411 research outputs found
Cardinal characteristics at in a small u (κ) model
We provide a model where u(κ)<2κu(κ)<2κ for a supercompact cardinal κ. [10] provides a sketch of how to obtain such a model by modifying the construction in [6]. We provide here a complete proof using a different modification of [6] and further study the values of other natural generalizations of classical cardinal characteristics in our model. For this purpose we generalize some standard facts that hold in the countable case as well as some classical forcing notions and their properties
Long-term surveillance of SUDEP in drug-resistant epilepsy patients treated with VNS therapy.
Limited data are available regarding the evolution over time of the rate of sudden unexpected death in epilepsy patients (SUDEP) in drug-resistant epilepsy. The objective is to analyze a database of 40 443 patients with epilepsy implanted with vagus nerve stimulation (VNS) therapy in the United States (from 1988 to 2012) and assess whether SUDEP rates decrease during the postimplantation follow-up period.
Patient vital status was ascertained using the Centers for Disease Control and Prevention's National Death Index (NDI). An expert panel adjudicated classification of cause of deaths as SUDEP based on NDI data and available narrative descriptions of deaths. We tested the hypothesis that SUDEP rates decrease with time using the Mann-Kendall nonparametric trend test and by comparing SUDEP rates of the first 2 years of follow-up (years 1-2) to longer follow-up (years 3-10).
Our cohort included 277 661 person-years of follow-up and 3689 deaths, including 632 SUDEP. Primary analysis demonstrated a significant decrease in age-adjusted SUDEP rate during follow-up (S = -27 P = .008), with rates of 2.47/1000 for years 1-2 and 1.68/1000 for years 3-10 (rate ratio 0.68; 95% confidence interval [CI] 0.53-0.87; P = .002). Sensitivity analyses confirm these findings.
Our data suggest that SUDEP risk significantly decreases during long-term follow-up of patients with refractory epilepsy receiving VNS Therapy. This finding might reflect several factors, including the natural long-term dynamic of SUDEP rate, attrition, and the impact of VNS Therapy. The role of each of these factors cannot be confirmed due to the limitations of the study
Is there a Jordan geometry underlying quantum physics?
There have been several propositions for a geometric and essentially
non-linear formulation of quantum mechanics. From a purely mathematical point
of view, the point of view of Jordan algebra theory might give new strength to
such approaches: there is a ``Jordan geometry'' belonging to the Jordan part of
the algebra of observables, in the same way as Lie groups belong to the Lie
part. Both the Lie geometry and the Jordan geometry are well-adapted to
describe certain features of quantum theory. We concentrate here on the
mathematical description of the Jordan geometry and raise some questions
concerning possible relations with foundational issues of quantum theory.Comment: 30 page
An Energy- and Charge-conserving, Implicit, Electrostatic Particle-in-Cell Algorithm
This paper discusses a novel fully implicit formulation for a 1D
electrostatic particle-in-cell (PIC) plasma simulation approach. Unlike earlier
implicit electrostatic PIC approaches (which are based on a linearized
Vlasov-Poisson formulation), ours is based on a nonlinearly converged
Vlasov-Amp\`ere (VA) model. By iterating particles and fields to a tight
nonlinear convergence tolerance, the approach features superior stability and
accuracy properties, avoiding most of the accuracy pitfalls in earlier implicit
PIC implementations. In particular, the formulation is stable against temporal
(CFL) and spatial (aliasing) instabilities. It is charge- and energy-conserving
to numerical roundoff for arbitrary implicit time steps. While momentum is not
exactly conserved, errors are kept small by an adaptive particle sub-stepping
orbit integrator, which is instrumental to prevent particle tunneling. The VA
model is orbit-averaged along particle orbits to enforce an energy conservation
theorem with particle sub-stepping. As a result, very large time steps,
constrained only by the dynamical time scale of interest, are possible without
accuracy loss. Algorithmically, the approach features a Jacobian-free
Newton-Krylov solver. A main development in this study is the nonlinear
elimination of the new-time particle variables (positions and velocities). Such
nonlinear elimination, which we term particle enslavement, results in a
nonlinear formulation with memory requirements comparable to those of a fluid
