bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uniform slip rates of the Altyn Tagh and the Kunlun faults likely reflect lateral variation of frictional strength of the faults
Authors: Zhu Xiaojie , He Jiankun , Xiao Jie , Wang Xinguo 
Published: May 2020

AbstractThe slip rate predicted from geodetic and geomorphological measurements is quite uniform on ~800–1,000 km length of the Altyn Tagh and the Kunlun faults. GPS velocity field documents that tectonic loading on the two active faults changes greatly along their strikes. To explore the mechanical relationship between far‐field tectonic loading and fault slip‐rate accumulation, we built a 3D viscoelastic finite‐element model with fault motion governed by frictional strength of contact interfaces. Based on numerical experiments, it is found that the observed uniform slip rate could reflect lateral variation of frictional strength along fault strike. Variation of predicted frictional coefficient ranges from ~0.13 to ~0.02, verifying that the two active faults must be weak for their mechanical strength. In addition, the good fitness between the relatively weak segment of faults and the location of strong earthquakes suggests that seismic activity along the two faults could be related to their frictional strength.
A case–case study comparing the individual risk factors and symptomatology of Salmonella Heidelberg and Salmonella Typhimurium in Ontario in 2015, following implementation of the Ontario Investigation Tools
Authors: Paphitis Katherine , Pearl David L. , Berke Olaf , McEwen Scott A. , Trotz‐Williams Lise 
Published: May 2020

AbstractSalmonella Heidelberg and Salmonella Typhimurium are among the most common serotypes responsible for human salmonellosis in Ontario. Introduction of the Ontario Investigation Tools (OIT) in 2014 allowed for standardized case investigation and reporting. This study compared the risk factors and symptomatology for sporadic S. Heidelberg and S. Typhimurium cases reported in Ontario in 2015, following implementation of the OIT. Multilevel logistic regression models were applied to assess associations between serotype and individual‐level demographic characteristics, exposures and symptoms for sporadic confirmed cases of S. Heidelberg and S. Typhimurium in Ontario in 2015. There were 476 sporadic cases of S. Typhimurium (n = 278) and S. Heidelberg (n = 198) reported in Ontario in 2015. There were significant associations between the odds of the isolate from a case being one of these serotypes, and travel, consumption of sprouts (any type), contact with reptiles and development of malaise, fever or bloody diarrhoea. The S. Typhimurium and S. Heidelberg cases differed in both symptom presentation and risk factors for illness. Case–case comparisons of Salmonella serotypes have some advantages over case–control studies in that these are less susceptible to selection and recall bias while allowing for rapid comparison of cases to identify potential high‐risk exposures that are unique to one of the serotypes when compared to the other. Comparing cases of two different Salmonella serotypes can help to highlight risk factors that may be uniquely associated with one serotype, or more strongly associated with one serotype compared to another. This information may be useful for understanding relative source attribution between common serotypes of Salmonella.
Identifying the environmental drivers of Campylobacter infection risk in southern Ontario, Canada using a One Health approachs
Authors: Cousins Melanie , Sargeant Jan M. , Fisman David N. , Greer Amy L. 
Published: May 2020

AbstractBackgroundCampylobacter bacteria infect both humans and animals. Sources of human exposure include contaminated food and water, contact with animals and/or their faeces, and contact with infected individuals. The objectives of this study were to: (a) identify environmental conditions associated with the occurrence of Campylobacter in humans in four regions of Ontario, and (b) identify pooled measures of effect across all four regions and potential sources of heterogeneity.MethodsTo address objective 1, human Campylobacter cases from four health regions of Ontario, Canada were analysed using negative binomial regression and case cross‐over analysis to identify relationships between environmental factors (temperature, precipitation and hydrology of the local watershed) and the risk of human infection. To address objective 2, meta‐analytic models were used to explore pooled measures of effect and when appropriate, meta‐regression models were used to explore potential sources of heterogeneity.ResultsHuman incidence exhibited strong seasonality with cases peaking in the late spring and summer. There was a decreasing yearly effect in three of the four health regions. A significant pooled effect was found for mean temperature after a 1‐week lag (OR = 1.03, 95% CI 1.02, 1.04). No significant pooled effects were found for precipitation or water flow. However, increased precipitation was associated with lower odds of campylobacteriosis in Wellington and York regions at 2‐ and 3‐week lags, respectively, from the case cross‐over analysis.ConclusionThese results demonstrate that a climatic factor (specifically, mean temperature in the week prior) was associated with human case occurrence after a biologically plausible time period, but hydrologic factors are not.
Creep Failure Behavior of Notched Structure in the Simulated Steam Turbine Rotor: Experimental and Damage Analysis
Authors: Niu Tian-Ye , Gong Cheng , Gong Jian-Guo , Xuan Fu-Zhen 
Published: May 2020

