2,539 research outputs found
The Different Response of Apparently Identical Structures: a Far-Field Lesson from the Mirandola 20th May 2012 Earthquake
Abstract Twin structures, that is structures very similar in terms of geometry, materials, mass distribution etc., founded on the same soil and set at very close distance, are rationally expected to have an identical response to earthquakes. When this does not occur, a role is usually played by factors like the interaction with the surrounding structures or by other anomalies hidden behind the apparent similarity. We present the case of two apparently twin towers that showed a very different response to the 2012 Mirandola (Italy) earthquake ground shaking: one remained perfectly intact while the other had a wide set of fractures on secondary walls. This resulted to be the effect of several contributing factors: the stiffness of the two structures, experimentally measured, provided unexpected differences. This reflected into different modal frequencies for the two towers, with the first and second modes of the damaged tower coincident or very close to the soil resonance. The final result was a coupled soil-structure resonance, implying a much higher displacement of one tower compared to the other, under the same input motion. In Italy, insurance against earthquake damage will probably become compulsory in the near future. This case suggests that the specific soil-structure and structure-structure interaction will have to be carefully evaluated since they can critically affect even apparently identical structures
Unrelated bone marrow transplantation in Thalassemia. The experience of the Italian Bone Marrow transplant Group (GITMO)
BACKGROUND AND OBJECTIVES: Allogeneic bone marrow transplantation (BMT) is a widely accepted therapeutic approach in homozygous beta-thalassemia. However, the majority of patients do not have a genotypically identical donor within the family. This prompted us to conduct a pilot study to investigate the feasibility of matched unrelated bone marrow transplantation in thalassemia. The major drawback was the high risk of immunologic and transplant-related complications, mainly graft-versus-host disease (GvHD) and graft failure. DESIGN AND METHODS: Our aim was to reduce this risk through careful selection of donor/recipient pairs. HLA haplotypes that show a high linkage disequilibrium among their class I, class II and class III alleles are considered extended or ancestral haplotypes. RESULTS: These haplotypes are conserved and can be shared by apparently unrelated individuals. Our study shows that matching for these haplotypes significantly improves the outcome of unrelated bone marrow transplantation in thalassemia. In fact, results were comparable to those obtained in transplants using HLA-identifical family donors. INTERPRETATION AND CONCLUSIONS: Better results were obtained in patients with lesser iron overload and when the donor shared an identity for the DPB1 alleles
Point-occurrence self-similarity in crackling-noise systems and in other complex systems
It has been recently found that a number of systems displaying crackling
noise also show a remarkable behavior regarding the temporal occurrence of
successive events versus their size: a scaling law for the probability
distributions of waiting times as a function of a minimum size is fulfilled,
signaling the existence on those systems of self-similarity in time-size. This
property is also present in some non-crackling systems. Here, the uncommon
character of the scaling law is illustrated with simple marked renewal
processes, built by definition with no correlations. Whereas processes with a
finite mean waiting time do not fulfill a scaling law in general and tend
towards a Poisson process in the limit of very high sizes, processes without a
finite mean tend to another class of distributions, characterized by double
power-law waiting-time densities. This is somehow reminiscent of the
generalized central limit theorem. A model with short-range correlations is not
able to escape from the attraction of those limit distributions. A discussion
on open problems in the modeling of these properties is provided.Comment: Submitted to J. Stat. Mech. for the proceedings of UPON 2008 (Lyon),
topic: crackling nois
High-Precision 4D Tracking with Large Pixels using Thin Resistive Silicon Detectors
The basic principle of operation of silicon sensors with resistive read-out
is built-in charge sharing. Resistive Silicon Detectors (RSD, also known as
AC-LGAD), exploiting the signals seen on the electrodes surrounding the impact
point, achieve excellent space and time resolutions even with very large
pixels. In this paper, a TCT system using a 1064 nm picosecond laser is used to
characterize sensors from the second RSD production at the Fondazione Bruno
Kessler. The paper first introduces the parametrization of the errors in the
determination of the position and time coordinates in RSD, then outlines the
reconstruction method, and finally presents the results. Three different pixel
sizes are used in the analysis: 200 x 340, 450 x 450, and 1300 x 1300
microns^2. At gain = 30, the 450 x 450 microns^2 pixel achieves a time jitter
of 20 ps and a spatial resolution of 15 microns concurrently, while the 1300 x
1300 microns^2 pixel achieves 30 ps and 30 micron, respectively. The
implementation of cross-shaped electrodes improves considerably the response
uniformity over the pixel surface.Comment: 28 pages, 23 figures submitted to NIM
La ricostruzione dello scuotimento del terremoto del Garda del 2004 (ML=5.2)
Il terremoto di magnitudo ML=5.2 che nel 2004 ha colpito il lato
occidentale del Lago di Garda (Nord Italia) viene modellato sia
nellâapprossimazione di sorgente puntiforme sia mediante simulazioni
da sorgente estesa, al fine di investigare lâanisotropia del campo
di risentimento osservata tra 5 e 15 km di distanza epicentrale. Il
confronto con le osservazioni viene effettuato in termini intensitĂ
macrosismica IMCS osservata, considerando i soli comuni localizzati
su roccia (o formazione «rigida») fino a 40 km dallâepicentro; un
ulteriore confronto fra simulazioni e osservazioni viene effettuato
utilizzando i dati registrati dalla stazione accelerometrica di Vallio
Terme (GVD), localizzata a 13.3 km dallâepicentro, appartenente alla
rete nazionale (RAN).
Le simulazioni piĂč semplici utilizzano una sorgente puntiforme
ed equazioni predittive empiriche in termini di intensitĂ . Le modellazioni
a faglia estesa riproducono il campo di scuotimento in termini
di valori di picco dello scuotimento, successivamente convertiti in
intensitĂ attraverso relazioni empiriche. Nonostante la moderata
magnitudo dellâevento, le simulazioni a faglia estesa, che richiedono
lâassunzione di ipotesi plausibili sia sulla geometria della sorgente
che sulle proprietĂ di attenuazione del mezzo di propagazione, sono
in grado di confermare lâanisotropia osservata della distribuzione di
intensitĂ a scala regionale (30Ă30 km2). Inoltre, poichĂ© la distribuzione
delle intensitĂ presenta anche eterogeneitĂ a scala locale (di
dimensione inferiore a 3 km), probabilmente dovute ad effetti geologici
e geomorfologici, oppure ad effetti di interazione terreno-struttura,
nella seconda parte del lavoro vengono presentati alcuni esempi
di misure di rumore sismico e di misure di frequenza propria
degli edifici
Data Descriptor: Field-recorded data on the diet of six species of European Hydromantes cave salamanders
The availability of data on the feeding habits of species of conservation value may be of great importance to develop analyses for both scientific and management purposes. Stomach flushing is a harmless technique that allowed us to collect extensive data on the feeding habits of six Hydromantes species. Here, we present two datasets originating from a three-year study performed in multiple seasons (spring and autumn) on 19 different populations of cave salamanders. The first dataset contains data of the stomach content of 1,250 salamanders, where 6,010 items were recognized; the second one reports the size of the intact prey items found in the stomachs. These datasets integrate considerably data already available on the diet of the European plethodontid salamanders, being also of potential use for large scale meta-analyses on amphibian diet
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