Evolving wormhole geometries within nonlinear electrodynamics

In this work, we explore the possibility of evolving (2+1) and (3+1)-dimensional wormhole spacetimes, conformally related to the respective static geometries, within the context of nonlinear electrodynamics. For the (3+1)-dimensional spacetime, it is found that the Einstein field equation imposes a contracting wormhole solution and the obedience of the weak energy condition. Nevertheless, in the presence of an electric field, the latter presents a singularity at the throat, however, for a pure magnetic field the solution is regular. For the (2+1)-dimensional case, it is also found that the physical fields are singular at the throat. Thus, taking into account the principle of finiteness, which states that a satisfactory theory should avoid physical quantities becoming infinite, one may rule out evolving (3+1)-dimensional wormhole solutions, in the presence of an electric field, and the (2+1)-dimensional case coupled to nonlinear electrodynamics.Comment: 17 pages, 1 figure; to appear in Classical and Quantum Gravity. V2: minor corrections, including a referenc

Neutral C60 effusive source for atomic collisions with fullerene

Review of scientific instruments, Vol.72, Nº9A neutral C60 effusive source was assembled in a crossed molecular-beam apparatus in order to perform atom–molecule electron transfer collisions and its calibration by time-of-flight mass spectrometry. This source consists of a stainless-steel oven where the C60 sublimation takes place. Typical operation temperatures are in the range of 723 up to 888 K. Through this setup the study of the ion pair formation process K C60→K C60 where K is a potassium atom can be performed in a wide range of collision energies 10 up to 500 eV . The results show evidence of negative ion formation being the ratio of intensities between the parent ion and fragment ions clearly dependent on the collision energy used

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

Deconvolving the information from an imperfect spherical gravitational wave antenna

We have studied the effects of imperfections in spherical gravitational wave antenna on our ability to properly interpret the data it will produce. The results of a numerical simulation are reported that quantitatively describe the systematic errors resulting from imperfections in various components of the antenna. In addition, the results of measurements on a room-temperature prototype are presented that verify it is possible to accurately deconvolve the data in practice.Comment: 5 pages, 2 figures, to be published in Europhysics Letter

Thermal diagnostic of the Optical Window on board LISA Pathfinder

Vacuum conditions inside the LTP Gravitational Reference Sensor must comply with rather demanding requirements. The Optical Window (OW) is an interface which seals the vacuum enclosure and, at the same time, lets the laser beam go through for interferometric Metrology with the test masses. The OW is a plane-parallel plate clamped in a Titanium flange, and is considerably sensitive to thermal and stress fluctuations. It is critical for the required precision measurements, hence its temperature will be carefully monitored in flight. This paper reports on the results of a series of OW characterisation laboratory runs, intended to study its response to selected thermal signals, as well as their fit to numerical models, and the meaning of the latter. We find that a single pole ARMA transfer function provides a consistent approximation to the OW response to thermal excitations, and derive a relationship with the physical processes taking place in the OW. We also show how system noise reduction can be accomplished by means of that transfer function.Comment: 20 pages, 14 figures; accepted for publication in Class. Quantum Gra

Perfil de expressão gênica global no músculo esquelético de ovinos por meio de microarrays.

O perfil de expressão gênica global no músculo esquelético de cordeiros de quatro grupos genéticos de ovinos foi comparado por meio de microarrays de oligonucleotídeos. As análises indicaram 262 transcritos diferencialmente expressos entre os grupos genéticos. Um total de 23 transcritos de funções conhecidas foram diferencialmente expressos, sendo dez deles apenas na comparação Morada Nova x Somalis Brasileira. Dentre os genes diferencialmente expressos, aqueles envolvidos com características de importância para a produção de carne, destacaram-se: MyoD e IGFBP4 (desenvolvimento muscular), PGDS e SCD (biosíntese de ácidos graxos), C/EBP &#948; e PPAR&#947; (adipogênese) e PYGL, GLUT-3, GGTA1 e ATP5G1 (metabolismo energético). Os resultados da técnica de microarray foram validados por meio de qPCR. Estes transcritos podem ser considerados marcadores expressos úteis para a seleção de cordeiros nas condições estudadas. A seleção para polimorfismos nestes genes pode conferir maior marmoreio e deposição de massa muscular, que são características ligadas diretamente a quantidade, a qualidade e a aceitação da carne. Global gene expression profile in skeletal muscle of sheep by microarray. Abstract: The global gene expression profile in muscle of four genetic groups of hair sheep were compared by oligonucleotide microarray. The analyses showed that 262 transcripts were differentially expressed among the four genetic groups. A total of 23 genes of known function were differentially expressed, with 10 transcripts differentially expressed only in the comparison between Morada Nova x Brazilian Somali. Among the differentially expressed genes, those involved with important features for the production of meat, stood out: IGFBP4 and MyoD (muscle growth), and PGDS (SCD biosynthesis of fatty acids), C/EBP&#948; and PPAR&#947; (adipogenesis) and PYGL, GLUT-3, and GGTA1 ATP5G1 (energy metabolism). The results of the microarray were validated by qPCR. These transcripts can be considered useful markers expressed in the selection of lambs under the conditions studied here. Screening for polymorphisms in these genes may confer greater marbling deposition and muscle mass, which are features directly linked to quantity, quality and acceptability of meat

Cabras mestiças: opção para a produção de leite no Nordeste do Brasil.

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