5,112 research outputs found

    A minimal U(1)β€²U(1)^\prime extension of MSSM in light of the B decay anomaly

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    Motivated by the RKR_K and RKβˆ—R_{K^*} anomalies from B decays, we extend the minimal supersymmetric model with a non-universal anomaly-free U(1)β€²U(1)^\prime gauge symmetry, coupling non-universally to the lepton sector as well as the quark sector. In particular, only the third generation quarks are charged under this U(1)β€²U(1)^\prime, which can easily evade the dilepton bound from the LHC searches. An extra singlet is introduced to break this U(1)β€²U(1)^\prime symmetry allowing for the ΞΌ\mu-term to be generated dynamically. The relevant constraints of Bsβˆ’BΛ‰sB_s-\bar{B}_s mixing, D0βˆ’DΛ‰0D^0-\bar{D}^0 mixing and the LHC dilepton searches are considered. We find that in the allowed parameter space this U(1)β€²U(1)^\prime gauge interaction can accommodate the RKR_K and RKβˆ—R_{K^*} anomalies and weaken considerably the Zβ€²Z^\prime mass limits while remaining perturbative up to the Planck scale.Comment: 12 pages,2 figure

    N-[11-(4-ChloroΒ­phenΒ­yl)-11,12-dihydroΒ­benzo[c]phenanthridin-6-yl]benzamide

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    There are two independent molΒ­ecules in the asymmetric unit of the title compound, C30H21ClN2O, which differ slightly in the orientation of the unsubstituted phenyl ring. InterΒ­molecular Cβ€”Hβ‹―Ο€ interΒ­actions stabilize the crystal structure. The crystal studied was found to be a racemic twin. The dihedral angles between the substituted phenyl ring and the benzo[c]phenanthridine system are 87.13β€…(5) and 79.25β€…(5)Β° in the two molecules

    Multimodal estimation of distribution algorithms

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    Taking the advantage of estimation of distribution algorithms (EDAs) in preserving high diversity, this paper proposes a multimodal EDA. Integrated with clustering strategies for crowding and speciation, two versions of this algorithm are developed, which operate at the niche level. Then these two algorithms are equipped with three distinctive techniques: 1) a dynamic cluster sizing strategy; 2) an alternative utilization of Gaussian and Cauchy distributions to generate offspring; and 3) an adaptive local search. The dynamic cluster sizing affords a potential balance between exploration and exploitation and reduces the sensitivity to the cluster size in the niching methods. Taking advantages of Gaussian and Cauchy distributions, we generate the offspring at the niche level through alternatively using these two distributions. Such utilization can also potentially offer a balance between exploration and exploitation. Further, solution accuracy is enhanced through a new local search scheme probabilistically conducted around seeds of niches with probabilities determined self-adaptively according to fitness values of these seeds. Extensive experiments conducted on 20 benchmark multimodal problems confirm that both algorithms can achieve competitive performance compared with several state-of-the-art multimodal algorithms, which is supported by nonparametric tests. Especially, the proposed algorithms are very promising for complex problems with many local optima

    Ecology of Yuqing County Carbon Sink Calculation and Ecosystem Protection Measures

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    Based on the remote sensing statistical data of land use of terrestrial ecosystems in Yuqing County, this paper calculates the amount of carbon sinks in the county according to the existing carbon sink carbon density index, compares the amount of different types of carbon sinks, and analyzes their respective carbon sink potential. The results show that the forest carbon sink is the largest, about 2.2 million tons, accounting for 75% of the total carbon sink in the county, showing the great potential of forest vegetation to absorb CO2 through photosynthesis, followed by the carbon sink produced by dry land (cultivated land), about 400,000 tons, accounting for 13% of the total carbon sink in the county; Although the amount of wetland aquatic carbon sink is small, its carbon density is very large, and it has the advantages of short renewal time and fast carbon sink, so it has great potential and can be artificially regulated to increase carbon sink. Based on the above research and analysis, combined with the spirit of the national carbon peak and carbon neutral policy and the natural law of ecosystem development, three measures to protect and increase carbon sinks in terrestrial ecosystems were put forward: (1) continuing to carry out forestry planting and do a good job in forestry protection; (2) stabilizing the surface water area and developing aquatic carbon sinks; (3) Establish a long-term monitoring system to ensure the contribution of carbon sinks, provide support for the protection of ecosystem and the development of carbon sink potential in Yuqing County from two aspects of science and management, and compare the amount of different types of carbon sinks, and analyze their carbon sink potential. On this basis, combined with the spirit of the national carbon peak and carbon neutral policy and the natural law of ecosystem development, three kinds of terrestrial ecosystem carbon sink protection and increase wording were put forward accordingly, which provided support for ecosystem protection and carbon sink potential development in Yuqing County from two aspects of science and management
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