Curbing coronavirus spread in enclosed spaces means better masks, adequate ventilation

Findings show leakage of airborne droplets escaping from masks even when just breathing

AMERICAN INSTITUTE OF PHYSICS

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IMAGE: ILLUSTRATION SHOWS THE REACH OF BREATH WITHOUT A MASK AND DURING VARIOUS MASK AND FACE SHIELD EVALUATIONS. view more 

CREDIT: VENUGOPAL ARUMURU/INDIAN INSTITUTE OF TECHNOLOGY BHUBANESWAR

WASHINGTON, April 6, 2021 -- With research increasingly showing the COVID-19 virus is transmissible via smaller droplets suspended in air, there is a growing concern current public health guidelines of mask wearing and social distancing are insufficient in combating its spread in indoor environments, like prisons, hospitals, and meatpacking plants, where people tend to be in close quarters.

Most research has focused on coughing and sneezing. But studies on how simply breathing might contribute to airborne spread of the virus are rare.

In AIP Advances, by AIP Publishing, researchers at the Indian Institute of Technology Bhubaneswar show social distancing is equally important as mask wearing when people indoors are just breathing or participating in normal conversation, even when there is no risk of coughing or sneezing. They also found mask leakage in the same scenario presents a notable challenge in preventing the virus's spread.

"Our findings show the need for good ventilation systems that take into account the 5 to 10% of aerosolized particle leakage that occurs in each breathing cycle as a way to reduce droplet concentration in enclosed spaces," author Venugopal Arumuru said. "There also is a need for mask design innovation to reduce side and bottom droplet leakage while providing adequate face comfort."

In an experimental setup, a mechanical breathing simulator was connected to a mannequin standing at 5 feet 8 inches tall to simulate regular breath and slightly longer breath typical of healthy adults standing still or involved in moderate activity, like walking, talking, or participating in assembly work. The researchers evaluated the efficacy of various mask types, mask-shield combinations, and only face shield use.

A fog generator was filled with a mixture of water and glycerin to emulate the consistency of saliva droplets in the diameter range of 1-10 micrometers to reflect airborne transmissibility. Droplet exposure was illuminated and captured by video camera.

The researchers found that with no face covering, droplets from breathing can travel up to 4 feet in five seconds. A commercial five-layered mask was found to provide the best protection, with full front-of-face protection and minimal leakage below the chin. A commercial N-95 mask impedes droplet leakage in front, but leakage in gaps between the mask and nose was significant.

Leakage from the front of the surgical mask was evident, although adding a face shield increased droplet restriction.

"However, the noticeable droplets settling below the shield is concerning, and pairing surgical masks with shields is not adequate in hospitals and other places where strict social distancing guidelines are difficult to follow," Arumuru said.

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The article "Breathing, virus transmission and social distancing - An experimental visualization study" is authored by Venugopal Arumuru, Jangyadatta Pasa, Sidhartha Sankar Samantaray, and Vaibhavsingh Surendrasingh Varma. The article will appear in AIP Advances on April 6, 2021 (DOI: 10.1063/5.0045582). After that date, it can be accessed at https://aip.scitation.org/doi/10.1063/5.0045582.

ABOUT THE JOURNAL

AIP Advances is an open access journal publishing in all areas of physical sciences--applied, theoretical, and experimental. The inclusive scope of AIP Advances makes it an essential outlet for scientists across the physical sciences. See https://aip.scitation.org/journal/adv.

 

What can we learn from vanishing wildlife species: The case of the Pyrenean Ibex

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IMAGE: LAÑA, THE LAST SURVIVING PYRENEAN IBEX, RETURNED AS A MOUNTED ANIMAL TO TORLA-ORDESA ON THE 6TH NOVEMBER 2012 AFTER ITS CONTROVERSIAL CLONING ATTEMPT. HER SKIN IS NOW EXHIBITED IN THE... view more 

CREDIT: MANOLO GRASA

Likely the first extinction event of the 2000s in Europe, the sad history of the Pyrenean Ibex (Capra pyrenaica pyrenaica) is a powerful example of the ever-increasing species loss worldwide due to causes related to human activity. It can, however, give us valuable information on what should be done (or avoided) to halt this extinction vortex.

