1,258 research outputs found
The "enemies within":regions of the genome that are inherently difficult to replicate
An unusual feature of many eukaryotic genomes is the presence of regions that appear intrinsically difficult to copy during the process of DNA replication. Curiously, the location of these difficult-to-replicate regions is often conserved between species, implying a valuable role in some aspect of genome organization or maintenance. The most prominent class of these regions in mammalian cells is defined as chromosome fragile sites, which acquired their name because of a propensity to form visible gaps/breaks on otherwise-condensed chromosomes in mitosis. This fragility is particularly apparent following perturbation of DNA replication—a phenomenon often referred to as “replication stress”. Here, we review recent data on the molecular basis for chromosome fragility and the role of fragile sites in the etiology of cancer. In particular, we highlight how studies on fragile sites have provided unexpected insights into how the DNA repair machinery assists in the completion of DNA replication
Quantum Isometries of the finite noncommutative geometry of the Standard Model
We compute the quantum isometry group of the finite noncommutative geometry F
describing the internal degrees of freedom in the Standard Model of particle
physics. We show that this provides genuine quantum symmetries of the spectral
triple corresponding to M x F where M is a compact spin manifold. We also prove
that the bosonic and fermionic part of the spectral action are preserved by
these symmetries.Comment: 29 pages, no figures v3: minor change
Antibaryon yields in ultrahigh-energy collisions and the astroparticle implications
Some of the most recent results on antibaryon production in some ultrahigh-energy nuclear collisions are being analysed on the basis of a particle production model which has had some intrinsic features of non-standard nature. It is seen that the model could accommodate the data without any induction of the quark-gluon plasma (QGP) ideas which have, truly speaking, become a fad in the domain of the ultrahigh-energy nuclear collisions with some probable implications
for or impact upon astroparticle physics
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