284 research outputs found

    IMPACT OF THE CAP REFORM ON THE SPANISH AGRICULTURAL SECTOR

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    This paper analyses the impact of the 2003 CAP reform on Spanish agricultural sector in the context of the recent CAP Health Check and high food prices, using PROMAPA, a positive mathematical programming model for representative farms. The analysis compares the model results for base year 2002 to the findings for a scenario with the CAP reform measures in place, taking into account recent modifications. The effect of adopting a full decoupling scheme instead of the present partial decoupling is also studied. Brief descriptions are given of the PROMAPA model, the representative farm considered and the assumptions about both price variations and the policy measures simulated. The findings showed that the farming area for cereals grew substantially after abolition of the compulsory set-aside and that the impact of transition to full decoupling was scant, except in the sheep and rearing cattle sub-sectors, where it considerably steepened the already sizeable decline in livestock numbers induced by the partial decoupling scheme.CAP reform, CAP Health Check, Decoupling, Spanish agricultural sector., Agricultural and Food Policy, Q10, Q12, Q18,

    IDR/UPM facilities for liquid bridge experimentation on earth under microgravity conditions

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    Besides space laboratories for in-orbit experimentation, Earth based facilities for laboratory experimentation are of paramount importance for the enhancement on liquid bridge knowledge. In spite of the constraints imposed by simulated microgravity (which force to work either with very small size liquid bridges or by using the Plateau tank technique, amongst other techniques), the availability and accessibility of Earth facilities can circumvent in many cases the drawbacks associated with simulated microgravity conditions. To support theoretical and in orbit experimental studies on liquid bridges under reduced gravity conditions, several ground facilities were developed at IDR. In the following these ground facilities are briefly described, and main results obtained by using them are cited

    Minimum volume of long liquid bridges between noncoaxial, nonequal diameter circular disks under lateral acceleration

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    The stability limit of minimum volume and the breaking dynamics of liquid bridges between nonequal, noncoaxial, circular supporting disks subject to a lateral acceleration were experimentally analyzed by working with liquid bridges of very small dimensions. Experimental results are compared with asymptotic theoretical predictions, with the agreement between experimental results and asymptotic ones being satisfactor

    Inter-channel Granger Causality for Estimating EEG Phase Connectivity Patterns in Dyslexia

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    Methods like Electroencephalography (EEG) and magnetoencephalogram (MEG) record brain oscillations and provide an invaluable insight into healthy and pathological brain function. These signals are helpful to study and achieve an objective and early diagnosis of neural disorders as Developmental Dyslexia (DD). An atypical oscillatory sampling could cause the characteristic phonological difficulties of dyslexia at one or more temporal rates; in this sense, measuring the EEG signal can help to make an early diagnosis of DD. The LEEDUCA study conducted a series of EEG experiments on children listening to amplitude modulated (AM) noise with slow-rhythmic prosodic (0.5–1 Hz) to detect differences in perception of oscillatory ampling that could be associated with dyslexia. The evolution of each EEG channel has been studied in the frequency domain, obtaining the analytical phase using the Hilbert transform. Subsequently, the cause-effect relationships between channels in ach subject have been reflected thanks to Granger causality, obtaining matrices that reflect the interaction between the different parts of the brain. Hence, each subject was classified as belonging or not to the control group or the experimental group. For this purpose, two ensemble classification algorithms were compared, showing that both can reach acceptable classifying erformance in delta band with an accuracy up to 0.77, recall of 0.91 and AUC of 0.97 using Gradient Boosting classifier.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Density functional study of Aun_n (n=2-20) clusters: lowest-energy structures and electronic properties

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    We have investigated the lowest-energy structures and electronic properties of the Aun_n(n=2-20) clusters based on density functional theory (DFT) with local density approximation. The small Aun_n clusters adopt planar structures up to n=6. Tabular cage structures are preferred in the range of n=10-14 and a structural transition from tabular cage-like structure to compact near-spherical structure is found around n=15. The most stable configurations obtained for Au13_{13} and Au19_{19} clusters are amorphous instead of icosahedral or fcc-like, while the electronic density of states sensitively depend on the cluster geometry. Dramatic odd-even alternative behaviors are obtained in the relative stability, HOMO-LUMO gaps and ionization potentials of gold clusters. The size evolution of electronic properties is discussed and the theoretical ionization potentials of Aun_n clusters compare well with experiments.Comment: 6 pages, 7 figure

    Respuesta de hongos benéficos del suelo asociados a Lotus tenuis a la aplicación de glifosato

