A study of sentence stress production in Mandarin speakers of American English

Acoustic characteristics of American English sentence stress produced by native Mandarin speakers are reported. Fundamental frequency (F0), vowel duration, and vowel intensity in the sentence-level stress produced by 40 Mandarin speakers were compared to those of 40 American English speakers. Results obtained from two methods of stress calculation indicated that Mandarin speakers of American English are able to differentiate stressed and unstressed words according to features of F0, duration, and intensity. Although the group of Mandarin speakers were able to signal stress in their sentence productions, the acoustic characteristics of stress were not identical to the American speakers. Mandarin speakers were found to produce stressed words with a significantly higher F0 and shorter duration compared to the American speakers. The groups also differed in production of unstressed words with Mandarin speakers using a higher F0 and greater intensity compared to American speakers. Although the acoustic differences observed may reflect an interference of L1 Mandarin in the production of L2 American English, the outcome of this study suggests no critical divergence between these speakers in the way they implement American English sentence stress.     

{l_p}-Recovery of the Most Significant Subspace Among Multiple Subspaces with Outliers

We assume data sampled from a mixture of \(d\) -dimensional linear subspaces with spherically symmetric distributions within each subspace and an additional outlier component with spherically symmetric distribution within the ambient space (for simplicity, we may assume that all distributions are uniform on their corresponding unit spheres). We also assume mixture weights for the different components. We say that one of the underlying subspaces of the model is most significant if its mixture weight is higher than the sum of the mixture weights of all other subspaces. We study the recovery of the most significant subspace by minimizing the \(l_p\) -averaged distances of data points from \(d\) -dimensional subspaces of \(\mathbb R^D\) , where \(0 < p \in \mathbb R\) . Unlike other \(l_p\) minimization problems, this minimization is nonconvex for all \(p>0\) and thus requires different methods for its analysis. We show that if \(0 , then for any fraction of outliers, the most significant subspace can be recovered by \(l_p\) minimization with overwhelming probability (which depends on the generating distribution and its parameters). We show that when adding small noise around the underlying subspaces, the most significant subspace can be nearly recovered by \(l_p\) minimization for any \(0 with an error proportional to the noise level. On the other hand, if \(p>1\) and there is more than one underlying subspace, then with overwhelming probability the most significant subspace cannot be recovered or nearly recovered. This last result does not require spherically symmetric outliers.     

Preparation of 1-aminomethylenemercapto derivatives of 2, 4, 6, 8-tetrathiaadamantane and adamantane

1-Aminomethylenemercapto derivatives of 3, 5, 7, 9, 9-pentamethyl-2, 4, 6, 8-tetrathiaadamantane and adamantane were obtained by aminomethylation of 3, 5, 7, 9, 9-pentamethyl-2, 4, 6, 8-tetrathiaadamantane-l-thiol and adamantane-1-thiol.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 658–660, May, 1976.     

Policy and the standards debate: mapping changes in assessment in mathematics

ABSTRACT

The influences on governments for policy changes in schools range across many agencies, including the political party in power. When policies change, the sources of these influences are not always clear. The project whose work is presented in this special issue examines what these changes look like in terms of the differences in assessment tasks of school pupils’ mathematics, over time. In this article we attempt to develop a graph, which we argue will have general applicability internationally, that can help to reveal the sources and nature of those influences. We construct the graph in interaction with an examination of the most recent changes in two countries. We argue that our analysis is a necessary complement to the project’s findings in that it enables us to identify the fields of recontextualisation, their relative strengths in terms of influence and hence conjecture their impact on the mathematics curriculum.     

Spectral biodiagnostics of tissues with fiber optics

The synergy of novel MIR-fibers with FTIR-spectroscopy opens a new horizon in applications of spectroscopy in 4 − 16 μm range in vivo medical diagnostics. The innovated bare core and core-clad MIR-fibers are produced by hot extrusion method from the crystals of silver halides solid solutions. These non-toxic and non-hygroscopic fibers are characterized by low optical losses: 0.1 − 0.5 dB/m nearby 10μm, and high flexibility: R_bending > 10–100 fiber diameters. Some prototypes of accessories for FTIR-spectrometers, based on commercially available MIR-fibers for several areas of promising applications are developed. Non-invasive medical diagnostics in vivo: cancer detection and glucose content measurements in whole human blood is possible. The new family of evanescent fiber sensors is started for the direct in-process applications. Fiberoptic Evanescent Wave FTIR Spectroscopy (FEWS) for cancer diagnosis in human organs is exemplified in this paper, and their great potentiality is demonstrated.     

On solution of problems of dynamics of plates and shells with local structure heterogeneities

A general approach to the solution of nonstationary problems of the theory of shells with local structure heterogeneities is proposed. The approach is based on representation of solutions for the systems of differential motion equations of shell theory in the form of expansions in terms of free forms of vibrations (FFV). Two implementations of the approach, involving FFV expansions of certain members and FFV expansions of the system as a whole, are considered. The capabilities of the approach are illustrated by results for specific problems. In the first implementation, we determine the dynamic stress-strain state of a square plate with three rod supports. A round plate connected to a coaxial circular cylindrical shell is considered as an example of FFV expansion of the system as a whole. Special Design and Engineering Office, S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika, Vol. 35, No. 10, pp. 46–53, October, 1999     

Confidence regions for solutions of applied boundary-value problems

We propose a practicable technique for determining the confidence regions of solutions of partial differential equations when errors are present both in the process of solution and in the process of specification (mathematical modeling) of the applied problem. The study focuses on applied boundary-value problems in the theory of shells. We elucidate the possibilities of determining the degree of confidence (both posterior and prior) of the numerical results depending on the use of various numerical schemes and mathematical models for some particular cases. Graphical and numerical data are presented demonstrating the application of the proposed technique.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 62, pp. 81–90, 1987.