Coronary computed tomography angiography of spontaneous coronary artery dissection: A case report and review of the literature

Patient: Male, 23 Final Diagnosis: Spontaneous coronary artery dissection Symptoms: Chest discomfort • chest pain Medication: — Clinical Procedure: Coronary computed tomography angiography Specialty: Radiology OBJECTIVE: Rare disease BACKGROUND: Multidetector computed tomography (MDCT) has gained wide acceptance in the evaluation of the cardiovascular system. Of particular clinical interest is its ability to non-invasively evaluate coronary arteries in patients presenting to the emergency room. In acute coronary syndromes, myocardial ischemia is most often caused by atherosclerosis. We present a case of a rare cause of acute coronary syndrome, spontaneous coronary artery dissection (SCAD), which was initially evaluated with MDCT and followed by intravascular ultrasound (IVUS) and invasive coronary angiography (ICA). We discuss the findings and role of each modality with particular attention to coronary computed tomographic angiography (CCTA) in the diagnosis and management of SCAD. As the use of CCTA in the emergency department continues to rise, radiologists must become familiar with CT appearance of SCAD. CASE REPORT: We report the multidetector computed tomography (MDCT), intravascular ultrasound (IVUS), and invasive coronary angiography (ICA) findings in a case of spontaneous coronary artery dissection of the left anterior descending artery in a previously healthy 23-year-old man. The role of coronary computed tomographic angiography (CCTA) in diagnosis and management of this potentially life-threatening condition is discussed. CONCLUSIONS: In the clinical setting of acute coronary syndrome, SCAD must be a consideration, particularly in young patients without clear risk factors for coronary artery disease and in women in the peripartum period. CCTA is a very helpful diagnostic tool to diagnose the condition in a non-invasive manner and to follow up after treatment

Determining the depth of Jupiter's Great Red Spot with Juno: a Slepian approach

One of Jupiter's most prominent atmospheric features, the Great Red Spot (GRS), has been observed for more than two centuries, yet little is known about its structure and dynamics below its observed cloud-level. While its anticyclonic vortex appearance suggests it might be a shallow weather-layer feature, the very long time span for which it was observed implies it is likely deeply rooted, otherwise it would have been sheared apart by Jupiter's turbulent atmosphere. Determining the GRS depth will shed light not only on the processes governing the GRS, but on the dynamics of Jupiter's atmosphere as a whole. The Juno mission single flyby over the GRS (PJ7) discovered using microwave radiometer measurements that the GRS is at least a couple hundred kilometers deep (Li et al. 2017). The next flybys over the GRS (PJ18 and PJ21), will allow high-precision gravity measurements that can be used to estimate how deep the GRS winds penetrate below the cloud-level. Here we propose a novel method to determine the depth of the GRS based on the new gravity measurements and a Slepian function approach that enables an effective representation of the wind-induced spatially-confined gravity signal, and an efficient determination of the GRS depth given the limited measurements. We show that with this method the gravity signal of the GRS should be detectable for wind depths deeper than 300 kilometers, with reasonable uncertainties that depend on depth (e.g., $\pm$100km for a GRS depth of 1000km)

A New Einstein Cross: A Highly Magnified, Intrinsically Faint Lyman-Alpha Emitter at z=2.7

We report the discovery of a new Einstein cross at redshift z_S = 2.701 based on Lyman-alpha emission in a cruciform configuration around an SDSS luminous red galaxy (z_L = 0.331). The system was targeted as a possible lens based on an anomalous emission line in the SDSS spectrum. Imaging and spectroscopy from the W. M. Keck Observatory confirm the lensing nature of this system. This is one of the widest-separation galaxy-scale lenses known, with an Einstein radius of ~1.84 arcsec. We present simple gravitational lens models for the system and compute the intrinsic properties of the lensed galaxy. The total mass of the lensing galaxy within the 8.8 +/- 0.1 kpc enclosed by the lensed images is (5.2 +/- 0.1) x 10^11 M_sun. The lensed galaxy is a low mass galaxy (0.2 L*) with a high equivalent-width Lyman-alpha line (EW_Lya_rest = 46 +/- 5 Angstroms). Follow-up studies of this lens system can probe the mass structure of the lensing galaxy, and can provide a unique view of an intrinsically faint, high-redshift, star-forming galaxy at high signal-to-noise ratio.Comment: ApJ Letters, in pres

