260 research outputs found
Hypocholesterolemic Effects of Nutraceuticals Produced from the Red Microalga Porphyridium sp in Rats
Red microalgae contain functional sulfated polysaccharides (containing dietary fibers), polyunsaturated fatty acids, zeaxanthin, vitamins, minerals, and proteins. Studies in rat models support the therapeutic properties of algal biomass and isolated polysaccharides. Algal products incorporated into rat diets were found to significantly improve total serum cholesterol, serum triglycerides, hepatic cholesterol levels, HDL/LDL ratios and increased fecal excretion of neutral sterols and bile acids. Morphological and metabolic changes were induced by consumption of algal products. These results suggest that red microalgae can be used as potent hypocholesterolemic agents, and they support the potential use of red microalgae as novel nutraceuticals
Revealing Asymmetries in the HD181327 Debris Disk: A Recent Massive Collision or Interstellar Medium Warping
New multi-roll coronagraphic images of the HD181327 debris disk obtained using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope reveal the debris ring in its entirety at high signal-to-noise ratio and unprecedented spatial resolution. We present and apply a new multi-roll image processing routine to identify and further remove quasi-static point-spread function-subtraction residuals and quantify systematic uncertainties. We also use a new iterative image deprojection technique to constrain the true disk geometry and aggressively remove any surface brightness asymmetries that can be explained without invoking dust density enhancements/ deficits. The measured empirical scattering phase function for the disk is more forward scattering than previously thought and is not well-fit by a Henyey-Greenstein function. The empirical scattering phase function varies with stellocentric distance, consistent with the expected radiation pressured-induced size segregation exterior to the belt. Within the belt, the empirical scattering phase function contradicts unperturbed debris ring models, suggesting the presence of an unseen planet. The radial profile of the flux density is degenerate with a radially varying scattering phase function; therefore estimates of the ring's true width and edge slope may be highly uncertain.We detect large scale asymmetries in the disk, consistent with either the recent catastrophic disruption of a body with mass greater than 1% the mass of Pluto, or disk warping due to strong interactions with the interstellar medium
Probing for Exoplanets Hiding in Dusty Debris Disks: Disk Imaging, Characterization, and Exploration with HST/STIS Multi-Roll Coronagraphy
Spatially resolved scattered-light images of circumstellar (CS) debris in
exoplanetary systems constrain the physical properties and orbits of the dust
particles in these systems. They also inform on co-orbiting (but unseen)
planets, systemic architectures, and forces perturbing starlight-scattering CS
material. Using HST/STIS optical coronagraphy, we have completed the
observational phase of a program to study the spatial distribution of dust in
ten CS debris systems, and one "mature" protoplanetrary disk all with HST
pedigree, using PSF-subtracted multi-roll coronagraphy. These observations
probe stellocentric distances > 5 AU for the nearest stars, and simultaneously
resolve disk substructures well beyond, corresponding to the giant planet and
Kuiper belt regions in our Solar System. They also disclose diffuse very
low-surface brightness dust at larger stellocentric distances. We present new
results inclusive of fainter disks such as HD92945 confirming, and better
revealing, the existence of a narrow inner debris ring within a larger diffuse
dust disk. Other disks with ring-like sub-structures, significant asymmetries
and complex morphologies include: HD181327 with a posited spray of ejecta from
a recent massive collision in an exo-Kuiper belt; HD61005 suggested interacting
with the local ISM; HD15115 & HD32297, discussed also in the context of
environmental interactions. These disks, and HD15745, suggest debris system
evolution cannot be treated in isolation. For AU Mic's edge-on disk,
out-of-plane surface brightness asymmetries at > 5 AU may implicate one or more
planetary perturbers. Time resolved images of the MP Mus proto-planetary disk
provide spatially resolved temporal variability in the disk illumination. These
and other new images from our program enable direct inter-comparison of the
architectures of these exoplanetary debris systems in the context of our own
Solar System.Comment: 109 pages, 43 figures, accepted for publication in the Astronomical
Journa
Searching for z~7.7 Lyman Alpha Emitters in the COSMOS Field with NEWFIRM
The study of Ly-alpha emission in the high-redshift universe is a useful
probe of the epoch of reionization, as the Ly-alpha line should be attenuated
by the intergalactic medium (IGM) at low to moderate neutral hydrogen
fractions. Here we present the results of a deep and wide imaging search for
Ly-alpha emitters in the COSMOS field. We have used two ultra-narrowband
filters (filter width of ~8-9 {\deg}A) on the NEWFIRM camera, installed on the
Mayall 4m telescope at Kitt Peak National Observatory, in order to isolate
Ly-alpha emitters at z = 7.7; such ultra-narrowband imaging searches have
proved to be excellent at detecting Ly-alpha emitters. We found 5-sigma
detections of four candidate Ly-alpha emitters in a survey volume of 2.8 x 10^4
Mpc^3 (total survey area ~760 arcmin^2). Each candidate has a line flux greater
than 8 x 10^-18 erg s^-1 cm^-2. Using these results to construct a luminosity
function and comparing to previously established Ly-alpha luminosity functions
at z = 5.7 and z = 6.5, we find no conclusive evidence for evolution of the
luminosity function between z = 5.7 and z = 7.7. Statistical Monte Carlo
simulations suggest that half of these candidates are real z = 7.7 targets, and
spectroscopic follow-up will be required to verify the redshift of these
candidates. However, our results are consistent with no strong evolution in the
neutral hydrogen fraction of the IGM between z = 5.7 and z = 7.7, even if only
one or two of the z = 7.7 candidates are spectroscopically confirmed.Comment: 29 pages, 5 figures, accepted to ApJ (12/11
The Student Movement Volume 107 Issue 11: Have a Merry Christmas! XOXO, The Student Movement
HUMANS
Coping with Finals, Solana Campbell
Meet Jea Erazo, AUSA Public Relations Officer. Interviewed by: Caryn Cruz
Remembering Sharon Dudgeon, Grace No
Women in STEM: Olivia Joyce, Interviewed by: Gloria Oh
ARTS & ENTERTAINMENT
Football Sunday, Nathaniel Reid, Skylor Stark
Student Picks: Christmas Classics, Ysabelle Fernando
NEWS
AFIA x MLS Christmas Party, Ceiry Flores
Boycotts and Bans at the Qatar World Cup, Hannah Cruse
In Loving Memory of Seth Williams, Gloria Oh
IDEAS
How Do We Address Queer Violence?, Alexander J. Hess
Is Reality Really Real When You Aren\u27t Really Looking?, Alexander Navarro
Reflecting on Christmas Traditions, Rachel Ingram-Clay
The New Era of Book Bans, Elizabeth Getahun
Why is Everyone so Happy During Christmastime?, Kayla-Hope Bruno
PULSE
Bon Appétit and the Threat to Cultural Autonomy, Wambui Karanja
It\u27s OrnaMEANT to be a Wonderful Christmastime, Lexie Dunham
It\u27s the Most Stressful Time of the Year, Reagan McCain
Qatar Controversy: The Shadow Behind the World Cup, Melissa Moore
Reflections on the Semester and Plans for Break, Elizabeth Dovich
LAST WORD
A Student Movement Christmas, The Student Movement Staffhttps://digitalcommons.andrews.edu/sm-107/1010/thumbnail.jp
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