bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid review of available evidence on the serial interval and generation
time of COVID-19
Authors: Griffin John , Casey Miriam , Collins Áine , Hunt Kevin , McEvoy David , Byrne Andrew , McAloon Conor , Barber Ann , Lane Elizabeth Ann , More SImon
Published: November 2020

The serial interval is the time between symptom onsets in an
infector–infectee pair. The generation time, also known as the generation
interval, is the time between infection events in an infector–infectee pair.
The serial interval and the generation time are key parameters for assessing
the dynamics of a disease. A number of scientific papers reported
information pertaining to the serial interval and/or generation time for
COVID-19.

Objective

Conduct a review of available evidence to advise on appropriate
parameter values for serial interval and generation time in national
COVID-19 transmission models for Ireland and on methodological issues
relating to those parameters.

Methods

We conducted a rapid review of the literature covering the period 1
January 2020 and 21 August 2020, following predefined eligibility
criteria. Forty scientific papers met our inclusion criteria and were
included in the review.

Results

The mean of the serial interval ranged from 3.03 to 7.6 days, based
on 38 estimates, and the median from 1.0 to 6.0 days (based on 15
estimates). Only three estimates were provided for the mean of the
generation time. These ranged from 3.95 to 5.20 days. One estimate of
5.0 days was provided for the median of the generation time.

Discussion

Estimates of the serial interval and the generation time are very
dependent on the specific factors that apply at the time that the data
are collected, including the level of social contact. Consequently, the
estimates may not be entirely relevant to other environments. Therefore,
local estimates should be obtained as soon as possible. Careful
consideration should be given to the methodology that is used. Real-time
estimations of the serial interval/generation time, allowing for
variations over time, may provide more accurate estimates of
reproduction numbers than using conventionally fixed serial
interval/generation time distributions.
Community psychosocial music intervention (CHIME) to reduce antenatal common mental disorder symptoms in The Gambia: a feasibility trial
Authors: Sanfilippo Katie Rose M , McConnell Bonnie , Cornelius Victoria , Darboe Buba , Huma Hajara B , Gaye Malick , Ceesay Hassoum , Ramchandani Paul , Cross Ian , Glover Vivette , Stewart Lauren
Published: November 2020

Objectives

Examine the feasibility of a Community Health Intervention through Musical Engagement (CHIME) in The Gambia to reduce common mental disorder (CMD) symptoms in pregnant women.

Design

Feasibility trial testing a randomised stepped-wedge cluster design.

Setting

Four local antenatal clinics.

Participants

Women who were 14–24 weeks pregnant and spoke Mandinka or Wolof were recruited into the intervention (n=50) or control group (n=74).

Intervention

Music-based psychosocial support sessions designed and delivered by all-female fertility societies. Sessions lasted 1 hour and were held weekly for 6 weeks. Delivered to groups of women with no preselection. Sessions were designed to lift mood, build social connection and provide health messaging through participatory music making. The control group received standard antenatal care.

Outcomes

Demographic, feasibility, acceptability outcomes and the appropriateness of the study design were assessed. Translated measurement tools (Self-Reporting Questionnaire (SRQ-20); Edinburgh Postnatal Depression Scale (EPDS)) were used to assess CMD symptoms at baseline, post-intervention and 4-week follow-up.

Results

All clinics and 82% of women approached consented to take part. A 33% attrition rate across all time points was observed. 72% in the intervention group attended at least three sessions. Audio and video analysis confirmed fidelity of the intervention and a thematic analysis of participant interviews demonstrated acceptability and positive evaluation. Results showed a potential beneficial effect with a reduction of 2.13 points (95% CI (0.89 to 3.38), p<0.01, n=99) on the SRQ-20 and 1.98 points (95% CI (1.06 to 2.90), p<0.01, n=99) on the EPDS at the post-intervention time point for the intervention group compared with standard care.

Conclusion

Results demonstrate that CHIME is acceptable and feasible in The Gambia. To our knowledge, CHIME is the first example of a music-based psychosocial intervention to be applied to perinatal mental health in a low- and middle-income country context.

Trial registration number

Pan African Clinical Trials Registry (PACTR201901917619299).
Associations between gestational diabetes mellitus and the neurodevelopment of offspring from 1 month to 72 months: study protocol for a cohort study
Authors: Li Chao , Zhou Ping , Cai Yixi , Peng Bin , Liu Yongfang , Yang Ting , Li Yinying , Hu Yirong , Fu Yajun , Wang Zhenming , Peng Hong , Zhang Yue , Chen Jie , Li Tingyu , Chen Li
Published: November 2020

Introduction

Gestational diabetes mellitus (GDM) is a common gestational disease and an important global public health problem. GDM may affect the short-term and long-term health of offspring, but the associations between GDM and the neurodevelopment of offspring of mothers with GDM (OGDM) are still unclear, and studies based on the Chinese population are lacking. We aim to determine the associations between GDM and the neurodevelopment of OGDM by studying a cohort of OGDM and offspring of non-GDM mothers.

