bluuebunny/crossref_metadata_2025 huggingface dataset:
Patient preferences for physical therapy programs after a lower extremity fracture: a discrete choice experiment
Authors: McKibben Natasha S , Marchand Lucas S , Demyanovich Haley K , Healey Kathleen M , Zingas Nicolas , O'Connor Katherine , Slobogean Gerard P , O'Toole Robert V , O'Hara Nathan N
Published: October 2023

Objective

To quantify patients’ preferences for physical therapy programmes after a lower extremity fracture and determine patient factors associated with preference variation.

Design

Discrete choice experiment.

Setting

Level I trauma centre.

Participants

One hundred fifty-one adult (≥18 years old) patients with lower extremity fractures treated operatively.

Intervention

Patients were given hypothetical scenarios and asked to select their preferred therapy course when comparing cost, mobility, long-term pain, session duration, and treatment setting.

Main outcome measures

A multinomial logit model was used to determine the relative importance and willingness to pay for each attribute.

Results

Mobility was of greatest relative importance (45%, 95% CI: 40% to 49%), more than cost (23%, 95% CI: 19% to 27%), long-term pain (19%, 95% CI: 16% to 23%), therapy session duration (12%, 95% CI: 9% to 5%) or setting (1%, 95% CI: 0.2% to 2%). Patients were willing to pay US$142 more per session to return to their preinjury mobility level (95% CI: US$103 to US$182). Willingness to pay for improved mobility was higher for women, patients aged 70 years and older, those with bachelor’s degrees or higher and those living in less-deprived areas. Patients were willing to pay US$72 (95% CI: US$50 to US$93) more per session to reduce pain from severe to mild. Patients were indifferent between formal and independent home therapy (willingness to pay: −US$12, 95% CI: −US$33 to US$9).

Conclusions

Patients with lower extremity fractures highly value recovering mobility and are willing to pay more for postoperative physical therapy programmes that facilitate returning to their pre-injury mobility level. These patient preferences might be useful when prescribing and designing new techniques for postoperative therapy.
Identification of multicultural learning experiences following an international cross campus medical student exchange programme between the UK and Malaysia: a qualitative study
Authors: Rothwell Charlotte , Guilding Clare , Veasuvalingam Bhavani , McKeegan Kenneth , Illing Jan
Published: October 2023

Objectives

In an increasingly global society, there is a need to develop culturally competent doctors who can work effectively across diverse populations. International learning opportunities in undergraduate healthcare programmes show various benefits. In medical education, these occur predominantly towards the end of degree programmes as electives, with scant examples of programmes for preclinical students. This study set out to identify the multicultural learning experiences following an early year international medical student exchange programme between the UK and Malaysian campuses of one UK medical school.

Setting

Two cohorts of international exchange programme for second year medical students in the UK and Malaysia.

Design

Interpretivist qualitative design using semistructured interviews/focus groups with students and faculty.

Methods

Participants were asked about their learning experiences during and after the exchange. Data were recorded with consent and transcribed verbatim. Thematic analysis was used to analyse the data.

Results

Four themes were identified: (1) overall benefits of the exchange programme, (2) personal growth and development, (3) understanding and observing a different educational environment and (4) experiencing different healthcare systems.

Conclusion

The international exchange programme highlighted differences in learning approaches, students from both campuses gained valuable learning experiences which increased their personal growth, confidence, cultural competence, giving them an appreciation of a better work–life balance and effective time management skills. It is often a challenge to prepare healthcare professionals for work in a global multicultural workplace and we would suggest that exchange programmes early on in a medical curriculum would go some way to addressing this challenge.
Effect of caesarian section delivery on breastfeeding initiation in Nigeria: logit-based decomposition and subnational analysis of cross-sectional survey
Authors: Oyedele Oyewole K
Published: October 2023

Objectives

This study investigates caesarian section (CS) and vaginal delivery disparity, impact and contributions to timely initiation of breastfeeding (TIBF) to guide evidence-based strategy for improved breastfeeding practice.

Design and settings

A cross-sectional (population-based) analysis of 19 101 non-missing breastfeeding data from the 2018 Nigerian Demographic Health Survey collected via a two-stage stratified-random sampling across the 37 states in the 6 geopolitical-zones of Nigeria.

Participants

Complete responses from reproductive-age women (15–49 years) who had at least a childbirth in the last 5 years prior to the 2018 survey.

Main outcome measures

TIBF, that is, breastfeeding initiation within the first hour of newborn life is the outcome, CS is the exposure variable and explanatory factors were classified as; socio-demographic and obstetrics.

Methods

Descriptive statistics were reported and graphically presented. Bivariate χ2analysis initially assessed the relationship. Crude and adjusted logistic regression evaluated the likelihood and significance of multivariable association. Multivariate decomposition further quantified predictors’ contribution and importance. Statistical analysis was performed at a 95% confidence level in Stata V.17.

