123 research outputs found

    The Gómez-Alba palaeontological collection of the MGB-MCNB

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    Es presenta el catàleg de la col·lecció paleontològica que havia pertangut al recentment traspassat Dr. Julio Gómez-Alba, antic conservador de Paleontologia del Museu de Geologia de Barcelona, actualment integrat en el Consorci del Museu de Ciències Naturals de Barcelona. La proposta de donació de la col·lecció a la ciutat de Barcelona al novembre de 2010 fou acceptada per l’Institut de Cultura de Barcelona (ICUB) en data 11 de febrer de 2011. Formada per 4.990 exemplars i 25 lots, no és la col·lecció d’un investigador en paleontologia sinó la d’un paleontòleg generalista. Molts exemplars d’aquesta col·lecció foren figurats en una guia de camp elaborada per Gómez-Alba (1988) sobre els fòssils d’Espanya i d’Europa. El catàleg és, a part d’algunes correccions menors, transcripció literal de la base de dades originalment associada a la col·lecció que –des de la seva acceptació– no ha estat actualitzada ni revisada.Se presenta el catálogo de la colección paleontológica que había pertenecido al recientemente fallecido Dr. Julio Gómez-Alba, antiguo conservador de Paleontología del Museo de Geología de Barcelona, actualmente integrado en el Consorcio del Museo de Ciencias Naturales de Barcelona. La propuesta de donación de la colección a la ciudad de Barcelona se realizó en noviembre de 2010 y fue aceptada por el Instituto de Cultura de Barcelona (ICUB) en fecha 11 de febrero de 2011. Formada por 4.990 ejemplares y 25 lotes, no es la colección de un investigador en paleontología sino la de un paleontólogo generalista. Muchos ejemplares de esta colección fueron figurados en una guía de campo elaborada por Gómez-Alba (1988) sobre los fósiles de España y de Europa. El catálogo es, aparte de algunas correcciones menores, la transcripción literal de la base de datos originalmente asociada a la colección que –desde su aceptación– no ha sido actualizada ni revisadaWe present the catalogue of the palaeontological collection belonging to the late Dr. Julio Gómez-Alba, former curator of Palaeontology at Barcelona’s Museum of Geology, now integrated in Barcelona’s Natural History Museum Consortium. He proposed the donation of his collection to the city of Barcelona in November 2010 and the Barcelona’s Institute of Culture (ICUB) accepted it on the 11th February 2011. Formed by 4.990 specimens and 25 batches, it is not the collection of a palaeontological researcher but that of a general palaeontologist. Many items in this collection were figured in a field guide authored by Gómez-Alba (1988) dealing with the fossils of Spain and Europe. The catalogue is, apart from some minor corrections, the literal transcription of the database originally associated to the collection that –since its acceptation– has neither been updated nor revised

    Selandian-Thanetian larger foraminifera from the lower Jafnayn Formation in the Sayq area (eastern Oman Mountains)

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    The larger foraminifera of the lower part of the Jafnayn Formation outcropping in the Wadi Sayq, in the Paleocene series of the eastern Oman Mountains, have been studied and described in detail. The analysis have allowed us to develop a detailed systematic description of each taxa, constraining their biostratigraphic distribution and defining the associated foraminifera assemblages. The taxonomic study has permitted us to identify each morphotype precisely and describe three new taxa, namely, Ercumentina sayqensis n. gen. n. sp. Lacazinella rogeri n. sp. and Globoreticulinidae new family. The first assemblage is characterized by the presence of Coskinon sp., Dictyoconus cf. turriculus Hottinger and Drobne, Anatoliella ozalpiensis Sirel, Ercumentina sayqensis n. gen. n. sp. Serra-Kiel and Vicedo , Lacazinella rogeri n. sp. Serra-Kiel and Vicedo, Mandanella cf. flabelliformis Rahaghi, Azzarolina daviesi (Henson), Lockhartia retiata Sander, Dictyokathina simplex Smout and Miscellanites globularis (Rahaghi). The second assemblage is constituted by the forms Pseudofallotella persica (Hottinger and Drobne), Dictyoconus cf. turriculus Hottinger and Drobne, Lacazinella rogeri n. sp. Serra-Kiel and Vicedo, Azzarolina daviesi (Henson), Keramosphera? cf. iranica Rahaghi, Lockhartia haimei (Davies), Lockhartia retiata Sander, Sakesaria trichilata Sander, Kathina delseota Smout, Elazigina harabekayisensis Sirel, Daviesina khatiyahi Smout, and Miscellanea juliettae Leppig. The first assemblage can be considered to belong to the Shallow Bentic Zone SBZ2 (early Selandian age), and the second assemblage to the SBZ3 (late Selandian-early Thanetian age).This paper shows, for the first time in the Middle East area, a correlation between the Selandian larger foraminifera and planktonic foraminifera biozones

