bluuebunny/crossref_metadata_2025 huggingface dataset:
The Design and Evaluation of an Orange-Fruit Detection Model in a Dynamic Environment Using a Convolutional Neural Network
Authors: Zeeshan Sadaf , Aized Tauseef , Riaz Fahid
Published: March 2023

Agricultural robots play a crucial role in ensuring the sustainability of agriculture. Fruit detection is an essential part of orange-harvesting robot design. Ripe oranges need to be detected accurately in an orchard so they can be successfully picked. Accurate fruit detection in the orchard is significantly hindered by the challenges posed by the illumination and occlusion of fruit. Hence, it is important to detect fruit in a dynamic environment based on real-time data. This paper proposes a deep-learning convolutional neural network model for orange-fruit detection using a universal real-time dataset, specifically designed to detect oranges in a complex dynamic environment. Data were annotated and a dataset was prepared. A Keras sequential convolutional neural network model was prepared with a convolutional layer-activation function, maximum pooling, and fully connected layers. The model was trained using the dataset then validated by the test data. The model was then assessed using the image acquired from the orchard using Kinect RGB-D camera. The model was then run and its performance evaluated. The proposed CNN model shows an accuracy of 93.8%, precision of 98%, recall of 94.8%, and F1 score of 96.5%. The accuracy was mainly affected by the occlusion of oranges and leaves in the orchard’s trees. Varying illumination was another factor affecting the results. Overall, the orange-detection model presents good results and can effectively identify oranges in a complex real-time environment, like an orchard.
A Flow-Based Formulation of the Travelling Salesman Problem with Penalties on Nodes
Authors: Kowalik Przemysław , Sobecki Grzegorz , Bawoł Piotr , Muzolf Paweł
Published: March 2023

The travelling salesman problem (TSP) is one of combinatorial optimization problems of huge importance to practical applications. However, the TSP in its “pure” form may lack some essential issues for a decision maker—e.g., time-dependent travelling conditions. Among those shortcomings, there is also a lack of possibility of not visiting some nodes in the network—e.g., thanks to the existence of some more cost-efficient means of transportation. In this article, an extension of the TSP in which some nodes can be skipped at the cost of penalties for skipping those nodes is presented under a new name and in a new mathematical formulation. Such an extension can be applied as a model for transportation cost reduction due to the possibility of outsourcing deliveries to some nodes in a TSP route. An integer linear programming formulation of such a problem based on the Gavish–Graves-flow-based TSP formulation is introduced. This formulation makes it possible to solve the considered problem by using any integer linear programming optimization software. Numerical examples and opportunities for further research are presented.
Influence of Passenger Capacity on Fatigue Life of Gearbox Suspender of the Traction Transmission System in Urban Railway Vehicles
Authors: Huang Xianghe , Wang Jinhai , Yang Jianwei , Zhao Yue , Wang Yuzhu
Published: March 2023

Fatigue damage is the most dangerous failure behavior for gearbox suspenders in urban railway vehicles, and passenger capacity is crucial to the dynamic load characteristics of the traction transmission system. Therefore, in this paper, a dynamic model of the motor car is established, and a numerical simulation is carried out under different speeds and curve radii to investigate the effect of passenger capacity on fatigue life. The research results show that passenger capacity is an essential factor affecting the fatigue life of suspenders. As the vehicle runs at an average speed, the fatigue life of the suspender is 1.07 × 106 km when the passenger capacity is 120 people; when there are 240 people, the fatigue life reduction is 60%, while it is 86% at 339 people and 92% at 389 people. The per capita fatigue damage under a straight line is 7.27 × 10−10 at 20 km/h but 1.23 × 10−8 at 60 km/h. The per capita fatigue damage under a curved line is 7.18 × 10−9 in the 600 m curve but 9.00 × 10−9 in the 400 m curve. It can be concluded that the effect of speed is more significant than the curve radius. This research achievement can provide theoretical support for vehicle design and maintenance decisions.
Re-Imagining Heritage Tourism in Post-COVID Sub-Saharan Africa: Local Stakeholders’ Perspectives and Future Directions
Authors: Giliberto Francesca , Labadi Sophia
Published: March 2023

Tourism strategies implemented all over the world have often been demonstrably far from sustainable. The outbreak of the COVID-19 pandemic and its dramatic effects on the tourism sector worldwide present a unique transformative opportunity to reframe tourism in more sustainable ways. This article uses qualitative research methods and ethnography to advance knowledge on the impacts, both positive and negative, of the COVID-19 pandemic on tourism and heritage sites, as perceived by local stakeholders living and/or working at six popular heritage destinations in Sub-Saharan Africa, located in Kenya, Tanzania, and South Africa. The article discusses ways to rethink heritage-based tourism strategies more sustainably, according to the viewpoint of the research participants, and identifies new emerging tourism opportunities triggered by the pandemic, cutting across different local contexts to highlight more widely generalisable research findings. Identified strategies include diversifying tourism products at heritage sites; improving tourism marketing, visitors’ experience, and infrastructures; fostering more inclusive, co-operative, and integrated tourism and heritage management systems; increasing awareness of local resources while promoting ecotourism and responsible travel; and supporting economic diversification and local entrepreneurship.
Thermal Radiation and Mass Transfer Analysis in an Inclined Channel Flow of a Clear Viscous Fluid and H2O/EG-Based Nanofluids through a Porous Medium
Authors: Pavithra K. M. , Hanumagowda B. N. , Raju S. Suresh Kumar , Varma S. V. K. , Murshid Nimer , Mulki Hasan , Al-Kouz Wael
Published: March 2023

