Complex Rotation Research Articles

Doubly excited states of the positronium molecule

The projection method with explicitly correlated Gaussians is used to demonstrate the existence of two doubly excited states of the positronium molecule (${\mathrm{Ps}}_{2}$). One is below the $\mathrm{Ps}(n=2)\phantom{\rule{4pt}{0ex}}+\phantom{\rule{4pt}{0ex}}\mathrm{Ps}(n=2)$ threshold, with ${A}_{1}$ symmetry, and the other is below the $\mathrm{Ps}(n=2)+\mathrm{Ps}(n=3)$ threshold, with $E$ symmetry. These states exist as resonances in the Ps-Ps continuum. Moreover, the resonance positions and resonance widths of the two states are calculated using the complex rotation method with basis sets obtained via the orthogonalizing pseudoprojector method. The resonance positions obtained using the complex rotation method agree with the results of the orthogonalizing pseudoprojector method. We also investigate the various structural properties of these states as well as the decay probabilities of $2\ensuremath{\gamma}$ emission due to electron-positron annihilation.

Application of membrane anatomy in key technologies during gastric cancer surgery: guidance and compromise

Different from classical surgical anatomy which only pays attention to the morphology and structure of human organs, modern membrane anatomy focuses on not only the relationship between morphology and structure, but also the biological behavior characteristics of tumors. Membrane antomy is a theoretical system with interpretation on both the structural and disease function, so it has been accepted by more and more gastrointestinal surgeons. However, the theoretical system of gastric membrane anatomy is not mature yet. The stomach and its mesentery have undergone complex rotation and fusion in the process of embryonic development, so that surgeons have different understandings of the gastric membrane anatomy. Therefore, it is easy to cause various confusion and misunderstanding, resulting in deviations between the theory of membrane anatomy and the practice of surgery. In the present study, the mesentery of the stomach is divided into different regions, and the embryonic development process is traced back. The application and compromise encountered in the radical gastrectomy of gastric cancer will be expounded according to the membrane anatomy theory combined with the author's experience of operation.

W2020: A Database of Validated Rovibrational Experimental Transitions and Empirical Energy Levels of H216O

A detailed understanding of the complex rotation–vibration spectrum of the water molecule is vital for many areas of scientific and human activity, and thus, it is well studied in a number of spectral regions. To enhance our perception of the spectrum of the parent water isotopologue, H216O, a dataset of 270 745 non-redundant measured transitions is assembled, analyzed, and validated, yielding 19 204 rovibrational energy levels with statistically reliable uncertainties. The present study extends considerably an analysis of the rovibrational spectrum of H216O, published in 2013, by employing an improved methodology, considering about one-third more new observations (often with greatly decreased uncertainties), and using a highly accurate first-principles energy list for validation purposes. The database of experimental rovibrational transitions and empirical energy levels of H216O created during this study is called W2020. Some of the new transitions in W2020 allow the improved treatment of many parts of the dataset, especially considering the uncertainties of the experimental line positions and the empirical energy values. The W2020 dataset is examined to assess where measurements are still lacking even for this most thoroughly studied isotopologue of water, and to provide definitive energies for the lower and upper states of many yet-to-be-measured transitions. The W2020 dataset allows the evaluation of several previous compilations of spectroscopic data of water and the accuracy of previous effective Hamiltonian fits.

Chiral motion in colloidal electrophoresis.

Asymmetrically charged, nonspherical colloidal particles in general perform complex rotations and oblique motions under an electric field. The interplay of electrostatic and hydrodynamic forces complicates the prediction of these motions. We demonstrate a method of calculating the body tensors that dictate translational and rotational velocity vectors arising from an external electric field. We treat insulating rigid bodies in the linear-response regime, with indefinitely small electrostatic screening length. The method represents the body as an assembly of point sources of both hydrodynamic drag and surface electric field. We demonstrate agreement with predicted electrophoretic mobility to within a few percent for several shapes with uniform and nonuniform charges. We show that even symmetric shapes can have strong chiral twisting motions. The method applies more generally to active colloidal swimmers.

