Cicada wings are unique

Posted on April 15, 2020 by petrel41

This 2013 video from the USA is called Magicicada cassini cicadas molt (shed their skin) + Slow Motion & Fast Motion.

From the University of Illinois at Urbana-Champaign, News Bureau in the USA:

Unique physical, chemical properties of cicada wings

April 14, 2020

Biological structures sometimes have unique features that engineers would like to copy. For example, many types of insect wings shed water, kill microbes, reflect light in unusual ways and are self-cleaning. While researchers have dissected the physical characteristics that likely contribute to such traits, a new study reveals that the chemical compounds that coat cicada wings also contribute to their ability to repel water and kill microbes.

The scientists report their findings in the journal Advanced Materials Interfaces.

The researchers looked at the physical traits and chemical characteristics of the wings of two cicada species, Neotibicen pruinosus and Magicicada casinnii. N. pruinosus is an annual cicada; M. casinnii emerges from the soil once every 17 years. Previous studies have shown that both species have a highly ordered pattern of tiny pillars, called nanopillars, on their wings. The nanopillars contribute to the wings’ hydrophobicity — they shed water better than a raincoat — and likely play a role in killing microbes that try to attach to the wings.

“We knew a lot about the surface structure of cicada wings before this study, but we knew very little about the chemistry of those structures,” said Marianne Alleyne, an entomology professor at the University of Illinois at Urbana-Champaign who led the study with analytical chemist Jessica Román-Kustas, of the Sandia National Laboratories in Albuquerque, New Mexico; Donald Cropek, of the U.S. Army Corps of Engineers’ Construction Engineering Research Laboratory; and Nenad Miljkovic, a professor of mechanical science and engineering at Illinois.

To study nanopillar chemistry, Román-Kustas developed a method to gradually extract the compounds on the surface without damaging the overall structure of the wings. She placed each wing in solvent in an enclosed chamber and slowly microwaved each one.

“We extracted all these different compounds over different time periods, and then we analyzed what came off,” Román-Kustas said. “And we also looked at the corresponding changes in the nanopillar structure.”

The effort revealed that cicada wings are coated in a stew of hydrocarbons, fatty acids and oxygen-containing molecules like sterols, alcohols and esters. The oxygen-containing molecules were most abundant deeper in the nanopillars, while hydrocarbons and fatty acids made up more of the outermost nanopillar layers.

“Finding these particular molecules on the surface is not a surprise,” Alleyne said. “Hydrocarbons and fatty acids on insect cuticle is fairly common.”

The ratio of surface chemicals differed between the two cicada species, as did their nanopillar structures.

The study revealed that altering the surface chemicals also changed the nanopillar structure. In the N. pruinosis cicadas, the nanopillars began to shift in relation to one another as the chemicals were extracted, and later shifted back to a more parallel configuration. This also changed the wings’ wettability and anti-microbial characteristics.

The wings of the M. cassinni cicadas had shorter nanopillars and a higher proportion of hydrophobic compounds on their surface. Their nanopillar configuration orientation did not change as a result of extracting their surface chemicals.

While preliminary, the new findings offer insight into the interplay of structure and chemistry in determining function, Alleyne said. By dissecting these characteristics, the researchers hope to one day design artificial structures with some of the same surface traits. Finding materials that shed water and kill microbes, for example, would be useful in many applications, from agriculture to medicine, she said.

Alleyne is also an affiliate of the Beckman Institute for Advanced Science and Technology at Illinois.

The U.S. Army Corps of Engineers’ Construction Engineering Research Laboratory, National Science Foundation and the Japanese Ministry of Education, Culture, Sports, Science, and Technology supported this research.

How great cormorants hear, new research

Posted on April 2, 2020 by petrel41

This 2015 video from Britain says about itself:

BTO Bird ID – Cormorant and Shag

A black, reptilian-looking bird swims by low to the water – but is it a Cormorant or a Shag? Cormorants are more familiar and wide-spread, although Shags are more numerous. Let us help you to separate these two similar-looking species of waterbird.