Nanofluid flow has acquired various interesting dimensions with the advent of several novel approaches to studying thermophysical properties. The present work focuses on a comparative study of clear viscous and nanofluid (EG−Al2O3, EG−Zr, H2O−Al2O3, H2O−Zr) flow in a two-phase inclined channel saturated with a porous medium in the presence of thermal radiation, species diffusion, and viscous and Darcy dissipation effects. The controlling equations of the flow model were solved analytically using the regular perturbation technique. The graphical solutions are used to examine the impacts of physical parameters on the most significant flow features. Surface graphs with distinct entrenched parameters represent heat transfer rates and shear stresses on plates. The resulting heat transfer was enhanced by raising the thermal and solute buoyancy strengths, while thermal radiation had the opposite outcome. This enhancement of temperature was maximum for water–zirconium and minimum for ethylene glycol–aluminum oxide nanofluid. The concentration of the entire fluid medium is reduced by decreased mass diffusivity. The enhancement of temperature and velocity is found to be maximum in the nanofluid region and clear fluid region, respectively. This study is validated with previously published works to demonstrate its effectiveness.
Geotechnical Properties and Stabilization Mechanism of Nano-MgO Stabilized Loess
Authors: Chen Shufeng , Ni Pengfei , Sun Zhao , Yuan Kekuo
Published: March 2023

This study focused on the utilization of nano-MgO as an energy-saving and eco-friendly stabilizer to improve the engineering performance of loess. To this end, loess samples at various nano-MgO contents and curing times were prepared, and then standard compaction, consistency limits, and unconfined compression tests were performed. The achieved results demonstrated that adding nano-MgO increased the liquid limit, plastic limit, and optimum water content of loess, while it decreased the plastic index and maximum dry density. The unconfined compressive strength (UCS) presented an increasing trend with curing time and a “rise-fall” trend with the addition of nano-MgO. At the optimum nano-MgO content of 2%, about 72% UCS gain was to be expected with 28 days of curing. The variation of the deformation modulus was similar to that of UCS, and the strain at failure presented an opposite trend. Empirical models for these properties were formulated and validated by literature data. Finally, from NMR analyses, the improving mechanism was found to be nano-MgO induced water transformation from free water to bound water.
Relational Capital in the Technology Sector: An International Strategic Model
Authors: Peces María del Carmen , Trillo María Amalia
Published: March 2023

This paper analyses the impact of relational capital and relationship networks on business internationalisation, in particular in the technology sector in relation to internationalised Andalusian university spin-offs. First, a literature review based on these theories is carried out, from which a series of hypotheses are established in a pioneering way. These allow us to design a model of relationships that is empirically tested through a quantitative analysis. The study constructs were measured using five-point Likert scales. Once the data had been collected through the survey developed, they were coded for statistical analysis using the SPSS Statistics V28.0 programme. It is shown that the output of the international activity of these companies depends on their capacity to develop and sustain relationships with each of the different actors involved. Along this line, university spin-offs obtain diverse and strategically valuable external information and resources, significantly reducing business failure chances. The elements that influence the internationalisation process of the companies under study are relationships with customers, allies/collaborators, suppliers, and the company’s reputation and image. Similarly, those referring to relations with competitors, public bodies, and organisations have less impact. Nevertheless, it is evident that companies need to commit more time and resources to create, maintain, and develop relationships with different actors. Therefore, a strategic tool focused on international management is provided, based on the relationships of the spin-offs studied, which may constitute a starting point for its applicability to other industrial sectors and geographical areas.
Spatiotemporal Characteristics and Determinants of Tourism Cooperation Network in Beijing–Tianjin–Hebei Region
Authors: Pan Yue , An Zhaolong , Li Jianpu , Weng Gangmin , Li Lingyan
Published: March 2023

The optimization of the cooperation network is a key link to accelerate the high-quality development of regional tourism. Taking the Beijing–Tianjin–Hebei region as an example, this paper measures the tourism cooperation intensity with the modified gravity model, on which the original, binary, and Top networks are generated to identify the spatiotemporal evolution characteristics from the multi-dimensional difference–association–agglomeration model, and provide insight into the determinants by the GeoDetector model. The results show that (1) the cooperation network reveals a diffusion trend with Beijing–Tianjin as the main axis chain, and southward expansion, and the overall differences tend to moderate at a slow pace, among which the north is the weak area. (2) The robustness of the cooperation network association structure is enhanced, showing that the outgoing equilibrium is improved, while the cohesion is strengthened and accessibility changes little. Furthermore, the cities show a core–edge distribution pattern in terms of power roles. (3) The cooperation network shows the phenomenon of hierarchical agglomeration gradually with the expansion of network scale, and eventually evolves into two camps: the Beijing–Tianjin cooperation circle and the Shijiazhuang–Xingtai cooperation circle. (4) Tourism cooperation belongs to the locational traffic constraint type, and making up for the shortcomings of rural development is another key to further enhancing regional tourism cooperation. The future optimization of regional tourism cooperation needs to seek multifactorial promotion paths.
Date Fruit Production and Consumption: A Perspective on Global Trends and Drivers from a Multidimensional Footprint Assessment
Authors: Sporchia Fabio , Patrizi Nicoletta , Pulselli Federico Maria
Published: March 2023

