It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Thursday, August 18, 2022
Study confirms that speculation taxes are not an effective tool in curbing house prices
As the Ontario housing market enters a potentially volatile phase, new research from the University of Waterloo shows how tax policy has proven ineffective in controlling prices.
The report specifically looked at market behaviour of the nine largest Ontario population centres between 2011 and 2021 — a time of significant price increases across the province.
“Every city in Ontario hopes to regulate its own housing market as part of its duty to its citizens,” said Olaf Weber, a researcher in Waterloo’s School of Environment, Enterprise, and Development. “We found that quite often such policies are ineffective partially due to factors out of their control.”
The study points to how both geography and our three-tiered governance system both play a role in diminishing municipal efforts to regulate housing prices with taxation. For instance, speculation taxes, such as Ontario Non-Resident Speculation Tax, rarely dissuades large-scale investors from purchasing property and leaving it vacant.
“This phenomenon is most present in the largest cities, and taxes like these really only represent a marginal change in profits for most large investors,” Weber said. “They’ll either pay the tax, or they’ll move to the next closest city and buy there.”
The researchers call this the “spillover effect.” “Cities like Toronto are so desirable there is very little they can do to regulate their market, and are so big, neighbouring cities are at the mercy of what happens there,” Weber said.
According to the study, changes to other tax-related measures such as land-transfer taxes, and property taxes, have also proven to be largely ineffective in curbing prices as any stability from the well-intentioned measures can be wiped out by an interest rate change at the federal level, or a policy change provincially.
“Municipalities are frustrated,” Weber said. “I am not sure what they can do when so many factors are playing against each other. Empirically, the only thing that has worked to create affordable housing is when cities buy, build, or manage properties themselves and set the price.”
The study, authored by Weber and PhD student Muhammad Adil Rauf also of Waterloo’s Faculty of Environment, was recently published in the journal Sustainability.
JOURNAL
Sustainability
One more clue to the Moon's origin
Date: August 10, 2022
Source: ETH Zurich
Summary:
Researchers discover the first definitive proof that the Moon inherited indigenous noble gases from the Earth's mantle. The discovery represents a significant piece of the puzzle towards understanding how the Moon and, potentially, the Earth and other celestial bodies were formed.
Humankind has maintained an enduring fascination with the Moon. It was not until Galileo's time, however, that scientists really began study it. Over the course of nearly five centuries, researchers put forward numerous, much debated theories as to how the Moon was formed. Now, geochemists, cosmochemists, and petrologists at ETH Zurich shed new light on the Moon's origin story. In a study just published in the journal, Science Advances, the research team reports findings that show that the Moon inherited the indigenous noble gases of helium and neon from Earth's mantle. The discovery adds to the already strong constraints on the currently favoured "Giant Impact" theory that hypothesizes the Moon was formed by a massive collision between Earth and another celestial body.
Meteorites from the Moon to Antarctica
During her doctoral research at ETH Zurich, Patrizia Will analysed six samples of lunar meteorites from an Antarctic collection, obtained from NASA. The meteorites consist of basalt rock that formed when magma welled up from the interior of the Moon and cooled quickly. They remained covered by additional basalt layers after their formation, which protected the rock from cosmic rays and, particularly, the solar wind. The cooling process resulted in the formation of lunar glass particles amongst the other minerals found in magma. Will and the team discovered that the glass particles retain the chemical fingerprints (isotopic signatures) of the solar gases: helium and neon from the Moon's interior. Their findings strongly support that the Moon inherited noble gases indigenous to the Earth. "Finding solar gases, for the first time, in basaltic materials from the Moon that are unrelated to any exposure on the lunar surface was such an exciting result," says Will.
Without the protection of an atmosphere, asteroids continually pelt the Moon's surface. It likely took a high-energy impact to eject the meteorites from the middle layers of the lava flow similar to the vast plains known as the Lunar Mare. Eventually the rock fragments made their way to Earth in the form of meteorites. Many of these meteorite samples are picked up in the deserts of North Africa or in, in this case, the "cold desert" of Antarctica where they are easier to spot in the landscape.
