An efficient numerical method for shakedown analysis

The algorithm proposed in [9] for incremental elastoplasticity is extended and applied to shakedown analysis. Using the three field mixed finite element proposed in [22] a series of mathematical programming problems or steps, obtained from the application of the proximal point algorithm to the static shakedown theorem, are obtained. Each step is solved by an Equality Constrained Sequential Quadratic Programming (EC-SQP) tech- nique that allows a consistent linearization of the equations improving the computational efficiency

Prehistoric surveys in the Libyan Sahara

Sin resume

A mixed algorithm for incremental elastoplastic analysis

A new method for the incremental analysis of elastoplastic associated materials is presented. The method fully retains all the equations and variables of the problems at the same level and uses a sequential quadratic programming with equality constraints to solve in an efficient and robust fashion the elastoplastic step equations derived by means of a suitable mathematical programming formulation of the problem. The new proposal is compared with standard strain driven formulations which use a return mapping by closest point projection schemes. The numerical tests performed show a good performance and a great robustness of the proposed formulation also in the case of multi–surface elastoplasticity

Humans and Water in Desert “Refugium” Areas: Palynological Evidence of Climate Oscillations and Cultural Developments in Early and Mid-Holocene Saharan Edges

Saharan anthropic deposits from archaeological sites, located along wadis or close to lakes, and sedimentary sequences from permanent and dried basins demonstrate that water has always been an attractive environmental feature, especially during periods of drought. This paper reports on two very different examples of Holocene sites where “humans and water” coexisted during dry periods, as observed by stratigraphic, archaeological and palynological evidence. Independent research was carried out on the Jefara Plain (Libya, 32°N) and the Gobero area (Niger, 17°N), at the extreme northern and southern limits of the Sahara, respectively. The histories of the Jefara and Gobero areas, as revealed by the archaeological and palaeoenvironmental reconstructions, suggest that these areas were likely to have been visited and exploited for a long time, acting as anthropic refugia, and therefore they have been profoundly transformed. Human presence and actions have conditioned the local growing of plants and selected a more or less synanthropic flora. Today, modern conservation strategies should take into consideration that water reservoirs, which are crucial for the long-term conservation of biodiversity, have provided refugia in the past just as they presently do under global warming conditions

Outils statistiques pour l’étude de la production et de l’utilisation de la céramique au Sahara et au Soudan

Les études les plus récentes ont démontré que la classification de la céramique peut être beaucoup plus instructive si l’intégralité de la chaîne opératoire est identifiée et décrite. Cette méthode d’analyse a été appliquée aux collections provenant de l’Adrar Bous (Niger) au Sahara méridional et d’Esh Shaheinab (Soudan) dans la haute vallée du Nil. Jusqu’à présent le décor a été particulièrement important pour la définition de la poterie saharienne et soudanaise. Dans cette étude, il est replacé parmi les nombreuses étapes du processus de fabrication. L’approvisionnement en matière première, le choix et la préparation de l’argile, les techniques décoratives, l’utilisation et l’abandon des pots ont été enregistrés dans une base de données Access®. Ils ont été organisés sous forme hiérarchique imbriquée à l’aide d’un système de formulaires liés associés à des requêtes croisées. En outre, l’étude spatiale du site de l’Adrar Bous a fait l’objet d’une analyse géostatistique : la variabilité de la densité de céramique a été calculée et reportée sous forme de courbes d’iso-densité dans la cartographie du site.Most recent studies on ceramics have demonstrated that their classification can be much more informative if the entire production sequence of pottery manufacturing is identified and described. This method of analysis of the manufacturing chaîne opératoire has been applied to collections from Adrar Bous (Niger) in the southern Sahara, and Esh Shaheinab (Sudan) in the upper Nile valley. Although ceramic decorations are a considerable component in Saharan and Sudanese pottery, the present approach conceives them as one of the numerous stages of the manufacturing process. All information regarding raw material procurement, assessment and preparation of the clay, decorative techniques, use and discard of the pots were entered in a database on Access®  platform. They were organised in a nested hierarchy through a system of linked userforms with crossed field queries. Furthermore, geostatistical analysis was applied to determine the spatial structure of data at an archaeological site in the Adrar Bous. Abundance of pottery as pattern of variation was calculated and mapped as a contour map of the site

Perioperative standard oral nutrition supplements versus immunonutrition in patients undergoing colorectal resection in an Enhanced Recovery (ERAS) protocol

To compare immunonutrition versus standard high calorie nutrition in patients undergoing elective colorectal resection within an Enhanced Recovery After Surgery (ERAS) program. Despite progress in recent years in the surgical management of patients with colorectal cancer (ERAS programs), postoperative complications are frequent. Nutritional supplements enriched with immunonutrients have recently been introduced into clinical practice. However, the extent to which the combination of ERAS protocols and immunonutrition benefits patients undergoing colorectal cancer surgery is unknown. The SONVI study is a prospective, multicenter, randomized trial with 2 parallel treatment groups receiving either the study product (an immune-enhancing feed) or the control supplement (a hypercaloric hypernitrogenous supplement) for 7 days before colorectal resection and 5 days postoperatively. A total of 264 patients were randomized. At baseline, both groups were comparable in regards to age, sex, surgical risk, comorbidity, and analytical and nutritional parameters. The median length of the postoperative hospital stay was 5 days with no differences between the groups. A decrease in the total number of complications was observed in the immunonutrition group compared with the control group, primarily due to a significant decrease in infectious complications (23.8% vs. 10.7%, P=0.0007). Of the infectious complications, wound infection differed significantly between the groups (16.4% vs. 5.7%, P=0.0008). Other infectious complications were lower in the immunonutrition group but were not statistically significantly different. The implementation of ERAS protocols including immunonutrient-enriched supplements reduces the complications of patients undergoing colorectal resection

