1,354,093 research outputs found
La contabilità dell’arte. Gli autori di opere creative e il mercato artistico del XVII secolo nelle carte dell’Archivio Storico del Pio Monte della Misericordia
No full textDesign and Test of a Compound Persistent-Pulsed Magnet for Fast Field Cycling NMR
No full textIn order to investigate the possibility of using superconducting
magnets for Fast Field Cycling (FFC) NMR Relaxometry,
a NbTi magnet able to achieve high field variation rates in a
constant background field has been designed and tested. The design
layout consists in an outer superconducting magnet working
in persistent mode and an inner superconducting magnet working
in pulsed mode.
The layout of the inner magnet has been optimized taking into
account field strength, field homogeneity, stray field and inductive
coupling with outer magnet. A demonstration pulsed magnet
has been tested in a background field, achieving the main desired
working features
Advantages of myocardial revascularization after admission for critical limb ischemia in diabetic patients with coronary artery disease : data of a cohort of 564 consecutive patients
No full textAIM: To evaluate the survival benefit from myocardial revascularization in diabetic patients with critical limb ischemia and coronary artery disease (CAD) in a consecutive series of 564 diabetic patients hospitalized from 1999 to 2003 and followed up until December 2005. METHODS: Three hundred and thirteen patients had a history of CAD, 60 of them (19.2%) with previous myocardial revascularization. Sixty-one patients with an ejection fraction of 40% or less underwent subsequent myocardial revascularization. Five hundred and fifty-seven patients (98.8%) were followed up until December 2005, including 310 of the 313 patients with a history of CAD. RESULTS: One hundred and ten patients died because of CAD, 25 of the 251 patients without a history of CAD and 85 of the 313 patients with a history of CAD. Specifically, 74 (86.9%) of these 85 deaths occurred in the 192 patients without previous myocardial revascularization, nine (10.7%) in the 60 patients with previous myocardial revascularization, and two (2.4%) in the 61 patients in whom myocardial revascularization was performed after hospital admission for critical limb ischemia. The Cox model showed significant hazard ratio for mortality associated with age [hazard ratio 1.06 for 1 year, P = 0.003, confidence interval (CI) 1.02-1.09], history of CAD (hazard ratio 2.16, P < 0.001, CI 1.53-3.06), dialysis (hazard ratio 3.52, P < 0.001, CI 2.08-5.97), and impaired ejection fraction (hazard ratio 1.08 for one point percentage, P < 0.001, CI 1.05-1.09). Myocardial revascularization appeared to have a protective role: hazard ratio 0.29, P < 0.001, CI 0.33-0.93. CONCLUSION: Paying attention to CAD in diabetic patients during their hospitalization for critical limb ischemia is useful for a subsequent myocardial revascularization, and it may increase survival in these patient
HIGH DENSITY MgB2 BULK MATERIALS OF DIFFERENT GRAINS SIZE: SUPERCURRENTS INSTABILITY AND LOSSES IN VARIABLE MAGNETIC FIELDS
No full textThe bulkMgB2 material shows very promising characteristics to be applied in many AC devices, i.e. as electric motors, as magnetic field screening apparatus or as variable inductor or resistor for Fault Current Limitation. In all these cases the evaluation of supercurrents persistency and of the AC losses represents the first practical issue to be addressed. We report on the evaluation of these characteristics on very high densityMgB2 bulk materials, obtained by reactive liquid Mg infiltration of Boron powders preform. Varying the granularity of the original Boron powders, bulks of very different grains size distribution are produced that show different current carrying capability in magnetic field and temperature, indicating a different flux structure and dynamics. Performing AC susceptibility analysis in the low frequency range, the losses have been evaluated on several shapes of the probe materials from the cylindrical one to the slab one type and for several temperatures below Tc. For ring type samples the screening effect of the superconducting currents has been evaluated, in presence of static and variable magnetic fields. The results have been interpreted in term of the critical state model, evidencing the large effects of the thermal instability erasing from the thickness of the samples
Incidence of critical limb ischemia and amputation outcome in contralateral limb in diabetic patients hospitalized for unilateral critical limb ischemia during 1999-2003 and followed-up until 2005
No full textWe studied the incidence of critical limb ischemia (CLI) and amputation outcome of the contralateral limb in 533 diabetic patients hospitalized in our diabetic foot centre because of CLI from 1999 to 2003 and followed-up until 2005. The cumulative incidence rate during the 6-year period reached 49.8% (CI confidence interval=40.6-59.6). All patients underwent arteriography and in 181 (98.4%) the revascularization was performed without different feasibility (p=0.077) compared to that (95.3%) in the initial patients. The severity of lesion evaluated with Wagner grade was lower (chi(2)=33.5, p<0.001) and also the frequency of midfoot and above-the-ankle amputations was lower (p<0.001 and p=0.022, respectively) in contralateral patients. There was no evidence from the logistic analysis to support the association between any of the investigated variables and incidence of CLI in the contralateral limb. Over a 6-year period, almost 50% of the diabetic patients with unilateral CLI developed a CLI in the contralateral limb: however, both severity of foot lesion and amputation level was significantly lower. This fact can be due to prompt therapeutic interventions, made possible thanks to an increased patient awareness acquired by training during the treatment of the unilateral limb
Normal zone propagation in a MgB2 conduction cooled test magnet
No full textIn order to investigate the quench behavior of conduction cooled magnets, a 100 mm inner bore diameter, 0.84 T at 20 K magnet has been built and tested. The test magnet consists of 4 double pancakes wound with the tape produced by Columbus. Each coil is cooled by means of a 2 mm thick copper disk placed during winding at the middle of the double pancake; after winding the double pancakes have been separately epoxy impregnated. Several experiments have been per- formed inducing a local transition in the coil by means of a con- trolled heater placed on the double pancake surface. The propagation of the normal zone has been monitored by means of 8 voltage probes positioned along the tape during coil manufacturing. Each voltage probe detects the voltage drop across a tape length of 30 mm. The experiments have been performed at different temperatures while keeping the magnet current constant during quench. In the paper we report an analysis of the quench propagation velocity measurements and a numerical investigation of the thermal and electrical behavior of the magnet
The role of early surgical debridement and revascularization in patients with diabetes and deep foot space abscess : retrospective review of 106 patients with diabetes
No full textOne hundred-six patients underwent emergency debridement of a deep foot space abscess. While 43 patients were admitted after an outpatient visit with immediate surgical debridement (group A), 63 patients were transferred from other hospitals after a mean stay of 6.2 ± 7.5 days without debridement (group B). No significant differences were observed in the demographic and clinical features between the 2 groups, except for the following differences in group B: higher blood glucose level on admission (P = .015), lower serum albumin level (P = .005), and a more frequent extension of the infection to the heel (P = .005). Eradication of the infection was obtained in group A without amputation in 9 patients, with an amputation of 1 or more rays in 21, with metatarsal amputations in 12, and with a Chopart amputation in 1. In group B, incision and drainage alone were performed in 4 patients, amputation of 1 or more rays in 21, metatarsal amputations in 10, Chopart amputations in 23, and an above-the-ankle amputation in 5. The amputation level was significantly more proximal in group B (χ 2 = 24.4, P < .001). There was no significant difference in the presence of peripheral arterial occlusive disease between the 2 groups (P = .841). Regression logistic analysis showed a significant relationship between the amputation level and the number of days elapsed before debridement (odds ratio, 1.61; P = .015; confidence interval, 1.10-2.36), but not with the presence of peripheral occlusive disease (odds ratio, 1.73; P = .376; confidence interval, 0.29-15.3). These data show that a delay in the surgical debridement of a deep space abscess increases the amputation level. Accuracy in the diagnosis of peripheral occlusive disease and immediate revascularization yield similar outcomes in patients with or without peripheral occlusive disease
LuckyMera: a modular AI framework for building hybrid NetHack agents
No full textIn the last few decades we have witnessed a significant development in Artificial Intelligence (AI) thanks to the availability of a variety of testbeds, mostly based on simulated environments and video games. Among those, roguelike games offer a very good trade-off in terms of complexity of the environment and computational costs, which makes them perfectly suited to test AI agents generalization capabilities. In this work, we present LuckyMera, a flexible, modular, extensible and configurable AI framework built around NetHack, a popular terminal-based, single-player roguelike video game. This library is aimed at simplifying and speeding up the development of AI agents capable of successfully playing the game and offering a high-level interface for designing game strategies. LuckyMera comes with a set of off-the-shelf symbolic and neural modules (called "skills"): these modules can be either hard-coded behaviors, or neural Reinforcement Learning approaches, with the possibility of creating compositional hybrid solutions. Additionally, LuckyMera comes with a set of utility features to save its experiences in the form of trajectories for further analysis and to use them as datasets to train neural modules, with a direct interface to the NetHack Learning Environment and MiniHack. Through an empirical evaluation we validate our skills implementation and propose a strong baseline agent that can reach state-of-the-art performances in the complete NetHack game. LuckyMera is open-source and available at https://github.com/Pervasive-AI-Lab/LuckyMera
Performance Evaluation for a HTS Transformer
No full textThe adoption of High Temperature Superconductors
(HTS) tapes is becoming a suitable and interesting alternative to copper for windings in transformers, thanks to the improvement
in performance and the lowering of costs. Of course, optimized designs, different with respect to usual layouts, must be considered,
due to the additional requirements of HTS tapes, such as minimization of orthogonal magnetic fields and consideration of additional losses in the HTS. In the framework of a scientific cooperation
among some Italian Universities and private companies, a test model for a 10KVA transformer with HTS secondary windings has
been developed, and validated against a demonstrative prototype, manufactured during the project. In the paper, the device model
performance is assessed, with particular care to the HTS losses modeling, and some comparisons to the experimental results are
presented
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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