1-Isopropyl-4-tosyl­piperazin-1-ium trifluoro­acetate

In the title compound, C14H23N2O2S+·C2F3O2 −, the piperazine ring adopts a chair conformation. The crystal packing is stabilized by C—H⋯O and N—H⋯O hydrogen bonds between the cation and anion. The F atoms are disordered over two positions; the site occupancy factors are 0.55 (2) and 0.45 (2)

Expectation-Maximizing Network Reconstruction and MostApplicable Network Types Based on Binary Time Series Data

Based on the binary time series data of social infection dynamics, we propose a general framework to reconstruct 2-simplex complexes with two-body and three-body interactions by combining the maximum likelihood estimation in statistical inference and introducing the expectation maximization. In order to improve the code running efficiency, the whole algorithm adopts vectorization expression. Through the inference of maximum likelihood estimation, the vectorization expression of the edge existence probability can be obtained, and through the probability matrix, the adjacency matrix of the network can be estimated. We apply a two-step scheme to improve the effectiveness of network reconstruction while reducing the amount of computation significantly. The framework has been tested on different types of complex networks. Among them, four kinds of networks can obtain high reconstruction effectiveness. Besides, we study the influence of noise data or random interference and prove the robustness of the framework, then the effects of two kinds of hyper-parameters on the experimental results are tested. Finally, we analyze which type of network is more suitable for this framework, and propose methods to improve the effectiveness of the experimental results

Observational evidence for a spin-up line in the P-Pdot diagram of millisecond pulsars

It is believed that millisecond pulsars attain their fast spins by accreting matter and angular momentum from companion stars. Theoretical modelling of the accretion process suggests a spin-up line in the period-period derivative ($P$-$\dot{P}$) diagram of millisecond pulsars, which plays an important role in population studies of radio millisecond pulsars and accreting neutron stars in X-ray binaries. Here we present observational evidence for such a spin-up line using a sample of 143 radio pulsars with $P$ < 30 ms. We also find that PSRs~J1823$-$3021A and J1824$-$2452A, located near the classic spin-up line, are consistent with the broad population of millisecond pulsars. Finally, we show that our approach of Bayesian inference can probe accretion physics, allowing constraints to be placed on the accretion rate and the disk-magnetosphere interaction.Comment: 10 pages, 4 figures, 2 tables. Accepted for publication by ApJ

(Piperazin-1-ium-κN 4)tris­(thio­cyanato-κN)zinc(II)

Hydro­thermal reaction of NaSCN, piperazine, ZnII and 2,6-naphthalenedicarboxylic acid in aqueous solutions gave rise to the title complex, [Zn(NCS)3(C4H11N2)]. The ZnII atom is four-coordinate with distorted tetra­hedral geometry and lies in a mirror plane. N—H⋯S hydrogen bonds assemble the mol­ecules to form a three-dimensional framework

Scaling and memory in the return intervals of energy dissipation rate in three-dimensional fully developed turbulence

We study the statistical properties of return intervals $r$ between successive energy dissipation rates above a certain threshold $Q$ in three-dimensional fully developed turbulence. We find that the distribution function $P_Q(r)$ scales with the mean return interval $R_Q$ as $P_Q(r)=R_Q^{-1}f(r/R_Q)$ except for $r=1$, where the scaling function $f(x)$ has two power-law regimes. The return intervals are short-term and long-term correlated and possess multifractal nature. The Hurst index of the return intervals decays exponentially against $R_Q$, predicting that rare extreme events with $R_Q\to\infty$ are also long-term correlated with the Hurst index $H_\infty=0.639$.Comment: 5 pages, 5 figure