Time and Frequency domain design of Functional Filters

Abstract-This paper proposes both time and frequency domain design of functional filters for linear time-invariant multivariable systems where all measurements are affected by disturbances. The order of this filter is equal to the dimension of the vector to be estimated. The time procedure design is based on the unbiasedness of the filter using a Sylvester equation; then the problem is expressed in a singular system one and is solved via Linear Matrix Inequalities (LMI) to find the optimal gain implemented in the observer design. The frequency procedure design is derived from time domain results by defining some useful Matrix Fractions Descriptions (MFDs) and mainly, establishing the useful and equivalent form of the connecting relationship that parameterizes the dynamic behavior between time and frequency domain, given by Hippe in the reduced-order case. A numerical example is given to illustrate our approach

Numerical study of the THM effects on the near-field safety of a hypothetical nuclear waste repository—BMT1 of the DECOVALEX III project. Part 1: Conceptualization and characterization of the problems and summary of results

11 pagesInternational audienceGeological disposal of the spent nuclear fuel often uses the concept of multiple barrier systems. In order to predict the performance of these barriers, mathematical models have been developed, verified and validated against analytical solutions, laboratory tests and field experiments within the international DECOVALEX III project. These models in general consider the full coupling of thermal (T), hydraulic (H) and mechanical (M) processes that would prevail in the geological media around the repository. For Bench Mark Test no. 1 (BMT1) of the DECOVALEX III project, seven multinational research teams studied the implications of coupled THM processes on the safety of a hypothetical nuclear waste repository at the near-field and are presented in three accompanying papers in this issue. This paper is the first of the three companion papers, which provides the conceptualization and characterization of the BMT1 as well as some general conclusions based on the findings of the numerical studies. It also shows the process of building confidence in the mathematical models by calibration with a reference T–H–M experiment with realistic rock mass conditions and bentonite properties and measured outputs of thermal, hydraulic and mechanical variables

Numerical study of the THM effects on the near-field safety of a hypothetical nuclear waste repository—BMT1 of the DECOVALEX III project. Part 2: Effects of THM coupling in continuous and homogeneous rocks

14 pagesInternational audienceAn evaluation of the importance of the thermo-hydro-mechanical couplings (THM) on the performance assessment of a deep underground radioactive waste repository has been made as a part of the international DECOVALEX III project. It is a numerical study that simulates a generic repository configuration in the near field in a continuous and homogeneous hard rock. A periodic repository configuration comprises a single vertical borehole, containing a canister surrounded by an over-pack and a bentonite layer, and the backfilled upper portion of the gallery. The thermo-hydro-mechanical evolution of the whole configuration is simulated over a period of 100 years. The importance of the rock mass's intrinsic permeability has been investigated through scoping calculations with three values: 10−17, 10−18 and 10−19 m2. Comparison of the results predicted by fully coupled THM analysis as well as partially coupled TH, TM and HM analyses, in terms of several predefined indicators of importance for performance assessment, enables us to identify the effects of the different combinations of couplings, which play a crucial role with respect to safety issues. The results demonstrate that temperature is hardly affected by the couplings. In contrast, the influence of the couplings on the mechanical stresses is considerable

Diversité Inter Décennale De La Végétation De La Vallée De Goulbi N’Kaba

The present study is conducted in the Sylvo-Pastoral Zone (ZSP) of the Goulbi N'Kaba Valley and the agricultural zone (fields on adjacent terraces), in the southern center of Niger. The objective of the study is to evaluate the inter-decennial plant biodiversity (2004-2014). Thus, the phytosociological surveys (Daget and Poissonet, 1971) were carried out in plots of 2500 m², along the 6.5 km transects following stratified sampling. An ascending hierarchical classification, followed by an ordination by Nonmetric Multi-dimensional Scaling (NMS) allowed to identify the plant groups. The diversity of each group was evaluated. The results show that the families of Poaceae and Fabaceae are the most abundant in 2004 (15.58% and 11.69%) and in 2014 (18.75% and 7.29%). However, compared to the genera, Indigofera (10.53%), Cassia (6.58%), Acacia (5.26%), Aristida (5.26%) are the most abundant in 2004, while Aristida (4 , 17%), Cassia (4.17%), Spermacoce (3.13%), in 2014. Three groups (mixed, fields, ZSP) have been identified. The 2004 and 2014 index, of Margalef (18,38 and 11,28), Menhinick (2,55 and 1,52), Shannon-Weaver (4,77 and 4,14), the fairness of Pielou (0, 66 and 0.63), the Simpson index (0.89 and 0.91) and Hill (0.95 and 0.93) are high in all the groups, mixed, fields and ZSP (respectively for G1, G2 and G3). But the beta diversity (Whittaker (24), Jaccard (0.52), Sorensen (0.69) index) for each of these groupings remains low. There was no significant change in inter-decennial diversity at the Guidan Tawayé and Korin Habdjia sites from 2004 to 2014

Genetic Variability and Its Implications on Early Generation Sorghum Lines Selection for Yield, Yield Contributing Traits, and Resistance to Sorghum Midge

