Sean Bettam

Geoscientists confirm 'dripping' of Earth’s crust beneath Türkiye's Central Anatolian Plateau

Christopher.Sorensen — Wed, 18 Sep 2024 10:35:54 +0000

Geoscientists confirm 'dripping' of Earth’s crust beneath Türkiye's Central Anatolian Plateau

Christopher.Sorensen Wed, 09/18/2024 - 06:35

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Earth scientists have identified active sinking at the Konya Basin in Türkiye due to the dripping of lithospheric material beneath the planet’s surface over millions of years (photo by temizyurek/Getty Images)

Sean Bettam

Topic

Breaking Research

Earth Sciences

Faculty of Arts & Science

Global

Research & Innovation

Recent satellite data reveal that the Konya Basin in the Central Anatolian Plateau of Türkiye is continually being reshaped over millions of years, according to a new analysis led by Earth scientists at the University of Toronto.

The researchers say experimental simulations – combined with geological, geophysical and geodetic data – explain the enigmatic sinking of the basin within the rising plateau interior and further suggests a new class of plate tectonics that has implications for other planets that do not have Earth-like plates such as Mars and Venus.

The study, published in Nature Communications, shows the sinking in the region is due to multi-stage lithospheric dripping – a phenomenon named for the instability of rocky material that makes up Earth’s crust and upper mantle. As dense rock fragments beneath the surface detach and sink into the more fluid layer of the planet’s mantle, major landforms such as basins and mountainous folding of the crust form at the surface.

“Looking at the satellite data, we observed a circular feature at the Konya Basin where the crust is subsiding or the basin is deepening,” says lead author Julia Andersen, a PhD candidate in ��ֱ��’s department of Earth sciences in the Faculty of Arts & Science.

“This prompted us to look at other geophysical data beneath the surface where we saw a seismic anomaly in the upper mantle and a thickened crust, telling us there is high-density material there and indicating a likely mantle lithospheric drip.”

Artist’s impression of the multi-stage lithospheric dripping process in Central Anatolia (illustration by Nevena Niagolova)

The results echo a similar investigation by the researchers into the formation of the Arizaro Basin in the Andes Mountains of South America, suggesting the phenomenon can occur anywhere on the planet and explains tectonic processes typically found within mountain plateau regions.

Past studies show the Central Anatolian Plateau has risen by as much as one kilometre over the past 10 million years because of the lithospheric dripping phenomenon.

“As the lithosphere thickened and dripped below the region, it formed a basin at the surface that later sprang up when the weight below broke off and sank into the deeper depths of the mantle,” says Russell Pysklywec, a professor in the department of Earth sciences and a co-author of the study.

“We now see the process is not a one-time tectonic event and that the initial drip seems to have spawned subsequent daughter events elsewhere in the region, resulting in the curious rapid subsidence of the Konya Basin within the continuously rising plateau of Türkiye.”

Andersen adds that the new findings suggest a connection between plateau uplift and basin formation events through the evolution of primary and secondary lithospheric removal. “Essentially, subsidence is occurring alongside the ongoing uplifting of the plateau.”

Andersen and study co-authors, including colleagues at Istanbul Technical University and Çanakkale Onsekiz Mart University in Türkiye, arrived at their findings after recreating the dripping process in laboratory experiments and analyzing their observations.

They built laboratory analogue models to establish how the process may have unfolded based on the data provided by the new measurements, filling a plexiglass tank with polydimethylsiloxane (PDMS) – a silicone polymer fluid approximately 1,000 times thicker than table syrup – to serve as Earth’s fluid lower mantle, adding a mixture of PDMS and modelling clay to replicate the upper-most solid section of the mantle, finishing with a sand-like layer on top made from ceramic and silica spheres to serve as Earth’s crust.

Artist’s impression of two types of lithospheric drip: one produces thickening and uplift of Earth’s crust, while the other results in the formation of a basin at the surface without horizontal deformation (illustration by Julia Andersen/University of Toronto)

The researchers activated the model by inserting a high-density seed into the PDMS and modelling clay layer to initiate a drip that was subsequently pulled downward by gravity. A set of cameras were positioned above and beside the tank to record any changes over time, capturing a high-resolution image roughly every minute.

“Within 10 hours, we observed an initial phase of dripping, which we call a primary drip. After that primary drip touched the bottom of the box, we saw a second drip had begun to sink to the bottom after 50 hours,” says Andersen. “Both the primary and secondary drip were not causing any horizontal deformation in our artificial crust, which we expect is typically associated with a mantle lithospheric drip.”

The researchers already knew that the primary drip had caused changes in surface topography of the experiment, and wanted to know if the secondary drip would have any effect on the surface since it was a smaller sized drip than the primary drip. “What we noticed was that over time, this secondary drip did pull the crust downward and started to create a basin, despite no horizontal movements in the crust at the surface,” Andersen says. “The findings show these major tectonic events are linked, with one lithospheric drip potentially triggering a host of further activity deep in the planetary interior.”

Scientists develop framework to measure plastic emissions

Christopher.Sorensen — Mon, 22 Apr 2024 19:43:38 +0000

Scientists develop framework to measure plastic emissions

Christopher.Sorensen Mon, 04/22/2024 - 15:43

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(photo by Alastair Berg via Getty Images)

Sean Bettam

Topic

Our Community

Ecology & Evolutionary Biology

Faculty of Arts & Science

Graduate Students

Sustainability

��ֱ�� Scarborough

Subheadline

Model developed by researchers at ��ֱ�� and the Rochester Institute of Technology suggests that Toronto emitted nearly 4,000 tonnes of plastic pollution in one year alone

Researchers at the University of Toronto have developed a framework for measuring plastic pollution emissions – not unlike the global standard for measuring greenhouse gas emissions.

They say the approach will boost identification of the biggest contributors to plastic pollution from local to national levels and improve strategies in reducing emissions worldwide.

Using Toronto as a model, the first-of-its-kind framework suggests that, in one year alone, Canada’s largest city emitted nearly 4,000 tonnes of plastic pollution.

Alice (Xia) Zhu (supplied image)

“That’s roughly 400 garbage trucks’ worth of plastic that leaks into the environment annually from across the city,” said Alice (Xia) Zhu, lead author of a study outlining the method published in Environmental Science & Technology.

