bluuebunny/crossref_metadata_2025 huggingface dataset:
Ecofriendly and Electrically Conductive Cementitious Composites Using Melamine-Functionalized Biochar from Waste Coffee Beans
Authors: Jeong Junyoung , Jeon Giyoung , Ryu Seongwoo , Lee Joo Ha
Published: June 2022

Owing to the increasing generation of waste coffee powder and the biochar from this waste being considered as alternative conductive carbon fillers, we developed eco-friendly and electrically conductive cementitious composites using biochar from waste coffee beans, which were directly pyrolyzed into eco-friendly and electrically conductive biochar. Via carbonization and graphitization, cyclic organic carbon precursors were transformed into sp2-bonded carbon structures and then functionalized with melamine. The non-covalent functionalization process driven by the electromagnetic process accelerated the mass production and enhanced the monodispersive properties of the cementitious composites. Thus, the melamine-functionalized biochar cementitious composites exhibited an electrical conductivity of 3.64 × 10−5 ± 1.02 × 10−6 S/cm (n = 6), which corresponded to an improvement of over seven orders of that of pure concrete. Furthermore, the percolation threshold of biochar was between 0.02 and 0.05 wt.%; thus, an effective conductive network could be formed using low additions of functionalized biochar. As a result, in this study, electrically conductive cementitious composites were developed using waste coffee powder converted into carbon nanomaterials through a newly introduced process of non-covalent functionalization with melamine.
Conception, Discovery, Invention, Serendipity and Consortia: Cyanobiphenyls and Beyond
Authors: Goodby John W. , Cowling Stephen J.
Published: June 2022

In the 1960s, a world-wide change in electronic devices was about to occur with the invention of integrated circuits. The chip was upon us, which instantly created the need for a revolution in visual communication displays. From the watch to the computer monitor, to TVs, to the phone, nearly all everyday applications were affected. A strange connection in technology underpinned these changes; the linkage between silicon semiconductors and organic compounds that did not know if they were solids or liquids. Liquid crystals had been known since 1888 and had seen little usage until they were inserted between conducting glass slides and an applied electric field. Suddenly, the possibility of driving images with low voltage fields became obvious. Many major companies took up the challenge of commercialisation, but in the UK a curious combination of government research facilities, electronic companies and one small university came together in 1970 to form a consortium and within two years the basis for new technologies had been founded. Chemistry is part of this story, with new conceptions, discoveries and inventions, and the luck to be in the right place at the right time.
Process of Au-Free Source/Drain Ohmic Contact to AlGaN/GaN HEMT
Authors: Zhang Lin-Qing , Wu Xiao-Li , Miao Wan-Qing , Wu Zhi-Yan , Xing Qian , Wang Peng-Fei
Published: June 2022

AlGaN/GaN high electron mobility transistors (HEMTs) are regarded as promising candidates for a 5G communication system, which demands higher frequency and power. Source/drain ohmic contact is one of the key fabrication processes crucial to the device performance. Firstly, Au-contained metal stacks combined with RTA high-temperature ohmic contact schemes were presented and analyzed, including process conditions and contact formation mechanisms. Considering the issues with the Au-contained technique, the overview of a sequence of Au-free schemes is given and comprehensively discussed. In addition, in order to solve various problems caused by high-temperature conditions, novel annealing techniques including microwave annealing (MWA) and laser annealing (LA) were proposed to form Au-free low-temperature ohmic contact to AlGaN/GaN HEMT. The effects of the annealing method on surface morphology, gate leakage, dynamic on-resistance (RON), and other device characteristics are investigated and presented in this paper. By using a low-temperature annealing atmosphere or selective annealing method, gate-first Si-CMOS compatible AlGaN/GaN HEMT technology can be realized for high frequency and power application.
The Bioconcentration and the Translocation of Heavy Metals in Recently Consumed Salicornia ramosissima J. Woods in Highly Contaminated Estuary Marshes and Its Food Risk
Authors: Sanjosé Israel , Navarro-Roldán Francisco , Montero Yina , Ramírez-Acosta Sara , Jiménez-Nieva Francisco Javier , Infante-Izquierdo María Dolores , Polo-Ávila Alejandro , Muñoz-Rodríguez Adolfo Francisco
Published: June 2022

Salicornia species are halophyte plants that are an important source for food, pharmacy, and bioenergy. They can be consumed as a leafy vegetable, but they can accumulate heavy metals that carry a health risk when knowledge of how each species behaves in different types of soil is lacking. This present work aimed to determine to what extent S. ramosissima can be cultivated as food in estuaries contaminated by heavy metals and to what extent it can be used in phytoremediation works, by studying its behavior in populations that grow naturally in contaminated soils. We analyzed accumulation and translocation in different parts of the plant for 14 heavy metals and calculated the Health Risk Index value associated with their consumption as a leafy vegetable. The results obtained mean that the S. ramosissima plants that grow in most of the soils of this estuary are unfit for human consumption in some of the populations studied. In conclusion, Salicornia ramosissima J. Woods can accumulate Cd, As, and Pb—among other metals—in its leaves so its consumption should be limited to plants that grow in soils free of these metals.
Nomogram Predicting the Survival of Young-Onset Patients with Colorectal Cancer Liver Metastases
Authors: Cheng Xiaofei , Li Yanqing , Chen Dong , Xu Xiangming , Liu Fanlong , Zhao Feng
Published: June 2022

