Experience-based mitigation of age-related performance declines: Evidence from air traffic control.

[Correction Notice: An erratum for this article was reported in Vol 15(2) of Journal of Experimental Psychology: Applied (see record 2009-09189-003). In the article, the URL published for the supplemental material was incorrect. The correct URL is http://dx.doi.org/10.1037/a0014947.supp] Previous research has found age-related deficits in a variety of cognitive processes. However, some studies have demonstrated age-related sparing on tasks where individuals have substantial experience, often attained over many decades. Here, the authors examined whether decades of experience in a fast-paced demanding profession, air traffic control (ATC), would enable older controllers to perform at high levels of proficiency. The authors also investigated whether older controllers would show diminished age-related decrements on domain-relevant cognitive abilities. Both young and old controllers and noncontrollers performed a battery of cognitive and ATC tasks. Results indicate that although high levels of experience can reduce the magnitude of age-related decline on the component processes that underlie complex task performance, this sparing is limited in scope. More important, however, the authors observed experience-based sparing on simulated ATC tasks, with the sparing being most evident on the more complex air traffic control tasks. These results suggest that given substantial experience, older adults may be quite capable of performing at high levels of proficiency on fast-paced demanding real-world tasks. The implications of these findings for global skilled labor shortages are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

FULLY DEVELOPED LAMINAR HEAT TRANSFER IN CIRCULAR-SEGMENT DUCTS WITH UNIFORM WALL TEMPERATURE

Heat transfer to constant-property, fully developed, laminar flows in circular-segment ducts with uniform wall temperature (T) has been analyzed. Besides representing a compact surface, the segment duct geometry models the flow cross section of a circular tube with a straight-tape insert. Two variations in the T thermal boundary condition are considered: constant axial and circumferential wall temperature, and constant temperature on the curved surface but an adiabatic flat wall. These two conditions model the extremes of the fin effects of a straight-tape insert, i.e., 100% and zero fin efficiencies, respectively. Numerical solutions, obtained by using finite difference techniques, are presented for both the velocity and temperature fields. The isothermal friction factors are in excellent agreement with analytical solutions reported in the literature. The Nusselt number results for the two thermal boundary conditions are presented for different segment shapes, 0° ≤, 6 ≤, 90°, and they represent the lower limits of the heat transfer enhancement due to twisted-tape inserts.     

The identity of psychoanalysis and psychoanalysts.

Psychoanalysis has been in a constant uninterrupted debate about its identity as a discipline and as a social institution. This article considers the place of science in psychoanalysis, on the one hand, and the hermeneutic nature of our discipline, on the other. The aim is to articulate a typology of psychoanalytic knowledge that characterizes psychoanalysis as a form of therapy, an intellectual movement, and a theoretical system. This typology considers psychoanalysis as a thought collective that influences its members by exchanging and maintaining ideas. To be a well-rounded psychoanalytic thinker or practitioner one must be able to move easily among three realms of knowledge--the humanities, the social sciences, and the natural sciences. Each realm has its own criteria of truth and the challenge is to know when to employ which criteria. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A New Model Compound for Studying Alkaline Cellulose Chain Cleavage Reactions

A conformationally rigid cellulose model, the 4′,6′-O-benzylidene derivative of 1,5-anhydrocellobiitol, has been studied to learn more about the mechanisms of chain cleavage reactions under alkaline pulping conditions. Heating the model at 170°C in 2.5N NaOH gave 55% glycon-oxygen (G-O) bond cleavage, and ～45% oxygen-aglycon (O-A) bond cleavage. The amount of observed O-A bond cleavage is significantly higher than that for 1,5-anhydrocellobiitol. The benzylidene model also degraded about ～35% faster than 1,5-anhydrocellobiitol; much of this rate increase can be attributed to a faster rate of O-A bond cleavage for the benzylidene model. The greater amount of O-A bond cleavage in the benzylidene case may be attributable to a more highly substituted glycosyl ring (making the ring a better anion leaving group) and/or to a more conformationally inflexible glycosyl ring. The inflexibility restricts one of the standard G-O bond cleavage mechanisms, namely the S_NicB(2′) mechanism. The results point out the value of choosing appropriate cellulose models.     