The distribution of this subspecies of Iberian Ibex was limited to the French and Spanish Pyrenees. Its first mention in an official written document, dating back to 1767, already refers to it as extremely rare. Like many other mountain goats, it was almost hunted to extinction before its killing became prohibited in 1913. Neither the institution of a national park (Ordesa & Monte Perdido), nor a conservation project with European LIFE program funding could stop the extinction of the Pyrenean Ibex eventually officialised on January 6, 2000. But the story of this charismatic animal did not end there - a controversial cloning program was started instantly with no scientific agreement, nor support from regional environmental NGOs, claiming that de-extinction was possible even in the absence of further DNA studies.

To find out more about the drivers of its extinction, an international team composed of 7 nationalities built a database of all known museum specimens and reconstructed the demographic history of the Pyrenean Ibex based on DNA evidence. Their research is published in the open-access, peer-reviewed journal Zoosystematics and Evolution.

The research found that after a population expansion between 14,000 and 29,000 years ago (which is quite recent from a genetic point of view), a significant loss of genetic diversity followed between approximately 15,000 and 7,500 years BP, and continued until present. By that time, the Pyrenean Ibex also lived outside the Pyrenean mountain chain, but, gradually, its distribution was reduced to only one valley in the Ordesa National Park in the Spanish Pyrenees.

Written sources confirm hunting of the Pyrenean Ibex from as early as the 14th century, and during the 19th and 20th century it became a common target for trophy hunters. Undoubtedly, hunting played an important role in reducing its population numbers and distribution area, but it is not possible - with the information currently available - to pinpoint it as the straw that broke the camel's back. Infectious diseases that originate from livestock (for instance, those caused by the bluetongue virus, BTV, and sarcopses) are capable of decimating other subspecies of Iberian Ibex in extremely short periods of time.

While the relative contribution of various factors remains largely unknown, it seems that hunting and diseases transmitted from other animals have been effective in drastically reducing the number of Pyrenean ibexes over the last two centuries, because they were acting on an already genetically weakened population. This low genetic diversity, combined with inbreeding depression and reduced fertility, brought the population beyond the minimum viable size - from that point onwards, extinction was inevitable.

This case study shows the importance of historical biological collections for genetic analyses of extinct species. A privately owned 140-year-old trophy preserved in Pau, France, was genotyped as part of this research, showing that private individuals may possess material of high value. As there is little knowledge of such resources, the authors call for the creation of an online public database of private collections hosting biological material for the benefit of biodiversity studies.

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Original source:

Forcina G, Woutersen K, Sánchez-Ramírez S, Angelone S, Crampe JP, Pérez JM, Fandos P, Granados JE, Jowers MJ (2021) Demography reveals populational expansion of a recently extinct Iberian ungulate. Zoosystematics and Evolution 97(1): 211-221. https://doi.org/10.3897/zse.97.61854

CAPTION

The adventures of the British hunter E.N. Buxton were published in 1893. This engraving represents a hunting party in the Ordesa Valley (Spanish Pyrenees).

CAPTION

Only the French mountaineer and photographer Bernhard Clos managed to take a series of good photos of the Bucardo, as the Pyrenean Ibex is called on the Spanish side.

CREDIT

Bernhard Clos

 

COVID-19 pandemic threatens to reverse gains made on Sustainable Development Goal 1 and 2

Researchers studying the impact of COVID-19 restrictions on food production among smallholder bean farmers in 11 countries found multiple food security threats

THE ALLIANCE OF BIOVERSITY INTERNATIONAL AND THE INTERNATIONAL CENTER FOR TROPICAL AGRICULTURE

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IMAGE: BORDER CONTROLS AND HIGH TRANSPORT COSTS HAVE LED TO DROPS IN PRODUCTION OF THE KEY FOOD SECURITY CROP IN SUB-SAHARAN AFRICA. view more 

CREDIT: GEORGINA SMITH

A new study analyzing bean production and food security across 11 countries in sub-Saharan Africa, found COVID-19 pandemic-related restrictions to significantly impact bean production. Border controls and high transport costs have led to drops in production of the key food security crop, threatening to reverse gains made in achieving Sustainable Development Goals 1 and 2, towards no poverty and zero hunger, respectively.