Methods and analysis

The single-centre prospective cohort study is being conducted in China over 7 years. A total of 490 OGDM (GDM group) and 490 fromof healthy mothers (control group) will be enrolled during the same period. Baseline characteristics, neuropsychological development scores and clinical data at specific time points (at 0, 1, 3, 6, 12, 24, 36, 48, 60 and 72 months old) will be collected from the children in both groups until the age of 6 years. The associations between GDM and the neurodevelopment of OGDM from infancy to preschool age will be analysed using a multiple linear regression model adjusted for confounders. In addition, we will compare longitudinal data to further assess the effects of GDM on neurodevelopmental trajectories.

Ethics and dissemination

The study has been approved by the Ethics Committee of the Children’s Hospital of Chongqing Medical University (Approval Number: (2019) Institutional Review Board (IRB) (STUDY) No. 85). The findings of this study will be disseminated through open access journals, peer-reviewed journals and scientific meetings.

Trial registration number

NCT03997396.
Improving the Safety and Continuity Of Medicines management at Transitions of care (ISCOMAT): protocol for a process evaluation of a cluster randomised control trial
Authors: Powell Catherine , Breen Liz , Fylan Beth , Ismail Hanif , Alderson Sarah L , Gale Chris P , Gardner Peter , Farrin Amanda J , Alldred David P
Published: November 2020

Introduction

A key priority for the UK National Health Service and patients is to ensure that medicines are used safely and effectively. However, medication changes are not always optimally communicated and implemented when patients transfer from hospital into community settings. Heart failure is a common reason for admission to hospital. Patients with heart failure have a high burden of morbidity, mortality and complex pharmacotherapeutic regimens. The Improving the Safety and Continuity Of Medicines management at Transitions of care programme comprises a cluster randomised controlled trial which will test the effectiveness of a complex behavioural intervention aimed at improving medications management at the interface between hospitals discharge and community care. We will conduct a rigorous process evaluation to inform interpretation of the trial findings, inform implementation of the intervention on a wider scale and aid dissemination of the intervention.

Methods and analysis

The process evaluation will be conducted in six purposively selected intervention sites (ie, hospital trusts and associated community pharmacies) using a mixed-methods design. Fidelity and barriers/enablers of implementation of the Medicines at Transitions Intervention (MaTI) will be explored using observation, interviews (20 patients, 40 healthcare professionals), surveys and routine trial data collection on adherence to MaTI. A parallel mixed analysis will be applied. Qualitative data will be thematically analysed using Framework analysis and survey data will be analysed descriptively. Data will be synthesised, triangulated and mapped to the Consolidated Framework for Implementation Research where appropriate. The process evaluation commenced on June 2018 and is due to end on February 2021.

Ethics and dissemination

Approved by Research Ethics Committee and the UK Health Research Authority REC: 18/YH/0017/IRAS: 231 431. Findings will be disseminated via academic and policy conferences, peer-reviewed publications and social media.

Trial registration number

ISRCTN66212970.
MyCare study: protocol for a controlled trial evaluating the effect of a community-based intervention on psychosocial, clinical outcomes and hospital admission rates for adults with severe mental illness
Authors: O'Donnell Renée , Savaglio Melissa , Fast Debra , Vincent Ash , Vicary Dave , Skouteris Helen
Published: November 2020

Introduction

People with serious mental illness (SMI) often fail to receive adequate treatment. To provide a higher level of support, mental health systems have been reformed substantially to integrate mental healthcare into the community. MyCare is one such community-based mental health model of care. This paper describes the study protocol of a controlled trial examining the effect of MyCare on psychosocial and clinical outcomes and hospital admission and duration rates for adults with SMI.

Methods and analysis

This is a multisite non-randomised controlled trial with a 3, 6 and 12-month follow-up period. The study participants will be adults (18–64 years of age) with SMI recruited from Hobart, Launceston and the North-West of Tasmania. The treatment group will include adults who receive both the MyCare intervention and standard mental health support; the control group will include adults who receive only standard mental health support. The primary outcome includes psychosocial and clinical functioning and the secondary outcome will examine hospital admission rates and duration of stay. Mixed-effects models will be used to examine outcome improvements between intake and follow-up. This trial will generate the evidence needed to evaluate the effect of a community mental health support programme delivered in Tasmania, Australia. If MyCare results in sustained positive outcomes for adults with SMI, it could potentially be scaled up more broadly across Australia, addressing the inequity and lack of comprehensive treatment that many individuals with SMI experience.

Ethics and dissemination

This study has been approved by the Tasmanian Health and Medical Human Research Ethics Committee. The findings will be disseminated to participants and staff who delivered the intervention, submitted for publication in a peer-reviewed journal and shared at academic conferences.

Trial registration number

ACTRN12620000673943.
Computerised cognitive training in Parkinson’s disease: a protocol for a systematic review and updated meta-analysis
Authors: Gavelin Hanna Malmberg , Domellöf Magdalena , Leung Isabella , Neely Anna Stigsdotter , Finke Carsten , Lampit Amit
Published: November 2020

Introduction

Cognitive impairment is recognised as an important non-motor symptom in Parkinson’s disease (PD) and there is a need for evidence-based non-pharmacological interventions that may prevent or slow cognitive decline in this patient group. One such intervention is computerised cognitive training (CCT), which has shown efficacious for cognition across older adult populations. This systematic review aims to investigate the efficacy of CCT across cognitive, psychosocial and functional domains for people with PD and examine study and intervention design factors that could moderate CCT effects on cognition.

