2,655 research outputs found

    Pilot-scale continuous flow granular reactor for the treatment of extremely low-strength recirculating aquaculture system wastewater

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    To avoid toxic ammonium and nitrite concentrations in aquaculture systems is crucial to maintain the fish production. When recirculating aquaculture systems (RAS) operate in freshwater farms during the dry seasons, the concentrations of these pollutants increase. The objective of the present study is the evaluation of a Continuous Flow Granular Reactor (CFGR) for the treatment of freshwater RAS stream at pilot-scale during two consecutive dry seasons. The CFGR was fed with a extremely low-strength recirculation stream of a trout farm (0.12–1.84 mg NH4+-N/L and 2.2–8.14 mg C/L). Two different configurations were evaluated. The first configuration consisted on a CFGR fed from the bottom, being the up-flow velocity the only shear force to mix the biomass. The second configuration incorporated a mechanical stirrer and a sieve to improve the biomass mixing and retention. The CFGR was operated at short hydraulic retention times (HRT) which ranged from 11 to 68 min. The configuration with a mechanical stirrer and sieve was optimal in terms of biomass retention and nitrogen removal performance. Despite the low nitrogen and organic matter concentrations, granulation was achieved in 55 days, with an average granule diameter up to 0.47 mm. Ammonium and nitrite removal percentages up to 81% and 100% were achieved, respectively. The ammonium and nitrite production rate in the trout farm were lower than the removal achieved by the CFGR, which makes the implementation of this system appropriated to maintain the concentration of these compounds below toxic levels for rainbow trout.info:eu-repo/semantics/publishedVersio

    The need for increased protection of Antarctica's inland waters

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    Protection of Antarctica's biodiversity and ecosystem values is enshrined in the Protocol on Environmental Protection to the Antarctic Treaty, which provides for the designation of Antarctic Specially Protected Areas (ASPAs) to areas with outstanding values. Concern has been raised that existing ASPAs fail to prioritize areas to maximize the likelihood of ensuring the long-term conservation of Antarctic ecosystems and biodiversity. The absence of systematic and representative protection is particularly acute for inland aquatic ecosystems, which support a disproportionate amount of inland biodiversity. This paper promotes the case for overt inclusion of inland waters as a critical component of a representative protected area framework for Antarctica, thereby addressing their current underrepresentation. We set out a structured approach to enable the selection of representative freshwater systems for inclusion in the ASPA framework that, with modification, could also be applied across other Antarctic habitats. We acknowledge an overall lack of information on the biogeography of inland aquatic diversity and recommend increased use of remote data collection along with classification tools to mitigate this, as well as the need for the consideration of catchment-scale processes. Changes that accompany contemporary and anticipated climate change make the need for the conservation of representative biodiversity increasingly urgen

    Evaluation of two different granular sludge reactor configurations for the treatment of freshwater aquaculture streams

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    Two aerobic distinct granular sludge reactors were operated to treat freshwater aquaculture streams at laboratory-scale: An Expanded Granular Sludge Bed(EGSB)reactor operated in continuous mode and an Aerobic Granular Sludge -Sequencing Batch Reactor(AGS-SBR) operated as a sequencing batch reactor. Both units were fed with low ammonium concentrations (2.5 mg N/L). Granular biomass accumulated in both reactors. With the imposed operational conditions, nitrogen removal was of 10 -20 % and 80 % for the EGSB and AGS-SBR, respectively.info:eu-repo/semantics/publishedVersio

    New 9-Terpenyl(7-Terpenyl)Purines: synthesis and cytotoxicity

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    The purine ring system is one of the most widely distributed N-heterocycles in Nature [1] and many structurally modified purine nucleosides and nucleotides have activities ranging from antineoplastic and antiviral to antihypertensive, antiasthmatic, antituberculosis, etc [2]. Among the purine derivatives, we have put our attention on natural N-alkylpurines such as the asmarines or agelasimines, a group of secondary metabolites isolated from marine sponges with very interesting biological properties [3]. They have a diterpenoid moiety attached to the N-7 nitrogen atom of an adenine and are usually isolated in very small quantities, which limited their structure-activity relationship studies. Our research group has been involved for years in the design, synthesis and biological evaluation of cytotoxic compounds related to natural products, including the chemoinduction of bioactivity on inactive terpenoids [4]. These diterpenoid include compounds such as communic or cupressic acids that bear decaline moieties very close to those present in the above-mentioned marine natural products. These facts prompted us to design and prepare new terpenylpurine derivatives starting from natural monoterpenoids and diterpenoids, commercially available or isolated from their natural sources and transformed into appropriate alkylated agents. Thus, we have prepared purines alkylated at N-7 and N-9 positions with isoprenoids, monoterpenoids and diterpenoids, using two different synthetic approaches: from 6-chloropurine or from 4,5-diamine-6-chloropyrimidine. The structure of the synthesized purines are shown in the following figure. The purine analogues synthesized have been evaluated for their cytotoxicity against four tumour human cell lines (breast, non-small lung, cervical and hepatocellular carcinoma) and non-tumour cells (porcine liver primary cells). The most cytotoxic derivatives were those with a diterpenoid rest on the purine. The results obtained allowed to draw conclusions on the structure-activity relationship of the compounds in order to evaluate the influence of the terpenyl size on their cytotoxic properties

