1,376 research outputs found
Completed cohomology of Shimura curves and a p-adic Jacquet-Langlands correspondence
We study indefinite quaternion algebras over totally real fields F, and give
an example of a cohomological construction of p-adic Jacquet-Langlands
functoriality using completed cohomology. We also study the (tame) levels of
p-adic automorphic forms on these quaternion algebras and give an analogue of
Mazur's `level lowering' principle.Comment: Updated version. Contains some minor corrections compared to the
published versio
Performance Measures Using Electronic Health Records: Five Case Studies
Presents the experiences of five provider organizations in developing, testing, and implementing four types of electronic quality-of-care indicators based on EHR data. Discusses challenges, and compares results with those from traditional indicators
What really matters about teacher education at Cathedrals Group Universities: volume 2 the case studies
The case studies show insight into the extent that there is a shared understanding between schools, students and staff members in some of England’s oldest providers of teacher education in England. Is there something particular about that provision? Could it be described as distinctively, implicitly or explicitly Christian? Is there a sense of shared thinking about the answers to these questions in the provision of teacher education and the students, university tutors and school staff members who partner with these universities to educate the next generation of teachers?
This document provides five answers to those questions. The answers are snapshots of the perception of teacher education at these universities, at a time when teacher education has become a major purpose of schools, and universities have found themselves being questioned and challenged about their role in the development of new teachers
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Complex dynamical networks constructed with fully controllable nonlinear nanomechanical oscillators
Control of the global parameters of complex networks has been explored experimentally in a variety of contexts. Yet, the more difficult prospect of realizing arbitrary network architectures, especially analog physical networks that provide dynamical control of individual nodes and edges, has remained elusive. Given the vast hierarchy of time scales involved, it also proves challenging to measure a complex network’s full internal dynamics. These span from the fastest nodal dynamics to very slow epochs over which emergent global phenomena, including network synchronization and the manifestation of exotic steady states, eventually emerge. Here, we demonstrate an experimental system that satisfies these requirements. It is based upon modular, fully controllable, nonlinear radio frequency nanomechanical oscillators, designed to form the nodes of complex dynamical networks with edges of arbitrary topology. The dynamics of these oscillators and their surrounding network are analog and continuous-valued and can be fully interrogated in real time. They comprise a piezoelectric nanomechanical membrane resonator, which serves as the frequency-determining element within an electrical feedback circuit. This embodiment permits network interconnections entirely within the electrical domain and provides unprecedented node and edge control over a vast region of parameter space. Continuous measurement of the instantaneous amplitudes and phases of every constituent oscillator node are enabled, yielding full and detailed network data without reliance upon statistical quantities. We demonstrate the operation of this platform through the real-time capture of the dynamics of a three-node ring network as it evolves from the uncoupled state to full synchronization
Probing Unexpected Reactivity in Radiometal Chemistry: Indium-111-Mediated Hydrolysis of Hybrid Cyclen-Hydroxypyridinone Ligands
Chelators based on hydroxypyridinones have utility in
incorporating
radioactive metal ions into diagnostic and therapeutic agents used
in nuclear medicine. Over the course of our hydroxypyridinone studies,
we have prepared two novel chelators, consisting of a cyclen (1,4,7,10-tetraazacyclododecane)
ring bearing two pendant hydroxypyridinone groups, appended via methylene
acetamide motifs at either the 1,4-positions (L1) or 1,7-positions (L2) of the cyclen ring. In radiolabeling reactions of L1 or L2 with the γ-emitting radioisotope, [111In]In3+, we have observed radiometal-mediated hydrolysis of a single
amide group of either L1 or L2. The reaction of either [111In]In3+ or [natIn]In3+ with either L1 or L2, in aqueous alkaline solutions at 80 °C, initially results
in formation of [In(L1)]+ or [In(L2)]+, respectively. Over time, each of these species undergoes In3+-mediated hydrolysis of a single amide group to yield species
in which In3+ remains coordinated to the resultant chelator,
which consists of a cyclen ring bearing a single hydroxypyridinone
group and a single carboxylate group. The reactivity toward hydrolysis
is higher for the L1 complex
compared to that for the L2 complex.
