2,393 research outputs found
The swap operation in the two-qubit Heisenberg XXZ model-effects of anisotropy and magnetic field
In this paper we study the swap operation in a two-qubit anisotropic XXZ
model in the presence of an inhomogeneous magnetic field. We establish the
range of anisotropic parameter within which the swap operation is feasible. The
swap errors caused by the inhomogeneous field are evaluated
Ultraquantum magnetoresistance in Kramers Weyl semimetal candidate -Ag2Se
The topological semimetal -Ag2Se features a Kramers Weyl node at the
origin in momentum space and a quadruplet of spinless Weyl nodes, which are
annihilated by spin-orbit coupling. We show that single crystalline
-Ag2Se manifests giant Shubnikov-de Haas oscillations in the
longitudinal magnetoresistance which stem from a small electron pocket that can
be driven beyond the quantum limit by a field less than 9 T. This small
electron pocket is a remainder of the spin-orbit annihilatedWeyl nodes and thus
encloses a Berry-phase structure. Moreover, we observed a negative longitudinal
magnetoresistance when the magnetic field is beyond the quantum limit. Our
experimental findings are complemented by thorough theoretical band structure
analyses of this Kramers Weyl semimetal candidate, including first-principle
calculations and an effective k*p model.Comment: A new version based on arXiv:1502.0232
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The sibling effect on neurodevelopment of preschoolers under China’s newly relaxed child policy: a national retrospective cohort study
Introduction: The change in Chinese fertility policy brings new challenges and considerations for children’s health outcomes; however, very little is known about the interaction between siblings, family socioeconomic status (SES), and neurodevelopment in the Chinese preschool-age population. Therefore, this study aimed to develop a new explanatory pathway from sibling effect to early childhood development and explored the mediation effect of family SES in the pathway.
Methods: From April 2018 to December 2019, we conducted a national retrospective cohort study in 551 cities in China, and a total of 115,915 preschool-aged children were selected for the final analysis. Children’s neurodevelopment, including Communication, Gross motor, Fine motor, Problem-solving, and Personal-social, was assessed with the Ages & Stages Questionnaires, Third Edition (ASQ-3). Hypothesis tests and multilevel regression models were used to assess the associations and their strength between sibling effect and neurodevelopmental delay. Pathway analysis was used to verify the mediation effect of SES.
Results: The results showed that there were significant risk effects of a sibling on preschoolers’ overall neurodevelopment including communication, gross motor, fine motor, and problem-solving delay. The adjustment of family SES, however, brought a reversal of this association. The results of the mediation model illustrated a direct, protective effect of one-sibling status (βASQ-delay = −0.09; βASQ-scores = 0.07; p < 0.001), and an indirect, risk effect from one-sibling status through family SES to neurodevelopment outcomes (βASQ-delay =0.12; βASQ-scores = −0.12; p < 0.001). The total sibling effect was weakened but remained negative (βASQ-delay =0.03; βASQ-scores = −0.05; p < 0.001).
Discussion: This study concluded that family SES mediated the negative effects of one sibling on early child development. To enhance the positive influence of sibling addition, we suggested providing more resources and instructions to the families with less educated and poorer employed parents under the coming multi-child era
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Differentiating the cognitive development of early-term births in infants and toddlers: a cross-sectional study in China
Objectives:
This study aimed to explore the cognitive development of low-risk children during early childhood for early-term births at 37 and 38 weeks of gestation compared with full term births at 39–41 weeks of gestation.
Setting and participants:
We conducted a cross-sectional study in Shanghai, one of the largest cities in China. A total of 1444 children from singleton pregnancies born at term gestation were included in the study.
Measures:
The cognitive outcomes of the subjects were measured using the cognitive subtest of Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) across three cities in China. We analysed the association between gestational age and cognitive development during infancy and toddler stages using multivariate linear modelling.
