864 resultados para terrestrial turtles
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Compost, vermicompost and biochar amendments are thought to improve soil quality and plant yield. However, little is known about their long-term impact on crop yield and the environment in tropical agro-ecosystems. In this study we investigated the effect of organic amendments (buffalo manure, compost and verrnicompost) and biochar (applied alone or with vermicompost) on plant yield, soil fertility, soil erosion and water dynamics in a degraded Acrisol in Vietnam. Maize growth and yield, as well as weed growth, were examined for three years in terrestrial mesocosms under natural rainfall. Maize yield and growth showed high inter-annual variability depending on the organic amendment. Vermicompost improved maize growth and yield but its effect was rather small and was only significant when water availability was limited (year 2). This suggests that vermicompost could be a promising substrate for improving the resistance of agrosystems to water stress. When the vermicompost biochar mixture was applied, further growth and yield improvements were recorded in some cases. When applied alone, biochar had a positive influence on maize yield and growth, thus confirming its interest for improving long-term soil productivity. All organic amendments reduced water runoff, soil detachment and NH4+ and NO3- transfer to water. These effects were more significant with vermicompost than with buffalo manure and compost, highlighting that the beneficial influence of vermicompost is not limited to its influence on plant yield. In addition, this study showed for the first time that the combination of vermicompost and biochar may not only improve plant productivity but also reduce the negative impact of agriculture on water quality. (C) 2015 Elsevier B.V. All rights reserved.
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Electromagnetic field produced by a lightning strike to ground causes significant induction to tall objects in the vicinity. The frequency of occurrence of such nearby ground strikes can be higher than the number of direct strikes. Therefore, a complete knowledge on these induced currents is of practical relevance. However, limited efforts towards the characterisation of such induced currents in tall down-conductors could be seen in the literature. Due to the intensification of the background field caused by the descending stepped leader, tall towers/down-conductors can launch upward leaders of significant length. The nonlinearity in the conductance of upward leader and the surrounding corona sheath can alter the characteristics of the induced currents. Preliminary aspects of this phenomenon have been studied by the author previously and the present work aims to perform a detailed investigation on the role of upward leaders in modifying the characteristics of the induced currents. A consistent model for the upward leader, which covers all the essential electrical aspects of the phenomena, is employed. A first order arc model for representing the conductance of upward leader and a field dependant quadratic conductivity model for the corona sheath is employed. The initial gradient in the upward leader and the field produced by the return stroke forms the excitation. The dynamic electromagnetic response is determined by solving the wave equation using thin-wire time-domain formulation. Simulations are carried out initially to ascertain the role of individual parameters, including the length of the upward leader. Based on the simulation results, it is shown that the upward leader enhances the induced current, and when significant in length, can alter the waveshape of induced current from bipolar oscillatory to unipolar. The duration of the induced current is governed by the length of upward leader, which in turn is dependant on the return stroke current and the effective length of the down-conductor. If the current during the upward leader developmental phase is considered along with that after the stroke termination to ground, it would present a bipolar current pulse. (C) 2015 Elsevier Ltd. All rights reserved.
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Experiments were performed, in a terrestrial environment, to study the migration and interaction of two drops with different diameters in matrix liquid under temperature gradient field. Pure soybean oil and silicon oil were used as matrix liquid and the drop liquid, respectively. The information on the motions of two drops was recorded by CCD camera system in the experiments to analyze the trajectories and velocities of the drops. Our experiments showed that, upon two drops approaching each other, the influence of the larger drop on the motion of the smaller one became significant. Meanwhile the smaller drop had a little influence on the larger one all the time. The oscillation of migration velocities of both drops was observed as they were approaching. For a short period the smaller drop even moved backward when it became side by side with the larger one during the migration. Although our experimental results on the behavior of two drops are basically consistent with the theoretical predictions, there are also apparent differences. 2006 Elsevier Ltd. All rights reserved. Keywords: Thermocapillary migration; Drop; Interaction; Oscillation 1. Introduction A bubble or drop will move when placed in another fluid with temperature gradient. This motion happens as a consequence of the variation of interfacial tension with temperature. Such a phenomenon is already known as Marangoni migration problem. With the development of microgravity science, bubble dynamics and droplet dynamics became a hot point problem of research because this investigation is very important for basic research as well as for applications in reduced gravity environment, such as space material science, chemical engineering and so on. Young et al. first investigated the thermocapillary migration of
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Abstract: The idea of a “paradise in politics” is an answer to the cosmogonic- anthropogonic problem that, through their bodies, the life of human beings has been shaped politically from the very beginning: all creation is a creation of bodies and bodies are power. All creation, furthermore, means separation, it emerges through a multiplicity of things and beings only. The conventional solution for the problem, in the realm of human beings, consists in forming societies out of a multiplicity of indivuals that remains as such. The solution of a “paradise in politics”, however, envisions a “healing” of creation through a bodily transmutation by which a world of bodies emerges that is freed from the problem of bodies: separation, power. The article discusses the negative cosmology with which all tales on a paradise in politics start. It shows the essential role of phantasy in the constitution of these tales, and elucidates the principal structural elements through which visions of a paradise in politics are built. A special attention is given to the parallelism between these visions and known religious thought, as in the case of the concepts of apokatastasis or perichoresis, for instance. Methodically, the article achieves a demonstration of its subject by an extensive presentation and analysis of two case studies: Rousseau’s vision of a “terrestrial paradise” and the attempt at “bodily redemption” put on the stage in 1968-69 by the “Living Theatre” Group with its performance “Paradise Now”.
