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In recent years, magnesium oxide (MgO) has been considered by researchers as a new agent for the remediation of contaminated soils. In this paper, the effect of MgO and hydrated lime on the remediation of a clay soil contaminated with MTBE (Methyl Butyl Ether) was studied. The contaminated soil was made artificially by adding 2.25 g MTBE per kg of soil. MgO with different percentages (0.125, 0.25, 0.5, 5, 10, and 20%) and lime with 2.5, 5, and 10% percentages were added to the natural and contaminated soil. The results showed that by increasing the percentage of MgO or lime and curing time, the strength of natural and contaminated soil was improved. The results of the leaching tests showed that by adding 5, 10, or 20% MgO, all the existing MTBE in the soil samples were removed while for the smaller percentages of MgO (0.125, 0.25, and 0.5%) there was a decrease in the concentration of MTBE with time. The results of the leaching tests also revealed that the hydrated lime was effective in reducing the concentration of MTBE. The amount of reduction in the concentration of MTBE was dependent on the percentage of MgO or hydrated lime. The comparison of the results of the two binders showed that MgO was more effective than the hydrated lime in removing the MTBE from the soil. [ABSTRACT FROM AUTHOR]

Independence test based on empirical copula does not perform well in the presence of weak dependency or when dependency occurs only in the tails. The copula density, which is estimated by a local likelihood probit transformation method, is used to detect the independence. In this article, three nonparametric tests of independence based on α-divergence and copula density are introduced. These tests are capable of considering weak dependency. The asymptotic consistency of the copula-based α-divergence estimator is also derived. In addition, the empirical powers of the proposed tests are computed through extensive simulations. The results show that the new tests outperform in small sample sizes or weak dependencies. Finally, an application in uranium exploration is presented to illustrate the applicability of the proposed tests. [ABSTRACT FROM AUTHOR]

In this article, we provide a probabilistic proof to the strengthened Hardy's integral inequality given in text. We also provide the upper and lower bounds for expectation of functions of hazard rate, mean residual life, eta function and intensity function. Moreover, an upper bound for extropy and cumulative residual extropy is obtained based on Hardy's inequality. Furthermore, we obtain upper bounds for cumulative residual Tsallis entropy of series and parallel systems. [ABSTRACT FROM AUTHOR]

In this paper, a new dependent model is introduced. The model is motivated using the structure of series-parallel systems consisting of two series-parallel systems with a random number of parallel sub-systems that have fixed components connected in series. The dependence properties of the proposed model are studied. Two estimation methods, namely the moment method, and the maximum likelihood method are applied to estimate the parameters of the distributions of the components based on observing the system's lifetime data. A Monte Carlo simulation study is used to evaluate the performance of the estimators. Two real data sets are used to illustrate the proposed method. The results are useful for researchers and practitioners interested in analyzing bivariate data related to extreme events. [ABSTRACT FROM AUTHOR]

In this paper, we study the asymptotic behavior of the kernel bivariate distribution function estimator for negatively superadditive dependent. The exponential convergence rates for the kernel estimator are investigated. Under certain regularity conditions, the optimal bandwidth rate is determined with respect to mean squared error criteria. A simulation study is used to justify the behavior of the kernel and histogram estimators. As an application, a real data set in hydrology is considered and the kernel bivariate distribution function estimator of the data is investigated. [ABSTRACT FROM AUTHOR]

This paper presents an investigation into the behaviour of a clay soil stabilised with MgO under forced carbonation and comparison with conventional chemical stabilisation methods. The tests were conducted in two groups. In the first group the soil was mixed with 5, 10, 15 and 20% MgO or cement. Unconfined compressive strength (UCS) tests were performed on compacted samples from these mixtures at curing times of 7, 14 and 28 days. In the second group, samples prepared with different percents of MgO were subjected to CO2 under pressures of 0.5, 1.0 and 1.5 bar for periods of 4, 8, 12 and 24 h. The results showed that adding MgO increases the strength of the soil and, like other binders, the amount of increase in strength depends on the percent of MgO and curing time. It is also resulted that the effect of MgO is less than cement in increasing the strength. It was revealed that forced carbonation can facilitate the stabilisation of MgO-stabilised soil in a few hours compared with usual process that takes several days. XRD and SEM results showed that the gained strength is resulted from the interaction between the soil and the agents. [ABSTRACT FROM AUTHOR]