    Paleocene Larger Foraminifera from the Pyrenean Basin with a recalibration of the Paleocene Shallow Benthic Zones

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    A taxonomic study of the Paleocene larger foraminifera from the Pyrenean basin has led to the description of sixty taxa including two new species: Alveolina korresensis and Valvulineria bacetai. In this work, we present a chronostratigraphic recalibration of the Paleocene Shallow Benthic Zones SBZ 1 to SBZ 4 based on correlation with calcareous nannofossil and planktic foraminifera biozones, all integrated within the stratigraphic framework of Paleocene platform to basin depositional sequences established for the whole Pyrenean domain. The samples were collected in autochtonous and parautochtonous deposits from ten key stratigraphic sections, representative of coastal to platform margin depositional settings. The results from two sections representing base of slope facies with intercalations of calcareous turbidites, which include penecontemporaneous platform-derived biota have been integrated in the study. The regional chronostratigraphic framework is derived from magneto-biochronological studies carried out in the Zumaia section, the global reference section for the Danian-Selandian and Selandian-Thanetian GSSPs. A new calibration of the Paleocene SBZs is proposed. The SBZ 1 is constrained to the first 1.09m.y. of the Paleocene; this first Paleogene biozone lacks distinct larger foraminiferal markers and thus is defined by an association of non-exclusive taxa composed of Valvulineria patalaensis, Stomatorbina? binkhorsti, Planorbulina? antiqua and Bangiana hanseni. The SBZ 2 now appears as the biozone encompassing most of the Danian stage (from ca. 64.9m.a. to 61.6m.a.), and is characterized by the association of Haymanella elongata, Haymanella paleocenica, Kayseriella decastroi, Rotospirella conica, Pyrenerotalia depressa, Elazigin dienii, Ornatononion moorkensii and Paralockhartia eos. The SBZ 2-SBZ 3 boundary coincides with the base of the Selandian stage (ca. 61.6m.a.). The SBZ 3 biozone is defined by the occurrence of Glomalveolina primaeva, Periloculina slovenica, Vania anatolica, Coskinon rajkae, Fallotella alavensis, Cribrobulimina carniolica, Miscellanea yvettae, Miscellanea juliettae, Miscellanites primitivus, Miscellanites minutus, Ranikothalia soldadensis, “Operculina” heberti and Discocyclina seunesi. The SBZ 3-SBZ 4 boundary is now ascribed to ca. 57.2m.a. The SBZ 4 biozone appears characterized by Glomalveolina levis, Alveolina korresensis, Hottingerina lukasi, Daviesina garumnensis, Assilina yvettae, Assilina azilensis and Nummulites catari. The SBZ 4-SBZ 5 boundary is placed at the Paleocene-Eocene boundary event (ca. 56.0m.a.)

    Paleocene Larger Foraminifera from the Pyrenean Basin with a recalibration of the Paleocene Shallow Benthic Zones

