335 research outputs found
The 2008 Super Tuesday Tornado Outbreak: Synthetic Dual Doppler Analysis of Contrasting Tornadic Storm Types
During the Super Tuesday Tornado Outbreak on 5-6 February, a significant number of storms passed within about 40 km of WSR-88D radars. This distance, combined with the significant motion vector (from the southwest at 20-25 m per second) of relatively steady storms, is amenable to a synthetic dual Doppler analysis during the times when the storms passed the WSR-88D locations. Nine storms will be analyzed using the SDD technique. The following table provides their general characteristics and nearest approach to the 88D radars. For this data set, storm structure ranges from isolated supercell to QLCS. Each storm will be analyzed for a 40-60 min period during passage by the WSR-88D radar to determine general storm properties. Analysis of high-resolution single Doppler data around the time of passage (plus or minus 30 min), combined with 1-2 SDD analyses, will be used to examine the kinematic structure of low-level circulations (e.g., mesocyclone, downdraft) and the relation to the parent storm. This analysis may provide insights on the fundamental differences between cyclonic circulations in supercell storms and those within QCLS's
Benthic Foraminiferal response to sea level change in the mixed siliciclastic-carbonate system of southern Ashmore Trough (Gulf of Papua)
Ashmore Trough in the western Gulf of Papua (GoP) represents an outstanding modern example of a tropical mixed siliciclastic-carbonate depositional system where significant masses of both river-borne silicates and bank-derived neritic carbonates accumulate. In this study, we examine how benthic foraminiferal populations within Ashmore Trough vary in response to sea level–driven paleoenvironmental changes, particularly organic matter and sediment supply. Two 11.3-m-long piston cores and a trigger core were collected from the slope of Ashmore Trough and dated using radiocarbon and oxygen isotope measurements of planktic foraminifera. Relative abundances, principal component analyses, and cluster analyses of benthic foraminiferal assemblages in sediment samples identify three distinct assemblages whose proportions changed over time. Assemblage 1, with high abundances of Uvigerina peregrina and Bolivina robusta, dominated between ∼83 and 70 ka (early regression); assemblage 2, with high abundances of Globocassidulina subglobosa, dominated between ∼70 and 11 ka (late regression through lowstand and early transgression); and assemblage 3, with high abundances of neritic benthic species such as Planorbulina mediterranensis, dominated from ∼11 ka to the present (late transgression through early highstand). Assemblage 1 represents heightened organic carbon flux or lowered bottom water oxygen concentration, and corresponds to a time of maximum siliciclastic fluxes to the slope with falling sea level. Assemblage 2 reflects lowered organic carbon flux or elevated bottom water oxygen concentration, and corresponds to an interval of lowered siliciclastic fluxes to the slope due to sediment bypass during sea level lowstand. Assemblage 3 signals increased off-shelf delivery of neritic carbonates, likely when carbonate productivity on the outer shelf (Great Barrier Reef) increased significantly when it was reflooded. Benthic foraminiferal assemblages in the sediment sink (slopes of Ashmore Trough) likely respond to the amount and type of sediment supplied from the proximal source (outer GoP shelf)
Mechanisms of southern Caribbean SST variability over the last two millennia
We present a high-resolution Mg/Ca reconstruction of tropical Atlantic sea surface temperatures (SSTs) spanning the last 2000 years using seasonally representative foraminifera from the Cariaco Basin. The range of summer/fall SST over this interval is re
Mapping Regional Forest Evapotranspiration and Photosynthesis by Coupling Satellite Data with Ecosystem Simulation
Mapping Regional Forest Evapotranspiration and Photosynthesis by Coupling Satellite Data With Ecosystem Simulatio
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Experimental determination of the surface density for the 6He exotic nucleus
Angular distributions for the elastic scattering of 4,6He on 58Ni have been measured at near-barrier energies.
The present data, combined with others for the 4He158Ni system at intermediate energies, allowed the
determination of the 4,6He ground-state nuclear densities through an unfolding method. The experimentally
extracted nuclear densities are compared with the results of theoretical calculations
Digoxin Use and Subsequent Outcomes Among Patients in a Contemporary Atrial Fibrillation Cohort
BackgroundAlthough digoxin has long been used to treat atrial fibrillation (AF) and heart failure (HF), its safety remains controversial.ObjectivesThis study sought to describe digoxin use over time in patients with AF who were stratified by the presence or absence of HF, to characterize the predictors of digoxin use and initiation, and to correlate digoxin use with outcomes.MethodsLongitudinal patterns of digoxin use and its association with a variety of outcomes were assessed in a prospective outpatient registry conducted at 174 U.S. sites with enrollment from June 2010 to August 2011.ResultsAmong 9,619 patients with AF and serial follow-up every 6 months for up to 3 years, 2,267 (23.6%) received digoxin at study enrollment, 681 (7.1%) were initiated on digoxin during follow-up, and 6,671 (69.4%) were never prescribed digoxin. After adjusting for other medications, heart rate was 72.9 beats/min among digoxin users and 71.5 beats/min among nonusers (p < 0.0001). Prevalent digoxin use at registry enrollment was not associated with subsequent onset of symptoms, hospitalization, or mortality (in patients with HF, adjusted hazard ratio [HR] for death: 1.04; without HF, HR: 1.22). Incident digoxin use during follow-up was not associated with subsequent death in patients with HF (propensity adjusted HR: 1.05), but was associated with subsequent death in those without HF (propensity adjusted HR: 1.99).ConclusionsAfter adjustment for detailed clinical factors, digoxin use in registry patients with AF had a neutral association with outcomes under most circumstances. Because of the multiple conflicting observational reports about digoxin's safety and possible concerns in specific clinical situations, a large pragmatic trial of digoxin therapy in AF is needed
Identification of a small molecule yeast TORC1 inhibitor with a flow cytometry-based multiplex screen
TOR (target of rapamycin) is a serine/threonine kinase, evolutionarily conserved from yeast to
human, which functions as a fundamental controller of cell growth. The moderate clinical benefit
of rapamycin in mTOR-based therapy of many cancers favors the development of new TOR
inhibitors. Here we report a high throughput flow cytometry multiplexed screen using five GFPtagged
yeast clones that represent the readouts of four branches of the TORC1 signaling pathway
in budding yeast. Each GFP-tagged clone was differentially color-coded and the GFP signal of
each clone was measured simultaneously by flow cytometry, which allows rapid prioritization of
compounds that likely act through direct modulation of TORC1 or proximal signaling
components. A total of 255 compounds were confirmed in dose-response analysis to alter GFP
expression in one or more clones. To validate the concept of the high throughput screen, we have
characterized CID 3528206, a small molecule most likely to act on TORC1 as it alters GFP
expression in all five GFP clones in an analogous manner to rapamycin. We have shown that CID
3528206 inhibited yeast cell growth, and that CID 3528206 inhibited TORC1 activity both in vitro
and in vivo with EC50s of 150 nM and 3.9 μM, respectively. The results of microarray analysis
and yeast GFP collection screen further support the notion that CID 3528206 and rapamycin
modulate similar cellular pathways. Together, these results indicate that the HTS has identified a
potentially useful small molecule for further development of TOR inhibitors
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