99 research outputs found

    Application of continuous wavelet transform to the analysis of the modulus of the fractional Fourier transform bands for resolving two component mixture

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    In this paper, the fractional Fourier transform (FrFT) is applied to the spectral bands of two component mixture containing oxfendazole and oxyclozanide to provide the multicomponent quantitative prediction of the related substances. With this aim in mind, the modulus of FrFT spectral bands are processed by the continuous Mexican Hat family of wavelets, being denoted by MEXH-CWT-MOFrFT. Four modulus sets are obtained for the parameter a of the FrFT going from 0.6 up to 0.9 in order to compare their effects upon the spectral and quantitative resolutions. Four linear regression plots for each substance were obtained by measuring the MEXH-CWT-MOFrFT amplitudes in the application of the MEXH family to the modulus of the FrFT. This new combined powerful tool is validated by analyzing the artificial samples of the related drugs, and it is applied to the quality control of the commercial veterinary samples

    Continuous wavelet transform methods for the simultaneous determinations and dissolution profiles of valsartan and hydrochlorothiazide in tablets

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    ABSTRACT Continuous wavelet transform (CWT) was proposed for the simultaneous determination and dissolution profiles of valsartan (VAL) and hydrochlorothiazide (HCT) in tablets, without the use of a chemical separation procedure. The CWT approach was applied to the original UV spectra and their ratio spectra in the optimal wavelength ranges. After testing several wavelet families, Mexican hat function-CWT and Daubechies7-CWT (mexh-CWT and db7-CWT, respectively) were found to be suitable for the transformation of the original UV spectra. In the following procedure, mexh-CWT and Coiflets3-CWT (coif3-CWT) were found to be appropriate for the signal analysis of ratio spectra (RS) of VAL/HCT and HCT/VAL. Calibration graphs for VAL and HCT were obtained by measuring db7-CWT and mexh-CWT amplitudes in the transformation of the original absorption spectra and RS-coif-CWT and RS-mexh-CWT amplitudes in the transformation of the ratio spectra. The validity and applicability of the proposed CWT methods were evaluated through the analysis of an independent set of synthetic binary mixtures consisting of VAL and HCT. The proposed signal processing methods were then successfully applied to the simultaneous quantitative evaluation and simultaneous dissolution profiles of the related drugs in commercial tablets, with good agreement reported for the experimental results

    Nonlinear Behaviour of Two-Whyte Stone Walls

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    Engineers work hard to convert the highly uncertain and nonlinear behavior of historic masonry structures into something that can be understood with mathematical certainty. Therefore, practical and also accurate structural analysis techniques are still needed for the preserve the historical monuments as a huge cultural heritage. In this context, determining the mechanical properties of historical walls under in-plane and out-of-plane lateral loadings is one of the most important aim. This study aims to investigate the three dimensional (3D) nonlinear behaviour of stone walls subjected to a combination of lateral and vertical loads using approprate constitutive numerical modeling. For this purpose, a simplified micro modeling approach has been proposed for the 3D nonlinear finite element analysis (NLFEA) of stone wall. The dry-stone masonry wall from the literature has been used in the verification step for the proposed model. After that, the new two-whyte stone wall has been constructed in accordance with the original material characteristics derived from the experimental studies and tested under shear compression. Finally, numerical results of NLFEA and experimental results of walls have been compared. It was observed that the numerical analysis results are well matched with the experimental ones

    Decreasing trends in cardiovascular mortality in Turkey between 1988 and 2008.

