Hexbyte Glen Cove Keyhole wasps may threaten aviation safety thumbnail

Hexbyte Glen Cove Keyhole wasps may threaten aviation safety

Hexbyte Glen Cove

Pachodynerus nasidens on 3D-printed De Haviland Dash-8 pitot probe. Credit: House et al (2020) PLOS ONE, CC BY

Over a period of 39 months, invasive keyhole wasps (Pachodynerus nasidens) at the Brisbane Airport were responsible for 93 instances of fully blocked replica pitot probes—vital instruments that measure airspeed—according to a study published November 25 in the open-access journal PLOS ONE by Alan House of Eco Logical Australia and colleagues. As noted by the authors, the results underscore the importance of risk-mitigating strategies, such as covering pitot probes when aircraft arrive and setting up additional traps to intercept the wasps.

Interactions between aircraft and wildlife are frequent and can have serious financial and safety consequences. But the risk posed by wildlife when aircraft are on the ground is much less understood, and specific threats posed by insects have not been quantified before. In the new study, House and his colleagues investigated the possible role of keyhole in obstructing pitot probes at Brisbane Airport. A total of 26 wasp-related issues were reported at the between November 2013 and April 2019, in conjunction with a series of serious safety incidents involving pitot probes. In its native range in South and Central America and the Caribbean, the wasp is known to construct nests using man-made cavities, such as window crevices, electrical sockets, and of course, keyholes.

The researchers used 3-D-printing technology to construct a series of replica pitot probes, which they mounted at four locations at the airport. All nests in these probes were made by keyhole wasps, and peak nesting occurred in the summer months. Nesting success (i.e., the proportion of nests producing live adults) was optimal between 24 and 31°C, and probes with apertures of more than 3 mm in diameter were preferred. The majority of nests were constructed in one area of the airport. The proportion of grassed areas within 1000 m of probes was a significant predictor of nesting, and the volume in pitot probes may determine the sex of emerging wasps. According to the authors, P. nasidens poses a significant risk to , and further work is warranted to develop strategies for controlling or eradicating persistent populations of this adaptable, inventive, and highly mobile species.

The authors add: “We hope this research will bring attention to a little known but serious issue for air travel in tropical and sub-tropical regions. Having found its way across the Pacific Ocean, there is no reason to doubt that it could spread to other parts of Australia. The consequences of not managing this clever but dangerous pest could be substantial.”

More information:
House APN, Ring JG, Shaw PP (2020) Inventive nesting behaviour in the keyhole wasp Pachodynerus nasidens Latreille (Hymenoptera: Vespidae) in Australia, and the risk to aviation safety. PLoS ONE 15(11): e0242063. doi.org/10.1371/journal.pone.0242063

Keyhole wasps may threaten aviation safety (2020, November 26)
retrieved 26 November 2020
from https://phys.org/news/2020-11-keyhole-wasps-threaten-aviation-safety.html

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Hexbyte Glen Cove Pandemic postpones national math, reading tests until 2022 thumbnail

Hexbyte Glen Cove Pandemic postpones national math, reading tests until 2022

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Credit: CC0 Public Domain

National reading and math tests long used to track what U.S. students know in those subjects are being postponed from next year to 2022 over concerns about whether testing would be feasible or produce valid results during the coronavirus pandemic, the National Center for Education Statistics announced Wednesday.

The biennial National Assessment of Educational Progress evaluations used for the Nation’s Report Card were slated early next year for hundreds of thousands of the country’s fourth and eighth graders. But widespread remote learning and health protocols would have added big complications and costs because the model uses shared equipment and sends outside proctors to conduct the testing in schools.

Pushing ahead with testing in 2021 runs the risk of spending tens of millions of dollars and still not getting the data necessary to produce a reliable, comparable picture of state and national student performance, NCES Commissioner James Woodworth said in a statement. By law, they would have to wait another two years for the next chance at testing.

Testing in 2022 instead “would be more likely to provide valuable—and valid—data about student achievement in the wake of COVID-19 to support effective policy, research, and resource allocation,” the leaders of the National Assessment Governing Board said in a separate statement supporting the move.

The nonpartisan Council of Chief State School Officers also supported the NAEP postponement.

Ohio Department of Education spokesperson Mandy Minick called it “entirely understandable” given the extensive disruptions schools are facing.

“I think we’re all on the same page about trying to stress health and safety,” she said.

However, the decision also delays data that could help show how the pandemic is impacting learning.

Woodworth suggested that results from states’ annual tests—generally conducted using schools’ own equipment and staff, and perhaps therefore more feasible than the national tests—could help bridge the gap and provide a state-level look at the impact. But the NAEP postponement might have ripple effects in the debate about whether those state tests even happen in spring 2021.