Even before the pandemic, 55% of the world's hungry people and 70% of the world's poorest people lived in Africa, the researchers said. In addition, food systems across Africa were already affected by the adverse impacts of climate change, disease and pests, such as the worst desert locust outbreak in 70 years impacting food security in Kenya, Somalia, Ethiopia and other countries in eastern Africa.

Other impacts of COVID-19 restrictions, both direct and indirect, can be found in the study: "Regional impact of COVID-19 on the production and food security of common bean smallholder farmers in Sub-Saharan Africa: Implication for SDG's," published in the Global Food Security edition of peer-reviewed platform Science Direct. Direct impacts include farms and food businesses closing down; while indirect impacts are linked to lockdown, border closures, social distancing, and restricted transportation and trade.

"The food system is already highly inefficient. What we've seen is that measures taken to control the virus led to wider food security restrictions and disruptions, exacerbating those already-existing insecurities," said author Eileen Nchanji, a gender researcher at The Alliance of Bioversity International and the International Center for Tropical Agriculture (The Alliance). "Pay cuts, job losses, and high food prices due to reduced food imports and closure of informal markets all disrupted food supplies, with poorer communities especially affected."

From border closures to national lockdowns, delayed cargo further exacerbated food shortages, the researchers said. For instance, 15% of imported food in Kenya before the pandemic was sourced from countries that imposed export restrictions, affecting the availability and flow of crops and food. Restrictions also led to limited access to seed, farm inputs, hired labor, and agricultural finance for smallholder farmers, especially those in Uganda, where planting was beginning.

The data, collected between March and April 2020, shows that most households in Eastern Africa ate only twice during the pandemic. Uganda was most affected, with all surveyed farmers eating only once per day during the pandemic. The research also found a 34% decrease in access to labor attributed to the fear of getting the disease, the high cost of public transportation, and social distancing measures. Farmers also noted difficulties in accessing finance, farm inputs, seed and extension information.

The research highlights that 36%, 20%, and 3% of farmers in Burundi, Uganda, and Kenya respectively lost income during the pandemic, with knock-on impacts on food security. The low number in Kenya is due to the fact that crops were already planted, and farmers were relying on maize and other crops stored from the previous harvest for food and to generate income, while in Uganda and Burundi, planting was ongoing, and so more money was spent on inputs, seed and food, as prices and costs of transport increased.

In West Africa, challenges included insecurity, political instability, social conflicts, and climate change, the report said, citing Food and Agriculture projections that 17 million people in the region will face severe food insecurity following measures to contain the virus.

Although governments across the continent have responded by offering economic stimulus packages, much needs to be done to enable the sub-sector to recover from ruins caused by the pandemic, authors said.

Cosmas Lutomia, at the Kenya Agriculture and Livestock Research Organization (KALRO), said: "The pandemic has necessitated a much needed discussion around the complexity of our food systems. We can only achieve sustainable and resilient food systems through strengthening public-private partnerships. We implore governments across the region to strengthen the food systems' resilience to present and future shocks."

The authors called for an immediate transformation of food systems in all the sub-regions. Governments should invest directly in input supply systems and short food supply chains through digital access, mobile-based payments, credit and food delivery, they added.

