Noise sustained propagation: Local versus global noise

We expand on prior results on noise supported signal propagation in arrays of coupled bistable elements. We present and compare experimental and numerical results for kink propagation under the influence of local and global fluctuations. As demonstrated previously for local noise, an optimum range of global noise power exists for which the medium acts as a reliable transmission ``channel''. We discuss implications for propagation failure in a model of cardiac tissue and present a general theoretical framework based on discrete kink statistics. Valid for generic bistable chains, the theory captures the essential features ob served in our experiments and numerical simulations.Comment: 1 latex file 20 pages, 9 figures. Accepted for publication in Physical Review

Branching Ratio and CP Asymmetry of B_s \to K^*_0(1430)\pi Decays in the PQCD Approach

In the two-quark model supposition for $K_0^{*}(1430)$, the branching ratios and the direct CP-violating asymmetries for decays $\bar B_s^0\to K^{*0}_0(1430)\pi^0, K^{*+}_0(1430)\pi^-$ are studied by employing the perturbative QCD factorization approach. We find that although these two decays are both tree-dominated, the ratio of their penguin to tree contributions are very different: there is only a few percent for the decay $\bar B_s^0\to K^{*+}_0(1430)\pi^-$, while about 37% in scenario I, even 51% in scenario II for the decay $\bar B_s^0\to K^{*0}_0(1430)\pi^0$. It results that these two decays have very different values in the branching ratios and the direct CP asymmetries. The branching ratio of the decay $\bar B_s^0\to K^{*+}_0(1430)\pi^-$ is at the order of $10^{-5}$, and its direct CP asymmetry is about (20-30)%. While for the decay $\bar B_s^0\to K^{*0}_0(1430)\pi^0$, its direct CP-violating asymmetry is very large and about 90%, but it is difficult to measure it, because the branching ratio for this channel is small and only $10^{-7}$ order.Comment: 8pages, 2figure

New study of the isotensor pi-pi interaction

With t-channel rho, f2(1270) exchange and the pi pi -> rho rho -> pi pi box diagram contribution, we reproduce the pi pi isotensor S-wave and D-wave scattering phase shifts and inelasticities up to 2.2 GeV quite well in a K-matrix formalism. The t-channel rho exchange provides repulsive negative phase shifts while the t-channel f2(1270) gives an attractive force to increase the phase shifts for pi pi scattering above 1 GeV, and the coupled-channel box diagram causes the inelasticities. The implication to the isoscalar pi pi S-wave interaction is discussed.Comment: 17 pages, 5 figure

Lessons Learned: Recruiting Aging Adults for Research

Aging adults are the fastest-growing population in the United States, but they are underrepresented in health care research. Evidence-based decisions for aging adults need to be made using research done with this population. However, recruiting aging adults into research has many challenges. This article presents multiple cases of recruiting aging adults into nutrition research studies in 3 different US geographic locations. The challenges, successes, and lessons learned are presented. The lessons learned can provide guidance to others already doing research with aging adults and those clinical and community dietitians who want to start doing research with aging adults

Systematic Theoretical Search for Dibaryons in a Relativistic Model

A relativistic quark potential model is used to do a systematic search for quasi-stable dibaryon states in the $u$, $d$, and $s$ three flavor world. Flavor symmetry breaking and channel coupling effects are included and an adiabatic method and fractional parentage expansion technique are used in the calculations. The relativistic model predicts dibaryon candidates completely consistent with the nonrelativistic model.Comment: 12 pages, latex, no figure

Energy-dependent photoemission delays from noble metal surfaces by attosecond interferometry

How quanta of energy and charge are transported on both atomic spatial and ultrafast time scales is at the heart of modern technology. Recent progress in ultrafast spectroscopy has allowed us to directly study the dynamical response of an electronic system to interaction with an electromagnetic field. Here, we present energy-dependent photoemission delays from the noble metal surfaces Ag(111) and Au(111). An interferometric technique based on attosecond pulse trains is applied simultaneously in a gas phase and a solid state target to derive surface-specific photoemission delays. Experimental delays on the order of 100 as are in the same time range as those obtained from simulations. The strong variation of measured delays with excitation energy in Ag(111), which cannot be consistently explained invoking solely electron transport or initial state localization as supposed in previous work, indicates that final state effects play a key role in photoemission from solids