Direct Communication to Earth from Probes

A viewgraph presentation on outer planetary probe communications to Earth is shown. The topics include: 1) Science Rational for Atmospheric Probes to the Outer Planets; 2) Controlling the Scientific Appetite; 3) Learning more about Jupiter before we send more probes; 4) Sample Microwave Scan From Juno; 5) Jupiter s Deep Interior; 6) The Square Kilometer Array (SKA): A Breakthrough for Radio Astronomy; 7) Deep Space Array-based Network (DSAN); 8) Probe Direct-to-Earth Data Rate Calculations; 9) Summary; and 10) Enabling Ideas

The Sloan Lens ACS Survey. VI: Discovery and analysis of a double Einstein ring

We report the discovery of two concentric Einstein rings around the gravitational lens SDSSJ0946+1006, as part of the Sloan Lens ACS Survey. The main lens is at redshift zl=0.222, while the inner ring (1) is at zs1=0.609 and Einstein radius $Re_1=1.43\pm0.01"$. The wider image separation ($Re_2=2.07\pm 0.02"$) of the outer ring (2) implies that it is at higher redshift. Its detection in the F814W filter implies zs2<6.9. The configuration can be well described by a total density profile $\rho_{tot} ~ r^-g'$ with $g'=2.00\pm0.03$ and velocity dispersion \sigma_{SIE}=287\pm5\kms. [...] We consider whether this configuration can be used to constrain cosmological parameters exploiting angular distance ratios entering the lens equations. Constraints for SDSSJ0946+1006, are uninteresting due to the sub-optimal lens and source redshifts. We then consider the perturbing effect of the mass associated with Ring 1 building a double lens plane compound lens model. This introduces minor changes to the mass of the main lens and allows to estimate the mass of Ring 1 (\sigma_{SIE,s1}=94\pm30\kms). We examine the prospects of doing cosmography with a sample of 50 double lenses, expected from future space based surveys such as DUNE or JDEM. Taking full account of the model uncertainties, such a sample could be used to measure $\Omega_m$ and $w$ with 10% accuracy, for a flat cosmology

Cabin-fuselage-wing structural design concept with engine installation

The purpose of this project is to provide a fuselage structural assembly and wing structural design that will be able to withstand the given operational parameters and loads provided by Federal Aviation Regulation Part 23 (FAR 23) and the Statement of Work (SOW). The goal is to provide a durable lightweight structure that will transfer the applied loads through the most efficient load path. Areas of producibility and maintainability of the structure will also be addressed. All of the structural members will also meet or exceed the desired loading criteria, along with providing adequate stiffness, reliability, and fatigue life as stated in the SOW. Considerations need to be made for control system routing and cabin heating/ventilation. The goal of the wing structure and carry through structure is also to provide a simple, lightweight structure that will transfer the aerodynamic forces produced by the wing, tailboom, and landing gear. These forces will be channeled through various internal structures sized for the pre-determined loading criteria. Other considerations were to include space for flaps, ailerons, fuel tanks, and electrical and control system routing. The difficulties encountered in the fuselage design include expanding the fuselage cabin to accept a third occupant in a staggered configuration and providing ample volume for their safety. By adding a third person the CG of aircraft will move forward so the engine needs to be moved aft to compensate for the difference in the moment. This required the provisions of a ring frame structure for the new position of the engine mount. The difficulties encountered in the wing structural design include resizing the wing for the increased capacity and weight, and compensating for a large torsion produced by the tail boom by placing a great number of stiffeners inside the boom, which will result in the relocation of the fuel tank. Finally, an adequate carry through structure for the wing and fuselage interface will be designed to effectively transmit loads through the fuselage

Storms and the Depletion of Ammonia in Jupiter: I. Microphysics of “Mushballs”

