FlashLight: A Dynamic Detector of Shared State, Race Conditions, and Locking Models in Concurrent Java Programs

Concurrent Java programs are difficult to understand and implement correctly. This difficultly leads to code faults that are the source of many real-world reliability and security problems. Many factors contribute to concurrency faults in Java code; for example, programmers may not understand Java language semantics or, when using a Java library or framework, may not understand that their resulting program is concurrent. This thesis describes a dynamic analysis tool, named FlashLight, that detects shared state and possible race conditions within a program. FlashLight illuminates the concurrency within a program for programmers who are wholly or partially in the dark about their software\u27s concurrency. FlashLight also works in concert with the Fluid assurance tool to propose Greenhouse-style lock policy models based on a program\u27s observed locking behavior. After review by a programmer to ensure reasonableness, these models can be verified by the Fluid assurance tool. The author\u27s combination of a dynamic tool with a program verification system focused on concurrency fault detection and repair is the primary contribution of this research. He applied FlashLight to several concurrent Java programs, including a large commercial web application server. His case study experiences induced him to improve FlashLight to do the following: (1) allow the programmer to specify interesting time quantums (e.g., this is the start-up phase of the program), and (2) support the common Java programming idiom of not locking shared state during object construction. Both improvements help to reduce false positives. FlashLight introduces an overhead of roughly 1.7 times the original execution time of the program. The most significant limitation of FlashLight is that it is not fully integrated into the Fluid assurance tool with respect to the user experience

Moving lattice kinks and pulses: an inverse method

We develop a general mapping from given kink or pulse shaped travelling-wave solutions including their velocity to the equations of motion on one-dimensional lattices which support these solutions. We apply this mapping - by definition an inverse method - to acoustic solitons in chains with nonlinear intersite interactions, to nonlinear Klein-Gordon chains, to reaction-diffusion equations and to discrete nonlinear Schr\"odinger systems. Potential functions can be found in at least a unique way provided the pulse shape is reflection symmetric and pulse and kink shapes are at least $C^2$ functions. For kinks we discuss the relation of our results to the problem of a Peierls-Nabarro potential and continuous symmetries. We then generalize our method to higher dimensional lattices for reaction-diffusion systems. We find that increasing also the number of components easily allows for moving solutions.Comment: 15 pages, 5 figure

Wide-field dynamic astronomy in the near-infrared with Palomar Gattini-IR and DREAMS

There have been a dramatic increase in the number of optical and radio transient surveys due to astronomical transients such as gravitational waves and gamma ray bursts, however, there have been a limited number of wide-field infrared surveys due to narrow field-of-view and high cost of infrared cameras, we present two new wide-field near-infrared fully automated surveyors; Palomar Gattini-IR and the Dynamic REd All-sky Monitoring Survey (DREAMS). Palomar Gattini-IR, a 25 square degree J-band imager that begun science operations at Palomar Observatory, USA in October 2018; we report on survey strategy as well as telescope and observatory operations and will also providing initial science results. DREAMS is a 3.75 square degree wide-field imager that is planned for Siding Spring Observatory, Australia; we report on the current optical and mechanical design and plans to achieve on-sky results in 2020. DREAMS is on-track to be one of the first astronomical telescopes to use an Indium Galium Arsenide (InGaAs) detector and we report initial on-sky testing results for the selected detector package. DREAMS is also well placed to take advantage and provide near-infrared follow-up of the LSST

Structural Controls on Shallow Cenozoic Fluid Flow in the Otago Schist, New Zealand

The Otago Schist in the South Island of New Zealand represents an exhumed Mesozoic accretionary prism. Two coastal areas (Akatore Creek and Bruce Rocks) south of Dunedin preserve structural and geochemical evidence for the development of postmetamorphic hydrothermal systems that involved widespread fluid-rock reaction at shallow crustal depths. The Jurassic to Triassic pumpellyite-actinolite (Akatore Creek) to upper greenschist facies (Bruce Rocks) metamorphic fabrics were crosscut by sets of regionally extensive Cretaceous exhumation joints. Many of the joints were subsequently reactivated to form networks of small-displacement (<metres) strike-slip faults containing cemented fault breccias and veins composed of hydrothermal calcite, siderite, and ankerite. Paleostress analysis performed on infrequent fault slickenlines indicates an overall strike-slip paleostress regime and a paleo-σ1 orientation (azimuth 094°) similar to the contemporary σ1 orientation in Otago and Canterbury (azimuth c. 110°-120°). High δ18O values in vein calcite (δ18OVPDB=21 to 28‰), together with the predominance of Type I calcite twins, suggest that vein formation occurred at low temperatures (<200°C) in the shallow crust and was associated with strongly channelized fluid flow along the joint and fault networks. Mass-balance calculations performed on samples from carbonate alteration zones show that significant mobilisation of elements occurred during fluid flow and fluid-rock reaction. Whole-rock and in situ carbonate 87Sr/86Sr data indicate varying degrees of interaction between the hydrothermal fluids and the host rock schists. Fluids were likely derived from the breakdown of metamorphic Ca-rich mineral phases with low 87Rb in the host schists (e.g., epidote or calcite), as well as more radiogenic components such as mica. Overall, the field and geochemical data suggest that shallow fluid flow in the field areas was channelized along foliation surfaces, exhumation joints, and networks of brittle faults, and that these structures controlled the distribution of fluid-rock reactions and hydrothermal veins. The brittle fault networks and associated hydrothermal systems are interpreted to have formed after the onset of Early Miocene compression in the South Island and may represent the manifestation of fracturing and fluid flow associated with reverse reactivation of regional-scale faults such as the nearby Akatore Fault

