On the pion-nucleon coupling constant

In view of persisting misunderstanding about the determination of the pion-nucleon coupling constants in the Nijmegen multienergy partial-wave analyses of pp, np, and pbar-p scattering data, we present additional information which may clarify several points of discussion. We comment on several recent papers addressing the issue of the pion-nucleon coupling constant and criticizing the Nijmegen analyses.Comment: 19 pages, Nijmegen preprint THEF-NYM-92-0

Observation of the Higgs Boson of strong interaction via Compton scattering by the nucleon

It is shown that the Quark-Level Linear $\sigma$ Model (QLL$\sigma$M) leads to a prediction for the diamagnetic term of the polarizabilities of the nucleon which is in excellent agreement with the experimental data. The bare mass of the $\sigma$ meson is predicted to be $m_\sigma=666$ MeV and the two-photon width $\Gamma(\sigma\to\gamma\gamma)=(2.6\pm 0.3)$ keV. It is argued that the mass predicted by the QLL$\sigma$M corresponds to the $\gamma\gamma\to\sigma\to NN$ reaction, i.e. to a $t$-channel pole of the $\gamma N\to N\gamma$ reaction. Large -angle Compton scattering experiments revealing effects of the $\sigma$ meson in the differential cross section are discussed. Arguments are presented that these findings may be understood as an observation of the Higgs boson of strong interaction while being part of the constituent quark.Comment: 17 pages, 6 figure

Josephson Coupling and Fiske Dynamics in Ferromagnetic Tunnel Junctions

We report on the fabrication of Nb/AlO_x/Pd_{0.82}Ni_{0.18}/Nb superconductor/insulator/ferromagnetic metal/superconductor (SIFS) Josephson junctions with high critical current densities, large normal resistance times area products, high quality factors, and very good spatial uniformity. For these junctions a transition from 0- to \pi-coupling is observed for a thickness d_F ~ 6 nm of the ferromagnetic Pd_{0.82}Ni_{0.18} interlayer. The magnetic field dependence of the \pi-coupled junctions demonstrates good spatial homogeneity of the tunneling barrier and ferromagnetic interlayer. Magnetic characterization shows that the Pd_{0.82}Ni_{0.18} has an out-of-plane anisotropy and large saturation magnetization, indicating negligible dead layers at the interfaces. A careful analysis of Fiske modes provides information on the junction quality factor and the relevant damping mechanisms up to about 400 GHz. Whereas losses due to quasiparticle tunneling dominate at low frequencies, the damping is dominated by the finite surface resistance of the junction electrodes at high frequencies. High quality factors of up to 30 around 200 GHz have been achieved. Our analysis shows that the fabricated junctions are promising for applications in superconducting quantum circuits or quantum tunneling experiments.Comment: 15 pages, 9 figure

Chronic anticoagulation with warfarin is associated with decreased functional outcome and increased length of stay following craniotomy for acute subdural hematoma

Introduction: With the continued rise of the aging population, the incidence of acute subdural hematoma (ASDH) in the setting of chronic oral anticoagulation with warfarin is expected to increase. No study has directly addressed the risks of poorer outcomes in chronically anticoagulated patients after ASDH evacuation. Methods: We reviewed retrospectively 94 consecutive cases of ASDH at a single institution with fresh frozen plasma and craniotomy. The outcomes of patients with ASDH in the setting of chronic oral anticoagulation were compared to those of patients with ASDH not taking oral anticoagulation. Results: There were 22 patients receiving chronic anticoagulation (11 male, 11 female, mean age 63.7 ± 4 years) with ASDH requiring craniotomy for evacuation. These patients had significantly lower mean discharge Glasgow Outcome Scores (GOS) when compared to control subjects (2.3 ± 0.3 versus 3.0 ± 0.2). Despite presentation with higher Glasgow Coma Scores (GCS), ASDH size tended to be larger in anticoagulated patients, although not significant. Overall mortality was nearly double, that is 55% in anticoagulated patients compared to 29% in those without anticoagulation. Of previously anticoagulated patients alive at discharge, hospital length of stay was longer compared to controls (31.9 ± 8.5 days versus 21.1 ± 2.4 days). Conclusions: These data suggest that ASDH evacuation in chronically anticoagulated patients is associated with higher mortality rates, decreased likelihood of independent function, and increased length of hospital stay. Further research is needed to determine if the effect of chronic anticoagulation on outcome is independent of cofounders, such as age and medical comorbidities. These data may help practitioners and families create treatment plans and furthermore serve as the gold standard for the future evaluation of novel anticoagulation reversal agents such as factor VIIa

Upstream stimulating factors: highly versatile stress-responsive transcription factors

International audienceUpstream stimulating factors (USF), USF-1 and USF-2, are members of the eucaryotic evolutionary conserved basic-Helix-Loop-Helix-Leucine Zipper transcription factor family. They interact with high affinity to cognate E-box regulatory elements (CANNTG), which are largely represented across the whole genome in eucaryotes. The ubiquitously expressed USF-transcription factors participate in distinct transcriptional processes, mediating recruitment of chromatin remodelling enzymes and interacting with co-activators and members of the transcription pre-initiation complex. Results obtained from both cell lines and knock-out mice indicates that USF factors are key regulators of a wide number of gene regulation networks, including the stress and immune responses, cell cycle and proliferation, lipid and glucid metabolism, and in melanocytes USF-1 has been implicated as a key UV-activated regulator of genes associated with pigmentation. This review will focus on general characteristics of the USF-transcription factors and their place in some regulatory networks