A method is proposed for synthesizing output feedback controllers for nonlinear Lur' e systems . The problem of designing an output dynamic controller for uncertain-free systems and systems subject to multiplicati...A method is proposed for synthesizing output feedback controllers for nonlinear Lur' e systems . The problem of designing an output dynamic controller for uncertain-free systems and systems subject to multiplicative norm-bounded perturbations in the linear part were proposed respectively. The procedure is based on the use of the absolute stability, through the circle criterion, and a linear matrix inequalities (LAI) formulation. The controller existence conditions are given in terms of existence of suitable solutions to a set of parameter-dependent LMIs.展开更多
The intrinsic physical properties of the noble metal nanoparticles,which are highly sensitive to the nature of their local molecular environment,make such systems ideal for the detection of molecular recognition event...The intrinsic physical properties of the noble metal nanoparticles,which are highly sensitive to the nature of their local molecular environment,make such systems ideal for the detection of molecular recognition events.The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles.In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization.A brief discussion of the three common methods of functionalization:Electrostatic adsorption;Chemisorption;Affinity-based coordination is given.In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition.In the main section the various types of capping agents for molecular recognition;nucleic acid coatings,protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications.Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition.For the proteins the recognition properties of antibodies form the core of the section.With respect to the supramolecular systems the cyclodextrins,calix[n]arenes,dendrimers,crown ethers and the cucurbitales are treated in depth.Finally a short section deals with the possible toxicity of the nanoparticles,a concern in public health.展开更多
In Senegal, tomato (<i><span style="font-family:Verdana;">Solanum lycopersicum</span></i><span style="font-family:Verdana;"> L.) cultivation is affected by salinity in...In Senegal, tomato (<i><span style="font-family:Verdana;">Solanum lycopersicum</span></i><span style="font-family:Verdana;"> L.) cultivation is affected by salinity in many agro-ecological zones. The selection of salt tolerant varieties would be an alternative solution to enhance the production. Thus, germination and growth are studied under axenic conditions for five varieties of tomato subjected to increasing concentrations of NaCl [0, 35, 70 and 105 mM], and supplemented in an MS/2 medium for 30 days. The results reveal that salt negatively affects the evaluated parameters. The </span><i><span style="font-family:Verdana;">Rodeo</span></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Lady Nema </span></i><span style="font-family:Verdana;">varieties have the lowest final germination rates (50%) unlike the </span><i><span style="font-family:Verdana;">Mongal</span></i><span style="font-family:Verdana;"> variety (55%). These last two varieties have a decrease of 71.78% and 81.28% in the height of the stem, respectively, in the presence of NaCl at [105 mM] while that of the </span><i><span style="font-family:Verdana;">Rodeo</span></i><span style="font-family:Verdana;"> variety is 70%. The </span><i><span style="font-family:Verdana;">Xewel</span></i><span style="font-family:Verdana;"> variety has the greatest average number of leaves in the presence of [NaCl 35 mM] (4.95 leaves) and [NaCl 70 mM] (4.77 leaves). The </span><i><span style="font-family:Verdana;">Lady Nema</span></i><span style="font-family:Verdana;"> variety records the longest taproot length (2.99 cm) unlike the </span><i><span style="font-family:Verdana;">Rodeo</span></i><span style="font-family:Verdana;"> variety (2.25 cm) at [NaCl 105 mM]. The </span><i><span style="font-family:Verdana;">Ganila</span></i><span style="font-family:Verdana;"> variety reveals the highest number of secondary roots at the concentrations of [0, 35 and 105 mM] of NaCl with, respectively, 44.12, 29.25, and 4.25 roots. The </span><i><span style="font-family:Verdana;">Lady Nema</span></i><span style="font-family:Verdana;"> variety records the highest fresh weight of aerial (0.055 g) and root parts (0.014 g) and the lowest root dry weights (0.0023 g). These results allow to conclude that the </span><i><span style="font-family:Verdana;">Lady Nema </span></i><span style="font-family:Verdana;">and</span><i><span style="font-family:Verdana;"> Mongal</span></i><span style="font-family:Verdana;"> varieties seem more tolerant, </span><i><span style="font-family:Verdana;">Ganila </span></i><span style="font-family:Verdana;">and</span><i><span style="font-family:Verdana;"> Xewel</span></i><span style="font-family:Verdana;"> are moderately tolerant and </span><i><span style="font-family:Verdana;">Rodeo</span></i><span style="font-family:Verdana;"> is more sensitive to the presence of salt.</span>展开更多
Fast recovery and minimum utilization of resources are the two main criteria for determining the protection scheme quality. We address the problem of providing a hybrid protection approach on elastic optical networks ...Fast recovery and minimum utilization of resources are the two main criteria for determining the protection scheme quality. We address the problem of providing a hybrid protection approach on elastic optical networks under contiguity and continuity of available spectrum constraints. Two main hypotheses are used in this paper for backup paths computation. In the first case, it is assumed that backup paths resources are dedicated. In the second case, the assumption is that backup paths resources are available shared resources. The objective of the study is to minimize spectrum utilization to reduce blocking probability on a network. For this purpose, an efficient survivable Hybrid Protection Lightpath （HybPL） algorithm is proposed for providing shared or dedicated backup path protection based on the efficient energy calculation and resource availability. Traditional First-Fit and Best-Fit schemes are employed to search and assign the available spectrum resources. The simulation results show that HybPL presents better performance in terms of blocking probability, compared with the Minimum Resources Utilization Dedicated Protection （MRU-DP） algorithm which offers better performance than the Dedicated Protection （DP） algorithm.展开更多
Bambara groundnut [Vigna subterranean (L.) Verdc] is a food legume with high potential for food security in Sub-Saharan Africa. However, in addition to being a neglected crop, its production is limited by several cons...Bambara groundnut [Vigna subterranean (L.) Verdc] is a food legume with high potential for food security in Sub-Saharan Africa. However, in addition to being a neglected crop, its production is limited by several constraints among which viral diseases are most cited. In order to contribute to the improvement of Bambara groundnut in Burkina Faso, local accessions of the crop were screened for resistance to Cowpea mottle virus (CPMoV), one of the most damaging viruses in grain legumes. Seven local accessions (C1 to C7) from two agro-ecological zones were evaluated by mechanical inoculation in field conditions in 2016 and 2017. The infected plants exhibited various symptoms of chlorosis, leaf deformation, growth retardation and plant stunting. CPMoV caused a significant reduction in the number of flowers and pods. As a result, grain yield was reduced by 49.5% to 83.9% depending on the accessions. The impact of the virus in yield loss was lowest in accessions C6 and C7 which indicated their possible used in the management of Cowpea mottle virus disease in bambara groundnut.展开更多
