2,738 research outputs found
Cottonwood Racquet Club
The Cottonwood Racquet Club is a private club development located in the Little Kitten Creek region of West Manhattan, Kansas
Testing metallicity indicators at z~1.4 with the gravitationally lensed galaxy CASSOWARY 20
We present X-shooter observations of CASSOWARY 20 (CSWA 20), a star-forming
(SFR ~6 Msol/yr) galaxy at z=1.433, magnified by a factor of 11.5 by the
gravitational lensing produced by a massive foreground galaxy at z=0.741. We
analysed the integrated physical properties of the HII regions of CSWA 20 using
temperature- and density-sensitive emission lines. We find the abundance of
oxygen to be ~1/7 of solar, while carbon is ~50 times less abundant than in the
Sun. The unusually low C/O ratio may be an indication of a particularly rapid
timescale of chemical enrichment. The wide wavelength coverage of X-shooter
gives us access to five different methods for determining the metallicity of
CSWA 20, three based on emission lines from HII regions and two on absorption
features formed in the atmospheres of massive stars. All five estimates are in
agreement, within the factor of ~2 uncertainty of each method. The interstellar
medium of CSWA 20 only partially covers the star-forming region as viewed from
our direction; in particular, absorption lines from neutrals and first ions are
exceptionally weak. We find evidence for large-scale outflows of the
interstellar medium (ISM) with speeds of up 750 km/s, similar to the values
measured in other high-z galaxies sustaining much higher rates of star
formation.Comment: 18 pages, 11 figures, accepted for publication in MNRA
Use of Erythrocyte Measurements to Identify Triploid Saugeyes
The use of erythrocyte size measurements
as a possible alternative to flow cytometry for identifying triploid saugeyes (female walleye Stizostedion vitreum X male sauger S. canadense) was evaluated. Blood
smear preparations were made from 32 heat-shocked saugeyes (1.0-42.7 g; 52-185 mm total length), which consisted of 12 diploids and 20 triploids, as determined
by flow cytometry after blood cells were stained with propidium iodide. The length, width, surface area, and volume of the cell and nucleus of 100 erythrocytes were
determined for each fish. The cell and nuclear dimensions were measured at 1,000X magnification with a calibrated ocular micrometer. Discriminant analysis was
used to distinguish diploids and triploids based on their score profiles. Results showed that triploid saugeyes had
significantly larger erythrocyte cell and nucleus measurements than their diploid counterparts (N = 32; P < 0.0001). Erythrocyte measurements correctly distinguished 93.8% of fish samples as diploids or triploids, but measurements require about 1 h/fish. The potential
applications of this technique for fisheries management and aquaculture are discussed.This research was funded by the Ohio Division
of Wildlife under Federal Aid in Sport Fish Restoration, project F-69-P-5, Fish Management in Ohio
Ethical and methodological issues in engaging young people living in poverty with participatory research methods
This paper discusses the methodological and ethical issues arising from a project that focused on conducting a qualitative study using participatory techniques with children and young people living in disadvantage. The main aim of the study was to explore the impact of poverty on children and young people's access to public and private services. The paper is based on the author's perspective of the first stage of the fieldwork from the project. It discusses the ethical implications of involving children and young people in the research process, in particular issues relating to access and recruitment, the role of young people's advisory groups, use of visual data and collection of data in young people's homes. The paper also identifies some strategies for addressing the difficulties encountered in relation to each of these aspects and it considers the benefits of adopting participatory methods when conducting research with children and young people
Enantioselective Synthesis of Sealutomicin C
The sealutomicins are a family of anthraquinone antibiotics featuring an enediyne (sealutomicin A) or Bergman-cyclized aromatic ring (sealutomicins BāD). Herein we report the development of an enantioselective organocatalytic method for the synthesis of dihydroquinolines and the use of the developed method in the total synthesis of sealutomicin C which features a transannular cyclization of an aryllithium onto a Ī³-lactone as a second key step
Grazing incidence optics designs for future gamma-ray missions
Sensitive nuclear line spectroscopy for observations of prompt emission from supernovae, as well as mapping of remnants has been a primary goal of gamma-ray astrophysics since its inception. A number of key lines lie in the energy band from 10 - 600 keV. In this region of the spectrum, observations have to-date been limited by high background and poor angular resolution. In this paper, we present several designs capable of extending the sensitivity of grazing incidence optics into this energy range. In particular, we discuss a 15 m focal length design for NASA's High-Sensitivity Spectroscopic Imaging Mission concept, as well as a 50 m focal length design which can extend ESA's XEUS mission into this band. We demonstrate that an unprecedented line sensitivity of 10^(-7) cm^(-2) s^(-1) can be achieved for the most important lines in this energy band
The impact of Hurricane Sandy on the shoreface and inner shelf of Fire Island, New York : large bedform migration but limited erosion
Ā© The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution.. The definitive version was published in Continental Shelf Research 98 (2015): 13-25, doi:10.1016/j.csr.2015.03.001.We investigate the impact of superstorm Sandy on the lower shoreface and inner shelf
offshore the barrier island system of Fire Island, NY using before-and-after surveys involving
swath bathymetry, backscatter and CHIRP acoustic reflection data. As sea level rises over the
long term, the shoreface and inner shelf are eroded as barrier islands migrate landward; large
storms like Sandy are thought to be a primary driver of this largely evolutionary process. The
ābeforeā data were collected in 2011 by the U.S. Geological Survey as part of a long-term
investigation of the Fire Island barrier system. The āafterā data were collected in January, 2013,
~two months after the storm. Surprisingly, no widespread erosional event was observed. Rather,
the primary impact of Sandy on the shoreface and inner shelf was to force migration of major
bedforms (sand ridges and sorted bedforms) 10ās of meters WSW alongshore, decreasing in
migration distance with increasing water depth. Although greater in rate, this migratory behavior
is no different than observations made over the 15-year span prior to the 2011 survey.
Stratigraphic observations of buried, offshore-thinning fluvial channels indicate that long-term
erosion of older sediments is focused in water depths ranging from the base of the shoreface
(~13-16 m) to ~21 m on the inner shelf, which is coincident with the range of depth over which
sand ridges and sorted bedforms migrated in response to Sandy. We hypothesize that bedform
migration regulates erosion over these water depths and controls the formation of a widely
observed transgressive ravinement; focusing erosion of older material occurs at the base of the
stoss (upcurrent) flank of the bedforms. Secondary storm impacts include the formation of
ephemeral hummocky bedforms and the deposition of a mud event layer.This work was funded primarily by a rapid response grant from the Jackson
School of Geosciences, The University of Texas/Austi
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