bluuebunny/crossref_metadata_2025 huggingface dataset:
Effective field theory for closed strings near the Hagedorn temperature
Authors: Brustein Ram , Zigdon Yoav
Published: April 2021

Abstract

We discuss interacting, closed, bosonic and superstrings in thermal equilibrium at temperatures close to the Hagedorn temperature in flat space. We calculate S-matrix elements of the strings at the Hagedorn temperature and use them to construct a low-energy effective action for interacting strings near the Hagedorn temperature. We show, in particular, that the four-point amplitude of massless winding modes leads to a positive quartic interaction. Furthermore, the effective field theory has a generalized conformal structure, namely, it is conformally invariant when the temperature is assigned an appropriate scaling dimension. Then, we show that the equations of motion resulting from the effective action possess a winding-mode-condensate background solution above the Hagedorn temperature and present a worldsheet conformal field theory, similar to a Sine-Gordon theory, that corresponds to this solution. We find that the Hagedorn phase transition in our setup is second order, in contrast to a first-order transition that was found previously in different setups.
Precision QCD phenomenology of exotic spin-2 search at the LHC
Authors: Das Goutam , Kumar M. C. , Samanta Kajal
Published: April 2021

Abstract

The complete next-to-next-to leading order (NNLO) QCD correction matched with next-to-next-to leading logarithm (NNLL) has been studied for Drell-Yan production via spin-2 particle at the Large hadron collider (LHC). We consider generic spin-2 particle which couples differently to quarks and gluons (non-universal scenario). The threshold enhanced analytical coefficient has been obtained up to third order using the universal soft function and the process dependent form factors at the same order. We performed a detailed phenomenological analysis and gave a prediction for the 13 TeV LHC for the search of such BSM signature. We found that the resummed result gives sizeable corrections over a wide range of invariant mass of the lepton pair. The scale variation also stabilizes at this order and reduces to 4%. As a by-product, we also provide ingredients for third-order soft-virtual (SV) prediction as well as resummation and study the impact on LHC searches.
Wie wirken Generikaquoten? Eine Analyse am Beispiel der HIV-Infektion
Authors: Rüsenberg Robin , Baumgarten Axel , Mauss Stefan , Gradl Gabriele , Schulz Martin , Bartmeyer Barbara , Kollan Christian , Schmidt Daniel
Published: April 2021

Hintergrund

Die Steuerungsinstrumente der Arzneimittelversorgung in der gesetzlichen Krankenversicherung (GKV) sind schon länger Bestandteil der gesundheitspolitischen Reformdebatte. Über die Jahre hat sich eine Gemengelage sehr verschiedener Werkzeuge herausgebildet, die zumeist auf eine Kontrolle der Arzneimittelausgaben zielen. Die Instrumente der regionalen Verordnungssteuerung fokussieren vor allem auf eine Verhaltenssteuerung des verordnenden Arztes. Zu erwähnen ist nicht zuletzt der verstärkte Einsatz von indikationsbezogenen Quoten, vorrangig Leitsubstanzen und/oder Generika/Biosimilars. Diese gibt es mittlerweile auch im Bereich des Humanen Immundefizienz-Virus (HIV), etwa die seit 2020 in Bayern und Berlin eingeführten Generikaquoten für HIV-Therapeutika.

Zielstellung

Ziel des vorliegenden Beitrages ist es, auf Grundlage von GKV-Apothekenabrechnungsdaten das Potenzial sowie Grenzen von Generikaquotenlösungen in der HIV-Versorgung zu analysieren und Handlungsempfehlungen zu skizzieren.

Ergebnisse

Es zeigte sich, dass das Quotenpotenzial für Generika im patentfreien Bereich in der HIV-Versorgung bereits weitgehend ausgeschöpft wird. Dieser Umstand ist vor allem darauf zurückzuführen, dass die HIV-Verordner den Austausch durch Verzicht auf Aut-idem-Kreuze auf dem Kassenrezept unterstützen.

Diskussion

Das steuerungspolitische Optimum ist fast erreicht. Dies ist auf das geeignete Instrumentarium zurückzuführen, das aus dem Rahmenvertrag zur Arzneimittelversorgung und einer leitliniengerechten Wirkstoffverordnung durch den Arzt besteht – in Verbindung mit dem AMNOG(Arzneimittelmarktneuordnungsgesetz)-Verfahren und Festbeträgen. Leitlinienkonformität und (existierende) Eintablettenregime müssen beibehalten werden, damit die gute Versorgungsqualität gewährleistet bleibt.
Die Nutzbarmachung von Daten für Public Health und Gesundheitsversorgung – ein gemeinsames Ziel der EU-Mitgliedsstaaten
Authors: Meyer Ingo
Published: April 2021

Die Gesundheit der Bevölkerung – im Sinne von Prävention und Versorgung – braucht gute Daten. Daten unterstützen die Entscheidungsfindung auf der Systemebene ebenso wie konkrete Maßnahmen auf der Individualebene. Daten sind außerdem Voraussetzung für Forschung und die Entwicklung von Innovation. Gleichzeitig sind Daten Mangelware: Sie liegen nur in Ausschnitten oder für ganze Systemteile überhaupt nicht vor, sie decken Sachverhalte nur approximativ ab oder sind in Formaten gebunden, die eine automatisierte (bzw. skalierbare) Verarbeitung erschweren bis unmöglich machen. Zudem sind gerade Gesundheitsdaten höchst sensibel und entsprechend geschützt, was ihre Verwertung noch herausfordernder macht.

