Action versus Result-Oriented Schemes in a Grassland Agroecosystem: A Dynamic Modelling Approach

Effects of agri-environment schemes (AES) on biodiversity remain controversial. While most AES are action-oriented, result-oriented and habitat-oriented schemes have recently been proposed as a solution to improve AES efficiency. The objective of this study was to compare action-oriented, habitat-oriented and result-oriented schemes in terms of ecological and productive performance as well as in terms of management flexibility. We developed a dynamic modelling approach based on the viable control framework to carry out a long term assessment of the three schemes in a grassland agroecosystem. The model explicitly links grazed grassland dynamics to bird population dynamics. It is applied to lapwing conservation in wet grasslands in France. We ran the model to assess the three AES scenarios. The model revealed the grazing strategies respecting ecological and productive constraints specific to each scheme. Grazing strategies were assessed by both their ecological and productive performance. The viable control approach made it possible to obtain the whole set of viable grazing strategies and therefore to quantify the management flexibility of the grassland agroecosystem. Our results showed that habitat and result-oriented scenarios led to much higher ecological performance than the action-oriented one. Differences in both ecological and productive performance between the habitat and result-oriented scenarios were limited. Flexibility of the grassland agroecosystem in the result-oriented scenario was much higher than in that of habitat-oriented scenario. Our model confirms the higher flexibility as well as the better ecological and productive performance of result-oriented schemes. A larger use of result-oriented schemes in conservation may also allow farmers to adapt their management to local conditions and to climatic variations

Nutrient provision capacity of alternative livestock farming systems per area of arable farmland required

Although climate impacts of ruminant agriculture are a major concern worldwide, using policy instruments to force grazing farms out of the livestock industry may diminish opportunities to produce nutritious food without exacerbating the food-feed competition for fertile and accessible land resources. Here, we present a new set of quantitative evidence to demonstrate that, per unit of overall nutrient value supplied by a given commodity, the demand for land suitable for human-edible crop production is considerably smaller under ruminant systems than monogastric systems, and consistently so at both farm and regional scales. We also demonstrate that imposition of a naïvely designed “red meat tax” has the potential to invite socioeconomic losses far greater than its environmental benefits, due largely to the induced misallocation of resources at the national scale. Our results reiterate the risk inherent in an excessively climate-focused debate on the role of livestock in human society and call for more multidimensional approaches of sustainability assessment to draw better-balanced policy packages

Synthesis and controlled release properties of 2,4-dichlorophenoxy acetate–zinc layered hydroxide nanohybrid

Direct reaction of ZnO with 2,4-dichlorophenoxyacetic acid (24D) solutions of different concentrations allows obtaining new organic–inorganic nanohybrid materials formed by intercalation of 24D into interlayers of zinc layered hydroxide (ZLH). XRD patterns show a progressive evolution of the structure as 24D concentration increases. The nanohybrid obtained at higher 24D concentration (24D–ZLH(0.4)) reveals a well ordered layered structure with two different basal spacings at 25.2 Å and 24 Å. The FTIR spectrum showing the vibrations bands of the functional groups of 24D and of the ZLH confirms the intercalation. SEM images are in agreement with the structural evolution observed by XRD and reveal the ribbon morphology of the nanohybrids. The release studies of 24D showed a rapid release of 94% for the first 100 min governed by the pseudo-second order kinetic model

Estado del arte de la quinua en el mundo en 2013

Alimento de base de las poblaciones andinas desde hace milenios, la quinua se ha convertido hoy en un producto apreciado en el mercado internacional de alimentos dietéticos, orgánicos y equitativos. Este cambio lo iniciaron los mismos productores del Altiplano Sur de Bolivia hace aproximadamente unos 40 años. En medio de un desierto de altura, ellos lograron desarrollar una floreciente producción agrícola de exportación. Aunque cuentan con lucrativos nichos de mercado, los productores de quinua no son agricultores especializados, ni residen de forma permanente en la zona de producción. Estas son algunas de las paradojas que caracterizan la producción de quinua en el Altiplano Sur de Bolivia. Después de describir el origen, la diversidad y los rasgos biológicos del ecotipo Quinua Real en el cual se basa la producción de esta zona, se plantea la importancia de la quinua en los agrosistemas locales y, más allá, en los sistemas de actividades agrícolas y no agrícolas manejados por las familias del Altiplano Sur. Movilidad geográfica y pluriactividad forman parte del modo de vida ancestral de estas poblaciones y determinan hasta hoy en día las condiciones de uso de los recursos territoriales y la organización de los productores en el contexto del auge comercial de la quinua. La producción actual de quinua en la región presenta rasgos de vulnerabilidad agroecológica y social, así como capacidades adaptativas para enfrentarlos. Se resaltan como puntos clave para la sostenibilidad de los agrosistemas locales : i) la concertación de reglas comunales e individuales para el acceso y uso de la tierra en agrosistemas socialmente equitativos y equilibrados entre cultivo y ganadería, ii) las normas internacionales para el reconocimiento de la Quinua Real en los mercados de exportación, iii) una actualización continua de las reglas y normas para mantener la adaptabilidad de los agrosistemas locales a los cambios imprevisibles del contexto socio-ecológico a varias escalas de espacio y de tiempo

