Novel study of high-potency cannabis shows some memory effects

WASHINGTON STATE UNIVERSITY

Research News

 

PULLMAN, Wash. - Even before the pandemic made Zoom ubiquitous, Washington State University researchers were using the video conferencing app to research a type of cannabis that is understudied: the kind people actually use.

For the study, published in Scientific Reports, researchers observed cannabis users over Zoom as they smoked high-potency cannabis flower or vaped concentrates they purchased themselves from cannabis dispensaries in Washington state, where recreational cannabis use is legal. They then gave the subjects a series of cognitive tests.

The researchers found no impact on the users' performance on decision-making tests in comparison to a sober control group but did find some memory impairments related to free recall, source memory and false memories.

While the findings are in line with previous research on low-potency cannabis, this study is one of the few to investigate cannabis that contains much more than 10% tetrahydrocannabinol (THC), the plant's main psychoactive ingredient. This is only the second known study to examine the effect of cannabis concentrates.

"Because of federal restrictions to researchers, it was just not possible to study the acute effects of these high-potency products," said Carrie Cuttler, WSU psychologist and lead researcher on the study. "The general population in states where cannabis is legal has very easy access to a wide array of high- potency cannabis products, including extremely high-potency cannabis concentrates which can exceed 90% THC, and we've been limited to studying the whole plant with under 10% THC."

While 19 states and Washington D.C. have legalized cannabis for recreational use, the U.S. federal government still classifies it as a Schedule 1 drug, implying it has a high potential for abuse and no medicinal benefits. Until recently, researchers interested in studying cannabis were limited to using low-potency plants of around 6% THC supplied by the National Institute of Drug Abuse. In June, the U.S. Drug Enforcement Administration indicated it may allow some companies to start growing cannabis for research purposes.

For this study, which began in 2018, Cuttler and her colleagues found a way to study the effects of high-potency cannabis while still complying with federal guidelines. The study participants bought their own products and used them in their own homes. They were never in a laboratory on federal property, and the researchers never handled the cannabis themselves. Participants were not reimbursed for their purchase. Instead they were compensated for their time with Amazon gift cards. All participants were over 21 and experienced cannabis users who reported no past negative reactions to cannabis like panic attacks. The study's method was cleared by WSU Division of the Office of the Attorney General and the university's research ethics board.

The 80 participants were divided into four groups: two groups used cannabis flower with more than 20% THC but one containing cannabidiol (CBD), a non-psychoactive component of cannabis, and the other without CBD. Another group vaped cannabis concentrates with more than 60% THC that included CBD. A fourth group remained sober.

For all cannabis using groups, the researchers found no effect on a range of decision-making tests including risk perception and confidence in knowledge. On a few memory tests there were also no significant differences between the cannabis-using and sober groups, including prospective memory, the ability to remember to do things at a later time, such as attend an appointment. The cannabis-using participants also did well on temporal order memory, the ability to remember the sequence of previous events.

However, the groups that smoked cannabis flower with CBD did worse on verbal free recall trials- they were unable to recall as many words or pictures that were shown to them compared to the sober group. This finding was contrary to a small number of previous studies indicating CBD might have a protective effect on memory. The groups that used cannabis without CBD and the group that used concentrates, performed worse on a measure of source memory which means being able to distinguish the way previously learned information was presented.

Finally, all three cannabis-using groups did poorly on a false memory test - when given a new word and asked if it had been presented before, they were more likely to say it had when it had not.

There was also an unexpected finding: people who vaped the high-potency concentrates with more than 60% THC performed comparably to those who smoked cannabis flower. This may have been because they tended to self-titrate - using less of the drug to achieve a similar level of intoxication and impairment as the people who smoked the less-potent cannabis flower.

Cuttler said this was cause for cautious optimism on the little-studied but widely available concentrates.

"There's been a lot of speculation that these really high-potency cannabis concentrates might magnify detrimental consequences, but there's been almost zero research on cannabis concentrates which are freely available for people to use," said Cuttler. "I want to see way more research before we come to any general conclusion, but it is encouraging to see that the concentrates didn't increase harms."

