De Laat J.,University of Poitiers |
Dao Y.H.,University of Poitiers |
Hamdi El Najjar N.,University of Poitiers |
Daou C.,Holy Spirit University of Kaslik
Water Research | Year: 2011
The decomposition rate of H 2O 2 by iron(III)-nitrilotriacetate complexes (Fe IIINTA) has been investigated over a large range of experimental conditions: 3 < pH < 11, [Fe(III)] T,0: 0.05-1 mM; [NTA] T,0/[Fe(III)] T,0 molar ratios: 1-250; [H 2O 2] 0: 1 mM-4 M) and concentrations of HO radical scavengers: 0-53 mM. Spectrophotometric analyses revealed that reactions of H 2O 2 with Fe IIINTA (1 mM) at neutral pH immediately lead to the formation of intermediates (presumably peroxocomplexes of Fe IIINTA) which absorb light in the region 350-600 nm where Fe IIINTA and H 2O 2 do not absorb. Kinetic experiments showed that the decomposition rates of H 2O 2 were first-order with respect to H 2O 2 and that the apparent first-order rate constants were found to be proportional to the total concentration of Fe IIINTA complexes, were at a maximum at pH 7.95 ± 0.10 and depend on the [NTA] T,0/[Fe(III)] T,0 and [H 2O 2] 0/[Fe(III)] T,0 molar ratios. The addition of increasing concentrations of tert-butanol or sodium bicarbonate significantly decreased the decomposition rate of H 2O 2, suggesting the involvement of HO radicals in the decomposition of H 2O 2. The decomposition of H 2O 2 by Fe IIINTA at neutral pH was accompanied by a production of dioxygen and by the oxidation of NTA. The degradation of the organic ligand during the course of the reaction led to a progressive decomplexation of Fe IIINTA followed by a subsequent precipitation of iron(III) oxyhydroxides and by a significant decrease in the catalytic activity of Fe(III) species for the decomposition of H 2O 2. © 2011 Elsevier Ltd.
Karavetian M.,Maastricht University |
de Vries N.,Maastricht University |
Rizk R.,Holy Spirit University of Kaslik |
Elzein H.,Lebanese National Kidney Registry
Nutrition Reviews | Year: 2014
Strategies to enhance knowledge of and adherence to dietary guidelines for management of hyperphosphatemia in hemodialysis patients have been studied extensively over the past decade. This review is the first to compile all of them (2003-2013) and conduct a meta-analysis through calculation of effect size, with the aim of identifying the optimal nutrition education methods for effective management of hyperphosphatemia in hemodialysis patients. The following strategies were identified as being effective in changing dietary behavior: 1) use of self-evaluation and self-regulation techniques within educational tools, along with easy-to-apply skills; 2) individualized counseling by a renal dietitian provided just before the hemodialysis session; 3) high-intensity education; and 4) long duration of interventions. Future studies should focus on conducting randomized controlled trials with powered samples to help generate stronger evidence. © 2014 International Life Sciences Institute.
Bouri E.,Holy Spirit University of Kaslik
Energy | Year: 2015
This paper examines the return and volatility linkages between oil prices and the Lebanese stock market by applying the newly developed VAR-GARCH (Vector Autoregressive-Generalized Autoregressive Conditional Heteroskedasticity) model to weekly data from 30 January 1998 to 30 May 2014. To better understand the impact of the global financial crisis, we divide the data into three sub-periods: the pre-crisis period (02 February 1998-28 December 2007), the crisis period (02 January 2008-30 June 2009), and the post-crisis period (01 July 2009-30 May 2014). Contrary to previous studies showing the two-way transmission of return and volatility from oil prices to the stock markets of oil-exporting countries, our empirical results for the whole period reveal weak unidirectional return and volatility transmissions from oil prices to the Lebanese stock market. While the interrelationship between oil prices and Lebanese stocks increased during the crisis, it eased significantly in the post-crisis period. Our empirical results are important for policymakers involved in shock prevention and for portfolio managers seeking optimal portfolio allocation. © 2015 Elsevier Ltd.
Bouri E.,Holy Spirit University of Kaslik
Energy Economics | Year: 2015
The role of oil price volatility in predicting the stock-market volatility of small oil-importing countries that have a substantial number of investors from neighboring oil-exporting countries remains unexplored. To refine our basic understanding of this role, this paper proposes a methodological extension of the recently developed causality-in-variance procedure and considers the case of Lebanon and Jordan. These two heavy importers of oil are interesting in the sense that they are located in a region with a large number of rich oil-exporting countries, so their stock markets are tied to oil-exporters by way of foreign investors. The conditional mean and variance of returns are modeled within an ARMAX-GARCH framework that accommodates three salient features of the data, namely: autocorrelation, day-of-the-week effects, and movements in international markets. For comparison purposes, the stock markets of Morocco and Tunisia are also included in the study. Empirical analyses highlight the dynamic effects of the global financial crisis on the volatility spillovers between oil and the stock markets of oil-importing countries and provide more insights into the seemingly contradictory effects of being oil-importers while having investors from oil-exporting countries. The main results indicate that the volatility spillover is much more apparent from the world oil market to the stock market of Jordan than the other way around, whereas oil volatility is not a good predictor of Lebanese stock market volatility. Finally, policy/practical implications and conclusions for future research are drawn. © 2015 Elsevier B.V.
Abou-Elailah A.,Orange S.A. |
Dufaux F.,Orange S.A. |
Farah J.,Holy Spirit University of Kaslik |
Cagnazzo M.,Orange S.A. |
Pesquet-Popescu B.,Orange S.A.
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2013
The quality of side information plays a key role in distributed video coding. In this paper, we propose a new approach that consists of combining global and local motion compensation at the decoder side. The parameters of the global motion are estimated at the encoder using scale invariant feature transform features. Those estimated parameters are sent to the decoder in order to generate a globally motion compensated side information. Conversely, a locally motion compensated side information is generated at the decoder based on motion-compensated temporal interpolation of neighboring reference frames. Moreover, an improved fusion of global and local side information during the decoding process is achieved using the partially decoded Wyner-Ziv frame and decoded reference frames. The proposed technique improves significantly the quality of the side information, especially for sequences containing high global motion. Experimental results show that, as far as the rate-distortion performance is concerned, the proposed approach can achieve a PSNR improvement of up to 1.9 dB for a Group of Pictures (GOP) size of 2, and up to 4.65 dB for larger GOP sizes, with respect to the reference DISCOVER codec. © 1991-2012 IEEE.