Identifying distributional characteristics in random coefficients panel data models

We study the identification of panel models with linear individual-specific coefficients, when T is fixed. We show identification of the variance of the effects under conditional uncorrelatedness. Identification requires restricted dependence of errors, reflecting a trade-off between heterogeneity and error dynamics. We show identification of the density of individual effects when errors follow an ARMA process under conditional independence. We discuss GMM estimation of moments of effects and errors, and introduce a simple density estimator of a slope effect in a special case. As an application we estimate the effect that a mother smokes during pregnancy on child's birth weight.

Robust priors in nonlinear panel data models

Many approaches to estimation of panel models are based on an average or integrated likelihood that assigns weights to different values of the individual effects. Fixed effects, random effects, and Bayesian approaches all fall in this category. We provide a characterization of the class of weights (or priors) that produce estimators that are first-order unbiased. We show that such bias-reducing weights must depend on the data unless an orthogonal reparameterization or an essentially equivalent condition is available. Two intuitively appealing weighting schemes are discussed. We argue that asymptotically valid confidence intervals can be read from the posterior distribution of the common parameters when N and T grow at the same rate. Finally, we show that random effects estimators are not bias reducing in general and discuss important exceptions. Three examples and some Monte Carlo experiments illustrate the results.

Underidentification?

We develop methods for testing the hypothesis that an econometric model is underidentified and inferring the nature of the failed identification. By adopting a generalized-method-of moments perspective, we feature directly the structural relations and we allow for nonlinearity in the econometric specification. We establish the link between a test for overidentification and our proposed test for underidentification. If, after attempting to replicate the structural relation, we find substantial evidence against the overidentifying restrictions of an augmented model, this is evidence against underidentification of the original model.

Binary choice panel data models with predetermined variables

(i) The explanatory variables are predetermined but not strictly exogenous. This includes lagged dependent variables as well as other forms of unspeci.ed feedback. (ii) Individual e1ects are allowed to be correlated with the explanatory variables. Dependence is speci.ed through the conditional expectation of the e1ects which is let to be non-parametric. We also present a GMM estimator for these models, which is consistent and asymptotically normal for .xed T and large N. We study its .nite sample properties in an autoregressive model by means of Monte Carlo simulations. Finally, as an empirical illustration, we estimate a female labour force participation equation withpredetermined children using PSID data.Publicad

«Must be Chilote»: transnational migrant life in the Patagonian territories of Chile and Argentina

Este artículo presenta avances de investigación etnográfica considerando hitos históricos en la migración transnacional de chilotes desde los años cincuenta hasta los ensamblajes actuales en lugares de la Patagonia chilena y argentina. En particular, se analizan etapas de movilidad vinculadas al auge económico en territorios australes, destacando sectores de inserción laboral en ambos lados de la frontera. Los resultados preliminares muestran las conexiones culturales reservadas a lugares de origen y residencia a través de la formación de comunidades, circulación de mercancías, extensión de significados y nuevas trayectorias migratorias interregionales. La plataforma metodológica corresponde a etnografías en movimiento derivadas de acercamientos circunstanciales en diferentes localidades de Chiloé y la Patagonia, entre diciembre de 2015 y mayo de 2017. Las reflexiones en este trabajo hacen un aporte a los estudios sobre movilidades humanas en el sur de Chile analizadas desde perspectivas multilocales, que permiten localizar continuidades culturales en la migración vividaThis article presents new ethnographical information on milestones in the history of the transnational migration of Chilotes (inhabitants of Chiloe Island, southern Chile), from the 1950s up to the assemblages existing today in different parts of Chilean and Argentinean Patagonia. In particular, we analyse stages in the development of mobility linked to the economic boom in these southern territories, highlighting sectors in which jobs were created on both sides of the border. The preliminary results show how cultural connections are retained with places of origin and residence through the formation of communities, the circulation of goods, the extension of symbolic meanings and new inter-regional migratory trajectories. The methodology used was that of ethnographies in movement derived from circumstantial approaches in different locations in Chiloe and Patagonia between December 2015 and May 2017. The reflections in this work are a contribution to studies on human mobility in southern Chile from multi-local perspectives that allow cultural continuities to be identified in the experience of migratio

Why Improved Maize (Zea mays) Varieties are Utopias in the Highlands of Central Mexico

El obetivo de este trabajo consiste en el estudio de la adopción de variedades mejoradas de maíz en los Valles alto de México a través de los resultados del Programa Especial de Producción de Maíz del Estado de México (PEPMA). El trabajo comprende dos fases: el análisis estadístico de los datos del PEPMA y dos encuestas, seguidad por un trabajo de campo con entrevistas abiertas a los agricultores participantes de la población de San Pedro la Concepción en el Valle de Toluca. Los resultados muestran que la gran mayoría de agricultores continúa sembrando sus semillas autóctonas, los híbridos o las variedades mejoradas no son opciones técnicas reales en tanto que ellas no se desmpeñan bien en las condiciones de la zona de estudio.El obetivo de este trabajo consiste en el estudio de la adopción de variedades mejoradas de maíz en los Valles alto de México a través de los resultados del Programa Especial de Producción de Maíz del Estado de México (PEPMA). El trabajo comprende dos fases: el análisis estadístico de los datos del PEPMA y dos encuestas, seguidad por un trabajo de campo con entrevistas abiertas a los agricultores participantes de la población de San Pedro la Concepción en el Valle de Toluca. Los resultados muestran que la gran mayoría de agricultores continúa sembrando sus semillas autóctonas, los híbridos o las variedades mejoradas no son opciones técnicas reales en tanto que ellas no se desmpeñan bien en las condiciones de la zona de estudio

Fission yeast α-glucan synthase Mok1 requires the actin cytoskeleton to localize the sites of growth and plays an essential role in cell morphogenesis downstream of protein kinase C function

et al.In fission yeast protein kinase C homologues (Pck1 and Pck2) are essential for cell morphogenesis. We have isolated mok1+ in a genetic screen to identify downstream effectors for Pck1/2. mok1+ is essential for viability and encodes a protein that has several membrane-spanning domains and regions homologous to glucan metabolic enzymes. mok1 mutant shows abnormal cell shape, randomization of F-actin and weak cell wall. Biochemical analysis shows that Mok1 appears to have α-glucan synthase activity. Mok1 localization undergoes dramatic alteration during the cell cycle. It localizes to the growing tips in interphase, the medial ring upon mitosis, a double ring before and dense dot during cytokinesis. Double immunofluorescence staining shows that Mok1 exists in close proximity to actin. The subcellular localization of Mok1 is dependent upon the integrity of the F-actin cytoskeleton. Conversely, overexpression of mok1+ blocks the translocation of cortical actin from one end of the cell to the other. pck2 mutant is synthetically lethal with mok1 mutant, delocalizes Mok1 and shows a lower level of α-glucan. These results indicate that Mok1 plays a crucial role in cell morphogenesis interdependently of the actin cytoskeleton and works as one of downstream effectors for Pck1/2.The initial part of this work was supported by a grant from Kyowa Hakko Co. Ltd.Peer Reviewe

Symmetrically normalized instrumental-variable estimation using panel data

We discuss the estimation of linear panel-data models with sequential moment restrictionsu sing symmetricallyn or malizedg eneralized method of moments( GMM) estimators( SNM)and limited information maximuml i kelihood( LIML)analogues These es imators are asymptotically equivalent to standardG MMb ut are invariantto normalizationan dt end to havea smallerf inite-samplbe ias, especiallyw hen the instruments are poor. We study their properties in relation to ordinary GMM and minimum distancee stimators for AR(1)model swith individual effects by mean of simulations. Finally, as empirical ilustrations, we estimate by SNM and LML employment and wage equations using panels of U.K. and Spanish firm.The first author acknowledges research funding from a CEMFIP h.D. scholarship and from the Spanish DGES, Grant PB95-0292Publicad

Learning about migration decisions from the migrants : an exercise in endogenous sampling and complementary datasets

Se investigan los determinantes del importante aumento de las migraciones intrarregionales en España desde los años ochenta, utilizando la Estadistica de Variaciones Residenciales. Se identifican las probabilidades de migracion condicionales comparando la distribucion conjunta de caracteristicas de los migrantes con la distribucion correspondiente a la poblacion total de migrantes y no migrantes, utilizando para ello la Encuesta de Poblacion Activa. La proporcion de empleo en el sector servicios, los precios de la vivienda y la educacion tienen un importante efecto positivo sobre las probabilidades de migracion intrarregionales individuales. (ob) (ad

Female labour force participation in the 1980s : the case of Spain

Este trabajo esta motivado por el gran aumento en la participacion laboral de las mujeres de edad intermedia que, al igual que en muchos otros paises, tuvo lugar en España durante la ultima decada. Desarrollamos un modelo empirico de participacion para mujeres de 25 a 44 años, utilizando datos de series temporales, en el cual las variables explicativas de educacion y fertilidad se tratan como endogenas. Consideramos participacion, educacion y fertilidad como variables que responden conjuntamente a cambios en la demanda de trabajo cualificado y a la estructura salarial. A pesar de encontrar efectos ciclicos significativos sobre la participacion, concluimos que las fuerzas dominantes que determinaron el incremento de la participacion durante el periodo muestral fueron factores estructurales que aumentaron los ingresos potenciales de las mujeres. (igg) (obh