Mit diesen Herausforderungen steht Deutschland nicht allein da, sie finden sich in ähnlicher Form in allen anderen Mitgliedsstaaten der Europäischen Union (EU). Das Potenzial einer gemeinsamen Problemdefinition sowie der gemeinsamen Entwicklung von Lösungen wird in Deutschland bisher aber nur wenig genutzt. Der Artikel gibt einen Einblick in verschiedene EU-Initiativen rund um das Thema Gesundheitsdaten. Im Vordergrund steht dabei die Frage, wie deutsche Akteur:innen Zugang zu diesen Initiativen bekommen können, um so einerseits vom Wissen und den Erfahrungen in den Nachbarländern zu profitieren, aber auch um eigenes Wissen in diesen Kreis zurückgeben zu können.
Tröpfchenexposition bei Tracheotomie
Authors: Plettenberg C. , Geipel K. , Stenin I. , Klenzner T. , Wagenmann M. , Schipper J. , Scheckenbach K.
Published: April 2021

Hintergrund

Die Pandemie COVID-19 („coronavirus disease 2019“) zeichnet sich durch eine hohe Infektiosität bei Tröpfchenübertragung und hoher Virusdichte in den oberen Atemwegen aus. Schwere Krankheitsverläufe stehen mit interstitiellen, beatmungspflichtigen Pneumonien in Verbindung, bei denen regelmäßig Tracheotomien (TT), ein tröpfchen- und aerosolerzeugender medizinischer Eingriff, notwendig werden. Die TT als potenzielles Infektionsrisiko für medizinisches Personal wird in der Literatur kaum behandelt. Deshalb war es Ziel dieser Studie, die Tröpfchenexposition des Op.-Teams während der Tracheotomie zu quantifizieren, um hierdurch die Anforderungen an die notwendige persönliche Schutzausrüstung (PSA) besser zu definieren.

Material und Methoden

Bei 4 nichtinfektiösen Patienten wurde eine chirurgische Tracheotomie durchgeführt, bei der der Chirurg und seine Assistenz jeweils eine chirurgische Mund-Nasen-Maske mit Klarsichtvisier trugen. Nach Durchführung des Eingriffs bestimmten wir Tröpfchenart, -verteilung und -menge auf dem Visier makroskopisch und mikroskopisch.

Ergebnisse

Auf den Visieren fanden sich durchschnittlich 29 Tröpfchen im mittleren Drittel des Visiers, 4 im rechten Drittel und 13 im linken Drittel, bei einer durchschnittlichen Tröpfchengröße von 571 µm (± 381 µm). Die kleinsten Tröpfchen waren 55 µm, die größten 1431 µm groß. Eine Zunahme der Tröpfchen fanden sich bei vermehrter Ventilation während des Eingriffs. Bluttröpfchen waren häufiger als Sekrettröpfchen.

Schlussfolgerung

Es konnte eine deutliche Kontamination des Gesichtsvisiers mit Tröpfchen dargestellt werden. Gerade im Fall einer TT von hochinfektiösen Patienten, z. B. COVID-19, ist demnach die Verwendung einer Kapuzen-Kopfbedeckung in Kombination mit einem Atemschutzgerät mit Luftreinigung mit Stromversorgung empfehlenswert, um einen Infektionsschutz des Operateurs und der Op.-Assistenz bestmöglich zu gewährleisten.
Diversity and functional structure of soil animal communities suggest soil animal food webs to be buffered against changes in forest land use
Authors: Pollierer Melanie M. , Klarner Bernhard , Ott David , Digel Christoph , Ehnes Roswitha B. , Eitzinger Bernhard , Erdmann Georgia , Brose Ulrich , Maraun Mark , Scheu Stefan
Published: April 2021

Forest soil and litter is inhabited by a diverse community of animals, which directly and indirectly rely on dead organic matter as habitat and food resource. However, community composition may be driven by biotic or abiotic forces, and these vary with changes in habitat structure and resource supply associated with forest land use. To evaluate these changes, we compiled comprehensive data on the species composition of soil animal communities and environmental factors in forest types varying in land-use intensity in each of three regions in Germany, i.e., coniferous, young managed, old managed, and unmanaged beech forests. Coniferous forests featured high amounts of leaf litter and low microbial biomass concentrations contrasting in particular unmanaged beech forests. However, soil animal diversity and functional community composition differed little between forest types, indicating resilience against disturbance and forest land use. Structural equation modelling suggested that despite a significant influence of forest management on resource abundance and quality, the biomass of most soil fauna functional groups was not directly affected by forest management or resource abundance/quality, potentially because microorganisms hamper the propagation of nutrients to higher trophic levels. Instead, detritivore biomass depended heavily on soil pH. Macrofauna decomposers thrived at high pH, whereas mesofauna decomposers benefitted from low soil pH, but also from low biomass of macrofauna decomposers, potentially due to habitat modification by macrofauna decomposers. The strong influence of soil pH shows that decomposer communities are structured predominantly by regional abiotic factors exceeding the role of local biotic factors such as forest type.
Factors associated with SARS-CoV-2 infection and outcome in patients with solid tumors or hematological malignancies: a single-center study
Authors: Goudsmit Anouk , Cubilier Edouard , Meert Anne-Pascale , Aftimos Philippe , Stathopoulos Konstantinos , Spilleboudt Chloe , Loizidou Angela
Published: April 2021

Background

Immunocompromised cancer patients are presumed to be at high risk of developing COVID-19 infection. Predisposing factors to contracting COVID-19 and to severe outcomes have been described in registries but were not compared between solid tumors and hematological malignancies.

