Approximating a Wavefunction as an Unconstrained Sum of Slater Determinants

The wavefunction for the multiparticle Schr\"odinger equation is a function of many variables and satisfies an antisymmetry condition, so it is natural to approximate it as a sum of Slater determinants. Many current methods do so, but they impose additional structural constraints on the determinants, such as orthogonality between orbitals or an excitation pattern. We present a method without any such constraints, by which we hope to obtain much more efficient expansions, and insight into the inherent structure of the wavefunction. We use an integral formulation of the problem, a Green's function iteration, and a fitting procedure based on the computational paradigm of separated representations. The core procedure is the construction and solution of a matrix-integral system derived from antisymmetric inner products involving the potential operators. We show how to construct and solve this system with computational complexity competitive with current methods.Comment: 30 page

Efficient Spherical Harmonic Transforms aimed at pseudo-spectral numerical simulations

In this paper, we report on very efficient algorithms for the spherical harmonic transform (SHT). Explicitly vectorized variations of the algorithm based on the Gauss-Legendre quadrature are discussed and implemented in the SHTns library which includes scalar and vector transforms. The main breakthrough is to achieve very efficient on-the-fly computations of the Legendre associated functions, even for very high resolutions, by taking advantage of the specific properties of the SHT and the advanced capabilities of current and future computers. This allows us to simultaneously and significantly reduce memory usage and computation time of the SHT. We measure the performance and accuracy of our algorithms. Even though the complexity of the algorithms implemented in SHTns are in $O(N^3)$ (where N is the maximum harmonic degree of the transform), they perform much better than any third party implementation, including lower complexity algorithms, even for truncations as high as N=1023. SHTns is available at https://bitbucket.org/nschaeff/shtns as open source software.Comment: 8 page

Electrical Model Validation of Magnetic Cores for Current Sensing and Loop Filter Applications

Exploitation of magnetic materials for Electromagnetic Interference (EMI) filtering applications is inevitable in real inverter applications. In order to evaluate filter design, component characterization is vital and similarly predicting the real behavior of components is mandatory. The design of EMI filter varies case per case, however the utilization of magnetic materials is indispensible, therefore a better understanding of magnetic materials is required. Basic inductor models with parallel RLC circuits are not sufficient to produce an equivalent circuit model, thus information on multi-resonance phenomena along with various parasitic elements is required. This paper discusses a comprehensive validation study where the simulated circuit model will be compared with measurement results obtained from a real electric drive (eDrive) system. Moreover, a comprehensive study for core saturation behavior based on measurement results will be included. The aim of this study is to model an equivalent circuit for magnetic materials which can be employed as current sensors in Active EMI Filter (AEF) applications or as common-mode transformer (CMT) in loop filter applications

The Female Athlete's Heart: Facts and Fallacies.

Purpose of the review For many years, competitive sport has been dominated by men. Recent times have witnessed a significant increase in women participating in elite sports. As most studies investigated male athletes, with few reports on female counterparts, it is crucial to have a better understanding on physiological cardiac adaptation to exercise in female athletes, to distinguish normal phenotypes from potentially fatal cardiac diseases. This review reports on cardiac adaptation to exercise in females. Recent findings Recent studies show that electrical, structural, and functional cardiac changes due to physiological adaptation to exercise differ in male and female athletes. Women tend to exhibit eccentric hypertrophy, and while concentric hypertrophy or concentric remodeling may be a normal finding in male athletes, it should be evaluated carefully in female athletes as it may be a sign of pathology. Although few studies on veteran female athletes are available, women seem to be affected by atrial fibrillation, coronary atherosclerosis, and myocardial fibrosis less than male counterparts. Summary Males and females exhibit many biological, anatomical, and hormonal differences, and cardiac adaptation to exercise is no exception. The increasing participation of women in sports should stimulate the scientific community to develop large, longitudinal studies aimed at a better understanding of cardiac adaptation to exercise in female athletes

Leveraging high-throughput screening data, deep neural networks, and conditional generative adversarial networks to advance predictive toxicology

