bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonlinear Span Assessment by Amplitude-Dependent Linearization
Authors: Peek Ralf 
Published: May 2020

Abstract
Although it has long been recognized that vortex-induced vibrations of subsea pipeline spans involve nonlinear and inelastic behavior, the current practice to assess such spans for fatigue and ultimate loading conditions is based on the modal analysis assuming linear behavior. Nevertheless, nonlinearity can be captured approximately by making the linearization amplitude dependent. The eigenvalue problem to be solved for the natural frequencies and mode shapes then involves a stiffness matrix that depends on the mode shape and amplitude of vibration. An important part of the nonlinearity comes from the soil, which is generally represented by springs. This paper presents a simple and particularly effective algorithm to solve this nonlinear eigenvalue problem by using the same algorithm that serves to track the bifurcated solution branches in quasi-static structural stability (buckling) analyses. This method is applied to an example in which the nonlinearity comes from the soil springs. The results demonstrate the importance of the nonlinearity, even at relatively low vortex-induced vibrations (VIV) amplitudes typical of the pure inline response. The inelasticity of the soil springs is also used to calculate the associated contribution to the modal damping ratio.
Gravity Wave Trapping by Series of Horizontally Stratified Wave Absorbers Away From Seawall
Authors: Venkateswarlu V. , Karmakar D. 
Published: May 2020

AbstractThe fluid oscillation between the rigid wall and stratified wave absorber is analyzed in the context of the linearized water wave theory. The stratified wave absorber is composed of multiple horizontal layers considering higher porosity in the surface layer, moderate porosity in the middle layer, and zero porosity in the bottom layer. The study examined the wave motion through multiple horizontally stratified wave absorbers on solving the multilayer dispersion relation. The eigenfunction expansion method is used to form the system of analytical equations using the property of orthogonal mode-coupling relation with continuity of dynamic pressure and velocity at each of the interfaces. The free spacing available between leeward porous wave absorber and the rigid wall is termed as “trapping chamber.” The effect of the trapping chamber on wave reflection and fluid force experienced by a rigid wall is discussed. The analytical results formulated for the physical problem are validated with the available experimental and numerical results. The wave trapping is examined and compared for three types of seawalls such as vertical wall, permeable wall, and stepped wall. The change in trapping chamber length shows the harmonic peaks and troughs in the trapping coefficients and the harmonic oscillations help in the design and development of the stratified porous wave absorbers for the protection of marine infrastructure.
Study on Logarithmic Crowning of Tapered Roller Profile Considering Angular Misalignment
Authors: Wu Zhenghai , Xu Yingqiang , Liu Kaian 
Published: May 2020

Abstract
The angular misalignment of the tapered roller contact pair aggravates the stress edge effect and the stress concentration effect at the contact field, which in turn would affect bearing capacity and fatigue life of the contact pair. In this paper, based on the angular misalignment, the geometric interference model of the tapered roller contact pair was established. And two types of logarithmic crowning models for the roller profile design were theoretically deduced, in which design redundancy was considered through the quadratic processing of the pre-pressure. Then, with the discrete convolution and fast Fourier transform (DC-FFT) method and the conjugate gradient method (CGM), contact characteristics of the tapered roller with these two logarithmic profiles were verified. The results show that two profiles can effectively prevent the stress edge/concentration effect, improve contact pressure distribution and stress field of the roller in misalignment state, and ensure that the contact condition in alignment state is not greatly affected. The logarithmic crowning scheme is also suitable for the profile design of heavy-duty tapered rollers and can provide a reference for the crowning of other finite-line contact pairs under angular misalignment.
Experimental Analysis of a Particle Separator Design With Full-Field Three-Dimensional Measurements
Authors: Borup Daniel D. , Elkins Christopher J. , Eaton John K. 
Published: May 2020

Abstract
Particle ingestion into turbine engines can cause significant damage through deposition in internal cooling passages. Musgrove et al. proposed a compact particle separator installed between the combustor bypass exit and turbine vane cooling passage inlet. The design had small pressure losses but provided limited particle separation. Its performance has proved difficult to replicate. Borup et al. recently developed a magnetic resonance imaging (MRI)-based technique for full-field, 3D measurements of the mean particle concentration distribution in complex flows. A particle separator based on the Musgrove et al. design was fabricated out of plastic using 3D printing, with the addition of a drain from the collector through which 3% of the total flow was extracted. The separator efficiency was measured at two Reynolds numbers, using water as the working fluid and 33-μm titanium microspheres to represent dust particles. Stokes number was shown to play the dominant role in determining efficiency across studies. MRI was used to obtain the 3D particle volume fraction and three-component velocity fields. The velocity data showed that flow was poorly distributed between the separator louvers, while the collector flow followed the optimal pattern for particle retention. The MRI data revealed that strong swirling flow in the collector centrifuged particles toward the outer wall of the collector and into a partitioned region of quiescent flow, where they proceeded to exit the collector. Future designs could be improved by re-arranging the louvers to produce a more uniform flow distribution, while maintaining the effective collector design.
“What’s Worth Doing?”: A Qualitative Historical Analysis of the TPSR Model
Authors: Richards K. Andrew R. , Shiver Victoria N. 
Published: May 2020

Purpose: The authors sought to trace the development of the teaching personal and social responsibility (TPSR) model from its initial conception by Don Hellison as a humanistic approach to teaching physical education to the current version of the model through qualitative historiography.Methods: Data sources included: (a) books written by Don, (b) sources that discussed the evolution of the model, and (c) supplemental texts that are important to the TPSR literature.Results: The authors identified four phases of TPSR model development: (a) setting the stage for a humanistic approach through practical inquiry, (b) moving beyond balls and bats to developing a model focused on the affective domain, (c) further defining humanistic goals and teaching strategies, and (d) continuous tinkering in the context of a living model.Discussion/Conclusions: Lessons learned about the model are discussed in relation to practical inquiry, and recommendations are made related to the future of the TPSR model.
Diagnostic accuracy of diabetic retinopathy grading by an artificial intelligence-enabled algorithm compared with a human standard for wide-field true-colour confocal scanning and standard digital retinal images
Authors: Olvera-Barrios Abraham , Heeren Tjebo FC , Balaskas Konstantinos , Chambers Ryan , Bolter Louis , Egan Catherine , Tufail Adnan , Anderson John 
Published: May 2020

BackgroundPhotographic diabetic retinopathy screening requires labour-intensive grading of retinal images by humans. Automated retinal image analysis software (ARIAS) could provide an alternative to human grading. We compare the performance of an ARIAS using true-colour, wide-field confocal scanning images and standard fundus images in the English National Diabetic Eye Screening Programme (NDESP) against human grading.MethodsCross-sectional study with consecutive recruitment of patients attending annual diabetic eye screening. Imaging with mydriasis was performed (two-field protocol) with the EIDON platform (CenterVue, Padua, Italy) and standard NDESP cameras. Human grading was carried out according to NDESP protocol. Images were processed by EyeArt V.2.1.0 (Eyenuk Inc, Woodland Hills, California). The reference standard for analysis was the human grade of standard NDESP images.ResultsWe included 1257 patients. Sensitivity estimates for retinopathy grades were: EIDON images; 92.27% (95% CI: 88.43% to 94.69%) for any retinopathy, 99% (95% CI: 95.35% to 100%) for vision-threatening retinopathy and 100% (95% CI: 61% to 100%) for proliferative retinopathy. For NDESP images: 92.26% (95% CI: 88.37% to 94.69%) for any retinopathy, 100% (95% CI: 99.53% to 100%) for vision-threatening retinopathy and 100% (95% CI: 61% to 100%) for proliferative retinopathy. One case of vision-threatening retinopathy (R1M1) was missed by the EyeArt when analysing the EIDON images, but identified by the human graders. The EyeArt identified all cases of vision-threatening retinopathy in the standard images.ConclusionEyeArt identified diabetic retinopathy in EIDON images with similar sensitivity to standard images in a large-scale screening programme, exceeding the sensitivity threshold recommended for a screening test. Further work to optimise the identification of ‘no retinopathy’ and to understand the differential lesion detection in the two imaging systems would enhance the use of these two innovative technologies in a diabetic retinopathy screening setting.
Henle fibre layer haemorrhage: clinical features and pathogenesis
Authors: Baumal Caroline R , Sarraf David , Bryant Tara , Gui Wei , Muakkassa Nora , Pichi Francesco , Querques Giuseppe , Choudhry Netan , Teke Mehmet Yasin , Govetto Andrea , Invernizzi Alessandro , Eliott Dean , Gaudric Alain , Cunha de Souza Eduardo , Naysan Jonathan , Lembo Andrea , Lee Grace C , Freund K Bailey 
Published: May 2020

