Revisiting the Naturalness Problem -- Who is afraid of quadratic divergences? --

It is widely believed that quadratic divergences severely restrict natural constructions of particle physics models beyond the standard model (SM). Supersymmetry provides a beautiful solution, but the recent LHC experiments have excluded large parameter regions of supersymmetric extensions of the SM. It will now be important to reconsider whether we have been misinterpreting the quadratic divergences in field theories. In this paper, we revisit the problem from the viewpoint of the Wilsonian renormalization group and argue that quadratic divergences, which can always be absorbed into a position of the critical surface, should be simply subtracted in model constructions. Such a picture gives another justification to the argument that the scale invariance of the SM, except for the soft-breaking terms, is an alternative solution to the naturalness problem. It also largely broadens possibilities of model constructions beyond the SM since we just need to take care of logarithmic divergences, which cause mixings of various physical scales and runnings of couplings.Comment: 22 pages, 6 figures, version published in Phys. Rev.

Standardisation of magnetic nanoparticles in liquid suspension

Suspensions of magnetic nanoparticles offer diverse opportunities for technology innovation, spanning a large number of industry sectors from imaging and actuation based applications in biomedicine and biotechnology, through large-scale environmental remediation uses such as water purification, to engineering-based applications such as position-controlled lubricants and soaps. Continuous advances in their manufacture have produced an ever-growing range of products, each with their own unique properties. At the same time, the characterisation of magnetic nanoparticles is often complex, and expert knowledge is needed to correctly interpret the measurement data. In many cases, the stringent requirements of the end-user technologies dictate that magnetic nanoparticle products should be clearly defined, well characterised, consistent and safe; or to put it another way—standardised. The aims of this document are to outline the concepts and terminology necessary for discussion of magnetic nanoparticles, to examine the current state-of-the-art in characterisation methods necessary for the most prominent applications of magnetic nanoparticle suspensions, to suggest a possible structure for the future development of standardisation within the field, and to identify areas and topics which deserve to be the focus of future work items. We discuss potential roadmaps for the future standardisation of this developing industry, and the likely challenges to be encountered along the way

Hawking Radiation of Black p-Branes from Gravitational Anomaly

We investigate the Hawking radiation of black $p$-branes of superstring theories using the method of anomaly cancelation, specially, we use the method of [S. Iso, H. Umetsu and F. Wilczek, {\sl Phys. Rev. Lett.} {\bf 96}, 151302 (2006); {\sl Phys. Rev. D} {\bf 74}, 044017 (2006)]. The metrics of black $p$-branes are spherically symmetric, but not the Schwarzschild type. In order to simplify the calculation, we first make a coordinate transformation to transform the metric to the Schwarzschild type. Then we calculate its energy-momentum flux from the method of anomaly cancelation of the above mentioned references. The obtained energy-momentum flux is equal to a black body radiation, the thermodynamic temperature of the radiation is equal to its Hawking temperature. And we find that the results are not changed for the original non-Schwarzschild type spherically symmetric metric.Comment: 19 pages Latex, some mistakes correcte

Understanding the fidelity effect when evaluating games with children

There have been a number of studies that have compared evaluation results from prototypes of different fidelities but very few of these are with children. This paper reports a comparative study of three prototypes ranging from low fidelity to high fidelity within the context of mobile games, using a between subject design with 37 participants aged 7 to 9. The children played a matching game on either an iPad, a paper prototype using screen shots of the actual game or a sketched version. Observational data was captured to establish the usability problems, and two tools from the Fun Toolkit were used to measure user experience. The results showed that there was little difference for user experience between the three prototypes and very few usability problems were unique to a specific prototype. The contribution of this paper is that children using low-fidelity prototypes can effectively evaluate games of this genre and style

Effect of Texel crossbreeding on productive traits, carcass and meat quality of Segureña lambs

