Eyes wide shut: How newborn mammals dream the world they're entering

Date:July 22, 2021

Source:Yale University

Summary:

As a newborn mammal opens its eyes for the first time, it can already make visual sense of the world around it. But how does this happen before they have experienced sight?Share:



Mother mouse with young (stock image).
Credit: © tilialucida / stock.adobe.com

As a newborn mammal opens its eyes for the first time, it can already make visual sense of the world around it. But how does this happen before they have experienced sight?

A new Yale study suggests that, in a sense, mammals dream about the world they are about to experience before they are even born.

Writing in the July 23 issue of Science, a team led by Michael Crair, the William Ziegler III Professor of Neuroscience and professor of ophthalmology and visual science, describes waves of activity that emanate from the neonatal retina in mice before their eyes ever open.

This activity disappears soon after birth and is replaced by a more mature network of neural transmissions of visual stimuli to the brain, where information is further encoded and stored.

"At eye opening, mammals are capable of pretty sophisticated behavior," said Crair, senior author of the study, who is also vice provost for research at Yale." But how do the circuits form that allow us to perceive motion and navigate the world? It turns out we are born capable of many of these behaviors, at least in rudimentary form."

In the study, Crair's team, led by Yale graduate students Xinxin Ge and Kathy Zhang, explored the origins of these waves of activity. Imaging the brains of mice soon after birth but before their eyes opened, the Yale team found that these retinal waves flow in a pattern that mimics the activity that would occur if the animal were moving forward through the environment.

"This early dream-like activity makes evolutionary sense because it allows a mouse to anticipate what it will experience after opening its eyes, and be prepared to respond immediately to environmental threats," Crair noted.

Going further, the Yale team also investigated the cells and circuits responsible for propagating the retinal waves that mimic forward motion in neonatal mice. They found that blocking the function of starburst amacrine cells, which are cells in the retina that release neurotransmitters, prevents the waves from flowing in the direction that mimics forward motion. This in turn impairs the development of the mouse's ability to respond to visual motion after birth.

Intriguingly, within the adult retina of the mouse these same cells play a crucial role in a more sophisticated motion detection circuit that allows them to respond to environmental cues.

Mice, of course, differ from humans in their ability to quickly navigate their environment soon after birth. However, human babies are also able to immediately detect objects and identify motion, such as a finger moving across their field of vision, suggesting that their visual system was also primed before birth.

"These brain circuits are self-organized at birth and some of the early teaching is already done," Crair said. "It's like dreaming about what you are going to see before you even open your eyes."


Related Multimedia:
YouTube video: Retinal Waves in Neonatal Mice

Journal Reference:
Xinxin Ge, Kathy Zhang, Alexandra Gribizis, Ali S. Hamodi, Aude Martinez Sabino, Michael C. Crair. Retinal waves prime visual motion detection by simulating future optic flow. Science, 2021; 373 (6553): eabd0830 DOI: 10.1126/science.abd0830

Yale University. "Eyes wide shut: How newborn mammals dream the world they're entering." ScienceDaily. ScienceDaily, 22 July 2021. <www.sciencedaily.com/releases/2021/07/210722142037.htm>.

Making clean hydrogen is hard, but researchers just solved a major hurdle

Date:

July 19, 2021

Source:

University of Texas at Austin

Summary:

Researchers have found a low-cost way to solve one half of the water-splitting equation to produce hydrogen as clean energy -- using sunlight to efficiently split off oxygen molecules from water. The finding represents a step forward toward greater adoption of hydrogen as a key part of our energy infrastructure.

Hydrogen, from periodic table of the elements (stock image).
Credit: © remotevfx / stock.adobe.com

For decades, researchers around the world have searched for ways to use solar power to generate the key reaction for producing hydrogen as a clean energy source -- splitting water molecules to form hydrogen and oxygen. However, such efforts have mostly failed because doing it well was too costly, and trying to do it at a low cost led to poor performance.

Now, researchers from The University of Texas at Austin have found a low-cost way to solve one half of the equation, using sunlight to efficiently split off oxygen molecules from water. The finding, published recently in Nature Communications, represents a step forward toward greater adoption of hydrogen as a key part of our energy infrastructure.

As early as the 1970s, researchers were investigating the possibility of using solar energy to generate hydrogen. But the inability to find materials with the combination of properties needed for a device that can perform the key chemical reactions efficiently has kept it from becoming a mainstream method.

"You need materials that are good at absorbing sunlight and, at the same time, don't degrade while the water-splitting reactions take place," said Edward Yu, a professor in the Cockrell School's Department of Electrical and Computer Engineering. "It turns out materials that are good at absorbing sunlight tend to be unstable under the conditions required for the water-splitting reaction, while the materials that are stable tend to be poor absorbers of sunlight. These conflicting requirements drive you toward a seemingly inevitable tradeoff, but by combining multiple materials -- one that efficiently absorbs sunlight, such as silicon, and another that provides good stability, such as silicon dioxide -- into a single device, this conflict can be resolved."

However, this creates another challenge -- the electrons and holes created by absorption of sunlight in silicon must be able to move easily across the silicon dioxide layer. This usually requires the silicon dioxide layer to be no more than a few nanometers, which reduces its effectiveness in protecting the silicon absorber from degradation.

