815 research outputs found
Theoretical studies in support of the 3M-vapor transport (PVTOS-) experiments
Results are reported for a preliminary theoretical study of the coupled mass-, momentum-, and heat-transfer conditions expected within small ampoules used to grow oriented organic solid (OS-) films, by physical vapor transport (PVT) in microgravity environments. It is show that previous studies made restrictive assumptions (e.g., smallness of delta T/T, equality of molecular diffusivities) not valid under PVTOS conditions, whereas the important phenomena of sidewall gas creep, Soret transport of the organic vapor, and large vapor phase supersaturations associated with the large prevailing temperature gradients were not previously considered. Rational estimates are made of the molecular transport properties relevant to copper-phthalocyanine monomeric vapor in a gas mixture containing H2(g) and Xe(g). Efficient numerical methods have been developed and are outlined/illustrated here to making steady axisymmetric gas flow calculations within such ampoules, allowing for realistic realistic delta T/T(sub)w-values, and even corrections to Navier-Stokes-Fourier 'closure' for the governing continuum differential equations. High priority follow-on studies are outlined based on these new results
Self-Deception and Cosmic Disorder in the Book of Job
The book of Job fundamentally involves the confrontation (or lack thereof) with the apparent upending of the universe's entire moral order. This paper will employ the concept of self-deception as put forth in twentieth-century existential philosophy to explain the behavior of Job's three ‘friends' - Eliphaz, Bildad, and Zophar - in the face of this apparent moral chaos. I shall also access a number of "trauma studies" based Biblical interpretations to expand our understanding of this theme
Measuring Strong and Weak Phases in Time-Independent B Decays
Flavor SU(3) symmetry implies certain relations among -decay amplitudes to
, and final states, when annihilation-like
diagrams are neglected. Using three triangle relations, we show how to measure
the weak CKM phases and using time-independent rate
measurements only. In addition, one obtains all the strong final-state phases
and the magnitudes of individual terms describing tree (spectator),
color-suppressed and penguin diagrams. Many independent measurements of these
quantities can be made with this method, which helps to eliminate possible
discrete ambiguities and to estimate the size of SU(3)-breaking effects.Comment: 2 figures available from the authors upon request, 12
pages,UdeM-LPN-TH-94-19
Model of Transcriptional Activation by MarA in Escherichia coli
We have developed a mathematical model of transcriptional activation by MarA
in Escherichia coli, and used the model to analyze measurements of
MarA-dependent activity of the marRAB, sodA, and micF promoters in mar-rob-
cells. The model rationalizes an unexpected poor correlation between the
mid-point of in vivo promoter activity profiles and in vitro equilibrium
constants for MarA binding to promoter sequences. Analysis of the promoter
activity data using the model yielded the following predictions regarding
activation mechanisms: (1) MarA activation of the marRAB, sodA, and micF
promoters involves a net acceleration of the kinetics of transitions after RNA
polymerase binding, up to and including promoter escape and message elongation;
(2) RNA polymerase binds to these promoters with nearly unit occupancy in the
absence of MarA, making recruitment of polymerase an insignificant factor in
activation of these promoters; and (3) instead of recruitment, activation of
the micF promoter might involve a repulsion of polymerase combined with a large
acceleration of the kinetics of polymerase activity. These predictions are
consistent with published chromatin immunoprecipitation assays of interactions
between polymerase and the E. coli chromosome. A lack of recruitment in
transcriptional activation represents an exception to the textbook description
of activation of bacterial sigma-70 promoters. However, use of accelerated
polymerase kinetics instead of recruitment might confer a competitive advantage
to E. coli by decreasing latency in gene regulation.Comment: 30 pages, 2 figure
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Seeking common ground : a history of labor and Blue Cross
In recent years, voluntary health insurance costs have become a major source of friction in labor-management negotiations. What was once a "fringe" has led to job actions, strikes, and intensive bargaining. We examine the history of labor's participation in New York Blue Cross from the 1930s to the recent past and show that labor's participation in the plan was crucial to Blue Cross's success in the plan's early decades. By the late 1950s, serious tensions developed over rate increases and the participation of labor in Blue Cross governance. Ultimately, the issue was one of the control over what was provided by the plans and who would pay for the costs of care. We posit that labor was never able to achieve an important role in the control of the third-party payer, and in the antilabor environment of the 1980s this proved detrimental to labor's interests
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