bluuebunny/crossref_metadata_2025 huggingface dataset:
Finding Provably Optimal Markov Chains
Authors: Spel Jip , Junges Sebastian , Katoen Joost-Pieter
Published: March 2021

Parametric Markov chains (pMCs) are Markov chains with symbolic (aka: parametric) transition probabilities. They are a convenient operational model to treat robustness against uncertainties. A typical objective is to find the parameter values that maximize the reachability of some target states. In this paper, we consider automatically proving robustness, that is, an$$\varepsilon $$ε-close upper bound on the maximal reachability probability. The result of our procedure actually provides an almost-optimal parameter valuation along with this upper bound.

We propose to tackle these ETR-hard problems by a tight combination of two significantly different techniques: monotonicity checking and parameter lifting. The former builds a partial order on states to check whether a pMC is (local or global) monotonic in a certain parameter, whereas parameter lifting is an abstraction technique based on the iterative evaluation of pMCs without parameter dependencies. We explain our novel algorithmic approach and experimentally show that we significantly improve the time to determine almost-optimal synthesis.
Multi-objective Optimization of Long-run Average and Total Rewards
Authors: Quatmann Tim , Katoen Joost-Pieter
Published: March 2021

This paper presents an efficient procedure for multi-objective model checking of long-run average reward (aka: mean pay-off) and total reward objectives as well as their combination. We consider this for Markov automata, a compositional model that captures both traditional Markov decision processes (MDPs) as well as a continuous-time variant thereof. The crux of our procedure is a generalization of Forejt et al.’s approach for total rewards on MDPs to arbitrary combinations of long-run and total reward objectives on Markov automata. Experiments with a prototypical implementation on top of the Storm model checker show encouraging results for both model types and indicate a substantial improved performance over existing multi-objective long-run MDP model checking based on linear programming.
Iterative Bounded Synthesis for Efficient Cycle Detection in Parametric Timed Automata
Authors: André Étienne , Arias Jaime , Petrucci Laure , Pol Jaco van de
Published: March 2021

We study semi-algorithms to synthesise the constraints under which a Parametric Timed Automaton satisfies some liveness requirement. The algorithms traverse a possibly infinite parametric zone graph, searching for accepting cycles. We provide new search and pruning algorithms, leading to successful termination for many examples. We demonstrate the success and efficiency of these algorithms on a benchmark. We also illustrate parameter synthesis for the classical Bounded Retransmission Protocol. Finally, we introduce a new notion of completeness in the limit, to investigate if an algorithm enumerates all solutions.
Synthesizing Context-free Grammars from Recurrent Neural Networks
Authors: Yellin Daniel M. , Weiss Gail
Published: March 2021

We present an algorithm for extracting a subclass of the context free grammars (CFGs) from a trained recurrent neural network (RNN). We develop a new framework,pattern rule sets(PRSs), which describe sequences of deterministic finite automata (DFAs) that approximate a non-regular language. We present an algorithm for recovering the PRS behind a sequence of such automata, and apply it to the sequences of automata extracted from trained RNNs using the$$L^{*}$$L∗algorithm. We then show how the PRS may converted into a CFG, enabling a familiar and useful presentation of the learned language.

Extracting the learned language of an RNN is important to facilitate understanding of the RNN and to verify its correctness. Furthermore, the extracted CFG can augment the RNN in classifying correct sentences, as the RNN’s predictive accuracy decreases when the recursion depth and distance between matching delimiters of its input sequences increases.
Automated and Formal Synthesis of Neural Barrier Certificates for Dynamical Models
Authors: Peruffo Andrea , Ahmed Daniele , Abate Alessandro
Published: March 2021

We introduce an automated, formal, counterexample-based approach to synthesise Barrier Certificates (BC) for the safety verification of continuous and hybrid dynamical models. The approach is underpinned by an inductive framework: this is structured as a sequential loop between a learner, which manipulates a candidate BC structured as a neural network, and a sound verifier, which either certifies the candidate’s validity or generates counter-examples to further guide the learner. We compare the approach against state-of-the-art techniques, over polynomial and non-polynomial dynamical models: the outcomes show that we can synthesise sound BCs up to two orders of magnitude faster, with in particular a stark speedup on the verification engine (up to three orders less), whilst needing a far smaller data set (up to three orders less) for the learning part. Beyond improvements over the state of the art, we further challenge the new approach on a hybrid dynamical model and on larger-dimensional models, and showcase the numerical robustness of our algorithms and codebase.
Counterexample-Guided Prophecy for Model Checking Modulo the Theory of Arrays
Authors: Mann Makai , Irfan Ahmed , Griggio Alberto , Padon Oded , Barrett Clark
Published: March 2021

We develop a framework for model checking infinite-state systems by automatically augmenting them with auxiliary variables, enabling quantifier-free induction proofs for systems that would otherwise require quantified invariants. We combine this mechanism with a counterexample-guided abstraction refinement scheme for the theory of arrays. Our framework can thus, in many cases, reduce inductive reasoning with quantifiers and arrays to quantifier-free and array-free reasoning. We evaluate the approach on a wide set of benchmarks from the literature. The results show that our implementation often outperforms state-of-the-art tools, demonstrating its practical potential.
SAT Solving with GPU Accelerated Inprocessing
Authors: Osama Muhammad , Wijs Anton , Biere Armin
Published: March 2021