Method

This retrospective single oncologic center study included adults with solid tumors or hematological malignancies referred to testing by naso-pharyngeal swab for a SARS-CoV-2 RT-PCR from March 10 to May 18, 2020.

Results

A total of 212 patients were included in the study. Forty-five (21%) were tested positive with SARS-CoV-2. The univariate analysis with positive SARS-CoV-2 PCR as a dependent variable reveals significant odds ratios (ORs) for age—with a mean of 62.5 years—(OR: 1.05, 95% CI: 1.02–1.08), performance status ≥2 (OR: 2.38, 95% CI: 1.22–4.70), inpatient status (OR: 2.36, 95%CI: 1.11–4.91), and hematological malignancies (OR: 2.48, 95% CI: 1.23–4.96). In contrast, OR for solid tumors reveals a negative association (OR: 0.40, 95% CI: 0.20–0.81). When integrating severe outcome (ICU admission or COVID-19-related death) as a dependent variable, the univariate logistic regression model shows significant ORs for pre-existing lymphopenia (OR: 4.0, 95% CI: 1.17–15.04), hematological malignancies (OR: 3.73, 95% CI: 1.09–13.80), and a negative association for solid tumors (OR: 0.27; 95% CI: 0.07–0.92).

Conclusion

In patients referred for SARS-CoV-2 testing, hematological malignancies were associated with a higher risk of COVID-19 infection and severe outcomes. Other factors were age and inpatient status.
Compliance of the cerebrospinal space: comparison of three methods
Authors: Kazimierska Agnieszka , Kasprowicz Magdalena , Czosnyka Marek , Placek Michał M. , Baledent Olivier , Smielewski Peter , Czosnyka Zofia
Published: April 2021

Background

Cerebrospinal compliance describes the ability of the cerebrospinal space to buffer changes in volume. Diminished compliance is associated with increased risk of potentially threatening increases in intracranial pressure (ICP) when changes in cerebrospinal volume occur. However, despite various methods of estimation proposed so far, compliance is seldom used in clinical practice. This study aimed to compare three measures of cerebrospinal compliance.

Methods

ICP recordings from 36 normal-pressure hydrocephalus patients who underwent infusion tests with parallel recording of transcranial Doppler blood flow velocity were retrospectively analysed. Three methods were used to calculate compliance estimates during changes in the mean ICP induced by infusion of fluid into the cerebrospinal fluid space: (a) based on Marmarou’s model of cerebrospinal fluid dynamics (CCSF), (b) based on the evaluation of changes in cerebral arterial blood volume (CCaBV), and (c) based on the amplitudes of peaks P1 and P2 of ICP pulse waveform (CP1/P2).

Results

Increase in ICP caused a significant decrease in all compliance estimates (p < 0.0001). Time courses of compliance estimators were strongly positively correlated with each other (group-averaged Spearman correlation coefficients: 0.94 [0.88–0.97] for CCSF vs. CCaBV, 0.77 [0.63–0.91] for CCSF vs. CP1/P2, and 0.68 [0.48–0.91] for CCaBV vs. CP1/P2).

Conclusions

Indirect methods, CCaBV and CP1/P2, allow for the assessment of relative changes in cerebrospinal compliance and produce results exhibiting good correlation with the direct method of volumetric manipulation. This opens the possibility of monitoring relative changes in compliance continuously.
Characteristics, potentials, and limitations of open-source Simulink projects for empirical research
Authors: Boll Alexander , Brokhausen Florian , Amorim Tiago , Kehrer Timo , Vogelsang Andreas
Published: April 2021

Simulink is an example of a successful application of the paradigm of model-based development into industrial practice. Numerous companies create and maintain Simulink projects for modeling software-intensive embedded systems, aiming at early validation and automated code generation. However, Simulink projects are not as easily available as code-based ones, which profit from large publicly accessible open-source repositories, thus curbing empirical research. In this paper, we investigate a set of 1734 freely available Simulink models from 194 projects and analyze their suitability for empirical research. We analyze the projects considering (1) their development context, (2) their complexity in terms of size and organization within projects, and (3) their evolution over time. Our results show that there are both limitations and potentials for empirical research. On the one hand, some application domains dominate the development context, and there is a large number of models that can be considered toy examples of limited practical relevance. These often stem from an academic context, consist of only a few Simulink blocks, and are no longer (or have never been) under active development or maintenance. On the other hand, we found that a subset of the analyzed models is of considerable size and complexity. There are models comprising several thousands of blocks, some of them highly modularized by hierarchically organized Simulink subsystems. Likewise, some of the models expose an active maintenance span of several years, which indicates that they are used as primary development artifacts throughout a project’s lifecycle. According to a discussion of our results with a domain expert, many models can be considered mature enough for quality analysis purposes, and they expose characteristics that can be considered representative for industry-scale models. Thus, we are confident that a subset of the models is suitable for empirical research. More generally, using a publicly available model corpus or a dedicated subset enables researchers to replicate findings, publish subsequent studies, and use them for validation purposes. We publish our dataset for the sake of replicating our results and fostering future empirical research.
Joint Family and Work Trajectories and Multidimensional Wellbeing
Authors: Comolli C. L. , Bernardi L. , Voorpostel M.
Published: April 2021