Background: Although the global prevalence of colorectal cancer (CRC) is decreasing, there has been an increase in incidence among young-onset individuals, in whom the disease is associated with specific pathological characteristics, liver metastases, and a poor prognosis. Methods: From 2010 to 2016, 1874 young-onset patients with colorectal cancer liver metastases (CRLM) from the Surveillance, Epidemiology, and End Results (SEER) database were randomly allocated to training and validation cohorts. Multivariate Cox analysis was used to identify independent prognostic variables, and a nomogram was created to predict cancer-specific survival (CSS) and overall survival (OS). Receiver operating characteristic (ROC) curve, C-index, area under the curve (AUC), and calibration curve analyses were used to determine nomogram accuracy and reliability. Results: Factors independently associated with young-onset CRLM CSS included primary tumor location, the degree of differentiation, histology, M stage, N stage, preoperative carcinoembryonic antigen level, and surgery (all p < 0.05). The C-indices of the CSS nomogram for the training and validation sets (compared to TNM stage) were 0.709 and 0.635, and 0.735 and 0.663, respectively. The AUC values for 1-, 3-, and 5-year OS were 0.707, 0.708, and 0.755 in the training cohort and 0.765, 0.735, and 0.737 in the validation cohort, respectively; therefore, the nomogram had high sensitivity, and was superior to TNM staging. The calibration curves for the training and validation sets were relatively consistent. In addition, a similar result was observed with OS. Conclusions: We developed a unique nomogram incorporating clinical and pathological characteristics to predict the survival of young-onset patients with CRLM. This may serve as an early warning system allowing doctors to devise more effective treatment regimens.
Predictors for COVID-19 Complete Remission with HRCT Pattern Evolution: A Monocentric, Prospective Study
Authors: Manolescu Diana , Timar Bogdan , Bratosin Felix , Rosca Ovidiu , Citu Cosmin , Oancea Cristian
Published: June 2022

There are growing concerns that some COVID-19 survivors may acquire fibrosis and other irreversible lung abnormalities. The purpose of this prospective study was to assess the rate and predictors of complete resolution of COVID-19 pneumonia by pursuing a hypothetical relation between time and imaging pattern evolution using HRCT findings. A monocentric prospective cohort study with a consecutive-case enrolment design was implemented during a five-month period, having a total of 683 post-COVID patients eligible for inclusion and 635 evaluations with complete follow-up for chest HRCT. The target for post-COVID evaluations consisted of performing HRCT 90 days after a confirmed SARS-CoV-2 infection. The studied patients had an average age of 54 years, ranging between 18 and 85 years old, and an average duration from the first symptoms until HRCT was performed of 74 days. At the post-COVID follow-up, 25.8% had a complete imagistic remission. The most common appearance with HRCT was “ground glass” in 86.6% in patients with persistent COVID-19, followed by reticulations, present in 78.8%, and respectively pleural thickening in 41.2% of cases. The mean total HRCT scores were statistically significantly higher in patients older than 65 years (10.6 ± 6.0) compared to the 40–65 group (6.1 ± 6.1) and the 18–40 age group (2.7 ± 4.8) (p < 0.001). Chest HRCT is a “time window” in documenting temporal persistent radiologic features of lung injury 90 days after SARS-CoV-2 infection, determining the pathologic basis of so-called “long COVID”. The complete remission was associated with a significantly higher average follow-up period and a significantly lower average patient age. Persistent HRCT features of ground glass, reticulation, and pleural thickening are associated with a higher total CT score and older age.
Long Term Cell Immune Response to COVID-19 Vaccines Assessment Using a Delayed-Type Hypersensitivity (DTH) Cutaneous Test
Authors: Barrios Yvelise , Alava-Cruz Cristina , Franco Andres , Matheu Victor
Published: June 2022

Objective: As we progress with mass vaccination against SARS-CoV-2, there are key questions about the immunogenicity of COVID-19 vaccines that still are not answered. Conventional methods to measure cellular immune responses are complex and expensive in a pandemic situation. Patients and methods: Forty healthy healthcare workers accepted to participate during the vaccination schedule with a mRNA vaccine against SARS-CoV-2. Measurement of Delayed-Type Hypersensitivity (DTH) cutaneous response after intradermal test of protein S of SARS-CoV-2 at day 35 and day 200 was performed. At the same time, a specific anti-RBD IgG using a classic ELISA before vaccination, and on days 0, 35, and 200 was performed. Results: All 40 individuals had a positive DTH skin response at day 35, whereas 39 participants had a positive skin test at day 200. Moreover, although all 40 individuals showed a positive humoral response of specific IgG against spike protein at day 35, with most of them having significantly lower levels at day 200. Conclusion: DTH could be proposed as an ideal and easy method to predict cellular immunity response to mRNA vaccines 200 days after starting an immunization schedule with mRNA vaccine for COVID-19.
Head-to-Head Comparison of 5 Anti-SARS-CoV-2 Assays Performance in One Hundred COVID-19 Vaccinees, over an 8-Month Course
Authors: Swadźba Jakub , Anyszek Tomasz , Panek Andrzej , Chojęta Agnieszka , Wyrzykowska Kinga , Martin Emilia
Published: June 2022

