Sure enough, 266/P Christensen was found to emit radio waves at a frequency of 1,420 MHz, and to double check, the researchers moved their radio telescope by one degree. As expected, the signal vanished, and only returned when the telescope was trained back on the comet.
And 266/P Christensen wasn't an anomaly: the researchers tested three other comets, P/2013 EW90 (Tenagra), P/2016 J1-A (PANSTARRS), and 237P/LINEAR, and found they all emit signals at the same frequency.
      Whether the Wow! signal was caused by 266/P Christensen or another comet, it seems that one of the most enduring astronomical mysteries has been put to rest.
      The research was published in the Journal of the Washington Academy of Sciences.

Autonomous vehicles are getting much better at sensing their surroundings, but even they still need to be able to directly see a hazard to react to it. Now, a Stanford team is developing a laser-based system that may allow driverless cars to see around blind corners, and come to a stop before a child runs out or another car speeds by.
In order to image objects beyond direct line-of-sight, the technique involves bouncing laser pulses around a corner, off the desired object and back. A highly sensitive sensor captures the returning photons of light, an algorithm analyzes them and the end result is a fuzzy snapshot of something lurking just out of sight.
As high-tech as it sounds, this isn't the first time scientists have successfully pulled off this kind of light show. A team from MIT was experimenting with a similar system in 2012, and in 2014 European and Canadian researchers were able to recreate "light echoes" of hidden objects.
The Stanford scientists say their new contribution is mostly on the mathematical side. Since light is scattered by the objects it hits, they can bounce back to the sensor from almost anywhere, resulting in a lot of "noise" that can wash out the desired target. To help cut through, the team developed an advanced algorithm that can calculate the path taken by the captured photons, and use that to reconstruct the object.
"A substantial challenge in non-line-of-sight imaging is figuring out an efficient way to recover the 3D structure of the hidden object from the noisy measurements," says David Lindell, co-author of a paper describing the technique. "I think the big impact of this method is how computationally efficient it is."
The researchers say their algorithm can analyze the photon data in less than a second, and is efficient enough to run on a regular laptop. The problem in the way of practicality at the moment is the initial scans – in order to generate enough data about a hidden object, the system needs to fire off many pulses of laser light in a process that can take up to an hour. As it stands, that's not going to be much use for providing forewarning of a child about to run around a corner in front of a car.
The other major issue is ambient light. Under carefully-controlled lab conditions the system works fine, but take it outside into the bright light of day and the sensors get a little overwhelmed. That said, in outdoor tests the researchers found that the technology was able to clearly pick up highly reflective objects, such as high-visibility clothing and road signs and markers.
In future, the researchers plan to work on speeding up the scans, improving the system's ability to work in daylight and detect moving objects.
The research was published in the journal Nature. The team describes the project in the video below.

Every fundamental particle in the universe has an antiparticle, which has the same mass but the opposite charge. If a particle should ever meet its antiparticle, the two would annihilate each other in a flash of energy. But it's long been theorized that there's an exception to the rule, with certain particles that are actually their own antiparticles. Now, scientists from Stanford and the University of California have found the first strong evidence for this type of particle, which they dub the "angel particle."
The theory dates back to 1937, when physicist Ettore Majorana highlighted a gap in the fermion family of particles. Protons, electrons, neutrons, neutrinos and quarks are all fermions, and all have corresponding antiparticles, but according to Majorana's calculations, there should be particles that are their own antiparticles.
Since they have no charge, neutrons and neutrinos were the best candidates to be these Majorana fermions, but antineutrons have since been discovered. There's still a big question mark hanging over neutrinos though, and experiments are currently underway to determine if they are in fact their own antiparticle. However, the difficulty of the experiments means an answer is still more than a decade away.
In the meantime, the most likely way to find Majorana fermions is by looking for "quasiparticles." As the name suggests, these aren't quite natural particles, but they arise out of the collective behavior of electrons and have certain properties of particles. If that's hard to visualize, the Encyclopaedia Britannica explains the concept like bubbles in a drink: bubbles also arise out of the "collective behavior" of the chemicals in the drink, and although they aren't really independent objects, bubbles do have measurable properties like objects, including size, shape, etc.
In the same way, quasiparticles might not occur outside of very specific conditions, but they can be considered to be Majorana fermions if they exhibit all the right properties. Now Stanford and UC researchers say they've found a "smoking gun" signature that points to the presence of these hypothetical fermions.
"Our team predicted exactly where to find the Majorana fermion and what to look for as its 'smoking gun' experimental signature," says Shoucheng Zhang, one of the senior authors of the research paper. "This discovery concludes one of the most intensive searches in fundamental physics, which spanned exactly 80 years."
To make these quirky quasiparticles show themselves, the team carefully constructed their very specific "drink," made up of thin films of two quantum materials stacked on top of one another. The end result is a superconducting topological insulator, which allows electrons to move quickly along the edges of the material's surface but not through the middle. Adding a pinch of magnetic material to the mix made the electrons flow in one direction along one edge, and the opposite direction along the other.
The researchers then swept a magnet over the material, which caused all the electrons to slow down, stop and switch direction. The reversal happened in a jerky, staggered motion that the team likens to stairs in a staircase. Quasiparticles began to emerge from the material in pairs, traveling along the same path as the electrons, but there was a key difference: when they stopped and turned around, they did so in "steps" exactly half as high as the electrons. That's because each is essentially only half of a particle, since one out of each quasiparticle pair is lost along the way. And that phenomenon was exactly the evidence the team had been looking for.
Zhang proposes that the team's discovery be named the "angel particle" after the Dan Brown novel Angels and Demons, which features a bomb powered by the meeting of matter and antimatter. In the long run, Majoranas could find practical application in making quantum computers more secure.