Gradualism and irreversibility

This paper considers a class of two-player dynamic games in which each player controls a one-dimensional variable which we interpret as a level of cooperation. In the base model, there is an irreversibility constraint stating that this variable can never be reduced, only increased. It otherwise satisfies the usual discounted repeated game assumptions. Under certain restrictions on the payoff function, which make the stage game resemble a continuous version of the Prisoners’ Dilemma, we characterize efficient symmetric equilibria, and show that cooperation levels exhibit gradualism and converge, when payoffs are smooth, to a level strictly below the one-shot efficient level: the irreversibility induces a steady-state as well as a dynamic inefficiency. As players become very patient, however, payoffs converge to (though never attain) the efficient level. We also show that a related model in which an irreversibility arises through players choosing an incremental variable, such as investment, can be transformed into the base model with similar results. Applications to a public goods sequential contribution model and a model of capacity reduction in a declining industry are discussed. The analysis is extended to incorporate partial reversibility, asymmetric equilibria, and sequential moves

Fast Packet Classification Using Bloom Filters

While the problem of general packet classification has received a great deal of attention from researchers over the last ten years, there is still no really satisfactory solution. Ternary Content Addressable Memory (TCAM), although widely used in practice, is both expensive and consumes a lot of power. Algorithmic solutions, which rely on commodity memory chips, are relatively inexpensive and power-efficient, but have not been able to match the generality and performance of TCAMs. In this paper we propose a new approach to packet classification, which combines architectural and algorithmic techniques. Our starting point is the well-known crossproducting algorithm, which is fast but has significant memory overhead due to the extra rules needed to represent the crossproducts. We show how to modify the crossproduct method in a way that drastically reduces the memory required, without compromising on performance. We avoid unnecessary accesses to off-chip memory by filtering off-chip accesses using on-chip Bloom filters. For packets that match p rules in a rule set, our algorithm requires just 4 + p + ǫ independent memory accesses on average, to return all matching rules, where ǫ á 1 is a small constant that depends on the false positive rate of the Bloom filters. Each memory access is just 256 bits, making it practical to classify small packets at OC-192 link rates using two commodity SRAM chips. For rule set sizes ranging from a few hundred to several thousand filters, the average rule set expansion factor attributable to the algorithm is just 1.2. The memory consumption per rule is 36 bytes in the average case

Projected Utility of the Ready Set Return Application

Introduction: An application (app) that summarizes best practices may promote standardized care among clinicians treating patients during anterior cruciate ligament (ACL) rehabilitation. The purpose of this study was to test the prototype of the Ready Set Return (RSR) app to determine receptiveness for use in clinical practice. Methods: Two mock patient cases were used to familiarize 19 physical therapists and athletic trainers with the RSR app. Then these participants provided feedback about the user experience, features, and content using Likert ratings and free-text fields through an online survey. Results: Most participants (89%-95%) would recommend the RSR app to others and noted that the app would allow them to stay up to date with current practice. Thematic analysis of free-text responses indicated that the app was easy to navigate and that evidence-based progressions and clinical milestones were useful in clinical practice. Users suggested enhancements that included adding patient access and specific treatment options. Discussion: Generalizable findings suggest that clinicians appreciated the details and images of specific tests and measures; automatic test scoring; and standardized benchmarks to progress care. Specific findings suggest the RSR app’s summary of evidence-informed practice may help standardize care, specifically for patients undergoing rehabilitation after ACL reconstruction. Conclusion: This subset of clinicians reacted positively to the prototype and felt that the RSR app would benefit their practice and patients. This feedback will guide the next iteration, advancing from a low-fidelity to high-fidelity prototype

System-on-Chip Packet Processor for an Experimental Network Services Platform

As the focus of networking research shifts from raw performance to the delivery of advanced network services, there is a growing need for open-platform systems for extensible networking research. The Applied Research Laboratory at Washington University in Saint Louis has developed a flexible Network Services Platform (NSP) to meet this need. The NSP provides an extensible platform for prototyping next-generation network services and applications. This paper describes the design of a system-on-chip Packet Processor for the NSP which performs all core packet processing functions including segmentation and reassembly, packet classification, route lookup, and queue management. Targeted to a commercial configurable logic device, the system is designed to support gigabit links and switch fabrics with a 2:1 speed advantage. We provide resource consumption results for each component of the Packet Processor design

Senior Recital: John Thomas Burson, trumpet

This recital is presented in partial fulfillment of requirements for the degree Bachelor of Music in Performance. Mr. Burson studies trumpet with Douglas Lindsey.https://digitalcommons.kennesaw.edu/musicprograms/1517/thumbnail.jp

