Researchers from NIST and California Institute of Technology (Caltech) have demonstrated a new design for an atomic clock that is based on a chip-scale frequency comb, or a microcomb. The microcomb clock, featured in Optica, is the first demonstration of all-optical control of the microcomb, and its accurate conversion of optical frequencies to lower microwave frequencies.
Nearly all electronics require devices called oscillators that create precise frequencies. For...
At the nanoscale, where objects are measured in billionths of meters and events transpire in...
Deep below the Earth's surface lies a thick, rocky layer called the mantle, which makes up the majority of our planet's volume. For decades, scientists have known that most of the lower mantle is a silicate mineral with a perovskite structure that is stable under the high-pressure and high-temperature conditions found in this region.
Researchers are trying to develop solar-driven generators that can split water, yielding hydrogen gas that could be used as clean fuel. Such a device requires efficient light-absorbing materials that attract and hold sunlight to drive the chemical reactions involved in water splitting. Semiconductors are excellent light absorbers. However, these materials rust when submerged in the type of water solutions found in such systems.
Fancy Erector Set? Nope. The elaborate fractal structure shown at left is many, many times smaller than that and is certainly not child's play. It’s the latest example of a fractal nanotruss—nano because the structures are made up of members that are as thin as 5 nm; truss because they are carefully architected structures that might one day be used in structural engineering materials.
Supernovae are incredibly energetic, dynamic events. It’s easy to imagine that they are uncommon, but the universe is a big place and supernovae are actually fairly routine. The problem with observing supernovae is knowing just when and where one is occurring and being able to point a world-class telescope at it in the hours immediately afterward, when precious data about the supernova's progenitor star is available.
Caltech researchers have found a way to make measurements that go beyond the limits imposed by quantum physics. Today, we are capable of measuring the position of an object with unprecedented accuracy, but quantum physics and the Heisenberg uncertainty principle place fundamental limits on our ability to measure.
Caltech astronomers have taken unprecedented images of the intergalactic medium (IGM)—the diffuse gas that connects galaxies throughout the universe—with the Cosmic Web Imager, an instrument designed and built at Caltech. Until now, the structure of the IGM has mostly been a matter for theoretical speculation. However, with observations from the Cosmic Web Imager, astronomers are obtaining our first 3-D pictures of the IGM.
Huntington's disease is a grim diagnosis. A hereditary disorder with debilitating physical and cognitive symptoms, the disease usually robs adult patients of their ability to walk, balance and speak. More than 15 years ago, researchers revealed the disorder's likely cause—an abnormal version of the protein huntingtin; however, the mutant protein's mechanism is poorly understood, and the disease remains untreatable.
From far away, the top of a leaf looks like one seamless surface; however, up close, that smooth exterior is actually made up of a patchwork of cells in a variety of shapes and sizes. Interested in how these cells individually take on their own unique forms, a Caltech team sought to pinpoint the shape-controlling factors in pavement cells, which are puzzle-piece-shaped epithelial cells found on the leaves of flowering plants.
In 2005, NASA's Cassini spacecraft sent pictures back to Earth depicting an icy Saturnian moon spewing water vapor and ice from fractures, known as "tiger stripes," in its frozen surface. It was big news that tiny Enceladus was such an active place. Since then, scientists have hypothesized that a large reservoir of water lies beneath that icy surface, possibly fueling the plumes.
In biology, scientists typically conduct experiments first, and then develop mathematical or computer models afterward to show how the collected data fit with theory. In his work, Rob Phillips flips that practice on its head. The Caltech biophysicist tackles questions in cellular biology as a physicist would—by first formulating a model that can make predictions and then testing those predictions.
The human relationship with microbial life is complicated. At almost any supermarket, you can pick up both antibacterial soap and probiotic yogurt during the same shopping trip. Although there are types of bacteria that can make us sick, a California Institute of Technology team is most interested in the thousands of other bacteria, many already living inside our bodies, that actually keep us healthy.
Imagine that you are in a meeting with coworkers or at a gathering of friends. You pull out your cell phone to show a presentation or a video on YouTube. But you don't use the tiny screen; your phone projects a bright, clear image onto a wall or a big screen. Such a technology may be on its way, thanks to a new light-bending silicon chip developed by researchers at the California Institute of Technology.