<i><span style="font-family:"">Annona</span></i><span style="font-family:""> <i>muricata</i> L. and <i>Annona</i> <i>squamosa&l...<i><span style="font-family:"">Annona</span></i><span style="font-family:""> <i>muricata</i> L. and <i>Annona</i> <i>squamosa</i> L. are tropical species whose</span><span style="font-family:""> fleshy fruit is edible. They offer real possibilities for socio-economic use, particularly in the fields of medicine, nutrition, ecosystem conservation and the poverty alleviation. This study was set up to evaluate different methods of micropropagation from juvenile material for the regeneration of these species. Thus, MS medium supplemented with [BAP 2 mg·L<sup>-1</sup>] <i>i.e.</i> M2 produced 2.87 newly <span>formed shoots from the cotyledonary nodes of <i>A.</i> <i>muricata</i>. For the terminal apices of <i>A.</i> <i>squamosa</i>, it was MMS medium supplemented with [BAP 2</span> mg·L<sup>-1</sup>] <i>i.e.</i> MM2 that was most conducive to new shoot formation (3.12). The addition of 0.1 and 0.2 mg·L<sup>-1</sup> of NAA in the M2 medium, made it possi<span>ble to have the best elongations and average number of nodes for the new shoots from cotyledonary nodes of <i>A.</i> <i>muricata</i> (9.11 cm for 5.62 nodes). With <i>A.</i> <i>squamosa</i>, MM7 medium [MMS + BAP 1 mg·L<sup>-1</sup></span></span><span style="font-family:""> </span><span style="font-family:"">+ KIN 1 mg·L<sup>-1</sup>]</span><span style="font-family:""> resulted in an average length of 9.05 cm with 5.62 nodes on average for the apical shoots. A 3-day rhizogenic induction period in the dark with [IBA 50 mg·L<sup>-1</sup>] and 2 g·L<sup>-1</sup> of activated charcoal gave a rooting rate of 66.67% for shoots originating from the cotyledonary nodes of <i>A.</i> <i>squamosa</i>;while with vitroplants from cotyledonary nodes of <i>A.</i> <i>muricata</i>, a better rooting rate (83.33%) was obtained following a 5-day rhizogenic induction. After 30 days of acclimatization, the survival rate reached 83.33% for plants from the tips of <i>A.</i> <i>muricata</i>, whereas for <i>A.</i> <i>squamosa,</i> it was plants grown from cotyledonary nodes that had the same survival rate.展开更多
Water is the main limiting factor in the cultivation of tomato (<i>Solanum lyco<span>persicum</span></i><span> L.) in Senegal. Thus, the selection of varieties tolerant to water st</sp...Water is the main limiting factor in the cultivation of tomato (<i>Solanum lyco<span>persicum</span></i><span> L.) in Senegal. Thus, the selection of varieties tolerant to water st</span>ress would be an alternative solution for their production. <i>In vitro </i>germination, growth, total chlorophyll and proline levels were studied in five varieties of tomato subjected to increasing osmotic pressures (0, 5, 10 and 15 kPa) thanks to the PEG-8000 incorporated in an MS/2 medium for 30 days. A strong sen<span>sitivity to water stress for <i>in vitro</i> seed germination in the <i>Rodeo</i> variety (4</span>1%) is recorded at 5 kPa and maintained at 15 kPa (20.83%) while it was only noticed at 15 kPa in the other tomato varieties. The <i>Xewel</i> and <i>Lady Nema</i> varieties obtained the smallest reductions in the number of leaves of vitroplants, with 30.79% and 27.97% at 15 kPa, respectively, and the <i>Rodeo</i> variety recorded a reduction of 35.97%. From 5 kPa, the varieties record reductions in <span>the number of secondary roots of more than 15%. The effect of osmotic pr</span>essures on decreasing the taproot height and length is not significant. The <i>Xewel </i>variety had the highest average fresh (0.483 g) and dry (0.082 g) weights of the aerial part at 15 kPa and the <i>Rodeo</i> variety </span><span style="font-family:"">had </span><span style="font-family:"">the lowest ones (0.308 g and 0.0501 g). The <i>Lady Nema</i> variety had the highest average fresh (0.171 g) and dry (0.039 g) root weights and the <i>Rodeo</i> variety</span><span style="font-family:""> had</span><span style="font-family:""> the lowest ones (0.086 and 0.020 g). The vitroplants of <i>Rodeo </i>variety recorded the highest decreases in total chlorophyll contents at all osmotic pressures and the lowest increase in proline content (53.37%) at 15 kPa. <i>A contrario</i>, the <i>Xewel</i> variety recorded the greatest increase in proline content (116.26%). Ultimately, the vitroplants of <i>Lady Nem</i>a and <i>Xewe</i>l varieties were more tolerant to water stress, the <i>Ganila </i>and<i> Mongal </i>varieties were moderately tolerant and the <i>Rodeo</i> variety was the most sensitive.展开更多
Imperata yellow mottle caused by Imperata yellow mottle virus (IYMV) of the genus Sobemovirus was first characterized on Imperata cylindrical and Zea mays in Burkina Faso. The disease has been reported in several loca...Imperata yellow mottle caused by Imperata yellow mottle virus (IYMV) of the genus Sobemovirus was first characterized on Imperata cylindrical and Zea mays in Burkina Faso. The disease has been reported in several localities of the country but its ecology and epidemiology are poorly known. In particular, only I. cylindrical and maize have been reported within IYMV host range. The aim of this study was to investigate the experimental host range of the virus. Mechanical inoculation of a mixture of four IYMV isolates to 18 plant species, including four crops (maize, rice, sorghum and pearl millet) and 14 wild grasses showed clear mottle symptoms in maize, sorghum and pearl millet and two wild grass species (Setaria verticillata and Rottboellia exaltata). Symptom development was confirmed by Enzyme-linked immunosorbent assay and reverse transcription–polymerase chain reaction (RT-PCR). Infection of crop species by IYMV depended on cultivars tested. Therefore, proportions of positive cultivars were 16/36 in maize, 4/10 in sorghum and 4/9 in pearl millet, respectively. Studies on virus-host interactions using individual virus isolates showed two pathogenic patterns. Three out of the four isolates tested infected all plant species and cultivars. In contrast, the fourth IYMV isolate could infect only one maize cultivar. These results expand the previously known host range of IYMV from two to five species, indicating a narrow host range. Among the new characterized host species, sorghum and pearl millet are important cereal crops. Therefore, Imperata yellow motte disease is a potential threat for the cereal crop production and its ecology and epidemiology should be thoroughly investigated.展开更多
Potyviruses are major constraints to grain legume production by causing significant yield losses. Potyviruses infecting Bambara groundnut (Vigna subterranea) were investigated in Burkina Faso. Leaf samples collected f...Potyviruses are major constraints to grain legume production by causing significant yield losses. Potyviruses infecting Bambara groundnut (Vigna subterranea) were investigated in Burkina Faso. Leaf samples collected from three agroclimatic zones were subjected to RT-PCR and sequence analyses. Of a total of 135 samples, 36 (26.67%) were detected positive in RT-PCR tests using potyvirus universal primers. Analysis of full coat protein (cp) sequences from 24 isolates revealed the occurrence of three groups of Bambara groundnut-infecting potyviruses. Virus isolates in group 1 shared 94.5% - 100% nucleotide (nt) identity with CABMV whereas those in group 2 and group 3 were distantly related Bean common necrosis virus (BCMNV) and Passiflora virus Ugandan which were their respective closest potyviruses. Group 2 shared 77.1% nt and 78.8% - 79.9% aa identity with BCMNV and group 3 shared 77.3% - 78.3% nt and 80.7% - 81.5% aa identity with Passiflora virus Ugandan. All three groups were confirmed by phylogenetic analyses. Taking into account potyvirus demarcation criteria, group 1 isolates belonged to CABMV species. Group 2 and group 3 were assigned to a potentially new potyviruses species and designated Bambara groundnut potyvirus 1 (BGPV1) and Bambara groundnut potyvirus 2 (BGPV2).展开更多
Imperata yellow mottle virus (IYMV, Sobemovirus) was first described in 2008 in the south-western region of Burkina Faso (West Africa). The genetic diversity of IYMV was not documented up to day. In this study, the va...Imperata yellow mottle virus (IYMV, Sobemovirus) was first described in 2008 in the south-western region of Burkina Faso (West Africa). The genetic diversity of IYMV was not documented up to day. In this study, the variability of CP of IYMV was evaluated through the molecular characterization of 38 isolates collected in the western part of Burkina Faso. Comparison of sequences of these new isolates and one IYMV sequence available in GenBank revealed that the average nucleotide diversity was low. The ratio of non-synonymous over synonymous nucleotide substitutions per site was low, indicating a CP diversification under strong purifying selection. Despite of the low nucleotide diversity, phylogenetic analyses revealed segregation of IYMV isolates into six major clades. There was no correlation of phylogenetic grouping of isolates based on geographical location. This is the first study of the genetic diversity of IYMV.展开更多