SIGMA: A System for Integrative Genomic Microarray Analysis of Cancer Genomes

BACKGROUND: The prevalence of high resolution profiling of genomes has created a need for the integrative analysis of information generated from multiple methodologies and platforms. Although the majority of data in the public domain are gene expression profiles, and expression analysis software are available, the increase of array CGH studies has enabled integration of high throughput genomic and gene expression datasets. However, tools for direct mining and analysis of array CGH data are limited. Hence, there is a great need for analytical and display software tailored to cross platform integrative analysis of cancer genomes. RESULTS: We have created a user-friendly java application to facilitate sophisticated visualization and analysis such as cross-tumor and cross-platform comparisons. To demonstrate the utility of this software, we assembled array CGH data representing Affymetrix SNP chip, Stanford cDNA arrays and whole genome tiling path array platforms for cross comparison. This cancer genome database contains 267 profiles from commonly used cancer cell lines representing 14 different tissue types. CONCLUSION: In this study we have developed an application for the visualization and analysis of data from high resolution array CGH platforms that can be adapted for analysis of multiple types of high throughput genomic datasets. Furthermore, we invite researchers using array CGH technology to deposit both their raw and processed data, as this will be a continually expanding database of cancer genomes. This publicly available resource, the System for Integrative Genomic Microarray Analysis (SIGMA) of cancer genomes, can be accessed at

Tinnitus Perception and Distress Is Related to Abnormal Spontaneous Brain Activity as Measured by Magnetoencephalography

BACKGROUND: The neurophysiological mechanisms underlying tinnitus perception are not well understood. Surprisingly, there have been no group studies comparing abnormalities in ongoing, spontaneous neuronal activity in individuals with and without tinnitus perception. METHODS AND FINDINGS: Here, we show that the spontaneous neuronal activity of a group of individuals with tinnitus (n = 17) is characterised by a marked reduction in alpha (8–12 Hz) power together with an enhancement in delta (1.5–4 Hz) as compared to a normal hearing control group (n = 16). This pattern was especially pronounced for temporal regions. Moreover, correlations with tinnitus-related distress revealed strong associations with this abnormal spontaneous activity pattern, particularly in right temporal and left frontal areas. Overall, effects were stronger for the alpha than for the delta frequency band. A data stream of 5 min, recorded with a whole-head neuromagnetometer under a resting condition, was sufficient to extract the marked differences. CONCLUSIONS: Despite some limitations, there are arguments that the regional pattern of abnormal spontaneous activity we found could reflect a tinnitus-related cortical network. This finding, which suggests that a neurofeedback approach could reduce the adverse effects of this disturbing condition, could have important implications for the treatment of tinnitus

Resident and teacher perceptions of the preceptor field note: a qualitative analysis

Implication Statement Assessment of clinical teachers is a requirement by family medicine residency programs in Canada. This facilitates feedback to teachers and ensures the curriculum is delivered in an efficient and safe way. To protect resident confidentiality, preceptors often receive their teaching evaluations months to years later. Teachers have requested shorter feedback loops, greater numbers, and more frequent assessments to improve their skills. The preceptor field note (PFN) is a tool that allows learners to evaluate teachers during a single encounter providing more frequent and immediate feedback. This study documents teachers’ and residents’ initial impressions of the first iteration of the PFN

Macrophages enhance Vegfa-driven angiogenesis in an embryonic zebrafish tumour xenograft model

Tumour angiogenesis has long been a focus of anti-cancer therapy; however, anti-angiogenic cancer treatment strategies have had limited clinical success. Tumour-associated myeloid cells are believed to play a role in the resistance of cancer towards anti-angiogenesis therapy, but the mechanisms by which they do this are unclear. An embryonic zebrafish xenograft model has been developed to investigate the mechanisms of tumour angiogenesis and as an assay to screen anti-angiogenic compounds. In this study, we used cell ablation techniques to remove either macrophages or neutrophils and assessed their contribution towards zebrafish xenograft angiogenesis by quantitating levels of graft vascularisation. The ablation of macrophages, but not neutrophils, caused a strong reduction in tumour xenograft vascularisation and time-lapse imaging demonstrated that tumour xenograft macrophages directly associated with the migrating tip of developing tumour blood vessels. Finally, we found that, although macrophages are required for vascularisation in xenografts that either secrete VEGFA or overexpress zebrafish vegfaa, they are not required for the vascularisation of grafts with low levels of VEGFA, suggesting that zebrafish macrophages can enhance Vegfa-driven tumour angiogenesis. The importance of macrophages to this angiogenic response suggests that this model could be used to further investigate the interplay between myeloid cells and tumour vascularisation