Scientists record case of harmful bacteria in ubiquitous weed throughout US

Date: April 18, 2022

Source:  University of Florida  

Summary:  

Scientists have recorded the first North American case of a harmful phytoplasma disease known for its threat to fruit, vegetable and ornamental crops in South America and the Middle East. To make matters worse, scientists confirmed the host for the disease to be one of the most noxious and rapidly spreading weeds commonly found in a wide range of environments throughout the United States and into Canada.

FULL STORY


Scientists at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) have recorded the first North American case of a harmful phytoplasma disease known for its threat to fruit, vegetable and ornamental crops in South America and the Middle East.

To make matters worse, scientists confirmed the host for the disease to be one of the most noxious and rapidly spreading weeds commonly found in a wide range of environments throughout the United States and into Canada.

Findings of the "First report of 'Cadidatus Phytoplasma brasiliense' in North America and in a new host, yellow nutsedge (Cyperus esculentus)" were just published in the journal "Plant Health Progress."

"The host of the disease is known as one of the most widespread and problematic weeds found everywhere -- called yellow nutsedge," said Brian Bahder, assistant professor of entomology at UF/IFAS Fort Lauderdale Research and Education Center. "It is one of the most aggressive weeds that commonly grows in lawns, home landscapes, vegetable and flower gardens and agricultural systems."

The phytoplasma species called Candidatus Phytoplasma brasiliense is documented in regions of Brazil and Peru to harm hibiscus, papaya and cauliflower. Subsequently, research showed the same species infects peaches in the Middle East country of Azerbaijan.

Bahder and his team confirmed the phytoplasma and host in Fort Pierce. They found it while conducting research for a different disease -- Lethal Bronzing -- that attacks palm trees. Scientists were surveying and testing samples of grasses in hopes of finding a reservoir for lethal bronzing.

Research has shown that the adult planthopper insect that carries Lethal bronzing feeds on the palm's canopy, and the nymphs have been recorded among more than 40 species of grasses and sedges.

Because of the close association of nymphs with grasses and sedges, speculation has risen about the ability of these plants to serve as a reservoir for the Lethal bronzing phytoplasma, Bahder said.

For the survey, scientists sampled three of the most abundant weeds known to serve as a host to the nymphs, Yellow nutsedge being one of them.

While testing the samples, three of the outcomes resulted in a positive result.

"We thought we had found Lethal bronzing in one of the grasses, so we proceeded to genetically sequence the sample," said Bahder. "The results confirmed it was not lethal bronzing but that it was another phytoplasma."

The DNA sequencing of that specimen confirmed their findings of a new phytoplasma in this weed, recorded for the first time in North America.

Implications of the disease and its spread through this weed cause scientists to consider it a threat to agriculture and ornamental industries. UF/IFAS scientists are seeking funding for the next steps of research.

"The next logical step is to find out which insect is spreading the disease. The good news is that we caught this early," said Bahder. "We don't know if this is an isolated incident or if the insect is spreading in the grass, and if it will feed on the papaya, hibiscus or cauliflower -- which are economically important in Florida. The point is that we don't know the extent of this disease in Florida or what threat it poses.


Journal Reference:
Brandon Di Lella, De-Fen Mou, Ericka Helmick, Brian Bahder. First report of ‘Candidatus Phytoplasma brasiliense’ in North America and in a new host, yellow nutsedge (Cyperus esculentus). Plant Health Progress, 2022; DOI: 10.1094/PHP-03-22-0027-BR

Taylor Swift, the millipede: Scientists name a new species after the singer

Date: April 18, 2022

Source: Pensoft Publishers

Summary: 

Taylor Swift, an American singer known for her musical talents, has earned a new accolade. She now has a new species of millipede named after her. The new species of twisted-claw millipede was discovered in the mountains of Tennessee. Scientists described a total of 17 new species from the Appalachian Mountains.

FULL STORY

Taylor Swift, U.S. singer-songwriter known for hits such as "Shake It Off" and "You Belong With Me," has earned a new accolade -- she now has a new species of millipede named in her honor.