Satellite precipitation products are widely used in different domain, in area where there is a lack in observation. These have different spatio-temporal resolutions consequently resulting in different precipitation am...Satellite precipitation products are widely used in different domain, in area where there is a lack in observation. These have different spatio-temporal resolutions consequently resulting in different precipitation amounts depending on the product. The present study validates three satellite products, namely the Climate Hazard group Infrared Precipitation with Stations (CHIRPS), the Climate Research Unit (CRU) and the Global Precipitation Climatology Project (GPCP) over Bandama and Mono river basins for 1981-2005 and 1981-2016 respectively by comparing them to the observation precipitation of the basin. The available studies are focused on the regional scale but not on a watershed scale for hydrological studies. The analysis reveals that all the products are strongly correlated to each other as well as to the observed data at basin level. The Lamb coefficient test shows that most all the chosen basin namely Bandama and Mono presents the same climatic indices. All the products present the same variability and trend as the observation at basins scale. By comparing those products to observation, CHIRPS product following by GPCP give the lowest mean absolute error (MAE) at annual and seasonal time scales while CHIRPS is followed by CRU at monthly scale. Overall, all products overestimate the precipitation at Bandama basin while they underestimate it over Mono river basin. The comparison over 1981-2017 period of the total annual precipitation increasing southern ward (from Sahel to the coastal zone) for all the three studied products which varies from 300 mm to 2400 mm/year. All the three products are not significantly different from one another and they all highlight the same areas of hotspot rainfall in the region. The same conclusion is made at monthly and seasonal scales. Therefore, any of these products especially CHIRPS can be used for study in this region due to its lowest bias and MAE.展开更多
Annona senegalensis is a savannah species present in the wild in tropical and sub-tropical African regions. It is used by the local populations for its many economic, pharmacological, nutritional and ecological intere...Annona senegalensis is a savannah species present in the wild in tropical and sub-tropical African regions. It is used by the local populations for its many economic, pharmacological, nutritional and ecological interests. However, the strong pressure exerted on this species as well as the increasing degradation of the ecosystems, in which it evolves, seriously compromise its sustainability and development. Conventional methods of vegetative propagation are not sufficient to ensure its durable regeneration and the renewal of endemic populations in Senegal. In this context, it was undertaken in vitro propagation, from 30 days old juvenile seedlings. Thus, axillary, cotyledonary and apical nodes were in vitro cultured in Murashige and Skoog (1962) medium (MS), with different concentrations of cytokinins and/or auxins. BAP used alone at 2 mg•L<sup>−1</sup> proved to be more beneficial for micropropagation of different types of explants compared to Kinetin used alone or in combination with BAP, especially for axillary and cotyledonary nodes. The BAP-NAA combination allowed to have a better elongation of newly formed shoots. For shoots of apical and cotyledonary nodes origin, a rhizogenic induction of 5 days, with IBA at 25 mg•L<sup>−1</sup>, resulted in a better rooting rate with, respectively, 75% (for 2.22 roots) and 66.67% (for 4.17 roots). For newly formed shoots of axillary origin, a 24-hour rooting induction with IBA at 50 mg•L<sup>−1</sup> gave a rooting rate of 58.33% (for 2.4 roots). After 30 days of acclimatization, the survival rate was 75% for the young plants from the apices and 83.33% for those originating from the cotyledonary and axillary nodes. This protocol can therefore be adopted for the in vitro clonal propagation of A. senegalensis juvenile material.展开更多
Drought stress strongly affects soil biota and impairs crop production, which under climate change will be exacerbated in semi-arid cropping regions such as the Sahel. Hence soil management systems are needed that can...Drought stress strongly affects soil biota and impairs crop production, which under climate change will be exacerbated in semi-arid cropping regions such as the Sahel. Hence soil management systems are needed that can buffer against drought. In West Africa, field studies have found intercropping of millet with the native shrub Piliostigma reticulatum improves soil-plant-water relations, microbial activity and diversity, and suppress parasitic nematodes, which can significantly increase crop yield. However, little information is available on its beneficial or negative effects on soils or crops during water stress. Therefore, the objective was to investigate the impact of P. reticulatum in moderating water stress effects on soil properties and pearl millet (Pennisetum glaucum [L.] R. Br.) productivity. In the greenhouse, soil chemical and microbial properties and millet growth were investigated with a factorial experiment of varying levels of soil moisture (favorable, moderately stressed, or severely stressed water conditions) that was imposed for 55 days on soils containing sole P. reticulatum or millet, or millet + P. reticulatum. The results showed that the presence of P. reticulatum did not buffer soils against water stress in relation to soil chemical and microbial properties measured at the end of the experiment. Severe water stress did significantly decrease the height, number of leaves, and aboveground biomass of millet plants. Additionally, respiration, nematofauna trophic structure and abundance decreased as water stress increased. Lastly, bacterial feeders and plant parasitic nematodes were the most sensitive to severe water stress while fungal feeding nematodes remained unaffected. The results suggested that the intensity of water stress had more negative effects on soil basal respiration rather than soil microbial biomass.展开更多
Salinity is a major problem that seriously impacts agricultural production, particularly that of tomato (Solanum lycopersicum L.). However, the plant has the ability to associate with Arbuscular Mycorrhizal Fungi to b...Salinity is a major problem that seriously impacts agricultural production, particularly that of tomato (Solanum lycopersicum L.). However, the plant has the ability to associate with Arbuscular Mycorrhizal Fungi to better tolerate salt stress. Thus, thanks to the extension of the AMF hyphae, the hydromineral nutrition and the tolerance to excess toxic ions (Na<sup>+</sup> and Cl<sup>-</sup>) of the plant are optimized. In this context, the contribution of AMF to the salt stress tolerance of two tomato varieties under semi-controlled conditions was studied. To do this, the frequency and intensity of mycorrhization, the relative mycorrhizal dependency, the survival rates, the aerial and root dry weights, the mineral (P, K<sup>+</sup>, Na<sup>+</sup>) and proline contents of the plants subjected to four levels of salinity [0, 70, 140 and 210 mM of NaCl] were evaluated. All the parameters assessed appeared to be dependent on the variety, the fungal strain and the NaCl concentration. With the Lady Nema variety, inoculation with the Claroideoglomus etunicatum strain at [NaCl 140 mM] resulted in the highest frequencies (54%), intensities (40.47%), and relative mycorrhizal dependencies (19.65%). This same symbiotic couple recorded high survival rates (55%) and aerial (2.03 g) and root (0.50 g) dry weights. Significant contents of K<sup>+ </sup>(Leaves: 7.5 mg⋅g<sup>-1</sup>;Roots: 4.4 mg⋅g<sup>-1</sup> of dry matter), P (Leaves: 15.15 mg⋅g-1</sup> of dry matter) and proline (975 nmoles⋅g-1</sup> of fresh matter) were also recorded by this pair, with the lowest Na<sup>+</sup> contents (Leaves: 1.93 mg⋅g-1</sup>;Roots: 0.96 mg⋅g-1</sup> of dry matter). For the Mongal variety, at [NaCl 140 mM], the highest frequencies (50.36%), intensities (35.14%) and relative mycorrhizal dependencies (43.95%) were obtained thanks to inoculation with Rhizophagus fasciculatus. The highest survival rates (59%) and aerial (2.58 g) and root (0.79 g) dry weights were also obtained with this symbiotic couple. The contents of K<sup>+</sup> (Leaves: 6.1 mg⋅g-1</sup>;Roots: 3.09 mg⋅g-1 </sup>of dry matter), P (Leaves: 12.49 mg⋅g-1</sup> of dry matter) and proline (942 nmoles⋅g-1</sup> of fresh matter) the most important and those in Na<sup>+</sup> the lowest (Leaves: 2.03 mg⋅g-1</sup>;Roots: 1.53 mg⋅g-1</sup> of dry matter) were also recorded for this same pair. Thus, the best fungal partner for the Lady Nema variety is C. etunicatum, followed by F. mosseae and R. fasciculatus, while for the Mongal variety it is R. fasciculatus, followed by C. etunicatum and F. mosseae.展开更多