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    BACKGROUND: Cardiovascular disease (CVD) mortality increased in developed countries until the 1970s then started to decline. Turkey is about to complete its demographic transition, which may also influence mortality trends. This study evaluated trends in coronary heart disease (CHD) and stroke mortality between 1988 and 2008. METHODS: The number of deaths by cause (ICD-8), age and sex were obtained from the Turkish Statistical Institute (TurkStat) annually between 1988 and 2008. Population statistics were based on census data (1990 and 2000) and Turkstat projections. European population standardised mortality rates for CHD and stroke were calculated for men and women over 35 years old. Joinpoint Regression was used to identify the points at which a statistically significant (p < 0.05) change of the trend occurred. RESULTS: The CHD mortality rate increased by 2.9% in men and 2.0% in women annually from 1988 to 1994, then started to decline. The annual rate of decline for men was 1.7% between 1994-2008, whilst in women it was 2.8% between 1994-2000 and 6.7% between 2005-2008 (p < 0.05 for all periods).Stroke mortality declined between 1990-1994 (annual fall of 3.8% in both sexes), followed by a slight increase between 1994-2004 (0.6% in men, 1.1% in women), then a further decline until 2008 (annual reduction of 4.4% in men, 7.9% in women) (p < 0.05 for all periods). CONCLUSIONS: A decrease in CVD mortality was observed from 1995 onwards in Turkey. The causes need to be explored in detail to inform future policy priorities in noncommunicable disease control

    Political connections and corporate financial decision making

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    This paper investigates whether and how political connections influence managerial financial decisions. Our study reveals that those firms that have a politician on its board of directors are highly leveraged, use more long-term debt, hold large excess cash and are associated with low quality financial reporting compared to their non-connected counterparts. These effects escalate with the strength of the connected politician and whether he or his party is in power. The winning party effect is observed to be stronger than victory by the politician himself. Overall, our paper provides strong evidence that political connection is a two-edged sword. It is indeed a valuable resource for connected firms, but it comes at a cost of higher agency problems

    Capital Structure and Oligarch Ownership

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    This study examines the effects of oligarch ownership on corporate capital structures. Using panel data from Ukraine, I find that oligarch-owned companies employ significantly more debt and liabilities than their peers. However, there is no direct relation between oligarch ownership and target capital structure. Whereas the determinants of target leverage are similar across all owners, differences in firm characteristics also have a fairly small effect. I show that larger leverage is due to better access to debt, which results in lower rebalancing costs and faster restructurings of oligarch-owned companies. The findings clearly suggest that oligarchs benefit from the accumulated advantages

    Medication calculation skills of graduating nursing students within European context.

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    To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadAim: The aim of this study is to evaluate the medication calculation skills of graduating nursing students in six European countries and analyse the associated factors. Background: Medication calculation skills are fundamental to medication safety, which is a substantial part of patient safety. Previous studies have raised concerns about the medication calculation skills of nurses and nursing students. Design: As part of a broader research project, this study applies a multinational cross-sectional survey design with three populations: graduating nursing students, nurse managers and patients. Methods: The students performed two calculations (tablet and fluid) testing medication calculation skills requiring different levels of conceptual understanding and arithmetic. The managers and patients answered one question about the students' medication kills. In total, 1,796 students, 538 managers and 1,327 patients participated the study. The data were analysed statistically. The STROBE guideline for cross-sectional studies was applied. Results: Almost all (99%) of the students performed the tablet calculation correctly, and the majority (71%) answered the fluid calculation correctly. Older age, a previous degree in health care and satisfaction with their current degree programme was positively associated with correct fluid calculations. The patients evaluated the students' medication skills higher than the nurse managers did and the evaluations were not systematically aligned with the calculation skills tested. Conclusions: Nursing students have the skills to perform simple medication calculations, but a significant number of students have difficulties with calculations involving multiple operations and a higher level of conceptual understanding. Due to the variation in students' medication calculation skills and the unalignment between the managers' and patients' evaluations and the calculation tests, further research is needed. Relevance to clinical practice: Graduating nursing students enter clinical field as qualified professionals, but there is still room for improvement in their medication calculation skills. This calls for attention in the fields of clinical nursing, education and research. Keywords: drug dosage calculations; graduating nursing students; medication calculation skills; nurse managers; patients.Academy of Finland European Commissio
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