120 research outputs found
Matthew Fitzsimmons, Trumpet
Fantasy for Trumpet / Malcolm Arnold; Oboe Concerto in Eb Major / Vincenzo Bellini; Legend / Georges Enescu; Concerto for Trumpet / Aleksandra Pakhmutova; Toccata and Fugue in D minor /J.S. Bach; arr. Frederick Mill
Rediscovering Nature - Daylighting an Urban Stream (Gwynns Run, Baltimore, MD)
This thesis explores through urban design and architecture the relationship between nature and the city. The goals of this thesis are to restore (daylighting) a buried urban stream, the Gwynns Run; reduce the impact of runoff; and create an Urban Ecological Center that fosters environmental stewardship and organizational collaboration.
The Gwynns Run area of study is located in a deteriorating industrial and residential region of southwest Baltimore. The stream flows underground, below underutilized industrial buildings and a strip commercial retail center. Daylighting the stream will serve as a focus for urban renewal for adjacent neighborhoods.
The proposed ecological center will serve as a cornerstone in the urban design strategy of restoring the Gwynns Run. The center's program will exhibit and advocate for stewardship for the reclaimed watershed. The facilities will support the needs of the community, non-profit organizations and the Baltimore Ecosystem Studies (BES)
MRAPs, Irregular Warfare, and Pentagon Reform
The controversial MRAPs raise two questions. First, does the MRAP experience support the contention that the Pentagon is not sufficiently able to field irregular warfare capabilities? Second, what factors best explain the MRAP failure, whether that failure is determined to be their delayed fielding or the fact that they were fielded at all? We conclude that MRAPs are a valid irregular warfare requirement and that the Pentagon should have been better prepared to field them, albeit not on the scale demanded by events in Iraq. We also argue that the proximate cause of the failure to quickly field MRAPs is not the Pentagon’s acquisition system but rather the requirements process, reinforced by more fundamental organizational factors. These findings suggest that acquisition reform is the wrong target for advancing Secretary Gates’ objective of improving irregular warfare capabilities, and that achieving the objective will require more extensive reforms than many realize
Extreme asteroids in the Pan-STARRS 1 Survey
Using the first 18 months of the Pan-STARRS 1 survey we have identified 33
candidate high-amplitude objects for follow-up observations and carried out
observations of 22 asteroids. 4 of the observed objects were found to have
observed amplitude mag. We find that these high amplitude
objects are most simply explained by single rubble pile objects with some
density-dependent internal strength, allowing them to resist mass shedding even
at their highly elongated shapes. 3 further objects although below the cut-off
for 'high-amplitude' had a combination of elongation and rotation period which
also may require internal cohesive strength, depending on the density of the
body. We find that none of the 'high-amplitude asteroids' identified here
require any unusual cohesive strengths to resist rotational fission. 3
asteroids were sufficiently observed to allow for shape and spin pole models to
be determined through light curve inversion. 45864 was determined to have
retrograde rotation with spin pole axes and asteroid 206167 was found to have best fit spin
pole axes , . An additional
object not initially measured with mag, 49257, was determined to
have a shape model which does suggest a high-amplitude object. Its spin pole
axes were best fit for values .
In the course of this project to date no large super-fast rotators ( h) have been identified.Comment: 31 pages; accepted by A
Col-OSSOS: Colors of the Interstellar Planetesimal 1I/`Oumuamua
The recent discovery by Pan-STARRS1 of 1I/2017 U1 (`Oumuamua), on an unbound
and hyperbolic orbit, offers a rare opportunity to explore the planetary
formation processes of other stars, and the effect of the interstellar
environment on a planetesimal surface. 1I/`Oumuamua's close encounter with the
inner Solar System in 2017 October was a unique chance to make observations
matching those used to characterize the small-body populations of our own Solar
System. We present near-simultaneous g, r, and J photometry
and colors of 1I/`Oumuamua from the 8.1-m Frederick C. Gillett Gemini North
Telescope, and photometry from the 4.2 m William Herschel Telescope. Our
grJ observations are directly comparable to those from the
high-precision Colours of the Outer Solar System Origins Survey (Col-OSSOS),
which offer unique diagnostic information for distinguishing between outer
Solar System surfaces. The J-band data also provide the highest signal-to-noise
measurements made of 1I/`Oumuamua in the near-infrared. Substantial, correlated
near-infrared and optical variability is present, with the same trend in both
near-infrared and optical. Our observations are consistent with 1I/`Oumuamua
rotating with a double-peaked period of hours and being a
highly elongated body with an axial ratio of at least 5.3:1, implying that it
has significant internal cohesion. The color of the first interstellar
planetesimal is at the neutral end of the range of Solar System and
solar-reflectance colors: it is like that of some dynamically excited objects
in the Kuiper belt and the less-red Jupiter Trojans.Comment: Accepted to ApJ
Siderophore-Based Microbial Adaptations to Iron Scarcity Across the Eastern Pacific Ocean
Nearly all iron dissolved in the ocean is complexed by strong organic ligands of unknown composition. The effect of ligand composition on microbial iron acquisition is poorly understood, but amendment experiments using model ligands show they can facilitate or impede iron uptake depending on their identity. Here we show that siderophores, organic compounds synthesized by microbes to facilitate iron uptake, are a dynamic component of the marine ligand pool in the eastern tropical Pacific Ocean. Siderophore concentrations in iron-deficient waters averaged 9 pM, up to fivefold higher than in iron-rich coastal and nutrient-depleted oligotrophic waters, and were dominated by amphibactins, amphiphilic siderophores with cell membrane affinity. Phylogenetic analysis of amphibactin biosynthetic genes suggests that the ability to produce amphibactins has transferred horizontally across multiple Gammaproteobacteria, potentially driven by pressures to compete for iron. In coastal and oligotrophic regions of the eastern Pacific Ocean, amphibactins were replaced with lower concentrations (1-2 pM) of hydrophilic ferrioxamine siderophores. Our results suggest that organic ligand composition changes across the surface ocean in response to environmental pressures. Hydrophilic siderophores are predominantly found across regions of the ocean where iron is not expected to be the limiting nutrient for the microbial community at large. However, in regions with intense competition for iron, some microbes optimize iron acquisition by producing siderophores that minimize diffusive losses to the environment. These siderophores affect iron bioavailability and thus may be an important component of the marine iron cycle
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