Faraday Rotation, Band Splitting, and One-Way Propagation of Plasmon Waves on a Nanoparticle Chain

We calculate the dispersion relations of plasmonic waves propagating along a chain of semiconducting or metallic nanoparticles in the presence of both a static magnetic field ${\bf B}$ and a liquid crystalline host. The dispersion relations are obtained using the quasistatic approximation and a dipole-dipole approximation to treat the interaction between surface plasmons on different nanoparticles. For a plasmons propagating along a particle chain in a nematic liquid crystalline host with both ${\bf B}$ and the director parallel to the chain, we find a small, but finite, Faraday rotation angle. For ${\bf B}$ perpendicular to the chain, but director still parallel to the chain, the field couples the longitudinal and one of the two transverse plasmonic branches. This coupling is shown to split the two branches at the zero field crossing by an amount proportional to $|{\bf B}|$. In a cholesteric liquid crystal host and an applied magnetic field parallel to the chain, the dispersion relations for left- and right-moving waves are found to be different. For some frequencies, the plasmonic wave propagates only in one of the two directions.Comment: 6 pages, 4 figures. arXiv admin note: substantial text overlap with arXiv:1502.0496

Tight-Binding Model for Adatoms on Graphene: Analytical Density of States, Spectral Function, and Induced Magnetic Moment

In the limit of low adatom concentration, we obtain exact analytic expressions for the local and total density of states (LDOS, TDOS) for a tight-binding model of adatoms on graphene. The model is not limited to nearest-neighbor hopping but can include hopping between carbon atoms at any separation. We also find an analytical expression for the spectral function $A({\bf k}, E)$ of an electron of Bloch vector ${\bf k}$ and energy E on the graphene lattice, to first order in the adatom concentration. We treat the electron-electron interaction by including a Hubbard term on the adatom, which we solve within a mean-field approximation. For finite Hubbard $U$, we find the spin-polarized LDOS, TDOS, and spectral function self-consistently. For any choice of parameters of the tight-binding model within mean field theory, we find a critical value of $U$ above which a moment develops on the adatom. For most choices of parameters, we find a substantial charge transfer from the adatom to the graphene host.Comment: 11 Pages, 6 figures, 1 tabl

Forecasting the public finances in the Treasury

This article describes the methods used by the Treasury and other government departments for making forecasts of the public finances. A highly detailed approach is required because of the Treasury’s budgetary role, but the aggregated results are subjected to careful ‘top-down’ checks. Forecasts have a necessary role in fiscal policy. But they are subject to large margins of error, and should be presented and used with caution.

Japan\u27s “comfort women”: No end to the struggle

In 2010 two basic questions remained unresolved. Did the Comfort Women number in the hundreds, or in the hundreds of thousands? Were the Comfort Women enslaved by private local enterprises, or by the Japanese military following instructions from the Japanese Government

Do Teachers Know This?

A Communication Arts instructor in a Calgary Technical Institute discovers an opportunity to enlarge his vocation when a student asks him a simple four-word question. Methods of thinking and learning are soon integrated into the communications curriculum, and students, together with their instructors, are invited to develop more and better “TLC” capabilities as they study and practice their chosen disciplines. The article closes by suggesting, given the challenges we’re facing in working, learning, and living well together now, that we ask leaders in our communities and beyond the same question; and to encourage them to expand their leadership roles and the roles of the people they lead, focusing less on what to think, learn, and communicate, and more on how

Forecasting the viability of sea turtle eggs in a warming world

Animals living in tropical regions may be at increased risk from climate change because current temperatures at these locations already approach critical physiological thresholds. Relatively small temperature increases could cause animals to exceed these thresholds more often, resulting in substantial fitness costs or even death. Oviparous species could be especially vulnerable because the maximum thermal tolerances of incubating embryos is often lower than adult counterparts, and in many species mothers abandon the eggs after oviposition, rendering them immobile and thus unable to avoid extreme temperatures. As a consequence, the effects of climate change might become evident earlier and be more devastating for hatchling production in the tropics. Loggerhead sea turtles (Caretta caretta) have the widest nesting range of any living reptile, spanning temperate to tropical latitudes in both hemispheres. Currently, loggerhead sea turtle populations in the tropics produce nearly 30% fewer hatchlings per nest than temperate populations. Strong correlations between empirical hatching success and habitat quality allowed global predictions of the spatiotemporal impacts of climate change on this fitness trait. Under climate change, many sea turtle populations nesting in tropical environments are predicted to experience severe reductions in hatchling production, whereas hatching success in many temperate populations could remain unchanged or even increase with rising temperatures. Some populations could show very complex responses to climate change, with higher relative hatchling production as temperatures begin to increase, followed by declines as critical physiological thresholds are exceeded more frequently. Predicting when, where, and how climate change could impact the reproductive output of local populations is crucial for anticipating how a warming world will influence population size, growth, and stability

An Analysis of Factors Associated with the Change in Graduation Requirements at Champaign Centennial High School

The graduation requirements for the students at Champaign Centennial High School, Champaign, Illinois, changed effective with the class of 1988. This field experience investigated the possible effects of the new and more stringent graduation requirements. A comparative analysis using students in the classes of 1985, 1986, and 1987 for the baseline data with the students in the classes of 1988 and 1989 was completed. Specifically, the evaluator designed a procedure to statistically study the students\u27 American College Test and SRA Survey of Basic Skills Test scores. A two tailed t-test for the difference of the means at the .05 level of significance was used to analyze the data collected. Results of the study indicate that after the change in graduation requirements there were no statistically significant differences on student achievement as determined by scores on the two tests. The study also examined graduation rates, dropout rates, transfer-in rates, and transfer-out rates before and after the change in graduation requirements. After implementation of the new requirements, graduation rates increased and dropout rates decreased while the percentage of students transferring out increased. A higher percentage of transfer-in students graduated after the increase in graduation requirements