Magnetic anisotropy and spin-spiral wave in V, Cr and Mn atomic chains on Cu(001) surface: First principles calculations

Recent ab intio studies of the magnetic properties of all 3d transition metal(TM) freestanding atomic chains predicted that these nanowires could have a giant magnetic anisotropy energy (MAE) and might support a spin-spiral structure, thereby suggesting that these nanowires would have technological applicationsin, e.g., high density magnetic data storages. In order to investigate how the substrates may affect the magnetic properties of the nanowires, here we systematically study the V, Cr and Mn linear atomic chains on the Cu(001) surface based on the density functional theory with the generalized gradient approximation. We find that V, Cr, and Mn linear chains on the Cu(001) surface still have a stable or metastable ferromagnetic state. However, the ferromagnetic state is unstable against formation of a noncollinear spin-spiral structure in the Mn linear chains and also the V linear chain on the atop sites on the Cu(001) surface, due to the frustrated magnetic interactions in these systems. Nonetheless, the presence of the Cu(001) substrate does destabilize the spin-spiral state already present in the freestanding V linear chain and stabilizes the ferromagnetic state in the V linear chain on the hollow sites on Cu(001). When spin-orbit coupling (SOC) is included, the spin magnetic moments remain almost unchanged, due to the weakness of SOC in 3d TM chains. Furthermore, both the orbital magnetic moments and MAEs for the V, Cr and Mn are small, in comparison with both the corresponding freestanding nanowires and also the Fe, Co and Ni linear chains on the Cu (001) surface.Comment: Accepted for publication in J. Phys. D: Applied Physic

Resonant Subband Landau Level Coupling in Symmetric Quantum Well

Subband structure and depolarization shifts in an ultra-high mobility GaAs/Al_{0.24}Ga_{0.76}As quantum well are studied using magneto-infrared spectroscopy via resonant subband Landau level coupling. Resonant couplings between the 1st and up to the 4th subbands are identified by well-separated anti-level-crossing split resonance, while the hy-lying subbands were identified by the cyclotron resonance linewidth broadening in the literature. In addition, a forbidden intersubband transition (1st to 3rd) has been observed. With the precise determination of the subband structure, we find that the depolarization shift can be well described by the semiclassical slab plasma model, and the possible origins for the forbidden transition are discussed.Comment: 4 pages, 2 figure

Genome-wide analysis points to roles for extracellular matrix remodeling, the visual cycle, and neuronal development in myopia

Myopia, or nearsightedness, is the most common eye disorder, resulting primarily from excess elongation of the eye. The etiology of myopia, although known to be complex, is poorly understood. Here we report the largest ever genome-wide association study (43,360 participants) on myopia in Europeans. We performed a survival analysis on age of myopia onset and identified 19 significant associations (p < 5e-8), two of which are replications of earlier associations with refractive error. These 19 associations in total explain 2.7% of the variance in myopia age of onset, and point towards a number of different mechanisms behind the development of myopia. One association is in the gene PRSS56, which has previously been linked to abnormally small eyes; one is in a gene that forms part of the extracellular matrix (LAMA2); two are in or near genes involved in the regeneration of 11-cis-retinal (RGR and RDH5); two are near genes known to be involved in the growth and guidance of retinal ganglion cells (ZIC2, SFRP1); and five are in or near genes involved in neuronal signaling or development. These novel findings point towards multiple genetic factors involved in the development of myopia and suggest that complex interactions between extracellular matrix remodeling, neuronal development, and visual signals from the retina may underlie the development of myopia in humans

Solar array stepping to minimize array excitation

Mechanical oscillations of a mechanism containing a stepper motor, such as a solar-array powered spacecraft, are reduced and minimized by the execution of step movements in pairs of steps, the period between steps being equal to one-half of the period of torsional oscillation of the mechanism. Each pair of steps is repeated at needed intervals to maintain desired continuous movement of the portion of elements to be moved, such as the solar array of a spacecraft. In order to account for uncertainty as well as slow change in the period of torsional oscillation, a command unit may be provided for varying the interval between steps in a pair

Suppression of both superconductivity and structural transition in hole-doped MoTe2_2 induced by Ta substitution

