64 research outputs found

    Respiratory tract infections caused by Human Coronavirus (HCoVs) in Balearic Islands, 2014

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    Introduction: The main human Coronavirus (HCoVs) involved in human respiratory tract infections are the 229E, NL63, and OC43. Due to the lack of information about these infections in our country, it seemed important to know its impact on acute respiratory disease. Material and Methods: In the period February-April 2014, we have studied the presence of different respiratory viruses in 950 samples (throat swabs and/or nasopharyngeal aspirates) belonging to 674 (70.9%) children (<15 years) and 276 adults (29.1%). The detection of respiratory viruses was performed using commercial automatic real-time PCR system (Anyplex RV16), detecting 16 different viruses. Results: The overall HCoV detected was 4.6% of all samples studied and 7.8% (44 cases) of the positive samples. The 44 HCoVs detected corresponded to 20 HCoV-OC43 (45.4%), 17 HCoV-NL63 (38.6%) and 7 HCoV-229E (15.9%). The HCoVs alone were detected in 25 cases (56.8%) and with other respiratory viruses in 19 (43.2%) cases (coinfections). In the mixed infections, rhinovirus was detected in 11 cases (57.8%), influenzavirus type B in 6 cases (31.5%), adenovirus in 1 case and RSV-A in 1 case. HCoVs were detected in the 26 children (59%) and 18 adults (41%). Of the 44 cases, 13 (29.5%) required hospital admission, No patients infected by HCoVs died as a direct result of respiratory tract infection. Conclusions: This study demonstrates the importance of respiratory infections caused by HCoVs, especially in childrenIntroducción: Los principales coronavirus humanos (HCoVs) causantes de infección respiratoria son el 229E, NL63 y OC43. Debido a la falta de información sobre este tipo de infecciones en nuestra comunidad, nos ha parecido importante conocer su impacto en la enfermedad respiratoria aguda. Material y método: En el período Febrero-Abril de 2014 se ha estudiado la presencia de los diferentes virus respiratorios en 950 muestras clínicas (aspirados nasofaríngeos o frotis faríngeos) peryenecientes a 674 niños (<15 años)(70.9%) y 276 adultos (29.1%). La detección viral se ha realizado mediante una RT-PCR comercial que detecta de forma simultánea y diferencial 16 virus distintos (Anyplex RV16). Resultados: El porcentaje global de detección de los HCoVs fue del 4.6% en todas las muestras estudiadas y del 7.8% (44 casos) en las muestras positivas. Se detectaron 20 OC43 (45.4%), 17 NL63 (38.6%) y 7 229E (15.9%). En 25 casos sólo detectó un HCoV (56.8%) y 19 casos (43.2%) la infección fue mixta. En estas infecciones los virus detectados fueron: rinovirus 11 casos (57.8%), virus gripal tipo B en 6 casos (31.5%), y adenovirus y VRS-A un caso cada uno. Los HCoVs se detectaron en 26 niños (59%) y 18 adultos (41%). De los 44 casos, 13 (29.5%) precisaron de ingreso hospitalario. Ningún paciente falleció como consecuencia de la infección respiratorio por el HCoV. Conclusiones: Este estudio demuestra la importancia de las infecciones respiratorias causadas por los coronavirus humanos, especialmente en niños

    Risk of Leaching in Soils Amended by Compost and digestate from Municipal Solid Waste

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    New European directives have proposed the direct application of compost and digestate produced from municipal solid wastes as organic matter sources in agricultural soils. Therefore information about phosphorus leaching from these residues when they are applied to the soil is increasingly mportant. Leaching experiments were conducted to determine the P mobility in compost and digestate mixtures, supplying equivalent amounts to 100 kg P ha?1 to three different types of soils. The tests were performed in accordance with CEN/TS 14405:2004 analyzing the maximum dissolved reactive P and the kinetic rate in the leachate. P biowaste fractionation indicated that digestate has a higher level of available P than compost has. In contrast, P losses in leaching experiments with soil-compost mixtureswere higher than in soil-digestate mixtures. For bothwastes, therewas no correlation between disolved reactive P lost and the water soluble P.The interaction between soil and waste, the long experimentation time, and the volume of leachate obtained caused the waste?s wettability to become an influential parameter in P leaching behavior. The overall conclusion is that kinetic data analysis provides valuable information concerning the sorption mechanism that can be used for predicting the large-scale behavior of soil systems

    Investigating the effect of previous treatment on wheat biomass over multiple spatial frequencies

