The status of traditional Scottish animal breeds and plant varieties and the implications for biodiversity

The aim of this scoping study was to evaluate the effects on Scottish biodiversity of changes in the use of traditional breeds and varieties. The overall objectives were: a) The evaluation of the importance of genetic loss from the reduction in use of these breeds and varieties, for example, the loss of unusual characteristics that might have been of particular local use. b) An assessment of the impacts of reduction in the ability to conduct further breeding or research on rare and traditional varieties and breeds. c) Identification of the loss of certain farming techniques associated with particular varieties and breeds. d) An assessment of possible losses of biodiversity associated with reduction in the use of these breeds and varieties and the farming systems associated with them

A pattern matching technique for measuring sediment displacement levels

This paper describes a novel technique for obtaining accurate, high (spatial) resolution measurements of sediment redeposition levels. A sequence of different random patterns are projected onto a sediment layer and captured using a high-resolution camera, producing a set of reference images. The same patterns are used to obtain a corresponding sequence of deformed images after a region of the sediment layer has been displaced and redeposited, allowing the use of a high-accuracy pattern matching algorithm to quantify the distribution of the redeposited sediment. A set of experiments using the impact of a vortex ring with a glass ballotini particle layer as the resuspension mechanism are described to test and illustrate the technique. The accuracy of the procedure is assessed using a known crater profile, manufactured to simulate the features of the craters observed in the experiments

Thermal intermodulation backaction in a high-cooperativity optomechanical system

The pursuit of room temperature quantum optomechanics with tethered nanomechanical resonators faces stringent challenges owing to extraneous mechanical degrees of freedom. An important example is thermal intermodulation noise (TIN), a form of excess optical noise produced by mixing of thermal noise peaks. While TIN can be decoupled from the phase of the optical field, it remains indirectly coupled via radiation pressure, implying a hidden source of backaction that might overwhelm shot noise. Here we report observation of TIN backaction in a high-cooperativity, room temperature cavity optomechanical system consisting of an acoustic-frequency Si$_3$N$_4$ trampoline coupled to a Fabry-P\'{e}rot cavity. The backaction we observe exceeds thermal noise by 20 dB and radiation pressure shot noise by 40 dB, despite the thermal motion being 10 times smaller than the cavity linewidth. Our results suggest that mitigating TIN may be critical to reaching the quantum regime from room temperature in a variety of contemporary optomechanical systems.Comment: 8 pages, 5 figure

Sediment resuspension and erosion by vortex rings

Particle resuspension and erosion induced by a vortex ringinteracting with a sediment layer was investigated experimentally using flow visualization (particle image velocimetry), high-speed video, and a recently developed light attenuation method for measuring displacements in bed level. Near-spherical sediment particles were used throughout with relative densities of 1.2–7 and diameters (d)(d) ranging between 90 and 1600 μm1600 μm. Attention was focused on initially smooth, horizontal bedforms with the vortex ring aligned to approach the bed vertically. Interaction characteristics were investigated in terms of the dimensionless Shields parameter, defined using the vortex-ring propagation speed. The critical conditions for resuspension (whereby particles are only just resuspended) were determined as a function of particle Reynolds number (based on the particle settling velocity and dd). The effects of viscous damping were found to be significant for d/δ<15d/δ<15, where δδ denotes the viscous sublayer thickness. Measurements of bed deformation were obtained during the interaction period, for a range of impact conditions. The (azimuthal) mean crater profile is shown to be generally self-similar during the interaction period, except for the most energetic impacts and larger sediment types. Loss of similarity occurs when the local bed slope approaches the repose limit, leading to collapse. Erosion, deposition, and resuspension volumes are analyzed as a function interaction time, impact condition, and sediment size

Geometry of stratified turbulent mixing: local alignment of the density gradient with rotation, shear and viscous dissipation

We introduce a geometric analysis of turbulent mixing in density-stratified flows based on the alignment of the density gradient in two orthogonal bases that are locally constructed from the velocity gradient tensor. The first basis connects diapycnal mixing to rotation and shearing motions, building on the recent 'rortex-shear decomposition' in stratified shear layers (Jiang et al., J. Fluid Mech. 947, A30, 2022), while the second basis connects mixing to the principal axes of the viscous dissipation tensor. Applying this framework to datasets taken in the stratified inclined duct laboratory experiment reveals that density gradients in locations of high shear tend to align preferentially (i) along the direction of minimum dissipation and (ii) normal to the plane spanned by the rotex and shear vectors. The analysis of the local alignment across increasingly turbulent flows offers new insights into the intricate relationship between the density gradient and dissipation, and thus diapycnal mixing

Analytics in online and offline language learning environments: the role of learning design to understand student online engagement

Language education has a rich history of research and scholarship focusing on the effectiveness of learning activities and the impact these have on student behaviour and outcomes. One of the basic assumptions in foreign language pedagogy and CALL in particular is that learners want to be able to communicate effectively with native speakers of their chosen language. Combining principles of learning analytics and Big Data with learning design, this study used a student activity based taxonomy adopted by the Open University UK to inform module design. The learning designs of four introductory and intermediary language education modules and online engagement of 2111 learners were contrasted using weekly learning design data. In this study, we aimed to explore how learning design decisions made by language teachers influenced students’ engagement in the VLE. Using fixed effect models, our findings indicated that 55% of variance of weekly online engagement in these four modules was explained by the way language teachers designed weekly learning design activities. Our learning analytics study highlights the potential affordances for CALL researchers to use the power of learning design and big data to explore and understand the complexities and dynamics of language learning for students and teachers

