Recognition memory in preschool children.

Tested 18 males and 18 females from each of 2 age groups (mean ages, 37 and 53 mo) on a recognition test under each of 3 conditions: (a) verbal only, (b) visual only, and (c) verbal-visual. Correct recognition was obtained for all Ss. Older Ss, however, performed significantly better than younger. Neither age group benefited from E-provided labels; performance in the visual-only and visual-verbal conditions was comparable. It is concluded that the development of mechanisms other than verbal mediator production must account for any age-related improvement in recognition performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the reproducibility of Tg measurements on polystyrene using d.s.c.

In determining the reproducibility of T_g data of a standard polystyrene measured by differential scanning calorimetry (d.s.c.), the effects of d.s.c. trace interpretation method, extrapolation to zero scan rate, polymer sample form, a thermal treatment and a thermal cycling procedure on the results were examined. The results showed that data from scanning at 8°C/min are preferred to those from extrapolation to zero scan rate while the overall reproducibility was unaffected by the d.s.c. trace interpretation method used. However, the onset of the transition step was selected to define T_g in this work. Similarly, no differences in the reproducibility of data were noted between the overall results for granular or sheet samples, although certain treatments of specific samples did produce changes in some instances. The mean value for T_g at 8°C/min was found to be 102.3°C. Imposing the thermal treatment on the samples did not significantly alter the reproducibility of the results whereas in contrast, cycling markedly improved the reproducibility of sheet sample data but left that of granules unaffected.     

Scanner design

The scanner is a subroutine which is frequently called by an application program like a compiler. The primary function of a scanner is to combine characters from the input stream into recognizable units called tokens. A method has been presented in this paper for designing such a scanner, also frequently referred to as a lexical analyser in the current literature. The major steps involved in this design process are: identification of tokens, construction of a state diagram, building driver tables and finally writing a scanning routine. The rules for generating the driver tables are described and an algorithm for the scanner, utilizing these driver tables, is included. The method has been successfully used to build the system scanner for a user oriented plotting language. It is concluded that the method is well defined, gives rise to a modular design and as such easily lends itself to language extensions.     

Picture cues and exhaustive search facilitate very young children's memory for location.

Conducted 3 experiments to examine the effects of picture cues and exhaustive search on very young children's memory for the location of hidden objects. In Exp I, 64 2-yr-olds' performance was examined with control and exhaustive search procedures in spatial-only and spatial- and picture-cue conditions. In Exp II, 32 2-yr-olds' performance with the same 2 search procedures was examined in a cue condition that eliminated spatial information. In Exp III, 64 2- and 3-yr-olds' performance with the control and exhaustive search procedures was examined in 2 array conditions that also eliminated spatial information. All experiments confirmed that even 2-yr-olds use picture cues to encode and search for the location of hidden objects. It was also found that while 2-yr-olds' delayed response performance was improved by exhaustive search procedures, this was not true for 3-yr-olds. Apparently, more complete search strategies contribute to the developmental change in young children's localization performance. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Standoff detection of high explosive materials at 50 meters in ambient light conditions using a small Raman instrument

We have designed and demonstrated a standoff Raman system for detecting high explosive materials at distances up to 50 meters in ambient light conditions. In the system, light is collected using an 8-in. Schmidt-Cassegrain telescope fiber-coupled to an f/1.8 spectrograph with a gated intensified charge-coupled device (ICCD) detector. A frequency-doubled Nd : YAG (532 nm) pulsed (10 Hz) laser is used as the excitation source for measuring remote spectra of samples containing up to 8% explosive materials. The explosives RDX, TNT, and PETN as well as nitrate- and chlorate-containing materials were used to evaluate the performance of the system with samples placed at distances of 27 and 50 meters. Laser power studies were performed to determine the effects of laser heating and photodegradation on the samples. Raman signal levels were found to increase linearly with increasing laser energy up to approximately 3 x 10(6) W/cm2 for all samples except TNT, which showed some evidence of photo- or thermal degradation at higher laser power densities. Detector gate width studies showed that Raman spectra could be acquired in high levels of ambient light using a 10 microsecond gate width.     

