Indices de perceptibilité et de différenciabilité des timbres vocaliques : la variabilité [e] - [ε] en français

Devant les incertitudes de la discrimination auditive, en particulier pour la perception du « double timbre » des voyelles en français, on a tenté d’établir des critères objectifs à l’aide de l’analyse acoustique. On a établi deux critères d’analyse formantiques : l’indice de perceptibilité (représentant l’écart acoustique entre F1 et F2) et l’indice de différenciabilité (écart entre les indices de perceptibilité de deux timbres différents). Ils ont permis d’établir une échelle des valeurs acoustiques des timbres du E fermé et ouvert en position accentuée, dans l’idiolecte d’un locuteur français.L’étude perceptive a montré que l’indice de perceptibilité joue un rôle essentiel; donc le fait que le spectre vocalique est diffus ou compact — plutôt que la hauteur absolue des formants. Elle montre également que les timbres ont des réalisations acoustiques extrêmement fluctuantes. Cette variabilité acoustique contraste ici avec le système de réalisations phonétiques nettement catégorisé du locuteur examiné.Les indices établis pourraient probablement être appliqués de manière plus efficace et plus nette à la détermination des timbres inaccentués.Due to the uncertainty of aural discrimination, particularly for the perception of the so called "double timbre" of French vowels, an attempt has been made to establish objective criteria, with the help of acoustical analysis. Two criteria of formant analysis were established: the perceptibility index (representing the acoustical difference between F1 and F2) and the distinguishability index (difference between two perceptibility indexes of two different timbres). We used them in order to establish a scale of acoustical values of timbres for open and closed E in stressed position, in a French speaker's idiolect.A perceptual study showed that the perceptibility index plays an important role and is the most relevant factor for the sake of perception, and that the compactness or diffuseness of the acoustical spectrum is more important than the absolute fixed formant height. This study also shows that timbres have extremely variable acoustic actualisations. This acoustic variability is in contrast here with a rather strict system of phonic realizations, sharply categorized in our speaker's speech.The two indexes that we established here could probably be used in a more efficient and evident way to determine the timbres of unstressed vowels

Signature of a three-dimensional photonic band gap observed on silicon inverse woodpile photonic crystals

We have studied the reflectivity of CMOS-compatible three-dimensional silicon inverse woodpile photonic crystals at near-infrared frequencies. Polarization-resolved reflectivity spectra were obtained from two orthogonal crystal surfaces corresponding to 1.88 pi sr solid angle. The spectra reveal broad peaks with high reflectivity up to 67 % that are independent of the spatial position on the crystals. The spectrally overlapping reflectivity peaks for all directions and polarizations form the signature of a broad photonic band gap with a relative bandwidth up to 16 %. This signature is supported with stopgaps in plane wave bandstructure calculations and with the frequency region of the expected band gap.Comment: 9 pages, 5 figure

Challenges to the implementation of fiscal sustainability measures

Purpose: Fiscal sustainability is high on the global political agenda. Yet, implementing the needed performance-orientation throughout public-sector organizations remains problematic. Such implementation seems to run counter to deep-seated social structures. In this paper the aim is to shed light via key change agents' views on these social structures at the management level during the implementation of a performance-based budgeting scheme. Design/methodology/approach: The authors analyzed documentary data and conducted in-depth, semi-structured interviews with key change agents operative within central government ministries in The Netherlands. The data were analyzed using a structurational approach to identify the enablers and barriers to performance-based budgeting implementation. Findings: In total, 29 social enablers and barriers to performance-based budgeting implementation were derived. These were categorized into: Context, Autonomy, Traditional beliefs, Influence on results, and Top management support. Based on these categories five propositions were developed on how social structures enable and constrain performance-based budgeting implementation among public managers. Research limitations/implications: The study was executed in one country in a specific period in time. Although the problems with performance-based budgeting exist over the globe, research is needed to study whether similar social structures enable and impede implementation. Social implications: Policy makers and change agents aiming to improve fiscal sustainability by budgeting reform need to consider the found social structures. Where possible they could strengthen enablers and design specific comprehensive measures to tackle the barriers identified. Originality/value: This paper provides insight and develops knowledge on the social structures that enable and constrain performance-based budgeting, which in turn improves fiscal sustainability

A More Fundamental Plane

We combine strong-lensing masses with SDSS stellar velocity dispersions and HST-ACS effective (half-light) radii for 36 lens galaxies from the Sloan Lens ACS (SLACS) Survey to study the mass dependence of mass-dynamical structure in early-type galaxies. We find that over a 180--390 km/s range in velocity dispersion, structure is independent of lensing mass to within 5%. This result suggests a systematic variation in the total (i.e., luminous plus dark matter) mass-to-light ratio as the origin of the tilt of the fundamental plane (FP) scaling relationship between galaxy size, velocity dispersion, and surface brightness. We construct the FP of the lens sample, which we find to be consistent with the FP of the parent SDSS early-type galaxy population, and present the first observational correlation between mass-to-light ratio and residuals about the FP. Finally, we re-formulate the FP in terms of surface mass density rather than surface brightness. By removing the complexities of stellar-population effects, this mass-plane formulation will facilitate comparison to numerical simulations and possible use as a cosmological distance indicator.Comment: 4+epsilon pages, 1 figure, emulateapj. Revised version accepted for publication in the ApJ Letter

Observation of sub-Bragg diffraction of waves in crystals

We investigate the diffraction conditions and associated formation of stopgaps for waves in crystals with different Bravais lattices. We identify a prominent stopgap in high-symmetry directions that occurs at a frequency below the ubiquitous first-order Bragg condition. This sub-Bragg diffraction condition is demonstrated by reflectance spectroscopy on two-dimensional photonic crystals with a centred rectangular lattice, revealing prominent diffraction peaks for both the sub-Bragg and first-order Bragg condition. These results have implications for wave propagation in 2 of the 5 two-dimensional Bravais lattices and 7 out of 14 three-dimensional Bravais lattices, such as centred rectangular, triangular, hexagonal and body-centred cubic

Cross-talk between signaling pathways leading to defense against pathogens and insects

In nature, plants interact with a wide range of organisms, some of which are harmful (e.g. pathogens, herbivorous insects), while others are beneficial (e.g. growth-promoting rhizobacteria, mycorrhizal fungi, and predatory enemies of herbivores). During the evolutionary arms race between plants and their attackers, primary and secondary immune responses evolved to recognize common or highly specialized features of microbial pathogens (Chisholm et al., 2006), resulting in sophisticated mechanisms of defense