Economic and physical determinants of the global distributions of crop pests and pathogens

Crop pests and pathogens pose a significant and growing threat to food security, but their geographical distributions are poorly understood. We present a global analysis of pest and pathogen distributions, to determine the roles of socioeconomic and biophysical factors in determining pest diversity, controlling for variation in observational capacity among countries. Known distributions of 1901 pests and pathogens were obtained from CABI. Linear models were used to partition the variation in pest species per country amongst predictors. Reported pest numbers increased with per capita gross domestic product (GDP), research expenditure and research capacity, and the influence of economics was greater in micro-organisms than in arthropods. Total crop production and crop diversity were the strongest physical predictors of pest numbers per country, but trade and tourism were insignificant once other factors were controlled. Islands reported more pests than mainland countries, but no latitudinal gradient in species richness was evident. Country wealth is likely to be a strong indicator of observational capacity, not just trade flow, as has been interpreted in invasive species studies. If every country had US levels of per capita GDP, then 205 +/- 9 additional pests per country would be reported, suggesting that enhanced investment in pest observations will reveal the hidden threat of crop pests and pathogens

The Impact of Shape on the Perception of Euler Diagrams

Euler diagrams are often used for visualizing data collected into sets. However, there is a significant lack of guidance regarding graphical choices for Euler diagram layout. To address this deficiency, this paper asks the question `does the shape of a closed curve affect a user's comprehension of an Euler diagram?' By empirical study, we establish that curve shape does indeed impact on understandability. Our analysis of performance data indicates that circles perform best, followed by squares, with ellipses and rectangles jointly performing worst. We conclude that, where possible, circles should be used to draw effective Euler diagrams. Further, the ability to discriminate curves from zones and the symmetry of the curve shapes is argued to be important. We utilize perceptual theory to explain these results. As a consequence of this research, improved diagram layout decisions can be made for Euler diagrams whether they are manually or automatically drawn

Hyper-Raman scattering analysis of the vibrations in vitreous boron oxide

Hyper-Raman scattering has been measured on vitreous boron oxide, $v-$B$_2$O$_3$. This spectroscopy, complemented with Raman scattering and infrared absorption, reveals the full set of vibrations that can be observed with light. A mode analysis is performed based on the local D$_{3h}$ symmetry of BO$_3$ triangles and B$_3$O$_3$ boroxol rings. The results show that in $v-$B$_2$O$_3$ the main spectral components can be succesfully assigned using this relatively simple model. In particular, it can be shown that the hyper-Raman boson peak arises from external modes that correspond mainly to librational motions of rigid boroxol rings.Comment: 13 pages, 11 figures, 2 table

Synthesis and self-assembly of polyimide/poly(dimethylsiloxane) brush triblock copolymers

A series of novel brush triblock copolymers containing 'glassy' fluorinated polyimide, poly((4,4'-hexafluoroisopropylidene diphthalic anhydride)-co-(2,3,5,6-tetramethyl-1,4-phenylenediamine)) (poly(6FDA-co-TMPD)), and 'rubbery' polydimethylsiloxane monomethacrylate (PDMS-MA) were synthesized and characterized. Well-defined difunctional poly(6FDA-co-TMPD) with a,w-amino end-groups was initially prepared via step-growth polymerization using precise control of the diamine (TMPD) to dianhydride (6FDA) ratio. Subsequent functionalization with 2-bromoisobutyryl bromide afforded a telechelic macroinitiator suitable for atom transfer radical polymerization (ATRP). The macroinitiator and its diamino poly(6FDA-co-TMPD) precursor were characterized via gel permeation chromatography (GPC), 1H nuclear magnetic resonance (NMR) spectroscopic analysis and matrix assisted laser desorption ionization time-of-flight (MALDI ToF) mass spectroscopy. ATRP of PDMS-MA using the macroinitiator in different molar ratios afforded a series of brush triblock copolymers with high monomer conversions (88-94%) and varying PDMS weight fractions. Self-assembly of the triblock brush copolymers in dimethylformamide (DMF) afforded nanoparticles with hydrodynamic diameters (dH) ranging from 87 to 109 nm, as determined by dynamic light scattering (DLS) analysis. Cross-linking of the nanoparticles was achieved via hydrogen abstraction through the thermal degradation of benzoyl peroxide. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) revealed that the self-assemblies and their cross-linked derivatives had spherical morphologies

Using climate information to support crop breeding decisions and adaptation in agriculture