Time-derivative equations for fatigue crack growth in metals

Predicting fatigue crack growth in metals remains a difficult task because available models are based on cycle-derivative equations, such as the Paris law, while service loads are often far from being cyclic. The main objective of this paper is therefore to propose a set of time-derivative equations for fatigue crack growth. The model is based on the thermodynamics of dissipative processes. For this purpose, three global state variables are introduced in order to characterize the state of the crackthe crack length a, the plastic blunting at crack tip and the intensity of crack opening C. Thermodynamics counterparts are introduced for each variable. Special attention is paid to the elastic energy stored inside the crack tip plastic zone, because, in practice, residual stresses at crack tip are known to considerably influence fatigue crack growth. The stored energy is included in the energy balance equation, and this leads to the appearance of a kinematics hardening term in the yield criterion for the cracked structure. No dissipation is associated with crack opening, but to crack growth and to crack tip blunting. Finally, the model consists in two laws: a crack propagation law, which is a relationship between d dt and da/dt and which observes the inequality stemmed from the second principle, and an elastic-plastic constitutive behaviour for the cracked structure, which provides d dt versus applied-load. The model was implemented and tested. It reproduces successfully the main features of fatigue crack growth as reported in the literature, such as the Paris law, the stress-ratio effect and the overload retardation effect.     

Operation Babel: A survey of the effectiveness of the foreign language requirements for the PhD degree in psychology.

681 usable questionnaire returns were received from PhD psychologist respondents. Since completing the language requirements 65% or almost ? of the cases had not read a single item (article or book). "The median number of items read in French, German, Spanish, and Russian was 0." 70% made no oral use of the languages. There is an "extreme incongruity between input and output" in the study of foreign languages at the PhD level. Alternative solutions are proposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spectrophotometric Determination of the Thermodynamic pK Value of Picric Acid in Water at 25 °C

The thermodynamic pK value of picric acid was determined spectrophotometrically in water containing hydrochloric acid to repress the ionization. The pK value 0.33 (K ≈ 0.46) was obtained from data at 450 mμ. Attempts to determine the pK value by potentiometric titrations of picric acid and by spectrophotometric measurements of picric acid solutions in the near-saturation range did not yield satisfactory results. The new pK value is compared with previously published values.     

Polymerization of 2-allyl-1-methylenecyclohexane by the cyclic polymerization mechanism

2-Ally-1-methylenecyclohexane is a compound which is functionally capable of undergoing polymerization by the alternating intra-intermolecular propagation mechanism to produce poly[1,8-methylene[4.3.0] bicyclononane]. This monomer was synthesized and its polymerization through use of cationic and Ziegler-type initiators was studied. Synthesis of the monomer was accomplished by the following reaction sequence: (1) conversion of cyclohexanone to 2-allycyelohexanone by reaction wtih allyl bromide and sodium amide and (2) conversion of 2-allycyclohexanone to the desired monomer by reaction with the phosphorane derived from methyltriphenylphosphonium bromide. Polymerizaton was accomplished by use of boron trifluoride resulting in 44% conversion to polymer, of which 94% was soluble. Through use of infrared and nuclear magnetic resonance techniques, the soluble portion of the polymer was shown to contain 54% of bicyclic units and the remainder to be non-cyelized monomer units in which the residual unsaturation was composed predominantly of allyl groups.     

Thermodynamic Constants for Association of Isomeric Chlorobenzoic and Toluic Acids With 1,3-Diphenyl-guanidine in Benzene

This paper reports values of ΔF₂₅, ΔH, and ΔS₂₅ for the association of diphenylguanidine with the isomeric monochlorobenzoic acids and the isomeric toluic acids in benzene from spectrophotometric measurements at 25 and 30 °C, using bromophthalein magenta E (3′, 5′, 3″, 5″-tetrabromophenolphthalein ethyl ester) as the indicator. The results are compared with available data for other donor-acceptor associations in aprotic solvents which include the monomer-dimer equilibrium of benzoic acids, the association of tertiary amines with iodine, and the association of certain oxygen bases with phenols. The comparisons indicate that the value of the ratio ΔH/298ΔS is approximately constant in the following associations in aprotic solvents: (1) Association of phenolic or carboxylic acids with nitrogenous bases to form hydrogen bonded ion-pairs; (2) hydrogen bonding of weakly acidic phenols to nitrogenous bases; (3) association of tertiary amines with iodine. A somewhat smaller value for this ratio seems to apply to most associations of phenols with oxygen bases. Possible applications of these findings include estimation of other thermodynamic constants when one of the constants ΔF, ΔH, or ΔS is known, and clarification of the relative importance of ionic and covalent contributions in hydrogen bond formation.