The key to this breakthrough came through a method of creating electrically conductive paths through a thick silicon dioxide layer that can be performed at low cost and scaled to high manufacturing volumes. To get there, Yu and his team used a technique first deployed in the manufacturing of semiconductor electronic chips. By coating the silicon dioxide layer with a thin film of aluminum and then heating the entire structure, arrays of nanoscale "spikes" of aluminum that completely bridge the silicon dioxide layer are formed. These can then easily be replaced by nickel or other materials that help catalyze the water-splitting reactions.

When illuminated by sunlight, the devices can efficiently oxidize water to form oxygen molecules while also generating hydrogen at a separate electrode and exhibit outstanding stability under extended operation. Because the techniques employed to create these devices are commonly used in manufacturing of semiconductor electronics, they should be easy to scale for mass production.

The team has filed a provisional patent application to commercialize the technology.

Improving the way hydrogen is generated is key to its emergence as a viable fuel source. Most hydrogen production today occurs through heating steam and methane, but that relies heavily on fossil fuels and produces carbon emissions.

There is a push toward "green hydrogen" which uses more environmentally friendly methods to generate hydrogen. And simplifying the water-splitting reaction is a key part of that effort.

Hydrogen has potential to become an important renewable resource with some unique qualities. It already has a major role in significant industrial processes, and it is starting to show up in the automotive industry. Fuel cell batteries look promising in long-haul trucking, and hydrogen technology could be a boon to energy storage, with the ability to store excess wind and solar energy produced when conditions are ripe for them.

Going forward, the team will work to improve the efficiency of the oxygen portion of water-splitting by increasing the reaction rate. The researchers' next major challenge is then to move on to the other half of the equation.

"We were able to address the oxygen side of the reaction first, which is the more challenging part, " Yu said, "but you need to perform both the hydrogen and oxygen evolution reactions to completely split the water molecules, so that's why our next step is to look at applying these ideas to make devices for the hydrogen portion of the reaction."

This research was funded by the U.S. National Science Foundation through the Directorate for Engineering and the Materials Research Science and Engineering Centers (MRSEC) program. Yu worked on the project with UT Austin students Soonil Lee and Alex De Palma, along with Li Ji, a professor at Fudan University in China.



Story Source:

Materials provided by University of Texas at Austin. Note: Content may be edited for style and length.


Journal Reference:
Soonil Lee, Li Ji, Alex C. De Palma, Edward T. Yu. Scalable, highly stable Si-based metal-insulator-semiconductor photoanodes for water oxidation fabricated using thin-film reactions and electrodeposition. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-24229-y

University of Texas at Austin. "Making clean hydrogen is hard, but researchers just solved a major hurdle." ScienceDaily. ScienceDaily, 19 July 2021. <www.sciencedaily.com/releases/2021/07/210719143405.htm>.

Workers return to Bangladesh’s garment factories despite record Covid deaths

Hundreds of thousands flock to cities as government allows manufacturers to reopen, with exporters citing fears Western brands would divert orders

Thousands of people return to Dhaka using the Shimulia waterway in Bangladesh. Photograph: Md Manik/SOPA Images/REX/Shutterstock

Global development is supported by


Agence France-Presse
Wed 4 Aug 2021

Hundreds of thousands of Bangladeshi garment workers have returned to major cities, besieging train and bus stations after the government said export factories could reopen despite the deadly coronavirus wave.

Authorities had ordered factories, offices, transport and shops to close from 23 July to 5 August and confined people to their homes for a week, as coronavirus infections and deaths hit record levels.

Larger factories that supply top brands in Europe and North America had been excluded from the nationwide lockdown order.

On Sunday the government gave the go ahead for the country’s 4,500 garment factories, which employ more than four million people, to reopen, sparking a rush back to industrial cities this week.

Influential garment factory owners had warned of “catastrophic” consequences if orders for foreign brands were not completed on time.

Hundreds of thousands who had gone back to their villages to celebrate the Eid al-Adha festival and sit out the lockdown headed to Dhaka by train, bus and ferry. Others travelled on foot in the monsoon rain.

At the Shimulia ferry station, 45 miles south of Dhaka, tens of thousands of workers waited hours for boats to take them to the capital.


Top fashion brands face legal challenge over garment workers’ rights in Asia

Garment factory worker Mohammad Masum, 25, said he left his village before dawn, walked more than 20 miles and took rickshaws to get to the ferry port.

“Police stopped us at many checkpoints and the ferry was packed,” he said.

“It was a mad rush to get home when the lockdown was imposed and now we are in trouble again getting back to work,” said Jubayer Ahmad, another worker.

Bangladesh is one of the world’s largest garment exporters and the industry has become the foundation of the economy for the country of 166 million people.

Mohammad Hatem, vice-president of the Bangladesh Knitwear Manufacturers and Exporters Association, said up to $3bn (£2.1bn) worth of export orders were at risk if factories had stayed closed.

“The brands would have diverted their orders to other countries,” said Hatem.

Labor Union Coalition Urges FTC to Reject Amazon’s $8.5 Billion MGM Deal


By Todd Spangler
Aug 11, 2021 

Courtesy of MGM

A group of four major labor unions representing almost 4 million workers is urging the Federal Trade Commission to block Amazon’s proposed acquisition of MGM.

In a 12-page letter sent Wednesday to the FTC, the unions’ Strategic Organizing Center (SOC) argued Amazon’s $8.45 billion takeover of MGM should be blocked to prevent Amazon from amassing more power in the entertainment industry and exploiting that through anticompetitive business practices.

“Amazon’s proposed acquisition of MGM would further bolster Amazon’s ability to leverage power across multiple lines of business related to the SVOD market and create further harmful vertical integration in the film industry at large,” SOC executive director Michael Zucker wrote in the letter.

