Dual citizenship or dual identity? Does 'transnationalism' supplant 'nationalism' among returning Trinidadians?

In this article we focus on the dual identities of relatively young Trinidadians who have decided to return to the island of their birth, or of their parents, while still in their thirties and forties. Highly-educated professional transnational migrants mostly make tip our sample of 36; 26 possess dual citizenship. We focus on our informants' narratives about their transnational experiences, self-appraisals of their dual identities and how they value dual citizenship. More generally, we ask does transnationalism supplant nationalism among our returning informants? Unsurprisingly, the diverse responses we document do not support the commonly held explanatory relationship between return adaptations, 'national belonging' and the expected dominance of 'transnational belonging'. Family, relations intervene significantly, both to encourage transnationalism and to strengthen nationalism. Feelings of notional belonging often accompany transnationalism. Notably, we view dual citizenship strategically and pragmatically as advantageous to the continuation of transnational practices.

The analysis of ranked observations of soil structure using indicator geostatistics

Structure is an important physical feature of the soil that is associated with water movement, the soil atmosphere, microorganism activity and nutrient uptake. A soil without any obvious organisation of its components is known as apedal and this state can have marked effects on several soil processes. Accurate maps of topsoil and subsoil structure are desirable for a wide range of models that aim to predict erosion, solute transport, or flow of water through the soil. Also such maps would be useful to precision farmers when deciding how to apply nutrients and pesticides in a site-specific way, and to target subsoiling and soil structure stabilization procedures. Typically, soil structure is inferred from bulk density or penetrometer resistance measurements and more recently from soil resistivity and conductivity surveys. To measure the former is both time-consuming and costly, whereas observations made by the latter methods can be made automatically and swiftly using a vehicle-mounted penetrometer or resistivity and conductivity sensors. The results of each of these methods, however, are affected by other soil properties, in particular moisture content at the time of sampling, texture, and the presence of stones. Traditional methods of observing soil structure identify the type of ped and its degree of development. Methods of ranking such observations from good to poor for different soil textures have been developed. Indicator variograms can be computed for each category or rank of structure and these can be summed to give the sum of indicator variograms (SIV). Observations of the topsoil and subsoil structure were made at four field sites where the soil had developed on different parent materials. The observations were ranked by four methods and indicator and the sum of indicator variograms were computed and modelled for each method of ranking. The individual indicators were then kriged with the parameters of the appropriate indicator variogram model to map the probability of encountering soil with the structure represented by that indicator. The model parameters of the SIVs for each ranking system were used with the data to krige the soil structure classes, and the results are compared with those for the individual indicators. The relations between maps of soil structure and selected wavebands from aerial photographs are examined as basis for planning surveys of soil structure. (C) 2007 Elsevier B.V. All rights reserved.

The impact of global warming on the tropical Pacific Ocean and El Niño

The El Niño–Southern Oscillation (ENSO) is a naturally occurring fluctuation that originates in the tropical Pacific region and affects ecosystems, agriculture, freshwater supplies, hurricanes and other severe weather events worldwide. Under the influence of global warming, the mean climate of the Pacific region will probably undergo significant changes. The tropical easterly trade winds are expected to weaken; surface ocean temperatures are expected to warm fastest near the equator and more slowly farther away; the equatorial thermocline that marks the transition between the wind-mixed upper ocean and deeper layers is expected to shoal; and the temperature gradients across the thermocline are expected to become steeper. Year-to-year ENSO variability is controlled by a delicate balance of amplifying and damping feedbacks, and one or more of the physical processes that are responsible for determining the characteristics of ENSO will probably be modified by climate change. Therefore, despite considerable progress in our understanding of the impact of climate change on many of the processes that contribute to El Niño variability, it is not yet possible to say whether ENSO activity will be enhanced or damped, or if the frequency of events will change.

Transgenic crops: the current and next generations.

This chapter describes the present status and future prospects for transgenic (genetically modified) crops. It concentrates on the most recent data obtained from patent databases and field trial applications, as well as the usual scientific literature. By these means, it is possible to obtain a useful perspective into future commercial products and international trends. The various research areas are subdivided on the basis of those associated with input (agronomic) traits and those concerned with output (e.g., food quality) characteristics. Among the former group are new methods of improving stress resistance, and among the latter are many examples of producing pharmaceutical compounds in plants.

Quantitative response of the longevity of seed of twelve crops to temperature and moisture in hermetic storage

