609 research outputs found

    Neural correlates of informational cascades: brain mechanisms of social influence on belief updating

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    Informational cascades can occur when rationally acting individuals decide independently of their private information and follow the decisions of preceding decision-makers. In the process of updating beliefs, differences in the weighting of private and publicly available social information may modulate the probability that a cascade starts in a decisive way. By using functional magnetic resonance imaging, we examined neural activity while participants updated their beliefs based on the decisions of two fictitious stock market traders and their own private information, which led to a final decision of buying one of two stocks. Computational modeling of the behavioral data showed that a majority of participants overweighted private information. Overweighting was negatively correlated with the probability of starting an informational cascade in trials especially prone to conformity. Belief updating by private information was related to activity in the inferior frontal gyrus/anterior insula, the dorsolateral prefrontal cortex and the parietal cortex; the more a participant overweighted private information, the higher the activity in the inferior frontal gyrus/anterior insula and the lower in the parietal-temporal cortex. This study explores the neural correlates of overweighting of private information, which underlies the tendency to start an informational cascad

    Probing the Deep End of the Milky Way with New Oscillating Kepler Giants

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    The Kepler mission has been a success in both exoplanet search and stellar physics studies. Red giants have actually been quite a highlight in the Kepler scene. The Kepler long and almost continuous four-year observations allowed us to detect oscillations in more than 15,000 red giants targeted by the mission. However by looking at the power spectra of 45,000 stars classified as dwarfs according to the Q1-16 Kepler star properties catalog, we detected red-giant like oscillations in 850 stars. Even though this is a small addition to the known red-giant sample, these misclassified stars represent a goldmine for galactic archeology studies. Indeed they happen to be fainter (down to Kp~16) and more distant (d>10kpc) than the known red giants, opening the possibility to probe unknown regions of our Galaxy. The faintness of these red giants with detected oscillations is very promising for detecting acoustic modes in red giants observed with K2 and TESS. In this talk, I will present this new sample of red giants with their revised stellar parameters derived from asteroseismology. Then I will discuss about the distribution of their masses, distances, and evolutionary states compared to the previously known sample of red giants.Comment: 5 pages, 4 figures, Proceedings of the KASC9-TASC2 meetin

    Bounding Counterfactuals under Selection Bias

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    Causal analysis may be affected by selection bias, which is defined as the systematic exclusion of data from a certain subpopulation. Previous work in this area focused on the derivation of identifiability conditions. We propose instead a first algorithm to address both identifiable and unidentifiable queries. We prove that, in spite of the missingness induced by the selection bias, the likelihood of the available data is unimodal. This enables us to use the causal expectation-maximisation scheme to obtain the values of causal queries in the identifiable case, and to compute bounds otherwise. Experiments demonstrate the approach to be practically viable. Theoretical convergence characterisations are provided.Comment: Eleventh International Conference on Probabilistic Graphical Models (PGM 2022

    Suppression of Quadrupole and Octupole Modes in Red Giants Observed by Kepler

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    An exciting new theoretical result shows that observing suppression of dipole oscillation modes in red giant stars can be used to detect strong magnetic fields in the stellar cores. A fundamental facet of the theory is that nearly all the mode energy leaking into the core is trapped by the magnetic greenhouse effect. This results in clear predictions for how the mode visibility changes as a star evolves up the red giant branch, and how that depends on stellar mass, spherical degree, and mode lifetime. Here, we investigate the validity of these predictions with a focus on the visibility of different spherical degrees. We find that mode suppression weakens for higher degree modes with a reduction in the quadrupole mode visibility of up to 49%, and no detectable suppression of octupole modes, in agreement with theory. We find evidence for the influence of increasing mode lifetimes on the visibilities along the red giant branch, in agreement with previous independent observations. These results support the theory that strong internal magnetic fields cause suppression of non-radial modes in red giants. We also find preliminary evidence that stars with suppressed dipole modes on average have slightly lower metallicity than normal stars

    International Conference on Continuous Optimization (ICCOPT) 2019 Conference Book

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    The Sixth International Conference on Continuous Optimization took place on the campus of the Technical University of Berlin, August 3-8, 2019. The ICCOPT is a flagship conference of the Mathematical Optimization Society (MOS), organized every three years. ICCOPT 2019 was hosted by the Weierstrass Institute for Applied Analysis and Stochastics (WIAS) Berlin. It included a Summer School and a Conference with a series of plenary and semi-plenary talks, organized and contributed sessions, and poster sessions. This book comprises the full conference program. It contains, in particular, the scientific program in survey style as well as with all details, and information on the social program, the venue, special meetings, and more

