4,500-Year-Old Boat Found Near Pyramids

A unique ancient funerary boat has been unearthed near the Abusir pyramids, Egypt’s Antiquities Minister said in a statement.

The vessel dates to about 2550 B.C. and was discovered by archaeologists excavating a large mastaba, or ancient tomb, in a cemetery of the Old Kingdom officials in Abusir, south of the Giza plateau.

The 59-foot-long boat was found in the area south of the mud-brick tomb by a team of the Czech Institute of Archaeology at Charles University in Prague, led by excavation director Miroslav Bárta.

Covered with the wind-blown sand, the 4,500-year-old remains of the wooden vessel were lying on a bed of stone with ropes and wooden components still in their original position.

The wooden planks, joined with wooden pegs, were found intact. The desert sand preserved the plant fibers that covered the planking seams, while some of the ropes that bound the boat together were also found in their original position with all their details intact.

“It is by all means a remarkable discovery. The careful excavation and recording of the Abusir boat will make a considerable contribution to our understanding of ancient Egyptian watercraft and their place in funerary cult. And where there is one boat, there very well may be more,” Bárta said.

The exact meaning of ancient Egyptian funerary boats is not certain. According to some scholars they were intended as solar barques, used during the journey of the owner through the underworld. Others argue they were simply funerary offerings to be used by the deceased in the afterlife.

The Old Kingdom kings often had several boats buried within their pyramid complexes, but most of the pits have been found empty of any timber, or with little more than patterns of brown dust.

The only exception were the two boats of Khufu, the pharaoh who built the Great Pyramid at Giza. Found in a dismantled state, they are in the process of reconstruction.

The Abusir boat is the first vessel of significant dimensions from the Old Kingdom that has been found in a non-royal context, the archaeologists said.

“This is a highly unusual discovery since boats of such a size and construction were, during this period, reserved solely for top members of the society, who usually belonged to the royal family,” Bárta said.

Although the boat is located almost 40 feet south of the mastaba, its orientation, length, and the pottery collected from its interior, make a clear connection between the structure and the vessel.

A stone bowl discovered in one of the mastaba underground chambers bore the name of king Huni, the last pharaoh of the Third dynasty, thus dating the tomb to that time.

Read more at Discovery News

The Moon's Gravity Alters Rainfall on Earth

When the moon is high overhead at night, its gravity actually can reduce the amount of rainfall very slightly, new research reveals.

In an article for Geophysical Research Letters, University of Washington scientists Tsubasa Kohyama and John M. Wallace report that the moon causes the Earth’s atmosphere to bulge toward it. That causes the pressure, or weight of the atmosphere, on that side of the planet to go up, which in turn increases the temperature of air below.

Since warmer air can hold more moisture, the same parcels of air are now farther from their maximum moisture capacity, resulting in a slight dip in rainfall.

The researchers studied 15 years of data collected by NASA and the Japan Aerospace Exploration Agency’s Tropical Rainfall Measuring Mission satellite from 1998 to 2012. It proved that the rain is reduced by an amount that is measurable, though imperceptible to humans — a change of about 1 percent in the total rainfall variation.

“As far as I know, this is the first study to convincingly connect the tidal force of the moon with rainfall,” said Tsubasa Kohyama, a doctoral student in atmospheric sciences.

While the effect isn’t going to affect agriculture or alter weather forecasts, the knowledge is potentially beneficial to climate researchers, who can use it to test the physics behind their climate models.

The effect of the moon’s position on air pressure on Earth was first detected back in 1847, and researchers showed in 1932 that the moon could affect air temperature as well. A 2014 study by the same University of Washington researchers confirmed that air pressure on Earth varies with the position of the moon.

Wallace plans to conduct future studies to see whether certain types of rain storms, such as heavy downpours, are more susceptible to the moon’s position, and whether the moon has any effect on the frequency of storms.