Since 2013, the leading SAT solvers in the SAT competition all use inprocessing, which unlike preprocessing, interleaves search with simplifications. However, applying inprocessing frequently can still be a bottle neck, i.e., for hard or large formulas. In this work, we introduce the first attempt to parallelize inprocessing on GPU architectures. As memory is a scarce resource in GPUs, we present new space-efficient data structures and devise a data-parallel garbage collector. It runs in parallel on the GPU to reduce memory consumption and improves memory access locality. Our new parallel variable elimination algorithm is twice as fast as previous work. In experiments our new solver ParaFROST solves many benchmarks faster on the GPU than its sequential counterparts.
Spielplangestaltung im Kampf um Anerkennung – Diversifizierung als Legitimationsstrategie
Authors: Michaels Bianca
Published: March 2021

Deutschlandweit lässt sich seit einigen Jahren eine kontinuierlich steigende Zahl an neuen Veranstaltungsformen und -formaten außerhalb etablierter Genre- und Spartenbezeichnungen an öffentlich getragenen Theatern beobachten. Besonders ausgeprägt ist diese Tendenz zur Diversifizierung in der Spielplangestaltung der Münchner Kammerspiele seit der Spielzeit 2015/2016. Ziel des Beitrags ist die Untersuchung des Zusammenhangs von Spielplangestaltung und Legitimationsdiskursen am Beispiel der Kontroverse um die Münchner Kammerspiele unter der Intendanz von Matthias Lilienthal 2018.
Einführung in die Thematik: Zwischen Aushandlung und Direktive – Kulturpolitische Steuerungsmodelle und Theater
Authors: Siegmund Gerald
Published: March 2021

„Nie hat Politik so permanent und mächtig in den aktuellen Prozess des Kunst- und Kulturschaffens hineingewirkt wie im Augenblick“, schreibt Thomas Oberender, Intendant der Berliner Festspiele, in einem Beitrag zu einem Sammelband über „kulturpolitische Konzeptionen zur Reform der Darstellenden Künste“. Folgen wir Oberenders These, so ergibt sich daraus ein latentes Spannungsverhältnis zwischen Politik und den Theatern, deren Freiheit Politik doch gewährleisten soll. Garantiert Artikel 5 des Grundgesetzes die Kunstfreiheit, dürfte sich Kulturpolitik eigentlich gar nicht in den „Prozess des Kunst- und Kulturschaffens“ einmischen, respektive in diesen hineinwirken.
Kulturpolitische Steuerung. Entwicklung und Praxis am Beispiel öffentlich getragener Theater
Authors: Crückeberg Johannes , Steinhauer Moritz
Published: March 2021

Der Beitrag beschreibt die Entwicklung kulturpolitischer Steuerung von der klassisch-bürokratischen Verwaltung über das Neue Steuerungsmodell hin zur New Public Governance und zeigt anhand von Fallbeispielen ausgewählter Theater die Umsetzung dieser Modelle. Die explorative Analyse offenbart dabei hybride Steuerungsformen, welche Elemente der drei vorgestellten Konzepte integrieren sowie ein Auseinanderfallen von formalen Vorgaben und gelebter Praxis. Resümierend werden drei aus der Analyse abgeleitete Steuerungspraktiken vorgestellt: hierarchische, abwesende und kooperative Steuerung sowie Chancen und Risiken von kulturpolitischen Eingriffen durch Steuerungsmodelle diskutiert.
Zwischen Bedingung und Freiheit – Über die Zusammenarbeit zwischen Theaterbetrieben und ihren Aufsichtsgremien
Authors: Glesner Julia
Published: March 2021

Der Erfolg von Theaterbetrieben hängt auch davon ab, wie erfolgreich die Zusammenarbeit zwischen der Leitung und den aufsichtsführenden Gremien des Betriebs abläuft. Abhängig von den wichtigsten Rechtsformen von Theaterbetrieben in der BRD – GmbH, Eigenbetrieb und Regiebetrieb – kommen den Parteien unterschiedliche Entscheidungs- und Einflussmöglichkeiten zu. Durch unzureichendes Gremienmanagement oder wenn das aufsichtsführende Gremium seine Verantwortung nicht in vollem Umfang übernimmt, geraten die Betriebe in Krisen mit Folgen, die auch die Zukunft des Modells „Stadttheater“ gefährden.
Kulturbetrieb als Schlangengrube? – Kulturpolitische Steuerung de facto und de jure anhand der ‚Causa Binder‘
Authors: Hartung Ulrike
Published: March 2021

Kulturpolitische Steuerung im Kontext öffentlich getragener Theater in Deutschland findet überwiegend im Verborgenen statt. Findungsprozesse, in denen folgenreiche Entscheidungen wie Besetzungsverfahren verhandelt werden, sind außerhalb der Entscheidungsgremien selbst nur schwer nachzuvollziehen. Diese Intransparenz scheint jedoch immer erst dann die Aufmerksamkeit der Öffentlichkeit auf sich zu ziehen, wenn die Dysfunktionalität eines solchen Prozesses in öffentlicher Weise, wie z. B. in Form eines Rechtsstreits beteiligter Akteure augenscheinlich wird. Es handelt sich dabei nicht um ein spartenspezifisches Problem, sondern betrifft das Schauspiel ebenso wie die Oper und das Tanztheater, wie anhand konkreter Fälle exemplifiziert werden soll. Die ‚Causa Binder‘, wie der öffentliche Diskurs die Rechtsstreitigkeiten um Adolphe Binders Position als Intendantin des Tanztheaters Wuppertal übertitelt, ist ein besonders eindrucksvolles Beispiel für das Spannungsverhältnis zwischen kulturpolitischer Steuerung de jure und ihrer faktischen Umsetzung in institutioneller Praxis.
Das öffentlich geförderte Theater in der Legitimationskrise und unter Innovationsdruck? Ergebnisse einer repräsentativen Bevölkerungsbefragung
Authors: Mandel Birgit
Published: March 2021

