1,720,970 research outputs found
Design Considerations for Massively Parallel Channel Estimation Algorithms
No full textAccurate channel estimation may require complex algorithms for effective results, especially in the case of a multiuser detector. The introduction of Graphic Processing Units (GPUs) has opened up new possibilities for the implementation of numerically intensive channel estimation algorithms. This paper studies the implementation on GPUs of channel estimation algorithms for channels affected by strong phase noise. While classic Maximum Likelihood estimation is still the most competitive in terms of throughput and memory bandwidth, Steepest Ascent algorithms show the largest speed improvement due to their structure, which is the most suitable for implementation on a parallel processor like the GPU
Morphological and Molecular Identification of Dactylonectria macrodidyma as Causal Agent of a Severe Prunus lusitanica Dieback in Italy
No full textDuring the summer of 2016, severe dieback was observed on young potted Prunus lusitanica (Portugal laurel) plants in a nursery in the Pistoia province (Tuscany, Italy). Cylindrocarpon-like isolates were consistently recovered from diseased plant tissues. The combination of morphological and molecular traits, including sequence data of histone 3 and β-tubulin genes (HIS3, TUB2) and internal transcribed spacers (ITS), allowed the identification of Dactylonectria macrodidyma (Halleen, Schroers & Crous) L. Lombard & Crous (asexual form Cylindrocarpon macrodidymum) as the causal agent of the disease. Pathogenicity tests reproduced disease symptoms observed in the nursery after six months fulfilling Koch’s postulates. D. macrodidyma is a soilborne plant pathogen and is to be considered of great economic importance on P. lusitanica, especially under favorable conditions such as stress and/or reduction of plant vitality. The increasingly frequent reports of the disease caused by the pathogen in various nurseries suggest that pot cultivation, together with prolonged drought periods, may play a role in favoring infections. To the best of our knowledge, this is the first report worldwide of the occurrence of dieback on Prunus lusitanica caused by D. macrodidyma
Molecular detection of the seed-borne pathogen colletotrichum lupini targeting the hyper-variable igs region of the ribosomal cluster
Full text linkLupins anthracnose is a destructive seed and airborne disease caused by Colletotrichum lupini, affecting stems and pods. Primary seed infections as low as 0.01–0.1% can cause very severe yield losses. One of the most effective management strategies is the development of a robust and sensitive seed detection assay to screen seed lots before planting. PCR-based detection systems exhibit higher levels of sensitivity than conventional techniques, but when applied to seed tests they require the extraction of PCR-quality DNA from target organisms in backgrounds of saprophytic organisms and inhibitory seed-derived compounds. To overcome these limitations, a new detection protocol for C. lupini based on a biological enrichment step followed by a PCR assay was developed. Several enrichment protocols were compared with Yeast Malt Broth amended with ampicillin, streptomycin, and lactic acid were the most efficient. A species-specific C. lupini primer pair was developed based on rDNA IGS sequences. The specificity was evaluated against 17 strains of C. lupini, 23 different Colletotrichum species, and 21 different organisms isolated from seeds of Lupinus albus cv. Multitalia, L. luteus cv. Mister, and L. angustifolius cv. Tango. The protocol described here enabled the detection of C. lupini in samples artificially infected with less than 1/10,000 infected seed
First report of Colletotrichum godetiae causing grape (Vitis vinifera) berry rot in Italy
No full textIn October 2016, rotting grape berries were detected on grapevine (Vitis vinifera) in Livorno (Nugola, Tuscany, Italy). Symptoms on grape berry skins varied from circular brown spots to rotting fruits. Both berries and petioles were covered with creamy salmon-colored masses of conidia. Rotten grape berries lost turgor and turned into ‘mummies’ over time. Symptoms suggested that a member of the genus Colletotrichum could be involved. Single spore cultures were obtained from conidial masses and grown in the laboratory at 25°C with a 12-h light period on potato dextrose agar (PDA). Monoconidial isolates had light gray cottony aerial mycelium with colony color ranging from whitish to dark gray, while the reverse ranged from whitish to salmon-pink. Conidia were hyaline and unicellular, cylindrical or clavate, and often with a light median constriction. However, Colletotrichum spp. are often difficult to distinguish morphologically. Total genomic DNA was extracted from monoconidial isolate SS354. The ITS region of rDNA and partial GAPDH, CHS-1, HIS3, ACT, and TUB2 genes were amplified and sequenced according to Damm et al. (2012). Sequences were deposited in GenBank (accession no. KY293406 for ITS, KY293407 for TUB, KY293403 for CHS, KY293405 for HIS3, KY293402 for ACT, and KY293404 for GAPDH). The multilocus phylogenetic analysis carried out with the obtained and reference sequences (Damm et al. 2012) revealed that the SS354 isolate clustered within C. godetiae. Pathogenicity tests were performed in laboratory by inoculating detached grape berries with or without petioles at the petiole insertion point with 20 μl of a conidial suspension (105 conidia/ml) of the isolate SS354. Grape berries without petiole developed symptoms similar to those observed in the field. Fungal colonies reisolated from the lesions on berries were morphologically identical to isolate SS354. Control grape berries inoculated with sterile water remained healthy as well as grape berries with petioles inoculated with the pathogen. This suggests that C. godetiae is able to infect wounded grape berries. However, information regarding other infection routes were not searched, as this was not the aim of this work. This is the first report of C. godetiae causing grape berry rot in Italy. The phylogenetic analysis reveals that C. godetiae SS354 is closely related to C. godetiae RB118, the causal agent of anthracnose on grapevine in the U.K. (Baroncelli et al. 2014). Since C. godetiae is polyphagous, cross-infections between grape and other crops are possible. Remarkably, Cacciola et al. (2012) reported C. clavatum (syn. C. godetiae) as the prevalent Colletotrichum species associated with epidemic outbreaks of olive anthracnose in Italy. However, at present, no information regarding cross-infection of C. godetiae between grapevine and olive are available. Due to the high economic and social value of wine production in Italy (in 2013 only in Tuscany the production of grapes accounted for 8 million tons), a monitoring plan based on simple molecular identification tools should be advisable
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Genome sequence of Fusarium graminearum ITEM 124 (ATCC 56091), a mycotoxigenic plant pathogen
No full textFusarium graminearum is among the main causal agents of Fusarium head blight (FHB), or scab, of wheat and other cereals, caused by a complex of Fusarium species, worldwide. Besides causing economic losses in terms of crop yield and quality, F. graminearum poses a severe threat to animal and human health. Here, we present the first draft whole-genome sequence of the mycotoxigenic Fusarium graminearum strain ITEM 124, also providing useful information for comparative genomics studies
First report of Verticillium dahliae causing verticillium wilt on Stevia rebaudiana in Europe
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