The immunoassays used to measure anti-spike SARS-CoV-2 antibodies are widely available on the market. However, their performance in COVID-19 vaccinees is not yet adequately assessed. Our study provides a head-to-head comparison of five methods: Abbott’s S1-RBD IgG, Roche’s S1-RBD total antibody, Euroimmun’s S1 IgG, and DiaSorin’s TrimericS IgG and S1/S2 IgG assays. Testing was performed in one hundred vaccinated subjects, at eight timepoints over eight months after vaccination. The results differed substantially between methods; however, they correlated strongly and demonstrated the individuals’ responses to both doses of vaccination and the waning of humoral immunity after eight months. Importantly, we encountered a high percentage of results above the assay-specific upper quantitation limit (UQL) for undiluted samples. This was the most pronounced for the Roche’s and Euroimmun’s assays. The Abbott’s assay showed the lowest percentage of results above the UQL. We also attempted to find a common way to establish antibody concentrations that might be classified as high. However, this resulted in between 10% and 100% of such results for different methods on day 240′. This highlights the need for an assay-specific approach for adjusting the cut-offs that may indicate COVID-19 immunity.
Airflow Obstruction in Adults with Williams Syndrome and Mice with Elastin Insufficiency
Authors: Kronquist Elise K. , Kaur Maninder , Gober Leah M. , Knutsen Russell H. , Fu Yi-Ping , Yu Zu-Xi , Donahue Danielle R. , Chen Marcus Y. , Osgood Sharon , Raja Neelam , Levin Mark D. , Barochia Amisha , Kozel Beth A.
Published: June 2022

Williams–Beuren syndrome (WS) results from the deletion of 25–27 coding genes, including elastin (ELN), on human chromosome 7q11.23. Elastin provides recoil to tissues; emphysema and chronic obstructive pulmonary disease have been linked to its destruction. Consequently, we hypothesized that elastin insufficiency would predispose to obstructive features. Twenty-two adults with WS (aged 18–55) and controls underwent pulmonary function testing, 6 min walk, and chest computed tomography (CT). Lung and airspace dimensions were assessed in Eln+/− and control mice via microCT and histology. The forced expiratory volume in 1 s (FEV1) and the ratio of FEV1 to forced vital capacity (FVC) were lower in adults with WS (p < 0.0001 and p < 0.05, respectively). The FEV1/FVC ratio was more frequently below the lower limit of normal in cases (p < 0.01). The ratio of residual volume to total lung capacity (RV/TLC, percent predicted) was higher in cases (p < 0.01), suggesting air trapping. People with WS showed reduced exercise capacity (p < 0.0001). In Eln+/− mice, ex vivo lung volumes were increased (p < 0.0001), with larger airspaces (p < 0.001). Together these data show that elastin insufficiency impacts lung physiology in the form of increased air trapping and obstruction, suggesting a role for lung function monitoring in adults with WS.
The Management of Poststroke Thalamic Pain: Update in Clinical Practice
Authors: Ri Songjin
Published: June 2022

Poststroke thalamic pain (PS-TP), a type of central poststroke pain, has been challenged to improve the rehabilitation outcomes and quality of life after a stroke. It has been shown in 2.7–25% of stroke survivors; however, the treatment of PS-TP remains difficult, and in majority of them it often failed to manage the pain and hypersensitivity effectively, despite the different pharmacotherapies as well as invasive interventions. Central imbalance, central disinhibition, central sensitization, other thalamic adaptative changes, and local inflammatory responses have been considered as its possible pathogenesis. Allodynia and hyperalgesia, as well as the chronic sensitization of pain, are mainly targeted in the management of PS-TP. Commonly recommended first- and second-lines of pharmacological therapies, including traditional medications, e.g., antidepressants, anticonvulsants, opioid analgesics, and lamotrigine, were more effective than others. Nonpharmacological interventions, such as transcranial magnetic or direct current brain stimulations, vestibular caloric stimulation, epidural motor cortex stimulation, and deep brain stimulation, were effective in some cases/small-sized studies and can be recommended in the management of therapy-resistant PS-TP. Interestingly, the stimulation to other areas, e.g., the motor cortex, periventricular/periaqueductal gray matter, and thalamus/internal capsule, showed more effect than the stimulation to the thalamus alone. Further studies on brain or spinal stimulation are required for evidence.
Ensemble Models for Tick Vectors: Standard Surveys Compared with Convenience Samples
Authors: Kessler William H. , De Jesus Carrie , Wisely Samantha M. , Glass Gregory E.
Published: June 2022

