bluuebunny/crossref_metadata_2025 huggingface dataset:
Critical Load of Columns of Varying Cross Section
Authors: Thomson W. T.
Published: April 2021

A method is developed for determining the critical load of a pin-ended long column of n different cross sections and lengths. For n less than 5, the method results in a simple equation for the critical load. Specific examples for columns of 2, 3, and 4 sections are given, and experimental data are presented for comparison.
A Quantitative Comparison of Flow and Deformation Theories of Plasticity
Authors: Hodge P. G. , White G. N.
Published: April 2021

The stresses and displacements in a partly plastic, infinitely long, hollow cylinder are obtained according to the flow type of stress-strain law of Prandtl-Reuss and to the deformation law of Hencky. In both cases the Mises yield condition is used and the compressibility of the material is taken into account. It is shown that under these assumptions the two theories yield substantially the same results for this particular problem, but that one theory or the other may be preferable for computing purposes in certain cases. The results are compared with those of other investigations in which different combinations of stress-strain law, yield condition, compressibility, and end loading were assumed.
An Investigation of Ejector Design by Analysis and Experiment
Authors: Keenan J. H. , Neumann E. P. , Lustwerk F.
Published: April 2021

A one-dimensional method of analysis of jet pumps or ejectors is presented. The analysis considers mixing of the primary and secondary streams at constant pressure, and mixing of the streams at constant area. For the analytical conditions considered, better performance can be obtained when constant-pressure mixing is employed. A comparison between experimental and analytical results shows good agreement over a broad range of variables. Some experimental data on the length of tube required for mixing of the two streams are presented. A method for jet-pump design is given.
Stability of Flow in a Rocket Motor
Authors: Gunder D. F. , Friant D. R.
Published: April 2021

This paper presents an analytical treatment leading to a criterion for the proper design of liquid rocket motors to insure freedom from the phenomenon of “chugging” without unnecessary increase in fuel-tank or fuel-pump pressures. The most successful of the several methods suggested here is that of Nyquist, which involves a simple conformal transformation. The analytical treatment presented in this paper has been applied successfully in practice to eliminate this type of instability.
Effect of Stress-Free Edges in Plane Shear of a Flat Body
Authors: Read W. T.
Published: April 2021

This paper determines the tangential stiffness of a flat rectangular body, or shear pad, with a uniform relative tangential displacement on the upper and lower surfaces. The state of stress differs from pure shear in that the edges are stress-free. The correction to the stiffness in pure shear is obtained as a function of Poisson’s ratio and the length-to-thickness ratio. The paper also illustrates the power of energy methods in furnishing accurate approximations with a small amount of numerical work when only over-all quantities, such as stiffness, are investigated. By manipulating energy relations and using the Prager-Synge approximate method a few hours of slide-rule computation was sufficient to determine both upper and lower bounds for the stiffness.
Vibrations of Elastic Systems Having Hereditary Characteristics
Authors: Volterra Enrico
Published: April 2021

Results of experiments carried out on plastics and rubberlike materials at high rate of straining are given. It is shown that the dynamic stress-strain (σ, ϵ) relationship for those materials can be expressed by the formula σ = f ( ϵ ) + ∫ 0 t ϕ ( t - τ ) d ϵ ( τ ) d τ d τ The first term represents the static stress-strain relationship, while the second depends on the rate of straining de dt . As a first approximation it is supposed that the materials follow Hooke’s law when statically stressed. Equation [1] then becomes σ = E ϵ + ∫ 0 t ϕ ( t - τ ) d ϵ ( τ ) d τ d τ Materials which follow the second equation are called materials with “hereditary characteristics.” Vibrations of single-degree-of-freedom systems having hereditary characteristics are considered. Methods of finding the hereditary function ϕ(t) from forced vibrations are given. Free and forced vibrations of simply supported beams having hereditary characteristics are studied.
Torsional Stress Concentration in Angle and Square Tube Fillets
Authors: Huth J. H.
Published: April 2021

This paper points out the wide variation in the results of previous investigations into the stress concentration at the fillets of angle sections subjected to uniform torsion. The relaxation method is applied and new results are given (not in agreement with previous results) for both angle sections and thin-walled square tube sections. These results are believed to be within about 4 per cent of the correct values, and they cover a complete range of fillets of all sizes. Also, the maximum shearing stress and torsional rigidity are given for a prismatical bar whose cross section is formed by a circular quadrant tangent to two sides of a square. It is pointed out that the stress concentration in angle sections with generous fillets may be lowered considerably by rounding off the outside corner in such a way as to keep the thickness of the section everywhere approximately constant.
Momentum and Mass Transfer in Coaxial Gas Jets
Authors: Forstall Walton , Shapiro Ascher H.
Published: April 2021

