Dolphins seem to adjust their heart rates as they dive to avoid decompression sickness, also known as the bends, which is caused by sudden changes in pressure.
Human divers must avoid surfacing too quickly as the drop in pressure can force nitrogen bubbles into their airways and cause joint pain or even paralysis.
It was thought that marine mammals such as dolphins didn’t have this problem, says Andreas Fahlman at the Oceanographic Foundation in Valencia, Spain, but researchers have recently been reassessing this idea.
To test it, Fahlman and his colleagues trained captive bottlenose dolphins to take short or long dives on command. They measured the animals’ heart rates using electrocardiography and found that they slow their hearts just before diving underwater.
When preparing for a long dive, the dolphins reduced their heart rate more quickly and to a lower rate than when they were about to take a shorter dive. This conserves more oxygen and reduces decompression sickness by limiting nitrogen intake.
Fahlman says this is probably a conscious rather than automatic response: the dolphins are controlling their heart rate by deflating part of their lungs to let blood or air flow to areas under pressure. “They are controlling how much blood is sent to the lungs and where in the lungs it’s sent to avoid nitrogen uptake,” he says. “They can basically step on and off the gas pedal when they want to.”
Stress from noises like sonar or machinery used for oil exploration may interfere with this conscious control of heart rate, says Fahlman, possibly increasing the chances of a dolphin getting the bends. By learning more about dolphins’ physiology, we might be able to find ways to mitigate these problems, he says.
A huge cache of fresh water found beneath the sea floor off the western coast of Hawaii’s Big Island could lift the threat of drought for people living there.
Eric Attias at the University of Hawaii and his colleagues discovered the reservoir, which is contained in porous rock reaching at least 500 metres beneath the sea floor, using an imaging technique similar to an MRI scan.
They used a boat towing a 40-metre-long antenna behind it to generate an electromagnetic field, sending an electric current through the sea and below the sea floor. As seawater is a better conductor than fresh water, the team could distinguish between the two. They found that the reservoir extends at least 4 kilometres from the coast and contains 3.5 cubic kilometres of fresh water.
Most of Hawaii’s fresh water comes from onshore aquifers, which are layers of rock and soil underground that collect water after rainfall. The team believes that this newfound reservoir is replenished by water flowing out of these aquifers.
Climate change has lead to increasing droughts in many places, which could leave some areas without water. In Hawaii, decreased rainfall and the destruction of forests could mean the onshore aquifers eventually dry up.
Not only would the offshore reservoir help relieve drought, it may also be easier to pump from than the onshore aquifers, because the water is under high pressure. Accessing it would also have minimal impact on surrounding ecosystems, says Attias.
Similar caches of water may be located off other volcanic islands, says the team, which could provide a relief for other places threatened by water scarcity due to climate change.
Drinking cocoa may give your brain a major boost of speed and accuracy, according to new research from the University of Birmingham. Study participants who drank cocoa with high levels of flavanols were able to complete complex cognitive tasks much more efficiently.
Flavanols are plant nutrients that are found in tea, grapes, tomatoes, and many other foods, but they are particularly concentrated in the cacao beans that are used to make cocoa. Previous studies have shown that cocoa flavanols can help lower blood pressure, improve blood circulation, and fight cell damage.
The Birmingham team set out to investigate the cognitive effects of cocoa flavanols in young, healthy individuals while focusing on a link between blood oxygenation and cognitive benefits. The researchers used non-invasive brain imaging to measure blood oxygenation levels among individuals who consumed cocoa that contained either high levels of flavanols or no flavanols.
In collaboration with scientists at the University of Illinois, the experts showed that participants who consumed a flavanol-rich drink produced a faster and greater increase in blood oxygenation levels in response to artificially elevated levels of CO2.
Approximately two hours after drinking the cocoa, the volunteers were exposed to air with 5 percent carbon dioxide, which is about 100 times the normal concentration. This is a standard method for challenging brain vasculature to determine how well it responds, said study co-author Professor Gabriele Gratton. He explained that the body typically reacts by increasing blood flow to the brain. “This brings in more oxygen and also allows the brain to eliminate more carbon dioxide.”
The researchers found that most of the individuals had a stronger and faster brain oxygenation response after the consumption of cocoa flavanols. “The levels of maximal oxygenation were more than three times higher in the high-flavanol cocoa versus the low-flavanol cocoa, and the oxygenation response was about one minute faster,” said study lead author Dr. Catarina Rendeiro.
