COMMUNITY OWNED FOOD CO-OPS

Fresh and healthy food can be difficult for some Montrealers to access, new Concordia study shows

The researchers say city planners must support the development of more grocery stores and improve transportation options in food deserts

Concordia University

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Sepideh Khorramisarvestani

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Credit: Concordia University

Fresh, affordable and nutritious food is an essential human need. But for many city-dwellers, accessing it can be difficult and time-consuming, especially for those who are elderly or have mobility challenges. This is true even in Montreal, a city that prides itself on its active transportation network and compact population distribution.

In a new study published in the Journal of Urban Mobility, Concordia researchers examine how walking, cycling and public transit shape access to fresh and healthy food.

They found that nearly half of Montrealers do not have adequate access to fresh food sources like grocery stores or produce markets within a 10-minute walk from their home or place of work. That number improves for cyclists, but the researchers say the best chance of accessing healthy food comes from a combination of active transportation and public transit.

“We wanted to better understand the connection between public transportation and daily needs,” says the study’s lead author Sepideh Khorramisarvestani, a PhD candidate in the Department of Geography, Planning and Environment. “These results show us that we can greatly increase accessibility to healthy food by locating grocery stores close to public transit. This ensures people can get necessities on their way home from work.”

Options by foot, bike or transit

The researchers used an advanced routing algorithm to develop their model. They mapped where people live at the city-block level and matched this with the verified locations of nearly 1,000 healthy food establishments, such as grocery stores and fruit and vegetable markets. Convenience stores and restaurants were excluded from the study, since the nutritional value of the food they offer is inconsistent.

The algorithm calculated how many healthy food stores residents could reach using three travel scenarios: walking only, cycling only and a combination of walking or cycling plus public transit. Travel times included realistic factors such as walking to transit stops, waiting, transfers and final walking distances.

Areas where five or more stores were located along a given travel route were considered to have strong access. Areas with two or fewer stores were considered to have poor access.

The researchers considered a healthy food establishment “locally accessible” if it was within a 10-minute walk or bike ride from home or work, assuming the person is a healthy, able-bodied adult. For longer trips, they used a 30-minute window that combined active travel with public transit.

As expected, neighbourhoods in Montreal’s downtown core and other densely populated areas near the city centre had adequate to good access to fresh, healthy food. Proximity to metro lines, busy commercial streets and strong walking, cycling and transit facilities characterized these areas.

Less well-served areas include neighbourhoods in western and southwestern Montreal, Montréal-Nord, as well as eastern and suburban areas, which offered poor access for walking alone. These neighbourhoods were characterized by fewer grocery stores, lower street connectivity and longer distances between transit stops.

Neighbourhoods with continuous bike paths also scored better.

Putting groceries near transit stops

The researchers conclude that improving access to fresh, healthy food requires coordinated land- and transportation planning. This approach could involve broadening cycling networks or improving and expanding public transit. They also suggest creating mobility hubs that feature transit stops, pedestrian and cycling facilities and grocery stores.

Khorramisarvestani says she plans to continue studying how Montreal is organized, including a closer look at grocery store locations and how local amenities are connected under different parameters.

“The concepts of the 15-minute city and proximity planning are becoming increasingly popular,” she says. “We want to understand how realistic they are to achieve.”

This research was funded by the Fonds de recherche du Québec and the Natural Sciences and Engineering Research Council of Canada.

The study was co-authored by Pierre Gauthier, an associate professor in the Department of Geography, Planning and Environment, and Ursula Eicker, a professor in the Department of Building, Civil and Environmental Engineering.

Read the cited paper: “Exploring sustainable accessibility through multimodal networks: Assessing heathy food access in Montreal”.

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Journal

Journal of Urban Mobility

DOI

10.1016/j.urbmob.2025.100170 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Exploring sustainable accessibility through multimodal networks: Assessing healthy food access in Montreal

 

Why parents turn to social media about kids’ drug use

UTA-linked study finds peer advice on social platforms can confuse and lack evidence

University of Texas at Arlington

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University of Texas at Arlington Professor Dana Litt contributed to a study led by Alex Russell, assistant professor at Harvard Medical School, that found many parents turn to online peer advice when facing concerns about substance use among their children.

While parents often value guidance from others with similar experiences, the study found that much of the advice can be confusing, contradictory, and lacking an evidence-based foundation.