Die Stadt- und Staatstheater als die am höchsten geförderten Kultureinrichtungen in Deutschland stehen in besonderer Weise unter Legitimationsdruck und benötigen ausreichend Rückhalt bei relevanten Stakeholdern, bei Publikum und in der Bevölkerung. Welches Interesse an Theatern und welche Einstellungen zu deren Aufgaben und deren öffentlicher Förderung gibt es in der Bevölkerung in Deutschland? Der Artikel präsentiert und diskutiert die Ergebnisse einer repräsentativen Bevölkerungsbefragung, die zeigt, dass zwar nur wenige zu den regelmäßigen Besucher*innen von Theatern gehören – darunter eher hoch gebildete, eher ältere und eher weibliche Personen – eine große Bevölkerungsmehrheit sich jedoch für eine weiterhin hohe öffentliche Förderung ausspricht. Von den Theatern werden vor allem eine hohe Zugänglichkeit sowie Programme kultureller Bildung für Kinder und Jugendliche erwartet. Die hohe Zustimmung zur Theaterförderung, weit über den Kreis des Publikums hinaus, verweist auf die hohe gesellschaftliche Bedeutung, die den Theatern zugeschrieben wird. Zugleich deuten sich erste Risse dieses positiven Theaterbildes bei den jüngeren Generationen an.
Theaterpolitik als Kulturpolitik
Authors: Fuchs Max
Published: March 2021

Theaterpolitik ist ein Teil der Kulturpolitik. Das heißt, dass man Strukturmerkmale der Kulturpolitik auf die Theaterpolitik übertragen kann. Das gilt insbesondere für den Governance-Ansatz. Hierbei geht es darum, dass man die verschiedensten Akteure bei der Politikgestaltung – und dies auf den unterschiedlichen Ebenen (Kommune, Land, Bund, Europäische Union, UNESCO) und in den unterschiedlichen Politikfeldern (neben Kulturpolitik sind es Rechtspolitik, Sozialpolitik, Wirtschaftspolitik, Kommunalpolitik etc.) – unterscheiden kann. Selbst eine grobe Sichtung dieser Vielfalt an Zugangsmöglichkeiten zeigt, dass man mit sehr unterschiedlichen Verständnis- und Begründungsweisen von Kulturpolitik rechnen muss.
Krisendiskurse in der Freien Theaterszene (Berlin): Kunst als soziales Wirksamkeitsversprechen im Spannungsfeld zwischen kulturpolitischer Steuerung und künstlerischer Selbstlegitimierung
Authors: Quickert Anja
Published: March 2021

In den vergangenen Jahren hat sich die Freie Theaterszene verstärkt mit Fragen der (Selbst-)Legitimierung ihrer künstlerischen Arbeit im Rahmen der strukturellen wie institutionellen Voraussetzungen auseinandergesetzt. Dabei wurde auch der moderne Autonomiebegriff der Kunst nachhaltig infrage gestellt zugunsten einer sozialen Wirksamkeit künstlerischer Praxis. Der folgende Beitrag bildet die diskursiven Positionen dieser künstlerischen Debatte ab, verortet sie in ihrem kunsthistorischen wie gesellschaftlichen Zusammenhang und fragt, welche Funktion die dazugehörigen Krisendiskurse für die (Selbst-)Legitimation der Freien Theaterszene im Kontext öffentlicher Kulturförderung besitzen.
Studie 3: Latente Berufswahlkompetenzprofile an weiterführenden allgemeinbildenden Schulen
Authors: Ohlemann Svenja
Published: March 2021

Aufgrund von externen Deadlines müssen Jugendliche am Ende ihrer Schulzeit erste berufswahlbezogene Entscheidungen treffen, während sie gleichzeitig verschiedene kognitive, körperliche und sozioemotionale Entwicklungsprozesse und Aufgaben zu bewältigen haben. Um eine informierte, proaktive Berufswahl treffen zu können, benötigen Jugendliche sowohl berufswahlrelevantes Wissen und Kompetenzen wie Selbstwissen, Kenntnisse der Arbeitswelt, Planungsfähigkeiten, Selbstvertrauen und Entschlossenheit, also auch die Motivation und den Willen zum Handeln.
Studie 4: Berufswahlkompetenzentwicklung an weiterführenden allgemeinbildenden Schulen: Eine latente Transitionsanalyse
Authors: Ohlemann Svenja
Published: March 2021

In Deutschland fühlen sich Schüler*innen an allgemeinbildenden Schulen auf dem Weg zum Abitur oftmals noch nicht ausreichend vorbereitet, um für ihre berufliche Zukunft konkrete Pläne zu entwickeln oder eine diesbezügliche Entscheidung zu treffen. In mehr als einem Viertel der Fälle fehlen ausreichende Informationen zu Studien- und Ausbildungsmöglichkeiten, um eine Entscheidung zu treffen, mit der sich die Heranwachsenden wohlfühlen.
Modelle differenzierter beruflicher Entwicklung
Authors: Ohlemann Svenja
Published: March 2021

Um den Erkenntnisstand zu individuellen Bedarfen Jugendlicher in ihrer beruflichen Orientierung zu erweitern – eine wesentliche Intention dieser Arbeit –, bedarf es einer ausdifferenzierteren Betrachtung des Entwicklungsprozesses. In diesem Kapitel werden daher ausgewählte theoretische Modelle vorgestellt, die die berufliche Orientierung in differenzierbare Stadien bzw. Phasen unterteilen, um allgemeingültige Prozesse beruflicher Entwicklung abzubilden.
Berufswahlrelevante Ressourcen und Kompetenzen
Authors: Ohlemann Svenja
Published: March 2021

