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G Trotter

Publications and source records attributed to G Trotter.

At least 19 recordsLinked to original sources

New insight into enhanced superconductivity in metals near the metal-insulator transition.

We have studied the transport properties of disordered WSi films near the metal/insulator transition (MIT) and we have also reviewed the data for several other disordered materials near their MIT. In all cases, we found the presence of enhanced superconductivity. We constructed a superconductivity "phase diagram" (i.e., T(c) versus sigma) for each system, which reveals a striking correlation: In all cases, T(c) values are significantly enhanced only for samples whose conductivities lie within a narrow range on the metallic side of, and moderately near, the MIT. We present a heuristic model to explain this phenomenon.

Journal Article↗

Pragmatism, bioethics and the grand American social experiment.

There is tension in bioethics between two strains of pragmatism. The most prominent strain, following John Dewey, proposes a content-rich ethos of controlled, collective moral inquiry. A second strain, descending from Charles Peirce and Josiah Royce, favors an open-ended approach where diverging moral communities evolve without extensive inter-communal oversight. This essay defends the second strain. The Deweyan approach, I argue, exhibits a problematic quasi-foundationalist character insofar as it canonizes a dubious constellation of "liberal" political values and seeks to establish these values by interposing a consensus of moral experts where genuine inter-communal dialogue, and compromise, would be more fruitful. I hold that the alternative approach of Peirce and Royce is preferable, and truer to the fundamental commitments of classical American pragmatism. Recognizing the epistemic fallibility of various content-rich moral-political formulations, Peirce and Royce hope to cultivate and sustain moral inquiry by allowing each moral community (1) to generate and test its own moral system (as long as it does so peaceably) and (2) to freely make or refuse to make collaborative arrangements with other moral communities. This approach is illustrated in a brief discussion of the Oregon Medical Experiment.

Bioethics↗

Mantle planning: report of the Australasian Radiation Oncology Lymphoma Group film survey and consensus guidelines.

The purpose of the present paper was to measure the variation in mantle planning in Australia and New Zealand. A chest X-ray (CXR) of a patient in the supine position with a neck node marked by wire was sent to every radiation oncologist in Australia and New Zealand. They were to mark on the CXR the lung blocks that they would use to treat this patient, assuming that the patient had stage IA Hodgkin's disease. These marks were compared with a small sample of radiologists who were asked to define the mediastinum on the same CXR. Radiation oncologists were also asked to complete a short questionnaire about other modifications to their treatment fields and their experience with this technique. One hundred and six films were sent out and 44 radiation oncologists replied. There was a maximum variation in the placement of their lung blocks of 6 cm. Half of the lung blocks were within a 2-cm range. One respondent said they would not use a mantle field to treat this patient. Mediastinal coverage was inadequate in at least 50% of cases. There was a very large variation in mantle field planning practices within Australia and New Zealand. For this reason Australasian Radiation Oncology Lymphoma Group has produced consensus guidelines for mantle block design. These are appended to the present paper.

Australia↗

Phase II multicenter study of brief single-agent methotrexate followed by irradiation in primary CNS lymphoma.

PURPOSE: To assess, in a multi-institutional setting, the impact on relapse, survival, and toxicity of adding two cycles of intravenous methotrexate to cranial irradiation for immunocompetent patients with primary CNS lymphoma. PATIENTS AND METHODS: Forty-six patients with a median age of 58 years and Eastern Cooperative Oncology Group performance status 0 to 3 were entered onto this phase II study. The protocol consisted of methotrexate 1 g/m(2) on days 1 and 8 followed by cranial irradiation on day 15. A whole-brain dose of 45 Gy was followed by a boost of 5.4 Gy. Intrathecal chemotherapy and spinal irradiation were given only to patients for whom cytologic examination of CSF was positive for CNS lymphoma. The median follow-up time was 36 months, with a minimum potential follow-up of 12 months. RESULTS: Median survival was 33 months, with 2-year probability of survival 62% +/- 15% (95% confidence interval). Twenty patients have relapsed. The predominant site of relapse was the brain. Neither performance status nor age was found to influence survival. Six patients developed a dementing illness at a median of 16 months after treatment, and three of these died as a consequence. CONCLUSION: A brief course of intravenous methotrexate before cranial irradiation is associated with 2-year and median survival rates superior to those reported for radiotherapy alone and similar to more intensive combined-modality regimens. Neurotoxicity remains an important competing risk for these patients.

Adult↗

Culture, ritual, and errors of repudiation: some implications for the assessment of alternative medical traditions.

