An Iterative Procedure for the Estimation of Drift and Diffusion Coefficients of Langevin Processes

A general method is proposed which allows one to estimate drift and diffusion coefficients of a stochastic process governed by a Langevin equation. It extends a previously devised approach [R. Friedrich et al., Physics Letters A 271, 217 (2000)], which requires sufficiently high sampling rates. The analysis is based on an iterative procedure minimizing the Kullback-Leibler distance between measured and estimated two time joint probability distributions of the process.Comment: 4 pages, 5 figure

Intention to donate via social network sites (SNSs): A comparison study between Malaysian and South Korean users

Purpose: The purpose of this paper is to explore the differences in the external factors influencing intention to donate via social network sites (SNSs), and the online donation knowledge and awareness effect on the willingness to donate via SNS in the future between Malaysian and South Korean users. Design/methodology/approach: In total, 288 samples’ data obtained from online survey using the snowball technique were analyzed through using cross-tabulation with χ2 tests and multiple regression analysis. Findings: The results show that there is no significant difference between those countries regarding the online donation knowledge and awareness. However, the online donation knowledge and awareness significantly affect the willingness to donate via SNSs for South Korean, but not for Malaysian. As for Malaysian, the results reveal that only SNS features factor does significantly influence the attitude toward online donations. As for South Korean, the charity project and internet technology features factor significantly influence the attitude toward online donations. The attitude toward online donations of both countries influences on their intention to donate via SNS. Research limitations/implications: The sample was gathered from certain regions in Malaysia and South Korea, and had slightly unbalanced characteristics (i.e. age), limiting the generalizability to the general population of both countries. Practical implications: The findings suggest that non-profit organizations should consider the culture context in planning their future SNS donation program and focus on how to deal with the internet issues (e.g. trust, security), SNS features and charity project. As for Malaysian, promoting the internet and online donation awareness should be the priority before engaging in SNS donation program. Originality/value: Whilst research on culture context in donation area is plentiful, the area of SNS donation remains underexplored. This paper offers an in-depth understanding of what influences SNS donation related to the identified culture context

Synthesis and Characterization of Some New Morpholine Derivatives

In this paper a new series of morpholine derivatives was prepared by reacting the morpholine with ethyl chloro acetate in the presence triethylamine as a catalyst in benzene gave morpholin-N-ethyl acetate(1) which reacted with hydrazine hydrate in ethanol, and gave morpholin-N-ethyl acetohydrazide (2) . Morpholin-N-aceto semithiocarbazide (3) were prepared by reacting compound(2) with ammonium thiocyanate , concentrated hydrochloric acid and ethanol as a solvent .Compound (3) reacted with sodium hydroxide and hydrochloric acid to give 5-(morpholin-N-methylene)-1H-1,2,4-triazole-3-thiol (4) .The new series of 1,2,4-triazol derivatives (5-8) was synthesized by reaction of compound(4) with formaldehyde , DMF as a solvent and different secondary amines. Preparation of new 1,2,4-triazoline derivatives (9) by reaction compound (4) with bromo acetic acid . Reaction of compound (9) with different aromatic aldehyde and dimethyl sulfoxide as a solvent obtained compounds (10-13)

Synthesis, Characterization and Study the Biological Activity of New Morpholine Derivative

A new series of morpholine derivative were prepared by reacting the morpholine with ethyl chloro acetate in the presence triethylamine as an catalyst and benzene as a solvent gave the ethyl morpholin-4-ylacetate reaction with hydrazine hydrate and ethanol as a solvent gave the 2-(morpholin-4-yl)acetohydrazide gave series of Schiff base were prepared by reacting 2-(morpholin-4- yl)acetohydrazide with different aromatic aldehydes and ketons . The new series of (3-9 )were synthesis by reaction of Schiff base (10-14) with chloroacetyl chloride, triethyl amine as an catalyst and 1,4dioxane as a solvent .The chemical structures of the synthesis compound were identified by spectral methods their [ IR ,1H-NMR and 13C-NMR ].The synthesised compounds were screened for antibacterial activity and antifungal activity promising by disc diffusion method by measuring the zone of inhibition and the results were compared to standard drugs ciprofloxacin

Cancer care in Singapore

Singapore is a small country, but it is ideally and centrally located to conveniently serve not only its population but also patients from the surrounding regions. It’s economy is sufficiently strong to maintain highly sophisticated and expensive equipment to manage a high level of healthcare, including oncology services

