Heritability and psychological tests.

Comments on M. B. Jones's (see record 1971-07242-001) article advocating the use of heritability (HER) as a criterion in psychological test construction, pointing out a disadvantage of using HER as a criterion. One cannot maximize the HER of an intelligence test and then use that test to demonstrate that intelligence is inherited. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Buckling analysis with the aska program system

The theoretical and practical considerations involved in extending the very large, general purpose finite element program system ASKA to include linear buckling mode analysis are presented. The main analysis features and their software implementation are discussed in the context of modular processors and data operands. A broader interpretation of buckling load factors and modes in relation to mode superposition is given, and typical applications are presented to illustrate both classical bifurcation buckling analyses and buckling mode superposition response.     

The mechanism of the adsorption of alkyl xanthate species on galena

Oxidation of galena produced thiosulphate and sulphate ions at the mineral surface but flotation activity, using isopropyl xanthate as collector, was found to depend on the concentration of thiosulphate ions at the surface. It is proposed that the thiosulphate ion reacts with di-isopropyl dixanthogen formed by oxidation of xanthate ion in solution. It was demonstrated that these species react in homogeneous solution to give xanthate and xanthogen-thiosulphate ions. The proposed surface reaction may account for the formation of a layer of adsorbed xanthate ions and for the surface redox potential being raised to a value where more xanthate ions can be chemisorbed and where dixanthogen is stable.     

Effects of cuing on recall from categorized word lists.

Explored the retrieval-deficit hypothesis by comparing free-recall under cued and noncued conditions in 2 groups of 36 5- and 8-yr-olds. On a 16-word list containing either 2, 4, or 8 categories, Ss received 2 trials of noncued recall. The 2nd trial was immediately followed by a test for cued recall. A comparison between cued recall performance and noncued recall performance on Trial 2 indicates that the younger children benefited more than the older children from the cuing procedure. For both age groups, there were effects of cuing on both the number of categories recalled and the number of items per category recalled. Clustering was observed at both age-levels but appeared unrelated to recall performance. Some of the results are discussed in connection with a retrieval deficit hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the growth mechanism of single-walled carbon nanotubes by catalytic carbon vapor deposition on supported metal catalysts

A comprehensive kinetic study was performed to throw light on the formation mechanism of single walled carbon nanotubes (SWNTs) in chemical vapor deposition processes. SWNTs were synthesized by catalytic decomposition of methane or ethylene on supported transition metal catalysts. Kinetic curves (the amount of SWNT as a function of time) were obtained as a function of the nature and the preparation of the supported catalysts, temperature, the fluxes of the gases (the reagent hydrocarbon and the carrying gas), and the partial pressure of the hydrocarbon. The final products were characterized by transmission electron microscopy, Raman spectroscopy, chemical analysis, and thermogravimetric measurements. The fundamental factors determining the SWNT formation are discussed in detail, taking into consideration several observations from the literature as well.     

Hydrocarbon decomposition in alumina membrane: an effective way to produce carbon nanotubes bundles

Carbon nanotubes were synthesised within the pores of an alumina membrane. The membrane had 200 nm diameter pores and 60 microm thickness, and ethylene was used as carbon source. Membrane dissolution by HF results in a bundle of parallel open tubes, aligned without macroscopic defects. The external diameter of the tubes is uniform and there is no evidence of any amorphous carbon. Wall thickness control was obtained by varying the reaction time, length by the thickness of alumina membrane, and external tube diameter by the membrane pore size. Scanning (SEM) and transmission (TEM) electron microscopy, atomic force microscopy (AFM), X-ray diffraction, thermogravimetric analysis (TG) and surface area evaluation by nitrogen adsorption were used for the characterization of membrane and nanotubes.     

Device for the reversed-phase separation and on-target deposition of peptides incorporating a hydrophobic sample barrier for matrix-assisted laser desorption/ionization mass spectrometry

The separation of peptide mixtures from proteolytic cleavage is often necessary prior to mass spectrometry (MS) to enhance sensitivity and peptide mapping coverage. When buffers, salts, and other higher abundance peptides/contaminants are present, competition for charge during the electrospray ionization and matrix-assisted laser desorption/ionization (MALDI) processes can lead to ion suppression for the targeted analyte(s). In this note, a simple reversed-phase microcolumn sample separation and deposition device (Sep-Dep) is described. The use of this device improves or renders possible the analysis of complex or contaminated peptide mixtures by MALDI-MS. The method is simple and inexpensive and utilizes single-use low-cost Geloader-type columns packed with reversed-phase material. The device described utilizes an open column, allowing for a gradient or narrow-step gradient to be applied by any solvent delivery system or manually with a pipet. A key feature of the device is a deposition chamber that can be custom-built to hold any MALDI target. The Sep-Dep device is attached directly to an in-house vacuum line and draws solvent from the open-ended LC column. The elution of separated peptides is performed directly onto a target that has been treated with a hydrophobic barrier. This barrier effectively isolates fractions and improves the quality and morphology of the matrix crystals. The method produces efficient separations of proteolytic peptides, significantly reducing signal suppression effects in MALDI.