104 research outputs found

    Reiteraciones: ritmo y diseminación en Génesis 1,1-2,4a

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     PRELIMINARES. I. LA SECCIÓN CENTRAL. 1. La disposición rítmica de Génesis 1,3-31. 1.1. Ritmo. 1.2. Diseminación. 2. Una hipótesis sobre el procedimiento de construcción de Génesis 1,3-31. 3. El sentido de la presencia de los elementos rítmicos y de los diseminados. 3.1. La presencia de los días. 3.2. La presencia de las acciones. 3.2.1. Las seis acciones centrales. 3.2.2. Las dos acciones marginales. 3.3. La estructura de cada acción creadora. 3.3.1. «Y dijo Dios». 3.3.2. «Y fue así». 3.3.3. Las operaciones con las que Dios crea. 3.3.4. «Y llamó». «Y vio». 4. Progresión temática. II. LAS SECCIONES MARGINALES. CONCLUSIONES

    Formación en Cinemática y Dinámica de Sistemas Multicuerpo Mediante Coordenadas Naturales

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    La formación de los futuros ingenieros mecánicos en dinámica de sistemas multicuerpo 3-D rara vez encuentra una materia específica en los planes de estudio, ni siquiera en postgrado. Cuando sólo se dispone de algunas horas (entre 5 y 10 horas de clase y unas 15 de trabajo personal) en el marco de una materia más general, las coordenadas naturales y Matlab son probablemente el único camino para alcanzar ciertos objetivos prácticos. Aquí se aborda cómo se pueden alcanzar estos objetivos, con un aprendizaje basado en .casos reales. Very often, the curriculum of mechanical engineers doesn't include any specific subject on kinematics and dynamics of multibody systems. In these situations the unique opportunity to introduce MBS is to dedicate from 5 to 10 hours to this subject inside a more general course, plus about 15 hours of personal work. This paper shows how this short time can be enough if natural coordinates are used. Keywords

    Large Scale dynamics of Brown trout populations across Navarra Rivers (North Spain)

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    Most studies on the population dynamics of stream-living salmonids have attempted to elucidate the causes of variation in demographic traits or population abundance by analyzing population time series vis-á-vis environmental data. In order to express the results on a scale compatible with fishery management strategies, most studies have been done at the scale of a stream reach, a stream or a river basin with few studies focused on the population dynamics at larger geographic scales. Our goal is to determine the extent to which the effects of both, exogenous and endogenous factors actually describe the variations in abundance of brown trout populations inhabiting separated river basins across a large and environmentally heterogeneous territory. We tested whether the trout abundance across a large territory involving distinct populations could be described by determining the extent to which exogenous and endogenous drivers underlie the per capita population growth rate estimated from long-term time series in a way similar to that previously assessed at smaller geographical scales. We have developed a simple multivariate linear model that synthetically combines an index of large-scale climate variation with mean population abundance. This model has been built on the basis of a data set encompassing 18-year quantifications of abundance at 68 sampling stations. The results of our simulation model predict mean trout abundance with less than 10% error

    Assessment of sustainable land management practices in Mediterranean rural regions

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    Sustainable land management practices can be suitable vehicles to simultaneously address the causes and consequences of land degradation, desertification, and climate change in land managed systems. Here, we assess the potential of a variety of sustainable land management practices that, beyond addressing specific and local issues, assist in tackling Mediterranean Basin-wide land-use challenges. With this work, we aim to highlight those options that simultaneously promote local and regional Basin-wide adaptation. To do that, we developed a novel multi-objective assessment that evaluates the effectiveness of 104 practices adopted within the Mediterranean Basin and documented in the World Overview of Conservation Approaches and Technologies global database. Results indicate that agroforestry and green covers in perennial woody crops can promote multiple ecosystem services while addressing climate change adaptation. We further argue that these two practices together with reforestation, assist in regulating the hydrological cycle of the Basin and in maintaining its multifunctional landscape. Lastly, we reflect on potential biophysical and socio-economic barriers and opportunities associated with the implementation of the three practices. Our approach provides a Basin-wide integrated view that facilitates the coordination of sustainable management strategies across the Mediterranean region. © 2020 Elsevier LtdThe authors would like to thank two anonymous reviewers whose comments helped improve this work. This research is supported by the Basque Government through the BERC 2018–2021 program and by the Spanish Ministry of Economy and Competitiveness MINECO through BC3 María de Maeztu excellence accreditation MDM 2017–0714. M. Almagro acknowledges financial support from the Juan de la Cierva Program (IJCI-2015-23500)

    Treatment of congenital atypical haemangiosarcoma in a foal

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    Haemangiosarcoma is a rare vascular tumour in horses, usually originating from blood vessel endothelial cells. We present the case of an 8-day-old foal, referred for an atypical large subcutaneous mass on the left side since birth. Ultrasonographically, it showed multiple cavities with hypoechoic content, marked vascularisation and fluid movement between cavities. As the nature of the mass suggested that surgery could result in profuse bleeding, we decided to perform an initial arteriography to identify the pattern and calibre of the main vessels and embolisation of this vascular supply, which allowed surgical removal with less bleeding than expected. This approach, with pre-surgical transarterial embolisation of the tumour, is not commonly used in equine surgery. Histology established a diagnosis of cutaneous haemangiosarcoma. During 1-year post-surgery, clinical and ultrasound examinations were carried out without any signs of recurrence or metastasis. One year later, the foal was euthanised due to a limb fracture. No macroscopic signs of metastasis were observed at necropsy. Histology showed no signs of recurrence. Cutaneous haemangiosarcomas, though rare, should be included in the differential of masses and growths with compatible ultrasound or cytological findings. Transcatheter arterial embolisation of highly vascularised neoplasms can reduce bleeding and facilitate subsequent surgical resection

