1,883 research outputs found

    Interactive effects of solar UV radiation and ammonium on the biomass andnutritional compound production in tank cultivated Hydropuntia corne (Rhodophyta)

    Get PDF
    Figueroa et al. (2016) Acta Aquaculture 16, 331-332Introduction Hydropuntia cornea is a red alga species cultivated in tanks under nitrogen enrichment with high biomass production and content of high value bioactive compounds (Figueroa et al., 2012; Robledo et al, 2014). In this study, the combined effects (2 × 2 factorial design) of solar radiation (in door (I), green house cutting off the UV radiation and out-door (O) with UV radiation) and nitrogen (ammonium) under high (HN) and low (LN) levels on biomass production (g DW m-2 d-1), biofiltration as Nitrogen uptake efficiency (NUE, %) and Nitrogen uptake rate (NUR, mmol N m-2 h-1), photosynthetic activity as maximal electron transport rate (ETRmax), starch content and antioxidant activity were analyzed in H.cornea grown in tanks for 35 days in the above mentioned conditions. Material and methods The red seaweed Hydropuntia cornea was cultivated in cylindrical tanks of 90 L (0.17 m2 superficial area) with open flow-through N and P-enrichment (5 NH4Cl: 1 KHPO4, in a concentration ranges between 50 - 250 µM). Seaweed density assayed in tanks was 9 g FW L-1. Turnover rates were 64 and 6.4 vol d-1 in high and low flow rate, respectively. Photosynthetic activity was measured by using in vivo chlorophyll a fluorescence associated to photosystem II i.e. Electron transport rate (ETR) expressed as μmol electrons m-2 s-1. Starch (%) was determined according to anthrone method (Brooks et al. 1986) and antioxidant activity was evaluated following ABTS method (Ree et al., 1999) and expressed as Trolox equivalent (μM TEAC g-1 DW). Results Maximal photosynthetic production (ETRmax) increased throughout the culture time. (Fig. 1.A). After 35 d culture, ETRmax was higher under HN than that under LN both under in door and out door conditions (Fig.1A). However, biomass production expressed as g DW m-2 d-1 decreased throughout the experimental time (Fig 1.B). After 35d culture the highest biomass production was reached under HN-O and the lowest under LN-O although the differences were not so high (Fig.1B). The maximal efficiency of N assimilation (NUE %) was greater under LN (98%) than that under HN treatment (72%). NUE decreased throughout the time although after 35 d a clear increase was observed (Table 1). In contrast, the maximal nitrogen uptake rate (NUR) was higher under HN (45.5 mmol N m-2 h-1) than that under LN (25.8 mmol N m-2 h-1). The highest values of both NUE and NUR were obtained under solar radiation (outdoor treatments). Starch ranged from 25.1% (LN-I, 21 d) to 49.6 % (LN-O, 28 d) whereas the highest antioxidant activity was reached under LN-O after 21 d culture (68.5 μM TEAC g-1 DW). After 35d the highest level was again under LN-O (65.2 μM TEAC g-1 DW) followed by HN-O treatment (57.3 μM TEAC g-1 DW).Discussion and conclusions Ammonium supply, simulating fishpond effluents, and full solar irradiation (presence of UV radiation) have a positive effect on photosynthetic rate as ETRmax. The decrease in biomass production in spite of the increase of photosynthetic activity and nitrogen uptake rate is explained because the algae through the time could inverse more energy for the accumulation of metabolites (starch and antioxidant compounds) that that for growth. In any case the highest accumulation of starch and antioxidant activity were observed in the treatments associated to the greatest stress conditions i.e LN and outdoor culture due to UVR can negatively affect biological processes related to growth. As expected, under HN supply NUE was lower than that under LN but NUR was the reverse. H. cornea grown in simulated fishpond effluents displays a high biofiltration rate of inorganic N and accumulates commercially N compounds, as the photoprotector-antioxidant substances, mycosporine-like aminoacids (Figueroa et al., 2012) and C-compounds for nutritional uses or bioethanol production. In this study, the antioxidant activity was much higher than that reported in other seaweeds (Matanjun et al., 2008). H. cornea can be cultured and used to remove nutrient-rich fishpond effluents from aquaculture industries and besides, this biomass provides compounds of high added value for the biotechnology industry. References Brooks, J.R., Griffin, V.K., Kattan, M.W. 1986.A modified method for total carbohydrate analysisof glucose syrups, maltodextrins and other starch hydrolysis products. Cereal Chem 63:465-466. Figueroa, F. L., Korbee, N., Abdala, R., Jerez, C. G., López-de la Torre, M., Güenaga, L., Gómez-Pinchetti, J. L. 2012. Biofiltration of fishpond effluents and accumulation of N-compounds (phycobiliproteins and mycosporine-like amino acids) versus C-compounds (polysaccharides) in Hydropuntia cornea (Rhodophyta). Marine Pollution Bulletin, 64(2), 310-318. Matanjun, P., Mohamed, S., Mustapha, N.M., Ming, C.H. 2008. Antioxidant activities and phenolics content of eight species of seaweeds from north Borneo. J Appl Phycol 20:367–373. Re, R., Pellegrini, N., Proteggente, A., Pannala, A.,Yang,M., Rice-Evans, C. 1999. Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radic Biol Med 26:1231–1237. Robledo, D., Navarro‐Angulo, L., Valdes Lozano, D., Freile‐Pelegrín, Y. 2014. Nutrient removal efficiency of Hydropuntia cornea in an integrated closed recirculation system with pink shrimp Farfantepenaeus brasiliensis. Aquaculture Research, 45(10), 1648-1658Universidad de Málaga.Campus de Excelencia Internacional Andalucia Tech

