Stochastic representation of the Reynolds transport theorem: revisiting large-scale modeling

We explore the potential of a formulation of the Navier-Stokes equations incorporating a random description of the small-scale velocity component. This model, established from a version of the Reynolds transport theorem adapted to a stochastic representation of the flow, gives rise to a large-scale description of the flow dynamics in which emerges an anisotropic subgrid tensor, reminiscent to the Reynolds stress tensor, together with a drift correction due to an inhomogeneous turbulence. The corresponding subgrid model, which depends on the small scales velocity variance, generalizes the Boussinesq eddy viscosity assumption. However, it is not anymore obtained from an analogy with molecular dissipation but ensues rigorously from the random modeling of the flow. This principle allows us to propose several subgrid models defined directly on the resolved flow component. We assess and compare numerically those models on a standard Green-Taylor vortex flow at Reynolds 1600. The numerical simulations, carried out with an accurate divergence-free scheme, outperform classical large-eddies formulations and provides a simple demonstration of the pertinence of the proposed large-scale modeling

AMADEOS outil de création de scénarii réalistes dans les réseaux ad hoc mobiles

Mobile Ad hoc Networks (MANETs) have become a lively field in the past few years. This thesis presents a tool to generate realistic mobility traces for MANET simulations. A new java-based mobility module named AMADEOS (A dvanced M obility Model in AD hoc NE twO rkS ) was developed as an extension for the CANUmobisim framework, a powerful mobility trace generator. AMADEOS makes it easy and fast to generate realistic mobility. It allows the editing of spatial environments with polygonal obstacles to be used within simulations. It also allows visualizing an animation of the generated mobility traces. To model mobility for simulation environments with obstacles, a new mobility model was created. A new propagation model based on ray tracing was also implemented as part of AMADEOS. This propagation model takes into account the obstacles in the environment. Our study ends with a re-evaluation of the well-known AODV routing protocol in some realistic scenarios. The results have shown up significant changes in protocol performance in such realistic scenarios."--résumé abrégé par UMI

Kinetic and thermodynamic parameters for thermal denaturation of ovine milk lactoferrin determined by its loss of immunoreactivity

Lactoferrin is a protein with important biological functions that can be obtained from milk and by-products derived from the dairy industry, such as whey. Although bovine lactoferrin has been extensively studied, ovine lactoferrin is not quite as well known. In the present study, the effect of several heat treatments in 3 different media, over a temperature range from 66 to 75°C, has been studied on lactoferrin isolated from sheep milk. Denaturation of lactoferrin was determined by measuring its immunoreactivity with specific polyclonal antibodies. Kinetic and thermodynamic parameters obtained indicate that lactoferrin denatures by heat more rapidly in whey than in phosphate buffer or milk. The value of activation energy found for the denaturation process of lactoferrin when treated in whey is higher (390 kJ/mol) than that obtained in milk (194 kJ/mol) or phosphate buffer (179 kJ/mol). This indicates that a great amount of energy is necessary to start denaturation of ovine lactoferrin, probably due to the interaction of this protein with other whey proteins. The changes in the hydrophobicity of lactoferrin after heat treatments were determined by fluorescence measurement using acrylamide. The decrease in the hydrophobicity constant was very small for the treatments from 66 to 75°C, up to 20 min, which indicates that lactoferrin conformation did not experienced a greatchange. The results obtained in this study permit the prediction of behavior of ovine lactoferrin under several heat treatments and show that high-temperature, short-time pasteurization (72°C, 15 s) does not cause loss of its immunoreactivity and, consequently, would not affect its conformation and biological activity

Antibacterial activity of bovine milk lactoferrin on the emerging foodborne pathogen Cronobacter sakazakii: Effect of media and heat treatment

Cronobacter sakazakii is a pathogen transmitted by food, with high osmotic resistance and tolerance to desiccation, which affects mainly to newborns, infants and immunocompromised adults. C. sakazakii infection in infants has been associated with consumption of powdered milk. The purpose of this study was to evaluate the antibacterial activity of native and iron-saturated bovine lactoferrin (bLF) (from 0.5 to 5 mg/ml) on non-desiccated and desiccated C. sakazakii (104 CFU/ml) in different media (phosphate buffer, bovine skim milk and whey). In general, native bLF was the only effective form that inhibited growth of C. sakazakii in all media, its activity increasing with concentration and time of incubation. These results suggest that the antibacterial effect of bLF on C. sakazakii is mainly due to iron sequestration. However, iron-saturated bLF showed some effect by reducing the viability of C. sakazakii in whey. There has not been observed an increased sensitivity of desiccated bacteria to native bLF in phosphate buffer. However, although the antibacterial activity of native bLF against non-desiccated C. sakazakii was drastically reduced in milk or whey compared to phosphate buffer, there was a certain activity when it was assayed against desiccated cells in those media. The effect of some heat treatments on the antibacterial activity of native bLF was evaluated and only those of 72 °C for 15 s, 85 °C for 15 s, and 63 °C for 30 min maintained its whole activity

