Nondestructive ion trap mass analysis at high pressure

A method for performing nondestructive ion trap mass analysis at high pressures (>1 mTorr) has been developed using image current measurement with constant dipolar excitation. Instead of monitoring the ion secular motion, a harmonic of the ion motion was used for narrow band image current measurement followed by Fourier Transform. The capability of this technique has been demonstrated with mass analysis using a single measurement at pressures of 10 mTorr or higher. Methods for mixture analysis and tandem mass spectrometry have also been developed for nondestructive mass analysis.     

Application of a mechanistic model of bovine milk protein synthesis to examine the use of isotope labeling methods

Two types of models of bovine milk protein synthesis were used to simulate collection and analysis of data from infusion experiments involving isotope-labeled amino acids (AA). Analytical solutions to a system of ordinary differential equations that describe isotope enrichment curves of each AA pool within the mammary gland were derived and are presented. Numerical solutions from a dynamic mechanistic model suggest that normal experimental procedures can affect the shape of enrichment curves and, therefore, results derived from them. Simulation results suggest that standard methods utilizing in vivo isotope kinetics may be of limited value to characterize the metabolism of the bovine mammary gland, especially AA metabolism and milk protein synthesis and secretion. The results clearly demonstrate the flexibility of such models for the testing of many hypotheses and possible experimental protocols.     

No pain, no gain: The conditions under which upward comparisons lead to better performance.

In 3 studies, the authors explored the relation between threatening upward social comparisons and performance. In an initial study, participants were exposed to comparison targets who either threatened or boosted self-evaluations and then completed a performance task. Participants exposed to the threatening target performed better than those in a control group, whereas those exposed to the nonthreatening target performed worse. In Study 2, self-affirmation prior to comparison with threatening targets eliminated performance improvements. In Study 3, performance improvements were found only when the performance domain was different from the domain of success of the comparison target. These boundary conditions suggest that increases in performance following social comparison arise from individuals' motivations to maintain and repair self-evaluations. Implications for the study of the behavioral consequences of social comparison are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distinguishing stereotype threat from priming effects: On the role of the social self and threat-based concerns.

It has been argued that priming negative stereotypic traits is sufficient to cause stereotype threat. The present research challenges this assumption by highlighting the role of the social self and targets' concerns about confirming a negative group-based stereotype. Specifically, in 3 experiments the authors demonstrate that stereotype threat adversely affects the test performance and threat-based concerns of targets (but not nontargets) because only targets' social self is linked to the negative group stereotype. Trait priming, however, harms the test performance of both targets and nontargets but has no effect on their threat-based concerns because trait priming does not require such a link between the social self and the group stereotype. Moreover, the authors show that merely increasing the accessibility of the social self in nonthreatening situations leads to the underperformance of targets but has no meaningful effect on nontargets' test performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design and performance of a planar star mixer

This paper describes the realization of a hybrid star mixer as a planar circuit. The mixer has a minimum conversion loss of 5 dB and, for a conversion loss of less than 9 dB, spans over 2.2 GHz in IF bandwidth and 8 GHz in RF/LO bandwidth. The mixer employs a novel, planar balun structure, similar to conductor-backed CPW, that is suitable for realization as a monolithic circuit     

The referents of trait inferences: The impact of trait concepts versus actor–trait links on subsequent judgments.

The authors investigated the hypothesis that when trait inferences refer to abstract behavior labels they act as a general interpretation frame and lead to assimilation in subsequent judgments of an ambiguous target, whereas when they refer to a specific actor–trait link they will be used as a scale anchor and lead to contrast. Similar to G. B. Moskowitz and R. J. Roman's (see record 1992-31124-001) study, participants who were instructed to memorize trait-implying sentences showed assimilation, and participants who were instructed to form an impression of the actors in these sentences showed contrast. However, exposure to trait-implying sentences that described actors with real names and were accompanied with photos of the actors resulted in contrast under both memorization and impression instructions (Experiment 1). Furthermore, contrast ensued when trait-implying sentences were accompanied with information that suggested a person attribution, whereas assimilation ensued when that information suggested a situation attribution, independent of processing goals (Experiment 2). These findings are interpreted as support for referent-based explanations of the consequences of trait inferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stagewise cognitive development: An application of catastrophe theory.

Presents an overview of traditional methodological approaches to stagewise cognitive developmental research. These approaches are evaluated and integrated on the basis of catastrophe theory. In particular, catastrophe theory specifies a set of common criteria for testing the discontinuity hypothesis proposed by Piaget. Separate criteria correspond to distinct methods used in cognitive developmental research. Such criteria are, for instance, the detection of spurts in development, bimodality of test scores, and increased variability of responses during transitional periods. When a genuine stage transition is present, these criteria are expected to be satisfied. A revised catastrophe model accommodating these criteria is proposed for the stage transition in cognitive development from the preoperational to the concrete operational stage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suitable algorithms for calculating air renewal rate by pulsating air flow through a single large opening

Building ventilation of an enclosure with a single opening is affected not only by the steady mean effect of air pressures and temperatures around and within the building, but also by the turbulent nature of the wind. To improve understanding of the physical phenomena causing air exchange through a single opening, models to simulate the indoor pressure resulting from fluctuations of the wind-induced outdoor pressure are analysed and experimental requirements for model validation are discussed. The influence of the dimensions of the opening and the volume of the room on the time constant are discussed and the numerical constraints of the non-linear low-pass filter modelling for infiltration are highlighted. In particular the frequency limits for data logging or simulations are dependent on this time constant.

A method is proposed to avoid the oscillation of the simulated indoor pressure for the case of under-sampling which frequently occurs because of the limitation of data acquisition rates. The need for further work on this problem is discussed.