We report on the measurement of the γp→J/ψp cross section from E_{γ}=11.8 GeV down to the threshold at 8.2 GeV using a tagged photon beam with the GlueX experiment. We find that the total cross ...section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section dσ/dt has an exponential slope of 1.67±0.39 GeV^{-2} at 10.7 GeV average energy. The LHCb pentaquark candidates P_{c}^{+} can be produced in the s channel of this reaction. We see no evidence for them and set model-dependent upper limits on their branching fractions B(P_{c}^{+}→J/ψp) and cross sections σ(γp→P_{c}^{+})×B(P_{c}^{+}→J/ψp).
Accelerating incoherent dedispersion Barsdell, B. R; Bailes, M; Barnes, D. G ...
Monthly notices of the Royal Astronomical Society,
20/May , Letnik:
422, Številka:
1
Journal Article
Recenzirano
Incoherent dedispersion is a computationally intensive problem that appears frequently in pulsar and transient astronomy. For current and future transient pipelines, dedispersion can dominate the ...total execution time, meaning its computational speed acts as a constraint on the quality and quantity of science results. It is thus critical that the algorithm be able to take advantage of trends in commodity computing hardware. With this goal in mind, we present an analysis of the 'direct', 'tree' and 'sub-band' dedispersion algorithms with respect to their potential for efficient execution on modern graphics processing units (GPUs). We find all three to be excellent candidates, and proceed to describe implementations in c for cuda using insight gained from the analysis. Using recent CPU and GPU hardware, the transition to the GPU provides a speed-up of nine times for the direct algorithm when compared to an optimized quad-core CPU code. For realistic recent survey parameters, these speeds are high enough that further optimization is unnecessary to achieve real-time processing. Where further speed-ups are desirable, we find that the tree and sub-band algorithms are able to provide three to seven times better performance at the cost of certain smearing, memory consumption and development time trade-offs. We finish with a discussion of the implications of these results for future transient surveys. Our GPU dedispersion code is publicly available as a c library at http://dedisp.googlecode.com/.
National Trends in Ambulatory Oral Anticoagulant Use Barnes, Geoffrey D., MD, MSc; Lucas, Eleanor, BA; Alexander, G. Caleb, MD, MS ...
The American journal of medicine,
12/2015, Letnik:
128, Številka:
12
Journal Article
Recenzirano
Odprti dostop
Abstract Background Four direct oral anticoagulants (DOACs) have been brought to market for the treatment of nonvalvular atrial fibrillation and venous thromboembolism. Many forces, including ...numerous positive trial results, emerging safety concerns, marketing, and promotion, may shape DOAC adoption by providers. However, relatively little is known regarding their ambulatory utilization compared with warfarin, as well as the degree to which they have decreased under-treatment of atrial fibrillation. Methods We used the IMS Health National Disease and Therapeutic Index, a nationally representative audit of outpatient office visits, to estimate the use of warfarin and DOACs between 2009 and 2014. Results Overall, visits with anticoagulation use increased from 2.05 (95% confidence interval CI, 1.82-2.27) to 2.83 (95% CI, 2.49-3.17) million (M) quarterly visits ( P < .001). Of these, DOAC use has grown to 4.21M (95% CI, 3.63M-4.79M; 38.2% of total) treatment visits in 2014 since their introduction in 2010. Use of all oral anticoagulants in treatment visits for atrial fibrillation has increased from 0.88M (95% CI, 0.74M-1.02M) to 1.72M (95% CI, 1.47M-1.97M; P < .001), with similar DOAC and warfarin use in 2014. Atrial fibrillation visits with anticoagulant use increased from 51.9% (95% CI, 50.4%-53.8%) to 66.9% (95% CI, 65.0%-69.3%) between 2009 and 2014 ( P < .001). In 2014, rivaroxaban was the most commonly prescribed DOAC for atrial fibrillation (47.9% of office visits), followed by apixaban (26.5%) and dabigatran (25.5%). Conclusions Direct oral anticoagulants have been adopted rapidly, matching the use of warfarin, and are associated with increased use of oral anticoagulation for patients with atrial fibrillation.