The mixing at constant pressure of a circular jet with an annular coaxial stream has been studied for conditions of nearly common density and temperature, but differing initial velocities. By using 10 per cent by volume of helium as a tracer in the inner stream, the mixing region was mapped with respect to both material and momentum transfer. It is concluded that material diffuses more rapidly than momentum; that the principal independent variable determining the shape of the mixing region is the velocity ratio of the streams; and that the integral method of Squire and Trouncer, using experimentally determined constants, is adequate for predicting approximate values of concentration and velocity in the mixing region of a jet flowing into a moving medium of the same density. Data for widely different experiments of various investigators show that the turbulent Prandtl and the Schmidt numbers are both within ±10 per cent of 0.70, independent of the nature of the experiment and the magnitudes of the laminar Prandtl and Schmidt numbers.
The Design of Resonant Quartz-Crystal Ultrasonic Transducers for Research Purposes
Authors: Swanson G. W. , Thomson W. T.
Published: April 2021

Ultrasonic waves have become an important research technique in many fields, including chemistry, mechanics, and others. Piezoelectric crystals excited by a source of alternating voltage are commonly used as a method of producing ultrasonic mechanical vibrations for such purposes. Hence it is often necessary that crystal transducers be designed, and to those unfamiliar with the theory of piezoelectricity, such a design problem may entail time-consuming research. The present paper is intended to co-ordinate the several approaches to the design problem and to present a practical method for designing quartz-crystal transducers for ultrasonic frequencies.
Optimization of the Nodalization of Nuclear System Thermal-Hydraulic Code Applied on Primary Loop Benchmark
Authors: Xu Hong , Badea Aurelian Florin , Cheng Xu
Published: April 2021

In best estimate plus uncertainty approach for thermal-hydraulic simulation in nuclear engineering, a crucial step for the qualification of the scenario simulation is the discretization, i.e., the nodalization of nuclear power plants and related integral test facilities (ITFs). Since intermediate break loss-of-coolant accident (IBLOCA) simulation is getting more and more attention in this decade, we focused on the nodalization of an IBLOCA scenario—a primary loop (PKL) I2.2 benchmark delivered by the organization for economic cooperation and development PKL4-project—using the analyses of thermal-hydraulics for leaks and transients (ATHLET) code. This work followed mainly the nodalization methodology of Petruzzi and D'Auria, including both qualitative and quantitative criteria, being divided into three phases for component volume, steady-state, and transient, respectively. The authors used also some specific approaches: (1) for component volume qualification, a volume fractional parameter was introduced, considering not only the relative error of each component but also the volume fraction in the whole system (an 0.2% acceptability level was chosen for this parameter); (2) the experimental data were not used directly as a reference within the nodalization procedure but the calculated results delivered by the most refined nodalization. Based on the estimator of average amplitude in the fast Fourier transform-based method (FFTBM), the convergence, rationality, and an optimized result of nodalization in the simulation of an actual IBLOCA transient benchmark have been judged. After three phases of nodalization qualification, it has been proved that the final nodalization has the necessary degree of convergence for a good reproduction of the benchmark geometry, allowing the proper simulation of involved phenomena. Finally, a middle-refined nodalization was found as being optimal, fulfilling the convergence criteria with a reasonable central processing unit time consumption. The nodalization scheme in this work was not seen as being the single factor influencing the simulated results, but just as a prerequisite to allow further reliable improvements on the models used by ATHLET (aspects not referred to in this particular study). Therefore, the simulated results presented here will match the experimental ones only as general trends; improvements may be further achieved by using new and more precise models (e.g., for critical mass flow, heat transfer, countercurrent flow, etc.) in the system thermal-hydraulic code.
Prediction of Structural Reliability Through an Alternative Variability-Based Methodology
Authors: Haas Kyle
Published: April 2021

The often-competing goals of optimization and reliability design amplify the importance of verification, validation, and uncertainty quantification (VVUQ) to achieve sufficient reliability. Evaluation of a system's reliability presents practical challenges given the large number of permutations of conditions that may exist over the system's operational lifecycle. Uncertainty and variability sources are not always well defined and are sometimes not possible to predict, yielding traditional uncertainty quantification (UQ) techniques insufficient. A variability-based method is proposed to bridge this gap in state-of-the-art UQ practice where sources of uncertainty and variability cannot be readily quantified. At the point of incipient structural failure, the structural response becomes highly variable and sensitive to minor perturbations in conditions. This characteristic provides a powerful opportunity to determine the critical failure conditions and to assess the resulting structural reliability through an alternative variability-based method. Nonhierarchical clustering, proximity analysis, and the use of stability indicators are combined to identify the loci of conditions that lead to a rapid evolution of the response toward a failure condition. The method's utility is demonstrated through its application to a simple nonlinear dynamic single-degree-of-freedom structural model. In addition to the L2 norm, a new stability indicator is proposed called the “instability index,” which is a function of both the L2 norm and the calculated proximity to adjacent loci of conditions with differing structural response. The instability index provides a rapidly achieved quantitative measure of the relative stability of the system for all possible loci of conditions.
Quantitative depth profiling of Al in SiC using time of flight–secondary ion mass spectroscopy
Authors: Smentkowski Vincent S. , Goswami Shubhodeep
Published: April 2021

