Nonrelativistic Chern-Simons Vortices on the Torus

A classification of all periodic self-dual static vortex solutions of the Jackiw-Pi model is given. Physically acceptable solutions of the Liouville equation are related to a class of functions which we term Omega-quasi-elliptic. This class includes, in particular, the elliptic functions and also contains a function previously investigated by Olesen. Some examples of solutions are studied numerically and we point out a peculiar phenomenon of lost vortex charge in the limit where the period lengths tend to infinity, that is, in the planar limit.Comment: 25 pages, 2+3 figures; improved exposition, corrected typos, added one referenc

Spin Hall effect in the kagome lattice with Rashba spin-orbit interaction

We study the spin Hall effect in the kagom\'{e} lattice with Rashba spin-orbit coupling. The conserved spin Hall conductance $\sigma_{xy}^{s}$ (see text) and its two components, i.e., the conventional term $\sigma_{xy}^{s0}$ and the spin-torque-dipole term $\sigma_{xy}^{s\tau}$, are numerically calculated, which show a series of plateaus as a function of the electron Fermi energy $\epsilon_{F}$. A consistent two-band analysis, as well as a Berry-phase interpretation, is also given. We show that these plateaus are a consequence of the various Fermi-surface topologies when tuning $\epsilon_{F}$. In particular, we predict that compared to the case with the Fermi surface encircling the $\mathbf{\Gamma}$ point in the Brillouin zone, the amplitude of the spin Hall conductance with the Fermi surface encircling the $\mathbf{K}$ points is twice enhanced, which makes it highly meaningful in the future to systematically carry out studies of the $\mathbf{K}$-valley spintronics.Comment: 7 pages, 3 figures. Phys. Rev. B (in press

Fixing All Moduli in a Simple F-Theory Compactification

We discuss a simple example of an F-theory compactification on a Calabi-Yau fourfold where background fluxes, together with nonperturbative effects from Euclidean D3 instantons and gauge dynamics on D7 branes, allow us to fix all closed and open string moduli. We explicitly check that the known higher order corrections to the potential, which we neglect in our leading approximation, only shift the results by a small amount. In our exploration of the model, we encounter interesting new phenomena, including examples of transitions where D7 branes absorb O3 planes, while changing topology to preserve the net D3 charge.Comment: 68 pages, 19 figures; v2: references adde

Orthogonal methods based ant colony search for solving continuous optimization problems

Research into ant colony algorithms for solving continuous optimization problems forms one of the most significant and promising areas in swarm computation. Although traditional ant algorithms are designed for combinatorial optimization, they have shown great potential in solving a wide range of optimization problems, including continuous optimization. Aimed at solving continuous problems effectively, this paper develops a novel ant algorithm termed "continuous orthogonal ant colony" (COAC), whose pheromone deposit mechanisms would enable ants to search for solutions collaboratively and effectively. By using the orthogonal design method, ants in the feasible domain can explore their chosen regions rapidly and e±ciently. By implementing an "adaptive regional radius" method, the proposed algorithm can reduce the probability of being trapped in local optima and therefore enhance the global search capability and accuracy. An elitist strategy is also employed to reserve the most valuable points. The performance of the COAC is compared with two other ant algorithms for continuous optimization of API and CACO by testing seventeen functions in the continuous domain. The results demonstrate that the proposed COAC algorithm outperforms the others

Bias-voltage dependence of the magneto-resistance in ballistic vacuum tunneling: Theory and application to planar Co(0001) junctions

Motivated by first-principles results for jellium and by surface-barrier shapes that are typically used in electron spectroscopies, the bias voltage in ballistic vacuum tunneling is treated in a heuristic manner. The presented approach leads in particular to a parameterization of the tunnel-barrier shape, while retaining a first-principles description of the electrodes. The proposed tunnel barriers are applied to Co(0001) planar tunnel junctions. Besides discussing main aspects of the present scheme, we focus in particular on the absence of the zero-bias anomaly in vacuum tunneling.Comment: 19 pages with 8 figure

A new method for grain refinement in magnesium alloy: High speed extrusion machining

Magnesium alloys have received broad attentions in industry due to their competitive strength to density ratio, but the poor ductility and strength limit their wide range of applications as engineering materials. A novel severe plastic deformation (SPD) technique of high speed extrusion machining (HSEM) was used here. This method could improve the aforementioned disadvantages of magnesium alloys by one single processing step. In this work, systematic HSEM experiments with different chip thickness ratios were conducted for magnesium alloy AZ31B. The microstructure of the chips reveals that HSEM is an effective SPD method for attaining magnesium alloys with different grain sizes and textures. The magnesium alloy with bimodal grain size distribution has increased mechanical properties than initial sample. The electron backscatter diffraction (EBSD) analysis shows that the dynamic recrystallization (DRX) affects the grain refinement and resulting hardness in AZ31B. Based on the experimental observations, a new theoretical model is put forward to describe the effect of DRX on materials during HSEM. Compared with the experimental measurements, the theoretical model is effective to predict the mechanical property of materials after HSEM. (c) 2015 Elsevier B.V. All rights reserved

