1,638 research outputs found

    A local version of the Pawlucki-Plesniak extension operator

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    Cataloged from PDF version of article.Using local interpolation of Whitney functions, we generalize the Pawłucki and Pleśniak approach to construct a continuous linear extension operator. We show the continuity of the modified operator in the case of generalized Cantor-type sets without Markov's Property. © 2004 Elsevier Inc. All rights reserved

    Dielectronic Recombination of Fe XV forming Fe XIV: Laboratory Measurements and Theoretical Calculations

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    We have measured resonance strengths and energies for dielectronic recombination (DR) of Mg-like Fe XV forming Al-like Fe XIV via N=3 -> N' = 3 core excitations in the electron-ion collision energy range 0-45 eV. All measurements were carried out using the heavy-ion Test Storage Ring at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We have also carried out new multiconfiguration Breit-Pauli (MCBP) calculations using the AUTOSTRUCTURE code. For electron-ion collision energies < 25 eV we find poor agreement between our experimental and theoretical resonance energies and strengths. From 25 to 42 eV we find good agreement between the two for resonance energies. But in this energy range the theoretical resonance strengths are ~ 31% larger than the experimental results. This is larger than our estimated total experimental uncertainty in this energy range of +/- 26% (at a 90% confidence level). Above 42 eV the difference in the shape between the calculated and measured 3s3p(^1P_1)nl DR series limit we attribute partly to the nl dependence of the detection probabilities of high Rydberg states in the experiment. We have used our measurements, supplemented by our AUTOSTRUCTURE calculations, to produce a Maxwellian-averaged 3 -> 3 DR rate coefficient for Fe XV forming Fe XIV. The resulting rate coefficient is estimated to be accurate to better than +/- 29% (at a 90% confidence level) for k_BT_e > 1 eV. At temperatures of k_BT_e ~ 2.5-15 eV, where Fe XV is predicted to form in photoionized plasmas, significant discrepancies are found between our experimentally-derived rate coefficient and previously published theoretical results. Our new MCBP plasma rate coefficient is 19-28% smaller than our experimental results over this temperature range

    The effect of solvent and pressure on polycaprolactone solutions for particle and fibre formation

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    Polycaprolactone (PCL) is a widely used material in many applications to tackle health problems worldwide. Formed micro- or nanosized PCL particles and fibres benefit from a higher surface area to volume ratio and are valuable in those applications, thus there is always a push to achieve smaller diameters. Electrohydrodynamic (EHD) technologies have been at the forefront in the production of polymeric biomaterials, and pressurised gyration (PG) has also enhanced possibilities by its ability to spin comparable fibres at rapid speeds. In this work, PCL microparticles and fibres were separately produced by changing key operating parameters of EHD and PG systems and PCL solution properties. Initially, PCL microparticles were formed by electrospraying with different binary solvent systems, followed by pressurised gyration fibre production with various singular solvents and a pre-optimised binary solvent system. As anticipated, the use of binary systems altered particle morphologies and diameters, while increased pressure and the use of different solvents greatly affected the characteristics of resulting fibres. The morphology of PCL was found to be highly dependent on the solvents and operating parameters of the technology used

    Mental health and human trafficking: responding to survivors' needs.

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    Mental health professionals have opportunities to intervene and provide care for trafficked people. Research shows that mental health problems - including depression, anxiety and post-traumatic stress disorder - are prevalent among trafficked people, and that at least some trafficked people come into contact with secondary mental health services in England

    The hjorth's IDB generator of distributions: properties, characterizations, regression modeling and applications

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    We introduce a new flexible class of continuous distributions via the Hjorth’s IDB model. We provide some mathematical prop-erties of the new family. Characterizations based on two truncated moments, conditional expectation as well as in terms of thehazard function are presented. The maximum likelihood method is used for estimating the model parameters. We assess the per-formance of the maximum likelihood estimators in terms of biases and mean squared errors by means of the simulation study.A new regression model as well as residual analysis are presented. Finally, the usefulness of the family is illustrated by means offour real data sets. The new model provides consistently better fits than other competitive models for these data sets

