3,616 research outputs found

    Wetland restoration and nitrate reduction: the example of the periurban wetland of Vitoria-Gasteiz (Basque Country, North Spain)

    Get PDF
    Changes in land use and agricultural intensification caused wetlands on the quaternary aquifer of Vitoria-Gasteiz (Basque Country) to disappear some years ago and nitrate concentration in groundwaters increased very quickly. The Basque Government recently declared the East Sector of this aquifer a Vulnerable Zone according to the 91/676/CEE European Directive. Recently, the wetlands have been restored through the closure of the main drainage ditches, the consequent elevation of the water table and the abondonment of agricultural practices near the wetlands. This is the case of the Zurbano wetland. Restoration has allowed the recovery of its biogeochemical function, which has reduced nitrate concentrations in waters. Nitrate concentrations which exceed 50 mg l–1 in groundwaters entering into the wetland are less than 10 mg l–1 at the outlet. Conditions in the wetland are conducive to the loss of nitrates: organic matter rich wetted soils, clay presence allowing a local semiconfined flow and very low hydraulic gradient. Water quality monitoring at several points around the wetland showed the processes involved in nitrate loss, although some aspects still remain unresolved. However, during storm events, the wetland effectively reduces the nitrate concentration entering the Alegria River, the most important river on the quaternary aquifer

    UNRAVELLING THE \u3ci\u3eREBOZO\u3c/i\u3e: THE EFFECTS OF POWER ON THE BODY IN SANDRA CISNEROS’S \u3ci\u3eCARAMELO\u3c/i\u3e

    Get PDF
    This thesis is a literary, cultural, and theoretical analysis of Sandra Cisneros’s novel Caramelo. Caramelo traces the coming-of-age of its young protagonist, Celaya. Through this character, Cisneros reveals the impact of living between cultures. Born of a Mexican immigrant father and a working-class Mexican American mother, Celaya finds herself asked to choose sides. Celaya’s grandmother, Soledad, is the central secondary character on whom all others react. She embodies the effects of colonialism on this family. Through Soledad’s struggles, readers come to see the psychological damage caused by power relationships that privilege part of the self over the whole. In combination with the other characters, readers see how all marginalized peoples share these traumas, giving Caramelo a universal reach. The work of Chicana critical theorists Gloria AnzaldĂșa, Emma PĂ©rez, Chela Sandoval, and EdĂ©n Torres illustrate the growth of Chicana Feminism in relation to the novel. They speak to how power relationships have evolved over time and how these relationships translate through the body depending on class, race, and gender. In this thesis, German philosopher Hegel also aids in tracing how Western perceptions of the body developed. Cisneros constructs Soledad as a victim of these perceptions and simultaneously chronicles how Celaya begins the process of breaking them apart. Through Celaya, Cisneros illustrates the many journeys an individual can take in examining and deconstructing power relationships and, thus, take vital steps towards healing

    A USB3.0 FPGA Event-based Filtering and Tracking Framework for Dynamic Vision Sensors

    Get PDF
    Dynamic vision sensors (DVS) are frame-free sensors with an asynchronous variable-rate output that is ideal for hard real-time dynamic vision applications under power and latency constraints. Post-processing of the digital sensor output can reduce sensor noise, extract low level features, and track objects using simple algorithms that have previously been implemented in software. In this paper we present an FPGA-based framework for event-based processing that allows uncorrelated-event noise removal and real-time tracking of multiple objects, with dynamic capabilities to adapt itself to fast or slow and large or small objects. This framework uses a new hardware platform based on a Lattice FPGA which filters the sensor output and which then transmits the results through a super-speed Cypress FX3 USB microcontroller interface to a host computer. The packets of events and timestamps are transmitted to the host computer at rates of 10 Mega events per second. Experimental results are presented that demonstrate a low latency of 10us for tracking and computing the center of mass of a detected object.Ministerio de EconomĂ­a y Competitividad TEC2012-37868-C04-0

    Instabilities in Zakharov Equations for Laser Propagation in a Plasma

    Full text link
    F.Linares, G.Ponce, J-C.Saut have proved that a non-fully dispersive Zakharov system arising in the study of Laser-plasma interaction, is locally well posed in the whole space, for fields vanishing at infinity. Here we show that in the periodic case, seen as a model for fields non-vanishing at infinity, the system develops strong instabilities of Hadamard's type, implying that the Cauchy problem is strongly ill-posed

    Study of the one-dimensional off-lattice hot-monomer reaction model

    Full text link
    Hot monomers are particles having a transient mobility (a ballistic flight) prior to being definitely absorbed on a surface. After arriving at a surface, the excess energy coming from the kinetic energy in the gas phase is dissipated through degrees of freedom parallel to the surface plane. In this paper we study the hot monomer-monomer adsorption-reaction process on a continuum (off-lattice) one-dimensional space by means of Monte Carlo simulations. The system exhibits second-order irreversible phase transition between a reactive and saturated (absorbing) phases which belong to the directed percolation (DP) universality class. This result is interpreted by means of a coarse-grained Langevin description which allows as to extend the DP conjecture to transitions occurring in continuous media.Comment: 13 pages, 5 figures, final version to appear in J. Phys.

    Overcoming Language Dichotomies: Toward Effective Program Comprehension for Mobile App Development

    Full text link
    Mobile devices and platforms have become an established target for modern software developers due to performant hardware and a large and growing user base numbering in the billions. Despite their popularity, the software development process for mobile apps comes with a set of unique, domain-specific challenges rooted in program comprehension. Many of these challenges stem from developer difficulties in reasoning about different representations of a program, a phenomenon we define as a "language dichotomy". In this paper, we reflect upon the various language dichotomies that contribute to open problems in program comprehension and development for mobile apps. Furthermore, to help guide the research community towards effective solutions for these problems, we provide a roadmap of directions for future work.Comment: Invited Keynote Paper for the 26th IEEE/ACM International Conference on Program Comprehension (ICPC'18

    Spike-based VITE control with Dynamic Vision Sensor applied to an Arm Robot.

    Get PDF
    Spike-based motor control is very important in the field of robotics and also for the neuromorphic engineering community to bridge the gap between sensing / processing devices and motor control without losing the spike philosophy that enhances speed response and reduces power consumption. This paper shows an accurate neuro-inspired spike-based system composed of a DVS retina, a visual processing system that detects and tracks objects, and a SVITE motor control, where everything follows the spike-based philosophy. The control system is a spike version of the neuroinspired open loop VITE control algorithm implemented in a couple of FPGA boards: the first one runs the algorithm and the second one drives the motors with spikes. The robotic platform is a low cost arm with four degrees of freedom.Ministerio de Ciencia e InnovaciĂłn TEC2009-10639-C04-02/01Ministerio de EconomĂ­a y Competitividad TEC2012-37868-C04-02/0

    Estrada y el derecho pĂșblico de las provincias y territorios nacionales

    Get PDF
    Ningun
    • 

    corecore