The US Navy has revealed a video of the first commissioning tests of a railgun, a futuristic weapon that many people hope could shift the balance of power in naval warfare away from aircraft carriers and back to surface warships.

The Navy has been pursuing the railgun for years, but the project has been hamstrung by the sheer amount of power required to make it work, measured in megajoules of electricity.

UK-based BAE Systems appears to have made an operational railgun, however, and test fired it at the Naval Surface Warfare Center in Dahlgren, Virginia in November 2016. A short video of that test was made public by the Office of Naval Research on Tuesday.

Antibiotic resistance is one of medicine's most pressing problems. Now, a team from Korea is tackling this in a unique way: using bacteria to fight bacteria.

Before the discovery of penicillin in 1928, millions of lives were lost to relatively simple microbial infections. Since then, antibiotics have transformed modern medicine. The World Health Organization estimates that, on average, antibiotics add 20 years to each person's life. However, the overuse of antibiotics has put pressure on bacteria to evolve resistance against these drugs, leading to the emergence of untreatable superbugs.

Now, researchers at South Korea's Ulsan National Institute of Science and Technology (UNIST) aim to fight fire with fire by launching predatory bacteria capable of attacking other bacteria without harming human cells. "Bacteria eating bacteria. How cool is that?" asks Professor Robert Mitchell, the team leader. He and his colleagues are also developing a natural compound called violacein to tackle Staphylococcus, a group of around 30 different bacteria known to cause skin infections, pneumonia and blood poisoning. Some Staphylococcus bacteria such as MRSA (methicillin-resistant Staphylococcus aureus) are resistant to antibiotics, making infections harder to treat.

Violacein is a so-called 'bisindole': a metabolite produced by bacteria from the condensation of two molecules of tryptophan (an essential amino acid used in many organisms to ensure normal functioning and avoid illness and death). This compound is vibrant purple in colour and of interest to researchers for its anticancer, antifungal and antiviral properties. Researchers have discovered that it can stop bacteria from reproducing, and even kill the multidrug resistant bacterium Staphylococcus aureus, when used in the right doses. It also works well in conjunction with other existing antibiotics.

If you have long feared that using a "satnav" navigation system to get to your destination is making you worse at finding the way alone, research now suggests you may be right.

Scientists studying what satnavs do to the brain have found that people using them effectively switch off parts of the brain that would otherwise be utilized to simulate different routes and boost navigational skills.

Publishing the findings in the journal Nature Communications on Tuesday, the researchers said that when volunteers in an experiment navigated manually, their hippocampus and prefrontal cortex brain regions had spikes of activity. But these were not seen when the volunteers simply followed satnav instructions.

"When we have technology telling us which way to go ... these parts of the brain simply don't respond to the street network," said Hugo Spiers of University College London's (UCL)department of experimental psychology.

"In that sense our brain has switched off its interest in the streets around us."

More than 2 million procedures every year take place around the world to heal bone fractures and defects from trauma or disease, making bone the second most commonly transplanted tissue after blood. To help improve the outcomes of these surgeries, scientists have developed a new grafting material from sea urchin spines. They report their degradable bone scaffold, which they tested in animals, in the journal ACS Applied Materials & Interfaces.

Physicians have various approaches at hand to treat bone defects: Replacement material can come from a patient's own body, donated tissue, or a synthetic or naturally derived product. All of these methods, however, have limitations. For example, current bioceramics, such as hydroxyapatite, that have been used as scaffolds for bone repair tend to be weak and brittle, which can lead to pieces breaking off. These pieces can then move into adjacent soft tissue, causing inflammation. Recent studies have shown that biological materials, such as sea urchin spines, have promise as bone scaffolds because of their porosity and strength. Xing Zhang, Zheng Guo, Yue Zhu and colleagues wanted to test this idea in more detail.

Using a hydrothermal reaction, the researchers converted sea urchin spines to biodegradable magnesium-substituted tricalcium phosphate scaffolds while maintaining the spines' original interconnected, porous structure. Unlike hydroxyapatite, the scaffolds made from sea urchin spines could be cut and drilled to a specified shape and size. Testing on rabbits and beagles showed that bone cells and nutrients could flow through the pores and promote bone formation. Also, the scaffold degraded easily as it was replaced by the new growth. The researchers say their findings could inspire the design of new lightweight materials for repairing bones.

Scientists have discovered that a "breathtaking" flash of light occurs at the moment of conception.

For the first time, researchers from Northwestern University have now demonstrated that when a human sperm first meets an egg a bright zinc spark can be seen, not only a "remarkable" phenomenon but also one that might be a game-changer for in vitro fertilization.

