Lactation Performance of Small Ruminants in the Maghreb Region

Maghreb areas are characterized by rainfall seasonality and scarcity resulting in a low fodder potential. In these arid and semiarid regions areas, small ruminant production is the main source of income of farmers living where sheep (Ovis aries) and goats (Capra hircus) are generally confronted with severe nutritional deficits during feed scarcity period which exacerbate disease and health troubles and consequently low performances. Interestingly and despite the importance of the milk performance to the dairy industry, very few works studied the potentialities of the mammary gland through the lactation period both in sheep and goats elevated in the Maghreb areas. Nevertheless, understanding the different mammary gland patterns throughout lactation is essential to improve dairy production and to reduce poverty and vulnerability in rural farming systems in these developing areas. The main objective of this review is to analyse the lactate processes as well as to underline the mammary gland morphological patterns, health and physiology traits and to evaluate milk potentialities of the main breeds of goats and sheep raised in Maghreb

Homogenization approach to filtration through a fibrous medium

We study the flow through fibrous media using homogenization techniques. The fiber network under study is the one already used by M. Briane in the context of heat conduction of biological tissues. We derive and justify the effective Darcy equation and the permeability tensor for such fibrous media. The theoretical results on the permeability are illustrated by some numerical simulations. Finally, the low solid fraction limit is considered. Applying results by G. Allaire to our setting, we justify rigorously the leading order term in the empirical formulas for the effective permeability used in engineering. The results are also confirmed by a direct numerical calculation of the permeability, in which the small diameter of the fibers requires high accuracy approximations

The Relevance of ATR-FTIR Spectroscopy in Semiconductor Photocatalysis

Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy has a high potential for investigating a wide range of samples and systems. In photocatalysis, various interfacial phenomena can be studied using this technique, including pH-dependent adsorption and photodegradation of probe molecules. The analysis of the processes occurring at the interface of thin particle films deposited on the surface of an ATR crystal, either in the liquid or the gas phase, is perhaps the best way to elucidate the mechanism of adsorption and heterogeneous photocatalytic reactions. This chapter summarizes the recent advances and applications of ATR-FTIR techniques in semiconductor photocatalysis. A brief outlook at some of the possible investigations in this area is provided and the different proposed adsorption and photocatalytic degradation mechanisms are discussed

Liquid Film Evaporation: Review and Modeling

Liquid film evaporation is encountered in various applications including in air humidifiers, in multiple effect distillers in thermal desalination, and in absorption cooling evaporators. It is associated with a falling pure, binary or multicomponent liquid film with associated complex and coupled heat and mass transfer processes. This chapter presents important fundamental aspects inherent to falling film evaporation in several geometrical configurations such as on horizontal tubes and inside inclined or vertical tubes or channels. The first part of the chapter concerns a review of recent works on this topic with emphasis on modeling and simulation features related to falling liquid films with heat and mass transfers. This document aims also to establish a frame for the modeling of the fluid flow with heat and mass transfer in the presence of evaporation. The main governing equations and the appropriate boundary and interfacial conditions corresponding to the fluid flow and associated heat and mass transfer and phase change are systematically presented and discussed for the case of falling film in a vertical channel with the presence of flowing gas mixture. Various simplifications of the governing equations and boundary and interfacial conditions have been proposed and justified. In particular, the formulation with extremely thin liquid film approximation is discussed

Governance and attractiveness of FDI: the case of Southern and Eastern Mediterranean countries

This article empirically examines the role of governance in attracting FDI for a sample of ten Southern and Eastern Mediterranean countries over a 15-year period. We have approximated the attractiveness of FDI by governance through an endogenous variable called FDI in relation to GDP. The quality of these variables was tested by the positioning, dispersion and shape indicators and verified the normality of these variables by the Jarque-Berra test and the quality of linear adjustment of each variable with respect to its mean. The empirical validation of the impact of good governance in the attraction of FDI was carried out using the static Panel technique and based on the assumption of the absence of a stationarity problem for the explanatory variables of our model. Homogeneity-heterogeneity tests were used to specify the reference model and model the role of governance in the attraction of FDI by a panel with individual effects. The estimation of this model by the Within and GLS procedures yielded significant results

Bioclimatic approach of passive cooling techniques for the design of buildings in southern Algeria

The bioclimatic approach looks into the opportunities for building conception under the local climatic conditions. The first bioclimatic chart has been developed by Olgyay which combines temperature with relative humidity to characterize the comfort zone. It is founded on outside climate conditions to identify attenuation measures such as solar radiation, wind speed, or shading to reach comfortable inside conditions. Givoni created also a bioclimatic chart founded on inside conditions using the physical and thermal properties of air. Bioclimatic approach strategies contribute to decreasing the building energy loads and increasing thermal comfort for its residents over the year. The principal aim of this research is to evaluate a bioclimatic approach to passive cooling for building design in Algeria's South using Givoni's Bioclimatic chart and Olgyay's Bioclimatic chart. Climate data of various locations (Ouargla, Ghardaia, and El Oued) within this area were collected and analyzed. Furthermore, an overview of appropriated conception strategies for the hot season for each zone is developed. The results show that the maximum average temperature from June to August at around 43.1°C. After applying passive cooling strategies, the temperature indoor can be decreased from about 26.1 to 31.4°C, which can be described as being in the comfort zone for the three studied locations. Finally, these findings can contribute to understanding the thermal behavior of residential buildings and offer guidelines to develop a convenient concept of what the building composition should look like in arid and hot climates

