180 research outputs found
Enumeration of rises and falls by position
AbstractLet π=(π1, π2,…,πn) denote a permutation of Zn = {1, 2,…, n}. The pair (πi, πi+1) is a rise if πi<πi+1 or a fall if πi>πi+1. Also a conventional rise is counted at the beginning of π and a conventional fall at the end. Let k be a fixed integer ≥ 1. The rise πi,πi+1 is said to be in a in a j (mod k) position if i ≡ j (mod k); similarly for a fall. The conventional rise at the beginning is in a 0 (mod k) position, while the conventional fall at the end is in an n (mod k) position. Let Pn≡Pn(r0,…,rk−1,ƒ0,…,ƒ;k−1) denote the number of permutations having ri rises i (mod k) positions and ƒ;i falls in i (mod k) positions. A generating function for Pn is obtained. In particular, for k = 2 the generating function is quite explicit and also, for certain special cases when k = 4
What are the indications for tonsillectomy in children?
Tonsillectomy with or without adenoidectomy is minimally effective when combined with tympanostomy tube placement in preventing recurrent otitis media in the 3 years following surgery. The risks of surgery must be weighed against potential benefit. (Grade of recommendation: B, based on low-quality randomized controlled trials [RCTs]). The evidence supporting tonsillectomy for recurrence of sore throat is controversial. There is insufficient evidence to recommend other potential indications. (Grade of recommendation: C, based on case series.
Dynamically Driven Evolution of the Interstellar Medium in M51
We report the highest-fidelity observations of the spiral galaxy M51 in CO
emission, revealing the evolution of giant molecular clouds (GMCs) vis-a-vis
the large-scale galactic structure and dynamics. The most massive GMCs
(so-called GMAs) are first assembled and then broken up as the gas flow through
the spiral arms. The GMAs and their H2 molecules are not fully dissociated into
atomic gas as predicted in stellar feedback scenarios, but are fragmented into
smaller GMCs upon leaving the spiral arms. The remnants of GMAs are detected as
the chains of GMCs that emerge from the spiral arms into interarm regions. The
kinematic shear within the spiral arms is sufficient to unbind the GMAs against
self-gravity. We conclude that the evolution of GMCs is driven by large-scale
galactic dynamics --their coagulation into GMAs is due to spiral arm streaming
motions upon entering the arms, followed by fragmentation due to shear as they
leave the arms on the downstream side. In M51, the majority of the gas remains
molecular from arm entry through the inter-arm region and into the next spiral
arm passage.Comment: 6 pages, including 3 figures. Accepted, ApJ
Grizzly bear monitoring by the Heiltsuk people as a crucible for First Nation conservation practice
Guided by deeply held cultural values, First Nations in Canada are rapidly regaining legal authority to manage natural resources. We present a research collaboration among academics, tribal government, provincial and federal government, resource managers, conservation practitioners, and community leaders supporting First Nation resource authority and stewardship. First, we present results from a molecular genetics study of grizzly bears inhabiting an important conservation area within the territory of the Heiltsuk First Nation in coastal British Columbia. Noninvasive hair sampling occurred between 2006 and 2009 in the Koeye watershed, a stronghold for grizzly bears, salmon, and Heiltsuk people. Molecular demographic analyses revealed a regionally significant population of bears, which congregate at the Koeye each salmon-spawning season. There was a minimum of 57 individual bears detected during the study period. Results also pointed to a larger than expected source geography for salmon-feeding bears in the study area (\u3e 1000 km²), as well as early evidence of a declining trend in the bear population potentially explained by declining salmon numbers. Second, we demonstrate and discuss the power of integrating scientific research with a culturally appropriate research agenda developed by indigenous people. Guided explicitly by principles from Gvi’ilas or customary law, this research methodology is coupled with Heiltsuk culture, enabling results of applied conservation science to involve and resonate with tribal leadership in ways that have eluded previous scientific endeavors. In this context, we discuss the effectiveness of research partnerships that, from the outset, create both scientific programs and integrated communities of action that can implement change. We argue that indigenous resource management requires collaborative approaches like ours, in which science-based management is embedded within a socially and culturally appropriate context. We emerge not only with a set of guiding principles for resource management by the Heiltsuk, but a broadly applicable strategy that fosters intimacy with traditional lands and resources and provides a powerful engine for conservation
SMA CO(J=6-5) and 435 micron interferometric imaging of the nuclear region of Arp 220
We have used the Submillimeter Array (SMA) to make the first interferometric
observations (beam size ~1") of the 12CO J=6-5 line and 435 micron (690 GHz)
continuum emission toward the central region of the nearby ULIRG Arp 220. These
observations resolve the eastern and western nuclei from each other, in both
the molecular line and dust continuum emission. At 435 micron, the peak
intensity of the western nucleus is stronger than the eastern nucleus, and the
difference in peak intensities is less than at longer wavelengths. Fitting a