The twisted-claw millipede Nannaria swiftae joins 16 other new species described from the Appalachian Mountains of the United States. These little-known invertebrates have a valuable role as decomposers: breaking down leaf litter, they release their nutrients into the ecosystem. They live on the forest floor, where they feed on decaying leaves and other plant matter, and in fact, they are somewhat tricky to catch, because they tend to remain buried in the soil, sometimes staying completely beneath the surface.

Scientists Derek Hennen, Jackson Means, and Paul Marek, at Virginia Tech, U.S., describe the new species in a research paper published in the open access journal ZooKeys. The research was funded by a National Science Foundation Advancing Revisionary Taxonomy and Systematics grant (DEB# 1655635).

Because of their presence in museum collections, scientists long suspected that the twisted-claw millipedes included many new species, but these specimens went undescribed for decades. To fix this, the researchers began a multi-year project to collect new specimens throughout the eastern U.S. They traveled to 17 US states, checking under leaf litter, rocks, and logs to find species so that they could sequence their DNA and scientifically describe them.

Looking at over 1800 specimens collected on their field study or taken from university and museum collections, the authors described 17 new species, including Nannaria marianae, which was named after Hennen's wife. They discovered that the millipedes prefer to live in forested habitats near streams and are often found buried under the soil, exhibiting more cryptic behaviors than relatives.

The newly-described millipedes range between 18 and 38 mm long, have shiny caramel-brown to black bodies with white, red, or orange spots, and have white legs. The males have small, twisted and flattened claws on their anterior legs, which is the basis for their common name.

The lead author of the study, Derek Hennen, is a fan of Taylor Swift.

"Her music helped me get through the highs and lows of graduate school, so naming a new millipede species after her is my way of saying thanks," he says.


Journal Reference:
Derek A. Hennen, Jackson C. Means, Paul E. Marek. A revision of the wilsoni species group in the millipede genus Nannaria Chamberlin, 1918 (Diplopoda, Polydesmida, Xystodesmidae). ZooKeys, 2022; 1096: 17 DOI: 10.3897/zookeys.1096.73485

Nanoparticles prove effective against the yellow fever mosquito
Carbon black is fatal for its larvae in standing water

Date:April 19, 2022

Source: Ohio State University  

Summary:

Before being accidentally introduced to the New World by the 16th century slave trade, the yellow fever mosquito was a species native only to Africa. Highly adaptable, it has since become an invasive species in North America, but researchers at may have found a way to squash the pesky population in its juvenile stages.

FULL STORY

Before being accidentally introduced to the New World by the 16th century slave trade, the yellow fever mosquito was a species native only to Africa. Highly adaptable, it has since become an invasive species in North America, but researchers at The Ohio State University may have found a way to squash the pesky population in its juvenile stages.

Recently published in the journal Insects, a new paper describes how mosquitoes have evolved a natural resistance to some chemical insecticides, and offers an alternative called carbon black, a type of carbon-based nanoparticles, or CNPs.

Study co-author and an associate professor of entomology at Ohio State, Peter Piermarini described CNPs as "microscopic" materials made out of organic elements. The study used a modified version of carbon black called Emperor 1800, which is often used to coat automobiles black. While CNPs are a relatively new scientific development, they have been considered as new tools to control various insect and pest infestations, he said.

"If we can learn more about how carbon black works and how to use it safely, we could design a commercially available nanoparticle that is highly effective against insecticide-resistant mosquitoes," Piermarini said.

The yellow fever mosquito, or Aedes aegypti, is a species of mosquito known for spreading not just yellow fever, but also diseases like the Zika virus, dengue fever and chikungunya fever. Adults rarely fly more than a few hundred meters from where they emerge, but their abundance leads to steady transmission of diseases -- enough to claim tens of thousands of lives every year and hospitalize hundreds of thousands more people.

Because of this, the mosquito is considered to be one of the deadliest animals on the planet. For this study, the researchers' goal was to figure out how toxic these nanomaterials could be to mosquito larvae, or the immature form of the insect.

Contrary to popular belief, not all mosquitoes set their sights on turning our blood into their latest meal. Male mosquitoes subsist only on flower nectar; it's the females that will consume both flower nectar and blood in a bid to provide their eggs with enough protein to grow.

