Assessment of trace metal contamination in mangrove ecosystems from Senegal, West Africa.

International audienceThe inorganic contamination of sediment and harvested molluscs was investigated in the mangrove environment of Southern West Senegal. Trace metals were analysed in surface sediments, two bivalves (Arca senilis and Crassostera gasar) and three gastropods (Conus spp., Hexaplex duplex and Pugilina morio) collected from four stations: Dionewar, Niodor and Falia localised in the Saloum Delta, and Fadiouth from the Petite Côte. A geochemical normalisation approach by using aluminium allowed for discrimination of sediment contamination among sites. Indeed, Fadiouth appeared highly contaminated with Cd, Hg and Ni compared to the Saloum Delta. For all mangrove sites, trace metals exhibited significant higher concentrations (on a dry weight basis) in shellfish compared to sediments, excepted for Ni and Pb. The distribution pattern followed a similar global trend in molluscs regardless of the spatio-temporal variability, with the predominance of Zn (80% of total metals) followed by Cu and Cd. However, strong differences of metal bioavailability and bioaccumulation in biota were demonstrated, revealing the requirement of employing a suite of organism bioindicators to monitor metal contamination in mangrove ecosystems. From an ecotoxicological point of view, trace metal levels in sediments from the Petite Côte and the Sine-Saloum Estuary were below the effects range-low (ERL) threshold limit of the sediment quality guidelines for adverse biological effects (SQGs). On the opposite, some concerns about Cd contamination of edible shellfish from Southern West Senegal were highlighted, from both the safety point of view of local populations' health, and the chemical quality point of view of exported resources

Composting of sugar cane bagasse by Bacillus strains

Composting of sugar cane bagasse with Bacillus sp. CMAGI2 and Bacillus subtilis JCM 1465T strains was carried out during five months at horticultural center. Chemical, biochemical and microbial parameters were followed during this process. There was a difference between inoculated composts and non-inoculated compost. These bacterial additives allowed greater biodegradation compared to control compost. The inoculated composts were more degraded than the control compost with compost3 which presented the highest OM loss with 91.37%, compost1 with 90.15% and compost2 had 89.47% of OM loss. Control compost showed the lowest C/N ratio, however compost3 had the highest C/N ratio compared to compost1 and compost2. Microbiologically, Bacillus strains in compost1 and compost2 had probably inhibitory effect on microflora statistically if they were inoculated alone when the mixture of two strains (compost3) had no inhibitory effect on microflora during the composting process. The inoculated composts presented higher enzymatic activities than control compost, probably due to the presence of Bacillus strains.Key words: Sugar cane bagasse, composting, Bacillus sp.CMAGI2, Bacillus subtilis JCM 1465T

Circulating undercarboxylated osteocalcin and gingival crevicular fluid tumour necrosis factor-α in children.

International audienceOsteocalcin, a protein secreted by osteoblasts during bone formation, is negatively associated with adult periodontal disease. Little is known about this association in children. To examine the extent to which plasma undercarboxylated osteocalcin (ucOC) is associated with gingival crevicular fluid tumour necrosis factor-alpha (GCF TNF-α) - a potential marker of gingival inflammation - in children. We used data from the Quebec Adipose and Lifestyle InvesTigation in Youth cohort, an ongoing longitudinal study on the natural history of obesity among Caucasian children with a family history of obesity in Quebec, Canada. This cross-sectional analysis from the baseline visit includes 120 children aged 8-10 years. Plasma ucOC and GCF TNF-α levels were determined by enzyme-linked immunosorbent assay. Linear regression analyses, adjusting for age, gender, family income, sexual maturity stage, daily physical activity, obesity, and fasting glucose were conducted, with TNF-α level as the dependent variable. A 1-ng/ml increase in ucOC was associated with a 0.96% decrease (95% confidence interval (CI): -1.69, -0.23) in GCF TNF-α level. A negative association between a marker of bone formation and a marker of gingival inflammation was observed as early as childhood among Caucasian children with a family history of obesity

Metabolic syndrome and gingival inflammation in Caucasian children with a family history of obesity.

International audienceTo investigate whether metabolic syndrome (MetS) and its components are associated with gingival inflammation in children. This is a cross-sectional analysis from the baseline visit of the QUebec Adipose and Lifestyle InvesTigation in Youth cohort, an ongoing longitudinal study investigating the natural history of obesity in children of Quebec, Canada. The analytic sample includes 448 children aged 8-10 years, 39% of whom were overweight or obese. MetS was defined according to the International Diabetes Federation recommendations. Gingival inflammation was defined by the level of gingival crevicular fluid (GCF) tumour necrosis factor alpha (TNF-α) and the extent of gingival bleeding. Sex-specific linear regression analyses estimated the associations between MetS and gingival inflammation, adjusting for potential confounders. Twenty-five children had MetS. Boys with MetS compared to those without, had a 49.5% (p-value = 0.001) higher GCF TNF-α level and 13.7% (p-value = 0.033) more sites with gingival bleeding. Moreover, for three of the five components of MetS - waist circumference, fasting plasma triglycerides, systolic blood pressure - an increase was associated with increased GCF TNF-α level in boys. No such findings were seen in girls. An association between MetS and gingival inflammation was observed as early as in childhood, and may differ by sex

Estimation of k-Factor GIGARCH process: A Monte Carlo study

International audienceIn this paper, we discuss the parameter estimation for a k-factor generalized long memory processwith conditionally heteroskedastic noise. Two estimation methods are proposed. The first method is based on the conditional distribution of the process and the second is obtained as an extension of Whittle's estimation approach. For comparison purposes, Monte Carlo simulations are used to evaluate the finite sample performance of these estimation techniques, using four different conditional distribution functions