407 research outputs found

    Latest data constraint of some parameterized dark energy models

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    Using various latest cosmological datasets including Type-Ia supernovae, cosmic microwave background radiation, baryon acoustic oscillations, and estimations of the Hubble parameter, we test some dark energy models with parameterized equations of state and try to distinguish or select observation-preferred models. We obtain the best fitting results of the six models and calculate their values of the Akaike Information Criteria and Bayes Information Criterion. And we can distinguish these dark energy models from each other by using these two information criterions. However, the Λ\Lambda CDM model remains the best fit model. Furthermore, we perform geometric diagnostics including statefinder and Om diagnostics to understand the geometric behaviour of the dark energy models. We find that the six DE models can be distinguished from each other and from Λ\LambdaCDM, Chaplygin gas, quintessence models after the statefinder and Om diagnostics were performed. Finally, we consider the growth factor of the dark energy models with comparison to Λ\Lambda CDM model. Still, we find the models can be distinguished from each other and from Λ\Lambda CDM model through the growth factor approximation.Comment: 23 pages, 6 figures, to be published in CP

    Two-photon interference with two independent pseudo-thermal sources

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    The nature of two-photon interference is a subject that has aroused renewed interest in recent years and is still under debate. In this paper we report the first observation of two-photon interference with independent pseudo-thermal sources in which sub-wavelength interference is observed. The phenomenon may be described in terms of the classical statistical distribution of the two sources and their optical transfer functions.Comment: Phys. Rev. A 74, 053807 (2006

    Correlated two-photon imaging with true thermal light

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    We report the first experimental demonstration of two-photon correlated imaging with true thermal light from a hollow cathode lamp. The coherence time of the source is much shorter than that of previous experiments using random scattered light from a laser. A two-pinhole mask was used as object, and the corresponding thin lens equation was well satisfied. Since thermal light sources are easier to obtain and measure than entangled light it is conceivable that they may be used in special imaging applications.Comment: 3 pages, 5 figures, accepted by Optics Letter

    Casimir Pistons for Massive Scalar Fields

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    The Casimir force on two-dimensional pistons for massive scalar fields with both Dirichlet and hybrid boundary conditions is computed. The physical result is obtained by making use of generalized ζ\zeta-function regularization technique. The influence of the mass and the position of the piston in the force is studied graphically. The Casimir force for massive scalar field is compared to that for massless scalar field.Comment: 6 pages, 7 figures, in press version of Mod. Phys. Lett.

    Two-photon interference with true thermal light

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    Two-photon interference and "ghost" imaging with entangled light have attracted much attention since the last century because of the novel features such as non-locality and sub-wavelength effect. Recently, it has been found that pseudo-thermal light can mimic certain effects of entangled light. We report here the first observation of two-photon interference with true thermal light.Comment: 4 pages, 5 figures, PRA72, 043805 (2005

    Clinical features and treatment of pediatric patients with drug-induced anaphylaxis: a study based on pharmacovigilance data

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    We assessed the clinical features and treatment of pediatric patients with drug-induced anaphylaxis in clinical settings. Pediatric drug-induced anaphylaxis cases collected by the Beijing Pharmacovigilance Database from 2004 to 2014 were analyzed. A total of 91 cases were identified. Drug-induced anaphylaxis was primarily caused by antibiotics (53%). Children of 0-5 years were more likely to develop cyanosis symptoms than children of 13-17 years (OR = 5.14, 95%CI [1.74, 15.20], P = 0.002). Children of 13-17 years were more likely to develop hypotension than children of 6-12 years (OR = 11.79, 95%CI [2.28, 60.87], P = 0.002), and to manifest both neurological symptoms (OR = 3.56, 95%CI [1.26, 10.08], P = 0.015) and severe anaphylaxis than children of 0-5 years (OR = 15.46, 95%CI [1.85, 129.33], P = 0.002). Supratherapeutic doses of epinephrine were more likely with intravenous (IV) bolus (92%) in contrast to either intramuscular (IM) (36%, OR = 19.25, 95%CI [1.77, 209.55], P = 0.009) or subcutaneous (SC) injections (36%, OR = 19.80, 95% CI [1.94, 201.63], P = 0.005). Only 62 (68%) patients received epinephrine treatment as the first-line therapy. CONCLUSION: This study demonstrates that antibiotics were the most common cause of pediatric drug-induced anaphylaxis. Children may present with different anaphylactic signs/symptoms based on age groups. Epinephrine is under-utilized and provider education on the proper management of drug-induced anaphylaxis is warranted. What is Known: • The most common causes of anaphylaxis in children are allergies to foods. Drugs are the second most common cause of pediatric anaphylaxis. • IM epinephrine is the recommended initial treatment of anaphylaxis. What is New: • Drug-induced anaphylaxis in pediatric patients has age-related clinical features. • IV bolus epinephrine was overused and associated with supratherapeutic dosing

    Clinical and Prognostic Value of PET/CT Imaging with Combination of 68

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    Background. To evaluate the clinical and prognostic value of PET/CT with combination of 68Ga-DOTATATE and 18F-FDG in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). Method. 83 patients of GEP-NENs who underwent 68Ga-DOTATATE and 18F-FDG PET/CT were enrolled between June 2013 and December 2016. Well-differentiated (WD) NETs are divided into group A (Ki-67 < 10%) and group B (Ki-67 ≥ 10%), and poorly differentiated (PD) NECs are defined as group C. The relationship between PET/CT results and clinicopathological characteristics was retrospectively investigated. Result. For groups A/B/C, the sensitivities of 68Ga-DOTATATE and 18F-FDG were 78.8%/83.3%/37.5% and 52.0%/72.2%/100.0%. A negative correlation between Ki-67 and SUVmax of 68Ga-DOTATATE (R = −0.415; P ≤ 0.001) was observed, while a positive correlation was noted between Ki-67 and SUVmax of 18F-FDG (R = 0.683; P ≤ 0.001). 62.5% (5/8) of patients showed significantly more lesions in the bone if 68Ga-DOTATATE was used, and 22.7% (5/22) of patients showed more lymph node metastases if 18F-FDG was used. Conclusions. The sensitivity of dual tracers was correlated with cell differentiation, and a correlation between Ki-67 and both SUVmax of PET-CTs could be observed. 68Ga-DOTATATE is suggested for WD-NET and 18F-FDG is probably suitable for patients with Ki-67 ≥ 10%

    Detection and Analysis of Blood Dexmedetomidine in Drug-Facilitated Cases

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    Objective To establish a simple and rapid qualitative and quantitative detection method of dexmedetomidine in blood. Methods Blood was separated on the Allure PFP Propyl liquid chromatography column with isocratic elution after it was precipitated by acetonitrile and filtered. Qualitative and quantitative analysis of dexmedetomidine was performed using positive ion scan mode and multi-reaction monitoring mode. Results The limit of detection of dexmedetomidine in blood was 0.2 ng/mL and the limit of quantification was 0.5 ng/mL. The linearity of the method was good in the range of 0.5-1 000 ng/mL, and the correlation coefficient was greater than 0.99. The accuracy of the method was 90.34%-112.67% and the extraction recovery was 50.05%-91.08%, with no significant matrix effect. Conclusion This method is simple, selective and suitable for the qualitative and quantitative analysis of dexmedetomidine in blood, which can provide a reference for drug-facilitated cases involving dexmedetomidine
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