The spontaneous fermentation of butter produces a highly fragrant product called smen. The short chain fatty acids (C4 to C10) have been traditionally considered the main aromas of this product but our work on the volatile fraction characterisation using SPME GC/MS showed that other products may also be important. Indeed, 183 different volatile compounds were detected belonging mainly to carboxylic acids, esters, ketones, nitrogen compounds and terpenes. However, only 19 compounds were common to more than 50% of the samples. These include short chain fatty acids (C4 to C10), their esters and short chain methylketones (C5 to C11). Despite their high levels in all samples, the amounts of C4 to C10 free fatty acids could not explain the differences in preparation and consumer appreciation of the samples. In contrast, the levels and nature of some methylketones and esters, particularly butanoic and hexanoic ethyl esters and 2-pentanone, seem to better reflect the effects of salt, thyme, acidity and consumer preferences.

Recently, various mathematical models have been proposed to model COVID-19 outbreak. These models are an effective tool to study the mechanisms of coronavirus spreading and to predict the future course of COVID-19 disease. They are also used to evaluate strategies to control this pandemic. Generally, SIR compartmental models are appropriate for understanding and predicting the dynamics of infectious diseases like COVID-19. The classical SIR model is initially introduced by Kermack and McKendrick (cf. (Anderson, R. M. 1991. “Discussion: the Kermack–McKendrick Epidemic Threshold Theorem.” Bulletin of Mathematical Biology 53 (1): 3–32; Kermack, W. O., and A. G. McKendrick. 1927. “A Contribution to the Mathematical Theory of Epidemics.” Proceedings of the Royal Society 115 (772): 700–21)) to describe the evolution of the susceptible, infected and recovered compartment. Focused on the impact of public policies designed to contain this pandemic, we develop a new nonlinear SIR epidemic problem modeling the spreading of coronavirus under the effect of a social distancing induced by the government measures to stop coronavirus spreading. To find the parameters adopted for each country (for e.g. Germany, Spain, Italy, France, Algeria and Morocco) we fit the proposed model with respect to the actual real data. We also evaluate the government measures in each country with respect to the evolution of the pandemic. Our numerical simulations can be used to provide an effective tool for predicting the spread of the disease.

du diagnostic épidémiologique et d'hygiène du milieu-Marrakech-Maroc.

No abstract

The major environmental factor that determines goiter prevalence is iodine status. However, other trace elements like selenium and zinc can influence the thyroid function. Hair samples (n = 68) were collected from goitrous and non-goitrous children aged 8-12 years living in the area of Al Haouz Marrakech-(Morocco). Trace element concentrations (Cr, Fe, Mg, Zn, Se, I) in hair were measured using flame atomic absorption spectroscopy, graphite furnace atomic absorption spectroscopy, and inductively coupled plasma mass spectrometry. Difference in the mean concentration of each trace element between groups was determined by ANOVA test. The mean concentration levels of I, Se, and Zn for goitrous children were lower and were similar to the mean concentrations reported in the literature for subjects with goiter. The regression results gave us a better model that revealed significant positive relations between thyroid volume and Zn contents and significant negative relation with I and Se. The overall findings of the present study revealed that the actual factors of thyroid gland volume increase are I and Se deficiency. This work could shed some light on the effects of trace elements-other than iodine-on the thyroid disorders.