Narrow-band collisional activation technique for ion trap mass spectrometers.

Narrow-bandwidth signals were applied to the end caps of an ion trap mass spectrometer to excite ions during collisional activation. Excitation waveforms were created from a single-frequency component and a random noise component using a multiplier circuit. Tandem and higher order mass spectrometry experiments (MS3) can be performed without optimization of the supplemental frequency applied to the end cap electrodes. The usefulness of this method of ion excitation is demonstrated using singly and multiply protonated peptide ions as well as sodium-cationized carbohydrates.     

Synthesis and structural studies of “branched” 2-linked trisaccharides related to h-type 2 blood group determinants

A series of fucosylated trisaccharides l-Fuc-(1→2)-ß-d-Gal-(1→4)-ß-X-OMe (1-6, X = d-GlcNAc, d-Qui (6-deoxy-Glc), d-Xyl) related to H type 2 blood group determinant have been synthesized both as their α- and ß- L-Fuc anomers together with the component disaccharide starting compounds (7-11). The conformational properties of the trisaccharides together with their parent disaccharides have been investigated by NMR spectroscopy (proton and carbon chemical shifts and proton NOEs) in combination with computer modeling using the Monte Carlo approach and the HSEA force field using the GEGOP program with the main focus on the α-linked fucose series. The series of compounds allow for the investigation of interaction between the sugar units in the—in principle—linear structures, which in practice behave as branched trisaccharides. The interaction between the terminal fucose unit and the unit at the reducing end has been probed by substitution of the bulky CH₂OH group with CH₃ and H substituents, respectively. Compounds with severe steric interactions can be identified by the non-additivity of their carbon chemical shifts and subsequently confirmed by the detailed conformational assessment by NOEs and computer modeling. The most severe contacts arise in the GlcNAc and Qui trisaccharide series, whereas the Xyl-containing trisaccharide derivatives only exhibit weak steric interaction as probed by the NMR parameters.     

The effects of "neighborhood size" in reading and lexical decision.

Assessed the effects of neighborhood size ("N")—the number of words differing from a target word by exactly 1 letter (i.e., "neighbors")—on word identification. In Exps 1 and 2, the frequency of the highest frequency neighbor was equated, and N had opposite effects in lexical decision and reading. In Exp 1, a larger N facilitated lexical decision judgments, whereas in Experiment 2, a larger N had an inhibitory effect on reading sentences that contained the words of Exp 1. Moreover, a significant inhibitory effect in Exp 2 that was due to a larger N appeared on gaze duration on the target word, and there was no hint of facilitation on the measures of reading that tap the earliest processing of a word. In Exp 3, the number of higher frequency neighbors was equated for the high-N and low-N words, and a larger N caused target words to be skipped significantly more and produced inhibitory effects later in reading, some of which were plausibly due to misidentification of the target word when skipped. Regression analyses indicated that, in reading, increasing the number of higher frequency neighbors had a clear inhibitory effect on word identification and that increasing the number of lower frequency neighbors may have a weak facilitative effect on word identification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Middleware Support for Transparent Client-Side Caching

This paper reflects on existing caching concepts in proxies and stubs of component technologies and lines out their advantages and deficiencies. A new concept is introduced that averts proliferation of component stubs on client side while transparently providing efficient caching of attributes that doesn't require any changes to existing code at all. Common object-oriented design facilities and code generation tools are leveraged to support seamless integration of these caching concepts into the development cycle.     

Global Model for Calculating Room-Temperature Glass Density from the Composition

A large silicate glass density database including 6719 compositions, obtained from SciGlass^© and other published sources, was systematically analyzed for agreement among room-temperature density data reported in the literature in 1030 different studies from various investigators. It was found that the literature data agree very well. Using just 101 of the initial 6719 degrees of freedom, 99.8% of the measured density data variance could be reproduced by an empirical polynomial model. The standard error of the developed model was 0.019 g/cm³.     

Against parafoveal semantic preprocessing during eye fixations in reading.

Investigated 2 reading models, focused attention and semantic preprocessing, in which nonfoveal information plays an important role. A reading experiment was conducted with 24 normally seeing members of a university community. Ss' eye movements were recorded as they read sentences, and a display change occurred before they fixated on a critical target word. In the target word location, 1 of 4 alternative previews was initially presented: the target word itself, a word semantically related to it, an unrelated word, and a nonword visually similar to the target. The various visual processes occurring during the experiment and the retinal regions involved are discussed. Results are inconsistent with the semantic preprocessing but consistent with the focused-attention model of reading. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

RATE OPTIMAL SEMIPARAMETRIC ESTIMATION OF THE MEMORY PARAMETER OF THE GAUSSIAN TIME SERIES WITH LONG-RANGE DEPENDENCE

There exist several estimators of the memory parameter in long- memory time series models with the spectrum specified only locally near zero frequency. In this paper we give an asymptotic lower bound for the minimax risk of any estimator of the memory parameter as a function of the degree of local smoothness of the spectral density at zero. The lower bound allows one to evaluate and compare different estimators by their asymptotic behaviour, and to claim the rate optimality for any estimator attaining the bound. A log-periodogram regression estimator, analysed by Robinson (Log-periodogram regression of time series with long range dependence. Ann. Stat. 23 (1995), 1048--72), is then shown to attain the lower bound, and is thus rate optimal.     

Development and integration of a concurrently executing interactive user interface for the I-STAT protable clinical analyzer: A case study in real-time systems integration

A novel real-time scheduler was developed to implement an interactive user interface for an existing state-of-the-art, hand-held blood analyzer. A software-timer-based scheduler was designed and implemented and guaranteed schedulability analysis performed to ensure that all hard execution deadlines could be met at run time. An execution bandwidth preservation mechanism that increases the robustness and predictability of the scheduler is presented. The paper is a case study that describes the design and development process from a point of view that emphasizes the importance of the systems integration issues that were encountered.