Archaeology of Holocene hunter-gatherers at the sixth Nile cataract, central Sudan

Jebel Sabaloka at the Sixth Nile Cataract has been known for its strategic importance in late prehistoric stone tool production in central Sudan. Since 2009, archaeological exploration on the west bank of the Nile has revealed a hierarchized settlement structure, with 30 sites of early to mid-Holocene dating. The key findings derive from two principal sites – Sphinx and Fox Hill – that are situated on large granite outcrops and provide evidence of robust occupation by hunter-gatherers of the Early Khartoum Complex (Khartoum Mesolithic, ca. 8,500–5,000 BC). One of the most intriguing elements at these Early Khartoum settlements is the presence of large hunter gatherer burial grounds, which will enrich the discussions of the character, duration and structuring of these Mesolithic societies at both regional and supra-regional level

Lakeside Cemeteries in the Sahara: 5000 Years of Holocene Population and Environmental Change

Background: Approximately two hundred human burials were discovered on the edge of a paleolake in Niger that providea uniquely preserved record of human occupation in the Sahara during the Holocene (,8000 B.C.E. to the present). CalledGobero, this suite of closely spaced sites chronicles the rapid pace of biosocial change in the southern Sahara in response tosevere climatic fluctuation.Methodology/Principal Findings: Two main occupational phases are identified that correspond with humid intervals in theearly and mid-Holocene, based on 78 direct AMS radiocarbon dates on human remains, fauna and artifacts, as well as 9 OSLdates on paleodune sand. The older occupants have craniofacial dimensions that demonstrate similarities with mid-Holocene occupants of the southern Sahara and Late Pleistocene to early Holocene inhabitants of the Maghreb. Theirhyperflexed burials compose the earliest cemetery in the Sahara dating to ,7500 B.C.E. These early occupants abandon thearea under arid conditions and, when humid conditions return ,4600 B.C.E., are replaced by a more gracile people withelaborated grave goods including animal bone and ivory ornaments.Conclusions/Significance: The principal significance of Gobero lies in its extraordinary human, faunal, and archaeologicalrecord, from which we conclude the following:(1) The early Holocene occupants at Gobero (7700–6200 B.C.E.) were largely sedentary hunter-fisher-gatherers withlakeside funerary sites that include the earliest recorded cemetery in the Sahara.(2) Principal components analysis of craniometric variables closely allies the early Holocene occupants at Gobero with askeletally robust, trans-Saharan assemblage of Late Pleistocene to mid-Holocene human populations from the Maghreband southern Sahara.(3) Gobero was abandoned during a period of severe aridification possibly as long as one millennium (6200–5200 B.C.E).(4) More gracile humans arrived in the mid-Holocene (5200–2500 B.C.E.) employing a diversified subsistence economybased on clams, fish, and savanna vertebrates as well as some cattle husbandry.(5) Population replacement after a harsh arid hiatus is the most likely explanation for the occupational sequence at Gobero.(6) We are just beginnin

MicroRNAs targeting oncogenes are down-regulated in pancreatic malignant transformation from benign tumors

BACKGROUND MicroRNA (miRNA) expression profiles have been described in pancreatic ductal adenocarcinoma (PDAC), but these have not been compared with pre-malignant pancreatic tumors. We wished to compare the miRNA expression signatures in pancreatic benign cystic tumors (BCT) of low and high malignant potential with PDAC, in order to identify miRNAs deregulated during PDAC development. The mechanistic consequences of miRNA dysregulation were further evaluated. METHODS Tissue samples were obtained at a tertiary pancreatic unit from individuals with BCT and PDAC. MiRNA profiling was performed using a custom microarray and results were validated using RT-qPCR prior to evaluation of miRNA targets. RESULTS Widespread miRNA down-regulation was observed in PDAC compared to low malignant potential BCT. We show that amongst those miRNAs down-regulated, miR-16, miR-126 and let-7d regulate known PDAC oncogenes (targeting BCL2, CRK and KRAS respectively). Notably, miR-126 also directly targets the KRAS transcript at a "seedless" binding site within its 3'UTR. In clinical specimens, miR-126 was strongly down-regulated in PDAC tissues, with an associated elevation in KRAS and CRK proteins. Furthermore, miR-21, a known oncogenic miRNA in pancreatic and other cancers, was not elevated in PDAC compared to serous microcystic adenoma (SMCA), but in both groups it was up-regulated compared to normal pancreas, implicating early up-regulation during malignant change. CONCLUSIONS Expression profiling revealed 21 miRNAs down-regulated in PDAC compared to SMCA, the most benign lesion that rarely progresses to invasive carcinoma. It appears that miR-21 up-regulation is an early event in the transformation from normal pancreatic tissue. MiRNA expression has the potential to distinguish PDAC from normal pancreas and BCT. Mechanistically the down-regulation of miR-16, miR-126 and let-7d promotes PDAC transformation by post-transcriptional up-regulation of crucial PDAC oncogenes. We show that miR-126 is able to directly target KRAS; re-expression has the potential as a therapeutic strategy against PDAC and other KRAS-driven cancers