3,017 research outputs found
Higher homotopy operations and cohomology
We explain how higher homotopy operations, defined topologically, may be
identified under mild assumptions with (the last of) the Dwyer-Kan-Smith
cohomological obstructions to rectifying homotopy-commutative diagrams.Comment: 28 page
Humanitarian Intervention, the Responsibility to Protect, and Sovereignty: Historical and Moral Reflections
Article published in the Michigan State International Law Review
On local-to-global spectral sequences for the cohomology of diagrams
The aim of this paper is to construct and examine three candidates for
local-to-global spectral sequences for the cohomology of diagrams of algebras
with directed indexing. In each case, the -terms can be viewed as a type
of local cohomology relative to a map or an object in the diagram.Comment: 27 pages; incorporated corrections based on referee's report and
added a few reference
On realizing diagrams of Pi-algebras
Given a diagram of Pi-algebras (graded groups equipped with an action of the
primary homotopy operations), we ask whether it can be realized as the homotopy
groups of a diagram of spaces. The answer given here is in the form of an
obstruction theory, of somewhat wider application, formulated in terms of
generalized Pi-algebras. This extends a program begun in [J. Pure Appl. Alg.
103 (1995) 167-188] and [Topology 43 (2004) 857-892] to study the realization
of a single Pi-algebra. In particular, we explicitly analyze the simple case of
a single map, and provide a detailed example, illustrating the connections to
higher homotopy operations.Comment: This is the version published by Algebraic & Geometric Topology on 21
June 200
Radio Emission from Young Supernovae and Supernova Remnants in Arp 299
We have made sensitive milliarcsecond-resolution radio images of the nearby
merger galaxy Arp 299 at four epochs spread over 18 months between 2003 and
2005. The combined data revealed a total of 30 point sources in the two primary
merger nuclei. Twenty-five of these are found in the northeastern nucleus
(component "A"=IC 694) over a region ~100 pc in diameter, while five are in the
southwestern nucleus (component "B1"=NGC 3690) within a region ~30 pc in size.
These objects are interpreted as young supernovae and supernova remnants; the
ratio of the source counts in nuclei A and B1 is approximately equal to the
ratio of their predicted supernova rates. An approximate luminosity function
has been derived for nucleus A, and indicates that it might contain as many as
500-1000 compact radio sources more powerful than Cas A; the integrated flux
density of these sources would be about 20% of the total flux density seen at
lower resolution. A new supernova occurred in nucleus B1 in the first half of
2005, having a peak radio power at least 2,000 times the present power of
Cassiopeia A. This supernova is located within 0.4 pc (projected distance) of
an apparently older supernova remnant, making it very likely that this
indicates the presence of a massive super star cluster within nucleus B1.
Comparison of the typical radio flux densities of our compact radio sources to
the observed X-ray luminosities of nuclei A and B1 indicates that it is
possible that one radio source in each nucleus actually could be associated
with an active galactic nucleus rather than being a supernova remnant.Comment: Astronomical Journal, in press, December 2009 issu
Preclinical Analysis of JAA-F11, a Specific Anti-Thomsen-Friedenreich Antibody via Immunohistochemistry and In Vivo Imaging.
The tumor specificity of JAA-F11, a novel monoclonal antibody specific for the Thomsen-Friedenreich cancer antigen (TF-Ag-alpha linked), has been comprehensively studied by in vitro immunohistochemical (IHC) staining of human tumor and normal tissue microarrays and in vivo biodistribution and imaging by micro-positron emission tomography imaging in breast and lung tumor models in mice. The IHC analysis detailed herein is the comprehensive biological analysis of the tumor specificity of JAA-F11 antibody performed as JAA-F11 is progressing towards preclinical safety testing and clinical trials. Wide tumor reactivity of JAA-F11, relative to the matched mouse IgG3 (control), was observed in 85% of 1269 cases of breast, lung, prostate, colon, bladder, and ovarian cancer. Staining on tissues from breast cancer cases was similar regardless of hormonal or Her2 status, and this is particularly important in finding a target on the currently untargetable triple-negative breast cancer subtype. Humanization of JAA-F11 was recently carried out as explained in a companion paper "Humanization of JAA-F11, a Highly Specific Anti-Thomsen-Friedenreich Pancarcinoma Antibody and In Vitro Efficacy Analysis" (Neoplasia 19: 716-733, 2017), and it was confirmed that humanization did not affect chemical specificity. IHC studies with humanized JAA-F11 showed similar binding to human breast tumor tissues. In vivo imaging and biodistribution studies in a mouse syngeneic breast cancer model and in a mouse-human xenograft lung cancer model with humanized 124I- JAA-F11 construct confirmed in vitro tumor reactivity and specificity. In conclusion, the tumor reactivity of JAA-F11 supports the continued development of JAA-F11 as a targeted cancer therapeutic for multiple cancers, including those with unmet need
Sustained Magnetorotational Turbulence in Local Simulations of Stratified Disks with Zero Net Magnetic Flux
We examine the effects of density stratification on magnetohydrodynamic
turbulence driven by the magnetorotational instability in local simulations
that adopt the shearing box approximation. Our primary result is that, even in
the absence of explicit dissipation, the addition of vertical gravity leads to
convergence in the turbulent energy densities and stresses as the resolution
increases, contrary to results for zero net flux, unstratified boxes. The ratio
of total stress to midplane pressure has a mean of ~0.01, although there can be
significant fluctuations on long (>~50 orbit) timescales. We find that the time
averaged stresses are largely insensitive to both the radial or vertical aspect
ratio of our simulation domain. For simulations with explicit dissipation, we
find that stratification extends the range of Reynolds and magnetic Prandtl
numbers for which turbulence is sustained. Confirming the results of previous
studies, we find oscillations in the large scale toroidal field with periods of
~10 orbits and describe the dynamo process that underlies these cycles.Comment: 13 pages, 18 figures, submitted to Ap
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