bluuebunny/crossref_metadata_2025 huggingface dataset:
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

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

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

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

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.
Effect of metallic Mg insertion in CoFeB/MgO interface perpendicular magnetic tunnel junction on tunnel magnetoresistance ratio observed by Synchrotron x-ray diffraction
Authors: Niwa Masaaki , Honjo Hiroaki , Kumara Loku Singgappulige Rosantha , Inoue Hirofumi , Ikeda Shoji , Tajiri Hiroo , Endoh Tetsuo
Published: May 2020

The effect of metallic Mg insertion into the CoFeB/MgO/CoFeB-based magnetic tunnel junction (MTJ) on tunnel magnetoresistance (TMR) properties was investigated using synchrotron x-ray diffraction (XRD) in the out-of-plane geometry. For the MTJ without metallic Mg insertion, both low resistance area product (RA) and TMR ratio tend to decrease as the MgO barrier becomes thinner. When the 0.1-nm-thick metallic Mg is inserted over the MgO barrier, the TMR ratio was found to enhance without increasing the RA value at the MgO thickness range of less than 1.2 nm. Whereas in case the metallic Mg is inserted under the MgO barrier, the TMR ratio tends to deteriorate without changing the RA value. From the XRD spectra, the (200) orientation of MgO with the NaCl structure was confirmed to be improved for the blanket samples with 0.1-nm-thick inserted metallic Mg over the MgO barrier. This can be interpreted as progression of a stoichiometric MgO formation by combining the excess oxygen in MgO with the inserted metallic Mg, which improves the TMR properties. In contrast, when the metallic Mg is inserted under the MgO barrier, the (200) orientation, as well as the TMR ratio, decreases with the increase in the inserted metallic Mg thickness. This can be interpreted that the island growth of inserted Mg on CoFeB and the poor wettability of MgO on the Mg may initiate the interface roughness, which outgrows the MgO/CoFeB interface roughness in the subsequent deposition process.
Aluminum metallization of III–V semiconductors for the study of proximity superconductivity
Authors: Sarney Wendy L. , Svensson Stefan P. , Leff Asher C. , Schiela William F. , Yuan Joseph O. , Dartiailh Matthieu C. , Mayer William , Wickramasinghe Kaushini S. , Shabani Javad
Published: May 2020

Managing the interaction of materials with insertion layers and nonconventional molecular beam epitaxy growth conditions allows for interfaces that are more precise but requires judicious examination of the multiple possible design variables. Here, we show a comparison between As- and Sb-containing insertion layers between Al and two binaries with different group V elements and demonstrate that antimonide layers greatly improve the interface. In addition to depositing Al at extremely slow growth rates onto cold (below 0 °C) substrates, the reactivity is particularly minimized with AlSb insertion layers, which improves interface abruptness, preserves the underlying semiconductor layer’s crystalline properties, and produces flatter superconductor surfaces.
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.
Activity of Epigenetic Inhibitors against Plasmodium falciparum Asexual and Sexual Blood Stages
Authors: Vanheer Leen N. , Zhang Hao , Lin Gang , Kafsack Björn F. C.
Published: May 2020

Earlier genetic and inhibitor studies showed that epigenetic regulation of gene expression is critical for malaria parasite survival in multiple life stages and a promising target for new antimalarials. We therefore evaluated the activity of 350 diverse epigenetic inhibitors against multiple stages of
Plasmodium falciparum
. We observed ≥90% inhibition at 10 μM for 28% of compounds against asexual blood stages and early gametocytes, of which a third retained ≥90% inhibition at 1 μM.
Sea Cucumber Intestinal Regeneration Reveals Deterministic Assembly of the Gut Microbiome
Authors: Weigel Brooke L.
Published: May 2020

