1,307 research outputs found

    Social comparisons are associated with poorer and riskier financial decision making, no matter whether encounters are sporadic or repeated

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    Previous research suggests that social comparisons affect decision making under uncertainty. However, the role of the length of the social interaction for this relationship remains unknown. This experiment tests the effect of social comparisons on financial risk taking and how this effect is modulated by whether social encounters are sporadic or repeated. Participants carried out a computer task consisting of a series of binary choices between lotteries of varying profitability and risk, with real monetary stakes. After each decision, participants could compare their own payoff to that of a counterpart who made the same decision at the same time and whose choices/earnings did not affect the participants’ earnings. The design comprised three between-subjects treatments which differed in the nature of the social interaction: participants were informed that they would be matched with either (a) a different participant in each trial, (b) the same participant across all trials, or (c) a "virtual participant", i.e. a computer algorithm. Compared to the non-social condition (c), subjects in both social conditions (a and b) chose lotteries with lower expected value (z=-3.10, p<0.01) and higher outcome variance (z=2.13, p=0.03). However, no differences were found between the two social conditions (z=1.15, p=0.25 and z=0.35, p=0.73, respectively). These results indicate that social comparison information per se leads to poorer and riskier financial decisions, irrespective of whether or not the referent other is encountered repeatedly

    Optical absorption of divalent metal tungstates: Correlation between the band-gap energy and the cation ionic radius

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    We have carried out optical-absorption and reflectance measurements at room temperature in single crystals of AWO4 tungstates (A = Ba, Ca, Cd, Cu, Pb, Sr, and Zn). From the experimental results their band-gap energy has been determined to be 5.26 eV (BaWO4), 5.08 eV (SrWO4), 4.94 eV (CaWO4), 4.15 eV (CdWO4), 3.9-4.4 eV (ZnWO4), 3.8-4.2 eV (PbWO4), and 2.3 eV (CuWO4). The results are discussed in terms of the electronic structure of the studied tungstates. It has been found that those compounds where only the s electron states of the A2+ cation hybridize with the O 2p and W 5d states (e.g BaWO4) have larger band-gap energies than those where also p, d, and f states of the A2+ cation contribute to the top of the valence band and the bottom of the conduction band (e.g. PbWO4). The results are of importance in view of the large discrepancies existent in prevoiusly published data.Comment: 16 pages, 3 figures, 1 tabl

    Synchronization of the Frenet-Serret linear system with a chaotic nonlinear system by feedback of states

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    A synchronization procedure of the generalized type in the sense of Rulkov et al [Phys. Rev. E 51, 980 (1995)] is used to impose a nonlinear Malasoma chaotic motion on the Frenet-Serret system of vectors in the differential geometry of space curves. This could have applications to the mesoscopic motion of biological filamentsComment: 12 pages, 7 figures, accepted at Int. J. Theor. Phy

    Anionic surfactant biodegradation in seawater

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    The authors conducted a study of the influence of several environmental factors (temperature, salinity, luminosity, aeration and the presence of sediments) on the biodegradation of a commercial anionic surfactant (LAS) in waters and sediments of Cadiz Bay (southwest Iberian Peninsula). The assay was carried out using an adaptation of the river die-away test. At temperatures of 20-25 °C, degradation exceeded 90 % within less than 10 days of assays, whereas at temperatures under 10 °C, degradation scarcely took place. Luminosity increases the degradation speed, compared with assays performed under darkness. Finally, the results show that the rate of surfactant degradation was remarkably accelerated in the presence of sediments, except in those tests where anoxic conditions were established.Se presenta un estudio de la influencia de diversas variables ambientales, tales como temperatura, salinidad, luminosidad, aireación, etc., en el proceso de biodegradación de un tensioactivo aniónico comercial (LAS) en aguas y sedimentos de la bahía de Cádiz (suroeste de la península Ibérica). El ensayo se ha llevado a cabo empleando una modificación del método test de agua de río. A temperaturas de 20 y 25 °C, el nivel de degradación superaba el 90 % en menos de 10 días de ensayo, mientras a temperaturas inferiores a los 10 °C, apenas tenía lugar degradación alguna. La iluminación provoca un aumento de la velocidad de degradación respecto a los ensayos llevados a cabo en oscuridad. Los resultados han mostrado que la velocidad de degradación del tensioactivo se ve claramente aumentada por la presencia de sedimentos, excepto en aquellos casos en los que se dieron condiciones anóxicas.Instituto Español de Oceanografí

    One-dimensional dynamics of nearly unstable axisymmetric liquid bridges

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    A general one-dimensional model is considered that describes the dynamics of slender, axisymmetric, noncylindrical liquid bridges between two equal disks. Such model depends on two adjustable parameters and includes as particular cases the standard Lee and Cosserat models. For slender liquid bridges, the model provides sufficiently accurate results and involves much easier and faster calculations than the full three-dimensional model. In particular, viscous effects are easily accounted for. The one-dimensional model is used to derive a simple weakly nonlinear description of the dynamics near the instability limit. Small perturbations of marginal instability conditions are also considered that account for volume perturbations, nonequality of the supporting disks, and axial gravity. The analysis shows that the dynamics breaks the reflection symmetry on the midplane between the supporting disks. The weakly nonlinear evolution of the amplitude of the perturbation is given by a Duffing equation, whose coefficients are calculated in terms of the slenderness as a part of the analysis and exhibit a weak dependence on the adjustable parameters of the one-dimensional model. The amplitude equation is used to make quantitative predictions of both the (first stage of) breakage for unstable configurations and the (slow) dynamics for stable configurations

