Tuesday, March 07, 2023

 

Novel method developed to stabilize zinc-ion batteries

Peer-Reviewed Publication

HEFEI INSTITUTES OF PHYSICAL SCIENCE, CHINESE ACADEMY OF SCIENCES

Novel Method Developed to Stabilize Zinc-ion Batteries 

IMAGE: THE SCHEMATIC DIAGRAMS FOR ZN DEPOSITION CYCLED IN DIFFERENT ELECTROLYTES. (A) BARE ZNSO4 ELECTROLYTE; (B) DX/ZNSO4 ELECTROLYTE. view more 

CREDIT: LI ZHAOQIAN

According to research published in international journal of ACS Nano recently, a team led by Dr. LI Zhaoqian. from Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Science (CAS) found that the addition of 1,4-dioxane (DX) molecules in the electrolyte of aqueous zinc ion battery would lead to the preferred Zn (002) texture growth, which effectively suppressed the Zn dendrite growth and improved the reversibility and cycling stability of batteries.

Aqueous rechargeable zinc-ion batteries (ZIBs) are an emerging sustainable system for the next generation of grid-scale energy storage technology. However, the implementation of this technology has been plagued by the serious dendrite issue and poor reversibility of Zn anode. In hexagonal close-packed Zn crystal, (002) facet possesses the lowest surface energy and the slowest growth rate rendering a surface-reaction-controlled deposition process, and thus mitigating the rampant Zn2+ flux and side-reactions. Therefore, inducing preferred Zn (002) texture can effectively alleviate the dendrite growth and the formation of side-reactions.

In this study, researchers constructed an advanced electrolyte modulating strategy to adjust the anode/electrolyte interface. In this new system, the adsorption of 1,4-Dioxane (DX) on the Zn surface can induce Zn (002) texture growth and suppress the detrimental side-reactions.

The performance of the new system was validated in later experiments. Battery with the addition of DX demonstrated a long-term cycling stability of 1000 h, even at harsh condition of 10 mA cm-2 with an ultrahigh cumulative plated capacity of 5 Ah cm-2. The battery also showed a high reversibility with average coulombic efficiency of 99.7%.

"The Zn//NH4V4O10 full cell with DX realized high specific capacity and capacity retention," said Dr. LI Zhaoqian, "It's much better than ZIBs with pristine ZnSO4 electrolyte."

This study selectively adjusted the deposition rate of Zn2+ on the crystal plane by adsorbing molecules, which provided a promising strategy for modulating high performance zinc anodes at the molecular level, and was expected to be applied to other metal anodes with poor stability and reversibility.

(a) The in-situ optical microscopic comparison of the deposited Zn anode surface in the ZnSO4 electrolyte and DX/ZnSO4 electrolyte. (b, c) The XRD patterns and SEM images show the (002) texture in the DX/ZnSO4 electrolyte. (d, e) The adsorption energy comparison.

CREDIT

LI Zhaoqian

Astronomers detect radio recombination lines of carbon/oxygen ions for first time

Peer-Reviewed Publication

CHINESE ACADEMY OF SCIENCES HEADQUARTE

First detection of radio recombination lines of carbon/oxygen using TMRT 

IMAGE: THE WHITE LINE SHOWS THE RRLS OF IONS OF C AND/OR O DETECTED BY TMRT. THE GREEN AREAS ARE THE MODELED EMISSION OF ION RRLS. THE GREEN DOTTED LINES ARE THE MODELED EMISSION, TAKING INTO ACCOUNT ALL RLLS AND MOLECULAR LINES. THE BACKGROUND IS THE IMAGE OF THE HEART-SHAPED ORION NEBULA (M42), WITH ORION KL LOCATED WITHIN THE LOWER-LEFT BRIGHT REGION OF M42, CREDIT TO SHAWN NIELSEN. view more 

CREDIT: SHAO

A research team from the Shanghai Astronomical Observatory (SHAO) of the Chinese Academy of Sciences has detected radio recombination lines (RRLs) of ions heavier than helium for the first time, using the TianMa 65-m Radio Telescope (TMRT). These lines were assigned to carbon and/or oxygen ions.

The findings were published in Astronomy & Astrophysics on Feb. 28.

Ionized gas is the most widely distributed interstellar gas component and an important laboratory for measuring the abundance of elements. Radio recombination lines (RRLs) can avoid the difficulties of optical line observations, since RRLs are usually optically thin and have well understood emission mechanisms.

