Scholarly communication in an electronic environment: problems and challenges

Thanks to remarkable feats of international cooperation over the last 50 years librarians have produced and maintained a string of standards which collectively have made the identification of almost any published item a straightforward task (UBC), and have changed interlibrary document supply from a peripheral operation to a core activity (UAP). The system runs so smoothly that it is taken for granted and its lessons are not being used to inform discussions on the emergence of exactly the same issues in the electronic environment. The Internet is seen as a great and liberating development, but it is not a neutral one, and it requires very substantial international effort if it is to be made usable for sustained scholarly communication rather than short-term gratification. The preservation and archiving of electronic information has only just begun to surface as a very complex issue. An electronic environment is being created which is inimical to scholarship and which is largely being ignored by commercial and entertainment forces that are irrelevant to the scholarly process. A much more active approach from the library profession is required

Information policy for a new millennium

Previous revolutions, the Agrarian and Industrial, are examined and their features compared with the Information Revolution. Lessons are drawn from the comparison and a range of global issues identified. The nature of the Internet is considered and its pretensions argued to be inflated. The role of the state in developing an information society is discussed. A national information policy is identified as a feature and its application in and implications for Scotland are considered. Key features of an Internet culture are indicated and discussed, with lessons and conclusions for social development within the information society presented

Liquid bridging of cylindrical colloids in near-critical solvents

Within mean field theory, we investigate the bridging transition between a pair of parallel cylindrical colloids immersed in a binary liquid mixture as a solvent which is close to its critical consolute point $T_c$. We determine the universal scaling functions of the effective potential and of the force between the colloids. For a solvent which is at the critical concentration and close to $T_c$, we find that the critical Casimir force is the dominant interaction at close separations. This agrees very well with the corresponding Derjaguin approximation for the effective interaction between the two cylinders, while capillary forces originating from the extension of the liquid bridge turn out to be more important at large separations. In addition, we are able to infer from the wetting characteristics of the individual colloids the first-order transition of the liquid bridge connecting two colloidal particles to the ruptured state. While specific to cylindrical colloids, the results presented here provide also an outline for identifying critical Casimir forces acting on bridged colloidal particles as such, and for analyzing the bridging transition between them.Comment: 23 pages, 12 figure

Replacement of PBNA in HB and HC polymers used in SRM propellant and liner

The antioxidant phenyl-beta-naphthylamine (PBNA) was used in both HB and HC polymers. The sole (domestic) supplier of PBNA has withdrawn this product from the market, primarily because of suspected health hazards. Commercially available substitute(s) were selected and qualified for use in the two polymers

Effective interaction between a colloid and a soft interface near criticality

Within mean-field theory we determine the universal scaling function for the effective force acting on a single colloid located near the interface between two coexisting liquid phases of a binary liquid mixture close to its critical consolute point. This is the first study of critical Casimir forces emerging from the confinement of a fluctuating medium by at least one soft interface, instead by rigid walls only as studied previously. For this specific system, our semi-analytical calculation illustrates that knowledge of the colloid-induced, deformed shape of the interface allows one to accurately describe the effective interaction potential between the colloid and the interface. Moreover, our analysis demonstrates that the critical Casimir force involving a deformable interface is accurately described by a universal scaling function, the shape of which differs from that one for rigid walls.Comment: 19 pages, 11 figure

Exploring barriers to organ donation in the African American communities of California

There are a disproportionate number of African-Americans on transplant waiting lists across the country. The outcomes of a transplant are greatly improved when the donor and the recipient are from the same ethnic group. Sadly, the demand for cadaver organs in the African-American community exceeds the supply. Researchers in the past have sought to identify barriers to organ and tissue donation. To date, the studies have been conducted in the eastern and southern regions of the United States. This study examines whether the previously identified barriers are applicable in the African-American communities of California. A revised version of the Bone Marrow Donation Intention Tool was administered both in person and online. A t-test was used for analysis. The findings revealed statistically significant agreement/disagreement statements. These statements indicated that the barriers to organ donation from other areas of the United States were not representative of the respondents on the west coast

Young, UV-bright Stars Dominate Dust Heating in Star Forming Galaxies

In star forming galaxies, dust plays a significant role in shaping the ultraviolet (UV) through infrared (IR) spectrum. Dust attenuates the radiation from stars, and re-radiates the energy through equilibrium and non-equilibrium emission. Polycyclic aromatic hydrocarbons (PAH), graphite, and silicates contribute to different features in the spectral energy distribution; however, they are all highly opaque in the same spectral region - the UV. Compared to old stellar populations, young populations release a higher fraction of their total luminosity in the UV, making them a good source of the energetic UV photons that can power dust emission. However, given their relative abundance, the question of whether young or old stellar populations provide most of these photons that power the infrared emission is an interesting question. Using three samples of galaxies observed with the Spitzer Space Telescope and our dusty radiative transfer model, we find that young stellar populations (on the order of 100 million years old) dominate the dust heating in star forming galaxies, and old stellar populations (13 billion years old) generally contribute less than 20% of the far-IR luminosity.Comment: 12 pages, 8 figures, accepted to the Ap

Well-Posedness And Accuracy Of The Ensemble Kalman Filter In Discrete And Continuous Time

The ensemble Kalman filter (EnKF) is a method for combining a dynamical model with data in a sequential fashion. Despite its widespread use, there has been little analysis of its theoretical properties. Many of the algorithmic innovations associated with the filter, which are required to make a useable algorithm in practice, are derived in an ad hoc fashion. The aim of this paper is to initiate the development of a systematic analysis of the EnKF, in particular to do so in the small ensemble size limit. The perspective is to view the method as a state estimator, and not as an algorithm which approximates the true filtering distribution. The perturbed observation version of the algorithm is studied, without and with variance inflation. Without variance inflation well-posedness of the filter is established; with variance inflation accuracy of the filter, with resepct to the true signal underlying the data, is established. The algorithm is considered in discrete time, and also for a continuous time limit arising when observations are frequent and subject to large noise. The underlying dynamical model, and assumptions about it, is sufficiently general to include the Lorenz '63 and '96 models, together with the incompressible Navier-Stokes equation on a two-dimensional torus. The analysis is limited to the case of complete observation of the signal with additive white noise. Numerical results are presented for the Navier-Stokes equation on a two-dimensional torus for both complete and partial observations of the signal with additive white noise