bluuebunny/crossref_metadata_2025 huggingface dataset:
Preload Optimization Method for Traveling-Wave Rotary Ultrasonic Motor
Authors: Sun Haoyu , Yin Hao , Liu Jiang , Zhang Xilong
Published: July 2021

Preload optimization is very important for ultrasonic motors’ design and application. In this paper, a novel method for a traveling-wave rotary ultrasonic motor is proposed. Firstly, based on linear regression and the analytic hierarchy process (AHP), the mapping between the drive characteristics, mechanical characteristics, speed stability, and preload of the traveling-wave-type rotary ultrasonic motor was established. Then, the characteristic curves of stalling torque, no-load speed, maximum efficiency, and speed stability with the change of preload method were measured with a new test platform. Finally, three traveling-wave rotary ultrasonic motors with optimized preload were used in a cooperative manipulator for validation. The experimental results showed that when the preload was optimized from 200 N to 310 N, the stalling torque of the motor increased by 20.7%, the maximum efficiency increased by 15.3%, the standard deviation of the speed decreased by 53.8%, and the no-load speed decreased by 5.5%. Therefore, it can be seen that the new preload optimization approach can significantly improve the performance indexes of ultrasonic motors and meet the practical requirements of direct-drive cooperative manipulators in engineering applications. The new preload optimization method offers advantages in motor output performance compared to conventional methods.
‘Forced’ Online Religion: Religious Minority and Majority Communities’ Media Usage during the COVID-19 Lockdown
Authors: Kühle Lene , Larsen Tina Langholm
Published: July 2021

On 11 March 2020, the Danish Prime Minister announced a forthcoming lockdown of Danish society due to the COVID-19 pandemic and shut down all public institutions, including the national church. Instructions for the lockdown of religious minority communities were issued a week later. The total lockdown of the Danish religious landscape is both historically unprecedented and radical in a global context, and it raises questions about mediatized religion and religion–state relations in a postsecular society. Building on quantitative and qualitative data collected during the lockdown and the gradual opening of society in 2020, this article examines the media usage of the Danish national church and of the 28 recognized Muslim communities. It reevaluates Heidi A. Campbell’s ‘religious-social shaping approach to technology’ by examining how religious communities sought to establish continuity between their offline and online practices to maintain authority and community cohesion. We conclude (1) that the willingness of religious communities to cooperate with authorities was high, (2) that the crisis affected religious communities’ organizational framework and societal position, and (3) that Campbell’s approach needs to pay further attention to the conflict-producing aspects of negotiations on digitalized rituals, the importance of transnationalism, and differences between minority and majority religion.
The Influence of Solar X-ray Flares on SAR Meteorology: The Determination of the Wet Component of the Tropospheric Phase Delay and Precipitable Water Vapor
Authors: Nina Aleksandra , Radović Jelena , Nico Giovanni , Popović Luka Č. , Radovanović Milan , Biagi Pier Francesco , Vinković Dejan
Published: July 2021

In this work, we study the impact of high-energy radiation induced by solar X-ray flares on the determination of the temporal change in precipitable water vapor (ΔPWV) as estimated using the synthetic aperture radar (SAR) meteorology technique. As recent research shows, this radiation can significantly affect the ionospheric D-region and induces errors in the estimation of the total electron content (TEC) by the applied models. Consequently, these errors are reflected in the determination of the phase delay and in many different types of measurements and models, including calculations of meteorological parameters based on SAR observations. The goal of this study is to quantify the impact of solar X-ray flares on the estimation of ΔPWV and provide an estimate of errors induced if the vertical total electron content (VTEC) is obtained by single layer models (SLM) or multiple layer models (MLM) (these models do not include ionosphere properties below the altitude of 90 km as input parameters and cannot provide information about local disturbances in the D-region). The performed analysis is based on a known procedure for the determination of the D-region electron density (and, consequently, the vertical total electron content in the D-region (VTECD)) using ionospheric observations by very low frequency (VLF) radio waves. The main result indicates that if the D-region, perturbed by medium-sized and intense X-ray flares, is not modeled, errors occur in the determination of ΔPWV. This study emphasizes the need for improved MLMs for the estimation of the TEC, including observational data at D-region altitudes during medium-sized and intense X-ray flare events.
Automatic Road Marking Extraction and Vectorization from Vehicle-Borne Laser Scanning Data
Authors: Yao Lianbi , Qin Changcai , Chen Qichao , Wu Hangbin
Published: July 2021