Finite sampling interval effects in Kramers-Moyal analysis

Large sampling intervals can affect reconstruction of Kramers-Moyal coefficients from data. A new method, which is direct, non-stochastic and exact up to numerical accuracy, can estimate these finite-time effects. For the first time, exact finite-time effects are described analytically for special cases; biologically inspired numerical examples are also worked through numerically. The approach developed here will permit better evaluation of Langevin or Fokker-Planck based models from data with large sampling intervals. It can also be used to predict the sampling intervals for which finite-time effects become significant.Comment: Preprin

Temperature measurements of fusion plasmas produced by petawatt laser-irradiated D2-3He or CD4-3He clustering gases

Two different methods have been employed to determine the plasma temperature in a laser-cluster fusion experiment on the Texas Petawatt laser. In the first, the temperature was derived from time-of-flight data of deuterium ions ejected from exploding D2 or CD4 clusters. In the second, the temperature was measured from the ratio of the rates of two different nuclear fusion reactions occurring in the plasma at the same time: D(d, 3He)n and 3He(d, p)4He. The temperatures determined by these two methods agree well, which indicates that: i) The ion energy distribution is not significantly distorted when ions travel in the disassembling plasma; ii) The kinetic energy of deuterium ions, especially the hottest part responsible for nuclear fusion, is well described by a near-Maxwellian distribution.Comment: 13 pages, 4 figure

Stochastic analysis of different rough surfaces

This paper shows in detail the application of a new stochastic approach for the characterization of surface height profiles, which is based on the theory of Markov processes. With this analysis we achieve a characterization of the scale dependent complexity of surface roughness by means of a Fokker-Planck or Langevin equation, providing the complete stochastic information of multiscale joint probabilities. The method is applied to several surfaces with different properties, for the purpose of showing the utility of this method in more details. In particular we show the evidence of Markov properties, and we estimate the parameters of the Fokker-Planck equation by pure, parameter-free data analysis. The resulting Fokker-Planck equations are verified by numerical reconstruction of conditional probability density functions. The results are compared with those from the analysis of multi-affine and extended multi-affine scaling properties which is often used for surface topographies. The different surface structures analysed here show in details advantages and disadvantages of these methods.Comment: Minor text changes to be identical with the published versio

Simulation of Behavior of Plate on Elastic Foundation under Impact Load by the Finite Element Method

Transient response and vibrations of an elastic plate resting on sandy soil are presented. Plates are commonly used structural elements and are subjected to wide variety of static and dynamic loads. Such studies are of particular interest in analytical investigations related to structural foundation on soil media. The influence of impact induced high strain-rates within the structure, which causes property changes in all used materials, has to be regarded according to experimental results.The main objective of the present paper, using the finite element approach through ANSYS program is the simulation of the dynamic response of the foundation under impact load. As a case study, previous experimental work included application of a dynamic load generated by dropping a steel ball (38.1 mm in diameter, 2.22 N in weight) from a height of 609.6 mm onto an aluminum target plate (203.2 mm in diameter, 12.7 mm thick) placed on top of a sand medium. The impact load is defined as a product of the loading magnitude and a time varying function which is assumed to be a Hanning's function for a monopeak, smooth-shaped curve. The problem is discretised by using four types of elements; Solid 45 to model the soil, Shell 63 to model the aluminum plate and Target 170 and Contact 174 are used to model the contact between the plate and soil. Shell 63 (elastic shell) has both bending and membrane capabilities.It is noticed that the finite element analysis agrees well with the experimental results throughout the entire range of behavior, and the difference in the ultimate displacement is about 6.2%. It can be concluded that ANSYS program is well suited for impact analyses of soil and structural dynamics problems in the non-linear range

Development of advanced Thomson spectrometers for nuclear fusion experiments initiated by laser

Thomson Spectrometers are devices capable to separate the several particle species (with distinct charge-to-mass ratio and energy) produced by the different regimes of laser-matter experiments. In this work we describe the development of advanced spectrometers for low and medium energy particles. In particular, they are suitable for protons in the 5 keV–2 MeV and 100 keV–10 MeV energy ranges, respectively. The new prototypes of spectrometers have been designed and built to have a high sensitivity and be adaptable to many experimental situations and configurations, and are tailored to the characterization of charged particles and products of nuclear fusion reactions initiated by high energy and intensity lasers. Details on the realized prototypes, on their characterization and testing, together with the first experimental results are discussed