From Discovery News

Night Falls on Pluto's Largest Moon Charon

Pluto's largest moon, Charon, is cloaked in darkness, with just a tiny sliver lit up by the distant sun, in a newly released photo.

NASA's New Horizons spacecraft captured the image on July 17, 2015, three days after the probe's historic flyby of Pluto. That close encounter brought New Horizons within just 7,800 miles (12,550 kilometers) of Pluto's surface; the night-side view of Charon, on the other hand, was taken from a distance of 1.9 million miles (3.1 million km), NASA officials said.

"Charon's nighttime landscapes are still faintly visible by light softly reflected off Pluto, just as 'Earthshine' lights up a new moon each month," agency officials wrote in a description of the image, which was released Friday (Jan. 22).

"Scientists on the New Horizons team are using this and similar images to map portions of Charon otherwise not visible during the flyby," the officials added. "This includes Charon's south pole — toward the top of this image — which entered polar night in 1989 and will not see sunlight again until 2107. Charon's polar temperatures drop to near absolute zero during this long winter."

At 753 miles (1,207 km) in diameter, Charon is more than half as wide as Pluto itself. The dwarf planet's other four moons — Nix, Hydra, Kerberos and Styx — are all tiny by comparison. For example, Nix and Hydra measure just 33 miles (54 km) and 27 miles (43 km), respectively, in their longest directions, while Styx and Kerberos are even smaller.

The $720 million New Horizons mission launched a decade ago, in January 2006. The probe is currently zooming toward a potential January 2019 flyby of a small object called 2014 MU69, which lies about 1 billion miles (1.6 billion km) beyond Pluto.

New Horizons will study 2014 MU69 up close, if NASA approves and funds a proposed extended mission. The spacecraft is also still beaming home the data and images it collected during the July 2015 flyby; this relay work should be done by this coming autumn, mission team members have said.

From Discovery News

Switching light with a silver atom

The quantity of data exchanged via communications networks around the globe is growing at a breathtaking rate. The volume of data for wired and mobile communications is currently increasing by 23% and 57% respectively every year. It is impossible to predict when this growth will end. This also means that all network components must constantly be made more efficient.

These components include so-called modulators, which convert the information that is originally available in electrical form into optical signals. Modulators are therefore nothing more than fast electrical switches that turn a laser signal on or off at the frequency of the incoming electrical signals. Modulators are installed in data centres in their thousands. However, they all have the disadvantage of being quite large. Measuring a few centimetres across, they take up a great deal of space when used in large numbers.

From micromodulators to nanomodulators

Six months ago, a working group led by Jürg Leuthold, Professor of Photonics and Communications already succeeded in proving that the technology could be made smaller and more energy-efficient. As part of that work, the researchers presented a micromodulator measuring just 10 micrometres across -- or 10,000 times smaller than modulators in commercial use.

Leuthold and his colleagues have now taken this to the next level by developing the world's smallest optical modulator. And this is probably as small as it can get: the component operates at the level of individual atoms. The footprint has therefore been further reduced by a factor of 1,000 if you include the switch together with the light guides. However, the switch itself is even smaller, with a size measured on the atomic scale. The team's latest development was recently presented in the journal Nano Letters.

In fact, the modulator is significantly smaller than the wavelength of light used in the system. In telecommunications, optical signals are transmitted using laser light with a wavelength of 1.55 micrometres. Normally, an optical device can not be smaller than the wavelength it should process. "Until recently, even I thought it was impossible for us to undercut this limit," stresses Leuthold.

New structure

But his senior scientist Alexandros Emboras proved the laws of optics wrong by successfully reconfiguring the construction of a modulator. This construction made it possible to penetrate the order of magnitude of individual atoms, even though the researchers were using light with a "standard wavelength."

Emboras's modulator consists of two tiny pads, one made of silver and the other of platinum, on top of an optical waveguide made of silicon. The two pads are arranged alongside each other at a distance of just a few nanometres, with a small bulge on the silver pad protruding into the gap and almost touching the platinum pad.