Intraprocedural guidance for recanalization of post-thrombotic venous lesions using live overlay of center lines from pre-operative cross-sectional imaging: a preliminary experience

PurposePre-procedural contrast-enhanced CT and MRI imaging is typically acquired prior to deep venous recanalization procedures for post-thrombotic syndrome. This technical note reports the utility of live-overlay of augmented centerlines extracted from pre-procedural CT and MRI imaging in facilitating fluoroscopic-guided recanalization of post-thrombotic venous lesions.Methods and materialsSix patients with pre-procedural CT or MR venography data were incorporated into a commercially available 3D overlay software (Vessel Assist, GE Healthcare, Buc, France) during venous disease interventions for post-thrombotic venous lesions. Procedures were performed on the GE Discovery IGS 740 fluoroscopy system. After manual determination of the vasculature from preprocedural CT or MR, centerlines were created representing the location and trajectory of the vessels. Steps showcasing the creation of centerlines and their representation during overlay with real-time fluoroscopic guidance in these cases are outlined. Time required to cross the post-thrombotic and occlusive venous segments were reviewed.ResultsAll iliocaval recanalization procedures were successfully performed utilizing vessel centerline 3D overlay. In one case where occlusion extended to the femoral vein, mis-registration was identified over the femoral anatomy due to a complex leg rotation compared to pre-procedural imaging. No procedural complications related to utilization of software were noted. Average crossing time for occlusions was 3.4 min (range 1.6–5.2).Conclusion3D overlay with vessel tracking from pre-procedural CT and MRI imaging is technically feasible and assists in catheter navigation for post-thrombotic venous segments. While results from these preliminary experiences support the continued use of this technology, further prospective and comparative evaluation of this technique is warranted to assess for added value in technical success, reductions in procedure time or reductions in radiation exposure.

Rotation of the maxillomandibular complex in orthognathic surgery; A Review

Introduction: In orthognathic surgery, maxillomandibular complex (MMC) refers to a three-dimensional dento-osseous structure consisting of the surgically-mobilized part of the maxilla together with the distal segment (i.e., tooth bearing segment) of the mandible (either surgically mobilized or not). In fact, MMC is the skeletal part of the lower face. The size, shape And position of MMC play a major role in soft tissue esthetics of the lower face. Materials and methods: A comprehensive review of the current data regarding effects of maxillomandibular complex rotation in sagittal plane, on “occlusal plane, TMJ, sleep apnea, paranasal soft tissues, upper lip, chin, cervicomental soft tissues” was conducted. Results: MMC rotation and translation could take place in any of the three planes of reference including sagittal, coronal, and horizontal. Any kind of changes in the position of MMC could have its own functional and esthetic consequences. In general, patients with convex facial profiles require counterclockwise rotation while patients with concave profiles require clockwise rotation. Conclusion: MMC not only has great impacts on facial esthetics, but also has significant functional effects, for example in breathing and mastication. Alteration in the position of MMC is possible by orthognathic surgery.

A Novel Paradigm of CORDIC-Based FFT Architecture Framed on the Optimality of High-Radix Computation

‘Fast Fourier transform’ (FFT), being a prevalent algorithm for the proficient computation of ‘discrete Fourier transform,’ constitutes one of the major sub-modules in numerous real-time signal processing systems. In this article, a new approach of CORDIC-based high-radix FFT architecture has been demonstrated. Having identified the complex rotation as the most time-consuming elementary operation of FFT, the number of such complex rotations has been optimized by adopting radix-8-based FFT computation. To add to this, CORDIC is employed to realize the complex rotation, keeping aside its multiplier–accumulator (MAC)-based counterpart, for further economizing the VLSI implementation of the proposed FFT architecture. Furthermore, the requirement of CORDIC blocks for last three stages of radix-8 FFT computation has totally been mitigated by utilizing SCALE blocks as the rotation in those stages can be expressed in terms of $$\pi /4$$ or its multiples. RAM is arranged in the form of memory banks to provide parallel data path operations, and RAM switching is performed in between stages for sustaining continuous data flow circumventing data access hazards. The throughput of the proposed radix-8 architecture is eight outputs per clock cycle, while the maximum clock frequency is limited only by the propagation delay of an adder. Hardware utilization and comparative performance evaluation have been reported to prove the proposed architecture’s supremacy. Our proposed prototype radix-8 architecture has been successfully implemented on Zynq UltraScale+ FPGA using Xilinx Vivado 18.2 software for verifying its feasibility in practical applications.

ESR, STESR, DFT, and MD Study of the Dynamical Structure of Cucurbituril[7]-Spin Probe Guest-Host Complexes.

