Beamed Lyman Alpha Emission through Outflow-Driven Cavities

We investigate the radiative transfer of Lyman alpha photons through simplified anisotropic gas distributions, which represent physically motivated extensions of the popular 'shell-models'. Our study is motivated by the notion that (i) shell models do not always reproduce observed Lyman alpha spectral line profiles, (ii) (typical) shell models do not allow for the escape of ionizing photons, and (iii) the observation & expectation that winds are more complex, anisotropic phenomena. We examine the influence of inclination on the Lyman alpha spectra, relative fluxes and escape fractions. We find the flux to be enhanced/suppressed by factors up to a few depending on the parameter range of the models, corresponding to a boost in equivalent width of the same amplitude if we neglect dust. In general, lower mean optical depths tend to reduce the impact of anisotropies as is expected. We find a correlation between an observed peak in the -- occasionally triple-peaked -- spectrum at the systemic velocity and the existence of a low optical depth cavity along the line of sight. This can be of importance in the search for ionizing photons leaking from high- redshift galaxies since these photons will also be able to escape through the cavity.Comment: 11 pages, accepted for publication in A&

Keeping Humans Out of the Picture: The (Almost) Pristine Wilderness of The Last of the Mohicans

This article examines the depiction of the wilderness in James Fenimore Cooper’s The Last of the Mohicans. It begins by recalling that in the early decades of the nineteenth century, descriptions of pristine landscapes were relatively common in American writings, whose authors were often striving to create a distinctively national literature for the new country. Cooper drew on the traditions of the picturesque and the sublime and made use of “painterly” techniques to create a “constructed” wilderness setting for his romance. By 1826, however, when the book was published, the American environment was already in the process of significant transformation, not to say devastation, brought about by human activity. And some people, including Cooper, were already decrying this destruction. In The Last of the Mohicans, however, the author does not address environmental questions directly, as he had, for example, in his previous work, The Pioneers, but rather offers an image of untouched nature—of the way things used to be. Cooper does nevertheless incorporate reminders—which are all marginalized in one way or another to keep them out of the literary picture he creates—of the fact that the American landscape was already in the process of undergoing disfiguring change.Cet article examine la représentation de la nature sauvage dans Le Dernier des Mohicans de James Fenimore Cooper. Il commence par rappeler que pendant les premières décennies du dix-neuvième siècle des descriptions de paysages vierges apparaissaient relativement souvent dans les écrits américains, dont les auteurs contribuaient souvent à la création d’une littérature nationale caractéristique pour le nouveau pays. Cooper faisait appel aux traditions du pittoresque et du sublime, ainsi qu’aux techniques « picturales » pour créer un décor sauvage « construit » pour son roman. En 1826, cependant, quand le livre fut publié, l’environnement américain était déjà en train d’être transformé, pour ne pas dire dévasté, par l’activité humaine. Et certains, dont Cooper, décriaient déjà cette destruction. Dans Le Dernier des Mohicans, pourtant, l’auteur ne traite pas directement les questions environnementales, comme il l’a fait, par exemple, dans son œuvre précédente, Les Pionniers, mais offre plutôt une image d’une nature à l’état pur, une image, en fait, du passé. Cooper néanmoins incorpore des rappels – qui sont tous marginalisés d’une façon ou une autre pour les garder à l’extérieur du tableau littéraire qu’il crée – du fait que le paysage américain était déjà en train de subir une défiguration irréversible

Ronan Ludot-Vlasak, La Réinvention de Shakespeare sur la scène littéraire américaine

La Réinvention de Shakespeare sur la scène littéraire américaine (1798-1857) de Ronan Ludot-Vlasak offre une analyse détaillée et très intéressante de la place de William Shakespeare - l’homme et l’œuvre - dans la littérature américaine de la première moitié du XIXe siècle (plus précisément de 1798, date de la publication de Wieland; or, the Transformation de Charles Brockden Brown, à 1857, celle de The Confidence-Man: His Masquerade d’Herman Melville). C’est pendant cette période que les nat..

Marc Amfreville. Charles Brockden Brown. La part du doute.

La collection « Voix américaines » remonte cette fois-ci jusqu’au tout début de la littérature des Etats-Unis. Né en 1771, juste avant la guerre d’Indépendance, Charles Brockden Brown, sujet de ce volume, publia six romans (Wieland, Ormond, Arthur Mervyn, Edgar Huntly, Jane Talbot et Clara Howard) entre 1798 et 1801. Il n’est pas véritablement le premier romancier américain, car ce titre devrait plutôt revenir à William Hill Brown dont The Power of Sympathy parut en 1789. Charles Brockden Bro..

