Sesame-Style Decomposition of KS-DFT Molecular Dynamics for Direct Interrogation of Nuclear Models

A common paradigm used in the construction of equations of state is to decompose the thermodynamics into a superposition of three terms: a static-lattice cold curve, a contribution from the thermal motion of the nuclei, and a contribution from the thermal excitation of the electrons. While statistical mechanical models for crystals provide tractable framework for the nuclear contribution in the solid phase, much less is understood about the nuclear contribution above the melt temperature ($C_v^{(\text{nuc})}\approx 3R$) and how it should transition to the high-temperature limit ($C_v^{(\text{nuc})} \sim \frac{3}{2}R$). In this work, we describe an algorithm for extracting both the thermal nuclear and thermal electronic contributions from quantum molecular dynamics (QMD). We then use the VASP QMD package to probe thermal nuclear behavior of liquid aluminum at normal density to compare the results to semi-empirical models -- the Johnson generic model, the Chisolm high-temperature liquid model, and the CRIS model.Comment: 6 pages, 4 figures, APS Shock Compression of Condensed Matter Conference Proceedings 201

A strategic framework to support the implementation of citizen science for environmental monitoring. Final report to SEPA

In this report we provide a decision framework that can be used to guide whether and when to use a citizen science approach for environmental monitoring. Before using the decision framework we recommend that five precursors to a citizen science approach are considered

Choosing and using citizen science: a guide to when and how to use citizen science to monitor biodiversity and the environment

Here we aim to provide guidance to support people considering using a citizen science approach, especially (but not necessarily restricted to) monitoring biodiversity and the environment in the UK. It will help you decide whether citizen science is likely to be useful, and it will help you decide which broad approach to citizen science is most suitable for your question or activity. This guide does not cover the practical detail of developing a citizen science project. That information is provided in the ‘Guide to Citizen Science’ (Tweddle et al., 2012)

The structure of epitaxial V2O3 films and their surfaces : a medium energy ion scattering study

Medium energy ion scattering, using 100 keV H+ incident ions, has been used to investigate the growth of epitaxial films, up to thicknesses of ~200 Å, of V2O3 on both Pd(111) and Au(111). Scattered-ion energy spectra provide a measure of the average film thickness and the variations in this thickness, and show that, with suitable annealing, the crystalline quality is good. Plots of the scattering yield as a function of scattering angle, so-called blocking curves, have been measured for two different incidence directions and have been used to determine the surface structure. Specifically, scattering simulations for a range of different model structures show poor agreement with experiment for half-metal (….V’O3V) and vanadyl (….V’O3V=O) terminations, with and without surface interlayer relaxations. However, good agreement with experiment is found for the modified oxygen-termination structure, first proposed by Kresse et al., in which a subsurface V half-metal layer is moved up into the outermost V buckled metal layer to produce a VO2 overlayer on the underlying V2O3, with an associated layer structure of ….O3VV’’V’O3

Finding the trigger to Iapetus' odd global albedo pattern: Dynamics of dust from Saturn's irregular satellites

The leading face of Saturn's moon Iapetus, Cassini Regio, has an albedo only one tenth that on its trailing side. The origin of this enigmatic dichotomy has been debated for over forty years, but with new data, a clearer picture is emerging. Motivated by Cassini radar and imaging observations, we investigate Soter's model of dark exogenous dust striking an originally brighter Iapetus by modeling the dynamics of the dark dust from the ring of the exterior retrograde satellite Phoebe under the relevant perturbations. In particular, we study the particles' probabilities of striking Iapetus, as well as their expected spatial distribution on the Iapetian surface. We find that, of the long-lived particles (greater than about 5 microns), most particle sizes (greater than about 10 microns) are virtually certain to strike Iapetus, and their calculated distribution on the surface matches up well with Cassini Regio's extent in its longitudinal span. The satellite's polar regions are observed to be bright, presumably because ice is deposited there. Thus, in the latitudinal direction we estimate polar dust deposition rates to help constrain models of thermal migration invoked to explain the bright poles (Spencer & Denk 2010). We also analyze dust originating from other irregular outer moons, determining that a significant fraction of that material will eventually coat Iapetus--perhaps explaining why the spectrum of Iapetus' dark material differs somewhat from that of Phoebe. Finally we track the dust particles that do not strike Iapetus, and find that most land on Titan, with a smaller fraction hitting Hyperion. As has been previously conjectured, such exogenous dust, coupled with Hyperion's chaotic rotation, could produce Hyperion's roughly isotropic, moderate-albedo surface.Comment: Accepted for publication in Icaru

The AllWISE Motion Survey, Part 2

We use the AllWISE Data Release to continue our search for WISE-detected motions. In this paper, we publish another 27,846 motion objects, bringing the total number to 48,000 when objects found during our original AllWISE motion survey are included. We use this list, along with the lists of confirmed WISE-based motion objects from the recent papers by Luhman and by Schneider et al. and candidate motion objects from the recent paper by Gagne et al. to search for widely separated, common-proper-motion systems. We identify 1,039 such candidate systems. All 48,000 objects are further analyzed using color-color and color-mag plots to provide possible characterizations prior to spectroscopic follow-up. We present spectra of 172 of these, supplemented with new spectra of 23 comparison objects from the literature, and provide classifications and physical interpretations of interesting sources. Highlights include: (1) the identification of three G/K dwarfs that can be used as standard candles to study clumpiness and grain size in nearby molecular clouds because these objects are currently moving behind the clouds, (2) the confirmation/discovery of several M, L, and T dwarfs and one white dwarf whose spectrophotometric distance estimates place them 5-20 pc from the Sun, (3) the suggestion that the Na 'D' line be used as a diagnostic tool for interpreting and classifying metal-poor late-M and L dwarfs, (4) the recognition of a triple system including a carbon dwarf and late-M subdwarf, for which model fits of the late-M subdwarf (giving [Fe/H] ~ -1.0) provide a measured metallicity for the carbon star, and (5) a possible 24-pc-distant K5 dwarf + peculiar red L5 system with an apparent physical separation of 0.1 pc.Comment: 62 pages with 80 figures, accepted for publication in The Astrophysical Journal Supplement Series, 23 Mar 2016; second version fixes a few small typos and corrects the footnotes for Table

