Breaks, bubbles, booms, and busts: the evolution of primary commodity price fundamentals

This paper explores the behavior of real commodity prices over a 50–year period. Attention is given to how the fundamentals for various commodity prices have changed with a special emphasis on behavior since the mid 2000s. To identify changing commodity price fundamentals we estimate shifting–mean autoregressions by using: the Bai and Perron (1998) procedure for estimating structural breaks; a SlowShift procedure that specifies intercepts to be nonlinear, potentially smooth functions of time; and low frequency Fourier functions. We find that the pattern in the timing of the various shifts is suggestive of the causal fundamentals underlying the recent boom.Commodity Prices, Fundamentals, Nonlinear Trends, Shifting--Mean Autoregression

Authoritarian populist Americans who feel a sense of victimhood and white identity are most likely to support political violence

The capitol insurrection of January 6, 2021 brought the rise of political violence in America into sharp focus. But who supports the use of violence to achieve their political goals? In new survey research, Miles T. Armaly and Adam M. Enders find that feelings of victimhood, authoritarian and populist sentiments and white identity have the strongest link to support for political violence. They also find that support for political violence is not closely linked to support for a political party, nor is it widespread, with only 13 percent of respondents supporting it

On "the authentic damping mechanism" of the phonon damping model

Some general features of the phonon damping model are presented. It is concluded that the fits performed within this model have no physical content

Hyperfine Structure Constants for Eu Isotopes: Is The Empirical Formula of HFS Anomaly Universal ?

We calculate the hyperfine structure constant for the Eu isotopes with shell model wave functions. The calculated results are compared with those predicted by the Moskowitz-Lombardi (M-L) empirical formula. It turns out that the two approaches give the very different behaviors of the hfs constants in the isotope dependence. This should be easily measured by experiment, which may lead to the universality check of the M-L formula.Comment: 18 pages, Latex, two figure

g-factor of a tightly bound electron

We study the hyperfine splitting of an electron in hydrogen-like $^{209}Bi ^{82+}$. It is found that the hfs energy splitting can be explained well by considering the g-factor reduction due to the binding effect of a bound electron. We determine for the first time the experimental value of the magnetic moment of a tightly bound electron.Comment: 6 pages, Latex, Phys. Rev. A in pres

Apparent Superluminal Behavior

The apparent superluminal propagation of electromagnetic signals seen in recent experiments is shown to be the result of simple and robust properties of relativistic field equations. Although the wave front of a signal passing through a classically forbidden region can never move faster than light, an attenuated replica of the signal is reproduced ``instantaneously'' on the other side of the barrier. The reconstructed signal, causally connected to the forerunner rather than the bulk of the input signal, appears to move through the barrier faster than light.Comment: 8 pages, no figure

Design rules for active control of narrowband thermal emission using phase-change materials

We propose an analytical framework to design actively tunable narrowband thermal emitters at infrared frequencies. We exemplify the proposed design rules using phase-change materials (PCM), considering dielectric-to-dielectric PCMs (e.g. GSST) and dielectric-to-metal PCMs (e.g. $\mathrm{VO_2}$). Based on these, we numerically illustrate near-unity ON-OFF switching and arbitrarily large spectral shifting between two emission wavelengths, respectively. The proposed systems are lithography-free and consist of one or several thin emitter layers, a spacer layer which includes the PCM, and a back reflector. Our model applies to normal incidence, though we show that the behavior is essentially angle-independent. The presented formalism is general and can be extended to \textit{any} mechanism that modifies the optical properties of a material, such as electrostatic gating or thermo-optical modulation.Comment: 9 pages, 6 figure

Hyperfine Anomaly of Be Isotopes and Anomalous Large Anomaly in 11^{11}Be

A new result of investigations of the hyperfine structure (hfs) anomaly in Be isotopes is presented. The hfs constant for $^{11}$Be is obtained by using the core plus neutron type wave function: $|2s_{1\over 2}>+|1d_{5\over2}\times 2^+ ; {1/2}^{+}>$. A large hfs anomaly of $^{11}$Be is found, which is mainly due to a large radius of the halo single particle state.Comment: 14 pages, Late