1,756 research outputs found

    Inclusiones de flores de Podopterus (Polygonaceae) del ámbar del Mioceno de Simojovel de Allende, Chiapas, México

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    Background and Aims: The Miocene amber from Chiapas, Mexico, shows high diversity of biological inclusions such as plants, fungi, arthropods, and vertebrates, being one of the most important amber-bearing areas worldwide. The aim of this work is to describe a new record based on four bisexual flowers belonging to the fossil species Podopterus mijangosae, that has been described recently based on its winged fruits only.Methods: The morphological and anatomical characteristics of the four fossil flowers were observed using a binocular stereoscopic microscope. The taxonomic affinity was decided by consulting specialized literature, as well as the review of herbarium material of the genera Podopterus, Fallopia, and Neomillspaughia of Polygonaceae.Key results: The four fossil specimens are bisexual, small, and have actinomorphic flowers, with differentiated perianth, three petals and three sepals per series, stamens are free and with thread-like filaments, anthers are dithecal and basifixed, the ovary is superior, syncarpous, 3-angular, with three free styles, and capitate stigmas. Conclusions: This new report of flowers of Podopterus adds more evidence that the family Polygonaceae was an important component of the tropical forest of Simojovel de Allende, Chiapas, Mexico, during the Miocene.Antecedentes y Objetivos: El ámbar del Mioceno de Chiapas, México, presenta una alta diversidad de inclusiones biológicas como plantas, hongos, artrópodos y vertebrados, siendo una de las áreas productoras de ámbar más importantes a nivel mundial. El objetivo de este trabajo es describir un nuevo registro basado en cuatro flores bisexuales pertenecientes a la especie fósil Podopterus mijangosae, que ha sido descrito recientemente con base solo en sus frutos alados. Métodos: Las características morfológicas y anatómicas de cuatro flores fósiles fueron observadas utilizando un microscopio estereoscópico. La afinidad taxonómica se realizó consultando literatura especializada, así como la revisión de material de herbario de los géneros Podopterus, Fallopia y Neomillspaughia de Polygonaceae.Resultados clave: Los cuatro especímenes fósiles están representadas por flores bisexuales, pequeñas, actinomorfas, con perianto diferenciado, tres pétalos y tres sépalos por serie, estambres libres con filamentos filiformes, anteras ditecas, basifijas, ovario súpero, sincarpo, tri-angular, con tres estilos libres y estigmas capitados. Conclusiones: Este nuevo reporte de flores de Podopterus agrega más evidencia de que la familia Polygonaceae fue un componente importante del bosque tropical de Simojovel de Allende, Chiapas, México, durante el Mioceno

    Floras tropicales cretácicas del norte de México y su relación con floras del Centro-Sur de América del Norte

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    Estudios previos sugieren que las selvas tropicales y paratropicales dominadas por angiospermas tuvieron una distribución importante en América del Norte durante el Cenozoico temprano (Paleoceno-Eoceno). Investigaciones recientes indican que floras bajo condiciones megatermales podrían haber estado presentes en el norte de México y centro-sur de Estados Unidos de América desde el Cretácico Superior (ca. 73 Ma). En Coahuila, en los sedimentos de las formaciones Cerro del Pueblo y Olmos, se han documentado diversas floras que, por su contenido fosilífero y su ubicación paleogeográfica, sugieren la presencia de selvas tropicales y paratropicales. Aquí hacemos un breve recuento de la composición fl orística, características fi sonómicas de las plantas, así como de las interpretaciones paleoclimáticas o paleoambientales de las paleofl oras del norte de México y centro-sur de EU. También analizamos la similitud fl orística de estas formaciones basados en morfogéneros de la madera. Nuestros resultados muestran que la similitud fl orística entre formaciones tiene cierta congruencia geográfi ca. Sin embargo, existen elementos con amplia distribución y otras plantas endémicas en localidades particulares, lo cual sugiere cierta diferenciación en su composición. La válidez de este patrón es, sin embargo, preliminar debido a la ausencia de un entendimiento profundo de la composición fl orística de estas comunidades hasta el momento

