Deeper understanding of the icy depths

Frazil ice formed below the ocean surface drives the generation of cold dense water.
Photo credit: Masato Ito

Scientists have uncovered new details of how ice forming below the ocean surface in Antarctica provides cold dense water that sinks to the seabed in an important aspect of global water circulation.

The results, published in the journal Science Advances, come from a team at the Hokkaido University’s Institute of Low Temperature Science, its Arctic Research Center, and the Faculty of Fisheries science, working with scientists at Japan’s National Institute of Polar Research and Aerospace Exploration Agency.

The seas around Antarctica, where a large amount of sea ice is formed, are central to global ocean water circulation, linking the Atlantic, Pacific, and Indian oceans. When sea ice is formed, it rejects salt, therefore leaving dense, cold water that sinks to the seabed. This water, called Antarctic Bottom Water (AABW), is the coldest and densest water mass in the global circulation, flooding across most of the deep seafloor known as the global abyss. Since the global ocean circulation influences the global climate, it is important to understand the mechanism of AABW formation and how the formation will be impacted by global warming.

Electroshock Therapy More Successful for Depression than Ketamine

Electroconvulsive therapy, often viewed with skepticism by members of the public, outperforms the drug ketamine in treating depression, according to a new report.
Credit: Tiago Bandeira

An analysis of six studies found that electroconvulsive therapy (ECT) is better at quickly relieving major depression than ketamine, a team of researchers report in JAMA Psychiatry on October 19.

Depression is a common illness affecting about 5% of adults worldwide, according to the World Health Organization (WHO). Feeling sad, irritable, losing pleasure in activities that used to be enjoyable, and sometimes experiencing unexplained pain or fatigue for weeks at a time are all symptoms of depression. Most people diagnosed with depression are offered an oral antidepressant (in combination with psychotherapy) as a first-line treatment option. But if oral antidepressants don’t help, or if the person is at imminent risk of hurting themselves, there are other, more rapid treatment options: ECT, and more recently ketamine or esketamine.

Esketamine, a nasal spray approved by the Food and Drug Administration to treat depression, is more commonly used in the US than ketamine. But there are no studies comparing esketamine’s effectiveness with ECT. There are studies done with ketamine, a sister drug to esketamine. Ketamine is commonly used in medicine as an injected anesthetic but has recently been tested as a fast-acting intervention to help people with major depression.

Converting Carbon Dioxide to Minerals Underground

Mineralizing carbon dioxide underground is a potential carbon storage method.
Credit: Illustration by Cortland Johnson | Pacific Northwest National Laboratory

A new high-profile scientific review article in Nature Reviews Chemistry discusses how carbon dioxide (CO2) converts from a gas to a solid in ultrathin films of water on underground rock surfaces. These solid minerals, known as carbonates, are both stable and common.

“As global temperatures increase, so does the urgency to find ways to store carbon,” said Pacific Northwest National Laboratory (PNNL) Lab Fellow and coauthor Kevin Rosso. “By taking a critical look at our current understanding of carbon mineralization processes, we can find the essential-to-solve gaps for the next decade of work.”

Mineralization underground represents one way to keep CO2 locked away, unable to escape back into the air. But researchers first need to know how it happens before they can predict and control carbonate formation in realistic systems.

“Mitigating human emissions requires fundamental understanding how to store carbon,” said PNNL chemist Quin Miller, co-lead author of the scientific review featured on the journal cover. “There is a pressing need to integrate simulations, theory, and experiments to explore mineral carbonation problems.”

Researchers discover new monster black hole 'practically in our back yard'

Dr. Sukanya Chakrabarti, the Pei-Ling Chan Endowed Chair in the Department of Physics & Astronomy, is the paper’s lead author. 
Credit: Michael Mercier / UAH

The discovery of a so-called monster black hole that has about 12 times the mass of the sun is detailed in a new Astrophysical Journal research submission, the lead author of which is Dr. Sukanya Chakrabarti, a physics professor at The University of Alabama in Huntsville (UAH).

“It is closer to the sun than any other known black hole, at a distance of 1,550 light years,” says Dr. Chakrabarti, the Pei-Ling Chan Endowed Chair in the Department of Physics at UAH, a part of the University of Alabama System. “So, it's practically in our backyard.”

Black holes are seen as exotic because, although their gravitational force is clearly felt by stars and other objects in their vicinity, no light can escape a black hole so they can’t be seen in the same way as visible stars.