Date production and consumption is mostly diffused in Middle East and Northern African countries. Date production is linked to the land and water footprint in countries where agricultural land and freshwater are scarce. We estimate the global land, green water, blue water, and water scarcity footprint at the country scale from a production perspective. We show that production trends are increasingly driven by foreign demand. By tracking the international trade dynamics of dates, we map the shift of environmental footprint from the producing to the consuming countries. We find that dates production and consumption are not yet decoupled from the associated environmental burden. Global dates consumption accounted for 1.4 million hectares of agricultural land, 5.8 Gm3 of green water, 7.5 Gm3 of blue water, and the related impact on water scarcity reached 358 Gm3 world equivalent in 2019. The primacy of the economic driver is revealed, indicating that in the case of dates, the environmental sustainability aspects are currently overlooked for the sake of the economic benefit. The time-series analysis provides informative results to support policymakers in the design of mitigation strategies that can help the achievement of the SDGs.
Inequality in Fossil Fuel Power Plants in China: A Perspective of Efficiency and Abatement Cost
Authors: Choi Yongrok , Ma Yunning , Zhao Yu , Lee Hyoungsuk
Published: March 2023

Quantifying the shadow price (SP) of CO2 emissions is the key to achieving China’s “double carbon” targets. Considering technology heterogeneity, this study applies stochastic frontier analysis combined with meta-frontier technology to estimate the environmental technical efficiency (ETE) and SP of CO2 emissions for China’s fossil fuel power plants from 2005 to 2015. This approach overcomes the lack of statistical inference and consistency of traditional methods and improves the reliability of results. The main results are as follows: (a) the average ETE of China’s power plants is 0.9444, indicating that inefficient production accounts for 5.66%. The difference in efficiency between the central and local groups is significant. (b) The national average SP of CO2 is 266.8 US dollars per ton, which is much higher than the carbon price in the emission trading system. This result implies the need to design a carbon trading price mechanism. (c) The distribution of SP shows obvious corporation and geographical characteristics that are closely related to the level of regional economic development. Finally, the findings provide policy implications for the improvement of the efficiency and abatement of costs of power plants and the determination of carbon prices.
Sustainable Environmental Development from the Regional Perspective—The Interesting Case of Poland
Authors: Tejada-Gutiérrez Eva-Luz , Koloszko-Chomentowska Zofia , Fiore Mariantonietta , Spada Alessia
Published: March 2023

The EU regional development policy aims to reduce through its cohesion policy the socio-economic development disparities between its most developed regions and peripheral regions. Research shows that despite this strategy, the economic development of EU countries in the spatial system is not homogeneous. In addition, contemporary strategies take into account economic development with respect to environmental protection. The goal of this paper was to assess sustainable regional development in Poland, taking into account environmental and innovative activity indicators, as well as mobility and accessibility in remote areas. To recognize the effects of supporting sustainable development, the evaluation was carried out considering the indicators from the Statistics Poland platform, concerning 2011 and 2021, and related them to economic development, the environment, mobility and accessibility of 16 regions. Comparing results obtained with the K-means clustering method with those obtained with the partitioning around medoids method, it was possible to verify, with greater reliability, the migration of regions into different clusters. Results showed that development of all the regions was significant yet highly disproportionate, thus highlighting the consolidated presence of dynamically growing regions versus peripheries, which means further regional polarization. An educational cross-sectorial approach can play a crucial role in promoting green pro-innovative development.
Spatiotemporal Variation in and Responses of the NDVI to Climate in Western Ordos and Eastern Alxa
Authors: Zhang Hui , Guo Jinting , Li Xiaotian , Liu Yajie , Wang Tiejuan
Published: March 2023

Vegetation is an important component of the terrestrial ecosystem, and studying the rules of vegetation change and its driving factors is helpful to strengthen the ecological protection and sustainable development of regional vegetation. This study analyzes the changes in Normalized Difference Vegetation Index (NDVI) and its response to climate factors in the five regions of western Ordos and eastern Alxa in China between 2000 and 2020. The MODIS NDVI and meteorological data from 2000 to 2020 was used and the ordinary least squares, trend analysis, and correlation analysis methods were analyzed. The NDVI in this region shows spatial differentiation and is high in the east and low in the west. The overall NDVI has shown a significant increasing trend (p < 0.01), and the slope value of the rate of change also shows that the NDVI in 98.17% of the area is increasing. On a temporal scale, NDVI had a significant positive correlation with precipitation (p < 0.01), but no significant correlation with temperature changes. On a spatial scale, NDVI was positively correlated with precipitation, which accounted for 95.57% of spatial changes, of which a significant positive correlation accounted for 34.99% (p < 0.05). Meanwhile, the temperature and NDVI were negatively correlated but not significantly. A positive correlation accounted for 45.95% of the change, but the insignificant negative correlation accounted for 54.05%. Therefore, comprehensive analysis showed that precipitation played a leading role in the NDVI in the study area. The results are helpful to study the driving mechanism of vegetation growth and provide reference for vegetation protection in regions of western Ordos and eastern Alxa of Inner Mongolia, China.
Dynamic Vehicle Routing Problem with Fuzzy Customer Response
Authors: Kim Gitae
Published: March 2023

