258 research outputs found

    Planimetría de alta resolución del dolmen de Menga (Antequera, Málaga) mediante escaneado láser terrestre, levantamiento 3D y fotogrametría

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    Dielectric metasurfaces can achieve flexible beam manipulations. Herein, we study dielectric metasurfaces with different refractive indices, periods, incident angles, and cross-sectional shapes to determine the metasurface working mechanisms. Perfect transmission mainly depends on multipolar interference that can be used to control the transmission modes through the hybrid periods, hybrid cross sections, and multilayers. Perfect reflection is strongly influenced by the period of the metasurface and occurs only when the period is shorter than incident wavelength, which can be attributed to the lattice coupling. Furthermore, lattice coupling can be classified into two types with distinct properties: vertical mode and horizontal mode coupling. The vertical mode appears when the effective wavelength matches the feature size, whereas the horizontal mode only appears when the incident wavelength is close to the period. The horizontal mode is sensitive to the incident angle. The revealed functioning mechanisms enable further practical applications of metasurfaces

    Topological Atomic Spinwave Lattices by Dissipative Couplings

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    Recent experimental advance in creating dissipative couplings provides a new route for engineering exotic lattice systems and exploring topological dissipation. Using the spatial lattice of atomic spinwaves in a vacuum vapor cell, where purely dissipative couplings arise from diffusion of atoms, we experimentally realize a dissipative version of the Su-Schrieffer-Heeger (SSH) model. We construct the dissipation spectra of the topological or trivial lattices via electromagnetically-induced-transparency (EIT) spectroscopy. The topological dissipation spectrum is found to exhibit edge modes at dissipation rates within a dissipative gap, decoupled from the bulk. We also validate chiral symmetry of the dissipative SSH couplings. This work paves the way for realizing topology-enabled quantum correlations and non-Hermitian topological quantum optics via dissipative couplings.Comment: 5 pages, 4 figure

    Beam Manipulation Mechanisms of Dielectric Metasurfaces

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    Dielectric metasurfaces can achieve flexible beam manipulations. Herein, we study dielectric metasurfaces with different refractive indices, periods, incident angles, and cross-sectional shapes to determine the metasurface working mechanisms. Perfect transmission mainly depends on multipolar interference that can be used to control the transmission modes through the hybrid periods, hybrid cross sections, and multilayers. Perfect reflection is strongly influenced by the period of the metasurface and occurs only when the period is shorter than incident wavelength, which can be attributed to the lattice coupling. Furthermore, lattice coupling can be classified into two types with distinct properties: vertical mode and horizontal mode coupling. The vertical mode appears when the effective wavelength matches the feature size, whereas the horizontal mode only appears when the incident wavelength is close to the period. The horizontal mode is sensitive to the incident angle. The revealed functioning mechanisms enable further practical applications of metasurfaces

    The efficacy of dapagliflozin for type 1 diabetes: a meta-analysis of randomized controlled studies

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    Introduction: The efficacy of dapagliflozin for type 1 diabetes remains controversial. We conduct a systematic review and meta-analysis to explore the treatment efficacy of dapagliflozin versus placebo in patients with type 1 diabetes. Methods: We have searched PubMed, EMbase, Web of science, EBSCO and Cochrane library databases through May 2019 for randomized controlled trials (RCTs) assessing the effect of dapagliflozin versus placebo for type 1 diabetes. This meta-analysis is performed using the random-effect model. Results: Six RCTs are included in the meta-analysis. Overall, compared with control group for type 1 diabetes, dapagliflozin treatment shows favorable impact on glycated hemoglobin HbA1c ( standard mean difference SMD=-3.93; 95% confidence interval CI =-4.44 to -3.48; P<0.00001), HbA1c reduction of 650.5% (risk ratio RR=1.98; 95% CI=1.65 to 2.39; P<0.00001), and fasting plasma glucose FPG (SMD=-0.93; 95% CI=-1.77 to -0.10; P=0.03). There is no statistical difference of hypoglycemia (RR=1.09; 95% CI=0.66 to 1.79; P=0.75) or adverse events (RR=1.07; 95% CI=0.96 to 1.20; P=0.20) between two groups, but the incidence of ketone-related events is higher than those in control group (RR=0.28; 95% CI=3.96 to 11.52; P=0.01). Conclusions: Dapagliflozin treatment benefits to reduce HbA1c and FPG for type 1 diabetes

    Genetic Variants on Chromosome 8q24 and Colorectal Neoplasia Risk: A Case-Control Study in China and a Meta-Analysis of the Published Literature

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    Previous studies have found that common genetic variants on chromosome 8q24 are associated with the risk of developing colorectal neoplasia. We conducted a hospital-based case-control study, including 435 cases and 788 unrelated controls to investigate the associations between common variants on 8q24 and the risk of colorectal cancer in a Chinese population. We also evaluated the association of rs6983267 with colorectal neoplasia in the published literature via a meta-analysis study. We found that rs6983267 was significantly associated with the risk of colorectal cancer in the Chinese population, with an adjusted odds-ratio (OR) for the GT heterozygotes and GG homozygotes of 1.30 (95% CI  = 0.98–1.71, P = 0.069) and 1.66 (95% CI  = 1.18–2.34, P = 0.004), respectively, compared to the TT homozygotes, with a P-trend value of 0.003. No association was found for the other three loci (rs16901979, rs1447295 and rs7837688). In the meta-analysis of the published genetic association studies, the rs6983267 variant was found to be associated with an increased risk of colorectal neoplasia. The heterozygous GT carriers showed a 20% increased risk of colorectal neoplasia (OR  = 1.20, 95% CI  = 1.16–1.25; random effects model) with a summary OR for homozygous GG carriers of 1.39 (95% CI  = 1.32–1.48; random effects model) compared to the TT genotype carriers. We found no significant differences between the association of rs6983267 and colorectal cancer and colorectal adenomas. In summary, our study confirms that the variant rs6983267 is a risk factor for colorectal neoplasia in various populations, including the Chinese population
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