The SOC represents four affiliated unions: the Service Employees International Union (SEIU), the International Brotherhood of Teamsters, the Communications Workers of America (CWA) and the United Farmworkers.

The labor coalition alleges that Amazon currently engages in anticompetitive practices in subscription VOD and related markets — for example, by using its dominance in ecommerce to build SVOD market share and by bundling Prime Video with the Prime program to offer the service “at below market prices.”

A copy of the letter is available at this link. It was addressed to FTC Competition Bureau acting director Holly Vedova.

Reps for Amazon and the FTC declined to comment.

The FTC is heading up the antitrust review of Amazon’s deal to acquire MGM, and it is also conducting a broader antitrust probe into Amazon’s business practices. Amazon has formally requested that FTC chair Lina Khan, an outspoken critic of Amazon and other tech giants, recuse herself from antitrust reviews involving the company.

In May, Amazon announced a definitive agreement to acquire MGM and its library of 4,000 movies and 17,000 TV shows, including the storied James Bond film franchise. “We’re looking forward to reimagining and developing the deep catalog of MGM,” Amazon founder Jeff Bezos said at the company’s May 26 annual shareholders meeting.

In the letter, the SOC union coalition argues that Amazon has a well-documented history of leveraging its dominance in ecommerce to gain share in vertically adjacent markets using a range of unfair and anticompetitive practices.

Allowing Amazon to acquire MGM would give Amazon expanded power to “impose onerous contract terms such as all-rights provisions, which sap income from other distribution methods and can also curb the benefits of community engagement with content by, for example, restricting its availability in educational settings,” SOC’s Zucker wrote in the letter. And it would give the company even more creative control over content, presenting “troubling implications” for “the integrity and diversity of content available to consumers and, by extension, freedom of expression itself,” the SOC argues in its letter.”

The SOC said the FTC should place significant conditions on the merger, if it does allow it to proceed — but that the “best course would be to prevent Amazon from gaining an additional foothold in the SVOD market from which to expand its power and reach into this important area of economic and cultural significance for our country,” Zucker’s letter concluded.






According to Amazon, by buying MGM, it will be able to offer more choice and more content for consumers in the highly competitive entertainment and streaming-video markets. Amazon hasn’t said when it expects the MGM deal to close. The proposed acquisition is far smaller than Disney’s takeover of 20th Century Fox or AT&T’s deal for WarnerMedia (which is now being unwound).

NEVER BUY USED, NO WARRANTY

Cost of used icebreakers Ottawa is buying from Quebec shipyard approaches 

$1-billion

LEE BERTHIAUME
OTTAWA
THE CANADIAN PRESS
AUGUST 11, 2021

The federal government has quietly shelled out more than $900 million to Quebec shipyard Chantier Davie for three second-hand icebreakers originally billed as costing only $600 million when the deal was announced three years ago. JACQUES BOISSINOT/THE CANADIAN PRESS

The cost of three second-hand icebreakers that the federal Liberal government is buying from Quebec shipyard Chantier Davie is inching closer to the $1-billion mark as Ottawa keeps quietly adding money to the controversial deal.

The most recent cash infusion came last week as the government handed Davie another $68.9-million to continue converting and upgrading the icebreakers, bringing the total cost for the three vessels to more than $912-million.

That represents a significant increase over the original $610-million price tag announced by the Liberals when they agreed to purchase the three Norwegian-built civilian icebreakers for the Canadian Coast Guard in August 2018.

Both Davie as well as the Fisheries Department defended the added costs and the overall deal in separate statements, saying the agreement will deliver much-needed vessels for the coast guard to use until brand-new replacements can be built.

The Quebec shipyard and Ottawa are currently negotiating a deal for Davie to build six new medium icebreakers in the coming years as part of the federal government’s multibillion-dollar shipbuilding procurement strategy.

Davie spokesman Mathieu Filion says the shipyard has delivered two of the interim icebreakers while the third is undergoing conversion work. The Fisheries Department says it won’t be delivered until next summer – four years after the deal was signed.

The icebreakers “are already filling a major strategic gap in Canada’s icebreaking capability when it is most needed,” Filion said in a statement. “The unacceptable alternative was to wait several years for a new fleet to be delivered.”

He added that any cost increases were agreed to “in full transparency” with the government.

“Before entering the coast guard fleet, the ships required refit and conversion work at Chantier Davie Canada Inc. to ensure they met Canadian regulatory standards and operational requirements,” Fisheries Department spokesperson Robin Jahn said in an email.

“The refit and conversion work on the medium interim icebreakers will allow the coast guard to continue delivering its services during vessel life extension and repair periods for existing vessels while new ships are being built, ensuring operational requirements are met.”

One expert says the added costs shouldn’t come as a surprise given what he sees as the political nature of the deal. Prime Minister Justin Trudeau announced negotiations for the deal during a radio interview in Quebec City in early 2018.

“It was a vote-getting mechanism,” said University of Calgary professor Rob Huebert, one of Canada’s foremost experts on the Arctic and Canadian Coast Guard. “Because at the end of the day, we’re going to spend just as much on these second-hand vessels (as new ones).”

Trudeau’s announcement did coincide with concerns about a shortage of icebreakers given the age of the coast guard’s existing fleet and the fact the government has yet to complete a plan for when and how it will replace them.

But it also followed an intense lobbying campaign by Davie, the Quebec government and federal opposition parties for Ottawa to give the shipyard work, and Trudeau’s on-air announcement surprised many – including the company and coast guard officials.

