A standardised method for measuring in situ denitrification in shallow aquifers: numerical validation and measurements in riparian wetlands

A tracer test to examine in situ denitrification in shallow groundwater by a piezometer with a packer system used bromide as a tracer of dilution and acetylene (10%) to block the denitrification process at the nitrous oxide stage. During the test, dissolved oxygen, nitrate (NO3-), bromide (Br-), nitrous oxide (N2O) and dissolved organic carbon (DOC) were measured. To calibrate the experimental method, comparison with numerical simulations of the groundwater transfer were carried out, taking into account the environmental characteristics. The method was tested by measurements undertaken in different environmental conditions (geology, land use and hydrology) in two riparian wetlands. Denitrification rates measured by this method ranged from 5.7 10-6 g N-NO3-L-1 h-1 to 1.97 10-3 g N-NO3-L-1 h-1 The method is applicable in shallow aquifers with a permeability from 10-2 to 10-4m s-1

Violation of area-law scaling for the entanglement entropy in spin 1/2 chains

Entanglement entropy obeys area law scaling for typical physical quantum systems. This may naively be argued to follow from locality of interactions. We show that this is not the case by constructing an explicit simple spin chain Hamiltonian with nearest neighbor interactions that presents an entanglement volume scaling law. This non-translational model is contrived to have couplings that force the accumulation of singlet bonds across the half chain. Our result is complementary to the known relation between non-translational invariant, nearest neighbor interacting Hamiltonians and QMA complete problems.Comment: 9 pages, 4 figure

Economía, arbitristmo y política en la Monarquía hispánica a fines del siglo XVI

Mediante la referencia a numerosos tratadistas de fines del siglo XVI y comienzos del siglo XVII, el autor expone la imposibilidad de realizar una aproximación diferenciada al pensamiento teológico, político o económico coetáneo. A partir de la muerte de Felipe II, con la clara conciencia de vivir un período de crisis, estos autore3 plantearán desde esa perpectiva plural las causas de las alteraciones en la Monarquía Hispánica y los remedios orientados a lograr la restauración, no el cambio, del orden y los valores sociales en declive.A partir de la referencia a nombrosos tractadistes de finals del segle XVI i inicis del segle XVII, I'autor exposa la impossibilitat de portar a teme una aproximació diferenciada sobre el pensament teologic, polític o economic coetani. Arran de la mort de Felip II, amb la clara consciencia de viure un període de crisi, aquests autors plantejaran des d'aquesta perspectiva plural les causes de les mutacions a la Monarquia Hisphica i els remeis orientats a assolir la restauració, no el canvi, de I'ordre i els valors socials en declivi.Fortea Perez uses the testimonies of many late 16th century and early 17th century authors to state the impossibility of a discerning approach to contemporaneous theological, political or economical ideas. From this plural standpoint and with a neat conscience of being in the middle of a critical period, after the death of Philip II, those authors uttered the causes of the alterations in the Spanish Monarchy as well as the counteractions needed to restore, not to change, social order and values now in recession

Simulation of many-qubit quantum computation with matrix product states

Matrix product states provide a natural entanglement basis to represent a quantum register and operate quantum gates on it. This scheme can be materialized to simulate a quantum adiabatic algorithm solving hard instances of a NP-Complete problem. Errors inherent to truncations of the exact action of interacting gates are controlled by the size of the matrices in the representation. The property of finding the right solution for an instance and the expected value of the energy are found to be remarkably robust against these errors. As a symbolic example, we simulate the algorithm solving a 100-qubit hard instance, that is, finding the correct product state out of ~ 10^30 possibilities. Accumulated statistics for up to 60 qubits point at a slow growth of the average minimum time to solve hard instances with highly-truncated simulations of adiabatic quantum evolution.Comment: 5 pages, 4 figures, final versio

Self-organization of ultrasound in viscous fluids

We report the theoretical and experimental demonstration of pattern formation in acoustics. The system is an acoustic resonator containing a viscous fluid. When the system is driven by an external periodic force, the ultrasonic field inside the cavity experiences different pattern-forming instabilities leading to the emergence of periodic structures. The system is also shown to possess bistable regimes, in which localized states of the ultrasonic field develop. The thermal nonlinearity in the viscous fluid, together with the far-from-equilibrium conditions, are is the responsible of the observed effects

Transition to Chaotic Phase Synchronization through Random Phase Jumps

Phase synchronization is shown to occur between opposite cells of a ring consisting of chaotic Lorenz oscillators coupled unidirectionally through driving. As the coupling strength is diminished, full phase synchronization cannot be achieved due to random generation of phase jumps. The brownian dynamics underlying this process is studied in terms of a stochastic diffusion model of a particle in a one-dimensional medium.Comment: Accepted for publication in IJBC, 10 pages, 5 jpg figure