1,720,987 research outputs found
Endogenous Business Cycles and Hysteresis. A Post-Keynesian, Agent-Based Approach
No full textLa teoria neoclassica si è sviluppata storicamente intorno al concetto di equilibrio (generale o parziale), considerato nel lungo periodo stabile e indipendente dalle fluttuazioni cicliche della domanda aggregata. L’attenzione crescente verso le teorie della dipendenza dal percorso e, in particolare, lo sviluppo del concetto di isteresi in ambito economico rimettono in discussione il metodo analitico tradizionale, svalutando l’interesse e la validità teorica del concetto di equilibrio neoclassico, con le sue proprietà di stabilità. Questa tesi si concentra sul modello di isteresi sviluppato originariamente in Fisica. Lungi dal promuovere un approccio scientifico esatto per l’analisi economica, l’intento è quello di analizzare le conseguenze di aggiustamenti non lineari e discontinui degli investimenti sul ciclo economico e sulle traiettorie di crescita di lungo periodo, sfruttando le proprietà dinamiche del modello di isteresi. Facendo riferimento al paradigma teorico post-keynesiano e alla metodologia ad agenti, viene qui sviluppato un modello teorico macroeconomico capace di generare fluttuazioni irregolari intorno a equilibri transitori, vale a dire equilibri che si stabiliscono spontaneamente sulla base dell’evoluzione storica del sistema. In questo quadro teorico e analitico, le conclusioni tradizionali della teoria post-keynesiana riguardo agli effetti della distribuzione del reddito sul grado di utilizzo della capacità produttiva e sul tasso di crescita di lungo periodo ne escono rinforzate. Inoltre, le politiche espansive della domanda riconquistano un ruolo centrale nel guidare l’economia verso il pieno utilizzo delle risorse produttive.The neoclassical theory developed historically around the concept of (partial or general) equilibrium, by assuming its long run stability and independence from monetary and real fluctuations. The growing emphasis on path-dependence and, particularly, on the concept of hysteresis calls into question the traditional method, by rejecting the theoretical validity of the neoclassical equilibrium and its related stability properties. This thesis focuses on the model of “genuine” hysteresis, which first developed in the field of physics and recently extended its application to economic phenomena. Far from suggesting an appropriation of the methods that are typical of “hard” sciences, the aim is to analyse the consequences of discontinuous and hysteretic investment decisions on business cycles and long run trajectories. By relying on the Post Keynesian theory of growth and distribution, and the multi-agent methodological approach, this thesis develops a macroeconomic theoretical model that is able to generate non-linear business cycles around transitory equilibria, which are fully endogenous and historically determined according to the specific adjustment path. This theoretical framework confirms and reinforces the traditional Post Keynesian implications of income inequalities on the degree of utilization of productive capacity and on long run growth. Moreover, expansionary demand policies regain a central role in driving the economy towards the full employment of productive resources
Creep Resistance Properties of a Phosphorus-Doped/Oxygen-Free Copper-Silver Alloy: Experimental Results and Empirical Model Application
No full textThe purpose of this work is the study of creep behavior for a phosphorus-doped oxygen-free copper-silver alloy at low temperatures. Experimental tests at different stress and temperature levels will be performed and analyzed in comparison with the equivalent failure tests for a pure ETP copper. The obtained creep curves will be fitted in an empirical model based on the continuum damage mechanics so as to determine material constants with the aim to predict new
curves at different stress conditions and analyze the rupture strain and time data without the need of additional experimental results. Strain ratio determined during experimental tests has been also proven by a physical model which considers the interested deformation mechanism
Creep fatigue crack growth and fracture mechanisms of T/P91 power plant steel
Full text linkHigh temperature assessment of crack like defects in power plant components is one of the most important task to ensure high energy conversion efficiency. Creep fatigue crack growth tests for P91 power plant steel, conducted at 600 degrees C on standard C(T) specimens with 0.1, 1 and 10 h hold times, are presented. Microscopic features of the creep fatigue damage were observed along the crack path, on polished and etched cross sections of the tested specimens. The dominant damage mechanism is the formation of microvoids and microcracks associated with the crack tip, due to the creep effect during the hold time. In order to predict the experimentally measured crack growth rate a simple summation rule is used. The superposition of fatigue crack growth rate and creep crack growth rate, experimentally obtained on the same batch of material used for creep fatigue crack growth tests, well describes the behaviour under creep fatigue loading
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
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
sophisticated methods
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
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