However, detected RRL emitters have nearly all been neutral atoms so far. Only two RRL transitions (121α and 115α) of helium ions in planetary nebulae have been previously reported. Line blending makes the RRLs of atoms heavier than helium difficult to spectrally resolve. In contrast, the RRLs of ions are not generally blended with RRLs of neutral atoms, making the former a much more powerful tool for measuring abundance.

The researchers made this new discovery while searching for interstellar emission lines as part of an ongoing TMRT spectral line survey toward Orion KL. While identifying the Ka-band (26-35 GHz) spectral lines of Orion KL, they found several broad line features that could not be assigned to any molecular species nor to the RRLs of atoms.

"These line features have weak intensities, but are already significant enough to be distinguished due to the high sensitivity of the spectrum. Because their line widths are similar to those of H/He RRLs, we realized that those line features could be RRLs of ions," said Dr. LIU Xunchuan from SHAO, corresponding and first author of the study.

To confirm this, the astronomers conducted follow-up Ku-band (12-18 GHz) observations using TMRT to search for signals of ion RRLs at the expected frequencies, and eight more alpha lines (RRLs with Δn=1) of ions were detected.

In addition, they found marginal signals of alpha lines in the Q band and beta lines (Δn=2) in the Ka band. They compared the spectra obtained on different days and found that the frequencies of the line features remained unchanged when corrected for the motion of the Earth, confirming that the ion RRLs originated from space.

In total, tens of RRLs of interstellar ions were detected by TMRT, and many of them are not blended with any transitions of molecules nor with RRLs of atoms. The lines detected by TMRT are more than 20 kilometers per second bluer than the expected frequencies of helium ion RRLs and were thus assigned to ions heavier than helium. The abundance of the doubly ionized elements associated with those ion RRLs was accurately determined to be 8.8 parts per 10,000, which is consistent with the value of carbon/oxygen estimated from optical/infrared observations.

Previously, RRLs were commonly defined as radio spectral lines, caused by transitions of high-n levels of atoms, that appeared after the recombination of singly ionized ions and electrons. But now, the researchers have detected tens of unblended ion RRLs simultaneously.

"Such a new technique would be very valuable to study the abundances of carbon and oxygen, the most important constituents of carbon monoxide and interstellar complex organic molecules, in the inner Galaxy, where optical observations are very difficult," said Prof. Neal J. Evans II from the University of Texas at Austin.

SHAO researchers see this new discovery by TMRT as the first of many. "The ongoing TMRT spectral line survey towards Orion KL and other Galactic objects will reach an unprecedented line sensitivity, which will lead to more new discoveries such as RRLs of heavy ions, new transitions of molecular lines and even new molecule species," said LIU Tie, a researcher in SHAO and co-corresponding author of the study.

A warmer world will make heatwaves more frequent: Study

Peer-Reviewed Publication

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

From late June to early July 2021, an unprecedented heatwave swept across Western North America (WNA), causing considerable hazards to the regional society and economy. What is the likelihood of a similar heatwave under global warming?

Researchers led by Prof. Lin Wang from the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences, in collaboration with scientists from Yunnan University, have revealed that heatwaves similar to the unprecedented WNA one in summer 2021 are projected to become more frequent in a warmer world based on the multi-model simulations from the Coupled Model Intercomparison Project. The project began in 1995 under the auspices of the World Climate Research Programme (WCRP) and is now in its sixth phase (CMIP6).

The study was published in Earth's Future .

"Such a heatwave is projected to occur more frequently with increased extreme temperature and shortened return period, making a rare event in the current climate be a common event in a warmer climate," said Prof. Wang, corresponding author of the study, "especially under a high-emission scenario like the Shared Socioeconomic Pathways 585 (SSP5-8.5)."

Moreover, the researchers found a large expansion of areas over WNA that will break the 2021 record in the future with an increasing level of emission scenario. However, some heat records west of the Rocky Mountains are still difficult to break even at the end of the 21st century, highlighting the specific extremity of the observed 2021 WNA heatwave.

"We use multiple climate models that are involved in CMIP6 and consider different emission scenarios and warming levels for the future heatwave projections over WNA," said Dr. Zizhen Dong, first author of the study.

Drones detect moss beds and changes to Antarctica climate

Queensland University of Technology

Peer-Reviewed Publication

QUEENSLAND UNIVERSITY OF TECHNOLOGY

QUT drones detect moss beds and climate changes in Antarctica 2023 summer 

IMAGE: QUT DRONE VISION OF AUSTRALIAN SPECIALLY PROTECTED AREAS IN ANTARCTICA CURRENTLY BEING STUDIED TO CLASSIFY CHANGES IN THE EXTREME ENVIRONMENT. view more 

CREDIT: CREDIT: QUT

Researchers have been using drones to map large areas of Antarctica this summer in efforts to monitor the effects on vegetation due to climate change with the support of the Federal Government’s Australian Antarctic Division.

