15,208 research outputs found
Algebraic -theory of planar cuspidal curves
In this paper, we evaluate the algebraic -groups of a planar cuspidal
curve over a perfect -algebra relative to the cusp point. A
conditional calculation of these groups was given earlier by Hesselholt,
assuming a conjecture on the structure of certain polytopes. Our calculation
here, however, is unconditional and illustrates the advantage of the new setup
for topological cyclic homology by Nikolaus-Scholze, which is used throughout.
The only input necessary for our calculation is the evaluation by the Buenos
Aires Cyclic Homology group and by Larsen of the structure of Hochschild
complex of the coordinate ring as a mixed complex, that is, as an object of the
infinity category of chain complexes with circle action.Comment: 9 page
Immunotherapy of invasive fungal infection in hematopoietic stem cell transplant recipients
Despite the availability of new antifungal compounds, invasive fungal infection remains a significant cause of morbidity and mortality in children and adults undergoing allogeneic hematopoietic stem cell transplantation (HSCT). Allogeneic HSCT recipients suffer from a long lasting defect of different arms of the immune system, which increases the risk for and deteriorates the prognosis of invasive fungal infections. In turn, advances in understanding these immune deficits have resulted in promising strategies to enhance or restore critical immune functions in allogeneic HSCT recipients. Potential approaches include the administration of granulocytes, since neutropenia is the single most important risk factor for invasive fungal infection, and preliminary clinical results suggest a benefit of adoptively transferred donor-derived antifungal T cells. In vitro data and animal studies demonstrate an antifungal effect of natural killer cells, but clinical data are lacking to date. This review summarizes and critically discusses the available data of immunotherapeutic strategies in allogeneic HSCT recipients suffering from invasive fungal infection
Lipid ion channels and the role of proteins
Synthetic lipid membranes in the absence of proteins can display quantized
conduction events for ions that are virtually indistinguishable from those of
protein channel. By indistinguishable we mean that one cannot decide based on
the current trace alone whether conductance events originate from a membrane,
which does or does not contain channel proteins. Additional evidence is
required to distinguish between the two cases, and it is not always certain
that such evidence can be provided. The phenomenological similarities are
striking and span a wide range of phenomena: The typical conductances are of
equal order and both lifetime distributions and current histograms are similar.
One finds conduction bursts, flickering, and multistep-conductance. Lipid
channels can be gated by voltage, and can be blocked by drugs. They respond to
changes in lateral membrane tension and temperature. Thus, they behave like
voltage-gated, temperature-gated and mechano-sensitive protein channels, or
like receptors. Lipid channels are remarkably under-appreciated. However, the
similarity between lipid and protein channels poses an eminent problem for the
interpretation of protein channel data. For instance, the Hodgkin-Huxley theory
for nerve pulse conduction requires a selective mechanism for the conduction of
sodium and potassium ions. To this end, the lipid membrane must act both as a
capacitor and as an insulator. Non-selective ion conductance by mechanisms
other than the gated protein-channels challenges the proposed mechanism for
pulse propagation. ... Some important questions arise: Are lipid and protein
channels similar due a common mechanism, or are these similarities fortuitous?
Is it possible that both phenomena are different aspects of the same
phenomenon? Are lipid and protein channels different at all? ... (abbreviated)Comment: 10 pages, 10 figures - accepted by 'Accounts of Chemical Research
Deep Convolutional Neural Networks as Generic Feature Extractors
Recognizing objects in natural images is an intricate problem involving
multiple conflicting objectives. Deep convolutional neural networks, trained on
large datasets, achieve convincing results and are currently the
state-of-the-art approach for this task. However, the long time needed to train
such deep networks is a major drawback. We tackled this problem by reusing a
previously trained network. For this purpose, we first trained a deep
convolutional network on the ILSVRC2012 dataset. We then maintained the learned
convolution kernels and only retrained the classification part on different
datasets. Using this approach, we achieved an accuracy of 67.68 % on CIFAR-100,
compared to the previous state-of-the-art result of 65.43 %. Furthermore, our
findings indicate that convolutional networks are able to learn generic feature
extractors that can be used for different tasks.Comment: 4 pages, accepted version for publication in Proceedings of the IEEE
International Joint Conference on Neural Networks (IJCNN), July 2015,
Killarney, Irelan
Hertz potentials and asymptotic properties of massless fields
In this paper we analyze Hertz potentials for free massless spin-s fields on
the Minkowski spacetime, with data in weighted Sobolev spaces. We prove
existence and pointwise estimates for the Hertz potentials using a weighted
estimate for the wave equation. This is then applied to give weighted estimates
for the solutions of the spin-s field equations, for arbitrary half-integer s.
In particular, the peeling properties of the free massless spin-s fields are
analyzed for initial data in weighted Sobolev spaces with arbitrary,
non-integer weights.Comment: Regularity assumptions corrected. Orthogonality condition eliminate
HD 49798: Its History of Binary Interaction and Future Evolution
The bright subdwarf-O star (sdO), HD 49798, is in a 1.55 day orbit with a
compact companion that is spinning at 13.2 seconds. Using the measurements of
the effective temperature (), surface gravity (), and
surface abundances of the sdO, we construct models to study the evolution of
this binary system using Modules for Experiments in Stellar Astrophysics
(). Previous studies of the compact companion have disagreed on
whether it is a white dwarf (WD) or a neutron star (NS). From the published
measurements of the companion's spin and spin-up rate, we agree with Mereghetti
and collaborators that a NS companion is more likely. However, since there
remains the possibility of a WD companion, we use our constructed
models to run simulations with both WD and NS companions that
help us constrain the past and future evolution of this system. If it presently
contains a NS, the immediate mass transfer evolution upon Roche lobe (RL)
filling will lead to mass transfer rates comparable to that implied in
ultraluminous X-ray sources (ULXs). Depending on the rate of angular momentum
extraction via a wind, the fate of this system is either a wide ( day) intermediate mass binary pulsar (IMPB) with a relatively
rapidly spinning NS ( s) and a high mass WD (), or a solitary millisecond pulsar (MSP).Comment: 6 pages, 4 figure
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