bluuebunny/crossref_metadata_2025_split huggingface dataset:
A fault detection framework using recurrent neural networks for condition monitoring of wind turbines
Authors: Cui Yue , Bangalore Pramod , Bertling Tjernberg Lina 
Published: February 2021

AbstractThis paper proposes a fault detection framework for the condition monitoring of wind turbines. The framework models and analyzes the data in supervisory control and data acquisition systems. For log information, each event is mapped to an assembly based on the Reliawind taxonomy. For operation data, recurrent neural networks are applied to model normal behaviors, which can learn the long‐time temporal dependencies between various time series. Based on the estimation results, a two‐stage threshold method is proposed to determine the current operation status. The method evaluates the shift values deviating from the estimated behaviors and their duration time to attenuate the effect of minor fluctuations. The generated results from the framework can help to understand when the turbine deviates from normal operations. The framework is validated with the data from an onshore wind park. The numerical results show that the framework can detect operational risks and reduce false alarms.
Charged complexity and the thermofield double state
Authors: Chapman Shira , Chen Hong Zhe (Vincent) 
Published: February 2021

Abstract
We establish a systematic framework for studying quantum computational complexity of Gaussian states of charged systems based on Nielsen’s geometric approach. We use this framework to examine the effect of a chemical potential on the dynamics of complexity. As an example, we consider the complexity of a charged thermofield double state constructed from two free massive complex scalar fields in the presence of a chemical potential. We show that this state factorizes between positively and negatively charged modes and demonstrate that this fact can be used to relate it, for each momentum mode separately, to two uncharged thermofield double states with shifted temperatures and times. We evaluate the complexity of formation for the charged thermofield double state, both numerically and in certain analytic expansions. We further present numerical results for the time dependence of complexity. We compare various aspects of these results to those obtained in holography for charged black holes.
Nonrelativistic near-BPS corners of $$ \mathcal{N} $$ = 4 super-Yang-Mills with SU(1, 1) symmetry
Authors: Baiguera Stefano , Harmark Troels , Wintergerst Nico 
Published: February 2021

Abstract
We consider limits of $$ \mathcal{N} $$
N
= 4 super Yang-Mills (SYM) theory that approach BPS bounds and for which an SU(1,1) structure is preserved. The resulting near-BPS theories become non-relativistic, with a U(1) symmetry emerging in the limit that implies the conservation of particle number. They are obtained by reducing $$ \mathcal{N} $$
N
= 4 SYM on a three-sphere and subsequently integrating out fields that become non-dynamical as the bounds are approached. Upon quantization, and taking into account normal-ordering, they are consistent with taking the appropriate limits of the dilatation operator directly, thereby corresponding to Spin Matrix theories, found previously in the literature. In the particular case of the SU(1,1—1) near-BPS/Spin Matrix theory, we find a superfield formulation that applies to the full interacting theory. Moreover, for all the theories we find tantalizingly simple semi-local formulations as theories living on a circle. Finally, we find positive-definite expressions for the interactions in the classical limit for all the theories, which can be used to explore their strong coupling limits. This paper will have a companion paper in which we explore BPS bounds for which a SU(2,1) structure is preserved.
Recursive construction of the operator product expansion in curved space
Authors: Fröb Markus B. 
Published: February 2021

Abstract
I derive a formula for the coupling-constant derivative of the coefficients of the operator product expansion (Wilson OPE coefficients) in an arbitrary curved space, as the natural extension of the quantum action principle. Expanding the coefficients themselves in powers of the coupling constants, this formula allows to compute them recursively to arbitrary order. As input, only the OPE coefficients in the free theory are needed, which are easily obtained using Wick’s theorem. I illustrate the method by computing the OPE of two scalars ϕ in hyperbolic space (Euclidean Anti-de Sitter space) up to terms vanishing faster than the square of their separation to first order in the quartic interaction gϕ4, as well as the OPE coefficient "Image missing" at second order in g.
Closed string disk amplitudes in the pure spinor formalism
Authors: Bischof Andreas , Haack Michael 
Published: February 2021

Abstract
We evaluate closed string disk amplitudes in the pure spinor formalism. We focus on low point functions (two- and one-point functions) but our analysis is also relevant for higher n-point functions. Amongst others we discuss issues arising due to the gauge fixing of the conformal Killing group of the disk and due to the zero mode prescription in the pure spinor formalism. As expected, in the end we find agreement with the known results from the RNS formalism.
Pole skipping away from maximal chaos
Authors: Choi Changha , Mezei Márk , Sárosi Gábor 
Published: February 2021

