On the theoretical-numerical study of the ITER Upper Port Plug structure hydraulic behaviour under steady state and draining and drying transient conditions

The ITER diagnostic Upper Port Plug (UPP) is a water-cooled stainless steel structure aimed to integrate within vacuum vessel the plasma diagnostic systems, shielding them from neutron and photon irradiation. Due to the very intense heat loads expected, a proper cooling circuit has been designed to ensure an adequate UPP cooling with an acceptable thermal rise and an unduly high pumping power and to perform its draining and drying procedure by injection of pressurized nitrogen.A theoretical research activity has been launched at the Department of Nuclear Engineering of the University of Palermo aiming to investigate the hydraulic behaviour of the UPP Trapezoid Section cooling circuit under steady state conditions and during its draining and drying transient procedure. The research activity has been performed following a theoretical-computational approach and adopting the RELAP5 thermal-hydraulic system code.The Trapezoid Section cooling circuit characteristic functions have been derived under steady state conditions at various coolant temperatures for both the coolant flow paths at the present under consideration for this circuit. The distributions of coolant mass flow rates along the channels of the cooling circuit have been calculated too. Results show that the flow path characterized by right plate inlet has improved hydraulic performances.The transient behaviour of the Trapezoid Section cooling circuit has been investigated during the draining and drying operational transient procedure, considering realistic operative scenarios, for both the coolant flow paths at the present under consideration for the cooling circuit. In particular, it has been found out that the recently proposed flow path seems to allow the complete draining of the Trapezoid Section circuit, eliminating the need for the drying procedure.     

The strength and fracture toughness of 18 Ni (350) maraging steel

The influence of microstructure on the strength and fracture toughness of 18 Ni (350) maraging steel was examined. Changes in microstructure were followed by X-ray and neutron diffraction and by optical and electron microscopy. These observations have been correlated with the fracture morphology established by scanning electron microscopy. Air cooling this alloy from the austenitizing temperature results in a dislocated martensite. During the initial stage of age hardening, molybdenum atoms tend to cluster (forming preprecipitates) and the cobalt assumes short range ordered positions. Subsequent aging results in Ni₃Mo and σ-FeTi with overaging being associated with the formation of equilibrium reverted austenite and Fe₂Mo. The fracture behavior is examined in terms of elementary dislocation precipitate interactions. It is suggested that the development of coplanar slip in the underaged conditions leads to its increased stress corrosion susceptibility and decreased fracture toughness. The optimum aged condition is then associated with cross-slip deformation. The fracture behavior of the overaged condition is a dynamic balance between a brittle matrix and the ductile (crack blunting) reverted austenite.     

Simplified learning in complex situations: Knowledge partitioning in function learning.

The authors explored the phenomenon that knowledge is not always integrated and consistent but may be partitioned into independent parcels that may contain mutually contradictory information. In 4 experiments, using a function learning paradigm, a binary context variable was paired with the continuous stimulus variable of a to-be-learned function. In the first 2 experiments, when context predicted the slope of a quadratic function, generalization was context specific. Because context did not predict function values, it is suggested that people use context to gate separate learning of simpler partial functions. The 3rd experiment showed that partitioning also occurs with a decreasing linear function, whereas the 4th study showed that partitioning is absent for a linearly increasing function. The results support the notion that people simplify complex learning tasks by acquiring independent parcels of knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gold, jade, and emeruby: The value of naturalness for theories of concepts and categories.

Researchers studying the psychology of concepts frequently draw distinctions between artificial and natural concepts. Unfortunately, there is a lack of consensus regarding the foundations and implications of the distinction. This paper provides a review and evaluation of the different ways researchers have approached the question of conceptual naturalness. Accounts may be divided into 2 approaches described as psychologically or externally based. These characterizations motivate distinctive sets of research questions. In addition to the particular implications, the author also considers the general significance of a distinction between natural and artificial concepts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Competing strategies in categorization: Expediency and resistance to knowledge restructuring.

The authors investigated people's ability to restructure their knowledge when additional information about a categorization task is revealed. In 2 experiments, people first learned to rely on a fairly accurate (but imperfect) predictor. At various points in training, a complex relationship between 2 other predictors was revealed in a schematic diagram that could support perfect performance. In Experiment 1, people adopted the complex strategy when it was revealed at the outset but were unable to restructure their knowledge after the expedient predictor had been learned. In Experiment 2, expedient knowledge persisted even with an adaptive display. The persistence of expedient knowledge is explained by associative blocking of potential alternative cues. A 3rd experiment analyzed the strategies people use with and without the diagram. The study confirmed that the diagram, when presented at the outset, significantly alters people's approach to the task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental study of gravitational disturbances during Solar eclipses in the Novosibirsk region

Tidal variations of gravity Δg measured with an error smaller than 1 μGal = 1·10⁻⁸ m/s² during the Solar eclipses on July 31, 1981 and August 1, 2008 with the absolute laser ballistic gravimeters developed and fabricated by the authors are presented.     

