154 research outputs found
Muonium avoided level crossing measurement of electron spin relaxation rate in a series of substituted anthradithiophene based molecules
Muon spin spectroscopy and in particular the avoided level crossing technique is introduced, with the aim of showing it as a very sensitive local probe for electron spin relaxation in organic semiconductors. Avoided level crossing data on tert-butyl-ethynyl anthradithiophene, tri-methyl-silyl-ethynyl anthradithiophene and tri-ethygermyl-ethynyl anthradithiophene at different temperatures are presented. This series of molecules have an identical anthradithiophene backbone, but we have performed a targeted substitution on the central atom of the two side groups, of C, Si and Ge. We extracted the electron spin relaxation for the three molecules of this series and discuss them in the context of previously published results
Chemical freeze-out temperature in hydrodynamical description of Au+Au collisions at sqrt(s_NN) = 200 GeV
We study the effect of separate chemical and kinetic freeze-outs to the ideal
hydrodynamical flow in Au+Au collisions at RHIC (sqrt(s_NN) = 200 GeV energy).
Unlike in earlier studies we explore how these effects can be counteracted by
changes in the initial state of the hydrodynamical evolution. We conclude that
the reproduction of pion, proton and antiproton yields necessitates a chemical
freeze-out temperature of T = 150 MeV instead of T = 160 - 170 MeV motivated by
thermal models. Unlike previously reported, this lower temperature makes it
possible to reproduce the p_T-spectra of hadrons if one assumes very small
initial time, tau_0 = 0.2 fm/c. However, the p_T-differential elliptic flow,
v_2(p_T) remains badly reproduced. This points to the need to include
dissipative effects (viscosity) or some other refinement to the model.Comment: 8 pages, 7 figures; Accepted for publication in European Physical
Journal A; Added discussion about the effect of weak decays to chemical
freeze-out temperature and a figure showing isentropic curves in T-mu plan
Personal identity (de)formation among lifestyle travellers: A double-edged sword?
This article explores the personal identity work of lifestyle travellers â individuals for whom extended leisure travel is a preferred lifestyle that they return to repeatedly. Qualitative findings from in-depth semi-structured interviews with lifestyle travellers in northern India and southern Thailand are interpreted in light of theories on identity formation in late modernity that position identity as problematic. It is suggested that extended leisure travel can provide exposure to varied cultural praxes that may contribute to a sense of social saturation. Whilst a minority of the respondents embraced a saturation of personal identity in the subjective formation of a cosmopolitan cultural identity, several of the respondents were paradoxically left with more identity questions than answers as the result of their travels
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Relationships Between Archimedean Copulas and Morgenstern Utility Functions
The (additive) generator of an Archimedean copula is a strictly decreasing and convexfunction, while Morgenstern utility functions (applying to risk aversion decision makers) arenondecreasing and concave. In this presentation, relationships between generators and utilityfunctions are established. For some well known Archimedean copula families, links betweenthe generator and the corresponding utility function are demonstrated.Some new copulafamilies are derived from classes of utility functions which appeared in the literature, andtheir properties are discussed. It is shown how dependence properties of an Archimedeancopula translate into properties of the utility function from whichthey are constructed
How brains make decisions
This chapter, dedicated to the memory of Mino Freund, summarizes the Quantum
Decision Theory (QDT) that we have developed in a series of publications since
2008. We formulate a general mathematical scheme of how decisions are taken,
using the point of view of psychological and cognitive sciences, without
touching physiological aspects. The basic principles of how intelligence acts
are discussed. The human brain processes involved in decisions are argued to be
principally different from straightforward computer operations. The difference
lies in the conscious-subconscious duality of the decision making process and
the role of emotions that compete with utility optimization. The most general
approach for characterizing the process of decision making, taking into account
the conscious-subconscious duality, uses the framework of functional analysis
in Hilbert spaces, similarly to that used in the quantum theory of
measurements. This does not imply that the brain is a quantum system, but just
allows for the simplest and most general extension of classical decision
theory. The resulting theory of quantum decision making, based on the rules of
quantum measurements, solves all paradoxes of classical decision making,
allowing for quantitative predictions that are in excellent agreement with
experiments. Finally, we provide a novel application by comparing the
predictions of QDT with experiments on the prisoner dilemma game. The developed
theory can serve as a guide for creating artificial intelligence acting by
quantum rules.Comment: Latex file, 20 pages, 3 figure
Last Call for RHIC Predictions
This paper contains the individual contributions of all speakers of the
session on 'Last Call for RHIC Predictions' at Quark Matter 99, and a summary
by the convenor.Comment: 56 pages, psfig, epsf, epsfig, graphicx style files required,
Proceedings of the XIV Int. Conf. on Nucleus-Nucleus Collisions, Quark Matter
99, Torino, Italy, May 10 - 15, 1999. Typographical mistakes corrected and
figure numbers change
Adsorption of mono- and multivalent cat- and anions on DNA molecules
Adsorption of monovalent and multivalent cat- and anions on a deoxyribose
nucleic acid (DNA) molecule from a salt solution is investigated by computer
simulation. The ions are modelled as charged hard spheres, the DNA molecule as
a point charge pattern following the double-helical phosphate strands. The
geometrical shape of the DNA molecules is modelled on different levels ranging
from a simple cylindrical shape to structured models which include the major
and minor grooves between the phosphate strands. The densities of the ions
adsorbed on the phosphate strands, in the major and in the minor grooves are
calculated. First, we find that the adsorption pattern on the DNA surface
depends strongly on its geometrical shape: counterions adsorb preferentially
along the phosphate strands for a cylindrical model shape, but in the minor
groove for a geometrically structured model. Second, we find that an addition
of monovalent salt ions results in an increase of the charge density in the
minor groove while the total charge density of ions adsorbed in the major
groove stays unchanged. The adsorbed ion densities are highly structured along
the minor groove while they are almost smeared along the major groove.
Furthermore, for a fixed amount of added salt, the major groove cationic charge
is independent on the counterion valency. For increasing salt concentration the
major groove is neutralized while the total charge adsorbed in the minor groove
is constant. DNA overcharging is detected for multivalent salt. Simulations for
a larger ion radii, which mimic the effect of the ion hydration, indicate an
increased adsorbtion of cations in the major groove.Comment: 34 pages with 14 figure
Early collective expansion: Relativistic hydrodynamics and the transport properties of QCD matter
Relativistic hydrodynamics for ideal and viscous fluids is discussed as a
tool to describe relativistic heavy-ion collisions and to extract transport
properties of the quark-gluon plasma from experimentally measured hadron
momentum spectra.Comment: Review article, 54 pages, 25 figure
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