101 research outputs found
Método preliminar para la evaluación de la calidad de superficies ecuestres
Las superficies ecuestres de arena y césped propuestas para la competencia o entrenamiento deben cumplir requisitos funcionales para asegurar calidad de la performance, bienestar animal y seguridad del jinete1. La FEI2 definió las características de las superficies ecuestres. Firmeza, amortiguación, rebote, agarre, uniformidad y consistencia. En las superficies donde se realizan competencias a nivel nacional e internacional como también en las superficies de entrenamiento es necesario monitorear los aspectos críticos de la respuesta de la superficie3. El objetivo del ensayo diseñar un método de evaluación que permita crear un protocolo de aplicación en certificación de competencias deportivas. El experimento consistió en relevar diversas superficies existentes en establecimientos ecuestres de distinto objetivo. Se realizaron mediciones mediante cuadrículas de 5x5 o de 10x10, de acuerdo al tamaño de la superficie. En cada estación se realizaron mediciones de espesor de amortiguación, test de Impacto, con un dispositivo similar al Clegg Hammer. La tracción longitudinal, se midió utilizando un dispositivo según norma ASTM F2333-04, además se utilizó el dispositivo denominado Going Stick. Se realizaron ensayos de caracterización gravimétrica de la arena y los materiales adicionados. El Contenido Volumétrico de Humedad4 se monitoreó con TDR. Los datos obtenidos se analizaron mediante ANVA y test de Tuckey. Las conclusiones preliminares indican que el método permite establecer con un grado de confianza las diferencias en uniformidad en distintos sectores de una superficie. Estas diferencias permiten diagnosticar el estado de la superficie y de este modo proceder con la práctica adecuada para su restauración. Repetir el método luego de las prácticas de restauración permiten monitorear la evolución de los parámetros medidos y se esperaría que signifiquen una mejora en las propiedades funcionales. Este método podría ser utilizado como protocolo de certificación de superficies ecuestres en competencias deportivas
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Synthesis of accelerograms compatible with the Chinese GB 50011-2001 design spectrum via harmonic wavelets: artificial and historic records
A versatile approach is employed to generate artificial accelerograms which satisfy the compatibility criteria prescribed by the Chinese aseismic code provisions GB 50011-2001. In particular, a frequency dependent peak factor derived by means of appropriate Monte Carlo analyses is introduced to relate the GB 50011-2001 design spectrum to a parametrically defined evolutionary power spectrum (EPS). Special attention is given to the definition of the frequency content of the EPS in order to accommodate the mathematical form of the aforementioned design spectrum. Further, a one-to-one relationship is established between the parameter controlling the time-varying intensity of the EPS and the effective strong ground motion duration. Subsequently, an efficient auto-regressive moving-average (ARMA) filtering technique is utilized to generate ensembles of non-stationary artificial accelerograms whose average response spectrum is in a close agreement with the considered design spectrum. Furthermore, a harmonic wavelet based iterative scheme is adopted to modify these artificial signals so that a close matching of the signals’ response spectra with the GB 50011-2001 design spectrum is achieved on an individual basis. This is also done for field recorded accelerograms pertaining to the May, 2008 Wenchuan seismic event. In the process, zero-phase high-pass filtering is performed to accomplish proper baseline correction of the acquired spectrum compatible artificial and field accelerograms. Numerical results are given in a tabulated format to expedite their use in practice
Response of AGATA Segmented HPGe Detectors to Gamma Rays up to 15.1 MeV
The response of AGATA segmented HPGe detectors to gamma rays in the energy
range 2-15 MeV was measured. The 15.1 MeV gamma rays were produced using the
reaction d(11B,ng)12C at Ebeam = 19.1 MeV, while gamma-rays between 2 to 9 MeV
were produced using an Am-Be-Fe radioactive source. The energy resolution and
linearity were studied and the energy-to-pulse-height conversion resulted to be
linear within 0.05%. Experimental interaction multiplicity distributions are
discussed and compared with the results of Geant4 simulations. It is shown that
the application of gamma-ray tracking allows a suppression of background
radiation following neutron capture by Ge nuclei. Finally the Doppler
correction for the 15.1 MeV gamma line, performed using the position
information extracted with Pulse-shape Analysis, is discussed.Comment: 10 pages, 11 figure
g-factor measurements of isomeric states in 174W
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.ISBN: 978-88-7438-101-2; International audience; The experimental setup GAMIPE used for gyromagnetic factormeasurements at Laboratori Nazionali di Legnaro and a recent experimentalwork regarding K-isomers in 174W are described. Aim ofthe experiment is to study the detailed structure of the isomeric stateswave functions, by the measurement of the magnetic dipole moments.This piece of information can provide interesting hints for theoreticalmodels. Preliminary results concerning the population of the isomersof interest and half-lives are presented
Study of the γ decay of high-lying states in 208Pb via inelastic scattering of 17O ions
