Discussion: “Comparison of Statistical Methods for Assessing Spatial Correlations Between Maps of Different Arterial Properties” (Rowland, E. M., Mohamied, Y., Chooi, K. Y., Bailey, E. L., and Weinberg, P. D., 2015, ASME J. Biomech. Eng., 137(10), p. 101003): An Alternative Approach Using Segmentation Based on Local Hemodynamics

The biological response of living arteries to mechanical forces is an important component of the atherosclerotic process and is responsible, at least in part, for the well-recognized spatial variation in atherosusceptibility in man. Experiments to elucidate this response often generate maps of force and response variables over the arterial surface, from which the force–response relationship is sought. Rowland et al. discussed several statistical approaches to the spatial autocorrelation that confounds the analysis of such maps and applied them to maps of hemodynamic stress and vascular response obtained by averaging these variables in multiple animals. Here, we point out an alternative approach, in which discrete surface regions are defined by the hemodynamic stress levels they experience, and the stress and response in each animal are treated separately. This approach, applied properly, is insensitive to autocorrelation and less sensitive to the effect of confounding hemodynamic variables. The analysis suggests an inverse relation between permeability and shear that differs from that in Rowland et al. Possible sources of this difference are suggested

Electron spin coherence in metallofullerenes: Y, Sc and La@C82

Endohedral fullerenes encapsulating a spin-active atom or ion within a carbon cage offer a route to self-assembled arrays such as spin chains. In the case of metallofullerenes the charge transfer between the atom and the fullerene cage has been thought to limit the electron spin phase coherence time (T2) to the order of a few microseconds. We study electron spin relaxation in several species of metallofullerene as a function of temperature and solvent environment, yielding a maximum T2 in deuterated o-terphenyl greater than 200 microseconds for Y, Sc and La@C82. The mechanisms governing relaxation (T1, T2) arise from metal-cage vibrational modes, spin-orbit coupling and the nuclear spin environment. The T2 times are over 2 orders of magnitude longer than previously reported and consequently make metallofullerenes of interest in areas such as spin-labelling, spintronics and quantum computing.Comment: 5 pages, 4 figure

Effects of Proportions of Dietary Macronutrients on Glucocorticoid Metabolism in Diet-Induced Obesity in Rats

Tissue glucocorticoid levels in the liver and adipose tissue are regulated by regeneration of inactive glucocorticoid by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) and inactivation by 5α- and 5β-reductases. A low carbohydrate diet increases hepatic 11β-HSD1 and reduces glucocorticoid metabolism during weight loss in obese humans. We hypothesized that similar variations in macronutrient proportions regulate glucocorticoid metabolism in obese rats. Male Lister Hooded rats were fed an obesity-inducing ad libitum ‘Western’ diet (37% fat, n = 36) for 22 weeks, then randomised to continue this diet (n = 12) or to switch to either a low carbohydrate (n = 12) or a moderate carbohydrate (n = 12) diet for the final 8 weeks. A parallel lean control group were fed an ad libitum control diet (10% fat, n = 12) throughout. The low and moderate carbohydrate diets decreased hepatic 11β-HSD1 mRNA compared with the Western diet (both 0.7±0.0 vs 0.9±0.1 AU; p<0.01), but did not alter 11β-HSD1 in adipose tissue. 5α-Reductase mRNA was increased on the low carbohydrate compared with the moderate carbohydrate diet. Compared with lean controls, the Western diet decreased 11β-HSD1 activity (1.6±0.1 vs 2.8±0.1 nmol/mcg protein/hr; p<0.001) and increased 5α-reductase and 5β-reductase mRNAs (1.9±0.3 vs 1.0±0.2 and 1.6±0.1 vs 1.0±0.1 AU respectively; p<0.01) in the liver, and reduced 11β-HSD1 mRNA and activity (both p<0.01) in adipose tissue. Although an obesity-inducing high fat diet in rats recapitulates the abnormal glucocorticoid metabolism associated with human obesity in liver (but not in adipose tissue), a low carbohydrate diet does not increase hepatic 11β-HSD1 in obese rats as occurs in humans

UIT Detection of Hot Stars in the Globular Cluster NGC362

We used the Ultraviolet Imaging Telescope during the March 1995 Astro-2 mission to obtain a deep far-UV image of the globular cluster NGC 362, which was formerly thought to have an almost entirely red horizontal branch (HB). 84 hot (T_eff > 8500 K) stars were detected within a radius of 8'.25 of the cluster center. Of these, 43 have FUV magnitudes consistent with HB stars in NGC 362, and at least 34 are cluster members. The number of cluster members is made uncertain by background contamination from blue stars in the Small Magellanic Cloud (SMC). There are six candidate supra-HB stars which have probably evolved from the HB. We discuss the implications of these results for the production of hot blue stars in stellar populations.Comment: 10 pages AASLaTeX including one postscript figure and one compressed bitmap, .jpg format. To appear in Ap. J. Letters. Postscript version also available at http://www.astro.virginia.edu/~bd4r

Low-ionization Line Emission from Starburst Galaxies: A New Probe of Galactic-Scale Outflows

