bluuebunny/crossref_metadata_2025 huggingface dataset:
Sparse Approximation of Multivariate Functions from Small Datasets Via Weighted Orthogonal Matching Pursuit
Authors: Adcock Ben , Brugiapaglia Simone
Published: August 2020

We show the potential of greedy recovery strategies for the sparse approximation of multivariate functions from a small dataset of pointwise evaluations by considering an extension of the orthogonal matching pursuit to the setting of weighted sparsity. The proposed recovery strategy is based on a formal derivation of the greedy index selection rule. Numerical experiments show that the proposed weighted orthogonal matching pursuit algorithm is able to reach accuracy levels similar to those of weightedℓ1minimization programs while considerably improving the computational efficiency for small values of the sparsity level.
An Adaptive Error Inhibiting Block One-Step Method for Ordinary Differential Equations
Authors: Gu Jiaxi , Jung Jae-Hun
Published: August 2020

An explicit error inhibiting block one-step method was developed by Ditkowski and Gottlieb in 2017. It is motivated by a class of one-step methods described in Shampine and Watts (Math Comp 23:731–740, 1969), which takes initial s step values to generate the next s step values at each step. The error inhibiting method shares the form of the diagonally implicit multistage integration method of type 3 introduced in Butcher (Appl Numer Math 11:347–363, 1993). With the explicit error inhibiting scheme, the convergence of the global error is one order higher than that of the local truncation error, while in general the global error decays with the same order as the local truncation error. In this work, we improve the explicit error inhibiting block one-step method in order to further enhance the convergence and accuracy of the method. The main idea is to adopt the radial basis functions as a reconstruction basis replacing the polynomial basis. The numerical results confirm that the proposed method is efficient in providing enhanced order of accuracy.
Pirate Narratives and the Colonial Atlantic
Authors: Ganser Alexandra
Published: August 2020

This chapter examines the transformation of the Caribbean pirate into a colonial agent on the one hand and an enemy for Puritan society on the other around 1700. It begins with an analysis of Exquemelin’s Buccaneers of America (1678), which inspired a series of ethnographic narratives about the New World by former ‘pirates’ at the time (e.g., William Dampier, Basil Ringrose, Bartholomew Sharp, Lionel Wafer), written as evidence of their authors’ gradual transformation into scientists. They adopted the discourse of science and helped legitimize colonial plunder—material and symbolic—as beneficial to the European ‘empire of knowledge’. The second part focuses on gallows narratives and anti-piratical sermons in Puritan New England, which articulated piracy as sinful, devilish, and destructive for the community. Public executions of pirates and the sermons and broadsides produced for these events used the figure of the pirate as an Other against whom to produce and renew third-generation Puritan social cohesion. Cotton Mather’s and other ministers’ comments on piracy are read as a response to the perception of collective crisis of Puritan society.
Introduction: From Fundamentals to Advances in Crowdfunding Research and Practice
Authors: Shneor Rotem , Zhao Liang , Flåten Bjørn-Tore
Published: August 2020

The chapter introduces the phenomenon of crowdfunding while presenting its definition and main manifestations in recent years. It then discusses the roles played by the various parties to a crowdfunding transaction, as well as the benefits each may gain from such engagement. Overall, it argues for a win-win situation, where all parties become better off from involvement in a responsible crowdfunding engagement. Furthermore, the chapter highlights the process dimension of crowdfunding, as represented through a series of three main stages, which are further specified into a seven sub-stage model. Each stage in the process depends on successful completion of the stage preceding it and relates to concrete activities and considerations that should be taken at different points in time. The chapter concludes with a review of the chapter contributions included in this book and highlights their main contributions.
The FinTech Industry: Crowdfunding in Context
Authors: Griffiths Paul
Published: August 2020

This chapter presents how the financial services sector, especially banking, was a driver for ICT development in the last quarter of the twentieth century and early years of this century. But several phenomena happened on technological, social, and financial fronts in the second half of the last decade that led banks to ‘get their eyes off the ball’ and open the window for a whole new industrial sector to emerge, FinTech. This chapter analyses the phenomenon with the objective of answering: Why did FinTech emerge as an industrial sector, independent of banking? How is the FinTech industry organized and where does crowdfunding fit in? The chapter identifies three external forces that acted upon the banking system and created the conditions for the FinTech sector to emerge. It also looks at the FinTech sector from an industrial organization perspective and proposes a framework connecting financial services functionality and technological applications.
Crowdfunding in China: Turmoil of Global Leadership
Authors: Zhao Liang , Li Yuanqing
Published: August 2020

This chapter offers a comprehensive review and explanation of crowdfunding in China. It first extensively describes the status of crowdfunding in China by presenting the market facts, insights, and current regulations of the four main crowdfunding models (reward-based, equity-based, loan-based, and donation-based) respectively. Next, through a detailed up-to-date literature review of the key literature of Chinese crowdfunding, three main research streams are summarized and discussed covering success drivers, comparative studies of Chinese versus other contexts of crowdfunding practice, and applications of crowdfunding for creative and sustainability projects. Finally, both practical and research implications are presented together with the challenges and future research directions on crowdfunding in China.
Crowdfunding Sustainability
Authors: Maehle Natalia , Otte Pia Piroschka , Drozdova Natalia
Published: August 2020

The chapter focuses on using crowdfunding for financing sustainable projects, that is projects aiming to extend their goal beyond market success and provide benefit to the larger part of society. The chapter discusses the definition and dimensions of sustainable development and sustainable entrepreneurship and provides an overview of the existing literature on crowdfunding of sustainable projects. The authors also review four European sustainability-oriented crowdfunding platforms representing different crowdfunding models. This review reveals that sustainable projects have rather high success rates in crowdfunding and may address all the three dimensions of sustainable development. However, environmental dimension gets the most attention. All the crowdfunding models are relevant for sustainable projects; yet, Loan-based crowdfunding seems to have the highest success rates. Moreover, focus on a particular dimension of sustainability may influence the choice of the crowdfunding model.
Civic Crowdfunding: Four Perspectives on the Definition of Civic Crowdfunding
Authors: Wenzlaff Karsten
Published: August 2020

Civic Crowdfunding describes campaigns which aim to create a semi-public good. Unlike other crowdfunding practices, civic crowdfunding creates benefits for people outside of the group of supporters as well. This chapter analyses the literature on civic crowdfunding and proposes to view this increasing field of practice through four perspectives: the project, the supporter, the project owner, and the platform. The chapter argues that the platform is central to understanding the self-positioning of projects, supporters, and project owners within civic crowdfunding.
Crowdfunding Models, Strategies, and Choices Between Them
Authors: Shneor Rotem
Published: August 2020

The growing popularity of crowdfunding is manifested through the proliferation of thousands of platforms globally. The current chapter presents an elaborate, up-to-date, and detailed typology of crowdfunding models currently in use, as well as their main characteristics. Furthermore, it suggests some of the first frameworks developed for guiding prospective fundraisers in choosing between models. Each of the frameworks is designed for a different type of fundraiser, including model choice heuristics for organizations and consumers. The chapter concludes with some suggestions for further research and implications for practice.
Crowdfunding Education: Objectives, Content, Pedagogy, and Assessment
Authors: Shneor Rotem , Flåten Bjørn-Tore
Published: August 2020

Despite its rapid growth, little attention has been given to education and training in crowdfunding. Such training is important for ensuring the healthy and ethical development of the crowdfunding industry by educating the public about the challenges and risks as well as the merits and benefits of crowdfunding. While many may have heard the term ‘crowdfunding’, it often remains poorly understood by the larger public. Hence, this chapter argues the need for crowdfunding dedicated education programmes, while presenting a concrete course programme based on the Crowdfunding Lab developed at the University of Agder in Norway. The Crowdfunding Lab is to our knowledge one of the first university courses being offered and will thus provide unique insight. The course objectives, content, pedagogy, and assessment procedures are discussed, and opportunities for further developments are outlined. This chapter concludes with implications for educators, as well as with relevant suggestions for research.
Reward-Based Crowdfunding Research and Practice
Authors: Zhao Liang , Ryu Sunghan
Published: August 2020

This chapter offers a review of reward-based crowdfunding. Based on a concrete framework, this chapter extensively explains the definition, mechanisms, and unique aspects of reward-based crowdfunding. To better understand the status of reward-based crowdfunding from a global perspective, the development and regional characteristics of it in different crowdfunding markets are presented and discussed in this chapter. In addition, through a comprehensive literature review of key reward-based crowdfunding research, two main research streams of reward-based crowdfunding (success drivers and contributor behaviour) are summarized. Lastly, this chapter also sheds light on the implications of reward-based crowdfunding for practice and research, as well as mentions its potential contributions and limitations.
Lernzielorientierte Kurse
Authors: Derr Katja , Mechelke-Schwede Edith , Weigel Miriam
Published: August 2020

Die Struktur des mathematischen Curriculums des optes-Vorkurses (siehe Kapitel 13) findet sich im Aufbau und der Anordnung der Lerninhalte wieder. Jedes mathematische Themengebiet ist einem ILIAS-Kurs zugeordnet. Die Lerninhalte dieses Kurses wiederum wurden zu Lernzielen zusammengefasst, die den Lernenden helfen, sich im Vorkurs zurechtzufinden.
E-Tutoring
Authors: Mersch André , Seibt Alina
Published: August 2020

E-Learning bietet zahlreiche Möglichkeiten, die Präsenzlehre inhaltlich und didaktisch anzureichern und damit die Studienbedingungen zu verbessern. In der Praxis fehlt den Lehrenden jedoch oftmals der zeitliche Spielraum, um entsprechende Angebote zu erstellen. Das Konzept des E-Tutorings schafft hier Entlastung: E-Tutor* innen unterstützen Lehrende beim Einsatz digitaler Medien in der Gestaltung von Lehr-, Lern- und Prüfungsprozessen.
Nachhaltige Softwareentwicklungen im Verbundprojekt optes
Authors: Kunkel Matthias , Samoila Oliver
Published: August 2020

