568 research outputs found

    Current-Carrying Cosmic Strings in Scalar-Tensor Gravities

    Get PDF
    We study the modifications on the metric of an isolated self-gravitating bosonic superconducting cosmic string in a scalar-tensor gravity in the weak-field approximation. These modifications are induced by an arbitrary coupling of a massless scalar field to the usual tensorial field in the gravitational Lagrangian. The metric is derived by means of a matching at the string radius with a most general static and cylindrically symmetric solution of the Einstein-Maxwell-scalar field equations. We show that this metric depends on five parameters which are related to the string's internal structure and to the solution of the scalar field. We compare our results with those obtained in the framework of General Relativity.Comment: 23 pages, no figures, LATEX fil

    Anti-inflammatory activity of Lychnophora passerina, Asteraceae (Brazilian “Arnica”)

    Get PDF
    AbstractEthnopharmacological relevanceLychnophora passerina (Asteraceae), popularly known as “arnica,” is used to treat inflammation, pain, rheumatism, contusions, bruises and insect bites in Brazilian traditional medicine.Materials and methodsThe anti-inflammatory activity of crude ethanolic extract of aerial parts of L. passerina and its ethyl acetate and methanolic fractions had their abilities to modulate the production of NO, TNF-α and IL-10 inflammatory mediators in LPS/IFN-γ-stimulated J774.A1 macrophages evaluated. Moreover, the crude ethanolic extract and derived fractions were also in vivo assayed by carrageenan-induced paw oedema in mice.ResultsIn vitro assays showed remarkable anti-inflammatory activity of L. passerina crude ethanolic extract (EE) and its ethyl acetate (A) and methanolic (M) fractions, through the inhibition of production of NO and TNF-α inflammatory mediators and induction of production of IL-10 anti-inflammatory cytokine. In vivo assays showed anti-inflammatory activity for EE 10% ointment, similar to the standard drug diclofenac gel. The A and M fraction ointments 20% presented anti-inflammatory activity.ConclusionThe results obtained showed that possible anti-inflammatory effects of EE and its A and M fractions may be attributed to inhibition pro-inflammatory cytokines production, TNF-α and NO and to increased IL-10 production. EE, A and M ointments showed topical in vivo anti-inflammatory activity. The in vivo anti-inflammatory activity of EE of L. passerina may be related to synergistic effects of different substances in the crude extract. Therefore, traditional use of aerial parts of L. passerina in the inflammatory conditions could be beneficial to treat topical inflammatory conditions, as evidenced by the present study

    Desempenho da colhedora de milho Penha CLM-350: parte II - sistemas de debulhamento e limpeza

    Get PDF
    With the aim of quantifying the shelling" and cleaning systems performance for the Penha CLM-350 harvester, the percentage of loss of corn kernels, which octirred in the straw outlet was determined, as well as, the percentage of debris, in the packaged corn. Taking the corn kernels harvested by the snapping rolls as 100%, the percentage of loss from the shelling and cleaning systems were determined, as well as, the percentage of debris in the packaged corn for the various treatments. The average moisture content for the corn was 15,78% (w.b.). The corresponding treatments for the shelling and cleaning" systems are the tangencial velocity of the shelling cylinder, or the angular velocity of the aspirator considering the geometric configuration of the machine. The analysis of variance with the F tests at 1% e 5% probability level were used to analyse the data, and Tukey's test was used for comparison between means. The statistical analysis showed that the angular velocity of the aspirator, related to the percentage of loss in the straw outlet, was highly significant, making possible the assumption of a linear relationship between the two parameters for the testing conditions. The comparison between means showed that the percentage of debris in the packaged corn were significant for the treatments D (1241,7 rpm) and E(820 rpm), the last one with the higher mean. A more accurate analysis of the data sugests that the percentage of debris, would depend more on the material flow through the harvester, than the rotation of the feeding auger.Com a finalidade de quantificar o desempenho dos sistemas de debulhamento e limpeza da colhedora Penha CLM-350,, estudou-se as perdas percentuais era grão de milho, ocorridos na saída de palhas, bem como a porcentagem de impurezas, presente no milho ensacado. Tomando-se como 100% os grãos de milho colhidos pelo sistema espigador, determinou-se o valor percentual perdido pelos sistemas de debulhamento e limpeza, bem como a porcentagem de impurezas presente nos grãos de milho ensacado, nos diversos tratamentos estudados. O teor médio de umidade foi de 15,78% (b.u.). Os tratamentos correspondentes ao sistema de debulhamento e limpeza são as velocidades periféricas do debulhador ou as rotações do aspirador em faces da configuração geométrica da máquina. Os resultados obtidos foram estudados através da análise de variância, empregando-se os testes F, aos níveis de 1% e 5% de probabilidade e o teste Tukey, para a comparação estatística entre as médias. A análise estatística para verificar a influência da rotação do aspirador, era relação a porcentagem de grãos de milho perdidos na saída de palhas, mostrou diferenças altamente significativas, podendo-se admitir uma relação direta entre os dois parâmetros nas condições do ensaio. Com relação a rotação do aspirador e a porcentagem de impurezas, presentes nos grãos de milho ensacados, os testes das médias revelaram significância entre os tratamento D (1241,7 rpm) e E (820 rpm) sendo que este último apresentou a maior média. Uma análise mais acurada dos resultados sugere que a porcentagem de impurezas, estaria mais na dependência das relações de fluxo através da colhedora, do que propriamente do regime do aspirador