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Droughts longer, rainfall more erratic over the last 50 years in most of the West

US DEPARTMENT OF AGRICULTURE - AGRICULTURAL RESEARCH SERVICE

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IMAGE: THE TIME BETWEEN RAINFALLS HAS BECOME LONGER AND THE RAINS OCCURRED MORE ERRATICALLY IN THE WESTERN U.S. DURING THE LAST 50 YEARS. view more 

CREDIT: JOEL BIEDERMAN, AGRICULTURAL RESEARCH SERVICE

TUCSON, Ariz., April 6, 2021 - Dry periods between rainstorms have become longer and annual rainfall has become more erratic across most of the western United States during the past 50 years, according to a new study published by the U.S. Department of Agriculture's Agricultural Research Service and the University of Arizona

Against the backdrop of steadily warming temperatures and decreasing total yearly rainfall, rain has been falling in fewer and sometimes larger storms, with longer dry intervals between. Total yearly rainfall has decreased by an average of 0.4 inches over the last half century, while the longest dry period in each year increased from 20 to 32 days across the West, explained co-senior author Joel Biederman, a research hydrologist with the ARS Southwest Watershed Research Center in Tucson, Arizona.

"The greatest changes in drought length have taken place in the desert Southwest. The average dry period between storms in the 1970s was about 30 days; now that has grown to 45 days," Biederman said.

Extreme droughts are also occurring more often in the majority of the West according to historical weather data as there has been an increase in the year-to-year variation of both total rainfall amounts and the duration of dry periods.

Biederman emphasized the growing fluctuations in drought and rain patterns as the most significant change.

"Consistency of rainfall, or the lack of it, is often more important than the total amount of rain when it comes to forage continuing to grow for livestock and wildlife, for dryland farmers to produce crops, and for the mitigation of wildfire risks," Biederman said.

The rate of increasing variability of rainfall within each year and between years also appears to be accelerating, with greater portions of the West showing longer drought intervals since 2000 compared to previous years.

Notable exceptions to these drought patterns were seen in Washington, Oregon and Idaho and the Northern Plains region of Montana, Wyoming, and the most western parts of North and South Dakota. In these regions, the researchers found some increases in total annual rainfall and decreases in drought intervals. Together, these changes support what models have predicted as a consequence of climate change: a northward shift in the mid-latitude jet stream, which brings moisture from the Pacific Ocean to the western United States, according to Biederman.

A critical aspect of this study is the use of actual rainfall data from 337 weather stations spread across the western United States. Biederman contrasted this with the more common use of "gridded" data, which relies on interpolations between reporting stations and tends to smooth out some of the variability revealed by this work.

"Fangyue Zhang, lead author of the manuscript and a post-doctoral researcher on our team, did the hard, painstaking work of compiling and analyzing data from more than 300 weather stations with complete daily records to reveal these changing drought and rainfall patterns," Biederman said.

"We were surprised to find widespread changes in precipitation have already occurred across large regions of the West. For regions such as the desert Southwest, where changes clearly indicate a trend towards longer, more erratic droughts, research is urgently needed to help mitigate detrimental impacts on ecosystem carbon uptake, forage availability, wildfire activity, and water availability for people," said co-senior author William K. Smith, assistant professor, University of Arizona.

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This research was published in Geophysical Research Letters. [https://doi.org/10.1029/2020GL092293]

The Agricultural Research Service is the U.S. Department of Agriculture's chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $17 of economi

 

Persisting endangered status of Serianthes nelsonii reveals need for adaptive management

University of Guam review finds conservation projects have lacked publishable results

UNIVERSITY OF GUAM

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IMAGE: NEWLY EMERGING SERIANTHES NELSONII SEEDLINGS ARE MARKED BY CAMERON MUSSER IN THE DEEP SHADE OF GUAM'S KARST FOREST HABITAT. MUSSER IS AMONG THE CO-AUTHORS OF A SYSTEMATIC REVIEW OF ADAPTIVE... view more 

CREDIT: UNIVERSITY OF GUAM

A University of Guam review of published research on the critically endangered Serianthes nelsonii tree has revealed a reason why the population of the trees continues to be endangered despite a long history of funded conservation projects and a national recovery plan implemented 26 years ago. The review article, co-authored by biologists of the Plant Physiology Laboratory of UOG's Western Pacific Tropical Research Center, was published on March 2 in Horticulturae journal (doi:10.3390/horticulturae7030043).