Historically, dynamic secondary ion mass spectroscopy (D-SIMS) has been used to quantitatively monitor the depth distribution of species present in low concentrations in samples/devices. We are not aware of any manuscript that describes the use of time of flight–secondary ion mass spectroscopy (ToF-SIMS) to perform quantitative analysis of aluminum present at low concentrations in silicon carbide (SiC) wafer substrates. In this paper, we will show that ToF-SIMS is able to replicate D-SIMS analysis. However, analysis at the lowest concentrations requires the collection of more spectral images at each depth. Tables of sputtering rates and sputtering yields, in addition to relative sensitivity factors are provided. We also highlight the benefits of ToF-SIMS analysis.
Validity of Two Wheelchair-Mounted Devices for Estimating Wheelchair Speed and Distance Traveled
Authors: Karinharju Kati S. , Gomersall Sjaan R. , Clanchy Kelly M. , Trost Stewart G. , Yeo Li T. , Tweedy Sean M.
Published: April 2021

This study evaluated the validity of two wheelchair-mounted devices—the Cateye® and Wheeler—for monitoring wheelchair speed and distance traveled. Speed estimates were validated against a calibrated treadmill at speeds from 1.5 to 10 km/hr. Twenty-five wheelchair users completed a course of known distance comprising a sequence of everyday wheelchair activities. Speed estimate validity was very good (mean absolute percentage error ≤ 5%) for the Wheeleri at all speeds and for the Cateye at speeds >3 km/hr but not speeds <3 km/hr (mean absolute percentage error > 20%). Wheeleri distance estimates were good (mean absolute percentage error < 10%) for linear pushing activities and general maneuvering but poor for confined-space maneuvering. Cateye estimates were good for continuous linear propulsion but poor for discontinuous pushing and maneuvering (both general and confined space). Both devices provided valid estimates of speed and distance for typical wheelchair-based exercise activities. However, the Wheeleri provided more accurate estimates of speed and distance during typical everyday wheelchair activities.
Nitrate-Responsive Suppression of Dimethyl Sulfoxide Respiration in a Facultative Anaerobic Haloarchaeon, Haloferax volcanii
Authors: Koyanagi Isamu , Dohra Hideo , Fujiwara Taketomo
Published: April 2021

Haloferax volcanii
can grow anaerobically by denitrification (nitrate respiration) or DMSO respiration. In facultative anaerobic bacteria that can grow by both nitrate respiration and DMSO respiration, nitrate respiration is preferentially induced when both nitrate and DMSO are available as the respiratory substrates.
The Combination of Venetoclax and Ixazomib Selectively and Efficiently Kills HIV-Infected Cell Lines but Has Unacceptable Toxicity in Primary Cell Models
Authors: Alto Alecia , Natesampillai Sekar , Chandrasekar Aswath P. , Krogman Ashton , Misra Anisha , Shweta FNU , VanLith Caitlin , Yao Joseph D. , Cummins Nathan W. , Badley Andrew D.
Published: April 2021

A cure for HIV would require eliminating cells that contain the virus in a latent form from the body. Current antiretroviral medications are unable to rid the body of latently infected cells. Here, we show that a combination of investigational agents—ixazomib plus venetoclax—which reactivate latent virus and predispose infected cells to apoptosis may reduce latent virus in a T cell model, but at the expense of nonspecific toxicity in primary cells.
Human Cytomegalovirus miR-US25-1 Targets the GTPase RhoA To Inhibit CD34
+
Hematopoietic Progenitor Cell Proliferation To Maintain the Latent Viral Genome
Authors: Diggins Nicole L. , Crawford Lindsey B. , Hancock Meaghan H. , Mitchell Jennifer , Nelson Jay A.
Published: April 2021

Each herpesvirus family establishes latency in a unique cell type. Since herpesviruses genomes are maintained as episomes, the viruses need to devise mechanisms to retain the latent genome during cell division.
BEExact: a Metataxonomic Database Tool for High-Resolution Inference of Bee-Associated Microbial Communities
Authors: Daisley Brendan A. , Reid Gregor
Published: April 2021

The failure of current universal taxonomic databases to support the rapidly expanding field of bee microbiota research has led to many investigators relying on “in-house” reference sets or manual classification of sequence reads (usually based on BLAST searches), often with vague identity thresholds and subjective taxonomy choices. This time expensive, error- and bias-prone process lacks standardization, cripples the potential for comparative cross-study analysis, and in many cases is likely to sway study conclusions.
The Gut Microbiome in Autism: Study-Site Effects and Longitudinal Analysis of Behavior Change
Authors: Fouquier Jennifer , Moreno Huizar Nancy , Donnelly Jody , Glickman Cody , Kang Dae-Wook , Maldonado Juan , Jones Rachel A. , Johnson Kimberly , Adams James B. , Krajmalnik-Brown Rosa , Lozupone Catherine
Published: April 2021

Autism spectrum disorder (ASD) is a brain developmental disorder with varying behavioral symptom severity both across individuals and within individuals over time. There have been promising but also inconsistent literature results regarding how the gut microbiota (microbiome) may be involved.
Postvolcanic Aerosols: Measurements of Altitude and Particle Sizes with Twilight-Sky Polarimetry
Authors: Ugolnikov O. S. , Maslov I. A.
Published: April 2021

The intensity and polarization of the twilight-sky background were measured during the epoch of “purple lights” after the Raikoke volcanic eruption in the summer of 2019. The increase in brightness paired with the decrease in polarization was registered, and the changes were especially noticeable in the dusk segment. The altitude distribution of aerosol particles and their mean size were found with previously developed techniques. The median radius of the lognormal distribution (0.11 μm) is typical of the background conditions or weak eruptions; however, the aerosols were mostly concentrated in the upper troposphere and near the tropopause rather than in the stratosphere. From comparison with satellite data obtained almost a decade ago after similar eruptions (like those of the Kasatochi volcano and others), it has been shown that the properties of their aerosols are similar, which confirms that the purple light phenomenon observed in 2019 was of volcanic origin.
Detection and Neutralization of Unsymmetrical Dimethylhydrazine on the Surface of Construction Materials
Authors: Polunin K. E. , Ul’yanov A. V. , Polunina I. A. , Buryak A. K.
Published: April 2021

The construction materials that contacted with unsymmetrical dimethylhydrazine and the desorption solutions obtained when treating the contaminated surface of metals and alloys with water and reagents were studied by chromatography and mass spectrometry. Neutralization of unsymmetrical dimethylhydrazine was studied using ozone and shungite. Ozonation makes it possible to destroy the toxicant molecules chemically and physically adsorbed on the surface of metal constructions, due to which they can be reused and utilized. Shungite effectively adsorbs and catalytically decomposes not only unsymmetrical dimethylhydrazine and its transformation products, but also oligomer compounds formed during the storage of hydrazine fuel. Ozonation of spent shungite can increase the efficiency of destructive processes and completeness of its regeneration.
Longitudinal analyses of gender differences in first authorship publications related to COVID-19
Authors: Lerchenmüller Carolin , Schmallenbach Leo , Jena Anupam B , Lerchenmueller Marc J
Published: April 2021

Objective

Concerns have been raised that the COVID-19 pandemic has shifted research productivity to the disadvantage of women in academia, particularly in early career stages. In this study, we aimed to assess the pandemic’s effect on women’s COVID-19-related publishing over the first year of the pandemic.

Methods and results

We compared the gender distribution of first authorships for 42 898 publications on COVID-19 from 1 February 2020 to 31 January 2021 to 483 232 publications appearing in the same journals during the same period the year prior. We found that the gender gap—the percentage of articles on which men versus women were first authors—widened by 14 percentage points during the COVID-19 pandemic, despite many pertinent research fields showing near equal proportions of men and women first authors publishing in the same fields before the pandemic. Longitudinal analyses revealed that the significant initial expansions of the gender gap began to trend backwards to expected values over time in many fields. As women may have been differentially affected depending on their geography, we also assessed the gender distribution of first authorships grouped by countries and geographical areas. While we observed a significant reduction of the shares of women first authors in almost all countries, longitudinal analyses confirmed a resolving trend over time.

Conclusion

The reduction in women’s COVID-19-related research output appears particularly concerning as many disciplines informing the response to the pandemic had near equal gender shares of first authorship in the year prior to the pandemic. The acute productivity drain with the onset of the pandemic magnifies deep-rooted obstacles on the way to gender equity in scientific contribution.
Vibro-fluidization of sand under coupled static loading and high-frequency cyclic loading
Authors: Dai Ning , Shan Yao , Fu Longlong , Ye Weitao , Guo Peijun , Zhou Shunhua , Rackwitz Frank , Stolle Dieter
Published: April 2021

An increase in the operation speed of high-speed trains often leads to an increase in the loading frequency on subgrade soil. Hence, the long-term dynamic behavior of the subgrade and the service performance of high-speed tracks are affected. To determine the stress–strain characteristics of granular soil under high-frequency loading, a triaxial test setup was modified to investigate the effects of loading acceleration and duration, water content, vibration frequency, cell pressure, and initial soil density. The experimental results indicate that there are reductions in axial stress and volumetric strain during high-frequency loading. The reduction in axial stress is as high as 40%, and that of volumetric strain, which is permanent, could approach 0.1%. The stress reduction, strain compression, and excess pore pressure are found to vary linearly with vibration acceleration when a/g > 0.02, where a is vertical vibration acceleration and g is gravitational acceleration. The reduction in strength and strains are found to depend on the loading acceleration and effective cell pressure, but independent of the loading duration, water content, frequency, and initial density. A threshold acceleration a = 0.02g is observed, below which the changes in the shear strength and volumetric strain induced by vibration are negligible. At high vibration acceleration, the strain amplitude could increase, eventually leading to a collapse of the specimen.
EVALUATING THE IMPACT OF SANITARY AND PHYTOSANITARY MEASURES ON AGRICULTURAL TRADE: EVIDENCE FROM THAI FRUIT EXPORTS TO CHINA
Authors: WONGMONTA SASIWOOTH
Published: April 2021