Automatic driving technology is becoming one of the main areas of development for future intelligent transportation systems. The high-precision map, which is an important supplement of the on-board sensors during shielding or limited observation distance, provides a priori information for high-precision positioning and path planning in automatic driving. The position and semantic information of the road markings, such as absolute coordinates of the solid lines and dashed lines, are the basic components of the high-precision map. In this paper, we study the automatic extraction and vectorization of road markings. Firstly, scan lines are extracted from the vehicle-borne laser point cloud data, and the pavement is extracted from scan lines according to the geometric mutation at the road boundary. On this basis, the pavement point clouds are transformed into raster images with a certain resolution by using the method of inverse distance weighted interpolation. An adaptive threshold segmentation algorithm is used to convert raster images into binary images. Followed by the adaptive threshold segmentation is the Euclidean clustering method, which is used to extract road markings point clouds from the binary image. Solid lines are detected by feature attribute filtering. All of the solid lines and guidelines in the sample data are correctly identified. The deep learning network framework PointNet++ is used for semantic recognition of the remaining road markings, including dashed lines, guidelines and arrows. Finally, the vectorization of the identified solid lines and dashed lines is carried out based on a line segmentation self-growth algorithm. The vectorization of the identified guidelines is carried out according to an alpha shape algorithm. Point cloud data from four experimental areas are used for road marking extraction and identification. The F-scores of the identification of dashed lines, guidelines, straight arrows and right turn arrows are 0.97, 0.66, 0.84 and 1, respectively.
Impact of Rapid Urban Sprawl on the Local Meteorological Observational Environment Based on Remote Sensing Images and GIS Technology
Authors: Zhang Yanhao , Ning Guicai , Chen Shihan , Yang Yuanjian
Published: July 2021

Rapid increases in urban sprawl affect the observational environment around meteorological stations by changing the land use/land cover (LULC) and the anthropogenic heat flux (AHF). Based on remote sensing images and GIS technology, we investigated the impact of changes in both LULC and AHF induced by urbanization on the meteorological observational environment in the Yangtze River Delta (YRD) during 2000–2018. Our results show that the observational environments around meteorological stations were significantly affected by the rapid expansion of built-up areas and the subsequent increase in the AHF, with a clear spatiotemporal variability. A positive correlation was observed between the proportion of built-up areas and the AHF around meteorological stations. The AHF was in the order urban stations > suburban stations > rural stations, but the increases in the AHF were greater around suburban and rural stations than around urban stations. Some meteorological stations need to be relocated to address the adverse effects induced by urbanization. The proportion of built-up areas and AHF around the new stations decreased significantly after relocation, weakening the urban heat island effect on the meteorological observations and substantially improving the observational environment. As a result, the observed daily mean temperature (relative humidity) decreased (increased) around the new stations after relocation. Our study comprehensively shows the impact of rapid urban sprawl on the observational environment around meteorological stations by assessing changes in both LULC and the AHF induced by urbanization. These findings provide scientific insights for the selection and construction of networks of meteorological stations and are therefore helpful in scientifically evaluating and correcting the impact of rapid urban sprawl on meteorological observations.
Evaluation and Hydrological Application of a Data Fusing Method of Multi-Source Precipitation Products-A Case Study over Tuojiang River Basin
Authors: Li Yao , Wang Wensheng , Wang Guoqing , Yu Siyi
Published: July 2021

Precipitation is an essential driving factor of hydrological models. Its temporal and spatial resolution and reliability directly affect the accuracy of hydrological modeling. Acquiring accurate areal precipitation needs substantial ground rainfall stations in space. In many basins, ground rainfall stations are sparse and uneven, so real-time satellite precipitation products (SPPs) have become an important supplement to ground-gauged precipitation (GGP). A multi-source precipitation fusion method suitable for the Soil and Water Assessment Tool (SWAT) model has been proposed in this paper. First, the multivariate inverse distance similarity method (MIDSM) was proposed to search for the optimal representative precipitation points of GGP and SPPs in sub-basins. Subsequently, the correlation-coefficient-based weighted average method (CCBWA) was presented and applied to calculate the fused multi-source precipitation product (FMSPP), which combined GGP and multiple satellite precipitation products. The effectiveness of the FMSPP was proven over the Tuojiang River Basin. In the case study, three SPPs were chosen as the satellite precipitation sources, namely the Climate Forecast System Reanalysis (CFSR), Tropical Rainfall Measuring Mission Project (TRMM), and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Network Climate Data Record (PERSIANN-CDR). The evaluation indicators illustrated that FMSPP could capture the occurrence of rainfall events very well, with a maximum Probability of Detection (POD) and Critical Success Index (CSI) of 0.92 and 0.83, respectively. Furthermore, its correlation with GGP, changing in the range of 0.84–0.96, was higher in most sub-basins on the monthly scale than the other three SPPs. These results demonstrated that the performance of FMSPP was the best compared with the original SPPs. Finally, FMSPP was applied in the SWAT model and was found to effectively drive the SWAT model in contrast with a single precipitation source. The FMSPP manifested the highest accuracy in hydrological modeling, with the Coefficient of Determination (R2) of 0.84, Nash Sutcliff (NS) of 0.83, and Percent Bias (PBIAS) of only −1.9%.
General Purpose Low-Level Reinforcement Learning Control for Multi-Axis Rotor Aerial Vehicles
Authors: Pi Chen-Huan , Dai Yi-Wei , Hu Kai-Chun , Cheng Stone
Published: July 2021

