307 research outputs found

    Mejora del comportamiento dinámico de puentes de ferrocarril mediante reaccionamiento con amortiguadores fluido-viscosos

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    This research work is devoted to the problem of excessive vertical vibrations that short to medium-span railway bridges may experiment due to resonance phenomena. A new alternative based on externally increasing the overall damping of the structure by retrofitting the deck with fluid-viscous dampers is proposed in order to reduce detrimental levels of transverse acceleration to admissible ones. This solution could substitute a classical strengthening process or even the complete demolition and replacement of the deck in existing structures under new traffic requirements such as an increase in the speed of the line. A particular configuration of the retrofitting system is proposed which allows the transformation of the vertical oscillations that the deck experiments under the circulation of the railway vehicles into elongation rates of the devices, leading to energy dissipation and the subsequent reduction of the super-structure resonant response. The proposed system could be installed in the original structure and maintained without interfering with everyday traffic

    Differential Gene Expression in Liver, Gill, and Olfactory Rosettes of Coho Salmon (Oncorhynchus kisutch) After Acclimation to Salinity.

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    Most Pacific salmonids undergo smoltification and transition from freshwater to saltwater, making various adjustments in metabolism, catabolism, osmotic, and ion regulation. The molecular mechanisms underlying this transition are largely unknown. In the present study, we acclimated coho salmon (Oncorhynchus kisutch) to four different salinities and assessed gene expression through microarray analysis of gills, liver, and olfactory rosettes. Gills are involved in osmotic regulation, liver plays a role in energetics, and olfactory rosettes are involved in behavior. Between all salinity treatments, liver had the highest number of differentially expressed genes at 1616, gills had 1074, and olfactory rosettes had 924, using a 1.5-fold cutoff and a false discovery rate of 0.5. Higher responsiveness of liver to metabolic changes after salinity acclimation to provide energy for other osmoregulatory tissues such as the gills may explain the differences in number of differentially expressed genes. Differentially expressed genes were tissue- and salinity-dependent. There were no known genes differentially expressed that were common to all salinity treatments and all tissues. Gene ontology term analysis revealed biological processes, molecular functions, and cellular components that were significantly affected by salinity, a majority of which were tissue-dependent. For liver, oxygen binding and transport terms were highlighted. For gills, muscle, and cytoskeleton-related terms predominated and for olfactory rosettes, immune response-related genes were accentuated. Interaction networks were examined in combination with GO terms and determined similarities between tissues for potential osmosensors, signal transduction cascades, and transcription factors

    Absorption, distribution and accumulation of nitrogen applied at different phenological stages in southern highbush blueberry (Vaccinium corymbosum interspecific hybrid)

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    Southern highbush blueberry has an early harvesting and then a long period of vegetative growth until dormancy, compared to highbush and rabbiteye blueberries. Nitrogen requirements could be different because of this specific early harvesting. Absorption of 15N enriched ammonium sulfate was compared at five phenological stages from bud swell to pre-dormancy in two years old plants of the cultivars Star and ÓNeal. Plants grown in pots were irrigated with ammonium sulfate solution (15N). Five plants for each application date were excavated and separated in parts (roots, canes, leaves, flowers, fruits or floral buds). Samples were taken three weeks after application from bud swell to pre-harvest treatment, and three month after for post-harvest and pre-dormancy treatment. Each tissue were dried and weighed before and after, and analyzed for 15N content, N content and N %….N%, and in leaves were also determined macro and micro nutrients. Nitrogen fertilization at bud swell is effective, even for the ÓNeal cultivarthat present floral bud break in absence of leaves. Post-harvest fertilization contribute N for summer vegetativegrowth which would influence the floral buds development next year, Nitrogenstorage at this time would led to the improved floral behavior next year. Nitrogen losses risk is lower at post-harvestfertilization.Fil: Pescie, María A.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Borda, Marcela P.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Ortiz, Daniela P.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Landriscini, María Rosa. Universidad Nacional del Sur. Departamento de Agronomía. Área Suelos y Aguas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Lavado, Raul Silvio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentin

    Projected increases in the annual flood pulse of the Western Amazon

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    The impact of a changing climate on the Amazon basin is a subject of intensive research because of its rich biodiversity and the significant role of rainforests in carbon cycling. Climate change has also a direct hydrological impact, and increasing efforts have focused on understanding the hydrological dynamics at continental and subregional scales, such as the Western Amazon. New projections from the Coupled Model Inter-comparison Project Phase 5 ensemble indicate consistent climatic warming and increasing seasonality of precipitation in the Peruvian Amazon basin. Here we use a distributed land surface model to quantify the potential impact of this change in the climate on the hydrological regime of the upper Amazon river. Using extreme value analysis, historical and future projections of the annual minimum, mean, and maximum river flows are produced for a range of return periods between 1 and 100 yr. We show that the RCP 4.5 and 8.5 scenarios of climate change project an increased severity of the wet season flood pulse (7.5% and 12% increases respectively for the 100 yr return floods). These findings agree with previously projected increases in high extremes under the Special Report on Emissions Scenarios climate projections, and are important to highlight due to the potential consequences on reproductive processes of in-stream species, swamp forest ecology, and socio-economy in the floodplain, amidst a growing literature that more strongly emphasises future droughts and their impact on the viability of the rainforest system over greater Amazonia

    A combined view on precipitation and temperature climatology and trends in the southern Andes of Peru

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    In the southern Peruvian Andes, communities are highly dependent on climatic conditions due to the mainly rain-fed agriculture and the importance of glaciers and snow melt as a freshwater resource. Longer-term trends and year-to-year variability of precipitation or temperature severely affect living conditions. This study evaluates seasonal precipitation and temperature climatologies and trends in the period 1965/66–2017/18 for the southern Peruvian Andes using quality-controlled and homogenized station data and new observational gridded data. In this region, precipitation exhibits a strong annual cycle with very dry winter months and most of the precipitation falling from spring to autumn. Spatially, a northeast–southwest gradient in austral spring is observed, related to an earlier start of the rainy season in the northeastern partof the study area. Seasonal variations of maximum temperature are weak withan annual maximum in austral spring, which is related to reduced cloud coverin austral spring compared to summer. On the contrary, minimum tempera-tures show larger seasonal variations, possibly enhanced through changes inlongwave incoming radiation following the precipitation cycle. Precipitationtrends since 1965 exhibit low spatial consistency except for austral summer,when in most of the study area increasing precipitation is observed, and in aus-tral spring, when stations in the central-western region of the study area regis-ter decreasing precipitation. All seasonal and annual trends in maximum temperature are larger than trends in minimum temperature. Maximum temperature exhibits strong trends in austral winter and spring, whereas minimum temperature trends are strongest in austral winter. We hypothesize, that these trends are related to precipitation changes, as decreasing (increasing) precipita-tion in spring (summer) may enhance maximum (minimum) temperature trends through changes in cloud cover. El Niño Southern Oscillation (ENSO), however, has modifying effects onto precipitation and temperature, and thereby leads to larger trends in maximum temperatures

    A Osteomielite Crónica pode ser o Precedente de uma Infeção por Corynebacterium Diphtheriae

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    INTRODUÇÃO E OBJETIVOS: A infeção por Corynebacterium diphtheriae não toxinogénica tem sido cada vez mais descrita e associada a doença grave e disseminada, como endocardite, artrite séptica e osteomielite1, podendo estar associada a doentes com infeções ósseas ou ar6culares, entre outras. 2 A vacinação não é protetora para C. diphtheriae não toxinogénica. 3 Apresentamos o caso clínico de uma doente com fractura exposta do úmero com 1 ano de evolução com sinais de osteomielite crónica e isolamento de C. diphtheriae, S. aureus e S. pyogenes. CASO CLÍNICO: Rapariga de 11 anos Natural e residente na Guiné Desconhece-se estado vacinal. Desconhece-se contexto epidemiológico. Foi fieto: DESBRIDAMENTO e fistulectomia FLUCLOXACILINA e RIFAMPICINA 12semanas + PENICILINA 3 semanas; boa evolução aos 3 meses. CONCLUSÃO: A difteria cutânea é causada por estirpes de Corynebacterium diphteriae, produtoras ou não de toxina. Caracterizam-se por úlceras cutâneas crónicas, que servem como reservatório. A probabilidade de envolvimento faríngeo é rara. É possível, que possa ter algum papel como agente patogénico na osteomielite crónica, em co-infeção com S. aureus2, tal como no caso apresentado.info:eu-repo/semantics/publishedVersio

    Orthogonally bifunctionalised polyacrylamide nanoparticles: a support for the assembly of multifunctional nanodevices

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    Polyacrylamide nanoparticles bearing two orthogonal reactive functionalities were prepared by reverse microemulsion polymerisation. Water-soluble photosensitisers and peptide or carbohydrate moieties were sequentially attached to the new nanospecies by orthogonal conjugations based on copper- catalysed azide-alkyne cycloaddition and isothiocyanate chemistry

