104 research outputs found

    Removal of trihalomethane precursors in drinking water treatment processes.

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    In this study the removal efficiency of humic substances by conventional drinking water treatment processes was studied in a full scale operating plant in Windsor, Ontario, Canada over a period of 16 months. A comparison of the removal efficiency of humic substances between conventional and advanced treatment processes such as ozonation (used as an oxidant before filtration) and the addition of granular activated carbon (GAC) was also carried out for the same water source (Detroit River) in a pilot scale treatment plant at the same location. The performance of different treatment processes in removing humic substances was evaluated through the quantification of humic substances and their apparent molecular size distributions (AMSD) in samples taken from the raw water and after each treatment process. The dissolved organic carbon (DOC) and the concentration of the non-humic substances for the water source (Detroit River) were also determined. Results indicate that seasonal variations in humic substances concentration occurred, showing a maximum level during the month of April when the spring turn-over of water bodies took place. These seasonal variations were associated with the corresponding changes in THM concentrations observed during the same period. The fulvic and humic acid composition of humic substances and their THM formation potential (THMFP) were quantified. Their AMSD were determined by the gel permeation chromatography (GPC) and the high performance size exclusion chromatography (HPSEC). The humic substances from the Detroit River were found to be less reactive in forming THMs (μ\mug THM/mg C) when compared with the standard humic substances provided by the International Humic Substances Society (IHSS). Coagulation-sedimentation was the most efficient process of the conventional treatment options in the removal of humic substances. The GAC greatly improved the removal efficiency of not only the humic substances but also of a large fraction of the non-humic substances. The removal of humic substances by the use of ozone as an oxidant before filtration was similar to that obtained by the conventional treatment with prechlorination. The THMFP was determined on water samples from different processes and on their corresponding non-humic fractions. Precursor removal after each process effectively reduced the THMFP in the treated water. The non-humic fractions appeared to be potential contributors to the formation of THMs for high chlorine dosages. Source: Dissertation Abstracts International, Volume: 56-01, Section: B, page: 0389. Adviser: Nihar Biswas. Thesis (Ph.D.)--University of Windsor (Canada), 1994

    Mejora del proceso de asignación del proyecto y excavación para disminuir los tiempos de la fase constructiva de una empresa de servicios de construcción en el distrito de Carabayllo, año 2022

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    El presente trabajo tuvo como objetivo principal determinar la mejora en el proceso de asignación del proyecto y excavación en la disminución de los tiempos de la fase constructiva de una empresa de servicios de construcción en el distrito de Carabayllo, año 2022. El trabajo se desarrolló entre los meses de enero y abril del año 2022 en el distrito de Carabayllo, se encontraron fallas en los procesos de asignación de proyectos y excavación, mediante el diagrama de Ishikawa y Pareto se identificó las causas más relevantes, programándose el avance de obra de los proyectos asignados, se formalizó la entrega de asignación de proyectos y se gestionó los ingresos de los nuevos proveedores para mejorar el proceso de excavación, así mismo, se implementó indicadores de tiempo y proveedores los cuales ayudaron a la mejora de los procesos de la fase constructiva. El resultado para la fase constructiva fue que la disminución en los tiempos de entrega de16 a13 días. Se concluyó que gestionando los procesos de implementación y escogiendo las herramientas de ingeniería adecuadas se solucionaban las causas más relevantes, en este caso el de asignación y excavación en la fase constructiva. Asimismo, las competencias profesionales aplicadas fueron, dar solución a los problemas de la empresa, analizando y clasificándolo mediante las herramientas de ingeniería, gestionando las soluciones para la implementación y ejecución de la mejora

