1,655 research outputs found
Staley, Roberta
No full textcurrentAcademic Biography
BA (University of Calgary)
Diploma Journalism (Grant MacEwan)
MA Liberal Studies (Simon Fraser University)
Roberta Staley is an author, a magazine editor and writer, and a documentary filmmaker who has reported from such places as Afghanistan, Papua New Guinea, Kenya, El Salvador, Haiti, Colombia, Cambodia, South Africa, Israel, and New Zealand. She currently edits Enterprise magazine, and is a contributor to BC Business, the South China Morning Post Magazine, Ms. Magazine, Trek, the Canadian Chemical News, Corporate Knights, and Sculpture, among others. She is also a columnist for Just for Canadian Doctors/Dentists magazines. Roberta has published her first book, titled Voice of rebellion : how Mozhdah Jamalzadah brought hope to Afghanistan. It is a biography of Afghan-Canadian human rights activist Mozhdah Jamalzadah
Influenza della concentrazione di monomero sulla stereoselettività della reazione di polimerizzazione del propene promossa da sistemi Ziegler-Natta eterogenei
No full textInfluenza della concentrazione di monomero sulla stereoselettività della reazione di polimerizzazione del propene promossa da sistemi Ziegler-Natta eterogenei
No full textC-2-symmetric ansa-metallocene catalysts for propene polymerization: Stereoselectivity and enantioselectivity
No full textImportant similarities between the new homogeneous catalysts for 1-alkene polymerization based on C2-symmetric ansa-metallocenes of the 4th column and their heterogeneous Ziegler–Natta predecessors are unquestionable; in particular, the factors leading to the remarkable enantioselectivity of both catalyst classes have been proved to be strictly analogous. In the case of metallocene catalysts, however, an insidious side reaction of chain epimerization, unnoticed for a relatively long time, can undermine the stereoselectivity of the polymerization process; this recent finding and its mechanistic implications are discussed in the present paper
Highly Regioselective Transition-Metal-Catalyzed 1-Alkene Polymerizations: A Simple Method for the Detection and Precise Determination of Regioirregular Monomer Enchainments
No full textThe potentialities of this approach are illustrated for propene polymn. promoted by two well-known ansa-metallocene catalysts (cocatalyst: methylaluminoxane, MAO): the isotactic-specific rac-Me2Si(1-indenyl)2ZrCl2 (I), and the syndiotactic-specific (Me)(Ph)C(cyclopentadienyl)(9-fluorenyl)ZrCl2 (II). A series of copolymn. expts. at variable ethene-1-13C-propene feeding ratios in the presence of I/MAO or II/MAO was carried out to locate the value of ethene incorporation above which "all" 2,1-propene units are followed by an ethene one. The higher regioselectivity and regioirregular sequences of the copolymers were clearly detected by 13C NMR. The 13C NMR spectra of an isotactic polypropylene prepd. with I/MAO at 10°, a copolymer of propene contg. 2.9 mol% of ethene-1-13C prepd. with I/MAO, and an ethene-1-13C-propene copolymer (ethene content 2.5 mol%) prepd. with II/MAO, were presented
Highly Regioselective Transition-Metal-Catalyzed 1-Alkene Polymerizations: A Simple Method for the Detection and Precise Determination of Regioirregular Monomer Enchainments
No full textInterfering Effects of Growing Chain Epimerization on Metallocene-Catalyzed Isotactic Propene Polymerization
No full textThe stereoregularity of polypropylene produced with C2-symmetric group 4 ansa-metallocene catalysts results from the interplay of two competing reactions, namely isotactic monomer polyinsertion and a side process of epimerization of the polymer chain at its active end; therefore, for this class of homogeneous catalysts, at variance with the “classical” heterogeneous Ziegler−Natta ones, enantioselectivity and stereoselectivity are not (necessarily) coincident. In this paper, possible methods for the separate determination of these two parameters are introduced and applied to propene polymerization in the presence of the prototypical catalyst rac-ethylene−bis(4,5,6,7-tetrahydro-1-indenyl)ZrCl2. The results prove that the relatively poor stereoselectivity of this catalyst above room temperature is consequent primarily to chain epimerization; monomer insertion indeed is highly enantioselective up to at least 80 °C. Preliminary evidence for the existence of more than one epimerization mechanism is also presented; this complicates the measurements of enantioselectivity based on 13C NMR characterizations of d-labeled poly(propene)
Postface. Pour une esthétique hétéronome et plurielle
No full textBy discussing the essays collected in the volume, Roberta Dreon's paper focuses on the reasons that justify the very idea of a pragmatist aesthetic. This is done by considering that the association between the traditional, contemplative, disinterested, and anti-instrumental conception of aesthetic experience seems to preclude the possibility of characterizing it in practical or pragmatic terms.
The author argues that this is achieved on the one hand by a rethinking of the very notion of the "aesthetic" found in the philosophies of James and Dewey. This allows for supporting the idea that artistic practices are grounded in ordinary experience, and particularly in their aesthetic-qualitative aspects. On the other hand, the author argues that Dewey's aesthetics was convincingly pragmatist to the extent that it lucidly focused on the consequences of the autonomist conception of art and proposed a continuist, meliorist, and pluralist alternative capable of providing effective contributions to democratic and inclusive development
È possibile una teoria della razionalità? Il contributo di Hilary Putnam
No full textSecondo Putnam argomentare sulla natura della razionalità è l’attività per eccellenza dei filosofi. Sulla traccia di Putnam, l’autore esamina le principali teorie della razionalità presenti nel pensiero contemporaneo. Tali concezioni hanno il difetto di essere unilaterali, mentre la nozione di razionalità si rivela complessa, quindi una teoria della razionalità è possibile, benché non possa essere definitiva. In seguito l’autore cerca di individuare le caratteristiche fondamentali che competono alla razionalità, in opposizione tanto alla concezione positivista quanto al relativismo.According to Putnam, arguing about the nature of rationality is the typical task of philosophers. Following Putnam, in this paper the author examines the main theories of rationality to be found in contemporary thought. Whereas such views betray their own one-sidedness, the idea of rationality is very complicated. As a consequence, a theory of rationality is possible, but cannot be definitive. Furthermore, the author tries to highlight the chief features pertaining to rationality, opposing positivsm as well as relativism
First person - Roberta Besio
No full textFirst Person is a series of interviews with the first authors of a selection of papers published in Disease Models & Mechanisms (DMM), helping early-career researchers promote themselves alongside their papers. Roberta Besio is first author on 'Cellular stress due to impairment of collagen prolyl hydroxylation complex is rescued by the chaperone 4-phenylbutyrate', published in DMM. Roberta is a postdoc in the lab of Antonella Fortino at University of Pavia, Italy, investigating collagen and genetic diseases of the connective tissue
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