State tests, which are federally mandated and are used more for accountability purposes, were canceled last spring under federal waivers as the pandemic surged. The current administration under Republican President Donald Trump had indicated states shouldn’t expect to be granted another round of waivers if they request them, but it’s an issue likely to come up again after Democratic President-elect Joe Biden’s administration takes office.

“If the national assessment can’t be done in ’21, states are legitimately going to say, ‘Well, why are we expected to test in ’21?'” said Chester Finn, a former chair of the National Assessment Governing Board and president emeritus of the Thomas B. Fordham Institute who advocates results-based accountability.

If states get to skip the tests again this spring, that could create a multiyear gap in data that helps inform other decisions and identify concerns, Finn said.

“If you’re not held accountable for your results, or there’s no way to do it because there’s no information about your results, then all sorts of bad things happen to the education system and to the kids in the education system,” he said. “We sort of go back to the pre-accountability days, when, you know, the only thing you knew about a kid’s learning was the teachers’ grades, and the only thing you knew about a school’s performance was what the principal said it was, and nobody had data on gaps between different groups of kids.”

The postponement of national tests is understandable but makes having state tests in 2021 “a moral imperative,” the chairman of the House Committee on Education and Labor, Rep. Bobby Scott, D-Va., and the top Democrat on the Senate Health, Education, Labor and Pensions Committee, Sen. Patty Murray of Washington state, said in a joint statement.

“In order for our nation to recover and rebuild from the pandemic, we must first understand the magnitude of learning loss that has impacted students across the country,” they wrote. “That cannot happen without assessment data.”

In letters to those lawmakers, Education Secretary Betsy DeVos also expressed strong support for proceeding with state assessments next spring and said states “have ample time to plan for successful administration tailored to their unique circumstances.”

Her letters also noted that because NAEP is federally mandated, Congress would need to sign off on postponing the national testing for a year.

© 2020 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.


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Hexbyte Glen Cove T. rex had huge growth spurts, but other dinos grew 'slow and steady' thumbnail

Hexbyte Glen Cove T. rex had huge growth spurts, but other dinos grew ‘slow and steady’

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Paleontologist Tom Cullen cutting into SUE the T. rex’s thigh bone to learn how T. rex grew. Credit: © David Evans

Tyrannosaurus rex was one of the biggest meat-eating dinosaurs of all time—it measured up to 42 feet long from snout to tail and would have weighed in at around 16,000 pounds. And it wasn’t alone—some of its less-well-known cousins could reach nearly the same size. Scientists have previously shown that T. rex got so big by going through a huge teenage growth spurt, but they didn’t know if that was true for just tyrannosaurs, just them and their close relatives, or perhaps all big bipedal dinosaurs. By cutting into dinosaur bones and analyzing the growth lines, a team of researchers got their answer: T. rex and its closest relatives had an awkward adolescence during which they got huge, while its more distant cousins in the allosauroid group kept on growing a little bit every year.

“We wanted to look at a wide swath of different theropods, two-legged, carnivorous , in order to understand broader patterns of growth and evolution in the group,” says Tom Cullen, the lead author of a new study in Proceedings of the Royal Society B.

Cullen, a scientific affiliate of Chicago’s Field Museum who worked on the study as a postdoctoral researcher at the Field with the museum’s then-curator of dinosaurs, Pete Makovicky, explains, “We particularly wanted to understand how some of them got so big—is the way T. rex grew the only way to do it?”

Makovicky, a scientific affiliate of the Field and professor of geology at the University of Minnesota and the paper’s senior author, says, “We also wanted to see if we got the same growth record when we sampled a variety of different bones from the same skeleton. All these questions about how theropods grew could impact our understanding of the evolution of the group.” Makovicky developed the idea for the project and also discovered several of the dinosaurs whose fossils were analyzed in the study.

The question of how an animal gets big is a surprisingly tricky one. Mammals like us tend to go through a period of extreme growth when we’re young and then stay the same size once we reach adulthood. In other animal groups, that’s not always the case. “Growth rate really varies, there’s no one size fits all,” says Cullen, who is now a postdoctoral researcher at the North Carolina Museum of Natural Sciences. “Birds have super growth spurts and reach adult size really fast, while reptiles like alligators and various lizards and snakes have extended growth. With them, a really, really big individual is probably really old.”