The gut microbiome is pertinent to many aspects of animal health, and there is a great need for natural but tractable experimental systems to examine the processes shaping gut microbiome assembly. Here, the holothurian (sea cucumber)Sclerodactyla briareuswas explored as an experimental system to study microbial colonization in the gut, asS. briareusindividuals have the ability to completely eviscerate and rapidly regenerate their digestive organs. After induced evisceration, microbial community assembly was characterized over 20 days in regenerating animals. This study demonstrated that colonization of the sea cucumber gut was deterministic; despite immersion in a diverse consortium of environmental microbes, a specific subset of microbes proliferated in the gut, including taxa that likely conferred energetic and immune advantages to the host. Sea cucumbers have the potential to revolutionize our understanding of gut microbiome assembly, as rapid and repeatable gut tissue regeneration provides a promising and tractable experimental system.
Hierarchical Transcriptional Control of the LuxR Quorum-Sensing Regulon of Vibrio harveyi
Authors: Chaparian Ryan R. , Ball Alyssa S. , van Kessel Julia C.
Published: May 2020

Quorum sensing is important for survival of bacteria in nature and influences the actions of bacterial groups. In the relatively few studied examples of quorum-sensing-controlled genes, these genes are associated with competition or cooperation in complex microbial communities and/or virulence in a host. However, quorum sensing in vibrios controls the expression of hundreds of genes, and their functions are mostly unknown or uncharacterized. In this study, we identify the regulators of the second tier of gene expression in the quorum-sensing system of the aquaculture pathogen
Vibrio harveyi
. Our identification of regulatory networks and metabolic pathways controlled by quorum sensing can be extended and compared to other
Vibrio
species to understand the physiology, ecology, and pathogenesis of these organisms.
Assessing the Use of PCR To Screen for Shedding of Salmonella enterica in Infected Humans
Authors: Lloyd Tyler , Bender Monica , Huang Sandra , Brown Robert , Shiau Rita , Yette Emily , Shemsu Munira , Pandori Mark
Published: May 2020

Recovery from enteric bacterial illness often includes a phase of organismal shedding over a period of days to months. The monitoring of this process through laboratory testing forms the foundation of public health action to prevent further transmission. Regulations in most jurisdictions in the United States exclude individuals who continue to shed certain organisms from sensitive occupations and situations, such as food handling, providing direct patient care, or attending day care. The burden that this creates for recovering patients and their families/coworkers is great, so any effort to provide efficiency to the testing process would be of significant benefit.
Multicenter Evaluation of the Cepheid Xpert Xpress SARS-CoV-2 Test
Authors: Loeffelholz Michael J. , Alland David , Butler-Wu Susan M. , Pandey Utsav , Perno Carlo Frederico , Nava Alice , Carroll Karen C. , Mostafa Heba , Davies Emma , McEwan Ashley , Rakeman Jennifer L. , Fowler Randal C. , Pawlotsky Jean-Michel , Fourati Slim , Banik Sukalyani , Banada Padmapriya P. , Swaminathan Shobha , Chakravorty Soumitesh , Kwiatkowski Robert W. , Chu Victor C. , Kop JoAnn , Gaur Rajiv , Sin Mandy L. Y. , Nguyen Duy , Singh Simranjit , Zhang Na , Persing David H.
Published: May 2020

Nucleic acid amplification tests (NAATs) are the primary means of identifying acute infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Accurate and fast test results may permit more efficient use of protective and isolation resources and allow rapid therapeutic interventions. We evaluated the analytical and clinical performance characteristics of the Xpert Xpress SARS-CoV-2 (Xpert) test, a rapid, automated molecular test for SARS-CoV-2. Analytical sensitivity and specificity/interference were assessed with infectious SARS-CoV-2; other infectious coronavirus species, including SARS-CoV; and 85 nasopharyngeal swab specimens positive for other respiratory viruses, including endemic human coronaviruses (hCoVs).
Threats Posed by the Fungal Kingdom to Humans, Wildlife, and Agriculture
Authors: Fisher Matthew C. , Gurr Sarah J. , Cuomo Christina A. , Blehert David S. , Jin Hailing , Stukenbrock Eva H. , Stajich Jason E. , Kahmann Regine , Boone Charles , Denning David W. , Gow Neil A. R. , Klein Bruce S. , Kronstad James W. , Sheppard Donald C. , Taylor John W. , Wright Gerard D. , Heitman Joseph , Casadevall Arturo , Cowen Leah E.
Published: May 2020