After the carbon dioxide test, the participants were assigned progressively complex cognitive tests, which often required them to manage contradictory or competing demands. During the tests, the researchers found that volunteers who consumed flavanols executed tasks with significantly higher speed and accuracy.
“Our results showed a clear benefit for the participants taking the flavanol-enriched drink – but only when the task became sufficiently complicated,” said Dr. Rendeiro. “We can link this with our results on improved blood oxygenation – if you’re being challenged more, your brain needs improved blood oxygen levels to manage that challenge. It also further suggests that flavanols might be particularly beneficial during cognitively demanding tasks.”
The experts discovered that a small group of four volunteers did not benefit from the flavanol-enriched drink in terms of blood oxygenation levels, and also did not experience any cognitive benefits. These individuals had high levels of brain oxygenation responses at the beginning of the trial that were not influenced by the enriched cocoa.
“Because these four participants already had the highest oxygenation responses at baseline, this may indicate that those who are already quite fit have little room for improvement,” said Dr. Rendeiro. “Overall, the findings suggest that the improvements in vascular activity after exposure to flavanols are connected to the improvement in cognitive function.”
“We used cocoa in our experiment, but flavanols are extremely common in a wide range of fruit and vegetables. By better understanding the cognitive benefits of eating these food groups, as well as the wider cardiovascular benefits, we can offer improved guidance to people about how to make the most of their dietary choices.”
Earless moths have sound-absorbent wings that act as acoustic camouflage from preying bats. The moth wings have an ultrathin layer of scales that absorb sound and could be adapted for noise-cancelling technology.
Marc Holderied at the University of Bristol, UK, and his colleagues projected sound waves at the wings of two species of earless moths (Antheraea pernyi and Dactyloceras Lucina). They found that the sound waves that bounced back from the moth wings were much quieter.
By using an imaging technique called acoustic topography, the team found that these moth wings have a layer of scales that are arranged in a special repeating pattern that absorbs sound across a wide range of frequencies.
“Similar to how stealth bombers are less detectable by enemy radars, the moths have developed a stealth coating against the bat’s sonar,” says Holderied. The moth wings, which are around a tenth of a millimetre thick, absorb the specific sound waves produced by bats.
Bats interpret their surroundings using echolocation: they send out sound waves and when the sound hits an object, an echo is produced. The bats use these echoes to build an image of their environment. Because the earless moths’ wings absorb these sound waves, they remain largely undetected, improving their chances of survival.
Other moths have ultrasensitive ears to hear bats, but the deaf, earless moths rely on this sound-absorbent layer to evade their predators.
Holderied and his team also compared the earless moths with two species of butterflies and found that only the moths had the sound-absorbing quality.
Social isolation — something many people are experiencing during the COVID-19 pandemic — leaves people’s brains craving other people, showing that social aspects of a pandemic shouldn’t be ignored.
A hungry brain craves food. A lonely brain craves people. After spending a day completely isolated from anyone else, people’s brains perked up at the sight of social gatherings, like a hungry person’s brain seeing food, scientists report November 23 in Nature Neuroscience.
Cognitive neuroscientist Livia Tomova, then at MIT, and her colleagues had 40 participants fast for 10 hours. At the end of the day, certain nerve cells in the midbrain fired up in response to pictures of pizza and chocolate cake. Those neurons — in the substantia nigra pars compacta and ventral tegmental area — produce dopamine, a chemical messenger associated with reward (SN: 8/27/15).
On a different day, the same people underwent 10 hours of isolation (no friends, no Facebook and no Instagram). That evening, neurons in the same spot activated in response to pictures of people chatting or playing team sports. The more hunger or isolation the subject reported, the stronger the effect (SN: 10/4/17).
In people who reported that they were generally more lonely, the social responses were blunted. “We don’t really know what causes that,” Tomova says. “Maybe being isolated doesn’t really affect them as much, because it’s something that is not that different, perhaps, from their everyday life.”
The midbrain, which plays an important role in people’s motivation to seek food, friends, gambling or drugs, responds to food and social signals even when people aren’t hungry or lonely. After all, a person always could eat or hang out. But hunger and loneliness increased the reaction and made people’s responses specific to the thing they were missing.