Im vorangegangenen Kapitel 4 wurde anhand der erläuterten Modelle deutlich, dass Jugendliche zur erfolgreichen Bewältigung phasentypischer, berufswahlbezogener Aufgaben berufswahlrelevante Kompetenzen benötigen.
Methodisches Vorgehen
Authors: Ohlemann Svenja
Published: March 2021

Die vorliegende Arbeit nutzt Daten aus drei Forschungsprojekten und verbindet in der Untersuchung individueller Bedarfe und beruflicher Entwicklung querschnittliche und längsschnittliche Analysedesigns miteinander. Im Folgenden sollen die drei Forschungsprojekte mit den jeweiligen Zielen kurz vorgestellt werden. Tabelle 8.1 gibt einen Überblick über die vier in dieser Arbeit vorgestellten empirischen Studien, ihre Datengrundlagen, die jeweiligen Stichprobengrößen und -zusammensetzungen, sowie der Publikationsstatus.
Subcriticality
Authors: Hashimoto Kengo
Published: March 2021

For a subcritical reactor system driven by a periodically pulsed spallation neutron source in KUCA, the Feynman-α and the Rossi-α neutron correlation analyses are conducted to determine the prompt neutron decay constant and quantitatively to confirm a non-Poisson character of the neutron source. The decay constant determined from the present Feynman-α analysis well agrees with that from a previous analysis for the same subcritical system driven by an inherent source. Considering the effect of a higher mode excited, the disagreement can be successfully resolved. The power spectral analysis on frequency domain is also carried out. Not only the cross-power but also the auto-power spectral density have a considerable correlated component even at a deeply subcritical state, where no correlated component could be previously observed under a 14 MeV neutron source. The indicator of the non-Poisson character of the present spallation source can be obtained from the spectral analysis and is consistent with that from the Rossi-α analysis. An experimental technique based on an accelerator-beam trip or restart operation is proposed to determine the subcritical reactivity of ADS. Applying the least-squares inverse kinetics method to the data analysis, the subcriticality can be inferred from time-sequence neutron count data after these operations.
Searching for gauge theories with the conformal bootstrap
Authors: Li Zhijin , Poland David
Published: March 2021

Abstract

Infrared fixed points of gauge theories provide intriguing targets for the modern conformal bootstrap program. In this work we provide some preliminary evidence that a family of gauged fermionic CFTs saturate bootstrap bounds and can potentially be solved with the conformal bootstrap. We start by considering the bootstrap for SO(N) vector 4-point functions in general dimension D. In the large N limit, upper bounds on the scaling dimensions of the lowest SO(N) singlet and traceless symmetric scalars interpolate between two solutions at ∆ = D/2 − 1 and ∆ = D − 1 via generalized free field theory. In 3D the critical O(N) vector models are known to saturate the bootstrap bounds and correspond to the kinks approaching ∆ = 1/2 at large N. We show that the bootstrap bounds also admit another infinite family of kinks $$ {\mathcal{T}}_D $$

T
D

, which at large N approach solutions containing free fermion bilinears at ∆ = D − 1 from below. The kinks $$ {\mathcal{T}}_D $$

T
D

appear in general dimensions with a D-dependent critical N* below which the kink disappears. We also study relations between the bounds obtained from the bootstrap with SO(N) vectors, SU(N) fundamentals, and SU(N) × SU(N) bi-fundamentals. We provide a proof for the coincidence between bootstrap bounds with different global symmetries. We show evidence that the proper symmetries of the underlying theories of $$ {\mathcal{T}}_D $$

T
D

are subgroups of SO(N), and we speculate that the kinks $$ {\mathcal{T}}_D $$

T
D

relate to the fixed points of gauge theories coupled to fermions.
Kinetic mixing, dark photons and extra dimensions. Part III. Brane localized dark matter
Authors: Rizzo Thomas G. , Wojcik George N.
Published: March 2021

Abstract

Extra dimensions have proven to be a very useful tool in constructing new physics models. In earlier work, we began investigating toy models for the 5-D analog of the kinetic mixing/vector portal scenario where the interactions of dark matter, taken to be, e.g., a complex scalar, with the brane-localized fields of the Standard Model (SM) are mediated by a massive U(1)D dark photon living in the bulk. These models were shown to have many novel features differentiating them from their 4-D analogs and which, in several cases, avoided some well-known 4-D model building constraints. However, these gains were obtained at the cost of the introduction of a fair amount of model complexity, e.g., dark matter Kaluza-Klein excitations. In the present paper, we consider an alternative setup wherein the dark matter and the dark Higgs, responsible for U(1)D breaking, are both localized to the ‘dark’ brane at the opposite end of the 5-D interval from where the SM fields are located with only the dark photon now being a 5-D field. The phenomenology of such a setup is explored for both flat and warped extra dimensions and compared to the previous more complex models.
Partition functions of the tensionless string
Authors: Eberhardt Lorenz
Published: March 2021

Abstract

We consider string theory on AdS3× S3× 𝕋4 in the tensionless limit, with one unit of NS-NS flux. This theory is conjectured to describe the symmetric product orbifold CFT. We consider the string on different Euclidean backgrounds such as thermal AdS3, the BTZ black hole, conical defects and wormhole geometries. In simple examples we compute the full string partition function. We find it to be independent of the precise bulk geometry, but only dependent on the geometry of the conformal boundary. For example, the string partition function on thermal AdS3 and the conical defect with a torus boundary is shown to agree, thus giving evidence for the equivalence of the tensionless string on these different background geometries. We also find that thermal AdS3 and the BTZ black hole are dual descriptions and the vacuum of the BTZ black hole is mapped to a single long string winding many times asymptotically around thermal AdS3. Thus the system yields a concrete example of the string-black hole transition. Consequently, reproducing the boundary partition function does not require a sum over bulk geometries, but rather agrees with the string partition function on any bulk geometry with the appropriate boundary. We argue that the same mechanism can lead to a resolution of the factorization problem when geometries with disconnected boundaries are considered, since the connected and disconnected geometries give the same contribution and we do not have to include them separately.
Leptonic sum rules from flavour models with modular symmetries
Authors: Gehrlein J. , Spinrath M.
Published: March 2021

