Heavens

For the first time astronomers have detected gravitational waves from a merged, hyper-massive neutron star. The scientists, Maurice van Putten of Sejong University in South Korea, and Massimo della Valle of the Osservatorio Astronomico de Capodimonte in Italy, publish their results in Monthly Notices of the Royal Astronomical Society: Letters.

Gravitational waves were predicted by Albert Einstein in his General Theory of Relativity in 1915. The waves are disturbances in space time generated by rapidly moving masses, which propagate out from the source. By the time the waves reach the Earth, they are incredibly weak and their detection requires extremely sensitive equipment. It took scientists until 2016 to announce the first observation of gravitational waves using the Laser Interferometer Gravitational Wave Observatory (LIGO) detector.

Since that seminal result, gravitational waves have been detected on a further six occasions. One of these, GW170817, resulted from the merger of two stellar remnants known as neutron stars. These objects form after stars much more massive than the Sun explode as supernovae, leaving behind a core of material packed to extraordinary densities.

At the same time as the burst of gravitational waves from the merger, observatories detected emission in gamma rays, X-rays, ultraviolet, visible light, infrared and radio waves - an unprecedented observing campaign that confirmed the location and nature of the source.

The initial observations of GW170817 suggested that the two neutron stars merged into a black hole, an object with a gravitational field so powerful that not even light can travel quickly enough to escape its grasp. Van Putten and della Valle set out to check this, using a novel technique to analyse the data from LIGO and the Virgo gravitational wave detector sited in Italy.

Their detailed analysis shows the H1 and L1 detectors in LIGO, which are separated by more than 3,000 kilometres, simultaneously picked up a descending 'chirp' lasting around 5 seconds. Significantly, this chirp started between the end of the initial burst of gravitational waves and a subsequent burst of gamma rays. Its low frequency (less than 1 KHz, reducing to 49 Hz) suggests the merged object spun down to instead become a larger neutron star, rather than a black hole.

There are other objects like this, with their total mass matching known neutron star binary pairs. But van Putten and della Valle have now confirmed their origin.

Van Putten comments: "We're still very much in the pioneering era of gravitational wave astronomy. So it pays to look at data in detail. For us this really paid off, and we've been able to confirm that two neutron stars merged to form a larger one."

Gravitational wave astronomy, and eking out the data from every detection, will take another step forward next year, when the Japanese Kamioka Gravitational Wave Detector (KAGRA) comes online.

Some things are so complicated that it is completely impossible to precisely calculate them. This includes large quantum systems, which consist of many particles, particularly when they are not in an equilibrium state, but changing rapidly. Such examples include the wild particle inferno that occurs in particle accelerators when large atoms collide, or in the early universe, just after the Big Bang, when particles rapidly expanded and subsequently cooled.

At TU Wien and Heidelberg University, remarkable rules have been detected in the apparent chaos of disequilibrium processes. This indicates that such processes can be divided into universality classes. Systems belonging to the same class behave identically in many ways. This means that experiments can be carried out with quantum systems that are easy to handle, in order to obtain precise information about other systems that cannot be directly studied in the experiment. These findings have since been published in the journal 'Nature'.

Universal rules

"Universality classes are known from other areas of physics," says Prof. Jörg Schmiedmayer from the Institute of Atomic and Subatomic Physics at TU Wien. "When you study phase transitions, for example materials very close to the melting point, you can describe certain properties using formulas that are very universal, such as the relationship between the specific heat and the temperature." The microscopic details of the melting process do not matter. Very different materials can obey the same simple equations.

"It is however entirely astounding that universality of this kind can also be found in quantum systems that are far removed from an equilibrium state," says Jörg Schmiedmayer. "At first glance, you wouldn't expect this: why should a quantum system made up of many particles that are changing extremely rapidly obey any universal laws?" Nevertheless, theoretical work from Jürgen Berges and Thomas Gasenzer's groups from Heidelberg University predicted exactly that. These notable predictions have now been verified twice at the same time - at TU Wien and in Heidelberg.

