7,460 research outputs found

    The Conditional Colour-Magnitude Distribution: I. A Comprehensive Model of the Colour-Magnitude-Halo Mass Distribution of Present-Day Galaxies

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    We formulate a model of the conditional colour-magnitude distribution (CCMD) to describe the distribution of galaxy luminosity and colour as a function of halo mass. It consists of two populations of different colour distributions, dubbed pseudo-blue and pseudo-red, respectively, with each further separated into central and satellite galaxies. We define a global parameterization of these four colour-magnitude distributions and their dependence on halo mass, and we infer parameter values by simultaneously fitting the space densities and auto-correlation functions of 79 galaxy samples from the Sloan Digital Sky Survey defined by fine bins in the colour-magnitude diagram (CMD). The model deprojects the overall galaxy CMD, revealing its tomograph along the halo mass direction. The bimodality of the colour distribution is driven by central galaxies at most luminosities, though at low luminosities it is driven by the difference between blue centrals and red satellites. For central galaxies, the two pseudo-colour components are distinct and orthogonal to each other in the CCMD: at fixed halo mass, pseudo-blue galaxies have a narrow luminosity range and broad colour range, while pseudo-red galaxies have a narrow colour range and broad luminosity range. For pseudo-blue centrals, luminosity correlates tightly with halo mass, while for pseudo-red galaxies colour correlates more tightly (redder galaxies in more massive haloes). The satellite fraction is higher for redder and for fainter galaxies, with colour a stronger indicator than luminosity. We discuss the implications of the results and further applications of the CCMD model.Comment: 32 pages, 26 figures, accepted for publication in MNRA

    Steady Bell state generation via magnon-photon coupling

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    We show that parity-time (PT\mathcal{PT}) symmetry can be spontaneously broken in the recently reported energy level attraction of magnons and cavity photons. In the PT\mathcal{PT}-broken phase, magnon and photon form a high-fidelity Bell state with maximum entanglement. This entanglement is steady and robust against the perturbation of environment, in contrast to the general wisdom that expects instability of the hybridized state when the symmetry is broken. This anomaly is further understood by the compete of non-Hermitian evolution and particle number conservation of the hybridized system. As a comparison, neither PT\mathcal{PT}-symmetry broken nor steady magnon-photon entanglement is observed inside the normal level repulsion case. Our results may open a novel window to utilize magnon-photon entanglement as a resource for quantum technologies.Comment: 5 pages, 4 figure

    Digraph-based joint routing and resource allocation in software-defined backhaul networks

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    By decoupling the control plane from the data plane and providing programmability for network applications, software-defined network (SDN) is positioned to offer more efficient management, higher flexibility and better performance. Routing and resource allocation are two closely related applications in wireless networks. With close cooperation, better performance and lower complexity can be achieved in an SDN architecture. However, work that jointly studies routing and resource allocation is rarely seen. In this paper, the joint routing and resource allocation problem is investigated in OFDMA-based software-defined backhaul networks (SDBN). To exploit the SDN programmability, an SDBN system model is proposed, where the control panel can use high complexity algorithms in configuration phase in order to simplify algorithms in operation phases. Then the joint routing and resource allocation problem is formulated as a system throughput optimization problem. By constructing the interference digraph of the network and analysing the vertex degree characteristics, a digraph-based greedy algorithm (DBGA) is proposed. Simulation results have shown that, the proposed DBGA works well to increase the system throughput

    l-Peptide functionalized dual-responsive nanoparticles for controlled paclitaxel release and enhanced apoptosis in breast cancer cells

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    Nanoparticles and macromolecular carriers have been widely used to increase the efficacy of chemotherapeutics, largely through passive accumulation provided by their enhanced permeability and retention effect. However, the therapeutic efficacy of nanoscale anticancer drug delivery systems is severely truncated by their low tumor-targetability and inefficient drug release at the target site. Here, the design and development of novel l-peptide functionalized dual-responsive nanoparticles (l-CS-g-PNIPAM-PTX) for active targeting and effective treatment of GRP78-overexpressing human breast cancer in vitro and in vivo are reported. l-CS-g-PNIPAM-PTX NPs have a relative high drug loading (13.5%) and excellent encapsulation efficiency (74.3%) and an average diameter of 275 nm. The release of PTX is slow at pH 7.4 and 25 °C but greatly accelerated at pH 5.0 and 37 °C. MTT assays and confocal experiments showed that the l-CS-g-PNIPAM-PTX NPs possessed high targetability and antitumor activity toward GRP78 overexpressing MDA-MB-231 human breast cancer cells. As expected, l-CS-g-PNIPAM-PTX NPs could effectively treat mice bearing MDA-MB-231 human breast tumor xenografts with little side effects, resulting in complete inhibition of tumor growth and a high survival rate over an experimental period of 60 days. These results indicate that l-peptide-functionalized acid - and thermally activated - PTX prodrug NPs have a great potential for targeted chemotherapy in breast cancer.</p

    Reconsideration of Second Harmonic Generation from neat Air/Water Interface: Broken of Kleinman Symmetry from Dipolar Contribution

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    It has been generally accepted that there are significant quadrupolar and bulk contributions to the second harmonic generation (SHG) reflected from the neat air/water interface, as well as common liquid interfaces. Because there has been no general methodology to determine the quadrupolar and bulk contributions to the SHG signal from a liquid interface, this conclusion was reached based on the following two experimental phenomena. Namely, the broken of the macroscopic Kleinman symmetry, and the significant temperature dependence of the SHG signal from the neat air/water interface. However, because sum frequency generation vibrational spectroscopy (SFG-VS) measurement of the neat air/water interface observed no apparent temperature dependence, the temperature dependence in the SHG measurement has been reexamined and proven to be an experimental artifact. Here we present a complete microscopic analysis of the susceptibility tensors of the air/water interface, and show that dipolar contribution alone can be used to address the issue of broken of the macroscopic Kleinman symmetry at the neat air/water interface. Using this analysis, the orientation of the water molecules at the interface can be obtained, and it is consistent with the measurement from SFG-VS. Therefore, the key rationales to conclude significantly quadrupolar and bulk contributions to the SHG signal of the neat air/water interface can no longer be considered as valid as before. This new understanding of the air/water interface can shed light on our understanding of the nonlinear optical responses from other molecular interfaces as well
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