Integrating resilience in South Asia

Communities in South Asia can strengthen their resilience by integrating disaster risk reduction, climate change adaptation and poverty reduction measures.published_or_final_versio

Ray helicity: a geometric invariant for multi-dimensional resonant wave conversion

For a multicomponent wave field propagating into a multidimensional conversion region, the rays are shown to be helical, in general. For a ray-based quantity to have a fundamental physical meaning it must be invariant under two groups of transformations: congruence transformations (which shuffle components of the multi-component wave field) and canonical transformations (which act on the ray phase space). It is shown that for conversion between two waves there is a new invariant not previously discussed: the intrinsic helicity of the ray

Classification of Standard Model Particles in E6E_6 Orbifold Grand Unified Theories

We classify the standard model fermions, which originate from bulk fields of the $\bf{27}$ or $\bar{\bf{27}}$ representation after orbifold breaking, in $E_6$ grand unified theories on 5 or 6-dimensional space-time, under the condition that $q$, $e^c$ and $u^c$ survive as zero modes.Comment: 24 pages, typos corrected, to appear in IJMP

Vortices on Hyperbolic Surfaces

It is shown that abelian Higgs vortices on a hyperbolic surface $M$ can be constructed geometrically from holomorphic maps $f:M \to N$, where $N$ is also a hyperbolic surface. The fields depend on $f$ and on the metrics of $M$ and $N$. The vortex centres are the ramification points, where the derivative of $f$ vanishes. The magnitude of the Higgs field measures the extent to which $f$ is locally an isometry. Witten's construction of vortices on the hyperbolic plane is rederived, and new examples of vortices on compact surfaces and on hyperbolic surfaces of revolution are obtained. The interpretation of these solutions as SO(3)-invariant, self-dual SU(2) Yang--Mills fields on $\R^4$ is also given.Comment: Revised version: new section on four-dimensional interpretation of hyperbolic vortices added

The Routine Use of Antibiotics to Promote Animal Growth Does Little to Benefit Protein Undernutrition in the Developing World

Some persons argue that the routine addition of antibiotics to animal feed will help alleviate protein undernutrition in developing countries by increasing meat production. In contrast, we estimate that, if all routine antibiotic use in animal feed were ceased, there would be negligible effects in these countries. Poultry and pork production are unlikely to decrease by more than 2%. Average daily protein supply would decrease by no more than 0.1 g per person (or 0.2% of total protein intake). Eliminating the routine use of in-feed antibiotics will improve human and animal health, by reducing the development and spread of antibiotic-resistant bacteri

Keeping the rhythm:light/dark cycles during postharvest storage preserve the tissue integrity and nutritional content of leafy plants

Background: The modular body structure of plants enables detached plant organs, such as postharvest fruits and vegetables, to maintain active responsiveness to environmental stimuli, including daily cycles of light and darkness. Twenty-four hour light/darkness cycles entrain plant circadian clock rhythms, which provide advantage to plants. Here, we tested whether green leafy vegetables gain longevity advantage by being stored under light/dark cycles designed to maintain biological rhythms. Results: Light/dark cycles during postharvest storage improved several aspects of plant tissue performance comparable to that provided by refrigeration. Tissue integrity, green coloration, and chlorophyll content were generally enhanced by cycling of light and darkness compared to constant light or darkness during storage. In addition, the levels of the phytonutrient glucosinolates in kale and cabbage remained at higher levels over time when the leaf tissue was stored under light/dark cycles. Conclusions: Maintenance of the daily cycling of light and dark periods during postharvest storage may slow the decline of plant tissues, such as green leafy vegetables, improving not only appearance but also the health value of the crops through the maintenance of chlorophyll and phytochemical content after harvest