simple model to the dust emission observed between 1.3 mm and 435 micron
suggests that dust emissivity power law index in the western nucleus is near
unity and steeper in the eastern nucleus, about 2, and that the dust emission
is optically thick at the shorter wavelength. Comparison with single dish
measurements indicate that the interferometer observations are missing ~60% of
the dust emission, most likely from a spatially extended component to which
these observations are not sensitive. The 12CO J=6-5 line observations clearly
resolve kinematically the two nuclei. The distribution and kinematics of the
12CO J=6-5 line appear to be very similar to lower J CO lies observed at
similar resolution. Analysis of multiple 12CO line intensities indicates that
the molecular gas in both nuclei have similar excitation conditions, although
the western nucleus is warmer and denser. The excitation conditions are similar
to those found in other extreme environments, including M82, Mrk 231, and BR
1202-0725. Simultaneous lower resolution observations of the 12CO, 13CO, and
C18O J=2-1 lines show that the 13CO and C18O lines have similar intensities,
which suggests that both of these lines are optically thick, or possibly that
extreme high mass star formation has produced in an overabundance of C18O.Comment: 13 pages (emulateapj), 10 figures, Accepted for publication in Ap
Estimating Luminosity Function Constraints from High-Redshift Galaxy Surveys
The installation of the Wide Field Camera 3 (WFC3) on the Hubble Space
Telescope (HST) will revolutionize the study of high-redshift galaxy
populations. Initial observations of the HST Ultra Deep Field (UDF) have
yielded multiple z>~7 dropout candidates. Supplemented by the Great Observatory
Origins Deep Survey (GOODS) Early Release Science (ERS) and further UDF
pointings, these data will provide crucial information about the most distant
known galaxies. However, achieving tight constraints on the z~7 galaxy
luminosity function (LF) will require even more ambitious photometric surveys.
Using a Fisher matrix approach to fully account for Poisson and cosmic sample
variance, as well as covariances in the data, we estimate the uncertainties on
LF parameters achieved by surveys of a given area and depth. Applying this
method to WFC3 z~7 dropout galaxy samples, we forecast the LF parameter
uncertainties for a variety of model surveys. We demonstrate that performing a
wide area (~1 deg^2) survey to H_AB~27 depth or increasing the UDF depth to
H_AB~30 provides excellent constraints on the high-z LF when combined with the
existing UDF GO and GOODS ERS data. We also show that the shape of the matter
power spectrum may limit the possible gain of splitting wide area (>~0.5 deg^2)
high-redshift surveys into multiple fields to probe statistically independent
regions; the increased root-mean-squared density fluctuations in smaller
volumes mostly offset the improved variance gained from independent samples.Comment: Version accepted by ApJ
The Grizzly, April 20, 1993
Two Officers Guilty in King Trial • U.C. Tutoring Program Benefits Local Students • Open Your Minds Ursinus: Give Art a Chance • Men\u27s Tennis Ups Record to 5-3 • Better Days on the Diamond • Men\u27s LaX Facing Tough Competitionhttps://digitalcommons.ursinus.edu/grizzlynews/1315/thumbnail.jp
The Grizzly, April 28, 1992
Earth Day 1992: Fun for All • CoreStates Grants Grant • UC History Majors Present Papers • U.C. a hit at U.N. • Holocaust Survivor Speaks • Scholarly Hat Trick in Biology • Political Cartoonist To Speak • Strunk Runs for Office • Spring Weekend Great Success • Concert Band & Jazz Ensemble Perform • Exam Schedule • Student Art Exhibition Opens, Awards Presented • Wismer\u27s Modern Art Spy • First Friends First • Sophomore Chats Tell All • Letter: Strunk Thanks Democrats • Men\u27s Lacrosse Splits Weekendhttps://digitalcommons.ursinus.edu/grizzlynews/1296/thumbnail.jp
Mass of the Southern Black Hole in NGC 6240 from Laser Guide Star Adaptive Optics
NGC 6240 is a pair of colliding disk galaxies, each with a black hole in its
core. We have used laser guide star adaptive optics on the Keck II telescope to
obtain high-resolution (") near-infrared integral-field spectra of
the region surrounding the supermassive black hole in the south nucleus of this
galaxy merger. We use the K-band CO absorption bandheads to trace stellar
kinematics. We obtain a spatial resolution of about 20 pc and thus directly
resolve the sphere of gravitational influence of the massive black hole. We
explore two different methods to measure the black hole mass. Using a Jeans
Axisymmetric Multi-Gaussian mass model, we investigate the limit that a relaxed
mass distribution produces all of the measured velocity dispersion, and find an
upper limit on the black hole mass at 2.0 \pm 0.2 \times 10^9 M_{\sun}. When
assuming the young stars whose spectra we observe remain in a thin disk, we
compare Keplerian velocity fields to the measured two-dimensional velocity
field measured and fit for a mass profile containing a black hole point mass
plus a radially-varying spherical component, which suggests a lower limit for
the black hole mass of 8.7 \pm 0.3 \times 10^8 M_{\sun}. Our measurements of
the stellar velocity dispersion place this AGN within the scatter of the
- relation. As NGC 6240 is a merging system, this may
indicate that the relation is preserved during a merger at least until the
final coalescence of the two nuclei.Comment: 10 pages, 12 figures; accepted to Ap
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