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    In this study we use the maximum overlap discrete packet transform (MODWPT) to investigate residual effects on wheat biomass of fertigation treatments applied to a previous crop. The wheat crop covered nine subplots from a previous experiment on melon response to fertigation. Each subplot had previously received a different level of applied nitrogen. Many factors affect wheat biomass, causing it to vary at different spatial frequencies. We hypothesize that these will include residual effects from fertilizer application (at relatively low spatial frequencies) and the local influence of individual plants from the previous melon crop (at high frequency). To test this hypothesis we use the MODWPT to identify the dominant spatial frequencies of wheat biomass variation, and analyse the relationship to both the previous fertilizer application and the location of individual melon plants in the previous crop. The MODWPT is particularly appropriate for this because it allows us first to identify the key spatial frequencies in the wheat biomass objectively and to analyse them, and their relationship to hypothesized driving factors without any assumptions of uniformity (stationarity) of wheat-biomass variation. The results showed that the applied nitrogen dominated the wheat biomass response, and that there was a noticeable component of wheat-biomass variation at the spatial frequency that corresponds to the melon cropping. We expected wheat biomass to be negatively correlated with the position of melons in the previous crop, due to uptake of the applied nitrogen. The MODWPT, which allows us to detect changes in correlation between variables at different frequencies, showed that such a relationship was found across part of the experiment but not uniformly

    Yield, nutrient utilization and soil properties in a melon crop amended with wine-distillery waste

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    In Spain, large quantities of wine are produced every year (3,339,700 tonnes in 2011) (FAO, 2011) with the consequent waste generation. During the winemaking process, solid residues like grape stalks are generated, as well as grape marc and wine lees as by-products. According to the Council Regulation (EC) 1493/1999 on the common organization of the wine market, by-products coming from the winery industry must be sent to alcohol-distilleries to generate exhausted grape marc and vinasses. With an adequate composting treatment, these wastes can be applied to soils as a source of nutrients and organic matter. A three-year field experiment (2011, 2012 and 2013) was carried out in Ciudad Real (central Spain) to study the effects of wine-distillery waste compost application in a melon crop (Cucumis melo L.). Melon crop has been traditionally cultivated in this area with high inputs of water and fertilizers, but no antecedents of application of winery wastes are known. In a randomized complete block design, four treatments were compared: three compost doses consisted of 6.7 (D1), 13.3 (D2) and 20 t compost ha-1 (D3), and a control treatment without compost addition (D0). The soil was a shallow sandy-loam (Petrocalcic Palexeralfs) with a depth of 0.60 m and a discontinuous petrocalcic horizon between 0.60 and 0.70 m, slightly basic (pH 8.4), poor in organic matter (0.24%), rich in potassium (410 ppm) and with a medium level of phosphorus (22.1 ppm). During each growing period four harvests were carried out and total and marketable yield (fruits weighting <1 kg or visually rotten were not considered), fruit average weight and fruit number per plant were determined. At the end of the crop cycle, four plants per treatment were sampled and the nutrient content (N, P and K) was determined. Soil samplings (0-30 cm depth) were carried before the application of compost and at the end of each growing season and available N and P, as well as exchangeable K content were analyzed. With this information, an integrated analysis was carried out with the aim to evaluate the suitability of this compost as organic amendment

    Methodology to assess economic and environmental impacts of nitrogen in fertirrigation systems.

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    To determine the risk of nitrate pollution in agricultural systems have identified several indexes and efficiencies that may lead an effective N fertilizer management for obtain the maximum yield with minimum environmental impact and healt

    Nitrogen uptake dynamics, yield and quality as influenced by nitrogen fertilization in "Piel de sapo" melon.

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    The need to reduce nitrogen (N) fertilizer pollution strengthens the importance of improving the utilization efficiency of applied N to crops. This requires knowledge of crop N uptake characteristics and how fertilization management affects it. A three-year field experiment was conducted from May to September in central Spain to investigate the influence of different N rates, which ranged from 11 to 393 kg ha-1, applied through drip irrigation, on the dynamics of N uptake, nitrogen use efficiency (NUE), fruit yield and quality of a ?Piel de sapo? melon crop (Cucumis melo L. cv. Sancho). Both N concentration and N content increased in different plant parts with the N rate. Leaves had the highest N concentration, which declined by 40-50% from 34-41 days after transplanting (DAT), while the highest N uptake rate was observed from 30-35 to 70-80 DAT, coinciding with fruit development. In each year, NUE declined with increasing N rate. With N fertilizer applications close to the optimum N rate of 90-100 kg ha-1, the fruits removed approximately 60 kg N ha-1, and the amount of N in the crop residue was about 80 kg N ha-1; this serves to replenish the organic nutrient pool in the soil and may be used by subsequent crops following mineralization

