bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relativistic coupled‐cluster and equation‐of‐motion coupled‐cluster methods
Authors: Liu Junzi , Cheng Lan 
Published: May 2021

AbstractThe development of relativistic coupled‐cluster (CC) and equation‐of‐motion coupled‐cluster (EOM‐CC) methods is reviewed. An emphasis is placed on recent efforts to improve the computational efficiency of CC and EOM‐CC calculations with non‐perturbative treatments of spin‐orbit coupling (SO‐CC and EOM‐CC) by partially recovering spin symmetry in the formulations. Example calculations of electronic ground state as well as valence‐excited and core‐excited states for molecules containing heavy elements are presented to demonstrate the applicability and usefulness of the SO‐CC and EOM‐CC methods. Future directions for the development of the SO‐CC and EOM‐CC methods are also discussed.This article is categorized under:
Electronic Structure Theory > Ab Initio Electronic Structure Methods
Emotional contagion in nonhuman animals: A review
Authors: Pérez‐Manrique Ana , Gomila Antoni 
Published: May 2021

AbstractEmotional contagion, the emotional state‐matching of an individual with another, seems to be crucial for many social species. In recent years evidence on emotional contagion in different animal species has accumulated. However, despite its adaptative advantages and its presumed simplicity, the study and direct demonstration of this phenomenon present more complexities than previously thought. For these reasons, a review of the literature on emotional contagion in nonhuman species is timely to integrate current findings. In this paper thus, we carry out a comprehensive review of the most relevant studies on emotional contagion in animals and discuss the main problems and challenges of the field. We conclude that more research is needed to broaden our understanding of the mechanisms and functions of emotional contagion and the extent to which this process is present in a wide variety of species. Furthermore, the comparative study of emotional contagion would benefit from the use of systematized paradigms including both behavioral and physiological measures and the simultaneous recording of the responses of the interacting individuals to reliably assess an emotional state‐matching between them and reliable controls.This article is categorized under:
Cognitive Biology > Evolutionary Roots of Cognition
Psychology > Comparative Psychology
Psychology > Emotion and Motivation
Multi‐fidelity digital twin structural model for a sub‐scale downwind wind turbine rotor blade
Authors: Chetan Mayank , Yao Shulong , Griffith D. Todd 
Published: May 2021

AbstractThis paper presents the development of a multi‐fidelity digital twin structural model (virtual model) of an as‐built wind turbine blade. The goal is to develop and demonstrate an approach to produce an accurate and detailed model of the as‐built blade for use in verifying the performance of the operating two‐bladed, downwind rotor. The digital twin model development methodology, presented herein, involves a novel calibration process to integrate a wide range of information including design specifications, manufacturing information, and structural testing data (modal and static) to produce a multi‐fidelity digital twin structural model: a detailed high‐fidelity model (i.e., 3D finite element analysis [FEA]) and consistent beam‐type models for aeroelastic simulation. A key element is that the multi‐fidelity structural digital twin method follows the rotor from the stages of design, to manufacturing, then to the ground testing and field operation. The result of this comprehensive approach is an accurate multi‐fidelity digital twin structural model for the geometric, structural, and structural dynamic properties of the as‐built blade within a 1% match in mass properties, 3.2% in blade frequencies, and 6% in deflection. The different stages of processing this information within the methodology are discussed. The rotor examined is the SUMR‐Demonstrator (SUMR‐D), which was installed on the Controls Advanced Research Testbed (CART‐2) wind turbine at the National Wind Technology Center. The digital twin model developed here was utilized to design controllers to safely operate SUMR‐D in field tests, which are providing additional data for further evaluation and development of the multi‐fidelity digital twin structural model.
Applications of optimization models for electricity distribution networks
Authors: Claeys Sander , Vanin Marta , Geth Frederik , Deconinck Geert 
Published: May 2021

