(S)-Ethyl 2-[4-(6-chloro­quinoxalin-2-yl­oxy)phen­oxy]propanoate

In the mol­ecule of the title compound, C19H17ClN2O4, the quinoxaline ring system is planar [maximum deviation = 0.013 (3) Å] and oriented at a dihedral angle of 80.18 (3)° with respect to the benzene ring. In the crystal structure, inter­molecular C—H⋯N inter­actions link mol­ecules into chains. π–π contacts between the quinoxaline systems [centroid–centroid distance = 3.654 (1) Å] may further stabilize the structure

Diaqua­bis(4-methyl­benzoato-κO)zinc(II)

The Zn atom in the title mononuclear complex, [Zn(C8H7O2)2(H2O)2], lies on a special position of site symmetry 2. The carboxyl­ate group binds in a monodentate manner so that the geometry is best described as tetra­hedral. Adjacent mol­ecules are linked by O—H⋯O hydrogen bonds into a three-dimensional network

Remote Sensing of Mangrove Wetlands Identification

AbstractMangrove wetland has become the important and hot object for wetland research in recent years. Because remote sensing technique has applied gradually to the survey of mangrove resources, there is important realistic and theoretical significance for the remote sensing identification research of mangrove. This paper introduces the source of data of the mangrove remote sensing recognition technology processing, classification method and feature extraction.We also analyze the existings weakness, finally we put forward some related suggestions and forecast the future

Protection of big data privacy

In recent years, big data have become a hot research topic. The increasing amount of big data also increases the chance of breaching the privacy of individuals. Since big data require high computational power and large storage, distributed systems are used. As multiple parties are involved in these systems, the risk of privacy violation is increased. There have been a number of privacy-preserving mechanisms developed for privacy protection at different stages (e.g., data generation, data storage, and data processing) of a big data life cycle. The goal of this paper is to provide a comprehensive overview of the privacy preservation mechanisms in big data and present the challenges for existing mechanisms. In particular, in this paper, we illustrate the infrastructure of big data and the state-of-the-art privacy-preserving mechanisms in each stage of the big data life cycle. Furthermore, we discuss the challenges and future research directions related to privacy preservation in big data

1-Diphenyl­phosphino-1′-(diphenyl­phosphinoyl)cobaltocenium hexa­fluorido­phosphate

The title compound, [Co(C17H14OP)(C17H14P)]PF6, was obtained unintentionally as the product of an attempted synthesis of [1,1′-bis­(oxodiphenyl­phospho­ranyl)cobaltocenium] hexa­fluorido­phosphate. The O atom of the oxo group is disordered over two positions with site occupancies of 0.65:0.35. The crystal structure contains weak inter­molecular C—H⋯F hydrogen bonds, connecting the components of the structure into chains parallel to [010]

Effect of minimally invasive percutaneous plates versus interlocking intramedullary nailing in tibial shaft treatment for fractures in adults: A meta-analysis

OBJECTIVE: The aim of this article was to determine the effects of minimally invasive percutaneous plates versus interlocking intramedullary nailing in the treatment of tibial shaft fractures in adults. METHOD: Literature searches of the Cochrane Library, PubMed, EMBASE, the Chinese Biomedical Literature database, the CNKI database, Wanfang Data, and the Weipu Journal database were performed up to August 2013. Only randomized and quasi-randomized controlled clinical trials comparing the use of percutaneous plates and interlocking intramedullary nails for tibial shaft fractures were included. Data collection and extraction, quality assessment, and data analyses were performed according to the Cochrane standards. RESULTS: Eleven trials were included. Compared with interlocking intramedullary nailing, minimally invasive percutaneous plates shortened fracture healing time and resulted in lower rates of postoperative delayed union and pain. There was no significant difference between the two methods with regard to the rates of excellent and good Johner-Wruh scoring, the rate of reoperation, and other complications. CONCLUSIONS: Overall, insufficient evidence exists regarding the effects of minimally invasive percutaneous plates versus interlocking intramedullary nailing in the treatment of tibial shaft fractures in adults. Low-quality evidence suggests that minimally invasive percutaneous plates could shorten fracture healing time, decrease the rate of postoperative delayed union, and decrease pain levels compared with interlocking intramedullary nailing. There is no significant difference between the two groups in terms of functional recovery scores, reoperation, and other complications. Further research that includes high-quality randomized controlled, multicenter trials is required to compare the effects of minimally invasive percutaneous plates versus interlocking intramedullary nailing in the treatment of tibial shaft fractures in adults

Effects of ZbZ_b states and bottom meson loops on Υ(4S)→Υ(1S,2S)π+π−\Upsilon(4S) \to \Upsilon(1S,2S) \pi^+\pi^- transitions

We study the dipion transitions $\Upsilon(4S) \rightarrow \Upsilon(nS) \pi^+\pi^-$ $(n=1,2)$. In particular, we consider the effects of the two intermediate bottomoniumlike exotic states $Z_b(10610)$ and $Z_b(10650)$ as well as bottom meson loops. The strong pion-pion final-state interactions, especially including channel coupling to $K\bar{K}$ in the $S$-wave, are taken into account model-independently by using dispersion theory. Based on a nonrelativistic effective field theory we find that the contribution from the bottom meson loops is comparable to those from the chiral contact terms and the $Z_b$-exchange terms. For the $\Upsilon(4S) \rightarrow \Upsilon(2S) \pi^+\pi^-$ decay, the result shows that including the effects of the $Z_b$-exchange and the bottom meson loops can naturally reproduce the two-hump behavior of the $\pi\pi$ mass spectra. Future angular distribution data are decisive for the identification of different production mechanisms. For the $\Upsilon(4S) \rightarrow \Upsilon(1S) \pi^+\pi^-$ decay, we show that there is a narrow dip around 1 GeV in the $\pi\pi$ invariant mass distribution, caused by the final-state interactions. The distribution is clearly different from that in similar transitions from lower $\Upsilon$ states, and needs to be verified by future data with high statistics. Also we predict the decay width and the dikaon mass distribution of the $\Upsilon(4S) \rightarrow \Upsilon(1S) K^+ K^-$ process.Comment: 25 pages, 8 figures, predictions of the decay width and the dikaon mass distribution of the $\Upsilon(4S) \rightarrow \Upsilon(1S) K^+ K^-$ process added, more discussions adde

A Mathematical Model with Pulse Effect for Three Populations of the Giant Panda and Two Kinds of Bamboo

A mathematical model for the relationship between the populations of giant pandas and two kinds of bamboo is established. We use the impulsive perturbations to take into account the effect of a sudden collapse of bamboo as a food source. We show that this system is uniformly bounded. Using the Floquet theory and comparison techniques of impulsive equations, we find conditions for the local and global stabilities of the giant panda-free periodic solution. Moreover, we obtain sufficient conditions for the system to be permanent. The results provide a theoretical basis for giant panda habitat protection