196,557 research outputs found
Toward a tomographic analysis of the cross-correlation between planck cmb lensing and h-atlas galaxies
No full textINAF PRIN; ASI/INAF [2014-024-R.0]; INFN-INDARK initiative; Spanish MINECOBianchini, F., Lapi, A., Calabrese, M., Bielewicz, P., Gonzalez-Nuevo, J., Baccigalupi, C., Danese, L., Zotti, G.D., Bourne, N., Cooray, A., Dunne, L., Eales, S., Valiante, E
Digital Mapping for the Neglected Built Heritage: the Case of Ferruzzano Superiore. Methodology and Outcomes
No full textA seguito di alcune premesse riguardanti le potenzialità e i possibili utilizzi
della cartografia digitale nei processi di conoscenza dei piccoli centri storici,
il presente contributo propone un metodo speditivo per valutare le principali
caratteristiche e lo stato di conservazione del patrimonio costruito di
piccoli insediamenti siti in aree marginali. Verranno illustrati nello specifico
l'approccio selezionato per la raccolta dei dati, la metodologia utilizzata per
elaborarli e i risultati ottenuti. Questa parte della ricerca RIBA ha l’obiettivo
di definire possibili modalità per comprendere le problematiche peculiari
dei piccoli centri storici a rischio di abbandono, sperimentando questo
approccio attraverso un caso studio, l'antico insediamento di Ferruzzano
Superiore (Reggio Calabria), per testimoniarne la flessibilità e la possibilità di
applicazione ad altri contesti simili. I dati raccolti attraverso rilievi speditivi
sul campo, che hanno riguardato le caratteristiche urbane e architettoniche
del patrimonio costruito e lo stato di conservazione delle strutture e dei
materiali, sono stati raccolti in un database digitale e sintetizzati in mappe
tematiche, evidenziando le criticità individuate. L’applicazione di questa
metodologia mostra come tale approccio, seppur speditivo, possa fornire
una base conoscitiva essenziale per supportare i processi decisionali che
coinvolgono il riutilizzo e la valorizzazione del patrimonio architettonico dei
piccoli centri storici
Documentary Appendix and Digital Data Inventory Methodologies: the GIS as Supporting Tool for Knowledge Processes of Historical Settlements
No full textIl contributo presenta la modalità con cui sono stati raccolti, inventariati e
messi in relazione i dati raccolti nel corso della ricerca. Uno degli obiettivi,
infatti, è stato di raccogliere e far dialogare la quantità di dati di natura
molto diversa collezionati durante le diverse fasi della ricerca. Il sistema Gis
qui utilizzato ha incluso la raccolta di dati a diverse scale (architettonica,
territoriale, sovralocale) e provenienti da diverse fonti (archivistiche,
cartografiche, documentarie, demografiche), che sono stati interconnessi
e georeferenziati con l'obiettivo di organizzare e presentare le informazioni
riguardanti ogni comune o sito. In particolare, la piattaforma GIS sviluppata
nel contesto della ricerca Lost and Found (RIBA 2021) mette in relazione la
dimensione territoriale, con approfondimenti su scala comunale di alcuni casi
studio identificati e li combina con una scala architettonica che si focalizza
sul caso di Ferruzzano (Reggio Calabria), con approfondimenti sullo stato di
conservazione del patrimonio edilizio. Questa piattaforma consente da un
lato di elaborare dati georeferenziati a supporto delle riflessioni proposte e
dall'altro di costruire uno strumento accessibile e fruibile, rivolto non solo ad
altri ricercatori ma anche ad attori locali
Quasar feedback in the early Universe: The case of SDSS J1148+5251
No full textGalaxy-scale gas outflows triggered by active galactic nuclei have been proposed as a key physical process to regulate the co-evolution of nuclear black holes and their host galaxies. The recent detection of a massive gas outflow in one of the most distant quasars, SDSS J1148+5251 at z = 6.4, presented by Maiolino et al., strongly supports this idea and suggests that strong quasar feedback is already at work at very early times. In a previous work, Valiante et al., we have presented a hierarchical semi-analytical model, GAMETE/QSOdust, for the formation and evolution of high-redshift quasars, and we have applied it to the quasar SDSS J1148+5251, with the aim of investigating the star formation history, the nature of the dominant stellar populations and the origin and properties of the large dust mass observed in the host galaxy. A robust prediction of the model is that the evolution of the nuclear black hole and of the host galaxy are tightly coupled by quasar feedback in the form of strong galaxy-scale winds. In the present Letter, we show that the gas outflow rate predicted by GAMETE/QSOdust is in good agreement with the lower limit of 3500 M circle dot yr(-1) inferred by the observations. According to the model, the observed outflow at z = 6.4 is dominated by quasar feedback, as the outflow rate has already considerably depleted the gas content of the host galaxy, leading to a downturn in the star formation rate at z <78. Hence, we predict that supernova explosions give a negligible contribution to the observed winds at z = 6.4
High-redshift quasars host galaxies: is there a stellar mass crisis?