In this article, sources of error that are likely involved when alternative medical traditions are assessed from the standpoint of orthodox biomedicine are discussed. These sources include (1) biomedicine's implicit reductive materialism (manifested in its negative orientation toward placebo effects), (2) a related bias against ritual, and (3) cultural barriers to the construction of externally valid protocols. To overcome these biases, investigators must attend to ritualistic elements in alternative treatments and should recruit patients from appropriate cultural groups. Collaborative research may be the key. Benefits of collaborative research include (1) increased mutual respect and integration between culturally distinct groups and practices, (2) increased understanding and use of sophisticated techniques of empirical analysis among practitioners from the alternative traditions, (3) increased appropriation of the therapeutic benefits of ritual, and (4) enhanced overall benefit for patients of all cultural backgrounds.

Complementary Therapies↗

Radiotherapy for early infradiaphragmatic Hodgkin's disease: the Australasian experience.

PURPOSE: To review the Australasian results of Stage I and IIA Infradiaphragmatic Hodgkin's Disease (IHD) treated solely by irradiation. METHODS AND MATERIALS: Eligible patients had IHD only and were treated by irradiation with curative intent over the period of 1969 to 1988. Ten radiation oncology centres from within Australia and New Zealand were surveyed for patient, tumour and treatment variables. Disease free rates, survival and complications were analysed. RESULTS: 106 patients with IHD were studied. The average potential follow up was 9.4 years. The male to female ratio was 3.3:1. The median age was 37.5 years. Histological subgroups were as follows; lymphocyte predominant 43%, mixed cellularity 21%, lymphocyte depleted 5%, nodular sclerosing 27% and unclassifiable 4%. Fifty nine patients had laparotomy of which 22 (37%) were positive for tumour. Nine laparotomies were performed for diagnosis and the remainder for staging. One patient was up-staged by laparotomy and three were down-staged. Sixty-eight patients presented with inguinal disease alone, five with abdominal disease alone, 19 with two sites of involvement and 12 with inguinal, pelvic and abdominal disease. In two patients the site was unknown. There was no correlation between site of involvement, age, sex or histological subtype. Forty seven cases were clinically staged (CS) as follows: CS IA-23, CS IIA-24. The other 59 were pathologically staged (PS) as follows: PS IA-37, PS IB-1, PS IIA-21. Treatment consisted of involved field alone (16), inverted Y (68), inverted Y and spleen (13), para-aortic irradiation only (3), or total nodal irradiation (6). Mean dose was 37 Gy. There were 30 recurrences to give an acturial 10-year disease-free rate of 70%. In multivariate analysis lower number of tumour sites, lymphocyte predominant histology and higher dose were all significantly correlated with higher disease free rates. Eight patients died of Hodgkin's disease and 19 of other causes. The 10-year overall survival rate was 71%. Older age and higher number of disease sites were significantly correlated with shorter survival. Fourteen of 30 relapses may have been avoidable by the use of total nodal irradiation. In particular ten of 21 patients with abdominal disease relapsed in nodal sites which would have been covered by total nodal irradiation. CONCLUSIONS: The rate of control in IHD could perhaps be improved by avoiding involved field irradiation or by aggressive therapy with total nodal irradiation or combined modality chemo-irradiation in Stage II disease. Staging laparotomy does not appear to be indicated.

Abdominal Neoplasms↗

A randomized controlled trial of adjuvant portal vein cytotoxic perfusion in colorectal cancer.

In this randomized trial adjuvant cytotoxic portal vein perfusion in patients undergoing surgery for colorectal cancer without liver metastases was assessed to determine whether the incidence of metachronous liver metastases could be reduced and survival thereby improved. There were 127 control patients and 117 patients who received adjuvant perfusion. A further 13 patients were excluded following randomization because of cirrhosis in 1, liver metastases at laparotomy in 3 and technical problems with cannulation in 9. Dukes' staging and degree of differentiation were similar in the two groups. There were fewer liver metastases in the perfusion patients and overall survival was improved. However, the benefit appears to be greatest in patients with Dukes' B colon cancer.

Aged↗

Against customer service.

This essay examines the nature of service in medicine and the relationship between service and profit. "Customer service medicine" is identified with the interrelated views that 1) profit is or ought to be healthcare's fundamental concern and 2) the quality of medical service corresponds to the degree to which it produces a feeling of approval in patients. This position is contrasted with the more traditional "beneficence model," which holds that 1) service ought to be healthcare's fundamental concern and 2) the proper criterion of quality medical service is the alleviation, mitigation, or prevention of the human suffering that occasions illness. Five shortcomings in the customer service model are identified: 1) customer service advocates often appeal to an unsound "efficiency argument"; 2) the prioritization of profit over service will vitiate patients' legitimate trust in healthcare; 3) the prioritization of profit converts medicine from a "practice" into an "instrumental activity"; 4) the prioritization of profit countervails the values of continuity and thoroughness; and 5) the notion of service as customer satisfaction derives more from the exigencies of turning a profit than from an analysis of sick persons' needs.

Continuity of Patient Care↗

The goals of medicine.

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Economics, Medical↗