Density functional theory calculations corroborate these experimental
findings and importantly indicate that the activation energy required
for the hydrolysis of L1 is significantly
lower than that required for L2. This is the first reported example of a chelator undergoing radiometal-mediated
hydrolysis to form a radiometalated complex. It is possible that metal-mediated
amide bond cleavage is a source of instability in other radiotracers,
particularly those in which radiometal complexation occurs in aqueous,
basic solutions at high temperatures. This study highlights the importance
of appropriate characterization of radiolabeled products
Supernova Simulations and Strategies For the Dark Energy Survey
We present an analysis of supernova light curves simulated for the upcoming
Dark Energy Survey (DES) supernova search. The simulations employ a code suite
that generates and fits realistic light curves in order to obtain distance
modulus/redshift pairs that are passed to a cosmology fitter. We investigated
several different survey strategies including field selection, supernova
selection biases, and photometric redshift measurements. Using the results of
this study, we chose a 30 square degree search area in the griz filter set. We
forecast 1) that this survey will provide a homogeneous sample of up to 4000
Type Ia supernovae in the redshift range 0.05<z<1.2, and 2) that the increased
red efficiency of the DES camera will significantly improve high-redshift color
measurements. The redshift of each supernova with an identified host galaxy
will be obtained from spectroscopic observations of the host. A supernova
spectrum will be obtained for a subset of the sample, which will be utilized
for control studies. In addition, we have investigated the use of combined
photometric redshifts taking into account data from both the host and
supernova. We have investigated and estimated the likely contamination from
core-collapse supernovae based on photometric identification, and have found
that a Type Ia supernova sample purity of up to 98% is obtainable given
specific assumptions. Furthermore, we present systematic uncertainties due to
sample purity, photometric calibration, dust extinction priors, filter-centroid
shifts, and inter-calibration. We conclude by estimating the uncertainty on the
cosmological parameters that will be measured from the DES supernova data.Comment: 46 pages, 30 figures, resubmitted to ApJ as Revision 2 (final author
revision), which has subtle editorial differences compared to the published
paper (ApJ, 753, 152). Note that this posting includes PDF only due to a bug
in either the latex macros or the arXiv submission system. The source files
are available in the DES document database:
http://des-docdb.fnal.gov/cgi-bin/ShowDocument?docid=624
Avian Binocularity and Adaptation to Nocturnal Environments: Genomic Insights froma Highly Derived Visual Phenotype
Typical avian eyes are phenotypically engineered for photopic vision (daylight). In contrast, the highly derived eyes of the barn owl (Tyto alba) are adapted for scotopic vision (dim light). The dramatic modifications distinguishing barn owl eyes from other birds include: 1) shifts in frontal orientation to improve binocularity, 2) rod-dominated retina, and 3) enlarged corneas and lenses. Some of these features parallel mammalian eye patterns, which are hypothesized to have initially evolved in nocturnal environments. Here, we used an integrative approach combining phylogenomics and functional phenotypes of 211 eye-development genes across 48 avian genomes representing most avian orders, including the stem lineage of the scotopic-adapted barn owl. Overall, we identified 25 eye-development genes that coevolved under intensified or relaxed selection in the retina, lens, cornea, and optic nerves of the barn owl. The agtpbp1 gene, which is associated with the survival of photoreceptor populations, was pseudogenized in the barn owl genome. Our results further revealed that barn owl retinal genes responsible for the maintenance, proliferation, and differentiation of photoreceptors experienced an evolutionary relaxation. Signatures of relaxed selection were also observed in the lens and cornea morphology-associated genes, suggesting that adaptive evolution in these structures was essentially structural. Four eye-development genes (ephb1, phactr4, prph2, and rs1) evolved in positive association with the orbit convergence in birds and under relaxed selection in the barn owl lineage, likely contributing to an increased reliance on binocular vision in the barn owl. Moreover, we found evidence of coevolutionary interactions among genes that are expressed in the retina, lens, and optic nerve, suggesting synergetic adaptive events. Our study disentangles the genomic changes governing the binocularity and low-light perception adaptations of barn owls to nocturnal environments while revealing the molecular mechanisms contributing to the shift from the typical avian photopic vision to the more-novel scotopic-adapted eye
Sulfur dioxide and particles in quiescent volcanic plumes from Poás, Arenal, and Colima Volcanos, Costa Rica and Mexico
Measurements of SO2 emission rates and concentrations and of particle distribution, size, shape, and composition were made in quiescent volcanic plumes emitted into the troposphere from Poás and Arenal volcanos, Costa Rica, and Colima volcano, Mexico. SO2 emission rates were 700±180 metric tons per day (t/d) for Poás, 210±30 t/d for Arenal, and 320±50 t/d for Colima. The concentrations of SO2 calculated from the COSPEC/lidar data were 5–380 ppb. Concentrations of SO2measured directly by flame photometry were 10–250 ppb. Particles collected in the plumes with a quartz crystal microbalance impactor were mostly less than 3 μm in diameter and consisted of droplets of dilute sulfur-bearing solutions and minor amounts of larger silicate particles coated with a sulfur-bearing film or crust. Total particle concentrations were 4.7 μg/m3 for Poás and 18.8 μg/m3for Colima. Comparison of concentrations of SO2 in the plumes with gas samples collected at fumaroles on the ground suggests that the plumes are diluted by the atmosphere by factors of up to 105
The Kinetics of Specific Immune Responses in Rhesus Monkeys Inoculated with Live Recombinant BCG Expressing SIV Gag, Pol, Env, and Nef Proteins
AbstractDevelopment of an effective preventive or therapeutic vaccine against HIV-1 is an important goal in the fight against AIDS. Effective virus clearance and inhibition of spread to target organs depends principally on the cellular immune response. Therefore, a vaccine against HIV-1 should elicit virus-specific cytotoxic lymphocyte (CTL) responses to eliminate the virus during the cell-associated stages of its life cycle. The vaccine should also be capable of inducing immunity at the mucosal surfaces, the primary route of transmission. Recombinant Bacille Calmette–Guérin (BCG) expressing viral proteins offers an excellent candidate vaccine in view of its safety and ability to persist intracellularly, resulting in the induction of long-lasting immunity and stimulation of the cellular immune response. BCG can be administered orally to induce HIV-specific immunity at the mucosal surfaces. The immunogenicity of four recombinant BCG constructs expressing simian immunodeficiency virus (SIV) Gag, Pol, Env, and Nef proteins was tested in rhesus macaques. A single simultaneous inoculation of all four recombinants elicited SIV-specific IgA and IgG antibody, and cellular immune responses, including CTL and helper T cell proliferation. Our results demonstrate that BCG recombinant vectors can induce concomitant humoral and cellular immune responses to the major proteins of SIV
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