Poynting's theorem and energy conservation in the propagation of light in bounded media

Starting from the Maxwell-Lorentz equations, Poynting's theorem is reconsidered. The energy flux vector is introduced as S_e=(E x B)/mu_0 instead of E x H, because only by this choice the energy dissipation can be related to the balance of the kinetic energy of the matter subsystem. Conservation of the total energy as the sum of kinetic and electromagnetic energy follows. In our discussion, media and their microscopic nature are represented exactly by their susceptibility functions, which do not necessarily have to be known. On this footing, it can be shown that energy conservation in the propagation of light through bounded media is ensured by Maxwell's boundary conditions alone, even for some frequently used approximations. This is demonstrated for approaches using additional boundary conditions and the dielectric approximation in detail, the latter of which suspected to violate energy conservation for decades.Comment: 5 pages, RevTeX4, changes: complete rewrit

Fifth Year Persisters: High School, College, and Early Career Outcomes For Persisting Non-Graduates

There is limited extant knowledge regarding academic and workforce experiences of students who remain engaged in high school, but do not graduate in the traditional four years. The current study used Multilevel modeling and descriptive statistics with statewide linked longitudinal administrative data (N = 2917) to (1) examine the student- and school-level factors related to earning a diploma during the fifth year of high school and (2) describe proximate academic and career outcomes for non-graduates and fifth year graduates. Multiple student-level factors were associated with increased likelihood of earning a diploma in the fifth year (e.g. special education eligibility, passing exit exams, higher attendance). Returning dropouts were less likely than persisters to earn a diploma in year five. In addition, the type and composition of the school a student attended affected the likelihood that a student would earn a diploma in year five. We also report population-level rates of participation in the workforce and postsecondary enrollment for fifth-year graduates and non-graduates. Fifth-year graduates outperformed non-graduates in both categories. Our findings provide insight into near term outcomes for students in a fifth-year of high school and suggest key factors that can be used for early identification and targeting services towards this under-researched and under-served population

Optical Resonances in Reflectivity near Crystal Modes with Spatial Dispersion

We study the effect of spatial dispersion of crystal modes on optical properties such as the reflectivity $R$. As an example for isotropic media, we investigate the simplest model for phonons in ionic crystals and compare with previous results for highly anisotropic plasmons, which are now understood from a more general point of view. As a consequence of the wave vector dependence of the dielectric function small changes in the lineshape are predicted. Beyond that, if the frequency of minimal $R$ is near a pole of the dispersionless dielectric function, the relative amplitude of dips in $R$ with normal and anomalous dispersion differ significantly, if dissipation and disorder are low.Comment: 4 pages, 7 eps figures, minor change

Ancestral mitogenome capture of the Southeast Asian banded linsang

Utilising a reconstructed ancestral mitochondrial genome of a clade to design hybridisation capture baits can provide the opportunity for recovering mitochondrial sequences from all its descendent and even sister lineages. This approach is useful for taxa with no extant close relatives, as is often the case for rare or extinct species, and is a viable approach for the analysis of historical museum specimens. Asiatic linsangs (genus Prionodon) exemplify this situation, being rare Southeast Asian carnivores for which little molecular data is available. Using ancestral capture we recover partial mitochondrial genome sequences for seven banded linsangs (P. linsang) from historical specimens, representing the first intraspecific genetic dataset for this species. We additionally assemble a high quality mitogenome for the banded linsang using shotgun sequencing for time-calibrated phylogenetic analysis. This reveals a deep divergence between the two Asiatic linsang species (P. linsang, P. pardicolor), with an estimated divergence of ~12 million years (Ma). Although our sample size precludes any robust interpretation of the population structure of the banded linsang, we recover two distinct matrilines with an estimated tMRCA of ~1 Ma. Our results can be used as a basis for further investigation of the Asiatic linsangs, and further demonstrate the utility of ancestral capture for studying divergent taxa without close relatives

Impact of heavy hole-light hole coupling on optical selection rules in GaAs quantum dots

