3,601 research outputs found

    Endurant Types in Ontology-Driven Conceptual Modeling: Towards OntoUML 2.0

    Get PDF
    For over a decade now, a community of researchers has contributed to the development of the Unified Foundational Ontology (UFO) - aimed at providing foundations for all major conceptual modeling constructs. This ontology has led to the development of an Ontology-Driven Conceptual Modeling language dubbed OntoUML, reflecting the ontological micro-theories comprising UFO. Over the years, UFO and OntoUML have been successfully employed in a number of academic, industrial and governmental settings to create conceptual models in a variety of different domains. These experiences have pointed out to opportunities of improvement not only to the language itself but also to its underlying theory. In this paper, we take the first step in that direction by revising the theory of types in UFO in response to empirical evidence. The new version of this theory shows that many of the meta-types present in OntoUML (differentiating Kinds, Roles, Phases, Mixins, etc.) should be considered not as restricted to Substantial types but instead should be applied to model Endurant Types in general, including Relator types, Quality types and Mode types. We also contribute a formal characterization of this fragment of the theory, which is then used to advance a metamodel for OntoUML 2.0. Finally, we propose a computational support tool implementing this updated metamodel

    Precise determination of muon and electromagnetic shower contents from shower universality property

    Full text link
    We consider two new aspects of Extensive Air Shower development universality allowing to make accurate estimation of muon and electromagnetic (EM) shower contents in two independent ways. In the first case, to get muon (or EM) signal in water Cherenkov tanks or in scintillator detectors it is enough to know the vertical depth of shower maximum and the total signal in the ground detector. In the second case, the EM signal can be calculated from the primary particle energy and the zenith angle. In both cases the parametrizations of muon and EM signals are almost independent on primary particle nature, energy and zenith angle. Implications of the considered properties for mass composition and hadronic interaction studies are briefly discussed. The present study is performed on 28000 of proton, oxygen and iron showers, generated with CORSIKA 6.735 for E1E^{-1} spectrum in the energy range log(E/eV)=18.5-20.0 and uniformly distributed in cos^2(theta) in zenith angle interval theta=0-65 degrees for QGSJET II/Fluka interaction models.Comment: Submitted to Phys. Rev.

    A new multiparametric topological method for determining the primary cosmic ray mass composition in the knee energy region

    Full text link
    The determination of the primary cosmic ray mass composition from the characteristics of extensive air showers (EAS), obtained at an observation level in the lower half of the atmosphere, is still an open problem. In this work we propose a new method of the Multiparametric Topological Analysis and show its applicability for the determination of the mass composition of the primary cosmic rays at the PeV energy region.Comment: 8 pages, 4 figures, talk given at Vulcano 2004 Workshop 'Frontier Objects in Physics and Astrophysics', Vulcano, Italy, 24-29.05.04, to be published in the Proceedings of the Worksho

    Lizards as model organisms of sex chromosome evolution: What we really know from a systematic distribution of available data?

    Get PDF
    Lizards represent unique model organisms in the study of sex determination and sex chromosome evolution. Among tetrapods, they are characterized by an unparalleled diversity of sex determination systems, including temperature-dependent sex determination (TSD) and genetic sex determination (GSD) under either male or female heterogamety. Sex chromosome systems are also extremely variable in lizards. They include simple (XY and ZW) and multiple (X1X2Y and Z1Z2W) sex chromosome systems and encompass all the different hypothesized stages of diversification of heterogametic chromosomes, from homomorphic to heteromorphic and completely heterochromatic sex chromosomes. The co-occurrence of TSD, GSD and different sex chromosome systems also characterizes different lizard taxa, which represent ideal models to study the emergence and the evolutionary drivers of sex reversal and sex chromosome turnover. In this review, we present a synthesis of general genome and karyotype features of non-snakes squamates and discuss the main theories and evidences on the evolution and diversification of their different sex determination and sex chromosome systems. We here provide a systematic assessment of the available data on lizard sex chromosome systems and an overview of the main cytogenetic and molecular methods used for their identification, using a qualitative and quantitative approach

    Comparative cytogenetics on eight Malagasy Mantellinae (Anura, Mantellidae) and a synthesis of the karyological data on the subfamily

    Get PDF
    We performed a molecular and cytogenetic analysis on different Mantellinae species and revised the available chromosomal data on this group to provide an updated assessment of its karyological diver sity and evolution. Using a fragment of the mitochondrial 16S rRNA, we performed a molecular taxo nomic identification of the samples that were used for cytogenetic analyses. A comparative cytogenetic analysis, with Giemsa’s staining, Ag-NOR staining and sequential C-banding + Giemsa + CMA + DAPI was performed on eight species: Gephyromantis sp. Ca19, G. striatus (Vences, Glaw, Andreone, Jesu et Schimmenti, 2002), Mantidactylus (Chonomantis) sp. Ca11, M. (Brygoomantis) alutus (Peracca, 1893), M. (Hylobatrachus) cowanii (Boulenger, 1882), Spinomantis prope aglavei “North” (Methuen et Hewitt, 1913), S. phantasticus (Glaw et Vences, 1997) and S. sp. Ca3. Gephyromantis striatus, M. (Brygoomantis) alutus and Spinomantis prope aglavei “North” have a karyotype of 2n = 24 chromosomes while the other species show 2n = 26 chromosomes. Among the analysed species we detected differences in the number and position of telocentric elements, location of NOR loci (alternatively on the 6th, 7th or 10th pair) and in the distribution of heterochromatin, which shows species-specific patterns. Merging our data with those previously available, we propose a karyotype of 2n = 26 with all biarmed elements and loci of NORs on the 6th chromosome pair as the ancestral state in the whole family Mantellidae. From this putative ancestral condition, a reduction of chromosome number through similar tandem fusions (from 2n = 26 to 2n = 24) occurred independently in Mantidactylus Boulenger, 1895 (subgenus Brygoomantis Dubois, 1992), Spinomantis Dubois, 1992 and Gephyromantis Methuen, 1920. Similarly, a relocation of NORs, from the putative primitive configuration on the 6th chromosome, occurred independently in Gephyroman tis, Blommersia Dubois, 1992, Guibemantis Dubois, 1992, Mantella Boulenger, 1882 and Spinomantis. Chromosome inversions of primitive biarmed elements likely generated a variable number of telocentric elements in Mantella nigricans Guibé, 1978 and a different number of taxa of Gephyromantis (subgenera Duboimantis Glaw et Vences, 2006 and Laurentomantis Dubois, 1980) and Mantidactylus (subgenera Brygoomantis, Chonomantis Glaw et Vences, 1994, Hylobatrachus Laurent, 1943 and Ochthomantis Glaw et Vences, 1994)

