New research confirms that the universe is expanding too fast, beyond theoretical limits; sleeping pills interfere with the brain's waste removal | Technology Weekly

Compiled by Zhou Shuyi and Pingsheng

First recorded chirping 'space chorus'

What kind of sound will be produced when the Earth's magnetic field lines are "plucked" by charged particles in space like strings? A study published in Nature on January 23 recorded the world's first distant "space chorus". Cao Jinbin, the corresponding author of the paper and an academician of the Chinese Academy of Sciences, said that this work broke the traditional view of the international scientific community on the generation and propagation mechanism of chorus waves that has lasted for more than 70 years, and discovered a new mechanism for the generation of chorus waves - nonlinear wave-particle interaction.

The magnetic field lines of the Earth's magnetic field are like "strings" with both ends fixed at the Earth's north and south magnetic poles. When the solar wind energy enters the Earth's magnetosphere and "plucks" these strings through related physical processes, it will excite electromagnetic waves with frequency characteristics similar to the chorus of birds in the early morning, which are called chorus waves in the scientific community. Chorus waves are one of the strongest electromagnetic fluctuations in the plasma of the Earth and planetary space. In the past, it was generally believed that they only appeared in the dipole magnetic field area close to the Earth.

The researchers analyzed the massive data collected by the International Magnetosphere Multiscale Satellite (MMS) over the years and discovered for the first time the continuous occurrence of acoustic waves in the neutral sheet region of the magnetotail, which is 165,000 kilometers away from the Earth and has a non-dipole field structure. The magnetic field in the neutral sheet region of the magnetotail is extremely weak, only one ten-thousandth of the magnetic field on the surface of the Earth, and its topological structure is completely different from the dipole field. In the framework of traditional acoustic wave theory, acoustic waves should not exist there. The study also gave a theoretical explanation, believing that nonlinear wave-particle interaction is the cause of this acoustic wave.

"We observed that the frequency of the chorus is less than 100 Hz, which is within the frequency range of sound waves that humans can hear. After converting it into audio output, we get a 'space chorus' that we can hear," said Liu Chengming, the first author of the paper and an associate professor at the Beihang University. "This sound not only sounds like birds singing, but also a bit like the space whale song in science fiction works."

The combined acoustic wave plays a key role in the acceleration of high-energy electrons in the Earth's radiation belt and the generation of polar pulsed auroras. It accelerates low-energy electrons into high-energy electrons (million electron volts, MeV), endangering the stable operation of spacecraft and the health and safety of astronauts; it can also scatter electrons and make them settle along the magnetic field lines of the Earth's magnetic field into the upper atmosphere of the polar regions, thereby forming spectacular and beautiful pulsating auroras; the combined acoustic wave can also induce hissing waves, change the structure of the high-energy electron radiation belt in near-Earth space, modulate the magnetosphere-ionosphere coupling, and thus affect space weather changes.

"Magic weight loss drug" increases risk of pancreatitis by 146%

Use of glucagon-like peptide 1 receptor agonists (GLP-1RAs) may be associated with a range of health effects, including decreased risks for 42 health conditions and increased risks for 19, according to an observational study of 2.4 million participants published January 20 in Nature Medicine.

GLP-1RA, as a new class of glucose-lowering drugs, has become popular in the past few years due to its significant weight loss effect. Researchers analyzed data from the U.S. Department of Veterans Affairs to study the relationship between the use of GLP-1RA (mainly semaglutide) and 175 health outcomes in 215,970 diabetic patients. The authors compared them with a control group using non-GLP-1RA glucose-lowering drugs.

The results showed that participants using GLP-1RA had a lower risk of coagulation and cardiometabolic diseases (such as deep vein thrombosis, pulmonary embolism, stroke, cardiac arrest, heart failure, and myocardial infarction). The study also found other potential beneficial effects beyond the previously recognized benefits, including associations with lower risks of substance abuse, mental illness, epilepsy, bacterial infection, and pneumonia. GLP-1RA users had an 18% lower risk of mental illness, a 12% lower risk of Alzheimer's disease, and a 13% lower risk of addiction disorders. At the same time, the use of GLP-1RA was also associated with gastrointestinal diseases (such as nausea and vomiting, diverticulitis, gastritis, and abdominal pain), as well as an increased risk of hypotension, syncope, and arthritis. GLP-1RA users had an 11% increased risk of arthritis and a 146% increased risk of pancreatitis.

The authors note that their findings are observational and cannot indicate cause and effect. They believe that these findings help describe the broad health effects of GLP-1RAs, but further research in other cohorts and clinical trials is needed to confirm the results.

Brain-computer interface lets paralyzed man play games

In a study published in Nature Medicine on January 20, researchers developed a new brain-computer interface that can continuously detect and decode the finger movement intentions of paralyzed patients after surgical implantation, and even allow patients to "play video games" with their hands.

More than 5 million people in the United States have severe motor disabilities. Paralysis not only limits physical movement, but also damages the patient's mental health. A previous survey found that more than half of spinal cord injury paralysis patients have unmet needs in social, leisure and sports. Brain-computer interfaces, as an intervention, may help patients restore motor function. However, this technology currently has difficulty processing single finger movements and cannot perform complex movements such as typing, playing musical instruments or using game controllers.

New research has developed a new type of brain-computer interface that can continuously record the electrical activity patterns of brain neurons to translate complex movements. The interface was implanted in the left precentral gyrus of a quadriplegic patient, a brain area responsible for hand movement control. The researchers first asked the patient to observe a virtual hand making various movements while recording its neural activity, and then used a machine learning algorithm to identify signals related to specific finger movements. Using these signals, the system can accurately predict finger movements, allowing patients to control three sets of virtual fingers (thumb, index and middle fingers, ring finger and little finger), of which the thumb can manipulate activities in two dimensions. The system achieves unprecedented control accuracy and freedom.