    IAP Studie 2017 : der Mensch in der Arbeitswelt 4.0

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    Digitalisierung prägt die «neue» Arbeitswelt. Neue Technologien, agile Arbeitsformen, mobil-flexible Arbeitsplätze und andere Entwicklungen beeinflussen, wie und wo wir in Zukunft arbeiten. Das Internet verändert unsere Vorstellungen von Arbeit und auch die Rolle des Menschen in der Wirtschaft. Die vorliegende IAP Studie fokussiert auf den Menschen in der Arbeitswelt 4.0. Das IAP Institut für Angewandte Psychologie hat mehr als 600 Schweizer Fach- und Führungskräfte befragt, wie sie die Veränderungen in der neuen Arbeitswelt erleben und inwieweit Digitalisierung in ihren Arbeitsalltag vorgedrungen ist. Seit 2011 bezeichnet «4.0» als Kurzformel die Umwälzungen der digitalen Transformation (Kagermann & Lukas, 2011). Arbeitswelt 4.0 steht für das Arbeiten während der laufenden vierten industriellen Revolution. Diese beinhaltet, dass über das mobile Internet und das «Internet der Dinge» ein neuer Teil unserer Lebens- und Arbeitswelten datentechnisch erfasst, vernetzt, ausgewertet und optimiert werden kann. Es entstehen neue Arbeitsprozesse, Geschäftsmodelle, Organisationsstrukturen, neue Berufsbilder und neue Anforderungen an Mitarbeitende. Doch wie gelingt in Organisationen eine erfolgreiche digitale Transformation? Es liegen bereits zahlreiche Trend-Reports zum Thema Digitalisierung vor. Consulting-Firmen geben Ratschläge für neue Business-Modelle, Wirtschaftswachstum und Effizienzsteigerung, die dank digitaler Transformation, künstlicher Intelligenz und Big Data möglich werden sollen. Bisherige Studien zu digitaler Transformation setzen in der Regel auf technologische Investitionen zur Innovationsförderung und wagen grosse Zukunftsprognosen. Medien verkünden potenziell grosse Verluste von Arbeitsplätzen durch den digitalen Wandel. Die IAP Studie legt auf der Basis von Zahlen eine differenzierte Einschätzung der Arbeitswelt 4.0 vor und stellt dabei den Menschen in einer sich digitalisierenden Arbeitswelt ins Zentrum. Am Ende des Tages beeinflusst das Zusammenspiel von Mensch und Maschine den künftigen Erfolg von Firmen und Organisationen

    Enhanced equal frequency partition method for the identification of a water demand system

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    This paper deals with unsupervised partitioning. A first goal of this paper is to present an enhancement to the Equal Frequency Partition (EFP) method that allows to reduce, to some extent, the main drawback of this classical classification method, i.e. the data distribution dependency. A second goal of this work is to use the Enhanced Equal Frequency Partition (EEFP) method within the discretization process of the Fuzzy Inductive Reasoning (FIR) methodology for the identification of a model of a water demand system. It is shown that use of the EEFP method allows to obtain more accurate FIR models of the water demand system, reducing the prediction errors.Peer ReviewedPostprint (author's final draft

    Analysis of the Flow in a Typified USBR II Stilling Basin through a Numerical and Physical Modeling Approach