Informed by the life course perspective, this paper investigates whether and how employment and family trajectories are jointly associated with subjective, relational and financial wellbeing later in life. We draw on data from the Swiss Household Panel which combines biographical retrospective information on work, partnership and childbearing trajectories with 19 annual waves containing a number of wellbeing indicators as well as detailed socio-demographic and social origin information. We use sequence analysis to identify the main family and work trajectories for men and women aged 20–50 years old. We use OLS regression models to assess the association between those trajectories and their interdependency with wellbeing. Results reveal a joint association between work and family trajectories and wellbeing at older age, even net of social origin and pre-trajectory resources. For women, but not for men, the association is also not fully explained by proximate (current family and work status) determinants of wellbeing. Women’s stable full-time employment combined with traditional family trajectories yields a subjective wellbeing premium, whereas childlessness and absence of a stable partnership over the life course is associated with lower levels of financial and subjective wellbeing after 50 especially in combination with a trajectory of weak labour market involvement. Relational wellbeing is not associated with employment trajectories, and only weakly linked to family trajectories among men.
The Association between Home Environment and Quality of Life in Children and Adolescents in Hangzhou City, China
Authors: Huang Xianhong , Hua Le , Zhou Xueyang , Zhang Hao , Zhang Meng , Wang Sheng , Qin Shangren , Chen Jie , Wang XiaoHe
Published: April 2021

To investigate the influence of the home environment, defined as family socioeconomic status (SES) (parent education level, household income), student resource-mediated SES (access to nutritional resources and cognitively stimulating experiences), reading ability, and difficulty with homework on quality of life in children and adolescents residing in urban and suburban areas in Hangzhou City, Zhejiang Province, China. This study included 3200 Grade 3–6 students from 8 elementary schools in Hangzhou City. Assessments included questionnaires that evaluated student quality of life, family SES, resource-mediated SES (dietary behavior and the home literacy environment), reading ability, and difficulty with homework. The effects of the home environment on student quality of life were analyzed by univariate analysis, multiple linear regression analysis, and structural equation modeling. Overall, 80.6% of students had a medium or better quality of life. Young age (Grade 3 or 4), female sex, household income of 10000–15000 RMB, high breakfast consumption, daily intake of fruit, a balanced diet, and good reading habits were positively correlated with student quality of life (P < 0.05), while overuse of electronic devices was negatively correlated with quality of life (P < 0.05). Dietary behaviors, home literacy environment, and student reading ability and difficulty with homework directly affected quality of life. Family SES indirectly affected student quality of life. Children and adolescents in China should have access to good nutrition and cognitively stimulating experiences to enhance their well-being and provide them with social and academic advantages.
Analysis of Witnesses in the Steem Blockchain
Authors: Guidi Barbara , Michienzi Andrea , Ricci Laura
Published: April 2021

Online Social Networking platforms (OSNs) have become part of people’s everyday life and their usage covers the deep-rooted need for communication among humans. During recent years, as people are questioning more and more OSN service providers, a new generation of proposals, based on blockchain became very popular thanks to the ethics adopted by these platforms. Steemit is the most important blockchain-based social networking site, which integrates, as main novelty an economic layer to the social media service. Steemit is implemented on top of Steem which, as in other blockchains, awards miners of the blocks with cryptocurrency. Steem miners, called witnesses, are not chosen based on the solution of a mathematical problem, as in Proof of Work based systems, but must be voted by other users. In this work, we decide to study the witnesses on Steem and their contribution to the social platform Steemit, and their social impact. We performed a set of analyses to shred light concerning their behaviour and to understand how they are socially perceived by other users. Analyses show an important social impact but, at the same time, some of them have a negative social impact. Their discussion is polarized towards content concerning Steem, Steemit, witnesses, and other platforms hosted on Steem.
Recovery and exit of zombie firms in Portugal
Authors: Carreira Carlos , Teixeira Paulino , Nieto-Carrillo Ernesto
Published: April 2021

The resources sunk in zombie firms have risen over the last two decades, hampering productivity growth in developed economies. In this paper, we examine the recovery and exit of zombie firms among small- and medium-sized enterprises (SME), as well as the determinants of these transitions. To our knowledge, this is the first study on the determinants of the probability of a zombie recovering or exiting in a European context. The study also contributes to the discussion of the definition of zombie firms. Based on a panel of Portuguese manufacturing and services firms covering the 2004–2017 period, we do find a widespread presence of zombies. As expected, they are relatively less productive than non-zombies, while the probability of transition into recovery and exit is relatively low, which we interpret as evidence in favour of the presence of high barriers to firm mobility. In turn, the regression results show that downsizing and restructuring, as well as debt restructuring, are crucial in enhancing recovery of zombie firms. These are non-trivial results from the perspective of managers and policy makers. We performed several exercises using alternative definitions of zombie firms and estimation techniques and found that our findings are robust.

