5,229 research outputs found
Are There Thresholds of Current Account Adjustment in the G7?
We find evidence of threshold behavior in current account adjustment for the G7 countries, such that the dynamics of adjustment towards equilibrium depend upon whether the current-account/ net-output ratio breaches estimated, country specific current account surplus or deficit thresholds. Both the speeds of adjustment and the size of the thresholds are found to differ significantly across countries. In addition, we also find evidence of shifts in means and variances of exchange rate changes, stock returns, and interest differentials that coincide with the current account adjustment regimes identified by the model.
Ti-MCM-41 materials synthesised at room temperature as catalysts for cyclisation of (±)-citronellal”
In the present work we extend the applicability of those Ti-MCM-41 materials, as heterogeneous catalysts, to produce an important intermediate, isopulegol, from the cyclisation of citronellal. The use of this kind of materials appears to be a good option over homogeneous catalysts, because they offer the advantage of recovery and, consequently, contribute to environmentally friendly processes
Computer graphics and urban archaeology Bracara Augusta’s case study
Computer graphics is undoubtedly an important tool, widely used for representing and manipulating enormous
amounts of highly complex information.
Usually, the archaeological information is highly complex, so its representation using computer graphics technology
is a true and engaging challenge.
Virtual reconstructions representing archaeological sites, as for example the roman town Bracara Augusta,
should be considered a fundamental tool for research improvement carried out by experts. It is also extremely
important for the uprising consciousness of cultural heritage.FCT - Fundação para a Ciência e a Tecnologia; GPCG - Grupo Português de Computação Gráfic
A multi-disciplinary approach for research and presentation of Bracara Augusta’s archaeological heritage
The purpose of this paper is to present an archaeological information system and
multimedia application used to record, manage and diffuse the data provided by the
excavations conducted, since 1976, in Braga, Portugal, and related to the “Urban Rescue
Project of Bracara Augusta”.
The Geographical Information System built to manage and process the archaeological
information (SIABRA), created by a team from the Archaeology Unit of Minho
University, which was responsible for the Project, is presented. A natural result and advantage
of this System is to simplify and enhance spatial analysis and data articulation
related to the main buildings which have already been found, as well as the urban interpretation.
One further advantage is the three dimensional model reconstruction, where a
specialist (archaeologist, architect, urbanist) can analyse and visualise complex and diachronic
information concerning the Roman town, in order to simplify the global understanding
of buildings, their reconstruction phases and the general relationships between
them.
The development of virtual environments reproducing archaeological sites, such
as the Roman town of Bracara Augusta, can be considered as an important and powerful
tool for facilitating the research of specialists and improving heritage consciousness.Consiglio Nazionale delle Ricerch
Computação gráfica e arqueologia urbana : o caso de Bracara Augusta
A Computação Gráfica é, seguramente, uma ferramenta importante, e crescentemente utilizada, para representar
e manipular grandes quantidades de informação de elevada complexidade.
Por sua vez a arqueologia, de uma forma geral, produz um manancial de informação de grande complexidade,
pelo que a sua representação utilizando as tecnologias da Computação Gráfica constitui um elevado e aliciante
desafio.
As reconstruções virtuais que representam arqueosítios, como, por exemplo, a cidade romana de Bracara
Augusta, devem ser consideradas uma ferramenta importante e fundamental para o desenvolvimento da investigação
levada a cabo por peritos (arqueólogos, arquitectos e especialistas em urbanismo) e para o despertar das
consciências relativamente à importância da herança cultural.Computer Graphics is undoubtedly an important tool, widely used for representing and manipulating enormous
amounts of high complex information.
Usually, the archaeological information is highly complex, so its representation using computer graphics technology
is a true and engaging challenge.
Virtual reconstructions representing archaeological sites, as for example the roman town Bracara Augusta,
should be considered a fundamental tool for the research improvement carried out by experts and extremely
important for the uprising of cultural heritage consciousness.Fundação Ilídio Pinho; FCT - Fundação para a Ciência e a Tecnologia; Programa Operacional Ciência, Tecnologia, Inovação do Quadro Comunitário de Apoio II
IGR J17488-2338: a newly discovered giant radio galaxy
We present the discovery of a large scale radio structure associated with IGR
J17488--2338, a source recently discovered by \emph{INTEGRAL} and optically
identified as a broad line AGN at redshift 0.24. At low frequencies, the source
properties are those of an intermediate-power FR II radio galaxy with a linear
size of 1.4\,Mpc. This new active galaxy is therefore a member of a class of
objects called Giant Radio Galaxies (GRGs), a rare type of radio galaxies with
physical sizes larger than 0.7\,Mpc; they represent the largest and most
energetic single entities in the Universe and are useful laboratories for many
astrophysical studies. Their large scale structures could be due either to
special external conditions or to uncommon internal properties of the source
central engine The AGN at the centre of IGR J17488--2338 has a black hole of
1.310 solar masses, a bolometric luminosity of
710erg\,s and an Eddington ratio of 0.3, suggesting that
it is powerful enough to produce the large structure observed in radio. The
source is remarkable also for other properties, among which its X-ray
absorption, at odds with its type 1 classification, and the presence of a
strong iron line which is a feature not often observed in radio galaxies.Comment: 4 pages, 3 figures, accepted for publication on Astronomy and
Astrophysic
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