Reexamining the Vocabulary Spurt.

The authors asked whether there is evidence to support the existence of the vocabulary spurt, an increase in the rate of word learning that is thought to occur during the 2nd year of life. Using longitudinal data from 38 children, they modeled the rate of word learning with two functions, one with an inflection point (logistic), which would indicate a spurt, and one without an inflection point (quadratic). Comparing the fits of these two functions using likelihood ratios, they found that just 5 children had a better logistic fit, which indicated that these children underwent a spurt. The implications for theories of cognitive and language development are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Goal and Personality Trait Development in Emerging Adulthood.

The present research examined continuity and change in the importance of major life goals and the relation between change in goals and change in personality traits over the course of college (N = 298). Participants rated the importance of their life goals 6 times over a 4-year period and completed a measure of the Big Five personality traits at the beginning and end of college. Like personality traits, life goals demonstrated high levels of rank-order stability. Unlike personality traits assessed during the same period and in the same sample, the mean importance of most life goals decreased over time. Moreover, each goal domain was marked by significant individual differences in change, and these individual differences were related to changes in personality traits. These findings provide insights into the relatively unstudied question of how life goals change during emerging adulthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Drinking in the pigeon (Columba livia): Topography and spatiotemporal organization.

Analyzed drinking response of 5 male White Carneaux pigeons by means of high-speed cinematography. Like eating, drinking may be subdivided into 3 movement patterns involving the effector systems of the neck, eyelids, and beak. The major topographic difference between the 2 responses involves beak opening (gape). In eating, beak opening begins prior to contact with the food, and the amount of gape is directly proportional to seed size. In drinking, the beak remains almost closed during descent and opens intermittently and with a relatively small gape during water intake. The topography of drinking in the pigeon differs from that of many birds, and these differences reflect a difference in the mechanism of water ingestion. Data in this study confirm previous observations of a general resemblance between certain features of the pigeon's drinking behavior and the topography of water-reinforced key pecks. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personality development across the life span: Longitudinal analyses with a national sample from Germany.

Longitudinal data from a national sample of Germans (N = 20,434) were used to evaluate stability and change in the Big Five personality traits. Participants completed a brief measure of personality twice, 4 years apart. Structural equation modeling techniques were used to establish measurement invariance over time and across age groups. Substantive questions about differential (or rank-order) and mean-level stability and change were then evaluated. Results showed that differential stability was relatively strong among all age groups but that it increased among young adults, peaked in later life, and then declined among the oldest old. Patterns of mean-level change showed that Extraversion and Openness declined over the life span, whereas Agreeableness increased. Mean levels of Conscientiousness increased among young adults and then decreased among older adults. Trajectories for Neuroticism were relatively flat, with slight increases during middle age and a slight decline in late life. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Biomechanical response of the human foot when standing in a natural position while exposed to vertical vibration from 10–200 Hz

Exposure to foot-transmitted vibration (FTV) can lead to pain and numbness in the toes and feet, increased cold sensitivity, blanching in the toes, and joint pain. Prolonged exposure can result in a clinical diagnosis of vibration-induced white foot (VIWFt). Data on the biomechanical response of the feet to FTV is limited; therefore, this study seeks to identify resonant frequencies for different anatomical locations on the human foot, while standing in a natural position. A laser Doppler vibrometer was used to measure vertical (z-axis) vibration on 21 participants at 24 anatomical locations on the right foot during exposure to a sine sweep from 10–200?Hz with a peak vertical velocity of 30?mm/s. The most notable differences in the average peak frequency occur between the toes (range: 99–147?Hz), midfoot (range: 51–84?Hz) and ankle (range: 16–39?Hz).

Practitioner Summary: The biomechanical response of the human foot exposed to foot-transmitted vibration, when standing in a natural position, was measured for 21 participants. The foot does not respond uniformly; the toes, midfoot, and ankle regions need to be considered independently in future development of isolation strategies and protective measures.     

