Abstract-This paper presents a novel framework for the recognition of objects based on their silhouettes. The main idea is to measure the distance between two shapes as the minimum extent of deformation necessary for one shape to match the other. Since the space of deformations is very high-dimensional, three steps are taken to make the search practical: 1) define an equivalence class for shapes based on shock-graph topology, 2) define an equivalence class for deformation paths based on shock-graph transitions, and 3) avoid complexity-increasing deformation paths by moving toward shock-graph degeneracy. Despite these steps, which tremendously reduce the search requirement, there still remain numerous deformation paths to consider. To that end, we employ an edit-distance algorithm for shock graphs that finds the optimal deformation path in polynomial time. The proposed approach gives intuitive correspondences for a variety of shapes and is robust in the presence of a wide range of visual transformations. The recognition rates on two distinct databases of 99 and 216 shapes each indicate highly successful within category matches (100 percent in top three matches), which render the framework potentially usable in a range of shape-based recognition applications.

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Recent developments in the field of spin dynamics-like the interaction of charge and heat currents with magnons, the quasi-particles of spin waves-opens the perspective for novel information processing concepts and potential applications purely based on magnons without the need of charge transport. The challenges related to the realization of advanced concepts are the spin-wave transport in two-dimensional structures and the transfer of existing demonstrators to the micro-or even nanoscale. Here we present the experimental realization of a microstructured spin-wave multiplexer as a fundamental building block of a magnon-based logic. Our concept relies on the generation of local Oersted fields to control the magnetization configuration as well as the spin-wave dispersion relation to steer the spin-wave propagation in a Y-shaped structure. Thus, the present work illustrates unique features of magnonic transport as well as their possible utilization for potential technical applications.

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Spin waves are the elementary excitations of the spin system in a magnetically ordered material state and magnons are their quasi particles. In the following article, we will discuss Brillouin light scattering (BLS) spectroscopy which is now a well-established tool for the characterization of spin waves. BLS is the inelastic scattering of light from spin waves and confers several benefits: the ability to map the spin-wave intensity with spatial resolution and high sensitivity as well as the potential for the simultaneous detection of frequency and wave vector. For several decades, the field of spin waves gained huge interest by the scientific community due to its relevance regarding fundamental issues in spin dynamics. Recently, the ongoing research in the field of magnonics has put particular emphasis on the high potential of spin waves regarding information technology. Opposed to charge-based schemes in conventional electronics and spintronics, magnons are charge-free currents of angular momentum, and, therefore, less subject to dissipative scattering processes. These ideas have propelled the quest for concepts to guide and manipulate spin-wave transport as well as for the miniaturization of spin-wave conduits towards sub-micrometer dimensions. For the further development of potential spin-wave-based devices, the ability to directly observe spin-wave propagation with spatial resolution is crucial. As an optical technique, BLS allows for a sub-micron space resolution by the implementation of a microscope objective in the optical setup. Over the last decade, this micro-focus BLS technique has become an established method for the investigation of spin waves in microstructured magnetic elements and proved its value in particular regarding magnonics. In this article, we will discuss the basic principles of BLS and illustrate the experimental optical setup. Particular emphasis will be put on the implementation of the high spatial resolution of BLS microscopes as well as on their computer based operation and automated sample positioning. Owing to these improvements in ease of use as well as experimental applicability, the BLS technique has maintained its relevance for investigations on spin waves in miniaturized magnetic structures as will be illustrated by a selection of experiments.

In the research field of magnonics, it is envisaged that spin waves will be used as information carriers, promoting operation based on their wave properties. However, the field still faces major challenges. To become fully competitive, novel schemes for energy-efficient control of spin-wave propagation in two dimensions have to be realized on much smaller length scales than used before. In this Letter, we address these challenges with the experimental realization of a novel approach to guide spin waves in reconfigurable, nano-sized magnonic waveguides. For this purpose, we make use of two inherent characteristics of magnetism: the non-volatility of magnetic remanence states and the nanometre dimensions of domain walls formed within these magnetic configurations. We present the experimental observation and micromagnetic simulations of spin-wave propagation inside nano-sized domain walls and realize a first step towards a reconfigurable domain-wall-based magnonic nanocircuitry.

In primary cells, overexpression of oncogenes such as RasV12 induces premature senescence rather than transformation. Senescence is an irreversible form of G1 arrest that requires the p19ARF/p53 and p16INK4a/pRB pathways and may suppress tumorigenesis in vivo. Here we show that the transcription factor C/EBPβ is required for RasV12‐induced senescence. C/EBPβ−/− mouse embryo fibroblasts (MEFs) expressing RasV12 continued to proliferate despite unimpaired induction of p19ARF and p53, and lacked morphological features of senescent fibroblasts. Enforced C/EBPβ expression inhibited proliferation of wild‐type MEFs and also slowed proliferation of p19Arf−/− and p53−/− cells, indicating that C/EBPβ acts downstream or independently of p19ARF/p53 to suppress growth. C/EBPβ was unable to inhibit proliferation of MEFs lacking all three RB family proteins or wild‐type cells expressing dominant negative E2F‐1 and, instead, stimulated their growth. C/EBPβ decreased expression of several E2F target genes and was associated with their promoters in chromatin immunoprecipitation assays, suggesting that C/EBPβ functions by repressing genes required for cell cycle progression. C/EBPβ is therefore a novel component of the RB:E2F‐dependent senescence program activated by oncogenic stress in primary cells.