5,210 research outputs found
Ecological survey of the native pinewoods of Scotland 1971
In 1971, a comprehensive ecological survey of the native pinewoods of Scotland was carried out by the Institute of Terrestrial Ecology. The survey was initiated as a consequence of growing concern about the status of the pinewood resource. Since the Twentieth Century, this unique habitat is widely recognised, not only by ecologists for its inherent biodiversity, but also by the general public for its cultural and amenity value. The survey, utilising demonstrably repeatable methods, collected information on ground flora, soils, forest structure and also general site information from the major 27 sites of the 35 sites identified as truly native pinewoods in Scotland. The results from the survey prompted the organisation of an International Symposium in 1975, which set the conservation agenda for the Old Caledonian Pinewoods. The data collected during the 1971 survey are now publicly available via the following DOI: http://doi.org/10/7xb (Habitat, vegetation, tree and soil data from Native Pinewoods in Scotland, 1971). Although the data are now 44 years old, the repeatable methods will allow for a resurvey to take place, in order to assess changes in the vegetation, habitats and tree composition in statistically robust manner
Survey of the terrestrial habitats and vegetation of Shetland, 1974 – a framework for long-term ecological monitoring
A survey of the natural environment was undertaken in Shetland in 1974, after concern was expressed that large-scale development from the new oil industry could threaten the natural features of the islands. A framework was constructed by the Institute of Terrestrial Ecology on which to select samples for the survey. The vegetation and habitat data that were collected, along with the sampling framework, have recently been made public via the following doi:10.5285/06fc0b8c-cc4a-4ea8-b4be-f8bd7ee25342 (Terrestrial habitat, vegetation and soil data from Shetland, 1974) and doi:10.5285/f1b3179e-b446-473d-a5fb-4166668da146 (Land Classification of Shetland 1974). In addition to providing valuable information about the state of the natural environment of Shetland, the repeatable and statistically robust methods developed in the survey were used to underpin the Countryside Survey, Great Britain's national long-term integrated environmental monitoring programme. The demonstration of the effectiveness of the methodology indicates that a repeat of the Shetland survey would yield statistics about ecological changes in the islands, such as those arising from the impacts of the oil industry, a range of socio-economic impacts, and perhaps climate change. Currently no such figures are available, although there is much information on the sociological impacts, as well as changes in agriculture
Design and characterisation of titanium nitride sub-arrays of kinetic inductance detectors for passive terahertz imaging
We report on the investigation of titanium nitride (TiN) thin films deposited via atomic layer deposition (ALD) for microwave kinetic inductance detectors (MKID). Using our in-house ALD process, we have grown a sequence of TiN thin films (thickness 15, 30, 60 nm). The films have been characterised in terms of superconducting transition temperature Tc , sheet resistance Rs and microstructure. We have fabricated test resonator structures and characterised them at a temperature of 300 mK. At 350 GHz, we report an optical noise equivalent power NEPopt≈2.3×10−15 W/√Hz , which is promising for passive terahertz imaging applications
Density Range of Compression-Molded Polypropylene-Wood Composites
Wood and polypropylene fibers were mixed together in various proportions and compression-molded to boards of various specific gravities. The full theoretical specific gravity range could not be obtained even when the boards were cooled in the press. Voids surrounding the wood fibers possibly were due to the shrinkage of the wood fiber following pressing. Bending and tension properties were influenced more by the compression of the wood fibers than by the percentage of wood fiber addition
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Characterization of a continuous feline mammary epithelial cell line susceptible to feline epitheliotropic viruses.
