6 research outputs found
Statistical modeling of monthly rainfall variability in Soummam watershed of Algeria, between 1967 and 2018
AbstractThe monthly precipitations obtained during 51 years of measurement in 24 stations of Soummam watershed in Algeria were analyzed to describe rainfall trends and aridity state of the area using statistical modeling. The choice of distribution laws was justified by comparing fitting results of different distributions laws used in literature reviews. Hence, the p values proved that Generalized Extreme Value, Weibull (3) and Logistic the distribution law are more adequate to analyze rainfall frequencies in different part of the watershed. The diagnostic given by QâQ plot, PâP plot and survival regression curve showed the period of wetness and dryness in the northeastern and the southwestern part of the watershed, respectively. Moreover, the study given by the De Martonne index explains the consequences of climate change by a new form of aridity in the watershed between 1994 and 2018.Recommendations for Resource Managers
The annual rainfall of Soummam watershed has a moderate and irregular rainfall distribution between 1967 and 2018.
Using distribution function on monthly rainfall in each bioclimatic floor to analyze the trend of rainfall frequency gives a spatioâtemporal description of climate in the area.
Fitting by KolmogorovâSmirnov test allows us to choose generalized extreme value, Weibull (3) and Logistic for modeling monthly rainfall variability in each part of the watershed.
The diagnostic obtained by PâP plot, QâQ plot and survival regression curve proved a change of aridity in the northeastern and southwestern part of the watershed between 1994 and 2018
A new approach for processing climate missing databases applied to daily rainfall data in Soummam watershed, Algeria
Missing data is a very frequent problem in climatology, it influences on the quality of results that will afford in hydrological studies, as well as water resources management. This paper proposes a new imputation algorithm, based on the optimization of some regression methods, which are hot deck, k-nearest-neighbors imputation, weighted k-nearest-neighbors imputation, multiple imputation, linear regression and simple average method. The choice of these methods was justified by qualitative and quantitative statistical tests analysis. However, the reliability of obtained results depends mainly on percentage of missing data, choice of neighboring stations and data missingness mechanism which should be missing at random. During the study it was found that the most of stations in Soummam watershed don't have a good correlation because the large loss in rainfall data or the geology of watershed which gives a relationship between station position and rainfall variability. For this case, principal component analysis is applied on a set of stations; it showed a positive impact of altitude, latitude and longitude on correlation index between selected stations. The graphical analysis of the normal law on RMSE values, which were obtained by applying the proposed technique in several random cases of missingness, that are 4%, 8%, 12% and 16% respectively, it confirmed the validity and the performance of this approach
Anti-Inflammatory and Antioxidant Effect of a D-galactose-rich Polysaccharide Extracted From Aloe vera Leaves
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Extraction, characterization and gelling behavior enhancement of pectins from the cladodes of Opuntia ficus indica
International audienceTotal Pectins Fraction (TPF) was extracted at room temperature from dried cladodes of Opuntia ficus indica. TPF is constituted of three pectic fractions WSP, CSP and ASP, which are made up of 66.6%, 44.3% and 81.1% (w/w) of galacturonic acid, respectively. The antioxidant ability of TPF increased with the concentration increasing. It scavenged hydroxyl radical by 90% and chelated 90% of ferrous ions at 5 g/L. FTIR study was carried out. Strong characteristic absorption peaks at 1618 cmâ1 assigned to the vibration of COOâ group of galacturonic acid. In the fingerprint region, we noticed three well-defined peaks at 1054, 1085, and 1154 cmâ1 characteristic of pectic polysaccharides. TPF are non-gelling pectins. The co-crosslinking of TPF with carrageenan was carried out and the gelling behavior was successfully improved. Thermo-sensitive hydrogel was obtained with 82% of TPF and 18% of carrageenan (w/w)