In this paper, the swarming behavior of multiple Euler-Lagrange systems with cooperation-competition interactions is investigated, where the agents can cooperate or compete with each other and the ...parameters of the systems are uncertain. The distributed stabilization problem is first studied, by introducing an auxiliary system to each agent, where the common assumption that the cooperation-competition network satisfies the digon sign-symmetry condition is removed. Based on the input-output property of the auxiliary system, it is found that distributed stabilization can be achieved provided that the cooperation subnetwork is strongly connected and the parameters of the auxiliary system are chosen appropriately. Furthermore, as an extension, a distributed consensus tracking problem of the considered multiagent systems is discussed, where the concept of equi-competition is introduced and a new pinning control strategy is proposed based on the designed auxiliary system. Finally, illustrative examples are provided to show the effectiveness of the theoretical analysis.
In this paper, a reverse group consensus problem is investigated for the dynamic agents with the inputs in the cooperation-competition network which can be divided into two sub-networks. The weights ...between the agents in the same sub-network are positive, while the weights between the agents among different sub-networks are negative. Then, the reverse group consensus is firstly studied without the in-degree balance condition. By defining the mirror graph and establishing the solution of the multi-agent system, it is found that the reverse group consensus problem can be achieved if the mirror graph is strongly connected. The explicit expression of the error level is also derived, which would be vanished for multi-agent systems with some special kinds of inputs. Furthermore, as an extension, the decomposing of the cooperation-competition network is discussed, where the concept of the condensation undirected graph and the path balance condition are defined, and several effective sufficient conditions are obtained. Finally, numerical simulation demonstrates the effectiveness of the theoretical analysis.
The gut microbiota plays an integral role in the metabolism and immunity of animal hosts, and provides insights into the health and habitat assessment of threatened animals. The skywalker hoolock ...gibbon (Hoolock tianxing) is a newly described gibbon species, and is considered an endangered species. Here, we used 16S rRNA amplicon sequencing to describe the fecal bacterial community of skywalker hoolock gibbons from different habitats and in captivity. Fecal samples (n = 5) from two captive gibbons were compared with wild populations (N = 6 gibbons, n = 33 samples). At the phylum level, Spirochetes, Proteobacteria, Firmicutes, Bacteroidetes dominated in captive gibbons, while Firmicutes, Bacteroidetes, and Tenericutes dominated in wild gibbons. At the genus level, captive gibbons were dominated by Treponema-2, followed by Succinivibrio and Cerasicoccus, while wild gibbons were dominated by Anaeroplasma, Prevotellaceae UCG-001, and Erysipelotrichaceae UCG-004. Captive rearing was significantly associated with lower taxonomic alpha-diversity, and different relative abundance of some dominant bacteria compared to wild gibbons. Predicted Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that captive gibbons have significantly lower total pathway diversity and higher relative abundance of bacterial functions involved in "drug resistance: antimicrobial" and "carbohydrate metabolism" than wild gibbons. This study reveals the potential influence of captivity and habitat on the gut bacterial community of gibbons and provides a basis for guiding the conservation management of captive populations.
Cost-effective and earth-abundant oxygen evolution reaction (OER) electrocatalysts are an incredible research hotspot in numerous energy storage and conversion technology fields. Herein, CoS2/MoS2 ...nanosheets supported by carbon cloth as a dual-active CC@CoS2/MoS2 heterostructure electrocatalyst is prepared through a simple solvothermal method. The catalyst demonstrates admirable OER performance in 1 M KOH solution with a low overpotential of 243 mV at a current density of 10 mA cm–2 and a minor Tafel slope of 109 mV dec–1, displaying honorable stability after 1000 cyclic voltammetry (CV) cycles and long-term robustness over 60 h. Theoretical calculations further ascertain that the rate-determining step of the electrocatalytic course of the CC@CoS2/MoS2 heterostructure is the conversion *O + OH– → *OOH + e– with a lower energy barrier of 1.49 eV due to the heterojunction established by CoS2 and MoS2, which can promote the OER performance of electrocatalysts. The actual identification of the catalytic mechanism in the heterostructure is conducive to the improvement of electrocatalysis applications in the OER.
Social Synchrony on Complex Networks Xuan, Qi; Zhang, Zhi-Yuan; Fu, Chenbo ...