Extrasolar planet population synthesis IV. Correlations with disk metallicity, mass and lifetime

Context. This is the fourth paper in a series showing the results of planet population synthesis calculations. Aims. Our goal in this paper is to systematically study the effects of important disk properties, namely disk metallicity, mass and lifetime on fundamental planetary properties. Methods. For a large number of protoplanetary disks we calculate a population of planets with our core accretion formation model including planet migration and disk evolution. Results. We find a large number of correlations: Regarding the planetary initial mass function, metallicity, disk mass and disk lifetime have different roles: For high [Fe/H], giant planets are more frequent. For high disk masses, giant planets are more massive. For long disk lifetimes, giant planets are both more frequent and massive. At low metallicities, very massive giant planets cannot form, but otherwise giant planet mass and metallicity are uncorrelated. In contrast, planet masses and disk gas masses are correlated. The sweet spot for giant planet formation is at 5 AU. In- and outside this distance, higher planetesimals surface densities are necessary. Low metallicities can be compensated by high disk masses, and vice versa, but not ad infinitum. At low metallicities, giant planets only form outside the ice line, while at high metallicities, giant planet formation occurs throughout the disk. The extent of migration increases with disk mass and lifetime and usually decreases with metallicity. No clear correlation of metallicity and the semimajor axis of giant planets exists because in low [Fe/H] disks, planets start further out, but migrate more, whereas for high [Fe/H] they start further in, but migrate less. Close-in low mass planets have a lower mean metallicity than Hot Jupiters. Conclusions. The properties of protoplanetary disks are decisive for the properties of planets, and leave many imprints.Comment: 23 pages, 16 figures. Accepted for A&

Seasonal Consumptive Demand and Prey Use by Stocked Saugeyes in Ohio Reservoirs

Community structure and species composition may be strongly influenced by predator-prey interactions resulting from and leading to episodes of population abundance or scarcity. We quantified diets of stocked saugeyes (female walleye Sander vitreus × male sauger S. canadensis) and estimated biomass of their primary prey, gizzard shad Dorosoma cepedianum, in three Ohio reservoirs at quarterly intervals during July 2002-July 2003 to determine whether saugeye consumptive demand could exceed the supply of available gizzard shad prey, resulting in a shift to alternative prey. We incorporated water temperature and saugeye diet composition, growth, and mortality into walleye bioenergetics models, which allowed us to compare estimated prey-specific consumption rates by saugeyes with gizzard shad standing stocks estimated with acoustics. Spring and summer were critical seasons. During spring, gizzard shad biomass was low, saugeye consumptive demand was low, and saugeyes consumed primarily alternative prey. During summer, when age-0 gizzard shad became available as prey, saugeyes consumed similar proportions of gizzard shad and alternative prey. Saugeye cumulative consumptive demand in summer was high and approached the gizzard shad standing stock. However, during fall and winter, gizzard shad supply was adequate to support high (fall) or declining (winter) saugeye consumptive demand. Across reservoirs and seasons, saugeyes consumed alternative prey to varying degrees, primarily sunfishes Lepomis spp., yellow perch Perca flavescens, logperch Percina caprodes, and minnows Pimephales spp. Seasonal asynchrony between saugeye consumptive demand and gizzard shad biomass during spring and summer indicated that a saugeye population with high survival, growth, and consumptive demand will opportunistically increase use of prey other than gizzard shad. The manner in which saugeye predation quantitatively influences these prey species could not be assessed. However, overexploitation of gizzard shad prey appears to be unlikely at current saugeye population sizes, particularly considering the opportunistic use of alternative prey and the high reproductive potential of gizzard shad.Funding for this research was provided by the Ohio Department of Natural Resources, Division of Wildlife; Federal Aid in Sport Fish Restoration Project F-69-P, Fish Management in Ohio; and the Department of Evolution, Ecology, and Organismal Biology at The Ohio State University