Scalar brane backgrounds in higher order curvature gravity

We investigate maximally symmetric brane world solutions with a scalar field. Five-dimensional bulk gravity is described by a general lagrangian which yields field equations containing no higher than second order derivatives. This includes the Gauss-Bonnet combination for the graviton. Stability and gravitational properties of such solutions are considered, and we particularily emphasise the modifications induced by the higher order terms. In particular it is shown that higher curvature corrections to Einstein theory can give rise to instabilities in brane world solutions. A method for analytically obtaining the general solution for such actions is outlined. Genericaly, the requirement of a finite volume element together with the absence of a naked singularity in the bulk imposes fine-tuning of the brane tension. A model with a moduli scalar field is analysed in detail and we address questions of instability and non-singular self-tuning solutions. In particular, we discuss a case with a normalisable zero mode but infinite volume element.Comment: published versio

Design of AMBA AXI4 protocol for System-on-Chip communication

Advanced microcontroller bus architecture (AMBA) protocol family provides metric-driven verification of protocol compliance, enabling comprehensive testing of interface intellectual property (IP) blocks and system-on-chip (SoC) designs. The AMBA advanced extensible interface 4 (AXI4) update to AMBA AXI3 includes the following: support for burst lengths up to 256 beats, updated write response requirements, removal of locked transactions and AXI4 also includes information on the interoperability of components. AMBA AXI4 protocol system supports 16 masters and 16 slaves interfacing. This paper presents a work aimed to design the AMBA AXI4 protocol modeled in Verilog hardware description language (HDL) and simulation results for read and write operation of data and address are shown in Verilog compiler simulator (VCS) tool. The operating frequency is set to 100MHz. Two test cases are run to perform multiple read and multiple write operations. To perform single read operation module takes 160ns and for single write operation it takes 565ns

Involving private healthcare practitioners in an urban NCD sentinel surveillance system: lessons learned from Pune, India

Background: Despite the rising impact of non-communicable diseases (NCDs) on public health in India, lack of quality data and routine surveillance hampers the planning process for NCD prevention and control. Current surveillance programs focus largely on communicable diseases and do not adequately include the private healthcare sector as a major source of care in cities. Objective: The objective of the study was to conceptualize, implement, and evaluate a prototype for an urban NCD sentinel surveillance system among private healthcare practitioners providing primary care in Pune, India. Design: We mapped all private healthcare providers in three selected areas of the city, conducted a knowledge, attitude, and practice survey with regard to surveillance among 258 consenting practitioners, and assessed their willingness to participate in a routine NCD surveillance system. In total, 127 practitioners agreed and were included in a 6-month surveillance study. Data on first time diagnoses of 10 selected NCDs alongside basic demographic and socioeconomic patient information were collected onsite on a monthly basis using a paper-based register. Descriptive and regression analyses were performed. Results: In total, 1,532 incident cases were recorded that mainly included hypertension (n622, 41%) and diabetes (n460, 30%). Dropout rate was 10% (n13). The monthly reporting consistency was quite constant, with the majority (n63, 50%) submitting 110 cases in 6 months. Average number of submitted cases was highest among allopathic practitioners (17.4). A majority of the participants (n104, 91%) agreed that the surveillance design could be scaled up to cover the entire city. Conclusions: The study indicates that private primary healthcare providers (allopathic and alternate medicine practitioners) play an important role in the diagnosis and treatment of NCDs and can be involved in NCD surveillance, if certain barriers are addressed. Main barriers observed were lack of regulation of the private sector, cross-practices among different systems of medicine, limited clinic infrastructure, and knowledge gaps about disease surveillance. We suggest a voluntary augmented sentinel NCD surveillance system including public and private healthcare facilities at all levels of care

Attitudes of undergraduates towards mental illness: A comparison between nursing and business management students in India

Background. Mental illness is an important public health issue worldwide; stigmatisation and negative attitudes towards people with mental illness are widespread among the general public. However, little is known about the attitudes of undergraduates to mental illness.  Purpose. To compare the attitudes towards mental illness among undergraduates enrolled in nursing courses v. those enrolled in Bachelor of Business Management (BBM) courses.  Methods. A cross-sectional descriptive design was adopted for the present study. A total of 268 undergraduates were selected to complete the Attitude Scale for Mental Illness (ASMI) and the Opinions about Mental Illness in the Chinese Community (OMICC) questionnaires.  Results. We found significant differences between the number of nursing and BBM students who agreed with statements posed by the questionnaires, e.g., that they would move out of their community if a mental health facility was established there (χ2=16.503, p<0.002), that they were not afraid of treated mentally ill people (χ2=15.279, p<0.004), and that people with mental illness tend to be violent (χ2=14.215, p<0.007) and dangerous (χ2=17.808, p<0.001). Nursing students disagreed that people with mental illness are easily identified (χ2=30.094, p<0.000), have a lower IQ (χ2=70.689, p<0.000) and should not have children (χ2=24.531, p<0.000). Nursing students were more benevolent than BBM students, as they agreed that people with mental illness can hold a job (χ2=49.992, p<0.000) and can return to their former position (χ2=11.596, p<0.021), that everyone faces the possibility of becoming mentally ill (χ2=38.726, p<0.000), and that one should not laugh at the mentally ill (χ2=17.407, p<0.002). Nursing students held less pessimistic attitudes, as they felt that the mentally ill should receive the same pay for the same job (χ2=10.669, p<0.031) and that the public are prejudiced towards people with mental illness (χ2=17.604, p<0.001). Conclusion. College students’ attitudes towards people with mental illness vary based on the course that they are enrolled in. Attitudes may be positively improved by revising curriculum design to incorporate educational sessions about mental illness. These are essential steps to combat discrimination, and potentially enhance the promotion of human rights for the mentally ill