787 research outputs found

    Graviton emission from a higher-dimensional black hole

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    We discuss the graviton absorption probability (greybody factor) and the cross-section of a higher-dimensional Schwarzschild black hole (BH). We are motivated by the suggestion that a great many BHs may be produced at the LHC and bearing this fact in mind, for simplicity, we shall investigate the intermediate energy regime for a static Schwarzschild BH. That is, for (2M)1/(n−1)ω∌1(2M)^{1/(n-1)}\omega\sim 1, where MM is the mass of the black hole and ω\omega is the energy of the emitted gravitons in (2+n)(2+n)-dimensions. To find easily tractable solutions we work in the limit l≫1l \gg 1, where ll is the angular momentum quantum number of the graviton.Comment: 10 pages, 8 figures, references added, typos corrected. Graviton degeneracy factor included; main results remain unchange

    Operation of a perfusive catalytic membrane with nonlinear kinetics

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    Operation of a perfusive catalytic curved membrane is systematized into different transport-reaction regimes. The internal viscous permeation improves the catalyst performance, measured here by the effectiveness factor and by its enhancement relative to purely diffusive conditions. A theoretical analysis is presented for nonlinear kinetic expressions, which are suitable to describe the consumption of a reactant in many (bio)catalytic systems. The kinetic and transport parameters required to attain maximum enhancement are related by simple design rules, which depend on the form of the reaction rate law (namely on the order of reaction and dimensionless inhibition constant). For zero-order reactions, these optimum conditions correspond to attaining negligible concentration at a position inside the membrane, while may be interpreted in general as separating situations of severe mass transfer resistance from cases of high effectiveness. It is important to incorporate the correct form of the kinetic expression in the analysis, so that the predictions can be used in a quantitative manner. The results for the different regimes are compiled in enhancement plots and in Peclet–Thiele diagrams. Moreover, the study also yielded new results for the nonlinear reaction–diffusion problem in a curved membrane with its two surfaces exposed to different concentrations, a case of relevance in membrane reactors

    GestĂŁo de infestantes de inverno e primavera em vinha e olival com um fertilizante ecolĂłgico com propriedades herbicidas

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    Weeds reduce crop yields and require annual measures of control, although they can provide important ecological benefits. In this work, the efficacy was tested of an ecological fertilizer with herbicidal properties (Bioscrop HerbitecÂź) which in high concentrations (10-15%) can have a similar effect to a contact herbicide. The composition of the product is 6.0 % of water-soluble potassium oxide, 54.7 % of organic acids and 39.3 % of dispersants and diluents. The product was tested in six field trials during two years, which included two vineyards and two olive orchards and winter and spring vegetation. In each experiment three treatments were imposed, being the product applied at the concentrations of 10% and 15% and a non-treated control. In treated plots, the entire ground surface (rows and inter-rows) was sprayed. The evaluation of the effect of the treatments on vegetation was assessed by the pin point and grid methods which consisted of determining the percentage of damaged and not damaged vegetation and bare soil. The production of dry biomass of weeds was also evaluated as a measure of the persistence of the damage on vegetation. The floristic composition of the stands was also recorded to evaluate the specific susceptibility of the weeds to the different treatments. The results showed that the product severely damaged the vegetation, and the effect persisted for more than a month. The application of the product caused a severe reduction in the aboveground biomass while keeping the soil protected, showing a useful compromise between the reduction in weed competition and the maintenance of ground cover. Some species were severely damaged while others seemed to have benefited in relative terms, suggesting that the effectiveness of the product will be dependent on the weed species present.As infestantes reduzem a produtividade das culturas e requerem medidas anuais de combate, embora tambĂ©m possam fornecer importantes serviços ecossistĂ©micos. Neste trabalho foi testada a eficĂĄcia de um produto ecolĂłgico (Bioscrop HerbitecÂź) que, em altas concentraçÔes (10- 15%), pode ter um efeito semelhante ao de um herbicida de contato. O produto contĂ©m 6,0 % de Ăłxido de potĂĄssio solĂșvel em ĂĄgua, 54,7 % de ĂĄcidos orgĂąnicos e 39,3 % de dispersantes e diluentes. O produto foi testado em seis ensaios de campo, em duas vinhas e dois olivais e sobre vegetação de inverno e de primavera. Em cada ensaio foram testados trĂȘs tratamentos, correspondentes Ă  aplicação do produto em duas concentraçÔes (10 e 15%) e uma modalidade testemunha. Nos talhĂ”es tratados o produto foi aplicado nas linhas e entrelinhas. O efeito dos tratamentos na vegetação foi avaliado pelos mĂ©todos do ponto quadrado e da grelha, que consistiram em determinar o grau de cobertura do solo com vegetação danificada, nĂŁo danificada e solo nu. A produção de matĂ©ria seca das infestantes foi tambĂ©m avaliada como medida da persistĂȘncia do dano na vegetação. A composição florĂ­stica dos cobertos foi tambĂ©m registada como forma de avaliar a suscetibilidade especĂ­fica das infestantes aos diferentes tratamentos. Os resultados mostraram que o produto danificou severamente a vegetação e o efeito persistiu por mais de um mĂȘs. A aplicação do produto causou uma redução significativa da biomassa aĂ©rea, mas manteve o solo protegido, mostrando um equilĂ­brio interessante entre a redução da competição das infestantes e a proteção do solo. Algumas espĂ©cies foram fortemente danificadas, enquanto outras parecem ter beneficiado em termos relativos, sugerindo que a eficĂĄcia do produto dependerĂĄ das espĂ©cies infestantes presentesThe authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013). The results of the first year of studies of this work were extracted from the master's thesis in Agroecology of the first author (AntĂłnio Barreira)info:eu-repo/semantics/publishedVersio

