Poly[penta­aqua­tetra­kis(μ2-nicotinato-κ2 N:O)(perchlorato-κO)lanthanum(III)disilver(I)]

In the title complex, [Ag2La(C6H4NO2)4(ClO4)(H2O)5]n, the LaIII atom, lying on a twofold rotation axis, is eight-coordinated by four O atoms from four nicotinate (nic) ligands and four water mol­ecules in a distorted square-anti­prismatic coordination geometry. The AgI atom is coordinated in an almost linear fashion by two pyridyl N atoms of two nic ligands. The linear coordination is augmented by weak inter­actions with one O atom from a half-occupied ClO4 − anion and a water mol­ecule lying on a twofold axis. Two Ag(nic)2 units connect two La atoms, forming a cyclic unit. These units are further extended into an infinite zigzag chain. The chains are bridged by the disordered perchlorate ions via weak Ag—O [2.678 (2) Å] inter­actions. O—H⋯O hydrogen bonds, weak Ag⋯Ag [3.3340 (15) Å] inter­actions and π–π inter­actions between the pyridyl rings [centroid–centroid distance = 3.656 (2) Å] lead to a three-dimensional network

3,3-Dinitro­azetidinium 2-hy­droxy­benzoate

In the title gem-dinitro­azetidinium 2-hy­droxy­benzoate salt, C3H6N3O4 +·C7H5O3 −, the azetidine ring is virtually planar, with a mean deviation from the plane of 0.0242 Å. The dihedral angle between the two nitro groups is 87.5 (1)°

Modeling Social Media User Content Generation Using Interpretable Point Process Models

In this article, we study the activity patterns of modern social media users on platforms such as Twitter and Facebook. To characterize the complex patterns we observe in users' interactions with social media, we describe a new class of point process models. The components in the model have straightforward interpretations and can thus provide meaningful insights into user activity patterns. A composite likelihood approach and a composite EM estimation procedure are developed to overcome the challenges that arise in parameter estimation. Using the proposed method, we analyze Donald Trump's Twitter data and study if and how his tweeting behavior evolved before, during and after the presidential campaign. Additionally, we analyze a large-scale social media data from Sina Weibo and identify interesting groups of users with distinct behaviors; in this analysis, we also discuss the effect of social ties on a user's online content generating behavior

catena-Poly[[[tetra­aqua­praseo­dym­ium(III)]-di-μ-nicotinato-κ2 O:N;κ2 O:N-disilver(I)-di-μ-nicotinato-κ2 N:O;κ2 N:O] perchlorate monohydrate]

In the title compound, {[Ag2Pr(C6H4NO2)4(H2O)4]ClO4·H2O}n, the PrIII atom, lying on a twofold rotation axis, has a distorted square-anti­prismatic coordination geometry, defined by four O atoms from four nicotinate (nic) ligands and four water mol­ecules. The AgI atom is coordinated in an almost linear fashion by two pyridyl N atoms from two nicotinate ligands. The linear coordination is augmented by weak inter­actions with three O atoms from one perchlorate anion, one uncoordinated water mol­ecule and one carboxyl­ate group. Two Pr atoms link two {Ag(nic)2}+ units into a ring, which is further extended into an infinite zigzag chain by sharing the Pr atoms. These chains are further connected into a three-dimensional network via weak Ag⋯O inter­actions, O—H⋯O hydrogen bonds, Ag⋯Ag inter­actions [3.357 (2) Å] and π–π inter­actions between the pyridyl rings [centroid–centroid distance = 3.685 (4) Å]

Block transformation of hybrid cellular automata

By introducing the sequence-block transformation and vector-block transformation, a discussion of symbolic dynamics of hybrid cellular automation (HCA) and hybrid cellular automation with memory (HCAM) is presented in this paper. As the local evolution rules of HCA and HCAM are not uniform, the new uniform cellular automata (CAs) with multiple states can be constructed by specific block transformations. It is proved that the new CA rules are topologically conjugate with the originals. Furthermore, the complex dynamics of the HCA and HCAM rules can be investigated via the new CA rules

1-(2,4-Dinitro­phen­yl)-3,3-dinitro­azetidine

In the title compound, C9H7N5O8, the dihedral angle between the mean plane of the azetidine ring and that of the benzene ring is 26.1 (1)°; the planes of the two nitro groups of the azetidine ring are aligned at 88.7 (1)°

1-Benzoyl-3,3-dinitro­azetidine

In the title gem-dinitro­azetidine derivative, C10H9N3O5, the azetidine ring is almost planar, the maximum value of the endocyclic torsion angle being 0.92 (14)°. The gem-dinitro groups are mutually perpendicular and the dihedral angle between the azetidine and benzene rings is 46.70 (10)