Results

44.1% and 20.2% of women with vaginal and CS delivery observed TIBF, respectively. Odds of TIBF were five times lower in women with CS delivery (adjusted OR ‘AOR’=0.21: 95% CI=0.16 to 0.26). TIBF odds increase among women who used skilled prenatal provider (AOR=1.29: 95% CI=1.15 to 1.45), had hospital delivery (AOR=1.34: 95% CI=1.18 to 1.52) and in rich wealth class (AOR=1.44: 95% CI=1.29 to 1.60), respectively. Rural residency, unwanted pregnancy and large child size at birth however reduces the odds. Partial skin-to-skin contacts contributed to about 54% (p<0.05) of the negative effect. TIBF is highest in Kano (3.4%) and lowest in Taraba (0.02%) with topmost impact in Bayelsa state (crude OR ‘COR’=63.9: 95% CI=28.2 to 144.9).

Conclusions

CS exposure reduced the odds of TIBF by fivefolds. Hence, the adverse effect of CS exposure on TIBF. Skin-to-skin contact can reduce the negative effect of CS on TIBF. Early mother−child contact peculiar to CS women is critical for improved breastfeeding practice.
Systematic review of Indigenous cultural safety training interventions for healthcare professionals in Australia, Canada, New Zealand and the United States
Authors: Hardy Billie-Jo , Filipenko Sam , Smylie Diane , Ziegler Carolyn , Smylie Janet
Published: October 2023

Objective

To synthesise and appraise the design and impact of peer-reviewed evaluations of Indigenous cultural safety training programmes and workshops for healthcare workers in Australia, Canada, New Zealand and/or the United States.

Design

Systematic review.

Data sources

Ovid Medline, Embase, PsycINFO, CINAHL, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Bibliography of Indigenous Peoples in North America, Applied Social Sciences Index & Abstracts, ERIC (Education Resources Information Center), International Bibliography of the Social Sciences, ProQuest Dissertations & Theses Global, Sociological Abstracts, and Web of Science’s Social Sciences Citation Index and Science Citation Index from 1 January 2006 to 12 May 2022.

Eligibility criteria

Studies that evaluated the outcomes of educational interventions for selecting studies: designed to improve cultural safety, cultural competency and/or cultural awareness for non-Indigenous adult healthcare professionals in Canada, Australia, New Zealand or the United States.

Data extraction and synthesis

Our team of Indigenous and allied scientists tailored existing data extraction and quality appraisal tools with input from Indigenous health service partners. We synthesised the results using an iterative narrative approach.

Results

2442 unique titles and abstracts met screening criteria. 13 full texts met full inclusion and quality appraisal criteria. Study designs, intervention characteristics and outcome measures were heterogeneous. Nine studies used mixed methods, two used qualitative methods and two used quantitative methods. Training participants included nurses, family practice residents, specialised practitioners and providers serving specific subpopulations. Theoretical frameworks and pedagogical approaches varied across programmes, which contained overlapping course content. Study outcomes were primarily learner oriented and focused on self-reported changes in knowledge, awareness, beliefs, attitudes and/or the confidence and skills to provide care for Indigenous peoples. The involvement of local Indigenous communities in the development, implementation and evaluation of the interventions was limited.

Conclusion

There is limited evidence regarding the effectiveness of specific content and approaches to cultural safety training on improving non-Indigenous health professionals’ knowledge of and skills to deliver quality, non-discriminatory care to Indigenous patients. Future research is needed that advances the methodological rigour of training evaluations, is focused on observed clinical outcomes, and is better aligned to local, regional,and/or national Indigenous priorities and needs.
Paediatric reference intervals and curves for haemoglobin and ferritin: protocol for a systematic review and meta-analysis
Authors: Bijelić Vid , Potter Beth , Parkin Patricia C , Momoli Franco , Liebman Mira , Hamid Jemila S
Published: October 2023

Introduction

Reference intervals and reference curves provide clinicians with a point of reference when evaluating patients’ laboratory test results. In practical applications, the 2.5th and 97.5th percentiles of healthy reference population are typically used as lower and upper reference limits. Guidelines outlining analytical and methodological steps involved in reference intervals and curves estimation are available and there have been large-scale world-wide initiatives to provide reference intervals and curves for children. However, there is a lack of synthesised evidence regarding the results of such initiatives in general, but specifically in iron-related biomarkers, ferritin (in serum and plasma) and haemoglobin. Objectives of this review are to identify studies that have produced reference intervals and curves for ferritin and haemoglobin in paediatric populations and to synthesise all available evidence. We also aim to quantify heterogeneity across reference intervals and curves and identify and elucidate sources of heterogeneity, including heterogeneity in the methods employed in their development.

Methods and analysis

Using a comprehensive search strategy, we will identify eligible studies. Following electronic databases will be searched from inception: EMBASE, MEDLINE, SCOPUS and The Cochrane Library. We will also perform grey literature search to capture unpublished reference intervals and curves from healthy cohorts. Two researchers will independently screen retrieved citations against eligibility criteria in two stages, focusing first on titles and abstracts and then on full-text articles. Studies that provide reference intervals and curves for ferritin and haemoglobin for paediatric population will be eligible. Data extraction will include study characteristics, characteristics of reference population, methodological and analytical considerations and estimated reference intervals and curves. We will consider narrative synthesis and quantitative synthesis when appropriate.

