Guest Editor's Introduction

Journal of Signal Processing Systems -     

"Good, you identified the suspect": Feedback to eyewitnesses distorts their reports of the witnessing experience.

People viewed a security video and tried to identify the gunman from a photospread. The actual gunman was not in the photospread and all eyewitnesses made false identifications (n = 352). Following the identification, witnesses were given confirming feedback ("Good, you identified the actual suspect"), disconfirming feedback ("Actually, the suspect is number __" ), or no feedback. The manipulations produced strong effects on the witnesses' retrospective reports of (a) their certainty, (b) the quality of view they had, (c) the clarity of their memory, (d) the speed with which they identified the person, and (e) several other measures. Eyewitnesses who were asked about their certainty prior to the feedback manipulation (Experiment 2) were less influenced, but large effects still emerged on some measures. The magnitude of the effect was as strong for those who denied that the feedback influenced them as it was for those who admitted to the influence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cardioprotective effect of probucol in the atherosclerosis-prone JCR:LA-cp rat

The second epidermal growth factor (EGF)-like domain of human coagulation factor VII is a potent inhibitor of the FVIIa/tissue factor complex, the predominant initiator of coagulation in vivo. This domain has now for the first time been cloned and expressed in Escherichia coli as an affinity fusion protein. The fusion protein was secreted into the periplasm of E. coli and purified by affinity chromatography. The purified protein consisted of a fusion protein with the expected molecular weight, and in addition, a significant fraction of oligomers cross-linked by intermolecular disulfide bonds. Despite the presence of oligomers, the purified protein was a potent inhibitor of the extrinsic blood coagulation pathway with an IC50 value of about 20 microM. The biological activity was retained after liberation of the EGF domain by proteolytic cleavage.     

Estimation of particle volume fraction, mass fraction and number density in thermophoretic deposition systems

A method is presented to predict the soot volume fraction in soot-laden gas streams in systems where thermophoresis is the dominant mechanism of particle deposition onto adjoining surfaces. In particular, we considered deposition of silica particles on a circular cylinder in cross-flow to a premix CH₄/O₂ flame, a setup similar to the one used in the outside vapor deposition process used for making optical fibers. Silica particles were produced by introducing SiCl₄ along with the premix gases to the burner and were collected on a cylinder. Heat flux and mass deposition rate measurements on the cylinder were performed and recorded as a function of time. Considering thermophoresis to be the dominant mechanism of particle deposition, a simple theory was developed to establish the relationship between the measured quantities. The theory predicted that the thickness at any given time t was expected to increase linearly with the integral of (integrated from t=0 to t=t), where q^′′(t) is the heat flux. Such a linear relationship was observed for five different reactant flow rates confirming thermophoresis to be the dominant mechanism of particle deposition. Soot volume fraction and soot mass fraction were calculated from the slope of these linear fits and were seen to be in good agreement with the estimates of the soot fraction from light scattering measurements. Based on the light scattering estimates of particle diameter, particle number densities were also estimated.     

Fast-Fourier-domain delay line for in vivo optical coherence tomography with a polygonal scanner

We demonstrate in vivo optical coherence tomography using a Fourier-domain optical delay line constructed with a commercially available polygonal scanner. The 20-faceted polygonal mirror array, capable of scanning at rates up to 15 kHz, is implemented at 4 kHz to acquire 500 x 500 pixel images at 8 frames/s with a signal-to-noise ratio of 80 dB. Features of this delay line include scalability to high repetition rates, 98.6% linearity in group delay over 2 mm, and bandwidth support exceeding 150 nm. Images are obtained in an animal model (Xenopus laevis), and limitations due to phase-delay nonlinearity and polygon asymmetry are discussed.     

Rapid field screening of soils for heavy metals with spark-induced breakdown spectroscopy

Spark-induced breakdown spectroscopy (SIBS) is a recently developed atomic-fluorescene-based analytical technique that is analogous to laser-induced breakdown spectroscopy. SIBS, however, uses an electrical plasma generation method on nonconductive samples instead of a focused laser beam. Here we describe the basic characteristics of SIBS and its application to the field-screening analysis of soil, using a standard addition analytical approach. Detection limits of approximately 25 mg/kg have been seen for lead, chromium, barium, mercury, and cadmium. A variety of soils have been tested, some cocontaminated with organic material and uranium (238U).     

