1,720,994 research outputs found
Società Toscana di Scienze Naturali residente in Pisa. Cenni storici e catalogo dei periodici della biblioteca
No full textProtective effect of soil microbial respose due to organic substance addition in radical phytopaties
No full textBacteria associated to arbutoid mycorrhizae in Arbutus unedo L
No full textInvestigations on ultrastructural aspects of arbutoid mycorrhizae in Arbutus unedo showed the occurrence of bacteria between the hyphae of the mantle. Sequential cuts of mycorrhizal tissue revealed the spatial distribution of bacteria: in the outer region of the hyphal mantle many bacteria were present in the microniches formed by the hyphae interwoven around the roots; in the inner region bacteria formed microaggregates enclosed between hyphae, immersed in an electron-dense matrix. Quantitative and qualitative determinations showed the consistent occurrence of Azospirillum-like bacteria in the mycorrhizosphere and endosphere, whichever inoculum was utilized for the syntheses of arbutoid mycorrhizae. The hypothesis of a strict association between arbutoid mycorrhizae and Azospirillum-like bacteria is discussed
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
ANTAGONISTIC EFFECTS OF SOIL BACTERIA ON FUSARIUM-OXYSPORUM SCHLECHT F-SP DIANTHI (PRILL AND DEL) SNYD AND HANS .3. RELATION BETWEEN PROTECTION AGAINST FUSARIUM-WILT IN CARNATION AND BACTERIAL ANTAGONISTS COLONIZATION ON ROOTS
No full textFusarium oxysporum f. sp. dianthi, pathogenic on carnation plants is very sensitive to Bacillus subtilis M51 inhibition. Fusarium oxysporum disease (fusariosis) is prevented for a period of two months after treatment of plants with Bacillus subtilis M51. The persistence of B. subtilis M51, marked for selenomycin resistance (MZ51) and inoculated on the roots of carnation cuttings was studied. Soil used was two types: naturally infested with Fusarium oxysporum and free from this pathogen. Bacterial cells presence on the roots was detected by direct plating and the presence of the pathogen in the roots was investigated by histological assays. Evidence gathered by these procedures suggest that plant protection is dependent on the physical presence of B. subtilis M51 cells on the root
Early and Middle Ordovician events of Baltoscandia
No full textThe Baltoscandia region was a wide platform covered by an epicontinetal sea on the Baltic Craton during Early to Middle Ordovician. In the same period the Baltica palaeoplate moved rapidly from high southern latitudes towards low southern latitudes. This northern directed movement crossed climate zones and the platform sedimentary succession changes from predominantly siliciclastic sedimentary rocks with minor carbonate in the late Cambrian to Early Ordovician to increasingly carbonate-rich rocks: first by cool, temperate shallow-water limestone (Orthoceras Limestone) and then by warmer temperate shallow-water carbonate and marl accumulation at the end of the Middle Ordovician (Darriwilian).
True conodont faunal endemism within Baltica has not been observed. Instead Early and Middle Ordovician multielement conodonts from Baltoscandia record a series of faunal events comprising (1) conodont faunal phylogenetic developments, (2) migration events, (3) immigration events and (4) significant faunal turnovers.
The late Cambrian and earliest Ordovician (early Tremadocian) record of the conodont faunas is incomplete for the Baltic Platform, because of pronounced global sea-level lowstand. The conodont phylogenic evolution starting from late Tremadocian (Early Ordovician) comprises the significant lineage of Paltodus, ‘Acodus’ (= Acodus deltatus sensu stricto), Trapezognathus and to Lenodus and from the top Floian the lineages of Baltoniodus and Microzoarkodina. Several migration events include genera in the Tremadocian and the significant Oepikodus evae acme in the Floian. The dispersal of the bi-membrate genus Eoplacognathus (sensu stricto) in the Darriwilian was a significant migration event from deeper-water setting at the margin of the craton and onto the platform. Visitors (i.e. Yangtzeplacognathus) immigrating from other palaeocontinents also reached the Baltica plate. These stayed only for a short period and disappeared equally fast as they appeared. However, the precise geographic source region for invaders and the palaeoceanographic conditions that facilitated dispersal into the Baltoscandia platform is still poorly understood. Biogeographic analysis indicates that in the Early Ordovician communication exclusively with Laurentia prevailed. This line of communication was disturbed at the beginning of the Middle Ordovician (Dapingian), where communication with Peri-Gondwana faunas also appeared on the Baltic platform. The Dariwillian invasions were multidirectional that involved taxa immigrating into the Baltoscandian region from both Laurentia and peri-Gondwana plates that approached continental margins of the Baltica palaeocontinent. The late Darriwilian–early Sandbian conodont faunas of Baltica show close similarities to faunas in the oceans, at margins of Laurentia, South China, and other adjacent tectonic plates and terranes, which indicate their semi-cosmopolitan distribution.
The synchronicity of the geologic, climatic and oceanographic events supports the influence of geologic events on conodont evolution on Baltica. Causal links between the faunal turnovers includes predominantly (1) sea-level changes (2) tectonics and (3) global climate change. The trends also correlate with the perturbations in the carbon cycle, with the d13C minima corresponding to the low diverse fauna and faunal turnover and the positive values generally occurring during radiations
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