In Forschungs- und Entwicklungsprojekten mit E-Learning-Bezug wird gerne Open-Source-Software eingesetzt, weil diese leicht und kostengünstig Anpassungen an spezifische Projektanforderungen erlaubt. Diesem Vorteil an Flexibilität steht jedoch ein gravierender Nachteil gegenüber. Durch das individuelle Anpassen der Software kann diese nicht mehr ohne Weiteres auf neue Versionen aktualisiert werden.
Umgang mit Heterogenität – Das Konzept der A-/B-Kurse
Authors: Shayanfar Nikta , Weigand Hans-Georg
Published: August 2020

Durch die zahlreichen Wege zur Erlangung einer Hochschulzugangsberechtigung hat die Heterogenität bei Studienanfänger*innen an den Hochschulen zugenommen (z. B. Biehler et al. 2010 oder Leuders et al. 2017). Neben der grundlegenden Aufarbeitung der Schulmathematik und der spezifischen Vorbereitung der Schulabgänger*innen auf die Studieneingangsphase stellt der Umgang mit der Heterogenität eine zusätzliche Herausforderung bei der Durchführung eines Brückenkurses wie etwa demjenigen von optes dar.
Adaptives Üben, adaptive Aufgabentrainings, Modelle grundlegenden Wissens und Könnens
Authors: Götz Gerhard , Hamich Myriam , Pinkernell Guido , Schönwälder David , Ullrich Daniel , Wankerl Sebastian
Published: August 2020

Das Üben hat in der grundlegenden Konzeption der optes-Kurse einen hohen Stellenwert. Die angehenden Studierenden müssen nicht nur über mathematische Kenntnisse, Fähigkeiten und Fertigkeiten verfügen, sondern diese auch zielgerichtet anwenden können. Für die Konzeption ist auch relevant, dass viele der behandelten mathematischen Themengebiete bereits aus der Schule bekannt sind.
A new mechanical calibration strategy for U-channel extrusions
Authors: Raknes Christian Arne , Ma Jun , Welo Torgeir , Paulsen Frode
Published: August 2020

The extrusion process of aluminum profiles introduces dimensional variations commonly exceeding the dimensional tolerance requirements for fit-up and assembly when using automated welding processes in the automotive industry. Improving dimensional accuracy of extrusions is challenging from both a technical and economical point of view. However, an alternative technical approach is to introduce fast and simple downstream processes, such as mechanical calibration, to achieve components or products with improved dimensional characteristics. In this paper, a new mechanical calibration strategy is proposed based on the principle of combining transversal stretching and local bending. The strategy is tested on a U-channel extrusion—which is a particularly challenging geometry for extrusions concerning dimensional accuracy. The overall objective is to improve gap opening variations on U-channels compared with as-extruded dimensional capabilities, especially in the case of alloys that are water quenched to obtain high strength and ductility. The study is also intended to serve as basis for future optimization of the mechanical calibration process. An experimental platform and die/tool system was developed, and finite element simulation was used as a research tool to re-produce and better understand the calibration process, thus further analyzing the mechanisms and deformation characteristics important to dimensional accuracy. The experimental results show that the mechanical calibration strategy has good potential to improve the dimensional accuracy of gap openings of U-channels by 90%. The study demonstrates that as-extruded profiles with tolerance limits exceeding the requirements of the final component can effectively be calibrated with the proposed method and hence used in high-volume manufacturing.
The impact of sacrospinous ligament fixation on pre-existing nocturia and co-existing pelvic floor dysfunction symptoms
Authors: Himmler Maren , Rakhimbayeva Aidana , Sutherland Suzette E. , Roovers Jan-Paul , Yassouridis Alexander , Liedl Bernhard
Published: August 2020

Introduction and hypothesis

To evaluate whether nocturia and coexisting pelvic floor symptoms in women with pelvic organ prolapse (POP) can be improved by ligamentous fixation of apical vaginal prolapse to the sacrospinous ligament.

Methods

We evaluated the PROPEL study data from 281 women with pelvic organ prolapse stage > 2. Bothersome nocturia and coexisting pelvic floor symptoms were assessed with the Pelvic Floor Disorder Inventory (PFDI) questionnaire preoperatively and at 6, 12 and 24 months after successful vaginal prolapse repair. Women with successful reconstruction (POP-Q stage < 1 at all compartments throughout the 2-year follow-up), defined as anatomical “responders,” were compared to the anatomical “non-responders.”

Results

Among the patients completing all PFDI questions (N = 277), anatomical responders and non-responders were the groups of interest for our analysis. We found the occurrence rates of “moderate” or “quite a bit” of nocturia was significantly reduced after surgery in all subgroups (48.7% at baseline vs. 19.5% after 24 months). The occurrence of nocturia was halved for responders compared to non-responders (45.4% and 48.3% at baseline vs. 14% and 29.5% after 24 months). Anatomical non-responders still had a relevant improvement of POP-Q stages, especially in the apical compartment. Prevalence rates of co-existing over- and underactive bladder, fecal incontinence, defecation disorders and pain symptoms were also significantly reduced postoperatively.

