The resilience of indigenous knowledge in small-scale African agriculture: key drivers

The successful use of indigenous knowledge (IK) in development practice in rural Africa over the last couple of decades has proved to be elusive and disappointing. Using empirical field data from northern Malawi, this study suggests that the two key drivers for farmers in this area are household food security and the maintenance of soil fertility. Indigenous ways of knowing underpin the agricultural system which has been developed, rather than the adoption of more modern, ‘scientific’ ways, to deliver against these drivers. Such IKs, however, are deeply embedded in the economic, social and cultural environments in which they operate

Symbolic Algorithms for Language Equivalence and Kleene Algebra with Tests

We first propose algorithms for checking language equivalence of finite automata over a large alphabet. We use symbolic automata, where the transition function is compactly represented using a (multi-terminal) binary decision diagrams (BDD). The key idea consists in computing a bisimulation by exploring reachable pairs symbolically, so as to avoid redundancies. This idea can be combined with already existing optimisations, and we show in particular a nice integration with the disjoint sets forest data-structure from Hopcroft and Karp's standard algorithm. Then we consider Kleene algebra with tests (KAT), an algebraic theory that can be used for verification in various domains ranging from compiler optimisation to network programming analysis. This theory is decidable by reduction to language equivalence of automata on guarded strings, a particular kind of automata that have exponentially large alphabets. We propose several methods allowing to construct symbolic automata out of KAT expressions, based either on Brzozowski's derivatives or standard automata constructions. All in all, this results in efficient algorithms for deciding equivalence of KAT expressions

Unidimensional model of the ad-atom diffusion on a substrate submitted to a standing acoustic wave I. Derivation of the ad-atom motion equation

The effect of a standing acoustic wave on the diffusion of an ad-atom on a crystalline surface is theoretically studied. We used an unidimensional space model to study the ad-atom+substrate system. The dynamic equation of the ad-atom, a Generalized Langevin equation, is analytically derived from the full Hamiltonian of the ad-atom+substrate system submitted to the acoustic wave. A detailed analysis of each term of this equation, as well as of their properties, is presented. Special attention is devoted to the expression of the effective force induced by the wave on the ad-atom. It has essentially the same spatial and time dependences as its parent standing acoustic wave

Internal convection in thermoelectric generator models

Coupling between heat and electrical currents is at the heart of thermoelectric processes. From a thermal viewpoint this may be seen as an additional thermal flux linked to the appearance of electrical current in a given thermoelectric system. Since this additional flux is associated to the global displacement of charge carriers in the system, it can be qualified as convective in opposition to the conductive part associated with both phonons transport and heat transport by electrons under open circuit condition, as, e.g., in the Wiedemann-Franz relation. In this article we demonstrate that considering the convective part of the thermal flux allows both new insight into the thermoelectric energy conversion and the derivation of the maximum power condition for generators with realistic thermal coupling.Comment: 8 pages, 3 figure

Using species richness and functional traits predictions to constrain assemblage predictions from stacked species distribution models

Aim: Modelling species at the assemblage level is required to make effective forecast of global change impacts on diversity and ecosystem functioning. Community predictions may be achieved using macroecological properties of communities (MEM), or by stacking of individual species distribution models (S-SDMs). To obtain more realistic predictions of species assemblages, the SESAM framework suggests applying successive filters to the initial species source pool, by combining different modelling approaches and rules. Here we provide a first test of this framework in mountain grassland communities. Location: The western Swiss Alps. Methods: Two implementations of the SESAM framework were tested: a "Probability ranking" rule based on species richness predictions and rough probabilities from SDMs, and a "Trait range" rule that uses the predicted upper and lower bound of community-level distribution of three different functional traits (vegetative height, specific leaf area and seed mass) to constraint a pool of environmentally filtered species from binary SDMs predictions. Results: We showed that all independent constraints expectedly contributed to reduce species richness overprediction. Only the "Probability ranking" rule allowed slightly but significantly improving predictions of community composition. Main conclusion: We tested various ways to implement the SESAM framework by integrating macroecological constraints into S-SDM predictions, and report one that is able to improve compositional predictions. We discuss possible improvements, such as further improving the causality and precision of environmental predictors, using other assembly rules and testing other types of ecological or functional constraints

Restaurante Universitario París-Francia

This article covers the features of a university dining hall consisting of five rooms with a total capacity for 1,560 diners, plus kitchen facilities. Also examined are the mechanical facilities, such as heating, ventilation, electrical and gas. The utensil and equipment used in each area of the dining hall are shown as well.Se consideran en este artículo las características de un restaurante universitario, con cinco salones-restaurante de 1.560 plazas en total, y cocina. También se analizan las principales instalaciones técnicas: calefacción, ventilación, electricidad y gas; se pueden apreciar los aparatos y utensilios necesarios en cada zona del restaurante

Grupo Escolar Solferino Colombes-Francia

This school complex is divided into three different facilities, one for boys, one for girls and a kindergarten, all in a two-storey Steel structure building. The dining halls and kitchen are located in a separate building connected to the main one, the toilets and the medical department, being a part of the connecting area. The design of the entire complex is highly decorative and yet, very functional.Este Grupo Escolar está formado por tres escuelas destinadas, cada una de ellas, a niñas, niños y jardín de infancia. Se halla instalado en un edificio de dos plantas, realizado a base de estructura metálica. Los comedores y la cocina se han situado en un edificio anexo. En la zona de comunicación entre los dos edificios se encuentran los lavabos y el departamento médico. Todo el conjunto se ha desarrollado de una manera muy decorativa y, a la vez, cómoda

Caja de Previsión París-Francia

The building housing the Pension Fund has three concrete undergrade levels and several floors above grade with a steel structure. This article analyses the layout of each floor and the construction method and materials used in the various areas throughout the building. Also described are the features of the mechanical installations, such as: heating, air conditioning, electrical, lifts and telephone. A 12-storey tower rises from the centre of the building to house the archives, fitted with a telephone equipped elevator.La sede de la Caja de Previsión consta de tres sótanos realizados en hormigón armado, y una superestructura metálica de varias plantas. En este artículo se analiza la distribución de cada una de estas plantas, así como el sistema de construcción y los materiales empleados en las diversas partes del edificio. Se contemplan, también, las características de las instalaciones: calefacción, aire acondicionado, electricidad, ascensores y servicio telefónico. En la parte central del edificio se halla una torre, destinada a archivos, de 12 plantas, dotada de un ascensor con teléfono

Affine convex body semigroups

In this paper we present a new kind of semigroups called convex body semigroups which are generated by convex bodies of R^k. They generalize to arbitrary dimension the concept of proportionally modular numerical semigroup of [7]. Several properties of these semigroups are proven. Affine convex body semigroups obtained from circles and polygons of R^2 are characterized. The algorithms for computing minimal system of generators of these semigroups are given. We provide the implementation of some of them