“Assigning responsibility for the pollution to a jurisdiction with the ability to enact laws means there is no hiding where the pollution came from. It presents an opportunity to identify major sources of plastic pollution within the area and inform measures to curb these emissions.”

A PhD candidate in the department of physical and environmental sciences at ��ֱ�� Scarborough who is working with Assistant Professor Chelsea Rochman in ��ֱ��’s department of ecology and evolutionary biology in the Faculty of Arts & Science, Zhu developed the framework with colleagues at ��ֱ�� and the Rochester Institute of Technology. The researchers took inspiration from guidelines for compiling emissions inventories of greenhouse gases established by the United Nations’ Intergovernmental Panel on Climate Change. Adapting for physical differences between greenhouse gases and solid pieces of plastic, the researchers used a similar methodology of identifying the major pollution-generating activities in a particular area, calculating the amount of pollution generated by each activity within a given period and accounting for uncertainties associated with each source of pollution-generating activity.

The framework arrives ahead of international discussions in Ottawa, from April 23 to 29, towards a legally binding global agreement on plastic pollution. The discussions are being led by the UN’s Intergovernmental Negotiating Committee on Plastic Pollution.

Plastic pellets collect around a storm drain near an industrial plant (photo courtesy of ��ֱ�� Trash Team)

“Our goal was to develop an accounting mechanism or tool for measuring plastic emissions that any level of government can adopt,” said Zhu. “But most importantly, we hope this tool we have introduced will allow the plastic field to follow in the footsteps of the climate field, where countries submit national emissions inventories to an international body such as the United Nations to track our progress towards reaching a globally defined target.”

Currently, national emissions inventories of plastic pollution do not exist, nor does a globally defined target for reducing plastic pollution.

Waste from littering, including fragments of foam packaging, accounted for the greatest share of an estimate of plastic pollution in Toronto in 2020 (photo courtesy of ��ֱ�� Trash Team)

To demonstrate the utility of the framework, the researchers built an emissions inventory of plastic pollution for the City of Toronto for the year 2020 that draws from publicly available data gathered through municipal litter audits and other sources. From a list of nine types of sources – including littering, tire dust from airplanes and on-road vehicles, washing machines and paint from road markings and the exteriors of houses – they estimated between 3,531 and 3,852 tonnes of plastic pollution were emitted from within the city’s boundaries during the period.

Littering made up the largest share of the total at 3,099 tonnes, while artificial turf was responsible for the most emissions of microplastics – particles less than five millimetres in diameter – at 237 tonnes.

“It is not surprising that larger materials – known as macroplastics, and in this case from mismanaged waste such as littering – made up the majority of the mass. But it overshadows the small stuff: microplastics,” said Rochman, a co-author of the study and Zhu’s PhD supervisor. “Microplastics tend to be the highest by count in terms of actual pieces. This suggests that policies relevant to microplastics, in addition to macroplastics, are critical to reduce plastic emissions in the City of Toronto.”

Paint peeling from buildings and road markings are significant sources of microplastic pollution (photo courtesy of ��ֱ�� Trash Team)

The researchers selected Toronto to test the framework since it is the largest city in Canada and the fourth-largest city in North America.

“It’s an urban hub for various activities – and where you have lots of people and activity, you inevitably generate a lot of pollution,” said Zhu. “For a successful and informative case study, you want to look at a place with a lot of different sources of pollution. By doing so, you can identify which sources should be prioritized for the reduction of pollution out of all the others, and thereby demonstrate the utility of an emissions inventory for informing local policy.”

Zhu said emissions inventories of plastic pollution must be a foundational piece of a successful global treaty on plastic, and that the framework should be applied to other cities, provinces and states, and countries around the world to better understand what kinds of plastic pollution are being released into the environment.

“The guidelines can be applied to regions worldwide, regardless of what kinds of sources are there,” Zhu said. “Each geographic region will have different characteristics and the inventory will allow for the development of solutions tailored to that specific region.”

Acceleration Consortium funds $1.2 million worth of research projects powered by self-driving labs

Christopher.Sorensen — Wed, 06 Mar 2024 18:35:37 +0000

Acceleration Consortium funds $1.2 million worth of research projects powered by self-driving labs

Christopher.Sorensen Wed, 03/06/2024 - 13:35

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��ֱ�� Engineering researcher Yu Zou’s effort to develop improved materials for hip and knee replacements is among 12 projects receiving funding through the Acceleration Consortium (photo by Neil Ta)

Sean Bettam

Andrea Wiseman

Topic

Our Community

Acceleration Consortium

Institutional Strategic Initiatives

Artificial Intelligence

Chemistry

Computer Science

Faculty of Applied Science & Engineering

Faculty of Arts & Science

��ֱ�� Scarborough

Subheadline

From joint replacements to sustainable chemical manufacturing, ��ֱ�� projects aim to develop new materials that could yield scientific breakthroughs

Canada’s aging population is placing a host of new stressors on the health-care system, including an increasing number of hip and knee replacements that, in a best-case scenario, will last a maximum of 25 years using current materials.

With people living longer, that means there will be more subsequent surgeries to fix or replace the replacements — adding even more stress on the system.

New materials are needed to help solve this problem – and self-driving labs, or SDLs, can help. The labs combine artificial intelligence, robotics and advanced computing to discover new materials and molecules for commercial, clinical and industrial use in a fraction of the usual time and cost.

Yu Zou, an assistant professor in the department of materials science and engineering in the University of Toronto’s Faculty of Applied Science & Engineering, is using an SDL to rapidly test combinations of elements in his quest to develop alloys that can be used in longer-lasting joint replacements.

His work is just one example of the problems being tackled by scientists who have received a total of $1.2 million in Accelerate Grants through the Acceleration Consortium, a ��ֱ�� institutional strategic initiative that is accelerating the discovery of new materials using SDL technologies.

The Acceleration Consortium is funding a diverse array of research efforts across nine departments in the Faculty of Applied Science & Engineering, the Faculty of Arts & Science, the Leslie Dan Faculty of Pharmacy and the University of Toronto Scarborough. Zou’s research is one of 12 new research projects that are either developing technologies that will support the development of SDLs or using SDL technologies to accelerate discovery.