Ronan Ludot-Vlasak, La Réinvention de Shakespeare sur la scène littéraire américaine

La Réinvention de Shakespeare sur la scène littéraire américaine (1798-1857) de Ronan Ludot-Vlasak offre une analyse détaillée et très intéressante de la place de William Shakespeare - l’homme et l’œuvre - dans la littérature américaine de la première moitié du XIXe siècle (plus précisément de 1798, date de la publication de Wieland; or, the Transformation de Charles Brockden Brown, à 1857, celle de The Confidence-Man: His Masquerade d’Herman Melville). C’est pendant cette période que les nat..

Thomas Constantinesco, Writing Pain in the Nineteenth-Century United States

Pain is part of life. It is part of literature as well. And in Writing Pain in the Nineteenth-Century United States, Thomas Constantinesco offers an intelligent, clearly organized, and insightful exploration of various ways in which pain is expressed—or not—through the written word in a selection of American literary works from the 1800s. Constantinesco takes his initial inspiration, in part, from Elaine Scarry’s The Body in Pain, a controversial work published in 1985, which has become recog..

Structural Design and Analysis of a Light-Weight Laminated Composite Heat Sink for Spaceflight PWBs

In order to reduce the overall weight in spaceborne electronic systems, a conventional metallic heat sink typically used for double-sided printed wiring boards was suggested to be replaced by light-weight and high-strength laminated composite materials. Through technology validation assurance (TVA) approach, it has been successfully demonstrated that using laminated composite heat sink can not only reduce the weight of the heat sink by nearly 50%, but also significantly lower the internal thermally-induced stresses that are largely responsible for potential delamination under cyclic temperature variations. With composite heat sink, both thermal and dynamic performance of the double-sided printed wiring board (PWB) exceeds that of its counterpart with metallic heat sink. Also included in this work is the original contribution to the understanding of creep behavior of the worst-case leadless chip carrier (LCC) surface mount solder joint. This was identified as the interconnection most susceptible to thermal fatigue damage in the PWB assembly

Report on the Third Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE3)

This report records and discusses the Third Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE3). The report includes a description of the keynote presentation of the workshop, which served as an overview of sustainable scientific software. It also summarizes a set of lightning talks in which speakers highlighted to-the-point lessons and challenges pertaining to sustaining scientific software. The final and main contribution of the report is a summary of the discussions, future steps, and future organization for a set of self-organized working groups on topics including developing pathways to funding scientific software; constructing useful common metrics for crediting software stakeholders; identifying principles for sustainable software engineering design; reaching out to research software organizations around the world; and building communities for software sustainability. For each group, we include a point of contact and a landing page that can be used by those who want to join that group's future activities. The main challenge left by the workshop is to see if the groups will execute these activities that they have scheduled, and how the WSSSPE community can encourage this to happen

VIPP2 interacts with VIPP1 and HSP22E/F at chloroplast membranes and modulates a retrograde signal for HSP22E/F gene expression

VIPP proteins aid thylakoid biogenesis and membrane maintenance in cyanobacteria, algae, and plants. Some members of the Chlorophyceae contain two VIPP paralogs termed VIPP1 and VIPP2, which originate from an early gene duplication event during the evolution of green algae. VIPP2 is barely expressed under nonstress conditions but accumulates in cells exposed to high light intensities or H2O2, during recovery from heat stress, and in mutants with defective integration (alb3.1) or translocation (secA) of thylakoid membrane proteins. Recombinant VIPP2 forms rod-like structures in vitro and shows a strong affinity for phosphatidylinositol phosphate. Under stress conditions, >70% of VIPP2 is present in membrane fractions and localizes to chloroplast membranes. A vipp2 knock-out mutant displays no growth phenotypes and no defects in the biogenesis or repair of photosystem II. However, after exposure to high light intensities, the vipp2 mutant accumulates less HSP22E/F and more LHCSR3 protein and transcript. This suggests that VIPP2 modulates a retrograde signal for the expression of nuclear genes HSP22E/F and LHCSR3. Immunoprecipitation of VIPP2 from solubilized cells and membrane-enriched fractions revealed major interactions with VIPP1 and minor interactions with HSP22E/F. Our data support a distinct role of VIPP2 in sensing and coping with chloroplast membrane stress