Control y administración de pesos y medidas en las ciudades del Imperio romano (“Pars occidentalis”)

In this paper, we examine how members of the Roman administration controlled and managed the weight and measure systems, both in the Urbs and in various towns and colonies in the Western Empire. We examine which magistrates were in charge of this task and the powers assigned to them. Similarly, we assess the expansion these measurement tools reached, how they were financed, as well as the methods used and the participation of various governmental authorities in their standardization and implementation at the local level. Finally, we study the spatial context in which these tools were located.En este trabajo, analizamos cómo los miembros de la administración romana controlaron y gestionaron el sistema de pesos y medidas, tanto en la Urbs, como en los distintos municipios y colonias de la parte occidental del Imperio. Examinamos qué magistrados estuvieron al cargo de esta labor y las competencias que les fueron asignadas. Igualmente, evaluamos el grado de difusión que alcanzaron los instrumentos de medición romanos, cómo fueron financiados, así como los métodos usados y la participación de las diferentes autoridades gubernativas en su estandarización e implantación en el ámbito local. Por último, estudiamos el contexto espacial en el que se emplazaron estos instrumentos

Nonlinear manifold learning for model reduction in finite elastodynamics

Model reduction in computational mechanics is generally addressed with linear dimensionality reduction methods such as Principal Components Analysis (PCA). Hypothesizing that in many applications of interest the essential dynamics evolve on a nonlinear manifold, we explore here reduced order modeling based on nonlinear dimen- sionality reduction methods. Such methods are gaining popularity in diverse fields of science and technology, such as machine perception or molecular simulation. We consider finite deformation elastodynamics as a model problem, and identify the manifold where the dynamics essentially take place –the slow manifold– by nonlinear dimensionality reduction methods applied to a database of snapshots. Contrary to linear dimensionality reduction, the smooth parametrization of the slow manifold needs special techniques, and we use local maximum entropy approximants. We then formulate the Lagrangian mechanics on these data-based generalized coordinates, and de- velop variational time-integrators. Our proof-of-concept example shows that a few nonlinear collective variables provide similar accuracy to tens of PCA modes, suggesting that the proposed method may be very attractive in control or optimization applications. Furthermore, the reduced number of variables brings insight into the me- chanics of the system under scrutiny. Our simulations also highlight the need of modeling the net e ¿ ect of the disregarded degrees of freedom on the reduced dynamics at long times

Disentangling jet and disc emission from the 2005 outburst of XTE J1118+480

The black hole X-ray transient, XTE J1118+480, has now twice been observed in outburst - 2000 and 2005 - and on both occasions remained in the low/hard X-ray spectral state. Here we present radio, infrared, optical, soft X-ray and hard X-ray observations of the more recent outburst. We find that the lightcurves have very different morphologies compared with the 2000 event and the optical decay is delayed relative to the X-ray/radio. We attribute this lesser degree of correlation to contributions of emission from multiple components, in particular the jet and accretion disc. Whereas the jet seemed to dominate the broadband spectrum in 2000, in 2005 the accretion disc seems to be more prominent and we use an analysis of the lightcurves and spectra to distinguish between the jet and disc emission. There also appears to be an optically thin component to the radio emission in the 2005 data, possibly associated with multiple ejection events and decaying as the outburst proceeds. These results add to the discussion that the term "low/hard state'" covers a wider range of properties than previously thought, if it is to account for XTE J1118+480 during these two outbursts.Comment: Accepted for publication in MNRA

Fractal-like aggregates: Relation between morphology and physical properties

A number of modern technological applications require a detailed calculation of the physical properties of aggregated aerosol particles. For example, in probing soot aerosols by the method called laser-induced incandescence (LII), the soot clusters are suddenly heated by a short, powerful laser pulse and then cool down to the temperature of the carrier gas. LII sizing is based on rigorous calculation of the soot aggregate heat-up and cooling and involves prediction of laser light absorption and energy and mass transfer between aggregated particles and the ambient gas. This paper describes results of numerical simulations of the mass or energy transfer between the gas and fractal-like aggregates of N spherical particles in either the free-molecular or continuum regime, as well as the light scattering properties of random fractal-like aggregates, based on Rayleigh–Debye–Gans (RDG) theory. The aggregate geometries are generated numerically using specially developed algorithms allowing “tuning” of the fractal dimension and prefactor values. Our results are presented in the form of easily applicable scaling laws, with special attention paid to relations between the aggregate gyration radius and the effective radius describing various transport processes between the aggregates and the carrier gas

Nuclear PDFs

We present the latest global QCD analysis of nuclear parton distribution functions. The emerging picture is one of consistency, with universal nuclear modification factors reproducing the main features of the data. Differences with previous analyses are addressed

In-flight calibration of the INTEGRAL/IBIS mask

Since the release of the INTEGRAL Offline Scientific Analysis (OSA) software version 9.0, the ghost busters module has been introduced in the INTEGRAL/IBIS imaging procedure, leading to an improvement of the sensitivity around bright sources up to a factor of 7. This module excludes in the deconvolution process the IBIS/ISGRI detector pixels corresponding to the projection of a bright source through mask elements affected by some defects. These defects are most likely associated with screws and glue fixing the IBIS mask to its support. Following these major improvements introduced in OSA 9, a second order correction is still required to further remove the residual noise, now at a level of 0.2-1% of the brightest source in the field of view. In order to improve our knowledge of the IBIS mask transparency, a calibration campaign has been carried out during 2010-2012. We present here the analysis of these data, together with archival observations of the Crab and Cyg X-1, that allowed us to build a composite image of the mask defects and to investigate the origin of the residual noise in the IBIS/ISGRI images. Thanks to this study, we were able to point out a simple modification of the ISGRI analysis software that allows to significantly improve the quality of the images in which bright sources are detected at the edge of the field of view. Moreover, a refinement of the area excluded by the ghost busters module is considered, and preliminary results show improvements to be further tested. Finally, this study indicates further directions to be investigated for improving the ISGRI sensitivity, such as taking into account the thickness of the screws in the mask model or studying the possible discrepancy between the modeled and actual mask element bridges.Comment: accepted for publication in the proceedings of "An INTEGRAL view of the high-energy sky (the first 10 years)" 9th INTEGRAL Workshop, October 15-19, 2012, Paris, France, in Proceedings of Science (INTEGRAL 2012), Eds. A. Goldwurm, F. Lebrun and C. Winkler, (http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=176), id 154; 6 pages, 4 figures, see the PoS website for the full resolution versio

Reflexiones en torno al cuatorvirato en la Hispania romana

A pesar del notable aumento de los estudios sobre vida y administración municipal romana, son aún muchos los aspectos que desconocemos sobre el tema. Uno de ellos es el cuatorvirato. Este artículo ofrece un corpus revisado y actualizado sobre aquellas fuentes que mencionan el cuatorvitaro en la Península Ibérica. Nuestro objetivo es comprobar la supuesta existencia de un doble colegio en el seno de esta magistratura, así como su relación con el estatuto de las comunidades en las que se implantó...In spite of the notable increase in the studies on life and Roman municipal administration, there are certain aspects which are still unknown for the scholars. One of them is the quattuorvir. This article offers an updated corpus on those sources that mention the quattuorvir in Iberian Peninsula. Our objective is to prove the supposed existence of a doble association in the bosom of the magistracy as well as, its conection to the statute of the communities in those which ís institute..