Population growth in the next few decades will increase the need for food production, while the yields of major food crops could be impacted by the changing climate and changing threats from pests and pathogens. Crop breeding, both through conventional techniques, and GM assisted breeding could help meet these challenges, if adequately supported by appropriate information on the future climate. We highlight some of the major challenges for crop breeders and growers in the coming decades, and describe the main characteristics of crop breeding techniques and other adaptation options for agriculture. We review recent uses of climate information to support crop breeding decisions and make recommendations for how this might be improved. We conclude that there is significant potential for breeders to work more closely with climate scientists and crop modellers in order to address the challenges of climate change. It is not yet clear how climate information can best be used. Fruitful areas of investigation include: provision of climate information to identify key target breeding traits and develop improved success criteria (e.g. for heat/drought stress); identification of those conditions under which multiple stress factors (for example, heat stress, mid-season drought stress, flowering drought stress, terminal drought stress) are important in breeding programmes; use of climate information to inform selection of trial sites; identification of the range of environments and locations under which crop trials should be performed (likely to be a wider range of environments than done at present); identification of appropriate duration of trials (likely to be longer than current trials, due to the importance of capturing extreme events); and definition of appropriate methods for incorporating climate information into crop breeding programmes, depending on the specific needs of the breeding programme and the strengths and weaknesses of available approaches. Better knowledge is needed on climate-related thresholds important to crop breeders, for example on the frequency and severity of extreme climate events relevant to the product profile, or to help provide tailored climate analyses (particularly for extreme events). The uncertainties inherent in climate and impact projections provide a particular challenge for translating climate science into actionable outcomes for agriculture. Further work is needed to explore relevant social and economic assumptions such as the level and distribution of real incomes, changing consumption patterns, health impacts, impacts on markets and trade, and the impact of legislation relating to conservation, the environment and climate change

Cliophysics: Socio-political Reliability Theory, Polity Duration and African Political (In)stabilities

Quantification of historical sociological processes have recently gained attention among theoreticians in the effort of providing a solid theoretical understanding of the behaviors and regularities present in sociopolitical dynamics. Here we present a reliability theory of polity processes with emphases on individual political dynamics of African countries. We found that the structural properties of polity failure rates successfully capture the risk of political vulnerability and instabilities in which 87.50%, 75%, 71.43%, and 0% of the countries with monotonically increasing, unimodal, U-shaped and monotonically decreasing polity failure rates, respectively, have high level of state fragility indices. The quasi-U-shape relationship between average polity duration and regime types corroborates historical precedents and explains the stability of the autocracies and democracies.Comment: 4 pages, 3 figures, 1 tabl

Active diffusion and microtubule-based transport oppose myosin forces to position organelles in cells.

Even distribution of peroxisomes (POs) and lipid droplets (LDs) is critical to their role in lipid and reactive oxygen species homeostasis. How even distribution is achieved remains elusive, but diffusive motion and directed motility may play a role. Here we show that in the fungus Ustilago maydis ∼95% of POs and LDs undergo diffusive motions. These movements require ATP and involve bidirectional early endosome motility, indicating that microtubule-associated membrane trafficking enhances diffusion of organelles. When early endosome transport is abolished, POs and LDs drift slowly towards the growing cell end. This pole-ward drift is facilitated by anterograde delivery of secretory cargo to the cell tip by myosin-5. Modelling reveals that microtubule-based directed transport and active diffusion support distribution, mobility and mixing of POs. In mammalian COS-7 cells, microtubules and F-actin also counteract each other to distribute POs. This highlights the importance of opposing cytoskeletal forces in organelle positioning in eukaryotes.We thank Dr G. Dagdas, Dr S. Kilaru, Mr M. Schlick and Mrs T. Schrader for technical support. We thank Professor N.J. Talbot for helpful comments on the manuscript. This work was supported by the Biotechnology & Biological Sciences Research Council (BB/J009903/1 to G.S.). S.C.G. was supported by a fellowship from the Portuguese Foundation for Science and Technology (FCT) (SFRH/BD/73532/2010). J.M. is supported by a Wellcome Trust Institutional Strategic Support Award (WT097835MF)

Citizens, bribery and the propensity to protest

It is widely assumed that the more one experiences corruption the more likely one is to want to protest about it. Yet empirical evidence illustrating this is thin on the ground. This paper fills that gap by focusing on the extent to which self-reported experience of bribery affects the willingness to engage in protests against corruption in Africa. We find that the more one experiences bribery the more one is likely to support anti-corruption protests. A further unexpected finding is that the personal experience of corruption also increases the willingness to rely on bribes to solve public administration problems