We study the molecular dynamics and structures of the guest–host complexes of cucurbituril, CB[7], with spin probes through the conventional electron spin resonance (ESR), saturation transfer ESR (STESR), density functional theory (DFT), and molecular dynamics (MD) computations. Protonated TEMPOamine (I), a derivative of TEMPO having a positive charge and an octyl group on the quaternary nitrogen atom (II), and the neutral spin-labeled indole (III) are used as guests. To eliminate the overall complex rotation, the solutions of complexes in a solid CB[7] matrix were prepared. Resultantly, for all of the spin probes, the combined study of the conventional ESR and STESR spectra indicates the librational character of the rotational motion within the CB[7] cavity as opposed to the diffusional rotation over the whole solid angle. The kinetic accessibilities of the reporter NO groups to the paramagnetic complexes in aqueous solutions, determined by Heisenberg exchange broadening of the ESR spectra, together with the environment polarities from the hyperfine interaction values, as well as DFT computation results and MD simulations, were used to estimate the spin probe location relative to CB[7]. Utilizing the concept of the aqueous clusters surrounding the spin probes and CB[7] molecules and MD simulations has allowed the application of DFT to estimate the aqueous environment effects on the complexation energy and spatial structure of the guest–host complexes.

Complex Rotated Relativistic Configuration-Interaction Calculations of 1s2l2l ' States in O5+ Ion

Relativistic calculations of the energies and Auger widths of the lowest autoionizing states of lithium-like oxygen are performed. All leading corrections to the energy, including the contribution of electronic correlations, nuclear recoil effect, and quantum electrodynamic (QED) corrections, are included. The calculations have been performed using the Dirac–Coulomb–Breit Hamiltonian by the method of configuration interaction with complex rotation. The results obtained have been compared with the known experimental and theoretical values.

Constraining the Einstein equivalence principle with multi-wavelength observations of polarized blazars

ABSTRACT In this paper, we present a novel method to test the Einstein equivalence principle (EEP) using (simultaneous) multi-wavelength radio observations of polarized blazars. We analyse simultaneous multi-wavelength polarization observations of 3C 279 at 22, 43, and 86 GHz obtained by two antennas of the Korean VLBI Network. We obtained 15 groups of polarization data, and applied the Metropolis–Hastings Markov chain (MHMC) to simulate the parameters when considering the EEP effect and the simplest form of Faraday rotation (single external Faraday screen). The final results show the constraint of the parametrized post-Newtonian (PPN) parameter γ discrepancy as Δγp = (1.91 ± 0.34) × 10−20. However, the single external Faraday screen is an oversimplification for blazars because there are numerous observations showing complex Faraday rotation behaviour for blazars due to internal/external Faraday dispersion, beam depolarization, etc. The Δγp results of this paper can only be considered as upper limits. Only if all other effects are revealed and considered should the result be taken as a direct measurement of the violation of the EEP.

Investigation of the doubly excited resonance series of the O6+ ion under the N = 3 threshold of O7+

We theoretically investigate the doubly excited resonance series of the O6+ ion converging towards the N = 3 threshold. No experimental measurements of the energy positions E and the widths Γ for the states belonging to the different series have been reported so far. On the theoretical side, the existing results are rare and not in a perfect agreement. We report in this work accurate results of the resonant parameters (E, Γ) for the resonance states of the ion obtained by using a B-spline based spectral approach combined with the complex rotation method. Our method has the numerical advantage to generate the resonant parameters in a single calculation. It also allows the identification of the states that share similar angular correlation pattern, which helps in their classification into distinct series. Results of the resonant parameters for the high-lying states are being reported for the first time.

Multistable circular currents of polariton condensates trapped in ring potentials.

We demonstrate the formation and trapping of different stationary solutions, oscillatory solutions, and rotating solutions of a polariton condensate in a planar semiconductor microcavity with a built-in ring-shaped potential well. Multistable ring-shaped solutions are trapped in shallow potential wells. These solutions have the same ring-shaped density distribution but different topological charges, corresponding to different orbital angular momentum (OAM) of the emitted light. For stronger confinement potentials, besides the fundamental modes, higher excited (dipole) modes can also be trapped. If two modes are excited simultaneously, their beating produces a complex oscillation or rotation dynamics. When the two modes have the same OAM, a double-ring solution forms for which the density oscillates between the inner and the outer ring. When the two modes have different OAM, a rotating solution with fractional OAM is created.