BackgroundTo describe the clinical presentation and characteristic imaging features of deep retinal haemorrhages primarily located in the Henle fibre layer (HFL) of the macula. The spectrum of aetiologies and a comprehensive theory of pathogenesis are presented.MethodsThis is a retrospective, multicentre case series evaluating eyes with retinal haemorrhage in HFL. Clinical features, underlying aetiology, systemic and ocular risk factors, visual acuity, and multimodal imaging including fundus photography and cross-sectional and en face optical coherence tomography (OCT) are presented.ResultsRetinal haemorrhages localised to HFL in 33 eyes from 23 patients were secondary to acute blunt trauma to the head (n=2), eye (n=1) and trunk (n=1), ruptured intracranial aneurysm (Terson’s syndrome, n=3), general anaesthesia (n=1), epidural anaesthesia (n=1), hypertension with anaemia (n=1), decompression retinopathy (n=1), postvitrectomy with intraocular gas (n=1), retinal vein occlusion (n=7), myopic degeneration (n=2), macular telangiectasia type 2 (n=1), and polypoidal choroidal vasculopathy (n=1). Defining clinical features included deep retinal haemorrhage with feathery margin and petaloid pattern radiating from the fovea. OCT demonstrated characteristic hyper-reflectivity from the haemorrhage delineated by obliquely oriented fibres in the Henle layer. Spontaneous resolution of HFL haemorrhage occurred after 3 months in 15 patients with follow-up.ConclusionThe characteristic petaloid-shaped, deep intraretinal haemorrhage with a feathery margin localised to HFL is associated with various disorders. The terminology ‘Henle fiber layer hemorrhage (HH)’ is proposed to describe the clinical and OCT findings, which may result from abnormal retinal venous pressure from systemic or local retinovascular disorders affecting the deep capillary plexus or from choroidal vascular abnormalities.
Improving function in people with hip-related pain: a systematic review and meta-analysis of physiotherapist-led interventions for hip-related pain
Authors: Kemp Joanne L , Mosler Andrea B , Hart Harvi , Bizzini Mario , Chang Steven , Scholes Mark J , Semciw Adam I , Crossley Kay M 
Published: May 2020

ObjectiveTo report the effectiveness of physiotherapist-led interventions in improving pain and function in young and middle-aged adults with hip-related pain.DesignSystematic review and meta-analysis.Data sourcesA comprehensive, reproducible search strategy was performed on five databases in May 2019. Reference lists and grey literature were also searched.Eligibility criteria for selecting studiesPopulation: people aged ≥18 years with hip-related pain (with or without a diagnosis of femoroacetabular impingement syndrome). Intervention(s): physiotherapist-led interventions for hip pain. Comparators: sham treatment, no treatment or other treatment (eg, hip arthroscopic surgery). Outcomes: primary outcomes included patient-reported hip pain and function. Secondary outcomes included physical function measures.Results1722 papers were identified. After exclusion criteria were applied, 14 studies were included for analysis. They had varied risk of bias. There were no full-scale placebo-controlled randomised controlled trials (RCTs) of physiotherapist-led treatment. Pooled effects ranged from moderate effects (0.67 (95% CI 0.07 to 1.26)) favouring physiotherapist-led intervention over no treatment post-arthroscopy, to weak effects (−0.32 (95% CI 0.57 to 0.07)) favouring hip arthroscopy over physiotherapist-led treatment.ConclusionPhysiotherapist-led interventions might improve pain and function in young and middle-aged adults with hip-related pain, however full-scale high-quality RCT studies are required.PROSPERO registration numberCRD42018089088.
Prevalence of therapeutic use exemptions at the Olympic Games and association with medals: an analysis of data from 2010 to 2018
Authors: Vernec Alan , Healy David 
Published: May 2020

