bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in Consumption in the Early COVID-19 Era: Zip-Code Level Evidence from the U.S.
Authors: Yilmazkuday Hakan
Published: October 2021

Using monthly zip-code level data on credit card transactions covering 16 U.S. cities, this paper investigates changes in consumption at local commercial places during the early coronavirus disease 2019 (COVID-19) era. Since using aggregate-level data can suppress valuable information on consumption patterns coming from zip codes, the main contribution is achieved by estimating common factors across zip codes that are controlled for factors that are zip-code and time specific as well as those that are zip-code and sector specific. The estimation results based on common factors across zip codes show that relative consumption of products and services that can be consumed at home (e.g., grocery, pharmacy, home maintenance) has increased up to 56% amid COVID-19 compared to the previous year, whereas relative consumption of products and services that cannot be consumed at home (e.g., fuel, transportation, personal care services, restaurant) has decreased up to 51%. Similarly, after controlling for the corresponding factors, online shopping has increased up to 21%, while its expenditure share has increased by up to 16% compared to the pre-COVID-19 period.
Does Fixed Income Buffer against Fraud Shocks?
Authors: Lee Steven James
Published: October 2021

Counterparty risk in the form of investment fraud damages a retiree’s nest egg. Does fraud negatively impact portfolios that are both stock and bond-heavy equally? This study uses Monte Carlo analysis within the Trinity Study framework to determine the average reduction in portfolio success of a retiree who experiences fraud. Findings suggest that each incidence of fraud results in a loss of three percentage points in retirement success. However, portfolios containing some bonds (75/25, 50/50, and 25/75) outperform all equity (and all bond) allocations, particularly when fraud is present. On average, each incident of fraud reduces the chance the victim will enjoy a successful retirement by nearly 3%. Various limitations, implications, and future research possibilities are discussed.
Spatial and Temporal Changes of Ecosystem Service Value in Airport Economic Zones in China
Authors: Niu Yingnan , Xie Gaodi , Xiao Yu , Qin Keyu , Gan Shuang , Liu Jingya
Published: October 2021

With the rapid development of the aviation industry, many negative effects on the local environment have been reported. This study examined the land use and land cover (LULC) and ecosystem service value (ESV) of airport economic zones (AEZs) in China and assessed the changes in LULC and ESV. The results indicate that LULC changed significantly from 1990 to 2015, characterized by the increase in construction land (increase rate, 68.53%) and water bodies (increase rate, 2.32%) and the decrease in cropland (decrease rate, 4.28%), forest (decrease rate, 0.73%), grassland (decrease rate, 4.64%) and unused land (decrease rate, 6.36%). The ESV of AEZs in 1990 and 2015 was RMB 3454 and 3483 million, respectively, with an overall ESV change of RMB 29 million. The ESV of AEZs is characterized by high value in the coastal area of China. From 1990 to 2015, AEZs with a high ESV were located in Inner Mongolia, while those with a high decrease in ESV were located in the southeastern coastal area. From 1990 to 2000, the AEZs with a high increase in ESV were located in Inner Mongolia and Qinghai and the AEZs with decreased ESV were mostly located in central and south China. However, from 2000 to 2010, AEZs with high and low increases in ESV were located in central China and the south coastal area of China, respectively. From 2010 to 2015, AEZs with a high decrease in ESV were located in southeast China.
Application of the Adapted Approach for Crop Management Factor to Assess Soil Erosion Risk in an Agricultural Area of Rwanda
Authors: Maniraho Albert Poponi , Mind’je Richard , Liu Wenjiang , Nzabarinda Vincent , Kayumba Patient Mindje , Nahayo Lamek , Umugwaneza Adeline , Uwamahoro Solange , Li Lanhai
Published: October 2021

Land use and land cover (LULC) management influences the severity of soil erosion risk. However, crop management (C) is one factor of the Revised Universal Soil Loss Equation (RUSLE) model that should be taken into account in its determination, as it influences soil loss rate estimations. Thus, the present study applied an adapted C-factor estimation approach (CvkA) modified from the former approach (Cvk) to assess the impact of LULC dynamics on soil erosion risk in an agricultural area of Rwanda taking the western province as a case study. The results disclosed that the formerly used Cvk was not suitable, as it tended to overestimate C-factor values compared with the values obtained from t CvkA. An approximated mean soil loss of 15.1 t ha−1 yr−1, 47.4 t ha−1 yr−1, 16.3 t ha−1 yr−1, 66.8 t ha−1 yr−1 and 15.3 t ha−1 yr−1 in 2000, 2005, 2010, 2015 and 2018, respectively, was found. The results also indicated that there was a small increase in mean annual soil loss from 15.1 t ha−1 yr−1 in 2000 to 15.3 t ha−1 yr−1 in 2018 (1.3%). Moreover, the soil erosion risk categories indicated that about 57.5%, 21.8%, 64.9%, 15.5% and 73.8% had a sustainable soil erosion rate tolerance (≤10 t ha−1 yr−1), while about 42.5%, 78.2%, 35.1%, 84.5% and 16.8% had an unsustainable mean soil erosion rate (>10 t ha−1 yr−1) in 2000, 2005, 2010, 2015 and 2018, respectively. A major portion of the area fell under the high and very high probability zones, whereas only a small portion fell under the very low, low, moderate and extremely high probability zones. Therefore, the CvkA approach presents the most suitable alternative to estimate soil loss in the western province of Rwanda with reasonable soil loss prediction results. The study area needs urgent intervention for soil conservation planning, taking into account the implementation of effective conservation practices such as terracing for soil erosion control.
Attribution Analysis of Runoff Variation in Kuye River Basin Based on Three Budyko Methods
Authors: Zheng Jiahao , He Yi , Jiang Xiaohui , Nie Tong , Lei Yuxin
Published: October 2021

