bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of Vertical and Lateral Loads Using Strain Gauges: Eliminating the Wheatstone Bridge
Authors: Johnson D. Kody , Rabbi Md. Fazle , Mishra Debakanta , Bruzek Radim
Published: July 2019

Real-time measurement of vertical wheel loads applied to the rail is commonly carried out using strain gauges. One standard approach involves measurement of shear strains at the rail neutral axis, and use of the differential shear concept. Strain gauges are typically mounted on the rail neutral axis between two adjacent ties (over the crib section). A set of four strain measurements (two each, pointed at 45 degrees up and down from the horizontal) are carried out at each end of the crib section, and the measured strains are used to calculate the shear strain magnitudes; this shear strain is in turn used to calculate the applied load. In practice, the four individual strain measurements on each end of the crib (on either face of the rail) are arranged in a single Wheatstone bridge circuit. The purpose for using this common strain measurement configuration lies in the circuits’ ability to eliminate crosstalk, or strain unrelated to the load being measured, e.g. bending strain, or strain due to lateral loading, etc. This paper will propose a new measurement approach whereby eliminating this Wheatstone bridge configuration and measuring eight independent strain signals will enable direct quantification of the vertical as well as lateral load magnitudes. Instead of having to install additional strain gauges on the rail base to measure the lateral loads, the same strain gauges mounted on the rail neutral axis can be used to measure both vertical as well as lateral loads. This proposed technique will simplify the process of vertical and horizontal wheel load detection, and may increase the applicability of these circuits to detect loads in curved sections of track as well as near special track work.
Boundary Conditions Effects on the Crack Growth Mechanism Under Cycling Bending
Authors: Pucillo Giovanni Pio , Esposito Luca , Leonetti Davide
Published: July 2019

The recent increase of train speed and frequency determines a rise of the loads transmitted to the superstructure. Therefore, railway components might experience service loads that have not considered at the design stage. Moreover, wear and backlash modification between components of a mechanical system might be able to modify the internal boundary conditions of the assembly. According to damage tolerance philosophy, an initial flaw is assumed to exist in the fatigue critical location of a structural component, and the analysis of the crack propagation life for such component needs accurate Stress Intensity Factor (SIF) evaluations.

In this study, the effects of the boundary conditions on the crack propagation life have been evaluated for a semi-elliptical surface crack having semi-axes a and c and growing from the root of a shoulder fillet notch in a round bar loaded in bending. Two cases have been analyzed: - the shoulder is free from external forces; - the shoulder is in contact with an adjacent generic body.

At first, the SIF distribution has been calculated with the Virtual Crack Closure Technique, considering or not the nonlinear effect induced by the contact forces arising from the interaction between the shoulder and the neighboring component. Successively, in both the above cases a two-parameters propagation law has been utilized to predict the evolution of both crack shape and crack depth when a cyclic bending load is applied to the rod. For this purpose, different values of the Stress Concentration Factor at the root of the fillet, and of the initial aspect ratio of the crack front, were considered in the calculations.

It is found that the aspect ratio evolves to a unique asymptote, taking or not into account the non-linearity introduced by the contact at the shoulder, and this value depends on the notch severity.

The ratio between the dimensionless SIFs obtained with and without the unilateral constraint at the shoulder, βcs / βfs, does not depend on the relative crack depth and crack shape. Also, the effect of the notch severity on the dimensionless SIF appears to be evident only for the portion of the crack front in the vicinity of the free surface.
Studying the Effect of Tangential Forces on Rolling Contact Fatigue in Rails Considering Microstructure
Authors: Ghodrati Mohamad , Ahmadian Mehdi , Mirzaeifar Reza
Published: July 2019

In this paper, the micro-mechanical mechanisms behind the initiation and propagation of rolling contact fatigue (RCF) damages caused by the large traction forces are investigated. This study provides a three-dimensional (3D) model for studying the rolling contact fatigue in rails. Since rolling contact fatigue is highly dependent on the rail’s steel microstructure behavior, a proper 3D approach to capture the microstructure- and orientation-dependent mechanical behavior is required. A precise material model known as crystal plasticity is used for this purpose. Additionally, a cohesive zone approach is implemented to capture the crack initiation and propagation at the grain boundaries. Using the 3D finite element model which is developed for this study, we evaluate the effect of various parameters such as traction forces along the rail, and also the normal forces on the RCF response. The results reveal that the RCF cracks initiate slightly below the rail surface. These cracks start propagating toward the rail surface when the contact force is applied in repeated load cycles. The results also indicate that the depth at which RCF initiates depends on the ratio between the longitudinal traction forces and the normal loads. With larger traction forces, the cracks initiate closer, or at the rail surface, whereas larger normal loads promote the cracks initiation beneath the surface.
Virginia Tech-Federal Railroad Administration Roller Rig Measurement Capabilities and Baseline Measurements
Authors: Radmehr Ahmad , Tajaddini Ali , Marquis Brian , Ahmadian Mehdi
Published: July 2019