Methods and analysis

Randomised controlled trials investigating the effects of CCT in patients with PD without dementia, on cognitive, psychosocial or functional outcomes, will be included. The primary outcome is overall cognitive function. Secondary outcomes are domain-specific cognitive function, psychosocial functioning and functional abilities. We systematically searched MEDLINE, Embase and PsycINFO through 14 May 2020 to identify relevant literature. Risk of bias will be assessed using the revised Cochrane Risk of Bias tool. Effect sizes will be calculated as standardised mean difference of baseline to postintervention change (Hedges’ g) with 95% CI for each eligible outcome measure. Pooling of outcomes across studies will be conducted using random-effects models, accounting for dependency structure of effect sizes within studies. Heterogeneity will be assessed using τ2 and I2 statistic. Potential moderators, based on key study and intervention design factors, will be investigated using mixed-effects meta-regression models.

Ethics and dissemination

No ethical approval is required. The findings will be disseminated in a peer-reviewed scientific journal.

PROSPERO registration number

CRD42020185386.
Exploring the effectiveness of technology-based learning on the educational outcomes of undergraduate healthcare students: an overview of systematic reviews protocol
Authors: Romli Muhammad Hibatullah , Cheema Manraj Singh , Mehat Muhammad Zulfadli , Md Hashim Nur Fariesha , Abdul Hamid Hafizah
Published: November 2020

Introduction

Rapid technology development due to the introduction of Industrial Revolution 4.0 and Internet of Things has created a demand and gradual transition from traditional teaching and learning to technology-based learning in higher education, including healthcare education. The COVID-19 pandemic has accelerated this process, with educators now required to quickly adapt to and adopt such changes. The abundance of available systematic reviews has made the effectiveness of such approaches ambiguous especially in healthcare education. Therefore, a protocol of the overview of systematic reviews (OoSR) is planned to extrapolate the effectiveness of technology-based learning in undergraduate healthcare education.

Methods and analysis

Scopus, CINAHL, Academic Search Complete, Cochrane Library, MEDLINE and Psychology and Behavioral Sciences Collection databases were selected. Screening was conducted independently by at least two authors and the decision for inclusion was done through discussion or involvement of an arbiter against a predetermined criteria. Included articles will be evaluated for quality using A MeaSurement Tool to Assess systematic Reviews and Risk of Bias in Systematic Review tools, while primary systematic review articles will be cross-checked and reported for any overlapping using the ‘corrected covered area’ method. Only narrative synthesis will be employed according to the predefined themes into two major dimensions—theory and knowledge generation (focusing on cognitive taxonomy due to its ability to be generalised across disciplines), and clinical-based competence (focusing on psychomotor and affective taxonomies due to discipline-specific influence). The type of technology used will be identified and extracted.

Ethics and dissemination

The OoSR involves analysis of secondary data from published literature, thus ethical approval is not required. The findings will provide a valuable insight for policymakers, stakeholders, and researchers in terms of technology-based learning implementation and gaps identification. The findings will be published in several reports due to the extensiveness of the topic and will be disseminated through peer-reviewed publications and conferences.

PROSPERO registration number

CRD4202017974.
Trends in inequalities in Children Looked After in England between 2004 and 2019: a local area ecological analysis
Authors: Bennett Davara Lee , Mason Kate E , Schlüter Daniela K , Wickham S , Lai Eric TC , Alexiou Alexandros , Barr Ben , Taylor-Robinson David
Published: November 2020

Objective

To assess trends in inequalities in Children Looked After (CLA) in England between 2004 and 2019, after controlling for unemployment, a marker of recession and risk factor for child maltreatment.

Design

Longitudinal local area ecological analysis.

Setting

150 English upper-tier local authorities.

Participants

Children under the age of 18 years.

Primary outcome measure

The annual age-standardised rate of children starting to be looked after (CLA rate) across English local authorities, grouped into quintiles based on their level of income deprivation. Slope indices of inequality were estimated using longitudinal segmented mixed-effects models, controlling for unemployment.

Results

Since 2008, there has been a precipitous rise in CLA rates and a marked widening of inequalities. Unemployment was associated with rising CLA rates: for each percentage point increase in unemployment rate, an estimated additional 9 children per 100 000 per year (95% CI 6 to 11) became looked after the following year. However, inequalities increased independently of the effect of unemployment. Between 2007 and 2019, after controlling for unemployment, the gap between the most and least deprived areas increased by 15 children per 100 000 per year (95% CI 4 to 26) relative to the 2004–2006 trend.

Conclusions

The dramatic increase in the rate of children starting to be looked after has been greater in poorer areas and in areas more deeply affected by recession. But trends in unemployment do not explain the decade-long rise in inequalities, suggesting that other socioeconomic factors, including rising child poverty and reduced spending on children’s services, may be fuelling inequalities. Policies to safely reduce the CLA rate should urgently address the social determinants of child health and well-being.
Sex and age differences in clinically significant symptoms of depression and anxiety among people in Australia in the first month of COVID-19 restrictions: a national survey
Authors: Hammarberg Karin , Tran Thach , Kirkman Maggie , Fisher Jane
Published: November 2020

Objectives

To identify sex and age differences in clinically significant symptoms of depression and anxiety and the factors associated with these differences among adults in Australia during COVID-19-related restrictions.

