Perceiving color across scale: great and small, discrete and continuous

We generalize, to images with continuously varying colors, our previously published model for comparing color differences of spatially discrete visual fields (icons, symbols) of disparate sizes. Our model is structural, including scattering of light by the intraocular media, followed by sparse retinal cone cell sampling of each physiological color primary. We use our model to show that small subtense of less than half a degree drastically reduces the number of discriminable colors available within a color gamut. The proposed generalization predicts and explains appearance of color fields having a wide range of subtenses (from 1/8 deg to 44 deg in examples given).     

Silane‐modified PVC pervaporation membranes for bromoform/water separation

The transport properties of a unique family of silane‐modified poly(vinyl chloride) (PVC) pervaporation membranes for the separation of halogenated hydrocarbons from water were investigated. The PVC was modified by using a vinyl silane to improve its resistance to attack by halogenated hydrocarbons and to increase the flux. Two preparation routes were used: Route i included an initiator to promote the vinyl reaction before the hydrolysis and condensation of the methoxy silane group, whereas Route ni did not. The structures of the membranes were characterized and related to the transport properties, as derived from batch pervaporation experiments. The permeability of unmodified PVC membranes increases with exposure to haloorganics at low concentrations. Initially, the modified membranes exhibited a higher permeability than PVC and a lower selectivity. At long pervaporation times, the silane‐modified membranes exhibited a higher selectivity than PVC. The different preparation routes led to different morphologies, which affected the performance of the membranes; Route ni membranes exhibited higher permeabilities and selectivity than Route i membranes. Rubbery polydimethylsiloxane membranes were resistant to haloorganics but their high water permeability and low selectivity make them unsuitable for this pervaporative separation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1429–1438, 2001     

A process-oriented approach for averting confounds resulting from general performance deficiencies in schizophrenia.

The most pervasive and least well-addressed problem in cognitive studies of schizophrenia is the propensity of schizophrenia patients to show inferior performance on a variety of cognitive tasks. Consequently, apparent specific cognitive abnormalities may actually reflect the interaction of task discriminating power with generalized deficit. L. J. Chapman and J. P. Chapman (1973) suggested psychometric approaches for eliminating such artifactual group differences. Unfortunately, their solution neglects important issues of process specification and does not provide a viable strategy for process-oriented investigators. Psychometric remediation of artifactual Group?×?Task interactions inevitably confounds the processes being measured, resulting in theoretically ambiguous findings. Moreover, evidence that changes in measurement reliability can both increase and decrease group discrimination challenges a basic underlying assumption of the Chapmans' matching solution. This article presents a process-oriented approach to solving this problem in schizophrenia research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantifying repetitive hand activity for epidemiological research on musculoskeletal disorders--part I: individual exposure assessment

An exposure measurement approach is described for quantifying repetitive hand activity of individual workers in a prospective epidemiological study on work-related upper extremity musculoskeletal disorders. A total of 733 subjects were involved in this study at the baseline. Hand activities were quantified by force and repetition. Force levels were measured by workers' self-reports, ergonomists' estimates based on observation and measurements with instrumentation. Repetition levels were measured by detailed time-motion analyses using two repetitive hand activity definitions and ergonomists' estimates using scales for the American Conference of Governmental Industrial Hygienists hand activity level and the Strain Index. Results showed that the present exposure assessment approach seems to be able to quantify force level and repetitiveness of hand activities. Repetitive hand activity is quantified differently depending on whether forceful hand exertion or repetitive muscle activity is used as the definition. These hand activity definitions may quantify different physical exposure phenomena. Individual exposure assessment is important in epidemiological research of musculoskeletal disorders as there are interactions between the individual subjects and the measured parameters. These interactions may vary between exposure parameters.     

