bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the closure of the Hodge locus of positive period dimension
Authors: Klingler B. , Otwinowska A. 
Published: March 2021

AbstractGiven $${{\mathbb {V}}}$$
V
a polarizable variation of $${{\mathbb {Z}}}$$
Z
-Hodge structures on a smooth connected complex quasi-projective variety S, the Hodge locus for $${{\mathbb {V}}}^\otimes $$

V

⊗

is the set of closed points s of S where the fiber $${{\mathbb {V}}}_s$$

V
s

has more Hodge tensors than the very general one. A classical result of Cattani, Deligne and Kaplan states that the Hodge locus for $${{\mathbb {V}}}^\otimes $$

V

⊗

is a countable union of closed irreducible algebraic subvarieties of S, called the special subvarieties of S for $${{\mathbb {V}}}$$
V
. Under the assumption that the adjoint group of the generic Mumford–Tate group of $${{\mathbb {V}}}$$
V
is simple we prove that the union of the special subvarieties for $${{\mathbb {V}}}$$
V
whose image under the period map is not a point is either a closed algebraic subvariety of S or is Zariski-dense in S. This implies for instance the following typical intersection statement: given a Hodge-generic closed irreducible algebraic subvariety S of the moduli space $${{\mathcal {A}}}_g$$

A
g

of principally polarized Abelian varieties of dimension g, the union of the positive dimensional irreducible components of the intersection of S with the strict special subvarieties of $${{\mathcal {A}}}_g$$

A
g

is either a closed algebraic subvariety of S or is Zariski-dense in S.
CMR feature tracking strain patterns and their association with circulating cardiac biomarkers in patients with hypertrophic cardiomyopathy
Authors: Cavus Ersin , Muellerleile Kai , Schellert Samuel , Schneider Jan , Tahir Enver , Chevalier Celeste , Jahnke Charlotte , Radunski Ulf K. , Adam Gerhard , Kirchhof Paulus , Blankenberg Stefan , Lund Gunnar K. , Avanesov Maxim , Patten Monica 
Published: March 2021

Abstract
Aims
CMR feature tracking strain (CMR-FT) provides prognostic information. However, there is a paucity of data in hypertrophic cardiomyopathy (HCM). We sought to analyze global CMR-FT parameters in all four cardiac chambers and to assess associations with NT-proBNP and cardiac troponin T (hsTnT) in patients with HCM.

Methods
This retrospective study included 144 HCM patients and 16 healthy controls with CMR at 1.5 T. Analyses were performed on standard steady-state free precession cine (SSFP) CMR data using a commercially available software. Global left ventricular (LV) strain was assessed as longitudinal (LVLAX-GLS), circumferential (LVLAX-GCS) and radial strain (LVLAX-GRS) on long -axis (LAX) and as LVSAX-GCS and LVSAX-GRS on short- axis (SAX). Right ventricular (RV-GLS), left atrial (LA-GLS) and right atrial (RA-GLS) strain were assessed on LAX.

Results
We found LVLAX-GLS [− 18.9 (− 22.0, − 16.0), − 23.5 (− 25.5, − 22.0) %, p = 0.0001), LVSAX-GRS [86.8 (65.9–115.5), 119.6 (91.3–143.7) %, p = 0.001] and LALAX-GLS [LA2CH-GLS 29.2 (19.1–37.7), LA2CH-GLS 38.2 (34.3–47.1) %, p = 0.0036; LA4CH-GLS 22.4 (14.6–30.7) vs. LA4CH-GLS 33.4 (28.4–37.3) %, p = 0.0033] to be impaired in HCM compared to healthy controls despite normal LVEF. Furthermore, LV and LA strain parameters were impaired in HCM with elevated NT-proBNP and/or hsTnT, despite preserved LVEF compared to HCM with normal biomarker levels. There was a moderate correlation of LV and LA CMR-FT with levels of NT-proBNP and hsTnT.

Conclusion
CMR-FT reveals LV and LA dysfunction in HCM despite normal LVEF. The association between impaired LV strain and elevated NT-proBNP and hsTnT indicates a link between unapparent functional abnormalities and disease severity in HCM.