Grateful Dead lyrics inspire lab instrument
In the Noble Gas Laboratory at ETH Zurich resides a state-of-the-art noble gas mass spectrometer named, "Tom Dooley" -- sung about in the Grateful Dead tune by the same name. The instrument got its name, when earlier researchers, at one point, suspended the highly sensitive equipment from the ceiling of the lab to avoid interference from the vibrations of everyday life. Using the Tom Dooley instrument, the research team was able to measure sub-millimetre glass particles from the meteorites and rule out solar wind as the source of the detected gases. The helium and neon that they detected were in a much higher abundance than expected.
The Tom Dooley is so sensitive that it is, in fact, the only instrument in the world capable of detecting such minimal concentrations of helium and neon. It was used to detect these noble gases in the 7 billion years old grains in the Murchison meteorite -- the oldest known solid matter to-date. Searching for the origins of life
Knowing where to look inside NASA's vast collection of some 70,000 approved meteorites represents a major step forward. "I am strongly convinced that there will be a race to study heavy noble gases and isotopes in meteoritic materials," says ETH Zurich Professor Henner Busemann, one of the world's leading scientists in the field of extra-terrestrial noble gas geochemistry. He anticipates that soon researchers will be looking for noble gases such as xenon and krypton which are more challenging to identify. They will also be searching for other volatile elements such as hydrogen or halogens in the lunar meteorites.
Busemann comments, "While such gases are not necessary for life, it would be interesting to know how some of these noble gases survived the brutal and violent formation of the moon. Such knowledge might help scientists in geochemistry and geophysics to create new models that show more generally how such most volatile elements can survive planet formation, in our solar system and beyond."
Story Source:
Materials provided by ETH Zurich. Original written by Marianne Lucien. Note: Content may be edited for style and length.
Journal Reference:Patrizia Will, Henner Busemann, My E. I. Riebe, Colin Maden. Indigenous noble gases in the Moon’s interior. Science Advances, 2022; 8 (32) DOI: 10.1126/sciadv.abl4920
Evidence that giant meteorite impacts created the continents
Date: August 10, 2022
Source: Curtin University
Summary:
New research has provided the strongest evidence yet that Earth's continents were formed by giant meteorite impacts that were particularly prevalent during the first billion years or so of our planet's four-and-a-half-billion year history.
New Curtin research has provided the strongest evidence yet that Earth's continents were formed by giant meteorite impacts that were particularly prevalent during the first billion years or so of our planet's four-and-a-half-billion year history.
Dr Tim Johnson, from Curtin's School of Earth and Planetary Sciences, said the idea that the continents originally formed at sites of giant meteorite impacts had been around for decades, but until now there was little solid evidence to support the theory.
"By examining tiny crystals of the mineral zircon in rocks from the Pilbara Craton in Western Australia, which represents Earth's best-preserved remnant of ancient crust, we found evidence of these giant meteorite impacts," Dr Johnson said.
"Studying the composition of oxygen isotopes in these zircon crystals revealed a 'top-down' process starting with the melting of rocks near the surface and progressing deeper, consistent with the geological effect of giant meteorite impacts.
"Our research provides the first solid evidence that the processes that ultimately formed the continents began with giant meteorite impacts, similar to those responsible for the extinction of the dinosaurs, but which occurred billions of years earlier."
Dr Johnson said understanding the formation and ongoing evolution of the Earth's continents was crucial given that these landmasses host the majority of Earth's biomass, all humans and almost all of the planet's important mineral deposits.
"Not least, the continents host critical metals such as lithium, tin and nickel, commodities that are essential to the emerging green technologies needed to fulfil our obligation to mitigate climate change," Dr Johnson said.
"These mineral deposits are the end result of a process known as crustal differentiation, which began with the formation of the earliest landmasses, of which the Pilbara Craton is just one of many.