Design

Anonymous online survey.

Setting

Australia.

Participants

Adults aged over 18 years living in Australia were eligible and 13 829 contributed complete data. Of these, 13 762 identified as female (10 434) or male (3328) and were included in analyses.

Interventions

None.

Outcome measures

Clinically significant symptoms of depression (≥10 on Patient Health Questionnaire 9) or anxiety (≥10 on Generalized Anxiety Disorder Scale 7 (GAD-7)), and experiences of irritability (GAD-7 item 6).

Results

Women were more likely than men to have clinically significant symptoms of depression (26.3% (95% CI 25.4 to 27.1) vs 20.1% (95% CI 18.7 to 21.5), p<0.001) and anxiety (21.8% (95% CI 21.0 to 22.6) vs 14.2% (95% CI 13.0 to 15.4), p<0.001) and to have experienced irritability in the previous fortnight (63.1% (95% CI 62.1 to 64.0) vs 51.4% (95% CI 49.7 to 53.2), p<0.001). They were also more likely than men to be doing unpaid work caring for children (22.8% (95% CI 22.0 to 23.6) vs 8.6% (95% CI 7.7 to 9.6), p<0.001) and dependent relatives (9.8% (95% CI 9.2 to 10.3) vs 5.7% (95% CI 4.9 to 6.5), p<0.001) which made significant contributions to the mental health outcomes of interest. Loss of employment, fear of contracting COVID-19 and feeling a severe impact of the restrictions were associated with poorer mental health in women and men of all ages.

Conclusions

Rates of clinically significant symptoms of depression and anxiety were higher among women than men. Rather than being intrinsically more vulnerable to mental health problems during the COVID-19 pandemic, the higher risk of symptoms of anxiety and depression among women may in part be explained by their disproportionate burden of unpaid caregiving.
Pan-Canadian learning outcomes in chemistry: a national snapshot
Authors: Loppnow Glen R. , Kamau Patrick , Vergis Elizabeth
Published: November 2020

Science, technology, engineering, and mathematics (STEM) students have, for generations, chosen university Bachelor of Science (B.Sc.) programs for themselves with little or no information about what they may get out of those programs, except as implicitly communicated within the culture and curriculum. However, in Canada, B.Sc. programs typically must explicitly state their program outcomes, at least in their initial submission to their respective provincial ministries of post-secondary education. We undertook a survey of all Canadian institutions’ B.Sc. programs in chemistry to provide a national snapshot of the values and priorities encompassed in institutional delivery of these programs. Our results show a definite preference for knowledge over other learning domains, particularly in translational skills, chemistry, science, and the laboratory. Alignment with provincial degree-level expectations, mostly standardized across Canada, is discussed as well.
Nitrogen and sulfur application effects on camelina seed yield, fatty acid composition, and nutrient removal
Authors: Obeng Eric , Obour Augustine K. , Nelson Nathan O. , Ciampitti Ignacio A. , Wang Donghai
Published: November 2020

Effective management of nitrogen (N) and sulfur (S) in camelina [Camelina sativa (L.) Crantz] production is important to ensure optimum seed yield and oil composition. The objectives of this study were to determine camelina seed yield and oil concentration and to estimate nutrient removal and N use efficiency (NUE) as influenced by N and S application. Field experiments were conducted to evaluate the effects of S rates (0 and 20 kg·ha−1) and N fertilizer rates (0, 22, 45, and 90 kg·ha−1) on camelina productivity and fatty acid composition over two growing seasons (2014 and 2015). Results showed S application had no effect on seed yield and oil concentration. Averaged across N rates, protein concentration increased with S application compared with the control. Seed yield showed quadratic response to N fertilizer application with maximum yield occurring at 54 kg N·ha−1; however, economic optimum N rate ranged from 18 to 43 kg N·ha−1. Nutrient removal, protein concentration, protein and oil yield, and estimated biodiesel were maximum at 45 kg N·ha−1. The maximum amounts of N, phosphorus, potassium, and S removed were 49, 8, 10, and 7 kg·ha−1, respectively. NUE and N agronomic efficiency decreased when N fertilizer rates were above 22 kg N·ha−1. Application of N or S had no effect on proportions of saturated fatty acid, monounsaturated fatty acid, and polyunsaturated fatty acids. Our findings suggest camelina required 18–43 kg N·ha−1 when grown in rain-fed systems in water-limited environments.
Towards a fundamental safe theory of composite Higgs and dark matter
Authors: Cacciapaglia Giacomo , Ma Teng , Vatani Shahram , Wu Yongcheng
Published: November 2020

