Modélisation pluie-débit à l’échelle annuelle en Algérie du nord

La modélisation du comportement hydrologique des bassins versants est incontournable dès lors que l'on s'intéresse à des problématiques relatives à l’évaluation et la gestion optimale des ressources en eau. Ceci s’illustre par un aspect quantitatif, dans les pays comme l’Algérie où l’alimentation en eau est un facteur limitant. L’objectif principal de cet article est d’expliciter les relations entre les conditions hydrologiques et la disponibilité en eau de surface. A cet effet, un modèle pluie-débit à l’échelle annuelle qui prend en compte les paramètres physiques et climatiques a été mis au point. L’application porte sur l’Algérie du Nord dont la superficie est de 325 000 km2.La mise au point de ce modèle nécessite au préalable une base de données qui a été acquise lors des travaux antérieurs incluant la carte des pluies médianes, la carte des perméabilités et le modèle numérique de terrain. Afin de compléter cette base de données, la cartographie des pluies des différentes années pour lesquelles on dispose des débits a été réalisée en utilisant une méthodologie intitulée "cartographie de la pluie centrée réduite". Ainsi, les données de 467 postes pluviométriques ont été traitées et ont permis de tracer les cartes des isohyètes annuelles.L’étude de la relation pluie-débit à l’échelle annuelle est basée sur les données de débits de 50 stations hydrométriques réparties à travers la zone d’étude. La démarche utilisée s’est inspirée de la fonction de production du S.C.S (Soil Conservation Service). Les résultats du modèle après calage ont permis d’obtenir un coefficient d’explication de 0,75, ce qui signifie que 75 % de la variance est expliquée par la pluie moyenne, la surface et un coefficient (a) qui correspond à la pente moyenne des bassins versants.Modelling the hydrological behaviour of drainage basins is very important for solving problems related to the evaluation and optimal management of water resources. This is illustrated quantitatively in countries such as Algeria where water supply is a limiting factor. The principal aim of this paper was to explain the relationship between hydrological conditions and the availability of surface water. A model of rainfall-discharge was developed on a yearly scale, taking into account physical and climatic parameters. The application was carried out in northern Algeria where the total land surface is about 325 000 km2.The development of this model required a database, which was acquired during previous studies where maps of median rainfall and permeability as well as the digital elevation model were developed. In order to complete this database, the cartography of rainfall for the years for which we have discharge data was carried out using a methodology entitled "mapping standardized rainfall". To estimate and map annual rainfall, the kriging method was used. Two problems were encountered:- The presence of a drift highly altered the variogram and made it very difficult to infer a sub- structure function;- The variogram is significant only if the hypothesis of ergodicity is valid, which was not easy to assume for any given year.In order to resolve these difficulties, a homogeneous random and secondary stationary order function (same mean at all points and same covariance function) must be calculated. A previous study by ANRH (1993) allowed us to know the statistical parameters of the distribution at each point. These parameters were mapped, taking into consideration the topographical relief and distance to the sea. For every year and at each rainfall measure point, the standardized rainfall could be deduced. The correlogram gave information about the spatial variability of the phenomenon and its range, and subsequently the standardized rainfall was then interpolated. Annual rainfall was calculated by combining the grids of the means, the variances and the centered reduced rainfall (TOUAZI and LABORDE, 2000). Thus, the data of 467 rainfall gauges were used in order to create maps of the yearly isohyets.The rainfall-discharge relationship on an annual scale was based on 50 hydrometric stations distributed throughout the study area. The methodology used was derived from the production function of the S.C.S (Soil Conservation Service). This production function was part of modelling, which transformed total rainfall to net rainfall. This method was very representative of the natural hydrological processes. Indeed, it takes into account rainfall and the maximum infiltration capacity (S), which depends on the nature of the soil (lithology), vegetation and soil moisture content. In the current study, the basin surface and a regional parameter (a) were introduced in order to calibrate the model. This production function was implemented by supplying different values for the parameter (S). The values (n+1) were obtained by increasing the previous value (n) by 10 %. We evaluated the different values of (S) in the same way to obtain the last value (i). We calculated for these different values of the parameter (S) the square of the difference between the measured and estimated discharges for each year by measuring the discharge at different stations. For each station, we calculated the sum of these values for all the years and we retained the value of (S) that gave the minimal value. The results demonstrated that the values of (S) obtained were not significant because they tend to the infinite. For this reason, (S) was considered as a constant. In order to improve the model, we repeated the same operation, but instead of (S), we used the parameter (a) and performed the same calculation. After calibration of the model the results gave a coefficient of determination of 0.75, which means that 75 % of the variance was explained by the mean rainfall, the surface and the parameter (a).To explain the parameter (a), we calculated the correlation between its value at each station with the corresponding geology. This latter variable was characterized by the average storage capacity, which corresponds to the weighted average of the surfaces of the basin assigned to each permeability category (TOUAZI, 2001). The results demonstrated a coefficient of determination of 0.1. The correlation with the topographical relief was not necessary because it was taken into account in the cartography of the rainfall. We then proceeded to the cartography of the parameter (a). The results demonstrated an east-west gradient that was constant and a north-south gradient that decreased from north to south. With the digital elevation model, we used a geographical information system to deduce the slopes. For each basin, the average slope was calculated by taking the average of the values of the slopes of all the pixels that constituted the individual basin. The correlation between slopes and corresponding values of the parameter (a) gave a coefficient of correlation of 0.6.The results obtained by this model after calibration gave a coefficient of determination of 0.75, which means that 75% of the variance was explained by the mean rainfall, the surface and a coefficient (a), which corresponds to the average slope of the drainage basins