Abstract

Sum rules in the lepton sector provide an extremely valuable tool to classify flavour models in terms of relations between neutrino masses and mixing parameters testable in a plethora of experiments. In this manuscript we identify new leptonic sum rules arising in models with modular symmetries with residual symmetries. These models simultaneously present neutrino mass sum rules, involving masses and Majorana phases, and mixing sum rules, connecting the mixing angles and the Dirac CP-violating phase. The simultaneous appearance of both types of sum rules leads to some non-trivial interplay, for instance, the allowed absolute neutrino mass scale exhibits a dependence on the Dirac CP-violating phase. We derive analytical expressions for these novel sum rules and present their allowed parameter ranges as well as their predictions at upcoming neutrino experiments.
Generalised superconformal higher-spin multiplets
Authors: Kuzenko Sergei M. , Ponds Michael , Raptakis Emmanouil S. N.
Published: March 2021

Abstract

We propose generalised $$ \mathcal{N} $$
N
= 1 superconformal higher-spin (SCHS) gauge multiplets of depth t, $$ {\Upsilon}_{\alpha (n)\overset{\cdot }{\alpha }(m)}^{(t)} $$

ϒ

α

n

α
⋅

m

t

, with n ≥ m ≥ 1. At the component level, for t > 2 they contain generalised conformal higher-spin (CHS) gauge fields with depths t − 1, t and t + 1. The supermultiplets with t = 1 and t = 2 include both ordinary and generalised CHS gauge fields. Super-Weyl and gauge invariant actions describing the dynamics of $$ {\Upsilon}_{\alpha (n)\overset{\cdot }{\alpha }(m)}^{(t)} $$

ϒ

α

n

α
⋅

m

t

on conformally-flat superspace backgrounds are then derived. For the case n = m = t = 1, corresponding to the maximal-depth conformal graviton supermultiplet, we extend this action to Bach-flat backgrounds. Models for superconformal non-gauge multiplets, which are expected to play an important role in the Bach-flat completions of the models for $$ {\Upsilon}_{\alpha (n)\overset{\cdot }{\alpha }(m)}^{(t)} $$

ϒ

α

n

α
⋅

m

t

, are also provided. Finally we show that, on Bach-flat backgrounds, requiring gauge and Weyl invariance does not always determine a model for a CHS field uniquely.
Dimensional reduction of higher-point conformal blocks
Authors: Hoback Sarah , Parikh Sarthak
Published: March 2021

Abstract

Recently, with the help of Parisi-Sourlas supersymmetry an intriguing relation was found expressing the four-point scalar conformal block of a (d −2)-dimensional CFT in terms of a five-term linear combination of blocks of ad-dimensional CFT, with constant coefficients. We extend this dimensional reduction relation to all higher-point scalar conformal blocks of arbitrary topology restricted to scalar exchanges. We show that the constant coefficients appearing in the finite term higher-point dimensional reduction obey an interesting factorization property allowing them to be determined in terms of certain graphical Feynman-like rules and the associated finite set of vertex and edge factors. Notably, these rules can be fully determined by considering the explicit power-series representation of just three particular conformal blocks: the four-point block, the five-point block and the six-point block of the so-called OPE/snowflake topology. In principle, this method can be applied to obtain the arbitrary-point dimensional reduction of conformal blocks with spinning exchanges as well. We also show how to systematically extend the dimensional reduction relation of conformal partial waves to higher-points.
Powder-based laser hybrid additive manufacturing of metals: a review
Authors: Jiménez Amaia , Bidare Prveen , Hassanin Hany , Tarlochan Faris , Dimov Stefan , Essa Khamis
Published: March 2021

Recent advances in additive manufacturing (AM) have attracted significant industrial interest. Initially, AM was mainly associated with the fabrication of prototypes, but the AM advances together with the broadening range of available materials, especially for producing metallic parts, have broaden the application areas and now the technology can be used for manufacturing functional parts, too. Especially, the AM technologies enable the creation of complex and topologically optimised geometries with internal cavities that were impossible to produce with traditional manufacturing processes. However, the tight geometrical tolerances along with the strict surface integrity requirements in aerospace, biomedical and automotive industries are not achievable in most cases with standalone AM technologies. Therefore, AM parts need extensive post-processing to ensure that their surface and dimensional requirements together with their respective mechanical properties are met. In this context, it is not surprising that the integration of AM with post-processing technologies into single and multi set-up processing solutions, commonly referred to as hybrid AM, has emerged as a very attractive proposition for industry while attracting a significant R&D interest. This paper reviews the current research and technology advances associated with the hybrid AM solutions. The special focus is on hybrid AM solutions that combine the capabilities of laser-based AM for processing powders with the necessary post-process technologies for producing metal parts with required accuracy, surface integrity and material properties. Commercially available hybrid AM systems that integrate laser-based AM with post-processing technologies are also reviewed together with their key application areas. Finally, the main challenges and open issues in broadening the industrial use of hybrid AM solutions are discussed.
Longitudinal changes in telomere length in PCB-exposed individuals: interaction with CMV infection
Authors: Beier Fabian , Esser Andre , Vankann Lucia , Abels Anne , Schettgen Thomas , Kraus Thomas , Brümmendorf Tim H. , Ziegler Patrick
Published: March 2021

