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The discovery of crude oil in a number of Sub‐Saharan African countries resulted in resource expansion that tends to have great implications for the socioeconomic development of the region. Deep poverty and low standards of living are still prevalent, in spite of the oil boom. On this premises, a panel study of six Sub‐Saharan African countries is undertaken for the period between 1983 and 2020. The goal is to identify the best ways to reduce overdependency on resource (crude oil) and enhance the socioeconomic situation of the selected countries. The linear (augmented mean group) approach and nonlinear (nonlinear autoregressive distributed lag) with relevant variables (Agricultural sector, crude oil price, government expenditure, official exchange rate, foreign direct investment, inflow, GDP, and trade openness) are employed in this study for the selected countries. The findings from both Augmented Mean Group and Nonlinear Autoregressive Distributed Lag and Granger causality attest to the resources curse on the socioeconomic development of the six countries through the contraction of their respective agricultural sectors. Crude oil price (proxy for the oil sector), trade openness, and real exchange rate are in particular found to have a negative influence on the agricultural sector. However, direct foreign investment in the agricultural sector in oil‐rich economies in Sub‐Saharan Africa is having a positive impact. This can be linked to over‐dependence on rising oil exports, which tends to crowd out non‐oil (agricultural) exports. Hence, a resource‐based policy targeted at diversification of the economies through revenue generated from crude oil is recommended. [ABSTRACT FROM AUTHOR]

In recent years, the increasing volume and complexity of ship traffic has raised the probability of collision accidents in ports, waterways, and coastal waters. Due to the relative rarity of collision accidents, near misses have been used in the research to study the collision risk in the relevant water areas. However, the factor of near miss identification is usually limited to the relative distance between ships, and the instantaneous quantification and geographical distribution of collision risk is not paid enough attention. Therefore, this article proposed a domain-based regional collision risk model that can quantify the collision risk by detecting near miss scenarios. The proposed model is capable of quantifying the collision risk in the water area instantaneously and periodically and can be used to depict the geographical distribution of collision risks in combination with a grid method and the spatial interpolation technique. To validate the proposed model, some experimental case studies were carried out using automatic identification system (AIS) data from the Bohai Strait. The results show the capability and advantage of the proposed model in regional collision risk identification and visualization, which is helpful for maritime surveillance when monitoring and organizing ship traffic and may therefore contribute to the improvement of maritime safety. [ABSTRACT FROM AUTHOR]

Most of the known ionic electrical components are fabricated from petroleum-based raw materials and are not recyclable or degradable. A necessary solution involving the green fabrication of ionic conductors, which requires efficiency, scalability, and environmental friendliness, should be developed. Herein, we prepared a liquid-free dynamic polymer network based on the biobased monomer thioctic acid. Through simple and efficient copolymerization, the synthetic performance of the ionic conductive elastomer was effectively adjusted. With its high transparency, good extensibility, and ideal conductivity, the synthetic elastomer was applied in a strain sensor to detect the movements of organisms. Due to its dynamic disulfide bonds and various noncovalent interactions, the synthetic ionic conductive elastomer exhibited an intrinsic self-healing ability, a desirable recyclability, and certain degradability. This research provides a new perspective and method for coordinating synthetic efficiency, multilevel structures, and overall performance of smart materials for soft electronic devices. [ABSTRACT FROM AUTHOR]

With the increasing volume of ship traffic, maritime traffic safety is facing a great challenge because the traffic in port becomes more and more crowded and complicated, which will make ship collisions more likely to happen. As a special water area of the port, the anchorage is also threatened by collision risk all the time. For accurately assessing the collision risk in anchorage and its adjacent waters in real time, this paper proposed an analytic model based on Automatic Identification System (AIS) data. The proposed anchorage collision risk model was established in microscopic, macroscopic, and complexity aspects, which considered ship relative motion, anchorage characteristics, and ship traffic complexity, respectively. For validation, the AIS data of the anchorages near the Shandong Peninsular were used to carry out a series of experiments. The results show that the proposed model can identify the anchorage collision risk effectively and has an advantage in dealing with complicated scenarios. The proposed anchorage collision risk model can help maritime surveillance better monitor and organize the ship traffic near the port and provide mariners with a reference about the collision risk situation of the anchorage on their route, which are important to improving maritime traffic safety. [ABSTRACT FROM AUTHOR]

The snake-like robot is a limbless bionic robot widely used in unstructured environments to perform tasks with substantial functional flexibility and environmental adaptability in complex environments. In this paper, the spiral climbing motion of a snake-like robot on the outer surface of a cylindrical object was studied based on the three-dimensional motion of a biological snake, and we carried out the analysis and optimization of the motion-influencing factors. First, the spiral climbing motion of the snake-like robot was implemented by the angle control method, and the target motion was studied and analyzed by combining numerical and environmental simulations. We integrated the influence of kinematics and dynamics factors on the spiral climbing motion. Based on this, we established a multi-objective optimization function that utilized the influence factors to optimize the joint module. In addition, through dynamics simulation analysis, the change of the general clamping force of the snake-like robot's spiral climbing motion was transformed into the analysis of the contact force between the joint module and the cylinder. On the basis of the results, the effect of the control strategy adopted in this paper on the motion and change rule of the spiral climbing motion was analyzed. This paper presents the analysis of the spiral climbing motion, which is of great theoretical significance and engineering value for the realization of the three-dimensional motion of the snake-like robot. [ABSTRACT FROM AUTHOR]

