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Category: evolution – Page 28

“This study has changed the picture of the environments around stars less massive than our Sun, which emit very little UV light outside of flares,” said Jason Hinkle.

How can red dwarf stars, which are both smaller and cooler than our Sun, influence the habitability potential for exoplanets orbiting them? This is what a recent study published in the Monthly Notices of the Royal Astronomical Society hopes to address as a team of international researchers led by the University of Hawai’i investigated how stellar flares emanating from red dwarf stars could help ascertain the habitability potential for exoplanetary systems. This study holds the potential to help astronomers better understand the formation and evolution of exoplanetary systems throughout the cosmos and the conditions necessary for life to exist on these worlds.

For the study, the researchers analyzed near-ultraviolet (near-UV) and far-ultraviolet (far-UV) data obtained from the now-retired NASA GALEX space telescope of 182 stellar flares emitting from 158 stars within 100 parsecs (326 light-years) from Earth. The goal of the study was to ascertain how UV emissions influence whether a planet can host life.

In the end, the researchers found that UV radiation can either contribute to or dampen the possibility of life forming on such worlds, and specifically challenges previous hypotheses pertaining to far-UV radiation, which the researchers estimate can range between 3–12 times the energy levels compared to previously assertions. However, the team notes the processes responsible for the stronger far-UV radiation remains a mystery.

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A new study finds clues lurking in the Red Planet’s soil. The question of whether Mars ever supported life has captivated the imagination of scientists and the public for decades. Central to the discovery is gaining insight into the past climate of Earth’s neighbor: was the planet warm and wet, with seas and rivers much like those found on our own planet? Or was it frigid and icy, and therefore potentially less prone to supporting life as we know it? A new study finds evidence to support the latter by identifying similarities between soils found on Mars and those of Canada’s Newfoundland, a cold subarctic climate.

The study, published July 7th in Communications Earth and Environment, looked for soils on Earth with comparable materials to Mars’ Gale Crater. Scientists often use soil to depict environmental history, as the minerals present can tell the story of landscape evolution through time. Understanding more about how these materials formed could help answer long-standing questions about historical conditions on the red planet. The soils and rocks of Gale Crater provide a record of Mars’ climate between 3 and 4 billion years ago, during a time of relatively abundant water on the planet — and the same time period that saw life first appear on Earth.

“Gale Crater is a paleo lakebed — there was obviously water present. But what were the environmental conditions when the water was there?” says Anthony Feldman, a soil scientist and geomorphologist now at DRI. “We’re never going to find a direct analog to the Martian surface, because conditions are so different between Mars and Earth. But we can look at trends under terrestrial conditions and use those to try to extrapolate to Martian questions.”

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Chromosomes are threadlike structures composed entirely of DNA that reside in the cells of all living things. Each one of these biological databanks contains a wealth of genetic information that scientists can use to glean insights into the history and evolution of life on Earth. Normally, the remains of dead creatures degrade over time, causing DNA to fragment. Most ancient animal DNA discovered to date has been incomplete, often comprised of fewer than 100 base pairs out of the billions that once made up the full sequence of the organism.

However, the 52,000-year-old skin sample at the heart of this research was taken from behind the ear of a mammoth discovered in Northern Siberia in 2018. An intensive analysis of the sample revealed the presence of complete fossil chromosomes. These chromosomes, each measuring billionths of a meter in length, had seemingly been frozen in a glass-like state for tens of thousands of years. Knowing the shape of an organism’s chromosomes can help researchers to assemble entire DNA sequences of extinct creatures, a task previously deemed nearly impossible due to DNA degradation over time.

“This is a new type of fossil, and its scale dwarfs that of individual ancient DNA fragments — a million times more sequence,” explained Erez Lieberman Aiden, a corresponding author on the study and director of the Center for Genome Architecture at the Baylor College of Medicine.

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Contrary to widespread belief, our Moon does have an atmosphere, albeit extremely thin and officially known as an “exosphere”. But what are the processes responsible for forming and maintaining this exosphere, which have eluded scientists for some time? This is what a recent study published in Science Advances hopes to address as a team of researchers investigated how a phenomenon known as “impact vaporization” from the surface being hit my objects ranging from micrometeoroids to massive meteorites during its recent and ancient history, respectively. This study holds the potential to help scientists better understand the formation and evolution of planetary bodies throughout the solar system and the processes that maintain them today.

For the study, the team analyzed 10 Apollo lunar samples (one volcanic and nine lunar regolith aka “lunar soil”) collected by astronauts over five landing sites with the goal of ascertaining how much space weathering they’ve endured over the Moon’s long history. This is because when an impact occurs, this causes the specific atoms to vaporize and kick up portions of this material into space while other portions remain trapped by lunar gravity, although now orbiting the Moon. In the end, the researchers discovered that impact vaporization is the main process responsible for the lunar exosphere over the several billion-year history of the Moon.

“We give a definitive answer that meteorite impact vaporization is the dominant process that creates the lunar atmosphere,” said Dr. Nicole Nie, who is an assistant professor in MIT’s Department of Earth, Atmospheric, and Planetary Sciences and lead author of the study. “The moon is close to 4.5 billion years old, and through that time the surface has been continuously bombarded by meteorites. We show that eventually, a thin atmosphere reaches a steady state because it’s being continuously replenished by small impacts all over the moon.”