The Loess Plateau is the main soil erosion area within the Yellow River Basin. Quantifying the contribution rate of climate change and human activities to runoff change can provide support for water resources management in the Yellow River Basin. Kuye River Basin is located in the Loess Plateau. As a first-class tributary of the Yellow River, it was selected as the study area. Runoff from the Kuye River Basin has decreased significantly since the 1990s owing to climate change and anthropogenic coal mining. The main objective of this study was to quantify the contribution and sensitivity of climate change and anthropogenic activities to runoff changes using three popular Budyko and elasticity coefficient methods, as well as to compare the similarities and differences among the three methods. The results show that: (1) Through four mutation point test methods, the change point of runoff in the study period of Kuye River Basin is 1997. (2) The elasticity coefficients calculated by the three Budyko methods showed that during the study period, the runoff was more sensitive to changes in precipitation, followed by the catchment surface characteristic parameters and the potential evapotranspiration. (3) All three Budyko methods can yield reasonable contributions of climate change and human activity to runoff changes. The three methods together indicate that the influence of the catchment surface characteristic parameters is the most important factor for the runoff variation in the Kuye River.
Land Grabbing and Jatropha in India: An Analysis of ‘Hyped’ Discourse on the Subject
Authors: Trebbin Anika
Published: October 2021

In the early 2000s, powerful narratives (re-)emerged around the food–fuel–land nexus, which, combined with the financial, food, and fuel crises of 2007–08, sparked new concerns about the finiteness of our resources and triggered, as well as partially justified, the then following land rush. Around the same time, a hyped debate also developed around biofuels as a potential fix to some of the global scarcity problems in which jatropha held a particularly prominent position as a new miracle crop. This study examines the concurrence of jatropha and the land grabbing hype in India, the leading promotor of the plant globally, and asks what effect the global land grab discourse had on actual jatropha investments in the country. To do so, an extensive literature review, discourse analysis, and qualitative survey were conducted, with a specific focus on jatropha investors. The study found that both hyped discourses have impacted investor decisions, but the impact varied depending on the types of company. This study adds a yet underrepresented investor perspective to the global land grabbing discourse and highlights a need to also consider the role of small and medium enterprises in land grabbing processes.
Spatial Grain Effects of Urban Green Space Cover Maps on Assessing Habitat Fragmentation and Connectivity
Authors: Lin Yue , An Wenzhan , Gan Muye , Shahtahmassebi AmirReza , Ye Ziran , Huang Lingyan , Zhu Congmou , Huang Lu , Zhang Jing , Wang Ke
Published: October 2021

The scientific evaluation of landscape fragmentation and connectivity is important for habitat conservation. It is strongly influenced by the spatial resolution of source maps, particularly in urban environments. However, there is limited comprehensive investigation of the spatial grain effect on urban habitat and few in-depth analysis across different urban gradients. In this paper, we scrutinize the spatial grain effects of urban green space (UGS) cover maps (derived from remote sensing imagery and survey data) with respect to evaluating habitat fragmentation and connectivity, comparing among different urban gradient scenarios (downtown, urban periphery, and suburban area) in Hangzhou, a megacity in China. The fragmentation was detected from three indices, including Entropy, Contagion, and Hypsometry. Then morphological spatial pattern analysis (MSPA) was applied for the landscape element identification. The possibility of connectivity (PC) and patch importance (dPC) were proposed for measuring the landscape connectivity based on Cores and Bridges from MSPA results. The results indicate that the farther the location is from downtown, the less sensitive the landscape element proportion to the spatial resolution. Among the three fragmentation indices, the overall hypsometry index has the lowest sensitivity to the spatial resolution, which implies this index’s broader application value. Considering connectivity, high spatial resolution maps are appropriate for analyzing highly heterogeneous urban areas, while medium spatial resolution maps are more applicable to urban periphery and suburban area with larger UGS patches and less fragmentation. This study suggests that the spatial resolution of UGS maps substantially influence habitat fragmentation and connectivity, which is critical for decision making in urban planning and management.
Anthropogenic and Climatic Factors Differentially Affect Waterbody Area and Connectivity in an Urbanizing Landscape: A Case Study in Zhengzhou, China
Authors: Liu Chang , Minor Emily S. , Garfinkel Megan B. , Mu Bo , Tian Guohang
Published: October 2021