Discovery of an intermediate-luminosity red transient in M51 and its likely dust-obscured, infrared-variable progenitor

We present the discovery of an optical transient (OT) in Messier 51, designated M51 OT2019-1 (also ZTF19aadyppr, AT 2019abn, ATLAS19bzl), by the Zwicky Transient Facility (ZTF). The OT rose over 15 days to an observed luminosity of $M_r=-13$ (${\nu}L_{\nu}=9\times10^6~L_{\odot}$), in the luminosity gap between novae and typical supernovae (SNe). Spectra during the outburst show a red continuum, Balmer emission with a velocity width of $\approx400$ km s$^{-1}$, Ca II and [Ca II] emission, and absorption features characteristic of an F-type supergiant. The spectra and multiband light curves are similar to the so-called "SN impostors" and intermediate-luminosity red transients (ILRTs). We directly identify the likely progenitor in archival Spitzer Space Telescope imaging with a $4.5~\mu$m luminosity of $M_{[4.5]}\approx-12.2$ and a $[3.6]-[4.5]$ color redder than 0.74 mag, similar to those of the prototype ILRTs SN 2008S and NGC 300 OT2008-1. Intensive monitoring of M51 with Spitzer further reveals evidence for variability of the progenitor candidate at [4.5] in the years before the OT. The progenitor is not detected in pre-outburst Hubble Space Telescope optical and near-IR images. The optical colors during outburst combined with spectroscopic temperature constraints imply a higher reddening of $E(B-V)\approx0.7$ mag and higher intrinsic luminosity of $M_r\approx-14.9$ (${\nu}L_{\nu}=5.3\times10^7~L_{\odot}$) near peak than seen in previous ILRT candidates. Moreover, the extinction estimate is higher on the rise than on the plateau, suggestive of an extended phase of circumstellar dust destruction. These results, enabled by the early discovery of M51 OT2019-1 and extensive pre-outburst archival coverage, offer new clues about the debated origins of ILRTs and may challenge the hypothesis that they arise from the electron-capture induced collapse of extreme asymptotic giant branch stars.Comment: 21 pages, 5 figures, published in ApJ

The Conundrum of Order: The Concept of Governance from an Interdisciplinary Perspective

The term governance has made an impressive career in a number of disciplines concerned with regulation, order and law. This chapter draws on insights from legal studies, sociology, political science, anthropology, history and geography to paint a multifaceted picture of existing, competing and complementing approaches to the concept of governance. For reasons of space, the chapter can but point to the different variations on a theme, as governance occupies an ambivalent place in past and present discourses on political (or, legal or economic) order and society. It is argued that beyond pointing to crucial phases of methodological and theoretical transformation within different disciplines such as the often perceived transition ‘from government to governance’, governance is itself a deeply interdisciplinary concept

Flat feline faces: is brachycephaly associated with respiratory abnormalities in the domestic cat (Felis catus)?

There has been little research into brachycephalism and associated disorders in cats. A questionnaire aimed at cat owners was used to determine the relationship between feline facial conformation and owner-reported cat management requirements and respiratory abnormalities. Owner-submitted photographs of cats were used to develop novel measures of skull conformation. One thousand valid questionnaires were received. Within these there were 373 valid photographs that allowed measurement of muzzle ratio (M%) and 494 that allowed nose position ratio (NP%). The data included 239 cats for which both measurements were available. Owners reported lifestyle factors (e.g. feeding type, grooming routine, activity level), physical characteristics (e.g. hair length) and other health characteristics of their cat (e.g. tear staining, body condition score). A composite respiratory score (RS) was calculated for each cat using their owner’s assessment of respiratory noise whilst their cat was asleep and then breathing difficulty following activity. Multivariate analyses were carried out using linear models to explore the relationship between RS and facial conformation, and lifestyle risk factors. The results showed that reductions in NP% and M% were significantly associated with RS (P < 0.001 and P = 0.026, respectively) and that the relationship was significantly negatively correlated (r = -0.56, P < 0.001 for both). Respiratory score was also significantly associated with increased presence of tear staining (P < 0.001) and a sedentary lifestyle (P = 0.01). This study improves current knowledge concerning cats with breeding-related alterations in skull confirmation and indicates that brachycephalism may have negative respiratory implications for cat health and welfare, as has been previously shown in dogs