Efficient sorting of free electron orbital angular momentum

We propose a method for sorting electrons by orbital angular momentum (OAM). Several methods now exist to prepare electron wavefunctions in OAM states, but no technique has been developed for efficient, parallel measurement of pure and mixed electron OAM states. The proposed technique draws inspiration from the recent demonstration of the sorting of OAM through modal transformation. We show that the same transformation can be performed on electrons with electrostatic optical elements. Specifically, we show that a charged needle and an array of electrodes perform the transformation and phase correction necessary to sort OAM states. This device may enable the analysis of the spatial mode distribution of inelastically scattered electrons

Probing Light Atoms at Sub-nanometer Resolution: Realization of Scanning Transmission Electron Microscope Holography

Atomic resolution imaging in transmission electron microscopy (TEM) and scanning TEM (STEM) of light elements in electron-transparent materials has long been a challenge. Biomolecular materials, for example, are rapidly altered when illuminated with electrons. These issues have driven the development of TEM and STEM techniques that enable the structural analysis of electron beam-sensitive and weakly scattering nano-materials. Here, we demonstrate such a technique, STEM holography, capable of absolute phase and amplitude object wave measurement with respect to a vacuum reference wave. We use an amplitude-dividing nanofabricated grating to prepare multiple spatially separated electron diffraction probe beams focused at the sample plane, such that one beam transmits through the specimen while the others pass through vacuum. We raster-scan the diffracted probes over the region of interest. We configure the post specimen imaging system of the microscope to diffraction mode, overlapping the probes to form an interference pattern at the detector. Using a fast-readout, direct electron detector, we record and analyze the interference fringes at each position in a 2D raster scan to reconstruct the complex transfer function of the specimen, t(x). We apply this technique to image a standard target specimen consisting of gold nanoparticles on a thin amorphous carbon substrate, and demonstrate 2.4 angstrom resolution phase images. We find that STEM holography offers higher phase-contrast of the amorphous material while maintaining Au atomic lattice resolution when compared with high angle annular dark field STEM.Comment: 9 pages, 5 figures in main text, 1 supplemental figure in the appendi

Interpretable and efficient contrast in scanning transmission electron microscopy with a diffraction grating beamsplitter

Efficient imaging of biomolecules, 2D materials and electromagnetic fields depends on retrieval of the phase of transmitted electrons. We demonstrate a method to measure phase in a scanning transmission electron microscope using a nanofabricated diffraction grating to produce multiple probe beams. The measured phase is more interpretable than phase-contrast scanning transmission electron microscopy techniques without an off-axis reference wave, and the resolution could surpass that of off-axis electron holography. We apply the technique to image nanoparticles, carbon sub- strates and electric fields. The contrast observed in experiments agrees well with contrast predicted in simulations

Rural Land Market Data Report:Analysis of land sales data and proposals for improving future reporting of land market transactions A report to the Scottish Land Commission

This presents the findings of the second stage of a two-stage research project commissioned by the Scottish Land Commission, on improving reporting of land market transactions in Scotland. The first stage report aimed to identify current trends within Scotland’s rural land market to provide an up-to-date picture of buyer and seller motivations, with a specific focus on understanding how increased demand for natural capital investment is driving activity in the land market. The second phase of work set out in this report, undertook data collation on land sales from Registers of Scotland and incorporated supplementary data from Strutt and Parker, to develop a quantitative assessment of land market activity and land values in Scotland (for Scottish farmland, forestry and estates markets) for the 2020-2021 period. Additionally, this Phase 2 report identifies challenges for longer term land market assessment and sets out options for future collation of quantitative and qualitative data and reporting on land market activity.The methodology used in this report incorporated three main components: i) collation and analysis of Registers of Scotland land values data; ii) consultation with land agents to obtain additional data on land sales/acquisitions; and iii) data synthesis and developing proposals for a long-term approach to assessing rural land market activity. The final analysis was based primarily on collation and analysis of data from Registers of Scotland and data provided by our project partners Strutt and Parker. The collation of data on land sales from individual land agencies in Scotland was largely unsuccessful, due primarily to agent concerns around client confidentiality, the perceived commercial value of land sales data and the commercial sensitivity of pricing information, particularly for off-market sales. The final approach developed here has been designed to be repeated or adapted for future land market assessments, to facilitate increased transparency in the rural land market and identify longer term trends in market activity and key drivers for land sales and acquisitions.Data collated from Registers of Scotland (RoS) was reduced and focused by excluding registration information and related cadastral (title) parcels information below 25 hectares and not in rural areas and selecting specific data categories within the Registers of Scotland dataset for further interrogation (including the forestry, land and agriculture classifications). All collated RoS data was cross-checked against two additional databases provided by Strutt and Parker on estate sales and farm sales in 2020 and 2021, with the final analysis related primarily to sales which were identifiable within the Registers of Scotland data with the exception of the estates dataset, which used a hybrid approach to incorporate some area and sales price data from the Strutt and Parker estates data.This combined data collation and reduction process resulted in final datasets being created for farmland, forestry and estate sales in Scotland, which included a minority of listings (unknowns) where area was not identifiable but where a consideration (sale price) was shown in the RoS data. There are several important caveats and related challenges to undertaking market assessments based on RoS data and/or merging RoS data with land sales information from other sources. Key specific caveats include: i) the difference in timescales between completion of registrations and land sales actually occurring, which can result in a RoS based analysis excluding more recent sales due to pending registrations; ii) the difficulty in assigning area (hectarage) to all land sales due to delays in cadastral parcel mapping which has resulted in some recoded registrations being excluded from any area based analysis; iii) and a lack of specific additional data relating to forest/farm type and buyer type and missing sales price information in some cases which has resulted in the 2021 estates market assessment in particular, being a considerable underestimate in terms of total market value and average estate pric

International Case Studies on Demographic Change in Remote Rural Areas: What can Scotland learn from elsewhere?

This working paper is an output of a project funded by the Scottish Government’s Rural andEnvironment Science and Analytical Services (RESAS) division’s 2016-2020 StrategicResearch Programme1. Specifically, this work has been carried out under ResearchDeliverable 3.4.1 ‘Demographic Change in Remote Areas’. The underpinning researchquestion addressed by this project is “How do changes in the population of remote rural areasof Scotland affect the social, economic and ecological resilience of these areas?” Previousworking papers have specifically addressed the definition of sparsely populated areas and thedemographic and economic structures and policy approaches in these areas (Copus andHopkins; 2017 and Mc Morran; Copus and Atterton 2017). This paper focuses on the selection of a small number of case study regions from outwith Scotland, which have comparabledegrees of remoteness and sparsity (or “population potential”), with the aim of investigatingthese cases as potential sources of good practice ideas and alternative policy approaches intackling demographic stagnation or decline which are of relevance to Scotland