Conclusion

Nocturia can be associated with symptomatic POP, with improvements seen following vaginal ligamentous prolapse repair. We caution providers, however, when advising patients of the possible resolution of nocturia following POP reconstruction, that all other traditional etiologies of nocturia must first be ruled out.
Biodiversity of yeasts isolated during spontaneous fermentation of cool climate grape musts
Authors: Cioch-Skoneczny Monika , Satora Paweł , Skoneczny Szymon , Skotniczny Magdalena
Published: August 2020

Biodiversity of native yeasts, especially in winemaking, has hidden potential. In order to use the value of non-Saccharomycesstrains in wine production and to minimise the possibility of its deterioration, it is necessary to thoroughly study the yeast cultures present on grape fruits and in grape must, as well as their metabolic properties. The aim of the study was to characterise the yeast microbiota found during spontaneous fermentation of grape musts obtained from grape varieties ‘Rondo’, ‘Regent’ and ‘Johanniter’. Grapes from two vineyards (Srebrna Góra and Zadora) located in southern Poland were used for the research. Succession of subsequent groups of yeasts was observed during the process.Metschnikowia pulcherrimayeasts were identified both at the beginning and the end of the process.Hanseniaspora uvarum, Wickerhamomyces onychisandTorulaspora delbrueckiistrains were also identified during the fermentation.Torulaspora delbrueckiiandWickerhamomyces onychisstrains were identified only in grape musts obtained from grapes of the Zadora vineyard. These strains may be characteristic of this vineyard and shape the identity of wines formed in it. Our research has provided specific knowledge on the biodiversity of yeast cultures on grapes and during their spontaneous fermentation. The research results presented indicate the possibility of using native strains for fermentation of grape musts, allowing to obtain a product with favourable chemical composition and sensory profile.
Meta-analysis of cognitive functioning in patients with psychotic disorders and obsessive–compulsive symptoms
Authors: Dijkstra Lotte , Vermeulen Jentien , de Haan Lieuwe , Schirmbeck Frederike
Published: August 2020

Obsessive–compulsive symptoms (OCS) in psychotic disorders are associated with unfavorable outcomes, whether this extends to cognitive function remains unclear. We conducted meta-analyses on several cognitive domains to investigate overall group differences between patients with a psychotic disorder and co-occurring OCS (OCS +) and those without OCS (OCS−). We used meta-regression to assess possible confounding effects. No overall associations between OCS + and OCS− in any of the 17 investigated cognitive domains were found. We predominantly found large heterogeneity in effect size and direction among studies. Post-hoc analyses of processing speed tasks not purely based on reaction-time showed worse performance in the OCS + group with a small effect size (SMD = − 0.190; p = 0.029). Meta-regression revealed advanced age was significantly correlated with worse performance of the OCS + group in processing speed (R2 = 0.7), working memory (R2 = 0.11), cognitive inhibition (R2 = 0.59), and cognitive flexibility (R2 = 0.34). Patients fulfilling the criteria for an obsessive–compulsive disorder showed less impairment in cognitive inhibition compared to the OCS + group (R2 = 0.63). Overall, comorbid OCS were not associated with cognitive impairment. However, large heterogeneity between studies highlights the complex nature of factors influencing cognition in people with psychotic disorder and comorbid OCS and warrants further research into possible moderating factors.
Who killed my dog? Use of forensic genetics to investigate an enigmatic case
Authors: Roccaro Mariana , Bini Carla , Fais Paolo , Merialdi Giuseppe , Pelotti Susi , Peli Angelo
Published: August 2020

Genetic testing of animal biological material has become a valuable tool in forensic investigations, and it is successfully used to identify unknown crime perpetrators, to unmask food frauds, or to clarify cases of animal attacks on humans or other animals. When DNA profiling is not possible due to inadequate amounts of nuclear DNA, mitochondrial DNA (mtDNA) testing is the only viable alternative, as in the case of shed hair samples. In this case, a dog was allegedly killed by wild animals while being hosted in a boarding house. Extraneous hair fragments recovered from the dog’s mouth and paws were subjected to genetic analysis: the cytochrome b gene located on mtDNA was amplified and sequenced in order to determine the species responsible for the killing. The mtDNA analysis provided evidence that the dog was killed by other dogs, thus unmasking a false wild animal attack and putting the case in an entirely different perspective.
Computation and efficiency of potential function minimizers of combinatorial congestion games
Authors: Kleer Pieter , Schäfer Guido
Published: August 2020

We study the computation and efficiency of pure Nash equilibria in combinatorial congestion games, where the strategies of each player i are given by the binary vectors of a polytope $$P_i$$

P
i

. Our main goal is to understand which structural properties of such polytopal congestion games enable us to derive an efficient equilibrium selection procedure to compute pure Nash equilibria with attractive social cost approximation guarantees. To this aim, we identify two general properties of the underlying aggregation polytope$$P_N = \sum _i P_i$$