    Modelling and valuing the environmental impacts of arable, forestry and agroforestry systems: a case study

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    The use of land for intensive arable production in Europe is associated with a range of externalities that typically impose costs on third parties. The introduction of trees in arable systems can potentially be used to reduce these costs. This paper assesses the profitability and environmental externalities of a silvoarable agroforestry system, and compares this with the profitability and environmental externalities from an arable system and a forestry system. A silvoarable experimental plot of poplar trees planted in 1992 in Bedfordshire, Eastern England, was used as a case study. The Yield-SAFE model was used to simulate the growth and yields of the silvoarable, arable, and forestry land uses along with the associated environmental externalities, including carbon sequestration, greenhouse gas emissions, nitrogen and phosphorus surplus, and soil erosion losses by water. The Farm-SAFE model was then used to quantify the monetary value of these effects. The study assesses both the financial profitability from a farmer perspective and the economic benefit from a societal perspective. The arable option was the most financially profitable system followed by the silvoarable system and forestry. However, when the environmental externalities were included, silvoarable agroforestry provided the greatest benefit. This suggests that the appropriate integration of trees in arable land can provide greater well-being benefits to society overall, than arable farming without trees, or forestry systems on their own

    Simulation model for the study of overhead rail current collector systems dynamics, focused on the design of a new conductor rail

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    Overhead rigid conductor arrangements for current collection for railway traction have some advantages compared to other, more conventional, energy supply systems. They are simple, robust and easily maintained, not to mention their flexibility as to the required height for installation, which makes them particularly suitable for use in subway infrastructures. Nevertheless, due to the increasing speeds of new vehicles running on modern subway lines, a more efficient design is required for this kind of system. In this paper, the authors present a dynamic analysis of overhead conductor rail systems focused on the design of a new conductor profile with a dynamic behaviour superior to that of the system currently in use. This means that either an increase in running speed can be attained, which at present does not exceed 110 km/h, or an increase in the distance between the rigid catenary supports with the ensuing saving in installation costs. This study has been carried out using simulation techniques. The ANSYS programme has been used for the finite element modelling and the SIMPACK programme for the elastic multibody systems analysis

    Dry deposition of air pollutants on trees at regional scale: A case study in the Basque Country

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    There is increased interest in the role of trees to reduce air pollution and thereby improve human health and well-being. This study determined the removal of air pollutants by dry deposition of trees across the Basque Country and estimated its annual economic value. A model that calculates the hourly dry deposition of NO2, O3, SO2, CO and PM10 on trees at a 1 km x 1 km resolution at a regional scale was developed. The calculated mean annual rates of removal of air pollution across various land uses were 12.9 kg O3 ha-1, 12.7 kg PM10 ha-1, 3.0 kg NO2 ha-1, 0.8 kg SO2 ha-1 and 0.2 kg CO ha-1. The results were then categorised according to land use in order to determine how much each land use category contributed to reducing air pollution and to determine to what extent trees provided pollution reduction benefits to society. Despite not being located in the areas of highest pollutions, coniferous forests, which cover 25% of the land, were calculated to absorb 21% of the air pollution. Compared to other land uses, coniferous forests were particularly effective in removing air pollution because of their high tree cover density and the duration of leaf life-span. The total economic value provided by the trees in reducing these pollutants in terms of health benefits was estimated to be 60 million yr-1 which represented around 0.09% of the Gross Domestic Product of the Basque Country in 2016. Whilst most health impacts from air pollution are in urban areas the results indicate that most air pollution is removed in rural areas. © 2019 Elsevier B.V.Silvestre García de Jalón, Jorge Curiel Yuste and Aline Chiabai acknowledge support from the Basque Government through the BERC 2018-2021 program and from the Spanish Ministry of Science, Innovation and Universities through the BC3 María de Maeztu excellence accreditation ( MDM-2017-0714

    Assessing the impact of greenhouse gas emissions on economic profitability of arable, forestry, and silvoarable systems

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    This study assesses the greenhouse gas (GHG) emissions and sequestration of a silvoarable system with poplar trees and a crop rotation of wheat, barley, and oilseed rape and compares this with a rotation of the same arable crops and a poplar plantation. The Farm-SAFE model, a financial model of arable, forestry, and silvoarable systems, was modified to account for life-cycle greenhouse gas emissions. Greenhouse gas emissions from tree and crop management were determined from life-cycle inventories and carbon storage benefits from the Yield-SAFE model, which predicts crop and tree yields in arable, forestry, and silvoarable systems. An experimental site in Silsoe in southern England served as a case study. The results showed that the arable system was the most financially profitable system, followed by the silvoarable and then the forestry systems, with equivalent annual values of EUR 560, 450 and 140 ha−1, respectively. When the positive and negative externalities of GHG sequestration and emissions were converted into carbon equivalents and given an economic value, the profitability of the arable systems was altered relative to the forestry and silvoarable systems, although in the analysis, the exact impact depended on the value given to GHG emissions. Market values for carbon resulted in the arable system remaining the most profitable system, albeit at a reduced level. Time series values for carbon proposed by the UK government resulted in forestry being the most profitable system. Hence, the relative benefit of the three systems was highly sensitive to the value that carbon was given in the analysis. This in turn is dependent on the perspective that is given to the analysis
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