40 research outputs found

    Application of Headspace Solid-Phase Microextraction for Determination of Chloro-Organic Compounds in Sewage Samples

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    Solid phase microextraction (SPME) has been optimized and applied to the determination of the volatile halogenated compounds (VHCs) and semi-volatile halogenated compounds (SVHCs). Three types of SPME fiber coated with different stationary phases (PDMS–100 μm, CAR/PDMS-75 μm, PDMS/DVB–65 μm) were used to examine their extraction efficiencies for the compounds tested. Experimental parameters such as the selection of SPME coatings, extraction time, and addition of salts were studied. The carboxen-polydimethylsiloxane (CAR/PDMS) fiber appears to be the most suitable for the determination of VHCs. Analytical parameters such as linearity, limit of detection, and precision were also evaluated. Application of ECD detector for the determination of VHCs and SVHCs allows their determination on the low concentration level, ranging from 0.005 to 0.8 μg/L−1. The HS-SPME-GC/ECD procedure gave good analytical precision expressed as relative standard deviation (RSD) (ranged from 5.08% to 8.07%) for a concentration level of 5 μg/L−1 and good linearity (r2 > 0.98) in a wide calibration range. The applied HS-SPME-GC/ECD method was found to be a quick and effective technique for the determination of microtrace amounts of volatile and semi-volatile halogenated compounds in samples containing high amounts of various organic compounds

    Collaborative platform based on standard services for the semi-automated generation of the 3d city model on the cloud

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    Publisher Copyright: © 2018 Taylor & Francis Group, London.The urban 3D model is increasingly recognized as the adequate support to integrate, harmonize and store the information of a city and make it accessible to all stakeholders (citizens, city managers, companies or researchers). These models facilitate the cooperation of experts in different areas, contributing their knowledge in the generation of a single model. Urban 3D models will allow transforming urban management processes. One example of such processes is the Special Interior Reform Plans (PERI). These urban management processes are developed by the administration, but require the collaboration of different agents. In addition, they represent a clear example of the need to advance in the integration of heterogeneous data at different scales (building and city). The solution proposed in this article presents a platform based on web services for the collaborative generation of urban 3D models. The platform is composed of an information system based on standard data models (IFC and CityGML) and a web services infrastructure that manages the information and relationships stored in the information system at different levels. Besides, a prototype of 3 applications based on the service infrastructure and developed to support the urban management process is presented. The platform is used and tested in the collaborative generation process of the 3D model of the historic district of the city of Vitoria-Gasteiz (Spain) during the definition, editing and monitoring of the PERI of the historic center of the city.Peer reviewe

    Occurrence and distribution of soil Fusarium species under wheat crop in zero tillage

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    The presence of Fusarium species in cultivated soils is commonly associated with plant debris and plant roots. Fusarium species are also soil saprophytes. The aim of this study was to examine the occurrence and distribution of soil Fusarium spp. at different soil depths in a zero tillage system after the wheat was harvested. Soil samples were obtained at three depths (0-5 cm, 5-10 cm and 10-20 cm) from five crop rotations: I, conservationist agriculture (wheat-sorghum-soybean); II, mixed agriculture/livestock with pastures, without using winter or summer forages (wheat-sorghum-soybean-canola-pastures); III, winter agriculture in depth limited soils (wheat-canola-barley-late soybean); IV, mixed with annual forage (wheat-oat/Vicia-sunflower); V, intensive agriculture (wheat-barley-canola, with alternation of soybean or late soybean). One hundred twenty two isolates of Fusarium were obtained and identified as F. equiseti, F. merismoides, F. oxysporum, F. scirpi and F. solani. The most prevalent species was F. oxysporum, which was observed in all sequences and depths. The Tukey’s test showed that the relative frequency of F. oxysporum under intensive agricultural management was higher than in mixed traditional ones. The first 5 cm of soil showed statistically significant differences (p=0.05) with respect to 5-10 cm and 10-20 cm depths. The ANOVA test for the relative frequency of the other species as F. equiseti, F. merismoides, F. scirpi and F. solani, did not show statistically significant differences (p<0.05). We did not find significant differences (p<0.05) in the effect of crop rotations and depth on Shannon, Simpson indexes and species richness. Therefore we conclude that the different sequences and the sampling depth did not affect the alpha diversity of Fusarium community in this system

    Microfungal composition in an Astelia-Donatia cushion peatland in Tierra del Fuego, Argentina

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    En el Hemisferio Sur las turberas almacenan grandes cantidades de carbono en el suelo. A pesar de su importancia en el ciclo global del carbono, se sabe poco acerca de los procesos de descomposición y su diversidad fúngica. El presente estudio se realizó para describir la composición de hongos filamen - tosos en dos profundidades de una turbera compacta donde las especies vegetales predominantes son Astelia (Asteliaceae) y Donatia (Donatiaceae) en Moat, Tierra del Fuego, Argentina. De 48 muestras procesadas, se obtuvieron 338 aislamientos. Mediante el uso de diferentes metodologías de cultivo, a través de observación microscópica y por métodos moleculares identificamos 38 especies fúngicas y 18 géneros de Ascomycetes y Zygomycetes. Los aislamientos de Ascomycetes fueron los más abundantes, con dominancia de Penicillium y Trichoderma . Se describe la composición fúngica y se comparó la diversidad y equitatividad de las especies a dos profundidades de muestreo. No se encontraron diferencias significativas entre la composición de especies, la diversidad y equitatividad. La turbera estudiada es un ecosistema que presenta alta diversidad de especies fúngicas filamentosas, algunas de ellas descritas en otras turberas en todo el mundo

    Neuromodulation system in closed loop for enhancing the sleep and the memory consolidation

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    Publisher Copyright: © 2019 ACM.Recently, there has been growing interest in analyzing the relationship between sleep quality and brain capacities, in terms of memory consolidation and the possible appearance of degenerative diseases such as dementias, including Alzheimer. This paper presents the development of the neuromodulation closed-loop algorithms for sleep stages, spindles and slow-wave sleep (SWS) detection and stimulation generation based on a single electroencephalography (EEG) signal acquisition with the aim of developing a wearable device easy to wear and easy to use for the users. This work presents the characteristics of the system and the initial results.Peer reviewe
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