Euclidean random matrix theory: low-frequency non-analyticities and Rayleigh scattering

By calculating all terms of the high-density expansion of the euclidean random matrix theory (up to second-order in the inverse density) for the vibrational spectrum of a topologically disordered system we show that the low-frequency behavior of the self energy is given by $\Sigma(k,z)\propto k^2z^{d/2}$ and not $\Sigma(k,z)\propto k^2z^{(d-2)/2}$, as claimed previously. This implies the presence of Rayleigh scattering and long-time tails of the velocity autocorrelation function of the analogous diffusion problem of the form $Z(t)\propto t^{(d+2)/2}$.Comment: 27 page

Modelling the impact of policies to reduce environmental impacts in the New Zealand dairy sector

Agriculture remains a major sector of the New Zealand economy, with the vast majority of farm and food production exported. The accelerating intensification of farming in New Zealand over recent decades raises concern over the current sustainability of New Zealand farming, and whether it can remain so in the future. In this study, we focus on the impacts of policies to reduce environmental impacts of dairy farming, with a particular focus on nitrogen pollution and greenhouse gases (GHG) emissions. We use a modified version of the Global Trade Analysis Project (GTAP) model and database, with improved specification of the agricultural sector and land-use. We augment the model with environmental indicators for New Zealand, including nitrogen balances and GHG emissions. We simulate a range of scenarios involving reductions in fertiliser use and stocking rates on dairy farms, from an updated 2010 database. In particular, we consider seven scenarios, with the objective of exploring reductions in the dairy stocking rate and the application of nitrogenous fertiliser to dairy farms to target reductions in the dairy sector’s nitrogen balance of 10%, 20% and 30%. Reducing fertiliser use and stocking rates are two of the approaches that dairy farmers can take in order to reduce their emissions of nitrogen and GHGs. Our results suggest that the nitrogen balance could be reduced by 10% with a 16% cut in nitrogenous fertiliser and a 5% fall in the stocking rate. Reducing fertiliser use and stocking rate by 31% and 11% respectively could result in a 20% cut to the dairy sector’s nitrogen balance. To achieve a 30% reduction in the nitrogen balance, our results suggest that the cut back in fertiliser use would need to be 45%, with the stocking rate reduced by 19%. Across these scenarios, our results indicate that value added in the dairy farm sector could fall by between 2% and 13%, while export earnings from dairy products may fall by between US$269 million and US$1,145 million

Tariff Rate Quotas and New Zealand’s Meat and Dairy Trade

The tariff rate quota (TRQ) system was formalised in the Uruguay Round with the aim of maintaining and improving market access for agricultural products. Under this system, a lower tariff rate is applied to imports up to the quota limit, with a higher (and often prohibitive) tariff rate levied on products imported beyond this quota. However, the success of the TRQ system has been limited, with dairy and meat products in particular still facing relatively high barriers to international trade. In this paper, we examine the impact of the TRQ system on New Zealand’s meat and dairy trade. We draw together theoretical and empirical insights and present preliminary findings arising from interviews with key stakeholders. In particular, we examine whether the TRQ system has achieved its objectives from the perspective of the dairy and meat sectors in New Zealand and we analyse problems that appear to exist with the system. We also examine implications of reform of the TRQ system, including lower in- and over-quota rates, increased quota limits and more transparent and efficient administration methods.Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Environmental Economics and Policy, Farm Management, International Relations/Trade, Land Economics/Use, Livestock Production/Industries,

DAnkrd49 and Bdbt act via casein kinase Iε to regulate planar polarity in Drosophila

The core planar polarity proteins are essential mediators of tissue morphogenesis, controlling both the polarised production of cellular structures and polarised tissue movements. During development the core proteins promote planar polarisation by becoming asymmetrically localised to opposite cell edges within epithelial tissues, forming intercellular protein complexes that coordinate polarity between adjacent cells. Here we describe a novel protein complex that regulates the asymmetric localisation of the core proteins in the Drosophila pupal wing. DAnkrd49 (an ankyrin repeat protein) and Bride of Doubletime (Bdbt, a non-canonical FK506 binding protein family member) physically interact, and regulate each other's levels in vivo. Loss of either protein results in a reduction in core protein asymmetry and disruption of the placement of trichomes at the distal edge of pupal wing cells. Post-translational modifications are thought to be important for the regulation of core protein behaviour and their sorting to opposite cell edges. Consistent with this, we find that loss of DAnkrd49 or Bdbt leads to reduced phosphorylation of the core protein Dishevelled and to decreased Dishevelled levels both at cell junctions and in the cytoplasm. Bdbt has previously been shown to regulate activity of the kinase Discs Overgrown (Dco, also known as Doubletime or Casein Kinase Iε), and Dco itself has been implicated in regulating planar polarity by phosphorylating Dsh as well as the core protein Strabismus. We demonstrate that DAnkrd49 and Bdbt act as dominant suppressors of Dco activity. These findings support a model whereby Bdbt and DAnkrd49 act together to modulate the activity of Dco during planar polarity establishment

International trade negotiations and the trans-border movement of people: A review of the literature

