Preen Gland-Secreted Alkanols Enhance Male Attractiveness in Parrots

The skin glands are widely used in pheromone production throughout the vertebrate worlds. Growing evidences show that birds also have chemical communication, but the uropygial (also called preen or oil) glands, serving as only specialized skin glands of birds, have no sex pheromones characterized. Here, by combining GC-MS analysis and bioassay, we show with the budgerigar, Melopsittacus undulatus, that birds can used the preen gland-secreted volatiles (a blend of octadecanol, nonadecanol and eicosanol for male budgerigars) spread over body plumage when preening to convey sex information. Here, we first report the avian pheromones derived from the uropyginal gland and suggests that the gland has broader implications than previously known (e.g. plumage waterproofing and reflectance in sexual behaviour of birds

Competing orders and inter-layer tunnelling in cuprate superconductors: A finite temperature Landau theory

We propose a finite temperature Landau theory that describes competing orders and interlayer tunneling in cuprate superconductors as an important extension to a corresponding theory at zero temperature [Nature {\bf 428}, 53 (2004)], where the superconducting transition temperature $T_c$ is defined in three possible ways as a function of the zero temperature order parameter. For given parameters, our theory determines $T_c$ without any ambiguity. In mono- and double-layer systems we discuss the relation between zero temperature order parameter and the associated transition temperature in the presence of competing orders, and draw a connection to the puzzling experimental fact that the pseudo-gap temperature is much higher than the corresponding energy scale near optimum doping. Applying the theory to multi-layer systems, we calculate the layer-number dependence of $T_c$. In a reasonable parameter space the result turns out to be in agreement with experiments.Comment: 5 pages, 3 figure

Comparison of 2.2mm micro incision and 3.0mm incision coaxial phacoemulsification

AIM:To compare the operation effect of 2.2mm micro incision and 3.0mm incision coaxial phacoemulsification.<p>METHODS: Patients with age-related cataract(90 cases, 90 eyes)were enrolled in the study from January 2012 to June 2013 in our hospital, and they were randomly divided into 2 groups: 2.2mm incision group(45 eyes of 45 cases), 3.0mm incision group(45 eyes of 45 cases). Corneal tunnel incision coaxial phacoemulsification was performed. At 1d, 1wk, 1, 3mo after operation, the visual acuity, corneal endothelial cell count, central corneal thickness, operation astigmatism were recorded.<p>RESULTS: One day after operation, the visual acuity of 2.2mm incision group were significantly improved, the difference was statistically significant(<i>P</i><0.05), there were no differences in two groups at 1wk, 1, 3mo after operation. No significant differences between the two groups of corneal endothelial cell counting, central corneal thickness at 1wk, 1, 3mo after operation were observed(<i>P</i>>0.05). Operation source astigmatism had statistically significant difference at 1d, 1wk, 1, 3mo after operation(<i>P</i><0.05), it decreased significantly in the 2.2mm incision group. <p>CONCLUSION: The 2.2mm small incision coaxial phacoemulsification with postoperative visual acuity improved more significantly, can significantly reduce the operation astigmatism

Pure Spin Photocurrent in Non-centrosymmetric Crystals: Bulk Spin Photovoltaic Effect

Spin current generators are critical components for spintronics-based information processing. In this work, we theoretically and computationally investigate the bulk spin photovoltaic (BSPV) effect for creating DC spin current under light illumination. The only requirement for BPSV is inversion symmetry breaking, thus it applies to a broad range of materials and can be readily integrated with existing semiconductor technologies. The BSPV effect is a cousin of the bulk photovoltaic (BPV) effect, whereby a DC charge current is generated under light. Thanks to the different selection rules on spin and charge currents, a pure spin current can be realized if the system possesses mirror symmetry or inversion-mirror symmetry. The mechanism of BPSV and the role of the electronic relaxation time $\tau$ are also elucidated. We apply our theory to several distinct material systems, including transition metal dichalcogenides, anti-ferromagnetic $\rm MnBi_2Te_4$, and the surface of topological crystalline insulator cubic $\rm SnTe$.Comment: 21 pages, 4 figure