Characterization of the Hamra sheep breed in western Algeria

editorial reviewedThe present work is a part of a National Research Project (PNR Algeria 2022) dedicated to the development of the Hamra sheep breed in his cradle western Algeria. The aim of this study is to characterize the morphology, growth and reproductive performance of this ovine breed. A sample of 15 rams and 30 ewes were used for the morphological characterization versus a total of 1,328 head for the growth and reproduction performance carried out at the technical livestock institute in Saida area located in the western Algeria. Hamra sheep breed is small compared to other Algerian breeds. It has a dark brown (mahogany) head and legs, a blackish-blue tongue, white wool, spiral horns, and a fine, medium-length tail. Total body length is 124.5 cm for males and 110.5 cm for females, with a trunk length of 78.6 cm for males and 67.7 cm for females. Depth, width and circumference of chest are respectively 40.3 cm; 30 cm; 116.4 cm for males, and 34.2 cm; 22 cm; 99.8 cm for females. Growth monitoring showed an average birth weight of 3 to 3.6kg, depending on sex (male or female) and litter size (single or double). Live weights reached an average of 17.9kg for males and 16.2kg for females at 90th day of age. The ewes' reproductive performances are as follows: 82.2% for fertility, 97% for fecundity and 118% for prolificacy at birth and weaning. In conclusion, the Hamra breed has shown promise performances in terms of growth, but its butchering potential needs more assessments. Further studies are required to establish a conservation strategy becoming urgent by the uncontrolled introduction of genetics from other sheep breeds.PNR- Algérie12. Responsible consumption and productio

Effect of the essential oil of Rosmarinus officinalis (L.) on rooster sperm motility during 4°C short-term storage

Aim : This study aimed to investigate the protective effect of Rosmarinus officinalis (L.) essential oil on rooster sperm motility during 4°C short-term storage. Materials and Methods : R. officinalis essential oil was analyzed using gas chromato graphy coupled to mass spectrometry to identify the active components. 10 of 45-week-old Hubbard commercial broilers were subjected to biweekly semen collections during 3 weeks. At each collection, sperm was pooled and divided into four aliquots and then diluted with Tris extender supplemented with 870, 87, or 8.7 μg/ml of R. officinalis essential oil, identified as treatments R, R5, and R10, respectively. Tris-based extender without any supplementation was considered as a control group. Diluted sperm was then stored at 4°C in the refrigerator and analyzed at 0, 6, 24, and 48 h using a computer-assisted sperm analyzer. Different semen parameters were measured including total motility, progressive motility, gametes velocities (straight line velocity [VSL], curvilinear velocity [VCL], and average path velocity [VAP]), amplitude of the lateral head displacement [ALH], and beat- cross frequency [BCF]. Results : The phytochemical analysis of R. officinalis essential oil revealed the presence of 25 active components including seven major molecules: Camphor (18.88%), camphene (5.17%), 1,8-cineole (7.85%), β-thujene (13.66%), α-thujene (4.87%), chrysanthenone (12.05%), and β-cubenene (7.97%). The results showed a beneficial effect of R. officinalis essential oil on sperm cells motility, particularly when using the lowest concentrations, 8.7 and 87 μg/ml. Progressive motility and gametes velocities (VCL, VSL, and VAP), materializing the quality of gametes motility, showed highly statistically significant values (p<0.01) in 8.7 and 87 μg/ml treatments, especially from 6 h of storage at 4°C. Conversely, the highest concentration (870 μg/ml) showed harmful effects with a total spermicidal activity after 24 h of storage. Conclusion : The current results revealed the positive impact of R. officinalis essential oil on rooster sperm at 4°C short-term storage probably through fighting against oxidative stress and cold shock damages

The electrochemical behavior of zn-mn alloy coating in carbonated concrete solution

In order to improve the protective performance of Zn coating on reinforcing steel in concrete, the electrochemical deposition of Zn-Mn coatings was conducted on steel surface. The morphology, chemical and phase compositions of Zn-Mn coatings obtained from sulfate-citrate bath were investigated in the first part of paper. In the second part, the obtained deposits were tested in solution simulating carbonated concrete, consisting of NaHCO3 and Na2CO3. Data obtained from Tafel analysis showed higher corrosion resistance for Zn-Mn alloy deposits obtained at -1700 and -1800 mV versus SCE, when compared to pure Zn deposit. Impedance spectroscopy investigations revealed that the total impedance of Zn-Mn coatings increased steadily with time, and was significantly higher as compared to pure Zn after 24 h in corrosion solution. On the contrary, for pure Zn, the impedance increased in the first 12 h, and then decreased during prolonged exposure time, which can be explained by rapid growth of nonprotective white rust and the degradation of zinc coating, as was confirmed by optical microscope after 24 h of immersion in carbonated concrete pore solution

Elect: An Inconsistency Handling Approach for Partially Preordered Lightweight Ontologies

International audienc

A crash course on generalized possibilistic logic

International audienceThis paper proposes a concise overview of the role of possibility theory in logical approaches to reasoning under uncertainty. It shows that three traditions of reasoning under or about uncertainty (set-functions, epistemic logic and three-valued logics) can be reconciled in the setting of possibility theory. We offer a brief presentation of basic possibilistic logic, and of its generalisation that comes close to a modal logic albeit with simpler more natural epistemic semantics. Past applications to various reasoning tasks are surveyed, and future lines of research are also outlined