A senior coast guard official later told The Canadian Press in an interview that the three “interim” vessels, which were purchased without a competition, would be used for the next 15 to 20 years.

Huebert suggested the deal represented the latest in a trend of federal politics playing a role when it comes to the purchase of new ships for the Royal Canadian Navy and coast guard, with the latter repeatedly having those kinds of calculations superseding operational necessity.


That includes the Liberal government’s decision to order two naval Arctic patrol ships from Halifax-based Irving Shipyards for the coast guard, even though the agency responsible for managing Canada’s waterways didn’t want them.

Huebert also cited the Liberals’ recent decision to have Davie and Vancouver-based Seaspan each build a new polar icebreaker in the coming years, a move that will improve both shipyards despite the added costs of farming such work to two yards instead of one.

“So you put the entire picture together, and you have one in which the decisions are being made to create the coast guard fleet that are really being built on what is best for the Liberal party, not what is best for Canada,” he said.

“And the fact that these are just going to cost more and more – I think most people knew that was going to be happening – illustrates this whole point.”

Kenney’s ‘maverick’ pandemic stance puts him at odds with most Albertans

GS

By Gillian StewardContributing Columnist

Mon., Aug. 9, 2021timer3 min. read

Some Albertans love to think of themselves as “mavericks.”

Perhaps that’s why, when compared to other provinces, so many people here refuse to get vaccinated — they don’t like other people telling them what to do even when it might be good for them and everyone else.

And clearly, throughout the pandemic Premier Jason Kenney has positioned himself as the heroic maverick who is sure he can beat the coronavirus by blazing his own trail. No sissy stuff for him. He’d rather live it up at the Calgary Stampede, no matter the consequences.

Kenney is so sure he has vanquished the virus that by the middle of August he says we won’t even need readily available testing or contact tracing. Heck, if anyone is actually infected they can simply go wherever they want — school, live concerts, grocery stores — because by then everyone should be tough enough to just deal with it.

That’s the plan outlined last week by Deena Hinshaw, the chief medical officer of health, and staunchly defended by Kenney, even though Alberta now has the highest rate of active COVID-19 cases in the country — four times the Ontario rate.

But according to Kenney, anyone who suggests this plan is putting people, especially unvaccinated kids, in harm’s way is simply “fear mongering.” What else would a maverick-kind-of-guy say?

The original “mavericks” were actually unbranded calves that wandered about blazing their own trails. They were named after Samuel Maverick, a 19th century Texas lawyer, slave holder, and owner of vast rangelands, who acquired 400 cattle as settlement of a debt but was too busy to organize a branding crew.

In 2001, “Mavericks: An Incorrigible History of Alberta” by Calgary author Aritha van Herk was published and many Albertans revelled in the notion of themselves as “people who step out of bounds, refuse to do what we are told, take risks and then laugh when we fall down and hit the ground.”

Van Herk also wrote that since the original maverick calves could be poached by cowboys or butchered for their meat, mavericks, just like Albertans, “were resistant to being caught, owned, herded, taxed or identified.”

Since she wrote the book on mavericks, I asked her if she attributed the recalcitrance of the unvaccinated and Kenney’s stance on the pandemic to Albertans’ “maverick” nature.

She definitely does not.

“My definition of mavericks has nothing to do with this vaccine-resistant, separatist-directed, grievance mongering attitude currently exerting itself. It was about the wish to help others and to get ahead, and the retrograde behaviour now relates to that not at all,” she replied via email.

“Masking and vaccination and science-informed decisions have been politicized by the right to an extent that people now believe they are exercising a political choice when they decline or refuse or demonstrate skepticism about health and vaccination. It is a sign of the extent to which Trumpian politics have infiltrated Alberta. I am, to be honest, disgusted.”

If, as van Herk says, real mavericks aren’t simply recalcitrant loners but people who take risks to help others, then the title is more apt for all the physicians, nurses, epidemiologists, teachers, parents, and students who have spoken out or joined public demonstrations demanding that the government continue testing, contact tracing and isolation of infected individuals.

Professional organizations including the Alberta Medical Association, the Alberta College of Family Physicians and the Canadian pediatric Society have added their voices.

They are not asking for lockdowns or tighter restrictions. They simply want the government to keep close track of COVID-19 and share the information so everyone can do what they need to do to protect themselves.

Given all the resistance from both inside and outside Alberta and the rising number of COVID-19 cases, Kenney may have to back track. He’s certainly done that before when rapidly rising cases, hospitalizations and deaths confirmed that his approach wasn’t working.

Or he just might double down, determined to prove that lifting all restrictions on July 1 and then encouraging everyone to party it up at the Calgary Stampede cast him as a trail blazer, a real maverick.

Trouble is, given Kenney’s plummeting popularity most Albertans don’t see him that way. The sooner he realizes that the better for everyone.

GS

Gillian Steward is a Calgary-based writer and freelance contributing columnist for the Star. Follow her on Twitter: @GillianSteward

COVID-19: Alberta advocates take fight for health measures in schools to federal government

By Heide Pearson Global News
Posted August 10, 2021 

A group including several Alberta health experts is bypassing the province and directly asking the prime minister for funding to make schools safer amid the ongoing COVID-19 pandemic. Lauren Pullen reports.

Alberta advocates fighting for stronger public health measures as children return to school amid what officials call a fourth wave of COVID-19 infections are taking their battle to the federal government.

In a letter addressed to Prime Minister Justin Trudeau and posted to Twitter on Tuesday, 24 voices called upon the federal government to step in where they claim the Alberta government is failing.

READ MORE: As Alberta schools wait for provincial COVID-19 guidance, some keep previous measures in place

“Despite clear evidence showing that ventilation, filtration, masks and other basic health measures can reduce transmission of (COVID-19) when used together, the Alberta government is unwilling to spend the money required to enact such measures,” the letter states.

The government has yet to announce what, if any, public health measures will be implemented in Alberta classrooms this fall, however, in July, Premier Jason Kenney assured parents students would be heading back in-person, and to “near-normal learning.”

Risks for children posed by COVID-19 are extremely low’: Kenney on children returning to school after removing health measures – Aug 3, 2021

Late last month, the UCP announced it was eliminating more public health measures over the coming weeks, including asymptomatic testing, contact tracing and the requirement that anyone who tests positive for COVID-19 to isolate.

Doctors, advocates, parents and other officials have expressed their concern over Alberta’s approach to easing restrictions, however, Kenney and Health Minister Tyler Shandro have defended the government’s decision making and chief medical officer of health Dr. Deena Hinshaw’s advice.


READ MORE: ‘This is a travesty’: Albertans protest COVID-19 rule rollback for second day

Now, a coalition of those voices is asking the federal government to step in and give Alberta school boards $80 million to ensure proper ventilation in classrooms, air quality testing and masks are in place before the school year begins.

“Given the track record of the Alberta government in failing to pass along federal funding, leaving hundreds of millions of dollars on the table, we implore the federal government to directly fund Alberta school boards to help make classrooms safer,” the letter reads

The coalition, made up of doctors, union representatives, parent advocates and academics, says providing HEPA filters for K-6 classrooms — where children aren’t of age to be vaccinated — would cost approximately $65 million, providing masks for students in grades K-6 will cost $9.6 million and providing CO2 monitors for every classroom for real-time air quality testing would cost $6 million.

Alberta parents concerned as province lifts COVID-19 protocols weeks before school resumesAlberta parents concerned as province lifts COVID-19 protocols weeks before school resumes – Jul 29, 2021

“Schools, already grappling with significant funding shortages and over-full classrooms where physical distancing is not possible, are unable to pay for the necessary upgrades,” the letter said.
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The group went on to point out that “almost every expert in the country” has raised questions about Alberta’s plan forward, particularly as cases of the Delta variant of COVID-19 continue to rise across the globe.

“Our children will pay the price for this enormous gamble, and while they may not overwhelm the health-care system, they will face the consequences of increasing hospitalizations as well as the unknown long-term repercussions when COVID-19 runs rampant through an unvaccinated population.”


READ MORE: Alberta plan to remove COVID-19 measures is ‘risky gamble,’ fed health minister tells Shandro

On Monday, Kenney said the education and health ministries are working on the “critically important” plan for a safe return to school.

“Vaccines are not available to children under the age of the 12, but we also know that COVID-19 does not represent a greater threat for severe outcomes to younger children than the regular seasonal flu,” he said.

“I know that Dr. Hinshaw and her team are understandably concerned of a resurgence of more conventional respiratory virus and diseases this autumn, including various kinds of flus and colds, and want to have the resources to address all of those challenges safely within the school system.”

Jason Kenney responds to criticism over lifting more COVID-19 rules – Aug 3, 2021

In an emailed statement, Ministry of Education spokesperson Nicole Sparrow said “we are confident that all school authorities have been provided the supports they need to provide a safe, world-class education to their students.

“We know that many parents and teachers have questions and an additional guidance document is being finalized and will be released in mid-August to support return to school. Alberta’s government will continue to follow the expert advice of Alberta’s chief medical officer of health,” she said.

Sparrow outlined that through the course of the pandemic, the government made $1 billion available to Alberta school boards, including a $120-million operating fund boost, $10 million for PPE and $262 million which came from the federal government. She added the government also gave schools $250 million in maintenance spending for mechanical upgrades, of which $44 million was used for HVAC and ventilation.

READ MORE: Alberta announces new funding for school maintenance, no word yet on fall return

“While the letter falsely claims that Alberta’s government withheld federal supports for school divisions during the pandemic, every dollar of funding received through the Safe Return to Class Fund was immediately allocated to school authorities once it was is received from the federal government,” Sparrow said.

When asked if directly giving Alberta school boards money was something the federal government would consider, press secretary for the federal Department of Intergovernmental Affairs Jean-Sebastien Comeau said the Liberals have already given money to provinces and territories to help with the costs of keeping classrooms safe.

“The (Safe Return to Class) Fund helped provinces and territories work alongside school boards to meet the needs of their students and staff by providing funds to support adapted learning spaces, improved air ventilation, increased hand sanitation and hygiene and purchases of personal protective equipment and cleaning supplies,” Comeau said.

“Provinces and territories had the flexibility to spend funding according to their priorities.”

Physicists Detect Strongest Evidence Yet of Matter Generated by Collisions of Light


(sakkmesterke/iStock/Getty Images Plus)

MICHELLE STARR
10 AUGUST 2021

According to theory, if you smash two photons together hard enough, you can generate matter: an electron-positron pair, the conversion of light to mass as per Einstein's theory of special relativity.

It's called the Breit-Wheeler process, first laid out by Gregory Breit and John A. Wheeler in 1934, and we have very good reason to believe it would work.

But direct observation of the pure phenomenon involving just two photons has remained elusive, mainly because the photons need to be extremely energetic (i.e. gamma rays) and we don't have the technology yet to build a gamma-ray laser.

Now, physicists at Brookhaven National Laboratory say they've found a way around this stumbling block using the facility's Relativistic Heavy Ion Collider (RHIC) - resulting in a direct observation of the Breit-Wheeler process in action.

"In their paper, Breit and Wheeler already realized this is almost impossible to do," said physicist Zhangbu Xu of Brookhaven Lab.

"Lasers didn't even exist yet! But Breit and Wheeler proposed an alternative: accelerating heavy ions. And their alternative is exactly what we are doing at RHIC."

But what do accelerated ions have to do with photon collisions? Well, we can explain.

The process involves, as the collider's name suggests, accelerating ions - atomic nuclei stripped of their electrons. Because electrons have a negative charge and protons (within the nucleus) have a positive one, stripping it leaves the nucleus with a positive charge. The heavier the element, the more protons it has, and the stronger the positive charge of the resulting ion.

The team used gold ions, which contain 79 protons, and a powerful charge. When gold ions are accelerated to very high speeds, they generate a circular magnetic field that can be as powerful as the perpendicular electric field in the collider. Where they intersect, these equal fields can produce electromagnetic particles, or photons.

"So, when the ions are moving close to the speed of light, there are a bunch of photons surrounding the gold nucleus, traveling with it like a cloud," Xu explained.

At the RHIC, ions are accelerated to relativistic speeds - those that are a significant percentage of the speed of light. In this experiment, the gold ions were accelerated to 99.995 percent of light speed.

This is where the magic happens: When two ions just miss each other, their two clouds of photons can interact, and collide. The collisions themselves can't be detected, but the electron-positron pairs that result can.

However, it's not enough to just detect an electron-positron pair, either.

Diagram showing how the near-miss of gold ions produces photon collisions. (Brookhaven Lab)

That's because the photons produced by the electromagnetic interaction are virtual photons, popping briefly in and out of existence, and without the same mass as their 'real' counterparts.

To be a true Breit-Wheeler process, two real photons need to collide - not two virtual photons, nor a virtual and a real photon.


At the ions' relativistic speeds, the virtual particles can behave like real photons. Thankfully, there's a way physicists can tell which electron-positron pairs are generated by the Breit-Wheeler process: the angles between the electron and the positron in the pair generated by the collision.

Each type of collision - virtual-virtual, virtual-real and real-real - can be identified based on the angle between the two particles produced. So the researchers detected and analyzed the angles of over 6,000 electron-positron pairs generated during their experiment.

They found that the angles were consistent with collisions between real photons - the Breit-Wheeler process in action.

"We also measured all the energy, mass distributions, and quantum numbers of the systems. They are consistent with theory calculations for what would happen with real photons," said physicist Daniel Brandenburg of Brookhaven Lab.

"Our results provide clear evidence of direct, one-step creation of matter-antimatter pairs from collisions of light as originally predicted by Breit and Wheeler."

The argument could be very reasonably made that we won't have a direct first detection of the pure, single photon-photon Breit-Wheeler process until we collide photons approaching the energy of gamma rays.

Nevertheless, the team's work is highly compelling stuff - at the very least, it shows that we are barking up the right tree with Breit and Wheeler.

We'll be continuing to watch this space, avidly.

The research has been published in Physical Review Letters.

Scientists detect characteristics of the birth of a major challenge to harvesting fusion energy on Earth

Date:August 10, 2021

Source:DOE/Princeton Plasma Physics Laboratory

Summary:Novel camera detects the birth of high-energy runaway electrons, which may lead to determining how to prevent damage caused by the highly energetic particles.


A key challenge for scientists striving to produce on Earth the fusion energy that powers the sun and stars is preventing what are called runaway electrons, particles unleashed in disrupted fusion experiments that can bore holes in tokamaks, the doughnut-shaped machines that house the experiments. Scientists led by researchers at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) have used a novel diagnostic with wide-ranging capabilities to detect the birth, and the linear and exponential growth phases of high-energy runaway electrons, which may allow researchers to determine how to prevent the electrons' damage.

Initial energy

"We need to see these electrons at their initial energy rather than when they are fully grown and moving at near the speed of light," said PPPL physicist Luis Delgado-Aparicio, who led the experiment that detected the early runaways on the Madison Symmetric Torus (MST) at the University of Wisconsin-Madison. "The next step is to optimize ways to stop them before the runaway electron population can grow into an avalanche," said Delgado-Aparicio, lead author of a first paper that details the findings in the Review of Scientific Instruments.

Fusion reactions produce vast amounts of energy by combining light elements in the form of plasma -- the hot, charged state of matter composed of free electrons and atomic nuclei that makes up 99 percent of the visible universe. Scientists the world over are seeking to produce and control fusion on Earth for a virtually inexhaustible supply of safe and clean power for generating electricity.

PPPL collaborated with the University of Wisconsin to install the multi-energy pinhole camera on MST, which served as a testbed for the camera's capabilities. The diagnostic upgrades and redesigns a camera that PPPL had previously installed on the now-shuttered Alcator C-Mod tokamak at the Massachusetts Institute of Technology (MIT), and is unique in its ability to record not only the properties of the plasma in time and space but its energy distribution as well.

That prowess enables researchers to characterize both the evolution of the superhot plasma as well as the birth of runaway electrons, which begin at low energy. "If we understand the energy content I can tell you what is the density and temperature of the background plasma as well as the amount of runaway electrons," Delgado Aparicio said. "So by adding this new energy variable we can find out several quantities of the plasma and use it as a diagnostic."

Novel camera

Use of the novel camera moves technology forward. "This certainly has been a great scientific collaboration," said physicist Carey Forest, a University of Wisconsin professor who oversees the MST, which he describes as "a very robust machine that can produce runaway electrons that don't endanger its operation."

As a result, Forest said, "Luis's ability to diagnose not only the birth location and initial linear growth phase of the electrons as they are accelerated, and then to follow how they are transported from the outside in, is fascinating. Comparing his diagnosis to modeling will be the next step and of course a better understanding may lead to new mitigation techniques in the future."

Delgado-Aparicio is already looking ahead. "I want to take all the expertise that we have developed on MST and apply it to a large tokamak," he said. Two post-doctoral researchers who Delgado-Aparicio oversees can build upon the MST findings but at WEST, the Tungsten (W) Environment in Steady-state Tokamak operated by the French Alternative Energies and Atomic Energy Commission (CEA) in Cadarache, France.

"What I want to do with my post-docs is to use cameras for a lot of different things including particle transport, confinement, radio-frequency heating and also this new twist, the diagnosis and study of runaway electrons," Delgado-Aparicio said. "We basically would like to figure out how to give the electrons a soft landing, and that could be a very safe way to deal with them."


Story Source:

Materials provided by DOE/Princeton Plasma Physics Laboratory. Original written by John Greenwald. Note: Content may be edited for style and length.


Journal Reference:
L. F. Delgado-Aparicio, P. VanMeter, T. Barbui, O. Chellai, J. Wallace, H. Yamazaki, S. Kojima, A. F. Almagari, N. C. Hurst, B. E. Chapman, K. J. McCollam, D. J. Den Hartog, J. S. Sarff, L. M. Reusch, N. Pablant, K. Hill, M. Bitter, M. Ono, B. Stratton, Y. Takase, B. Luethi, M. Rissi, T. Donath, P. Hofer, N. Pilet. Multi-energy reconstructions, central electron temperature measurements, and early detection of the birth and growth of runaway electrons using a versatile soft x-ray pinhole camera at MST. Review of Scientific Instruments, 2021; 92 (7): 073502 DOI: 10.1063/5.0043672


Cite This Page:
DOE/Princeton Plasma Physics Laboratory. "Scientists detect characteristics of the birth of a major challenge to harvesting fusion energy on Earth." ScienceDaily. ScienceDaily, 10 August 2021. <www.sciencedaily.com/releases/2021/08/210810161346.htm>.

 

New study analyzes role of scent compounds in the co-evolution of bats and pepper plants

by Burke Museum

An infographic summarizing the results of the study, including how the scent preferences of short-tailed fruit bats relate to scent chemical evolution. Credit: Burke Museum

A new study in the journal Proceedings of the Royal Society B by researchers at the University of Washington (UW), Burke Museum, and Stony Brook University, finds important clues on how bats and Piper (pepper) plants in Central America have co-evolved to help each other survive.

Specifically, the team studied the complex mixture of Volatile Organic Compounds (VOCs) that Piper fruits produce when they are at prime ripeness, and how these VOCs may have evolved to attract scent-oriented short-tailed fruit bats (the Carollia genus) who then eat the fruits and excrete the seeds into the landscape. Plant-animal interactions have captured the attention of biologists for centuries, and are key to maintaining the biodiversity of tropical ecosystems. The dispersal syndrome hypothesis—an explanation of how mutually-beneficial relationships between plants and frugivores may lead to co-evolution—proposes that when animals are effective seed dispersers, they may select for fruit traits (e.g., size, color, odor) that match their sensory abilities (e.g., vision, olfaction), and vice versa. However, few studies have tested this hypothesis for complex traits like fruit scents. This study provides one of the first tests of bat-driven, fruit scent evolution.

The study is based on data collected during fieldwork at La Selva Biological Station, Costa Rica. There, Piper is highly diverse with over 50 recognized species. It is also a location where three Carollia species (C. castanea, C. sowellii, and C. perspicillata) are some of the most abundant bats year-round and coexist with approximately 62 other bat species.

The team spent hundreds of hours searching and collecting ripe fruits from Piper to extract and quantify the VOCs that make up their fragrant scent. Concurrently, they collected fecal samples from live bats and then released them back into the wild to determine which Piper species the bats were eating and how much. The researchers also conducted behavioral experiments with wild bats where they offered options of unripe fruits enhanced with the most-common VOCs found in local Piper plants. Video cameras and microphones recorded the bats' feeding behaviors and echolocation calls.

The team found Piper fruit scent bouquets were complex and diverse. They identified and quantified 249 VOCs in ripe fruit scents across 22 Piper species. Some compounds were found in the fruit scent of most species—like alpha-caryophyllene, which has a spicy scent like cinnamon or cloves. Others, like 2-heptanol, were only found in a few Piper species. The diet studies showed that, while the three Carollia species varied in their reliance on Piper as a food source, all consumed a lot of a few Piper species, and a little of many others. Surprisingly, this was not related to how abundant the Piper species are at La Selva, so the bats must choose Piper fruits based on other characteristics and not just how well represented they are across the landscape. The team's behavioral experiments provided some clues to what might be happening: Bats preferred samples spiked with 2-heptanol, a VOC found in the fruit scents of the Piper species they eat the most.

"These findings suggest bats use specific chemicals in the fruit scent bouquet not only to select ripe fruits, but to find the specific Piper species that make up the bulk of their diet." Dr. Sharlene Santana, UW Biology department professor and Burke Museum mammal curator said. "By helping them communicate with the bats, these chemical signals are likely a component of a dispersal syndrome in these plants."

Through advanced statistical and evolutionary analyses of the fruit scent chemistry and bat diet data, the team further demonstrated that the evolutionary patterns of chemical diversity and the presence of specific compounds in Piper fruit scents is associated with greater bat consumption and scent preferences. This highlights the potential effect of bat frugivory on the evolution of fruit chemistry, a relationship that contributes to the extreme diversity of tropical fruiting plants worldwide.

"Flying in the dark means bats cannot find ripe fruit by sight, but rely on olfaction instead," said Dr. Liliana Dávalos, Stony Brook Ecology and Evolution department professor. "Olfaction is the bridge between the plant signal and bat fruit consumption, and finding the specific VOCs bats respond to opens the door to matching olfactory receptor genes to important VOCs, which has been impossible until now."

A short-tailed fruit bat, Carollia castanea, a Piper specialist. Credit: David Villalobos Chaves

Understanding the relationship between bats and pepper plants not only contributes to knowledge about co-evolution of these species, but also has benefits for rainforest habitat conservation. Piper are some of the first plants to grow in forest gaps and edges, and Carollia—as key dispersers of Piper seeds—can help restore plant life in logged areas.

"Our current and future work is identifying the odorant receptors that allow the bats to detect the fruit scents. This will allow us to link the ecology and evolution of these relationships with the physiological mechanisms," said Jeffrey Riffell, UW Biology department professor.

How chemical diversity in plants facilitates plant-animal interactions

More information: Sharlene E. Santana et al, Fruit odorants mediate co-specialization in a multispecies plant–animal mutualism, Proceedings of the Royal Society B: Biological Sciences (2021). DOI: 10.1098/rspb.2021.0312

Journal information: Proceedings of the Royal Society B 

Provided by Burke Museum

Science of smell: The first molecular images of odor receptors at work
By Michael Irving
August 11, 2021

A new study examines how olfactory receptors respond to odor molecules
Yaruta/Depositphotos

Our sense of smell seems to be the most complicated, and as such it’s the least understood. To help shed some light on the system, researchers at Rockefeller University have taken the first cryo-electron microscope images of an olfactory receptor at work in the simple system of an insect.

Receptors are key structures that help us understand the world around us through our five senses. There are touch receptors in the skin, photoreceptors in the retina, taste receptors on the tongue, sound-sensitive receptors in the inner ear, and olfactory receptors in the nose. They all respond to different stimuli, opening ion channels to transmit signals to the brain to interpret what we’re experiencing.

But the olfactory receptors are the most mysterious of all. While we only need three types in the eyes to see and six in the ear to hear, it takes over 400 receptors to smell – and even these pull double duty to detect the millions of different odorant molecules. A specific smell like coffee or roses is made up of hundreds of chemical components that stimulate different arrangements of receptors, and this precise activation pattern helps the brain decode what exactly it’s smelling.

An illustration of an olfactory receptor in its unexcited state (blue) and when it's been activated (pink) by an odor molecule. When activated, an ion channel in the center dilates, sending a message to the brain that the receptor has been activated.
The Rockefeller University

“The olfactory system has to recognize a vast number of molecules with only a few hundred odor receptors or even less,” says Vanessa Ruta, corresponding author of the study. “It’s clear that it had to evolve a different kind of logic than other sensory systems.”

So for the new study, the team set out to study that complex logic. The main question they wanted to answer was how a single receptor is able to recognize different chemicals, despite those molecules having different sizes and shapes.

To find out, they used a technique called cryo-electron microscopy, which involves firing a beam of electrons at a frozen sample to produce a 3D image of its tiny molecular structures. This was performed on the olfactory receptors of an insect called a jumping bristletail, which has a relatively simple odor-sensing system containing only five types of receptors.


Of these, the team chose one called OR5, which responded to 60 percent of the odor molecules they tested it on. Then they studied the structure of the OR5 receptor when it was alone, and when it was bound to one of two odorant molecules – eugenol (or clove oil), and the insect repellent DEET.

“We learned a lot from comparing these three structures,” says Ruta. “One of the beautiful things you can see is that in the unbound structure the pore is closed, but in the structure where it’s bound with either eugenol or DEET, the pore has dilated and provides a pathway for ions to flow.”

Next, the researchers examined where exactly the molecules were binding to the receptor. Despite being very different, the two molecules appeared to be binding at exactly the same location, within one pocket on the receptor. That actually goes against the two leading hypotheses – that receptors bind to a specific part of a molecule that may be common to a large group of odors, or that the receptors use different pockets to hold different molecules. Weirder still, the receptor and molecule pairs were only binding weakly.

“These kinds of nonspecific chemical interactions allow different odorants to be recognized,” says Ruta. “In this way, the receptor is not selective to a specific chemical feature. Rather, it’s recognizing the more general chemical nature of the odorant.”

The team says that this observation helps explain how receptors are able to bind to large swathes of odor molecules, but not all. That helps smaller numbers of receptors build into an olfactory system that can recognize millions of different chemicals.

They also found that it only takes one mutation in the amino acids of the binding site to change which molecules will stick. That in turn can explain how so many varieties of odor receptors have evolved in insects. The general principle behind this likely also occurs in other animals, including humans, the team concludes.


The research was published in the journal Nature.

Source: Rockefeller University