“We were motivated by the recognition that parents play a critical role in shaping children’s substance-related attitudes and behaviors, yet many report feeling uncertain or underprepared when these issues arise,” said Dr. Litt, professor of social work and co-director of UTA’s Studying Alcohol and Related Risks (STARR) Lab. “Because social media platforms such as Reddit offer anonymity and peer support, they provide a unique window into parents’ real-world concerns and informational needs that may not surface in clinical or research settings.”

The study, published in the Journal of Studies on Alcohol and Drugs, noted that peer exchanges should “complement rather than replace evidence-based guidance.”

Researchers analyzed posts from a popular Reddit parenting forum spanning June 2009 to September 2024. Using targeted keywords, they identified roughly 3,500 posts related to parental concerns about substance use, then selected 156 that reflected a “range of complex and emotionally difficult situations.”

The study found parents often seek advice reactively rather than proactively and that many posts contained misconceptions.

For example, parents suggested that allowing adolescents to use substances under adult supervision could promote safer habits—an idea that runs counter to evidence-based research showing early initiation and parental permissiveness are linked to poorer outcomes.

Similarly, public attitudes toward cannabis have grown more favorable, yet adolescent use remains associated with significant developmental, cognitive, and mental health risks.

“In order to address these misconceptions, we have to meet parents where they are by translating evidence-based guidance into clear, empathetic, and easily shareable messages that resonate with parents’ real concerns,” Litt said. “Many evidence-based resources can feel abstract, overly clinical, and difficult to navigate and can be expensive to access. Online communities, on the other hand, offer validation and practical advice from other parents facing similar challenges.”

Litt encouraged parents to consider the source when obtaining information on social media platforms.

“When in doubt, parents should view social media advice as a starting point for reflection and conversation—not a substitute for consulting trusted professionals,” she said.

An important next step for future research, Litt added, is translating these findings into practical, parent-facing interventions.

“The goal of our current research,” Litt said, “is to create freely accessible resources that retain what parents value about social media, such as immediacy, relatability, and grounding in lived experience while ensuring accurate, developmentally appropriate, and evidence-based content.”

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Journal

Journal of Studies on Alcohol and Drugs

DOI

10.15288/jsad.25-00310 

Method of Research

Content analysis

Subject of Research

People

Article Title

Parents Use Online Communities to Seek Guidance on Child Substance Use, Parental Use, and Family Substance Use Challenges: A Content Analysis of Reddit Posts

COI Statement

JPA has received fees for consulting services in court cases pertaining to content on social media platforms. All other authors have no conflicts to disclose.

 

Your future home might be framed with printed plastic

MIT engineers are using recycled plastic to 3D print construction-grade floor trusses.

Massachusetts Institute of Technology

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On left, the MIT HAUS large format 3D printer system deposits the first layer of a polymer composite 3D printed floor truss. A closeup of a notched joint is seen on right, and the assembled floor system undergoing a bending test with a ~2,000lb concrete block load in the center.

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Credit: Courtesy of AJ Perez, et al

The plastic bottle you just tossed in the recycling bin could provide structural support for your future house. 

MIT engineers are using recycled plastic to 3D print construction-grade beams, trusses, and other structural elements that could one day offer lighter, modular, and more sustainable alternatives to traditional wood-based framing. 

In a paper published in the Solid FreeForm Fabrication Symposium Proceedings, the MIT team presents the design for a 3D-printed floor truss system made from recycled plastic. 

A traditional floor truss is made from wood beams that connect via metal plates in a pattern resembling a ladder with diagonal rungs. Set on its edge and combined with other parallel trusses, the resulting structure provides support for flooring material such as plywood that lies over the trusses.  

The MIT team printed four long trusses out of recycled plastic and configured them into a conventional plywood-topped floor frame, then tested the structure’s load-bearing capacity. The printed flooring held over 4,000 pounds, exceeding key building standards set by the U.S. Department of Housing and Urban Development. 

The plastic-printed trusses weigh about 13 pounds each, which is lighter than a comparable wood-based truss, and they can be printed on a large-scale industrial printer in under 13 minutes. In addition to floor trusses, the group is working on printing other elements and combining them into a full frame for a modest-sized home.  

The researchers envision that as global demand for housing eclipses the supply of wood in the coming years, single-use plastics such as water bottles and food containers could get a second life as recycled framing material to alleviate both a global housing crisis and the overwhelming demand for timber.

“We’ve estimated that the world needs about 1 billion new homes by 2050. If we try to make that many homes using wood, we would need to clear-cut the equivalent of the Amazon rainforest three times over,” says AJ Perez, a lecturer in the MIT School of Engineering and research scientist in the MIT Office of Innovation. “The key here is: We recycle dirty plastic into building products for homes that are lighter, more durable, and sustainable.” 

