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Flor yeast: new perspectives beyond wine aging
No full textPas de clé UTThe most important dogma in white-wine production is the preservation of the wine aroma and the limitation of the oxidative action of oxygen. In contrast, the aging of Sherry and Sherry-like wines is an aerobic process that depends on the oxidative activity of flor strains of Saccharomyces cerevisiae. Under depletion of nitrogen andfermentable carbon sources, these yeast produce aggregates of floating cells and form an air–liquid biofilm on the wine surface, which is also known as velum or flor. This behavior is due to genetic and metabolic peculiarities that differentiate flor yeast from other wine yeast. This review will focus first on the most updated data obtained through the analysis of flor yeast with -omic tools. Comparative genomics, proteomics, and metabolomics of flor and wine yeast strains are shedding new light on several features of these special yeast, and in particular, they have revealed the extent of proteome remodeling imposed by the biofilm life-style. Finally, new insights in terms of promotion and inhibition of biofilm formation through small molecules, amino acids, and di/tripeptides, and novel possibilities for the exploitation of biofilm immobilization within a fungal hyphae framework, will be discussed
Earning Management accross Publicly Traded and Privately Held French SMEs
No full textInternational audienceWe study how SMEs' financial choices affect the quality of accounting information in the French case. Using a sample of 925 firms observed over a nine year period, we compare earnings management practices between publicly traded SMEs (hereafter PUB_SMEs) and privately held ones (hereafter PRIV_SMEs). We find evidence, firstly, that access to the stock market encourages SMEs to manage earnings so as to appear to be performing better, secondly, that SMEs that do not benefit from such access use proprietary earnings management to appear less risky. The first appear to be more shareholder-oriented and the second more lender-oriented in their earnings management practices. PRIV_SMEs manipulate their net income to avoid small losses more frequently than PUB_SMEs. We also notice more pronounced income-smoothing behaviour among PRIV_SMEs than among PUB_SMEs. An analysis of discretionary accruals shows that PUB_SMEs use accruals to increase their apparent performance more intensively than PRIV_SMEs
Ab initio proposition of novel BCN3 hard material based on the intergrowth of wurtzite and pyrite-like motifs
No full textInternational audienceA novel hard material, orthorhombic BCN3 based on the intergrowth of non-centrosymmetric wurtzite CN+ and centrosymmetric pyrite BN2− motifs alike in fully characterized AlSiP3 ternary is proposed from calculations within DFT methodology. BCN3 is identified as a “nitride-dinitride” related with Zintl phases. The ground state structure exhibits significantly short interatomic distances: d(C-N) = 1.47 Å and d(N-N) = 1.43 Å as compared to d(Si-P) = 2.24 Å and d(P-P) = 2.18 Å in the phosphide, resulting into high magnitude bulk modulus obtained from E,V equation of state (EOS) with B0 = 371 GPa versus B0 = 97 GPa in the phosphide. The complete set of elastic constants complies with the mechanical stability conditions of the new system and equally produces high hardness magnitude (384 GPa). Ratio of bulk/shear modules of 0.85 characterizes a brittle material. Electronic band structures identify small indirect gap semi-conducting AlSiP3 and large band gap insulator BCN3 with direct gap ΓV-ΓC ∼ 4 eV
Physico-chemical and rheological properties of Lebanese kishk powder, a dried fermented milk-cereal mixture
No full textInternational audienceKishk is a traditional fermented milk-cereal mixture, widely consumed in Lebanon. Twenty Lebanese kishk powder samples were collected from artisanal producers in four Lebanese regions, in order to assess the effect of milk base and cereals on their physicochemical properties, functional and rheological properties. Milk type affected the fat content and color parameters of kishk samples. Multi-scale exploration of kishk microstructure revealed a complex network of macroconstituents (milk protein and wheat starch) embedded in a thick layer of fat. The mechanism of kishk rehydration was then exploited by analyzing the water sorption isotherms and observing the morphometric changes in the particles of this powder subjected to different relative humidities. From powder rheology measurements, kishk showed an intermediate flowability behavior and cohesiveness, associated to its high fat content as a binder between the particles
Validité de l’estimation des propriétés de rétention en eau de sols syriens à partir de fonctions et classes de pédotransfert développées pour des sols français
No full textInternational audienceTo address the lack of data on water retention properties of the Syrian soils, continuous and class pedotransfer functions (FPT and CPT, respectively) established for soils of the French territory were tested on soils originating from four regions of Syria. The samples were collected when the soil water content was near field capacity in winter. The composition of the samples and their water content at seven water potentials were determined. The prediction bias is calculated using the average prediction error (EMP), the precision using the standard error of prediction (ETP) and global quality of the prediction with the mean quadratic error (EQM). The results show that the best prediction was recorded with the FPT established with the water content at field capacity, in particular when they were established after stratification by texture class. This improvement in prediction after stratification by texture class is linked to the fact that the shape of the water retention curve varies with texture, a point of the curve not bringing the same information according to the class of texture. The values of the prediction bias and precision recorded with the FPT and CPT studied are close to those recorded when these FPT and CPT were tested on soils originating from the French territory. Finally, such results are encouraging and support the use pedotransfer.Afin de répondre au déficit de données relatives aux propriétés de rétention en eau des sols de Syrie, des fonctions continues et classes de pédotransfert (respectivement FPT et CPT) établies pour des sols du territoire français ont été testées sur un jeu de sols échantil-lonnés