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Faulty memories of our past whereabouts: The fallacy of an airtight alibi

ASSOCIATION FOR PSYCHOLOGICAL SCIENCE

Research News

 

When someone is suspected of criminal activity, one of the most important questions they are asked is if they have a credible alibi. Playing back past events in our minds, however, is not like playing back a video recording. Recollections of locations, dates, and companions can become muddled with the passage of time. If a suspect's memories are out of line with documented events, a once-plausible alibi can crumble and may be seen as evidence of guilt.

To put people's memories of past whereabouts to the test, a team of researchers tracked the locations of 51 volunteers for one month and found that their recollections were wrong approximately 36% of the time.

"This is the first study to examine memory for where an event happened," said Simon J. Dennis, director of the Complex Human Data Hub at the University of Melbourne's School of Psychological Sciences and lead author of the study, which was published in the journal Psychological Science. "We were able to use experience-sampling methods to actually examine people's memories and analyze what is affecting memory error in their everyday life."

In the study, an app on the participants' smartphones continuously (and securely) recorded their locations and surroundings via GPS. The app also made sound recordings of the environment every 10 minutes. Participants had the freedom to turn off the app or to delete events--a mechanism designed to protect privacy.

At the end of the month, the participants received a memory test in which they were given a time and date and then asked to select one of four markers on Google Maps to show where they had been at that moment.

The results revealed that participants tended to confuse days across weeks. They also often confused weeks in general and hours across days. The participants had the poorest recall when memories of one event become entwined with memories of a similar experience, such as filling up a car with gas at a different location of the same gas-station chain.

Additionally, the researchers found that people tended to confuse places they had visited at similar times or locations, such as multiple bars visited in one evening. People also made mistakes--although less frequently--when events involved similar sounds or movement patterns, such as when they had walked through town on different days while listening to their favorite music.

"This has implications for alibi generation, as jurors tend to assume that a suspect who is wrong is lying," said Dennis. "These results can alert investigators to the questions they should ask in order to catch the memory errors that suspects are likely to make."

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Reference: Laliberete, E., Yim, H., Stone, B., & Dennis, S. (2021). The fallacy of an airtight alibi: Understanding human memory for "where" using experience sampling. Psychological Science, 23(6), 944-951https://doi.org/10.1177/0956797620980752

Additional research can be found in the APS Research Topic on Memory.

 

CAMH releases updated national clinical guidelines for treatment of opioid use disorder

Harmonization of guidelines across Canada will improve consistency and quality of care amid worsening opioid epidemic

CENTRE FOR ADDICTION AND MENTAL HEALTH

Research News

As more evidence emerges that opioid overdose deaths have increased dramatically since the onset of COVID-19, the Centre for Addiction and Mental Health (CAMH), in collaboration with subject matter experts and medical regulatory authorities across Canada, have now released updated national clinical guidelines for the treatment of opioid use disorder. Opioid Agonist Therapy: A Synthesis of Canadian Guidelines for Treating Opioid Use Disorder, harmonizes existing provincial and national guidelines, evidence-based practices, and expert opinions into one document aimed at providing consistent and high-quality care to people with opioid use disorder.

First-line treatment for those with opioid use disorder is opioid agonist therapy (OAT). This includes providing a medication that keeps the person out of withdrawal, reduces their cravings and prevents overdose deaths should they relapse. These medications are the most effective treatment option for opioid use disorder, and are scientifically proven to save lives, even when people use fentanyl. When combined with counselling and addressing the social causes and consequences of addiction, the person can make a full recovery and get back to living their lives. OAT is a long-term treatment and it can take some people a few tries before they get better completely.

"COVID has drastically changed the situation on the ground across Canada in regards to the opioid crisis and these need to be living guidelines that can be updated as circumstances change and new evidence evolves," said Dr. Peter Selby, Clinician Scientist, Addictions Division, and CAMH lead for this initiative. "For example, we wanted to change some of the old rules that were making it hard to provide person-centred care and help people stay in treatment. That is key because the longer people are in treatment the better they recover and the less likely they are to die from an opioid overdose."

The new guidelines are updated with the most up-to-date information and clinically-proven strategies to help patients overcome opioid addiction. These include updated medication delivery options, such as offering injectables, and expanding the list of medications for those who don't respond to traditional treatments. The guidelines also feature less regulatory restriction and new strategies to combat stigma to make treatment adherence easier.

