Digital mammography, cancer screening: Factors important for image compression

The use of digital mammography for breast cancer screening poses several novel problems such as development of digital sensors, computer assisted diagnosis (CAD) methods for image noise suppression, enhancement, and pattern recognition, compression algorithms for image storage, transmission, and remote diagnosis. X-ray digital mammography using novel direct digital detection schemes or film digitizers results in large data sets and, therefore, image compression methods will play a significant role in the image processing and analysis by CAD techniques. In view of the extensive compression required, the relative merit of 'virtually lossless' versus lossy methods should be determined. A brief overview is presented here of the developments of digital sensors, CAD, and compression methods currently proposed and tested for mammography. The objective of the NCI/NASA Working Group on Digital Mammography is to stimulate the interest of the image processing and compression scientific community for this medical application and identify possible dual use technologies within the NASA centers

Effective Field Theory for Highly Ionized Plasmas

We examine the equilibrium properties of hot, dilute, non-relativistic plasmas. The partition function and density correlation functions of a classical plasma with several species are expressed in terms of a functional integral over electrostatic potential distributions. The leading order, field-theoretic tree approximation automatically includes the effects of Debye screening. Subleading, one-loop corrections are easily evaluated. The two-loop corrections, however, have ultraviolet divergences. These correspond to the short-distance, logarithmic divergence which is encountered in the spatial integral of the Boltzmann exponential when it is expanded to third order in the Coulomb potential. Such divergences do not appear in the underlying quantum theory --- they are rendered finite by quantum fluctuations. We show how such divergences may be removed and the correct finite theory obtained by introducing additional local interactions in the manner of modern effective quantum field theories. We obtain explicit results for density-density correlation functions through two-loop order and thermodynamic quantities through three-loop order. The induced couplings are shown to obey renormalization group equations, and these equations are used to characterize all leading logarithmic contributions in the theory. A linear combination of pressure and energy and number densities is shown to be described by a field-theoretic anomaly. The effective theory allows us to evaluate very easily the algebraic long-distance decay of density correlation functions.Comment: 194 pages, uses elsevier & epsf.sty; final corrections include

Confinement at Weak Coupling

The free energy of U(N) and SU(N) gauge theory was recently found to be of order N^0 to all orders of a perturbative expansion about a center-symmetric orbit of vanishing curvature. Here I consider extended models for which this expansion is perturbatively stable. The extreme case of an SU(2) gauge theory whose configuration space is restricted to center-symmetric orbits has recently been investigated on the lattice hep-lat/0509156. In extension of my talk, a discussion and possible interpretation of the observed finite temperature phase transition is given. The transfer matrix of constrained SU(N) lattice gauge theory is constructed for any finite temperature.Comment: 8 pages, no figures, updated talk given at LC2005 in Cairns, Australi

Is telomere length socially patterned? Evidence from the West of Scotland Twenty-07 study

Lower socioeconomic status (SES) is strongly associated with an increased risk of morbidity and premature mortality, but it is not known if the same is true for telomere length, a marker often used to assess biological ageing. The West of Scotland Twenty-07 Study was used to investigate this and consists of three cohorts aged approximately 35 (N = 775), 55 (N = 866) and 75 years (N = 544) at the time of telomere length measurement. Four sets of measurements of SES were investigated: those collected contemporaneously with telomere length assessment, educational markers, SES in childhood and SES over the preceding twenty years. We found mixed evidence for an association between SES and telomere length. In 35-year-olds, many of the education and childhood SES measures were associated with telomere length, i.e. those in poorer circumstances had shorter telomeres, as was intergenerational social mobility, but not accumulated disadvantage. A crude estimate showed that, at the same chronological age, social renters, for example, were nine years (biologically) older than home owners. No consistent associations were apparent in those aged 55 or 75. There is evidence of an association between SES and telomere length, but only in younger adults and most strongly using education and childhood SES measures. These results may reflect that childhood is a sensitive period for telomere attrition. The cohort differences are possibly the result of survival bias suppressing the SES-telomere association; cohort effects with regard different experiences of SES; or telomere possibly being a less effective marker of biological ageing at older ages

Socrates' Swan Song: Pythagorean Misinterpretations of Immortality in Plato's Phaedo

Unpublished manuscript exploring the philosophy in Plato's Phaedo, which describes Socrates’ final moments just before his execution as a swan song, and analyzing the philosophers' beliefs on death and immortality of the soul. This work is part of conference proceedings from the American Academy of Religion Annual Meeting, Boston, MA, December 5, 1987

The Sun and the Cave: Gulliver's Relationship to the Divine

Unpublished manuscript analyzing the religious philosophy of Gulliver in the novel Gulliver's Travels by Jonathan Swift. This work is part of conference proceedings from the American Academy of Religion Southwest Region conference held in, Irving, TX March 6-7, 1999

Joabin's Silence: Public and Private Life in Francis Bacon's New Atlantis (1626)

Unpublished manuscript exploring the role of Joabin in Francis Bacon's novel New Atlantis. This manuscript was part of the conference proceedings from the Academy of Jewish Philosophy, Hebrew Union College - Jewish Institute of Religion, Cincinnati, OH, June 9-10, 1991

University Scholars Day

This paper discusses research on Friedrich Nietzsche's affirmation of tragic morality

The peroxin PEX14 of Neurospora crassa is essential for the biogenesis of both glyoxysomes and Woronin bodies

In the filamentous fungus Neurospora crassa, glyoxysomes and Woronin bodies coexist in the same cell. Because several glyoxysomal matrix proteins and also HEX1, the dominant protein of Woronin bodies, possess typical peroxisomal targeting signals, the question arises as to how protein targeting to these distinct yet related types of microbodies is achieved. Here we analyzed the function of the Neurospora ortholog of PEX14, an essential component of the peroxisomal import machinery. PEX14 interacted with both targeting signal receptors and was localized to glyoxysomes but was virtually absent from Woronin bodies. Nonetheless, a pex14 Delta mutant not only failed to grow on fatty acids because of a defect in glyoxysomal beta-oxidation but also suffered from cytoplasmic bleeding, indicative of a defect in Woronin body-dependent septal pore plugging. Inspection of pex14 Delta mutant hyphae by fluorescence and electron microscopy indeed revealed the absence of Woronin bodies. When these cells were subjected to subcellular fractionation, HEX1 was completely mislocalized to the cytosol. Expression of GFP-HEX1 in wild-type mycelia caused the staining of Woronin bodies and also of glyoxysomes in a targeting signal-dependent manner. Our data support the view that Woronin bodies emerge from glyoxysomes through import of HEX1 and subsequent fission

Digital Mammography

In digital mammography, the processes of image acquisition, display, and storage are separated, which allows optimization of each. Radiation transmitted through the breast is absorbed by an electronic detector, the response of which is faithful over a wide range of intensities. Once this information is recorded, it can be displayed by using computer image-processing techniques to allow arbitrary settings of image brightness and contrast, without the need for further exposure to the patient. In this article, the current state of the art in technology for digital mammography and data from clinical trials that support the use of the technology will be reviewed. In addition, several potentially useful applications that are being developed with digital mammography will be described