Are millet and sorghum good alternatives to maize in layer’s feeds in Niger, West Africa?

Niger is one of the West African country producing pearl millet (Pennisetum glaucum, Setaria italica) and sorghum (Sorghum bicolor). While pearl millet and sorghum are for human consumption, corn is imported and its high production costs are the main constraint to poultry production in Niger (Issa et al. 2015) As feed is the major input in poultry production and ever increasing cost and scarcity of feedstuffs are the major constraints in poultry production (Sheikh et al. 2016). A strong increasing trend and a high variation of the prices of cereals grains have spurred interest in using other feed ingredients produced in large scale (Ravindran 2013). Although possible alternatives for corn substitution by sorghum in poultry diet has been extensively studied in India, US, and West Africa (Parthasarathy et al. 2005, Issa 2009, Kawari et al. 2011, Bulus et al. 2014, Yunus et al. 2015). However, pearl millet, the cereal grain produced and used primarily as a human food in Niger, is little tested as poultry feed ingredient. Thus, the objective of this study was to evaluate performance, egg quality and egg cost in layers fed isocalorific and isonitrogenous diets in which corn is replaced by pearl millet or sorghum up to 50%..

Use of sorghum on stepwise substitution of maize in broiler feeds in Niger

With an objective to demonstrate the merits of diets based on locally produced non-tannin sorghums as against Maize a total of 240 1-day-old broiler chicks Early bird strain were randomly allocated to 20 pens (12 birds per pen) with four pens per treatment and five treatments, at the Maradi Government poultry farm in Niger for a period of 12weeks. Birds were allowed to consume feed and water on an ad-libitum basis. The treatments diets were: i) Maize -based, ii) 75% Maize+25% Sorghum, iii) 50% Maize+50% Sorghum, iv) 25% Maize + 75% Sorghum, and v) Sorghum. Birds consumed water and feed on an ad-libitum basis with body weights recorded on day 0, 21, and 49. At the end of the experiment, 5 birds per pen were randomly chosen and slaughtered for carcass analysis. All growth and carcass data were analyzed as a randomized complete block design using the Proc Mixed procedure of R. Live weight was used as a covariate during carcass data analysis. Bodyweight means of 41g at d-0 and 1419 g at d-49 were similar (P = 0.17) for birds fed on all five treatments. Mean Gain/feed (G/F) ratios were similar with a mean of 540 g/kg to d-49. Birds fed Maize based, sorghum-based or Maize-sorghum-based diets had similar growth performance and carcass characteristics. Thus, tannin free sorghum had nutritional value comparable to that of Maize, and in West Africa local sorghum is a good alternative for poultry feeds when grains price are similar

Ingestions Alimentaires Et Performances De Production Et De Reproduction Des Lapines (Oryctolagus Cuniculus) Gestantes Nourries Avec Des Aliments Contenant Des Feuilles De Neem (Azadirachta Indica)

This study was conducted as part of a series of experiments on the use of dried leaves for the production of complete rabbit feed. For this purpose, 120 female rabbits, distributed in 4 batches (N0, N5, N10 and N15) with the same number (30) and homogeneous average weights (2595 g to 2708.7 g) were followed before and during pregnancy. Each of the 4 lot were composed, in the same proportion, of nulliparous and multiparous females. Those animals were subjected to four Azadirachta indica leaves based foods in different proportions: N0: 0%; N5: 5%; N10: 10% and N15: 15%. Our data shows that the gestation rates were as follows for the four lots: N0 (90%), N5 (80%) and N10 (90%) and N15 (76.67%). Except a single female from lot N10, all females were pregnant and gave birth. No significant difference (P> 0.05) was found between the mean of total daily consumptions among the pregnant rabbits of the four batches that ranged from 169.40 to 198.31 g / d. The average litters of the batches N0 (5.33 rabbits / mother), N5 (6.5 rabbits / mother) and N10 (5.61 rabbits / mother) were similar (P> 0.05) but higher (P 0.05). On the other hand, no difference (P> 0.05) was observed between the average weights of the rabbits of the control batch N0 (59.06 g) and those of N5 and N15