P
N

=

∑
i

P
i

which are sufficient for our results to go through, namely the integer decomposition property (IDP) and the box-totally dual integrality property (box-TDI). Our main results for polytopal congestion games satisfying IDP and box-TDI are as follows: (i) we show that pure Nash equilibria can be computed in polynomial time. In fact, we obtain this result through a general framework for separable convex function minimization, which might be of independent interest. (ii) We bound the inefficiency of these equilibria and show that this provides a tight bound on the price of stability. (iii) We also prove that these results extend to strong equilibria for the “bottleneck variant” of polytopal congestion games. Examples of polytopal congestion games satisfying IDP and box-TDI include common source network congestion games, symmetric totally unimodular congestion games, non-symmetric matroid congestion games and symmetric matroid intersection congestion games (in particular, r-arborescences and strongly base-orderable matroids).
Engineering the cellulolytic extreme thermophile Caldicellulosiruptor bescii to reduce carboxylic acids to alcohols using plant biomass as the energy source
Authors: Rubinstein Gabriel M , Lipscomb Gina L , Williams-Rhaesa Amanda M , Schut Gerrit J , Kelly Robert M , Adams Michael W W
Published: August 2020

Caldicellulosiruptor bescii is the most thermophilic cellulolytic organism yet identified (Topt 78 °C). It grows on untreated plant biomass and has an established genetic system thereby making it a promising microbial platform for lignocellulose conversion to bio-products. Here, we investigated the ability of engineered C. bescii to generate alcohols from carboxylic acids. Expression of aldehyde ferredoxin oxidoreductase (aor from Pyrococcus furiosus) and alcohol dehydrogenase (adhA from Thermoanaerobacter sp. X514) enabled C. bescii to generate ethanol from crystalline cellulose and from biomass by reducing the acetate produced by fermentation. Deletion of lactate dehydrogenase in a strain expressing the AOR–Adh pathway increased ethanol production. Engineered strains also converted exogenously supplied organic acids (isobutyrate and n-caproate) to the corresponding alcohol (isobutanol and hexanol) using both crystalline cellulose and switchgrass as sources of reductant for alcohol production. This is the first instance of an acid to alcohol conversion pathway in a cellulolytic microbe.
Molecular mediators of peritoneal metastasis in pancreatic cancer
Authors: Avula Leela Rani , Hagerty Brendan , Alewine Christine
Published: August 2020

Pancreatic cancer is the third leading cause of cancer death in the USA, and pancreatic ductal adenocarcinoma (PDA) constitutes 85% of pancreatic cancer diagnoses. PDA frequently metastasizes to the peritoneum, but effective treatment of peritoneal metastasis remains a clinical challenge. Despite this unmet need, understanding of the biological mechanisms that contribute to development and progression of PDA peritoneal metastasis is sparse. By contrast, a vast number of studies have investigated mechanisms of peritoneal metastasis in ovarian and gastric cancers. Here, we contrast similarities and differences between peritoneal metastasis in PDA as compared with those in gastric and ovarian cancer by outlining molecular mediators involved in each step of the peritoneal metastasis cascade. This review aims to provide mechanistic insights that could be translated into effective targeted therapies for patients with peritoneal metastasis from PDA.
Drug efficacy and toxicity prediction: an innovative application of transcriptomic data
Authors: Xia Xuhua
Published: August 2020

Drug toxicity and efficacy are difficult to predict partly because they are both poorly defined, which I aim to remedy here from a transcriptomic perspective. There are two major categories of drugs: (1) restorative drugs aiming to restore an abnormal cell, tissue, or organ to normal function (e.g., restoring normal membrane function of epithelial cells in cystic fibrosis), and (2) disruptive drugs aiming to kill pathogens or malignant cells. These two types of drugs require different definition of efficacy and toxicity. I outlined rationales for defining transcriptomic efficacy and toxicity and illustrated numerically their application with two sets of transcriptomic data, one for restorative drugs (treating cystic fibrosis with lumacaftor/ivacaftor aiming to restore the cellular function of epithelial cells) and the other for disruptive drugs (treating acute myeloid leukemia with prexasertib). The conceptual framework presented will help and sensitize researchers to collect data required for determining drug toxicity.
Interaction-based creation and maintenance of continuously usable trace links between requirements and source code
Authors: Hübner Paul , Paech Barbara
Published: August 2020

Trace links between requirements and code are beneficial for many software engineering tasks such as maintenance, program comprehension, and re-engineering. If trace links are created and used continuously during a project, they need to have high precision and recall to be useful. However, manual trace link creation is cumbersome and existing automatic trace link creation methods are typically only applied retrospectively and to structured requirements. Therefore, they focus on recall and accept manual effort to cope with low precision. Such manual effort is not acceptable continuously. Furthermore, the maintenance of existing links along with changing artefacts in a project is neglected in most automatic trace link creation approaches. Therefore, we developed and evaluated an interaction log-based trace link creation approachILto continuously provide correct trace links during a project.ILlinks unstructured requirements specified in an issue tracker and source code managed in a version control system. In the latest version,ILCom, our approach uses the interactions of developers with files in an integrated development environment and issue identifiers provided in commit messages to create trace links continuously after each commit. In this paper, we presentILCom, its most recent evaluation study, and a systematic literature review (SLR) about trace link maintenance (TM). We also present a TM process forILCombased on two approaches from our SLR. In the evaluation study, we show that precision ofILComcreated links is above 90% and recall almost at 80%. In the SLR, we discuss 16 approaches. Our approach is the first trace link creation approach with very good precision and recall and integrated trace maintenance.
Grazing resistance in phytoplankton
Authors: Lürling Miquel
Published: August 2020