Microwave observations by the Juno spacecraft have shown that, contrary to expectations, the concentration of ammonia is still variable down to pressures of tens of bars in Jupiter. We show that during strong storms able to loft water ice into a region located at pressures between 1.1 and 1.5 bar and temperatures between 173 and 188 K, ammonia vapor can dissolve into water ice to form a low‐temperature liquid phase containing about one‐third ammonia and two‐third water. We estimate that, following the process creating hailstorms on Earth, this liquid phase enhances the growth of hail‐like particles that we call mushballs. We develop a simple model to estimate the growth of these mushballs, their fall into Jupiter’s deep atmosphere, and their evaporation. We show that they evaporate deeper than the expected water cloud base level, between 5 and 27 bar depending on the assumed abundance of water ice lofted by thunderstorms and on the assumed ventilation coefficient governing heat transport between the atmosphere and the mushball. Because the ammonia is located mostly in the core of the mushballs, it tends to be delivered deeper than water, increasing the efficiency of the process. Further sinking of the condensates is expected due to cold temperature and ammonia‐ and water‐rich downdrafts formed by the evaporation of mushballs. This process can thus potentially account for the measurements of ammonia depletion in Jupiter’s deep atmosphere.Plain Language SummaryThe Juno mission has revealed that Jupiter’s atmosphere is much more complex and intriguing than previously anticipated. Most of Jupiter’s atmosphere was shown to be depleted in ammonia. While ammonia was expected to be well mixed, large scale variability of ammonia was detected at least 100 km below the cloud level where condensation occurs. We propose a mechanism to explain this depletion and variability. We show that in Jupiter, at very low temperatures (of order −90° C), water ice and ammonia vapor combine to form a liquid and we hypothesize that this subsequently triggers unexpected meteorology. During Jupiter’s violent storms, hailstones form from this liquid, similar to the process in terrestrial storms where hail forms in the presence of supercooled liquid water. Growth of the hailstones creates a slush‐like substance surrounded by a layer of ice, and these “mushballs” fall, evaporate, and continue sinking further in the planet’s deep atmosphere, creating both ammonia depletion and variability, potentially explaining the Juno observations.Key PointsWe show that ammonia can melt water‐ice crystals in Jupiter’s storms and lead to the formation of water‐ammonia hailstones (mushballs)These mushballs and subsequent downdrafts transport ammonia to very deep levelsThis can potentially explain Juno measurements that Jupiter’s ammonia abundance is variable until at least 150 km below the visible cloudsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156131/2/jgre21375.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156131/1/jgre21375_am.pd

Sloan Digital Sky Survey Spectroscopic Lens Search. I. Discovery of Intermediate-Redshift Star-Forming Galaxies Behind Foreground Luminous Red Galaxies

We present a catalog of 49 spectroscopic strong gravitational lens candidates selected from a Sloan Digital Sky Survey sample of 50996 luminous red galaxies. Potentially lensed star-forming galaxies are detected through the presence of background oxygen and hydrogen nebular emission lines in the spectra of these massive foreground galaxies. This multiline selection eliminates the ambiguity of single-line identification and provides a very promising sample of candidate galaxy-galaxy lens systems at low to intermediate redshift, with foreground redshifts ranging from 0.16 to 0.49 and background redshifts from 0.25 to 0.81. Any lenses confirmed within our sample would be important new probes of early-type galaxy mass distributions, providing complementary constraints to those obtained from currently known lensed high-redshift quasars.Comment: 23 pages; to appear in The Astronomical Journal, 2004 April. Version with full-resolution figures available at http://web.mit.edu/bolton/www/speclens.ps.gz (PostScript) or http://web.mit.edu/bolton/www/speclens.pdf (PDF

Comparison of the deep atmospheric dynamics of Jupiter and Saturn in light of the Juno and Cassini gravity measurements

The nature and structure of the observed east-west flows on Jupiter and Saturn have been a long-standing mystery in planetary science. This mystery has been recently unraveled by the accurate gravity measurements provided by the Juno mission to Jupiter and the Grand Finale of the Cassini mission to Saturn. These two experiments, which coincidentally happened around the same time, allowed the determination of the overall vertical and meridional profiles of the zonal flows on both planets. This paper reviews the topic of zonal jets on the gas giants in light of the new data from these two experiments. The gravity measurements not only allow the depth of the jets to be constrained, yielding the inference that the jets extend to roughly 3000 and 9000 km below the observed clouds on Jupiter and Saturn, respectively, but also provide insights into the mechanisms controlling these zonal flows. Specifically, for both planets this depth corresponds to the depth where electrical conductivity is within an order of magnitude of 1 S m⁻¹, implying that the magnetic field likely plays a key role in damping the zonal flows. An intrinsic characteristic of any gravity inversion, as discussed here, is that the solutions might not be unique. We analyze the robustness of the solutions and present several independent lines of evidence supporting the results presented here