bluuebunny/crossref_metadata_2025 huggingface dataset:
Pole-Like Object Extraction and Pole-Aided GNSS/IMU/LiDAR-SLAM System in Urban Area
Authors: Liu Tianyi , Chang Le , Niu Xiaoji , Liu Jingnan
Published: December 2020

Vision-based sensors such as LiDAR (Light Detection and Ranging) are adopted in the SLAM (Simultaneous Localization and Mapping) system. In the 16-beam LiDAR aided SLAM system, due to the difficulty of object detection by sparse laser data, neither the grid-based nor feature point-based solution can avoid the interference of moving objects. In an urban environment, the pole-like objects are common, invariant and have distinguishing characteristics. Therefore, it is suitable to bring more robust and reliable positioning results as auxiliary information in the process of vehicle positioning and navigation. In this work, we proposed a scheme of a SLAM system using a GNSS (Global Navigation Satellite System), IMU (Inertial Measurement Unit) and LiDAR sensor using the position of pole-like objects as the features for SLAM. The scheme combines a traditional preprocessing method and a small scale artificial neural network to extract the pole-like objects in environment. Firstly, the threshold-based method is used to extract the pole-like object candidates from the point cloud, and then, the neural network is applied for training and inference to obtain pole-like objects. The result shows that the accuracy and recall rate are sufficient to provide stable observation for the following SLAM process. After extracting the poles from the LiDAR point cloud, their coordinates are added to the feature map, and the nonlinear optimization of the front end is carried out by utilizing the distance constraints corresponding to the pole coordinates; then, the heading angle and horizontal plane translation are estimated. The ground feature points are used to enhance the elevation, pitch and roll angle accuracy. The performance of the proposed navigation system is evaluated through field experiments by checking the position drift and attitude errors during multiple two-min mimic GNSS outages without additional IMU motion constrain such as NHC (Nonholonomic Constrain). The experimental results show that the performance of the proposed scheme is superior to that of the conventional feature point grid-based SLAM with the same back end, especially in congested crossroads where slow-moving vehicles are surrounded and pole-like objects are rich in the environment. The mean plane position error during two-min GNSS outages was reduced by 38.5%, and the root mean square error was reduced by 35.3%. Therefore, the proposed pole-like feature-based GNSS/IMU/LiDAR SLAM system can fuse condensed information from those sensors effectively to mitigate positioning and orientation errors, even in a short-time GNSS denied environment.
Characterization and Neural Modeling of a Microwave Gas Sensor for Oxygen Detection Aimed at Healthcare Applications
Authors: Marinković Zlatica , Gugliandolo Giovanni , Latino Mariangela , Campobello Giuseppe , Crupi Giovanni , Donato Nicola
Published: December 2020

The studied sensor consists of a microstrip interdigital capacitor covered by a gas sensing layer made of titanium dioxide (TiO2). To explore the gas sensing properties of the developed sensor, oxygen detection is considered as a case study. The sensor is electrically characterized using the complex scattering parameters measured with a vector network analyzer (VNA). The experimental investigation is performed over a frequency range of 1.5 GHz to 2.9 GHz by placing the sensor inside a polytetrafluoroethylene (PTFE) test chamber with a binary gas mixture composed of oxygen and nitrogen. The frequency-dependent response of the sensor is investigated in detail and further modelled using an artificial neural network (ANN) approach. The proposed modelling procedure allows mimicking the measured sensor performance over the whole range of oxygen concentration, going from 0% to 100%, and predicting the behavior of the resonant frequencies that can be used as sensing parameters.
Sustainability Issues in the Traditional Cashmere Supply Chain: Empirical Evidence from Kashmir, India
Authors: Ishrat Sheikh I. , Grigg Nigel P. , Bezuidenhout Carel N. , Jayamaha Nihal P.
Published: December 2020

Considering the emerging global markets for the consumption of cashmere products, current sustainability issues prevailing in the traditional cashmere industry are explored in this study. To get a deeper understanding of the sustainability concerns in the cashmere industry, it is important to understand the cashmere supply chain operations to uncover the key sustainability issues prevalent in the present-day traditional cashmere industry. For this, a single case study was conducted in Kashmir, India using qualitative approaches. Data collection was carried out using semi-structured interviews, observations, cashmere retailer websites and documentary evidence. Due to the impact of mechanization and lack of industry standards, the research findings indicate deteriorating socio-economic conditions of the artisans; especially, women spinners and weavers. Mechanization promotes economic sustainability for the manufacturers and retailers which helps them strengthen their market base. However, with this, artisan communities are rendered jobless who are dependent on their manual skills for sustenance as they have limited alternate revenue generation options. Moreover, the lack of motivation among the artisans to use institutional support further escalates sustainability concerns in the traditional craft industry.
Shear Behavior of a Reinforced Concrete Frame Retrofitted with a Hinged Steel Damping System
Authors: Yun Hyun-Do , Kim Sun-Woong , Park Wan-Shin , Kim Sun-Woo
Published: December 2020