"OAT, like any other substance use treatment, needs to meet every patient's individualized needs and goals," added Dr. Narges Beyraghi, CAMH Addictions Psychiatrist. "The recovery journey is different for every individual and they may connect to different components of care during this process. This updated guideline has tried to be inclusive to a patient's gender, age and other physical and mental health problems that could be a barrier to access to care or equitable care."

A CAMH study released in April found that a large number of people who were regular opioid users when the pandemic began reported heightened fears of dying from an overdose, in large part because of disruptions in the supply of street drugs that made drugs more expensive, harder to get and of unknown origin or potency. Lockdown measures across the country also increased the risk that people would use alone without anyone to help them in the event of an overdose. This risk was compounded by reduced access to harm reduction services like safe injection centres. All of these factors led experts to fear that the COVID pandemic would make the opioid crisis more deadly, and new numbers recently released by Ontario Public Heath confirmed those fears, with a 60 per cent increase in opioid deaths reported.

Dr. Marina Reinecke, Medical Consultant, Prescribing Practices Program, The College of Physicians & Surgeons of Manitoba, said: "Opioid use disorder affects a large and diverse group of Canadians. In Manitoba, our patients live in urban, rural and remote locations and have diverse care needs. These needs often collide with inequitable access to health care services. This compounds the tragedy associated with this very treatable disease. These guidelines provide evidence-based guidance and practical information for frontline clinicians in every care setting, empowering them to bring hope and health to Canadians where they live."

"However, guidelines alone don't change practice," added Dr. Beyraghi. "What does change practice is a combination of policy changes to address structural and societal stigma and education. We have several courses at CAMH that help providers acquire and improve their skills in treating people with opioid use disorder in a humane and respectful manner. We also have great resources for people who use opioids and their loved ones to make a science-based informed choice about treatment."

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Visit the CAMH website to learn more about the updated opioid use disorder guidelines, as well as additional resources regarding OAT.

 

Study: Hospitals not adequately prepared for next pandemic

Use of new preparedness tool can help hospitals determine their ability to respond to unexpected surges due to mass shootings, terrorist attacks, or future pandemics 

UNIVERSITY OF MARYLAND SCHOOL OF MEDICINE

Research News

 

As the COVID-19 pandemic wanes in the U.S., a new study from the University of Maryland School of Medicine (UMSOM) and University of Maryland Medical Center (UMMC) finds that hospitals nationwide may not be adequately prepared for the next pandemic. A 10-year analysis of hospitals' preparedness for pandemics and other mass casualty events found only marginal improvements in a measurement to assess preparedness during the years leading up to the COVID-19 pandemic. The study was published last month in the Journal of Healthcare Management.

"Our work links objective healthcare data to a hospital score that assesses the ability to save lives in a disaster," said study lead author David Marcozzi, MD, Professor of Emergency Medicine at UMSOM and Chief Clinical Officer/Senior Vice President at UMMC. "It attempts to fill a glaring gap in the national conversation on the need for improved assessments of and the opportunity for better hospital planning to assure readiness."

To conduct the research, Dr. Marcozzi, who is also the COVID-19 Incident Commander for the University of Maryland Medical System, and his colleagues first developed and published a surge index tool that linked standard reported hospital information to healthcare preparedness elements.  The tool, called the Hospital Medical Surge Preparedness Index (HMSPI), used data from 2005 to 2014 to produce a score designed to predict how well a hospital can handle a sudden influx in patients due to a mass shooting or infectious disease outbreak.  Such data included the size of the medical staff, the number of hospital beds, and the amount of equipment and supplies.

Medical surge capacity is an important measure to assess a hospital's ability to expand quickly beyond normal services to meet an increased demand for healthcare. The Las Vegas mass shooting in 2017, for example, sent more than 500 concertgoers to local hospitals. During the early weeks of the COVID-19 pandemic, New York City hospitals were under siege with 4,000 patients hospitalized. To calculate the HMSPI, researchers input data from four important metrics.