Made possible by the $200 million grant from the Canada First Research Excellence Fund (CFREF) awarded to the Acceleration Consortium last April – the largest federal research grant ever awarded to a Canadian university – the projects enabled by the grant promise innovative advances in fields ranging from health care and climate change to sustainable materials design and food waste management.

“Using AI and automation to carry out more laboratory experiments in a smarter way, we’ve supercharged the process of scientific discovery,” said Alán Aspuru-Guzik¸ director of the Acceleration Consortium and professor in the departments of chemistry and computer science in the Faculty of Arts & Science. “These 12 Accelerate Grants are not only an investment in science, but are an investment in our future.

“The creativity and the diversity of thought shown by the researchers on these projects tells me that the materially different future that the Acceleration Consortium is striving for is achievable in our lifetime.”

The Acceleration Consortium awarded the 12 grants in three categories: Accelerate Seed, which builds accelerated discovery capacity at ��ֱ�� by helping faculty members enter the field or collaborate with those already doing accelerated discovery; Accelerate Moonshot, which support high-risk, high-reward grants that will make significant contributions to the development or use of SDLs; and Accelerate Translation, which support accelerated discovery projects with clear commercialization goals and viable market potential, as well as the implementation or scaling of knowledge mobilization activities, training, and community engagement.

“This suite of Acceleration Grants is an excellent example of how the Acceleration Consortium is advancing the globally recognized strategic research mission of the University of Toronto in a way that’s critical for Canada to remain competitive on the international stage,” said Leah Cowen, ��ֱ��’s vice-president, research and innovation, and strategic initiatives. “By enabling the next generation of scientists to use self-driving labs and fostering research collaboration and partnerships between departments and institutions, these grants will enable the recipients to conduct high-impact, interdisciplinary accelerated research to discover materials that will improve our world.

“I congratulate the principal investigators and their teams who are leading these varied investigations, and I look forward to seeing their results in the accelerated timeline now made possible in part by CFREF and the remarkable demonstration of support for their work.”

While the CFREF funding will help to further advancements made by several researchers who are recognized as leaders in their fields, most support is going to early-career scientists who are pioneering new discoveries just as SDL technology is emerging as a revolutionary approach to knowledge.

Projects dedicated to the continuous improvement of SDL technology are also being funded. For example, a project by Nandita Vijaykumar, an assistant professor in the department of computer and mathematical sciences at ��ֱ�� Scarborough, will develop software that can better manage the fast-flowing data streams SDLs create as well as the resources required to run the experiments.

“The work our grant recipients are doing will help us ensure that the Greater Toronto Area and Canada remain world leaders in AI-frontier discovery,” said Aspuru-Guzik. “And we’re doing so with innovative contributions from people at every stage of their career, with an eye to developing the next generation of groundbreaking researchers along the way. No one is resting on their laurels; each grant recipient and member of the AC is pushing the edge of what is possible and is working towards a materially better future.”

The Acceleration Consortium will welcome proposals for its next funding competition in summer 2024.

Read the story and full list of grant recipients at the Acceleration Consortium

Read the story and full list of grant recipients at the Faculty of Arts & Science

Elite Africa Project shines light on the creativity, expertise and power that thrives on the continent

Christopher.Sorensen — Fri, 23 Feb 2024 19:50:09 +0000

Elite Africa Project shines light on the creativity, expertise and power that thrives on the continent

Christopher.Sorensen Fri, 02/23/2024 - 14:50

Cutline

Students on the upper gallery of the Alioune Diop University Lecture Building in Bambey, Senegal (photo by Chérif Tall/Aga Khan Trust for Culture)

Topic

Faculty of Arts & Science

Subheadline

An international group of African studies scholars has launched the Elite Africa Project, which seeks to redefine the notion of power in Africa and shift public perceptions about the continent’s most prominent and prosperous people.

A global hub of information for scholars, activists, journalists and practitioners, the initiative aims to foster deeper engagement with the expanse of creativity, expertise and power that thrives in Africa today while challenging negative portrayals of the region.

“We’re in a moment where Africans are playing a leading role in almost every field of human endeavor you can imagine,” says Antoinette Handley, a professor in the University of Toronto’s department of political science in the Faculty of Arts & Science who is the project’s principal investigator.

“For example, several of the world’s top prizes for literature have gone to a range of African authors in recent years, the 2022 Pritzker Architecture Prize was awarded to a native of Burkina Faso – the first African and first Black architect to receive the honour — the World Health Organization is currently headed by an Ethiopian public health researcher and the World Trade Organization is headed up by the former finance minister of Nigeria.”

In addition to Handley and fellow ��ֱ�� scholars Dickson Eyoh, Sean Hawkins and Nakanyike B. Musisi, the project is led by Gerald Bareebe of York University, Peter Lewis of Johns Hopkins University, Landry Signé of Arizona State University and the Brookings Institution and Thomas Kwasi Tieku of King’s University College at Western University.

Despite the many achievements emerging from across the world’s second-most populous continent, the researchers say most popular and academic treatments of Africa tend to feature people commonly regarded as weak and poor or villainous and despotic.

Calling for a reassessment of former approaches, the scholars’ aims are to:

Challenge the narrow and sometimes racist popular understanding that the continent is composed largely of poor or disempowered populations and a class of individuals who are either corrupt, self-serving or puppets of international forces.
Map the dynamics of elite formation in Africa.
Present power as more multidimensional: comprising “soft” forms of power such as knowledge, skills and creativity, as much as it also comprises the more commonly considered “hard” forms of power, such as coercion or material resources.

“Ultimately, our goal with the Elite Africa Project – aptly named to refer to the people who are unusually influential in agenda-setting and decision-making – is to challenge academic and public perceptions of influential Africans as grasping and self-interested, a framing that perpetuates negative depictions of the continent and its peoples and draws on a simplistic understanding of power and how it is wielded,” Handley said.

“Our focus is on the burgeoning ranks of globally renowned artists, prominent intellectuals, innovative businesspeople, accomplished scientists and many others who are flourishing and, in the process, transform both Africa and the global fields within which they work.”

