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Defferente tolleranza al Cd2+ di due popolazioni di Silene vulgaris (moench) garke
No full textDIFFERENTE TOLLERANZA AL Cd2+ DI DUE POPOLAZIO I DI SlLENE VULGARlS
(MOENCH) GARCIffi
A. Rivetta, A. Carnelli, M. ianotti, M. Dell'Orto, . Negrini, e ~1. Cocucci
Dipartimento di Fisiologia delle PianIe coltimle e Chimica Agraria, l:nil'enilò di .lIilor.o
Riassunto
E' nota l' esistenza di popolazioni della stessa specie adattate a crescere e riprodmsi su terreni
normali e ricchi di metalli pesanti. Tali popolazioni hanno evoluto caratteristiche morfologiche e
meccanismi biochimici e fisiologici che conferiscono tolleranza o sensibilità a questo tipo di
inquinanti. In particolare Silene vulgaris presenta particolari popolazioni tolleranti alla presenza di
Cu2+, Cd2+ e Zn2+, ma i meccanismi coinvolti rimangono incerti . Alcune evidenze indicano che
la tolleranza differenziale di tali popolazioni ai metalli pesanti risulta legata ad un diverso
assorbimento del metallo, al mantenimento dell'omeostasi ossido riduttiva della cellula, alla
sintesi e alla cinetica di espressione di peptidi (fitochelatine) in grado di chelare il metallo e
compartimentarlo nel vacuolo.
Nel presente lavoro sono state individuate e caratterizzate per alcuni parametri fisiologici due
popolazioni di Silene vulgaris cresciute su terreni situati in prossimità delle uscite a giorno di
miniere di ferro le cui scorie sono ricche di metalli pesanti (località Parre, Val Seriana, Bergamo) e
su terreni adiacenti incontaminati. Le piante ottenute dai semi delle due popolazioni erano
autofecondate ed interfecondate all'interno della stessa popolazione per tre generazioni. Per
verificare se le due popolazioni presentassero una effettiva sensibilità differenziale ai metalli
pesanti, in particolare al Cd2+, indicativo di un più generale inquinamento, le piantine ottenute dai
semi della III generazione erano trapiantate su un substrato (sabbia 87%, argilla 9%, suolo secco
all'aria 2%, torba 2%) a cui erano aggiunte quantità crescenti di CdS04' Dopo 20 giorni dal
trapianto, all'aumentare del livello di Cd2+ nel substrato la % di sopravvivenza diminuiva
leggermente nella popolazione ritenuta tollerante ed era drasticamente ridotta in quella ritenuta
sensibile, diminuendo fino al 10% in presenza di Cd2+ 893 I1mol kg- I substrato secco. Si è voluto
qu indi approfondire lo studio dei meccanismi che potevano determinare tale diversa sensibilità al
Cd2+ Le piante delle due popolazioni erano allevate per 15 giorni in coltura idroponica; dopo tale
periodo, le radici erano colorate di nero per immersione in una sospensione di carbone attivo,
permettendo in tal modo la misura dell'accrescimento delle radici. Le piante erano poi trasferite
per 3 giorni in un mezzo contenente diversi livelli di Cd2+ (O, 3, 10,30 e 100 11M). All'aumentare
della concentrazione di Cd2+, l'allungamento delle radici delle piante tolleranti era
significativamente maggiore rispetto a quello delle piante sensibili . Dopo 4 h di incubazione in
presenza di cadmio e a partire da Cd2+ 50 11M, il livello del catione nelle radici era sensibilmente
maggiore nella popolazione Cd-sensibile ri spetto alla Cd-tollerante, mentre il contenuto di metallo
nella parte epigea risultava simile. La diversa sensibilità al Cd2+ delle due popolazioni, che risulta
evidente a relativamente lungo periodo, poteva essere determinata dai diversi livelli di Cd2+ nelle
radici, probabilmente dovuto a differenti meccanismi coinvolti nell'assorbimento del Cd2+ nelle
cellule della radice, attivati già nelle prime ore di esposizione al metallo. A supporto di tale ipotesi
è stata valutata la capacità di acidificazione del mezzo come misura dell 'estrusione di protoni delle
radici delle piante appartenenti alle due popolazioni in assenza ed in presenza di Cd2+, in quanto
indice della attivazione delle funzioni di membrana. In assenza di Cd2+, le piante Cd-sensibili
acidificavano più delle Cd-tolleranti. Già dopo 2 h di incubazione in presenza di Cd2+ 100 11M,
l'acidificazione del mezzo era fonememe inibita nelle Cd-sensibili, mentre era stimolata nelle Cdtolleranti.
Questi dati sug",aeriscono che la differente capacità di estrudere H+ sia in relazione con il
diverso assorbimento di Cè--
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
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Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
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counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
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koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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