High Velocity Runaway Binaries from Supernovae in Triple Systems

Recent studies on hypervelocity stars (HVSs) have generated a need to understand the high velocity limits of binary systems. If runaway binary systems with high movement speeds well in excess of 200km/s were to exist, it would have implications on how HVS candidates are selected, and our current understanding of how they form needs to be reinforced. In this paper, we explore the possibility that such high velocity runaway binaries (HVRBs) can be engendered by supernova explosions of the tertiary in close hierarchical triple systems. We find that such explosions can lead to significant remnant binary velocities, and demonstrate via constraining the velocity distribution of such HVRBs that this mechanism can lead to binaries with centre of mass velocities of 350 km/s or more, relative to the original centre of mass of the progenitor triple system. This translates into potential observations of binaries with velocities high enough to escape the Galaxy, once the Galactic rotational velocity and objects of Large Magellanic Cloud origins are considered.Comment: 5 pages, 2 figure

Probabilistic Teleportation of Two-Particle State of General Formation in Ion Trap

We propose a scheme for probabilistic teleportation of an unknown two-particle state of general formation in ion trap. It is shown that one can realize experimentally this teleportation protocol of two-particle state with presently available techniques.Comment: 4 pages, no figur

A decentralized proximal-gradient method with network independent step-sizes and separated convergence rates

This paper proposes a novel proximal-gradient algorithm for a decentralized optimization problem with a composite objective containing smooth and non-smooth terms. Specifically, the smooth and nonsmooth terms are dealt with by gradient and proximal updates, respectively. The proposed algorithm is closely related to a previous algorithm, PG-EXTRA \cite{shi2015proximal}, but has a few advantages. First of all, agents use uncoordinated step-sizes, and the stable upper bounds on step-sizes are independent of network topologies. The step-sizes depend on local objective functions, and they can be as large as those of the gradient descent. Secondly, for the special case without non-smooth terms, linear convergence can be achieved under the strong convexity assumption. The dependence of the convergence rate on the objective functions and the network are separated, and the convergence rate of the new algorithm is as good as one of the two convergence rates that match the typical rates for the general gradient descent and the consensus averaging. We provide numerical experiments to demonstrate the efficacy of the introduced algorithm and validate our theoretical discoveries

On the complexity of k-rainbow cycle colouring problems

An edge-coloured cycle is $rainbow$ if all edges of the cycle have distinct colours. For $k\geq 1$, let $\mathcal{F}_{k}$ denote the family of all graphs with the property that any $k$ vertices lie on a cycle. For $G\in \mathcal{F}_{k}$, a $k$-$rainbow$ $cycle$ $colouring$ of $G$ is an edge-colouring such that any $k$ vertices of $G$ lie on a rainbow cycle in $G$. The $k$-$rainbow$ $cycle$ $index$ of $G$, denoted by $crx_{k}(G)$, is the minimum number of colours needed in a $k$-rainbow cycle colouring of $G$. In this paper, we restrict our attention to the computational aspects of $k$-rainbow cycle colouring. First, we prove that the problem of deciding whether $crx_1=3$ can be solved in polynomial time, but that of deciding whether $crx_1 \leq k$ is NP-Complete, where $k\geq 4$. Then we show that the problem of deciding whether $crx_2=3$ can be solved in polynomial time, but those of deciding whether $crx_2 \leq 4$ or $5$ are NP-Complete. Furthermore, we also consider the cases of $crx_3=3$ and $crx_3 \leq 4$. Finally, We prove that the problem of deciding whether a given edge-colouring (with an unbounded number of colours) of a graph is a $k$-rainbow cycle colouring, is NP-Complete for $k=1$, $2$ and $3$, respectively. Some open problems for further study are mentioned.Comment: 18 pages, to appear in Discrete Applied Mathematic

Hierarchical Saliency Detection on Extended CSSD

Complex structures commonly exist in natural images. When an image contains small-scale high-contrast patterns either in the background or foreground, saliency detection could be adversely affected, resulting erroneous and non-uniform saliency assignment. The issue forms a fundamental challenge for prior methods. We tackle it from a scale point of view and propose a multi-layer approach to analyze saliency cues. Different from varying patch sizes or downsizing images, we measure region-based scales. The final saliency values are inferred optimally combining all the saliency cues in different scales using hierarchical inference. Through our inference model, single-scale information is selected to obtain a saliency map. Our method improves detection quality on many images that cannot be handled well traditionally. We also construct an extended Complex Scene Saliency Dataset (ECSSD) to include complex but general natural images.Comment: 14 pages, 15 figure

Receding Horizon Consensus of General Linear Multi-agent Systems with Input Constraints: An Inverse Optimality Approach

It is desirable but challenging to fulfill system constraints and reach optimal performance in consensus protocol design for practical multi-agent systems (MASs). This paper investigates the optimal consensus problem for general linear MASs subject to control input constraints. Two classes of MASs including subsystems with semi-stable and unstable dynamics are considered. For both classes of MASs without input constraints, the results on designing optimal consensus protocols are first developed by inverse optimality approach. Utilizing the optimal consensus protocols, the receding horizon control (RHC)-based consensus strategies are designed for these two classes of MASs with input constraints. The conditions for assigning the cost functions distributively are derived, based on which the distributed RHC-based consensus frameworks are formulated. Next, the feasibility and consensus properties of the closed-loop systems are analyzed. It is shown that 1) the optimal performance indices under the inverse optimal consensus protocols are coupled with the network topologies and the system matrices of subsystems, but they are different for MASs with semi-stable and unstable subsystems; 2) the unstable modes of subsystems impose more stringent requirements for the parameter design; 3) the designed RHC-based consensus strategies can make the control input constraints fulfilled and ensure consensus for the closed-loop systems in both cases. But for MASs with semi-stable subsystems, the {\em convergent consensus} can be reached. Finally, two examples are provided to verify the effectiveness of the proposed results