In the mobile radio industry, planning is a fundamental step for the deployment and commissioning of a Telecom network. The proposed models are based on the technology and the focussed architecture. In this context, w...In the mobile radio industry, planning is a fundamental step for the deployment and commissioning of a Telecom network. The proposed models are based on the technology and the focussed architecture. In this context, we introduce a comprehensive single-lens model for a fourth generation mobile network, Long Term Evolution Advanced Network (4G/LTE-A) technology which includes three sub assignments: cells in the core network. In the resolution, we propose an adaptation of the Genetic Evolutionary Algorithm for a global resolution. This is a combinatorial optimization problem that is considered as difficult. The use of this adaptive method does not necessarily lead to optimal solutions with the aim of reducing the convergence time towards a feasible solution.展开更多
Agroecosystems in the Senegalese groundnut basin experience long periods of high temperatures and drought, which disrupt the stability of soil microbial communities. This study evaluated how that stability is affected...Agroecosystems in the Senegalese groundnut basin experience long periods of high temperatures and drought, which disrupt the stability of soil microbial communities. This study evaluated how that stability is affected by homefields and outfields’ agricultural practices and the duration of heat stress. Specifically, we collected soils from organically farmed fields that receive continual high inputs of manure (homefields), and from fields that are rarely manured (outfields). Soil samples were submitted to artificial heat stress at 60°C for 3, 14, and 28 days, followed by 28 days of recovery at 28°C. We examined the functional stability of microbial communities by quantifying C mineralization, and characterized the stability of the communities’ taxonomic compositions via high-throughput DNA sequencing. We found that the microbial communities have a low resistance to heat stress in soils from both types of fields. However, the manuring practice does affect how the functional stability of microbial communities responds to different durations of heat stress. Although functional stability was not recovered fully in either soil, microbial community resilience seemed to be greater in homefield soils. Differences in manuring practices also affected the structural taxonomic stability of microbial communities: relative abundances of Bacilli, Chloroflexia, Actinobacteria and Sordariomycetes increased in the homefield stressed-soils, but decreased significantly in outfield soils. In contrast, relative abundances of α-Proteobacteria, γ-Proteobacteria and Eurotiomycetes increased significantly in outfield stressed-soils, while decreasing significantly in the homefield soils. Relative abundances of Bacilli changed little in outfield soils, indicating that this taxon is resistant to heat stress. In summary, the microbial communities’ capacities to resist heat stress and recover from it depend upon the organic richness of the soil (i.e., manuring practice) and the adaptation of soil microbes to environmental conditions.展开更多
In arid and semi-arid regions, the growth and development of cultivated plants, especially tomato (Solanum lycopersicum L.), are severely limited by water deficit. Thus, to cope with this constraint, the plant establi...In arid and semi-arid regions, the growth and development of cultivated plants, especially tomato (Solanum lycopersicum L.), are severely limited by water deficit. Thus, to cope with this constraint, the plant establishes symbiotic relationships with arbuscular mycorrhizal fungi (AMF) in the soil whose extension of the hyphae allows a better and deeper exploration;this notably improves the hydromineral nutrition of the plant. Therefore, the choice of fungal partner becomes crucial for the establishment of a crop in water-deficient soil. In this context, the contribution of AMF to the water stress tolerance of two varieties of tomato plants was assessed under semi-controlled conditions. Parameters, such as the mycorrhizal frequency, intensity of mycorrhization, relative mycorrhizal dependency, growth, and biochemical parameters (carbon, nitrogen, phosphorus, and proline contents) of plants subjected to three levels of water stress (T100, T70, and T30), were evaluated. The highest frequencies and intensities of mycorrhization and relative mycorrhizal dependencies were obtained with plants of the Xewel variety inoculated with Rhizophagus fasciculatus (F: 95.24%, 88.35%, and 13.64%;M: 40.52%, 37.52%, and 11.22%;D: 23.7%, 54.4%, and 78.82%) and in those of the Lady Nema variety inoculated with Claroideoglomus etunicatum (F: 95.12%, 87.01%, and 15.25%;M: 40.66%, 37.99%, and 11.42%;D: 19.27%, 57.01%, and 70.98%), respectively at water regimes of T100, T70 and T30. These same symbiotic couples recorded, at T30, the best survival rates (+ 40%) and the higher aerial (77% and 74%) and root dry weights (80% and 59%). Plants of the Xewel variety inoculated with R. fasciculatus recorded the highest contents of carbon (T70: 30.59% and T30: 21.55%) and phosphorus (T70: 0.18% and T30: 0.17%). Plants of the Lady Nema variety recorded the highest nitrogen contents with 3.51% and 3.20%, respectively at T70 and T30. Plants of the Lady Nema variety, inoculated with C. etunicatum, also recorded the highest proline contents (572.25, 739.44, and 1165 nmoles•g<sup>−1</sup> of fresh material), followed by those of the Xewel variety inoculated with R. fasciculatus (580.36, 763.65, and 1112.11 nmoles•g<sup>−1</sup> of fresh matter), respectively at T100, T70, and T30. For the Lady Nema variety, the best fungal partner is C. etunicatum, followed by R. fasciculatus and, finally, Funneliformis mosseae. However, for the plants of the Xewel variety, R. fasciculatus is the most efficient, followed by F. mosseae and C. etunicatum. This suggests that, in tomatoes, the efficiency of mycorrhizal symbiosis under water stress conditions is not only dependent on the host plant but on both associated symbiotic partners. Hence, it is a need for screening to identify the best symbiotic couples in a stressful environment.展开更多
The Paraiba do Sul(PSR)and Guandu Rivers(GR)water diversion system(120 km long)is located in the main industrial pole of Brazil and supplies drinking water for 9.4 million people in the metropolitan region of Rio de J...The Paraiba do Sul(PSR)and Guandu Rivers(GR)water diversion system(120 km long)is located in the main industrial pole of Brazil and supplies drinking water for 9.4 million people in the metropolitan region of Rio de Janeiro.This study aims to discern the trace metals dynamics in this complex aquatic system.We used a combined approach of geochemical tools such as geochemical partitioning,Zn isotopes signatures,and multivariate statistics.Zinc and Pb concentrations in Suspended Particulate Matter(SPM)and sediments were considerably higher in some sites.The sediment partition of As,Cr,and Cu revealed the residual fraction(F4)as the main fraction for these elements,indicating low mobility.Zinc and Pb were mostly associated with the exchangeable/carbonate(F1)and the reducible(F2)fractions,respectively,implying a higher susceptibility of these elements to being released from sediments.Zinc isotopic compositions of sediments and SPM fell in a binary mixing source process between lithogenic(δ^(66/64)Zn_(JMC)≈+0.30‰)and anthropogenic(δ^(66/64)Zn_(JMC)≈+0.15‰)end members.The lighterδ^(66/64)Zn_(JMC)values accompanied by high Zn concentrations in exchangeable/carbonate fraction(ZnF1)enable the tracking of Zn anthropogenic sources in the studied rivers.Overall,the results indicated that Hg,Pb,and Zn had a dominant anthropogenic origin linked to the industrial activities,while As,Cr,and Cu were mainly associated with lithogenic sources.This work demonstrates how integrating geochemical tools is valuable for assessing geochemical processes and mixing source effects in anthropized river watersheds.展开更多
基金Foundation items: the National Natural Science Foundation of China (10272001) the National Key Basic Research Special Foundation of China (G1998020302)
文摘A method is proposed for synthesizing output feedback controllers for nonlinear Lur' e systems . The problem of designing an output dynamic controller for uncertain-free systems and systems subject to multiplicative norm-bounded perturbations in the linear part were proposed respectively. The procedure is based on the use of the absolute stability, through the circle criterion, and a linear matrix inequalities (LAI) formulation. The controller existence conditions are given in terms of existence of suitable solutions to a set of parameter-dependent LMIs.
