Distributed resource allocation in cognitive radio networks with a game learning approach to improve aggregate system capacity

This paper presents a game theoretic solution for joint channel allocation and power control in cognitive radio networks analyzed under the physical interference model. The objective is to find a distributed solution that maximizes the network utility, defined with different criteria, with limited information. The problem is addressed through a non-cooperative game based on local information. Although the existence of a pure Nash Equilibrium cannot be assured for this game, simulation results show that it exists with high probability and with a performance similar to that of a potential game, where each player requires overall network information. The obtained results are compared with a centralized heuristic genetic algorithm to show the correctness of the proposals. From this point, utility functions for the local game are modified to restrict the transmitted power to drive the solution to a more cooperative approach. To overcome the convergence limitations of the local game, no-regret learning algorithms are used to perform the joint channel and power allocation. These algorithms provide stable mixed strategies in any scenario with even better global performance. This opens an interesting perspective to develop realistic protocols based on the modeled interactions and increases the adaptability to perform efficient opportunistic spectrum access.     

Evaluation of table olive by‐product as a source of natural antioxidants

The main by‐product from the table olive canning industry is the stone with some residual olive flesh. The purpose of this study was to evaluate the composition – phenolic compounds (hydroxytyrosol, tyrosol and oleuropein) and tocopherol – and the antioxidant activity in different fractions (flesh, stone and seed) from the table olive by‐product and the whole by‐product. The highest amounts of phenolic compounds (1710.0 ± 33.8 mg kg^?1) as well as the highest antioxidant activity (8226.9 ± 9.9 hydroxytyrosol equivalents mg kg^?1) were obtained in the seed. The highest amounts of hydroxytyrosol (854.8 ± 66.0 mg kg^?1) and tyrosol (423.6 ± 56.9 mg kg^?1) were found in the whole by‐product from the pepper stuffed olives, while the stone without seed had the maximum oleuropein content (750.2 ± 85.3 mg kg^?1). α‐Tocopherol values were between 79.8 ± 20.8 mg kg^?1 in the seed of the olive stone and 6.2 ± 1.2 mg kg^?1 in the whole by‐product from the anchovy‐stuffed olives. In light of the results obtained, it would seem possible to use table olive by‐product as a source of natural antioxidants in foods, cosmetics or pharmaceutical products, thus contributing to diminishing the environmental impact of table olive by‐product and to its revalorisation.     

Endogenous Proteases in Pacific Whiting (Merluccius productus) Muscle as A Processing Aid in Functional Fish Protein Hydrolysate Production

A fish protein hydrolysate (FPH) from Pacific whiting (Merluccius productus) muscle was produced by autolysis of a minced homogenate (8% protein) at pH 7.0 and 60°C, where maximum endogenous proteolytic activity was detected. FPH production was controlled by the pH stat method, yielding a 4.43% degree of hydrolysis after 1 h of autolysis. Upon autolytic processing, 28.9 ± 0.7% of the total protein was found in the soluble fraction. FPH was 100% soluble at pH 7.0 and 10.0 and was less soluble at pH 4 (82.5%, P ≤ 0.05). FPH showed better emulsifying properties than sodium caseinate (SCA) at pH 4.0 (P ≤ 0.05), but had a lower foaming capacity (P ≤ 0.05) than bovine albumin (BSA) at all evaluated pHs. FPH foaming capacity was not affected by pH, however, foam stability was equal or better than that of BSA, especially at pH 4.0 (P ≤ 0.05). These results suggest the possibility of producing FPH with similar or better functional properties than those of functional ingredients, such as SCA and BSA. Furthermore, the data presented support our hypothesis that the high proteolytic activity in Pacific whiting could be used as an advantage in fish protein hydrolysate production or as a processing aid where protein hydrolysis is required.     

