1,721,193 research outputs found
Mycoremediation for degrading hydrocarbon pollutants
No full textNowadays waste products derived from human life and industrial activities represent a serious problem in the world, due to their difficulty of disposal and recovery. Although in the past little importance has been given to environmental quality, the last two decades have been characterized by an increasing awareness on the topic; nevertheless, pollution from many organic substances such as hydrocarbons, remains a mostly unsolved issue, because these compounds are often recalcitrant and show high levels of toxicity.
In recent years, the scientific interest for hydrocarbons is mainly related to their recognized carcinogenic action resulting from the metabolic transformations of these compounds into diol-epoxides, molecules able to bind to DNA and to induce genetic mutations (Man et al.2013).
These recalcitrant substances are known to enter the environment frequently and in large scale via several routes (Singh, 2006). One of the major routes is the spill on the ground, often due to neglected maintenance of structures dedicated to production, storage and distribution; as concerns terrestrial environments, these phenomena may determine some harmful effects such as surface water pollution through runoff, groundwater pollution by leachate, evaporative atmospheric pollution, sublimation or wind drift, thus resulting in decreases in crop yields, poisoning through the food chain and impact on the landscape. Another route includes production, storage and transportation which represent a hazard due to accidental releases of petroleum compounds, mostly in marine environments, especially involving bottom sediments.
Currently, restoring areas polluted by hydrocarbon products usually requires some chemical, physical, and biological treatments. Among these, biological treatments are more suitable for sustainable and economic applications because traditional remediation techniques for the treatment of hydrocarbon compounds are often limited by application costs and low efficiency.
Hence, the present study proposes a sustainable and economic biotechnology aimed at allowing the recovery and disposal of soils and marine sediments contaminated by hydrocarbons. The project represents a response to the need for providing a biotechnological protocol devoted to safeguard the environment andterritory and to allow the reclamation of sites contaminated by substances which have been deemed harmful to human health. As it is known, some fungal species are extremophiles, able to adapt to adverse environmental conditions (both for abiotic factors and for nutrient deficiency) which would be limiting for most living organisms (Gadd, 2007); this feature makes some fungi an important tool to biodegrade pollutant compounds
(Kumar et al. 2011). For these reasons, as concerns the hydrocarbon pollution of soils and marine sediments, the present study proposes an alternative solution to the traditional technologies of rehabilitation and environmental remediation, through the study, isolation, identification, and exploitation of those fungi able to degrade these toxic compounds. Several experiments reported in the literature demonstrate that fungi have an ability to metabolize and degrade many hydrocarbon compounds, such as oils, petroleum derivatives, and polycyclic aromatic hydrocarbons (Cerniglia et al. 2010; Harms et al. 2011; Al-Jawhari et al. 2014; Reyes-César et al. 2014; Marco-Urrea et al. 2015).
The studies conducted so far provide a general overview about fungal remediation activity, contributing to support the hypothesis of the possible large-scale application of some fungi in the degradation processes of organic pollutants. The research is aimed at assessing the sustainability of these innovative biotechnologies and at deepening the knowledge of the factors that may affect the activity of some fungal species or strains within different matrices contaminated by different types of hydrocarbons. The study is the result of a multidisciplinary approach involving mycologists, geologists, chemists, and oceanographers.
The thesis is organized as follows. Chapter 1 presents the hydrocarbons focusing on polycyclic aromatic hydrocarbons (PAHs); it describes the traditional remediation techniques which are currently used and defines the role of fungi in the degradation of recalcitrant organic compounds and in the remediation of contaminated soils and waters (mycoremediation). Chapter 2 details the aims of the thesis, while in Chapter 3 the materials and methods are listed and described.
Chapter 4 deals with the mycological characterization of a marine area polluted by hydrocarbon compounds in relation to different substrates (biotic and abiotic), depths and marine currents, to identify and select a pool of fungal species adaptable to extreme polluted environments, which could be used for bioremediation purposes.
Chapter 5 shows the results of the investigations on 15 fungal species isolated from a real oily slime and screened to assess their ability to degrade a PAH mixture. The most suitable fungal strains were employed in the in vitro degradation tests.
Chapter 6 investigates, through pilot-scale experiments, the role that fungi can play as tools for the remediation of real polluted matrices contaminated by petroleum derivatives.