This paper proposes a dynamic vehicle routing problem (DVRP) model with fuzzy customer responses and suggests optimal routing strategies. Most DVRP studies have focused on how to create a new route upon the occurrence of dynamic situations such as unexpected demands. However, the customer responses have received little attention. When a pop-up demand is added to one of the planned routes, the service for some optimally planned demands may be delayed. Customers may file complaints or cancel their orders as a result of the delays. As a result, the customer response has a significant impact on current profits as well as future demands. In this research, we consider the customer response in DVRP and address it with a fuzzy number. Changing distances or defining time windows can resolve the problem of customer response. The customer responses are represented by a fuzzy rule. The new routing strategy provides the viability to reduce customer complaints and avoid losing potential customers.
Research on Demand Price Elasticity Based on Expressway ETC Data: A Case Study of Shanghai, China
Authors: Li Yunyi , Shao Minhua , Sun Lijun , Wang Xinmiao , Song Shizhao
Published: March 2023

The research on price elasticity of demand, especially in the field of transportation, has high theoretical and application value. Based on the perspective of price elasticity of demand, the study presents the impact of adjusting expressway rates on the traffic flow of cars with seven seats or less. The data are from the measured data of the Shanghai expressway Electronic Toll Collection (ETC) from 2019 to 2020. In order to eliminate the impact of the surge of ETC users in 2019 on the results, Empirical Mode Decomposition (EMD) is used to optimize the data. The research shows that the price elasticity of demand will increase with the increase in charge amount (distance).
Suitability Evaluation of Human Settlements Using a Global Sensitivity Analysis Method: A Case Study in China
Authors: Wu Feifei , Yang Xiaohua , Lian Bing , Wang Yan , Kang Jing
Published: March 2023

The suitability evaluation of human settlements over time and space is essential to track potential challenges towards suitable human settlements and provide references for policy-makers. This study established a theoretical framework of human settlements based on the nature, human, economy, society, and residence subsystems. Evaluation indicators were determined with the consideration of the coupling effect among subsystems. Based on the extended Fourier amplitude sensitivity test algorithm, the global sensitivity analysis was used to determine the weights of indicators. The human settlement suitability was evaluated in 30 provinces of China between 2000 and 2016. The findings were as follows: (1) human settlement suitability index (HSSI) values increased significantly in all 30 provinces from 2000 to 2016. The suitability index of the residence subsystem in China exhibited the fastest growth, followed by the society and economy subsystems. (2) HSSI in eastern provinces with a developed economy was higher than that in western provinces with an underdeveloped economy. In contrast, the growth rate of HSSI in eastern provinces was significantly higher than that in western provinces. (3) The inter-provincial difference in HSSI narrowed down from 2000 to 2016. For subsystems, the difference narrowed down for the residence system, whereas it widened for the economy system. (4) The suitability of the nature subsystem has become a limiting factor for the improvement of human settlement suitability, especially in economically developed provinces, such as Beijing, Shanghai, and Guangdong. The results can be helpful to support decision-making and policy for improving the quality of human settlements in a broad nature, human, economy, society, and residence context.
Learning and Well-Being in Multilingual Adolescents with Italian as L2: A Comparison with Monolingual Peers with and without a Learning Disorder
Authors: Bettoni Roberta , Vernice Mirta , Tironi Marta , Lombardi Elisabetta , Offredi Ilaria , Giorgetti Marisa , Lorusso Maria Luisa , Sarti Daniela , Traficante Daniela
Published: March 2023

The current exploratory study aimed to offer a description of the learning skills and well-being of multilingual adolescents with Italian as L2, a population regarded as vulnerable with respect to their academic achievements and psychosocial profile. We compared the performance of L2 participants with that of their monolingual peers with and without Specific Learning Disorders on a range of tests and questionnaires to define their learning skills and well-being within the school context. Results confirm greater reading difficulties in the L2 group compared to monolingual peers with Specific Learning Disorders. This pilot study offers one of the first investigations into the learning skills and well-being of a scarcely studied population, namely L2 adolescents. Additionally, it discusses practices that can be implemented within the classroom to promote inclusion.
Evaluation of the Spirituality of Village Committees on Integrated Risk Governance of Agricultural Drought: A Case Study in Xindu District, Hebei Province, China
Authors: Jiang Yao , Wu Yaoyao , Guo Hao , Zhang Guoming , Wang Jingai
Published: March 2023