"Data related to other areas of ancient continental crust on Earth appears to show patterns similar to those recognised in Western Australia. We would like to test our findings on these ancient rocks to see if, as we suspect, our model is more widely applicable."
Dr Johnson is affiliated with The Institute for Geoscience Research (TIGeR), Curtin's flagship earth sciences research institute.
The paper, 'Giant impacts and the origin and evolution of continents', was published in Nature.
Journal Reference:Tim E. Johnson, Christopher L. Kirkland, Yongjun Lu, R. Hugh Smithies, Michael Brown, Michael I. H. Hartnady. Giant impacts and the origin and evolution of continents. Nature, 2022; 608 (7922): 330 DOI: 10.1038/s41586-022-04956-y
New 3D model shows: Megalodon could eat prey the size of entire killer whales
The reconstructed megadolon (Otodus megalodon) was 16 meters long and weighed over 61 tons. It was estimated that it could swim at around 1.4 meters per second. Credit: J.J.Giraldo
The reconstructed megalodon (Otodus megalodon) was 16 meters long and weighed more than 61 tons. It was estimated that it swam at around 1.4 meters per second, required over 98,000 kilo calories every day and had a stomach volume of almost 10,000 liters. These results suggest that the megalodon could travel long distances and was capable of eating whole prey up to 8 meters long. Notably, this is the size of modern killer whales, today's top ocean predator. An ability to eat large apex predators of comparable size millions of years ago places megalodon at a higher trophic level than modern top predators.
Well-preserved spine enables reconstruction
These are the findings of an international study published in Science Advances and carried out in collaboration with the University of Zurich. The research was only possible thanks to the 3D modeling of one individual megalodon that was discovered in the 1860s. Against all odds, a sizeable portion of its vertebral column was left behind in the fossil record after the creature died in the Miocene oceans of Belgium at the age of 46 about 18 million years ago.
"Shark teeth are common fossils because of their hard composition which allows them to remain well preserved," says first author Jack Cooper, Ph.D. student at Swansea University. "However, their skeletons are made of cartilage, so they rarely fossilize. The megalodon vertebral column from the Royal Belgian Institute of Natural Sciences is therefore a one-of-a-kind fossil."
From single vertebra to whole body mass
The research team, which includes researchers from Switzerland, U.K., U.S., Australia and South Africa, first measured and scanned every single vertebra, before reconstructing the entire column. They then attached the column to a 3D scan of a megalodon's dentition from the United States. They completed the model by adding "flesh" around the skeleton using a 3D-scan of the body of a great white shark from South Africa.
"Weight is one of the most important traits of any animal. For extinct animals we can estimate the body mass with modern 3D digital modeling methods and then establish the relationship between mass and other biological properties such as speed and energy usage," says co-author John Hutchinson, professor at the Royal Veterinary College in the U.K.
A trans-oceanic super-apex predator
The high energetic demand would have been met by feeding on calorie-rich blubber of whales, in which megalodon bite marks have previously been found in the fossil record. An optimal foraging model of potential megalodon prey encounters found that eating a single 8-meter-long whale may have allowed the shark to swim thousands of miles across oceans without eating again for two months.
"These results suggest that this giant shark was a trans-oceanic super-apex predator," says Catalina Pimiento, Professor at the University of Zurich and senior author of the study. "The extinction of this iconic giant shark likely impacted global nutrient transport and released large cetaceans from a strong predatory pressure."
The complete model can now be used as a basis for future reconstructions and further research. The novel biological inferences drawn from this study represent a leap in our knowledge of this singular super predator and helps to better understand the ecological function that megafaunal species play in marine ecosystems, and the large-scale consequences of their extinction.New analyses of giant fossilized megalodon teeth are helping scientists unravel the mystery of their extinction
Climate change could make heat waves a dangerous hazard of future hurricanes. Credit: U.S. Navy / Mass Communication Specialist 1st Class R. Jason Brunson / Released
As Earth warms due to climate change, people living near the coasts not only face a higher risk of major hurricanes, but are also more likely to experience a subsequent heat wave while grappling with widespread power outages.
