An existential crisis resolved: type inference for first-class existential types

Despite the great success of inferring and programming with universal types, their dual—existential types—are much harder to work with. Existential types are useful in building abstract types, working with indexed types, and providing first-class support for refinement types. This paper, set in the context of Haskell, presents a bidirectional type-inference algorithm that infers where to introduce and eliminate existentials without any annotations in terms, along with an explicitly typed, type-safe core language usable as a compilation target. This approach is backward compatible. The key ingredient is to use strong existentials, which support (lazily) projecting out the encapsulated data, not weak existentials accessible only by pattern-matching.

Identifikasi Jenis-jenis Herpetofauna di Taman Wisata Alam Gunung Permisan, Bangka Selatan, Provinsi Kepulauan Bangka Belitung

Abstract[Types of Herpetofauna Identification in the Gunung Permisan Nature Park, South Bangka, Bangka Belitung Islands Province]. The Nature Tourism Park, Gunung Permisan is a conservation area located in Permis Village, South Bangka Regency. This study was conducted to identify the types of herpetofauna diversity in Gunung Permisan. Herpetofauna are including reptile and amphibian classes, that played an important role in maintaining the balance and sustainability of the ecosystem. The research method was using the exploration and Visual Encounter Survey. The type of herpetofauna was identified by observing the morphological differences. A total of 7 species consist of 5 species of the Amphibians and 2 species of the Reptiles have been collected from the research. These 7 species consist of two order Anura and Squamata. Anura has 2 families, including: Dicroglossidae and Ranidae. Squamata has 2 families, including Viperidae and Scincidae. The diversity of herpetofauna in the Gunung Permisan was medium category. Keywords: Gunung Permisan; Herpetofauna; Amphibian; Reptile.ABSTRAKTaman Wisata Alam Gunung Permisan merupakan wilayah konservasi yang berada di Desa Permis, Kabupaten Bangka Selatan. Penelitian ini dilakukan untuk mengidentifikasi jenis keanekaragaman herpetofauna di Kawasan Gunung Permisan. Herpetofauna meliputi kelas reptil dan amfibi berperan penting dalam menjaga keseimbangan dan keberlangsungan ekosistem kawasan tersebut. Metode pengumpulan data menggunakan metode eksplorasi dan survey perjumpaan visual/VES. Identifikasi jenis herpetofauna dengan cara mengamati perbedaan morfologinya. Berdasarkan penelitian yang telah dilakukan ada sebanyak 7 spesies herpetofauna yang ditemukan, meliputi 5 jenis spesies dari kelas Amphibi dan 2 jenis spesies dari kelas Reptil. Tujuh spesies ini terdiri atas ordo Anura dan Squamata. Ordo Anura terdapat 2 famili yaitu famili Dicroglossidae dan Ranidae. Ordo Squamata terdapat 2 famili yaitu famili Viperidae dan Scincidae. Keanekaragaman herpetofauna di Kawasan Gunung Permisan termasuk ke dalam golongan sedang.Kata kunci: Gunung Permisan; Herpetofauna; Amfibi; Reptil.

Identifikasi Jenis-jenis Herpetofauna di Taman Wisata Alam Gunung Permisan, Bangka Selatan, Provinsi Kepulauan Bangka Belitung

Abstract[Types of Herpetofauna Identification in the Gunung Permisan Nature Park, South Bangka, Bangka Belitung Islands Province]. The Nature Tourism Park, Gunung Permisan is a conservation area located in Permis Village, South Bangka Regency. This study was conducted to identify the types of herpetofauna diversity in Gunung Permisan. Herpetofauna are including reptile and amphibian classes, that played an important role in maintaining the balance and sustainability of the ecosystem. The research method was using the exploration and Visual Encounter Survey. The type of herpetofauna was identified by observing the morphological differences. A total of 7 species consist of 5 species of the Amphibians and 2 species of the Reptiles have been collected from the research. These 7 species consist of two order Anura and Squamata. Anura has 2 families, including: Dicroglossidae and Ranidae. Squamata has 2 families, including Viperidae and Scincidae. The diversity of herpetofauna in the Gunung Permisan was medium category. Keywords: Gunung Permisan; Herpetofauna; Amphibian; Reptile.ABSTRAKTaman Wisata Alam Gunung Permisan merupakan wilayah konservasi yang berada di Desa Permis, Kabupaten Bangka Selatan. Penelitian ini dilakukan untuk mengidentifikasi jenis keanekaragaman herpetofauna di Kawasan Gunung Permisan. Herpetofauna meliputi kelas reptil dan amfibi berperan penting dalam menjaga keseimbangan dan keberlangsungan ekosistem kawasan tersebut. Metode pengumpulan data menggunakan metode eksplorasi dan survey perjumpaan visual/VES. Identifikasi jenis herpetofauna dengan cara mengamati perbedaan morfologinya. Berdasarkan penelitian yang telah dilakukan ada sebanyak 7 spesies herpetofauna yang ditemukan, meliputi 5 jenis spesies dari kelas Amphibi dan 2 jenis spesies dari kelas Reptil. Tujuh spesies ini terdiri atas ordo Anura dan Squamata. Ordo Anura terdapat 2 famili yaitu famili Dicroglossidae dan Ranidae. Ordo Squamata terdapat 2 famili yaitu famili Viperidae dan Scincidae. Keanekaragaman herpetofauna di Kawasan Gunung Permisan termasuk ke dalam golongan sedang.Kata kunci: Gunung Permisan; Herpetofauna; Amfibi; Reptil.

