The interaction of children's attribution and level of control over error correction in reading instruction.

32 learning disabled and slowly developing readers were assigned to reading instruction programs on context cue use differing only in extent of pupil control over determination of errors. Results indicate no main effect for experimental condition. However, a significant interaction was found between pretreatment Locus of Attribution (Intellectual Achievement Responsibility Scale) and Experimental Condition. Ss high in internal control benefited more under a condition in which they were encouraged to determine the correctness of their responses. Conversely, Ss low in internality benefited more from a condition in which the teacher determined the correctness of their responses. The results suggest that individual differences in locus of attribution may be important determinants of the extent to which learning-disabled and slow readers benefit from different approaches to reading instruction. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The aging behavior of orthorhombic marten site in Ti-6-2-4-6

In Ti-6-2-4-6 alloys, beta transforms to orthorhombic martensite when quenched from a temperature of 1188 or above, X-ray analysis showed that aging at 773 or 873 gradually reduces the degree of orthorhombicity until a hexagonal structure equivalent to alpha, but having the morphological characteristics of the prior martensite, is produced. The orthorhombicity is reduced by solute rejection to beta which forms as particles both homogeneously and heterogeneously within the martensitic structure. The structure at maximum hardness is a fine distribution of Burger’s oriented beta particles in a matrix of martensite of greatly reduced orthorhombicity. Overaging appears to occur as a result of coarsening of the homogeneous beta particles. It is shown that aging at temperatures from 873 to 1083 K results in growth of one particular varient of the beta which is located at the interface between twin related regions composing a martensite lath. This beta along with similarly oriented beta at lath interfaces forms a continuous beta matrix by a gradual growth process. It is shown that this matrix has the identical orientation and shape of the original beta grain prior to quenching. A mechanism is proposed to account for this “memory effect”.     

A two-front leach model for cement-stabilized heavy metal waste

Quantitative scanning electron microscope (SEM) studies of cement-stabilized waste specimens exposed to a leaching solution at constant pH in the range 4-7 have shown that the acid neutralization capacity (ANC) of the waste matrix is consumed at two consecutive leaching fronts. The first front is associated with the dissolution of portlandite (Ca(OH)2) and the partial reaction of calcium silicate hydrate (CSH) gel. The second front marks the dissolution of Ca-Al hydroxy sulfate minerals. The advancement of the first front is limited by the diffusion of OH- ions from the first front toward the leaching solution. The advancement of the second front, however, is controlled by the diffusion of H+ ions from the leaching solution toward the second front. Leaching of copper, zinc, and lead only occurs between the second front and the specimen surface. The leaching behavior of metals is modeled by considering that metals are leached from the waste matrix as a result of the advancement of the second front. The proposed model takes into account the leachable metal fraction in the waste matrix and the effect of metal remineralization on metal mobility.     

Semiautomated high-throughput extraction and cleanup method for the measurement of polybrominated diphenyl ethers and polybrominated and polychlorinated biphenyls in breast milk

A semiautomated extraction and cleanup method has been developed to measure eight polybrominated diphenyl ethers (PBDEs), 2,2',4,4',5,5'-hexabromobiphenyl (BB-153), and 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153). The method employs solid-phase dispersion on diatomaceous earth in a solid-phase extraction cartridge followed by automated addition of internal standards ((13)C-labeled). Extraction is then performed using an automated modular solid-phase extraction system. The extraction procedure includes drying the sample on diatomaceous earth by pressurized nitrogen and eluting target analytes and lipids with dichloromethane. Lipid content is determined gravimetrically. Lipid determinations performed using this method are compared with other standard methods and with a certified reference material. A relative standard deviation of 7.9% was obtained for 130 determinations of the lipid content in a breast milk quality control sample. Final analytical determination of target analytes was performed by gas chromatography-isotope dilution high-resolution mass spectrometry. Relative standard deviations for the measurements of target analytes for which a labeled internal standard was available were below 10% for analytes at concentrations above 1 ng/g of lipid. Mean recoveries of the (13)C-labeled internal standards ranged from 60 to 89% for the eight PBDE congeners; 74 and 113% were recovered for BB-153 and CB-153, respectively.     