Finally, Chapter 7 outlines the conclusions, showing the significant importance of the fungal exploitation for recovering marine and terrestrial areas contaminated by hydrocarbons. Furthermore, some hints for future works and applications are provided
El mito entre verdad y mentira en la República de Platón
No full textEl artículo se propone analizar la elaboración del concepto de "verdad" en los primeros tres libros de la "República" de Platón. A través de una lectura de los principales pasajes donde se trata el tema, se subraya la intersección entre verdad y justicia en la cultura ateniense del siglo V y IV, representadas en "República" I-III por los interlocutores de Sócrates, y la vuelta teórica propuesta por este último. La distinción entre verdad de palabra y verdad del alma constituye un presupuesto fundamental en vista de la elaboración de la "noble mentira" y en general para superar los límites de una definición exclusivamente fáctica de la verdad. Sin embargo, la mentira de palabra, que constituye para el filósofo un φάρμακον χρήσιμον contra la locura y la ausencia de conocimiento de los otros, abre al problema de la fascinación oratoria y del riesgo que el filósofo, encantado, se pierda en el entramado de su mismo μύθος.Fil: Greco, Giuseppe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades. Centro de Investigaciones María Saleme Burnichón; Argentin
Invecchiamento della popolazione e spesa farmaceutica a livello regionale
No full textSi evidenzia l'importanza e il peso che la spesa farmaceutica italiana ha sul PIL sottolineando la diversità fra varie regioni, più o meno virtuose, tramite una metodologia statistica volta a cogliere le peculiarità differenziali territoriali
À rebours: Memoria, usi del passato ed emancipazione politica
No full textIl presente contributo si propone di esaminare alcuni aspetti del rapporto che lega uso memoriale del passato ed emancipazione politica, nella prospettiva ambivalente dell’esercizio di un dominio o di un processo di liberazione. In una prima sezione si mette in evidenza il valore di emancipazione che nella Cité divisée Nicole Loraux attribuisce alla pratica storica, opponendola alla memoria pubblica della Francia della fine del XX secolo. In una seconda sezione vengono presi in considerazione alcuni passaggi de Il principe e dei Discorsi di Machiavelli, dai quali si evince una concezione ambivalente della memoria, sempre inserita all’interno di un quadro storicamente situato di conflitti e di lotta per l’egemonia. Il lavoro infine prende in considerazione alcune variazioni intervenute nel ricorso alla memoria della dittatura e del fenomeno dei desaparecidos nei discorsi di Hebe Bonafini, portavoce delle Madres de Plaza de Mayo, per individuarvi il riconfigurarsi di un rapporto con il passato all’interno di pratiche sempre nuove di emancipazione politica.The article analyzes some aspects of the relationship between memorial use of the past and political practice, considered in the double perspective of domination and emancipation. In the first section we address the value Nicole Loraux’s La cité divisée attributes to the practice of history as an emancipatory tool in opposition to the public memory in the late XXth century France. The second section considers some passages of Machiavelli’s Il Principe and Discorsi, in which emerges an ambivalent concept of memory, always placed in historical set of conflicts and fight for hegemony. Finally, the paper considers the public speeches of Hebe Bonafini (leader of Madres de la Plaza de Mayo) and their varying memory of the crimes of the dictatorship period and of the phenomenon of desaparecidos. The ultimate aim is to shed light on the variation in the reference to the past according to changing practices of political emancipation.Fil: Greco, Giuseppe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin
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
Myth, logos and history. The philosophical reconstruction of the past in the myth of Plato's Statesman
Full text linkEn este artículo se considera la función y el valor del mythos del Político de Platón. En primer lugar, se analiza el contexto en el que surge el relato para definir su función en el marco de la investigación diairética acerca de la definición del político. En segundo lugar, se evidencia que a la base de la formulación del mythos se encuentra una serie de relatos tradicionales a los que se aplica un método histórico-reconstructivo. Luego se resaltan las formas de razonamiento a las que los personajes del diálogo acuden para reconstruir, a partir de la tradición mítica, un relato racional y plausible. Finalmente, se argumenta que el relato, aunque no pueda alcanzar la verdad propia de los objetos de conocimiento más estables y seguros, evidencia un cierto grado de plausibilidad, fundamentada en la coherencia interna, en el respeto de una serie de principios admitidos como verdaderos y, finalmente, en su correspondencia con la tradición mítica.This article considers the function and value of the mythos in Plato's Statesman. As first, I recall the context of the story and its function within the framework of diairetic inquiry about the definition of the real politician. Secondly, I point out that the formulation of the myth is based on a series of traditional stories to which a historical-reconstructive method is applied. I then highlight the ways of reasoning used by the characters in order to reconstruct a rational and plausible account from the mythical tradition. Finally, I try to show that the story, even though it cannot reach the truth of the most stable objects of knowledge, displays a certain degree of plausibility, based on the internal coherence, on the respect of a series of principles admitted as true and, eventually, on its correspondence with the mythical tradition.Fil: Greco, Giuseppe. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades. Centro de Investigaciones María Saleme Burnichón; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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
- …