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    [EN] Adaptation of stilling basins to higher discharges than those considered for their design implies deep knowledge of the flow developed in these structures. To this end, the hydraulic jump occurring in a typified United States Bureau of Reclamation Type II (USBR II) stilling basin was analyzed using a numerical and experimental modeling approach. A reduced-scale physical model to conduct an experimental campaign was built and a numerical computational fluid dynamics (CFD) model was prepared to carry out the corresponding simulations. Both models were able to successfully reproduce the case study in terms of hydraulic jump shape, velocity profiles, and pressure distributions. The analysis revealed not only similarities to the flow in classical hydraulic jumps but also the influence of the energy dissipation devices existing in the stilling basin, all in good agreement with bibliographical information, despite some slight differences. Furthermore, the void fraction distribution was analyzed, showing satisfactory performance of the physical model, although the numerical approach presented some limitations to adequately represent the flow aeration mechanisms, which are discussed herein. Overall, the presented modeling approach can be considered as a useful tool to address the analysis of free surface flows occurring in stilling basins.This research was funded by 'Generalitat Valenciana predoctoral grants (Grant number [2015/7521])', in collaboration with the European Social Funds and by the research project: 'La aireacion del flujo y su implementacion en prototipo para la mejora de la disipacion de energia de la lamina vertiente por resalto hidraulico en distintos tipos de presas' (BIA2017-85412-C2-1-R), funded by the Spanish Ministry of Economy.Macián Pérez, JF.; García-Bartual, R.; Huber, B.; Bayón, A.; Vallés-Morán, FJ. (2020). Analysis of the Flow in a Typified USBR II Stilling Basin through a Numerical and Physical Modeling Approach. Water. 12(1):1-20. https://doi.org/10.3390/w12010227S120121Bayon, A., Valero, D., García-Bartual, R., Vallés-Morán, F. ​José, & López-Jiménez, P. A. (2016). Performance assessment of OpenFOAM and FLOW-3D in the numerical modeling of a low Reynolds number hydraulic jump. Environmental Modelling & Software, 80, 322-335. doi:10.1016/j.envsoft.2016.02.018Chanson, H. (2008). Turbulent air–water flows in hydraulic structures: dynamic similarity and scale effects. Environmental Fluid Mechanics, 9(2), 125-142. doi:10.1007/s10652-008-9078-3Heller, V. (2011). Scale effects in physical hydraulic engineering models. Journal of Hydraulic Research, 49(3), 293-306. doi:10.1080/00221686.2011.578914Chanson, H. (2013). Hydraulics of aerated flows:qui pro quo? Journal of Hydraulic Research, 51(3), 223-243. doi:10.1080/00221686.2013.795917Blocken, B., & Gualtieri, C. (2012). Ten iterative steps for model development and evaluation applied to Computational Fluid Dynamics for Environmental Fluid Mechanics. Environmental Modelling & Software, 33, 1-22. doi:10.1016/j.envsoft.2012.02.001Wang, H., & Chanson, H. (2015). Experimental Study of Turbulent Fluctuations in Hydraulic Jumps. Journal of Hydraulic Engineering, 141(7), 04015010. doi:10.1061/(asce)hy.1943-7900.0001010Valero, D., Viti, N., & Gualtieri, C. (2018). Numerical Simulation of Hydraulic Jumps. Part 1: Experimental Data for Modelling Performance Assessment. Water, 11(1), 36. doi:10.3390/w11010036Viti, N., Valero, D., & Gualtieri, C. (2018). Numerical Simulation of Hydraulic Jumps. Part 2: Recent Results and Future Outlook. Water, 11(1), 28. doi:10.3390/w11010028Bayon-Barrachina, A., & Lopez-Jimenez, P. A. (2015). Numerical analysis of hydraulic jumps using OpenFOAM. 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Numerical Simulation of Air–Water Two-Phase Flow on Stepped Spillways Behind X-Shaped Flaring Gate Piers under Very High Unit Discharge. Water, 11(10), 1956. doi:10.3390/w11101956Toso, J. W., & Bowers, C. E. (1988). Extreme Pressures in Hydraulic‐Jump Stilling Basins. Journal of Hydraulic Engineering, 114(8), 829-843. doi:10.1061/(asce)0733-9429(1988)114:8(829)Houichi, L., Ibrahim, G., & Achour, B. (2006). Experiments for the Discharge Capacity of the Siphon Spillway Having the Creager-Ofitserov Profile. International Journal of Fluid Mechanics Research, 33(5), 395-406. doi:10.1615/interjfluidmechres.v33.i5.10Padulano, R., Fecarotta, O., Del Giudice, G., & Carravetta, A. (2017). Hydraulic Design of a USBR Type II Stilling Basin. Journal of Irrigation and Drainage Engineering, 143(5), 04017001. doi:10.1061/(asce)ir.1943-4774.0001150Hirt, C. ., & Nichols, B. . (1981). Volume of fluid (VOF) method for the dynamics of free boundaries. 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    IAP Studie 2017 – Teil 2 : der Mensch in der Arbeitswelt 4.0: Ergebnisse der qualitativen Interviews

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    https://www.zhaw.ch/de/psychologie/institute/iap/iap-studie

    Hemogram of healthy sheep (Ovisaries) of the Santa Ines breed raised in the region of Piedade, São Paulo State: influence of age and sex

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    Foi investigada a influência dos fatores etários e sexuais sobre o hemograma de ovinos sadios da raça Santa Inês, criados na região de Piedade, no Estado de São Paulo. O hematócrito e o número de hemácias apresentaram maiores valores nas fêmeas mais jovens e houve um decréscimo gradual durante o desenvolvimento etário dos animais. Em contraposição, o número total de leucócitos foi menor nos animais mais jovens e apresentou elevação gradual com a evolução da idade dos animais.Influence of age and sex factors on blood count was investigated in healthy sheep of the Santa Ines breed, raised in the region of Piedade (São Paulo State). The hematocrit and red blood cell count presented higher values in younger females, and a gradual decrease occurred during animals’ ageing. In contrast, the total number of leukocytes was lower in younger animals and showed a gradual increase with their ageing.
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