1,721,004 research outputs found
The contribution of the soil biophysical properties to the management of temperate agrosystems
No full textTHE CONTRIBUTION OF THE SOIL BIOPHYSICAL PROPERTIES TO THE MANAGEMENT OF TEMPERATE AGROSYSTEMS
Several studies point to the influence of soil aggregation on microbial communities and their activities. The soil aggregates, or more in detail their pores are habitats where microorganisms live and biogeochemical processes occur.
The most widely used traditional approaches for the aggregates separation are based on the wet sieving or on density fractionation. On the obtained aggregate fractions it is then possible to determine the microbial biomass functionality. In contrast with the standard methods, in this project we will study fractions of macro and microaggregates separated on the base of the different breakdown mechanisms induced by water.
The goal is to identify and to test biophysical, innovative and effective indexes for the assessment of the maintenance or improvement of soil quality induced by different management procedures, in forest and agricultural ecosystems.
More in detail, for the forest ecosystem the study concerns an oak wood and an alfalfa grassland located in the Apennine mountain belt, while for the agricultural ecosystem agrarian sites differently managed for their fertility will be considered in Bologna plain.
For both ecosystems the main pools of organic matter and microbial activity will be investigated both in soils and in aggregate fractions. The microbial activity evaluation concern the quantification of extracellular enzyme activity using fluorimetric assays in microplate scale.
The obtained data will be related to the data of the aggregates stability and soil porosity in order to identify the representative parameters of soil quality and, therefore, the useful indicators for the assessment of the soil quality changes caused by the different management
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
Genotoxicity induced by amorphous silica powders in murine alveolar macrophages (RAW 264.7) and human epitelial lung cells (A549). Effect of dimension and superphicial morphology
No full textDoes the crystal habit modulate the genotoxic potential of silica particles? A cytogenetic evaluation in human and murine cell lines
No full textCrystalline silica inhaled from occupational sources has been classified by IARC as carcinogenic to humans;in contrast, for amorphous silica, epidemiological and experimental evidence remains insufficient. Thegenotoxicity of crystalline silica is still debated because of the inconsistency of experimental results(“variability of silica hazard”), often related to the features of the particle surfaces. We have assessedthe role of crystal habit in the genotoxicity of silica powders. Pure quartz (crystalline) and vitreous silica(amorphous), sharing the same surface features, were used in an in vitro study with human pulmonaryepithelial (A549) and murine macrophage (RAW264.7) cell lines, representative of occupational andenvironmental exposures. Genotoxicity was evaluated by the comet and micronucleus assays, and cyto-toxicity by the trypan blue method. Cells were treated with silica powders for 4 and 24 h. Quartz but notvitreous silica caused cell death and DNA damage in RAW264.7 cells. A549 cells were relatively resistantto both powders. Our results support the view that crystal habit per se plays a pivotal role in modulatingthe biological responses to silica particles
Utilizzo di bivalvi d'acqua dolce (Unio pictorum) come bioindicatori degli ambienti fluviali. Esperimenti di trapianto nel fiume Cecina
No full textAttività antropiche sia attuali che pregresse concorrono, insieme a manifestazioni d’origine naturale, alla contaminazione ambientale del fiume Cecina (Toscana centro-meridionale). Analisi chimico-fisiche hanno indicato una contaminazione dei sedimenti e del biota da parte di metalli pesanti tra i quali il mercurio. Oggetto del presente studio è il monitoraggio ambientale attraverso biomarker di genotossicità e funzionalità lisosomale in tre località del suddetto fiume, una delle quali, di controllo, posta in un’area protetta. Bivalvi d’acqua dolce, provenienti dal Lago Maggiore, sono stati posti in gabbie, contenenti ognuna 15 organismi, e trapiantati per 30 giorni nei siti di studio. Gli effetti genotossici sono stati analizzati su cellule branchiali mediante il Test della Cometa ed il Test del Micronucleo per stimare, rispettivamente, le rotture della doppia elica del DNA e la presenza di cellule micronucleate. Il Test del Rosso Neutro, condotto sull’emolinfa, è stato effettuato per valutare la stabilità lisosomale. Le risposte fornite da quest’ultimo biomarker hanno differenziato significativamente (p<0.01) il livello di contaminazione ambientale nei tre siti. I risultati dei test di genotossicità non hanno discriminato le tre stazioni. L’alta percentuale di cellule apoptotiche osservata nei preparati di tutti gli individui potrebbe aver interferito con l’interpretazione dei dati di genotossicità. © 2007 AIOL-SItE. All rights reserve
Cellular biomarkers in the freshwater bivalve Unio pictorum. A case- study from a contamined italian river
No full textGenotoxicity Evaluation of the Soybean Isoflavone Genistein in Human Papillary Thyroid Cancer Cells. Study of Its Potential Use in Thyroid Cancer Therapy
No full textGenistein is one of the several known isoflavonic phytoestrogens found in a number of plants, with soybeans and soy products being the primary food source. The aim of the study is to evaluate if genistein is able to exert antineoplastic action in primary human papillary thyroid cancer (PTC) cells. Thyroid tissues were treated with genistein (1-10-50-100 μM). Cell viability, proliferation, DNA primary damage and chromosomal damage were evaluated. An antiproliferative effect was induced by the highest doses of genistein, and such an effect was synergistically enhanced by the cotreatment with the antineoplastic drug sorafenib. Comet assay did not show any genotoxic effect in terms of primary DNA damage at all the times (4 and 24 h) and tested doses. A reduction of hydrogen peroxide-induced DNA primary damage in primary thyrocytes from PTC cells pretreated with genistein was observed. Data suggest that genistein exerts antineoplastic action, does not induce genotoxic effects while reduces oxidative-induced DNA damage in primary thyrocytes from PTC cells, supporting its possible use in therapeutic intervention
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