2,662 research outputs found

    Symmetries in Classical Field Theory

    Full text link
    The multisymplectic description of Classical Field Theories is revisited, including its relation with the presymplectic formalism on the space of Cauchy data. Both descriptions allow us to give a complete scheme of classification of infinitesimal symmetries, and to obtain the corresponding conservation laws.Comment: 70S05; 70H33; 55R10; 58A2

    Model Comparison to Interpret the Kinetics of in vitroGas Production with Bovine Excreta Used as Inoculum.

    Get PDF
    New models to help interpret the kinetics of in vitrogas production with bovine excreta used as inoculum were suggested. Samples of L. leucocephala, G. sepiumand P. maximum, with different gas production profiles, were used. The samples were submitted to the procedure for gas production and the volumes were determined every 3 h, in the first 30 h; then at 36; 48; 72 and 96 h. Five models were compared (two monophase and three biphase), and the parameters for better adjustment were determined. Mean squared error and the Durbin-Watson test were used as comparison criteria. It was concluded that the monophase models fall short to describe the kinetics of in vitrogas production with bovine excreta; whereas the biphase models with simple exponential components are useful. The biphase equation, where V = 0 for t < L and V = B * (1 – EXP (- C * (t - L))) for t ≥L classified as the most useful work is done with syringes

    Acaricide resistance of Rhipicephalus (Boophilus) microplus in State of Mato Grosso do Sul, Brazil.

    Get PDF
    This study was conducted to obtain an epidemiological view of acaricide resistance in populations of Rhipicephalus (Boophilus) microplus in the State of Mato Grosso do Sul. Twenty-four tick samples were collected from municipalities in the State where farmers had reported concerns about resistance to or failure of tick control. These ticks were subjected to in vitro resistance detection assays using the adult immersion test (AIT). The efficacy of alpha-cypermethrin, cypermethrin and amitraz treatments on samples collected throughout the State was generally poor. AIT showed efficacy ≥ 90% from the use of DDVP + chlorfenvinphos) (20 out of 21 municipalities), dichlorvos + cypermethrin (10 out of 16 municipalities) and cypermethrin + citronella + chlorpyrifos + piperonyl butoxide (20 out of 21 municipalities). PCR assays were used to detect the presence of pyrethroid resistance-associated sodium channel gene mutation. Larvae from three different populations that had previously been diagnosed as pyrethroid-resistant, through AIT, were evaluated. The PCR assays showed that the pyrethroid resistance-associated gene mutation was absent from these three populations. This study confirms that the emergence of resistance is a constant challenge for the livestock industry, and that development of resistance continues to be a major driver for new antiparasitic drugs to be developed

    Unambiguous Formalism for Higher-Order Lagrangian Field Theories

    Get PDF
    The aim of this paper is to propose an unambiguous intrinsic formalism for higher-order field theories which avoids the arbitrariness in the generalization of the conventional description of field theories, which implies the existence of different Cartan forms and Legendre transformations. We propose a differential-geometric setting for the dynamics of a higher-order field theory, based on the Skinner and Rusk formalism for mechanics. This approach incorporates aspects of both, the Lagrangian and the Hamiltonian description, since the field equations are formulated using the Lagrangian on a higher-order jet bundle and the canonical multisymplectic form on its dual. As both of these objects are uniquely defined, the Skinner-Rusk approach has the advantage that it does not suffer from the arbitrariness in conventional descriptions. The result is that we obtain a unique and global intrinsic version of the Euler-Lagrange equations for higher-order field theories. Several examples illustrate our construction.Comment: 21 pages; 4 diagrams; (this version) corrected typos; moved paragraphs; publishe

    La artroplastia de Neer en las fracturas complejas del húmero proximal

    Get PDF
    Se estudian los resultados obtenidos después del tratamiento agudo de una serie de 32 pacientes diagnosticados de fractura en cuatro fragmentos del húmero proximal a los que se les implantó una hemiartroplastia tipo Neer I. Se llevó a cabo una evaluación clínica-radiológica de los pacientes y para la evaluación de los resultados se aplicaron los criterios de Neer. Los resultados globales obtenidos son de un 69% entre buenos y regulares y de un 31% con resultado malo. El anclaje de las tuberosidades concreta el mayor índice de complicaciones, que junto a otras totalizan un 18% de los casos. El éxito en dicho anclaje se ha correlacionado significativamente con el resultado funcional (p=0,0019). La técnica meticulosa junto con el adecuado protocolo rehabilitador se señalan como puntos esenciales para el éxito.We study the results obtained after acute treatment of a group of 32 patients diagnosed of four-fragment fracture of the proximal humerus in whom a Neer I hemiarthroplasty was used. The patients were assessed with clinic and radiological parameters, and for the evaluation of the results Neer criteria were used. The global results obtained were 69% of good and fair and 31% of bad results. The tuberosities attachment concentrate the great complication index, that together with other complications acconist for 18% of the cases. The success of the attachment had a positive correlation with functional results (p=0.0019). A meticulous technique joined with a good rehabilitation program is pointed as essential for being successful