    QCD-supression by Black Hole Production at the LHC

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    Possible consequences of the production of small black holes at the LHC for different scenarios with large extra dimensions are investigated. The effects from black hole production on some standard jet observables are examined, concentrating on the reduction of the QCD cross section. It is found that black hole production of partons interacting on a short enough distance indeed seem to generate a drastic drop in the QCD cross section. However from an experimental point of view this will in most cases be camouflaged by energetic radiation from the black holes

    Operational Observatory of the catalan sea (OOCS)

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    The Operational Observatory of the Catalan Sea (OOCS) recently created by the Operational Oceanography Group at CEAB-CSIC is presented. The OOCS aims at performing observations of the marine environment in the Catalan Sea and beyond, assessing, modelling and forecasting the hydrodynamic and biogeochemical processes of the region. Some of the biogeochemical variables available in the models and forecast are phytoplankton, zooplankton and nutrients. Although OOCS is expected to be fully operational in 2011, some of its services are already available to the public through a dedicated webpage http://www.ceab.csic.es/~simob/.Peer Reviewe

    Gametic and somatic embryogenesis through in vitro anther culture of different Citrus genotypes

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    Abstract: In vitro tissue culture represents a useful technique for advancing Citrus breeding and propagation. Among in vitro regeneration systems, anther culture is commonly used to produce haploids and doubled haploids for a fast-track producing homozygous lines, in comparison with the traditional self-pollination approach, which involves several generations of selfing. In addition, anthers culture can produce somatic embryos that can also be used for clonal propagation. In this study, two thermal shocks were applied to the anthers of six Citrus genotypes (two clementine and four sweet oranges), just after they were put in culture. The response obtained was different depending on the genotype: both clementines, namely Hernandina and Corsica, produced homozygous and triploid regenerants (microspore-derived embryos), whereas all of the analyzed regenerants from sweet oranges, three cultivars of Tarocco and Moro, produced heterozygous and diploid regenerants similar to the parental genotypes (somatic embryos)

    High correlation between Chagas' disease serology and PCR-based detection of Trypanosoma cruzi kinetoplast DNA in bolivian children living in an endemic area