The drone-derived imagery is being used by researchers from QUT and Auckland University of Technology – with assistance from University of Wollongong - to evaluate the fragile ecosystem, particularly moss beds, and changes in the extreme environment.

For almost two months, the field team was based in Antarctica, with indications the drones they piloted captured unprecedented high-resolution imagery of vegetation and biodiversity in protected areas.

The vision taken from Australian Specially Protected Areas (ASPAs 135 and 136), not far from the scientists’ base settlement of Casey Station, identified areas with moss and lichen not previously picked up by satellite.

QUT Centre for Robotics researcher Dr Juan Sandino, who specialises in mechatronics and automated remote sensing systems, helped develop and deploy the drones, classifying Antarctic vegetation at low altitude.

“Piloting these flights was at times challenging; however all the systems performed well under extreme cold conditions,” he said.

He said working in Antarctica demanded rigorous physical preparation and had additional logistical pressure of ensuring the heavy equipment was operational.

The seven-year $3.57 million project is co-led by QUT Professor Felipe Gonzalez and Auckland University of Technology Professor Barbara Bollard.

The project’s key aims included monitoring the vegetation through smart sensors and artificial intelligence, modelling microclimates, and producing accurate maps of protected areas and other ice-free regions.

“Few plants can survive in Antarctica and mosses are the largest and oldest plants to grow there with beds up to 50 metres wide and plants as old as 500 years,” Professor Bollard said.

“The moss is sensitive to variations of temperature and moisture in Antarctica and is an important indicator of climate change.”

Professor Gonzalez said mapping and monitoring the moss beds over time will help to understand the health of mosses and other vegetation.

The research is conducted as part of Securing Antarctica’s Environmental Future (SAEF), a $36 million research program funded by the Australian Research Council as a special research initiative.

Further drone-derived imagery as well as AI for other Antarctic regions may be used to evaluate the effectiveness of area-based conservation interventions in more parts of the icy continent.

QUT research, published recently in Conservation Biology, presented a case and a research agenda evaluating the conservation impact of Antarctica’s protected areas.

PhD researcher Joanna Burrows and supervisor Professor Kerrie Wilson, who are also part of SAEF, identified a gap in the research regarding the effectiveness of Antarctic Specially Protected Areas (ASPAs).

Ms Burrows said that drones can provide new and more detailed information to evaluate the performance of ASPAs.

“Drones could increase the likelihood of successful data collection by allowing remote and fragile ecosystems to be surveyed with low impact and can mitigate some accessibility issues,” Ms Burrows said.

QUT's Dr Juan Sandino helped develop and deploy the drones to classify Antarctic vegetation at low altitude.

CREDIT

Credit: QUT Media

QUT piloted drones detect moss [VIDEO] |


B roll Antarctica of QUT drone [VIDEO] | 

Ethnic minority parents want customized advice, research shows


Researchers interviewed parents from minority regions of Inner Mongolia and examined their preferences and needs concerning guidance on child-rearing. Their findings suggest parents want more specific knowledge on family education in Inner Mongolia.


Peer-Reviewed Publication

XI'AN JIAOTONG-LIVERPOOL UNIVERSITY

Inner Mongolian children taking part in an Eagle Dance 

IMAGE: INNER MONGOLIAN CHILDREN TAKING PART IN AN EAGLE DANCE - SEEN AT THE 17TH NAADAM FAIR ON GEGENTALA STEPPE IN INNER MONGOLIA NEAR BAOTOU view more 

CREDIT: CHEMOPHILIC

Over the last decade, parents have become increasingly aware of the importance of a child's physical and mental development in the early years. As a result, there has been a significant rise in parents' demand for evidence-based knowledge of child-rearing.

However, few studies have focused on the needs and preferences of ethnic minority groups when it comes to family education programmes.

In a recent study published in the International Journal of Environmental Research and Public Health, researchers from China and the Czech Republic interviewed 24 parents from minority regions of Inner Mongolia and examined their preferences and needs concerning guidance on child-rearing. 

Dr Jinjin Lu from Xi'an Jiaotong-Liverpool University in China, and corresponding author of the study, says: "During the interviews, many parents mentioned that Inner Mongolia's unique location and rich natural resources had drawn their attention to how the environmental factors could influence children's growth.

