Persistent Mismatch Research Articles

Holding Global Regulators Accountable: The Case of Credit Rating Agencies

Credit Rating Agencies (CRAs) are private nonmajoritarian regulators (NMRs) of international capital markets. Ratings of creditworthiness are ubiquitous in financial markets, and in this way they exercise considerable control over the flow of credit. CRAs entail a puzzle for the question of the legitimacy of global regulation. As profit seeking firms, they lack a formal element of coercion. Yet, CRAs are often criticized for wielding illegitimate power. Furthermore, the broad demand for accountability has not had a great effect on how CRAs operate. Thus, there is a persistent mismatch between demand and supply of accountability, an “accountability gap.” By analyzing the accountability gap, this article seeks to enhance the understanding of the nature and the scope of the legitimacy problems of global NMRs. CRAs suggest that the legitimacy problems of global governance extend beyond formal NMRs to informal NMRs and that solutions sometimes are elusive.

Dynamic tracking of acute ischemic tissue fates using improved unsupervised ISODATA analysis of high-resolution quantitative perfusion and diffusion data.

High-resolution (200 x 200 x 1,500 microm3) imaging was performed to derive quantitative cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) maps in stroke rats (permanent occlusion) every 30 minutes up to 3 hours after occlusion onset, followed by histology at 24 hours. An improved automated iterative-self-organizing-data-analysis-algorithm (ISODATA) was developed to dynamically track ischemic tissue fate on a pixel-by-pixel basis during the acute phase. ISODATA-resolved clusters were overlaid on the CBF-ADC scatterplots and image spaces. Tissue volume ADC, and CBF of each ISODATA cluster were derived. In contrast to the single-cluster normal left hemisphere (ADC = 0.74 +/- 0.02 x 10(-3) mm2/s, CBF = 1.36 +/- 0.22 mL g(-1)min(-1), mean +/- SD, n = 8), the right ischemic hemisphere exhibited three ISODATA clusters, namely: "normal" (normal ADC and CBF), "ischemic core" (low CBF and ADC), and at-risk "perfusion-diffusion mismatch" (low CBF but normal ADC). At 180 minutes, the mismatch disappeared in five rats (Group I, 180-minute "core" lesion volume = 255 +/- 62 mm3 and 24-hour infarct volume = 253 +/- 55 mm3, P > 0.05), while a substantial mismatch persisted in three rats (Group II, 180-minute CBF-abnormal volume = 198 +/- 7 mm3 and 24-hour infarct volume 148 +/- 18 mm3, P < 0.05). The CBF (0.3 +/- 0.09 mL g(-1)min(-1)) of the "persistent mismatch" (Group II, 0.3 +/- 0.09 mL g(-1)min(-1)) was above the CBF viability threshold (0.2 to 0.3 mL g(-1)min(-1)) throughout and its ADC (0.70 +/- 0.03 x 10(-3) mm2/s) did not decrease as ischemia progressed. In contrast, the CBF (0.08 +/- 0.03 mL g(-1)min(-1)) of the analogous brain region in Group I was below the CBF viability threshold, and its ADC gradually decreased from 0.63 +/- 0.05 to 0.43 +/- 0.03 x 10(-3) mm2/s (ADC viability threshold = 0.53 +/- 0.02 x 10(-3) mm2/s). The modified ISODATA analysis of the ADC and CBF tissue characteristics during the acute phase could provide a useful and unbiased means to characterize and predict tissue fates in ischemic brain injury and to monitor therapeutic intervention.

Left atrial tumour mimicking pulmonary embolism

Primary cardiac tumours have been described as great imitators. They are rare, and clinical presentations are diverse. Diagnosis is usually made by two-dimensional echocardiography. The present case report describes a case where a left atrial fibrosarcoma eluded diagnosis by echocardiography, and was eventually demonstrated by computed tomography. Management was complicated by the presence of persistent mismatch demonstrated by ventilation-perfusion lung scans. The likely mechanism underlying this phenomenon is discussed.

Foreign Medical Graduates

To the Editor.— Dr. Hussey's editorial quotes a recommendation of the Association of American Medical Colleges task force, which is led by Kenneth Crispell, to the effect that a tighter control be exerted over the number and kinds of approved graduate training programs, in an effort to make an appropriate match between the number of positions offered and the projected physician manpower needs. This recommendation is destined for a persistent mismatch because the number of positions offered in residency programs reflects in great part the needs of hospitals in the care of acutely ill patients, while the "projected physician manpower needs" are related to the medical requirements of the general population, the overwhelming majority of whom are and continue to be in good health. The irrelevancy of the one to the other is very well illustrated by the medical or surgical resident who, the day after he finishes a very