Access path selection in a relational database management system

ABSTRACT: In a high level query and data manipulation language such as SQL, requests are stated non-procedurally, without reference to access paths. This paper describes how System R chooses access paths for both simple (single relation) and complex queries (such as joins), given a user specification of desired data as a boolean expression of predicates. System R is an experimental database management system developed to carry out research on the relational model of data. System R was designed and built by members of the IBM San Jose Research'Laboratory. 1

Episcleral plaque brachytherapy using ′BARC I-125 Ocu-Prosta seeds′ in the treatment of intraocular tumors: A single-institution experience in India

Context: To analyze the results of episcleral plaque brachytherapy using indigenous Bhabha Atomic Research Centre (BARC) Iodine-125 Ocu-Prosta seeds for the management of intraocular tumors from a single institute. AIM: To report our initial experience and learning curve on the use of ′BARC I-125 Ocu-Prosta seeds′ for the management of intraocular tumors such as choroidal melanomas, retinoblastomas and vasoproliferative tumors (VPT). Materials and Methods: We retrospectively reviewed 13 eyes of 13 patients who underwent ophthalmic brachytherapy between May 2008 to March 2012. Nine cases had choroidal melanomas; three had retinoblastomas while one case had VPT. Results: For choroidal melanomas the average apical diameter before brachytherapy was 7.6 mm and average largest basal diameter was 12.1 mm, respectively, which reduced to 4.2 mm and 7.7 mm after the procedure at an average follow-up of 24 months (range 10-43 months). Retinoblastoma and VPT also showed good regression after brachytherapy. Conclusion: Plaque radiotherapy using 125 I seeds can be performed under peribulbar anesthesia and provides a viable option for the management of intraocular cancer with minimal invasiveness and surgical complications. Patients in our studies experienced excellent local tumor control. With the availability of indigenous ′BARC I-125 Ocu-Prosta seeds′ locally, cost effective ophthalmic brachytherapy can be performed in India