Astronomers report the first direct evidence of an exoplanet being swallowed by an ancient Sun-like star, a fate that likely awaits the Earth in around five billion years.
Waste heat produced by solar cells undermines their performance, but the race is on to harness it for useful purposes. Researchers have found a way to tap into that heat to collect water out of the air, and have demonstrated the effectiveness of the idea by growing spinach in the Arabian desert, one of the driest places on Earth.
Stephen has a science degree with a major in physics, an arts degree with majors in English Literature and History and Philosophy of Science and a Graduate Diploma in Science Communication.
The eyeglasses, called EchoSpeech, use acoustic-sensing and artificial intelligence to continuously recognize up to 31 unvocalized commands, based on lip and mouth movements.
As sponges and ctenophores are such disparate animals13, the nature of the first diverging animal lineage has implications for the evolution of fundamental animal characteristics. Adult sponges are generally sessile filter-feeding organisms with body plans organized into reticulated water-filtration channels, structures built out of silica or calcium carbonate, and specialized cell types and tissues used for feeding, reproduction and self-defence, but they lack neuronal and muscle cells15. By contrast, ctenophores are gelatinous marine predators that move using eight longitudinal ‘comb rows’ of ciliary bundles16,17; they are superficially similar but unrelated to cnidarian medusae13,18 and possess multiple nerve nets19. Thus, whereas the sponge-sister scenario suggests a single origin of neurons on the ctenophore–parahoxozoan stem, the ctenophore-sister scenario implies either that either ancestral metazoan neurons were lost in the sponge lineage, or that there was convergent evolution of neurons in the ctenophore and parahoxozoan lineages3,6. Similar considerations apply to other metazoan cell types18, gene regulatory networks, animal development13,18 and other uniquely metazoan features.
Despite its importance for understanding animal evolution, the relative branching order of sponges, ctenophores and other animals has proven to be difficult to resolve2. The fossil record is largely silent on this issue as verified Precambrian sponge fossils are extremely rare20 and putative fossils of the soft-bodied ctenophores are difficult to interpret21. Morphological characters of living groups (for example, choanocytes of sponges) are not sufficient to resolve the question because true homology is difficult to assign, and such characters are easily lost or can arise convergently13,22. The ctenophore-sister hypothesis is supported by a pair of gene duplications shared by sponges, bilaterians, placozoans and cnidarians but not ctenophores23. Although sophisticated methods for sequence-based phylogenomics have been developed and applied to increasingly large molecular datasets, there is still considerable debate about the relative position of sponges and ctenophores as results are sensitive to how sequence evolution is modelled11, which taxa or sites are included24,25, and the effects of long-branch artifacts and nucleotide compositional variation26. New approaches are needed.
We reasoned that patterns of synteny, classically defined as chromosomal gene linkage without regard to gene order27, could provide a powerful tool for resolving the ctenophore-sister versus sponge-sister debate. Chromosomal patterns of gene linkage evolve slowly in many lineages12,28,29,30, probably because it is improbable for interchromosomal translocations to be fixed in populations with large effective population sizes28,31,32. Notably, some changes in synteny are effectively irreversible. For example, when two distinct ancestral synteny groups are combined onto a single chromosome by translocation, and subsequent intrachromosomal rearrangements mix these two groups of genes, it is very unlikely that the ancestral separated pattern will be restored by further rearrangement and fission, in the same sense that spontaneous reduction in entropy is improbable12. Such rare and irreversible changes are particularly useful for resolving challenging phylogenetic questions as they give rise to shared derived features that unambiguously unite all descendant lineages33,34,35. Deeply conserved syntenies observed between animals and their closest unicellular relatives12 suggest that outgroup comparisons could be used to infer ancestral metazoan states and polarize changes within animals to address the sponge-sister versus ctenophore-sister debate. Yet, chromosome-scale genome sequences of the unicellular or colonial eukaryotic outgroups closest to animals (choanoflagellates, filastereans and ichthyosporeans) have not been reported.
35-year-old Weibao Wang was charged with stealing Apple’s trade secrets for self-driving cars and fleeing to China. Officials say Wang is still at large and if convicted faces ten years in prison for each trade secret violation. NBC News’ Dana Griffin shares the latest.
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The threat that technology will replace workers is something more people are grappling with due to the introduction of new tools powered by generative artificial intelligence. Creative workers like artists, writers, and filmmakers are among those raising the loudest alarm. But is their concern warranted? And what impact could AI have on the future workforce?
Join us for the third episode of our series “Artificially Minded” with host Zoe Thomas.
A method for producing ultrashort, ultracold electron bunches could improve the resolution of electron-based imaging methods.
Quantum effects improve the performance of magnetic induction tomography—an imaging technique that has promising medical applications.
Micrometeoroids in Saturn’s rings reveal that these dusty bands are no more than 400 million years old, making them significantly younger than the 4.5-billion-year-old gas giant.
With its wide bands of encircling dust, Saturn’s rings are the biggest and brightest in our Solar System. They are also the most mysterious. Unanswered questions remain about why, how, and when the seven rings formed. Now Sascha Kempf of the University of Colorado Boulder and colleagues have addressed the latter problem, using dust contaminants within the rings to place an upper limit of 400 million years on the rings’ age [1]. Kempf says that for as long as he’s been in the field, astronomers have been discussing whether Saturn’s rings are as old as the planet or if they are younger. Now they know. “They are significantly younger,” he says.
Kempf and colleagues produced their age estimate by studying the contamination rate of the rings by small pieces of rock and debris, known as micrometeoroids. These contaminants are constantly zooming around our Solar System, colliding with objects in their paths. When one of these micrometeoroids hits one of Saturn’s rings it can get incorporated into the ice the rings contain. Kempf and colleagues realized they could use the rate at which this process happens as a clock to reveal the rings’ age.
