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Health

Get enough sleep or lose weight

At present, scientists believe that the main cause of obesity is increased calorie intake rather than lack of exercise. Previous studies have shown that lack of sleep affects appetite regulation, leading to an increase in food intake, which increases the risk of obesity. Getting enough sleep can help reduce calorie intake and reduce the risk of obesity, according to a study published in the Journal of Internal Medicine of the American Medical Association.

The researchers recruited 80 overweight adult volunteers who slept an average of less than 6.5 hours a night and were given personalized sleep improvement training. The researchers also used the double-labeled water method to track the changes in calorie intake of volunteers, that is, volunteers were asked to drink quantitative water labeled with deuterium heavy oxygen, and urine samples were collected continuously over a four-week experiment. energy consumption was calculated by measuring stable double-labeled isotopes and disappearance rates in urine samples. The results showed that when the volunteers increased their sleep time by 1.2 hours per night, their total calorie intake decreased by an average of 270 kcal per day. If you can maintain healthy sleep habits for a long time, you may lose 12 kilograms within three years, the researchers said.

Physics

Set a new record! The quantum state lasts for more than 5 seconds.

Recently, in a study published in the journal Progress of Science, researchers set a new record by reading qubits on demand and keeping the quantum state intact for more than five seconds. In this study, qubits are made of silicon carbide which is easy to obtain. For semiconductor qubits, the typical readout method is to use a laser to address qubits and measure the light reflected by them, but this process requires very effective detection of photons. Using a well-designed laser pulse, the researchers added a single electron to its qubit according to its initial quantum state (0 or 1).

With the help of a single readout method, scientists can also make the quantum state as long as possible, and in the past, quantum bits are easy to lose information because of noise in the environment. For this reason, the researchers prepared highly purified silicon carbide samples to reduce the background noise that would interfere with the qubit function, and then extended the preservation time of quantum information by applying a series of microwave pulses to the qubits. The researchers say five seconds is enough to send a light signal to the moon and return. Even after orbiting the earth nearly 40 times, this light can still correctly reflect the state of qubits, paving the way for the creation of a distributed quantum Internet. (science and Technology Daily)

Microbiology

The smallest propeller was found in the "fastest" creature.

Methanococcus Methanocaldococcus villosus is an archaea found near an undersea volcano in Iceland. It is only about 1 micron in size, but can swim at a speed of up to 500 body lengths per second. By contrast, cheetahs can only move 20 body lengths per second. If the methanococcus were as big as a cheetah, it would move at a speed of 3000 kilometers per hour. In a sense, this methanococcus is one of the fastest creatures on earth.

This methanococcus pushes itself through spiral fibers. In a study published yesterday in Nature Communications, scientists used cryogenic electron microscopes to study the structure of the world's smallest propeller at the atomic level. They found that the fiber is made up of thousands of two proteins alternately, which is more complex than our previous understanding of the structure of archaea. The researchers suggest that it is possible to develop a miniature drug delivery robot based on this miniature propeller in the future.

Health

97% of children have nicotine residue on their hands.

The smoke residue when smoking will adhere to the surface of clothes, walls, furniture and other objects, which is called "third-hand smoke". In the past, the effects of third-hand smoke were often limited to specific scenes such as in a room or in a car. Recently, a novel study published in JAMA Network Open extensively investigated the exposure of children to third-hand smoke.

Medical science

For the first time! Spinal cord implants can treat paralyzed mice with a success rate of up to 80%.

At present, millions of people around the world are paralyzed by spinal cord injury, and there is no effective treatment. Recently, in a new study published in Advanced Science, scientists at Tel Aviv University in Israel created for the first time a 3D-printed, new type of human spinal cord implant that can restore the walking ability of mice that have been paralyzed for a long time in the experiment. the success rate is as high as 80%.

Physics

Chinese scientists have observed the critical divergence of entropy waves in Fermi superflow for the first time.

More than 80 years ago, Landau established the two-fluid theory and predicted that entropy or temperature would propagate in superfluids in the form of waves, which he named the second sound (second sound). This phenomenon only occurs in superfluid, which is a macroscopic quantum phenomenon. The second sound transfer of transentropy wave has been observed in liquid helium and supercooled atomic systems before, but the dynamic process of the transfer has not been measured.

In cooperation with the Australian research team, Academician Pan Jianwei of the Chinese University of Science and Technology observed the critical divergence behavior of entropy wave attenuation in the Fermi superfluid under the strong interaction limit for the first time, revealing that there is a considerable critical region of phase transition in the system, and important transport coefficients such as thermal conductivity and viscosity coefficient are obtained. This work provides important experimental information for understanding the quantum transport phenomena of strongly interacting Fermi systems, and is an example of using quantum simulation to solve important physical problems. This result was published in the international academic journal Science a few days ago, which lays a foundation for further quantum simulation research using this system, so as to understand the abnormal transport phenomena in the strongly correlated Fermi system. (CCTV News)