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Mon, 26 Oct 2020
The World for People who Think

Science & Technology


Could most positive COVID-19 tests be wrong?

covid test
A lot of people are bad with numbers, and especially so in the area of probability. Earlier this year (with accidental prescience), in the school where I work, as part of our off-curriculum 'mind-broadening' provision for sixth-formers, a few of my colleagues and I presented students with a puzzle involving imperfect methods of testing for rare conditions. Such puzzles can yield startling results - ones which even bright students are often reluctant to accept.

For example, if the incidence of a disease in the population is 0.1% and the test has a false positive rate of 5%, the probability that a randomly-selected individual testing positive actually has the disease is approximately one in fifty: about 2%, or a probability of 0.02.

Though this is easy to demonstrate, it is remarkable how resistant many perfectly intelligent people are to the conclusion, even when shown the proof. "But the test is 95% reliable", they protest. "How can it be that a person with a positive test has anything less than a 95% chance of having the disease?"

That kind of response merits attention. It does so because it is an example of an important failure to understand relevant data (and/or the terminology used to describe those data); and it is a failure that renders people blind (or, worse, resistant) to legitimate concerns about the significance of the published results of recent mass testing - concerns that are still not receiving the wider public attention that they deserve.


Simple patterns on solar panels boosts light absorption by 125%

pattern solar panel
© Dr Davide Zecca
Solar panels offer huge potential to move more people away from electricity generated from burning coal, and a new innovation devised by scientists stands to more than double the amount of light captured by conventional solar cells.

Comment: We are not yet in any position to move away from more reliable sources of energy.

In a new study, a team of scientists from the UK, Portugal, and Brazil discovered that etching a shallow pattern of grating lines in a checkerboard design on solar cells can enhance the current generated by crystalline silicon (c-Si) by as much as 125 percent.

"We found a simple trick for boosting the absorption of slim solar cells," explains photovoltaics researcher Christian Schuster from the University of York.

Comment: See also: New research finds solar panels could produce energy at night

Evil Rays

Nokia wins NASA contract to put a 4G network on the moon

© NASA/GSFC/Arizona State University
An image of the near side of the moon based on data from NASA's Lunar Reconnaissance Orbiter.
Soon, astronauts on moon missions won't have any excuse for not answering their texts.

NASA has awarded Nokia of America $14.1 million to deploy a cellular network on the moon. The freaking moon. The grant is part of $370 million worth of contracts signed under NASA's "Tipping Point" selections, meant to advance research and development for space exploration.

Nokia's plan is to build a 4G/LTE network, and eventually transition to 5G (just like the rest of us). It will be "the first LTE/4G communications system in space," according to NASA's announcement.

"The system could support lunar surface communications at greater distances, increased speeds, and provide more reliability than current standards," the announcement also reads.

Comment: See also:


Russian scientists create new biomaterial to restore bones for sufferers of osteoporosis

biomaterial osteoporosis Blue Mussel Shells
© NUST MISIS/Sergey Gnuskov
Scientists have synthesized surgery biomaterial from blue mussel shells
Researchers from Russia's Samara National Research University have created a biomaterial to restore bones, which could be revolutionary for the treatment of osteoporosis. The process uses a natural mineral called hydroxyapatite.

The research, published in the Russia-based medical journal 'Journal of Optical Technology' in March, has recently become known to the general public after a lead researcher spoke to Moscow news agency RIA Novosti. According to Elena Timchenko, a professor at the university, hydroxyapatites are currently used to restore the mineral components of bones, but the newly developed technology would also help restore organic components.

Comment: Sputnik adds:
Implant infections remain one of the main problems facing reconstructive surgery today. This problem can be solved by creating biomaterials with antibacterial activity, Evgeny Kolesnikov, the co-author of the study, a researcher at the Department of Functional Nanosystems and High-Temperature Materials at Russia's National University of Science and Technology (NUST/MISIS), says.
"Hydroxyapatite, the main mineral component of bones and teeth, is the top choice material to create new bone tissue or replace damaged bones. This material is biocompatible and bioactive; it can easily integrate into bone tissue and adjacent tissue areas. Hydroxyapatite is able to interact with osteoblasts, and positively induces their growth and division," he said.
Hydroxyapatite is currently used in maxillofacial surgery, dentistry and orthopaedics to make fillers and coatings. To produce hydroxyapatite, scientists from different countries use eggshells, coral, fish bones and other raw materials. However, its mass production is still a difficult task due to the complex process of synthesis.