Urbanization alters the distribution and characteristics of waterbodies, potentially affecting both the habitat availability and connectivity for aquatic wildlife. We used Landsat satellite imagery to observe temporal and spatial changes in open-water habitats in Zhengzhou, a rapidly growing city in central China. We classified open water into six categories: perennial rivers, seasonal rivers and streams, canals, lakes, ponds, and reservoirs. From 1990 to 2020, in 5-year intervals, we identified, counted, and measured the area of each kind of waterbody, and we used a model selection approach with linear regressions to ask which climate and anthropogenic drivers were associated with these changes. We also used Conefor software to examine how these changes affected the landscape connectivity for waterfowl. Over the study period, lakes and canals were the only waterbody types to show statistically significant changes in surface area, increasing by 712% and 236%, respectively. Changes in lakes and canals were positively correlated with the length of water pipeline in the city. The connectivity of waterbodies fluctuated over the same period, mirroring fluctuations in the perennial Yellow River. Ponds contributed very little to landscape connectivity, and the importance of reservoirs decreased over time. Conversely, canals played an increasingly important role in landscape connectivity over time. Counterintuitively, the connectivity of waterbodies increased in the built-up part of the city. Our results show that urbanization can have unexpected effects—both positive and negative—on the connectivity and area of open-water habitats. These effects are likely to be important for waterfowl and other aquatic organisms.
The Structure, Activity, and Function of the SETD3 Protein Histidine Methyltransferase
Authors: Witecka Apolonia , Kwiatkowski Sebastian , Ishikawa Takao , Drozak Jakub
Published: October 2021

SETD3 has been recently identified as a long sought, actin specific histidine methyltransferase that catalyzes the Nτ-methylation reaction of histidine 73 (H73) residue in human actin or its equivalent in other metazoans. Its homologs are widespread among multicellular eukaryotes and expressed in most mammalian tissues. SETD3 consists of a catalytic SET domain responsible for transferring the methyl group from S-adenosyl-L-methionine (AdoMet) to a protein substrate and a RuBisCO LSMT domain that recognizes and binds the methyl-accepting protein(s). The enzyme was initially identified as a methyltransferase that catalyzes the modification of histone H3 at K4 and K36 residues, but later studies revealed that the only bona fide substrate of SETD3 is H73, in the actin protein. The methylation of actin at H73 contributes to maintaining cytoskeleton integrity, which remains the only well characterized biological effect of SETD3. However, the discovery of numerous novel methyltransferase interactors suggests that SETD3 may regulate various biological processes, including cell cycle and apoptosis, carcinogenesis, response to hypoxic conditions, and enterovirus pathogenesis. This review summarizes the current advances in research on the SETD3 protein, its biological importance, and role in various diseases.
Characterization of an Aerosol-Based Photobioreactor for Cultivation of Phototrophic Biofilms
Authors: Strieth Dorina , Weber Andreas , Robert Johannes , Stiefelmaier Judith , Kollmen Jonas , Volkmar Marianne , Lakatos Michael , Jordan Volkmar , Muffler Kai , Ulber Roland
Published: October 2021

Phototrophic biofilms, in particular terrestrial cyanobacteria, offer a variety of biotechnologically interesting products such as natural dyes, antibiotics or dietary supplements. However, phototrophic biofilms are difficult to cultivate in submerged bioreactors. A new generation of biofilm photobioreactors imitates the natural habitat resulting in higher productivity. In this work, an aerosol-based photobioreactor is presented that was characterized for the cultivation of phototrophic biofilms. Experiments and simulation of aerosol distribution showed a uniform aerosol supply to biofilms. Compared to previous prototypes, the growth of the terrestrial cyanobacterium Nostoc sp. could be almost tripled. Different surfaces for biofilm growth were investigated regarding hydrophobicity, contact angle, light- and temperature distribution. Further, the results were successfully simulated. Finally, the growth of Nostoc sp. was investigated on different surfaces and the biofilm thickness was measured noninvasively using optical coherence tomography. It could be shown that the cultivation surface had no influence on biomass production, but did affect biofilm thickness.
Sorafenib Combined with Chemoembolization for Locally Advanced Hepatocellular Carcinoma with Macroscopic Vascular Invasion: A Propensity Score Analysis
Authors: Kim Gun Ha , Choi Sang Lim , Kim Jin Hyoung , Shim Ju Hyun , Alali Meshari , Kim Nayoung
Published: October 2021

The purpose of this study was to compare the efficacy and safety of transarterial chemoembolization (TACE) plus sorafenib with those of TACE alone in patients with locally advanced hepatocellular carcinoma (HCC). Treatment-naïve patients with preserved hepatic reserve (Child–Pugh score ≤ 7) who received TACE plus sorafenib (n = 91) or TACE alone (n = 109) for locally advanced HCC with macrovascular invasion were retrospectively evaluated. Propensity score matching (PSM) was used to correct selection bias, and 63 pairs were created. In the entire study population, the median progression-free survival (PFS) and overall survival (OS) with TACE plus sorafenib were better than those with TACE alone. After PSM, the median PFS (7.0 vs. 4.3 months; p = 0.017) and OS (17.5 vs. 12.8 months; p = 0.049) were again significantly longer with TACE plus sorafenib than with TACE alone. Stratified Cox regression analysis and doubly robust estimation revealed that treatment type was significantly associated with both PFS and OS. In the subgroup analysis, TACE plus sorafenib did not show a significant survival benefit for patients with main portal vein or inferior vena cava invasion. Major complications were similar in both groups (p = 0.330). In conclusion, TACE plus sorafenib showed better survival outcomes than TACE alone in patients with locally advanced HCC.
Cutaneous Localization of Classic Hodgkin Lymphoma Associated with Mycosis Fungoides: Report of a Rare Event and Review of the Literature
Authors: Zanelli Magda , Ricci Stefano , Sanguedolce Francesca , Palicelli Andrea , Farnetti Enrico , Tafuni Alessandro , Zizzo Maurizio , Valli Riccardo , Celis Maria Isabel Alvarez De , Cavazza Alberto , Longo Caterina , Ascani Stefano
Published: October 2021

