Metabolomic analysis by UAE-GC MS and antioxidant activity of <i>Salvia hispanica </i>(L.) seeds grown under different irrigation regimes

Chia (Salvia hispanica L.) is an emerging crop with a high content of α-linolenic acid and metabolites of industrial and pharmaceutical interest but information on metabolome variations in response to agricultural management is scarce. We investigated the yield and metabolic profile of the seeds of two chia populations, one commercial black (B) and one long-day flowering genotype (G8), in response to two irrigation levels: replacement of 100% ET⁠0 (I) or rainfed (NI). Seed yield was higher in irrigated plots in G8 only (0.255kgm⁠−2 for I vs 0.184kgm⁠−2 for NI) while it was very low regardless of irrigation in B due to late flowering. Ultrasound assisted extraction (UAE) of seeds followed by gas chromatography-mass spectrometry (GC/MS) analysis showed differences in fatty acids and the major classes of organic compounds due to both genotype and irrigation, especially in the non-polar phase where irrigated samples showed a higher content of α-linolenic and other fatty acids and a lower oleic/linoleic ratio (47.4 in NI vs. 39.6 in I). The antioxidant activity, expressed as trolox equivalent antioxidant capacity (TEAC), ranged from 1.317±0.027 to 2.174±0.010mmol TEAC/g of defatted chia seed after 2 and 40min respectively, and was negatively affected by irrigation. The total polyphenolic content (TPC) measured with the Folin-Ciocalteu method, also decreased with irrigation. According to our results irrigation can affect chia yield, metabolome and antioxidant behavior but some of the effects are genotype-dependent

Metabolomics driven analysis by UAEGC-MS and antioxidant activity of Chia (<i>Salvia hispanica </i>L.) commercial and mutant seeds

Chia is a food plant producing seeds which have seen increasing interest owing to their health benefits. This work is the first report on the metabolite profile, total polyphenols and antioxidant activity of chia seeds, determined by ultrasound-assisted extraction, coupled with gas chromatography-mass spectrometry (UAE GC-MS). Different chia sources were compared: two commercial (black and white) and three early flowering (G3, G8 and G17) mutant genotypes. Organic extracts were mainly composed of mono- and polyunsaturated fatty acids with alpha-linolenic being the most abundant. Polar extracts contained sucrose, methylgalactoside and glucose as main sugars. Antioxidant activity and total polyphenolic content were correlated. Chemical composition and yield potential of early flowering genotypes were different from commercial chia, and while white chia showed the highest content of omega-3 fatty acids, the high content of nutraceuticals in G17 and G8 suggests them as a potential source of raw materials for the food/feed industry

Colouring of Voloshin for ATS(v)

A mixed hypergraph is a triple H=(S,C,D), where S is the vertex set and each of C,D is a family of not-empty subsets of S, the C-edges and D-edges respectively. A strict k-colouring of H is a surjection f  from the vertex set into a set of colours {1, 2, . . . , k} so that each C-edge contains at least two distinct vertices x, y such that f(x) = f(y) and each D-edge contains at least two vertices x, y such that f(x)=f(y). For each k ∈ {1, 2, . . . , |S|}, let r_k be the number of partitions of the vertex set into k not-empty parts (the colour classes) such that the colouring constraint is satisfied on each C-edge and D-edge. The vector R(H ) = (r_1 , . . . , r_k ) is called the chromatic spectrum of H. These concepts were introduced by V. Voloshin in 1993 [6].In this paper we examine colourings of mixed hypergraphs in the case that H is an ATS(v)

El oficio debe unirse a la academia

¿Son excluyentes la enseñanza del periodismo y oficio mismo? ¿O será qué las facultades donde se estudian las ciencias de la comunicación no nacieron con la idea desformar periodistas profesionales? Entonces, ¿quieren las facultades que enseñan ciencias de la comunicación formar periodistas profesionales? ¿Debemos hablar de ciencias de la comunicación o de ciencias de la información? Se me ocurre que una universidad de periodismo, al estilo de la de Columbia en los Estados Unidos, nos ahorraría lustros de debate. Pero también sé que mientras estas preguntas sigan sin respuesta y la enseñanza de las “cosas del oficio” esté reducida en las facultades a un mero trámite formal, destinado acaso a que el estudiante no opte por las academias privadas que ofrecen una práctica periodística más activa, más intensa y más atractiva aunque sin el soporte cultural de cualquiera de nuestras universidades públicas, oficio y academia seguirán, como hasta hoy, caminos separados con escasos y errantes puntos de contacto.Facultad de Periodismo y Comunicación Socia