"A main message of our paper is that decision-makers from funding agencies limit conservation success when practitioners with no demonstrable publication history are funded," said co-author Benjamin Deloso. "This is essentially what happened for decades with the Serianthes nelsonii funding."

Lack of appreciable research to inform management decisions

With a global natural population of less than 50 mature trees and an endemic range of only two small tropical islands in the Mariana Islands, the extinction risks for the Serianthes nelsonii are acute.

The article references a national recovery plan for the tree, published in 1994, that explicitly called for research to increase relevant knowledge. Then no publishable research was generated for the first 21 years of the recovery plan's implementation.

"Critically endangered plant species with extremely small populations are among the most difficult species to study," said co-author April Cascasan. "Researchers must rely on limited numbers of replications and non-destructive experimental approaches to do the best they can to answer urgent research questions."

The authors say the Serianthes nelsonii case study demonstrates the importance of adaptive management. Management decisions in any discipline need to be informed by relevant knowledge. But when an endangered species has not received appreciable historical research, that knowledge does not exist. In these situations, reducing extinction risk requires that conservation programs adapt to a learn-as-you-go approach.

"In other words, there is no species-specific playbook in the beginning," Deloso said. "Practitioners need to write the playbook as the status of knowledge can be recalibrated with each successive grant or contract."

These realities are at the root of why international conservation experts advocate for inclusion of published research scientists in funded conservation projects. When this is done, implementation of the conservation measures will include experimental and observational approaches that generate new knowledge to improve subsequent decisions.

Much learned in a short amount of time

In an effort to fast-track knowledge of the tree's extinction risks and inform conservation protocols, the Plant Physiology Laboratory at the University of Guam has generated a flurry of publications in the past five years.

Additionally, their systematic review of prior research has illuminated the urgency of addressing plant mortality, in particular, in future conservation research.

Since the national recovery was implemented 26 years ago, the natural mature tree population has declined 60%. Similarly, the numerous projects that were funded in that time to propagate plants and increase the tree population were characterized by extensive post-transplant mortality. This widespread tree death in natural forest settings has occurred without the inclusion of research scientists to observe the plant behavior, so the reasons for the ongoing mortality remain elusive.

One of UOG's first discoveries was that regeneration potential of the tree is considerable, a finding that refuted the long-standing belief that inadequate regeneration was among the defining extinction risks.

"It was gratifying to be involved in our choreographed trials designed to understand the seasonal aspects of seedling emergence and longevity traits," Cascasan said. "The decades-long belief that regeneration failure was a conservation limitation was inaccurate, as we revealed that recruitment from the seedling to the sapling stage was the primary limitation to population growth."

Deloso said these results on nursery and physiology issues are indicative of what can be learned in a short amount of time.

"The same can be achieved for the remaining unanswered questions if a change in methods is implemented, such that published academic scientists begin to be included in all funded conservation projects," he said.

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Further Reading: Marler, T.E., C. Musser, A.N.J. Cascasan, G.N. Cruz, B.E. Deloso. 2021. Adaptive Management Lessons for Serianthes nelsonii Conservation. Horticulturae 7: 43. doi:10.3390/horticulturae7030043.

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Researchers Name New Snake After Traditional Chinese Myth

A famous herpetologist died from a snakebite by a black-and-white banded krait during an expedition in northern Myanmar in 2001. The krait that caused his death was just confirmed to have been a venomous snake from a species that is new to science, following the examination of samples collected in 2016 and 2019 in China.

Duration: 01:18

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The skull of Bungarus suzhenae (3d-reconstructed model)

CREDIT

Jingsong Shi

The white snake spent 6000 years studying magic to change itself into a human, a young woman, who falls in love with a man, the rest is once upon a time.

