1,785 research outputs found
EXPERIMENTAL STUDIES OF BEHAVIORAL EFFECTS OF MEPROBAMATE ON NORMAL SUBJECTS
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72318/1/j.1749-6632.1957.tb46007.x.pd
Advancing Our Understanding of the Inheritance and Transmission of Pectus Excavatum
Pectus excavatum is the most common congenital chest wall abnormality expressed in children, yet its inheritance is poorly understood. Here we present the first comprehensive assessment of the inheritance of this disorder. After evaluating 48 pedigrees and 56 clinical traits of probands and family members, we find strong evidence of autosomal recessive, genetic control for this disorder. Additionally there is likely more than one pectus disease-associated allele, as well as a relatively large number of disease allele carriers in the human population. Some clinical traits appear important and may serve as reliable indicators for predicting the likelihood of pectus excavatum in children before severe symptoms present. Quantifying sex-ratio bias in probands demonstrates a highly significant male bias associated with pectus excavatum. When combined with pedigree data, sex-bias is indicative of sex-linked, sex-limited, and/or epigenetic control such as X-inactivation, reiterating a point made with pedigrees alone, which is that more than one mutation is likely responsible for this disorder
A Class of Eccentric Binaries with Dynamic Tidal Distortions Discovered with Kepler
We have discovered a class of eccentric binary systems within the Kepler data
archive that have dynamic tidal distortions and tidally-induced pulsations.
Each has a uniquely shaped light curve that is characterized by periodic
brightening or variability at time scales of 4-20 days, frequently accompanied
by shorter period oscillations. We can explain the dominant features of the
entire class with orbitally-varying tidal forces that occur in close, eccentric
binary systems. The large variety of light curve shapes arises from viewing
systems at different angles. This hypothesis is supported by spectroscopic
radial velocity measurements for five systems, each showing evidence of being
in an eccentric binary system. Prior to the discovery of these 17 new systems,
only four stars, where KOI-54 is the best example, were known to have evidence
of these dynamic tides and tidally-induced oscillations. We perform preliminary
fits to the light curves and radial velocity data, present the overall
properties of this class and discuss the work required to accurately model
these systems.Comment: 13 pages, submitted to Ap
A Comparison of Lifetime Implant Strategies for Beef Steers
Lifetime implant strategies were developed and applied to steer calves. The design was intended for evaluating strategies rather than specific implants. Strategies involving increasing potency of products used at common stages of production. Initial implants were administered when calves were approximately 2 mo of age. Implants did not increase BW at weaning or after backgrounding (P \u3e 0.10) although they did increase ADG 5% over non-implanted controls during backgrounding (P \u3c 0.05). The influence of implants on ADG was more pronounced during the finishing phase of production. Implants increased (P \u3c 0.05) finishing phase ADG 18%, DMI 7.2%, and feed efficiency 9.4%. Overall post-weaning ADG increased 12% (P \u3c 0.05) due to implants. Performance results changed when evaluating data on a live versus carcass weight basis due to differences in dressing percent. Increasing potency of the implant strategies caused progressive increases (P \u3c 0.05) in carcass weight and ribeye area. Implanted steers produced fatter carcasses than did non-implanted steers (P \u3c 0.05). There were no advances in skeletal or lean maturity attributable to the potency of the implant strategy. The frequency of carcasses grading Average Choice or better declined with implants. Implant strategies had no relevant influence on shear force. Overall, 12% of carcasses had a shear force \u3e 5.0 kg (undesirable)
The Sloan Digital Sky Survey Reverberation Mapping Project: Velocity Shifts of Quasar Emission Lines
Quasar emission lines are often shifted from the systemic velocity due to
various dynamical and radiative processes in the line-emitting region. The
level of these velocity shifts depends both on the line species and on quasar
properties. We study velocity shifts for the line peaks of various narrow and
broad quasar emission lines relative to systemic using a sample of 849 quasars
from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. The
coadded (from 32 epochs) spectra of individual quasars have sufficient
signal-to-noise ratio (SNR) to measure stellar absorption lines to provide
reliable systemic velocity estimates, as well as weak narrow emission lines.
The sample also covers a large dynamic range in quasar luminosity (~2 dex),
allowing us to explore potential luminosity dependence of the velocity shifts.
