MUSE CSP: An Extension to the Constraint Satisfaction Problem

This paper describes an extension to the constraint satisfaction problem (CSP) called MUSE CSP (MUltiply SEgmented Constraint Satisfaction Problem). This extension is especially useful for those problems which segment into multiple sets of partially shared variables. Such problems arise naturally in signal processing applications including computer vision, speech processing, and handwriting recognition. For these applications, it is often difficult to segment the data in only one way given the low-level information utilized by the segmentation algorithms. MUSE CSP can be used to compactly represent several similar instances of the constraint satisfaction problem. If multiple instances of a CSP have some common variables which have the same domains and constraints, then they can be combined into a single instance of a MUSE CSP, reducing the work required to apply the constraints. We introduce the concepts of MUSE node consistency, MUSE arc consistency, and MUSE path consistency. We then demonstrate how MUSE CSP can be used to compactly represent lexically ambiguous sentences and the multiple sentence hypotheses that are often generated by speech recognition algorithms so that grammar constraints can be used to provide parses for all syntactically correct sentences. Algorithms for MUSE arc and path consistency are provided. Finally, we discuss how to create a MUSE CSP from a set of CSPs which are labeled to indicate when the same variable is shared by more than a single CSP.Comment: See http://www.jair.org/ for any accompanying file

The Plains of Mars, European War Prints, 1500-1825

Over fifty original prints by renowned artists from the sixteenth through the early nineteenth century, including Albrecht Dürer, Lucas Cranach, Théodore Géricault, and Francisco de Goya, among many others, are featured inThe Plains of Mars: European War Prints, 1500-1825. On loan from the Sarah Campbell Blaffer Foundation at the Museum of Fine Arts, Houston, the works of art included in this exhibition examine the topics of war and peace, propaganda, heroism, brutal conflicts, and the harrowing aftermath of battle. Spanning from the Renaissance to the Romantic periods and encompassing a wide geographic scope including Italy, Germany, France, Spain, the Low Countries, England, and North America, the prints depict triumphant Renaissance soldiers, devastating scenes of violence, and satirical caricatures of political figures. Also on display is Goya’s compelling “Disasters of War” series, completed in response to the brutality of the Spanish War of Independence. Goya’s prints serve as a powerful testament to the horrors faced by both soldiers and civilians. Under the direction of Professor Felicia Else and Shannon Egan, Melissa Casale ‘19 and Bailey Harper ‘19 have researched and written didactic labels, catalogue essays, and created an interactive digital interface to complement the exhibition. Together, Melissa and Bailey will lead public tours of the exhibition. A Gallery Talk by Prof. Peter Carmichael will draw connections between the depictions of warfare on view in the Gallery with representations of the American Civil War. James Clifton, Director of the Sarah Campbell Blaffer Foundation at the Museum of Fine Arts, Houston, will be delivering a lecture in conjunction with the exhibition. Dr. Clifton, who also serves as curator of Renaissance and Baroque painting at MFAH, curated the exhibition in its first iteration and wrote the exhibition catalogue (published by Yale University Press). Dr. Clifton’s lecture not only will provide an overview of the exhibition, but also will focus on the concept of “mediated war.” A full-color catalogue with images and essays by Bailey Harper ’19 and Melissa Casale ’19, under the supervision of Profs. Felicia Else and Shannon Egan, is planned to accompany the exhibition.https://cupola.gettysburg.edu/artcatalogs/1028/thumbnail.jp

Morse matchings on polytopes

We show how to construct homology bases for certain CW complexes in terms of discrete Morse theory and cellular homology. We apply this technique to study certain subcomplexes of the half cube polytope studied in previous works. This involves constructing explicit complete acyclic Morse matchings on the face lattice of the half cube; this procedure may be of independent interest for other highly symmetric polytopes

The MMT API: A Generic MKM System

The MMT language has been developed as a scalable representation and interchange language for formal mathematical knowledge. It permits natural representations of the syntax and semantics of virtually all declarative languages while making MMT-based MKM services easy to implement. It is foundationally unconstrained and can be instantiated with specific formal languages. The MMT API implements the MMT language along with multiple backends for persistent storage and frontends for machine and user access. Moreover, it implements a wide variety of MMT-based knowledge management services. The API and all services are generic and can be applied to any language represented in MMT. A plugin interface permits injecting syntactic and semantic idiosyncrasies of individual formal languages.Comment: Conferences on Intelligent Computer Mathematics (CICM) 2013 The final publication is available at http://link.springer.com

Propagation of the First Flames in Type Ia Supernovae

We consider the competition of the different physical processes that can affect the evolution of a flame bubble in a Type Ia supernovae -- burning, turbulence and buoyancy. Even in the vigorously turbulent conditions of a convecting white dwarf, thermonuclear burning that begins at a point near the center (within 100 km) of the star is dominated by the spherical laminar expansion of the flame, until the burning region reaches kilometers in size. Consequently flames that ignite in the inner ~20 km promptly burn through the center, and flame bubbles anywhere must grow quite large--indeed, resolvable by large-scale simulations of the global system--for significant motion or deformation occur. As a result, any hot-spot that successfully ignites into a flame can burn a significant amount of white dwarf material. This potentially increases the stochastic nature of the explosion compared to a scenario where a simmering progenitor can have small early hot-spots float harmlessly away. Further, the size where the laminar flame speed dominates other relevant velocities sets a characteristic scale for fragmentation of larger flame structures, as nothing--by definition--can easily break the burning region into smaller volumes. This makes possible the development of semi-analytic descriptions of the earliest phase of the propagation of burning in a Type Ia supernovae, which we present here. Our analysis is supported by fully resolved numerical simulations of flame bubbles.Comment: 33 pages, 14 figures, accepted for publication in Ap