The fungal kingdom includes at least 6 million eukaryotic species and is remarkable with respect to its profound impact on global health, biodiversity, ecology, agriculture, manufacturing, and biomedical research. Approximately 625 fungal species have been reported to infect vertebrates, 200 of which can be human associated, either as commensals and members of our microbiome or as pathogens that cause infectious diseases. These organisms pose a growing threat to human health with the global increase in the incidence of invasive fungal infections, prevalence of fungal allergy, and the evolution of fungal pathogens resistant to some or all current classes of antifungals.
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

During 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.
Supplemental material: Guides to understanding the aeromagnetic expression of faults in sedimentary basins: Lessons learned from the central Rio Grande rift, New Mexico
Authors: Grauch V.J.S. , Hudson Mark R.
Published: May 2020

Geosphere, December 2007, v. 3, p. 596-623, doi: 10.1130/GES00128.1. Plate 1 - Color shaded-relief image of reduced-to-pole (RTP) aeromagnetic data for the central Rio Grande rift, compiled from Sweeney et al. (2002) and Bankey et al. (2006). The colors primarily reflect the broad variations in the data, whereas the illumination (from the west) emphasizes detailed variations, especially linear features associated with faults. Selected geographic, geologic, and interpretative features are labeled. Map projection is NAD27, UTM zone 13, in units of meters. Inset shows locations and names of aeromagnetic survey areas. Map scale 1:250,000. File size is 9.2 MB.
Supplemental material: Cenozoic to Recent plate configurations in the Pacific Basin: Ridge subduction and slab window magmatism in western North America
Authors: Madsen J.K. , Thorkelson D.J. , Friedman R.M. , Marshall D.D.
Published: May 2020

Geosphere, February 2006, v. 2, p. 11-34, doi: 10.1130/GES00020.1. Movie 1 - Tectonic model for the Pacific Basin and northwestern North America from 53 Ma to 39 Ma. The file size is 1.3 MB.
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.
Case for persuasion in parental informed consent to promote rational vaccine choices
Authors: O'Neill Jennifer
Published: May 2020

There have been calls for mandatory vaccination legislation to be introduced into the UK in order to tackle the national and international rise of vaccine-preventable disease. While some countries have had some success associated with mandatory vaccination programmes, the Royal College of Paediatrics and Child Health (RCPCH) insist this is not a suitable option for the UK, a country which has seen historical opposition to vaccine mandates. There is a lack of comprehensive data to demonstrate a direct link between mandatory vaccination legislation and increased uptake. While there are examples whereby there has been an improvement, some studies suggest that comparable results can be obtained by strongly recommending vaccinations instead. The RCPCH insist that healthcare workers are ideally placed to engage and inform parents to make every interaction a ‘vaccine opportunity’. This paper calls for a principled, rational approach to interpretations of autonomy which underpin parental informed consent. MacLean’s concept of mutual persuasion could be a vehicle to ensuring parents are suitably informed of both the material risks associated with vaccine choices and to consider the rationality of their decisions, while ultimately upholding parental autonomy. It is argued that this, alongside infrastructural improvement, could create a more sustainable, long-term improvement in childhood vaccination rates in the UK than mandatory vaccination.
Physician, know thyself: implicit and explicit decision-making for mechanical thrombectomy in stroke
Authors: Fargen Kyle M , Leslie-Mazwi Thabele M , Chen Michael , Hirsch Joshua A
Published: May 2020

