10,358 research outputs found
The internationalisation of the Spanish SME sector
As part of a wider research program, we analysed the theoretical framework and the recent developments of the process of internationalisation (transnationalisation) of the small- and medium-sized enterprises in Spain. The paper highlights the main trends and barriers of this internationalisation process. Methodology included document analyses, interviews, and the analyses of statistical databases
Zero-shot keyword spotting for visual speech recognition in-the-wild
Visual keyword spotting (KWS) is the problem of estimating whether a text
query occurs in a given recording using only video information. This paper
focuses on visual KWS for words unseen during training, a real-world, practical
setting which so far has received no attention by the community. To this end,
we devise an end-to-end architecture comprising (a) a state-of-the-art visual
feature extractor based on spatiotemporal Residual Networks, (b) a
grapheme-to-phoneme model based on sequence-to-sequence neural networks, and
(c) a stack of recurrent neural networks which learn how to correlate visual
features with the keyword representation. Different to prior works on KWS,
which try to learn word representations merely from sequences of graphemes
(i.e. letters), we propose the use of a grapheme-to-phoneme encoder-decoder
model which learns how to map words to their pronunciation. We demonstrate that
our system obtains very promising visual-only KWS results on the challenging
LRS2 database, for keywords unseen during training. We also show that our
system outperforms a baseline which addresses KWS via automatic speech
recognition (ASR), while it drastically improves over other recently proposed
ASR-free KWS methods.Comment: Accepted at ECCV-201
Unexpected impact of D waves in low-energy neutral pion photoproduction from the proton and the extraction of multipoles
Contributions of waves to physical observables for neutral pion
photoproduction from the proton in the near-threshold region are studied and
means to isolate them are proposed. Various approaches to describe the
multipoles are employed
--a phenomenological one, a unitary one, and heavy baryon chiral perturbation
theory. The results of these approaches are compared and found to yield
essentially the same answers. waves are seen to enter together with
waves in a way that any means which attempt to obtain the multipole
accurately must rely on knowledge of waves and that consequently the latter
cannot be dismissed in analyses of low-energy pion photoproduction. It is shown
that waves have a significant impact on double-polarization observables
that can be measured. This importance of waves is due to the soft nature of
the wave and is a direct consequence of chiral symmetry and the
Nambu--Goldstone nature of the pion. -wave contributions are shown to be
negligible in the near-threshold region.Comment: 38 pages, 13 figures, 19 tables. Version to be published in Physical
Review
Testing the role of mate recognition proteins in a incipient ecological spreciation process
Comunicaciones a congreso
Alarm-Based Prescriptive Process Monitoring
Predictive process monitoring is concerned with the analysis of events
produced during the execution of a process in order to predict the future state
of ongoing cases thereof. Existing techniques in this field are able to
predict, at each step of a case, the likelihood that the case will end up in an
undesired outcome. These techniques, however, do not take into account what
process workers may do with the generated predictions in order to decrease the
likelihood of undesired outcomes. This paper proposes a framework for
prescriptive process monitoring, which extends predictive process monitoring
approaches with the concepts of alarms, interventions, compensations, and
mitigation effects. The framework incorporates a parameterized cost model to
assess the cost-benefit tradeoffs of applying prescriptive process monitoring
in a given setting. The paper also outlines an approach to optimize the
generation of alarms given a dataset and a set of cost model parameters. The
proposed approach is empirically evaluated using a range of real-life event
logs
Kyoto and Mañana: A CGE analysis of Spanish Greenhouse Gas targets to 2020
Employing a recursive dynamic computable general equilibrium (CGE) model of the Spanish economy, this study explicitly aims to characterise the potential impact of Kyoto and European Union environmental policy targets on the Spanish economy up to 2020, with a particular focus on the agricultural sector. The model code is modified to characterise the emissions trading scheme (ETS), emissions quotas and carbon taxes, whilst emissions reductions are applied to all six registered greenhouse gases (GHGs). As extensions to this work, the study attempts to integrate both the use of ‘Marginal Abatement Cost’ (MAC) curves for potential emissions reductions within the agricultural sector, and econometric estimates of the effects of global warming on land productivity in Spain.
The study includes a no action baseline (with 2007 as the benchmark year), in which GHGs are not restricted in any sector of the economy. This is compared to an emissions stabilisation scenario, in which the European Union’s Emissions Trading Scheme (EU ETS) is implemented, and all of Spain’s commitments under Kyoto, and various pieces of EU climate change legislation, are met. Under this scenario, the policy-induced price rises of polluting inputs and processes determines the allocation of emissions reductions amongst the various industries in the economy.