“In some cases, like for supermassive black holes at the centers of galaxies, they can drive galaxy formation and evolution,” Dr. Chakrabarti says.

“It is not yet clear how these noninteracting black holes affect galactic dynamics in the Milky Way. If they are numerous, they may well affect the formation of our galaxy and its internal dynamics.”

Physicists confirm hitch in proton structure

The real photon that is produced in the virtual Compton scattering reaction provides electromagnetic perturbation to the proton and allows to measure its electromagnetic generalized polarizabilities.
Image credit: Courtesy of Nikos Sparveris, Temple University

Nuclear physicists have confirmed that the current description of proton structure isn’t all smooth sailing. A new precision measurement of the proton’s electric polarizability performed at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility has revealed a bump in the data in probes of the proton’s structure. Though widely thought to be a fluke when seen in earlier measurements, this new, more precise measurement has confirmed the presence of the anomaly and raises questions about its origin. The research has just been published in the journal Nature.

According to Ruonan Li, first author on the new paper and a graduate student at Temple University, measurements of the proton’s electric polarizability reveal how susceptible the proton is to deformation, or stretching, in an electric field. Like size or charge, electric polarizability is a fundamental property of proton structure.

What’s more, a precision determination of the proton’s electric polarizability can help bridge the different descriptions of the proton. Depending on how it is probed, a proton may appear as an opaque single particle or as a composite particle made of three quarks held together by the strong force.

Ecological imbalance: How plant diversity in Germany has changed in the past century

The cornflower is one of the "losers", its population has declined sharply over the past 100 years.
Photo Credit: André Künzelmann / UFZ

Germany's plant world has seen a greater number of losers than winners over the past one hundred years. While the frequencies and abundances of many species have shrunk, they have significantly increased in others. This has resulted in a very uneven distribution of gains and losses. It indicates an overall, large-scale loss of biodiversity, as a team lead by the Martin Luther University Halle-Wittenberg (MLU) and the German Centre for Integrative Biodiversity Research (iDiv) reports in the journal Nature.

It’s a weird paradox: While global biodiversity is lost at an alarming rate, at the local level, many studies are finding no significant decreases in animal and plant species numbers. "However, this doesn’t mean that the developments are not worrying," warns Professor Helge Bruelheide, an ecologist at MLU. After all, it also depends on which species we are talking about. For example, if survival artists that are specially adapted to peatlands or dry grasslands are displaced by common plants, the number of species often remains, in total, the same. However, diversity is still being lost because the once very distinct vegetation of different habitats is now becoming more and more similar.

To find out how strong this trend is in Germany, the team led by MLU looked at a multitude of local studies. Numerous experts provided data from more than 7,700 plots whose plant populations had been surveyed several times between 1927 and 2020. These studies, some of which have not been published before, cover a wide range of habitats and provide information on nearly 1,800 plant species. This includes about half of all the vascular plant species that grow in Germany. "Such time series can provide very valuable information," explains Dr Ute Jandt from MLU. This is because very precise botanical censuses can be conducted in plots that are often only ten or twenty square meters in size. ": It is highly unlikely that plants disappear or reappear unnoticed in such plots," Jandt adds.

Methane-Eating ‘Borgs’ Have Been Assimilating Earth’s Microbes

A digital illustration inspired by methane-eating archaea and the Borgs that assimilate them
Credit: Jenny Nuss/Berkeley Lab

In Star Trek, the Borg are a ruthless, hive-minded collective that assimilate other beings with the intent of taking over the galaxy. Here on nonfictional planet Earth, Borgs are DNA packages that could help humans fight climate change.

Last year, a team led by Jill Banfield discovered DNA structures within a methane-consuming microbe called Methanoperedens that appear to supercharge the organism’s metabolic rate. They named the genetic elements “Borgs” because the DNA within them contains genes assimilated from many organisms. In a study published today as the cover item in the journal Nature, the researchers describe the curious collection of genes within Borgs and begin to investigate the role these DNA packages play in environmental processes, such as carbon cycling.

