Revealing microbial processes and nutrient limitation in soil through ecoenzymatic stoichiometry and glomalin-related soil proteins in a retreating glacier forefield

The glacial retreat is observed and predicted to increase in intensity especially in high-elevation areas as a result of global warming, which leaves behind a primary succession along soil chronosequences. Although soil microbes have been recognized as main drivers of ecological and evolutionary processes, our understanding of their effects on nutrient biogeochemistry during primary succession remains limited. In this study, we investigated changes in the microbial community structure, ecoenzymatic stoichiometry, and glomalin-related soil protein (GRSP) accumulation in the Hailuogou Glacier Chronosequence, located on the eastern Tibetan Plateau. We wanted to reveal the effects of nutrient limitation on soil microbes and the relative contributions of edaphic and biotic factors. The results showed that with an increasing soil age, there was a steady increase in the microbial biomass and a shift from a bacterial to fungal dominated pattern. Soil enzyme stoichiometry and analyses on threshold elemental ratios revealed that microbial activities are limited by carbon and nitrogen during the early successional stage (3-52 years), while phosphorus was the main limiting factor during later stages (80-120 years). Moreover, the redundancy analysis and structural equation modeling suggested that during early stages edaphic factors had a greater impact on microbial processes, while the vegetation factors were most influential during the last two stages. Overall, these results highlighted the importance of integrating knowledge of the microbial community structure, soil enzyme activities and GRSP to gain a holistic view of soil-plant microbe interactions during ecosystem successions.Peer reviewe

Distinct co-occurrence patterns and driving forces of rare and abundant bacterial subcommunities following a glacial retreat in the eastern Tibetan Plateau

Unraveling the dynamics and driving forces of abundant and rare bacteria in response to glacial retreat is essential for a deep understanding of their ecological and evolutionary processes. Here, we used Illumina sequencing datasets to investigate ecological abundance, successional dynamics, and the co-occurrence patterns of abundant and rare bacteria associated with different stages of soil development in the Hailuogou Glacier Chronosequence. Abundant taxa exhibited ubiquitous distribution and tight clustering, while rare taxa showed uneven distribution and loose clustering along the successional stages. Both abundant and rare subcommunities were driven by different factors during assembly: the interactions of biotic and edaphic factors were the main driving forces, although less important for rare taxa than for the abundant ones. In particular, the redundancy analysis and structural equation modeling showed that soil organic C, pH, and plant richness primarily affected abundant subcommunities, while soil N and pH were most influential for rare subcommunities. More importantly, variation partitioning showed that edaphic factors exhibited a slightly greater influence on both abundant (7.8%) and rare (4.5%) subcommunities compared to biotic factors. Both abundant and rare bacteria exhibited a more compact network topology at the middle than at the other chronosequence stages. The overlapping nodes mainly belonged to Proteobacteria and Acidobacteria in abundant taxa and Planctomycetia, Sphingobacteriia, and Phycisphaerae in rare taxa. In addition, the network analysis showed that the abundant taxa exhibited closer relationships and more influence on other co-occurrences in the community when compared to rare taxa. These findings collectively reveal divergent co-occurrence patterns and driving forces for abundant and rare subcommunities along a glacier forefield chronosequence in the eastern Tibetan Plateau.Peer reviewe

Photosynthetic Performance and Anti-Oxidative Response of Cornus Controversa Seedlings Under Cadmium and Lead Stress

The photosynthetic efficiency of Cornus controversa leaves was decreased significantly under Cd treatment while it was not affected by Pb exposure. Cd decreased while Pb treatment increased the chlorophyll contents of Cornus controversa leaves. Furthermore, the peroxidase (GPX) activities were decreased after Cd treatment while elevated by Pb exposure in Cornus controvera seedlings. In addition, both Cd and Pb exposures increased the malondialdehyde (MDA) and proline contents and elevated the superoxide dismutase (SOD) activities of Cornus controvera seedlings. Collectively, these results indicated that Cornus controversa may be more tolerant to Pb than Cd toxicity. This finding will contribute to the evaluation of planting Cornus controversa in heavy metal polluted soil conditions

Off-Line Evaluation of Indoor Positioning Systems in Different Scenarios: The Experiences From IPIN 2020 Competition