It is not clear how often patients receive aspirin (acetylsalicylic acid) while receiving oral anticoagulation with warfarin sodium without a clear therapeutic indication for aspirin, such as a ...mechanical heart valve replacement, recent percutaneous coronary intervention, or acute coronary syndrome. The clinical outcomes of such patients treated with warfarin and aspirin therapy compared with warfarin monotherapy are not well defined to date.
To evaluate the frequency and outcomes of adding aspirin to warfarin for patients without a clear therapeutic indication for combination therapy.
A registry-based cohort study of adults enrolled at 6 anticoagulation clinics in Michigan (January 1, 2010, to December 31, 2017) who were receiving warfarin therapy for atrial fibrillation or venous thromboembolism without documentation of a recent myocardial infarction or history of valve replacement.
Aspirin use without therapeutic indication.
Rates of any bleeding, major bleeding events, emergency department visits, hospitalizations, and thrombotic events at 1, 2, and 3 years.
Of the study cohort of 6539 patients (3326 men 50.9%; mean SD age, 66.1 15.5 years), 2453 patients (37.5%) without a clear therapeutic indication for aspirin were receiving combination warfarin and aspirin therapy. Data from 2 propensity score-matched cohorts of 1844 patients were analyzed (warfarin and aspirin vs warfarin only). At 1 year, patients receiving combination warfarin and aspirin compared with those receiving warfarin only had higher rates of overall bleeding (cumulative incidence, 26.0%; 95% CI, 23.8%-28.3% vs 20.3%; 95% CI, 18.3%-22.3%; P < .001), major bleeding (5.7%; 95% CI, 4.6%-7.1% vs 3.3%; 95% CI, 2.4%-4.3%; P < .001), emergency department visits for bleeding (13.3%; 95% CI, 11.6%-15.1% vs 9.8%; 95% CI, 8.4%-11.4%; P = .001), and hospitalizations for bleeding (8.1%; 6.8%-9.6% vs 5.2%; 4.1%-6.4%; P = .001). Rates of thrombosis were similar, with a 1-year cumulative incidence of 2.3% (95% CI, 1.6%-3.1%) for those receiving combination warfarin and aspirin therapy compared with 2.7% (95% CI, 2.0%-3.6%) for those receiving warfarin alone (P = .40). Similar findings persisted during 3 years of follow-up as well as in sensitivity analyses.
Compared with warfarin monotherapy, receipt of combination warfarin and aspirin therapy was associated with increased bleeding and similar observed rates of thrombosis. Further research is needed to better stratify which patients may benefit from aspirin while anticoagulated with warfarin for atrial fibrillation or venous thromboembolism; clinicians should be judicious in selecting patients for combination therapy.
It is widely believed that the brain processes information and stores memories by modifying and stabilizing synaptic connections between neurons. In experimental models of synaptic plasticity, such ...as long-term potentiation (LTP), the stabilization of changes in synaptic strength requires rapid de novo RNA and protein synthesis. Candidate genes, which could underlie activity-dependent plasticity, have been identified on the basis of their rapid induction in brain neurons. Immediate-early genes (IEGs) are induced in hippocampal neurons by high-frequency electrical stimulation that induces LTP and by behavioral training that results in long-term memory (LTM) formation. Here, we investigated the role of the IEG Arc (also termed Arg3.1) in hippocampal plasticity. Arc protein is known to be enriched in dendrites of hippocampal neurons where it associates with cytoskeletal proteins (Lyford et al., 1995). Arc is also notable in that its mRNA and protein accumulate in dendrites at sites of recent synaptic activity (Steward et al., 1998). We used intrahippocampal infusions of antisense oligodeoxynucleotides to inhibit Arc protein expression and examined the effect of this treatment on both LTP and spatial learning. Our studies show that disruption of Arc protein expression impairs the maintenance phase of LTP without affecting its induction and impairs consolidation of LTM for spatial water task training without affecting task acquisition or short-term memory. Thus, Arc appears to play a fundamental role in the stabilization of activity-dependent hippocampal plasticity.