From the University of Southern Denmark:

Surprising hearing talents in cormorants

April 1, 2020

Summary: The great cormorant has more sensitive hearing under water than in air. This new knowledge may help protect vulnerable bird species.

Many aquatic animals like frogs and turtles spend a big part of their lives under water and have adapted to this condition in various ways, one being that they have excellent hearing under water.

A new study shows that the same goes for a diving bird, the great cormorant.

This is surprising because the great cormorant spends most of its time out of the water. It is the first time we see such extensive hearing adaptations in an animal that does not spend most of its time under water, says biologist Jakob Christensen-Dalsgaard, University of Southern Denmark.

Human noise is a problem for animals at sea

Researchers are increasingly paying attention to the living conditions of animals living in or near the oceans.

Oceans are no longer the quiet habitats they used to be. Human activities produce noise — examples are ship traffic, fishing and windmill constructions, and this noise may pose a threat to the oceans’ animals.

“We need more knowledge about how animals are affected by this noise — does it impair their hearing or their hunting and fishing abilities? We have studied the effect on whales for some time now, but we don’t know very much about diving birds. There are many vulnerable animal species living or foraging at sea, that may be negatively affected by human noise,” says Jakob Christensen-Dalsgaard.

Listening for fish?

“Even though the great cormorant is not an aquatic animal, it does frequently visit the water columns, so it makes sense that it, too, has adapted its ears for hearing under water,” Jakob Christensen-Dalsgaard says about the new study.

Whereas the great cormorant spends about 30 seconds foraging under water in active pursuit of prey, approximately 150 other species of diving birds spend up to several minutes in pursuit of fish and squid.

Foraging under water is challenging for the sensory apparatus of the birds, however, and for most birds, their visual acuity under water is no better than that of humans. So, the birds may use other sensory modalities.

We know very little about birds’ hearing under water

Apart from a few behavioral studies, the hearing of birds under water is unknown.

Previously, researchers from University of Southern Denmark, have documented that great cormorants and gentoo penguins respond to sound under water, but this is the first study of the physiology of underwater hearing in any bird.

The study shows that the cormorant ear has been specialized for underwater hearing.

How was the study done?

To study hearing of the cormorant in air and under water the scientists measured auditory evoked responses and neural activity in response to airborne and underwater sound in anesthetized birds.

The neural responses to airborne and underwater sounds were measured using electrodes under the skin. In this way, the scientists could measure hearing thresholds to sound in air and under water.

Thresholds in water and air proved to be similar, with almost the same sensitivity to sound pressure in the two media. This is surprising, because similar sound pressures in air and water means that the threshold sound intensity (the energy radiated by the sound wave) is much lower in water, so the ear is more sensitive to underwater than to airborne sound.

The cost: Stiffer and heavier eardrums

“We found anatomical changes in the ear structures compared to terrestrial birds. These changes may explain the good sensitivity to underwater sound. The adaptations also may provide better protection of the eardrums from the water pressure,” says Jakob Christensen-Dalsgaard.

But there is — as always in Nature — a cost to these benefits:

Their hearing in air is not as sensitive as in many other birds. Their eardrums are stiffer and heavier.

How has the ear adapted?

The cormorant eardrum shows large vibrations in response to underwater sound, so the sensitivity likely is mediated by the eardrum and middle ear.

Underwater eardrum vibrations and anatomical features of the cormorant ear are similar to features found in turtles and aquatic frogs, that also appear to be specialized for underwater hearing.

The data suggest convergent modifications of the tympanic ear in these three distantly related species, and similar modifications may be found in other diving birds.

The colour yellow in ancient Egypt

Posted on October 16, 2019 by petrel41

This January 2018 video says about itself:

The world’s first artificial pigment, Egyptian blue, may help scientists prevent forgery and even save lives.