"The parents were curious to know, for example, whether the geomagnetic field could influence a child's physical and mental well-being. 

"It seemed that the parents were eager for more specific knowledge on family education in Inner Mongolia."

Evidence-based family education

Apart from the influence of geographical features, the parents from Inner Mongolia were also concerned with issues including children's health, their acquisition of soft skills, and how they could make a smooth transition from kindergarten to primary school. 

After the Law of the People's Republic of China on the Promotion of Family Education was implemented in 2021, parents, community workers, and early childhood teachers have worked harder to create evidence-based early childhood programmes, as much of the existing advice and information on child-rearing in China is based on Chinese cultural norms and family traditions.

To ensure evidence-based programmes are as effective as possible, it has become necessary to understand parents' preferences and needs concerning parental knowledge and family education.

Dr Lu says: "Despite their access to a wide range of information sources, the parents we spoke to from minority regions of Inner Mongolia wanted more guidance on evidence-based parenting programmes. 

"Theoretical parenting advice can often be boring and obscure, so parents say they would prefer easy-to-understand guidance supported by data."

Recognising specific needs

When asked why parents from Inner Mongolia were chosen for the study, Dr Lu explains: "China is a multi-ethnic country, but most existing studies focus solely on Han Chinese families. It is, therefore, a relatively new practice to study the parenting styles and family education programmes of other ethnic groups."

According to Dr Lu, most participants were eager to acquire knowledge and skills that could help them facilitate their children's growth with evidence-based information.

"The results of the study suggest that policymakers and teachers should be fully aware of the local situations when designing or intervening in family education programmes. 

"They should also have a thorough knowledge of the local culture and the parents' needs before offering specific advice on child-rearing." 

Dr Lu also called for more scholars to pay attention to family education in disadvantaged or underdeveloped areas in the future.

A mixture of trees purifies urban air best

Peer-Reviewed Publication

UNIVERSITY OF GOTHENBURG

Measuring clorophyll 

IMAGE: MEASUREMENT OF CHLOROPHYLL IN LEAVES USING A CHLOROPHYLL MEASUREMENT DEVICE CALLED A SPAD. THE MEASUREMENT IS DONE USING LIGHT, LEAVING THE LEAF UNDAMAGED. view more 

CREDIT: JENNY KLINGBERG

Conifers are generally better than broadleaved trees at purifying air from pollutants. But deciduous tree may be better at capturing particle-bound pollution. A new study led by the University of Gothenburg shows that the best trees for air purification depend on the type of pollutant involved.

Trees and other greenery in cities provide many benefits that are important for the well-being of residents. Leaves and needles on trees filter air pollutants and reduce exposure to hazardous substances in the air. But which trees purify the air most effectively? Researchers from the University of Gothenburg have collected leaves and needles from eleven different trees growing in the same place in the Gothenburg Botanical Garden’s arboretum (tree collection) to analyse which substances they have captured.

“This tree collection provides a unique opportunity to test many different tree-species with similar environmental conditions and exposure to air pollutants,” says Jenny Klingberg, a researcher at the Gothenburg Botanical Garden.

Harmful pollutants

A total of 32 different pollutants were analysed, some of which are bound to particles of various sizes. Others are gaseous. There is a proven connection between exposure to air pollutants and increased risk of cardiovascular diseases and airway problems. This project has focused on polycyclic aromatic hydrocarbons (PAHs). In cities, traffic is the biggest source of these pollutants, which are released due to incomplete combustion in engines.

“Our analyses show that different tree species have different abilities to absorb air pollutants. Conifers generally absorbed more gaseous PAHs than broadleaved trees. Another advantage of conifers is that they also act as air purifiers in winter, when air pollution is usually at its highest,” says Jenny Klingberg.

Needles clean air for many years

The researchers also saw that needles continued to absorb air pollutants for several years, which leaves cannot do for obvious reasons. But broadleaved trees had other advantages. They were more efficient at cleaning the air of particles, which is thought to be due to the leaves having a larger surface area to which particles can attach.

“The various species differed more than we expected. Larch, which is a conifer that sheds its needles each autumn, was best in test. Larch trees absorbed the most particle-bound pollutants, but were also good at capturing gaseous PAHs,” says Jenny Klingberg.

Needles and leaves do not, however, break down pollutants to any greater extent, even if sunlight can start that process. Thus there is a risk that the soil beneath the trees will be contaminated by pollutants when the leaves and needles shed and decompose. This places the ecosystem in the soil at risk of being affected, though this has not been investigated in the current study being published in the journal Ecological Indicators.

