629 research outputs found
Asymptotic analysis of operator families and applications to resonant media
We give an overview of operator-theoretic tools that have recently proved
useful in the analysis of boundary-value and transmission problems for
second-order partial differential equations, with a view to addressing, in
particular, the asymptotic behaviour of resolvents of physically motivated
parameter-dependent operator families. We demonstrate the links of this rich
area, on the one hand, to functional frameworks developed by S. N. Naboko and
his students, and on the other hand, to concrete applications of current
interest in the physics and engineering communities.Comment: 60 pages, 2 figures; a survey of recent results in the area, see also
arXiv:2010.13318, arXiv:1808.03961, arXiv:1703.06220, arXiv:1510.0336
Tia1 dependent regulation of mRNA subcellular location and translation controls p53 expression in B cells.
Post-transcriptional regulation of cellular mRNA is essential for protein synthesis. Here we describe the importance of mRNA translational repression and mRNA subcellular location for protein expression during B lymphocyte activation and the DNA damage response. Cytoplasmic RNA granules are formed upon cell activation with mitogens, including stress granules that contain the RNA binding protein Tia1. Tia1 binds to a subset of transcripts involved in cell stress, including p53 mRNA, and controls translational silencing and RNA granule localization. DNA damage promotes mRNA relocation and translation in part due to dissociation of Tia1 from its mRNA targets. Upon DNA damage, p53 mRNA is released from stress granules and associates with polyribosomes to increase protein synthesis in a CAP-independent manner. Global analysis of cellular mRNA abundance and translation indicates that this is an extended ATM-dependent mechanism to increase protein expression of key modulators of the DNA damage response.Sequestering mRNA in cytoplasmic stress granules is a mechanism for translational repression. Here the authors find that p53 mRNA, present in stress granules in activated B lymphocytes, is released upon DNA damage and is translated in a CAP-independent manner
Monte Carlo Modeling of Spin FETs Controlled by Spin-Orbit Interaction
A method for Monte Carlo simulation of 2D spin-polarized electron transport
in III-V semiconductor heterojunction FETs is presented. In the simulation, the
dynamics of the electrons in coordinate and momentum space is treated
semiclassically. The density matrix description of the spin is incorporated in
the Monte Carlo method to account for the spin polarization dynamics. The
spin-orbit interaction in the spin FET leads to both coherent evolution and
dephasing of the electron spin polarization. Spin-independent scattering
mechanisms, including optical phonons, acoustic phonons and ionized impurities,
are implemented in the simulation. The electric field is determined
self-consistently from the charge distribution resulting from the electron
motion. Description of the Monte Carlo scheme is given and simulation results
are reported for temperatures in the range 77-300 K.Comment: 18 pages, 7 figure
Slow Spin Relaxation in Two-Dimensional Electron Systems with Antidots
We report a Monte Carlo investigation of the effect of a lattice of antidots
on spin relaxation in twodimensional electron systems. The spin relaxation time
is calculated as a function of geometrical parameters describing the antidot
lattice, namely, the antidot radius and the distance between their centers. It
is shown that spin polarization relaxation can be efficiently suppressed by the
chaotic spatial motion due to the antidot lattice. This phenomenon offers a new
approach to spin coherence manipulation in spintronics devices.Comment: submitted to Phys. Rev.
Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR
Substantial experimental and theoretical efforts worldwide are devoted to
explore the phase diagram of strongly interacting matter. At LHC and top RHIC
energies, QCD matter is studied at very high temperatures and nearly vanishing
net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was
created at experiments at RHIC and LHC. The transition from the QGP back to the
hadron gas is found to be a smooth cross over. For larger net-baryon densities
and lower temperatures, it is expected that the QCD phase diagram exhibits a
rich structure, such as a first-order phase transition between hadronic and
partonic matter which terminates in a critical point, or exotic phases like
quarkyonic matter. The discovery of these landmarks would be a breakthrough in
our understanding of the strong interaction and is therefore in the focus of
various high-energy heavy-ion research programs. The Compressed Baryonic Matter
(CBM) experiment at FAIR will play a unique role in the exploration of the QCD
phase diagram in the region of high net-baryon densities, because it is
designed to run at unprecedented interaction rates. High-rate operation is the
key prerequisite for high-precision measurements of multi-differential
observables and of rare diagnostic probes which are sensitive to the dense
phase of the nuclear fireball. The goal of the CBM experiment at SIS100
(sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD
matter: the phase structure at large baryon-chemical potentials (mu_B > 500
MeV), effects of chiral symmetry, and the equation-of-state at high density as
it is expected to occur in the core of neutron stars. In this article, we
review the motivation for and the physics programme of CBM, including
activities before the start of data taking in 2022, in the context of the
worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal
Single-cell multi-omics analysis of the immune response in COVID-19
Peer reviewedPublisher PD
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The human body at cellular resolution: the NIH Human Biomolecular Atlas Program
Abstract: Transformative technologies are enabling the construction of three-dimensional maps of tissues with unprecedented spatial and molecular resolution. Over the next seven years, the NIH Common Fund Human Biomolecular Atlas Program (HuBMAP) intends to develop a widely accessible framework for comprehensively mapping the human body at single-cell resolution by supporting technology development, data acquisition, and detailed spatial mapping. HuBMAP will integrate its efforts with other funding agencies, programs, consortia, and the biomedical research community at large towards the shared vision of a comprehensive, accessible three-dimensional molecular and cellular atlas of the human body, in health and under various disease conditions
SC3: consensus clustering of single-cell RNA-seq data
Single-cell RNA-seq enables the quantitative characterization of cell types based on global transcriptome profiles. We present single-cell consensus clustering (SC3), a user-friendly tool for unsupervised clustering, which achieves high accuracy and robustness by combining multiple clustering solutions through a consensus approach (http://bioconductor.org/packages/SC3). We demonstrate that SC3 is capable of identifying subclones from the transcriptomes of neoplastic cells collected from patients.V.Y.K., T.A., A.Y. and M.H. are supported by Wellcome Trust Grants. K.N.N. is supported by the Wellcome Trust Strategic Award 'Single cell genomics of mouse gastrulation'. M.T.S. acknowledges support from FRS-FNRS; the Belgian Network DYSCO (Dynamical Systems, Control and Optimisation), funded by the Interuniversity Attraction Poles Programme initiated by the Belgian State Science Policy Office; and the ARC (Action de Recherche Concerte) on Mining and Optimization of Big Data Models, funded by the Wallonia-Brussels Federation. M.B. acknowledges support from EPSRC (grant EP/N014529/1). T.C. was funded through a core funded fellowship by the Sanger Institute and a Chancellor′s fellowship from the University of Edinburgh. K.K. and A.R.G. are supported by Bloodwise (grant ref. 13003), the Wellcome Trust (grant ref. 104710/Z/14/Z), the Medical Research Council, the Kay Kendall Leukaemia Fund, the Cambridge NIHR Biomedical Research Center, the Cambridge Experimental Cancer Medicine Centre, the Leukemia and Lymphoma Society of America (grant ref. 07037) and a core support grant from the Wellcome Trust and MRC to the Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute. W.R. was supported by BBSRC (grant ref. BB/K010867/1), the Wellcome Trust (grant ref. 095645/Z/11/Z), EU BLUEPRINT and EpiGeneSys
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