Comparison of manual and semi-automated delineation of regions of interest for radioligand PET imaging analysis

BACKGROUND As imaging centers produce higher resolution research scans, the number of man-hours required to process regional data has become a major concern. Comparison of automated vs. manual methodology has not been reported for functional imaging. We explored validation of using automation to delineate regions of interest on positron emission tomography (PET) scans. The purpose of this study was to ascertain improvements in image processing time and reproducibility of a semi-automated brain region extraction (SABRE) method over manual delineation of regions of interest (ROIs). METHODS We compared 2 sets of partial volume corrected serotonin 1a receptor binding potentials (BPs) resulting from manual vs. semi-automated methods. BPs were obtained from subjects meeting consensus criteria for frontotemporal degeneration and from age- and gender-matched healthy controls. Two trained raters provided each set of data to conduct comparisons of inter-rater mean image processing time, rank order of BPs for 9 PET scans, intra- and inter-rater intraclass correlation coefficients (ICC), repeatability coefficients (RC), percentages of the average parameter value (RM%), and effect sizes of either method. RESULTS SABRE saved approximately 3 hours of processing time per PET subject over manual delineation (p 0.8) for both methods. RC and RM% were lower for the manual method across all ROIs, indicating less intra-rater variance across PET subjects' BPs. CONCLUSION SABRE demonstrated significant time savings and no significant difference in reproducibility over manual methods, justifying the use of SABRE in serotonin 1a receptor radioligand PET imaging analysis. This implies that semi-automated ROI delineation is a valid methodology for future PET imaging analysis

Jointly Optimal Channel Pairing and Power Allocation for Multichannel Multihop Relaying

We study the problem of channel pairing and power allocation in a multichannel multihop relay network to enhance the end-to-end data rate. Both amplify-and-forward (AF) and decode-and-forward (DF) relaying strategies are considered. Given fixed power allocation to the channels, we show that channel pairing over multiple hops can be decomposed into independent pairing problems at each relay, and a sorted-SNR channel pairing strategy is sum-rate optimal, where each relay pairs its incoming and outgoing channels by their SNR order. For the joint optimization of channel pairing and power allocation under both total and individual power constraints, we show that the problem can be decoupled into two subproblems solved separately. This separation principle is established by observing the equivalence between sorting SNRs and sorting channel gains in the jointly optimal solution. It significantly reduces the computational complexity in finding the jointly optimal solution. It follows that the channel pairing problem in joint optimization can be again decomposed into independent pairing problems at each relay based on sorted channel gains. The solution for optimizing power allocation for DF relaying is also provided, as well as an asymptotically optimal solution for AF relaying. Numerical results are provided to demonstrate substantial performance gain of the jointly optimal solution over some suboptimal alternatives. It is also observed that more gain is obtained from optimal channel pairing than optimal power allocation through judiciously exploiting the variation among multiple channels. Impact of the variation of channel gain, the number of channels, and the number of hops on the performance gain is also studied through numerical examples.Comment: 15 pages. IEEE Transactions on Signal Processin

Jointly Optimal Channel Pairing and Power Allocation for Multichannel Multihop Relaying

We study the problem of channel pairing and power allocation in a multichannel multihop relay network to enhance the end-to-end data rate. Both amplify-and-forward (AF) and decode-and-forward (DF) relaying strategies are considered. Given fixed power allocation to the channels, we show that channel pairing over multiple hops can be decomposed into independent pairing problems at each relay, and a sorted-SNR channel pairing strategy is sum-rate optimal, where each relay pairs its incoming and outgoing channels by their SNR order. For the joint optimization of channel pairing and power allocation under both total and individual power constraints, we show that the problem can be decoupled into two subproblems solved separately. This separation principle is established by observing the equivalence between sorting SNRs and sorting channel gains in the jointly optimal solution. It significantly reduces the computational complexity in finding the jointly optimal solution. It follows that the channel pairing problem in joint optimization can be again decomposed into independent pairing problems at each relay based on sorted channel gains. The solution for optimizing power allocation for DF relaying is also provided, as well as an asymptotically optimal solution for AF relaying. Numerical results are provided to demonstrate substantial performance gain of the jointly optimal solution over some suboptimal alternatives. It is also observed that more gain is obtained from optimal channel pairing than optimal power allocation through judiciously exploiting the variation among multiple channels. Impact of the variation of channel gain, the number of channels, and the number of hops on the performance gain is also studied through numerical examples.Comment: 15 pages. IEEE Transactions on Signal Processin

Fire Plan: The Canadian Army’s Fire Support System in Normandy

Consigned initially to a decentralized and limited tactical role, the fire support organizations of British and Canadian armies experienced exponential growth during the initial stages of World War II. By D-Day, fire support had become a critical enabler of Anglo-Canadian combat operations and artillery units were numerous, networked, and efficient. Facilitating successful tactical manoeuvre was the goal of the fire support system. This article will explore the ‘ways’ and ‘means’ of that system – the people, procedures, resources, and organizations that combined to produce the devastating battle-winning fire support that contributed to tactical success

Monetary policy neglect and the Great Inflation in Canada, Australia, and New Zealand

This paper studies the Great Inflation in Canada, Australia, and New Zealand. Newspaper coverage and policymakers' statements are used to analyze the views on the inflation process that led to the 1970s macroeconomic policies, and the different movement in each country away from 1970s views. I argue that to understand the course of policy in each country, it is crucial to use the monetary policy neglect hypothesis, which claims that the Great Inflation occurred because policymakers delegated inflation control to nonmonetary devices. This hypothesis helps explain why, unlike Canada, Australia and New Zealand continued to suffer high inflation in the mid-1980s. The delayed disinflation in these countries reflected the continuing importance accorded to nonmonetary views of inflation.Monetary policy ; Inflation (Finance)

The B -> pi K Puzzle and New Physics

The present B -> pi K data is studied in the context of the standard model (SM) and with new physics (NP). We confirm that the SM has difficulties explaining the B -> pi K measurements. By adopting an effective-lagrangian parametrization of NP effects, we are able to rule out several classes of NP. Our model-independent analysis shows that the B -> pi K data can be accommodated by NP in the electroweak penguin sector.Comment: 4 pages (revtex

Racial Minority Immigrant Acculturation: Examining Filipino Settlement Experiences in Canada Utilizing a Community-Focused Acculturation Framework

By incorporating perspectives from Community Psychology into Berry’s (1997) acculturation framework from Cross-cultural Psychology, a more community-focused acculturation framework was developed and proposed in this essay. Elements from Community Psychology that focus on group-specific settings, community-level analysis, sociocultural resources, sociopolitical forces, and roles of grassroots organizations and host societies in challenging institutional power were consolidated into Berry’s acculturation framework to establish a new framework with a stronger community focus. In a theoretical application utilizing the new community-focused framework, socio-historical accounts of and discourse on Filipino experiences prior to the beginnings of the Filipino diaspora to Canada in the mid-1990s and more recent Filipino immigrant settlement experiences in Canada were used to examine and gain greater understanding of racial minority immigrant acculturation. The theoretical application of the new framework was presented not only to demonstrate the synthesis of elements derived from Cross-cultural and Community Psychology, as well as the methodological difference between Berry’s acculturation framework and the community-focused version proposed by the author, but also to underscore the value of community-level analysis in the study of racial minority immigrant acculturation. Implications for Psychology theory, research, and practice were subsequently presented