When female mosquitoes are ready to lay their eggs, they return to standing pools of water, like lakes or birdbaths, to release them. After they hatch, these larvae will stay in the water for about a week until they reach adulthood, and take wing.

To test whether Emperor 1800 would be effective in stopping that process, researchers worked with two different strains of the yellow fever mosquito inside the lab, one extremely susceptible to typical chemical insecticides, and the other, extremely resistant to them.

By applying the carbon black nanomaterials to the water during the earliest stages of the mosquito's life cycle and checking in 48 hours later, they were able to determine that CNPs kill mosquito larvae both quickly and efficiently.

"Given the properties of carbon black, it has the most potential for killing larvae because it can be suspended in water," Piermarini said. Their findings showed that the material seemed to accumulate on the mosquito larvae's head, abdomen, and even in its gut, meaning that at some point, the larvae were ingesting smaller particles of carbon black.

"Our hypothesis is that these materials may be physically obstructing their ability to perform basic biological functions. It could be blocking their digestion, or might be interfering with their ability to breathe," said Piermarini.

However, there was one thing that Piermarini found particularly surprising.

When first suspended in water, carbon black appeared equally toxic to larvae of insecticide-resistant and insecticide-susceptible mosquitoes, but the longer the carbon black was suspended in water before treating them. it became more toxic to the insecticide-resistant larvae.

"When you first apply the CNP solution it has similar toxicity against both strains," Piermarini said. "But when you let the suspension age for a few weeks, it tends to become more potent against the resistant strain of mosquitoes."

Although they couldn't determine the reason behind the time-lapsed deaths, the study concluded that these new nanomaterials could be extremely beneficial to controlling the species when applied as a preventive treatment to mosquito breeding grounds.

But before it can be utilized by the public, Piermarini said, carbon black needs to undergo rigorous testing to ensure it won't harm humans and the environment as a whole.

Co-authors were Erick Martinez Rodriguez, a visiting scholar currently in the Ohio State Entomology Graduate program, Parker Evans, a previous PhD student in the Ohio State Translational Plant Sciences Graduate program, and Megha Kalsi, a previous postdoctoral researcher in entomology. This research was supported by Ohio State's College of Food, Agricultural, and Environmental Sciences and Vaylenx LLC.

Journal Reference:
Erick J. Martínez Rodríguez, Parker Evans, Megha Kalsi, Noah Rosenblatt, Morgan Stanley, Peter M. Piermarini. Larvicidal Activity of Carbon Black against the Yellow Fever Mosquito Aedes aegypti. Insects, 2022; 13 (3): 307 DOI: 10.3390/insects13030307

Seafloor spreading has been slowing down
Sluggish spreading rates could mean a drop in greenhouse gas emissions from volcanoes

Date: April 14, 2022

Source: American Geophysical Union

Summary:

A new global analysis of the last 19 million years of seafloor spreading rates found they have been slowing down. Geologists want to know why the seafloor is getting sluggish.

FULL STORY

A new global analysis of the last 19 million years of seafloor spreading rates found they have been slowing down. Geologists want to know why the seafloor is getting sluggish.

New oceanic crust forms continuously along rifts thousands of miles long on the seafloor, driven by plate tectonics. As subduction pulls old crust down, rifts open up like fissures in an effusive volcano, drawing hot crust toward the surface. Once at the surface, the crust begins to cool and gets pushed away from the rift, replaced by hotter, younger crust.

This cycle is called seafloor spreading, and its rate shapes many global processes, including sea level and the carbon cycle. Faster rates tend to cause more volcanic activity, which releases greenhouse gases, so deciphering spreading rates helps contextualize long-term changes in the atmosphere.

Today, spreading rates top out around 140 millimeters per year, but peaked around 200 millimeters per year just 15 million years ago in some places, according to the new study. The study was published in the AGU journal Geophysical Research Letters, which publishes high-impact, short-format reports with immediate implications spanning all Earth and space sciences.

The slowdown is a global average, the result of varying spreading rates from ridge to ridge. The study examined 18 ridges, but took a particularly close look at the eastern Pacific, home to some of the globe's fastest spreading ridges. Because these slowed greatly, some by nearly 100 millimeters per year slower compared to 19 million years ago, they dragged down the world's average spreading rates.

