A nonparametric analysis of the Cournot model

An observer makes a number of observations of an industry producing a homogeneous good. Each observation consists of the market price, the output of individual firms and perhaps information on each firm's production cost. We provide various tests (typically, linear programs) with which the observer can determine if the data set is consistent with the hypothesis that firms in this industry are playing a Cournot game at each observation. When cost information is wholly or partially unavailable, these tests could potentially be used to derive cost information on the firms. This paper is a contribution to the literature that aims to characterize (in various contexts) the restrictions that a data set must satisfy for it to be consistent with Nash outcomes in a game. It is also inspired by the seminal result of Afriat (and the subsequent literature) which addresses similar issues in the context of consumer demand, though one important technical difference from most of these results is that the objective functions of firms in a Cournot game are not necessarily quasiconcave

Variability of cranial morphometrical traits in Suffolk Down Sheep

The widespread use of measures and indices associated with the head for racial analysis suggests that such measures have a strong relationship with the underlying bone structure. Few studies analyse the variability of the bones of the head and the relationship with their external expression. The objective of this work was to identify and measure the magnitudes of the main skull parameters in Suffolk Down adult sheep. This study was carried out on sixteen adult Suffolk Down sheep skulls at INIA Butalcura. Their skeletons were obtained and digital morphometry was performed. Each skull was photographed from dorsal, ventral, lateral and nuchal views with a total of 28 parameters evaluated (10 dorsal, 5 ventral, 6 lateral and 6 nape). The results indicate that the externally observable variability in the cranial zone of a sheep cannot be extrapolated to the rest of the bony components of the cranial zone, either in length, width or height. It was observed that the variability of a cephalic dimension can be contrasted with the variability of individual bones that participate in a certain dimension as part of a plasticity adjustment mechanism independent of the genetic variability of each bone separately. The cranial dimensions are still useful in defining the productive potential of a sheep population; however, they should be taken cautiously for racial definitions, where the individual variability of the bones could be a better reflection of the genetic structure of the population and the dimensionality could be biased by adaptive plasticity

Individually-rational collective choice

There is a collection of exogenously given socially-feasible sets, and, for each one of them, each individual in a group chooses from an individually-feasible set. The fact that the product of the individually-feasible sets is larger than the socially-feasible set notwithstanding, there arises no conflict between individual choices. Assuming that individual preferences are random, I characterize rationalizable collective choices

Evaluación de los ingresos, empleo, diversidad y captura de carbono en algunas fincas de la cuenca del río la vieja

En 18 fincas del municipio de Alcalá se evaluaron ingresos, empleo, diversidad y captura de carbono. Esto se realizó por medio del estudio de perfil de pobreza que identificó el tipo de empleo y el acceso a los recursos, flujos de caja para el primer semestre de 2005, datos sobre macrofauna edáfica y almacenamiento de carbono en el suelo, y conocimiento de los propietarios o administradores sobre proyectos institucionale

Evaluación de las estrategias productivas de algunos sistemas campesinos en un área del municipio de alcalá, valle del cauca

En algunas fincas del municipio de Alcalá se evaluó la estructura económica y los procesos de gestión de algunos recursos. Esto se logró por medio de la descripción de los subsistemas de los predios, la construcción de balances económicos, la valoración de los bienes de autoconsumo y la categorización de las fincas de acuerdo con la metodología de líneas de pobreza que utiliza el DANE. Esto permitió demostrar que en las zonas rurales existen diferentes estrategias productivas que varían de acuerdo con la disponibilidad de terreno y capital; y a los valores relacionados con la satisfacción personal y la tradición familiar de cada productor

Evaluación de las estrategias productivas de algunos sistemas campesinos en un área del municipio de alcalá, valle del cauca