AbstractIncreased penetration of low‐carbon technologies, such as residential photovoltaic systems, electric vehicles, and batteries, can potentially cause voltage quality issues in distribution networks. Active distribution networks adopt control schemes where these assets are actively managed to prevent potential issues, increasing the network utilization. Mathematical optimization is a key technology in enabling such applications, either directly as the underlying solution, or for benchmarking effectiveness. As networks are operated closer to their engineering limits, models representing distribution network physics become increasingly important. This article reviews how distribution networks are modeled with varying degrees of detail in the context of optimization problems. It goes on to catalog the applications that use such models, and ends with an overview of toolchains to implement them, to enable the transition from the passive to active management of the distribution system.This article is categorized under:Energy Systems Analysis > Systems and Infrastructure
Inclusion and Resilience in the Bioeconomy
Authors: Asveld Lotte 
Published: May 2021

AbstractNew technological developments such as CRISPR-Cas, advanced genetic sequencing and the digitalization of agriculture offer promising prospects to realize the potential of a sustainable bioeconomy. At the same time, enormous challenges abound such as the pressure on biodiversity and the associated risk of pandemics, climate change and the ever-increasing global economic inequality. The bioeconomy can play a beneficial role in this; however, this will only be possible if the bioeconomy is developed on the basis of inclusion. In this chapter I will explain the relevance of inclusion for the bioeconomy and describe some of the sociotechnical developments where inclusion should be realized in order to build a resilient and sustainable bioeconomy. These developments include biosphere capacity, global biobased value chains, digital genetic resources and the digitalization of agriculture. I will conclude with the question of who bears responsibility for an inclusive bioeconomy.
Gauge-invariant TMD factorization for Drell-Yan hadronic tensor at small x
Authors: Balitsky I. 
Published: May 2021

Abstract
The Drell-Yan hadronic tensor for electromagnetic (EM) current is calculated in the Sudakov region $$ s\gg {Q}^2\gg {q}_{\perp}^2 $$
s
≫

Q
2

≫

q
⊥
2

with $$ \frac{1}{Q^2} $$

1

Q
2

accuracy, first at the tree level and then with the double-log accuracy. It is demonstrated that in the leading order in Nc the higher-twist quark-quark-gluon TMDs reduce to leading-twist TMDs due to QCD equation of motion. The resulting tensor for unpolarized hadrons is EM gauge-invariant and depends on two leading-twist TMDs: f1 responsible for total DY cross section, and Boer-Mulders function $$ {h}_1^{\perp } $$

h
1
⊥

. The order-of-magnitude estimates of angular distributions for DY process seem to agree with LHC results at corresponding kinematics.
Inozemtsev system as Seiberg-Witten integrable system
Authors: Argyres Philip C. , Chalykh Oleg , Lü Yongchao 
Published: May 2021

Abstract
In this work we establish that the Inozemtsev system is the Seiberg-Witten integrable system encoding the Coulomb branch physics of 4d $$ \mathcal{N} $$
N
= 2 USp(2N) gauge theory with four fundamental and (for N ≥ 2) one antisymmetric tensor hypermultiplets. We describe the transformation from the spectral curves and canonical one-forms of the Inozemtsev system in the N = 1 and N = 2 cases to the Seiberg-Witten curves and differentials explicitly, along with the explicit matching of the modulus of the elliptic curve of spectral parameters to the gauge coupling of the field theory, and of the couplings of the Inozemtsev system to the field theory mass parameters. This result is a particular instance of a more general correspondence between crystallographic elliptic Calogero-Moser systems with Seiberg-Witten integrable systems, which will be explored in future work.
Co-occurrence and potential resource partitioning between oligochaetes and chironomid larvae in a sediment depth gradient
Authors: Kornijów Ryszard , Pawlikowski Krzysztof , Błędzki Leszek A. , Drgas Aleksander , Piwosz Kasia , Ameryk Anetta , Całkiewicz Joanna 
Published: May 2021