It's a complex problem to solve, made more difficult by the seafloor's slow and steady self-destruction.

"We know more about the surfaces of some other planets than we do our own seafloor," said Colleen Dalton, a geophysicist at Brown University who led the new study. "One of the challenges is the lack of perfect preservation. The seafloor is destroyed, so we're left with an incomplete record."

The seafloor is destroyed in subduction zones, where oceanic crust slides under continents and sinks back into the mantle, and is reforged at seafloor spreading ridges. This cycle of creation and destruction takes about every 180 million years, the age of the oldest seafloor. The crust's magnetic record tracks this pattern, producing identifiable strips every time the Earth's magnetic field reverses.

Dalton and her co-authors studied magnetic records for 18 of the world's largest spreading ridges, using seafloor ages and their areas to calculate how much ocean crust each ridge has produced over the last 19 million years. Each ridge evolved a little differently: some lengthened, some shrank; some sped up, but almost all slowed down. The overall result of Dalton's work is that average seafloor spreading slowed down by as much as 40% over that time.

The driver here might be located at subduction zones rather than spreading ridges: for example, as the Andes grow along the western edge of the South American continent, the mountains push down on the crust.

"Think of it as increased friction between the two colliding tectonic plates," Dalton said. "A slowdown in convergence there could ultimately cause a slowdown in spreading at nearby ridges." A similar process could have operated underneath the Himalaya, with the rapidly growing range slowing spreading along the ridges in the Indian Ocean.

However, Dalton points out, this added friction can't be the only driver of the slowdown, because she found slowing rates globally and mountain growth is regional. Larger-scale processes, like changes in mantle convection, could also be playing a role. In all likelihood, she concludes, it's a combination of both. To learn more, Dalton hopes to collect absolute plate speeds, rather than the relative speeds used in this study, which will better allow her to determine the cause of the slowdown.

Journal Reference:
Colleen A. Dalton, Douglas S. Wilson, Timothy D. Herbert. Evidence for a Global Slowdown in Seafloor Spreading Since 15 Ma. Geophysical Research Letters, 2022; 49 (6) DOI: 10.1029/2022GL097937

Witches, Disgust, and Anti -abortion Propaganda in Imperial Rome

 Introduction

The stark contrast between Greek and Roman literary depictions of witches, though well known, remains puzzling. The relatively abrupt shift from young, beautiful, desirable sorceress to elderly, hideous, disgusting hag reached its peak between the late first century B.C.E. and the mid-first century C.E., but why? 1

 The answer may relate to a specifically male source of distress that reached a near-panic point during this time period: a perceived decline in both morals and in population, especially among the aristocracy. Women's sexual behavior during this time was of particular concern, an anxiety reflected in Augustan policies designed to encourage marriage and children (Spaeth 2014, 54). Concomitantly, any action that might prevent childbearing was greeted with animosity, and literature of the Augustan age and the decades following expressed particular hostility toward the practice of abortion. This especial antipathy seems to have made its way into descriptions of witches in Roman literature, which are peculiarly tied not just to the murder of children, but to the killing of unborn children.

 1.For detailed discussions of this contrast, including the witches' physical appearances, behavior, and motivation, see especially Pollard (2008) and Spaeth (2014). Even Greek figures such as Circe and Medea, when rendered into Latin literature, become far less appealing (Spaeth 2014,42). I use Spaeth's definition for Witch (2014, 41), essentially a woman claiming or popularly believed to be a practitioner of magic. Also, I adhere to the distinction between Greek and Roman literary depictions as having no relation to whether the witch herself is Greek or Roman; a number of witches in Roman literature are Thessalian (e.g. Erictho, Meroe, and Panthia),Thessaly being the legendary home of many witches in classical literature

Medication “Abortion Pills” Safe for Early Use in Patients Even With Pregnancies of Unknown Location

By BRIGHAM AND WOMEN'S HOSPITAL APRIL 17, 2022

The medication combination of mifepristone and misoprostol, referred to as “abortion pills,” is highly effective for early abortion and early pregnancy loss. Typically, when patients have not yet had an intrauterine pregnancy confirmed by ultrasonogram, they are followed with serial blood tests (hCG) and a repeat ultrasonogram to ‘rule out’ ectopic pregnancy — a life threatening condition in which a fertilized egg has implanted outside the uterus and will not be viable.