Lateral flow immunoassay (LFIA) is the most widely used platform of the point-of-care (POC) detection. Since the most important factor in deciding the results of this technique is the visual quality of the test, it should be at its optimum. To address this issue, the present study examines optimising critical parameters to improve the quality of LFIA performance. In this regard the penicillin-binding protein 2a (PBP2a) in methicillin-resistant staphylococcus aureus (MRSA) was selected as a bacterial model. The targeted parameters included a) size of gold nanoparticles (AuNP), b) antibody conjugation conditions with AuNP, c) antibody concentrations in the capturing zones, d) the effects of blocking substances and different chemical buffers for pre-treatment of the strips. Visual quality of different manufactured strips revealed that the diameter of 14 ± 2, PH = 9.5 was the optimum for improvement of MRSA detection quality. The optimum concentration of labelling antibody in conjugate pad and concentration of the capturing antibody in the test band were 40 µg/ml and 1.1 µg/μl in PBS buffer (pH 7.4) respectively. In conclusion by finding the critical factors affecting the detection limit of lateral flow and optimising them, the visual quality of LFIA results can be increased. [ABSTRACT FROM AUTHOR]

In this paper we establish Kolmogrov–Feller weak law of large numbers for maximal weighted sums of i.i.d. random variables. [ABSTRACT FROM AUTHOR]

In this paper, the kernel density estimator for negatively superadditive dependent random variables is studied. The exponential inequalities and the exponential rate for the kernel estimator of density function with a uniform version, over compact sets are investigated. Also, the optimal bandwidth rate of the estimator is obtained using mean integrated squared error. The results are generalized and used to improve the ones obtained for the case of associated sequences. As an application, FGM sequences that fulfil our assumptions are investigated. Also, the convergence rate of the kernel density estimator is illustrated via a simulation study. Moreover, a real data analysis is presented. [ABSTRACT FROM AUTHOR]

Researchers have been developing various extensions and modified forms of the Weibull distribution to enhance its capability for modeling and fitting different data sets. In this note, we investigate the potential usefulness of the new modification to the standard Weibull distribution called odd Weibull distribution in income economic inequality studies. Some mathematical and statistical properties of this model are proposed. We obtain explicit expressions for the first incomplete moment, quantile function, Lorenz and Zenga curves and related inequality indices. In addition to the well-known stochastic order based on Lorenz curve, the stochastic order based on Zenga curve is considered. Since the new generalized Weibull distribution seems to be suitable to model wealth, financial, actuarial and especially income distributions, these findings are fundamental in the understanding of how parameter values are related to inequality. Also, the estimation of parameters by maximum likelihood and moment methods is discussed. Finally, this distribution has been fitted to United States and Austrian income data sets and has been found to fit remarkably well in compare with the other widely used income models. [ABSTRACT FROM AUTHOR]

In this note, we introduce a new class of dependent random variables (henceforth rvs), together with some its basic properties. This class includes independent rvs and pairwise negatively dependent rvs. Some extensions of Ranjbar et al. (2008) are discussed. The complete convergence for the new class of rvs is also proved, and some results of Beak and Park (2010) are extended to this class conveniently. [ABSTRACT FROM AUTHOR]

Two systems of polypropylene (PP), poly(lactic acid) (PLA) and ethylene vinyl alcohol copolymer (EVOH) ternary blends having different compositions were extruded in a co-rotating twin screw extruder. The first system was PP/PLA (75/25) with various EVOH contents, the second one was PP/EVOH (75/25) having various PLA contents. The effects of composition on the morphology and the tensile and impact properties of the blends were investigated. There were increases in the tensile modulus and tensile strength with an increase in the EVOH and PLA contents in the first and second systems, respectively. A molecular dynamics (MD) simulation was used to investigate the compatibility between the components. Prediction of the miscibility of the blends was carried out by determining the interaction parameters (x), mixing energies (DHmix), phase diagrams and Gibbs free energies. The MD simulation showed a UCST behavior for the components. Moreover, the simulation results showed a compatibilizer effect for the EVOH component. The experimental values of the dynamic mechanical thermal analysis (DMTA) and mechanical properties were correlated to the MD results. There was a good correlation between the MD and DMTA results. The modulus values using the parallel and Davis models were near to the experimental ones. A good fitting to the mixture law with addition of EVOH confirmed a good compatibilzing effect of it between the PP and PLA components. [ABSTRACT FROM AUTHOR]