Princeton researchers have investigated the risk of this compound hazard occurring in the future under a "business-as-usual" climate scenario, using Harris County, Texas, as an example. They estimated that the risk of undergoing at least one hurricane-blackout-heat wave lasting more than five days in a 20-year span would increase 23 times by the end of the century. But there is some good news: Strategically burying just 5% of power lines—specifically those near main distribution points—would almost halve the number of affected residents.
Heat waves are the deadliest type of weather event and can become even more dangerous when regions that rely on air conditioning lose power. Historically, a heat wave following a hurricane has been rare, because the risk of extreme heat usually passes before the peak of the Atlantic hurricane season in late summer. As global temperatures rise, however, heat waves are expected to occur more often and hurricanes are likely to become more common and more severe, increasing the odds of hurricane-blackout-heat wave events.
"Hurricane Laura in 2020 and Hurricane Ida in 2021 both had heat waves following them after they destroyed the power distribution network," said Ning Lin, associate professor of civil and environmental engineering, who led the study. "For this compound hazard, the risk has been increasing, and it is now happening."
In a new study, published July 30 in Nature Communications, Lin and her coauthors looked at the risks associated with the compound hazard and how infrastructure changes could mitigate the potentially deadly effects. They combined projections of how often and when hurricanes and heat waves would strike in the future with estimates of how quickly power could be restored in areas with outages after a major storm.
The team chose Harris—the home of Houston—as their model county because it has the highest population density of any city on the Gulf Coast. Hurricanes Harvey and Ike both walloped Houston, causing an estimated 10% of residents to lose power.
The researchers found that the percentage of Harris residents expected to experience at least one hurricane-blackout-heat wave longer than five days within two decades would grow from a present risk of 0.8% to a future risk of 18.2% by the end of the century. Different parts of the county will likely suffer more than others, however, with rural residents facing a higher risk of extended outages.
The team also considered power grid improvements that would reduce the impact of a hurricane-blackout-heat wave for residents. Burying 5% of wires near the roots of the distribution network would reduce the expected percentage of residents without power from 18.2% to 11.3%.
"Mostly, our current practice is randomly burying lines," Lin said. "By burying lines more strategically, we can be more efficient and more effective at reducing the risk."
This type of analysis can help city planners understand where residents will be most at risk of a hurricane-blackout-heat wave and to identify targeted improvements to their power distribution system that can best diminish the impact.
"This is a very important work," said Lei Zhao, an assistant professor in the Department of Civil and Environmental Engineering at the University of Illinois Urbana-Champaign who was not involved with the research. "This paper not only provides the projections; it connects the extremes with real-world impacts."
He said that one take-home message from the work is that climate modelers, engineers and city planners need to work together to mitigate the risks faced by the almost 30% of the U.S. population that lives in coastal counties. "Nowadays, we encounter some extremes almost every year," he said. "People are realizing it's not just infrastructure design, it needs to be climate-informed infrastructure design."
The current study examines the problem of compound hazards at the county level, but Lin's group is working to scale up the analysis to entire states. They are looking for ways to reduce the computational demands of the analysis, because as they expand the geographic area, physics-based power system modeling becomes computationally taxing.
More generally, the new work highlights the need to think about the intersections of different hazards and how they may worsen under climate change.
"Climate can drive multiple hazards with compound effects that we don't understand, and that may be new to us in the future," Lin said. "Considering this kind of compounding of multiple climate hazards and infrastructure vulnerability is an important direction both for the research community and for decision-making."Extreme heat is getting worse. Is North Carolina's power grid ready?
