Almost Dark Galaxies: The Search for Optical Counterparts

Presented in this paper are results from neutral hydrogen (HI) imaging and analysis of the Almost Dark galaxies AGC 219533, AGC 227982, and AGC 268363 using new, higher resolution observations from the Very Large Array (VLA). Selected from the ALFALFA survey, Almost Dark galaxies possess significant HI reservoirs but, when the HI data is compared to survey-depth ground-based optical imaging, their optical stellar counterparts have extremely low surface brightnesses. AGC 219533 is one such object. The other two sources, AGC 227982 and AGC 26833, were candidate dark galaxies, as no stellar counterpart was identified in initial ALFALFA optical matching, and as such they possessed some of the most extreme levels of suppressed star formation amongst the isolated sources in the ALFALFA catalog. The new multiconfiguration, high angular (~20 ) and spectral (1.7 km/s) resolution HI observations presented here have produced spatially resolved column density and velocity distribution moment maps where the HI has been localized. HI masses are derived from VLA flux integral values and ALFALFA distance estimates, and are consistent with those derived from ALFALFA fluxes. Comparison of our resolved HI observations to Sloan Digitized Sky Survey (SDSS) optical images reveals previously unknown optical components for AGC 227982 and AGC 268363, and confirms the association with a very low surface brightness stellar counterpart for AGC 219533. These new results eliminate the three galaxies\u27 candidacy as dark galaxies

Use of rare earth oxides as tracers to identify sediment source areas for agricultural hillslopes

Understanding sediment sources is essential to enable more effective targeting of in-field mitigation approaches to reduce diffuse pollution from agricultural land. In this paper we report on the application of rare earth element oxides to arable soils at hillslope scale in order to determine sediment source areas and their relative importance, using a non-intrusive method of surface spraying. Runoff, sediments and rare earth elements lost from four arable hillslope lengths at a site in the UK with clay soils were monitored from three rainfall events after tracer application. Measured erosion rates were low, reflecting the typical event conditions occurring at the site, and less than 1% of the applied REO tracers were recovered, which is consistent with the results of comparable studies. Tracer recovery at the base of the hillslope was able to indicate the relative importance of different hillslope sediment source areas, which were found to be consistent between events. The principal source of eroded sediments was the upslope area, implying that the wheel tracks were principally conduits for sediment transport, and not highly active sites of erosion. Mitigation treatments for sediment losses from arable hillslopes should therefore focus on methodologies for trapping mobile sediments within wheel track areas through increasing surface roughness or reducing the connectivity of sediment transport processes

Sensitivity analysis of EUROSEM using Monte Carlo simulation II::the effect of rills and rock fragments

A sensitivity analysis of the surface and catchment characteristics in the European soil erosion model (EUROSEM) was carried out with special emphasis on rills and rock fragment cover. The analysis focused on the use of Monte Carlo simulation but was supplemented by a simple sensitivity analysis where input variables were increased and decreased by 10%. The study showed that rock fragments have a significant effect upon the static output parameters of total runoff, peak flow rate, total soil loss and peak sediment discharge, but with a high coefficient of variation. The same applied to the average hydrographs and sedigraphs although the peak of the graphs was associated with a low coefficient of variation. On average, however, the model was able to simulate the effect of rock fragment cover quite well. The sensitivity analysis through the Monte Carlo simulation showed that the model is particularly sensitive to changes in parameters describing rills and the length of the plane when no rock fragments are simulated but that the model also is sensitive to changes in the fraction of non-erodible material and interrill slope when rock fragments were embedded in the topsoil. For rock fragments resting on the surface, changes in parameter values did not affect model output significantly. The simple sensitivity analysis supported the findings from the Monte Carlo simulation and illustrates the importance when choosing input parameters to describe both rills and rock fragment cover when modelling with EUROSEM

Spatial and Temporal Variations in Active Layer Thawing and Their Implication on Runoff Generation in Peat-Covered Permafrost Terrain