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    En los últimos años se está adoptando la práctica de promoción de Lotus tenuis a través de la aplicación de glifosato en pastizales de La Pampa Deprimida debido a su importante aporte en cantidad y calidad de forraje. Sin embargo, diversos estudios han demostrado que el uso de este herbicida puede ocasionar efectos no deseados en microorganismos benéficos del suelo. El objetivo de este trabajo fue evaluar el efecto de la aplicación de glifosato sobre los hongos micorrícicos arbusculares y hongos septados oscuros asociados a L. tenuis. En una pastura de L. tenuis se establecieron dos tratamientos: Lotus tenuis promovido y Lotus tenuis establecido. En el primer caso, la pastura se pulverizó en invierno (fines de agosto) con 3,5 l/ha de glifosato, mientras en el segundo tratamiento la pastura de L. tenuis no recibió la aplicación del herbicida. Los resultados demuestran que el número de esporas viables de hongos micorrícicos arbusculares fue un 52% menor, y el porcentaje de arbúsculos en plantas de L. tenuis un 40% menor, en el tratamiento Lotus tenuis promovido en relación con el tratamiento Lotus tenuis establecido. La colonización radical por hongos septados oscuros no fue afectada por la aplicación de glifosato. La pérdida de funcionalidad de la simbiosis micorrícica podría en el mediano plazo afectar no solo la producción de biomasa de L. tenuis, sino también la diversidad y productividad de todas las especies presentes en la comunidad vegetal. La información generada en este trabajo será de utilidad para rediseñar prácticas de manejo que permitan la producción de alimento con un uso sustentable de los recursos.In recent years, the Lotus tenuis promotion through glyphosate application has been adopted in Flooding Pampa grasslands, due to the important contribution in forage quantity and quality of this species. However, several studies have shown that the use of glyphosate can cause undesirable effects on beneficial soil microorganisms. The objective of this study was to evaluate the effect of glyphosate application on the arbuscular mycorrhizal fungi and dark septate endophytes associated to L. tenuis. Two treatments were applied in plots located in a L. tenuis pasture: promoted Lotus tenuis and established Lotus tenuis. In the first case, plots were sprayed in winter (late August) with 3.5 l/ha of glyphosate, while in the second treatment plots did not receive herbicide application. Our results demonstrated that the number of viable spores of arbuscular mycorrhizal fungi was 52% lower, and the percentage of arbuscules in L. tenuis plants was 40% lower in the Promoted Lotus tenuis treatment in relation to Established Lotus tenuis treatment. Root colonization by dark septate endophytes was not affected by glyphosate application. The loss of functionality of the mycorrhizal symbiosis might in the medium-term affect not only L. tenuis biomass production, but also the diversity and productivity of the complete plant community. The information generated in this study will be useful to redesign management practices that allow food production with a sustainable use of resources.EEA Cuenca del SaladoFil: Druille, Magdalena. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; ArgentinaFil: Acosta, A. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; ArgentinaFil: Acosta, G. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; ArgentinaFil: Rossi, J.L. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; ArgentinaFil: Golluscio, Rodolfo A. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; ArgentinaFil: Bailleres, Matias Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado. Agencia de Extensión Rural Chascomus; Argentin

    Detecting Microscopic Black Holes with Neutrino Telescopes

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    If spacetime has more than four dimensions, ultra-high energy cosmic rays may create microscopic black holes. Black holes created by cosmic neutrinos in the Earth will evaporate, and the resulting hadronic showers, muons, and taus may be detected in neutrino telescopes below the Earth's surface. We simulate such events in detail and consider black hole cross sections with and without an exponential suppression factor. We find observable rates in both cases: for conservative cosmogenic neutrino fluxes, several black hole events per year are observable at the IceCube detector; for fluxes at the Waxman-Bahcall bound, tens of events per year are possible. We also present zenith angle and energy distributions for all three channels. The ability of neutrino telescopes to differentiate hadrons, muons, and possibly taus, and to measure these distributions provides a unique opportunity to identify black holes, to experimentally constrain the form of black hole production cross sections, and to study Hawking evaporation.Comment: 20 pages, 9 figure

    Electron Exchange Coupling for Single Donor Solid-State Qubits

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    Inter-valley interference between degenerate conduction band minima has been shown to lead to oscillations in the exchange energy between neighbouring phosphorus donor electron states in silicon \cite{Koiller02,Koiller02A}. These same effects lead to an extreme sensitivity of the exchange energy on the relative orientation of the donor atoms, an issue of crucial importance in the construction silicon-based spin quantum computers. In this article we calculate the donor electron exchange coupling as a function of donor position incorporating the full Bloch structure of the Kohn-Luttinger electron wavefunctions. It is found that due to the rapidly oscillating nature of the terms they produce, the periodic part of the Bloch functions can be safely ignored in the Heitler-London integrals as was done by Koiller et. al. [Phys. Rev. Lett. 88,027903(2002),Phys. Rev. B. 66,115201(2002)], significantly reducing the complexity of calculations. We address issues of fabrication and calculate the expected exchange coupling between neighbouring donors that have been implanted into the silicon substrate using an 15keV ion beam in the so-called 'top down' fabrication scheme for a Kane solid-state quantum computer. In addition we calculate the exchange coupling as a function of the voltage bias on control gates used to manipulate the electron wavefunctions and implement quantum logic operations in the Kane proposal, and find that these gate biases can be used to both increase and decrease the magnitude of the exchange coupling between neighbouring donor electrons. The zero-bias results reconfirm those previously obtained by Koiller.Comment: 10 Pages, 8 Figures. To appear in Physical Review

    Probing Kaluza-Klein Dark Matter with Neutrino Telescopes

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    In models in which all of the Standard Model fields live in extra universal dimensions, the lightest Kaluza-Klein (KK) particle can be stable. Calculations of the one-loop radiative corrections to the masses of the KK modes suggest that the identity of the lightest KK particle (LKP) is mostly the first KK excitation of the hypercharge gauge boson. This LKP is a viable dark matter candidate with an ideal present-day relic abundance if its mass is moderately large, between 600 to 1200 GeV. Such weakly interacting dark matter particles are expected to become gravitationally trapped in large bodies, such as the Sun, and annihilate into neutrinos or other particles that decay into neutrinos. We calculate the annihilation rate, neutrino flux and the resulting event rate in present and future neutrino telescopes. The relatively large mass implies that the neutrino energy spectrum is expected to be well above the energy threshold of AMANDA and IceCube. We find that the event rate in IceCube is between a few to tens of events per year.Comment: 13 pages, 3 figures, LaTeX; typos fixed, version to appear in PR
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