Plain English Summary A 1% decline in the share of highly indebted and unprofitable firms (i.e. zombies) is estimated to increase the average labour productivity by 3.1 percent. Recovery of zombies in particular can be enhanced by downsizing and restructuring. Based on a very large panel of Portuguese small- and medium-sized manufacturing and services firms, covering the 2004–2017 period, we do find a widespread presence of zombie firms. Moreover, the chance of these firms to recover or exit is relatively low, an evidence of the presence of high barriers to firm mobility and resource misallocation. Our results have important managerial and policy implications: (1) a coordinated and holistic restructuring strategy (technological, operational and debt-related) is crucial to increase the likelihood of recovery of weak companies; (2) governments should formulate an adequate institutional framework in order to strengthen the selection of zombie firms, namely by designing more reallocation-friendly insolvency regimes and discouraging creditors to refinance unviable firms.
Status Report on COVID-19 Vaccines Development
Authors: Kumar Arun , Dowling William E. , Román Raúl Gómez , Chaudhari Amol , Gurry Celine , Le Tung Thanh , Tollefson Stig , Clark Carolyn E , Bernasconi Valentina , Kristiansen Paul A
Published: April 2021

Purpose of Review

The emergence of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has affected lives of billions of individuals, globally. There is an urgent need to develop interventions including vaccines to control the ongoing pandemic.

Recent Findings

Development of tools for fast-tracked testing including small and large animal models for vaccine efficacy analysis, assays for immunogenicity assessment, critical reagents, international biological standards, and data sharing allowed accelerated development of vaccines. More than 300 vaccines are under development and 9 of them are approved for emergency use in various countries, with impressive efficacy ranging from 50 to 95%. Recently, several new SARS-CoV-2 variants have emerged and are circulating globally, and preliminary findings imply that some of them may escape immune responses against previous variants and diminish efficacy of current vaccines. Most of these variants acquired new mutations in their surface protein (Spike) which is the antigen in most of the approved/under development vaccines.

In this review, we summarize novel and traditional approaches for COVID-19 vaccine development including inactivated, attenuated, nucleic acid, vector and protein based. Critical assessment of humoral and cell-mediated immune responses induced by vaccines has shown comparative immunogenicity profiles of various vaccines in clinical phases. Recent reports confirmed that some currently available vaccines provide partial to complete protection against emerging SARS-CoV-2 variants. If more mutated variants emerge, current vaccines might need to be updated accordingly either by developing vaccines matching the circulating strain or designing multivalent vaccines to extend the breadth.
An apple a day – how the platform economy impacts value creation in the healthcare market
Authors: Gleiss Alexander , Kohlhagen Marco , Pousttchi Key
Published: April 2021

The healthcare industry has been slow to adopt new technologies and practices. However, digital and data-enabled innovations diffuse the market, and the COVID-19 pandemic has recently emphasized the necessity of a fundamental digital transformation. Available research indicates the relevance of digital platforms in this process but has not studied their economic impact to date. In view of this research gap and the social and economic relevance of healthcare, we explore how digital platforms might affect value creation in this market with a particular focus on Google, Apple, Facebook, Amazon, and Microsoft (GAFAM). We rely on value network analyses to examine how GAFAM platforms introduce new value-creating roles and mechanisms in healthcare through their manifold products and services. Hereupon, we examine the GAFAM-impact on healthcare by scrutinizing the facilitators, activities, and effects. Our analyses show how GAFAM platforms multifacetedly untie conventional relationships and transform value creation structures in the healthcare market.
Welding of high-entropy alloys and compositionally complex alloys—an overview
Authors: Rhode Michael , Richter Tim , Schroepfer Dirk , Manzoni Anna Maria , Schneider Mike , Laplanche Guillaume
Published: April 2021

High-entropy alloys (HEAs) and compositionally complex alloys (CCAs) represent new classes of materials containing five or more alloying elements (concentration of each element ranging from 5 to 35 at. %). In the present study, HEAs are defined as single-phase solid solutions; CCAs contain at least two phases. The alloy concept of HEAs/CCAs is fundamentally different from most conventional alloys and promises interesting properties for industrial applications (e.g., to overcome the strength-ductility trade-off). To date, little attention has been paid to the weldability of HEAs/CCAs encompassing effects on the welding metallurgy. It remains open whether welding of HEAs/CCAs may lead to the formation of brittle intermetallics and promote elemental segregation at crystalline defects. The effect on the weld joint properties (strength, corrosion resistance) must be investigated. The weld metal and heat-affected zone in conventional alloys are characterized by non-equilibrium microstructural evolutions that most probably occur in HEAs/CCAs. The corresponding weldability has not yet been studied in detail in the literature, and the existing information is not documented in a comprehensive way. Therefore, this study summarizes the most important results on the welding of HEAs/CCAs and their weld joint properties, classified by HEA/CCA type (focused on CoCrFeMnNi and AlxCoCrCuyFeNi system) and welding process.
The Book of Llandaf as a Historical Source
Authors: Sims-Williams Patrick
Published: April 2021

Revisionist approach to the question of the authenticity - or not - of the documents in the Book of Llandaf.
From Google Doodles to Facebook: Nostalgia and Visual Reconstructions of the Past in Nigeria
Authors: Yékú James , Ojebode Ayobami
Published: April 2021

In June 2019, Google announced plans to connect Africa to Europe through an undersea internet cable project named Equiano. As a techno-commercial platform, Google’s gesture warrants scrutiny and propels this essay’s analyses of the political connections of Internet spaces that also enable a visual turn in the scholarship of African history. Using the Google search engine and Facebook, Yékú and Ojebode stress the embeddedness of digital technologies in cultural meanings that include visual narratives that visibilize government’s ahistoricism. They conclude by foregrounding the digital labors of Nigerian digital subjects who deploy historical photographs on Facebook as expressions of performative nostalgia.
Optimal fluid stretching for mixing-limited reactions in rough channel flows
Authors: Yoon Seonkyoo , Dentz Marco , Kang Peter K.
Published: April 2021