Perez’ co-authors on the study are graduate students Tyler Godfrey, Kenan Sehnawi, Arjun Chandar, and professor of mechanical engineering David Hardt, who are all members of the MIT Laboratory for Manufacturing and Productivity.

Printing dirty

In 2019, Perez and Hardt started MIT HAUS, a group within the Laboratory for Manufacturing and Productivity that aims to produce homes from recycled polymer products, using large-scale additive manufacturing, which encompasses technologies that are capable of producing big structures, layer-by-layer, in relatively short timescales. 

Today, some companies are exploring large-scale additive manufacturing to 3D-print modest-sized homes. These efforts mainly focus on printing with concrete or clay — materials that have had a large negative environmental impact associated with their production. The house structures that have been printed so far are largely walls. The MIT HAUSgroup is among the first to consider printing structural framing elements such as foundation pilings, floor trusses, stair stringers, roof trusses, wall studs, and joists. 

What’s more, they are seeking to do so not with cement, but with recycled “dirty” plastic — plastic that doesn’t have to be cleaned and preprocessed before reuse. The researchers envision that one day, used bottles and food containers could be fed directly into a shredder, pelletized, then fed into a large-scale additive manufacturing machine to become      structural composite construction components. The plastic composite parts would be light enough to transport via pickup truck rather than a traditional lumber-hauling 18-wheeler. At the construction site, the elements could be quickly fitted into a lightweight yet sturdy home frame. 

“We are starting to crack the code on the ability to process and print really dirty plastic,” Perez says. “The questions we’ve been asking are, what is the dirty, unwanted plastic good for, and how do we use the dirty plastic as-is?”

Weight class

The team’s new study is one step toward that overall goal of sustainable, recycled construction. In this work, they developed a design for a printed floor truss made from recycled plastic. They designed the truss with a high stiffness-to-weight ratio, meaning that it should be able to support a given amount of weight with minimal deflection, or bending. (Think of being able to walk across a floor without it sagging between the joists.) 

The researchers first explored a handful of possible truss designs in simulation, and put each design through a simulated load-bearing test. Their modeling showed that one design in particular exhibited the highest stiffness-to-weight ratio and was therefore the most promising pattern to print and physically test. The design is close to the traditional wood-based floor truss pattern resembling a ladder with diagonal, triangular rungs. The team made a slight adjustment to this design, adding small reinforcing elements to each node where a “rung” met the main truss frame. 

To print the design, Perez and his colleagues went to MIT’s Bates Research and Engineering Center, which houses the group’s industrial-scale 3D printer — a room-sized industrial machine that is capable of printing large structures at a fast rate of up to 80 pounds of material per hour. For their preliminary study, the researchers used pellets made of a combination of recycled PET polymers and glass fibers — a mixture that improves the material’s printability and durability. They obtained the material from an aerospace materials company, and then fed the pellets into the printer as composite “ink.” 

The team printed four trusses, each measuring 8 feet long, 1 foot high, and about 1 inch wide. Each truss took about 13 minutes to print. Perez and Godfrey spaced the trusses apart in a parallel configuration similar to traditional wood-based trusses, and screwed them into a sheet of plywood to mimic a 4-x-8-foot floor frame. They placed bags of sand and concrete of increasing weight in the center of the flooring system and measured the amount of deflection that the trusses experienced underneath. 

The trusses easily withstood loads of 300 pounds, well above the deflection standards set by the U.S. by the Department of Housing and Urban Development. They didn’t stop there, continuing to add weight. Only when the loads reached over 4,000 pounds did the trusses finally buckle and crack. 

In terms of stiffness, the printed trusses meet existing building codes in the U.S. To make them ready for wide adoption, Perez says the cost of producing the structures will have to be brought down to compete with the price of wood. The trusses in the new study were printed using recycled plastic, but from a source that he describes as the “crème de la crème of recycled feedstocks.” The plastic is factory-discarded material, but is not quite the “dirty” plastic that he aims ultimately to shred, print, and build. 

The current study demonstrates that it is possible to print structural building elements from recycled plastic. Perez is in the process of working with dirtier plastic such as used soda bottles — that still hold a bit of liquid residue — to see how such contaminants affect the quality of the printed product. 

