5,329 research outputs found

    The time function of stock price

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    This paper tends to define the quantitative relationship between the stock price and time as a time function. Based on the empirical evidence that the log-return of a stock is the series of white noise, a mathematical model of the integral white noise is established to describe the phenomenon of stock price movement. A deductive approach is used to derive the auto-correlation function, displacement formula and power spectral density of the stock price movement, which reveals not only the characteristics and rules of the movement but also the predictability of the stock price. The deductive fundamental is provided for the price analysis, prediction and risk management of portfolio investment.Comment: 12 pages, 3 figure

    Phase-locked scroll waves defy turbulence induced by negative filament tension

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    Scroll waves in a three-dimensional media may develop into turbulence due to negative tension of the filament. Such negative tension-induced instability of scrollwaves has been observed in the Belousov-Zhabotinsky reaction systems. Here we propose a method to restabilize scroll wave turbulence caused by negative tension in three-dimensional chemical excitable media using a circularly polarized (rotating) external field. The stabilization mechanism is analyzed in terms of phase-locking caused by the external field, which makes the effective filament tension positive. The phase-locked scrollwaves that have positive tension and higher frequency defy the turbulence and finally restore order. A linear theory for the change of filament tension caused by a generic rotating external field is presented and its predictions closely agree with numerical simulations

    Electrochemical behavior of lansoprazole at a multiwalled carbon nanotubes-ionic liquid modified glassy carbon electrode and its electrochemical determination

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    The electrochemical behavior of lansoprazole (LNS) has been investigated at a glassy carbon electrode (GCE) and the electrode modified by a gel containing multiwalled carbon nanotubes (MWCNTs) and an room-temperature ionic liquid (RTIL) of 1-Butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) in 0.10 M phosphate buffer solution of pH 6.8. It was found that an irreversible anodic oxidation peak with Epa as 1.060 V appeared at MWCNTs-RTIL/GCE. Under the optimized experimental conditions a linear calibration curve were obtained over the concentration range from 5.0 μM to 0.20 mM by differential pulse voltammetry with the limit of detection (LOD, S/N = 3) as 0.28 μM. In addition, the novel MWCNTs-RTIL/GCE was also characterized by the electrochemical impedance spectroscopy and the proposed method has been successfully applied in the electrochemical quantitative determination of LNS content in commercial tablet samples and the determination results could meet the determination requirement

    Accuracy of lung and diaphragm ultrasound in predicting infant weaning outcomes: a systematic review and meta-analysis

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    BackgroundAlthough lung and diaphragm ultrasound are valuable tools for predicting weaning results in adults with MV, their relevance in children is debatable. The goal of this meta-analysis was to determine the predictive value of lung and diaphragm ultrasound in newborn weaning outcomes.MethodsFor eligible studies, the databases MEDLINE, Web of Science, Cochrane Library, PubMed, and Embase were thoroughly searched. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS−2) method was used to evaluate the study's quality. Results were gathered for sensitivity, specificity, diagnostic odds ratio (DOR), and the area under the curve of summary receiver operating characteristic curves (AUSROC). To investigate the causes of heterogeneity, subgroup analyses and meta-regression were conducted.ResultsA total of 11 studies were suitable for inclusion in the meta-analysis, which included 828 patients. The pooled sensitivity and specificity of lung ultrasound (LUS) were 0.88 (95%CI, 0.85–0.90) and 0.81 (95%CI, 0.75–0.87), respectively. The DOR for diaphragmatic excursion (DE) is 13.17 (95%CI, 5.65–30.71). The AUSROC for diaphragm thickening fraction (DTF) is 0.86 (95%CI, 0.82–0.89). The most sensitive and specific method is LUS. The DE and DTF were the key areas where study heterogeneity was evident.ConclusionsLung ultrasonography is an extremely accurate method for predicting weaning results in MV infants. DTF outperforms DE in terms of diaphragm ultrasound predictive power

    6-Isopropyl-3-phenyl-5-(p-tol­yloxy)-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one: whole-mol­ecule disorder

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    The title compound, C20H19N5O2, exhibits whole-mol­ecule disorder the refined ratios of the two components being 0.57 (2):0.43 (2). In the major component, the essentially planar [maximum deviation 0.033 (17) Å] fused pyrimidine and triazole ring system forms a dihedral angle of 10.5 (3)° with the phenyl ring, while in the minor component of disorder this angle is 27.5 (5)°. The crystal structure is stabilized by π–π stacking inter­actions between symmetry-related triazole and pyrimidine rings, with centroid–centroid distances of 3.594 (10) Å

    Relationship between neonatal dacryocystitis and cesarean section and the treatment of neonatal dacryocystitis

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    AIM: To explore the treatment of neonatal dacryocystitis of different ages and the relationship between caesarean section and neonatal dacryocystitis.<p>METHODS: A total of 260 cases(260 eyes)of children with neonatal dacryocystitis were divided into 1-3 months group, 4-6 months group, 7-12 months group and 13-24 months group, Each group was respectively given the lacrimal sac massage, lacrimal passage irrigation and probing of lacrimal passage method. Curative effect of each method was observed in different groups. Analysis was made to determine whether caesarean section was the cause of neonatal dacryocystitis.<p>RESULTS: The comparison between 1-3 months group and 4-6 months group showed significant difference(<i>χ</i><sup>2</sup>=19.89, <i>P</i><0.05). Lacrimal sac massage was effective for babies under 6 months, particularly in 1-3 months babies. The curative effect of lacrimal passage irrigation in four groups was compared, and there was statistical significance in the difference between the curative effect of each group(<i>χ</i><sup>2</sup>=54.95, <i>P</i><0.05). The difference between the 1-3 months group and 4-6 months group was <i>χ</i><sup>2</sup>=0.00003, <i>P</i>>0.05, lacrimal passage irrigation of these two groups showed no significant difference in efficacy. The comparison result between the other two groups showed no significant difference(<i>P</i><0.05), lacrimal passage irrigation effects are different from each group. The comparison result between 7-12 months group and 13-24 months group was <i>χ</i><sup>2</sup>=10.29, <i>P</i><0.05. Infants born by cesarean section accounted for 85% of all cases. <p>CONCLUSION:Lacrimal sac massage can exert very good therapeutic effects in infants less than 3 months. The curative effects of irrigation of lacrimal passage are quite good in babies under 12 months. Probing of lacrimal passage has a good curative effect in 7-12 months infants, but a poor curative effect in babies over 12 months. Caesarean section is an important cause for neonatal dacryocystitis
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