Ethics and dissemination

Ethical approval is not required as data from already published studies will be used. Results will be disseminated through peer-reviewed publications and conference presentations.

PROSPERO registration number

CRD42023399802.
Factors associated with vaccine coverage improvements in Senegal between 2005 and 2019: a quantitative retrospective analysis
Authors: Smalley Hannah K , Castillo-Zunino Francisco , Keskinocak Pinar , Nazzal Dima , Sakas Zoë M , Sarr Moussa , Freeman Matthew C
Published: October 2023

Objective

Senegal has demonstrated catalytic improvements in national coverage rates for early childhood vaccination, despite lower development assistance for childhood vaccines in Senegal compared with other low-income and lower-middle income countries. Understanding factors associated with historical changes in childhood vaccine coverage in Senegal, as well as heterogeneities across its 14 regions, can highlight effective practices that might be adapted to improve vaccine coverage elsewhere.

Design

Childhood vaccination coverage rates, demographic information and health system characteristics were identified from Senegal’s Demographic and Health Surveys (DHS) and Senegal national reports for years 2005–2019. Multivariate logistic and linear regression analyses were performed to determine statistical associations of demographic and health system characteristics with respect to childhood vaccination coverage rates.

Setting

The 14 administrative regions of Senegal were chosen for analysis.

Participants

DHS women’s survey respondents with living children aged 12–23 months for survey years 2005–2019.

Outcome measures

Immunisation with the third dose of the diphtheria-tetanus-pertussis vaccine (DTP3), widely used as a proxy for estimating immunisation coverage levels and the retention of children in the vaccine programme.

Results

Factors associated with childhood vaccination coverage include urban residence (β=0.61, p=0.0157), female literacy (β=1.11, p=0.0007), skilled prenatal care (β=1.80, p<0.0001) and self-reported ease of access to care when sick, considering travel distance to a healthcare facility (β=−0.70, p=0.0009) and concerns over travelling alone (β=−1.08, p<0.0001). Higher coverage with less variability over time was reported in urban areas near the capital and the coast (p=0.076), with increased coverage in recent years in more rural and landlocked areas.

Conclusions

Childhood vaccination was more likely among children whose mothers had higher literacy, received skilled prenatal care and had perceived ease of access to care when sick. Overall, vaccination coverage is high in Senegal and disparities in coverage between regions have decreased significantly in recent years.
Night work, season and alertness as occupational safety hazards in the Arctic: protocol for the Noralert observational crossover study among Norwegian process operators
Authors: Matre Dagfinn , Sallinen Mikael , Phillips Andrew J K , Moen Line Victoria , Nilsen Kristian Bernhard , Haugen Fred
Published: October 2023

Introduction

The objective of this study is to determine the effects of night work, Arctic seasonal factors and cold working environments on human functions relevant to safety. The study aims to quantify the contribution of (1) several consecutive night shifts, (2) seasonal variation on sleepiness, alertness and circadian rhythm and (3) whether a computational model of sleep, circadian rhythms and cognitive performance can accurately predict the observed sleepiness and alertness.

Methods and analysis

In an observational crossover study of outdoor and indoor workers (n=120) on a three-shift schedule from an industrial plant in Norway (70 °N), measurements will be conducted during the summer and winter. Sleep duration and quality will be measured daily by smartphone questionnaire, aided by actigraphy and heart rate measurements. Sleepiness and alertness will be assessed at regular intervals by the Karolinska Sleepiness Scale and the psychomotor vigilance test, respectively. Saliva samples will assess melatonin levels, and a blood sample will measure circadian time. Thermal exposures and responses will be measured by sensors and by thermography.

Ethics and dissemination

All participants will give written informed consent to participate in the study, which will be conducted in accordance with the Declaration of Helsinki. The Norwegian Regional Committee for Medical Research Ethics South-East D waivered the need for ethics approval (reference 495816). Dissemination plans include academic and lay publications, and partnerships with national and regional policymakers.
Diagnostic validity of MRI for central nervous system tuberculosis: protocol for a systematic review and meta-analysis
Authors: Shen Yanqin , Yao Liwei , Zhang Jinjuan , Lin Huihong
Published: October 2023

Introduction

Central nervous system tuberculosis (CNSTB) is a severe condition, sometimes associated with a poor prognosis. Early diagnosis of CNSTB remains challenging, considering that conventional methods lack sensitivity or might lead to certain side effects. Herein, we presented a protocol for a systematic review and meta-analysis to assess the diagnostic efficacy of MRI for CNSTB.

Methods and analysis

SinoMed, Wanfang database, China National Knowledge Infrastructure, Embase, the Cochrane Library and PubMed will be searched to identify studies reporting on the use of MRI in the diagnosis of CNSTB from database inception to December 2023. The following keywords will be applied: ‘Intracranial tuberculosis’, ‘Cerebral tuberculosis’, ‘Central nervous system tuberculosis’, ‘Spinal tuberculous arachnoiditis’ and ‘Magnetic Resonance Imaging’. Studies that evaluate the diagnostic accuracy of MRI for the diagnosis of CNSTB and report clear reference criteria will be included. Studies from which full true positive, false positive, false negative and true negative values cannot be extracted, those published in languages other than English or Chinese, abstracts not reporting the full text, and case reports will be excluded. Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) will be used to evaluate the methodological quality of each included study. Stata V.15.0 and RevMan V.5.3 will be used to perform a meta-analysis and generate forest plots and summary receiver operating characteristic curves. In case of significant heterogeneity between studies, possible sources of heterogeneity will be explored through subgroup and meta-regression analyses.

Ethics and dissemination

This research is based on public databases and does not require ethical approval. Results will be submitted for publication in a peer-reviewed journal.

PROSPERO registration number

CRD42023415690.
Quantifying the mental health and economic impacts of prospective Universal Basic Income schemes among young people in the UK: a microsimulation modelling study
Authors: Chen Tao , Reed Howard , Parra-Mujica Fiorella , Johnson Elliott Aidan , Johnson Matthew , O'Flaherty Martin , Collins Brendan , Kypridemos Chris
Published: October 2023

Objective

Universal Basic Income (UBI)—a largely unconditional, regular payment to all adults to support basic needs—has been proposed as a policy to increase the size and security of household incomes and promote mental health. We aimed to quantify its long-term impact on mental health among young people in England.

Methods

We produced a discrete-time dynamic stochastic microsimulation that models a close-to-reality open cohort of synthetic individuals (2010–2030) based on data from Office for National Statistics and Understanding Society. Three UBI scheme scenarios were simulated: Scheme 1—Starter (per week): £41 per child; £63 per adult over 18 and under 65; £190 per adult aged 65+; Scheme 2—Intermediate (per week): £63 per child; £145 per adult under 65; £190 per adult aged 65+; Scheme 3—Minimum Income Standard level (per week): £95 per child; £230 per adult under 65; £230 per adult aged 65+. We reported cases of anxiety and depression prevented or postponed and cost savings. Estimates are rounded to the second significant digit.

Results

Scheme 1 could prevent or postpone 200 000 (95% uncertainty interval: 180 000 to 210 000) cases of anxiety and depression from 2010 to 2030. This would increase to 420 000(400 000 to 440 000) for Scheme 2 and 550 000(520 000 to 570 000) for Scheme 3. Assuming that 50% of the cases are diagnosed and treated, Scheme 1 could save £330 million (£280 million to £390 million) to National Health Service (NHS) and personal social services (PSS), over the same period, with Scheme 2 (£710 million (£640 million to £790 million)) or Scheme 3 (£930 million (£850 million to £1000 million)) producing more considerable savings. Overall, total cost savings (including NHS, PSS and patients’ related costs) would range from £1.5 billion (£1.2 billion to £1.8 billion) for Scheme 1 to £4.2 billion (£3.7 billion to £4.6 billion) for Scheme 3.

Conclusion

Our modelling suggests that UBI could substantially benefit young people’s mental health, producing substantial health-related cost savings.
Effects of a physical activity promotion programme on body composition in emerging adults with physical inactivity: a study protocol of a randomised controlled trial
Authors: Xu Tao , Tao Yuexian , Chen Rong , Strachan Garry , Cai Xintong , Liu Chengyi
Published: October 2023

Introduction

A dramatic decline in physical activity may occur in emerging adulthood because of a major transition over the course of a life. The potential for implementing structured behaviour modification strategies to enhance risk-reducing clinical outcomes is widely recognised. The active participation of clients in the discussion and care process is crucial for optimising intervention outcomes and enhancing individuals’ motivation to adopt and maintain healthy behaviours. This study therefore aims to evaluate the effectiveness of a physical activity promotion programme based on the goal attainment theory in relation to emerging adults’ body composition, using a face-to-face and e-health blended interventions.

Methods and analysis

A two-arm, double-blind, randomised, controlled study will be conducted in 114 university students aged 18–25 years with physical inactivity. The intervention assignment will be blind to study participants, outcome assessors and study statisticians. A goal achievement theory-based physical activity promotion programme is developed in this study, which is a 16-week, face-to-face and e-health-blended physical activity promotion intervention. After informed consent, participants will be randomly assigned to either a control group or a treatment group before the start of the study. The primary outcome is body composition (ie, skeletal muscle mass, body fat mass, body mass index and body fat percentage). Other outcomes include physical activity level, goal attainment scale scores, exercise self-efficacy and motivation level, which will be assessed during the intervention (every 4 weeks) and at the 1 month follow-up. Continuous variables have means and SD, while categorical variables have frequencies and percentages. Independent-samples t-tests will be used to compare continuous variable changes. χ2tests will be used to compare categorical variable changes. Based on the baseline scores, analysis of covariance will compare the follow-up results.

Ethics and dissemination

This study was approved by the Ethics Committee of Hangzhou Normal University (ratification date: 14 November 2022, 2022059). The results of the study will be submitted for publication and dissemination in a peer-reviewed journal.

