Mercury's geochronology revised by applying Model Production Functions to Mariner 10 data: geological implications

Model Production Function chronology uses dynamic models of the Main Belt Asteroids (MBAs) and Near Earth Objects (NEOs) to derive the impactor flux to a target body. This is converted into the crater size-frequency-distribution for a specific planetary surface, and calibrated using the radiometric ages of different regions of the Moon's surface. This new approach has been applied to the crater counts on Mariner 10 images of the highlands and of several large impact basins on Mercury. MPF estimates for the plains show younger ages than those of previous chronologies. Assuming a variable uppermost layering of the Hermean crust, the age of the Caloris interior plains may be as young as 3.59 Ga, in agreement with MESSENGER results that imply that long-term volcanism overcame contractional tectonics. The MPF chronology also suggests a variable projectile flux through time, coherent with the MBAs for ancient periods and then gradually comparable also to the NEOs.Comment: Accepted by Journal Geophysical Research Letter

Dynamic Package Interfaces - Extended Version

A hallmark of object-oriented programming is the ability to perform computation through a set of interacting objects. A common manifestation of this style is the notion of a package, which groups a set of commonly used classes together. A challenge in using a package is to ensure that a client follows the implicit protocol of the package when calling its methods. Violations of the protocol can cause a runtime error or latent invariant violations. These protocols can extend across different, potentially unboundedly many, objects, and are specified informally in the documentation. As a result, ensuring that a client does not violate the protocol is hard. We introduce dynamic package interfaces (DPI), a formalism to explicitly capture the protocol of a package. The DPI of a package is a finite set of rules that together specify how any set of interacting objects of the package can evolve through method calls and under what conditions an error can happen. We have developed a dynamic tool that automatically computes an approximation of the DPI of a package, given a set of abstraction predicates. A key property of DPI is that the unbounded number of configurations of objects of a package are summarized finitely in an abstract domain. This uses the observation that many packages behave monotonically: the semantics of a method call over a configuration does not essentially change if more objects are added to the configuration. We have exploited monotonicity and have devised heuristics to obtain succinct yet general DPIs. We have used our tool to compute DPIs for several commonly used Java packages with complex protocols, such as JDBC, HashSet, and ArrayList.Comment: The only changes compared to v1 are improvements to the Abstract and Introductio

Euler Integration of Gaussian Random Fields and Persistent Homology

In this paper we extend the notion of the Euler characteristic to persistent homology and give the relationship between the Euler integral of a function and the Euler characteristic of the function's persistent homology. We then proceed to compute the expected Euler integral of a Gaussian random field using the Gaussian kinematic formula and obtain a simple closed form expression. This results in the first explicitly computable mean of a quantitative descriptor for the persistent homology of a Gaussian random field.Comment: 21 pages, 1 figur

Theater percussion: developing a twenty-first-century genre through the connection of visual, dramatic, and percussive arts

Theater percussion, as it shall be referred to for the purpose of this dissertation, is an existing, yet unnamed, genre characterized by a systematic approach of combining percussion with extra-musical components that tap into senses or aspects of sentiment - visually, aurally, and emotionally, and are made possible with the use of compositional additives - acting, movement, text, and multimedia avenues such as audio and video. To complete the process, these extra-musical elements are combined with the main musical influence - a composition for percussion ensemble or soloist. Several pieces in this style have and continue to be performed by ensembles around the world, although I will be focusing on three works that fit perfectly to the theater percussion archetype. These are Living Room Music by John Cage, ?Corporel by Vinko Globokar, and Alice on Time written by myself. Through research of this style it can be determined that theater percussion is a common compositional technique. However, without a name or direct affiliation to any one musical genre, its current status provides a vague, cross-categorization of compositional species, and is at risk of becoming an extinct performance art subgenre. In addition to investigating its place in music history, the process of naming and defining serve to provide a richer understanding of this style and will ideally result in a renewed and enhanced interest from performers and audiences alike

Analysis of F and G Subdwarfs. I. The Location of Subdwarfs in the Theoretical H-R Diagram

Spectrum scans and model stellar atmospheres have been used to locate in the (L/L_⊙, T_(eff)) plane F and G subdwarfs having known parallax A comparison is made between their position on the H-R diagram and the evolutionary tracks for Population II models of low- and high-helium content recently computed by Faulkner and Iben. The lower helium-content models are found to give somewhat more plausible ages than the high-helium models. Nevertheless, for both the low- and high-helium-content models, we find several subdwarfs with ages apparently greater than 10 X 10^9 years

Gallium(III)-Promoted Halocyclizations of 1,6-Diynes

Adrian Landreth was an REU student, summer 2014Cyclization of 1,6-diynes promoted by stoichiometric Ga(III) halides produces vinyl halides in good to excellent yields. Under acidic conditions, initially formed iodocyclization products undergo in situ Friedel-Crafts cyclizations, giving access to iodo-indenopyridines. The application of the vinyl halides in cross-coupling reactions has been explored, and mechanistic aspects of the cyclization are discussed.HIGMS CMLD Initiative (P50 GM067041) NSF REU - Adrian Landreth support (CHE 1156666) NSF - NMR purchase (CHE 0619339) NSF - HRMS purchase (CHE0443618

PhEMaterialism: Response-able Research & Activism

This Special Issue offers PhEmaterialisms as a way to explore the world asvital and complex, while simultaneously being response-able to the multiple ethical imperatives of late-stage capitalism. We argue that PhEmaterialist thinking and practices can help us grapple with growing educational complexities, enabling strategies toresist and create alternatives to the patterns of injustice occurring across the world, from burgeoning ethno-nationalist and neo-fascist political movements, to rising global poverty levels, to massive population displacements, to environmental degradation, to toxic internet movements grounded in misogyny, homophobia, transphobia, and xenophobia (Strom & Martin, 2017a). To understand, enquire into, and generate action worthy of the complexity of our times requires a fundamental shift in our thinking and research practice. This shift disrupts the foundational logic on which dominant thinking in education (and indeed, all Western society) is based—humanism and anthropocentrism (Braidotti, 2013; Murris, 2016; Snaza et al, 2014). Instead, we argue that we need to put theories/concepts to work in education and educational research which can better account for the multiple, entangled, ever-shifting, difference-rich nature of processes of teaching, learning, schooling, and activism. For this work, we also draw on a rich feminist legacy attentive to unequal power relations (e.g., Ahmed, 1998; Anzaldua, 1999; hooks, 1994; Spivak, 1978), and our critical approach to rethinking Vitruvian “man” is especially informed by posthuman/new materialist feminist thinkings and thinkers, including Rosi Braidotti, Donna Haraway, and Karen Barad