    Assessment of present and future water security under anthropogenic and climate changes using WEAP model in the Vilcanota-Urubamba catchment, Cusco, Perú

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    Water is an essential resource for social and economic development. The availability of this resource is constantly threatened by the rapid increase in its demand. This research assesses current (2010–2016), short- (2017–2040), middle- (2041–2070), and long-term (2071–2099) levels of water security considering socio-economic and climate change scenarios using the Water Evaluation and Planning System (WEAP) in Vilcanota-Urubamba (VUB) catchment. The streamflow data of the Pisac hydrometric station were used to calibrate (1987–2006) and validate (2007–2016) the WEAP Model applied to the VUB region. The Nash Sutcliffe efficiency values were 0.60 and 0.84 for calibration and validation, respectively. Different scenarios were generated for socio-economic factors (population growth and increased irrigation efficiency) and the impact of climate change to evaluate their effect on the current water supply system. The results reveal that water availability is much higher than the current demand in the VUB for the period (2010–2016). For short-, middle- and long term, two scenarios were considered, “Scenario 1” (RCP 4.5) and “Scenario 2” (RCP 8.5). Climate change scenarios show that water availability will increase. However, this increase will not cover the future demands in all the sub-basins because water availability is not evenly distributed in all of the VUB. In both scenarios, an unmet demand was detected from 2050. For the period 2071–2099, an unmet demand of 477 hm3/year for “Scenario 1” and 446 hm3/year for “Scenario 2” were estimated. Because population and agricultural demands are the highest, the effects of reducing the growth rate and improving the irrigation structure were simulated. Therefore, two more scenarios were generated “Scenario 3” (RCP 4.5 with management) and “Scenario 4” (RCP 8.5 with management). This socio-economic management proved to be effective in reducing the unmet demand up to 50% in all sub-basins for the period 2071–2099

    Photonic-based integrated sources and antenna arrays for broadband wireless links in terahertz communications

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    This paper analyzes integrated components for ultra-broadband millimeter-wave wireless transmitters enabling the 5 G objective to increase the wireless data rates 10x to 100x . We have pursued the photonic-based approach to generate the millimeter-wave carrier (approximate to 97GHz in this paper) through photomixing. We have achieved up to 10 Gb s(-1) data rate using an OOK modulation format (to reduce latency) and either direct detection (DD) or coherent detection. We show that coherent detection enables a sensitivity improvement of 17 dB over DD. We also demonstrate in this work that such improvement can be achieved using as the transmitter a novel integrated antenna array-the self-complementary chessboard array. This avoids the use of complex coherent schemes at the receiver, enabling simple DD for ultra-broadband links.The authors acknowledge Dr David Gonzalez Ovejero for fruitful discussions on antenna simulation. This work has been financially supported by Ministerio de Economia, Industria y Competitividad iTWIT Proyect with references TEC2016-76 997-C3-2-R and TEC2016-76 997-C3-3-R. Authors also acknowledge Ayuda Fundacion BBVA a Investigadores y Creadores Culturales 2016' and 'Estancias de movilidad de profesores PRX16/00 021'

    Atributos que determinan la elecci?n de viviendas por adultos j?venes de 25 a 35 a?os en Lima Metropolitana

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    En este estudio se investiga los atributos que determinan la elecci?n de vivienda por parte de los jovenes adultos entre los 25 a. 35 a?os en Lima Metropolitana. En primera instancia, los atributos que se consideraron se recogieron de literatura existente en trabajos de investigaci?n de pa?ses europoeos y del medio oriente; los cuales se filtraron con la realidad peruana, obteni?ndose un total de quince atributos con dos niveles que se categorizan en atributos b?sicos, adicionales y de entorno. La herramienta utilizada para la investigaci?n es el an?lisis conjunto, la muestra depurada es de 144 encuestados a los cuales se les pregunt? su nivel de preferencias por determinado perfil, obteniendose un total de 2304 perfiles evaluados. Los resultados obtenidos muestran la mayor utilidad de atributos como ?rea, precio, cercan?a al trabajo y estacionamiento. Tambi?n podemos decir que el comportamiento de individuos con caracter?sticas sociodemogr?ficas homog?neos no necesariamente son similares, mediante el cruce de los atributos y el perfil sociodemogr?fico, incluso, al analizar la muestra se puede observar que los comportamientos del individuo se extrapolan en los dos niveles siguiendo preferencias en sentidos contrarios incluso con perfil homog?neos en base al cual los expertos del sector desarrollan los productos inmobiliarios
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