4,355 research outputs found
Extending displacement-based earthquake loss assessment (DBELA) for the computation of fragility curves
This paper presents a new procedure to derive fragility functions for populations of buildings that relies on the
displacement-based earthquake loss assessment (DBELA) methodology. In the method proposed herein,
thousands of synthetic buildings have been produced considering the probabilistic distribution describing the
variability in geometrical and material properties. Then, their nonlinear capacity has been estimated using the
DBELA method and their response against a large set of ground motion records has been estimated. Global limit
states are used to estimate the distribution of buildings in each damage state for different levels of ground
motion, and a regression algorithm is applied to derive fragility functions for each limit state. The proposed
methodology is demonstrated for the case of ductile and non-ductile Turkish reinforced concrete frames with
masonry infills
Gli effetti dellâintroduzione della nuova mappa di pericolositĂ sulla valutazione del rischio sismico in Italia.
Lâintroduzione di una versione aggiornata della mappa di pericolositĂ sismica, definita per diversi periodi di ritorno e per svariati valori di ordinate spettrali, porta inevitabilmente a dei cambiamenti sul livello di rischio sismico del costruito italiano. PoichĂ© la relazione tra domanda e capacitĂ non Ăš lineare per tutto il range di periodi
di vibrazione strutturale, Ăš necessario valutare il cambiamento del livello di rischio sismico calcolando esplicitamente la vulnerabilitĂ sismica di strutture esistenti con diversi periodi di vibrazione, per diversi stati limite e considerando sia la nuova che la precedente definizione di pericolositĂ . Nel presente lavoro Ăš stato
eseguito un primo studio degli effetti che lâintroduzione di mappe aggiornate della pericolositĂ sismica potrebbe avere sulla valutazione dei livelli di rischio sismico nel territorio italiano. Le caratteristiche generali del costruito sono state ricavate dai dati del 14° Censimento Generale della Popolazione e delle Abitazioni (ISTAT
2001), mentre una procedura probabilistica di valutazione sismica per edifici esistenti a scala urbana Ăš stata impiegata per stimare la capacitĂ . Sono stati considerati tutti i tre stati limite prescritti dallâOrdinanza
(danno lieve, danno severo, collasso) in corrispondenza dei rispettivi valori di domanda, cosĂŹ come il cambiamento delle forme spettrali in funzione della localizzazione e del periodo di ritorno. I risultati dimostrano che la nuova mappa di pericolositĂ sismica porta a dei livelli di rischio sismico piĂč realistici e meno allarmanti,
rendendo leggermente meno gravoso, anche se non privo di problematiche, il panorama attuale di rischio in Italia
Masonry components
Masonry is a non-homogeneous material, composed of units and mortar, which can be of different types, with distinct mechanical properties. The design of both masonry units and mortar is based on the role of the walls in the building. Load-bearing walls relate to structural elements that bear mainly vertical loads, but can serve also to resist to horizontal loads. When a structural masonry building is submitted to in-plane and out-of-plane loadings induced by an earthquake for example, the masonry walls are the structural elements that ensure the global stability of the building. This means that the walls should have adequate mechanical properties that enable them to resist to different combinations of compressive, shear and tensile stresses.The boundary conditions influence the resisting mechanisms of the structural walls under in-plane loading and in a buildings the connection at the intersection walls are of paramount importance for the out-of-plane resisting mechanism. However, it is well established that the masonry mechanical properties are also relevant for the global mechanical performance of the structural masonry walls. Masonry units for load-bearing walls are usually laid so that their perforations are vertically oriented, whereas for partition walls, brick units with horizontal perforation are mostly adopted
Bright galaxies at Hubble's redshift detection frontier: Preliminary results and design from the redshift z~9-10 BoRG pure-parallel HST survey
We present the first results and design from the redshift z~9-10 Brightest of
the Reionizing Galaxies {\it Hubble Space Telescope} survey BoRG[z9-10], aimed
at searching for intrinsically luminous unlensed galaxies during the first 700
Myr after the Big Bang. BoRG[z9-10] is the continuation of a multi-year
pure-parallel near-IR and optical imaging campaign with the Wide Field Camera