“The pollutants do not appear to impact the trees’ photosynthesis; leaf chlorophyll content is just as high in the most polluted areas of Gothenburg compared with trees that grow in less polluted environments. But this likely looks different in cities with even worse air quality,” says project leader Håkan Pleijel, professor of applied environmental science at the University of Gothenburg.

Careful urban planning is needed

However, you should not simply start filling city streets with trees to improve air quality for residents. Several factors determine the benefit. An alley of trees in a narrow street canyon can reduce air flow, negatively affecting dispersion and dilution of the air pollutants and therefore increase concentrations of contaminants locally on busy streets. This means that on narrow streets sheltered from wind, lower-growing vegetation, like hedges, may be preferable. Careful urban planning is necessary, combining different tree species to optimise air purification and to take into account other functions and benefits of trees, according to the researchers.

“This study contributes to improving our understanding of the ability of trees to clean the air and which species are best at absorbing air pollutants,” says Håkan Pleijel. This knowledge is important for urban planning when designing sustainable cities. While trees and greenery can contribute to better air quality in cities, at the end of the day the most important measure is to reduce emissions.


Uptake of hydrocarbon in different tree-species

CREDIT

Håkan Pleijel


JOURNAL

Community strategy reduced opioid overdose deaths in Pennsylvania counties

Peer-Reviewed Publication

UNIVERSITY OF PITTSBURGH

Janice Pringle, Ph.D. 

IMAGE: JANICE PRINGLE, PH.D., PROFESSOR OF PHARMACY AND THERAPEUTICS AND DIRECTOR OF THE PROGRAM EVALUATION AND RESEARCH UNIT (PERU) AT THE UNIVERSITY OF PITTSBURGH SCHOOL OF PHARMACY. view more 

CREDIT: JAN SHAW, UNIVERSITY OF PITTSBURGH

PITTSBURGH, March 6, 2023 — The monthly opioid overdose death (ODD) rate fell by 30% in Pennsylvania counties that implemented a novel community-focused strategy developed by University of Pittsburgh researchers, according to a new study published today in the Journal of Studies on Alcohol and Drugs.

By analyzing counties that did or didn’t implement the Pennsylvania Opioid Overdose Reduction Technical Assistance Center (ORTAC) strategy over time, the researchers estimate that this cost-effective, community-led approach prevented 1,818 opioid-related deaths over two years.

“I passionately believe that communities have to come together and be empowered to take control of their own public health to really make sea change on issues like ODD,” said senior author Janice Pringle, Ph.D., professor of pharmacy and therapeutics and director of the Program Evaluation and Research Unit (PERU) at the Pitt School of Pharmacy. “Our study is one of the first to show that a community approach is how you move the needle on preventing ODD.”

According to Pringle, public health issues such as the opioid crisis are usually tackled through dozens of disconnected initiatives led by organizations or systems that target specific populations. But this kind of approach can lead to certain groups of people falling through the cracks and perpetuating disparities in who is accessing care.

“ORTAC aims to bring efforts together, pool resources and integrate services to reduce opioid-related overdose deaths at a community level,” said Pringle. “If the opioid crisis is a tree, one thousand steak knives is not going to chop it down. We need sixty-seven hands — one for each county in Pennsylvania — on the chainsaw.”

Pringle and her team developed a systematic eight-step framework to build and support community coalitions and help them plan, implement and sustain efforts to decrease opioid supply and demand and reduce the risk of opioid overdose in their counties.

The first step involves gathering leadership from multiple sectors — including first responders, emergency departments, the drug and alcohol system, the mental health system and criminal justice — who have a shared goal of addressing the opioid crisis.

“The idea behind ORTAC is that community members and people on the front lines know what’s best for their community,” said lead author Renee Cloutier, Ph.D., research scientist in the Pitt School of Pharmacy’s Department of Pharmacy and Therapeutics and scientific director of PERU. “The ORTAC team worked to develop and activate community coalitions to clarify the problems in their community, generate plans and act on them.”

After assessing local data to understand overdose deaths and identify their community’s unique needs, coalitions developed and enacted a strategic plan to reduce opioid deaths. Interventions included improving access to treatment programs, educating first responders in leave-behind practices for the opioid-reversing drug naloxone, implementing harm reduction strategies such as syringe service programs and drug disposal services, and developing messaging campaigns aimed at reducing stigma.