This paper proposes a multipurpose reinforcement learning based low-level multirotor unmanned aerial vehicles control structure constructed using neural networks with model-free training. Other low-level reinforcement learning controllers developed in studies have only been applicable to a model-specific and physical-parameter-specific multirotor, and time-consuming training is required when switching to a different vehicle. We use a 6-degree-of-freedom dynamic model combining acceleration-based control from the policy neural network to overcome these problems. The UAV automatically learns the maneuver by an end-to-end neural network from fusion states to acceleration command. The state estimation is performed using the data from on-board sensors and motion capture. The motion capture system provides spatial position information and a multisensory fusion framework fuses the measurement from the onboard inertia measurement units for compensating the time delay and low update frequency of the capture system. Without requiring expert demonstration, the trained control policy implemented using an improved algorithm can be applied to various multirotors with the output directly mapped to actuators. The algorithm’s ability to control multirotors in the hovering and the tracking task is evaluated. Through simulation and actual experiments, we demonstrate the flight control with a quadrotor and hexrotor by using the trained policy. With the same policy, we verify that we can stabilize the quadrotor and hexrotor in the air under random initial states.
Attention-Based 3D Human Pose Sequence Refinement Network
Authors: Kim Do-Yeop , Chang Ju-Yong
Published: July 2021

Three-dimensional human mesh reconstruction from a single video has made much progress in recent years due to the advances in deep learning. However, previous methods still often reconstruct temporally noisy pose and mesh sequences given in-the-wild video data. To address this problem, we propose a human pose refinement network (HPR-Net) based on a non-local attention mechanism. The pipeline of the proposed framework consists of a weight-regression module, a weighted-averaging module, and a skinned multi-person linear (SMPL) module. First, the weight-regression module creates pose affinity weights from a 3D human pose sequence represented in a unit quaternion form. Next, the weighted-averaging module generates a refined 3D pose sequence by performing temporal weighted averaging using the generated affinity weights. Finally, the refined pose sequence is converted into a human mesh sequence using the SMPL module. HPR-Net is a simple but effective post-processing network that can substantially improve the accuracy and temporal smoothness of 3D human mesh sequences obtained from an input video by existing human mesh reconstruction methods. Our experiments show that the noisy results of the existing methods are consistently improved using the proposed method on various real datasets. Notably, our proposed method reduces the pose and acceleration errors of VIBE, the existing state-of-the-art human mesh reconstruction method, by 1.4% and 66.5%, respectively, on the 3DPW dataset.
Targeted Expression of TGFBIp Peptides in Mouse and Human Tissue by MALDI-Mass Spectrometry Imaging
Authors: Anandalakshmi Venkatraman , Hochart Guillaume , Bonnel David , Stauber Jonathan , Shimmura Shigeto , Lakshminarayanan Rajamani , Pervushin Konstantin , Mehta Jodhbir S.
Published: July 2021

Stromal corneal dystrophies are a group of hereditary disorders caused by mutations in the TGFBI gene. The mutant TGFBIp is prone to protein aggregation and the mutant protein gets deposited in the cornea, leading to severe visual impairment. The mutations lead to a corneal specific protein aggregation suggesting the involvement of tissue-specific factors. The exact molecular mechanism of the process of tissue-specific protein aggregation remains to be elucidated. Differential proteolysis of mutant TGFBIp is a critical component of the disease pathology. The differential proteolysis gives rise to shorter peptides that are highly aggregation-prone and initiate the aggregation cascade. Analyzing the proteolytic processing of the different TGFBIp mutant may provide insight to aid in understanding the amyloid aggregation mechanism. We developed a MALDI-MSI methodology to identify expression and spatial localization of TGFBIp peptides in the cornea. Corneal tissue samples were collected from both control and dystrophic patients (with 2 different mutations), embedded in OCT and sectioned. The sections were trypsin digested and subjected to mass spectrometry imaging using a targeted approach to detect TGFBIp. MALDI-MSI identified peptides from TGFBIp that co-localized with the amyloid corneal deposits. In addition to the relative abundance data, the specific location of the peptides across the corneal sections as molecular signatures was also identified. Spatial distribution and intensity of the TGFBIp peptides showed differences between diseased and control models but also between the two LCD phenotypes. The TGFBIp peptide with m/z of 787.474 and m/z of 1179.579 showed increased expression in both LCD mutants compared to the controls. The peptide with m/z of 929.5 showed increased expression in the LCD phenotype with H626R mutation while the peptide with m/z of 1315.802 was abundant in the sample with R124C mutation. This initial report of 2D spatial protein signature and localization of TGFBIp may be expanded to other mutations to understand the proteolytic patterns of TGFBIp in different mutations.
Status Threat, Social Concerns, and Conservative Media: A Look at White America and the Alt-Right
Authors: Isom Deena , Boehme Hunter , Mikell Toniqua , Chicoine Stephen , Renner Marion
Published: July 2021