Graphic abstract

Typical CMR-FT findings in patients with hypertrophic cardiomyopathy
Explaining psychosocial care among unaccompanied minor refugees: a realist review
Authors: Ulrich Hanna-Sophie , Kohler Emma , Spallek Jacob , Richter Matthias , Clauß Daniel , Mlinarić Martin 
Published: March 2021

AbstractResearch on the psychosocial care (PSC) of unaccompanied minor refugees (UMRs) has mainly taken a socioepidemiological approach and has focused on the perspectives of experts in the field. In contrast, the knowledge concerning the differing context factors and the underlying mechanisms of current PSC which could inform policy recommendations is scant. The study aims at unravelling the contexts, mechanisms and outcomes of PSC for UMRs. For a realist review (RR), scientific evidence and gray literature were synthesised consistent with the RAMESES publication standards for realist synthesis. Based on an iterative keyword search in electronic databases (e.g., PubMed) and screening, 34 works from 2005 to 2019 were included in a realist synthesis. Theory-informed context–mechanism–outcome configurations (CMOs) were extracted, to explain underlying processes and mechanisms. Characterised by their interrelatedness, the dominant CMOs included the UMRs’ intersections of transitions (e.g., adolescence and migration), their needs for culture-, and gender-sensitive PSC, and the undersupply of PSC. These contexts and outcomes are mediated by pre-, peri- and post-migratory stressors as well as care structures and are moreover influenced by overarching discourses and concepts. They comprise adverse and beneficial mechanisms in the PSC of UMRs. The existing literature grasps the PSC of UMRs by different disciplines and approaches but does not offer a comprehensive overview on micro–macro intersections and included discourses. The inclusion of lay perspectives and an intersectional approach could inform health service research. The reflection of UMR-related categorical constructs of resilience and vulnerability, discourses of othering, as well as restrictive health policies may guide policy recommendations.
Development of test methodologies for experimental lifetime investigations of tidal turbines
Authors: Rapp Tobias , Jacobs Georg , Bosse Dennis , Schröder Tim , Starzmann Ralf , Kaufmann Nicholas , Grassow Matthias , Scholl Stefan , Zweiffel Maximilian 
Published: March 2021

AbstractAs a regenerative energy source, tidal energy can significantly contribute to greenhouse gas reduction, even though the potentially achievable energy output is lower than that of wind or solar energy. The decisive advantage of tidal turbines lies in the simply and reliably predictable energy output. However, their commercial use has so far been impeded by the fact that on the one hand complex mechanical systems are required to convert energy of tidal currents and on the other hand multi-axial loading conditions caused by turbulent ocean currents act on the turbine. For this reason, field tests on prototypes are an essential part of the development strategy to ensure operational reliability. However, in-field tests do not allow for accelerated lifetime testing, so that test bench experiments are becoming an increasingly important alternative. Today, established procedures for testing the turbines main bearings and gearing system are already available, both for setting up the required test configuration and for determining the corresponding test loads. However, the use of advanced calculation methods, such as the finite element method for stress calculation, requires a deep understanding of the examined components and hinders the transfer of the approaches to other components.To simplify the process of test loads determination, a general methodology is presented, which relies exclusively on standardized empirical calculation rules. Doing this, fatigue equivalent loads can be determined for any component in a simple process. It was shown that the achieved reduction in complexity opens further potential for test acceleration, since several components can be tested simultaneously.
Drivetrains on floating offshore wind turbines: lessons learned over the last 10 years
Authors: Nejad Amir R. , Torsvik Jone 
Published: March 2021

AbstractThis paper presents lessons learned from own research studies and field experiments with drivetrains on floating wind turbines over the last ten years. Drivetrains on floating support structures are exposed to wave-induced motions in addition to wind loading and motions. This study investigates the drivetrain-floater interactions from two different viewpoints: how drivetrain impacts the sub-structure design; and how drivetrain responses and life are affected by the floater and support structure motion. The first one is linked to the drivetrain technology and layout, while the second question addresses the influence of the wave-induced motion. The results for both perspectives are presented and discussed. Notably, it is highlighted that the effect of wave induced motions may not be as significant as the wind loading on the drivetrain responses particularly in larger turbines. Given the limited experience with floating wind turbines, however, more research is needed. The main aim with this article is to synthesize and share own research findings on the subject in the period since 2009, the year that the first full-scale floating wind turbine, Hywind Demo, entered operation in Norway.
CertBench: conclusions from the comparison of certification results derived on system test benches and in the field
Authors: Jassmann Uwe , Frehn Anica , Röttgers Heiko , Santjer Fritz , Mehler Christian , Beißel Thomas , Kaven Lennard , von den Hoff Daniel , Frühmann Richard , Azarian Soroush , Neshati Mohsen , Quistorf Gesa , Zuga Adam , Brennecke Martin , Jersch Torben , Schelenz Ralf 
Published: March 2021

