Search

Abstract:In this paper I discuss Lorenzo Valla’s criticism of the traditional Square of Opposition displayed in the second book of the Dialectica. I show that, according to Valla, the opposition rules of the propositions must take into account both common speeches and the correct use of Latin language, not the formal link occurring between the parts of propositions. In Valla’s perspective, this theoretical change is carried out through rhetoric and philology, and it involves a reassessment of the arts of the trivium. As regards this topic, I argue that Valla aims niether to reduce dialectic to rhetoric nor to replace the former with the latter, but rather to establish some rhetorical principles as a better-suited way to set the opposition rules, because they take into account the linguistic context in which these rules apply.

In this paper I discuss Lorenzo Valla's criticism of the traditional Square of Opposition displayed in the second book of the Dialectica. I show that, according to Valla, the opposition rules of the propositions must take into account both common speeches and the correct use of Latin language, not the formal link occurring between the parts of propositions. In Valla's perspective, this theoretical change is carried out through rhetoric and philology, and it involves a reassessment of the arts of the trivium. As regards this topic, I argue that Valla aims niether to reduce dialectic to rhetoric nor to replace the former with the latter, but rather to establish some rhetorical principles as a better-suited way to set the opposition rules, because they take into account the linguistic context in which these rules apply.

The aim of this work is the numerical assessment of the ultimate behaviour of aluminium alloy beams subjected to non-uniform bending. An extensive numerical analysis has been performed by means of FE code ABAQUS with reference to RHS sections considering different values of the main geometrical and mechanical parameters. In particular, regarding the geometrical parameters the flange slenderness, the flange-to-web slenderness ratio and the moment gradient parameter have been considered. In particular, their influence on the ultimate behaviour of such beams has been investigated by adopting the material constitutive law proposed by Eurocode 9 based on the Ramberg-Osgood model. The investigations concern these parameters considered separately as well as their interaction. The results are herein reported with reference to temper T6 and show the importance of the investigated parameters on the buckling strength and the rotational capacity of aluminium alloy beams. Temper T6 gives rise to a quite low hardening compared to temper T4, which is analysed in a companion paper.

The aim of this work consists in the numerical assessment of the moment-rotation behaviour of RHS aluminium alloy beams subjected to non-uniform bending through an extensive parametric analysis performed by means of FE code ABAQUS investigating the influence of the main geometrical and mechanical parameters. In particular, the influence of the flange slenderness, web stiffness and moment gradient are investigated by adopting the constitutive law proposed by Eurocode 9 based on the Ramberg-Osgood model whose shape factor characterise the hardening behaviour of the material. The investigations concern these factors considered separately as well as their interaction. The results are herein reported with reference to temper T4 and show the importance of some of the investigated parameters on both buckling strength and rotation capacity of aluminium alloy beams.

The aim of this work is the development of an empirical relationship for evaluating the rotation capacity of RHS aluminium alloy beams, for temper T4 and T6. The proposed relationships are based on the numerical results coming from an extensive parametric analysis performed by means of FE code ABAQUS for different materials, which gain insight into the influence of all the geometrical and mechanical parameters affecting the ultimate behaviour. In particular, the influence of the materials strain hardening, flange slenderness, web stiffness, shape factor and moment gradient the on the plastic behaviour of such beams has been investigated. Successively, by means of monovariate and multivariate non linear regression analyses, empirical relationships are provided in order to predict the rotation capacity of RHS aluminium alloy beams starting from their geometrical and mechanical properties. This paper is focused on this issue.

Reinforced concrete structures are generally affected by degradation phenomena, which results in a time variability in strength and stiffness beyond the baseline conditions which are assumed in structural design, in particular when the concrete is exposed to an aggressive environment. Therefore, structural safety should realistically be considered time-variant. This paper provides a probabilistic approach to predict the time-evolution of the mechanical and geometrical properties of a reinforced concrete structural element (i.e., bridge pier) subjected to corrosion-induced deterioration, due to diffusive attack of chlorides, in order to evaluate its service life. The proposed model is based on Monte Carlo simulations in order to evaluate time variant axial force-bending moment resistance domains, with the aim to estimate the time-variant reliability index. Finally, an application to estimate the expected lifetime of a deteriorating reinforced concrete bridge pile is proposed.

Structural safety of existing buildings near deep excavations is evaluated by computing exceeding probabilities of different damage criteria within a simplified probabilistic methodology based on monovariate or multivariate probabilistic analyses employing the results of a numerical model of the boundary value problem. Different limit domains, defined on one or more deformation parameters and associated to limit states, are used to contemplate: the type of the structural system (i.e., reinforced concrete or masonry buildings); the foundation typology (i.e., strip/raft or pad foundations). The sensitivity analysis is developed considering the design of a new underground station in Naples (Italy).

• During a 50-month period, we identified 91 episodes of fungal infection in 72 liver transplant recipients (23.8%). Candida species accounted for 83.5% of cases. Clinical patterns of fungal infections included disseminated infection (19), peritonitis (17), pneumonitis (15), multiple sites of colonization (13), fungemia (11), and other sites (16). The diagnosis of fungal infection was usually made in the first 2 months (84.7% of cases), at a mean time of 16 days after transplantation. Risk factors for fungal infections included retransplantation, Risk score, intraoperative transfusion requirement, urgent status, Roux limb biliary reconstruction (in adults), steroid dose, bacterial infections and antibiotic therapy, and vascular complications. Fungal infections were successfully treated with amphotericin B in 63 cases (74.1%) but were associated with diminished patient survival (50% vs 83.5%). Fungal infection is a frequent source of early morbidity and can be related to well-defined risk factors, suggesting the need for effective prophylaxis.(Arch Surg. 1991;126:149-156)

Abstract: Tissue CEA, TPA, and CA 19.9 concentrations from samples of surgical specimens were measured in 47 evaluable colorectal cancer patients (median follow-up, 20 months, 13 recurrences) and correlated with individual patient follow-up status. The quantitative method appeared to be sensitive, easily reproducible, and standardizable. The tissue marker concentration was analyzed by means of the multivariate discriminant analysis, to evaluate the risk of relapse in each patient; the tumor CEA (CEAT) showed the best discriminant capacity (P=.005). The relative Fisher function provided a reliable prognostic patient index, independently of other recognized prognostic factors (Dukes' stage and cellular differentiation grade). The Cox model showed a statistical significance analyzing the tumor (T) and healthy mucosa (M) CEA values (P=.001 andP=.006, respectively). The combination of these two variables allowed for identification of three classes of patients according to CEA T and M threshold values of 216 and 85 ng/mg of protein, respectively, and different disease-free curves were obtained for each group. The two-year disease-free rate was 81 percent for patients with low values of both CEA T and M, and 21.4 percent for the group with both values above these thresholds (P=.0008). In the third class (CEA T or M higher than the reported cut-off levels), the two-year disease-free rate was 65.9 percent.

The aim of the study was to evaluate in our institute the technique of sentinel node (SN) identification and biopsy in the surgical treatment of early breast cancer. Between June 1998 and November 1999 54 patients (age range, 31–75 years) where studied. Inclusion criteria were age less than 75 years, indication for conservative surgery, absence of palpable axillary nodes, Karnofksy index >70. Lymphoscintigraphy was performed 16–18 hours prior to surgery, following injection of 0.1–0.2 mL of 99mTc-Nanocoll: the administered activity was 3–4 MBq in group A (44 pts) and 7–8 MBq in group B (10 pts). The colloids were administered by transdermal supralesional injection in 49 patients with palpable nodules and by intraparenchymal ultrasound-guided injection in five patients with non-palpable nodules. Planar projections were performed starting from the 5th until the 80th min (or 180th in the event of late migration). In 10 patients further projections were acquired 14–18 h following tracer administration. All nodes identified by gamma probe (MR 100 Pol. Hi. Tech) were histologically evaluated by immunohistochemistry and standard histology. Scintigraphic visualization of the SN was obtained in 49 patients: in 38 of these patients there was only one SN while in 11 patients there were two or three SNs. The delayed scan made in 10 patients did not show any further nodes. In all patients given US-guided perilesional injections migration was late (after at least 60 min). Our study confirms the validity of the scintigraphic procedure, its safety for patients and health care workers, and the feasibility of interdisciplinary collaboration.

