A binary image can be exactly reconst cted if we know the centers and radii of its maximal blocks of 1's, since the set of I's is the union of these maximal blocks. This representa-tion is called the medial axis transformation (MAT) [1], since

Ballistic missiles and anti-satellite (ASAT) weapons operate using sim-ilar technological means but not with the same level of technology or en-gineering maturity. ASATs require more sophisticated systems engineering and integration requirements to adapt to the challenges posed by an ASAT intercept. The main difficulties arise from the requirements for detection in space and the high closing velocities needed to execute an ASAT inter-cept [1]. These difficulties have been underestimated after the recent Chinese ASAT test by those who have suggested that other nations could in the near-future master this technology gap and convert their primitive ballistic missile capabilities into an effective ASAT weapons capability. This report examines whether Iran could use its modest missile capability to project a viable ASAT threat to US Low-Earth Orbit (LEO) satellites. The study suggests that, even if Iran has an Intermediate Range Ballistic Missile (IRBM), it would not be easily able to leap-frog the technology gap

was presented at the AEA 1999 New York Meetings, and at the Winter Camp in International Finance, organized by the Center for International Economics (University of Maryland) and the Faculty of Economics (Universidad de los Andes, Bogota, Colombia) in Cartagena, Colombia, January 7-11, 1999. I would like

lators (ICDs) have become the stan-dard treatment for patients at high risk of sudden death due to ventricu-lar arrhythmias. Because implanta-tion of an ICD is not a cure, the risk of recurrence of arrhythmia is not reduced, and frequent sequential ICD shocks can cause patients marked discomfort.1 This discomfort accounts for decreased acceptance of the device and a decreased quality of life among patients.2 Although phar-macological treatment of ventricular tachycardia can help reduce recur-rences of sustained arrhythmia, antiarrhythmic drugs have been associated with low efficacy, proar-rhythmic actions, and frequent toxic effects or long-term adverse effects.3 These problems associated with pharmacological therapies have prompted a search for alternative approaches to decrease recurrence of potentially lethal ventricular dys-rhythmias. One of these approaches involves ablation of the arrhythmo-genic myocardial focus. With radiofrequency ablation, alternating current is delivered in low voltage (typically 40 V) for 30 to 60 seconds to cause controlled ther-mal injury of the contacted myocar-dial tissue. This current is delivered between a catheter tip and an indif-ferent electrode (ground patch). The lesion created is discrete and its loca-tion is precisely defined, with minimal risk of damage to adjacent structures. Irreversible injury occurs when the myocardial tissue reaches a tempera-ture of 48ºC to 50ºC.4 Radiofrequency ablation has rev-olutionized therapy of most forms of supraventricular tachycardia and ventricular tachycardia in patients without structural heart disease by providing arrhythmia cure in almost 90 % of cases.5 These types of tachy-cardia are due to an arrhythmia focus that occurs in a fixed location, pro-viding a precise target and making the tachycardia more amenable to treatment by ablation. Most cases of ventricular tachycardia in patients without heart disease originate from

CONTRACT 300-79-0519

largest annual physics meeting in the country, will take place from

between manual and automated systems. A. selected bibliography and a list,of Baltimore,information centersNand services are attached. (Author/HP)

The concept for this assessment originated with the Board of the Maryland Environmental Trust, Maryland’s premier quasi-governmental agency responsible for garnering and holding easement donations. Financial support for the assessment was provided by a grant administered through the Maryland Center

The center-region components of the Maryland cyclotron were designed with the maximum degree of flexibility permitted by ' geometrical restraints. Theoretical studies of initial orbits were based on electric field data, obtained with a filly automated electrolytic tank system. The desired

is comprised of Maryland’s public institutions that collaborate under memoranda of