Mandarin Stress Research Articles

Production of English lexical stress by Mandarin speakers: Acoustics and kinematics

This study aims to understand if Mandarin late learners of English can successfully manipulate acoustic and kinematic cues to deliver English stress contrast in production. Mandarin ( N = 8) and English ( N = 8) speakers were recorded producing English trochaic (initial stress) and iambic (final stress) items during a nonword repetition task. Speakers’ jaw movement for the utterances was tracked and analysed. Acoustic and kinematic cues were measured for each syllable, including acoustic duration, fundamental frequency (F0), and intensity, as well as jaw movement duration, displacement, peak velocity, and stiffness. Stress ratios (syllable 1 / syllable 2) were calculated for each cue and compared between groups. Results showed that English and Mandarin speakers had generally comparable performance in differentiating trochaic from iambic patterns, as well as in the degree of between-syllable contrast within each pattern. Between-group differences were only observed in acoustic duration and jaw movement velocity/stiffness. These results suggest that the experience with Mandarin stress contributes to Mandarin speakers’ overall successful production of English stress but also results in nonnative use of some acoustic/kinematic cues.

Fungal endophytes alleviate drought-induced oxidative stress in mandarin (Citrus reticulata L.): Toward regulating the ascorbate–glutathione cycle

Fungal endophytes grow symbiotically inside a diverse array of plants, and improve viability of the hosts in various mutualistic manners. We investigated the effects of inoculating mandarin endophytic fungi, introduced formerly by our group, i.e. Penicillium citrinum, Aurobassium pullunts and Dothideomycetes sp., individually and in combination with each other on the reactive oxygen species (ROS) scavenging and antioxidant functions in plants under drought stress. To do so, mandarin (Citrus reticulata) scions grafted on Bakraii [Citrus reticulata × Citrus limetta] (Mandarin/Bakraii) were subjected to four irrigations interval including 2, 4, 6 and 8 days, in present/absent of the fungal endophytes. The results indicated that drought stress significantly reduced growth, chlorophyll, carotenoid content and chlorophyll fluorescence (Fv/Fm) of the plants lacking endophytes. Combinatory applications with three fungal endophytes (P. citrinum + A. pullunts + Dothideomycetes sp.) significantly improved the above-mentioned parameters under drought stress. H2O2, O2− and lipid peroxidation level were significantly reduced in the plants inoculated with fungal endophytes. Drought stress significantly increased activities of ascorbate peroxidase (APX), superoxide dismutase (SOD) and glutathione reductase (GR) and levels of ascorbate (ASA) and glutathione (GSH) and decreased activities of catalase (CAT), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR). Fungal endophytes inoculated drought stressed seedlings enhanced the above-mentioned indicators as compared to the drought-stressed plants without fungal endophytes, as well as in the ratios of reduced ascorbate/dehydroascorbic acid (AsA/DHA) and reduced glutathione/oxidized glutathione (GSH/GSSG). Overall, fungal endophyte inoculation improved drought tolerance and reduced the accumulation of ROS by increasing their scavenging via improving the redox state of ascorbate and glutathione and promotion of antioxidant enzymes activity.

Morpheme-like prosodic functions

In this paper we address the long-standing issue of how prosodic patterns are linked to meanings. We explore the idea that prosodically realized communicative functions, such as focus and sentence modality, are analogous to lexical morphemes, the smallest sound units that carry meaning. We considered evidence of a four-way similarity between lexical morphemes and prosodic functions. First, similar to lexical morphemes, each prosodic function consists of multiple phonetic components. Second, like segmental phonemes, individual prosodic components are meaningless themselves, but act jointly to mark both intraand inter-functional contrasts. Third, like lexical morphemes, prosodic functions have allomorph-like variants whose occurrences are conditioned by factors like location in sentence and interaction with other prosodic functions. Finally, similar to lexical morphemes, prosodic functions are language-specific and the specificity has likely historical sources. We examined the evidence by a) reviewing existing literature on speech prosody, b) conducting two new experiments on the production of focus and sentence modality in General American English and Mandarin Chinese, and c) training an articulatory-functional model on focus, modality, tone and stress in English and Mandarin, and synthesizing fully-detailed F0 contours with the learned functional targets. Overall, all the evidence examined is in support of the hypothesis. In particular, the consistency between the target parameters obtained from acoustic analysis and computational modeling, and the close match between functionally synthesized and naturally produced F0 contours demonstrate the plausibility of establishing a clear link between function-specific categorical representations and fine-detailed surface prosody.

