Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
442
result(s) for
"Barnes, Jason"
Sort by:
Star Wars : complete locations
The ultimate reference book for the planets, cities, and battles of the Star wars galaxy! The cross-section artworks offer incredible levels of detail that take you far beyond what is seen on-screen-- even beyond freeze-frame!
Book
Effects of Orbital Eccentricity on Extrasolar Planet Transit Detectability and Light Curves
It is shown herein that planets with eccentric orbits are more likely to transit than circularly orbiting planets with the same semimajor axis by a factor of
\\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $( 1-e^{2}) ^{-1}$ \\end{document}
. If the orbital parameters of discovered transiting planets are known, as from follow‐up radial velocity observations, then the transit‐detected planet population is easily debiased of this effect. The duration of a planet’s transit depends on its eccentricity and longitude of periastron; transits near periastron are shorter, and those near apoastron last longer, for a given impact parameter. If fitting for the stellar radius with the other transit parameters, this effect causes a systematic error in the resulting measurements. If the stellar radius is instead held fixed at a value measured independently, then it is possible to place a lower limit on the planet’s eccentricity using photometry alone. Orbital accelerations cause a difference in the planet’s ingress and egress durations that lead to an asymmetry in the transit light curve that could be used along with the transit velocity measurement to uniquely measure the planet’s eccentricity and longitude of periapsis. However, the effect is too small to be measured with current technology. The habitability of transiting terrestrial planets found byKeplerdepends on those planets’ orbital eccentricities. WhileKeplerwill be able to place lower limits on those planets’ orbital eccentricity, the actual value for any given planet will likely remain unknown.
Journal Article
Jupiter and Saturn as Spectral Analogs for Extrasolar Gas Giants and Brown Dwarfs
With the advent of direct-imaging spectroscopy, the number of spectra from brown dwarfs and extrasolar gas giants is growing rapidly. Many brown dwarfs and extrasolar gas giants exhibit spectroscopic and photometric variability, which is likely the result of weather patterns. However, for the foreseeable future, point-source observations will be the only viable method to extract brown dwarf and exoplanet spectra. Models have been able to reproduce the observed variability, but ground-truth observations are required to verify their results. To that end, we provide visual and near-infrared spectra of Jupiter and Saturn obtained from the Cassini VIMS instrument. We disk-integrate the VIMS spectral cubes to simulate the spectra of Jupiter and Saturn as if they were directly imaged exoplanets or brown dwarfs. We present six empirical disk-integrated spectra for both Jupiter and Saturn with phase coverage of 1.°7–133.°5 and 39.°6–110.°2, respectively. To understand the constituents of these disk-integrated spectra, we also provide end-member (single-feature) spectra for permutations of illumination and cloud density, as well as for Saturn’s rings. In tandem, these disk-integrated and end-member spectra provide the ground truth needed to analyze point-source spectra from extrasolar gas giants and brown dwarfs. Lastly, we discuss the impact that icy rings, such as Saturn’s, have on disk-integrated spectra and consider the feasibility of inferring the presence of rings from direct-imaging spectra.
Journal Article
Hydrochlorothiazide vs. Chlorthalidone for the Treatment of Hypertension
Evidence-Based Answer Chlorthalidone reduces systolic blood pressure (SBP) by 10 mm Hg more than hydrochlorothiazide at equal dosages (12.5 to 25 mg daily) in patients using monotherapy. Low-dose chlorthalidone (6.25 mg daily) and controlled-release hydrochlorothiazide (12.5 mg daily; not currently available in the United States) reduce 24-hour ambulatory SBP and diastolic blood pressure (DBP), whereas immediate-release hydrochlorothiazide (12.5 mg daily) may only reduce daytime SBP. A 2016 RCT (N = 54) evaluated the effect of low-dose chlorthalidone and hydrochlorothiazide on mean 24-hour ambulatory blood pressure.2 Patients were 18 to 65 years of age (mean = 45 years of age) with essential hypertension (SBP of 140 to 159 mm Hg, DBP of 90 to 99 mm Hg) and an average blood pressure of 148/93 mm Hg.
Journal Article
Sea Surface and Hydrological Activity Observed in Titan’s Punga Mare
We present new evidence for active coastal and oceanic features in Titan’s Punga Mare observed in a high-phase Cassini Visual Infrared and Mapping Spectrometer observation of sun glint from the T110 flyby. We observe sunglint in a coastal channel, Apanohuaya Flumen, resulting from differing pixel contributions of land adjacent to the liquid-filled channel. Along the eastern shoreline, we identify a 5 μ m bright margin. A possible explanation for this brightening includes a coastal margin of capillary wave fields. We find additional evidence of variegated sea surface roughness in Fundy Sinus and isolated Sun glitter near Hawaiki Insulae. RADAR observations of debouches (where rivers meet bays) within Punga Mare overlap several bright 5 μ m pixels that indicate rough liquid surfaces. We postulate that a change in liquid flow regimes, possibly occurring as surface streamflow or bubble outburst events, may be responsible for surface roughness near these debouches. These observations imply air–sea–land interactions and active hydrology represented by possible streamflow are present in Titan’s sea district during the northern summer.