Phytoplankton is confronted with a variable assemblage of zooplankton grazers that create a strong selection pressure for traits that reduce mortality. Phytoplankton is, however, also challenged to remain suspended and to acquire sufficient resources for growth. Consequently, phytoplanktic organisms have evolved a variety of strategies to survive in a variable environment. An overview is presented of the various phytoplankton defense strategies, and costs and benefits of phytoplankton defenses with a zooming in on grazer-induced colony formation. The trade-off between phytoplankton competitive abilities and defenses against grazing favor adaptive trait changes—rapid evolution and phenotypic plasticity—that have the potential to influence population and community dynamics, as exemplified by controlled chemostat experiments. An interspecific defense–growth trade-off could explain seasonal shifts in the species composition of an in situ phytoplankton community yielding defense and growth rate as key traits of the phytoplankton. The importance of grazing and protection against grazing in shaping the phytoplankton community structure should not be underestimated. The trade-offs between nutrient acquisition, remaining suspended, and grazing resistance generate the dynamic phytoplankton community composition.
The ability to get everywhere: dispersal modes of free-living, aquatic nematodes
Authors: Ptatscheck Christoph , Traunspurger Walter
Published: August 2020

Nematodes colonize almost all aquatic habitats worldwide. Despite their small size, restricted locomotion and lack of pelagic larvae, they can reach even isolated habitats within a short time. In this review, we examine the underlying dispersal modes, considering their active movement in substrates and water, their drift by water and wind, rafting, zoochory as well as human-mediated vectors. These modes are limited by morphology and habitat structure, ecological factors and especially by hydrodynamics. Active dispersal is effective over short distances, but with increasing water-flow velocity, passive dispersal modes, which enable long-range transfer, become important. In fact, the transport of nematodes over thousands of kilometers via ship water tanks and by hitchhiking on sea turtles has been documented. Overland dispersal vectors include wind and birds whereas rafting enables an aggregated distribution because food is available, and reproduction is possible onboard the rafts. The diversity of possible dispersal modes is high and offers a reasonably chance for gravid females or groups of nematodes to be transferred even to remote environments. Their immigration is continuous, and supported by their rapid, parthenogenetic reproduction, nematodes are effective pioneers with the ability to (re)colonize new or disturbed habitats or rebalance already existing communities.
Expected effects of the US tax reform on other countries: global and local survey evidence
Authors: Boumans Dorine , Fuest Clemens , Krolage Carla , Wohlrabe Klaus
Published: August 2020

The Tax Cuts and Jobs Act constitutes the largest change to the US tax system since the 1980s and thoroughly alters the way in which multinational companies are taxed. Current assessments on the reform’s international impact vary widely. This article sheds light on the tax reform’s expected effects on other countries. We first use representative German business survey data to analyze the impact of the reform on German firms. Many firms with substantial US revenues or capacities in the USA intend to expand US investment in response to the reform, in particular large firms and manufacturing companies. The effects on investment in Germany are ambiguous: While some firms substitute between investment locations, others expand in both countries. We subsequently extend our analysis to a global level using worldwide survey data. The results suggest a negative impact on tax revenues and investment in countries with close economic ties to the USA.
Mechanical properties of all-cellulose composites from end-of-life textiles
Authors: Baghaei Behnaz , Compiet Sam , Skrifvars Mikael
Published: August 2020

This paper reports the recycling of end-of-life cellulose containing textiles by fabrication of all-cellulose composites (ACCs). Discharged denim fabrics were used as the reinforcement while dissolved cellulose from two different cellulose resources was used as the matrix phase. Virgin cotton fibres and recovered cotton from polyester/cotton (polycotton) waste fabrics were used to form the matrix phase. The process comprises preparing a 6 wt% cellulose solution by dissolving cellulose solution in a ionic liquid, 1-butyl-3-methyl imidazolium acetate ([BMIM][Ac]), this solution acted as a precursor for the matrix component. The denim fabrics were first embedded in the cellulose/IL solution followed by removal of the IL by washing to form the composite. The effect of reuse of the recovered IL by distillation was also investigated. The mechanical properties of the obtained ACCs were determined regarding tensile, impact and flexural properties. Fabricated ACC composite laminates were further characterised regarding structure by scanning electron microscopy.
Tropical limit of matrix solitons and entwining Yang–Baxter maps
Authors: Dimakis Aristophanes , Müller-Hoissen Folkert
Published: August 2020

We consider a matrix refactorization problem, i.e., a “Lax representation,” for the Yang–Baxter map that originated as the map of polarizations from the “pure” 2-soliton solution of a matrix KP equation. Using the Lax matrix and its inverse, a related refactorization problem determines another map, which is not a solution of the Yang–Baxter equation, but satisfies a mixed version of the Yang–Baxter equation together with the Yang–Baxter map. Such maps have been called “entwining Yang–Baxter maps” in recent work. In fact, the map of polarizations obtained from a pure 2-soliton solution of a matrix KP equation, and already for the matrix KdV reduction, is not in general a Yang–Baxter map, but it is described by one of the two maps or their inverses. We clarify why the weaker version of the Yang–Baxter equation holds, by exploring the pure 3-soliton solution in the “tropical limit,” where the 3-soliton interaction decomposes into 2-soliton interactions. Here, this is elaborated for pure soliton solutions, generated via a binary Darboux transformation, of matrix generalizations of the two-dimensional Toda lattice equation, where we meet the same entwining Yang–Baxter maps as in the KP case, indicating a kind of universality.
Existence of n-cycles and border-collision bifurcations in piecewise-linear continuous maps with applications to recurrent neural networks
Authors: Monfared Z. , Durstewitz D.
Published: August 2020

