1,253 research outputs found
In vivo imaging of the tonoplast intrinsic protein family in Arabidopsis roots
Background: Tonoplast intrinsic proteins (TIPs) are widely used as markers for vacuolar
compartments in higher plants. Ten TIP isoforms are encoded by the Arabidopsis genome. For
several isoforms, the tissue and cell specific pattern of expression are not known.
Results: We generated fluorescent protein fusions to the genomic sequences of all members of
the Arabidopsis TIP family whose expression is predicted to occur in root tissues (TIP1;1 and 1;2;
TIP2;1, 2;2 and 2;3; TIP4;1) and expressed these fusions, both individually and in selected pairwise
combinations, in transgenic Arabidopsis. Analysis by confocal microscopy revealed that TIP
distribution varied between different cell layers within the root axis, with extensive co-expression
of some TIPs and more restricted expression patterns for other isoforms. TIP isoforms whose
expression overlapped appeared to localise to the tonoplast of the central vacuole, vacuolar bulbs
and smaller, uncharacterised structures.
Conclusion: We have produced a comprehensive atlas of TIP expression in Arabidopsis roots,
which reveals novel expression patterns for not previously studied TIPs
Integral Foliated Simplicial Volume of Aspherical Manifolds
We consider the relation between simplicial volume and two of its variants: the stable integral simplicial volume and the integral foliated simplicial volume. The definition of the latter depends on a choice of a measure preserving action of the fundamental group on a probability space. We show that integral foliated simplicial volume is monotone with respect to weak containment of measure preserving actions and yields upper bounds on (integral) homology growth. Using ergodic theory we prove that simplicial volume, integral foliated simplicial volume and stable integral simplicial volume coincide for closed hyperbolic 3-manifolds and closed aspherical manifolds with amenable residually finite fundamental group (being equal to zero in the latter case). However, we show that integral foliated simplicial volume and the classical simplicial volume do not coincide for hyperbolic manifolds of dimension at least 4
A constant dark matter halo surface density in galaxies
We confirm and extend the recent finding that the central surface density
r_0*rho_0 galaxy dark matter halos, where r_0 and rho_0 are the halo core
radius and central density, is nearly constant and independent of galaxy
luminosity. Based on the co-added rotation curves of about 1000 spiral
galaxies, mass models of individual dwarf irregular and spiral galaxies of late
and early types with high-quality rotation curves and, galaxy-galaxy weak
lensing signals from a sample of spiral and elliptical galaxies, we find that
log(r_0*rho_0) = 2.15 +- 0.2, in units of log(Msol/pc^2). We also show that the
observed kinematics of Local Group dwarf spheroidal galaxies are consistent
with this value. Our results are obtained for galactic systems spanning over 14
magnitudes, belonging to different Hubble Types, and whose mass profiles have
been determined by several independent methods. In the same objects, the
approximate constancy of rho_0*r_0 is in sharp contrast to the systematical
variations, by several orders of magnitude, of galaxy properties, including
rho_0 and central stellar surface density.Comment: Accepted for publication in MNRAS. 9 pages, 4 figure
Pharmacological treatment of hypertrophic cardiomyopathy: current practice and novel perspectives
Non-Standard neutral kaons dynamics from D-brane statistics
The neutral kaon system can be effectively described by non-unitary,
dissipative, completely positive dynamics that extend the usual treatment. In
the framework of open quantum systems, we show how the origin of these
non-standard time evolutions can be traced to the interaction of the kaon
system with a large environment. We find that D-branes, effectively described
by a heat-bath of quanta obeying infinite statistics, could constitute a
realistic example of such an environment.Comment: 14 pages, plain-TeX, no figure
Removing Ambiguities in the Neutrino Mass Matrix
We suggest that the weak-basis independent condition det(M_nu)=0 for the
effective neutrino mass matrix can be used in order to remove the ambiguities
in the reconstruction of the neutrino mass matrix from input data available
from present and future feasible experiments. In this framework, we study the
full reconstruction of M_nu with special emphasis on the correlation between
the Majorana CP-violating phase and the various mixing angles. The impact of
the recent KamLAND results on the effective neutrino mass parameter is also
briefly discussed.Comment: 11 pages, 4 figures. Comments and references added; final version to
appear in Phys. Lett.
On the weak-coupling limit and complete positivity
We consider two non-interacting systems embedded in a heat bath. If they
remain dynamically independent, physical inconsistencies are avoided only if
the single-system reduced dynamics is completely positive also beyond the
weak-coupling limit.Comment: 11 pages, plain-Te
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