Short circuit thanks to a silver atom

And here's how the modulator works: light entering from an optical fibre is guided to the entrance of the gap by the optical waveguide. Above the metallic surface, the light turns into a surface plasmon. A plasmon occurs when light transfers energy to electrons in the outermost atomic layer of the metal surface, causing the electrons to oscillate at the frequency of the incident light. These electron oscillations have a far smaller diameter than the ray of light itself. This allows them to enter the gap and pass through the bottleneck. On the other side of the gap, the electron oscillations can be converted back into optical signals.

If a voltage is now applied to the silver pad, a single silver atom or, at most, a few silver atoms move towards the tip of the point and position themselves at the end of it. This creates a short circuit between the silver and platinum pads, so that electrical current flows between them. This closes the loophole for the plasmon; the switch flips and the state changes from "on" to "off" or vice versa. As soon as the voltage falls below a certain threshold again, a silver atom moves back. The gap opens, the plasmon flows, and the switch is "on" again. This process can be repeated millions of times.

ETH Professor Mathieu Luisier, who participated in this study, simulated the system using a high-performance computer at the CSCS in Lugano. This allowed him to confirm that the short circuit at the tip of the silver point is brought about by a single atom.

A truly digital signal

As the plasmon has no other options than to pass through the bottleneck either completely or not at all, this produces a truly digital signal -- a one or a zero. "This allows us to create a digital switch, as with a transistor. We have been looking for a solution like this for a long time," summarises Leuthold.

As yet, the modulator is not ready for series production. Although it has the advantage of operating at room temperature, unlike other devices that work using quantum effects at this order of magnitude, it still remains very slow for a modulator: so far, it only works for switching frequencies in the megahertz range or below. The ETH researchers want to fine-tune it for frequencies in the gigahertz to terahertz range.

Read more at Science Daily

Bright sparks shed new light on the dark matter riddle

The origin of matter in the universe has puzzled physicists for generations. Today, we know that matter only accounts for 5% of our universe; another 25% is constituted of dark matter. And the remaining 70% is made up of dark energy. Dark matter itself represents an unsolved riddle.

Physicists believe that such dark matter is composed of (as yet undefined) elementary particles that stick together thanks to gravitational force. In a study recently published in EPJ C, scientists from the CRESST-II research project use the so-called phonon-light technique to detect dark matter. They are the first to use a detection probe that operates with such a low trigger threshold, which yields suitable sensitivity levels to uncover the as-yet elusive particles responsible for dark matter.

Until quite recently, the so-called WIMP -- Weakly Interacting Massive Particle -- was the preferred candidate for a new elementary particle to explain dark matter. However, the asymmetric dark matter particle models have attracted more and more interest in the past few years. The experimental detection is no different from the scattering of two billiard balls, as the particle scatters on an atomic nucleus. The detection method is based on the fact that the scattering would heat up a calcium tungstate (CaWO4) crystal.

The challenge: the lighter the dark matter particle is, the smaller the energy deposited in the crystal is. Currently, no other direct dark matter search method has a threshold for nuclear recoils as low as 0.3 kiloelectronVolt (keV). As such, the CRESST-II team are the first to ever probe dark matter particle masses at such low mass scale (below one GeV/c^2-as far as 0.5GeV/c^2). The next-generation CRESST-III detector is currently being upgraded and promises to reach thresholds of 100 electronVolts (eV), following successful tests of prototypes.

From Science Daily

Exact formula now available for measuring scientific success

Scientometrics research is the science of evaluating scientific performance. Physics methods designed to predict growth based on a scale-free network have rarely been applied to this field. Now, scientists in Poland have developed an analytical method using a previously developed agent-based model to predict the h-index, probably the most popular citation-based scientific measurement, using bibliometric data. They are the very first to succeed in developing an exact formula to calculate the number of external citations and self-citations for each paper written by an author. These findings have just been published in EPJ B by Barbara Zogala-Siudem from the Systems Research Institute, Polish Academy of Sciences, Warsaw, and colleagues. It opens the door to applying this growth analysis to social network users or citations from different scientific fields.

