1,813 research outputs found
Parker and Usery: Portended Constitutional Limits on the Federal Interdiction of Anticompetitive State Action
This Article examines in detail the policies underlying these recent Supreme Court decisions interpreting the Sherman Act and shows that they have equal applicability to FTC enforcement of the Clayton and FTC Acts. The Article identifies the factual criteria used by the courts for distinguishing state and private conduct that is subject to the antitrust laws, and to congressional commerce dictates, from sovereign state regulatory conduct that is immune from antitrust sanction. The Article then focuses on the impact of Usery, which provides constitutional support for the so-called state action doctrine that was originated in Parker v. Brown. Finally, we conclude that the state action doctrine is not limited to the confines of the Sherman, Clayton, or FTC Acts but may well stand as a constitutional limitation on the substantive, economic powers of Congress and its regulatory agencies
Long-range interactions and the sign of natural amplitudes in two-electron systems
In singlet two-electron systems the natural occupation numbers of the
one-particle reduced density matrix are given as squares of the natural
amplitudes which are defined as the expansion coefficients of the two-electron
wave function in a natural orbital basis. In this work we relate the sign of
the natural amplitudes to the nature of the two-body interaction. We show that
long-range Coulomb-type interactions are responsible for the appearance of
positive amplitudes and give both analytical and numerical examples that
illustrate how the long-distance structure of the wave function affects these
amplitudes. We further demonstrate that the amplitudes show an avoided crossing
behavior as function of a parameter in the Hamiltonian and use this feature to
show that these amplitudes never become zero, except for special interactions
in which infinitely many of them can become zero simultaneously when changing
the interaction strength. This mechanism of avoided crossings provides an
alternative argument for the non-vanishing of the natural occupation numbers in
Coulomb systems.Comment: 10 pages, 4 figure
Macrophages from gut-corrected CF mice express human CFTR and lack a pro-inflammatory phenotype
Macrophages represent prominent immune orchestrators of cystic fibrosis (CF) inflammation and, as such, are an ever-increasing focus of CF research with several reports of intrinsic immune dysfunction related to loss of CFTR activity in macrophages themselves. Animal models of CF have contributed, in no small part, to a deepening of our understanding of the pathophysiology of the disease and towards therapeutic development. A commonly-used animal model in CF research is the Cftr(tm1Unc) Tg(FABP-hCFTR) mouse, which displays gut-specific expression of a human CFTR transgene in order to rescue the high rate of early mortality in Cftr-null mice associated with severe intestinal obstruction. We find significant variation in the response to inflammatory challenge of patient macrophages and cells derived from the Cftr(tm1Unc) Tg(FABP-hCFTR) mouse and show that macrophages derived from this mouse exhibit aberrant expression of human CFTR. This may contribute to the absence of inflammatory changes in this model
Roads as nitrogen deposition hot spots
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Biogeochemistry 114 (2013): 149-163, doi:10.1007/s10533-013-9847-z.Mobile sources are the single largest source of nitrogen emissions to the atmosphere in
the US. It is likely that a portion of mobile-source emissions are deposited adjacent to roads and
thus not measured by traditional monitoring networks, which were designed to measure longterm
and regional trends in deposition well away from emission sources. To estimate the
magnitude of near-source nitrogen deposition, we measured concentrations of both dissolved
inorganic nitrogen (DIN) and total (inorganic + organic) dissolved nitrogen (TDN) in throughfall
(i.e., the nitrogen that comes through the forest canopy) along transects perpendicular to two
moderately trafficked roads on Cape Cod in Falmouth MA, coupled with measurements of both
DIN and TDN in bulk precipitation made in adjacent open fields at the same transect distances.
