68 research outputs found
Frequentist Coverage Properties of Uncertainty Intervals for Weak Poisson Signals in the Presence of Background
We construct uncertainty intervals for weak Poisson signals in the presence
of background. We consider the case where a primary experiment yields a
realization of the signal plus background, and a second experiment yields a
realization of the background. The data acquisitions times for the
background-only experiment,T_bg, and the primary experiment,T, are selected so
that their ratio varies from 1 to 25. The expected number of background counts
in the primary experiment varies from 0.2 to 2. We construct 90 and 95 percent
confidence intervals based on a propagation-of-errors method as well as two
implementations of a Neyman procedure where acceptance regions are constructed
based on a likelihood-ratio criterion that automatically determines whether the
resulting confidence interval is one-sided or two-sided. The first Neyman
procedure (due to Feldman and Cousins) neglects uncertainty in the background.
In the other Neyman procedure, we account for uncertainty in the background
with a parametric bootstrap method. We also construct minimum length Bayesian
credibility intervals. For each method, we test for the presence of a signal
based on the value of the lower endpoint of the uncertainty interval. When
T_bg/T is 5 or more and the expected background is 2 or less, the Feldman
Cousins method outperforms the other methods considered.Comment: 12 pages,12 tables, 10 figures. This is the final version of a
manuscript that has been accepted for publication by Measurement Science and
Technolog
Electrical modalities beyond pacing for the treatment of heart failure
In this review, we report on electrical modalities, which do not fit the definition of pacemaker, but increase cardiac performance either by direct application to the heart (e.g., post-extrasystolic potentiation or non-excitatory stimulation) or indirectly through activation of the nervous system (e.g., vagal or sympathetic activation). The physiological background of the possible mechanisms of these electrical modalities and their potential application to treat heart failure are discussed
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