AbstractPole skipping is a recently discovered subtle effect in the thermal energy density retarded two point function at a special point in the complex (ω, p) planes. We propose that pole skipping is determined by the stress tensor contribution to many-body chaos, and the special point is at (ω, p)p.s.=$$ i{\lambda}^{(T)}\left(1,1/{u}_B^{(T)}\right) $$iλT11/uBT, whereλ(T)= 2π/βand$$ {u}_B^{(T)} $$uBTare the stress tensor contributions to the Lyapunov exponent and the butterfly velocity respectively. While this proposal is consistent with previous studies conducted for maximally chaotic theories, where the stress tensor dominates chaos, it clarifies that one cannot use pole skipping to extract the Lyapunov exponent of a theory, which obeysλ≤λ(T). On the other hand, in a large class of strongly coupled but non-maximally chaotic theories$$ {u}_B^{(T)} $$uBTis the true butterfly velocity and we conjecture thatuB≤$$ {u}_B^{(T)} $$uBTis a universal bound. While it remains a challenge to explain pole skipping in a general framework, we provide a stringent test of our proposal in the large-qlimit of the SYK chain, where we determineλ, uB, and the energy density two point function in closed form for all values of the coupling, interpolating between the free and maximally chaotic limits. Since such an explicit expression for a thermal correlator is one of a kind, we take the opportunity to analyze many of its properties: the coupling dependence of the diffusion constant, the dispersion relations of poles, and the convergence properties of all order hydrodynamics.
Supersymmetry anomaly in the superconformal Wess-Zumino model
Authors: Katsianis Georgios , Papadimitriou Ioannis , Skenderis Kostas , Taylor Marika 
Published: February 2021

Abstract
We present a comprehensive analysis of supersymmetry anomalies in the free and massless Wess-Zumino (WZ) model in perturbation theory. At the classical level the model possesses $$ \mathcal{N} $$
N
= 1 superconformal symmetry, which is partially broken by quantum anomalies. The form of the anomalies and the part of the symmetry they break depend on the multiplet of conserved currents used. It was previously shown that the R-symmetry anomaly of the conformal current multiplet induces an anomaly in Q-supersymmetry, which appears first in 4-point functions. Here we confirm this result by an explicit 1-loop computation using a supersymmetric Pauli-Villars regulator.The conformal current multiplet does not exist in the regulated theory because the regulator breaks conformal invariance, R-symmetry and S-supersymmetry explicitly. The minimal massive multiplet is the Ferrara-Zumino (FZ) one and the supersymmetry preserved by the regulator is a specific field dependent combination of Q- and S- supersymmetry of the conformal multiplet. While this supersymmetry is non anomalous, conformal invariance, R-symmetry and the original Q- and S-supersymmetries are explicitly broken by finite contact terms, both in the regulated and renormalized theories.A conformal current multiplet does exist for the renormalized theory and may be obtained from the FZ multiplet by a set of finite local counterterms that eliminate the explicit symmetry breaking, thus restoring superconformal invariance up to anomalies. However, this necessarily renders both Q- and S-supersymmetries anomalous, as is manifest starting at 4-point functions of conformal multiplet currents. The paper contains a detailed discussion of a number of issues and subtleties related to Ward identities that may be useful in a wider context.
Gravitons in a Casimir box
Authors: Alessio Francesco , Barnich Glenn , Bronte Martin 
Published: February 2021

Abstract
The partition function of gravitons with Casimir-type boundary conditions is worked out. The simplest box that allows one to achieve full analytical control consists of a slab geometry with two infinite parallel planes separated by a distance d. In this setting, linearized gravity, like electromagnetism, is equivalent to two free massless scalar fields, one with Dirichlet and one with Neumann boundary conditions, which in turn may be combined into a single massless scalar with periodic boundary conditions on an interval of length 2d. When turning on a chemical potential for suitably adapted spin angular momentum, the partition function is modular covariant and expressed in terms of an Eisenstein series. It coincides with that for photons. At high temperature, the result provides in closed form all sub-leading finite-size corrections to the standard (gravitational) black body result. More interesting is the low-temperature/small distance expansion where the leading contribution to the partition function is linear in inverse temperature and given in terms of the Casimir energy of the system, whereas the leading contribution to the entropy is proportional to the area and originates from gravitons propagating parallel to the plates.
Continuous flattening of the 2-dimensional skeleton of a regular 24-cell
Authors: Itoh Jin-ichi , Nara Chie 
Published: February 2021

AbstractBellow theorem says that any polyhedron with rigid faces cannot change its volume even if it is flexible. The problem on continuous flattenig of polyhedra with non-rigid faces proposed by Demaine et al. was solved for all convex polyhedra by using the notion of moving creases to change some of the faces. This problem was extended to a problem on continuous flattening of the 2-dimensional skeleton of higher dimensional polytopes. This problem was solved for all regular polytopes except three types, the 24-cell, the 120-cell, and the 600-cell. This article addresses the 24-cell and gives a continuous flattening motion for its 2-skeleton, which is related to the Jitterbug by Buckminster Fuller.
Early prediction of biomass in hybrid rye based on hyperspectral data surpasses genomic predictability in less-related breeding material
Authors: Galán Rodrigo José , Bernal-Vasquez Angela-Maria , Jebsen Christian , Piepho Hans-Peter , Thorwarth Patrick , Steffan Philipp , Gordillo Andres , Miedaner Thomas 
Published: February 2021

