Evaluating the impact of highway construction projects on landscape ecological risks in high altitude plateaus

[EN] In China and other countries, many highway projects are built in extensive and high-altitude flat areas called plateaus. However, research on how the materialisation of these projects produce a series of ecological risks in the landscape is very limited. In this research, a landscape ecological risk analysis model for high-altitude plateaus is proposed. This model is based on the pattern of land uses of the surrounding area. Our study includes buffer analysis, spatial analysis, and geostatistical analysis. We apply the model to the Qumei to Gangba highway, a highway section located in the southeast city of Shigatse at the Chinese Tibet autonomous region. Through global and local spatial autocorrelation analysis, the spatial clustering distribution of ecological risks is also explored. Overall, our study reveals the spatial heterogeneity of ecological risks and how to better mitigate them. According to a comparison of the risk changes in two stages (before and after the highway construction), the impact of highway construction on the ecological environment can be comprehensively quantified. This research will be of interest to construction practitioners seeking to minimize the impact of highway construction projects on the ecological environment. It will also inform future empirical studies in the area of environmental engineering with potential affection to the landscape in high-altitude plateaus.This research is supported by the Branch of China Road and Bridge Corporation (Cambodia) Technology Development Project (No.2020-zlkj-04); National Social Science Fund Projects (No.20BJY010); National Social Science Fund Post-financing Projects (No.19FJYB017); Sichuan-Tibet Railway Major Fundamental Science Problems Special Fund (No.71942006); Qinghai Natural Science Foundation (No. 2020-JY-736); List of Key Science and Technology Projects in China's Transportation Industry in 2018-International Science and Technology Cooperation Project (Nos. 2018-GH-006 and 2019-MS5-100); Emerging Engineering Education Research and Practice Project of Ministry of Education of China (No. E-GKRWJC20202914); Shaanxi Social Science Fund (No. 2017S004); Xi'an Construction Science and Technology Planning Project (Nos. SZJJ201915 and SZJJ201916); Shaanxi Province Higher Education Teaching Reform Project (No. 19BZ016); Fundamental Research for Funds for the Central Universities (Humanities and Social Sciences), Chang'an University (Nos. 300102239616, 300102281669 and 300102231641).Li, C.; Zhang, J.; Philbin, SP.; Yang, X.; Dong, Z.; Hong, J.; Ballesteros-Pérez, P. (2022). Evaluating the impact of highway construction projects on landscape ecological risks in high altitude plateaus. Scientific Reports. 12(1):1-16. https://doi.org/10.1038/s41598-022-08788-811612

Direct CP violation of B→lνB \to l \nu in unparticle physics

We have investigated the effects of unparticles in decays $B \to l \nu$. It is found that the direct CP violation in the decays, which is zero in SM, can show up due to the CP conserving phase intrinsic in unparticle physics. For $l=\tau$, the direct CP asymmetry can reach 30% for the scalar unparticle contribution, and 100% for the longitudinal vector unparticle contribution under the constraints of ${\rm Br}(B\to\tau\nu)$ and $\nu e$ elastic scattering. If both unparticle-lepton coupling universality and unparticle-quark coupling universality are assumed the constraint from $Br(\pi\to \mu\nu)$ leads that the direct CP violation in $B\to l\nu$ can only reach at most 8% and 1% for scalar and vector unparticle contributions respectively if $d_{\cal U} < 2$. If the direct CP violation is observed in the future it would give strong evidence for the existence of unparticle stuff.Comment: 9 pages, 2 figures, to appear in PR

Probing flavor changing interactions in hadron collisions

The subprocess $gg \to t\bar{c}+\bar{t}c$ in the two-Higgs-doublet model with flavor-changing scalar couplings is examined at the one loop level. With perturbative QCD factorization theorem, the corresponding cross sections for hadron-hadron collisions are computed numerically. The results are applicable to the whole mass range of the weakly coupled Higgs bosons. In case we could efficiently exclude the severe backgrounds of the $t\bar{c}(\bar{t}c)$ production signal, probing the flavor-changing top-charm-scalar vertex at hadron colliders would be very promising and accessible experimentally.Comment: LaTex file, 14 pages, 8 EPS figure

From the Complete Yang Model to Snyder's Model, de Sitter Special Relativity and Their Duality

By means of Dirac procedure, we re-examine Yang's quantized space-time model, its relation to Snyder's model, the de Sitter special relativity and their UV-IR duality. Starting from a dimensionless dS_5-space in a 5+1-d Mink-space a complete Yang model at both classical and quantum level can be presented and there really exist Snyder's model, the dS special relativity and the duality.Comment: 7 papge

