130 research outputs found
The Volatile Composition of the Split Ecliptic comet 73P/Schwassmann-Wachmann 3: A Comparison of Fragments C and B
The composition of fragments C and B of the Jupiter-family comet 73P/Schwassmann-Wachmann 3 (SW3) was investigated in early April of 2006 at IR wavelengths using high-dispersion echelle spectroscopy. Both fragments were depleted in ethane, and C was depleted in most forms of volatile carbon. In particular, fragment C shows a severe depletion of CH_(3)OH but a "normal" abundance of HCN (which has a similar volatility). Thermal processing is a possible explanation, but since fragment B is perhaps sublimating fresher material because of the frequent outbursts and fragmentation, the observed depletions might have cosmogonic implications. The chemistry of the volatile ices in SW3, like in the Oort Cloud comet C/1999 S4 (LINEAR), may be associated with sublimation of icy mantles from precometary grains followed by subsequent gas-phase chemistry and recondensation
Non-detection of L-band Line Emission from the Exoplanet HD189733b
We attempt to confirm bright non-local thermodynamic equilibrium (non-LTE) emission from the exoplanet HD 189733b at 3.25 μm, as recently reported by Swain et al. based on observations at low spectral resolving power (λ/δλ ≈ 30). Non-LTE emission lines from gas in an exoplanet atmosphere will not be significantly broadened by collisions, so the measured emission intensity per resolution element must be substantially brighter when observed at high spectral resolving power. We observed the planet before, during, and after a secondary eclipse event at a resolving power λ/δλ = 27, 000 using the NIRSPEC spectrometer on the Keck II telescope. Our spectra cover a spectral window near the peak found by Swain et al., and we compare emission cases that could account for the magnitude and wavelength dependence of the Swain et al. result with our final spectral residuals. To model the expected line emission, we use a general non-equilibrium formulation to synthesize emission features from all plausible molecules that emit in this spectral region. In every case, we detect no line emission to a high degree of confidence. After considering possible explanations for the Swain et al. results and the disparity with our own data, we conclude that an astrophysical source for the putative non-LTE emission is unlikely. We note that the wavelength dependence of the signal seen by Swain et al. closely matches the 2ν_2 band of water vapor at 300 K, and we suggest that an imperfect correction for telluric water is the source of the feature claimed by Swain et al
Tasa de cesáreas según la aplicación de la Clasificación de Robson en Hospitales nivel III de Trujillo 2022
El estudio tuvo como objetivo determinar la tasa de cesáreas según la aplicación
de la Clasificación de Robson en hospitales nivel III de Trujillo 2022, la
metodología empleó un enfoque cuantitativo, tipo descriptivo, diseño no
experimental, de corte transversal. La muestra fue de 3249 mujeres atendidas por
parto de enero a septiembre del 2022. Se utilizó una ficha de datos basada en la
Clasificación de Robson. Se recolectó la información del Sistema Informático
Perinatal. La tasa de cesárea para el Hospital Belén de Trujillo fue de 74,30%
(1402/1887) y los grupos con mayor contribución fueron 5, 1, 10 y 3, mientras que,
en el Hospital Regional Docente de Trujillo fue de 75, 26% (1025/1362) y los
grupos con mayor contribución fueron 5, 10, 1 y 3. En ambos hospitales, las
características socioculturales predominantes fueron: jóvenes, con secundaria y
convivientes, y en características obstétricas fueron: multíparas, a término,
categoría simple, sin antecedente de cesárea, feto en cefálica e inicio de parto
espontáneo. La Clasificación de Robson extenderá la tasa de cesáreas y los
grupos con mayor contribución al incremento sobre el parámetro de la OMS (15%).The objective of the study was to determine the rate of cesarean sections
according to the application of the Robson Classification in level III hospitals of
Trujillo 2022, the methodology used a quantitative approach, descriptive type, non experimental design, cross-sectional. The sample consisted of 3,249 women
attended for childbirth from January to September 2022. A data sheet based on
the Robson Classification was used. Information was collected from the Perinatal
Information System. The caesarean section rate for the Hospital Belén de Trujillo
was 74.30% (1402/1887) and the groups with the highest contribution were 5, 1,
10 and 3, while at the Hospital Regional Docente de Trujillo it was 75, 26%
(1025/1362) and the groups with the greatest contribution were 5, 10, 1 and 3. In
both hospitals, the predominant sociocultural characteristics were: young people,
with secondary education and cohabiting, and in obstetric characteristics they
were: multiparous, at term, simple category, with no history of cesarean section,
cephalic fetus and spontaneous onset of labor. The Robson Classification will
extend the rate of cesarean sections and the groups with the greatest contribution
to the increase over the WHO parameter (15%).Tesi
A Laser Heterodyne Radiometer for Sampling Plumes of Icy Moons