The spirituality of stakeholders in cases of drought has gained significant attention in the field of integrated risk governance of agricultural drought. In this paper, based on a field survey and 30 drought response actions in China, we established an indicator system and quantitative model based on concentration and willpower (spirituality, abbreviated as S), considering the aspects of responsibility (R), enterprise (E), and devotion (D) to evaluate the spirituality of the village committee of Xindu District, Hebei Province. We aimed to develop a new method for the quantitative research of multi-stakeholders’ concentration and willpower and to provide a more scientific reference for the formation of consilience in the process of improving risk governance capability. The main conclusions are as follows: (1) Condensed connotations of spirituality focus on expressing the spirit state of each stakeholder, which is the embodiment of the stakeholder’s concentration and willpower in the consilience system. (2) An evaluation framework of “deeds information excavating → stakeholder-oriented survey → grading and classification” is formed. Based on Chinese traditional cultural backgrounds and administrative system characteristics, the evaluation indicator system and model of spirituality are constructed and will further promote the visualization and quantification of spirituality research. (3) The spirituality index (S) of village committees on integrated risk governance of drought presents a trend of normal distribution, and the average value of all secondary indices is R > E > D. The mean value of R is 0.93 and the sample range is 0.49. D has the lowest mean value, with a range of 0.37. (4) There is a regional difference in the average values of spirituality index (S) as follows: “plain area > mountain area > hilly area”, from the perspective of geomorphic units, and “high-income area > middle-income area > low-income area”, from the perspective of the regional economy.
Heuristic Technique for the Search of Interception Trajectories to Asteroids with the Use of Solar Sails
Authors: Meireles Lucas Gouvêa , Prado Antônio Fernando Bertachini de Almeida , de Melo Cristiano Fiorilo , Pereira Maria Cecília
Published: March 2023

With the advances of space-exploration technologies, a long-lasting concern is finally being addressed: the deflection of potentially hazardous objects (PHOs). Most recently, the first mission of this kind was launched by NASA—the Double Asteroid Redirection Test (DART). Nevertheless, it is estimated that a great number of these PHOs are unattainable by means of current chemical propulsion systems. With that in mind, this study proposes the development of a heuristic technique for the search of interception trajectories with the use of solar sails and its application in determining a set of possible trajectories to intercept hazardous asteroids. As a case study, a hybrid mission inspired by the DART mission is proposed by using a solar sail as means of propulsion after the initial chemical combustion. The dynamics consider a model of the solar radiation pressure acceleration as a function of the orientation of the sail. In turn, the orientation is defined by the application of the developed heuristic technique with the goal of defining alternative trajectories compared to the original mission. These trajectories result in different impact conditions and mission durations. Although the use of solar sails breaks the symmetry in the solutions, the results obtained offer the possibility of fuel economy or even better deflection results by the achievement of greater impact energy with the hazardous objects.
A New Detection Function Model for Distance Sampling Based on the Burr XII Model
Authors: Alanzi Ayed R. A. , Jamal Farrukh , Tahir Muhammad H. , Chesneau Christophe , Kanwal Sana , Sami Waqas
Published: March 2023

One of the most used techniques for determining animal abundance is distance sampling. The distance sampling framework depends on the idea of a detection function, and a number of options have been suggested. In this paper, we provide a new flexible parametric model based on the Burr XII distribution. To be more specific, we use the survival function of the Burr XII distribution for novel purposes in this context. The proposed model is appealing because it meets all of the requirements for a reliable detection function model, such as being monotonically decreasing and having a shoulder at the origin. It also has the features of having various asymmetric properties and a heavy right tail, which are rare properties in this setting. In the first part, we provide its key characteristics, such as shapes and moments. Then, the inferential aspect of the model is investigated. The maximum likelihood estimation method is used to estimate the parameters in a data-fitting scenario. The estimates of population abundance are derived and compared with some existing parametric estimates. A simulation is run to assess how well the resulting estimates perform in comparison to other widely applied estimates from the literature. The model is then tested using two real-world data sets. Based on the famous goodness-of-fit statistics, we show that it is preferable to some of the well-established models.
Arsenic Soil Contamination and Its Effects on 5-Methylcytosine Levels in Onions and Arsenic Distribution and Speciation
Authors: Popov Marek , Kudrna Jiří , Lhotská Marie , Hnilička František , Tunklová Barbora , Zemanová Veronika , Kubeš Jan , Vachová Pavla , Česká Jana , Praus Lukáš , Štengl Karel , Krucký Jiří
Published: March 2023

Arsenic represents a serious health threat in localities with a high arsenic-polluted environment and can easily get into the human food chain through agronomy production in areas affected by arsenic contamination. Onion plants that were grown in controlled conditions in arsenic-contaminated soil (5, 10, and 20 ppm) were harvested 21 days after contamination. Arsenic levels (from 0.43 ± 0.03 µg g−1 to 1761.11 ± 101.84 µg g−1) in the onion samples were high in the roots and low in the bulbs and leaves, which is probably caused by a reduced ability of the onions to transport arsenic from roots to bulbs and leaves. Arsenic species As(V) and As(III) in As(V)-contaminated soil samples were represented strongly in favor of the As(III) species. This indicates the presence of arsenate reductase. Levels of 5-methylcytosine (5-mC) (from 5.41 ± 0.28% to 21.17 ± 1.33%) in the onion samples were also higher in the roots than in the bulbs and leaves. Microscopic sections of the roots were examined, and the most damage was found in the 10 ppm As variant. Photosynthetic parameters pointed to a significant decrease in photosynthetic apparatus activity and the deterioration of the physiological state of plants as arsenic content increased in the soil.
Release of Ammunition-Related Compounds from a Dutch Marine Dump Site
Authors: den Otter J. H. , Pröfrock D. , Bünning T. H. , Strehse J. S. , van der Heijden A. E. D. M. , Maser E.
Published: March 2023

