A Threshold Model of Real US GDP and the Problem of Constructing Confidence Intervals in TAR Models

We estimate real U.S. GDP growth as a threshold autoregressive process, and construct confidence intervals for the parameter estimates. However, there are various approaches that can be used in constructing the confidence intervals. Specifically, standard- t , bootstrap- t , and bootstrap-percentile confidence intervals are simulated for the slope coefficients and the estimated threshold. However, the results for the different methods have very different economic implications. We perform a Monte Carlo experiment to evaluate the various methods.Bootstrap GDP; Threshold Autoregression; Bootstrap Confidence Intervals

Resonant tunneling of electromagnetic waves through polariton gaps

We consider resonant tunneling of electromagnetic waves through an optical barrier formed by dielectric layers with the frequency dispersion of their dielectric permiability. The frequency region between lower and upper polariton branches in these materials presents a stop band for electromagnetic waves. We show that resonance tunneling through this kind of barriers is qualitatevely different from tunneling through other kind of optical barriers as well as from quantum mechanic tunneling through a rectangular barrier. We find that the width of the resonance maxima of the transmission coeffcient tends to zero as frequency approach the lower boundary of the stop band in a very sharp non-analytical way. Resonance transmission peaks give rise to new photonic bands inside the stop band if one considers periodical array of the layers.Comment: 8 pages, 5 figure

Lorentz Invariant Superluminal Tunneling

It is shown that superluminal optical signalling is possible without violating Lorentz invariance and causality via tunneling through photonic band gaps in inhomogeneous dielectrics of a special kind.Comment: 10 pages revtex, no figure, more discussions added, submitted to Phys. Rev.

Single Proton Knock-Out Reactions from 24,25,26F

The cross sections of the single proton knock-out reactions from 24F, 25F, and 26F on a 12C target were measured at energies of about 50 MeV/nucleon. Ground state populations of 6.6+-.9 mb, 3.8+-0.6 mb for the reactions 12C(24F,23O) and 12C(25F,24O) were extracted, respectively. The data were compared to calculations based on the many-body shell model and the eikonal theory. In the reaction 12C(26F,25O) the particle instability of 25O was confirmed

Hydrogen-induced ferromagnetism in two-dimensional Pt dichalcogenides

Electronic, structural, and magnetic properties of Pt dichalcogenide monolayers are investigated using firstprinciple calculations.We find that hydrogenation lifts the spin degeneracy in narrow antibonding Pt 5d subband electrons and transforms the nonmagnetic semiconductors PtX2 (X = S,Se,Te) into ferromagnetic metals, PtX2-1H; neither strain nor thin-film edges are necessary to support the transition. The trend towards ferromagnetism is most pronounced for X = S, decreasing with increasing atomic weight of the chalcogens

A laboratory study of caching in Desmodillus auricularis

No Abstrac

Influence of Temperature and Concentration on the Self-Assembly of Nonionic CiEjSurfactants: A Light Scattering Study

Nonionic poly(ethylene oxide) alkyl ether (C$_{i}$iE$_{j}$) surfactants self-assemble into aggregates of various sizes and shapes above their critical micelle concentration (CMC). Knowledge on solution attributes such as CMC as well as aggregate characteristics is crucial to choose the appropriate surfactant for a given application, e.g., as a micellar solvent system. In this work, we used static and dynamic light scattering to measure the CMC, aggregation number (N$_{agg}$), and hydrodynamic radius (R$_{h}$) of four different C$_{i}$E$_{j}$ surfactants (C$_{8}$E$_{5}$, C$_{8}$E$_{6}$, C$_{10}$E$_{6}$, and C$_{10}$E$_{8}$). We examined the influence of temperature, concentration, and molecular structure on the self-assembly in the vicinity of the CMC. A minimum in the CMC vs temperature curve was identified for all surfactants investigated. Further, extending the hydrophilic and hydrophobic chain lengths leads to an increase and decrease of the CMC, respectively. The size of the aggregates strongly depends on temperature. N$_{agg}$ and R$_{h}$ increase with increasing temperature for all surfactants investigated. Additionally, N$_{agg}$ and R$_{h}$ both increase with increasing surfactant concentration. The data obtained in this work further improve the understanding of the influence of temperature and molecular structure on the self-assembly of C$_{i}$iE$_{j}$ surfactants and will further foster their use in micellar solvent systems