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    A taxonomic study of the larger foraminifera found in Paleocene rocks from the Pyrenean basin has led to the description of sixty taxa including two new species: Alveolina korresensis and Valvulineria bacetai. In this work, we present a chronostratigraphic recalibration of the Paleocene Shallow Benthic Zones (SBZ 1 to SBZ 4) based on correlation with calcareous nannofossil and planktic foraminifera biozones, all integrated within the stratigraphic framework of Paleocene platform to basin depositional sequences established for the whole Pyrenean domain. The samples were collected in autochtonous and parautochtonous deposits from ten key shallow platform stratigraphic sections, representative from coastal to platform margin depositional settings. The results from two base of slope sections with numerous intercalations of calcareous turbidites with penecontemporaneous platform-derived biota have been integrated in the study. The regional chronostratigraphic framework is derived from magneto-biochronological studies carried out in the Zumaia section, global reference section for the Danian-Selandian and Selandian-Thanertian GSSPs. The new calibration of the Paleocene SBZs is summarized as follows. The SBZ 1 is constrained to the first 1.09 m.y. of the Paleocene; this first Paleogene biozone lacks distinct larger foraminifera biomarkers and thus is defined by an association of non-exclusive taxa composed of Valvulineria patalaensis, Stomatorbina? binkhorsti, P.? antiqua and Bangiana hanseni. The SBZ 2 now appears as the biozone encompassing most of the Danian stage (from ca. 64.91 m.y. to 61.6 m.y.), and is characterized by the association of Haymanella elongata, Haymanella paleocenica, Kayseriella decastroi, Rotospirella conica, Pyrenerotalia depressa, Elazigina dienii and Paralockhartia eos. The SBZ 2-SBZ 3 boundary coincides with the base of the Selandian stage (ca. 61.6 m.y.). The SBZ 3 biozone is defined by Glomalveolina primaeva, Periloculina slovenica, Vania anatolica, Coskinon rajkae, Fallotella alavensis, Cribrobulimina carniolica, Miscellanea yvettae, Miscellanea juliettae, Miscellanites primitivus, Miscellanites minutus, Ranikothalia soldadensis, Nummulites heberti and Discocyclina seunesi. The SBZ 3-SBZ 4 boundary is now ascribed to ca. 57.2 m.y. The SBZ 4 biozone appears characterized by Glomalveolina levis, Alveolina korresensis, Hottingerina lukasi, Daviesina garumnensis, Assilina yvettae, Assilina azilensis and Nummulites catari. The SBZ 4-SBZ 5 boundary is placed at the Paleocene-Eocene boundary event (ca. 56.0 m.y.)

    On classical q-deformations of integrable sigma-models

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    JHEP is an open-access journal funded by SCOAP3 and licensed under CC BY 4.0A procedure is developed for constructing deformations of integrable σ-models which are themselves classically integrable. When applied to the principal chiral model on any compact Lie group F, one recovers the Yang-Baxter σ-model introduced a few years ago by C. Klimčík. In the case of the symmetric space σ-model on F/G we obtain a new one-parameter family of integrable σ-models. The actions of these models correspond to a deformation of the target space geometry and include a torsion term. An interesting feature of the construction is the q-deformation of the symmetry corresponding to left multiplication in the original models, which becomes replaced by a classical q-deformed Poisson-Hopf algebra. Another noteworthy aspect of the deformation in the coset σ-model case is that it interpolates between a compact and a non-compact symmetric space. This is exemplified in the case of the SU(2)/U(1) coset σ-model which interpolates all the way to the SU(1, 1)/U(1) coset σ-modelPeer reviewedFinal Published versio

    New insights about the Upper Jurassic – Lower Cretaceous sedimentary successions from Asturias (NW Iberian Peninsula)

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    Detailed mapping of the Jurassic to pre-Albian deposits of central and eastern Asturias (NW of the Iberian Peninsula) has enabled several Upper Jurassic and Lower Cretaceous outcrops, previously assigned to other ages, to be identified. Where possible, these outcrops have been correlated with the well-known sequences outcropping on the Asturian coast. A new Jurassic unit, the Miyares Formation, has been defined, which consists of a Lower conglomerate Unit, a Middle Unit composed mainly of oolitic limestones and an Upper Unit comprising bioclastic and marly limestones with a rich fauna of larger foraminifera. The Lower Unit is interpreted as having been deposited in a fan delta, the Middle Unit represents a shallow marine high-energy environment, and the Upper Unit was deposited on a restricted shallow marine platform. The shallow-water foraminiferal assemblage from the Upper Unit is attributed to the Tithonian and the oldest Cretaceous rocks are Barremian; there is therefore a stratigraphic gap recorded in the study area, which might correspond to the latest Jurassic to Early Cretaceous p. p. timespan.Una cartografía geológica detallada de los depósitos jurásicos y cretácicos pre-albienses ha permitido identificar varios afloramientos del Jurásico Superior y del Cretácico Inferior, asignados previamente a otras edades. Donde ha sido posible, estos afloramientos han sido correlacionados con las sucesiones bien conocidas que afloran en la costa asturiana. Se ha definido una nueva unidad, la Formación Miyares, formada por una Unidad Inferior conglomerática, una Unidad Media mayoritariamente de calizas oolíticas y una Unidad Superior de calizas bioclásticas y margosas con abundantes macroforaminíferos. La Unidad Inferior se interpreta como depósitos de fan delta, la Unidad Media representa un ambiente marino somero de alta energía, y la Unidad Superior fue depositada en una plataforma marina somera restringida. El conjunto de foraminíferos de agua somera de la Unidad Superior se atribuye al Titoniense y las rocas más antiguas del Cretácico son del Barremiense; existe por lo tanto, en el área de estudio, una laguna estratigráfica que abarca la parte terminal del Jurásico y una parte del Cretácico Inferior

