‘Could the theory be wrong? Possibly. That is the point and the case for all theories,’ says Cronin. ‘But perhaps it is less wrong than our current understanding and it will help us understand the link between physics and biology through chemistry. We have to try and we think we are onto something.’
A Sharma et al, Nature., 2023, DOI: 10.1038/s41586-023–06600-9.
Life on Earth began from a single-celled microbe, while the rise to the multicellular world in which we live arose due a vital chemical process known as biomineralization, during which living organisms produce hardened mineralized tissue, such as skeletons. Not only did this phenomenon give rise to the plethora of body plans we see today, but it also had a major impact on the planet’s carbon cycle.
Fossil skeletons of cloudinids (Cloudina), tubular structures comprised of carbonate cones up to ~1.5cm in length, have been found in Tsau Khaeb National Park, Namibia, dating back to 551–550 million years ago in the Ediacaran (~635–538 million years ago). Dr. Fred Bowyer, from the University of Edinburgh, and colleagues aimed to use these fossils to define the location, timing and reason for why biomineralization initiated on Earth and the magnitude of its impact.
New research published in Earth and Planetary Science Letters combines sediment analysis with geochemical data in the form of carbon and oxygen isotopes (the same element with different atomic masses) from limestones in the Kliphoek Member, Nama Group. The research team suggest this rock was once deposited in a shallow sea during a lowstand before a period of transition to open marine conditions.
The anterior cingulate cortex (ACC) is believed to be involved in many cognitive processes, including linking goals to actions and tracking decision-relevant contextual information. ACC neurons robustly encode expected outcomes, but how this relates to putative functions of ACC remains unknown. Here, we approach this question from the perspective of population codes by analyzing neural spiking data in the ventral and dorsal banks of the ACC in two male monkeys trained to perform a stimulus-motor mapping task to earn rewards or avoid losses. We found that neural populations favor a low dimensional representational geometry that emphasizes the valence of potential outcomes while also facilitating the independent, abstract representation of multiple task-relevant variables. Valence encoding persisted throughout the trial, and realized outcomes were primarily encoded in a relative sense, such that cue valence acted as a context for outcome encoding. This suggests that the population coding we observe could be a mechanism that allows feedback to be interpreted in a context-dependent manner. Together, our results point to a prominent role for ACC in context setting and relative interpretation of outcomes, facilitated by abstract, or untangled, representations of task variables.
SIGNIFICANCE STATEMENT The ability to interpret events in light of the current context is a critical facet of higher-order cognition. The ACC is suggested to be important for tracking contextual information, whereas alternate views hold that its function is more related to the motor system and linking goals to appropriate actions. We evaluated these possibilities by analyzing geometric properties of neural population activity in monkey ACC when contexts were determined by the valence of potential outcomes and found that this information was represented as a dominant, abstract concept. Ensuing outcomes were then coded relative to these contexts, suggesting an important role for these representations in context-dependent evaluation. Such mechanisms may be critical for the abstract reasoning and generalization characteristic of biological intelligence.
“The surprising thing we found is that in a particular kind of crystal lattice, where electrons become stuck, the strongly coupled behavior of electrons in d atomic orbitals actually act like the f orbital systems of some heavy fermions,” said Qimiao Si, co-author of a study about the research in Science Advances
<em> Science Advances </em> is a peer-reviewed, open-access scientific journal that is published by the American Association for the Advancement of Science (AAAS). It was launched in 2015 and covers a wide range of topics in the natural sciences, including biology, chemistry, earth and environmental sciences, materials science, and physics.
Your phone may have more than 15 billion tiny transistors packed into its microprocessor chips. The transistors are made of silicon, metals like gold and copper, and insulators that together take an electric current and convert it to 1s and 0s to communicate information and store it. The transistor materials are inorganic, basically derived from rock and metal.
But what if you could make these fundamental electronic components part biological, able to respond directly to the environment and change like living tissue?
This is what a team at Tufts University Silklab did when they created transistors replacing the insulating material with biological silk. They reported their findings in Advanced Materials.
How we grow old gracefully—and whether we can do anything to slow down the process—has long been a fascination of humanity. However, despite continued research the answer to how we can successfully combat aging still remains elusive.
Arithmetic, rooted in our biological perception, is a natural consequence of how we perceive and organize the world around us. This connection between perception and mathematical truths suggests that mathematics is both a uniquely human invention and a universal discovery, highlighting a profound unity between the mind and the physical universe…
Some of nature’s mysteries have kept scientists busy for decades—for example, the processes that drive evolution. The question of whether certain differences between and within species are caused by natural selection or by chance processes divides evolutionary biologists even today. Now, an international team of researchers has teased apart a scientific debate concerning the evolutionary theories of Darwin and the Japanese geneticist Kimura. Their conclusion: the debate is unnecessarily convoluted by the co-existence of different interpretations.
Due to his contributions to geological and biological sciences, British naturalist Charles Darwin (1809–1882) is considered one of the most important natural scientists. His influential work “On the Origin of Species” (1859), with its strictly scientific explanation of the diversity of life, forms the basis of modern evolutionary biology. Darwin concluded that species evolve through natural selection: well-adapted organisms survive, others don’t.
However, by the end of the 1960s, the Japanese geneticist Motoo Kimura (1924–1994) proposed that at the genetic level, most changes in the course of evolution do not offer direct advantages or disadvantages to the individual but are simply neutral. According to his “Neutral Theory of Molecular Evolution,” first published in 1968, most of the genetic variation within and between species arises from random fluctuations of neutral mutations.
Two astronauts will perform a spacewalk from the International Space Station, collecting samples from the station’s exterior to use in scientific research.
Scientists have caught fast-moving hydrogen atoms—the keys to countless biological and chemical reactions—in action.
A team led by researchers at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University used ultrafast electron diffraction (UED) to record the motion of hydrogen atoms within ammonia molecules. Others had theorized they could track hydrogen atoms with electron diffraction, but until now nobody had done the experiment successfully.
The results, published in Physical Review Letters, leverage the strengths of high-energy Megaelectronvolt (MeV) electrons for studying hydrogen atoms and proton transfers, in which the singular proton that makes up the nucleus of a hydrogen atom moves from one molecule to another.