32,311 research outputs found
Phase structures of the black D-D-brane system in various ensembles II: electrical and thermodynamic stability
By incorporating the electrical stability condition into the discussion, we
continue the study on the thermodynamic phase structures of the D-D
black brane in GG, GC, CG, CC ensembles defined in our previous paper
arXiv:1502.00261. We find that including the electrical stability conditions in
addition to the thermal stability conditions does not modify the phase
structure of the GG ensemble but puts more constraints on the parameter space
where black branes can stably exist in GC, CG, CC ensembles. In particular, the
van der Waals-like phase structure which was supposed to be present in these
ensembles when only thermal stability condition is considered would no longer
be visible, since the phase of the small black brane is unstable under
electrical fluctuations. However, the symmetry of the phase structure by
interchanging the two kinds of brane charges and potentials is still preserved,
which is argued to be the result of T-duality.Comment: 34 pages, 17 figure
Phase structures of the black D-D-brane system in various ensembles I: thermal stability
When the D-brane () with delocalized D charges is put into
equilibrium with a spherical thermal cavity, the two kinds of charges can be
put into canonical or grand canonical ensemble independently by setting
different conditions at the boundary. Using the thermal stability condition, we
discuss the phase structures of various ensembles of this system formed in this
way and find out the situations that the black brane could be the final stable
phase in these ensembles. In particular, van der Waals-like phase transitions
can happen when D0 and D4 charges are in different kinds of ensembles.
Furthermore, our results indicate that the D-branes and the delocalized
D-branes are equipotent.Comment: 45 pages, 16 figures, accepted by JHEP; A section added to briefly
discuss more general stability conditions, various typos correcte
A multi-phenotypic cancer model with cell plasticity
The conventional cancer stem cell (CSC) theory indicates a hierarchy of CSCs
and non-stem cancer cells (NSCCs), that is, CSCs can differentiate into NSCCs
but not vice versa. However, an alternative paradigm of CSC theory with
reversible cell plasticity among cancer cells has received much attention very
recently. Here we present a generalized multi-phenotypic cancer model by
integrating cell plasticity with the conventional hierarchical structure of
cancer cells. We prove that under very weak assumption, the nonlinear dynamics
of multi-phenotypic proportions in our model has only one stable steady state
and no stable limit cycle. This result theoretically explains the phenotypic
equilibrium phenomena reported in various cancer cell lines. Furthermore,
according to the transient analysis of our model, it is found that cancer cell
plasticity plays an essential role in maintaining the phenotypic diversity in
cancer especially during the transient dynamics. Two biological examples with
experimental data show that the phenotypic conversions from NCSSs to CSCs
greatly contribute to the transient growth of CSCs proportion shortly after the
drastic reduction of it. In particular, an interesting overshooting phenomenon
of CSCs proportion arises in three-phenotypic example. Our work may pave the
way for modeling and analyzing the multi-phenotypic cell population dynamics
with cell plasticity.Comment: 29 pages,6 figure
Miniature High-Sensitivity High-Temperature Fiber Sensor with a Dispersion Compensation Fiber-Based Interferometer
A miniature high-sensitivity, high-temperature fiber sensor with an interferometer based on a bare small-core-diameter dispersion compensation fiber (DCF) is reported. The sensing head is a single-mode-fiber (SMF) DCF configuration formed by a 4 mm long bare DCF with one end connected to the SMF by a fusion splicing technique and the other end cleaved. Due to the large mode index difference and high thermo-optic coefficient induced by two dominative interference modes, a miniature high-temperature fiber sensor with a high sensitivity of 68.6 pm/°C is obtained by monitoring the wavelength shift of the interference spectrum. This type of sensor has the features of small size, high sensitivity, high stability, simple structure, and low cost
- …