A canonical distribution on isoparametric submanifolds II

Polycomb silencing represses gene expression and provides a molecular memory of chromatin state that is essential for animal development. We show that Drosophila female germline stem cells (GSCs) provide a powerful system for studying Polycomb silencing. GSCs have a non-canonical distribution of PRC2 activity and lack silenced chromatin like embryonic progenitors. As GSC daughters differentiate into nurse cells and oocytes, nurse cells, like embryonic somatic cells, silence genes in traditional Polycomb domains and in generally inactive chromatin. Developmentally controlled expression of two Polycomb repressive complex 2 (PRC2)-interacting proteins, Pcl and Scm, initiate silencing during differentiation. In GSCs, abundant Pcl inhibits PRC2-dependent silencing globally, while in nurse cells Pcl declines and newly induced Scm concentrates PRC2 activity on traditional Polycomb domains. Our results suggest that PRC2-dependent silencing is developmentally regulated by accessory proteins that either increase the concentration of PRC2 at target sites or inhibit the rate that PRC2 samples chromatin.

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FLUCTUATIONS, CORRELATIONS AND FINITE VOLUME EFFECTS IN HEAVY ION COLLISION

International Journal of Modern Physics E ◽

10.1142/s0218301307007738 ◽

2007 ◽

Vol 16 (07n08) ◽

pp. 2229-2234

Author(s):

LUDWIK TURKO

Keyword(s):

Finite Volume ◽

Thermodynamic Limit ◽

Heavy Ion ◽

Higher Moments ◽

Heavy Ion Collision ◽

Canonical Distribution ◽

Statistical Ensembles ◽

Ion Collision ◽

Rigorous Procedure ◽

Grand Canonical

Finite volume corrections to higher moments are important observable quantities. They make possible to differentiate between different statistical ensembles even in the thermodynamic limit. It is shown that this property is a universal one. The classical grand canonical distribution is compared to the canonical distribution in the rigorous procedure of approaching the thermodynamic limit.

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Ensembles and the Canonical Distribution

Statistical and Thermal Physics ◽

10.1201/9781003028604-16 ◽

2021 ◽

pp. 149-167

Author(s):

Michael J.R. Hoch

Keyword(s):

Canonical Distribution

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On the Mathematical Definition of Entropy

Zeitschrift für Naturforschung A ◽

10.1515/zna-1974-0901 ◽

1974 ◽

Vol 29 (9) ◽

pp. 1239-1243

Author(s):

Bo-Sture Skagerstam

Keyword(s):

Weak Sense ◽

Canonical Distribution ◽

Mathematical Definition ◽

Definition Of

We discuss the Baron-Jauch definition of entropy and show that it is the unique answer to an entropy which has the properties of extensivity, positivity and continuity in a weak sense. As an application we also show how one easily can derive the canonical distribution from this definition of entropy using information theoretical arguments.

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