1-(2-Hy­droxy­benzo­yl)thio­semicarbazide hemihydrate

The asymmetric unit of the title compound, C8H9N3O2S·0.5H2O, contains two thiosemicarbazide mol­ecules with the short distance of 3.521 (3) Å between the centroids of the benzene rings, and one water mol­ecule. In the two independent mol­ecules, the benzene rings and the thio­semicarbazone fragments are twisted at 9.2 (3) and 18.5 (3)°. An extensive three-dimensional hydrogen-bonding network, formed by inter­molecular N—H⋯O, N—H⋯S and O—H⋯O hydrogen bonds, consolidates the crystal packing

Recovery of the orbital parameters and pulse evolution of V0332+53 during a huge outburst

The high mass X-ray binary (HMXB) V0332+53 became active at the end of 2004 and the outburst was observed at hard X-rays by RXTE and INTEGRAL. Based on these hard X-ray observations, the orbital parameters are measured through fitting the Doppler-shifted spin periods. The derived orbital period and eccentricity are consistent with those of Stella et al. (1985) obtained from EXOSAT observations, whereas the projected semimajor axis and the periastron longitude are found to have changed from 48$\pm$4 to 86$^{+6}_{-10}$ lt-s and from 313$^{\circ}$$\pm$10 to 283$^{\circ}$$\pm$14, respectively. This would indicate an angular speed of $\geq$ 1.5$^{\circ}$$\pm$0.8 yr$^{-1}$ for rotation of the orbit over the past 21 years. The periastron passage time of MJD 53367$\pm$1 is just around the time when the intensity reached maximum and an orbital period earlier is the time when the outburst started. This correlation resembles the behavior of a Type I outburst. During outburst the source spun up with a rate of 8.01$^{+1.00}_{-1.14}$$\times10^{-6}$ s day$^{-1}$. The evolution of pulse profile is highly intensity dependent. The separation of double pulses remained almost constant ($\sim$ 0.47) when the source was bright, and dropped to 0.37 within $\leq$ 3 days as the source became weaker. The pulse evolution of V0332+53 may correlate to the change in dominance of the emission between fan-beam and pencil-beam mechanisms.Comment: 13 pages, 3 figures, accepted for publication in ApJ

Communication-Efficient Topologies for Decentralized Learning with O(1)O(1) Consensus Rate

Decentralized optimization is an emerging paradigm in distributed learning in which agents achieve network-wide solutions by peer-to-peer communication without the central server. Since communication tends to be slower than computation, when each agent communicates with only a few neighboring agents per iteration, they can complete iterations faster than with more agents or a central server. However, the total number of iterations to reach a network-wide solution is affected by the speed at which the agents' information is ``mixed'' by communication. We found that popular communication topologies either have large maximum degrees (such as stars and complete graphs) or are ineffective at mixing information (such as rings and grids). To address this problem, we propose a new family of topologies, EquiTopo, which has an (almost) constant degree and a network-size-independent consensus rate that is used to measure the mixing efficiency. In the proposed family, EquiStatic has a degree of $\Theta(\ln(n))$, where $n$ is the network size, and a series of time-dependent one-peer topologies, EquiDyn, has a constant degree of 1. We generate EquiDyn through a certain random sampling procedure. Both of them achieve an $n$-independent consensus rate. We apply them to decentralized SGD and decentralized gradient tracking and obtain faster communication and better convergence, theoretically and empirically. Our code is implemented through BlueFog and available at \url{https://github.com/kexinjinnn/EquiTopo}Comment: NeurIPS 202