The quick and the slow direction

The experiment in Prof. Schmiedmayer's group at the Vienna Center for Quantum Science and Technology (VCQ) at the Institute of Atomic and Subatomic Physics (TU Wien) is using a very special atom trap. On an atom chip, thousands of rubidium atoms can be trapped and cooled using electromagnetic fields. "In this process, we generate an atom cloud with a short and a long direction, similar to a cigar," explains Sebastian Erne, the lead author of the study.

Initially, the atoms move in all directions at the same speed. The atom trap can however be opened in the short (transverse) directions, meaning that those atoms that are moving particularly fast in this direction fly away. This leaves behind only atoms that have a relatively low speed in the transverse directions.

"The speed distribution in one direction is changed so quickly that during this time, the speed distribution in the other direction, along the longer axis of the cigar, virtually does not change at all," says Sebastian Erne. "As a result, we produce a state that is far from the thermal equilibrium." Collisions and interactions then lead to energy exchange between the atoms, which is referred to as 'thermalisation'.

"Our experiment demonstrates that the course of this thermalisation follows a universal law and is not dependent on any details," says Jörg Schmiedmayer. "Regardless of how we started the thermalisation, the transition can always be described with the same formula."

It was a similar story for the research team from Heidelberg. There too, they started out with an elongated atom cloud. However, the Heidelberg team did not study the speed but the spin (the intrinsic angular momentum) of the particles. They first controlled the spin directions of the atoms and then observed how these directions change over time due to interactions between the atoms.

This change can be described using the same formulas as the one from the other experiment: "In our case, the physical situation is quite different from that of the TU Wien experiment, but the dynamics also obey universal scaling laws," explains Maximilian Prüfer (Heidelberg), first author of Heidelberg publication. "We have found a process that also obeys the universality but belongs to a different universality class. This is great because it confirms our theories very convincingly and suggests that we really are on to something - a new, fundamental law, " says Markus Oberthaler (also Heidelberg).

Learning from one system about others

Universality upens up the possibility to obtain important information on quantum systems that are usually inaccessible in a laboratory. "Nobody can recreate the Big Bang in a laboratory, but if we know the universality class to which it belongs, we can look at other quantum systems in the same class and indirectly investigate universal properties during the Big Bang," explains Schmiedmayer. "Better understanding the behaviour of many-particle quantum systems that are far from equilibrium is one of the most pressing issues in physics today. Even with the best supercomputers, there's no chance of precisely calculating these events, and so our universality classes are a major opportunity to learn something new."

The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN)--operators of the world's largest particle physics lab--near Geneva, Switzerland, is said to be the largest particle accelerator in the world. The accelerator lies in a tunnel 27 kilometers in circumference, as deep as 175 meters beneath the French-Swiss border. This, by the way, has helped scientists uncover the Higgs boson, the last particle predicted by the Standard Model in 2012.

Following the discovery of Higgs, a primary scientific goal of high energy physicits has been to characterize the properties of this new particle and to discover oher high-energy physics phenomenon. As a result, there have been some rapid developments in high-energy particle accelerator technology to support high-energy physics research. However, the technologies used to date can only be improved and expanded at great expense. For this reason, making high-energy accelerators more affordable is urgently needed.

An international team of physicists, working on the Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) at CERN, reported that they have conducted a groundbreaking experiment demonstrating a new way of accelerating electrons to high energies -- one that could dramatically shrink the size of future particle accelerators and lower their costs. A paper describing this important result was published in Nature on August 29, 2018.

AWAKE is an international scientific collaboration, made up of engineers and scientists from 18 institutes, including CERN and the Max Planck Institute for Physics in Germany. A UNIST-based research group, led by Professor Moses Chung in the Department of Physics is also part of this AWAKE collaboration and made a number of important contributions to AWAKE. This includes the design of beamlines and the optimization of electron beam injection.

"AWAKE's technology will bring about a paridigm shift in the development of future high-energy particle accelerators, following LHC," says Professor Chung. "The latest achievement could enable engineers to drastically reduce the size of future particle accelerators, cutting down on the vast amounts of money normally required to build them." He adds, "The high-energy particle collisions these facilities produce enable physicists to probe the fundamental laws of nature, providing the basis for advancements in a huge variety of different fields."

Typically, particle physics experiments use oscillating electric fields, called radiofrequency cavities, and high-powered magnets to accelerate particles to high energies. But these experiments must grow quite large--they have to be, in order to accelerate particles with enough energy to properly study them.

