ICA as a preprocessing technique for classification

In this paper we propose the use of the independent component analysis (ICA) [1] technique for improving the classification rate of decision trees and multilayer perceptrons [2], [3]. The use of an ICA for the preprocessing stage, makes the structure of both classifiers simpler, and therefore improves the generalization properties. The hypothesis behind the proposed preprocessing is that an ICA analysis will transform the feature space into a space where the components are independent, and aligned to the axes and therefore will be more adapted to the way that a decision tree is constructed. Also the inference of the weights of a multilayer perceptron will be much easier because the gradient search in the weight space will follow independent trajectories. The result is that classifiers are less complex and on some databases the error rate is lower. This idea is also applicable to regression

Percepción del dolor en pacientes postoperados de cirugía cardiaca

Pain is defined as an unpleasant sensory or emotional experience, associated with tissue damage, that is a reality linked to the surgical procedure and the postoperative period. Objective: Knowing the degree of pain experienced by patients after cardiac surgery, depending on the type of intervention they underwent, over the post-operative period in an intensive care unit (ICU). Method: Descriptive observational study. Pain was assessed by the visual analog scale (VAS), going from 0 to 10, thereby obtaining the first VAS1 assessment at 2 h post-extubation and every 8 hours thereafter up to 48 hours or until discharge to floor VAS7. It included patients having undergone cardiac surgery [valve surgery, bypass, combined procedure (including valve surgery and bypass) and mediastinitis]. Data were processed using Spss.v 20. Results: 120 patients 70 years old on average (standard deviation (SD): 13.3 years old) were included, out of which 70% were male. 40.8% of them had underwent bypass coronary revascularization. Patients subjected to the bypass technique showed an VAS1 mean value of 4.35 (SD: 2.45), unlike those subjected to valve surgery, who showed a mean value of 2.89 (SD: 2.27), those subjected to the combined procedure, who showed a mean value of 3.87 (SD: 2.90), and those with mediastinitis, who showed a mean value of 3.33 (SD: 3.51); (p < 0.031). 28.5% of patients had underwent revascularization (n = 49 ) by an internal mam mary artery (IMA) graft. These patients showed a mean value for VAS1 of 5.4 (SD: 1.89), unlike those who had underwent a combined procedure [IMA and saphenous vein (SV)], who showed a mean value of 3.9 (SD: 2.6), and those who had underwent a SV procedure , who showed a mean value of 3.5 (SD: 2.1); (p < 0.045). Conclusions: Patients having underwent bypass and IMA procedures perceive more pain than in other cardiac surgery and graft interventions

A digital holography technique for generating beams with arbitrary polarization and shape

A method for generating beams with arbitrary polarization and shape is proposed. Our design requires the use of a Mach-Zehnder set-up combined with translucent liquid crystal displays in each arm of the interferometer; in this way, independent manipulation of each transverse beam components is possible. The target of this communication is to develop a numerical procedure for calculating the holograms required for dynamically encode any amplitude value and polarization state in each point of the wavefront. Several examples demonstrating the capabilities of the method are provided.

Process variability-aware proactive reconfiguration technique for mitigating aging effects in nanos scale SRAM lifetime

Postprint (published version)

Acute Infection in Total Knee Arthroplasty: Diagnosis and Treatment

Infection is one of the most serious complications after total knee arthroplasty (TKA). The current incidence of prosthetic knee infection is 1-3%, depending on the series(.) For treatment and control to be more cost effective, multidisciplinary groups made up of professionals from different specialities who can work together to eradicate these kinds of infections need to be assembled. About the microbiology, Staphylococcus aureus and coagulase-negative staphylococcus were among the most frequent microorganisms involved (74%). Anamnesis and clinical examination are of primary importance in order to determine whether the problem may point to a possible acute septic complication. The first diagnosis may then be supported by increased CRP and ESR levels. The surgical treatment for a chronic prosthetic knee infection has been perfectly defined and standardized, and consists in a two-stage implant revision process. In contrast, the treatment for acute prosthetic knee infection is currently under debate. Considering the different surgical techniques that already exist, surgical debridement with conservation of the prosthesis and polythene revision appears to be an attractive option for both surgeon and patient, as it is less aggressive than the two-stage revision process and has lower initial costs. The different results obtained from this technique, along with prognosis factors and conclusions to keep in mind when it is indicated for an acute prosthetic infection, whether post-operative or haematogenous, will be analysed by the authors.