En algunas fincas del municipio de Alcalá se evaluó la estructura económica y los procesos de gestión de algunos recursos. Esto se logró por medio de la descripción de los subsistemas de los predios, la construcción de balances económicos, la valoración de los bienes de autoconsumo y la categorización de las fincas de acuerdo con la metodología de líneas de pobreza que utiliza el DANE. Esto permitió demostrar que en las zonas rurales existen diferentes estrategias productivas que varían de acuerdo con la disponibilidad de terreno y capital; y a los valores relacionados con la satisfacción personal y la tradición familiar de cada productor

Raman phonons as a probe of disorder, fluctuations and local structure in doped and undoped orthorhombic and rhombohedral manganites

We present a rationalization of the Raman spectra of orthorhombic and rhombohedral, stoichiometric and doped, manganese perovskites. In particular we study RMnO3 (R= La, Pr, Nd, Tb, Ho, Er, Y and Ca) and the different phases of Ca or Sr doped RMnO3 compounds as well as cation deficient RMnO3. The spectra of manganites can be understood as combinations of two kinds of spectra corresponding to two structural configurations of MnO6 octahedra and independently of the average structure obtained by diffraction techniques. The main peaks of compounds with regular MnO6 octahedra, as CaMnO3, highly Ca doped LaMnO3 or the metallic phases of Ca or Sr doped LaMnO3, are bending and tilt MnO6 octahedra modes which correlate to R-O(1) bonds and Mn-O-Mn angles respectively. In low and optimally doped manganites, the intensity and width of the broad bands are related to the amplitude of the dynamic fluctuations produced by polaron hopping in the paramagnetic insulating regime. The activation energy, which is proportional to the polaron binding energy, is the measure of this amplitude. This study permits to detect and confirm the coexistence, in several compounds, of a paramagnetic matrix with lattice polaron together with regions without dynamic or static octahedron distortions, identical to the ferromagnetic metallic phase. We show that Raman spectroscopy is an excellent tool to obtain information on the local structure of the different micro or macro-phases present simultaneously in many manganites.Comment: Submitted to PR

Self-trapped Exciton and Franck-Condon Spectra Predicted in LaMnO3_3

Because the ground state has cooperative Jahn-Teller order, electronic excitations in LaMnO$_3$ are predicted to self-trap by local rearrangement of the lattice. The optical spectrum should show a Franck-Condon series, that is, a Gaussian envelope of vibrational sidebands. Existing data are reinterpreted in this way. The Raman spectrum is predicted to have strong multiphonon features.Comment: 5 pages with two embedded postscript figure

Amerind Ancestry, Socioeconomic Status and the Genetics of Type 2 Diabetes in a Colombian Population

The “thrifty genotype” hypothesis proposes that the high prevalence of type 2 diabetes (T2D) in Native Americans and admixed Latin Americans has a genetic basis and reflects an evolutionary adaptation to a past low calorie/high exercise lifestyle. However, identification of the gene variants underpinning this hypothesis remains elusive. Here we assessed the role of Native American ancestry, socioeconomic status (SES) and 21 candidate gene loci in susceptibility to T2D in a sample of 876 T2D cases and 399 controls from Antioquia (Colombia). Although mean Native American ancestry is significantly higher in T2D cases than in controls (32% v 29%), this difference is confounded by the correlation of ancestry with SES, which is a stronger predictor of disease status. Nominally significant association (P<0.05) was observed for markers in: TCF7L2, RBMS1, CDKAL1, ZNF239, KCNQ1 and TCF1 and a significant bias (P<0.05) towards OR>1 was observed for markers selected from previous T2D genome-wide association studies, consistent with a role for Old World variants in susceptibility to T2D in Latin Americans. No association was found to the only known Native American-specific gene variant previously associated with T2D in a Mexican sample (rs9282541 in ABCA1). An admixture mapping scan with 1,536 ancestry informative markers (AIMs) did not identify genome regions with significant deviation of ancestry in Antioquia. Exclusion analysis indicates that this scan rules out ∼95% of the genome as harboring loci with ancestry risk ratios >1.22 (at P < 0.05)