We recently demonstrated a significant shortening of age-adapted telomere length (TL) in lymphocytes of polychlorinated biphenyls (PCB)-exposed individuals. Here, we analyzed TL in individuals of the same PCB-exposed cohort during a 6-year follow-up period, investigating the change in TL between the first and second measurement as a function of time, concentration of PCBs and cytomegalovirus (CMV) infection. The age-adjusted TL of lymphocytes within the cohort of PCB-exposed individuals recovered from a first assessment in 2011 to a second assessment in 2017. Remarkably, if the concentration of lower chlorinated PCBs (LC PCBs) in 2011 was high (≥ 0.055 µg/L), the TL of CMV seropositive individuals remained significantly shortened both compared to age-adjusted controls as well as intra individually. This was confirmed by analysis of covariance as well as by multivariate linear mixed effects models. Since telomeres are responsive to various stress response pathways, including viral infection, we conclude that PCBs could contribute to immune senescence-like phenotypes associated with CMV infections and exacerbate negative aspects associated with the aging of the immune system.
Efficacy and safety of anti-PD-1-based therapy in combination with PARP inhibitors for patients with advanced solid tumors in a real-world setting
Authors: Wu Zhaozhen , Tao Haitao , Zhang Sujie , Wang Xiao , Ma Junxun , Li Ruixin , Liu Zhefeng , Wang Jinliang , Cui Pengfei , Chen Shixue , Di Huang , Huang Ziwei , Zheng Xuan , Hu Yi
Published: March 2021

Background

Rationale exists for combining immune checkpoint inhibitors and PARP inhibitors (PARPi), and results of clinical trials in ovarian cancer are promising, but data in other cancers are limited.

Method

Efficacy and safety of PARPi/anti-PD-1 in advanced solid tumors were retrospectively analyzed. The efficacy measures included objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS).

Results

This retrospective study included data from 40 patients. The ORR was 27.5% (95% CI, 13.0–42.0%), with a DCR of 85.0% (95% CI, 73.4–96.6%). Except four patients in first-line treatment (three with PR and one with SD), the ORR of ≥second-line treatment, non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) was 22.2%, 23.1% and 28.6%, and the DCR was 83.3%, 84.6% and 71.4%, separately. The median PFS of all patients, ≥second-line treatment, NSCLC and SCLC was 4.6 m, 4.2 m, 4.5 m and 3.7 m. The median OS was 9.4 m, 11.4 m, 12.7 m and 5.4 m, respectively. Multivariable analysis revealed that BRCA1/2 mutation was positively correlated with ORR (P = 0.008), and LDH≥250U/L was negatively correlated with lowered DCR (P = 0.018), while lymphocyte number, ECOG and LDH significantly influenced both PFS and OS. We found that the possible resistant mechanisms were sarcomatous degeneration and secondary mutation, including BRCA2 truncation mutation, A2M, JAK1,T790M, KEAP1 and mTOR mutation. 37.5% patients had ≥grade 3 adverse events.

Conclusion

PARPi/anti-PD-1 is an effective and tolerable method for patients with advanced solid tumors, and BRCA1/2 is a potential biomarker.
Development of a Rapid Intraoperative Point‐of‐Care Method Using Tissue Suspension to Differentiate Parathyroid Tissue: A Possible Substitute for Frozen Sections
Authors: Kikumori Toyone , Shibata Masahiro , Takeuchi Dai
Published: March 2021

Background

We reported that aspartate aminotransferase (AST)/lactate dehydrogenase (LDH) ratio of a tissue suspension can precisely differentiate normal and hyperfunctioning parathyroid tissue (PT) from other tissues. However, in these studies, LDH and AST were measured using the standard method for blood samples, with a turnaround time of approximately 1 h, hampering clinical application. Here, we developed a rapid and robust method to differentiate PT instead of using frozen sections.

Methods

Excised specimens from 28 patients (n = 69) who underwent thyroid or parathyroid surgery between October 2019 and April 2020 were analyzed. AST and LDH were measured in suspensions of PT or other tissues, using both the standard method in the in‐facility laboratory and a point‐of‐care testing device (NX500, Fujifilm, Japan).

Results and conclusions

A good correlation was found between the standard method and NX500 for AST and LDH levels >10 IU/L. In the analyses using 52 specimens with ≥ 10 IU/L of both AST and LDH measured using the NX500, PT was distinguished with 100% sensitivity and specificity using an optimal cutoff AST/LDH ratio of 0.48. The turnaround time was estimated to be less than 10 min. This method could be a cost‐ and labor‐effective alternative to frozen sections to reduce the incidence of postoperative hypoparathyroidism and improve the outcome of primary hyperparathyroidism in low‐resource areas.
Correction to: Self‐management Behaviors and Anthropometric Indices after Roux‐en‐Y Gastric Bypass
Authors: Sobhani Zahra , Amini Masood , Zarnaghash Maryam , Foroutan Hamid Reza , Mojab Seyed Vahid , Khazraei Hajar , Hosseini Seyed Vahid
Published: March 2021

A correction to this paper has been published: https://doi.org/10.1007/s00268‐021‐06069‐5
Transkorneale Elektrostimulation bei Retinitis pigmentosa
Authors:   retina.net e. V., Kahle Nadine ,   TES-RP-Studiengruppe, Peters Tobias , Braun Angelika , Franklin Jeremy , Michalik Claudia , Gekeler Florian , Wilhelm Barbara
Published: March 2021

Der Schwerpunkt dieser großen, multizentrischen Erprobungsstudie im Auftrag des Gemeinsamen Bundesausschusses (G-BA) liegt in der Feststellung eines Nutzens der transkornealen Elektrostimulation für Patienten mit Retinitis pigmentosa (RP). Hauptkriterium ist das kinetische Gesichtsfeld und die Frage, ob die Verschlechterung der Studienaugen im Vergleich zu den zum Schein (sham‑)stimulierten Partneraugen über einen Behandlungszeitraum von 3 Jahren langsamer fortschreitet.
Finite element analysis of bone remodelling with piezoelectric effects using an open-source framework
Authors: Bansod Yogesh Deepak , Kebbach Maeruan , Kluess Daniel , Bader Rainer , van Rienen Ursula
Published: March 2021

