Exact Nonperturbative Renormalization

We propose an exact renormalization group equation for Lattice Gauge Theories, that has no dependence on the lattice spacing. We instead relate the lattice spacing properties directly to the continuum convergence of the support of each local plaquette. Equivalently, this is formulated as a convergence prescription for a characteristic polynomial in the gauge coupling that allows the exact meromorphic continuation of a nonperturbative system arbitrarily close to the continuum limit.Comment: 12 page

Lorentz Covariance and the Dimensional Crossover of 2d-Antiferromagnets

We derive a lattice $\beta$-function for the 2d-Antiferromagnetic Heisenberg model, which allows the lattice interaction couplings of the nonperturbative Quantum Monte Carlo vacuum to be related directly to the zero-temperature fixed points of the nonlinear sigma model in the presence of strong interplanar and spin anisotropies. In addition to the usual renormalization of the gapful disordered state in the vicinity of the quantum critical point, we show that this leads to a chiral doubling of the spectra of excited states

Increased susceptibility of striatal mitochondria to calcium-induced permeability transition

Mitochondria were simultaneously isolated from striatum and cortex of adult rats and compared in functional assays for their sensitivity to calcium activation of the permeability transition. Striatal mitochondria showed an increased dose-dependent sensitivity to Ca2+compared with cortical mitochondria, as measured by mitochondrial depolarization, swelling, Ca2+uptake, reactive oxygen species production, and respiration. Ratios of ATP to ADP were lower in striatal mitochondria exposed to calcium despite equal amounts of ADP and ATP under respiring and nonrespiring conditions. The Ca2+-induced changes were inhibited by cyclosporin A or ADP. These responses are consistent with Ca2+activation of both low and high permeability pathways constituting the mitochondrial permeability transition. In addition to the striatal supersensitivity to induction of the permeability transition, cyclosporin A inhibition was less potent in striatal mitochondria. Immunoblots indicated that striatal mitochondria contained more cyclophilin D than cortical mitochondria. Thus striatal mitochondria may be selectively vulnerable to the permeability transition. Subsequent mitochondrial dysfunction could contribute to the initial toxicity of striatal neurons in Huntington's disease.</jats:p

Flipping the Classroom in Higher Education: A Design-Based Research Study to Develop a Flipped Classroom Framework

Over the past 20 years some higher education instructors have increased their technology use as a way to extend and enhance students’ understanding and move away from the traditional lecture approach. One recent strategy is to use a flipped classroom approach and have students use technology to access the lecture and other instructional resources outside the classroom; this leaves the in-class time to engage in active learning. However, at this time there are no empirically-based flipped classroom frameworks. The purpose of this study is to fill this gap in the academic literature and develop a framework. This will provide a springboard for other scholars and practitioners to further examine the efficacy of this specific blended approach to learning and effective approaches that can be adapted to meet the needs of their students

A scanning drift tube apparatus for spatio-temporal mapping of electron swarms

A "scanning" drift tube apparatus, capable of mapping of the spatio-temporal evolution of electron swarms, developing between two plane electrodes under the effect of a homogeneous electric field, is presented. The electron swarms are initiated by photoelectron pulses and the temporal distributions of the electron flux are recorded while the electrode gap length (at a fixed electric field strength) is varied. Operation of the system is tested and verified with argon gas, the measured data are used for the evaluation of the electron bulk drift velocity. The experimental results for the space-time maps of the electron swarms - presented here for the first time - also allow clear observation of deviations from hydrodynamic transport. The swarm maps are also reproduced by particle simulations

Innovation through Neurodiversity: Diversity is Beneficial

Those experiencing high rapport or strong social connection are more likely to copy each other, or emulate each other’s ideas, either consciously or sub-consciously. In this study, we use this phenomenon to examine whether neurotype match or mismatch impacts degree of imitation in a creative task. We asked 71 participants in neurodiverse pairs (including both autistic and non-autistic participants) and single-neurotype pairs (both autistic or both non-autistic), where one participant builds and one observes, to build the tallest possible tower from dried spaghetti and plasticine. We measured the height of each tower and photographed them to create a stimulus set. We then asked independent raters (n = 351, 62 autistic) to rate towers for degree of similarity. We hypothesised that lower similarity scores would be generated for towers created by people in neurodiverse pairs, showing positive innovation. Results showed towers built in the neurodiverse condition had least similarity, whereas towers built in the autistic and non-autistic conditions were significantly more similar. There was no difference in performance (height of tower) based on condition. Our results are the first to examine creativity within single-neurotype and neurodiverse pairs; they indicate that neurological diversity may be beneficial within a group setting. Subsequent research is required to examine how this interacts with divergent communication styles

Preserving the impossible: conservation of soft-sediment hominin footprint sites and strategies for three-dimensional digital data capture.

Human footprints provide some of the most publically emotive and tangible evidence of our ancestors. To the scientific community they provide evidence of stature, presence, behaviour and in the case of early hominins potential evidence with respect to the evolution of gait. While rare in the geological record the number of footprint sites has increased in recent years along with the analytical tools available for their study. Many of these sites are at risk from rapid erosion, including the Ileret footprints in northern Kenya which are second only in age to those at Laetoli (Tanzania). Unlithified, soft-sediment footprint sites such these pose a significant geoconservation challenge. In the first part of this paper conservation and preservation options are explored leading to the conclusion that to 'record and digitally rescue' provides the only viable approach. Key to such strategies is the increasing availability of three-dimensional data capture either via optical laser scanning and/or digital photogrammetry. Within the discipline there is a developing schism between those that favour one approach over the other and a requirement from geoconservationists and the scientific community for some form of objective appraisal of these alternatives is necessary. Consequently in the second part of this paper we evaluate these alternative approaches and the role they can play in a 'record and digitally rescue' conservation strategy. Using modern footprint data, digital models created via optical laser scanning are compared to those generated by state-of-the-art photogrammetry. Both methods give comparable although subtly different results. This data is evaluated alongside a review of field deployment issues to provide guidance to the community with respect to the factors which need to be considered in digital conservation of human/hominin footprints

On the possibility to supercool molecular hydrogen down to superfluid transition

Recent calculations by Vorobev and Malyshenko (JETP Letters, 71, 39, 2000) show that molecular hydrogen may stay liquid and superfluid in strong electric fields of the order of $4\times 10^7 V/cm$. I demonstrate that strong local electric fields of similar magnitude exist beneath a two-dimensional layer of electrons localized in the image potential above the surface of solid hydrogen. Even stronger local fields exist around charged particles (ions or electrons) if surface or bulk of a solid hydrogen crystal is statically charged. Measurements of the frequency shift of the $1 \to 2$ photoresonance transition in the spectrum of two-dimensional layer of electrons above positively or negatively charged solid hydrogen surface performed in the temperature range 7 - 13.8 K support the prediction of electric field induced surface melting. The range of surface charge density necessary to stabilize the liquid phase of molecular hydrogen at the temperature of superfluid transition is estimated.Comment: 5 pages, 2 figure