A team of Indian, Russian, and South Korean scientists, headed by the former postdoctoral fellow and visiting professor at NUST/MISIS Dr. Gopalu Karunakaran announced that it may soon be possible to easily and quickly produce environmentally-friendly magnesium-doped mesoporous hydroxyapatite nanorods from biowaste, namely blue mussel shells (Mytilus edulis), through microwave synthesis using polyvinylpyrrolidone.

According to researchers, they have obtained hydroxyapatite particles that can be used in implantation. To prevent possible infections of the implant, these particles are laced with magnesium ions.

"We opted for magnesium because its ions are biocompatible and antimicrobial. The body of an average adult contains 24g of magnesium. A lack of this micro-element in the body can lead to diabetes, cardiovascular disease, hypertension and osteoporosis," Evgeny Kolesnikov explained.


Morphogenesis: How Nature codes for shape

Axolotl regeneration limbs morphogenesis
© Stan Shebs/Wikipedia
Ambystoma mexicanum (axolotl) at the Steinhart Aquarium in San Francisco
Organisms are hierarchies of shapes. Bacteria form rods, spirals, and spheres. Single-celled eukaryotes build diverse organelles inside and take on a characteristic shape outside (compare Stentor, Paramecium, and Amoeba). Think of all the varieties of shapes in multicellular organisms from Volvox to complex eukaryotes — hydra, rotifers, planaria at the microscopic end; crabs, octopuses, and beetles in the lower middle range; beavers, roses, and humans at the upper middle range; whales, sequoias, and brachiosaurs at the large end. Plants generate stems, leaves, and flowers. Animals grow tissues that organize into organs that combine into body plans. How do all these 3-D shapes emerge from a linear code? That is the puzzle of morphogenesis.

Comment: Dr Rupert Sheldrake, a specialist in developmental biology had some thoughts on the matter years ago:


Zeptoseconds: New world record in time measurement

In the global race to measure ever shorter time spans, physicists from Goethe University Frankfurt have now taken the lead: together with colleagues at the accelerator facility DESY in Hamburg and the Fritz-Haber-Institute in Berlin, they have measured a process that lies within the realm of zeptoseconds for the first time: the propagation of light within a molecule. A zeptosecond is a trillionth of a billionth of a second (10-21 seconds).
Schematic representation of zeptosecond measurement
© Sven Grundmann, Goethe University Frankfurt
Schematic representation of zeptosecond measurement. The photon (yellow, coming from the left) produces electron waves out of the electron cloud (grey) of the hydrogen molecule (red: nucleus), which interfere with each other (interference pattern: violet-white). The interference pattern is slightly skewed to the right, allowing the calculation of how long the photon required to get from one atom to the next.
In 1999, the Egyptian chemist Ahmed Zewail received the Nobel Prize for measuring the speed at which molecules change their shape. He founded femtochemistry using ultrashort laser flashes: the formation and breakup of chemical bonds occurs in the realm of femtoseconds. A femtosecond equals 0.000000000000001 seconds, or 10-15 seconds.

Now atomic physicists at Goethe University in Professor Reinhard Dörner's team have for the first time studied a process that is shorter than femtoseconds by magnitudes. They measured how long it takes for a photon to cross a hydrogen molecule: about 247 zeptoseconds for the average bond length of the molecule. This is the shortest timespan that has been successfully measured to date.


Lava lake rises at dangerous African volcano

Nyiragongo volcano
In a 2002 eruption, a lava lake within the crater of Nyiragongo volcano drained in hours.
In 2002, the last time Nyiragongo volcano erupted, lava raced down its flanks into the crowded city of Goma, on the border between the Democratic Republic of the Congo and Rwanda. About 250 people died, 20% of the city was destroyed, and hundreds of thousands fled. Since then, the at-risk population living in the shadow of the 3470-meter-tall volcano has more than doubled to 1.5 million.