Ptcorp gene induced by cold stress was identified by proteomic analysis in leaves of Poncirus trifoliata (L.) Raf.

A proteomic approach was employed to investigate the cold stress-responsive proteins in trifoliate orange (Poncirus trifoliata (L.) Raf.), which is a well-known cold tolerant citrus relative and widely used as rootstock in China. Two-year-old potted seedlings were exposed to freezing temperature (-6°C) for 50min (nonlethal) and 80min (lethal), and the total proteins were isolated from leaves of the treated plants. Nine differentially accumulated proteins over 2-fold changes in abundance were identified by two-dimensional gel electrophoresis and mass spectrometry. Among these proteins, a resistance protein induced by the nonlethal cold treatment (protein spot #2 from P. trifoliata) was selected as target sequence for degenerated primer design. By using the designed primers, a PCR product of about 700bp size was amplified from P. trifoliata genomic DNA, which was further cloned and sequenced. A nucleotide sequence of 676bp was obtained and named Ptcorp. Blast retrieval showed that Ptcorp shared 88% homology with an EST of cold acclimated Bluecrop (Vaccinium corymbosum) library (Accession number: CF811080), indicating that Ptcorp had association with cold acclimation. Semiquantitative RT-PCR analysis demonstrated that Ptcorp gene was up-regulated by cold stress which was consistent with the former result of protein expression profile. As the resistance protein (NBS-LRR disease resistance protein family) gene was up-regulated by cold stress in trifoliate orange and satsuma mandarin, it may imply that NBS-LRR genes might be associated with cold resistance in citrus.

Mandarin Stress Detection Using Acoustic, Lexical and Syntactic Features

The stress is important to improve the naturalness,understandability and intelligibility of speech synthesis system and the correct rate of automatic speech recognition system.In this paper,we conduct stress detection by using the acoustic,lexical and syntactic features based on large scale prosodic annotation corpus.Boosting classification and regression tree is utilized to model the acoustic,lexical and syntactic features,which adequately utilizes the property of the current syllable.Conditional random fields(CRFs) are utilized to model the lexical and syntactic features,which adequately utilize the contextual property of the current syllable.The combination of boosting classification and regression tree and conditional random fields achieves better classification effect when compared with boosting classification and regression tree model or conditional random fields.The combined model overcomes the efficiency of boosting classification and regression tree model,and realizes the complementarities with the advantages of boosting classification and regression tree and conditional random fields.The experimental results indicate that the proposed method acquires better classification effect,and achieves 84.82% stress detection accuracy rate on ASCCD.Compared with the previous counterpart work in the same conditions(the same training set and testing set),there are 4.01% and 1.67% improvements respectively in terms of the correct rate.In this paper,we also compare the differences and the similarities between Mandarin stress detection and English pitch accent detection.Based on the feature analysis on the large scale prosodic annotation corporus,we also verify some linguistic conclusions in a different way.

From English pitch accent detection to Mandarin stress detection, where is the difference?

Although English pitch accent detection has been studied extensively, there relatively a few works explore Mandarin stress detection. Moreover, the comparison and analysis between Mandarin stress detection and English pitch accent detection have not been touched for such counterpart tasks. In this paper, we discuss Mandarin stress detection and compare it with English pitch accent detection. The contributions of the paper are two aspects: one is that we use classifier combination method to detect Mandarin stress and English pitch accent by using acoustic, lexical and syntactic evidence. Our proposed method achieves better performance on both the Mandarin prosodic annotation corpus—ASCCD and the English prosodic annotation corpus—Boston University Radio News Corpus (BURNC) when compared with the baseline system. We also verify our proposed method on other prosodic annotation corpus and continuous speech corpus. The other is the feature analysis. Duration, pitch, energy and intensity features are compared for Mandarin stress detection and English pitch accent detection. Based on the analysis of prosodic annotation corpora, we also verify some linguistic conclusions.

Relative duration as a perceptual cue to stress in Mandarin.

Perceptual tests were carried out to examine (1) whether F0 is necessary to perceive stress in Mandarin, and (2) if not, which cue, duration or intensity, is more important. The results indicate that stress can be identified on the basis of duration and intensity alone; duration is a more important cue than intensity. Acoustical analyses of both natural and reiterant speech revealed that both duration and intensity were correlates of stress. There was a ratio of approximately 3:2 between the durations of stressed and unstressed vowels of the same quality, and a difference of nearly 8 dB between their intensities. In addition, segmental changes, such as consonant and vowel reduction, laryngealization, and vowel devoicing, may enhance the perception of the absence of stress.