368 research outputs found
Man, Meaning, Ministry: The Quest of the Historical Vanstone
This article reflects on the contemporary relevance of the writing s of the Anglican clergyman W. H. Vanstone (1923-1999) by looking at his three highly influential books in the context of their author’s life and work. This biographical study takes in much fresh material gathered from anecdotal and personal information from friends and colleagues as well as study of Vanstone’s unpublished writings. The article concludes with reflections on the theological significance of Vanstone’s writings and the lessons that can be drawn from them and from their author’s remarkable life and ministry
A Simplified Model for Distortional Buckling of Channels and Zees in Flexure
Certain cold-formed sections like channels and zees, when subjected to bending in the plane of the web, often fail in laboratory tests at a load less than that predicted by standard specification equations. The mode of failure is an upward movement of the compression flange and lip relative to the web, which may remain fairly plane. When bends which were right angles change dramatically under load, the section changes shape, or distorts, resulting in a reduction of the section stiffness followed by buckling of the flange. Such a failure is referred to as distortional buckling . An analytical solution to the distortional buckling problem has been proposed by Hancock of the University of Sydney. This method was used to calculate distortional buckling capacities of around 200 shapes and a curve was fit to the results. Finally, a simplified expression was developed to check this limit state with minimal effort. Several full-scale tests were performed on channels and zees of various thicknesses and bracing conditions to verify the Hancock method
Star Formation in the Milky Way and Nearby Galaxies
We review progress over the past decade in observations of large-scale star
formation, with a focus on the interface between extragalactic and Galactic
studies. Methods of measuring gas contents and star formation rates are
discussed, and updated prescriptions for calculating star formation rates are
provided. We review relations between star formation and gas on scales ranging
from entire galaxies to individual molecular clouds.Comment: 55 pages, 15 figures, in press for Annual Reviews of Astronomy and
Astrophysics; Updated with corrected equation 5, improved references, and
other minor change
The Origin and Kinematics of Cold Gas in Galactic Winds: Insight from Numerical Simulations
We study the origin of Na I absorbing gas in ultraluminous infrared galaxies
motivated by the recent observations by Martin of extremely superthermal
linewidths in this cool gas. We model the effects of repeated supernova
explosions driving supershells in the central regions of molecular disks with
M_d=10^10 M_\sun, using cylindrically symmetric gas dynamical simulations run
with ZEUS-3D. The shocked swept-up shells quickly cool and fragment by
Rayleigh-Taylor instability as they accelerate out of the dense, stratified
disks. The numerical resolution of the cooling and compression at the shock
fronts determines the peak shell density, and so the speed of Rayleigh-Taylor
fragmentation. We identify cooled shells and shell fragments as Na I absorbing
gas and study its kinematics. We find that simulations with a numerical
resolution of \le 0.2 pc produce multiple Rayleigh-Taylor fragmented shells in
a given line of sight. We suggest that the observed wide Na I absorption lines,
= 320 \pm 120 km s^-1 are produced by these multiple fragmented shells
traveling at different velocities. We also suggest that some shell fragments
can be accelerated above the observed average terminal velocity of 750 km s^-1
by the same energy-driven wind with an instantaneous starburst of \sim 10^9
M_\sun. The bulk of mass is traveling with the observed average shell velocity
330 \pm 100 km s^-1. Our results show that an energy-driven bubble causing
Rayleigh-Taylor instabilities can explain the kinematics of cool gas seen in
the Na I observations without invoking additional physics relying primarily on
momentum conservation, such as entrainment of gas by Kelvin-Helmholtz
instabilities, ram pressure driving of cold clouds by a hot wind, or radiation
pressure acting on dust. (abridged)Comment: 65 pages, 22 figures, accepted by Astrophys. J. Changes during
refereeing focused on context and comparison to observation
Geographic and ecological eimensions of host plant-associated genetic differentiation and speciation in the Rhagoletis cingulata (Diptera: Tephritidae) sibling species group