Bone tissue exhibits piezoelectric properties and thus is capable of transforming mechanical stress into electrical potential. Piezoelectricity has been shown to play a vital role in bone adaptation and remodelling processes. Therefore, to better understand the interplay between mechanical and electrical stimulation during these processes, strain-adaptive bone remodelling models without and with considering the piezoelectric effect were simulated using the Python-based open-source software framework. To discretise numerical attributes, the finite element method (FEM) was used for the spatial variables and an explicit Euler scheme for the temporal derivatives. The predicted bone apparent density distributions were qualitatively and quantitatively evaluated against the radiographic scan of a human proximal femur and the bone apparent density calculated using a bone mineral density (BMD) calibration phantom, respectively. Additionally, the effect of the initial bone density on the resulting predicted density distribution was investigated globally and locally. The simulation results showed that the electrically stimulated bone surface enhanced bone deposition and these are in good agreement with previous findings from the literature. Moreover, mechanical stimuli due to daily physical activities could be supported by therapeutic electrical stimulation to reduce bone loss in case of physical impairment or osteoporosis. The bone remodelling algorithm implemented using an open-source software framework facilitates easy accessibility and reproducibility of finite element analysis made.
Enzymatic biofilm destabilisation to support mechanical cleansing of inserted dental implant surfaces: an in-vitro pilot study
Authors: Matthes Rutger , Jablonowski Lukasz , Holtfreter Birte , Pink Christiane , Kocher Thomas
Published: March 2021

Peri-implantitis is caused by microbial contamination and biofilm formation on the implant surface. To achieve re-osseointegration, the microbes must be completely removed from the surface. Adjunctive to mechanical cleaning, chemical treatment with enzymes or other substances could optimise the treatment outcome. Therefore, we investigated the efficacy of different enzymes, a surfactant, and a chelator in destabilising dental polymicrobial biofilm. The biofilm destabilising effect of the glycosidases α-amylase, dextranase, DispersinB®, and lysozyme, as well as the proteinase subtilisin A, and the nuclease Benzonase®, the chelator EDTA, and the surfactant cocamidopropyl betaine were investigated on biofilms, inoculated with plaque on rough titanium discs. The test and the control solutions were incubated for 15 min at 36 °C on biofilms, and loosened biofilm mass was removed by shear stress with a shaker. Fluorescence-stained biofilms were microscopically analysed. Acceptable cell tolerability concentrations of test substances were determined by the MTT (tetrazolium dye) assay on the MG-63 cell line. A statistically significant biofilm destabilising effect of 10% was shown with lysozyme (2500 µg/ml).
Recommendations for tilt table testing and other provocative cardiovascular autonomic tests in conditions that may cause transient loss of consciousness
Authors: Thijs Roland D. , Brignole Michele , Falup-Pecurariu Cristian , Fanciulli Alessandra , Freeman Roy , Guaraldi Pietro , Jordan Jens , Habek Mario , Hilz Max , Traon Anne Pavy-Le , Stankovic Iva , Struhal Walter , Sutton Richard , Wenning Gregor , Van Dijk J. Gert
Published: March 2021

An expert committee was formed to reach consensus on the use of tilt table testing (TTT) in the diagnosis of disorders that may cause transient loss of consciousness (TLOC) and to outline when other provocative cardiovascular autonomic tests are needed. While TTT adds to history taking, it cannot be a substitute for it. An abnormal TTT result is most meaningful if the provoked event is recognised by patients or eyewitnesses as similar to spontaneous events. The minimum requirements to perform TTT are a tilt table, a continuous beat-to-beat blood pressure monitor, at least one ECG lead, protocols for the indications stated below and trained staff. This basic equipment lends itself to the performance of (1) additional provocation tests, such as the active standing test, carotid sinus massage and autonomic function tests; (2) additional measurements, such as video, EEG, transcranial Doppler, NIRS, end-tidal CO2 or neuro-endocrine tests; and (3) tailor-made provocation procedures in those with a specific and consistent trigger of TLOC. TTT and other provocative cardiovascular autonomic tests are indicated if the initial evaluation does not yield a definite or highly likely diagnosis, but raises a suspicion of (1) reflex syncope, (2) the three forms of orthostatic hypotension (OH), i.e. initial, classic and delayed OH, as well as delayed orthostatic blood pressure recovery, (3) postural orthostatic tachycardia syndrome or (4) psychogenic pseudosyncope. A therapeutic indication for TTT is to teach patients with reflex syncope and OH to recognise hypotensive symptoms and to perform physical counter manoeuvres.
Dual sequentially addressable dielectrophoretic array for high-throughput, scalable, multiplexed droplet sorting
Authors: Isozaki Akihiro , Huang Dunhou , Nakagawa Yuta , Goda Keisuke
Published: March 2021

