8,537 research outputs found
Wrapped brane gas as a candidate for Dark Matter
We consider brane gas models based on type II string theories and analyze the
mass, the Ramond-Ramond charge and the charge on moduli fluctuations of branes
wrapping over cycles of a compactified space in the four-dimensional Einstein
frame. A six-dimensional torus and Calabi-Yau threefolds are considered for the
Kaluza-Klein reduction. A large volume of the compactified space and a weak
string coupling gives rise to point particles of the wrapped branes which have
a light mass and a small charge of the Ramond-Ramond flux and of the moduli
fluctuations, while the particles become very heavy in the string frame. We
find that the masses and the charges satisfy the sea-saw like dual relations
which become time-independent in the four-dimensional Einstein frame.Comment: 17 pages, 2 figures, revtex4, v3: comments adde
The Steady State Distribution of the Master Equation
The steady states of the master equation are investigated. We give two
expressions for the steady state distribution of the master equation a la the
Zubarev-McLennan steady state distribution, i.e., the exact expression and an
expression near equilibrium. The latter expression obtained is consistent with
recent attempt of constructing steady state theormodynamics.Comment: 6 pages, No figures. A mistake was correcte
The focal developable and the binormal indicatrix of a nonlightlike curve in Minkowski 3-space
We define the binormal indicatrix and focal developable of a nonlightlike curve in Minkowski 3-space. We establish the relationships between singularities of these subjects and geometric invariants of curves under the action of Lorentzian group
Tre1 GPCR initiates germ cell transepithelial migration by regulating Drosophila melanogaster E-cadherin
Despite significant progress in identifying the guidance pathways that control cell migration, how a cell starts to move within an intact organism, acquires motility, and loses contact with its neighbors is poorly understood. We show that activation of the G protein–coupled receptor (GPCR) trapped in endoderm 1 (Tre1) directs the redistribution of the G protein Gβ as well as adherens junction proteins and Rho guanosine triphosphatase from the cell periphery to the lagging tail of germ cells at the onset of Drosophila melanogaster germ cell migration. Subsequently, Tre1 activity triggers germ cell dispersal and orients them toward the midgut for directed transepithelial migration. A transition toward invasive migration is also a prerequisite for metastasis formation, which often correlates with down-regulation of adhesion proteins. We show that uniform down-regulation of E-cadherin causes germ cell dispersal but is not sufficient for transepithelial migration in the absence of Tre1. Our findings therefore suggest a new mechanism for GPCR function that links cell polarity, modulation of cell adhesion, and invasion
Ferromagnetism and Superconductivity in the multi-orbital Hubbard Model: Hund's Rule Coupling versus Crystal-Field Splitting
The multi-orbital Hubbard model in one dimension is studied using the
numerical diagonalization method. Due to the effect of the crystal-field
splitting , the fully polarized ferromagnetism which is observed in the
strong coupling regime becomes unstable against the partially polarized
ferromagnetism when the Hund's rule coupling is smaller than a certain
critical value of order of . In the vicinity of the partially polarized
ferromagnetism, the orbital fluctuation develops due to the competition between
the Hund's rule coupling and the crystal-field splitting. The superconducting
phase with the Luttinger liquid parameter is observed for the
singlet ground state in this region.Comment: 4 pages,5 figures,submitted to J.Phys.Soc.Jp
cyTRON and cyTRON/JS: two Cytoscape-based applications for the inference of cancer evolution models
The increasing availability of sequencing data of cancer samples is fueling
the development of algorithmic strategies to investigate tumor heterogeneity
and infer reliable models of cancer evolution. We here build up on previous
works on cancer progression inference from genomic alteration data, to deliver
two distinct Cytoscape-based applications, which allow to produce, visualize
and manipulate cancer evolution models, also by interacting with public genomic
and proteomics databases. In particular, we here introduce cyTRON, a
stand-alone Cytoscape app, and cyTRON/JS, a web application which employs the
functionalities of Cytoscape/JS.
cyTRON was developed in Java; the code is available at
https://github.com/BIMIB-DISCo/cyTRON and on the Cytoscape App Store
http://apps.cytoscape.org/apps/cytron. cyTRON/JS was developed in JavaScript
and R; the source code of the tool is available at
https://github.com/BIMIB-DISCo/cyTRON-js and the tool is accessible from
https://bimib.disco.unimib.it/cytronjs/welcome
Superconductivity of the One-Dimensional d-p Model with p-p transfer
Using the numerical diagonalization method, we investigate the
one-dimensional - model, simulating a Cu-O linear chain with strong
Coulomb repulsions. Paying attention to the effect of the transfer energy
between the nearest neighbor oxygen-sites, we calculate the critical
exponent of correlation functions based on the Luttinger liquid
relations and the ground state energy as a function of an external
flux . We find that the transfer increases the charge
susceptibility and the exponent in cooperation with the repulsion
at Cu-site. We also show that anomalous flux quantization occurs for
. The superconducting region is presented on a phase diagram of
vs. plane.Comment: 4 pages, RevTex + 5 PS figures include
Generic differential geometry of hyperbolic plane curves
We study hyperbolic invariants of hyperbolic plane curves as applications of the singularity theory of smooth function
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