We present a novel paradigm that allows to define a composite theory at the electroweak scale that is well defined all the way up to any energy by means of safety in the UV. The theory flows from a complete UV fixed point to an IR fixed point for the strong dynamics (which gives the desired walking) before generating a mass gap at the TeV scale. We discuss two models featuring a composite Higgs, Dark Matter and partial compositeness for all SM fermions. The UV theories can also be embedded in a Pati–Salam partial unification, thus removing the instability generated by the $$\text{ U }(1)$$

U

(
1
)

running. Finally, we find a Dark Matter candidate still allowed at masses of 260 GeV, or 1.5–2 TeV, where the latter mass range will be covered by next generation direct detection experiments.
Three-dimensional numerical simulation of ferrofluid magnetoconvection in cubical enclosure heated with an inner spherical hot block
Authors: Dhibi Boubaker , Ben-Beya Brahim
Published: November 2020

In this study, three-dimensional computational analysis is performed to investigate the magnetoconvection of ferrofluid ([Formula: see text]-water) within a cubical enclosure heated by an inner spherical hot block. The ferrofluid, considered as a working fluid, is modeled as a single-phase fluid. The inner spherical block is put at high temperature while all the remaining walls of the enclosure are exposed to low temperature. Two radii values ([Formula: see text] and [Formula: see text]) of the inner hot sphere are examined. Governing equations with corresponding boundary conditions are solved numerically applying a second-order accurate finite volume method on a staggered grid system, using an accelerated multigrid model. Simulations are carried out based on various flow-governing parameters such as Rayleigh number [Formula: see text], Hartmann number [Formula: see text] and ferrofluid nanoparticle volume fraction [Formula: see text]. The effects of the pertinent parameters in the performance of the system are also studied. The flow and thermal fields, the local and surface-averaged Nusselt numbers on the sphere and the enclosure for both configurations are detailed. The flow remains steady and laminar for all Rayleigh numbers regardless of the sphere radius. Obviously, heat transfer rate improves with [Formula: see text] augmentation and minimizes with Ha decrease. At the highest Ra and lowest Ha, higher inner sphere radius shows significantly better heat transfer rate (more than [Formula: see text]). Useful correlations are presented to quantify the surface-averaged heat transfer rate through the cubical enclosure.
Representations of ω-Lie algebras and tailed derivations of Lie algebras
Authors: Zhang Runxuan
Published: November 2020

We study the representation theory of finite-dimensional [Formula: see text]-Lie algebras over the complex field. We derive an [Formula: see text]-Lie version of the classical Lie’s theorem, i.e., any finite-dimensional irreducible module of a soluble [Formula: see text]-Lie algebra is 1-dimensional (1D). We also prove that indecomposable modules of some 3D [Formula: see text]-Lie algebras could be parametrized by the complex field and nilpotent matrices. We introduce the notion of a tailed derivation of a nonassociative algebra [Formula: see text] and prove that if [Formula: see text] is a Lie algebra, then there exists a one-to-one correspondence between tailed derivations of [Formula: see text] and 1D [Formula: see text]-extensions of [Formula: see text].
Large deviations for stochastic models of two-dimensional second grade fluids driven by Lévy Noise
Authors: Zhai Jianliang , Zhang Tusheng , Zheng Wuting
Published: November 2020

In this paper, we establish a Freidlin–Wentzell-type large deviation principle for stochastic models of two-dimensional second grade fluids driven by Lévy noise. The weak convergence method introduced by Budhiraja, Dupuis and Maroulas plays a key role.
Regularization of cylindrical processes in locally convex spaces
Authors: Fonseca-Mora Christian A.
Published: November 2020

Let [Formula: see text] be a locally convex space and let [Formula: see text] denote its strong dual. In this paper, we introduce sufficient conditions for the existence of a continuous or a càdlàg [Formula: see text]-valued version to a cylindrical process defined on [Formula: see text]. Our result generalizes many other known results on the literature and their different connections will be discussed. As an application, we provide sufficient conditions for the existence of a [Formula: see text]-valued càdlàg Lévy process version to a given cylindrical Lévy process in [Formula: see text].
Stability of Stainless Steel I-Section Beam-Columns at Elevated Temperatures
Authors: Kucukler Merih , Xing Zhe , Gardner Leroy
Published: November 2020

With the growing use of stainless steel in the construction and offshore industries, there is an increasing interest and need to study the performance of stainless structures at elevated temperatures. The behavior and design of stainless steel I-section beam-columns in fire is investigated in this paper, addressing a scarcity of previous research on this topic. Finite element (FE) models of stainless steel beam-columns, able to replicate their response at elevated temperatures, are created and validated; the validated models are then used to perform parametric studies to generate extensive benchmark structural performance data. The design rules set out in the European structural steel fire design standard EN 1993-1-2 are assessed and shown to provide rather inaccurate and often unsafe ultimate strength predictions for stainless steel I-section beam-columns in fire. New fire design rules for stainless steel beam-columns are put forward. It is shown that the new proposals are able to offer improved accuracy and design efficiency relative to the EN 1993-1-2 beam-column design rules. The reliability of the proposed design rules is also verified on the basis of the fire design reliability criteria set out by Kruppa [Eurocodes–Fire parts: Proposal for a methodology to check the accuracy of assessment methods, CEN TC 250, Horizontal Group Fire, Document no: 99/130 (1999)], thereby demonstrating the suitability of the proposed design rules for inclusion in the upcoming revised version of EN 1993-1-2.
Controllable Fabrication of Nano-NbN with Three-Dimensional Cotton like Structure for Oxygen Reduction Reaction
Authors: He Bo , Tian Feng , Yuan Shaofeng , Li Tianjun , Zhu Guochuan
Published: November 2020