More information:Kairui Feng et al, Tropical cyclone-blackout-heatwave compound hazard resilience in a changing climate,Nature Communications(2022).DOI: 10.1038/s41467-022-32018-4
Using light, atoms can be made to attract each other. A team from Vienna and Innsbruck was able to measure this binding state of light and matter for the first time
IMAGE: THE ATOMS ARE POLARIZED BY THE BEAM OF LIGHT AND START TO ATTRACT EACH OTHER.view more
CREDIT: HARALD RITSCH / TU WIEN
Theoretically, this effect has been predicted for a long time, but now scientists at the Vienna Center for Quantum Science and Technology (VCQ) at TU Wien, in cooperation with the University of Innsbruck, have succeeded in measuring this exotic atomic bond for the first time. This interaction is useful for manipulating extremely cold atoms, and the effect could also play a role in the formation of molecules in space. The results have now been published in the scientific journal Physical Review X.
Positive and negative charge
In an electrically neutral atom, a positively charged atomic nucleus is surrounded by negatively charged electrons, which surround the atomic nucleus much like a cloud. "If you now switch on an external electric field, this charge distribution shifts a little," explains Prof. Philipp Haslinger, whose research at the Atominstitut at TU Wien is supported by the FWF START programme. "The positive charge is shifted slightly in one direction, the negative charge slightly in the other direction, the atom suddenly has a positive and a negative side, it is polarised."
Light is just an electromagnetic field that changes very rapidly, so it is also possible to create this polarisation effect with laser light. When several atoms are next to each other, the laser light polarises them all in exactly the same way – positive on the left and negative on the right, or vice versa. In both cases, two neighbouring atoms turn different charges towards each other, leading to an attractive force.
Experiments with the atom trap
"This is a very weak attractive force, so you have to conduct the experiment very carefully to be able to measure it," says Mira Maiwöger from TU Wien, the first author of the publication. "If atoms have a lot of energy and are moving quickly, the attractive force is gone immediately. This is why a cloud of ultracold atoms was used."
The atoms are first captured and cooled in a magnetic trap on an atom chip, a technique, which was developed at the Atominstitut in the group of Prof. Jörg Schmiedmayer. Then the trap is switched off and releases the atoms in free fall. The atom cloud is 'ultracold' at less than a millionth of a Kelvin, but it has enough energy to expand during the fall. However, if the atoms are polarized with a laser beam during this phase and thus an attractive force is created between them, this expansion of the atomic cloud is slowed down - and this is how the attractive force measured.
Quantum laboratory and space
"Polarising individual atoms with laser beams is basically nothing new," says Matthias Sonnleitner, who laid the theoretical foundation for the experiment. "The crucial thing about our experiment, however, is that we have succeeded for the first time in polarising several atoms together in a controlled way, creating a measurable attractive force between them."
This attractive force is a complementary tool for controlling cold atoms. But it could also be important in astrophysics: "In the vastness of space, small forces can play a significant role," says Philipp Haslinger. "Here, we were able to show for the first time that electromagnetic radiation can generate a force between atoms, which may help to shed new light on astrophysical scenarios that have not yet been explained."
Like it or not, bumps and bruises are an unavoidable part of childhood. But while no parent wants their child to feel pain, teaching children about pain when they’re young can help them better understand and respond to pain when they’re older.
In a new study from the University of South Australia researchers identified five key approaches that parents and caregivers can use when talking with young children about ‘everyday’ pain, and that can help their recovery and resilience after injury.
In this study, researchers investigated ‘everyday’ pains in young children (aged 2-7 years-old), asking experts from child health, psychology, development, resilience, as well as parents and educators, what they thought would promote children’s recovery and resilience after minor pains or injury.
With 80 per cent consensus across all experts, the most important messages were to:
Teach children about the meaning of pain – pain is our body’s alarm system.
Validate children’s pain – ensure they feel safe, heard, and protected, but don’t make a fuss.
Reassure children after an injury - let them know that their body will heal, and the pain will pass.
Support children’s emotions – let them express themselves but encourage them to regulate.
Involve children in their recovery – encourage them to manage their pain (eg. get a bandaid).
Lead researcher, UniSA’s Dr Sarah Wallwork, says parents and caregivers likely play a critical role in helping children learn about pain.