If dirty plastics can be made into durable housing structures, Perez says “the idea is to bring shipping containers close to where you know you’ll have a lot of plastic, like next to a football stadium. Then you could use off-the-shelf shredding technology and feed that dirty shredded plastic into a large-scale additive manufacturing system, which could exist in micro-factories, just like bottling centers, around the world. You could print the parts for entire buildings that would be light enough to transport on a moped or pickup truck to where homes are most needed.” 

This research was supported, in part, by the Gerstner Foundation, the Chandler Health of the Planet grant, and Cincinnati Incorporated.

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Written by Jennifer Chu, MIT News

Paper: “Design, Manufacture and Testing of Structural Trusses using Additively Manufactured Polymer Composites”

https://utw10945.utweb.utexas.edu/sites/default/files/2025/4%20Design%2C%20Manufacture%20and%20Testing%20of%20Structural%20Tr.pdf

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Article Title

“Design, Manufacture and Testing of Structural Trusses using Additively Manufactured Polymer Composites”

The completed floor system, pictured, shows four piles, two endcaps and four trusses. 

Credit

Courtesy of AJ Perez, et al

 

No fences needed: GPS collars show ‘virtual fencing’ is next frontier of livestock grazing

Mizzou’s Center for Regenerative Agriculture is helping Missouri farmers effortlessly rotate their livestock for optimal cover-crop grazing

University of Missouri-Columbia

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Virtual fencing 

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Credit: University of Missouri

For generations, farmers have spent backbreaking hours tearing down and rebuilding fences just to move livestock to fresh grazing fields. Now, thanks to a groundbreaking project at the University of Missouri’s Center for Regenerative Agriculture, that chore is becoming a thing of the past.

With a $900,000 grant from the National Fish and Wildlife Foundation, five Missouri producers are beta testing a high-tech virtual fencing solution that uses GPS-enabled collars and a simple mobile app to guide animals with sound and mild shock cues. No posts, no wires, no sweat. Just smarter grazing, healthier pastures and more time back in a farmer’s day.

Kaitlyn Dozler, manager of Mizzou’s Virtual Fence Program, is leading the three-year project alongside Rob Myers, a professor with the College of Agriculture, Food and Natural Resources and director of the Mizzou Center for Regenerative Agriculture. The project is specifically designed for Missouri farmers whose animals graze on cover crops — plants that protect and improve soil during the time of year when cash crops are not being grown.

“Farmers might be out multiple times a day moving their physical fences in extreme weather, so using virtual fencing can make their lives so much easier,” Dozler said. “One producer told me she was able to take a vacation for the first time in five years because she knew she could just go online at any time and see exactly where her goats were.”

Four of the five Missouri livestock producers involved in the project — which began last summer — have collared their cattle, while the fifth has collared his sheep. All five producers have enjoyed the convenience of using the new technology so far and, as part of the grant, are sharing their experiences with other Missouri farmers at events such as the 2026 Missouri Cattle Industry Convention and Trade Show.

“Farmers trust other farmers,” Dozler said. “By hearing about the experiences from those who have tried the new technology, it becomes a smoother process for producers wanting to adopt it on their farms.”

Chris Hudson owns a farm in Middletown, Missouri, and collared 50 of his cattle as part of the project. After switching to virtual fencing, he saw much higher utilization of his cover crops, from about 90 grazing days per acre with physical fences to 170 grazing days per acre with virtual fencing. In other words, Hudson got nearly double the value from the same acre of land since the cattle ate all the cover crops in one field before moving on to the next field.

“I also like how the app allows me to see where each individual cow is at all times,” Hudson said. “When I saw on the app that one of my pregnant cows went off by herself, I knew it was time for her to give birth. I was able to call my dad to go check on the new calf without leaving what I was doing at the time, so the convenience is a real benefit.”

Dozler added the best part of using virtual fencing is the peace of mind it provides.

“Say a producer is at their child’s sporting event and they get the dreaded call that cattle are out. Instead of having to leave to go check if it’s their cattle, the producer can just check their phone to ensure the virtual fence is active and see their livestock’s location instantly,” Dozler said. “Giving people the flexibility to spend more time with their family is so rewarding.”

The project symbolizes Mizzou’s mission as a land-grant university.

“The collaboration with Mizzou faculty, MU Extension and the Center for Regenerative Agriculture has helped get innovative technology in the hands of Missouri farmers who can benefit from it,” Dozler said. “While virtual fencing is not meant to be used as a perimeter fence, it can have great benefits as an interior fence for rotational grazing. I want to put Mizzou on the map for this awesome technology and spread the word about what it can do for livestock producers.”