Age differences in reaction time and attention in a national telephone sample of adults: Education, sex, and task complexity matter.

This study demonstrated effects of age, education, and sex on complex reaction time in a large national sample (N = 3,616) with a wide range in age (32-85) and education. Participants completed speeded auditory tasks (from the MIDUS [Midlife in the U.S.] Stop and Go Switch Task) by telephone. Complexity ranged from a simple repeated task to an alternating task that involved central executive processes including attention switching and inhibitory control. Increased complexity was associated with slower responses in older adults, those with lower education, and women, even after controlling for differences in health status. Higher levels of education were associated with greater central executive efficiency across adulthood: Overall, adults with college degrees performed on complex tasks like less educated individuals who were 10 years younger, up to age 75. These findings suggest that advanced education can moderate age differences on complex speeded tasks that require central executive processes, at least up to the point in old age at which biological declines predominate. The approach demonstrates the utility of combining laboratory paradigms with survey methods to enable the study of larger, more diverse and representative samples across the lifespan. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fracture behavior of carbon nanotube/carbon microfiber hybrid polymer composites

Growing carbon nanotubes (CNTs) on the surface of fibers has the potential to modify fiber–matrix interfacial adhesion, enhance composite delamination resistance, and possibly improve toughness. In the present study, aligned CNTs were grown upon carbon fabric via chemical vapor deposition. Continuously monitored single-fiber composite fragmentation tests were performed on pristine and CNT-grafted fibers embedded in epoxy, and single-laminate compact-tension specimens were tested for fracture behavior. A significant increase (up to 20 %) was observed in the interfacial adhesion, at the cost of a decrease in the fiber tensile strength. As a result, the maximum load of the composite was decreased, but its residual load-bearing capacity more than doubled. The likely sources of these effects are discussed, as well as their implications.     

Impact of selected factors – Cultivar,storage, cooking and baking on the content of anthocyanins in coloured-flesh potatoes

The impact of selected factors – cultivar, storage, cooking and baking on the content of total anthocyanins (TAC) in coloured-flesh potato cultivars has been studied. TAC ranged from 248.5 to 2257.8 mg kg⁻¹ dry matter (DM). TAC difference between cultivars was statistically significant. Cold storage (4 °C) influenced TAC differentially. In the Violette and Highland Burgundy Red cultivars TAC increased by 18.5% and 12.1% respectively, and in the Valfi cultivar it decreased by 33.9%. Baking increased TAC 3.34 times whereas cooking in boiled water increased it 4.22 times. Correlation between antioxidant activity (AOA) and TAC (r² = 0.659) has been found. The Violette, Vitelotte and Highland Burgundy Red cultivars with the highest TAC showed high AOA and the Shetland Black cultivar and the cultivars Salad Blue and Blue Congo with a “marbled” texture showed the lowest TAC and AOA. Individual anthocyanidins are fingerprints of colour-fleshed potato cultivars.     

Fluid cognitive ability is associated with greater exposure and smaller reactions to daily stressors.

The authors of this study investigated whether fluid cognitive ability predicts exposure and emotional reactivity to daily stressors. A national sample of adults from the Midlife in the United States study and the National Study of Daily Experiences (N = 1,202) who had a mean age of 57 years (SD = 12; 56% women, 44% men) completed positive and negative mood reports as well as a stressor diary on 8 consecutive evenings via telephone. Participants also completed a telephone-based battery of tests measuring fluid cognitive ability. Higher levels of fluid cognitive ability were associated with greater exposure to work- and home-related overload stressors. Possessing higher levels of fluid cognitive ability was associated with smaller stressor-related increases in negative mood, primarily for interpersonal tensions and network stressors, and smaller stressor-related decreases in positive mood for interpersonal tensions. Furthermore, fluid cognitive ability was unrelated to subjective severity ratings of the stressors reported. Discussion focuses on the role of fluid cognitive ability in daily stress processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived control and intellectual functioning in the elderly: A 5-year longitudinal study.

