788 research outputs found
The seaplane base Ivo Monti at S. Nicola Varano (FG): a monument of military archeology, between history and protection
Built in the years between 1915 and 1918, and located on the west bank of the \u201cVarano\u201d Lake, a bay running along the village of \u201cCagnano Varano\u201d, the \u201cIvo Monti\u201d seaplane base was erected on a pre-existing medieval settlement which belonged to the Benedictine Monks from the town of \u201cSan Nicola Imbuti\u201d.
During WWI, this seaplane base was turned, from a simple water airport, into a strategic military base for floatplanes. As a matter of fact, the large lagoon could be used as landing spot for the planes sent off to patrol the dalmatic coast, one of the historical regions of Croatia, then controlled by the Austrians.
After WWI, after the seaplane became an outdated technology, the \u201cIvo Monti\u201d base was progressively dismantled and then totally abandoned at the beginning of the 1950s.
In 2014, considering the historical relevance of this site and the unmistakable architectural value of its elements, a research framework agreement was signed between the \u201cDICEA\u201d Department of Marche Polytechnic University and the city council of the town hosting the site, aimed at the development of shared scientific research projects revolving around the study, the valorisation, and the restoration of the military complex in question, which had been in a complete state of decay and neglect for too long.
The still ongoing research project mentioned presents two main missions: the first is the historical reconstruction, the geometric mapping, and the robustness analysis of the ruins, by studying and faithfully representing the state of deterioration of the building materials and of the facilities; the second is the identification and the testing of potential architectural solutions for the conversion and the reuse of the site and of its facilities
ClustOfVar: An R Package for the Clustering of Variables
Clustering of variables is as a way to arrange variables into homogeneous
clusters, i.e., groups of variables which are strongly related to each other
and thus bring the same information. These approaches can then be useful for
dimension reduction and variable selection. Several specific methods have been
developed for the clustering of numerical variables. However concerning
qualitative variables or mixtures of quantitative and qualitative variables,
far fewer methods have been proposed. The R package ClustOfVar was specifically
developed for this purpose. The homogeneity criterion of a cluster is defined
as the sum of correlation ratios (for qualitative variables) and squared
correlations (for quantitative variables) to a synthetic quantitative variable,
summarizing "as good as possible" the variables in the cluster. This synthetic
variable is the first principal component obtained with the PCAMIX method. Two
algorithms for the clustering of variables are proposed: iterative relocation
algorithm and ascendant hierarchical clustering. We also propose a bootstrap
approach in order to determine suitable numbers of clusters. We illustrate the
methodologies and the associated package on small datasets
The K20 survey. III. Photometric and spectroscopic properties of the sample
The K20 survey is an ESO VLT optical and near-infrared spectroscopic survey
aimed at obtaining spectral information and redshifts of a complete sample of
about 550 objects to K_s\leq20.0 over two independent fields with a total area
of 52 arcmin^2. In this paper we discuss the scientific motivation of such a
survey, we describe the photometric and spectroscopic properties of the sample,
and we release the -band photometric catalog. Extensive simulations showed
that the sample is photometrically highly complete to K_s=20. The observed
galaxy counts and the R-K_s color distribution are consistent with literature
results. We observed spectroscopically 94% of the sample, reaching a
spectroscopic redshift identification completeness of 92% to K_s\leq20.0 for
the observed targets, and of 87% for the whole sample (i.e. counting also the
unobserved targets). Deep spectroscopy was complemented with multi-band deep
imaging in order to derive tested and reliable photometric redshifts for the
galaxies lacking spectroscopic redshifts. The results show a very good
agreement between the spectroscopic and the photometric redshifts with
=0.01 and with a dispersion of \sigma_{\Delta z}=0.09. Using
both the spectroscopic and the photometric redshifts, we reached an overall
redshift completeness of about 98%. The size of the sample, the redshift
completeness, the availability of high quality photometric redshifts and
multicolor spectral energy distributions make the K20 survey database one of
the most complete samples available to date for constraining the currently
competing scenarios of galaxy formation and for a variety of other galaxy
evolution studies.Comment: 13 pages, 10 figures, to appear in Astronomy & Astrophysic
Research in Geant4 electromagnetic physics design, and its effects on computational performance and quality assurance
The Geant4 toolkit offers a rich variety of electromagnetic physics models;
so far the evaluation of this Geant4 domain has been mostly focused on its
physics functionality, while the features of its design and their impact on
simulation accuracy, computational performance and facilities for verification
and validation have not been the object of comparable attention yet, despite
the critical role they play in many experimental applications. A new project is
in progress to study the application of new design concepts and software
techniques in Geant4 electromagnetic physics, and to evaluate how they can
improve on the current simulation capabilities. The application of a
policy-based class design is investigated as a means to achieve the objective
of granular decomposition of processes; this design technique offers various
advantages in terms of flexibility of configuration and computational
performance. The current Geant4 physics models have been re-implemented
according to the new design as a pilot project. The main features of the new
design and first results of performance improvement and testing simplification
are presented; they are relevant to many Geant4 applications, where
computational speed and the containment of resources invested in simulation
production and quality assurance play a critical role.Comment: 4 pages, 4 figures and images, to appear in proceedings of the
Nuclear Science Symposium and Medical Imaging Conference 2009, Orland
Quantifying the unknown: issues in simulation validation and their experimental impact
The assessment of the reliability of Monte Carlo simulations is discussed,
with emphasis on uncertainty quantification and the related impact on
experimental results. Methods and techniques to account for epistemic
uncertainties, i.e. for intrinsic knowledge gaps in physics modeling, are
discussed with the support of applications to concrete experimental scenarios.
