Spectra of magnetic perturbations triggered by pellets in JET plasmas

Aiming at investigating edge localised mode (ELM) pacing for future application on ITER, experiments have been conducted on JET injecting pellets in different plasma configurations, including high confinement regimes with type-I and type-III ELMs, low confinement regimes and Ohmically heated plasmas. The magnetic perturbations spectra and the toroidal mode number, n, of triggered events are compared with those of spontaneous ELMs using a wavelet analysis to provide good time resolution of short-lived coherent modes. It is found that—in all these configurations—triggered events have a coherent mode structure, indicating that pellets can trigger an MHD event basically in every background plasma. Two components have been found in the magnetic perturbations induced by pellets, with distinct frequencies and toroidal mode numbers. In high confinement regimes triggered events have similarities with spontaneous ELMs: both are seen to start from low toroidal mode numbers, then the maximum measured n increases up to about 10 within 0.3 ms before the ELM burst

Characterization of hemizygous deletions in Citrus using array-Comparative Genomic Hybridization and microsynteny comparisons with the poplar genome

<p>Abstract</p> <p>Background</p> <p>Many fruit-tree species, including relevant <it>Citrus </it>spp varieties exhibit a reproductive biology that impairs breeding and strongly constrains genetic improvements. In citrus, juvenility increases the generation time while sexual sterility, inbreeding depression and self-incompatibility prevent the production of homozygous cultivars. Genomic technology may provide citrus researchers with a new set of tools to address these various restrictions. In this work, we report a valuable genomics-based protocol for the structural analysis of deletion mutations on an heterozygous background.</p> <p>Results</p> <p>Two independent fast neutron mutants of self-incompatible clementine (<it>Citrus clementina </it>Hort. Ex Tan. cv. Clemenules) were the subject of the study. Both mutants, named 39B3 and 39E7, were expected to carry DNA deletions in hemizygous dosage. Array-based Comparative Genomic Hybridization (array-CGH) using a <it>Citrus </it>cDNA microarray allowed the identification of underrepresented genes in these two mutants. Subsequent comparison of citrus deleted genes with annotated plant genomes, especially poplar, made possible to predict the presence of a large deletion in 39B3 of about 700 kb and at least two deletions of approximately 100 and 500 kb in 39E7. The deletion in 39B3 was further characterized by PCR on available <it>Citrus </it>BACs, which helped us to build a partial physical map of the deletion. Among the deleted genes, <it>ClpC</it>-like gene coding for a putative subunit of a multifunctional chloroplastic protease involved in the regulation of chlorophyll <it>b </it>synthesis was directly related to the mutated phenotype since the mutant showed a reduced chlorophyll <it>a</it>/<it>b </it>ratio in green tissues.</p> <p>Conclusion</p> <p>In this work, we report the use of array-CGH for the successful identification of genes included in a hemizygous deletion induced by fast neutron irradiation on <it>Citrus clementina</it>. The study of gene content and order into the 39B3 deletion also led to the unexpected conclusion that microsynteny and local gene colinearity in this species were higher with <it>Populus trichocarpa </it>than with the phylogenetically closer <it>Arabidopsis thaliana</it>. This work corroborates the potential of <it>Citrus </it>genomic resources to assist mutagenesis-based approaches for functional genetics, structural studies and comparative genomics, and hence to facilitate citrus variety improvement.</p

Evaluaci\uf3n de Metaphycus sp. (Hymenoptera: Encyrtidae) como agente de control natural de Capulinia sp. cercana a jaboticabae von Ihering (Hemiptera: Eriococcidae)

Geraud-Pouey F, Chirinos DT, Aguirre R, Bravo Y, Quintero JA. 2001. Evaluation of Metaphycus sp. (Hymenoptera: Encyrtidae) as agent of natural control of Capulinia sp. near of jaboticabae von Ihering (Hemiptera: Eriococcidae). Entomotropica 16(3):165-171. In Venezuela, since its appearance in 1993, Capulinia sp. is the most destructive pest on guava ( Psidium guajava L.). By early 1996 parasitism for Metaphycus sp. was detected. To evaluate its effect during March-May 1999 an assay under field conditions was conducted in Mara County, State of Zulia, Venezuela. Utilizing exclusion techniques, the treatments were evaluated: T1, guava branches completely exposed, T2, branches closed into organza cages and T3, branches into organza cages impregnated with insecticide. The populations of Capulinia were counted and the percentage of parasitism was estimated (expressed as parasitized female on female total). On T1, parasitism resulted highest (100%, P&lt;0.05), observing lower population mean (12.70 individual), whereas on T3, Capulinia reached its population maxim levels (200.5 individual) detecting 39.66% of parasitism. Thus, Metaphycus sp. resulted an important regulator factor on Capulinia populations during this period.Geraud-Pouey F, Chirinos DT, Aguirre R, Bravo Y, Quintero JA. 2001. Evaluaci\uf3n de Metaphycus sp. (Hymenoptera: Encyrtidae) como agente de control natural de Capulinia sp. cercana a jaboticabae von Ihering (Hemiptera: Eriococcidae). Entomotropica 16(3):165-171. En Venezuela, desde 1993, Capulinia sp. se ha convertido en la plaga de mayor importancia en el cultivo del guayabo ( Psidium guajava L.). A principios 1996 se detect\uf3 apreciable parasitismo por Metaphycus sp. Para evaluar su efecto, se realiz\uf3 un ensayo de campo durante los meses marzo-mayo 1999, en el municipio Mara, estado Zulia, Venezuela. Mediante la t\ue9cnica de exclusi\uf3n se evaluaron los tratamientos: T1, ramas de guayabo completamente expuestas, T2, ramas encerradas en jaulas de organza y T3, ramas en jaulas de organza impregnadas con insecticida. Se contaron las poblaciones de Capulinia y se estim\uf3 el porcentaje de parasitismo (expresado como hembras parasitadas del total de hembras). En T1, el parasitismo result\uf3 superior (100%, P&lt;0,05), observ\ue1ndose el menor promedio poblacional (12,70 individuos) mientras que en T3, Capulinia alcanz\uf3 sus m\ue1ximos niveles poblacionales (200,5 individuos) detect\ue1ndose 39,66% de parasitismo. As\ued, Metaphycus sp. durante ese per\uedodo de estudio, result\uf3 un importante factor de regulaci\uf3n de las poblaciones de Capulinia sp

Miniature curved artificial compound eyes.

International audienceIn most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories

Alteration of Forest Structure Modifies the Distribution of Scale Insect, Stigmacoccus garmilleri, in Mexican Tropical Montane Cloud Forests

Stigmacoccus garmilleri Foldi (Hemiptera: Margarodidae) is an ecologically important honeydew-producing scale insect associated with oak trees (Quercus spp.) in highland forests of Veracruz, Mexico. The honeydew exudates of S. garmilleri serve as a significant nutrient source to many species of birds, insects, and sooty molds. Oak trees found in the forest interior, forest edge, and those scattered in pasture areas support scale insect colonies, though the pattern of insect infestations on trees within these varying landscape types has not been elucidated. This study aims to describe the distribution of scale insect infestation and any distinctions in honeydew production based on tree location. Scale insect density, honeydew volume, and sugar concentration were surveyed throughout a continuous landscape that included both patches of forest and scattered pasture trees. In addition, the anal filament through which the honeydew drop is secreted was also measured and was experimentally removed to test and measure regrowth. Scale insect densities on tree trunks were greatest on pasture trees, while intermediate densities were found on trees at the forest edge, and low densities on interior forest trees, suggesting that trees in disturbed areas are more susceptible to scale insect infestation. Trees with small diameters at breast height had significantly higher insect densities than trees with medium to large diameters. Trunk aspect (North, South, East, and West) was not a significant determinant of scale insect density. In forested areas higher densities of scale insects were found at three meters height in comparison to lower heights. Sugar concentrations and drop volumes of honeydew in forest and pasture areas were not significantly different. However, scale-insect anal tubes/filaments were significantly longer in pasture than they were in forests. Sugar concentrations of honeydew appeared to be positively correlated with temperature and negatively correlated with relative humidity. Experiments indicated that anal filaments could grow approximately 4 mm every 24 hours, and average tube growth was significantly faster in pasture than in forest, suggesting that there may be a physiological effect on the insect due to landscape disturbance. The results obtained in this study describe the increases in scale insect infestation of trees with forest disturbance. The effect of these increased scale insect densities on the host tree physiology is still to be resolved