As an alternative cost-cutting option to accelerate particles more efficiently, the wakefield accelerator has been suggested. Physicists send a beam of either electrons, protons, or a laser through a plasma. Free electrons in the plasma move toward the beam, but overshoot it, then come crashing back, creating a bubble structure behind the beam and intense electric fields. If you inject particles, like more electrons, into the wake, it can accelerate the injected particles in a shorter amount of time with an electric field 10 or more times stronger.

In the study, proton-driven plasma wakefield acceleration has been demonstrated for the first time. The strong electric fields, generated by a series of proton microbunches, were sampled with a bunch of electrons. These electrons were accelerated up to 2 GeV in approximately 10 m of plasma and measured using a magnetic spectrometer. This technique has the potential to accelerate electrons to the TeV scale in a single accelerating stage.

Although still in the early stages of its programme, the AWAKE collaboration has taken an important step on the way to realising new high energy particle physics experiments.

About 15 percent of breast cancers are classified as triple-negative, lacking receptors for estrogen, progesterone, and Her2. These cancers do not respond to targeted hormonal therapies, and they tend to be particularly aggressive, often resisting systemic chemotherapy and metastasizing to other tissues.

Researchers had observed that triple-negative breast cancer (TNBC) patients who had higher numbers of a type of immune cell called myeloid-derived immunosuppressor cells (MDSCs) in their bloodstream had poorer outcomes. But until now it wasn't clear how MDSCs are recruited to the primary breast tumor and how they contributed to its progression and spread.

A new report led by the University of Pennsylvania School of Veterinary Medicine's Rumela Chakrabarti, an assistant professor of biomedical sciences, and Sushil Kumar, a postdoctoral researcher in Chakrabarti's lab, fills in crucial details about the connection between MDSCs and aggressive disease. In the Journal of Clinical Investigation, Chakrabarti, Kumar, and colleagues identify a protein, deltaNp63, on tumor cells that directs MDSCs to the tumor and metastatic sites, where they promote tumor growth and metastasis. Blocking either this protein or the MDSCs themselves reduced tumor growth and metastasis in a mouse model of TNBC.

"We're excited because we think our findings could make a big difference for triple-negative breast cancer patients," says Chakrabarti. "Not only can deltaNp63 be used as a biomarker to help personalize treatment regimens, but targeting it may also provide an additive treatment for triple-negative breast cancer, in addition to chemotherapy and radiation."

Earlier studies by Chakrabarti and colleagues showed that increased levels of deltaNp63 were linked with breast cancer initiation. In the current work, her team found deltaNp3 was elevated in samples of TNBC patient's primary tumors, as were numbers of MDSCs.

Intrigued, Chakrabarti, Kumar, and their coauthors used multiple mouse models and tissue transplants to see how manipulating the level of deltaNp63 affected the behavior of cancer, and they found lower levels corresponded with less metastasis to distant tissues. In addition, knocking down levels of deltaNp63 made the tumors much less aggressive, and it reduced numbers of MDSCs recruited to the tumor but not other immune cell types.

The researchers confirmed the relationship between deltaNp63 and MDSCs, showing that blocking two signaling molecules, CXCL2 and CCL22, activated by the protein reduced metastasis and blood-vessel growth associated with tumor growth, while increasing levels of these signaling molecules, caused MDSCs to boost the secretion of pro-tumor growth factors.

"How are the immune cells helping cancer cells?" Chakrabarti says. "It seems they are helping cancer stem cells grow faster." Cancer stem cells can give rise to all the other cells in a tumor, just as normal stem cells can differentiate into other cell types. These cells are resistant to chemotherapy and radiation, which may explain why triple-negative breast cancer patients don't respond to therapy, Chakrabarti says. "We propose that it's these immune cells [MDSCs] that are nurturing the cancer stem cells."

The research team used small molecules to inhibit CXCL2 and CCL22 in human TNBC cell lines as well as in a mouse model of TNBC, a blockade that significant reduced levels of MDSCs moving to the primary tumor and that substantially lowered signs of metastasis.