    High-pressure structural investigation of several zircon-type orthovanadates

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    Room temperature angle-dispersive x-ray diffraction measurements on zircon-type EuVO4, LuVO4, and ScVO4 were performed up to 27 GPa. In the three compounds we found evidence of a pressure-induced structural phase transformation from zircon to a scheelite-type structure. The onset of the transition is near 8 GPa, but the transition is sluggish and the low- and high-pressure phases coexist in a pressure range of about 10 GPa. In EuVO4 and LuVO4 a second transition to a M-fergusonite-type phase was found near 21 GPa. The equations of state for the zircon and scheelite phases are also determined. Among the three studied compounds, we found that ScVO4 is less compressible than EuVO4 and LuVO4, being the most incompressible orthovanadate studied to date. The sequence of structural transitions and compressibilities are discussed in comparison with other zircon-type oxides.Comment: 34 pages, 2 Tables, 11 Figure

    Accuracy of the fetal cerebroplacental ratio for the detection of intrapartum compromise in nonsmall fetuses.

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    OBJECTIVE: To study the accuracy of the cerebroplacental ratio (CPR) for the detection of intrapartum fetal compromise (IFC) in fetuses growing over the 10th centile. METHODS: This was a prospective study of 569 nonsmall fetuses attending the day hospital unit of a tertiary hospital that underwent an ultrasound examination at 36-40 weeks, and were delivered within 4 weeks of examination. IFC was defined as a composite of: abnormal intrapartum fetal heart rate or intrapartum fetal scalp pH < 7.20 requiring cesarean section, neonatal umbilical cord pH < 7.20, 5' Apgar score < 7 and postpartum admission to neonatal or pediatric intensive care units. The accuracy of CPR for the prediction of IFC was calculated alone and in combination with other perinatal parameters using univariate and multivariate logistic regression models, which alternatively included the onset of labor to evaluate the influence of induction of labor (IOL) on IFC and a brief composite adverse outcome of two parameters to prove the strength of the approach. RESULTS: The incidence of IFC was 17.9%. CPR sensitivity was 30.4% for a false positive rate (FFR) of 10 and 14.7% for a FPP of 5% (AUC = 0.62, p < 0.001). The multivariate analysis showed that only fetal gender and parity increased the predictive accuracy of CPR alone, although the improvement was poor (AUC = 0.67, p < 0.001). No differences were observed using any of the alternative models. Finally, IOL had no influence of IFC. CONCLUSION: Despite their apparent normality, a proportion of fetuses growing over the 10th centile suffer IFC. Some of them are suitable for detection by means of CPR

    Generalities on Private Equity and Venture Capital Funds: a current review of the industry and its environment in Mexico

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    Private Equity and Venture Capital Funds have shown an exceptional resilience in Mexico and there are good reasons to think they will experience a strong growth in the coming years, although they still represent a very small portion of the gross domestic investment in comparison with other countries of similar economic development. Nevertheless, it is necessary to implement many important legal and other institutional reforms that have proved to contribute to the successful evolution of this industry before it may be considered a new economic development engine for the country.Capital Privado, Capital Emprendedor, Fondos

    INNOVACIONES INTERNACIONALES EN ROBÓTICA MÉDICA PARA MEJORAR EL MANEJO DEL PACIENTE EN PERÚ: INTERNATIONAL INNOVATIONS IN MEDICAL ROBOTICS TO IMPROVE THE PATIENT MANAGEMENT IN PERU

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    Surgical Engineering Society conducted a research, the First Review as the pioneers in LATAM, since year 2015, which develops the topic of the latest Medical Robotics technologies created in North América, Europe and Asia, which are imported to apply in the Healthcare System of Peru and Latin America. The robotic systems for surgery, rehabilitation and assistance are presented covering the description of control design and technical specifications. Besides, the patient management using robots is analyzed with diagnosis, prognosis and treatment tools. The process to evaluate the new inventions of robotic devices and bring to the market is introduced where three stages are shown as the following: innovation, regulatory affairs and biomedical application. Moreover, there is a high percentage of population with disability in Latin America, therefore, it is necessary that more biomedical scientists be specialized in robotics to start developing new ideas to improve the patient management. Finally, the new technologies created in Latin America must be affordable, simply and efficient in order to support the healthcare economic situation in the continent and give the best quality standards to improve treatment outcomes on patients.Surgical Engineering Society realizó una investigación, la primera revisión como pioneros en LATAM, desde el año 2015, que desarrolla el tema de las últimas tecnologías de robótica médica creadas en América del Norte, Europa y Asia, que se importan para aplicarlas en el sistema de salud de Perú y América Latina Los sistemas robóticos para cirugía, rehabilitación y asistencia se presentan cubriendo la descripción del diseño del control y las especificaciones técnicas. Además, el manejo del paciente mediante robots se analiza con herramientas de diagnóstico, pronóstico y tratamiento. El proceso para evaluar los nuevos inventos de los dispositivos robóticos y llevarlo al mercado se introduce donde en las tres etapas que se muestran a continuación: innovación, asuntos regulatorios y aplicación biomédica. Además, hay un alto porcentaje de población con discapacidad en América Latina, por lo tanto, es necesario que más científicos biomédicos se especialicen en robótica para comenzar a desarrollar nuevas ideas y mejorar el manejo del paciente. Finalmente, las nuevas tecnologías creadas en América Latina deben ser asequibles, simples y eficientes para apoyar la situación económica de la atención médica en el continente y brindar los mejores estándares de calidad para mejorar los resultados del tratamiento en los pacientes
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