Sparse Recovery with Very Sparse Compressed Counting

Compressed sensing (sparse signal recovery) often encounters nonnegative data (e.g., images). Recently we developed the methodology of using (dense) Compressed Counting for recovering nonnegative K-sparse signals. In this paper, we adopt very sparse Compressed Counting for nonnegative signal recovery. Our design matrix is sampled from a maximally-skewed p-stable distribution (0<p<1), and we sparsify the design matrix so that on average (1-g)-fraction of the entries become zero. The idea is related to very sparse stable random projections (Li et al 2006 and Li 2007), the prior work for estimating summary statistics of the data. In our theoretical analysis, we show that, when p->0, it suffices to use M= K/(1-exp(-gK) log N measurements, so that all coordinates can be recovered in one scan of the coordinates. If g = 1 (i.e., dense design), then M = K log N. If g= 1/K or 2/K (i.e., very sparse design), then M = 1.58K log N or M = 1.16K log N. This means the design matrix can be indeed very sparse at only a minor inflation of the sample complexity. Interestingly, as p->1, the required number of measurements is essentially M = 2.7K log N, provided g= 1/K. It turns out that this result is a general worst-case bound

Quantum molecular dynamics simulations of the thermophysical properties of shocked liquid ammonia for pressures up to 1.3 TPa

We investigate via quantum molecular-dynamics simulations the thermophysical properties of shocked liquid ammonia up to the pressure 1.3 TPa and temperature 120000 K. The principal Hugoniot is predicted from wide-range equation of state, which agrees well with available experimental measurements up to 64 GPa. Our systematic study of the structural properties demonstrates that liquid ammonia undergoes a gradual phase transition along the Hugoniot. At about 4800 K, the system transforms into a metallic, complex mixture state consisting of $\textnormal{N}\textnormal{H}_{3}$, $\textnormal{N}_{2}$, $\textnormal{H}_{2}$, N, and H. Furthermore, we discuss the implications for the interiors of Uranus and Neptune.Comment: 16 pages, 8 figures. arXiv admin note: text overlap with arXiv:1012.488

Pathogenetic role of tissue factor in graft-versus-host disease

Graft-versus-host disease (GVHD) is a serious complication after allogeneic stem cell transplantation, the mechanism of it is still not elucidated. Recent findings suggest that host endothelial cells are a target of alloreactive donor cytotoxic T lymphocytes in GVHD and tissue factor (TF) plays an important role not only in coagulation-inflammation cycle, but also in transplant immunology. We postulate TF expression in vascular endothelial cells(VEC) may play an pivotal role in the pathogenesis of GVHD. TF gene andprotein expression in target organs of GVHD in aGVHD mice was significantly elevated compared to that of controls as determined by real-time PCR and Western blotting. Allogeneic CD4^+^T cell and CD8^+^T cells enhanced TF, VCAM-1, TNF-[alpha], IFN-[gamma] and IL-6 expression in TNF-[alpha] prestimulated HUVECs compared to controls as determined by flowcytometry and real-time PCR. JNK and p38MAPK mediated allogeneic T cells-induced TF expression in HUVECs. These effects were largely prevented by monoclonal antibody against TF, SB203580 and SP600125. In concert, these data provide strong evidence that upregulated TF expression is related to tissue damage caused by GVHD, TF isthe key factor in GVHD mediated by endothelial cells and allogeneic T cells-induced TF and consecutive proinflammatory cytokines expression in VEC contribute to the pathogenesis of GVHD

Gravitating tensor monopole in a Lorentz-violating field theory

We present a solution of the coupled Einstein and rank-two antisymmetric tensor field equations where Lorentz symmetry is spontaneously broken, and we discuss its observational signatures. Especially, the deflection angles have important qualitative differences between tensor and scalar monopoles. If a monopole were to be detected, it would be discriminated whether or not to correspond to a tensor one. This phenomenon might open up new direction in the search of Lorentz violation with future astrophysical observations.Comment: 5 pages, 4 figure