Ensembles of Species Distribution Models (SDMs) represent the geographic ranges of pathogen vectors by combining alternative analytical approaches and merging information on vector occurrences with more extensive environmental data. Biased collection data impact SDMs, regardless of the target species, but no studies have compared the differences in the distributions predicted by the ensemble models when different sampling frameworks are used for the same species. We compared Ensemble SDMs for two important Ixodid tick vectors, Amblyomma americanum and Ixodes scapularis in mainland Florida, USA, when inputs were either convenience samples of ticks, or collections obtained using the standard protocols promulgated by the U.S. Centers for Disease Control and Prevention. The Ensemble SDMs for the convenience samples and standard surveys showed only a slight agreement (Kappa = 0.060, A. americanum; 0.053, I. scapularis). Convenience sample SDMs indicated A. americanum and I. scapularis should be absent from nearly one third (34.5% and 30.9%, respectively) of the state where standard surveys predicted the highest likelihood of occurrence. Ensemble models from standard surveys predicted 81.4% and 72.5% (A. americanum and I. scapularis) of convenience sample sites. Omission errors by standard survey SDMs of the convenience collections were associated almost exclusively with either adjacency to at least one SDM, or errors in geocoding algorithms that failed to correctly locate geographic locations of convenience samples. These errors emphasize commonly overlooked needs to explicitly evaluate and improve data quality for arthropod survey data that are applied to spatial models.
Impact of Polymerization Technique and ZrO2 Nanoparticle Addition on the Fracture Load of Interim Implant-Supported Fixed Cantilevered Prostheses in Comparison to CAD/CAM Material
Authors: Alshahrani Faris A. , Hamid Shorouq Khalid , Alghamdi Lujain Ali , Alqarawi Firas K. , Al-Dulaijan Yousif A. , AlRumaih Hamad S. , Alalawi Haidar , Al Ghamdi Maram A. , Alzoubi Fawaz , Gad Mohammed M.
Published: June 2022

ZrO2 nanoparticles (ZNPs) have excellent physical properties. This study investigated the fracture load of implant-supported, fixed cantilevered prosthesis materials, reinforced with ZNPs and various polymerization techniques, compared with conventional and CAD/CAM materials. Sixty specimens were made from two CAD/CAM; milled (MIL) (Ceramill TEMP); and 3D-printed (NextDent Denture 3D+). Conventional heat-polymerized acrylic resin was used to fabricate the other specimens, which were grouped according to their polymerization technique: conventionally (HP) and autoclave-polymerized (AP); conventionally cured and reinforced with 5 wt% ZNPs (HPZNP); and autoclave reinforced with 5 wt% ZNPs (APZNP). The specimens were thermocycled (5000 cycles/30 s dwell time). Each specimen was subjected to static vertical loading (1 mm/min) using a universal Instron testing machine until fracture. Scanning electron microscopy was used for fracture surface analyses. The ANOVA showed significant fracture load differences between all the tested groups (p = 0.001). The Tukey post hoc tests indicated a significant difference in fracture load between all tested groups (p ˂ 0.001) except HP vs. HPZNP and AP vs. MIL. APZNP had the lowest mean fracture load value (380.7 ± 52.8 N), while MIL had the highest (926.6 ± 82.8 N). The CAD/CAM materials exhibited the highest fracture load values, indicating that they could be used in long-term interim prostheses. Autoclave polymerization improved fracture load performance, whereas ZrO2 nanoparticles decreased the fracture load performance of cantilevered prostheses.
Periodontal and Peri-Implant Health Status in Traditional vs. Heat-Not-Burn Tobacco and Electronic Cigarettes Smokers: A Systematic Review
Authors: D’Ambrosio Francesco , Pisano Massimo , Amato Alessandra , Iandolo Alfredo , Caggiano Mario , Martina Stefano
Published: June 2022

The aim of the present systematic review was to evaluate and possibly differentiate the effects of traditional cigarettes, heat-not-burn tobacco, and electronic cigarettes on periodontal and peri-implant health status. Electronic cigarettes and heat-not-burn tobacco have become very popular in recent years and have been proposed to consumers as a safer alternative to conventional tobacco smoke, although their effect on periodontal and peri-implant health remains unclear. The study protocol was developed according to PRISMA guidelines, and the focus question was formulated according to the PICO strategy. A literature search was conducted across PubMed/MEDLINE and the COCHRANE library from 2003 to April 2022. From the 1935 titles initially identified, 18 articles were finally included in the study and extracted data were qualitatively synthesized. It may be carefully concluded that e-cigarettes may cause attenuated clinical inflammatory signs of periodontitis and, hypothetically, of peri-implantitis when compared to conventional tobacco smoke. Both alternative smoking products, containing nicotine, may likewise exert negative effects on periodontal and peri-implant health, as demonstrated by in vitro studies. Further investigations are needed to assess the impact of electronic cigarettes and heat-not-burn tobacco products on periodontal and peri-implant health status.
Influence on Implant Bone Healing of a Collagen Membrane Placed Subjacent the Sinus Mucosa—A Randomized Clinical Trial on Sinus Floor Elevation
Authors: Morimoto Akihiro , Kobayashi Nobuhiro , Ferri Mauro , Iezzi Giovanna , Piattelli Adriano , Fortich Mesa Natalia , Botticelli Daniele
Published: June 2022

