275 research outputs found

    Unselective regrowth of 1.5-μm InGaAsP multiple-quantum-well distributed-feedback buried heterostructure lasers

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    Unselective regrowth for fabricating 1.5-μm InGaAsP multiple-quantum well (MQW) distributed-feedback (DFB) buried heterostructure (BH) lasers is developed. The experimental results exhibit superior characteristics, such as a low threshold of 8.5mA, high slope efficiency of 0.55mW∕mA, circular-like far-field patterns, the narrow linewidth of 2.5MHz, etc. The high performance of the devices effectively proves the feasibility of the new method to fabricate buried heterostructure lasers

    Video Object Segmentation using Point-based Memory Network

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    Recent years have witnessed the prevalence of memory-based methods for Semi-supervised Video Object Segmentation (SVOS) which utilise past frames efficiently for label propagation. When conducting feature matching, fine-grained multi-scale feature matching has typically been performed using all query points, which inevitably results in redundant computations and thus makes the fusion of multi-scale results ineffective. In this paper, we develop a new Point-based Memory Network, termed as PMNet, to perform fine-grained feature matching on hard samples only, assuming that easy samples can already obtain satisfactory matching results without the need for complicated multi-scale feature matching. Our approach first generates an uncertainty map from the initial decoding outputs. Next, the fine-grained features at uncertain locations are sampled to match the memory features on the same scale. Finally, the matching results are further decoded to provide a refined output. The point-based scheme works with the coarsest feature matching in a complementary and efficient manner. Furthermore, we propose an approach to adaptively perform global or regional matching based on the motion history of memory points, making our method more robust against ambiguous backgrounds. Experimental results on several benchmark datasets demonstrate the superiority of our proposed method over state-of-the-art methods

    Periostin Is Essential for the Integrity and Function of the Periodontal Ligament During Occlusal Loading in Mice

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141255/1/jper1480.pd

    In vivo impact of a 4 bp deletion mutation in the DLX3 gene on bone development

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    AbstractDistal-less 3 (DLX3) gene mutations are etiologic for Tricho-Dento-Osseous syndrome. To investigate the in vivo impact of mutant DLX3 on bone development, we established transgenic (TG) mice expressing the c.571_574delGGGG DLX-3 gene mutation (MT-DLX3) driven by a mouse 2.3 Col1A1 promoter. Microcomputed tomographic analyses demonstrated markedly increased trabecular bone volume and bone mineral density in femora from TG mice. In ex vivo experiments, TG mice showed enhanced differentiation of bone marrow stromal cells to osteoblasts and increased expression levels of bone formation markers. However, TG mice did not show enhanced dynamic bone formation rates in in vivo fluorochrome double labeling experiments. Osteoclastic differentiation capacities of bone marrow monocytes were reduced in TG mice in the presence of osteoclastogenic factors and the numbers of TRAP(+) osteoclasts on distal metaphyseal trabecular bone surfaces were significantly decreased. TRACP 5b and CTX serum levels were significantly decreased in TG mice, while IFN-γ levels were significantly increased. These data demonstrate that increased levels of IFN-γ decrease osteoclast bone resorption activities, contributing to the enhanced trabecular bone volume and mineral density in these TG mice. These data suggest a novel role for this DLX-3 mutation in osteoclast differentiation and bone resorption

    The fermion dynamical symmetry model for the even--even and even--odd nuclei in the Xe--Ba region

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    The even--even and even--odd nuclei 126^{126}Xe-132^{132}Xe and 131^{131}Ba-137^{137}Ba are shown to have a well-realized SO8⊃SO6⊃SO3SO_8 \supset SO_6 \supset SO_3 fermion dynamical symmetry. Their low-lying energy levels can be described by a unified analytical expression with two (three) adjustable parameters for even--odd (even--even) nuclei that is derived from the fermion dynamical symmetry model. Analytical expressions are given for wavefunctions and for E2E2 transition rates that agree well with data. The distinction between the FDSM and IBM SO6SO_6 limits is discussed. The experimentally observed suppression of the the energy levels with increasing SO5SO_5 quantum number Ï„\tau can be explained as a perturbation of the pairing interaction on the SO6SO_6 symmetry, which leads to an SO5SO_5 Pairing effect for SO6SO_6 nuclei.Comment: submitted to Phys. Rev. C, LaTeX, 31 pages, 8 figures with postscript files available on request at [email protected]

    Time-Dependent Partition-Free Approach in Resonant Tunneling Systems

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    An extended Keldysh formalism, well suited to properly take into account the initial correlations, is used in order to deal with the time-dependent current response of a resonant tunneling system. We use a \textit{partition-free} approach by Cini in which the whole system is in equilibrium before an external bias is switched on. No fictitious partitions are used. Besides the steady-state responses one can also calculate physical dynamical responses. In the noninteracting case we clarify under what circumstances a steady-state current develops and compare our result with the one obtained in the partitioned scheme. We prove a Theorem of asymptotic Equivalence between the two schemes for arbitrary time-dependent disturbances. We also show that the steady-state current is independent of the history of the external perturbation (Memory Loss Theorem). In the so called wide-band limit an analytic result for the time-dependent current is obtained. In the interacting case we propose an exact non-equilibrium Green function approach based on Time Dependent Density Functional Theory. The equations are no more difficult than an ordinary Mean Field treatment. We show how the scattering-state scheme by Lang follows from our formulation. An exact formula for the steady-state current of an arbitrary interacting resonant tunneling system is obtained. As an example the time-dependent current response is calculated in the Random Phase Approximation.Comment: final version, 18 pages, 9 figure

    Dark Energy and Neutrino CPT Violation

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    In this paper we study the dynamical CPT violation in the neutrino sector induced by the dark energy of the Universe. Specifically we consider a dark energy model where the dark energy scalar derivatively interacts with the right-handed neutrinos. This type of derivative coupling leads to a cosmological CPT violation during the evolution of the background field of the dark energy. We calculate the induced CPT violation of left-handed neutrinos and find the CPT violation produced in this way is consistent with the present experimental limit and sensitive to the future neutrino oscillation experiments, such as the neutrino factory.Comment: 10 pages, 2 figures. Typos corrected and references added. To be published in EPJ

    NMR and Mossbauer study of spin dynamics and electronic structure of Fe{2+x}V{1-x}Al and Fe2VGa

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    In order to assess the magnetic ordering process in Fe2VAl and the related material Fe2VGa, we have carried out nuclear magnetic resonance (NMR) and Mossbauer studies. 27Al NMR relaxation measurements covered the temperature range 4 -- 500 K in Fe(2+x)V(1-x)Al samples. We found a peak in the NMR spin-lattice relaxation rate, 27T1^-1, corresponding to the magnetic transitions in each of these samples. These peaks appear at 125 K, 17 K, and 165 K for x = 0.10, 0, and - 0.05 respectively, and we connect these features with critical slowing down of the localized antisite defects. Mossbauer measurements for Fe2VAl and Fe2VGa showed lines with no hyperfine splitting, and isomer shifts nearly identical to those of the corresponding sites in Fe3Al and Fe3Ga, respectively. We show that a model in which local band filling leads to magnetic regions in the samples, in addition to the localized antisite defects, can account for the observed magnetic ordering behavior.Comment: 5 pages, 3 figure
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