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Interstellar dust captures a significant fraction of elements heavier than helium in the solid state and is an indispensable component both in theory and observations of galaxy evolution.

Dust emission is generally the primary coolant of the interstellar medium (ISM) and facilitates the gravitational collapse and fragmentation of gas clouds from which stars form, while altering the emission spectrum of galaxies from ultraviolet (UV) to far-infrared wavelengths through the reprocessing of starlight. However, the astrophysical origin of various types of dust grains remains an open question, especially in the early Universe.

Here we report direct evidence for the presence of carbonaceous grains from the detection of the broad UV absorption feature around 2175A˚ in deep near-infrared spectra of galaxies up to the first billion years of cosmic time, at a redshift (z) of ∼7. This dust attenuation feature has previously only been observed spectroscopically in older, more evolved galaxies at redshifts of z3. The carbonaceous grains giving rise to this feature are often thought to be produced on timescales of hundreds of millions of years by asymptotic giant branch (AGB) stars. Our results suggest a more rapid production scenario, likely in supernova (SN) ejecta.

University of Chicago scientists have discovered a new wrinkle in our understanding of how our genes work. The team, led by Chuan He, the UChicago John T. Wilson Distinguished Service Professor of Chemistry, Biochemistry and Molecular Biology, shed light on a longstanding puzzle involved in a common way our genes are modified that is known as RNA methylation.

Published Jan. 27 in Science, the finding could have implications for gene therapies for disease, as well as our picture of gene expression, development, and evolution.

For more than a decade, Chuan He’s laboratory has been focused on trying to unravel the puzzle of a phenomenon called RNA methylation, which we are increasingly understanding plays a key role in our bodies and lives—everything from cancer to PTSD to aging.

In quantum mechanics, the unitary nature of time evolution makes it intrinsically reversible, given control over the system in question. Remarkably, there have been several recent demonstrations of protocols for reverting unknown unitaries in scenarios where even the interactions with the target system are unknown. These protocols are limited by their probabilistic nature, raising the fundamental question of whether time-reversal could be performed deterministically. Here we show that quantum physics indeed allows for this by exploiting the non-commuting nature of quantum operators, and demonstrate a recursive protocol for two-level quantum systems with an arbitrarily high probability of success. Using a photonic platform, we achieve an average rewinding fidelity of over 95%. Our protocol, requiring no knowledge of the quantum process to be rewound, is optimal in its running time, and brings quantum rewinding into a regime of practical relevance.

Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

𝐓𝐡𝐞 𝐧𝐞𝐨𝐜𝐨𝐫𝐭𝐞𝐱 𝐬𝐭𝐚𝐧𝐝𝐬 𝐨𝐮𝐭 𝐚𝐬 𝐚 𝐬𝐭𝐮𝐧𝐧𝐢𝐧𝐠 𝐚𝐜𝐡𝐢𝐞𝐯𝐞𝐦𝐞𝐧𝐭 𝐨𝐟 𝐛𝐢𝐨𝐥𝐨𝐠𝐢𝐜𝐚𝐥 𝐞𝐯𝐨𝐥𝐮𝐭𝐢𝐨𝐧. 𝐀𝐥𝐥 𝐦𝐚𝐦𝐦𝐚𝐥𝐬 𝐡𝐚𝐯𝐞 𝐭𝐡𝐢𝐬 𝐬𝐰𝐚𝐭𝐡 𝐨𝐟 𝐭𝐢𝐬𝐬𝐮𝐞 𝐜𝐨𝐯𝐞𝐫𝐢𝐧𝐠 𝐭𝐡𝐞𝐢𝐫 𝐛𝐫𝐚𝐢𝐧, 𝐚𝐧𝐝 𝐭𝐡𝐞 𝐬𝐢𝐱 𝐥𝐚𝐲𝐞𝐫𝐬 𝐨𝐟 𝐝𝐞𝐧𝐬𝐞𝐥𝐲 𝐩𝐚𝐜𝐤𝐞𝐝 𝐧𝐞𝐮𝐫𝐨𝐧𝐬 𝐰𝐢𝐭𝐡𝐢𝐧 𝐢𝐭 𝐡𝐚𝐧𝐝𝐥𝐞 𝐭𝐡𝐞 𝐬𝐨𝐩𝐡𝐢𝐬𝐭𝐢𝐜𝐚𝐭𝐞𝐝 𝐜𝐨𝐦𝐩𝐮𝐭𝐚𝐭𝐢𝐨𝐧𝐬 𝐚𝐧𝐝 𝐚𝐬𝐬𝐨𝐜𝐢𝐚𝐭𝐢𝐨𝐧𝐬 𝐭𝐡𝐚𝐭 𝐩𝐫𝐨𝐝𝐮𝐜𝐞 𝐜𝐨𝐠𝐧𝐢𝐭𝐢𝐯𝐞 𝐩𝐫𝐨𝐰𝐞𝐬𝐬. 𝐒𝐢𝐧𝐜𝐞 𝐧𝐨 𝐚𝐧𝐢𝐦𝐚𝐥𝐬 𝐨𝐭𝐡𝐞𝐫 𝐭𝐡𝐚𝐧 𝐦𝐚𝐦𝐦𝐚𝐥𝐬 𝐡𝐚𝐯𝐞 𝐚 𝐧𝐞𝐨𝐜𝐨𝐫𝐭𝐞𝐱, 𝐬𝐜𝐢𝐞𝐧𝐭𝐢𝐬𝐭𝐬 𝐡𝐚𝐯𝐞 𝐰𝐨𝐧𝐝𝐞𝐫𝐞𝐝 𝐡𝐨𝐰 𝐬𝐮𝐜𝐡 𝐚 𝐜𝐨𝐦𝐩𝐥𝐞𝐱 𝐛𝐫𝐚𝐢𝐧 𝐫𝐞𝐠𝐢𝐨𝐧 𝐞𝐯𝐨𝐥𝐯𝐞𝐝.