Chinampas: An Urban Farming Model of the Aztecs and a Potential Solution for Modern Megalopolis

Urban horticulture is not as new as many people think. Throughout history, different techniques have been used to ensure sustainable urban agricultural production. A good example of this is the chinampa system, which was developed during the time of the Aztecs in the region of Lake Xochimilco, south of Mexico City. A chinampa is a raised field on a small artificial island on a freshwater lake surrounded by canals and ditches. Farmers use local vegetation and mud to construct chinampas. Fences made of a native willow [bonpland willow (Salix bonplandiana)] protect the chinampa from wind, pests, and erosion. The dominating crops are vegetables and ornamentals. The canal water that rises through capillarity to the crops reduces the need for additional irrigation. A considerable portion of the fertility in the soils is system-immanent and generated in the aquatic components of the chinampa. Complex rotations and associations allow up to seven harvests per year. Chinampas also provide ecosystem services, particularly greenhouse gas sequestration and biodiversity diversification, and they offer high recreational potential. Recently, research and community initiatives have been performed to try to recover the productive potential of chinampas and align this sustainable system with the needs of the 21st century. In other parts of the world, some with a history of raised field agriculture, similar efforts are being made. The chinampa model could help supply food and ecosystem services in large cities on or near swamplands, large rivers, or lakes.

Dynamic Analysis of Tippe Top on Cylinder’s Inner Surface With and Without Friction based on Routh Reduction

Physics computing can be used to help to solve complex dynamic equations, both translation and rotation. The purpose of this study was to obtain differences in the dynamics of the tippe top with and without friction moving on inner surface of a cylindrical with varying initial state based of Routhian Reduction. The equation of tippe top in flat fields with and without friction has been reduced by the Routhian reduction method with the Poincare equation with computational in the previous research, and computation has also been carried out in the search for numerical solutions to the dynamics of tippe top with friction in the Maple program. In this study the reduction used is a Routhian reduction, so that the equation used in determining the equations of tippe top motion with and without friction that moves in a curved plane in the form of a cylindrical surface with varying initial state based on maple is Poincaré’s equation based on Routhian reduction with and without friction. The effect of friction can be seen clearly through the dynamics and graph equations in the return top. This method can reduce the equation of backward motion with and without friction that moves on the surface of the cylinder clearly in the form of a set of differential equations. This research can be continued by solving the dynamic equations of the tippe top in other curved fields such as the torus and ball. The findings of this study are dynamic equations and graphs of friction with and without friction equations that move in curved fields in the inner of surfaces in cylinders with varying initial state based on maple.

Consumer and Strategic Firm Response to Nutrition Shelf Labels

The display of nutrition facts is mandatory on virtually all packaged foods sold in the United States. Yet manufacturers and retailers add their own claims to differentiate their products and capture consumers' attention at point of sale. We implement experimental nutrition claims on shelf labels in a retail setting and test how consumers react to the display of these labels that express information reported on the Nutrition Facts Panel in a different format. We hypothesize that our labels either shift demand for the highlighted healthier products uniformly or trigger more complex demand rotations. Our estimated heterogeneous labeling effects suggest that consumers process nutrition information differently depending on which and how many claims are displayed and prefer products labeled with a single claim overall. When we simultaneously consider demand and supply responses under three price setting behaviors (competitive pricing, Bertrand‐Nash pricing, and monopoly pricing), we find that consumer surplus and overall welfare is highest when our labels display multiple nutrient claims and retailers are able to adjust prices across the entire product category. Firms' profits are highest when single nutrient claims are displayed, however. We conclude that firms with market power have little incentive to voluntarily display nutrition claims that maximize welfare.

Online Semantic Subspace Learning with Siamese Network for UAV Tracking

In urban environment monitoring, visual tracking on unmanned aerial vehicles (UAVs) can produce more applications owing to the inherent advantages, but it also brings new challenges for existing visual tracking approaches (such as complex background clutters, rotation, fast motion, small objects, and realtime issues due to camera motion and viewpoint changes). Based on the Siamese network, tracking can be conducted efficiently in recent UAV datasets. Unfortunately, the learned convolutional neural network (CNN) features are not discriminative when identifying the target from the background/clutter, In particular for the distractor, and cannot capture the appearance variations temporally. Additionally, occlusion and disappearance are also reasons for tracking failure. In this paper, a semantic subspace module is designed to be integrated into the Siamese network tracker to encode the local fine-grained details of the target for UAV tracking. More specifically, the target’s semantic subspace is learned online to adapt to the target in the temporal domain. Additionally, the pixel-wise response of the semantic subspace can be used to detect occlusion and disappearance of the target, and this enables reasonable updating to relieve model drifting. Substantial experiments conducted on challenging UAV benchmarks illustrate that the proposed method can obtain competitive results in both accuracy and efficiency when they are applied to UAV videos.