“Whether it’s falling from a bike or dealing with the often-dreaded vaccinations, everyday pain experiences are opportunities for parents to promote positive pain-related beliefs and behaviours,” Dr Wallwork says.
“While it’s important to teach children that pain is our body’s alarm system and that it’s there to protect us, it’s equally important to understand that pain and injury do not always align.
“As adults, one of the greatest pain management challenges is that we hold fundamental, life-long beliefs about how pain and recovery works. Often, when we get an injury, we believe that pain must follow; and conversely, if we feel pain, then we must have an injury - but as research shows, this isn’t always the case.
“In children, pain can be influenced by their emotions – for example, fear, hunger, or tiredness can exacerbate symptoms, even though this is not pain itself.
“Teaching children that they can have some control over their pain - and that how they feel on the inside can influence this - empowers them to actively engage with their own pain management.
“This can be age-appropriate too. So, for a very young child, empowerment might be getting a bandaid or a wet cloth, rubbing the area and distracting them, then telling them their injury is protected by the bandaid and that it is now safe to move on and play. For an older child, the process can be more involved.
“The key is to demonstrate that the child is the healer and they that are actively involved in the healing process.
“By helping children learn about pain when they are young, we’re hoping to promote lifelong ‘helpful’ pain behaviours that will actively encourage recovery and prevent future pain problems.”
Communicating with children about ‘everyday’ pain and injury: A Delphi study
COI STATEMENT
GLM has received support from: Reality Health, ConnectHealth UK, Kaiser Permanente, AIA Australia, Workers' Compensation Boards and professional sport-ing organizations in Australia, Europe and South and North America. Professional and scientific bodies have reimbursed him for travel costs related to presentation of research on pain at scientific conferences/symposia. He has received speaker fees for lectures on pain and rehabilitation. He receives royalties for books on pain and pain education. SBW and MN have no conflicts of interest.
A pioneering project to develop advanced sensors for use in robotic systems, could transform prosthetics and robotic limbs.
The research project – led by University of the West of Scotland (UWS), Integrated Graphene Ltd, and supported by the Scottish Research Partnership in Engineering (SRPe) and the National Manufacturing Institute for Scotland (NMIS) Industry Doctorate Programme in Advanced Manufacturing – aims to develop sensors which provide enhanced capabilities to robots, helping improve their dexterity and motor skills, through the use of accurate pressure sensors which provide haptic feedback and distributed touch.
Professor Des Gibson, Director of the Institute of Thin Films, Sensors and Imaging at UWS and project principal investigator, said: “Over recent years the advancements in the robotics industry have been remarkable, however, due to a lack of sensory capabilities, robotic systems often fail to execute certain tasks easily. For robots to reach their full potential, accurate pressure sensors, capable of providing greater tactile ability, are required.
“Our collaboration with Integrated Graphene Ltd, has led to the development of advanced pressure sensor technology, which could help transform robotic systems.”
Made from 3D graphene foam, which offers unique capabilities when put under mechanical stress, the sensors use a piezoresistiveapproach, meaning when the material is put under pressure it dynamically changes its electric resistance, easily detecting and adapting to the range of pressure required, from light to heavy.
Marco Caffio, co-founder and Chief Scientific Officer at Integrated Graphene said: “Gii, our novel 3D graphene foam, has the capability to mimic the sensitivity and feedback of human touch, which could have a transformative impact on how robotics can be used for a whole range of real-world applications from surgery to precision manufacturing.
“We know the unique property of Gii makes it suitable for use in other applications like disease diagnostics and energy storage, so we’re always very excited to be able to demonstrate its flexibility in projects like this one.”
Dr Carlos Garcia Nunez, School of Computing Engineering and Physical Sciences at UWS added: “Within robotics and wearable electronics the use of pressure sensors is a vital element, to provide either an information input system, or to give robotic systems human-like motor skills. An advanced material like 3D graphene foam offers excellent potential for use in such applications, due to its outstanding electrical, mechanical and chemical properties.