Background: Perforation of the sinus mucosa is quite a frequent complication that might occur during sinus floor elevation. The perforation is often protected with a collagen membrane to avoid the extrusion of graft particles within the sinus. However, this procedure might hinder the innate osteogenic potential of the sinus mucosa. Hence, the aim of the study was to evaluate the influence of a placement of a collagen membrane subjacent the Schneiderian membrane during sinus floor elevation on implant bone healing. Methods: Twenty volunteers took part in the trial. Ten were randomly included in the group that received a collagen membrane subjacent the sinus mucosa (Mb group), and ten did not receive the membrane (non-Mb group). A collagenated corticocancellous porcine bone was used to fill the elevated space. Six 6 months after the sinus floor elevation, a mini implant was placed transcrestally and retrieved after a further 3 months. Histological analyses were then performed on the full body of the mini implant as well as on its coronal and apical portions. Results: The new bone apposition proportion onto the implant surface was similar in the Mb and non-Mb groups, both in the apical and coronal portions of the mini implants. A lesser amount of graft was found in contact with the surface. New bone density around the mini implants were similar both in the apical and coronal portions. However, a statistically higher proportion of graft particles was found in the Mb group compared to the non-membrane group. Conclusions: The placement of a collagen membrane subjacent the sinus mucosa did not affect bone healing at implants and bone density.
Level Compressibility of Certain Random Unitary Matrices
Authors: Bogomolny Eugene
Published: June 2022

The value of spectral form factor at the origin, called level compressibility, is an important characteristic of random spectra. The paper is devoted to analytical calculations of this quantity for different random unitary matrices describing models with intermediate spectral statistics. The computations are based on the approach developed by G. Tanner for chaotic systems. The main ingredient of the method is the determination of eigenvalues of a transition matrix whose matrix elements equal the squared moduli of matrix elements of the initial unitary matrix. The principal result of the paper is the proof that the level compressibility of random unitary matrices derived from the exact quantisation of barrier billiards and consequently of barrier billiards themselves is equal to 1/2 irrespective of the height and the position of the barrier.
From Chaos to Ordering: New Studies in the Shannon Entropy of 2D Patterns
Authors: Legchenkova Irina , Frenkel Mark , Shvalb Nir , Shoval Shraga , Gendelman Oleg V. , Bormashenko Edward
Published: June 2022

Properties of the Voronoi tessellations arising from random 2D distribution points are reported. We applied an iterative procedure to the Voronoi diagrams generated by a set of points randomly placed on the plane. The procedure implied dividing the edges of Voronoi cells into equal or random parts. The dividing points were then used to construct the following Voronoi diagram. Repeating this procedure led to a surprising effect of the positional ordering of Voronoi cells, reminiscent of the formation of lamellae and spherulites in linear semi-crystalline polymers and metallic glasses. Thus, we can conclude that by applying even a simple set of rules to a random set of seeds, we can introduce order into an initially disordered system. At the same time, the Shannon (Voronoi) entropy showed a tendency to attain values that are typical for completely random patterns; thus, the Shannon (Voronoi) entropy does not distinguish the short-range ordering. The Shannon entropy and the continuous measure of symmetry of the patterns demonstrated the distinct asymptotic behavior, while approaching the close saturation values with the increase in the number of iteration steps. The Shannon entropy grew with the number of iterations, whereas the continuous measure of symmetry of the same patterns demonstrated the opposite asymptotic behavior. The Shannon (Voronoi) entropy is not an unambiguous measure of order in the 2D patterns. The more symmetrical patterns may demonstrate the higher values of the Shannon entropy.
A Time Two-Mesh Compact Difference Method for the One-Dimensional Nonlinear Schrödinger Equation
Authors: He Siriguleng , Liu Yang , Li Hong
Published: June 2022

The nonlinear Schrödinger equation is an important model equation in the study of quantum states of physical systems. To improve the computing efficiency, a fast algorithm based on the time two-mesh high-order compact difference scheme for solving the nonlinear Schrödinger equation is studied. The fourth-order compact difference scheme is used to approximate the spatial derivatives and the time two-mesh method is designed for efficiently solving the resulting nonlinear system. Comparing to the existing time two-mesh algorithm, the novelty of the new algorithm is that the fine mesh solution, which becomes available, is also used as the initial guess of the linear system, which can improve the calculation accuracy of fine mesh solutions. Compared to the two-grid finite element methods (or finite difference methods) for nonlinear Schrödinger equations, the numerical calculation of this method is relatively simple, and its two-mesh algorithm is implemented in the temporal direction. Taking advantage of the discrete energy, the result with O(τC4+τF2+h4) in the discrete L2-norm is obtained. Here, τC and τF are the temporal parameters on the coarse and fine mesh, respectively, and h is the space step size. Finally, some numerical experiments are conducted to demonstrate its efficiency and accuracy. The numerical results show that the new algorithm gives highly accurate results and preserves conservation laws of charge and energy. Furthermore, by comparing with the standard nonlinear implicit compact difference scheme, it can reduce the CPU time without loss of accuracy.
The Determinants of Competitiveness in Global Palm Oil Trade
Authors: Tandra Hansen , Suroso Arif Imam , Syaukat Yusman , Najib Mukhamad
Published: June 2022