AbstractAlthough detritivorous Tubificinae and chironomid larvae are important groups in functioning of both, fresh and brackish water ecosystem, their co-occurrence patterns in sediment is weakly known. We carried out two-year-long research in the brackish Vistula Lagoon (southern Baltic Sea), where both Tubificinae (Limnodrilus hoffmeisteriandPotamothrix hammoniensis) and larvae ofChironomus balatonicusoccur in high densities. Because of different source of their food, we hypothesized that the ecological interactions between those two groups of detritivores are not antagonistic, thus allowing for their co-occurrence along the depth of sediment profile with lack of competition for space. Here we show that maximum burrowing depth, occasionally reaching 25 cm was significantly affected by the total density of the each group in the entire core. Tubificinae andC. balatonicusshowed the highest density at 0–10 cm depth, where they co-occurred most frequently, with significant co-occurrence in the layers of 0–2 cm and 2–5 cm. We propose a hypothetical model of interactions between apparently the same functional groups and the complementary role they play in sediment reworking. It points to their coexistence in the shared microhabitat, but using space and food resources differently. Also, the consequences of their activity and habitat structuring are opposite—Chironomuslarvae mostly affect the deeper layers of the sediments, while Oligochaeta both the deeper and surface layers. Thus, their requirements and ecological roles seem not to overlap, preventing competitive exclusion and allowing for co-occurrence.
Polyanalytic Toeplitz Operators: Isomorphisms, Symbolic Calculus and Approximation of Weyl Operators
Authors: Keller Johannes , Luef Franz 
Published: May 2021

AbstractWe discuss an extension of Toeplitz quantization based on polyanalytic functions. We derive isomorphism theorem for polyanalytic Toeplitz operators between weighted Sobolev-Fock spaces of polyanalytic functions, which are images of modulation spaces under polyanalytic Bargmann transforms. This generalizes well-known results from the analytic setting. Finally, we derive an asymptotic symbol calculus and present an asymptotic expansion of complex Weyl operators in terms of polyanalytic Toeplitz operators.
Experimental investigation of the effects of cryogenic cooling on tool life in Ti6Al4V milling
Authors: Albertelli Paolo , Mussi Valerio , Strano Matteo , Monno Michele 
Published: May 2021

AbstractIn this paper, the results of an experimental campaign of cryogenic milling are presented and discussed. For this purpose, a specific experimental setup that allowed to feed the liquid nitrogen LN through the tool nozzles was used. Tool life tests were carried out at different cutting speeds. The tool duration data were collected and used to identify the parameters of the Taylor’s model. Different end-of-life criteria for the tool inserts were even investigated. The achieved results are compared to those obtained using conventional cooling. It was observed that at low cutting velocity, conventional cooling still assures longer tool lives than in cryogenic condition. Since in cryogenic milling the increasing of the cutting velocity is not so detrimental as in conventional cutting, at high cutting speed (from 125 m/min) longer tool durations can be achieved. Statistical analyses on the model parameters were carried out to confirm the presented findings. The analysis of the effect of the cooling approach on the main wear mechanisms was also reported. At low cutting speed, adhesion and chipping phenomena affected the tool duration mainly in cryogenic milling.
Non-covalent double bond sensors for gas-phase infrared spectroscopy of unsaturated fatty acids
Authors: Kirschbaum Carla , Greis Kim , Lettow Maike , Gewinner Sandy , Schöllkopf Wieland , Meijer Gerard , von Helden Gert , Pagel Kevin 
Published: May 2021

AbstractThe position and configuration of carbon-carbon double bonds in unsaturated fatty acids is crucial for their biological functions and influences health and disease. However, double bond isomers are not routinely distinguished by classical mass spectrometry workflows. Instead, they require sophisticated analytical approaches usually based on chemical derivatization and/or instrument modification. In this work, a novel strategy to investigate fatty acid double bond isomers (18:1) without prior chemical treatment or modification of the ion source was implemented by non-covalent adduct formation in the gas phase. Fatty acid adducts with sodium, pyridinium, trimethylammonium, dimethylammonium, and ammonium cations were characterized by a combination of cryogenic gas-phase infrared spectroscopy, ion mobility-mass spectrometry, and computational modeling. The results reveal subtle differences between double bond isomers and confirm three-dimensional geometries constrained by non-covalent ion-molecule interactions. Overall, this study on fatty acid adducts in the gas phase explores new avenues for the distinction of lipid double bond isomers and paves the way for further investigations of coordinating cations to increase resolution.
Graphical abstract
Voting power on a graph connected political space with an application to decision-making in the Council of the European Union
Authors: Benati Stefano , Vittucci Marzetti Giuseppe 
Published: May 2021