Chakrabarti believes that a drug that zeroes in on MDSCs could fill a gap in triple-negative breast cancer treatment. Offered in conjunction with more general therapies such as chemotherapy and radiation, it may give patients an option that is more tailored to their cancer. Her lab is now working with animal models and cell lines derived from breast-cancer patients to test this combination approach to treatment.

Taking advantage of observations from the Hubble Space Telescope, researchers provide evidence of what could be the first exomoon - a moon orbiting a planet outside our solar system. While the authors were rigorous in their evaluations, they caution that their results must be confirmed by subsequent work. Recently, NASA's Kepler space telescope surveyed for moons in a sample of 284 transiting planets - planets that pass between a star and an observer, resulting in a momentary dimming of the star's light. The data suggested that a Jupiter-sized planet, Kepler-1625b, may be orbited by an exomoon. Based on this promising evidence, Alex Teachey and David M. Kipping requested and were awarded 40 hours of time to observe the transits of this planet using the Hubble Space Telescope (HST), which is about four times more precise than Kepler. Studying the transits helped the researchers look for two signals that would be suggestive of an exomoon: a reduction in the star's brightness as a potential exomoon passed in front, and the gravitational effects such a moon would have on Kepler-1625b - for example, in altering its transit start time. Both signals show up in the transit shape. About 3.5 hours after Kepler-1625b's transit completed, HST recorded a second smaller decrease in the star's brightness, a dimming indicative of a moon "trailing the planet like a dog following its owner on a leash," Kipping said. To better confirm the likelihood of an exomoon, further analyses of the HST observations were needed, as was use of refined Kepler photometry data, say the authors. This is because any model of a moon must account for every transit event that has been observed (here, that included transits already observed by Kepler). The researchers' investigations showed that the HST-recorded transit of Kepler-1625b occurred nearly 80 minutes earlier than expected, a pattern suggesting the presence of transit timing variations, or TTVs, which are among the first proposed methods to confirm the presence of exomoons. The researchers note that in principle this anomaly could be caused by the gravitational pull of a hypothetical second planet in the system, although Kepler found no evidence for additional planets around the star during its four-year mission. While the authors caution that their results must be confirmed by subsequent studies, the moon of Kepler-1625b ultimately could be the first confirmed exomoon.

A newly discovered fossil suggests that large, flowering trees grew in North America by the Turonian age, showing that these large trees were part of the forest canopies there nearly 15 million years earlier than previously thought. Researchers from Adelphi University and the Burpee Museum of Natural History found the fossil in the Mancos Shale Formation in Utah, in ancient delta deposits formed during a poorly understood interval in the North American fossil record.

"These discoveries add much more detail to our picture of the landscape during the Turonian period than we had previously," says Michael D'Emic, assistant professor of biology at Adelphi, who organized the study. "Since Darwin, the evolution of flowering plants has been a topic of debate for paleontologists because of their cryptic fossil record. Our paper shows that even today it is possible for a single fossil specimen to change a lot about what we know about the early evolution of the group.

"Understanding the past is the key to managing the future," D'Emic added. "Learning how environments evolved and changed in the past teaches us how to better prepare for future environmental change."

Aside from the large petrified log, the team reports fossilized foliage from ferns, conifers and angiosperms, which confirm that there was forest or woodland vegetation 90 million years ago in the area, covering a large delta extending into the sea. The team also reports the first turtle and crocodile remains from this geologic layer, as well as part of the pelvis of a duck-billed dinosaur; previously, the only known vertebrate remains found were shark teeth, two short dinosaur trackways, and a fragmentary pterosaur.

"Until now most of what we knew about plants from the Ferron Sandstone came from fossil pollen and spores," says Nathan Jud, co-author and assistant professor of biology at William Jewell College. "The discovery of fossil wood and leaves allows us to develop a more complete picture of the flora."

New 3D maps of water distribution during cellular membrane fusion are accelerating scientific understanding of cell development, which could lead to new treatments for diseases associated with cell fusion. Using neutron diffraction at the Department of Energy's Oak Ridge National Laboratory, researchers have made the first direct observations of water in lipid bilayers used to model cell membrane fusion.

