Mantle formation, coagulation and the origin of cloud/core-shine: II. Comparison with observations

Many dense interstellar clouds are observable in emission in the near-IR, commonly referred to as "Cloudshine", and in the mid-IR, the so-called "Coreshine". These C-shine observations have usually been explained with grain growth but no model has yet been able to self-consistently explain the dust spectral energy distribution from the near-IR to the submm. We want to demonstrate the ability of our new core/mantle evolutionary dust model THEMIS (The Heterogeneous dust Evolution Model at the IaS), which has been shown to be valid in the far-IR and submm, to reproduce the C-shine observations. Our starting point is a physically motivated core/mantle dust model. It consists of 3 dust populations: small aromatic-rich carbon grains; bigger core/mantle grains with mantles of aromatic-rich carbon and cores either made of amorphous aliphatic-rich carbon or amorphous silicate. We assume an evolutionary path where these grains, when entering denser regions, may first form a second aliphatic-rich carbon mantle (coagulation of small grains, accretion of carbon from the gas phase), second coagulate together to form large aggregates, and third accrete gas phase molecules coating them with an ice mantle. To compute the corresponding dust emission and scattering, we use a 3D Monte-Carlo radiative transfer code. We show that our global evolutionary dust modelling approach THEMIS allows us to reproduce C-shine observations towards dense starless clouds. Dust scattering and emission is most sensitive to the cloud central density and to the steepness of the cloud density profile. Varying these two parameters leads to changes, which are stronger in the near-IR, in both the C-shine intensity and profile. With a combination of aliphatic-rich mantle formation and low-level coagulation into aggregates, we can self-consistently explain the observed C-shine and far-IR/submm emission towards dense starless clouds.Comment: Paper accepted for publication in A&A with companion paper "Mantle formation, coagulation and the origin of cloud/core-shine: I. Dust scattering and absorption in the IR", A.P Jones, M. Koehler, N. Ysard, E. Dartois, M. Godard, L. Gavila

Submuscular transposition with musculofascial lengthening for persistent or recurrent cubital tunnel syndrome in 34 patients

The two main surgical options for patients with persistent or recurrent cubital tunnel syndrome are subcutaneous and submuscular transposition. We retrospectively analysed the results of 34 patients with recalcitrant cubital tunnel syndrome who underwent submuscular transposition with musculofascial lengthening at our institutions. Of the 34 patients, 21 improved clinically after submuscular transposition with musculofascial lengthening, of which 16 were still satisfied at a mean follow-up of four years. In addition, all articles published between 1974 and January 2015 on subcutaneous and/or submuscular transposition of the ulnar nerve for recalcitrant cubital tunnel syndrome were reviewed. We found that previously published studies on this subject are too heterogeneous to compare. No recommendation can thus be made regarding the surgical technique for persistent or recurrent cubital tunnel syndrome. Our series shows that the musculofascial lengthening technique for submuscular transposition is a good option. More research is needed to compare the different surgical treatments. Level of evidence: IV

OH+ in astrophysical media: state-to-state formation rates, Einstein coefficients and inelastic collision rates with He

The rate constants required to model the OH$^+$ observations in different regions of the interstellar medium have been determined using state of the art quantum methods. First, state-to-state rate constants for the H$_2(v=0,J=0,1)$+ O$^+$($^4S$) $\rightarrow$ H + OH$^+(X ^3\Sigma^-, v', N)$ reaction have been obtained using a quantum wave packet method. The calculations have been compared with time-independent results to asses the accuracy of reaction probabilities at collision energies of about 1 meV. The good agreement between the simulations and the existing experimental cross sections in the $0.01-$1 eV energy range shows the quality of the results. The calculated state-to-state rate constants have been fitted to an analytical form. Second, the Einstein coefficients of OH$^+$ have been obtained for all astronomically significant ro-vibrational bands involving the $X^3\Sigma^-$ and/or $A^3\Pi$ electronic states. For this purpose the potential energy curves and electric dipole transition moments for seven electronic states of OH$^+$ are calculated with {\it ab initio} methods at the highest level and including spin-orbit terms, and the rovibrational levels have been calculated including the empirical spin-rotation and spin-spin terms. Third, the state-to-state rate constants for inelastic collisions between He and OH$^+(X ^3\Sigma^-)$ have been calculated using a time-independent close coupling method on a new potential energy surface. All these rates have been implemented in detailed chemical and radiative transfer models. Applications of these models to various astronomical sources show that inelastic collisions dominate the excitation of the rotational levels of OH$^+$. In the models considered the excitation resulting from the chemical formation of OH$^+$ increases the line fluxes by about 10 % or less depending on the density of the gas