We study the reactive displacement of two miscible fluids in channel flows and establish a quantitative link between fluid stretching and chemical reactivity. At the mixing interface, the two fluids react according to the instantaneous irreversible bimolecular reaction

$A + B \rightarrow C$

. We simulate the advection–diffusion–reaction problem using a random walk based reactive particle method that is free of numerical dispersion. The relative contributions of stretching and diffusion to mixing-limited reaction is controlled by changing the Péclet number, and the channel roughness is also systematically varied. We observe optimal ranges of fluid stretching that maximize reactivity, which are captured by a Lagrangian stretching measure based on an effective time period that honours the stretching history. We show that the optimality originates from the competition between the enhanced mixing by fluid stretching and the mass depletion of the reactants. We analytically derive the spatial distribution of reaction products using a lamellar formulation and successfully predict the optimal ranges of fluid stretching, which are consistent across different levels of channel roughness. These findings provide a mechanistic understanding of how the interplay between fluid stretching, diffusion and channel roughness controls mixing-limited reactions in rough channel flows, and show how reaction hot spots can be predicted from the concept of optimal fluid stretching.
Should you follow your gut? The impact of expertise on intuitive hiring decisions for complex jobs
Authors: Vincent Vinod U. , Guidice Rebecca M. , Mero Neal P.
Published: April 2021

As jobs become increasingly complex, organizations are challenged with finding effective ways to select and hire successful employees. The high level of uncertainty generally associated with hiring decisions is greater for complex jobs where it is difficult to identify the predictors of good job performance. Intuition research has found expert intuition to be effective in highly uncertain decision environments. However, most employment selection research dismisses the use of intuition and argues that even expert interviewers should not rely on their intuition. To bridge the two research streams, this paper addresses the research question: for complex jobs, can the intuition of expert decision-makers enhance the effectiveness of hiring decisions? The hypotheses were tested via an experimental study design using expert and nonexpert interviewer samples. The results demonstrate that, when recruiting for complex jobs, interviewer expertise does increase the quality of intuitive hiring decisions.
Learning to Detain Asylum Seekers and the Growth of Mass Immigration Detention in the United States
Authors: Ghosh Smita , Hoopes Mary
Published: April 2021

Drawing upon an analysis of congressional records and media coverage from 1981 to 1996, this article examines the growth of mass immigration detention. It traces an important shift during this period: while detention began as an ad hoc executive initiative that was received with skepticism by the legislature, Congress was ultimately responsible for entrenching the system over objections from the agency. As we reveal, a critical component of this evolution was a transformation in Congress’s perception of asylum seekers. While lawmakers initially decried their detention, they later branded them as dangerous. Lawmakers began describing asylum seekers as criminals or agents of infectious diseases in order to justify their detention, which then cleared the way for the mass detention of arriving migrants more broadly. Our analysis suggests that they may have emphasized the dangerousness of asylum seekers to resolve the dissonance between their theoretical commitments to asylum and their hesitance to welcome newcomers. In addition to this distinctive form of cognitive dissonance, we discuss a number of other implications of our research, including the ways in which the new penology framework figured into the changing discourse about detaining asylum seekers.
Trophic ecology and foraging areas of cetaceans sampled in the coastal waters of south-eastern Brazil assessed through skinδ13C andδ15N
Authors: Paschoalini Victor Uber , Troina Genyffer Cibele , Campos Laura Busin , Santos Marcos César de Oliveira
Published: April 2021

We investigated the habitat use and feeding ecology of 10 cetacean species encountered along the south-eastern coast of Brazil (24–26°S) using carbon (δ13C) and nitrogen (δ15N) stable isotopes. Hierarchical cluster analysis distinguished two main groups based on their isotopic patterns. One group included migratory baleen whales (Megaptera novaeangliaeandEubalaena australis) with the lowestδ13C andδ15N values, reflecting baseline isotopic values of their Subantarctic feeding grounds and consumption of lower trophic level prey. Resident species and those occasionally occurring in Brazilian coastal waters highly differed from the migratory whales in their isotopic values. In this group,Tursiops truncatushad the highestδ13C andδ15N values, indicating coastal habits and relatively higher trophic position. Similarδ13C values were observed inSotalia guianensis,Pontoporia blainvillei,Orcinus orcaandSteno bredanensis. However, the former two species had lowerδ15N values than the latter two, indicating different trophic positions. The relatively lowerδ13C values observed inStenella frontalissuggest greater influence of pelagic prey in their diet. Furthermore, the lowerδ13C values observed inDelphinus delphisandBalaenoptera edeniwere associated with upwelling events that occur along the region, affecting the isotopic values of their main prey. JuvenileM. novaeangliaehad higherδ13C andδ15N than the adults, which may indicate feeding in areas with different isoscapes and consumption of pelagic schooling fish with relatively higher trophic levels than krill. This study provides preliminary information that are useful to understand the habitat use and coexistence of cetacean species occurring in south-eastern Brazil.
Path planning method for unmanned underwater vehicles eliminating effect of currents based on artificial potential field
Authors: Zhu Danjie , Yang Simon X.
Published: April 2021