    ACOMPAÑAMIENTO FAMILIAR Y PROCESO DE APRENDIZAJE EN ESTUDIANTES DEL NIVEL PRIMARIO

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    El objetivo de la investigación fue determinar los niveles de relación entre el acompañamiento familiar y el proceso de aprendizaje en los estudiantes del nivel primario de la institución educativa  N° 10366 del distrito de Sócota-Cajamarca. Estudio no experimental, de tipo descriptiva-correlacional, de enfoque mixto, con una población de 108 estudiantes de quinto y sexto grado de primaria y 6 profesores de los mismos grados, aplicando un cuestionario y entrevista estructurada, de estadística descriptiva y cuadro de doble entrada para los resultados cualitativos. En los resultados de la investigación se encontró un nivel de relación positivo medio en cuanto a las acciones de asistencia regular a clases, supervisión de tareas y participación de los padres de familia; sin embargo, existen debilidades que se requiere fortalecer para mejorar esas acciones cambiando según la modalidad de estudios presencial o no presencial, llegando a  determinar una relación estadísticamente comprobada entre las variables del acompañamiento familiar y proceso de aprendizaje, dando a entender que los padres cumplen su responsabilidad y deber de acompañar, apoyar y retroalimentar las acciones en la vida escolar

    Análisis económico del negocio taxis que operan en la ciudad de Tunja durante el primer semestre de 2019

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    Se desarrolla un proyecto de investigación meramente académico con el fin de obtener el título: Especialista en Gestión de Proyectos. El desarrollo de este trabajo se enfoca en realizar un análisis económico del negocio taxis que operan en la ciudad de Tunja durante el primer semestre de 2019. Para esto, se utilizó un enfoque cuantitativo e investigación descriptiva puesto que este estudio se desarrolló mediante recolección de información (encuestas) e interpretación de resultados.A purely academic research project is developed in order to obtain the title: Specialist in Project Management. The development of this work focuses on conducting an economic analysis of the business taxis that operate in the city of Tunja during the first semester of 2019. For this, a quantitative approach and descriptive research was used since this study was developed by collecting information (surveys) and interpretation of results

    Photovoltaic power resource at the Atacama Desert under climate change

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    The Atacama desert is a region with exceptional conditions for solar power production. However, despite its relevance, the impact of climate change on this resource in this region has barely been studied. Here, we use regional climate models to explore how climate change will affect the photovoltaic solar power resource per square meter ( ) in Atacama. Models project average reductions in of 1.5% and 1.7% under an RCP8.5 scenario, respectively, for 2021-2040 and 2041-2060. Under RCP2.6 and the same periods, reductions range between 1.2% and 0.5%. Also, we study the contribution to future changes in of the downwelling shortwave radiation, air temperature and wind velocity. We find that the contribution from changes in wind velocity is negligible. Future changes of downwelling shortwave radiation, under the RCP8.5 scenario, cause up to 87% of the decrease of for 2021-2040 and 84% for 2041-2060. Rising temperatures due to climate change are responsible for drops in ranging between 13%–19% under RCP2.6 and 14%–16% under RCP8.5.Xunta de Galicia | Ref. ED431C 2021/44Universidad de Vigo/CISUGMinisterio de Ciencia e Innovación | Ref. IJC2020-043745-IMinisterio de Universidade

    Enfermedades en hortalizas en el Valle Inferior del Río Negro. Lechuga en invernadero

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    La producción hortícola en el valle inferior del río Negro siempre ha estado marcada por la estacionalidad. En el caso de la lechuga, el cultivo a campo se realiza principalmente durante la primavera y verano mientras la realización en invernadero permite su cultivo durante todo el año. Esta estacionalidad de los cultivos es lo que ha favorecido el aumento de la superficie de invernaderos y por ende de la producción de lechuga durante otoño-invierno.EEA Valle InferiorFil: Baffoni, Patricia Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Valle Inferior; ArgentinaFil: Doñate, María Teresa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Valle Inferior; ArgentinaFil: Muzi, Enrique. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Valle Inferior; ArgentinaFil: Sidoti Harttmann, Brunilda. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Valle Inferior; ArgentinaFil: Alarcón, Aldo José. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Valle Inferior; ArgentinaFil: Seba, Nicolas. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Valle Inferior; Argentin

    Características de la personalidad de jóvenes jugadores de baloncesto (15-under)

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    El objetivo de este trabajo fue estudiar los rasgos de personalidadde los jóvenes jugadores de baloncesto de 13-15 años (n=54) a través de laevaluación de las dimensiones del cuestionario de personalidad BFQ-NA,para niños y adolescentes. Se trata de un estudio no experimental en el quese emplea un diseño transeccional o transversal descriptivo. Los resultadosobtenidos permiten afirmar que los jugadores seleccionados para la muestrase caracterizan por ser personas: a) perseverantes, tenaces y exigentes, b)abiertas a la novedad, creativas, espontáneas y cultas, c) con valores normalesde sociabilidad, seguridad y entusiasmo, d) amables, honestas, educadasy e) tranquilas, serenas y poco irritables

    Quantitative trait loci (QTLs) analysis of palm oil fatty acid composition in an interspecific pseudo-backcross from Elaeis oleifera (HBK) Cort,s and oil palm (Elaeis guineensis Jacq.)