Staff: Doctors, nurses, pharmacists, respiratory technicians and others

Supplies: Personal protective equipment, cardiac monitors, sterile bandages, and ventilators

Space: Total beds and number of beds that current staff can handle

Systems: Framework for enabling electronic sharing of files and information between departments and multiple hospitals

In the new study, Dr. Marcozzi and his colleagues used data from the American Hospital Association's annual surveys of more than 6,200 hospitals nationwide that were collected from 2005 to 2014. They also employed data from the U.S. Census Bureau to determine population estimates in cities and the Dartmouth Atlas Project to establish the geographic service area of each hospital. They combined the hospital metrics gleaned from the AHA's annual surveys with the geographic data to calculate HMSPI composite scores for hospitals in each state.

Their evaluation found varying levels of increases in HMSPI scores from 2005 to 2014 in every state, which could indicate that states are becoming better prepared to handle a medical surge. The scores also indicated that ideal readiness had not yet been achieved in any state before the COVID-19 pandemic.

"This is just the starting point. We need to better understand the ability of our nation's hospitals to save lives in times of crisis," said Dr. Marcozzi.  This information, and follow-up studies building from this work, will be key to better matching states' healthcare resources to their population to assure optimal care is delivered.  Dr. Marcozzi described one follow-up study that would be impactful would be to use data from the COVID-19 pandemic to see whether the index was predictive to indicate which hospitals were most prepared for the pandemic surge based on their patient outcomes.

"This pioneering work is a needed advancement that could allow for a transparent assessment of a hospital's ability to save lives in a large-scale emergency," Dr. Marcozzi said. "The COVID-19 pandemic demonstrated that there is still plenty of room for improvement in the ability of our nation's healthcare system to triage and manage multiple patients in a crisis and that translates into lives lost, unnecessarily. Our research is dedicated to those who lost their lives in this tragedy and other mass casualty events. We can do better."

National health leadership organizations, such as the U.S. Centers for Medicare and Medicaid Services, the Assistant Secretary for Preparedness and Response, the Joint Commission, and the American Medical Association, as well as state and local emergency planners, could all potentially benefit from the use of HMSPI scores, according to Dr. Marcozzi. The tool could be used to support data-driven policy development and resource allocation to close gaps and assure that individuals get the care they need, when then need it, during a crisis.

Ricardo Pietrobon, MD, PhD, MBA, Adjunct Associate Professor of Emergency Medicine at UMSOM, Nicole Baehr, Manager of Operations at UMMC, and Brian J. Browne, MD, Professor and Chair of the Department of Emergency Medicine, were co-authors on this study. Researchers from the University of Nebraska Medical Center, University of Miami, and the U.S. Department of Veterans Affairs also participated in this research. The study was funded by the Bipartisan Commission on Biodefense.

"The COVID-19 pandemic taught us that we need to be better prepared for the unexpected crisis," said E. Albert Reece, MD, PhD, MBA, Executive Vice President for Medical Affairs, UM Baltimore, and the John Z. and Akiko K. Bowers Distinguished Professor and Dean, University of Maryland School of Medicine. "Having an important metric like the HMSPI could be a game changer that ultimately saves lives during a surge by helping hospitals identify and fix their vulnerabilities.

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JUL 7, 2021

 

Wolff Responds: Surfside Condo Collapse & Socialism

In this Wolff Responds, In this Wolff Responds, Prof. Wolff comments on the recent condominium building collapse in Miami. Housing, he argues, is a social responsibility and therefore decisions like construction, structural improvements and maintenance of residential buildings should be made by the society at large, instead of a small minority, like a coop board, as was the case with the Surfside condo.

Wolff Responds is a @Democracy At Work  production. We provide these videos free of ads. Please consider supporting our work. Visit our website democracyatwork.info/donate or join our growing Patreon community and support Global Capitalism Live Economic Update with Richard D. Wolff at https://www.patreon.com/gcleu.