Few clinical situations in medical practice are as time-sensitive and and have such profound ramifications as selection of patients with acute stroke for mechanical thrombectomy (MT). Emergent large vessel occlusion has become a treatable disease with minimal numbers needed to treat to achieve a functional, long-term neurologic outcome. However, MT carries risk and many patients who are appropriately reperfused continue to have significant neurologic deficits and disability despite a successful procedure. The decision to offer or withhold MT can be complex. Frequently decisions must be made based on incomplete information or emergently while the physician is awoken from sleep or distracted while performing other procedures. A growing number of studies have examined cognitive errors and biases as they pertain to patient diagnosis and treatment in medicine. Dual process theory identifies two decision-making processes as system 1 ('implicit') and system 2 ('explicit') and describes the patterns through which decisions are formulated. The implicit system is the default pathway as it requires little effort or focus, uses mental short cuts, and is rapid; however, this pathway is subject to considerable bias and error. This manuscript reviews the mechanisms underlying the way in which physician decisions about MT are made, specifically highlighting prominent biases that may affect judgment, and reviews other important principles, such as confidence in decisions, aggressiveness to pursue MT, and strategies to improve decisions.
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

Background

As 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).

Methods

This 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.

Results

The 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).

Conclusions

The 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

Background

Obesity 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.

Methods

We 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.

Results

Over 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).

Conclusions

This 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.
On the k-error Linear Complexity of Subsequences of d-ary Sidel’nikov Sequences Over Prime Field 𝔽d
Authors: Yang Minghui , Wen Jiejing
Published: May 2020

We study the [Formula: see text]-error linear complexity of subsequences of the [Formula: see text]-ary Sidel’nikov sequences over the prime field [Formula: see text]. A general lower bound for the [Formula: see text]-error linear complexity is given. For several special periods, we show that these sequences have large [Formula: see text]-error linear complexity.
Selection Algorithms with Small Groups
Authors: Chen Ke , Dumitrescu Adrian
Published: May 2020

We revisit the selection problem, namely that of computing the [Formula: see text]th order statistic of [Formula: see text] given elements, in particular the classic deterministic algorithm by grouping and partition due to Blum, Floyd, Pratt, Rivest, and Tarjan (1973). Whereas the original algorithm uses groups of odd size at least [Formula: see text] and runs in linear time, it has been perpetuated in the literature that using smaller group sizes will force the worst-case running time to become superlinear, namely [Formula: see text]. We first point out that the usual arguments found in the literature justifying the superlinear worst-case running time fall short of proving this claim. We further prove that it is possible to use group size smaller than [Formula: see text] while maintaining the worst case linear running time. To this end we introduce three simple variants of the classic algorithm, the repeated step algorithm, the shifting target algorithm, and the hyperpair algorithm, all running in linear time.
Fast Thresholding Algorithms with Feedbacks and Partially Known Support for Compressed Sensing
Authors: Cui Kaiyan , Song Zhanjie , Han Ningning
Published: May 2020

Some works in modified compressive sensing (CS) show that reconstruction of sparse signals can obtain better results than traditional CS using the partially known support. In this paper, we extend the idea of these works to the null space tuning algorithm with hard thresholding, feedbacks ([Formula: see text]) and derive sufficient conditions for robust sparse signal recovery. The theoretical analysis shows that including prior information of partially known support relaxes the preconditioned restricted isometry property condition comparing with the [Formula: see text]. Numerical experiments demonstrate that the modification improves the performance of the NST+HT+FB, thereby requiring fewer samples to obtain an approximate reconstruction. Meanwhile, a systemic comparison with different methods based on partially known support is shown.
DIRICHLET PROBLEM OF POISSON EQUATIONS AND VARIATIONAL PRINCIPLE ON A TYPE OF FRACTAL SETS
Authors: WU YIPENG , YAO KUI , MU LEI , CHEN ZHILONG
Published: May 2020

This paper studied the level-3 Sierpinski gasket. We solved Dirichlet problem of Poisson equations and proved variational principle on the level-3 Sierpinski gasket by expressing Green’s function explicitly.
EFFECT OF FRACTIONAL DERIVATIVE PROPERTIES ON THE PERIODIC SOLUTION OF THE NONLINEAR OSCILLATIONS
Authors: EL-DIB YUSRY O. , ELGAZERY NASSER S.
Published: May 2020

