(de)constructing The Political Agenda Of Control Over Pesticides In Brazil

This article provides a history of the creation of Brazil's federal law governing pesticide production, commerce and use. It begins with initiatives by environmental movements that led States to adopt pesticide control laws, thus helping put the issue on the federal agenda. It discusses major innovations and limitations to the law's enforcement and identifies the main attempts to deconstruct it, through bills aimed at suppressing the powers of public authorities to reduce adverse effects of pesticides on human health and the environment.19321323

Chiral Perturbation Theory, the 1/Nc{1/N_c} expansion and Regge behaviour determine the structure of the lightest scalar meson

The leading $1/N_c$ behaviour of Unitarised Chiral Perturbation Theory distinguishes the nature of the $\rho$ and the $\sigma$. At one loop order the $\rho$ is a ${\bar q}q$ meson, while the $\sigma$ is not. However, semi-local duality between resonances and Regge behaviour cannot be satisfied for larger $N_c$, if such a distinction holds. While the $\sigma$ at $N_c=3$ is inevitably dominated by its di-pion component, Unitarised Chiral Perturbation Theory beyond one loop order reveals that as $N_c$ increases above 6-8, the $\sigma$ has a sub-dominant ${\bar q}q$ fraction up at 1.2 GeV. Remarkably this ensures semi-local duality is fulfilled for the range of $N_c \lesssim 15$, where the unitarisation procedure adopted applies.Comment: 22 pages, 8 figures. Version to be published in Physical Review

Leading- and next-to-leading-order lateral Casimir force on corrugated surfaces

We derive explicit analytic expressions for the lateral force for two different configurations with corrugations, parallel plates and concentric cylinders. By making use of the multiple scattering formalism, we calculate the force for a scalar field under the influence of a delta-function potential that has sinusoidal dependence in one direction simulating the corrugations. By making a perturbative expansion in the amplitude of the corrugation we find the leading order for the corrugated concentric cylinders and the next-to-leading order for the corrugated parallel plates.Comment: 6 pages. Seventh Alexander Friedmann International Seminar on Gravitation and Cosmolog

Casimir interaction between plane and spherical metallic surfaces

We give an exact series expansion of the Casimir force between plane and spherical metallic surfaces in the non trivial situation where the sphere radius $R$, the plane-sphere distance $L$ and the plasma wavelength $\lambda_\P$ have arbitrary relative values. We then present numerical evaluation of this expansion for not too small values of $L/R$. For metallic nanospheres where $R, L$ and $\lambda_\P$ have comparable values, we interpret our results in terms of a correlation between the effects of geometry beyond the proximity force approximation (PFA) and of finite reflectivity due to material properties. We also discuss the interest of our results for the current Casimir experiments performed with spheres of large radius $R\gg L$.Comment: 4 pages, new presentation (highlighting the novelty of the results) and added references. To appear in Physical Review Letter

MeV measurements of gamma-ray bursts by CGRO-COMPTEL

Since the launch of the Compton Gamma-Ray Observatory in April 1991, the imaging COMPTEL telescope has accumulated positions and 0.75–30 MeV spectra of more than thirty gamma-ray bursts within its ∼π sr field of view. In an ongoing collaboration with BACODINE/GCN, COMPTEL positions are relayed to a global network of multiwavelength observers in near real time (∼10 minutes). Here we summarize the MeV properties, and present spatial, spectral, and temporal data for the latest of these events, GRB 970807. In concurrence with earlier SMM and current BATSE, OSSE, and EGRET measurements, COMPTEL data add to the accumulating evidence that GRB spectra do seem to have a characteristic shape: a peak (inE2F(E) ) around several hundred keV; and a power law above (spectral index 1.5–3.5) extending beyond the COMPTEL energy range

Structure of Light Scalar Mesons from D_s and D^0 Non-Leptonic Decays

Non-leptonic D meson decays may provide a reliable testbed for the multiquark interpretation of light scalar mesons. In this letter we consider D_s decay and show that a 4-quark f_0(980) meson could induce a decay pattern, which is forbidden for a q-qbar constituent structure. Experimental tests to probe such possibilities are within reach in the near future.Comment: 11 pages, 3 figures, minor changes. To appear in Phys. Lett.

Microbial diversity and metabolic networks in acid mine drainage habitats

Acid mine drainage (AMD) emplacements are low-complexity natural systems. Low-pH conditions appear to be the main factor underlying the limited diversity of the microbial populations thriving in these environments, although temperature, ionic composition, total organic carbon, and dissolved oxygen are also considered to significantly influence their microbial life. This natural reduction in diversity driven by extreme conditions was reflected in several studies on the microbial populations inhabiting the various micro-environments present in such ecosystems. Early studies based on the physiology of the autochthonous microbiota and the growing success of omics-based methodologies have enabled a better understanding of microbial ecology and function in low-pH mine outflows; however, complementary omics-derived data should be included to completely describe their microbial ecology. Furthermore, recent updates on the distribution of eukaryotes and archaea recovered through sterile filtering (herein referred to as filterable fraction) in these environments demand their inclusion in the microbial characterization of AMD systems. In this review, we present a complete overview of the bacterial, archaeal (including filterable fraction), and eukaryotic diversity in these ecosystems, and include a thorough depiction of the metabolism and element cycling in AMD habitats. We also review different metabolic network structures at the organismal level, which is necessary to disentangle the role of each member of the AMD communities described thus far