 

Experimental Investigation on Performance and Exhaust Emissions of a Diesel Engine Fueled With Palm Oil Shea Butter Oil Blends Biodiesels

International Journal of Trend in Scientific Research and Development - IJTSRD

2021, International Journal of Trend in Scientific Research and Development

1 View7 Pages

1 File ▾

Biodiesel,

Engine Performance,

Transesterification

In this study, experimental investigations on the performance and exhaust emissions of a diesel engine was carried out using Palm oil Shea butter oil biodiesel as fuel. The two vegetable oils, Shea butter SB and Palm oil PO were blended in the proportion 25 75 , 50 50 , and 75 25 v v. The transesterification of the blended oils were carried out using ethanol, with potassium hydroxide as catalyst. The chemo physical properties of the biodiesels produced were determined experimentally and compared with that of petroleum diesel. Engine performance and emission test were conducted using the engine test bed with the instrumentation unit, emission gas analyzer, and the produced biodiesels as fuel. From the results, it was observed that, the petroleum diesel recorded the highest torque, while biodiesels recorded reduced values of torque at all the loads with the 100 SB and 75 SB 25 PO biodiesels both recorded the same values of torque at all the loads. The 100 SB biodiesel recorded the highest exhaust temperature, while the petroleum diesel recorded the lowest exhaust temperature at all the loads. Exhaust gas temperature increase as the load increases. Biodiesels showed reduced brake power as compared to petroleum diesel, but the 100 SB and 75 SB 25 PO both recorded the highest brake power among the biodiesels at all the loads. Biodiesels recorded higher values of BSFC as compared to petroleum diesel, with the 25 SB 75 PO biodiesel having the highest BSFC at all the loads. The brake thermal efficiency BTE of the petroleum diesel was highest as compared to biodiesels at all the loads. The 25 SB 75 PO and 100 PO biodiesels both recorded the least carbon monoxide CO emissions, and CO emissions decreases with increase in loads. The petroleum diesel recorded the highest CO emissions for all the three loads. The carbon dioxide CO2 emissions increases with increase in loads, with the petroleum diesel recording the least CO2 emissions at all the loads. The petroleum diesel showed increased hydrocarbon HC emissions for all the loads, while the 25 SB 75 PO and 100 PO biodiesels recorded the least HC emission. The 100 SB biodiesel recorded the highest NOx emissions, while the petroleum diesel recorded the least NOx emissions at all the loads. Thus, the 25 SB 75 PO and 75 SB 25 PO with improved engine performance and reduced emissions is suitable for use in diesel engine without engine modification. Abdul Musa | L. T. Tuleun | J. S. Ib … View full abstract

https://www.academia.edu/49594985/Experimental_Investigation_on_Performance_and_Exhaust_Emissions_of_a_Diesel_Engine_Fueled_With_Palm_Oil_Shea_Butter_Oil_Blends_Biodiesels?email_work_card=view-paper

 

More EVs could reduce CO2 emissions in Hawaii by 93% in less than 30 years

UNIVERSITY OF HAWAII AT MANOA

Research News

 

IMAGE: ELECTRIC VEHICLES AT CHARGING STATIONS. view more 

CREDIT: PLUG'N DRIVE (DERIVATIVE WORK: MARIORDO), CC-BY-SA-2.0

By 2050, faster adoption of electric vehicles (EVs) and faster generation of renewable energy will result in 99% less fossil fuel consumed and 93% less CO2 emissions from passenger and freight vehicles on O?ahu. That's under the most ambitious scenario in an article published in World Electric Vehicle Journal, by University of Hawai?i at Mānoa School of Ocean and Earth Science and Technology (SOEST) faculty member Katherine McKenzie.

McKenzie, based at the Hawai?i Natural Energy Institute in SOEST, created mathematical models of four scenarios based on projections for the switch to electric passenger and freight vehicles, and renewable power generation. She quantified the impacts of fossil fuel use and CO2 emissions on O?ahu and found that scenarios with a slower transition to EVs result in billions more gallons of gasoline consumed, and tens of millions more tons of CO2 emitted.

As with many other remote communities still dependent on oil for both transportation and power, there remains a lack of critical analysis to determine the benefits of transitioning from internal combustion engine vehicles to plug-in electric vehicles (EVs). In 2020, average passenger EVs were found to consume the equivalent of 66 gallons of gasoline, seven times less fossil fuel than their gasoline-powered counterparts, which used 455 gallons. Average EVs also cut emissions in half, two metric tons of CO2 versus four metric tons of CO2.

