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

Fatty acis profile in Serra da Estrela cheese: an overview

Milk and dairy products are of major importance in the human diet, since they are an excellent source of well-balanced nutrients which are consumed in large amounts and are easy to manufacture. Most cheeses present in the market are made from cow's milk, with ewe’s and goat’s cheeses being considered delicacies derived from the unavailability of goat's and ewe’s milk in certain periods of the year, proleading to a final product with high prices that consumers tend to value given the quality of the final products. Serra Estrela (SE) cheese, a traditional variety manufactured in the center region of Portugal, is part of the national ancient cultural heritage. Made from raw sheep milk it is assumed as an iconic gourmet cheese, when compared with other Portuguese cheeses. In the present work, the evolution of the lipid fraction, namely unsaturated fatty acids such as monounsaturated and polyunsaturated (omega 3 fatty acids and omega 6 fatty acids), was evaluated for a period of 9 months. Chemically it was possible to verify differences in terms of the fatty acid profile between the analysed cheese samples. SE cheese was characterized by a relatively high content of monounsaturated fatty acids (MUFA) and the evaluation of the lipid profile of SE cheese allowed possible future work in determining bioactive lipid compounds with possible health promoting functions.info:eu-repo/semantics/publishedVersio

Towards predicting liquid fuel physicochemical properties using molecular dynamics guided machine learning models

Accurate determination of fuel properties of complex mixtures over a wide range of pressure and temperature conditions is essential to utilizing alternative fuels. The present work aims to construct cheap-to-compute machine learning (ML) models to act as closure equations for predicting the physical properties of alternative fuels. Those models can be trained using the database from MD simulations and/or experimental measurements in a data-fusion-fidelity approach. Here, Gaussian Process (GP) and probabilistic generative models are adopted. GP is a popular non-parametric Bayesian approach to build surrogate models mainly due to its capacity to handle the aleatory and epistemic uncertainties. Generative models have shown the ability of deep neural networks employed with the same intent. In this work, ML analysis is focused on two particular properties, the fuel density and diffusion, but it can also be extended to other physicochemical properties. This study explores the versatility of the ML models to handle multi-fidelity data. The results show that ML models can predict accurately the fuel properties of a wide range of pressure and temperature conditions.The research leading to these results had received funding from the Brazilian National Agency of Petroleum, Natural Gas and Biofuels (ANP) through Programa de Recursos Humanos (PRH) under the PRH 8 - Mechanical Engineering for the Efficient Use of Biofuels, grant agreement numbers F0A5.EDDE.B5C0.3BCB and 2B61.4F5C.A83B.A713.Peer ReviewedPostprint (published version

Are biological species and higher-ranking categories real? Fish folk taxonomy on Brazil’s Atlantic Forest coast and in the Amazon

Analysis of Brazilian fishers' classifications of 24 marine (Atlantic coast) and 24 freshwater (Amazon) fish species reveals that fishers from the Atlantic coast identify fish mainly through generic names (primary lexemes), while riverine Amazonian fishers typically identify them through binomials. The similarity of Amazonian fish species seems to contribute to the detailed folk taxonomy used by riverine fishers. High-ranking groups called "relatives" or "cousins" are sorted by fishers in terms of similarities of habitat, diet, and morphology and, secondarily, behavior. The general correspondence between the folk and scientific taxonomies reinforces the reality of both the supracategories used by these fishers and the biological groups as discontinuities in nature. Given the urgency of biological inventories and the lack of knowledge of high-biodiversity environments such as the Atlantic Forest and the Amazon, these results suggest that fisher knowledge and experience could contribute to scientific research.49229130

Mutual use of trail-following chemical cues by a termite host and its inquiline

Termite nests are often secondarily inhabited by other termite species ( = inquilines) that cohabit with the host. To understand this association, we studied the trail-following behaviour in two Neotropical species, Constrictotermes cyphergaster (Termitidae: Nasutitermitinae) and its obligatory inquiline, Inquilinitermes microcerus (Termitidae: Termitinae). Using behavioural experiments and chemical analyses, we determined that the trail-following pheromone of C. cyphergaster is made of neocembrene and (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol. Although no specific compound was identified in I. microcerus, workers were able to follow the above compounds in behavioural bioassays. Interestingly, in choice tests, C. cyphergaster prefers conspecific over heterospecific trails while I. microcerus shows the converse behaviour. In no-choice tests with whole body extracts, C. cyphergaster showed no preference for, while I. microcerus clearly avoided heterospecific trails. This seems to agree with the hypothesis that trail-following pheromones may shape the cohabitation of C. cyphergaster and I. microcerus and reinforce the idea that their cohabitation is based on conflict-avoiding strategies