High-lying states in 208Pb nucleus were populated via inelastic scattering of a 17O beam at bombarding energy of 20 MeV/u. Their subsequent gamma decay was measured with the detector system AGATA Demonstrator based on HPGe detectors, coupled to an array of large volume LaBr3:Ce scintillators. Preliminary results in comparison with (γ,γ′) data, for states in the 5–8 MeV energy interval, seem to indicate that in that region the states belong to two different groups one with a isoscalar character and the other with a isovector nature. This is similar to what was observed in other stable nuclei with (α,α′γ) experiments. The multipolarity of the observed gamma transitions is determined with remarkable sensitivity thanks to angular distribution measurements. Data aiming at studying the neutron decay of the Giant Quadrupole Resonance in the 208Pb by the high resolution measurement of the following gamma decay are also presented in their preliminary form
Towards the lowest-energy limit for light ions identification with silicon pixel-type detectors
An in-beam test of two pixel-type silicon detectors of the TRACE detector project has been performed at Laboratori Nazionali di Legnaro (Italy). The aim was to investigate the lowest kinetic energy values at which isotopic identification of heavy-ion reactions products with mass A 3c 10 is possible, by using a single-layer silicon detector. Two separate read-out chains, analog and digital, were used, and the Pulse Shape Analysis technique was employed to obtain the particle identification matrices for the digitally processed data. The results confirmed the high capability of the Pulse Shape Analysis method which can be used for light ion identification, with performances similar to the analog approach. Separation in both charge and mass was obtained for Li and Be isotopes, however, the presence of a significant background from alpha particles severely limited the data analysis in the lower energy region. Due to this effect, the identification of the light products ( 7,6 Li isotopes) could be possible down to 3c 24.5 MeV only, while the 9,7 Be isotopes were separable down to 3c 29 MeV. This gives the value of < 4 MeV/nucleon as the lowest kinetic energy for light products identification by using the pixel-type detectors of the TRACE project, in the present experimental conditions
Collectivity at the prolate-oblate transition:the 2<sub>1</sub><sup>+</sup> lifetime of <sup>190</sup>W
The neutron-rich rare isotope 190W is discussed as a candidate for a prolate-oblate transitional nucleus with maximum γ-softness. The collectivity of this isotope is assessed for the first time by the measurement of the reduced E2 transition probability of its first 2+ state to the ground state. The experiment employed the FAst TIming Array (FATIMA), comprised of 36 LaBr3(Ce) scintillators, which was part of the DESPEC setup at GSI, Darmstadt. The 41+ and 21+ states of 190W were populated subsequently to the decay of its 127(12) μs isomeric Jπ = 10- state. The mean lifetime of the 21+ state was determined to be τ = 274(28) ps, which corresponds to a B(E2; 21+ → 01+) value of 95(10) W.u. The results motivated a revision of previous calculations within an energy-density functional-based interacting boson model-2 approach, yielding E2 transition properties and spectroscopic quadrupole moments for tungsten isotopes. From comparison to theory, the new data suggest that 190W is at the transition from prolate to oblate structure along the W isotopic chain, which had previously been discussed as a nuclear shape-phase transition
Reaction dynamics and nuclear structure studies via deep inelastic collisions with heavy-ions: spin and parity assignment in (49)Ca
The population and gamma decay of neutron rich nuclei around 48Ca has been measured at Legnaro National Laboratory with the PRISMA-CLARA setup, using deep-inelastic collisions (DIC) on 64Ni, at an energy approximately twice the Coulomb barrier. The reaction properties of the main products are investigated, focusing on total cross sections and angular distributions both integrated in energy and associated to the population of specific excited states. Gamma spectroscopy studies are also performed, giving evidence, for the first time in transfer reactions with heavy ions, of a large spin alignment ( 3c70%), perpendicular to the reaction plane. This makes possible the use of angular distributions and polarization measurements to firmly establish the spin and parity of excited states populated in nucleon transfer channels, as in the case of 49Ca, where candidates for particle-core coupling are investigated. Both reaction and gamma spectroscopy studies demonstrate the relevance of DIC with heavy ions for a detailed investigation of moderately neutron rich systems
Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology
notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations
High-spin structure in the transitional nucleus 131Xe:Competitive neutron and proton alignment in the vicinity of the N = 82 shell closure
International audienceThe transitional nucleus Xe131 is investigated after multinucleon transfer in the Xe136+Pb208 and Xe136+U238 reactions employing the high-resolution Advanced γ-Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and as an elusive reaction product in the fusion-evaporation reaction Sn124(B11,p3n)Xe131 employing the High-efficiency Observatory for γ-Ray Unique Spectroscopy (HORUS) γ-ray array coupled to a double-sided silicon strip detector at the University of Cologne, Germany. The level scheme of Xe131 is extended to 5 MeV. A pronounced backbending is observed at ℏω≈0.4MeV along the negative-parity one-quasiparticle νh11/2(α=−1/2) band. The results are compared to the high-spin systematics of the Z=54 isotopes and the N=77 isotones. Large-scale shell-model calculations employing the PQM130, SN100PN, GCN50:82, SN100-KTH, and a realistic effective interaction reproduce the experimental findings and provide guidance to elucidate the structure of the high-spin states. Further calculations in Xe129−132 provide insight into the changing nuclear structure along the Xe chain towards the N=82 shell closure. Proton occupancy in the π0h11/2 orbital is found to be decisive for the description of the observed backbending phenomenon
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