1,645 research outputs found
SPARCCS Smart Phone Assisted Rapid Command and Control System (Poster)
Military Wireless Communications (MWC)Military Wireless Communications (MWC
Searching for galaxy clusters in the VST-KiDS Survey
We present the methods and first results of the search for galaxy clusters in
the Kilo Degree Survey (KiDS). The adopted algorithm and the criterium for
selecting the member galaxies are illustrated. Here we report the preliminary
results obtained over a small area (7 sq. degrees), and the comparison of our
cluster candidates with those found in the RedMapper and SZ Planck catalogues;
the analysis to a larger area (148 sq. degrees) is currently in progress. By
the KiDS cluster search, we expect to increase the completeness of the clusters
catalogue to z = 0.6-0.7 compared to RedMapper.Comment: 5 pages, 4 figures, to be published in the Proceedings of the
Conference "The Universe of Digital Sky Surveys", Naples, November 25-28 201
A 120-Mpc Periodicity in the Three-Dimensional Distribution of Galaxy Superclusters
Using a new compilation of available data on galaxy clusters and
superclusters we present evidence for a quasiregular three-dimensional network
of rich superclusters and voids, with the regions of high density separated by
about 120 Mpc. We calculate the power spectrum for clusters of galaxies; it has
a peak on the wavelength equal to the step of the network; the excess in the
amplitude of the spectrum over that of the cold dark matter model is by a
factor of 1.4. The probability that the spectrum can be formed within the
framework of the standard cosmogony is very small. If the cluster distribution
reflects the distribution of all matter (luminous and dark), then there must
exists some hithero unknown process that produces regular structure on large
scales.Comment: Tex, 6 pages, 2 PostScript figures embedded, accepted by Nature on
November 19, 199
Evidence for high inter-granular current flow in single-phase polycrystalline MgB2 superconductor
The distribution of magnetic field in single-phase polycrystalline bulk MgB2
has been measured using a Magneto-Optical (MO) technique for an external
magnetic field applied perpendicular to the sample surface. The MO studies
indicate that an inter-granular current network is readily established in this
material and the current is not limited by weak-linked grain boundaries. The
grain boundaries are observed to resist preferential magnetic field
penetration, with the inter-grain mechanism dominating the current flow in the
sample at temperatures up to 30K. The results provide clear evidence that the
intra-granular current flow is isotropic. A critical current density of ~10^4
Acm-2 was estimated at 30K in a field of 150mT from the MO measurements. These
results provide further evidence of the considerable potential for MgB2 for
engineering applications.Comment: 3 pages, 3 figure
Differentially Addressable Cavities within Metal-Organic Cage-Cross-Linked Polymeric Hydrogels
Here we report a new class of hydrogels formed by polymers that are cross-linked through subcomponent self-assembled metal–organic cages. Selective encapsulation of guest molecules within the cages creates two distinct internal phases within the hydrogel, which allows for contrasting release profiles of related molecules depending on their aptitude for encapsulation within the cages. The hydrogels were fabricated into microparticles via a droplet-based microfluidic approach and proved responsive to a variety of stimuli, including acid and competing amine or aldehyde subcomponents, allowing for the triggered release of cargo
MEKK4 Is an Effector of the Embryonic TRAF4 for JNK Activation
TRAF4 has previously been shown to activate JNK through an unknown mechanism. Here, we show that endogenous TRAF4 and MEKK4 associate in both human K562 cells and mouse E10.5 embryos. TRAF4 interacts with the kinase domain of MEKK4. However, this association does not require MEKK4 kinase activity. The interaction of MEKK4 and TRAF4 are further demonstrated by the colocalization of TRAF4 and MEKK4 in cells. Importantly, although TRAF4 has little or no ability to activate JNK independently, coexpression of TRAF4 and MEKK4 results in synergistic activation of JNK that is inhibited by a kinase-inactive mutant of MEKK4, MEKK4K1361R. MEKK4 binds the TRAF domain of TRAF4 and MEKK4/TRAF4 activation of JNK is inhibited by expression of the TRAF domain. Furthermore, TRAF4 stimulates MEKK4 kinase activity by promoting MEKK4 oligomerization and JNK activation can be stimulated by chemical induction of MEKK4 dimerization. The findings identify MEKK4 as the MAPK kinase kinase for TRAF4 regulation of the JNK pathway