With the rapid development of the shipping industry in recent years, the increasing volume of ship traffic makes marine traffic much busier and more crowded, especially in the waterway off the coast. This leads to the increment of the complexity level of marine traffic and poses more threats to marine traffic safety. In order to study marine traffic safety under the conditions of increasing complexity, this article proposed a marine traffic complexity model based on the method in molecular dynamics. The model converted ship traffic to a particle system and identified the traffic complexity by analyzing the radial distribution of dynamic and spatial parameters of ships in a Euclid plane. The effectiveness of the proposed model had been validated by the case studies in the waters of Bohai Strait with real AIS (Automatic Identification System) data and simulated data. The results show that the proposed model can evaluate the marine traffic complexity more sufficiently and accurately. The proposed model is helpful for marine surveillance operators to monitor and organize marine traffic under complex situations so as to improve marine traffic safety. [ABSTRACT FROM AUTHOR]

A modern class of self‐healing polyphosphazene elastomers has been synthesized using coordination bonds for the first time. Two categories of carboxyl‐modified polyphosphazene have been synthesized, and 16 cross‐linked polymers have been fabricated by tuning the concentration of different metal ions, which also allows modifying the properties of the elastomer by adjusting the interactions. This design enables the polymer network to form a hierarchical and dynamic structure without introducing complex ligands. The polyphosphazene networks can be toughened and enhanced by the dynamic coordination structure. Due to the distinct design, the synthesized elastomers show unprecedented properties in halogen‐free polyphosphazenes, including high tensile stress (1.82 MPa), high malleability (≈1100%), shape memory, self‐healing, and thermal processing capacity. [ABSTRACT FROM AUTHOR]

This paper discusses modifications to the commercially available SPICE 2 program that allow the accurate simulation of thyristor circuits. A near-ideal switch model of a thyristor is developed using resistive components, thus eliminating the problems associated with transistor models. The simulator SPICE 2G.6 is modified and a new input format for the thyristor is implemented. Examples of simulations with the new model agree closely with theoretical and experimental investigations.

Ship density is widely accepted as a basic and major indicator to reflect the marine traffic situation, but it has some limitations in representing the compactness and complexity of ship traffic. To overcoming these limitations, the paper proposes a novel ship density model based on the radial distribution function in molecular dynamics. The proposed model can identify the density and compactness of traffic around each ship and then map the ship density from a microscopic perspective. In addition, the proposed model can identify the global density and the complexity of ship traffic to some extent in the macroscopic perspective. Utilising case studies, the effectiveness of the proposed model is validated through the analysis of ship density in several regions in the Bohai Strait area. The proposed model is developed to help marine surveillance operators gain a better understanding of the traffic situation and to assist them in their work, eventually contributing to navigational safety. [ABSTRACT FROM AUTHOR]

SUMMARY In this paper, the principles of the three-phase saturated transformer coupling new-type solid state fault current limiter (SSFCL) are studied using the equivalent circuit method; in addition, considering the nonlinearity of the iron core material in the saturated transformer, the circuit field-coupled 3-D finite-element analysis is employed to investigate the transient performance of the proposed SSFCL. The analysis and simulation results show that the novel SSFCL has negligible impact on the power system during the normal operating stage, automatic response to the short-circuit fault, and especially low secondary voltage level during the current-limiting stage, which are of great significance to the reduction of the thyristor voltage level, the DC reactance, as well as the volume and cost of the whole SSFCL. The current-limiting effect is also tested in the simulation of a multi-machine power system with the protection of SSFCL. Last, the comparison of the simulation and experimental results proves the feasibility of the proposed SSFCL. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Marine traffic survey is a fundamental part of marine traffic engineering. In the assessment of the safety or effectiveness in particular water areas, the distribution of ship tracks is always included as one of the most significant results of a marine traffic survey. In this paper, methods of marine traffic survey are discussed and an appropriate method is selected to obtain the traffic data considering the available research circumstances in China. A semiautomatic artificial way of plotting a distribution diagram of ship tracks is presented with illustrations. Details of the diagram plotted by using the collected traffic data are described for reference. [ABSTRACT FROM AUTHOR]

