Estudios relacionados con la langosta Rhammatocerus shistocercoides en los Llanos Orientales

Durante los años 1993 a 1995 se registró en los Llanos Orientales de Colombia un alarmante incremento de las poblaciones de una langosta identificada como Rhammatocerus schistocercoides (Rhen, 1906) en abril de 1995 por el Dr. N. Jago, del Natural Resources Institute of Chathan. La plaga se dispersó en los departamentos del Meta, Vichada, Guaviare y Casanare y afectó las praderas dedicadas a la ganadería y algunos cultivos agrícolas. Los estudios se enfocaron a definir el ciclo de vida, hábitos, preferencia alimenticia, enemigos naturales y aspectos de manejo de la plaga basados en la utilización de hongos entomopatógenos. De acuerdo con los estudios, la langosta R, schistocercoides presenta en las condiciones de Altillanura Colombiana una generación por año. Sus principales enemigos naturales son las aves, especialmente águilas, gavilanes y carracos, las garzas y alcaravanes efectúan un extraordinario control natural. Entre los insectos benéficos, se registraron varias especies, de las cuales se destaca la avispa predatora Prionyx sp., un cucarron de la familia Carabidae, predactor de huevos

Low-temperature rotational relaxation of CO in self-collisions and in-collisions with Ne and He

The low-temperature rotational relaxation of CO in self-collisions and in collisions with the rare-gas atoms Ne and He has been investigated in supersonic expansions with a combination of resonance-enhanced multiphoton ionization (REMPI) spectroscopy and time-of-flight techniques. For the REMPI detection of CO, a novel 2 + 1′ scheme has been employed through the A1 state of CO. From the measured data, average cross sections for rotational relaxation have been derived as a function of temperature in the range 5-100 K. For CO-Ne and CO-He, the relaxation cross sections grow, respectively, from values of ∼20 and 7 Å2 at 100 K to values of ∼65-70 and ∼20 A°2 in the 5-20 K temperature range. The cross section for the relaxation of CO-CO grows from a value close to 40 Å2 at 100 K to a maximum of 60 Å2 at 20 K and then decreases again to 40 Å2 at 5 K. These results are qualitatively similar to those obtained previously with the same technique for N2-N 2, N2-Ne, and N2-He collisions, although in the low-temperature range (T < 20 K) the CO relaxation cross sections are significantly larger than those for N2. Some discrepancies have been found between the present relaxation cross sections for CO-CO and CO-He and the values derived from electron-induced fluorescence experiments. © 2005 American Chemical Society.Financial support through the Ramón y Cajal program. Financial support from the EU Research Training Network “Reaction Dynamics”, Grant HPRNCT-1999-00007.Financial support from the Spanish Ministry of Education through the State Secretary of Education and University. Support from the Plan Andaluz de Investigación (Group FQM-205). Funding by the MEC of Spain under Grants FIS2004-00456 and BQU2002-04627-C02-02Peer Reviewe

Chromomagnetic Dipole Moment of the Top Quark Revisited

We study the complete one-loop contributions to the chromagnetic dipole moment $\Delta\kappa$ of the top quark in the Standard Model, two Higgs doublet models, topcolor assited technicolor models (TC2), 331 models and extended models with a single extra dimension. We find that the SM predicts $\Delta\kappa = - 0.056$ and that the predictions of the other models are also consitent with the constraints imposed on $\Delta\kappa$ by low-energy precision measurements.Comment: 20 pages, 5 figures, Updat

Biofunctionalized Polymer Nanomaterials: Implications on Shapes and Sizes

Nanotechnology has been one of the most widely used tools in various industries such as pharmaceutical, food, and chemistry, among others, for the encapsulation of compounds or even microorganisms. However, an analysis of the methodologies or polymer matrices to be used is rarely generated, and these in turn contribute to the objective of the product that is intended to be designed. In addition to the evaluation of its physicochemical, optical, and rheological characteristics, and others, are a set of technological tools that allow predicting the stability of a colloid, however, some of the factors that have less importance as the effect of the synthesis process on the shape and size that a structure may have, studies have been carried out to evaluate this phenomenon, which has become a determining factor in the design of any nanoscale material

Efficacy of celecoxib in treating symptoms of viral pharyngitis: A double-blind, randomized study of celecoxib versus diclofenac