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The new groundbreaking Language Velocity Field (LVF) method is helping researchers trace dispersion patterns of languages, including Greek, across the world.

The spatial evolution of languages can help deepen our understanding of people diffusion and cultural spread. The language velocity field estimation is different from the frequently used phylogeographic approach which cannot fully explain the language evolution induced by the horizontal contact among languages, such as borrowing and areal diffusion.

The study of language evolution, particularly its spatial dispersion, offers valuable insights into our collective past. Traditional approaches, such as the phylogeographic approach, often miss the complexity of language evolution.

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How do giant planets form and is this process slow or fast based on the amount of available dust used to build those planets? This is what a recent study published in Astronomy & Astrophysics hopes to address as a team of researchers from Germany investigated how sub-micron-sized dust kicks off the planetary formation process within a protoplanetary disc. This study holds the potential to help scientists better understand the formation and evolution of planets throughout our solar system and exoplanetary systems, as well.

For the study, the researchers developed first-of-its-kind model to involve all constituents responsible for the physical processes that from planets. Focusing on sub-micron-sized dust, they included factors such as pebble accumulation, planetary gas buildup, planetary migration, and dust buildup, among others. In the end, they found that ring-shaped disturbances in the protoplanetary disk, which they refer to as substructures, can result in multiple gas giants’ formation in rapid sequence.

Dr. Til Birnstiel, who is a professor of theoretical astrophysics at Ludwig-Maximilians-Universität München and a co-author on the study, said: “When a planet gets large enough to influence the gas disk, this leads to renewed dust enrichment farther out in the disk. In the process, the planet drives the dust – like a sheepdog chasing its herd – into the area outside its own orbit.”

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Analyzed the global trends in this area of neuroscience. To identify and further facilitate the development of cerebral organoids, we utilized bibliometrics and visualization methods to analyze the global trends and evolution of brain organoids in the last 10 years. First, annual publications, countries/regions, organizations, journals, authors, co-citations, and keywords relating to brain organoids were identified. The hotspots in this field were also systematically identified. Subsequently, current applications for brain organoids in neuroscience, including human neural development, neural disorders, infectious diseases, regenerative medicine, drug discovery, and toxicity assessment studies, are comprehensively discussed.

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The Cartesian model of mind-body dualism concurs with religious traditions. However, science has supplanted this idea with an energy-matter theory of consciousness, where matter is equivalent to the body and energy replaces the mind or soul. This equivalency is analogous to the concept of the interchange of mass and energy as expressed by Einstein’s famous equation [Formula: see text]. Immanuel Kant, in his Critique of Pure Reason, provided the intellectual and theoretical framework for a theory of mind or consciousness. Any theory of consciousness must include the fact that a conscious entity, as far as is known, is a wet biological medium (the brain), of stupendously high entropy. This organ or entity generates a field that must account for the “binding problem”, which we will define. This proposed field, the conscious electro-magnetic information (CEMI) field, also has physical properties, which we will outline. We will also demonstrate the seamless transition of the Kantian philosophy of the a priori conception of space and time, the organs of perception and conception, into the CEMI field of consciousness. We will explore the concept of the CEMI field and its neurophysiological correlates, and in particular, synchronous and coherent gamma oscillations of various neuronal ensembles, as in William J Freeman’s experiments in the early 1970s with olfactory perception in rabbits. The expansion of the temporo-parietal-occipital (TPO) cortex in hominid evolution epitomizes metaphorical and abstract thinking. This area of the cortex, with synchronous thalamo-cortical oscillations has the best fit for a minimal neural correlate of consciousness. Our field theory shifts consciousness from an abstract idea to a tangible energy with defined properties and a mathematical framework. Even further, it is not a coincidence that the cerebral cortex is very thin with respect to the diameter of the brain. This is in keeping with its fantastically high entropy, as we see in the event horizon of a black hole and the conformal field theory/anti-de Sitter (CFT/ADS) holographic model of the universe. We adumbrate the uniqueness of consciousness of an advanced biological system such as the human brain and draw insight from Avicenna’s gendanken, floating man thought experiment. The multi-system high volume afferentation of a biological wet system honed after millions of years of evolution, its high entropy, and the CEMI field variation inducing currents in motor output pathways are proposed to spark the seeds of consciousness. We will also review Karl Friston’s free energy principle, the concept of belief-update in a Bayesian inference framework, the minimization of the divergence of prior and posterior probability distributions, and the entropy of the brain. We will streamline these highly technical papers, which view consciousness as a minimization principle akin to Hilbert’s action in deriving Einstein’s field equation or Feynman’s sum of histories in quantum mechanics. Consciousness here is interpreted as flow of probability densities on a Riemmanian manifold, where the gradient of ascent on this manifold across contour lines determines the magnitude of perception or the degree of update of the belief-system in a Bayesian inference model. Finally, the science of consciousness has transcended metaphysics and its study is now rooted in the latest advances of neurophysiology, neuro-radiology under the aegis of mathematics.

Keywords: anatomy & physiology; brain anatomy; disorders of consciousness; philosophy.

Copyright © 2020, Kesserwani et al.

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