We used the TDN throughfall data to estimate total nitrogen deposition, including dry gaseous
nitrogen deposition in addition to wet deposition and dry particle deposition. There was no
difference in TDN in the bulk collectors along the transects at either site; however TDN in the
throughfall collectors was always higher closest to the road and decreased with distance. These
patterns were driven primarily by differences in the inorganic N and not the organic N. Annual throughfall deposition was 8.7 (+0.4) and 6.8 (+0.5) TDN - kg N ha-1 yr-1 at sites 10 m and 150 m
away from the road respectively. We also characterized throughfall away from a non-road edge
(power line right-of-way) to test whether the increased deposition observed near road edges was
due to deposition near emission sources or due to a physical, edge effect causing higher
deposition. The increased deposition we observed near roads was due to increases in inorganic N
especially NH4
+. This increased deposition was not the result of an edge effect; rather it is due to
near source deposition of mobile source emissions. We scaled these results to the entire
watershed and estimate that by not taking into account the effects of increased gaseous N
deposition from mobile sources we are underestimating the amount of N deposition to the
watershed by 13% - 25%.This research was supported by Woods Hole SeaGrant (grant NA06OAR4170021), NSF
IGERT (grant DGE 0221658), an Edna Bailey Sussman Environmental Internship Award from
Cornell University, and a Mellon Foundation award though Cornell University.2014-04-1
Bose-Fermi mixtures in 1D optical superlattices
The zero temperature phase diagram of binary boson-fermion mixtures in
two-colour superlattices is investigated. The eigenvalue problem associated
with the Bose-Fermi-Hubbard Hamiltonian is solved using an exact numerical
diagonalization technique, supplemented by an adaptive basis truncation scheme.
The physically motivated basis truncation allows to access larger systems in a
fully controlled and very flexible framework. Several experimentally relevant
observables, such as the matter-wave interference pattern and the
condensatefraction, are investigated in order to explore the rich phase
diagram. At symmetric half filling a phase similar to the Mott-insulating phase
in a commensurate purely bosonic system is identified and an analogy to recent
experiments is pointed out. Furthermore a phase of complete localization of the
bosonic species generated by the repulsive boson-fermion interaction is
identified. These localized condensates are of a different nature than the
genuine Bose-Einstein condensates in optical lattices.Comment: 18 pages, 9 figure
Loss of the Histone Pre-mRNA Processing Factor Stem-Loop Binding Protein in Drosophila Causes Genomic Instability and Impaired Cellular Proliferation
BACKGROUND:Metazoan replication-dependent histone mRNAs terminate in a conserved stem-loop structure rather than a polyA tail. Formation of this unique mRNA 3' end requires Stem-loop Binding Protein (SLBP), which directly binds histone pre-mRNA and stimulates 3' end processing. The 3' end stem-loop is necessary for all aspects of histone mRNA metabolism, including replication coupling, but its importance to organism fitness and genome maintenance in vivo have not been characterized. METHODOLOGY/PRINCIPAL FINDINGS:In Drosophila, disruption of the Slbp gene prevents normal histone pre-mRNA processing and causes histone pre-mRNAs to utilize the canonical 3' end processing pathway, resulting in polyadenylated histone mRNAs that are no longer properly regulated. Here we show that Slbp mutants display genomic instability, including loss of heterozygosity (LOH), increased presence of chromosome breaks, tetraploidy, and changes in position effect variegation (PEV). During imaginal disc growth, Slbp mutant cells show defects in S phase and proliferate more slowly than control cells. CONCLUSIONS/SIGNIFICANCE:These data are consistent with a model in which changing the 3' end of histone mRNA disrupts normal replication-coupled histone mRNA biosynthesis and alters chromatin assembly, resulting in genomic instability, inhibition of cell proliferation, and impaired development
Spitzer Space Telescope Infrared Imaging and Spectroscopy of the Crab Nebula
We present 3.6, 4.5, 5.8, 8.0, 24, and 70 micron images of the Crab Nebula
obtained with the Spitzer Space Telescope IRAC and MIPS cameras, Low- and
High-resolution Spitzer IRS spectra of selected positions within the nebula,
and a near-infrared ground-based image made in the light of [Fe II]1.644
micron. The 8.0 micron image, made with a bandpass that includes [Ar II]7.0
micron, resembles the general morphology of visible H-alpha and near-IR [Fe II]
