Atomic decomposition and interpolation for Hardy spaces of noncommutative martingales

We prove that atomic decomposition for the Hardy spaces h_1 and H_1 is valid for noncommutative martingales. We also establish that the conditioned Hardy spaces of noncommutative martingales h_p and bmo form interpolation scales with respect to both complex and real interpolations

Sub-Terahertz Monochromatic Transduction with Semiconductor Acoustic Nanodevices

We demonstrate semiconductor superlattices or nanocavities as narrow band acoustic transducers in the sub-terahertz range. Using picosecond ultrasonics experiments in the transmission geometry with pump and probe incident on opposite sides of the thick substrate, phonon generation and detection processes are fully decoupled. Generating with the semiconductor device and probing on the metal, we show that both superlattices and nanocavities generate spectrally narrow wavepackets of coherent phonons with frequencies in the vicinity of the zone center and time durations in the nanosecond range, qualitatively different from picosecond broadband pulses usually involved in picosecond acoustics with metal generators. Generating in the metal and probing on the nanoacoustic device, we furthermore evidence that both nanostructured semiconductor devices may be used as very sensitive and spectrally selective detectors

Sex-chromosome evolution in frogs: What role for sex-antagonistic genes?

Sex-antagonistic (SA) genes are widely considered to be crucial players in the evolution of sex chromosomes, being instrumental in the arrest of recombination and degeneration of Y chromosomes, as well as important drivers of sex-chromosome turnovers. To test such claims, one needs to focus on systems at early stages of differentiation, ideally with a high turnover rate. Here I review recent work on two families of amphibians, Ranidae (true frogs) and Hylidae (tree frogs), to show that results gathered so far from these groups provide no support for a significant role of SA genes in the evolutionary dynamics of their sex chromosomes. The findings support instead a central role for neutral processes and deleterious mutations

The molecular and dusty composition of Betelgeuse's inner circumstellar environment

The study of the atmosphere of red supergiant stars in general and of Betelgeuse (alpha Orionis) in particular is of prime importance to understand dust formation and how mass is lost to the interstellar medium in evolved massive stars. A molecular shell, the MOLsphere (Tsuji, 2000a), in the atmosphere of Betelgeuse has been proposed to account for the near- and mid-infrared spectroscopic observations of Betelgeuse. The goal is to further test this hypothesis and to identify some of the molecules in this MOLsphere. We report on measurements taken with the mid-infrared two-telescope beam combiner of the VLTI, MIDI, operated between 7.5 and 13.5 $\mu$m. The data are compared to a simple geometric model of a photosphere surrounded by a warm absorbing and emitting shell. Physical characteristics of the shell are derived: size, temperature and optical depth. The chemical constituents are determined with an analysis consistent with available infrared spectra and interferometric data. We are able to account for the measured optical depth of the shell in the N band, the ISO-SWS spectrum and K and L band interferometric data with a shell whose inner and outer radii are given by the above range and with the following species: H2O, SiO and Al2O3. These results confirm the MOLsphere model. We bring evidence for more constituents and for the presence of species participating in the formation of dust grains in the atmosphere of the star, i.e. well below the distance at which the dust shell is detected. We believe these results bring key elements to the understanding of mass loss in Betelgeuse and red supergiants in general and bring support to the dust-driven scenario.Comment: 11 pages, 10 figures, accepted for publication in A&

The impact of a brief structured intervention on young offenders masculine identity: a mixed methods study

Masculinity in young men can be considered a dynamic risk factor. There is a call for programs and initiatives that not only engage adolescent boys in masculinity issues but also promote positive constructs of masculinity. The ‘Man-up’ programme is designed to support men and young men to explore the ways in which the concept of masculinity contributes to shaping their individual identity. The aim of this research evaluation was to explore young offenders’ perceptions of the programme and whether the programme contributed to any personal change/development and what core learning they took from the course. The evaluation utilised a mixed-methods programme of research to address these aims. The quantitative results found that there was a pre/post course reduction in ‘toughness’ and increases in self-esteem and risk-taking perceptions. The qualitative results identified 4 superordinate themes ‘reconstruing masculine self’, ‘self-realisation, awareness and reflection’, ‘group dynamics and course relationships’ and ‘unintended consequences’. The course assisted participants in helping to reconstrue aspects of being a man, made them think about the future and allowed for participants to consider their possible and desired selves. However, for some participants, the course appeared to reinforce some traditional stereotypical beliefs. The implications for course and recommendations are unpacked in the report

Competing interactions in artificial spin chains

The low-energy magnetic configurations of artificial frustrated spin chains are investigated using magnetic force microscopy and micromagnetic simulations. Contrary to most studies on two-dimensional artificial spin systems where frustration arises from the lattice geometry, here magnetic frustration originates from competing interactions between neighboring spins. By tuning continuously the strength and sign of these interactions, we show that different magnetic phases can be stabilized. Comparison between our experimental findings and predictions from the one-dimensional Anisotropic Next-Nearest-Neighbor Ising (ANNNI) model reveals that artificial frustrated spin chains have a richer phase diagram than initially expected. Besides the observation of several magnetic orders and the potential extension of this work to highly-degenerated artificial spin chains, our results suggest that the micromagnetic nature of the individual magnetic elements allows observation of metastable spin configurations.Comment: 5 pages, 4 figure

Qu'est-ce qu'une bonne planification pour un enseignant (...en formation) ?

Enseigner ne se réduit pas à réaliser ce qui a été planifié. Toute situation de classe est beaucoup plus complexe que ce qui peut être prévu, même pour un enseignant chevronné. Le risque, en refusant ce constat, est de " forcer le réel " pour conserver son plan et ainsi garder une illusion de maîtrise et/ou de rester aveugle face à certains imprévus. Si ce risque concerne tous les enseignants, il semble plus problématique dans le cadre de la formation des enseignants