"It was remarkable," said the study's co-author Professor Teresa Woodruff. "We discovered the zinc spark just five years ago in the mouse, and to see the zinc radiate out in a burst from each human egg was breathtaking. All of biology starts at the time of fertilization, yet we know next to nothing about the events that occur in the human."

The researchers say that the size of the flash of light provides valuable information about the health of the eggs. The brighter the flash, the more viable the egg, and thus the better option for in vitro fertilization, which has a high failure rate (around 50%) and often involves clinicians using imprecise means of testing or simply choosing whichever eggs they think appear to be most viable.

"This means if you can look at the zinc spark at the time of fertilization, you will know immediately which eggs are the good ones to transfer in in vitro fertilization," explained Woodruff. "It's a way of sorting egg quality in a way we've never been able to assess before."

A team of scientists has discovered that a law controlling the bizarre behavior of black holes out in space—is also true for cold helium atoms that can be studied in laboratories.

"It's called an entanglement area law," says Adrian Del Maestro, a physicist at the University of Vermont who co-led the research. That this law appears at both the vast scale of outer space and at the tiny scale of atoms, "is weird," Del Maestro says, "and it points to a deeper understanding of reality."

The new study was published March 13 in the journal Nature Physics—and it may be a step toward a long-sought quantum theory of gravity and new advances in quantum computing.

Land within major California seismic faults could sink by between 1.5 and 3 feet in a matter of seconds, causing catastrophic devastation, says a new study. It also shows that the Newport-Inglewood fault is more active than previously thought.

"It's not just a gradual sinking. This is boom — it would drop. It's very rapid sinking," Robert Leeper, lead author of a new study published in Nature, carried out with the help of the US Geological Survey, told the LA Times.

Leeper's team took 55 samples at the Seal Beach National Wildlife Refuge in southern Los Angeles, by submerging 20-feet pipes that collected samples of the sediment, initially looking for evidence for a prehistoric tsunami.

Instead, the team from Cal State Fullerton found an identical pattern, of living vegetation suddenly dropping and being buried underneath the ground. "We identified three of these buried layers composed of vegetation or sediment that used to be at the surface," said Leeper.

President Donald Trump has signed a bill authorizing $19.5 billion in funding for NASA, which includes an increased focus on deep space exploration and a new goal of a manned mission to Mars.

The NASA Transition Authorization Act of 2017, or S. 442, provides funding for fiscal year 2018, which begins October 1. It specifically appropriates money for NASA's deep space exploration, including the Space Launch System and the Orion spacecraft, as well as for the ongoing medical monitoring and treatment of astronauts. It builds on the current public-private partnership for space, with commercial companies transporting American astronauts to the International Space Station (ISS) and NASA focusing on deep space and the mission to Mars.

"For almost six decades, NASA's work has inspired millions and millions of Americans to imagine distant worlds and a better future right here on Earth. I'm delighted to sign this bill," Trump said. "With this legislation, we support NASA's scientists, engineers, astronauts and their pursuit of discovery. We support jobs. It's about jobs, also."

Researchers long believed that the cerebellum did little more than process our senses and control our muscles. New techniques to study the most densely packed neurons in our brains reveal that it may do much more.

Pity the cerebellum, tucked in the back of the brain mostly just keeping our muscles running smoothly. Its larger neighbor, the cerebrum, gets all the attention. It's the seat of intelligence, the home of thinking and planning. It's what separates humans from our less quick-witted ancestors. The cerebellum - which literally means "little brain" - is thought to just sit there helping us balance and breathe, like some kind of wee heating and ventilation system.

But maybe not for long. In a series of experiments published March 20 in Nature, Stanford researchers show that neurons within the cerebellum respond to and learn to anticipate rewards, a first step toward a much more exciting future for the cerebrum's largely overlooked little brother and one that could open up new avenues of research for neuroscientists interested in the roots of cognition.

Thanks to the discovery of a new material by University of Utah engineers, jewelry such as a ring and your body heat could generate enough electricity to power a body sensor, or a cooking pan could charge a cellphone in just a few hours.

The team, led by University of Utah materials science and engineering professor Ashutosh Tiwari, has found that a combination of the chemical elements calcium, cobalt and terbium can create an efficient, inexpensive and bio-friendly material that can generate electricity through a thermoelectric process involving heat and cold air.

Their findings were published in a new paper March 20 in the latest issue of Scientific Reports. The first author on the paper is University of Utah materials science and engineering postdoctoral researcher, Shrikant Saini.