Mutations in the C-terminal region of the HIV-1 reverse transcriptase and their correlation with drug resistance associated mutations and antiviral treatment

<p>Abstract</p> <p>Objective</p> <p>Replication of HIV-1 after cell entry is essentially dependent on the reverse transcriptase (RT). Antiretroviral drugs impairing the function of the RT currently aim at the polymerase subunit. One reason for failure of antiretroviral treatment is the evolvement of resistance-associated mutations in the viral genome. For RT inhibitors, almost all identified mutations are located within the polymerase; therefore, general genotyping confines to investigate this subunit. Recently several studies have shown that substitutions within the RNase H and the connection domain increase antiviral drug-resistance in vitro, and some of them are present in patient isolates.</p> <p>Aim</p> <p>The aim of the present study was to investigate the prevalence of these substitutions and their association with mutations in the polymerase domain arising during antiretroviral treatment.</p> <p>Materials and methods</p> <p>We performed genotypic analyzes on seventy-four virus isolates derived from treated and untreated patients, followed at the HIV Centre of the Johann Wolfgang Goethe University Hospital (Frankfurt/Main, Germany). We subsequently analysed the different substitutions in the c-terminal region to evaluate whether there were associations with each other, n-terminal substitutions or with antiretroviral treatment.</p> <p>Results</p> <p>We identified several primer grip substitutions, but almost all of them were located in the connection domain. This is consistent with other in-vivo studies, in which especially the primer grip residues located in the RNase H were unvaried. Furthermore, we identified other substitutions in the connection domain and in the RNase H. Especially E399D seemed to be associated with an antiretroviral treatment and N-terminal resistance-delivering mutations.</p> <p>Conclusion</p> <p>Some of the identified substitutions were associated with antiviral treatment and drug resistance-associated mutations. Due to the low prevalence of C-terminal mutations and as only a few of them could be associated with antiviral treatment and N-terminal resistance-delivering mutations, we would not recommend routinely testing of the C-terminal RT region.</p

Three channel model of meson-meson scattering and scalar meson spectroscopy

New solutions on the scalar -- isoscalar $\pi\pi$ phase shifts are analysed together with previous $K\bar{K}$ results using a separable potential model of three coupled channels ($\pi\pi$, $K\bar{K}$ and an effective $2\pi 2\pi$ system). Model parameters are fitted to two sets of solutions obtained in a recent analysis of the CERN-Cracow-Munich measurements of the $\pi^- p_{\uparrow} \to \pi^+ \pi^- n$ reaction on a polarized target. A relatively narrow (90 -- 180 MeV) scalar resonance $f_0(1400-1460)$ is found, in contrast to a much broader ($\Gamma \approx 500$ MeV) state emerging from the analysis of previous unpolarized target data.Comment: 10 Latex pages + 6 postscript figure

Spatial stochastic resonance in 1D Ising systems

The 1D Ising model is analytically studied in a spatially periodic and oscillatory external magnetic field using the transfer-matrix method. For low enough magnetic field intensities the correlation between the external magnetic field and the response in magnetization presents a maximum for a given temperature. The phenomenon can be interpreted as a resonance phenomenon induced by the stochastic heatbath. This novel "spatial stochastic resonance" has a different origin from the classical stochastic resonance phenomenon.Comment: REVTex, 5 pages, 3 figure

Linguistic expert creation in online health practices

In this chapter, we explore how the construction of an expert identity varies across online e-health settings with different socio-technological features. Our methodology is qualitative in nature and draws on insights from discourse analysis, in particular positioning theory. Results show that four aspects of creating expertise are vital: the embeddedness of the posi-tioning strategies in the online health context, the interplay between these strategies within each setting, the interactivity of the medium, and the fact that not only professionals, but also clients and laypeople construct their expertise. The results reveal that previously found strategies to create expertise (e.g., using jargon or showing empathy) could be confirmed in our corpus, and that the interplay of several strategies is in fact needed to create credible and trustworthy expert identities for all participants involved. This interplay varies accord-ing to the practice