Clockwise from top left: Antoinette Handley, Dickson Eyoh, Sean Hawkins, Nakanyike Musisi, Thomas Kwasi Tieku, Landry Signé, Peter Lewis and Gerald Bareebe (photos courtesy of Elite Africa Project)

The project’s central feature is a database curated primarily for scholars and students of African studies that’s designed to be an entry point into more research about – and a better understanding of – elites and elite accomplishments across the continent.

“With the help of our team from across the globe, we're building an essential hub of information for scholars, activists, journalists and practitioners – anyone intrigued by Africa's vibrant domains ranging from politics and economics to religion and the arts, and everything in between,” said Eyoh, an associate professor in ��ֱ��’s department of political science in the Faculty of Arts & Science and the African Studies Centre at New College.

The database contains key academic works, a curated assortment of relevant podcasts and videos, and a collection of biographies of personalities and organizations.

“Whether someone is looking for information about highly regarded African photographers or fashion designers, or some background on the political history of any one African nation, or the roles of religious leaders across many African societies, our hope is that the database can serve as a starting point or a source of supplementary information in the course of their investigation,” Handley said. “It could also be used as a teaching tool for students at any level.”

Another key feature of the project’s website is a weekly roundup of news articles offering insights into a wide variety of people, places and proceedings making headlines both domestically and internationally.

“We're very conscious about presenting items that are not just limited to politics or big economic stories, but represent accomplishments by leading Africans in every imaginable sphere of human activity,” said Handley.

“There’s a huge amount of news stories and data about Africa out there – we’re trying to present a shorthand, easy overview that provides a more well-rounded picture. It lands in your Instagram feed once a week and you can keep track broadly of what’s happening on the continent.”

Handley says her hope for the project is “to go beyond negative stereotypes and ensure a broader, balanced, perhaps more positive view of all that Africa has to offer.”

Ancient ape from Türkiye challenges the story of human origins, researchers say

Christopher.Sorensen — Thu, 24 Aug 2023 14:55:53 +0000

Ancient ape from Türkiye challenges the story of human origins, researchers say

Christopher.Sorensen Thu, 08/24/2023 - 10:55

Cutline

A new face and partial brain case of Anadoluvius turkae, a fossil hominine – the group that includes African apes and humans – from the Çorakyerler fossil site located in Central Anatolia region of Türkiye (photo by Sevim-Erol, A., Begun, D.R., Sözer, Ç.S. et al.)

Sean Bettam

Topic

Breaking Research

Anthropology

Faculty of Arts & Science

Global

Research & Innovation

Subheadline

Analysis of a newly identified ape fossil at 8.7-million-year-old site suggests the ancestors of African apes and humans evolved in Europe before migrating to Africa

A new fossil ape from an 8.7-million-year-old site in Türkiye is challenging long-accepted ideas of human origins and adding weight to the theory that the ancestors of African apes and humans evolved in Europe before migrating to Africa between nine and seven million years ago.

Analysis of a newly identified ape named Anadoluvius turkae, recovered from the Çorakyerler fossil site near Çankırı with the support of the Ministry of Culture and Tourism in Türkiye, shows Mediterranean fossil apes are diverse and part of the first known radiation of early hominines – the group that includes African apes (chimpanzees, bonobos and gorillas), humans and their fossil ancestors.

A new study published in the journal Communications Biology describes the findings. It was co-authored by an international team of researchers led by researchers David Begun at the University of Toronto and Ayla Sevim Erol at Ankara University.

Excavation of the Anadoluvius turkae fossil, a significantly well-preserved partial cranium uncovered at the Çorakyerler fossil site in Türkiye in 2015. The fossil includes most of the facial structure and the front part of the brain case (photo by Ayla Sevim-Erol)

“Our findings further suggest that hominines not only evolved in western and central Europe but spent over five million years evolving there and spreading to the eastern Mediterranean before eventually dispersing into Africa – probably as a consequence of changing environments and diminishing forests,” said Begun, a professor in the department of anthropology in ��ֱ��’s Faculty of Arts & Science. “The members of this radiation to which Anadoluvius belongs are currently only identified in Europe and Anatolia.”

The conclusion is based on analysis of a significantly well-preserved partial cranium uncovered at the site in 2015, which includes most of the facial structure and the front part of the brain case.

“The completeness of the fossil allowed us to do a broader and more detailed analysis using many characters and attributes that are coded into a program designed to calculate evolutionary relationships,” said Begun. “The face is mostly complete after applying mirror imaging. The new part is the forehead, with bone preserved to about the crown of the cranium. Previously described fossils do not have this much of the brain case.”

The Çorakyerler excavation site near Çankırı, Türkiye is one of the most important humanoid settlements in Eurasia (photo by Ayla Sevim-Erol)

The researchers say Anadoluvius was about the size of a large male chimpanzee (50-60 kilograms) – very large for a chimp and close to the average size of a female gorilla (75-80 kilograms) – lived in a dry forest setting and probably spent a great deal of time on the ground.

“We have no limb bones, but judging from its jaws and teeth, the animals found alongside it and the geological indicators of the environment, Anadoluvius probably lived in relatively open conditions unlike the forest settings of living great apes – more like what we think the environments of early humans in Africa were like,” said Ankara University’s Sevim Erol. “The powerful jaws and large, thickly enamelled teeth suggest a diet including hard or tough food items from terrestrial sources such as roots and rhizomes."

The animals that lived with Anadoluvius are those commonly associated with African grasslands and dry forests today such as giraffes, warthogs, rhinos, diverse antelopes, zebras, elephants, porcupines, hyenas and lion-like carnivores. Research shows that the ecological community appears to have dispersed into Africa from the eastern Mediterranean more than eight million years ago.

“The founding of the modern African open-country fauna from the eastern Mediterranean has long been known and now we can add to the list of entrants the ancestors of the African apes and humans,” said Sevim Erol.

The findings establish Anadoluvius turkae as a branch of the part of the evolutionary tree that gave rise to chimpanzees, bonobos, gorillas and humans. Although African apes today are only known from Africa, as are the earliest known humans, the study’s authors – which also include colleagues at Ege University and Pamukkale University in Türkiye and the Naturalis Biodiversity Center in the Netherlands – conclude that the ancestors of both came from Europe and the eastern Mediterranean.