To eliminate the effect of ocean currents for optimal path planning for unmanned underwater vehicles (UUVs) in the underwater environment, an intelligent algorithm is designed and proposed in this paper. The algorithm consists of two parts: an artificial potential field-based algorithm that derives the shortest path and avoids collision accidents; and an adjusting function that eliminates the effect of ocean currents. The planning results of the intelligent algorithm are presented in detail, and compared with the conventional algorithm that does not consider the effect of currents. The effectiveness of the optimised path planning method given in this paper is proved.
Monitoring and evaluation of COVID-19 response in the WHO African region: challenges and lessons learned
Authors: Impouma Benido , Wolfe Caitlin M. , Mboussou Franck , Farham Bridget , Saturday Tessa , Pervilhac Cyril , Bishikwabo Nsarhaza , Mlanda Tamayi , Muhammad Arish Bukhari , Moussana Fleury , Talisuna Ambrose , Karamagi Humphrey , Keiser Olivia , Flahault Antoine , Cabore Joseph , Moeti Matshidiso
Published: April 2021

Monitoring and evaluation (M&E) is an essential component of public health emergency response. In the WHO African region (WHO AFRO), over 100 events are detected and responded to annually. Here we discuss the development of the M&E for COVID-19 that established a set of regional and country indicators for tracking the COVID-19 pandemic and response measures. An interdisciplinary task force used the 11 pillars of strategic preparedness and response to define a set of inputs, outputs, outcomes and impact indicators that were used to closely monitor and evaluate progress in the evolving COVID-19 response, with each pillar tailored to specific country needs. M&E data were submitted electronically and informed country profiles, detailed epidemiological reports, and situation reports. Further, 10 selected key performance indicators were tracked to monitor country progress through a bi-weekly progress scoring tool used to identify priority countries in need of additional support from WHO AFRO. Investment in M&E of health emergencies should be an integral part of efforts to strengthen national, regional and global capacities for early detection and response to threats to public health security. The development of an adaptable M&E framework for health emergencies must draw from the lessons learned throughout the COVID-19 response.
Spring-planted cover crops for weed control in soybean
Authors: Koehler-Cole Katja , Proctor Christopher A. , Elmore Roger W. , Wedin David A.
Published: April 2021

Replacing tillage with cover crops (CC) for weed management in corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] systems with mechanical weed control has many soil health benefits but in the western Corn Belt, CC establishment after harvest is hampered by cold temperatures, limited labor and few compatible CC species. Spring-planted CC may be an alternative, but information is lacking on suitable CC species. Our objective was to evaluate four spring-planted CC with respect to biomass production and weed suppression, concurrent with CC growth and post-termination. Cover crop species tested were oat (Avena sativa L.), barley (Hordeum vulgare L.), brown mustard [Brassica juncea (L.) Czern.] and yellow mustard (Brassica hirta Moench). They were compared to no-CC treatments that were either tilled pre- and post-planting of soybean (no-CC tilled) or not tilled at all (no-CC weedy). CC were planted in late March to early April, terminated 52–59 days later using an undercutter, and soybean was planted within a week. The experiment had a randomized complete block design with four replications and was repeated for 3 years. Mustards and small grains produced similar amounts of biomass (1.54 Mg ha−1) but mustard biomass production was more consistent (0.85–2.72 Mg ha−1) than that of the small grains (0.35–3.81 Mg ha−1). Relative to the no-CC weedy treatment, mustards suppressed concurrent weed biomass in two out of 3 years, by 31–97%, and small grains suppressed concurrent weed biomass in only 1 year, by 98%.

Six weeks after soybean planting, small grains suppressed weed biomass in one out of 3 years, by 79% relative to the no-CC weedy treatment, but mustards did not provide significant weed suppression. The no-CC tilled treatment suppressed weeds each year relative to the no-CC weedy treatment, on average 87%. The ineffective weed control by CC reduced soybean biomass by about 50% six weeks after planting. While spring-planted CC have the potential for pre-plant weed control, they do not provide adequate early season weed suppression for soybean.
InterCarb: A Community Effort to Improve Interlaboratory Standardization of the Carbonate Clumped Isotope Thermometer Using Carbonate Standards
Authors: Bernasconi S. M. , Daëron M. , Bergmann K. D. , Bonifacie M. , Meckler A. N. , Affek H. P. , Anderson N. , Bajnai D. , Barkan E. , Beverly E. , Blamart D. , Burgener L. , Calmels D. , Chaduteau C. , Clog M. , Davidheiser‐Kroll B. , Davies A. , Dux F. , Eiler J. , Elliott B. , Fetrow A. C. , Fiebig J. , Goldberg S. , Hermoso M. , Huntington K. W. , Hyland E. , Ingalls M. , Jaggi M. , John C. M. , Jost A. B. , Katz S. , Kelson J. , Kluge T. , Kocken I. J. , Laskar A. , Leutert T. J. , Liang D. , Lucarelli J. , Mackey T. J. , Mangenot X. , Meinicke N. , Modestou S. E. , Müller I. A. , Murray S. , Neary A. , Packard N. , Passey B. H. , Pelletier E. , Petersen S. , Piasecki A. , Schauer A. , Snell K. E. , Swart P. K. , Tripati A. , Upadhyay D. , Vennemann T. , Winkelstern I. , Yarian D. , Yoshida N. , Zhang N. , Ziegler M.
Published: April 2021