A facial method is demonstrated here for the controllable fabrication of nano-NbN with three-dimensional cotton like structure. It is composed of two-step synthesis strategy and uses ammonia as nitrogen source. The prepared NbN has three-dimensional cotton like structure formed by nanoparticles with a size of around 20[Formula: see text]nm. It is found that the temperature of nitriding has a great influence on the size of crystal grain. 800∘C is the most appropriate temperature to form this special structure of nano-NbN. As a catalyst for oxygen reduction reaction, nano-NbN is discovered to have a significant property, which is much better than that of niobium nitride prepared from oxide precursor without any treatment. Inspired by this strategy, the electrocatalytic performance of transition metal nitrides in nanoscale can be better studied.
Signal Transduction in Hepatocellular Carcinoma: Insights from Zebrafish
Authors: Kumar Madan Mohan Udaya , Low Boon Chuan , Gong Zhiyuan
Published: November 2020

The zebrafish has been an increasingly popular animal model for human diseases as it offers the combined advantages compared to various animal models and cell based assays; in particular, the feasibility of high throughput studies as an economical vertebrate model. In this past decade, we and several other laboratories have developed various hepatocellular carcinoma (HCC) models using the zebrafish and demonstrated the conservation of HCC between zebrafish and human at both histopathological and molecular levels. In this review, we focus on the conservation of signal transductions during hepatocarcinogenesis between zebrafish and human. Based on existing zebrafish HCC models, indeed many alterations of signal pathways that cause human liver cancers can also result in HCC in zebrafish, such as Ras pathway, EGFR pathway, Wng/β-catenin pathway, TGF-β pathway, PI3K/AKT pathway, JAK/STAT pathway, Hippo pathway, src tyrosine kinase pathway, etc. In future, zebrafish may be used for better quantification of signaling molecules and thus to aid development of more effective therapeutic methods.
First and most northern occurrence of a thalattosuchian crocodylomorph from the Jurassic of the Isle of Skye, Scotland
Authors: Kean Kim J. , Foffa Davide , Johnson Michela M. , Young Mark T. , Greitens Gert , Brusatte Stephen L.
Published: November 2020

The Jurassic was a key interval for the evolution of dinosaurs, crocodylomorphs and many other vertebrate groups. In recent years, new vertebrate fossils have emerged from the Early–Middle Jurassic of the Isle of Skye, Scotland; however, much more is known about Skye's dinosaur fauna than its crocodylomorphs. Here we report new crocodylomorph material collected from Jurassic marine deposits at Prince Charlie's Cave on the NE coast of Skye. The specimen is a small cobble containing postcranial elements from an individual that is considerably larger in size than previous crocodylomorphs described from Skye. Based on features of the vertebrae and osteoderms, the specimen is assigned to Thalattosuchia, an extinct clade of semi-aquatic/pelagic crocodylomorphs. Specifically, the sub-circular and bean-shaped pit ornamentation on the dorsal surface of the osteoderms in alternating rows suggests affinities with the semi-aquatic lineage Teleosauroidea. Although the ornamentation pattern on the osteoderms is most similar to
Macrospondylus
(‘
Steneosaurus
’)
bollensis
, we conservatively assign the specimen to Teleosauroidea indeterminate. Regardless of its precise affinities and fragmentary nature, the specimen is the first thalattosuchian discovered in Scotland and is the most northerly reported Jurassic thalattosuchian globally, adding to our understanding of the palaeobiogeography and evolution of this group.

Thematic collection:
This article is part of the Early Career Research collection available at:
https://www.lyellcollection.org/cc/SJG-early-career-research
Can advanced type systems be usable? An empirical study of ownership, assets, and typestate in Obsidian
Authors: Coblenz Michael , Aldrich Jonathan , Myers Brad A. , Sunshine Joshua
Published: November 2020

Some blockchain programs (smart contracts) have included serious security vulnerabilities. Obsidian is a new typestate-oriented programming language that uses a strong type system to rule out some of these vulnerabilities. Although Obsidian was designed to promote usability to make it as easy as possible to write programs, strong type systems can cause a language to be difficult to use. In particular, ownership, typestate, and assets, which Obsidian uses to provide safety guarantees, have not seen broad adoption together in popular languages and result in significant usability challenges. We performed an empirical study with 20 participants comparing Obsidian to Solidity, which is the language most commonly used for writing smart contracts today. We observed that Obsidian participants were able to successfully complete more of the programming tasks than the Solidity participants. We also found that the Solidity participants commonly inserted asset-related bugs, which Obsidian detects at compile time.
Multiparty motion coordination: from choreographies to robotics programs
Authors: Majumdar Rupak , Yoshida Nobuko , Zufferey Damien
Published: November 2020

We present a programming model and typing discipline for complex multi-robot coordination programming. Our model encompasses both synchronisation through message passing and continuous-time dynamic motion primitives in physical space. We specify
continuous-time motion primitives
in an assume-guarantee logic that ensures compatibility of motion primitives as well as collision freedom. We specify global behaviour of programs in a
choreographic
type system that extends multiparty session types with jointly executed motion primitives, predicated refinements, as well as a
separating conjunction
that allows reasoning about subsets of interacting robots. We describe a notion of
well-formedness
for global types that ensures motion and communication can be correctly synchronised and provide algorithms for checking well-formedness, projecting a type, and local type checking. A well-typed program is
communication safe
,
motion compatible
, and
collision free
. Our type system provides a compositional approach to ensuring these properties.

