The extended gaussian ensemble and metastabilities in the Blume-Capel model

The Blume-Capel model with infinite-range interactions presents analytical solutions in both canonical and microcanonical ensembles and therefore, its phase diagram is known in both ensembles. This model exhibits nonequivalent solutions and the microcanonical thermodynamical features present peculiar behaviors like nonconcave entropy, negative specific heat, and a jump in the thermodynamical temperature. Examples of nonequivalent ensembles are in general related to systems with long-range interactions that undergo canonical first-order phase transitions. Recently, the extended gaussian ensemble (EGE) solution was obtained for this model. The gaussian ensemble and its extended version can be considered as a regularization of the microcanonical ensemble. They are known to play the role of an interpolating ensemble between the microcanonical and the canonical ones. Here, we explicitly show how the microcanonical energy equilibrium states related to the metastable and unstable canonical solutions for the Blume-Capel model are recovered from EGE, which presents a concave "extended" entropy as a function of energy.Comment: 6 pages, 5 eps figures. Presented at the XI Latin American Workshop on Nonlinear Phenomena, October 05-09 (2009), B\'uzios (RJ), Brazil. To appear in JPC

A Genomic Signature and the Identification of New Sporulation Genes

Bacterial endospores are the most resistant cell type known to humans, as they are able to withstand extremes of temperature, pressure, chemical injury, and time. They are also of interest because the endospore is the infective particle in a variety of human and livestock diseases. Endosporulation is characterized by the morphogenesis of an endospore within a mother cell. Based on the genes known to be involved in endosporulation in the model organism Bacillus subtilis, a conserved core of about 100 genes was derived, representing the minimal machinery for endosporulation. The core was used to define a genomic signature of about 50 genes that are able to distinguish endospore-forming organisms, based on complete genome sequences, and we show this 50-gene signature is robust against phylogenetic proximity and other artifacts. This signature includes previously uncharacterized genes that we can now show are important for sporulation in B. subtilis and/or are under developmental control, thus further validating this genomic signature. We also predict that a series of polyextremophylic organisms, as well as several gut bacteria, are able to form endospores, and we identified 3 new loci essential for sporulation in B. subtilis: ytaF, ylmC, and ylzA. In all, the results support the view that endosporulation likely evolved once, at the base of the Firmicutes phylum, and is unrelated to other bacterial cell differentiation programs and that this involved the evolution of new genes and functions, as well as the cooption of ancestral, housekeeping functions.FCT grant: (PEst-OE/EQB/LA0004/2011), FCT Ph.D. fellowship: (SFRH/BPD/36328/2007), FCT postdoc fellowship: (SFRH/BPD/65605/2009), Instituto Gulbenkian de Ciência research fellowship

Emissão de óxido nitroso derivada do cultivo de feijoeiro comum (3ª safra) seguido de milho em latossolo de cerrado.

o presente estudo objetivou quantificar a emissão do óxido nitroso do solo sob a cultura do feijoeiro comum irrigado (terceira safra) e sob milho (safra de verão) em plantio direto, em Santo Antônio de Goiás, GO

Fator de emissão para óxido nitroso do solo cultivado com arroz de terras altas em plantio direto.

O objetivo do presente estudo foi o de estimar a emissão de N2O de um solo de cerrado sob a cultura do arroz de terras altas em duas safras consecutivas (2005/06 e 2006/07)

Estimates of genetic parameters for physic nut traits based in the germplasm two years evaluation.

Apesar do crescente interesse no plantio do pinhão manso, os esforços de melhoramento ainda estão em seu início. Nesse contexto, um importante recurso recentemente estabelecido visando a futuros trabalhos de melhoramento foi a montagem de um banco de germoplasma com cerca de 200 acessos. O objetivo deste estudo foi estimar parâmetros genéticos, coeficientes de repetibilidade e correlações genéticas entre sete características, mensuradas em 110 acessos (famílias de meios-irmãos) desse banco de germoplasma em diferentes estágios de desenvolvimento. Os resultados demonstram que valores elevados de variância genética aditiva foram encontrados apenas para produção e altura e a existência de baixa variação ambiental (tanto de natureza temporária quanto permanente) entre parcelas dentro de blocos. Dado os altos valores de repetibilidade encontrados para todas as características, em média três mensurações são necessárias para se predizer, acurada e eficientemente, o real valor de melhoramento de um indivíduo. Baseado nos resultados de correlações genéticas, esforços de melhoramento devem inicialmente ser usados para se identificar árvores de elevado diâmetro de caule, elevado número de ramos e volume de copa, de modo a aumentar as chances de se encontrar árvores excepcionalmente produtivas

Fator de emissão de óxido nitroso derivada de culturas anuais em plantio direto sob latossolo de cerrado.

o presente estudo objetivou quantificar a emissão do óxido nitroso do solo sob a cultura do feijoeiro comum irrigado (terceira safra) e sob milho (safra de verão), em plantio direto em Santo Antônio de Goiás GO

Beverage quality of most cultivated Coffea canephora clones in the Western Amazon.

Most of the Western Amazon coffee production is made from growing unregistered clones, selected by the coffee growers themselves. The aim of this study is to evaluate the sensory profile and genetic diversity of the most cultivated Coffea canephora clones in the Western Amazon. Coffee samples at cherry stage of the clones 03, 05, 08, 25 and 66 were collected at eight municipalities in the main coffee growing zones, with altitudes ranging from 86 to 381 meters. Beverage quality was evaluated according to the Robusta Cupping Protocols and estimates of the genotype × environment interaction (GE) were made interpreting non-parametric and multivariate methods. The GE interaction was significant and the genetic component was also important to the expression of beverage quality (h2 =82,23). The clones 25 and 05 have good attributes and mean score near 80 points. Sweetness was the sensory descriptor with the greatest impact on beverage quality of these two clones. Harshness was the descriptor that had the greatest negative impact on beverage quality of clone 66. The clones had complexities that differed and that were not necessarily associated with greater beverage quality. Despite the differences in their beverage attributes, these clones that are grown for their high productivity presented low genetic diversity of the beverage quality

The nature of the dense core population in the pipe nebula: core and cloud kinematics from C18O observations

We present molecular-line observations of 94 dark cloud cores identified in the Pipe nebula through near-IR extinction mapping. Using the Arizona Radio Observatory 12m telescope, we obtained spectra of these cores in the J=1-0 transition of C18O. We use the measured core parameters, i.e., antenna temperature, linewidth, radial velocity, radius and mass, to explore the internal kinematics of these cores as well as their radial motions through the larger molecular cloud. We find that the vast majority of the dark extinction cores are true cloud cores rather than the superposition of unrelated filaments. While we identify no significant correlations between the core's internal gas motions and the cores' other physical parameters, we identify spatially correlated radial velocity variations that outline two main kinematic components of the cloud. The largest is a 15pc long filament that is surprisingly narrow both in spatial dimensions and in radial velocity. Beginning in the Stem of the Pipe, this filament displays uniformly small C18O linewidths (dv~0.4kms-1) as well as core to core motions only slightly in excess of the gas sound speed. The second component outlines what appears to be part of a large (2pc; 1000 solar mass) ring-like structure. Cores associated with this component display both larger linewidths and core to core motions than in the main cloud. The Pipe Molecular Ring may represent a primordial structure related to the formation of this cloud.Comment: Accepted to ApJ. 14 pages, 11 figures. Complete table at end of documen