Progresos en el conocimiento de la sostenibilidad económica, social y ambiental del desarrollo sostenible en los espacios rurales iberoamericanos

El trabajo conjunto desde el año 2003 entre la Universidad de Almería y varias Universidades Iberoamericanas, ha permitido conformar una Red Iberoamericana de Investigación sobre Desarrollo en Espacios Rurales. Esta red de carácter multidisplinar lleva a cabo investigaciones en distintos espacios rurales de Iberoamérica, en torno al desarrollo sostenible de los espacios rurales Iberoamericanos. En este artículo se recogen los principales resultados y conclusiones que se han obtenido en los estudios realizados, y se ponen de manifiesto los progresos en el conocimiento de la sostenibilidad de los recursos naturales, de los sistemas productivos agrícolas, de la diversificación de las actividades económicas, y de aspectos sociales como el trabajo decente y género. Además, se analiza la incorporación de las nuevas tecnologías en el medio rural y su uso en la enseñanza del desarrollo rural sostenible en la educación superior

Conclusiones sobre investigaciones y experiencias de desarrollo sostenible en espacios rurales iberoamericanos

En junio de 2009 se celebró en Almería el “III Seminario Internacional de Cooperación y Desarrollo en Espacios Rurales Iberoamericanos. Sostenibilidad e Indicadores”, insertado en tres Proyectos vivos de la Universidad de Almería junto con once Universidades Iberoamericanas, en el marco del Programa InterUniversitario (PCI-2008) financiado por la AECID. Este evento contó con la participación de profesionales que presentaron los avances y resultados de sus investigaciones y experiencias ligadas a la consecución de nuevos instrumentos que permitan alcanzar la sostenibilidad en los espacios rurales. Además, con el evento se consolidó la Red de trabajo existente, se fomentó el trabajo participativo junto a los grupos locales de desarrollo, y se promovió la implementación de las TICs en la construcción de Sistemas de Indicadores. Las conclusiones del Seminario, y las aportaciones realizadas por los investigadores en el desarrollo del mismo, se presentan por áreas temáticas

Self-healing of dense asphalt concrete by two different approaches: electromagnetic induction and infrared radiation

Self-healing of cracks in asphalt mixtures is a phenomenon that can be accelerated by reducing the viscosity of bitumen as it increases the capillarity flow through the cracks. One method to achieve this is by increasing temperature, which also produces a thermal expansion that contributes to the circulation of the bitumen through cracks. In the present paper, the healing performance of asphalt mixture heated using infrared heating to simulate the natural solar radiation, and induction heating, a new method to increase the temperature of asphalt pavements, were compared in terms of time and healing temperature. Healing was defined as the relationship between the 3-point bending strength of an asphalt beam before and after healing. The results show that both methods reach similar and satisfactory healing ratios at around 90 %. However, induction heating is more energy efficient because the effect is concentrated on the binder, instead of heating the whole mix. This can be translated into much shorter heating times to reach the same healing level. Finally, an optimum radiation energy was found, after which higher amounts of infrared radiation damage the properties of the healed material

Quantum recoil effects in finite-time disentanglement of two distinguishable atoms

Starting from the requirement of distinguishability of two atoms by their positions, it is shown that photon recoil has a strong influence on finite-time disentanglement and in some cases prevents its appearance. At near-field inter atomic distances well localized atoms, with maximally one atom being initially excited, may suffer disentanglement at a single finite time or even at a series of equidistant finite times, depending on their mean inter atomic distance and their initial electronic preparation.Comment: 13 pages, 1 figure, submitted to Physical Review on august 2

Efectos del tráfico del tractor sobre la distribución de la compactación del suelo y los rendimientos de trigo en España

395-403The general objective of this paper was to quantify the changes in the physical properties of an Aridisol soil and the effect on wheat yield due to agricultural tractors traffic in the Vélez Blanco District, Almería Spain. Parameters measured were cone index (CI) in the 0-600 mm depth profile, bulk density (BD) and rut depth; the variable wheat yields (WY) was measured too. The traffic treatments applied were: 0 (control plot), 1, 3, 5, and 7 tractor passes in the same tracks. Each experimental plot was trafficked with two tractors, one light (60 kN) and one heavy (80 kN). In topsoil (0-200 mm), up to five passes of the heavy (HT) and light tractors (LT), as in one and three passes, the BD and CI values responded to the ground pressure being higher in absolute value for LT. For the 200 to 400 mm depth range HT caused higher CI (1,570 to 2,200 kPa) and BD (1.38 to 1.68 Mg m-3) values than LT. Eight months later, WY was evaluated in tractor's track areas and decreases in the range of 18-38 percent, were measured. For seven passes the applications of total loads of 80 and 60 kN increased BD up to 1.5 Mg m-3 at depths of 200-600 mm. Although soil had high bulk density prior to traffic treatments, a significant increment of subsoil compaction still occurred due to the high traffic intensities applied

