1,099 research outputs found
Lime and Ice Project : an overview of the geology and geomorphology of part of the Hambleton and Howardian Hills for the North York Moors National Park Authority
This report provides an overview of the geology and landscape that characterises the Hambleton
Hills and part of the Howardian Hills that together comprise the North York Moors National
Park Authority (NYMNPA) ‘Lime and Ice’ project area. This outreach and community project is
centred on the Sutton Bank Visitor Centre and aims to inform and excite visitors about the
geology and landscape of this beautiful area. Underpinning an understanding of the natural
history and the development of the area is an appreciation of the geological evolution of the
Jurassic bedrock geology (‘lime’) and the impact of the last ice-age (‘ice’) that left a thin veneer
of overlying glacial deposits over part of the area. A 200 million year geological history that
records ancient shallow seas, rivers and deltas, major earth movements and the later impact of
major glaciations, especially the last ice-age, is brought to life here to illustrate the dynamic
Earth history and our more recent influence on the landscape.
The report covers the geographic scope of the ‘Lime and Ice’ Project area (Section 1) which
includes part of the North York Moors National Park, an Area of Outstanding Natural Beauty,
and the Coxwold-Gilling gap sandwiched between these designated areas. An overview of the
geomorphology of the area (Section 2) comprising the upland moors of the Hambletons Hills, the
low ground below the main escarpment and the rolling Howardian Hills sets the scene. The main
part of the report (Section 3) describes the geological history and resources of the Jurassic rocks
in the area in the context of the wider Cleveland (Yorkshire) Basin, with special reference to the
local outcrops and landscape features. This is followed by a description of the influence of the
last ice-age and subsequent post-glacial mass movement features that have sculpted and moulded
the landscape that we appreciate today. The later sections cover the major Earth movements that
have folded, faulted (displaced) and uplifted the rocks during the last 200 million years (Section
4) and the Section 5 provides an overview of our human exploitation of the natural geological
resources of the area.
A bibliography of source material and further reading is provided. Technical and/or geological
terms are highlighted by grey shading; these may require further explanation for the nonspecialist
in a Glossary depending on the knowledge of the intended audience and advice from
the NYMNPA
Semantic memory is impaired in both dementia with Lewy Bodies (DLB) and dementia of Alzheimer's type (DAT): a comparative neuropsychological study and literature review
OBJECTIVE---To test the hypothesis that semantic impairment is present in both patients with dementia with Lewy bodies (DLB) and those with dementia of Alzheimer's type (DAT).
METHODS---A comprehensive battery of neuropsychological tasks designed to assess semantic memory, visuoperceptual function, verbal fluency, and recognition memory was given to groups of patients with DLB (n=10), DAT (n=10) matched pairwise for age and mini mental state examination (MMSE), and age matched normal controls (n=15).
RESULTS---Both DLB and DAT groups exhibited impaired performance across the range of tasks designed to assess semantic memory. Whereas patients with DAT showed equivalent comprehension of written words and picture stimuli, patients with DLB demonstrated more severe semantic deficits for pictures than words. As in previous studies, patients with DLB but not those with DAT were found to have impaired visuoperceptual functioning. Letter and category fluency were equally reduced for the patients with DLB whereas performance on letter fluency was significantly better in the DAT group. Recognition memory for faces and words was impaired in both groups.
CONCLUSIONS---Semantic impairment is not limited to patients with DAT. Patients with DLB exhibit particular problems when required to access meaning from pictures that is most likely to arise from a combination of semantic and visuoperceptual impairments
A Comparison of Two Averaging Techniques with an Application to Growth Empirics
Empirical growth research faces a high degree of model uncertainty. Apart from the neoclassical growth model, many new (endogenous) growth models have been proposed. This causes a lack of robustness of the parameter estimates and makes the determination of the key determinants of growth hazardous. The current paper deals with the fundamental issue of parameter estimation under model uncertainty, and compares the performance of various model averaging techniques. In particular, it contrasts Bayesian model averaging (BMA) — currently one of the standard methods used in growth empirics — with weighted-average least squares (WALS), a method that has not previously been applied in this context.
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Beryllium and lithium resource requirements for solid blanket designs for fusion reactors
Does Immigration Impact Institutions?