Trial registration number

NCT05697679.
Improving colorectal cancer screening disparities among Somali-speaking patients in an Internal Medicine Residency Clinic
Authors: Yao Rebecca , Sykora Daniel , Olson Emily M , Sanborn David , Himes Carina , Mohamed Ahmed Shafii , Matulis John
Published: October 2023

Colorectal cancer (CRC) is the third-most lethal cancer in the USA, and early detection through screening is crucial for improving outcomes. However, significant disparities in access and utilisation of CRC screening exist among patients with limited English proficiency. Our Quality Improvement (QI) team developed and implemented a video, featuring a Somali-speaking physician, created with input from internal medicine (IM) residents, patient education experts and community leaders to increase the rate of CRC screening uptake within a Somali-speaking population receiving primary care within an IM Residency Clinic. The baseline proportion of average-risk Somali-speaking patients who had successfully been screened for CRC was 46.3% (63/134). The proportion of patients agreeable to undergo CRC screening was assessed monthly from the beginning of video implementation (June 2022 to December 2022). We found that this intervention corresponded with a significant increase in willingness to undergo CRC screening from 36.4% to 100% during the early stages of intervention. At the end of our measurement timeframe, the proportion of the original population fully screened for CRC was 50.7% (68/134). Implementation of the video intervention was also assessed and determined to be minimally disruptive to the clinic flow.
FOXL2: a gene central to ovarian function
Authors: Mubeen Aysha , Parra-Herran Carlos
Published: October 2023

TheFOXL2(forkhead box L2) gene is located on chromosome 3 and encodes for forkhead box (FOX) family of transcription factors which play a critical role in various biological processes. GermlineFOXL2mutations have been identified in blepharophimosis/ptosis/epicanthus inversus syndrome. The somatic missense mutation inFOXL2(FOXL2C134W) is now known to be the defining molecular feature of adult-type granulosa cell tumour of the ovary, present in over 90% of cases of this tumour type. Immunohistochemistry forFOXL2is used as a marker of sex cord-stromal differentiation. However, expression is not restricted to lesions harbouringFOXL2mutations, and it is positive in a variety of sex cord-stromal proliferations other than adult-type granulosa cell tumour.
Exploration of associations between occupational exposures and current adult eczema
Authors: Lopez Diego J , Alif Sheikh , Dharmage Shyamali , Lodge Caroline J , Bui Dinh S , Le Moual Nicole , Waidyatillake Nilakshi T , Su John C , Abramson Michael , Walters E Haydn , Hamilton Garun S , Bowatte Gayan , Erbas Bircan , Benke Geza , Perret Jennifer , Lowe Adrian J
Published: October 2023

Objectives

There is a scarcity of evidence on occupational exposures that may increase eczema in adults. We aimed to investigate potential associations between occupational exposures and eczema in middle-aged adults.

Methods

A lifetime work history calendar was collected from the Tasmanian Longitudinal Health Study participants when they were at age 53. Their work history was collated with the occupational asthma-specific job exposure matrix to define ever-exposure and cumulative exposure unit-years since no eczema job exposure matrix is available. Eczema was determined using the report of flexural rash that was coming and going for at least 6 months in the last 12 months. Skin prick tests were used to further subgroup eczema and atopic eczema (AE) or non-AE (NAE). Logistic and multinomial regression models were used to investigate the associations.

Results

Eczema prevalence was 9.1%. Current occupational exposure to animals (adjusted OR, aOR=3.06 (95% CI 1.43 to 6.58)), storage mites (aOR=2.96 (95% CI 1.38 to 6.34)) and endotoxin (aOR=1.95 (95% CI 1.04 to 3.64)) were associated with increased risk of current eczema. Furthermore, increased odds of NAE were associated with current exposure to animals (aOR=5.60 (95% CI 1.45 to 21.7)) and storage mites (aOR=5.63 (95% CI 1.45 to 21.9)). Current exposures to isocyanates (aOR=5.27 (95% CI 1.17 to 23.7)) and acrylates (aOR=8.41 (95% CI 1.60 to 44.3)) were associated with AE. There was no evidence of associations between cumulative exposures and eczema prevalence. Cumulative exposure to metalworking fluids (aOR=1.10 (95% CI 1.01 to 1.22)) was associated with NAE and acrylates (aOR=1.24 (95% CI 1.04 to 1.46)) with AE.

Conclusions

In this exploratory assessment, multiple occupational exposures were associated with current eczema in middle-aged adults. Raising awareness and limiting these exposures during an individual’s productive working life will likely have various health benefits, including reducing eczema prevalence.
A SHANSEP approach to quantifying the behaviour of clayey soils on a constant shear drained stress path
Authors: Reid David , Fanni Riccardo , Fourie Andy
Published: October 2023

Assessing the risk of slope failures of earth structures comprising loose, saturated soils has seen increased focus recently owing to a series of prominent tailings and water dam failures. The potential for the triggering of slope instability by a rising phreatic surface—commonly referred to as the constant shear drained (CSD) stress path—has been well documented over the past few decades for sands and sandy soils under a wide range of loading modes. Alternatively, there has been limited CSD element testing of more clayey soils, with the available data rather showing a dilative tendency through the CSD stress path and mobilised strengths greater than the critical friction ratio, even for specimens commencing CSD shearing from an initially loose state. The current study expands on the CSD data of clayey soils by testing an iron ore tailings and kaolin clay in both triaxial and direct simple shear (DSS) devices, with an emphasis on the DSS. Owing to the tendency for the CSD stress path to result in an overconsolidated condition (i.e., unloading), the tests in the current study were interpreted in the SHANSEP framework given its frequent use to analyse clay behaviour. The results indicated that the SHANSEP framework can reasonably characterise some aspects of CSD behaviour of clays in DSS loading, with some caveats.
Holographic Einstein rings of a Gauss–Bonnet AdS black hole
Authors: Zeng Xiao-Xiong , He Ke-Jian , Pu Jin , Li Guo-Ping , Jiang Qing-Quan
Published: October 2023