In a retrospective cohort study, researchers from the Brigham compared the safety and efficacy of immediately starting the medication combination after a person has a positive pregnancy test versus waiting to initiate treatment until a diagnosis of ectopic pregnancy has been ruled out.

The researchers found that administering the pills as early as possible could be done safely and could also help the patient determine if their pregnancy was an ectopic pregnancy or not faster than if they had waited for an ultrasonogram. Researchers found no evidence of an increase in the rates of serious adverse events, emergency department visits, or nonadherence with follow-up. However, the team did see a higher failure rate for the pills when given early, meaning that patients with an undesired pregnancy who are treated early may need to re-initiate a medical abortion.

“This study should encourage clinicians to shift clinical practice to meet the demand of patients and facilitate an approach of ‘the sooner, the better,’ which is what many patients want,” said corresponding author Alisa Goldberg, MD, MPH, of the Department of Obstetrics and Gynecology.

“Our data suggest that there is no reason to mandate that patients with pregnancies of unknown location delay initiating abortion to first obtain a definitive diagnosis. In contrast, there is diagnostic and therapeutic benefit to administering abortion medications to patients with undesired pregnancy of unknown location.”

Reference: “Mifepristone and Misoprostol for Undesired Pregnancy of Unknown Location” by Goldberg, Alisa B. MD, MPH; Fulcher, Isabel R. PhD; Fortin, Jennifer MPH; Hofer, Rebecca K. MD; Cottrill, Alex BA; Dethier, Divya MD; Gilbert, Allison MD, MPH; Janiak, Elizabeth ScD and Roncari, Danielle MD, MPH, 7 April 2022, Obstetrics and Gynecology.
DOI: 10.1097/AOG.0000000000004756

Witnessing parental domestic violence in childhood linked to mental illness in adulthood

Adults exposed to chronic parental domestic violence have an elevated prevalence of depression, anxiety and substance abuse disorders, and lower levels of social support than their peers who did not experience this childhood adversity

Peer-Reviewed Publication

UNIVERSITY OF TORONTO

A new study from the University of Toronto found that one-fifth (22.5%) of adults who were exposed to chronic parental domestic violence during childhood developed a major depressive disorder at some point in their life. This was much higher than the 9.1% of those without a history of parental domestic violence.

"Our findings underline the risk of long-term negative outcomes of chronic domestic violence for children, even when the children themselves are not abused,” says author Esme Fuller-Thomson, Director of University of Toronto’s Institute for Life Course and Aging at the University of Toronto and Professor at the Factor-Inwentash Faculty of Social Work (FIFSW). “Social workers and health professionals must work vigilantly to prevent domestic violence and to support both survivors of this abuse and their children"

Parental domestic violence (PDV) often occurs in the context of other adversities, including childhood physical and sexual abuse, making it challenging to examine the mental health outcomes associated solely with parental domestic violence in the absence of childhood abuse. To address this problem, the authors excluded anyone in their study who had experienced childhood physical or sexual abuse. The study’s nationally representative sample ultimately included 17,739 respondents from the Canadian Community Health Survey-Mental Health, of whom 326 reported having witnessed PDV more than 10 times before age 16, which was defined as ‘chronic PDV’.

One in six adults (15.2%) who had experienced chronic PDV reported that they later developed an anxiety disorder. Only 7.1% of those who had not been exposed to parental violence also reported experiencing an anxiety disorder at some point in their life.

“Many children who are exposed to their parent’s domestic violence remain constantly vigilant and perpetually anxious, fearful that any conflict may escalate into assault. Therefore, it is not surprising that decades later, when they are adults, those with a history of PDV have an elevated prevalence of anxiety disorders,” said co-author Deirdre Ryan‑Morissette, a recent Masters of Social Work graduate from University of Toronto’s FIFSW.

More than one-quarter of adults (26.8%) who were exposed to chronic PDV in childhood developed substance use disorders, compared to 19.2% of those without exposure to this early adversity. 