    Vulnerabilidad territorial ante la expansión urbana

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    En México según el INEGI para el 2010 la población urbana fue del 77.8%, lo que significa que un porcentaje importante de la población vive en localidades mayores a los 2500 habitantes. Las cuales tienen sus propios ritmos de crecimiento, funciones, especialización, cambios de usos del suelo y problemáticas específicas. Las ciudades principales se han expandido, en las últimas décadas, con escasa acción planificadora y bajos resultados en el ordenamiento territorial. Ello ha configurado crecimientos físicos dispersos y fragmentados con importantes efectos ambientales. En México, la dispersión urbana genera ocupación del territorio en riesgos, situaciones de vulnerabilidad con inexistencia de acciones públicas, porque se encuentra en pendientes abruptas, lugares que se inundan, en áreas naturales protegidas, entre otras formas, genera tejido construido en áreas no óptimas para el desarrollo urbano, todo ello impacta negativamente al medio ambiente y la calidad de vida de la población. El crecimiento urbano continuará porque en las ciudades se genera la riqueza del país, en ellas se encuentran las oportunidades y soluciones. La urbanización es el modelo para conseguir el desarrollo de la sociedad. En dicho desarrollo se aspira el crecimiento sustentable y armonioso con el ambiente. Se espera cambios regulatorios para revertir los efectos negativos generados durante décadas con la expansión urbana consumidora de recursos naturales, energía y recursos financieros. En este marco problemático se integra el libro “Vulnerabilidad territorial ante la expansión urbana”, es producto de las actividades científicas –foro y congreso realizados en 2015- de la Red internacional de territorios, sustentabilidad y gobernanza en México y Polonia (RETESYG) de la Facultad de Geografía, Facultad de Planeación Urbana y Regional de la Universidad Autónoma del Estado de México (UAEM), así como de la Facultad de Geografía y Estudios Regionales de la Universidad de Varsovia (UV) y la Facultad de Geografía y Biología de la Universidad Pedagógica “Comisión de Educación Nacional” de Cracovia. El libro tiene una visión integral de la vulnerabilidad territorial ante la expansión urbana, considera los enfoques de la geografía, de la planeación y del ordenamiento territorial para abordar las problemáticas ambiental y social. Presenta una visión amplia y de síntesis sobre vulnerabilidad del territorio y de las ciudades, en él se integran los saberes de la Geografía y de la Planeación Territorial. Destaca la necesidad de controlar el crecimiento anárquico y desordenado, las desigualdades sociales, los riesgos, los problemas ambientales, la falta de bases de datos geoespaciales dinámicas, entre otros. Los resultados de las investigaciones apuntan hacia el desarrollo territorial sustentable. El libro se conforma de dos partes, la primera presenta aspectos teóricos conceptuales y metodológicos de la vulnerabilidad territorial, estructural, física, ambiental y socioeconómica, los riesgos geomorfológicos, la sustentabilidad y manejo de recursos naturales, áreas naturales protegidas, metodologías para la evaluación de los impactos de la expansión metropolitana y gobernanza territorial. La segunda parte, desarrolla estudios de caso, a distintas escalas: desde huertos familiares, subcuentas, ciudad, municipio, zonas metropolitanas, megalópolis, regiones y país. En cada capítulo del libro se presenta bibliografía extensa, diversificada y actualizada que aportan al lector sobre el estado del arte de la vulnerabilidad territorial

    Pharmacokinetic Comparability of a Biosimilar Trastuzumab Anticipated from Its Physicochemical and Biological Characterization