Origin of Small Barriers in Jahn–Teller Systems:Quantifying the Role of 3d–4s Hybridization in the Model System NaCl:Ni⁺

Despite its relevance, the microscopic origin of the energy barrier, B, between the compressed and elongated geometries of Jahn–Teller (JT) systems is not well understood yet because of a lack of quantitative data about its various contributions. Seeking to clear up this matter, we have carried out both periodic and cluster ab initio calculations on the model system NaCl:Ni+. This system is particularly puzzling because, according to experimental data, its barrier is much smaller than that for other d9 and d7 ions in similar lattices. All calculations performed on the model system lead, in fact, to values |B| ≤ 160 cm–1, which are certainly smaller than B = 500 cm–1 derived for NaCl:M2+ (M = Ag, Rh) or B = 1024 cm–1 obtained for KCl:Ag2+. As a salient feature, analysis of calculations carried out as a function of the Qθ (3z2 – r2) coordinate unveils the microscopic origin of the barrier. It is quantitatively proven that the elongated geometry observed for NaCl:Ni+ is due to the 3d–4s vibronic admixture, which is slightly larger than the anharmonicity in the eg JT mode that favors a compressed geometry. The existence of these two competing mechanisms explains the low value of B for the model system, contrary to cases where the complex formed by d9 or d7 ions is elastically decoupled from the host lattice. Although the magnitude of B for NaCl:Ni+ is particularly small, the tunneling splitting, 3Γ, is estimated to be below 9 cm–1, thus explaining why the coherence is easily destroyed by random strains and thus a static JT effect is observed experimentally. As a main conclusion, the barrier in JT systems cannot be understood neglecting the tiny changes of the electronic density involved in small distortions. The present calculations reasonably explain the experimental g tensor of NaCl:Ni+, pointing out that the d–d transitions in NiCl65– are much smaller than those for CuCl64– and the optical electronegativity of Ni+ is only around 1.</p

Efectos del tráfico del tractor sobre la distribución de la compactación del suelo y los rendimientos de trigo en España

The general objective of this paper was to quantify the changes in the physical properties of an Aridisol soil and the effect on wheat yield due to agricultural tractors traffic in the Vélez Blanco District, Almería Spain. Parameters measured were cone index (CI) in the 0-600 mm depth profile, bulk density (BD) and rut depth; the variable wheat yields (WY) was measured too. The traffic treatments applied were: 0 (control plot), 1, 3, 5, and 7 tractor passes in the same tracks. Each experimental plot was trafficked with two tractors, one light (60 kN) and one heavy (80 kN). In topsoil (0-200 mm), up to five passes of the heavy (HT) and light tractors (LT), as in one and three passes, the BD and CI values responded to the ground pressure being higher in absolute value for LT. For the 200 to 400 mm depth range HT caused higher CI (1,570 to 2,200 kPa) and BD (1.38 to 1.68 Mg m-3) values than LT. Eight months later, WY was evaluated in tractor's track areas and decreases in the range of 18-38%, were measured. For seven passes the applications of total loads of 80 and 60 kN increased BD up to 1.5 Mg m-3 at depths of 200-600 mm. Although soil had high bulk density prior to traffic treatments, a significant increment of subsoil compaction still occurred due to the high traffic intensities applied.El objetivo general del estudio fue cuantificar los cambios producidos en las propiedades físicas de un suelo Aridisol y los efectos sobre el rendimiento del trigo debido al tráfico de tractores agrícolas en Vélez Blanco, Almería, España. Los parámetros analizados fueron índice de cono (IC) a una profundidad de 0-600 mm, densidad aparente (DA) y profundidad de huella; también se analizó la variable rendimiento del trigo (RT). Los tratamientos de tráfico aplicados fueron: cero (parcela testigo), y uno, tres, cinco, y siete pasadas de tractor sobre la misma huella. En cada parcela experimental se utilizaron dos tractores, uno ligero (60 kN) y uno pesado (80 kN). En el horizonte superficial (0-200 mm), hasta las cinco pasadas de los tractores pesados (TP) y ligeros (TL), los valores de DA y de IC respondieron a la presión en el área de contacto, siendo más alto en valor absoluto para TL cuando pasó una y tres veces. Para el rango de profundidad 200-400 mm, TP causó valores más altos de IC (1.570 a 2.200 kPa) y DA (1,38 a 1,68 Mg m-3) que TL. RT se evaluó ocho meses después sobre el área pisada, observándose una disminución en un rango de 18-38%. Las cargas totales aplicadas de 80 y 60 kN, con siete pasadas, aumentaron DA hasta 1,5 Mg m-3 en el rango 200-600 mm. A pesar de que el suelo presentó una alta DA antes de aplicar los tratamientos, se observó un incremento significativo de la compactación del subsuelo por las altas intensidades de tráfico aplicadas.Facultad de Ciencias Agrarias y Forestale

