4,409 research outputs found
Synchronous Context-Free Grammars and Optimal Linear Parsing Strategies
Synchronous Context-Free Grammars (SCFGs), also known as syntax-directed
translation schemata, are unlike context-free grammars in that they do not have
a binary normal form. In general, parsing with SCFGs takes space and time
polynomial in the length of the input strings, but with the degree of the
polynomial depending on the permutations of the SCFG rules. We consider linear
parsing strategies, which add one nonterminal at a time. We show that for a
given input permutation, the problems of finding the linear parsing strategy
with the minimum space and time complexity are both NP-hard
TSA infrared measurements for stress distribution on car elements
Abstract. Because of the continuous evolution of the market in terms of quality and performance, the car production industry is being subjected to more and more pressing technological challenges. In this framework the use of an advanced measurement technique such as thermoelasticity allows the engineers to have a fast and reliable tool for experimental investigation, optimization and validation of the finite element method (FEM) of those critical parts, such as parts of car-frame tables (Marsili and Garinei, 2013; Ju et al., 1997). In this work it is shown how the thermoelastic measurement technique can be used to optimize a Ferrari car frame, as a method of experimental investigation and as a technique of validation of numerical models.The measurement technique developed for this purpose is described together with the calibration method used in the test benches normally used for fatigue testing and qualification of this car's components. The results obtained show a very good agreement with FEM models and also the possibility of experimentally identifying the concentration levels of stress in critical parts with a very high spatial resolution and testing the effective geometry and material structure
Role of perfusion machines in the setting of clinical liver transplantation. A qualitative systematic review
Growing enthusiasm around machine perfusion (MP) in clinical liver transplantation (LT) may be the preamble for standardized practice to expand the donors' pool. The present systematic review investigated all the liver transplantations performed using grafts treated with MP. A systematic review of 309 papers was performed. Eventually, 27 articles were enrolled for the study. A total number of 173 cases was reported. Only 12 cohort studies were identified: the remaining ones were case reports or case series. Hypothermic machine perfusion was performed in 102 (59.0%), normothermic machine perfusion in 65 (37.6%), and controlled oxygenated rewarming in the remaining 6 (3.4%) cases. Donor characteristics, evaluation of graft quality and end-points were not homogeneous among the studies. Overall, post-LT results were excellent, with 1.2 and 4.0% of patients experienced primary non-function and ischemic-type biliary lesions, respectively
Eimeria legionensis and Eimeria kofoidi (Apicomplexa: Eimeriidae) infection and associated lesions in naturally infected red-legged partridges (alectoris rufa)
With the aim to identify the Eimeria species responsible for coccidiosis in 50 deceased red-legged partridges (Alectoris rufa), individual faecal samples were collected, dissolved in 2.5% K2Cr2O7 solution and maintained at room temperature to allow sporulation of the oocysts. Morphology and dimensions of sporulated oocysts were microscopically evaluated. To assess Eimeria intestinal localisation, faecal samples and scrapings taken from the different intestinal segments of each deceased animal were examined by fresh smears and flotation test, while the intestines were examined for gross lesions, then fixed in 10% formalin and processed for histopathological analysis. From scrapings and morphological analysis, Eimeria kofoidi and Eimeria legionensis were identified in the small intestine and in the caecum and colon, respectively. Histopathological analysis confirmed the presence of two distinct Eimeria species. In particular, E. kofoidi macrogamonts were found in epithelial cells of jejunum and ileum, between the basal lamina and the nucleus of the infected intestinal cells. This latter was flattened and displaced above. E. legionensis macrogamonts were instead found localised between the nucleus and the luminal surface of the infected caeca and colonic cells and these macrogamonts were larger than those of E. kofoidi. Chronic enteritis and severe displacement of the deep crypts of the small intestine, large areas of caeca and colonic epithelial necrosis associated to thickened wall and mononuclear cells infiltration diffused in a transmural manner, were the main histopathological lesions
Food networks: collective action and local development. The role of organic farming as boundary object
This article aims at analyzing the innovation potential of a local food network, which sees different actors that cooperate to build a local organic food production-provision system and progressively develop a broader mobilization on food issues, health and sustainability. The case analyzed is that of Crisoperla, an association located in Italy, between Tuscany and Liguria, which involves organic farmers, social farming and fishermen cooperatives, consumers’ groups and association and agronomists. The analysis is based on the empirical data collected in the 3-year European project SOLINSA (FP7, 2011–2014). The focus is on the role of organic farming and organic food as a boundary object, a binder element around which actors involved work in order to develop common visions, languages and goals and organize their activities. These processes are, in fact, at the basis of the organizational consolidation of the association as well as of the growth of its political awareness and its willingness and capacity to interact with the outside both at local and higher levels
Gender and Age Related Effects While Watching TV Advertisements: An EEG Study
The aim of the present paper is to show how the variation of the EEG frontal cortical asymmetry is related to the general appreciation perceived during the observation of TV advertisements, in particular considering the influence of the gender and age on it. In particular, we investigated the influence of the gender on the perception of a car advertisement (Experiment 1) and the influence of the factor age on a chewing gum commercial (Experiment 2). Experiment 1 results showed statistically significant higher approach values for the men group throughout the commercial. Results from Experiment 2 showed significant lower values by older adults for the spot, containing scenes not very enjoyed by them. In both studies, there was no statistical significant difference in the scene
relative to the product offering between the experimental populations, suggesting the absence in our study of a bias towards the specific product in the evaluated populations. These evidences state the importance of the creativity in advertising, in order to attract the target population
Exploiting Multiple Priors for Neural 3D Indoor Reconstruction
Neural implicit modeling permits to achieve impressive 3D reconstruction
results on small objects, while it exhibits significant limitations in large
indoor scenes. In this work, we propose a novel neural implicit modeling method
that leverages multiple regularization strategies to achieve better
reconstructions of large indoor environments, while relying only on images. A
sparse but accurate depth prior is used to anchor the scene to the initial
model. A dense but less accurate depth prior is also introduced, flexible
enough to still let the model diverge from it to improve the estimated
geometry. Then, a novel self-supervised strategy to regularize the estimated
surface normals is presented. Finally, a learnable exposure compensation scheme
permits to cope with challenging lighting conditions. Experimental results show
that our approach produces state-of-the-art 3D reconstructions in challenging
indoor scenarios.Comment: Accepted at the British Machine Vision Conference (BMVC) 202
Imaging follow-up after liver transplantation
Liver transplantation (LT) represents the best treatment for end-stage chronic liver disease, acute liver failure and early stages of hepatocellular carcinoma. Radiologists should be aware of surgical techniques to distinguish a normal appearance from pathological findings. Imaging modalities, such as ultrasound, CT and MR, provide for rapid and reliable detection of vascular and biliary complications after LT. The role of imaging in the evaluation of rejection and primary graft dysfunction is less defined. This article illustrates the main surgical anastomoses during LT, the normal appearance and complications of the liver parenchyma and vascular and biliary structures.Liver transplantation (LT) represents the best treatment for end-stage chronic liver disease, acute liver failure and early stages of hepatocellular carcinoma. Radiologists should be aware of surgical techniques to distinguish a normal appearance from pathological findings. Imaging modalities, such as ultrasound, CT and MR, provide for rapid and reliable detection of vascular and biliary complications after LT. The role of imaging in the evaluation of rejection and primary graft dysfunction is less defined. This article illustrates the main surgical anastomoses during LT, the normal appearance and complications of the liver parenchyma and vascular and biliary structures
Innovation for sustainable agriculture: perspectives and potentials of learning processes in two case studies in Italy
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