BACKGROUND: The present study aimed to assess the effect of crossbreeding a local breed (Segureña, S × S) with Texel as the sire line (Texel × Segureña crossbred, T × S) on productive traits and meat quality attributes. Sixty-eight lambs (both males and females) from each genotype, weaned at about 45 days old and intensively fed with concentrates and cereal straw ad libitum until they were 72 days old, were used to assess productive traits, and ten animals from each genotype were used to assess meat quality. RESULTS: The crossbreeding with Texel improves productivity, with a greater weight at birth (+1 kg) and at slaughter (+3 kg) and a greater average daily gain (+29 g). T × S lambs had a better conformation, less carcass fatness, and higher content of muscle (+45 g kg -1 ) as opposed to a lower fat content (-50.6 g kg -1 ). With regard to meat quality, crossbreeding with Texel provided a meat with a higher protein content (+4 g kg -1 ) and a lower oleic acid content (21% less), although the differences were very scarce from a sensory point of view, and non-existent with respect to instrumental quality. CONCLUSION: Crossbreeding could comprise a useful tool in the production of ovine meat in local breeds, such as Segureña, within the Mediterranean Area, and, consequently, a way of increasing the profitability of the farms

Anomalies, Horizons and Hawking radiation

Hawking radiation is obtained from the Reissner-Nordstr\"{o}m blackhole with a global monopole and the Garfinkle-Horowitz-Strominger blackhole falling in the class of the most general spherically symmetric blackholes $(\sqrt{-g}\neq1)$, using only chiral anomaly near the event horizon and covariant boundary condition at the event horizon. The approach differs from the anomaly cancellation approach since apart from the covariant boundary condition, the chiral anomaly near the horizon is the only input to derive the Hawking flux.Comment: minor corrections made, To appear in Euro. Phys. Letter

On the forward-backward correlations in a two-stage scenario

It is demonstrated that in a two-stage scenario with elementary Poissonian emitters of particles (colour strings) arbitrarily distributed in their number and average multiplicities, the forward- backward correlations are completely determined by the final distribution of the forward particles. The observed linear form of the correlations then necessarily requires this distribution to have a negative binomial form. For emitters with a negative binomial distribution of the produced particles distributed so as to give the final distribution also of a negative binomial form, the forward-backward correlations have an essentially non-linear form, which disagrees with the experimental data.Comment: 14 pages in LaTex, 1 figure in Postscrip

Transport Coefficients of Gluon Plasma

Transport coefficients of gluon plasma are calculated for a SU(3) pure gauge model by lattice QCD simulations on $16^3 \times 8$ and $24^3 \times 8$ lattices. Simulations are carried out at a slightly above the deconfinement transition temperature $T_c$, where a new state of matter is currently being pursued in RHIC experiments. Our results show that the ratio of the shear viscosity to the entropy is less than one and the bulk viscosity is consistent with zero in the region, $1.4 \leq T/T_c \leq 1.8$.Comment: 10 pages, Late

Characterisation of the topography of metal additive surface features with different measurement technologies

The challenges of measuring the surface topography of metallic surfaces produced by additive manufacturing are investigated. The differences between measurements made using various optical and non-optical technologies, including confocal and focus-variation microscopy, coherence scanning interferometry and x-ray computed tomography, are examined. As opposed to concentrating on differences which may arise through computing surface texture parameters from measured topography datasets, a comparative analysis is performed focussing on investigation of the quality of the topographic reconstruction of a series of surface features. The investigation is carried out by considering the typical surface features of a metal powder-bed fusion process: weld tracks, weld ripples, attached particles and surface recesses. Results show that no single measurement technology provides a completely reliable rendition of the topographic features that characterise the metal powder-bed fusion process. However, through analysis of measurement discrepancies, light can be shed on where instruments are more susceptible to error, and why differences between measurements occur. The results presented in this work increase the understanding of the behaviour and performance of areal topography measurement, and thus promote the development of improved surface characterisation pipelines

Gravitational anomalies: a recipe for Hawking radiation

We explore the method of Robinson and Wilczek for deriving the Hawking temperature of a black hole. In this method, the Hawking radiation restores general covariance in an effective theory of near-horizon physics which otherwise exhibits a gravitational anomaly at the quantum level. The method has been shown to work for broad classes of black holes in arbitrary spacetime dimensions. These include static black holes, accreting or evaporating black holes, charged black holes, rotating black holes, and even black rings. In the case of charged and rotating black holes, the expected super-radiant current is also reproduced.Comment: 7 pages; This essay received an "Honorable Mention" in the 2007 Essay Competition of the Gravity Research Foundation; (v2) Short comments and references added; (v3) Minor revisions and updated references to agree with published versio