1,833 research outputs found
Electric dipole moment constraints on minimal electroweak baryogenesis
We study the simplest generic extension of the Standard Model which allows
for conventional electroweak baryogenesis, through the addition of dimension
six operators in the Higgs sector. At least one such operator is required to be
CP-odd, and we study the constraints on such a minimal setup, and related
scenarios with minimal flavor violation, from the null results of searches for
electric dipole moments (EDMs), utilizing the full set of two-loop
contributions to the EDMs. The results indicate that the current bounds are
stringent, particularly that of the recently updated neutron EDM, but fall
short of ruling out these scenarios. The next generation of EDM experiments
should be sufficiently sensitive to provide a conclusive test.Comment: 20 pages, 5 figures; v2: comments added and minor corrections to the
results, published versio
Collecting Virtual and Augmented Reality in the Twenty-First Century Library
In this paper, we discuss possible pedagogical applications for virtual and augmented reality (VR and AR), within a humanities/social sciences curriculum, articulating a critical need for academic libraries to collect and curate 3D objects. We contend that building infrastructure is critical to keep pace with innovative pedagogies and scholarship. We offer theoretical avenues for libraries to build a repository 3D object files to be used in VR and AR tools and sketch some anticipated challenges. To build an infrastructure to support VR/AR collections, we have collaborated with College of Liberal Arts to pilot a program in which Libraries and CLA faculty work together to bring VR/AR into liberal arts curricula
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Parasitic helminths induce fetal-like reversion in the intestinal stem cell niche.
Epithelial surfaces form critical barriers to the outside world and are continuously renewed by adult stem cells1. Whereas dynamics of epithelial stem cells during homeostasis are increasingly well understood, how stem cells are redirected from a tissue-maintenance program to initiate repair after injury remains unclear. Here we examined infection by Heligmosomoides polygyrus, a co-evolved pathosymbiont of mice, to assess the epithelial response to disruption of the mucosal barrier. H. polygyrus disrupts tissue integrity by penetrating the duodenal mucosa, where it develops while surrounded by a multicellular granulomatous infiltrate2. Crypts overlying larvae-associated granulomas did not express intestinal stem cell markers, including Lgr53, in spite of continued epithelial proliferation. Granuloma-associated Lgr5- crypt epithelium activated an interferon-gamma (IFN-γ)-dependent transcriptional program, highlighted by Sca-1 expression, and IFN-γ-producing immune cells were found in granulomas. A similar epithelial response accompanied systemic activation of immune cells, intestinal irradiation, or ablation of Lgr5+ intestinal stem cells. When cultured in vitro, granuloma-associated crypt cells formed spheroids similar to those formed by fetal epithelium, and a sub-population of H. polygyrus-induced cells activated a fetal-like transcriptional program, demonstrating that adult intestinal tissues can repurpose aspects of fetal development. Therefore, re-initiation of the developmental program represents a fundamental mechanism by which the intestinal crypt can remodel itself to sustain function after injury
The financial burden of juvenile idiopathic arthritis: A Nova Scotia experience
Background: Juvenile idiopathic arthritis (JIA) is the most common childhood rheumatic illness. There is little published data on the financial burden of this illness. The primary objective of this study was to determine the annual costs borne by families of a child with JIA living in Nova Scotia (NS).Methods: All families in NS with a child followed in the Pediatric Rheumatology Clinic at the Izaak Walton Killam Health Centre (IWK) in 2009 were mailed a self-report questionnaire. The questionnaire evaluated disease related costs, gross household income and perceived financial burden. Dillman\u27s method was used to optimize return rates. Descriptive statistics were used to summarize results. Spearman\u27s correlation coefficient was used to assess the relationship of distance from the IWK and cost. The Mann-Whitney U test was used to compare median costs between groups.Results: Of 172 possible respondents, we received 54 completed questionnaires and 11 blank questionnaires (overall response rate 31.4%). Approximately one third (35.9%) of parents rated the financial burden as moderate or large and 36% rated financial resources available as poor. The median annual total cost per patient was 5535) which was a median 0.7% (range 0, 37%) of gross household incomes. The largest expense for families was visit related costs. There was not a significant relationship between total annual costs and distance from the IWK (rs = 0.18, P = 0.2). Families of a child with oligoarthritis had significantly lower costs than the families of a child with another subtype of JIA (877.00 CAD, P = 0.02).Conclusions: The costs associated with having a child with JIA in NS are on average modest, but may be considerable for some families. Oligoarticular JIA is associated with smaller costs. Many families perceive the burden to be at least moderate and the availability of financial resources to be poor. Supports should be targeted to those families most in need. © 2013 Ens et al.; licensee BioMed Central Ltd