Type-II Weyl semimetal MoTe$_2$ exhibits a first-order structural transition at $T_s$ $\sim$250~K and superconducts at $T_c$ $\sim$0.1~K at ambient pressure. Both $T_s$ and $T_c$ can be manipulated by several tuning parameters, such as hydrostatic pressure and chemical substitution. It is often reported that suppressing $T_s$ enhances $T_c$, but our study shows a different behaviour when MoTe$_2$ is hole-doped by Ta. When $T_s$ is suppressed by Ta doping, $T_c$ is also suppressed. Our findings suggest that the suppression of $T_s$ does not necessarily enhance superconductivity in MoTe$_2$. By connecting with the findings of electron-doped MoTe$_2$, we argue that varying electron carrier concentration can effectively tune $T_c$. In addition, the Hall coefficient is enhanced around the doping region, where $T_s$ is completely suppressed, suggesting that the critical scattering around the structural transition may also play a role in suppressing $T_c$

Comment on "Reinterpreting aircraft measurement in anisotropic scaling turbulence" by Lovejoy et al. (2009)

Recently, Lovejoy et al. (2009) argued that the steep ~k−3 atmospheric kinetic energy spectrum at synoptic scales (≥1000 km) observed by aircraft is a spurious artefact of aircraft following isobars instead of isoheights. Without taking into account the earth's rotation they hypothesise that the horizontal atmospheric energy spectrum should scale as k−5/3 at all scales. We point out that the approximate k−3-spectrum at synoptic scales has been observed by a number of non-aircraft means since the 1960s and that general circulation models and other current models have successfully produced this spectrum. We also argue that the vertical movements of the aircraft are far too small to cause any strong effect on the measured spectrum at synoptic scales

Assessment of the genetic basis of rosacea by genome-wide association study.

Rosacea is a common, chronic skin disease that is currently incurable. Although environmental factors influence rosacea, the genetic basis of rosacea is not established. In this genome-wide association study, a discovery group of 22,952 individuals (2,618 rosacea cases and 20,334 controls) was analyzed, leading to identification of two significant single-nucleotide polymorphisms (SNPs) associated with rosacea, one of which replicated in a new group of 29,481 individuals (3,205 rosacea cases and 26,262 controls). The confirmed SNP, rs763035 (P=8.0 × 10(-11) discovery group; P=0.00031 replication group), is intergenic between HLA-DRA and BTNL2. Exploratory immunohistochemical analysis of HLA-DRA and BTNL2 expression in papulopustular rosacea lesions from six individuals, including one with the rs763035 variant, revealed staining in the perifollicular inflammatory infiltrate of rosacea for both proteins. In addition, three HLA alleles, all MHC class II proteins, were significantly associated with rosacea in the discovery group and confirmed in the replication group: HLA-DRB1*03:01 (P=1.0 × 10(-8) discovery group; P=4.4 × 10(-6) replication group), HLA-DQB1*02:01 (P=1.3 × 10(-8) discovery group; P=7.2 × 10(-6) replication group), and HLA-DQA1*05:01 (P=1.4 × 10(-8) discovery group; P=7.6 × 10(-6) replication group). Collectively, the gene variants identified in this study support the concept of a genetic component for rosacea, and provide candidate targets for future studies to better understand and treat rosacea

Bosonic t-J Model in a stacked triangular lattice and its phase diagram

In this paper, we study phase diagram of a system of two-component hard-core bosons with nearest-neighbor (NN) pseudo-spin antiferromagnetic (AF) interactions in a stacked triangular lattice. Hamiltonian of the system contains three parameters one of which is the hopping amplitude $t$ between NN sites, and the other two are the NN pseudo-spin exchange interaction $J$ and the one that measures anisotropy of pseudo-spin interactions. We investigate the system by means of the Monte-Carlo simulations and clarify the low-temperature phase diagram. In particular, we are interested in how the competing orders, i.e., AF order and superfluidity, are realized, and also whether supersolid forms as a result of hole doping into the state of the $\sqrt{3}\times \sqrt{3}$ pseudo-spin pattern with the $120^o$ structure.Comment: 18 pages, 17 figures, Version to appear in J.Phys.Soc.Jp

Examining Lower Limb Injuries among Male Amateur Soccer Player

Amateur players far outnumbered professional athletes, but they are often under shadowed in literatures. Unlike professional athletes, amateur players may not possess the resources, knowledge or guidance in treating sports injuries. Soccer is one of the popular sports with fewer literatures addressing amateur players. Quantitative method was used for data collection and analysis. The practical contribution of this study lies in terms of the exploring of risks factors leading to lower limb injuries, most common type and area of injuries faced by amateur soccer players in contrast with professional players. Preventive measures were also discussed. The implications of these findings are valuable to coaches, physical therapists and governments for understanding amateur players and arouse public awareness on health and safety