A procedure that processes a corpus of text and produces numeric vectors containing information about its meanings for each word is presented. This procedure is applied to a large corpus of natural language text taken from Usenet, and the resulting vectors are examined to determine what information is contained within them. These vectors provide the coordinates in a high-dimensional space in which word relationships can be analyzed. Analyses of both vector similarity and multidimensional scaling demonstrate that there is significant semantic information carried in the vectors. A comparison of vector similarity with human reaction times in a single-word priming experiment is presented. These vectors provide the basis for a representational model of semantic memory, hyperspace analogue to language (HAL).

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Dissociations between noun and verb processing are not uncommon after brain injury; yet, precise psycholinguistic comparisons of nouns and verbs are hampered by the underrepresentation of verbs in published semantic word norms and by the absence of contemporary estimates for part-of-speech usage, We report herein image ability ratings and rating response times (RTs) for 1,197 words previously categorized as pure nouns, pure verbs, or words of balanced noun-verb usage on the basis of the Francis and Kucera (1982) norms. Nouns and verbs differed in rated imageability, and there was a stronger correspondence between imageability rating and RT for nouns than for verbs. For all word types, the image-rating-RT function implied that subjects employed an image generation process to assign ratings, We also report a new measure of noun-verb typicality that used the Hyperspace Analog to Language (HAL; Lund & Burgess, 1996) context vectors (derived from a large sample of Usenet text) to compute the mean context distance between each word and all of the pure nouns and pure verbs. For a subset of the items, the resulting HAL noun-verb difference score was compared with part-ofspeech usage in a representative sample of the Usenet corpus. It is concluded that this score can be used to estimate the extent to which a given word occurs in typical noun or verb sentence contexts in informal contemporary English discourse. The item statistics given in Appendix B will enable experimenters to select representative examples of nouns and verbs or to compare typical with atypical nouns (or verbs), while holding constant or covarying rated imageability.

Extensively drug-resistant (XDR) tuberculosis (TB) cannot be easily or quickly diagnosed. We developed a rapid, automated assay for the detection of XDR-TB plus resistance to the drug isoniazid (INH) for point-of-care use. Using a simple filter-based cartridge with an integrated sample processing function, the assay identified a wide selection of wild-type and mutant sequences associated with XDR-TB directly from sputum. Four new large-Stokes-shift fluorophores were developed. When these four Stokes-shift fluorophores were combined with six conventional fluorophores, 10-color probe detection in a single PCR tube was enabled. A new three-phase, double-nested PCR approach allowed robust melting temperature analysis with enhanced limits of detection (LODs). Finally, newly designed sloppy molecular beacons identified many different mutations using a small number of probes. The assay correctly distinguished wild-type sequences from 32 commonly occurring mutant sequences tested in gyrA, gyrB, katG, and rrs genes and the promoters of inhA and eis genes responsible for resistance to INH, the fluoroquinolone (FQ) drugs, amikacin (AMK), and kanamycin (KAN). The LOD was 300 CFU of Mycobacterium tuberculosis in 1 ml sputum. The rate of detection of heteroresistance by the assay was equivalent to that by Sanger sequencing. In a blind study of 24 clinical sputum samples, resistance mutations were detected in all targets with 100% sensitivity, with the specificity being 93.7 to 100%. Compared to the results of phenotypic susceptibility testing, the sensitivity of the assay was 75% for FQs and 100% each for INH, AMK, and KAN and the specificity was 100% for INH and FQ and 94% for AMK and KAN. Our approach could enable testing for XDR-TB in point-of-care settings, potentially identifying highly drug-resistant TB more quickly and simply than currently available methods.KEYWORDS 10-color assay, three-phase PCR, XDR-TB, point-of-care test

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