A model for the postcollapse equilibrium of cosmological structure: truncated isothermal spheres from top-hat density perturbations

The postcollapse structure of objects which form by gravitational condensation out of the expanding cosmological background universe is a key element in the theory of galaxy formation. Towards this end, we have reconsidered the outcome of the nonlinear growth of a uniform, spherical density perturbation in an unperturbed background universe - the cosmological ``top-hat'' problem. We adopt the usual assumption that the collapse to infinite density at a finite time predicted by the top-hat solution is interrupted by a rapid virialization caused by the growth of small-scale inhomogeneities in the initial perturbation. We replace the standard description of the postcollapse object as a uniform sphere in virial equilibrium by a more self-consistent one as a truncated, nonsingular, isothermal sphere in virial and hydrostatic equilibrium, including for the first time a proper treatment of the finite-pressure boundary condition on the sphere. The results differ significantly from both the uniform sphere and the singular isothermal sphere approximations for the postcollapse objects. These results will have a significant effect on a wide range of applications of the Press-Schechter and other semi-analytical models to cosmology. The truncated isothermal sphere solution presented here predicts the virial temperature and integrated mass distribution of the X-ray clusters formed in the CDM model as found by detailed, 3D, numerical gas and N-body dynamical simulations remarkably well. This solution allows us to derive analytically the numerically-calibrated mass-temperature and radius-temperature scaling laws for X-ray clusters which were derived empirically by Evrard, Metzler and Navarro from simulation results for the CDM model. (Shortened)Comment: 29 pages, 7 ps figures, MNRAS-style, LaTeX. Accepted for publication in MNRAS. Minor revisions only (including additional panel in Fig.3 and additional comparison with X-ray cluster simulations

A virtual versus an augmented reality cooking task based-tools: a behavioral and physiological study on the assessment of executive functions.

[EN] Virtual reality (VR) and augmented reality (AR) are two novel graphics immersive techniques (GIT) that, in the last decade, have been attracting the attention of many researchers, especially in psychological research. VR can provide 3D real-life synthetic environments in which controllers allow human interaction. AR overlays synthetic elements to the real world and the human gaze to target allow hand gesture to act with synthetic elements. Both techniques are providing more ecologically environments than traditional methods, and most of the previous researches, on one side, have more focused on the use of VR for treatment and assessment showing positive effectiveness results. On the other, AR has been proving for the treatment of specific disorders but there are no studies that investigated the feasibility and effectiveness of augmented reality in the neuropsychological assessment. Starting from these premises, the present study aimed to compare the performance and sense of presence using both techniques during an ecological task, such as cooking. The study included 50 cognitively healthy subjects. The cooking task consisted of 4 levels that increased in difficulty. As the level increased, additional activities appeared. The order of presentation of each exposure condition (AR and VR) was counterbalanced for each participant. The virtual reality-cooking task has been performed through ¿HTC/VIVE¿ and augmented reality through ¿Microsoft HoloLens¿.¿Furthermore, the study recorded and compared the psychophysiological changes (heart rate and skin conductance response) during the cooking task in both conditions. To measure the sense of presence occurring during the two exposure conditions, subjects completed the SUSQ and the ITC-SOPI immediately after each condition. The behavioral results showed that times are always lower in VR than in AR, increasing constantly in accordance with the difficulty of the tasks. Regarding physiological responses, the findings showed that AR condition produced more individual excitement and activation than VR. Finally, VR was able to produce higher levels of sense of presence than AR condition. The overall results support that VR currently represents the GIT with greater usability and feasibility compared to AR, probably due to the differences in the human-computer interaction between the two techniques.Chicchi-Giglioli, IA.; Bermejo Vidal, C.; Alcañiz Raya, ML. (2019). A virtual versus an augmented reality cooking task based-tools: a behavioral and physiological study on the assessment of executive functions. Frontiers in Psychology. 1-12. https://doi.org/10.3389/fpsyg.2019.02529S112Barratt, E. S. (1959). Anxiety and Impulsiveness Related to Psychomotor Efficiency. 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Young Children Learning Languages in a Multilingual Context