A periodic solution of the time-fractional nonlinear oscillator is derived based on the Riemann–Liouville definition of the fractional derivative. In this approach, the particular integral to the fractional perturbed equation is found out. An enhanced perturbation method is developed to study the forced nonlinear Duffing oscillator. The modified homotopy equation with two expanded parameters and an additional auxiliary parameter is applied in this proposal. The basic idea of the enhanced method is to apply the annihilator operator to construct a simplified equation freeness of the periodic force. This method makes the solution process for the forced problem much simpler. The resulting equation is valid for studying all types of possible resonance states. The outcome shows that this alteration method overcomes all shortcomings of the perturbation method and leads to obtain a periodic solution.
COMPLEXITY-BASED ANALYSIS OF BRAINS’ SYNCHRONIZATION IN HUMAN–HUMAN INTERACTION
Authors: AHAMED MOHAMED RASMI ASHFAQ , BABINI MOHAMMAD HOSSEIN , PAKNIYAT NAJMEH , NAMAZI HAMIDREZA
Published: May 2020

Talking is the most common type of human interaction that people have in their daily life. Besides all conducted studies on the analysis of human behavior in different conditions, no study has been reported yet that analyzed how the brain activity of two persons is related during their conversation. In this research, for the first time, we investigate the relationship between brain activities of people while communicating, considering human voice as the mean of this connection. For this purpose, we employ fractal analysis in order to investigate how the complexity of electroencephalography (EEG) signals for two persons are related. The results showed that the variations of complexity of EEG signals for two persons are correlated while communicating. Statistical analysis also supported the result of analysis. Therefore, it can be stated that the brain activities of two persons are correlated during communication. Fractal analysis can be employed to analyze the correlation between other physiological signals of people while communicating.
Rigid trisporphyrin with 1,3,5-triazine core: Synthesis, spectroscopy, and DABCO-induced self-assembly properties
Authors: Huang Chunhua , Shen Bin , Wang Kang , Lu Jing’an , Sun Xiao’fei
Published: May 2020

A rigid Zn–trisporphyrin (1), the Zinc complex of 2,4,6-tris(5,10,15-triphenylporphyrinatozinc)-1,3,5-triazine (2) with three porphyrin moieties bridged by a rigid 1,3,5-triazine group, was synthesized and characterized by a series of spectroscopic methods including mass, 1H NMR, electronic absorption, and IR spectroscopy in addition to elemental analysis. The UV-vis spectrophotometric titration results revealed that along with the addition of the 1,4-diazabicyclo[2.2.2]octane (DABCO) form 0 to 3 equiv, 1 could form a 2:3 sandwich-type coordination cage in chloroform, which then transformed into a 1:3 open complex when the DABCO concentration was more than 3 equiv. Such DABCO-induced self- and disassembly processes were also confirmed by 1H NMR spectrophotometric titrations. In particular, it was demonstrated by comparative studies that the synergistic effect of the three porphyrin moieties linked together by the rigid 1,3,5-triazine group in 1 promoted the formation and stabilization of the 2:3 sandwich-type coordination cage. This result will be helpful towards the fabrication of various self-assembly structures based on metalloporphyrins with application potential in diverse areas such as molecular recognition and separation.
Random Forest with Self-Paced Bootstrap Learning in Lung Cancer Prognosis
Authors: Wang Qingyong , Zhou Yun , Ding Weiping , Zhang Zhiguo , Muhammad Khan , Cao Zehong
Published: May 2020

Training gene expression data with supervised learning approaches can provide an alarm sign for early treatment of lung cancer to decrease death rates. However, the samples of gene features involve lots of noises in a realistic environment. In this study, we present a random forest with self-paced learning bootstrap for improvement of lung cancer classification and prognosis based on gene expression data. To be specific, we propose an ensemble learning with random forest approach to improving the model classification performance by selecting multi-classifiers. Then, we investigate the sampling strategy by gradually embedding from high- to low-quality samples by self-paced learning. The experimental results based on five public lung cancer datasets show that our proposed method could select significant genes exactly, which improves classification performance compared to that of existing approaches. We believe that our proposed method has the potential to assist doctors in gene selections and lung cancer prognosis.
Hybrid Wolf-Bat Algorithm for Optimization of Connection Weights in Multi-layer Perceptron
Authors: Agrawal Utkarsh , Arora Jatin , Singh Rahul , Gupta Deepak , Khanna Ashish , Khamparia Aditya
Published: May 2020