Pathogenic Rickettsia in ticks of spur-thighed tortoise (Testudo Graeca) sold in a Qatar live animal market

The dissemination of vector arthropods harbouring zoonotic pathogens through the uncontrolled transboundary trade of exotic and pet animals poses an important threat to Public Health. In the present report, we describe the introduction of pathogenic Rickettsia africae and R. aeschlimanni in ticks removed from imported tortoises in Qatar. A total of 21 ticks were collected from pet spur‐thighed tortoises (Testudo graeca) from Doha, May 2018, and studied for species identification and characterization of Rickettsia spp. Morphological and molecular analysis of ticks allowed their identification as Hyalomma aegyptium. Molecular analysis of partial ompA and gltA genes showed that Rickettsia sequences found on these ticks clustered with sequences classified as R. aeschilimanii and R. africae. Since pre‐adult stages of H. aegyptium also feed on humans, this tick species may play a role in the transmission of R. aeschilimanii and R. africae. We alert for the introduction of non‐native pets as vehicles for tick importation, known vectors for animal and human pathogenic agents. Importation of exotic species into non‐autochthonous countries deserves strict control to enforce robust surveillance and mitigate potential exotic diseases epidemics.P. Barradas (SFRH/BD/116449/2016) acknowledges the Portuguese Foundation for Science and Technology (FCT) for financial support. IPATIMUP integrates the i3S Research Unit, which is partially supported by FEDER funds through the Operational Programme for Competitiveness Factors‐COMPETE and National Funds through the FCT, under the project number Pest‐C/SAU/LA0003/2013. This paper was published under the framework of the European Social Fund, Human Resources Development Operational Programme 2007–2013 (POSDRU/159/1.5/S/136893).info:eu-repo/semantics/publishedVersio

Meninas.comp: computación para niñas en escuelas primarias de Brasil

The Computing field has a gender diversity gap, with female participation much lower when compared to men. In this context, several activities have been developed to include more women in the field of Computing, and the Meninas.comp project has been working to introduce Computing to girls in elementary schools in Brasilia, the capital of Brazil. This article has two objectives: i) to present the activities of the Meninas.comp project for girls in elementary schools; ii) to present a mapping of the literature on computational activities with a focus on girls in elementary schools in Brazil. The systematic literature mapping found publications reporting a large variety of activities, such as unplugged computing, game development, card games, programming classes, competitions, lectures, and workshops. From the Meninas.comp project, this article highlights a smart garden developed by female elementary school students.El campo de la informática tiene una brecha de diversidad de género, con una participación femenina mucho menor en comparación con los hombres. Al respecto, se han desarrollado varias actividades para incluir a más mujeres en el campo de la Computación. El proyecto Meninas.comp ha trabajado en Informática para niñas de escuelas primarias en Brasilia, capital de Brasil. En este contexto, este artículo tiene dos objetivos: i) presentar las actividades del proyecto Meninas.comp en escuelas primarias de niñas; ii) presentar un mapeo de la literatura sobre actividades computacionales con enfoque en niñas de escuelas primarias en Brasil. El mapeo sistemático de literatura encontró publicaciones que informan una gran variedad de actividades, como computación desconectada, desarrollo de juegos, juegos de cartas, clases de programación, concursos, conferencias y talleres. Del proyecto Meninas. comp, este artículo destaca un jardín inteligente desarrollado por alumnas de primaria

Testing dark energy beyond the cosmological constant barrier

Although well motivated from theoretical arguments, the cosmological constant \emph{barrier}, i.e., the imposition that the equation-of-state parameter of dark energy ($\omega_x \equiv p_x/\rho_x$) is $\geq -1$, seems to introduce bias in the parameter determination from statistical analyses of observational data. In this regard, \emph{phantom} dark energy or \emph{superquintessence} has been proposed in which the usual imposition $\omega \geq -1$ is relaxed. Here, we study possible observational limits to the \emph{phantom} behavior of the dark energy from recent distance estimates of galaxy clusters obtained from interferometric measurements of the Sunyaev-Zel'dovich effect/X-ray observations, Type Ia supernova data and CMB measurements. We find that there is much \emph{observationally} acceptable parameter space beyond the $\Lambda$ \emph{barrier}, thus opening the possibility of existence of more exotic forms of energy in the Universe.Comment: 5 pages, 5 figures, to appear in Phys. Rev.