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    IATE Axe 4 : Biotechnologie microbienne et enzymatique des lipides et des agropolymèresWe chose an Elaeis interspecific pseudo-backcross of first generation (E. oleifera x E. guineensis) x E. guineensis to identify quantitative trait loci (QTLs) for fatty acid composition of palm oil. A dense microsatellite linkage map of 362 loci spanned 1.485 cM, representing the 16 pairs of homologous chromosomes in the Elaeis genus from which we traced segregating alleles from both E. oleifera and E. guineensis grandparents. The relative linear orders of mapped loci suggested the probable absence of chromosome rearrangements between the E. oleifera and E. guineensis genomes. A total of 19 QTL associated to the palm oil fatty acid composition were evidenced. The QTL positions and the species origin as well as the estimated effects of the QTL marker alleles were in coherence with the knowledge of the oil biosynthesis pathway in plants and with the individual phenotypic correlations between the traits. The mapping of chosen Elaeis key genes related to oleic acid C18:1, using intra-gene SNPs, supported several QTLs underlying notably FATA and SAD enzymes. The high number of hyper-variable SSR loci of known relative linear orders and the QTL information make these resources valuable for such mapping study in other Elaeis breeding materials

    Repeated out-of-Africa expansions of Helicobacter pylori driven by replacement of deleterious mutations

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    Erratum in: Nat Commun. 2023 Mar 20;14(1):1539. doi: 10.1038/s41467-023-37302-5.Helicobacter pylori lives in the human stomach and has a population structure resembling that of its host. However, H. pylori fromEurope and the Middle East trace substantially more ancestry from modern African populations than the humans that carry them. Here, we use a collection of Afro-Eurasian H. pylori genomes to show that this African ancestry is due to at least three distinct admixture events. H. pylori from East Asia, which have undergone little admixture, have accumulated many more non-synonymous mutations than African strains. European and Middle Eastern bacteria have elevated African ancestry at the sites of these mutations, implying selection to remove them during admixture. Simulations show that population fitness can be restored after bottlenecks bymigration and subsequent admixture of small numbers of bacteria from non-bottlenecked populations. We conclude that recent spread of African DNA has been driven by deleterious mutations accumulated during the original out-of-Africa bottleneck.This work was supported by Sequencing Grants-in-aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan (221S0002, 18KK0266, 19H03473, 21H00346 and 22H02871) to Y.Y. F.F.V. is financed by FCT through Assistant Researcher grant CEECIND/03023/2017 and a project grant PTDC/BTM-TEC/3238/ 2020. I.K. studentship was funded by the National Strategic Reference Framework Operational Program “Competitiveness, Entrepreneurship and Innovation” (NSRF 2014-2020, project No. MIS5002486) and sequencing of strains was supported by the InfeNeutra Project (NSRF 2007-2013, project no. MIS450598) of the Ministry of Culture and Edu- cation, Greece. K.T. and the sequencing of KI isolates was supported by Erik Philip-Sörensen Foundation grant G2016-08, and Swedish Society for Medical research (SSMF). All primary bioinformatics and parts of the comparative genomics were performed on resources provided by Swedish National Infrastructure for Computing (SNIC) through Uppsala Multidisciplinary Center for Advanced Computational Science (UPPMAX) under projects snic2018-8-24 and uppstore2017270. Work by S.S. was supported by the German Research Foundation (DFG, project number 158 989 968–SFB 900/A1) and by the Bavarian Ministry of Sci- ence and the Arts in the framework of the Bavarian Research Network “New Strategies Against Multi-Resistant Pathogens by Means of Digital Networking—bayresq.net”. D.F. was supported by Shanghai Municipal Science and Technology Major Project No. 2019SHZDZX02.info:eu-repo/semantics/publishedVersio
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