Excavation of the Anadoluvius turkae fossil took place at the Çorakyerler fossil site in Türkiye in 2015 (image by David Begun/Google Earth)

Anadoluvius and other fossil apes from nearby Greece (Ouranopithecus) and Bulgaria (Graecopithecus) form a group that come closest in many details of anatomy and ecology to the earliest known hominins, or humans. The new fossils are the best-preserved specimens of this group of early hominines and provide the strongest evidence to date that the group originated in Europe and later dispersed into Africa.

Çorakyerler is located in Çankırı province in Türkiye 's Central Anatolia Region (photo by Ayla Sevim Erol)

The study’s detailed analysis also reveals that the Balkan and Anatolian apes evolved from ancestors in western and central Europe. With its more comprehensive data, the research provides evidence that these other apes were also hominines and suggests it is more likely that the whole group evolved and diversified in Europe, rather than the alternative scenario in which separate branches of apes earlier moved independently into Europe from Africa over the course of several million years and then went extinct.

“There is no evidence of the latter, though it remains a favourite proposal among those who do not accept a European origin hypothesis,” said Begun. “These findings contrast with the long-held view that African apes and humans evolved exclusively in Africa. While the remains of early hominines are abundant in Europe and Anatolia, they are completely absent from Africa until the first hominin appeared there about seven million years ago.

“This new evidence supports the hypothesis that hominines originated in Europe and dispersed into Africa along with many other mammals between nine and seven million years ago, though it does not definitively prove it. For that, we need to find more fossils from Europe and Africa between eight and seven million years old to establish a definitive connection between the two groups.”

Smartphone app designed by ��ֱ�� researchers can significantly improve memory recall

Christopher.Sorensen — Mon, 16 Jan 2023 16:13:24 +0000

Smartphone app designed by ��ֱ�� researchers can significantly improve memory recall

Christopher.Sorensen Mon, 01/16/2023 - 11:13

Cutline

Psychology post-doctoral researcher Bryan Hong and Professor Morgan Barense review fMRI scans in the Toronto Neuroimaging Facility (photo by Diana Tyszko)

Topic

Faculty of Arts & Science

Memory

Psychology

Research & Innovation

Startups

UTEST

Researchers at the University of Toronto have demonstrated that a new smartphone application helps to significantly improve memory recall, which could prove beneficial for individuals in the early stages of Alzheimer’s disease or other forms of memory impairment.

Dubbed HippoCamera for its ability to mimic the function of the brain’s hippocampus in memory construction and retention, the app enhances the encoding of memories stored in the brain by boosting attention to daily events and consolidating them more distinctly – thus later enabling richer, more comprehensive recall.

In a two-step process, HippoCamera users record a short video of up to 24 seconds of a moment they want to remember with a brief eight-second audio description of the event. The app combines the two elements just as the brain’s hippocampus would, with the video component sped up to mimic aspects of hippocampal function and to facilitate efficient review. Users then replay cues produced by HippoCamera at later times on a curated and regular basis to reinforce the memory and enable detailed recall.

“We found that memories with an associated HippoCamera cue were long-lasting, and that it worked for everyone in the study – healthy older adults, those starting to show cognitive decline and even one case with severe amnesia due to an acquired brain injury,” said study co-author Morgan Barense, a professor in the department of psychology in ��ֱ��’s Faculty of Arts & Science and Canada Research Chair in Cognitive Neuroscience.

Morgan Barense

“Many months after the initial part of the study ended, and participants had not watched their HippoCamera cues, they were able to recall these memories in rich detail.”

The study, published in the Proceedings of the National Academy of Sciences, shows that regular users of the app were able to recall over 50 per cent more details about everyday experiences that took place as many as six months earlier than if they had only recorded events and never replayed them. The new research suggests that systematic reactivation of memories for recent real-world experiences can help to maintain a bridge between the present and past in older adults and holds promise for people in the early stages of Alzheimer’s disease or other forms of memory impairment.

The study also found that reviewing memory cues with HippoCamera resulted in more positive sentiment during later retrieval.

“There’s something about being better able to remember these events that made people feel closer to them and more positive,” said Barense, who is leading the development of the app and is adjunct scientist at the Rotman Research Institute at Baycrest. “This is a really important finding given what we know about dementia and the fact that positive reminiscence or focusing on positive life events and positive emotions can improve both memory and well-being in dementia.”

The researchers measured study participants’ patterns of brain activity using fMRI, showing that recall-related brain activity in the hippocampus was more distinctive due to HippoCamera use (photo by Diana Tyszko)

For the study, participants recorded unique HippoCamera clips for everyday events that they wanted to remember and subsequently replayed these memory cues approximately eight times over a two-week period in one experiment, and over a 10-week period in a second experiment. The researchers then initiated a cued recall task where they showed the participants their memory cues and asked them to describe everything they could remember about each event.

This was followed by fMRI brain scanning sessions where researchers measured patterns of brain activity while participants saw their cues and completed a memory test. Three months later, after not practising their HippoCamera memories and not having access to the cues, the participants were asked to recall these events a second time.

“On average, we saw on later recall an increase of more than 50 per cent in the amount of rich, detailed information that someone was able to remember about events that happened as many as 200 days ago, which is significant,” said Chris Martin, an assistant professor in the department of psychology at Florida State University and lead author of the study. “Memory is truly self-sustaining ⁠– a strong memory cue can bring along another memory, which can feed into another. You just have to focus on the cue in the first place.”

Bryan Hong replays a memory cue captured using HippoCamera, which combines short audio and video clips of an event just as the hippocampus would (photo by Diana Tyszko)

The brain scans showed that replaying HippoCamera memory cues changed the way in which these everyday experiences were coded in the hippocampus, which has a well-established role in storing detailed memories for recent experiences. Recall-related activity in the hippocampus was more distinctive, meaning that HippoCamera replay helps to ensure that memories for different events remain separate from one another in the brain.