Now, conditions are ripe for another disaster, says Dario Tedesco, a volcanologist at the Luigi Vanvitelli University of Campania, who earlier this year led a campaign into the volcano's roiling crater. He and his colleagues found the lava lake there filling at an alarming rate, raising the risk that the molten rock could burst through the crater walls once again. Their analysis suggests peak hazard will arrive in 4 years, although they believe an earthquake could trigger a crisis earlier. Adding to the concerns, the Goma Volcano Observatory (GVO), the only monitoring station in the region, is losing its financial support from the World Bank. Tedesco's assessment is blunt. "This is the most dangerous volcano in the world!"

Tedesco began to watch the volcano in the mid-1990s, when refugees, fleeing the genocide in nearby Rwanda, swelled Goma's population. The United Nations sought his advice on the dangers of the volcano, so he monitored Nyiragongo's moods in the years before the 2002 eruption. He is alarmed by parallels to today.

Microscope 1

World first study shows that some microorganisms can bend the rules of evolution

horizontal gene transfer
The dominant thinking in evolution focuses on inheritance between parent and offspring - or 'vertical gene transfer (VGT)'. But now scientists are paying more attention to 'horizontal gene transfer (HGT)': the transmission of DNA other than from parent to offspring, as this transfer can tell us about the evolution of a number of other organisms such as bacteria. It can also help us to better understand antibiotic resistance.

In a world first Monash University scientists have discovered that HGT can bend the rules of evolution.

The discovery is outlined in a study published today in PNAS, which was led by ARC Future Fellow Dr Mike McDonald and PhD candidate Laura Woods, both from the Monash University School of Biological Sciences.

Comment: The natural selection hypothesis continues to fall apart...

See also:


Study suggests psychopathic individuals do have emotions, but they are inept at regulating them

© Sammy-Williams from Pixabay
A study published in Psychiatry Research found that having psychopathic traits was linked to poor emotional regulation among both a community sample and a sample of violent offenders.

Psychopathy is a personality disorder that is defined by persistent antisocial behavior that is typically hostile, deviant, and apathetic. Although the study of psychopathy has captured the attention of researchers for some time, study authors Carlo Garofalo and colleagues observed a gap in the research.

Few studies have explored how difficulties in emotional regulation — the ability to monitor and control one's emotions — may be involved in the expression of psychopathy. One of the reasons for this disparity may be due to early definitions of psychopathy which suggested that psychopathic individuals were "devoid of emotion." Findings have since emerged suggesting that these individuals do, in fact, experience emotions.

"If psychopathy does not fundamentally involve an absence of emotions," Garofalo and team theorize, "it is possible that disturbances in emotional regulation may be linked to the expression of psychopathic traits."


'Twisted' bilayer graphene: The 'magic' material is now the big thing in physics

superconductor graphene layers
© Olena Shmahalo / Quanta Magazine.
Twisted bilayer graphene: a one-atom-thick sheet of carbon crystal dropped on another one
The stunning emergence of a new type of superconductivity with the mere twist of a carbon sheet has left physicists giddy, and its discoverer nearly overwhelmed.

Pablo Jarillo-Herrero is channeling some of his copious energy into a morning run, dodging startled pedestrians as he zips along, gradually disappearing into the distance. He'd doubtlessly be moving even faster if he weren't dressed in a sports coat, slacks and dress shoes, and confined to one of the many weirdly long corridors that crisscross the campus of the Massachusetts Institute of Technology. But what he lacks in gear and roadway he makes up for in determination, driven by the knowledge that a packed auditorium is waiting for him to take the podium.

Jarillo-Herrero has never been a slacker, but his activity has jumped several levels since his dramatic announcement in March 2018 that his lab at MIT had found superconductivity in twisted bilayer graphene — a one-atom-thick sheet of carbon crystal dropped on another one, and then rotated to leave the two layers slightly askew.