From the University of Southern Denmark:

Discovered: Unknown yellow colors from antiquity

October 15, 2019

Summary: Antique artefacts have been studied by chemists, revealing a hitherto unknown use of yellow in Ancient Egypt

Archaeologists have long known that artefacts from the Antiquity were far more colorful than one would think when looking at the bright white statues and temples, left behind for today.

The statues and buildings only appear white today because the colors have degraded over time. Initially, lots of colors were in use.

This was also true for King Apries I‘s palace in Ancient Egypt. This palace was situated in the Nile Delta, and from here King Apries ruled from 589 to approx. 568 BC.

Fragments of the palace are today kept at the Glyptoteket Museum in Copenhagen, and recently they have been the focus of a collaboration between archaeologists from Glyptoteket, the British Museum, the University of Pisa and a chemist from the University of Southern Denmark.

“We are interested in learning more about the use of pigments, binders and the techniques associated with using them in the Antuquity. It has an obvious relevance for art historians, but it can also tell us about how different cultures in the Mediterranean and the Near East exchanged materials and knowledge and thus connected,” says Cecilie Brøns, classical archaeologist at Glyptoteket.

With this in mind, the archaeologists have worked with professor of archaeometry Kaare Lund Rasmussen from the University of Southern Denmark.

Professor Rasmussen is an expert in conducting advanced chemical analyzes of archaeological objects. Among other things, he has examined the beard of renaissance astronomer Tycho Brahe, Italian monk skeletons, medieval syphilis-infested bones, sacred relics and the Dead Sea Scrolls.

For this project he has taken samples of the palace fragments to learn more about the pigments and binders used.

The project has resulted in two scientific articles, the last one just been published. They can both be found in the journal Heritage Science.

“We have discovered no less than two pigments whose use in Antiquity has hitherto been completely unknown,” says Kaare Lund Rasmussen.

These are lead-antimonate yellow and lead-tin yellow. Both are naturally occurring mineral pigments.

“We do not know whether the two pigments were commonly available or rare. Future chemical studies of other antiquity artefacts may shed more light,” he says.

Lead-antimonate yellow and lead-tin yellow have so far only been found in paintings dating to the Middle Ages or younger than that. The oldest known use of lead-tin yellow is in European paintings from ca. 1300 AD. The oldest known use of lead-antimonate yellow is from the beginning of the 16th century AD.

Analyzing binders is more difficult than analyzing pigments. Pigments are inorganic and do not deteriorate as easily as most binders which are organic and therefore deteriorate faster.

Nevertheless, Kaare Lund Rasmussen’s Italian colleagues from Professor Maria Perla Colombini’s research group at the University of Pisa managed to find traces of two binders, namely rubber and animal glue.

The rubber is probably tapped from an acacia tree and served as a solvent for powdered pigment. Rubber was widely used as a binder, and it has also been found on stone columns in the Karnak Temple and murals in Queen Nefertite‘s tomb.

Animal glue was also commonly available. It was made by boiling animal parts, in particular the hides and bones, in water to a gel-like mass which could be dried and pulverized. When needed, the powder was stirred with warm water and ready to use.

The researchers also found these color pigments:

Calcite (white).

Gypsum (white).

Egyptian Blue (a synthetic pigment, invented in the 3rd millennium BC)

Atacamite (green).

Hematite (red).

Orpiment (golden yellow).

20 ancient coffins discovered in Luxor, Egypt: here.

Why some Renaissance paintings turned brown

Posted on October 3, 2019 by petrel41

This 2014 video from the USA says about itself:

Go behind the scenes with Carnegie Museum Of Art chief conservator Ellen Baxter as she discusses the restoration process of a portrait of Isabella de’ Medici.

Artwork:
Alessandro Allori
Portrait of Isabella de’ Medici, c. 1570-1574
oil on canvas (transferred from panel)
Gift of Mrs. Paul B. Ernst

Filmed in conjunction with the exhibition “Faked, Forgotten, Found: Five Renaissance Paintings Investigated.”

