1,094 research outputs found
The Social Value of Using Biodiversity in New Pharmaceutical Product Research
Biologists and conservation advocates have expressed grave concern over perceived threats to biological diversity. "Biodiversity prospecting"—the search among naturally occurring organisms for new products of agricultural, industrial, and, particularly, pharmaceutical value—has been advanced as both a mechanism and a motive for conserving biological diversity. Economists and others have attempted to estimate the value of biodiversity for use in new pharmaceutical project research. Most of these existing approaches are incomplete, however, as they have not yet considered full social welfare, i.e., both consumer surplus and profit. This paper addresses social welfare by calibrating a model of competition between differentiated products with data from the pharmaceutical industry. We find that the magnitude of losses from even catastrophic declines in biodiversity are negligible in comparison to the value of world production. While social values of biodiversity prospecting might motivate habitat conservation in some areas, these values are likely to be small relative to land value in other uses in even some of the more biologically rich regions of the world.
Aerospace engineering educational program
The principle goal of the educational component of NASA CORE is the creation of aerospace engineering options in the mechanical engineering program at both the undergraduate and graduate levels. To accomplish this goal, a concerted effort during the past year has resulted in detailed plans for the initiation of aerospace options in both the BSME and MSME programs in the fall of 1993. All proposed new courses and the BSME aerospace option curriculum must undergo a lengthy approval process involving two cirriculum oversight committees (School of Engineering and University level) and three levels of general faculty approval. Assuming approval is obtained from all levels, the options will officially take effect in Fall '93. In anticipation of this, certain courses in the proposed curriculum are being offered during the current academic year under special topics headings so that current junior level students may graduate in May '94 under the BSME aerospace option. The proposed undergraduate aerospace option curriculum (along with the regular mechanical engineering curriculum for reference) is attached at the end of this report, and course outlines for the new courses are included in the appendix
Multicriteria VMAT optimization
Purpose: To make the planning of volumetric modulated arc therapy (VMAT)
faster and to explore the tradeoffs between planning objectives and delivery
efficiency.
Methods: A convex multicriteria dose optimization problem is solved for an
angular grid of 180 equi-spaced beams. This allows the planner to navigate the
ideal dose distribution Pareto surface and select a plan of desired target
coverage versus organ at risk sparing. The selected plan is then made VMAT
deliverable by a fluence map merging and sequencing algorithm, which combines
neighboring fluence maps based on a similarity score and then delivers the
merged maps together, simplifying delivery. Successive merges are made as long
as the dose distribution quality is maintained. The complete algorithm is
called VMERGE.
Results: VMERGE is applied to three cases: a prostate, a pancreas, and a
brain. In each case, the selected Pareto-optimal plan is matched almost exactly
with the VMAT merging routine, resulting in a high quality plan delivered with
a single arc in less than five minutes on average.
VMERGE offers significant improvements over existing VMAT algorithms. The
first is the multicriteria planning aspect, which greatly speeds up planning
time and allows the user to select the plan which represents the most desirable
compromise between target coverage and organ at risk sparing. The second is the
user-chosen epsilon-optimality guarantee of the final VMAT plan. Finally, the
user can explore the tradeoff between delivery time and plan quality, which is
a fundamental aspect of VMAT that cannot be easily investigated with current
commercial planning systems
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