Chromatic transit light curves of disintegrating rocky planets

Context. Kepler observations have revealed a class of short period exoplanets, of which Kepler-1520 b is the prototype, which have comet-like dust tails thought to be the result of small, rocky planets losing mass. The shape and chromaticity of the transits constrain the properties of the dust particles originating from the planet's surface, offering a unique opportunity to probe the composition and geophysics of rocky exoplanets. Aims. We aim to approximate the average Kepler long-cadence light curve of Kepler-1520 b and investigate how the optical thickness and transit cross-section of a general dust tail can affect the observed wavelength dependence and depth of transit light curves. Methods. We developed a new 3D model that ejects sublimating particles from the planet surface to build up a dust tail, assuming it to be optically thin, and used 3D radiative transfer computations that fully treat scattering using the distribution of hollow spheres (DHS) method, to generate transit light curves between 0.45 and 2.5 $\mu$m. Results. We show that the transit depth is wavelength independent for optically thick tails, potentially explaining why only some observations indicate a wavelength dependence. From the 3D nature of our simulated tails, we show that their transit cross-sections are related to the component of particle ejection velocity perpendicular to the planet's orbital plane and use this to derive a minimum ejection velocity of 1.2 kms$^{-1}$. To fit the average transit depth of Kepler-1520 b of 0.87%, we require a high dust mas-loss rate of 7 $-$ 80 M$_\oplus$ Gyr$^{-1}$ which implies planet lifetimes that may be inconsistent with the observed sample. Therefore, these mass-loss rates should be considered to be upper limits.Comment: 22 pages, 22 figures, accepted for publication in A&

The Cerebellum and SIDS: Disordered Breathing in a Mouse Model of Developmental Cerebellar Purkinje Cell Loss during Recovery from Hypercarbia.

The cerebellum assists coordination of somatomotor, respiratory, and autonomic actions. Purkinje cell alterations or loss appear in sudden infant death and sudden death in epilepsy victims, possibly contributing to the fatal event. We evaluated breathing patterns in 12 wild-type (WT) and Lurcher mutant mice with 100% developmental cerebellar Purkinje cell loss under baseline (room air), and recovery from hypercapnia, a concern in sudden death events. Six mutant and six WT mice were exposed to 4-min blocks of increasing CO2 (2, 4, 6, and 8%), separated by 4-min recovery intervals in room air. Breath-by-breath patterns, including depth of breathing and end-expiratory pause (EEP) durations during recovery, were recorded. No baseline genotypic differences emerged. However, during recovery, EEP durations significantly lengthened in mutants, compared to WT mice, following the relatively low levels of CO2 exposure. Additionally, mutant mice exhibited signs of post-sigh disordered breathing during recovery following each exposure. Developmental cerebellar Purkinje cell loss significantly affects compensatory breathing patterns following mild CO2 exposure, possibly by inhibiting recovery from elevated CO2. These data implicate cerebellar Purkinje cells in the ability to recover from hypercarbia, suggesting that neuropathologic changes or loss of these cells contribute to inadequate ventilatory recovery to increased environmental CO2. Multiple disorders, including sudden infant death syndrome (SIDS) and sudden unexpected death in epilepsy (SUDEP), appear to involve both cardiorespiratory failure and loss or injury to cerebellar Purkinje cells; the findings support the concept that such neuropathology may precede and exert a prominent role in these fatal events

Fish oil (n-3 fatty acids) in drug resistant epilepsy: a randomised placebo-controlled crossover study.

Backgroundn-3 fatty acids inhibit neuronal excitability and reduce seizures in animal models. High-dose fish oil has been explored in two randomised trials in drug resistant epilepsy with negative results. We performed a phase II randomised controlled crossover trial of low-dose and high-dose fish oil in participants with drug resistant epilepsy to explore whether low-dose or high-dose fish oil reduces seizures or improves cardiovascular health.MethodsRandomised placebo-controlled trial of low-dose and high-dose fish oil versus placebo (corn oil, linoleic acid) in 24 participants with drug resistant epilepsy. A three-period crossover design was utilised lasting 42 weeks, with three 10-week treatment periods and two 6-week washout periods. All participants were randomised in double-blind fashion to receive placebo, high dose or low dose in different sequences. The primary outcome was per cent change in total seizure frequency.FindingsLow-dose fish oil (3 capsules/day, 1080 mg eicosapentaenoic acid+docosahexaenoic acid) was associated with a 33.6% reduction in seizure frequency compared with placebo. Low-dose fish oil was also associated with a mild but significant reduction in blood pressure. High-dose fish oil was no different than placebo in reducing seizures or improving cardiac risk factors.InterpretationIn this phase II randomised crossover trial, low-dose fish oil was effective in reducing seizures compared with placebo. The magnitude of improvement is similar to that of recent antiepileptic drug trials in drug resistant epilepsy (DRE). The results indicate that low-dose fish oil may reduce seizures and improve the health of people with epilepsy. These findings justify a large multicentre randomised trial of low-dose fish oil (n-3 fatty acids <1080 mg/day) in drug resistant epilepsy.Trial registration numberNCT00871377