Exciting surface plasmons with transformation media

The final publication is available at Springer via http://dx.doi.org/10.1007/s11468-012-9361-5We present a way of exciting surface plasmon polaritons along non-patterned metallic surfaces by means of a flat squeezing slab designed with transformation optics. The slab changes the dispersion relation of incident light, enabling evanescent coupling to propagating surface plasmons. Unlike prism couplers, the proposed device does not introduce reflections at its input interface. Moreover, its compact geometry is suitable for integration. A feasible dielectric implementation of the coupler is suggested. Finally, we show that the angular response of the device can be engineered by using a non-uniform compression factor. As an example, we design a coupler with a half-power angular bandwidth 2. 5 times higher than that of a conventional dielectric coupler. © 2012 Springer Science+Business Media, LLC.Financial support by Spanish Ministerio de Ciencia e Innovacion (contracts CSD2008-00066 and TEC2008-06871-C02, and FPU grant) is gratefully acknowledged.García Meca, C.; Ortuño Molinero, R.; Martí Sendra, J.; Martínez Abietar, AJ. (2012). Exciting surface plasmons with transformation media. Plasmonics. 7(4):701-707. https://doi.org/10.1007/s11468-012-9361-5S70170774Raether H (1988) Surface plasmons on smooth and rough surfaces and on gratings. Springer-Verlag, BerlinBarnes WL, Dereux A, Ebbesen TW (2003) Surface plasmon subwavelength optics. Nature 424:824–830Maier SA (2007) Plasmonics: fundamentals and applications. Springer, New YorkSchuller JA, Barnard ES, Cai W, Jun YC, White JS, Brongersma ML (2010) Plasmonics for extreme light concentration and manipulation. Nat Mater 9:193–204Brongersma ML, Shalaev VM (2010) The case for plasmonics. Science 328:440–441Liu Y, Zentgraf T, Bartal G, Zhang X (2010) Transformational plasmon optics. Nano Lett 10:1991–1997Huidobro PA, Nesterov ML, Martín-Moreno L, García-Vidal FJ (2010) Transformation optics for plasmonics. Nano Lett 10:1985–1990Kadic M, Guenneau S, Enoch S (2010) Transformational plasmonics: cloak, concentrator and rotator for SPPs. Opt Express 18:12027–12032Zhang J, Xiao S, Wubs M, Mortensen NA (2011) Surface plasmon wave adapter designed with transformation optics. ACS Nano 5:4359–4364Pendry JB, Schurig D, Smith DR (2006) Controlling electromagnetic fields. Science 312:1780–1782Leonhardt U (2006) Optical conformal mapping. Science 312:1777–1780Leonhardt U, Philbin TG (2006) General relativity in electrical engineering. New J Phys 8:247Sambles JR, Bradbery GW, Yang F (1991) Optical excitation of surface plasmons: an introduction. Contemp Phys 32:173–183Rahm M, Roberts DA, Pendry JB, Smith DR (2008) Transformation-optical design of adaptive beam bends and beam expanders. Opt Express 16:11555–11567Vasic B, Isic G, Gajic R, Hingerl K (2009) Coordinate transformation based design of confined metamaterial structures. Phys Rev B 79:85103Tichit P, Burokur SN, Lustrac A (2009) Waveguide taper engineering using coordinate transformation technology. Opt Express 18:767–772Zang X, Jiang C (2010) Manipulating the field distribution via optical transformation. Opt Express 18:10168–10176García-Meca C, Tung MM, Galán JV, Ortuño R, Rodríguez-Fortuño FJ, Martí J, Martínez A (2011) Squeezing and expanding light without reflections via transformation optics. Opt Express 19:3562–3575Li J, Han S, Zhang S, Bartal G, Zhang X (2009) Designing the Fourier space with transformation optics. Opt Lett 34:3128–3130Li J, Pendry JB (2008) Hiding under the carpet: a new strategy for cloaking. Phys Rev Lett 101:20390