Racial and ethnic division is a mainstay of the American social structure, and today these strains are exacerbated by political binaries. Moreover, the media has become increasingly polarized whereby certain media outlets intensify perceived differences between racial and ethnic groups, political alignments, and religious affiliations. Using data from a recent psychological study of the Alt-Right, we assess the associations between perceptions of social issues, feelings of status threat, trust in conservative media, and affiliation with the Alt-Right among White Americans. We find concern over more conservative social issues along with trust in conservative media explain a large portion of the variation in feelings of status threat among White Americans. Furthermore, more conservative social issues plus feeling of status threat significantly increase the odds of Alt-Right affiliation. Most surprisingly, however, trust in conservative media mitigated, instead of amplified, these associations. Implications and calls for future research are discussed.
Construction of Biophysical Indicators for the Catalan Economy: Building a New Conceptual Framework
Authors: Manera Carles , Serrano Eloi , Pérez-Montiel José , Buil-Fabregà Màrian
Published: July 2021

The main objective of this work is to create an environmental vision of the Catalan economy based on various indicators. To do this, we started from the fundamental idea of obtaining new metrics to measure impacts on the economy. The methodology used is focused on the systematization of descriptive statistics and econometric review. In this sense, GDP and GDP per capita are valued as chrematistic units, and biophysical variables are incorporated. For the period 2000–2016, the figures for energy consumption, CO2 emissions, energy intensity of the economy and water consumption were collected. In addition, demographic evolution and the Gini index were also ordered as factors that contribute to explaining not only population trajectory but also some of the social factors. Greater technological efficiency in regard to environmental aspects is intuited as sensitive to the economic cycle. The study is novel in the panorama of the regional economy of Spain, by incorporating biophysical variables to the applied economic analysis.
Analysis of Drivers’ Eye Movements on Roundabouts: A Driving Simulator Study
Authors: Azimian Amin , Catalina Ortega Carlos Alberto , Espinosa Juan Maria , Mariscal Miguel Ángel , García-Herrero Susana
Published: July 2021

Roundabouts are considered as one of the most efficient forms of intersection that substantially reduce the types of crashes that result in injury or loss of life. Nevertheless, they do not eliminate collision risks, especially when human error plays such a large role in traffic crashes. In this study, we used a driving simulator and an eye tracker to investigate drivers’ eye movements under cell phone-induced distraction. A total of 45 drivers participated in two experiments conducted under distracted and non-distracted conditions. The results indicated that, under distracting conditions, the drivers’ fixation duration decreased significantly on roundabouts, and pupil size increased significantly.
Public Behavior as an Output of E-Government Service: The Role of New Technology Integrated in E-Government and Antecedent of Relationship Quality
Authors: Hariguna Taqwa , Ruangkanjanases Athapol , Sarmini
Published: July 2021

Electronic government has played an essential role in citizen policy strategy, especially during the COVID-19 pandemic. As part of citizen and government interaction, companies can utilize electronic government facilities to establish direct communication and maintain service quality by integrating new technologies and facilities in electronic government which can provide service via online, embedded with social media integration, implemented with mobile service, using personalized user accounts, e-participation service integration, in combination with ongoing citizen information. Therefore, electronic government facilities must adapt and choose the right content to promote strong citizen relations, leading to citizen behavior to make long-term use of electronic government facilities. This study considered and integrated the latest technology from electronic government and associated it with connection quality. Sustainable motives and faithfulness were used to quantify the quality of citizen relations to electronic government facilities, which can influence the results of citizen behavior. The SmartPLS 2 software was used to quantify and estimate 425 online questionnaire surveys. The results showed that of the 12 hypotheses, eight hypotheses were declared to have a significant effect, consisting of H1, H2, H6–H8, and H10–H12, while the other four hypotheses were stated to have no significant effect, namely H3–H5, and H9. This study was used to guide the government as a provider of electronic government facilities to adapt and provide content following the dimensions of the latest technology to achieve goals and produce sustainable implementation.
The Influence of COVID-19-Induced Daily Activities on Health Parameters—A Case Study in Malaysia
Authors: Ali Mujahid , de Azevedo Afonso R. G. , Marvila Markssuel T. , Khan Muhammad Imran , Memon Abdul Muhaimin , Masood Faisal , Almahbashi Najib Mohammed Yahya , Shad Muhammad Kashif , Khan Mudassir Ali , Fediuk Roman , Timokhin Roman , Borovkov Aleksey , Haq Ihtisham Ul
Published: July 2021