However, the findings were not all negative. More than three in five adult survivors of chronic PDV were in excellent mental health, free from any mental illness, substance dependence or suicidal thoughts in the preceding year; were happy and/or satisfied with their life and reported high levels of social and psychological well-being, despite their exposure to such harrowing experiences in childhood. Although the prevalence of flourishing mental health was lower among those exposed to chronic PDV in comparison to those whose parents were not violent with each other (62.5% vs 76.1%), it was still much higher than the authors had expected.

“We were encouraged to discover that so many adults overcame their exposure to this early adversity and are free of mental illness and thriving,” said co-author Shalhevet Attar-Schwartz, Professor at Hebrew University’s Paul Baerwald School of Social Work and Social Welfare. “Our analysis indicated that social support was an important factor. Among those who had experienced PDV, those who had more social support had much higher odds of being in excellent mental health.”

The study was limited by several factors. The Canadian Community Health Survey did not include important information about the PDV such as the duration in years, the respondent’s relationship to the perpetrator of the violence, or the severity of the violence. The study was based on cross-sectional data gathered at one point in time; it would have been much preferable to have longitudinal rather than cross-sectional data.

“Our study highlights the need for more research on interventions for mental illness, substance use disorders, and social isolation among those with PDV exposure, with the goal of having a greater proportion of those experiencing childhood adversities obtaining optimal mental health” said Fuller-Thomson.

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JOURNAL

Journal of Family Violence

DOI

10.1007/s10896-022-00390-w 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Achieving Optimal Mental Health Despite Exposure to Chronic Parental Domestic Violence: What Pathways are Associated with Resilience in Adulthood?

Peatland plants hide responses to environmental change

Fine roots grow dramatically faster in an experimentally warmed peatland

DOE/US DEPARTMENT OF ENERGY

image: Shrub fine-roots, often finer than human hair, tangled around a Sphagnum moss stem. The fate of these seemingly tiny plant components is closely tied to carbon cycling of peatlands, which are important to the planet as carbon sinks. view more 

Credit: Photo credit: Colleen Iversen, Oak Ridge National Laboratory

The Science

Lands covered in peat, a mix of partially decayed organic material, store a significant amount of carbon. These peatlands are vulnerable to global changes in temperature. Researchers expect the response of plants in peatlands to warming climates to influence future carbon uptake and storage. However, researchers do not fully understand this mechanism, especially below ground level. Researchers at the Spruce and Peatland Responses Under Changing Environments (SPRUCE) whole-ecosystem warming experiment studied processes below ground. They found that warming and the resulting soil drying, significantly increased the growth of fine roots. The magnitude of this belowground response is 20 times greater than previously observed in similar experiments from upland ecosystems.

The Impact

Previous studies have found increases in the abundance of shrub, or “shrubification,” in northern peatlands under warmer conditions. This new work highlights belowground mechanisms that enable shrubs to rapidly adapt to warmer and drier conditions. Data collected on fine roots will enable researchers to better represent peatlands in Earth system models.

Summary

Belowground responses to climate change are a key unknown in the Earth system. Plants’ fine-root response is especially important to understand because fine roots respond quickly to environmental change, are responsible for nutrient and water uptake, and influence ecosystem carbon cycling. However, fine-root responses to climate change are poorly constrained, especially in northern peatlands, which contain up to two-thirds of the world’s soil carbon. Using a whole-ecosystem warming manipulation, researchers at SPRUCE found that warming strongly increased ecosystem fine-root growth. Soil moisture negatively correlated with fine-root growth, highlighting how drying of these typically water-saturated ecosystems can fuel a surprising burst in shrub belowground productivity. This is one possible mechanism explaining the “shrubification” of northern peatlands in response to global change. This previously unrecognized belowground mechanism sheds light on how peatland fine-root response to warming and drying could be strong and rapid, with consequences for the belowground growing season duration, microtopography, vegetation community structure, and ultimately, carbon function of these globally relevant carbon sinks.

Funding

The Spruce and Peatland Responses Under Changing Environments (SPRUCE) experiment is supported by the Department of Energy Office of Science, Office of Biological and Environmental Research.