Ascertaining the causes of adaptive radiation is central to understanding how new species arise and come to vary with their resources. The ecological theory posits adaptive radiation via divergent natural selection associated with novel resource use; an alternative suggests character displacement following speciation in allopatry and then secondary contact of reproductively isolated but ecologically similar species. Discriminating between hypotheses, therefore, requires the establishment of a key role for ecological diversification in initiating speciation versus a secondary role in facilitating co-existence. Here, we characterize patterns of genetic variation and postzygotic reproductive isolation for tephritid fruit flies in the Rhagoletis cingulata sibling species group to assess the significance of ecology, geography, and non-adaptive processes for their divergence. Our results support the ecological theory: no evidence for intrinsic postzygotic reproductive isolation was found between two populations of allopatric species, while nuclear-encoded microsatellites implied strong ecologically based reproductive isolation among sympatric species infesting different host plants. Analysis of mitochondrial DNA suggested, however, that cytoplasmic-related reproductive isolation may also exist between two geographically isolated populations within R cingulata. Thus, ecology associated with sympatric host shifts and cytoplasmic effects possiblyFil: Doellman, Meredith M.. University of Notre Dame-Indiana; Estados UnidosFil: Schuler, Hannes. University Of Bozen-bolzano; ItaliaFil: Saint Jean, Gilbert. University of Notre Dame-Indiana; Estados UnidosFil: Hood, Glenn R.. Wane State University; Estados UnidosFil: Egan, Scott P.. Rice University; Estados UnidosFil: Powell, Thomas H. Q.. University of Binghamton; Estados UnidosFil: Glover, Mary M.. University of Notre Dame-Indiana; Estados UnidosFil: Bruzzese, Daniel J.. University of Notre Dame-Indiana; Estados UnidosFil: Smith, James J.. Michigan State University; Estados UnidosFil: Yee, Wee L.. United States Department of Agriculture. Agricultural Research Service; ArgentinaFil: Goughnour, Robert B.. Washington State University; Estados UnidosFil: Rull Gabayet, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Aluja, Martín. Instituto de Ecología A.c.; MéxicoFil: Feder, Jeffrey L.. University of Notre Dame-Indiana; Estados Unido
Early Identification and Prevention of the Spread of Ebola - United States
In response to the 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa, CDC prepared for the potential introduction of Ebola into the United States. The immediate goals were to rapidly identify and isolate any cases of Ebola, prevent transmission, and promote timely treatment of affected patients. CDC\u27s technical expertise and the collaboration of multiple partners in state, local, and municipal public health departments; health care facilities; emergency medical services; and U.S. government agencies were essential to the domestic preparedness and response to the Ebola epidemic and relied on longstanding partnerships. CDC established a comprehensive response that included two new strategies: 1) active monitoring of travelers arriving from countries affected by Ebola and other persons at risk for Ebola and 2) a tiered system of hospital facility preparedness that enabled prioritization of training. CDC rapidly deployed a diagnostic assay for Ebola virus (EBOV) to public health laboratories. Guidance was developed to assist in evaluation of patients possibly infected with EBOV, for appropriate infection control, to support emergency responders, and for handling of infectious waste. CDC rapid response teams were formed to provide assistance within 24 hours to a health care facility managing a patient with Ebola. As a result of the collaborations to rapidly identify, isolate, and manage Ebola patients and the extensive preparations to prevent spread of EBOV, the United States is now better prepared to address the next global infectious disease threat.The activities summarized in this report would not have been possible without collaboration with many U.S. and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html)
Role of procoagulant microparticles in mediating complications and outcome of acute liver injury/acute liver failure
Microparticles (MPs), membrane fragments of 0.1–1.0 μm, are derived from many cell types in response to systemic inflammation. Acute liver failure (ALF) is a prototypical syndrome of systemic inflammatory response syndrome (SIRS) associated with a procoagulant state. We hypothesized that patients with ALF develop increased procoagulant MPs in proportion to the severity of systemic complications and adverse outcome. Fifty patients with acute liver injury (ALI), 78% of whom also had hepatic encephalopathy (HE; ALF), were followed until day 21 after admission. MPs were characterized by Invitrox Sizing, Antigen Detection and Enumeration, a light-scattering technology that can enumerate MPs as small as 0.15 μm, and by flow cytometry. Procoagulant activity was assessed by a functional MP-tissue factor (MP-TF) assay. Sixteen patients (32%) died and 27 (54%) recovered without liver transplantation (LT). Total MPs (0.15–1.0 μm) were present in nearly 19-fold higher concentrations in ALI/ALF patients, compared to healthy controls (P < 0.0001). MP-TF assays revealed high procoagulant activity (9.05 ± 8.82 versus 0.24 ± 0.14 pg/mL in controls; P = 0.0008). MP concentrations (0.28–0.64 μm) were higher in patients with the SIRS and high-grade HE, and MPs in the 0.36–0.64-μm size range increased in direct proportion to SIRS severity (P < 0.001) and grade of HE (P < 0.002). Day 1 MPs (0.28–0.64 μm) correlated with laboratory predictors of death/LT (higher phosphate and creatinine; lower bicarbonate), and day 1 and 3 MPs were higher in patients who died or underwent LT, compared to spontaneous survivors (P ≤ 0.01). By flow cytometry, 87% of patients had circulating CD41+ MPs, indicating platelet origin. Conclusion: Highly procoagulant MPs of specific size ranges are associated with the SIRS, systemic complications, and adverse outcome of ALI/ALF. MPs may contribute to the multiorgan system failure and high mortality of ALF
