Approximate Majority with Catalytic Inputs

Population protocols are a class of algorithms for modeling distributed computation in networks of finite-state agents communicating through pairwise interactions. Their suitability for analyzing numerous chemical processes has motivated the adaptation of the original population protocol framework to better model these chemical systems. In this paper, we further the study of two such adaptations in the context of solving approximate majority: persistent-state agents (or catalysts) and spontaneous state changes (or leaks). Based on models considered in recent protocols for populations with persistent-state agents, we assume a population with $n$ catalytic input agents and $m$ worker agents, and the goal of the worker agents is to compute some predicate over the states of the catalytic inputs. We call this model the Catalytic Input (CI) model. For $m = \Theta(n)$, we show that computing the parity of the input population with high probability requires at least $\Omega(n^2)$ total interactions, demonstrating a strong separation between the CI model and the standard population protocol model. On the other hand, we show that the simple third-state dynamics of Angluin et al. for approximate majority in the standard model can be naturally adapted to the CI model: we present such a constant-state protocol for the CI model that solves approximate majority in $O(n \log n)$ total steps with high probability when the input margin is $\Omega(\sqrt{n \log n})$. We then show the robustness of third-state dynamics protocols to the transient leaks events introduced by Alistarh et al. In both the original and CI models, these protocols successfully compute approximate majority with high probability in the presence of leaks occurring at each step with probability $\beta \leq O\left(\sqrt{n \log n}/n\right)$, exhibiting a resilience to leaks similar to that of Byzantine agents in previous works

An Argo mixed layer climatology and database

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 44 (2017): 5618–5626, doi:10.1002/2017GL073426.A global climatology and database of mixed layer properties are computed from nearly 1,250,000 Argo profiles. The climatology is calculated with both a hybrid algorithm for detecting the mixed layer depth (MLD) and a standard threshold method. The climatology provides accurate information about the depth, properties, extent, and seasonal patterns of global mixed layers. The individual profile results in the database can be used to construct time series of mixed layer properties in specific regions of interest. The climatology and database are available online at http://mixedlayer.ucsd.edu. The MLDs calculated by the hybrid algorithm are shallower and generally more accurate than those of the threshold method, particularly in regions of deep winter mixed layers; the new climatology differs the most from existing mixed layer climatologies in these regions. Examples are presented from the Labrador and Irminger Seas, the Southern Ocean, and the North Atlantic Ocean near the Gulf Stream. In these regions the threshold method tends to overestimate winter MLDs by approximately 10% compared to the algorithm.National Science Foundation (NSF) Grant Numbers: OCE-0327544, OCE-0960928, OCE-1459474; NOAA Grant Number: NA10OAR43101392017-12-1

Manifestations of coronary atherosclerosis in young trauma victims—An autopsy study

AbstractObjectives. The aim of this study was to look at the prevalence of coronary atherosclerosis, its severity aid site of involvement in patients <35 years old who died from noncardiac trauma.Background. Autopsies performed on casualties of the Korean War revealed coronary artery involvement in 77.3% of the hearts studied, and data after the Vietnam War noted the presence of atherosclerosis in 45% of casualties with severe disease in 5%, suggesting a decline in the prevalence of coronary atherosclerosis in young men.Methods. One hundred eleven victims of noncardiac trauma (86.4% white with a mean age of 26 ± 6 years) underwent pathologic examination of their coronary arteries to estimate the presence and severity of coronary atherosclerosis grossly, microscopically and through computerized planimetry. Identified segments of the coronary arteries were sectioned at 3-mm intervals, stained with special stains and after microscopic examination transferred to videotape and digitized to allow estimation of the percent compromise in the lumen area by atherosclerotic plaque.Results. Signs of coronary atherosclerosis were seen in 78.3% of the total study group, with >50% narrowing in 20.7% and >75% narrowing in 9%. No demographic or anatomic features seperated the groups with less or more severe involvement of their coronary arteries. Proximal involvement was more common except in the right coronary artery, which was as frequently involved distally.Conclusions. The overall prevalence of coronary atherosclerosis in a young, predominantly study group was comparable with that noted after the Korean War. Left main or significant two- and three-vessel involvement was noted in 20% of the group studied and emphasizes the need for aggressive risk factor modification in this group