AbstractWe analyze the problem of computing the Banzhaf and Shapley power indices for graph restricted voting games, defined in a particular class of graphs, that we called line-clique. A line-clique graph is a model of a uni-dimensional political space in which voters with the same bliss point are the connected vertices of a clique and then other arcs connect nodes of consecutive cliques. The interest to this model comes from its correspondence to the spatial voting game: a model that has been proposed and used by political analysts to understand nations’ behavior and the political outcome of the bargaining process within the EU Council. Broadly speaking, the computation of a power index of a graph restricted game is strongly #P-complete, as it includes the enumeration of all winning coalitions. Nevertheless, we show that in this special class of graph coalitions can be enumerated by dynamic programming, resulting in a pseudo-polynomial algorithm and proving that the problem only weakly #P-complete. After implementing our new algorithms and finding that they are very fast in practice, we analyze the voting behavior in the EU Council, as for this application previous research compiled a large data set concerning nations’ political positions and political outcomes. We will test whether voting power has an effect on the political outcome, more precisely, whether nations that are favored by their weight and position can influence the political outcome to their advantages. Using linear regressions, we will see that unrestricted power indices are not capable of any predictive property, but graph restricted indices are. The statistic evidence shows that the combination of voting weight and network position is a source of power that affects the political outcome to the advantage of a country.
Understanding nonsense correlation between (independent) random walks in finite samples
Authors: Hassler Uwe , Hosseinkouchack Mehdi 
Published: May 2021

AbstractConsider two independent random walks. By chance, there will be spells of association between them where the two processes move in the same direction, or in opposite direction. We compute the probabilities of the length of the longest spell of such random association for a given sample size, and discuss measures like mean and mode of the exact distributions. We observe that long spells (relative to small sample sizes) of random association occur frequently, which explains why nonsense correlation between short independent random walks is the rule rather than the exception. The exact figures are compared with approximations. Our finite sample analysis as well as the approximations rely on two older results popularized by Révész (Stat Pap 31:95–101, 1990, Statistical Papers). Moreover, we consider spells of association between correlated random walks. Approximate probabilities are compared with finite sample Monte Carlo results.
DNN Expression Rate Analysis of High-Dimensional PDEs: Application to Option Pricing
Authors: Elbrächter Dennis , Grohs Philipp , Jentzen Arnulf , Schwab Christoph 
Published: May 2021

AbstractWe analyze approximation rates by deep ReLU networks of a class of multivariate solutions of Kolmogorov equations which arise in option pricing. Key technical devices are deep ReLU architectures capable of efficiently approximating tensor products. Combining this with results concerning the approximation of well-behaved (i.e., fulfilling some smoothness properties) univariate functions, this provides insights into rates of deep ReLU approximation of multivariate functions with tensor structures. We apply this in particular to the model problem given by the price of a European maximum option on a basket of d assets within the Black–Scholes model for European maximum option pricing. We prove that the solution to the d-variate option pricing problem can be approximated up to an $$\varepsilon $$
ε
-error by a deep ReLU network with depth $${\mathcal {O}}\big (\ln (d)\ln (\varepsilon ^{-1})+\ln (d)^2\big )$$

O

(

ln

(
d
)

ln

(

ε

-
1

)

+
ln

(
d
)

2

)

and $${\mathcal {O}}\big (d^{2+\frac{1}{n}}\varepsilon ^{-\frac{1}{n}}\big )$$

O

(

d

2
+

1
n

ε

-

1
n

)

nonzero weights, where $$n\in {\mathbb {N}}$$

n
∈
N

is arbitrary (with the constant implied in $${\mathcal {O}}(\cdot )$$

O
(
·
)

depending on n). The techniques developed in the constructive proof are of independent interest in the analysis of the expressive power of deep neural networks for solution manifolds of PDEs in high dimension.
Patients’ perceived walking abilities, daily-life gait behavior and gait quality before and 3 months after total knee arthroplasty
Authors: Fransen Bas L. , Pijnappels Mirjam , Butter Ise K. , Burger B. J. , van Dieën J. H. , Hoozemans M. J. M. 
Published: May 2021

Abstract
Introduction
Functional outcome and patients’ daily-life activities after total knee arthroplasty are becoming more important with a younger and more active patient population. In addition to patient-reported outcome measures (PROMs), trunk-based accelerometry has shown to be a promising method for evaluating gait function after total knee arthroplasty. The aim of this study was to evaluate daily-life perceived walking abilities, gait behavior and gait quality before and 3 months after total knee arthroplasty, using PROMs and trunk-based accelerometry.