Piecewise linear recurrent neural networks (PLRNNs) form the basis of many successful machine learning applications for time series prediction and dynamical systems identification, but rigorous mathematical analysis of their dynamics and properties is lagging behind. Here, we contribute to this topic by investigating the existence ofn-cycles$$(n\ge 3)$$(n≥3)and border-collision bifurcations in a class ofm-dimensional piecewise linear continuous maps which have the general form of a PLRNN. This is particularly important as for one-dimensional maps the existence of 3-cycles implies chaos. It is shown that thesen-cycles collide with the switching boundary in a border-collision bifurcation, and parametric regions for the existence of both stable and unstablen-cycles and border-collision bifurcations will be derived theoretically. We then discuss how our results can be extended and applied to PLRNNs. Finally, numerical simulations demonstrate the implementation of our results and are found to be in good agreement with the theoretical derivations. Our findings thus provide a basis for understanding periodic behavior in PLRNNs, how it emerges in bifurcations, and how it may lead into chaos.
The Lorenz system: hidden boundary of practical stability and the Lyapunov dimension
Authors: Kuznetsov N. V. , Mokaev T. N. , Kuznetsova O. A. , Kudryashova E. V.
Published: August 2020

On the example of the famous Lorenz system, the difficulties and opportunities of reliable numerical analysis of chaotic dynamical systems are discussed in this article. For the Lorenz system, the boundaries of global stability are estimated and the difficulties of numerically studying the birth of self-excited and hidden attractors, caused by the loss of global stability, are discussed. The problem of reliable numerical computation of the finite-time Lyapunov dimension along the trajectories over large time intervals is discussed. Estimating the Lyapunov dimension of attractors via the Pyragas time-delayed feedback control technique and the Leonov method is demonstrated. Taking into account the problems of reliable numerical experiments in the context of the shadowing and hyperbolicity theories, experiments are carried out on small time intervals and for trajectories on a grid of initial points in the attractor’s basin of attraction.
Peronospora aquilegiicola made its way to Germany: the start of a new pandemic?
Authors: Thines Marco , Buaya Anthony , Ali Tahir , Brand Thomas
Published: August 2020

Peronospora aquilegiicola is a destructive pathogen of columbines and has wiped out most Aquilegia cultivars in several private and public gardens throughout Britain. The pathogen, which is native to East Asia was noticed in England and Wales in 2013 and quickly spread through the country, probably by infested plants or seeds. To our knowledge, the pathogen has so far not been reported from other parts of Europe. Here, we report the emergence of the pathogen in the northwest of Germany, based on morphological and phylogenetic evidence. As the pathogen was found in a garden in which no new columbines had been planted recently, we assume that the pathogen has already spread from its original point of introduction in Germany. This calls for an increased attention to the further spread of the pathogen and the eradication of infection spots to avoid the spread to naturally occurring columbines in Germany and to prevent another downy mildew from becoming a global threat, like Peronospora belbahrii and Plasmopara destructor, the downy mildews of basil and balsamines, respectively.
Dependence of skill and spread of the ensemble forecasts on the type of perturbation and its relationship with long-term norms of precipitation and temperature
Authors: Duniec Grzegorz , Mazur Andrzej
Published: August 2020

A new computing cluster has been operating since 2016 at the Institute of Meteorology and Water Management – National Research Institute. Increasing computing power enabled the implementation of ensemble prediction system forecasts in the operational mode and the use of a new computer for research purposes. As part of the priority project on “Study of Disturbances in the Representation of Modeling Uncertainty in Ensemble Development” and the earlier project entitled “COSMO Towards Ensemble in Km in Our Countries), implemented in the Working Group 7 (Predictability and Ensemble Methods) as part of the COSMO modeling consortium, specific studies were carried out to test ensemble forecasts. This research concerned the impact of variability of physical fields characterizing the soil surface (a selected parameter determining evaporation from the soil surface and soil surface temperature) using various methods of perturbation. Numerical experiments were completed for the warm period (from June to September) 2013.
Extraction of Copper from Copper-Bearing Materials by Sulfation Roasting with SO2-O2 Gas
Authors: Wan Xingbang , Shi Junjie , Taskinen Pekka , Jokilaakso Ari
Published: August 2020

Recycling metals from secondary materials and more complex ores has recently been attracting more attention, creating a need for more precise separation methods of different elements. This study proposed a sulfation-roasting method and designed thermodynamic conditions to selectively facilitate the formation of copper sulfate while separating iron as oxide.
The roasting behaviors for chalcopyrite, copper slag, and pure copper compounds were investigated in a 0.5% SO2–0.5% O2–99% Ar atmosphere at 600°C. X-ray fluorescence spectroscopy, x-ray diffractometry, scanning electron microscopy, and energy dispersive x-ray spectrometry were used to characterize the raw materials and roasting products.
The proposed methodology was confirmed for a complete separation of Cu from Fe, and, further, the sulfation-roasting mechanism of chalcopyrite was confirmed by thermodynamic calculations and experimental observations. These will provide a theoretical basis for copper recycling from both complex primary and secondary copper-bearing materials.
Inhibition of Aquaporin 4 Decreases Amyloid Aβ40 Drainage Around Cerebral Vessels
Authors: Rosu Gabriela-Camelia , Catalin Bogdan , Balseanu Tudor Adrian , Laurentiu Mogoanta , Claudiu Margaritescu , Kumar-Singh Samir , Daniel Pirici
Published: August 2020

Aquaporin-4 (AQP4) is located mainly in the astrocytic end-feet around cerebral blood vessels and regulates ion and water homeostasis in the brain. While deletion of AQP4 is shown to reduce amyloid-β (Aβ) clearance and exacerbate Aβ peptide accumulation in plaques and vessels of Alzheimer’s disease mouse models, the mechanism and clearing pathways involved are debated. Here, we investigated how inhibiting the function of AQP4 in healthy male C57BL/6 J mice impacts clearance of Aβ40, the more soluble Aβ isoform. Using two-photon in vivo imaging and visualizing vessels with Sulfurodamine 101 (SR101), we first showed that Aβ40 injected as a ≤ 0.5-μl volume in the cerebral cortex diffused rapidly in parenchyma and accumulated around blood vessels. In animals treated with the AQP4 inhibitor TGN-020, the perivascular Aβ40 accumulation was significantly (P < 0.001) intensified by involving four times more vessels, thus suggesting a generalized clearance defect associated with vessels. Increasing the injecting volume to ≥ 0.5 ≤ 1 μl decreased the difference of Aβ40-positive vessels observed in non-treated and AQP4 inhibitor-treated animals, although the difference was still significant (P = 0.001), suggesting that larger injection volumes could overwhelm intramural vascular clearance mechanisms. While both small and large vessels accumulated Aβ40, for the ≤ 0.5-μl volume group, the average diameter of the Aβ40-positive vessels tended to be larger in control animals compared with TGN-020-treated animals, although the difference was non-significant (P = 0.066). Using histopathology and ultrastructural microscopy, no vascular structural change was observed after a single massive dose of TGN-020. These data suggest that AQP4 deficiency is directly involved in impaired Aβ brain clearance via the peri-/para-vascular routes, and AQP4-mediated vascular clearance might counteract blood-brain barrier abnormalities and age-related vascular amyloidopathy.
Antithrombotic management of patients with atrial fibrillation—Dutch anticoagulant initiatives anno 2020
Authors: Chu G. , Seelig J. , Trinks-Roerdink E. M. , Geersing G. J. , Rutten F. H. , de Groot J. R. , Huisman M. V. , Hemels M. E. W.
Published: August 2020

In recent years, as more and more experience has been gained with prescribing direct oral anticoagulants (DOACs), new research initiatives have emerged in the Netherlands to improve the safety and appropriateness of DOAC treatment for stroke prevention in patients with atrial fibrillation (AF). These initiatives address several contemporary unresolved issues, such as inappropriate dosing, non-adherence and the long-term management of DOAC treatment. Dutch initiatives have also contributed to the development and improvement of risk prediction models. Although fewer bleeding complications (notably intracranial bleeding) are in general seen with DOACs in comparison with vitamin K antagonists, to successfully identify patients with high bleeding risk and to tailor anticoagulant treatment accordingly to mitigate this increased bleeding risk, is one of the research aims of recent and future years. This review highlights contributions from the Netherlands that aim to address these unresolved issues regarding the anticoagulant management in AF in daily practice, and provides a narrative overview of contemporary stroke and bleeding risk assessment strategies.
The role of long-term mechanical circulatory support in patients with advanced heart failure
Authors: Felix S. E. A. , de Jonge N. , Caliskan K. , Birim O. , Damman K. , Kuijpers M. , Tops L. F. , Palmen M. , Ramjankhan F. Z.
Published: August 2020

In patients with end-stage heart failure, advanced therapies such as heart transplantation and long-term mechanical circulatory support (MCS) with a left ventricular assist device (LVAD) have to be considered. LVADs can be implanted as a bridge to transplantation or as an alternative to heart transplantation: destination therapy. In the Netherlands, long-term LVAD therapy is gaining importance as a result of increased prevalence of heart failure together with a low number of heart transplantations due to shortage of donor hearts. As a result, the difference between bridge to transplantation and destination therapy is becoming more artificial since, at present, most patients initially implanted as bridge to transplantation end up receiving extended LVAD therapy. Following LVAD implantation, survival after 1, 2 and 3 years is 83%, 76% and 70%, respectively. Quality of life improves substantially despite important adverse events such as device-related infection, stroke, major bleeding and right heart failure. Early referral of potential candidates for long-term MCS is of utmost importance and positively influences outcome. In this review, an overview of the indications, contraindications, patient selection, clinical outcome and optimal time of referral for long-term MCS is given.