Un modèle multiéchelle de transport de colloïdes avec diffusion dégénérée anisotrope

Projet M3NNous considérons un système faiblement couplé d'équations semi-linéaires de type hyperbolique-parabolique avec une diffusion anisotrope dégénérée. Ce système se rencontre dans la modélisation de l'évolution d'un traceur chimique ou biologique dans un milieu poreux. Nous étudions ce problème avec une théorie L^1, puis nous établissons la limite quand la constante de réaction devient grande. Nous montrons que le système converge vers une équation non linéaire parabolique-hyperbolique qui généralise le problème de Stefan. Deux spécificités de cet article sont (i) le traitement de données initiales «mal préparées» et (ii) l'unicité des solutions entropiques basée sur une inégalité d'entropie précise

Antioxidant activity of ethanolic extract of inflorescence of Ormenis Africana in vitro and in cell cultures

<p>Abstract</p> <p>Background</p> <p>The antioxidant potency of the hydroethanolic extract of <it>Ormenis Africana </it>(HEOA), Asteraceae was evaluated with regards to total polyphenol, flavonoid and anthocyanins content. Antioxidant activity has been assessed chemically and biologically. First, the free radical scavenging ability of HEOA was evaluated using two commonly in vitro tests: ABTS and DPPH radicals. Then, the protection effect of this extract against oxidative stress was conducted in HeLa cells treated with Fe²⁺or H₂O_2.Oxidative stress was evaluated by measuring the lipid peroxidation levels (TBARs and DC) and the antioxidant enzymes activities (catalase and Superoxide dismutase). Cytotoxic effect of HEOA was prealably determined against HeLa cell line by MTT assay.</p> <p>Results</p> <p>HEOA contain considerable levels of antioxidant compound as evidenced by high amount of polyphenols (312.07 mg GAE/g dray matter), flavonoids (73.72 ± 1.98 mg QE/g dray matterl) and anthocyanins (0.28 ± 0.09 mg Cy-3-glu E/g dray matter). DPPH and ABTS assays showed a high antioxidant activity (IC₅₀= 24 μg/ml; TEAC = 2.137 mM) which was comparable to BHT.</p> <p>In biological system, HEOA exhibited a 50% cytotoxic concentration evaluated as 16.52 μg/ml. Incubation of HeLa cell line with no cytotoxic concentrations resulted in a remarkable protection from oxidative stress induced by Fe²⁺or H₂O₂which was evidenced by a decrease of MDA and CD levels as well as a diminution of antioxidant enzymes activities (Catalase and SOD) as compared to cells treated with Fe²⁺or H₂O₂alone.</p> <p>Conclusion</p> <p>The hydroethanolic extract of <it>O. Africana </it>could thus be considered as a source of potential antioxidants. The results of this study will promote the reasonable usage of this plant in food and pharmacy industries as well as in alternative medicine and natural therapy.</p

Elaboration et caractérisation de mousses métalliques à base de Sn-Pb

Cette étude est consacrée à l'élaboration par le procédé d'infiltration de l'alliage liquide et a la caractérisation (comportement mécanique et microstructure) de mousses métalliques à base d'Etain-Plomb de différentes densités relatives et taille de pores. Des essais de compression uniaxiale à l'ambiante ont été réalisés afin d'étudier l'influence de la taille de cellule et de la densité relative sur le comportement en compression et de situer ces relations dans le cadre des théories. Une caractérisation à l'échelle microscopique (métallographie et dureté) à été réalisée afin de relier les caractéristiques morphologiques et mécaniques des phases présentes dans les brins, les paramètres du procédé d'élaboration et le comportement mécanique macroscopique

Study of a Natural Mutant SHV-Type -Lactamase, SHV-104, from Klebsiella pneumoniae

Klebsiella pneumoniae ML2011, a multiresistant isolate, was isolated from the Military Hospital of Tunis (Tunisia). The determination of the minimal inhibitory concentrations exhibited by K. pneumoniae ML2011 was performed by Etest. The crude extract of the isolates contains four different -lactamases with pI 5.5, 7.3, 7.6, and 8.6. Only the -lactamases with pI 7.3 and pI 8.6 were transferred by transformation and conjugation experiment. Molecular characterization of these genes was performed by PCR and sequencing. The chromosomal -lactamases are TEM (pI 5.5) and SHV-1 (7.6). CTX-M-28 (pI 8.6) and the novel variant of SHV named SHV-104 (pI 7.3) were encoded by bla gene located on a 50 kb highly conjugative plasmid. The SHV-104 -lactamase was produced in E. coli and purified. Its profile of activity was determined. Compared to SHV-1, SHV-104 contains one mutation, R202S. Their kinetic parameters were similar except for cefotaxime. The analysis of the predicted structure of SHV-104 indicated that the R202S mutation suppresses a salt bridge present in SHV-1. Therefore, the overall flexibility of the protein increased and might improve the hydrolysis of cefotaxime. We can conclude that the multiresistant phenotype of K. pneumoniae ML2011 strain is mainly linked to the production of CTX-M-28 since SHV-104 possesses a narrow spectrum of activity