Mycosis fungoides and nodal classic Hodgkin lymphoma (cHL) have been reported to occur concurrently or sequentially in the same patient. A long-lasting mycosis fungoides more often precedes the onset of nodal cHL, although few cases of nodal cHL followed by mycosis fungoides have been observed. Skin involvement is a rare manifestation of cHL that may be observed in the setting of advanced disease. The decrease in skin involvement in cHL is mainly due to the improved therapeutic strategies. The concurrent presence of mycosis fungoides and cutaneous localization of classic Hodgkin lymphoma represents a very uncommon event, with only two cases reported so far. Herein, we describe the case of a 71-year-old man, with a history of recurrent nodal cHL, who developed MF and, subsequently, the cutaneous localization of cHL. The clinicopathological features of the two diseases are described focusing on the main differential diagnoses to be taken into consideration, and a review of the literature is performed.
Modelling of Frictional Conditions in the Wheel–Rail Interface Due to Application of Top-of-Rail Products
Authors: Trummer Gerald , Lee Zing Siang , Lewis Roger , Six Klaus
Published: October 2021

The coefficient of friction between a wheel tread and the top of the rail should be maintained at intermediate levels to limit frictional tangential contact forces. This can be achieved by applying top-of-rail products. Reducing the coefficient of friction to intermediate levels reduces energy consumption and fuel costs, as well as damage to the wheel and rail surfaces, such as, e.g., wear, rolling contact fatigue, and corrugation. This work describes a simulation model that predicts the evolution of the coefficient of friction as a function of the number of wheel passes and the distance from the application site for wayside application of top-of-rail products. The model considers the interplay of three mechanisms, namely the pick-up of product by the wheel at the application site, the repeated transfer of the product between the wheel and rail surfaces, and the product consumption. The model has been parameterized with data from small-scale twin disc rig experiments and full-scale wheel–rail rig experiments. Systematic investigations of the model behaviour for a railway operating scenario show that all three mechanisms may limit the achievable carry-on distance of the product. The developed simulation model assists in understanding the interplay of the mechanisms that govern the evolution of the coefficient of friction in the field. It may aid in finding optimal product application strategies with respect to application position, application amount, and application pattern depending on specific railway operating conditions.
Design Rules for Hybrid Additive Manufacturing Combining Selective Laser Melting and Micromilling
Authors: Sommer David , Götzendorfer Babette , Esen Cemal , Hellmann Ralf
Published: October 2021

We report on a comprehensive study to evaluate fundamental properties of a hybrid manufacturing approach, combining selective laser melting and high speed milling, and to characterize typical geometrical features and conclude on a catalogue of design rules. As for any additive manufacturing approach, the understanding of the machine properties and the process behaviour as well as such a selection guide is of upmost importance to foster the implementation of new machining concepts and support design engineers. Geometrical accuracy between digitally designed and physically realized parts made of maraging steel and dimensional limits are analyzed by stripe line projection. In particular, we identify design rules for numerous basic geometric elements like walls, cylinders, angles, inclinations, overhangs, notches, inner and outer radii of spheres, chamfers in build direction, and holes of different shape, respectively, as being manufactured by the hybrid approach and compare them to sole selective laser melting. While the cutting tool defines the manufacturability of, e.g., edges and corners, the milling itself improves the surface roughness to Ra < 2μm. Thus, the given advantages of this hybrid process, e.g., space-resolved and custom-designed roughness and the superior geometrical accuracy are evaluated. Finally, we exemplify the potential of this particular promising hybrid approach by demonstrating an injection mold with a conformal cooling for a charge socket for an electro mobile.
Numerical Optimization for the Impact Performance of a Rubber Ring Buffer of a Train Coupler
Authors: Xu Ping , Qu Chengju , Yao Shuguang , Yang Chengxing , Wang Ao
Published: October 2021

Shock and vibration caused by mechanical motion bring huge potential threats to the service life and assembly reliability of mechanical systems. Rubber materials have been widely used in aircraft, trains, and other engineering fields, due to their excellent properties in shock and vibration absorption. This paper aimed to study the rubber ring buffer applied to a certain type of Chinese locomotive. Firstly, the finite element model was established and verified through experimental data. Based on the verified simulation model, the influence of the constitutive parameters (C01/C10 ratio height H and contour radius R) of the rubber ring on its energy absorption and peak crushing force under impact loading was studied in a numerical environment. Finally, the design of the experiment was carried out by the optimized Latin hypercube method, and the response surface model was established, which intuitively demonstrated the influence of the relevant parameters of the rubber ring on the change trend of the energy absorption and peak force. Based on the proxy model, the parameters that improve the crashworthiness of the rubber ring buffer were found quickly by the NSGA-II optimization algorithm, and the problems of a long calculation time and low optimization efficiency when using the conventional finite element method were avoided. The optimization results stated that when H = 107.57 mm and R = 85.70 mm, C01/C10 = 0.0571 of the energy absorption of the optimized buffer was increased by 59.03%, and the peak force was decreased by 14.37%, compared with the original structure. The optimized rubber ring buffer is expected to reduce the peak crushing force, enhance the energy absorption capacity, and mitigate the damage to the train system caused by shock and vibration.
A 3D Keypoints Voting Network for 6DoF Pose Estimation in Indoor Scene
Authors: Liu Huikai , Liu Gaorui , Zhang Yue , Lei Linjian , Xie Hui , Li Yan , Sun Shengli
Published: October 2021

