课程文献中心 更多>>

关键词： Environment Kuznets Curve (EKC)   Ecological footprint   Carbon emission   Energy intensity   Biomass energy consumption   RENEWABLE ENERGY-CONSUMPTION   KUZNETS CURVE HYPOTHESIS   CARBON EMISSIONS EVIDENCE   DIOXIDE CO2 EMISSIONS   FINANCIAL DEVELOPMENT   ECOLOGICAL FOOTPRINT   NONRENEWABLE ENERGY   EMPIRICAL-EVIDENCE   NUCLEAR-ENERGY   EKC HYPOTHESIS  

摘要： This study quantifies the Environment Kuznets curve?s validity against two different environment proxies, the ecological footprint and carbon emissions for selected seventeen Western Asia and North African countries over the period 1980 to 2017. The study employs the Interactive Fixed Effect (IFE) and Dynamic Common Correlated Effect (D-CCE) to quantify the long-run association among variables in a multiplicative framework. The empirical outcomes indicate that the inverted U-shaped hypothesis is not valid for carbon emission; however, it holds for ecological footprint. The results show that energy intensity and financial development are environment-friendly indicators. Likewise, biomass energy consumption exposes a negative and statistically significant influence on proxies of environmental degradation. Causality findings reveal bidirectional causal links between economic development and its square to emission, biomass energy consumption, and financial development; also, bidirectional causality has been observed from energy intensity to biomass energy in the first model. Moreover, for the second model, causality has been seen from biomass energy consumption, economic development, and its square to ecological footprint, keeping the same two-way relationship among explanatory variables as in the first model. Policymakers should focus on the policy options to increase energy efficiency to get a clean environment.

关键词： Giant cell   Myocarditis   Heart failure   Mechanical support device   Ventricular tachycardia  

摘要： This report reviews the management of a case of Giant Cell Myocarditis (GCM) that presented with cardiogenic shock. This case highlights the importance of a multi-disciplinary approach to the care of these patients including the use of a mechanical circulatory support (MCS) device. (c) 2021 Elsevier Inc. All rights reserved.

关键词： Climbing mechanism   Abundance   Functional diversity   Forest degradation   Freestanding lianas   FUNCTIONAL TRAITS   LAND-USE   RAIN-FOREST   LIGHT INTERCEPTION   TREE REGENERATION   SPECIES-DIVERSITY   NATIONAL-PARK   GROWTH   GAPS   ABUNDANCE  

摘要： Subtropical forests have been under constant pressure due to drastic changes in land use, fragmentation, and logging. These impacts can alter the canopy cover, structure, species composition, and functional characteristics of plant communities. Here, we assess whether structural and functional properties of the liana community change in forests that were differently disturbed in the past. For this purpose, six 1-ha plots were established in closed and open canopy forests in the Atlantic Forest of Northern Argentina. Lianas were measured and identified and plant material was collected to determine specific leaf area, leaf dry matter content, and wood density. Species richness of lianas was similar, but the abundance and basal area were significantly higher in open canopy than in closed canopy plots. This difference was primarily the result of a higher abundance of scramblers in open canopy plots, while tendrilled lianas were negatively affected by low tree density and basal area. The abundance of large scrambler lianas was lower in sites with high tree density. On the other hand, scramblers had lower wood density and leaf dry matter content than tendril climbers and twiners had the lowest specific leaf area values. Consequently, liana communities in open canopy forests were associated with a rapid resource acquisition strategy and lower functional diversity which could be possibly driven by changes in environmental variables typical of large gaps (light availability, temperature, and soil fertility). Our results highlight a shift in liana climbing mechanisms and in the function of liana communities in disturbed forest, becoming dominated by lianas with similar functional traits. Future studies should assess the relative importance of changes of liana communities shedding light on climbing-type-level effects on tree growth and forest functioning.