BEAUTIFUL DEEP BLUE EYES

 

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Illustration of the Legend of the White Snake

CREDIT

Xin Wang, Chongqing museum of natural history

New deadly snake from Asia named after character from Chinese myth 'Legend of White Snake'

PENSOFT PUBLISHERS

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VIDEO: THE SKULL OF BUNGARUS SUZHENAE (3D-RECONSTRUCTED MODEL) view more 

CREDIT: JINGSONG SHI

In 2001, the famous herpetologist Joseph B. Slowinski died from snakebite by an immature black-and-white banded krait, while leading an expedition team in northern Myanmar. The very krait that caused his death is now confirmed to belong to the same species identified as a new to science venomous snake, following an examination of samples collected between 2016 and 2019 from Yingjiang County, Yunnan Province, China.

The new krait species, found in Southwestern China and Northern Myanmar, is described by Dr Zening Chen of Guangxi Normal University, PhD candidate Shengchao Shi, Dr Li Ding from the Chengdu Institute of Biology at the Chinese Academy of Sciences, Dr Gernot Vogel of the Society for Southeast Asian Herpetology in Germany and Dr Jingsong Shi of the Institute of Vertebrate Paleontology and Paleoanthropology at Chinese Academy of Sciences. Their study is published in the open-access, peer-reviewed journal ZooKeys.

The researchers decided to name the new species Bungarus suzhenae - Suzhen's krait, after the mythical figure of Bai Su Zhen - a powerful snake goddess from the traditional Chinese myth 'Legend of White Snake'.

The legend says that, after thousands of years of practicing magic power, the white snake Bai Su Zhen transformed herself into a young woman and fell in love with the human man Xu Xian. Together, they ran a hospital, saving lots of human lives with medicine and magic. However, this love between goddess and human was forbidden by the world of the gods and, eventually, Bai Su Zhen was imprisoned in a tower for eternity. Since then, the Chinese regard her as a symbol of true love and good-heartedness.

"The black-and-white banded krait is one of the snakes most similar to the white snake in nature, so we decided to name it after Bai Su Zhen," say the authors.

In fact, the discovery of Suzhen's krait was inspired by another accident from 2015, when the Chinese herpetologist Mian Hou was bitten by a black-and-white banded krait in Yingjiang. "It hurt around the wound, and the skin around it turned dark," said the unfortunate man, who luckily survived.

The authors of the present study realized that the bite was different from those of the many-banded krait B. multicinctus, which go without clear symptoms or pain around the wound. This clue eventually led to the discovery of Suzhen's krait.

Because kraits are highly lethal, understanding their species diversity and geographic distribution is vital for saving human lives. Thanks to adequate description and classification of deadly snakes, research on venom, antivenom development and proper snakebite treatment can advance more rapidly.

The new study makes it easier to distinguish between krait species from China and adjacent southeastern Asia. "Three species of the black-and-white banded kraits from China were previously put under the same name - many-banded krait, which would hinder appropriate medical treatment," the authors point out. Additionally, they suggest that antivenom for the many-banded krait be reevaluated accordingly.

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Original source

Chen Zening, Shi Shengchao, Gernot Vogel, Ding Li, Shi Jingsong (2021). Multiple lines of evidence reveal a new species of Krait (Squamata, Elapidae, Bungarus) from Southwestern China and Northern Myanmar. ZooKeys, 1025: 35-71. https://doi.org/10.3897/zookeys.1025.62305

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The new krait species Bungarus suzhenae

CREDIT

Dr Li Ding

 

Research identifies gender bias in estimation of patients' pain

A new study suggests that when men and women express the same amount of pain, women's pain is considered less intense based on gender stereotypes.

UNIVERSITY OF MIAMI

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"On a scale of one to 10, how much pain are you in?"

In a recent study published by the Journal of Pain, co-authored by Elizabeth Losin, assistant professor of psychology and director of the Social and Cultural Neuroscience lab at the University of Miami, researchers found that a patient's pain responses may be perceived differently by others based on their gender.

According to "Gender biases in estimation of others' pain," when male and female patients expressed the same amount of pain, observers viewed female patients' pain as less intense and more likely to benefit from psychotherapy versus medication as compared to men's pain, exposing a significant patient gender bias that could lead to disparities in treatments.