Based on the AdS/CFT correspondence, we study the holographic Einstein image of a Gauss–Bonnet AdS black hole in the framework of wave optics. Our results show that for the absolute amplitude of total response function, there always exists the interference pattern when the scalar wave passes through black hole. And, the value of the amplitude depends closely on the properties of Gaussian source and spacetime geometry. More importantly, we also find that the holographic images always appears as a ring surrounded by the concentric stripe when observer located at the north pole. At other positions, this ring will change into a luminosity-deformed ring, or two light points. In addition, the influence of Gauss–Bonnet parameter $$\alpha $$
α
, wave source and optical system on the holographic image have been carefully addressed and the results show that the radius of ring is dependent of the Gauss–Bonnet parameter $$\alpha $$
α
but not dependent of wave source and optical system. The holographic images that different types of black holes have different features may shed deep insights on the existence of a gravity dual for a given material.
Modified Hawking temperature and entropy of Kerr–de Sitter black hole in Lorentz violation theory
Authors: Laxmi Y. Onika , Singh T. Ibungochouba , Meitei I. Ablu
Published: October 2023

In this paper, we discuss the tunneling of scalar particles near the event horizon of stationary and nonstationary Kerr–de Sitter black hole using Lorentz violation theory in curved space time. The modified form of Hamilton–Jacobi equation is derived from the Klein–Gordon equation by applying Lorentz violation theory. The Hawking temperatures derived from stationary and nonstationary Kerr–de Sitter black holes are modified due to Lorentz violation theory. It is noted that the change in Bekenstein–Hawking entropy and modified Hawking temperatures of stationary and nonstationary Kerr–de Sitter black hole not only depends on the black hole parameters but also on ether-like vectors [Formula: see text].
Dynamics Analysis of an 11-Dimensional Multiscale COVID-19 Model with Interval Parameters
Authors: Yang Qigui , Huang Jiabing
Published: October 2023

This paper investigates an 11-dimensional slow–fast system of multiscale COVID-19 model with interval parameters. For the slow subsystem, the local dynamics of disease-free equilibrium (DFE) and endemic equilibrium (EE) are studied by using the fast–slow theory. Two criteria of the existence of forward and backward bifurcations are further obtained. When the basic reproduction number [Formula: see text] is less than unity, we show that bistabilities of DFE and EE for [Formula: see text] can be caused by backward bifurcation. Thus, controlling [Formula: see text] below critical value [Formula: see text] is effective to eliminate endemic diseases. Meanwhile, the slow subsystem undergoes saddle-node bifurcation at [Formula: see text] and undergoes pitchfork bifurcation at [Formula: see text] for EE. Moreover, the stability and bifurcation of the multiscale full system are established. As an application, the numerical simulations of real data of COVID-19 in Hong Kong are used to verify these results, which show that increasing vaccination rate, improving vaccine effectiveness and decreasing the fraction of individuals in risky state 2 are necessary to control the COVID-19.
Singular Perturbation Analysis for a Holling–Tanner Model with Additive Allee Effect
Authors: Zhu Zirui , Liu Xingbo
Published: October 2023

In this article, a reaction–diffusion predator–prey equation with additive Allee effect acting on prey is investigated by twice singular perturbation analysis. Our focus is to study the traveling fronts of predator invasion under the assumption that the diffusion ability of the predator is much greater than that of the prey. Our results exhibit two kinds of traveling fronts for a Holling–Tanner system in two different limit cases. And these traveling fronts correspond to the heteroclinic connections between a saddle and either a stable node or a stable focus. In addition, we show that heteroclinic connections are formed in different ways for different limit cases. One is formed on the slow manifold, which has one time scale. While the other is formed by the intersection of the slow manifold and the fast manifold, which has two time scales. Furthermore, the existence of traveling front solutions in different limit cases is demonstrated through theoretical analysis and numerical simulation. The main tools are geometric singular perturbation theory and Bendixson’s criteria.
Normal Form and Unfolding of Vector Field with Codimension-3 Triple Hopf Bifurcation
Authors: Li Minlong , Xia Yibo , Bi Qinsheng
Published: October 2023