From the American Chemical Society in the USA:

Why some greens turn brown in historical paintings

October 2, 2019

Enticed by the brilliant green hues of copper acetate and copper resinate, some painters in the Renaissance period incorporated these pigments into their masterpieces. However, by the 18th century, most artists had abandoned the colors because of their tendency to darken with time. Now, researchers reporting in ACS’ journal Inorganic Chemistry have uncovered the chemistry behind the copper pigments’ color change.

Copper acetate (also known as verdigris) and copper resinate were used in European easel paintings between the 15th and 17th centuries. Artists typically mixed these pigments with linseed oil to make paint. Until now, scientists didn’t know why the green paints often turned brown with time, although they had some clues. Light exposure was thought to play a role because areas of paintings protected by frames remained green. Also, oxygen appeared to contribute to the darkening process, with the brown color spreading from cracks in the paint that exposed the underlying copper pigments to air. So Didier Gourier and colleagues wanted to analyze the chemical changes that occur in the paints upon light exposure.

The team determined that the molecular structures of copper acetate and copper resinate were quite similar: Both had two copper atoms bridged by four carboxylate groups, but there was more space between resinate than acetate molecules. The researchers mixed the pigments with linseed oil and spread them in a thin layer. They then exposed the paint films to 16 hours of 320-mW LED light, which corresponded to hundreds of years of museum light. This illumination caused bridging molecules between the pair of copper atoms to be lost, which were then replaced by an oxygen molecule, creating bimetallic copper molecules responsible for the brown color. This process occurred more readily for copper resinate than for copper acetate. Boiling the linseed oil before mixing, which some artists did to improve the drying process, slowed the darkening reaction.

Paolo Uccello: the father of perspective. The Italian artist developed the technique which changed painting forever: here.

Fish warn others chemically about dangers

Posted on April 21, 2019 by petrel41

This june 2013 video is called Fathead minnows in my pond.

From the University of Saskatchewan in Canada:

Fish under threat release chemicals to warn others of danger

April 18, 2019

Fish warn each other about danger by releasing chemicals into the water as a signal, research by the University of Saskatchewan (USask) has found.

The USask researchers discovered that wild fish release chemicals called ‘disturbance cues’ to signal to other fish about nearby dangers, such as predators.

The findings may have implications for fish conservation efforts across the globe.

“Disturbance cues may help to explain why some fish populations crash after they decline past a certain point,” said Kevin Bairos-Novak, a graduate student member of the research team.

While researchers have been aware that fish release chemicals into the water for 30 years, this is the first time their use has been studied.

The findings, involving researchers from the USask biology department and the Western College of Veterinary Medicine, are published in the Journal of Animal Ecology.

Fish signaled most when in the presence of familiar fish, but signaled far less or not at all when in the presence of strangers, or when on their own.

The signals provoked a ‘fright response’ in fish they knew, including freezing, dashing about and then shoaling tightly together. Fish use this behavior to defend themselves against predators.

“When minnows

The research is about fathead minnows. They live in North America.

were present alongside familiar minnows, they were much more likely to produce signals that initiated close grouping of nearby fish, a strategy used to avoid being eaten by predators,” said Bairos-Novak, who is now at James Cook University, Australia.

Disturbance cues are voluntarily released by prey after being chased, startled or stressed by predators.

One of the main constituents of the signal is urea, found in fish urine.

Fathead minnows, caught at a lake, were placed in groups with familiar fish, unfamiliar fish or as isolated individuals. The research team then simulated a predator chase. The fish responded by shoaling, freezing and dashing when they received a signal from a group they knew. But they did not take significant defensive action when receiving cues from unfamiliar fish or isolated minnows.

Disturbance cues are voluntarily released by prey after being chased, startled or stressed by predators.

“It is exciting to discover a new signaling pathway in animals,” said Maud Ferrari, Bairos-Novak’s supervisor and a behavioural ecologist in the veterinary college’s Department of Veterinary Biomedical Sciences. “We found that fish are able to manipulate the behaviour of other individuals nearby by issuing a signal.”

