Repository Steering Groups

A well-chosen, well-informed and committed Steering Group can make an important contribution to the sustained success of a repository. This Briefing Paper highlights some of the issues for consideration when planning the role, remit and composition of a repository Steering Group

Microdosimetric concepts relevant to HZE-particles

The biological effectiveness of HZE-particles i s determined by the extreme microscopic concentrations of energy transfer in the vicinity of the particle tracks. The concept of linear energy transfer fails to describe this situation adequately. The more rigorous microdosimetric concepts are presented. A simplified treatment, based on the radial distribution of energy around the track core, is then considered

Old Remedies in the Biotechnology Age: Moore v. Regents

The California Supreme Court, by excluding a potential remedy, has eliminated many concerns generated by a lower court decision resolving rights to the cell line derived from John Moore\u27s spleen. Yet, the Supreme Court gave little attention to remedies that remain. The authors argue that a constructive trust, a remedy of considerable vintage and great flexibility, could be applied to achieve a just result in such circumstances without affecting the biotechnology world at large

Intradomain phase transitions in flexible block copolymers with self-aligning segments

We study a model of flexible block copolymers (BCPs) in which there is an enlthalpic preference for local alignment, among like-block segments. We describe a generalization of the self-consistent field theory (SCFT) of flexible BCPs to include inter-segment orientational interactions via a Landau-DeGennes free energy associated with a polar or nematic order parameter for segments of one component of a diblock copolymer. We study the equilibrium states of this model numerically, using a pseudo-spectral approach to solve for chain conformation statistics in the presence of a self-consistent torque generated by inter-segment alignment forces. Applying this theory to the structure of lamellar domains composed of symmetric diblocks possessing a single block of "self-aligning", polar segments, we show the emergence of spatially complex segment order parameters (segment director fields) within a given lamellar domain. Because BCP phase separation gives rise to spatially inhomogeneous orientation order of segments even in the absence of explicit intra-segment aligning forces, the director fields of BCPs, as well as thermodynamics of lamellar domain formation, exhibit a highly non-linear dependence on both the inter-block segregation ($\chi N$) and the enthalpy of alignment ($\varepsilon$). Specifically, we predict the stability of new phases of lamellar order in which distinct regions of alignment coexist within a single mesodomain, and which spontaneously break the symmetry of the lamella pattern of composition in the melt via in-plane tilt of the director in the centers of the like-composition domains. We show further that, in analogy to a Freedericksz transition in confined nematics, that the elastic costs to reorient segments within the domain, as described by Frank elasticity, increase the threshold value $\varepsilon$ needed to induce this intra-domain phase transition

DEFINING THE 'SAVING' IN AGRICULTURE WATER WHEN IRRIGATION TECHNOLOGY IS A CHOICE VARIABLE: THE CASE OF THE KLAMATH BASIN

Increasing demand for water in the environment has increased the cost of irrigation water in agriculture leading to the adoption of water saving irrigation technologies, reducing agricultural return flows. However, when agricultural return flows are a source of environmental supply 'savings' soon disappear because of the reduced agricultural return flowsResource /Energy Economics and Policy,

The status of music education in the public junior high schools of Massachusetts as of the year 1945-1955

Thesis (Ed.M.)--Boston Universit

Absorption and Screening in Phycomyces

In vivo absorption measurements were made through the photosensitive zones of Phycomyces sporangiophores and absorption spectra are presented for various growth media and for wavelengths between 400 and 580 mµ. As in mycelia, ß-carotene was the major pigment ordinarily found. The addition of diphenylamine to the growth media caused a decrease in ß-carotene and an increase in certain other carotenoids. Growth in the dark substantially reduced the amount of ß-carotene in the photosensitive zone; however, growth on a lactate medium failed to suppress ß-carotene in the growing zone although the mycelia appeared almost colorless. Also when diphenylamine was added to the medium the absorption in the growing zone at 460 mµ was not diminished although the colored carotenoids in the bulk of the sporangiophore were drastically reduced. Absorption which is characteristic of the action spectra was not found. Sporangiophores immersed in fluids with a critical refractive index show neither positive nor negative tropism. Measurements were made of the critical refractive indices for light at 495 and 510 mµ. The critical indices differed only slightly. Assuming primary photoreceptors at the cell wall, the change in screening due to absorption appears too large to be counterbalanced solely by a simple effect of the focusing change. The possibility is therefore advanced that the receptors are internal to most of the cytoplasm; i.e., near the vacuole

The Silent Epidemic: Perspectives of High School Dropouts

Presents findings from a survey that examines why some students do not complete their high school education, and what academic and personal supports would have helped them stay in school. Includes recommendations for improving graduation rates