Knowing an author's overall number of papers and total number of citations helps compute an approximated value of their h-index, which was named after the American physicist J.E. Hirsch in 2005 and measures the overall number of a scientist's publications as well as their quality and number of citations.

In this study, the authors relied on rate equations, a complex systems physics tool. To establish the equations governing the growth of citation networks, they incorporated a rule called the preferential attachment rule. Although this rule has been known for over 50 years, it remained unclear until now how and why such rules matter to the growth of the h-index. The explanation came from incorporating the rule into agent-based models representing citation networks, otherwise known as the Ionescu-Chopard (IC) model.

This led to exact h-index predictions- just like with the IC model alone -- and enabled the authors to explain some underlying bibliometric phenomena. For example, they showed that the h-index can be further investigated using the aggregation theory. Lastly, they verified their results with data from real authors as well as numerical simulations.

From Science Daily

Oysters Are Munching On Our Microplastics

Tiny pieces of plastic may endanger Pacific oysters by adversely affecting their reproduction, according to a new study. They may have similar effects on other marine bivalves, raising questions about their impacts on marine ecosystems more broadly.

The plastic pieces are known as microplastics are, which are defined as being anywhere from 5 mm in size to just 1 nanometer (0.000001 mm). Scientists refer to primary microplastics and secondary microplastics: the former are intentionally manufactured super-small, primarily used in cosmetics and personal care products, industrial scrubbers used for abrasive blast cleaning, microfibers used in textiles, and pellets used in plastic manufacturing processes; the latter are the result of larger pieces of plastic disintegrating over time.

Imagery of plastic pollution in the ocean often focuses on more visible impacts, such as trash that has become entangled around the neck of a marine mammal, or the appalling sight of vast amounts of plastic in the stomachs of seabirds on Midway Atoll. It is of course far harder to demonstrate the impacts of pollution that can not be seen, but those impacts are very real.

One of the great problems with microplastics is their ubiquity: It has been estimated that the ocean contains 5 trillion particles, totaling 250,000 tons, while a study last yearconcluded that 100,000 microbeads entered the ocean with each use of a personal cosmetic product that contained them. (The United States recently banned the production of personal care products containing microbeads from July 2017.) Just one cubic meter of ocean water may contain as many as 100,000 particles.

This is a problem particularly for filter feeding organisms such as mussels, sea cucumbers and some zooplankton, which may unintentionally consume large amounts of microplastics, which are often approximately the same size as their phytoplankton prey. Studies have shown that this can have adverse effects on those species’ energetics — unsurprisingly, as eating food-sized plastic is no substitute for eating actual food — as well as, in some cases, having immunological and neurological impacts. An additional concern is the leaching of chemical additives and pollutants from the microplastics.

The latest study, published today in the Proceedings of the National Academy of Sciences, examined the effects of microplastic exposure on reproductively active Pacific oysters — a species the study’s authors chose “because of its worldwide production, economic importance as seafood, and important role in estuarine and coastal habitats.”

The authors established a number of tanks of oysters, which they fed phytoplankton, and in half of the tanks also introduced microplastics. Oysters that were exposed to microplastics readily ingested particles that were similar in size to the phytoplankton and, after two months of exposure, produced fewer and smaller oocytes (cells from which ova grow) and slower sperm, compared with those that weren’t.

Furthermore, exposed oysters produced 41 percent fewer larvae, and those larvae grew at a slower rate and ultimately reached a size 18 percent smaller than larvae from the unexposed tanks.

Read more at Discovery News

Biological Brain-Twister Solved With 3D

The deep folds that give the adult human brain its wrinkled walnut appearance were Nature's solution to fitting a large, powerful processor into a small skull.