After World War II, large amounts of ammunition were dumped in surface waters worldwide, potentially releasing harmful and toxic compounds to the environment. To study their degradation, ammunition items dumped in the Eastern Scheldt in The Netherlands were surfaced. Severe damage due to corrosion and leak paths through the casings were observed, making the explosives in the ammunition accessible to sea water. Using novel techniques, the concentrations of ammunition-related compounds in the surrounding seabed and in the seawater were analyzed at 15 different locations. In the direct vicinity of ammunition, elevated concentrations of ammunition-related compounds (both metals and organic substances) were found. Concentrations of energetic compounds ranged from below the limit of detection (LoD) up to the low two-digit ng/L range in water samples, and from below the LoD up to the one-digit ng/g dry weight range in sediment samples. Concentrations of metals were found up to the low microgram/L range in water and up the low ng/g dry weight in sediment. However, even though the water and sediment samples were collected as close to the ammunition items as possible, the concentrations of these compounds were low and, as far as available, no quality standards or limits were exceeded. The presence of fouling, the low solubility of the energetic compounds, and dilution by the high local water current were concluded to be the main causes for the absence of high concentrations of ammunition-related compounds. As a conclusion, these new analytical methods should be applied to continuously monitor the Eastern Scheldt munitions dump site.
High Diversity of Giardia duodenalis Assemblages and Sub-Assemblages in Asymptomatic School Children in Ibadan, Nigeria
Authors: Tijani Muyideen K. , Köster Pamela C. , Guadano-Procesi Isabel , George Imo S. , Abodunrin Elizabeth , Adeola Adedamola , Dashti Alejandro , Bailo Begoña , González-Barrio David , Carmena David
Published: March 2023

Giardia duodenalis is a significant contributor to the burden of diarrheal disease in sub-Saharan Africa. This study assesses the occurrence and molecular diversity of G. duodenalis and other intestinal parasites in apparently healthy children (n = 311) in Ibadan, Nigeria. Microscopy was used as a screening method and PCR and Sanger sequencing as confirmatory and genotyping methods, respectively. Haplotype analyses were performed to examine associations between genetic variants and epidemiological variables. At microscopy examination, G. duodenalis was the most prevalent parasite found (29.3%, 91/311; 95% CI: 24.3–34.7), followed by Entamoeba spp. (18.7%, 58/311; 14.5–23.4), Ascaris lumbricoides (1.3%, 4/311; 0.4–3.3), and Taenia sp. (0.3%, 1/311; 0.01–1.8). qPCR confirmed the presence of G. duodenalis in 76.9% (70/91) of the microscopy-positive samples. Of them, 65.9% (60/91) were successfully genotyped. Assemblage B (68.3%, 41/60) was more prevalent than assemblage A (28.3%, 17/60). Mixed A + B infections were identified in two samples (3.3%, 2/60). These facts, together with the absence of animal-adapted assemblages, suggest that human transmission of giardiasis was primarily anthroponotic. Efforts to control G. duodenalis (and other fecal-orally transmitted pathogens) should focus on providing safe drinking water and improving sanitation and personal hygiene practices.
Kerr–Schild Tetrads and the Nijenhuis Tensor
Authors: Maluf José Wadih , Carneiro Fernando Lessa , Ulhoa Sérgio , Da Rocha-Neto José Francisco
Published: March 2023

We write the Kerr–Schild tetrads in terms of the flat space–time tetrads and of a (1, 1) tensor Sμλ. This tensor can be considered as a projection operator, since it transforms (i) flat space–time tetrads into non-flat tetrads, and vice-versa, and (ii) the Minkowski space–time metric tensor into a non-flat metric tensor, and vice-versa. The Sμλ tensor and its inverse are constructed in terms of the standard null vector field lμ that defines the Kerr–Schild form of the metric tensor in general relativity, and that yields black holes and non-linear gravitational waves as solutions of the vacuum Einstein’s field equations. We demonstrate that the condition for the vanishing of the Ricci tensor obtained by Kerr and Schild, in empty space–time, is also a condition for the vanishing of the Nijenhuis tensor constructed out of Sμλ. Thus, a theory based on the Nijenhuis tensor yields an important class of solutions of the Einstein’s field equations, namely, black holes and non-linear gravitational waves. We also demonstrate that the present mathematical framework can easily admit modifications of the Newtonian potential that may explain the long range gravitational effects related to galaxy rotation curves.
Aspects of Quantum Gravity Phenomenology and Astrophysics
Authors: Dasgupta Arundhati , Fajardo-Montenegro José
Published: March 2023