The study consisted of two experiments. In the first, 50 participants were asked to view various videos of male and female patients who suffered from shoulder pain performing a series of range of motion exercises using their injured and uninjured shoulders. Researchers pulled the videos from a database that contains videos of actual shoulder injury patients, each experiencing a range of different degrees of pain. The database included patients' self-reported level of discomfort when moving their shoulders.

According to Losin, the study likely provides results more applicable to patients in clinical settings compared to previous studies that used posed actors in their stimuli videos.

"One of the advantages of using these videos of patients who are actually experiencing pain from an injury is that we have the patients' ratings of their own pain," she explained. "We had a ground truth to work with, which we can't have if it's a stimulus with an actor pretending to be in pain."

The patients' facial expressions were also analyzed through the Facial Action Coding System (FACS)--a comprehensive, anatomically based system for describing all visually discernible facial movements. The researchers used these FACS values in a formula to provide an objective score of the intensity of the patients' pain facial expressions. This provided a second ground truth for the researchers to use when analyzing the data.

The study participants were asked to gauge the amount of pain they thought the patients in the videos experienced on a scale from zero, labeled as "absolutely no pain," and 100, labeled as "worst pain possible."

In the second experiment, researchers replicated the first portion of this study with 200 participants. This time, after viewing the videos, perceivers were asked to complete the Gender Role Expectation of Pain questionnaire, which measures gender-related stereotypes about pain sensitivity, the endurance of pain, and willingness to report pain.

Perceivers also shared how much medication and psychotherapy they would prescribe to each patient and which of these treatments they believed would be more effective in treating each patient.

The researchers analyzed the results of the participants' responses to the videos compared to the patient's self-reported level of pain and the facial expression intensity data. The ability to analyze observers' perceptions relative to these two ground truth measures of the patients' pain in the videos allowed the researchers to measure bias more accurately, Losin explained. That is because bias could be defined as different ratings for male and female patients despite the same level of responses.

Overall, the study found that female patients were perceived to be in less pain than the male patients who reported, and exhibited, the same intensity of pain. Additional analyses using participants' responses to the questionnaire about gender-related pain stereotypes allowed researchers to conclude that these perceptions were partially explained by these stereotypes.

"If the stereotype is to think women are more expressive than men, perhaps 'overly' expressive, then the tendency will be to discount women's pain behaviors," Losin said. "The flip side of this stereotype is that men are perceived to be stoic, so when a man makes an intense pain facial expression, you think, 'Oh my, he must be dying!' The result of this gender stereotype about pain expression is that each unit of increased pain expression from a man is thought to represent a higher increase in his pain experience than that same increase in pain expression by a woman."

What's more, psychotherapy was chosen as more effective than medication for a higher proportion of female patients compared to male patients.

Additionally, the study concluded that the gender of the perceivers did not influence pain estimation. Both men and women interpreted women's pain to be less intense.

The idea to study disparities in the perception of pain based on a patient's gender was derived from previous research, Losin said, that found women are often prescribed less treatment than men and wait longer to receive that treatment as well.

"There's a pretty wide literature showing demographic differences in pain report, the prevalence of clinical pain conditions, and then also a demographic difference in pain treatments," Losin pointed out. "These differences manifest as disparities because it seems that some people are getting undertreated for their pain based on their demographics."

Moving forward, Losin and her fellow researchers hope this study is a step in identifying and addressing gender disparities in health care. Co-authors of the study included the study's lead author, Lanlan Zhang, Guangzhou Sport University; Yoni K. Ashar, Weill Cornell Medical College; Leonie Koban, Paris Brain Institute; and senior author Tor D. Wager, Dartmouth College.

"I think one critical piece of information that could be conveyed in medical curricula is that people, even those with medical training in other studies, have been found to have consistent demographic biases in how they assess the pain of male and female patients and that these biases impact treatment decisions," Losin remarked. "Critically, our results demonstrate that these gender biases are not necessarily accurate. Women are not necessarily more expressive than men, and thus their pain expression should not be discounted."