1,720,973 research outputs found
Molecular identification of two phytoplasma strains associated with the gladiolus virescence disease in Iran
No full textSevere symptoms of virescence in gladiolus flowers were observed in the Chaharmahal-Bakhtiari province of Iran in 2023. In the areas surveyed the disease incidence ranged from 5% to 40% and has a substantial economic impact, posing a serious threat to gladiolus cut flower production. Given that these disease symptoms have been reported to be associated with the presence of phytoplasmas, verifying the presence and identity of these bacteria is essential for a focused disease management. Sequence analyses of the 16S rRNA, ribosomal protein (rp), and tuf genes confirmed the presence of 'Candidatus Phytoplasma asteris' and 'Ca. P. tritici' strains in the symptomatic plants. Restriction fragment length polymorphism indicated that the phytoplasmas in the 30 symptomatic gladiolus plant samples examined belong to subgroups 16SrI-F and 16SrI-R. These results were also confirmed through phylogenetic analysis on the three studied genes in which the two strains resulted closely related to phytoplasmas in the 16SrI-R and 16SrI-F subgroups, respectively. This is the first report of 16SrI-R and 16SrI-F phytoplasmas associated with the virescence disease in gladiolus plants
Explainable artificial intelligence for crypto asset allocation
No full textMany investors have been attracted by Crypto assets in the last few years. However, despite the possibility of gaining high returns, investors bear high risks in crypto markets. To help investors and make the markets more reliable, Robot advisory services are rapidly expanding in the field of crypto asset allocation. Robot advisors not only reduce costs but also improve the quality of the service by involving investors and make the market more transparent. However, the reason behind the given solutions is not clear and users face a black-box model that is complex. The aim of this paper is to improve trustworthiness of robot advisors, to facilitate their adoption. For this purpose, we apply Shapley values to the predictions generated by a machine learning model based on the results of a dynamic Markowitz portfolio optimization model and provide explanations for what is behind the selected portfolio weights
Mixed phytoplasma infection in Cressa cretica showing witches’ broom symptoms in Iran
No full textA Cressa cretica witches’ broom disease was observed in Ardakan (Yazd province, Iran) during 2018-2021. Total DNAs extracted
from eighteen symptomatic and four asymptomatic plants were subjected to nested PCR assays using primers amplifying the
phytoplasma 16S ribosomal DNA. Expected length of PCR amplification products was detected in all symptomatic plant
samples but not in those asymptomatic. RFLP analysis of the R16F2n/R16R2 amplicons showed mixed infection of
phytoplasmas enclosed in 16SrXXIX and 16SrI groups
Threat of tamarisk phytoplasmas in man-made tamarisk forest for agricultural crops and natural resources plants in Iran
No full textOver the past two decades, symptoms of tamarisk witches’ broom, yellowing, and little leaf were observed with extensive distribution up to 100% in some areas in man-made tamarisk forest in rural deserts of central regions of Iran in Chah Afzal (Yazd province). Using direct and nested polymerase chain reaction on the phytoplasma ribosomal and non-ribosomal genes followed by RFLP and phylogenetic analyses revealed the presence of ‘Candidatus Phytoplasma asteris’ (16SrI-B subgroup), ‘Ca. P. australasiae=australasiaticum’ (16SrII-D subgroup), and ‘Ca. P. trifolii’ (16SrVI-A subgroup). Based on the results, tamarisk represent a relevant source of infection for the agricultural crops and natural resources plants. Since phytoplasma strains detected on the tamarisk trees are similar to important phytoplasma diseases on different plant species in this area, it is possible that tamarisk trees have an important role in the epidemiology of phytoplasma disease and cause great damages. Threat of tamarisk witches’ broom phytoplasma diseases in man-made tamarisk forest for agricultural crops and natural resources plants is serious and management of the disease at the earliest opportunity is recommended
Identification and impact of phytoplasmas associated with greenhouse cucumber phyllody in Iran
Get PDFCucumber phyllody symptoms were observed in greenhouse cucumber plants during 20142018 in all surveyed areas of central and west of Iran where the highest disease incidence was up to 82% in Taft (Yazd province). Symptoms exhibited by diseased plants were virescence, phyllody and sterility of the flowers. For verification of phytoplasma presence and identity, total DNAs were extracted from 44 symptomatic and six asymptomatic plants that were subjected to PCR amplifying 16S rRNA genes of phytoplasmas. PCR ampli-cons of the expected size were obtained only from the symptomatic plants. RFLP analysis of R16F2n/R2 amplicons showed patterns identical to those of the clover proliferation (16SrVI) and “stolbur” (16SrXII) phytoplasma groups. Consensus sequences corresponding to phytoplasma strains from the two local-ities Taft and Shahrekord showed 99% identity with phytoplasmas enclosed in groups 16SrVI and 16SrXII, respectively. Phylogenetic analysis confirmed that these phytoplasmas cluster with ‘Candidatus Phytoplasma trifolii’ and ‘Ca. P. solani’, respectively. Virtual RFLP provided profiles identical to the patterns of 16SrXIIA and 16SrVIA phytoplasma subgroups. These phytoplasma subgroups were previously reported in different plant species growing near to the greenhouse cucumber areas in Iran, and play a possible role in the epidemiology of disease for its dissemination
Occurrence and molecular characterization of a 16SrI-R subgroup phytoplasma associated with Aquilegia vulgaris phyllody disease
Get PDFDuring 2016–2017 surveys, carried out for phytoplasma diseases in ornamental plants in Chaharmahal and Bakhtiari provinces, Iran, found symptoms of virescence, phyllody, reduced size of leaves and flowers in columbine (Aquilegia vulgaris). Total DNAs extracted from symptomatic and symptomless plants were tested for the presence of phytoplasma using P1/P7 and R16F2n/R16R2 primers in direct and nested PCR producing amplicons of about 1.8 and 1.2 kb, respectively, from all symptomatic A. vulgaris plants, but not from symptomless ones. The consensus sequence of the detected phytoplasma named Aquilegia phyllody (APh) was 100% identical with strains clustering to phytoplasmas enclosed in the 16SrI group as also confirmed by phylogenetic analyses. Both real and virtual restriction fragment length polymorphism analysis of R16F2n/R16R2 amplicons showed profiles that were identical to each other and indicated the affiliation of the APh phytoplasma to the 16SrI-R subgroup. This is the first report of a 16SrI-R phytoplasma associated with this A. vulgaris phyllody disease
Occurrence and identification of a phytoplasma associated with Pinus brutia witches’ broom disease in Isfahan, Iran
No full textBetween 2016 and 2017, symptoms of witches’ broom, proliferation, drying of twigs and ball-like structures formation were observed in Pinus brutia in urban green areas and parks in Isfahan (Iran). All samples from affected P. brutia trees resulted positive in nested-PCR using primer pairs targeting the phytoplasma 16S rRNA gene. Amplicons were obtained only from all the symptomatic pine tree samples and RFLP analyses of R16F2n/R16R2 amplicons with KpnI, AluI, HaeIII, HhaI, HpaII, MseI, RsaI,ThaI, BfaI and TaqI restriction enzymes showed the presence of phytoplasmas enclosed in the 16SrVI group. Four amplicons were sequenced and showed 100% identity to each other. One of these sequences was deposited in the GenBank database (accession number MK158098) and the virtual RFLP pattern was identical (similarity coefficient 1.00) to the reference pattern of 16Sr group VI, subgroup A confirming that the phytoplasma detected in pine is a member of 16SrVI-A subgroup. This is the first report of a 16SrVI-A phytoplasma strain associated with pine tree witches’ broom (P. brutia) disease
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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