Ongoing projects regarding the investigation of epistemic uncertainties in the
Geant4 simulation toolkit are reported.Comment: To be published in the Proceedings of the 13th ICATPP Conference on
Astroparticle, Particle, Space Physics and Detectors for Physics
Applications, Villa Olmo, Como, 3-7 October 201
A wide area survey for high-redshift massive galaxies. I. Number counts and clustering of BzKs and EROs
We have combined deep BRIz' imaging over 2x940 arcmin^2 fields obtained with
the Suprime-Cam on the Subaru telescope with JKs imaging with the SOFI camera
at the New Technology Telescope to search for high-redshift massive galaxies.
K-band selected galaxies have been identified over an area of ~920 arcmin^2 to
K_Vega=19.2, of which 320 arcmin^2 are complete to K_Vega=20. The BzK selection
technique was used to obtain complete samples of ~500 candidate massive
star-forming galaxies (sBzKs) and ~160 candidate massive, passively-evolving
galaxies (pBzKs), both at 1.4 5 criterion we also
identified ~850 extremely red objects (EROs). The surface density of sBzKs and
pBzKs is found to 1.20+/-0.05 arcmin^{-2} and 0.38+/-0.03 arcmin^{-2},
respectively. Both sBzKs and pBzKs are strongly clustered, at a level at least
comparable to that of EROs, with pBzKs appearing more clustered than sBzKs. We
estimate the reddening, star formation rates (SFRs) and stellar masses (M_*) of
the sBzKs, confirming that to K_Vega~20 median values are M_*~10^{11}M_sun, SFR
190M_sun yr^{-1}, and E(B-V)~0.44. The most massive sBzKs are also the most
actively star-forming, an effect which can be seen as a manifestation of
downsizing at early epochs. The space density of massive pBzKs at z~1.4-2 is
20%+/-7% that of similarly massive early-type galaxies at z~0, and similar to
that of sBzKs of the same mass. We argue that star formation quenching in these
sBzKs will result in nearly doubling the space density of massive early-type
galaxies, thus matching their local density.Comment: 19 pages, 13 figures, accepted by ApJ. While checking the proofs we
became aware of a material mistake of non-trivial scientific relevance. In
the original it was reported that the comoving volume density of passive
BzK-selected galaxies with =1.7 and more massive than 10^{11}M_sun was
45%+/-15% of the local number density of similarly massive early-type
galaxies. This fraction actually turns out to be 20%+/-7%. Section 6.4, point
5 in section 7, and the abstract have been modified accordingl
GRB 050223: A dark GRB in a dusty starburst galaxy
Aims: We aim at detecting and determining the properties of the host galaxy
of the dark GRB 050223.
Methods: We use VLT optical/NIR images coupled to Swift X-ray positioning,
and optical spectra of the host galaxy to measure its properties.
Results: We find a single galaxy within the Swift error box of GRB 050223. It
is located at z = 0.584 and its luminosity is L ~ 0.4 L*. Emission lines in the
galaxy spectrum imply an intrinsic SFR > 7 Msun/yr, and a large extinction A_V
> 2 mag within it. We also detect absorption lines, which reveal an underlying
stellar population with an age between 40 Myr and 1.5 Gyr.
Conclusions: The identification of a host galaxy with atypical properties
using only the X-ray transient suggests that a bias may be present in the
former sample of host galaxies. Dust obscuration together with intrinsic
faintness are the most probable causes for the darkness of this burst.Comment: 4 pages, 2 figures, accepted for publication in Astronomy &
Astrophysic
A model for electrode effects based on adsorption theory
A model to describe the electrode effects based on the adsorption theory is proposed. We assume that the coverage (i.e by gas bubbles, electrodeposition of compounds, etc) of the electrodes is governed by a kinetics equation where the adsorption term is proportional to the bulk current density, and the desorption term to the actual coverage. The adsorption can take place only on the uncovered part of the electrode. We show that the coverage is responsible for a variation of the interface properties of the electrode. The time dependence of the electric response of the cell, submitted to an external voltage, is determined by solving the differential equation for the coverage. We show that two regimes are expected. One, in the limit of small time, controlled by the charging of the surface interface, and one related to the coverage. The theoretical predictions are in reasonable agreement with the experimental data concerning the time dependence of the current and the current-voltage characteristics of a home-made photo-electrolyzer constituted by a BiVO4 photoanode and a Pt cathode. Moreover, a normalized current-voltage curve was obtained, which fit also literature data based on (i) electrolysis on cylindrical stainless-steel electrodes in NaOH electrolyte and (ii) electrolytic plasma nitrocarburizing of AISI 1020 steel discs in an Urea-based aqueous solution, demonstrating the versatility and broad range of application of the here proposed model
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