8,778 research outputs found
Motor units distribution and recruitment order retrieved from force / M-wave relationship during stimulated contraction
Symmetry breaking: A tool to unveil the topology of chaotic scattering with three degrees of freedom
We shall use symmetry breaking as a tool to attack the problem of identifying
the topology of chaotic scatteruing with more then two degrees of freedom.
specifically we discuss the structure of the homoclinic/heteroclinic tangle and
the connection between the chaotic invariant set, the scattering functions and
the singularities in the cross section for a class of scattering systems with
one open and two closed degrees of freedom.Comment: 13 pages and 8 figure
Study of thermal protection requirements for a lifting body entry vehicle suitable for near-earth missions Final report
Reentry and abort trajectory analyses, and thermal protection requirements for lifting body entry vehicle
CP violation with a dynamical Higgs
We determine the complete set of independent gauge and gauge-Higgs CP-odd
effective operators for the generic case of a dynamical Higgs, up to four
derivatives in the chiral expansion. The relation with the linear basis of
dimension six CP-odd operators is clarified. Phenomenological applications
include bounds inferred from electric dipole moment limits, and from present
and future collider data on triple gauge coupling measurements and Higgs
signals.Comment: 41 pages, 3 figures; V2: citations added, typos corrected, version
published on JHE
Multilevel versus Single-Level Regression for the Analysis of Multilevel Information:The Case of Quantitative Intersectional Analysis
Intersectional MAIHDA involves applying multilevel models in order to estimate intercategorical inequalities. The approach has been validated thus far using both simulations and empirical applications, and has numerous methodological and theoretical advantages over single-level approaches, including parsimony and reliability for analyzing high-dimensional interactions. In this issue of SSM, Lizotte, Mahendran, Churchill and Bauer (hereafter âLMCBâ) assert that there has been insufficient clarity on the interpretation of fixed effects regression coefficients in intersectional MAIHDA, and that stratum-level residuals in intersectional MAIHDA are not interpretable as interaction effects. We disagree with their second assertion; however, the authors are right to call for greater clarity. For this purpose, in this response we have three main objectives. (1) In their commentary, LMCB incorrectly describe model predictions based on MAIHDA fixed effects as estimates of âgrand meansâ (or the mean of means), when they are actually âprecision-weighted grand means.â We clarify the differences between average predicted values obtained by different models, and argue that predictions obtained by MAIHDA are more suitable to serve as reference points for residual/interaction effects. This further enables us to clarify the interpretation of residual/interaction effects in MAIHDA and conventional models. Using simple simulations, we demonstrate conditions under which the precision-weighted grand mean resembles a grand mean, and when it resembles a population mean (or the mean of all individual observations) obtained using single-level regression, explaining the results obtained by LMCB and informing future research. (2) We construct a modification to MAIHDA that constrains the fixed effects so that the resulting model predictions provide estimates of population means, which we use to demonstrate the robustness of results reported by Evans et al. (2018). We find that stratum-specific residuals obtained using the two approaches are highly correlated (Pearson corr = 0.98, p < 0.0001) and no substantive conclusions would have been affected if the preference had been for estimating population means. However, we advise researchers to use the original, unconstrained MAIHDA. (3) Finally, we outline the extent to which single-level and MAIHDA approaches address the fundamental goals of quantitative intersectional analyses and conclude that intersectional MAIHDA remains a promising new approach for the examination of inequalities
Higgs ultraviolet softening
We analyze the leading effective operators which induce a quartic momentum
dependence in the Higgs propagator, for a linear and for a non-linear
realization of electroweak symmetry breaking. Their specific study is relevant
for the understanding of the ultraviolet sensitivity to new physics. Two
methods of analysis are applied, trading the Lagrangian coupling by: i) a
"ghost" scalar, after the Lee-Wick procedure; ii) other effective operators via
the equations of motion. The two paths are shown to lead to the same effective
Lagrangian at first order in the operator coefficients. It follows a
modification of the Higgs potential and of the fermionic couplings in the
linear realization, while in the non-linear one anomalous quartic gauge
couplings, Higgs-gauge couplings and gauge-fermion interactions are induced in
addition. Finally, all LHC Higgs and other data presently available are used to
constrain the operator coefficients; the future impact of data via off-shell Higgs exchange and of vector boson fusion data is
considered as well. For completeness, a summary of pure-gauge and gauge-Higgs
signals exclusive to non-linear dynamics at leading-order is included.Comment: 31 pages, 3 figures, 7 table
Integrating Superconductive and Optical Circuits
We have integrated on oxidized silicon wafers superconductive films and
Josephson junctions along with sol-gel optical channel waveguides. The
fabrication process is carried out in two steps that result to be solid and
non-invasive. It is demonstrated that 660 nm light, coupled from an optical
fibre into the channel sol-gel waveguide, can be directed toward
superconducting tunnel junctions whose current-voltage characteristics are
affected by the presence of the radiation. The dependence of the change in the
superconducting energy gap under optical pumping is discussed in terms of a
non-equilibrium superconductivity model.Comment: Document composed of 7 pages of text and 3 figure
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