A method for space-variant deblurring with application to adaptive optics imaging in astronomy

Images from adaptive optics systems are generally affected by significant distortions of the point spread function (PSF) across the field of view, depending on the position of natural and artificial guide stars. Image reduction techniques circumventing or mitigating these effects are important tools to take full advantage of the scientific information encoded in AO images. The aim of this paper is to propose a method for the deblurring of the astronomical image, given a set of samples of the space-variant PSF. The method is based on a partitioning of the image domain into regions of isoplanatism and on applying suitable deconvolution methods with boundary effects correction to each region. The effectiveness of the boundary effects correction is proved. Moreover, the criterion for extending the disjoint sections to partially overlapping sections is validated. The method is applied to simulated images of a stellar system characterized by a spatially variable PSF. We obtain good photometric quality, and therefore good science quality, by performing aperture photometry on the deblurred images. The proposed method is implemented in IDL in the Software Package "Patch", which is available on http://www.airyproject.eu.Comment: 11 pages, 9 figures, 7 tables, accepted by A&

Novel functional microRNAs from virus-free and infected Vitis vinifera plants under water stress

MicroRNAs (miRNAs) are small non-coding RNAs that regulate the post-transcriptional control of several pathway intermediates, thus playing pivotal roles in plant growth, development and response to biotic and abiotic stresses. In recent years, the grapevine genome release, small(s)-RNAseq and degradome-RNAseq together has allowed the discovery and characterisation of many miRNA species, thus rendering the discovery of additional miRNAs difficult and uncertain. Taking advantage of the miRNA responsiveness to stresses and the availability of virus-free Vitis vinifera plants and those infected only by a latent virus, we have analysed grapevines subjected to drought in greenhouse conditions. The sRNA-seq and other sequence-specific molecular analyses have allowed us to characterise conserved miRNA expression profiles in association with specific eco-physiological parameters. In addition, we here report 12 novel grapevine-specific miRNA candidates and describe their expression profile. We show that latent viral infection can influence the miRNA profiles of V. vinifera in response to drought. Moreover, study of eco-physiological parameters showed that photosynthetic rate, stomatal conductance and hydraulic resistance to water transport were significantly influenced by drought and viral infection. Although no unequivocal cause–effect explanation could be attributed to each miRNA target, their contribution to the drought response is discussed