Microfoundations of Problem Solving: Attentional Engagement Predicts Problem-Solving Strategies

Organizations use a plethora of methods and tools to help their members solve problems effectively. Yet the specifics of how individuals solve problems remain largely unexplored. We propose and test a cognitive model of problem solving that integrates dual process theories into the attention-based view. The model suggests that diverse problem-solving strategies emerge in response to how individuals deliberate. Three studies provide observational and causal evidence in support of our model. The first study explores the strategies managers use to solve problems. We use think-aloud protocols combined with content, sequence, and cluster analyses to extract the key differences in how experienced managers solve problems. Two problem-solving strategies emerge from the data: one emphasizes mental activities related to framing, and the other emphasizes mental activities related to implementation. In the second study, we use a mixed factorial experimental design and mouse-tracking analysis to uncover the causal mechanism that explains the emergence of these two strategies. We then retest our hypotheses in a third, preregistered, study. We find that manipulating attention toward mental activities related to framing increases deliberation aimed at restructuring the problem elements. In contrast, directing attention toward mental activities related to implementation increases deliberation on the potential contingencies and consequences of the solution. Our findings provide empirical evidence about how problems are actually solved and support the idea that attentional processes are malleable enough to affect the choice of problem-solving strategies

Isotropic-nematic transition in hard-rod fluids: relation between continuous and restricted-orientation models

We explore models of hard-rod fluids with a finite number of allowed orientations, and construct their bulk phase diagrams within Onsager's second virial theory. For a one-component fluid, we show that the discretization of the orientations leads to the existence of an artificial (almost) perfectly aligned nematic phase, which coexists with the (physical) nematic phase if the number of orientations is sufficiently large, or with the isotropic phase if the number of orientations is small. Its appearance correlates with the accuracy of sampling the nematic orientation distribution within its typical opening angle. For a binary mixture this artificial phase also exists, and a much larger number of orientations is required to shift it to such high densities that it does not interfere with the physical part of the phase diagram.Comment: 4 pages, 2 figures, submitted to PR

Circulating microparticles from pulmonary hypertensive rats are vectors of oxidative stress

Date du colloque : 04/2010National audienc

Multiphasic on/off pheromone signalling in moths as neural correlates of a search strategy

Insects and robots searching for odour sources in turbulent plumes face the same problem: the random nature of mixing causes fluctuations and intermittency in perception. Pheromone-tracking male moths appear to deal with discontinuous flows of information by surging upwind, upon sensing a pheromone patch, and casting crosswind, upon losing the plume. Using a combination of neurophysiological recordings, computational modelling and experiments with a cyborg, we propose a neuronal mechanism that promotes a behavioural switch between surge and casting. We show how multiphasic On/Off pheromone-sensitive neurons may guide action selection based on signalling presence or loss of the pheromone. A Hodgkin-Huxley-type neuron model with a small-conductance calcium-activated potassium (SK) channel reproduces physiological On/Off responses. Using this model as a command neuron and the antennae of tethered moths as pheromone sensors, we demonstrate the efficiency of multiphasic patterning in driving a robotic searcher toward the source. Taken together, our results suggest that multiphasic On/Off responses may mediate olfactory navigation and that SK channels may account for these responses

Rapid angular expansion of the ionized core of CRL 618

Context. During the transition from the asymptotic giant branch (AGB) to the planetary nebulae phase the circumstellar envelopes of most low- and intermediate-mass stars experience a dramatic change in morphology. CRL 618 exhibits characteristics of both an AGB and post-AGB star. It also displays a spectacular array of bipolar lobes with a dense equatorial region, which makes it an excellent object for studying the development of asymmetries in evolved stars. In recent decades, an elliptical compact HII region located in the center of the nebula has been seen to be increasing in size and flux. This seems to be due to the ionization of the circumstellar envelope by the central star, and it probably indicates the beginning of the planetary nebula phase for CRL 618. Aims. We aim to determine the physical conditions under which the ionization of the circumstellar envelope of CRL 618 began to take place as well as the subsequent propagation of the ionization front. Methods. We analyzed interferometric radio continuum data at ~5 and 22 GHz from observations carried out at seven epochs with the VLA. We traced the flux increase of the ionized region over a period of ~26 years. We measured the dimensions of the HII region directly from the brightness distribution images to determine the increase of its size over time. For one of the epochs we analyzed observations at six frequencies from which we estimated the electron density distribution. We carried out model calculations of the spectral energy distribution at two different epochs to corroborate our observational results. Results. We found that the radio continuum flux and the size of the ionized region have been increasing monotonically in the past three decades. The size of the major axis of the HII region shows a dependance on frequency, which has been interpreted as a result of the gradient of the electron density in this direction. The growth of the HII region is due to the expansion of an ionized wind whose mass-loss rate increased continuously for a period of ~100 years until a few decades ago, when the mass-loss rate experienced a sudden decline. Our results indicate that the circumstellar envelope began to be ionized around 1971, which marks the start of the planetary nebula phase of CRL 618. © ESO, 2013

Efficient powder blending in support of plutonium conversion for mixed oxide fuel

This paper describes a unique system that is used to mix and blend multiple batches of plutonium oxide powder of various consistencies into an equivalent number of identical and homogeneously mixed batches. This system is being designed and built to support the Advanced Recovery and Integrated Extraction System (ARIES) at the Los Alamos TA-55 Plutonium Facility. The ARIES program demonstrates dismantlement of nuclear pits, retrieval of the plutonium components, and conversion of the plutonium into an oxide for eventual use in mixed oxide (MOX) fuel for nuclear reactors. The purpose of this powder blending work is to assure that ARIES oxide is converted into an unclassified homogeneous mixture and that consistent feed material is available for MOX fuel assembly. This blending system is being assembled in a selected glovebox a TA-55 using an LANL designed split/combine apparatus, a commercial Turbula blending unit, and several additional supporting hardware components