    Crisis and Welfare Society in Spain

    Get PDF
    Some arguments are briefly presented about the negative consequences of the deep global economic and financial crisis of 2008 on the economic activity and the social situation in Spain. Reformulation, sustainability and financial viability of social welfare in Spain require a new management through resource efficiency, increasing market presence and initiative of stakeholders as a whole. In this sense, the main credible argument of the welfare social in Spain depends on a new perspective on socialization and generosity of social protection system. Specifically, the solution to the crisis must come through economic growth, increased productivity, employment and competitiveness and not by the way of increasing levels of social protection

    La fotografía en el noreste de México

    Get PDF
    Este artículo expone el camino que permitió la llegada de la fotografía al noreste de México, de la cámara oscura al daguerrotipo; de la primer fotografía tomada en México en 1839 apenas desembarcó el daguerrotipo en el puerto de Veracruz, a Eduard Wilder primer fotógrafo que llegó a Monterrey en 1842; los fotógrafos que vinieron con la invasión norteamericana de 1846 a 1848, primero a Matamoros, después a Monterrey y Saltillo; otros retratistas errantes tocarían el noreste como Cayetano Yzquierdo que se pensó era el primer fotógrafo norteño, pero Ricardo Elizondo descubre que arribó de Cuba, quedando Sabás Treviño como el primer fotógrafo local con las reservas de descubrir después que su apellido tan común en la región tenga otro origen; Nicolás Mauro Rendón, Desiderio Lagrange y Jesús R. Sandoval serían los fotógrafos establecidos en Monterrey con más prestigio entre finales del siglo XIX y principios del XX

    La puesta en escena del nuevo milenio en Puerto Rico

    Get PDF

    La Investigación Siderúrgica en el CENIM

    Get PDF
    Se realiza una revisión de los hitos más relevantes en la investigación siderúrgica realizada en el CENIM en los ultimos 60 añosCSICPeer reviewe

    Shall I post this now? Optimized, delay-based privacy protection in social networks

    Get PDF
    The final publication is available at Springer via http://dx.doi.org/10.1007/s10115-016-1010-4Despite the several advantages commonly attributed to social networks such as easiness and immediacy to communicate with acquaintances and friends, significant privacy threats provoked by unexperienced or even irresponsible users recklessly publishing sensitive material are also noticeable. Yet, a different, but equally significant privacy risk might arise from social networks profiling the online activity of their users based on the timestamp of the interactions between the former and the latter. In order to thwart this last type of commonly neglected attacks, this paper proposes an optimized deferral mechanism for messages in online social networks. Such solution suggests intelligently delaying certain messages posted by end users in social networks in a way that the observed online activity profile generated by the attacker does not reveal any time-based sensitive information, while preserving the usability of the system. Experimental results as well as a proposed architecture implementing this approach demonstrate the suitability and feasibility of our mechanism.Peer ReviewedPostprint (author's final draft

    Habermas: Intervención Social y Política Social

    Get PDF
    La comunicación abordará brevemente la transición desde la Teoría Tradicional a una Teoría Crítica, que supera el dualismo entre teoría y praxis, pensamiento y acción. En definitiva, esclareciendo las relaciones entre ciencia, tecnología y poder. En orden a fundamentar criterios de intervención social del Estado. Habermas evoluciona desde la Teoría Marxista y la crítica del Materialismo Histórico para dar lugar a una nueva concepción del hombre, pasando desde la responsabilidad solidaria a una democracia deliberativa, para crear un modelo que busca fortalecer las condiciones de la comunicación en las sociedades pluralistas, donde tan necesaria es la justicia del Estado de Derecho como la solidaridad de las Redes Ciudadanas. Se abordarán algunos conceptos fundamentales de la Política Social aplicada a aquellos aspectos de la Intervención Social que resultan más relevantes a la hora de definir las intervenciones del Estado. Una democracia deliberativa debe prefigurar unos límites a la imposición de valores para impedir que las ayudas sociales supongan intromisiones en la vida privada de los que las reciben. En conclusión, intentaremos adaptar las reflexiones teóricas a la intervención social de nuestra propia realidad mediterránea

    Dolerse, que siempre es escribir de otra manera.

    Get PDF
    Reseña del libro Dolerse. Textos desde un país herido de Cristina Rivera Garza (Surplus ediciones, México, 2015)
    corecore