Time Segmentation Approach Allowing QoS and Energy Saving for Wireless Sensor Networks

Wireless sensor networks are conceived to monitor a certain application or physical phenomena and are supposed to function for several years without any human intervention for maintenance. Thus, the main issue in sensor networks is often to extend the lifetime of the network by reducing energy consumption. On the other hand, some applications have high priority traffic that needs to be transferred within a bounded end-to-end delay while maintaining an energy efficient behavior. We propose MaCARI, a time segmentation protocol that saves energy, improves the overall performance of the network and enables quality of service in terms of guaranteed access to the medium and end-to-end delays. This time segmentation is achieved by synchronizing the activity of nodes using a tree-based beacon propagation and allocating activity periods for each cluster of nodes. The tree-based topology is inspired from the cluster-tree proposed by the ZigBee standard. The efficiency of our protocol is proven analytically, by simulation and through real testbed measurements

Propofol Directly Increases Tau Phosphorylation

In Alzheimer's disease (AD) and other tauopathies, the microtubule-associated protein tau can undergo aberrant hyperphosphorylation potentially leading to the development of neurofibrillary pathology. Anesthetics have been previously shown to induce tau hyperphosphorylation through a mechanism involving hypothermia-induced inhibition of protein phosphatase 2A (PP2A) activity. However, the effects of propofol, a common clinically used intravenous anesthetic, on tau phosphorylation under normothermic conditions are unknown. We investigated the effects of a general anesthetic dose of propofol on levels of phosphorylated tau in the mouse hippocampus and cortex under normothermic conditions. Thirty min following the administration of propofol 250 mg/kg i.p., significant increases in tau phosphorylation were observed at the AT8, CP13, and PHF-1 phosphoepitopes in the hippocampus, as well as at AT8, PHF-1, MC6, pS262, and pS422 epitopes in the cortex. However, we did not detect somatodendritic relocalization of tau. In both brain regions, tau hyperphosphorylation persisted at the AT8 epitope 2 h following propofol, although the sedative effects of the drug were no longer evident at this time point. By 6 h following propofol, levels of phosphorylated tau at AT8 returned to control levels. An initial decrease in the activity and expression of PP2A were observed, suggesting that PP2A inhibition is at least partly responsible for the hyperphosphorylation of tau at multiple sites following 30 min of propofol exposure. We also examined tau phosphorylation in SH-SY5Y cells transfected to overexpress human tau. A 1 h exposure to a clinically relevant concentration of propofol in vitro was also associated with tau hyperphosphorylation. These findings suggest that propofol increases tau phosphorylation both in vivo and in vitro under normothermic conditions, and further studies are warranted to determine the impact of this anesthetic on the acceleration of neurofibrillary pathology

Dimethyl Sulfoxide Induces Both Direct and Indirect Tau Hyperphosphorylation

Dimethyl sulfoxide (DMSO) is widely used as a solvent or vehicle for biological studies, and for treatment of specific disorders, including traumatic brain injury and several forms of amyloidosis. As Alzheimer’s disease (AD) brains are characterized by deposits of β-amyloid peptides, it has been suggested that DMSO could be used as a treatment for this devastating disease. AD brains are also characterized by aggregates of hyperphosphorylated tau protein, but the effect of DMSO on tau phosphorylation is unknown. We thus investigated the impact of DMSO on tau phosphorylation in vitro and in vivo. One hour following intraperitoneal administration of 1 or 2 ml/kg DMSO in mice, no change was observed in tau phosphorylation. However, at 4 ml/kg, tau was hyperphosphorylated at AT8 (Ser202/Thr205), PHF-1 (Ser396/Ser404) and AT180 (Thr231) epitopes. At this dose, we also noticed that the animals were hypothermic. When the mice were maintained normothermic, the effect of 4 ml/kg DMSO on tau hyperphosphorylation was prevented. On the other hand, in SH-SY5Y cells, 0.1% DMSO induced tau hyperphosphorylation at AT8 and AT180 phosphoepitopes in normothermic conditions. Globally, these findings demonstrate that DMSO can induce tau hyperphosphorylation indirectly via hypothermia in vivo, and directly in vitro. These data should caution researchers working with DMSO as it can induce artifactual results both in vivo and in vitro

Linking disease epidemiology and livestock productivity: the case of bovine respiratory disease in France

Concerns are growing over the impact of livestock farming on environment and public health. The livestock industry is faced with the double constraint of limiting its use of natural resources and antimicrobials while ensuring its economic sustainability. In this context, reliable methods are needed to evaluate the effect of the prevention of endemic animal diseases on the productivity of livestock production systems. In this study, an epidemiological and productivity model was used to link changes in Bovine Respiratory Disease (BRD) incidence with the productivity of the beef and dairy cattle sectors in France. Cattle production parameters significantly affected by BRD were selected through literature review. Previous field study results and national cattle performance estimates were used to infer growth performances, mortality rates and carcass quality in the cattle affected and not affected by BRD. A steady-state deterministic herd production model was used to predict the productivity of the dairy and beef sector and their defined compartments (breeding-fattening, feedlot young bulls, and feedlot veal) in case of BRD incidence reduction by 20%, 50% or 100%. Results suggested that BRD should be controlled at a priority in beef breeding farms as eradication of BRD in beef calves would increase the whole beef sector’s productivity by 4.7–5.5% while eradication in other production stages would result in lower productivity gain in their respective sectors. However, the analysis performed at compartment level showed that, in both the beef and dairy sector, young bull and veal feedlot enterprises derive more economic benefits from BRD eradication for their own compartment (increase in productivity of 8.7–12.8% for beef young bulls) than the breeding farms (increase in productivity of 5.1–6% for beef calves), which may limit the investments in BRD control

