2,975 research outputs found

    Detection and prediction of clopidogrel treatment failures using longitudinal structured electronic health records

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    We propose machine learning algorithms to automatically detect and predict clopidogrel treatment failure using longitudinal structured electronic health records (EHR). By drawing analogies between natural language and structured EHR, we introduce various machine learning algorithms used in natural language processing (NLP) applications to build models for treatment failure detection and prediction. In this regard, we generated a cohort of patients with clopidogrel prescriptions from UK Biobank and annotated if the patients had treatment failure events within one year of the first clopidogrel prescription; out of 502,527 patients, 1,824 patients were identified as treatment failure cases, and 6,859 patients were considered as control cases. From the dataset, we gathered diagnoses, prescriptions, and procedure records together per patient and organized them into visits with the same date to build models. The models were built for two different tasks, i.e., detection and prediction, and the experimental results showed that time series models outperform bag-of-words approaches in both tasks. In particular, a Transformer-based model, namely BERT, could reach 0.928 AUC in detection tasks and 0.729 AUC in prediction tasks. BERT also showed competence over other time series models when there is not enough training data, because it leverages the pre-training procedure using large unlabeled data

    Load balanced short path routing in large-scale wireless networks using area-preserving maps

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    Spherical representation and polyhedron routing for load balancing in wireless sensor networks

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    Abstract—In this paper we address the problem of scalable and load balanced routing for wireless sensor networks. Motivated by the analog of the continuous setting that geodesic routing on a sphere gives perfect load balancing, we embed sensor nodes on a convex polyhedron in 3D and use greedy routing to deliver messages between any pair of nodes with guaranteed success. This embedding is known to exist by the Koebe-Andreev-Thurston Theorem for any 3-connected planar graphs. In our paper we use discrete Ricci flow to develop a distributed algorithm to compute this embedding. Further, such an embedding is not unique and differs from one another by a Möbius transformation. We employ an optimization routine to look for the Möbius transformation such that the nodes are spread on the polyhedron as uniformly as possible. We evaluated the load balancing property of this greedy routing scheme and showed favorable comparison with previous schemes. I

    A solar irradiance estimation technique via curve fitting based on dual-mode Jaya optimization

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    Solar irradiance is a crucial environmental parameter for optimal control of photovoltaic (PV) systems. However, precise measurements of the solar irradiance are difficult since the irradiation sensors (i.e., pyranometer or pyrheliometer) are expensive and hard to calibrate. This paper proposes a cost-effective and accurate method for estimating the solar irradiance with a PV module via curve fitting. A dual-mode Jaya (DM-Jaya) optimization algorithm is introduced to extract the real-time value of solar irradiance from the measured PV characteristics data by using two search strategies. The step sizes of a random walk are taken from even and LĂ©vy distribution distributions in different searching phases. Compared with the traditional irradiance sensors, the proposed estimator does not require additional circuit and obtains relatively lower error rates. A comparative study of seven population-based optimization algorithms for the optimal design of the estimator is presented. These algorithms include particle swarm optimization (PSO), cuckoo search (CS), Jaya, simulated annealing (SA), genetic algorithm (GA), supply-demand-based optimization (SDO), and the proposed DM-Jaya algorithm. Simulations and experimental results reveal that DM-Jaya outperforms the other optimization algorithms in terms of the estimation speed and accuracy

    Search for Invisible Decays of η\eta and ηâ€Č\eta^\prime in J/ψ→ϕηJ/\psi \to \phi\eta and ϕηâ€Č\phi \eta^\prime

