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A series of recent debates in experimental economics have associated demand effects with the artificiality of the experimental setting and have linked it to the problem of external validity. In this paper, we argue that these associations can be misleading, partly because of the ambiguity with which "artificiality" has been defined, but also because demand effects and external validity are related in complex ways. We argue that artificiality (understood as unfamiliarity of the experimental environment) may be directly as well as inversely correlated with demand effects. We also distinguish between the demand effects of experimentation and the reactions that they may trigger and that might endanger experimental validity. We conclude that economists should pay more attention to the way in which subjects construe the experimental task and learn to exploit subjects' reactivity to expectations in their experiments.

A series of recent debates in experimental economics have associated demand effects with the artificiality of the experimental setting and have linked it to the problem of external validity. In this paper, we argue that these associations can be misleading, partly because of the ambiguity with which "artificiality" has been defined, but also because demand effects and external validity are related in complex ways. We argue that artificiality (understood as unfamiliarity of the experimental environment) may be directly as well as inversely correlated with demand effects. We also distinguish between the demand effects of experimentation and the reactions that they may trigger and that might endanger experimental validity. We conclude that economists should pay more attention to the way in which subjects construe the experimental task and learn to exploit subjects' reactivity to expectations in their experiments

This study examined the affect of social support intervention on decreasing psychological and physiological stress. Fifty-seven college students, who scored below the median on functional, structural, and satisfaction measures of social support, were recruited. They were randomly assigned to a social support intervention group or a wait-list control group. The social support treatment condition consisted of 1-hour sessions designed to increase levels of structural and functional support. Participants completed self-report inventories measuring daily stress, physical symptoms, depression, anxiety, and social support both prior to and after treatment. After, participants participated in a laboratory-based psychophysiological assessment that measured their cardiovascular reactivity to a social stressor. Results did not suggest the beneficial effects of a social support intervention on physiological and psychological stress. Both groups showed improvement on most measures. The possible reasons for this are length and content of the intervention, the selection criteria of participants, and group process variables.

AbstractDuring early childhood, harsh and emotionally negative parent–child exchanges are expected to increase children's risk for developing later conduct problems. The present study examined longitudinal associations between the quality of parenting responses and children's distress reactivity during children's second year of life. Forty‐seven mother–child dyads completed observational assessments of children's distress reactivity and mothers' harsh and supportive parenting when children were 12 and 24 months of age. Results indicated that mothers' contingent harsh parenting responses to children's non‐compliance when children were 12 months of age predicted increases in children's observed distress from 12 to 24 months, but children's level of distress at 12 months did not predict change in harsh parenting responses over the same time period. In contrast, supportive parenting contingent responses did not predict declines in children's distress reactivity, although children's distress reactivity predicted declines in mothers' supportive parenting responses from 12 to 24 months. Results are discussed in terms of the implications of the quality of parent–child interactions as a point of entry onto developmental pathways of risk.

The first chemical modification on the endohedral HF@C60 is reported. In particular, the isomerization from optically pure (2S,5S)-cis-pyrrolidinofullerene 2b to (2S,5R)-trans-pyrrolidinofullerene 2b has been studied and compared with empty C60 (2a) and endo-hedral H2O@C60 (3). Interestingly, the incarcerated HF molecule contributes to increase the isomerization rate through a H-bonding assistance involving weak hydrogen bonding without affecting the final cis-trans ratio or promoting the loss of enantioselective control through the retro-cycloaddition reaction. The comparative study shows a kinetic order for the isomerization process of H2O@C60 ˃ HF@C60 ˃ C60, thus confirming the effect of the incarcerated species on the zwitterionic intermediate stability ; This work was supported by the European Research Council ERC-320441-Chirallcarbon, Ministerio de Economía y Competitividad (MINECO) of Spain (project CTQ2014-52045-R) and the CAM (FOTOCARBON project S2013/MIT-2841). R.J.W. and S.A. thank the Engineering and Physical Sciences Research Council (UK) for funding this work (EP/1029451, M001962, M001970) including core capability (EP/K039466). M.I. thanks to Ministerio de Economía y Competitividad (MINECO) of Spain (Juan de la Cierva-Incorporación IJCI-2014-19320). We are also grateful for financial support from the Spanish MINECO (CTQ2014-54306-P, CTQ2014-59212-P, and RyC contract RYC-2014-16846 to S.O.), the Catalan DIUE (2014SGR931, ICREA Academia 2014 Award to M.S. and XRQTC), and the FEDER fund (UNGI10-4E-801). M.G.-B. thanks the Ramón Areces Foundation for a Postdoctoral Fellowship and S.O. the European Commission for CIG project (FP7-PEOPLE-2013-CIG630978), and the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (ERC-2015-StG-679001). Excellent service from computational centers CSUC and BSC-CNS is acknowledged. NM thanks to EC FP7 ITN "MOLESCO" Project No. 606728

Permission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint fees. ; Currently, the use of silica fume for the production of mortars and high-performance concrete is of great importance to the construction materials sector. Different applications of silica fume have generated extensive studies about its high reactivity as a pozzolanic material, in addition to its effect on the properties of some materials within which it is incorporated. In this study a sonication process was applied by means of which the deagglomeration of the larger particles of densi¿ed silica fume (CSF) was achieved. The result is a CSF treated with the ultrasound probe, which is obtained for different tests where the parameters of sonication such as sonication power level and sonication time are varied. This treatment makes it possible to increase the quantity of submicrometric particles in the sample. The effect of sonication process on CSF produces a greater quantity of very ¿ne particles, which improve the pozzolanic reactivity of silica fume and increase the ¿xation of hydrated lime. This behaviour also produces higher mechanical strength in mortars manufactured with sonicated silica fume (SSF). The mechanical strengths of SSF mortars were greater than those for control and CSF mortar. Different percentages of cement were substituted (between 0 and 15% by weight), and in all cases the SSF mortars showed important differences from the CSF mortar. It was observed that for the longest sonication times and highest sonication power levels, mechanical strengths were increased. ; The authors are grateful to the Spanish company Ferroatlantica S.L. for their financial support; to the Spanish Agency of International Cooperation and Development (AECID) for the doctorate grant to D.M.-V.; to the Spanish government for their support to the project BIA 2007-63252; and to FEDER for its financial support to our research projects. ; Martínez Velandia, DA.; Paya Bernabeu, JJ.; Monzó ...

<b><i>Introduction:</i></b> Although the effects of proximal smoking cues have been widely studied in smokers, little is known on the features associated with background spatial context effect, that is, "context reactivity." The aim of this study was to investigate context reactivity exhibited by smokers in virtual cue-free domestic scenarios. <b><i>Methods:</i></b> Sixty-nine participants divided in 2 cohorts (33 smokers and 36 non-smokers) were exposed to a virtual reality session with 4 domestic room scenarios presented in a balanced order: bedroom, bathroom, kitchen, and living room. <b><i>Results:</i></b> We showed that (i) it is possible to elicit smoking craving in smokers in virtual reality, and (ii) these effects are room dependent and (iii) associated with a lower sense of presence; furthermore, (iv) smokers reported higher craving scores for alcohol and food in a room-dependent fashion compared to non-smokers. <b><i>Conclusion:</i></b> Our study provides an experimental paradigm for assessing context reactivity in smokers and suggests a potential use for the identification of non-pharmacological interventions as a co-adjuvant of smoking cessation treatment.