In this work, a functionalized mesoporous carbon (CMK-3-O) was synthesized after oxidation with nitric acid and was used to adsorb dibenzothiophene (DBT) from model oil for the first time. Then, its performance was compared with that of CMK-3. The functionalized mesoporous carbon, CMK-3-O, showed better a capacitance performance for DBT adsorption than that of CMK-3. The maximum adsorption capacity was obtained for functionalized mesoporous carbon at optimum conditions with 6 M HNO3aqueous solution and 30 min contact time. The physical and structural properties of CMK-3-O and CMK-3 were investigated with X-ray diffraction method (XRD), N2adsorption–desorption isotherm, FT-IR, and elemental analysis (CHNO). Results of the elemental analysis showed that the oxygen and nitrogen content has increased and the carbon content has decreased through oxidation treatment. The effects of various factors on the adsorption process (such as temperature, amount of adsorbent, contact time, and concentration) of DBT were studied. CMK-3-O showed a maximum adsorption capacity of 86.96 mg DBT g−1of CMK-3-O at optimized conditions (temperature, 25°C; adsorbent dosage, 20 g L−1; contact time, 60 min), which was a higher adsorption capacity of that observed for CMK-3 (57.47 mg DBT g−1of CMK-3). Kinetic studies have revealed that the adsorption of DBT can be described by a pseudo-second-order rate equation. Equilibrium data showed that adsorption process was best represented by the Langmuir model. The results also illustrated the fact that the regenerated adsorbent afforded 64.3% of the initial adsorption capacity after the two regeneration cycles. [ABSTRACT FROM PUBLISHER]

In this paper, we introduce a new positive dependence concept between two non negative random variables which is related to a conditional version of the mean inactivity time order. A number of properties and relationship between the new notion and the concept of positive likelihood ratio dependence (PLRD) is discussed. Some results in terms of proposed notions for the Archimedean family of copulas are provided. [ABSTRACT FROM PUBLISHER]

In this work, a functionalized mesoporous carbon (CMK-3-O) was synthesized after oxidation with nitric acid and was used to adsorb dibenzothiophene (DBT) from model oil for the first time. Then, its performance was compared with that of CMK-3. The functionalized mesoporous carbon, CMK-3-O, showed better a capacitance performance for DBT adsorption than that of CMK-3. The maximum adsorption capacity was obtained for functionalized mesoporous carbon at optimum conditions with 6 M HNO3aqueous solution and 30 min contact time. The physical and structural properties of CMK-3-O and CMK-3 were investigated with X-ray diffraction method (XRD), N2adsorption–desorption isotherm, FT-IR, and elemental analysis (CHNO). Results of the elemental analysis showed that the oxygen and nitrogen content has increased and the carbon content has decreased through oxidation treatment. The effects of various factors on the adsorption process (such as temperature, amount of adsorbent, contact time, and concentration) of DBT were studied. CMK-3-O showed a maximum adsorption capacity of 86.96 mg DBT g−1of CMK-3-O at optimized conditions (temperature, 25°C; adsorbent dosage, 20 g L−1; contact time, 60 min), which was a higher adsorption capacity of that observed for CMK-3 (57.47 mg DBT g−1of CMK-3). Kinetic studies have revealed that the adsorption of DBT can be described by a pseudo-second-order rate equation. Equilibrium data showed that adsorption process was best represented by the Langmuir model. The results also illustrated the fact that the regenerated adsorbent afforded 64.3% of the initial adsorption capacity after the two regeneration cycles. [ABSTRACT FROM AUTHOR]