Mucosal epithelial cells are the primary targets for many common viral pathogens of cats. Viral infection of epithelia can damage or disrupt the epithelial barrier that protects underlying tissues. In vitro cell culture systems are an effective means to study how viruses infect and disrupt epithelial barriers, however no true continuous or immortalized feline epithelial cell culture lines are available. A continuous cell culture of feline mammary epithelial cells (FMEC UCD-04-2) that forms tight junctions with high transepithelial electrical resistance (>2000Omegacm(-1)) 3-4 days after reaching confluence was characterized. In addition, it was shown that FMECs are susceptible to infection with feline calicivirus (FCV), feline herpesvirus (FHV-1), feline coronavirus (FeCoV), and feline panleukopenia virus (FPV). These cells will be useful for studies of feline viral disease and for in vitro studies of feline epithelia
Photoionization of High Altitude Gas in a Supernova-Driven Turbulent Interstellar Medium
We investigate models for the photoionization of the widespread diffuse
ionized gas in galaxies. In particular we address the long standing question of
the penetration of Lyman continuum photons from sources close to the galactic
midplane to large heights in the galactic halo. We find that recent
hydrodynamical simulations of a supernova-driven interstellar medium have low
density paths and voids that allow for ionizing photons from midplane OB stars
to reach and ionize gas many kiloparsecs above the midplane. We find ionizing
fluxes throughout our simulation grids are larger than predicted by one
dimensional slab models, thus allowing for photoionization by O stars of low
altitude neutral clouds in the Galaxy that are also detected in Halpha. In
previous studies of such clouds the photoionization scenario had been rejected
and the Halpha had been attributed to enhanced cosmic ray ionization or
scattered light from midplane H II regions. We do find that the emission
measure distributions in our simulations are wider than those derived from
Halpha observations in the Milky Way. In addition, the horizontally averaged
height dependence of the gas density in the hydrodynamical models is lower than
inferred in the Galaxy. These discrepancies are likely due to the absence of
magnetic fields in the hydrodynamic simulations and we discuss how
magnetohydrodynamic effects may reconcile models and observations.
Nevertheless, we anticipate that the inclusion of magnetic fields in the
dynamical simulations will not alter our primary finding that midplane OB stars
are capable of producing high altitude diffuse ionized gas in a realistic
three-dimensional interstellar medium.Comment: ApJ accepted. 17 pages, 7 figure
Using Neutron Reflectometry to Discern the Structure of Fibrinogen Adsorption at the Stainless Steel/Aqueous Interface.
Neutron reflectometry has been successfully used to study adsorption on a stainless steel surface by means of depositing a thin steel film on silicon. The film was characterized using XPS (X-ray photoelectron spectroscopy), TOF-SIMS (time-of-flight secondary ion mass spectrometry), and GIXRD (grazing incidence X-ray diffraction), demonstrating the retention both of the austenitic phase and of the required composition for 316L stainless steel. The adsorption of fibrinogen from a physiologically-relevant solution onto the steel surface was studied using neutron reflectometry and QCM (quartz crystal microbalance) and compared to that on a deposited chromium oxide surface. It was found that the protein forms an irreversibly bound layer at low concentrations, with maximum protein concentration a distance of around 20 Ã… from the surface. Evidence for a further diffuse reversibly-bound layer forming at higher concentrations was also observed. Both the structure of the layer revealed by the neutron reflectometry data and the high water retention predicted by the QCM data suggest that there is a significant extent of protein unfolding upon adsorption. A lower extent of adsorption was seen on the chromium surfaces, although the adsorbed layer structures were similar, suggesting comparable adsorption mechanisms.M.H.W. is grateful to the Oppenheimer Trust for funding.This is the author accepted manuscript. The final version is available from the American Chemical Socitey via http://dx.doi.org/10.1021/acs.jpcb.6b0234
Fast calibrated additive quantile regression
We propose a novel framework for fitting additive quantile regression models,
which provides well calibrated inference about the conditional quantiles and
fast automatic estimation of the smoothing parameters, for model structures as
diverse as those usable with distributional GAMs, while maintaining equivalent
numerical efficiency and stability. The proposed methods are at once
statistically rigorous and computationally efficient, because they are based on
the general belief updating framework of Bissiri et al. (2016) to loss based
inference, but compute by adapting the stable fitting methods of Wood et al.
(2016). We show how the pinball loss is statistically suboptimal relative to a
novel smooth generalisation, which also gives access to fast estimation
methods. Further, we provide a novel calibration method for efficiently
selecting the 'learning rate' balancing the loss with the smoothing priors
during inference, thereby obtaining reliable quantile uncertainty estimates.
Our work was motivated by a probabilistic electricity load forecasting
application, used here to demonstrate the proposed approach. The methods
described here are implemented by the qgam R package, available on the
Comprehensive R Archive Network (CRAN)
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