With the discovery of gravitational waves, the search for the quantum of gravity, the graviton, is imminent. We discuss the current status of the bounds on graviton mass from experiments as well as the theoretical understanding of these particles. We provide an overview of current experiments in astrophysics such as the search for Hawking radiation in gamma-ray observations and neutrino detectors, which will also shed light on the existence of primordial black holes. Finally, the semiclassical corrections to the image of the event horizon are discussed.
IL-8 Secreted by Gastric Epithelial Cells Infected with Helicobacter pylori CagA Positive Strains Is a Chemoattractant for Epstein–Barr Virus Infected B Lymphocytes
Authors: Domínguez-Martínez Diana A. , Fontes-Lemus José I. , García-Regalado Alejandro , Juárez-Flores Ángel , Fuentes-Pananá Ezequiel M.
Published: March 2023

Helicobacter pylori and EBV are considered the main risk factors in developing gastric cancer. Both pathogens establish life-lasting infections and both are considered carcinogenic in humans. Different lines of evidence support that both pathogens cooperate to damage the gastric mucosa. Helicobacter pylori CagA positive virulent strains induce the gastric epithelial cells to secrete IL-8, which is a potent chemoattractant for neutrophils and one of the most important chemokines for the bacterium-induced chronic gastric inflammation. EBV is a lymphotropic virus that persists in memory B cells. The mechanism by which EBV reaches, infects and persists in the gastric epithelium is not presently understood. In this study, we assessed whether Helicobacter pylori infection would facilitate the chemoattraction of EBV-infected B lymphocytes. We identified IL-8 as a powerful chemoattractant for EBV-infected B lymphocytes, and CXCR2 as the main IL-8 receptor whose expression is induced by the EBV in infected B lymphocytes. The inhibition of expression and/or function of IL-8 and CXCR2 reduced the ERK1/2 and p38 MAPK signaling and the chemoattraction of EBV-infected B lymphocytes. We propose that IL-8 at least partially explains the arrival of EBV-infected B lymphocytes to the gastric mucosa, and that this illustrates a mechanism of interaction between Helicobacter pylori and EBV.
Virological Markers in Epstein–Barr Virus-Associated Diseases
Authors: Lupo Julien , Truffot Aurélie , Andreani Julien , Habib Mohammed , Epaulard Olivier , Morand Patrice , Germi Raphaële
Published: March 2023

Epstein–Barr virus (EBV) is an oncogenic virus infecting more than 95% of the world’s population. After primary infection—responsible for infectious mononucleosis in young adults—the virus persists lifelong in the infected host, especially in memory B cells. Viral persistence is usually without clinical consequences, although it can lead to EBV-associated cancers such as lymphoma or carcinoma. Recent reports also suggest a link between EBV infection and multiple sclerosis. In the absence of vaccines, research efforts have focused on virological markers applicable in clinical practice for the management of patients with EBV-associated diseases. Nasopharyngeal carcinoma is an EBV-associated malignancy for which serological and molecular markers are widely used in clinical practice. Measuring blood EBV DNA load is additionally, useful for preventing lymphoproliferative disorders in transplant patients, with this marker also being explored in various other EBV-associated lymphomas. New technologies based on next-generation sequencing offer the opportunity to explore other biomarkers such as the EBV DNA methylome, strain diversity, or viral miRNA. Here, we review the clinical utility of different virological markers in EBV-associated diseases. Indeed, evaluating existing or new markers in EBV-associated malignancies or immune-mediated inflammatory diseases triggered by EBV infection continues to be a challenge.
Immune Factors Drive Expression of SARS-CoV-2 Receptor Genes Amid Sexual Disparity
Authors: Vashisht Ashutosh , Ahluwalia Pankaj , Mondal Ashis K. , Singh Harmanpreet , Sahajpal Nikhil S. , Fulzele Sadanand , Kota Vamsi , Gahlay Gagandeep K. , Kolhe Ravindra
Published: March 2023

The emergence of COVID-19 has led to significant morbidity and mortality, with around seven million deaths worldwide as of February 2023. There are several risk factors such as age and sex that are associated with the development of severe symptoms due to COVID-19. There have been limited studies that have explored the role of sex differences in SARS-CoV-2 infection. As a result, there is an urgent need to identify molecular features associated with sex and COVID-19 pathogenesis to develop more effective interventions to combat the ongoing pandemic. To address this gap, we explored sex-specific molecular factors in both mouse and human datasets. The host immune targets such as TLR7, IRF7, IRF5, and IL6, which are involved in the immune response against viral infections, and the sex-specific targets such as AR and ESSR were taken to investigate any possible link with the SARS-CoV-2 host receptors ACE2 and TMPRSS2. For the mouse analysis, a single-cell RNA sequencing dataset was used, while bulk RNA-Seq datasets were used to analyze the human clinical data. Additional databases such as the Database of Transcription Start Sites (DBTS), STRING-DB, and the Swiss Regulon Portal were used for further analysis. We identified a 6-gene signature that showed differential expression in males and females. Additionally, this gene signature showed potential prognostic utility by differentiating ICU patients from non-ICU patients due to COVID-19. Our study highlights the importance of assessing sex differences in SARS-CoV-2 infection, which can assist in the optimal treatment and better vaccination strategies.
Pending Reorganization of Hantaviridae to Include Only Completely Sequenced Viruses: A Call to Action
Authors: Kuhn Jens H. , Bradfute Steven B. , Calisher Charles H. , Klempa Boris , Klingström Jonas , Laenen Lies , Palacios Gustavo , Schmaljohn Connie S. , Tischler Nicole D. , Maes Piet
Published: March 2023