Microstructure,Hardness, and Residual Stress of the Dissimilar Metal Weldments of SA508-309L/308L-304L

A dissimilar metal weldment consisting of SA508-309L-308L-304L is widely used in light-water nuclear reactors. These weldments demonstrate dissimilar susceptibility to stress corrosion cracking that are related to the microstructure, properties, and residual stress. In this work, microstructures, hardness, and the residual stress distribution of the dissimilar metal weldments were investigated, with the correlation of increased hardness in the heat-affected zone (HAZ) to the microstructure. 304L HAZ demonstrated similar grain morphology as the base material, and the increase in hardness was primarily attributed to the increased dislocation density. SA508 HAZ demonstrated a change of grain morphology resulting from the different peak temperatures and cooling rates. The increased hardness in the SA508 HAZ was attributed to the refined grain morphology, higher dislocation density, and higher number density of precipitates. A ~ 20–30-μm-wide martensitic zone formed at the fusion boundary of SA508-309L, where Cr-rich carbide precipitates were observed, with the average size and the number density of 44.1 ± 16.9 nm and 1.5 × 10²¹ m⁻³, respectively. Residual stress results demonstrated the largest tensile stress at 309L butter, indicating its high cracking susceptibility.

     

Modelling the activity of I in the primary coolant of a CANDU reactor

A mathematical treatment has been developed to describe the activity levels of ¹²⁹I as a function of time in the primary heat transport system during constant power operation and for a reactor shutdown situation. The model accounts for a release of fission-product iodine from defective fuel rods and tramp uranium contamination on in-core surfaces. The physical transport constants of the model are derived from a coolant activity analysis of the short-lived radioiodine species. An estimate of 3×10⁻⁹ has been determined for the coolant activity ratio of ¹²⁹I/¹³¹I in a CANDU Nuclear Generating Station (NGS), which is in reasonable agreement with that observed in the primary coolant and for plant test resin columns from pressurized and boiling water reactor plants. The model has been further applied to a CANDU NGS, by fitting it to the observed short-lived iodine and long-lived cesium data, to yield a coolant activity ratio of ∼2×10⁻⁸ for ¹²⁹I/¹³⁷Cs. This ratio can be used to estimate the levels of ¹²⁹I in reactor waste based on a measurement of the activity of ¹³⁷Cs.     

Evaluation of 9-cis retinoic acid for a new remedy of human retinoblastoma

We investigated the effect of two isomers of retinoic acid (RA), all-trans RA and 9-cis RA, on the proliferation of Y79 human retinoblastoma cells. The two isomers inhibited the cell proliferation in a concentration-dependent manner. The IC50 for this inhibition by all-trans RA and 9-cis RA was 1.50 and 0.15 microM, respectively. The inhibitory effect of 9-cis RA on Y79 cell growth was observed within 24 hr, thereafter the cell number was gradually decreased. In contrast, no inhibition by all-trans RA of Y79 cell growth was observed within 24 hr, thereafter the cell number was slightly increased. In these cases, the cell viability at 4 days after the addition of 9-cis RA and all-trans RA was more than 90% and 95%, respectively. These results indicate that the two RA inhibit the proliferation of Y79 human retinoblastoma cells without inducing the cell death and that the effect of 9-cis RA on the inhibition of Y79 cell growth is much greater than that of all-trans RA.     

Stabilization of foams and emulsions by mixtures of surface active food-grade particles and proteins

Surface active biopolymers such as proteins can form films with particularly high interfacial elasticities and viscosities and these molecules are widely exploited as foaming and emulsifying agents in foods. Solid particles of the correct size and wetting characteristics can also be extremely effective stabilizers of foams and emulsions, although the underlying mechanism of stabilization is somewhat different. Relatively little is known about what happens when both surface active polymers and surface active particles are present together. This work presents recent findings on the effects of mixtures of proteins plus novel food-compatible surface active particles. The proteins include caseins and whey proteins. The surface active particles prepared include cellulose + ethyl cellulose complexes, hydrophobically-modified starch granule particles and stable (non-spreading) protein-stabilized oil droplets. Interfacial shear rheology of adsorbed films was measured via a biconical bob apparatus and interfacial dilatational rheology was measured via a Langmuir trough type apparatus. The corresponding stability of bubbles to coalescence and disproportionation was assessed in separate experiments. Stability of oil-in-water emulsions was assessed via measurement of particle size distributions as function of time and visual assessment of the tendency to creaming and oiling off. In general, it is shown that the surface active particles on their own exhibit much lower measures of interfacial elasticity and viscosity than the proteins, but in combination with the proteins they appear to enhance the interfacial viscoelasticity considerably, with concomitant increases in bubble and emulsion droplet stability. There is little evidence of attractive interactions between the particles and the proteins, so a possible explanation of the increased stability is that the proteins increase the accumulation of particles at the interface, giving rise to increased jamming of particles at the interface.