Increased use and improved methodology of carbonate clumped isotope thermometry has greatly enhanced our ability to interrogate a suite of Earth‐system processes. However, interlaboratory discrepancies in quantifying carbonate clumped isotope (Δ47) measurements persist, and their specific sources remain unclear. To address interlaboratory differences, we first provide consensus values from the clumped isotope community for four carbonate standards relative to heated and equilibrated gases with 1,819 individual analyses from 10 laboratories. Then we analyzed the four carbonate standards along with three additional standards, spanning a broad range of δ47 and Δ47 values, for a total of 5,329 analyses on 25 individual mass spectrometers from 22 different laboratories. Treating three of the materials as known standards and the other four as unknowns, we find that the use of carbonate reference materials is a robust method for standardization that yields interlaboratory discrepancies entirely consistent with intralaboratory analytical uncertainties. Carbonate reference materials, along with measurement and data processing practices described herein, provide the carbonate clumped isotope community with a robust approach to achieve interlaboratory agreement as we continue to use and improve this powerful geochemical tool. We propose that carbonate clumped isotope data normalized to the carbonate reference materials described in this publication should be reported as Δ47 (I‐CDES) values for Intercarb‐Carbon Dioxide Equilibrium Scale.
Low‐Altitude Ion Upflow Observed by EISCAT and its Effects on Supply of Molecular Ions in the Ring Current Detected by Arase (ERG)
Authors: Takada M. , Seki K. , Ogawa Y. , Keika K. , Kasahara S. , Yokota S. , Hori T. , Asamura K. , Miyoshi Y. , Shinohara I.
Published: April 2021

During the magnetic storm starting on September 7, 2017, the MEP‐i instrument onboard the Arase (ERG) satellite observed molecular ions (O2+/NO+/N2+) in the ring current. The molecular ions were observed by Arase in four orbits during this magnetic storm. This indicates that there was a continuous molecular ion supply from the ionosphere. During the storm main phase around the second Dst minimum (∼−100 nT) on September 8, 2017, the European Incoherent Scatter (EISCAT) radar observed the ion upflow (∼50–150 m s−1) in the low‐altitude (250–350 km) ionosphere together with strong ion heating up to >2,000 K. The convective electric field derived from the electron heating observed by EISCAT at an altitude of approximately 110 km was also enhanced by a factor of 2. The observations suggest that the additional ion heating at low altitudes helps to cause the fast upflow and transport molecular ions upward. The flux decreases from 280 to 350 km altitudes due to the dissociative recombination was estimated to be approximately two orders of magnitude. This resulted in significant molecular ion flux remaining at 350 km altitude. These results suggest that the low‐altitude ion upflow caused by the ion frictional heating enables molecular ions to escape to space against rapid loss by the dissociative recombination.
Distribution of Temperature and Strength in the Central Andean Lithosphere and Its Relationship to Seismicity and Active Deformation
Authors: Ibarra F. , Prezzi C. B. , Bott J. , Scheck‐Wenderoth M. , Strecker M. R.
Published: April 2021

We present three‐dimensional (3D) models of the present‐day steady‐state conductive thermal field and strength distribution in the lithosphere beneath the Central Andes. Our primary objective was to investigate the influence that the structure of the Central Andean lithosphere has on its thermal and rheological state, and the relationship between the latter and the active deformation in the region. We used our previous data‐driven and gravity‐constrained 3D density model as starting point for the calculations. We first assigned lithology‐derived thermal and rheological properties to the different divisions of the density model and defined temperature boundary conditions. We then calculated the 3D steady‐state conductive thermal field and the maximum differential stresses for both brittle and ductile behaviors. We find that the thickness and composition of the crust are the main factors affecting the modeled thermal field, and consequently also the strength distribution. The orogen is characterized by a thick felsic crust with elevated temperatures and a low integrated strength, whereas the foreland and forearc are underlain by a more mafic and thinner crust with lower temperatures and a higher integrated strength. We find that most of the intraplate deformation coincides spatially with the steepest strength gradients and suggest that the high potential energy of the orogen together with the presence of rheological lateral heterogeneities produce high compressional stresses and strong strain localization along the margins of the orogen. We interpret earthquakes within the modeled ductile field to be related to the weakening effect of long‐lived faults and/or the presence of seismic asperities.
A Dual‐Polarized Frequency Selective Rasorber With Wide Transmission Band
Authors: Jiao W. H. , Chang Y. M. , Wang L. , Wu W. J.
Published: April 2021

In this paper, a novel and simple dual‐polarized frequency‐selective rasorber (FSR) which has a wide absorption band including a wide transmission band was presented. Detailed equivalent circuit was derived to accurately predict the frequency responses of the structure. Based on reasonable equivalent analysis of a traditional metal grid structure, a modified structure with improved performance was proposed. The structure consists of a lossy frequency‐selective surface (FSS) constructed with metal rings connected by center loaded strips as the top layer, and a broadband transmission FSS at the bottom, while the two layers are separated by air. To validate our proposal, a prototype was fabricated and measured. The measured results are in good agreements with simulations under normal incidence, which indicates a broad absorption bandwidth of 80% that from 3.40 to 8.16 GHz; in the meantime, a wide transmission band with an insertion loss of less than −1.25 dB is ranging from 9.03 to 12.01 GHz. It should be pointed out that, the reflection from the whole structure in the operation band can be kept below −10 dB from 4.15 to 11.87 GHz.