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The use of sustainability indicators for evaluating sanitation systems is applied to the Erdos Eco- Town Project (EETP) in China for illustration. The EETP is the largest urban settlement in the world employing ecological sanitation, which incorporates separation of waste streams, dry toilets, and resource recovery. The EETP’s dry sanitation system is compared against the Dongsheng District’s conventional sewer and centralised STP. The two systems are compared based on technological, environmental, economic, and societal indicators. Overall, the two systems perform reasonably well from a technological perspective. The conventional system performs significantly better than the dry system with regards to land and energy requirements, and global warming potential; it also performs better based on freshwater aquatic and terrestrial ecotoxicity potentials, but by a smaller margin. The dry system has superior environmental performance based on water consumption, eutrophication potential, and nutrient and organic matter recovery. The dry system is a more costly system as it requires greater infrastructure and higher operational costs, and does not benefit from economies of scale. The waterborne system performs better based on the societal indicators largely because it is a well-established system.
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Resumen: Dado que la imaginación medieval del mundo se nutre de ideas directamente heredadas de la Biblia, a menudo en contienda con la exploración empírica del globo terrestre, el estudio de los relatos de viajes en general, y de las guías de peregrinos a Tierra Santa en particular, nos permite comprender el modo en que el hombre de letras medieval se apropiaba del imaginario bíblico para darle forma a un mundo cuyos límites exóticos cobraban familiaridad por ser el escenario de las historias más apreciadas por los lectores de la época. Dentro del repertorio de literatura de viajes hispánica, La fazienda de Ultramar, cuya redacción se habría llevado a cabo a comienzos del siglo XIII, es un texto de singular importancia, por ser una de las más antiguas versiones en romance de la Biblia. No solo es un texto fundacional para una tradición que cambió la forma en que el hombre medieval se acercaba a las Sagradas Escrituras, sino que, debido a su carácter de itinerarium, nos permite conocer el modo en que la Biblia afectaba la imaginación del lector medieval acerca de la geografía de Tierra Santa. Es por ello que el propósito de esta comunicación será analizar el modo en que la estructura de itinerarium incide sobre el tratamiento del texto sagrado y la forma en que la lógica narrativa de los episodios bíblicos se subordina a la geográfica. De esta forma, se intentará echar luz sobre algunas cuestiones que han limitado el estudio de esta obra.
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1 PDF document (8 pp., English).-- Contributed to: VSMM'08: 14th International Conference on Virtual Systems and Multimedia (Limassol, Cyprus, Oct 20-25, 2008)
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On 17-20 July 2007, 45 experts on sea turtles, fisheries, conservation and finance from 10 countries convened at the Bellagio Sea Turtle Conservation Initiative workshop in Terengganu to focus on methods to save the imperiled Pacific leatherback from extinction. The group developed a strategic plan to guide the prioritization and long term financing of Pacific leatherback turtle conservation and recovery objectives. Participants identified critical conservation actions and agreed that a business plan is urgently needed to reverse the trajectory towards extinction of the Pacific leatherback. The conservation actions prioritized by the participants encompassed protecting nesting beaches including eggs and nesting females; reducing direct and indirect turtle take in coastal fisheries; and strengthening regional and sub-regional cooperation. The group committed to work together on fundraising and implementation of these urgent conservation actions. This report presents outputs and the plan that was produced from the workshop.