Since December 2019, the COVID-19 epidemic has been spreading all over the world. This epidemic has brought a risk of death in the daily activity (physical and social) participation that influences travellers’ physical, social, and mental health. To analyze the impact of the COVID-19-induced daily activities on health parameters of higher education institutes, 150 students of the Universiti Teknologi PETRONAS, Perak, Malaysia, were surveyed through an online web survey using random sampling techniques. The data were analyzed through RStudio and SPSS using multilevel linear regression analysis and Hierarchical Structural Equation Modeling. The estimated results indicate that restricting individuals from doing out-of-home activities negatively influences physical and social health. A unit increase in the in-home maintenance activities during the COVID-19 pandemic introduced a daily increase of 0.5% in physical health. Moreover, a unit increase in the in-home activities at leisure time represents a 1% positive improvement in social health. Thus, physical activity has proven to be beneficial in improving physical and social health with severe COVID-19. In contrast, the coefficient of determination (R2) for all endogenous variables ranges from 0.148 to 0.227, which is incredibly acceptable in psychological research. For a healthier society with a better quality of life, this study adopted multidisciplinary approaches that are needed to be designed.
Towards Sustainable Private Labels in an Autonomous Community during COVID-19—Analysis of Consumer Behavior and Perception on the Example of Tenerife
Authors: Czeczotko Maksymilian , Górska-Warsewicz Hanna , Laskowski Wacław , Rostecka Barbara
Published: July 2021

Our study aimed to analyze consumer behavior and perception towards private labels (PLs) in Tenerife as an autonomous community during COVID-19, with special attention given to sustainability aspects. The research was conducted on a sample of 500 adults purchasing PLs using quota selection and the CAWI method. We formulated four research questions related to factors of PL choice, the relationship between frequency of PL purchases, consumers’ age and income, perceived changes in PLs, and evaluation of PL products including sustainability. The latter research question referred to such product characteristics as local and environmentally friendly production, organic production, and production according to traditional technologies using only natural ingredients. For a detailed analysis of consumer behavior, we used Pearson’s chi-square test, the rho-Spearman correlation coefficient, and cluster analysis. The most important factors for purchasing PL products were lower prices compared to leading brands, attachment to a given chain, and the feeling of safety and trust in PL products. The frequency of purchase of PL food products, except for alcohol, significantly negatively correlates with age, which means that the purchase of PLs from the analyzed product categories decreases with age. The increased availability and improved image and quality of PLs were identified as the most important changes in PLs. PL food products were rated by consumers as fresh, minimally processed and with quality certificates. Environmentally friendly production methods, nutritional value, and origin from an area close to home were also indicated.
Contributions from Literature for Understanding Wine Marketing
Authors: Martinho Vítor João Pereira Domingues
Published: July 2021

Marketing for wines is a determinant tool for several stakeholders within the wine sector, but there are not many studies concerning the topic “wine marketing” and even fewer that take a bibliometric approach. In turn, wine is a strategic agri-food product for the economy of several countries around the world, particularly in Mediterranean countries. Beyond the economic level, wine has an environmental, social, and cultural dimension. All these dimensions have implications in any plan for the wine sector and should be taken into account. In addition, these dimensions change around the world in accordance with different local factors. In this way, sometimes, it is not easy to design adjusted marketing plans for the wine sector, namely, in international markets. Taking the frameworks into account, the main objective of this study is to explore the scientific documents available on scientific platforms, namely, in the Web of Science, related to “wine marketing”. These studies (87 documents) were first explored through bibliometric software, such as the VOSviewer and the Atlas.ti, and then analyzed individually to capture the main insights shown by the scientific literature about wine marketing. To better organize the literature survey, with the information obtained from the bibliometric analysis, the following indexes were identified through factor analysis: “supply index”, “demand index”, “winery strategy index”, “tourism index”, “innovation index”, and “wine characteristics index”. The supply index highlights questions related to new technologies, climate change, logistics in international markets, institutions and regulations, being the main factors that influence wine producers. The demand index stresses the relevance, for consumers, of the relationship between the price and quality of a wine. On the other hand, younger consumers, in general, consume wine outdoors while socializing, giving importance to the label, often when the wine is recommended by someone. Older consumers give greater importance to the wine’s variety and to its region of origin. The winery strategy index shows the importance of questions relating to agri-chains, market differentiation, the history, and the brand. The tourism index brings together aspects associated with the complementarity between activities in the wine sector, wine routes, and contributions from culture and landscape. The innovation index highlights aspects related to the quality and the perceptions of the consumers. Finally, the wine characteristics index shows the little importance given by scientific literature relating to wine marketing and to attributes such as alcohol. A search on the Web of Science for the topic addressed here and “bibliometric” showed that there has been no research carried out with the approach taken here, showing the novelty of this study.
Comprehensive View of Topological Optimization Scooter Frame Design and Manufacturing
Authors: Mesicek Jakub , Jancar Lukas , Ma Quoc-Phu , Hajnys Jiri , Tanski Tomasz , Krpec Pavel , Pagac Marek
Published: July 2021