ObjectivesThe percentage of athletes with Therapeutic Use Exemptions (TUEs) competing in elite sport and the association with winning medals has been a matter of speculation in the absence of validated competitor numbers. We used International Olympic Committee (IOC) and World Anti-Doping Agency (WADA) data to identify athletes competing with TUEs at five Olympic Games (Games) and a possible association between having a TUE and winning an Olympic medal.MethodsWe used the IOC’s competition results and WADA’s TUE database to identify the number of TUEs for athlete competitions (ACs, defined as one athlete competing in one event) and any associations with medals among athletes competing in individual competitions. We calculated risk ratios (RR) for the probability of winning a medal among athletes with a TUE compared with that of athletes without a TUE. We also reported adjusted RR (RRadj) controlling for country resources, which is a potential confounder.ResultsDuring the Games from 2010 to 2018, there were 20 139 ACs and 2062 medals awarded. Athletes competed with a TUE in 0.9% (181/20 139) of ACs. There were 21/2062 medals won by athletes with a TUE. The RR for winning a medal with a TUE was 1.13 (95% CI: 0.73 to 1.65; p=0.54), and the RRadjwas 1.07 (95% CI: 0.69 to 1.56; p=0.73).ConclusionThe number of athletes competing with valid TUEs at Games is <1%. Our results suggested that there is no meaningful association between being granted a TUE and the likelihood of winning a medal.
Contributions of amino acid, acylcarnitine and sphingolipid profiles to type 2 diabetes risk among South-Asian Surinamese and Dutch adults
Authors: Muilwijk Mirthe , Goorden Susan M I , Celis-Morales Carlos , Hof Michel H , Ghauharali-van der Vlugt Karen , Beers-Stet Femke S , Gill Jason M R , Vaz Frédéric M , van Valkengoed Irene G M 
Published: May 2020

IntroductionPeople of South Asian origin are at high risk of type 2 diabetes (T2D), but the underpinning mechanisms are not fully understood. We determined ethnic differences in acylcarnitine, amino acid and sphingolipid concentrations and determined the associations with T2D.Research design and methodsAssociations between these metabolites and incident T2D among Dutch and South-Asian Surinamese were determined in participants from the Healthy Life in an Urban Setting (HELIUS) study (Amsterdam, the Netherlands) using Prentice-weighted Cox regression. The HELIUS study includes 95 incident T2D cases and a representative subcohort of 700 people from a cohort of 5977 participants with a mean follow-up of 4 years.ResultsConcentrations of acylcarnitines were comparable between both ethnic groups. Amino acid and lactosylceramide concentrations were higher among South-Asian Surinamese than Dutch (eg, isoleucine 65.7 (SD 16.3) vs 60.7 (SD 15.6) µmol/L). Ceramide concentrations were lower among South-Asian Surinamese than Dutch (eg, Cer d18:1 8.48 (SD 2.04) vs 9.08 (SD 2.29) µmol/L). Metabolic dysregulation preceded T2D without evidence for a multiplicative interaction by ethnicity. Most amino acids and (dihydro)ceramides were associated with increased risk (eg, Cer d18:1 HR 2.38, 95% CI 1.81 to 3.12) while acylcarnitines, glycine, glutamine and lactosylceramides were associated with decreased risk for T2D (eg, LacCer d18:2 HR 0.56, 95% CI 0.42 to 0.77).ConclusionsOverall, these data suggest that the disturbances underlying amino acid and sphingolipid metabolism may be predictive of T2D risk in populations of both South Asian and European background. These observations may be used as starting point to unravel the underlying metabolic disturbances.
Patients’ perspectives of facilitators and barriers to patient-centred care: insights from qualitative patient interviews
Authors: Vennedey Vera , Hower Kira Isabel , Hillen Hendrik , Ansmann Lena , Kuntz Ludwig , Stock Stephanie 
Published: May 2020