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The effects of potential sea level rise on the shoreline and shore environment have been briefly examined by considering the interactions between sea level rise and relevant coastal processes. These interactions have been reviewed beginning with a discussion of the need to reanalyze previous estimates of eustatic sea level rise and compaction effects in water level measurement. This is followed by considerations on sea level effects on coastal and estuarine tidal ranges, storm surge and water level response, and interaction with natural and constructed shoreline features. The desirability to reevaluate the well known Bruun Rule for estimating shoreline recession has been noted. The mechanics of ground and surface water intrusion with reference to sea level rise are then reviewed. This is followed by sedimentary processes in the estuaries including wetland response. Finally comments are included on some probable effects of sea level rise on coastal ecosystems. These interactions are complex and lead to shoreline evolution (under a sea level rise) which is highly site-specific. Models which determine shoreline change on the basis of inundation of terrestrial topography without considering relevant coastal processes are likely to lead to erroneous shoreline scenarios, particularly where the shoreline is composed of erodible sedimentary material. With some exceptions, present day knowledge of shoreline response to hydrodynamic forcing is inadequate for long-term quantitative predictions. A series of interrelated basic and applied research issues must be addressed in the coming decades to determine shoreline response to sea level change with an acceptable degree of confidence. (PDF contains 189 pages.)
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[ES] Este proyecto contiene información obtenida en el siguiente trabajo de documentación geométrica de un elemento patrimonial:
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对海北高寒草甸地区水热传输过程进行了系统观测,特别考虑了叶片气孔为非饱和水汽条件下的交换情况,结合修正的根系吸水公式,发展了一个多层陆气耦合模式.利用该模式对中国科学院海北高寒草甸生态试验站地区矮嵩草草甸陆气水热交换进行了数值模拟,分析了湍流交换的物理过程,给出了沿高度分布的各物理量.模拟结果与实测值吻合较好.
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The Hawkesbury-Nepean River in New South Wales (NSW), Australia, is the largest river system in the Sydney metropolitan area, and it drains most of the developing areas to the west. This catchment is under increasing pressure from urban expansion and the river frequently experiences extended periods of low flows due to a combination of extensive river regulation and the Australian temperate climate. Added to this, the river and several of its tributaries receive treated sewage and stormwater from various sources. Habitats and biota within the Hawkesbury-Nepean River catchment have been altered since European settlement and many introduced species have spread throughout the terrestrial and aquatic environment (Recher et al. 1993). Submersed macrophyte assemblages within the river have undergone significant changes in their distribution and abundance due to eutrophication, habitat alteration and changes to river flows (Recher et al 1993). Anecdotal evidence and some early unpublished studies suggest that egeria (Egeria densa Planchon), introduced from South America as an aquarium plant, was present in the Hawkesbury-Nepean River prior to 1980. Sainty (1973) reported a persistent and troublesome infestation over a number of years at Wallacia in the upper Nepean River. Here, as part of a larger study on the ecology of macrophyte and invertebrate assemblages associated with anthropogenic disturbance in the Hawkesbury-Nepean River, we document the rapid spread of egeria since 1994. Significant increases in egeria biomass were also found, and we present preliminary evidence which suggest that the native ribbonweed, vallisneria (Vallisneria americana Michx.) is being displaced.
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Mechanical weed harvesting has been used to control nuisance vegetation in Lake Keesus since 1979. Fish, turtles, and amphibians often become entangled in the vegetation and are incidentally removed from the lake while harvesting weeds. Mechanical harvesting removed 2 to 8% of the standing crop of juvenile fish in harvested areas in Saratoga Lake, New York (Mikol 1985) and 32% of the fish population in harvested areas in Orange Lake, Florida, representing an estimated replacement value of $6000 per ha (Haller et al. 19890). Engle (1990) found mechanical harvesting removed 21,000 to 31,000 fish per year from Lake Halverson, Wisconsin, representing 25% of the fry in the lake. Little other current information has been published concerning aquatic vertebrate removal by mechanical weed harvesting in Wisconsin, though it is a commonly used management tool. Additionally, only Engle (1990) reported information on the removal of turtles relative to weed harvesting, but none on amphibians. The objective of this study was to document the number, species, and size of vertebrates removed by mechanically harvesting weeds in Lake Keesus.
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[ES] Existe una continuación de este trabajo realizada en 2014, cuyo título es: