bluuebunny/crossref_metadata_2025 huggingface dataset:
A randomised controlled trial comparing femtosecond laser-assisted cataract
surgery versus conventional phacoemulsification surgery: 12-month results
Authors: Stanojcic Nick , Roberts Harry William , Wagh Vijay K , Li Ji-Peng Olivia , Naderi Khayam , O’Brart David P
Published: July 2020

Aims

To report 12-month outcomes of randomised controlled trial comparing
conventional phacoemulsification surgery (CPS) with femtosecond laser-assisted
cataract surgery (FLACS).

Methods

This was a single-centre, prospective single-masked randomised
case-controlled trial. Four hundred patients were randomised to CPS or FLACS
with the LenSx platform (Alcon Laboratories Inc.). Visual acuity, refraction,
central corneal thickness, endothelial cell loss (ECL), adverse events and
quality of life outcomes, using EuroQOL 5-dimensions (EQ-5D-3 L) and cataract
surgery patient-reported outcome measures (PROMs) questionnaires (Cat-PROM5),
were recorded.

Results

Two hundred and thirty four patients (58.5%) attended 12-month follow-up
(116 FLACS, 118 CPS). Mean LogMAR unaided distance visual acuity) (±SD) was
0.12 (0.18) with FLACS and 0.13 (0.19) with CPS (p=0.68; 95% Confidence
Interval [CI]−0.06,0.04). Mean spherical equivalent (SE) refraction was
−0.1±0.6 diopters (D) with FLACS and −0.2±0.6 D with CPS (p=0.44; 95% CI −0.09,
0.21). Mean corrected distance visual acuity (±SD) was −0.01 (0.1) with FLACS
and 0(0.1) with CPS (p=0.45; 95% CI −0.04,0.02). Two patients per group
underwent YAG laser capsulotomy for posterior capsular opacification (p=1).
Mean ECL (per mm2±SD) was 301±320 with FLACS and 228±303
with CPS (p=0.07; 95% CI −7.26, 153.26). Mean Cat-PROM scores (±SD) were −5.5
(2.6) with FLACS and −5.8 (2.5) with CPS (p=0.3; 95% CI 0.31,1.01). EQ5-3DL
mean index score (±SD) was 0.92 (0.13) with FLACS and 0.89 (0.14) with CPS
(p=0.1; 95% CI −0.1, 0.01). Vector analysis comparing manual limbal relaxing
incisions (LRIs) and intrastromal femtosecond laser-assisted astigmatic
keratotomies (iFAKs) showed a greater correction index (p=0.02; 95% CI 0.06 to
0.60) and smaller difference vector (p=0.046; 95% CI −0.54, −0.01) with
iFAK.

Conclusions

There were no differences in vision, refraction, adverse postoperative
events or PROMs between FLACS and CPS groups at 12 months. iFAKs may provide
more effective astigmatic correction compared to LRIs, 12 months
postoperatively.
Are questionable research practices facilitating new discoveries in sport and exercise medicine? The proportion of supported hypotheses is implausibly high
Authors: Büttner Fionn , Toomey Elaine , McClean Shane , Roe Mark , Delahunt Eamonn
Published: July 2020

Questionable research practices (QRPs) are intentional and unintentional practices that can occur when designing, conducting, analysing, and reporting research, producing biased study results. Sport and exercise medicine (SEM) research is vulnerable to the same QRPs that pervade the biomedical and psychological sciences, producing false-positive results and inflated effect sizes. Approximately 90% of biomedical research reports supported study hypotheses, provoking suspicion about the field-wide presence of systematic biases to facilitate study findings that confirm researchers’ expectations. In this education review, we introduce three common QRPs (ie,HARKing,P-hackingandCherry-picking), perform a cross-sectional study to assess the proportion of original SEM research that reports supported study hypotheses, and draw attention to existing solutions and resources to overcome QRPs that manifest in exploratory research. We hypothesised that ≥ 85% of original SEM research studies would report supported study hypotheses. Two independent assessors systematically identified, screened, included, and extracted study data from original research articles published between 1 January 2019 and 31 May 2019 in theBritish Journal of Sports Medicine, Sports Medicine,theAmerican Journal of Sports Medicine,and theJournal of Orthopaedic & Sports Physical Therapy. We extracted data relating to whether studies reported that the primary hypothesis was supported or rejected by the results. Study hypotheses, methodologies, and analysis plans were preregistered at the Open Science Framework. One hundred and twenty-nine original research studies reported at least one study hypothesis, of which 106 (82.2%) reported hypotheses that were supported by study results. Of 106 studies reporting that primary hypotheses were supported by study results, 75 (70.8%) studies reported that the primary hypothesis was fully supported by study results. The primary study hypothesis was partially supported by study results in 28 (26.4%) studies. We detail open science practices and resources that aim to safe-guard against QRPs that bely the credibility and replicability of original research findings.
Association between brachial-ankle pulse wave velocity and risk of type 2 diabetes mellitus: results from a cohort study
Authors: Lou Yan-mei , Liao Min-qi , Wang Chang-yi , Chen Hong-en , Peng Xiao-lin , Zhao Dan , Gao Xu-ping , Xu Shan , Wang Li , Ma Jian-ping , Ping Zhao , Zeng Fang-fang
Published: July 2020

Introduction

Brachial-ankle pulse wave velocity (ba-PWV), as a simple and easily measured marker of arterial stiffness, has not been prospectively explored for its role in type 2 diabetes mellitus (T2DM) risk among the general population. This study aimed to explore the association between baseline ba-PWV value and new-onset T2DM among Chinese adults.

