Nematode distribution and damage to yam in central and eastern Uganda

Yams (Dioscorea spp.) are food crops of growing significance in sub Saharan Africa. Unfortunately, nematodes are major pests to their production. A study was undertaken in major yam growing areas of Uganda to investigate the association of plant parasitic nematodes with damage symptoms. Nematodes were assessed from tubers, roots and surrounding soil for seven cultivars belonging to Dioscorea alata, D. bulbisiana, D. burkilliana and D. cayenensis at harvest. Pratylenchus sudanensis was found in the greatest density and was followed byMeloidogyne spp. Higher densities of both nematodes were observed in the tubers rather than roots. Although symptoms of cracking and galling were relatively low, P. sudanensis incidence was strongly associated with cracking and Meloidogyne spp. with galling. Pratylenchus sudanensis and Meloidogyne spp. incidence their associated damage were, however, negatively correlated, suggesting inter-species competition. Principal components analysis of data suggested that differences in susceptibility to P. sudanensis occur between yam cultivars and species

Combined exome and whole-genome sequencing identifies mutations in ARMC4 as a cause of primary ciliary dyskinesia with defects in the outer dynein arm

Primary ciliary dyskinesia (PCD) is a rare, genetically heterogeneous ciliopathy disorder affecting cilia and sperm motility. A range of ultrastructural defects of the axoneme underlie the disease, which is characterised by chronic respiratory symptoms and obstructive lung disease, infertility and body axis laterality defects. We applied a next-generation sequencing approach to identify the gene responsible for this phenotype in two consanguineous families

Nematode distribution and damage to yam in Central and Eastern Uganda

Yams (Dioscorea spp.) are food crops of growing significance in sub Saharan Africa. Unfortunately, nematodes are major pests to their production. A study was undertaken in major yam growing areas of Uganda to investigate the association of plant parasitic nematodes with damage symptoms. Nematodes were assessed from tubers, roots and surrounding soil for seven cultivars belonging to Dioscorea alata, D. bulbisiana, D.burkilliana and D. cayenensis at harvest. Pratylenchus sudanensis was found in the greatest density and was followed by Meloidogyne spp. Higher densities of both nematodes were observed in the tubers rather than roots. Although symptoms of cracking and galling were relatively low, P. sudanensis incidence was strongly associated with cracking and Meloidogyne spp. with galling. Pratylenchus sudanensis and Meloidogyne spp. incidence their associated damage were, however, negatively correlated, suggesting inter-species competition. Principal components analysis of data suggested that differences in susceptibility to P. sudanensis occur between yam cultivars and species.Les ignames (Dioscorea spp.) sont une culture alimentaire d’importance croissante en Afrique sub–saharienne.Malheureusement, les nématodes sont des parasites majeurs qui gênent sa production. Une étude était menéedans les principales régions productrices de l’igname en Ouganda en vue de pouvoir mener investigation surl’association des nématodes parasitant les plantes avec les symptômes de dommages. Les nématodes étaientévalués à partir des racines, tubercules, et sol environnant pour 7 cultivars appartenant à Dioscorea alata, D.bulbisiana, D. burkilliana et D. cayenensis à la récolte. Pratylenchus sudanensis était considérée l’espèce à plushaute densité et était suivie par Meloidogyne spp. Des densités plus élevées des nématodes étaient observéesplus dans les tubercules que dans les racines. Bien que les symptômes de craquelures et d’irritations étaientrelativement bas, P.Sudanensis et Meloidogyne spp. étaient respectivement associées à la craquelure et à l’irritation.Pratylenctus Sudanensis et Meloidogyne spp. présentaient des damages associés, qui étaient cependant négativementcorrélés suggérant une compétition inter-espèces. L’analyse principale des données a suggéré des différences à lasusceptibilité du P. Sudanensis surviennent entre cultivars et espèces d’ignames

Electrochemical Stability and Postmortem Studies of Pt/SiC Catalysts for Polymer Electrolyte Membrane Fuel Cells

In the presented work, the electrochemical stability of platinized silicon carbide is studied. Postmortem transmission electron microscopy and X-ray photoelectron spectroscopy were used to document the change in the morphology and structure upon potential cycling of Pt/SiC catalysts. Two different potential cycle aging tests were used in order to accelerate the support corrosion, simulating start-up/shutdown and load cycling. On the basis of the results, we draw two main conclusions. First, platinized silicon carbide exhibits improved electrochemical stability over platinized active carbons. Second, silicon carbide undergoes at least mild oxidation if not even silicon leaching

Core-level XPS spectra of supported 3d-metal ultrathin layers : experimental and theoretical studies

In order to discuss the relation between the core level c-XPS spectra and the local electronic and magnetic properties of supported 3d transition metal atoms, we incorporate the various Coulomb and exchange interactions into a generalized impurity Anderson Hamiltonian, both in the initial state (Udd, Jdd) and final state (Udc, Jdc) of the c-XPS process. Then we discuss recent experimental 3s-XPS spectra of Fe and Co ultrathin-layers upon Cr(100) as well as V clusters upon graphite in terms of the two limits of the preceding Hamiltonian : (1) the exchange splitting limit (Jdc) and (2) the dielectric relaxation limit (Udc)

Equisingularity and Simultaneous Resolution of Singularities

Zariski defined equisingularity on an n-dimensional hypersurface V via stratification by "dimensionality type," an integer associated to a point by means of a generic local projection to affine n-space. A possibly more intuitive concept of equisingularity can be based on stratification by simultaneous resolvability of singularities. The two approaches are known to be equivalent for families of plane curve singularities. In higher dimension we ask whether constancy of dimensionality type along a smooth subvariety W of V implies the existence of a simultaneous resolution of the singularities of V along W. (The converse is false.) The underlying idea is to follow the classical inductive strategy of Jung -- begin by desingularizing the discriminant of a generic projection -- to reduce to asking if there is a canonical resolution process which when applied to quasi-ordinary singularities depends only on their characteristic monomials. This appears to be so in dimension 2. In higher dimensions the question i