    The XMM-Newton survey in the H-ATLAS field

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    Wide-area X-ray and far-infrared surveys are a fundamental tool to investigate the link between AGN growth and star formation, especially in the low-redshift universe (z ≲ 1). The Herschel Terahertz Large Area survey (H-ATLAS) has covered 550 deg2 in five far-infrared and sub-mm bands, 16 deg2 of which have been presented in the Science Demonstration Phase (SDP) catalogue. Here we introduce the XMM-Newton observations in the H-ATLAS SDP area, covering 7.1 deg2 with flux limits of 2 × 10-15, 6 × 10-15, and 9 × 10-15 erg s-1 cm-2 in the 0.5−2, 0.5−8, and 2−8 keV bands, respectively. We present the source detection and the catalogue, which includes 1700, 1582, and 814 sources detected by EMLDetect in the 0.5−8, 0.5−2, and 2−8 keV bands, respectively; the number of unique sources is 1816. We extract spectra and derive fluxes from power-law fits for 398 sources with more than 40 counts in the 0.5−8 keV band. We compare the best-fit fluxes with those in the catalogue, which are obtained assuming a common photon index of Γ = 1.7; we find no bulk difference between the fluxes and a moderate dispersion of s = 0.33 dex. Using the fluxes from the spectral fits wherever possible, we derive the 2−10 keV Log N−Log S, which is consistent with a Euclidean distribution. Finally, we release the computer code for the tools developed for this project.P.R. acknowledges a grant from the Greek General Secretariat of Research and Technology in the framework of the programme Support of Postdoctoral Researchers. A.D.M. acknowledges financial support from the UK Science and Technology Facilities Council (ST/I001573/I). F.J.C. acknowledges financial support by the Spanish Ministry of Economy and Competitiveness through grant AYA2012-31447.Peer Reviewe

    Utility of a thematic network in primary health care: a controlled interventional study in a rural area

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    BACKGROUND: UniNet is an Internet-based thematic network for a virtual community of users (VCU). It supports a virtual multidisciplinary community for physicians, focused on the improvement of clinical practice. This is a study of the effects of a thematic network such as UniNet on primary care medicine in a rural area, specifically as a platform of communication between specialists at the hospital and doctors in the rural area. METHODS: In order to study the effects of a thematic network such as UniNet on primary care medicine in a rural area, we designed an interventional study that included a control group. The measurements included the number of patient displacements due to disease, number of patient hospital stays and the number of prescriptions of drugs of low therapeutic utility and generic drug prescriptions by doctors. These data were analysed and compared with those of the control center. RESULTS: Our study showed positive changes in medical practice, reflected in the improvement of the evaluated parameters in the rural health area where the interventional study was carried out, compared with the control area. We discuss the strengths and weaknesses of UniNet as a potential medium to improve the quality of medical care in rural areas. CONCLUSION: The rural doctors had an effective, useful, user-friendly and cheap source of medical information that may have contributed to the improvement observed in the medical quality indices

    Disacáridos cianogénicos y benzoilados en hojas de Psydrax Locuples

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    Las plantas del género Psydrax y otras Rubiaceas relacionadas son usadas en la medicina popular africana frente a malaria, fiebre, dolores de cabeza, reumatismos, diarrea, conjuntivitis, micosis y otros cuadros infecciosos. Apenas existe bibliografía fitoquímica sobre este género: únicamente tres compuestos en la especie Psydrax livida [1]. Recientemente hemos comunicado las propiedades antioxidantes y citotóxicas de los extractos obtenidos de hojas de Psydrax locuples, planta arbórea utilizada particularmente en Mozambique para tratar la “doença da lua” en niños y recién nacidos, un síndrome relacionado con la epilepsia caracterizado por fiebre, vómitos, diarrea, dolor de cabeza y cólicos abdominales [2]. A partir del extracto de acetato de etilo de sus hojas se han aislado, mediante sucesivas cromatografías en columna y cromatografías en capa fina preparativas, varios disacáridos acetilados con estructura de (2R)-β-D-apiofuranosil-(1→6)-β-Dglucopiranosa. Estos disacáridos se pueden clasificar en dos familias en función de si el hidroxilo de la posición 1 de la β-D-glucopiranosa se encuentra benzoilado o si se encuentra unido a un residuo de mandelonitrilo formando glicósidos cianogénicos relacionados con la oxyanthina presente en Psydrax livida [1].Estos disacáridos son prácticamente desconocidos en el reino vegetal, tanto los benzoilados como los cianogénicos, siendo la mayoría nuevos productos naturales