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    Comparability between a biosimilar and its reference product requires the evaluation of critical quality attributes that may impact on its pharmacological response. Herein we present a physicochemical characterization of a biosimilar trastuzumab focused on the attributes related to the pharmacokinetic response. Capillary isoelectrofocusing (cIEF) and cation exchange chromatography (CEX) were used to evaluate charge heterogeneity; glycosylation profiles were assessed through hydrophilic interaction liquid chromatography (HILIC); aggregates content was evaluated through size exclusion chromatography (SEC) while binding affinity to FcRn was evaluated using isothermal titration calorimetry (ITC). The biosimilar trastuzumab and its reference product exhibited a high degree of similarity for the evaluated attributes. In regard to the pharmacokinetic parameters, randomized, double blind, and two-arm parallel and prospective study was employed after the administration of a single intravenous dose in healthy volunteers. No significant differences were found between the pharmacokinetic profiles of both products. Our results confirm that similarity of the critical quality attributes between a biosimilar product, obtained from a different manufacturing process, and the reference product resulted in comparable pharmacokinetic profiles, diminishing the uncertainty related to the biosimilar's safety and efficacy

    Estado del arte del proyecto

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    Es un proyecto de investigación en el aula, desarrollado por docentes del programa de arquitectura de la Universidad de la Costa con sede en Barranquilla, Colombia. En este se pueden constatar metodologías de enseñanza- aprendizaje diseñadas para cada caso y que representan la impronta personal de cada autor. Es importante resaltar, que todos los argumentos presentados en esta obra corresponden a experiencias diseñadas para asignaturas de las áreas de Diseño, representación y comunicación de proyectos, historia y teoría y Urbanismo. Una experiencia en la que docentes y estudiantes, configuran una vivencia, en el marco de una asignatura que sirve de referencia y aprendizaje en el ejercicio académic

    Search for vector-boson resonances decaying to a top quark and bottom quark in the lepton plus jets final state in pp collisions at s=13 TeV with the ATLAS detector

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    A search for new charged massive gauge bosons, W, is performed with the ATLAS detector at the LHC. Data were collected in proton–proton collisions at a center-of-mass energy of s=13 TeV and correspond to an integrated luminosity of 36.1 fb. This analysis searches for W bosons in the W→tb¯ decay channel in final states with an electron or muon plus jets. The search covers resonance masses between 0.5 and 5.0 TeV and considers right-handed W bosons. No significant deviation from the Standard Model (SM) expectation is observed and upper limits are set on the W→tb¯ cross section times branching ratio and the W boson effective couplings as a function of the W boson mass. For right-handed W bosons with coupling to the SM particles equal to the SM weak coupling constant, masses below 3.15 TeV are excluded at the 95% confidence level. This search is also combined with a previously published ATLAS result for W→tb¯ in the fully hadronic final state. Using the combined searches, right-handed W bosons with masses below 3.25 TeV are excluded at the 95% confidence level.Peer Reviewe

    Measurement of W±Z production cross sections and gauge boson polarisation in pp collisions at √s=13TeV with the ATLAS detector

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    This paper presents measurements of WZ production cross sections in pp collisions at a centre-of-mass energy of 13 TeV. The data were collected in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider, and correspond to an integrated luminosity of 36.1fb-1. The WZ candidate events are reconstructed using leptonic decay modes of the gauge bosons into electrons and muons. The measured inclusive cross section in the detector fiducial region for a single leptonic decay mode is σW±Z→ℓ′νℓℓfid.=63.7±1.0(stat.)±2.3(syst.)±1.4(lumi.) fb, reproduced by the next-to-next-to-leading-order Standard Model prediction of 61.5-1.3+1.4 fb. Cross sections for WZ and WZ production and their ratio are presented as well as differential cross sections for several kinematic observables. An analysis of angular distributions of leptons from decays of W and Z bosons is performed for the first time in pair-produced events in hadronic collisions, and integrated helicity fractions in the detector fiducial region are measured for the W and Z bosons separately. Of particular interest, the longitudinal helicity fraction of pair-produced vector bosons is also measured.We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS, CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TAEK, Turkey; STFC, UK; DOE and NSF, USA. In addition, individual groups and members have received support from BCKDF, CANARIE, CRC and Compute Canada, Canada; COST, ERC, ERDF, Horizon 2020, and Marie Skłodowska-Curie Actions, European Union; Investissements d’ Avenir Labex and Idex, ANR, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF, Greece; BSF-NSF and GIF, Israel; CERCA Programme Generalitat de Catalunya, Spain; The Royal Society and Leverhulme Trust, UK. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN, the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK) and BNL (USA), the Tier-2 facilities worldwide and large non-WLCG resource providers. Major contributors of computing resources are listed in Ref. [106].Peer Reviewe

