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A joint regression modeling framework for analyzing bivariate binary data in R
We discuss some of the features of the R add-on package GJRM which implements a flexible joint modeling framework for fitting a number of multivariate response regression models under various sampling schemes. In particular,we focus on the case inwhich the user wishes to fit bivariate binary regression models in the presence of several forms of selection bias. The framework allows for Gaussian and non-Gaussian dependencies through the use of copulae, and for the association and mean parameters to depend on flexible functions of covariates. We describe some of the methodological details underpinning the bivariate binary models implemented in the package and illustrate them by fitting interpretable models of different complexity on three data-sets
Binary Fluids with Long Range Segregating Interaction I: Derivation of Kinetic and Hydrodynamic Equations
We study the evolution of a two component fluid consisting of ``blue'' and
``red'' particles which interact via strong short range (hard core) and weak
long range pair potentials. At low temperatures the equilibrium state of the
system is one in which there are two coexisting phases. Under suitable choices
of space-time scalings and system parameters we first obtain (formally) a
mesoscopic kinetic Vlasov-Boltzmann equation for the one particle position and
velocity distribution functions, appropriate for a description of the phase
segregation kinetics in this system. Further scalings then yield Vlasov-Euler
and incompressible Vlasov-Navier-Stokes equations. We also obtain, via the
usual truncation of the Chapman-Enskog expansion, compressible
Vlasov-Navier-Stokes equations.Comment: TeX, 50 page
Kinetics of a Model Weakly Ionized Plasma in the Presence of Multiple Equilibria
We study, globaly in time, the velocity distribution of a spatially
homogeneous system that models a system of electrons in a weakly ionized
plasma, subjected to a constant external electric field . The density
satisfies a Boltzmann type kinetic equation containing a full nonlinear
electron-electron collision term as well as linear terms representing
collisions with reservoir particles having a specified Maxwellian distribution.
We show that when the constant in front of the nonlinear collision kernel,
thought of as a scaling parameter, is sufficiently strong, then the
distance between and a certain time dependent Maxwellian stays small
uniformly in . Moreover, the mean and variance of this time dependent
Maxwellian satisfy a coupled set of nonlinear ODE's that constitute the
``hydrodynamical'' equations for this kinetic system. This remain true even
when these ODE's have non-unique equilibria, thus proving the existence of
multiple stabe stationary solutions for the full kinetic model. Our approach
relies on scale independent estimates for the kinetic equation, and entropy
production estimates. The novel aspects of this approach may be useful in other
problems concerning the relation between the kinetic and hydrodynamic scales
globably in time.Comment: 30 pages, in TeX, to appear in Archive for Rational Mechanics and
Analysis: author's email addresses: [email protected],
[email protected], [email protected],
[email protected], [email protected]
Assessing the volcanic hazard for Rome. 40Ar/39Ar and In-SAR constraints on the most recent eruptive activity and present-day uplift at Colli Albani Volcanic District
We present new 40Ar/39Ar data which allow us to refine the recurrence time for the most recent eruptive activity occurred at Colli Albani Volcanic District (CAVD) and constrain its geographic area. Time elapsed since the last eruption (36 kyr) overruns the recurrence time (31 kyr) in the last 100 kyr. New interferometric synthetic aperture radar data, covering the years 1993–2010, reveal ongoing inflation with maximum uplift rates (>2 mm/yr) in the area hosting the most recent (<200 ka) vents, suggesting that the observed uplift might be caused by magma injection within the youngest plumbing system. Finally, we frame the present deformation within the structural pattern of the area of Rome, characterized by 50 m of regional uplift since 200 ka and by geologic evidence for a recent (<2000 years) switch of the local stress-field, highlighting that the precursors of a new phase of volcanic activity are likely occurring at the CAVD
Propagation of Chaos for a Thermostated Kinetic Model
We consider a system of N point particles moving on a d-dimensional torus.
Each particle is subject to a uniform field E and random speed conserving
collisions. This model is a variant of the Drude-Lorentz model of electrical
conduction. In order to avoid heating by the external field, the particles also
interact with a Gaussian thermostat which keeps the total kinetic energy of the
system constant. The thermostat induces a mean-field type of interaction
between the particles. Here we prove that, starting from a product measure, in
the large N limit, the one particle velocity distribution satisfies a self
consistent Vlasov-Boltzmann equation.. This is a consequence of "propagation of
chaos", which we also prove for this model.Comment: This version adds affiliation and grant information; otherwise it is
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Phase noise characterization of injection locked semiconductor lasers to a 250 MHz optical frequency comb
Two lasers are simultaneously injection locked to the same comb mode and the injection locking quality is assessed in terms of phase noise and phase variance (1 kHz-10 MHz) for various injected powers
5 Tips for a Successful Parent and Teacher Relationship
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http://inallthings.org/5-tips-for-a-successful-parent-and-teacher-relationship
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