The universal unfolding of a normal form can be employed to reveal the general behaviors of a specific local bifurcation, while the computation of the normal form for high codimensional bifurcation still remains unsolved. This paper focuses on a vector field with codimension-3 triple Hopf bifurcation. Besides 1:1 internal resonance for two frequencies in semi-simple form, two cases are considered, corresponding to internal resonance and noninternal resonance between the first two frequencies and the third frequency, respectively. Based on a combination of center manifold and normal theory, all the coefficients in the normal form and the nonlinear transformation are derived explicitly in terms of the coefficients of the original vector field. Upon the recursive procedure established, a user friendly computer program can be easily developed using a symbolic computation language Maple to compute the coefficients up to an arbitrary order for a specific vector field with triple Hopf bifurcation. Furthermore, universal unfolding of the normal form is obtained, which can be used to display the topological structure in the neighborhood of bifurcation point. It is pointed out that different choices of the remaining terms in the nonlinear transformation may lead to different expressions of the normal form and the unfolding, which are qualitatively equivalent to each other.
Arnold Tongue-Like Structures and Coexisting Attractors in the Memristive Muthuswamy–Chua–Ginoux Circuit Model
Authors: Manchein Cesar , Berger Helena F. , Albuquerque Holokx A. , Mello Luis Fernando
Published: October 2023

The three-dimensional Muthuswamy–Chua–Ginoux (MCG) circuit model is a generalization of the paradigmatic canonical Muthuswamy–Chua circuit, where a physical memristor assumes the role of a thermistor, and it is connected in series with a linear passive capacitor, a linear passive inductor, and a nonlinear resistor. The physical memristor presents an electrical resistance which is a function of temperature. Nowadays, the MCG circuit model has gained considerable attention due to the lack of extensive numerical explorations and their distinct dynamical properties, exemplified by phenomena such as the transition from torus breakdown to chaos, giving rise to a double spiral attractor associated to independent period-doubling cascades. In this contribution, the complex dynamics of the MCG circuit model is studied in terms of the Lyapunov exponents spectra, Kaplan–Yorke (KY) dimension, and the number of local maxima (LM) computed in one period of oscillation, as two parameters are simultaneously varied. Using the Lyapunov spectra to distinguish different dynamical regimes, KY dimension to estimate the attractors’ dimension, and the number of LM to characterize different periodic attractors, we construct high-resolution two-dimensional stability diagrams considering specific ranges of the parameter pairs [Formula: see text]. These parameters are associated with the inverse of the capacitance in the passive capacitor, and the heat capacitance and dissipation constant of the thermistor, respectively. Unexpectedly, we identify sequences of infinite self-organized generic stable periodic structures (SPSs) and Arnold tongues-like structures (ATSs) merged into chaotic dynamics domains, and the coexistence of different attracting sets (attractors) for the same parameter combinations and different initial conditions (multistability). We explore the multistable dynamics using the stability analysis and computation of Lyapunov coefficients, the inspection of the coexisting attractors, bifurcations diagrams, and basins of attraction. The periods of the ATSs and a particular sequence of shrimp-shaped SPSs obey specific generating and recurrence rules responsible for the bifurcation cascades. As the MCG circuit model has the crucial properties presented by the usual Muthuswamy–Chua circuit model, specific properties explored in our study should be helpful in real problems involving circuits with the presence of physical memristor playing the role of thermistors.
Global Attractor in the Positive Quadrant of the Lotka–Volterra System in ℝ2
Authors: Llibre Jaume , Mancilla-Martínez Y. Paulina
Published: October 2023

We characterize when the unique equilibrium point of the positive quadrant of the twodimensional Lotka–Volterra system is a global attractor in that quadrant. Additionally, we classify the phase portraits of this class of Lokta–Volterra system.
A Partitioned CAM Architecture with FPGA Acceleration for Binary Descriptor Matching
Authors: Soleimani Parastoo , Capson David W. , Li Kin Fun
Published: October 2023

An efficient architecture for image descriptor matching that uses a partitioned content-addressable memory (CAM)-based approach is proposed. CAM is frequently used in high-speed content-matching applications. However, due to its lack of functionality to support approximate matching, conventional CAM is not directly useful for image descriptor matching. Our modifications improve the CAM architecture to support approximate content matching for selecting image matches with local binary descriptors. Matches are based on Hamming distances computed for all possible pairs of binary descriptors extracted from two images. We demonstrate an FPGA-based implementation of our CAM-based descriptor-matching unit to illustrate the high matching speed of our design. The time complexity of our modified CAM method for binary descriptor matching is O(n). Our method performs binary descriptor matching at a rate of one descriptor per clock cycle at a frequency of 102 MHz. The resource utilization and timing metrics of several experiments are reported to demonstrate the efficacy and scalability of our design.
Distributed Scrum: A Case Meta-analysis
Authors: Santos Ronnie De Souza , Ralph Paul , Arshad Arham , Stol Klaas-Jan
Published: October 2023

Distributed Scrum adapts the Scrum project management framework for geographically distributed software teams. Experimentally evaluating the effectiveness of Distributed Scrum is impractical, but many case studies and experience reports describe teams and projects that used Distributed Scrum. This article synthesizes the results of these cases using case meta-analysis, a technique for quantitatively analyzing qualitative case reports. On balance, the evidence suggests that Distributed Scrum has no impact, positive or negative, on overall project success. Consequently, claims by agile consultants who present Distributed Scrum as a recipe for project success should be treated with great caution, while researchers should investigate more varied perspectives to identify the real drivers of success in distributed and global software development.
Generalized Algebraic Phenomenological Model for Parallel-Plate Bipolar Electrochemical Reactors
Authors: Henquín E. R.
Published: October 2023