No full textWe investigate the evolutionary properties of a sample of quasars (QSOs) at 5 <z <6.4 using the semi-analytical hierarchical model GAMETE/QSODUST. We find that the observed properties of these QSOs are well reproduced by a common formation scenario in which stars form according to a standard initial mass function, via quiescent star formation and efficient merger-driven bursts, while the central black hole (BH) grows via gas accretion and BH-BH mergers. Eventually, a strong active galactic nuclei-driven wind starts to clear up the interstellar medium of dust and gas, damping the star formation and un-obscuring the line of sight towards the QSO. In this scenario, all the QSOs hosts have final stellar masses in the range (4-6) × 1011 M⊙, a factor of 3-30 larger than the upper limits allowed by the observations. We discuss alternative scenarios to alleviate this apparent tension: the most likely explanation resides in the large uncertainties that still affect dynamical mass measurements in these high-z galaxies. In addition, during the transition between the starburst-dominated and the active QSO phase, we predict that ˜40 per cent of the progenitor galaxies can be classified as Submillimetre Galaxies, although their number rapidly decreases with redshift
Super-Eddington growth of the first black holes
No full textThe assembly of the first super massive black holes (SMBHs) at z ≳ 6 is still a subject of intense debate. If black holes (BHs) grow at their Eddington rate, they must start from ≳104 M⊙ seeds formed by the direct collapse of gas. Here, we explore the alternative scenario where ̃100 M⊙ BH remnants of the first stars grow at super-Eddington rate via radiatively inefficient slim accretion discs. We use an improved version of the cosmological, data-constrained semi-analytic model GAMETE/QSODUST, where we follow the evolution of nuclear BHs and gas cooling, disc and bulge formation of their host galaxies. Adopting SDSS J1148+5251 (J1148) at z = 6.4 as a prototype of luminous z ≳ 6 quasars, we find that ̃80 per cent of its SMBH mass is grown by super-Eddington accretion, which can be sustained down to z ̃ 10 in dense, gas-rich environments. The average BH mass at z ̃ 20 is MBH ≳ 104 M⊙, comparable to that of direct collapse BHs. At z = 6.4 the AGN-driven mass outflow rate is consistent with the observations and the BH-to-bulge mass ratio is compatible with the local scaling relation. However, the stellar mass in the central 2.5 kpc is closer to the value inferred from CO observations. Finally, ̃20 per cent of J1148 progenitors at z = 7.1 have BH luminosities and masses comparable to ULAS J1120+0641, suggesting that this quasar may be one of the progenitors of J1148
Bivariate landslide susceptibility analysis in the Lorestan Arc (Zagros Mountains, Iran)
No full textLandslide susceptibility analysis based on the assessment of a quantitative relationship between multiple controlling factors and landslide occurrence is a consolidated approach for land-use planning in risk mitigation. The Zagros Mountain range (Iran) is one of the most spectacular examples of a landscape whose evolution has been controlled by the erosion of rock outcrops and the growth of thrust-fold structures (predisposing factors for gravity-driven deformations). This paper covers a preliminary study on the landslide susceptibility of the Lorestan region of the Zagros Mountains. Use was made of a bivariate Frequency Ratio, computed on a 30 m pixel size Shuttle Radar Topography Mission Digital Elevation Model. In particular, reliance was made on an unpublished inventory of landslides in the Lorestan Arc. Landslide susceptibility was assessed in the “Falls” (323) and “Slides” (297) categories, the numbers of which (unlike those of other categories) were regarded as suitable for robust modelling. A multi-parametric analysis was carried out to determine the susceptibility of each type of landslide to a set of contributing factors. These factors, most of which are commonly used in the literature, can be grouped in two main categories: a) static, including morphological, hydraulic, and geological factors, and b) pseudo-dynamic, including distance from active faults and steepness index (ksn), a morphometric tectonic uplift proxy computed along stream networks. The latter were considered as potentially landslide-triggering factors in the medium-long term, combining both the effects of transient tectonic forces of individual seismic events and morphotectonic effects on the slope-valley system. The statistical significance of these pseudo-dynamic factors was initially demonstrated via a univariate logistic regression with a randomly generated set of “stable” and “unstable” points. Then, models were built, and the importance of each conditioning factor was assessed by calculating the contribution of the factors in determining the mean landslide susceptibility index value in actual landslides, and the percentage