There are currently 85,000 chemicals registered with the Environmental Protection Agency (EPA) under the Toxic Substances Control Act, but only a small fraction have measured toxicological data. To address this gap, high-throughput screening (HTS) and computational methods are vital. As part of one such HTS effort, embryonic zebrafish were used to examine a suite of morphological and mortality endpoints at six concentrations from over 1,000 unique chemicals found in the ToxCast library (phase 1 and 2). We hypothesized that by using a conditional generative adversarial network (cGAN) or deep neural networks (DNN), and leveraging this large set of toxicity data we could efficiently predict toxic outcomes of untested chemicals. Utilizing a novel method in this space, we converted the 3D structural information into a weighted set of points while retaining all information about the structure. In vivo toxicity and chemical data were used to train two neural network generators. The first was a DNN (Go-ZT) while the second utilized cGAN architecture (GAN-ZT) to train generators to produce toxicity data. Our results showed that Go-ZT significantly outperformed the cGAN, support vector machine, random forest and multilayer perceptron models in cross-validation, and when tested against an external test dataset. By combining both Go-ZT and GAN-ZT, our consensus model improved the SE, SP, PPV, and Kappa, to 71.4%, 95.9%, 71.4% and 0.673, respectively, resulting in an area under the receiver operating characteristic (AUROC) of 0.837. Considering their potential use as prescreening tools, these models could provide in vivo toxicity predictions and insight into the hundreds of thousands of untested chemicals to prioritize compounds for HT testing

Coronary Artery Perforation Following Implantation of a Drug-Eluting Stent Rescued by Deployment of a Covered Stent in Symptomatic Myocardial Bridging

We successfully rescued a patient whose coronary artery perforated following implantation of a drug-eluting stent (DES), by deploying a stent-graft in symptomatic myocardial bridging. Our case demonstrated that coronary perforation could be handled without difficulty when perforated myocardial bridging is confined to the interventricular groov

Coronary atherosclerotic burden in veteran male recreational athletes with low to intermediate cardiovascular risk.

INTRODUCTION: Although there is evidence that a significant proportion of veteran athletes have coronary atherosclerotic disease (CAD), its prevalence in recreational athletes with low to intermediate cardiovascular (CV) risk is not established. This study aimed to characterize the coronary atherosclerotic burden in veteran male recreational athletes with low to intermediate CV risk. METHODS: Asymptomatic male athletes aged ≥40 years with low to intermediate risk, who exercised >4 hours/week for >5 years, underwent cardiac computed tomography (CT) for coronary artery calcium (CAC) scoring and CT angiography. High coronary atherosclerotic burden was defined as at least one of the following: CAC score >100; CAC score ≥75th percentile; obstructive CAD; disease involving the left main, three vessels or two vessels including the proximal left anterior descending artery; segment involvement score >5; or CT Leaman score ≥5. Athletes were categorized by tertiles of exercise volume, calculated by metabolic equivalent of task (MET) scores. RESULTS: A total of 105 athletes were included, all with SCORE 100, 13 (12.4%) had CAC score ≥75th percentile and six (5.7%) had obstructive lesions. The extent and severity of coronary plaques did not differ according to exercise volume. CONCLUSIONS: The prevalence of subclinical CAD detected by cardiac CT in veteran male recreational athletes with low to intermediate CV risk was high. Up to a quarter of our cohort had a high coronary atherosclerotic burden

Screening for proximal coronary artery anomalies with 3-dimensional MR coronary angiography

Under 35 years of age, 14% of sudden cardiac death in athletes is caused by a coronary artery anomaly (CAA). Free-breathing 3-dimensional magnetic resonance coronary angiography (3D-MRCA) has the potential to screen for CAA in athletes and non-athletes as an addition to a clinical cardiac MRI protocol. A 360 healthy men and women (207 athletes and 153 non-athletes) aged 18–60 years (mean age 31 ± 11 years, 37% women) underwent standard cardiac MRI with an additional 3D-MRCA within a maximum of 10 min scan time. The 3D-MRCA was screened for CAA. A 335 (93%) subjects had a technically satisfactory 3D-MRCA of which 4 (1%) showed a malignant variant of the right coronary artery (RCA) origin running between the aorta and the pulmonary trunk. Additional findings included three subjects with ventral rotation of the RCA with kinking and possible proximal stenosis, one person with additional stenosis and six persons with proximal myocardial bridging of the left anterior descending coronary artery. Coronary CT-angiography (CTA) was offered to persons with CAA (the CAA was confirmed in three, while one person declined CTA) and stenosis (the ventral rotation of the RCA was confirmed in two but without stenosis, while two people declined CTA). Overall 3D MRCA quality was better in athletes due to lower heart rates resulting in longer end-diastolic resting periods. This also enabled faster scan sequences. A 3D-MRCA can be used as part of the standard cardiac MRI protocol to screen young competitive athletes and non-athletes for anomalous proximal coronary arteries