2,975 research outputs found
Detection and prediction of clopidogrel treatment failures using longitudinal structured electronic health records
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
Spherical representation and polyhedron routing for load balancing in wireless sensor networks
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
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 Lévy 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 and in and
Using a data sample of decays collected with the BES
II detector at the BEPC, searches for invisible decays of and
in to and are performed.
The signals, which are reconstructed in final states, are used
to tag the and decays. No signals are found for the
invisible decays of either or , and upper limits at the 90%
confidence level are determined to be for the ratio
and for . These are the first
searches for and 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
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 -> and Decays
The system in decays of is limited to be
isospin 1/2 by isospin conservation. This provides a big advantage in studying
compared with and experiments which mix
isospin 1/2 and 3/2 for the system. Using 58 million decays
collected with the Beijing Electron Positron Collider, more than 100 thousand
events are obtained. Besides two well known
peaks at 1500 MeV and 1670 MeV, there are two new, clear peaks in
the invariant mass spectrum around 1360 MeV and 2030 MeV. They are the
first direct observation of the peak and a long-sought "missing"
peak above 2 GeV in the invariant mass spectrum. A simple
Breit-Wigner fit gives the mass and width for the peak as MeV and MeV, and for the new peak above 2 GeV
as MeV and MeV, respectively
Search for D to phi l nu and measurement of the branching fraction for D to phi pi
Using a data sample of integrated luminosity of about 33 pb collected
around 3.773 GeV with the BESII detector at the BEPC collider, the semileptonic
decays , and the hadronic
decay are studied. The upper limits of the branching
fractions are set to be 2.01% and 2.04% at the 90% confidence level. The ratio of the
branching fractions for relative to is measured to be . In addition, the
branching fraction for is obtained to be .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
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 and Inclusive Semileptonic Decays of and Mesons
With singly-tagged 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 decays of and
mesons, which are , , and
, respectively. We have also
measured the branching fractions for the inclusive semileptonic decays of
and mesons to be and . These yield the ratio of their partial
widths to be .Comment: 6 pages, 5 figure
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