Immune complex-dissociated p24 antigen in congenital or perinatal HIV infection: role in the diagnosis and assessment of risk of infection in infants

Both suppressor oncogene and proliferative activity are believed to indicate colon cancer risk. The retinoblastoma (Rb) gene is a suppressor oncogene affecting cell differentiation. Retinoblastoma gene inactivation is associated with tumour development. However, the relation of the Rb protein to cell proliferation and colon tumour formation is unknown. Retinoblastoma protein quantity was correlated with proliferative activity in flat, unaffected mucosa specimens from 36 cancer patients, 21 non-cancer control subjects and in 29 tumour tissue samples from cancer patients. Nuclear Rb protein was measured by using automated CAS-200 image analysis of monoclonal antibody labelled frozen sections from fresh, surgically removed tissue. All colon cells within 15 whole crypts were imaged. Proliferative activity was also measured by using analysis with Ki-67 monoclonal antibody. Retinoblastoma protein content correlated directly with proliferative activity in flat mucosa of non-cancer control subjects (r = 0.63; P < 0.001; n = 21). A significant correlation was also found in flat mucosa specimens of non-metastatic (Duke's stages A and B) cancer patients (r = 0.52; P < 0.01; n = 22). However, Rb protein did not correlate with proliferation in flat mucosa from metastatic (Duke's stages C and D) cancer patients (r = 0.03; NS; n = 14) or in cancer tissue (r = 0.068; NS; n = 29). Mucosal Rb protein in the colon normally increases as proliferation increases. Dissociation between Rb protein and colon proliferation may occur in flat mucosa in patients with a higher risk of metastatic tumour growth. Future studies comparing Rb protein quantity and proliferative activity may help identify high-risk colon cancer patients.     

Terahertz and Infrared Surface Wave Beams and Pulses on Gyrotropic,Nonlinear and Metamaterial Interfaces

This work is devoted to theoretical study of surface plasmon polariton propagation on metal or metamaterial – dielectric interfaces where media can possess optical or magnetooptical activity or cubic nonlinearity. On the interface of gyrotropic media surface wave changes its polarization and profile as well as in case of interface of media with cubic nonlinearity. Surface wave propagation constant can be modified by magnetization leading to magnetooptical intensity effect. The properties of plasmons in gratings are also considered including excitation, dispersion and existence of various types of modes. The theory of surface wave and pulsed beam diffraction in gyrotropic, nonlinear and layered media is developed. We also present waveguide for surface waves based on layered metamaterial – dielectric interfaces suppressing diffraction spreading.     

Design and validation of a high-throughput matrix-assisted laser desorption ionization time-of-flight mass spectrometry method for quantification of hepcidin in human plasma

Disorders of iron metabolism affect over a billion people worldwide. The circulating peptide hormone hepcidin, the central regulator of iron distribution in mammals, holds great diagnostic potential for an array of iron-associated disorders, including iron loading (β-thalassemia), iron overload (hereditary hemochromatosis), and iron deficiency diseases. We describe a novel high-throughput matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry assay for quantification of hepcidin in human plasma. This assay involves enrichment using a functionalized MALDI chip, a novel solvent-detergent precipitation buffer, and quantification using a stable isotope labeled internal standard. The linear range of hepcidin in plasma was 1-120 nM, with a low limit of quantification (LOQ) (1 nM), high accuracy (<15% relative error (RE)), and high precision (intraday average 5.52-18.48% coefficient of variation (CV) and interday 9.32-14.83% CV). The assay showed strong correlation with an established hepcidin immunoassay (Spearman; R(2) = 0.839 n = 93 ethylenediaminetetraacetic acid (EDTA) plasma). A collection of normal healthy pediatric samples (range 3.8-32.5 ng/mL; mean 12.9 ng/mL; n = 119) showed significant differences from an adult collection (range 1.8-48.7 ng/mL; mean 16.1 ng/mL; n = 95; P = 0.0096). We discuss these preliminary reference ranges and correlations with additional parameters in light of the utility and limitations of hepcidin measurements as a stand-alone diagnostic and as a tool for therapeutic intervention.     

Preschoolers' understanding of mental and bodily reactions to contamination: What you don't know can hurt you, but cannot sadden you.

Evidence of the operation of a biological theory might be found in children's distinction between mental (emotional) and bodily (illness) reactions to contamination. Study 1 explored whether children see emotions as voluntary but illness as outside of intentional control. Three- and 5-yr-olds judged that simple volitions were insufficient to alter either outcome. Study 2 suggested that children distinguish reactions mediated by representations from those mediated by physical interactions. Children indicated that knowledge determines mental reactions to contamination, but physical contact determines bodily reactions. Study 3 explored knowledge about particulars of emotional and illness reactions. Most preschoolers did not realize that illness takes time to develop. These data suggest that preschoolers do distinguish between physical and mental reactions to contamination but have a poor understanding of the actual bodily processes involved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)