Palm oil is an essential commodity used in the manufacture of various daily products and is highly competitive with vegetable oil. However, the palm oil competition is fierce and complex due to movement of palm oil trade. The study examined the determinant, stability, and duration of competitiveness in the global palm oil trade involving countries worldwide. This research was analyzed from 1996 to 2019 using descriptive analysis, panel regression, stability, and Kaplan–Meier tests. The results showed that palm oil supply in the global market is centralized with distributed demand. The competitiveness of palm oil based on revealed symmetric comparative advantage (RSCA) and trade balance index (TBI) is similar to its suppliers globally. The positive factors that determine the competitiveness in the global palm oil trade are population and import of animal or vegetable fats and oils. GDP per capita and dummy RSPO negatively affect competitiveness. The stability and duration analysis showed that the global palm oil market is highly competitive.
Recovery Measures for the Tourism Industry in Andalusia: Residents as Tourist Consumers
Authors: Cruz-Ruiz Elena , Ruiz-Romero de la Cruz Elena , Caballero-Galeote Lidia
Published: June 2022

The pandemic caused by the coronavirus continues to test barriers around the world. In this sense, the tourism industry has become the sector most affected by the crisis with more than 900 million euros in losses. Recovery will require a great effort, especially in countries where the sector accounts for a large share of the economy and employment. This study analyzes the perceptions and proposals of the residents of the autonomous community of Andalusia. A total of 658 surveys were conducted during the closure. A quantitative and qualitative thematic analysis was carried out using SPSS and NVivo Pro programs. The findings provide significant insights into the economic recovery of society after the pandemic. The Andalusians have opted for local tourism so that the residents become the consumers of the tourist products of their territory. The deployment of new technologies and marketing campaigns should provide the basic strategies for structural changes and innovations. The residents demand a united Europe and disagree with the statements of some political leaders. The conclusions have practical and theoretical implications for tourist destinations.
Business Incentives for Local Economic Development
Authors: Trinajstić Maša , Nižić Marinela Krstinić , Denona Bogović Nada
Published: June 2022

The main role of local development policy is to create a favorable business environment and new jobs, thus contributing to economic development. Creating a positive business environment to act as a pull factor for new businesses is of great importance, because entrepreneurship conduces to the rise in the supply of goods and to an increase in citizens’ income and revenues of local budgets. This paper therefore examines the main goals of economic development in the towns and municipalities of the Republic of Croatia, as well as the tools used by local governments to encourage entrepreneurship and new businesses. Using a questionnaire, mayors and deputies of towns and municipalities were surveyed, and the sample covered 131 towns and municipalities. The research methodology included a descriptive analysis and the Kruskal–Wallis test. The results indicate that improving the quality of life of the residents, creating new jobs, and retaining the residents in the town or municipality were identified as the most important goals of economic development. To encourage entrepreneurship and new jobs, towns and municipalities most often simplify regulations, reduce local taxes, and introduce various benefits and incentives. The contribution of the paper is manifested in providing useful guidance to local governments to improve the business environment.
Impact of COVID-19 on the Russian Labor Market: Comparative Analysis of the Physical and Informational Spread of the Coronavirus
Authors: Rodionov Dmitriy , Ivanova Anastasia , Konnikova Olga , Konnikov Evgenii
Published: June 2022

The aim of the article is to investigate the impact of the new coronavirus infection on the Russian labor market and to suppose the actions to be taken to minimize negative economic consequences. The distinctiveness of this study is the differentiation of the impact of the physical and informational spread of COVID-19. The informational spread of coronavirus is measured through the dynamics of news messages related to the topic of “coronavirus” in the largest Russian media. The analysis of the average level of wages by type of economic activity, as well as the demand of employers and the number of vacancies, allow testing the hypothesis that the physical and informational spread of coronavirus caused an increase in the number of unemployed, a decrease in average wages in the studied range of economic activities, an increase in supply on the labor market, and a decrease in demand for employees. Another task of the study is to assess the dynamics of related search queries in Yandex (Russian biggest search engine), which can help to reveal the logic in the behavior of the Russian people during the pandemic as well as to understand if the Russian economy, the labor market, and society were prepared for the changes caused by the pandemic. Using a regression modeling methodology, it was found that the influence of the information environment, namely the informational spread of coronavirus, had an even greater impact on studied parameters than the physical spread. A “delay effect of physical consequences” was discovered. The conclusions obtained showed that in the conditions of wide informatization of society, it is necessary to systematically influence the physical and informational spread of coronavirus to minimize the negative consequences of the pandemic on the labor market.
A Review Research on Tourism in the Green Economy
Authors: Toubes Diego R. , Araújo-Vila Noelia
Published: June 2022

Following the publication of the 2011 United Nations Environment Programme (UNEP) Green Economy Report, the UNWTO published the Tourism in the Green Economy report as clear evidence of the tourism sector’s growing influence on green economy. This paper provides the first narrative review on green tourism economy based on all available published research. The paper synthesizes existing knowledge, reviews responses and initiatives on green tourism, and suggests future research and methodological approaches to help advance this field. The Scopus and WoS databases were used for the bibliometric study. The results are structured into three sections—challenges, opportunities, and enabling conditions—which comprehensively cover the main themes.
The Perceptions of Student Teachers of Online Pedagogical Courses and Assessment Practices in Finnish Subject Teacher Education
Authors: Mäkipää Toni , Hildén Raili , Samulin Tanja
Published: June 2022