“The more detailed recollection seen earlier in the study was associated with more differentiated memory signals in the hippocampus,” said Martin. “That HippoCamera is aiding the hippocampus in distinctly encoding memories, so they do not become confused with one another, explains why users are able to recall past events in such great detail. It’s evidence that rich and detailed memory reactivation promotes memory differentiation at the neural level, and that this allows us to mentally re-experience the past with vivid detail.”

One key factor in HippoCamera’s effectiveness, the researchers say, is the sense of purpose and intention inherent in its use. By its very design, the intervention prompts users to think about what it is that they want to remember and why a particular moment is important to them – and then regularly re-engage with the memories in a meaningful way.

With an easy-to-use interface, HippoCamera is a personalized way to boost recall of daily experiences and enhance activity in the hippocampus, a part of the brain that plays a key role in memory (photo courtesy of Dynamic Memory Solutions Inc.)

“Someone who is committed to using HippoCamera is going to go through their lives paying attention to what is happening to them, asking themselves if this is an event they want to capture,” said Barense. “If it is, they’re going to take the time to stop and describe that event. And that act of approaching events in our lives with more attention is going to be good for memory.

“Then later, there’s an intention with how we study those memories, taking the time to review them using optimal learning techniques.”

The researchers note that as people begin to lose their existing memories at any point in their lives, as well as their ability to create new ones, they start to lose their sense of self. As a result, they often become disengaged from the people and events in their lives.

“Memory and our sense of identity are very closely linked,” said Barense, who is receiving support from ��ֱ�� startup accelerator UTEST to take the app from lab to market. “We understand who we are as people by remembering the things that we’ve done. Our hope with HippoCamera is that by helping people feel closer to these people and events in their lives, we can help give them back their sense of self.”

The research was supported by the Canadian Institutes for Health Research, among others.

Researchers discover what causes some icicles to form with ripples

Christopher.Sorensen — Thu, 01 Dec 2022 16:03:49 +0000

Researchers discover what causes some icicles to form with ripples

Christopher.Sorensen Thu, 12/01/2022 - 11:03

Cutline

An icicle cross section under polarized light, showing the crystal structure of the ice shot through with dark regions of unfrozen, impure water (all images courtesy of J. Ladan and S. W. Morris)

Sean Bettam

Topic

Breaking Research

Faculty of Arts & Science

Physics

Research & Innovation

Experimental physicists at the University of Toronto are closer to understanding why some icicles form with ripples up and down their outsides, while others form with smooth, slick, even surfaces.

By growing icicles from water samples with different contaminants like sodium chloride (salt), dextrose (sugar) and fluorescent dye, the researchers discovered that water impurities become entrapped within icicles as they form and subsequently create chevron patterns that contribute to a ripple effect around their circumferences.

The findings were described in a study published recently in Physical Review E.

A series of icicle cross sections at increasing concentration of salt. In the mid-range, a clear chevron pattern of fogginess is seen that matches up with the surface ripples.

“Previous theories held that the ripples are the result of surface tension effects in the thin film of water that flows over the ice as it forms,” says Stephen Morris, a professor emeritus in the department of physics in the Faculty of Arts & Science and a co-author of the study. “We now see that the ripple formation does not depend on surface tension. It does not even depend only on features external to the ice, but rather is connected to patterns of impurities inside the ice.

The cross section of an icicle, showing the pattern of internal fogginess, overlaid by edges measured during the growth. The red dots indicate the troughs of ripples.

"The external shape and internal patterns are different aspects of the same – so far unexplained – problem.”

The findings build on an earlier discovery by Morris and his research team that found the presence of salt in water was responsible for the irregular, rippled shapes of icicles grown in the lab. The new results show that it is not the type of impurity that leads to the ripples, but just the fact that there is something foreign in the water.

“We tested various species of impurities and the phenomena are unchanged as long as their concentrations are similar,” says John Ladan, a PhD student working with Morris and lead author of the study. “This is consistent with the idea that only physical, as opposed to chemical, processes are involved.”

While their motivation for unlocking the secret behind the ripples is pure curiosity about natural patterns, the study of ice growth has serious applications, including ice accumulation on airplanes, ships and power lines. However, the results show that existing engineering models of ice accretion on power lines do not account for the entire problem. The researchers note that the findings do not resolve the mechanism of the ripples, but rather just add new aspects to the phenomena to be explained.

“We get a more profound appreciation for the complexity of natural ice formations,” says Morris.

With files from the American Physical Society.

Researchers identify mechanism responsible for temperature and salinity 'staircases' in Arctic Ocean

Christopher.Sorensen — Wed, 28 Sep 2022 19:08:56 +0000

Researchers identify mechanism responsible for temperature and salinity 'staircases' in Arctic Ocean

Christopher.Sorensen Wed, 09/28/2022 - 15:08

Cutline

Understanding how temperature and salinity “staircases” form could shed more light on the causes and consequences of rapid Arctic sea ice loss amid climate change (photo by imagebear via Getty Images)

Topic

Faculty of Arts & Science

Graduate Students

Physics

Research & Innovation

Sustainability

Researchers at the University of Toronto have identified the mechanism responsible for the formation of temperature and salinity “staircases” in the Arctic Ocean, resolving a mystery that has confounded oceanographers and climatologists alike for more than half a century.

Understanding how these vertical structures work promises to shed more light on the causes and consequences of rapid Arctic sea ice loss amid climate change.

“Our discovery of a new mechanism of hydrodynamic instability provides insights into the formation of staircase-like structures resulting from the mixing of warm salt water and cooler fresh water,” said Yuchen Ma, a PhD candidate in the department of physics in the Faculty of Arts & Science and lead author of a study published in Physical Review Fluids describing the findings.

“These structures were first observed in the late 1960s but the mechanism responsible for their existence has never been explained.”

Known as thermohaline staircases, these step-like variations of temperature and salt concentration are common in a wide range of regions of the global ocean.

A simulation depicts the strongly defined changes in temperature and salt that form staircase-like structures within the Arctic Ocean (image courtesy of Yuchen Ma and W. Richard Peltier)

The findings reported in Physical Review Fluids – which have attracted significant positive response from the research community – fully verify a previous analysis by the same authors published in the Journal of Fluid Mechanics in 2020 that documented the existence of this new hydrodynamic instability. The verification was accomplished by designing a series of direct numerical simulations of turbulence in the Arctic Ocean to better understand global ocean circulation.