We derive average line peak velocity shifts as a function of quasar luminosity
for different lines, and quantify their intrinsic scatter. We further quantify
how well the peak velocity can be measured for various lines as a function of
continuum SNR, and demonstrate there is no systematic bias in the line peak
measurements when the spectral quality is degraded to as low as SNR~3 per SDSS
pixel. Based on the observed line shifts, we provide empirical guidelines on
redshift estimation from [OII]3728, [OIII]5008, [NeV]3426, MgII, CIII],
HeII1640, broad Hbeta, CIV, and SiIV, which are calibrated to provide unbiased
systemic redshifts in the mean, but with increasing intrinsic uncertainties of
46, 56, 119, 205, 233, 242, 400, 415, and 477 km/s, in addition to the
measurement uncertainties. These more realistic redshift uncertainties are
generally much larger than the formal uncertainties reported by the redshift
pipelines for spectroscopic quasar surveys, and demonstrate the infeasibility
of measuring quasar redshifts to better than ~200 km/s with only broad lines.Comment: matched to the published version; minor changes and conclusions
unchange
A Comparison of 1978 and 2006 Peak Pollen Seasons and Sampling Methods in Missoula, Montana
A study was conducted in Missoula, Montana to compare local pollen counts from 1978 with those measured nearly 30 years later in 2006 using two different measurement techniques (Durham gravimetric sampler and a Burkard volumetric sampler). Trends in peak pollen times measured during the spring, summer and autumn, respectively, were compared between the two years by Pearson’s correlation and frequency of occurrence of plant genus. Meteorological conditions were also examined during each of the two study periods.
In comparing the two years, there was a statistically significant linear association between the different counts for the months of April through August, with similar levels of pollen types for any given month. The five predominant pollen types (based on counts) identified in each study were Pinus, Poaceae, Populus, Alnus, and Betula for 2006 and Pinus, Poaceae, Populus, Acer and Artemisia for 1978. In summary most of the genera displayed similar peak pollination timing between the two years, suggesting that results from the Durham (gravimetric) and Burkard (volumetric) sampling methods are comparable when reporting relative frequency of occurrence
The Sloan Digital Sky Survey Reverberation Mapping Project: Ensemble Spectroscopic Variability of Quasar Broad Emission Lines
We explore the variability of quasars in the MgII and Hbeta broad emission
lines and UV/optical continuum emission using the Sloan Digital Sky Survey
Reverberation Mapping project (SDSS-RM). This is the largest spectroscopic
study of quasar variability to date: our study includes 29 spectroscopic epochs
from SDSS-RM over months, containing 357 quasars with MgII and 41 quasars
with Hbeta . On longer timescales, the study is also supplemented with
two-epoch data from SDSS-I/II. The SDSS-I/II data include an additional
quasars with MgII and 572 quasars with Hbeta. The MgII emission line is
significantly variable ( 10% on 100-day timescales), a necessary
prerequisite for its use for reverberation mapping studies. The data also
confirm that continuum variability increases with timescale and decreases with
luminosity, and the continuum light curves are consistent with a damped
random-walk model on rest-frame timescales of days. We compare the
emission-line and continuum variability to investigate the structure of the
broad-line region. Broad-line variability shows a shallower increase with
timescale compared to the continuum emission, demonstrating that the broad-line
transfer function is not a -function. Hbeta is more variable than MgII
(roughly by a factor of ), suggesting different excitation mechanisms,
optical depths and/or geometrical configuration for each emission line. The
ensemble spectroscopic variability measurements enabled by the SDSS-RM project
have important consequences for future studies of reverberation mapping and
black hole mass estimation of quasars.Comment: 20 pages, 25 figures. ApJ accepted: minor revisions following referee
repor
Effective Control of Chronic γ-Herpesvirus Infection by Unconventional MHC Class Ia–Independent CD8 T Cells
Control of virus infection is mediated in part by major histocompatibility complex (MHC) Class Ia presentation of viral peptides to conventional CD8 T cells. Although important, the absolute requirement for MHC Class Ia–dependent CD8 T cells for control of chronic virus infection has not been formally demonstrated. We show here that mice lacking MHC Class Ia molecules (K(b−/−)xD(b−/−) mice) effectively control chronic γ-herpesvirus 68 (γHV68) infection via a robust expansion of β(2)-microglobulin (β(2)-m)-dependent, but CD1d-independent, unconventional CD8 T cells. These unconventional CD8 T cells expressed: (1) CD8αβ and CD3, (2) cell surface molecules associated with conventional effector/memory CD8 T cells, (3) TCRαβ with a significant Vβ4, Vβ3, and Vβ10 bias, and (4) the key effector cytokine interferon-γ (IFNγ). Unconventional CD8 T cells utilized a diverse TCR repertoire, and CDR3 analysis suggests that some of that repertoire may be utilized even in the presence of conventional CD8 T cells. This is the first demonstration to our knowledge that β(2)-m–dependent, but Class Ia–independent, unconventional CD8 T cells can efficiently control chronic virus infection, implicating a role for β(2)-n–dependent non-classical MHC molecules in control of chronic viral infection. We speculate that similar unconventional CD8 T cells may be able to control of other chronic viral infections, especially when viruses evade immunity by inhibiting generation of Class Ia–restricted T cells
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