AbstractThis paper presents measurement results of the world wide first successful certification the electrical properties of a wind turbine, solely based upon measurements obtained at a system test bench with HiL-System and grid emulator. For all certification relevant tests the results are compared to field measurements. The impact of the real-time models in the HiL-System as well as the converter-based grid emulator are discussed in this paper. For full converter wind turbine, different requirements for the model depth could be determined depending on the tests. Nevertheless, higher-quality models that reflect the plant behaviour better are recommended to reduce uncertainties within the certification process. This paper also shows that especially for grid failure events grid emulators require real-time impedance control, in order to emulate grid failures properly. Based on these findings, recommendations for the requirements on test bench components are formulated in this paper, in order to contribute to new certification guidelines. Overall, we conclude that based on the experiences made at two different system test benches, the vast majority of certification measurements can be carried out without limitation at such system test benches.
Optimization of spectral-domain optical coherence tomography with a supercontinuum source for in vivo motion detection of low reflective outer hair cells in guinea pig cochleae
Authors: Nin Fumiaki , Choi Samuel , Ota Takeru , Qi Zhang , Hibino Hiroshi 
Published: March 2021

AbstractSound evokes sub-nanoscale vibration within the sensory epithelium. The epithelium contains not only immotile cells but also contractile outer hair cells (OHCs) that actively shrink and elongate synchronously with the sound. However, the in vivo motion of OHCs has remained undetermined. The aim of this work is to perform high-resolution and -accuracy vibrometry in live guinea pigs with an SC-introduced spectral-domain optical coherence tomography system (SD-OCT). In this study, to reveal the effective contribution of SC source in the recording of the low reflective materials with the short total acquisition time, we compare the performances of the SC-introduced SD-OCT (SCSD-OCT) to that of the conventional SD-OCT. As inanimate comparison objects, we record a mirror, a piezo actuator, and glass windows. For the measurements in biological materials, we use in/ex vivo guinea pig cochleae. Our study achieved the optimization of a SD-OCT system for high-resolution in vivo vibrometry in the cochlear sensory epithelium, termed the organ of Corti, in mammalian cochlea. By introducing a supercontinuum (SC) light source and reducing the total acquisition time, we improve the axial resolution and overcome the difficulty in recording the low reflective material in the presence of biological noise. The high power of the SC source enables the system to achieve a spatial resolution of 1.72 ± 0.00 μm on a mirror and reducing the total acquisition time contributes to the high spatial accuracy of sub-nanoscale vibrometry. Our findings reveal the vibrations at the apical/basal region of OHCs and the extracellular matrix, basilar membrane.
Matroid bases with cardinality constraints on the intersection
Authors: Lendl Stefan , Peis Britta , Timmermans Veerle 
Published: March 2021

AbstractGiven two matroids $$\mathcal {M}_{1} = (E, \mathcal {B}_{1})$$

M
1

=

(
E
,

B
1

)

and $$\mathcal {M}_{2} = (E, \mathcal {B}_{2})$$

M
2

=

(
E
,

B
2

)

on a common ground set E with base sets $$\mathcal {B}_1$$

B
1

and $$\mathcal {B}_2$$

B
2

, some integer $$k \in \mathbb {N}$$

k
∈
N

, and two cost functions $$c_{1}, c_{2} :E \rightarrow \mathbb {R}$$

c
1

,

c
2

:
E
→
R

, we consider the optimization problem to find a basis $$X \in \mathcal {B}_{1}$$

X
∈

B
1

and a basis $$Y \in \mathcal {B}_{2}$$

Y
∈

B
2

minimizing the cost $$\sum _{e\in X} c_1(e)+\sum _{e\in Y} c_2(e)$$

∑

e
∈
X

c
1

(
e
)

