Neurobiological evidence for abstract phonological representations in the mental lexicon during speech recognition

A central issue in speech recognition is how contrastive phonemic information is stored in the mental lexicon. The conventional view assumes that this information is closely related to acoustic properties of speech. Considering that no world is ever pronounced alike twice and that the brain has limited capacities to manage information, an opposing view proposes abstract underspecified representations where not all phonemic features are stored. We examined this propos.al using event-related brain potentials, in particular mismatch negativity (MMN), an automatic change detection response in the brain that is sensitive to language-specific phoneme representations. In the current study, vowel pairs were presented to subjects, reversed as standard and deviant. Models not assuming underspecification predict equal MMNsfor vowel pairs regardless of the reversal. In contrast, enhanced and earlier MMNs were observed for those conditions where the standard is not phonologically underspecified in the mental representation. This provides the first neuro-biological evidence for a featurally underspecified mental lexicon.     

Respiratory and general health impairments of ragpickers in India: a study in Delhi

Objective: This study attempted to assess the respiratory and general health of ragpickers who rummage through the garbage dumps and landfill sites in India to collect and sell recyclable materials for a living. Methods: 98 ragpickers and 60 controls from Delhi, matched for age, sex, and socioeconomic conditions, were examined. Health data were obtained from questionnaire survey, clinical examination, and laboratory investigations. Lung function was evaluated by spirometry. Results: After controlling for smoking as a confounder, respiratory symptoms and lung function decrement were recorded in 94% and 52% of the ragpickers, respectively, compared with 56% and 34% of controls. The ragpickers showed a higher prevalence of low hemoglobin, high circulating eosinophil and monocyte counts, unhealthy gums, frequent diarrhea, and dermatitis, when compared with controls. Their sputum showed an abundance of alveolar macrophages, siderophages and inflammatory cells, and a very high frequency of squamous metaplasia and dysplasia of bronchial epithelial cells, suggesting inflammation and cellular changes in the airways. Conclusion: The ragpickers suffer from a multitude of health problems which seem related to their occupation.     

老年人的疼痛问题

何为"老"?理解衰老的最好办法是将其视为一种从生到死的过度和渐变过程.在人们眼中,一旦到了80岁,身体就会变得很衰弱,易受伤,易残疾.但凡事都有例外,最典型的例子就是著名的黑人领袖纳尔逊.曼德拉,他虽年事已高(88岁),但他的才学、智慧、饱经磨难和乐观豁达都是少有人能及的.     

Polymerase chain reaction in the diagnosis of tuberculosis

OBJECTIVES: To evaluate efficacy of polymerase chain reaction (PCR), using the insertion sequence IS6110 as target for DNA, to detect Mycobacterium tuberculosis in body fluids of children with suspected tuberculosis (TB). SETTING: Hospitalized patients. METHODS: A comparison of PCR on body fluids, Acid Fast Bacilli staining (AFB), mycobacterial culture and clinical features, with special emphasis on central nervous system (CNS) TB was done over 18 month period. A total of 80 children were evaluated, 41 with probable TB disease and 39 controls. Cases were defined by specific clinical criteria. Controls included patients free of clinical TB. PCR was done on the clinical specimens and compared with clinical findings, radiological features, Mantoux (Mx) testing, AFB staining and culture on Lowenstein-Jensen (LJ) medium. RESULTS: Sensitivity of PCR in CSF samples was 100%, in gastric aspirate samples was 20% and in pleural fluid samples was 100%. CONCLUSION: PCR technique may become a valuable diagnostic tool for the diagnosis of tuberculosis in children especially in CNS TB.