Results:
The cognitive development scores for infants born at 37 gestational weeks were significantly lower than those born at 39–41 gestational weeks (β=−2.257, 95%CI −4.280 to −0.235; p0.05). Moreover, these effects were not found in toddlers (between 17 and 48 months of age) after adjusting for the possible confounders (p>0.05).
Conclusions:
Infants born at 37 weeks of gestation exhibited weaker cognitive ability compared with those born at 39–41 weeks of gestation. Our findings provide evidences for the close monitoring of potential developmental problems in early-term children, especially those born at 37 gestational weeks
The effects of degree correlations on network topologies and robustness
Complex networks have been applied to model numerous interactive nonlinear
systems in the real world. Knowledge about network topology is crucial for
understanding the function, performance and evolution of complex systems. In
the last few years, many network metrics and models have been proposed to
illuminate the network topology, dynamics and evolution. Since these network
metrics and models derive from a wide range of studies, a systematic study is
required to investigate the correlations between them. The present paper
explores the effect of degree correlation on the other network metrics through
studying an ensemble of graphs where the degree sequence (set of degrees) is
fixed. We show that to some extent, the characteristic path length, clustering
coefficient, modular extent and robustness of networks are directly influenced
by the degree correlation.Comment: 13 pages, 6 figure
Angular Dependences of Third Harmonic Generation from Microdroplets
We present experimental and theoretical results for the angular dependence of
third harmonic generation (THG) of water droplets in the micrometer range (size
parameter ). The THG signal in - and -polarization obtained
with ultrashort laser pulses is compared with a recently developed nonlinear
extension of classical Mie theory including multipoles of order .
Both theory and experiment yield over a wide range of size parameters
remarkably stable intensity maxima close to the forward and backward direction
at ``magic angles''. In contrast to linear Mie scattering, both are of
comparable intensity.Comment: 4 pages, RevTeX, 3 figures available on request from
[email protected], submitted to PR
Krüppel-Like Factor 8 Is a New Wnt/Beta-Catenin Signaling Target Gene and Regulator in Hepatocellular Carcinoma
Krüppel-like factor 8 (KLF8) plays important role in cell cycle and oncogenic transformation. Here we report the mechanisms by which KLF8 crosstalks with Wnt/β-catenin signaling pathway and regulates hepatocellular carcinoma (HCC) cells proliferation. We show that overexpression of KLF8 and nucleus accumulation of β-catenin in the human HCC samples are positively correlated. More importantly, KLF8 protein levels plus nucleus accumulation of β-catenin levels were significantly elevated in high-grade HCC compared to low-grade HCC. Using HCC HepG2 cells we find that, on the one hand both protein and mRNA of KLF8 are up-regulated under Wnt3a stimulation, on the other hand overexpression of KLF8 increases the cytoplasm and nucleus accumulation of β-catenin, recruits p300 to β-catenin/T-cell factor 4 (TCF4) transcription complex, enhances TOP flash report gene transcription, and induces Wnt/β-catenin signaling target genes c-Myc, cyclin D1 and Axin1 expression. Knockdown of KLF8 using shRNA inhibits Wnt3a induced transcription of TOP flash report gene and expression of c-Myc, cyclin D1 and Axin1. Knockdown of β-catenin by shRNA rescues the enhanced HepG2 and Hep3B cells proliferation ability induced by overexpression of KLF8
Self-guiding of 100 TW Femtosecond Laser Pulses in Centimeter-scale Underdense Plasma
An experiment for studying laser self-guiding has been carried out for the
high power ultrashort pulse laser interaction with an underdense plasma slab.
Formation of an extremely long plasma channel and its bending are observed when
the laser pulse power is much higher than the critical power for relativistic
self-focusing. The long self-guiding channel formation is accompanied by
electron acceleration with a low transverse emittance and high electric
current. Particle-in-cell simulations show that laser bending occurs when the
accelerated electrons overtake the laser pulse and modify the refractive index
in the region in front of the laser pulse
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