    Comparative cytogenetics of Hemorrhois hippocrepis and Malpolon monspessulanus highlights divergent karyotypes in Colubridae and Psammophiidae (Squamata: Serpentes)

    Get PDF
    Despite the growing interest in the evolutionary cytogenetics of squamates, chromosomal data are lacking for most taxa. We performed a preliminary molecular taxonomic analysis and a comparative cytogenetic study on Hemorrhois hippocrepis and Malpolon monspessulanus. We used a combination of standard karyotyping, chromomycin A3/Methyl green staining, C-banding, Ag-NOR staining and NOR-FISH to provide the first karyotype description of H. hippocrepis and a re-description of the karyotype of M. monspessulanus, including chromosome markers, heterochromatin patterns and sex chromosome systems. Our results show that H. hippocrepis has 2 n = 36 chromosomes, with 16 macro- and 20 microchromosomes and NORs on the 6th pair. The 4th pair represents homomorphic (metacentric) ZW sex chromosomes, but the W chromosome is completely heterochromatic. Malpolon monspessulanus has 2 n = 44 chromosomes, with 20 macro- and 24 microchromosomes, NORs on the 6th telocentric pair. The 4th pair represents the sex chromosomes (ZZ/ZW), with a W chromosome smaller than the Z and completely heterochromatic. Comparing our cytogenetic data to those available from the literature, we note the occurrence and distribution of primitive and derived chromosomal characteristics and discuss the chromosome diversification in two snake clades belonging to Colubridae and Psammophiidae, respectively. We highlight that these two families followed different chromosome diversification pathways, characterised by a highly conserved karyotype structure in Colubridae and a higher chromosome variability in Psammophiidae, mostly driven by a progressive reduction of the chromosome number by means of chromosome fusions. We also provide cytotaxonomic insights supporting the distinction between M. monspessulanus and M. insignitus

    A review of thermochemical energy storage systems for power grid support

    Get PDF
    Power systems in the future are expected to be characterized by an increasing penetration of renewable energy sources systems. To achieve the ambitious goals of the "clean energy transition", energy storage is a key factor, needed in power system design and operation as well as power-to-heat, allowing more flexibility linking the power networks and the heating/cooling demands. Thermochemical systems coupled to power-to-heat are receiving an increasing attention due to their better performance in comparison with sensible and latent heat storage technologies, in particular, in terms of storage time dynamics and energy density. In this work, a comprehensive review of the state of art of theoretical, experimental and numerical studies available in literature on thermochemical thermal energy storage systems and their use in power-to-heat applications is presented with a focus on applications with renewable energy sources. The paper shows that a series of advantages such as additional flexibility, load management, power quality, continuous power supply and a better use of variable renewable energy sources could be crucial elements to increase the commercial profitability of these storage systems. Moreover, specific challenges, i.e., life span and stability of storage material and high cost of power-to-heat/thermochemical systems must be taken in consideration to increase the technology readiness level of this emerging concept of energy systems integration

    Comparative cytogenetics on Zamenis lineatus and Elaphe quatuorlineata (Serpentes: Colubridae)

    Get PDF
    Because of their peculiar genomic and chromosomal characteristics, reptiles are extraordinary model organ-isms to study karyotype and sex chromosome evolution, but despite the growing interest in their evolutionary cytoge-netics, only a small fraction of species have a known karyotype. We performed a comparative cytogenetic analysis on Elaphe quatuorlineata and Zamenis lineatus, using classic and molecular techniques. We provide the karyotype of these two species and an assessment of their chromosomal features. Chromosome analysis was performed with standard kar-yotyping, C-banding, sequential C-banding + CMA3 + DAPI and Ag-NOR staining. On E. quatuorlineata, we also per-formed CMA3-methyl green staining and Fluorescence in situ Hybridization mapping NOR loci (NOR-FISH). Elaphe quatuorlineata and Z. lineatus show a very similar karyotype of 2n = 36, with 8 macro- and 10 microchromosome pairs, but differ in the morphology of the pair 8, which resulted submetacentric in the former and metacentric in the latter species. By comparing our data to those available from the literature on congeneric species, we analysed the occurrence of primitive and derivate chromosomal characters and provide cytotaxonomic insights, which further support the spe-cies status of Z. lineatus. In both species, the 4th pair was identified as the sex chromosome pair (ZZ/ZW) and NORs were localized on a microchromosome pair. We finally highlight in both genera Elaphe and Zamenis different stages of heterochromatinization of the W chromosome, in agreement with the progressive diversification model of sex chromo-some as already shown in different reptile taxa
    corecore