The purpose of this study was to experimentally evaluate the effect of a hinged steel damping system on the shear behavior of a nonductile reinforced concrete frame with an opening. For the experimental test, a total of three full-scale reinforced concrete frame specimens were planned, based on the “no retrofitting” (NR) specimens with non-seismic details. The main research questions were whether the hinged steel damping system is reinforced and whether torsion springs are installed in the hinged steel damping system. From the results of the experiment, the hinged steel damping system (DR specimen) was found to be effective in seismic retrofitting, while isolating the opening of the reinforced concrete (RC) frame, and the torsion spring installed at the hinged connection (DSR specimen) was evaluated to be effective in controlling the amount of deformation of the upper and lower dampers. The strength, stiffness, and energy dissipation capacity of the DSR specimen were slightly improved compared to the DR specimen, and it was confirmed that stress redistribution was induced by the rotational stiffness of the torsion spring installed in the hinge connection between the upper and lower frames.
Socio-Economic Determinants of Small Family Farms’ Resilience in Selected Central and Eastern European Countries
Authors: Borychowski Michał , Stępień Sebastian , Polcyn Jan , Tošović-Stevanović Aleksandra , Ćalović Dragan , Lalić Goran , Žuža Milena
Published: December 2020

We investigated the resilience of small-scale family farms because of the contemporary importance of both the farms’ resilience and the role of these farms in five countries of Central and Eastern Europe. The authors addressed a research gap concerning cross-sectional research on the resilience of farms by combining determinants from various fields. Thus, the primary goal of this article was to identify microeconomic and political factors and links to markets that affect the resilience of small-scale family farms in Lithuania, Moldova, Poland, Romania and Serbia. Using a database of over 3500 farms, the resilience of the farms was calculated, and then the impact of selected factors on that resilience was determined. The research showed that the production scale was the key determinant of the resilience of farms. To achieve higher benefits, increasing the production should be combined with strengthening the market integration of agricultural producers. The position of the producer in the food supply chain determined the income situation of the farm (economic stability). This shaped the quality of life of the family members (social stability). Identifying the effects of those dependencies may provide recommendations for the policy of supporting small-scale family farms in the analysed countries.
Is There Any Relation between the Architectural Characteristics of Kindergartens and the Spread of the New Coronavirus in Them?—A Case Study of Slovenia
Authors: Lovec Vesna , Premrov Miroslav , Žegarac Leskovar Vesna
Published: December 2020

The COVID-19 era is bringing changes to different parts of everyday life, redefining what people used to consider normal. As the world deals with this highly contagious disease, the issue of the built environment, buildings, their architecture and possible relations among their characteristics and the spread of the virus remains unclear. Preschool and school education is an essential part of society. However, with the spread of COVID-19, kindergartens and schools keep on partly or fully closing and reopening, trying to provide a safe and healthy environment for children. Instructions and recommendations from different experts and organisations worldwide were announced in terms of how to adjust the functioning of kindergartens in conditions of the uncontrolled spread of COVID-19. The measures include organisational and hygiene measures. Organisational measures are closely related to the architectural design of a building. At this point, the main question of this research was raised: is there any relation between the architectural characteristics of kindergartens and the spread of the new coronavirus in them? The research examined the architectural characteristics of kindergartens in Slovenia with reported COVID-19 cases among staff or children.
Key Competences, Education for Sustainable Development and Strategies for the Development of 21st Century Skills. A Systematic Literature Review
Authors: González-Salamanca Juan Carlos , Agudelo Olga Lucía , Salinas Jesús
Published: December 2020

Skills needed to be successful in the world have changed, and there is a gap between those learned at school and those required to function at work and in society. A broader range of skills is required to learn, communicate, collaborate, and solve problems in digital environments. Twenty-first century skills have been identified by UNESCO, OECD, and others as competences required for a sustainable future of the knowledge society. The aim was to learn the design principles involved in the incorporation of these skills into the curriculum, find out possible ways to teach and assess them, and examine how this process could be personalized using Information and Communications Technology (ICT). A literature review was carried out through a qualitative metasynthesis, which identified 43 studies that met the inclusion criteria. From the in-depth analysis, it can be seen that although the incorporation of 21st century skills into the curriculum, teaching methodologies, and the use of ICT are all recurrent themes, there is still a need for further research into the design and implementation of new instruments for assessment and the ways in which the teaching–learning process can be personalized.
Online Teaching and Learning in Higher Education during the Coronavirus Pandemic: Students’ Perspective
Authors: Coman Claudiu , Țîru Laurențiu Gabriel , Meseșan-Schmitz Luiza , Stanciu Carmen , Bularca Maria Cristina
Published: December 2020