The financial burden of juvenile idiopathic arthritis: A Nova Scotia experience
Background: Juvenile idiopathic arthritis (JIA) is the most common childhood rheumatic illness. There is little published data on the financial burden of this illness. The primary objective of this study was to determine the annual costs borne by families of a child with JIA living in Nova Scotia (NS).Methods: All families in NS with a child followed in the Pediatric Rheumatology Clinic at the Izaak Walton Killam Health Centre (IWK) in 2009 were mailed a self-report questionnaire. The questionnaire evaluated disease related costs, gross household income and perceived financial burden. Dillman\u27s method was used to optimize return rates. Descriptive statistics were used to summarize results. Spearman\u27s correlation coefficient was used to assess the relationship of distance from the IWK and cost. The Mann-Whitney U test was used to compare median costs between groups.Results: Of 172 possible respondents, we received 54 completed questionnaires and 11 blank questionnaires (overall response rate 31.4%). Approximately one third (35.9%) of parents rated the financial burden as moderate or large and 36% rated financial resources available as poor. The median annual total cost per patient was 5535) which was a median 0.7% (range 0, 37%) of gross household incomes. The largest expense for families was visit related costs. There was not a significant relationship between total annual costs and distance from the IWK (rs = 0.18, P = 0.2). Families of a child with oligoarthritis had significantly lower costs than the families of a child with another subtype of JIA (877.00 CAD, P = 0.02).Conclusions: The costs associated with having a child with JIA in NS are on average modest, but may be considerable for some families. Oligoarticular JIA is associated with smaller costs. Many families perceive the burden to be at least moderate and the availability of financial resources to be poor. Supports should be targeted to those families most in need. © 2013 Ens et al.; licensee BioMed Central Ltd
Boyajian's Star B::The co-moving stellar companion to KIC 8462852 A
The light curve of KIC 8462852, a.k.a Boyajian's Star, undergoes deep dips
the origin of which remains unclear. A faint star 2\arcsec to the east
was discovered in Keck/NIRC2 imaging in Boyajian et al. (2016), but its status
as a binary, and possible contribution to the observed variability, was
unclear. Here, we use three epochs of Keck/NIRC2 imaging, spanning five years,
in JHK near-infrared bands to obtain 1-mas precision astrometry. We show that
the two objects exhibit common proper motion, measure a relative velocity of
mas yr ( km s) and conclude
that they are a binary pair at AU projected separation. There is
marginal detection of possible orbital motion, but our astrometry is
insufficient to characterize the orbit. We show that two other point sources
are not associated with KIC 8462852. We recommend that attempts to model KIC
8462852 A's light curve should revisit the possibility that the bound stellar
companion may play a role in causing the irregular brightness variations, for
example through disruption of the orbits of bodies around the primary due to
long-term orbital evolution of the binary orbit.Comment: 11 pages, 7 figures, 2 tables Accepted for publication in Ap
The Impact of Stellar Multiplicity on Planetary Systems, I.:The Ruinous Influence of Close Binary Companions
The dynamical influence of binary companions is expected to profoundly influence planetary systems. However, the difficulty of identifying planets in binary systems has left the magnitude of this effect uncertain; despite numerous theoretical hurdles to their formation and survival, at least some binary systems clearly host planets. We present high-resolution imaging of 382 Kepler Objects of Interest (KOIs) obtained using adaptive-optics imaging and nonredundant aperture-mask interferometry on the Keck II telescope. Among the full sample of 506 candidate binary companions to KOIs, we super-resolve some binary systems to projected separations of 0.4; we instead only found 23 companions (a 4.6σ deficit), many of which must be wider pairs that are only close in projection. When the binary population is parametrized with a semimajor axis cutoff a cut and a suppression factor inside that cutoff S bin, we find with correlated uncertainties that inside au, the planet occurrence rate in binary systems is only times that of wider binaries or single stars. Our results demonstrate that a fifth of all solar-type stars in the Milky Way are disallowed from hosting planetary systems due to the influence of a binary companion
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