The combination of topology optimization (TO) and 3D printing has revolutionized the way components are designed and fabricated. In view of this, this manuscript presents a TO workflow considering the frame of a scooter. In particular, TO is employed to redesign the scooter frame based on a commercial one. The topologically optimized frame is then fabricated with stainless steel 316L utilizing the selective laser melting (SLM) method. In particular, technical obstacles encountered during the process and according solutions are recorded. Given the herein notes, readers who are working with the two technologies can anticipate the technical problems and deliver more effective solutions should any of them arise.
Research on WebShell Detection Method Based on Regularized Neighborhood Component Analysis (RNCA)
Authors: Zhou Aijun , Luktarhan Nurbol , Ai Zhuang
Published: July 2021

The variant, encryption, and confusion of WebShell results in problems in the detection method based on feature selection, such as poor detection effect and weak generalization ability. In order to solve this problem, a method of WebShell detection based on regularized neighborhood component analysis (RNCA) is proposed. The RNCA algorithm can effectively reduce the dimension of data while ensuring the accuracy of classification. In this paper, it is innovatively applied to a WebShell detection neighborhood, taking opcode behavior sequence features as the main research object, constructing vocabulary by using opcode sequence features with variable length, and effectively reducing the dimension of WebShell features from the perspective of feature selection. The opcode sequence selected by the algorithm is symmetrical with the source code file, which has great reference value for WebShell classification. On the issue of the single feature, this paper uses the fusion of behavior sequence features and text static features to construct a feature combination with stronger representation ability, which effectively improves the recognition rate of WebShell to a certain extent.
Spectral Curves for the Derivative Nonlinear Schrödinger Equations
Authors: Smirnov Aleksandr O.
Published: July 2021

Currently, in nonlinear optics, models associated with various types of the nonlinear Schrödinger equation (scalar (NLS), vector (VNLS), derivative (DNLS)), as well as with higher and mixed equations from the corresponding hierarchies are usually studied. Typical tools for solving the problem of propagation of optical nonlinear waves are the forward and inverse nonlinear Fourier transforms. One of the methods for reconstructing a periodic nonlinear signal is based on the use of spectral data in the form of spectral curves. In this paper, we study the properties of the spectral curves for all the derivatives NLS equations simultaneously. For all the main DNLS equations (DNLSI, DNLSII, DNLSIII), we have obtained unified Lax pairs, unified hierarchies of evolutionary and stationary equations, as well as unified equations of spectral curves of multiphase solutions. It is shown that stationary and evolutionary equations have symmetries, the presence of which leads to the existence of holomorphic involutions on spectral curves. Because of this symmetry, spectral curves of genus g are covers over other curves of genus M and N=g−M, where M is a number of phase of solutions. We also showed that the number of the genus g of the spectral curve is related to the number of phases M of the solution of one of the two formulas: g=2M or g=2M+1. The third section provides examples of the simplest solutions.
Prevalence of Malaria and Leptospirosis Co-Infection among Febrile Patients: A Systematic Review and Meta-Analysis
Authors: Wilairatana Polrat , Mala Wanida , Rattaprasert Pongruj , Kotepui Kwuntida Uthaisar , Kotepui Manas
Published: July 2021

Malaria and leptospirosis are important cosmopolitan infections that have emerged with overlapping geographic distribution, especially in tropical and subtropical regions. Therefore, co-infection with malaria and leptospirosis may occur in overlapping areas. The present study aimed to quantify the prevalence of malaria and leptospirosis co-infection among febrile patients. The association between malaria and leptospirosis infections was also investigated. Relevant studies that had reported malaria and leptospirosis co-infection were identified from PubMed, Scopus, and Web of Science. The risk of bias of the studies was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Tool. The pooled prevalence of malaria and leptospirosis co-infections among febrile patients and the pooled prevalence of leptospirosis infection among malaria patients were estimated using random effect models. The association between malaria and leptospirosis infection among febrile patients was estimated using random effect models. The outcomes of each study were shown in a forest plot in point estimate and 95% confidence interval (CI). Heterogeneity among the included studies was assessed using Cochran’s Q and quantified using I-squared statistics. For leptospirosis, subgroup analyses of countries, diagnostic tests, and participants’ age groups were performed to specify prevalence in each subgroup. Publication bias was assessed by funnel-plot visualization. Of the 2370 articles identified from the databases, 15 studies met the eligibility criteria and were included for qualitative and quantitative syntheses. Most of the included studies were conducted in India (5/15, 33.3%), Thailand (3/15, 20%), and Cambodia (2/15, 13.3%). Most of the enrolled cases were febrile patients (5838 cases) and malaria-positive patients (421 cases). The meta-analysis showed that the pooled prevalence of malaria and leptospirosis co-infection (86 cases) among febrile patients was 1% (95% CI: 1–2%, I2: 83.3%), while the pooled prevalence of leptospirosis infection (186 cases) among malaria patients was 13% (95% CI: 9–18%, I2: 90.3%). The meta-analysis showed that malaria and leptospirosis co-infections occurred by chance (p: 0.434, OR: 1.4, 95% CI: 0.6–3.28, I2: 85.2%). The prevalence of malaria in leptospirosis co-infection among febrile patients in the included studies was low. Co-infection was likely to occur by chance. However, as clinical symptoms of leptospirosis patients were non-specific and not distinguishable from symptoms of malaria patients, clinicians caring for febrile patients in an area where those two diseases are endemic should maintain a high index of suspicion for both diseases and whether mono-infections or co-infections are likely. Recognition of this co-infection may play an important role in reducing disease severity and treatment duration.
Anisotropic Cosmological Model in a Modified Theory of Gravitation
Authors: Tiwari Rishi Kumar , Beesham Aroonkumar , Mishra Soma , Dubey Vipin
Published: July 2021

