Reducing distortions in international commodity markets : an agenda for multilateral cooperation

Global commodity markets are affected by a variety of government policies that may expand or lower overall supply and as a result affect world prices for the specific products concerned. Market failures and market structures (market power along the value chain) also affect supply. This paper briefly reviews a number of factors that may distort international commodity markets with a view to identifying elements of an agenda for multilateral cooperation to reduce such distortions. Much of the policy agenda that arises is domestic and requires action by national governments. But numerous policies -- or absence of policy -- generate international spillovers that call for the negotiation of international policy disciplines. Independent of whether distortions are local or international in scope, the complexity of prevailing market structures and their impacts on efficiency call for much greater monitoring and analysis by the international community.Markets and Market Access,Economic Theory&Research,Emerging Markets,Access to Markets,Free Trade

Moment and SDP relaxation techniques for smooth approximations of problems involving nonlinear differential equations

Combining recent moment and sparse semidefinite programming (SDP) relaxation techniques, we propose an approach to find smooth approximations for solutions of problems involving nonlinear differential equations. Given a system of nonlinear differential equations, we apply a technique based on finite differences and sparse SDP relaxations for polynomial optimization problems (POP) to obtain a discrete approximation of its solution. In a second step we apply maximum entropy estimation (using moments of a Borel measure associated with the discrete solution) to obtain a smooth closed-form approximation. The approach is illustrated on a variety of linear and nonlinear ordinary differential equations (ODE), partial differential equations (PDE) and optimal control problems (OCP), and preliminary numerical results are reported

Conclude Doha : it matters !

The Doha Round must be concluded not because it will produce dramatic liberalization but because it will create greater security of market access. Its conclusion would strengthen, symbolically and substantively, the WTO’s valuable role in restraining protectionism in the current downturn. What is on the table would constrain the scope for tariff protection in all goods, ban agricultural export subsidies in the industrial countries and sharply reduce the scope for distorting domestic support - by 70 per cent in the EU and 60 per cent in the US. Average farm tariffs that exporters face would fall to 12 per cent (from 14.5 per cent) and the tariffs on exports of manufactures to less than 2.5 per cent (from about 3 per cent). There are also environmental benefits to be captured, in particular disciplining the use of subsidies that encourage over-fishing and lowering tariffs on technologies that can help mitigate global warming. An agreement to facilitate trade by cutting red tape will further expand trade opportunities. Greater market access for the least-developed countries will result from the"duty free and quota free"proposal and their ability to take advantage of new opportunities will be enhanced by the Doha-related"aid for trade"initiative. Finally, concluding Doha would create space for multilateral cooperation on critical policy matters that lie outside the Doha Agenda, most urgently the trade policy implications of climate change mitigation.Economic Theory&Research,Free Trade,Emerging Markets,Trade Policy,Trade Law

Polychromatic Colorings on the Hypercube

Given a subgraph G of the hypercube Q_n, a coloring of the edges of Q_n such that every embedding of G contains an edge of every color is called a G-polychromatic coloring. The maximum number of colors with which it is possible to G-polychromatically color the edges of any hypercube is called the polychromatic number of G. To determine polychromatic numbers, it is only necessary to consider a structured class of colorings, which we call simple. The main tool for finding upper bounds on polychromatic numbers is to translate the question of polychromatically coloring the hypercube so every embedding of a graph G contains every color into a question of coloring the 2-dimensional grid so that every so-called shape sequence corresponding to G contains every color. After surveying the tools for finding polychromatic numbers, we apply these techniques to find polychromatic numbers of a class of graphs called punctured hypercubes. We also consider the problem of finding polychromatic numbers in the setting where larger subcubes of the hypercube are colored. We exhibit two new constructions which show that this problem is not a straightforward generalization of the edge coloring problem.Comment: 24 page

Polychromatic Colorings on the Integers

We show that for any set $S\subseteq \mathbb{Z}$, $|S|=4$ there exists a 3-coloring of $\mathbb{Z}$ in which every translate of $S$ receives all three colors. This implies that $S$ has a codensity of at most $1/3$, proving a conjecture of Newman [D. J. Newman, Complements of finite sets of integers, Michigan Math. J. 14 (1967) 481--486]. We also consider related questions in $\mathbb{Z}^d$, $d\geq 2$.Comment: 16 pages, improved presentatio

Dramaturgie et analyse dramaturgique

L’article propose : 1) une étude de l’évolution sémantique (et historique) du concept de dramaturgie, du concepteur originel de l’oeuvre dramatique (le dramatourgos) à celui qui en entreprend désormais l’étude en vue de son passage à la scène (der Dramaturg); 2) un examen de la notion contemporaine de dramaturgie, née avec G. E. Lessing; une notion qui entre aujourd’hui à part entière, en tant qu’étude prospective préalable et/ou d’accompagnement, dans le champ pragmatique du travail théâtral, dans l’élaboration à la fois conceptuelle et concrète de la mise en scène; 3) une recension des diverses figures du dramaturge, proche collaborateur du metteur en scène et qui tisse avec lui le texte spectaculaire qui sera proposé à l’interprétation du spectateur.This article proposes: 1) to study the semantic (and historical) evolution of the concept of dramaturgy, from the original creator of a dramatic work (the dramatourgos) to the one who studies it in order to bring it to life on the stage (der Dramaturg); 2) to examine the contemporary notion of dramaturgy, created by G. E. Lessing; a notion which has entered by its own right in the pragmatic field of theater work, as a prospective preparatory study, both in the conceptual preparation of the mise-en-scène and in its concrete realization; 3) to identify the different aspects of the dramaturg who, as a close collaborator of the stage director, brings together the various threads of the stage play before it is presented to the spectator for his or her interpretation

Trends and inequalities in laryngeal cancer survival in men and women: England and Wales 1991-2006.

Laryngeal cancer in men is a relatively common malignancy, with a marked socioeconomic gradient in survival between affluent and deprived patients. Cancer of the larynx in women is rare. Survival tends to lower than for men, and little is known about the association between deprivation and survival in women with laryngeal cancer. This paper explores the trends and socio-economic inequalities in laryngeal cancer survival in women, with comparison to men. We examined relative survival among men and women diagnosed with laryngeal cancer in England and Wales during 1991-2006, followed up to 31 December 2007. We estimated the difference in survival between the most deprived and most affluent groups (the 'deprivation gap') at one and five years after diagnosis, for each sex, anatomical subsite and calendar period. Five year survival for all laryngeal cancers combined was up to 8% lower in women than in men. This difference is only partially explained by the differential distribution of anatomical subsites in men and women. Disparities in survival between men and women were also present within specific subsites. In contrast to men, there was little evidence of a consistent deprivation gap in survival for women at any of the anatomical subsites. The stark socioeconomic inequalities in laryngeal cancer survival in men do not appear to be replicated in women. The origins of the socio-economic inequalities in survival among men, and the disparities in survival between men and women at specific tumour subsites remains unclear