Children's strategies in computational estimation

International audienceWe investigated strategies used to estimate answers to addition problems. Two hundred and sixteen participants (72 adults, 72 sixth graders, and 72 fourth graders) had to provide estimates of three-by-three digit addition problems (e.g., 249 + 743). The choice/no-choice method was used to obtain unbiased estimates of the performance characteristics of strategies. Results showed that (a) at all ages, the most common strategy was to round both operands down to the closest smaller decades, (b) strategy use and execution were influenced by participants' age, problem features, and relative strategy performance, and (c) age-related changes in computational estimation include changes in relative strategy use and execution, as well as in the relative influences of problem and strategy characteristics on strategy choices. Implications of these findings for understanding age-related differences in strategic aspects of computational estimation performance are discussed. (C) 2002 Elsevier Science (USA). All rights reserved

Older and younger adults' strategy use and execution in currency conversion tasks: Insights from French franc to euro and euro to French franc conversions

International audienceYounger and older adults were taught new strategies for converting amounts presented in French francs into euros or amounts presented in euros into French francs. The choice/no-choice method was used to obtain information on how often each newly learned strategy was used as well as information on the speed and accuracy of strategies. The results showed that both younger and older participants used the new conversion strategies unequally often and had strategy preferences that were justified by the relative ease of execution of each strategy. We discuss numerous practical applications of the present findings, as they suggest that one can help younger and older people by teaching them the add-half and divide-three strategies for the French-franc-euro conversions, that no specific strategies should be taught to older people, and that newly taught strategies are more efficient than those people use spontaneously

Applying the choice/no-choice methodology: the case of children's strategy use in spelling

International audienceThe present study illustrates the usefulness of the choice/no-choice method to investigate age-related changes in children's strategies. This method enables independent assessments of strategy use and execution. It is applied in children's spelling strategies. Third- and fifth-grade children were asked to write down words using a dictionary or not (choice condition). Then, they were successively required to spell words using each strategy (no-choice condition). Performance showed that (a) strategy choices and accuracy differed in younger and older children, (b) strategy eft effectiveness was the strongest predictor of children's strategy use, and (c) having the choice resulted in higher level of spelling accuracy (especially in older children) than having no choice. We discuss the implications of these results on how the choice/no-choice method can be useful for understanding and investigating children's strategy choices in spelling and other cognitive domains

Adults' age-related differences in adaptivity of strategy choices: Evidence from computational estimation

International audienceFour experiments document adults' age-related changes in computational estimation performance and in adaptivity of strategy choices (i.e., the ability to choose the most precise strategy on each trial). Young and older adults were asked to provide estimates of 2-by-2-digit multiplication problems (e.g., 43 x 78) under varying conditions of speed and accuracy emphasis. The main findings showed that (a) older adults provided less accurate estimates and took more time to estimate, especially on the most difficult problems or when using harder strategies; (b) young and older adults had similar strategy preferences; and (c) older adults chose estimation strategies less adaptively than young adults. Implications of these findings for understanding strategic changes during adulthood in a wide variety of cognitive domains are discussed

`Strategy choices in French Francs/Euros conversion task'.

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Children's strategy use in computational estimation

International audienceThis study reports an investigation of ten-year-old children's strategy use in computational estimation (i.e., give an approximate answer like 400 to an arithmetic problem like 224 + 213). Children used four strategies: rounding with decomposition, rounding without decomposition, truncation, and compensation. Strategies appeared to differ in frequency and effectiveness. Finally, children chose strategies in an adaptive way so as to obtain fast and accurate performance. Implications of these findings for understanding children's computational estimation performance and strategies in numerical cognition in general are discussed

A CDMA2000 Zero IF Receiver with Low-Leakage Integrated Front-End

This paper describes a highly integrated CDMA 2000 US-CEL band (880-MHz) receiver. The single-chip zero-IF design incorporates all receiver signal-path functions including the low-noise amplifier (LNA) on a single die. The complete receiver design exceeds the stringent linearity and local oscillator (LO) leakage requirements for this standard arising from the coexistence with narrow-band FM signals. The integrated LNA achieves 1.0-dB noise figure with +9-dBm IIP3 at high gain, and by maintaining LO leakage to the antenna port well below 80~dBm at all gain settings, no external LNA is required. The receiver is fabricated in a 0.25-µm 40-GHz ft BICMOS technology, and occupies 3mm2

Blockade of pro-fibrotic response mediated by the miR-143/-145 cluster prevents targeted therapy-induced phenotypic plasticity and resistance in melanoma

Abstract Lineage dedifferentiation towards a mesenchymal-like state is a common mechanism of adaptive response and resistance to targeted therapy in melanoma. Yet, the transcriptional network driving this phenotypic plasticity remains elusive. Remarkably, this cellular state displays myofibroblast and fibrotic features and escapes MAPK inhibitors (MAPKi) through extracellular matrix (ECM) remodeling activities. Here we show that the anti-fibrotic drug Nintedanib/BIBF1120 is active to normalize the fibrous ECM network, enhance the efficacy of MAPK-targeted therapy and delay tumor relapse in a pre-clinical model of melanoma. We also uncovered the molecular networks that regulate the acquisition of this resistant phenotype and its reversion by Nintedanib, pointing the miR-143/-145 pro-fibrotic cluster as a driver of the therapy-resistant mesenchymal-like phenotype. Upregulation of the miR-143/-145 cluster under BRAFi/MAPKi therapy was observed in melanoma cells in vitro and in vivo and was associated with an invasive/undifferentiated profile of resistant cells. The 2 mature miRNAs generated from this cluster, miR-143-3p and miR-145-5p collaborated to mediate phenotypic transition towards a drug resistant undifferentiated mesenchymal-like state by targeting Fascin actin-bundling protein 1 (FSCN1), modulating the dynamic crosstalk between the actin cytoskeleton and the ECM through the regulation of focal adhesion dynamics as well as contributing to a fine-tuning of mechanotransduction pathways. Our study brings insights into a novel miRNA-mediated regulatory network that contributes to non-genetic adaptive drug resistance and provides proof-of-principle that preventing MAPKi-induced pro-fibrotic stromal response is a viable therapeutic opportunity for patients on targeted therapy