The distribution of frost table depths on a peat-covered permafrost slope was examined in a discontinuous permafrost region in northern Canada over 4 consecutive years at a variety of spatial scales, to elucidate the role of active layer development on runoff generation. Frost table depths were highly variable over relatively short distances (0.25–1 m), and the spatial variability was strongly correlated to soil moisture distribution, which was partly influenced by lateral flow converging to frost table depressions. On an interannual basis, thaw rates were temporally correlated to air temperature and the amount of precipitation input. Simple simulations show that lateral subsurface flow is governed by the frost table topography having spatially variable storage that has to be filled before water can spill over to generate flow downslope, in a similar manner that bedrock topography controls subsurface flow. However, unlike the bedrock surface, the frost table is variable with time and strongly influenced by the heat transfer involving water. Therefore, it is important to understand the feedback between thawing and subsurface water flow and to properly represent the feedback in hydrological models of permafrost regions

Thioglycolic acid on the gold (111) surface and Raman vibrational spectra

The interaction of thioglycolic acid with the Au(111) surface is investigaged, and it is found that at the low coverage the molecule lies down on the substrate. If the mercaptan-hydrogen atom is eliminated, the resulting SCH_2COOH molecule is randomly oriented on the surface. If the carboxylic acid group in the HSCH_2COOH molecule is deprotonated instead, the HSCH_2COO^ molecule lies down on the surface. However, when the mercaptan-hydrogen atom in the HSCH_2COO^- molecule is removed, the resulting SCH_2COO^- molecule rises up to a certain level on the substrate. The calculated Raman vibrational spectra decipher which compounds and atomic displacements contribute to the corresponding frequencies. We thus propose a consistent mechanism for the deposition of thioglycolic acid on the Au(111) surface.Comment: 18 pages, 5 figures, submitted to J. Chem. Phy

Ship Collision Mitigation: Redesign of an Oil Tanker Sideshell

Structural design has been shown to be an effective tool for reducing collision damage and cargo spill of a struck oil tanker given a collision. This paper explores the structural redesign of a double-hull oil tanker side-shell in order to improve its collision performance with respect to hull rupture, damaged area, and oil-outflow. In particular, the sideshell plate stiffening arrangement and transverse web frames are redesigned, with weight and structural capacity as design constraints. Explicit-dynamics numerical models using LSDYNA show that reducing the structural rigidity of the tanker’s side-shell, while maintaining the same plate stiffening steel weight may: increase the efficiency of the side-shell in converting kinetic collision energy into elastic strain energy; reduce the longitudinal and overall damaged areas; and ”compartmentalize” the damage so that residual stresses decrease quickly with radial distance from the point of impact

Roles of Capabilities and Leader Characteristics in SME Digital Innovation

Digital technology (viewed as the combination of information, computing, communication, and connectivity technology) is impacting on the marketplaces that SMEs operate in. Yet, little is understood about how these businesses are adapting to, and adopting, digital technologies and creating digital innovation. Technology can be viewed as an opportunity for SMEs through which to engage in competitive behaviour, cost reduction, audience extension and intelligence gathering. European Commission recognises the SMEs form the backbone of the European economy Qualitative data were gathered from 45 interviews with SME leaders across four European countries and 5 industry sectors. This paper reports on the findings from a research project investigating digital preparedness of European SMEs and specifically the characteristics and capabilities of SME leaders in adopting digital innovation. Insight is outlined through the scope of the research which integrates different countries, sizes of SMEs and industry sectors to provide an holistic view of European SME leader perceptions. General consensus was evident as to the characteristics and capabilities required to create digital innovation in a competitive environment and a tentative framework has been created. This paper contributes to scholarship by providing a more comprehensive view of current European perceptions by SME practitioners concerning the profile of an SME leader undertaking digital innovation. Management implications include that any evaluation of SME digital innovation preparedness should look beyond capabilities and skills sets and include intangible aspects of character such as leaders’ attitudes towards technologies.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech