Pac-Man carving by laser cutting. Credit: H. Borchers et al.
A gentler, more precise laser cutting technique
Laser cutting techniques are usually powered by high energy beams, so hot that they melt most materials. Now scientists from McGill University have developed a gentler, more precise technique using low-power visible light.
The new process called ‘cold photo-carving’ uses a fraction of the energy required in traditional laser cutting techniques. “We engineered crystal building blocks that can be cut by low-power light with amazing precision. Unlike traditional heat cutting methods, sculpting down to a resolution of nanometres is possible with our approach because light can be focused more precisely than heat can,” says Professor Tomislav Friščić of the Department of Chemistry.
According to the researchers, the new technique could also be used to engrave complex patterns into surfaces. “Imagine taking the famous geoglyphs in the Nazca Desert in Peru and engraving that pattern at a million-times the reduced size,” say Professor Friščić. The researchers hope that the new approach could one day be developed to create new materials like metals or ceramics that are easily shaped or cut using low-power light and are now looking at potential applications in solar cell materials.
“Cold photo-carving of halogen-bonded co-crystals of a dye and a volatile co-former using visible light” by T. H. Borchers et al. was published in Nature Chemistry.
How COVID-19 put poverty reduction back on the agenda
Lower income people bore the brunt of the economic repercussions of the COVID-19 pandemic. As a result, efforts to reduce poverty were adopted in Canada and the United States. But how did partisan politics shape each government’s response? Exploring the political dynamics at play, a team of researchers including McGill University Professor Daniel Béland, traces the adoption and evolution of anti-poverty measures in both countries.
“The COVID-19 crisis helped trigger a political shift in the U.S. that saw Democrats take the White House and the Senate after many years of Republican control. This made the adoption and implementation of anti-poverty measures possible for the first time in a decade,” says Professor Daniel Béland of the Department of Political Science, who also serves as a Director of the McGill Institute for the Study of Canada. “Since 2011, Republican control of at least one chamber of Congress along with the four years of the Trump presidency prevented the adoption of ambitious policies capable of significantly reducing poverty,” says co-author Philip Rocco of Marquette University.
The United States has a two-party system. Since there isn’t a third social-democratic party, pressures for progressive policies come from social movements and factions within the Democratic Party itself, say the researchers. A crucial factor for the recent adoption of poverty reduction policies is the rise of the progressive wing of the Democratic Party over the last decade and the nomination and the election of more progressive candidates in the Senate.
“This contrasts with Canada, where the existence of the New Democratic Party (NDP) can push the Liberals to adopt more redistributive policies. Especially since the Liberal Party’s electoral strategy has remained unchanged: stealing votes from the social-democratic NDP to beat the Conservatives,” says co-author Shannon Dinan of Université Laval. According to the researchers, this strategy may help explain the anti-poverty leaning of some of the Liberal government’s policies.
“Studying these dynamics can give us a greater understanding of the politics of poverty reduction and help us anticipate what could happen in a future crisis,” says co-author Alex Waddan of University of Leicester.
"COVID-19, poverty reduction, and partisanship in Canada and the United States" by Daniel Béland et al. was published in Policy and Society.
The queen wins over the court jester. Credit: Tadas Razmas
Which rules evolutionary change: life or climate?
The fossil record over the last half a billion years shows biodiversity as a zigzagging pattern of species births and extinctions. For decades scientist have attempted to answer the question: Which rules supreme – life or the environment? To explain this macroevolution, scientists have used two opposing theories: the Red Queen versus the Court Jester theory, inspired by the story Alice in Wonderland. New research by McGill University and Vilnius University puts these two theories to the test.
“According to the Red Queen hypothesis, interactions between species, like competition, are the most important drivers of evolutionary change, whereas the Court Jester hypothesis advances that environmental perturbances, like climate change, are the most important,” says McGill Professor Shaun Lovejoy of the Department of Physics.
Analyzing fluctuations in marine animal biodiversity and climate conditions over last half billion years, the researchers found that at shorter time scales, diversity acts like the Court Jester system (environment is the driver), with fluctuations increasing with passing time, reaching their maximum at 40 million years. Beyond this time scale they followed the equilibrating Red Queen rules (competition and evolutionary innovation are the drivers).
“After 40 million years the diversity of marine animals becomes more and more autonomous from the climate. Therefore, life acquires autonomy at the largest time scales without the need of stabilization of the physical environment,” says Andrej Spiridonov of Vilnius University.
“Life rather than climate influences diversity at scales greater than 40 million years” by Andrej Spiridonov and Shaun Lovejoy was published in Nature.
About McGill University
Founded in Montreal, Quebec, in 1821, McGill University is Canada’s top ranked medical doctoral university. McGill is consistently ranked as one of the top universities, both nationally and internationally. It is a world-renowned institution of higher learning with research activities spanning three campuses, 11 faculties, 13 professional schools, 300 programs of study and over 39,000 students, including more than 10,400 graduate students. McGill attracts students from over 150 countries around the world, its 12,000 international students making up 30% of the student body. Over half of McGill students claim a first language other than English, including approximately 20% of our students who say French is their mother tongue.