The geography of UK international trade.

This paper examines how the geography of UK international trade has changed since the UK’s accession to the European Economic Community using a newly constructed data set that gives a detailed breakdown of the UK’s imports and exports by both port of entry and exit and commodity. Our results suggest that between 1970 and 1992 overall imports and exports re-orientated in favour of ports located nearer to the continent. The vast majority of individual commodities also saw a similar re-orientation.

On the Formation of Multiple-Shells Around Asymptotic Giant Branch Stars

Two types of models for the formation of semi-periodic concentric multiple shells (M-shells) around asymptotic giant branch (AGB) stars and in planetary nebulae are compared against observations. Models that attribute the M-shells to processes in an extended wind acceleration zone around AGB stars result in an optically thick acceleration zone, which reduces the acceleration efficiency in outer parts of the extended acceleration zone. This makes such models an unlikely explanation for the formation of M-shells. Models which attribute the M-shell to semi-periodic variation in one or more stellar properties are most compatible with observations. The only stellar variation models on time scales of 50-1500 years that have been suggested are based on an assumed solar-like magnetic cycle. Although ad-hoc, the magnetic cycle assumption fits naturally into the increasingly popular view that magnetic activity plays a role in shaping the wind from upper AGB stars.Comment: 8 pages, Submitted to Ap

Advances in single-pixel imaging toward biological applications

2014 Summer.In this work, we discuss two new methods for single-pixel imaging. First, we leverage advances in laser metrology and frequency synthesis to measure small shifts in the center frequency of an optical pulse. Pulses acquire such shifts when probing a transient optical susceptibility, as in impulsive stimulated Raman scattering, which we use to demonstrate the technique. We analyze the limits of this technique with regard to fundamental noise, and predict detection sensitivity in these limiting cases. We then present work on imaging in two dimensions, both x-y and x-z, using single element detectors. We accomplish this by multiplexing spatial frequency projections in time, allowing rapid two dimensional imaging without an imaging detector. As we eliminate the imaging detector, the sensitivity to scattering is dramatically decreased, allowing the method to be used deep in scattering tissue. Results are shown for several geometries and experimental configurations, demonstrating imaging capabilities across a variety of sample types, including fluorescent and biological samples

Nearby Red Dwarfs and Their Dance Partners: Characterizing More Than 2000 Single and Multiple M Dwarfs Near the Sun

This dissertation presents the results of a study to (1) determine the census of the nearby southern M dwarf stellar population via three types of distances and (2) determine the multiplicity rate of nearby M dwarfs using two different search methodologies. The first part of this work reports three types of distance calculations (photographic, photometric, and trigonometric) for 1748 southern M dwarfs. Distances were estimated for 500 red dwarfs using photographic plate BRI magnitudes from SuperCOSMOS, while estimates were made for 667 stars using CCD VRI magnitudes. Both BRI and VRI were combined with 2MASS infrared JHK magnitudes. Distances for an additional 581 red dwarfs were derived from trigonometric parallaxes, 124 of which were measured for the first time during this work. For the second portion of this thesis, an all-sky sample of 1122 M dwarfs, known via trigonometric parallaxes to lie within 25 pc of the Sun, was surveyed for stellar companions at separations of 2 to 600 . I-band images using primarily the CTIO/SMARTS 0.9m and the Lowell 42in telescopes were obtained in order to search these systems for companions at separations of 2 to 180 . A complementary reconnaissance of wider companions to 600 was also done via blinking SuperCOSMOS BRI images. We find a stellar multiplicity fraction of 27.4 $\pm$ 1.3% for M dwarfs. Using this new gauge of M dwarf multiplicity near the end of the stellar main sequence, we calculate a multiplicity fraction of 30.1% for stellar systems of all types, implying that most systems are single. We find a peak in the separation distribution of the companions at 26 AU, i.e., distances on the scale of our Solar System, with a weak trend of smaller projected separations for lower mass primaries. A hint that M dwarf multiplicity may be a function of age/composition was revealed, with faster moving (and generally older) systems being multiple slightly less often. We calculate that at least 16% of M dwarf mass is made up of the stellar companions of multiple systems. Finally, we show that the mass function for M dwarfs increases to the end of the main sequence

Tissue holder for experimental and Demonstration Surgery

Development of device for holding anatomical tissues during operations is discussed. Device consists of plastic dish with hemispherical recess in center to hold excised eyes. Low vacuum applied to underside of recess insures holding of part