"Continuing to purchase anything powered by petroleum locks in emissions and energy insecurity for years to come, at a time when decarbonization is a climate imperative," said McKenzie. "A shift is needed to energy efficient modes of travel--such as bicycling, walking and transit, along with reducing vehicle miles traveled (by "smart" city planning and remote work for example)."

CAPTION

CO2 emissions decrease dramatically as electric vehicles and renewable energy are adopted.

CREDIT

McKenzie (2021)

 

Human-driven habitat change leads to physical, behavioral change in mosquitofish

NORTH CAROLINA STATE UNIVERSITY

Research News

Bahamian mosquitofish in habitats fragmented by human activity are more willing to explore their environment, more stressed by change and have smaller brain regions associated with fear response than mosquitofish from unaffected habitats. The new study from North Carolina State University shows that these fish have adapted quickly in specific ways to human-driven change, and cautions that environmental restoration projects should understand these changes so as not to damage adapted populations.

The Bahamas mosquitofish is a small, coastal fish species that frequently inhabits tidal creeks - shallow, tidally influenced marine ecosystems. In the 1960s and 70s, road construction in The Bahamas caused many of these habitats to become "fragmented," or largely cut off from the ocean.

"Mosquitofish in these fragmented areas suddenly found themselves in a much different environment than previously, in terms of things like predation and tidal dynamics," says Brian Langerhans, associate professor of biology at NC State and corresponding author of the study. "We set out to determine how natural variation in structural habitat complexity and human-induced fragmentation influenced exploratory behavior, stress response, and brain anatomy."

Langerhans and a team of NC State researchers observed about 350 mosquitofish from seven different populations: three fragmented and four non-fragmented. The habitats varied in complexity, from simple mud-bottomed spaces to those that included a large number of rocks and vegetation, such as mangroves.

"We were testing predictions based upon our understanding of natural selection," Langerhans says. "For instance, in a fragmented space with fewer natural predators, we hypothesized that those fish would be more exploratory, since exploratory behavior could be rewarded in terms of competing for food. We also wanted to see if there were physiological changes to the areas of the brain that are associated with those and other similar behaviors."

The team measured stress response and exploratory behavior by temporarily placing mosquitofish in a different environment and observing changes in respiration and their willingness to explore. They also compared brain size in fish from the different habitats.

They found that overall, fish from a more complex environmental habitat were more willing to explore new environments. But for a given level of habitat complexity, fish in fragmented sites were more exploratory than those from unfragmented sites. In addition, fish from fragmented habitats had a higher stress response to change.

"These findings were in line with our expectations," Langerhans says. "Exploratory behavior can reward fish in habitats with few predators by helping them compete for food, and can give fish in complex habitats an advantage in locating safety and hard-to-find food resources. As for the stress response, fish in unfragmented tidal creeks with lots of predators and high tidal dynamics have a higher level of everyday stress than those in more static, predator-free habitats. Change will be much more stressful for fish in the latter areas, since they're less stressed to begin with."

They also noted that while there were no overall differences in brain size between fish from differing habitats, fish from fragmented environments had a smaller telencephalon - the region of the brain associated with fear response, while fish in complex environments had a larger optic tectum and cerebellum, brain regions associated with responding to visual stimuli, motor skills, and associative learning.

"Brain tissue is expensive for an organism to produce," Langerhans says. "If fish in fragmented or simple environments no longer experience major demands for behaviors such as avoiding predation or navigating complex situations, seeing changes in these brain areas isn't that surprising."

The study also highlights how quickly organisms adapt to new environments, and how those environments affect the biological makeup of their inhabitants - something that restoration project planners should keep in mind when attempting to restore habitats to their ancestral state.

"Everything that humans plan to do to these environments should have a lot of forethought put into it," Langerhans says. "If local adaptations occurred over a 50-year period in response to an altered environment and we quickly restore it to 'normal,' you could do more harm than good to some of its inhabitants."

