How visual cues to speech rate influence speech perception

Spoken words are highly variable and therefore listeners interpret speech sounds relative to the surrounding acoustic context, such as the speech rate of a preceding sentence. For instance, a vowel midway between short /ɑ/ and long /a:/ in Dutch is perceived as short /ɑ/ in the context of preceding slow speech, but as long /a:/ if preceded by a fast context. Despite the well-established influence of visual articulatory cues on speech comprehension, it remains unclear whether visual cues to speech rate also influence subsequent spoken word recognition. In two ‘Go Fish’-like experiments, participants were presented with audio-only (auditory speech + fixation cross), visual-only (mute videos of talking head), and audiovisual (speech + videos) context sentences, followed by ambiguous target words containing vowels midway between short /ɑ/ and long /a:/. In Experiment 1, target words were always presented auditorily, without visual articulatory cues. Although the audio-only and audiovisual contexts induced a rate effect (i.e., more long /a:/ responses after fast contexts), the visual-only condition did not. When, in Experiment 2, target words were presented audiovisually, rate effects were observed in all three conditions, including visual-only. This suggests that visual cues to speech rate in a context sentence influence the perception of following visual target cues (e.g., duration of lip aperture), which at an audiovisual integration stage bias participants’ target categorization responses. These findings contribute to a better understanding of how what we see influences what we hear

Hall potentiometer in the ballistic regime

We demonstrate theoretically how a two-dimensional electron gas can be used to probe local potential profiles using the Hall effect. For small magnetic fields, the Hall resistance is inversely proportional to the average potential profile in the Hall cross and is independent of the shape and the position of this profile in the junction. The bend resistance, on the other hand, is much more sensitive on the exact details of the local potential profile in the cross junction.Comment: 3 pages, 4 ps figure

Resistance effects due to magnetic guiding orbits

The Hall and magnetoresistance of a two dimensional electron gas subjected to a magnetic field barrier parallel to the current direction is studied as function of the applied perpendicular magnetic field. The recent experimental results of Nogaret {\em et al.} [Phys. Rev. Lett. {\bf 84}, 2231 (2000)] for the magneto- and Hall resistance are explained using a semi-classical theory based on the Landauer-B\"{u}ttiker formula. The observed positive magnetoresistance peak is explained as due to a competition between a decrease of the number of conducting channels as a result of the growing magnetic field, from the fringe field of the ferromagnetic stripe as it becomes magnetized, and the disappearance of snake orbits and the subsequent appearance of cycloidlike orbits.Comment: 7 pages, 7 figure

Explaining the wage gap: Heckscher-Ohlin, economic geography and services availability

In the debate on globalisation and wage inequality Heckscher-Ohlin, economic geography and services availability theory has featured prominently. However, a neglected mechanism by which globalisation affects labour market outcomes is through the in-creased tradability of producer services. By integrating elements of Heck-scher- Ohlin theory, the economic geography literature and the literature on producer services linkages, we show that the impact of globalisation on the relative wages is a sophisticated combination of the effects that play a key-role in these models. The most important result we find is that the fall in transportation costs of producer services might indeed have caused the sharp increase in wage inequality. (JEL F1, R1)

Measurement of the Proteinase Inhibitors of the Bovine Pancreas by Radioimmunoassay

Bovine pancreas contains two polypeptide trypsin inhibitors that are not homologous and differ in their inhibitory activity towards chymotrypsin, kallikrein, elastase, and other serine proteinases. The Kunitz inhibitor and the Kazal inhibitor are present in approximately equimolar concentrations in bovine pancreatic tissue, yet only the Kazal inhibitor is detectable in the pancreatic juice. The Kazal inhibitor has been named the pancreatic secretory trypsin inhibitor, PSTI because its concentration in the pancreatic juice parallels that of the exocrine secretory proteins. The Kunitz inhibitor is considered the intracellular inhibitor, however, no direct information is available concerning the intracellular localization of these inhibitors in the pancreas. The preparation of /sup 125/I-labeled derivatives of Kazal and Kunitz inhibitors by the lactoperoxidase method and a radioimmunoassay for each inhibitor are described

Ginzburg-Landau theory and effects of pressure on a two-band superconductor : application to MgB2

We present a model of pressure effects of a two-band superconductor based on a Ginzburg-Landau free energy with two order parameters. The parameters of the theory are pressure as well as temperature dependent. New pressure effects emerge as a result of the competition between the two bands. The theory then is applied to MgB2. We identify two possible scenaria regarding the fate of the two $\sigma$ subbands under pressure, depending on whether or not both subbands are above the Fermi energy at ambient pressure. The splitting of the two subbands is probably caused by the E2g distortion. If only one subband is above the Fermi energy at ambient pressure (scenario I), application of pressure diminishes the splitting and it is possible that the lower subband participates in the superconductivity. The corresponding crossover pressure and Gruneisen parameter are estimated. In the second scenario both bands start above the Fermi energy and they move below it, either by pressure or via the substitution of Mg by Al. In both scenaria, the possibility of electronical topological transition is emphasized. Experimental signatures of both scenaria are presented and existing experiments are discussed in the light of the different physical pictures.Comment: 6 pages; supersedes the first part of cond-mat/0204085 due to new experiment

Quantum states in a magnetic anti-dot

We study a new system in which electrons in two dimensions are confined by a non homogeneous magnetic field. The system consists of a heterostructure with on top of it a superconducting disk. We show that in this system electrons can be confined into a dot region. This magnetic anti-dot has the interesting property that the filling of the dot is a discrete function of the magnetic field. The circulating electron current inside and outside the anti-dot can be in opposite direction for certain bound states. And those states exhibit a diamagnetic to paramagnetic transition with increasing magnetic field. The absorption spectrum consists of many peaks, some of which violate Kohn's theorem, and which is due to the coupling of the center of mass motion with the other degrees of freedom.Comment: 6 pages, 12 ps figure