To understand the impact of ORTAC, the researchers used data from OverdoseFreePA to analyze ODDs from 2016 to 2019 in 29 counties where ORTAC was implemented and 19 comparison counties. While 67% of ORTAC counties had a reduction in ODD per 100,000 people, just 47% of the comparison counties had a reduction over the same period.

After accounting for factors that could affect opioid deaths, such as county distribution of naloxone beyond ORTAC efforts, illicit drug supply and opioid prescriptions, the researchers found that the ODD rate in ORTAC counties was consistently lower than comparison counties over time, a difference ranging from 1.5 to 3.8 deaths per 100,000 people in the first two years following ORTAC implementation.

“If you fund communities and provide structured support, you can make transformational change beyond what might be possible with a top-down approach,” said Cloutier. “We hope to see more funding targeted toward supporting communities on the ground in this way.”

The researchers calculated that it cost less than $6,000 to prevent each overdose death. For comparison, another analysis estimated the savings associated with avoiding a single ODD at $10.5 million.

“Our strategy had a meaningful impact on reducing ODD and is incredibly cost-effective,” said Pringle. “With more funding and support, we can continue to guide communities to reduce the risk of ODD for everyone because this issue is in all our backyards. The opioid crisis affects us all, and there is so much more work to be done.”

Other authors of the study were Arnie Aldridge, Ph.D., and William Dowd, B.A., both of RTI International; and Glenn Hoffman, B.A., B.S., Kristina L. Boyd, M.S., Erh-Hsuan Wang, Ph.D., Kiandra Foster, M.S., and Karley Snyder, M.S., all of Pitt.

This study was funded by the Pennsylvania Commission on Crime and Delinquency.

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Physician workforce planning must adjust for aging population, changing practice patterns: New analysis

Peer-Reviewed Publication

CANADIAN MEDICAL ASSOCIATION JOURNAL

Why are Canadians having problems accessing physicians despite historic highs in physician numbers? Factoring in changing demographics and physician work trends can help with physician workforce planning, according to a new analysis in CMAJ (Canadian Medical Association Journal) https://www.cmaj.ca/lookup/doi/10.1503/cmaj.221239.

"[T]he increasing [health care] needs of an aging population have been empirically important since around 2005, while the supply of physician service hours has simultaneously declined in a manner that is largely unrelated to the evolving age–sex composition of the physician workforce," writes Dr. Arthur Sweetman, Department of Economics, McMaster University, Hamilton, Ontario, with coauthors. "Thus, relying on simple trends in physicians-per-capita ratios for workforce planning is misleading and not helpful."

The authors hope their analysis will inform governments and the medical profession in planning the appropriate number of new physicians who should enter medical practice.

The analysis looked at trends in the number of physicians and hours of work, and factored in the needs of an aging population between 1987 and 2020. Physician hours of work, while being higher than in most other occupations, declined by 20.6%, from an average of 54.3 hours per week in 1987 to 43.1 hours per week in 2020.

"Despite working more than other occupations, physicians have faced mounting challenges meeting patient needs," says coauthor Dr. Boris Kralj, a professor of economics at McMaster University. "The 1980s physician workload proved unsustainable. In 1987, the average physician worked almost 13 and a half hours per week more than the average Canadian worker, whereas in 2020 that gap had declined to about 6.2 additional hours per week."

Simple adjustments for population aging and physicians' declining hours of work change the apparent 35% increase in physicians per capita between 1987 and 2019 into a 4% reduction.

"The current physician practice environment is not one of resource abundance as suggested by high physician counts, but rather a period of physician shortages like that in the late 1990s. In fact, we are below levels observed in 1987," says Dr. Kralj. "The majority of the increase in physician supply over the past 3 decades has been offset by the rising needs of an aging population."

The analysis also debunks the theory that larger numbers of physicians who identify as working fewer average hours is a substantial contributor to the shortages.

"Females had lower average hours, but that average was relatively stable from 1987 to 2020," write the authors. "In contrast, the hours of male physicians declined, and the gender gap in hours diminished across the period."      

They suggest several potential reasons for the decline in working hours beyond the modest contribution from a larger proportion of older and female physicians in the workforce. Other often-discussed issues, such as physician burnout combined with a desire for an improved work–nonwork balance, must also be at play.

"Our analysis shows that measures of physicians per capita need to be complemented with both demand- and supply-side adjustments to inform planning for health human resources in medicine."

The authors suggest caution in interpreting 2020 numbers as that was the start of the COVID-19 pandemic, and they were unable to evaluate trends for the later part of the pandemic owing to data limitations.