Neoproterozoic to early Paleozoic extensional and compressional history of East Laurentian margin sequences: The Moine Supergroup, Scottish Caledonides

Neoproterozoic siliciclastic-dominated sequences are widespread along the eastern margin of Laurentia and are related to rifting associated with the breakout of Laurentia from the supercontinent Rodinia. Detrital zircons from the Moine Supergroup, NW Scotland, yield Archean to early Neoproterozoic U-Pb ages, consistent with derivation from the Grenville-Sveconorwegian orogen and environs and accumulation post–1000 Ma. U-Pb zircon ages for felsic and associated mafic intrusions confirm a widespread pulse of extension-related magmatism at around 870 Ma. Pegmatites yielding U-Pb zircon ages between 830 Ma and 745 Ma constrain a series of deformation and metamorphic pulses related to Knoydartian orogenesis of the host Moinerocks. Additional U-Pb zircon and monazite data, and 40Ar/39Ar ages for pegmatites and host gneisses indicate high-grade metamorphic events at ca. 458–446 Ma and ca. 426 Maduring the Caledonian orogenic cycle.The presence of early Neoproterozoic silici clastic sedimentation and deformation in the Moine and equivalent successions around the North Atlantic and their absence along strike in eastern North America reflect contrasting Laurentian paleogeography during the breakup of Rodinia. The North Atlantic realm occupied an external location on the margin of Laurentia, and this region acted as a locus for accumulation of detritus (Moine Supergroup and equivalents) derived from the Grenville-Sveconorwegian orogenic welt, which developed as a consequence of collisional assembly of Rodinia. Neoproterozoic orogenic activity corresponds with theinferred development of convergent platemargin activity along the periphery of the supercontinent. In contrast in eastern North America, which lay within the internal parts of Rodinia, sedimentation did not commence until the mid-Neoproterozoic (ca. 760 Ma) during initial stages of supercontinent fragmentation. In the North Atlantic region, this time frame corresponds to a second pulse of extension represented by units such as the Dalradian Supergroup, which unconformably overlies the predeformed Moine succession

Estimation of speciated and total mercury dry deposition at monitoring locations in eastern and central North America

Dry deposition of speciated mercury, i.e., gaseous oxidized mercury (GOM), particulate-bound mercury (PBM), and gaseous elemental mercury (GEM), was estimated for the year 2008–2009 at 19 monitoring locations in eastern and central North America. Dry deposition estimates were obtained by combining monitored two- to four-hourly speciated ambient concentrations with modeled hourly dry deposition velocities (&lt;i&gt;V&lt;/i&gt;&lt;sub&gt;d&lt;/sub&gt;) calculated using forecasted meteorology. Annual dry deposition of GOM+PBM was estimated to be in the range of 0.4 to 8.1 μg m&lt;sup&gt;−2&lt;/sup&gt; at these locations with GOM deposition being mostly five to ten times higher than PBM deposition, due to their different modeled &lt;i&gt;V&lt;/i&gt;&lt;sub&gt;d&lt;/sub&gt; values. Net annual GEM dry deposition was estimated to be in the range of 5 to 26 μg m&lt;sup&gt;−2&lt;/sup&gt; at 18 sites and 33 μg m&lt;sup&gt;−2&lt;/sup&gt; at one site. The estimated dry deposition agrees very well with limited surrogate-surface dry deposition measurements of GOM and PBM, and also agrees with litterfall mercury measurements conducted at multiple locations in eastern and central North America. This study suggests that GEM contributes much more than GOM+PBM to the total dry deposition at the majority of the sites considered here; the only exception is at locations close to significant point sources where GEM and GOM+PBM contribute equally to the total dry deposition. The relative magnitude of the speciated dry deposition and their good comparisons with litterfall deposition suggest that mercury in litterfall originates primarily from GEM, which is consistent with the limited number of previous field studies. The study also supports previous analyses suggesting that total dry deposition of mercury is equal to, if not more important than, wet deposition of mercury on a regional scale in eastern North America

Editorial : Special issue on the 13th international workshop on the physics of compressible turbulent mixing

The study of compressible turbulent mixing associated with Richtmyer-Meshkov (RM), Rayleigh-Taylor (RT), and Kelvin-Helmholtz (KH) instabilities is motivated by diverse applications in science and engineering, including supersonic combustion, detonation, instability of collapsing gas bubbles, stratified flows in geophysical applications, chemical engineering, inertial confinement fusion (ICF), supernovae, and molecular clouds. Further, the interaction of shock waves with materials is also of interest in biomedical applications, such as fragmentation of cancer cells during shockwave chemotherapy and cavitation damage to human tissues during lithotripsy. In many of these applications, the Reynolds number is very high and the instabilities rapidly lead to turbulent mixing. In the case of ICF, which is regarded as a promising approach to controlled thermonuclear fusion: (1) these instabilities lead to the growth of perturbations on the interfaces within the capsules; (2) perturbations grow into the nonlinear regime by mode coupling and eventually cause mixing of materials; and (3) material mixing inhibits thermonuclear burning of the fuel