365 research outputs found

    Asperciones de permetrina microencapsulada para el control de la garrapata sureña del ganado, Boophilus microplus (Aeari:Ixodidae), infestando novillas lecheras Holstein en Santa Cruz, Islas Vírgenes Americanas

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    The effectiveness of two acaricides was evaluated for control of populations of the southern cattle tick, Boophilus microplus on dairy cattle in St. Croix, U.S. Virgin Islands. Two different concentrations of a microencapsulated (ME) formulation of permethrin (0.05% and 0.10% ai) and one concentration of coumaphos emulsifiable concentrate (EC) (0.117% ai) were sprayed on Holstein heifers that had a natural infestation of ticks. The length of residual activity of EC coumaphos and ME permethrin at 0.05% (ai) was at least four days, and for ME permethrin at 0.10% ai at least seven days.There was no apparent increase in the residual activity period of ME permethrin in comparison to that in field trials of other formulations of permethrin against B. microplus. Percentage control for the three treatment groups from days 4 through 21 was ME permethrin (0.05% ai) 96%; ME permethrin (0.10% ai), 97%; coumaphos, 98.3%. There were no significant differences among the treatment groups (F = 2.21, df = 2,17, P> 0.10). This research confirms the usefulness of permethrin as an alternative to coumaphos for control of B. microplus populations on cattle.Se evaluaron dos acaricidas por su efectividad para controlar las poblaciones de la garrapata sureña Boophilus microplus en ganado lechero en Santa Cruz, Islas Virgenes Americanas. Se asperjaron dos concentraciones diferentes de una formulación microencapsulada (ME) de permetrína (0.05 y 0.10% ia) y una concentración de coumaphos concentrado emulsificable (0,117% ia) sobre novillas Holstein que presentaban una infestación natural de garrapatas. La actividad residual del coumaphos y la permetrina ME (0.05% ia) fue por lo menos de cuatro días y la de permetrina ME (0.10% ia) fue de por lo menos siete días. El largo del periodo residual de la permetrina ME sobre el Boophilus microplus no aumentó en comparación con experimentos de campo con otras formulaciones de permetrinas. El porcentaje de control para los tres tratamientos desde los días 4 al 21 fue: permetrina ME (0.05% ia), 96%; permetrina ME (0,10% ia), 97%; coumaphos, 98.3%. Las diferencias entre las medias de los diferentes tratamientos no fueron significativas (F= 2.21; g.l. = 2,17, P> 0.10). Esta investigación confirma que la permetrina es una alternativa para el control de B. microplus en poblaciones de ganado

    Chandra Observation of an X-ray Flare at Saturn: Evidence for Direct Solar Control on Saturn's Disk X-ray Emissions

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    Saturn was observed by Chandra ACIS-S on 20 and 26-27 January 2004 for one full Saturn rotation (10.7 hr) at each epoch. We report here the first observation of an X-ray flare from Saturn's non-auroral (low-latitude) disk, which is seen in direct response to an M6-class flare emanating from a sunspot that was clearly visible from both Saturn and Earth. Saturn's disk X-ray emissions are found to be variable on time scales of hours to weeks to months, and correlated with solar F10.7 cm flux. Unlike Jupiter, X-rays from Saturn's polar (auroral) region have characteristics similar to those from its disk. This report, combined with earlier studies, establishes that disk X-ray emissions of the giant planets Saturn and Jupiter are directly regulated by processes happening on the Sun. We suggest that these emissions could be monitored to study X-ray flaring from solar active regions when they are on the far side and not visible to Near-Earth space weather satellites.Comment: Total 12 pages including 4 figure

    Patient-reported outcomes measures and patient preferences for minimally invasive glaucoma surgical devices.

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    BackgroundMany therapeutic options are available to glaucoma patients. One recent therapeutic option is minimally invasive glaucoma surgical (MIGS) devices. It is unclear how patients view different treatments and which patient-reported outcomes would be most relevant in patients with mild to moderate glaucoma. We developed a questionnaire for patients eligible for MIGS devices and a patient preference study to examine the value patients place on certain outcomes associated with glaucoma and its therapies.ObjectivesTo summarize the progress to date.MethodsQuestionnaire development: We drafted the questionnaire items based on input from one physician and four patient focus groups, and a review of the literature. We tested item clarity with six cognitive interviews. These items were further refined. Patient preference study: We identified important benefit and risk outcomes qualitatively using semi-structured, one-on-one interviews with patients who were eligible for MIGS devices. We then prioritized these outcomes quantitatively using best-worst scaling methods.ResultsQuestionnaire testing: Three concepts were deemed relevant for the questionnaire: functional limitations, symptoms, and psychosocial factors. We will evaluate the reliability and validity of the 52-item draft questionnaire in an upcoming field test. Patient preference study: We identified 13 outcomes that participants perceived as important. Outcomes with the largest relative importance weights were "adequate IOP control" and "drive a car during the day."ConclusionsPatients have the potential to steer clinical research towards outcomes that are important to them. Incorporating patients' perspectives into the MIGS device development and evaluation process may expedite innovation and availability of these devices