Early career researchers and clinicians face unique challenges in comparison with more senior colleagues, for instance connecting with expert leaders outside of their own institution to enhance their ...expertise. As the largest international thrombosis and hemostasis professional society, the ISTH can play a central role in supporting the development of early career professionals. The ISTH Early Career Task Force was formed to improve support for, and encourage collaboration between early career thrombosis and hemostasis researchers and clinicians. These activities include (1) maintaining an online forum for early career ISTH members to connect, promote clinical, research, funding and educational activities, and to generate a sense of community; (2) broaden ISTH's reach with early career professionals in the developing world through promotion of the Reach-the-World fellowships and translating ISTH websites into six languages; (3) encourage early career engagement with ISTH activities, such as guidelines and guidance document processing and online webinar series; and (4) establishing this early career forum series in this journal. The JTH Forum series will highlight the early career perspective on a wide range of issues relevant to this group, and all ISTH early career members are encouraged to contribute.
Abstract Extracellular matrix (ECM) scaffolds prepared from different tissue sources or using different methods have been demonstrated to have distinctive effects upon cell adhesion patterns and the ...ability to support and maintain differentiated phenotypes. It is unknown whether the molecular composition or the ultrastructure of the ECM plays a greater role in determining the phenotype of the cells with which it comes into contact. However, when implanted, the topology and ligand landscape of the material will determine the host molecules that bind and the type and behavior of cells that mediate the host response. Therefore, a comprehensive understanding of surface characteristics is essential in the design of scaffolds for specific clinical applications. The surface characteristics of ECM scaffolds derived from porcine urinary bladder, small intestine, and liver as well as the effects of two commonly used methods of chemical cross-linking upon UBM were investigated. Electron microscopy and time of flight secondary ion mass spectroscopy were used to examine the surface characteristics of the scaffolds. The results show that ECM scaffolds have unique morphologic and structural properties which are dependant on the organ or tissue from which the scaffold is harvested. Furthermore, the results show that the surface characteristics of an ECM scaffold are changed through chemical cross-linking.
The heavy ion component of the low‐energy (eV to hundreds of eV) ion population in the inner magnetosphere, also known as the O+ torus, is a crucial population for various aspects of magnetospheric ...dynamics. Yet even though its existence has been known since the 1980s, its formation remains an open question. We present a comprehensive study of a low‐energy (<keV), bidirectional O+ outflow event, which occurred deep into the inner magnetosphere (inside L = 4), and was observed by the Helium, Oxygen, Proton and Electron (HOPE) instrument aboard the Van Allen Probe B. The observed spectrogram exhibited multiple bands of field‐aligned intensity enhancements with energy dispersion. A 2‐D guiding‐center test‐particle tracing simulation demonstrates that the observed spectral features can be attributed to O+ ions exiting both hemispheres of the nightside ionosphere over L ~ 3–4 latitudinal and magnetic local time (MLT) ~ 21 to 23 hr longitudinal extent, directly entering the inner magnetosphere, and subsequently bouncing from one hemisphere to the other. The outflow is associated with earthward field‐aligned Poynting flux enhancement and field‐aligned electron beams, as observed at the Van Allen Probes location, as well as with strong upward field‐aligned current, as revealed by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) at the ionospheric footpoint of the spacecraft. O+ partial density in the region outside plasmapause was significantly enhanced by the outflow population, exceeding the H+ density and indicating the possible formation of an O+ torus.
Key Points
We observe low‐energy (<keV) O+ outflow well inside geosynchronous orbit during a geomagnetic storm
We conclude that the outflow has a short time duration but extends in L ~ 3–4 and MLT ~ 21–23 hr
The O+ partial number density enhances significantly due to the outflow population and exceeds that of H+
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