    Desempenho da colhedora de milho Penha CLM-350: parte I - sistema espigador

    Get PDF
    Com o propósito de avaliar a colhedora Penha CLM-350, visando fornecer subsídios aos projetos e usuários, realizou-se o presente trabalho, onde foi estudada a eficácia do sistema espigador, determinando-se a porcentagem de milho colhido para os diversos tratamentos estudados. Definiu-se um parâmetro adimensional U, que é a relação entre a velocidade periférica dos roletes e a velocidade de deslocamento da colhedora. Procurou-se relacionar as diversos tratamentos U, com os valores percentuais de grãos de milho colhidos e perdidos no solo. Os resultados foram estudados através da análise de variância, empregando-se o teste F, aos níveis de 1% e 5% de probabilidade e o teste Tukey para a comparação estatística entre as médias.This work was designed with the aim of evaluating the performance of the Penha CLM-350 corn combine, to furnish data to designers and users. The efficiency of the ear picking system was studied, and the percentage of the harvested corn was determined for the various treatments considered. A dimensionless U parameter was defined as the ratio between the peripheral speed of the snapping rolls and the speed of the harvester. The U terms were related to the percentages of corn harvested and corn lost on the ground. The analysis of variance with the F test at 1% and 5% probability levels was utilized to analyse the data, and Tukey's test was utilized for comparison between means. The statistical analysis showed that the treatment were not significant for the percentage of harvested corn, the efficiency maintained above 84,42% for the test conditions. For the conditions tested the values were limited by mechanical characteristics of the combine, particularly the transmission ratio. This suggests the design of a mechanism, which should provide the possibility of changing the transmission ratio from the tractor power take-off to the snapping rolls. This would provide a wider range of variation for U and could provide a mathematical relationship with efficiency

    Coulomb and nuclear breakup effects in the single neutron removal reaction 197Au(17C,16C gamma)X

    Get PDF
    We analyze the recently obtained new data on the partial cross sections and parallel momentum distributions for transitions to ground as well as excited states of the 16C core, in the one-neutron removal reaction 197Au(17C,16C gamma)X at the beam energy of 61 MeV/nucleon. The Coulomb and nuclear breakup components of the one-neutron removal cross sections have been calculated within a finite range distorted wave Born approximation theory and an eikonal model, respectively. The nuclear contributions dominate the partial cross sections for the core excited states. By adding the nuclear and Coulomb cross sections together, a reasonable agreement is obtained with the data for these states. The shapes of the experimental parallel momentum distributions of the core states are described well by the theory.Comment: Revtex format, two figures included, to appear in Phys. Rev. C. (Rapid communications

    Nested species-rich networks of scavenging vertebrates support high levels of interspecific competition