Abstract
Notched structures widely exist in steam turbine components in fossil power plant, e.g., the groove of the rotor, etc. Previous studies indicate that creep failures occur at the groove of the rotor or the adjacent regions. Thus, it is essential to study the creep failure behavior of the notched structures for the safe operation of the system. In this work, creep tests of the simulated steam turbine component have been conducted at the temperature of 605 °C, and the creep-damage constitutive equation is used to track the evolution behavior of creep strain and damage of this component. The influence of structural and loading configurations on creep failure behavior of the component is discussed. Results demonstrate that the shearing failure at the contact area between the blade root and the rotor is observed for the tested component, while the cracking at the groove of the rotor is not found. Creep-damage constitutive equation employed in this work could provide an adequate solution of the simulated component. Parametric studies indicate that creep crack initiation and creep failure of the simulated components may occur at the contact region (i.e., between the blade root and the rotor) and the groove of the rotor, which is closely related to structural and loading configurations of the components.
Experimental Validation of an Info-Gap Uncertainty Model for a Robustness Analysis of Structural Responses
Authors: Kuczkowiak Antoine , Cogan Scott , Ouisse Morvan , Foltête Emmanuel , Corus Mathieu 
Published: May 2020

Abstract
The aim of this work is to propose an indicator, based on the info-gap approach, which assesses the robustness of the dynamic response of the model of a structure to lack of knowledge in the associated eigensolutions. The info-gap uncertainty model for the eigensolutions is constructed mode by mode based on a set of experimentally identified eigensolutions obtained from tests on a set of nominally identical structures. A robustness analysis is then performed, which provides a useful bound to the maximum response levels that are consistent with the defined uncertainty, thus allowing to extrapolate to a population of untested structures. The proposed methodology is validated experimentally on a simple structure composed of two plates clamped together on one side. Uncertainty is introduced by adding lumped masses at random locations. A subset of these test results is used to construct the info-gap model of the eigenproperties and the remaining data are used to confirm that the robustness curve usefully bounds the observed maximum responses.
Control Framework and Integrative Design Method for an Adaptive Wind Turbine Blade
Authors: Khakpour Nejadkhaki Hamid , Hall John F. 
Published: May 2020

Abstract
A control framework and integrative design method for an adaptive wind turbine blade is presented. The blade is adapted by actively transforming the twist angle distribution (TAD) along the blade. This can alleviate fatigue loads and improve wind capture. In this paper, we focus on wind capture. The proposed design concept consists of a rigid spar that is surrounded by a series of flexible blade sections. Each section has two zones of stiffness. The sections are actuated at each end to deform the TAD. A quasi-static control technique is proposed for the TAD. The controller sets the position of the blade actuators that shape the TAD during steady-state operation. A design procedure is used to define the required TAD as a function of the wind speed. This is based on an optimization procedure that minimizes the deviation between the actual TAD and that found in the aerodynamic design. The design inputs for this optimization problem include the stiffness for each zone of the section, and the actuator locations along the blade. Given the optimal TAD at each wind speed, the free position of the blade is established using a dynamic programming technique. The position is selected based on minimal actuation energy according to wind conditions at any installation site. The proposed framework is demonstrated using a National Renewable Energy Laboratory (NREL) certified wind turbine model with recorded wind data. An increase in efficiency of 3.8% with only a deviation of 0.34% from the aerodynamic TAD is observed.
Device-Level Multidimensional Thermal Dynamics With Implications for Current and Future Wide Bandgap Electronics
Authors: Lundh James Spencer , Song Yiwen , Chatterjee Bikramjit , Baca Albert G. , Kaplar Robert J. , Armstrong Andrew M. , Allerman Andrew A. , Klein Brianna A. , Kendig Dustin , Kim Hyungtak , Choi Sukwon 
Published: May 2020

Abstract
Researchers have been extensively studying wide-bandgap (WBG) semiconductor materials such as gallium nitride (GaN) with an aim to accomplish an improvement in size, weight, and power of power electronics beyond current devices based on silicon (Si). However, the increased operating power densities and reduced areal footprints of WBG device technologies result in significant levels of self-heating that can ultimately restrict device operation through performance degradation, reliability issues, and failure. Typically, self-heating in WBG devices is studied using a single measurement technique while operating the device under steady-state direct current measurement conditions. However, for switching applications, this steady-state thermal characterization may lose significance since the high power dissipation occurs during fast transient switching events. Therefore, it can be useful to probe the WBG devices under transient measurement conditions in order to better understand the thermal dynamics of these systems in practical applications. In this work, the transient thermal dynamics of an AlGaN/GaN high electron mobility transistor (HEMT) were studied using thermoreflectance thermal imaging and Raman thermometry. Also, the proper use of iterative pulsed measurement schemes such as thermoreflectance thermal imaging to determine the steady-state operating temperature of devices is discussed. These studies are followed with subsequent transient thermal characterization to accurately probe the self-heating from steady-state down to submicrosecond pulse conditions using both thermoreflectance thermal imaging and Raman thermometry with temporal resolutions down to 15 ns.
Presleep α-Lactalbumin Consumption Does Not Improve Sleep Quality or Time-Trial Performance in Cyclists
Authors: MacInnis Martin J. , Dziedzic Christine E. , Wood Emily , Oikawa Sara Y. , Phillips Stuart M. 
Published: May 2020

