Entropy

Energy is a central issue for the future, and we need a positive focus on where we can go. Accordingly, let us consider the Chinese pebble bed initiative: As a backgrounder, Wiki: The pebble-bed reactor (PBR) is a design for a graphite-moderated, gas-cooled nuclear reactor. It is a type of very-high-temperature reactor (VHTR), one of the six classes of nuclear reactors in the Generation IV initiative. The basic design of pebble-bed reactors features spherical fuel elements called pebbles. These tennis ball-sized pebbles (approx. 6.7 cm or 2.6 in in diameter) are made of pyrolytic graphite (which acts as the moderator), and they contain thousands of micro-fuel particles called TRISO particles. These TRISO fuel particles consist of a fissile material (such as 235U) Read More ›

It seems helpful to illustrate cosmological scale apparent aging as stars depart main sequence: An idealised, Hertzsprung-Russell chart for Hydrogen-rich balls prone to become fusion furnaces is: Here is a comparative plot (for open clusters), constructing a “clock” by projected pattern as a cluster ages, in effect seeing what is left as a candle burns down: This can be taken as illustrative of how our cosmos shows entropy-associated aging on the grand scale. Further illustrative, here is a NASA-derived cosmological timeline model, integrated with fine tuning: Speaking of fine tuning, Barnes et al summarise: All of this ties to core thermodynamics: Food for thought. END

On August 7th, News started a discussion on time’s arrow (which ties to the second law of thermodynamics). I found an interesting comment by FF: FF, 4: >> It’s always frustrating to read articles on time’s arrow or time travel. In one camp, we have the Star Trek physics fanatics who believe in time travel in any direction. In the other camp, we have those who believe only in travel toward the future. But both camps are wrong. It is logically impossible for time to change at all, in any direction. We are always in the present, a continually changing present. This is easy to prove. Changing time is self-referential. Changing time (time travel) would require a velocity in time Read More ›

Our Physicist and Computer Scientist from Russia — and each element of that balance is very relevant — is back, with more.  MOAR, in fact. This time, he tackles the “terror-fitted depths” of thermodynamics and biosemiotics. (NB: Those needing a backgrounder may find an old UD post here and a more recent one here, helpful.) More rich food for thought for the science-hungry masses, red hot off the press: _________________ >>On the Second Law of Thermodynamics in the context of the origin of life Rudolf Clausius (1822-1888) This note was motivated by my discussions with Russian interlocutors. One of UD readers here has asked me to produce a summary of those discussions, which I am happy to do now. I Read More ›

Mutations are used to explain evolution but also cause cancer. Biologists have discovered conditions for multiple mutations. Can we therefore infer that evolution via mutations is more likely? or that enhanced mutations will cause faster species degradation and extinction?

Biologists describe mechanism promoting multiple DNA mutations

DNA mutations—long known to fuel cancer as well as evolutionary changes in a living organism—had been thought to be rare events that occur randomly throughout the genome.

However, recent studies have shown that cancer development frequently involves the formation of multiple mutations that arise simultaneously and in close proximity to each other. . . .Anna Malkova, associate professor of biology in the UI College of Liberal Arts and Sciences, notes that the DNA repair pathway, known as break-induced replication (BIR), can promote clusters of DNA mutations.

“Previously, we have shown that double-strand DNA breaks, which can result from oxidation, ionizing radiation and replication errors, can be repaired by BIR,” says Malkova.

“During BIR, one broken DNA end is paired with an identical DNA sequence on another chromosome and initiates an unusual type of replication, which proceeds as a migrating bubble and is associated with the accumulation of large amounts of single-strand DNA,” she says.

In the Cell Reports study, researchers subjected yeast cells undergoing BIR to alkylating (cancer cell-killing agents) damage. “We found that the single-stranded DNA regions that accumulate during BIR are susceptible to damage that leads to the formation of mutation clusters,” explains Cynthia Sakofsky, postdoctoral fellow at the UI and one of two co-first authors on the paper. “These clusters are similar to those found in human cancer,” she says.

Importantly, say the researchers, the paper provides a mechanism to potentially explain how genetic changes form in human cancers. Thus, it will be critical for future research to determine whether BIR can form clustered mutations that lead to cancer in humans.

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