文摘The intrinsic physical properties of the noble metal nanoparticles,which are highly sensitive to the nature of their local molecular environment,make such systems ideal for the detection of molecular recognition events.The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles.In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization.A brief discussion of the three common methods of functionalization:Electrostatic adsorption;Chemisorption;Affinity-based coordination is given.In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition.In the main section the various types of capping agents for molecular recognition;nucleic acid coatings,protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications.Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition.For the proteins the recognition properties of antibodies form the core of the section.With respect to the supramolecular systems the cyclodextrins,calix[n]arenes,dendrimers,crown ethers and the cucurbitales are treated in depth.Finally a short section deals with the possible toxicity of the nanoparticles,a concern in public health.
文摘In Senegal, tomato (<i><span style="font-family:Verdana;">Solanum lycopersicum</span></i><span style="font-family:Verdana;"> L.) cultivation is affected by salinity in many agro-ecological zones. The selection of salt tolerant varieties would be an alternative solution to enhance the production. Thus, germination and growth are studied under axenic conditions for five varieties of tomato subjected to increasing concentrations of NaCl [0, 35, 70 and 105 mM], and supplemented in an MS/2 medium for 30 days. The results reveal that salt negatively affects the evaluated parameters. The </span><i><span style="font-family:Verdana;">Rodeo</span></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Lady Nema </span></i><span style="font-family:Verdana;">varieties have the lowest final germination rates (50%) unlike the </span><i><span style="font-family:Verdana;">Mongal</span></i><span style="font-family:Verdana;"> variety (55%). These last two varieties have a decrease of 71.78% and 81.28% in the height of the stem, respectively, in the presence of NaCl at [105 mM] while that of the </span><i><span style="font-family:Verdana;">Rodeo</span></i><span style="font-family:Verdana;"> variety is 70%. The </span><i><span style="font-family:Verdana;">Xewel</span></i><span style="font-family:Verdana;"> variety has the greatest average number of leaves in the presence of [NaCl 35 mM] (4.95 leaves) and [NaCl 70 mM] (4.77 leaves). The </span><i><span style="font-family:Verdana;">Lady Nema</span></i><span style="font-family:Verdana;"> variety records the longest taproot length (2.99 cm) unlike the </span><i><span style="font-family:Verdana;">Rodeo</span></i><span style="font-family:Verdana;"> variety (2.25 cm) at [NaCl 105 mM]. The </span><i><span style="font-family:Verdana;">Ganila</span></i><span style="font-family:Verdana;"> variety reveals the highest number of secondary roots at the concentrations of [0, 35 and 105 mM] of NaCl with, respectively, 44.12, 29.25, and 4.25 roots. The </span><i><span style="font-family:Verdana;">Lady Nema</span></i><span style="font-family:Verdana;"> variety records the highest fresh weight of aerial (0.055 g) and root parts (0.014 g) and the lowest root dry weights (0.0023 g). These results allow to conclude that the </span><i><span style="font-family:Verdana;">Lady Nema </span></i><span style="font-family:Verdana;">and</span><i><span style="font-family:Verdana;"> Mongal</span></i><span style="font-family:Verdana;"> varieties seem more tolerant, </span><i><span style="font-family:Verdana;">Ganila </span></i><span style="font-family:Verdana;">and</span><i><span style="font-family:Verdana;"> Xewel</span></i><span style="font-family:Verdana;"> are moderately tolerant and </span><i><span style="font-family:Verdana;">Rodeo</span></i><span style="font-family:Verdana;"> is more sensitive to the presence of salt.</span>
文摘Fast recovery and minimum utilization of resources are the two main criteria for determining the protection scheme quality. We address the problem of providing a hybrid protection approach on elastic optical networks under contiguity and continuity of available spectrum constraints. Two main hypotheses are used in this paper for backup paths computation. In the first case, it is assumed that backup paths resources are dedicated. In the second case, the assumption is that backup paths resources are available shared resources. The objective of the study is to minimize spectrum utilization to reduce blocking probability on a network. For this purpose, an efficient survivable Hybrid Protection Lightpath （HybPL） algorithm is proposed for providing shared or dedicated backup path protection based on the efficient energy calculation and resource availability. Traditional First-Fit and Best-Fit schemes are employed to search and assign the available spectrum resources. The simulation results show that HybPL presents better performance in terms of blocking probability, compared with the Minimum Resources Utilization Dedicated Protection （MRU-DP） algorithm which offers better performance than the Dedicated Protection （DP） algorithm.
文摘Bambara groundnut [Vigna subterranean (L.) Verdc] is a food legume with high potential for food security in Sub-Saharan Africa. However, in addition to being a neglected crop, its production is limited by several constraints among which viral diseases are most cited. In order to contribute to the improvement of Bambara groundnut in Burkina Faso, local accessions of the crop were screened for resistance to Cowpea mottle virus (CPMoV), one of the most damaging viruses in grain legumes. Seven local accessions (C1 to C7) from two agro-ecological zones were evaluated by mechanical inoculation in field conditions in 2016 and 2017. The infected plants exhibited various symptoms of chlorosis, leaf deformation, growth retardation and plant stunting. CPMoV caused a significant reduction in the number of flowers and pods. As a result, grain yield was reduced by 49.5% to 83.9% depending on the accessions. The impact of the virus in yield loss was lowest in accessions C6 and C7 which indicated their possible used in the management of Cowpea mottle virus disease in bambara groundnut.