“The ocean is typically thought of as a highly chaotic and turbulent environment, so it is striking to see such strongly defined layers of salt and heat within it,” says Ma.

The flow of heat out of the ocean into the overlying sea ice is strongly enhanced by the presence of thermohaline staircases. Thus, understanding the staircase formation process in the polar oceans is important for developing future global warming projections and informing efforts to mitigate sea ice loss.

“In this era of global warming, it is a well-recognized fact that the loss of Arctic Ocean sea ice cover is a critical aspect of this global process,” said University Professor W. Richard Peltier, of the department of physics who is a co-author of the studies and Ma’s PhD supervisor.

“While the extent to which staircase formation is contributing to this loss has yet to be quantified, we can certainly say that the ocean component of the climate models employed to make projections of the global warming process are not able to resolve the staircase formation process.”

The research builds on previous work that focused on understanding global ocean circulation under the ice age conditions from 30,000 to 70,000 years ago.

In the previously developed model of glacial climate, the rapid transitions from cold to warm weather were shown to be caused by an extensive “hole” in the sea ice cover of the North Atlantic Ocean resulting from heat flow out of the ocean into the sea ice. The magnitude of this heat flow was determined by the assumption that a staircase had formed in the ocean below.

Support for the research was provided by the Natural Sciences and Engineering Research Council of Canada. The computations on which the study is based were performed on the Niagara supercomputer cluster at the SciNet High Performance Computing facility at ��ֱ��, which is funded by the university, the Canadian Foundation for Innovation and the Province of Ontario.

Up a creek without a paddle? Researchers suggest 'gunwale bobbing'

Christopher.Sorensen — Thu, 04 Aug 2022 17:07:40 +0000

Up a creek without a paddle? Researchers suggest 'gunwale bobbing'

Christopher.Sorensen Thu, 08/04/2022 - 13:07

Cutline

��ֱ��'s Stephen Morris published a study with international researchers that investigated how "gunwale bobbing," as demonstrated in this photo of one of the investigators' children, moves a craft forward (photo courtesy of G. P. Benham et al.)

Sean Bettam

Topic

Breaking Research

Faculty of Arts & Science

Physics

Research & Innovation

Stand up in a canoe and you’ll probably find yourself in the water before too long. Jump up and down on the upper edges of the sides of the canoe, and you’ll likely end up in the drink as well. But get the balance right and you’ll be able to move yourself along by as much as one metre per second, according to a study published in Physical Review Fluids examining gunwale bobbing.

In gunwale (pronounced “gunnel”) bobbing, a canoeist stands on the sides of the canoe – the gunwales – near the rear of the craft and jumps up and down, moving it forward by surfing the waves produced.

After an initial period of instability before finding its rhythm, the canoe achieves a cruising velocity which satisfies a balance between the thrust generated from pushing downwards into the surface of the waves and the resistance caused by drag. The technique also works on stand-up paddle boards.

“People have long enjoyed gunwale bobbing as something fun to do when out on the water, but no one has ever really explained how it works,” says Stephen Morris, a professor emeritus in the department of physics in the Faculty of Arts & Science and co-author of the study describing the phenomenon. “By drawing on long-standing linear wave and oscillation theories, we’ve figured out how such balance can be sustained.”

Searching for the perfect combination of forward, backward, up and down motions, Morris and colleagues at the University of Cambridge, Oxford University and the University of Paris created a theoretical model to describe the wave field produced. They then compared it to data taken from an enthusiastic gunwale bobber crossing a body of water in a canoe using waves created when its two ends pitch up and down.

In a symmetric system where a canoeist’s body pitches forward and backward in equal measure – think of the rhythmic motion of a rower’s body in Olympic competition – the waves generated cause the vessel to oscillate back and forth with no net motion. But in an asymmetric system, such as that created when a person imparts a vertical displacement such as by jumping up and down out of phase with the pitch of one end of the vessel, the vehicle gains a net thrust.

The researchers calculated the optimal values of the four motions involved to achieve maximum velocity and, using their model, determined the technique could propel a typical canoe at steady speeds of up to about one metre per second – comparable to speeds observed for gunwale bobbing with real canoes.

“Understanding gunwale bobbing could be useful in competitive water sports like rowing,” says Morris. “Because rowers generate periodic downward forces, like jumping on gunwales does, it might be possible to optimize rowing strokes, so the boat interacts with the waves it generates in a way that helps push it forward.”

With files from the American Physical Society

The Earth's crust has been 'dripping' beneath the Andes Mountains for millions of years: Researchers

geoff.vendeville — Tue, 19 Jul 2022 15:41:12 +0000

The Earth's crust has been 'dripping' beneath the Andes Mountains for millions of years: Researchers

geoff.vendeville Tue, 07/19/2022 - 11:41

Cutline

Salar de Arizaro in the Atacama Desert (photo by Nicolas de Camaret, CC BY 2.0, via Wikimedia Commons)

Sean Bettam

Topic

Breaking Research

Earth Sciences

Faculty of Arts & Science

Research & Innovation

Just like honey slowly dripping from a spoon, parts of the rocky outermost layer of Earth’s shell are continuously sinking into the more fluid layer of the planet’s mantle over the course of millions of years. Known as lithospheric dripping – named for the fragmenting of rocky material that makes up Earth’s crust and upper mantle – the process results in significant deformations at the surface such as basins, folding of the crust and irregular elevations.

Though the process is a relatively new concept in the decades-old field of plate tectonics, several examples of lithospheric drip around the world have been identified – the Central Anatolian Plateau in Turkey and the Great Basin in the western U.S., for two. Now, a team of researchers led by Earth scientists at the University of Toronto has confirmed that several regions in the central Andes Mountains in South America were formed the same way.

And they’ve done so using materials available at any hardware store and art supplies outlet.

“We have confirmed that a deformation on the surface of an area of the Andes Mountains has a large portion of the lithosphere below avalanched away,” says Julia Andersen, a PhD candidate in the department of Earth sciences at ��ֱ�� and lead author of a study published in Communications Earth & Environment, part of the Nature family of journals. “Owing to its high density, it dripped like cold syrup or honey deeper into the planetary interior and is likely responsible for two major tectonic events in the Central Andes – shifting the surface topography of the region by hundreds of kilometres and both crunching and stretching the surface crust itself.