line emission, while the 3.6 and 4.5 micron images are dominated by continuum
synchrotron emission. The 24 micron and 70 micron images show enhanced emission
that may be due to line emission or the presence of a small amount of warm dust
in the nebula on the order of less than 1% of a solar mass. The ratio of the
3.6 and 4.5 micron images reveals a spatial variation in the synchrotron power
law index ranging from approximately 0.3 to 0.8 across the nebula. Combining
this information with optical and X-ray synchrotron images, we derive a
broadband spectrum that reflects the superposition of the flatter spectrum jet
and torus with the steeper diffuse nebula, and suggestions of the expected
pileup of relativistic electrons just before the exponential cutoff in the
X-ray. The pulsar, and the associated equatorial toroid and polar jet
structures seen in Chandra and HST images (Hester et al. 2002) can be
identified in all of the IRAC images. We present the IR photometry of the
pulsar. The forbidden lines identified in the high resolution IR spectra are
all double due to Doppler shifts from the front and back of the expanding
nebula and give an expansion velocity of approximately 1264 km/s.Comment: 21 pages, 4 tables, 16 figure
Evaluation of fecal mRNA reproducibility via a marginal transformed mixture modeling approach
<p>Abstract</p> <p>Background</p> <p>Developing and evaluating new technology that enables researchers to recover gene-expression levels of colonic cells from fecal samples could be key to a non-invasive screening tool for early detection of colon cancer. The current study, to the best of our knowledge, is the first to investigate and report the reproducibility of fecal microarray data. Using the intraclass correlation coefficient (ICC) as a measure of reproducibility and the preliminary analysis of fecal and mucosal data, we assessed the reliability of mixture density estimation and the reproducibility of fecal microarray data. Using Monte Carlo-based methods, we explored whether ICC values should be modeled as a beta-mixture or transformed first and fitted with a normal-mixture. We used outcomes from bootstrapped goodness-of-fit tests to determine which approach is less sensitive toward potential violation of distributional assumptions.</p> <p>Results</p> <p>The graphical examination of both the distributions of ICC and probit-transformed ICC (PT-ICC) clearly shows that there are two components in the distributions. For ICC measurements, which are between 0 and 1, the practice in literature has been to assume that the data points are from a beta-mixture distribution. Nevertheless, in our study we show that the use of a normal-mixture modeling approach on PT-ICC could provide superior performance.</p> <p>Conclusions</p> <p>When modeling ICC values of gene expression levels, using mixture of normals in the probit-transformed (PT) scale is less sensitive toward model mis-specification than using mixture of betas. We show that a biased conclusion could be made if we follow the traditional approach and model the two sets of ICC values using the mixture of betas directly. The problematic estimation arises from the sensitivity of beta-mixtures toward model mis-specification, particularly when there are observations in the neighborhood of the the boundary points, 0 or 1. Since beta-mixture modeling is commonly used in approximating the distribution of measurements between 0 and 1, our findings have important implications beyond the findings of the current study. By using the normal-mixture approach on PT-ICC, we observed the quality of reproducible genes in fecal array data to be comparable to those in mucosal arrays.</p
A multimerizing transcription factor of sea urchin embryos capable of looping DNA
SpGCF1 is a recently cloned sea urchin transcription factor that recognizes target sites in several different sea urchin genes. We find that in gel-shift experiments this factor is able to multimerize. A quantitative simulation of the gel-shift results suggests that SpGCF1 molecules that are bound to DNA target sites may also bind to one another, thus associating several DNA probe molecules. SpGCF1 might therefore be able to loop DNA molecules bearing its target sites at distant locations. We demonstrate this prediction by electron microscopy, and using the well-characterized cis-regulatory domain of the CyIIIa cytoskeletal actin gene, we show that the loop conformations predicted from the known SpGCF1 target site locations are actually formed in vitro. We speculate that the multimerization of this factor in vivo may function to bring distant regions of extended regulatory domains into immediate proximity so that they can interact with one another
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