Seeds of 39 seed lots of a total of twelve different crops were stored hermetically in a wide range of air-dry environments (2-25% moisture content at 0-50 degrees C), viability assessed periodically, and the seed viability equation constants estimated. Within a species, estimates of the constants which quantify absolute longevity (K-E) and the relative effects on longevity of moisture content (C-W) and temperature (C-H and C-Q) did not differ (P >0.05 to P >0.25) among lots. Comparison among the 12 crops provided variant estimates of K-E and C-W (P< 0.01), but common values of C-H and C-Q (0.0322 and 0.000454, respectively, P >0.25). Maize (Zea mays) provided the greatest estimate of K-E (9.993, s.e.= 0.456), followed by sorghum (Sorghum bicolor) (9.381, s.e. 0.428), pearl millet (Pennisetum typhoides) (9.336, s.e.= 0.408), sugar beet (Beta vulgaris) (8.988, s.e.= 0.387), African rice (Oryza glaberrima) (8.786, s.e.= 0.484), wheat (Triticum aestivum) (8.498, s.e.= 0.431), foxtail millet (Setaria italica) (8.478, s.e.= 0.396), sugarcane (Saccharum sp.) (8.454, s.e.= 0.545), finger millet (Eleusine coracana) (8.288, s.e.= 0.392), kodo millet (Paspalum scrobiculatum) (8.138, s.e.= 0.418), rice (Oryza sativa) (8.096, s.e.= 0.416) and potato (Solanum tuberosum) (8.037, s.e.= 0.397). Similarly, estimates of C-W were ranked maize (5.993, s.e.= 0.392), pearl millet (5.540, s.e.= 0.348), sorghum (5.379, s.e.=0.365), potato (5.152, s.e.= 0.347), sugar beet (4.969, s.e.= 0.328), sugar cane (4.964, s.e.= 0.518), foxtail millet (4.829, s.e.= 0.339), wheat (4.836, s.e.= 0.366), African rice (4.727, s.e.= 0.416), kodo millet (4.435, s.e.= 0.360), finger millet (4.345, s.e.= 0.336) and rice (4.246, s.e.= 0.355). The application of these constants to long-term seed storage is discussed.

International public goods through integrated natural resources management research in CGIAR partnerships

The CGIAR System conducts research to produce international public goods (IPG) that are of wide applicability creating a scientific base which speeds and broadens local adaptive development. Integrated natural resources management (INRM) research is sometimes seen to be very location specific and consequently does not lend itself readily to the production of IPGs. In this paper we analyse ways in which strategic approaches to INRM research can have broad international applicability and serve as useful foundations for the development of locally adapted technologies. The paper describes the evolution of the IPG concept within the CGIAR and elaborates on five major types of IPGs that have been generated from a varied set of recent INRM research efforts. CGIAR networks have both strengths and weaknesses in INRM research and application, with enormous differences in relative research and development capacities, responsibilities and data access of its partners, making programme process evolution critical to acceptance and participation. Many of the lessons learnt regarding challenges and corresponding IPG research approaches are relevant to designing and managing future multi-scale, multi-locational, coordinated INRM programmes involving broad-based partnerships to address complex environmental and livelihood problems for development.

Greenhouse whitefly (Homoptera : Aleyrodidae) dispersal under different UV-light environments

The greenhouse whitefly, Dialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae), is known to respond to UV light (UV). Field studies were conducted to improve our understanding of the behavioral effects and practical implications of using UV-blocking plastic films for the control of whitefly. Adult whiteflies were released in outdoor-located choice-chamber experiments with compartments clad with a range of films that transmitted incident UV to different extents. In release-recapture experiments, a very small proportion of the whiteflies recovered had dispersed into compartments where the entire UV spectrum was blocked, whereas the major proportion preferred compartments with UV. Compartments clad with films that blocked LTV below 375 nm attracted significantly more whiteflies than films that blocked UV below 385 nm, whereas the absorption of LTV wavelengths above 385 nm did not show any further effect on whitefly numbers. A reduction in the side cladding of the compartments by > 20% significantly reduced the advantage of using LTV-blocking films. Adult whitefly did not discriminate between direct- and diffused-light environments, as long as the UV-absorbing properties of the films were equivalent. Whitefly dispersal was influenced by the time of the day when adult whitefly were released, with a higher proportion of whitelly avoiding compartments clad with LTV-blocking films, at times of the day when light intensities were higher. The future use of UV-blocking films as a potentially highly effective component of integrated pest management systems for the control of whitefly is discussed.

Amplified fragment length polymorphism genetic fingerprinting challenges the taxonomic status of the near-endemic species Chara curta Nolte ex Kutz. (Characeae)

Amplified fragment length polymorphism (AFLP) genetic fingerprinting of 14 accessions of Chara curta and Chara aspera Willd., sampled across a range of habitats and morphologies in Britain, suggests that these taxa are part of the variation within a single species complex. Two primer combinations generating 397 fragments (97% of which were polymorphic), analysed by Jaccard's similarity coefficient and principal co-ordinate analysis, did not recover groups which reflect the current taxonomy. By contrast with the genetic study, a Gower general similarity coefficient and principal co-ordinate analysis of 52 morphological characters recovered the currently recognized species groups. A Mantel test showed no significant correlation between the genetic data and the morphological data, supporting the hypothesis that phenotypic variability in Chara L. is either to some extent environmentally induced or represents developmental stages. Implications for the conservation status of C. curta in Britain are discussed. (c) 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 467-476.

Nucleic acid recovery from complex environmental samples

Effective extraction of nucleic acid from environmental samples is an essential starting point in the molecular analysis of microbial communities in the environment. However, there are many different extraction methods in the literature and deciding which one is best suited to a particular sample is very difficult. This article details the important steps and choices in deciding how to extract nucleic acids from environmental samples and gives specific details of one method that has proven very successful at extracting DNA and RNA from a range of different samples.