Towards interpretable and robust hand detection via pixel-wise prediction

The lack of interpretability of existing CNN-based hand detection methods makes it difficult to understand the rationale behind their predictions. In this paper, we propose a novel neural network model, which introduces interpretability into hand detection for the first time. The main improvements include: (1) Detect hands at pixel level to explain what pixels are the basis for its decision and improve transparency of the model. (2) The explainable Highlight Feature Fusion block highlights distinctive features among multiple layers and learns discriminative ones to gain robust performance. (3) We introduce a transparent representation, the rotation map, to learn rotation features instead of complex and non-transparent rotation and derotation layers. (4) Auxiliary supervision accelerates the training process, which saves more than 10 h in our experiments. Experimental results on the VIVA and Oxford hand detection and tracking datasets show competitive accuracy of our method compared with state-of-the-art methods with higher speed. Models and code are available: https://isrc.iscas.ac.cn/gitlab/research/pr2020-phdn.

Nondispersive wave packets in planar helium

Two-electron wave packets found in driven planar helium follow a classical periodic orbit without spreading and are localized in nonlinear resonance islands of the classical phase space. The general mechanism that produces these nondispersive wave packets is the near-resonant coupling between highly correlated, asymmetric, and doubly excited states of the atom with an external periodic electromagnetic field. We provide a full characterization of these two-electron nondispersive wave packets found in the Floquet spectrum of driven planar helium. This includes the characteristic energy spectrum, relatively long lifetimes, and the identification of the resonance states of helium that are responsible for their formation. This is achieved with the help of an efficient quantum treatment of driven planar helium which combines Floquet theory, complex rotation, and the representation of the Hamiltonian in a set of four coupled harmonic oscillators.

A Two-Phase Stowage Approach for Passenger-Cargo RoRo Ship Based on 2D-KP: Coping With Complex Rotation and Safe Navigation Constraints

The passenger-cargo Roll on/Roll off ship stowage (PRSS) is the core step of passenger-cargo Roll on/Roll off (RoRo) transportation. The layout of vehicles in the cabin is directly related to the space utilization of the cabin and the efficiency of stowage operations, which in turn affects the economic benefits of the port. In this paper, we address the PRSS problem in the context of passenger-cargo RoRo transportation in the Qiongzhou Strait of China. By focusing on the utilization ratio of the cabin area, the PRSS problem can be viewed as a special version of a two-dimensional knapsack packing (2D-KP) problem with additional constraints, such as two-phase, complex rotation and safe navigation constraints. Then we present a mixed integer linear programming (MILP) mathematical model and an algorithm framework to tackle the PRSS problem. In the algorithm framework, a novel multi-phase heuristic stowage method is proposed to improve the current manual stowage decision-making state which completely depends on operational experience. Finally, several instances are generated based on the realistic date of Qiongzhou Strait to verify the effectiveness of the model and stowage method. Computational results show that the proposed model and stowage method are well suited to solve the PRSS problem and the algorithm framework has a strong robustness in large-scale application experiments.

Regenerative agriculture for food and climate

C an regenerative agriculture (RA) produce an adequate amount of nutritious food for the growing and increasingly affluent world population while also reducing and offsetting some anthropogenic emissions? The question may be reframed: how can RA be adapted to produce enough food, be a negative emission technology, and advance Sustainable Development Goals of the United Nations (2015)? System-based RA reconciles the need of producing adequate and nutritious food with the necessity of restoring the environment, making farming a solution to environmental issues. It encompasses a wide range of farming and grazing practices aimed at restoration and sustainable management of soil health through sequestration of soil organic carbon (C). There is no one-size-fits-all practice for diverse soils and ecoregions. RA comprises system-based conservation agriculture (CA), which includes no-till farming in conjunction with residue mulching, cover cropping, integrated nutrient and pest management, complex rotations, and integration of crops with trees and livestock (figure 1) (Lal 2015). RA is all inclusive, and its site-specific package(s) must be fine-tuned in the context of biophysical factors and the human dimensions. RA is soil-centric …