Mantle formation, coagulation and the origin of cloud/core shine: I. Modelling dust scattering and absorption in the infra-red

Context. The observed cloudshine and coreshine (C-shine) have been explained in terms of grain growth leading to enhanced scatter- ing from clouds in the J, H and K photometric bands and the Spitzer IRAC 3.6 and 4.5 {\mu}m bands. Aims. Using our global dust modelling approach THEMIS (The Heterogeneous dust Evolution Model at the IaS) we explore the effects of dust evolution in dense clouds, through aliphatic-rich carbonaceous mantle formation and grain-grain coagulation. Methods. We model the effects of wide band gap a-C:H mantle formation and the low-level aggregation of diffuse interstellar medium dust in the moderately-extinguished outer regions of molecular clouds. Results. The formation of wide band gap a-C:H mantles on amorphous silicate and amorphous carbon (a-C) grains leads to a decrease in their absorption cross-sections but no change in their scattering cross-sections at near-IR wavelengths, resulting in higher albedos. Conclusions. The evolution of dust, with increasing density and extinction in the diffuse to dense molecular cloud transition, through mantle formation and grain aggregation, appears to be a likely explanation for the observed C-shine.Comment: 12 pages, 15 figures, accepted for publication in A&A along with the companion paper entitled, Mantle formation, coagulation and the origin of cloud/core shine: II Comparison with observations, by Ysard et al. (also accepted for publication in A&A

A Very Low Resource Language Speech Corpus for Computational Language Documentation Experiments

Most speech and language technologies are trained with massive amounts of speech and text information. However, most of the world languages do not have such resources or stable orthography. Systems constructed under these almost zero resource conditions are not only promising for speech technology but also for computational language documentation. The goal of computational language documentation is to help field linguists to (semi-)automatically analyze and annotate audio recordings of endangered and unwritten languages. Example tasks are automatic phoneme discovery or lexicon discovery from the speech signal. This paper presents a speech corpus collected during a realistic language documentation process. It is made up of 5k speech utterances in Mboshi (Bantu C25) aligned to French text translations. Speech transcriptions are also made available: they correspond to a non-standard graphemic form close to the language phonology. We present how the data was collected, cleaned and processed and we illustrate its use through a zero-resource task: spoken term discovery. The dataset is made available to the community for reproducible computational language documentation experiments and their evaluation.Comment: accepted to LREC 201

Closed-loop separation control over a sharp edge ramp using Genetic Programming

We experimentally perform open and closed-loop control of a separating turbulent boundary layer downstream from a sharp edge ramp. The turbulent boundary layer just above the separation point has a Reynolds number $Re_{\theta}\approx 3\,500$ based on momentum thickness. The goal of the control is to mitigate separation and early re-attachment. The forcing employs a spanwise array of active vortex generators. The flow state is monitored with skin-friction sensors downstream of the actuators. The feedback control law is obtained using model-free genetic programming control (GPC) (Gautier et al. 2015). The resulting flow is assessed using the momentum coefficient, pressure distribution and skin friction over the ramp and stereo PIV. The PIV yields vector field statistics, e.g. shear layer growth, the backflow area and vortex region. GPC is benchmarked against the best periodic forcing. While open-loop control achieves separation reduction by locking-on the shedding mode, GPC gives rise to similar benefits by accelerating the shear layer growth. Moreover, GPC uses less actuation energy.Comment: 24 pages, 24 figures, submitted to Experiments in Fluid

