1,948 research outputs found
Understanding Enrollment: Developing a Comprehensive Data File and Conducting Trend Analysis
The purpose of this project was to better understand enrollment trends related to first-year, direct-from-high school applicants for admissions to postsecondary education institutions. Analysis of this trend information could be used to evaluate program effectiveness, to assist in developing award allocation strategies, and to create a historical benchmark for future assessment projects or program evaluations. A secondary purpose of this project was to develop a model for use in conducting assessment and trend analysis projects using other institutions\u27 student populations. To complete this study, a comprehensive data file was developed with specifically selected information from students\u27 records in the admissions, registrar\u27s, and student financial aid offices
A biometrical study of the relationship between sodium-lithium countertransport and triglycerides
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66400/1/j.1469-1809.1997.6120121.x.pd
The intracellular distribution of radioiodine labeled lactogenic hormone in the rabbit mammary gland
The bulletin reports on Department of Dairy Husbandry Research Project 28, 'Hormone Enzymes'--P. [2].Digitized 2007 AES.Includes bibliographical references (pages 46-52)
The Turbulent Magnetic Prandtl Number of MHD Turbulence in Disks
The magnetic Prandtl number Pr_M is the ratio of viscosity to resistivity. In
astrophysical disks the diffusion of angular momentum (viscosity) and magnetic
fields (resistivity) are controlled by turbulence. Phenomenological models of
the evolution of large scale poloidal magnetic fields in disks suggest that the
turbulent magnetic Prandtl number Pr_{M,T} controls the rate of escape of
vertical field from the disk; for Pr_{M,T} leq R/H vertical field diffuses
outward before it can be advected inward by accretion. Here we measure field
diffusion and angular momentum transport due to MHD turbulence in a shearing
box, and thus Pr_{M,T}, by studying the evolution of a sinusoidal perturbation
in the magnetic field that is injected into a turbulent background. We show
that the perturbation is always stable, decays approximately exponentially, has
decay rate proportional to k^2, and that the implied Pr_{M,T} ~ 1.Comment: 15pages, 1 figure, accepted by Ap
Long-term Evolution of Protostellar and Protoplanetary Disks. I. Outbursts
As an initial investigation into the long-term evolution of protostellar
disks, we explore the conditions required to explain the large outbursts of
disk accretion seen in some young stellar objects. We use one-dimensional
time-dependent disk models with a phenomenological treatment of the
magnetorotational instability (MRI) and gravitational torques to follow disk
evolution over long timescales. Comparison with our previous two-dimensional
disk model calculations (Zhu et al. 2009b, Z2009b) indicates that the neglect
of radial effects and two-dimensional disk structure in the one-dimensional
case makes only modest differences in the results; this allows us to use the
simpler models to explore parameter space efficiently. We find that the mass
infall rates typically estimated for low-mass protostars generally result in
AU-scale disk accretion outbursts, as predicted by our previous analysis (Zhu
et al. 2009a,Z2009a). We also confirm quasi-steady accretion behavior for high
mass infall rates if the values of -parameter for the magnetorotational
instability is small, while at this high accretion rate convection from the
thermal instability may lead to some variations. We further constrain the
combinations of the -parameter and the MRI critical temperature, which
can reproduce observed outburst behavior. Our results suggest that dust
sublimation may be connected with full activation of the MRI. This is
consistent with the idea that small dust captures ions and electrons to
suppress the MRI. In a later paper we will explore both long-term outburst and
disk evolution with this model, allowing for infall from protostellar envelopes
with differing angular momenta.Comment: Accepted to publish in Ap
Variation at the M235T locus of the angiotensinogen gene and essential hypertension: a population-based case-control study from Rochester, Minnesota
A variant of the angiotensinogen gene, M235T, has been associated with essential hypertension in selected subjects from Paris, France and Salt Lake City, Utah. In the present report, we studied a population-based sample consisting of 104 subjects diagnosed with hypertension before age 60 and 195 matched normotensive individuals from Rochester, Minnesota. We determined whether there was a relationship between the M235T polymorphism of the angiotensinogen gene and the occurrence of essential hypertension using two methods. First, a contingency chi-square analysis was carried out to test for an association between the M235T polymorphism and hypertension status. Second, multivariable conditional logistic regression was used to determine whether variation at the M235T polymorphism