Denotational semantics with nominal scott domains

When defining computations over syntax as data, one often runs into tedious issues concerning α -equivalence and semantically correct manipulations of binding constructs. Here we study a semantic framework in which these issues can be dealt with automatically by the programming language. We take the user-friendly “nominal” approach in which bound objects are named. In particular, we develop a version of Scott domains within nominal sets and define two programming languages whose denotational semantics are based on those domains. The first language, λν -PCF, is an extension of Plotkin’s PCF with names that can be swapped, tested for equality and locally scoped; although simple, it already exposes most of the semantic subtleties of our approach. The second language, PNA, extends the first with name abstraction and concretion so that it can be used for metaprogramming over syntax with binders. For both languages, we prove a full abstraction result for nominal Scott domains analogous to Plotkin’s classic result about PCF and conventional Scott domains: two program phrases have the same observable operational behaviour in all contexts if and only if they denote equal elements of the nominal Scott domain model. This is the first full abstraction result we know of for languages combining higher-order functions with some form of locally scoped names which uses a domain theory based on ordinary extensional functions, rather than using the more intensional approach of game semantics. To obtain full abstraction, we need to add two functionals, one for existential quantification over names and one for “definite description” over names. Only adding one of them is not enough, as we give counter-examples to full abstraction in both cases.This work is supported by a Gates Cambridge Scholarship and the ERC Advanced Grant Events, Causality and Symmetry (ECSYM)This version is the author accepted manuscript. The final version is available from ACM at http://dl.acm.org/citation.cfm?id=2629529

Implementación de técnica de cultivo para la investigación de Legionella pneumophila en depósitos domiciliarios de agua potable en Resistencia, Chaco

Legionella pneumophila es una bacteria ambiental capaz de sobrevivir en un amplio intervalo de condiciones físico-químicas y de colonizar los sistemas de distribución y almacenamiento del agua potable. Es el principal patógeno trasmitido por el agua que produce el 90% de los casos de legionelosis. El objetivo del trabajo fue realizar la puesta a punto de la técnica por cultivo para la vigilancia de L. pneumophila en depósitos domiciliarios de agua potable acorde con la normativa internacional. En las muestras de agua analizadas no se obtuvo desarrollo de L. pneumophila; la cepa utilizada como control positivo, permitió constatar la aptitud de los medios utilizados para la detección de este patógeno en las muestras de agua. La vigilancia de este microorganismo en el agua de consumo humano representa el primer paso en pos de abordar el control de su diseminación hacia huéspedes susceptibles

Early medieval Italian Alps: reconstructing diet and mobility in the valleys

In Early Middle Ages (sixth\u2013eleventh centuries AD), South Tyrol (Italian Alps) played a key role for geographical and military reasons. Historical sources document that allochthonous groups (germani) entered the territory, and the material culture shows mutual cultural exchanges between autochthonous and germani. Besides the nature of the migration, the demographic and socio-cultural impacts on the local population are still unknown. Stable isotope analyses were performed to provide insights into dietary patterns, subsistence strategies, changes in socio-economic structures, and mobility, according to spatial (e.g. valleys, altitudes) and chronological (centuries) parameters. Bone collagen of 32 faunal and 91 human bone samples from nine sites, located at different altitudes, was extracted for stable carbon, nitrogen, and sulphur isotope analyses. In total, 94% (30/32) of the faunal remains were of good quality, while the humans displayed 93% (85/91) of good quality samples for \u3b413C and \u3b415N and 44% (40/91) for \u3b434S stable isotopes. The isotopic results of the animals reflected a terrestrial-based diet. Statistical differences were observed within and among the humans of the different valleys. The \u3b413C values of individuals sampled from higher altitudes indicated a mainly C3 plant-based diet compared to areas at lower altitudes, where more positive \u3b413C values showed an intake of C4 plants. The \u3b415N values suggested a terrestrial-based diet with a greater consumption of animal proteins at higher altitudes. The data revealed higher variability in \u3b434S values in the Adige valley, with individuals probably migrating and/or changing dietary habits

The application of different 3D-scan-systems and photogrammetry at an excavation — A Neolithic dolmen from Switzerland

The discovery of a Neolithic dolmen in Switzerland with inhumations, dating between 3500 and 3000 BCE, was an exceptional finding. To provide best conditions for subsequent studies on the archaeological remains our interdisciplinary team decided to apply 3D documentation. Depending on different factors, two scanning systems with four scanners and photogrammetry were applied and the obtained data was combined. Detailed excavation plans and simultaneously a reduction of excavation time without loss of information were the result. A virtual animation of the dolmen in its reconstructed ancient appearance combined with the context of the grave goods was created. The 3D documentation provided initial data for anthropological and paleogenetic analyses. The individuals buried in the dolmen might provide novel information to the Neolithic research of central Europe. Additionally, with the help of the 3D data, the dolmen was rebuilt to make this archaeological heritage accessible to the public