Luxembourg is a trilingual country where residents communicate in Luxembourgish, French and German concurrently. Children therefore study these languages at primary school. In this paper I explore how six eight-year-old Luxembourgish children use and learn German, French and English in formal and informal settings over a period of one year. Their eagerness to learn and use German and English contrasted with their cautious and formal approach to the learning of French. My findings demonstrate that second language learning in a multilingual country is not an 'automatic' or 'natural' process but, rather, children's language behaviour depends on their personal goals, interests, competence, confidence and understanding of what counts as appropriate language use. These factors are influenced by the formal approach to language learning at school

Placebo from an enactive perspective

Due to their complexity and variability, placebo effects remain controversial. We suggest this is also due to a set of problematic assumptions (dualism, reductionism, individualism, passivity). We critically assess current explanations and empirical evidence and propose an alternative theoretical framework—the enactive approach to life and mind—based on recent developments in embodied cognitive science. We review core enactive concepts such as autonomy, agency, and sense-making. Following these ideas, we propose a move from binary distinctions (e.g., conscious vs. non-conscious) to the more workable categories of reflective and pre-reflective activity. We introduce an ontology of individuation, following the work of Gilbert Simondon, that allow us to see placebo interventions not as originating causal chains, but as modulators and triggers in the regulation of tensions between ongoing embodied and interpersonal processes. We describe these interrelated processes involving looping effects through three intertwined dimensions of embodiment: organic, sensorimotor, and intersubjective. Finally, we defend the need to investigate therapeutic interactions in terms of participatory sense-making, going beyond the identification of individual social traits (e.g., empathy, trust) that contribute to placebo effects. We discuss resonances and differences between the enactive proposal, popular explanations such as expectations and conditioning, and other approaches based on meaning responses and phenomenological/ecological ideas

Mechanisms of Reactions of Sulfur Hydride Hydroxide: Tautomerism, Condensations, and C‑Sulfenylation and O‑Sulfenylation of 2,4-Pentanedione

The conformations, equilibrium structures, hydrogen bonds, and non-covalent interactions involved in the mechanisms of tautomerization, condensations, and C-sulfenylation and O-sulfenylation of 2,4-pentanedione by sulfur hydride hydroxide (hydrogen thioperoxide, oxadisulfane, H–SOH) have been studied using BD­(T), CCSD­(T), and QCISD­(T) with the cc-pVTZ basis set and using B3LYP, B3PW91, CAM-B3LYP, PBE1PBE, PBEh1PBE, LC-ωPBE, M06-2X, and ωB97XD with the 6-311+G­(d,p) basis set. All levels of theory predict the sulfenyl (H–SOH) tautomer of hydrogen thioperoxide to be lower in energy than the sulfinyl (H₂SO) tautomer. Four reasonable mechanisms were considered for the tautomerization of the sulfenyl tautomer of hydrogen thioperoxide to the sulfinyl tautomer: a cyclic three-membered water-free transition state (<b>TS</b>, CCSD­(T) activation energy barrier <i>E</i>^⧧ = 65.1 kcal/mol), a cyclic five-membered transition state with one water molecule (<b>TS</b>H₂O, <i>E</i>^⧧ = 31.1 kcal/mol), a cyclic seven-membered transition state with two water molecules (<b>TS</b>2H₂O, <i>E</i>^⧧ = 14.5 kcal/mol), and a cyclic nine-membered transition state with three water molecules (<b>TS</b>3H₂O, <i>E</i>^⧧ = 5.6 kcal/mol). The mechanisms involve hydrogen-bonded reactant complexes and hydrogen-bonded product complexes. The CCSD­(T)-predicted energy barriers for the condensation of hydrogen thioperoxide to form thiosulfinic acid through transition states with zero, one, and two waters are <i>E</i>^⧧ = 42.0, 18.3, and 0 kcal/mol, respectively. Mixed condensation reactions are predicted to afford organosulfur products and compounds containing sulfur–selenium bonds. Hydrogen thioperoxide is predicted to add to 2,4-pentanedione to form C-sulfenylated (sulfide, thioether) and O-sulfenylated (sulfenate ester) products. Similar mechanistic trends and reaction pathways are observed in the tautomerism, condensations, and C-sulfenylation and O-sulfenylation reactions of hydrogen thioperoxide. The water molecules set up proton relay networks (bridges) that reduce ring strain, generate favorable conformations for reactivity, lower energy barriers, and increase the numbers of stabilizing hydrogen bonds and nonbonding interactions