of landslide cases in which the frequency ratio relative to each variable was above 1. With regard to the “Falls” category, the model showed (with a high reliability) that susceptible areas were those with a slope angle greater than 38°, associated with a 5000 m radius relief energy of about 1100-1550 m and a median fault distance of about 10 km. Conversely, the susceptibility model obtained for the “Slides” category showed that highly susceptible areas were those with slope angle values of 18°-35° and featuring outcrops of the most resistant lithotypes, such as limestone and marly limestone, especially close to flatiron landforms. The resulting model accuracy (validated with the prediction rate curve method on a sample dataset not used in the susceptibility analysis), was equal to 0.94 for “Falls” and 0.77 for “Slides”, indicating a good prediction accuracy
The role of heritage communities in local development processes through the reuse of architectural heritage. Some examples in Italian rural areas.
No full textOver the last three decades, various initiatives promoted by the European Union concerning the involvement and empowerment of communities in recognising and creating cultural values have flourished. They include, for instance, the Faro Convention, programs for ecomuseums and community mapping, and have contributed to giving voice to bottom-up initiatives for enhancing not only so-called monumental architecture but also "ordinary" architecture and built and vernacular cultural heritage. In general, this approach has also contributed to focusing attention on the importance of local communities in local development processes. In Italy, the so-called inner areas are often characterised by ordinary and vernacular heritage related to rural or manufacturing activities. In these small villages, some local communities, also thanks to the Italian National Strategy for Inner Areas, recognised the reuse of part of the vernacular local built heritage as a strength for the community itself and the broader context. Some cases have demonstrated that valorisation of architectural heritage is possible without creating tourism-related facilities only (hotels, museums, etc.) but also creating services needed by "local" users that facilitate the everyday life of the place. In this perspective, attention should also be focused on heritage education and the intergenerational transmission of knowledge, which should involve the entire community at different levels, starting from experiences already in place in similar contexts. In this sense, a community can be intended as a broad concept, a constantly evolving process that includes the resident citizens and a broader network related to a specific territory. Through analyses of case studies, this contribution aims to propose reflections on the role of heritage community experiences in empowering vernacular architectural heritage and its wider context
THE SYNTHESIS OF VITELLOGENIN WITHIN THE OVARIAN FOLLICLE IN TORPEDO MARMORATA.
No full textEurop J Histochem 47:3
A spatiotemporal object-oriented data model for landslides (LOOM)
No full textLOOM (landslide object-oriented model) is here presented as a data structure for landslide inventories based on the object-oriented paradigm. It aims at the effective storage, in a single dataset, of the complex spatial and temporal relations between landslides recorded and mapped in an area and at their manipulation. Spatial relations are handled through a hierarchical classification based on topological rules and two levels of aggregation are defined: (i) landslide complexes, grouping spatially connected landslides of the same type, and (ii) landslide systems, merging landslides of any type sharing a spatial connection. For the aggregation procedure, a minimal functional interaction between landslide objects has been defined as a spatial overlap between objects. Temporal characterization of landslides is achieved by assigning to each object an exact date or a time range for its occurrence, integrating both the time frame and the event-based approaches. The sum of spatial integrity and temporal characterization ensures the storage of vertical relations between landslides, so that the superimposition of events can be easily retrieved querying the temporal dataset. The here proposed methodology for landslides inventorying has been tested on selected case studies in the Cilento UNESCO Global Geopark (Italy). We demonstrate that the proposed LOOM model avoids data fragmentation or redundancy and topological inconsistency between the digital data and the real-world features. This application revealed to be powerful for the reconstruction of the gravity-induced deformation history of hillslopes, thus for the prediction of their evolution
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