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Optimisation et compréhension de procédés d'ignifugation de polymères techniques

Ce travail porte sur les procédés d'ignifugation du polyamide-6,6 (PA), un polymère technique utilisé pour l'application électrique. Le pyrophosphate et le polyphosphate de mélamine sont deux additifs intumescents dont l'incorporation, dans le PA, vierge ou renforcé par des fibres de verre, permet l'obtention de propriétés retard au feu (FR) et la satisfaction d'un cahier des charges industriel. De plus, la présence du renfort minéral induit des modifications des performances feu. L'étude est donc orientée sur la compréhension des influences des additifs FR et des fibres de verre sur les propriétés feu des formulations. Les stabilités thermiques sous air des matériaux sont évaluées, pour comprendre le mode de protection feu. L'existence d'interactions entre la matrice polymère et les additifs sont mises en évidence. Elles entraînent, entre autres, la formation d'un résidu stable aux températures élevées. Par ailleurs, des interactions entre le renfort minéral et les systèmes FR sont également observées. La modélisation cinétique des processus de dégradation des différents systèmes, en utilisant la méthode des paramètres cinétiques invariants, permet la compréhension des influences des adjuvants et des fibres sur les mécanismes de dégradation des matériaux. L'étude des effluents de dégradation des matériaux, sous différentes conditions, permet de caractériser les effets des additifs et des fibres de verre sur la composition de la phase gaz. Une contribution de cette dernière à la protection feu du matériau peut être supposée. Enfin, une approche chimique de la dégradation des matériaux permet de proposer un mécanisme de protection feu au sein de la phase condensée, via la formation d'une couche intumescente contenant une structure phosphocarbonée stable. Finalement, il est montré que la charge de renfort modifie la chimie de dégradation des systèmes FR.LILLE1-BU (590092102) / SudocSudocFranceF

Résolution de systèmes de contraintes réelles non linéaires

NICE-BU Sciences (060882101) / SudocSudocFranceF

Phylogeny of West African Caryedon (Coleoptera : Bruchidae) : congruence between molecular and morphological data

Seed beetles belonging to the Old World genus #Caryedon feed in the seeds of various #Caesalpinioidae, #Mimosoidae$, and Combretaceae$. In an attempt to resolve broad phylogenetic relationships within the genus, we obtained 332 base pair sequences of mitochondrial 12S ribosomal DNA and morphological data for the 16 West African #Caryedon species. Morphological characters were analyzed under maximum parsimony and sequences were compared under maximum parsimony, maximum likelihood, and neighbor joining. Using a partition homogeneity test, we determined that morphological and molecular data sets were combinable. Combined data were analyzed under maximum parsimony. Morphological and molecular trees were congruent at the species group level and total evidence analyses yielded the same topologies as molecular data with each of the three outgroups used. Four main terminal clades are recognized, each corresponding with a group of species generally feeding on the same host plant family, subfamily, genus, or species. The monophyly of legume feeding #Caryedon is supported by both data sets, and #Combretaceae$ feeders split in two monophyletic assemblages. (Résumé d'auteur

Phylogeny of West African Caryedon (Coleoptera : Bruchidae) : congruence between molecular and morphological data

Seed beetles belonging to the Old World genus #Caryedon feed in the seeds of various #Caesalpinioidae, #Mimosoidae$, and Combretaceae$. In an attempt to resolve broad phylogenetic relationships within the genus, we obtained 332 base pair sequences of mitochondrial 12S ribosomal DNA and morphological data for the 16 West African #Caryedon species. Morphological characters were analyzed under maximum parsimony and sequences were compared under maximum parsimony, maximum likelihood, and neighbor joining. Using a partition homogeneity test, we determined that morphological and molecular data sets were combinable. Combined data were analyzed under maximum parsimony. Morphological and molecular trees were congruent at the species group level and total evidence analyses yielded the same topologies as molecular data with each of the three outgroups used. Four main terminal clades are recognized, each corresponding with a group of species generally feeding on the same host plant family, subfamily, genus, or species. The monophyly of legume feeding #Caryedon is supported by both data sets, and #Combretaceae$ feeders split in two monophyletic assemblages. (Résumé d'auteur

Analysis of the delay of confirmed downlink frames in Class B of LoRaWAN

International audienceWireless sensor networks have long been characterized by short range communications. Lately, long range wireless sensor networks such as LoRaWAN (long range wide area network) have emerged, increasing the communication range at the cost of reduced bit rate. This paper focuses on the MAC layer of LoRaWAN and studies communications from a gateway to an end-device. We propose a Markov chain model to estimate the delivery delay of an acknowledged communication (with retransmissions) and study the impact of the number of channels, the data-rate and the number of nodes