428 research outputs found
The occurrence of uranium at Kilembe Mine, Uganda
Kilembe mine is situated on the lower eastern slopes of Mt. Ruwensori, which forms the borderland between Uganda and the Belgian Congo. The property is in a fairly advanced stage of development, the enterprise being capitalized jointly by Frobisher Ltd. and Rio Tinto Ltd.
The ore-bodies occupy thin-banded, usually crushed, horizons in a series of folded fine-grained metamorphic rocks (granulites and amphibolites), probably of Pre-cambrian age. Mineralization is believed to be related to a prolific series of alaskite dykes which intrude the granulites, usually along their banding. Extensive faulting, as well as the emplacement of basic dykes, has taken place following mineralisation.
The ore-bodies have been developed by means of a number of adits at various levels, running into the hillsides on both flanks of a valley. So far over 11,000 feet of underground development has taken place, as well as over 40,000 feet of diamond drilling.
The ores contain about 2% copper and 0.18% cobalt, as well as a little gold, silver and nickel. The occurrences of uranium so far found have been confined to one or two very local patches, usually in the form of torbernite (copper uranium phosphate), lining cracks either as small individual crystals or, in association with other copper minerals, as narrow fissure fillings. Radiometric examination of these uraniferous concentrations shows that radioactivity diminishes very markedly over a small distance, both
horizontally and vertically. Elsewhere, the background readings underground are generally extremely low and tests of mine adit drainage water and diamond drill cores have so far yielded no encouraging results whatever.
On present evidence this uranium occurrence is regarded as of academic interest only. It is recommended that, as development continues, further routine radiometric tests should be made from time to time, covering both new extensions of the workings and new sections of drill core
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An Investigation of the Effects of Quantum Dot Nanoparticles on Photopolymer Resin for Use in PolyJet Direct 3D Printing
The addition of quantum dot (QD) nanoparticles to additive manufacturing (AM) media
provides the opportunity to create artifacts with complex geometry that also have unique optical
characteristics. However, the addition of nanoparticles can significantly alter the rheology of a
material and make it difficult to process in an AM context. In this study, quantum dots were
added to a photopolymer resin in varying mass ratios to photopolymer, and their effects on the
viscosity, surface tension, and jetting ability of the suspension were investigated. Results show
that printability was not significantly affected by the presence of quantum dots in mass
concentrations less than or equal to 0.5%. The nanosuspensions were deposited via inkjet to
demonstrate the feasibility of creating optically-unique artifacts.Mechanical Engineerin
Baling straw for ethanol production: the long-term implications on soil quality and productivity
Non-Peer Reviewe
Translation to practice: a randomised controlled study of an evidenced based booklet targeted at breast care nurses in the United Kingdom
BACKGROUND: In the United Kingdom (UK), it was documented that a problem of knowledge transfer existed within the speciality of breast-cancer care, thus depriving patients of receiving optimal care. Despite increasingly robust research evidence indicating recommendation of whole body exercise for people affected by breast cancer, commensurate changes to practice were not noted amongst breast-care nurses (BCNs).
AIM: To evaluate the effect of a targeted booklet, Exercise and Breast Cancer: A Booklet for Breast-Care Nurses, on changes in knowledge, reported practice, and attitudes of BCNs in the UK.
METHOD: A prospective, experimental approach was used for designing a pre- and post-test randomised controlled study. Comparisons of knowledge, reported practice, and attitudes based on responses to a questionnaire were made at two time-points in two groups of BCNs (control and experimental). The unit of randomisation and analysis was hospital clusters of BCNs. The sample comprised 92 nurses from 62 hospitals. Analysis consisted of descriptive statistics and clustered regression techniques: clustered logistic regression for knowledge items, clustered linear regression for knowledge scores, ologit for attitude and reported practice items, and clustered multiple regression for paired and multiple variable analysis.
