The Cost of Coexistence between Bt Maize and Open Pollinated Maize Varieties in Lowland Coastal Kenya

Kenya is currently in the process of introducing genetically modified maize (Bt maize). A major concern is that the Bt gene might cross into local varieties through cross pollination. Current regulatory strategies to ensure coexistence of the two cropping systems at the farm level rely on spatial isolation measures-separation distances and/or buffer zones. However, the interaction of practical measures and costs of spatial isolation with the farmer’s economic incentive to plant a Bt maize crop have not been studied in Kenya. The purpose of this study was to analyze the technical and economic feasibility of the implementation of spatial coexistence measures. Using spatial geo-referenced data from the actual agricultural landscape in lowland coastal Kenya, the study finds that flexible separation distances hold the possibility of ensuring coexistence in the region, but will be difficult to implement. Rigid buffer strips on the other hand are not consistent with the producers’ economic incentive to plant a Bt maize crop.Coexistence, Regulatory, Spatial, Agro-ecological zone, GM crops, Resource /Energy Economics and Policy,

Participatory Evaluation of Integrated Pest and Soil Fertility Management Options Using Ordered Categorical Data Analysis

During participatory rural appraisals, farmers at the Lake Victoria basin of Kenya and Uganda identified Striga, stemborer and declining soil fertility as three major constraints to maize production To reduce food insecurity, several innovative integrated technologies to address these constraints have been developed, including push-pull (maize intercropped with Desmodium and surrounded by napier grass), maize-soybean and maize-crotalaria rotations, and Imazapyrresistant (IR) maize seed coated with the herbicide. To let farmers evaluate the new technologies, 12 demonstration trials, comparing the different technologies, were established in four villages in Siaya and Vihiga districts (Western Kenya) and two villages in Busia (Uganda). These evaluations, where farmers' appreciation and feedback on the technology are captured, are an important step in technology development. During field days at the end of short rainy seasons of 2003 and 2004, 504 farmers individually observed and rated each treatment under the different cropping systems, with and without IR maize, and with and without fertilizer, with a maize continuous monocrop as control. Farmers scored each of the 16 treatments on an ordered scale of five categories: very poor, poor, average, good, and very good. The treatments were scored for each of the criteria farmers has previously determined (including yield, resistance to Striga and stemborer, and improvement of soil fertility). Analysis of the evaluation, using ordinal regression, show significant differences in farmers' preference by year and site. There was, however, little effect of farm and farmer characteristics such as farm size and gender of the observer. Ordinal regression of farmers' scores are not as intuitive and also bit cumbersome to use, but they have a better theoretical foundation than other methods, in particular the use of means. This paper shows how the method can be used, and concludes that, with some effort, it is a convenient way to analyse farmers' ranking of a large number of options.farmers' preference, technologies, ordinal regression, Crop Production/Industries,

Living in times of war: waste of c. 1600 from two garderobe chutes from the Castle of Middelburg-in-Flanders (Belgium)

The material remains and environmental data recovered during a rescue excavation in 2002-03 in the castle of the new town of Middelburg-in-Flanders throw light on the site, region and landscape in wartime. The paper discusses the historical context at the turn of the 16th century, the excavation of the castle, the taphonomy of the chutes, the analysis of the artefacts and ecological data recovered from two garderobe chutes in the upper court, and concludes with a synthesis focussing on the interpretation of the excavated record in the historically attested natural and socio-economic disruption caused by the Spanish-Dutch War

A Type-Theoretic Account of Neg-Raising Predicates in Tree Adjoining Grammars

International audienceNeg-Raising (NR) verbs form a class of verbs with a clausal complement that show the following behavior: when a negation syntactically attaches to the matrix predicate, it can semantically attach to the embedded predicate. This paper presents an account of NR predicates within Tree Adjoining Grammar (TAG). We propose a lexical semantic interpretation that heavily relies on a Montague-like semantics for TAG and on higher-order types

Concurrent constraint programming with process mobility

We propose an extension of concurrent constraint programming with primitives for process migration within a hierarchical network, and we study its semantics. To this purpose, we first investigate a "pure " paradigm for process migration, namely a paradigm where the only actions are those dealing with transmissions of processes. Our goal is to give a structural definition of the semantics of migration; namely, we want to describe the behaviour of the system, during the transmission of a process, in terms of the behaviour of the components. We achieve this goal by using a labeled transition system where the effects of sending a process, and requesting a process, are modeled by symmetric rules (similar to handshaking-rules for synchronous communication) between the two partner nodes in the network. Next, we extend our paradigm with the primitives of concurrent constraint programming, and we show how to enrich the semantics to cope with the notions of environment and constraint store. Finally, we show how the operational semantics can be used to define an interpreter for the basic calculus.

Decay-assisted collinear resonance ionization spectroscopy: Application to neutron-deficient francium

This paper reports on the hyperfine-structure and radioactive-decay studies of the neutron-deficient francium isotopes $^{202-206}$Fr performed with the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE facility, CERN. The high resolution innate to collinear laser spectroscopy is combined with the high efficiency of ion detection to provide a highly-sensitive technique to probe the hyperfine structure of exotic isotopes. The technique of decay-assisted laser spectroscopy is presented, whereby the isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay tagging of the hyperfine components. Here, we present the first hyperfine-structure measurements of the neutron-deficient francium isotopes $^{202-206}$Fr, in addition to the identification of the low-lying states of $^{202,204}$Fr performed at the CRIS experiment.Comment: Accepted for publication with Physical Review

The two electron artificial molecule

Exact results for the classical and quantum system of two vertically coupled two-dimensional single electron quantum dots are obtained as a function of the interatomic distance (d) and with perpendicular magnetic field. The classical system exhibits a second order structural transition as a function of d which is smeared out and shifted to lower d values in the quantum case. The spin-singlet - spin-triplet oscillations are shifted to larger magnetic fields with increasing d and are quenched for a sufficiently large interatomic distance.Comment: 4 pages, 4 ps figure