+

∑

e
∈
Y

c
2

(
e
)

subject to either a lower bound constraint $$|X \cap Y| \le k$$

|
X
∩
Y
|
≤
k

, an upper bound constraint $$|X \cap Y| \ge k$$

|
X
∩
Y
|
≥
k

, or an equality constraint $$|X \cap Y| = k$$

|
X
∩
Y
|
=
k

on the size of the intersection of the two bases X and Y. The problem with lower bound constraint turns out to be a generalization of the Recoverable Robust Matroid problem under interval uncertainty representation for which the question for a strongly polynomial-time algorithm was left as an open question in Hradovich et al. (J Comb Optim 34(2):554–573, 2017). We show that the two problems with lower and upper bound constraints on the size of the intersection can be reduced to weighted matroid intersection, and thus be solved with a strongly polynomial-time primal-dual algorithm. We also present a strongly polynomial, primal-dual algorithm that computes a minimum cost solution for every feasible size of the intersection k in one run with asymptotic running time equal to one run of Frank’s matroid intersection algorithm. Additionally, we discuss generalizations of the problems from matroids to polymatroids, and from two to three or more matroids. We obtain a strongly polynomial time algorithm for the recoverable robust polymatroid base problem with interval uncertainties.
Quotient-space boundary element methods for scattering at complex screens
Authors: Claeys Xavier , Giacomel Lorenzo , Hiptmair Ralf , Urzúa-Torres Carolina 
Published: March 2021

AbstractA complex screen is an arrangement of panels that may not be even locally orientable because of junction lines. A comprehensive trace space framework for first-kind variational boundary integral equations on complex screens has been established in Claeys and Hiptmair (Integr Equ Oper Theory 77:167–197, 2013. https://doi.org/10.1007/s00020-013-2085-x) for the Helmholtz equation, and in Claeys and Hiptmair (Integr Equ Oper Theory 84:33–68, 2016. https://doi.org/10.1007/s00020-015-2242-5) for Maxwell’s equations in frequency domain. The gist is a quotient space perspective that allows to make sense of jumps of traces as factor spaces of multi-trace spaces modulo single-trace spaces without relying on orientation. This paves the way for formulating first-kind boundary integral equations in weak form posed on energy trace spaces. In this article we extend that idea to the Galerkin boundary element (BE) discretization of first-kind boundary integral equations. Instead of trying to approximate jumps directly, the new quotient space boundary element method employs a Galerkin BE approach in multi-trace boundary element spaces. This spawns discrete boundary integral equations with large null spaces comprised of single-trace functions. Yet, since the right-hand-sides of the linear systems of equations are consistent, Krylov subspace iterative solvers like GMRES are not affected by the presence of a kernel and still converge to a solution. This is strikingly confirmed by numerical tests.
The unknown agents of European cooperation, and their future
Authors: Brenninkmeijer Alex 
Published: March 2021

AbstractSince the Maastricht Treaty, the EU has created 37 agencies and bodies covering nearly every aspect of our daily lives. However, agencies have always played a supporting role, serving national interests as well as those of Brussels, and their pivotal role in bringing those interests together is often overlooked. As agencies have increasingly been used as a solution for addressing the challenges facing Europe, their relationship with the European Commission, the Member States and EU citizens also needs to evolve as a model for European cooperation. A few guiding principles are relevant for this purpose, and have already been set out in a performance audit entitled “Future of EU agencies – Potential for more flexibility and cooperation” for which I had the pleasure to serve as the reporting Member to the European Parliament.
“Listening to the Sounds of the Water”: Bringing Together Local Knowledge and Biophysical Data to Understand Climate-Related Hazard Dynamics
Authors: Pauli Natasha , Williams Mark , Henningsen Savuti , Davies Kevin , Chhom Chanchhaya , van Ogtrop Floris , Hak Sochanny , Boruff Bryan , Neef Andreas 
Published: March 2021

AbstractIntegrating local knowledge and scientific information can aid in co-developing locally relevant approaches for climate change adaptation and disaster risk reduction. Communities along the Mekong River have adapted to variability in temperature, rainfall, and flooding patterns over time. Rapid environmental change in the Mekong Basin presents a new set of challenges related to drought, altered seasonal rainfall, more frequent high-flow flood events, and water withdrawals for hydropower and irrigation. We present a multi-method approach to understand how local knowledge of the spatial and temporal patterns of floods, droughts, and rainfall can be integrated with scientific information along a flood-prone section of the lower Mekong River in Kratie Province, Cambodia. Participatory hazard mapping of community members’ knowledge of the movement of floodwaters through the landscape enabled interpretation of flood extent mapping using Synthetic Aperture Radar images from the Sentinel-1A satellite. Seasonal calendars of weather patterns and livelihood activities, together with local indicators of flooding, rainfall, and drought were compared with trends in 35 years of rainfall data, and highlighted “pressure points” at the beginning and end of the rainy season where agriculture may be particularly impacted by climate change. We discuss potential applications of our findings for adaptation and hazard planning.
End-to-end heart sound segmentation using deep convolutional recurrent network
Authors: Chen Yao , Sun Yanan , Lv Jiancheng , Jia Bijue , Huang Xiaoming 
Published: March 2021