Journal Article
Selection and Characteristics of the Dragonfly Landing Site near Selk Crater, Titan
The factors contributing to the initial selection of a dune site near the Selk impact structure on Titan as the first landing site for the Dragonfly mission are described. These include arrival geometry and aerodynamic/aerothermodynamic considerations, illumination, and Earth visibility, as well as the likely presence of exposed deposits of water-rich material, potentially including materials where molten ice has interacted with organics. Cassini observations of Selk are summarized and interpreted: near-infrared reflectance and microwave emission data indicate water-rich materials in and around the crater. Radar topography data shows the rim of Selk to have slopes on multi-km scales reaching only ∼2° degrees, an order of magnitude shallower than early photoclinometric estimates.
Journal Article
Detection and mapping of hydrocarbon deposits on Titan
We report the identification of compounds on Titan's surface by spatially resolved imaging spectroscopy methods through Titan's atmosphere, and set upper limits to other organic compounds. We present evidence for surface deposits of solid benzene (C6H6), solid and/or liquid ethane (C2H6), or methane (CH4), and clouds of hydrogen cyanide (HCN) aerosols using diagnostic spectral features in data from the Cassini Visual and Infrared Mapping Spectrometer (VIMS). Cyanoacetylene (2‐propynenitrile, IUPAC nomenclature, HC3N) is indicated in spectra of some bright regions, but the spectral resolution of VIMS is insufficient to make a unique identification although it is a closer match to the feature previously attributed to CO2. We identify benzene, an aromatic hydrocarbon, in larger abundances than expected by some models. Acetylene (C2H2), expected to be more abundant on Titan according to some models than benzene, is not detected. Solid acetonitrile (CH3CN) or other nitriles might be candidates for matching other spectral features in some Titan spectra. An as yet unidentified absorption at 5.01‐μm indicates that yet another compound exists on Titan's surface. We place upper limits for liquid methane and ethane in some locations on Titan and find local areas consistent with millimeter path lengths. Except for potential lakes in the southern and northern polar regions, most of Titan appears “dry.” Finally, we find there is little evidence for exposed water ice on the surface. Water ice, if present, must be covered with organic compounds to the depth probed by 1–5‐μm photons: a few millimeters to centimeters.
Journal Article
Environmental Health Practice: An Identity in Crisis
Environmental health practice is facing an identity crisis. Not because our work lacks impact, but because our work lacks a coherent narrative. Environmental health practice needs a brand that speaks our truth and secures our place in the future of health protection. The brand of environmental health practice must be more than a label. It needs to be an asset that our industry can leverage to build identity, recognisability, credibility, relevance and a unique value proposition. A strong brand will allow us to express the unique impact of our role and thus, it needs to capture the most central component of our work that unmistakably differentiates it from anything else. A rapid review of the literature was performed using systematic methods to discern a coherent narrative capturing the essence of environmental health practice. Through application of a critical lens shaped through professional experience, a novel narrative was synthesized of the key defining component of our work. This narrative establishes the work of environmental health practitioners as a unique value proposition and forms the basis for a brand that we can fearlessly project and reverberate. It represents the makings for an unmistakable identity. The future of environmental health practice depends on environmental health practitioners establishing a brand by building awareness of the unique value of our work.
Journal Article
The Adjacency Effect at Kivu Lacus
Observations of high-contrast scenes through an atmosphere are subject to the adjacency effect—the artificial brightening from photons that have scattered in the atmosphere such that they appear to originate from the dark rather rather than the bright surface. In this work, we examine how the adjacency effect manifests in imaging of the surface of Titan, Saturn’s largest moon, through the example case of a particularly high spatial resolution observation of a 100 km lake at Titan’s north pole, Kivu Lacus. We find that the adjacency effect can increase the brightness of dark surfaces up to 10% at 5 μ m, while observations at 2 μ m may be brightened up to 1%. Shorter wavelengths are so dominated by multiple scattering that all directionality is lost; atmospheric scattering swamps any observable adjacency effect. The bidirectional reflectance distribution function modifies both the directionality and magnitude of the adjacency effect, maximizing the effect in the downsun direction for specular surfaces. High-resolution observations (∼1 km) of high-contrast scenes on Titan will need to take into account the adjacency effect at 2 μ m, but the effects at longer wavelengths (or at lower atmospheric opacity) may be smaller than the pixel scale such that observed reflectance heterogeneities are more likely due to actual properties of the surface.
Journal Article
Titan: Earth-like on the Outside, Ocean World on the Inside
Thanks to the Cassini–Huygens mission, Titan, the pale orange dot of Pioneer and Voyager encounters, has been revealed to be a dynamic, hydrologically shaped, organic-rich ocean world offering unparalleled opportunities to explore prebiotic chemistry. And while Cassini–Huygens revolutionized our understanding of each of the three “layers” of Titan—the atmosphere, the surface, and the interior—we are only beginning to hypothesize how these realms interact. In this paper, we summarize the current state of Titan knowledge and discuss how future exploration of Titan would address some of the next decade’s most compelling planetary science questions. We also demonstrate why exploring Titan, both with and beyond the Dragonfly New Frontiers mission, is a necessary and complementary component of an Ocean Worlds Program that seeks to understand whether habitable environments exist elsewhere in our solar system.
Journal Article