The research was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).

Chemical periodic table, 150 years

Posted on January 13, 2019 by petrel41

Periodic table

By Elizabeth Quill, 11:29am, January 8, 2019:

150 years on, the periodic table has more stories than it has elements

Its organization holds stories of discovery and strange reactions

Recognize these rows and columns? You may remember a detail or two about this mighty table’s organization from a long-ago chemistry class. Elements are ordered according to their number of protons, or atomic number. Metals are mostly to the left and nonmetals to the right. The column at the far right holds the noble gases, named for their general unwillingness to interact with other elements.

When Dmitrii Mendeleev proposed his periodic table 150 years ago, no one knew what was inside an atom. Today, we know that an element’s place on the table, along with its chemical properties, has a lot to do with the element’s proton number as well as how its electrons are configured.

In one glance, you can see the elements that make up nature’s entire repertoire of chemical substances plus how those elements relate to one another. But the elements are also individuals, with scientific idiosyncrasies and nuanced stories of discovery. A few of our favorites are on these pages.

And the table is still a work in progress. Four elements were named as recently as 2016. Boundary-busting research efforts, along with scientific mysteries, remain.

Potassium

Bananas are rich in potassium-40, a radioactive version of potassium. In a single banana, the potassium-40 produces a positron, the antimatter version of the electron, a dozen or so times a day, as well as an electron about 13 times a second.

Lutetium, Lawrencium, Lanthanum, Actinium

Not everyone is convinced that lutetium and lawrencium belong in the upper positions shown here. The Royal Society of Chemistry instead puts lanthanum and actinium in these upper boxes, prioritizing outer electron configurations and sticking lutetium and lawrencium at the end of the f-block. The International Union of Pure and Applied Chemistry, responsible for chemical naming, has been exploring the placement question since 2015.

Uranium

When Henri Becquerel, a French physicist, placed uranium salts atop photographic plates in 1896, he accidentally discovered radioactivity, for which he won the Nobel Prize in physics in 1903. Uranium is the last element on the table that occurs in any meaningful abundance in nature; the rest must be created in the lab.

Gold

Albert Einstein’s special theory of relativity explains gold’s color. Because of how electron energy levels shift due to relativity, the metal absorbs blue light, giving the reflected light a yellow hue.

Mercury

When Meriwether Lewis and William Clark set out to reach the Pacific Ocean, they carried 1,300 doses of a mercury-based laxative known as Rush’s Thunderbolts. Mercury discovered in the ground in Lolo, Mont., nearly two centuries later clued experts in to the location of one of the explorers’ campsites.

Gallium

Mendeleev left blank spaces in his original periodic table so that he could properly line up the known elements. Gallium, element 31, was his first gap to be filled, in 1875. The star of a popular chemistry trick, the metal gallium is solid at room temperature but liquid above 29.7° Celsius. It can be formed into a spoon that melts in the hand or in hot tea.

Helium

Helium was discovered as a bright yellow line in a spectrum of light from the sun in 1868, almost three decades before the element was found on Earth. Last year, scientists reported the first sighting of helium in the atmosphere of an exoplanet.

Chlorine, Bromine, Iodine

Chlorine, bromine and iodine make up what German chemist Johann Wolfgang Döbereiner called a “triad”. Bromine’s atomic weight of 79.90 is halfway between chlorine’s (35.45) and iodine’s (126.90), and all react readily with metals to form salts. Döbereiner recognized such relationships in 1817, more than a half century before Mendeleev proposed his table.

Oganesson

Oganesson marks the end of today’s periodic table, capping the noble gases column. Yet it isn’t as aloof as others in its group. The element will readily give or take electrons, and its atoms may clump together — at least according to theoretical predictions. The few atoms of oganesson that chemists have made survived for less than a millisecond. Scientists continue smashing atoms together in the lab in search of elements beyond 118.

This Greek philosopher had the right idea, just too few elements. Empedocles didn’t make a periodic table, but identified basic concepts of matter and force: here.