computation, and affords us substantial freedom in regards to the particle
orbit integrator. Numerical examples are presented that demonstrate the
advertised properties of the scheme. In particular, long-time ion acoustic wave
simulations show that numerical accuracy does not degrade even with very large
implicit time steps, and that significant CPU gains are possible.Comment: 29 pages, 8 figures, submitted to Journal of Computational Physic
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Untangling a Web of Lies: Exploring Automated Detection of Deception in Computer-Mediated Communication
Safeguarding organizations against opportunism and severe deception in computer-mediated communication (CMC) presents a major challenge to CIOs and IT managers. New insights into linguistic cues of deception derive from the speech acts innate to CMC. Applying automated text analysis to archival email exchanges in a CMC system as part of a reward program, we assess the ability of word use (micro-level), message development (macro-level), and intertextual exchange cues (meta-level) to detect severe deception by business partners. We empirically assess the predictive ability of our framework using an ordinal multilevel regression model. Results indicate that deceivers minimize the use of referencing and self-deprecation but include more superfluous descriptions and flattery. Deceitful channel partners also over structure their arguments and rapidly mimic the linguistic style of the account manager across dyadic e-mail exchanges. Thanks to its diagnostic value, the proposed framework can support firms’ decision-making and guide compliance monitoring system development
On the uniqueness of smooth, stationary black holes in vacuum
We prove a conditional "no hair" theorem for smooth manifolds: if is the
domain of outer communication of a smooth, regular, stationary Einstein vacuum,
and if a technical condition relating the Ernst potential and Killing scalar is
satisfied on the bifurcate sphere, then is locally isometric to the domain
of outer communication of a Kerr space-time.Comment: Various correction
Hypogene Calcitization: Evaporite Diagenesis in the Western Delaware Basin
Evaporite calcitization within the Castile Formation of the Delaware Basin is more widespread and diverse than originally recognized. Coupled field and GIS studies have identified more than 1000 individual occurrences of calcitization within the Castile Formation outcrop area, which includes both calcitized masses (limestone buttes) and laterally extensive calcitized horizons (limestone sheets). Both limestone buttes and sheets commonly contain a central brecciated zone that we attribute to hypogene dissolution. Lithologic fabric of calcitized zones ranges from little alteration of original varved laminae to fabrics showing extensive laminae distortion as well as extensive vuggy and open cavernous porosity. Calcitization is most abundant in the western portion of the Castile outcrop region where surface denudation has been greatest. Calcitization often forms linear trends, indicating fluid migration along fractures, but also occurs as dense clusters indicating focused, ascending, hydrocarbon-rich fluids. Native sulfur, secondary tabular gypsum (i.e. selenite) and hypogene caves are commonly associated with clusters of calcitization. This assemblage suggests that calcium sulfate diagenesis within the Castile Formation is dominated by hypogene speleogemesis
Sickonomics : Diagnoses and remedies
Original article can be found at: http://www.tandfonline.com/ Copyright Taylor & FrancisIn their recent analysis of the alleged decay in modern economics, Ben Fine and Dimitris Milonakis claim to find its source and origin in the "marginal revolution" of the 1870s. They argue that this development led to "methodological individualism" and the detachment of economics from society and history. I contest their account of the marginal revolution and of the role of Alfred Marshall among others. They also fail to provide an adequate definition of methodological individualism. I suggest that neoclassical economics adopted a denuded concept of the social rather than removing these factors entirely. No such removal is possible in principle. It is also mistaken to depict neoclassical economics as the science of prices and the market. In truth, neoclassical economics fails to capture the true nature of markets. I consider some sketch an alternative explanation of the sickness of modern economics, which focuses on institutional developments since World War II.Peer reviewe
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