RESULTS: A statistically significant increase in knowledge and changes in reported practice and attitudes were found. Robust variables affecting knowledge acquisition were: promotion of health, promotion of exercise, and understanding how exercise can reduce cancer-related fatigue.
DISCUSSION: The study has shown that evidence-based printed material, such as an information booklet, can be used as an effective research dissemination method when developed for needs, values, and context of a target audience.
CONCLUSIONS: This practical approach to research dissemination could be replicated and applied to other groups of nurses.</p
Primordial nucleosynthesis with a varying fine structure constant: An improved estimate
We compute primordial light-element abundances for cases with fine structure
constant alpha different from the present value, including many sources of
alpha dependence neglected in previous calculations. Specifically, we consider
contributions arising from Coulomb barrier penetration, photon coupling to
nuclear currents, and the electromagnetic components of nuclear masses. We find
the primordial abundances to depend more weakly on alpha than previously
estimated, by up to a factor of 2 in the case of ^7Li. We discuss the
constraints on variations in alpha from the individual abundance measurements
and the uncertainties affecting these constraints. While the present best
measurements of primordial D/H, ^4He/H, and ^7Li/H may be reconciled pairwise
by adjusting alpha and the universal baryon density, no value of alpha allows
all three to be accommodated simultaneously without consideration of systematic
error. The combination of measured abundances with observations of acoustic
peaks in the cosmic microwave background favors no change in alpha within the
uncertainties.Comment: Phys. Rev. D accepted version; minor changes in response to refere
Kaon-Nucleon Scattering Amplitudes and Z-Enhancements from Quark Born Diagrams
We derive closed form kaon-nucleon scattering amplitudes using the ``quark
Born diagram" formalism, which describes the scattering as a single interaction
(here the OGE spin-spin term) followed by quark line rearrangement. The low
energy I=0 and I=1 S-wave KN phase shifts are in reasonably good agreement with
experiment given conventional quark model parameters. For Gev
however the I=1 elastic phase shift is larger than predicted by Gaussian
wavefunctions, and we suggest possible reasons for this discrepancy. Equivalent
low energy KN potentials for S-wave scattering are also derived. Finally we
consider OGE forces in the related channels K, KN and K,
and determine which have attractive interactions and might therefore exhibit
strong threshold enhancements or ``Z-molecule" meson-baryon bound states.
We find that the minimum-spin, minimum-isospin channels and two additional
K channels are most conducive to the formation of bound states.
Related interesting topics for future experimental and theoretical studies of
KN interactions are also discussed.Comment: 34 pages, figures available from the authors, revte
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Risk Owners & Risk Managers: Dealing with the complexity of feeding children with neurodevelopmental disability
This paper illustrates negotiations around risk between lay people and clinicians in relation to gastrostomy interventions for disabled children. These negotiations centre on differing interpretations of what constitutes risk in relation to the safety of oral feeding and a child's need for a feeding tube between parents, carers and clinical specialties. Drawing on Heyman's distinction between risk managers and risk owners, we show that not only do clinicians act as risk managers and parents and carers as risk owners, but that these distinctions often become blurred either because of the shifting dynamics of relations of care or because of the specificity of clinical practice. Parents become risk managers in relation to carers' roles, while clinicians become risk owners in relation to particular procedures which define their practice. This has implications for lay and expert interactions as well as professional accountability for those caring for children with complex medical conditions. Although not an empirical article, we draw on empirical work in the UK. We analyse both parental and professional constructions of risk based on observations of co-ordinating a clinical trial designed to evaluate the effectiveness of gastrostomy surgery. We also examine the diverse value systems used by different groups of professionals and lay carers which inform judgements about risk and feeding. We conclude by arguing that issues of risk in contemporary health care are not just examples of ‘manufactured uncertainty’ or of ‘negotiated power’ but constitute a dialectical relationship which breaks down the essentialist dualism of lay and professional constructions of risk