Baker (2008) introduced a new method for constructing multivariate distributions with given marginals based on order statistics. In this paper, we provide a test of independence for a pair of absolutely continuous random variables (X,Y) jointly distributed according to Baker’s bivariate distributions. Our purpose is to test the hypothesis thatXandYare independent versus the alternative thatXandYare positively (negatively) quadrant dependent. The asymptotic distribution of the proposed test statistic is investigated. Also, the powers of the proposed test and the class of distribution-free tests proposed by Kochar and Gupta (1987) are compared empirically via a simulation study. [ABSTRACT FROM AUTHOR]

This paper considers a class of absolutely continuous bivariate exponential distributions whose univariate margins are the ordinary exponential distributions. We study different mathematical properties of the proposed model. The estimation of the parameters by maximum likelihood is discussed. Application is made to a real data example to illustrate the flexibility of theproposed distribution for data analysis. [ABSTRACT FROM AUTHOR]

In this paper, we provide conditions under which some bivariate dependence structures are preserved under bivariate weighted distributions. Bivariate weighted distributions whose dependence structure is the same as the original distribution are characterized. Finally, we discuss some examples to show the usefulness of our results. [ABSTRACT FROM AUTHOR]

A bivariate family of copulas has been initiated by Cuadras-Augé (1981) and Marshall (1996). Recently, Durante (2007) considered this family as a general family of symmetric bivariate copulas indexed by a generator function and studied some of its dependence properties. In this article, we obtain and describe further aspects of dependence for this family. For example, we have proved that the family has positive likelihood ratio dependence structure if and only if the family reduces to some well-known copulas. We also derive several proper forms for the generator function of this family. Considering a multivariate extension of the bivariate family of copulas provided by Durante et al. (2007), some dependence properties are studied. Finally, some positive dependence stochastic orderings for two random vectors having a copula from the proposed families, are discussed. [ABSTRACT FROM PUBLISHER]

The extractive desulfurization of a model and several real gasoline samples was investigated using imidazolium-based ionic liquids (ILs). Factorial design of experiments indicated that, among several process variables, the number of extraction steps and the IL/gasoline volume ratio were statistically highly significant. The results showed a desulfurization efficiency of 95.2% under the optimal conditions. The following order was observed for the extraction of thiophenic compounds: benzothiophene>thiophene>3-methylthiophene>2-methylthiophene, with 96.1% removal efficiency for the first one. The IL extraction was applied as a complementary process for the oxidative desulfurization by hydrogen peroxide and formic acid, which provided high efficiency and selectivity for desulfurization of gasoline. [ABSTRACT FROM PUBLISHER]

In this article, we apply univariate characterizations of some monotonic aging classes to investigate the preseiyation problem of those classes and stochastic orders under weighting. The results are also examined and discussed for special cases of the weighted distributions, as well. [ABSTRACT FROM AUTHOR]

Silver doped TiO2 nanocomposite [1% (w/w)] and undoped nano-TiO2 particles were prepared by sol-gel method from tetraporopyl orthotitanate as the precursor. To improve the photocatalytic efficiency, silver doped TiO2 nanoparticles were immobilised on NaX zeolite and used as photocatalyst. Chemical composition and optical absorption of the photocatalyst were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared and ultraviolet-visible absorption spectroscopy. The XRD patterns show that the supported TiO2 are crystallised in anatase phase, and the intensity of the zeolite peaks decreases with the increase in TiO2 loading. Characterisation of samples by SEM indicates that the outer surface of the zeolite crystals is covered by the titania particles. Infrared spectroscopy revealed that the nanosize titanium oxide particles are linked to the framework through Ti-O-Si bonds. Ultraviolet-visible diffuse reflectance spectrum of metal doped TiO2 nanocomposite shows red shift in the band gap transition. The photocatalytic performances of these composite semiconductors were examined with respect to an azo dye, Orange G. The effects of pH and irradiation time on photodegradation were investigated. According to the UV-vis absorption spectroscopy results, the photodegradation of orange G dye under UV light irradiation in the presence of silver doped TiO2/NaX zeolite catalyst is more efficient than the Ag/TiO2 nanocomposite and also undoped nanotitanium oxide powder. [ABSTRACT FROM AUTHOR]

In this article, several counterexamples are provided which show that some concepts of negative dependence are strictly stronger than others. An open problem is solved which was posed by Hu et al. (2005) and refers to whether strong negative orthant dependence implies the negative superadditive dependence. Finally, for a dependence random vector (X1, X2,..., Xn) (n ⩾2), we construct uncorrelated random variables Yi = Xt, + cUi a.e. i = 1,2, ...,n under certain dependence structures, where the vector U = (U1, U2,..., Un) is independent of (X1,X2,...Xn). [ABSTRACT FROM AUTHOR]

The simultaneous analysis of dithiocarbamate fungicide residues on greenhouse and non-greenhouse tomatoes was performed by high-performance liquid chromatography with UV detection. A calibration curve with spiked samples was plotted to determine dithiocarbamate residues in tomato samples. Limits of detection and quantification were approximately 0.05 and 0.2 µg g−1, respectively. The ranges of mean recoveries at five spiking levels for all dithiocarbamates of interest were between 88.2%–95.7% and 99.5%–100.8% in standards and spiked samples, respectively. In this study, 40 greenhouse and 40 non-greenhouse tomato samples were analysed. None of the samples analysed contained dithiocarbamates in excess of the maximum residue levels established by the Codex Committee on Pesticide Residues, except for one greenhouse sample, with ethylenebisdithiocarbamates at 3.2 µg g−1. [ABSTRACT FROM PUBLISHER]

In this article, we obtained a dependence measure for generalized Farlie-Gumbel-Morgenstern (FGM) family in view of Kochar and Gupta (1987) and then compared this measure with Spearman's rho and Kendall's tau in FGM family. Moreover, we evaluated the empirical power of the class of distribution-free tests proposed by Kochar and Gupta (1987, 1990) based on exact distribution of a U-statistics. This is derived via a simulation study for sample of sizes n = 6, 8, 10, 12, 16, and 20. Also, we compared our simulation results with those achieved by Amini et al. (2010) and Guven and Kotz (2008). [ABSTRACT FROM AUTHOR]

The application of the modified MCM-41 and SBA-15 nanporous silicas in extraction of trace amounts of palladium is investigated and developed. Surface of nanoporous silicas, MCM-41 and SBA-15, were modified with 9-acridinylamine ligand and then utilized as solid-phase sorbents for the extraction of palladium. Different experimental conditions such as pH, flow rates of the sample, and eluent solution were studied. The type and the smallest amount of eluent for elution were optimized and the breakthrough volume and the influence of various cationic interferences on the adsorption was investigated. The recovery values in this method are greater than 95% and 98.5%. The obtained limits of detections (LOD) are lower than 0.17 ng mL-1 and 0.15 ng mL-1 for SBA-15 and MCM-41, respectively. The pre-concentration factors were calculated to be more than 193 and 187.5 for SBA-15 and MCM-41, respectively. The relative standard deviations (RSD) of the method are lower than 4% and 1.5%, and the adsorption capacities were also obtained to be more than 170 mg g-1 and 195 mg g-1 for SBA-15 and MCM-41, respectively. The proposed procedure was applied on real samples and the amount of palladium was successfully derived. [ABSTRACT FROM AUTHOR]

A hydrodistillation sampling method, coupled to gas chromatography-mass spectrometry, was used in monitoring the volatile organic compounds in flowers of Astragalus sahendi. Accordingly, a total of 48 compounds were recognised, which were united by their terpenoid or aliphatic skeletons and low molecular weight. Above all, the significant presence of some insect-favoured terpenoid compounds, such as farnesol, cis- and trans-geraniol, α-bisabolol, nerolidol isomer, α-terpineol, α-terpinolene and thymol was significant. These findings confer a better understanding of pollination processes in the giant genus Astragalus. Furthermore, the results add to an increasing quantity of data corroborating the ecologic and evolutionary correlation between the floral bioactive compounds of plant species and their special types of pollinators. [ABSTRACT FROM AUTHOR]

