Error estimates for Stokes problem with Tresca friction condition

In this work we propose and study a three field mixed formulation for solving the Stokes problem with Tresca-type non-linear boundary conditions. Two Lagrange multipliers are used to enforce div(u)=0 constraint and to regularize the energy functional. The resulting problem is discretised using "P1 bubble/P1-P1" finite elements. Error estimates are derived and several numerical studies are achieved

Contribution to the study of adaptation of durum wheat cultivars (Triticum durum Desf.) to organic farming: grain yield,stability and technological and nutritional quality

The objective of this study is to investigate the potential of different durum wheat varieties that could be adapted for organic farming. In this context, four experimental years studies (2001, 2002, 2003 and 2004) were carried out in order to assess fourteen durum wheat varieties including nine old and five improved varieties conducted under organic and conventional cultivation methods and in two cereal growing locations : Kef "Boulifa" : low semi-arid and Bousalem “El Kodia” : higher semi-arid. Studied parameters included (i) grain yield, (ii) yield stability using coefficient of variation, linear regression coefficient, deviations from regression, ecovalence of Wricke, ecovalence of Shukla, ecovalence of Plaisted and Peterson and superiority index of Lin and Binns, (iii) technological and nutritional quality of the whole grain, dry matter, specific weight, proteins, amino acids, mineral content, gluten, amylasic activity and baking strength. Results of the agronomic traits indicated that grain yield is on the average lower under organic cultivation compared to conventional methods (23.2 and 29.8 qx/ha SEM=0.18 qx/ha respectively). However, varieties performance under this environment changed in dry year as was the case in 2001. Data analysis indicated high production potential of some varieties such as Khiar, Ben Bechir and INRAT69 (24.7, 24.6 and 24.4 qx/ha respectively) under organic farming method. INRAT69 was found stable for grain yield under organic farming with low coefficient of variation (33 %) and a linear regression coefficient close to one (bi=0.94). Khiar and Ben Bechir varieties, identified for organic cultivation, were unstable. Results of the technological and nutritional quality were influenced by the cultivation method. The organic method affected positively specific grain weight (80.3 vs 78.3 kg/hl, SEM=0.03 kg/hl), proline contents (1.154 vs 1.146 g/100g of FM) and cystéine (0.216 vs 0.186 g/100g of FM), gluten index which is responsible for the rheological properties of dough (64.73 vs 61.46 %) and amylasic activity (406.7 vs 442.6 s, SEM=1.78 s). Contrary to the organic method, grain protein content is better in the conventional method (13.9 vs 13.5 %/MF, ESM=0.008 %/MF). Organic cultivation of INRAT69 variety was found to be associated with high nutritional and technological quality parameters such us grain weight, dry matter, total amino acids content, gluten index and amylasic activity. Regardless of the cultivation method, results showed that old varieties Badri, Jnah Khortifa and Hamira have high protein and total amino acids content (> 16 %/FM and > 14.5 g/100g FM, respectively). These varieties should be considered by breeders in selection and breeding programs of durum wheat for organic farming. Based on these results, only INRAT69 variety could be potentially used in organic agriculture not only because its stable yield, but also because of its higher technological and nutritional quality. This variety could also be adapted for manufacturing organic pasta and couscous

Corrosion Inhibition of AISI 316L and Modified-AISI 630 Stainless Steel by the New Organic Inhibitor [(CH3)2N]3PSe in Chloride Media:Electrochemical and Physical Study

We evaluate the effect of the Tris-dimethylaminoselenophosphoramide (SeAP)on the corrosion inhibition of modified-AISI 630 and AISI 316L stainless steel (SS) in 3 wt. % NaCl. The electrochemical behaviors of tested SS samples are investigated before and after adding the Seep into the chloride media by potentiodynamic polarization technique. The adsorption of SeAP onto both SS surfaces is verified by global discharge optical emission spectroscopy (GDOES).  SeAP is found to be a good inhibitor for SS corrosion, especially when added at a concentration of 0.5 wt. %

Vers une nouvelle stratégie d'estimation conjointe des paramètres matériaux et de l'état des structures par assimilation de données et recalage

Dans cet article, on propose une nouvelle stratégie pour une estimation simultanée de l'état d'une structure et les paramètres des lois de comportement des matériaux qui la constituent. Celle-ci se résume en deux étapes. La première est une identification variationnelle déterministe des paramètres matériaux, basée sur une fonctionnelle d'erreur en énergie. A l'issue de cette étape, on utilise les paramètres optimaux identifiés ainsi que le Hessien de la fonctionnelle en ces points pour bâtir la seconde étape, probabiliste, utilisant les techniques d'assimilation variationnelle et traitant les données incertaines qu'on dispose. Celle-ci permet conjointement une correction des paramètres matériaux identifiés et une estimation de l'état du système