Ancient organic molecules discovery on Mars

Posted on June 7, 2018 by petrel41

This NASA video from today in the USA says about itself:

The Curiosity rover has discovered ancient organic molecules on Mars, embedded within sedimentary rocks that are billions of years old. News Release: here.

From Chemical & Engineering News today:

Ancient organic molecules found on Mars

Curiosity rover also reports data on the red planet’s mysterious methane plumes

by Mark Peplow

Wherever life flourishes, it leaves a calling card written in organic molecules—and researchers have spent decades hoping to uncover these telltale signatures on Mars.

NASA’s Mars rover Curiosity has now given those hopes a considerable boost after finding organic deposits trapped in exposed rocks that were formed roughly 3.5 billion years ago (Science 2018). The rover’s discovery at Gale Crater shows that organic molecules were present when that part of the red planet hosted a potentially habitable lake. It also proves that these traces can survive through the ages, ready to be discovered by robot explorers.

“We started this search 40 years ago, and now we finally have a set of organic molecules that tells us this stuff is preserved near the surface,” says Jennifer L. Eigenbrode of NASA’s Goddard Space Flight Center, who led the study.

Curiosity gathered mudstone samples and gradually heated them to 860 ºC, using gas chromatography/mass spectrometry to study the gases produced. It identified a smorgasbord of molecules, including thiophene, methylthiophenes, and methanethiol, which are probably fragments from larger organic macromolecules in the sediment. These organic deposits may be something like kerogen, the fossilized organic matter found in sedimentary rocks on Earth that contains a jumble of waxy hydrocarbons and polycyclic aromatic hydrocarbons.

The organic compounds that were originally transformed into martian kerogen could have come from three possible sources—geological activity, meteorites, or living organisms—but Curiosity’s data offer no insight on that question. “The most plausible source of these organics is from outside the planet,” says Inge Loes ten Kate, an astrobiologist at Utrecht University, who was not involved in the research. She notes that roughly 100 to 300 metric tons of organic molecules arrive on Mars every year, hitching a ride on interplanetary dust particles. “Three billion years ago, it was much more hectic in the solar system”, ten Kate says, so there would have been much larger deliveries of organics via interplanetary travelers.

Curiosity had previously detected chlorocarbons in martian soil, which were probably generated by reactions with the abundant perchlorate found on the planet’s surface. In contrast, the mudstone samples have delivered “what we expect of natural organic matter,” Eigenbrode says.

Methane mystery

Meanwhile, the rover’s infrared spectrometer has been tackling the long-standing puzzle of martian methane (Science 2018). Orbiting Mars probes, along with telescopes on Earth, have previously seen occasional plumes of methane in the planet’s atmosphere, raising speculation that the gas could have come from geological activity or even methane-producing organisms.

Curiosity has taken methane measurements over 55 Earth months, spanning three martian years, which now reveal that the atmospheric concentration of the gas varies seasonally between 0.24 and 0.65 parts per billion by volume. “This is the first time that Mars methane has shown any repeatability”, says Christopher R. Webster at NASA’s Jet Propulsion Laboratory, who led the work. “It always seemed kind of random before.”

The rover also saw brief spikes in methane concentration to about 7 ppbv, which is consistent with previous remote observations of plumes, says Michael J. Mumma of NASA’s Goddard Space Flight Center, who has been chasing martian methane for more than 15 years but was not involved in Curiosity’s latest findings. “The ground-based detection is very important because it confirms the methane is there,” he says.

The methane’s source is still an open question. But Webster’s team says that the seasonal cycle rules out one of the leading suggestions: that organic molecules, delivered to the surface by meteorites and space dust, were broken down by ultraviolet light to produce the gas.

Instead, the cyclical nature of the data suggests that methane could be stored deep underground in icy crystals called clathrates and slowly escape to the planet’s topsoils. Laboratory experiments suggest that the soil could temporarily hang on to the gas, releasing more of it in the warmer martian summer to produce the seasonal cycles.