关键词： positioning technology   GNSS   positioning accuracy   traffic density   driving safety   SYSTEMS   GNSS   GPS   PERFORMANCE   MOVEMENT   BEHAVIOR  

摘要： Based on Global Navigation Satellite Systems (GNSS) and Internet of Vehicles (IoV), collision warning systems can provide drivers specific warning information such as the position of hazardous vehicles. However, positioning technologies vary in accuracy. Highly accurate positioning technologies are theoretically favorable for driving safety but are relatively difficult to use widely due to the high cost. While many researchers compared accuracies of different positioning technologies or explored methods to improve accuracy, few directly investigated the effect of different positioning accuracies for hazardous vehicles on driving safety. The present study conducted a laboratory experiment to explore the effect of four positioning accuracies of hazardous vehicles (i.e., highest: 1.5 m, high: 5 m, medium: 8.5 m, and low: 20 m, each value represented the radius of a circle and the estimated positions of hazardous vehicle were within this circle) and different traffic densities (high: one car per 150 m and low: one car per 1500 m) on driver behaviors. Thirty participants were distributed into high and low traffic density groups. Each participant received auditory warning information, which provided positions of hazardous vehicles relative to the ego vehicle concerning four accuracy levels. Driving safety (i.e., number of collisions and min TTC), driving performance (i.e., brake onset reaction time, steer onset reaction time, and mean deceleration), and subjective workload for warnings with different positioning accuracies of hazardous vehicles were recorded and analyzed. Results suggested the following: 1) Under low traffic density, four positioning accuracies showed no significant differences on driving safety and performance as well as subjective workload. 2) Under high traffic density, the medium positioning accuracy (8.5 m) exerted no significant differences on driving safety and performance compared with the highest positioning accuracy (1.5 m), which had the fastes

关键词： Driver assessment   Racing   Information processing   Situation awareness   Posture   SITUATION AWARENESS   MODEL   PERFORMANCE   SPEED  

摘要： Future vehicles may drive automatically in a human-like manner or contain systems that monitor human driving ability. Algorithms of these systems must have knowledge of criteria of good and safe driving behavior with regard to different driving styles. In the current study, interviews were conducted with 30 drivers, including driving instructors, engineers, and race drivers. The participants were asked to describe good driving on public roads and race tracks, and in some questions were supported with video material. The results were interpreted with the help of Endsley's model of situation awareness. The interviews showed that there were clear differences between what was considered good driving on the race track and good driving on the public road, where for the former, the driver must touch the limit of the vehicle, whereas, for the latter, the limit should be avoided. However, in both cases, a good driver was characterized by self-confidence, lack of stress, and not being aggressive. Furthermore, it was mentioned that the driver's posture and viewing behavior are essential components of good driving, which affect the driver's prediction of events and execution of maneuvers. The implications of our findings for the development of automation technology are discussed. In particular, we see potential in driver posture estimation and argue that automated vehicles excel in perception but may have difficulty making predictions. (c) 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://***/licenses/by/4.0/).

关键词： Turbot   Sex determination   GWAS   sox2   Interfamily variation   Genome assembly   Oxford Nanopore   DIFFERENTIATION   EVOLUTION   SEQUENCE   FISH   GENE   RNA   PLEURONECTIFORMES   IDENTIFICATION   RESOURCES   ALIGNMENT  

摘要： Background: Understanding sex determination (SD) across taxa is a major challenge for evolutionary biology. The new genomic tools are paving the way to identify genomic features underlying SD in fish, a group frequently showing limited sex chromosome differentiation and high SD evolutionary turnover. Turbot (Scophthalmus maximus) is a commercially important flatfish with an undifferentiated ZW/ZZ SD system and remarkable sexual dimorphism. Here we describe a new long-read turbot genome assembly used to disentangle the genetic architecture of turbot SD by combining genomics and classical genetics approaches. Results: The new turbot genome assembly consists of 145 contigs (N50 = 22.9 Mb), 27 of them representing >95% of its estimated genome size. A genome wide association study (GWAS) identified a similar to 6.8 Mb region on chromosome 12 associated with sex in 69.4% of the 36 families analyzed. The highest associated markers flanked sox2, the only gene in the region showing differential expression between sexes before gonad differentiation. A single SNP showed consistent differences between Z and W chromosomes. The analysis of a broad sample of families suggested the presence of additional genetic and/or environmental factors on turbot SD. Conclusions: The new chromosome-level turbot genome assembly, one of the most contiguous fish assemblies to date, facilitated the identification of sox2 as a consistent candidate gene putatively driving SD in this species. This chromosome SD system barely showed any signs of differentiation, and other factors beyond the main QTL seem to control SD in a certain proportion of families.