PERFORMANCE OF DURUM WHEAT VARIETIES (TRITICUM DURUM Desf.) UNDER CONVENTIONAL AND ORGANIC AGRICULTURE

Field experiments were conducted for four years to determine the effects of organic and conventional systems and fourteen varieties (nine old and five improved) on growth, yield and quality of durum wheat crop. The experiments conducted at two sites (low semi-arid and higher semi-arid) were laid out in a split-plot design with four replicates. Studied parameters included (i) grain yield, (ii) technological and nutritional quality of the whole grain, dry matter, specific weight, proteins, amino acids, mineral content, gluten and baking strength. Results of the agronomic traits indicated that grain yield is on the average lower under organic cultivation compared to conventional methods (2.32 and 2.98 t/ha SEM=0.18 qx/ha respectively). However, varieties performance under this environment changed in dry year. Data analysis indicated high production potential of some varieties such as Khiar, Ben Bechir and INRAT69 (2.47, 2.46 and 2.44 t/ha respectively) under organic farming method. INRAT69 was found stable for grain yield under organic farming with low coefficient of variation (33 %) and a linear regression coefficient close to one (bi=0.94). Khiar and Ben Bechir varieties, identified for organic cultivation, were unstable. Results of the technological and nutritional quality were influenced by the cultivation method. The organic method affected positively proline contents (1.154 vs 1.146 g/100g of FM) and cystéine (0.216 vs 0.186 g/100g of FM) and gluten index which is responsible for the rheological properties of dough (64.73 vs 61.46 %). Contrary to the organic method, grain protein content is better in the conventional method (13.9 vs 13.5 %/MF, ESM=0.008 %/MF). Organic cultivation of INRAT69 variety was found to be associated with high nutritional and technological quality parameters such us grain weight, dry matter, total amino acids content and gluten index. Regardless of the cultivation method, results showed that old varieties Badri, Jnah Khortifa and Hamira have high protein and total amino acids content (> 16 %/FM and > 14.5 g/100g FM, respectively). These varieties should be considered by breeders in selection and breeding programs of durum wheat for organic farming. Based on these results, only INRAT69 variety could be potentially used in organic agriculture not only because its stable yield, but also because of its higher technological and nutritional quality. This variety could also be adapted for manufacturing organic pasta and couscous

Huge desmoid tumor of the anterior abdominal wall mimicking an intraabdominal mass in a postpartum woman: a case report

Desmoid tumors are benign neoplasms that most often arise from muscle aponeurosis and have been associated with both trauma and pregnancy. The etiology of desmoids has not been determined. We report the case of anterior abdominal wall desmoid tumor in a female patient with previous history of cesarean section. Preoperative ultrasound and computed tomography demonstrated a large mass mimicking a large hematoma or an intraabdominal mass. The tumor was removed by wide excision with safe margins. The abdominal wall defect was reconstructed with polypropylene mesh. Subsequent histology revealed a desmoid tumor. Desmoid tumors in females are often associated with pregnancy or occur post-partum. The reasons behind this association are unclear. The most common sites are in the abdominal muscles.Pan African Medical Journal 2013; 14:5

Characterization of Mediterranean durum wheat for resistance to Pyrenophora tritici-repentis

Tan spot (TS), caused by the fugus Pyrenophora tritici-repentis (Ptr), has gained significant importance in the last few years, thereby representing a threat to wheat production in all major wheat-growing regions, including Tunisia. In this context, we evaluated a Mediterranean collection of 549 durum wheat accessions under field conditions for resistance to Ptr over two cropping seasons in Jendouba (Tunisia), a hot spot for Ptr. The relative disease severities showed significant phenotypic variation from resistance to susceptibility. The correlation between disease scores over the two trials was significant, as 50% of the accessions maintained good levels of resistance (resistant–moderately resistant). Seedling-and adult-stage reactions were significantly correlated. The ANOVA analysis revealed that the genotype term is highly significant at the adult stage, thus emphasizing the high genetic variability of the tested accessions. Reaction-type comparison among and between countries revealed a high diversity of TS resistance. Plant height (PH) was negatively correlated to disease scores, indicating that PH might either have a significant effect on TS severity or that it can be potential disease escape traits. The evaluation of this collection allowed for the identification of potential diverse resistance sources to Ptr that can be incorporated in breeding programs

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century