Mars’s newest satellite, the European Space Agency’s Trace Gas Orbiter (TGO), could help confirm that idea. It began to survey the whole planet for methane in April. “We’re all waiting with bated breath to see what they find,” Webster says. TGO should also measure the carbon isotope ratios in the methane it detects, which may provide hints at a biological or geological origin. And in 2021, ESA expects to land a rover on Mars that could drill up to 2 meters below the surface, where there might be better-preserved organics compared with the ones collected at Gale Crater, Eigenbrode says.

These lines of evidence could eventually help resolve questions about our own origins. Mars and Earth were once quite similar places, ten Kate says, yet life apparently failed to gain a foothold on the red planet. “Was there really no life on Mars, or did it just not survive?” she says. The answer could shed light on the crucial conditions needed to nurture the first life-forms on our own world.

London Grenfell disaster survivor girl gets top school grades

Posted on August 25, 2017 by petrel41

This TV video from Britain says about itself:

16 June 2017

16-year-old Ines Alves and her brother Tiago lived on the 13th floor of Grenfell Tower. They both ended up running for lives on the night of the fire, but the very next morning, Ines went back to school to sit her chemistry GCSE exam. They share their story.

By Felicity Collier in London, England:

Grenfell: Survivor who sat exam hours after fire gets top grades

Friday 25th August 2017

A TEENAGER who escaped from Grenfell Tower and sat her chemistry GCSE the next morning was awarded an A grade yesterday.

Ines Alves, who lived with her family on the 13th floor, fled the fire in the middle of the night with just her mobile phone and chemistry notes before sitting the exam at 9am still wearing the same clothes.

The 16-year-old also scored the highest possible grades in maths — a 9 which is equivalent to an A* under the old system — and A* in Spanish.

Sacred Heart High School head teacher Marian Doyle called her results “fantastic.”

“It must have been so hard for her to actually come in and do that and try to blot out the scenes of what she had seen,” she said.

The student said that at first she thought the fire was “nothing major” and had just wanted to sit the paper, adding: “There was no point me carrying on watching the building burning so I just went in.”

Asked what she remembered from the night, she said: “The whole thing. The screaming, people screaming, begging for help.”

More than two months on Ms Alves’s family — who owned the flat — are living in a hotel and are still waiting until they are offered a permanent home.

‘Oxygen on comet 67P not that ancient’

Posted on May 9, 2017 by petrel41

This 8 May 2017 video is called Study Suggests Alternative For Oxygen Formation On Comets.

From Science News:

Oxygen on comet 67P might not be ancient after all

Newly discovered chemical reaction could generate the gas instead, study suggests

By Ashley Yeager

12:28pm, May 8, 2017

Oxygen on comets might not date all the way back to the birth of the solar system.

Instead, interactions between water, particles streaming from the sun and grains of sand or rust on the comet’s surface could generate the gas. Those interactions could explain the surprising abundance of O₂ detected in the fuzzy envelope of gas around comet 67P/Churyumov-Gerasimenko in 2015 (SN: 11/28/15, p. 6), researchers report May 8 in Nature Communications. Such reactions might also reveal how oxygen forms in other regions of space.

“Molecular oxygen is very hard to find out there in the universe,” says Caltech chemical engineer Konstantinos Giapis. When the Rosetta spacecraft detected oxygen around comet 67P, astronomers argued it must be primordial, trapped in water ice as the comet formed roughly 4.6 billion years ago. Intrigued by the result, Giapis and Caltech colleague Yunxi Yao wanted to see if an alternative way to create O₂ existed. Drawing on their work with fast-moving charged particles and materials such as silicon, they performed experiments that showed that charged water particles could slam into rust or sand grains and generate O₂.

Something similar could happen on comet 67P, they suggest. As the sun evaporates water from the comet’s surface, ultraviolet light could strip an electron from the water, giving it a positive charge. Then, fast-moving particles in the solar wind could shoot the ionized water back toward the comet’s surface, where it could collide with rust or sand particles. Atoms of oxygen from the water could pair with atoms of oxygen from the rust or sand, creating O₂.