关键词： Mission critical logistics   Logistics   Military   Service parts   Fulfillment analysis   SUPPLY CHAIN   MAINTENANCE   NETWORK  

摘要： Logistics systems that involve truncated timelines, where failure to meet such a timeline results in a substantial loss to business, have been coined 'mission critical logistics' systems, and their management is quite different from their 'traditional' counterparts. Yet, much of the research in this space has operated under the assumption that the methods, approaches, and tactics are equally applicable to both mission critical, and traditional logistics systems. Is this necessarily so? Most literature addresses functional issues such as inventory or process management but does not provide an understanding of the drivers of fulfillment performance in mission critical systems. This is a critical gap in the literature. Partnering with the Defense Logistics Agency (DLA) and the United States Navy, we studied a mission critical logistics system in order to understand the drivers of these logistics systems and their performance. We utilize a unique dataset consisting of inventory fulfillment and ordering, as well as part criticality and location. Overall the results indicate that inventory management is a much more dynamic process in mission critical logistics systems, whereby flexibility is crucial, and designation of part categories and essentiality can be the determining factor for whether or not the mission fails.

关键词： Automated guided vehicles   Multi-AGV system   Deadlock avoidance   Zone-control   Deadlock-free zone   MANUFACTURING SYSTEMS   AVOIDANCE   PREDICTION   DESIGN   ALGORITHMS  

摘要： In this paper, we present a simple, easily adaptable method for collision and deadlock resolution in transport systems. This method is based on the dividing the transport road network into non-overlapping zones, which enables it to be analyzed as a system of discrete events. The method distinguishes unidirectional zones, which have the feature that the passage between these zones cannot lead to a deadlock. This makes it possible to divide the transport network into segments composed of unidirectional zones and segments composed of other zones. The method introduces a structural on-line control policy (SOCP) which guarantees that the execution of an elementary transport operation does not lead to deadlock. This allows, in general, a global problem to be considered by means of sequentially solved local problems, thus reducing the restrictive constraints resulting from the need to avoid deadlocks. The method is suitable both for central and distributed control system architecture. The efficiency of the proposed method was verified using simulation. Its results were compared with the results of other methods. The comparison was made using examples of three systems differing in their types of roads. The presented results of the simulation studies show a higher efficiency of the SOCP method.

关键词： Ride-sharing platform   Pricing   Cross-side externalities   Sharing economy   Consumer surplus   Driver surplus   COMPETITION   SERVICE   CUSTOMERS   PRICE  

摘要： The booming on-demand ride-sharing economy induces drivers who do or do not own cars to provide services on ride-sharing platforms. To meet growing demand, in practice the platforms have cooperated with car-rental companies that rent cars to without-car drivers to improve their supplies. However, this might harm the platforms, consumers, and drivers, since such a second capacity source may increase customers' waiting time and reduce drivers' utilization. In this paper, we study the impact of without car drivers in a car-rental company on a ride-sharing platform, consumer surplus, and driver surplus. The platform must decide whether to cooperate with the car-rental company, which entails a per-service price charged to customers and a per-service wage paid to (with-car and without-car) driver. In turn, the car-rental company charges without-car drivers who would like to provide services on the platform a price, and pays a commission rate to the platform. We analyze a stylized model in which customers decide whether to use the platform based on price and expected waiting time, and drivers base decisions about whether to work for the platform on wage and the probability of getting jobs. Driven by these two features, we find that the platform would prefer to cooperate with the car-rental company, and the optimal price and wage (profit) of the platform are not necessarily monotonic (increases) in the potential number of without-car drivers or the commission paid by the company. We also find that when the commission rate is high or the fixed payout ratio is low, cooperation can yield a win-win-win outcome for the platform, customers, and drivers. This provides a plausible explanation of why most ride-sharing platforms would cooperate with car-rental companies in practice. In addition, we find that such a win-win-win outcome can easily be achieved for a large customer size or delay cost but a small (with-car and without-car) driver size or service rate. (c) 2020 Elsevier Lt