This paper addresses the problem of instance-level 6DoF pose estimation from a single RGBD image in an indoor scene. Many recent works have shown that a two-stage network, which first detects the keypoints and then regresses the keypoints for 6d pose estimation, achieves remarkable performance. However, the previous methods concern little about channel-wise attention and the keypoints are not selected by comprehensive use of RGBD information, which limits the performance of the network. To enhance RGB feature representation ability, a modular Split-Attention block that enables attention across feature-map groups is proposed. In addition, by combining the Oriented FAST and Rotated BRIEF (ORB) keypoints and the Farthest Point Sample (FPS) algorithm, a simple but effective keypoint selection method named ORB-FPS is presented to avoid the keypoints appear on the non-salient regions. The proposed algorithm is tested on the Linemod and the YCB-Video dataset, the experimental results demonstrate that our method outperforms the current approaches, achieves ADD(S) accuracy of 94.5% on the Linemod dataset and 91.4% on the YCB-Video dataset.
A Digital Twin-Oriented Lightweight Approach for 3D Assemblies
Authors: Fang Luo , Liu Qiang , Zhang Ding
Published: October 2021

In the design and operation scenarios driven by Digital Twins, large computer-aided design (CAD) models of production line equipment can limit the real-time performance and fidelity of the interaction between digital and physical entities. Digital CAD models often consist of combined parts with characteristics of discrete folded corner planes. CAD models simplified to a lower resolution by current mainstream mesh simplification algorithms might suffer from significant feature loss and mesh breakage, and the interfaces between the different parts cannot be well identified and simplified. A lightweight approach for common CAD assembly models of Digital Twins is proposed. Based on quadric error metrics, constraints of discrete folded corner plane characteristics of Digital Twin CAD models are added. The triangular regularity in the neighborhood of the contraction target vertices is used as the penalty function, and edge contraction is performed based on the cost. Finally, a segmentation algorithm is employed to identify and remove the interfaces between the two CAD assembly models. The proposed approach is verified through common stereoscopic warehouse, robot base, and shelf models. In addition, a scenario of a smart phone production line is applied. The experimental results indicate that the geometric error of the simplified mesh is reduced, the frame rate is improved, and the integrity of the geometric features and triangular facets is effectively preserved.
Magnetic Field Perturbations to a Soft X-ray-Activated Fe (II) Molecular Spin State Transition
Authors: Hao Guanhua , N’Diaye Alpha T. , Ekanayaka Thilini K. , Dale Ashley S. , Jiang Xuanyuan , Mishra Esha , Mellinger Corbyn , Yazdani Saeed , Freeland John W. , Zhang Jian , Cheng Ruihua , Xu Xiaoshan , Dowben Peter A.
Published: October 2021

The X-ray-induced spin crossover transition of an Fe (II) molecular thin film in the presence and absence of a magnetic field has been investigated. The thermal activation energy barrier in the soft X-ray activation of the spin crossover transition for [Fe{H2B(pz)2}2(bipy)] molecular thin films is reduced in the presence of an applied magnetic field, as measured through X-ray absorption spectroscopy at various temperatures. The influence of a 1.8 T magnetic field is sufficient to cause deviations from the expected exponential spin state transition behavior which is measured in the field free case. We find that orbital moment diminishes with increasing temperature, relative to the spin moment in the vicinity of room temperature.
A Quantum-Mechanical Study of Antiphase Boundaries in Ferromagnetic B2-Phase Fe2CoAl Alloy
Authors: Friák Martin , Gracias Josef , Pavlů Jana , Šob Mojmír
Published: October 2021

In this study, we performed a quantum mechanical examination of thermodynamic, structural, elastic, and magnetic properties of single-phase ferromagnetic Fe2CoAl with a chemically disordered B2-type lattice with and without antiphase boundaries (APBs) with (001) crystallographic orientation. Fe2CoAl was modeled using two different 54-atom supercells with atoms on the two B2 sublattices distributed according to the special quasi-random structure (SQS) concept. Both computational models exhibited very similar formation energies (−0.243 and −0.244 eV/atom), B2 structure lattice parameters (2.849 and 2.850 Å), magnetic moments (1.266 and 1.274 μB/atom), practically identical single-crystal elastic constants (C11 = 245 GPa, C12 = 141 GPa, and similar C44 = 132 GPa) and auxetic properties (the lowest Poisson ratio close to −0.1). The averaged APB interface energies were observed to be 199 and 310 mJ/m2 for the two models. The studied APBs increased the total magnetic moment by 6 and 8% due to a volumetric increase as well as local changes in the coordination of Fe atoms (their magnetic moments are reduced for increasing number of Al neighbors but increased by the presence of Co). The APBs also enhanced the auxetic properties.
The Underexplored Field of Lanthanide Complexes with Helicene Ligands: Towards Chiral Lanthanide Single Molecule Magnets
Authors: Handzlik Gabriela , Rzepka Katarzyna , Pinkowicz Dawid
Published: October 2021

