May the inclusion of a legume crop change weed composition in cereal fields? Example of sainfoin in Aragon (Spain)

Onobrychis viciifolia (Scop.) (sainfoin) is promoted in the Spanish Aragón region through the Agro-Environmental Schemes (AES) since 2007 with the aim of enhancing biodiversity. Also, in other countries, the interest in this legume crop is growing due to its rusticity and beneficial effects on the soil and livestock. However, the effect of the crop on weed flora in the subsequent cereal crops has hardly been investigated yet. With this aim, weed flora has been characterised in 2011–2014 in sainfoin fields in the second and third year of establishment (S2 and S3), in cereal monocrop (CM), in cereal after sainfoin (CS) and in organic cereal fields (OC). Additionally, the soil seedbank was determined in two years in CM and S3 fields. Weed species richness of emerged flora and of the soil seedbank was highest for sainfoin and lowest for CM, being intermediate for OC and CS regardless of the sampling year. The most feared weed species in winter cereal did not increase by growing sainfoin or in CS compared to CM. Curiously, summer annuals dominated in the soil seedbank. Sainfoin fields cause thus a shift in the weed flora, which does not seem to damage subsequent cereal crops provided fields are mouldboard ploughed after sainfoin

Seguimiento de dependientes del alcohol y/o de la cocaína después de su salida de una Comunidad Terapéutica: estudio piloto

En España, las Comunidades Terapéuticas (CT) constituyen un modelo de tratamiento común en las adicciones, aunque apenas existe investigación acerca de su eficacia y la persistencia de sus logros. Objetivos: Evaluar los efectos a corto, medio y largo plazo del tratamiento de la adicción al alcohol o cocaína en las CT de la “Fundación Salud y Comunidad”. Diseño: Estudio piloto descriptivo, con un diseño secuencial de cohorte. Se aplicó una encuesta diseñada ad hoc a 91 usuarios para conocer su evolución en los diferentes periodos de seguimiento (1, 3, 5 ó 10 años después de su salida de la CT): variables sociodemográficas, de uso de la/s sustancia/s psicoactiva/s y relacionadas con la estancia en la CT. Se describe el cambio entre antes de la CT y en la actualidad respecto a variables académicas, laborales, de consumo de droga/s, salud, adaptación socio-familiar y comportamiento delictivo. Resultados: las cohortes mostraron un patrón previo relativamente común, recibiendo un tratamiento similar. Los usuarios afirman haber disminuido el hábito de consumo frecuente de la droga principal, encontrando un 48.9% que no ha recaído ni siquiera mediante un consumo ocasional de la/s droga/s. También perciben haber mejorado su salud y sus relaciones familiares, así como el comportamiento agresivo y problemas legales derivados del consumo de droga/s. Conclusiones: tras su rehabilitación en una CT, los usuarios manifiestan una disminución global del consumo de drogas y perciben una mejora a nivel de salud, familia, violencia y problemáticas derivadas del consumo

Optimisation des paramètres photovoltaïques du CIGS a l aide du simulateur AMPS-1D

[FR] Le Silicium Indium de Gallium et Cuivre (CIGS) dans sa structure chalcopyrite possède des propriétés électriques et électroniques intéressantes. Notre étude a porté sur la concentration de dopage des différentes couches constituant le CIGS et les effets des contacts avant et arrière sur les performances photovoltaïques de la cellule solaire. Nous avons fait la simulation de la variation de la concentration de dopage des différentes couches constituant le CIGS à l¿aide d¿AMPS-1D. Les effets du dopage des différentes couches constituant la cellule solaire à base de CIGS sur les paramètres photovoltaïques tel que le rendement (¿) la tension de circuit ouvert (Vco) et la densité de court-circuit(Jsc) ont été étudiés.L¿augmentation de la concentration de dopage des couches a un effet sur les performances des cellules solaires. Le plus grand rendement a été obtenu lorsqu¿on a augmenté la concentration dedopage de la couche absorbeur. L¿augmentation des conditions aux limites du contact avant diminue le rendement des cellules photovoltaïques tandis que l¿augmentation des conditions aux limites du contact arrière l¿augmente.[EN] Copper indium gallium (di) selenide (CIGS) in its chalcopyrite structure has electrical and electronic properties. Our study focused on the doping of the various layers constituting the CIGS and the effects of the front and back contacts on the photovoltaic performance of the solar cell. We simulated the variation of the doping concentration of the various layers constituting the CIGS using AMPS-1D. The effects of the doping of the various layers of the CIGS solar cell on the photovoltaic parameters such as the efficiency (¿) open circuit voltage (Vco) and the court circuit density (Jsc) have been analyzed. The increase in the doping of the layers has an effect on the performance of the solar cells. The greatest efficiency was obtained when the doping of the absorbed layer is height. The increase in the boundary conditions of the front contact decreases the efficiency of the photovoltaic cells while the increase in boundary conditions of the back contact increases.Oyedele, S.; Boko, A.; Marí, B. (2017). Optimisation des paramètres photovoltaïques du CIGS a l aide du simulateur AMPS-1D. Afrique Science. 13(2):274-283. http://hdl.handle.net/10251/101852S27428313