Research design and methods

Using data from Xiaotangshan Hospital, we conducted a prospective cohort study among those who underwent annual or biennial health check-up examinations and who had their ba-PWV measured from 2009 to 2016. We explored the risk of new-onset T2DM across ba-PWV tertiles using Cox proportional-hazards regression analysis.

Results

Of 6122 adults (68.9% male; mean age: 51.0 (SD 13.0) years) without T2DM and with ba-PWV measured at baseline, 599 participants developed T2DM during an average of 3.8 (SD 2.3) years of follow-up. After multivariable adjustment, ba-PWV was positively related to T2DM risk (p for trend=0.008). Compared with the lowest ba-PWV tertile, the HRs and their 95% CIs were 1.57 (1.18 to 2.10) for the second and 1.66 (1.24 to 2.22) for the third tertile. The risk across ba-PWV tertiles increased steadily from 1000 cm/s to 1400 cm/s and then reached a plateau. Subgroup analyses indicated a significantly higher risk among those aged <65 years and current smokers (p for interactions: <0.001 and 0.006).

Conclusions

Our findings suggest that ba-PWV might be a useful and independent predictor of new-onset T2DM with ba-PWV ranging between 1000 cm/s and 1400 cm/s, especially among younger individuals and current smokers.
Drinking in denial: a cross-sectional analysis of national survey data in Ireland to measure drinkers’ awareness of their alcohol use
Authors: Mongan Deirdre , Millar Sean R , O'Dwyer Claire , Long Jean , Galvin Brian
Published: July 2020

Objectives

Ireland has high per capita alcohol consumption and also has high levels of problematic drinking patterns. While it is accepted that patterns of alcohol consumption in Ireland are a cause for concern, it is not clear if Irish people are actually aware of the extent of their hazardous or harmful pattern of drinking. The aim of this study was to determine awareness of drinking pattern in an Irish population using a representative random sample and to identify characteristics associated with self-awareness of hazardous or harmful drinking.

Methods

We analysed data from Ireland’s 2014/2015 Drug Prevalence Survey which recruited a stratified clustered sample of 7005 individuals aged 15 years and over living in private households. Logistic regression analysis was used to determine characteristics associated with self-awareness of hazardous or harmful drinking.

Results

Almost one half of drinkers had a hazardous or harmful pattern of drinking; 38% engaged in monthly risky single occasion drinking (RSOD) and 10.5% met Diagnostic and Statistical Manual version IV (DSM-IV) criteria for alcohol dependence. Of the 2420 respondents who had a hazardous or harmful pattern of drinking, 67% were unaware of this and misclassified themselves as being either a light or moderate drinker who did not engage in RSOD. An adjusted logistic regression model identified that hazardous and harmful drinkers were more likely to be aware of their drinking pattern if they had completed third level education (OR=1.80, 95% CI: 1.30 to 2.49) while older drinkers (aged 65 and over) were less likely to be aware of their drinking pattern (OR=0.30, 95% CI: 0.14 to 0.65). Subjects who engaged in risk taking behaviours such as illicit drug use and gambling were also significantly more likely to be aware of their drinking pattern.

Conclusions

The results of this study suggest that patterns of alcohol use in Ireland are problematic. Older respondents and those with lower educational attainment are less likely to be aware of their hazardous or harmful drinking pattern. There is also a population of younger, more-educated drinkers who engage in potentially risk-taking behaviours and these subjects are aware of their harmful drinking pattern. Initiatives to reduce overall alcohol consumption and raise awareness around drinking patterns are required.
Early Parenting Intervention – Biobehavioral Outcomes in infants with Neurodevelopmental Disabilities (EPI-BOND): study protocol for an Italian multicentre randomised controlled trial
Authors: Montirosso Rosario , Rosa Elisa , Giorda Roberto , Fazzi Elisa , Orcesi Simona , Cavallini Anna , Provenzi Livio
Published: July 2020

Introduction

Neurodevelopmental disability (ND) represents an adverse condition for infants’ socio-emotional and behavioural development as well as for caregiving (eg, parental sensitivity) and mother-infant interaction. Adverse exposures are associated with altered neuroendocrine hormones concentrations (eg, oxytocin and cortisol) and epigenetic regulation (eg, methylation of stress-related genes), which in turn may contribute to less-than-optimal mother-infant interaction. Parental sensitivity is a protective factor for childrens’ development and early parental interventions (eg, video-feedback intervention) can promote parental caregiving and better developmental outcomes in children. The present multi-centric and longitudinal randomised controlled trial aims to assess if and to which extent early VFI could benefit both infants and mothers in terms of behavioural outcomes as well as neuroendocrine and epigenetic regulation.

Methods and analysis

Dyads will be randomly assigned to the video-feedback Intervention Group or Control Group (‘dummy’ intervention: telephone calls). Infants with ND aged 3 to 18 months will be recruited from three major child neuropsychiatric units in northern Italy. A multi-layer approach to intervention effects will include videotapes of mother-infant interaction, maternal reports as well as saliva samples for hormones concentrations and target-gene methylation analysis (eg, BDNF, NR3C1, OXTR and SCL6A4) that will be obtained at each of the four assessment sessions: T0, baseline; T1, post-intervention; T2, short-term follow-up (3 month); T3, long-term follow-up (6 month). Primary effectiveness measures will be infant socio-emotional behaviour and maternal sensitivity. Neuroendocrine hormones concentrations and DNA methylation status of target genes will be secondary outcomes. Feasibility, moderation and confounding variables will be measured and controlled between the two groups.

Ethics and dissemination

Ethics approval has been obtained in all three participating units. Results of the main trial and each of the secondary endpoints will be submitted for publication in peer-reviewed journals and international conferences.

Trial registration number

NCT03853564; Pre-results.
Digital pathology in the time of corona
Authors: Stathonikos Nikolas , van Varsseveld Nadege C , Vink Aryan , van Dijk Marijke R , Nguyen Tri Q , Leng Wendy W J de , Lacle Miangela M , Goldschmeding Roel , Vreuls Celien P H , van Diest Paul J
Published: July 2020

The 2020 COVID-19 crisis has had and will have many implications for healthcare, including pathology. Rising number of infections create staffing shortages and other hospital departments might require pathology employees to fill more urgent positions. Furthermore, lockdown measures and social distancing cause many people to work from home. During this crisis, it became clearer than ever what an asset digital diagnostics is to keep pathologists, residents, molecular biologists and pathology assistants engaged in the diagnostic process, allowing social distancing and a ‘need to be there’ on-the-premises policy, while working effectively from home. This paper provides an overview of our way of working during the 2020 COVID-19 crisis with emphasis on the virtues of digital pathology.
Identification of late asthmatic reactions following specific inhalation challenge
Authors: Moore Vicky C , Walters Gareth Iestyn , Robertson Alastair S , Burge P Sherwood
Published: July 2020

Specific inhalation challenge (SIC) is the reference standard for the diagnosis of occupational asthma. Current guidelines for identifying late asthmatic reactions are not evidence based.

Objectives

To identify the fall in forced expiratory volume in 1 s (FEV1) required following SIC to exceed the 95% CI for control days, factors which influence this and to show how this can be applied in routine practice using a statistical method based on the pooled SD for FEV1from three control days.

Methods

Fifty consecutive workers being investigated for occupational asthma were asked to self-record FEV1hourly for 2 days before admission for SIC. These 2 days were added to the in-hospital control day to calculate the pooled SD and 95% CI.

Results

45/50 kept adequate measurements. The pooled 95% CI was 385 mL (SD 126), or 14.2% (SD 6.2) of the baseline FEV1, but was unrelated to the baseline FEV1(r=0.06, p=0.68), or gender, atopy, smoking, non-specific reactivity or treatment before or during SIC. Thirteen workers had a late asthmatic reaction with ≥2 consecutive FEV1measurements below the 95% CI for pooled control days, 4/13 had <15% and 9/13 >15% late fall from baseline. The four workers with ≥2 values below the 95% CI all had independent evidence of occupational asthma.

Conclusion

The pooled SD method for defining late asthmatic reactions has scientific validity, accounts for interpatient spirometric variability and diurnal variation and can identify clinically relevant late asthmatic reactions from smaller exposures. For baseline FEV1<2.5 L, a 15% fall is within the 95% CI.
Fermentation of barley and wheat with lactic acid bacteria and exogenous enzyme on nutrient composition, microbial count, and fermentative characteristics
Authors: Agyekum A.K. , Beaulieu A.D. , Pieper R. , Van Kessel A.G.
Published: July 2020

Characteristics of wheat and barley inoculated with a homo-fermentative (HO) or hetero-fermentative (HE) lactic acid bacteria (LAB) were investigated in separate 97 d studies conducted using a 3 × 2 factorial arrangement comparing inoculants (no inoculant, HO or HE) and multi-enzyme (no or yes) addition. The pH declined (P < 0.05) to below 4.5 by day 6, coinciding with peaks in lactobacilli and yeast counts. A more rapid decline (P < 0.05) in pH and lactobacilli count but higher (P < 0.05) yeast count was observed with HO relative to HE. Enzyme addition reduced pH in inoculated grains only, particularly with HE (inoculant × enzyme effect; P < 0.05). Higher dry matter losses (P < 0.05) were observed with HE, most apparent in barley. Lactate was generally highest in HO and was increased by enzyme addition. Acetate was higher (P < 0.05) in HE. Ethanol and ammonia were lowest (P < 0.05) in HO. Wheat neutral detergent fibre (NDF) was reduced by both inoculants compared with control, whereas enzyme addition reduced NDF content in both grains. In conclusion, although not marked, fermentation responses appeared greater in wheat than barley although either LAB inoculant improved grain fermentation characteristics. The multi-enzyme appeared active during fermentation.
Effects of dietary red-osier dogwood (Cornus stolonifera) on growth performance, blood profile, ileal morphology, and oxidative status in weaned pigs challenged with Escherichia coli K88+
Authors: Koo Bonjin , Amarakoon Sirini Budhika , Jayaraman Balachandar , Siow Yaw L. , Prashar Suvira , Shang Yue , Karmin O. , Nyachoti Charles Martin
Published: July 2020

A total of 28 piglets weaned at 21 d of age (6.94 ± 0.28 kg of body weight) were assigned to one of four dietary treatments for 14 d: (1) negative control (NC; a corn–wheat–soybean meal diet), (2) positive control [PC; NC + 0.025% antimicrobial growth promoter (AGP)], (3) ROD2 [2% red-osier dogwood (ROD)], and (4) ROD4 (4% ROD). All pigs were orally inoculated with Escherichia coli K88+ on day 8. The pre-planned orthogonal test was performed to compare (1) NC vs. PC and (2) NC vs. ROD. The inclusion of ROD in a nursery diet increased (P < 0.05) superoxide dismutase (SOD) activities and decreased (P < 0.05) malondialdehyde (MDA) concentrations in the serum. Moreover, pigs fed with ROD diets had shallower (P < 0.05) crypt depth and higher (P < 0.05) villus height to crypt depth ratio than those fed the NC diet. Dietary AGP supplementation reduced (P < 0.05) the MDA concentration in the ileum and serum at 24 h after challenge, and improved (P < 0.01) the SOD activities in the serum. In conclusion, the inclusion of ROD in a nursery diet enhanced the antioxidative defense system and intestinal morphology, showing comparable effects with AGP supplementation.
Scattering of massless scalar field by charged dilatonic black holes
Authors: Huang Yang , Zhang Hongsheng
Published: July 2020

Wave propagations in the presence of black holes is a significant problem both in theoretical and observational aspects, especially after the discovery of gravitational wave and confirmation of black holes. We study the scattering of massless scalar field by a charged dilatonic black hole in frame of full wave theory. We apply partial wave method to obtain the scattering cross sections of the scalar field, and investigate how the black hole charge affects the scalar scattering cross sections. Furthermore, we investigate the Regge pole approach of the scattering cross section of the dilatonic black hole. We find that in order to obtain results at the same precision, we need more Regge poles as the black hole charge increases. We compare the results in the full wave theory and results in the classical geodesic scattering and the semi-classical glory approximations, and demonstrate the improvements and power of our approach.
Comparison of optical potential for nucleons and $$\varDelta $$ resonances
Authors: Bodek Arie , Cai Tejin
Published: July 2020

Precise modeling of neutrino interactions on nuclear targets is essential for neutrino oscillations experiments. The modeling of the energy of final state particles in quasielastic (QE) scattering and resonance production on bound nucleons requires knowledge of both the removal energy of the initial state bound nucleon as well as the average Coulomb and nuclear optical potentials for final state leptons and hadrons. We extract the average values of the real part of the nuclear optical potential for final state nucleons ($$U_{opt}^{QE}$$UoptQE) as a function of the nucleon kinetic energy from inclusive electron scattering data on nuclear targets ($$_\mathbf{6 }^\mathbf{12 }{} \mathbf{C} $$612C+$$_\mathbf{8 }^\mathbf{16 }{} \mathbf{O} $$816O, $$_\mathbf{20 }^\mathbf{40 }{} \mathbf{Ca} $$2040Ca+$$_\mathbf{18 }^\mathbf{40 }{} \mathbf{Ar} $$1840Ar, $$_\mathbf{3 }^\mathbf{6 }{} \mathbf{Li} $$36Li, $$_\mathbf{18 }^\mathbf{27 }{} \mathbf{Al} $$1827Al, $$_\mathbf{26 }^\mathbf{56 }{} \mathbf{Fe} $$2656Fe, $$_\mathbf{82 }^\mathbf{208 }{} \mathbf{Pb} $$82208Pb) in the QE region and compare to calculations. We also extract values of the average of the real part of the nuclear optical potential for a $$\varDelta (1232)$$Δ(1232) resonance in the final state ($$U^\varDelta _{opt}$$UoptΔ) within the impulse approximation. We find that $$U^\varDelta _{opt}$$UoptΔ is more negative than $$U_{opt}^{QE}$$UoptQE with $$U^\varDelta _{opt}\approx $$UoptΔ≈1.5 $$U_{opt}^{QE}$$UoptQE for $$_\mathbf{6 }^\mathbf{12 }{} \mathbf{C} $$612C.
Noether symmetry approach to the non-minimally coupled $$Y(R)F^2$$ gravity
Authors: Sert Özcan , Çeliktaş Fatma
Published: July 2020

We use Noether symmetry approach to find spherically symmetric static solutions of the non-minimally coupled electromagnetic fields to gravity. We construct the point-like Lagrangian under the spherical symmetry assumption. Then we determine Noether symmetry and the corresponding conserved charge. We derive Euler-Lagrange equations from this point-like Lagrangian and show that these equations are same with the differential equations derived from the field equations of the model. Also we give two new exact asymptotically flat solutions to these equations and investigate some thermodynamic properties of these black holes.
No-scale and scale-separated flux vacua from IIA on G2 orientifolds
Authors: Farakos Fotis , Tringas George , Van Riet Thomas
Published: July 2020

We discuss flux compactifications of IIA string theory on G2 holonomy spaces with O2/O6-planes to three dimensions and find two classes of solutions: (1) No-scale Minkowski vacua from NSNS 3-form fluxes and RR 4-form fluxes. (2) By adding Romans mass we find AdS$$_3$$3vacua for which the AdS scale can be decoupled completely from the KK scale while the solution is at tunable weak coupling and large volume. For the AdS$$_3$$3vacuum we only have a proper 3D description (i.e. smeared orientifold description) of the solution like the 4D analogue of IIA moduli stabilization from fluxes and O6-planes. This 3D description reveals that moduli with non-compact moduli spaces can be stabilized at the classical level. For both types of vacua we can have supersymmetry or not.
Complexity factor for charged dissipative dynamical system
Authors: Sharif M. , Tariq Saher
Published: July 2020