The effective combination of chirality and magnetism in a single crystalline material can lead to fascinating cross-effects, such as magneto-chiral dichroism. Among a large variety of chiral ligands utilized in the design and synthesis of chiral magnetic materials, helicenes seem to be the most appealing ones, due to the exceptionally high specific rotation values that reach thousands of deg·cm3·g−1·dm−1, which is two orders of magnitude higher than for compounds with chiral carbon atoms. Despite the sizeable family of transition metal complexes with helicene-type ligands, there are only a few examples of such complexes with lanthanide ions. In this mini-review, we describe the most recent developments in the field of lanthanide-based complexes with helicene-type ligands and summarize insights regarding the further exploration of this family of compounds towards multifunctional chiral lanthanide single molecule magnets (Ln-SMMs).
Mathematical Modeling of Immune Responses against SARS-CoV-2 Using an Ensemble Kalman Filter
Authors: Ghostine Rabih , Gharamti Mohamad , Hassrouny Sally , Hoteit Ibrahim
Published: October 2021

In this paper, a mathematical model was developed to simulate SARS-CoV-2 dynamics in infected patients. The model considers both the innate and adaptive immune responses and consists of healthy cells, infected cells, viral load, cytokines, natural killer cells, cytotoxic T-lymphocytes, B-lymphocytes, plasma cells, and antibody levels. First, a mathematical analysis was performed to discuss the model’s equilibrium points and compute the basic reproduction number. The accuracy of such mathematical models may be affected by many sources of uncertainties due to the incomplete representation of the biological process and poorly known parameters. This may strongly limit their performance and prediction skills. A state-of-the-art data assimilation technique, the ensemble Kalman filter (EnKF), was then used to enhance the model’s behavior by incorporating available data to determine the best possible estimate of the model’s state and parameters. The proposed assimilation system was applied on the real viral load datasets of six COVID-19 patients. The results demonstrate the efficiency of the proposed assimilation system in improving the model predictions by up to 40%.
Practices of the Random Variable Proposed in the Chilean Mathematics Curriculum of Secondary Education
Authors: Carrera Patricia Belén , Pino-Fan Luis R. , Alvarado Hugo , Lugo-Armenta Jesús Guadalupe
Published: October 2021

Working with statistical data from real contexts has become fundamental in school-level statistics, because it enables the development of statistical reasoning. In this regard, the notion of the random variable is fundamental to statistical data analysis. Thus, the aim of this research was to characterise the meanings of the concept of the random variable that are promoted in the Chilean mathematics curriculum for secondary education. To achieve this, we examined the representativeness of the meanings of the random variable intended by the curriculum in relation to the meanings of reference for this concept, using theoretical and methodological notions from the onto-semiotic approach. The findings show that the meanings of reference were not fully represented in the textbooks and the national curriculum, and that the most promoted meaning was that of the random variable as a variable of interest. Regarding the types of representation, it was observed that the graphical and tabular representations were neglected. Lastly, it was noticed that definitions of the concept of variable, its classifications, and differences were omitted almost entirely from the textbooks.
Learning Impulsive Pinning Control of Complex Networks
Authors: Alanis Alma Y. , Ríos-Rivera Daniel , Sanchez Edgar N. , Sanchez Oscar D.
Published: October 2021

In this paper, we present an impulsive pinning control algorithm for discrete-time complex networks with different node dynamics, using a linear algebra approach and a neural network as an identifier, to synthesize a learning control law. The model of the complex network used in the analysis has unknown node self-dynamics, linear connections between nodes, where the impulsive dynamics add feedback control input only to the pinned nodes. The proposed controller consists of the linearization for the node dynamics and a reorder of the resulting quadratic Lyapunov function using the Rayleigh quotient. The learning part of the control is done with a discrete-time recurrent high order neural network used for identification of the pinned nodes, which is trained using an extended Kalman filter algorithm. A numerical simulation is included in order to illustrate the behavior of the system under the developed controller. For this simulation, a 20-node complex network with 5 different node dynamics is used. The node dynamics consists of discretized versions of well-known continuous chaotic attractors.
Shadowed Type-2 Fuzzy Systems for Dynamic Parameter Adaptation in Harmony Search and Differential Evolution for Optimal Design of Fuzzy Controllers
Authors: Castillo Oscar , Peraza Cinthia , Ochoa Patricia , Amador-Angulo Leticia , Melin Patricia , Park Yongjin , Geem Zong Woo
Published: October 2021

