43 research outputs found

    Assumptions behind grammatical approaches to code-switching: when the blueprint is a red herring

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    Many of the so-called ‘grammars’ of code-switching are based on various underlying assumptions, e.g. that informal speech can be adequately or appropriately described in terms of ‘‘grammar’’; that deep, rather than surface, structures are involved in code-switching; that one ‘language’ is the ‘base’ or ‘matrix’; and that constraints derived from existing data are universal and predictive. We question these assumptions on several grounds. First, ‘grammar’ is arguably distinct from the processes driving speech production. Second, the role of grammar is mediated by the variable, poly-idiolectal repertoires of bilingual speakers. Third, in many instances of CS the notion of a ‘base’ system is either irrelevant, or fails to explain the facts. Fourth, sociolinguistic factors frequently override ‘grammatical’ factors, as evidence from the same language pairs in different settings has shown. No principles proposed to date account for all the facts, and it seems unlikely that ‘grammar’, as conventionally conceived, can provide definitive answers. We conclude that rather than seeking universal, predictive grammatical rules, research on CS should focus on the variability of bilingual grammars

    Aβ efflux impairment and inflammation linked to cerebrovascular accumulation of amyloid-forming amylin secreted from pancreas

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    Impairment of vascular pathways of cerebral β-amyloid (Aβ) elimination contributes to Alzheimer disease (AD). Vascular damage is commonly associated with diabetes. Here we show in human tissues and AD-model rats that bloodborne islet amyloid polypeptide (amylin) secreted from the pancreas perturbs cerebral Aβ clearance. Blood amylin concentrations are higher in AD than in cognitively unaffected persons. Amyloid-forming amylin accumulates in circulating monocytes and co-deposits with Aβ within the brain microvasculature, possibly involving inflammation. In rats, pancreatic expression of amyloid-forming human amylin indeed induces cerebrovascular inflammation and amylin-Aβ co-deposits. LRP1-mediated Aβ transport across the blood-brain barrier and Aβ clearance through interstitial fluid drainage along vascular walls are impaired, as indicated by Aβ deposition in perivascular spaces. At the molecular level, cerebrovascular amylin deposits alter immune and hypoxia-related brain gene expression. These converging data from humans and laboratory animals suggest that altering bloodborne amylin could potentially reduce cerebrovascular amylin deposits and Aβ pathology

    Gram Positive Filamentous Rods Isolated from Gingival Tissue.

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    Gram Positive Filamentous Rods Isolated from Gingival Tissue.

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    Gram Positive Filamentous Rods Isolated from Gingival Tissue.

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    Gram Positive Filamentous Rods Isolated from Gingival Tissue.

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    Gram Positive Filamentous Rods Isolated from Gingival Tissue.

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    Gram Positive Filamentous Rods Isolated from Gingival Tissue.

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    A Study of the Apollo Lunar Surface Experiments Package Management System

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    This analysis of the Apollo Lunar Surface Experiments Package (ALSEP) management system has four objectives: 1. to document in a general way the history of the ALSEP management system (EMS); 2. to document the existing ALSEP EMS; 3. to develop generalized findings and recommendations that could be applicable to future experiments programs; and 4. to study in some detail the communications interface between the ALSEP EMS and the ALSEP Principal Investigator (P.I.).Contract NAS 9-10993Prepared by Winford E. Holland, William Flannery, Melvin M. FriedlanderVolume 2. Description of the ALSEP -- Chronology of Events in ALSEP Management History -- The McDivitt Letters -- An Analysis of the Written Communication Produced by ALSEP Scientists and MSC Engineers/Managers -- Briefing Guide Used in Presentation of Research Findings -- Listing of Documents that Pertain to ALSEP
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