    Discovery of Oxygen Kalpha X-ray Emission from the Rings of Saturn

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    Using the Advanced CCD Imaging Spectrometer (ACIS), the Chandra X-ray Observatory (CXO) observed the Saturnian system for one rotation of the planet (~37 ks) on 20 January, 2004, and again on 26-27 January, 2004. In this letter we report the detection of X-ray emission from the rings of Saturn. The X-ray spectrum from the rings is dominated by emission in a narrow (~130 eV wide) energy band centered on the atomic oxygen K-alpha fluorescence line at 0.53 keV. The X-ray power emitted from the rings in the 0.49-0.62 keV band is 84 MW, which is about one-third of that emitted from Saturn disk in the photon energy range 0.24-2.0 keV. Our analysis also finds a clear detection of X-ray emission from the rings in the 0.49-0.62 keV band in an earlier (14-15 April, 2003) Chandra ACIS observation of Saturn. Fluorescent scattering of solar X-rays from oxygen atoms in the H2O icy ring material is the likely source mechanism for ring X-rays, consistent with the scenario of solar photo-production of a tenuous ring oxygen atmosphere and ionosphere recently discovered by Cassini.Comment: 14 pages, 5 figures Astrophys. J Lett., in pres

    Solar Control on Jupiter's Equatorial X-ray Emissions: 26-29 November 2003 XMM-Newton Observation

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    During November 26-29, 2003 XMM-Newton observed soft (0.2-2 keV) X-ray emission from Jupiter for 69 hours. The low-latitude X-ray disk emission of Jupiter is observed to be almost uniform in intensity with brightness that is consistent with a solar-photon driven process. The simultaneous lightcurves of Jovian equatorial X-rays and solar X-rays (measured by the TIMED/SEE and GOES satellites) show similar day-to-day variability. A large solar X-ray flare occurring on the Jupiter-facing side of the Sun is found to have a corresponding feature in the Jovian X-rays. These results support the hypothesis that X-ray emission from Jovian low-latitudes are solar X-rays scattered from the planet's upper atmosphere, and suggest that the Sun directly controls the non-auroral X-rays from Jupiter's disk. Our study also suggests that Jovian equatorial X-rays can be used to monitor the solar X-ray flare activity on the hemisphere of the Sun that is invisible to space weather satellites.Comment: 12 pages, 4 figure

    Effects of pressure on diffusion and vacancy formation in MgO from non-empirical free-energy integrations

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    The free energies of vacancy pair formation and migration in MgO were computed via molecular dynamics using free-energy integrations and a non-empirical ionic model with no adjustable parameters. The intrinsic diffusion constant for MgO was obtained at pressures from 0 to 140 GPa and temperatures from 1000 to 5000 K. Excellent agreement was found with the zero pressure diffusion data within experimental error. The homologous temperature model which relates diffusion to the melting curve describes well our high pressure results within our theoretical framework.Comment: 4 pages, latex, 1 figure, revtex, submitted to PR

    Validation of Kepler's Multiple Planet Candidates. III: Light Curve Analysis & Announcement of Hundreds of New Multi-planet Systems

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    The Kepler mission has discovered over 2500 exoplanet candidates in the first two years of spacecraft data, with approximately 40% of them in candidate multi-planet systems. The high rate of multiplicity combined with the low rate of identified false-positives indicates that the multiplanet systems contain very few false-positive signals due to other systems not gravitationally bound to the target star (Lissauer, J. J., et al., 2012, ApJ 750, 131). False positives in the multi- planet systems are identified and removed, leaving behind a residual population of candidate multi-planet transiting systems expected to have a false-positive rate less than 1%. We present a sample of 340 planetary systems that contain 851 planets that are validated to substantially better than the 99% confidence level; the vast majority of these have not been previously verified as planets. We expect ~2 unidentified false-positives making our sample of planet very reliable. We present fundamental planetary properties of our sample based on a comprehensive analysis of Kepler light curves and ground-based spectroscopy and high-resolution imaging. Since we do not require spectroscopy or high-resolution imaging for validation, some of our derived parameters for a planetary system may be systematically incorrect due to dilution from light due to additional stars in the photometric aperture. None the less, our result nearly doubles the number of verified exoplanets.Comment: 138 pages, 8 Figures, 5 Tables. Accepted for publications in the Astrophysical Journa

    Planetary Candidates Observed by Kepler V: Planet Sample from Q1-Q12 (36 Months)

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    The Kepler mission discovered 2842 exoplanet candidates with 2 years of data. We provide updates to the Kepler planet candidate sample based upon 3 years (Q1-Q12) of data. Through a series of tests to exclude false-positives, primarily caused by eclipsing binary stars and instrumental systematics, 855 additional planetary candidates have been discovered, bringing the total number known to 3697. We provide revised transit parameters and accompanying posterior distributions based on a Markov Chain Monte Carlo algorithm for the cumulative catalogue of Kepler Objects of Interest. There are now 130 candidates in the cumulative catalogue that receive less than twice the flux the Earth receives and more than 1100 have a radius less than 1.5 Rearth. There are now a dozen candidates meeting both criteria, roughly doubling the number of candidate Earth analogs. A majority of planetary candidates have a high probability of being bonafide planets, however, there are populations of likely false-positives. We discuss and suggest additional cuts that can be easily applied to the catalogue to produce a set of planetary candidates with good fidelity. The full catalogue is publicly available at the NASA Exoplanet Archive.Comment: Accepted for publication, ApJ
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