Enhanced Templating in the Crystallisation of Poly(E-caprolactone) Using 1,3:2,4-di(4-Chlorobenzylidene) Sorbitol

We show that small quantities of 1,3:2,4-di(4-chlorobenzylidene) sorbitol dispersed in poly(epsilon-caprolactone) provide a very effective self-assembling nanoscale framework which, with a flow field, yields extremely high levels of polymer crystal orientation. During modest shear flow of the polymer melt, the additive forms highly extended nano-particles which adopt a preferred alignment with respect to the flow field. On cooling, polymer crystallisation is directed by these particles. This chloro substituted dibenzylidene sorbitol is considerably more effective at directing the crystal growth of poly(epsilon-caprolactone) than the unsubstituted compound.

Winter wheat in England and Wales, 1923 - 1995: What do indices of genetic diversity reveal?

Genealogical data have been used very widely to construct indices with which to examine the contribution of plant breeding programmes to the maintenance and enhancement of genetic resources. In this paper we use such indices to examine changes in the genetic diversity of the winter wheat crop in England and Wales between 1923 and 1995. We find that, except for one period characterized by the dominance of imported varieties, the genetic diversity of the winter wheat crop has been remarkably stable. This agrees with many studies of plant breeding programmes elsewhere. However, underlying the stability of the winter wheat crop is accelerating varietal turnover without any significant diversification of the genetic resources used. Moreover, the changes we observe are more directly attributable to changes in the varietal shares of the area under winter wheat than to the genealogical relationship between the varieties sown. We argue, therefore, that while genealogical indices reflect how well plant breeders have retained and exploited the resources with which they started, these indices suffer from a critical limitation. They do not reflect the proportion of the available range of genetic resources which has been effectively utilized in the breeding programme: complex crosses of a given set of varieties can yield high indices, and yet disguise the loss (or non-utilization) of a large proportion of the available genetic diversity.

Reflections on Beckett: a centenary celebration

The essays in this collection were originally delivered as part of the Samuel Beckett lecture series at Trinity College Dublin, Samuel Beckett's alma mater. The contributors include eminent Beckett scholars such as Linda Ben-Zvi, Enoch Brater, Ruby Cohn and Stan Gontarski, theatre scholars such as Herbert Blau and Joseph Roach, practitioners such as the Irish actor, Barry McGovern, and cultural critics such as Marina Warner and Terry Eagleton. The collection sheds new light on Beckett's enigmatic theater, offering new perspectives on Beckett's use of language and silence, on his attitudes toward the body, on those who influenced him and on those he has influenced (including Suzan-Lori Parks and Femi Osofisan), and on Beckett and the art of self-collaboration. Each contributor places the playwright into a network of genealogies and legacies and his work into important historical, cultural, and aesthetic contexts. Together, the essays demonstrate Beckett's impact on theater, performance, and visual arts during the latter half of the twentieth century and serve to open up new directions for Beckett studies.