Image Similarity Metrics in Image Registration

Measures of image similarity that inspect the intensity probability distribution of the images have proved extremely popular in image registration applications. The joint entropy of the intensity distributions and the marginal entropies of the individual images are combined to produce properties such as resistance to loss of information in one image and invariance to changes in image overlap during registration. However information theoretic cost functions are largely used empirically. This work attempts to describe image similarity measures within a formal mathematical metric framework. Redefining mutual information as a metric is shown to lead naturally to the standardised variant, normalised mutual information

Non-Fermi-liquid behavior and anomalous suppression of Landau damping in layered metals close to ferromagnetism

We analyse the low-energy physics of nearly ferromagnetic metals in two spatial dimensions using the functional renormalization group technique. We find a new low-energy fixed point, at which the fermionic (electron-like) excitations are non-Fermi-liquid ($z_f = 13/10$) and the magnetic fluctuations exhibit an anomalous Landau damping whose rate vanishes as $\Gamma_{\bf q} \sim \vert {\bf q} \vert^{3/5}$ in the low-$\vert {\bf q} \vert$ limit. We discuss this renormalization of the Landau-damping exponent, which is the major novel prediction of our work, and highlight the possible link between that renormalization and neutron-scattering data on UGe$_2$ and related compounds. Implications of our analysis for YFe$_2$Al$_{10}$ are also discussed.Comment: 5 pages, 3 figures; action modified to include spin of fermions, resulting in quantitative changes to exponents but same essential physic

Magnetic induction plasma engine Final report

Wall interaction reduction in magnetic induction plasma accelerato

Are All Static Black Hole Solutions Spherically Symmetric?

The static black hole solutions to the Einstein-Maxwell equations are all spherically symmetric, as are many of the recently discovered black hole solutions in theories of gravity coupled to other forms of matter. However, counterexamples demonstrating that static black holes need not be spherically symmetric exist in theories, such as the standard electroweak model, with electrically charged massive vector fields. In such theories, a magnetically charged Reissner-Nordstrom solution with sufficiently small horizon radius is unstable against the development of a nonzero vector field outside the horizon. General arguments show that, for generic values of the magnetic charge, this field cannot be spherically symmetric. Explicit construction of the solution shows that it in fact has no rotational symmetry at all.Comment: 6 pages, plain TeX. Submitted to GRF Essay Competitio

How training can fix the existential crisis in science journalism

Science Journalism has been through a huge transition period in the past two decades as digital outlets compete with print media — and that transition is continuing. It’s left many science journalists unsure of their place in this new ecosystem and unsure of how best to use the new toolsthey have been presented with, such as social media. Now is an important time for training in this sector to ensure that journalists — and the publications they work for — can find their place again. There is also a real need for training for new writers — to bridge the gap between their degree and their first job as a journalist

The new commodities of the new media landscape

The ‘traditional’ media industry — newspapers and magazines and the like — have had a difficult time lately thanks to increasing competition online. This book’s chapters consider ways the traditional media can reinvent themselves to secure their future. Two key themes that emerge from the chapters are the importance of building communities and the increasing role of credibility in today’s highly competitive media landscape. While this book does not focus on the science media, many of the conclusions are relevant to it, in fact some are cause for comfort for those involved with science journalism

Processing of DMSP magnetic data: Handbook of programs, tapes, and datasets

The DMSP F-7 satellite was an operational Air Force meteorological satellite which carried a magnetometer for geophysical measurements. The magnetometer was located within the body of the spacecraft in the presence of large spacecraft fields. In addition to stray magnetic fields, the data have inherent position and time inaccuracies. Algorithms were developed to identify and remove time varying magnetic field noise from the data. These algorithms are embodied in an automated procedure which fits a smooth curve through the data and then identifies outliers and which filters the predominant Fourier component of noise from the data. Techniques developed for Magsat were then modified and used to attempt determination of the spacecraft fields, of any rotation between the magnetometer axes and the spacecraft axes, and of any scale changes within the magnetometer itself. Software setup and usage are documented and program listings are included in the Appendix. The initial and resulting data are archived on magnetic cartridge and the formats are documented

Axisymmetric non-abelian BPS monopoles from G_2 metrics

Exact $SU(2)\times U(1)$ self-gravitating BPS global monopoles in four dimensions are constructed by dimensional reduction of eight dimensional metrics with $G_2$ holonomy asymptotic to cones over $S^3\times S^3$. The solutions carry two topological charges in an interesting way. They are generically axially but not spherically symmetric. This last fact is related to the isometries and asymptotic topology of the $G_2$ metrics. It is further shown that some $G_2$ metrics known numerically reduce to supersymmetric cosmic strings.Comment: Latex. 1+21 pages. References update

Exploring the meaning in meaningful coincidences: an interpretative phenomenological analysis of synchronicity in therapy

Synchronicity experiences (SEs) are defined as psychologically meaningful connections between inner events (e.g., thought, dream or vision) and one or more external events occurring simultaneously or at a future point in time. There has been limited systematic research that has investigated the phenomenology of SEs in therapy. This study aimed to redress this by exploring the process and nature of such experiences from the perspective of the practitioner. Interpretative phenomenological analysis (IPA; Smith, Flowers, & Larkin, 2009) was used to interview a purposive sample of nine practitioners who reported SEs in their therapeutic sessions. Semi-structured face-to-face interviews were conducted with three counsellors, three psychologists and three psychotherapists, and focused on how participants make sense of their experiences of synchronicity in therapy. Three superordinate themes were identified: Sense of connectedness, therapeutic process, and professional issues. Findings suggest that SEs can serve to strengthen the therapeutic relationship and are perceived as useful harbingers of information about the therapeutic process, as well as being a means of overcoming communication difficulties, as they are seen to provide insights into the client’s experiencing of themselves and others, regardless of whether or not the SE is acknowledged by the client or disclosed by the therapist

Porometry, porosimetry, image analysis and void network modelling in the study of the pore-level properties of filters

We present fundamental and quantitative comparisons between the techniques of porometry (or flow permporometry), porosimetry, image analysis and void network modelling for seven types of filter, chosen to encompass the range of simple to complex void structure. They were metal, cellulose and glass fibre macro- and meso-porous filters of various types. The comparisons allow a general re-appraisal of the limitations of each technique for measuring void structures. Porometry is shown to give unrealistically narrow void size distributions, but the correct filtration characteristic when calibrated. Shielded mercury porosimetry can give the quaternary (sample-level anisotropic) characteristics of the void structure. The first derivative of a mercury porosimetry intrusion curve is shown to underestimate the large number of voids, but this error can be largely corrected by the use of a void network model. The model was also used to simulate the full filtration characteristic of each sample, which agreed with the manufacturer's filtration ratings. The model was validated through its correct a priori simulation of absolute gas permeabilities for track etch, cellulose nitrate and sintered powder filters. © 2011 Elsevier Ltd