Efectos del tráfico del tractor sobre la distribución de la compactación del suelo y los rendimientos de trigo en España

The general objective of this paper was to quantify the changes in the physical properties of an Aridisol soil and the effect on wheat yield due to agricultural tractors traffic in the Vélez Blanco District, Almería Spain. Parameters measured were cone index (CI) in the 0-600 mm depth profile, bulk density (BD) and rut depth; the variable wheat yields (WY) was measured too. The traffic treatments applied were: 0 (control plot), 1, 3, 5, and 7 tractor passes in the same tracks. Each experimental plot was trafficked with two tractors, one light (60 kN) and one heavy (80 kN). In topsoil (0-200 mm), up to five passes of the heavy (HT) and light tractors (LT), as in one and three passes, the BD and CI values responded to the ground pressure being higher in absolute value for LT. For the 200 to 400 mm depth range HT caused higher CI (1,570 to 2,200 kPa) and BD (1.38 to 1.68 Mg m-3) values than LT. Eight months later, WY was evaluated in tractor's track areas and decreases in the range of 18-38%, were measured. For seven passes the applications of total loads of 80 and 60 kN increased BD up to 1.5 Mg m-3 at depths of 200-600 mm. Although soil had high bulk density prior to traffic treatments, a significant increment of subsoil compaction still occurred due to the high traffic intensities applied.El objetivo general del estudio fue cuantificar los cambios producidos en las propiedades físicas de un suelo Aridisol y los efectos sobre el rendimiento del trigo debido al tráfico de tractores agrícolas en Vélez Blanco, Almería, España. Los parámetros analizados fueron índice de cono (IC) a una profundidad de 0-600 mm, densidad aparente (DA) y profundidad de huella; también se analizó la variable rendimiento del trigo (RT). Los tratamientos de tráfico aplicados fueron: cero (parcela testigo), y uno, tres, cinco, y siete pasadas de tractor sobre la misma huella. En cada parcela experimental se utilizaron dos tractores, uno ligero (60 kN) y uno pesado (80 kN). En el horizonte superficial (0-200 mm), hasta las cinco pasadas de los tractores pesados (TP) y ligeros (TL), los valores de DA y de IC respondieron a la presión en el área de contacto, siendo más alto en valor absoluto para TL cuando pasó una y tres veces. Para el rango de profundidad 200-400 mm, TP causó valores más altos de IC (1.570 a 2.200 kPa) y DA (1,38 a 1,68 Mg m-3) que TL. RT se evaluó ocho meses después sobre el área pisada, observándose una disminución en un rango de 18-38%. Las cargas totales aplicadas de 80 y 60 kN, con siete pasadas, aumentaron DA hasta 1,5 Mg m-3 en el rango 200-600 mm. A pesar de que el suelo presentó una alta DA antes de aplicar los tratamientos, se observó un incremento significativo de la compactación del subsuelo por las altas intensidades de tráfico aplicadas.Facultad de Ciencias Agrarias y Forestale

Calculation of quantum discord for qubit-qudit or N qubits

Quantum discord, a kind of quantum correlation, is defined as the difference between quantum mutual information and classical correlation in a bipartite system. It has been discussed so far for small systems with only a few independent parameters. We extend here to a much broader class of states when the second party is of arbitrary dimension d, so long as the first, measured, party is a qubit. We present two formulae to calculate quantum discord, the first relating to the original entropic definition and the second to a recently proposed geometric distance measure which leads to an analytical formulation. The tracing over the qubit in the entropic calculation is reduced to a very simple prescription. And, when the d-dimensional system is a so-called X state, the density matrix having non-zero elements only along the diagonal and anti-diagonal so as to appear visually like the letter X, the entropic calculation can be carried out analytically. Such states of the full bipartite qubit-qudit system may be named "extended X states", whose density matrix is built of four block matrices, each visually appearing as an X. The optimization involved in the entropic calculation is generally over two parameters, reducing to one for many cases, and avoided altogether for an overwhelmingly large set of density matrices as our numerical investigations demonstrate. Our results also apply to states of a N-qubit system, where "extended X states" consist of (2^(N+2) - 1) states, larger in number than the (2^(N+1) - 1) of X states of N qubits. While these are still smaller than the total number (2^(2N) - 1) of states of N qubits, the number of parameters involved is nevertheless large. In the case of N = 2, they encompass the entire 15-dimensional parameter space, that is, the extended X states for N = 2 represent the full qubit-qubit system.Comment: 6 pages, 1 figur