We have implemented our model on top of the ROS framework. This allows us to program multi-robot coordination scenarios on top of commercial and custom robotics hardware platforms. We show through case studies that we can model and statically verify quite complex manoeuvres involving multiple manipulators and mobile robots---such examples are beyond the scope of previous approaches.
Featherweight go
Authors: Griesemer Robert , Hu Raymond , Kokke Wen , Lange Julien , Taylor Ian Lance , Toninho Bernardo , Wadler Philip , Yoshida Nobuko
Published: November 2020

We describe a design for generics in Go inspired by previous work on Featherweight Java by Igarashi, Pierce, and Wadler. Whereas subtyping in Java is nominal, in Go it is structural, and whereas generics in Java are defined via erasure, in Go we use monomorphisation. Although monomorphisation is widely used, we are one of the first to formalise it. Our design also supports a solution to The Expression Problem.
Persistent Owicki-Gries reasoning: a program logic for reasoning about persistent programs on Intel-x86
Authors: Raad Azalea , Lahav Ori , Vafeiadis Viktor
Published: November 2020

The advent of non-volatile memory (NVM) technologies is expected to transform how software systems are structured fundamentally, making the task of
correct
programming significantly harder. This is because ensuring that memory stores persist in the correct order is challenging, and requires low-level programming to flush the cache at appropriate points. This has in turn resulted in a noticeable
verification gap
.

To address this, we study the verification of NVM programs, and present
Persistent Owicki-Gries
(POG), the first program logic for reasoning about such programs. We prove the soundness of POG over the recent Intel-x86 model, which formalises the out-of-order persistence of memory stores and the semantics of the Intel cache line flush instructions. We then use POG to verify several programs that interact with NVM.
Polymorphic types and effects with Boolean unification
Authors: Madsen Magnus , van de Pol Jaco
Published: November 2020

We present a simple, practical, and expressive type and effect system based on Boolean constraints. The effect system extends the Hindley-Milner type system, supports parametric polymorphism, and preserves principal types modulo Boolean equivalence. We show how to support type inference by extending Algorithm W with Boolean unification based on the successive variable elimination algorithm.

We implement the type and effect system in the Flix programming language. We perform an in-depth evaluation on the impact of Boolean unification on type inference time and end-to-end compilation time. While the computational complexity of Boolean unification is NP-hard, the experimental results demonstrate that it works well in practice. We find that the impact on type inference time is on average a 1.4x slowdown and the overall impact on end-to-end compilation time is a 1.1x slowdown.
The anchor verifier for blocking and non-blocking concurrent software
Authors: Flanagan Cormac , Freund Stephen N.
Published: November 2020

Verifying the correctness of concurrent software with subtle synchronization is notoriously challenging. We present the Anchor verifier, which is based on a new formalism for specifying synchronization disciplines that describes both (1) what memory accesses are permitted, and (2) how each permitted access commutes with concurrent operations of other threads (to facilitate reduction proofs). Anchor supports the verification of both lock-based blocking and cas-based non-blocking algorithms. Experiments on a variety concurrent data structures and algorithms show that Anchor significantly reduces the burden of concurrent verification.
Towards a formal foundation of intermittent computing
Authors: Surbatovich Milijana , Lucia Brandon , Jia Limin
Published: November 2020

Intermittently powered devices enable new applications in harsh or inaccessible environments, such as space or in-body implants, but also introduce problems in programmability and correctness. Researchers have developed programming models to ensure that programs make progress and do not produce erroneous results due to memory inconsistencies caused by intermittent executions. As the technology has matured, more and more features are added to intermittently powered devices, such as I/O. Prior work has shown that all existing intermittent execution models have problems with repeated device or sensor inputs (RIO). RIOs could leave intermittent executions in an inconsistent state. Such problems and the proliferation of existing intermittent execution models necessitate a formal foundation for intermittent computing.