The research appears in the Journal of Animal Ecology, and was supported by NC State's W.M. Keck Center for Behavioral Biology, the Helge Axson Johnson Foundation, and the Swedish Research Council (Grant 2015-00300). NC State graduate student Matthew Jenkins is first author. NC State undergraduates John Cummings and Alex Cabe, fisheries and wildlife professor Nils Peterson, and former NC State postdoctoral researcher Kaj Hulthén, also contributed to the work.

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Note to editors: An abstract follows.

"Natural and anthropogenic sources of habitat variation influence exploration behaviour, stress response, and brain morphology in a coastal fish"

DOI: 10.1111/1365-2656.13557

Authors: Matthew R. Jenkins, John M. Cummings, Alex R. Cabe, Kaj Hulthén, M. Nils Peterson, R. Brian Langerhans, North Carolina State University

Published: Journal of Animal Ecology

Abstract: Evolutionary ecology aims to better understand how ecologically important traits respond to environmental heterogeneity. Environments vary both naturally and as a result of human activities, and investigations that simultaneously consider how natural and human-induced environmental variation affect diverse trait types grow increasingly important as human activities drive species endangerment. Here, we examine how habitat fragmentation and structural habitat complexity, affect disparate trait types in Bahamas mosquitofish (Gambusia hubbsi) inhabiting tidal creeks. We tested a priori predictions for how these factors might influence exploratory behaviour, stress reactivity, and brain anatomy. We examined approximately 350 adult Bahamas mosquitofish from seven tidal creek populations across Andros Island, The Bahamas that varied in both human-caused fragmentation (three fragmented, four unfragmented) and natural habitat complexity (e.g. 5-fold variation in rock habitat). Populations that had experienced severe human-induced fragmentation, and thus restriction of tidal exchange from the ocean, exhibited greater exploration of a novel environment, stronger physiological stress responses to a mildly stressful event, and smaller telencephala (relative to body size). These changes matched adaptive predictions based mostly on 1) reduced chronic predation risk and 2) decreased demands for navigating tidally dynamic habitats. Populations from sites with greater structural habitat complexity showed a higher propensity for exploration and a relatively larger optic tectum and cerebellum. These patterns matched adaptive predictions related to increased demands for navigating complex environments. Our findings demonstrate environmental variation, including recent anthropogenic impacts (<50 years), can significantly affect complex, ecologically important traits. Yet trait-specific patterns may not be easily predicted, as we found strong support for only six of 12 predictions. Our results further highlight the utility of simultaneously quantifying multiple environmental factors--e.g. had we failed to account for habitat complexity, we would not have detected effects of fragmentation on exploratory behaviours. These responses, and their ecological consequences, may be complex: rapid and adaptive phenotypic responses to anthropogenic impacts can facilitate persistence in human-altered environments, but may come at a cost of population vulnerability if ecological restoration were to occur without consideration of the altered traits.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of 

 

Wastewater did not significantly alter seismic stress direction in southern Kansas

SEISMOLOGICAL SOCIETY OF AMERICA

Research News

 

Although wastewater disposal has been the primary driving force behind increased earthquake activity in southern Kansas since 2013, a new study concludes that the disposal has not significantly changed the orientation of stress in the Earth's crust in the region.

Activities like wastewater disposal can alter pore pressure, shape and size within rock layers, in ways that cause nearby faults to fail during an earthquake. These effects are thought to be behind most recent induced earthquakes in the central and eastern United States.

It is possible, however, that human activity could also lead to earthquakes by altering the orientation of stresses that act on faults in the region, said U.S. Geological Survey seismologist Robert Skoumal, who co-authored the study in Seismological Research Letters with USGS seismologist Elizabeth Cochran.

"Since we do not see evidence for a significant stress rotation [in the region], we think most of the earthquakes in southern Kansas are due to changes in pore pressures or porelastic effects rather than due to stress rotations," Skoumal said.

One way that researchers can learn more about the orientation of the stress field in rock layers where fluid fills fractures in the rock is through a seismic wave effect called shear wave splitting. Some of the shear waves traveling through the rock move parallel to open fractures and are therefore faster, while others move perpendicular to the fractures and have a lower velocity. Estimating the direction of the fast waves can help determine the orientation of the stress field.

A previous shear wave splitting study in southern Kansas estimated a 90-degree rotation in the fast direction beginning in 2015, which the study authors attributed to elevated pore fluid pressures from wastewater disposal. However, the rotation coincided with a change in the stations used to observe the shear waves.

Skoumal and Cochran decided to take another look at stress changes in southern Kansas as part of a larger effort to characterize stress in rock reservoirs without drilling expensive boreholes. When they analyzed shear wave splitting using high-quality data collected from a stable local seismic network, they found that the regional stress orientation remained relatively constant between 2014 and 2017.

The geological conditions of a wastewater reservoir might affect whether injection can alter stress orientation, Skoumal noted. Most of the wastewater injected in southern Kansas went into rock layers called the Arbuckle Group, "which is underpressurized--fluid can be 'poured in' without the need of a pump," Skoumal said, noting that pore pressures can diffuse rapidly in the highly permeable rock.

There are no reports of significant stress rotations due to wastewater disposal, the authors note, suggesting that it may either not be a common occurrence, the stress rotations are smaller than can be detected with current methods, or that the phenomenon hasn't been studied enough. Until recently, seismic instrumentation has been sparse in many places that have experienced a large increase in wastewater disposal over the past decade.

"Documenting stress orientations is already challenging in these regions, and characterizing changes in those stresses over time is an even greater challenge," Skoumal said. "In the areas where we have looked though, we haven't seen compelling evidence for significant stress rotations due to wastewater disposal."

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Reducing the melting of the Greenland ice cap using solar geoengineering?

A study conducted by ULiège climatologists using the MAR climate model looks at the feasibility and impact of using such technologies

UNIVERSITY OF LIEGE

Research News

Injecting sulphur into the stratosphere to reduce solar radiation and stop the Greenland ice cap from melting. An interesting scenario, but not without risks. Climatologists from the University of Liège have looked into the matter and have tested one of the scenarios put forward using the MAR climate model developed at the University of Liège. The results are mixed and have been published in the journal The Cryosphere.

The Greenland ice sheet will lose mass at an accelerated rate throughout the 21st century, with a direct link between anthropogenic greenhouse gas emissions and the extent of Greenland's mass loss. To combat this phenomenon, and therefore global warming, it is essential to reduce our greenhouse gas emissions. Every day new ideas emerge to slow down global warming, such as the use of solar geoengineering, a climate intervention that consists of artificially reducing solar radiation above the ice caps and thus limiting the melting of the ice. How can this be done? The idea is to inject sulphur into the stratosphere, a stable meteorological zone located between 8 and 15 km above sea level in the atmosphere," explains Xavier Fettweis,climatologist and director of the Climatology Laboratory at ULiège. The sulphur will then act as a sort of mirror that will reflect part of the solar radiation back into space". An intervention which therefore makes it possible to reduce the amount of sunshine on earth, similar to what happens during volcanic eruptions. In 1991, the eruption of Pinatubo (Philippines) injected millions of tonnes of sulphur dioxide into the stratosphere, causing a drop in global temperatures of around 0.5°C. This observation led to the development of solar geoengineering scenarios. Are these scenarios really reliable and risk-free? This is what the ULiège climatologists wanted to test.

We used a plausible scenario of solar geoengineering (G6solar) that would reduce global warming by a factor of 2 on a global scale compared with the most pessimistic scenario in which nothing would be done about the climate," continues Xavier Fettweis. By forcing the MAR (Regional Atmospheric Model) developed at ULiège to use this scenario, we show that the reduction in solar radiation associated with this scenario would make it possible to locally reduce the melting at the surface of the Greenland ice sheet by 6% in addition to the global reduction in global warming. While these results seem encouraging, the researchers insist that this type of scenario would not be sufficient to maintain the ice cap in a stable state by the end of this century. Moreover, this type of intervention is not without risk since it could have a significant impact on the ozone layer and on water cycles and precipitation, accentuating the disparities between wet and dry regions. Only solar geoengineering scenarios, which are much more ambitious but becoming unrealistic and dangerous, would make it possible to save the cap," concludes Xavier Fettweis. We are talking here about human and intentional intervention in the climate. A plan B that is not! It is therefore urgent to drastically reduce our greenhouse gas emissions by means that we know but are struggling to implement.

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