Compositional Reasoning for Explicit Resource Management in Channel-Based Concurrency

We define a pi-calculus variant with a costed semantics where channels are treated as resources that must explicitly be allocated before they are used and can be deallocated when no longer required. We use a substructural type system tracking permission transfer to construct coinductive proof techniques for comparing behaviour and resource usage efficiency of concurrent processes. We establish full abstraction results between our coinductive definitions and a contextual behavioural preorder describing a notion of process efficiency w.r.t. its management of resources. We also justify these definitions and respective proof techniques through numerous examples and a case study comparing two concurrent implementations of an extensible buffer.Comment: 51 pages, 7 figure

D.C. Circuit: Study of Gender, Race, and Ethnic Bias

The District of Columbia Circuit became the first federal circuit to establish a Task Force on race and gender bias. In 1992, the Task Force, which was comprised of judges from the D.C. Circuit, created two committees-the Special Committee on Gender and the Special Committee on Race and Ethnicity-to assist the Task Force in its research. The committees were comprised of academics, social science advisors of national recognition, and leading attorneys

Testing for Evidence of Maternal Effects among Individuals and Populations of White Crappie

For an increasing number of species, maternal characteristics have been correlated with the characteristics of their eggs or larvae at the individual level. Documenting these maternal effects at the population level, however, is uncommon. For white crappies Pomoxis annularis, we evaluated whether individual maternal effects on eggs existed and then explored whether incorporating maternal effects explained additional variation in recruitment, a population-level response. Individual egg quality (measured as ovary energy density) increased with maternal length among individuals from seven Ohio reservoirs in 1999 and three in 2000. Among these same individuals, egg quality increased with maternal condition factor (measured as residual wet mass for a given length) in 1999 but not in 2000. In 2000 we estimated somatic energy density, an improved measure of condition; egg quality increased with somatic energy density, but somatic energy density was also strongly correlated with maternal length. Hence, we could not determine whether maternal length or condition was the primary factor influencing white crappie egg quality. Across seven populations, the relative population fecundity (i.e., stock size) of the 1999 year-class was unable to explain the variation in recruitment to age 2 (Ricker model r^2 = 0.04 and Beverton and Holt model r^2 = 0.02). Mean ovary energy density (i.e., egg quality), however, was unable to explain additional recruitment variability in either model. Hence, we documented evidence of maternal effects on individual ovaries but not on population-level recruitment. Nonetheless, we recommend that future studies seeking to understand white crappie recruitment continue to consider maternal effects as a potential factor, especially those studies that may have greater sample sizes at the population level and, in turn, a greater probability of documenting a population-level effect.This research was funded by Federal Aid in Sport Fish Restoration Project F-69-P, administered jointly by U.S. Fish and Wildlife Service and Ohio Department of Natural Resources, Division of Wildlife and the Department of Evolution, Ecology, and Organismal Biology at Ohio State University

Reasoning about explicit resource management

We investigate the behaviour and efficiency of concurrent processes with explicit resource management. Our study is based on a π-calculus variant called Rπ [4] where the only resources available are channels, which must be explicitly allocated before they can be used and can be deallocated when no longer required. A substructural type system guarantees the safe allocation and deallocation of channels, as well as safe channel reuse through strong updates. In this paper we use this type system to give compositional proof techniques for reasoning about the behaviour and efficiency of Rπ processes.peer-reviewe

Integrated multi-trophic aquaculture mitigates the effects of ocean acidification: Seaweeds raise system pH and improve growth of juvenile abalone

Integrated multi-trophic aquaculture (IMTA) has the potential to enhance growth, reduce nutrient loads, and mitigate environmental conditions compared to traditional single-species culture techniques. The goal of this project was to develop a land-based system for the integrated culture of seaweeds and shellfish, to test the efficacy of integrated versus non-integrated designs, and to assess the potential for IMTA to mitigate the effects of climate change from ocean acidification on shellfish growth and physiology. We utilized the red abalone (Haliotis rufescens) and the red seaweed dulse (Devaleraea mollis) as our study species and designed integrated tanks at three different recirculation rates (0%, 30%, and 65% recirculation per hour) to test how an integrated design would affect growth rates of the abalone and seaweeds, modify nutrient levels, and change water chemistry. We specifically hypothesized that IMTA designs would raise seawater pH to benefit calcifying species. Our results indicated that juvenile abalone grew significantly faster in weight (22% increase) and shell area (11% increase) in 6 months in tanks with the highest recirculation rates (65%). The 65% recirculation treatment also exhibited a significant increase in mean seawater pH (0.2 pH units higher) due to the biological activity of the seaweed in the connected tanks. We found a significant positive relationship between the mean pH of seawater in the tanks and juvenile abalone growth rates across all treatments. There were no significant differences in the growth of dulse among treatments, but dulse growth did vary seasonally. Seawater phosphate and nitrate concentrations were depleted in the highest recirculation rate treatment, but ammonium concentrations were elevated, likely due to the abalone effluent. Overall, our results indicate that there are benefits to IMTA culture of seaweeds and abalone in terms of improving growth in land-based systems, which will reduce the time to market and buffer commercial abalone operations against the effects of ocean acidification during vulnerable early life stages

Global estimate of submarine groundwater discharge based on an observationally constrained radium isotope model

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geophysical Research Letters 41 (2014): 8438–8444, doi:10.1002/2014GL061574.Along the continental margins, rivers and submarine groundwater supply nutrients, trace elements, and radionuclides to the coastal ocean, supporting coastal ecosystems and, increasingly, causing harmful algal blooms and eutrophication. While the global magnitude of gauged riverine water discharge is well known, the magnitude of submarine groundwater discharge (SGD) is poorly constrained. Using an inverse model combined with a global compilation of 228Ra observations, we show that the SGD integrated over the Atlantic and Indo-Pacific Oceans between 60°S and 70°N is (12 ± 3) × 1013 m3 yr−1, which is 3 to 4 times greater than the freshwater fluxes into the oceans by rivers. Unlike the rivers, where more than half of the total flux is discharged into the Atlantic, about 70% of SGD flows into the Indo-Pacific Oceans. We suggest that SGD is the dominant pathway for dissolved terrestrial materials to the global ocean, and this necessitates revisions for the budgets of chemical elements including carbon.This work was supported by the Ministry of Oceans and Fisheries, Korea, through the Korea Institute of Marine Science and Technology (KIMST) (20120176) and National Research Foundation (NRF) of Korea (2013R1A2A1A05004343 and 2013R1A1A1058203). Charette and Moore's contributions were supported by the US National Science Foundation through the GEOTRACES project

Segmented Aperture Interferometric Nulling Testbed (SAINT) II: Component Systems Update

"This work presents updates to the coronagraph and telescope components of the Segmented Aperture Interfer-ometric Nulling Testbed (SAINT). The project pairs an actively-controlled macro-scale segmented mirror withthe Visible Nulling Coronagraph (VNC) towards demonstrating capabilities for the future space observatoriesneeded to directly detect and characterize a significant sample of Earth-sized worlds around nearby stars inthe quest for identifying those which may be habitable and possibly harbor life. Efforts to improve the VNCwavefront control optics and mechanisms towards repeating narrowband results are described. A narrative isprovided for the design of new optical components aimed at enabling broadband performance. Initial work withthe hardware and software interface for controlling the segmented telescope mirror is also presented.