Surface and interface structural studies using medium energy ion scattering

The technique of medium energy ion scattering (MEIS) can be used to elucidate the structural details of surfaces, both in general terms and in a more qualitative manner, in order to help solve a number of outstanding uncertainties relating to the structures of a number of surface systems. MEIS, involving the back-scattering of light ions from a material of interest, in this case 100 keV H+ ions from adsorbate covered single crystal metal surfaces, can potentially be a powerful tool for obtaining either depth-dependent compositional information or quantitative structural details. MEIS has been used to study the surface relaxations at the Cu(410)-O stepped surface. The results have been compared to a number of models favoured by previous studies, and an optimisation of the structural parameters associated with the outermost Cu atoms was undertaken so as to determine the positions of these atoms to a reasonable degree of precision. In this thesis, MEIS has also been used to probe the surface reconstructions triggered by the adsorption of the methylthiolate species on the Cu(100), Au(111) and Pd(111) surfaces. Methylthiolate is derived from the n-alkylthiol molecule methylth- iol, the simplest molecule of a species which ubiquitously form so called self-assembled monolayers (SAMs) on single crystal metal surfaces. In the case of Cu(100), our study confirms the existence of a radial lateral distortion of the outermost Cu layer, and we quantify this distortion. For Au(111), two competing structural models for the methylth- iolate overlayer have been proposed, namely the Au-adatom-monothiolate (AAM) and Au-adatom-dithiolate (AAD). MEIS has been used to compare these two models, and we find in favour of the AAD model. Additionally, evidence has been found for a significant reconstruction of the Pd(111) surface triggered by adsorption of methylthiolate. We have carried out a MEIS investigation of the (3×2)-alaninate phase formed by adsorption of the chiral molecule alanine on Cu(110). Evidence is found for a small degree of lateral surface distortion

Evaluation of early and late presentation of patients with ocular mucous membrane pemphigoid to two major tertiary referral hospitals in the United Kingdom

PURPOSE: Ocular mucous membrane pemphigoid (OcMMP) is a sight-threatening autoimmune disease in which referral to specialists units for further management is a common practise. This study aims to describe referral patterns, disease phenotype and management strategies in patients who present with either early or established disease to two large tertiary care hospitals in the United Kingdom.\ud \ud PATIENTS AND METHODS: In all, 54 consecutive patients with a documented history of OcMMP were followed for 24 months. Two groups were defined: (i) early-onset disease (EOD:<3 years, n=26, 51 eyes) and (ii) established disease (EstD:>5 years, n=24, 48 eyes). Data were captured at first clinic visit, and at 12 and 24 months follow-up. Information regarding duration, activity and stage of disease, visual acuity (VA), therapeutic strategies and clinical outcome were analysed.\ud \ud RESULTS: Patients with EOD were younger and had more severe conjunctival inflammation (76% of inflamed eyes) than the EstD group, who had poorer VA (26.7%=VA<3/60, P<0.01) and more advanced disease. Although 40% of patients were on existing immunosuppression, 48% required initiation or switch to more potent immunotherapy. In all, 28% (14) were referred back to the originating hospitals for continued care. Although inflammation had resolved in 78% (60/77) at 12 months, persistence of inflammation and progression did not differ between the two phenotypes. Importantly, 42% demonstrated disease progression in the absence of clinically detectable inflammation.\ud \ud CONCLUSIONS: These data highlight that irrespective of OcMMP phenotype, initiation or escalation of potent immunosuppression is required at tertiary hospitals. Moreover, the conjunctival scarring progresses even when the eye remains clinically quiescent. Early referral to tertiary centres is recommended to optimise immunosuppression and limit long-term ocular damage.\ud \u

Clumped isotope evidence for episodic, rapid flow of fluids in a mineralized fault system in the Peak District, UK

We have used clumped isotope thermometry to study a fault-hosted hydrothermal calcite vein associated with the Mississippi Valley Type (MVT) mineralization on the Derbyshire Platform in the southern Pennines, UK. This is the first published dataset obtained using a new mass spectrometer, MIRA, optimized for clumped isotope analysis and an associated clumped isotope-temperature calibration. We analysed multiple generations of vein growth at high spatial resolution in two transects across the vein. The vein grew episodically at temperatures between 40 and 100°C. We interpret each episode of growth as being associated with an increasing flux of formation waters from deep sedimentary basins next to the mineralized platform and an accompanying increase in the precipitation temperatures. Heat is conserved in the fluid as it ascends along the fault surface and, thus, flow must have been fast and restricted to short-lived pulses. The flux could have been driven by high pore pressures associated with rapid sedimentation, hydrocarbon generation and diagenesis in the basinal facies of the Visean Bowland-Hodder group. Natural hydraulic fracturing of shale units and failure of capillary seals, possibly triggered by uplift, allowed the release of fluids into aquifers within the sediment pile. The transmission of high pore fluid pressures from the shales to the fault zone, aided by the compressibility of the gas phase in two-phase pore fluids, may have resulted in fault rupture, accompanied by enhanced fracture permeability and rapid fluid flow. Vein growth ceased as pore pressures dissipated. Such behaviour is closely related to a seismic valve type model for mineralization