High-precision nonadiabatic calculations of dynamic polarizabilities and hyperpolarizabilities for the lowlying vibrational-rotational states of hydrogen molecular ions

The static and dynamic electric multipolar polarizabilities and second hyperpolarizabilities of the H$_2^+$, D$_2^+$, and HD$^+$ molecular ions in the ground and first excited states are calculated nonrelativistically using explicitly correlated Hylleraas basis sets. The calculations are fully nonadiabatic; the Born-Oppenheimer approximation is not used. Comparisons are made with published theoretical and experimental results, where available. In our approach, no derivatives of energy functions nor derivatives of response functions are needed. In particular, we make contact with earlier calculations in the Born-Oppenheimer calculation where polarizabilities were decomposed into electronic, vibrational, and rotational contributions and where hyperpolarizabilities were determined from derivatives of energy functions. We find that the static hyperpolarizability for the ground state of HD$^+$ is seven orders of magnitude larger than the corresponding dipole polarizability. For the dipole polarizability of HD$^+$ in the first excited-state the high precision of the present method facilitates treatment of a near cancellation between two terms. For applications to laser spectroscopy of trapped ions we find tune-out and magic wavelengths for the HD$^+$ ion in a laser field. In addition, we also calculate the first few leading terms for long-range interactions of a hydrogen molecular ion interacting with a ground-state H, He, and Li atoms.Comment: 7 figure

Bid-Induced Release of AIF/EndoG from Mitochondria Causes Apoptosis of Macrophages during Infection with Leptospira interrogans.

Leptospirosis is a global zoonotic infectious disease caused by pathogenic Leptospira species. Leptospire-induced macrophage apoptosis through the Fas/FasL-caspase-8/3 pathway plays an important role in the survival and proliferation of the pathogen in hosts. Although, the release of mitochondrial apoptosis-inducing factor (AIF) and endonuclease G (EndoG) in leptospire-infected macrophages has been described, the mechanisms linking caspase and mitochondrion-related host-cell apoptosis has not been determined. Here, we demonstrated that leptospire-infection induced apoptosis through mitochondrial damages in macrophages. Apoptosis was caused by the mitochondrial release and nuclear translocation of AIF and/or EndoG, leading to nuclear DNA fragmentation. However, the mitochondrion-related CytC-caspase-9/3 pathway was not activated. Next, we found that the release and translocation of AIF and/or EndoG was preceded by the activation of the BH3-interacting domain death agonist (Bid). Furthermore, our data demonstrated that caspase-8 was activated during the infection and caused the activation of Bid. Meanwhile, high reactive oxygen species (ROS) trigged by the infection caused the dephosphorylation of Akt, which also activated Bid. In conclusion, Bid-mediated mitochondrial release of AIF and/or EndoG followed by nuclear translocation is a major mechanism of leptospire- induced apoptosis in macrophages, and this process is modulated by both caspase-8 and ROS-Akt signal pathways

The radiative decays of 0++0^{++} and 1+−1^{+-} heavy mesons

The radiative decay is believed to be an ideal lab to study hadronic structure of newly observed resonances because the reactions are governed by only the electromagnetic interaction (tree level). However, to obtain correct theoretical values, one has to properly deal with the non-perturbative QCD effects in the wavefunction and hadronization. In this work we derive the formulas for the radiative decays of $0^{++}$ and $1^{-+}$ heavy mesons in the light front quark model (LFQM). Because $\mathcal{B}(\chi_{c0}\rightarrow J/\psi\gamma)$ is well measured, the theoretical evaluation of the transition rate can be used to test our approach. Within this theoretical framework, the width of $\chi_{b0}\rightarrow \Upsilon(1S)\gamma$ is evaluated. The formulas can be applied to identify the inner structures of new resonances, for example the isospin of $h_{c(b)}$ and the structure of $D_s(2317)$, via processes $h_c\rightarrow \eta_c\gamma$, $h_b\rightarrow \eta_b\gamma$ and $D_s(2317)\rightarrow D_s^*+\gamma$.Comment: 10 pages, 1 figure, Accepted by PR

First principles investigation of nitrogenated holey graphene

Nitrogenated holey graphene (NHG) has attracted much attention because of its semiconducting properties. However, the stacking orders and defect properties have not been investigated. In this letter, the structural and stacking properties of NHG are first investigated. We obtain the most stable stacking structure. Then, the band structures for bulk and multilayer NHG are studied. Impact of the strain on the band gaps and bond characteristics is discuss. In addition, we investigate formation mechanism of native defects of carbon vacancy (VC), carbon interstitial (Ci), nitrogen vacancy (VN), and nitrogen interstitial (Ni) in bulk NHG. Formation energies and transition levels of these native defects are assessed.Comment: 5 pages, 7 figure