    Classical field theory on Lie algebroids: Variational aspects

    Full text link
    The variational formalism for classical field theories is extended to the setting of Lie algebroids. Given a Lagrangian function we study the problem of finding critical points of the action functional when we restrict the fields to be morphisms of Lie algebroids. In addition to the standard case, our formalism includes as particular examples the case of systems with symmetry (covariant Euler-Poincare and Lagrange Poincare cases), Sigma models or Chern-Simons theories.Comment: Talk deliverd at the 9th International Conference on Differential Geometry and its Applications, Prague, September 2004. References adde

    Comparison between FS-MPC control strategy for an UPS inverter application in α-β and abc frames

    Get PDF
    The voltage source inverter (VSI) of an uninterruptible power supply (UPS) is a system where the main objective is to obtain a high quality output sinusoidal voltage with independence on the output load. For this reason, it includes an output LC filter. The presence of the filter increases the complexity of the controller design thus it is necessary to evaluate the performance of the control strategy in terms of the output voltage quality and computational cost of the algorithm. In this paper, both analysis are developed for the finite states model predictive control (FS-MPC) of a VSI performed in the abc and α-βframes. Both algorithms are summarized and compared in order to establish an objective criteria to choose among them when a hardware implementation is developed. Simulation results are presented for both algorithms to validate the analysis

    High-throughput amplicon sequencing-based analysis of active fungal communities inhabiting grapevine after hot-water treatments reveals unexpectedly high fungal diversity

    Full text link
    [EN] The ecology of total fungal communities in grapevine is so far largely derived from studies on culture-dependent methods or cultivation-independent rDNA approaches. Sequencing the ribosomal RNA transcripts (rRNA) would rather reveal the functionally and metabolically active important taxa of the fungal community and provide insights into its activity in the wood. The present study investigated changes in the potentially active fungal communities of internal grapevine wood after Hot-Water Treatment (HWT) in planting material from Czech Republic and Spain at two different times during the propagation process and from two plant zones. We examined fungal communities using both traditional isolation into culture and high-throughput amplicon sequencing (HTAS) of the internal transcribed spacer 2 (ITS2) region in extracted total RNA. HTAS from metatranscriptomic RNA increased the resolution of the fungal community analysis and revealed a highly diverse mycobiota of grapevine wood compared to the traditional method. Fungal diversity differed between grapevine genotypes and showed a temporal variation over the vegetative period. Grapevine planting materials exhibited high fungal diversity after HWT, which demonstrates that the HWT process does not sterilize the internal wood of grapevine. HWT reduced the infection caused by fungal trunk disease pathogens but was not completely effective in eliminating their growth. This study provides important and practically useful insights into the dynamics of active fungal communities in hot-water treated plants, and represents the first study of active fungal communities on grapevine grafted plants by comparing traditional and next-generation sequencing methods. (C) 2018 Elsevier Ltd and British Mycological Society. All rights reserved.This work was supported by Projects No. LD14051 from the Ministry of Education, Youth and Sports, Czech Republic covered by COST Action FA1303, and No. CZ.02.1.01/0.0/0.0/16_025/0007314 "Multidisciplinary research to increase application potential of nanomaterials in agricultural practice" from EFRR (Grant provider: Ministerstvo Skolstvi, mladeze a telovychovy Ceske republiky (MSMT). Access to computing and storage facilities owned by parties and projects contributing to the National Grid Infrastructure MetaCentrum provided under the programme "Projects of Large Research, Development, and Innovations Infrastructures" (CESNET LM2015042), is greatly appreciated. David Gramaje was supported by the DOC-INIA program from the National Institute for Agronomic Research (INIA), co-funded by the European Social Fund. The authors are grateful for the technical assistance of Jesus Alfonso Crespo and Aitor Gavara Vidal.Eichmeier, A.; Pecenka, J.; Penazova, E.; Baranek, M.; Català, S.; León Santana, M.; Armengol Fortí, J.... (2018). High-throughput amplicon sequencing-based analysis of active fungal communities inhabiting grapevine after hot-water treatments reveals unexpectedly high fungal diversity. Fungal Ecology. 36:26-38. https://doi.org/10.1016/j.funeco.2018.07.011S26383
    corecore