10,104 research outputs found
Search for b→u transitions in B±→[K∓π±π0]DK± decays
We present a study of the decays B±→DK± with D mesons reconstructed in the K+π-π0 or K-π+π0 final states, where D indicates a D0 or a D̅ 0 meson. Using a sample of 474×106 BB̅ pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we measure the ratios R±≡Γ(B±→[K∓π±π0]DK±)/Γ(B±→[K±π∓π0]DK±). We obtain R+=(5-10+12(stat)-4+2(syst))×10-3 and R-=(12-10+12(stat)-5+3(syst))×10-3, from which we extract the upper limits at 90% probability: R+<23×10-3 and R-<29×10-3. Using these measurements, we obtain an upper limit for the ratio rB of the magnitudes of the b→u and b→c amplitudes rB<0.13 at 90% probability
A review of interactive narrative systems and technologies: a training perspective
As an emerging form of digital entertainment, interactive narrative has attracted great attention of researchers over the past decade. Recently, there is an emerging trend to apply interactive narrative for training and simulation. An interactive narrative system allows players to proactively interact with simulated entities in a virtual world and have the ability to alter the progression of a storyline. In simulation-based training, the use of an interactive narrative system enables the possibility to offer engaging, diverse and personalized narratives or scenarios for different training purposes. This paper provides a review of interactive narrative systems and technologies from a training perspective. Specifically, we first propose a set of key requirements in developing interactive narrative systems for simulation-based training. Then we review nine representative existing systems with respect to their system architectures, features and related mechanisms. To examine their applicability to training, we investigate and compare the reviewed systems based on the functionalities and modules that support the proposed requirements. Furthermore, we discuss some open research issues on future development of interactive narrative technologies for training applications
Prospects for high-resolution microwave spectroscopy of methanol in a Stark-deflected molecular beam
Recently, the extremely sensitive torsion-rotation transitions in methanol
have been used to set a tight constraint on a possible variation of the
proton-to-electron mass ratio over cosmological time scales. In order to
improve this constraint, laboratory data of increased accuracy will be
required. Here, we explore the possibility for performing high-resolution
spectroscopy on methanol in a Stark-deflected molecular beam. We have
calculated the Stark shift of the lower rotational levels in the ground
torsion-vibrational state of CH3OH and CD3OH molecules, and have used this to
simulate trajectories through a typical molecular beam resonance setup.
Furthermore, we have determined the efficiency of non-resonant multi-photon
ionization of methanol molecules using a femtosecond laser pulse. The described
setup is in principle suited to measure microwave transitions in CH3OH at an
accuracy below 10^{-8}
Towards a data-driven approach to scenario generation for serious games
Serious games have recently shown great potential to be adopted in many applications, such as training and education. However, one critical challenge in developing serious games is the authoring of a large set of scenarios for different training objectives. In this paper, we propose a data-driven approach to automatically generate scenarios for serious games. Compared with other scenario generation methods, our approach leverages on the simulated player performance data to construct the scenario evaluation function for scenario generation. To collect the player performance data, an artificial intelligence (AI) player model is designed to imitate how a human player behaves when playing scenarios. The AI players are used to replace human players for data collection. The experiment results show that our data-driven approach provides good prediction accuracy on scenario’s training intensities. It also outperforms our previous heuristic-based approach in its capability of generating scenarios that match closer to specified target player performance
Safety and tolerability of NXY-059 for acute intracerebral hemorrhage: the CHANT trial
<p><b>Background and Purpose:</b> NXY-059 is a free radical-trapping neuroprotectant developed for use in acute ischemic stroke. To facilitate prompt administration of treatment, potentially before neuroimaging, we investigated the safety of NXY-059 in patients with intracerebral hemorrhage (ICH).</p>