Theropod dinosaurs like T. rex are related to both modern birds and reptiles—in fact, birds are the only living theropods. Scientists didn’t know whether theropods’ growth patterns were more like those of birds or reptiles, and those different growth patterns can make a big difference in how an animal fits into its ecosystem. Getting big quickly can be a competitive advantage—it makes it easier for you to hunt other animals, and harder for other animals to hunt you. On the flip side, a growth spurt takes a lot of energy and resources, and it’s easier to just get a little bigger every year your whole life. “The amount of calories T. rex would have needed during its growth spurt would have been ridiculous,” says Cullen—like a teenage boy that ate dinosaurs instead of endless bags of bagel bites.

The central struggle in studying extinct animals is that we can never know exactly what their lives were like. Since we can’t directly observe a dinosaur growing the way you can a living animal today, it’s hard to know for sure how they grew. But there are clues in the fossil record that reveal growth patterns.

“”Inside the bones as an animal grows, there are markings like tree rings that record roughly how old the animal is, how much it’s growing each year, and a number of other factors,” says Cullen. To find these growth rings, Cullen and his colleagues sliced into fossils from dozens of dinosaurs, from ones the size of dogs and ostriches all the way up to SUE the T. rex, one of the biggest predatory dinosaurs ever discovered. Getting access to slice and dice bones from a range of theropods was not an easy proposition, but Cullen and Makovicky reached out to colleagues across the globe. In particular, they were able to get samples from a new species of giant carcharodontosaurid from Argentina as a direct counterpoint to T. rex—this specimen was discovered and excavated by Makovicky in collaboration with his Argentinean colleagues Juan Canale and Sebastian Apesteguía. The authors also reached out to colleagues at the Palaeontological Museum of Liaoning for samples of small theropods closely related to birds to get the evolutionarily broad sampling needed to determine large scale patterns in life history.

“The very first specimen that the Field Museum let me sample was SUE the T. rex,” says Cullen. “It was pretty nerve-wracking, since it’s such a famous fossil.” He used a diamond-tipped coring drill to cut a tiny cylinder out of SUE’s thigh bone. The resulting sample was a cross-section of SUE’s bone, with lines like tree rings showing where new bone had grown year after year. (The missing piece of bone, about the size of a D battery, was then filled in with brown putty—if you go see SUE at the Field Museum and look closely at their left thigh you might see it, but it’s hard to spot.)

Back in the lab, Cullen sliced samples of bone so thin that light could pass through them and examined them under a microscope.

“Most animals have a period every year when they stop growing, traditionally suggested to be in times like winter when food is more scarce. It shows up in the bones as a line, like a tree ring,” says Cullen. By analyzing these growth lines and examining the bones for new regions of growth, scientists can get a rough estimate of an animal’s age and how much it grew every year. There are also clues in the bone structure.

“You can see all the little areas where the bone cells have grown, and the structure of the blood vessels that passed through the bone,” says Cullen. “These vascular canals tell you roughly how fast the bone was growing. If the canals are more organized, the was being laid down more slowly, and if the structure is chaotic, it grew more quickly.”

Cullen found that the dinosaurs’ growth patterns depended on their family. T. rex and its relatives, the coelurosaurs, showed a period of extreme growth during adolescence, and then they petered out once they reached adulthood. SUE the T. rex lived to be about 33 years old, the oldest T. rex currently known, but reached their adult size by age 20. To reach this massive size, SUE probably gained around 35-45 pounds per week as a teenager. Their more distant cousins, the allosauroids, could reach sizes almost as big as T. rex, but they grew slowly throughout their whole lives, with the oldest individuals reaching the biggest sizes. Among the allosauroids they sampled was the new carcharodontosaur from Argentina. It reached a size close to that of SUE, but didn’t reach adult size until its 30s to 40s. It lived to be up to about 50 years old or more, making it the oldest individual theropod on record aside from some birds like parrots. Despite its advanced age, it had only stopped growing 2 or 3 years before becoming part of the fossil record.

The discovery opens up questions about how these predatory dinosaurs interacted with the animals around them. The plant-eating dinosaurs that lived alongside T. rex were ceratopsians like Triceratops and duck-billed hadrosaurs. They grew extremely quickly in adolescence too. The slow-growing allosauroid carnivores lived with big long-necked sauropods that also grew quickly, but appear to have taken a long time to reach full size. Those trends might be related.

“We can’t say for sure, but there could be some kind of a selection pressure for the coelurosaurs to grow quickly to keep up with their prey, or pressure for the allosauroids to keep growing in size since their prey were also increasing in size,” says Cullen. “But it’s pretty speculative. It could be that even if the sauropods kept growing their whole lives, they had so many offspring that there was always something small to eat.”

But while the research hasn’t answered all the questions about why dinosaurs like T. rex grew the way they did, Cullen says, “I’m really proud of this work. It’s the culmination of many, many years of small projects building towards sort of a central goal of trying to understand growth in these animals and understand the many factors that influence these patterns. This doesn’t r