Effect of extra virgin olive oil on glycaemia in healthy young subjects

In this approach we studied the glycaemia levels in 20 healthy young volunteers (26 ± 2 years), before and after a 30‐day intake of 50 mL of extra virgin olive oil (EVOO). We selected an oil rich in phenolic compounds (523 mg/L) with a high content of secoiridoidic derivatives (over 94.5%). The findings from our study reveal a significant decrease of glycaemia from 89.6 ± 6.8 to 82.7 ± 10.3 mg/dL (p<0.05), related to a long term daily intake of the study EVOO, as the only added fat. A significant increment of the HDL cholesterol, from 68.7 ± 11.5 to 75.2 ± 4.9 mg/dL, was also highlighted. Total cholesterol, LDL, VLDL, triglycerides, and blood pressure did not show significant variation after the 30‐day consumption of this EVOO. So far, few articles have described the influence of EVOO consumption, on plasma glucose levels in humans. This effect is observed in a group of healthy young humans. Moreover, we confirm that the level of free hydroxytyrosol (OH‐Tyr) in plasma increased up to fourfold (p<0.05) after the 30‐day intake of this EVOO. In addition, the excretion in urine of the main metabolite of OH‐Tyr, homovanillic acid (HVA), significantly increased.     

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.     

Assessing Rubus honey value: Pollen and phenolic compounds content and antibacterial capacity

Twenty-three honey samples from Galicia (Northwest Spain) were analysed to determine their botanical origin, phenolic compounds and antibacterial activity. In all samples Rubus pollen was predominant, followed by that of Castanea sativa. Other important pollens found belong to Cytisus type, Trifolium repens, Echium, Eucalyptus globulus, Erica umbellata, Erica cinerea, Campanula type and Frangula alnus.Eight phenolic compounds (caffeic, p-coumaric and ellagic acids, pinocembrin, chrysin, galangin, tectochrysin and kaempferol) were determined by solid-phase extraction (SPE) followed by HPLC/DAD analysis. p-Coumaric and ellagic acids were the main constituents of the phenolic fraction (ca. 5.5 mg/kg each, mean value), followed by the pair chrysin plus galangin (ca. 1.2 mg/kg, mean value) and pinocembrin (ca. 1.0 mg/kg, mean value). Antibacterial activity was checked against five Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Enterococcus faecalis and Bacillus cereus) and four Gram-negative bacteria (Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium). B. cereus and P. mirabilis were the most sensitive microorganisms. This is the first study concerning the phenolic compounds and antibacterial activity of Rubus honey, which proved to be a good source of phenolic compounds and antimicrobial agents with potential health benefits.     

Deep‐fat frying under moderate vacuum of potato cylinders

This study evaluates parameters relating to the mass transfer during the frying of potato cylinders at different temperatures (100, 120 and 140 °C) and moderate vacuum (around 25 kPa). In all cases, there is a linear relation between water loss and fat uptake. The parameters relating to the textural and structural modifications show less marked changes in vacuum fried products compared to those fried under atmospheric pressure. The maximum penetration force reaches 30%–40% of the initial hardness in vacuum frying and 10% for atmospheric pressure frying; starch gelatinization and pectin methylesterase enzyme activity reduce more quickly under atmospheric pressure, although after 240 s both values are negligible. The scanning electron microscopy images verify that the surface of potato cylinders fried under vacuum or atmospheric pressure are completely different as a result of the steam being released at different temperatures.     

Health-promoting effects in the gut and influence on lipid metabolism of Himanthalia elongata and Gigartina pistillata in hypercholesterolaemic Wistar rats

The intake of Himanthalia elongata and Gigartina pistillata from the Spanish Atlantic coasts was evaluated in Wistar rats. Both seaweed diets showed higher (p < 0.001) faecal excretion. Colonic fermentation increased (p < 0.001) total short-chain fatty acids (SCFAs) in Himanthalia-fed rats due to the higher (p < 0.001) levels of acetic, propionic and butyric acids. The intake of Gigartina increased (p < 0.001) propionic acid and decreased (p < 0.001) butyric acid. The apparent absorption and true retention of calcium and magnesium enhanced (p < 0.05) with Himanthalia diet, while Gigartina produced no significant effect. The serum concentration of HDL-C increased (p < 0.01), triglycerides (TGL) decreased (p < 0.001) and bile acids diminished (p < 0.001) in faeces of Himanthalia-fed rats. The Gigartina diet produced a decrease (p < 0.001) in TGL, total cholesterol (p < 0.01) and LDL-C (p < 0.05) in serum and reduced TGL in liver (p < 0.001). Thus, both seaweeds improved the lipid profile, and Himanthalia increased SCFA production and the absorption and retention of Ca and Mg as a result of the gut fermentation.