Dolphin: It's my friend's urine! Let me taste it carefully丨Tech Weekly

Welcome to watch the science of the week. This week you will see: ① Know your friends by tasting urine; ② The last selfie of Insight; ③ Salamander skydiving; ④ Molecular Möbius strip; ⑤ Global warming steals your sleep.

Know your friends by tasting their urine

A study published in Science Advances showed that bottlenose dolphins (Tursiops truncatus) can identify each other by tasting their urine, the first evidence found that animals can identify each other through taste alone[1].

In addition to sound, bottlenose dolphins Tursiops truncatus also recognize each other through taste cues | pixabay

The researchers collected urine from different dolphins, added the urine samples to the water in front of the dolphins, and observed their reactions. The results showed that the dolphins seemed to be particularly interested in the urine from familiar companions: they opened their mouths and carefully identified the seawater mixed with familiar urine, spending much more time than the control of unfamiliar urine or clean water. If the iconic sound from the same familiar individual was played while adding urine, it would attract the attention of the dolphins.

Dolphins lack a complete olfactory system, and their nasal cavity is separated from their oropharynx, so the researchers believe that they distinguish the taste of urine rather than the smell. The researchers speculate that the dolphins may recognize the protein or lipid components in the urine.

The last selfie

As its battery power ran low, the InSight Mars rover began to count down its life. The following picture became its last selfie[2].

The final selfie of the InSight Mars rover | NASA

This photo was taken on April 24, the 1,211th Martian day of InSight's mission. On May 22, the team retracted the robotic arm used to take the selfie and will no longer deploy it. As the solar panels accumulate dust, InSight is getting less and less power, now only one-tenth of what it was at the beginning of the mission. To save energy, it will now focus only on its core mission of detecting Martian seismic waves to extend data collection time as much as possible. If the situation does not improve, InSight is expected to terminate its Mars exploration in late summer and completely lose contact with people on Earth by the end of this year[3].

Salamander skydiving

In the canopy of a 60-meter-high redwood tree, there lives a type of salamander that is only about 10 centimeters long. They are called "vagrant salamanders" (Aneides vagrans), and they can live in a tree for their entire lives and rarely appear on the ground. But if there is any movement, they will jump from the canopy and glide into the thin air - but aren't they afraid of falling to death?

Wandering salamanders move in the mid-air canopy | Christian Brown

The researchers found that when salamanders jump, they spread their limbs and make the same movements as human skydivers. Using a vertical wind tunnel, the researchers further observed that this salamander can reduce its descent speed in the air by 10% and even float in the air for up to 10 seconds. They can also use their flexible tails to control the angle and move horizontally. Even if they are upside down, they can turn over in the air. For comparison, the researchers tested three other salamanders: non-arboreal salamanders seemed to have no way to land vertically; and the other two arboreal salamanders did not make skydiving movements as frequently as the wandering salamanders.

Molecular Möbius strip

Chemists have created the world's smallest Möbius strip: a twisted ring-shaped molecule with a skeleton made of carbon atoms.

The new molecule is called a "Möbius carbon nanoribbon" | Issey Takahashi

Using precursor molecules with an odd number of repeating units, Nagoya University researchers completed this challenging synthesis through a total of 14 chemical reactions, and confirmed the structural characteristics of the product through analytical methods such as nuclear magnetic resonance and circular dichroism spectroscopy.

Illustration of a "molecular Möbius strip" structure, with carbon atoms shown in red or blue and hydrogen atoms shown in white | Yasutomo Segawa et al.

At present, the molecular Möbius strip has no practical application value, but researchers believe that the new nanocarbon structure and the synthesis technology behind it can bring many new possibilities. "The ultimate goal of organic chemistry is to create all possible molecular structures, and our results are a big step towards this goal," said the paper's author, Yasutomo Sekawa.[5]

Sleepless

A warming climate is stealing our sleep: 44 hours of sleep loss per person per year, a new study shows.

Increasingly hot weather affects people's sleep | pixabay

The researchers collected daily sleep data from 47,628 adults using monitoring bracelets and combined the data with local weather records for analysis. The data was collected from 2015 to 2017 and covered 68 different countries.

Studies have shown that hot nights can cause people to go to bed later and wake up earlier. On nights above 30°C, people’s sleep duration is reduced by an average of 14 minutes. The sleep of the elderly and residents of low-income countries is more affected, and women are more affected than men. According to researchers’ estimates, by the end of this century, sleep loss caused by hot climates may increase to 50-58 hours per person per year[6].

References

[1] https://www.science.org/doi/10.1126/sciadv.abm7684

[2] https://www.nasa.gov/image-feature/insights-final-selfie

[3] https://mars.nasa.gov/news/9191/nasas-insight-still-hunting-marsquakes-as-power-levels-diminish/

[4] https://www.cell.com/current-biology/fulltext/S0960-9822(22)00602-9

[5] https://www.newscientist.com/article/2321185-tiny-mobius-strip-fashioned-from-carbon-nanotube-building-blocks/

[6] https://www.cell.com/one-earth/fulltext/S2590-3322(22)00209-3

Author: Mai Mai, Rain Knocking on the Window

Edit: Window knocking rain

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