“Overall, the results help define a new class of plate tectonics and may have implications for other terrestrial planets that do not have Earth-like plate tectonics such as Mars and Venus.”

A geological map of the Arizaro Basin, demonstrating folding and thrust faults within the basin, as compared with surface view of the experimental simulation of lithospheric dripping. Folding and direction of shortening is depicted with red arrows (left photo courtesy of DeCelles, et al.; right courtesy of Julia Andersen et al.)

Lithospheric dripping occurs when portions of the lowest layer of Earth’s outer shell thicken and begin to drip into the mantle below when warmed to a certain temperature.

As the fragments sink into the lower mantle, it first forms a basin at the surface which later springs up when the weight below breaks off and sinks further into the deeper depths of the mantle. This results in an upward bobbing of the land mass across hundreds of kilometres.

The Central Andean Plateau is defined by the Puna and Altiplano high plateaus and was first formed when the Nazca plate slid beneath the South American plate during the well-documented plate tectonics process of subduction, during which a portion of the heavier of two tectonic plates sinks into the mantle when they converge.

Past studies have suggested, however, that the subsequent rise of Central Andean topography has not been uniform in time but rather was built through sporadic pulses of uplift throughout the Cenozoic Era that began approximately 66 million years ago.

Geological estimates indicate that the relative timing and mechanism of uplift in the region and the styles of tectonic deformation are different between the Puna and Altiplano plateaus. The Puna Plateau is characterized by higher average elevation and includes several isolated inland basins, such as the Arizaro Basin and the Atacama Basin, and distinct volcanic centres.

“Various studies invoke removal of the lithosphere to account for the widespread, non-subduction related surface deformation and evolution of the plateaus,” says Earth sciences Professor Russell Pysklywec, co-author of the study and Andersen’s PhD supervisor. “Further, crustal shortening in the Arizaro Basin interior is well documented by folding and local thrust faults but the basin is not bounded by known tectonic plate boundaries, indicating there is a more localized geodynamic process occurring.”

Geoscientists have used the sedimentary rock record to track changes in surface elevation of the Central Andes since the Miocene epoch approximately 18 million years ago. Seismic imaging provides a remote image of Earth’s interior much like an ultrasound for a human body, illuminating a new view of the lithospheric drip structures.

A simulation of the rocky outermost layer of Earth’s shell using silicone polymer fluid, modelling clay, and a sand-like layer made from ceramic and silica spheres demonstrates the process of lithospheric dripping. (photo by Julia Andersen/Tectonophysics Lab/University of Toronto)

Andersen and her colleagues say past geological studies advance evidence for lithospheric drips in the region, but the dynamical processes of lithospheric dripping and their role in driving local surface tectonics in these purported geological cases are uncertain. For the most part, geodynamic model predictions have not been tested in the context of direct regional geological or geophysical observations.

So, the team set about developing analogue laboratory models with geological and geophysical constraints to recreate what happened over thousands of centuries and test their hypothesis that the topographic and tectonic evolution of hinterland basins of the Central Andes was caused by lithospheric drip processes.

“Recognizing the massive time and length scales involved in these processes – millions of years and hundreds of kilometres – we devised innovative three-dimensional laboratory experiments using materials such as sand, clay and silicone to create scaled analogue models of the drip processes,” Andersen says. “It was like creating and destroying tectonic mountain belts in a sandbox, floating on a simulated pool of magma – all under incredibly precise sub-millimetre measured conditions.”

The models were constructed inside a Plexiglass tank with a set of cameras positioned above and beside the tank to capture any changes. The tank was first filled with polydimethylsiloxane (PDMS) – a silicone polymer fluid approximately 1,000 times thicker than table syrup – to serve as Earth’s lower mantle. Next, the upper-most solid section of the mantle was replicated using a mixture of PDMS and modelling clay and put into the tank on top of the mantle. Finally, a sand-like layer made from a mixture of precision ceramic spheres and silica spheres was laid on top to serve as Earth’s crust.

The researchers activated the model by inserting a high-density seed into the PDMS and modelling clay layer, to initiate a drip that was subsequently pulled downward by gravity. The cameras outside the tank ran continuously, capturing a high-resolution image roughly every minute.

“The dripping occurs over hours so you wouldn’t see much happening from one minute to the next,” Andersen says. “But if you checked every few hours, you would clearly see the change – it just requires patience.” The study presents snapshots from every 10 hours to illustrate the progress of the drip.

The researchers then cross-referenced the size of the drip and the damage to the replica crust at select time intervals to see how their scaled processes matched up against the sedimentary records of the areas in question over millions of years.

Artist impressions of two types of lithospheric drip, supported by surface views of the experimental simulation of the processes. One produces thickening and uplift of Earth’s crust, while the other results in the formation of a basin at the surface (photo by Julia Andersen/Tectonophysics Lab/University of Toronto)

“We compared our model results to geophysical and geological studies conducted in the Central Andes, particularly in the Arizaro Basin, and found that the changes in elevation of the crust caused by the drip in our models track very well with changes in elevation of the Arizaro Basin,” Andersen says. “We also observed crustal shortening with folds in the model as well as basin-like depressions on the surface so we’re confident that a drip is very likely the cause of the observed deformations in the Andes.”

The researchers suggest the findings aim to clarify the link between mantle processes and crustal tectonics, and how such geodynamic processes may be interpreted with observed or inferred episodes of lithospheric removal. “The discoveries show that the lithosphere can be more volatile or fluid-like than we believed,” says Pysklywec.

Additional contributors to the study include Tasca Santimano, of ��ֱ��'s department of Earth sciences, and Oguz Göğüş at Istanbul Technical University and Ebru Şengül Uluocak at Çanakkale Onsekiz Mart University in Turkey.

The research was made possible thanks to support from a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada, the International Fellowship for Outstanding Researchers Programme of the Scientific and Technological Research Council of Turkey, a TUBITAK Fellowship for Visiting Scientists, as well as Compute Ontario and the Digital Research Alliance of Canada.

Sean Bettam

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