In this paper, we formalize intermittent execution models, their correctness properties with respect to memory consistency and inputs, and identify the invariants needed to prove systems correct. We prove equivalence between several existing intermittent systems. To address RIO problems, we define an algorithm for identifying variables affected by RIOs that need to be restored after reboot and prove the algorithm correct. Finally, we implement the algorithm in a novel intermittent runtime system that is correct with respect to input operations and evaluate its performance.
Knowing when to ask: sound scheduling of name resolution in type checkers derived from declarative specifications
Authors: Rouvoet Arjen , van Antwerpen Hendrik , Bach Poulsen Casper , Krebbers Robbert , Visser Eelco
Published: November 2020

There is a large gap between the specification of type systems and the implementation of their type checkers, which impedes reasoning about the soundness of the type checker with respect to the specification. A vision to close this gap is to automatically obtain type checkers from declarative programming language specifications. This moves the burden of proving correctness from a case-by-case basis for concrete languages to a single correctness proof for the specification language. This vision is obstructed by an aspect common to all programming languages: name resolution. Naming and scoping are pervasive and complex aspects of the static semantics of programming languages. Implementations of type checkers for languages with name binding features such as modules, imports, classes, and inheritance interleave collection of binding information (i.e., declarations, scoping structure, and imports) and querying that information. This requires scheduling those two aspects in such a way that query answers are stable—i.e., they are computed only after all relevant binding structure has been collected. Type checkers for concrete languages accomplish stability using language-specific knowledge about the type system.

In this paper we give a language-independent characterization of necessary and sufficient conditions to guarantee stability of name and type queries during type checking in terms of
critical edges in an incomplete scope graph
. We use critical edges to give a formal small-step operational semantics to a declarative specification language for type systems, that achieves soundness by delaying queries that may depend on missing information. This yields type checkers for the specified languages that are sound by construction—i.e., they schedule queries so that the answers are stable, and only accept programs that are name- and type-correct according to the declarative language specification. We implement this approach, and evaluate it against specifications of a small module and record language, as well as subsets of Java and Scala.
Fuzzing channel-based concurrency runtimes using types and effects
Authors: Stiévenart Quentin , Madsen Magnus
Published: November 2020

Modern programming languages support concurrent programming based on channels and processes. Channels enable synchronous and asynchronous message-passing between independent light-weight processes making it easy to express common concurrency patterns. The implementation of channels and processes in compilers and language runtimes is a difficult task that relies heavily on traditional and error-prone low-level concurrency primitives, raising concerns about correctness and reliability. In this paper, we present an automatic program generation technique to test such programming language implementations. We define a type and effect system for programs that communicate over channels and where every execution is guaranteed to eventually terminate. We can generate and run such programs, and if a program fails to terminate, we have found a bug in the programming language implementation. We implement such an automatic program generator and apply it to Go, Kotlin, Crystal, and Flix. We find two new bugs in Flix, and reproduce two bugs; one in Crystal and one in Kotlin.
DynamiTe: dynamic termination and non-termination proofs
Authors: Le Ton Chanh , Antonopoulos Timos , Fathololumi Parisa , Koskinen Eric , Nguyen ThanhVu
Published: November 2020

There is growing interest in termination reasoning for nonlinear programs and, meanwhile, recent dynamic strategies have shown they are able to infer invariants for such challenging programs. These advances led us to hypothesize that perhaps such dynamic strategies for nonlinear invariants could be adapted to learn recurrent sets (for non-termination) and/or ranking functions (for termination).

In this paper, we exploit dynamic analysis and draw termination and non-termination as well as static and dynamic strategies closer together in order to tackle nonlinear programs. For termination, our algorithm infers ranking functions from concrete transitive closures, and, for non-termination, the algorithm iteratively collects executions and dynamically learns conditions to refine recurrent sets. Finally, we describe an integrated algorithm that allows these algorithms to mutually inform each other, taking counterexamples from a failed validation in one endeavor and crossing both the static/dynamic and termination/non-termination lines, to create new execution samples for the other one.

We have implemented these algorithms in a new tool called DynamiTe. For nonlinear programs, there are currently no SV-COMP termination benchmarks so we created new sets of 38 terminating and 39 non-terminating programs. Our empirical evaluation shows that we can effectively guess (and sometimes even validate) ranking functions and recurrent sets for programs with nonlinear behaviors. Furthermore, we show that counterexamples from one failed validation can be used to generate executions for a dynamic analysis of the opposite property. Although we are focused on nonlinear programs, as a point of comparison, we compare DynamiTe's performance on linear programs with that of the state-of-the-art tool, Ultimate. Although DynamiTe is an order of magnitude slower it is nonetheless somewhat competitive and sometimes finds ranking functions where Ultimate was unable to. Ultimate cannot, however, handle the nonlinear programs in our new benchmark suite.
Random testing for C and C++ compilers with YARPGen
Authors: Livinskii Vsevolod , Babokin Dmitry , Regehr John
Published: November 2020

Compilers should not crash and they should not miscompile applications. Random testing is an effective method for finding compiler bugs that have escaped other kinds of testing. This paper presents Yet Another Random Program Generator (YARPGen), a random test-case generator for C and C++ that we used to find and report more than 220 bugs in GCC, LLVM, and the Intel® C++ Compiler. Our research contributions include a method for generating expressive programs that avoid undefined behavior without using dynamic checks, and generation policies, a mechanism for increasing diversity of generated code and for triggering more optimizations. Generation policies decrease the testing time to find hard-to-trigger compiler bugs and, for the kinds of scalar optimizations YARPGen was designed to stress-test, increase the number of times these optimizations are applied by the compiler by an average of 20% for LLVM and 40% for GCC. We also created tools for automating most of the common tasks related to compiler fuzzing; these tools are also useful for fuzzers other than ours.