Analysis the f0(980)f_0(980) and a0(980)a_0(980) mesons as four-quark states with the QCD sum rules

In this article, we take the point of view that the scalar mesons $f_0(980)$ and $a_0(980)$ are diquark-antidiquark states $(qq)_{\bar{3}}(\bar{q}\bar{q})_3$, and devote to determine their masses in the framework of the QCD sum rules approach with the interpolating currents constructed from scalar-scalar type and pseudoscalar-pseudoscalar type diquark pairs respectively. The numerical results indicate that the scalar mesons $f_0(980)$ and $a_0(980)$ may have two possible diquark-antidiquark substructures.Comment: 8 pages, 1 figure, revised versio

Getting real about food prices

The 2008 price spike in world grain prices had serious impacts on food security and poverty but analysts have consistently described these real food prices as low in historical terms. The inconsistency between the severity of the food crisis and low real prices results from the use of advanced and global economy price indices to calculate real prices. This ignores the high share of food in poor people’s expenditures and indirect effects of income growth on expenditure patterns of rich and poor consumers. Poor consumers have not experienced the same falls in real food prices as those with growing incomes and are more vulnerable to price shocks. As high and fluctuating international grain prices appear to be a feature of the current world economy, food price and policy analysis must recognise this, and develop and use different price indices that take account of differences between consumer groups

Relative importance of fertiliser addition to plants and exclusion of predators for aphid growth in the field

Herbivore dynamics and community structure are influenced both by plant quality and the actions of natural enemies. A factorial experiment manipulating both higher and lower trophic levels was designed to explore the determinants of colony growth of the aphid Aphis jacobaeae, a specialist herbivore on ragwort Senecio jacobaea. Potential plant quality was manipulated by regular addition of NPK-fertiliser and predator pressure was reduced by interception traps; the experiment was carried out at two sites. The size and persistence of aphid colonies were measured. Fertiliser addition affected plant growth in only one site, but never had a measurable effect on aphid colony growth. In both habitats the action of insect predators dominated, imposing strong and negative effects on aphid colony performance. Ants were left unmanipulated in both sites and their performance on the aphid colonies did not significantly differ between sites or between treatments. Our results suggest that, at least for aphid herbivores on S. jacobaea, the action of generalist insect predators appears to be the dominant factor affecting colony performance and can under certain conditions even improve plant productivit

Food systems and diets: Facing the challenges of the 21st century

The world is facing a nutrition crisis: approximately three billion people from every one of the world’s 193 countries have low-quality diets. Over the next 20 years, multiple forms of malnutrition will pose increasingly serious threats to global health. Population growth combined with climate change will place increasing stress on food systems, particularly in Africa and Asia where there will be an additional two billion people by 2050. At the same time, rapidly increasing urbanization, particularly in these two regions, will affect hunger and nutrition in complex ways – both positively and negatively. Unless policy makers apply the brakes on overweight, obesity and diet-related disease and accelerate efforts to reduce undernutrition, everyone will pay a heavy price: death, disease, economic losses and degradation of the environment. A response, equivalent to that marshalled to tackle HIV/AIDS, malaria and smoking is needed to meet these challenges. Around the world, coordinated action needs to be accompanied by fundamental shifts in our understanding and in our policy actions. Much more emphasis must be given to positioning agricultural growth as a way to improve diet quality, rather than merely delivering sufficient calories. Food systems need to be repositioned from just supplying food to providing high-quality diets for all. This will require policy initiatives far beyond agriculture to encompass trade, the environment and health, which harness the power of the private sector and empower consumers to demand better diets. This report is a call to action for world leaders and their governments. Leadership and commitment will be essential in driving forward the decisions set out in this report and in delivering the necessary priority actions to reshape the global food system

Exposure to the neonicotinoid imidacloprid disrupts sex allocation cue use during superparasitism in the parasitoid wasp Nasonia vitripennis

N.C., J.G., and D.M.S. were funded by Natural Environment Research Council (NERC) grant (NE/J024481/1). P.R.W. was funded by a University of Stirling Impact Fellowship.1. Neonicotinoid insecticides are potent neurotoxins of significant economic importance. However, it is clear that their use can adversely impact beneficial insects in the environment, even at low, sub-lethal doses. 2. It has recently been shown that the neonicotinoid imidacloprid disrupts adaptive sex allocation in the parasitoid wasp Nasonia vitripennis (Walker) by limiting their ability to respond to the presence of other females on oviposition patches. In the present study, that work was extended to explore whether sex allocation when superparasitising – laying eggs on a host that has already been parasitised – is also disrupted by imidacloprid. 3. Under superparasitism, sex allocation theory predicts that females should vary their offspring sex ratio in relation to their relative clutch size. It was found that sex allocation under superparasitism in Nasonia is disrupted in a dose-dependent manner, with exposed females producing more daughters. 4. Importantly, imidacloprid does not appear to influence the ability of females to estimate the number of eggs already present on a host, suggesting a disassociation between the sex ratio and clutch size cues. 5. The present work highlights the fitness costs to beneficial insects of exposure to neonicotinoids, but also provides clues as to how female Nasonia use information when allocating sex.Publisher PDFPeer reviewe