The brains of reptiles seemed to offer a clue. Not only are reptiles the closest living relatives of mammals, but their brains have a three-layered structure called a dorsal ventricular ridge, or DVR, with functional similarities to the neocortex.

The neocortex stands out as a stunning achievement of biological evolution. All mammals have this swath of tissue covering their brain, and the six layers of densely packed neurons within it handle the sophisticated computations and associations that produce cognitive prowess. Since no animals other than mammals have a neocortex, scientists have wondered how such a complex brain region evolved.

Continue reading “Gene Expression in Neurons Solves a Brain Evolution Puzzle” »

An anthropologist imagines a world in which Neanderthals—and their relationships with the environment and one another—survived evolution.

The number of active fires recorded in the Brazilian Amazon in August-September 2022 was the highest since 2010, according to an article published in the journal Nature Ecology & Evolution. Besides the record number of fires (74,398), the researchers found they were due not to extreme drought, as in 2010, but to recent deforestation by humans.

“The idea of publishing our findings came up when we analyzed data provided free of charge by the Queimadas program,” said Guilherme Mataveli, first author of the article. ‘Queimadas’ in Portuguese means burnings, and he was referring to the forest fire monitoring service run by the National Space Research Institute (INPE). Mataveli is currently a postdoctoral researcher in INPE’s Earth Observation and Geoinformatics Division.

The number of fires typically rises every year in August and September, when the weather favors fire in about half of the Amazon. “But the surge in the number of fires in 2010 was due to an extreme drought event that occurred in a large part of the region, whereas nothing similar occurred in 2022, so other factors must have been to blame,” Mataveli said.

Science Daily reports that the astronomers found out that the mass of this lone white dwarf is equivalent to 56% of the sun’s weight. It aligns with previous theoretical predictions regarding the white dwarf’s mass, and it also sheds light on persisting theories regarding the evolution of these white dwarfs as a result of usual star evolution. The interesting observation grants further understanding of theories regarding white dwarf composition and structure.

According to the Space Academy, the astronomers made use of the renowned Hubble Space Telescope to gauge this lone white dwarf’s mass. The dwarf is known as LAWD 37.

Yes, the world has some serious problems, but if we did not have problems, we would never be forced to find new solutions. Problems push progress forward. Let’s embrace our ultimate existential challenges and come together to solve them. It is time to forget our differences and think of ourselves only as humans, engaged in a common biological and moral struggle. If the cosmic perspective, and the philosophy of poetic meta-naturalism, or some similar world-view of evolution and emergence, can build a bridge between the reductionist worldview and the religions of the world, then we can be optimistic that a new level of order and functionality will emerge from the current sea of chaos.

Knowledge is enlightenment, knowledge is transcendence, and knowledge is power. The tendency toward disorder described by the second law requires that life acquire knowledge forever, giving us all an individual and collective purpose by creating the constraint that forces us to create. By becoming aware of our emergent purpose, we can live more meaningful lives, in harmony with one another and with the aspirations of nature. You are not a cosmic accident. You are a cosmic imperative.

Monkeyflowers glow in a rich assortment of colors, from yellow to pink to deep red-orange. But about 5 million years ago, some of them lost their yellow. In the Feb. 10 issue of Science, UConn botanists explain what happened genetically to jettison the yellow pigment, and the implications for the evolution of species.

Monkeyflowers are famous for growing in harsh, mineral-rich soils where other plants can’t. They are also famously diverse in shape and color. Monkeyflowers also provide a textbook example of how a single-gene change can make a new species. In this case, a monkeyflower species lost the yellow pigments in the petals but gained pink about 5 million years ago, attracting bees for pollination. Later, a descendent species accumulated mutations in a gene called YUP that recovered the yellow pigments and led to production of red flowers. The species stopped attracting bees. Instead, hummingbirds pollinated it, isolating the red flowers genetically and creating a new species.

UConn botanist Yaowu Yuan and postdoctoral researcher Mei Liang (currently a professor at South China Agricultural University), with collaborators from four other institutes, have now shown exactly which gene changed to prevent monkeyflowers from making yellow. Their research, published this week in Science, adds weight to a theory that new genes create phenotypic diversity and even new species.