Symmetries of distributional domain wall geometries

Generalizing the Lie derivative of smooth tensor fields to distribution-valued tensors, we examine the Killing symmetries and the collineations of the curvature tensors of some distributional domain wall geometries. The chosen geometries are rigorously the distributional thin wall limit of self gravitating scalar field configurations representing thick domain walls and the permanence and/or the rising of symmetries in the limit process is studied. We show that, for all the thin wall spacetimes considered, the symmetries of the distributional curvature tensors turns out to be the Killing symmetries of the pullback of the metric tensor to the surface where the singular part of these tensors is supported. Remarkably enough, for the non-reflection symmetric domain wall studied, these Killing symmetries are not necessarily symmetries of the ambient spacetime on both sides of the wall

Comparación de métodos de muestreo para estimar la población del gorgojo del pimiento

Five sampling methods were evaluated simultaneously for their efficiency in estimating pepper weevil (Anthonomus eugenii Cano) populations. The use of yellow sticky traps was assessed superior to other methods when correlated with direct weevil counts. Comparison between sticky traps of eight different colors indicated that yellow and white traps are significantly more attractive to pepper weevils than light green, red, dark green, gray, blue or black. Commercially available Pherocon AM traps were tested for efficiency. Weevil catch in these traps was positively correlated with population density, but relationship was weak and weekly catch erratic. Factors affecting trap efficiency are mentioned.Una evaluación de cinco métodos de muestreo indicó la superioridad de trampas pegajosas amarillas en la estimación de los niveles de densidad del picudo del pimiento, Anthonomus eugenii Cano. Una comparación entre trampas pegajosas en ocho colores resultó en la determinación de que los colores amarillo y blanco atraen significativamente más adultos que otros colores. Además, se evaluó la utilidad y eficacia de las trampas comerciales Pherocon AM. Se encontró que la captura en éstas podía correlacionarse con los niveles de densidad del picudo del pimiento observados en el campo. Sin embargo, esta correlación resultó débil y errática debido en la mayoría de los casos a deficiencias en su diseño, con respecto a este picudo y su hábitat

SPIDERS ASSOCIATED WITH PAPAYA, CARICA PAPAYA L., IN PUERTO RICO

SPIDERS ASSOCIATED WITH PAPAYA, CARICA PAPAYA L., IN PUERTO RIC

The Hamilton-Jacobi analysis for higher-order modified gravity

The Hamilton-Jacobi $[HJ]$ study for the Chern-Simons $[CS]$ modification of general relativity $[GR]$ is performed. The complete structure of the Hamiltonians and the generalized brackets are reported, from these results the $HJ$ fundamental differential is constructed and the symmetries of the theory are found. By using the Hamiltonians we remove an apparent Ostrogradsky's instability and the new structure of the hamiltonian is reported. In addition, the counting of physical degrees of freedom is developed and some remarks are discussed

HOMOPTERA-AUCHENORRHYNCHA FROM RICE FIELDS IN PUERTO RICO

HOMOPTERA-AUCHENORRHYNCHA FROM RICE FIELDS IN PUERTO RIC

DAMAGE TO RICE SEEDLINGS BY HORTENSIA SIMILIS AND DRAECULACEPHALA SOLUTA IN COLOMBIA

DAMAGE TO RICE SEEDLINGS BY HORTENSIA SIMILIS AND DRAECULACEPHALA SOLUTA IN COLOMBI