Triton's global heat budget

Internal heat flow from radioactive decay in Triton's interior along with absorbed thermal energy from Neptune total 5 to 20 percent of the insolation absorbed by Triton, thus comprising a significant fraction of Triton's surface energy balance. These additional energy inputs can raise Triton's surface temperature between approx. 0.5 to 1.5 K above that possible with absorbed sunlight alone, resulting in a factor of approx. 1.5 to 2.5 increase in Triton's basal atmospheric pressure. If Triton's internal heatflow is concentrated in some areas, as is likely, local effects such as enhanced sublimation with subsequent modification of albedo could be quite large. Furthermore, indications of recent albedo change on Triton suggest that Triton's surface temperature and pressure may not now be in steady state, further suggesting that atmospheric pressure on Triton was as much as 10 times higher in the recent past

Dynamic polarizabilities and related properties of clock states of ytterbium atom

We carry out relativistic many-body calculations of the static and dynamic dipole polarizabilities of the ground 6s^2 ^1S_0 and the first excited $6s6p ^3P^o_0$ states of Yb. With these polarizabilities, we compute several properties of Yb relevant to optical lattice clocks operating on the 6s^2 ^1S_0 - 6s6p ^3P^o_0 transition. We determine (i) the first four {\em magic} wavelengths of the laser field for which the frequency of the clock transition is insensitive to the laser intensity. While the first magic wavelength is known, we predict the second, the third and the forth magic wavelengths to be 551 nm, 465 nm, and 413 nm. (ii) We reevaluate the effect of black-body radiation on the frequency of the clock transition, the resulting clock shift at $T=300 \mathrm{K}$ being $-1.41(17)$ Hz. (iii) We compute long-range interatomic van der Waals coefficients (in a.u.) C_6(6s^2 ^1S_0 +6s^2 ^1S_0) = 1909(160), C_6(6s^2 ^1S_0 + 6s6p ^3P_0) =2709(338) , and $C_6(6s6p ^3P_0 + 6s6p ^3P_0) =3886(360)$. Finally, we determine the atom-wall interaction coefficients (in a.u.), C_3 (6s^2 ^1S_0) =3.34 and $C_3 (6s6p ^3P_0) =3.68$. We also address and resolve a disagreement between previous calculations of the static polarizability of the ground state.Comment: 11 pages, 1 figur

Teaching Social Justice Lawyering: Systematically Including Community Legal Education in Law School Clinics

There is a body of literature on clinical legal theory that urges a focus in clinics beyond the single client to an explicit teaching of social justice lawyering. This Article adds to this emerging body of work by discussing the valuable role community legal education plays as a vehicle for teaching skills and values essential to single client representation and social justice lawyering. The Article examines the theoretical underpinnings of clinical legal education, community organizing and community education and how they influenced the authors’ design and implementation of community legal education within their clinics. It then discusses two projects designed to help victims of domestic violence. The first project has been ongoing for several years in a clinic with a long history of incorporating community education into its work. The second project was undertaken for the first time by a clinic teaching community legal education after a long hiatus. Through the discussion of these two projects, the Article evaluates and explains the pedagogical and logistical successes and challenges of incorporating community education into clinical programs and assesses the justice outcomes of their community work, both to the communities served and to their students

Vector bundles on the projective line and finite domination of chain complexes

Finitely dominated chain complexes over a Laurent polynomial ring in one indeterminate are characterised by vanishing of their Novikov homology. We present an algebro-geometric approach to this result, based on extension of chain complexes to sheaves on the projective line. We also discuss the K-theoretical obstruction to extension.Comment: v1: 11 page

Waveguiding properties of surface states in photonic crystals

We propose and analyze novel surface-state-based waveguides in bandgap photonic crystals. We discuss surface mode band structure, field localization and effect of imperfections on the waveguiding properties of the surface modes. We demonstrate that surface-state-based waveguides can be used to achieve directional emission out of the waveguide. We also discuss the application of the surface-state waveguides as efficient light couplers for conventional photonic crystal waveguides.Comment: 4 pages 5 figure

Bilirubin Present in Diverse Angiosperms

Background and aims: Bilirubin is an orange-yellow tetrapyrrole produced from the breakdown of heme by mammals and some other vertebrates. Plants, algae, and cyanobacteria synthesize molecules similar to bilirubin, including the protein-bound bilins and phytochromobilin which harvest or sense light. Recently, we discovered bilirubin in the arils of Strelitzia nicolai, the White Bird of Paradise Tree, which was the first example of this molecule in a higher plant. Subsequently, we identified bilirubin in both the arils and flowers of Strelitzia reginae, the Bird of Paradise Flower. In the arils of both species, bilirubin is present as the primary pigment, and thus functions to produce color. Previously, no tetrapyrroles were known to generate display color in plants. We were therefore interested in determining whether bilirubin is broadly distributed in the plant kingdom, and whether it contributes to color in other species

Multiple scattering of polarized radiation by non-spherical grains: first results

We present the first numerical radiative transfer simulation of multiple light scattering in dust configurations containing aligned non-spherical (spheroidal) dust grains. Such models are especially important if one wants to explain the circular polarization of light, observed in a variety of astronomical objects. The radiative transfer problem is solved on the basis of the Monte Carlo method. Test simulations, confirming the correct numerical implementation of the scattering mechanism, are presented. As a first application, we investigate the linear and circular polarization of light coming from a spherical circumstellar shell. This shell contains perfectly aligned prolate or oblate spheroidal grains. The most remarkable features of the simulated linear polarization maps are so-called polarization null points where the reversal of polarization occurs. They appear in the case when the grain alignment axis is perpendicular to the line of sight. The maps of circular polarization have a sector-like structure with maxima at the ends of lines inclined to the grain alignment axis by \pm 45\degr.Comment: 13 pages, 14 figures, accepted by A&

Electric-octupole and pure-electric-quadrupole effects in soft-x-ray photoemission

Second-order [O(k^2), k=omega/c] nondipole effects in soft-x-ray photoemission are demonstrated via an experimental and theoretical study of angular distributions of neon valence photoelectrons in the 100--1200 eV photon-energy range. A newly derived theoretical expression for nondipolar angular distributions characterizes the second-order effects using four new parameters with primary contributions from pure-quadrupole and octupole-dipole interference terms. Independent-particle calculations of these parameters account for a significant portion of the existing discrepancy between experiment and theory for Ne 2p first-order nondipole parameters.Comment: 4 pages, 3 figure

Emerging from the third space chrysalis: Experiences in a non-hierarchical, collaborative research community of practice

This article discusses the creation of a research-focused virtual community of practice (vCoP) for geographically-dispersed third space professionals, motivated by desires for enhanced professional collaboration, visibility and identity. The authors used collaborative autoethnography (CAE) to evaluate their personal reflections as vCoP participants. Data were gathered in two collaborative writing activities and analysed using thematic analysis (TA). The TA identified two connected themes, which capture the vCoP members’ aspirations to transcend their current roles and be research-active through connecting with like-minded professionals. Collaborative writing activities, including authoring this paper, cultivated elements of academic identity such as independence and purpose. A non-hierarchical and supportive vCoP environment allowed the members to work beyond time and institutional constraints to foster the evolution of the community and an emerging sense of professional identity beyond that typically associated with third space roles. The paper offers a model of collaboration that could help groups in similar situations