The assessment of existing reinforced concrete structures is a critical aspect for engineers and practitioners. In particular, existing infrastructures, as bridges and viaducts, are extensively exposed to environmental actions, materials aging, degradation and variation of magnitude of traffic loads during their service life. Hence, to perform the assessment of existing structural systems assuming the same criteria conceived for the design (i.e., partial factor method - EN 1990) can result to be too conservative and, sometimes, leads to unnecessary and costly structural interventions. In this context, fib Bulletin 80 defines a new partial factor method suitable for the assessment of existing reinforced concrete structures and infrastructures accounting for their residual service life, information from in situ and laboratory tests, measurements of variable actions and reduced target reliability levels according to economical and human safety criteria. The methodologies proposed in fib Bulletin 80 have been applied to the assessment of an existing precast box section pre-stressed reinforced concrete bridge built in 90s and located in north of Italy. The results are compared to the outcomes from the assessment performed according to EN1990 and, finally, limits and advantages of fib Bulletin 80 methodologies are discussed.

In common practice and in design codes, the evaluation of laps and anchorages strength in reinforced concrete structures is performed by means of empirical or semi-empirical equations. These models couple the knowledge coming from both the experiments and the physical assumptions related to the actual resisting mechanism. In fib Model Code 2010 an efficient semi-empirical resisting model for the evaluation of laps and anchorages strength has been proposed. However, such kind of model should be calibrated referring to the levels of reliability required by the design codes in order to use it for design purposes and structural verifications. In the present paper, a consistent calibration procedure based on Monte Carlo method is used for the probabilistic assessment of the abovementioned semi-empirical model, accounting for both aleatory and epistemic uncertainties. Then, the design formulation is defined according to a specific level of reliability, and its application for the calculation of the required laps and anchorages length in reinforced concrete structures is commented. Finally, the comparison with the provisions of Eurocode 2 and fib Model Code 2010 is proposed and discussed.

The early detection of allograft rejection remains elusive after solitary pancreas transplantation PTX. We have previously described a modified technique of cystoscopic transduodenal PTX biopsy using the Biopty gun under ultrasound guidance. During the last 2 years, we performed 24 solitary PTXs with prospective protocol biopsy monitoring as well as biopsies performed whenever clinically indicated. The study group included 17 pancreas transplants alone, 6 sequential pancreas after kidney transplants, and 1 sequential pancreas after liver transplant. Five patients received pancreas retransplants. A total of 92 cystoscopically directed core PTX biopsies were performed, including 50 protocol biopsies mean 2.1 per patient. Protocol biopsies were performed at 1 month 19, 2 months 3, 3 months 20, 6 months 7, and 12 months 1 after PTX. Adequate PTX tissue for histopathologic examination was obtained in 49 cases 98. Biopsy findings included no rejection 34, mild rejection 13, pancreatitis 1, and cytomegalovirus infection 1. Overall, 15 of the 49 evaluable biopsies 31 had significant histopathologic findings. All but 1 of the cases of mild rejection were treated with bolus steroids. Eight of these patients subsequently developed recurrent biopsyproven rejection within 2 months 5 grafts were subsequently lost to rejection between 3 and 13 months after PTX. Three biopsy complications occurred 1 hematoma, 1 pancreatitis, and 1 ileus. Patient survival is 96 and PTX graft survival complete insulin independence is 75 after a mean followup of 15 months. In the remaining 42 clinically indicated biopsies, 3 were insufficient, 8 showed no rejection, and 31 79 had rejection. In half of these cases, the rejection was graded as moderate to severe. In conclusion, prospective monitoring with protocol PTX biopsies may result in the earlier detection of allograft rejection and have a direct effect on improving results after solitary PTX.