Gas and vapor sorption in polymers just below Tg

Generally, sorption isotherms for gases like CO₂ in glassy polymers are concave to the pressure axis, whereas in the rubbery state these isotherms are linear for gases or sometimes convex to the pressure axis for more condensable vapors. Examples of CO₂ isotherms are reported here that show at low pressure the curvature characteristic of glasses and then become linear at higher pressures. This is observed when the glass transition temperature T_g is not much greater than the observation temperature T, and plasticization of the polymer by sorbed CO₂ causes T_g to become equal to T within the range of pressures employed in the isotherm measurement. For the sorption of vapors in glassy polymers, this can lead to sigmoidal isotherms, as discussed using an illustration from the literature.     

The interfacial tension between aluminum and cryolite melts saturated with alumina

A Method was developed for measuring the capillary depression of Met.allic aluminum in an alumina tube in a cryolite melt. As the tube was progressively lowered through the melt into the Met.al the volume of gas expelled was measured by the movement of a meniscus of liquid in a horizontal glass tube. No movement occurred after the tube entered the aluminum until it was far enough down that the Met.al could enter it. A correction was applied for the finite radius of the crucible holding the melt, the necessary theory being derived. The contact angle between Met.al, alumina, and cryolite was determined from the shape of the Met.al frozen in the crucible. It was found that the contact angle of the Metal on alumina is very close to 180 deg, and that the interfacial tension at 1000°C is 460 ± 27 mN · m^-1 (standard deviation). Interfacial tension decreases with increasing NaF/AlF₃ ratio, and increases with addition of MgF₂ or Li₃AlF₆. CaF₂ has no significant effect. The hypothesis is advanced that the effect of ratio is due to adsorption of Na atoms, generated by the reaction 3 NaF + Al ⇌ A1F₃ + 3Na, at the interface. Application of the Gibbs adsorption isotherm suggests that at molar ratios NaF/AlF₃ above 2.8 the interface is covered with a monolayer of sodium atoms.     

Performance of process schizophrenics on tasks involving visual search.

Compared the response times of 32 process schizophrenics and 16 nonhospitalized matched controls on 3 visual search tasks. Exp I involved the location of a target letter within an array of different background letters. Other experiments required a same–different response. Exp II involved the identification of a single different letter set within the uniform context of a square display formed by up to 40 replicates of another letter. Exp III presented 2 3–6 letter clusters in a single horizontal line. The 2 clusters were identical or had 1 different letter. Word and nonword clusters were used. Paranoid and nonparanoid groups did not differ on any measure. Schizophrenic response times were about 1 sec longer, but measures of rate of increase in response time with number of letters displayed did not generally differ significantly between groups. Schizophrenics tended to make more errors. Experimental manipulations affected the response times and error rates of schizophrenics and controls alike, and to much the same degree. Results suggest that process schizophrenics are not abnormally slow when extracting information from visual displays, and they appear to perform operations and strategies similar to those of normals when doing so. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A note on current teaching and research in the psychology of music in Canada.

Presents a 70-item bibliography of published and unpublished Canadian literature on the psychology of music. Principal areas of research include perception and psychophysics, experimental aesthetics, and music education. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral approaches to the treatment of early infantile autism: A review.

Examines and evaluates behavioral approaches to the treatment of early infantile autism. Attempts to modify such diverse targets as self-destructive behavior, tantrums, aggressive and disruptive behavior, self-stimulation, toilet training, eye contact, imitation, verbal skills, prosocial behavior, and classroom activity are presented. Issues including proper diagnosis, etiology, and generalization are discussed. It is concluded that although the level of product has been generally less than experimental (or quasi-experimental) in nature, there is reason to believe that behavioral intervention has been associated with real behavior change. (91 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The politics of clinical judgment: Early empirical returns.

