2,682 research outputs found
Branding Access Through the Carolina Covenant: Fostering Institutional Image and Brand
The study demonstrates the ability of financial aid to serve as a key component of institutional image and improve a university’s competitive position while also ensuring the access benefits inherent in supporting low-income students. The implications of this work provide an additional rationale for increasing financial aid budgets and substantiate proof of the market’s ability to improve access
The effect of drying on timber frame connections post flooding
Timber structures face a unique risk from flooding. Elevations in moisture content due to prolonged wetting will lead to a reduction in the mechanical properties of the building. Despite recent growth of timber construction in the UK and a known increased risk from flooding, little research has been conducted into its effects on light frame timber construction and the most efficacious drying method. This paper presents the results of experiments to determine the optimum drying conditions for light timber frame construction with oriented strand board sheathing after simulated flooding. A series of specimens were wetted for 5 d to simulate flooding before exposure to different environments. The specimens were load tested and values of ultimate strength, yield strength and stiffness were compared to those of un-wetted control specimens. It was found that the optimum drying condition for recovery of the maximum pre-wetting mechanical properties was an environment of 38°C and 40% relative humidity. Although this is an optimal setting there is still a permanent reduction in the mechanical properties of approximately 40% for strengths and 20% for stiffness. Stiffness is dependent on grain orientation; however, strength was found to be independent of grain orientation, as it is governed by the oriented strand board failure
New Tests for Disruption Mechanisms of Star Clusters: The Large and Small Magellanic Clouds
We compare the observed bivariate distribution of masses(M) and ages(t) of
star clusters in the LMC with the predicted distributions g(M,t) from 3
idealized models for the disruption of star clusters: (1)sudden mass-dependent
disruption;(2)gradual mass-dependent disruption; and (3)gradual
mass-independent disruption. The model with mass-{\em in}dependent disruption
provides a good, first-order description of these cluster populations, with
g(M,t) propto M^{beta} t^{gamma}, beta=-1.8+/-0.2 and gamma=-0.8+/-0.2, at
least for clusters with ages t<10^9 yr and masses M<10^3 M_sol (more
specifically, t<10^7(M/10^2 M_sol)^{1.3} yr). This model predicts that the
clusters should have a power-law luminosity function, dN/dL propto L^-1.8, in
agreement with observations. The first two models, on the other hand, fare
poorly when describing the observations, refuting previous claims that
mass-dependent disruption of star clusters is observed in the LMC over the
studied M-t domain. Clusters in the SMC can be described by the same g(M,t)
distribution as for the LMC, but with smaller samples and hence larger
uncertainties. The successful g(M,t) model for clusters in the Magellanic
Clouds is virtually the same as the one for clusters in the merging Antennae
galaxies, but extends the domain of validity to lower masses and to older ages.
This indicates that the dominant disruption processes are similar in these very
different galaxies over at least t<10^8 yr and possibly t<10^9 yr. The mass
functions for young clusters in the LMC are power-laws, while that for ancient
globular clusters is peaked. We show that the observed shapes of these mass
functions are consistent with expectations from the simple evaporation model
presented by McLaughlin & Fall.Comment: 46 pages, 17 figures, published ApJ, vol 711, page 126
The Globular Cluster Systems around NGC 3311 and NGC 3309
We present extensive new photometry in (g',i') of the large globular cluster
(GC) system around NGC 3311, the central cD galaxy in the Hydra cluster. Our
GMOS data cover a 5.5' field of view and reach a limiting magnitude i' = 26,
about 0.5 magnitude fainter than the turnover point of the GC luminosity
function. We find that NGC 3311 has a huge population of ~16, 000 GCs, closely
similar to the prototypical high specific frequency Virgo giant M87. The
color-magnitude distribution shows that the metal-poor blue GC sequence and the
metal-richer red sequence are both present, with nearly equal numbers of
clusters. Bimodal fits to the color distributions confirm that the blue
sequence shows the same trend of progressively increasing metallicity with GC
mass that has previously been found in many other large galaxies; the
correlation we find corresponds to a scaling of GC metallicity with mass of Z ~
M^0.6 . By contrast, the red sequence shows no change of mean metallicity with
mass, but it shows an upward extension to much higher than normal luminosity
into the UCD-like range, strengthening the potential connections between
massive GCs and UCDs. The GC luminosity function, which we measure down to the
turnover point at M_I = -8.4, also has a normal form like those in other giant
ellipticals. Within the Hydra field, another giant elliptical NGC 3309 is
sitting just 100" from the cD NGC 3311. We use our data to solve simultaneously
for the spatial structure and total GC populations of both galaxies at once.