The research focuses on identifying the way in which Romanian universities managed to provide knowledge during the Coronavirus pandemic, when, in a very short time, universities had to adapt the educational process for exclusively online teaching and learning. In this regard, we analyzed students’ perception regarding online learning, their capacity to assimilate information, and the use of E-learning platforms. An online survey based on a semi-structured questionnaire was conducted. Data was collected from 762 students from two of the largest Romanian universities. The results of the research revealed that higher education institutions in Romania were not prepared for exclusively online learning. Thus, the advantages of online learning identified in other studies seem to diminish in value, while disadvantages become more prominent. The hierarchy of problems that arise in online learning changes in the context of the crisis caused by the pandemic. Technical issues are the most important, followed by teachers’ lack of technical skills and their teaching style improperly adapted to the online environment. However, the last place was assigned by students to the lack of interaction with teachers or poor communication with them. Based on these findings, research implications for universities and researchers are discussed.
The Role of Citizen Science in Sustainable Agriculture
Authors: Mourad Khaldoon A. , Hosseini Seyyed Hasan , Avery Helen
Published: December 2020

Farmers know much more than we think, and they are keen to improve their knowledge in order to improve their farms and increase their income. On the other hand, decision-makers, organizations, and researchers are increasing their use of citizen volunteers to strengthen their outcomes, enhance project implementation, and approach ecosystem sustainability. This paper assesses the role of citizen science relating to agricultural practices and covers citizen science literature on agriculture and farmers’ participation during the period 2007–2019. The literature was examined for the role of citizen science in supporting sustainable agriculture activities, pointing to opportunities, challenges, and recommendations. The study identified the following gaps: insufficient attention to (1) long-term capacity building and dialogue between academics and farming communities; (2) developing countries in the global South and smallholders; (3) agriculture trading and marketing; (4) the rationales of selecting target groups; (5) contributing to accelerated sustainability transitions. The main aim of the research projects reviewed in this study tended to focus on the research outcomes from an academic perspective, not sustainable solutions in practice or sustainability in general. More research is needed to address these gaps and to widen the benefits of citizen science in sustainable agricultural practices.
Understanding the Key Quality Factors in Construction Projects—A Systematic Literature Review
Authors: Wawak Sławomir , Ljevo Žanesa , Vukomanović Mladen
Published: December 2020

Project management frameworks describe the preferred approaches to project quality management, as well as applicable methods and tools. Despite this, quality problems in the construction project are still widespread. This study aimed to identify crucial quality-related factors in construction project management and find relations between them, to help researchers and project managers better respond to quality issues. A systematic literature review (SLR) was used to identify previous studies on quality-related factors. Literature review and further quantitative analysis revealed that quality-related factors are related to three categories: Quality of project process, quality of organisational processes, and quality of results (products), which together create the quality of the whole construction project. The results highlight quality-related factors (14 related to the quality of processes, 6 to quality of an organisation, and 13 to quality of products) that should be taken into account in further research, as well as planning and executing construction projects. Their inclusion at the planning stage should help project managers, sponsors, and steering committees avoid or minimise quality-related problems. Moreover, this study sheds an interesting light on quality. We found that the quality of processes and quality of an organisation has precedence over the final product quality. Based on the results of the study, structural equation modelling (SEM) was used to create a null model that will be the starting point for further research in the construction enterprises.
Plastic Bottle Cap Recycling—Characterization of Recyclate Composition and Opportunities for Design for Circularity
Authors: Gall Markus , Schweighuber Andrea , Buchberger Wolfgang , W. Lang Reinhold
Published: December 2020

In line with efforts to create a circular economy of plastics, recent EU legislation is strengthening plastic bottle recycling by ambitious separate collection targets and mandatory recycled content obligations. Furthermore, explicit design requirements on the caps of bottles and composite beverage packaging have been introduced. These caps are typically made of polyethylene or polypropylene and often contain additives such as slip agents and anti-statics. Commercially available bottle cap recyclates (BCRs) as well as specifically formulated model compounds were analyzed in terms of composition by means of infrared spectroscopy, differential scanning calorimetry, and high-performance liquid chromatography. Their composition was found to be heterogeneous due to polyolefin cross-contamination, directly reflecting the diversity of cap materials present in the market. Slip agent legacy additives originating from the initial use phase were found and quantified in both commercial and model cap recyclates. This highlights the opportunity for redesigning plastic bottle caps not only in response to regulatory requirements, but to pursue a more comprehensive strategy of product design for circularity. By including considerations of polymer resin and additive choice in cap manufacturing, more homogeneous waste streams could be derived from plastic bottle cap recycling, enabling recycling into more demanding and valuable applications.
International Collaboration in the Field of Environmental Protection: Trend Analysis and COVID-19 Implications
Authors: Chernysh Yelizaveta , Roubík Hynek
Published: December 2020