文摘<i><span style="font-family:"">Annona</span></i><span style="font-family:""> <i>muricata</i> L. and <i>Annona</i> <i>squamosa</i> L. are tropical species whose</span><span style="font-family:""> fleshy fruit is edible. They offer real possibilities for socio-economic use, particularly in the fields of medicine, nutrition, ecosystem conservation and the poverty alleviation. This study was set up to evaluate different methods of micropropagation from juvenile material for the regeneration of these species. Thus, MS medium supplemented with [BAP 2 mg·L<sup>-1</sup>] <i>i.e.</i> M2 produced 2.87 newly <span>formed shoots from the cotyledonary nodes of <i>A.</i> <i>muricata</i>. For the terminal apices of <i>A.</i> <i>squamosa</i>, it was MMS medium supplemented with [BAP 2</span> mg·L<sup>-1</sup>] <i>i.e.</i> MM2 that was most conducive to new shoot formation (3.12). The addition of 0.1 and 0.2 mg·L<sup>-1</sup> of NAA in the M2 medium, made it possi<span>ble to have the best elongations and average number of nodes for the new shoots from cotyledonary nodes of <i>A.</i> <i>muricata</i> (9.11 cm for 5.62 nodes). With <i>A.</i> <i>squamosa</i>, MM7 medium [MMS + BAP 1 mg·L<sup>-1</sup></span></span><span style="font-family:""> </span><span style="font-family:"">+ KIN 1 mg·L<sup>-1</sup>]</span><span style="font-family:""> resulted in an average length of 9.05 cm with 5.62 nodes on average for the apical shoots. A 3-day rhizogenic induction period in the dark with [IBA 50 mg·L<sup>-1</sup>] and 2 g·L<sup>-1</sup> of activated charcoal gave a rooting rate of 66.67% for shoots originating from the cotyledonary nodes of <i>A.</i> <i>squamosa</i>;while with vitroplants from cotyledonary nodes of <i>A.</i> <i>muricata</i>, a better rooting rate (83.33%) was obtained following a 5-day rhizogenic induction. After 30 days of acclimatization, the survival rate reached 83.33% for plants from the tips of <i>A.</i> <i>muricata</i>, whereas for <i>A.</i> <i>squamosa,</i> it was plants grown from cotyledonary nodes that had the same survival rate.
文摘Water is the main limiting factor in the cultivation of tomato (<i>Solanum lyco<span>persicum</span></i><span> L.) in Senegal. Thus, the selection of varieties tolerant to water st</span>ress would be an alternative solution for their production. <i>In vitro </i>germination, growth, total chlorophyll and proline levels were studied in five varieties of tomato subjected to increasing osmotic pressures (0, 5, 10 and 15 kPa) thanks to the PEG-8000 incorporated in an MS/2 medium for 30 days. A strong sen<span>sitivity to water stress for <i>in vitro</i> seed germination in the <i>Rodeo</i> variety (4</span>1%) is recorded at 5 kPa and maintained at 15 kPa (20.83%) while it was only noticed at 15 kPa in the other tomato varieties. The <i>Xewel</i> and <i>Lady Nema</i> varieties obtained the smallest reductions in the number of leaves of vitroplants, with 30.79% and 27.97% at 15 kPa, respectively, and the <i>Rodeo</i> variety recorded a reduction of 35.97%. From 5 kPa, the varieties record reductions in <span>the number of secondary roots of more than 15%. The effect of osmotic pr</span>essures on decreasing the taproot height and length is not significant. The <i>Xewel </i>variety had the highest average fresh (0.483 g) and dry (0.082 g) weights of the aerial part at 15 kPa and the <i>Rodeo</i> variety </span><span style="font-family:"">had </span><span style="font-family:"">the lowest ones (0.308 g and 0.0501 g). The <i>Lady Nema</i> variety had the highest average fresh (0.171 g) and dry (0.039 g) root weights and the <i>Rodeo</i> variety</span><span style="font-family:""> had</span><span style="font-family:""> the lowest ones (0.086 and 0.020 g). The vitroplants of <i>Rodeo </i>variety recorded the highest decreases in total chlorophyll contents at all osmotic pressures and the lowest increase in proline content (53.37%) at 15 kPa. <i>A contrario</i>, the <i>Xewel</i> variety recorded the greatest increase in proline content (116.26%). Ultimately, the vitroplants of <i>Lady Nem</i>a and <i>Xewe</i>l varieties were more tolerant to water stress, the <i>Ganila </i>and<i> Mongal </i>varieties were moderately tolerant and the <i>Rodeo</i> variety was the most sensitive.
文摘Imperata yellow mottle caused by Imperata yellow mottle virus (IYMV) of the genus Sobemovirus was first characterized on Imperata cylindrical and Zea mays in Burkina Faso. The disease has been reported in several localities of the country but its ecology and epidemiology are poorly known. In particular, only I. cylindrical and maize have been reported within IYMV host range. The aim of this study was to investigate the experimental host range of the virus. Mechanical inoculation of a mixture of four IYMV isolates to 18 plant species, including four crops (maize, rice, sorghum and pearl millet) and 14 wild grasses showed clear mottle symptoms in maize, sorghum and pearl millet and two wild grass species (Setaria verticillata and Rottboellia exaltata). Symptom development was confirmed by Enzyme-linked immunosorbent assay and reverse transcription–polymerase chain reaction (RT-PCR). Infection of crop species by IYMV depended on cultivars tested. Therefore, proportions of positive cultivars were 16/36 in maize, 4/10 in sorghum and 4/9 in pearl millet, respectively. Studies on virus-host interactions using individual virus isolates showed two pathogenic patterns. Three out of the four isolates tested infected all plant species and cultivars. In contrast, the fourth IYMV isolate could infect only one maize cultivar. These results expand the previously known host range of IYMV from two to five species, indicating a narrow host range. Among the new characterized host species, sorghum and pearl millet are important cereal crops. Therefore, Imperata yellow motte disease is a potential threat for the cereal crop production and its ecology and epidemiology should be thoroughly investigated.
文摘Potyviruses are major constraints to grain legume production by causing significant yield losses. Potyviruses infecting Bambara groundnut (Vigna subterranea) were investigated in Burkina Faso. Leaf samples collected from three agroclimatic zones were subjected to RT-PCR and sequence analyses. Of a total of 135 samples, 36 (26.67%) were detected positive in RT-PCR tests using potyvirus universal primers. Analysis of full coat protein (cp) sequences from 24 isolates revealed the occurrence of three groups of Bambara groundnut-infecting potyviruses. Virus isolates in group 1 shared 94.5% - 100% nucleotide (nt) identity with CABMV whereas those in group 2 and group 3 were distantly related Bean common necrosis virus (BCMNV) and Passiflora virus Ugandan which were their respective closest potyviruses. Group 2 shared 77.1% nt and 78.8% - 79.9% aa identity with BCMNV and group 3 shared 77.3% - 78.3% nt and 80.7% - 81.5% aa identity with Passiflora virus Ugandan. All three groups were confirmed by phylogenetic analyses. Taking into account potyvirus demarcation criteria, group 1 isolates belonged to CABMV species. Group 2 and group 3 were assigned to a potentially new potyviruses species and designated Bambara groundnut potyvirus 1 (BGPV1) and Bambara groundnut potyvirus 2 (BGPV2).