Properties of Light Flavour Baryons in Hypercentral quark model

The light flavour baryons are studied within the quark model using the hyper central description of the three-body system. The confinement potential is assumed as hypercentral coulomb plus power potential ($hCPP_\nu$) with power index $\nu$. The masses and magnetic moments of light flavour baryons are computed for different power index, $\nu$ starting from 0.5 to 1.5. The predicted masses and magnetic moments are found to attain a saturated value with respect to variation in $\nu$ beyond the power index $\nu>$ 1.0. Further we computed transition magnetic moments and radiative decay width of light flavour baryons. The results are in good agreement with known experimental as well as other theoretical models.Comment: Accepted in Pramana J. of Physic

Robust estimation of microbial diversity in theory and in practice

Quantifying diversity is of central importance for the study of structure, function and evolution of microbial communities. The estimation of microbial diversity has received renewed attention with the advent of large-scale metagenomic studies. Here, we consider what the diversity observed in a sample tells us about the diversity of the community being sampled. First, we argue that one cannot reliably estimate the absolute and relative number of microbial species present in a community without making unsupported assumptions about species abundance distributions. The reason for this is that sample data do not contain information about the number of rare species in the tail of species abundance distributions. We illustrate the difficulty in comparing species richness estimates by applying Chao's estimator of species richness to a set of in silico communities: they are ranked incorrectly in the presence of large numbers of rare species. Next, we extend our analysis to a general family of diversity metrics ("Hill diversities"), and construct lower and upper estimates of diversity values consistent with the sample data. The theory generalizes Chao's estimator, which we retrieve as the lower estimate of species richness. We show that Shannon and Simpson diversity can be robustly estimated for the in silico communities. We analyze nine metagenomic data sets from a wide range of environments, and show that our findings are relevant for empirically-sampled communities. Hence, we recommend the use of Shannon and Simpson diversity rather than species richness in efforts to quantify and compare microbial diversity.Comment: To be published in The ISME Journal. Main text: 16 pages, 5 figures. Supplement: 16 pages, 4 figure

Multi-ion Mach-Zehnder interferometer with artificial nonlinear interactions

We show how to implement a Mach-Zehnder interferometry based upon a string of trapped ions with artificial nonlinear interactions. By adiabatically sweeping down/up the coupling strength between two involved internal states of the ions, we could achieve the beam splitting/recombination. Based on current techniques for manipulating trapped ions, we discuss the experimental feasibility of our scheme and analyze some undesired uncertainty under realistic experimental environment.Comment: 6 pages, 3 figure

Novel CP-violating Effects in B decays from Charged-Higgs in a Two-Higgs Doublet Model for the Top Quark

We explore charged-Higgs cp-violating effects in a specific type III two-Higgs doublet model which is theoretically attractive as it accommodates the large mass of the top quark in a natural fashion. Two new CP-violating phases arise from the right-handed up quark sector. We consider CP violation in both neutral and charged B decays. Some of the important findings are as follows. 1) Large direct-CP asymmetry is found to be possible for B+- to psi/J K+-. 2) Sizable D-anti-D mixing effect at the percent level is found to be admissible despite the stringent constraints from the data on K-anti-K mixing, b to s gamma and B to tau nu decays. 3) A simple but distinctive CP asymmetry pattern emerges in decays of B_d and B_s mesons, including B_d to psi/J K_S, D+ D-, and B_s to D_s+ D_s-, psi eta/eta^prime, psi/J K_S. 4) The effect of D-anti-D mixing on the CP asymmetry in B+- to D/anti-D K+- and on the extraction of the angle gamma of the unitarity triangle from such decays can be significant.Comment: 32 pages, 5 figures, section V.A revised, version to appear in PR

On-demand semiconductor single-photon source with near-unity indistinguishability

Single photon sources based on semiconductor quantum dots offer distinct advantages for quantum information, including a scalable solid-state platform, ultrabrightness, and interconnectivity with matter qubits. A key prerequisite for their use in optical quantum computing and solid-state networks is a high level of efficiency and indistinguishability. Pulsed resonance fluorescence (RF) has been anticipated as the optimum condition for the deterministic generation of high-quality photons with vanishing effects of dephasing. Here, we generate pulsed RF single photons on demand from a single, microcavity-embedded quantum dot under s-shell excitation with 3-ps laser pulses. The pi-pulse excited RF photons have less than 0.3% background contributions and a vanishing two-photon emission probability. Non-postselective Hong-Ou-Mandel interference between two successively emitted photons is observed with a visibility of 0.97(2), comparable to trapped atoms and ions. Two single photons are further used to implement a high-fidelity quantum controlled-NOT gate.Comment: 11 pages, 11 figure