A detailed description of the Virginia Tech-Federal Railroad Administration (VT-FRA) Roller Rig measurement capabilities, along with the efforts in establishing the accuracy, repeatability, and integrity of the results are presented. The results of a series of baseline tests are also documented in an effort to provide an indication of the type of experiments that can be achieved on the rig. The one-fourth scaled rig is intended to be used for evaluating wheel-rail contact mechanics and dynamics with a high degree of precision. The rail is represented by a roller with a diameter that is five times larger than the wheel, in order to maintain the contact ellipse distortion to less than 10 percent. The primary point of differentiation between this rig and others that have been used in the past or are presently in use is that it is able to measure the wheel-rail contact forces with far greater precision than achieved in the past. The rig is also designed such that it provides a high degree of repeatability in testing, often needed for performing design of experiments accurately. The VT-FRA rig is capable of precisely controlling the lateral positioning of the wheel and rail, rail cant angle, the wheel-rail angle of attack, and the speed of the roller and wheel independently. The latter is intended to provide precise control of the relative speed of the wheel and roller, which amounts to precisely controlling creepage. Beyond presenting the rig’s capabilities, the paper provides a discussion of the initial results from the commissioning of the rig. It is concluded that the rig is ready to be commissioned for studies that are of interest to the practitioners in the rail industry and scientists in the research community.
Enhancements in the Performance of Journal Bearing Grease
Authors: Blasko Daniel S. , Aindow David , Mistry Kuldeep K.
Published: July 2019

Wheelsets are removed from service for many reasons by North American Interchange Service. For example, journal bearings can be the cause of wheelset removal when operating temperature or acoustic signatures recorded by wayside detectors exceed certain limits. The Association of American Railroads (AAR) has established 13 failure progression modes to categorize the reason a bearing sets off one of these two detection systems. This study focuses on two failure progression modes: water etch caused by corrosion and issues associated with lubrication (grease).

Greases for rail journal bearings are expected to satisfy a wide variety of requirements such as moisture tolerance, mechanical stability, vibration tolerance, range of operating temperatures and oxidation resistance, to name a few. This paper provides the reader an overview of several experiments and tests that were conducted with the goal of extending service life and reducing corrosion, including field tests used in the development of advanced journal bearing greases for the rail industry. One such new grease formulation was tested in the UK with good results.
Introduction to near-ambient pressure x-ray photoelectron spectroscopy characterization of various materials
Authors: Patel Dhananjay I. , Roychowdhury Tuhin , Jain Varun , Shah Dhruv , Avval Tahereh G. , Chatterjee Shiladitya , Bahr Stephan , Dietrich Paul , Meyer Michael , Thißen Andreas , Linford Matthew R.
Published: July 2019

Near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) is a less traditional form of XPS that allows samples to be analyzed at relatively high pressures, i.e., greater than 2500 Pa. With NAP-XPS, a wide variety of unconventional materials can be analyzed, including moderately volatile liquids, biological samples, porous materials, and/or polymeric materials that outgas significantly. Charge compensation with NAP-XPS takes place simply through the residual/background gas in the chamber, which is ionized by the incident x-rays. High quality spectra—high resolution and good signal-to-noise ratios—are regularly obtained. This article is an introduction to a series of papers in Surface Science Spectra on the NAP-XPS characterization of a series of materials. The purpose of these articles is to introduce and demonstrate the versatility and usefulness of the technique.
Maximal angular correlation in γ – γ coincidences: A quantitative study
Authors: Moura Filipe
Published: July 2019

The measurement of the angular distribution of maximally correlated annihilation gamma rays radiated in coincidence, like those emitted from a 22Na source, is a classic experiment that is nowadays ordinarily performed in nuclear physics laboratory classes. For the first time, we present an analytic expression for such angular distributions, which can be easily tested and compared with the laboratory measurements.
Free fall through the rotating and inhomogeneous Earth
Authors: Isermann Stefan
Published: July 2019

Analytical solutions of the motion through the Earth and suitably shaped gravity tunnels are derived so that inertial forces caused by the Earth's rotation are eliminated and the journey takes place in complete weightlessness. The inhomogeneity of the Earth is represented by the one-dimensional Preliminary Reference Earth Model (PREM). A piecewise linear approximation of the model is used to obtain an analytical solution that corresponds very well to the solution obtained numerically for the PREM.
Banana fungus puts Latin America on alert
Authors: Stokstad Erik
Published: July 2019

Apparent detection of a devastating
Fusarium
strain in Colombia threatens exports.
A painful legacy
Authors: Curry Andrew
Published: July 2019

Mice hint at how people's emotional trauma may affect the biology of their children—and their children's children.
Making precision medicine personal for cystic fibrosis
Authors: Manfredi Candela , Tindall Janice M. , Hong Jeong S. , Sorscher Eric J.
Published: July 2019

Molecular defects in the cystic fibrosis gene prompt creative approaches to treatment
Cortical layer–specific critical dynamics triggering perception
Authors: Marshel James H. , Kim Yoon Seok , Machado Timothy A. , Quirin Sean , Benson Brandon , Kadmon Jonathan , Raja Cephra , Chibukhchyan Adelaida , Ramakrishnan Charu , Inoue Masatoshi , Shane Janelle C. , McKnight Douglas J. , Yoshizawa Susumu , Kato Hideaki E. , Ganguli Surya , Deisseroth Karl
Published: July 2019

Brain circuit visualization and manipulation

How are behaviorally relevant representations of the outside world initiated and manifested in the mammalian brain? Marshel
et al.
combined a channelrhodopsin with an improved holographic stimulation technique to examine activity in the mouse visual cortex, including its deep layers. Optogenetic stimulation of neurons previously activated by natural visual stimuli recreated the original activity and behavior. Neuronal population activity typically propagated from cortical layer 2/3 to layer 5 rather than in the reverse direction. Stimulation of a larger number of cells was required to initiate activity in layer 2/3 than in layer 5. This indicates differences in ensemble coding between the two layers.

