567 results for “coefficient”

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Research ArticleOpen accessIn the abstractA Model for Bioaccumulation of Metals in Crassostrea virginica from Apalachicola Bay, FloridaDennis A. Apeti, Elijah Johnson, Larry RobinsonKinetics of bioaccumulation of the trace metals (Cd and Zn) by C. virginica were investigated in this study. A computer program, Oyster Bioaccumulation Model (OBM), was developed to simulate the accumulation of the metals from both dissolved (water column) and particulate (food) phases by C. virginica. The model is based on two main attributes: (1) the oyster biological characteristics such … …American Journal of Environmental Sciences, Vol. 1, Issue 3 · 30 Sep 2005 · 7,474 accessesView PDF Cite

Research ArticleOpen accessIn the abstractβ-Spline Estimation in a Semiparametric Regression Model with Nonlinear Time Series ErrorsJinhong You, Gemai Chen, Xian ZhouWe study the estimation problems for a partly linear regression model with a nonlinear time series error structure. The model consists of a parametric linear component for the regression coefficients and a nonparametric nonlinear component. The random errors are unobservable and modeled by a first-order Markov bilinear process. Based on a B-spline series approximation of the nonlinear component function, we … …American Journal of Applied Sciences, Vol. 2, Issue 9 · 30 Sep 2005 · 6,734 accessesView PDF Cite

Research ArticleOpen accessIn the abstractAn HIV/AIDS Model with Variable Force of Infection and its Application to the Epidemic in UgandaFlugentius Baryarama, Joseph Y.T. Mugisha, Livingstone S. LuboobiAn HIV/AIDS model is formulated with variable force of infection for the adult population. Its actions are reduced to a prevalence equation that is a non-logistic equation whose explicit solution is derived. The implications of applying the solution to the evolution of the HIV/AIDS epidemic are discussed with respect to the positive boundedness of the coefficients. Prevalence projections are presented … …American Journal of Applied Sciences, Vol. 2, Issue 9 · 30 Sep 2005 · 6,964 accessesView PDF Cite

Research ArticleOpen accessIn the abstractOn the Relations among Characteristic Functions of Theta FunctionsIsmet Yildiz, Neslihan UyanikIn this study, using the characteristic values $\begin{bmatrix} \varepsilon\\ \varepsilon' \end{bmatrix} = \begin{bmatrix} 1\\ 1 \end{bmatrix}, \begin{bmatrix} 1\\ 0 \end{bmatrix}, \begin{bmatrix} 0\\ 1 \end{bmatrix}, \begin{bmatrix} 0\\ 0 \end{bmatrix} \pmod 2$ a theorem on the $\frac{1}{2^r}$ coefficients of periods of first order theta function according to the $(1,τ)$ period pair (for $r \in N^+$) is established. The following equalities are also … …Journal of Mathematics and Statistics, Vol. 1, Issue 2 · 30 Jun 2005 · 6,040 accessesView PDF Cite

Research ArticleOpen accessIn the abstractSpectrofluorimetric, Atomic Absorption Spectrometric and Spectrophotometric Determination of Some FluoroquinolonesHesham SalemSimple, accurate, sensitive and selective spectrofluorimetric, atomic absorption spectrometric and spectrophotometric methods are described for the quantitative determination of ten fluoroquinolones (amifloxacin, ciprofloxacin hydrochloride, difloxacin hydrochloride, enoxacin, enrofloxacin, lomefloxacin hydrochloride, levofloxacin, norfloxacin, ofloxacin and pefloxacin mesylate). The first method was a spectrofluorimetric method in which samples of the studied drugs in 0.1 N H2SO4 showed native fluorescence at 450 nm … …American Journal of Applied Sciences, Vol. 2, Issue 3 · 31 Mar 2005 · 7,317 accessesView PDF Cite

Research ArticleOpen accessIn the abstractOn Fractional Hold Devices Versus Positive Realness of Discrete Transfer FunctionsM. de la Sen, A. Bilbao- GuillernaThe appropriate use of fractional order holds (β-FROH) of correcting gains βε[-1,1] as an alternative to the classical zero and first order -holds (ZOH, FOH) is discussed related to the positive realness of the associate discrete transfer functions obtained from a given continuous transfer function. It is proved that the minimum direct input-output gain (i.e. the quotient of the leading … …American Journal of Applied Sciences, Vol. 2, Issue 3 · 31 Mar 2005 · 7,189 accessesView PDF Cite

Research ArticleOpen accessIn the abstractSimulation of Thermal Stratification in Urban Man-made LakesJ. Nouri, H. Rahimipour, R. NezakatiChitgar artificial lake, located in the urban District-22 Municipality of Tehran northwest of Tehran, Iran is by volume l0 Million Cubic Meter (MCM), by depth average 10 meters (m.) and by area 225 hectares (ha) as the Iran’s largest man-made lake. The most important water resources of the district, which can support the lake water, are Kan River, municipal runoff, … …American Journal of Applied Sciences, Vol. 1, Issue 4 · 31 Dec 2004 · 7,189 accessesView PDF Cite