We tested the hypothesis that presleep consumption of α-lactalbumin (LA), a fraction of whey with a high abundance of tryptophan, would improve indices of sleep quality and time-trial (TT) performance in cyclists relative to an isonitrogenous collagen peptide (CP) supplement lacking tryptophan. Using randomized, double-blind, crossover designs, cyclists consumed either 40 g of LA or CP 2 hr prior to sleep. In Study 1, six elite male endurance track cyclists (age 23 ± 6 years, 70.2 ± 4.4 ml·kg−1·min−1) consumed a supplement for three consecutive evenings before each 4-km TT on a velodrome track, whereas in Study 2, six well-trained cyclists (one female; age 24 ± 5 years, 66.9 ± 8.3 ml·kg−1·min−1) consumed a supplement the evening before each 4-km TT on a stationary cycle ergometer. Indices of sleep quality were assessed with wrist-based actigraphy. There were no differences between the CP and LA supplements in terms of total time in bed, total sleep time, or sleep efficiency in Study 1 (LA: 568 ± 71 min, 503 ± 67 min, 88.3% ± 3.4%; CP: 546 ± 30 min, 479 ± 35 min, 87.8% ± 3.1%; p = .41, p = .32, p = .74, respectively) or Study 2 (LA: 519 ± 90 min, 450 ± 78 min, 87.2% ± 7.6%; CP: 536 ± 62 min, 467 ± 57 min, 87.3% ± 6.4%; p = .43, p = .44, p = .97, respectively). Similarly, time to complete the 4-km TT was unaffected by supplementation in Study 1 (LA: 274.9 ± 7.6 s; CP: 275.5 ± 7.2 s; p = .62) and Study 2 (LA: 344.3 ± 22.3 s; CP: 343.3 ± 23.0 s; p = .50). Thus, relative to CP, consuming LA 2 hr prior to sleep over 1–3 days did not improve actigraphy-based indices of sleep quality or 4-km TT performance in cyclists.
Clumped isotope constraints on changes in latest Pleistocene hydroclimate in the northwestern Great Basin: Lake Surprise, California
Authors: Santi L.M. , Arnold A.J. , Ibarra D.E. , Whicker C.A. , Mering J.A. , Lomarda R.B. , Lora J.M. , Tripati A. 
Published: May 2020

AbstractDuring the Last Glacial Maximum (LGM) and subsequent deglaciation, the Great Basin in the southwestern United States was covered by numerous extensive closed-basin lakes, in stark contrast with the predominately arid climate observed today. This transition from lakes in the Late Pleistocene to modern aridity implies large changes in the regional water balance. Whether these changes were driven by increased precipitation rates due to changes in atmospheric dynamics, decreased evaporation rates resulting from temperature depression and summer insolation changes, or some combination of the two remains uncertain. The factors contributing to these large-scale changes in hydroclimate are critical to resolve, given that this region is poised to undergo future anthropogenic-forced climate changes with large uncertainties in model simulations for the 21st century. Furthermore, there are ambiguous constraints on the magnitude and even the sign of changes in key hydroclimate variables between the Last Glacial Maximum and the present day in both proxy reconstructions and climate model analyses of the region. Here we report thermodynamically derived estimates of changes in temperature, precipitation, and evaporation rates, as well as the isotopic composition of lake water, using clumped isotope data from an ancient lake in the northwestern Great Basin, Lake Surprise (California). Compared to modern climate, mean annual air temperature at Lake Surprise was 4.7 °C lower during the Last Glacial Maximum, with decreased evaporation rates and similar precipitation rates to modern. During the mid-deglacial period, the growth of Lake Surprise implied that the lake hydrologic budget briefly departed from steady state. Our reconstructions indicate that this growth took place rapidly, while the subsequent lake regression took place over several thousand years. Using models for precipitation and evaporation constrained from clumped isotope results, we determine that the disappearance of Lake Surprise coincided with a moderate increase in lake temperature, along with increasing evaporation rates outpacing increasing precipitation rates. Concomitant analysis of proxy data and climate model simulations for the Last Glacial Maximum are used to provide a robust means to understand past climate change, and by extension, predict how current hydroclimates may respond to expected future climate forcings. We suggest that an expansion of this analysis to more basins across a larger spatial scale could provide valuable insight into proposed climate forcings, and aid in climate model process depiction. Ultimately, our analysis highlights the importance of temperature-driven evaporation as a mechanism for lake growth and retreat in this region.
Investigating the construct validity of a haptic virtual caries simulation for
dental education
Authors: Osnes Cecilie , Duke Alice , Wu Jianhua , Franklin Paul , Mushtaq Faisal , Keeling Andrew 
Published: May 2020