Food safety concerns have become increasingly important challenge for agricultural trade. Sanitary and phytosanitary (SPS) measures are often considered as major non-tariff trade barriers, which have surged rapidly over the recent decade. This study systematically investigates the impact of China’s SPS measures on Thai fruit exports. The panel dataset is constructed with 17 Thai fruit items for the sample period 2000–2018. Gravity equations are estimated to quantify the trade effects of SPS measures on the value of fruit exports from Thailand to China. The results from the sectoral analysis reveal that the restrictiveness of SPS measures has a positive and substantial effect on export volumes. This suggests that non-arbitrary and informative SPS requirements imposed by a large importing country would help facilitate the agricultural trade.
Analytical soliton solutions and modulation instability for a generalized (3 + 1)-dimensional coupled variable-coefficient nonlinear Schrödinger equations in nonlinear optics
Authors: Hamed A. A. , Shamseldeen S. , Abdel Latif M. S. , Nour H. M.
Published: April 2021

In this work, the soliton solutions of a (3 + 1)-dimensional coupled nonlinear Schrödinger system with time-dependent coefficients arising in optical fiber has been studied analytically. A complex traveling wave ansatz is used to transform the proposed coupled partial differential equations into ordinary differential equations (ODEs). Then, we solved the obtained nonlinear ODEs for the envelope function in the traveling wave parameter. The obtained waves envelope have the forms of bright and dark soliton-like solutions which are considered as new solutions of the studied system. As a kind of completing the analysis, the modulation instability is discussed based on the linear stability analysis.
Nonlinear dynamical wave structures to the Date–Jimbo–Kashiwara–Miwa equation and its modulation instability analysis
Authors: Younis M. , Seadawy A. R. , Bilal M. , Rizvi S. T. R. , Althobaiti Saad , Alkafafy Mohamed
Published: April 2021

A particular attention is paid to the nonlinear dynamical exact wave solutions to the (2 + 1)-dimensional Date–Jimbo–Kashiwara–Miwa equation (DJKME). A variety of solutions are extracted in different shapes like dark, singular, dark-singular by implementing [Formula: see text]-expansion function method and modified direct algebraic method. In addition, we also secure singular periodic and plane wave solutions with arbitrary parameters. We also discussed the modulation instability analysis of the governing model. The constraint conditions for the validity of existence of solutions are also reported. Moreover, three-dimensional and two-dimensional, and their corresponding contour graphs are sketched for a better understanding of the derived solutions with the values of arbitrary parameters.
REGENERATION OF KNEE CARTILAGE DEFECTS: HUMAN CLINICAL TRIALS
Authors: Liu Yen-Liang , Liu Hwa-Chang
Published: April 2021

Osteoarthritis (OA) results from aging joints, injury, and obesity, emerging as an epidemic joint disease in addition to being a significant cause of pain disability. Despite decades of efforts from scientists and physicians, the trend of the global increase in the incidence of OA does not slow down. As there are no effective pharmacotherapies able to reverse the degenerative process, cell-based and biological therapies for OA were invented and developed into a thriving field of regenerative medicine for orthopedics. First, autologous chondrocyte implantation (ACI) has been used to treat osteoarticular defects for over two decades. While ACI has demonstrated its capability to decelerate OA progression, there are still many issues that hamper its therapeutic efficacy. Therefore, researchers and physicians invented innovative biomaterials-assisted cell therapies, advanced surgical techniques for preserving primary chondrocytes’ biological function and avoiding the donor-site mortality. Later, the discovery of mesenchymal stem cells (MSCs) revoluted cell therapies for cartilage repair. MSCs not only provide an alternative cell source with much higher proliferation rates but also have these advantages: no donor-site mortality, non-tumorigenic, and, most importantly, the capability of chondrogenic differentiation. This review paper explores the challenges associated with OA treatments using cell-based therapies and shares our vision for the future development of regenerative medicine for cartilage.
Automated Image Denoising Model: Contribution Towards Optimized Internal and External Basis
Authors: Kuzhali S. Elavaar , Suresh D. S.
Published: April 2021

For handling digital images for various applications, image denoising is considered as a fundamental pre-processing step. Diverse image denoising algorithms have been introduced in the past few decades. The main intent of this proposal is to develop an effective image denoising model on the basis of internal and external patches. This model adopts Non-local means (NLM) for performing the denoising, which uses redundant information of the image in pixel or spatial domain to reduce the noise. While performing the image denoising using NLM, “denoising an image patch using the other noisy patches within the noisy image is done for internal denoising and denoising a patch using the external clean natural patches is done for external denoising”. Here, the selection of optimal block from the entire datasets including internal noisy images and external clean natural images is decided by a new hybrid optimization algorithm. The two renowned optimization algorithms Chicken Swarm Optimization (CSO), and Dragon Fly Algorithm (DA) are merged, and the new hybrid algorithm Rooster-based Levy Updated DA (RLU-DA) is adopted. The experimental results in terms of some relevant performance measures show the promising results of the proposed model with remarkable stability and high accuracy.
Critical Value-Based Power Options Pricing Problems in Uncertain Financial Markets
Authors: Yang Guimin , Zhu Yuanguo
Published: April 2021

Compared with investing an ordinary options, investing the power options may possibly yield greater returns. On the one hand, the power option is the best choice for those who want to maximize the leverage of the underlying market movements. On the other hand, power options can also prevent the financial market changes caused by the sharp fluctuations of the underlying assets. In this paper, we investigate the power option pricing problem in which the price of the underlying asset follows the Ornstein–Uhlenbeck type of model involving an uncertain fractional differential equation. Based on critical value criterion, the pricing formulas of European power options are derived. Finally, some numerical experiments are performed to illustrate the results.
THE RELATIONSHIP BETWEEN ECONOMIC POLICY UNCERTAINTY AND CORPORATE TAX RATES
Authors: CLANCE MATTHEW , GOZGOR GIRAY , GUPTA RANGAN , LAU CHI KEUNG MARCO
Published: April 2021

This paper investigates the relationship between economic policy uncertainty and corporate tax rates in a panel dataset of 126 countries throughout 2003–2018. We use the so-called “World Uncertainty Index” to measure the level of economic policy uncertainty. We utilize various estimation techniques and find a one-way causality from economic policy uncertainty to corporate tax rates. Specifically, a rise in economic policy uncertainty leads to higher corporate tax rates. We also discuss potential implications.
Motion of a Rolling Hula Hoop
Authors: Kajiyama Yuji , Higuchi Koki
Published: April 2021

If one rolls a vertically standing hula hoop forward with backspin applied, it moves once far away and then eventually back to hand. In this paper, we study such a motion of a rolling hula hoop from both theoretical and experimental aspects. The hula hoop is rolling with slipping immediately after it leaves the hand, and its motion will transit to that of without slipping due to the transition of the frictional force from kinetic friction to static friction. We show that the experimental results analyzed by Tracker software can be well described by equations of motion that take into account the deformation of the hula hoop. Theoretical and experimental studies in this paper are suitable for university students in physics courses. The video analyzed in this paper can be viewed at https://youtu.be/i4j1lDhCI2os .
A Pedagogical Model of General Covariance Coupling Electrodynamics and Gravitation
Authors: Florence Tristan L. , McCully Curtis V. , Neuenschwander Dwight E.
Published: April 2021

In his 1951 model of the effects of a star’s radiation on its gravitation, P.C. Vaidya used radiation fields of flat spacetime. Wondering why Vaidya did not include the effects of gravitation on electrodynamics, we apply the principle of general covariance to gravitation and radiation. Others have addressed this problem with numerical methods, but, like Vaidya, we seek an analytic solution. Along the way, we see how prescient was Vaidya’s choice in modeling the radiation. Pursued originally as a pedagogical exercise with undergraduate physicists, our results compare favorably to similar models, and illustrate general relativity theorems. Given recent interest in teaching general relativity to undergraduates, a system that couples gravitation and electrodynamics and is solvable with elementary integrations may hold pedagogical interest.
Large Games: Robustness and Stability
Authors: Gradwohl Ronen , Kalai Ehud
Published: April 2021

This review focuses on properties related to the robustness and stability of Nash equilibria in games with a large number of players. Somewhat surprisingly, these equilibria become substantially more robust and stable as the number of players increases. We illustrate the relevant phenomena through a binary-action game with strategic substitutes, framed as a game of social isolation in a pandemic environment.
Enoyl coenzyme A hydratase 1 alleviates nonalcoholic steatohepatitis in mice by suppressing hepatic ferroptosis
Authors: Liu Bing , Yi Wei , Mao Xiaoxiang , Yang Ling , Rao Caijun
Published: April 2021

In summary, ECH1 may ameliorate steatohepatitis by inhibiting ferroptosis. Pharmacological or genetic ECH1 activation may have potential as a future therapy for NASH.
CT Texture Analysis for Preoperative Identification of Lymphoma from Other Types of Primary Small Bowel Malignancies
Authors: Liu Shunli , Zhang Chuanyu , Liu Ruiqing , Li Shaoke , Xu Fenglei , Liu Xuejun , Li Zhiming , Hu Yabin , Ge Yaqiong , Chen Jiao , Zhang Zaixian
Published: April 2021

Objectives. To explore the application of computed tomography (CT) texture analysis in differentiating lymphomas from other malignancies of the small bowel. Methods. Arterial and venous CT images of 87 patients with small bowel malignancies were retrospectively analyzed. The subjective radiological features were evaluated by the two radiologists with a consensus agreement. The region of interest (ROI) was manually delineated along the edge of the lesion on the largest slice, and a total of 402 quantified features were extracted automatically from AK software. The inter‐ and intrareader reproducibility was evaluated to select highly reproductive features. The univariate analysis and minimum redundancy maximum relevance (mRMR) algorithm were applied to select the feature subsets with high correlation and low redundancy. The multivariate logistic regression analysis based on texture features and radiological features was employed to construct predictive models for identification of small bowel lymphoma. The diagnostic performance of multivariate models was evaluated using receiver operating characteristic (ROC) curve analysis. Results. The clinical data (age, melena, and abdominal pain) and radiological features (location, shape, margin, dilated lumen, intussusception, enhancement level, adjacent peritoneum, and locoregional lymph node) differed significantly between the nonlymphoma group and lymphoma group (p < 0.05). The areas under the ROC curve of the clinical model, arterial texture model, and venous texture model were 0.93, 0.92, and 0.87, respectively. Conclusion. The arterial texture model showed a great diagnostic value and fitted performance in preoperatively discriminating lymphoma from nonlymphoma of the small bowel.
Ex Vivo Comparison of a UV-Polymerizable Methacrylate Adhesive versus an Inverting Pattern as the Second Layer of a Two-Layer Hand-Sewn Jejunal Anastomosis in Horses: A Pilot Study
Authors: Lenoir Augustin , Perrin Bertrand R. M. , Lepage Olivier M.
Published: April 2021

Resection and anastomosis of small intestine during colic can lead to adhesions and recurrent colic. Several methods are available to reduce the rate of adhesions in the postoperative period, such as the use of serosal barriers. Surgical glues form a smooth surface, are fast to apply, and could reduce surgery time when performing anastomosis. A recently developed UV-polymerizable methacrylate adhesive (UV-PMA) is designed to anchor into the biological tissues’ top surface offering sealant and a smooth cover over the anastomosis site. This adhesive was used ex vivo on fifteen samples of equine jejunum as the second layer of a two-layer anastomosis (1L-UV-PMA group) and compared to a two-layer anastomosis (simple continuous pattern covered with a Cushing pattern; 2L-CT group), in terms of feasibility, bursting strength pressure (BSP), luminal diameter reduction (LDR), and time of construction. Data were analysed using a paired t-test or a chi2-test (

P
<
0.05

). The results showed no statistical difference in BSP, LDR, or any mode of failure between the two anastomosis types. However, the glue anastomosis formed a tunnel-like anastomosis and shredded under pressure, before apparition of leakage, preventing its usage in clinical cases with this methodology. It was concluded that modification of the technique is warranted before testing in clinical cases. A preprint of a former version of the manuscript is available on researchsquare.com, which was not conducted to print and publication after peer reviewing. Since then, the manuscript has been modified to this current version.
Perceiving Excitation Characteristics from Interactions between Field Road and Vehicle via Vibration Sensing
Authors: Cheng Yuansheng , Li Xiaoqin , Man Xiaolan , Fan Feifan , Li Zhixiong
Published: April 2021

When agricultural vehicles operate in the field, the soft road excitation makes it difficult to measure the vehicle vibration. A camera-accelerator system can solve this issue by utilizing computer vision information; however, the relationship between the field road surface and the vehicle vibration response remains an unsolved problem. This study aims to investigate the correlation of the soft road excitation of different long-wave surfaces with the vehicle vibration response. Vibration equation between the vehicle and soft road surface system was established to produce an effective roughness model of the field soft road surface. In order to simulate the vehicle vibration state under different long-wave road surfaces, the soil rectangular pits with 21 kinds of different spans and depths were applied to the road surfaces, and a tractor vibration test system was built for vibration test. The frequency spectrum analysis was performed for the vibration response and the roughness signals of the road surfaces. The results showed that coefficient (R2) of frequency correlation between the roughness excitation and the original unevenness at the excitation point at the rear end of the rectangular soil pit fell within 0.9641∼0.9969. The main frequency band of the vibration response fell within 0∼3 Hz, and the phenomenon of quadruple frequency existed. The correlation of roughness excitation with quadruple frequency fell within 0.992165∼1. The primary excitation points were located at the rear end of the rectangular soil pit. In addition, it also indicated that when the vehicle was driven without autonomous power, the vehicle vibration frequency mainly depended on the excitation frequency of the field road surface and the frequency at the maximum vehicle vibration intensity was 2 or 3 times of that at the maximum field soft road excitation. These findings may provide a reference for optimal design of vibration reduction and control for agricultural vehicles.
[Retracted] Use of Medicinal Plants for Respiratory Diseases in Bahawalpur, Pakistan
Authors: Afzal Sadia , Ahmad Hafiz Ishfaq , Jabbar Abdul , Tolba Mahmoud M. , AbouZid Sameh , Irm Nimra , Zulfiqar Farheen , Iqbal Muhammad Zahid , Ahmad Shoaib , Aslam Zubair
Published: April 2021

The most common ethnomedicinal plants being effective in respiratory disorders were studied for the first time in Bahawalpur District. The herbal medication represents a low‐cost treatment for the local community. There is a need for documenting the traditional uses of plants for further investigation of bioactive compounds. Using a qualitative approach, the ethnobotanical data was collected from the district of Bahawalpur, Pakistan, from February 2018 to February 2020 through semistructured interviews with the local people and traditional healers. The quantitative analysis included use value, informant consensus factor, family importance value, and relative frequency citation. A total of 20 indigenous plants belonging to 17 families were documented from 185 informants. These plants were claimed to be used for the treatment of 10 respiratory ailments. The plant habit, part of the plant used, and mode of preparation were standardized for authentication. The herbs are the most used life form (55%), while trees and shrubs are also used. Leaves dominate with high use value (47.62%) followed by fruit, stem, flower, and other parts of plants. For the preparation of traditional remedies, decoction (76.19%) and extract (71.43%) are common preparation methods. However, other methods of paste infusion, powder juice, and ash are used to a lower extent. The plants with higher use value are Glycyrrhiza glabra, Acacia arabica, and Mentha piperita; these have significant potential therapeutic activity for respiratory disease. The ethnomedicinal importance of plants against respiratory diseases used by the local population (traditional healers) is the commercial availability of the herbal product. It is a first‐time study in this area to fill the gap between traditional practices and synthetic medicine to screen out the phytochemical and pharmacological properties of plants that have a highly futuristic use value to develop antibiotic drug with least side effects by using sustainable methods.
A Note on the Difference of Powers and Falling Powers
Authors: Sabar Taoufik
Published: April 2021

