Search results for "amer"

Metaphors in the descriptions of U.S. - Soviet/Russian summits in Newsweek and Novoje vremja

1999

Crystallographic analysis of extended defects in diamond-type crystals

2005

Abstract To investigate irradiation-induced Si amorphization during its initial stages, we have performed a classical molecular-dynamics (MD) calculation for the case of self-irradiation by 5 keV ions at a low temperature of 100 K. We examined the geometry of self-interstitial atom (SIA) clusters using the pixel mapping (PM) method, on the output data of MD calculations. Perfect crystalline silicon (c-Si) is amorphized by self-irradiation, and we observe that many SIA are produced. During sequential self-irradiation, the most frequently observed species were isolated SIA, i.e. I1 (monomer). The fractions of SIA clusters decreased as I2 (dimer), I3 (trimer), and I4 (tetramer) clusters, respe…

First tests of the applicability of gamma-ray imaging for background discrimination in time-of-flight neutron capture measurements

2015

In this work we explore for the first time the applicability of using $\gamma$-ray imaging in neutron capture measurements to identify and suppress spatially localized background. For this aim, a pinhole gamma camera is assembled, tested and characterized in terms of energy and spatial performance. It consists of a monolithic CeBr$_3$ scintillating crystal coupled to a position-sensitive photomultiplier and readout through an integrated circuit AMIC2GR. The pinhole collimator is a massive carven block of lead. A series of dedicated measurements with calibrated sources and with a neutron beam incident on a $^{197}$Au sample have been carried out at n_TOF, achieving an enhancement of a factor…

Intrinsic linearity of bakelite Resistive Plate Chambers operated in streamer mode

2019

Abstract Resistive Plate Chambers have largely been used in High Energy Physics and Cosmic Ray research. In view of using this detector for calorimetry applications it is important to know the maximum measurable particle density, or its intrinsic linearity limit, which is tightly related to the dimension of the discharge region. In this paper we report the results of measurements performed at the Beam Test Facility (INFN National Laboratory of Frascati, Italy) where the intrinsic linearity of bakelite RPCs operated in streamer mode has been tested at different impinging particle densities.

Fission fragment anisotropy for the 242mAm fission isomer by spin exchange pumping with polarized rubidium vapour

1992

Abstract The foundations of an experiment have been worked out with which, in principle, the spin, hyperfine constants and the isomer shift of the 14 ms fission isomer 242mAm can be measured. Such an experiment would be based on the fission fragment anisotropy signal which has actually been observed in this work after spin exchange pumping with polarized rubidium vapour in an optical buffer gas cell. A decrease of the count rate of (12±4)% has been measured at 90% with respect to the quantization axis. From this result it is concluded that the nuclear spin of the 242mAm fission isomer must be larger than 1. The low-energy fission isomers originating from the 242Pu(d, 2n)242mAm reaction have…

Acetylated nucleosome assembly on telomeric DNAs

2003

Abstract The role of histone N-terminal domains on the thermodynamic stability of nucleosomes assembled on several different telomeric DNAs as well as on ‘average’ sequence DNA and on strong nucleosome positioning sequences, has been studied by competitive reconstitution. We find that histone tails hyperacetylation favors nucleosome formation, in a similar extent for all the examined sequences. On the contrary, removal of histone terminal domains by selective trypsinization causes a decrease of nucleosome stability which is smaller for telomeres compared to the other sequences examined, suggesting that telomeric sequences have only minor interactions with histone tails. Micrococcal nuclease…

La construcción ideológica de la Restauración en Nueva España (1814-1816)

2020

La vuelta de Fernando VII en 1814 a la península y el golpe de Estado por el que procedió a anular la Constitución de Cádiz no supusieron, a ambos lados del Atlántico, un retorno a la situación previa a la crisis de 1808. Este trabajo examina dicho problema en el virreinato de la Nueva España desde el ámbito de los discursos para el periodo que transcurre entre 1814 y 1816. Para ello se relacionan tres perspectivas. En primer lugar, se confrontan algunos de los distintos proyectos que se plantearon dentro del absolutismo para efectuar la Restauración. Seguidamente, examinamos aquellos componentes teóricos que los intelectuales de la contrarrevolución utilizaron para legitimarla. Este proyec…

La imagen de la Mujer del Apocalipsis en Nueva España y sus implicaciones culturales

2013

Estudio de la imagen de la Inmaculada en el virreinato americano, y especialmente en su tipología alada, sobre la idea de la Mujer del Apocalipsis convertida en principal símbolo eclesiológico de triunfo de la causa concepcionista y de toda la institución eclesiástica virreinal. Para ello persigue distintos propósitos. En primer lugar, la ordenación del citado discurso siguiendo su plasmación por medio de la adopción y variación de los diversos tipos iconográfico como base que permite lanzar conclusiones culturales sustentadas. En segundo lugar, su implicación en la retórica visual novohispana por medio del análisis de la dimensión que alcanzaron los distintos alegatos, quien estuvo detrás …

Editor's Choice – European Society for Vascular Surgery (ESVS) 2021 Clinical Practice Guidelines on the Management of Venous Thrombosis

2021

European Society for Vascular Surgery (ESVS) 2021 Clinical Practice Guidelines on the Management of Venous Thrombosis

Gatekeeper of pluripotency: A common Oct4 transcriptional network operates in mouse eggs and embryonic stem cells

2011

Abstract Background Oct4 is a key factor of an expanded transcriptional network (Oct4-TN) that governs pluripotency and self-renewal in embryonic stem cells (ESCs) and in the inner cell mass from which ESCs are derived. A pending question is whether the establishment of the Oct4-TN initiates during oogenesis or after fertilisation. To this regard, recent evidence has shown that Oct4 controls a poorly known Oct4-TN central to the acquisition of the mouse egg developmental competence. The aim of this study was to investigate the identity and extension of this maternal Oct4-TN, as much as whether its presence is circumscribed to the egg or maintained beyond fertilisation. Results By comparing …