文摘Imperata yellow mottle virus (IYMV, Sobemovirus) was first described in 2008 in the south-western region of Burkina Faso (West Africa). The genetic diversity of IYMV was not documented up to day. In this study, the variability of CP of IYMV was evaluated through the molecular characterization of 38 isolates collected in the western part of Burkina Faso. Comparison of sequences of these new isolates and one IYMV sequence available in GenBank revealed that the average nucleotide diversity was low. The ratio of non-synonymous over synonymous nucleotide substitutions per site was low, indicating a CP diversification under strong purifying selection. Despite of the low nucleotide diversity, phylogenetic analyses revealed segregation of IYMV isolates into six major clades. There was no correlation of phylogenetic grouping of isolates based on geographical location. This is the first study of the genetic diversity of IYMV.
文摘Satellite precipitation products are widely used in different domain, in area where there is a lack in observation. These have different spatio-temporal resolutions consequently resulting in different precipitation amounts depending on the product. The present study validates three satellite products, namely the Climate Hazard group Infrared Precipitation with Stations (CHIRPS), the Climate Research Unit (CRU) and the Global Precipitation Climatology Project (GPCP) over Bandama and Mono river basins for 1981-2005 and 1981-2016 respectively by comparing them to the observation precipitation of the basin. The available studies are focused on the regional scale but not on a watershed scale for hydrological studies. The analysis reveals that all the products are strongly correlated to each other as well as to the observed data at basin level. The Lamb coefficient test shows that most all the chosen basin namely Bandama and Mono presents the same climatic indices. All the products present the same variability and trend as the observation at basins scale. By comparing those products to observation, CHIRPS product following by GPCP give the lowest mean absolute error (MAE) at annual and seasonal time scales while CHIRPS is followed by CRU at monthly scale. Overall, all products overestimate the precipitation at Bandama basin while they underestimate it over Mono river basin. The comparison over 1981-2017 period of the total annual precipitation increasing southern ward (from Sahel to the coastal zone) for all the three studied products which varies from 300 mm to 2400 mm/year. All the three products are not significantly different from one another and they all highlight the same areas of hotspot rainfall in the region. The same conclusion is made at monthly and seasonal scales. Therefore, any of these products especially CHIRPS can be used for study in this region due to its lowest bias and MAE.
文摘Annona senegalensis is a savannah species present in the wild in tropical and sub-tropical African regions. It is used by the local populations for its many economic, pharmacological, nutritional and ecological interests. However, the strong pressure exerted on this species as well as the increasing degradation of the ecosystems, in which it evolves, seriously compromise its sustainability and development. Conventional methods of vegetative propagation are not sufficient to ensure its durable regeneration and the renewal of endemic populations in Senegal. In this context, it was undertaken in vitro propagation, from 30 days old juvenile seedlings. Thus, axillary, cotyledonary and apical nodes were in vitro cultured in Murashige and Skoog (1962) medium (MS), with different concentrations of cytokinins and/or auxins. BAP used alone at 2 mg•L<sup>−1</sup> proved to be more beneficial for micropropagation of different types of explants compared to Kinetin used alone or in combination with BAP, especially for axillary and cotyledonary nodes. The BAP-NAA combination allowed to have a better elongation of newly formed shoots. For shoots of apical and cotyledonary nodes origin, a rhizogenic induction of 5 days, with IBA at 25 mg•L<sup>−1</sup>, resulted in a better rooting rate with, respectively, 75% (for 2.22 roots) and 66.67% (for 4.17 roots). For newly formed shoots of axillary origin, a 24-hour rooting induction with IBA at 50 mg•L<sup>−1</sup> gave a rooting rate of 58.33% (for 2.4 roots). After 30 days of acclimatization, the survival rate was 75% for the young plants from the apices and 83.33% for those originating from the cotyledonary and axillary nodes. This protocol can therefore be adopted for the in vitro clonal propagation of A. senegalensis juvenile material.
文摘Drought stress strongly affects soil biota and impairs crop production, which under climate change will be exacerbated in semi-arid cropping regions such as the Sahel. Hence soil management systems are needed that can buffer against drought. In West Africa, field studies have found intercropping of millet with the native shrub Piliostigma reticulatum improves soil-plant-water relations, microbial activity and diversity, and suppress parasitic nematodes, which can significantly increase crop yield. However, little information is available on its beneficial or negative effects on soils or crops during water stress. Therefore, the objective was to investigate the impact of P. reticulatum in moderating water stress effects on soil properties and pearl millet (Pennisetum glaucum [L.] R. Br.) productivity. In the greenhouse, soil chemical and microbial properties and millet growth were investigated with a factorial experiment of varying levels of soil moisture (favorable, moderately stressed, or severely stressed water conditions) that was imposed for 55 days on soils containing sole P. reticulatum or millet, or millet + P. reticulatum. The results showed that the presence of P. reticulatum did not buffer soils against water stress in relation to soil chemical and microbial properties measured at the end of the experiment. Severe water stress did significantly decrease the height, number of leaves, and aboveground biomass of millet plants. Additionally, respiration, nematofauna trophic structure and abundance decreased as water stress increased. Lastly, bacterial feeders and plant parasitic nematodes were the most sensitive to severe water stress while fungal feeding nematodes remained unaffected. The results suggested that the intensity of water stress had more negative effects on soil basal respiration rather than soil microbial biomass.
文摘Salinity is a major problem that seriously impacts agricultural production, particularly that of tomato (Solanum lycopersicum L.). However, the plant has the ability to associate with Arbuscular Mycorrhizal Fungi to better tolerate salt stress. Thus, thanks to the extension of the AMF hyphae, the hydromineral nutrition and the tolerance to excess toxic ions (Na<sup>+</sup> and Cl<sup>-</sup>) of the plant are optimized. In this context, the contribution of AMF to the salt stress tolerance of two tomato varieties under semi-controlled conditions was studied. To do this, the frequency and intensity of mycorrhization, the relative mycorrhizal dependency, the survival rates, the aerial and root dry weights, the mineral (P, K<sup>+</sup>, Na<sup>+</sup>) and proline contents of the plants subjected to four levels of salinity [0, 70, 140 and 210 mM of NaCl] were evaluated. All the parameters assessed appeared to be dependent on the variety, the fungal strain and the NaCl concentration. With the Lady Nema variety, inoculation with the Claroideoglomus etunicatum strain at [NaCl 140 mM] resulted in the highest frequencies (54%), intensities (40.47%), and relative mycorrhizal dependencies (19.65%). This same symbiotic couple recorded high survival rates (55%) and aerial (2.03 g) and root (0.50 g) dry weights. Significant contents of K<sup>+ </sup>(Leaves: 7.5 mg⋅g<sup>-1</sup>;Roots: 4.4 mg⋅g<sup>-1</sup> of dry matter), P (Leaves: 15.15 mg⋅g-1</sup> of dry matter) and proline (975 nmoles⋅g-1</sup> of fresh matter) were also recorded by this pair, with the lowest Na<sup>+</sup> contents (Leaves: 1.93 mg⋅g-1</sup>;Roots: 0.96 mg⋅g-1</sup> of dry matter). For the Mongal variety, at [NaCl 140 mM], the highest frequencies (50.36%), intensities (35.14%) and relative mycorrhizal dependencies (43.95%) were obtained thanks to inoculation with Rhizophagus fasciculatus. The highest survival rates (59%) and aerial (2.58 g) and root (0.79 g) dry weights were also obtained with this symbiotic couple. The contents of K<sup>+</sup> (Leaves: 6.1 mg⋅g-1</sup>;Roots: 3.09 mg⋅g-1 </sup>of dry matter), P (Leaves: 12.49 mg⋅g-1</sup> of dry matter) and proline (942 nmoles⋅g-1</sup> of fresh matter) the most important and those in Na<sup>+</sup> the lowest (Leaves: 2.03 mg⋅g-1</sup>;Roots: 1.53 mg⋅g-1</sup> of dry matter) were also recorded for this same pair. Thus, the best fungal partner for the Lady Nema variety is C. etunicatum, followed by F. mosseae and R. fasciculatus, while for the Mongal variety it is R. fasciculatus, followed by C. etunicatum and F. mosseae.
