Leaping and Accelerometry: A Theoretical Approach

Accelerometry has always been a popular method of monitoring locomotor activity but its use is becoming more widespread due to the easy availability of low cost, low power sensors. However one of the major problems with interpreting accelerometer data is that rotation of the sensor alters the output and obtaining independent orientation information is currently difficult. For the specific case of leaping locomotion full orientation information is unecessary as long as an independent measure of height change is available such as can be obtained from a sensitive pressure sensor. Therefore a 4 channel logging system recording 3 accelerometry axes combined with a channel measuring pressure could be used to accurately assess leaping locomotion. This approach should also work for any locomotion where acceleration is limited to the vertical plane but in practice it may be restricted by the sensitivity and acquisition characteristics of the pressure measurement system. Ultimately it should be a useful addition to the range of measurements available for remote locomotor monitoring particularly for leaping species such as lemurs and other non-human primates

Aharanov-Bohm excitons at elevated temperatures in type-II ZnTe/ZnSe quantum dots

Optical emission from type-II ZnTe/ZnSe quantum dots demonstrates large and persistent oscillations in both the peak energy and intensity indicating the formation of coherently rotating states. Furthermore, the Aharanov-Bohm (AB) effect is shown to be remarkably robust and persists until 180K. This is at least one order of magnitude greater than the typical temperatures in lithographically defined rings. To our knowledge this is the highest temperature at which the AB effect has been observed in semiconductor structures

Convex hull estimation of mammalian body segment parameters

Obtaining accurate values for body segment parameters (BSPs) is fundamental in many biomechanical studies, particularly for gait analysis. Convex hulling, where the smallest-possible convex object that surrounds a set of points is calculated, has been suggested as an effective and time-efficient method to estimate these parameters in extinct animals, where soft tissues are rarely preserved. We investigated the effectiveness of convex hull BSP estimation in a range of extant mammals, to inform the potential future usage of this technique with extinct taxa. Computed tomography scans of both the skeleton and skin of every species investigated were virtually segmented. BSPs (the mass, position of the centre of mass and inertial tensors of each segment) were calculated from the resultant soft tissue segments, while the bone segments were used as the basis for convex hull reconstructions. We performed phylogenetic generalized least squares and ordinary least squares regressions to compare the BSPs calculated from soft tissue segments with those estimated using convex hulls, finding consistent predictive relationships for each body segment. The resultant regression equations can, therefore, be used with confidence in future volumetric reconstruction and biomechanical analyses of mammals, in both extinct and extant species where such data may not be available

Computational Techniques in Multispectral Image Processing : Application to the Syriac Galen Palimpsest

Multispectral and hyperspectral image analysis has experienced much development in the last decade. The application of these methods to palimpsests has produced significant results, enabling researchers to recover texts that would be otherwise lost under the visible overtext, by improving the contrast between the undertext and the overtext. In this paper we explore an extended number of multispectral and hyperspectral image analysis methods, consisting of supervised and unsupervised dimensionality reduction techniques, on a part of the Syriac Galen Palimpsest dataset (www.digitalgalen.net). Of this extended set of methods, eight methods gave good results: three were supervised methods Generalized Discriminant Analysis (GDA), Linear Discriminant Analysis (LDA), and Neighborhood Component Analysis (NCA); and the other five methods were unsupervised methods (but still used in a supervised way) Gaussian Process Latent Variable Model (GPLVM), Isomap, Landmark Isomap, Principal Component Analysis (PCA), and Probabilistic Principal Component Analysis (PPCA). The relative success of these methods was determined visually, using color pictures, on the basis of whether the undertext was distinguishable from the overtext, resulting in the following ranking of the methods: LDA, NCA, GDA, Isomap, Landmark Isomap, PPCA, PCA, and GPLVM. These results were compared with those obtained using the Canonical Variates Analysis (CVA) method on the same dataset, which showed remarkably accuracy (LDA is a particular case of CVA where the objects are classified to two classes).Comment: 29 February - 2 March 2016, Second International Conference on Natural Sciences and Technology in Manuscript Analysis, Centre for the study of Manuscript Cultures, Hamburg, German

The Syriac Galen Palimpsest::Research Methods and Latest Discoveries

In this article, we provide an update on the progress of the AHRC-funded Syriac Galen Palimpsest Project, which is directed by Peter E. Pormann at the University of Manchester. We also present a newly identified folio from Book 3 of Galen’s On Simple Drugs—a book hitherto not known to be represented in the manuscript. We offer some preliminary conclusions about the original medical manuscript’s codicological structure, particularly the composition of its quires and the sequence of hair and flesh sides of parchment. Finally, we outline our approach to analysing the undertext’s palaeography, with reference to the methodology devised by Ayda Kaplan

Strong light-matter coupling in bulk GaN-microcavities with double dielectric mirrors fabricated by two different methods

Two routes for the fabrication of bulk GaN microcavities embedded between two dielectric mirrors are described, and the optical properties of the microcavities thus obtained are compared. In both cases, the GaN active layer is grown by molecular beam epitaxy on (111) Si, allowing use of selective etching to remove the substrate. In the first case, a three period Al0.2Ga0.8N / AlN Bragg mirror followed by a lambda/2 GaN cavity are grown directly on the Si. In the second case, a crack-free 2,mu m thick GaN layer is grown, and progressively thinned to a final thickness of lambda. Both devices work in the strong coupling regime at low temperature, as evidenced by angle-dependent reflectivity or transmission experiments. However, strong light-matter coupling in emission at room temperature is observed only for the second one. This is related to the poor optoelectronic quality of the active layer of the first device, due to its growth only 250 nm above the Si substrate and its related high defect density. The reflectivity spectra of the microcavities are well accounted for by using transfer matrix calculations. (C) 2010 American Institute of Physics. [doi:10.1063/1.3477450