We examined whether control beliefs are related to individual differences in intellectual aging by administering a battery of intellectual tests and perceived control scales to 63 elderly adults in 1981 and in 1986. Over the 5 years there were no changes in generalized control or intellectual performance, but there were changes in intellectual control beliefs. Specifically, the participants reported an increased dependence on others to carry out cognitive tasks. The cross-occasion stability correlations were relatively high, although there was some evidence for individual differences in change, especially for the control variables. Surprisingly, those with higher levels of education were more likely to show decreases in perceived intellectual control. Health was a significant antecedent of individual changes in vocabulary performance and intellectual control. The results also indicated that fluid intelligence was a significant predictor of changes in intellectual control beliefs, but control beliefs did not affect performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Statistically significant difference or probable nonchance difference.

Comments that the term statistically significant difference, widely and frequently used in research, is misleading. The author explains why statistically significant difference should be replaced with a less misleading and more accurate phrase: probable nonchance difference or probable nonrandom difference. (0 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Locus of control in aging research: A case for multidimensional and domain-specific assessment.

Three studies examined the usefulness of multidimensional and domain-specific measures of locus of control for examining age differences and correlates. 188 college students and 192 60–91 yr olds completed the Levenson Locus of Control Scales; the Multidimensional Health Locus of Control Scale; and the M. E. Lachman et al (see record 1983-23234-001) intellectual locus of control questionnaire. As predicted, no age differences were found with the generalized measures, but the elderly were more external on intelligence- and health-specific locus of control dimensions. Age differences were found most often on the chance and powerful others control dimensions, suggesting that the elderly acknowledge the importance of external sources of control and at the same time preserve their sense of internal control. In addition, the domain-specific scales were better predictors of behavioral outcomes within their respective domains for the elderly but not for the young. Findings suggest that multidimensional and domain-specific conceptions of control are advantageous for aging research. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of cultivar,location and year on total starch,amylose, phosphorus content and starch grain size of high starch potato cultivars for food and industrial processing

In recent time the interest of industry increases particularly in processing and use of potato high amylopectin (AMP) starches. Therefore the plant breeders effort to obtain “waxy” potato cultivars with low amylose (AMS) content. In this four-year study sixteen potato cultivars grown on five experimental locations were evaluated on the percentage of AMS/AMP by enzymatic method, starch content by the underwater weight method, phosphorus (P) content in starch digests spectrophotometrically, and starch granule size determined by laser diffraction method. Between enzymatic and iodine–potassium iodide method good correlation has been revealed (r = 0.71). The correlation analysis between AMS and P levels showed a clear negative correlation. For all measured parameters (starch, AMS, P, starch granule size) significant impact of cultivar has been determined. Location and year have lower, but significant impact. No statistically significant effect of year on AMS has been found. The cultivar Amado distinguished with the highest AMP and P contents and the cultivar Westamyl showed all positive values interesting for growers and processors.     

Interfacial load transfer in carbon nanotube/ceramic microfiber hybrid polymer composites

Growing carbon nanotubes (CNTs) on the surface of fibers has the potential to modify fiber–matrix interfacial adhesion, enhance the composite delamination resistance, and possibly improve its toughness and any matrix-dominated elastic property as well. In the present work aligned CNTs were grown upon ceramic fibers (silica and alumina) by chemical vapor deposition (CVD) at temperatures of 650 °C and 750 °C. Continuously-monitored single fiber composite (SFC) fragmentation tests were performed on pristine as well as on CNT-grown fibers embedded in epoxy. The critical fragment length, fiber tensile strength at critical length, and interfacial shear strength were evaluated. Significant increases (up to 50%) are observed in the fiber tensile strength and in the interfacial adhesion (which was sometimes doubled) with all fiber types upon which CNTs are CVD-grown at 750 °C. We discuss the likely sources of these improvements as well as their implications.     

Comparison of the total antioxidant status of Bohemian wines during the wine-making process

The total antioxidant status (TAS) of two white and two blue wine varieties from the ?ernoseky wine region (North Bohemia, Czech Republic) during the wine-making process was assessed by measurement with different radical scavenging assays: ABTS, DPPH and DMPD. Significant differences in the antioxidant activity between white and red wines were confirmed and changes of TAS during the wine production process were demonstrated. Moreover, differences were ascertained between individual varieties of red wine. No statistically significant relationship between the results provided by the ABTS and DPPH assays was found, obviously due to the fact that each phenolic substance in wine gives a different response to each specific radical used in the assay. The results obtained supported the assumption that variety plays a considerable role in TAS; the blue wine varieties showed a much higher TAS than did the white wines. The ABTS assay showed higher EQA (equivalents of ascorbic acid, mg/ml) values than the DPPH assay.