We study the kinematically narrow, low-ionization line emission from a bright, starburst galaxy at z = 0.69 using slit spectroscopy obtained with Keck/LRIS. The spectrum reveals strong absorption in MgII and FeII resonance transitions with Doppler shifts of -200 to -300 km/s, indicating a cool gas outflow. Emission in MgII near and redward of systemic velocity, in concert with the observed absorption, yields a P Cygni-like line profile similar to those observed in the Ly alpha transition in Lyman Break Galaxies. Further, the MgII emission is spatially resolved, and extends significantly beyond the emission from stars and HII regions within the galaxy. Assuming the emission has a simple, symmetric surface brightness profile, we find that the gas extends to distances > ~7 kpc. We also detect several narrow FeII* fine-structure lines in emission near the systemic velocity, arising from energy levels which are radiatively excited directly from the ground state. We suggest that the MgII and FeII* emission is generated by photon scattering in the observed outflow, and emphasize that this emission is a generic prediction of outflows. These observations provide the first direct constraints on the minimum spatial extent and morphology of the wind from a distant galaxy. Estimates of these parameters are crucial for understanding the impact of outflows in driving galaxy evolution.Comment: Submitted to ApJL. 6 pages, 4 figures. Uses emulateapj forma

Five Planets Transiting a Ninth Magnitude Star

The Kepler mission has revealed a great diversity of planetary systems and architectures, but most of the planets discovered by Kepler orbit faint stars. Using new data from the K2 mission, we present the discovery of a five planet system transiting a bright (V = 8.9, K = 7.7) star called HIP 41378. HIP 41378 is a slightly metal-poor late F-type star with moderate rotation (v sin(i) = 7 km/s) and lies at a distance of 116 +/- 18 from Earth. We find that HIP 41378 hosts two sub-Neptune sized planets orbiting 3.5% outside a 2:1 period commensurability in 15.6 and 31.7 day orbits. In addition, we detect three planets which each transit once during the 75 days spanned by K2 observations. One planet is Neptune sized in a likely ~160 day orbit, one is sub-Saturn sized likely in a ~130 day orbit, and one is a Jupiter sized planet in a likely ~1 year orbit. We show that these estimates for the orbital periods can be made more precise by taking into account dynamical stability considerations. We also calculate the distribution of stellar reflex velocities expected for this system, and show that it provides a good target for future radial velocity observations. If a precise orbital period can be determined for the outer Jovian planet through future observations, it will be an excellent candidate for follow-up transit observations to study its atmosphere and measure its oblateness.Comment: Accepted by ApJL. 12 pages, 6 figures, 2 table

Ultraviolet Imaging Observations of the cD Galaxy in Abell 1795: Further Evidence for Massive Star Formation in a Cooling Flow

We present images from the Ultraviolet Imaging Telescope of the Abell 1795 cluster of galaxies. We compare the cD galaxy morphology and photometry of these data with those from existing archival and published data. The addition of a far--UV color helps us to construct and test star formation model scenarios for the sources of UV emission. Models of star formation with rates in the range \sim5-20M_{\sun}yr$^{-1}$ indicate that the best fitting models are those with continuous star formation or a recent ($\sim4$ Myr old) burst superimposed on an old population. The presence of dust in the galaxy, dramatically revealed by HST images complicates the interpretation of UV data. However, we find that the broad--band UV/optical colors of this cD galaxy can be reasonably matched by models using a Galactic form for the extinction law with $E_{B-V}=0.14$. We also briefly discuss other objects in the large UIT field of view.Comment: To appear in the Astrophysical Journal. 14 AAS preprint style pages plus 7 figure

The Ultraviolet Imaging Telescope: Instrument and Data Characteristics

The Ultraviolet Imaging Telescope (UIT) was flown as part of the Astro observatory on the Space Shuttle Columbia in December 1990 and again on the Space Shuttle Endeavor in March 1995. Ultraviolet (1200-3300 Angstroms) images of a variety of astronomical objects, with a 40 arcmin field of view and a resolution of about 3 arcsec, were recorded on photographic film. The data recorded during the first flight are available to the astronomical community through the National Space Science Data Center (NSSDC); the data recorded during the second flight will soon be available as well. This paper discusses in detail the design, operation, data reduction, and calibration of UIT, providing the user of the data with information for understanding and using the data. It also provides guidelines for analyzing other astronomical imagery made with image intensifiers and photographic film.Comment: 44 pages, LaTeX, AAS preprint style and EPSF macros, accepted by PAS

CO\u3csub\u3e2\u3c/sub\u3e Recycling Using Microalgae for the Production of Fuels

CO2 capture and recycle using microalgae was demonstrated at a coal-fired power plant (Duke Energy’s East Bend Station, Kentucky). Using an in-house designed closed loop, vertical tube photobioreactor, Scenedesmus acutus was cultured using flue gas as the CO2 source. Algae productivity of 39 g/(m2 day) in June–July was achieved at significant scale (18,000 L), while average daily productivity slightly in excess of 10 g/(m2 day) was demonstrated in the month of December. A protocol for low-cost algae harvesting and dewatering was developed, and the conversion of algal lipids—extracted from the harvested biomass—to diesel-range hydrocarbons via catalytic deoxygenation was demonstrated. Assuming an amortization period of 10 years, calculations suggest that the current cost of capturing and recycling CO2 using this approach will fall close to $1,600/ton CO2, the main expense corresponding to the capital cost of the photobioreactor system and the associated installation cost. From this it follows that future cost reduction measures should focus on the design of a culturing system which is less expensive to build and install. In even the most optimistic scenario, the cost of algae-based CO2 capture is unlikely to fall below$225/ton, corresponding to a production cost of ~$400/ton biomass. Hence, the value of the algal biomass produced will be critical in determining the overall economics of CO2 capture and recycle