This article mainly focuses on the utilization of shadowed type-2 fuzzy systems used to achieve the goal of dynamically adapting the parameters of two already known algorithms in the literature: the harmony search and the differential evolution algorithms. It has already been established that type-2 fuzzy logic enhances the performance of metaheuristics by enabling parameter adaptation; however, the utilization of fuzzy logic results in an increased execution time. For this reason, in this article, the shadowed type-2 fuzzy approach is put forward as a way of reducing execution time, while maintaining the good results that the complete type-2 fuzzy model produces. The harmony search and differential evolution algorithms with shadowed type-2 parameter adaptations were applied to the problem of optimally designing fuzzy controllers. The simulations were performed with the controllers working in an ideal situation, and then with a real situation under different noise levels in order to reach a conclusion regarding the performance of each of the algorithms that were applied.
Stability Analysis and Robust Stabilization of Uncertain Fuzzy Time-Delay Systems
Authors: Chao Chun-Tang , Chen Ding-Horng , Chiou Juing-Shian
Published: October 2021

New sufficient conditions for delay-independent and delay-dependent robust stability of uncertain fuzzy time-delay systems based on uncertain fuzzy Takagi-Sugeno (T-S) models are presented by using the properties of matrix and norm measurements. Further sufficient conditions are formulated, in terms of the linear matrix inequalities (LMIs) of robust stabilization, and are developed via the technique of parallel distributed compensation (PDC), and then the simplification of the conditions for the controller design of uncertain fuzzy time-delay systems. The proposed methods are simple and effective. Some examples below are presented to illustrate our results.
Product Type Operators Involving Radial Derivative Operator Acting between Some Analytic Function Spaces
Authors: Devi Manisha , Raj Kuldip , Mursaleen Mohammad
Published: October 2021

Let N denote the set of all positive integers and N0=N∪{0}. For m∈N, let Bm={z∈Cm:|z|<1} be the open unit ball in the m−dimensional Euclidean space Cm. Let H(Bm) be the space of all analytic functions on Bm. For an analytic self map ξ=(ξ1,ξ2,…,ξm) on Bm and ϕ1,ϕ2,ϕ3∈H(Bm), we have a product type operator Tϕ1,ϕ2,ϕ3,ξ which is basically a combination of three other operators namely composition operator Cξ, multiplication operator Mϕ and radial derivative operator R. We study the boundedness and compactness of this operator mapping from weighted Bergman–Orlicz space AσΨ into weighted type spaces Hω∞ and Hω,0∞.
Sustainability Ranking of the Iranian Major Ports by Using MCDM Methods
Authors: Majidi Ali , Mirzapour Al-e-Hashem Seyed M. J. , Hashemkhani Zolfani Sarfaraz
Published: October 2021

The maritime industry is moving towards a sustainable supply chain (SSC), intending to increase the quality of logistics and make more profit. The sustainability of the maritime supply chain (MSC) in Iran is one of the topics that has not been widely studied. Ports play a crucial role in promoting Iran’s position in the international transit of products, strengthening economic, social, and environmental connections with neighboring eastern and northeastern countries, improving GDP, and promoting the role of the free zone in the national development of the country. Port development is one of the essential elements in the government’s strategic planning in developing and activating the East axis. It has a special priority in line with government policies based on deprivation elimination and improving people’s living standards. This paper considers five significant ports of Iran that are part of special economic zones and studies the sustainability of those ports. In this research, different multi-criteria decision-making methods were applied to solve a sustainability-ranking problem of major Iranian ports. First of all, by using the SWARA method, sub-criteria of loading and unloading oil, pier length, and population obtained the highest scores in economic, environmental, and social aspects of sustainability, respectively, which shows that they had the greatest impact on the sustainability assessment of Iranian ports. Finally, the MARCOS and CoCoSo techniques were the most similar in all three dimensions of sustainability, and both seemed to be suitable methods for evaluating the sustainability of ports. Furthermore, the implementation of sensitivity analysis and definition of different scenarios for port evaluation and the high efficiency of the MARCOS method were determined in solving the port-ranking problem. According to the MARCOS method results, economic, environmental, and social criteria were all effective criteria in the sustainable development of major Iranian ports and have been largely applied in Astara, Bushehr, and Imam Khomeini ports. Based on the analysis of the results, several managerial insights to make better industry decisions are also revealed.
Cohomologies of n-Lie Algebras with Derivations
Authors: Sun Qinxiu , Wu Zhixiang
Published: October 2021

The goal of this paper is to study cohomological theory of n-Lie algebras with derivations. We define the representation of an n-LieDer pair and consider its cohomology. Likewise, we verify that a cohomology of an n-LieDer pair could be derived from the cohomology of associated LeibDer pair. Furthermore, we discuss the (n−1)-order deformations and the Nijenhuis operator of n-LieDer pairs. The central extensions of n-LieDer pairs are also investigated in terms of the first cohomology groups with coefficients in the trivial representation.
Spatio-Temporal Spread Pattern of COVID-19 in Italy
Authors: D’Angelo Nicoletta , Abbruzzo Antonino , Adelfio Giada
Published: October 2021