In order to avoid collision, ships usually take collision avoidance manoeuvres, such as course alteration. However, the effect of such a manoeuvre is influenced by ship manoeuvrability. This paper proposed an improved danger sector model to identify the collision risk between two encountering ships. The proposed model is improved from the danger sector model, which is based on a course alteration manoeuvre by taking ship manoeuvrability into consideration. To involve ship manoeuvrability in the proposed model, the turning circle of a ship is determined when it calculates the size of the danger sector. For validating the proposed model, the Automatic Identification System (AIS) data in the northern Yellow Sea of China were used to carry out some experiments of different encountering scenarios. The results show that the proposed improved danger sector model can identify the collision risk between two encountering ships effectively and has advantages compared with the original danger sector model. The proposed model can help mariners and maritime surveillance operators have a more accurate and effective assessment of ship collision risk in the water area, which can contribute to the improvement of navigational safety. [ABSTRACT FROM AUTHOR]

A reliable estimation of the floating condition of a roll on/roll off cargo (ROPAX) vessel after the accumulation of firewater on the vehicle deck is extremely important for making correct decisions on evacuation and abandonment. Thus, for the seafarer working on a ROPAX vessel, there is a demand for a time-dependent prediction of the floating condition of the vessel after the firewater accumulation. For this purpose, a new iterative computational approach, based on quasi-static theory, is presented. The approach is examined through the records observed in an accident of the M/V Dashun. The results show that the approach has good accuracy and feasibility provided that the actual heeling angle and cargo shift during the accident are carefully monitored. [ABSTRACT FROM AUTHOR]

tRFs and tiRNAs (tRNA-derived fragments) are an emerging class of small noncoding RNAs produced by the precise shearing of tRNAs in response to specific stimuli. They have been reported to regulate the pathological processes of numerous human cancers. However, the biofunction of tRFs and tiRNAs in the development and progression of papillary thyroid cancer (PTC) has not been reported yet. In this study, we aimed to explore the biological roles of tRFs and tiRNAs in PTC and discovered that a novel 5'tRNA-derived fragment called tRF-1:30-Gly-CCC-3 (tRF-30) was markedly down-regulated in PTC tissues and cell lines. Functionally, tRF-30 inhibited the proliferation and invasion of PTC cells. Mechanistically, tRF-30 directly bound to the biotin-dependent enzyme pyruvate carboxylase (PC), downregulated its protein level, interfered with the TCA cycle intermediate anaplerosis, and thus affected metabolic reprogramming and PTC progression. These findings revealed a novel regulatory mechanism for tRFs and a potential therapeutic target for PTC., (© 2023 Fu et al.)

Elymus sibiricus L. is a perennial forage species that has potential to serve as a forage source in livestock grazing systems. However, E. sibiricus has been shown to have a rapid and substantial reduction of aboveground biomass and seed yield after 3 or 4 years and an accelerated aging process. To determine possible aging mechanisms, we planted E. sibiricus seeds in triplicate blocks in 2012, 2015, and 2016, respectively, and harvested samples of leaves and roots at the jointing and heading stages in 2018 and 2019 to determine oxidative indices and endogenous hormones. The fresh aboveground biomass of 4- and 5-year old plants declined by 34.2% and 52.4% respectively compared with 3-year old plants, and the seed yield declined by 12.7% and 34.1%, respectively. The water content in leaves was 51.7%, 43.3%, and 35.6%, and net photosynthesis was 7.73, 6.35, and 2.08 µmol/m 2 ·s in 3-, 4-, and 5-year old plants, respectively. The superoxide anion radical generation rate in leaves and roots did not show any aging pattern. There was a non-significant increase in malondialdehyde concentration with plant age, particularly in leaves and roots at the heading stage in 2019. The superoxide dismutase activity showed a declining trend with age of plant roots at the jointing stage in both 2018 and 2019. The peroxidase activity declined with plant age in both leaves and roots, for example, and the catalase activity in roots 4- and 7-year old plants declined by 13.8% and 0.85%, respectively, compared to 3-year old plants at the heading stage in 2018. Therefore, the reduced capacity of the antioxidant system may lead to oxidative stress during plant aging process. Overall, the concentrations of plant hormones, auxin (IAA), gibberellin (GA), zeatin (ZT), and abscisic acid (ABA) were significantly lower in roots than in leaves. The IAA concentration in leaves and roots exhibited different patterns with plant age. The ZT concentrations in leaves of 3-year old plants was 2.39- and 2.62-fold of those in 4- and 7-year old plants, respectively at the jointing stage, and in roots, the concentration declined with plant age. The changes in the GA concentration with plant age varied between the physiological stages and between years. The ABA concentrations appeared to increase with plant age, particularly in leaves. In conclusion, the aging process of E. sibiricus was apparently associated with an increase in oxidative stress, a decrease of ZT and an increase of ABA, particularly in roots. These findings highlight the effects of plant age on the antioxidant and endogenous hormone activity of E. sibiricus . However, these plant age-related trends showed variations between plant physiological stages and between harvest years that needs to be researched in the future to develop strategies to manage this forage species., Competing Interests: The authors declare that they have no competing interests., (© 2023 Qi et al.)