The idea is plausible, says Paul Goldsmith, an astrophysicist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. He helped discover O₂ in the Orion nebula and says the reaction might happen in places where young stars are forming and in other regions of space.

Rosetta mission scientist Kathrin Altwegg of the University of Bern in Switzerland calls the result interesting, but is skeptical it can explain comet 67P’s oxygen abundance. As the comet gets closer to the sun, a protective bubble develops around 67P, data from the mission showed; that bubble would prevent solar wind particles or other ionized particles from reaching the comet’s surface, Altwegg says. Also, the ratio of oxygen to un-ionized water also stays constant over time. It should be more variable if this chemical reaction were generating oxygen on the comet, she says.

Goldsmith, however, suggests researchers keep an open mind and design missions with instruments to test whether this newly detected reaction does, in fact, generate oxygen in space.

See a new mosaic of images of comet 67P from the Rosetta mission: here.

The cigar-shaped object called ‘Oumuamua spotted tumbling through space last year is a comet, scientists have confirmed. ‘Oumuamua was the first interstellar object found passing through our solar system.

‘Oumuamua might be a shard of a broken planet. Simulations led to this new origin story for the first known visitor to our solar system: here.

Gold, new chemical discoveries

Posted on January 24, 2017 by petrel41

This video says about itself:

18 July 2012

In this video we explore the chemical resistance of gold.

The gold coin survives hydrochloric acid, nitric acid, sulfuric acid, bleach (sodium hypochlorite) and sodium hydroxide

From Science News:

Chemists strike gold, solve mystery about precious metal’s properties

Predicted, actual energy needed for ionization now match

By Emily Conover

7:00am, January 23, 2017

Gold’s glimmer is not the only reason the element is so captivating. For decades, scientists have puzzled over why theoretical predictions of gold’s properties don’t match up with experiments. Now, highly detailed calculations have erased the discrepancy, according to a paper published in the Jan. 13 Physical Review Letters.

At issue was the energy required to remove an electron from a gold atom, or ionize it. Theoretical calculations of this ionization energy differed from scientists’ measurements. Likewise, the energy released when adding an electron — a quantity known as the electron affinity — was also off the mark. How easily an atom gives up or accepts electrons is important for understanding how elements react with other substances.

“It was well known that gold is a difficult system,” says chemist Sourav Pal of the Indian Institute of Technology Bombay, who was not involved with the study. Even gold’s most obvious feature can’t be explained without calling Einstein’s special theory of relativity into play: The theory accounts for gold’s yellowish color. (Special relativity shifts around the energy levels of electrons in gold atoms, causing the metal to absorb blue light, and thereby making reflected light appear more yellow).

With this new study, scientists have finally resolved the lingering questions about the energy involved in removing or adding an electron to the atom. “That is the main significance of this paper,” Pal says.

Early calculations, performed in the 1990s, differed from the predicted energies by more than a percent, and improved calculations since then still didn’t match the measured value. “Every time I went to a conference, people discussed that and asked, ‘What the hell is going on?’” says study coauthor Peter Schwerdtfeger, a chemist at Massey University Auckland in New Zealand.

The solution required a more complete consideration of the complex interplay among gold’s 79 electrons. Using advanced supercomputers to calculate the interactions of up to five of gold’s electrons at a time, the scientists resolved the discrepancy. Previous calculations had considered up to three electrons at a time. Also essential to include in the calculation were the effects of special relativity and the theory of quantum electrodynamics, which describes the quantum physics of particles like electrons.

The result indicates that gold indeed adheres to expectations — when calculations are detailed enough. “Quantum theory works perfectly well, and that makes me extremely happy,” says Schwerdtfeger.

Smashing gold ions creates most swirly fluid ever. Record-making vorticity found in quark-gluon plasma. By Emily Conover, 12:00pm, February 8, 2017: here.