AbstractKey messageHyperspectral data is a promising complement to genomic data to predict biomass under scenarios of low genetic relatedness. Sufficient environmental connectivity between data used for model training and validation is required.AbstractThe demand for sustainable sources of biomass is increasing worldwide. The early prediction of biomass via indirect selection of dry matter yield (DMY) based on hyperspectral and/or genomic prediction is crucial to affordably untap the potential of winter rye (Secale cerealeL.) as a dual-purpose crop. However, this estimation involves multiple genetic backgrounds and genetic relatedness is a crucial factor in genomic selection (GS). To assess the prospect of prediction using reflectance data as a suitable complement to GS for biomass breeding, the influence of trait heritability ($$H^{2}$$H2) and genetic relatedness were compared. Models were based on genomic (GBLUP) and hyperspectral reflectance-derived (HBLUP) relationship matrices to predict DMY and other biomass-related traits such as dry matter content (DMC) and fresh matter yield (FMY). For this, 270 elite rye lines from nine interconnected bi-parental families were genotyped using a 10 k-SNP array and phenotyped as testcrosses at four locations in two years (eight environments). From 400 discrete narrow bands (410 nm–993 nm) collected by an uncrewed aerial vehicle (UAV) on two dates in each environment, 32 hyperspectral bands previously selected by Lasso were incorporated into a prediction model. HBLUP showed higher prediction abilities (0.41 – 0.61) than GBLUP (0.14 – 0.28) under a decreased genetic relationship, especially for mid-heritable traits (FMY and DMY), suggesting that HBLUP is much less affected by relatedness and$$H^{2}$$H2. However, the predictive power of both models was largely affected by environmental variances. Prediction abilities for DMY were further enhanced (up to 20%) by integrating both matrices and plant height into a bivariate model. Thus, data derived from high-throughput phenotyping emerges as a suitable strategy to efficiently leverage selection gains in biomass rye breeding; however, sufficient environmental connectivity is needed.
Mid-infrared photodetector based on 2D material metamaterial with negative index properties for a wide range of angles near vertical illumination
Authors: Ponizovskaya Devine E. 
Published: February 2021

AbstractWe present the vertically illuminated Si compatible mid-infrared photodetectors based on graphene that forms negative-index metamaterial. The coupling into a 2D layer at the angles near normal to the surface is negligible without the help of a metamaterial. We propose a low loss metamaterial, the dielectric structure with the nano/microholes through 2D materials that supports a resonance and enhances quantum efficiency in a wide range of incident angles.
The linked legal data landscape: linking legal data across different countries
Authors: Filtz Erwin , Kirrane Sabrina , Polleres Axel 
Published: February 2021

AbstractThe European Union is working towards harmonizing legislation across Europe, in order to improve cross-border interchange of legal information. This goal is supported for instance via standards such as the European Law Identifier (ELI) and the European Case Law Identifier (ECLI), which provide technical specifications for Web identifiers and suggestions for vocabularies to be used to describe metadata pertaining to legal documents in a machine readable format. Notably, these ECLI and ELI metadata standards adhere to the RDF data format which forms the basis of Linked Data, and therefore have the potential to form a basis for a pan-European legal Knowledge Graph. Unfortunately, to date said specifications have only been partially adopted by EU member states. In this paper we describe a methodology to transform the existing legal information system used in Austria to such a legal knowledge graph covering different steps from modeling national specific aspects, to population, and finally the integration of legal data from other countries through linked data. We demonstrate the usefulness of this approach by exemplifying practical use cases from legal information search, which are not possible in an automated fashion so far.
Molecular evidence of species- and subspecies-level distinctions in the rare Orchis patens s.l. and implications for conservation
Authors: Calevo Jacopo , Gargiulo Roberta , Bersweden Leif , Viruel Juan , González-Montelongo Cristina , Rebbas Khellaf , Boutabia Lamia , Fay Michael F. 
Published: February 2021