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    Using a data sample of 58×10658\times 10^6 J/ψJ/\psi decays collected with the BES II detector at the BEPC, searches for invisible decays of η\eta and ηâ€Č\eta^\prime in J/ψJ/\psi to ϕη\phi\eta and ϕηâ€Č\phi\eta^\prime are performed. The ϕ\phi signals, which are reconstructed in K+K−K^+K^- final states, are used to tag the η\eta and ηâ€Č\eta^\prime decays. No signals are found for the invisible decays of either η\eta or ηâ€Č\eta^\prime, and upper limits at the 90% confidence level are determined to be 1.65×10−31.65 \times 10^{-3} for the ratio B(η→invisible)B(η→γγ)\frac{B(\eta\to \text{invisible})}{B(\eta\to\gamma\gamma)} and 6.69×10−26.69\times 10^{-2} for B(ηâ€Č→invisible)B(ηâ€Č→γγ)\frac{B(\eta^\prime\to \text{invisible})}{B(\eta^\prime\to\gamma\gamma)}. These are the first searches for η\eta and ηâ€Č\eta^\prime decays into invisible final states.Comment: 5 pages, 4 figures; Added references, Corrected typo

    Does robot-assisted laparoscopic radical prostatectomy enable to obtain adequate oncological and functional outcomes during the learning curve? From the Korean experience

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    To estimate the short-term results of robot-assisted laparoscopic radical prostatectomy (RALRP) during the learning curve, in terms of surgical, oncological and functional outcomes, we conducted a prospective survey on RALRP. From July 2007, a single surgeon performed 63 robotic prostatectomies using the same operative technique. Perioperative data, including pathological and early functional results of the patient, were collected prospectively and analyzed. Along with the accumulation of the cases, the total operative time, setup time, console time and blood loss were significantly decreased. No major complication was present in any patient. Transfusion was needed in six patients; all of them were within the initial 15 cases. The positive surgical margin rate was 9.8% (5/51) in pT2 disease. The most frequent location of positive margin in this stage was the lateral aspect (60%), but in pT3 disease multiple margins were the most frequent (41.7%). Overall, 53 (84.1%) patients had totally continent status and the median time to continence was 6.56 weeks. Among 17 patients who maintained preoperative sexual activity ( Sexual Health Inventory for Men \u3e = 17), stage below pT2, followed up for \u3e 6 months with minimally one side of neurovascular bundle preservation procedure, 12 (70.6%) were capable of intercourse postoperatively, and the mean time for sexual intercourse after operation was 5.7 months. In this series, robotic prostatectomy was a feasible and reproducible technique, with a short learning curve and low perioperative complication rate. Even during the initial phase of the learning curve, satisfactory results were obtained with regard to functional and oncological outcome

    Observation of Two New N* Peaks in J/psi -> ppi−nˉp pi^- \bar n and pˉπ+n\bar p\pi^+n Decays

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    The πN\pi N system in decays of J/ψ→NˉNπJ/\psi\to\bar NN\pi is limited to be isospin 1/2 by isospin conservation. This provides a big advantage in studying N∗→πNN^*\to \pi N compared with πN\pi N and ÎłN\gamma N experiments which mix isospin 1/2 and 3/2 for the πN\pi N system. Using 58 million J/ψJ/\psi decays collected with the Beijing Electron Positron Collider, more than 100 thousand J/ψ→pπ−nˉ+c.c.J/\psi \to p \pi^- \bar n + c.c. events are obtained. Besides two well known N∗N^* peaks at 1500 MeV and 1670 MeV, there are two new, clear N∗N^* peaks in the pπp\pi invariant mass spectrum around 1360 MeV and 2030 MeV. They are the first direct observation of the N∗(1440)N^*(1440) peak and a long-sought "missing" N∗N^* peak above 2 GeV in the πN\pi N invariant mass spectrum. A simple Breit-Wigner fit gives the mass and width for the N∗(1440)N^*(1440) peak as 1358±6±161358\pm 6 \pm 16 MeV and 179±26±50179\pm 26\pm 50 MeV, and for the new N∗N^* peak above 2 GeV as 2068±3−40+152068\pm 3^{+15}_{-40} MeV and 165±14±40165\pm 14\pm 40 MeV, respectively

    Search for D to phi l nu and measurement of the branching fraction for D to phi pi