This paper focuses on the analysis of current cooperation trends in environmental protection research. A unified system of interrelations between research methods in the field of implementation of the bibliometric approach to the review of international cooperation in the field of environmental protection taking into account the consequences of the COVID-2019 pandemic was formed. To form a unified visualization of the analyzed bibliometric data, a special software product VOSViewer was used. Five clusters were defined: green—international cooperation for assessing risks to public health, in particular in the field of biosafety and the spread of social infections, with a focus on COVID-19, in 2019 and 2020; yellow—describes the related interaction between other clusters in the field of national and international mechanisms of cooperation in the regulation of greenhouse gas emissions and climate change; blue—brings together research areas in the field of economics of environmental management and control. The situation concerning the impact of the COVID-2019 pandemic is ambiguous, and it is crucial to recognize that this is a long-term period of impact, not only directly on public health but also due to economic and social constraints, as quarantine activities cause a chain of socio-economic crises. The problems of the environmental and economic spread of COVID-19 on various human activities and the environment require the development of this topic and the formation of a new cluster of interactions due to the wave dynamics of disease in the future. Broad cooperation and collaboration is proposed to address the challenges and accelerate sustainable development in Europe. A diagram of the main cooperation programs has been created, illustrating the overlap of the entire field, from basic research to the market. Further analytical studies will examine the effectiveness of cross-analysis using various scientometric databases to form an integrated approach to the new realities of quarantine activities.
Supporting Better Decision-Making: A Combined Grey Model and Data Envelopment Analysis for Efficiency Evaluation in E-Commerce Marketplaces
Authors: Wang Chia-Nan , Dang Thanh-Tuan , Nguyen Ngoc-Ai-Thy , Le Thi-Thu-Hong
Published: December 2020

E-commerce has become an integral part of businesses for decades in the modern world, and this has been exceptionally speeded up during the coronavirus era. To help businesses understand their current and future performance, which can help them survive and thrive in the world of e-commerce, this paper proposes a hybrid approach that conducts performance prediction and evaluation of the e-commerce industry by combining the Grey model, i.e., GM (1, 1) and data envelopment analysis, i.e., the Malmquist-I-C model. For each e-commerce company, GM (1, 1) is applied to predict future values for the period 2020–2022 and Malmquist-I-C is applied to calculate the efficiency score based on output variables such as revenue and gross profit and input variables such as assets, liabilities, and equity. The top 10 e-commerce companies in the US market are used to demonstrate model effectiveness. For the entire research period of 2016–2022, the most productive e-commerce marketplace on average was eBay, followed by Best Buy and Lowe’s; meanwhile, Groupon was the worst-performing e-commerce business during the studied period. Moreover, as most e-commerce companies have progressed in technological development, the results show that the determinants for productivity growth are the technical efficiency change indexes. That means, although focusing on technology development is the key to e-commerce success, companies should make better efforts to maximize their resources such as labor, material and equipment supplies, and capital. This paper offers decision-makers significant material for evaluating and improving their business performance.
Fostering Trust and Commitment in Complex Project Networks through Dedicated Investment in Partnership Management
Authors: Shin Nina , Yoo Jung-Sang , Kwon Ik-Whan G.
Published: December 2020

An absence of trust among partners can magnify the risk in a complex project by increasing behavioural uncertainty. Partnership trust can effectively substitute for control, reducing variability of outcomes and increasing value-adding strategic collaboration. It is introduced as strategic countermeasures against risks associated with project complexity that can only be achieved with commitment from all partners. This research conceptualises partnership trust on four dimensions and investigates the roles of dedicated investment and information sharing in partnership trust–commitment. The complexity of trust management is further highlighted in an exploration of the importance of the exchange relationship environment.
Agroforestry in the Andean Araucanía: An Experience of Agroecological Transition with Women from Cherquén in Southern Chile
Authors: Peredo Parada Santiago , Barrera Claudia , Burbi Sara , Rocha Daniela
Published: December 2020

Agroforestry is a practice used for the establishment of integrated production systems as an economic alternative. In Chile, the most significant experiences have been developed with rainfed farmers in the central zone, where the arboreal component is the predominant one. This study analyses the agroecological transition process of a group of women from the Andean foothills of southern Chile in the establishment of an agroforestry system based on rosehip. The field work was developed in 4 stages: (1) problem survey and definition of strategy; (2) identification of an alternative market; (3) perception of the data collection work and; (4) implementation of a demonstration unit; which included (a) workshops and meetings for discussion, reflection, and feedback on what had been done and to agree on the actions to be implemented; and (b) the development of different activities to implement the actions agreed in the workshops and meetings. The results of this research show that agroecological projects open doors to the participation, visibility, and valorization of women’s work while moving towards sustainable agroforestry systems integrated into the landscape.
Thermo-Environmental Assessment of a Heated Venlo-Type Greenhouse in the Yangtze River Delta Region
Authors: Odhiambo Morice R. O. , Abbas Adnan , Wang Xiaochan , Elahi Ehsan
Published: December 2020

