Circuits and systems education: viewpoint of GOLD and industry

This paper discusses Circuits and Systems (CAS) education, its strengths and shortcomings, and areas that need improvement from the perspective of two GOLD (graduates of the last decade) members and one industry member. The GOLD members highlight the need for hardware experiments, and active education methods such as self-learning through practices, and the importance of lab work to relate theory to practice, and also discuss the impact of new emerging technologies on educational reforms, also suggesting ways to get industry involved in the formulation of a new multidiscipline education curriculum. The GOLD members also discuss the impact of globalization on the CAS education in less- developed countries and the role of the IEEE CAS Society on the subject matter. The author from industry discusses the importance of CAS education, and contrary to the general belief, points out the importance of understanding the fundamentals of electrical engineering in industry. The author also discusses the importance of being flexible in a work environment, and establishing a broad knowledge in engineering to have a positive impact in the company.     

Quality characteristics of minimally processed leek packaged using different films and stored in lighting conditions

Since minimal processing of vegetables does not impede their capacity to react to external stimuli, this work sought to study the effect of lighting on minimally processed leek during storage. White and green cuts were processed separately and packaged using films with different permeability: a totally permeable PVC film and two P-Plus films: P-Plus 120 and P-Plus 90, with O₂ permeability of 8000 and 5000 cm³ m⁻² 24 h⁻¹ atm⁻¹ at 25 °C, respectively. All the packaged leek was stored at 4 °C for more than 26 days in two different conditions: in complete darkness and in light. Lighting caused an increase in stomatal aperture and respiratory rate. Thus, the white cut achieved atmospheres with higher CO₂ (10%) and lower O₂ (12%) content than samples packed in the same film kept in the dark. The green cut saw respiratory activity compensated by photosynthesis, and the atmosphere composition remained similar to atmospheric conditions until day 18. Lighting also affected the colour, accelerating the changes in appearance. Exposure to light had a negative effect on the quality parameters.     

Estimating crude cumulative incidences through multinomial logit regression on discrete cause-specific hazards

In the presence of competing risks, the estimation of crude cumulative incidence, i.e. the probability of a specific failure as time progresses, has received much attention in the methodological literature. It is possible to estimate crude cumulative incidence starting from models defined on cause-specific hazards or to adopt regression strategies modeling directly the quantity of interest. A generalized linear model based on discrete cause-specific hazard is used to obtain the crude cumulative incidence and its asymptotic variance. The model allows inference both on cause-specific hazard and on crude cumulative incidence in the presence of time dependent effects. Standard software can be used to compute all quantities of interest. A trial of chemoprevention of leukoplakia is considered for illustrative purposes, where different patterns of risk are suspected for the different causes of treatment failure.     

Characterisation of blends between poly(ε-caprolactone) and polysaccharides for tissue engineering applications

In this work, bioartificial binary blends between poly(ε-caprolactone) (PCL) and a polysaccharide (chitosan (CS) or starch (S)) with different contents of the natural polymer (5–30 wt.%) were produced. Melt-mixing and double-precipitation were the methods used for the obtainment of PCL/S and PCL/CS blends, respectively. Tubular scaffolds were produced from bioartificial blends by melt-extrusion. Physico-chemical characterisation was performed by differential scanning calorimetry analysis (DSC), thermogravimetry (TGA), scanning electron microscopy (SEM), infrared analysis (FTIR-ATR and micro-ATR mapping), atomic force microscopy (AFM) and stress–strain tests. Blends were not miscible, phase-separated systems, showing a homogeneous composition and morphology only at low polysaccharide content (≤ 10 wt.%). The biocompatibility of bioartificial guides was investigated by culturing NIH-3T3 mouse fibroblasts. Cells response showed the following order: PCL/S > PCL > PCL/CS. For each blend type, biocompatibility increased with decreasing the polysaccharide content. In vitro cell tests using S5Y5 neuroblastoma cells, carried out on the most biocompatible blends, assessed their absence of cytotoxicity towards these model cells of the nervous tissue. Results showed that blends with a low chitosan or starch content (≤ 10 wt.%) are promising for the regeneration of tissues requiring tubular scaffolds, such as the peripheral nerves.     

A heuristic approach for the max–min diversity problem based on max-clique

In this paper we discuss a heuristic approach for the solution to the max–min diversity problem. The approach relies on the equivalence between this problem and the classical max-clique: it solves different decision problems about the existence of cliques with a given size. The idea is rather simple but, according to the experiments and the comparison with the existing literature, appears as particularly promising and outperforms, both in quality and CPU time, the existing state of the art algorithms.     

Some comments on the numerical analysis of plates and thin-walled structures

The paper briefly reviews the theoretical analysis of plates structures that might exhibit multiple ‘loading paths’ and highlights the need for engineers using non-linear numerical modelling to be aware of the multi-mode phenomenon and to ensure that the modelling is set up in such a manner that the various ‘loading paths’ and possible changes of path would be incorporated in the modelling response. The paper presents a simple example of numerical analysis of thin-plate buckling that involves ‘coupled buckling modes’ and provides comments on suitable methods for defining in a simple and straightforward way the numerical modelling that could ensure that results from computer analysis describe the physically correct relationship between applied loadings and deformations of thin-walled structural components.