Current observations indicate that, on a large enough scale, the universe is homogeneous and isotropic. However, this does not preclude the possibility of some anisotropy having occurred during the early stages of the evolution of the universe, which could then have been damped out later. This idea has aroused interest in the Bianchi models, which are homogeneous but anisotropic. Secondly, there is much interest in modified gravity these days due to the problems that the usual ΛCDM model faces in general relativity. Hence, in this paper, a study was conducted on the Bianchi type-I cosmological model in f(R,T)-modified gravity. Following some ideas from cosmography, a specific form of the deceleration parameter was assumed, leading to a model that exhibited a transition from early deceleration to late-time acceleration. The derived model approached isotropy at late times. The physical properties of the model were discussed, and expressions for the various parameters of the model were derived. It is also possible to make progress towards solving the cosmological constant problem, since in this model in f(R,T) gravity, a variable cosmological-type parameter arose, which was large early on but decreased to a constant value in later times.
Gravitationally Induced Particle Production through a Nonminimal Torsion–Matter Coupling
Authors: Harko Tiberiu , Lobo Francisco S. N. , Saridakis Emmanuel N.
Published: July 2021

We investigate the possibility of gravitationally generated particle production via the mechanism of nonminimal torsion–matter coupling. An intriguing feature of this theory is that the divergence of the matter energy–momentum tensor does not vanish identically. We explore the physical and cosmological implications of the nonconservation of the energy–momentum tensor by using the formalism of irreversible thermodynamics of open systems in the presence of matter creation/annihilation. The particle creation rates, pressure, and the expression of the comoving entropy are obtained in a covariant formulation and discussed in detail. Applied together with the gravitational field equations, the thermodynamics of open systems lead to a generalization of the standard ΛCDM cosmological paradigm, in which the particle creation rates and pressures are effectively considered as components of the cosmological fluid energy–momentum tensor. We consider specific models, and we show that cosmology with a torsion–matter coupling can almost perfectly reproduce the ΛCDM scenario, while it additionally gives rise to particle creation rates, creation pressures, and entropy generation through gravitational matter production in both low and high redshift limits.
Fishing for the Virome of Tropical Tuna
Authors: Gadoin Elsa , Desnues Christelle , Monteil-Bouchard Sonia , Bouvier Thierry , Auguet Jean-Christophe , Roque d’Orbcastel Emmanuelle , Bettarel Yvan
Published: July 2021

While planktonic viruses have received much attention in recent decades, knowledge of the virome of marine organisms, especially fish, still remains rudimentary. This is notably the case with tuna, which are among the most consumed fish worldwide and represent considerable economic, social and nutritional value. Yet the composition of the tuna virome and its biological and environmental determinants remain unknown. To begin to address this gap, we investigated the taxonomic diversity of viral communities inhabiting the skin mucus, gut and liver of two major tropical tuna species (skipjack and yellowfin) in individuals fished in the Atlantic and Indian Oceans. While we found significant differences in the virome composition between the organs, this was totally independent of the tuna species or sex. The tuna virome was mainly dominated by eukaryotic viruses in the digestive organs (gut and liver), while bacteriophages were predominant in the mucus. We observed the presence of specific viral families in each organ, some previously identified as fish or human pathogens (e.g., Iridoviridae, Parvoviridae, Alloherpesviridae, Papillomaviridae). Interestingly, we also detected a ‘core virome’ that was shared by all the organs and was mainly composed of Caudovirales, Microviridae and Circoviridae. These results show that tuna host a mosaic of viral niches, whose establishment, role and circulation remain to be elucidated.
Potential Prophylactic Treatments for COVID-19
Authors: Ben-Zuk Noam , Dechtman Ido-David , Henn Itai , Weiss Libby , Afriat Amichay , Krasner Esther , Gal Yoav
Published: July 2021

