31 research outputs found
Historic cartography of L'Aquila city as a support to the study of earthquake damaged buildings
The city-center of L'Aquila suffered big damages from the main seismic event (6th April 2009, 3:32 a.m., local time; Ml=5.8, Mw= 6.2) of the seismic sequence that included hundreds of aftershocks (more than 30 of them 3.5<5.0) (INGV, 2009). Causes and modality of the collapse of some buildings are still under investigation. A 1:2000 map representing the center of L'Aquila city at the beginning of twentieth century was recently found and the comparison of this map with contemporary ones can help the study of the causes of the different response to seismic stress to different aged buildings. This study represents the first step to build a database of historic buildings in L'Aquila to test a potential correlation between the anti-earthquake regulations adopted over the years and the resulting damages. A comparison with post earthquakes damage map and the map of seismic zoning was performer to find all the possible combination of other parameters that together with building age can help to evaluate building vulnerability
Knowing the past for managing the present: A comparison between historical cartography and satellite images for the study of Rome's city centre
The idea of this paper, develops from the consideration that, since the second half of the XXth century, urban planning of Italian historical centers seems constrained by the fear of compromising the architectures of the past. Rome's city centre, today UNESCO site, gathers a built up heritage that witness its long and unique existence. The missing industrialization phase that, during the XIXth century, determined the urban transformation of the great European capital cities, has permitted to a large area characterized by highly stratified urban tissue to survive. The aim of this project is to exploit the geometric precision and descriptive detail, characterizing the "Nuova pianta di Roma", published in 1748 by Giovanni Battista Nolli, fot studying the urban transformations at housing block level. The rigorous georeferencing of the historical cartography, allows for the spatial comparison with actual cartographies and with very high resolution satellite images, and the consequent analysis of the urban structure and its formal and functional contents
Development of a software to plan UAVs stereoscopic flight: An application on post earthquake scenario in L'Aquila city
On April 6, 2009, an earthquake hit the historic center of L'Aquila city, hundreds of victims, thousands of collapses. During the post-emergency a continuous monitoring of all building is crucial in order to guarantee that each structure at least will not worsen its stability until the final reconstruction is completed. So detailed surveying of all building is performed using different geomatic techniques as total stations, land photogrammetry, and laser scanners. Even if all these techniques can perfectly respond to many crucial post hazard needs, there are still many monitoring that cannot be completely carried on with traditional techniques. For these reasons, in this work, the advantages of using multirotor UAVs will be illustrated; UAVs can be fully remote controlled and so the geometry of photogrammetric image acquisition can be imposed. For this task planning of flight is essential so a package was realized to obtain actual photogrammetric stereoscopic acquisitions. © 2013 Springer-Verlag Berlin Heidelberg
development of a software to optimize and plan the acquisitions from uav and a first application in a post seismic environment
AbstractAn Unmanned Aerial Vehicle (UAV) is an aircraft without a human pilot on board. UAVs allow close-range photogrammetric acquisitions potentially useful for building large-scale cartography and acquisitions of building geometry. This is particularly useful in emergency situations where major accessibility problems limit the possibility of using conventional surveys. Presently, however, flights of this class of UAV are planned based only on the pilot's experience and they often acquire three or more times the number of images needed. This is clearly a time-consuming and autonomy-reducing procedure, which is certainly detrimental when extensive surveys are needed. For this reason new software, to plan the UAV's survey will be illustrated
Automatic three-dimensional features extraction: The case study of L'Aquila for collapse identification after April 06, 2009 earthquake
This paper illustrates an innovative methodology for post-earthquake collapsed building recognition, based on satellite-image classification methodologies and height variation information. Together, the techniques create a robust classification that seems to yield good results in this application field. In the first part of this study, two different feature extraction methodologies were compared, based respectively on pixel-based and object-oriented approaches. Then the classification results of the most accurate classification methodology, obtained on an eight band WorldView-2 monoscopic image, were completed with height variation information before and after the event. The height difference is calculated, comparing a photogrammetric DSM, obtained using a photogrammetric rigorous orbital model on some EROS-B 0.7 metre across-track stereopairs with a 'roof model' before the earthquake
Multiple Stellar Populations outside the tidal radius of NGC1851 through Gaia DR3 XP Spectra
Ancient Galactic Globular Clusters (GCs) have long fascinated astronomers due
to their intriguing multiple stellar populations characterized by variations in
light-element abundances. Among these clusters, Type-II GCs stand out as they
exhibit stars with large differences in heavy-element chemical abundances.