First contact

Methanoperedens are a type of archaea (unicellular organisms that resemble bacteria but represent a distinct branch of life) that break down methane (CH4) in soils, groundwater, and the atmosphere to support cellular metabolism. Methanoperedens and other methane-consuming microbes live in diverse ecosystems around the world but are believed to be less common than microbes that use photosynthesis, oxygen, or fermentation for energy. Yet they play an outsized role in Earth system processes by removing methane – the most potent greenhouse gas – from the atmosphere. Methane traps 30 times more heat than carbon dioxide and is estimated to account for about 30 percent of human-driven global warming. The gas is emitted naturally through geological processes and by methane-generating archaea; however, industrial processes are releasing stored methane back into the atmosphere in worrying quantities.

Hands in people with diabetes more often affected by trigger finger

Mattias Rydberg, doctoral student at Lund University and resident physician at Skåne University Hospital
Source: Lund University

Locked fingers, known as trigger finger, are more common among people with diabetes than in the general population. A study led by Lund University in Sweden shows that the risk of being affected increases in the case of high blood sugar. The study has been published in Diabetes Care.

Trigger finger means that one or more fingers, often the ring finger or thumb, ends up in a bent position that is difficult to straighten out. It is due to the thickening of tendons, which bend the finger, and their connective tissue sheath, which means that the finger becomes fixed in a bent position towards the palm. It is a painful condition that can often be treated with cortisone injections, but sometimes requires surgery.

“At the hand surgery clinic, we have noted for a long time that people with diabetes, both type 1 and type 2, are more often affected by trigger finger. Over 20 percent of those who require surgery for this condition are patients who have, or will develop, diabetes,” says Mattias Rydberg, doctoral student at Lund University, resident physician at Skåne University Hospital and first author of the study.

To study whether high blood sugar (blood sugar dysregulation) increases the risk of trigger finger, the researchers examined two registers: Region Skåne’s healthcare database, which includes all diagnoses, and the Swedish national diabetes register. Between 1 and 1.5 per cent of the population are affected by trigger finger, but the diagnosis arises among 10-15 per cent of those who have diabetes, and the phenomenon appears most in the group with type 1 diabetes.

The Most Precise Accounting Yet of Dark Energy and Dark Matter

G299 was left over by a particular class of supernovas called Type Ia. 
Credit: NASA/CXC/U.Texas

 Astrophysicists have performed a powerful new analysis that places the most precise limits yet on the composition and evolution of the universe. With this analysis, dubbed Pantheon+, cosmologists find themselves at a crossroads.

Pantheon+ convincingly finds that the cosmos is composed of about two-thirds dark energy and one-third matter — mostly in the form of dark matter — and is expanding at an accelerating pace over the last several billion years. However, Pantheon+ also cements a major disagreement over the pace of that expansion that has yet to be solved.

By putting prevailing modern cosmological theories, known as the Standard Model of Cosmology, on even firmer evidentiary and statistical footing, Pantheon+ further closes the door on alternative frameworks accounting for dark energy and dark matter. Both are bedrocks of the Standard Model of Cosmology but have yet to be directly detected and rank among the model's biggest mysteries. Following through on the results of Pantheon+, researchers can now pursue more precise observational tests and hone explanations for the ostensible cosmos.

"With these Pantheon+ results, we are able to put the most precise constraints on the dynamics and history of the universe to date," says Dillon Brout, an Einstein Fellow at the Center for Astrophysics | Harvard & Smithsonian. "We've combed over the data and can now say with more confidence than ever before how the universe has evolved over the eons and that the current best theories for dark energy and dark matter hold strong."

Forgetting is natural, but learning how to learn can slow it down

Students studying at Iowa State University.
Credit: Christopher Gannon/Iowa State University

Whether you’re trying to ace a test or pick up a new hobby, Iowa State Psychology Professor Shana Carpenter says combining two strategies – spacing and retrieval practice – is key to success.

Carpenter is the lead author of a paper in Nature Reviews Psychology that examined more than 100 years of research on learning.

“The benefits of spacing and retrieval practice have been confirmed over and over in studies in labs, classrooms, workplaces, but the reason why we’re showcasing this research is because these two techniques haven’t fully caught on. If they were utilized all the time, we’d see drastic increases in learning,” said Carpenter.

In the paper, Carpenter and her co-authors describe spacing as a strategy to learn in small doses over time. It’s the opposite of cramming the night before an exam. In one study, medical students who received repeated surgery training over three weeks performed better and faster on tests 2 weeks and 1 year later compared to medical students who had the same training all on one day.

Carpenter says there isn’t a universal rule about how much time to schedule between practice sessions. But research shows returning to the material after forgetting some – but not all – of the content is effective.