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D Riordan

Publications and source records attributed to D Riordan.

6 recordsLinked to original sources
PubMed1991

Ecological applications using a novel expert system shell.

Much of the information used by ecologists in modelling and decision making is imprecise. The imprecision arises both from data that are inexact or incomplete and from the use of ecological principles that are sometimes less than fully reliable and may be conflicting. Nevertheless, expert ecologists are able to construct usable models and make decisions that are used to manage and control ecological resources. This paper describes a unique expert system shell, developed in conjunction with user ecologists, which incorporates features enabling ecologists to represent knowledge and uncertainty in their expert systems in a way that is natural and appropriate. The reasoning mechanism was similarly developed in conjunction with user ecologists. It produces solutions to a class of expert level problems along with explanatory mechanisms and an appropriate analysis of the reasoning process. Three expert systems have been constructed by ecologists using this expert system shell. This enabled the shell designers to evaluate features for inclusion in the shell. The successful use of the shell by the ecologists has shown that significant economies arise when expert system shell design is tailored to use by a specific class of experts, in this case ecologists.

Ecology↗
PubMed1990

Variant Philadelphia translocations in chronic myeloid leukemia: correlation with cancer breakpoints, fragile sites and oncogenes.

Four cases of variant Philadelphia (Ph1) translocations were found in 72 patients (5.5%) with Ph1-positive chronic myeloid leukemia (CML). One previously unreported case was a simple variant translocation, namely, 46,XY,t(11;17)(q13;p13),t(17;22)(q25;q22); 46,XY,t(1;21)(q32;q11),t(11;17)(q13;p13), t(17;22)(q25;q11). Complex variant translocations were observed in three cases, namely, 46,XY,t(5;9;22)(q31;q34;q11),46,XX,t(8;9;22) (q22;q34;q11) and 46,XX,t(9;15;22) (q34;q15;q11). The chromosomal breakpoints in the cases of variant Ph1 translocations were the following: 1q32, 5q31, 8q22, 11q13, 15q15, 17p13, 17q25 and 21q11. Eight of the eight (100%) breakpoints were located in Giemsa-negative bands. Furthermore, seven of the eight (87%) variant Ph1 breakpoints correspond to the breakpoints present in consistent cancer arrangements. Three of the eight (38%) correspond to fragile sites and four of the eight (50%) correspond to oncogenes.

Genetic Variation↗
PubMed1988

Chromosome analysis in chorionic villi samples from the first trimester elective terminations.

Chorionic villi sampling (CVS) has become a first trimester alternative to amniocentesis for prenatal diagnosis. The cytogenetic findings in 150 experimental samples are presented. The ages of the mothers ranged from 12 to 35 years, but the majority of them were 18 and 19 years of age. Various parameters of culturing and processing the samples in order to improve the method, were investigated. Short term incubation for 48 h was the method routinely employed in processing the biopsies for cytogenetic analysis. In the first series of 100 cases one mosaic case (46,XX/45,X), one Robertsonian translocation (13;14), one marker chromosome and one fragment were found. The foetal tissues were not analysed for chromosomes. In the second series of 50 samples, one case of mosaicism was found in the chorionic villi (46,XX/47,XX, 18q-), but this abnormality was absent in the foetal tissue. One variant inv(9) was observed in the foetal tissue as well as in the chorionic villi. In all other cases the karyotypes from the chorionic villi samples matched those of the corresponding foetal samples. There was no maternal contamination in this series of 50 samples. The discrepancies in the cytogenetic results from other investigators are discussed.

Chorionic Villi↗
PubMed1987

Wrist arthroplasty: a retrospective study.

A retrospective study was conducted to evaluate the long-term effectiveness of wrist arthroplasties in patients with various arthritic conditions. A total of 39 wrist arthroplasties were performed in 29 patients (average age, 52.5 years) by the orthopedic staff at Tulane University School of Medicine. Rheumatoid arthritis was the major presenting diagnosis in 84.6% of these operative cases and pain was the most common indication for surgery (79.5%). Postoperative relief of pain was reported in all of the cases reviewed, with an average follow up period of 51.2 months (range, 12 to 118 months). A group of 15 patients who were examined clinically had an average grip strength of 19.2 lb (range, 6 lb to 45 lb). Pinch measurements averaged 1.9 lb and arc of motion averaged 59.5 degrees (range, 20 degrees to 100 degrees) for these patients. Postoperative complications included dislocation (3 cases), fracture of the prosthesis (2 cases), and infection (2 cases). No complications were observed in 32 (82.1%) of the 39 cases reviewed. This retrospective study revealed that at an average follow up period of 51.2 months, pain relief was excellent and patient acceptance was good, with 94.9% of the wrists having been improved by the procedure. The majority (82.1%) of the cases were free of complication. It is concluded from this study that wrist arthroplasty is a viable alternative to wrist arthrodesis.

Adult↗