In this paper, we examine the complexity factor for a dynamical spherical system with dissipative charged anisotropic fluid. We evaluate the Einstein-Maxwell field equations and structure scalars using Bel’s approach which help to discuss the structure as well as evolution of a self-gravitating system. We measure the complexity factor for the pattern of evolution through the homologous condition and homogeneous expansion. We also analyze the stability of vanishing complexity condition for dissipative and non-dissipative fluids. It is found that the complexity as well as stability of the spherical system increases and decreases, respectively, under the effects of electromagnetic field.
Enhancement of Hazy Images Using Atmospheric Light Estimation Technique
Authors: Mondal Kalimuddin , Rabidas Rinku , Dasgupta Rajdeep , Midya Abhishek , Chakraborty Jayasree
Published: July 2020

Images captured in degraded weather conditions often suffer from bad visibility. Pre-existing haze removal methods, the ones that are effective are computationally complex too. In common de-hazing approaches, estimation of atmospheric light is not achieved properly as a consequence, haze is not removed significantly from the sky region. In this paper, an efficient method of haze removal from a single image is introduced. To restore haze-free images comprising of both sky as well as nonsky regions, we developed a linear model to predict atmospheric light and estimated the transmission map using the dark channel prior followed by an application of a guided filter for quick refinement. Several experiments were conducted on a large variety of images, both reference and nonreference, where the proposed image de-hazing algorithm outperforms most of the prevalent algorithms in terms of perceptual visibility of the scene and computational efficiency. The proposed method has been empirically measured through quantitative and qualitative evaluations while retaining structure, edges, and improved color.
Random Response of Multi-Segment Beam May Exceed Response of Homogeneous Counterparts by Order of Magnitude
Authors: Fang T. , Elishakoff I. , Jiang C.
Published: July 2020

This paper investigates the dynamic properties of an inhomogeneous, Bernoulli–Euler multi-segment beam composed of different materials. To the best of knowledge of the authors, the problem of random vibrations of beams composing of different chunks of the beams, namely, strong and weak parts, has not been studied in the literature. In this paper, exact solution of the natural frequencies and associated mode shapes of the multi-segment Bernoulli–Euler beam are obtained using Krylov–Duncan functions, followed by free, forced, and random vibration analyses using the normal mode method. Special emphasis is placed on two special configurations of multi-segment beam, namely, the ‘rigid-soft-rigid beam’ (RSR beam) and ‘soft-rigid-soft beam’ (SRS beam) as simplest manifestations of the multi-chunked structures. Some remarkable properties exhibited by the dynamic response of multi-segment beam are demonstrated through this work, which may be of considerable engineering significance, and could not have been anticipated in advance, especially quantitatively.
Nonlinear Connection Stiffness Identification of Heritage Timber Buildings Using a Temperature-Driven Multi-Model Approach
Authors: Yang Qingshan , Lyu Mengning , Zhu Xinqun
Published: July 2020

‘Que-Ti’ is an important component in typical Tibetan heritage timber buildings and it performs similar to corbel brackets connecting beam and column in modern structures. It transfers shear, compression and bending moment by slippage and deformation of components as well as limited joint rotation. A rigorous analytical model of ‘Que-Ti’ is needed for predicting the behavior of a timber structure under extreme loadings. Few researches have been done on this topic, particularly with the parameters describing the performances of this connection subjected to external loads. In this paper, a new temperature-driven multimodel approach is proposed to identify the stiffness parameters of a ‘Que-Ti’ connection in its operating environment. Models with nonlinear compression and rotational springs have been developed to take into account the change of mechanical behavior of the ‘Que-Ti’ affected by the temperature variation in typical heritage Tibetan buildings. The column–beam connection is modeled as two nonlinear rotational springs and one nonlinear compressive spring. Ambient temperature variation is treated as a force function in the input (temperature)–output (local mechanical strains) relationship, and stiffness identification is conducted iteratively via correlating the calculated strain responses with measured data. The nonlinear model of the joint is reproduced with a number of linear local models in different deformation scenarios that are corresponding to different temperature ranges. The stiffness parameters can be identified using a multimodel approach. Numerical results show that the method is effective and reliable to identify the nonlinear connection stiffness of the ‘Que-Ti’ accurately with the temperature change even with 10% noise in measurements. The monitoring data from a long-term monitoring system installed in a typical heritage Tibetan building is used to further verify the method. The experimental results show that the identified stiffness by the proposed method with nonlinear connection stiffness model can get better results than that obtained from the linear connection stiffness model.
Time-Domain Spectral Finite Element Method for Modeling Second Harmonic Generation of Guided Waves Induced by Material, Geometric and Contact Nonlinearities in Beams
Authors: He Shuai , Ng Ching-Tai , Yeung Carman
Published: July 2020

This study proposes a time-domain spectral finite element (SFE) method for simulating the second harmonic generation (SHG) of nonlinear guided wave due to material, geometric and contact nonlinearities in beams. The time-domain SFE method is developed based on the Mindlin–Hermann rod and Timoshenko beam theory. The material and geometric nonlinearities are modeled by adapting the constitutive relation between stress and strain using a second-order approximation. The contact nonlinearity induced by breathing crack is simulated by bilinear crack mechanism. The material and geometric nonlinearities of the SFE model are validated analytically and the contact nonlinearity is verified numerically using three-dimensional (3D) finite element (FE) simulation. There is good agreement between the analytical, numerical and SFE results, demonstrating the accuracy of the proposed method. Numerical case studies are conducted to investigate the influence of number of cycles and amplitude of the excitation signal on the SHG and its performance in damage detection. The results show that the amplitude of the SHG increases with the numbers of cycles and amplitude of the excitation signal. The amplitudes of the SHG due to material and geometric nonlinearities are also compared with the contact nonlinearity when a breathing crack exists in the beam. It shows that the material and geometric nonlinearities have much less contribution to the SHG than the contact nonlinearity. In addition, the SHG can accurately determine the crack location without using the reference data. Overall, the findings of this study help further advance the use of SHG for damage detection.
A Two-Step Drive-By Bridge Damage Detection Using Dual Kalman Filter
Authors: Li Jiantao , Zhu Xinqun , Law Siu-Seong , Samali Bijan
Published: July 2020

Drive-by bridge inspection using acceleration responses of a passing vehicle has great potential for bridge structural health monitoring. It is, however, known that the road surface roughness is a big challenge for the practical application of this indirect approach. This paper presents a new two-step method for the bridge damage identification from only the dynamic responses of a passing vehicle without the road surface roughness information. A state-space equation of the vehicle model is derived based on the Newmark-[Formula: see text] method. In the first step, the road surface roughness is estimated from the dynamic responses of a passing vehicle using the dual Kalman filter (DKF). In the second step, the bridge damage is identified based on the interaction force sensitivity analysis with Tikhonov regularization. A vehicle–bridge interaction model with a wireless monitoring system has been built in the laboratory. Experimental investigation has been carried out for the interaction force and bridge surface roughness identification. Results show that the proposed method is effective and reliable to identify the interaction force and bridge surface roughness. Numerical simulations have also been conducted to study the effectiveness of the proposed method for bridge damage detection. The vehicle is modeled as a 4-degrees-of-freedom half-car and the bridge is modeled as a simply-supported beam. The local bridge damage is simulated as an elemental flexural stiffness reduction. Effects of measurement noise, surface roughness and vehicle speed on the identification are discussed.The results show that the proposed drive-by inspection strategy is efficient and accurate for a quick review on the bridge conditions.
Correlation-Based Damage Identification and Quantification Using Modal Kinetic Energy Change
Authors: Joseph J. T. , Chan T. H. T. , Nguyen K.-D.
Published: July 2020

Many existing damage identification or quantification methods can be employed only if the internal and external mass changes are negligible when tested at two different states of a structure. This paper presents a new Modal Kinetic Energy (MKE)-based method to detect and quantify damage using modal properties of structures, which can be employed even in situations when mass change is not more than a certain extent. A new damage sensitivity parameter has been developed using measured modal characteristics of baseline structure. The MKE change (MKEC) concept is then employed to locate damage and to estimate relative perturbation at each element. The relative damage extent vector is estimated by searching the best correlation between the analytical and experimental MKEC vectors with the help of genetic algorithm optimization tool. The extent of damage is calculated after computing damage scaling coefficient using measured eigenvalue change vector. A numerical study is carried out on a simply supported single span beam to confirm its performance under various test conditions. The robustness of the proposed MKE method and the significance of mass variation in the damage detection approach are evaluated by comparing the damage quantification results with a traditional approach. Finally, the proposed damage detection method is applied on a two-span simply supported beam for single and multiple damage scenarios by extracting the modal properties experimentally. The results revealed that the proposed approach is capable of detecting and estimating single and multiple damages with reasonable accuracy even in moderate noise contaminated and mass change environments.
Damage Detection in Initially Nonlinear Structures Based on Variational Mode Decomposition
Authors: Xin Yu , Li Jun , Hao Hong
Published: July 2020

Nonlinear characteristics in the dynamic behaviors of civil structures degrade the performance of damage detection of the linear theory based traditional time- and frequency-domain methods. To overcome this challenge, this paper proposes a damage detection approach for nonlinear structures based on Variational Mode Decomposition (VMD). In this approach, the measured dynamic responses from nonlinear structures under earthquake excitations are adaptively decomposed into a finite number of monocomponents by using VMD. Each decomposed mono-component represents an amplitude modulated and frequency modulated (AMFM) signal with a limited frequency bandwidth. Hilbert transform is then employed to identify the instantaneous modal parameters of the decomposed monomodes, including instantaneous frequencies and mode shapes. Based on the identified modal parameters from the decomposed structural dynamic responses, two damage indices are defined to identify the location and severity of structural damage, respectively. To validate the effectiveness and accuracy of the proposed approach, a nonlinear seven-storey shear building model with four different damage cases under earthquake excitations is used in the numerical studies. In experimental verifications, data from shake table tests on a 12-storey scaled reinforced concrete frame structure with different earthquake excitations are analyzed with the proposed approach. The results in both numerical studies and experimental validations demonstrate that the proposed approach can be successfully applied for nonlinear structural damage identification.
Structural Deterioration Localization Using Enhanced Autoregressive Time-Series Analysis
Authors: Monavari Benyamin , Chan Tommy H. T. , Nguyen Andy , Thambiratnam David P. , Nguyen Khac-Duy
Published: July 2020

