275 research outputs found
Lymphoedema in patients with lentigo maligna treated with imiquimod: A long-term adverse effect
Cut and paste invariants of manifolds via algebraic K-theory
Recent work of Jonathan Campbell and Inna Zakharevich has focused on building machinery for studying scissors congruence problems via algebraic -theory, and applying these tools to studying the Grothendieck ring of varieties. In this paper we give a new application of their framework: we construct a -space that recovers the classical ("schneiden und kleben," German for "cut and paste") groups for manifolds on , and we construct a derived version of the Euler characteristic
Horizontal supergranule-scale motions inferred from TRACE ultraviolet observations of the chromosphere
We study horizontal supergranule-scale motions revealed by TRACE observation
of the chromospheric emission, and investigate the coupling between the
chromosphere and the underlying photosphere. A highly efficient
feature-tracking technique called balltracking has been applied for the first
time to the image sequences obtained by TRACE (Transition Region and Coronal
Explorer) in the passband of white light and the three ultraviolet passbands
centered at 1700 {\AA}, 1600 {\AA}, and 1550 {\AA}. The resulting velocity
fields have been spatially smoothed and temporally averaged in order to reveal
horizontal supergranule-scale motions that may exist at the emission heights of
these passbands. We find indeed a high correlation between the horizontal
velocities derived in the white-light and ultraviolet passbands. The horizontal
velocities derived from the chromospheric and photospheric emission are
comparable in magnitude. The horizontal motions derived in the UV passbands
might indicate the existence of a supergranule-scale magnetoconvection in the
chromosphere, which may shed new light on the study of mass and energy supply
to the corona and solar wind at the height of the chromosphere. However, it is
also possible that the apparent motions reflect the chromospheric brightness
evolution as produced by acoustic shocks which might be modulated by the
photospheric granular motions in their excitation process, or advected partly
by the supergranule-scale flow towards the network while propagating upward
from the photosphere. To reach a firm conclusion, it is necessary to
investigate the role of granular motions in the excitation of shocks through
numerical modeling, and future high-cadence chromospheric magnetograms must be
scrutinized.Comment: 5 figures, accepted by Astronomy & Astrophysic
Biosynthesis of normal and low-molecular-mass complement component C1q by cultured human monocytes and macrophages
The Missing Luminous Blue Variables and the Bistability Jump
We discuss an interesting feature of the distribution of luminous blue
variables on the H-R diagram, and we propose a connection with the bistability
jump in the winds of early-type supergiants. There appears to be a deficiency
of quiescent LBVs on the S Dor instability strip at luminosities between log
L/Lsun = 5.6 and 5.8. The upper boundary, is also where the
temperature-dependent S Dor instability strip intersects the bistability jump
at about 21,000 K. Due to increased opacity, winds of early-type supergiants
are slower and denser on the cool side of the bistability jump, and we
postulate that this may trigger optically-thick winds that inhibit quiescent
LBVs from residing there. We conduct numerical simulations of radiation-driven
winds for a range of temperatures, masses, and velocity laws at log L/Lsun=5.7
to see what effect the bistability jump should have. We find that for
relatively low stellar masses the increase in wind density at the bistability
jump leads to the formation of a modest to strong pseudo photosphere -- enough
to make an early B-type star appear as a yellow hypergiant. Thus, the proposed
mechanism will be most relevant for LBVs that are post-red supergiants. Yellow
hypergiants like IRC+10420 and rho Cas occupy the same luminosity range as the
``missing'' LBVs, and show apparent temperature variations at constant
luminosity. If these yellow hypergiants do eventually become Wolf-Rayet stars,
we speculate that they may skip the normal LBV phase, at least as far as their
apparent positions on the HR diagram are concerned.Comment: 20 pages, 4 figs, accepted by Ap
New developments in ICRF antennas and non-traditional applications of HF power on TEXTOR
This paper reviews the present status of new developments in ICRF antennas, recent results on more realistic modeling of ICRF antennas using the 3-D full electromagnetic code ICANT and, finally, the latest development in the scenarios of non-traditional applications of HF power for wall conditioning
In vivo biocompatibility assessment of (PTFE–PVDF–PP) terpolymer-based membrane with potential application for glaucoma treatment
The aim of the work was to evaluate the in vivo biological behaviour of polymeric membrane materials for glaucoma implants. The base material was biostable synthetic terpolymer (PTFE–PVDF–PP) with proved biocompability (PN-EN ISO 10993). The samples manufactured in the form a membrane were subjected to chemical and physical treatment to create an open pore system within the polymer matrix. As a porogenic phase biodegradable natrium alginate in a fibrous form was employed. The non-perforating deep sclerectomy technique was performed in a rabbit model. The clinical observations were made after 14 and 30 days. During the study clinical symptoms of a moderate degree were observed, and histopathological changes were typical for foreign body implantation. At the end stage of the study no significant difference in histopathological assessment was found between control and experimental group. Similarities observed in both groups and relatively mild histopathological changes in the tissue surrounding the implant indicate that the observed symptoms come from a deep scleral trauma caused by surgery, and not by the presence of the implant itself
DOT Tomography of the Solar Atmosphere VII. Chromospheric Response to Acoustic Events
We use synchronous movies from the Dutch Open Telescope sampling the
G band, Ca II and Halpha with five-wavelength profile sampling to study the
response of the chromosphere to acoustic events in the underlying photosphere.
We first compare the visibility of the chromosphere in Ca II H and Halpha,
demonstrate that studying the chromosphere requires Halpha data, and summarize
recent developments in understanding why this is so. We construct divergence
and vorticity maps of the photospheric flow field from the G-band images and
locate specific events through the appearance of bright Ca II H grains. The
reaction of the Halpha chromosphere is diagnosed in terms of brightness and
Doppler shift. We show and discuss three particular cases in detail: a regular
acoustic grain marking shock excitation by granular dynamics, a persistent
flasher which probably marks magnetic-field concentration, and an exploding
granule. All three appear to buffet overlying fibrils, most clearly in
Dopplergrams. Although our diagnostic displays to dissect these phenomena are
unprecedentedly comprehensive, adding even more information (photospheric
Doppler tomography and magnetograms, chromospheric imaging and Doppler mapping
in the ultraviolet) is warranted.Comment: accepted by Solar Physic
A High-Quality Bonobo Genome Refines The Analysis Of Hominid Evolution
The divergence of chimpanzee and bonobo provides one of the few examples of recent hominid speciation(1,2). Here we describe a fully annotated, high-quality bonobo genome assembly, which was constructed without guidance from reference genomes by applying a multiplatform genomics approach. We generate a bonobo genome assembly in which more than 98% of genes are completely annotated and 99% of the gaps are closed, including the resolution of about half of the segmental duplications and almost all of the full-length mobile elements. We compare the bonobo genome to those of other great apes(1,3-5) and identify more than 5,569 fixed structural variants that specifically distinguish the bonobo and chimpanzee lineages. We focus on genes that have been lost, changed in structure or expanded in the last few million years of bonobo evolution. We produce a high-resolution map of incomplete lineage sorting and estimate that around 5.1% of the human genome is genetically closer to chimpanzee or bonobo and that more than 36.5% of the genome shows incomplete lineage sorting if we consider a deeper phylogeny including gorilla and orangutan. We also show that 26% of the segments of incomplete lineage sorting between human and chimpanzee or human and bonobo are non-randomly distributed and that genes within these clustered segments show significant excess of amino acid replacement compared to the rest of the genome
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