Information Theoretic Limits for Standard and One-Bit Compressed Sensing with Graph-Structured Sparsity

In this paper, we analyze the information theoretic lower bound on the necessary number of samples needed for recovering a sparse signal under different compressed sensing settings. We focus on the weighted graph model, a model-based framework proposed by Hegde et al. (2015), for standard compressed sensing as well as for one-bit compressed sensing. We study both the noisy and noiseless regimes. Our analysis is general in the sense that it applies to any algorithm used to recover the signal. We carefully construct restricted ensembles for different settings and then apply Fano's inequality to establish the lower bound on the necessary number of samples. Furthermore, we show that our bound is tight for one-bit compressed sensing, while for standard compressed sensing, our bound is tight up to a logarithmic factor of the number of non-zero entries in the signal

Light Charged Higgs Bosons to AW/HW via Top Decay

While current ATLAS and CMS measurements exclude a light charged Higgs ($m_{H^\pm}<160$ GeV) for most of the parameter region in the context of the MSSM scenarios, these bounds are significantly weakened in the Type II 2HDM once the exotic decay channel into a lighter neutral Higgs, $H^\pm \to AW/HW$, is open. In this study, we examine the possibility of a light charged Higgs produced in top decay via single top or top pair production, with the subsequent decay $H^\pm \rightarrow AW/HW$, which can reach a sizable branching fraction at low $\tan\beta$ once it is kinematically permitted. With a detailed collider analysis, we obtain exclusion and discovery bounds for the 14 TeV LHC assuming the existence of a 70 GeV neutral scalar. Assuming ${\rm BR}(H^\pm \rightarrow AW/HW)=100\%$ and ${\rm BR}(A/H \rightarrow \tau\tau)=8.6\%$, the 95% exclusion limits on ${\rm BR}(t \rightarrow H^+ b)$ are about 0.2% and 0.03% for single top and top pair production respectively, with an integrated luminosity of 300 ${\rm fb}^{-1}$. The discovery reaches are about 3 times higher. In the context of the Type II 2HDM, discovery is possible at both large $\tan\beta > 17$ for 155 GeV $< m_{H^\pm} <$ 165 GeV, and small $\tan\beta < 6$ over the entire mass range. Exclusion is possible in the entire $\tan\beta$ versus $m_{H^\pm}$ plane except for charged Higgs masses close to the top threshold. The exotic decay channel $H^\pm \to AW/HW$ is therefore complementary to the conventional $H^\pm \rightarrow \tau\nu$ channel.Comment: 21 pages. arXiv admin note: text overlap with arXiv:1408.411

DISC1 is needed for the organization of cellular components at the immunological synapse.

T-cells carry out their immune functions through receptor-based recognition and adhesion to target cells. The cell-cell junction that is created from this connection is known as the immunological synapse (IS); a cellular structure composed of organized receptor clusters. Polymerization of F-actin at the synapse has been cited as a necessary step in the continuous activation and flow of T-cell receptors (TCR) towards the center of the synapse and activation of the integrin, Lymphocyte Function Associated Antigen 1 (LFA-1). These processes help T-cells form stable and specific connections with their cognate Antigen Presenting Cells (APCs). It has been previously shown that Disrupted in Schizophrenia 1 (DISC1), a protein with connections to actin-based signaling in neurons, is expressed in T-cells. Through immunofluorescence techniques and CRISPR-Cas9 knockout experiments, we have established that knocking out DISC1 inhibits the polymerization of actin filaments at the synapse. We also identified the actin-binding protein Girdin as a potential effector to actin-based functions of DISC1 at the synapse. We establish that Girdin is expressed at the immunological synapse and that Girdin knockout cell lines showed no detectable actin at the synapse, similar to DISC1 knockouts. Using immunoprecipitation techniques, we also show that DISC1 forms a complex with Girdin in Jurkat cells. Together, these experiments suggest that DISC1 plays a role in actin signaling at the synapse through interactions with Girdin.Molecular Bioscience

Excitation of multiple 2-mode parametric resonances by a single driven mode

We demonstrate autoparametric excitation of two distinct sub-harmonic mechanical modes by the same driven mechanical mode corresponding to different drive frequencies within its resonance dispersion band. This experimental observation is used to motivate a more general physical picture wherein multiple mechanical modes could be excited by the same driven primary mode within the same device as long as the frequency spacing between the sub-harmonic modes is less than half the dispersion bandwidth of the driven primary mode. The excitation of both modes is seen to be threshold-dependent and a parametric back-action is observed impacting on the response of the driven primary mode. Motivated by this experimental observation, modified dynamical equations specifying 2-mode auto-parametric excitation for such systems are presented.Comment: 8 pages, 3 figure

Report of Workshop on Mount Saint Helens: Its Atmospheric Effects and Potential Climatic Impact

The atmospheric and potential climatic aspects of a volcanic eruption were discussed. Measurements and techniques used in collecting the data are summarized