The findings “speak to our current state,” says Tomova, now at the University of Cambridge. COVID-19 has left many more socially isolated, putting mental as well as physical health at stake (SN: 3/29/20) and leaving people with cravings for more than food. “It’s important to look at the social dimension of this kind of crisis.”
Treatment teams consisting of a dermatologist, medical-nutritional therapist, general practitioners can provide a holistic approach to acne treatment.
Acne in adolescents and young adults can significantly affect mood, personality, and self-esteem. The effect acne has on mental health suggests dermatologists should consider incorporating psychological assessments into the treatment of these patients, according to a review study published in the Journal of Cosmetic Dermatology.
Researchers from the United States, Romania, and Egypt conducted a review of research studies published from 2001 to 2020. Articles included in the review reported on acne and related psychological components.
The investigators of the review indicate that false myths and poor medical education influence acne’s evolution. Also, many patients with acne buy into “myths and misconceptions” regarding their disease and, as a consequence, many of these patients often seek medical attention at later disease stages.
Psychological impacts of acne that have been reported in the literature include stress, type D personality, social phobia disorder, anxiety, fear, depression, suicidal thoughts/attempts, social dysfunction, sexual dysfunction, and stigmatization. Patients with acne who also experience stress are more likely to pick at the skin, resulting in further inflammation, hyperpigmentation, and scarring. The release of neuropeptides associated with stress can also lead to cytokine production, which can further drive the inflammatory component of acne, the researchers noted.
Some studies have suggested that patients with severe acne have a higher rate of mental hospital admission for anxiety, adjustment disorders, personality disorders, and substance use disorders.
According to the investigators, clinicians should work toward better understanding of a patient’s feelings about how acne is effecting their personal and professional life. In addition, physicians should understand and consider the patient’s self-perception of acne severity.
Overall, the authors noted, clinicians should consider a holistic approach that focuses on how acne effects quality of life (QoL), relationships, and self-image. Psychological evaluation should be considered in conjunction with prescribing dermatological/cosmetic treatments to a patient with acne.
The authors of the review added that treatment teams consisting of a dermatologist, medical-nutritional therapist, general practitioners, “and plastic surgeons should increase therapy adherence and long-term effects on QoL and psychological impact of this disease.”
With COVID-19 infections spiking again at an alarming rate, Chicago is scrambling to catch up to other cities forecasting outbreaks by analyzing human waste flushed down thousands of toilets.
Signs of the novel coronavirus show up in sewers about a week before people surge into hospitals with symptoms of the disease, which during the past nine months has killed more than 1.3 million people worldwide, including 246,000 in the United States.
In an attempt to provide doctors and nurses with more time to prepare for outbreaks, a growing number of communities in the U.S. and other countries are collecting sewage samples and posting charts showing changes over time in the genetic signature of the SARS-CoV-2 virus.
“It’s much more efficient to test wastewater from a neighborhood, where a couple of samples could tell you as much as testing 500 people over and over again, said Sam Dorevitch, a University of Illinois at Chicago scientist involved in the project.
The Chicago research is part of a fast-growing effort to streamline methods used for decades to track disease and pollution. Sewage monitoring helped investigators trace a 2013 polio outbreak in Israel and, more recently, directed social services in a handful of American cities hit hard by the opioid epidemic.
New studies focused on the coronavirus are grounded in flat, scientifically acceptable jargon. But a sewage-testing company formed by researchers at the Massachusetts Institute of Technology is more direct, echoing potty-training books for toddlers.
“Everybody poops and pees every day,” Cambridge-based Biobot Analytics declares on its website. “This information is a readout of our health and well-being as a community.”
Based on interviews with a dozen scientists and government officials tracking the coronavirus, it appears one of the biggest challenges is determining where they should be collecting sewage.
Chicago’s labyrinth of sewers winds more than 4,500 miles under city streets. It is divided between the Chicago Department of Water Management and the Metropolitan Water Reclamation District, two agencies with a history of bureaucratic turf wars and a reputation for blaming each other when the system fails.
District officials are sending weekly samples from three treatment plants to researchers at Stanford and the University of Michigan. Those samples are being shared with the group from Illinois universities, which is using computer modeling to estimate where neighborhood-level sampling could identify virus hot spots.
“In other places they tracked the initial wave and how the lockdown reduced the SARS-CoV-2 signal in wastewater,” said Aaron Packman, a Northwestern University environmental engineer. “It picked back up again after states and cities relaxed their lockdowns.”