Accurate evaluation of microclimate conditions in a greenhouse can assist producers to manage crop production and designers to optimize climate control systems. An assessment of the variable thermo-environmental behavior of a heated Venlo-type greenhouse under the influence of naturally changing climate conditions in the Yangtze River Delta region was undertaken. A three-dimensional transient computational fluid dynamics (CFD) model was developed to analyze the airflow pattern and dynamic distribution of temperature and humidity inside the greenhouse. Validation of the numerical model showed a satisfactory agreement between measured and simulated values of air velocity, temperature, and absolute humidity, with mean hourly air temperature mean absolute error (MAE) and root mean square error (RMSE) values of 7.7% and 7.9%, respectively, and mean hourly air humidity MAE and RMSE values of 16.18% and 16.42%, respectively. Simulation results demonstrated that the airflow pattern shaped the distribution of temperature and absolute humidity, and homogeneity of both variables was prevalent inside the greenhouse. These results could be adopted by growers and designers in the Yangtze River Delta region and other sub-tropical climatic regions to improve crop production and optimize climate control systems.
BIM for Healthy Buildings: An Integrated Approach of Architectural Design based on IAQ Prediction
Authors: D’Amico Alessandro , Bergonzoni Giacomo , Pini Agnese , Currà Edoardo
Published: December 2020

The relationship between users and the built environment represents a fundamental aspect of health. The factors that define the properties linked to health and well-being are increasingly becoming part of building design. In these terms, building information modelling (BIM) and BIM-based performance simulation take on a priority role. Among the key features for the design of Healthy Buildings, indoor air quality (IAQ) plays a central role. There are numerous indoor pollutants with significant health effects; volatile organic compounds (VOCs) are to be mentioned among these. The paper presents the proposal of an integrated workflow in the BIM process for the check and control of VOC emissions from building materials and their concentration in confined environments. The workflow is developed through the systematisation of IAQ parameters for the open BIM standard, the integration in the BIM process of a numerical model for the prediction of the VOCs concentration in the indoor environment, and the development of model checkers for performance verification. The results show a good adhesion between the numerical model and the implementation in BIM, providing the designer with a rapid control instrument of IAQ in the various phases of the building design. The present study is the first development focused on TVOC, but implementable concerning other aspects of IAQ, as needed for the effectiveness of performance building-based design for health and wellness issues.
Relationship between Urban New Business Indexes and the Business Environment of Chinese Cities: A Study Based on Entropy-TOPSIS and a Gaussian Process Regression Model
Authors: Shi Yishao , Liu Danxuan
Published: December 2020

The interactive development of economic globalization, informatization, marketization, and urbanization has reshaped the urban commercial landscape and society, and poses new requirements for the business environment. New commerce forms that are based on information technology and electronic payment and integrate online and offline forms are growing rapidly in China. However, the relationship between new commerce forms and the business environment has not received sufficient academic attention. Using 29 major cities in China, this paper constructs a new business index system consisting of the following six sub-indexes: the characteristic hotels index, the Starbucks index, the Freshhema index, the concept bookstores index, the smart convenience stores index, and the healthcare and medical examination index. The entropy coupled with the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) method was used for quantitative evaluation of urban new business vitality. We found that the Freshhema index and smart convenient store index are the two most important evaluation factors. The relationship between the new business index and the business environment was examined through multiple linear regression (MLR) and Gaussian process regression (GPR) analysis. We found that the MLR is not a valid model, and instead, the nonlinear GPR model has good explanatory power for this relationship. The results show that human capital has a more important effect than the economic development level on business vitality. The rise and development of new commercial forms depend on the innovation and optimization of the business environment.
How Is Forest Landscape Restoration Being Implemented in Burkina Faso? Overview of Ongoing Initiatives
Authors: Vinceti Barbara , Valette Michel , Bougma Ali Lardia , Turillazzi Arturo
Published: December 2020

Land degradation affects a significant portion of the Earth’s ice-free land area and several countries have embraced the challenge of restoring large parts of their degraded lands. Success in these efforts depends on various factors, including the amount of resources invested, the technical capacity available and the degree of involvement of stakeholders. Burkina Faso has committed to restoring 5 Mha of degraded land by 2030. We identified 39 forest landscape restoration initiatives (FLR) in this country and interviewed their managers to obtain an overview of critical aspects and constraints that could orient future efforts. Our results show a recent growth of FLR initiatives, as most of the projects examined started in the last few years; however, the scale of implementation seems incompatible with country-level targets. Funding is coming mainly from international cooperation and this may lead to risks in long-term continuity and sustainability of FLR. Furthermore, FLR projects are carried out by a multitude of agencies, with local NGOs and associations as the main players; this finding highlights the need to coordinate ongoing efforts and flag challenges in tracking progress. Tree planting is common to most FLR initiatives examined, with aspects of quality and quantity of planting material available becoming critical in ensuring success; this raises the need to ensure farmers are well-trained in its collection and handling. Finally, more homogeneous approaches in monitoring across FLR initiatives should be adopted.
Chemometrics for Selection, Prediction, and Classification of Sustainable Solutions for Green Chemistry—A Review
Authors: Bystrzanowska Marta , Tobiszewski Marek
Published: December 2020