“Our work shines a light on the significant potential for this technology to revolutionise the robotics industry with dynamic pressure sensors.”
Claire Ordoyno, Interim Director of SRPe, added: “The SRPe - NMIS Industrial Doctorate Programme brings together ground breaking academic research with industry partners to drive forward innovation in engineering. These collaborative PhD projects not only enhance the Scottish engineering research landscape, but produce innovation focussed, industry ready PhD graduates to feed the talent pipeline.”
The next stage of the project – funded by UWS, Integrated Graphene Ltd, SRPe and NMIS – will look to further increase sensitivity of the sensors, before developing for wider use in robotic systems.
IMAGE: ECOLOGICAL RECONSTRUCTION OF K. POPOVI.view more
CREDIT: NIGPAS
Parental care refers to the protection, care and feeding of eggs or offspring by parents. It has evolved independently multiple times in animals, e.g., mammals, birds, dinosaurs, arthropods, and especially various lineages of social insects.
Brood care is a form of uniparental care where parents carry eggs or juveniles after oviposition and provide protection, enhancing offspring fitness and survival. However, very few fossil insects directly document such ephemeral behavior. Among Mesozoic insects, the only two direct fossil cases of brooding ethology are from the Early Cretaceous Jehol Biota and mid-Cretaceous Burmese amber.
Recently, a research group led by Prof. HUANG Diying from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) systematically studied the water boatman Karataviella popovi, a representative insect from the Middle-Late Jurassic Daohugou Biota of northeastern China. Of the 157 examined K. popovi fossils, 30 adult females were preserved with a cluster of eggs anchored on their left mesotibia.
This discovery represents the earliest direct evidence of brood care among insects, indicating that relevant adaptations associated with maternal investment in insects can be traced back to at least the Middle Jurassic, pushing back by approximately 40 million years evidence of such behavior.
The true water bug superfamily Corixoidea, commonly known as the water boatman, is a common aquatic Hemipteran insect and occurs in various freshwater ecosystems worldwide. Extant water boatmen commonly deposit eggs on various subaquatic substances such as leaves or stems of aquatic vegetation, stones, and even on snail shells, carapaces of terrapins, and the exoskeletons of crayfish.
The Jurassic water boatman K. popovi from the Daohugou Biota has a relatively large body, with body length ranging from 11-15 mm.
The specialized protarsi of K. popovi, combined with the five patches of setae on the head that form a trawl-like feeding apparatus, reflect highly specialized predatory behavior. Anostracans and the water boatman K. popovi, both found in the same layer of the Daohugou beds, represent precursors and dominators, respectively.
After the analysis of more than 700 anostracan eggs, the researchers hypothesized that the abundant seasonally produced anostracan eggs in the Daohugou Biota probably were the food source for K. popovi.
The egg clusters of K. popovi are compact and arranged in approximately five to six staggered rows, attached to and throughout the left mesotibia of adult females by short egg stalks. As inferred from the arrangement of the eggs, each row seems to have six to seven eggs. The diameters of eggs (without stalks) range from 1.14 to 1.20 mm.
"Due to the potential high predation risk caused by abundant salamanders in the Daohugou Biota and seasonal food resources, K. popovi may have been exposed to fierce ecological pressure in the Daohugou Biota," said Prof. HUANG.
The brooding behavior developed in K. popovi probably reflected adaptations to habitat or an evolutionary response to changes in the ancient lake ecosystem. The brooding behavior of K. popovi most likely provided effective protection for eggs by largely avoiding the risks of predation, desiccation and hypoxia. Such behavior had important effects on its evolution, development and reproductive success.
To our knowledge, carrying a cluster of eggs on a leg is a unique strategy among insects. However, it is not unusual in aquatic arthropods, where such carrying behaviour can be traced back to the early Cambrian Chengjiang Biota.
This discovery highlights the existence of diverse brooding strategies in Mesozoic insects, thus helping scientists understand the evolution and adaptive significance of brood care in insects.