Their specific frequencies are S_N (NGC 3311) = 12.5 +/- 1.5 and S_N (NGC 3309)
= 0.6 +/-0.4. NGC 3311 is completely dominant and entirely comparable with
other cD-type systems such as M87 in Virgo.Comment: 15 pages, 15 figures. Accepted to the Astrophysical Journal. Version
with higher resolution figures is available at
http://www.thewehners.net/astro/papers/wehner_n3311_highres.pd
Ranking Templates for Linear Loops
We present a new method for the constraint-based synthesis of termination
arguments for linear loop programs based on linear ranking templates. Linear
ranking templates are parametrized, well-founded relations such that an
assignment to the parameters gives rise to a ranking function. This approach
generalizes existing methods and enables us to use templates for many different
ranking functions with affine-linear components. We discuss templates for
multiphase, piecewise, and lexicographic ranking functions. Because these
ranking templates require both strict and non-strict inequalities, we use
Motzkin's Transposition Theorem instead of Farkas Lemma to transform the
generated -constraint into an -constraint.Comment: TACAS 201
A Comparison of Methods for Determining the Age Distribution of Star Clusters: Application to the Large Magellanic Cloud
The age distribution of star clusters in nearby galaxies plays a crucial role
in evaluating the lifetimes and disruption mechanisms of the clusters. Two very
different results have been found recently for the age distribution chi(t) of
clusters in the Large Magellanic Cloud (LMC). We found that chi(t) can be
described approximately by a power law chi(t) propto t^{gamma}, with gamma
-0.8, by counting clusters in the mass-age plane, i.e., by constructing chi(t)
directly from mass-limited samples. Gieles & Bastian inferred a value of
gamma~, based on the slope of the relation between the maximum mass of clusters
in equal intervals of log t, hereafter the M_max method, an indirect technique
that requires additional assumptions about the upper end of the mass function.
However, our own analysis shows that the M_max method gives a result consistent
with our direct counting method for clusters in the LMC, namely chi(t) propto
t^-0.8 for t<10^9 yr. The reason for the apparent discrepancy is that our
analysis includes many massive (M>1.5x10^3 M_sol), recently formed (t<10^7 yr)
clusters, which are known to exist in the LMC, whereas Gieles & Bastian are
missing such clusters. We compile recent results from the literature showing
that the age distribution of young star clusters in more than a dozen galaxies,
including dwarf and giant galaxies, isolated and interacting galaxies,
irregular and spiral galaxies, has a similar declining shape. We interpret this
approximately "universal" shape as due primarily to the progressive disruption
of star clusters over their first ~few x 10^8 yr, starting soon after
formation, and discuss some observational and physical implications of this
early disruption for stellar populations in galaxies.Comment: 21 pages, 5 figures, published in the Astrophysical Journal, volume
713, page 134
Globular Cluster Systems in Brightest Cluster Galaxies: Bimodal Metallicity Distributions and the Nature of the High-Luminosity Clusters
We present new (B,I) photometry for the globular cluster systems in eight
Brightest Cluster Galaxies (BCGs), obtained with the ACS/WFC camera on the
Hubble Space Telescope. In the very rich cluster systems that reside within
these giant galaxies, we find that all have strongly bimodal color
distributions All the BCGs show population gradients, with much higher relative
numbers of red clusters within 5 kpc of their centers, consistent with their
having formed at later times than the blue, metal-poor population. A striking
new feature of the color distributions emerging from our data is that for the
brightest clusters (M_I < -10.5) the color distribution becomes broad and less
obviously bimodal. we suggest that it may be a characteristic of many BCGs.
Furthermore, the blue (metal-poor) clusters become progressively redder with
increasing luminosity, following a mass/metallicity scaling relation Z ~
M^0.55. We argue that these GCS characteristics are consistent with a
hierarchical-merging formation picture in which the metal-poor clusters formed
in protogalactic clouds or dense starburst complexes with gas masses in the
range 10^7 - 10^10 M_Sun, but where the more massive clusters on average formed
in bigger clouds with deeper potential wells where more pre-enrichment could
occur.Comment: 48 pages, 24 Figures, PDF, Submitted to Astrophys.J. and refereed.
For complete pdf file with better figures, see:
http://physwww.mcmaster.ca/%7Eharris/Preprints.htm
In-situ velocity imaging of ultracold atoms using slow--light
The optical response of a moving medium suitably driven into a slow-light
propagation regime strongly depends on its velocity. This effect can be used to
devise a novel scheme for imaging ultraslow velocity fields. The scheme turns
out to be particularly amenable to study in-situ the dynamics of collective and
topological excitations of a trapped Bose-Einstein condensate. We illustrate
the advantages of using slow-light imaging specifically for sloshing
oscillations and bent vortices in a stirred condensate
Soccer Team Vectors
In this work we present STEVE - Soccer TEam VEctors, a principled approach
for learning real valued vectors for soccer teams where similar teams are close
to each other in the resulting vector space. STEVE only relies on freely
available information about the matches teams played in the past. These vectors
can serve as input to various machine learning tasks. Evaluating on the task of
team market value estimation, STEVE outperforms all its competitors. Moreover,
we use STEVE for similarity search and to rank soccer teams.Comment: 11 pages, 1 figure; This paper was presented at the 6th Workshop on
Machine Learning and Data Mining for Sports Analytics at ECML/PKDD 2019,
W\"urzburg, Germany, 201
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