In this review, we present the applications of chemometric techniques for green and sustainable chemistry. The techniques, such as cluster analysis, principal component analysis, artificial neural networks, and multivariate ranking techniques, are applied for dealing with missing data, grouping or classification purposes, selection of green material, or processes. The areas of application are mainly finding sustainable solutions in terms of solvents, reagents, processes, or conditions of processes. Another important area is filling the data gaps in datasets to more fully characterize sustainable options. It is significant as many experiments are avoided, and the results are obtained with good approximation. Multivariate statistics are tools that support the application of quantitative structure–property relationships, a widely applied technique in green chemistry.
Zhang–Zhang Polynomials of Ribbons
Authors: He Bing-Hau , Chou Chien-Pin , Langner Johanna , Witek Henryk A.
Published: December 2020

We report a closed-form formula for the Zhang–Zhang polynomial (also known as ZZ polynomial or Clar covering polynomial) of an important class of elementary peri-condensed benzenoids Rbn1,n2,m1,m2, usually referred to as ribbons. A straightforward derivation is based on the recently developed interface theory of benzenoids [Langner and Witek, MATCH Commun. Math. Comput. Chem.2020, 84, 143–176]. The discovered formula provides compact expressions for various topological invariants of Rbn1,n2,m1,m2: the number of Kekulé structures, the number of Clar covers, its Clar number, and the number of Clar structures. The last two classes of elementary benzenoids, for which closed-form ZZ polynomial formulas remain to be found, are hexagonal flakes Ok,m,n and oblate rectangles Orm,n.
Absence of Spontaneous Spin Symmetry Breaking in 1D and 2D Quantum Ferromagnetic Systems with Bilinear and Biquadratic Exchange Interactions
Authors: Zivieri Roberto
Published: December 2020

Some measurements have shown that the second-order exchange interaction is non-negligible in ferromagnetic compounds whose microscopic interactions are described by means of half-odd integer quantum spins. In these spin systems the ground state is either ferromagnetic or antiferromagnetic when the bilinear exchange interaction is dominant. Instead, in ferromagnetic systems characterized by bilinear and biquadratic exchange interactions of comparable magnitude, the energy minimum occurs when spins are in a canting ground-state. To this aim, a one-dimensional (1D) quantum spin chain and a two-dimensional (2D) lattice of quantum spins subjected to periodic boundary conditions are modeled via the generalized quantum Heisenberg Hamiltonian containing, in addition to the isotropic and short-range bilinear exchange interaction of the Heisenberg type, a second-order interaction, the isotropic and short-range biquadratic exchange interaction between nearest-neighbors quantum spins. For these 1D and 2D quantum systems a generalization of the Mermin–Wagner–Hohenberg theorem (also known as Mermin–Wagner–Berezinksii or Coleman theorem) is given. It is demonstrated, by means of quantum statistical arguments, based on Bogoliubov’s inequality, that, at any finite temperature, (1) there is absence of long-range order and that (2) the law governing the vanishing of the order parameter is the same as in the bilinear case for both 1D and 2D quantum ferromagnetic systems. The physical implications of the absence of a spontaneous spin symmetry breaking in 1D spin chains and 2D spin lattices modeled via a generalized quantum Heisenberg Hamiltonian are discussed.
Testing CPT Symmetry with Neutral K Mesons: A Review
Authors: Di Domenico Antonio
Published: December 2020

The neutral kaon system is a very peculiar system that offers unique possibilities to perform precise tests of the CPT symmetry. The entanglement of neutral kaon pairs that are produced at a ϕ-factory opens up new ways and scenarios in order to test this fundamental discrete symmetry. In this paper, the results of the most recent and significant CPT tests are reviewed. Experiments have set stringent limits on the CPT-violating parameters of different phenomenological models, some of them associated to possible decoherence mechanisms or Lorentz symmetry violation which might be justified in a quantum gravity framework. The present results show no violation of CPT symmetry, while their accuracy in some cases reaches the interesting level at which–in the most optimistic scenarios–quantum gravity effects might show up.
A Conceptual Model for the Origin of the Cutoff Parameter in Exotic Compact Objects
Authors: Rojas Castillo Wilson Alexander , Arenas Salazar Jose Robel
Published: December 2020