Like a piece of flat, square paper crumpled together to fit into a small, round hole, folding allows more neurons to be packed closer together, with shorter, faster connections between them.

While scientists have long understood why there are folds in the brain's outer layer, called the cerebral cortex or grey matter, the how has remained a mystery.

Do the creases develop as a result of genetic, biological or chemical signals? Or are they caused by physical forces?

On Monday, a team of researchers from the United States and Europe said the folds can be explained by physics -- a discovery that may have important implications for understanding certain brain disorders.

Folds in the cortex develop through buckling in weak spots which develop as the foetal brain grows, they said.

The brains of human foetuses are smooth for about the first 20 weeks, when folding begins and continues until the child is about 18 months old.

The surface area covered by the folded cortex is almost three times that of a smooth brain the size of our head, study co-author Lakshminarayanan Mahadevan from Harvard University in Massachusetts told AFP.

"The number, size, shape and position of neuronal cells during brain growth all lead to the expansion of the gray matter, known as the cortex, relative to the underlying white matter," he said by email.

"This puts the cortex under compression, leading to a mechanical instability that causes it to crease locally. This simple evolutionary innovation... allows for the thin but expansive cortex to be packed into a small volume, and is the dominant cause behind brain folding."

Mahadevan and a team used MRI scans of smooth foetus brains to build a three-dimensional gel model. They coated the surface with a thin layer of elastomer gel to represent the cortex.

To mimic brain growth, they immersed the gel brain in a solvent that was absorbed by the outer layer, causing it to swell relative to the deeper region.

Within minutes, folds started to appear that were remarkably similar in size and shape to the real thing, showing that the same process happened even though the model did not contain any living tissue.

"It looks like a real brain," said Mahadevan's colleague and fellow author Jun Young Chung.

A few other animals also have brain folds -- including chimpanzees, dolphins, elephants and pigs -- but the human brain is the wrinkliest of them all.

The physical explanation for brain folds was first proposed by Harvard scientists 40 years ago.

Now proven by Mahadevan's team, it was considered a controversial challenge at the time to the conventional wisdom that brain folds were created by purely biological, not physical, processes.

Read more at Discovery News

Bringing time and space together for universal symmetry

"While we are indeed moving forward in time, there is also always some movement backwards, a kind of jiggling effect," Professor Vaccaro said.

New research from Griffith University's Centre for Quantum Dynamics is broadening perspectives on time and space.

In a paper published in the journal Proceedings of the Royal Society A, Associate Professor Joan Vaccaro challenges the long-held presumption that time evolution -- the incessant unfolding of the universe over time -- is an elemental part of Nature.

In the paper, entitled "Quantum asymmetry between time and space," she suggests there may be a deeper origin due to a difference between the two directions of time: to the future and to the past.

"If you want to know where the universe came from and where it's going, you need to know about time," says Associate Professor Vaccaro.

"Experiments on subatomic particles over the past 50 years ago show that Nature doesn't treat both directions of time equally.

"In particular, subatomic particles called K and B mesons behave slightly differently depending on the direction of time.

"When this subtle behaviour is included in a model of the universe, what we see is the universe changing from being fixed at one moment in time to continuously evolving.

"In other words, the subtle behaviour appears to be responsible for making the universe move forwards in time.

"Understanding how time evolution comes about in this way opens up a whole new view on the fundamental nature of time itself.

"It may even help us to better understand bizarre ideas such as travelling back in time."

According to the paper, an asymmetry exists between time and space in the sense that physical systems inevitably evolve over time whereas there is no corresponding ubiquitous translation over space.

This asymmetry, long presumed to be elemental, is represented by equations of motion and conservation laws that operate differently over time and space.

However, Associate Professor Vaccaro used a "sum-over-paths formalism" to demonstrate the possibility of a time and space symmetry, meaning the conventional view of time evolution would need to be revisited.

"In the connection between time and space, space is easier to understand because it's simply there. But time is forever forcing us towards the future," says Associate Professor Vaccaro.