AbstractCharacterizing genetic diversity and structure of populations is essential for the effective conservation of threatened species.Orchis patenssensu lato is a narrowly distributed tetraploid species with a disjunct distribution (i.e., Northern Italy, North Africa and the Canary Islands), which is facing a severe decline. In this study, we evaluated levels of genetic diversity and population structuring using 12 new nuclear microsatellite markers. Our analyses of genetic differentiation based on multiple approaches (Structure analysis, PCA analysis, andF-statistics using the ploidy-independentRho-index) showed that gene flow is low across the range ofO. patens s.l., particularly in the Canary Islands. Clear differences in allele frequencies between Italy, Algeria and the Canary Islands underlie the genetic differentiation retrieved. Our study provides support for the recognition ofO. canariensisas a sister species toO. patensand the separation of the Italian populations as a new subspecies ofO. patens. Despite the high heterozygosity values found in all populations (ranging from 0.4 to 0.7), compatible with the tetraploid status of the species, small population sizes and reduced gene flow will be likely detrimental for the different populations in the long term, and we recommend immediate conservation actions to counteract further fragmentation and population decline.
“We’re Just Geeks”: Disciplinary Identifications Among Business Students and Their Implications for Personal Responsibility
Authors: Blasco Maribel 
Published: February 2021

AbstractThis research shows how business students’ disciplinary specializations can affect their sense of personal responsibility by providing rationalizations for moral disengagement. It thereby conceptualizes business students’ disciplinary specializations as a key dimension of the business school responsibility learning environment. Students use four main rationalizations to displace responsibility variously away from their own disciplinary specializations, to claim responsibility as the prerogative of their specialization, and to shiftirresponsibility onto disciplinary out-groups. Yet despite their disciplinary identifications, students largely rationalized that their sense of responsibility was an individual matter that was unlikely to be affected by contextual influences, and they attributedirresponsible behavior to incorrigible ‘bad apples.’ A theoretical model is offered which illustrates these dynamics by combining Bandura’s social cognitive theory with social identity theory. The research is based on secondary data, specifically focus-group interviews conducted with undergraduate students at a major Scandinavian business school in connection with the implementation of the UN Principles for Responsible Management Education (PRME) initiative. The implications for management education include the need to strengthen students’ ‘disciplinary reflexivity,’ and to explicitly address the tension between students’ disciplinary solidarities and their faith in their own individual moral infallibility.
Change in mean and extreme temperature at Yingkou station in Northeast China from 1904 to 2017
Authors: Xue Xiaoying , Ren Guoyu , Sun Xiubao , Zhang Panfeng , Ren Yuyu , Zhang Siqi , Zhao Chunyu , Yu Xiujing 
Published: February 2021

AbstractThe understanding of centennial trends of extreme temperature has been impeded due to the lack of early-year observations. In this paper, we collect and digitize the daily temperature data set of Northeast China Yingkou meteorological station since 1904. After quality control and homogenization, we analyze the changes of mean and extreme temperature in the past 114 years. The results show that mean temperature (Tmean), maximum temperature (Tmax), and minimum temperature (Tmin) all have increasing trends during 1904–2017. The increase of Tmin is the most obvious with the rate of 0.34 °C/decade. The most significant warming occurs in spring and winter with the rate of Tmean reaching 0.32 °C/decade and 0.31 °C/decade, respectively. Most of the extreme temperature indices as defined using absolute and relative thresholds of Tmax and Tmin also show significant changes, with cold events witnessing a more significant downward trend. The change is similar to that reported for global land and China for the past six decades. It is also found that the extreme highest temperature (1958) and lowest temperature (1920) records all occurred in the first half of the whole period, and the change of extreme temperature indices before 1950 is different from that of the recent decades, in particular for diurnal temperature range (DTR), which shows an opposite trend in the two time periods.
Gait Patterns and Mood in Everyday Life: A Comparison Between Depressed Patients and Non-depressed Controls
Authors: Adolph Dirk , Tschacher Wolfgang , Niemeyer Helen , Michalak Johannes 
Published: February 2021

Abstract
Background
Previous laboratory findings suggest deviant gait characteristics in depressed individuals (i.e., reduced walking speed and vertical up-and-down movements, larger lateral swaying movements, slumped posture). However, since most studies to date assessed gait in the laboratory, it is largely an open question whether this association also holds in more naturalistic, everyday life settings. Thus, within the current study we (1) aimed at replicating these results in an everyday life and (2) investigated whether gait characteristics could predict change in current mood.

Methods
We recruited a sample of patients (n = 35) suffering from major depressive disorder and a sample of age and gender matched non-depressed controls (n = 36). During a 2-day assessment we continuously recorded gait patterns, general movement intensity and repetitively assessed the participant’s current mood.

Results
We replicated previous laboratory results and found that patients as compared to non-depressed controls showed reduced walking speed and reduced vertical up-and-down movements, as well as a slumped posture during everyday life episodes of walking. Moreover, independent of clinical diagnoses, higher walking speed, and more vertical up-and-down movements significantly predicted more subsequent positive mood, while changes in mood did not predict subsequent changes in gait patterns.

Conclusion
In sum, our results support expectations that embodiment (i.e., the relationship between bodily expression of emotion and emotion processing itself) in depression is also observable in naturalistic settings, and that depression is bodily manifested in the way people walk. The data further suggest that motor displays affect mood in everyday life.