A Black Hole (BH) is a spacetime region with a horizon and where geodesics converge to a singularity. At such a point, the gravitational field equations fail. As an alternative to the problem of the singularity arises the existence of Exotic Compact Objects (ECOs) that prevent the problem of the singularity through a transition phase of matter once it has crossed the horizon. ECOs are characterized by a closeness parameter or cutoff, ϵ, which measures the degree of compactness of the object. This parameter is established as the difference between the radius of the ECO’s surface and the gravitational radius. Thus, different values of ϵ correspond to different types of ECOs. If ϵ is very big, the ECO behaves more like a star than a black hole. On the contrary, if ϵ tends to a very small value, the ECO behaves like a black hole. It is considered a conceptual model of the origin of the cutoff for ECOs, when a dust shell contracts gravitationally from an initial position to near the Schwarzschild radius. This allowed us to find that the cutoff makes two types of contributions: a classical one governed by General Relativity and one of a quantum nature, if the ECO is very close to the horizon, when estimating that the maximum entropy is contained within the material that composes the shell. Such entropy coincides with the Bekenstein–Hawking entropy. The established cutoff corresponds to a dynamic quantity dependent on coordinate time that is measured by a Fiducial Observer (FIDO). Without knowing the details about quantum gravity, parameter ϵ is calculated, which, in general, allows distinguishing the ECOs from BHs. Specifically, a black shell (ECO) is undistinguishable from a BH.
Chironomus riparius Proteome Responses to Spinosad Exposure
Authors: Monteiro Hugo R. , Pestana João L. T. , Soares Amadeu M. V. M. , Devreese Bart , Lemos Marco F. L.
Published: December 2020

The potential of proteome responses as early-warning indicators of insecticide exposure was evaluated using the non-biting midge Chironomus riparius (Meigen) as the model organism. Chironomus riparius larvae were exposed to environmentally relevant concentrations of the neurotoxic pesticide spinosad to uncover molecular events that may provide insights on the long-term individual and population level consequences. The iTRAQ labeling method was performed to quantify protein abundance changes between exposed and non-exposed organisms. Data analysis revealed a general dose-dependent decrease in the abundance of globin proteins as a result of spinosad exposure. Additionally, the downregulation of actin and a larval cuticle protein was also observed after spinosad exposure, which may be related to previously determined C. riparius life-history traits impairment and biochemical responses. Present results suggest that protein profile changes can be used as early warning biomarkers of pesticide exposure and may provide a better mechanistic interpretation of the toxic response of organisms, aiding in the assessment of the ecological effects of environmental contamination. This work also contributes to the understanding of the sublethal effects of insecticides in invertebrates and their molecular targets.
Exposure to Aerosolized Algal Toxins in South Florida Increases Short- and Long-Term Health Risk in Drosophila Model of Aging
Authors: Hu Jiaming , Liu Jiaqi , Zhu Yi , Diaz-Perez Zoraida , Sheridan Michael , Royer Haley , Leibensperger Raymond , Maizel Daniela , Brand Larry , Popendorf Kimberly J. , Gaston Cassandra J. , Zhai R. Grace
Published: December 2020

Harmful algal blooms (HABs) are a rising health and environmental concern in the United States, particularly in South Florida. Skin contact and the ingestion of contaminated water or fish and other seafood have been proven to have severe toxicity to humans in some cases. However, the impact of aerosolized HAB toxins is poorly understood. In particular, knowledge regarding either the immediate or long-term effects of exposure to aerosolized cyanotoxins produced by freshwater blue-green algae does not exist. The aim of this study was to probe the toxicity of aerosolized cyanobacterial blooms using Drosophila melanogaster as an animal model. The exposure of aerosolized HABs at an early age leads to the most severe long-term impact on health and longevity among all age groups. Young groups and old males showed a strong acute response to HAB exposure. In addition, brain morphological analysis using fluorescence imaging reveals significant indications of brain degeneration in females exposed to aerosolized HABs in early or late stages. These results indicate that one-time exposure to aerosolized HAB particles causes a significant health risk, both immediately and in the long-term. Interestingly, age at the time of exposure plays an important role in the specific nature of the impact of aerosol HABs. As BMAA and microcystin have been found to be the significant toxins in cyanobacteria, the concentration of both toxins in the water and aerosols was examined. BMAA and microcystin are consistently detected in HAB waters, although their concentrations do not always correlate with the severity of the health impact, suggesting the potential contribution from additional toxins present in the aerosolized HAB. This study demonstrates, for the first time, the health risk of exposure to aerosolized HAB, and further highlights the critical need and importance of understanding the toxicity of aerosolized cyanobacteria HAB particles and determining the immediate and long-term health impacts of HAB exposure.
A Review on Mycotoxins and Microfungi in Spices in the Light of the Last Five Years
Authors: Pickova Darina , Ostry Vladimir , Malir Jan , Toman Jakub , Malir Frantisek
Published: December 2020