The purpose of this case study was to explore how student teachers at the University of Helsinki perceived pedagogical courses in emergency remote teaching. The dataset consists of the responses of 79 students to an online questionnaire and interviews with five students. Descriptive statistics, multiple linear regression analysis, and content analysis were used to analyze the data. The students pointed out that, on average, teachers have mastered the pedagogy of remote teaching well, although older teachers had more challenges than younger teachers. The quality of teaching was reported as being high. Teachers’ pedagogical knowledge was the strongest predictor of successful remote teaching. In terms of assessment, teachers mostly used essays and other written assignments to assess students’ achievement. According to most students, the assessment practices were implemented successfully. The results provide insights for developing remote teaching in teacher education.
Three-Dimensional Reconstruction Method for Bionic Compound-Eye System Based on MVSNet Network
Authors: Deng Xinpeng , Qiu Su , Jin Weiqi , Xue Jiaan
Published: June 2022

In practical scenarios, when shooting conditions are limited, high efficiency of image shooting and success rate of 3D reconstruction are required. To achieve the application of bionic compound eyes in small portable devices for 3D reconstruction, auto-navigation, and obstacle avoidance, a deep learning method of 3D reconstruction using a bionic compound-eye system with partial-overlap fields was studied. We used the system to capture images of the target scene, then restored the camera parameter matrix by solving the PnP problem. Considering the unique characteristics of the system, we designed a neural network based on the MVSNet network structure, named CES-MVSNet. We fed the captured image and camera parameters to the trained deep neural network, which can generate 3D reconstruction results with good integrity and precision. We used the traditional multi-view geometric method and neural networks for 3D reconstruction, and the difference between the effects of the two methods was analyzed. The efficiency and reliability of using the bionic compound-eye system for 3D reconstruction are proved.
Multiple Frequency Inputs and Context-Guided Attention Network for Stereo Disparity Estimation
Authors: Hua Yan , Yang Lin , Yang Yingyun
Published: June 2022

Deep learning-based methods have made remarkable progress for stereo matching in terms of accuracy. However, two issues still hinder producing a perfect disparity map: (1) blurred boundaries and the discontinuous disparity of a continuous region on disparity estimation maps, and (2) a lack of effective means to restore resolution precisely. In this paper, we propose to utilize multiple frequency inputs and an attention mechanism to construct the deep stereo matching model. Specifically, high-frequency and low-frequency information of the input image together with the RGB image are fed into a feature extraction network with 2D convolutions. It is conducive to produce a distinct boundary and continuous disparity of the smooth region on disparity maps. To regularize the 4D cost volume for disparity regression, we propose a 3D context-guided attention module for stacked hourglass networks, where high-level cost volumes as context guide low-level features to obtain high-resolution yet precise feature maps. The proposed approach achieves competitive performance on SceneFlow and KITTI 2015 datasets.
Optimal PEM Fuel Cell Model Using a Novel Circle Search Algorithm
Authors: Qais Mohammed H. , Hasanien Hany M. , Turky Rania A. , Alghuwainem Saad , Loo Ka-Hong , Elgendy Mohmmed
Published: June 2022

The aim of this article is to introduce a novel Circle Search Algorithm (CSA) with the purpose of obtaining a precise electrical model of a proton exchange membrane fuel cell (PEMFC). Current-voltage and current-power curves are used to characterize the performance of PEMFCs. A nonlinear model with seven unknown parameters is used to describe these polarization curves. Estimating these unknown parameters is a critical issue because they influence the dynamic analysis of fuel cells in a variety of applications such as transportation and smart grids. The suggested method is based on minimizing the fitness function (the sum of the squared errors (SSE)) between estimated and measured voltage values. The CSA is compared to the neural network algorithm (NNA), grey wolf optimization (GWO), and the sine cosine algorithm (SCA). The optimization results reveal that the simulation times of the CSA, NNA, GWO, and SCA are 5.2, 6, 5.8, and 5.75 s, respectively. Moreover, the CSA converges to the best minimum within the first 100 iterations, which is faster than the other algorithms. The robustness of the CSA is verified using 20 independent runs, where the CSA achieves the smallest average and standard deviation. In addition, the t-test proves the superiority of the CSA compared to the other algorithms, where all p-values are less than 5%. The simulated I-V and I-P curves of the CSA-PEMFC model match the measured curves very closely. Moreover, the efficacy of the CSA-PEMFC model is evaluated under a variety of temperature and pressure conditions. Therefore, the suggested CSA-PEMFC model has the potential to be an accurate and efficient model.
Depth Estimation of Monocular PCB Image Based on Self-Supervised Convolution Network
Authors: Huang Zedong , Gu Jinan , Li Jing , Li Shuwei , Hu Junjie
Published: June 2022

To improve the accuracy of using deep neural networks to predict the depth information of a single image, we proposed an unsupervised convolutional neural network for single-image depth estimation. Firstly, the network is improved by introducing a dense residual module into the encoding and decoding structure. Secondly, the optimized hybrid attention module is introduced into the network. Finally, stereo image is used as the training data of the network to realize the end-to-end single-image depth estimation. The experimental results on KITTI and Cityscapes data sets show that compared with some classical algorithms, our proposed method can obtain better accuracy and lower error. In addition, we train our models on PCB data sets in industrial environments. Experiments in several scenarios verify the generalization ability of the proposed method and the excellent performance of the model.
Visible-Light CDMA Communications Using Inverted Spread Sequences
Authors: Matsushima Tomoko K. , Yamasaki Shoichiro , Ono Kyohei , Tanaka Hirokazu
Published: June 2022