Boston and Tempe, Arizona, are two of the U.S. cities ahead of Chicago, largely because both had been studying opioids in sewage well before the pandemic began.
Pioneers also focused on how to inform the public about results and brainstormed how to debunk inevitable conspiracy theories.
“We stress that we aren’t testing down to the level of an individual homeowner,” said Rosa Inchausti, Tempe’s director of strategic management and diversity. “But when we detected a (coronavirus) spike in one of our neighborhoods, we told people they were at higher risk, flooded the area with masks and encouraged testing.”
Regular monitoring of Chicago sewage could help determine if person-to-person contact needs to be restricted in certain neighborhoods. After vaccines arrive, sewage tests could flag parts of the city lagging behind in inoculations.
Behind the scenes there is an intriguing competition among researchers and technology startups striving to discover quick, cutting-edge methods that can be easily replicated — a grail Packman described as more TikTok than MySpace.
The Chicago project, financed by a $1.25 million grant from the Skokie-based Walder Foundation, also includes researchers from the University of Chicago and the University of Illinois at Urbana-Champaign.
Another band of scientists led by Julius Lucks, a Northwestern chemistry and biological engineering professor, is perfecting a method that involves adding a few drops of sewage to a test tube containing a reagent for the coronavirus, potentially speeding up test results.
Biobot, the Massachusetts startup, conducts testing and compiles charts of the COVID-19 signature in Boston and more than a dozen other communities.
“One of the things the virus did to the country was to educate people about the potential of this technology to improve public health,” said Mariana Matus, the company’s co-founder and chief executive. “It could help policymakers decide if it is safe to send kids to school or open restaurants. In other words, when it is OK to resume a normal life.”
A new study finds similarities between the structures and processes of the human brain and the cosmic web. The research was carried out by an astrophysicist and a neurosurgeon. The two systems are vastly different in size but resemble each other in several key areas.
By Paul Ratner
Scientists found similarities in the workings of two systems completely different in scale – the network of neuronal cells in the human brain and the cosmic web of galaxies.
Researchers studied the two systems from a variety of angles, looking at structure, morphology, memory capacity, and other properties. Their quantitative analysis revealed that very dissimilar physical processes can create structures sharing levels of complexity and organization, even if they are varied in size by 27 orders of magnitude.
The unusual study was itself carried out by Italian specialists in two very different fields – astrophysicist Franco Vazza from the University of Bologna and neurosurgeon Alberto Feletti from the University of Verona.
“The tantalizing degree of similarity that our analysis exposes seems to suggest that the self-organization of both complex systems is likely being shaped by similar principles of network dynamics, despite the radically different scales and processes at play,” wrote the scientists in their new paper.
One of the most compelling insights of the study involved looking at the brain’s neuronal network as a universe in itself. This network contains about 69 billion neurons. If you’re keeping score, the observable universe has a web of at least 100 billion galaxies.
Another similarity is the defined nature of their networks–neurons and galaxies–that have nodes connected by filaments. By studying the average number of connections in each node and the clustering of connections in nodes, the researchers concluded that there were definite “agreement levels” in connectivity, suggesting the two networks grew as a result of similar physical principles, according to Feletti.
Section of the human brain (left) and a simulated section of the cosmos (right).Credit: University of Bologna
There are also interesting comparisons when it comes to the composition of each structure. About 77 percent of the brain is water, while about 70 percent of the Universe is filled with dark energy. These are both passive materials that have indirect roles in their respective structures.
On the flip side of that, about 30 percent of the masses of each system is comprised of galaxies or neurons.
The scientists also found an uncanny similarity between matter density fluctuations in brains and the cosmic web.
“We calculated the spectral density of both systems. This is a technique often employed in cosmology for studying the spatial distribution of galaxies,” Vazza said in a press release. “Our analysis showed that the distribution of the fluctuation within the cerebellum neuronal network on a scale from 1 micrometer to 0.1 millimeters follows the same progression of the distribution of matter in the cosmic web but, of course, on a larger scale that goes from 5 million to 500 million light-years.”
Check out the new study “The Quantitative Comparison Between the Neuronal Network and the Cosmic Web”, published in Frontiers in Physics.
Hallucinogenic mushrooms’ key ingredient, psilocybin, can swiftly and dramatically ease depression in the right therapeutic setting, a small study suggests.
