1,745 research outputs found
Righteous Adam, Sinister Eve
Supplementary Materials (Appendix 1-3) for "Righteous Adam, Sinister Eve", by Sergio Della Sala & Robert D McIntosh
Real-Time Description of the Electronic Dynamics for a Molecule close to a Plasmonic Nanoparticle
The optical properties of molecules close to plasmonic nanostructures greatly
differ from their isolated molecule counterparts. To theoretically investigate
such systems in a Quantum Chemistry perspective, one has to take into account
that the plasmonic nanostructure (e.g., a metal nanoparticle - NP) is often too
large to be treated atomistically. Therefore, a multiscale description, where
the molecule is treated by an ab initio approach and the metal NP by a lower
level description, is needed. Here we present an extension of one such
multiscale model [Corni, S.; Tomasi, J. {\it J. Chem. Phys.} {\bf 2001}, {\it
114}, 3739] originally inspired by the Polarizable Continuum Model, to a
real-time description of the electronic dynamics of the molecule and of the NP.
In particular, we adopt a Time-Dependent Configuration Interaction (TD CI)
approach for the molecule, the metal NP is described as a continuous dielectric
of complex shape characterized by a Drude-Lorentz dielectric function and the
molecule- NP electromagnetic coupling is treated by an equation-of-motion (EOM)
extension of the quasi-static Boundary Element Method (BEM). The model includes
the effects of both the mutual molecule- NP time-dependent polarization and the
modification of the probing electromagnetic field due to the plasmonic
resonances of the NP. Finally, such an approach is applied to the investigation
of the light absorption of a model chromophore, LiCN, in the presence of a
metal NP of complex shape.Comment: This is the final peer-reviewed manuscript accepted for publication
of an open access article published under an ACS AuthorChoice License, which
permits copying and redistribution of the article or any adaptations for
non-commercial purposes. Link to the original article:
http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.6b1108
A novel automata-theoretic approach to timeline-based planning
Timeline-based planning is a well-established approach successfully employed
in a number of application domains. A very restricted fragment, featuring
only bounded temporal relations and token durations, is expressive enough to
capture action-based temporal planning. As for computational complexity, it has
been shown to be EXPSPACE-complete when unbounded temporal relations,
but only bounded token durations, are allowed.
In this paper, we present a novel automata-theoretic characterisation of
timeline-based planning where the existence of a plan is shown to be
equivalent to the nonemptiness of the language recognised by a
nondeterministic finite-state automaton that suitably encodes all the problem
constraints (timelines and synchronisation rules).
Besides allowing us to restate known complexity results in a fairly natural
and compact way, such an alternative characterisation makes it possible to
finally establish the exact complexity of the full version of the problem with
unbounded temporal relations and token durations, which was still open and turns out
to be EXPSPACE-complete.
Moreover, the proposed technique is general enough to cope with (infinite) recurrent goals,
which received little attention so far, despite being quite common in real-word
application scenarios
Decidability and complexity of the fragments of the modal logic of Allen's relations over the rationals
Interval temporal logics provide a natural framework for temporal
reasoning about interval structures over linearly
ordered domains, where intervals are taken as first-class
citizens. Their expressive power and computational behaviour
mainly depend on two parameters: the set of modalities they feature and
the linear orders over which they are interpreted. In this paper, we consider
all fragments of Halpern and Shoham's interval temporal logic hs
with a decidable satisfiability problem over the rationals,
and we provide a complete classification of them in
terms of their expressiveness and computational complexity by solving the last few
open problems
Skill and self-knowledge:Empirical refutation of the dual-burden account of the Dunning-Kruger effect
For many intellectual tasks, the people with the least skill overestimate themselves the most, a pattern popularly known as the DunningâKruger effect (DKE). The dominant account of this effect depends on the idea that assessing the quality of one's performance (metacognition) requires the same mental resources as task performance itself (cognition). Unskilled people are said to suffer a dual burden: they lack the cognitive resources to perform well, and this deprives them of metacognitive insight into their failings. In this Registered Report, we applied recently developed methods for the measurement of metacognition to a matrix reasoning task, to test the dual-burden account. Metacognitive sensitivity (information exploited by metacognition) tracked performance closely, so less information was exploited by the metacognitive judgements of poor performers; but metacognitive efficiency (quality of metacognitive processing itself) was unrelated to performance. Metacognitive bias (overall tendency towards high or low confidence) was positively associated with performance, so poor performers were appropriately less confidentânot more confidentâthan good performers. Crucially, these metacognitive factors did not cause the DKE pattern, which was driven overwhelmingly by performance scores. These results refute the dual-burden account and suggest that the classic DKE is a statistical regression artefact that tells us nothing much about metacognition
X-ray monitoring of classical novae in the central region of M31. III. Autumn and winter 2009/10, 2010/11 and 2011/12
[Abridged] Classical novae (CNe) represent the major class of supersoft X-ray
sources (SSSs) in the central region of our neighbouring galaxy M31. We
performed a dedicated monitoring of the M31 central region, aimed to detect SSS
counterparts of CNe, with XMM-Newton and Chandra between Nov and Mar of the
years 2009/10, 2010/11 and 2011/12. In total we detected 24 novae in X-rays.
Seven of these sources were known from previous observations, including the M31
nova with the longest SSS phase, M31N~1996-08b, which was found to fade below
our X-ray detection limit 13.8 yr after outburst. Of the new discoveries
several novae exhibit significant variability in their short-term X-ray light
curves with one object showing a suspected period of about 1.3 h. We studied
the SSS state of the most recent outburst of a recurrent nova which had
previously shown the shortest time ever observed between two outbursts (about 5
yr). The total number of M31 novae with X-ray counterpart was increased to 79
and we subjected this extended catalogue to detailed statistical studies. Four
previously indicated correlations between optical and X-ray parameters could be
confirmed and improved. We found indications that the multi-dimensional
parameter space of nova properties might be dominated by a single physical
parameter. We discuss evidence for a different X-ray behaviour of novae in the
M31 bulge and disk. Exploration of the multi-wavelength parameter space of
optical and X-ray measurements is shown to be a powerful tool for examining
properties of extragalactic nova populations. While there are hints that the
different stellar populations of M31 (bulge vs disk) produce dissimilar nova
outbursts, there is also growing evidence that the overall behaviour of an
average nova might be understood in surprisingly simple terms.Comment: 39 pages (half of them for 9 tables), 14 figures, accepted for
publication in A&A; updated after language editing stag
An Optimal Decision Procedure for MPNL over the Integers
Interval temporal logics provide a natural framework for qualitative and
quantitative temporal reason- ing over interval structures, where the truth of
formulae is defined over intervals rather than points. In this paper, we study
the complexity of the satisfiability problem for Metric Propositional Neigh-
borhood Logic (MPNL). MPNL features two modalities to access intervals "to the
left" and "to the right" of the current one, respectively, plus an infinite set
of length constraints. MPNL, interpreted over the naturals, has been recently
shown to be decidable by a doubly exponential procedure. We improve such a
result by proving that MPNL is actually EXPSPACE-complete (even when length
constraints are encoded in binary), when interpreted over finite structures,
the naturals, and the in- tegers, by developing an EXPSPACE decision procedure
for MPNL over the integers, which can be easily tailored to finite linear
orders and the naturals (EXPSPACE-hardness was already known).Comment: In Proceedings GandALF 2011, arXiv:1106.081
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