209 research outputs found

    Viral loads in clinical specimens and SARS manifestations.

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    1. A high viral load in nasopharyngeal aspirate (with or without a high viral load in serum) is a useful prognostic indicator of respiratory failure or mortality. The presence of viral RNA in multiple body sites is also indicative of poor prognosis. 2. Early treatment with an effective antiviral agent before day 10 may decrease the peak viral load, and thus ameliorate the clinical symptoms and mortality, and reduce viral shedding and the risk of transmissionpublished_or_final_versio

    Awareness of form-sound correspondence in Chinese children with dyslexia: Preliminary results from event-related potentials and time frequency analyses

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    Developmental dyslexia has usually been characterized as having difficulties learning grapheme-phoneme correspondence and applying the mappings. This study investigates form-sound awareness in Chinese reading-impaired children in terms of regularity, consistency and lexicality effects using event-related potentials (ERP) and time-frequency analysis (TFA). Preliminary data from two Cantonese-speaking male children, one with reading impairment (PR) and one with normal reading performance (CA), performing a character recognition task were collected. ERP results indicated that CA showed a lexicality effect at N400 that was not evident in PR. TFA showed that CA exhibited greater event-related synchronization (ERS) and phase coherence at theta and gamma bands suggesting greater cognitive demand in processing pseudo and irregular characters. An opposite pattern was observed for PR, where greater effort was needed to retrieve information related to real and regular characters whilst failing to respond to pseudo and irregular characters. Greater ERS and phase coherence was also observed for real, pseudo and regular characters at 350-450ms at theta suggesting adequate access to phonological and semantic information for CA compared to PR. Whereas PR showed greater ERS and phase coherence at earlier and later time intervals. These initial findings suggest that PR may have weaker semantic representations and may be less sensitive to the internal structure of characters and its relationship with sounds. © 2011 IEEE.published_or_final_versio

    An ERP study of effects of regularity and consistency in delayed naming and lexicality judgment in a logographic writing system

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    Phonological access is an important component in theories and models of word reading. However, phonological regularity and consistency effects are not clearly separable in alphabetic writing systems. We investigated these effects in Chinese, where the two variables are operationally distinct. In this orthographic system, regularity is defined as the congruence between the pronunciation of a complex character (or phonogram), and that of its phonetic radical, while phonological consistency indexes the proportion of orthographic neighbors that share the same pronunciation as the phonogram. In the current investigation, regularity and consistency were contrasted in an event-related potential (ERP) study using a lexical decision task and a delayed naming task with native Chinese readers. ERP results showed that effects of regularity occurred early after stimulus onset and were long-lasting. Regular characters elicited larger N170, smaller P200, and larger N400 compared to irregular characters. In contrast, significant effects of consistency were only seen at the P200 and consistent characters showed a greater P200 than inconsistent characters. Thus, both the time course and the direction of the effects indicated that regularity and consistency operated under different mechanisms and were distinct constructs. Additionally, both of these phonological effects were only found in the delayed naming task and absent in lexical decision, suggesting that phonological access was non-obligatory for lexical decision. The study demonstrated cross-language variability in how phonological information was accessed from print and how task demands could influence this process.published_or_final_versio

    Distinctive effects of regularity and consistency in orthography-phonology mapping in a logographic writing system: an ERP study

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    Poster Session E - Motor Control, Speech Production, Sensorimotor Integration: no. E23In alphabetic scripts, phonological regularity and consistency of print-to-sound mapping are not clearly separable. In contrast, these variables are operationally distinct in Chinese. About 80% of Chinese characters are phonograms, containing a semantic radical that provides a clue to the meaning of the character and a phonetic radical providing a clue to the pronunciation (e.g. 趾 zi2 ‘toe’ has a semantic radical 足meaning ‘foot’ and a phonetic radical 止 zi2). The orthographyphonology mapping in Chinese can be characterized in terms of regularity defined as the congruence between the pronunciation of a phonogram and that of its phonetic radical, and ...postprin

    Learning to read a logographic writing system as a second language: an ERP study of L2 Chinese proficient readers

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    Poster Session E - Language Development, Plasticity, Multilingualism: no. E33For native readers of alphabetic scripts, learning to read a logographic system such as Chinese is challenging. This is not only because Chinese characters look drastically unlike from words in alphabetic scripts, but also because mappings between orthographic and phonological units in the two systems are different. In this study, we investigated two measures of orthography-phonology mapping-- phonological regularity and consistency--in relatively proficient late-acquired second language (L2) readers of Chinese in lexical decision (LD) and delayed naming (DN) tasks. Most Chinese characters are phonograms, which have a phonetic radical that carries phonological ...postprin

    A survey of knowledge, attitudes and practices towards avian influenza in an adult population of Italy