Science
, this issue p.
eaaw5202
The ethics of opioids
In Pain: A Bioethicist's Personal Struggle with Opioids
Travis Rieder
HarperCollins, 2019. 314 pp.
Authors: Buchman Daniel Z.
Published: July 2019

A bioethicist's harrowing encounter with prescription painkillers highlights systemic health care problems
The vascular side of Alzheimer's disease
Authors: Liesz Arthur
Published: July 2019

Protein aggregates restrict cerebral blood flow, which causes neural injury
Apollo, in context
Eight Years to the Moon
Nancy Atkinson
Page Street Publishing, 2019. 240 pp.
Shoot for the Moon
James Donovan
Little, Brown, 2019. 464 pp.
Authors: Siddiqi Asif
Published: July 2019

Two tomes paint vivid historical portraits of Apollo 11
A child of Apollo
Authors: Berg Jeremy
Published: July 2019

I was 11 years old when my neighborhood gathered to watch Apollo 11 transport human beings to the surface of the Moon for the first time. We clustered around a black-and-white television when, at dusk in California, Neil Armstrong took his first lunar steps and said, “That's one small step for [a] man, one giant leap for mankind.” This issue of
Science
celebrates the 50th anniversary of this landmark event. The path that led to this success transformed our understanding of humankind's place in the universe and demonstrated the power of an audacious goal in driving technology forward.
Complement-Mediated Neutralization of a Potent Neurotropic Human Pathogen, Chandipura Virus, Is Dependent on C1q
Authors: Kunnakkadan Umerali , Nag Joydeep , Kumar Nisha Asok , Mukesh Reshma Koolaparambil , Suma Sreenath Muraleedharan , Johnson John Bernet
Published: July 2019

Chandipura virus is a clinically important human pathogen of the Indian subcontinent. The rapidity of death associated with CHPV infection in addition to the absence of an effective vaccine or therapeutics results in poor clinical prognosis. The biology of the virus and its interaction with the host immune system, including the complement system, are understudied. Our investigation reveals the susceptibility of CHPV to fluid phase complement and also dissects the pathway involved and the mechanism of virus neutralization. Direct binding of C1q, an important upstream component of the classical pathway of complement to CHPV, and the strong dependency on C1q for virus neutralization highlight the significance of identifying such interactions to better understand CHPV pathogenesis and devise strategies to target this deadly pathogen.
Implementation of a cloud-based referral platform in ophthalmology: making telemedicine services a reality in eye care
Authors: Kern Christoph , Fu Dun Jack , Kortuem Karsten , Huemer Josef , Barker David , Davis Alison , Balaskas Konstantinos , Keane Pearse A , McKinnon Tom , Sim Dawn A
Published: July 2019

Background

Hospital Eye Services (HES) in the UK face an increasing number of optometric referrals driven by progress in retinal imaging. The National Health Service (NHS) published a 10-year strategy (NHS Long-Term Plan) to transform services to meet this challenge. In this study, we implemented a cloud-based referral platform to improve communication between optometrists and ophthalmologists.

Methods

Retrospective cohort study conducted at Moorfields Eye Hospital, Croydon (NHS Foundation Trust, London, UK). Patients classified into the HES referral pathway by contributing optometrists have been included into this study. Main outcome measures was the reduction of unnecessary referrals.

Results

After reviewing the patient’s data in a web-based interface 54 (52%) out of 103 attending patients initially classified into the referral pathway did not need a specialist referral. Fourteen (14%) patients needing urgent treatment were identified. Usability was measured in duration for data input and reviewing which was an average of 9.2 min (median: 5.4; IQR: 3.4–8.7) for optometrists and 3.0 min (median: 3.0; IQR: 1.7–3.9) min for ophthalmologists. A variety of diagnosis was covered by this tool with dry age-related macular degeneration (n=34) being most common.

Conclusion

After implementation more than half of the HES referrals have been avoided. This platform offers a digital-first solution that enables rapid-access eye care for patients in community optometrists, facilitates communication between healthcare providers and may serve as a foundation for implementation of artificial intelligence.
Clinical specialty training in UK undergraduate medical schools: a retrospective observational study
Authors: Vaidya Hrisheekesh J , Emery Alexander W , Alexander Emma C , McDonnell Angus J , Burford Charlotte , Bulsara Max K
Published: July 2019

Objectives

To determine if increased exposure to clinical specialties at medical school is associated with increased interest in pursuing that specialty as a career after foundation training.

Design

A retrospective observational study.

Setting

31 UK medical schools were asked how much time students spend in each of the clinical specialties. We excluded two schools that were solely Graduate Entry, and two schools were excluded for insufficient information.