Although liquid water covers a majority of Earth's surface, scientists are still searching for planets outside of our solar system that contain water. Researchers have used a new technique to analyze the gaseous atmospheres of such extrasolar planets and have made the first detection of water in the atmosphere of the Jupiter-mass planet orbiting the nearby star tau Boötis.
Engineers like to make things that work. And if one wants to make something work using nanoscale components, the size of proteins, antibodies and viruses, mimicking the behavior of cells is a good place to start since cells carry an enormous amount of information in a very tiny packet.
In the battle against infection, immune cells are the body's offense and defense. It has long been known that a population of blood stem cells that resides in the bone marrow generates all of these immune cells. But most scientists have believed that blood stem cells participate in battles against infection in a delayed way, replenishing immune cells on the front line only after they become depleted.
A new laser developed by a research group at Caltech holds the potential to increase by orders of magnitude the rate of data transmission in the optical-fiber network: the backbone of the Internet. The high-coherence new laser converts current to light using III-V material, but in a fundamental departure from S-DFB lasers, it stores the light in a layer of silicon, which does not absorb light.
Methane, a key greenhouse gas, has more than doubled in volume in Earth's atmosphere since 1750. Its increase is believed to be a leading contributor to climate change. But where is the methane coming from? Research by a California Institute of Technology atmospheric chemist suggests that losses of natural gas—our "cleanest" fossil fuel—into the atmosphere may be a larger source than previously recognized.
In 2011, biologists at Caltech demonstrated a highly effective method for delivering HIV-fighting antibodies to mice—a treatment that protected the mice from infection by a laboratory strain of HIV delivered intravenously. Now the researchers have shown that the same procedure is just as effective against a strain of HIV found in the real world, even when transmitted across mucosal surfaces.
We tend to be creatures of habit. In fact, the human brain has a learning system devoted to guiding us through routine, or habitual, behaviors. At the same time, the brain has a separate goal-directed system for the actions we undertake only after careful consideration of the consequences. We switch between the two systems as needed. But how does the brain know which system to give control to at any given moment? Enter The Arbitrator.
According to the National Institute of Mental Health, over 18% of American adults suffer from anxiety disorders. Previous studies of anxiety in the brain have focused on the amygdala, an area known to play a role in fear. But a team of researchers had a hunch that understanding a different brain area, the lateral septum (LS), could provide more clues into how the brain processes anxiety.
The human intestinal tract, or gut, is best known for its role in digestion. But this collection of organs also plays a prominent role in the immune system. In fact, it is one of the first parts of the body that is attacked in the early stages of an HIV infection. Knowing how the virus infects cells and accumulates in this area is critical to developing new therapies for the over 33 million people worldwide living with HIV.
In the Earth Surface Dynamics Lab at the California Institute of Technology the behavior of rivers is modeled through the use of artificial rivers—flumes—through which water can be pumped at varying rates over a variety of carefully graded sediments while drag force and acceleration are measured. The largest flume is a 12-m tilting version that can model many river conditions.
For decades, astrophysicists have encountered a puzzling contradiction: although many galactic-wind models—simulations of how matter is distributed in our universe—predict that the majority of the "normal" matter exists in stars at the center of galaxies, in actuality these stars account for less than 10% of the matter in the universe. A new set of simulations offer insight into this mismatch between the models and reality.
If you've ever slipped on a slimy wet rock at the beach, you have bacteria to thank. Those bacteria, nestled in a supportive extracellular matrix, form bacterial biofilms. For some marine organisms, these biofilms serve a vital purpose, flagging suitable homes for such organisms and actually aiding the transformation of larvae to adults. A new study is the first to describe a mechanism for this phenomenon.
Although researchers have determined the ages of rocks from other planetary bodies, the actual experiments have been done on Earth. Now, for the first time, researchers have successfully determined the age of a Martian rock with experiments performed on Mars. The work could not only help in understanding the geologic history of Mars but also aid in the search for evidence of ancient life on the planet.
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