Intraclass correlation vs. factor analytic techniques for determining groups of profiles.

This study compares several methods for estimating the homogeneity of a group and the proper membership of individuals in the group from profile data. A total of 12 MMPI scales were administered to Ss diagnosed in 3 clinical groups and serve as the basic data. Generally the results indicate that the product moment rs and the coefficients of intraclass correlation (R) provide more efficient, flexible and at least as meaningful answers to the basic issues involved in the study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Errors in intelligence estimation with short forms of the WAIS.

Because the full Wechsler Adult Intelligence Scale (WAIS) generally takes more than an hour of the clinician's time to administer, short forms based on a selection of subscales are often substituted. The present study shows that in many cases such short forms may give seriously inaccurate results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Leaching of vanadium and other metals from Athabasca Oil Sands coke and coke ash

Flexicoker coke derived from Athabasca Oil Sands bitumen contains a number of heavy metals, including vanadium, nickel, iron and titanium, which are susceptible to extraction by hydrometallurgical procedures. The leaching behaviour has been studied as a function of pH, temperature and the presence of salts and redox agents. Greater than 50% extraction of the vanadium, iron and nickel can be achieved by acid leaches, but only about 20% of the titanium can be extracted. Weakly acidic leaches extract about 30% of the nickel content but no significant amounts of the other metals. If cokes derived from Athabasca Oil Sands bitumen by the flexicoking process or the conventional delayed-coker coking process are combusted at temperatures below 500 °C, the vanadium and nickel values in the residual ash are readily susceptible to acid leaching.     

Effects of atmospheric ozone on microarray data quality

A data anomaly was observed that affected the uniformity and reproducibility of fluorescent signal across DNA microarrays. Results from experimental sets designed to identify potential causes (from microarray production to array scanning) indicated that the anomaly was linked to a batch process; further work allowed us to localize the effect to the posthybridization array stringency washes. Ozone levels were monitored and highly correlated with the batch effect. Controlled exposures of microarrays to ozone confirmed this factor as the root cause, and we present data that show susceptibility of a class of cyanine dyes (e.g., Cy5, Alexa 647) to ozone levels as low as 5-10 ppb for periods as short as 10-30 s. Other cyanine dyes (e.g., Cy3, Alexa 555) were not significantly affected until higher ozone levels (> 100 ppb). To address this environmental effect, laboratory ozone levels should be kept below 2 ppb (e.g., with filters in HVAC) to achieve high quality microarray data.     

Gender identity and adjustment in black, Hispanic, and white preadolescents.

The generality of S. K. Egan and D. G. Perry's (2001) model of gender identity and adjustment was evaluated by examining associations between gender identity (felt gender typicality, felt gender contentedness, and felt pressure for gender conformity) and social adjustment in 863 White, Black, and Hispanic 5th graders (mean age = 11.1 years). Relations between gender identity and adjustment varied across ethnic/racial groups, indicating that S. K. Egan and D. G. Perry's model requires amendment. It is suggested that the implications of gender identity for adjustment depend on the particular meanings that a child attaches to gender (e.g., the specific attributes the child regards as desirable for each sex); these meanings may vary across and within ethnic/racial groups. Cross-ethnic/racial investigation can aid theory building by pointing to constructs that are neglected in research with a single ethnic/racial group but that are crucial components of basic developmental processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intrinsically Safe Systems?Trends in Design and Installation Standards

Intrinsic safety is a mature proven method to achieve a safe installation of electrical apparatus in a location made hazardous by the presence of flammable or combustible materials. Standards for intrinsically safe apparatus are still evolving. Underwriters' Laboratories, Inc. Standard 913-1975 and NFPA 493-1975 are the most c?omplete statement of requirements for intrinsically safe apparatus and systems yet published. The forthcoming Instrument Society of America Recommended Practice on installation of intrinsically safe systems will fill a pressing need for an installation guide. The National Electrical Code is also changing to recognize the needs of those in the process industries who use intrinsically safe systems and similar apparatus. Much yet needs to be done to define design constraints and Construction requirements for intrinsically safe apparatus. This work is underway.