Combinatorial sums and binomial identities have appeared in many branches of mathematics, physics, and engineering. They can be established by many techniques, from generating functions to special series. Here, using a simple mathematical induction principle, we obtain a new combinatorial sum that involves ordinary powers, falling powers, and binomial coefficient at once. This way, and without the use of any complicated analytic technique, we obtain a result that already exists and a generalization of an identity derived from Sterling numbers of the second kind. Our formula is new, genuine, and several identities can be derived from it. The findings of this study can help for better understanding of the relation between ordinary and falling powers, which both play a very important role in discrete mathematics.
Differential Diagnosis Strategy between Lower Extremity Arterial Occlusive Disease and Lumbar Disc Herniation
Authors: Yang Shaofeng , Shao Yijie , Yan Qi , Wu Cenhao , Yang Huilin , Zou Jun
Published: April 2021

Considering the increasingly incidence rate of lower extremity arterial occlusive disease and difficult to distinguish from lumbar disc herniation, it is very necessary to exclude lower extremity arterial occlusive disease resulting in lower limb symptoms from lumbar disc herniation. More importantly, who have a higher risk of combining with lower extremity arterial occlusive disease and misdiagnosed as lumbar disc herniation? Why those patients are easy to be misdiagnosed as lumbar disc herniation? It is worth analyzing and discussing. The risk factors including age, gender, the medical history of high blood pressure, diabetes, smoking and coronary, pulse pressure, lumbar disc herniation segment and type, ankle‐brachial index, and straight leg raising test were observed. The Oswestry disability index and the Japanese Orthopedic Association score were collected preoperative, six months after posterior lumbar interbody fusion and six months after vascular interventional treatment to evaluate the symptoms relief and surgical efficacy. There was a statistically significant difference (P < 0.01) in pulse pressure, ankle‐brachial index, central disc herniation, and straight leg raising test between two groups. There was a high risk to missed diagnosis of lower extremity arterial occlusive disease and misdiagnosed as lumbar disc herniation when patients are with a mild central lumbar disc herniation, higher pulse pressure, lower ankle‐brachial index, and straight leg raising test negative. Therefore, sufficient history‐taking and cautious physical examinations contributed to find risk factors and attach importance to such patients and, further, to exclude lower extremity arterial occlusive disease from lumbar disc herniation using lower extremity vascular ultrasound examination.
Pulmonary Alveolar Microlithiasis: A Unique Case of Familial PAM Complicated by Transplant Rejection
Authors: Helmink Austin , Atiya Samir , Martinez Duarte Ernesto
Published: April 2021

Background. Pulmonary alveolar microlithiasis (PAM) is a rare lung disease characterized by the deposition of calcium phosphate microliths or calcospherites, within the alveolar airspace. Typical imaging findings demonstrate a “sandstorm” appearance due to bilateral, interstitial sand-like micronodularities with basal predominance. Methods and Results. We describe an unusual case of a 48-year-old male with severe, familial PAM ultimately treated with a bilateral lung transplant. Conclusions. PAM is a rare lung disease caused by a mutation in the SLC34A2 gene, which encodes for a sodium-phosphate cotransporter in type II alveolar cells, leading to accumulation of intra-alveolar phosphate causing microlith formation. PAM has an indolent course but can progress to chronic hypoxic respiratory failure, ultimately requiring lung transplant, the only known effective treatment.
A Hybrid Algorithm Based on a Modified Sine Cosine Algorithm and Least Square and Its Application to Microwave Imaging
Authors: Wang Meng , Lu Guizhen
Published: April 2021

With the rapid development of materials science and medical imaging technology, traditional optimization algorithms cannot solve the problem of inverse scattering of complex scatterers well. Therefore, more and more imaging algorithms for solving complex scatterers were proposed. In this paper, a novel hybrid algorithm is put forward for the microwave imaging problem. First, the proposed algorithm improves the search path of the traditional sine cosine algorithm, which obtains better global search capability. Second, the least square is introduced to form judging and contrasting mechanisms, which forms the parallel algorithm simultaneously, in order to make the proposed algorithm more suitable for the diverse microwave imaging problem. To prove the efficiency of the proposed algorithm, several examples, including ten benchmark functions, two engineering design problems, and three different microwave imaging problem tests are adopted. As expected, the results show that the proposed algorithm achieves not only superior optimal value but also the reconstruction of the complicated permittivity of the scatterer compared with several traditional optimization algorithms.