Every year, for ten years now, the IPIN competition has aimed at evaluating real-world indoor localisation systems by testing them in a realistic environment, with realistic movement, using the EvAAL framework. The competition provided a unique overview of the state-of-the-art of systems, technologies, and methods for indoor positioning and navigation purposes. Through fair comparison of the performance achieved by each system, the competition was able to identify the most promising approaches and to pinpoint the most critical working conditions. In 2020, the competition included 5 diverse off-site off-site Tracks, each resembling real use cases and challenges for indoor positioning. The results in terms of participation and accuracy of the proposed systems have been encouraging. The best performing competitors obtained a third quartile of error of 1 m for the Smartphone Track and 0.5 m for the Foot-mounted IMU Track. While not running on physical systems, but only as algorithms, these results represent impressive achievements.Track 3 organizers were supported by the European Union’s Horizon 2020 Research and Innovation programme under the Marie Skłodowska Curie Grant 813278 (A-WEAR: A network for dynamic WEarable Applications with pRivacy constraints), MICROCEBUS (MICINN, ref. RTI2018-095168-B-C55, MCIU/AEI/FEDER UE), INSIGNIA (MICINN ref. PTQ2018-009981), and REPNIN+ (MICINN, ref. TEC2017-90808-REDT). We would like to thanks the UJI’s Library managers and employees for their support while collecting the required datasets for Track 3. Track 5 organizers were supported by JST-OPERA Program, Japan, under Grant JPMJOP1612. Track 7 organizers were supported by the Bavarian Ministry for Economic Affairs, Infrastructure, Transport and Technology through the Center for Analytics-Data-Applications (ADA-Center) within the framework of “BAYERN DIGITAL II. ” Team UMinho (Track 3) was supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope under Grant UIDB/00319/2020, and the Ph.D. Fellowship under Grant PD/BD/137401/2018. Team YAI (Track 3) was supported by the Ministry of Science and Technology (MOST) of Taiwan under Grant MOST 109-2221-E-197-026. Team Indora (Track 3) was supported in part by the Slovak Grant Agency, Ministry of Education and Academy of Science, Slovakia, under Grant 1/0177/21, and in part by the Slovak Research and Development Agency under Contract APVV-15-0091. Team TJU (Track 3) was supported in part by the National Natural Science Foundation of China under Grant 61771338 and in part by the Tianjin Research Funding under Grant 18ZXRHSY00190. Team Next-Newbie Reckoners (Track 3) were supported by the Singapore Government through the Industry Alignment Fund—Industry Collaboration Projects Grant. This research was conducted at Singtel Cognitive and Artificial Intelligence Lab for Enterprises (SCALE@NTU), which is a collaboration between Singapore Telecommunications Limited (Singtel) and Nanyang Technological University (NTU). Team KawaguchiLab (Track 5) was supported by JSPS KAKENHI under Grant JP17H01762. Team WHU&AutoNavi (Track 6) was supported by the National Key Research and Development Program of China under Grant 2016YFB0502202. Team YAI (Tracks 6 and 7) was supported by the Ministry of Science and Technology (MOST) of Taiwan under Grant MOST 110-2634-F-155-001.Peer reviewe

Increasing soil age drives shifts in plant-plant interactions from positive to negative and affects primary succession dynamics in a subalpine glacier forefield

The stress gradient hypothesis predicts that plant-plant interactions switch between facilitation (positive) and competition (negative) along environmental gradients, with facilitation being more common under high abiotic stress conditions relative to more moderate abiotic stress conditions. Our aim was to reveal, whether the interactions between Populus purdomii Rehder and Salix rehderiana Schneider switch from positive to negative during the early stages of primary succession in the Gongga Mountain glacier retreat region. We also investigated, whether soil age is a major driving factor for the transformation of interactions between neighboring plants. We analyzed differences between intraspecific interactions and interspecific interactions of Populus and Salix under 20- and 40-year-old soil conditions, including plant biomass accumulation and allocation, nutrient absorption and utilization, relative competition intensity, non-structural carbohydrates, foliar carbon and nitrogen isotope composition, mesophyll cell ultrastructure, soil microbial biomass and community structure, extracellular enzyme activities, and soil organic carbon (SOC), soil total nitrogen (TN), soil ammonium (NH4+-N), and soil nitrate (NO3--N) contents. We found that P. purdomii and S. rehderiana growing under interspecific interactions had greater contents of aboveground dry matter, belowground dry matter and total dry matter compared to intraspecific interactions in 20-year-old soil. Furthermore, in 40-year-old soil conditions, the phospholipid fatty acid (PLFA) analysis showed that Populus and Salix exposed to interspecific interactions exhibited lower amounts of gram-positive bacteria, fungi (18,1 omega 9c) and actinomycetes, and lower levels of total PLFAs than those growing under intraspecific interactions. The redundancy analysis (RDA) results demonstrated that soil N was the most important parameter contributing to the composition of microbial communities. In addition, the N-15 stable isotope labeling method showed that Populus and Salix growing under interspecific interactions had higher foliage delta N-15 derived from NO3- (delta N-15-NO3-) than those growing under intraspecific interactions in 20-year-old soil. In summary, our results demonstrated that Populus-Salix interactions exhibited positive effects on survival in 20-year-old soil. Conversely, under 40-year-old soil conditions, Populus-Salix interactions presented negative effects in relation to nutrients and elimination by neighboring plants. Moreover, soil age is a major driving factor for plant-plant interactions that shift from positive to negative with an increasing soil age in the Gongga Mountain glacier forefield. In all, our results support the stress gradient hypothesis. Our findings improve understanding of plant-plant interactions and plant-soil feedbacks during the early stages of soil development, and of the construction of vegetation communities.Peer reviewe

Effects of locational accessibility on firm diffusion characteristics: the case of Sino-Europe Economic Corridor

