145 research outputs found
PONTI AD ARCHI GEMELLI IN PROVINCIA DI TERAMO: PROVE DINAMICHE E IDENTIFICAZIONE
No full textQuesto lavoro riguarda l’utilizzo di prove dinamiche in operational conditions per l’identificazione e la successiva validazione di modelli a elementi finiti.
Le prove dinamiche hanno avuto il duplice scopo di costituire il termine di riferimento in relazione a prove future previste nell’ambito di un programma di monitoraggio strutturale e di consentire, contestualmente, l’identificazione dei parametri e la validazione di modelli a elementi finiti. Fenomeni di veering
delle frequenze di due modi successivi sono stati evidenziati in due casi e gli aspetti teorici sono stati analizzati nel contesto della teoria classica delle oscillazioni lineari
Differential equations for real-structured defectivity measures.
No full textLet be a real matrix with all distinct eigenvalues. We propose a new method for the computation of the distance of the matrix from the set of real defective matrices, i.e., the set of those real matrices with at least one multiple eigenvalue with algebraic multiplicity larger than its geometric multiplicity.
For 0 < \eps \le w_\R(A), this problem is closely related to the computation of the most ill-conditioned \eps-pseudoeigenvalues of , that is points in the \eps-pseudospectrum of characterized by the highest condition number.
The method we propose couples a system of differential equations on a low rank manifold which determines the \eps-pseudoeigenvalue closest to coalesce, with a fast Newton-like iteration aiming to determine the minimal value \eps such that an \eps-pseudoeigenvalue becomes defective.
The method has a local behaviour; this means that in general we find upper bounds for . However, they usually provide good approximations, in those (simple) cases where we can check this.
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The methodology can be extended to a structured matrix, where it is required that the distance is computed within some manifold defining the structure of the matrix. In this paper we extensively examine the case of real matrices. As far as we know, there do not exist methods in the literature able to compute such distance
Le concentrazioni degli acidi organici quali indicatori per la valutazione qualitativa degli insilati di mais
No full textThirty nine corn silage samples, produced in 2007 in Teramo Province (Italy) were analysed for chemical composition, fibre fractions, soluble protein (Cornell), pH and organic acids content (citric, D-(+)-malic, trans-aconitic, D,L-lactic, acetic, fumaric, propionic, and n- butyric. None sample showed detectable amount of citric, fumaric and n-butyric acids while only 26% of samples showed detectable amount of propionic, 62% of D-(+)-malic acid and 82% of trans-aconitic. pH do not seems to be an helpful parameter to evaluate fermentation characteristics of corn silage indeed the greater correlation regarding pH were thats with NDF (r=0.576; P<0,001) and soluble protein (r=0.565; P<0,001) due probably to their buffer capacity. Dry matter (DM) of corn silage was strongly and negatively related to crude protein (-0,718; P<0,001), total organic acids content (TOAC; r=-0,826; P<0,001) and NDF (r=-0,61; P<0,001). Furthermore acetic acid was more related to TOAC than lactic acid (r=-0,827 vs r=-0,656; P<0,001) indeed total organic acids content was negatively related to lactic/acetic ratio (r=-0,619; P<0,01). Data of this paper suggest that wet corn silages is often better preserved than others because more rich in organic acids
Ultrasound enhanced with sulphur-hexafluoride-filled microbubbles agent (SonoVue) in the follow-up of mild liver and spleen trauma
No full textThis study assessed the role of contrast-enhanced ultrasound (CEUS) in the follow-up of patients with a diagnosis of traumatic liver or spleen lesions. Between April 2006 and February 2008, 18 patients (13 males and five females, age range 8-42 years) with blunt abdominal trauma were evaluated with computed tomography (CT) and CEUS at the emergency department of our institution. Seven were diagnosed as surgical emergencies and were excluded from the study. The remaining 11 were treated conservatively and were monitored with CEUS at variable time intervals, depending on their clinical needs. CEUS confirmed lesion sites identified on presentation and allowed us to follow all phases of the repair process until complete resolution. The conservative management of abdominal lesions in both adults and children is increasingly widespread but requires accurate follow-up over time. As a noninvasive, versatile, easy to perform and repeatable technique with a low rate of adverse reactions, CEUS is ideally suited for this purpose and allowed us to reduce the number of CT scans, especially in the follow-up of young patients
Effects of loading methods on rabbit welfare and meat quality
No full textThe effects of different loading methods on the welfare, carcass characteristics and meat quality traits of hybrid commercial rabbits were investigated. 384 male rabbits, 82 days old, were transported from the farm to the slaughterhouse. At the farm, 192 rabbits were loaded onto the truck smoothly (S) and 192 rabbits were loaded roughly (R). The S loading method consisted of carefully placing each rabbit into the transport crates. In the R method, the loading was hurriedly and carelessly executed by the transport operator, throwing each animal into the crates fixed on the truck.
Live weight before and after transport as well as slaughter data were recorded for each rabbit, and a subset of 80 carcasses were evaluated for meat quality. Blood samples from 80 rabbits were analysed for haematological and biochemical parameters. A significant neutrophilia (P < 0.001), lymphocytopaenia (P < 0.001) and an increase in serum aspartate aminotransferase (AST) (P < 0.01), alanine aminotransferase (ALT) (P < 0.001) and creatine kinase (CK) activities (P < 0.001) were recorded in all rabbits after transport, independent of the loading method. A twofold increase in serum corticosterone concentration (6.23 vs. 14.88 ng/mL; P = 0.001) was observed in all rabbits following transport. Results suggest that the stress parameters analysed were more influenced by transport and handling itself rather than by the different loading methods. The results showed that there was no adverse effect of loading method on carcass traits. Furthermore, the stress condition evidenced by haematological and biochemical parameters prior to slaughter did not affect meat quality
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