Introduction
Teaching dental caries removal is limited by the material and methods
available in the preclinical teaching space. Plastic teeth do not simulate the
tactile feel of a lesion and natural teeth do not allow for standardised
training and assessment. A novel method for simulating caries has been
reported. Here, to investigate the construct validity of a caries simulation,
whether haptic simulation could contribute to the understanding of caries
removal, the performance of first-year dental students on the haptic simulation
exercise is compared with that of experienced dentists.

Method
A virtual block comprising healthy dentine, pulp, enamel and a carious
lesion with significant spread along the amelodentinal junction (ADJ) was
developed for the Simodont dental trainer. The case was presented to 112
first-year students and 17 clinicians following a 15 min training period on a
block which contained green caries and displayed live progress throughout the
exercise. All participants were given the same verbal instructions: to remove
all unsupported enamel and caries along the ADJ while retaining as much healthy
tissue as possible.

Results
Clinicians performed better than the dental novices in precision and
overall performance. Clinicians removed more material on average, except for
healthy dentine, of which similar amounts were removed by both groups.

Discussion
We presented a novel haptic caries exercise and investigated the construct
validity of the task. The simulation may bridge the gap between preclinical and
clinical dental education in caries removal.

Conclusion
Clinically experienced dentists outperformed novices on a haptic caries
simulation exercise. The exercise may be a useful tool for assessing conceptual
understanding of caries removal.
Invasive versus non-invasive assessment of valvuloarterial impedance in severe aortic stenosis
Authors: Stanberry Lisa , Ahmed Aisha , Sorajja Paul , Cavalcante Joao L , Gossl Mario 
Published: May 2020

BackgroundAs a measure of the global left ventricular afterload, valvuloarterial impedance (ZVA) can be estimated using transthoracic echocardiography (TTE) and invasive measuring methods. The objective of this study was to compare the performance of TTE in measuring ZVA with invasive haemodynamics, direct Fick and thermodilution (TD), in patients with severe aortic stenosis (AS).MethodsThis is a retrospective cohort study of 66 patients with severe AS who underwent TTE and bilateral heart catheterisation preaortic valve replacement. ZVA was calculated non-invasively from TTE and invasively using TD and Fick. The differences in measurements were estimated using a generalised estimating equation approach. The exchangeability of the measurements from different methods was evaluated under binary risk stratification rules.ResultsThe mean±SD ZVA by TTE was 4.6±1.4 vs 4.9±1.6 by TD vs 4.3±1.2 mm Hg m2/mL by Fick. From multivariate analyses, ZVA by TTE was 5.9% (95% CI −15.0 to 2.5) lower than by TD and 5.9% (95% CI −1.5 to 12.8) higher than by Fick. At the same time, ZVA by TD was 12.5% (3.0 to 22.9) higher than with Fick. Risk classifications for ZVA-based binary decision rules showed poor agreement between TTE and invasive methods (kappa ≤0.3).ConclusionsThe differences in ZVA estimates between TTE and invasive standards do not appear to exceed those between the standards. As such TTE-based estimates may be deemed acceptable as a clinical measure of global haemodynamic load. However, TTE-based and invasive measurements may not be interchangeable to identify patients at risk using binary classification rules based on ZVA.
Inducing weight loss in native ponies: is straw a viable alternative to hay?
Authors: Dosi Miranda Carlotta Maria , Kirton Roxane , Hallsworth Sarah , Keen John A , Morgan Ruth Anna 
Published: May 2020

BackgroundObesity is a growing problem in UK equine population. Achieving weight loss in obese horses and ponies at risk of laminitis is an important but often challenging objective.MethodsWe hypothesised that supplementing poor winter pasture with a mix of barley straw and hay (50:50) rather than hay alone (group B) would lead to weight loss in grazing equids over winter. For this purpose, a group of 40 horses were fed either the straw mix (group A) or hay alone (group B) over winter.ResultsOver the study period, all animals in group A (n=25) lost weight with a mean weight change of −27±17 kg, while in group B (n=15) only 3 out of 15 lost weight (20 per cent), and overall, group B gained weight (+6±18 kg).ConclusionsThis study suggests that straw is a cost‐effective and low‐energy roughage, which may be a useful alternative to hay alone when trying to induce weight loss in grazing equids over winter. There were no episodes of colic or laminitis during the study period in either group.