143 research outputs found
Minimal molecular building blocks for screening in quasi-two-dimensional organic–inorganic lead halide perovskites
Layered hybrid organic–inorganic lead halide perovskites have intriguing optoelectronic properties, but some of the most interesting perovskite systems, such as defective, disordered, or mixed perovskites, require multiple unit cells to describe and are not accessible within state-of-the-art ab initio theoretical approaches for computing excited states. The principal bottleneck is the calculation of the dielectric matrix, which scales formally as O(N4). We develop here a fully ab initio approximation for the dielectric matrix, known as IPSA-2C, in which we separate the polarizability of the organic/inorganic layers into minimal building blocks, thus circumventing the undesirable power-law scaling. The IPSA-2C method reproduces the quasi-particle band structures and absorption spectra for a series of Ruddlesden–Popper perovskites to high accuracy, by including critical nonlocal effects neglected in simpler models, and sheds light on the complicated interplay of screening between the organic and inorganic sublattices
Embodied Metaphors and Creative “Acts”
Creativity is a highly sought after skill. To inspire people’s creativity, prescriptive advice in the form of metaphors abound: We are encouraged to think outside the box, to consider the problem on one hand, then on the other hand, and to put two and two together to achieve creative breakthroughs. These metaphors suggest a connection between concrete bodily experiences and creative cognition. Inspired by recent advances on body-mind linkages under the emerging vernacular of embodied cognition, we explored for the first time whether enacting metaphors for creativity enhances creative problem-solving. In five studies, findings revealed that both physically and psychologically embodying creative metaphors promote fluency, flexibility, and/or originality in problem-solving. Going beyond prior research that focused primarily on the kind of embodiment that primes preexisting knowledge, we provide the first evidence that embodiment can also activate cognitive processes conducive for generating previously unknown ideas and connections
CSF and Brain Structural Imaging Markers of the Alzheimer's Pathological Cascade
10.1371/journal.pone.0047406PLoS ONE712
A decade in review after Idiopathic Scoliosis was first called a complex trait-A tribute to the late Dr. Yves Cotrel for his support in studies of etiology of scoliosis
Adolescent Idiopathic Scoliosis (AIS) is a prevalent and important spine disorder in the pediatric age group. An increased family tendency was observed for a long time, but the underlying genetic mechanism was uncertain. In 1999, Dr. Yves Cotrel founded the Cotrel Foundation in the Institut de France, which supported collaboration of international researchers to work together to better understand the etiology of AIS. This new concept of AIS as a complex trait evolved in this setting among researchers who joined the annual Cotrel meetings. It is now over a decade since the first proposal of the complex trait genetic model for AIS. Here, we review in detail the vast information about the genetic and environmental factors in AIS pathogenesis gathered to date. More importantly, new insights into AIS etiology were brought to us through new research data under the perspective of a complex trait. Hopefully, future research directions may lead to better management of AIS, which has a tremendous impact on affected adolescents in terms of both physical growth and psychological development
A decade in review after Idiopathic Scoliosis was first called a complex trait-A tribute to the late Dr. Yves Cotrel for his support in studies of etiology of scoliosis
Adolescent Idiopathic Scoliosis (AIS) is a prevalent and important spine disorder in the pediatric age group. An increased family tendency was observed for a long time, but the underlying genetic mechanism was uncertain. In 1999, Dr. Yves Cotrel founded the Cotrel Foundation in the Institut de France, which supported collaboration of international researchers to work together to better understand the etiology of AIS. This new concept of AIS as a complex trait evolved in this setting among researchers who joined the annual Cotrel meetings. It is now over a decade since the first proposal of the complex trait genetic model for AIS. Here, we review in detail the vast information about the genetic and environmental factors in AIS pathogenesis gathered to date. More importantly, new insights into AIS etiology were brought to us through new research data under the perspective of a complex trait. Hopefully, future research directions may lead to better management of AIS, which has a tremendous impact on affected adolescents in terms of both physical growth and psychological development
Two-qubit spectroscopy of spatiotemporally correlated quantum noise in superconducting qubits
Noise that exhibits significant temporal and spatial correlations across
multiple qubits can be especially harmful to both fault-tolerant quantum
computation and quantum-enhanced metrology. However, a complete spectral
characterization of the noise environment of even a two-qubit system has not
been reported thus far. We propose and experimentally validate a protocol for
two-qubit dephasing noise spectroscopy based on continuous control modulation.
By combining ideas from spin-locking relaxometry with a statistically motivated
robust estimation approach, our protocol allows for the simultaneous
reconstruction of all the single-qubit and two-qubit cross-correlation spectra,
including access to their distinctive non-classical features. Only single-qubit
control manipulations and state-tomography measurements are employed, with no
need for entangled-state preparation or readout of two-qubit observables. While
our experimental validation uses two superconducting qubits coupled to a shared
engineered noise source, our methodology is portable to a variety of
dephasing-dominated qubit architectures. By pushing quantum noise spectroscopy
beyond the single-qubit setting, our work paves the way to characterizing
spatiotemporal correlations in both engineered and naturally occurring noise
environments.Comment: total: 22 pages, 7 figures; main: 13 pages, 6 figures, supplementary:
6 pages, 1 figure; references: 3 page
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Unique local bone tissue characteristics in iliac crest bone biopsy from adolescent idiopathic scoliosis with severe spinal deformity
Adolescent idiopathic scoliosis is a complex disease with unclear etiopathogenesis. Systemic and persistent low bone mineral density is an independent prognostic factor for curve progression. The fundamental question of how bone quality is affected in AIS remains controversy because there is lack of site-matched control for detailed analysis on bone-related parameters. In this case-control study, trabecular bone biopsies from iliac crest were collected intra-operatively from 28 severe AIS patients and 10 matched controls with similar skeletal and sexual maturity, anthropometry and femoral neck BMD Z-score to control confounding effects. In addition to static histomorphometry, micro-computed tomography (μCT) and real time-PCR (qPCR) analyses, individual trabecula segmentation (ITS)-based analysis, finite element analysis (FEA), energy dispersive X-ray spectroscopy (EDX) were conducted to provide advanced analysis of structural, mechanical and mineralization features. μCT and histomorphometry showed consistently reduced trabecular number and connectivity. ITS revealed predominant change in trabecular rods, and EDX confirmed less mineralization. The structural and mineralization abnormality led to slight reduction in apparent modulus, which could be attributed to differential down-regulation of Runx2, and up-regulation of Spp1 and TRAP. In conclusion, this is the first comprehensive study providing direct evidence of undefined unique pathological changes at different bone hierarchical levels in AIS
Deep Neural Network Discrimination of Multiplexed Superconducting Qubit States
Demonstrating a quantum computational advantage will require high-fidelity
control and readout of multi-qubit systems. As system size increases,
multiplexed qubit readout becomes a practical necessity to limit the growth of
resource overhead. Many contemporary qubit-state discriminators presume
single-qubit operating conditions or require considerable computational effort,
limiting their potential extensibility. Here, we present multi-qubit readout
using neural networks as state discriminators. We compare our approach to
contemporary methods employed on a quantum device with five superconducting
qubits and frequency-multiplexed readout. We find that fully-connected
feedforward neural networks increase the qubit-state-assignment fidelity for
our system. Relative to contemporary discriminators, the assignment error rate
is reduced by up to 25% due to the compensation of system-dependent
nonidealities such as readout crosstalk which is reduced by up to one order of
magnitude. Our work demonstrates a potentially extensible building block for
high-fidelity readout relevant to both near-term devices and future
fault-tolerant systems.Comment: 18 Pages, 9 figure
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