Reviews research pertinent to charges that clinicians' judgments are biased against minority and counternormative persons. Evaluative prejudice is found to be a more circumscribed phenomenon than critics of the mental health establishment have forecast. Clinical analogues in which patient race, sex, and value attributions were systematically varied have generally yielded null or marginally supportive results. Social-class designation has been more consistently found to affect psychological appraisals, but even here the drawing of a bias inference is precluded by the rival interpretation of effective environmental-cue utilization by clinicians. Evidence that practitioner political values or experience moderate patient labeling effects has likewise proved unconvincing. Methodological strategies are suggested for strengthening empirical tests of political bias formulations per se by reducing the logical compellingness of the expectancy-cue utilization explanation for any patient attribution effects obtained. (2? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An adaptive typological approach to psychiatric screening.

Tested the feasibility of an adaptive typological approach to psychiatric screening using 9 MMPI code types as prototypal of more comprehensive systems of differential diagnosis. Ss were 1,350 White adult psychiatric outpatients (over 18 yrs of age) whose intake MMPIs fell within 1 of the 9 selected code types. Each code type was represented by 100 Ss in the developmental sample and 50 Ss in the cross-validational sample. Those 69 items that displayed the highest level of statistical difference in endorsement percentage between 2 and/or among several groups were used as predictor variables in a stepwise multiple discriminant-function analysis. The criterion was code type on the standard form. Results indicate that the percentage of correct classifications (when a case was classified into that code type for which he/she obtained the highest probability) was 61% after 30 items and rose to only 69% after 69 items. A variety of decision rules and cutoff points were applied to the data; all demonstrated (a) the ability to discriminate among the groups after the introduction of only 20–30 items into the stepwise program, and (b) the phenomenon of "diminishing returns" with the introduction of more items. There was a point relatively early in testing (30 items) at which it was possible to eliminate most groups from further consideration and beyond which it was counterproductive to introduce more items if one's aim was a 1st-level molar categorization. Implications for branched adaptive testing are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tobacco use in six economically disadvantaged communities in the Dominican Republic.

The Dominican Republic is a tobacco-growing country, and tobacco control efforts there have been virtually nonexistent. This study provides a first systematic surveillance of tobacco use in six economically disadvantaged Dominican Republic communities (two small urban, two peri-urban, two rural; half were tobacco growing). Approximately 175 households were randomly selected in each community (total N = 1,048), and an adult household member reported on household demographics and resources (e.g., electricity), tobacco use and health conditions of household members, and household policies on tobacco use. Poverty and unemployment were high in all communities, and significant gaps in access to basic resources such as electricity, running water, telephones/cell phones, and secondary education were present. Exposure to tobacco smoke was high, with 38.4% of households reporting at least one tobacco user, and 75.5% allowing smoking in the home. Overall, 22.5% reported using tobacco, with commercial cigarettes (58.0%) or self-rolled cigarettes (20.1%) the most commonly used types. Considerable variability in prevalence and type of use was found across communities. Overall, tobacco use was higher in males, illiterate groups, those aged 45 or older, rural dwellers, and tobacco-growing communities. Based on reported health conditions, tobacco attributable risks, and World Health Organization mortality data, it is estimated that at least 2,254 lives could potentially be saved each year in the Dominican Republic with tobacco cessation. Although it is expected that the reported prevalence of tobacco use and health conditions represent underestimates, these figures provide a starting point for understanding tobacco use and its prevalence in the Dominican Republic.     

Source apportionment of ambient volatile organic compounds in Beijing

The ambient air quality standard for ozone is frequently exceeded in Beijing in summer and autumn. Source apportionments of volatile organic compounds (VOCs), which are precursors of ground-level ozone formation, can be helpful to the further study of tropospheric ozone formation. In this study, ambient concentrations of VOCs were continuously measured with a time resolution of 30 min in August 2005 in Beijing. By using positive matrix factorization (PMF), eight sources for the selected VOC species were extracted. Gasoline-related emissions (the combination of gasoline exhaust and gas vapor), petrochemicals, and liquefied petroleum gas (LPG) contributed 52, 20, and 11%, respectively, to total ambient VOCs. VOC emissions from natural gas (5%), painting (5%), diesel vehicles (3%), and biogenic emissions (2%) were also identified. The gasoline-related, petrochemical, and biogenic sources were estimated to be the major contributors to ozone formation potentials in Beijing.