Longitudinal measures of RNA expression and disease activity in FSHD muscle biopsies
Advances in understanding the pathophysiology of facioscapulohumeral dystrophy (FSHD) have led to the discovery of candidate therapeutics, and it is important to identify markers of disease activity to inform clinical trial design. For drugs that inhibit DUX4 expression, measuring DUX4 or DUX4-target gene expression might be an interim measure of drug activity; however, only a subset of FHSD muscle biopsies shows evidence of DUX4 expression. Our prior study showed that MRI T2-STIR-positive muscles had a higher probability of showing DUX4 expression than muscles with normal MRI characteristics. In the current study, we performed a 1-year follow-up assessment of the same muscle with repeat MRI and muscle biopsy. There was little change in MRI characteristics over the 1-year period and, similar to the initial evaluation, MRI T2-STIR-postive muscles had a higher expression of DUX4-regulated genes, as well as genes associated with inflammation, extracellular matrix and cell cycle. Compared to the initial evaluation, overall the level of expression in these gene categories remained stable over the 1-year period; however, there was some variability for each individual muscle biopsied. The pooled data from both the initial and 1-year follow-up evaluations identified several FSHD subgroups based on gene expression, as well as a set of genes-composed of DUX4-target genes, inflammatory and immune genes and cell cycle control genes-that distinguished all of the FSHD samples from the controls. These candidate markers of disease activity need to be replicated in independent datasets and, if validated, may provide useful measures of disease progression and response to therapy.Functional Genomics of Muscle, Nerve and Brain Disorder
Equations for the estimation of strong ground motions from shallow crustal earthquakes using data from Europe and the Middle East : vertical peak ground acceleration and spectral acceleration
This article presents equations for the estimation of vertical strong ground motions caused by shallow crustal earthquakes with magnitudes M w 5 and distance to the surface projection of the fault less than 100km. These equations were derived by weighted regression analysis, used to remove observed magnitude-dependent variance, on a set of 595 strong-motion records recorded in Europe and the Middle East. Coefficients are included to model the effect of local site effects and faulting mechanism on the observed ground motions. The equations include coefficients to model the observed magnitude-dependent decay rate. The main findings of this study are that: short-period ground motions from small and moderate magnitude earthquakes decay faster than the commonly assumed 1/r, the average effect of differing faulting mechanisms is similar to that observed for horizontal motions and is not large and corresponds to factors between 0.7 (normal and odd) and 1.4 (thrust) with respect to strike-slip motions and that the average long-period amplification caused by soft soil deposits is about 2.1 over those on rock sites
Effect of atrial fibrillation on endovascular thrombectomy for acute ischemic stroke. A meta-analysis of individual patient data from six randomised trials: Results from the HERMES collaboration
Background: Atrial fibrillation is an important risk factor for ischemic stroke, and is associated with an increased risk of poor outcome after ischemic stroke. Endovascular thrombectomy is safe and effective in acute ischemic stroke patients with large vessel occlusion of the anterior circulation. This meta-analysis aims to investigate whether there is an interaction between atrial fibrillation and treatment effect of endovascular thrombectomy, and secondarily whether atrial fibrillation is associated with worse outcome in patients with ischemic stroke due to large vessel occlusion. Methods: Individual patient data were from six of the recent randomised clinical trials (MR CLEAN, EXTEND-IA, REVASCAT, SWIFT PRIME, ESCAPE, PISTE) in which endovascular thrombectomy plus standard care was compared to standard care alone. Primary outcome measure was the shift on the modified Rankin scale (mRS) at 90 days. Secondary outcomes were functional independence (mRS 0–2) at 90 days, National Institutes of Health Stroke Scale score at 24 h, symptomatic intracranial hemorrhage and mortality at 90 days. The primary effect parameter was the adjusted common odds ratio, estimated with ordinal logistic regression (shift analysis); treatment effect modification of atrial fibrillation was assessed with a multiplicative interaction term. Results: Among 1351 patients, 447 p
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