We report strong heavy hole-light mixing in GaAs quantum dots grown by droplet epitaxy. Using the neutral and charged exciton emission as a monitor we observe the direct consequence of quantum dot symmetry reduction in this strain free system. By fitting the polar diagram of the emission with simple analytical expressions obtained from k$\cdot$p theory we are able to extract the mixing that arises from the heavy-light hole coupling due to the geometrical asymmetry of the quantum dot.Comment: 4 pages, 2 figure

Dopamine elevates and lowers astroglial Ca(2+) through distinct pathways depending on local synaptic circuitry

Whilst astrocytes in culture invariably respond to dopamine with cytosolic Ca(2+) rises, the dopamine sensitivity of astroglia in situ and its physiological roles remain unknown. To minimize effects of experimental manipulations on astroglial physiology, here we monitored Ca(2+) in cells connected via gap junctions to astrocytes loaded whole-cell with cytosolic indicators in area CA1 of acute hippocampal slices. Aiming at high sensitivity of [Ca(2+) ] measurements, we also employed life-time imaging of the Ca(2+) indicator Oregon Green BAPTA-1. We found that dopamine triggered a dose-dependent, bidirectional Ca(2+) response in stratum radiatum astroglia, a jagged elevation accompanied and followed by below-baseline decreases. The elevation depended on D1/D2 receptors and engaged intracellular Ca(2+) storage and removal whereas the dopamine-induced [Ca(2+) ] decrease involved D2 receptors only and was sensitive to Ca(2+) channel blockade. In contrast, the stratum lacunosum moleculare astroglia generated higher-threshold dopamine-induced Ca(2+) responses which did not depend on dopamine receptors and were uncoupled from the prominent inhibitory action of dopamine on local perforant path synapses. Our findings thus suggest that a single neurotransmitter-dopamine-could either elevate or decrease astrocyte [Ca(2+) ] depending on the receptors involved, that such actions are specific to the regional neural circuitry and that they may be causally uncoupled from dopamine actions on local synapses. The results also indicate that [Ca(2+) ] elevations commonly detected in astroglia can represent the variety of distinct mechanisms acting on the microscopic scale. GLIA 2016

Optical Properties of Crystals with Spatial Dispersion: Josephson Plasma Resonance in Layered Superconductors

We derive the transmission coefficient, $T(\omega)$, for grazing incidence of crystals with spatial dispersion accounting for the excitation of multiple modes with different wave vectors ${\bf k}$ for a given frequency $\omega$. The generalization of the Fresnel formulas contains the refraction indices of these modes as determined by the dielectric function $\epsilon(\omega,{\bf k})$. Near frequencies $\omega_e$, where the group velocity vanishes, $T(\omega)$ depends also on an additional parameter determined by the crystal microstructure. The transmission $T$ is significantly suppressed, if one of the excited modes is decaying into the crystal. We derive these features microscopically for the Josephson plasma resonance in layered superconductors.Comment: 4 pages, 2 figures, epl.cls style file, minor change

Risk factors for respiratory work disability in a cohort of pulp mill workers exposed to irritant gases

<p>Abstract</p> <p>Background</p> <p>The association between chronic respiratory diseases and work disability has been demonstrated a number of times over the past 20 years, but still little is known about work disability in occupational cohorts of workers exposed to respiratory irritants. This study investigated job or task changes due to respiratory problems as an indicator of work disability in pulp mill workers occupationally exposed to irritants.</p> <p>Methods</p> <p>Data about respiratory symptoms and disease diagnoses, socio-demographic variables, occupational exposures, gassing episodes, and reported work changes due to respiratory problems were collected using a questionnaire answered by 3226 pulp mill workers. Information about work history and departments was obtained from personnel files. Incidence and hazard ratios for respiratory work disability were calculated with 95% confidence intervals (CI).</p> <p>Results</p> <p>The incidence of respiratory work disability among these pulp mill workers was 1.6/1000 person-years. The hazard ratios for respiratory work disability were increased for workers reporting gassings (HR 5.3, 95% CI 2.7-10.5) and for those reporting physician-diagnosed asthma, chronic bronchitis, and chronic rhinitis, when analyzed in the same model.</p> <p>Conclusions</p> <p>This cohort study of pulp mill workers found that irritant peak exposure during gassing episodes was a strong predictor of changing work due to respiratory problems, even after adjustment for asthma, chronic bronchitis, and chronic rhinitis.</p