Electrochemical reactors with bipolar electrodes are widely used in industry and laboratories due to their ease of assembly and electrical connection. Understanding the impact of leakage currents on reactor performance is crucial for design improvement. Previous studies have analyzed these devices using the Laplace equation and Tafel kinetics for a single bipolar electrode. A simplified analysis of a reactor with multiple bipolar electrodes was also conducted, neglecting the contribution of intermediate electrodes to the leakage current. In this article, a simplified model to analyse the influence of leakage current on the electrode current distribution in a reactor with n bipolar electrodes is developed. Multiple models to study the current that flows perpendicular to the electrodes and finally becomes parasitic current, are studied. Also two reaction kinetics, Tafel and Butler-Volmer, are taking into account. Experimental data of reactors with one bipolar electrode considering Tafel-type kinetics, and with one and two bipolar electrodes considering primary current distribution, are compared with predictions obtained through the Laplace equation, and the models of this paper. Furthermore, given the current importance of green hydrogen, this work sheds light on the implications of the study and design of electrochemical reactors used in its production.
Insights into the Sodiation Kinetics of Si and Ge Anodes for Sodium-Ion Batteries
Authors: Zhang Jia , Zheng Tianye , Cheng Ka-wai Eric , Lam Kwok-ho , Boles Steven T.
Published: October 2023

Group IVA elements exhibit interesting Na storage capabilities due to the success of their Li alloy analogues. However, beyond hard carbon, they remain poorly understood as anodes for sodium-ion batteries (SIBs). Here, kinetic investigations of the electrochemical sodiation of Si and Ge are conducted using liquid electrolytes and half-cell configurations. Sodiation of Ge is found to be kinetically limited rather than thermodynamically limited. Either increasing temperature or decreasing sodiation rate can facilitate easier transformations from Ge to Na-Ge phases. A critical temperature seems to exist between 50 °C and 60 °C, beyond which a higher sodiation capacity is evident. The phase transformations are analyzed using Kolmogorov–Johnson–Mehl–Avrami theory. Following a one-dimensional growth, the Ge to NaGe4 is determined to be diffusion limited whereas NaGe4 to Na1+x
Ge is controlled by reaction speed. Moreover, the Arrhenius equation is employed to investigate the temperature dependence on both phase transformations, giving activation energies of ∼50 kJ·mol−1 and ∼70 kJ·mol−1, respectively. Schematic models are proposed to elucidate the sodiation mechanisms, potentially influencing sought-after advancements in cell formats and classifications. Not only does this work lay the foundation for efforts on the Ge-based anodes, but also provides analogous kinetic information to Si/Sn-based ones for SIBs.
Electrolytic Etching of Germanium Substrates with Hydrogen Peroxide
Authors: Wood Joseph G. , van Buuren Luke , Guo Ziang , Deniz Ece , S. Leite Marina , C. Carpenter Arthur , Hunt Charles E. , van Benthem Klaus
Published: October 2023

Anodic electrolytic etching of germanium has been performed in hydrogen peroxide etchants with controlled external conditions. In-situ current and ex-situ etch-depths were measured and tracked with respect to etchant composition and stir rates. Gas bubbles formed during the etching process were found to cause non-uniformity in etch-current and surface quality. The effects were minimized in specific composition spaces. Quantitative analysis revealed a linear correlation of the number of electrons transferred during germanium oxidation with the number of surface atoms removed. Experimental results of 2.77 electrons/atom deviate significantly from 4 electrons/atom previously reported for silicon. The conclusion is that etching mechanisms for germanium are sufficiently different from those for silicon which invalidates the direct transfer of processing techniques between the two materials.
Inhibition Effect and Mechanism of 2-Mercaptopyrimidine on Cobalt-Based Copper Interconnects Chemical Mechanical Polishing: Combined Experimental and DFT Study
Authors: Liu Jianghao , Niu Xinhuan , Zhan Ni , Zou Yida , Yan Han , Qu Minghui , Luo Fu , Shi Yunhui , Zhou Jianwei
Published: October 2023

Cobalt has been determined as a suitable barrier layer material for integrated circuits as the feature size continuous reduction to 14 nm. To protect the copper and cobalt surfaces from corrosion and obtain high copper and cobalt removal rate selectivity during cobalt-based copper interconnects chemical mechanical polishing process, selecting appropriate inhibitor in slurry is critical. In this paper, the inhibition effect and mechanism of 2-mercaptopyrimidine on copper/cobalt surfaces are studied combined experiments and density functional theory calculation. Experiments results reveal that 2-MP could increases the selectivity to 110.4, forms dense passivation film on the copper and cobalt surface to inhibits corrosion with high efficiency of 98% and 92%, and obtain ideal surface quality. Calculation results prove that the N-p and S-p orbitals of inhibitors hybridize with copper-d and cobalt-d orbital to form chemical bonds, adsorbing on metals surface vertically and parallelly. The mixed adsorption modes lead to form complete and dense passivation film. Such study provides better perspective into comprehending the corrosion protection of metal surfaces at the atomic level and clarifies the inhibition mechanism at the interface of metal-organic compounds.