Probe nuclear structure using the anisotropic flow at the Large Hadron Collider

Recent studies have shown that the shape and radial profile of the colliding nuclei have strong influences on the initial condition of the heavy ion collisions and the subsequent development of the anisotropic flow. Using A Multi-Phase Transport model (AMPT) model, we investigated the impact of nuclear quadrupole deformation $\beta_2$ and nuclear diffuseness $a_0$ of $^{129}$Xe on various of flow observables in Xe--Xe collisions at \sqrtnn = 5.44 TeV. We found that $\beta_2$ has a strong influence on central collisions while $a_0$ mostly influences the mid-central collisions. The relative change of flow observables induced by a change in $\beta_2$ and $a_0$ are also found to be insensitive to the values of parameters controlling the strength of the interaction among final state particles. Our study demonstrates the potential for constraining the initial condition of heavy ion collisions using future system scans at the LHC.Comment: 25 pages, for the EPJA Topical Issue

Effect of seed pre-treatment with plant growth compound regulators on seedling growth under drought stress

Saabunud / Received 28.10.2021 ; Aktsepteeritud / Accepted 10.12.2021 ; Avaldatud veebis / Published online 11.12.2021 ; Vastutav autor / Corresponding author: Andrii Melnyk [email protected] experiment aimed to evaluate the effect of different compound regulators on the germination rate, seedling morphology of two mustard (Brassica juncea L.) cultivars ('Felicia' and 'Prima') under simulated drought stress with PEG-6000. The eight commercial growth compound regulators (ALBIT, VERMISTIMD, ANTISTRESS, AGRINOS, REGOPLAN, BIOFOGE, STIMULATE, and FAST START) were pretreated seeds at recommended doses. The application of growth regulators promoted the growth of seedlings under drought stress but had no obvious effect on the germination rate of the two varieties. The root fresh weight, total root length, leaf area, stem length, and stem volume in 'Felicia' significantly increased with ANTISTRESS treatment by 24.28, 3.30, 24.70, 19.40, and 30.90%. In addition, the number of lateral roots reached the maximum with AGRINOS and REGOPLAN treatment compared with plants without regulators under drought conditions, which were 135.55 and 121.20%, respectively. For 'Prima', the application of FAST START had a remarkable effect on root fresh weight, total root length, lateral root number and primary root length, root surface area, leaf area, and stem volume by 17.62, 18.12, 211.20, 53.75, 28.57, 15.90, and 32.30%, respectively

Towards Universal Languages for Tractable Ontology Mediated Query Answering

An ontology language for ontology mediated query answering (OMQA-language) is universal for a family of OMQA-languages if it is the most expressive one among this family. In this paper, we focus on three families of tractable OMQA-languages, including first-order rewritable languages and languages whose data complexity of the query answering is in AC0 or PTIME. On the negative side, we prove that there is, in general, no universal language for each of these families of languages. On the positive side, we propose a novel property, the locality, to approximate the first-order rewritability, and show that there exists a language of disjunctive embedded dependencies that is universal for the family of OMQA-languages with locality. All of these results apply to OMQA with query languages such as conjunctive queries, unions of conjunctive queries and acyclic conjunctive queries.Comment: 10 pages, 1 figure, the full version of a paper accepted for AAAI 2020. Some typos have been correcte

Phylogenetic structure and formation mechanism of shrub communities in arid and semiarid areas of the Mongolian Plateau

The mechanisms of species coexistence within a community have always been the focus in ecological research. Community phylogenetic structure reflects the relationship of historical processes, regional environments, and interactions between species, and studying it is imperative to understand the formation and maintenance mechanisms of community composition and biodiversity. We studied the phylogenetic structure of the shrub communities in arid and semiarid areas of the Mongolian Plateau. First, the phylogenetic signals of four plant traits (height, canopy, leaf length, and leaf width) of shrubs and subshrubs were measured to determine the phylogenetic conservation of these traits. Then, the net relatedness index (NRI) of shrub communities was calculated to characterize their phylogenetic structure. Finally, the relationship between the NRI and current climate and paleoclimate (since the Last Glacial Maximum, LGM) factors was analyzed to understand the formation and maintenance mechanisms of these plant communities. We found that desert shrub communities showed a trend toward phylogenetic overdispersion; that is, limiting similarity was predominant in arid and semiarid areas of the Mongolian Plateau despite the phylogenetic structure and formation mechanisms differing across habitats. The typical desert and sandy shrub communities showed a significant phylogenetic overdispersion, while the steppified desert shrub communities showed a weak phylogenetic clustering. It was found that mean winter temperature (i.e., in the driest quarter) was the major factor limiting steppified desert shrub phylogeny distribution. Both cold and drought (despite having opposite consequences) differentiated the typical desert to steppified desert shrub communities. The increase in temperature since the LGM is conducive to the invasion of shrub plants into steppe grassland, and this process may be intensified by global warming