1,721,048 research outputs found
Système de régressions empilées et panel incomplet : un tour d'horizon
No full textSystem kombinierter Regressionen und unvollständiges Panel: ein Uberblick,
von Marc Ivaldi, Michel Simioni.
In diesem Artikel werden die üblichen Methoden zur Schätzung eines Systems kombinierter Regressionen dargestellt, wobei zunächst der Fall unvollständiger Panels unter besonderer Berücksichtigung der Probleme infolge von Spezifizierungsfehlern erörtert wird: Heteroskedastizität und Nichtbeachtung der Orthogonalitätsbedingungen zwischen exogenen Variablen und individu'ellen Effekten.The Pooled Regression System and Incomplete Panel Data: An Overview,
by Marc Ivaldi, Michel Simioni.
This memo gives the usual methods for estimating a pooled regression system, first considering the example of incomplete panel data, laying particular emphasis on errors in specification: i.e. heteroscedasticity and the disregard of the conditions of orthogonality between exogenous variables and individual effects.Système de régressions empilées et panel incomplet : un tour d'horizon,
par Marc Ivaldi, Michel Simioni.
Cette note présente les méthodes habituelles d'estimation d'un système de régressions empilées, en considérant d'abord le cas de panels incomplets, et en accordant une attention particulière aux problèmes d'erreurs de spécification : hétéroscédasticité et non-respect des conditions d'orthogonalité entre variables exogènes et effets individuels.Sistema de regresiones apiladas y panel incomplète. Apreciación de conjunto,
por Marc Ivaldi , Michel Simioni.
En este artículo se presentan los métodos comentes de evaluación de un sistema de regresiones apiladas, considerando en primer lugar el caso de paneles incompletos y poniendo una atención particular a los problemas de errores de espetificación: heterosedasticidad e incumplimiento de las condiciones de ortogonalidad entre variables exógenas y efectos individuales.Ivaldi Marc, Simioni Michel. Système de régressions empilées et panel incomplet : un tour d'horizon. In: Économie & prévision, n°105, 1992-4. pp. 97-107
Pricing of scientific journal and market power
Get PDFWe analyze the empirical relationship between journal prices, their quality measured by their citation counts, their age, as well as conduct of publishers. The database covers 22 scientific fields and over 2600 among the most highly reputed and cited journals in 2003. We show that (a) for-profit journals charge roughly 3 times more than journals run by scientific societies; (b) the number of citations has a positive impact on prices; (c) there are large differences in prices across fields that vary from 1 and 6; these are highly (and positively) correlated with the degree of concentration in the industry.
La demande d'énergie des industries laitières : une analyse microéconomique
No full textDer Energiebedarf der Milchwirtschaftsbetriebe : eine mikroökonomische Analyse,
von Alain Bousquet, Marc Ivaldi, Norbert Ladoux.
Dieser Artikel befasst sich mit der empirischen Analyse der Substituierbarkeit von Energieformen in Milchwirtschaftsbetrieben. Er zielt darauf ab, ein Funktionssystem hinsichtlich der Nachfrage nach Energiefaktoren zu schätzen und den Substituierbarkeitsgrad zwischen jeder dieser Formen zu erfassen, um die Entwicklung der Struktur des gesamten Energieverbrauchs besser zu verstehen. Die in der Stichprobe beobachtete Nullausgabensituation erfordert bei der Spezifikation des Modeils zuallererst unter theoretischem sodann unter ökonometrischem Gesichtspunkt besondere Aufmerksamkeit. Das vorgeschlagene Modell weist ähnliche Merkmale auf wie die Modelle mit qualitativen Variablen vom verallgemeinerten Tobit-Typ.The energy demands in dairy industries : a micro-economic analysis,
by Alain Bousquet, Marc Ivaldi, Norbert Ladoux.
An empirical analysis examines substitution opportunities for various forms of energy in the dairy industry. First, we estimate a demand function system for energy factors in order to grasp their substituability. It is then possible to understand the trends in the structure of the energy consumption. Zero expenditures in the sample require a special treatment when the model is specified. And this is true for two different stages : the theoretical one as well as the econometric one. The model is similar to qualitative variable models such as the general Tobit model.La demande d'énergie des industries laitières : une analyse microéconomique,
par Alain Bousquet, Marc Ivaldi, Norbert Ladoux.
Cet article s'intéresse à l'analyse empirique des possibilités de substitutions entre formes d'énergie, pour les entreprises du secteur des industries laitières. L'objectif est d'estimer un système de fonction de demande de facteurs énergétiques et d'appréhender le degré de substituabilité entre chacune de ces formes, et, ainsi, de mieux comprendre l'évolution de la structure de la consommation totale d'énergie. La présence de dépenses nulles dans l'échantillon requiert une attention particulière lors de la spécification du modèle, au point de vue théorique tout d'abord et économétrique ensuite. Le modèle proposé s'apparente aux modèles à variables qualitatives du type Tobit généralisé.La demanda de energia de las industrias lecheras : un análisis microeconómico,
por Alain Bousquet, Marc Ivaldi, Norbert Ladoux.
En este artículo se procede a un análisis empírico de las posibilidades de substitución entre formas de energía para las empresas del sector de las industrias lecheras. Tiene por objetivo estimar un sistema de función de demanda de factures energéticos y aprehender el grado de substituibilidad entre cada una de estas formas y, de este modo, entender mejor la evolución de la estructura del consumo total de energía. La existencia de gastos nulos en la muestra requière una atenciôn particular cuando se especifica el modelo, ya sea teóricamente o econométricamente. El modelo propuesto se parece a los modelos de variables cualitativas del tipo Tobit generalizado.Bousquet Alain, Ivaldi Marc, Ladoux Norbert. La demande d'énergie des industries laitières : une analyse microéconomique. In: Économie & prévision, n°91, 1989-5. Etudes sectorielles. pp. 75-90
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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