Publications

Malhotra A., et al., Peatland warming strongly increases fine-root growth. PNAS 117 (30) 17627-17634 (2020). [DOI: 10.1073/pnas.2003361117]

Measuring nature’s effects on physical and mental health

Scales developed by a Texas A&M professor could inform future interventions for getting adults to spend more time outdoors.

Peer-Reviewed Publication

TEXAS A&M UNIVERSITY

A study recently published in BMC Psychology outlines two scales created to measure factors related to time spent in nature, a first step in exploring how this affects health and well-being.

The scales were developed by a multidisciplinary team led by Jay Maddock, professor in the Department of Environmental and Occupational Health at the Texas A&M University School of Public Health.

A body of evidence has shown that time spent in nature, or TSN, is associated with physical and mental health, yet most American adults spend very little time in green or natural spaces. Two strong predictors of health behaviors are self-efficacy and intentions. However, scales to measure these factors have not yet been developed and are needed to create effective, evidence-based interventions to increase TSN.

The researchers used a nine-phase procedure to construct, refine and test the scales. The first phase identified self-efficacy and intentions as the factors that would be measured by the scales. “Self-efficacy” was defined as “a person’s confidence in his or her ability to take action and to persist in that action despite obstacles or challenges pertaining to spending time in nature.” Next, “Intentions” were defined as “planning to engage in certain nature-related behaviors over the next three months.” The first phase also involved initial generation of items to include in a survey to measure these factors.

Respondents were asked how confident they were that they “could spend at least two hours per week in green or natural spaces” under conditions including weather, stress, accessibility, scheduling or costs. They also were asked if they intended to participate in nature-related activities such as going outdoors, hiking or visiting parks in the next three months.

The survey was administered to a nationwide sample of more than 2,000 adults.

Spending more time in nature was found to correlate with both self-efficacy and intentions, suggesting that future interventions to improve TSN should have increasing confidence to spend time in nature as a goal. Both factors negatively correlated with age, indicating diminishing confidence that could be related to mobility or safety concerns that increase as adults age. Male respondents had higher self-efficacy than female respondents, a finding that agrees with other research showing that women are less likely to participate in recreational activities in nature despite showing a preference for doing so.

Development of the scales is just the first step of what the researchers hope will be a series of studies with the ultimate goal of finding ways to improve health and well-being through increased TSN.

“We’re working on developing a whole suite of measures,” Maddock said. “Once those are done, we’re going to be looking to develop theory-based interventions to increase time spent in nature.”

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JOURNAL

BMC Psychology

DOI

10.1186/s40359-022-00764-1 

METHOD OF RESEARCH

News article

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Development and validation of self-efficacy and intention measures for spending time in nature

Windows to the soul: Pupils reveal ‘aphantasia’ – the absence of visual imagination

Picture this, if you will: Aphantasia can be detected with an eye-opening look into our pupils.

Peer-Reviewed Publication

UNIVERSITY OF NEW SOUTH WALES

 

IMAGE: THE PUPILLARY REFLEX IS AN ADAPTION THAT OPTIMISES THE AMOUNT OF LIGHT HITTING THE RETINA, CHANGING, EVEN, IN RESPONSE TO IMAGINED OBJECTS - NOT SO FOR APHANTASIC INDIVIDUALS. PHOTO: UNSPLASH/AMANDA DALBJORN view more 

CREDIT: AMANDA DALBJORN/UNSPLASH

The study, led by researchers from UNSW Sydney and published in eLife, found that the pupils of people with aphantasia did not respond when asked to imagine dark and light objects, while those without aphantasia did.

To first gauge the pupillary reflex of non-aphantasic people, the researchers sought 42 study participants, self-reported as having a visual imagination, and fitted them with glasses to track their eye movements and pupil sizes.

Participants were then exposed to bright or dark shapes against a grey background, which predictably evoked pupillary constriction in response to bright shapes (comparable to looking up at a bright sky) and pupillary dilation in response to dark shapes (after switching a light off).

Next, to test visual imagery – the mind’s capacity to visualise objects – participants were asked to simply imagine those same light or dark shapes (with their eyes open, for their pupils to be tracked) and subsequently report the ‘vividness’ of that imagery.