Regional mobility of economic production factors accelerates the globalization of the associated economies and impacts firm diffusion trends. The Belt and Road Initiative aims to facilitate the orderly flow of economic production factors along the Sino-Europe Economic Corridor. However, little is known about the effects of locational accessibility on firm relocations with such an initiative. Conceptualizing locational accessibility based on elementary production factors, this paper proposed a methodological framework to analyze the potential firm diffusion trends by applying the percolation theory in a multimodal freight supernetwork. The empirical analysis concerns two typical manufacturing industries along the Sino-Europe Economic Corridor. The results show that the percolation transition happens during the diffusion of the two manufacturing industries considering land rent, labor cost, and freight transport cost as the elementary production factors. It is found that the improvement in transport accessibility accelerates the diffusion trends of the manufacturing industries, although the bottleneck regions for the diffusion of both industries do not change comparatively. The proposed methodological framework acts as an efficient testbed for analyzing the regional diffusion trends of different types of industries

Manufacturing Diffusion Trends from the Perspective of Trade Network: the Belt vs. the Road

With the deepening of the ‘Belt and Road (B&R)’ initiative (BRI), the trends of manufacturing relocation and diffusion along the B&R has accelerated. This paper first collects bilateral trade data of 16 categories of major commodities among 55 countries along the B&R for 2017. Second, according to current and future transportation accessibility, this paper constructs two types of topological networks among countries along the B&R from the perspectives of both competitive and complementary trade. Percolation theory is adopted to analyze the manufacturing diffusion trends and bottleneck links among the two types of topological trade networks, which provides a new perspective through which to study manufacturing relocation and diffusion patterns. The results show that (1) based on current transportation accessibility, main industries percolate and agglomerate among countries with rapid economic development along the 21st Century Maritime Silk Road and that (2) the improvement in the China-Europe Railway Express (CR Express) postpones diffusion trends and improves the relocation potential of Silk Road Economic Belt regions

Determinants of wave-system structures of network airlines at hub airports

This paper attempted to analyze the factors influencing the existence and configuration of wave-system structures of large network airlines at hub airports based on the statistical data of daily flight schedules. A bootstrapped binary logistic regression model was used to analyze the relationship between wave-system structure and its influential factors. Further, a partial least squared regression model was employed to uncover the determinants of wave-system structures' configuration. It is found that the interaction effects of two types of flight rates positively determine the existence of a wave-system structure, and the rate of airline's daily flights had the biggest impact on the configurations of wave-system structures

Intermodal transportation of full and empty containers in harbor-inland regions based on revenue management

Abstract Introduction The transport of full containers and repositioning of empty containers are essential for the operation of a container logistic enterprise. In a large inland region, railway and road transportation take their own advantages for container transportation in terms of transport efficiency and costs. The combination of the two modes creates larger possibility for logistic enterprise to provide efficient service and reduce operation costs. Thus, this paper aims to optimize the inland intermodal transportation of full and empty containers. Methods Different from cost minimum model, an integer programming model is proposed based on revenue management, making the model more reasonable in practice where logistic enterprises have the right to reject transportation demands from customers considering transport profits and capacity limitations. The real cases of transportation networks of Northeast China and parts of the southern Europe are applied to evaluate and describe the model and performance. Results The results indicate that the proposed intermodal transportation optimization for both full and empty containers is feasible and profitable for logistic enterprises. The efficiency of container usage increases since we take the conversion of containers during transportation into account. Results also imply an inappropriate pricing strategy at certain inland depots in the case. Conclusions This paper provides an optimization method for the intermodal transportation of full and empty containers in harbor-inland regions / hinterlands. Different from cost minimization in the literature, this paper models the transportation problem based on revenue management. That is, the model aims to maximize profits of logistic enterprise with the specific constraints in container transportation, as well as demand rejection. The model is proofed to be feasible in the real transportation networks and can create more profits for transportation enterprises. The analysis of real cases show that the total profits can be enlarged by considering the conversion of containers during transportation. In addition, it is verified that the optimization of inland transportation of empty and full containers reduces the operating costs of logistic enterprises. Moreover, results uncover the fact that a governed pricing policy at Suifenhe is not reasonable and may deteriorate the future export environment there. For the case based on part of southern Europe, it seems that the port, customer, inland transport operator and possibly container shipping company in Europe may benefit by establishing appropriate inland depots

Identification of technology spillover among airport alliance from the perspective of efficiency evaluation: the case of China

The development of airport alliances has undergone hardships, although airport alliances have emerged simultaneously with other airline alliances in an attempt to improve competitiveness. Technology spillover is a major benefit of airport alliances, but the effects of such spillover are not as obvious as might be expected. This paper proposes a three-stage DEA-based methodological framework to uncover the existence and characteristics of technology spillover among allied airports, and identify whether the technology spillover of airport alliances outperforms the self-development of airports. A case study that concerns multi-airport companies and non-allied airports in China, where airports and airlines are rapidly expanding, is included. The results show that the technology spillover of airport alliances does not become wide spread among all of the allied airports, which is most likely because civil aviation in China is still in a stage of rapid development. However, such spillover does appear among small- and mid-sized allied airports in cities with fast urban economic development. Finally, the related implications of our methodological framework are discussed along with our findings