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    <p>Abstract</p> <p>Background</p> <p>Several public health strategic interventions are required for effective prevention and control of avian influenza (AI) and it is necessary to create a communication plan to keep families adequately informed on how to avoid or reduce exposure. This investigation determined the knowledge, attitudes, and behaviors relating to AI among an adult population in Italy.</p> <p>Methods</p> <p>From December 2005 to February 2006 a random sample of 1020 adults received a questionnaire about socio-demographic characteristics, knowledge of transmission and prevention about AI, attitudes towards AI, behaviors regarding use of preventive measures and food-handling practices, and sources of information about AI.</p> <p>Results</p> <p>A response rate of 67% was achieved. Those in higher socioeconomic classes were more likely to identify the modes of transmission and the animals' vehicles for AI. Those older, who knew the modes of transmission and the animals' vehicles for AI, and who still need information, were more likely to know that washing hands soap before and after touching raw poultry meat and using gloves is recommended to avoid spreading of AI through food. The risk of being infected was significantly higher in those from lower socioeconomic classes, if they did not know the definition of AI, if they knew that AI could be transmitted by eating and touching raw eggs and poultry foods, and if they did not need information. Compliance with the hygienic practices during handling of raw poultry meat was more likely in those who perceived to be at higher risk, who knew the hygienic practices, who knew the modes of transmission and the animals' vehicles for AI, and who received information from health professionals and scientific journals.</p> <p>Conclusion</p> <p>Respondents demonstrate no detailed understanding of AI, a greater perceived risk, and a lower compliance with precautions behaviors and health educational strategies are strongly needed.</p

    Processing sublexical phonology in L2 Chinese character reading: An ERP study

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    Poster Session 2: no. ps2p7Compared to alphabetic scripts, the distinct forms of Chinese characters as orthographic units and the fundamental difference in the mappings between orthographic, phonological, and semantic units lead to specific demands in L2 Chinese processing. The current study examined the sensitivity to and time course of two measures of orthography-phonology mapping-- phonological regularity and consistency-- for relatively proficient L2 readers of Chinese. Most Chinese characters are phonograms, which have a phonetic radical that carries phonological information. Regularity in these phonograms is defined by the congruence between the pronunciation of a phonogram and that of its phonetic radical. Consistency is the extent to which the pronunciation of the phonogram is shared by other …postprin

    Cardiovascular sequalae in uncomplicated COVID-19 survivors

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    BACKGROUND: A high proportion of COVID-19 patients were reported to have cardiac involvements. Data pertaining to cardiac sequalae is of urgent importance to define subsequent cardiac surveillance. METHODS: We performed a systematic cardiac screening for 97 consecutive COVID-19 survivors including electrocardiogram (ECG), echocardiography, serum troponin and NT-proBNP assay 1-4 weeks after hospital discharge. Treadmill exercise test and cardiac magnetic resonance imaging (CMR) were performed according to initial screening results. RESULTS: The mean age was 46.5 ± 18.6 years; 53.6% were men. All were classified with non-severe disease without overt cardiac manifestations and did not require intensive care. Median hospitalization stay was 17 days and median duration from discharge to screening was 11 days. Cardiac abnormalities were detected in 42.3% including sinus bradycardia (29.9%), newly detected T-wave abnormality (8.2%), elevated troponin level (6.2%), newly detected atrial fibrillation (1.0%), and newly detected left ventricular systolic dysfunction with elevated NT-proBNP level (1.0%). Significant sinus bradycardia with heart rate below 50 bpm was detected in 7.2% COVID-19 survivors, which appeared to be self-limiting and recovered over time. For COVID-19 survivors with persistent elevation of troponin level after discharge or newly detected T wave abnormality, echocardiography and CMR did not reveal any evidence of infarct, myocarditis, or left ventricular systolic dysfunction. CONCLUSION: Cardiac abnormality is common amongst COVID-survivors with mild disease, which is mostly self-limiting. Nonetheless, cardiac surveillance in form of ECG and/or serum biomarkers may be advisable to detect more severe cardiac involvement including atrial fibrillation and left ventricular dysfunction

    Ripple Texturing of Suspended Graphene Atomic Membranes

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    Graphene is the nature's thinnest elastic membrane, with exceptional mechanical and electrical properties. We report the direct observation and creation of one-dimensional (1D) and 2D periodic ripples in suspended graphene sheets, using spontaneously and thermally induced longitudinal strains on patterned substrates, with control over their orientations and wavelengths. We also provide the first measurement of graphene's thermal expansion coefficient, which is anomalously large and negative, ~ -7x10^-6 K^-1 at 300K. Our work enables novel strain-based engineering of graphene devices.Comment: 15 pages, 4 figure

    Transport Spectroscopy of Symmetry-Broken Insulating States in Bilayer Graphene

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    The flat bands in bilayer graphene(BLG) are sensitive to electric fields E\bot directed between the layers, and magnify the electron-electron interaction effects, thus making BLG an attractive platform for new two-dimensional (2D) electron physics[1-5]. Theories[6-16] have suggested the possibility of a variety of interesting broken symmetry states, some characterized by spontaneous mass gaps, when the electron-density is at the carrier neutrality point (CNP). The theoretically proposed gaps[6,7,10] in bilayer graphene are analogous[17,18] to the masses generated by broken symmetries in particle physics and give rise to large momentum-space Berry curvatures[8,19] accompanied by spontaneous quantum Hall effects[7-9]. Though recent experiments[20-23] have provided convincing evidence of strong electronic correlations near the CNP in BLG, the presence of gaps is difficult to establish because of the lack of direct spectroscopic measurements. Here we present transport measurements in ultra-clean double-gated BLG, using source-drain bias as a spectroscopic tool to resolve a gap of ~2 meV at the CNP. The gap can be closed by an electric field E\bot \sim13 mV/nm but increases monotonically with a magnetic field B, with an apparent particle-hole asymmetry above the gap, thus providing the first mapping of the ground states in BLG.Comment: 4 figure
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