Irrespective to how well structures were built, they all deteriorate. Herein, deterioration is defined as a slow and continuous reduction of structural performance, which if prolonged can lead to damage. Deterioration occurs due to different factors such as ageing, environmental and operational (E&O) variations including those due to service loads. Structural performance can be defined as load-carrying capacity, deformation capacity, service life and so on. This paper aims to develop an effective method to detect and locate deterioration in the presence of E&O variations and high measurement noise content. For this reason, a novel vibration-based deterioration assessment method is developed. Since deterioration alters the unique vibration characteristics of a structure, it can be identified by tracking the changes in the vibration characteristics. This study uses enhanced autoregressive (AR) time-series models to fit the vibration response data of a structure. Then, the statistical hypotheses of chi-square variance test and two-sample [Formula: see text]-test are applied to the model residuals. To precisely evaluate changes in the vibration characteristics, an integrated deterioration identification (DI) is defined using the calculated statistical hypotheses and a Hampel filter is used to detect and remove false positive and negative results. Model residual is the difference between the predicted signal from the time series model and the actual measured response data at each time interval. The response data of two numerically simulated case studies of 3-storey and 20-storey reinforced concrete (RC) shear frames contaminated with different noise contents demonstrate the efficacy of the proposed method. Multiple deterioration and damage locations, as well as preventive maintenance actions, are also considered in these case studies. Furthermore, the method was successfully verified utilizing measured data from an experiment carried out on a box-girder bridge (BGB) structure.
An Effective Framework for Performance Evaluation of Reinforced Concrete Beams Under Impact Loadings
Authors: Zhao Wuchao , Ye Jihong
Published: July 2020

Extreme actions, such as impact loads, contain many uncertainties and hence, may not be analyzed by a deterministic approach. In this paper, an effective framework for performance evaluation of reinforced concrete (RC) beams subjected to impact loadings is proposed. For this purpose, a simple yet effective model considering the shear-flexural interaction is developed based on available impact test results. By incorporating the shear effect, both the maximum displacement and impact force are well predicted, by which the proposed model for the impact analysis of RC beams is validated. The joint probability density function (PDF) of two damage indexes, i.e. local drift ratio and overall support rotation, is used to represent the local shear damage degree and the overall flexural damage degree. Taking advantage of the probabilistic framework and the effective model, reliability analysis of the RC beams under different impact scenarios is performed. The damage, described in this study by the joint PDF, is highly affected by the combination of impact mass and velocity. Thus, the mass–velocity ([Formula: see text]–[Formula: see text] diagrams for various performance levels are generated for the damage assessment of the RC beams. Furthermore, the contribution of the local and global responses to the failure probability is quantified using the proposed probabilistic framework.
Structural System Identification of Elevated Steel Water Tank Using Ambient Vibration Test and Calibration of Numerical Model
Authors: Alembagheri Mohammad , Rashidi Maria , Seyedkazemi Mohammad
Published: July 2020

This research aims to investigate the feasibility of using ambient vibration testing for system identification of an elevated water tank. To identify the natural dynamic properties, the experimental study is carried out on an elevated steel water tank located in Tehran. The tank is instrumented with a sensitive velocimeter sensor (microtremor), and the ambient velocity of the tank is recorded for 30[Formula: see text]min in three orthogonal axes. Employing the peak-picking method in the frequency domain, the fundamental frequency of the tank is determined as about 1.9[Formula: see text]Hz. Then, the numerical model of the tank is generated and calibrated based on the obtained data. In the primary modeling, the values of natural frequencies of the tank are in good agreement with the results of the ambient vibration data. This finding is judged to be reasonable considering no clear sign of corrosion in the steel material.
Weyl modules and Weyl functors for hyper-map algebras
Authors: Bianchi Angelo , Chamberlin Samuel
Published: July 2020

We investigate the representations of the hyperalgebras associated to the map algebras [Formula: see text], where [Formula: see text] is any finite-dimensional complex simple Lie algebra and [Formula: see text] is any associative commutative unitary algebra with a multiplicatively closed basis. We consider the natural definition of the local and global Weyl modules, and the Weyl functor for these algebras. Under certain conditions, we prove that these modules satisfy certain universal properties, and we also give conditions for the local or global Weyl modules to be finite-dimensional or finitely generated, respectively.
Classification of pointed fusion categories of dimension p3 up to weak Morita Equivalence
Authors: Maya Kevin , Mejía Castaño Adriana , Uribe Bernardo
Published: July 2020

We give a complete classification of pointed fusion categories over [Formula: see text] of global dimension [Formula: see text] for [Formula: see text] any odd prime. We proceed to classify the equivalence classes of pointed fusion categories of dimension [Formula: see text] and we determine which of these equivalence classes have equivalent categories of modules.
Finite symmetric tensor categories with the Chevalley property in characteristic 2
Authors: Etingof Pavel , Gelaki Shlomo
Published: July 2020