Main outcome measures

Time spent on clinical placement from UK undergraduate medical schools, and the training destinations of graduates from each school. A general linear model was used to analyse the relationship between the number of weeks spent in a specialty at medical school and the percentage of graduates from that medical school entering each of the Core Training (CT1)/Specialty Training (ST1) specialties directly after Foundation Year 2 (FY2).

Results

Students spend a median of 85 weeks in clinical training. This includes a median of 28 weeks on medical firms, 15 weeks in surgical firms, and 8 weeks in general practice (GP). In general, the number of training posts available in a specialty was proportionate to the number of weeks spent in medical school, with some notable exceptions including GP. Importantly, we found that the number of weeks spent in a specialty at medical school did not predict the percentage of graduates of that school training in that specialty at CT1/ST1 level (ß coefficient=0.061, p=0.228).

Conclusions

This study found that there was no correlation between the percentage of FY2 doctors appointed directly to a CT1/ST1 specialty and the length of time that they would have spent in those specialties at medical school. This suggests that curriculum adjustments focusing solely on length of time spent in a specialty in medical school would be unlikely to solve recruitment gaps in individual specialties.
Optimising pacemaker therapy and medical therapy in pacemaker patients for heart failure: protocol for the OPT-PACE randomised controlled trial
Authors: Paton Maria F , Gierula John , Jamil Haqeel A , Lowry Judith E , Byrom Rowena , Gillott Richard G , Chumun Hemant , Cubbon Richard M , Cairns David A , Stocken Deborah D , Kearney Mark T , Witte Klaus K
Published: July 2019

Introduction

Permanent artificial pacemaker implantation is a safe and effective treatment for bradycardia and is associated with extended longevity and improved quality of life. However, the most common long-term complication of standard pacemaker therapy is pacemaker-associated heart failure. Pacemaker follow-up is potentially an opportunity to screen for heart failure to assess and optimise patient devices and medical therapy.

Methods and analysis

The study is a multicentre, phase-3 randomised trial. The 1200 participants will be people who have a permanent pacemaker for bradycardia for at least 12 months, randomly assigned to undergo a transthoracic echocardiogram with their pacemaker check, thereby tailoring their management directed by left ventricular function or the pacemaker check alone, continuing with routine follow-up. The primary outcome measure is time to all-cause mortality or heart failure hospitalisation. Secondary outcomes include external validation of our risk stratification model to predict onset of heart failure and quality of life assessment.

Ethics and Dissemination

The trial design and protocol have received national ethical approval (12/YH/0487). The results of this randomised trial will be published in international peer-reviewed journals, communicated to healthcare professionals and patient involvement groups and highlighted using social media campaigns.

Trial registration number

NCT01819662.
Observational study to understand interpreter service use in emergency medicine: why the key may lie outside of the initial provider assessment
Authors: Benda Natalie C , Fairbanks Rollin J , Higginbotham D Jeffrey , Lin Li , Bisantz Ann M
Published: July 2019

Objective

To characterise the use of interpreter services and other strategies used to communicate with limited English proficient (LEP) patients throughout their emergency department visit.

Methods

We performed a process tracing study observing LEP patients throughout their stay in the emergency department. A single observer completed 47 hours of observation of 103 communication episodes between staff and nine patients with LEP documenting the strategy used to communicate (eg, professional interpreter, family member, own language skills) and duration of conversations for each communicative encounter with hospital staff members. Data collection occurred in a single emergency department in the eastern USA between July 2017 and February 2018.

Results

The most common strategy (per communicative encounter) was for the emergency department staff to communicate with the patient in English (observed in 29.1% of encounters). Total time spent in communicating was highest using telephone-based interpreters (32.9% of total time spent communicating) and in-person interpreters (29.2% of total time spent communicating). Communicative mechanism also varied by care task/phase of care with the most use of interpreter services or Spanish proficient staff (as primary communicator) occurring during triage (100%) and the initial provider assessment (100%) and the lowest interpreter service use during ongoing evaluation and treatment tasks (24.3%).

Conclusions

Emergency department staff use various mechanisms to communicate with LEP patients throughout their length of stay. Utilisation of interpreter services was poorest during evaluation and treatment tasks, indicating that this area should be a focus for improving communication with LEP patients.
Inequalities in adolescent self-rated health and smoking in Europe: comparing different indicators of socioeconomic status
Authors: Moor Irene , Kuipers Mirte A G , Lorant Vincent , Pförtner Timo-Kolja , Kinnunen Jaana M , Rathmann Katharina , Perelman Julian , Alves Joana , Robert Pierre-Olivier , Rimpelä Arja , Kunst Anton E , Richter Matthias
Published: July 2019

Background

Although there is evidence for socioeconomic inequalities in health and health behaviour in adolescents, different indicators of socioeconomic status (SES) have rarely been compared within one data sample. We examined associations of five SES indicators with self-rated health (SRH) and smoking (ie, a leading cause of health inequalities) in Europe.

Methods

Data of adolescents aged 14–17 years old were obtained from the 2013 SILNE survey (smoking inequalities: learning from natural experiments), carried out in 50 schools in 6 European cities (N=10 900). Capturing subjective perceptions of relative SES and objective measures of education and wealth, we measured adolescents’ own SES (academic performance, pocket money), parental SES (parental educational level) and family SES (Family Affluence Scale, subjective social status (SSS)). Logistic regression models with SRH and smoking as dependent variables included all SES indicators, age and gender.

Results

Correlations between SES indicators were weak to moderate. Low academic performance (OR=1.96, 95% CI 1.53 to 2.51) and low SSS (OR=2.75, 95% CI 2.12 to 3.55) were the strongest indicators of poor SRH after adjusting for other SES-indicators. Results for SSS were consistent across countries, while associations with academic performance varied. Low academic performance (OR=5.71, 95% CI 4.63 to 7.06) and more pocket money (OR=0.21, 95% CI 0.18 to 0.26) were most strongly associated with smoking in all countries.

Conclusions

Socioeconomic inequalities in adolescent health were largest according to SES indicators more closely related to the adolescent’s education as well as the adolescent’s perception of relative family SES, rather than objective indicators of parental education and material family affluence. For future studies on adolescent health inequalities, consideration of adolescent-related SES indicators was recommended.
Development and evaluation of a craniocerebral model with tactile-realistic feature and intracranial pressure for neurosurgical training
Authors: Yi Zongchao , He Bingwei , Liu Yuqing , Huang Shenyue , Hong Wenyao
Published: July 2019

Objective

In this article, a craniocerebral model is introduced for neurosurgical training, which is patient-specific, tactile-realistic, and with adjustable intracranial pressure.

Methods

The patient-specific feature is achieved by modeling from CT scans and magnetic resonance images (MRI). The brain tissue model is built by the hydrogel casting technique, while scalp, skull, vasculature, and lateral ventricles are all-in-one fabricated by three-dimensional (3D) printing. A closed-loop system is integrated to monitor and control the intracranial pressure. 3D measurements, mechanical tests, and simulated external ventricular drain (EVD) placement procedures are conducted on the model.

Results

A neurosurgical training model is completed with high accuracy (mean deviation 0.36 mm). The hydrogel brain tissue has a stiffness more similar to that of a real brain than the common 3D printed materials. The elasticity modulus of hydrogel brain tissue model is E=25.71 kPa, compared with our softest 3D printed material with E=1.14×103 kPa. Ten experienced surgeons rate the tactile realness of the neurosurgical training model at an average point of 4.25 on a scale from 1 (strongly negative) to 5 (strongly positive). The neurosurgical training model is also rated to be realistic in size (4.82), anatomy (4.70), and effective as an aid to improve blind EVD placement skills (4.65).

Conclusions

The neurosurgical training model can provide trainee surgeons with realistic experience in both tactile feedbacks and craniocerebral anatomy, improving their surgical skills.
Limitations of periodical health examinations in detecting occupational chronic solvent encephalopathy
Authors: Furu Heidi M , Sainio Markku , Hyvärinen Hanna-Kaisa , Kaukiainen Ari
Published: July 2019

Objectives

Occupational diseases (ODs) are globally underdetected, and chronic solvent encephalopathy (CSE) is no exception. The aim was to study how the recommended policies and protocols were followed in occupational health services (OHS) periodical health examinations where symptomatic CSE cases have remained undetected.

Methods

We retrospectively studied the medical records of occupational CSE cases (n=18) found in a screening project, which had not been detected in preceding OHS health examinations. We collected data from three sources: OHS units, the screening project and the Finnish Institute of Occupational Health. We analysed the health examinations conducted between symptom onset and the detection of CSE: regularity, content, use of recommended screening tools, exposure estimation and whether a physician was involved in the examinations, as recommended.

Results

The mean duration of symptoms before OD identification was 7.3 years (range 3–13), and 36 health examinations had been conducted. Fifteen workers had attended these (1–9 times each) while suffering from CSE symptoms, and two before symptoms. Only one had not had access to OHS. The recommended symptom screening questionnaire, Euroquest, was used in five (14%) examinations, and previous solvent exposure inquired once. A physician was involved in 24 (67%) examinations, whereas the rest were carried out by a nurse.

Conclusions

Although health examinations are conducted, guidelines are not followed. This may be due to a lack of awareness concerning CSE, and may apply to other ODs. In addition to legislation and policies, OH professionals must be continuously educated to improve awareness, prevention and detection of ODs.
Metabolizable energy values of corn and wheat middlings in broiler chickens
Authors: Dunaway Andrew , Adedokun Sunday A.
Published: July 2019

Two experiments were conducted to evaluate adaptation length (AL) and composition of reference diets on nitrogen (N)-corrected apparent metabolizable energy (AMEn) in 22-d-old broilers. Birds were allocated to nine treatments (n = 6) consisting of wheat – soybean meal (SBM) (reference diet), corn–wheat–SBM, and wheat middlings (WM)–wheat–SBM (exp. 1), or oats–SBM (reference diet), corn–oats–SBM, and WM–oats–SBM (exp. 2) in conjunction with three AL (12, 8, and 4 d) in a factorial arrangement of treatments (3 × 3). Dry matter (DM), N, energy (En) utilization, and AMEn of corn and WM were determined using the difference method. In exp. 1, birds on the WM–wheat–SBM-based diet had the lowest (P < 0.05) DM, N, and En utilization, as well as AMEn compared with the other two diets. Additionally, AMEn for corn was higher (P < 0.05) compared with that of WM. In exp. 2, N utilization in birds on the corn–oats–SBM-based diet was lower (P < 0.05) compared with birds on the oats–SBM-based diet; however, AMEn of corn and WM was not different. In both experiments, AL was not significantly different. Based on these results, the composition of the reference diet could influence AMEn values of corn and WM in 22-d-old broilers.
On restricting to one-loop order the radiative effects in quantum gravity
Authors: Brandt F.T. , Frenkel J. , McKeon D.G.C.
Published: July 2019

