Holography utilizing surface plasmon resonances

A holographic recording medium with a substrate which has a diffraction grating composed of a number of spaced line ridges on the surface is discussed. The first layer consists of a metal with a plasma wavelength shorter than that of the selected light source. A second layer, or coating, on top of the first layer consists of a thin film of photosensitive emulsion. A diagram of the device is provided. The principles of operation are explained

A study of space contamination by means of the surface plasma resonance effect in grating diffraction

Surface plasma resonance effect in diffraction gratings and relation of effect to space contamination by spacecraft instrument

The Early Formation, Evolution and Age of the Neutron-Capture Elements in the Early Galaxy

Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. These observations demonstrate that the earliest generations of stars in the Galaxy, responsible for neutron-capture synthesis and the progenitors of the halo stars, were rapidly evolving. Abundance comparisons among several halo stars show that the heaviest neutron-capture elements (including Ba and heavier) are consistent with a scaled solar system r-process abundance distribution, while the lighter such elements do not conform to the solar pattern. These comparisons suggest two r-process sites or at least two different sets of astrophysical conditions. The large star-to-star scatter observed in the neutron-capture/iron ratios at low metallicities -- which disappears with increasing [Fe/H] -- suggests an early, chemically unmixed and inhomogeneous Galaxy. The stellar abundances indicate a change from the r-process to the slow neutron capture (i.e., s-) process at higher metallicities in the Galaxy. The detection of thorium in halo and globular cluster stars offers a promising, independent age-dating technique that can put lower limits on the age of the Galaxy.Comment: 6 pages, 3 figures; To appear in the proceedings of the 20th Texas Symposium on Relativistic Astrophysics, J. C. Wheeler & H. Martel (eds.

Nuclear Chronometers

Observations of metal-poor Galactic halo stars indicate that the abundance pattern of the (heaviest) neutron-capture elements is consistent with the scaled solar system r-process abundances. Utilizing the radioactive (r-process) element thorium, age determinations have been made for several of these same stars, placing constraints on both Galactic and cosmological age estimates.Comment: 6 pages, 2 figures. To appear in the Proceedings of ``Cosmic Evolution'

Galactic Cosmochronometry from Radioactive Elements in the Spectra of Very Old Metal-Poor Stars

In a short review of neutron-capture elemental abundances in Galactic halo stars, emphasis is placed on the use of these elements to estimate the age of the Galactic halo. Two prominent characteristics of neutron-capture elements in halo stars are their large star-to-star scatter in the overall abundance level with respect to lighter elements, and the dominance of r-process abundance patterns at lowest stellar metallicities. The r-process abundance signature potentially allows the direct determination of the age of the earliest Galactic halo nucleosynthesis events, but further developments in r-process theory, high resolution spectroscopy of very metal-poor stars, and in basic atomic data are needed to narrow the uncertainties in age estimates. Attention is brought to the importance of accurate transition probabilities in neutron-capture element cosmochronometry. Recent progress in the transition probabilities of rare earth elements is discussed, along with suggestions for future work on other species.Comment: 19 pages, 5 figures; To appear in Physica Script

Neutron-Capture Element Trends in the Halo

In a brief review of abundances neutron-capture elements (Z > ~30) in metal-poor halo stars, attention is called to their star-to-star scatter, the dominance of r-process synthesis at lowest metallicities, the puzzle of the lighter members of this element group, and the possibility of a better r-/s-process discriminant.Comment: 6 pages, 2 figures. To appear in the Proceedings of ``Cosmic Evolution'

The lick

'The Rise of Women Artists' charts the progress made by female artists from the 16th century up to the present day. Judith Cowan’s sculpture, The Lick, 1999, is shown alongside recent and contemporary artists such as Louise Bourgeois, Paula Rego, Hermione Wiltshire, Christine Borland, Helen Chadwick, Louise Bourgeois and historical artists such as Angelica Kauffmann, Marianne Stokes and Laura Knight. Curated by Dr Laura MacCulloch and drawn from the Walker Gallery’s collection. The exhibition asks questions such as, does the gender of an artist matter? What is the effect of labeling? What is the significance of the decorative and fine arts co-existing? Cowan’s gesture of impermanence is embodied in the roll of fabric held by the wax cast of her tongue and mouth, like a false moustache. Seen in a perspex box large enough for the whole head, the stranded tongue sticking out is a gesture of the living against death and is the last work seen on leaving the exhibition

An investigation into factors affecting the lactobacillus casei assay of folate in serum

Imperial Users onl

Who are these people/Melancholia exists. [shown as part of Rugby's 2010 anniversary show].

In their 2010 anniversary show, Rugby Art Gallery and Museum profiled two of Judith Cowan's sculptures ‘Who are these people?’ 2005, and ‘Melancholia exists’, 2003. with several related recent work, (including Cowan's Memory of a place in Rome). Judith Cowan’s fascination with the filmic scene is evident within both the sculptures and the drawing. The audience sees things, then, the roles flip as they discover they are in the scene with other people passing and interacting with the work. Who are these people? 2005, uses a wooden model to place the viewer in a theatre-like set before, after and literally behind the scene. Its miniature frame holds an amber, translucent panel that creates a window or film frame. This integrates a constant changeability to whatever the viewer sees through the aperture. ‘Melancholia exists’, 2003, shows the living past tries to cling to the present. The old white chest of drawers support a plaster cast of the vestiges of space between a body and its arms. Its amber, perspex cover, makes it appear almost living from the sides, whilst the opening at the top reveals a white in-between space like a hollowed out rock. Window sash-cords spill out of drawers, some opening to occupy the space of the viewer, so they begin to occupy an inter-space between theatrical prop and art object