Applying Value-Focused Thinking to a Make Versus Buy Decision

The United States Army placed emphasis on decreasing the load an individual Soldier carries by reducing the weight of ammunition through the use of polymer-cased ammunition.  This paradigm shift from brass to polymer raises concerns over the implementation aspect of this new procedure into the US Army’s current ammunition production process.  Our client, Project Manager Maneuver Ammunition Systems (PM-MAS) sponsored our team to analyze various candidate solutions using a methodology grounded in value-focused thinking, and recommend an implementation method to produce 7.62 mm polymer-cased ammunition at the Lake City Army Ammunition Plant (LCAAP) in Lake City, Missouri.  This paper outlines the application of systems thinking concepts, various problem definition techniques and value modeling in order to effectively compare three given scenarios using a total value score versus cost analysis for each candidate solution.  Our final recommendation is to implement the Buy scenario because of its total score of 63.5 and estimated cost of $14.62 million. 

Initial validation of a diagnostic questionnaire for gastroesophageal reflux disease

Brief, reliable, and valid self-administered questionnaires could facilitate the diagnosis of gastroesophageal reflux disease in primary care. We report the development and validation of such an instrument. Methods Content validity was informed by literature review, expert opinion, and cognitive interviewing of 50 patients resulting in a 22-item survey. For psychometric analyses, primary care patients completed the new questionnaire at enrollment and at intervals ranging from 3 days to 3 wk. Multitrait scaling, test–retest reliability, and responsiveness were assessed. Predictive validity analyses of all scales and items used specialty physician diagnosis as the “gold standard.” Results Iterative factor analyses yielded three scales of four items each including heartburn, acid regurgitation, and dyspepsia. Multitrait scaling criteria including internal consistency, item interval consistency, and item discrimination were 100% satisfied. Test–retest reliability was high in those reporting stable symptoms. Scale scores significantly changed in those reporting a global change. Regressing specialty physician diagnosis on the three scales revealed significant effects for two scales (heartburn and regurgitation). Combining the two significant scales enhanced the strength of the model. Symptom response to self-directed treatment with nonprescription antisecretory medications was highly predictive of the diagnosis also, although the item demonstrated poor validity and reliability. Conclusions A brief, simple 12-item questionnaire demonstrated validity and reliability and seemed to be responsive to change for reflux and dyspeptic symptoms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72526/1/j.1572-0241.2001.03451.x.pd

(E)-Benzaldehyde O-{[3-(pyridin-3-yl)isoxazol-5-yl]meth­yl}oxime

The asymmetric unit of the title compound, C16H13N3O2, contains two independent mol­ecules in which the pyridine and benzene rings form dihedral angles of 81.7 (2) and 79.8 (2)°, indicating the twist in the mol­ecules. In the crystal, weak C—H⋯N inter­actions link mol­ecules into chains along [100]

The State of the Region: Hampton Roads 2001

This is Old Dominion University\u27s second annual State of the Region Report. While it represents the work of many individuals connected in various ways to the university, the Report does not constitute an official viewpoint of the University, or it\u27s president, Dr. Roseann Runte. This year\u27s Report was produced with the goal of making Hampton Roads an even better place to live. Those who know and love the region of Hampton Roads frequently boast of its numerous strengths and successes, but we do so with the understanding that it would be possible for us to improve the region\u27s performance in certain areas. However, in order to improve our situation, we must have accurate knowledge about where we are, and what the policy implications are of the various choices in front of us. This year\u27s Report should be quite helpful in supplying such information. At the end of the day, we hope to have stimulated thought and discussion about things that matter.https://digitalcommons.odu.edu/economics_books/1017/thumbnail.jp

The State of the Region: Hampton Roads 2000

Those who know and love the region of Hampton Roads wish to make it an even better place to live than it is currently. In order for us to achieve that end, we must know literally where we are in critical areas. This first State of the Region Report is designed to provide citizens with a detailed, though not burdensome, look at several critical aspects of the lives we live in Hampton Roads. The Report focuses on topics such as the regional economy (including the tourist and military sectors), the workforce, K-12 education, technology, and of course, government and regional cooperation.https://digitalcommons.odu.edu/economics_books/1018/thumbnail.jp