Balanço e análise da sustentabilidade energética na produção orgânica de hortaliças.

Os insumos e serviços utilizados na produção vegetal representam custo energético. Dependendo desses fatores e das produtividades obtidas, a conversão da produção em energia determinará a eficiência energética do sistema. A agricultura orgânica somente atingirá a missão de preservação ambiental se tiver comprovada sustentabilidade energética. Neste trabalho, objetivou-se caracterizar os balanços energéticos dos cultivos orgânicos e analisar sua sustentabilidade, em comparação aos sistemas convencionais. Monitoraram-se campos de produção de dez culturas, de 1991 a 2000 em Domingos Martins-ES. Os dados do sistema convencional foram obtidos pelas médias dos coeficientes técnicos da região. Quantificaram-se os coeficientes técnicos, convertendo suas grandezas físicas em equivalentes energéticos, expressos em kcal. O sistema orgânico gastou 4.571.159 kcal ha-1 e apresentou 12.696.712 kcal ha-1 de energia inserida na colheita, mostrando balanço médio de 2,78. Esse valor foi similar ao obtido no sistema convencional (1,93). As participações dos componentes nos gastos do sistema orgânico foram embalagem (35,8%), composto orgânico (17,2%), irrigação (12,6%), sementes/mudas (12,4%) e mão-de-obra (11,0%), serviços mecânicos (5,0%) e frete (4,5%). Se os custos com embalagens fossem eliminados, os gastos do sistema orgânico seriam reduzidos para 2.930.113 kcal ha-1, aumentando sua eficiência. A maioria dos cultivos orgânicos pode ser considerada sustentável em transformação de energia, com balanços superiores a 1,00 e produção média diária de 80.421 kcal ha-1 por dia, superior à necessidade mínima de 58.064 kcal ha-1

Phylogenetic relationships within Chamaecrista sect. Xerocalyx (Leguminosae, Caesalpinioideae) inferred from the cpDNA trnE-trnT intergenic spacer and nrDNA ITS sequences

Chamaecrista belongs to subtribe Cassiinae (Caesalpinioideae), and it comprises over 330 species, divided into six sections. The section Xerocalyx has been subjected to a profound taxonomic shuffling over the years. Therefore, we conducted a phylogenetic analysis using a cpDNA trnE-trnT intergenic spacer and nrDNA ITS/5.8S sequences from Cassiinae taxa, in an attempt to elucidate the relationships within this section from Chamaecrista. The tree topology was congruent between the two data sets studied in which the monophyly of the genus Chamaecrista was strongly supported. Our analyses reinforce that new sectional boundaries must be defined in the Chamaecrista genus, especially the inclusion of sections Caliciopsis and Xerocalyx in sect. Chamaecrista, considered here paraphyletic. The section Xerocalyx was strongly supported as monophyletic; however, the current data did not show C. ramosa (microphyllous) and C. desvauxii (macrophyllous) and their respective varieties in distinct clades, suggesting that speciation events are still ongoing in these specimens

Asteroseismology and Interferometry

Asteroseismology provides us with a unique opportunity to improve our understanding of stellar structure and evolution. Recent developments, including the first systematic studies of solar-like pulsators, have boosted the impact of this field of research within Astrophysics and have led to a significant increase in the size of the research community. In the present paper we start by reviewing the basic observational and theoretical properties of classical and solar-like pulsators and present results from some of the most recent and outstanding studies of these stars. We centre our review on those classes of pulsators for which interferometric studies are expected to provide a significant input. We discuss current limitations to asteroseismic studies, including difficulties in mode identification and in the accurate determination of global parameters of pulsating stars, and, after a brief review of those aspects of interferometry that are most relevant in this context, anticipate how interferometric observations may contribute to overcome these limitations. Moreover, we present results of recent pilot studies of pulsating stars involving both asteroseismic and interferometric constraints and look into the future, summarizing ongoing efforts concerning the development of future instruments and satellite missions which are expected to have an impact in this field of research.Comment: Version as published in The Astronomy and Astrophysics Review, Volume 14, Issue 3-4, pp. 217-36

Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets