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Three experiments tested whether switching between strategies involves a cost. In three experiments, participants had to give approximate products to two-digit multiplication problems (e.g., 47×76). They were told which strategy to use (Experiments 1 and 2) or could choose among strategies (Experiment 3). The participants showed poorer performance when they used different strategies on two consecutive trials than when they used the same strategy. They also used the same strategy over two consecutive problems more often than they used different strategies. These effects, termed strategy switch costs , were found when the participants executed the easiest strategy and when they solved easy problems. We discuss possible processes underlying these strategy switch costs and the implications of these strategy switch costs for models of strategy choices.

Because of its sensitivity to unfavorable weather patterns, air pollution is sensitive to climate change so that, in the future, a climate penalty could jeopardize the expected efficiency of air pollution mitigation measures. A common method to assess the impact of climate on air quality consists in implementing chemistry-transport models forced by climate projections. However, the computing cost of such methods requires optimizing ensemble exploration techniques. By using a training data set from a deterministic projection of climate and air quality over Europe, we identified the main meteorological drivers of air quality for eight regions in Europe and developed statistical models that could be used to predict air pollutant concentrations. The evolution of the key climate variables driving either particulate or gaseous pollution allows selecting the members of the EuroCordex ensemble of regional climate projections that should be used in priority for future air quality projections (CanESM2/RCA4; CNRM-CM5-LR/RCA4 and CSIRO-Mk3-6-0/RCA4 and MPI-ESM-LR/CCLM following the EuroCordex terminology). After having tested the validity of the statistical model in predictive mode, we can provide ranges of uncertainty attributed to the spread of the regional climate projection ensemble by the end of the century (2071–2100) for the RCP8.5. In the three regions where the statistical model of the impact of climate change on PM2.5 offers satisfactory performances, we find a climate benefit (a decrease of PM2.5 concentrations under future climate) of −1.08 (±0.21), −1.03 (±0.32), −0.83 (±0.14) µg m−3, for respectively Eastern Europe, Mid-Europe and Northern Italy. In the British-Irish Isles, Scandinavia, France, the Iberian Peninsula and the Mediterranean, the statistical model is not considered skillful enough to draw any conclusion for PM2.5. In Eastern Europe, France, the Iberian Peninsula, Mid-Europe and Northern Italy, the statistical model of the impact of climate change on ozone was considered satisfactory and it confirms the climate penalty bearing upon ozone of 10.51 (±3.06), 11.70 (±3.63), 11.53 (±1.55), 9.86 (±4.41), 4.82 (±1.79) µg m−3, respectively. In the British-Irish Isles, Scandinavia and the Mediterranean, the skill of the statistical model was not considered robust enough to draw any conclusion for ozone pollution.

The last two decades of research in cognitive aging have seen a shift from simply describing age-related changes in cognitive performance to determining the mechanisms underlying these changes. Recent findings on variations in the use of cognitive strategies during aging further our understanding of how these changes in performance occur during adulthood. Data show age-related differences in strategy repertoire, strategy distribution, strategy execution, and strategy selection. I illustrate these findings in cognitive domains as varied as episodic memory, working memory, reasoning, decision making, problem solving, and language. I discuss how strategic variations are best studied both conceptually and methodologically and how investigating strategic variations helps us make significant progress in the study of cognitive aging. As I also show in this article, whichever the cognitive domain being studied, there are no restrictions that would prevent us from adopting a strategy perspective.

We present a compact holographic interferometer that uses a photorefractive crystal of the sillenite family as a holographic recording medium. Its development is based on a previous prototype that showed lack of flexibility and portability. We briefly discuss the main improvements leading to a compact device. Applications of this instrument in various metrological problems are shown, among which are two that were not already considered using holography, namely measurement of a thermal expansion coefficient and detection of fingerprints.

