1,720,963 research outputs found
A micro-macro approach to commodity market analysis:risk, structural modelling and forecasting
Full text linkQuesto studio concerne l’analisi dei mercati delle materie prime da una prospettiva sia micro che macroeconomica e si compone di tre parti.
Nella prima parte vengono analizzate le strategie di gestione ex-ante del rischio, in particolare la selezione di un portafoglio diversificato di colture, messe in atto in paesi poveri da famiglie produttrici fortemente dipendenti per la loro sussistenza dalla produzione di materie prime agricole. A tal fine, viene specificato un modello di portafoglio da cui si ottengono stime strutturali dei parametri relativi alla tecnologia, al consumo e alle preferenze verso il rischio dei produttori. Il modello è stimato utilizzando dati longitudinali da un campione di produttori di caffè in Etiopia.
La seconda parte concerne la modellizzazione dei mercati delle materie prime in un contesto di aspettative razionali. L’attenzione è posta in particolare sulle colture pluriennali e viene specificato un modello globale per il mercato del cacao che incorpora la domanda di stoccaggio per fini speculativi. Dal modello strutturale si deriva una forma ridotta nelle variabili prezzo e stock, utilizzando due nuove variabili costruite per rappresentare eccessi di offerta di breve e lungo periodo. Viene quindi illustrata la derivazione analitica di restrizioni che emergono dall’utilizzo dell’ipotesi di aspettative razionali. Inoltre, viene proposta in un contesto deterministico un’analisi di equilibrio del mercato, utilizzando la soluzione in aspettative razionali del modello rispetto al variabile prezzo, al fine di studiare l’evoluzione del mercato in risposta a shock esogeni.
Nella terza parte, la forma ridotta nelle variabili prezzo e stock, derivata in precedenza da una versione di breve periodo del modello, viene stimata utilizzando dati annuali relativi al mercato del cacao e le restrizioni derivanti dall’ipotesi di aspettative razionali vengono testate. Le stime ottenute attraverso il metodo dei momenti generalizzato (GMM) vengono quindi confrontate con quelle ottenute da un modello vettoriale autoregressivo (VAR) che presenta una specificazione equivalente.This work concerns the analysis of primary commodity markets from both a micro and macro perspective and is composed of three parts.
In the first part, we investigate how rural households in poor countries, depending for their livelihood on crop production, cope ex-ante with risk through a strategy of a diversified portfolio of crops. To this end, a portfolio model of production is set up from which structural estimates of risk preference and technology parameters are derived. The model is fit to longitudinal data from a sample of coffee producers in Ethiopia.
The second part is concerned with the modelling of commodity markets within a rational expectations approach. A special emphasis is placed on perennial crops and a world model for the cocoa market is specified, accounting for speculative stockholding. From the structural model a solved form in price and stocks is derived, using two constructed variables capturing excess supply in the short and long term. The derivation of restrictions stemming from the hypothesized rational expectations by stockholders is then illustrated. Furthermore, an equilibrium analysis of the model is carried out using the price rational expectations solution, in order to investigate the qualitative response of the system to shocks.
In the third part, the reduced form in price and stocks previously derived from a short-run version of the model is estimated using annual data on the cocoa market and the rational expectations restrictions are tested. The estimates obtained using the generalized method of moments (GMM) are then compared with those obtained from a restricted vector autoregressive (VAR) model presenting a matching specification
Fiscal rules to tame the political budget cycle: evidence from italian municipalities
Full text linkThe paper provides evidence that fiscal rules can limit the political budget cycle. It focuses on the
application of the Italian fiscal rule at the sub-national level over the period 2004-2006 and shows
that: 1) municipalities are subject to political budget cycles in capital spending; 2) the Italian sub-national
fiscal rule introduced in 1999 has been enforced by the central government; 3)
municipalities subject to the fiscal rule show more limited political budget cycles than
municipalities not subject to the rule. In order to identify the effect, we rely on the fact that the
domestic fiscal rule does not apply to municipalities below 5,000 inhabitants. We find that the
political budget cycle increases real capital spending by about 35 percent on average in the years
prior to municipal elections and that the sub-national fiscal rule reduces these figures by about
two thirds
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
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