The "Binarity and Magnetic Interactions in various classes of Stars" (BinaMIcS) project

The "Binarity and Magnetic Interactions in various classes of stars" (BinaMIcS) project is based on two large programs of spectropolarimetric observations with ESPaDOnS at CFHT and Narval at TBL. Three samples of spectroscopic binaries with two spectra (SB2) are observed: known cool magnetic binaries, the few known hot magnetic binaries, and a survey sample of hot binaries to search for additional hot magnetic binaries. The goal of BinaMIcS is to understand the complex interplay between stellar magnetism and binarity. To this aim, we will characterise and model the magnetic fields, magnetospheric structure and coupling of both components of hot and cool close binary systems over a significant range of evolutionary stages, to confront current theories and trigger new ones. First results already provided interesting clues, e.g. about the origin of magnetism in hot stars.Comment: 4 pages, 2 figures, proceedings of the SF2A conferenc

Cuidado de enfermagem para enfermeiros docentes na perspectiva da complexidade

O cuidado de enfermagem complexo é condição essencial para a compreensão do ser humano como singular e multidimensional. Assim, objetivou-se conhecer o significado do cuidado de enfermagem para enfermeiros docentes, na perspectiva da complexidade. Trata-se de uma pesquisa qualitativa, realizada com sete enfermeiros docentes deum curso de enfermagem de nível superior da região central do Rio Grande do Sul, Brasil. Os dados foram coletados no mês de novembro de 2011, por meio do grupo focal, a partir de três encontros, sistematizados com temáticas que contemplassem o objetivo deste estudo. Para a análise de dados, foi utilizada a análise textual discursiva. Os resultados evidenciaram o cuidado de enfermagem como construção singular que vai além de um cuidado técnico-prescritivo, pontual e linear. Conclui-se que o cuidado de enfermagem não pode ser concebido como açãoreducionista, mas como construção singular, que envolve interações, reflexões e autoconhecimento

Thermodynamic metrics and optimal paths

A fundamental problem in modern thermodynamics is how a molecular-scale machine performs useful work, while operating away from thermal equilibrium without excessive dissipation. To this end, we derive a friction tensor that induces a Riemannian manifold on the space of thermodynamic states. Within the linear-response regime, this metric structure controls the dissipation of finite-time transformations, and bestows optimal protocols with many useful properties. We discuss the connection to the existing thermodynamic length formalism, and demonstrate the utility of this metric by solving for optimal control parameter protocols in a simple nonequilibrium model.Comment: 5 page

Random replicators with high-order interactions

We use tools of the equilibrium statistical mechanics of disordered systems to study analytically the statistical properties of an ecosystem composed of N species interacting via random, Gaussian interactions of order p >= 2, and deterministic self-interactions u <= 0. We show that for nonzero u the effect of increasing the order of the interactions is to make the system more cooperative, in the sense that the fraction of extinct species is greatly reduced. Furthermore, we find that for p > 2 there is a threshold value which gives a lower bound to the concentration of the surviving species, preventing then the existence of rare species and, consequently, increasing the robustness of the ecosystem to external perturbations.Comment: 7 pages, 4 Postscript figure

A universal optical all-fiber omnipolarizer

Wherever the polarization properties of a light beam are of concern, polarizers and polarizing beamsplitters (PBS) are indispensable devices in linear-, nonlinear-and quantum-optical schemes. By the very nature of their operation principle, transformation of incoming unpolarized or partially polarized beams through these devices introduces large intensity variations in the fully polarized outcoming beam(s). Such intensity fluctuations are often detrimental, particularly when light is post-processed by nonlinear crystals or other polarization-sensitive optic elements. Here we demonstrate the unexpected capability of light to self-organize its own state-of-polarization, upon propagation in optical fibers, into universal and environmentally robust states, namely right and left circular polarizations. We experimentally validate a novel polarizing device-the Omnipolarizer, which is understood as a nonlinear dual-mode polarizing optical element capable of operating in two modes-as a digital PBS and as an ideal polarizer. Switching between the two modes of operation requires changing beam's intensity

Nonperturbative Matching for Field Theories with Heavy Fermions

We examine a paradox, suggested by Banks and Dabholkar, concerning nonperturbative effects in an effective field theory which is obtained by integrating out a generation of heavy fermions, where the heavy fermion masses arise from Yukawa couplings. They argue that light fermions in the effective theory appear to decay via instanton processes, whereas their decay is forbidden in the full theory. We resolve this paradox by showing that such processes in fact do not occur in the effective theory, due to matching corrections which cause the relevant light field configurations to have infinite action.Comment: 10 pages, no figures, uses harvmac, Harvard University Preprint HUTP-93/A03

Activity and Magnetic Field Structure of the Sun-Like Planet Hosting Star HD 1237

We analyse the magnetic activity characteristics of the planet hosting Sun-like star, HD 1237, using HARPS spectro-polarimetric time-series data. We find evidence of rotational modulation of the magnetic longitudinal field measurements consistent with our ZDI analysis, with a period of 7 days. We investigate the effect of customising the LSD mask to the line depths of the observed spectrum and find that it has a minimal effect on shape of the extracted Stokes V profile but does result in a small increase in the S/N ($\sim$ 7%). We find that using a Milne-Eddington solution to describe the local line profile provides a better fit to the LSD profiles in this slowly rotating star, which also impacts the recovered ZDI field distribution. We also introduce a fit-stopping criterion based on the information content (entropy) of the ZDI maps solution set. The recovered magnetic field maps show a strong (+90 G) ring-like azimuthal field distribution and a complex radial field dominating at mid latitudes ($\sim$45 degrees). Similar magnetic field maps are recovered from data acquired five months apart. Future work will investigate how this surface magnetic field distribution impacts the coronal magnetic field and extended environment around this planet-hosting star.Comment: Accepted for publication in A&