The research, published in Journal of Physical Chemistry Letters, could provide new insights into diseases in which normal cell fusion is disrupted, such as Albers-Schönberg disease (osteopetrosis), help facilitate the development of fusion-based cell therapies for degenerative diseases, and lead to treatments that prevent cell-to-cell fusion between cancer cells and non-cancer cells.

When two cells combine during fertilization, or a membrane-bound vesicle fuses during viral entry, neuron signaling, placental development and many other physiological functions, the semi-permeable membrane bilayers between the fusing partners must be merged to exchange their internal contents. As the two membranes approach each other, hydration forces increase exponentially, which requires a significant amount of energy for the membranes to overcome. Mapping the distribution of water molecules is key to understanding the fusion process.

Researchers used the small-angle neutron scattering (EQ-SANS) instrument at ORNL's Spallation Neutron Source and the biological small-angle neutron scattering (Bio-SANS) instrument at the High Flux Isotope Reactor, both of which can probe structures as small as a few nanometers in size.

"We used neutrons to probe our samples, because water typically can't be seen by x-rays, and because other imaging techniques can't accurately capture the extremely rapid and dynamic process of cellular fusion," said Durgesh K. Rai, co-author and now a post-doctoral associate at the Cornell High Energy Synchrotron Source at Cornell University. "Additionally, the cold, lower-energy neutrons at EQ-SANS and Bio-SANS won't cause radiation damage or introduce radicals that can interfere with lipid chemistry, as x-rays can do."

The researchers' water density map indicates the water dissociates from the lipid surfaces in the initial lamellar, or layered, phase. In the intermediate fusion phase, known as hemifusion, the water is significantly reduced and squeezed into pockets around a stalk--a highly curved lipid "bridge" connecting two membranes before fusion fully occurs.

"For the neutron scattering experiments, we replaced some of the water's hydrogen atoms with deuterium atoms, which helped the neutrons observe the water molecules during membrane fusion," said Shuo Qian, the study's corresponding author and a neutron scattering scientist at ORNL. "The information we obtained could help in future studies of membrane-acting drugs, membrane-associated proteins, and peptides in a membrane complex."

Astronomers from the Department of Physics at the University of Tokyo discovered a dense disk of material around a young star, which may be a precursor to a planetary system. Their research could vastly improve models of how solar systems form, which would tell us more about our own place in the cosmos.

Early in 2017, Assistant Professor Yoko Oya gave graduate student Yuki Okoda some recent complex data on a nearby star with which she could begin her Ph.D. Little did she realize that what she would find could unlock not only the secrets of how planets form but possibly her career as a professional astronomer.

The star in question (only known by its catalog number IRAS 15398-3359) is small, young and relatively cool for a star. It's diminutive stature means the weak light it shines can't even reach us through a cloud of gas and dust that surrounds it. But this doesn't stop inquisitive minds from exploring the unknown.

In 2013, Oya and her collaborators used the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to observe the star in submillimeter wavelengths, as that kind of light can penetrate the dust cloud - for reference, red light is around 700 nanometers. A painstaking analysis revealed some interesting nebulous structures, despite the images they worked from being difficult to comprehend.

"The greatest academic challenge I've faced was trying to make sense of grainy images. It's extremely difficult to know exactly what you're really looking at." says Okoda. "But I felt compelled to explore the nature of the structures Dr. Oya had seen with ALMA, so I came up with a model to explain them." The model she produced came as a surprise to Okoda and her colleagues, but it fit the data perfectly. It describes a dense disk of material that consists of gas and dust from the cloud that surrounds the star. This has never before been seen around such a young star.

The disk is a precursor to a protoplanetary disk, which is far denser still and eventually becomes a planetary system in orbit around a star.

"We can't say for sure this particular disk will coalesce into a new planetary system," explains Oya. "The dust cloud may be pushed away by stellar winds or it might all fall into the star itself, feeding it in the process. What's exciting is how quickly this might happen."

The star is small at around 0.7 percent the mass of our sun, based on observations of the mass of the surrounding cloud. It could grow to as large as 20 percent in just a few tens of thousands of years, a blink of the eye on the cosmic scale.

"I hope our observations and models will enhance knowledge of how solar systems form," says Okoda. "My research interests involve young protostellar objects, and the implication that protoplanetary disks could form earlier than expected really excites me."