The dimensionful nature of the coupling in the Einstein–Hilbert action in four dimensions implies that the theory is non-renormalizable; explicit calculation shows that beginning at two loop order, divergences arise that cannot be removed by renormalization without introducing new terms in the classical action. It has been shown that, by use of a Lagrange multiplier field to ensure that the classical equation of motion is satisfied in the path integral, radiative effects can be restricted to one-loop order. We show that by use of such Lagrange multiplier fields, the Einstein–Hilbert action can be quantized without the occurrence of non-renormalizable divergences. We then apply this mechanism to a model in which there is in addition to the Einstein–Hilbert action, a fully covariant action for a self-interacting scalar field coupled to the metric. It proves possible to restrict loop diagrams involving internal lines involving the metric to one-loop order; diagrams in which the scalar field propagates occur at arbitrary high order in the loop expansion. This model also can be shown to be renormalizable. Incorporating spinor and vector fields in the same way as scalar fields is feasible, and so a fully covariant Standard Model with a dynamical metric field can also be shown to be renormalizable.
Implementation and optimization of the cascade classifier algorithm for UAV detection and tracking
Authors: Martinez Pablo , Barczyk Martin
Published: July 2019

A number of vision-based algorithms designed to detect and track unmanned aerial vehicles (UAVs) from on board a second UAV have been researched, implemented, and experimentally validated over the last decade. However, the successful methods have tended to rely on characteristics such as color or shape, meaning they require the target UAV to have particular markings or geometries. This paper uses the Viola–Jones cascade classifier, a computer vision algorithm originally designed to detect human faces in video streams, and demonstrates its capability for detecting and tracking an arbitrary type of UAV with excellent performance in either indoor or outdoor environments and with a variety of backgrounds. The Viola–Jones algorithm is applied to two specific quadrotor UAV models, the Solo from 3D Robotics and the AR.Drone 2.0 from Parrot. Experimental testing demonstrates that the resulting system achieves very good detection and tracking performance in real time on each UAV type for both indoor and outdoor flight tests.
String analog of Reissner–Nordström black holes cannot be overcharged
Authors: Düztaş Koray , Jamil Mubasher
Published: July 2019

In this work, we attempt to overcharge extremal and nearly extremal charged black holes in string theory, known as the Garfinkle–Horowitz–Strominger solution. We first show that extremal black holes cannot be overcharged analogous to the case of Reissner–Nordström (RN) black holes. Contrary to their analog in general relativity, nearly extremal black holes can neither be overcharged beyond extremality, nor can they be driven to extremality by the interaction with test particles. Therefore, the analysis in this work also implies that the third law of black hole thermodynamics holds for the relevant charged black holes in string theory perturbed by test particles. This can be interpreted as a stronger version of the third law since one can drop out the continuity proviso for the relevant process.
Mean curvature flow in Fuchsian manifolds
Authors: Huang Zheng , Lin Longzhi , Zhang Zhou
Published: July 2019

Motivated by the goal of detecting minimal surfaces in hyperbolic manifolds, we study geometric flows in complete hyperbolic [Formula: see text]-manifolds. In general, the flows might develop singularities at some finite time. In this paper, we investigate the mean curvature flow in a class of complete hyperbolic [Formula: see text]-manifolds (Fuchsian manifolds) which are warped products of a closed surface of genus at least two and [Formula: see text]. We show that for a large class of closed initial surfaces, which are graphs over the totally geodesic surface [Formula: see text], the mean curvature flow exists for all time and converges to [Formula: see text]. This is among the first examples of converging mean curvature flows starting from closed hypersurfaces in Riemannian manifolds. We also provide calculations for the general warped product setting which will be useful for further works.
Skew-symmetric tensor decomposition
Authors: Arrondo Enrique , Bernardi Alessandra , Marques Pedro Macias , Mourrain Bernard
Published: July 2019

We introduce the “skew apolarity lemma” and we use it to give algorithms for the skew-symmetric rank and the decompositions of tensors in [Formula: see text] with [Formula: see text] and [Formula: see text]. New algorithms to compute the rank and a minimal decomposition of a tritensor are also presented.
Associate class graph of zero-divisors of a commutative ring
Authors: Tang Gaohua , Lin Guangke , Wu Yansheng
Published: July 2019

In this paper, we introduce the concept of the associate class graph of zero-divisors of a commutative ring [Formula: see text], denoted by [Formula: see text]. Some properties of [Formula: see text], including the diameter, the connectivity and the girth are investigated. Utilizing this graph, we present a new class of counterexamples of Beck’s conjecture on the chromatic number of the zero-divisor graph of a commutative ring.
Some properties of Padovan quaternion
Authors: Gunay Hasan , Taskara Necati
Published: July 2019

In this study, we consider the Padovan Quaternions. Then we investigate the some new properties such as the summation formulas and binomial sum for these quaternions.
Progress and Prospects of China in Implementing the Goal 14 of the 2030 Agenda for Sustainable Development
Authors: CUI Feng , SHEN Bin
Published: July 2019

Following the entry into force of the 2030 Agenda for Sustainable Development, China has rapidly established key areas and priorities for its implementation, and Goal 14 focusing on sustainable marine development (hereinafter referred to as “SDG 14”) has been attached with great importance. This paper illustrates China’s implementation of SDG14 from four aspects: marine pollution control, conservation of marine environment, sustainable utilization of marine resources and international cooperation in global governance, and concludes that SDG14 has been implemented well on the whole in China. On this basis, the paper looks to the future sustainable development of ocean in China, and suggests improving the legal system, strengthening marine environmental monitoring, and advancing international cooperation for ocean sustainable development.
Current status of international medical education in China: A cross-sectional study
Authors: Chu Yu-Xia , Gao Ming , Gao Hai-Feng , Liu Ye , Cheng Xun-Jia , Qian Rui-Zhe , Zhou Xiang-Feng , Feng Yi
Published: July 2019

Objective: This study aims to understand the current learning state, curriculum evaluation, and career planning of international Bachelor of Medicine, Bachelor of Surgery (MBBS) students in China in order to support educators and policy makers in developing interventions to support international MBBS students.

Methods: A cross-sectional survey was conducted at Fudan University from March 2017 to May 2018. A self-administered questionnaire regarding medical teaching and evaluation methods and recommendations was used to collect the data from international MBBS students ([Formula: see text]) and native Chinese medical students ([Formula: see text]) currently at the school as well as teachers directly involved in teaching activities with these students ([Formula: see text]). Data were analyzed using GraphPad Prism 6, and all results are presented as frequencies (percentages).

Results: Most of the international MBBS students had never studied at a university before (76%). The first and second most common reasons for choosing the MBBS program were an interest in medical science (79%) and relieving patients’ sufferings and realizing self-value (61%). The learning motivation of international MBBS students came mainly from the interests in medicine (90%). A total of 74% of international MBBS students considered the course setting to be appropriate or neutral. The top biggest problem in clinical practice reported by international MBBS students was communication barriers caused by the lack of language proficiency. The first choice of future work after graduation for international MBBS students was studying or working abroad. The top two recommendations among teachers for improving academic achievement were providing textbooks in students’ native languages (64%) and reading more medical books (47%).

Conclusions: International MBBS students generally thought that the course setting was rational, and were mostly satisfied with the international MBBS program. The use of textbooks in the international MBBS students’ native languages was reported to be helpful for improving these students’ academic achievements.
Effect of Nonparallel End Face on Energy Dissipation Analyses of Rocklike Materials Based on SHPB Tests
Authors: Yuan Pu , Wei Ning-Ning , Ma Qin-Yong
Published: July 2019

To evaluate the effect of nonparallel end face of rocklike specimens in SHPB tests, the characteristics of energy dissipation are analyzed based on numerical simulations for end‐face nonparallelism from 0% to 0.40% and Young’s modulus from 14 GPa to 42 GPa. With the increment of end‐face nonparallelism, both energy consumption density and dissipated energy density show a slight increase trend, while releasable elastic strain energy density presents a slight decrease trend. Existence of elastic unloading in the damaged rocklike specimen leads to a reduction of energy consumption density and a constant dissipated energy density during total strain shrinkage. At peak dynamic stress, dissipated energy density presents a linear upward trend with the increment of end‐face nonparallelism and Young’s modulus, while releasable elastic strain energy density shows an inverse trend. A binary linear regression equation is deduced to estimate the energy dissipation ratio. Mechanical damage evolution of the rocklike specimen is divided into two regions in line with the two regions in dynamic stress‐strain curves, and the transition between the slow‐growth region and rapid‐growth region is shifted to the right with the increment of end‐face nonparallelism. Due to the presence of nonparallel end face, fluctuation presents in energy density evolution and mechanical damage evolution. The fluctuation is enhanced with the increment of end‐face nonparallelism and weakened with the increase of Young’s modulus. Based on energy density evolution and mechanical damage evolution analyses, the maximum end‐face nonparallelism should be controlled within 0.20%, twice the value in ISRM suggested methods, which reduces the cost and time for processing rocklike specimens.
Antioxidant and Glycemic Regulatory Properties Potential of Different Maturity Stages of Leaf of Ceylon Cinnamon (Cinnamomum zeylanicum Blume) In Vitro
Authors: Mendis Abeysekera Walimuni Prabhashini Kaushalya , Arachchige Sirimal Premakumara Galbada , Abeysekera Walimuni Kanchana Subhashini Mendis , Ratnasooriya Wanigasekera Daya , Indeewari Medawatta Hela Medawattegedara Upeksha
Published: July 2019

