529 research outputs found
Understanding decision quality through satisfaction
"PAAMS 2014 International Workshops, Salamanca, Spain, June 4-6, 2014. Proceedings"One of the most important factors to determine the success of an or-ganization is the quality of decisions made. In order to improve the decisions taken and to strengthen the competitiveness of organizations, systems such as Group Decision Support Systems (GDSSs) have been strongly developed and studied in recent decades. The amount of GDSSs incorporating automatic nego-tiation mechanisms, such as argumentation, is increasing nowadays. The evalu-ation of these mechanisms and the understanding of their real benefits for the organizations is still a hard challenge. In this article, we propose a model that allows a GDSS to measure the participant’s satisfaction with the decision, con-sidering aspects such as problem evaluation, personality, emotions and expecta-tions. This model is intended to enable the understanding of the decision’s qual-ity achieved with an argumentation system and to evaluate its capability to po-tentiate the decision’s quality. The proposed model validates all the assump-tions found in the literature regarding the participant’s satisfaction.This work is supported by FEDER Funds through the “Programa Operacional Fac-tores de Competitividade - COMPETE” program and by National Funds through FCT “Fundação para a Ciência e a Tecnologia” under the project: FCOMP-01-0124-FEDER-PEst-OE/EEI/UI0760/2011 and SFRH/BD/89697/2012
Ownership and control in a competitive industry
We study a differentiated product market in which an investor initially owns a controlling stake in one of two competing firms and may acquire a non-controlling or a controlling stake in a competitor, either directly using her own assets, or indirectly via the controlled firm. While industry profits are maximized within a symmetric two product monopoly, the investor attains this only in exceptional cases. Instead, she sometimes acquires a noncontrolling stake. Or she invests asymmetrically rather than pursuing a full takeover if she acquires a controlling one. Generally, she invests indirectly if she only wants to affect the product market outcome, and directly if acquiring shares is profitable per se. --differentiated products,separation of ownership and control,private benefits of control
Angular momentum exchange during secular migration of two-planet systems
We investigate the secular dynamics of two-planet coplanar systems evolving
under mutual gravitational interactions and dissipative forces. We consider two
mechanisms responsible for the planetary migration: star-planet (or
planet-satellite) tidal interactions and interactions of a planet with a
gaseous disc. We show that each migration mechanism is characterized by a
specific law of orbital angular momentum exchange. Calculating stationary
solutions of the conservative secular problem and taking into account the
orbital angular momentum leakage, we trace the evolutionary routes followed by
the planet pairs during the migration process. This procedure allows us to
recover the dynamical history of two-planet systems and constrain parameters of
the involved physical processes.Comment: 20 pages, 9 figures, accepted for publication in Celestial Mechanics
and Dynamical Astronomy (special issue on Exoplanets
Cell membrane damage induced by phenolic acids on wine lactic acid bacteria
The aim of this work was to investigate the effect of phenolic acids on cell membrane permeability of
lactic acid bacteria from wine. Several phenolic acids were tested for their effects on the cell membrane of
Oenococcus oeni and Lactobacillus hilgardii by measuring potassium and phosphate efflux, proton influx and
by assessing culture viability employing a fluorescence technique based on membrane integrity. The
experimental results indicate that hydroxycinnamic acids (p-coumaric, caffeic and ferulic acids) induce
greater ion leakages and higher proton influx than hydroxybenzoic acids (p-hydroxibenzoic, protocatechuic,
gallic, vanillic, and syringic acids). Among the hydroxycinnamic acids, p-coumaric acid showed the strongest
effect. Moreover, the exposure of cells to phenolic acids caused a significant decrease in cell culture viability,
as measured by the fluorescence assay, in both tested strains. The results agree with previous results
obtained in growth experiments with the same strains. Generally, phenolic acids increased the cell
membrane permeability in lactic acid bacteria from wine. The different effects of phenolic acids on
membrane permeability could be related to differences in their structure and lipophilic character
Inferring Loop Invariants using Postconditions
One of the obstacles in automatic program proving is to obtain suitable loop
invariants.
