Setting goals to switch between tasks: Effect of cue transparency on children’s cognitive flexibility.

Three experiments examined the difficulty of translating cues into verbal representations of task goals by varying the degree of cue transparency (auditory transparent cues, visual transparent cues, visual arbitrary cues) in the Advanced Dimensional Change Card Sort, which requires switching between color- and shape-sorting rules on the basis of cues. Experiment 1 showed that 5- and 6-year-old children’s performance improved as a function of cue transparency. Experiment 2 yielded the same pattern of results and showed that cue transparency effects cannot be accounted for by cue format only. Finally, Experiment 3 examined the effect of cue transparency in 7- and 9-year-olds and adults. The effect decreased over age for accuracy performance but not for latencies, suggesting that under some conditions, the difficulty of cue translation can still be observed in individuals whose inner speech is efficient. Overall, these findings showed that goal setting substantially contributes to children’s flexible behaviors and continues to influence adults’ performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of third-body particles on wear rate in unicondylar knee arthroplasty: a wear simulator study with bone and cement debris

The reduced intraoperative visibility of minimally invasive implanted unicondylar knee arthroplasty makes it difficult to remove bone and cement debris, which have been reported on the surface of damaged and retrieved bearings. Therefore, the aim of this study was to analyze the influence of bone and cement particles on the wear rate of unicompartmental knee prostheses in vitro. Fixed bearing unicompartmental knee prostheses were tested using a knee-wear-simulator according to the ISO standard 14243-1:2002(E) for 5.0 million cycles. Afterwards bone debris (particle size 671 ± 262 μm) were added to the test fluid in a concentration of 5 g/l for 1.5 million cycles, followed by 1.5 million cycles blended with cement debris (particle size 644 ± 186 μm) in the same concentration. Wear rate, knee-kinematics and wear-pattern were analyzed. The wear rate reached 12.5 ± 1.0 mm³/million cycles in the running-in and decreased during the steady state phase to 4.4 ± 0.91 mm³/million cycles. Bone particles resulted in a wear rate of 3.0 ± 1.27 mm³/million cycles with no influence on the wear rate compared to the steady state phase. Cement particles, however, lead to a significantly higher wear rate (25.0 ± 16.93 mm³/million cycles) compared to the steady state phase. The careful removal of extruded cement debris during implantation may help in reducing wear rate. Bone debris are suggested to have less critical influence on the prostheses wear rate.     

Experimental Data Highlighting the Role of Surface Fracture Energy in Quasi-Static Confined Comminution

Since the pioneering work of Griffith, Linear Elastic Fracture Mechanics has been widely experimentally validated and successfully developed in solid mechanics modeling. However, recent theoretical models applying the energy balance found in Griffith theory specifically for quasi-static confined comminution have until now not been systematically confronted to experiments. In this study, we analyze data of compression tests on crushable sand, where grain breakage has been triggered by flooding the initially dry material at constant stresses. We consider a partition of the dissipation between surface fracture energy and the rearrangement of fragments and grains surrounding crushed particles. Our results show that the role of the surface fracture energy is stressdependent and that its influence becomes less significant at high stresses.     

Decidability of Equivalence of Symbolic Derivations

We give in this paper an alternative, and we believe simpler, proof of a deep result by Mathieu Baudet, namely that the equivalence of symbolic constraints is decidable for deduction systems on a finite signature modulo a subterm convergent equational theory.     

A constitutive model for granular materials considering grain breakage

A particle breakage has a significant impact on the mechanical behavior of granular materials. In this paper, we present an elasto-plastic model with two yield surfaces to which the influence of particle breakage has been introduced. The main feature of this model is to incorporate the change in the critical state line (CSL) consequent to the grain breakage induced by isotropic and deviatoric stresses during loading. For this purpose we propose a breakage function which connects the evolution of the CSL to ...     

Effects of Chromia Coatings on the High-Temperature Behavior of F17Ti Stainless Steel in Air: Analytical Studies of the Effect of Rare-Earth-Element Oxides

The MOCVD deposition of neodymium oxide and/orchromium oxide provided beneficial effects both onisothermal- and cyclic high-temperature behavior ofcommercial F17Ti stainless steel. Fracture crosssections provided information about the morphology ofthe oxide scales formed on bare steel and coatedspecimens. The chromia scales developed small equiaxedgrains on the Nd₂O₃-coated samplesand columnar grains on the uncoated ones. Neo dymium segregatedwithin a surface layer composed ofMn_1.5Cr_1.5O₄ spineloxide. A complex phase (close to the structure ofCeTi₂₁O₃₈) was identified in thiszone. It could act as a source of neodymium ions, which couldsegregate to the grain boundaries of the chromia scale.Polished cross sections associated with X-ray mappingstudies confirmed the scale structure and the location of the rare-earth element in the outer part ofthe oxide layer.     

Young's modulus repeatability assessment using cycling compression loading on cancellous bone

For various applications, precision of the Young's modulus of cancellous bone specimens is needed. However, measurement variability is rarely given. The aim of this study was to assess the Young's modulus repeatability using a uniaxial cyclic compression protocol on embedded specimens of human cancellous bone. Twelve specimens from 12 human calcanei were considered. The specimens were first defatted and then 1 or 2 mm at the ends were embedded in an epoxy resin. The compression experiment consists in applying 20 compressive cycles between 0.2 per cent and 0.6 per cent strain with a 2 Hz loading frequency. The coefficient of variation of the current protocol was found to be 1.2 percent. This protocol showed variability similar to the end-cap technique (considered as a reference). It can be applied on porous specimen (especially human bone) and requires minimal bone length to limit end-artifact variability. The current method could be applied in association with noninvasive measurements (such as ultrasound) with full compatibility. This possibility opens the way for bone damage follow-up based on Young's modulus monitoring.     

Structure of tetrathallium methylene diphosphonate

Tl₄CH₂0₆P₂ was found to be monoclinic C2/c, a = 12.647 (6), b = 8.314 (5), c = 9.782 (4), β = 103.0 (9)°, Z = 4. The structure was solved with MULTAN and refined to R(Fo) = 0.075 for 1636 reflections measured with MoKα radiation. The crystal structure can be regarded as being built up of isolated MDP linked together by Tl⁺ ions.     

New insights into optimal widely linear array receivers for the demodulation of BPSK, MSK, and GMSK signals corrupted by noncircular interferences-application to SAIC

For nonstationary observations, potentially second-order (SO) noncircular, the SO optimal complex filters are time variant and, under some conditions of noncircularity, widely linear (WL). For more than a decade, there has been an increasing interest in optimal WL filters in radiocommunications contexts involving rectilinear signals such as binary phase-shift keying (BPSK) signals. In particular, it has been pointed out that single antenna interference cancellation (SAIC) may be performed by such filters in the context of BPSK cellular networks. Recently, it has been shown that, by a simple algebraic operation of demodulation on the baseband signal, the minimum shift keying (MSK) and Gaussian MSK (GMSK) modulations can be made to approximately correspond to a BPSK modulation, allowing the application of the SAIC concept to the GSM cellular network at the mobile level, being currently studied for standardization, and offering significant improvements of the network's capacity. Despite the increasing interest in optimal WL filters in rectilinear or quasi-rectilinear contexts, many questions about their behavior and their performance have still arisen. The purpose of this paper is to gain insight into the behavior, properties, and performance of optimal WL array receivers, and thus of the SAIC technology, for the demodulation of BPSK, MSK, and GMSK signals corrupted by noncircular interferences.