597 research outputs found

    The Effect of Repeated Listening Experiences on Upper Elementary Students' Tolerance Toward Non-Western Music

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    vi, 107 leaves. Advisor: James CoxThis study examined the effect of repeated listening experiences on upper elementary students' tolerance toward non-western music. Intact music classes were randomly assigned to control and experimental groups. During the pretest, students indicated their degree of liking for nonwestern musical excerpts. Following the pretest, experimental subjects (n=303) received twenty-two repeated listening experiences of the same non-western examples employed on the pretest. Control subjects (n=279) received regular music in struction. Following the treatment, all subjects were administered a posttest. An analysis of covariance determined significant gain differences between groups. Overall, results indicate highly signficant (p=.05) gain differences between groups toward all styles of non-western music. Analysis by grade indicates that fourth- and fifth- grade experimental subjects significantly improved, while sixth- grade students realized positive, but insignificant gains. Analysis by genre indicates that all experimental subjects significantly increased tolerance toward African and East Indian styles, but obtained insignificant gains toward Japanese music

    Synthesis of Recursive ADT Transformations from Reusable Templates

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    Recent work has proposed a promising approach to improving scalability of program synthesis by allowing the user to supply a syntactic template that constrains the space of potential programs. Unfortunately, creating templates often requires nontrivial effort from the user, which impedes the usability of the synthesizer. We present a solution to this problem in the context of recursive transformations on algebraic data-types. Our approach relies on polymorphic synthesis constructs: a small but powerful extension to the language of syntactic templates, which makes it possible to define a program space in a concise and highly reusable manner, while at the same time retains the scalability benefits of conventional templates. This approach enables end-users to reuse predefined templates from a library for a wide variety of problems with little effort. The paper also describes a novel optimization that further improves the performance and scalability of the system. We evaluated the approach on a set of benchmarks that most notably includes desugaring functions for lambda calculus, which force the synthesizer to discover Church encodings for pairs and boolean operations

    Supermonads: one notion to bind them all

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    Several popular generalizations of monads have been implemented in Haskell. Unfortunately, because the shape of the associated type constructors do not match the standard Haskell monad interface, each such implementation provides its own type class and versions of associated library functions. Furthermore, simultaneous use of different monadic notions can be cumbersome as it in general is necessary to be explicit about which notion is used where. In this paper we introduce supermonads: an encoding of monadic notions that captures several different generalizations along with a version of the standard library of monadic functions that work uniformly with all of them. As standard Haskell type inference does not work for supermonads due to their generality, our supermonad implementation is accompanied with a language extension, in the form of a plugin for the Glasgow Haskell Compiler (GHC), that allows type inference for supermonads, obviating the need for manual annotations

    Closed Type Families with Overlapping Equations

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    Open, type-level functions are a recent innovation in Haskell that move Haskell towards the expressiveness of dependent types, while retaining the look and feel of a practical programming language. This paper shows how to increase expressiveness still further, by adding closed type functions whose equations may overlap, and may have non-linear patterns over an open type universe. Although practically useful and simple to implement, these features go be- yond conventional dependent type theory in some respects, and have a subtle metatheory

    Parsing and reflective printing, bidirectionally

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    Language designers usually need to implement parsers and printers. Despite being two intimately related programs, in practice they are often designed separately, and then need to be revised and kept consistent as the language evolves. It will be more convenient if the parser and printer can be unified and developed in one single program, with their consistency guaranteed automatically.Furthermore, in certain scenarios (like showing compiler optimisation results to the programmer), it is desirable to have a more powerful reflective printer that, when an abstract syntax tree corresponding to a piece of program text is modified, can reflect the modification to the program text while preserving layouts, comments, and syntactic sugar.To address these needs, we propose a domain-specific language BIYACC, whose programs denote both a parser and a reflective printer for an unambiguous context-free grammar. BIYACC is based on the theory of bidirectional transformations, which helps to guarantee by construction that the pairs of parsers and reflective printers generated by BIYACC are consistent. We show that BIYACC is capable of facilitating many tasks such as Pombrio and Krishnamurthi's "resugaring", simple refactoring, and language evolution.We would like to thank reviewers for their valuable comments. This work was partially supported by the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research (A) No. 25240009

    W(h)ither Fossils? Studying Morphological Character Evolution in the Age of Molecular Sequences

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    A major challenge in the post-genomics era will be to integrate molecular sequence data from extant organisms with morphological data from fossil and extant taxa into a single, coherent picture of phylogenetic relationships; only then will these phylogenetic hypotheses be effectively applied to the study of morphological character evolution. At least two analytical approaches to solving this problem have been utilized: (1) simultaneous analysis of molecular sequence and morphological data with fossil taxa included as terminals in the analysis, and (2) the molecular scaffold approach, in which morphological data are analyzed over a molecular backbone (with constraints that force extant taxa into positions suggested by sequence data). The perceived obstacles to including fossil taxa directly in simultaneous analyses of morphological and molecular sequence data with extant taxa include: (1) that fossil taxa are missing the molecular sequence portion of the character data; (2) that morphological characters might be misleading due to convergence; and (3) character weighting, specifically how and whether to weight characters in the morphological partition relative to characters in the molecular sequence data partition. The molecular scaffold has been put forward as a potential solution to at least some of these problems. Using examples of simultaneous analyses from the literature, as well as new analyses of previously published morphological and molecular sequence data matrices for extant and fossil Chiroptera (bats), we argue that the simultaneous analysis approach is superior to the molecular scaffold approach, specifically addressing the problems to which the molecular scaffold has been suggested as a solution. Finally, the application of phylogenetic hypotheses including fossil taxa (whatever their derivation) to the study of morphological character evolution is discussed, with special emphasis on scenarios in which fossil taxa are likely to be most enlightening: (1) in determining the sequence of character evolution; (2) in determining the timing of character evolution; and (3) in making inferences about the presence or absence of characteristics in fossil taxa that may not be directly observable in the fossil record. Published By: Missouri Botanical Garde