Visible-light communication (VLC) using light-emitting diodes (LEDs) is gaining attention in the wireless communication field. LEDs can be used as data transmitters without losing their main functionality as lighting devices. In some VLC applications, such as traffic signs and road signals in intelligent transportation systems, high brightness is required to help people recognize the signs and signals conveyed by the light sources. In this paper, the use of inverted modified prime sequence codes (MPSCs) is shown to be efficient for increasing brightness in an optical code-division multiple access (CDMA) system for VLC, while the original MPSCs, namely non-inverted codes, provide much lower brightness. The average light intensity of a system using an inverted MPSC is several times the intensity of a system using an original MPSC, without losing the capabilities of channel multiplexing and multi-user interference canceling. Average light intensity and normalized fluctuation are investigated for the optical CDMA systems with the original and inverted MPSCs. The results show that the systems with the inverted MPSCs provide higher average light intensity and lower normalized fluctuation than the systems with the original MPSCs do. Moreover, the bit error rates of the systems with the inverted MPSCs are evaluated by computer simulation and compared with those of the systems with the original MPSCs.
Resource- and Power-Efficient High-Performance Object Detection Inference Acceleration Using FPGA
Authors: Tesema Solomon Negussie , Bourennane El-Bay
Published: June 2022

The success of deep convolutional neural networks in solving age-old computer vision challenges, particularly object detection, came with high requirements in terms of computation capability, energy consumption, and a lack of real-time processing capability. However, FPGA-based inference accelerations have recently been receiving more attention from academia and industry due to their high energy efficiency and flexible programmability. This paper presents resource-efficient yet high-performance object detection inference acceleration with detailed implementation and design choices. We tested our object detection acceleration by implementing YOLOv2 on two FPGA boards and achieved up to 184 GOPS with limited resource utilization.
A 19.6–39.4 GHz Broadband Low Noise Amplifier Based on Triple-Coupled Technique and T-Coil Network in 65-nm CMOS
Authors: Wan Jiayue , Li Xiao , Han Fang , Qi Quanwen , Liu Xuzhi , Chen Zhiming
Published: June 2022

This paper presents a differential 19.6–39.4 GHz broadband low-noise amplifier (LNA) in 65-nm CMOS technology. The LNA consists of two cascode stage and one common-source stage. To achieve a wide bandwidth and low average noise figure, inter-stage peak-gain distribution technique and transformer-based triple-coupled technique are developed. Besides, a new compact T-coil-based network is proposed to neutralize the parasitic capacitors and enlarge the gain. The measure results show that the 3-dB bandwidth is from 19.6 to 39.4 GHz, the maximum gain is 23.5 dB, and the noise figure (NF) is from 3.7 to 5.8 dB. The dc power comsumption is 46 mW with 1V supply voltage. The input P1dB is −17 dBm at 30 GHz.
Multi-Objective Quantum-Inspired Seagull Optimization Algorithm
Authors: Wang Yule , Wang Wanliang , Ahmad Ijaz , Tag-Eldin Elsayed
Published: June 2022

Objective solutions of multi-objective optimization problems (MOPs) are required to balance convergence and distribution to the Pareto front. This paper proposes a multi-objective quantum-inspired seagull optimization algorithm (MOQSOA) to optimize the convergence and distribution of solutions in multi-objective optimization problems. The proposed algorithm adopts opposite-based learning, the migration and attacking behavior of seagulls, grid ranking, and the superposition principles of quantum computing. To obtain a better initialized population in the absence of a priori knowledge, an opposite-based learning mechanism is used for initialization. The proposed algorithm uses nonlinear migration and attacking operation, simulating the behavior of seagulls for exploration and exploitation. Moreover, the real-coded quantum representation of the current optimal solution and quantum rotation gate are adopted to update the seagull population. In addition, a grid mechanism including global grid ranking and grid density ranking provides a criterion for leader selection and archive control. The experimental results of the IGD and Spacing metrics performed on ZDT, DTLZ, and UF test suites demonstrate the superiority of MOQSOA over NSGA-II, MOEA/D, MOPSO, IMMOEA, RVEA, and LMEA for enhancing the distribution and convergence performance of MOPs.
A Passive but Local Active Memristor and Its Complex Dynamics
Authors: Li Fupeng , Liu Jingbiao , Zhou Wei , Dong Yujiao , Jin Peipei , Ying Jiajie , Wang Guangyi
Published: June 2022

This paper proposes a globally passive but locally active memristor, which has three stable equilibrium points and two unstable equilibrium points, exhibiting two stable locally active regions and four unstable locally active regions. We find that when the memristor operates in a stable local active region, the memristor-based second-order circuit with a parallel capacitor or a series inductor can produce periodic oscillation. Moreover, the memristor-based third-order circuit with two energy storage elements, a capacitor and an inductor, can produce complex chaotic oscillation, forming the simplest chaotic circuit.