Leading points concepts in turbulent premixed combustion modeling

The propagation of premixed flames in turbulent flows is a problem of wide physical and technological interest, with a significant literature on their propagation speed and front topology. While certain scalings and parametric dependencies are well understood, a variety of problems remain. One major challenge, and focus of this thesis, is to model the influence of fuel/oxidizer composition on turbulent burning rates. Classical explanations for augmentation of turbulent burning rates by turbulent velocity fluctuations rely on global arguments - i.e., the turbulent burning velocity increase is directly proportional to the increase in flame surface area and mean local burning rate along the flame. However, the development of such global approaches is complicated by the abundance of phenomena influencing the propagation of turbulent premixed flames. Emphasizing key governing processes and cutting-off interesting but marginal phenomena appears to be necessary to make further progress in understanding the subject. An alternative approach to understand turbulent augmentation of burning rates is based upon so-called "leading points", which are intrinsically local properties of the turbulent flame. Leading points concepts suggest that the key physical mechanism controlling turbulent burning velocities of premixed flames is the velocity of the points on the flame that propagate farthest out into the reactants. It is postulated that modifications in the overall turbulent combustion speed depend solely on modifications of the burning rate at the leading points since an increase (decrease) in the average propagation speed of these points causes more (less) flame area to be produced behind them. In this framework, modeling of turbulent burning rates can be thought as consisting of two sub-problems: the modeling of (1) burning rates at the leading points and of (2) the dynamics/statistics of the leading points in the turbulent flame. The main objective of this thesis is to critically address both aspects, providing validation and development of the physical description put forward by leading point concepts. To address the first sub-problem, a comparison between numerical simulations of one-dimensional laminar flames in different geometrical configurations and statistics from a database of direct numerical simulations (DNS) is detailed. In this thesis, it is shown that the leading portions of the turbulent flame front display a structure that on average can be reproduced reasonably well by results obtained from model geometries with the same curvature. However, the comparison between model laminar flame computations and highly curved flamelets is complicated by the presence of negative (i.e., compressive) strain rates, due to gas expansion. For the highest turbulent intensity investigated, local consumption speeds, curvatures, strain rates and flame thicknesses approach the maximum values obtained by the laminar model geometries, while other cases display substantially lower values. To address the second sub-problem, the dynamics of flame propagation in simplified flow geometries is studied theoretically. Utilizing results for Hamilton-Jacobi equations from the Aubry-Mather theory, it is shown how the overall flame front progation under certain conditions is controlled only by discrete points on the flame. Based on these results, definitions of leading points are proposed and their dynamics is studied. These results validate some basic ideas from leading points arguments, but also modify them appreciably. For the simple case of a front propagating in a one-dimensional shear flow, these results clearly show that the front displacement speed is controlled by velocity field characteristics at discrete points on the flame only when the amplitude of the shear flow is sufficiently large and does not vary too rapidly in time. However, these points do not generally lie on the farthest forward point of the front. On the contrary, for sufficiently weak or unsteady flow perturbations, the front displacement speed is not controlled by discrete points, but rather by the entire spatial distribution of the velocity field. For these conditions, the leading points do not have any dynamical significance in controlling the front displacement speed. Finally, these results clearly show that the effects of flame curvature sensitivity in modifying the front displacement speed can be successfully interpreted in term of leading point concepts.Ph.D

An edge colouring of multigraphs

We consider a strict k-colouring of a multigraph G as a surjection f from the vertex set of G into a set of colours {1,2,…,k} such that, for every non-pendant vertex χ of G, there exist at least two edges incident to χ and coloured by the same colour. The maximum number of colours in a strict edge colouring of G is called the upper chromatic index of G and is denoted by χ(G). In this paper we prove some results about it