These enigmatic clusters, comprising approximately 17\% of analyzed GCs with
MPs, have been hypothesized to be the remnants of accreted dwarf galaxies. We
focus on one of the most debated Type~II GCs, NGC1851, to investigate its MPs
across a wide spatial range of up to 50 arcmin from the cluster center. By
using Gaia DR3 low-resolution XP spectra, we generate synthetic photometry to
perform a comprehensive analysis of the spatial distribution and kinematics of
the canonical and anomalous populations within this GC. By using appropriate
CMDs from the synthetic photometry in the BVI bands and in the
band introduced in this work, we identify distinct stellar sequences associated
with different heavy-element chemical composition. Our results suggest that the
canonical and the anomalous populations reside both inside and outside the
tidal radius of NGC1851, up to a distance that exceeds by 3.5 times its tidal
radius. However, 80\% of stars outside the tidal radius are consistent
with belonging to the canonical population, emphasizing its dominance in the
cluster's outer regions. Remarkably, canonical stars exhibit a more circular
on-sky morphology, while the anomalous population displays an elliptical shape.
Furthermore, we delve into the kinematics of the multiple populations. Our
results reveal a flat/increasing velocity dispersion profile in the outer
regions and hints of a tangentially anisotropic motion in the outer regions,
indicating a preference for stars to escape on radial orbits.Comment: 13 pages, 10 figures, accepted for publication in A&
Multiple stellar populations along the red Horizontal Branch and Red Clump of Globular Clusters
We exploit multi-band Hubble Space Telescope photometry to investigate
multiple populations (MPs) along the red horizontal branches (HBs) and red
clumps of fourteen metal-rich Globular Clusters (GCs), including twelve Milky
Way GCs and the Magellanic Cloud GCs NGC 1978 and NGC 416. Based on appropriate
two-color diagrams we find that the fraction of 1G stars in Galactic GCs
correlates with cluster mass, confirming previous results based on red-giant
branch (RGB) stars. Magellanic-Cloud GCs show higher fractions of 1G stars than
Galactic GCs with similar masses, thus suggesting that the environment affects
the MP phenomenon. We compared and combined our population fractions based on
HB with previous estimates from MS and RGB, and we used ground-based UBVI
photometry (available for NGC 104, NGC 5927, NGC 6366, NGC 6838) to extend the
investigation over a wide field of view. All studied GCs are consistent with
flat distributions of 1G and 2G stars within ~1 arcmin from the cluster center
except NGC 416, where the 2G is more centrally concentrated. 2G stars of NGC
104 and NGC 5927 are more centrally-concentrated than the 1G, whereas the
distribution is flat for NGC 6366 and NGC 6838. We discover that most of the
analyzed GCs exhibit extended sequences of 1G stars along the red HB, not
consistent with a simple population. The comparison between appropriate
synthetic and observed CMDs reveals that these extended distributions are
consistent with either star-to-star variation in helium or with an internal
metallicity spread, recalling the inhomogeneity of 1G stars along the ChMs.Comment: 27 pages, 20 figures, 5 tables, accepted for pubblication in Ap
Photometric binaries, mass functions, and structural parameters of 78 Galactic open clusters
Binary stars play a crucial role in our understanding of the formation and
evolution of star clusters and their stellar populations. We use Gaia Data
Release 3 to homogeneously analyze 78 Galactic open clusters and the unresolved
binary systems they host, each composed of two main sequence (MS) stars. We
first investigated the structural parameters of these clusters, such as the
core radius and the central density, and determined the cluster mass function
(MF) and total mass by interpolating the density profile of each cluster. We
measured the fraction of binaries with a large mass ratio and the fraction of
blue straggler stars (BSSs), and finally investigated possible connections
between the populations of binary stars and BSSs with the main parameters of
the host cluster. {Remarkably, we find that the MFs of 78 analyzed open
clusters follow a similar trend and are well reproduced by two single power-law
functions, with a change in slope around masses of 1. The fraction
of binary stars ranges from 15\% to more than 60\% without
significant correlation with the mass and the age of the host cluster.