This study compared the efficacy and safety of the cyclooxygenase-2 specific inhibitor celecoxib with the conventional non-steroidal anti-inflammatory drug diclofenac in the symptomatic treatment of viral pharyngitis. Adult patients from 27 study centers in Latin America were treated with oral doses of celecoxib 200 mg once daily or 200 mg twice daily, or diclofenac 75 mg twice daily for 5 days in a double-blind, randomized study. The primary efficacy assessment was 'Throat Pain on Swallowing' on day 3. In addition, secondary quality-of-life assessments were performed on days 3 and 5. All adverse events and treatment-emergent signs and symptoms were recorded. Data from 313 patients were evaluable for efficacy (105 celecoxib 200 mg once daily, 107 celecoxib 200 mg twice daily, 101 diclofenac 75 mg twice daily). The upper 95% confidence limits for the visual analog scale of 'Throat Pain on Swallowing' on day 3 for celecoxib 200 mg once daily relative to diclofenac 75 mg twice daily, and celecoxib 200 mg twice daily relative to diclofenac 75 mg twice daily were 9.26 and 7.83, respectively. All secondary efficacy and quality-of-life measures were clinically similar for the three treatment groups, and no statistically significant differences were detected. The incidences of treatment-emergent adverse events and withdrawals due to adverse events were similar for all groups, but numerically higher among patients taking diclofenac than celecoxib. More patients in the diclofenac group reported gastrointestinal complaints (7.3%) compared with those in the celecoxib groups (4.3% in the celecoxib 200 mg once-daily group and 3.4% in the celecoxib 200 mg twice-daily group). In conclusion, 5 days of treatment with celecoxib 200 mg once daily is as effective as diclofenac 75 mg twice daily in the symptomatic treatment of viral pharyngitis. Celecoxib 200 mg once daily is also as effective as celecoxib 200 mg twice daily in this condition

Selección de variables cuantitativas y clasificación de 22 acessiones de fríjol arbustivo (Phaseolus vulgaris L.).

La evaluación de 22 colectas y tres testigos de fríjol arbustivos procedentes de germoplasma de Corpoica en Mosquera, Colombia, permitió seleccionar variables que discriminan la variabilidad existente e identificar las colectas sobresalientes por parámetros morfológicos cuantitativos y componentes de rendimiento. Se seleccionaron las variables de mayor heredabilidad representadas por coeficiente de repetibilidad r 1 (Goodman y Paterniani, 1969), de las 24 variables cuantitativas en estudio, 14 cumplieron esta condición, las variables descartadas fueron las del estado de plántula, área foliar y rendimiento. El análisis por componentes principales de las 14 variables retenidas mostró como los tres primeros componentes explicaron el 88.49 por ciento de la variación total, donde los caracteres: días a floración, días a cosecha, peso de 100 semillas, número de semillas por vaina, ancho y longitud de la vaina, altura de cobertura, número de nudos, y longitud de epicotilo e hipocotilo fueron los que más aportaron a dicha variación. Las colectas del acervo Mesoamericano: Antioquia 21, Cauca 34 y Tolima 16, y del acervo Andino: Perú 5 (Poroto Largo) y Cundinamarca 148, presentaron el mejor comportamiento agronómico y alta variabilidad genética, por lo cual se considera de importancia en la conservación de su variabilidad y como posibles progenitoresFríjol-Phaseolus vulgari

The Imaging Magnetograph eXperiment (IMaX) for the Sunrise balloon-borne solar observatory

The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by four institutions in Spain that flew on board the Sunrise balloon-borne telesocope in June 2009 for almost six days over the Arctic Circle. As a polarimeter IMaX uses fast polarization modulation (based on the use of two liquid crystal retarders), real-time image accumulation, and dual beam polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the instrument uses a LiNbO3 etalon in double pass and a narrow band pre-filter to achieve a spectral resolution of 85 mAA. IMaX uses the high Zeeman sensitive line of Fe I at 5250.2 AA and observes all four Stokes parameters at various points inside the spectral line. This allows vector magnetograms, Dopplergrams, and intensity frames to be produced that, after reconstruction, reach spatial resolutions in the 0.15-0.18 arcsec range over a 50x50 arcsec FOV. Time cadences vary between ten and 33 seconds, although the shortest one only includes longitudinal polarimetry. The spectral line is sampled in various ways depending on the applied observing mode, from just two points inside the line to 11 of them. All observing modes include one extra wavelength point in the nearby continuum. Gauss equivalent sensitivities are four Gauss for longitudinal fields and 80 Gauss for transverse fields per wavelength sample. The LOS velocities are estimated with statistical errors of the order of 5-40 m/s. The design, calibration and integration phases of the instrument, together with the implemented data reduction scheme are described in some detail.Comment: 17 figure

FCNC Top Quark Decays in Extra Dimensions

The flavor changing neutral top quark decay t -> c X is computed, where X is a neutral standard model particle, in a extended model with a single extra dimension. The cases for the photon, X= \gamma$, and a Standard Model Higgs boson, X = H, are analyzed in detail in a non-linear$R_\xi gauge. We find that the branching ratios can be enhanced by the dynamics originated in the extra dimension. In the limit where 1/R >> ->, we have found Br(t -> c \gamma) \simeq 10^{-10} for 1/R = 0.5 TeV. For the decay t -> c H, we have found Br(t -> cH) \simeq 10^{-10} for a low Higgs mass value. The branching ratios go to zero when 1/R -> \infty.Comment: Accepted to be published in the Europ. Phys. Jour. C; 16 pages, 2 figure