The invariant of a loop is a weakened form of its postcondition (the loop's
goal, also known as its contract); the present work takes advantage of this
observation by using the postcondition as the basis for invariant inference,
using various heuristics such as "uncoupling" which prove useful in many
important algorithms.
Thanks to these heuristics, the technique is able to infer invariants for a
large variety of loop examples.
We present the theory behind the technique, its implementation (freely
available for download and currently relying on Microsoft Research's Boogie
tool), and the results obtained.Comment: Slightly revised versio
Asymptotic behaviour of the gluon propagator from lattice QCD
We study the flavorless gluon propagator in the Landau gauge from high
statistics lattice calculations. Hypercubic artifacts are efficiently
eliminated by taking the limit. The propagator is fitted
to the three-loops perturbative formula in an energy window ranging form
2.5 GeV up to 5.5 GeV. is extracted from the best fit in a
continuous set of renormalisation schemes. The fits are very good, with a
per d.o.f smaller than 1. We propose a more stringent test of
asymptotic scaling based on scheme independence of the resulting . This method shows that asymptotic scaling at three loops is not reached
by the gluon propagator although we use rather large energies. We are only able
to obtain an effective flavorless three-loops estimate MeV. We argue that the real asymptotic
value for should plausibly be smaller.Comment: 16 pages, 9 figures, revTe
Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory
Data from the Pierre Auger Observatory are analyzed to search for
anisotropies near the direction of the Galactic Centre at EeV energies. The
exposure of the surface array in this part of the sky is already significantly
larger than that of the fore-runner experiments. Our results do not support
previous findings of localized excesses in the AGASA and SUGAR data. We set an
upper bound on a point-like flux of cosmic rays arriving from the Galactic
Centre which excludes several scenarios predicting sources of EeV neutrons from
Sagittarius . Also the events detected simultaneously by the surface and
fluorescence detectors (the `hybrid' data set), which have better pointing
accuracy but are less numerous than those of the surface array alone, do not
show any significant localized excess from this direction.Comment: Matches published versio
Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum
We report a first measurement for ultra-high energy cosmic rays of the
correlation between the depth of shower maximum and the signal in the water
Cherenkov stations of air-showers registered simultaneously by the fluorescence
and the surface detectors of the Pierre Auger Observatory. Such a correlation
measurement is a unique feature of a hybrid air-shower observatory with
sensitivity to both the electromagnetic and muonic components. It allows an
accurate determination of the spread of primary masses in the cosmic-ray flux.
Up till now, constraints on the spread of primary masses have been dominated by
systematic uncertainties. The present correlation measurement is not affected
by systematics in the measurement of the depth of shower maximum or the signal
in the water Cherenkov stations. The analysis relies on general characteristics
of air showers and is thus robust also with respect to uncertainties in
hadronic event generators. The observed correlation in the energy range around
the `ankle' at differs significantly from
expectations for pure primary cosmic-ray compositions. A light composition made
up of proton and helium only is equally inconsistent with observations. The
data are explained well by a mixed composition including nuclei with mass . Scenarios such as the proton dip model, with almost pure compositions, are
thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray
flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report
Numbe
DRP1 levels determine the apoptotic threshold during embryonic differentiation through a mitophagy-dependent mechanism.
The changes that drive differentiation facilitate the emergence of abnormal cells that need to be removed before they contribute to further development or the germline. Consequently, in mice in the lead-up to gastrulation, ∼35% of embryonic cells are eliminated. This elimination is caused by hypersensitivity to apoptosis, but how it is regulated is poorly understood. Here, we show that upon exit of naive pluripotency, mouse embryonic stem cells lower their mitochondrial apoptotic threshold, and this increases their sensitivity to cell death. We demonstrate that this enhanced apoptotic response is induced by a decrease in mitochondrial fission due to a reduction in the activity of dynamin-related protein 1 (DRP1). Furthermore, we show that in naive pluripotent cells, DRP1 prevents apoptosis by promoting mitophagy. In contrast, during differentiation, reduced mitophagy levels facilitate apoptosis. Together, these results indicate that during early mammalian development, DRP1 regulation of mitophagy determines the apoptotic response
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
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