The patient then used the brain-computer interface to control the speed and direction of a quadcopter in a video game and navigate various obstacle courses. Jaimie Henderson, one of the authors of the paper and a professor of neurosurgery at Stanford University, said: "People often focus on the recovery of basic functions - eating, dressing, and moving - these are all important. But many times, other equally important aspects of life are overlooked, such as entertainment and socializing with peers." He said that controlling virtual fingers through a brain-computer interface can realize many possibilities, such as operating CAD software and composing music.

Global life expectancy is expected to increase by 4.6 years in 2050, with a higher increase for men than for women

According to a global disease burden study by The Lancet, life expectancy is expected to continue to increase from 73.6 years in 2022 to 78.2 years in 2050, an increase of 4.6 years. The increase in male life expectancy is expected to be higher than that of female life expectancy: male life expectancy will increase from 71.1 years to 76.0 years, an increase of 4.9 years; female life expectancy will increase from 76.2 years to 80.5 years, an increase of 4.2 years.

The projections are based on the Reference Scenario (the most likely future). Global life expectancy is projected to increase more slowly between 2022 and 2050 than it did in the three decades before the COVID-19 pandemic (2020). Globally, improvements in life expectancy and age-standardized disease burden are projected between 2022 and 2050, with much of the burden continuing to shift from communicable, maternal, neonatal and nutritional diseases to chronic noncommunicable diseases, with the most pronounced shift occurring in sub-Saharan Africa and South Asia. This shift is reflected in the leading global causes of disability-adjusted life years (DALYs, the total number of healthy years lost from morbidity to death, often used to measure the burden of disease), with ischemic heart disease, neonatal disorders, stroke and lower respiratory tract infections topping the list in 2022, while the top four causes in 2050 are ischemic heart disease, stroke, diabetes and chronic obstructive pulmonary disease. In addition, deaths and DALYs from all causes will generally increase due to population growth and aging.

New research confirms that the universe is expanding too fast, beyond the limits of existing theories

A study published on January 15 in The Astrophysical Journal Letters confirms that the universe is expanding faster than theoretical models predict and beyond the speed that current physics can explain. "The tension has now become a crisis," said Dan Scolnic, the author of the study.

The Hubble constant quantitatively describes the current expansion rate of the universe. Since Edwin Hubble first discovered the expansion of the universe in 1929, accurately determining the Hubble constant has been an important issue in modern cosmology. In recent years, there has been an increasingly serious deviation between the local direct measurement value of the Hubble constant and the global model fitting value. This deviation is called the "Hubble tension". Among them, the local direct measurement value comes from the local distance ladder measurement results of the late universe, while the global model fitting value comes from the observational constraints of the microwave background radiation of the early universe on the standard model of cosmology. If the deviation is not caused by the observational error and systematic error of any of the observation methods, then it is very likely that there is new physics beyond the standard model of cosmology.

Precise measurement of the distance between Earth and the Coma Cluster of galaxies provides new evidence for the Hubble tension. | NOIRLab

The intensity of light decays in inverse proportion to the square of the distance it propagates. Using the distance ladder method, the research team monitored the light curves of 12 Type Ia supernova remnants in the Coma Cluster during their explosions and measured that the Coma Cluster is about 320 million light-years away from Earth, almost in the center of the range of measurements over the past 40 years, showing a high degree of accuracy. Based on this high-precision measurement, the researchers calibrated the rest of the distance ladder step by step and derived the Hubble constant to be 76.5 km/(s·Mpc). This means that for every 3.26 million light-years increase in the measured local universe distance, the recession velocity increases by 76.5 km/s.

This result is consistent with other local direct measurements of the Hubble constant, but conflicts with the global model fit. The new study strongly supports the view that the Hubble tension is not caused by measurement errors, but rather by defects in existing models.

Scolnic said that over the past decade, the astronomical community has repeatedly analyzed data and the Hubble constant obtained has always been inconsistent with the prediction of the standard model. "For me, the new study is the best confirmation so far. ... We are working hard to overturn the model that has been used for 25 years, which may reshape our view of the universe."

Sleeping pills interfere with the brain's waste removal

A good night's sleep makes people clear-headed. An international team recently published a paper in Cell, saying that when mice are in deep sleep, a substance called norepinephrine plays a key role in the process of "washing out" waste in their brains.

Researchers from the University of Copenhagen in Denmark, the University of Oxford in the UK and other institutions found that when mice are in deep sleep, the brain stem releases a wave of norepinephrine approximately every 50 seconds, triggering vasoconstriction and causing the surrounding cerebrospinal fluid to flow rhythmically, carrying away waste.

Experiments on mice also showed that sleeping aids such as sleeping pills may disrupt this mechanism. They gave mice the commonly used sleeping pill zolpidem and found that although the mice taking sleeping pills fell asleep faster, the level of norepinephrine released through the above mechanism during deep sleep was 50% lower than that of mice that fell asleep naturally, and the amount of fluid transport into the brain decreased by more than 30%.

The research team said that the relevant physiological structure of the human brain is similar to that of mice, but further research is needed to confirm whether this mechanism also exists. In the long run, taking sleep-aiding drugs may affect cognitive function, so it is very important to obtain long-term restorative sleep in an appropriate way. (Xinhua News Agency)

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