Tracking of the Internal Jugular Vein in Ultrasound Images Using Optical Flow

Detection of relative changes in circulating blood volume is important to guide resuscitation and manage variety of medical conditions including sepsis, trauma, dialysis and congestive heart failure. Recent studies have shown that estimates of circulating blood volume can be obtained from ultrasound imagery of the of the internal jugular vein (IJV). However, segmentation and tracking of the IJV is significantly influenced by speckle noise and shadowing which introduce uncertainty in the boundaries of the vessel. In this paper, we investigate the use of optical flow algorithms for segmentation and tracking of the IJV and show that the classical Lucas-Kanade (LK) algorithm provides the best performance among well-known flow tracking algorithms.Comment: 4 pages, 7 figures, CCECE201

Subsidizing Public Inputs

Investment in research and development may (with some probability) lead to reductions in a firm’s production cost. If the production-cost savings associated with successful research and development is freely disseminated to other firms as soon as it is realized, too few resources may be allocated to this input. In such an environment, subsidies to the public input can lead to optimal input use. Four alternative subsidy instruments are considered in this paper. Two are incremental subsidies and the others are conventional level subsidies. One of the incremental subsidies and one of the level subsidies crudely capture characteristics of incentive mechanisms used in the United States and Canada. A laboratory implementation of these instruments generally confirms that incremental subsidies are inferior to level subsidies.

Estimation and Tracking of AP-diameter of the Inferior Vena Cava in Ultrasound Images Using a Novel Active Circle Algorithm

Medical research suggests that the anterior-posterior (AP)-diameter of the inferior vena cava (IVC) and its associated temporal variation as imaged by bedside ultrasound is useful in guiding fluid resuscitation of the critically-ill patient. Unfortunately, indistinct edges and gaps in vessel walls are frequently present which impede accurate estimation of the IVC AP-diameter for both human operators and segmentation algorithms. The majority of research involving use of the IVC to guide fluid resuscitation involves manual measurement of the maximum and minimum AP-diameter as it varies over time. This effort proposes using a time-varying circle fitted inside the typically ellipsoid IVC as an efficient, consistent and novel approach to tracking and approximating the AP-diameter even in the context of poor image quality. In this active-circle algorithm, a novel evolution functional is proposed and shown to be a useful tool for ultrasound image processing. The proposed algorithm is compared with an expert manual measurement, and state-of-the-art relevant algorithms. It is shown that the algorithm outperforms other techniques and performs very close to manual measurement.Comment: Published in Computers in Biology and Medicin

The Impact of Social Value Orientation and Risk Attitudes on Trust and Reciprocity

Prior experimental studies provide evidence that the levels of trust and reciprocity are highly susceptible to individuals’ preferences towards payoffs, prior experience, capacity to learn more about personal characteristics of each other and social distance. The objective of this study is to examine whether social value orientation as developed by Griesinger and Livingstone (1973) and Liebrand (1984) and risk preferences can help to account for the variability of trust and trustworthiness. We use the Berg et al. (1995) investment game to generate indices of trust and reciprocity. Prior to their participation in the investment game, all subjects participated in two other games. One is used to measure their social value orientation (a measure of other regarding behavior) and the second to measure risk attitudes. These variables are introduced as treatments in the analysis of the trust and reciprocity data. In addition to these preference related variables, gender is introduced to capture any differences between men and women which may not be encompassed by value orientation and risk attitudes. The statistical analysis indicates that the social value orientation measure significantly accounts for variation in trust and reciprocity. As well, the level of trust exhibited by an investor significantly affects the reciprocity of the responders and this measure of trust interacts with social value orientation. Individuals who are highly pro-social reciprocate more as the sender’s trust increases, while those who are highly pro-self reciprocate less as the sender’s trust increases. For this sample of participants, the gender variable does not capture any differences in the behavior of men and women that is not already reflected by the differences captured by their value orientations. Risk attitudes do not significantly account for variation in trusting behavior, except for the case where individuals have neither strongly pro-social nor pro-self social value orientations. In this case, more riskseeking individuals are more trusting.Trust, Reciprocity, Social Value Orientation, Risk Attitudes, Gender

Trust and Reciprocity with Transparency and Repeated Interactions

This paper uses data from a controlled laboratory environment to study the impact of transparency (i.e., complete information versus incomplete information) and repeated interactions on the level of trust and trustworthiness in an investment game setting. The key findings of the study are that transparency (complete information) significantly increases trusting behavior in one-shot interactions. This result persists in repeated interactions. Further, transparency appears important for trustworthiness in one-shot interactions. In addition, repeated interaction increases trust and reciprocity with or without transparency. These results suggest transparency is important in building trust in business environments such as alliances and joint-ventures which are loosely connected organizational forms that bring together otherwise independent firms. It also provides support for the Sarbanes-Oxley Act of 2002 (SOX) and similar legislation elsewhere which attempt to regain investors’ trust in corporate management and financial markets by stipulating enhanced disclosures.Transparency; Trust; Reciprocity; Repeated interaction; Business Alliances; SOX

The Impact of Empowering Investors on Trust and Trustworthiness

This paper uses laboratory mechanism design in an investment environment to examine the impact of empowering investors with the right to veto the investee’s profit distribution decision on the level of trust and trustworthiness. One of the key findings is that the empowerment of investors through both costless and costly vetoes significantly increases trust by over 30% in both cases. Interestingly, we observe a comparable pattern when the power to veto is removed. Analyses of veto decisions indicate that empowering investors increases both trust and trustworthiness without an undue abuse of the power to veto and that the veto decisions are largely driven by unfair responses, consistent with the theory on inequity aversion.Empowerment; Veto; Investment; Trust; Trustworthiness; Reciprocity