Synthesis of Perfectly Oriented MAPb0.93Cr0.07Br3 Perovskite Crystals for Thin-Film Photovoltaic Applications

[EN] Wide band gap methylammonium lead halide perovskites (CH3NH3PbX3, X=halogen; CH3NH3: MA) are interesting materials for photovoltaic applications. They have recently gained substantial attention because of their high efficiency, low cost, superior optical properties. The most attractive and representative perovskites are methylammonium lead halides (CH3NH3PbX3,) denoted as MAPbX3, X = Br, Cl, I. usually the optical and structural properties of CH3NH3PbBr3 can be adjusted by introducing other extrinsic ions such as chloride and bromide. In this work, instead of replacing the halogens I or Cl with bromine (Br) as usual, we preferred to act on the post-transition metal (Pb). To this end, we replaced lead with chromium (Cr) which is a transition metal and may have the same oxidation state (+2) as lead. MAPb0.93Cr0.07Br3 thin films were deposited on ITO substrate by the spin coating process. X-ray diffraction analyses indicated the formation of a cubic perovskite with space group Pm3 m. The structural analysis reveals films with (110) and (220) as main peaks. Deposited films showed a strong absorbance in the UV¿vis range. The band gap values were estimated from absorbance measurements. It was found between 1.60 and 1.80 eV. SEM analysis shows a morphology with good coverage and no apparent crystal orientation.Soro, D.; Sidibé, M.; Fassinou, W.; Marí, B.; Sall, T.; Fofana, B.; Boko, A.... (2017). Synthesis of Perfectly Oriented MAPb0.93Cr0.07Br3 Perovskite Crystals for Thin-Film Photovoltaic Applications. International Journal of Innovative Research in Science, Engineering and Technology. IJIRSET (Online). 6(6):10170-10176. doi:10.15680/IJIRSET.2017.0606007S10170101766

Quaternionic Soliton Equations from Hamiltonian Curve Flows in HP^n

A bi-Hamiltonian hierarchy of quaternion soliton equations is derived from geometric non-stretching flows of curves in the quaternionic projective space $HP^n$. The derivation adapts the method and results in recent work by one of us on the Hamiltonian structure of non-stretching curve flows in Riemannian symmetric spaces $M=G/H$ by viewing $HP^n \simeq {\rm U}(n+1,H)/{\rm U}(1,H) \times {\rm U}(n,H)\simeq {\rm Sp}(n+1)/{\rm Sp}(1)\times {\rm Sp}(n)$ as a symmetric space in terms of compact real symplectic groups and quaternion unitary groups. As main results, scalar-vector (multi-component) versions of the sine-Gordon (SG) equation and the modified Korteveg-de Vries (mKdV) equation are obtained along with their bi-Hamiltonian integrability structure consisting of a shared hierarchy of quaternionic symmetries and conservation laws generated by a hereditary recursion operator. The corresponding geometric curve flows in $HP^n$ are shown to be described by a non-stretching wave map and a mKdV analog of a non-stretching Schrodinger map.Comment: 25 pages; typos correcte

Estudio del comportamiento del hormigón armado ante esfuerzos normales y tangentes mediante modelos seccionales de interacción completa