Okoda began this project a year-and-a-half ago to hone her skills as an astronomer, but mirroring the young star she observed, the practice evolved quickly and became a full research project, which will hopefully earn her a Ph.D. from the University of Tokyo.

The observations and resultant model were only possible thanks to advancements in radio astronomy with observatories such as ALMA. The team was lucky that the plane of the disk is level with our own solar system as this means the starlight ALMA sees passes through enough of the gas and dust to divulge important characteristics of it.

"We were also lucky to be given time with ALMA to carry out our observations. Only about 20 percent of applications actually go ahead," explains Oya. "With highly specialized astronomical instruments, there is much competition for time. My hope is our success will inspire a new generation of astronomers in Japan to reach for the stars."

A team of scientists led by researchers from the University of Hawai'i at Mānoa School of Ocean and Earth Science and Technology (SOEST) found the first direct evidence for the surface exposed water ice in permanently shaded regions (PSRs) of the Moon.

"We found that the distribution of ice on the lunar surface is very patchy, which is very different from other planetary bodies such as Mercury and Ceres where the ice is relatively pure and abundant," said lead author Shuai Li, a postdoctoral researcher at the Hawai'i Institute of Geophysics and Planetology (HIGP) in SOEST. "The spectral features of our detected ice suggest that they were formed by slow condensation from a vapor phase either due to impact or water migration from space."

The team analyzed data acquired by the Moon Mineralogy Mapper (M3) onboard India's Chandrayaan-1 mission launched in 2008. They found absorption features in the M3 data that were similar to those of pure water ice measured in the laboratory. Their findings were further validated with other datasets such as the data acquired by the Lunar Orbiter Laser Altimeter (LOLA), The Lyman-Alpha Mapping Project (LAMP), and the Diviner instrument onboard America's Lunar Reconnaissance Orbiter (LRO) mission.
 

Before this research, there was no direct evidence of water ice on the lunar surface. Usually, M3 measures reflected light from the illuminated regions on the Moon. At PSRs, there is no direct sunlight reflected so M3 can only measure scattered light in those areas. Without an atmosphere, light bouncing around the surface of the Moon is scattered very weakly, producing a weak signal for the research team to work with.

"This was a really surprising finding," said Li. "While I was interested to see what I could find in the M3 data from PSRs, I did not have any hope to see ice features when I started this project. I was astounded when I looked closer and found such meaningful spectral features in the measurements."

"The patchy distribution and smaller abundance of ice on the Moon compared with other planetary bodies suggest that the delivery, formation, and retention processes of water ice on the Moon are very unique," said Paul Lucey, professor at HIGP and co-author on the study.  

"Given that the Moon is our nearest planetary neighbor, understanding the processes which led to water ice on the Moon provides clues to understand the origin of water on Earth and throughout the solar system," said Li. "A future Moon mission is needed to examine the whole lunar PSRs to map out all water ices and understand the processes which led to water on the Moon. This work provides a roadmap for future exploration of the Moon, particularly the potential of water ice as a resource."

They combined auxin-inducible "protein knockdown" with a synthetic antibody to not only observe fluorescent proteins in living cells but also to rapidly remove them in a temporally controlled manner.

Perhaps the most important basic component of all cells are proteins that perform a wide variety of functions in cells and tissues. In order to clarify the physiological roles of proteins, they are often linked to a green fluorescent protein (GFP) via targeted genetic manipulation, which makes them visible under the microscope. The observation of such GFP-linked proteins in living cells allows initial conclusions about the function of the protein. However, the exact function of a protein can often only be determined when the protein is removed and the resulting consequences become visible in cells, tissues or model organisms.

This is usually achieved by knockout of the protein on the genetic level. However, the functions of essential proteins cannot be examined in this way, because the cell or the model organism would not be viable. Instead, an approach is needed that allows removing proteins from cells only at a specific time. Such a targeted temporary degradation of proteins occurs naturally in plants and is mediated by the plant hormone auxin. After genetic manipulation, the underlying mechanism can also be applied to animal and human cells.

Dr. Jörg Mansfeld's research group has developed a novel AID-nanobody in order to not only observe GFP-linked proteins in living cells, but to also rapidly degrade them in a targeted manner for functional analysis. For this purpose, the auxin recognition sequence (AID) was linked to a GFP recognizing antibody that is structurally-related to camelid antibodies (nanobody). It could be shown that this so-called AID-nanobody allows the almost complete degradation of GFP-linked proteins in human cell culture after the addition of auxin. The possibility to follow the degradation of the protein "live" under the microscope makes functional analysis much easier.

In collaboration with the research group of Dr. Caren Norden, it was shown that the AID-nanobody can also be successfully used in the model organism zebrafish. Using the AID-nanobody in zebrafish demonstrated for the first time that an auxin-mediated protein knockdown can also be implemented in a complex vertebrate model.

"Our work is an excellent example of biotechnology, in which different naturally occurring principles such as fluorescent GFP from algae, auxin-dependent protein degradation from plants and the nanobody from camelids are combined to answer previously inaccessible research questions," said Dr. Katrin Daniel from the Mansfeld Lab, commenting on the results of the research project.

The successful work highlights the synergies that can be achieved, when groups from different research institutes at the Dresden Science Campus work closely together.

Astronomers have identified some of the earliest galaxies in the Universe.

The team from the Institute for Computational Cosmology at Durham University and the Harvard-Smithsonian Center for Astrophysics, has found evidence that the faintest satellite galaxies orbiting our own Milky Way galaxy are amongst the very first galaxies that formed in our Universe.

Scientists working on this research have described the finding as "hugely exciting" explaining that that finding some of the Universe's earliest galaxies orbiting the Milky Way is "equivalent to finding the remains of the first humans that inhabited the Earth."

The research group's findings suggest that galaxies including Segue-1, Bootes I, Tucana II and Ursa Major I are in fact some of the first galaxies ever formed, thought to be over 13 billion years old.

When the Universe was about 380,000 years old, the very first atoms formed. These were hydrogen atoms, the simplest element in the periodic table. These atoms collected into clouds and began to cool gradually and settle into the small clumps or "halos" of dark matter that emerged from the Big Bang.

This cooling phase, known as the "Cosmic dark ages", lasted about 100 million years. Eventually, the gas that had cooled inside the halos became unstable and began to form stars - these objects are the very first galaxies ever to have formed.

With the formation of the first galaxies, the Universe burst into light, bringing the cosmic dark ages to an end.

Dr Sownak Bose, at Harvard-Smithsonian Center for Astrophysics, working with Dr Alis Deason and Professor Carlos Frenk at Durham University's ICC, identified two populations of satellite galaxies orbiting the Milky Way.

The first was a very faint population consisting of the galaxies that formed during the "cosmic dark ages". The second was a slightly brighter population consisting of galaxies that formed hundreds of millions of years later, once the hydrogen that had been ionized by the intense ultraviolet radiation emitted by the first stars was able to cool into more massive dark matter halos.

Remarkably, the team found that a model of galaxy formation that they had developed previously agreed perfectly with the data, allowing them to infer the formation times of the satellite galaxies.

Their findings are published in the Astrophysical Journal.

Professor Carlos Frenk, Director of Durham University's Institute for Computational Cosmology, said: "Finding some of the very first galaxies that formed in our Universe orbiting in the Milky Way's own backyard is the astronomical equivalent of finding the remains of the first humans that inhabited the Earth. It is hugely exciting.

"Our finding supports the current model for the evolution of our Universe, the 'Lambda-cold-dark-matter model' in which the elementary particles that make up the dark matter drive cosmic evolution."

The intense ultraviolet radiation emitted by the first galaxies destroyed the remaining hydrogen atoms by ionizing them (knocking out their electrons), making it difficult for this gas to cool and form new stars.

The process of galaxy formation ground to a halt and no new galaxies were able to form for the next billion years or so.

Eventually, the halos of dark matter became so massive that even ionized gas was able to cool. Galaxy formation resumed, culminating in the formation of spectacular bright galaxies like our own Milky Way.

Dr Sownak Bose, who was a PhD student at the ICC when this work began and is now a research fellow at the Harvard-Smithsonian Center for Astrophysics, said: "A nice aspect of this work is that it highlights the complementarity between the predictions of a theoretical model and real data.