    Exact computation of one-loop correction to energy of pulsating strings in AdS_5 x S^5

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    In the present paper, which is a sequel to arXiv:1001:4018, we compute the one-loop correction to the energy of pulsating string solutions in AdS_5 x S^5. We show that, as for rigid spinning string elliptic solutions, the fluctuation operators for pulsating solutions can be also put into the single-gap Lame' form. A novel aspect of pulsating solutions is that the one-loop correction to their energy is expressed in terms of the stability angles of the quadratic fluctuation operators. We explicitly study the "short string" limit of the corresponding one-loop energies, demonstrating a certain universality of the form of the energy of "small" semiclassical strings. Our results may help to shed light on the structure of strong-coupling expansion of anomalous dimensions of dual gauge theory operators.Comment: 49 pages; v2: appendix F and note about antiperiodic fermions added, typos corrected, references adde

    On q-deformed symmetries as Poisson-Lie symmetries and application to Yang-Baxter type models

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    This is an author-created, un-copyedited version of an article accepted for publication in Journal of Physics A: Mathematical and Theoretical. The publisher is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/1-.1088/1751-8113/49/41/415402. © 2016 IOP Publishing Ltd.Yang–Baxter type models are integrable deformations of integrable field theories, such as the principal chiral model on a Lie group G or σ-models on (semi-)symmetric spaces G/F. The deformation has the effect of breaking the global G-symmetry of the original model, replacing the associated set of conserved charges by ones whose Poisson brackets are those of the q-deformed Poisson–Hopf algebra Uq ( ) g . Working at the Hamiltonian level, we show how this q-deformed Poisson algebra originates from a Poisson–Lie G-symmetry. The theory of Poisson–Lie groups and their actions on Poisson manifolds, in particular the formalism of the non-abelian moment map, is reviewed. For a coboundary Poisson–Lie group G, this non-abelian moment map must obey the Semenov-TianShansky bracket on the dual group G*, up to terms involving central quantities. When the latter vanish, we develop a general procedure linking this Poisson bracket to the defining relations of the Poisson–Hopf algebra Uq ( ) g , including the q-Poisson–Serre relations. We consider reality conditions leading to q being either real or a phase. We determine the nonabelian moment map for Yang–Baxter type models. This enables to compute the corresponding action of G on the fields parametrising the phase space of these models.Peer reviewe

    Alleviating the non-ultralocality of coset sigma models through a generalized Faddeev-Reshetikhin procedure

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    The Faddeev-Reshetikhin procedure corresponds to a removal of the non-ultralocality of the classical SU(2) principal chiral model. It is realized by defining another field theory, which has the same Lax pair and equations of motion but a different Poisson structure and Hamiltonian. Following earlier work of M. Semenov-Tian-Shansky and A. Sevostyanov, we show how it is possible to alleviate in a similar way the non-ultralocality of symmetric space sigma models. The equivalence of the equations of motion holds only at the level of the Pohlmeyer reduction of these models, which corresponds to symmetric space sine-Gordon models. This work therefore shows indirectly that symmetric space sine-Gordon models, defined by a gauged Wess-Zumino-Witten action with an integrable potential, have a mild non-ultralocality. The first step needed to construct an integrable discretization of these models is performed by determining the discrete analogue of the Poisson algebra of their Lax matrices.Comment: 31 pages; v2: minor change

    Bethe Ansatz in Stringy Sigma Models

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    We compute the exact S-matrix and give the Bethe ansatz solution for three sigma-models which arise as subsectors of string theory in AdS(5)xS(5): Landau-Lifshitz model (non-relativistic sigma-model on S(2)), Alday-Arutyunov-Frolov model (fermionic sigma-model with su(1|1) symmetry), and Faddeev-Reshetikhin model (string sigma-model on S(3)xR).Comment: 37 pages, 11 figure
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