In a neural network, the weights act as parameters to determine the output(s) from a set of inputs. The weights are used to find the activation values of nodes of a layer from the values of the previous layer. Finding the ideal set of these weights for training a Multi-layer Perceptron neural network such that it minimizes the classification error is a widely known optimization problem. The presented article proposes a Hybrid Wolf-Bat algorithm, a novel optimization algorithm, as a solution to solve the discussed problem. The proposed algorithm is a hybrid of two already existing nature-inspired algorithms, Grey Wolf Optimization algorithm and Bat algorithm. The novel introduced approach is tested on ten different datasets of the medical field, obtained from the UCI machine learning repository. The performance of the proposed algorithm is compared with the recently developed nature-inspired algorithms: Grey Wolf Optimization algorithm, Cuckoo Search, Bat Algorithm, and Whale Optimization Algorithm, along with the standard Back-propagation training method available in the literature. The obtained results demonstrate that the proposed method outperforms other bio-inspired algorithms in terms of both speed of convergence and accuracy.
Delving Deeper in Drone-Based Person Re-Id by Employing Deep Decision Forest and Attributes Fusion
Authors: Grigorev Aleksei , Liu Shaohui , Tian Zhihong , Xiong Jianxin , Rho Seungmin , Feng Jiang
Published: May 2020

Deep learning has revolutionized the field of computer vision and image processing. Its ability to extract the compact image representation has taken the person re-identification (re-id) problem to a new level. However, in most cases, researchers are focused on developing new approaches to extract more fruitful image representation and use it in the re-id task. The extra information about images is rarely taken into account because the traditional person re-id datasets usually do not have it. Nevertheless, the research in multimodal machine learning has demonstrated that the utilization of the information from different sources leads to better performance. In this work, we demonstrate how a person re-id problem can benefit from the utilization of multimodal data. We have used the UAV drone to collect and label the new person re-id dataset, which is composed of pedestrian images and its attributes. We have manually annotated this dataset with attributes, and in contrast to the recent research, we do not use the deep network to classify them. Instead, we employ the continuous bag-of-words model to extract the word embeddings from text descriptions and fuse it with features extracted from images. Then the deep neural decision forest is used for pedestrians classification. The extensive experiments on the collected dataset demonstrate the effectiveness of the proposed model.
Spatial Preserved Graph Convolution Networks for Person Re-identification
Authors: Li Zhaoju , Zhou Zongwei , Jiang Nan , Han Zhenjun , Xing Junliang , Jiao Jianbin
Published: May 2020

Person Re-identification is a very challenging task due to inter-class ambiguity caused by similar appearances, and large intra-class diversity caused by viewpoints, illuminations, and poses. To address these challenges, in this article, a graph convolution network based model for person re-identification is proposed to learn more discriminative feature embeddings, where a graph-structured relationship between person images and person parts are together integrated. Graph convolution networks extract common characteristics of the same person, while pyramid feature embedding exploits parts relations and learns stable representation with each person image. We achieve a very competitive performance respectively on three widely used datasets, indicating that the proposed approach significantly outperforms the baseline methods and achieves the state-of-the-art performance.
Pulmonary Nodule Detection Based on ISODATA-Improved Faster RCNN and 3D-CNN with Focal Loss
Authors: Tong Chao , Liang Baoyu , Zhang Mengze , Chen Rongshan , Sangaiah Arun Kumar , Zheng Zhigao , Wan Tao , Yue Chenyang , Yang Xinyi
Published: May 2020