Eccentric black hole-neutron star mergers: effects of black hole spin and equation of state
There is a high level of interest in black hole-neutron star binaries, not
only because their mergers may be detected by gravitational wave observatories
in the coming years, but also because of the possibility that they could
explain a class of short duration gamma-ray bursts. We study black hole-neutron
star mergers that occur with high eccentricity as may arise from dynamical
capture in dense stellar regions such as nuclear or globular clusters. We
perform general relativistic simulations of binaries with a range of impact
parameters, three different initial black hole spins (zero, aligned and
anti-aligned with the orbital angular momentum), and neutron stars with three
different equations of state. We find a rich diversity across these parameters
in the resulting gravitational wave signals and matter dynamics, which should
also be reflected in the consequent electromagnetic emission. Before tidal
disruption, the gravitational wave emission is significantly larger than
perturbative predictions suggest for periapsis distances close to effective
innermost stable separations, exhibiting features reflecting the zoom-whirl
dynamics of the orbit there. Guided by the simulations, we develop a simple
model for the change in orbital parameters of the binary during close
encounters. Depending upon the initial parameters of the system, we find that
mass transfer during non-merging close encounters can range from essentially
zero to a sizable fraction of the initial neutron star mass. The same holds for
the amount of material outside the black hole post-merger, and in some cases
roughly half of this material is estimated to be unbound. We also see that
non-merging close encounters generically excite large oscillations in the
neutron star that are qualitatively consistent with f-modes.Comment: 19 pages, 13 figures, revised according to referee comment
Microstructure and superconducting properties of hot isostatically pressed MgB2
Bulk samples of MgB2 have been formed by hot isostatic pressing (HIPping) of
commercial powder at 100MPa and 950=B0C. The resulting material is 100% dense
with a sharp superconducting transition at 37.5K. Microstructural studies have
indicated the presence of small amounts of second phases within the material,
namely MgO and B rich compositions, probably MgB4. Magnetisation measurements
performed at 20K have revealed values of Jc=1.3 x 106A/cm2 at zero field, and
9.3 x 105A/cm2 at 1T. Magneto optical (MO) studies have shown direct evidence
for the superconducting homogeneity and strong intergranular current flow in
the material.Comment: 3 pages, 6 figures, text updated, new references included and
discussed. Submitted to Superconductor Science and Technolog
MAP3K4 Controls the Chromatin Modifier HDAC6 during Trophoblast Stem Cell Epithelial-to-Mesenchymal Transition
The first epithelial-to-mesenchymal transition (EMT) occurs in trophoblast stem (TS) cells during implantation. Inactivation of the serine/threonine kinase MAP3K4 in TS cells (TSKI4 cells) induces an intermediate state of EMT, where cells retain stemness, lose epithelial markers, and gain mesenchymal characteristics. Investigation of relationships among MAP3K4 activity, stemness, and EMT in TS cells may reveal key regulators of EMT. Here, we show that MAP3K4 activity controls EMT through the ubiquitination and degradation of HDAC6. Loss of MAP3K4 activity in TSKI4 cells results in elevated HDAC6 expression and the deacetylation of cytoplasmic and nuclear targets. In the nucleus, HDAC6 deacetylates the promoters of tight junction genes, promoting the dissolution of tight junctions. Importantly, HDAC6 knockdown in TSKI4 cells restores epithelial features, including cell-cell adhesion and barrier formation. These data define a role for HDAC6 in regulating gene expression during transitions between epithelial and mesenchymal phenotypes
A spectroscopic study of NGC 6251 and its companion galaxies
Measurements of the velocities of galaxies thought to be associated with the
giant radio galaxy NGC 6251 confirm the presence of a poor cluster with a
systemic redshift of z= 0.0244 +/- 0.0004 and a line-of-sight velocity
dispersion of sigma_{z}= 283 (+109, -52) km/s. This suggests a cluster
atmosphere temperature of T = 0.7 (+0.6, -0.2) keV, which is not enough to
confine the radio jet by gas pressure. The core of NGC 6251 shows strong
emission lines of [O III] and H alpha + [N II], but there is no evidence for
line emission from the jet (detected in optical continuum by Keel (1988)).Comment: 7 pages, 2 figures, to be published in MNRA
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