98,522 research outputs found
Weak Convergence of CD Kernels: A New Approach on the Circle and Real Line
Let m be a probability measure supported on some infinite and compact set K
in the complex plane and let p_n(z) be the corresponding degree n orthonormal
polynomial with positive leading coefficient. Let v_n be the normalized zero
counting measure for the polynomial p_n and let u_n be the probability measure
given by (n+1)u_n=K_n(z,z)m, where K_n(z,w) is the reproducing kernel for
polynomials of degree at most n. If m is supported on a compact subset of the
real line or the unit circle, we provide a new proof of a 2009 theorem due to
Simon, that for any fixed natural number k, the k^{th} moment of u_n and
v_{n+1} differ by at most O(1/n) as n tends to infinity.Comment: 6 pages; Version 2 includes minor changes to the exposition and
corrects minor typo
Intracellular free sodium and potassium, post-carbachol hyperpolarization, and extracellular potassium-undershoot in rat sympathetic neurones
Double-barrelled ion-sensitive microelectrodes were used to record the free intracellular Na+- and K+-concentrations ([Na+]i, [K+]i) and to determine their relation to changes in membrane potential and extracellular K+ ([K+]e) in rat sympathetic ganglia. The application of 50 μmol/l carbachol resulted in an elevation of [K+]e followed by a post-carbachol [K+]e-undershoot. The membrane depolarization of the sympathetic neurones was associated with an increase in [Na+]i and a decrease in [K+]i. A membrane hyperpolarization and a recovery of [K+]i and [Na+]i to their baseline levels were observed during the [K+]e-undershoot. The time course of the [K+]e-undershoot correlated exactly with the duration of the rise in [Na+]i and decrease of [K+]i. No K+-reuptake occurred in the presence of ouabain. These data confirm, by direct measurements of intracellular ion concentration changes, the contribution of the Na+, K+-pump to the post-carbachol membrane hyperpolarization and [K+]e-undershoot
Review of \u3cem\u3eThe End of Normal: The Great Crisis and the Future of Growth\u3c/em\u3e. James K. Galbraith. Reviewed by Charles Levenstein
James K. Galbraith, The End of Normal: The Great Crisis and the Future of Growth. Simon and Schuster (2014), 304 pages, 16.00 (paperback)
A version of Herbert A. Simon's model with slowly fading memory and its connections to branching processes
Construct recursively a long string of words w1. .. wn, such that at each
step k, w k+1 is a new word with a fixed probability p (0, 1), and
repeats some preceding word with complementary probability 1 -- p. More
precisely, given a repetition occurs, w k+1 repeats the j-th word with
probability proportional to j for j = 1,. .. , k. We show that the
proportion of distinct words occurring exactly times converges as the length n
of the string goes to infinity to some probability mass function in the
variable 1, whose tail decays as a power function when 1 -- p >
/(1 + ), and exponentially fast when 1 -- p < /(1 +
)
Search for high-mass dilepton resonances with the ATLAS experiment at sqrt(s) = 7 TeV
We present a search for high-mass l+l- resonances in pp collisions at a
centre-of-mass energy of 7 TeV recorded by the ATLAS experiment in 2011. No
statistically significant excess above the Standard Model expectation is
observed in a dataset corresponding to an integrated luminosity of
approximately 1/fb. Consequently, upper limits are set on the cross-section
times branching ratio of resonances decaying to muon pairs as a function of the
resonance mass. In particular, a Sequential Standard Model Z' is excluded for
masses below 1.83 TeV, and a Randall-Sundrum Kaluza-Klein graviton with
coupling k/M_Pl = 0.1 is excluded for masses below 1.63 TeV, both at the 95%
C.L.Comment: 3 pages, 3 figures, 2 tables, XXXI Physics In Collision Proceeding
The role of assumptions in causal discovery
The paper looks at the conditional independence search approach to causal discovery, proposed by Spirtes et al. and Pearl and Verma, from the point of view of the mechanism-based view of causality in econometrics, explicated by Simon. As demonstrated by Simon, the problem of determining the causal structure from data is severely underconstrained and the perceived causal structure depends on the a priori assumptions that one is willing to make. I discuss the assumptions made in the independence search-based causal discovery and their identifying strength
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