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    Using a data sample of integrated luminosity of about 33 pb−1^{-1} collected around 3.773 GeV with the BESII detector at the BEPC collider, the semileptonic decays D+→ϕe+ÎœeD^+ \to \phi e ^+\nu_e, D+→ϕΌ+ΜΌD^+ \to \phi \mu^+\nu_\mu and the hadronic decay D+→ϕπ+D^+ \to \phi \pi^+ are studied. The upper limits of the branching fractions are set to be BF(D+→ϕe+Îœe)<BF(D^+ \to \phi e ^+\nu_e) < 2.01% and BF(D+→ϕΌ+ΜΌ)<BF(D^+ \to \phi \mu^+ \nu_\mu) < 2.04% at the 90% confidence level. The ratio of the branching fractions for D+→ϕπ+D^+ \to \phi \pi^+ relative to D+→K−π+π+D^+ \to K^-\pi^+\pi^+ is measured to be 0.057±0.011±0.0030.057 \pm 0.011 \pm 0.003. In addition, the branching fraction for D+→ϕπ+D^+ \to \phi \pi^+ is obtained to be (5.2±1.0±0.4)×10−3(5.2 \pm 1.0 \pm 0.4) \times 10^{-3}.Comment: 6 pages, 5 figures, to be published in Eur.Phys.J.

    Measurements of branching fractions for inclusive K0~/K0 and K*(892)+- decays of neutral and charged D mesons

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    Using the data sample of about 33 pb-1 collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, we have studied inclusive K0~/K0 and K*(892)+- decays of D0 and D+ mesons. The branching fractions for the inclusive K0~/K0 and K*(892)- decays are measured to be BF(D0 to K0~/K0 X)=(47.6+-4.8+-3.0)%, BF(D+ to K0~/K0 X)=(60.5+-5.5+-3.3)%, BF(D0 to K*- X)=(15.3+- 8.3+- 1.9)% and BF(D+ to K*- X)=(5.7+- 5.2+- 0.7)%. The upper limits of the branching fractions for the inclusive K*(892)+ decays are set to be BF(D0 to K*+ X)<3.6% and BF(D+ to K*+ X) <20.3% at 90% confidence level

    Direct Measurements of the Branching Fractions for Inclusive K±K^\pm and Inclusive Semileptonic Decays of D+D^+ and D0D^0 Mesons

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    With singly-tagged Dˉ\bar D samples selected from the data collected at and around 3.773 GeV with the BESII detector at the BEPC collider, we have measured the branching fractions for the inclusive K±K^\pm decays of D+D^+ and D0D^0 mesons, which are BF(D+→K−X)=(24.7±1.3±1.2)BF(D^+\to K^-X) = (24.7 \pm 1.3 \pm 1.2)%, BF(D+→K+X)=(6.1±0.9±0.4)BF(D^+\to K^+X) = (6.1 \pm 0.9 \pm 0.4) %, BF(D0→K−X)=(57.8±1.6±3.2)BF(D^0\to K^-X) = (57.8 \pm 1.6 \pm 3.2) % and BF(D0→K+X)=(3.5±0.7±0.3)BF(D^0\to K^+X) = (3.5 \pm 0.7 \pm 0.3) %, respectively. We have also measured the branching fractions for the inclusive semileptonic decays of D+D^+ and D0D^0 mesons to be BF(D+→e+X)=(15.2±0.9±0.8)BF(D^+ \to e^+ X)=(15.2 \pm 0.9 \pm 0.8)% and BF(D0→e+X)=(6.3±0.7±0.4)BF(D^0 \to e^+ X) =(6.3 \pm 0.7 \pm 0.4) %. These yield the ratio of their partial widths to be Γ(D+→e+X)/Γ(D0→e+X)=0.95±0.12±0.07\Gamma(D^+ \to e^+X)/\Gamma(D^0 \to e^+X)=0.95 \pm 0.12 \pm 0.07.Comment: 6 pages, 5 figure
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