    The Odd Power Lindley Generator of Probability Distributions: Properties, Characterizations and Regression Modeling

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    In this study, a new flexible family of distributions is proposed with its statistical properties as well as some useful characterizations. The maximum likelihood method is used to estimate the unknown model parameters by means of two simulation studies. A new regression model is proposed based on a special member of the proposed family called, the log odd power Lindley Weibull distribution. Residual analysis is conducted to evaluate the model assumptions. Four applications to real data sets are given to demonstrate the usefulness of the proposed model

    Determinación de algunos metales inorgánicos en aceites vegetales comestibles mediante espectroscopia de emisión atómicacon fuente de plasma acoplado inductivamente (ICP-AES)

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    Seventeen edible vegetable oils were analyzed spectrometrically for their metal (Cu, Fe, Mn, Co, Cr, Pb, Cd, Ni, and Zn) contents. Toxic metals in edible vegetable oils were determined by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The highest metal concentrations were measured as 0.0850, 0.0352, 0.0220, 0.0040, 0.0010, 0.0074, 0.0045, 0.0254 and 0.2870 mg/kg for copper in almond oil, for iron in corn oil-(c), for manganese in soybean oil, for cobalt in sunflower oil-(b) and almond oil, for chromium in almond oil, for lead in virgin olive oil, for cadmium in sunflower oil-(e), for nickel almond oil and for zinc in almond oil respectively. The method for determining toxic metals in edible vegetable oils by using ICP-AES is discussed. The metals were extracted from low quantities of oil (2-3 g) with a 10% nitric acid solution. The extracted metal in acid solution can be injected into the ICPAES. The proposed method is simple and allows the metals to be determined in edible vegetable oils with a precision estimated below 10% relative standard deviation (RSD) for Cu, 5% for Fe, 15% for Mn, 8% for Co, 10% for Cr, 20% for Pb, 5% for Cd, 16% for Ni and 11% for Zn.En este estudio se analizó espectrométricamente el contenido en metales (Cu, Fe, Mn, Co, Cr, Pb, Cd, Ni, and Zn) de 17 aceites vegetales comestibles mediante ICP-AES. Las concentaciones más elevadas se encontraron para el cobre en el aceite de almendra (0.0850 mg/kg), para el hierro en el aceite de maiz(c),(0.0352 mg/kg), para el manganeso en el aceite de soja (0.0220 mg/kg), para el cobalto en el aceite de girasol (b) (0.0040 mg/kg), para el cromo en el aceite de almendra (0.0010 mg/kg), para el plomo en el aceite de oliva virgen (0.0074 mg/kg), para el cadmio en el aceite de girasol (e) (0.0045 mg/kg), para el niquel en el aceite de almendra (0.0254 mg/kg) y para el zincen el aceite de almendra (0.2870 mg/kg). Los metales se extrajeron a partir de bajas cantidades de aceite (2-3 g), con una solución de ácido nítrico al 10%. Se discute el método y se conclluye que el método propuesto es simple y permite la determinación en aceites vegetales comestibles con una precisión estimada inferior al 10% para Cu, 5% para Fe, 15% para Mn. 8% para Co, 20% para Pb, 5% para Cd, 16% para Ni y 11% para Zn

    The extended gamma distribution with regression model and applications

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    This paper introduces a new extension of the gamma distribution, named as a new extended gamma distribution, via mixture representation of xgamma and gamma distributions. The statistical properties of the proposed distribution are derived such as moment generating and characteristic functions, variance, skewness, and kurtosis measures, Lorenz curve, and mean residual life function. The maximum likelihood, parametric bootstrap, method of moments, least squares, and weighted least squares estimation methods are considered to obtain the unknown model parameters. The finite sample performance of estimation methods is discussed via a simulation study. Using the proposed distribution, we propose a new regression model for the right-skewed response variable as an alternative to the gamma regression model. Two real data sets are analyzed to convince the readers for the usefulness of the proposed model
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