Moreover, we detect hints of a correlation between the total fraction of binary
stars and the central density of the host cluster. We compared the fraction of
binary stars with that of BSSs, finding that clusters with high and low central
density exhibit different trends. The fraction of binaries does not
significantly change with the mass of the primary star and the mass ratio. The
radial distribution of binary stars depends on cluster age. The binaries of
clusters younger than 800\,Myr typically show a flat radial distribution,
with some hints of a double peak. In contrast, the binaries of the remaining
clusters are more centrally concentrated than the single stars, which is
similar to what is observed in globular clusters.Comment: 27 pages, 27 figures, accepted for publication in Astronomy &
Astrophysic
Hubble Space Telescope survey of Magellanic Cloud star clusters: photometry and astrometry of 113 clusters and early results
In the past few years, we have undertaken an extensive investigation of star clusters and their stellar populations in the Large and Small Magellanic Clouds (LMC and SMC) based on archival images collected with the Hubble Space Telescope. We present photometry and astrometry of stars in 101 fields observed with the Wide Field Channel of the Advanced Camera for Surveys and the Ultraviolet and Visual Channel and the Near-Infrared Channel of Wide Field Camera 3. These fields comprise 113 star clusters. We provide differential-reddening maps for those clusters with significant reddening variations across the field of view. We illustrate various scientific outcomes that arise from the early inspection of the photometric catalogs. In particular, we provide new insights into the extended main-sequence turnoff (eMSTO) phenomenon: (i) We detected eMSTOs in two clusters, KMHK 361 and NGC 265, which had no previous evidence of multiple populations. This finding corroborates the conclusion that the eMSTO is a widespread phenomenon among clusters younger than ~2 Gyr. (ii) The homogeneous color-magnitude diagrams (CMDs) of 19 LMC clusters reveal that the distribution of stars along the eMSTO depends on cluster age. (iii) We discovered a new feature along the eMSTO of NGC 1783, which consists of a distinct group of stars on the red side of the eMSTO in CMDs composed of UV filters. Furthermore, we derived the proper motions of stars in the fields of view of clusters with multi-epoch images. Proper motions allowed us to separate the bulk of bright field stars from cluster members and investigate the internal kinematics of stellar populations in various LMC and SMC fields. As an example, we analyze the field around NGC 346 to disentangle the motions of its stellar populations, including NGC 364 and BS 90, young and pre-main-sequence stars in the star-forming region associated with NGC 346, and young and old field stellar populations of the SMC. Based on these results and the fields around five additional clusters, we find that young SMC stars exhibit elongated proper-motion distributions that point toward the LMC, thus providing new evidence for a kinematic connection between the LMC and SMC.We thank the anonymous referee for various suggestions that improved the quality of the manuscript. This work has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research innovation programme (Grant Agreement ERC-StG
2016, No. 716082 ’GALFOR’, PI: Milone, http://progetti.dfa.unipd. it/GALFOR) and from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No. 101034319 and from the European Union – NextGenerationEU, beneficiary: Ziliotto. A.P.M., M.T., and E.D. acknowledge support from MIUR through the FARE project R164RM93XW SEMPLICE (PI: Milone). A.P.M. and M.T. have been supported by MIUR under PRIN program 2017Z2HSMF (PI: Bedin). This research was supported in part by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) through project number CE170100013. This work is based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute (STScI). STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555.Peer ReviewedPostprint (published version
How future surgery will benefit from SARS-COV-2-related measures: a SPIGC survey conveying the perspective of Italian surgeons
COVID-19 negatively affected surgical activity, but the potential benefits resulting from adopted measures remain unclear. The aim of this study was to evaluate the change in surgical activity and potential benefit from COVID-19 measures in perspective of Italian surgeons on behalf of SPIGC. A nationwide online survey on surgical practice before, during, and after COVID-19 pandemic was conducted in March-April 2022 (NCT:05323851). Effects of COVID-19 hospital-related measures on surgical patients' management and personal professional development across surgical specialties were explored. Data on demographics, pre-operative/peri-operative/post-operative management, and professional development were collected. Outcomes were matched with the corresponding volume. Four hundred and seventy-three respondents were included in final analysis across 14 surgical specialties. Since SARS-CoV-2 pandemic, application of telematic consultations (4.1% vs. 21.6%; p < 0.0001) and diagnostic evaluations (16.4% vs. 42.2%; p < 0.0001) increased. Elective surgical activities significantly reduced and surgeons opted more frequently for conservative management with a possible indication for elective (26.3% vs. 35.7%; p < 0.0001) or urgent (20.4% vs. 38.5%; p < 0.0001) surgery. All new COVID-related measures are perceived to be maintained in the future. Surgeons' personal education online increased from 12.6% (pre-COVID) to 86.6% (post-COVID; p < 0.0001). Online educational activities are considered a beneficial effect from COVID pandemic (56.4%). COVID-19 had a great impact on surgical specialties, with significant reduction of operation volume. However, some forced changes turned out to be benefits. Isolation measures pushed the use of telemedicine and telemetric devices for outpatient practice and favored communication for educational purposes and surgeon-patient/family communication. From the Italian surgeons' perspective, COVID-related measures will continue to influence future surgical clinical practice