de Broglie-Proca and Bopp-Podolsky massive photon gases in cosmology

We investigate the influence of massive photons on the evolution of the expanding universe. Two particular models for generalized electrodynamics are considered, namely de Broglie-Proca and Bopp-Podolsky electrodynamics. We obtain the equation of state (EOS) $P=P(\varepsilon)$ for each case using dispersion relations derived from both theories. The EOS are inputted into the Friedmann equations of a homogeneous and isotropic space-time to determine the cosmic scale factor $a(t)$. It is shown that the photon non-null mass does not significantly alter the result $a\propto t^{1/2}$ valid for a massless photon gas; this is true either in de Broglie-Proca's case (where the photon mass $m$ is extremely small) or in Bopp-Podolsky theory (for which $m$ is extremely large).Comment: 8 pages, 2 figures; v2 matches the published versio

Percepções leigas sobre as desigualdades na saúde e no ambiente e suas associações com a saúde mental

Health inequalities are very well documented in epidemiological research: rich people live longer and have less diseases than poor persons. Recently, a growing amount of evidence from environmental sciences confirms that poor people are also more exposed to pollution and other environmental threats. However, research in the social sciences has shown a wide unawareness of health inequalities. In this paper, based on data collected in Portugal, we will analyse the consciousness of both health and environmental injustices and test one hypothesis for this social blindness. The results show, even more clearly than before, that public opinion tends to see rich and poor people equally susceptible to health and environmental events. Besides, those who have this equal view of the world present lower levels of depression and anxiety. Following cognitive adaptation theory, this “belief in an equal world” can be interpreted as a protective positive illusion about social justice, particularly relevant in one of the most unequal countries in Europe.info:eu-repo/semantics/publishedVersio

Current-driven and field-driven domain walls at nonzero temperature

We present a model for the dynamics of current- and field-driven domain-wall lines at nonzero temperature. We compute thermally-averaged drift velocities from the Fokker-Planck equation that describes the nonzero-temperature dynamics of the domain wall. As special limits of this general description, we describe rigid domain walls as well as vortex domain walls. In these limits, we determine also depinning times of the domain wall from an extrinsic pinning potential. We compare our theory with previous theoretical and experimental work

Emergent sources of prebiotics: seaweeds and microalgae

In recent years, scientists have become aware that human microbiota, in general, and gut microbiota, in particular, play a major role in human health and diseases, such as obesity and diabetes, among others. A large number of evidence has come to light regarding the beneficial effects, either for the host or the gut microbiota, of some foods and food ingredients or biochemical compounds. Among these, the most promising seem to be polysaccharides (PS) or their derivatives, and they include the dietary fibers. Some of these PS can be found in seaweeds and microalgae, some being soluble fibers, such as alginates, fucoidans, carrageenans and exopolysaccharides, that are not fermented, at least not completely, by colonic microbiota. This review gives an overview of the importance of the dietary fibers, as well as the benefits of prebiotics, to human health. The potential of the PS from marine macro- and microalgae to act as prebiotics is discussed, and the different techniques to obtain oligosaccharides from PS are presented. The mechanisms of the benefits of fiber, in general, and the types and benefits of algal fibers in human health are highlighted. The findings of some recent studies that present the potential effects of prebiotics on animal models of algal biomass and their extracts, as well as oligo- and polysaccharides, are presented. In the future, the possibility of using prebiotics to modulate the microbiome, and, consequently, prevent certain human diseases is foreseen.info:eu-repo/semantics/publishedVersio

Edible coatings with polysaccharides and bioactive compounds from exhausted olive oil pomace to extend the shelf life of strawberry

Introduction: Exhausted or delipidified olive oil pomace (EOP) is a by-product generated from the olive pomace after air drying and hexane extraction of residual oil [1]. This by-product is rich in phenolic compounds, such as hydroxytyrosol, tyrosol and catechol, with associated properties: antioxidant, antimicrobial, anti- inflammatory, anti-diabetic, anti-carcinogenic and anti-HIV [1, 2]. Coatings and films are materials used for example to increase the shelf life of perishable fruits and vegetables. They can be made of polysaccharides, lipids and proteins from natural sources. It is essential to include bioactive compounds in the formulation to achieve bioactive properties, such as antimicrobial and antioxidant activities [3]. In this work a coating was performed using alginate and an extract rich in phenolics from EOP to increase the shelf life of strawberry (Fragaria ananassa). Objectives: To develop an edible coating using alginate and an extract rich in phenolics from EOP. To apply the coating to a perishable fruit, such as strawberry. To determine the moisture loss of the coated strawberry. To observe the natural decay of strawberry. To determine the growing curves of mesophilic aerobic bacteria, psychrophilic bacteria, Enterobacteriaceae, yeasts and molds in the coated strawberry. Conclusions: The formulation 2 % alginate + 5 % EOP extract can be successfully used as an edible coating. The application of the coating on strawberry are effective to prevent moisture loss, maintaining the quality of the fruits. It prevents the proliferation of several bacteria, such as psychrophilic bacteria, mesophilic aerobic bacteria, yeasts and molds.info:eu-repo/semantics/publishedVersio

Antioxidant activity and total phenolic content of different extracts of delipidified olive oil pomace

Introduction: The use of by-products as a source of bioactive compounds with economic added value is one of the objectives of the circular economy. Olive oil industry is a source of olive pomace, as a by-product. The olive pomace used in the present study was the exhausted (delipidified) olive pomace, which is the by-product generated after drying and subsequent hexane extraction of residual oil from the olive pomace. This exhausted olive oil pomace may contain remaining bioactive compounds, such as phenolic compounds, which can be of interest not only for the food industry, but also for the pharmaceutical and cosmetic industries. Objectives: Various types of green methodologies, such as solvent extraction (water and hydroalcoholic), ultrasound-assisted extraction, ultra-turrax-assisted extraction and enzyme-assisted extraction (cellulase; viscoenzyme) were used to obtain extracts rich in bioactive compounds from the exhausted olive oil pomace. The bioactivity of these extracts was evaluated through the antioxidant activity. Conclusions: Among all methodologies used the extractions with enzymes produced the best yields of extraction and the conventional extraction with water at 50 °C produced the best results for the total phenolic content and antioxidant activity: ABTS, DPPH and ORAC.info:eu-repo/semantics/publishedVersio