    Search for heavy particles decaying into a top-quark pair in the fully hadronic final state in pp collisions at s =13 TeV with the ATLAS detector

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    A search for new particles decaying into a pair of top quarks is performed using proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at a center-of-mass energy of s=13 TeV corresponding to an integrated luminosity of 36.1 fb-1. Events consistent with top-quark pair production and the fully hadronic decay mode of the top quarks are selected by requiring multiple high transverse momentum jets including those containing b-hadrons. Two analysis techniques, exploiting dedicated top-quark pair reconstruction in different kinematic regimes, are used to optimize the search sensitivity to new hypothetical particles over a wide mass range. The invariant mass distribution of the two reconstructed top-quark candidates is examined for resonant production of new particles with various spins and decay widths. No significant deviation from the Standard Model prediction is observed and limits are set on the production cross-section times branching fraction for new hypothetical Z′ bosons, dark-matter mediators, Kaluza-Klein gravitons and Kaluza-Klein gluons. By comparing with the predicted production cross sections, the Z′ boson in the topcolor-assisted-technicolor model is excluded for masses up to 3.1-3.6 TeV, the dark-matter mediators in a simplified framework are excluded in the mass ranges from 0.8 to 0.9 TeV and from 2.0 to 2.2 TeV, and the Kaluza-Klein gluon is excluded for masses up to 3.4 TeV, depending on the decay widths of the particles.Peer Reviewe

    Search for pairs of highly collimated photon-jets in pp collisions at s =13 TeV with the ATLAS detector

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    Results of a search for the pair production of photon-jets - collimated groupings of photons - in the ATLAS detector at the Large Hadron Collider are reported. Highly collimated photon-jets can arise from the decay of new, highly boosted particles that can decay to multiple photons collimated enough to be identified in the electromagnetic calorimeter as a single, photonlike energy cluster. Data from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 36.7 fb-1, were collected in 2015 and 2016. Candidate photon-jet pair production events are selected from those containing two reconstructed photons using a set of identification criteria much less stringent than that typically used for the selection of photons, with additional criteria applied to provide improved sensitivity to photon-jets. Narrow excesses in the reconstructed diphoton mass spectra are searched for. The observed mass spectra are consistent with the Standard Model background expectation. The results are interpreted in the context of a model containing a new, high-mass scalar particle with narrow width, X, that decays into pairs of photon-jets via new, light particles, a. Upper limits are placed on the cross section times the product of branching ratios σ×B(X→aa)×B(a→γγ)2 for 200 GeV<mX<2 TeV and for ranges of ma from a lower mass of 100 MeV up to between 2 and 10 GeV, depending upon mX. Upper limits are also placed on σ×B(X→aa)×B(a→3π0)2 for the same range of mX and for ranges of ma from a lower mass of 500 MeV up to between 2 and 10 GeV.Peer Reviewe

    Search for tt¯ resonances in fully hadronic final states in pp collisions at √s = 13 TeV with the ATLAS detector

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    This paper presents a search for new heavy particles decaying into a pair of top quarks using 139 fb of proton-proton collision data recorded at a centre-of-mass energy of s = 13 TeV with the ATLAS detector at the Large Hadron Collider. The search is performed using events consistent with pair production of high-transverse-momentum top quarks and their subsequent decays into the fully hadronic final states. The analysis is optimized for resonances decaying into a tt¯ pair with mass above 1.4 TeV, exploiting a dedicated multivariate technique with jet substructure to identify hadronically decaying top quarks using large-radius jets and evaluating the background expectation from data. No significant deviation from the background prediction is observed. Limits are set on the production cross-section times branching fraction for the new Z′ boson in a topcolor-assisted-technicolor model. The Z′ boson masses below 3.9 and 4.7 TeV are excluded at 95% confidence level for the decay widths of 1% and 3%, respectively. [Figure not available: see fulltext.
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