On the absorption and production cross sections of KK and K∗K^*

We have computed the isospin and spin averaged cross sections of the processes $\pi K^*\to \rho K$ and $\rho K^*\to \pi K$, which are crucial in the determination of the abundances of $K^*$ and $K$ in heavy ion collisions. Improving previous calculations, we have considered several mechanisms which were missing, such as the exchange of axial and vector resonances ($K_1(1270)$, $K^*_2(1430)$, $h_1(1170)$, etc...) and also other processes such as $\pi K^*\to \omega K, \phi K$ and $\omega K^*,\,\phi K^*\to \pi K$. We find that some of these mechanisms give important contributions to the cross section. Our results also suggest that, in a hadron gas, $K^*$ production might be more important than its absorption

X(3872)X(3872) production and absorption in a hot hadron gas

We calculate the time evolution of the $X(3872)$ abundance in the hot hadron gas produced in the late stage of heavy ion collisions. We use effective field Lagrangians to obtain the production and dissociation cross sections of $X(3872)$. In this evaluation we include diagrams involving the anomalous couplings $\pi D^*\bar{D}^*$ and $X \bar{D}^{\ast} D^{\ast}$ and also the couplings of the $X(3872)$ with charged $D$ and $D^*$ mesons. With these new terms the $X(3872)$ interaction cross sections are much larger than those found in previous works. Using these cross sections as input in rate equations, we conclude that during the expansion and cooling of the hadronic gas, the number of $X(3872)$, originally produced at the end of the mixed QGP/hadron gas phase, is reduced by a factor of 4.Comment: 8 pages, 4 figure

Estudo agroecológico de agricultoras familiares de base ecológica no sudoeste da Amazônia (Outro Preto do Oeste, Rondônia).

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Agroforestry systems and food security among smallholder farmers of the Brazilian Amazon: a strategy for environmental global crisis.

The Amazon is known for its environmental importance for the climatic equilibrium, for its abundance and richness in biodiversity and its preservation is important to reduce global heating. Nevertheless, little research has analysed the possible positive role of the local farm population for environmental conservation. The paper investigates the possibility to conciliate the environmental conservation with the small farming expansion in the Amazon, to build agrobiodiversity, and at the same time improve food security. This social practice consequently would contribute to the reduction of deforestation and could thus falsify the old diagnosis of incriminating the poor farmers for forest and soil destruction. The study was conducted by the Associação de Produtores Alternativos, localized in territory of Ouro Preto d? Oeste, Rondônia, in the Southwest of the Amazon. The study documented a number of forest preservation and agroecological methods used and concludes that institutional support to strengthening of social organization and local sustainable development projects is fundamental for the consolidation and amplification of the ecological experiences in the Amazon