A month after receiving two doses of the psychedelic drug, 13 people had big drops in depressive symptoms, researchers report November 4 in JAMA Psychiatry.
Because the study was small and lacked participant diversity, it’s unclear whether the positive results would extend to wider populations. Still, “the current results are clear,” says Jay Olson, a psychology researcher at Harvard University who wasn’t involved in the study. “At least for some people, psilocybin can reduce depression better than several common treatment options.”
Existing antidepressant drugs don’t work well for an estimated 30 to 50 percent of the people who try them; when they do work, the effects can take weeks to kick in. Psilocybin, a compound that can profoundly alter consciousness and perceptions of reality, might be a powerful alternative, says coauthor Roland Griffiths, a neuropsychopharmacologist at Johns Hopkins School of Medicine.
In the new study, patients with moderate or severe depression received two doses of psilocybin pills spaced about a week and a half apart. Participants also received therapy and support from researchers, before, during and after taking psilocybin.
A comparison group of 11 people waited eight weeks, then also received the two doses of psilocybin and supportive therapy. This delay allowed the researchers to look for improvements in symptoms that were not related to the drug.
Clinicians used a common depression rating scale consisting of 17 items to measure participants’ symptoms. Scores can range from 0 to 52, with higher numbers indicating more severe depression. Before receiving psilocybin, participants who got the drug without delay scored an average of 22.9 points, signaling the high end of moderate depression. Four weeks after the second dose, average scores dropped to 8.5. A score of 7 or below indicates no depression. Scores among the comparison group hovered around 23 while those people waited their turn to get the drug.
Overall, 13 of 24 people — including those who got psilocybin immediately and those who got it later — met the definition of remission four weeks after their respective treatments. The drops in depression symptoms are substantial compared with those found by some analyses of standard antidepressants, Griffiths says.
As with clinical studies in general, positive effects might arise simply from participants’ expectations, not the drug itself. But such effects are unlikely to account for the magnitude of the drop observed, Olson says.
The new findings on psilocybin’s antidepressant effects fit with earlier ones: A dose of the drug eased depression and anxiety in a small group of patients with cancer, effects that lasted for years in some cases, some of the same researchers reported in January (SN: 1/28/20). Another study, published in Lancet Psychiatry in 2016, found that signs of depression dropped in 12 people three months after two doses of psilocybin and psychological support.
Overall, the approach is promising, Griffiths says, but questions remain. “We still need to collect more safety data and we need to know conditions for optimal administration,” he says.
Moms already know that breast milk is ideal for a baby’s physical development. Now, research shows that being breastfed in infancy might even boost a child’s mental health, years later.
“Having identified that there are potential behavioral benefits, our study strengthens the case for public health strategies that promote breastfeeding, where possible,” study lead author Lydia Speyer, of the University of Edinburgh School of Philosophy, Psychology and Language Sciences, said in a university news release.
The new study included thousands of British children born between 2000 and 2002. They were assessed at ages 3, 5, 7, 11 and 14 using questionnaires about their strengths and difficulties, which had been completed by parents and teachers.
The results showed that kids who were breastfed for three months or more developed fewer behavioral difficulties than those who weren’t breastfed. They were also less likely to have social and emotional problems, such as anxiety, struggles forming friendships, or difficulties with concentration.
The findings held true even after the researchers accounted for other influencing factors, such as a mother’s education and mental health, and family wealth, according to the authors of the study. The results were published online Nov. 9 in the Archives of Disease in Childhood.
The investigators said their research is the first to track children’s behavior deep into adolescence and provides added proof of a link between breastfeeding and later behavioral development.
“The positive impact of breastfeeding on children’s physical development is well known, but the effect on their social and emotional development is less understood,” Speyer noted.
Dr. Jennifer Wu is an obstetrician-gynecologist at Lenox Hill Hospital, in New York City. She said that while the researchers couldn’t prove cause and effect, “the longevity of this study, and the fact that the behavioral analyses show the trend over time, make the data more robust.”
According to Wu, “breastfeeding can have far-reaching effects for the child,” and the findings from this new study “should be used in discussions with pregnant patients who are considering whether to breastfeed.”
But of course, society needs to make room so that new moms can freely breastfeed, as well, she said. “On a larger scale, workplaces need policies to support breastfeeding for 6 months,” Wu believes.
It's Interesting 