This paper investigates the spatio-temporal spread pattern of COVID-19 in Italy, during the first wave of infections, from February to October 2020. Disease mappings of the virus infections by using the Besag–York–Mollié model and some spatio-temporal extensions are provided. This modeling framework, which includes a temporal component, allows the studying of the time evolution of the spread pattern among the 107 Italian provinces. The focus is on the effect of citizens’ mobility patterns, represented here by the three distinct phases of the Italian virus first wave, identified by the Italian government, also characterized by the lockdown period. Results show the effectiveness of the lockdown action and an inhomogeneous spatial trend that characterizes the virus spread during the first wave. Furthermore, the results suggest that the temporal evolution of each province’s cases is independent of the temporal evolution of the other ones, meaning that the contagions and temporal trend may be caused by some province-specific aspects rather than by the subjects’ spatial movements.
Inertial Krasnoselski–Mann Iterative Method for Solving Hierarchical Fixed Point and Split Monotone Variational Inclusion Problems with Its Applications
Authors: Chuasuk Preeyanuch , Kaewcharoen Anchalee
Published: October 2021

In this article, we discuss the hierarchical fixed point and split monotone variational inclusion problems and propose a new iterative method with the inertial terms involving a step size to avoid the difficulty of calculating the operator norm in real Hilbert spaces. A strong convergence theorem of the proposed method is established under some suitable control conditions. Furthermore, the proposed method is modified and used to derive a scheme for solving the split problems. Finally, we compare and demonstrate the efficiency and applicability of our schemes for numerical experiments as well as an example in the field of image restoration.
Sliding Group Window with Rebacking off for Collision Avoidance in High-Efficiency Wireless Networks
Authors: Almagrabi Alaa Omran , Ali Rashid , Al-Otaibi Yasser Difulah , Oqaibi Hadi Mohsen , Khurshaid Tahir
Published: October 2021

It is difficult for wireless local area networks (WLANs), IEEE 802.11ax high-efficiency WLAN (HEW), to join next-generation innovations such as 5th generation (5G) and Internet of Things (IoT) because they still have their conventional channel access mechanism as their essential medium access control (MAC) protocol. The MAC protocol uses a traditional binary exponential backoff (BEB) algorithm to access channel resources that depend on the noncognitive increment of contention parameters for collision avoidance. In BEB, the collision issue increases with the increase in connected devices in the network due to a fixed contention window size. The larger the size of the network, the larger the collision in the network. To avoid such a circumstance, in this paper, we propose a sliding group window (sGW) mechanism dependent on collision-point assessment in order to improve the performance of MAC protocol for HEW. The proposed algorithm additionally presents a rebacking off for collision avoidance (ReBOCA) system for sGW, which combines the uniform dispersion of the contention parameters. This variation of an ordinary backoff algorithm permits the reasonable sliding of the user groups in the case of collision. The algorithm explicitly accounts for the peculiarities of dense environments and backward compatibility. Key aspects of the proposed solution include collision-point estimation, rebacking off for collision distribution convergence for fair treatment, and adaptive sliding of group windows to mitigate contention unfairness. We further formulated a closed-form Markov chain model for the performance analysis of our proposed sGW with ReBOCA scheme. Theoretical and practical results prove that our proposed scheme achieved maximal efficiency, even under dense environments. An increase in throughput with a lower packet collision probability was achieved with the proposed mechanism, and the efficiency increased as the number of contending stations increased than compared to traditional BEB performance. Our proposed ReBOCA mechanism enhanced network throughput by 38.18% than compared to the conventional BEB mechanism.
Geary’s c and Spectral Graph Theory
Authors: Yamada Hiroshi
Published: October 2021

Spatial autocorrelation, of which Geary’s c has traditionally been a popular measure, is fundamental to spatial science. This paper provides a new perspective on Geary’s c. We discuss this using concepts from spectral graph theory/linear algebraic graph theory. More precisely, we provide three types of representations for it: (a) graph Laplacian representation, (b) graph Fourier transform representation, and (c) Pearson’s correlation coefficient representation. Subsequently, we illustrate that the spatial autocorrelation measured by Geary’s c is positive (resp. negative) if spatially smoother (resp. less smooth) graph Laplacian eigenvectors are dominant. Finally, based on our analysis, we provide a recommendation for applied studies.
A Quadratic–Exponential Model of Variogram Based on Knowing the Maximal Variability: Application to a Rainfall Time Series
Authors: Benavides-Bravo Francisco Gerardo , Soto-Villalobos Roberto , Cantú-González José Roberto , Aguirre-López Mario A. , Benavides-Ríos Ángela Gabriela
Published: October 2021

Variogram models are a valuable tool used to analyze the variability of a time series; such variability usually entails a spherical or exponential behavior, and so, models based on such functions are commonly used to fit and explain a time series. Variograms have a quasi-periodic structure for rainfall cases, and some extra steps are required to analyze their entire behavior. In this work, we detailed a procedure for a complete analysis of rainfall time series, from the construction of the experimental variogram to curve fitting with well-known spherical and exponential models, and finally proposed a novel model: quadratic–exponential. Our model was developed based on the analysis of 6 out of 30 rainfall stations from our case study: the Río Bravo–San Juan basin, and was constructed from the exponential model while introducing a quadratic behavior near to the origin and taking into account the fact that the maximal variability of the process is known. Considering a sample with diverse Hurst exponents, the stations were selected. The results obtained show robustness in our proposed model, reaching a good fit with and without the nugget effect for different Hurst exponents. This contrasts to previous models, which show good outcomes only without the nugget effect.