ALBERT

Description: Author(s): N. Xu, T. Qian, P. Richard, Y.-B. Shi, X.-P. Wang, P. Zhang, Y.-B. Huang, Y.-M. Xu, H. Miao, G. Xu, G.-F. Xuan, W.-H. Jiao, Z.-A. Xu, G.-H. Cao, and H. Ding We report a systematic angle-resolved photoemission spectroscopy study on Ba(Fe 1− x Ru x ) 2 As 2 for a wide range of Ru concentrations (0.15⩽ x ⩽0.74). We observed a crossover from two dimensions to three dimensions for some of the holelike Fermi surfaces with Ru substitution and a large reduction in the ma... [Phys. Rev. B 86, 064505] Published Fri Aug 03, 2012

Description: Author(s): Z.-H. Liu, P. Richard, N. Xu, G. Xu, Y. Li, X.-C. Fang, L.-L. Jia, G.-F. Chen, D.-M. Wang, J.-B. He, T. Qian, J.-P. Hu, H. Ding, and S.-C. Wang We report a comprehensive angle-resolved photoemission spectroscopy study of the tridimensional electronic bands in the recently discovered Fe selenide superconductor (Tl,Rb) y Fe 2-x Se 2 ( T c =32  K ). We determined the orbital characters and the k z dependence of the low energy electronic structure by tun... [Phys. Rev. Lett. 109, 037003] Published Fri Jul 20, 2012

Description: Solar radiation pressure acting on a planet's surface is traditionally considered as a sun's mass correction to the Keplerian motion. For a solar-orbit satellite, because the area to mass ratio varies due to the orientation uncertainty of the solar panel, the orbital disturbance should be considered using disturbing theory. An analytic solution of a solar-satellite orbit disturbed by the solar radiation pressure is derived. The mean anomaly M is subjected to a secular perturbation, and there exist short-periodic disturbances on all Keplerian elements. By comparing the results with that of the sun's mass correction, we found out that the result obtained by traditional sun's mass correction implicitly uses a focus, which is the common mass centre of the sun and the correcting mass and which rotates along with the satellite related to the solar mass centre, as a reference of the orbital ellipse. The focus is also not an inertial reference point.

Description: In this work, a composite electrode was fabricated by chemical deposition of polydopamine (PDA) and graphene oxide (GO) on the copper foam (CF) surface, followed by annealing treatment. Owing to the cohesive effect of the PDA middle film, GO was coated on CF surface successfully, and then reduced simultaneously while annealing. The resulted rGO/PDA/CF composite electrode was directly used as a supercapacitor electrode and exhibited excellent electrochemical performance, with a high specific capacitance of 1250 F g -1 at 2 A g -1 and favorable cycle stability.

Description: Small differences in the sensitivity of stomatal conductance to light intensity on leaf surfaces may lead to large differences in total canopy transpiration ( E C ) with increasing canopy leaf area ( L ). Typically, the increase of L would more than compensate for the decrease of transpiration per unit of leaf area ( E L ), resulting in concurrent increase of E C . However, highly shade-intolerant species, such as Larix principis-rupprechtii Mayr., may be so sensitive to increased shading that such compensation is not complete. We hypothesized that in such a stand, windfall-induced spatial variation at a decameter scale would result in greatly reduced E L in patches of high L leading to lower E C than low competition patches of sparse canopy. We further hypothesized that quicker extraction of soil moisture in patches of lower competition will result in earlier onset of drought symptoms in these patches. Thus, patches of low L will transition from light to soil moisture as the factor dominating E L . This process should progressively homogenize E C in the stand even as the variation of soil moisture is increasing. We tested the hypotheses utilizing sap flux of nine trees, and associated environmental and stand variables. The results were consistent with only some of the expectations. Under non-limiting soil moisture, E L was very sensitive to the spatial variation of L , decreasing sharply with increasing L and associated decrease of mean light intensity on leaf surfaces. Thus, under the conditions of ample soil moisture maximum E C decreased with increasing patch-scale L . Annual E C and biomass production also decreased with L , albeit more weakly. Furthermore, variation of E C among patches decreased as average stand soil moisture declined between rain events. However, contrary to expectation, high L plots which transpired less showed a greater E L sensitivity to decreasing stand-scale soil moisture, suggesting a different mechanism than simple control by decreasing soil moisture. We offer potential explanations to the observed phenomenon. Our results demonstrate that spatial variation of L at decameter scale, even within relatively homogeneous, single-species, even-aged stands, can produce large variation of transpiration, soil moisture and biomass production and should be considered in 1-D soil–plant–atmosphere models.