Airway remodelling assessed by sputum and high resolution computed tomography in asthma and COPD

It is not known whether sputum elastase, metalloproteinase (MMP)-9 and tissue-inhibitor metalloproteinase (TIMP)-1 are related to structural changes of the airways, as assessed by high-resolution computed tomography (HRCT) scan. The relationships between these markers and the magnitude of structural changes of the airways in asthma and chronic obstructive pulmonary disease (COPD) were assessed. Induced sputum and HRCT scan were performed in 30 asthmatics (14 mild and 16 severe) and in 12 patients with COPD. A greater extent of HRCT scan abnormalities was found in COPD than in severe and mild asthmatics. HRCT scan abnormalities correlated with the degree of airway obstruction in COPD and in severe asthma. HRCT scan abnormalities also correlated with the levels of sputum elastase both in COPD and in severe asthma. HRCT scan abnormalities were associated with sputum MMP-9/TIMP-1 ratio in mild asthma, severe asthma and COPD. In conclusion, this study demonstrates that sputum elastase and the metalloproteinase-9/tissue-inhibitor metalloproteinase-1 ratio are associated with the magnitude of high-resolution computed tomography scan abnormalities of the airways in asthma and chronic obstructive pulmonary disease, and suggests that the levels of these markers reflect the extent of structural changes of the airway

Reading Videogames as (authorless) Literature

This article presents the outcomes of research, funded by the Arts and Humanities Research Council in England and informed by work in the fields of new literacy research, gaming studies and the socio-cultural framing of education, for which the videogame L.A. Noire (Rockstar Games, 2011) was studied within the orthodox framing of the English Literature curriculum at A Level (pre-University) and Undergraduate (degree level). There is a plethora of published research into the kinds of literacy practices evident in videogame play, virtual world engagement and related forms of digital reading and writing (Gee, 2003; Juul, 2005; Merchant, Gillen, Marsh and Davies, 2012; Apperley and Walsh, 2012; Bazalgette and Buckingham, 2012) as well as the implications of such for home / school learning (Dowdall, 2006; Jenkins, 2006; Potter, 2012) and for teachers’ own digital lives (Graham, 2012). Such studies have tended to focus on younger children and this research is also distinct from such work in the field in its exploration of the potential for certain kinds of videogame to be understood as 'digital transformations' of conventional ‘schooled’ literature. The outcomes of this project raise implications of such a conception for a further implementation of a ‘reframed’ literacy (Marsh, 2007) within the contemporary curriculum of a traditional and conservative ‘subject’. A mixed methods approach was adopted. Firstly, students contributing to a gamplay blog requiring them to discuss their in-game experience through the ‘language game’ of English Literature, culminating in answering a question constructed with the idioms of the subject’s set text ‘final examination’. Secondly, students taught their teachers to play L.A. Noire, with free choice over the context for this collaboration. Thirdly, participants returned to traditional roles in order to work through a set of study materials provided, designed to reproduce the conventions of the ‘study guide’ for literature education. Interviews were conducted after each phase and the outcomes informed a redrafting of the study materials which are now available online for teachers – this being the ‘practical’ outcome of the research (Berger and McDougall, 2012). In the act of inserting the study of L.A. Noire into the English Literature curriculum as currently framed, this research moves, through a practical ‘implementation’ beyond longstanding debates around narratology and ludology (Frasca, 2003; Juul, 2005) in the field of game studies (Leaning, 2012) through a direct connection to new literacy studies and raises epistemological questions about ‘subject identity’, informed by Bernstein (1996) and Bourdieu (1986) and the implications for digital transformations of texts for both ideas about cultural value in schooled literacy (Kendall and McDougall, 2011) and the politics of ‘expertise’ in pedagogic relations (Ranciere, 2009, Bennett, Kendall and McDougall, 2012a)