Mediated action, narratives of risk-taking, and identity formation in adolescents with a visual impairment

The purpose of this project was to discern the inherent tension present in narratives told by adolescents with a visual impairment as they attempted to make sense of their experiences, specifically those surrounding risk. Mediated action, based on the foundational work of Vygotsky and Bakhtin, was used as both a theoretical and methodological approach; it is the theory that there are two components that constitute any human action: the "agent," or the person who is doing the acting, and the "mediational means" that he or she is using to accomplish the action in question. Tension ensues as neither is able to fully explain human behaviour. Ten adolescents with a visual impairment participated in a narrative interview, revealing numerous counter-narratives surrounding risk-taking, including "experimentation undertaken using good judgment." Participants offered examples of how they engaged, appropriated, resisted and transformed the dominant narratives of disability and adolescence in their identity formation.

Psychocentricity and participant profiles: implications for lexical processing among multilinguals

Lexical processing among bilinguals is often affected by complex patterns of individual experience. In this paper we discuss the psychocentric perspective on language representation and processing, which highlights the centrality of individual experience in psycholinguistic experimentation. We discuss applications to the investigation of lexical processing among multilinguals and explore the advantages of using high-density experiments with multilinguals. High density experiments are designed to co-index measures of lexical perception and production, as well as participant profiles. We discuss the challenges associated with the characterization of participant profiles and present a new data visualization technique, that we term Facial Profiles. This technique is based on Chernoff faces developed over 40 years ago. The Facial Profile technique seeks to overcome some of the challenges associated with the use of Chernoff faces, while maintaining the core insight that recoding multivariate data as facial features can engage the human face recognition system and thus enhance our ability to detect and interpret patterns within multivariate datasets. We demonstrate that Facial Profiles can code participant characteristics in lexical processing studies by recoding variables such as reading ability, speaking ability, and listening ability into iconically-related relative sizes of eye, mouth, and ear, respectively. The balance of ability in bilinguals can be captured by creating composite facial profiles or Janus Facial Profiles. We demonstrate the use of Facial Profiles and Janus Facial Profiles in the characterization of participant effects in the study of lexical perception and production.

The study of ligand binding specificities of the lipid binding proteins : recombinant human a-tocopherol transport protein (a-ttp), supernatant protein factor (spf) and S. cerevisiae Sec 14p for vitamin e (rrr-a-tocopherol) and other hydrophobic ligands.

One of the various functions of proteins in biological systems is the transport of small molecules, for this purpose proteins have naturally evolved special mechanisms to allow both ligand binding and its subsequent release to a target site; a process fundamental to many biological processes. Transport of Vitamin E (a-tocopherol), a lipid soluble antioxidant, to membranes helps in the protection of polyunsaturated fatty acids against peroxidative damage. In this research, the ligand binding characteristics of several members of the CRALTRIO family of lipid binding proteins was examined; the recombinant human a-Tocopherol Transfer Protein (a-TIP), Supernatant Protein Factor (SPF)ffocopherol Associated Protein (TAP), Cellular Retinaldehyde Binding Protein (CRALBP) and the phosphatidylinositol transfer protein from S. cerevisiae Sec 14p. Recombinant Sec 14p was expressed and purified from E. coli for comparison of tocopherol binding to the two other recombinant proteins postulated to traffic a-tocopherol. Competitive binding assays using [3H]-a-tocopherol and Lipidex-l000 resin allowed determination of the dissociation constants ~) of the CRAL-TRIO proteins for a-tocopherol and - 20 hydrophobic ligands for evaluation of the possible biological relevance of the binding interactions observed. The KIs (nM) for RRR-a-tocopherol are: a-TIP: 25.0, Sec 14p: 373, CRALBP: 528 and SPFffAP: 615. This indicates that all proteins recognize tocopherol but not with the same affinity. Sec 14p bound its native ligand PI with a KI of381 whereas SPFffAP bound PI (216) and y-tocopherol (268) similarly in contrast to the preferential binding ofRRR-a-tocopherol by a-TIP. Efforts to adequately represent biologically active SPFff AP involved investigation of tocopherol binding for several different recombinant proteins derived from different constructs and in the presence of different potential modulators (Ca+2, Mg+2, GTP and GDP); none of these conditions enhanced or inhibited a-tocopherol binding to SPF. This work suggests that only aTTP serves as the physiological mediator of a-tocopherol, yet structural homology between proteins allows common recognition of similar ligand features. In addition, several photo-affmity analogs of a-tocopherol were evaluated for their potential utility in further elucidation of a-TTP function or identification of novel tocopherol binding proteins.

Other-race faces : limitations of expert face recognition /

Adults' expert face recognition is limited to the kinds of faces they encounter on a daily basis (typically upright human faces of the same race). Adults process own-race faces holistically (Le., as a gestalt) and are exquisitely sensitive to small differences among faces in the spacing of features, the shape of individual features and the outline or contour of the face (Maurer, Le Grand, & Mondloch, 2002), however this expertise does not seem to extend to faces from other races. The goal of the current study was to investigate the extent to which the mechanisms that underlie expert face processing of own-race faces extend to other-race faces. Participants from rural Pennsylvania that had minimal exposure to other-race faces were tested on a battery of tasks. They were tested on a memory task, two measures of holistic processing (the composite task and the part/whole task), two measures of spatial and featural processing (the JanelLing task and the scrambledlblurred faces task) and a test of contour processing (JanelLing task) for both own-and other-race faces. No study to date has tested the same participants on all of these tasks. Participants had minimal experience with other-race faces; they had no Chinese family members, friends or had ever traveled to an Asian country. Results from the memory task did not reveal an other-race effect. In the present study, participants also demonstrated holistic processing of both own- and other-race faces on both the composite task and the part/whole task. These findings contradict previous findings that Caucasian adults process own-race faces more holistically than other-race faces. However participants did demonstrate an own-race advantage for processing the spacing among features, consistent with two recent studies that used different manipulations of spacing cues (Hayward et al. 2007; Rhodes et al. 2006). They also demonstrated an other-race effect for the processing of individual features for the Jane/Ling task (a direct measure of featural processing) consistent with previous findings (Rhodes, Hayward, & Winkler, 2006), but not for the scrambled faces task (an indirect measure offeatural processing). There was no own-race advantage for contour processing. Thus, these results lead to the conclusion that individuals may show less sensitivity to the appearance of individual features and the spacing among them in other-race faces, despite processing other-race faces holistically.