Dichloromethane:methanol (1:1, v/v) extracts of different maturity stages (immature, partly mature, and mature) of authenticated leaves of Ceylon cinnamon (CC) were used in this study. Antioxidant properties [total polyphenolic content (TPC) and total flavonoid content (TFC), 1, 1-diphenyl-2-picryl-hydrazyl (DPPH), 2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS)), oxygen radical absorbance capacity (ORAC), and ferric reducing antioxidant power (FRAP)] and glycemic regulatory properties [antiamylase (AA); antiglucosidase (AG)] were evaluated using 96-well microplate based bio assays in vitro (TPC, TFC, DPPH, ABTS, ORAC n=4 each; FRAP, AA, AG n=3 each). Results clearly revealed significant differences (p<0.05) among different maturity stages of leaf of CC for both antioxidant and glycemic regulatory properties (except AG activity). The mean antioxidant and glycemic regulatory activities of immature, partly mature, and mature leaves ranged from TPC: 0.68 ± 0.02–22.35 ± 0.21 mg gallic acid equivalents/g of sample (GS); TFC: 0.85 ± 0.01–4.68 ± 0.06 mg quercetin equivalents/GS; DPPH: 0.42 ± 0.01–27.09 ± 0.65 mg Trolox equivalents (TE)/GS; ABTS: 3.57 ± 0.10–43.91 ± 1.46 TE/GS; ORAC: 0.71 ± 0.01–18.70 ± 0.26 TE/G, FRAP: 0.31 ± 0.02–69.16 ± 0.52 TE/GS; and AA: 18.05 ± 0.24–36.62 ± 4.00% inhibition at 2.5 mg/mL. Mature leaf had the highest antioxidant and AA activities for all the assays investigated. In contrast, immature leaf had the lowest. The order of potency for antioxidant and AA activities was mature leaf > partly mature leaf > immature leaf. This is the first study to report on antioxidant and glycemic regulatory properties of different maturity stages of leaf of Ceylon cinnamon and highlights its potential use in management of oxidative stress-associated chronic diseases including diabetes mellitus.
Modification of Vertical Earth Pressure Formulas for High Fill Cut‐and‐Cover Tunnels Using Experimental and Numerical Methods
Authors: Li Sheng , Ma Li , Ho I-Hsuan , Wang Qicai , Yu Bentian , Zhou Peng
Published: July 2019

The high‐filled cut‐and‐cover tunnel (HFCCT) is a solution to reclaim more useable lands due to the unique landforms of Loess Plateau in northwestern China. Because of the ultrahigh backfill, the estimation of vertical earth pressure will significantly affect the design and safety of the cut‐and‐cover tunnel (CCT). The current methods for estimating the vertical earth pressure are either to overestimate or underestimate the vertical earth pressure on the top of HFCCT. To more precisely estimate the vertical earth pressure distribution, the vertical earth pressure based on the soil column pressure, γh (h: the height of backfill above the CCT), needs to be properly modified. Considering different influential factors, four corresponding coefficients are proposed: k0: cross‐sectional shape of CCT effect, k1: stiffness of backfill effect, k2: width of CCT effect, and k3: coupling effect of slope angle, θ, and the ratio of B/D. It is found that k0 has little influence; the k3 and k1 reduce and k2 amplifies the γh. The corresponding general forms for these coefficients are determined based on finite element analysis results. A general equation for estimating vertical earth pressure for the HFCCT including these four coefficients is proposed. Meanwhile, this general form is verified by the numerical analysis results and experimental results for different cases. Therefore, this proposed equation is applicable to estimate the vertical earth pressure for existing or newly designed HFCCT. Furthermore, this proposed method can significantly reduce the computational work in engineering analysis.
Midlife Forgetfulness and Risk of Dementia in Old Age: Results from the Danish Working Environment Cohort Study
Authors: Ishtiak-Ahmed Kazi , Hansen Åse Marie , Mortensen Erik Lykke , Garde Anne Helene , Brødsgaard Grynderup Matias , Gyntelberg Finn , Islamoska Sabrina , Lund Rikke , Phung Thien Kieu Thi , Prescott Eva , Waldemar Gunhild , Nabe-Nielsen Kirsten
Published: July 2019

Background: Despite the current evidence of a high prevalence of forgetfulness in middle-aged individuals, and the evidence of a link between midlife memory complaints and biological changes in the brain, no previous study has yet investigated midlife forgetfulness in relation to risk of dementia in old age. Aims: We investigated whether midlife forgetfulness was an indicator of an increased risk of dementia in old age. Methods: We used data from 3,136 employed men and women who participated in the Danish Work Environment Cohort Study in 1990. These data were linked to Danish national registers. Participants were asked whether their closest relative had ever told them that they were forgetful. Incidence rate ratios (IRR) were estimated using Poisson regression analysis. Results: At baseline, 749 (24%) study participants were categorized as forgetful, and 86 (2.7%) participants were diagnosed with dementia during a total of 31,724 person-years at risk. After adjusting for sociodemographic factors, comorbidities, and work-related factors, midlife forgetfulness was associated with a higher risk of dementia (IRR = 1.82; 95% CI: 1.12–2.97). Conclusions: This study is the first to investigate midlife forgetfulness and dementia, and the results suggest that midlife forgetfulness is an early indicator of an increased risk of dementia in old age.