We review the international and New Zealand literatures on the two-way interaction between international migration and agreements designed to enhance cross-border trade or investment. Benefits and costs of migration, to the extent that these may feature in trade and migration negotiations, are discussed. While trade and migration can be substitutes in some contexts, they will be complements in other contexts. Liberalisation of services and the movement of people are likely to offer much more significant gains than liberalisation of remaining barriers to goods trade. Significant scope for liberalisation under GATS mode 4 (the movement of natural persons) may remain. However, temporary migration is already promoted on a unilateral and bilateral basis within immigration policy frameworks that may provide greater flexibility than GATS mode 4. With respect to both trade and migration, the more diverse the exchanging countries are, the greater the economic benefits tend to be. However, greater diversity may also imply greater social costs. This paradox of diversity needs to be addressed through appropriate social policies accompanying enhanced temporary and permanent migration

Challenges and Opportunities for Trade and Financial Integration in Asia and the Pacific

While it is commonly accepted that multilateral liberalization will bring the greatest global gains from liberalization, regional agreements may be much more feasible in the short term. The dictum from the traditional trade theory on the superiority of unilaterally applied free trade for a small economy under perfect competition is universally accepted but rarely applied to policymaking. Reasons for this are many, ranging from using trade policy for non-economic objectives (e.g., employment), to circumstances in an actual economy and markets being different from those of the economic model (e.g. existence of economies of scale, imperfect competition or imperfect information). Nevertheless many countries have embraced the advantages of open trade regimes and have pursued liberal trade unilaterally or more often through membership in the multilateral trading system, the General Agreement on Tariffs and Trade (GATT) and the World Trade Organization (WTO). On the other hand, both trade theory and the international trading rules allow for the discriminatory trade policies in the forms of preferential or regional trade agreements.trade policies, GATT, WTO, regional, agreement, goods, Asia, Pacific, GDP

A Dual Function for Prickle in Regulating Frizzled Stability during Feedback-Dependent Amplification of Planar Polarity

The core planar polarity pathway coordinates epithelial cell polarity during animal development, and loss of its activity gives rise to a range of defects, from aberrant morphogenetic cell movements to failure to correctly orient structures, such as hairs and cilia. The core pathway functions via a mechanism involving segregation of its protein components to opposite cells ends, where they form asymmetric intracellular complexes that couple cell-cell polarity. This segregation is a self-organizing process driven by feedback interactions between the core proteins themselves. Despite intense efforts, the molecular pathways underlying feedback have proven difficult to elucidate using conventional genetic approaches. Here we investigate core protein function during planar polarization of the Drosophila wing by combining quantitative measurements of protein dynamics with loss-of-function genetics, mosaic analysis, and temporal control of gene expression. Focusing on the key core protein Frizzled, we show that its stable junctional localization is promoted by the core proteins Strabismus, Dishevelled, Prickle, and Diego. In particular, we show that the stabilizing function of Prickle on Frizzled requires Prickle activity in neighboring cells. Conversely, Prickle in the same cell has a destabilizing effect on Frizzled. This destabilizing activity is dependent on the presence of Dishevelled and blocked in the absence of Dynamin and Rab5 activity, suggesting an endocytic mechanism. Overall, our approach reveals for the first time essential in vivo stabilizing and destabilizing interactions of the core proteins required for self-organization of planar polarity

Assessing Socioeconomic Impacts of Transport Infrastructure Projects in the Greater Mekong Subregion

This study attempts to quantify the links between infrastructure investment and poverty reduction using a multi-region general equilibrium model, supplemented with household survey data for the Greater Mekong Subregion (GMS). Infrastructure investment is an important step in economic development, with improvements in transportation infrastructure boosting economic opportunities throughout the region, for example by significantly reducing travel times and costs. In this study, we concentrate on quantifying the effects of some of the key linkages between upgraded infrastructure, economic growth, and poverty reduction. We model the impact of both reducing transport costs and improving trade facilitation in the GMS. Our findings suggest strong gains to the GMS countries as a result of infrastructure development and trade facilitation with national poverty reduced throughout the region. However, the impact on various segments of these populations differs, depending in part on factor returns.greater mekong subregion; poverty reduction; infrastructure investment

Molecular mechanisms mediating asymmetric subcellular localisation of the core planar polarity pathway proteins

Planar polarity refers to cellular polarity in an orthogonal plane to apicobasal polarity, and is seen across scales from molecular distributions of proteins to tissue patterning. In many contexts it is regulated by the evolutionarily conserved ‘core' planar polarity pathway that is essential for normal organismal development. Core planar polarity pathway components form asymmetric intercellular complexes that communicate polarity between neighbouring cells and direct polarised cell behaviours and the formation of polarised structures. The core planar polarity pathway consists of six structurally different proteins. In the fruitfly Drosophila melanogaster, where the pathway is best characterised, an intercellular homodimer of the seven-pass transmembrane protein Flamingo interacts on one side of the cell junction with the seven-pass transmembrane protein Frizzled, and on the other side with the four-pass transmembrane protein Strabismus. The cytoplasmic proteins Diego and Dishevelled are co-localised with Frizzled, and Prickle co-localises with Strabismus. Between these six components there are myriad possible molecular interactions, which could stabilise or destabilise the intercellular complexes and lead to their sorting into polarised distributions within cells. Post-translational modifications are key regulators of molecular interactions between proteins. Several post-translational modifications of core proteins have been reported to be of functional significance, in particular phosphorylation and ubiquitination. In this review, we discuss the molecular control of planar polarity and the molecular ecology of the core planar polarity intercellular complexes. Furthermore, we highlight the importance of understanding the spatial control of post-translational modifications in the establishment of planar polarity