Vapor-mediated melt infiltration for synthesizing SiC composite matrices

A two-step synthesis of SiC involving initial exposure of carbon surfaces to Si vapor, followed by Si melt infiltration, is investigated in this article with emphases on the mechanisms, kinetics, and microstructure evolution. Interrupted differential thermal analysis of amorphous C and Si powder mixtures and microstructure characterization are used to generate insight into the stages of the reaction. Exposure to Si vapor yields a SiC layer with nano-scale porosity driven by the volume change associated with the reaction. This forms a continuous pore network that promotes subsequent melt access to the reaction front with the C. While the pores remain open, the vapor phase reaction proceeds at a nearly constant rate and exhibits a strong temperature sensitivity, the latter due in part to the temperature sensitivity of the Si vapor pressure. The implications for enhancing the reactive melt infiltration process and fabrication of SiC matrices for ceramic composites are discussed.     

Test Anxiety and Academic Performance in Undergraduate and Graduate Students.

This study investigated the relationship between test anxiety and academic performance in 4,000 undergraduate and 1,414 graduate students and found a significant but small inverse relationship between test anxiety and grade point average (GPA) in both groups. Low-test-anxious undergraduates averaged a B+, whereas high-test-anxious students averaged a B. Low-test-anxious female graduate students had significantly higher GPAs than high-test-anxious female graduate students, but there were no significant GPA differences between low- and high-test-anxious male graduate students. Female undergraduates had significantly higher test anxiety and higher GPAs than male undergraduates, and female graduate students had significantly higher test anxiety and higher GPAs than male graduate students. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extreme sensitivity of grandisal to acids

Attempted purification of synthetic racemic grandisal1 by silica gel chromatography resulted in severe decomposition. The nature of this reaction was studied on silica gel and in an ether solution ofp-toluenesulfonic acid. The same products resulted from both reaction systems, although in different ratios. Five racemic, rearrangement products were isolated by preparative GC and identified as follows: (1RS, 3SR, 6RS)-1-methyl-5-methylenebicyclo[4.2.0]octan-3-ol (4); (1RS, 3RS, 6RS)-1-methyl-5-methylenebicyclo[4.2.0]octan-3-ol (5); (1RS,3RS,6RS)-1,5-dimethylbicyclo[4.2.0]oct-4-en-3-ol (6); (1RS,3SR,6RS)-1,5-dimethylbicyclo[4.2.0]oct-4-en-3-ol(7); and 3-methyl-7-methylenecyclooct-3-en-l-ol (8). The stereochemical assignments are based on our proposed mechanism, which also accounts for all products observed. The racemic bicyclic enone (3) was a by-product of grandisol (2) oxidation.     

The Multimodal Functional Model--Advancing case formulation beyond the "diagnose and treat" paradigm: Improving outcomes and reducing aggression and the use of control procedures in psychiatric care.

Improving clinical outcomes, treating aggression, and reducing the use of restraints and seclusion are major concerns to providers of psychiatric services. Devising precise treatments directed by causal hypotheses that address the functional properties of maladaptive behaviors are essential for reducing aggression, increasing understanding of causal factors, and enhancing individual control and adaptive choices. This article describes the Multimodal Functional Model (MFM), a sophisticated case formulation and treatment model that moves beyond the "diagnose and treat" paradigm and provides interventions that address causal factors, reduce aggression, and prevent the use of restraints and seclusion in psychiatric settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Grandparents' psychological well-being after loss of contact with their grandchildren.

This study examined how loss of contact with grandchildren due to parental separation or divorce, family feud, or a sudden event, such as relocation, affected the emotional well-being of grandparents (N = 442). Using data from the Longitudinal Study of Generations, the depressive symptoms of grandparents were tracked over 15 years. Growth curve analysis was used to compare grandparents who had lost contact with their grandchildren with those who had not and to examine preloss to postloss change in depressive symptoms. Grandparents who lost contact with their grandchildren experienced a steeper increase in depressive symptoms as they aged compared with other grandparents. Depressive symptoms of grandparents who lost contact because of a sudden event increased up to 3 years following the loss but returned to equilibrium thereafter. The authors conclude that grandparents who lost contact with their grandchildren experienced a negative impact on their emotional health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)