3. The ongoing survey uses five filters, optimized for detecting the most
distant objects and offering continuous wavelength coverage from
{\lambda}=0.35{\mu}m to {\lambda}=1.7{\mu}m. We analyze the initial ~130
arcmin of area over 28 independent lines of sight (~25% of the total
planned) to search for z>7 galaxies using a combination of Lyman break and
photometric redshift selections. From an effective comoving volume of (5-25)
Mpc for magnitudes brighter than in the
-band respectively, we find five galaxy candidates at z~8.3-10
detected at high confidence (S/N>8), including a source at z~8.4 with mAB=24.5
(S/N~22), which, if confirmed, would be the brightest galaxy identified at such
early times (z>8). In addition, BoRG[z9-10] data yield four galaxies with . These new Lyman break galaxies with m are
ideal targets for follow-up observations from ground and space based
observatories to help investigate the complex interplay between dark matter
growth, galaxy assembly, and reionization.Comment: Accepted for publication on ApJ. 21 pages, 11 figures, 4 table
Naturally presented HLA class I-restricted epitopes from the neurotrophic factor S100-? are targets of the autoimmune response in type 1 diabetes
Type 1 diabetes (T1D) results from the destruction of pancreatic beta-cells by the immune system, and CD8(+) T lymphocytes are critical actors in this autoimmune response. Pancreatic islets are surrounded by a mesh of nervous cells, the peri-insular Schwann cells, which are also targeted by autoreactive T lymphocytes and express specific antigens, such as the neurotrophic factor S100-beta. Previous work has shown increased proliferative responses to whole S100-beta in both human T1D patients and the nonobese diabetic (NOD) mouse model. We describe for the first time naturally processed and presented epitopes (NPPEs) presented by class I human leukocyte antigen-A*02:01 (A2.1) molecules derived from S100-beta. These NPPEs triggered IFN-gamma responses more frequently in both newly diagnosed and long-term T1D patients compared with healthy donors. Furthermore, the same NPPEs are recognized during the autoimmune response leading to diabetes in A2.1-transgenic NOD mice as early as 4 wk of age. Interestingly, when these NPPEs are used to prevent diabetes in this animal model, an acceleration of the disease is observed together with an exacerbation in insulitis and an increase in S100-beta-specific cytotoxicity in vaccinated animals. Whether these can be used in diabetes prevention needs to be carefully evaluated in animal models before use in future clinical assays.-Calvino-Sampedro, C., Gomez-Tourino, I., Cordero, O. J., Reche, P. A., Gomez-Perosanz, M., Sanchez-Trincado, J. L., Rodriguez, M. A., Sueiro, A. M., Vinuela, J. E., Calvino, R. V. Naturally presented HLA class I-restricted epitopes from the neurotrophic factor S100-beta are targets of the autoimmune response in type 1 diabetes
Seismic hazard data for the new, Italian building code based on European standard
Prior to 2003 the Italian building code, established in 1974, was mostly based on
working stress design. The zonation that guided its application was made up in 1981
using a semi-quantitative, mainly seismological approach; it was enforced in 1984 and
left about 2/3 of the territory without seismic provisions.
In 1998 a new zonation was proposed but never adopted.
The 2002 Mw5.7 earthquake in Molise (Southern Italy) caused the collapse of a school
and the death of 26 children. The school was built in an area where seismic provisions
were not applied, although the zonation proposed in 1998 assigned it to the second
zone.
The earthquake triggered a process that led in a few months to a new set of seismic
provision
Gas-phase metallicity of 27 galaxies at intermediate redshift
The purpose of this work is to make available new gas-phase oxygen abundance
measurements for a serendipitous sample of 27 galaxies with redshift
0.35<z<0.52. We measured the equivalent widths of the [O II]{\lambda}3727,
H{\beta}, and [O III]{\lambda}{\lambda}4959, 5007 emission lines observed in
the galaxy spectra obtained with the Visible Multi-Object Spectrograph mounted
at the Very Large Telescope. For each galaxy, we derived the
metallicity-sensitive emission lines ratio R23, ionization-sensitive emission
lines ratio O32, and gas-phase oxygen abundance 12+log(O/H). The values of
gas-phase oxygen abundance 12+log(O/H) we obtained for the sample galaxies are
consistent with previous findings for galaxies at intermediate redshift.Comment: 5 pages, 3 postscript figures and 3 tables. A&A in pres
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