ObjectivesPrevious studies on patient-centred care (PCC) and its facilitators and barriers usually considered specific patient groups, healthcare settings and aspects of PCC or focused on expert perspectives. The objective of this study was to analyse patients’ perspectives of facilitators and barriers towards implementing PCC.DesignWe conducted semistructured individual interviews with chronically ill patients. The interviewees were encouraged to share positive and negative experiences of care and the related facilitators and barriers in all settings including preventive, acute and chronic health issues. Interview data were analysed based on the concept of content analysis.SettingInterviews took place at the University Hospital Cologne, nursing homes, at participants’ homes or by telephone.ParticipantsAny person with at least one chronic illness living in the region of Cologne was eligible for participation. 25 persons with an average age of 60 years participated in the interviews. The participants suffered from various chronic conditions including mental health problems, oncological, metabolic, neurological diseases, but also shared experiences related to acute health issues.ResultsParticipants described facilitators and barriers of PCC on the microlevel (eg, patient–provider interaction), mesolevel (eg, health and social care organisation, HSCO) and macrolevel (eg, laws, financing). In addition to previous concepts, interviewees illustrated the importance of being an active patient by taking individual responsibility for health. Interviewees considered functioning teams and healthy staff members a facilitator of PCC as this can compensate stressful situations or lack of staff to some degree. A lack of transparency in financing and reimbursement was identified as barrier to PCC.ConclusionIndividual providers and HSCOs can address many facilitators and barriers of PCC as perceived by patients. Large-scale changes such as reduction of administrative barriers, the expansion of care networks or higher mandatory nurse to patient ratios require political action and incentives.Trial registration numberDRKS00011925
Risk factors for recurrent falls in older adults: a study protocol for a systematic review with meta-analysis
Authors: Jehu Deborah A , Davis Jennifer C , Liu-Ambrose Teresa 
Published: May 2020

IntroductionOlder adults who fall recurrently (i.e., >1 fall/year) are at risk for functional decline and mortality. Key risk factors for recurrent falls in community-dwelling older adults are not well established due to methodological limitations, such as recall bias. A better understanding of the risk factors for recurrent falls will aid in refining clinical practice guidelines for secondary fall prevention strategies. The primary objective of this systematic review with meta-analysis is to examine the risk factors for recurrent falls in prospective studies among community-dwelling older adults.Methods and analysisA comprehensive search for articles indexed in MEDLINE, EMBASE, PsycINFO and CINAHL databases as well as grey literature was conducted on April 25, 2019. We will use MeSH and keyword search terms around the following topics: falls, recurrence, fall-risk, ageing and prospective studies. Prospective studies with monthly falls monitoring for 12 months, investigating risk factors for recurrent falls in older adults will be included. One author will complete the search. Two authors will remove duplicates and screen the titles and abstracts for their potential inclusion against the eligibility criteria. Two authors will screen the full texts and extract the data using a piloted extraction sheet. Included studies will be evaluated for the risk of bias with the Joanna Briggs Institute Prevalence Critical Appraisal tools. The quality of reporting will be determined with the Strengthening the Reporting of OBservational studies in Epidemiology. The data extraction will include study characteristics as well as sociodemographic, balance and mobility, sensory and neuromuscular, psychological, medical, medication and environmental factors. The results will be presented via figures, summary tables, meta-analysis (when possible) and narrative summaries.Ethics and disseminationNo ethics approval will be required. Findings will be disseminated through publication and media.PROSPERO registration numberCRD42019118888; Pre-results.