We propose to develop an instrument capable of passively sampling plumes in icy moon environments for the components needed for life and habitability. The compact, low-mass and power, orbital instrument would be an occultation-viewing laser heterodyne radiometer (LHR) that collects sunlight passing through the plumes of icy moons to measure abundancies of key trace gases such as water vapor, methane, ethane, carbon dioxide, and their isotopes. Laser heterodyne radiometers are based on radio receiver technology and have been applied to measurements of trace gases in Earth and planetary atmospheres since the 1960s. Our team has recently adapted this technology into a 4U (20cm x 20cm x 10cm) CubeSat instrument to measure carbon dioxide, methane and water vapor in the Earth's atmosphere (launching on Virgin Orbit in 2019) and have the experience to develop this into a compact science payload to monitor gases emerging from icy moons of Saturn and Jupiter
Planetary Spectrum Generator: an accurate online radiative transfer suite for atmospheres, comets, small bodies and exoplanets
We have developed an online radiative-transfer suite
(https://psg.gsfc.nasa.gov) applicable to a broad range of planetary objects
(e.g., planets, moons, comets, asteroids, TNOs, KBOs, exoplanets). The
Planetary Spectrum Generator (PSG) can synthesize planetary spectra
(atmospheres and surfaces) for a broad range of wavelengths
(UV/Vis/near-IR/IR/far-IR/THz/sub-mm/Radio) from any observatory (e.g., JWST,
ALMA, Keck, SOFIA), any orbiter (e.g., ExoMars, Juno), or any lander (e.g.,
MSL). This is achieved by combining several state-of-the-art radiative transfer
models, spectroscopic databases and planetary databases (i.e., climatological
and orbital). PSG has a 3D (three-dimensional) orbital calculator for most
bodies in the solar system, and all confirmed exoplanets, while the
radiative-transfer models can ingest billions of spectral signatures for
hundreds of species from several spectroscopic repositories. It integrates the
latest radiative-transfer and scattering methods in order to compute high
resolution spectra via line-by-line calculations, and utilizes the efficient
correlated-k method at moderate resolutions, while for computing cometary
spectra, PSG handles non-LTE and LTE excitation processes. PSG includes a
realistic noise calculator that integrates several telescope / instrument
configurations (e.g., interferometry, coronagraphs) and detector technologies
(e.g., CCD, heterodyne detectors, bolometers). Such an integration of advanced
spectroscopic methods into an online tool can greatly serve the planetary
community, ultimately enabling the retrieval of planetary parameters from
remote sensing data, efficient mission planning strategies, interpretation of
current and future planetary data, calibration of spectroscopic data, and
development of new instrument/spacecraft concepts.Comment: Journal of Quantitative Spectroscopy and Radiative Transfer,
submitte
IRCS/Subaru Observations of Water in the Inner Coma of Comet 73P-B/Schwassmann-Wachmann 3: Spatially Resolved Rotational Temperatures and Ortho-Para Ratios
Comet 73P-B/Schwassmann-Wachmann 3 was observed with IRCS/Subaru at
geocentric distance of 0.074 AU on UT 10 May 2006. Multiple H2O emission lines
were detected in non-resonant fluorescence near 2.9 microns. No significant
variation in total H2O production rate was found during the (3 hour) duration
of our observations. H2O rotational temperatures and ortho-to-para abundance
ratios were measured for several positions in the coma. The temperatures
extracted from two different time intervals show very similar spatial
distributions. For both, the rotational temperature decreased from ~110 K to
~90 K as the projected distance from the nucleus increased from ~5 to ~30 km.
We see no evidence for OPR change in the coma. The H2O ortho-para ratio is
consistent with the statistical equilibrium value (3.0) for all spatially
resolved measurements. This implies a nuclear spin temperature higher than ~ 45
K.Comment: accepted for Icaru
Highly Depleted Ethane and Slightly Depleted Methanol in Comet 21P/Giacobini-Zinner: Application of Empirical g-Factors for CH3OH Near 50K
We report high resolution (lambda/delta lambda approximately 24,000) observations of Comet 21 P/Giacobini-Zinner (21P) between approximately 2.85 -- 3.54 micrometers, obtained with NIRSPEC at Keck 2 on UT 2005 June 03 (R(sub h) = 1.12 AU, delta = 1.45 AU). These simultaneously sampled multiple emissions from the v7 band of C2H6 and the v2 and v3 bands of CH3OH, together with several hot bands of H2O, permitting a direct measure of parent volatile abundances in 21P. Our spectra reveal highly depleted C2H6 (0.13-0.14 percent relative to H2O) and CH3OH/C2H6 approximately 10, consistent with previously published abundances from observations in the IR [1,2] and millimeter sub-mm (reporting CH3OH/H2O [3]) during its previous apparition in 1998. We observed similarly high CH3OH/C2H6, and also similar rotational temperature to that measured for 21 P, in Comet 8P/Tuttle [4,5]. We used our (higher signal-to-noise) NIRSPEC observations of 8P to produce effective (empirical) CH3OH g-factors for several lines in the v2 band. These will be presented together with interpretation of our results, including constraints on the spin temperature of water. We acknowledge support from the NASA Planetary Atmospheres, Planetary Astronomy, and Astrobiology Programs and from the NSF Astronomy and Astrophysics Research Grants Program
Mejora de la gestión energética, para la reducción del consumo de energía eléctrica de la empresa Pacifico Seguros
El autor no autoriza la publicación de la tesis
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