In this article, we study the dependence structure of Cuadras-Auge (C-A) family of bivariate distributions. We also obtain some association measures and two local dependence functions for this family. In addition, we compare expectation of local dependence function and Pearson's rho via numerical study. [ABSTRACT FROM AUTHOR]

Androgenic steroids always exist in different animal tissues at trace level, with significant numbers of interfering compounds, which makes their determination difficult. To solve some of the problems in quantification of the natural steroids in those tissues, a new GC-MS method was developed in this study. By using a surrogate analyte approach, which was developed in the authors' previous studies, and extensive sample preparation procedure, which successfully eliminates many of the interfering compounds and resulting in a cleaner extract, accuracy, precision, sensitivity and selectivity of the method for the determination of steroids in complex matrices such as meat, liver and testis were improved. By aid of this method, the levels of androgens in different tissues of Iranian native cross-breed bulls and male sheep were determined. According to the results obtained in the present study, although the androgenic profile (contents and ratios of precursors and metabolites to the main hormones) is similar between the same tissues of both animals, the total androgenic content of each tissue is higher in the bull than the same tissue in male sheep. In addition, in both animals higher amount of androgens were found in liver in comparison with meat and testis. [ABSTRACT FROM AUTHOR]

Seventy-one cases that had resulted borderline for HER-2 protein expression at conventional immunohistochemical assay (2+) were assessed for HER-2 gene amplification by real-time PCR and by FISH in accordance with the manufacturer's recommendations (gene amplification with ratio ≥2 in both methods). Thirty-three out of 71 cases (47%) resulted amplified at real-time PCR analysis, whereas 15 cases resulted positive at FISH (21%). Apparently, PCR was more sensitive than FISH in HER-2 determination, only 10 cases resulting amplified in both tests. When the mean ratio value obtained in all PCR experiments was adopted as threshold in determining HER-2 gene amplification, the apparent sensitivity of PCR was reduced but correlation between PCR and FISH results was dramatically increased. Furthermore, when the mean PCR ratio value observed in the FISH-positive group was chosen as threshold, the best agreement between PCR and FISH results was achieved. Therefore, we found that the proposed threshold ratio value of ≥2 is not accurate in separating HER-2 amplified and non-amplified cases. We suggest that the threshold ratio value in PCR tests should be determined in each laboratory using FISH controlled cases. Finally, above certain in-lab generated threshold values, PCR might be proposed as a highly predictive positive test in HER-2 assessment. [ABSTRACT FROM AUTHOR]

In this paper we study the strong law of large numbers for the weighted sums Tn = Σk=1∞ankXk where {Xn, n ≥ 1} is a sequence of negative dependent generalized Gaussian random variables under the condition that E[Xn||Fn-1 = 0, Fn = σ(X1,..., Xn and ank is an array of nonnegative real numbers such that for each n ≥ 1, An = Σk=1∞ ank² < ∞. [ABSTRACT FROM AUTHOR]

Silver ion-selective electrodes based on 2-mercaptobenzimidazole (MBI) and 2-mercaptobenzothiazole (MBT) carriers have been developed. The poly(vinyl chloride) (PVC)-based membranes containing MBI or MBT, plasticizer and sodium tetraphenylborate, as anion excluder and membrane modifier, were directly coated on the surface of graphite electrodes. The electrodes exhibited near-Nernstian slopes of 60.2 and 57.8 mV per decade of Ag[sup +] concentration for MBI and MBT, respectively. Calibration plots were linear over a wide concentration range of 1 x 10[sup -6]-1 x 10[sup -2]M Ag[sup +]. The electrodes have shown detection limits of 6.3 x 10[sup -7] and 4 x 10[sup -7]M for MBI- and MBT-based electrodes, respectively, and revealed good selectivities over a number of alkali, alkaline earth, transition and heavy metal ions. The electrodes have response times between 10-20 s and can be used for at least two months without a considerable divergence in their potential responses Application of the electrodes for potentiometric titrations and determination of Ag[sup +] ion concentration in photographic waste solutions are reported. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in which the letter writers discuss the use of the Dundee three-circle model for evaluating the quality of medical education.