The researchers found that even in response to imagined bright and dark shapes, the participants’ pupils still constricted and dilated appropriately, a pupillary response that was larger in those reporting greater imagery vividness.

“The pupillary reflex is an adaption that optimises the amount of light hitting the retina,” says Professor Joel Pearson, senior author on the paper. “And while it was already known that imagined objects can evoke so-called ‘endogenous’ changes in pupil size, we were surprised to see more dramatic changes in those reporting more vivid imagery. This really is the first biological, objective test for imagery vividness.”

Testing for a lack of imagination

Finally, with the link between visual imagery and pupillary response established, the researchers sought to test the effect in aphantasic individuals. The researchers repeated the study with 18 participants self-reporting aphantasia.

Exposing participants to bright and dark shapes, the researchers found that aphantasic individuals exhibited the same pupillary response as the general population: constriction to bright, dilation to dark.

However, during the study’s second component where participants were asked to visualise those same shapes, the pupillary response of aphantasic individuals did not significantly differ in response to imagined dark versus imagined bright objects.

“One of the problems with many existing methods to measure imagery is that they are subjective, that is to say they rely on people being able to accurately assess their own imagery. Our results show an exciting new objective method to measure visual imagery,” says Prof Pearson, “and the first physiological evidence of aphantasia. With over 1.3 million Australians thought to have aphantasia, and 400 million more internationally, we are now close to an objective physiological test, like a blood test, to see if someone truly has it.”

To ensure the aphantasic participants were really attempting imagery, the researchers included a further experimental condition, requesting aphantasic individuals to visualise four shapes, instead of one.

While the pupils of those with aphantasia showed no difference when imagining light versus dark objects, they did show a difference imagining one versus four objects, suggesting more mental effort, thereby negating an explanation of non-participation by aphantasic individuals.

“Our pupils are known to get larger when we are doing a more difficult task,” says Lachlan Kay, PhD candidate in the Future Minds Lab, UNSW. “Imagining four objects simultaneously is more difficult than imagining just one. The pupils of those with aphantasia dilated when they imagined four shapes compared to one, but did not change based on the whether the shapes were bright or dark. This indicated that the participants with aphantasia were indeed trying to imagine in this experiment, just not in a visual way”.

“The aphantasic pupil response to the four objects condition is also a really exciting finding,” adds Prof Pearson, “because for the first time we have strong biological evidence that those with aphantasia are really trying to create a mental image, putting to rest claims that they may simply not be attempting to create a mental image.”

"These findings are also really interesting in regard to memory and aphantasia,” said Dr Rebecca Keogh, Postdoctoral research fellow based at Macquarie University and another author of the study. “Our previous work has shown that aphantasic individuals are able to perform visual working memory tasks, remembering many images for a short period of time, without using visual imagery.

“These findings further highlight the wide variability of the human mind that can often remain hidden until we ask someone about their internal experiences or invent new ways to measure the mind. It reminds us that just because I remember or visualise something one way, doesn’t mean everyone does.”

What’s next for aphantasia research? A look into the future…

Next, Prof Pearson and his team at the Future Minds Lab plan to investigate how this new method could be scaled up and run online to allow a global, efficient and objective measurement of imagery and aphantasia.

“This really is an exciting time. We are very close to having objective, reliable tests for extreme imagery, aphantasia and hyperphantasia (extremely strong visual imagery) that could be scaled up to run online for millions of people everywhere,” says Prof Pearson.

“We know that thinking in pictures or not affects the number of details in lifelong memories, how emotional we get when reading, and how we hold things in short term memory. This new method will allow us to understand the brain mechanisms of extreme imagery and the global implications for how we think, make decisions and feel.”

-ENDS-

 

Prof Joel Pearson from UNSW Science’s Future Minds Lab is available for interview upon request. Please contact Jesse Hawley.

Paper DOI: 10.7554/eLife.72484

To be involved in this type of research and learn more about aphantasia, hyperphantasia and the Future Minds Lab, visit https://www.futuremindslab.com/extremeimagery

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JOURNAL

eLife

DOI

10.7554/eLife.72484 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

The pupillary light response as a physiological index of aphantasia, sensory and phenomenological imagery strength