The World Health Organization declared the SARS-CoV-2 outbreak a Public Health Emergency of International Concern at the end of January 2020 and a pandemic two months later. The virus primarily spreads between humans via respiratory droplets, and is the causative agent of Coronavirus Disease 2019 (COVID-19), which can vary in severity, from asymptomatic or mild disease (the vast majority of the cases) to respiratory failure, multi-organ failure, and death. Recently, several vaccines were approved for emergency use against SARS-CoV-2. However, their worldwide availability is acutely limited, and therefore, SARS-CoV-2 is still expected to cause significant morbidity and mortality in the upcoming year. Hence, additional countermeasures are needed, particularly pharmaceutical drugs that are widely accessible, safe, scalable, and affordable. In this comprehensive review, we target the prophylactic arena, focusing on small-molecule candidates. In order to consolidate a potential list of such medications, which were categorized as either antivirals, repurposed drugs, or miscellaneous, a thorough screening for relevant clinical trials was conducted. A brief molecular and/or clinical background is provided for each potential drug, rationalizing its prophylactic use as an antiviral or inflammatory modulator. Drug safety profiles are discussed, and current medical indications and research status regarding their relevance to COVID-19 are shortly reviewed. In the near future, a significant body of information regarding the effectiveness of drugs being clinically studied for COVID-19 is expected to accumulate, in addition to information regarding the efficacy of prophylactic treatments.
Molecular Evolution and Epidemiological Characteristics of SARS COV-2 in (Northwestern) Poland
Authors: Serwin Karol , Ossowski Andrzej , Szargut Maria , Cytacka Sandra , Urbańska Anna , Majchrzak Adam , Niedźwiedź Anna , Czerska Ewa , Pawińska-Matecka Anna , Gołąb Joanna , Parczewski Miłosz
Published: July 2021

The emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) evolved into a worldwide outbreak, with the first Polish cases in February/March 2020. This study aimed to investigate the molecular epidemiology of the circulating virus lineages between March 2020 and February 2021. We performed variant identification, spike mutation pattern analysis, and phylogenetic and evolutionary analyses for 1106 high-coverage whole-genome sequences, implementing maximum likelihood, multiple continuous-time Markov chain, and Bayesian birth–death skyline models. For time trends, logistic regression was used. In the dataset, virus B.1.221 lineage was predominant (15.37%), followed by B.1.258 (15.01%) and B.1.1.29 (11.48%) strains. Three clades were identified, being responsible for 74.41% of infections over the analyzed period. Expansion in variant diversity was observed since September 2020 with increasing frequency of the number in spike substitutions, mainly H69V70 deletion, P681H, N439K, and S98F. In population dynamics inferences, three periods with exponential increase in infection were observed, beginning in March, July, and September 2020, respectively, and were driven by different virus clades. Additionally, a notable increase in infections caused by the B.1.1.7 lineage since February 2021 was noted. Over time, the virus accumulated mutations related to optimized transmissibility; therefore, faster dissemination is reflected by the second wave of epidemics in Poland.
Effects of Basic Amino Acids and Their Derivatives on SARS-CoV-2 and Influenza-A Virus Infection
Authors: Melano Ivonne , Kuo Li-Lan , Lo Yan-Chung , Sung Po-Wei , Tien Ni , Su Wen-Chi
Published: July 2021

Amino acids have been implicated with virus infection and replication. Here, we demonstrate the effects of two basic amino acids, arginine and lysine, and their ester derivatives on infection of two enveloped viruses, SARS-CoV-2, and influenza A virus. We found that lysine and its ester derivative can efficiently block infection of both viruses in vitro. Furthermore, the arginine ester derivative caused a significant boost in virus infection. Studies on their mechanism of action revealed that the compounds potentially disturb virus uncoating rather than virus attachment and endosomal acidification. Our findings suggest that lysine supplementation and the reduction of arginine-rich food intake can be considered as prophylactic and therapeutic regimens against these viruses while also providing a paradigm for the development of broad-spectrum antivirals.
Development of Bacteriophage Virus-Like Particle Vaccines Displaying Conserved Epitopes of Dengue Virus Non-Structural Protein 1
Authors: Warner Nikole L. , Frietze Kathryn M.
Published: July 2021

Dengue virus (DENV) is a major global health problem, with over half of the world’s population at risk of infection. Despite over 60 years of efforts, no licensed vaccine suitable for population-based immunization against DENV is available. Here, we describe efforts to engineer epitope-based vaccines against DENV non-structural protein 1 (NS1). NS1 is present in DENV-infected cells as well as secreted into the blood of infected individuals. NS1 causes disruption of endothelial cell barriers, resulting in plasma leakage and hemorrhage. Immunizing against NS1 could elicit antibodies that block NS1 function and also target NS1-infected cells for antibody-dependent cell cytotoxicity. We identified highly conserved regions of NS1 from all four DENV serotypes. We generated synthetic peptides to these regions and chemically conjugated them to bacteriophage Qβ virus-like particles (VLPs). Mice were immunized two times with the candidate vaccines and sera were tested for the presence of antibodies that bound to the cognate peptide, recombinant NS1 from all four DENV serotypes, and DENV-2-infected cells. We found that two of the candidate vaccines elicited antibodies that bound to recombinant NS1, and one candidate vaccine elicited antibodies that bound to DENV-infected cells. These results show that an epitope-specific vaccine against conserved regions of NS1 could be a promising approach for DENV vaccines or therapeutics to bind circulating NS1 protein.