175 research outputs found
The human prostatic cancer cell line LNCaP and its derived sublines: An in vitro model for the study of androgen sensitivity
__Abstract_
The LNCaP-FGC (fast growing colony) cell line, a subline derived from the LNCaP cell line, shares all the main characteristics, including its androgen sensitivity, described for the parental line. A number of sublines originating from the FGC line were characterized with respect to their response to steroid-depleted medium and to the synthetic androgen R1881. The growth of FGC cells in DCC medium with 0.1 nM R1881 was stimulated 2–3-fold compared to growth in DCC medium only. FGC cells that were continuously grown in DCC medium did not die, but their growth rate was clearly slowed down, and the cells remained responsive to androgen. These cells, therefore, have the androgen-sensitive, rather than the androgen-dependent phenotype. As cells of the subline FGC-JB could not be maintained in DCC medium, these cells better represent the androgen-dependent cell type. In contrast to the FGC line, cells of the R line, grew equally well in medium with complete or DCC serum. Under none of these culture conditions, R cells could significantly be stimulated further with R1881. Further analysis of the LNCaP-FGC sublines should provide valuable information concerning the development of androgen resistance in human prostate cancer
Spinodal instabilities within BUU approach
Using a recently developed method for the inclusion of fluctuation in the BUU
dynamics, we study the self-consistent propagation of inherent thermal noise of
unstable nuclear matter. The large time behaviour of the evolving system
exhibits synergism between fluctuation and non-linearities in a universal
manner which manifest in the appearance of macroscopic structure in the average
description.Comment: 12 pages Revtex. Two figures, uuencoded, are enclosed in a separate
fil
The hyperfine transition in light muonic atoms of odd Z
The hyperfine (hf) transition rates for muonic atoms have been re-measured
for select light nuclei, using neutron detectors to evaluate the time
dependence of muon capture. For F = 5.6 (2)
s for the hf transition rate, a value which is considerably more
accurate than previous measurements. Results are also reported for Na, Al, P,
Cl, and K; that result for P is the first positive identification.Comment: 12 pages including 5 tables and 4 figures, RevTex, submitted to Phys.
Rev.
Towards a high precision calculation for the pion-nucleus scattering lengths
We calculate the leading isospin conserving few-nucleon contributions to pion
scattering on H, He, and He. We demonstrate that the strong
contributions to the pion-nucleus scattering lengths can be controlled
theoretically to an accuracy of a few percent for isoscalar nuclei and of 10%
for isovector nuclei. In particular, we find the -He scattering length
to be where the uncertainties are
due to ambiguities in the -N scattering lengths and few-nucleon effects,
respectively. To establish this accuracy we need to identify a suitable power
counting for pion-nucleus scattering. For this purpose we study the dependence
of the two-nucleon contributions to the scattering length on the binding energy
of H. Furthermore, we investigate the relative size of the leading two-,
three-, and four-nucleon contributions. For the numerical evaluation of the
pertinent integrals, aMonte Carlo method suitable for momentum space is
devised. Our results show that in general the power counting suggested by
Weinberg is capable to properly predict the relative importance of -nucleon
operators, however, it fails to capture the relative strength of - and
-nucleon operators, where we find a suppression by a factor of 5
compared to the predicted factor of 50. The relevance for the extraction of the
isoscalar -N scattering length from pionic H and He is discussed.
As a side result, we show that beyond the calculation of the -H
scattering length is already beyond the range of applicability of heavy pion
effective field theory.Comment: 24 pages, 14 figures, 10 table
Hall-conductivity sign change and fluctuations in amorphous NbGe films
The sign change in the Hall conductivity has been studied in thin amorphous
NbGe0.3) films. By changing the film thickness it is
shown that the field at which the sign reversal occurs shifts to lower values
(from above to below the mean-field transition field ) with increasing
film thickness. This effect can be understood in terms of a competition between
a positive normal and a negative fluctuation contribution to the Hall
conductivity.Comment: 5 pages, 4 figures, to appear in Phys. Rev.
Proton Differential Elliptic Flow and the Isospin-Dependence of the Nuclear Equation of State
Within an isospin-dependent transport model for nuclear reactions involving
neutron-rich nuclei, we study the first-order direct transverse flow of protons
and their second-order differential elliptic flow as a function of transverse
momentum. It is found that the differential elliptic flow of mid-rapidity
protons, especially at high transverse momenta, is much more sensitive to the
isospin dependence of the nuclear equation of state than the direct flow.
Origins of these different sensitivities and their implications to the
experimental determination of the isospin dependence of the nuclear equation of
state by using neutron-rich heavy-ion collisions at intermediate energies are
discussed.Comment: 15 pages, 6 figures. Phys. Rev. C (2001) in pres
Atmospheric Heating and Wind Acceleration: Results for Cool Evolved Stars based on Proposed Processes
A chromosphere is a universal attribute of stars of spectral type later than
~F5. Evolved (K and M) giants and supergiants (including the zeta Aurigae
binaries) show extended and highly turbulent chromospheres, which develop into
slow massive winds. The associated continuous mass loss has a significant
impact on stellar evolution, and thence on the chemical evolution of galaxies.
Yet despite the fundamental importance of those winds in astrophysics, the
question of their origin(s) remains unsolved. What sources heat a chromosphere?
What is the role of the chromosphere in the formation of stellar winds? This
chapter provides a review of the observational requirements and theoretical
approaches for modeling chromospheric heating and the acceleration of winds in
single cool, evolved stars and in eclipsing binary stars, including physical
models that have recently been proposed. It describes the successes that have
been achieved so far by invoking acoustic and MHD waves to provide a physical
description of plasma heating and wind acceleration, and discusses the
challenges that still remain.Comment: 46 pages, 9 figures, 1 table; modified and unedited manuscript;
accepted version to appear in: Giants of Eclipse, eds. E. Griffin and T. Ake
(Berlin: Springer
A Game-Theoretic approach to Fault Diagnosis of Hybrid Systems
Physical systems can fail. For this reason the problem of identifying and
reacting to faults has received a large attention in the control and computer
science communities. In this paper we study the fault diagnosis problem for
hybrid systems from a game-theoretical point of view. A hybrid system is a
system mixing continuous and discrete behaviours that cannot be faithfully
modeled neither by using a formalism with continuous dynamics only nor by a
formalism including only discrete dynamics. We use the well known framework of
hybrid automata for modeling hybrid systems, and we define a Fault Diagnosis
Game on them, using two players: the environment and the diagnoser. The
environment controls the evolution of the system and chooses whether and when a
fault occurs. The diagnoser observes the external behaviour of the system and
announces whether a fault has occurred or not. Existence of a winning strategy
for the diagnoser implies that faults can be detected correctly, while
computing such a winning strategy corresponds to implement a diagnoser for the
system. We will show how to determine the existence of a winning strategy, and
how to compute it, for some decidable classes of hybrid automata like o-minimal
hybrid automata.Comment: In Proceedings GandALF 2011, arXiv:1106.081
Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy
We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and
Space Scienc
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