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    Submitted by sandra infurna ([email protected]) on 2016-06-29T15:31:55Z No. of bitstreams: 1 carlos20_morel_etal_IOC_1994.pdf: 578671 bytes, checksum: 49c1bfe1a3334487aede673ca532654a (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-06-29T15:43:03Z (GMT) No. of bitstreams: 1 carlos20_morel_etal_IOC_1994.pdf: 578671 bytes, checksum: 49c1bfe1a3334487aede673ca532654a (MD5)Made available in DSpace on 2016-06-29T15:43:03Z (GMT). No. of bitstreams: 1 carlos20_morel_etal_IOC_1994.pdf: 578671 bytes, checksum: 49c1bfe1a3334487aede673ca532654a (MD5) Previous issue date: 1994Submitted by Angelo Silva ([email protected]) on 2016-07-07T11:16:53Z No. of bitstreams: 3 carlos20_morel_etal_IOC_1994.pdf.txt: 19093 bytes, checksum: d5ec7ae508e9468c358833ecf7cf1076 (MD5) carlos20_morel_etal_IOC_1994.pdf: 578671 bytes, checksum: 49c1bfe1a3334487aede673ca532654a (MD5) license.txt: 2991 bytes, checksum: 5a560609d32a3863062d77ff32785d58 (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-07-07T12:13:56Z (GMT) No. of bitstreams: 3 license.txt: 2991 bytes, checksum: 5a560609d32a3863062d77ff32785d58 (MD5) carlos20_morel_etal_IOC_1994.pdf: 578671 bytes, checksum: 49c1bfe1a3334487aede673ca532654a (MD5) carlos20_morel_etal_IOC_1994.pdf.txt: 19093 bytes, checksum: d5ec7ae508e9468c358833ecf7cf1076 (MD5)Made available in DSpace on 2016-07-07T12:13:56Z (GMT). No. of bitstreams: 3 license.txt: 2991 bytes, checksum: 5a560609d32a3863062d77ff32785d58 (MD5) carlos20_morel_etal_IOC_1994.pdf: 578671 bytes, checksum: 49c1bfe1a3334487aede673ca532654a (MD5) carlos20_morel_etal_IOC_1994.pdf.txt: 19093 bytes, checksum: d5ec7ae508e9468c358833ecf7cf1076 (MD5) Previous issue date: 1994Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de BioquĂ­mica e Biologia Molecular. LaboratĂłrio de Biologia Molecular e Doenças EndĂȘmicas. Rio de Janeiro, RJ, Brasil.UMR CNRS/ ORSTOM, GĂ©nĂ©tique MolĂ©culaire des Parasites et des Vecteurs. CP 9214, La Paz, Bolivia.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de BioquĂ­mica e Biologia Molecular. LaboratĂłrio de Biologia Molecular e Doenças EndĂȘmicas. Rio de Janeiro, RJ, Brasil.Universidad Mayor de San Andres. Instituto Boliviano de Biologia de Altura. La Paz, Bolivia.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de BioquĂ­mica e Biologia Molecular. LaboratĂłrio de Biologia Molecular e Doenças EndĂȘmicas. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de BioquĂ­mica e Biologia Molecular. LaboratĂłrio de Biologia Molecular e Doenças EndĂȘmicas. Rio de Janeiro, RJ, Brasil.UMR CNRS/ ORSTOM, GĂ©nĂ©tique MolĂ©culaire des Parasites et des Vecteurs. CP 9214, La Paz, Bolivia.The detection of Tr)tpunosomu crirzi kinetoplast DNA by polymerase chain reaction (PCR) amplification is a potentially powerful tool for the parasitological diagnosis of Chagas’ disease. We have applied this technique in a field situation in Bolivia, where 45 children from a primary school were subjected to serological testing, buffy coat analysis and PCR diagnosis. 26 of the 28 serology-positive individuals were also positive by PCR. In addition, two serology-negative children gave a positive result by PCR, including one who was positive in the buffy coat test. These results suggest that PCR detection of T. cruzi DNA in blood can be a very useful complement to serology in Chagas’ disease diagnosis in Bolivia

    Power transformers winding fault diagnosis by the on-load exciting current extended Park's vector approach

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    This paper presents the application of the on-load exciting current Extended Park's Vector Approach to diagnose incipient turn-to-turn winding faults in operating power transformers. Experimental and simulation test results demonstrate the effectiveness of the proposed technique, which is based on the spectral analysis of the AC component of the on-load exciting current Park's Vector modulus

    Nonequilibrium wetting

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    When a nonequilibrium growing interface in the presence of a wall is considered a nonequilibrium wetting transition may take place. This transition can be studied trough Langevin equations or discrete growth models. In the first case, the Kardar-Parisi-Zhang equation, which defines a very robust universality class for nonequilibrium moving interfaces, with a soft-wall potential is considered. While in the second, microscopic models, in the corresponding universality class, with evaporation and deposition of particles in the presence of hard-wall are studied. Equilibrium wetting is related to a particular case of the problem, it corresponds to the Edwards-Wilkinson equation with a potential in the continuum approach or to the fulfillment of detailed balance in the microscopic models. In this review we present the analytical and numerical methods used to investigate the problem and the very rich behavior that is observed with them.Comment: Review, 36 pages, 16 figure
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