Droplet microfluidics is a powerful tool for a diverse range of biomedical and industrial applications such as single-cell biology, synthetic biology, digital PCR, biosafety monitoring, drug screening, and food, feed, and cosmetic industries. As an integral part of droplet microfluidics, on-chip multiplexed droplet sorting has recently gained enthusiasm, since it enables real-time sorting of single droplets containing cells with different phenotypes into multiple bins. However, conventional sorting methods are limited in throughput and scalability. Here, we present high-throughput, scalable, multiplexed droplet sorting by employing a pair of sequentially addressable dielectrophoretic arrays (SADAs) across a microchannel on a microfluidic chip. A SADA is an on-chip array of electrodes, each of which is sequentially activated and deactivated in synchronization to the position and speed of a flowing droplet of interest. The dual-SADA (dSADA) structure enables high-throughput deflection of droplets in multiple directions in a well-controlled manner. For proof-of-concept demonstration and characterization of the dSADA, we performed fluorescence-activated droplet sorting (FADS) with a 3-way dSADA at a high throughput of 2450 droplets/s. Furthermore, to show the scalability of the dSADA, we also performed FADS with a 5-way dSADA at a high throughput of 473 droplets/s.
Lyapunov stability of competitive cells dynamics in tumor mechanobiology
Authors: Carotenuto Angelo Rosario , Cutolo Arsenio , Palumbo Stefania , Fraldi Massimiliano
Published: March 2021

Poromechanics plays a key role in modelling hard and soft tissue behaviours, by providing a thermodynamic framework in which chemo-mechanical mutual interactions among fluid and solid constituents can be consistently rooted, at different scale levels. In this context, how different biological species (including cells, extra-cellular components and chemical metabolites) interplay within complex environments is studied for characterizing the mechanobiology of tumor growth, governed by intratumoral residual stresses that initiate mechanotransductive processes deregulating normal tissue homeostasis and leading to tissue remodelling. Despite the coupling between tumor poroelasticity and interspecific competitive dynamics has recently highlighted how microscopic cells and environment interactions influence growth-associated stresses and tumor pathophysiology, the nonlinear interlacing among biochemical factors and mechanics somehow hindered the possibility of gaining qualitative insights into cells dynamics. Motivated by this, in the present work we recover the linear poroelasticity in order to benefit of a reduced complexity, so first deriving the well-known Lyapunov stability criterion from the thermodynamic dissipation principle and then analysing the stability of the mechanical competition among cells fighting for common space and resources during cancer growth and invasion. At the end, the linear poroelastic model enriched by interspecific dynamics is also exploited to show how growth anisotropy can alter the stress field in spherical tumor masses, by thus indirectly affecting cell mechano-sensing.

GraphicAbstract
Diffusion and reaction in pore hierarchies by the two-region model
Authors: Hwang Seungtaik , Kärger Jörg , Miersemann Erich
Published: March 2021

The two-region (“Kärger”) model of diffusion in complex pore spaces is exploited for quantitating mass transfer in hierarchically organized nanoporous materials, consisting of a continuous microporous bulk phase permeated by a network of transport pores. With the implications that the diffusivity in the transport pores significantly exceeds the diffusivity in the micropores and that the relative population of the transport pores is far below that of the micropores, overall transport depends on only three independent parameters. Depending on their interrelation, enhancement of the overall mass transfer is found to be ensured by two fundamentally different mechanisms. They are referred to as the limiting cases of fast and slow exchange, with the respective time constants of molecular uptake being controlled by different parameters. Complemented with reaction terms, the two-region model may equally successfully be applied to the quantitation of the combined effect of diffusion and reaction in terms of the effectiveness factor. Generalization of the classical Thiele concept is shown to provide an excellent estimate of the effectiveness factor of a chemical reaction in hierarchically porous materials, solely based on the intrinsic reaction rate and the time constant of molecular uptake relevant to the given conditions.
The alien flora of Sudan and South Sudan: taxonomic and biogeographical composition
Authors: Omer Ali , Kordofani Maha , Gibreel Haytham H. , Pyšek Petr , van Kleunen Mark
Published: March 2021

Studies on plant invasions depend on local and regional checklists of the alien flora. However, global overview studies have shown that some regions, including many African countries, remain understudied in this regard. To contribute to filling this gap, here we present the first checklist of alien plants of Sudan and South Sudan (the Sudans). We analysed the taxonomic and geographical composition of the species on this list. Our result show that of the 113 alien species in Sudans (99 in Sudan and 59 in South Sudan), 92 (81.4%) are naturalized and 21 (18.6%) are just casual aliens. The number of naturalized species represent 2.2% of the total flora of the Sudans (4096). The alien species belong to 44 families and 85 genera, and many of them are native to Southern America and Northern America (85.8%). Annual and perennial herbs are the prevailing life forms in the alien flora of the Sudans (68.1%), and, among the casual species, perennial herbs are underrepresented whereas woody tree species are over-represented. Alien plants of the Sudans are mostly used for medicinal and environmental purposes globally. The naturalized plants predominantly occur in man-made disturbed habitats, such as agricultural and ruderal habitats. This first overview of the alien flora of the Sudans should stimulate further research and recording of the alien flora to better understand the drivers and consequences of alien plants in the Sudans.
Risk assessment in deferred and recovered donors
Authors: Heck Ellen , Corder Valerie , Urban Jill , Petroll Matthew , Timmons William , Cavanaugh Dwight
Published: March 2021

Serologic testing and Donor Risk Assessment Interview (DRAI) combined have made tissue transplantation a frequent and safe modality for a variety of trauma and disease conditions. Donate Life America reports 30,000 tissue donors providing more than 1,750,000 tissue transplants annually. This study of 188 potential donor cases addresses issues of risk assessment in a medical examiner population in a metropolitan area, where serologic testing of deferred potential donors were compared with the DRAI screening, which determined the suitability or non-suitability for tissue procurement. Such serologic testing of deferred cases is not usually available in evaluating screening processes. This comparison gives insight into the effectiveness of the DRAI screening in deferring potential serology reactive donors. Results show in 65 cases how the DRAI screening eliminates most, but not all of the serologically reactive donors identified post recovery. The result emphasizes the need for the combined process of DRAI screening and testing to assure transplantation safety.