Preliminary study of saffron (Crocus sativus L. stigmas) color extraction in a dairy matrix

Saffron spice has been used for decades as an ingredient in many dairy products but changes in its coloring properties related to milk characteristics have not been paid appropriate attention. Saffron color was studied in ewes’ milk at different fat levels and saffron concentrations using tristimulus colorimetry. In order to evaluate saffron extraction, different temperatures and extraction times were tested. Color changes were demonstrated to be statistically significant when increasing the fat content in milk, as well as saffron concentration. The higher milk fat content, turned the extracts brighter and yellower, while less red and vivid, opposite to results obtained by increasing saffron concentration. Extraction time was not significant for color extraction. Milk extracts resulted slightly brighter and yellower when increasing temperature, probably due to crocetin esters degradation or isomerization from trans to cis configuration. Temperatures between 37 and 70 °C are recommended to avoid structural changes in milk or saffron. Color changes could be due to interactions mediated by phospholipids between milk fat globules and crocetin esters, as well as minor saffron carotenoids.     

On the influence of the shear deformation and boundary conditions on the transverse vibration of multi-walled carbon nanotubes

The vibrational properties of multi-walled carbon nanotubes (MWCNTs) are studied, especially the influence of the shear deformation and the boundary conditions on the non-coaxial frequencies. A high order continuum beam model is proposed, which can be applied to study the transverse vibrations of MWCNTs, including those that could have initial deformations due to defects or external actions. Using the model it was found that the non-coaxial intertube frequencies are independent of the shear deformation and the boundary conditions. This result is important considering that the concentric structure of MWCNTs is a crucial geometrical characteristic and a non-coaxial vibration would affect their electronic and optical properties.     

Spatial distribution of dry matter in yellow fleshed cassava roots and its influence on carotenoid retention upon boiling

Understanding retention of carotenoids after different processing methods is important. This study was conducted to quantify dry matter content and carotenoids found in different sections of the cassava roots from six clones and to assess true retention of carotenoids after 30 min of boiling. Retention was quantified in normalized prisms taken from proximal, central and distal sectors of the root. Dry matter content (DMC) was measured along and across the roots and varied from 14.1 to 51.0%. DMC tended to be lower at the center of the root and in distal sections. DMC affected the homogeneity of the food matrix and, therefore, contributed in spatial variation in retention of carotenoids. Average true retention (dry matter basis) was 86.6% and ranged from 76.0 and 96.7% (averages per clone and section of the root, respectively). Retention was positively associated with carotenoid content in unprocessed samples, although the relationship was weak. The study shows that during boiling weight of samples changed from slight losses to gains of up to 40% (depending on original DMC of the uncooked root), resulting in an “apparent dilution” of the carotenoids. Results suggested the occurrence of some isomerization. All-trans β-carotene losses (13%) were partially explained by increases in the 13-cis (34%) and 15-cis (8%) isoforms, as well as lixiviation (< 1%) into the boiling water.     

A Posteriori Analysis of a Positive Streamwise Invariant Discretization of a Convection-Diffusion Equation

We consider the finite element discretization of a convection-diffusion equation, where the convection term is handled via a fluctuation splitting algorithm. We prove a posteriori error estimates which allow us to perform mesh adaptivity in order to optimize the discretization of these equations. Numerical results confirm the interest of such an approach.     

Ranking Star-Shaped Valued Mappings with Respect to Shape Variability

The study of shapes is a difficult topic, but it is becoming more and more important as computer vision techniques are already crucial in many research fields. Concretely, the variability of shapes is the basis for many criteria of symptom definition in medical diagnosis. This article introduces a stochastic order to address the variability of star-shaped sets. The main properties of the order are analyzed. An example of an application to hypothesis testing in medical diagnosis is also provided. Namely, we study if there are significant differences between healthy and diseased corneal endothelia with respect to cell shapes by means of ocular images.     

Simplified EDF characterization method for WDM applications

Abstract

A new, simple EDF characterization method is presented. Departing from well-known equations, some approximations, applicable in WDM working conditions, are introduced. Thanks to them, the number of active parameters necessary to describe the EDF behaviour is sensibly reduced. Afterwards, a simple experiment to find such parameters is proposed. Finally, the characterization method is applied to an EDF and the parameters′ values obtained are used to predict gain results. A good agreement between these predictions and experimental data is observed.     

Metaheuristic optimization frameworks: a survey and benchmarking

This paper performs an unprecedented comparative study of Metaheuristic optimization frameworks. As criteria for comparison a set of 271 features grouped in 30 characteristics and 6 areas has been selected. These features include the different metaheuristic techniques covered, mechanisms for solution encoding, constraint handling, neighborhood specification, hybridization, parallel and distributed computation, software engineering best practices, documentation and user interface, etc. A metric has been defined for each feature so that the scores obtained by a framework are averaged within each group of features, leading to a final average score for each framework. Out of 33 frameworks ten have been selected from the literature using well-defined filtering criteria, and the results of the comparison are analyzed with the aim of identifying improvement areas and gaps in specific frameworks and the whole set. Generally speaking, a significant lack of support has been found for hyper-heuristics, and parallel and distributed computing capabilities. It is also desirable to have a wider implementation of some Software Engineering best practices. Finally, a wider support for some metaheuristics and hybridization capabilities is needed.