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Using laser trapped atom lattices instead of solid metamaterials to achieve negative refraction!


A Beam of Light Undergoing Negative Refraction Within a Lattice of Laser-Trapped Atoms

A Beam of Light Undergoing Negative Refraction Within a Lattice of Laser-Trapped Atoms.

Highlights:

Researchers, led by the University of Melbourne’s Professor Laura Mackay, a Laboratory Head and Immunology Theme Leader at the Peter Doherty Institute of Infection and Immunity (Doherty Institute), in collaboration with Pfizer, have discovered new insights into possible future treatments for breast cancer.

A new dual-target drug that has been shown to supercharge cancer-fighting immune cells in mice may support a new treatment approach for patients, potentially paving the way for improved outcomes in breast cancer care.

Breast cancer is the fifth most common cause of cancer death in Australia, with more than 20,000 Australians diagnosed per year. Over 1,000 of those diagnosed are young Australian women under 40. There is an urgent need to discover more effective treatments for breast cancer.

Mice learn best when the opponent opposing forces of dopamine and serotonin work together, a new study shows, helping to resolve long-standing questions about the neuromodulators’ relationship.

In the intricate dance of learning and motivation, two key brain chemicals—dopamine (DA) and serotonin (5HT)—play opposing yet deeply interconnected roles. Scientists have long speculated how these neuromodulators work together to shape our ability to form new associations, but testing these theories directly has been a challenge.

Now, researchers have developed a new mouse model that allows them to simultaneously study both dopamine and serotonin neurons in the brain. Their experiments focused on the nucleus accumbens (NAc), a region known for processing rewards. By monitoring neural activity, they found that receiving a reward boosts dopamine signals while simultaneously suppressing serotonin signals.

To understand how this dynamic affects learning, the team used optogenetics—a technique that uses light to control brain activity. They found that disrupting dopamine or serotonin alone caused only mild learning impairments. However, when both signals were suppressed together, the mice struggled significantly to learn from rewards. On the flip side, artificially recreating both dopamine and serotonin responses helped the mice learn more effectively than manipulating either signal alone.

These findings reveal that dopamine and serotonin work in opposition to control reinforcement and learning. Instead of acting in isolation, they create a delicate balance that shapes how we associate actions with rewards—providing new insights into how the brain learns and adapts.

While most animals reproduce sexually, some species rely solely on females for parthenogenetic reproduction. Even in these species, rare males occasionally appear. Whether these males retain reproductive functions is a key question in understanding the evolution of reproductive strategies.

A new study published in Ecology by a research team led by Assistant Professor Tomonari Nozaki from the National Institute for Basic Biology, Professor Kenji Suetsugu from Kobe University, and Associate Professor Shingo Kaneko from Fukushima University provides insight into this question. The researchers focused on the rare males of Ramulus mikado, a stick insect species in Japan, where parthenogenesis is predominant. Their analysis of male reproductive behavior reveals new findings.

What if time is not as fixed as we thought? Imagine that instead of flowing in one direction—from past to future—time could flow forward or backwards due to processes taking place at the quantum level. This is the thought-provoking discovery made by researchers at the University of Surrey, as a new study reveals that opposing arrows of time can theoretically emerge from certain quantum systems.

For centuries, scientists have puzzled over the arrow of time—the idea that time flows irreversibly from past to future. While this seems obvious in our experienced reality, the underlying laws of physics do not inherently favor a single direction. Whether time moves forward or backwards, the equations remain the same.

Dr. Andrea Rocco, Associate Professor in Physics and Mathematical Biology at the University of Surrey and lead author of the study, said, One way to explain this is when you look at a process like spilled milk spreading across a table, it’s clear that time is moving forward. But if you were to play that in reverse, like a movie, you’d immediately know something was wrong—it would be hard to believe milk could just gather back into a glass.

In the grand sweep of scientific history, revolutions in thought are often born from a simple yet unsettling realization: that the fundamental nature of reality is not what we once assumed it to be. In the 20th century, physics was shaken by the twin cataclysms of relativity and quantum mechanics, revealing that space and time themselves were malleable, that particles could exist in superpositions, and that observation played a fundamental role in shaping what we call reality.

Imagine a scale that ranks civilizations not by their borders or technology, but by the sheer energy they command— some spanning entire galaxies. Join us as we explore the Kardashev Scale, the ultimate measure of cosmic power.

Watch my exclusive video Big Alien Theory https://nebula.tv/videos/isaacarthur–… Nebula using my link for 40% off an annual subscription: https://go.nebula.tv/isaacarthur Get a Lifetime Membership to Nebula for only $300: https://go.nebula.tv/lifetime?ref=isa… Use the link gift.nebula.tv/isaacarthur to give a year of Nebula to a friend for just $30. Visit our Website: http://www.isaacarthur.net Join Nebula: https://go.nebula.tv/isaacarthur Support us on Patreon: / isaacarthur Support us on Subscribestar: https://www.subscribestar.com/isaac-a… Facebook Group: / 1,583,992,725,237,264 Reddit: / isaacarthur Twitter: / isaac_a_arthur on Twitter and RT our future content. SFIA Discord Server: / discord Credits: The Kardashev Scale & Population Episode 486; February 13, 2025 Written, Produced & Narrated by: Isaac Arthur Editors: Ludwig Luska Graphics: Fishy Tree, Jeremy Jozwik, Ken York YD Visual Select imagery/video supplied by Getty Images Music Courtesy of Epidemic Sound http://epidemicsound.com/creator Phase Shift, “Forest Night” Chris Zabriskie, “Unfoldment, Revealment”, “A New Day in a New Sector”, “Oxygen Garden” Stellardrone, “Red Giant”, “Billions and Billions“
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Credits:
The Kardashev Scale & Population.
Episode 486; February 13, 2025
Written, Produced & Narrated by: Isaac Arthur.
Editors: Ludwig Luska.
Graphics: Fishy Tree, Jeremy Jozwik, Ken York YD Visual.
Select imagery/video supplied by Getty Images.
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator.
Phase Shift, \