Read more at Science Daily

Completely new kind of polymer could lead to artificial muscles, self-repairing materials

Northwestern University researchers have developed a new hybrid polymer with removable supramolecular compartments, shown in this molecular model.

Imagine a polymer with removable parts that can deliver something to the environment and then be chemically regenerated to function again. Or a polymer that can lift weights, contracting and expanding the way muscles do.

These functions require polymers with both rigid and soft nano-sized compartments with extremely different properties that are organized in specific ways. A completely new hybrid polymer of this type has been developed by Northwestern University researchers that might one day be used in artificial muscles or other life-like materials; for delivery of drugs, biomolecules or other chemicals; in materials with self-repair capability; and for replaceable energy sources.

"We have created a surprising new polymer with nano-sized compartments that can be removed and chemically regenerated multiple times," said materials scientist Samuel I. Stupp, the senior author of the study.

"Some of the nanoscale compartments contain rigid conventional polymers, but others contain the so-called supramolecular polymers, which can respond rapidly to stimuli, be delivered to the environment and then be easily regenerated again in the same locations. The supramolecular soft compartments could be animated to generate polymers with the functions we see in living things," he said.

Stupp is director of Northwestern's Simpson Querrey Institute for BioNanotechnology. He is a leader in the fields of nanoscience and supramolecular self-assembly, the strategy used by biology to create highly functional ordered structures.

The hybrid polymer cleverly combines the two types of known polymers: those formed with strong covalent bonds and those formed with weak non-covalent bonds, well known as "supramolecular polymers." The integrated polymer offers two distinct "compartments" with which chemists and materials scientists can work to provide useful features.

The study will be published in the Jan. 29 issue of Science.

"Our discovery could transform the world of polymers and start a third chapter in their history: that of the 'hybrid polymer,'" Stupp said. "This would follow the first chapter of broadly useful covalent polymers, then the more recent emerging class of supramolecular polymers.

"We can create active or responsive materials not known previously by taking advantage of the compartments with weak non-covalent bonds, which should be highly dynamic like living things. Some forms of these polymers now under development in my laboratory behave like artificial muscles," he said.

Polymers get their power and features from their structure at the nanoscale. The covalent rigid skeleton of Stupp's first hybrid polymer has a cross-section shaped like a ninja star -- a hard core with arms spiraling out. In between the arms is the softer "life force" material. This is the area that can be animated, refreshed and recharged, features that could be useful in a range of valuable applications.

"The fascinating chemistry of the hybrid polymers is that growing the two types of polymers simultaneously generates a structure that is completely different from the two grown alone," Stupp said. "I can envision this new material being a super-smart patch for drug delivery, where you load the patch with different medications, and then reload it in the exact same compartments when the medicine is gone."

Stupp also is the Board of Trustees Professor of Materials Science and Engineering, Chemistry, Medicine and Biomedical Engineering and holds appointments in Northwestern University Feinberg School of Medicine, the McCormick School of Engineering and Applied Science and the Weinberg College of Arts and Sciences.

Stupp and his research team also discovered that the covalent polymerization that forms the rigid compartment is "catalyzed" by the supramolecular polymerization, thus yielding much higher molecular weight polymers.

The strongly bonded covalent compartment provides the skeleton, and the weakly bonded supramolecular compartment can wear away or be used up, depending on its function, and then be regenerated by adding small molecules. After the simultaneous polymerizations of covalent and non-covalent bonds, the two compartments end up bonded to each other, yielding a very long, perfectly shaped cylindrical filament.

To better understand the hybrid's underlying chemistry, Stupp and his team worked with George C. Schatz, a world-renowned theoretician and a Charles E. and Emma H. Morrison Professor of Chemistry at Northwestern. Schatz's computer simulations showed the two types of compartments are nicely integrated with hydrogen bonds, which are bonds that can be broken. Schatz is a co-author of the study.

Read more at Science Daily