Teaching the pronunciation of sentence final and word boundary stops to French learners of English: distracted imitation versus audio-visual explanations.

Studies on stop unrelease in second language acquisition have hitherto focused on the productions of Slavic learners of English (Šimáčková & Podlipský, 2015) and experiments on Polish learners of English; the latter show the tendency to release stops on a more regular basis depending on the type of stop combinations (Rojczyk et al. 2013). In the present study, we aim to test the efficiency of audio-visual explanations as opposed to distracted imitation in pronunciation teaching amongst French learners of English. While unreleased stops are rather frequent in French and English - especially in plosives clusters (Byrd, 1993; Davidson, 2010), unreleased plosives in final positions are less common in French (Van Dommelen, 1983). During phase 1 of the experiment, three groups of 12 native French learners of English (level A1/A2, B1/B2 and C1/C2) were asked to read idiomatic expressions containing both homogeneous and heterogeneous sequences of voiceless stops straddled between words, namely, in sequences like “that cat” [ðæt˺ kæt˺], and stops at the end of sentences like “I told him to speak” [tə spiːk˺]. In the second phase of the experiment, one half in each group was given a different task. The first group heard recorded versions of phase 1 sentences and before reading them out loud, counted up to five in their L1. Stimuli for imitation contained no release in the contexts under scrutiny. The other half had to watch a video explaining the phenomenon of unreleased stops with a production of phase-two expressions propped up by hand gestures. They were then asked to re-read the sentences given in phase 1. Based on these results the current study makes recommendations about what working environment should be prioritized in pronunciation teaching both in class and online (Kröger et al. 2010), and suggests ways to assess students and visually keep track of their progress

Antidiabetic potential of mucilage fraction extracted from Astragalus gyzensis seeds

The objective of the current work is to extract a new mucilage fraction from Astragalus gyzensis Bunge. seeds, which are collected from the El-Oued province (septentrional Algerian Sahara) and evaluated for their antidiabetic potential. The mucilage fraction is obtained using hot water extraction followed by alcoholic precipitation of polysaccharides by cold ethanol (96%). The primary investigation was performed by describing the main structural features of the extract through colorimetric assays, Fourier-transform infrared spectroscopy and thin-layer chromatography analysis using two systems. Biological activity was also monitored by antidiabetic activity by testing the inhibition of α-amylase and α-glucosidase enzymes in vitro. The extraction yield was 20.69%. The chemical composition mainly consisted of 78.60±0.29% carbohydrates, among them 63.92±0.67% neutral sugar, 15.78±0.76% uronic acid, 8.08±0.04% proteins and 2.57±0.05% phenolic compounds. The results obtained by thin-layer chromatography analysis showed the dominance of mannose and galactose. Fourier-transform infrared spectrum showed characteristic bands expected galactomannans. The investigations highlighted the antihyperglycemic effect in a dose-dependent manner by the inhibition of the α-amylase enzyme (IC50=0.8±0.005 mg/mL). These factors make it suitable for the industrial application of dietary supplement fiber made for diabetic individuals. DOI: http://dx.doi.org/10.5281/zenodo.761853

Méthode numérique pour la résolution de l'écoulement d'un fluide viscoélastique en conduite à paroi déformable

The purpose of this paper is to investigate the flow of a viscoelastic fluid in a distensible tube. The mass conservation equation and the integral momentum one are resolved by using a numerical method analogous to the iterative Buthaud's analysis. A detailled analysis of the influence of the relaxation time on the characteristics of the flow is presented and an application to blood flow in aorta is shown.On présente dans cette étude une simulation numérique de l'écoulement sanguin dans un modèle de l'artère aorte où le sang est considéré comme un fluide viscoélastique. Les équations de conservation de la masse et de la quantité de mouvement sont résolues par une méthode numérique itérative orignale qui permet notamment d'éviter l'introduction d'hypothèses restrictives sur l'évaluation de la contrainte de cisaillement pariétale et du coefficient de correction du débit de quantité de mouvement. Cette étude nous permet d'analyser l'influence du temps de relaxation du fluide sur les caractéristiques hydrodynamiques de l'écoulement

A Compact Dual-Band CPW-Fed Planar Monopole Antenna for 2.62–2.73 GHz Frequency Band, WiMAX and WLAN Applications

Abstract In this paper, we present a compact and low-profile monopole antenna with a simple structure for the 2.6–2.73 GHz frequency band, the Worldwide Interoperability for Microwave Access (WiMAX) and the Wireless Local Area Network (WLAN) applications. The first configuration of our antenna mainly consists by three radiating elements: inverted L-shaped Stub1, L-shaped Stub2 and a rectangle Stub3. By adjusting the lengths of the three Stubs, three resonant frequencies can be achieved and adjusted separately. Then, the assembled between Stub2 and Stub3 gives the final design of our proposed antenna with a small overall size of 20 mm × 37 mm × 1.56 mm. From the experimental results it is observed that, the antenna prototype has achieved two operating bandwidths (S11≤ -10 dB): the first band from 2.62 to 2.73 GHz (110 MHz) and a second broadband from 3.02 to 7.30 GHz (4280 MHz) which combines WiMAX and WLAN applications. The antenna also exhibits an almost omnidirectional radiation patterns over the operating bands. The parameters which affect the performance of the antenna in terms of its frequency domain characteristics are studied in this paper. The details of the monopole antenna design along with simulated and experimental results are presented and discussed