This paper empirically examines how immigration impacts a nation's policies and institutions and finds no evidence of negative and some evidence of positive impacts in institutional quality as a result of immigration
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Analysis of steady-state and pulsed operating regimes for controlled thermonuclear reactors with very large power ratings
The operating regimes of large CTR's are identified and examined for cases of steady-state and pulsed operation. Several technological benefits of these large reactors are determined: (1) low maximum magnetic field strength requirements (25 to 50 percent less than for 5000 MW(th) reactors), (2) high n tau products (10 to 10 sec/cm) with associated high burn- up fractions (10 to 50 percent), (3) relatively little problem with impurity build-up, and (4) long confinement times (50 to 500 seconds). The advantages of pulsed operation are also discussed: (1) smaller problem with impurities than in the steady-state case, (2) alleviation of any possible fueling difficulties, and (3) no problem with control of temperature in the pulsed reactor based on a simple control function model incorporating a finite delay time. (auth
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Steady-state plasma and reactor parameters for elliptical cross section tokamaks with very large power ratings
In previous studies only circular cross section reactor plasmas were considered. The purpose of this research is to examine the effects of elliptical plasma cross sections. Several technological benefits have been determined. Maximum magnetic field strength requirements are 30 to 65 percent less than for 5000 MW (th) reactors and may be as much as 40 percent less than for circular cross section reactors of comparable size. Very large n tau values are found (10 to 10 sec/cm), which produce large burn-up fractions (15 to 60 percent). There is relatively little problem with impurity build-up. Long confinement times (60 to 500 seconds) are found. Finally, the elliptical cross section reactors exhibit a major toroidal radius reduction of as large as 30 percent over circular reactors operating at comparable power levels. (auth
Gill net catch composition and catch per unit effort in Flag Boshielo Dam, Limpopo Province, South Africa
Gill net surveys were conducted in 2013 to determine species composition and fisheries potential of Flag Boshielo Dam. Species contributing the most towards total biomass were Labeo rosae (40%), Oreochromis mossambicus (15%), Schilbe intermedius (10%) and Labeobarbus marequensis (9.8%). Catch per unit effort for gill nets set at night (4.4 ± 0.6 kg·100 m-net−1·hr−1) was significantly higher (P < 0.05) than for those set during the day (0.9 ± 0.1 kg·100 m-net−1·hr−1). Total fish biomass captured in 30, 50, 70, 90 and 110 mm mesh sized nets was 3.1, 31.5, 43.5, 23.5 and 16.1 kg, respectively. Catch in gillnets with mesh sizes ≥ 70 mm was dominated by L. rosae comprising 60% of the catch in the 70 mm mesh; L. rosae (40%) and O. mossambicus (36%) in the 90 mm mesh; and O. mossambicus (40%) and Clarias gariepinus (40%) in the 110 mm mesh. If a small-scale fishery were to be initiated, it is recommended that mesh sizes should exceed 70 mm and that further research on the biology and ecology of the main target species and of the current utilisation of the fishery be conducted to guide sustainable utilisation.Keywords: Arabie Dam, CPUE, fish composition, net selectivity, inland fisherie
First report of oomycetes associated with the invasive tree Parkinsonia aculeata (Family: Fabaceae)
Phytophthora species have caused the decline and dieback of multiple tree species in Australia and around the world. Dieback in invasive trees in Australia has been observed for decades, motivating research into the potential causes of dieback to be used for biological control of these invasive species. Despite wide-ranging and ongoing research into invasive plant dieback, Phytophthora species have been largely ignored as potential causal agents of dieback, with the focus more on latent fungal pathogens living as endophytes. We conducted the first survey of Phytophthora and other oomycetes to determine their association with dieback of the invasive tree, Parkinsonia aculeata L. (Fabaceae). Using zoospore baiting, we recovered 37 oomycete isolates from roots and soil of healthy and dieback-affected P. aculeata in Kununurra, Western Australia and Charters Towers, Queensland. Using molecular taxonomy, we identified ten unique oomycete taxa, predominantly composed of Phytophthora palmivora, Ph. nicotianae and Phytopythium vexans. Parkinsonia dieback occurs across multiple climatic zones including those experiencing severe drought. We recovered fewer oomycete isolates from soil and roots in drought-affected Charters Towers than Kununurra, which had experienced recent rainfall. This may be because oomycetes require soil moisture for the dispersal of zoospores. None of the genotypes identified were consistently isolated from dieback-affected trees suggesting that any association with parkinsonia dieback may be localised. More extensive surveys and pathogenicity screenings of isolated oomycetes are required to evaluate their role in the parkinsonia dieback phenomenon
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Target designs for the Brookhaven National Laboratory 5-MW pulsed spallation neutron source
A feasibility study of a compact high power density target for a spallation neutron source was under-taken. The target arrangement consists primarily of heavy metal, with appropriate cooling passages. A high intensity proton beam of intermediate energy is directed at the target, where it interacts with the heavy metal nuclei. The subsequent spallation reactions produce several neutrons per proton resulting in an intense neutron source. The proton beam is assumed to havean energy of 5 MW, and to be cyclic with a repetition rate of 10Hz and 50Hz. The study was divided into two broad sections. First, an analysis of preliminary target designs was undertaken to ensure the overall feasibility of the concepts involved in the design and eventual construction of such a high power density target. Second, two proposed target designs, based on the first set of analyses, are investigated in more detail. Special care is taken to ensure that the neutron fluxes in the moderator are at the desired level no material compatibility problems exist,and the target is able to operate in a reliable and safe manner. Several target materials, coolant types, and target arrangements are investigated in the first section. The second section concentrates on a single target material and geometric arrangement. However, several structural material choices continue to be investigated with the aim of minimizing the effects of structural heating, and associated thermally induced stresses. In the final section the conclusions of this preliminary study are summarized
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