The well-preserved Late Neolithic dolmen burial of Oberbipp, Switzerland. Construction, use, and post-depositional processes

Excavation of the Late Neolithic dolmen of Oberbipp BE, Steingasse in the Swiss Central Plateau provided a unique opportunity for a comprehensive study of the archaeological and anthropological evidence. In multidisciplinary studies, we investigated the processes at work during construction, use, and abandonment of the megalithic structure, as well as the dietary habits, subsistence strategy, and possible mobility of the Neolithic population. Archaeological methods included micromorphology, archaeobiology, typology, use-wear analysis, and geology. The anthropological investigation was complemented by an analysis of stable isotope ratios and palaeogenetics. Local topography and the cover of alluvial sediments ensured an extraordinary conservation of the monument. It allowed the preservation of the human remains of at least 42 individuals of both sexes and all ages. The observation of the sedimentary and post-depositional processes, supplemented by an extensive series of radiocarbon dates, allowed us to reconstruct the history of the dolmen in its environment and the definition of at least two deposition phases. We found genetic evidence of lactase intolerance, a local population with a mixed ancestry of early Anatolian farmers and Western hunter-gatherers, and a crop-based diet. Sparse remains of a nearby Late Neolithic settlement sustain the interpretation that this is the burial site of a local farming community. Evidence of higher mobility of females and kinship over three generations solely in the paternal line suggests a virilocal community. Bone-altering pathologies support the assumption of a caring society

Mutation detection analysis of a region of 16S-like ribosomal RNA gene of Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii

<p>Abstract</p> <p>Background</p> <p>The level of intra-species genetic variation in <it>Entamoeba histolytica, Entamoeba dispar </it>and <it>Entamoeba moshkovskii </it>populations in a localized geographic area, like Puducherry, India, remains unknown.</p> <p>Methods</p> <p>In the present study the existence of genetic variation in the nested multiplex polymerase chain reaction (NM-PCR) amplified region of the 16S-like ribosomal RNA genes of <it>E. histolytica, E. dispar </it>and <it>E. moshkovskii </it>was investigated by riboprinting and single strand conformation polymorphism (SSCP) analysis.</p> <p>Results</p> <p>We found that 70 stool specimens were positive for <it>E. histolytica</it>, 171 stool specimens were positive for <it>E. dispar</it>, and 37 stool specimens were positive for <it>E. moshkovskii </it>by NM-PCR. Ninety liver abscess pus specimens, 21 urine specimens, and 8 saliva specimens were positive for <it>E. histolytica </it>by NM-PCR. Riboprinting analysis detected a mutation in the PCR product of only one <it>E. histolytica </it>isolate from a stool specimen. However, SSCP analysis detected mutations in the PCR products of five <it>E. histolytica </it>isolates and three <it>E. moshkovskii </it>isolates from stool specimens, and one <it>E. histolytica </it>isolate from a saliva specimen. The mutations detected by riboprinting and SSCP analysis were confirmed by sequencing. All the nucleotide sequences showing mutations in this study have already been deposited into the NCBI GenBank database under accession numbers [GenBank: <ext-link ext-link-type="gen" ext-link-id="EF682200">EF682200</ext-link> to GenBank: <ext-link ext-link-type="gen" ext-link-id="EF682208">EF682208</ext-link>].</p> <p>Conclusion</p> <p>The present study has revealed the subsistence of mutations in the ribosomal RNA genes of <it>E. histolytica </it>and <it>E. moshkovskii</it>, which points towards the existence of intra-species genetic variation in <it>E. histolytica </it>and <it>E. moshkovskii </it>isolates infecting humans.</p

Modelling Hierarchy and Specialization of a System of Cities from an Evolutionary Perspective on Firms' Interactions

Despite their great diversity, most systems of cities show remarkably similar patterns when comparing the size distribution and the economic specialization of their constitutive cities. The universality of these patterns sparked the interest of geographers, economists and physicists. However, until now, no economic model has relied on a micro-based and evolutionary approach to reproduce these regularities. In this chapter, we intend to fill this gap by proposing a model where the micro dynamics of localized firms generate the two macro regularities of size distribution and economic specialization. The model is based on boundedly rational firms’ competition and path dependent innovation. We discuss the possible emergence of macro properties from these micro behaviors of firms