102,257 research outputs found
Skepticism and Justification
No full textThis special issue of Synthese, titled "Skepticism and justification", contains a substantial Introduction (by Coliva, Moruzzi and Volpe), and 9 papers on topics researched by Coliva, Pritchard, Wedgwood, Avnur, Volpe, Dodd, Millar, Gerken, Kallestrup
Effetto delle poliammine sulla regolazione della proteina cinasi C.
No full textEffetto delle poliamine sulla regolazione della proteina cinasi C. Nel tentativo di contribuire al chiarimento del ruolo delle poliamine sui processi di fosforilazione intracellulari, in questa fase dell’attività di ricerca abbiamo preso in esame gli effetti delle poliamine su diversi aspetti della regolazione della proteina cinasi C (PKC), serina/treonina cinasi che si presenta in diverse forme isoenzimatiche, alcune Ca++/diacilglicerolo (DAG)/fosfolipide dipendenti, ed altre con attività indipendente dal Ca++. Dal momento che l’associazione della PKC alle membrane è il prerequisito essenziale per la risposta fisiologica dell’enzima, particolare interesse è stato rivolto allo studio dell’effetto delle poliamine sul processo di associazione della PKC alle membrane. A questo scopo abbiamo utilizzato un sistema sperimentale costituito da PKC parzialmente purificata da cervello di ratto e da liposomi, costituiti da fosfolipidi acidi, soprattutto acido fosfatidico (PA) e fosfatidilserina (PS). La PKC associata all membrane è stata saggiata quantitativamente come recettore degli esteri del forbolo cioè misurando il legame dell’enzima attivato ad un estere del forbolo radioattivo (3H-PDBu) con cui l’enzima interagisce con una stechiometria di 1:1. Esperimenti eseguiti con liposomi di composizione definita hanno permesso di stabilire che nelle condizioni in cui prevale la formazione del complesso caratterizzato da una stechiometria di legame di 3/4 molecole di PL acido/molecola di SPM si ha un’inibizione nella formazione del complesso attivo. In questo caso infatti sembra che la SPM si disponga parallelamente alla superficie del liposoma impedendo l’ulteriore legame dell’enzima. Al contrario, nelle condizioni in cui prevale la formazione del complesso caratterizzato da una molecola di SPM/molecola di PS, la poliamina sembra legarsi perpendicolarmente alla superficie delle vescicole, e mediante i gruppi amminici non coinvolti nell’interazione con i fosfolipidi legare i siti anionici dell’enzima, favorendo l’interazione della PKC con i liposomi
Possible Applications of Modern Heuristics to the Assignment of Dense Molecular Spectra
No full textG. Moruzzi, Li-Hong Xu, R. M. Lees, B. P. Winnewisser and M. Winnewisser, J. Mol. Spectrosc., 167, 156-175 (1994). W. L. Meerts, J. A. Hageman, R. Wehrens, L. M. C. Buydens and R. de Gelder, 55th Ohio State University International Symposium on Molecular Spectroscopy, June 12-16, 2000, MI03.Author Institution: Dipartimento di Fisica ``Enrico Fermi'', dell'Universit\`{a} di Pisa and INFMThe assignment of dense rovibronic spectra has constituted for years, and continues to constitute, a great challenge to the molecular spectroscopist. This is particularly true when the selection rules of the molecule are not very stringent, and in the presence of large-amplitude vibrational modes. The availability of powerful desktop computers has lead to the development of interactive assignment methods, like the use of spreadsheets and the Ritz , and, more recently, to the first attempts to completely automate the interpretation of these spectra. Independently, during the last four decades there has been a growing interest in algorithms which rely on analogies to natural processes. These include, notably, simulated annealing, neural networks, genetic algorithms and ant algorithms. Most of these algorithms can solve complex maximization/minimization problems, notably minimization. A first application of genetic algorithms to molecular spectroscopy was presented by W. L. at this conference two years ago. In this contribution we discuss the possibility of exploiting one of the origins of the spectral complexity, namely the presence of non-stringent selection rules, for assigning a spectrum by minimizing the number of levels compatible with a given set of spectral lines (combinatorial minimization). Some preliminary results on artificial sets of more than 2 000 lines will be presented. The effects of experimental accuracy, and the possibility of searching for constrained minima, will be discussed
Guest Editors' Preface
No full textThe preface to Discipline filosofiche special issue on "Knowledge and Justification" provides a background to the eight articles collected therein and a brief summary of each
Vibrationally Excited Level Identification and FIR Laser Line Prediction by the "Ritz" and "LaseRitz" Programs
No full text G. Moruzzi and Li-Hong Xu, Ohio State University 49th International Symposium on Molecular Spectroscopy, TD04, p. 122 (1994).Author Institution: Università di Pisa, Piazza Torricelli 2, I-56100 Pisa, Italy; National Institute of Standards and Technology, Gaithersburg, MD 20899 U.S.A.Following last year's Columbus , we have continued our work on an interactive computer program for automating assignment of the Fourier-Transform methanol spectrum. Two new features have been developed. (1) A new routine has been incorporated in the Ritz program for the identification of small-amplitude vibrationally excited levels starting from the known energies of the ground-vibrational levels. We have been testing this routine in the region for . (2)A new LaseRitz program has been written for predicting FIR laser lines using known energies of the ground and the vibrationally excited levels. The simplified float chart of the interactive program is presented below
Introduction: Perspectives on Post-Truth
No full textThis opening piece of the collection 'Perspectives on Post-Truth' aims to accomplish three tasks. First, and foremost, it highlights the issue’s distinctive feature, namely its variegated approach to post-truth. The leading idea in assembling it has been to draw on different methodologies, theoretical approaches, and competences, in order to gain a finegrained understanding of the post-truth condition and to develop an effective toolkit to address the most pressing challenges it poses to our societies. The underlying conviction is that a variegated approach is required by the multifaceted nature of the post-truth condition. The curious reader willing to venture through the issue will thus be exposed to different perspectives on post-truth: some pieces address it from a traditional epistemological perspective, others explore post-truth from the perspective of social epistemology, and still others adopt a semiotic perspective. In light of this multiplicity of perspectives, the second task of this piece has been to provide a brief thematic overview of the key issues and perspectives in order to illustrate the overall narrative of the project. The third and final task has been to give a detailed synopsis of each
contribution so that the reader will know precisely what to expect from it
Assertion, Belief and Disagreement: A Problem for Truth-Relativism
No full textThis chapter argues that MacFarlane's truth-relativism faces two problems. First, it cannot explain the existence of disputes over assessment-sensitive propositions because it does not have a viable notion of disagreement. Second, it entails the idea that knowledge of the truth-relativist thesis in the context of a dispute is dialectically inhibiting: the truth relativist is committed to an ignorance theory, for the speakers who take part, to a dispute on matters of taste
Truth relativism and Evans' challenge
No full textIn this paper I develop a version of Evans’ challenge for MacFarlane’s assessment-sensitive relativism. The argument is meant to show that, contrary to MacFarlane’s intentions, the correctness of an assertion is a relative matter if the area of discourse has an assessment-sensitive semantics. Thus MacFarlane’s truth-relativism is an inherently unstable doctrine for it is unclear how we should behave in order to achieve the goal of an assertion
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