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Modelling the developmental patterning of finiteness marking in English, Dutch, German and Spanish using MOSAIC
In this paper we apply MOSAIC (Model of Syntax Acquisition in Children) to the simulation of the developmental patterning of children’s Optional Infinitive (OI) errors in four languages: English, Dutch, German and Spanish. MOSAIC, which has already simulated this phenomenon in Dutch and English, now implements a learning mechanism that better reflects the theoretical assumptions underlying it, as well as a chunking mechanism which results in frequent phrases being treated as one unit. Using one, identical model that learns from child-directed speech, we obtain a close quantitative fit to the data from all four languages, despite there being considerable cross-linguistic and developmental variation in the OI phenomenon. MOSAIC successfully simulates the difference between Spanish (a pro-drop language where OI errors are virtually absent), and Obligatory Subject languages that do display the OI phenomenon. It also highlights differences in the OI phenomenon across German and Dutch, two closely related languages whose grammar is virtually identical with respect to the relation between finiteness and verb placement. Taken together, these results suggest that (a) cross-linguistic differences in the rates at which children produce Optional Infinitives are graded, quantitative differences that closely reflect the statistical properties of the input they are exposed to and (b) theories of syntax acquisition need to consider more closely the role of input characteristics as determinants of quantitative differences in the cross-linguistic patterning of phenomena in language acquisition
DMRG Simulation of the SU(3) AFM Heisenberg Model
We analyze the antiferromagnetic Heisenberg chain by means of
the Density Matrix Renormalization Group (DMRG). The results confirm that the
model is critical and the computation of its central charge and the scaling
dimensions of the first excited states show that the underlying low energy
conformal field theory is the Wess-Zumino-Novikov-Witten
model.Comment: corrections and improvements adde
Non-hermitian topology as a unifying framework for the Andreev versus Majorana states controversy
Zero-energy Andreev levels in hybrid semiconductor-superconductor nanowires mimic all expected Majorana phenomenology, including 2 e2∕ h conductance quantisation, even where band topology predicts trivial phases. This surprising fact has been used to challenge the interpretation of various transport experiments in terms of Majorana zero modes. Here we show that the Andreev versus Majorana controversy is clarified when framed in the language of non-Hermitian topology, the natural description for quantum systems open to the environment. This change of paradigm allows one to understand topological transitions and the emergence of zero modes in more general systems than can be described by band topology. This is achieved by studying exceptional point bifurcations in the complex spectrum of the system’s non-Hermitian Hamiltonian. Within this broader topological classification, Majoranas from both conventional band topology and a large subset of Andreev levels at zero energy are in fact topologically equivalent, which explains why they cannot be distinguishedWe thank J. Cayao for useful discussions in the early stages of this work. Research supported by the Spanish Ministry of Science, Innovation and Universities through Grants PGC2018-097018-B-I00, FIS2015-65706-P, FIS2015-64654-P, FIS2016-80434-P (AEI/FEDER, EU), the FPI programme BES-2016-078122, the Ramón y Cajal programme Grants RYC-2011-09345, RYC-2013-14645, the María de Maeztu Programme for Units of Excellence in R&D (MDM-2014-0377), and the European Union’s Horizon 2020 research and innovation programme under the FETOPEN Grant Agreement No. 828948. We also acknowledge support from CSIC Research Platform on Quantum Technologies PTI-00
Mapping Kitaev's quantum double lattice models to Levin and Wen's string-net models
We exhibit a mapping identifying Kitaev's quantum double lattice models
explicitly as a subclass of Levin and Wen's string net models via a completion
of the local Hilbert spaces with auxiliary degrees of freedom. This
identification allows to carry over to these string net models the
representation-theoretic classification of the excitations in quantum double
models, as well as define them in arbitrary lattices, and provides an
illustration of the abstract notion of Morita equivalence. The possibility of
generalising the map to broader classes of string nets is considered.Comment: 8 pages, 6 eps figures; v2: matches published versio
Majorana Zero Modes in Graphene
A clear demonstration of topological superconductivity (TS) and Majorana zero
modes remains one of the major pending goal in the field of topological
materials. One common strategy to generate TS is through the coupling of an
s-wave superconductor to a helical half-metallic system. Numerous proposals for
the latter have been put forward in the literature, most of them based on
semiconductors or topological insulators with strong spin-orbit coupling. Here
we demonstrate an alternative approach for the creation of TS in
graphene/superconductor junctions without the need of spin-orbit coupling. Our
prediction stems from the helicity of graphene's zero Landau level edge states
in the presence of interactions, and on the possibility, experimentally
demonstrated, to tune their magnetic properties with in-plane magnetic fields.