Morphological and Elemental Classification of Freshly Emitted Soot Particles and Atmospheric Ultrafine Particles using the TEM/EDS

The Transmission Electron Microscopy (TEM) and Energy Dispersive Spectroscopy (EDS) were used to determine morphology and elemental composition of a variety of freshly emitted soot particles (acetylene flame, candle flame, kerosene flame, diesel exhaust, electric arc, plastic burning, styrofoam burning, wood burning [white oak and pine bark], and rice straw burning), which can be possible candidate soot in the ambient atmosphere, and ultrafine particles sampled in urban, industrial, and coastal sites during ultrafine particle formation events (combustion and photochemical events). By using mobility-classified non-refractory ((NH ₄ ) ₂ SO ₄ ) and refractory (Polystyrene latex (PSL) and salt (NaCl)) particles, limitation of the TEM was tested. Data showed that the TEM method can be used to examine shapes of both volatile particles such as (NH ₄ ) ₂ SO ₄ (100 nm) at low, but not high magnification (refer to low and high beam intensity, respectively), and non-volatile particles like NaCl (100 nm) and PSL (84 nm) at either low or high magnification. Distinct differences in morphological properties such as primary particle diameter, fractal dimension, and microstructure were observed among the different types of fresh soot particles. The atmospheric ultrafine particles were classified as agglomerates, sulfate mixtures (spherical), metallic oxides (spherical and polygonal), C-rich refractory (not agglomerated), C-rich non-refractory (not agglomerated), Si-rich (spherical), Na-rich (porous), or P-containing (non-spherical) particles. At the urban Gwangju site, a higher fraction of fresh and aged agglomerates was observed than at other sites. The C-rich non-refractory and sulfate mixtures were often observed in the photochemical event. The C-rich refractory particles were abundant at the Gwangju and Yeosu sites. The coastal Taean site had few agglomerates due to limited anthropogenic combustion source.     

Comparison of the Chemical and Oxidative Characteristics of Particulate Matter (PM) Collected by Different Methods: Filters,Impactors, and BioSamplers

In this study, we compare the chemical and oxidative characteristics of concentration-enriched PM_2.5 samples simultaneously collected by a filter, a Nano-Micro-Orifice Uniform Deposition Impactor, and a BioSampler. Gravimetric measurements showed considerable agreement in particulate matter (PM) collection efficiency for all three samplers. Accordingly, samples from the three collectors exhibited similar chemical compositions. The mass fractions of their inorganic ions, labile and nonlabile, were comparable. Moreover, the organic carbon (OC) content of the BioSampler slurry was similar to that of the filter, while water-soluble OC levels of the filter and impactor samples were close to a 100% agreement. Lastly, linear regression analyses demonstrated that the water-soluble elements existed in similar proportions for the filter and impactor samples. Their respective total components were also in very good agreement. By contrast, the recoverable elements from the BioSampler slurry, determined by high-resolution magnetic sector inductively coupled plasma mass spectrometry, were in good agreement with the water-soluble elements of the filter and impactor samples but not their corresponding total components. In spite of the overall agreement among the samples on their chemical composition, findings from a macrophage reactive oxygen species (ROS), a dithiothreitol (DTT), and a dihydroxybenzoate (DHBA) assay revealed that the oxidative potential of aqueous extracts of the filter and impactor substrates was similar yet substantially lower than that of the BioSampler slurry. However, filtering of the BioSampler slurry, i.e., removal of insoluble PM components, attenuated its ROS activity to about the same level as that of the water extracts of the filter and impactor samples. These findings first indicate that insoluble PM species are potentially redox active, and second that particle collection by the BioSampler, which circumvents the need for PM extraction, constitutes a viable alternative for collecting concentrated particles for characterization of the oxidative properties of PM.     

Hydride Formation in Zirconium Alloys

The ingress of hydrogen during corrosion in service can degrade the mechanical properties of zirconium alloy nuclear fuel cladding because of the formation of brittle hydrides. The formation of these hydrides is reviewed in light of recent synchrotron radiation experimental results and phase-field modeling computational results that provide new insight on the process.     

Essentiality of fatty acids

All fatty acids have important functions, but the term “essential” is applied only to those polyunsaturated fatty acids (PUFA) that are necessary for good health and cannot be completely synthesized in the body. The need for arachidonic acid, which is utilized for eicosanoid synthesis and is a constituent of membrane phospholipids involved in signal transduction, is the main reason why the n-6 class of PUFA are essential. Physiological data indicate that n-3 PUFA also are essential. Although eicosapentaenoic acid also is a substrate for eicosanoid synthesis, docosahexaenoic acid (DHA) is more likely to be the essential n-3 constituent because it is necessary for optimal visual acuity and neural development. DHA is present in large amounts in the ethanolamine and serine phospholipids, suggesting that its function involves membrane structure. Because the metabolism of n-6 PUFA is geared primarily to produce arachidonic acid, only small amounts of 22-carbon n-6 PUFA are ordinarily formed. Thus, the essentiality of n-3 PUFA may be due to their ability to supply enough 22-carbon PUFA for optimal membrane function rather than to a unique biochemical property of DHA.