was a significant predictor of the probability of having essential hypertension. We detected no statistically significant association between the M235T polymorphism and the occurrence of essential hypertension. In particular, the association was not significant in either gender or in a subset of severely hypertensive subjects requiring two or more anti-hypertensive medications. Furthermore, variation in the number of M235T alleles did not make a significant contribution to predicting the probability of having essential hypertension, either alone or in conjunction with other predictor variables. These results suggest that the contribution of variation in the angiotensinogen gene to the occurrence of essential hypertension is less than initially suspected, or may not be constant across populations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47639/1/439_2004_Article_BF00210410.pd
Linkage Analysis of Plasma ApoE in Three Ethnic Groups: Multiple Genes with Context-Dependent Effects
We performed variance component-based linkage analysis in four samples (two of non-Hispanic European-Americans from Rochester, MN; African-Americans from Jackson, MS; and Mexican-Americans from Starr County, TX) to identify chromosomal regions containing genes influencing plasma apolipoprotein E (apoE) levels. The APOE gene region on chromosome (chr) 19 was identified with a LOD ≥ 2.00 in both samples from Rochester and the sample from Jackson. Adjustment of apoE levels for differences among means of genotypes defined by the APOE ε2/3/4 alleles reduced evidence of linkage, indicating that the APOE gene was responsible for the majority of the linkage signal. In stratified linkage analyses, there was a LOD of 1.70 in the Starr County sibships with average total cholesterol (TC) above the median level for all sibships in that population. Adjustment for APOE genotype did not remove this LOD score, suggesting a second gene in this region may influence apoE variation. Evidence of linkage ( LOD = 3.32) on chr 17 was observed in the Starr County sibships with average TC below the median. Inter-individual variation in plasma apoE level may be influenced by variations in the structural gene, and at least one other gene whose effects differ among populations and are dependent on the influence of unmeasured genetic and environmental factors indexed by correlated measures of lipid metabolism.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66071/1/j.1469-1809.2004.00148.x.pd
The HST Key Project on the Extragalactic Distance Scale XVII. The Cepheid Distance to NGC 4725
The distance to NGC 4725 has been derived from Cepheid variables, as part of
the Hubble Space Telescope Key Project on the Extragalactic Distance Scale.
Thirteen F555W (V) and four F814W (I) epochs of cosmic-ray-split Wide Field and
Planetary Camera 2 observations were obtained. Twenty Cepheids were discovered,
with periods ranging from 12 to 49 days. Adopting a Large Magellanic Cloud
distance modulus and extinction of 18.50+/-0.10 mag and E(V-I)=0.13 mag,
respectively, a true reddening-corrected distance modulus (based on an analysis
employing the ALLFRAME software package) of 30.50 +/- 0.16 (random) +/- 0.17
(systematic) mag was determined for NGC 4725. The corresponding of distance of
12.6 +/- 1.0 (random) +/- 1.0 (systematic) Mpc is in excellent agreement with
that found with an independent analysis based upon the DoPHOT photometry
package. With a foreground reddening of only E(V-I)=0.02, the inferred
intrinsic reddening of this field in NGC 4725, E(V-I)=0.19, makes it one of the
most highly-reddened, encountered by the HST Key Project, to date.Comment: To be published in The Astrophysical Journal, Vol. 512 (1999). 34
pages, LaTeX, 9 jpg figure
NGC 7582: The Prototype Narrow-Line X-ray Galaxy
NGC 7582 is a candidate prototype of the Narrow Line X-ray Galaxies (NLXGs)
found in deep X-ray surveys. An ASCA observation shows the hard (> 3 keV) X-ray
continuum of NGC 7582 drops 40% in ~6 ks, implying an AGN, while the soft band
(< 3 keV) does not drop in concert with the hard continuum, requiring a
separate component. The X-ray spectrum of NGC 7582 also shows a clear 0.5-2 keV
soft (kT = 0.8 (+0.9,-0.3) keV or Gamma = 2.4 +/- 0.6; L(X) = 6 x 10**40 ergs
s**-1) low--energy component, in addition to a heavily absorbed [N(H) = (6 +/-
2)\times 10**22 cm**-2 ] and variable 2-10 keV power law [Gamma = 0.7
(+0.3,-0.4); L(X) = (1.7-2.3) x 10**42 ergs s**-1]. This is one of the flattest
2-10 keV slopes in any AGN observed with ASCA. (The ROSAT HRI image of NGC 7582
further suggests extent to the SE.)
These observations make it clear that the hard X-ray emission of NGC 7582,
the most "narrow-line" of the NLXGs, is associated with an AGN. The strong
suggestion is that all NLXGs are obscured AGNs, as hypothesized to explain the
X-ray background spectral paradox. The separate soft X-ray component makes NGC
7582 (and by extension other NLXGs) detectable as a ROSAT source.Comment: text: Latex2e 10 pages, including 1 table, and 2 postscript figures
via psfi
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