AbstractHeart sound segmentation (HSS) aims to detect the four stages (first sound, systole, second heart sound and diastole) from a heart cycle in a phonocardiogram (PCG), which is an essential step in automatic auscultation analysis. Traditional HSS methods need to manually extract the features before dealing with HSS tasks. These artificial features highly rely on extraction algorithms, which often result in poor performance due to the different operating environments. In addition, the high-dimension and frequency characteristics of audio also challenge the traditional methods in effectively addressing HSS tasks. This paper presents a novel end-to-end method based on convolutional long short-term memory (CLSTM), which directly uses audio recording as input to address HSS tasks. Particularly, the convolutional layers are designed to extract the meaningful features and perform the downsampling, and the LSTM layers are developed to conduct the sequence recognition. Both components collectively improve the robustness and adaptability in processing the HSS tasks. Furthermore, the proposed CLSTM algorithm is easily extended to other complex heart sound annotation tasks, as it does not need to extract the characteristics of corresponding tasks in advance. In addition, the proposed algorithm can also be regarded as a powerful feature extraction tool, which can be integrated into the existing models for HSS. Experimental results on real-world PCG datasets, through comparisons to peer competitors, demonstrate the outstanding performance of the proposed algorithm.
Lockdown and Children’s Well-Being: Experiences of Children in Switzerland, Canada and Estonia
Authors: Stoecklin Daniel , Gervais Christine , Kutsar Dagmar , Heite Catrin 
Published: March 2021

AbstractThis paper addresses the well-being of children in Switzerland, Canada and Estonia, as they experienced the lockdown imposed by governments after the state of international public health emergency, declared by the World Health Organization on 30 January 2020. Suspension of school or starting with distance learning, cessation of extracurricular activities, closure of playgrounds, parks, shopping centres and loss of daily contacts with friends completely transformed children’s lives. The surveys conducted by the authors in individual ways, were all inspired by their membership to the Children’s Understandings of Well-Being network and involved the participation of 403 children aged 7–17 years old (229 girls and 174 boys). They present the emerging trends from the children’s narratives focusing on their experience of the lockdown in relation to family life, school life, contacts with friends, and in relation to space, time and self. During the lockdown leisure activities and hobbies, followed by life with friends and school life challenged relational well-being the most, while family life opened up new perspectives and generational solidarity. Staying at home and decreased physical activity impacted on the physical health of children, missing direct contacts with friends and teachers put social relations to test, fear of the virus decreased feeling safe and secure, and the lockdown restricted participation in society. The findings underline the relational nature of their well-being. More in-depth studies are needed to highlight the widening of inequalities and the balance between protection and participation of children.
Determinanten der kommunalen Steuerpolitik
Authors: Person Christian 
Published: March 2021

ZusammenfassungDie eigenverantwortliche Festsetzung der kommunalen Steuersätze stellt ein wichtiges Element der verfassungsrechtlich verbrieften Finanzautonomie kommunaler Gebietskörperschaften dar. Diese Handlungsspielräume werden von den Kommunen unterschiedlich wahrgenommen. Folglich bestehen zwischen den Kommunen erhebliche Divergenzen in der Ausgestaltung ihrer Steuerpolitik. Daher stellt sich die Frage, wie sich diese Diskrepanzen erklären lassen. Sind diese auf sozioökonomische, budgetäre oder parteipolitische Einflussfaktoren zurückzuführen? Zur Klärung dieser Frage wird im Rahmen des Beitrags die kommunale Realsteuerpolitik in sechs Bundesländern zwischen 2004 und 2013 analysiert. Dabei stellen sich vor allem sozioökonomische und budgetäre Einflussfaktoren als erklärungskräftig heraus, wohingegen Parteieneffekte nur vereinzelt festzustellen sind. Dies verdeutlicht, dass der Handlungsspielraum von Parteien auf lokaler Ebene durch den wachsenden fiskalischen Problemdruck zunehmend eingeengt wird. Lediglich bei den Grundsteuern scheinen begrenzte Gestaltungsspielräume zu bestehen, die sich teilweise in parteipolitisch bedingten Differenzen manifestieren. Durch die Identifikation relevanter Determinanten der kommunalen Steuerpolitik leistet der Aufsatz somit einen Beitrag zu einem besseren Verständnis lokaler Haushaltspolitik.