    Short and long term orange dye effects over AOB and anammox activities

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    "This is the pre-peer reviewed version of the following article: Val del Río, A., Stachurski, A., Méndez, R., Campos, J. L., Surmacz-Górska, J., & Mosquera-Corral, A. (2017). Short- and long-term orange dye effects on ammonium oxidizing and anammox bacteria activities. Water Science and Technology, 76(1), 79-86, which has been published in final form at [http://dx.doi.org/10.2166/wst.2017.186. This article may be used for non-commercial purposes in accordance with IWA Publishing."In this research work the effects of orange azo dye over ammonia oxidizing bacteria (AOB) and anammox bacteria activities were tested. Adsorption onto the biomass was detected with both types of biomass however no biological decolourization occurred. Performed batch tests indicated that concentrations lower than 650 mgorange/L stimulated AOB activity while anammox bacteria activity was inhibited at concentrations higher than 25 mgorange/L. Long-term performance of both processes was tested in the presence of 50 mgorange/L. In the case of the partial nitritation process both the biomass concentration and the specific AOB activity increased after 50 days of orange azo dye addition. Regarding the anammox process, specific activity decreased down to 58% after 12 days of operation; however, initial values were restored 54 days after stopping the dye additionThis work was funded by the European Union through the Cost Action (ES-10755) and by the Spanish Government through FISHPOL (CTQ2014-55021-R) and GRANDSEA (CTM2014-55397-JIN) projects co-funded by FEDER. The authors from the USC belong to CRETUS (AGRUP2015/02) and the Galician Competitive Research Group (GRC 2013-032), programs co-funded by FEDERNO

    The Spanish Mediterranean Fishing Guilds (Cofradias): An Example of Collaborative Management with a Key Role in Sustainable Fisheries

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    [EN] The management of Spanish coastal fisheries is based on a mixed model where the centralised action of the government is combined with the self-organisation of fishers in cofradias (guilds). These institutions have economic and political functions, intermediating between the State and the fishing sector and mediating in the conflicts that may occur. They also have welfare and mutualist tasks. This original and traditional co-management model is part of the social capital of traditional Spanish fishing. The aim of this article is to explore the possibilities of these Spanish fishers' organisations in order to improve the legitimacy of the fishery system and the sustainability of fisheries. Our hypothesis is that updating and adapting some aspects of the cofradias model could produce efficient forms of collaborative management and lead to improvements in the sustainability of fisheries. To validate this hypothesis the study analysed 69 face-to-face interviews in 21 Spanish-Mediterranean guilds. The analysis focused on three core aspects: the control of fishing resources; the integration of fishing knowledge in the management system; and, finally, the guilds contribution to the legitimacy of the system in the eyes of the fishers.This work was supported by National Plan for Scientific and Technological Research and Innovation (Spanish Economy and Competitiveness Ministry). Research Project CSO2016-76135-P. There is no conflict of interest declared in this article.Herrera-Racionero, P.; Lizcano, E.; Miret Pastor, LG.; Mascarell, Y. (2019). The Spanish Mediterranean Fishing Guilds (Cofradias): An Example of Collaborative Management with a Key Role in Sustainable Fisheries. Fisheries. 44(4):172-182. https://doi.org/10.1002/fsh.10224S172182444Alegret J. L.1999.Gestión comunitaria cogestión y mercado. 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Sampling Knowledge: The Hermeneutics of Snowball Sampling in Qualitative Research. International Journal of Social Research Methodology, 11(4), 327-344. doi:10.1080/13645570701401305Ostrom, E. (2009). A General Framework for Analyzing Sustainability of Social-Ecological Systems. Science, 325(5939), 419-422. doi:10.1126/science.1172133Pita, P., Fernández-Vidal, D., García-Galdo, J., & Muíño, R. (2016). The use of the traditional ecological knowledge of fishermen, cost-effective tools and participatory models in artisanal fisheries: Towards the co-management of common octopus in Galicia (NW Spain). Fisheries Research, 178, 4-12. doi:10.1016/j.fishres.2015.07.021Producer organisations are officially recognised bodies set up by fishery or aquaculture producers. They play an essential role in running the European Common Fisheries Policy.State Marine Fishery Law: Law 3/2001 of March 26 2001. BOE (State Official Gazette) number 75. Available:https://www.boe.es/buscar/doc.php?id=BOE-A-2001-600
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