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Biomedical subjects

Michael Gorman

Publications and source records attributed to Michael Gorman.

5 recordsLinked to original sources

Intellectual property rights, moral imagination, and access to life-enhancing drugs.

Although the idea of intellectual property (IP) rights--proprietary rights to what one invents, writes, paints, composes or creates--is firmly embedded in Western thinking, these rights are now being challenged across the globe in a number of areas. This paper will focus on one of those challenges: government-sanctioned copying of patented drugs without permission or license of the patent owner in the name of national security, in health emergencies, or life-threatening epidemics. After discussing standard rights-based and utilitarian arguments defending intellectual property we will present another model. IP is almost always a result of a long history of of scientific or technological development and numbers of networks of creativity, not the act of a single person or a group of people at one moment in time. Thus thinking about and evaluating IP requires a traditional model of IP. It follows that the owner of those rights has some obligations to share that information or its outcomes. If that conclusion is applied to the distribution of antiretroviral drugs, what pharmaceutical companies are ethically required to do to increase access to these medicines in the developing world will have to be reanalyzed from a more systemic perspective.

Anti-HIV Agents↗

Spiral dynamics of pulsating methane-oxygen flames on a circular burner.

A premixed flame stabilized on a circular porous plug burner produces a uniform, steady luminous flame front. Throughout much of the parameter range hydrocarbon-oxygen mixtures form spiral-shaped fronts. In methane-oxygen flames at low pressure, the flame exhibits a sequence of states as a control parameter is decreased. These states include periodic rotation of a spiral front; precession of the spiral front in a direction opposite to its rotation, corresponding to doubly periodic petals-out meandering; and nonperiodic states with intermittent jumps associated with linear excursions of the tip, which occur after the spiral front has reached the boundary of the circular burner. We use Karhunen-Loeve (KL) analysis to find the coefficients of the dominant KL spatial eigenfunctions. Their phase space portraits and power spectra provide a description of the dynamics as flow rates are reduced and the system destabilizes. We discuss how these experimental results relate to previous theoretical studies that assume Euclidean symmetry for the experimental configuration.

Journal Article↗

Modal decomposition of hopping states in cellular flames.

We use Karhunen-Loeve (KL) decomposition of video images from an experiment to analyze a spatiotemporal dynamic state, unique to cellular flames, referred to as a "hopping state." Ordered states of cellular flames on a circular burner consist of one or two concentric rings of luminous cells. The hopping states correspond to the motions of individual cells in a ring sequentially executing abrupt changes in their angular position, while the other cells in the ring remain symmetric and at rest. KL decomposition separates the spatial and temporal characteristics of the hopping motion. The underlying symmetries of the experiment allow us to deduce a set of normal form equations that describe the formation of these states. We find that they result from secondary bifurcations connecting two primary branches of traveling waves. The solutions corresponding to hopping states exist as mixed-mode solutions away from the secondary bifurcations. (c) 1999 American Institute of Physics.

Journal Article↗

Cellular pattern formation in circular domains.

An analysis of stationary and nonstationary cellular patterns observed in premixed flames on a circular, porous plug burner is presented. A phenomenological model is introduced, that exhibits patterns similar to the experimental states. The primary modes of the model are combinations of Fourier-Bessel functions, whose radial parts have neighboring zeros. This observation explains several features of patterns, such as the existence of concentric rings of cells and the weak coupling between rings. Properties of rotating rings of cells, including the existence of modulated rotations and heteroclinic cycles can be deduced using mode coupling. For nonstationary patterns, the modal decomposition of experimental data can be carried out using the Karhunen-Loeve (KL) analysis. Experimental states are used to demonstrate the possibility of using KL analysis to differentiate between uniform and nonuniform rotations. The methodology can be extended to study more complicated nonstationary patterns. In particular, it is shown how the complexity of "hopping states" can be unraveled through the analysis. (c) 1997 American Institute of Physics.

Journal Article↗