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Purple-crowned fairy-wrens get frisky outside breeding season

Researchers and ecologists in the central Kimberley have been left scratching their heads after an unexpected increase in the out-of-season breeding escapades of the purple-crowned fairy-wren.

They’ve been caught copulating throughout the dry season (May to November) for a second consecutive year, which is highly unusual as breeding usually takes place in the Wet (December to April).

In fact, most of the females caught during a survey in November 2021 had brood patches – bare patches on their belly which indicate that they were actively breeding.

“To be honest, it goes against what we thought we knew about the birds’ breeding behaviour, and we don’t quite understand the recent breeding activity by the wrens,” says Dr Niki Teunissen of Monash University. “It raises more exciting research questions for us to answer!”

The good news is that thanks to this extended period of knocking feathers they’ve seen a big boost in the numbers of these at-risk birds, with the population soaring to 204 individuals from 143 in November 2020.

New method for early prediction of pre-eclampsia risk

Risk of pre-eclampsia, a leading cause of maternal morbidity and mortality, can be accurately predicted using a single blood sample, a paper published in Nature has reported.

The method relies on the sequencing of cell-free RNA found in the mother’s blood to monitor the activation of maternal and foetal genes.

RNA is the messenger molecule in our cells that translates the genetic instructions in DNA into functional proteins. By looking at the RNA floating around in a pregnant woman’s body, the researchers were able to track which genes were expressed or ‘switched on’.

Screening the expression patterns of seven genes associated with pre-eclampsia allowed the researchers to predict this complication with a seven-fold improvement in accuracy over current methods.

Moreover, the test was able to correctly identify 73% of individuals who ended up experiencing pre-eclampsia – over three months before symptoms appeared. This early detection of risk could help clinicians and expectant parents better manage the risks of this severe complication.

“Looking at the progression of genes expressed in the mother and baby during pregnancy offers an entirely new way of characterising their health that hasn’t been available up until now,” says senior author Thomas McElrath.

Authors on the study were financially associated with Mirvie, a biotechnology company focusing on early detection of pregnancy complications.

Deep sea microbes can produce oxygen without light

Scientists have solved the puzzle of how a group of common, yet mysterious, marine microbes survive in the ocean depths.

The microbe family, known as ammonia-oxidising archaea, are extremely abundant in the ocean and play important roles in the planet’s nitrogen cycle.

“These microbes are so common that every fifth cell in a bucket of sea water is one of them,” says Don Canfield, co-author on the paper published in Science.

Like many other organisms, the ammonia-oxidising archaea rely on oxygen to carry out everyday chemical reactions in their cells – but scientists noticed that the archaea could, mysteriously, continue these reactions even in a low-oxygen environment.

So where were they getting that oxygen from? Turns out they were able to make it themselves using nitrogen in their environment – even in the dark. By contrast, most of Earth’s oxygen is produced by photosynthesis, which requires light energy.

“If this lifestyle is widespread in the oceans, it certainly forces us to rethink our current understanding of the marine nitrogen cycle,” says lead author Beate Kraft.

New technique successfully detects interstellar magnetic field

Picture of molecules and telescope superimposed on galaxy
The Taurus molecular cloud (grey scale), of which L1544 is a part, is superimposed onto the 2MASS sky image and the field orientation based on Planck data (thin white lines). The HINSA Zeeman spectrum (thick white line) is shown with the fitted Zeeman signature (blue). Credit: NAOC

A paper published in Nature has shifted scientists’ understanding of interstellar magnetic fields.

Such fields are key in star formation, which takes place in molecular clouds – but our ability to measure and study them has so far been limited. That’s because the Zeeman effect – the only direct way to measure interstellar magnetic field strength – is weak and difficult to detect.

However, scientists have now been able to harness the power of the Five-hundred-metre Aperture Spherical radio Telescope (FAST) to boost their Zeeman effect measurements at the interstellar scale.

Specifically, they did this by using the HI Narrow Self-Absorption (HINSA) technique, which involves looking at a signal created by hydrogen atoms cooled through collisions with hydrogen molecules within molecular clouds.

With this technique, the team accurately measured the strength of a magnetic field in the molecular cloud L1544, showing that this field’s strength is about six million times weaker than that of Earth’s.

Not only did the study demonstrate that the new technique was successful, it also furnished some surprising implications for our current understanding of magnetic fields and star formation. The magnetic field in L1544 had a coherent structure with similar orientation and magnitude across different components of the cloud.

To enable a molecular cloud to collapse under its own gravity and form a star, the magnetic field (which acts against gravity) must at some point dissipate. Prevailing theories have held that this occurs through ambipolar diffusion of particles in molecular cloud cores.

However, the data from L1544 suggested that the magnetic field actually dissipates during the formation of the molecular envelope around a nascent star, rather than in the core itself, casting doubt on the relevance of ambipolar diffusion.

Extremely cold sodium atoms form quantum tornadoes

Scientists from MIT have succeeded in pushing a cloud of sodium atoms into the quantum world.

The laws of physics differ depending on scale. From planets to humans to microorganisms, classical physics is king in most situations we can encounter or imagine. But at the scale of the very, very tiny, quantum rules can kick in and allow particles to behave in completely different ways.

The MIT team trapped a cloud of sodium atoms, cooled it to close to absolute zero, and used lasers and electromagnets to spin it around. As previously observed, the cloud first forms a kind of long fluid structure known as a Bose-Einstein condensate.

Pushed even further, the cloud enters the quantum world, which causes the atoms to form tiny tornado-like crystalline structures.

“The fluid, just from its quantum instabilities, fragments into this crystalline structure of smaller clouds and vortices,” says physicist Martin Zwierlein.

Under these conditions, the sodium atoms behave similarly to electrons in a magnetic field, meaning the phenomena observed in the study likely have applications for understanding quantum behaviour more broadly.

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