CAPTION
Morphological characterstics of K. popovi.
CREDIT
NIGPAS
CAPTION
Brooding in K. popovi
CREDIT
NIGPAS
CAPTION
Specialized filter-capture apparatus in K. popovi
CREDIT
NIGPAS
JOURNAL
Proceedings of the Royal Society B Biological Sciences
IMAGE: THIS ILLUSTRATION MODELS THE TOPOGRAPHY (IN METERS) OF CERES FROM NASA’S DAWN PROJECT, WITH GREEN AND BLUE COLORS. SOME OF THE DWARF PLANET’S MAJOR CRATERS ARE LABELED. A RULER IS BELOW THE IMAGE OF CERES SHOWING, IN METERS, NEGATIVE 8,000 TO POSITIVE 8,000.view more
CREDIT: VIRGINIA TECH
For a long time, our view of Ceres was fuzzy, said Scott King, a geoscientist in the Virginia Tech College of Science. A dwarf planet and the largest body found in the asteroid belt — the region between Jupiter and Mars speckled with hundreds of thousands of asteroids — Ceres had no distinguishable surface features in existing telescopic observations from Earth.
Then, in 2015, the hazy orb that was Ceres came into view. That view was stunning to scientists such as King. Data and images collected by NASA’s Dawn mission gave a clearer picture of the surface, including its composition and structures, which revealed unexpected geologic activity.
Scientists had seen the general size of Ceres in earlier observations. It was so small it was assumed to be inactive. Instead, Dawn discovered a large plateau on one side of Ceres that covered a fraction of the dwarf planet, similar to what a continent might take up on Earth. Surrounding it were fractures in rocks clustered in one location. And there were visible traces of an ocean world: deposits all over the surface where minerals had condensed as water evaporated — the mark of a freezing ocean.
A professor in the Department of Geosciences, King, who mostly studies larger bodies such as planets, wanted to know how a body as small as Ceres could generate the heat needed to power that kind of geological activity and account for the surface features picked up by Dawn.
Through modeling, he and a team of scientists from multiple universities as well as the United States Geological Survey and the Planetary Science Institute found that the decay of radioactive elements within Ceres’s interior could keep it active. Their findings were recently published in American Geophysical Union Advances.
King’s study of big planets such as Earth, Venus, and Mars had always shown him that planets start out hot. The collision between objects that form a planet creates that initial heat. Ceres, by contrast, never got big enough to become a planet and generate heat the same way, King said. To learn how it could still generate enough heat to power geologic activity, he used theories and computational tools previously applied to bigger planets to study Ceres’s interior, and he looked for evidence that could support his models in data returned by the Dawn mission.
The team’s model of the dwarf planet’s interior showed a unique sequence: Ceres started out cold and heated up because of the decay of radioactive elements such as uranium and thorium — which was alone enough to power its activity — until the interior became unstable.
“What I would see in the model is, all of a sudden, one part of the interior would start heating up and would be moving upward and then the other part would be moving downward,” King said.
That instability could explain some of the surface features that had formed on Ceres, as revealed by the Dawn mission. The large plateau had formed on only one side of Ceres with nothing on the other side, and the fractures were clustered in a single location around it. The concentration of features in one hemisphere signaled to King that instability had occurred and had left a visible impact.
“It turned out that you could show in the model that where one hemisphere had this instability that was rising up, it would cause extension at the surface, and it was consistent with these patterns of fractures,” King said.
Based on the team’s model, Ceres didn’t follow a planet’s typical pattern of hot first and cool second, with its own pattern of cool, hot, and cool again. “What we’ve shown in this paper is that radiogenic heating all on its own is enough to create interesting geology,” King said.
He sees similarities to Ceres in the moons of Uranus, which a study commissioned by NASA and the National Science Foundation recently deemed high priority for a major robotic mission. With additional improvements to the model, he looks forward to exploring their interiors as well.
“Some of these moons are not too different in size from Ceres,” King said. “I think applying the model would be really exciting.”