The official classification of newly discovered or long-known unassigned viruses by the International Committee on Taxonomy of Viruses (ICTV) requires the deposition of coding-complete or -near-complete virus genome sequences in GenBank to fulfill a requirement of the taxonomic proposal (TaxoProp) process. However, this requirement is fairly new; thus, genomic sequence information is fragmented or absent for many already-classified viruses. As a result, taxon-wide modern phylogenetic analyses are often challenging, if not impossible. This problem is particularly eminent among viruses with segmented genomes, such as bunyavirals, which were frequently classified solely based on single-segment sequence information. To solve this issue for one bunyaviral family, Hantaviridae, we call on the community to provide additional sequence information for incompletely sequenced classified viruses by mid-June 2023. Such sequence information may be sufficient to prevent their possible declassification during the ongoing efforts to establish a coherent, consistent, and evolution-based hantavirid taxonomy.
Enhancement of Vaccine-Induced T-Cell Responses by PD-L1 Blockade in Calves
Authors: Okagawa Tomohiro , Konnai Satoru , Nakamura Hayato , Ganbaatar Otgontuya , Sajiki Yamato , Watari Kei , Noda Haruka , Honma Mitsuru , Kato Yukinari , Suzuki Yasuhiko , Maekawa Naoya , Murata Shiro , Ohashi Kazuhiko
Published: March 2023

Interactions between programmed death 1 (PD-1) and PD-ligand 1 (PD-L1) cause functional exhaustion of T cells by inducing inhibitory signals, thereby attenuating effector functions of T cells. We have developed an anti-bovine PD-L1 blocking antibody (Ab) and have demonstrated that blockade of the interaction between PD-1 and PD-L1 reactivates T-cell responses in cattle. In the present study, we examined the potential utility of PD-1/PD-L1-targeted immunotherapy in enhancing T-cell responses to vaccination. Calves were inoculated with a hexavalent live-attenuated viral vaccine against bovine respiratory infections in combination with treatment with an anti-PD-L1 Ab. The expression kinetics of PD-1 in T cells and T-cell responses to viral antigens were measured before and after vaccination to evaluate the adjuvant effect of anti-PD-L1 Ab. PD-1 expression was upregulated in vaccinated calves after the administration of a booster vaccination. The activation status of CD4+, CD8+, and γδTCR+ T cells was enhanced by the combination of vaccination and PD-L1 blockade. In addition, IFN-γ responses to viral antigens were increased following combinatorial vaccination with PD-L1 blockade. In conclusion, the blockade of the PD-1/PD-L1 interaction enhances T-cell responses induced by vaccination in cattle, indicating the potential utility of anti-PD-L1 Ab in improving the efficacy of current vaccination programs.
Could Prior COVID-19 Affect the Neutralizing Antibody after the Third BNT162b2 Booster Dose: A Longitudinal Study
Authors: Erdem Mustafa Genco , Unlu Ozge , Buber Suleyman , Demirci Mehmet , Kocazeybek Bekir Sami
Published: March 2023

Vaccination is an essential public health measure for preventing the spread of illness during this continuing COVID-19 epidemic. The immune response developed by the host or the continuation of the immunological response caused by vaccination is crucial since it might alter the epidemic’s prognosis. In our study, we aimed to determine the titers of anti-S-RBD antibody and surrogate neutralizing antibody (snAb) formed before and after the third dose of the BNT162b2 vaccination (on the 15th, 60th, and 90th days) in healthy adults who did not have any comorbidity either with or without prior SARS-CoV-2 infection. In this longitudinal prospective study, 300 healthy persons were randomly included between January and February 2022, following two doses of BNT162b2 immunization and before a third dosage. Blood was drawn from the peripheral veins. SARS-CoV-2 NCP IgG and anti-S-RBD IgG levels were detected by the CMIA method, and a surrogate neutralizing antibody was seen by the ELISA method. Our study included 154 (51.3%) female and 146 (48.7%) male (total 300) participants. The participants’ median age was 32.5 (IQR:24–38). It was discovered that 208 individuals (69.3%) had never been infected with SARS-CoV-2, whereas 92 participants (30.7%) had SARS-CoV-2 infections in the past. Anti-S-RBD IgG and nAb IH% levels increased 5.94- and 1.26-fold on day 15, 3.63- and 1.22-fold on day 60, and 2.33- and 1.26-fold on day 90 after the third BNT162b2 vaccine dosage compared to pre-vaccination values (Day 0). In addition, the decrease in anti-S-RBD IgG levels on the 60th and 90th days was significantly different in the group without prior SARS-CoV-2 infection compared to the group with past SARS-CoV-2 infection (p < 0.05). In conclusion, it was observed that prior SARS-CoV-2 infection and the third BNT162b2 vaccine dose led to a lower decrease in both nAb and anti-S-RBD IgG levels. To evaluate the vaccine’s effectiveness and update immunization programs, however, it is necessary to perform multicenter, longer-term, and comprehensive investigations on healthy individuals without immune response issues, as there are still circulating variants.