This in vivo biomechanical study was undertaken to analyze the consequences for sagittal balance and lumbar spine movement in three different lumbar disc prostheses. A total of 105 patients underwent total disc replacement in three different centers. The Maverick prosthesis was used in 46 patients, the SB Charité device was used in 49 patients and the Prodisc device was utilized in 10 patients. The analysis was computer assisted, using Spineview and Matlab softwares. The intra and inter-observer reliability and measurement uncertainty was performed. The analysis of lateral X-ray films in flexion-extension allowed to measure the prosthesis positioning, the range of motion (ROM), the localization of the mean center of rotation (MCR), the vertebral translation and the disc height, for each prosthesis device. The sagittal balance was analyzed on a full spine film. The parameters studied were described by Duval-Beaupère. The results were compared to the data found in literature, and compared to 18 asymptomatic volunteers, and 61 asymptomatic subjects, concerning the sagittal balance. The prostheses allowed an improvement of the ROM of less than 2 degrees. The ROM of L5-S1 prostheses ranged from 11.6 to 15.6% of the total lumbar motion during flexion-extension. At L4-L5 level, the ROM decreased when there was an arthrodesis associated at the L5-S1 level. There was no difference of ROM between the three prostheses devices. The MCR was linked to the ROM, but did not depend on the prosthesis offcentering. The disc height improved for any prosthesis, and decreased in flexion or in extension, when the prosthesis was offcentered. An increase of translation indicated a minor increase of the ROM at L4-L5 level after Maverick or SB Charité implantation. The L5-S1 arthrodesis was linked with an increase of the pelvic tilt. The lumbar lordosis curvature increased between L4 and S1, even more when a prosthesis was placed at the L3-L4 level. Total disc arthroplasty is useful in the surgical management of discogenic spinal pathology. The three prostheses studied allowed to retorate the disc height, the ROM, without disrupting the sagittal balance, but induced modification of the lumbar curvature.

We have released an archive of all observational data of the VUV spectrometer Solar Ultraviolet Measurements of Emitted Radiation (SUMER) on SOHO that have been acquired until now. The operational phase started with ‘first light’ observations on 27 January 1996 and will end in 2014. Future data will be added to the archive when they become available. The archive consists of a set of raw data (Level 0) and a set of data that are processed and calibrated to the best knowledge we have today (Level 1). This communication describes step by step the data acquisition and processing that has been applied in an automated manner to build the archive. It summarizes the expertise and insights into the scientific use of SUMER spectra that has accumulated over the years. It also indicates possibilities for further enhancement of the data quality. With this article we intend to convey our own understanding of the instrument performance to the scientific community and to introduce the new, standard FITS-format database.

Short stature and gonad failure can be a side effect of total body irradiation (TBI). The purpose of the study was to evaluate the factors influencing final height and gonad function after TBI. Fifty young adults given TBI during childhood were included. Twenty-seven had been treated with growth hormone (GH). Those given single 10 Grays (Gy) or fractionated 12 Gy TBI had similar characteristics, GH peaks, final heights and gonad function. After the end of GH treatment, 11/20 patients evaluated had GH peak >10 microg/l. Final height was <-2s.d. in 29 (58%). The height loss between TBI and final height (2.4+/-1.1 s.d.) was greater in those who were younger when irradiated (P<0.0001). When the GH-treated and -untreated patients were analyzed separately, this loss was correlated with the age at TBI at 4-8 years for the GH-treated and at 6-8 years for the untreated. Boys showed negative correlations between testicular volume and plasma follicle-stimulating hormone (FSH, P=0.0008) and between plasma FSH and inhibin B (P=0.005) concentrations. We concluded that the indications for GH treatment should be mainly based on the age at irradiation, taking into account the GH peak. The plasma FSH and inhibin B concentrations may predict sperm function.