Object-oriented programming

The object-oriented approach to programming and design is characterized by its focus on the data structures of a program rather than the procedures. Often, invoking a procedure with a data object as its principal argument is thought of as ‘sending a message’ to the object. Special language support is typically available for collecting these procedures (sometimes known as ‘methods’) together with the definition of the type of the object. This approach is supported in Fortran by type extension, polymorphic variables, type-bound procedures, abstract types, and finalization.

From Monuments to Miniatures: Emergence of Stamps and Related Image-bearing Objects during the Neolithic

In southwest Asia, the emphasis on architecture and burial ritual, which was instrumental in the construction of place-bound identities during the Early Neolithic (c. 10,000–7000 cal. bc), shifted toward an emphasis on miniature portable objects, such as figurines, stamps and ceramics, during the Later Neolithic (c. 7000–5000 cal. bc). Through a focus on stamps, this article argues that the appearance and proliferation of image-bearing portable objects is related to a new understanding of identities around emergent concepts of ‘house’ and ‘community’, which reordered the terms of social affiliation as well as difference and hierarchy at various scales. In terms of an iconographical approach, stamp imagery shows some affinities with the anthropomorphic and zoomorphic themes of the Early Neolithic; however, the majority of the Later Neolithic stamp imagery is composed of highly abstract types that cannot immediately be associated with the themes of the Early Neolithic. A close examination would indicate that these abstract types were also reproduced by manipulating ancestral imagery. It would also appear that certain types of images were employed on certain types of objects, such as ceramics and figurines, in increasingly structured ways. Arguably, these seemingly different object classes are an outcome of a seamless historical discourse of raw materials, images and forms, continuously shifting the conceptualization of self and society. It is in this context that stamps may be treated as figurines of a highly abstract, highly crafted and highly standardized nature. While the clay figurines appropriated social identities in the domestic sphere, stamps and ceramics were instrumental in linking multiple scales of identity formation, from personal to communal. Reconsidering the material shift from the Early to Late Neolithic, I suggest that the spreading regulation of appropriating body and food was central in the construction of a convergent politics of reproduction around the concepts of ‘house’.

Bartók’s Viola Concerto manuscript: Some questions and speculations

The question of authenticity in the creation of Bartók’s Viola Concerto has been one of the most enigmatic in the viola repertoire. Inconsistencies among revisions of the work by different scholars since the first attempt by Tibor Serly in 1946 reveal that the task of uncovering an authentic final version by scrutinizing the manuscript itself is not always a clearcut or “purely mechanical” endeavor. Following a brief overview of the manuscript’s layout, this article addresses some ambiguous details based on a number of puzzling indications. Some of these questions can only be resolved by acquiring an in-depth knowledge of Bartók’s musical language. The manuscript draft is thereby approached not only by studying the primary-source materials alone, but also by means of a theoretic-analytical approach. The latter takes into account principles of modality, polymodal combination, and more abstract types of pitch sets, such as hybrid modes, the octatonic scale, and other more chromatic configurations. General types of scalar or modal construction are discussed as basic determinants in performing certain figural details. Such principles as diatonic expansion, chromatic compression, and polymodal chromaticism are shown, for instance, to be essential for understanding the content and function of the trill figures and the larger linear constructions to which they belong. Thus, we may assume that the combined levels of research and analysis suggested above are essential in arriving at Bartók’s authentic conception.