    Full text link
    Disentangling the processes that shape the organization of ecological assemblages and its implications for species coexistence is one of the foremost challenges of ecology. Although insightful advances have recently related community composition and structure with species coexistence in mutualistic and antagonistic networks, little is known regarding other species assemblages, such as those of scavengers exploiting carrion. Here we studied seven assemblages of scavengers feeding on ungulate carcasses in mainland Spain. We used dynamical models to investigate if community composition, species richness and structure (nestedness) affect species coexistence at carcasses. Scavenging networks showed a nested pattern in sites where highly efficient, obligate scavengers (i.e., vultures) were present and a non- nested pattern everywhere else. Griffon Vulture ( Gyps fulvus ) and certain meso- facultative mammalian scavengers (i.e., red fox, Vulpes vulpes, and stone marten, Martes foina ) were the main species contributing to nestedness. Assemblages with vultures were also the richest ones in species. Nested species- rich assemblages with vulture presence were associated with high carcass consumption rates, indicating higher interspecific competition at the local scale. However, the proportion of species stopping the consumption of carrion (as derived from the competitive dynamic model) stabilized at high richness and nestedness levels. This suggests that high species richness and nestedness may characterize scavenging networks that are robust to high levels of interspecific competition for carrion. Some facilitative interactions driven by vultures and major facultative scavengers could be behind these observations. Our findings are relevant for understanding species' coexistence in highly competitive systemsE. Sebastián- González and P. R. Guimarães benefited from FAPESP Research Foundation grants numbers 2011/17968- 2 and 2009/054422- 8, respectively; E. Sebastián- González is currently funded under the NSF grant NSF Award #1345247, M. Moleón by a postdoctoral grant from the Spanish Ministry of Education (Plan Nacional de I+D+I 2008- 2011), J. P. Gibert by an Other Fellowship and SBS Special Funds (U. of N.), and P. Mateo-Tomás by a postdoctoral grant of the Junta de Comunidades de Castilla-La Mancha and Fondo Social Europeo. The study was supported by the Spanish Ministry of Science and Innovation through projects 23/2007 ICTS- RBD, CGL2009- 12753- C02- 02, and CGL2012- 40013- C02- 02, FEDER funds, the Generalitat Valenciana through project ACOMP/2012/147, and the Junta de Andalucía through project RNM- 192

    Nested species- rich networks of scavenging vertebrates support high levels of interspecific competition.

    Get PDF
    Disentangling the processes that shape the organization of ecological assemblages and its implications for species coexistence is one of the foremost challenges of ecology. Although insightful advances have recently related community composition and structure with species coexistence in mutualistic and antagonistic networks, little is known regarding other species assemblages, such as those of scavengers exploiting carrion. Here we studied seven assemblages of scavengers feeding on ungulate carcasses in mainland Spain. We used dynamical models to investigate if community composition, species richness and structure (nestedness) affect species coexistence at carcasses. Scavenging networks showed a nested pattern in sites where highly efficient, obligate scavengers (i.e., vultures) were present and a non- nested pattern everywhere else. Griffon Vulture ( Gyps fulvus ) and certain meso- facultative mammalian scavengers (i.e., red fox, Vulpes vulpes, and stone marten, Martes foina ) were the main species contributing to nestedness. Assemblages with vultures were also the richest ones in species. Nested species- rich assemblages with vulture presence were associated with high carcass consumption rates, indicating higher interspecific competition at the local scale. However, the proportion of species stopping the consumption of carrion (as derived from the competitive dynamic model) stabilized at high richness and nestedness levels. This suggests that high species richness and nestedness may characterize scavenging networks that are robust to high levels of interspecific competition for carrion. Some facilitative interactions driven by vultures and major facultative scavengers could be behind these observations. Our findings are relevant for understanding species' coexistence in highly competitive systems

    Core excitation in Coulomb breakup reactions

    Full text link
    Within the pure Coulomb breakup mechanism, we investigate the one-neutron removal reaction of the type A(a,bγ\gamma)X with 11^{11}Be and 19^{19}C projectiles on a heavy target nucleus 208^{208}Pb at the beam energy of 60 MeV/nucleon. Our intention is to examine the prospective of using these reactions to study the structure of neutron rich nuclei. Integrated partial cross sections and momentum distributions for the ground as well as excited bound states of core nuclei are calculated within the finite range distorted wave Born approximation as well as within the adiabatic model of the Coulomb breakup. Our results are compared with those obtained in the studies of the reactions on a light target where the breakup proceeds via the pure nuclear mechanism. We find that the transitions to excited states of the core are quite weak in the Coulomb dominated process as compared to the pure nuclear breakup.Comment: Revtex format, five postscript figures included, to appear in Phys. Rev.
    corecore