We tested whether split effects in arithmetic (i.e., better performance on large-split problems, like 3 + 8 = 16, than on small-split problems, like 3 + 8 = 12) reflect decision processing or strategy selection. To achieve this end, we tested performance of younger and older adults, matched on arithmetic skills, on two arithmetic tasks: the addition/number comparison task (e.g., 4 + 8 □ 13; which item is the larger?) and in the inequality verification task (e.g., 4 + 8 < 13; Yes/No?). In both tasks, split between additions and proposed numbers were manipulated. We also manipulated the difficulty of the additions, which represents an index of arithmetic fact calculation (i.e., hard problems, like 6 + 8 < 15, are solved more slowly than easy problems, like 2 + 4 < 07, suggesting that calculation takes longer). Analyses of latencies revealed three main results: First, split effects were of smaller magnitude in older adults compared to younger adults, whatever the type of arithmetic task; second, split effects were of smaller magnitude on easy problems; and third, calculation processes were well maintained in older adults with high level of arithmetic skills. This set of results improves our understanding of cognitive aging and strategy selection in arithmetic. Dans les tâches classiques d'arithmétique, les participants vérifient plus lentement des problèmes dont le résultat proposé est proche du résultat correct (e.g., 7 × 4 = 26) que des problèmes dont le résultat proposé est éloigné (e.g., 7 × 4 = 38). Ces effets de distance reflèteraient soit un processus de décision, tel que suggéré par les approches classiques en arithmétique, soit l'utilisation de différentes stratégies, tel que suggéré par l'approche de sélection stratégique. Dans le domaine du vieillissement cognitif, les processus de décision sont affectés par l'âge. Pourtant, les effets de distance restent stables ou diminuent chez les adultes âgés. L'objectif de la présente étude était de déterminer les mécanismes impliqués dans les effets de distance en analysant les variations de performance entre les adultes jeunes et âgés dans différentes tâches arithmétiques. Des adutles jeunes et âgés, appariés sur le niveau de connaissances en arithmétique, ont réalisé deux tâches arithmétiques: dans une tâche de comparaison (e.g., 3 + 8 □ 16), les participants devaient décider lequel de l'addition ou du nombre était le plus grand et, dans une tâche de vérification (e.g., 3 + 8 < 16), ils devaient décider si le nombre était réellement plus grand que l'addition. Le materiel était identique pour les deux tâches et était factoriellement construit en fonction de la distance entre l'addition et le nombre et en fonction de la difficulté des additions. Seuls les processus de décision et de formulation de la réponse variaient entre les deux tâches. Les résultats s'accordent avec les prédictions dérivées de l'approche de sélection stratégique. Premièrement, les effets de distance diminuaient ches les adultes âgés par rapports aux jeunes, quelque soit le type de tâche arithmétique. Parallèlement, les processus de décision et de réponse, qui différaient entre les deux tâches, étaient affectés par l'âge. Deuxièmement, les effets de distance augmentaient sur les problèmes arithmétiques difficiles (e.g., 6 + 9 < 18) par rapport a des problèmes faciles (e.g., 2 + 3 < 7). Enfin, les effets de difficulté des additions n'augmentaient que chez les adultes âgés ayant un faible niveau de connaissances arithmétiques. L'ensemble de ces résultats suggère que les effets de distance reflètent un mécanisme de sélection stratégique: les problèmes de petite distance sont résolus avec des stratégies de calcul complet; ces stratégies sont court-circuitées sur les problèmes de grande distance grâce à des stratégies d'estimation. Avec l'âge, la sélection stratégique semble altérée: les adultes âgés utiliseraient majoritairement les stratégies de calcul complet sur l'ensemble des problèmes, car les processus de calcul sont relativement bien maintenus grâce aux connaissances arithmétiques.

Using combinations of amphibian embryo tissues, it is shown that the selection of genes expressed by a cell is determined by its distance from a source of activin, a peptide growth factor contained in vegetal cells and able to induce other cells to form mesoderm. This long-range signal spreads over at least 10 cell diameters in a few hours. It does so by passive diffusion, because it can by-pass cells that do not themselves respond to the signal nor synthesize protein. These results provide direct support for the operation of a morphogen concentration gradient in vertebrate development.