We prove an analog of Deligne’s theorem for finite symmetric tensor categories [Formula: see text] with the Chevalley property over an algebraically closed field [Formula: see text] of characteristic [Formula: see text]. Namely, we prove that every such category [Formula: see text] admits a symmetric fiber functor to the symmetric tensor category [Formula: see text] of representations of the triangular Hopf algebra [Formula: see text]. Equivalently, we prove that there exists a unique finite group scheme [Formula: see text] in [Formula: see text] such that [Formula: see text] is symmetric tensor equivalent to [Formula: see text]. Finally, we compute the group [Formula: see text] of equivalence classes of twists for the group algebra [Formula: see text] of a finite abelian [Formula: see text]-group [Formula: see text] over an arbitrary field [Formula: see text] of characteristic [Formula: see text], and the Sweedler cohomology groups [Formula: see text], [Formula: see text], of the function algebra [Formula: see text] of [Formula: see text].
Group gradings and actions of pointed Hopf algebras
Authors: Bahturin Yuri , Montgomery Susan
Published: July 2020

We study actions of pointed Hopf algebras on matrix algebras. Our approach is based on known facts about group gradings of matrix algebras [Y. Bahturin, S. Sehgal and M. Zaicev, Group gradings on associative algebras, J. Algebra 241 (2001) 667–698] and other sources.
An Empirical Study on Geotagging Technology Adoption Among the Social Networking Sites (SNSs) Users: The Moderating Effect of Geotagg’s Use Frequency
Authors: Haque Md. Ziaul , Qian Aimin , Amin Muhammad , Islam Tania
Published: July 2020

Due to the outstanding growth of geotagging technology usage among the social networking sites (SNSs) users, research is needed to better understand how SNSs users accept and use this technology. This study explores the factors that affect the adoption of geotagging technology among the SNSs users integrating personal innovativeness in IT (PIIT) with UTAUT. By using structured questionnaire survey, 390 data were collected. Statistical analysis techniques, such as SPSS AMOS and partial least square method, based on structural equation modelling (SEM), were used to analyse the collected data. Integrated UTAUT fulfills all criterion of model fitness. Interestingly, PIIT properly explains the personal characteristics of SNSs users in UTAUT framework. PIIT has impact on all UTAUT exogenous constructs except effort expectancy as well as on behavioural intention. Two new paths among the predictor variables (e.g. facilitating condition to effort expectancy and effort expectancy to performance expectancy) are statistically significant. All constructs of UTAUT except effort expectancy have substantial positive effect on SNSs users’ intention to adopt geotagging technology. Geotagg’s use frequency strongly moderated the different relationships in the integrated UTAUT model. The study will succor different tourism firms, restaurants and SNSs service providers to maximise the adoption of geotagging technology use. It contributes to knowledge by adding new moderator, new paths as well as integrating personal characteristics (e.g. PIIT) in UTAUT.
Priority Challenges of University Technology Transfer with Interpretative Structural Modeling and MICMAC Analysis
Authors: Quiñones Renissa S. , Caladcad June Anne A. , Quiñones Hubert G. , Castro Charena J. , Caballes Shirley Ann A. , Abellana Dharyll Prince M. , Jabilles Eula Margareth Y. , Himang Celbert M. , Ocampo Lanndon A.
Published: July 2020

Translating university technology via the university–industry route faces an array of challenges. Subsequently, understanding the interrelationships of these challenges hopes to provide a better outlook on the complex nature of the university technology transfer (UTT) process. Such an agenda remains a gap in the domain literature. To advance this oversight, this study intends to identify the UTT challenges and determine their complex contextual relationships. The interpretative structural modeling, together with the MICMAC analysis, was sequentially adopted to derive the overarching structure of the challenges of UTT. A case study in a public university in the Philippines was conducted to carry out these objectives. Findings show that time constraints, knowledge being too theoretical, high costs of managing joint research projects, complex organizational structure, institutional bureaucracy, geographic distance, and lack of national benchmark are driving challenges that influence other challenges in impeding UTT in the representative Philippine university. These findings provide policy insights to key decision-makers and stakeholders on the success of technology transfers.
Effect of La0.67Sr0.33 MnO3 Insertion Layer on the Ferroelectric and Resistive Switching Behaviors of PbZr0.52Ti0.48O3/Nb:SrTiO3 Heterostructures
Authors: Dong Jing Yi , Bai Yu , Zheng Hang Yu , Huang He Yang , Lin Jun Liang , Zhang Fan , Wang Chao , Wang Zhan Jie
Published: July 2020

Recently, ferroelectric resistive switching (RS) effect in the ferroelectric/semiconductor heterostructures has been widely studied and the RS performance has been greatly improved. However, the relationships between ferroelectric and RS behaviors as well as interface structure of ferroelectric/semiconductor heterostructures need to be further studied. Herein, a [Formula: see text][Formula: see text]MnO3 (LSMO) layer with the thickness of 7 nm is inserted into [Formula: see text][Formula: see text]O3/Nb:SrTiO3 (PZT/NSTO) heterostructures, and its effects on the ferroelectric and RS behaviors are investigated. The PZT/NSTO heterostructures show significantly asymmetric ferroelectric loops, and the RS ratio in which can reach to three orders of magnitude. However, by inserting the LSMO layer, the ferroelectric loops became relatively symmetric, but the RS effect almost disappeared. It can be considered that the LSMO layer affects the interfacial energy band structure of the PZT/NSTO heterostructures, which makes ferroelectric polarization lose its effect on the modulation of the depletion layer width. Therefore, the existence of the adjustable depletion layer is very important for the RS effect of ferroelectric/semiconductor heterostructures.