    Modularity and heterochrony in the evolution of the ceratopsian dinosaur frill

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    The fossil record provides compelling examples of heterochrony at macroevolutionary scales such as the peramorphic giant antlers of the Irish elk. Heterochrony has also been invoked in the evolution of the distinctive cranial frill of ceratopsian dinosaurs such as Triceratops. Although ceratopsian frills vary in size, shape, and ornamentation, quantitative analyses that would allow for testing hypotheses of heterochrony are lacking. Here, we use geometric morphometrics to examine frill shape variation across ceratopsian diversity and within four species preserving growth series. We then test whether the frill constitutes an evolvable module both across and within species, and compare growth trajectories of taxa with ontogenetic growth series to identify heterochronic processes. Evolution of the ceratopsian frill consisted primarily of progressive expansion of its caudal and caudolateral margins, with morphospace occupation following taxonomic groups. Although taphonomic distortion represents a complicating factor, our data support modularity both across and within species. Peramorphosis played an important role in frill evolution, with acceleration operating early in neoceratopsian evolution followed by progenesis in later diverging cornosaurian ceratopsians. Peramorphic evolution of the ceratopsian frill may have been facilitated by the decoupling of this structure from the jaw musculature, an inference that predicts an expansion of morphospace occupation and higher evolutionary rates among ceratopsids as indeed borne out by our data. However, denser sampling of the meager record of early-diverging taxa is required to test this further

    The Geology of Ukhaa Tolgod (Djadokhta Formation, Upper Cretaceous, Nemegt Basin, Mongolia)

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    The lithostratigrahy and sedimentology of the fossiliferous Upper Cretaceous strata exposed in the Gobi Desert of Mongolia at Ukhaa Tolgod are described and mapped on aerial photos. Topographic features are also mapped by plane table and alidade. Five lithologic and sedimentologic facies are described: E-1, distinctly cross-stratified sandstone with fine structure, interpreted to represent eolian dune deposits; E-2, vaguely bedded sandstone with cross-stratified concretionary sheets, interpreted to represent eolian dune deposits modified by diagenetic formation of slope-parallel concretionary sheets of pedogenic calcite; S, structureless sandstone lacking concretions or cross-strata, interpreted to represent sandslide deposits generated by mass wasting along the lee slopes; C, conglomerate interpreted to represent basin-margin conglomerates washed into the dune field from adjacent topographic highs; and M, mudstone and siltstone interpreted to represent interdune deposition in ephemeral ponds and lakes. Facies E-2 and S have not been reported previously. Eleven stratigraphic sections at various localities within the Ukhaa Tolgod drainage basin are documented. The exposed composite section consists of about 75 m of pale orange sandstones, greenish-brown conglomerates, and brown siltstones that are products of an arid environment. Four schematic cross sections are documented to illustrate the lateral relationships among the five facies. In the Ukhaa Tolgod area, the beds dip about 2.5u to the south, away from the nearby Gilbent Range. This structural attitude is interpreted to be related to the uplift of the Gilbent block along normal faults exposed at the base of the range. The dune-derived sandslides of Facies S contain a rich skeletal fauna of Late Cretaceous dinosaurs, mammals, and lizards. Essentially, all the skeletal remains collected at Ukhaa Tolgod come from Facies S. Facies E-1 does contain numerous, concave-up depressions in the cross-strata interpreted as vertebrate tracks. Facies E-2 contains abundant cylindrical structures interpreted as burrows. The strata at Ukhaa Tolgod are referred to the Djadokhta Formation. As seen in the Bayn Dzak Member at Bayn Dzak, facies E-1, E-2, S, and M dominate the lower part of the section at Ukhaa Tolgod, with prominent beds of Facies C exposed near the top. Accordingly, the exposures at Ukhaa Tolgod are referred to the Bayn Dzak Member of the Djadokhta Formation. Classic exposures of the Barun Goyot Formation at Khulsan differ in having units of flat-bedded sandstone intercalated with beds of Facies S near the top of the section. To date, over 1,000 vertebrate skulls and skeletons have been collected from Facies S. Most are preserved as float contained in small calcareous nodules; however, some were found in situ. Many specimens represent either fairly complete skulls or skulls with articulated or associated postcranial skeletons. Based on faunal similarities between Bayn Dzak and Ukhaa Tolgod, the fauna at Ukhaa Tolgod is interpreted to reflect a Campanian age. The rich assemblage of fossils makes Ukhaa Tolgod one of the richest Late Cretaceous vertebrate fossil localities in the world, and the fossils provide unique insights into evolutionary developments of mammals, lizards, and dinosaurs, including birds, less than 10 my before the terminal Cretaceous extinction event

    Parametricity and Dependent Types

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    Reynolds' abstraction theorem shows how a typing judgement in System F can be translated into a relational statement (in second order predicate logic) about inhabitants of the type. We (in second order predicate logic) about inhabitants of the type. We obtain a similar result for a single lambda calculus (a pure type system), in which terms, types and their relations are expressed. Working within a single system dispenses with the need for an interpretation layer, allowing for an unusually simple presentation. While the unification puts some constraints on the type system (which we spell out), the result applies to many interesting cases, including dependently-typed ones
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