IEEE transactions on cybernetics,
05/2018, Letnik:
48, Številka:
5
Journal Article
Recenzirano
Social synchrony (SS) is an emergent phenomenon in human society. People often mimic others which, over time, can result in large groups behaving similarly. Drawing from prior empirical studies of SS ...in online communities, here we propose a discrete network model of SS based on four attributes: 1) depth of action; 2) breadth of impact, i.e., a large number of actions are performed with a large group of people involved; 3) heterogeneity of role, i.e., people of higher degree play more important roles; and 4) lastly, emergence of phenomenon, i.e., it is far from random. We analyze our model both analytically and with simulations, and find good agreement between the two. We find this model can well explain the four characters of SS, and thus hope it can help researchers better understand human collective behavior.
Gut microbiota influences nutrient metabolism and immunity of animal hosts. Better understanding of the composition and diversity of gut microbiota contributes to conservation and management of ...threatened animals both in situ and ex situ. In this study, we applied 16S rRNA gene amplicon sequencing to evaluate the composition and diversity of the fecal bacterial community of four gibbon genera (Family Hylobatidae) at four Chinese zoos. The results showed that the dominant bacterial phyla were Bacteroidetes, Firmicutes, and Proteobacteria and dominant families were Prevotellaceae (Bacteroidetes), Spirochaetaceae (Spirochaetes) and Ruminococcaceae (Firmicutes) in the gut of all gibbons. Both captive site and host genus had significant effects on the relative abundance of dominant bacteria and structure of gut bacterial community. We found that captive site and host genus did not solely impact gut bacterial diversity, but the interaction between them did. This study provides basic knowledge for gut microbiota of all four gibbon genera and contributes to management and conservation of captive gibbons.
Silver nanoclusters (AgNCs) have been widely applied in the field of biology, drug therapy and cell imaging in the last decade. In order to study the biosafety of AgNCs, GSH-AgNCs and DHLA-AgNCs were ...synthesized using glutathione (GSH) and dihydrolipoic acid (DHLA) as ligands, and their interactions with calf thymus DNA (ctDNA) from abstraction to visualization were studied. The results of spectroscopy, viscometry and molecular docking demonstrated that GSH-AgNCs mainly bound to ctDNA in a groove mode, while DHLA-AgNCs were both groove and intercalation binding. Fluorescence experiments suggested that the quenching mechanism of both AgNCs to the emission of ctDNA-probe were both in static mode, and thermodynamic parameters demonstrated that the main forces between GSH-AgNCs and ctDNA were hydrogen bonds and van der Waals forces, while hydrogen bonds and hydrophobic forces contributed to the binding of DHLA-AgNCs to ctDNA. The binding strength demonstrated that DHLA-AgNCs bound to ctDNA more strongly than that of GSH-AgNCs. The results of circular dichroism (CD) spectroscopy reflected small effects of both AgNCs on the structure of ctDNA. This study will support the theoretical foundation for the biosafety of AgNCs and have a guiding significance for the preparation and application of AgNCs.
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•The effect of ligand structure on the properties of silver nanoclusters was studied.•The mechanism of the interaction between silver nanoclusters and ctDNA was systematically investigated.•By combining experiments with molecular docking, the experimental results were visualized and credibility was improved.•Providing a new methodology for biosafety studies of ultra-small nanomaterials.•The influence of ligand functional groups on the interaction forces was investigated.
1. Flowering plants exhibit striking interspecific and intraspecific variation in flower number, which strongly influences the reproductive success of animal-pollinated plants. However, the ...reproductive consequences of producing a single flower are poorly understood. 2. Here, we test if plants producing a single flower have a reproductive disadvantage compared with plants producing multiple flowers by combining field investigation of five deceptive orchids and a survey of published literature. Pollen limitation was estimated by comparing fruit production between hand pollination and open pollination. Flowering frequency was monitored over years to assess the potential advantage of producing a single flower. 3. Both single- and multiple-flowered species suffered strong pollen limitation. However, single-flowered species had significantly lower fruit set and produced fewer seeds per individual, although they had a significantly higher pollen removal than species with multiple flowers. A phylogenetically independent contrast of 28 species representing four of the five subfamilies of Orchidaceae revealed that fruit set was significantly positively associated with flower number. Both pollen removal and fruit set had a positive relationship with flower number within the multipleflowered species. 4. Synthesis. Current data and phylogenetically independent contrast support the hypothesis that producing a single flower has reproductive disadvantages. Single-flowered species may compensate for low female success through high flowering frequency over years. This study provides insight into costs and benefits of producing a single flower in deceptive orchids.
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