Sorghum is the second most important cereal crop in Niger. The crop is grown in a wide range of ecological environments in the country. However, sorghum grain yield in Niger is limited by both abiotic and biotic constraints. Recombinant inbred lines derived from the cross of a local variety with a midge resistant variety and two local checks were evaluated during the 2015 rainy season across two planting dates in two environments in Niger. The objective was to investigate genetic variability for yield, yield related traits, and resistance to sorghum midge. High phenotypic coefficient of variation (PCV) versus genotypic coefficient of variation (GCV) was observed in both sites and planting dates. Across planting dates at both Konni and Maradi, grain yield, plant height, panicle weight, and midge damage had high heritability coupled with high estimates of genetic advance. At Konni, high genetic advance coupled with high heritability was detected for grain yield, plant height, panicle weight, and resistance to midge. There were similar results at Maradi for grain yield, plant height, and panicle weight. Therefore, selection might be successful for the above characters in their respective environments

P2 receptors in atherosclerosis and postangioplasty restenosis

Atherosclerosis is an immunoinflammatory process that involves complex interactions between the vessel wall and blood components and is thought to be initiated by endothelial dysfunction [Ross (Nature 362:801–09, 1993); Fuster et al. (N Engl J Med 326:242–50, 1992); Davies and Woolf (Br Heart J 69:S3–S11, 1993)]. Extracellular nucleotides that are released from a variety of arterial and blood cells [Di Virgilio and Solini (Br J Pharmacol 135:831–42, 2002)] can bind to P2 receptors and modulate proliferation and migration of smooth muscle cells (SMC), which are known to be involved in intimal hyperplasia that accompanies atherosclerosis and postangioplasty restenosis [Lafont et al. (Circ Res 76:996–002, 1995)]. In addition, P2 receptors mediate many other functions including platelet aggregation, leukocyte adherence, and arterial vasomotricity. A direct pathological role of P2 receptors is reinforced by recent evidence showing that upregulation and activation of P2Y2 receptors in rabbit arteries mediates intimal hyperplasia [Seye et al. (Circulation 106:2720–726, 2002)]. In addition, upregulation of functional P2Y receptors also has been demonstrated in the basilar artery of the rat double-hemorrhage model [Carpenter et al. (Stroke 32:516–22, 2001)] and in coronary artery of diabetic dyslipidemic pigs [Hill et al. (J Vasc Res 38:432–43, 2001)]. It has been proposed that upregulation of P2Y receptors may be a potential diagnostic indicator for the early stages of atherosclerosis [Elmaleh et al. (Proc Natl Acad Sci U S A 95:691–95, 1998)]. Therefore, particular effort must be made to understand the consequences of nucleotide release from cells in the cardiovascular system and the subsequent effects of P2 nucleotide receptor activation in blood vessels, which may reveal novel therapeutic strategies for atherosclerosis and restenosis after angioplasty

The weakest link: competence and prestige as constraints to referral by isolated nurses in rural Niger

BACKGROUND: For a health district to function referral from health centres to district hospitals is critical. In many developing countries referral systems perform well below expectations. Niger is not an exception in this matter. Beyond obvious problems of cost and access this study shows to what extent the behaviour of the health worker in its interaction with the patient can be a barrier of its own. METHODS: Information was triangulated from three sources in two rural districts in Niger: first, 46 semi-structured interviews with health centre nurses; second, 42 focus group discussions with an average of 12 participants – patients, relatives of patients and others; third, 231 semi-structured interviews with referred patients. RESULTS: Passive patients without 'voice' reinforce authoritarian attitudes of health centre staff. The latter appear reluctant to refer because they see little added value in referral and fear loss of power and prestige. As a result staff communicates poorly and show little eagerness to convince reluctant patients and families to accept referral proposals. CONCLUSIONS: Diminishing referral costs and distance barriers is not enough to correct failing referral systems. There is also a need for investment in district hospitals to make referrals visibly worthwhile and for professional upgrading of the human resources at the first contact level, so as to allow for more effective referral patterns

Disentangling the role of Africa in the global spread of H5 highly pathogenic avian influenza

The role of Africa in the dynamics of the global spread of a zoonotic and economicallyimportant virus, such as the highly pathogenic avian influenza (HPAI) H5Nx of the Gs/GD lineage, remains unexplored. Here we characterise the spatiotemporal patterns of virus diffusion during three HPAI H5Nx intercontinental epidemic waves and demonstrate that Africa mainly acted as an ecological sink of the HPAI H5Nx viruses. A joint analysis of host dynamics and continuous spatial diffusion indicates that poultry trade as well as wild bird migrations have contributed to the virus spreading into Africa, with West Africa acting as a crucial hotspot for virus introduction and dissemination into the continent. We demonstrate varying paths of avian influenza incursions into Africa as well as virus spread within Africa over time, which reveal that virus expansion is a complex phenomenon, shaped by an intricate interplay between avian host ecology, virus characteristics and environmental variables.USAID under the OSRO/GLO/501/USA and OSRO/GLO/507/USA projects and by European Union’s Horizon 2020 research and innovation programme under grant agreement No 727922 (DELTAFLU). The European Research Council under the European Unionʼs Horizon 2020 research and innovation programme (grant agreement no. 725422-ReservoirDOCS). P.L. acknowledges support by the Research Foundation – Flanders FWO, G066215N, G0D5117N and G0B9317N). B.V. is a postdoctoral research fellow supported by the FWO.http://www.nature.com/naturecommunicationsam2020Microbiology and Plant Patholog