Given the agricultural focus of the study, the modelling of emissions response in this sector is further enhanced by the inclusion of MAC curves. These map out an endogenous technological response to price rises, and the extent to which the emissions coefficient (e.g. N2O per Kg of fertiliser applied, or CH4 per head of cattle) can be reduced, such that the same quantity of input emits a smaller amount of GHGs. A flexible functional form is used to calibrate the MAC curves to data from the IIASAs GAINS model , which includes potential emissions reductions, and associated costs, of all major technological advances in agriculture currently ...Publishe
Geometric phases for neutral and charged particles in a time-dependent magnetic field
It is well known that any cyclic solution of a spin 1/2 neutral particle
moving in an arbitrary magnetic field has a nonadiabatic geometric phase
proportional to the solid angle subtended by the trace of the spin. For neutral
particles with higher spin, this is true for cyclic solutions with special
initial conditions. For more general cyclic solutions, however, this does not
hold. As an example, we consider the most general solutions of such particles
moving in a rotating magnetic field. If the parameters of the system are
appropriately chosen, all solutions are cyclic. The nonadiabatic geometric
phase and the solid angle are both calculated explicitly. It turns out that the
nonadiabatic geometric phase contains an extra term in addition to the one
proportional to the solid angle. The extra term vanishes automatically for spin
1/2. For higher spin, however, it depends on the initial condition. We also
consider the valence electron of an alkaline atom. For cyclic solutions with
special initial conditions in an arbitrary strong magnetic field, we prove that
the nonadiabatic geometric phase is a linear combination of the two solid
angles subtended by the traces of the orbit and spin angular momenta. For more
general cyclic solutions in a strong rotating magnetic field, the nonadiabatic
geometric phase also contains extra terms in addition to the linear
combination.Comment: revtex, 18 pages, no figur
Exactly Solvable Hydrogen-like Potentials and Factorization Method
A set of factorization energies is introduced, giving rise to a
generalization of the Schr\"{o}dinger (or Infeld and Hull) factorization for
the radial hydrogen-like Hamiltonian. An algebraic intertwining technique
involving such factorization energies leads to derive -parametric families
of potentials in general almost-isospectral to the hydrogen-like radial
Hamiltonians. The construction of SUSY partner Hamiltonians with ground state
energies greater than the corresponding ground state energy of the initial
Hamiltonian is also explicitly performed.Comment: LaTex file, 21 pages, 2 PostScript figures and some references added.
To be published in J. Phys. A: Math. Gen. (1998
Spin degree of freedom in two dimensional exciton condensates
We present a theoretical analysis of a spin-dependent multicomponent
condensate in two dimensions. The case of a condensate of resonantly
photoexcited excitons having two different spin orientations is studied in
detail. The energy and the chemical potentials of this system depend strongly
on the spin polarization . When electrons and holes are located in two
different planes, the condensate can be either totally spin polarized or spin
unpolarized, a property that is measurable. The phase diagram in terms of the
total density and electron-hole separation is discussed.Comment: 4 pages, 3 figures, Accepted for publication in Physical Review
Letter
Subfunctionalization reduces the fitness cost of gene duplication in humans by buffering dosage imbalances
<p>Abstract</p> <p>Background</p> <p>Driven essentially by random genetic drift, subfunctionalization has been identified as a possible non-adaptive mechanism for the retention of duplicate genes in small-population species, where widespread deleterious mutations are likely to cause complementary loss of subfunctions across gene copies. Through subfunctionalization, duplicates become indispensable to maintain the functional requirements of the ancestral locus. Yet, gene duplication produces a dosage imbalance in the encoded proteins and thus, as investigated in this paper, subfunctionalization must be subject to the selective forces arising from the fitness bottleneck introduced by the duplication event.</p> <p>Results</p> <p>We show that, while arising from random drift, subfunctionalization must be inescapably subject to selective forces, since the diversification of expression patterns across paralogs mitigates duplication-related dosage imbalances in the concentrations of encoded proteins. Dosage imbalance effects become paramount when proteins rely on obligatory associations to maintain their structural integrity, and are expected to be weaker when protein complexation is ephemeral or adventitious. To establish the buffering effect of subfunctionalization on selection pressure, we determine the packing quality of encoded proteins, an established indicator of dosage sensitivity, and correlate this parameter with the extent of paralog segregation in humans, using species with larger population -and more efficient selection- as controls.</p> <p>Conclusions</p> <p>Recognizing the role of subfunctionalization as a dosage-imbalance buffer in gene duplication events enabled us to reconcile its mechanistic nonadaptive origin with its adaptive role as an enabler of the evolution of genetic redundancy. This constructive role was established in this paper by proving the following assertion: <it>If subfunctionalization is indeed adaptive, its effect on paralog segregation should scale with the dosage sensitivity of the duplicated genes</it>. Thus, subfunctionalization becomes adaptive in response to the selection forces arising from the fitness bottleneck imposed by gene duplication.</p
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