On Lorentz violation in e− ⁣ ⁣+ ⁣e+ ⁣→ ⁣μ− ⁣ ⁣+ ⁣μ+e^{-}\!\!+\!e^{+}\!\rightarrow\!\mu^{-}\!\!+\!\mu^{+} scattering at finite temperature

Small violation of Lorentz and CPT symmetries may emerge in models unifying gravity with other forces of nature. An extension of the standard model with all possible terms that violate Lorentz and CPT symmetries are included. Here a CPT-even non-minimal coupling term is added to the covariant derivative. This leads to a new interaction term that breaks the Lorentz symmetry. Our main objective is to calculate the cross section for the $e^{-}\!\!+\!e^{+}\!\rightarrow\!\mu^{-}\!\!+\!\mu^{+}$ scattering in order to investigate any violation of Lorentz and/or CPT symmetry at finite temperature. Thermo Field Dynamics formalism is used to consider finite temperature effects.Comment: 12 pages, 1 figure, accepted for publication in PL

Topology and Dynamics in Complex Networks: The Role of Edge Reciprocity

A key issue in complex systems regards the relationship between topology and dynamics. In this work, we use a recently introduced network property known as steering coefficient as a means to approach this issue with respect to different directed complex network systems under varying dynamics. Theoretical and real-world networks are considered, and the influences of reciprocity and average degree on the steering coefficient are quantified. A number of interesting results are reported that can assist the design of complex systems exhibiting larger or smaller relationships between topology and dynamics

Use of an enrichment analysis strategy to detect potential new drug targets in fungal genomes.

Fungi are a major class of pathogens in several animal and plant species, having a great agricultural, veterinary and medical importance. The search for anti-fungal drugs is an especially hard task due to the relative phylogenetic relatedness of fungi to their animal and vegetal hosts when compared with other classes of parasites, such as bacteria. This phylogenetic relatedness causes most of the potential druggable genes in fungi to be essential for both fungal and host genomes. This class of essential genes would tend to be observed at high frequencies in both groups. Essential genes specific of fungal species, however, would tend to be significantly more present in fungal genomes when compared with the frequency of the same gene in host genomes. In this study we used a software previously developed by our group named KOMODO (Kegg Orthology enrichMent analysis ? Online DetectiOn) that detects significantly under- or over-represented groups of homologous genes (as defined by KO groups) in one taxon when compared with the other. We used KOMODO to compare the Fungi and Eukarya taxa and identify significantly overrepresented KO groups in fungal genomes when compared with the eukaryotic background distribution of KO groups. Since each analysis using KOMODO tests thousands of hypotheses (one statistical test for each KO group surveyed), False Discovery Ratio approaches are implemented to control Type I error ratios and generate corrected q-values. Our software also displays the groups of biased homologous genes hierarchically classified according to their statistical significance and displayed into their proper biochemical roles as defined by Kegg Pathways into a dynamically generated webpage. The visual observation of the differentially represented genes adds an important source of information to help the biological comprehension of the phenomena behind the biased distributions detected. From the set of 2611 shared KO groups between Fungi and Eukarya taxa we found 88 of them to be significantly overrepresented in fungal genomes (q-value cutoff of <= 10e-5). These genes were then manually surveyed in scientific literature to verify if any of them was previously studied as essential and/or as a potential anti-fungal target. We found that some of these KO groups were already successfully evaluated as essential genes for fungal pathogenesis and/or survival, highlighting the ability of KOMODO to detect interesting gene candidates. More interestingly was the finding that most of the genes detected were never surveyed for their potential role in fungal survival. Additionally, several of these genes belong to essential pathways (such as sugar, amino acid and nucleotide metabolism), and could be considered as potential candidates for future studies to detect new essential genes for fungal survival. This study of case demonstrated the utility of KOMODO to detect both known and potentially new druggable genes by looking for enriched genes in fungal genomes when compared with other eukaryotes. As the number of complete genomes increase, we believe that a similar strategy could be used to survey other classes of eukaryotic parasites (such as protozoa, helminths and arthropods) for potential gene targets as well, making KOMODO a valuable tool to detect (and, consequently, prioritize) new drug targets in the figure of parasite-specific essential genes.X-MEETING 2011

Role-Playing in a Vaccination Debate Strengthens Student Scientific Debate Skills for Various Audiences

Students are surrounded by strongly-held viewpoints on scientific topics and frequently discuss news reports with their classmates. We developed the vaccination debate exercise to leverage this interest and develop core higher-order cognitive skills (HOCS), including, but not limited to, the ability to critique public media or primary research sources and create arguments for defending multiple viewpoints. Students prepared to debate different sides of the topic and then randomly assumed one of the roles: “Physician” (pro-vaccine), “Activist” (anti-vaccination), or “Parent-on-the-fence” (undecided). Students reported an increase in their abilities to discuss scientific topics with diverse audiences and an increased awareness of importance of examining Internet sources for credibility

Caracterização anatômica de frutos de genótipos de bananeira quanto ao despencamento.

As bananas são comercializadas em pencas ou buquês, geralmente com 4 a 9 frutos, sendo o despencamento dos frutos um dos principais problemas na comercialização, fazendo com que ocorra diminuição da aceitação dos consumidores e, consequentemente, diminuição do valor de mercado da fruta. Este despencamento dos frutos é uma desordem fisiológica pós-colheita associada com o amadurecimento