Materials and methods
A cohort of 38 patients completed questionnaires including the Oxford Knee Score and modified Gait Efficacy Scale before and 3 months after primary unilateral total knee arthroplasty. At both time points, they wore a tri-axial accelerometer at the lower back for seven consecutive days and nights. Gait behavior was calculated using gait quantity and walking speed, and multiple gait quality parameters were calculated.

Results
Significant improvements were seen after 3 months in the Oxford Knee Score [median (interquartile range) 29 (10) vs 39 (8), p < 0.001] and modified Gait Efficacy Scale [median (interquartile range) 67 (24) vs 79 (25), p = 0.001]. No significant changes were observed in gait behavior (quantity and speed) or gait quality variables.

Conclusions
In contrast to the significant improvements in patients’ perception of their walking abilities and PROMs, patients did not show improvements in gait behavior and gait quality. This implies that after 3 months patients’ perceived functional abilities after total knee arthroplasty do not necessarily represent their actual daily-life quantity and quality of gait, and that more focus is needed on postoperative rehabilitation to improve gait and functional behavior.
In vivo measurements of spinal stiffness according to a stepwise increase of axial load
Authors: Glaus Lea Suzanne , Hofstetter Léonie , Guekos Alexandros , Schweinhardt Petra , Swanenburg Jaap 
Published: May 2021

Abstract
Background
The spine has a complex motor control. Its different stabilization mechanisms through passive, active, and neurological subsystems may result in spinal stiffness. To better understand lumbar spinal motor control, this study aimed to measure the effects of increasing the axial load on spinal stiffness.

Methods
A total of 19 healthy young participants (mean age, 24 ± 2.1 years; 8 males and 11 females) were assessed in an upright standing position. Under different axial loads, the posterior-to-anterior spinal stiffness of the thoracic and lumbar spine was measured. Loads were 0%, 10%, 45%, and 80% of the participant’s body weight.

Results
Data were normally distributed and showed excellent reliability. A repeated-measures analysis of variance with a Greenhouse–Geisser correction showed an effect of the loading condition on the mean spinal stiffness [F (2.6, 744) = 3.456, p < 0.001]. Vertebrae and loading had no interaction [F (2.6, 741) = 0.656, p = 0.559]. Post hoc tests using Bonferroni correction revealed no changes with 10% loading (p = 1.000), and with every additional step of loading, spinal stiffness decreased: 0% or 10–45% loading (p < 0.001), 0% or 10–80% loading (p < 0.001), and 45–80% (p < 0.001).

Conclusion
We conclude that a load of ≥ 45% of the participant’s body weight can lead to changes in the spinal motor control. An axial load of 10% showed no significant changes. Rehabilitation should include high-axial-load exercise if needed in everyday living.
A free boundary characterisation of the Root barrier for Markov processes
Authors: Gassiat Paul , Oberhauser Harald , Zou Christina Z. 
Published: May 2021

AbstractWe study the existence, optimality, and construction of non-randomised stopping times that solve the Skorokhod embedding problem (SEP) for Markov processes which satisfy a duality assumption. These stopping times are hitting times of space-time subsets, so-called Root barriers. Our main result is, besides the existence and optimality, a potential-theoretic characterisation of this Root barrier as a free boundary. If the generator of the Markov process is sufficiently regular, this reduces to an obstacle PDE that has the Root barrier as free boundary and thereby generalises previous results from one-dimensional diffusions to Markov processes. However, our characterisation always applies and allows, at least in principle, to compute the Root barrier by dynamic programming, even when the well-posedness of the informally associated obstacle PDE is not clear. Finally, we demonstrate the flexibility of our method by replacing time by an additive functional in Root’s construction. Already for multi-dimensional Brownian motion this leads to new class of constructive solutions of (SEP).