Frame structural analysis has been traditionally based on classic beam theories whose starting hypotheses imply the existence of solely normal stresses in the cross-section or, in some cases, shear stresses in simplified fashion. These methods have been satisfactorily used in the nonlinear analysis of structures dominated by normal forces. Further, there have been many intends to directly extend them to non-linear analysis of concrete structure under more general loading where the theories cannot be applied in a general fashion due to the inclined cracking and anisotropic material behavior. Hence, real structural response under important shear, torsion or confinement cannot be suitably reproduced by traditional beam methods. In this paper, the advantages of frame element idealization of structures are analyzed and the applicability range of traditional schemes considering only normal stresses is defined. A sectional model capable of reproducing 3D stress states in the cross-section domain is briefly presented and used to analyze the response of sections and continuous structures under load cases influenced by tangential forces and confinement. It should be highlighted that the real distribution of normal stresses may be modified in the cracked zone of the beam and affect the structural stiffness. Hence, a shift in the stresses of transverse reinforcement under concomitant bending moments with shear is to be noted as the reciprocal manifestation of the well-known shift of stresses in the longitudinal reinforcements. On the other hand, the model allows a more realistic representation of actual shear patterns of beams and evaluation of actual rotation capacity on length of plastic regions.El análisis tradicional de estructuras reticulares se basa en las teorías clásicas de vigas cuyas hipótesis de partida implican la única existencia de tensiones normales en la sección transversal o, en algunos casos, también tensiones tangenciales con simplificaciones más o menos acertadas. Su aplicación resulta satisfactoria en casos dominados por solicitaciones normales. Existen varios intentos de extenderlos directamente al análisis no lineal de estructuras de hormigón con cargas arbitrarias donde dichas teorías no son aplicables estrictamente debido, entre otras cosas, a la fisuración diagonal. Así pues, la respuesta real ante solicitaciones importantes del tipo cortante, torsión o confinamiento, no puede ser reproducida adecuadamente por los métodos tradicionales. En este artículo se analizan las ventajas del análisis seccional y se define hasta qué punto considerar sólo el efecto de los esfuerzos normales puede resultar suficiente. Se presenta brevemente un modelo que permite reproducir estados tensionales tridimensionales a nivel seccional y se emplea para analizar estructuras sometidas a casos con notable influencia de esfuerzos tangenciales y confinamiento y se investiga la incidencia práctica en la respuesta de secciones y estructuras continuas. Se resalta la existencia de una distribución de tensiones normales modificada en la zona de tracciones que puede afectar la rigidez real de la estructura. Asimismo, se manifiesta un efecto dual al incremento de tracciones en la armadura longitudinal consistente en un incremento de tracciones en la armadura transversal con momento concomitante. Por otro lado, el modelo permite una representación más real de la fisuración en vigas y evidencia una mayor capacidad de rotación plástica antes de la rotura

Mussel Shells from Marine Aquaculture Act like Ecosystem Engineers: Legacy Effects on Benthic Communities

Ecosystem engineers are organisms that cause changes in the physical state of biotic and abiotic structures that modulate the availability of resources to other species, thus affecting biochemical cycles. Molluscs, especially bivalves such as mussels, are widespread in coastal environments and they are excellent ecosystem engineers because of the durability of their shells, which add complexity and heterogeneity to benthic environments. The presence of mussel farms favours the accumulation of shells in benthic environments and may influence surrounding bare sediments, with potential legacy effects on benthic communities. We studied the effects of the accumulation of mussel shells at finfish farms and mussel farms by experimentally comparing bare sediment and sediment with fragmented shells in terms of the abundance of the most relevant faunal groups, specifically polychaete families as well as physical–chemical variables in sediment water samples, specifically organic matter (OM), redox potential, and acid-volatile sulphides (AVS) NH4+ and PO43−. The experiment was replicated under two environmental conditions over a period of 35 days: eutrophic muddy sediments and oligotrophic sandy sediments. The OM and AVS values were significantly higher in the eutrophic sediment with mussel shells. Only NH4+ was positively affected by the mussel shells in the oligotrophic conditions. Differences between the two environments were observed, and the effect of the mussel shells on the polychaete assemblages was more significant in the oligotrophic conditions. Mussel shell accumulations affected the structure of benthic assemblages by modifying their heterogeneity and complexity, which suggests that the presence of mussel farms above bare sediment may affect ecosystem functioning. Aquaculture has potentially negative or positive effects that must be addressed on a large scale, considering the increased input of organic matter and also the simultaneous presence of mussel shell waste, both of which alter the surrounding environment. This is particularly important in oligotrophic sandy sediment.This research was funded by the project CGL2015-70136-R from the Spanish National Agency for Research (MINECO/FEDER)