1,756 research outputs found

    State Observer Synchronization Used in the Three-Dimensional Duffing System

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    Synchronization of chaotic systems has attracted extensive concern in the past few years. In this study, we investigate a new structure of Duffing system by the variable decomposition method. Then, we analyze the state observer synchronization based on the new Duffing system. It is proved theoretically that the designed observer can keep synchronization with Duffing chaotic system in transmitter. The design is presented reasonably with the conditional Lyapunov exponents, and its effectiveness is clearly shown in simulation results

    Dynamics of quantum entanglement in the reservoir with memory effects

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    The non-Markovian dynamics of quantum entanglement is studied by the Shabani-Lidar master equation when one of entangled quantum systems is coupled to a local reservoir with memory effects. The completely positive reduced dynamical map can be constructed in the Kraus representation. Quantum entanglement decays more slowly in the non-Markovian environment. The decoherence time for quantum entanglement can be markedly increased by the change of the memory kernel. It is found out that the entanglement sudden death between quantum systems and entanglement sudden birth between the system and reservoir occur at different instants.Comment: 14 pages, 3 figure

    Diagnosis, treatment and follow-up of 25 patients with melamine-induced kidney stones complicated by acute obstructive renal failure in Beijing Children’s Hospital

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    A total of 25 Chinese patients aged 6 to 36 months hospitalised at Beijing Children’s Hospital due to melamine-induced kidney stones complicated by acute obstructive renal failure in 2008 were included in a study in order to diagnose and treat these special cases more effectively. Feeding history, clinical presentation, ultrasound findings, treatments and effects were summarised. Twelve to seventeen months follow-up was reported also. Ultrasound examination showed that calculi were located at the kidney and ureters. Stones were composed of both uric acid and melamine in a molar ratio of 1.2:1 to 2.1:1. Treatments providing liquid plus alkalisation of urine proved to be effective in helping the patients pass the stones. Surgical intervention was needed in severe cases. Renal function returned to normal in all 25 patients after various durations of therapy. Sixty-eight percent of the patients expelled all of the calculi within 3 months, 90% in 6 months and 95% in 9 months, without sequelae till now. Melamine-contaminated milk formula can cause kidney stones in infants, which should be diagnosed by feeding history, clinical symptoms and ultrasound examination. Composition of the stones was not only of melamine but also uric acid. Providing liquid orally or intravenously plus alkalisation of urine proved to promote the removal of the stones. Follow-up of 12 to 17 months after discharge showed no sequelae

    The LAMOST Survey of Background Quasars in the Vicinity of the Andromeda and Triangulum Galaxies -- II. Results from the Commissioning Observations and the Pilot Surveys

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    We present new quasars discovered in the vicinity of the Andromeda and Triangulum galaxies with the LAMOST during the 2010 and 2011 observational seasons. Quasar candidates are selected based on the available SDSS, KPNO 4 m telescope, XSTPS optical, and WISE near infrared photometric data. We present 509 new quasars discovered in a stripe of ~135 sq. deg from M31 to M33 along the Giant Stellar Stream in the 2011 pilot survey datasets, and also 17 new quasars discovered in an area of ~100 sq. deg that covers the central region and the southeastern halo of M31 in the 2010 commissioning datasets. These 526 new quasars have i magnitudes ranging from 15.5 to 20.0, redshifts from 0.1 to 3.2. They represent a significant increase of the number of identified quasars in the vicinity of M31 and M33. There are now 26, 62 and 139 known quasars in this region of the sky with i magnitudes brighter than 17.0, 17.5 and 18.0 respectively, of which 5, 20 and 75 are newly-discovered. These bright quasars provide an invaluable collection with which to probe the kinematics and chemistry of the ISM/IGM in the Local Group of galaxies. A total of 93 quasars are now known with locations within 2.5 deg of M31, of which 73 are newly discovered. Tens of quasars are now known to be located behind the Giant Stellar Stream, and hundreds behind the extended halo and its associated substructures of M31. The much enlarged sample of known quasars in the vicinity of M31 and M33 can potentially be utilized to construct a perfect astrometric reference frame to measure the minute PMs of M31 and M33, along with the PMs of substructures associated with the Local Group of galaxies. Those PMs are some of the most fundamental properties of the Local Group.Comment: 26 pages, 6 figures, AJ accepte

    An improved method for predicting truncated multiple recursive generators with unknown parameters

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    Multiple recursive generators are an important class of pseudorandom number generators which are widely used in cryptography. The predictability of truncated sequences that predict the whole sequences by the truncated high-order bits of the sequences is not only a crucial aspect of evaluating the security of pseudorandom number generators but also serves an important role in the design of pseudorandom number generators. This paper improves the work of Sun et al on the predictability of truncated multiple recursive generators with unknown parameters. Given a few truncated digits of high-order bits output by a multiple recursive generator, we adopt the resultant, the Chinese Remainder Theorem and the idea of recovering pp-adic coordinates of the coefficients layer by layer, and Kannan\u27s embedding technique to recover the modulus, the coefficients and the initial state, respectively. Experimental results show that our new method is superior to that of the work of Sun et al, no matter in terms of the running time or the number of truncated digits required

    In situ dynamic tracking of heterogeneous nanocatalytic processes by shell-isolated nanoparticle-enhanced Raman spectroscopy