Description: Genome-wide association studies (GWAS) have identified several common loci contributing to non-obstructive azoospermia (NOA). However, a substantial fraction of NOA heritability remains undefined, especially those low-frequency [defined here as having a minor allele frequency (MAF) between 0.5 and 5%] and rare (MAF below 0.5%) variants. Here, we performed a 3-stage exome-wide association study in Han Chinese men to evaluate the role of low-frequency or rare germline variants in NOA development. The discovery stage included 962 NOA cases and 1348 healthy male controls genotyped by exome chips and was followed by a 2-stage replication with an additional 2168 cases and 5248 controls. We identified three low-frequency variants located at 6p22.2 (rs2298090 in HIST1H1E encoding p.Lys152Arg: OR = 0.30, P = 2.40 x 10 –16 ) and 6p21.33 (rs200847762 in FKBPL encoding p.Pro137Leu: OR = 0.11, P = 3.77 x 10 –16 ; rs11754464 in MSH5 : OR = 1.78, P = 3.71 x 10 –7 ) associated with NOA risk after Bonferroni correction. In summary, we report an instance of newly identified signals for NOA risk in genes previously undetected through GWAS on 6p22.2–6p21.33 in a Chinese population and highlight the role of low-frequency variants with a large effect in the process of spermatogenesis.

Description: Author(s): G. Xu, J. Garnier, A. Mussot, S. Trillo, D. Churkin, N. Tarasov, S. Turitsyn, and A. Picozzi We study theoretically and numerically the dynamics of a passive optical fiber ring cavity pumped by a highly incoherent wave: an incoherently injected fiber laser. The theoretical analysis reveals that the turbulent dynamics of the cavity is dominated by the Raman effect. The forced-dissipative nat… [Phys. Rev. A 94, 013823] Published Tue Jul 12, 2016

Description: Weyl semimetals are of great interest because they provide the first realization of the Weyl fermion, exhibit exotic quantum anomalies, and host Fermi arc surface states. The separation between Weyl nodes of opposite chirality gives a measure of the robustness of the Weyl semimetal state. To exploit the novel phenomena that arise from Weyl fermions in applications, it is crucially important to find robust separated Weyl nodes. We propose a methodology to design robust Weyl semimetals with well-separated Weyl nodes. Using this methodology as a guideline, we search among the material parameter space and identify by far the most robust and ideal Weyl semimetal candidate in the single-crystalline compound tantalum sulfide (Ta 3 S 2 ) with new and novel properties beyond TaAs. Crucially, our results show that Ta 3 S 2 has the largest k -space separation between Weyl nodes among known Weyl semimetal candidates, which is about twice larger than the measured value in TaAs and 20 times larger than the predicted value in WTe 2 . Moreover, all Weyl nodes in Ta 3 S 2 are of type II. Therefore, Ta 3 S 2 is a type II Weyl semimetal. Furthermore, we predict that increasing the lattice by 〈4% can annihilate all Weyl nodes, driving a novel topological metal-to-insulator transition from a Weyl semimetal state to a topological insulator state. The robust type II Weyl semimetal state and the topological metal-to-insulator transition in Ta 3 S 2 are potentially useful in device applications. Our methodology can be generally applied to search for new Weyl semimetals.

Description: Aims Understanding relationships between vegetation and environments is of importance for ecosystem restoration and management. However, information on how environments influence the floristic patterns of shrublands is lack, especially in the subtropical China. In this study, we explored how environments regulate species composition of shrublands at landscape scale in mid-subtropical China. Methods We investigated species composition and measured the climate and soil environments for 207 shrubland plots in mid-subtropical China (24°39'–30°08'N, 108°47'–114°15'E). We applied a hierarchical cluster analysis and indicator species analysis based on the Bray–Curtis similarity index to identify the main shrubland types and employed principal coordinate analysis (PCoA) to explore the relationship between floristic composition and environment. Important Findings We identified four shrubland types occurring in different environmental conditions. Montane shrubland, dominated by species suitable for cool climates (e.g. Rhododendron simsii ), were distributed in steep areas at comparatively high altitudes; foothill shrubland, dominated by mesophilous species (e.g. Loropetalum chinense ), were distributed in low mountains and hills; pioneer shrubland, dominated by fast grow and short-life cycles species (e.g. Rhus chinensis ), were distributed at low altitudes with dense population; and finally, limestone shrubland, dominated by calcicole plants (e.g. Coriaria nepalensis ), were distributed in the extensive karst areas. Communities occurring in high pH soils were completely separated from those in low pH soils according to the hierarchical cluster analysis. PCoA ordination associated the four types with distinct edaphic and climatic gradients. Soil pH explained 63.3% of variation in PCoA, followed by soil depth and soil bulk density.