A Computational Model for Processing Lexical Information"

The group analysed some syntactic and phonological phenomena that presuppose the existence of interrelated components within the lexicon, which motivate the assumption that there are some sublexicons within the global lexicon of a speaker. This result is confirmed by experimental findings in neurolinguistics. Hungarian speaking agrammatic aphasics were tested in several ways, the results showing that the sublexicon of closed-class lexical items provides a highly automated complex device for processing surface sentence structure. Analysing Hungarian ellipsis data from a semantic-syntactic aspect, the group established that the lexicon is best conceived of being as split into at least two main sublexicons: the store of semantic-syntactic feature bundles and a separate store of sound forms. On this basis they proposed a format for representing open-class lexical items whose meanings are connected via certain semantic relations. They also proposed a new classification of verbs to account for the contribution of the aspectual reading of the sentence depending on the referential type of the argument, and a new account of the syntactic and semantic behaviour of aspectual prefixes. The partitioned sets of lexical items are sublexicons on phonological grounds. These sublexicons differ in terms of phonotactic grammaticality. The degrees of phonotactic grammaticality are tied up with the problem of psychological reality, of how many degrees of this native speakers are sensitive to. The group developed a hierarchical construction network as an extension of the original General Inheritance Network formalism and this framework was then used as a platform for the implementation of the grammar fragments.

A Comparative Study of English Word Order Acquisition by Elementary and Secondary School Pupils - Native Speakers of Serbian and Hungarian

Kitic investigated the phenomenon of English word order acquisition by Serbian and Hungarian speakers, examining both the theoretical and empirical aspects of this phenomenon. She began by looking at language learning and language acquisition, viewing word order acquisition in the context of relevant linguistic and psycholinguistic knowledge. The main hypothesis of her empirical investigation was that the majority of word order mistakes in the language production of Serbian and Hungarian speakers of English is due to mother tongue interference. Three supporting hypotheses were introduced to specify the phenomenon of interference in its correlation to (1) language proficiency, (2) sentence patterns, and (3) optional adverbials. The conclusions were based on error analysis of 9280 sentences of 464 elementary and high school learners. The results showed that a learner's level of proficiency seems to be a relevant factor in mother tongue interference as this decreases with increased proficiency. Word order errors are however fossilised at the highest levels. The causes of interference errors, which increase with the number of sentence elements, are either absent sentence patterns or similar ones. In the case of adverbials, word order errors have two forms: interrelation (with canonical elements) and mixed adverbials.

Duration of methicillin-resistant Staphylococcus aureus carriage, according to risk factors for acquisition

OBJECTIVE: To examine the duration of methicillin-resistant Staphylococcus aureus (MRSA) carriage and its determinants and the influence of eradication regimens. DESIGN: Retrospective cohort study. SETTING: A 1,033-bed tertiary care university hospital in Bern, Switzerland, in which the prevalence of methicillin resistance among S. aureus isolates is less than 5%. PATIENTS: A total of 116 patients with first-time MRSA detection identified at University Hospital Bern between January 1, 2000, and December 31, 2003, were followed up for a mean duration of 16.2 months. RESULTS: Sixty-eight patients (58.6%) cleared colonization, with a median time to clearance of 7.4 months. Independent determinants for shorter carriage duration were the absence of any modifiable risk factor (receipt of antibiotics, use of an indwelling device, or presence of a skin lesion) (hazard ratio [HR], 0.20 [95% confidence interval {CI}, 0.09-0.42]), absence of immunosuppressive therapy (HR, 0.49 [95% CI, 0.23-1.02]), and hemodialysis (HR, 0.08 [95% CI, 0.01-0.66]) at the time MRSA was first MRSA detected and the administration of decolonization regimen in the absence of a modifiable risk factor (HR, 2.22 [95% CI, 1.36-3.64]). Failure of decolonization treatment was associated with the presence of risk factors at the time of treatment (P=.01). Intermittent screenings that were negative for MRSA were frequent (26% of patients), occurred early after first detection of MRSA (median, 31.5 days), and were associated with a lower probability of clearing colonization (HR, 0.34 [95% CI, 0.17-0.67]) and an increased risk of MRSA infection during follow-up. CONCLUSIONS: Risk factors for MRSA acquisition should be carefully assessed in all MRSA carriers and should be included in infection control policies, such as the timing of decolonization treatment, the definition of MRSA clearance, and the decision of when to suspend isolation measures.

Daily organ tracking in intensity-modulated radiotherapy of prostate cancer using an electronic portal imaging device with a dose saving acquisition mode

BACKGROUND AND PURPOSE: Daily use of conventional electronic portal imaging devices (EPID) for organ tracking is limited due to the relatively high dose required for high quality image acquisition. We studied the use of a novel dose saving acquisition mode (RadMode) allowing to take images with one monitor unit per image in prostate cancer patients undergoing intensity-modulated radiotherapy (IMRT) and tracking of implanted fiducial gold markers. PATIENTS AND METHODS: Twenty five patients underwent implantation of three fiducial gold markers prior to the planning CT. Before each treatment of a course of 37 fractions, orthogonal localization images from the antero-posterior and from the lateral direction were acquired. Portal images of both the setup procedure and the five IMRT treatment beams were analyzed. RESULTS: On average, four localization images were needed for a correct patient setup, resulting in four monitor units extra dose per fraction. The mean extra dose delivered to the patient was thereby increased by 1.2%. The procedure was precise enough to reduce the mean displacements prior to treatment to < o =0.3 mm. CONCLUSIONS: The use of a new dose saving acquisition mode enables to perform daily EPID-based prostate tracking with a cumulative extra dose of below 1 Gy. This concept is efficiently used in IMRT-treated patients, where separation of setup beams from treatment beams is mandatory.

Effect of multislice acquisition on T1 and T2 measurements of articular cartilage at 3T

PURPOSE: The aim of this study was to investigate the effect of magnetization transfer on multislice T(1) and T(2) measurements of articular cartilage. MATERIALS AND METHODS: A set of phantoms with different concentrations of collagen and contrast agent (Gd-DTPA(2-)) were used for the in vitro study. A total of 20 healthy knees were used for the in vivo study. T(1) and T(2) measurements were performed using fast-spin-echo inversion-recovery (FSE-IR) sequence and multi-spin-echo (MSE) sequence, respectively, in both in vitro and in vivo studies. We investigated the difference in T(1) and T(2) values between that measured by single-slice acquisition and that measured by multislice acquisition. RESULTS: Regarding T(1) measurement, a large drop of T(1) in all slices and also a large interslice variation in T(1) were observed when multislice acquisition was used. Regarding T(2) measurement, a substantial drop of T(2) in all slices was observed; however, there was no apparent interslice variation when multislice acquisition was used. CONCLUSION: This study demonstrated that the adaptation of multislice acquisition technique for T(1) measurement using FSE-IR methodology is difficult and its use for clinical evaluation is problematic. In contrast, multislice acquisition for T(2) measurement using MSE was clinically applicable if inaccuracies caused by multislice acquisition were taken into account. J. Magn. Reson. Imaging 2007;26:109-117. (c) 2007 Wiley-Liss, Inc.

Introduction of a novel dose saving acquisition mode for the PortalVision aS500 EPID to facilitate on-line patient setup verification

In external beam radiotherapy, electronic portal imaging becomes more and more an indispensable tool for the verification of the patient setup. For the safe clinical introduction of high dose conformal radiotherapy like intensity modulated radiation therapy, on-line patient setup verification is a prerequisite to ensure that the planned dosimetric coverage of the tumor volume is actually realized in the patient. Since the direction of setup fields often deviates from the direction of the treatment beams, extra dose is delivered to the patient during the acquisition of these portal images which may reach clinical relevance. The aim of this work was to develop a new acquisition mode for the PortalVision aS500 electronic portal imaging device from Varian Medical Systems that allows one to take portal images with reduced dose while keeping good image quality. The new acquisition mode, called RadMode, selectively enables and disables beam pulses during image acquisition allowing one to stop wasting valuable dose during the initial acquisition of "reset frames." Images of excellent quality can be taken with 1 MU only. This low dose per image facilitates daily setup verification with considerably reduced extra dose.