文摘In the mobile radio industry, planning is a fundamental step for the deployment and commissioning of a Telecom network. The proposed models are based on the technology and the focussed architecture. In this context, we introduce a comprehensive single-lens model for a fourth generation mobile network, Long Term Evolution Advanced Network (4G/LTE-A) technology which includes three sub assignments: cells in the core network. In the resolution, we propose an adaptation of the Genetic Evolutionary Algorithm for a global resolution. This is a combinatorial optimization problem that is considered as difficult. The use of this adaptive method does not necessarily lead to optimal solutions with the aim of reducing the convergence time towards a feasible solution.
文摘Agroecosystems in the Senegalese groundnut basin experience long periods of high temperatures and drought, which disrupt the stability of soil microbial communities. This study evaluated how that stability is affected by homefields and outfields’ agricultural practices and the duration of heat stress. Specifically, we collected soils from organically farmed fields that receive continual high inputs of manure (homefields), and from fields that are rarely manured (outfields). Soil samples were submitted to artificial heat stress at 60°C for 3, 14, and 28 days, followed by 28 days of recovery at 28°C. We examined the functional stability of microbial communities by quantifying C mineralization, and characterized the stability of the communities’ taxonomic compositions via high-throughput DNA sequencing. We found that the microbial communities have a low resistance to heat stress in soils from both types of fields. However, the manuring practice does affect how the functional stability of microbial communities responds to different durations of heat stress. Although functional stability was not recovered fully in either soil, microbial community resilience seemed to be greater in homefield soils. Differences in manuring practices also affected the structural taxonomic stability of microbial communities: relative abundances of Bacilli, Chloroflexia, Actinobacteria and Sordariomycetes increased in the homefield stressed-soils, but decreased significantly in outfield soils. In contrast, relative abundances of α-Proteobacteria, γ-Proteobacteria and Eurotiomycetes increased significantly in outfield stressed-soils, while decreasing significantly in the homefield soils. Relative abundances of Bacilli changed little in outfield soils, indicating that this taxon is resistant to heat stress. In summary, the microbial communities’ capacities to resist heat stress and recover from it depend upon the organic richness of the soil (i.e., manuring practice) and the adaptation of soil microbes to environmental conditions.
文摘In arid and semi-arid regions, the growth and development of cultivated plants, especially tomato (Solanum lycopersicum L.), are severely limited by water deficit. Thus, to cope with this constraint, the plant establishes symbiotic relationships with arbuscular mycorrhizal fungi (AMF) in the soil whose extension of the hyphae allows a better and deeper exploration;this notably improves the hydromineral nutrition of the plant. Therefore, the choice of fungal partner becomes crucial for the establishment of a crop in water-deficient soil. In this context, the contribution of AMF to the water stress tolerance of two varieties of tomato plants was assessed under semi-controlled conditions. Parameters, such as the mycorrhizal frequency, intensity of mycorrhization, relative mycorrhizal dependency, growth, and biochemical parameters (carbon, nitrogen, phosphorus, and proline contents) of plants subjected to three levels of water stress (T100, T70, and T30), were evaluated. The highest frequencies and intensities of mycorrhization and relative mycorrhizal dependencies were obtained with plants of the Xewel variety inoculated with Rhizophagus fasciculatus (F: 95.24%, 88.35%, and 13.64%;M: 40.52%, 37.52%, and 11.22%;D: 23.7%, 54.4%, and 78.82%) and in those of the Lady Nema variety inoculated with Claroideoglomus etunicatum (F: 95.12%, 87.01%, and 15.25%;M: 40.66%, 37.99%, and 11.42%;D: 19.27%, 57.01%, and 70.98%), respectively at water regimes of T100, T70 and T30. These same symbiotic couples recorded, at T30, the best survival rates (+ 40%) and the higher aerial (77% and 74%) and root dry weights (80% and 59%). Plants of the Xewel variety inoculated with R. fasciculatus recorded the highest contents of carbon (T70: 30.59% and T30: 21.55%) and phosphorus (T70: 0.18% and T30: 0.17%). Plants of the Lady Nema variety recorded the highest nitrogen contents with 3.51% and 3.20%, respectively at T70 and T30. Plants of the Lady Nema variety, inoculated with C. etunicatum, also recorded the highest proline contents (572.25, 739.44, and 1165 nmoles•g<sup>−1</sup> of fresh material), followed by those of the Xewel variety inoculated with R. fasciculatus (580.36, 763.65, and 1112.11 nmoles•g<sup>−1</sup> of fresh matter), respectively at T100, T70, and T30. For the Lady Nema variety, the best fungal partner is C. etunicatum, followed by R. fasciculatus and, finally, Funneliformis mosseae. However, for the plants of the Xewel variety, R. fasciculatus is the most efficient, followed by F. mosseae and C. etunicatum. This suggests that, in tomatoes, the efficiency of mycorrhizal symbiosis under water stress conditions is not only dependent on the host plant but on both associated symbiotic partners. Hence, it is a need for screening to identify the best symbiotic couples in a stressful environment.
基金partly funded by the LMI-OCE and CNPq 400029/2015-4,420697/2018-7Jeremie Garnier was supported by CNPq grant 302722/2018-1。
文摘The Paraiba do Sul(PSR)and Guandu Rivers(GR)water diversion system(120 km long)is located in the main industrial pole of Brazil and supplies drinking water for 9.4 million people in the metropolitan region of Rio de Janeiro.This study aims to discern the trace metals dynamics in this complex aquatic system.We used a combined approach of geochemical tools such as geochemical partitioning,Zn isotopes signatures,and multivariate statistics.Zinc and Pb concentrations in Suspended Particulate Matter(SPM)and sediments were considerably higher in some sites.The sediment partition of As,Cr,and Cu revealed the residual fraction(F4)as the main fraction for these elements,indicating low mobility.Zinc and Pb were mostly associated with the exchangeable/carbonate(F1)and the reducible(F2)fractions,respectively,implying a higher susceptibility of these elements to being released from sediments.Zinc isotopic compositions of sediments and SPM fell in a binary mixing source process between lithogenic(δ^(66/64)Zn_(JMC)≈+0.30‰)and anthropogenic(δ^(66/64)Zn_(JMC)≈+0.15‰)end members.The lighterδ^(66/64)Zn_(JMC)values accompanied by high Zn concentrations in exchangeable/carbonate fraction(ZnF1)enable the tracking of Zn anthropogenic sources in the studied rivers.Overall,the results indicated that Hg,Pb,and Zn had a dominant anthropogenic origin linked to the industrial activities,while As,Cr,and Cu were mainly associated with lithogenic sources.This work demonstrates how integrating geochemical tools is valuable for assessing geochemical processes and mixing source effects in anthropized river watersheds.
