Thermodynamics of Chaplygin gas

We clarify thermodynamics of the Chaplygin gas by introducing the integrability condition. All thermal quantities are derived as functions of either volume or temperature. Importantly, we find a new general equation of state, describing the Chaplygin gas completely. We confirm that the Chaplygin gas could show a unified picture of dark matter and energy which cools down through the universe expansion without any critical point (phase transition).Comment: 5 pages, 4 figures, version "Accepted for publication in Astrophysics & Space Science

Power spectrum in the Chaplygin gas model: tachyonic, fluid and scalar field representations

The Chaplygin gas model, characterized by an equation of state of the type $p = - \frac{A}{\rho}$ emerges naturally from the Nambu-Goto action of string theory. This fluid representation can be recast under the form of a tachyonic field given by a Born-Infeld type Lagrangian. At the same time, the Chaplygin gas equation of state can be obtained from a self-interacting scalar field. We show that, from the point of view of the supernova type Ia data, the three representations (fluid, tachyonic, scalar field) lead to the same results. However, concerning the matter power spectra, while the fluid and tachyonic descriptions lead to exactly the same results, the self-interacting scalar field representation implies different statistical estimations for the parameters. In particular, the estimation for the dark matter density parameter in the fluid representation favors a universe dominated almost completely by dark matter, while in the self-interacting scalar field representation the prediction is very closed to that obtained in the $\Lambda$CDM model.Comment: Latex file, 10 pages, 18 figures in EPS forma

Spray-drying microencapsulation of synergistic antioxidant mushroom extracts and their use as functional food ingredients

In this work, hydroalcoholic extracts of two mushrooms species, Suillus luteus (L.: Fries) (Sl) and Coprinopsis atramentaria (Bull.) (Ca), were studied for their synergistic antioxidant effect and their viability as functional food ingredients tested by incorporation into a food matrix (cottage cheese). In a first step, the individual extracts and a combination of both, showing synergistic effects (Sl:Ca, 1:1), were microencapsulated by spray-drying using maltodextrin as the encapsulating material. The incorporation of free extracts resulted in products with a higher initial antioxidant activity (t0) but declining after 7 days (t7), which was associated with their degradation. However, the cottage cheese enriched with the microencapsulated extracts, that have revealed a lower activity at the initial time, showed an increase at t7. This improvement can be explained by an effective protection provided by the microspheres together with a sustained release. Analyses performed on the studied cottage cheese samples showed the maintenance of the nutritional properties and no colour modifications were noticed.Financial support was provided by FCT/MEC and FEDER under Programme PT2020 (LSRE: Project UID/EQU/50020/2013and CIMO: PEst-OE/AGR/UI0690/2014) and QREN, ON2 and FEDER (Project NORTE-07-0162-FEDER-000050 and NORTE-07-0124-FEDER-000014). G. Ruphuy thanks Universidad de Costa Rica (UCR) and Ministerio de Ciencia, Tecnología y Telecomunicaciones de Costa Rica (MICITT) for her scholarship and L. Barros FCT for her contract (Compromisso para a Ciência 2008). A special thanks to Cargill for having provided us with the maltodextrin sample used in this work (reference C*Dry MD 01915)

Primate innate immune responses to bacterial and viral pathogens reveals an evolutionary trade-off between strength and specificity

Despite their close genetic relatedness, apes and African and Asian monkeys (AAMs) differ in their susceptibility to severe bacterial and viral infections that are important causes of human disease. Such differences between humans and other primates are thought to be a result, at least in part, of interspecies differences in immune response to infection. However, because of the lack of comparative functional data across species, it remains unclear in what ways the immune systems of humans and other primates differ. Here, we report the whole-genome transcriptomic responses of ape species (human and chimpanzee) and AAMs (rhesus macaque and baboon) to bacterial and viral stimulation. We find stark differences in the responsiveness of these groups, with apes mounting a markedly stronger early transcriptional response to both viral and bacterial stimulation, altering the transcription of ~40% more genes than AAMs. Additionally, we find that genes involved in the regulation of inflammatory and interferon responses show the most divergent early transcriptional responses across primates and that this divergence is attenuated over time. Finally, we find that relative to AAMs, apes engage a much less specific immune response to different classes of pathogens during the early hours of infection, up-regulating genes typical of anti-viral and anti-bacterial responses regardless of the nature of the stimulus. Overall, these findings suggest apes exhibit increased sensitivity to bacterial and viral immune stimulation, activating a broader array of defense molecules that may be beneficial for early pathogen killing at the potential cost of increased energy expenditure and tissue damage. Copyrigh

Simulación de gases en cámaras de almacenamiento de fruta

Simulation of Gases in Fruit Cold Storage Chambers: Nowadays there is an increasing use of low Oxygen (LO) and ultra low Oxygen (ULO) atmospheres for long term cold storage of fruits. Some physiological disorders associated with these postharvest technologies point to the presence of small spatial gradients in gas concentration as the major cause. However, it is extremely difficult to perform experimental tests measuring spatial gas gradients with sufficient resolution. In this study a spatiotemporal gas simulation software has been developed as a decision tool with the aim to evaluate various stowage and fruit conditions, as well as containers design