Wireless Communication Networks for Gas Turbine Engine Testing
A new trend in the field of Aeronautical Engine Health Monitoring is the implementation of wireless sensor networks (WSNs) for data acquisition and condition monitoring to partially replace heavy and complex wiring harnesses, which limit the versatility of the monitoring process as well as creating practical deployment issues. Using wireless technologies instead of fixed wiring will fuel opportunities for reduced cabling, faster sensor and network deployment, increased data acquisition flexibility and reduced cable maintenance costs. However, embedding wireless technology into an aero engine (even in the ground testing application considered here) presents some very significant challenges, e.g. a harsh environment with a complex RF transmission environment, high sensor density and high data-rate. In this paper we discuss the results of the Wireless Data Acquisition in Gas Turbine Engine Testing (WIDAGATE) project, which aimed to design and simulate such a network to estimate network performance and de-risk the wireless techniques before the deployment
Composite genome map and recombination parameters derived from three archetypal lineages of Toxoplasma gondii
Toxoplasma gondii is a highly successful protozoan parasite in the phylum Apicomplexa, which contains numerous animal and human pathogens. T.gondii is amenable to cellular, biochemical, molecular and genetic studies, making it a model for the biology of this important group of parasites. To facilitate forward genetic analysis, we have developed a high-resolution genetic linkage map for T.gondii. The genetic map was used to assemble the scaffolds from a 10X shotgun whole genome sequence, thus defining 14 chromosomes with markers spaced at ∼300 kb intervals across the genome. Fourteen chromosomes were identified comprising a total genetic size of ∼592 cM and an average map unit of ∼104 kb/cM. Analysis of the genetic parameters in T.gondii revealed a high frequency of closely adjacent, apparent double crossover events that may represent gene conversions. In addition, we detected large regions of genetic homogeneity among the archetypal clonal lineages, reflecting the relatively few genetic outbreeding events that have occurred since their recent origin. Despite these unusual features, linkage analysis proved to be effective in mapping the loci determining several drug resistances. The resulting genome map provides a framework for analysis of complex traits such as virulence and transmission, and for comparative population genetic studies
A humanized monoclonal antibody against the endothelial chemokine CCL21 for the diagnosis and treatment of inflammatory bowel disease
Chemokines are small proteins that promote leukocyte migration during development, infection, and inflammation. We and others isolated the unique chemokine CCL21, a potent chemo-attractant for naïve T-cells, naïve B-cells, and immature dendritic cells. CCL21 has a 37 amino acid carboxy terminal extension that is distinct from the rest of the chemokine family, which is thought to anchor it to venule endothelium where the amino terminus can interact with its cognate receptor, CCR7. We and others have reported that venule endothelium expressing CCL21 plays a crucial role in attracting naïve immune cells to sites of antigen presentation. In this study we generated a series of monoclonal antibodies to the amino terminus of CCL21 in an attempt to generate an antibody that blocked the interaction of CCL21 with its receptor CCR7. We found one humanized clone that blocked naïve T-cell migration towards CCL21, while memory effector T-cells were less affected. Using this monoclonal antibody, we also demonstrated that CCL21 is expressed in the mucosal venule endothelium of the large majority of inflammatory bowel diseases (IBD), including Crohn's disease, ulcerative colitis, and also in celiac disease. This expression correlated with active IBD in 5 of 6 cases, whereas none of 6 normal bowel biopsies had CCL21 expression. This study raises the possibility that this monoclonal antibody could be used to diagnose initial or recurrent of IBD. Significantly, this antibody could also be used for therapeutic intervention in IBD by selectively interfering with recruitment of naïve immune effector cells to sites of antigen presentation, without harming overall memory immunity
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