<p><b>Methods:</b> We randomized 607 patients within 6 hours of acute ICH to receive 2270 mg intravenous NXY-059 over 1 hour and then up to 960 mg/h over 71 hours, or matching placebo, in addition to standard care. The primary outcome was safety: the mortality and the frequency of adverse events, and the change from baseline for a variety of serum, imaging, and electrophysiological measurements. We also studied the overall distribution of disability scores on the modified Rankin Scale (mRS) and the Barthel index.</p>
<p><b>Results:</b> We treated 300 patients with NXY-059 and 303 with placebo. Treatment groups were well matched for prognostic variables including Glasgow Coma Scale, risk factors, and age. The mean National Institute of Health Stroke Scale score on admission was 14 in both groups. The baseline hemorrhage volume was 22.4±20.1 mL in the NXY-059 group and 23.3±22.8 mL in the placebo group (mean±SD). Most hemorrhages were related to hypertension or anticoagulant use. Mortality was similar in both groups: 20.3% for NXY-059 and 19.8% for placebo-treated patients. The proportion of patients who experienced an adverse event was the same for both groups, whereas for serious adverse events the proportion was slightly higher in the NXY-059 group. However, no pattern emerged to indicate a safety concern. Serum potassium fell transiently in both groups, lower in the NXY-059 group. There were no differences in 3-month function, disability, or neurological deficit scores. The odds ratio for an improved outcome in 3-month mRS scores in the NXY-059 group was 1.01 (95% CI 0.75, 1.35).</p>
<p><b>Conclusions:</b> NXY-059 given within 6 hours of acute ICH has a good safety and tolerability profile, with no adverse effect on important clinical outcomes.</p>
Temperature dependence of the spin and orbital magnetization density in around the spin-orbital compensation point
Non-resonant ferromagnetic x-ray diffraction has been used to separate the
spin and orbital contribution to the magnetization density of the proposed
zero-moment ferromagnet . The alignment of the
spin and orbital moments relative to the net magnetization shows a sign
reversal at 84K, the compensation temperature. Below this temperature the
orbital moment is larger than the spin moment, and vice versa above it. This
result implies that the compensation mechanism is driven by the different
temperature dependencies of the spin and orbital moments. Specific heat
data indicate that the system remains ferromagnetically ordered throughout
Clinical selection strategies to identify ischemic stroke patients with large anterior vessel occlusion: results from SITS-ISTR (Safe Implementation of Thrombolysis in Stroke International Stroke Thrombolysis Registry)
Background and Purpose—The National Institutes of Health Stroke Scale (NIHSS) correlates with presence of large anterior vessel occlusion (LAVO). However, the application of the full NIHSS in the prehospital setting to select patients eligible for treatment with thrombectomy is limited. Therefore, we aimed to evaluate the prognostic value of simple clinical selection strategies.
Methods—Data from the Safe Implementation of Thrombolysis in Stroke International Stroke Thrombolysis Registry (January 2012–May 2014) were analyzed retrospectively. Patients with complete breakdown of NIHSS scores and documented vessel status were included. We assessed the association of prehospital stroke scales and NIHSS symptom profiles with LAVO (internal carotid artery, carotid-terminus or M1-segment of the middle cerebral artery).
Results—Among 3505 patients, 23.6% (n=827) had LAVO. Pathological finding on the NIHSS item best gaze was strongly associated with LAVO (adjusted odds ratio 4.5, 95% confidence interval 3.8–5.3). All 3 face–arm–speech–time test (FAST) items identified LAVO with high sensitivity. Addition of the item gaze to the original FAST score (G-FAST) or high scores on other simplified stroke scales increased specificity. The NIHSS symptom profiles representing total anterior syndromes showed a 10-fold increased likelihood for LAVO compared with a nonspecific clinical profile. If compared with an NIHSS threshold of ≥6, the prehospital stroke scales performed similarly or even better without losing sensitivity.
Conclusions—Simple modification of the face–arm–speech–time score or evaluating the NIHSS symptom profile may help to stratify patients’ risk of LAVO and to identify individuals who deserve rapid transfer to comprehensive stroke centers. Prospective validation in the prehospital setting is required
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