The early diagnosis of pulmonary cancer can significantly improve the survival rate of patients, where pulmonary nodules detection in computed tomography images plays an important role. In this article, we propose a novel pulmonary nodule detection system based on convolutional neural networks (CNN). Our system consists of two stages, pulmonary nodule candidate detection and false positive reduction. For candidate detection, we introduce Iterative Self-Organizing Data Analysis Techniques Algorithm (ISODATA) to Faster Region-based Convolutional Neural Network (Faster R-CNN) model. For false positive reduction, a three-dimensional convolutional neural network (3D-CNN) is employed to completely utilize the three-dimensional nature of CT images. In this network, Focal Loss is used to solve the class imbalance problem in this task. Experiments were conducted on LUNA16 dataset. The results show the preferable performance of the proposed system and the effectiveness of using ISODATA and Focal loss in pulmonary nodule detection is proved.
Emote-Controlled
Authors: Kobs Konstantin , Zehe Albin , Bernstetter Armin , Chibane Julian , Pfister Jan , Tritscher Julian , Hotho Andreas
Published: May 2020

In recent years, streaming platforms for video games have seen increasingly large interest, as so-called esports have developed into a lucrative branch of business. Like for other sports, watching esports has become a new kind of entertainment medium, which is possible due to platforms that allow gamers to live stream their gameplay, the most popular platform being Twitch.tv. On these platforms, users can comment on streams in real time and thereby express their opinion about the events in the stream. Due to the popularity of Twitch.tv, this can be a valuable source of feedback for streamers aiming to improve their reception in a gaming-oriented audience. In this work, we explore the possibility of deriving feedback for video streams on Twitch.tv by analyzing the sentiment of live text comments made by stream viewers in highly active channels. Automatic sentiment analysis on these comments is a challenging task, as one can compare the language used in Twitch.tv with that used by an audience in a stadium, shouting as loud as possible in sometimes nonorganized ways. This language is very different from common English, mixing Internet slang and gaming-related language with abbreviations, intentional and unintentional grammatical and orthographic mistakes, and emoji-like images called
emotes
. Classic lexicon-based sentiment analysis techniques therefore fail when applied to Twitch comments.

To overcome the challenge posed by the nonstandard language, we propose two unsupervised lexicon-based approaches that make heavy use of the information encoded in emotes, as well as a weakly supervised neural network–based classifier trained on the lexicon-based outputs, which is supposed to help generalization to unknown words by use of domain-specific word embeddings. To enable better understanding of Twitch.tv comments, we analyze a large dataset of comments, uncovering specific properties of their language, and provide a smaller set of comments labeled with sentiment information by crowdsourcing.

We present two case studies showing the effectiveness of our methods in generating sentiment trajectories for events live streamed on Twitch.tv that correlate well with specific topics in the given stream. This allows for a new kind of implicit real-time feedback gathering for Twitch streamers and companies producing games or streaming content on Twitch.

We make our datasets and code publicly available for further research.
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Tactile Working Memory Capacity of Users Who Are Blind in an Electronic Travel Aid Application with a Vibration Belt
Authors: Erp Jan B. F. van , Paul Katja I. , Mioch Tina
Published: May 2020

Electronic travel aids (ETAs) can increase the safety and comfort of pedestrians who have a visual impairment by displaying obstacles through a vibrotactile navigation belt. Building a complete picture of relevant obstacles and finding a safe route requires ETA users to integrate vibrotactile cues over time and space in their tactile working memory. Previous research suggests that the sense of touch exhibits a working memory that has characteristics similar to vision and audition. However, the capacity of the tactile working memory and the effects of secondary tasks are still under-researched. We investigated tactile working memory capacity of 14 adolescent participants who are blind in an immediate, whole report recall test. Participants received trials consisting of one to five vibration patterns presented sequentially at different locations on their torso representing obstacles with a direction (vibration location) and distance (vibration pattern). Recall performance was assessed under four conditions: baseline and with distracting background sounds and/or while walking with the long cane. Both walking and ignoring distracting sounds are relevant for everyday use of an ETA and were expected to decrease memory performance. We calculated the 75% correct scores for two memory performance measures: the number of items in a trial (numerosity), and item location and pattern correct. In the baseline condition, the scores were close to ceiling (i.e., 5 items). However, in the presence of distracting sounds and while walking, the scores were reduced to 3.2 items for numerosity and 1.6 items for location and identity correct. We recommend using 2 items as the maximum tactile working memory load in an applied setting unless users are trained and/or can adopt their strategy without unacceptable costs, such as reducing their walking speed.