We show how canted antiferromagnetic ordering in the graphene bulk close to
neutrality induces TS along the junction, and gives rise to isolated,
topologically protected Majorana bound states at either end. We also discuss
possible strategies to detect their presence in graphene Josephson junctions
through Fraunhofer pattern anomalies and Andreev spectroscopy. The latter in
particular exhibits strong unambiguous signatures of the presence of the
Majorana states in the form of universal zero bias anomalies. Remarkable
progress has recently been reported in the fabrication of the proposed type of
junctions, which offers a promising outlook for Majorana physics in graphene
systems.Comment: 14 pages, 8 figures. Included simulations of Andreev spectroscopy and
mor
La responsabilidad de entender y el deber de hacerse entender: el texto reglamentario como diálogo entre normadores y normados
En el ámbito de los textos de ingeniería civil existen diferentes géneros, con sus correspondientes características. Uno de esos tipos es el que se centra en la reglamentación técnica. ..
Decision-making through Sustainability
From immemorial time, dams have contributed significantly for the progress of civilizations. For this reason, nowadays, there is a vast engineering heritage. Over the years, these infrastructures can present some ordinary maintenance issues associated with their normal operation or with ageing processes.
Normally, these problems do not represent an important risk for the structure, but they have to be attended. To do it, owners of dams have to finance many ordinary interventions. As it is impossible to carry out all of them at the same time, managers have to make a decision and select the most “important” ones. However, it is not easy because interventions usually have very different natures (for example: repair a bottom outlet, change gates, seal a crack...) and because they cannot use a classical risk analysis for these type of interventions.
Authors, who are aware this problem, present, in this paper, a multi-criteria decision-making system to prioritize these interventions with the aim of providing engineers a useful tool, with which they can order the interventions from the most important to the last. To do it, authors have used MIVES. This tool defines the Prioritization Index for the Management of Hydraulic Structures (PIMHS), which assesses, in two indivisible phases, the contribution to sustainability of each intervention. The first phase measures the damage of the dam, and the second one measures the social, environmental and economic impacts. At the end of the paper, it is presented a case of study where some interventions are evaluated with PIMHS
The puzzling interpretation of NIR indices: The case of NaI2.21
We present a detailed study of the Na I line strength index centered in the
-band at , {\AA} (NaI2.21 hereafter) relying on different samples of
early-type galaxies. Consistent with previous studies, we find that the
observed line strength indices cannot be fit by state-of-art scaled-solar
stellar population models, even using our newly developed models in the NIR.
The models clearly underestimate the large NaI2.21 values measured for most
early-type galaxies. However, we develop a Na-enhanced version of our newly
developed models in the NIR, which - together with the effect of a bottom-heavy
initial mass function - yield NaI2.21 indices in the range of the observations.
Therefore, we suggest a scenario in which the combined effect of [Na/Fe]
enhancement and a bottom-heavy initial mass function are mainly responsible for
the large NaI2.21 indices observed for most early-type galaxies. To a smaller
extent, also [C/Fe] enhancement might contribute to the large observed NaI2.21
values.Comment: 13 pages, 4 figures, accepted for publication in MNRA
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