The Genotype of the Endosperm and Embryo as It Influences Vivipary in Maize

The development of the maize seed is dependent on the orderly unfolding of events in which each component of the developing caryopsis has a particular role to play. The ultimate control of these events must depend upon numerous genes, which if altered will interfere with normal development. Many mutants of this type have been described, ranging from those which produce relatively slight alteration in the caryopsis to those which prevent practically all development. Among those producing relatively slight changes are mutants which give rise to premature germination. The seeds of these mutants develop normally until late in ontogeny. During the early dough stage the plumule begins to elongate, and the seeds germinate while still attached to the ear. Such mutants have been called viviparous

Do peer Groups Matter? Peer Groups versus Schooling Effects on Academic Attainment

In this paper we estimate an educational production function. Educational attainment is a function of three types of inputs: peer group, parental and schooling. We find that conventional measures of school quality are not good predictors for academic attainment, once we control for peer group effects. Parental qualities also have strong effects on academic atainment. This academic attainment is then a key determinant of subsequent labour market success, as measured by earnings.

Factor Residuals in SUR Regressions: Estimating Panels Allowing for Cross Sectional Correlation

This paper describes a method for estimating panels by imposing a factor structure on the residuals. The method allows SUR estimation of panel models by providing a full-rank estimator of the system covariance matrix when the usual estimate is rank-deficient. We charactersie completely the circumstances when this is possible. When the usual estimator is of full rank, our procedure provides a more parsimonious representation of the covariance matrix, which can lead to efficiency gains in finite samples. Monte Carlo analysis of convergence regressions and PPP regressions in the Heston-Summers data-set indicates that the proposed estimator has better performance in terms of RMSE and bias than standard panel or SUR estimators (where available), as well as offering unbiased inference.Panel data, cross sectional correlation, factor analysis

Unique equilibrium states for some intermediate beta transformations

We prove uniqueness of equilibrium states for subshifts corresponding to intermediate beta transformations with $\beta > 2$ having the property that the orbit of 0 is bounded away from 1

Pre-School Education and Attainment in the NCDS and BCS

This paper considers the effect of how children pass time before entrance to school on attainment in primary school. We find in NCDS data that children perform marginally better at seven and eleven if they spent time with their mother, or at a pre-school, rather than in informal care. This holds when one controls for parental education, social class, and assessed parental interest in the child's education, as well as the quality of the peer group. In the BCS, however, time spent in nurseries effected no improvement in maths at ten as compared to time in informal care and pre-school children were performing much worse in reading. This worse performance was traceable to reduced vocabulary at five. Pre-school children were more advanced in copying at five relative to children in informal care but, while copying is a good predictor of scores in both maths and reading at ten, this advancement had been offset by then.

Disjointness for measurably distal group actions and applications

We generalize Berg's notion of quasi-disjointness to actions of countable groups and prove that every measurably distal system is quasi-disjoint from every measure preserving system. As a corollary we obtain easy to check necessary and sufficient conditions for two systems to be disjoint, provided one of them is measurably distal. We also obtain a Wiener--Wintner type theorem for countable amenable groups with distal weights and applications to weighted multiple ergodic averages and multiple recurrence.Comment: 28 page

Minimum Wages and Employment

This paper investigates the effect of minimum wages on employment using a panel of US state-based data. We estimate a minimalist dynamic version of the specification implied by neo-classical theory. We find statistically and economically significant effects of minimum wages on youth employment. Unlike many other studies we find also significant effects on aggregate state employment. These results re-establish the conventional wisdom as existing before the work of Card-Krueger-Katz. The paper meets the methodological criticisms of this sort of panel study made by CKK. An important econometric innovation in this paper is to produce estimates allowing for cross-sectional correlation, which offers unbiased inference and potential efficiency gains.Minimum wages, panel data, cross sectional correlation, factor analysis.