"A decade ago, the faintest galaxies in the vicinity of the Milky Way would have gone under the radar. With the increasing sensitivity of present and future galaxy censuses, a whole new trove of the tiniest galaxies has come into the light, allowing us to test theoretical models in new regimes."

Dr Alis Deason, who is a Royal Society University Research Fellow at the ICC, Durham University, said: "This is a wonderful example of how observations of the tiniest dwarf galaxies residing in our own Milky Way can be used to learn about the early Universe."

Washington, DC--Blue diamonds--like the world-famous Hope Diamond at the National Museum of Natural History--formed up to four times deeper in the Earth's mantle than most other diamonds, according to new work published on the cover of Nature.

"These so-called type IIb diamonds are tremendously valuable, making them hard to get access to for scientific research purposes," explained lead author Evan Smith of the Gemological Institute of America, adding, "and it is very rare to find one that contains inclusions, which are tiny mineral crystals trapped inside the diamond."

Inclusions are remnants of the minerals from the rock in which the diamond crystallized and can tell scientists about the conditions under which it formed.

Type IIb diamonds owe their blue color to the element boron, an element that is mostly found on the Earth's surface. But analysis of the trapped mineral grains in 46 blue diamonds examined over two years indicate that they crystallized in rocks that only exist under the extreme pressure and temperature conditions of the Earth's lower mantle.

The research group--which included Carnegie's Steven Shirey, Emma Bullock, and Jianhua Wang--determined that blue diamonds form at least as deep as the transition zone between the upper and lower mantle--or between 410 and 660 kilometers below the surface. Several of the samples even showed clear evidence that they came from deeper than 660 kilometers, meaning they originated in the lower mantle. By contrast, most other gem diamonds come up from between 150 and 200 kilometers.

So how did the boron get down there if it is an element known for residing predominately in the shallow crust?

According to the hypothesis put forth by the research group, it came from seafloor that was conveyed down into the Earth's mantle when one tectonic plate slid beneath another--a process known as subduction.

The new study proposes that boron from the Earth's surface was incorporated into water-rich minerals like serpentine, which crystallized during geochemical reactions between seawater and the rocks of the oceanic plate. This reaction between rock and water is a process called serpentinization and can extend deep into the seafloor, even into the oceanic plate's mantle portion.

The group's discovery reveals that the water-bearing minerals travel far deeper into the mantle than previously thought, which indicates the possibility of a super-deep hydrological cycle.

"Most previous studies of super-deep diamonds had been carried out on diamonds of low quality," Shirey said. "But between our 2016 finding that the world's biggest and most-valuable colorless diamonds formed from metallic liquid deep inside Earth's mantle and this new discovery that blue diamonds also have super-deep origins, we now know that the finest gem-quality diamonds come from the farthest down in our planet."

Providing resolution to a decades-long debate over whether liquid water is present on Mars, researchers using radar to probe the planet's polar ice caps have detected a lake of liquid water under the Martian ice. It stretches 20 kilometers across, they say. The detection was made using the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on the Mars Express spacecraft. MARSIS sends radar pulses that penetrate the surface and ice caps of the planet, then measures how the radio waves propagate and reflect back to the spacecraft. Reflections off sub-surface features provide scientists with information about what lies beneath the surface. Between May 2012 and December 2015, Roberto Orosei and colleagues used MARSIS to survey a region called Planum Australe, located in the southern ice cap of Mars. They obtained 29 sets of radar samplings, mapping out an area exhibiting a very sharp change in its associated radar signal, about 1.5 kilometers below the surface of the ice and extending sideways about 20 kilometers. The radar profile of this area is similar to that of lakes of liquid water found beneath the Antarctic and Greenland ice sheets on Earth, suggesting that there is a subglacial lake at this location on Mars. Although the temperature is expected to be below the freezing point of pure water, Orosei et al. note that dissolved salts of magnesium, calcium, and sodium - known to be present in Martian rocks - could be dissolved in the water to form a brine. Together with the pressure of the overlying ice, this lowers the melting point, allowing the lake to remain liquid, as happens on Earth. Anja Diez compares the subglacial lake on Mars to such lakes under Earth's ice sheets, in an accompanying Perspective.