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    原位监测纳米催化反应过程对深入认识反应机理、设计高效催化剂具有重要意义。作为一种具有超高灵敏度的表面分析技术,表面增强拉曼光谱(SERS)是可提供反应过程中催化剂表面吸附物种的丰富信息。然而,仅有Au、Ag、Cu等少数金属在形成特定纳米结构时才能提供较强的拉曼增强,且它们会对催化剂的性质及反应过程产生严重干扰。这就极大地限制了SERS在实际多相催化体系中的应用。鉴于此,该论文发展了一种利用壳层隔绝纳米粒子增强拉曼光谱原位监测纳米催化过程的方法。通过将纳米催化剂组装于壳层隔绝纳米粒子表面,形成SHIENRS卫星结构,利用内核Au纳米粒子增强催化剂表面的拉曼信号,SiO2壳层隔绝Au对催化剂及反应的影响,从而直接获得了纳米催化剂表面物种的真实信息。利用这种SHINERS卫星策略,他们实现了CO氧化反应的原位监测,直接观测到了反应条件下催化剂表面吸附物种。并结合DFT计算,对反应机理进行了阐述。该研究表明SHINERS卫星策略可作为原位跟踪催化反应过程的有效方法,为纳米催化的原位研究提供了一种新的思路。 同时,我校也将在今年12月5-9日举办表面增强拉曼光谱国际会议(International Conference on SERS),讨论SERS领域的最新进展。会议期间,SERS领域的先驱与权威Richard P. Van Duyne、Martin Moskovits、Andreas Otto以及相关学科的顶级学者Peter G. Bruce、Stefan A. Maier等将作大会报告(会议官方网站http://sers2017.xmu.edu.cn/)。【Abstract】Surface molecular information acquired in situ from a catalytic process can greatly promote the rational design of highly efficient catalysts by revealing structure-activity relationships and reaction mechanisms. Raman spectroscopy can provide this rich structural information, but normal Raman is not sensitive enough to detect trace active species adsorbed on the surface of catalysts. Here we develop a general method for in situ monitoring of heterogeneous catalytic processes through shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) satellite nanocomposites (Au-core silica-shell nanocatalyst-satellite structures), which are stable and have extremely high surface Raman sensitivity. By combining operando SHINERS with density functional theory calculations, we identify the working mechanisms for CO oxidation over PtFe and Pd nanocatalysts, which are typical low- and high-temperature catalysts, respectively. Active species, such as surface oxides, superoxide/peroxide species and Pd–C/Pt–C bonds are directly observed during the reactions. We demonstrate that in situ SHINERS can provide a deep understanding of the fundamental concepts of catalysis.This work was supported by the NSFC (21522508, 21427813, 21373167, 21521004, 21573178 and 21673187), Natural Science Foundation of Guangdong Province (2016A030308012), the Fundamental Research Funds for the Central Universities (20720150039 and 20720160046), ‘111’Project (B16029), and the Thousand Youth Talents Plan of China。 研究工作得到国家自然科学基金优秀青年基金、谱学分析创新研究群体和青年千人计划等资助

    Apolipoprotein B is associated with metabolic syndrome in Chinese families with familial combined hyperlipidemia, familial hypertriglyceridemia and familial hypercholesterolemia

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    Abstract There is a paucity of data concerning the metabolic syndrome (MetS) in families with familial combined hyperlipidemia (FCHL), familial hypertriglyceridemia (FHTG), familial hypercholesterolemia (FH) and normolipidemic families in China. This study investigated the prevalence of MetS in these families and explored potential factors relevant to MetS. We recruited 70 families with 560 individuals ≥ 20 years of age, including 43 FCHL families with 379 individuals, 3 FHTG families with 30 individuals, 16 FH families with 102 individuals and 8 normolipidemic families with 49 individuals. The definition of MetS is determined using modified criteria of National Cholesterol Education Program substituting body mass index for waist circumference. MetS is identified in 60.7% of FCHL patients and 71.4% of FHTG patients. The prevalence of MetS in family members is 36.7% for FCHL, 33.3% for FHTG, 17.6% for FH and 16.3% for normolipidemic families, with an odds ratio (OR) of 2.97 (95% CI 1.29-7.07, P = 0.007) in FCHL families compared with normolipidemic families. Apolipoprotein B (apoB) is associated with MetS by multiple logistic analysis with an OR of 1.05 (1.03-1.07, P < 0.001) in FCHL families, OR of 1.26 (1.03-1.55, P = 0.026) in FHTG and OR of 1.07 (1.01-1.12, P = 0.014) in FH families, independent of variables including age, gender, apolipoprotein A1, and low density lipoprotein cholesterol. Apolipoprotein A1 provided an OR of 0.95 (0.94-0.97, P < 0.001) in FCHL families and OR of 0.94 (0.90-0.97, P = 0.011) in FH families, but neither in FHTG nor in normolipidemic families (both P > 0.05). Thus, apoB may be regarded as a relevant factor in the assessment of MetS in FCHL, FHTG and FH families. However, this finding needs to be verified by prospective studies in diverse ethnicities and warrants additional studies to elucidate possible mechanisms linking apoB to MetS

    A comprehensive genome variation map of melon identifies multiple domestication events and loci influencing agronomic traits

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    Melon is an economically important fruit crop that has been cultivated for thousands of years; however, the genetic basis and history of its domestication still remain largely unknown. Here we report a comprehensive map of the genomic variation in melon derived from the resequencing of 1,175 accessions, which represent the global diversity of the species. Our results suggest that three independent domestication events occurred in melon, two in India and one in Africa. We detected two independent sets of domestication sweeps, resulting in diverse characteristics of the two subspecies melo and agrestis during melon breeding. Genome-wide association studies for 16 agronomic traits identified 208 loci significantly associated with fruit mass, quality and morphological characters. This study sheds light on the domestication history of melon and provides a valuable resource for genomics-assisted breeding of this important crop.info:eu-repo/semantics/acceptedVersio
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