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. pp. 78. Cazzanti, L. and R.M. Gupta. 2007. Local similarity discriminant analysis. Proceedings of the 24th International Conference on Machine Learning, ICML. Corvallis, Oregon. pp. 137

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Community Ecology
Authors: G. Bacaro, D. Rocchini, C. Duprè, M. Diekmann, F. Carnesecchi, V. Gori, and A. Chiarucci

. 2007 8 41 46 Bacaro, G., C. Ricotta and S. Mazzoleni. 2007. Measuring beta-diversity from taxonomic similarity. J. Veg

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processes: the role of similarity in GIS applications for landscape analysis . In: M. Fisher , H. Scholten and D. Unwin (eds), Spatial Analytical Perspectives on GIS. Taylor and Francis , London . pp. 175 – 185

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The aim of this paper was to find possible link between molecular and morphological similarities of 38 Hungarian white grape varieties. Three aspects of morphological and molecular similarity were assessed in the study: comparison of the ordered variety pairs, assessment of molecular and morphological mean similarity differences and separation of varieties into similar groups by divisive cluster analysis to define (DIANA). Molecular similarity was calculated from binary data based on allele sizes obtained in DNA analysis. DNA fingerprints were determined at 9 SSR loci recommended by the European GrapeGen06 project. Morphological similarity was calculated on the basis of quantitative morphological descriptors. Morphological and molecular similarity values were ordered and categorized after pairwise comparison. Overall correlation was found to be weak but case by case assessment of the variety pairs confirmed some coincidence of molecular and morphological similarity. General similarity position of each variety was characterized by Mean Similarity Index (MSI). It was calculated as the mean of n-1 pair similarity values of the variety concerned. Varieties were ordered and compared by the difference of the index. Five varieties had low morphological and high molecular MSI meaning that they share several SSR marker alleles with the others but seems relatively distinct according to the expression of their morphological traits. Divisive cluster analysis was carried out to find similar groups. Eight and twelve cluster solutions proved to be sufficient to distinct varieties. Morphological and molecular similarity groups partly coincided according to the results. Several clusters reflected parent offspring relations but molecular clustering gave more realistic results concerning pedigree.

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Similarity between seed bank and aboveground vegetation is frequently studied in order to better understand how community composition is affected by factors such as disturbance and succession. Grassland plant communities are known to be sensitive to shifts in precipitation and increases in temperature associated with climate change, but we do not know if and how these factors interact to affect the similarity between seed bank and aboveground vegetation. Also unknown is how the impact of grazing, the dominant land-use in grasslands, will interact with climatic conditions to affect similarity. We manipulated precipitation and temperature, and cut vegetation (as a proxy for grazing) at a grassland site for three years. Percent cover of aboveground vegetation was estimated in the third year, and compared with persistent seed bank samples taken in the year prior from the same plots. Similarity increased with reduced precipitation, was unresponsive to warming, and decreased with clipping. The aboveground community responded strongly to the treatments, while the seed bank community did less so, suggesting similarity responses were largely driven by changes in aboveground vegetation. Because of the importance of the seed bank in vegetation regeneration, understanding the relationship between seed bank and aboveground vegetation will improve our understanding of plant community dynamics under climate change and varied management (grazing) intensities.

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Similarity indices are often used for measuring b-diversity and as the starting point of multivariate analysis. In this study, I used simulation to examine the direction and amount of bias in estimates of two similarity indices, Jaccard Coefficient (J) and incidence-based J (J^). I design a novel simulation to generate three sets of assemblages that vary in species richness, species-occurrence distributions, and b-diversity. I characterized assemblage differences with the ratio of [proportion of rare species in all shared species / proportion of rare species in all unshared species] (i.e., PR ss/PR us) and the Pearson’s correlation in the probabilities of shared species between two assemblages (i.e., share-species correlation). I found that J was subject to strong positive or negative bias, depending on PR ss/PR us. J^ was mainly subject to negative bias, which varied with share-species correlation. In both indices, bias varied substantially from one pair of assemblages to another and among datasets. The high variation in the bias across different comparisons of assemblages may compromise b-diversity estimation established at low sampling efforts based on the two indices or their variants.

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Similarities and differences in the immune systems of plants and animals are discussed in relation to non-specific and specific immunity (resistance), systemic acquired resistance (immune memory), transgenerational immune memory and gene silencing. Furthermore, we attempt to answer the question “what is inhibiting or killing pathogens during the immune (resistance) process”? Therefore, the possible roles of reactive oxygen species and antioxidants in pathogen inhibition are evaluated in different types of plant disease resistance.

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We have examined the community structure indices (species richness, dominance, diversity and similarity) of the rove beetles (Staphylinidae) assemblages in three differently treated apple orchards in Hungary.During the survey, a total number of 728 specimens belonging to 73 species were collected with pitfall traps. The dominant species were Omalium caesum, Drusilla canaliculata, Dexiogyia corticina, Mocyta orbata and Styloxys insecatus .Out of the differently treated orchards, the staphylinid abundance was the higher in the abandoned than in the conventionally treated and in integrated pest management orchards.The diversity profile of the communities showed that there were no differences between the diversity of the conventionally treated and abandoned orchards, and both were significantly more diverse than the IPM orchard. The similarity indices indicated that the forming dominance of the species was also influenced by the treatment. The distribution of the dominant species in each pitfall trap used in each plot shows the insecticide tolerance of the species

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Community structure (species richness, dominance, similarity, diversity and seasonal dynamics) of the rove beetles (Staphylinidae) was examined in an abandoned, a conventional and an organic vineyard management plot of an experimental vineyard in Hungary.During the survey, a total number of 493 specimens belonging to 33 species were collected by pitfall traps. The dominant species were Sphenoma togata, Xantholinus linearis and Pseudocypus penetrans that presented 76.66% of all staphylinids collected in the vineyard. All of the most common staphylinid species had only one generation per year and overwintered as adults.There were significant differences in species richness and abundance; both were the highest in the abandoned plot. The dissimilarity in species composition between the differently treated plots was also high. The diversity was the highest in organic, and the lowest in conventionally treated plot, while the abandoned one showed an intermediate value.

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Abstract

After a brief summary on the properties of the Epstein-Barr virus (EBV), the course and latency stages of the infection, the characteristics of infectious mononucleosis (IM), and other disorders caused by this virus, as well as the course of the serological responses to EBV, the current paper focuses on the role of EBV in two autoimmune disorders: multiple sclerosis (MS), and systemic lupus erythematosus (SLE). Diverse evidence suggests that infection by EBV during late childhood or young adulthood may have a role in the pathogenesis of MS. These include the similarity between the geographical distribution of IM and MS, the high risk of contracting MS by individuals who have recovered from IM, the elevation of the titers of IgG antibodies against EBV nuclear antigens occurring years before the initial manifestations of MS, and the extremely rare occurrence of MS in individuals seronegative for EBV. However, the data on the mechanism underlying the relationship between EBV and MS are controversial. Moreover, many observations indicate that EBV contributes also to the pathomechanism of SLE. However, this contribution differs from the relationship between EBV and MS, as shown by the lack of any increase in the risk of SLE after IM. In SLE, EBV serology is quantitatively and qualitatively different from the normal response — that is, EBV viral load is higher and a strong cross-reaction can be detected between certain EBV antigens and autoantigens of pathological importance. These observations, along with the findings pointing to a possible role of EBV in rheumatoid arthritis and myasthenia gravis indicate that infection by EBV may be one of the environmental factors, which can facilitate the development of some autoimmune disorders in genetically susceptible individuals.

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