dans quatre régions de Syrie. Les échantillons ont été prélevés lorsque les sols se trouvaient en conditions hydriques proches de la capacité au champ (période hivernale). La composition des échantillons et leur teneur en eau à sept valeurs de potentiel ont été déterminées. Le biais de prédiction est calculé à l'aide de l'erreur moyenne de prédiction (EMP), la précision et la qualité globale de la prédiction ont été calculées à l'aide de l'écart type de prédiction (ETP) et l'erreur quadratique moyenne (EQM). Les résultats montrent que ce sont des FPT établies à partir de la teneur en eau à la capacité au champ qui conduisent à la prédiction de meilleure qualité, en particulier lorsqu'elles ont été établies après stratification par classe de texture. Cette amélioration de la prédiction après stratification par classe de texture serait liée au fait que la forme de la courbe de rétention en eau varie en fonction de la texture, un point de la courbe n'ayant par conséquent pas le même sens selon la classe de texture. Les valeurs des biais de prédiction et précisions enregistrées avec les FPT et CPT étudiées sont proches de celles enregistrées lorsque ces même FPT et CPT ont été testées sur des sols issus du territoire français. Enfin, de tels résultats sont encourageants et en faveur de l'utilisation de fonctions de pédotransfert établies pour des sols d'une zone pédoclimatique à des sols d'une autre zone pédoclimatique
Chemical composition and antimicrobial activity of Origanum libanoticum , Origanum ehrenbergii and Origanum syriacum growing wild in Lebanon
No full textInternational audienceThe essential oils (EOs) of the aerial parts of Origanum libanoticum and Origanum ehrenbergii, endemic to Lebanon, and Origanum syriacum, endemic to the Levantine, were obtained by distillation with a Clevenger apparatus. GC and GC/MS allowed identification of 96.4%, 93.5%, and 95.2% of their constituents, respectively. Carvacrol was the major component of both O. syriacum EO (79%) and O. ehrenbergii EO (60.8%). This compound was absent in O. libanoticum EO and the major compounds were β-caryophyllene (26.8%), caryophyllene oxide (22.6%), and germacrene D (17.2%). The assessment of their antimicrobial activity against Candida albicans and six pathogenic bacteria revealed that O. libanoticum EO was inactive, while O. syriacum and O. ehrenbergii showed moderate antimicrobial activity with minimal inhibitory concentrations varying from 400 to 1200 μg/ml. These results support the traditional use of these last two species in traditional herbal preparations in Lebanon
Report on the Medicinal Use of Eleven Lamiaceae Species in Lebanon and Rationalization of Their Antimicrobial Potential by Examination of the Chemical Composition and Antimicrobial Activity of Their Essential Oils
No full textInternational audienceMany Lamiaceae species are consumed in the Lebanese cuisine as food or condiment and are largely used in the traditional medicine of Lebanon to treat various diseases, including microbial infections. In this article we report the traditional medicinal uses of eleven Lamiaceae species: Coridothymus capitatus L., Lavandula stoechas L., Lavandula angustifolia Mill., Mentha spicata L. subsp. conden-sata, Origanum syriacum L., Rosmarinus officinalis, Salvia fruticosa Miller., Satureja cuneifolia Ten., Satureja thymbra L., Thymbra spicata L., and Vitex agnus-castus L. and study the chemical composition and antimicrobial activity of their essential oils (EOs). Our survey showed that Lamiaceae species are mainly used against gastrointestinal disorders and microbial infections. Chemical analysis of the EOs obtained from these plants allowed us to identify seventy-five compounds describing more than 90% of the relative composition of each EO. Essential oils with high amounts of thymol and carvacrol possessed the strongest antimicrobial activity. As expected, these two compounds demonstrated an interesting antifungal efficacy against the filamentous fungus T. rubrum. Our results confirmed that some of the Lamiaceae species used in Lebanon ethnopharmacological practices as antimicrobial agents do possess antibacterial and antifungal potential consistent with their use in alternative or complementary medicine
Isolation and characterization of santolinoidol, a bisabolene sesquiterpene from Achillea santolinoides subsp wilhelmsii (K. Koch) Greuter
No full textInternational audienceThe essential oil (EO) obtained by hydrodistillation of aerial parts of Lebanese Achillea santolinoides subsp wilhelmsii (K. Koch) Greuter was analyzed by GC and GC–MS. The identity of the second major compound was uncertain. Its structure was elucidated using 1D and 2D NMR spectroscopy as well as MS data. It appeared to be a new sesquiterpene with a 1-oxa-bicyclo[5,4,0]-undecane skeleton which was named santolinoidol. The EO revealed interesting antimicrobial potential particularly against Trichophyton species, Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA) with MIC values ranging from 16 to 128 μg/ml
Liquid–vapor equilibria of pure and aqueous solutions of diethylenetriamine or dipropylenetriamine
No full textInternational audienceVapor pressures of pure and aqueous diethylenetriamine (DETA) and dipropylenetriamine (DPTA) were measured by means of a static apparatus at temperatures between (283 and 363) K. The data were correlated with the Antoine equation and fitted to Redlich–Kister equation using Barker's method. Additionally, the NRTL, UNIQUAC models were used to correlate total pressures
Outside directors and firm performance across family generations in Lebanon
No full textInternational audienceThis paper investigates the relationship between the percentage of outside directors and financial performance in non-listed family firms while considering the generational effect. Using longitudinal data on 322 Lebanese firms covering the period 2008–2010, a regression analysis indicates that firm profitability depends upon the percentage of outside directors only in second and later generations. In first-generation family firms, the replacement of an inside director by an outsider has no significant impact on performance. In contrast, in the second and subsequent generations, outsiders can be used as an effective governance mechanism to reduce agency costs and thus enhance performance. Local entrepreneurs and regulators could build upon these results to implement better corporate governance practices in order to enrich the growth and prosperity of Lebanese family firms