Impact de l’usage des gants médicaux sur l’observance de l’hygiène des mains au cours des soins au Centre Hospitalier et Universitaire du Point G de Bamako

Objectif : Évaluer l'impact de l'usage des gants médicaux sur l'observance de l'hygiène des mains et promouvoir leur usage approprié. Matériel et Méthodes: Il s’agissait d’une étude interventionnelle avec une évaluation avant et après intervention. Sa mise en œuvre a été réalisée entre avril 2010 et octobre 2011 au Centre Hospitalier et Universitaire du Point G. Le recueil du consentement éclairé et les observations ont été effectués auprès du personnel soignant ayant un contact direct avec les patients avant et après intervention. Ces observations ont été discrètes mais ouvertes, menées auprès des soignants préalablement informés du but et du programme des activités. Résultats : Au total, 143 fiches de consentement éclairé ont été retournées sur une prévision de 274 fiches, soit 52,19%. Les observations ont donné un taux d’observance globale de 52,05% avant intervention contre 42,97% après intervention (p = 0,0017). Le taux global de port de gants était de 23,30% et 27,20% respectivement avant et après intervention (p = 0,12). Conclusion : Les résultats des deux évaluations avant et après intervention ont montré une amélioration du taux global de port des gants qui n’était pas significative mais sans impact sur l’observance de l’hygiène des mains

Cholécystectomies Laparoscopiques Pour Cholécystite Aigue Lithiasique Versus Lithiase Vésiculaire Symptomatique

Introduction: The aim of this work was to highlight the therapeutic and prognostic difficulties between a laparoscopic cholecystectomy for acute gallstone cholecystitis (CAL) and uncomplicated symptomatic vesicular lithiasis (LVS) as well as the reasons for conversion to laparotomy. Patients and Methods: This was a prospective comparative and analytic study over 18 months. Patients admitted and operated for CAL or LVS in the A Surgery Department of the National Hospital of Niamey (HNN) were included. Results: The study involved 61 patients divided into two groups. Group 1 (30 patients) corresponding to patients operated for CAL, group 2 (31 patients) corresponding to patients operated for LVS. Laparoscopic cholecystectomy accounted for 61% of all cholecystectomies performed and 1.45% of surgical activity during the same period. The average age in group 1 was 43.7 years with extremes of 14 and 61 years. In group 2, the average age was 38.9 years with extremes ranging from 12 to 55 years. Women were predominantly represented with 63.3% and 96.7% respectively for groups 1 and 2. Patients were overweight in 9 cases for group 1 (30% of cases) and 12 cases in group 2 (38%), 7% of cases). Hepatic colic was the main sign of appeal in all patients in both groups. In group 1; 26 out of 30 cases or 86.7% of cases had leukocytosis, whereas in group 2, leukocytosis was normal in 30 cases, ie 96.8% of cases. Accessibility of the vesicle was difficult in 73.3% of cases in group 1 against 22.6% of cases in group 2. The vesicle was distended and necrotic in groups 1 in 76.7% and 10 respectively. % of cases. On the other hand, in 25.8% of cases, the vesicle was distended and without any necrosis in group 2. The rate of conversion to laparotomy was 6.55% (4 cases) and exclusively concerned group 1. Operative follow-up immediate outcomes were simple in 98.34% of cases. The complications involved 2 patients in group 1 (1.66% of the total), including parietal suppuration and biliary leakage. Mean operative time was 68.7 min in group 1 versus 41.6 min in group 2. Mean duration of hospitalization was 4.3 days with extremes between 2 and 10 days in group 1 versus1,7 days with extremes ranging from 1 to 7 days in group 2. Mortality was zero. Conclusion: In recent years, laparoscopic surgery has made remarkable progress in Niger. Laparoscopic cholecystectomy seems to be more difficult to perform with significant morbidity in the case of CAL than LVS. The risk of per and postoperative complications can be estimated from the clinical data (acute cholecystitis or symptomatic vesicular lithiasis) and the surgeon's experience. In a cholecystectomy that lasts more than 2 hours, the cumulative risk of complications is highe