Teachers' stereotypes of Asian, Black, and White students.

This research uses two different measurement operations to examine contemporary stereotypes of Asians, Blacks, and Whites held by an ethnically diverse sample of teachers. Data were drawn from a sample of 188 teachers representing over 160 schools in Southern California. Consistent with previous research, participants endorsed a "model minority" stereotype of Asians with regard to intelligence, academic striving, introversion, and rule compliance. Contrary to expectation, there was substantial congruence in the degree of uniformity and favorableness of the stereotypic traits associated with Blacks and Whites, with participants' revealing both strong positive and negative trait associations. The use of both open-ended and fixed-format measurement strategies revealed some method variation in the assessment of participants racial beliefs, with the open-ended format suggesting more complex and heterogeneous racial representations. Results are discussed in terms of methodological issues in stereotype assessment and implications for reducing the impact of racial biases in psychoeducational evaluations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Action planning in the presence of distracting stimuli: An investigation into the time course of distractor effects.

Humans have a remarkable capability to respond efficiently to a stimulus of interest despite other stimuli competing for neural resources. The current study investigated how the human system copes with distracting stimuli. During each trial, participants viewed 2 sequential stimuli that were each associated with a specific action based on an arbitrary mapping. The 1st stimulus served as a distractor, and the 2nd stimulus required a response (target). When the distractor preceded the target by more than a few hundred milliseconds, response latencies were slower when the 2 stimuli were associated with the same response. The authors propose that this negative compatibility effect stemmed from an inhibitory mechanism that the human system utilizes to prevent the distractor from eliciting an unwanted response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scale Effects of Shallow Foundation Bearing Capacity on Granular Material

Scale effects of shallow foundation bearing capacity on granular materials were investigated to further evaluate the trend of decreasing bearing capacity factor, Nγ, with increasing footing width, B, observed by other researchers. Model-scale square and circular footing tests ranging in width from 0.025 to 0.914?m were performed on two compacted sands at three relative densities. Results of the model-scale footing tests show that the bearing capacity factor, Nγ, is dependent on the absolute width of the footing for both square and circular footings. Although this phenomenon is well known, the current study used a large range of footing sizes tested on well-graded sands to show that the previously reported modifications to the bearing capacity factor, Nγ, using grain-size and reference footing width do not sufficiently account for the scale effect seen in the test results from this study. It also shows that behavior of most model-scale footing tests cannot be directly correlated to the behavior of full-scale tests because of differences in mean stresses experienced beneath footings of varying sizes. The relationship of the initial testing conditions (i.e., void ratio) of the sand beds and mean stress experienced beneath the footing (correlated to footing size) to the critical state line controls footing behavior and, therefore, model-scale tests must be performed at a lower density than a corresponding prototype footing in order to correctly predict behavior. Small footings were shown to have low mean stresses but high Nγ values, which indicates high operative friction angles and may be related to the curvature of the Mohr–Coulomb failure envelope.     

Treating another's actions as one's own: Children's memory of and learning from joint activity.

Children often overestimate their contribution to collaborative activities. Across 2 studies, the authors investigated whether this memory bias supports internalization of the actions of others in the context of joint exchanges. After taking turns with (high collaborative condition; Studies 1 and 2) or working independently of (low collaborative condition; Study 2) an adult experimenter to create a series of novel toys, children's agent memory and reconstruction ability were assessed. Children in the high collaborative condition but not the low collaborative condition systematically overclaimed the actions of their social partner, more frequently reporting having completed steps performed by the experimenter than vice versa. This "I did it" bias was related to learning performance: high collaborative children outperformed low collaborative children both during an immediate reconstruction task and 4 months later, and the strength of the bias predicted children's independent toy-building accuracy. It is argued that the "I did it" bias may emerge as part of a general process of learning from others and is supported by a common framework for representing self-actions and other actions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)