Spices are imported worldwide mainly from developing countries with tropical and/or subtropical climate. Local conditions, such as high temperature, heavy rainfall, and humidity, promote fungal growth leading to increased occurrence of mycotoxins in spices. Moreover, the lack of good agricultural practice (GAP), good manufacturing practice (GMP), and good hygienic practice (GHP) in developing countries are of great concern. This review summarizes recent data from a total of 56 original papers dealing with mycotoxins and microfungi in various spices in the last five years. A total of 38 kinds of spices, 17 mycotoxins, and 14 microfungi are discussed in the review. Worldwide, spices are rather overlooked in terms of mycotoxin regulations, which usually only cover aflatoxins (AFs) and ochratoxin A (OTA). In this paper, an extensive attention is devoted to the limits on mycotoxins in spices in the context of the European Union (EU) as well as other countries. As proven in this review, the incidence of AFs and OTA, as well as other mycotoxins, is relatively high in many spices; thus, the preparation of new regulation limits is advisable.
Prevention of Periprosthetic Joint Infection (PJI): A Clinical Practice Protocol in High-Risk Patients
Authors: Iannotti Ferdinando , Prati Paolo , Fidanza Andrea , Iorio Raffaele , Ferretti Andrea , Pèrez Prieto Daniel , Kort Nanne , Violante Bruno , Pipino Gennaro , Schiavone Panni Alfredo , Hirschmann Michael , Mugnaini Marco , Indelli Pier Francesco
Published: December 2020

Background: Periprosthetic joint infection (PJI) represents 25% of failed total knee arthroplasties (TKA). The European Knee Associates (EKA) formed a transatlantic panel of experts to perform a literature review examining patient-related risk factors with the objective of producing perioperative recommendations in PJI high-risk patients. Methods: Multiple databases (Pubmed/MEDLINE, EMBASE, Scopus, Cochrane Library) and recommendations on TKA PJI prevention measures from the International Consensus Meetings on PJI from the AAOS and AAHKS were reviewed. This represents a Level IV study. Results: Strong evidence was found on poor glycemic control, obesity, malnutrition, and smoking being all associated with increased rates of PJI. In the preoperative period, patient optimization is key: BMI < 35, diet optimization, Hemoglobin A1c < 7.5, Fructosamine < 292 mmol/L, smoking cessation, and MRSA nasal screening all showed strong evidence on reducing PJI risk. Intraoperatively, a weight-based antibiotic prophylaxis, accurate fluid resuscitation, betadine and chlorhexidine dual skin preparation, diluted povidone iodine solution irrigation, tranexamic acid administration, and monofilament barbed triclosan-coated sutures for soft tissues closure all represented effective prevention measures. In the postoperative period, failure to reach normalization of ESR, CRP, D-dimer, and IL-6 six weeks postoperatively suggested early PJI. Conclusion: The current recommendations from this group of experts, based on published evidence, support risk stratification to identify high-risk patients requiring implementation of perioperative measures to reduce postoperative PJI.
Towards Creating a Global Urban Toponymy—A Comment
Authors: Bigon Liora
Published: December 2020

This commentary points to the problems inherent in critical place names studies in terms of classic research topics, methodologies and geographies. It expounds the limits of the official “index”, that is, the variety of traditional urban inscriptions on which critical toponymy scholars rely in interpreting modern urban spatialities—e.g., lists of street names, official street signage, gazetteers, archival materials, etc. The argument is that in Southern urban contexts, where informality in planning can reach up to about 80 percent of the city, researching official naming and signage renders a distorted image of the city and its namescape production. A comment is thus made on the need to embrace more innovative and almost ethnographic research methodologies for understanding place referencing, place attachment and everyday navigational channels in Southern cities. These will generate a more substantial contribution towards the creation of global urban toponymy and a further de-colonization of Eurocentric presumptions regarding governmentality, urban management, and the accompanying role of street naming systems.
Identification of the Cleavage Domain within Glycoprotein G of Herpes Simplex Virus Type 2
Authors: Kropp Kai A. , Srivaratharajan Sangar , Ritter Birgit , Yu Pengfei , Krooss Simon , Polten Felix , Pich Andreas , Alcami Antonio , Viejo-Borbolla Abel
Published: December 2020

Glycoprotein G (gG) from herpes simplex virus type 1 and 2 (HSV-1 and HSV-2, respectively) functions as a viral chemokine binding protein (vCKBP). Soluble recombinant forms of gG of HSV-1 and HSV-2 (SgG1 and SgG2, respectively) enhance chemokine-mediated leukocyte migration, in contrast to most known vCKBPs, including those from animal alpha-herpesviruses. Furthermore, both proteins bind to nerve growth factor (NGF), but only SgG2 enhances NGF-dependent neurite outgrowth. The basis and implications of this functional difference between the two proteins are still unknown. While gG1 and gG2 are positional homologues in the genome, they share very limited sequence homology. In fact, US4, the open reading frame encoding gG is the most divergent genetic locus between these viruses. Full-length gG1 and gG2 are type I transmembrane proteins located on the plasma membrane of infected cells and at the viral envelope. However, gG2 is larger than gG1 and is cleaved during protein maturation, secreting the N-terminal domain to the supernatant of infected cells, whereas gG1 is not. The enzyme involved in gG2 cleavage and the functional relevance of gG2 cleavage and secretion are unknown. We aim to identify the gG2 sequence required for cleavage to determine its functional role in future experiments. Our results prove the existence of at least two cleavage motifs in gG2 within the amino acid region 314-343. Transfer of this sequence to a fusion protein results in cleavage. Finally, we show that propeptide convertases like furin are responsible for gG2 cleavage.