    Growth dynamics and yield of melon as influenced by nitrogen fertilizer

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    Nitrogen (N) is an important nutrient for melon (Cucumis melo L.) production. However there is scanty information about the amount necessary to maintain an appropriate balance between growth and yield. Melon vegetative organs must develop sufficiently to intercept light and accumulate water and nutrients but it is also important to obtain a large reproductive-vegetative dry weight ratio to maximize the fruit yield. We evaluated the influence of different N amounts on the growth, production of dry matter and fruit yield of a melon ‘Piel de sapo’ type. A three-year field experiment was carried out from May to September. Melons were subjected to an irrigation depth of 100% crop evapotranspiration and to 11 N fertilization rates, ranging 11 to 393 kg ha –1 in the three years. The dry matter production of leaves and stems increased as the N amount increased. The dry matter of the whole plant was affected similarly, while the fruit dry matter decreased as the N amount was increased above 112, 93 and 95 kg ha –1 , in 2005, 2006 and 2007, respectively. The maximum Leaf Area Index (LAI), 3.1, was obtained at 393 kg ha –1 of N. The lowest N supply reduced the fruit yield by 21%, while the highest increased the vegetative growth, LAI and Leaf Area Duration (LAD), but reduced yield by 24% relative to the N93 treatment. Excessive applications of N increase vegetative growth at the expense of reproductive growth. For this melon type, rates about 90-100 kg ha –1 of N are sufficient for adequate plant growth, development and maximum production. To obtain fruit yield close to the maximum, the leaf N concentration at the end of the crop cycle should be higher than 19.5 g kg –

    Risk of nitrate pollution in agricultural systems

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    Se propone una metodología que nos permita evaluar un óptimo manejo de la fertirrigación integrando aspectos agronómicos y medioambientales

    Impact of nitrogen uptake on field water balance in fertirrigated melon.

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    Agronomic management in Ciudad Real, a province in central Spain, is characteristic of semi-arid cropped areas whose water supplies have high nitrate (NO3?) content due to environmental degradation. This situation is aggravated by the existence of a restrictive subsurface layer of ?caliche? or hardpan at a depth of 0.60 m. Under these circumstances, fertirrigation rates, including nitrogen (N) fertilizer schedules, must be carefully calibrated to optimize melon yields while minimizing the N pollution and water supply. Such optimization was sought by fertilizing with different doses of N and irrigating at 100% of the ETc (crop evapotranspiration), adjusted for this crop and area. The N content in the four fertilizer doses used was: 0, 55, 82 and 109 kg N ha?1. Due to the NO3? content in the irrigation water, however, the actual N content was 30 kg ha?1 higher in all four treatments repeated in two different years. The results showed correlation between melon plant N uptake and drainage (Dr), which in turn affects the amount of N leached, as well as correlation between Dr and LAI (leaf area index) for each treatment. A fertilizer factor (?) was estimated through two methods, from difference in Dr and in LAI ratio with respect to the maximum N dose, to correct ETc based on N doses. The difference was found in the adjusted evapotranspiration in both years using the corresponding ? achieved 42?49 mm at vegetative period, depending on the method, and it was not significant at senescent period. Finally, a growth curve between N uptake and plant dry weight (DW) for each treatment was defined to confirm that the observed higher plant vigour, showing higher LAI and reduced Dr, was due mainly to higher N doses

    Reduction of computational times using the equivalent rectangle concept in the physics-based surface - subsurface models

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    The interaction between surface and subsurface domains in a basin can be studied using a physics-based model; however, the calibration and validation processes require a high computational effort due to their complex geometry. The authors propose an alternative to reduce the computational times during the calibration model by simplifying the geometry of the watershed that applies the equivalent rectangle concept. A quasi-3D equivalent rectangle is used to define the specific soil parameters of the Lerma river basin through sensitivity analysis that will later be applied in the calibration. The simplified model can highly accurately identify the parameter range for the initial values of the calibration process as well as if the reduction in running times is significant. Thus, the rectangle equivalent concept offers an alternative to speed-up the calibration of a 3-D fully-coupled surface sub-surface model.La interacción entre la superficie y subsuperficie de una cuenca se puede estudiar utilizando modelos físicos, pero debido a su compleja geometría los procesos de calibración y validación requieren altos tiempos computacionales. Para ello, se propone una alternativa que permita reducir los tiempos de calibración del modelo, mediante la simplificación de la geometría de la cuenca y empleando el concepto del rectángulo equivalente. El rectángulo equivalente es usado para definir los parámetros del suelo de la cuenca del río Lerma, a través de un análisis de sensibilidad, que posteriormente son empleados dentro de la calibración. El modelo simplificado identifica con una gran precisión los rangos y valores iniciales de los parámetros utilizados para los procesos de calibración y además reduce significativamente los tiempos computacionales. Por lo tanto, el concepto de rectángulo equivalente ofrece una alternativa para acelerar la calibración de modelos acoplados superficie-subsuperficie
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