221 research outputs found
Fourier spectra of measures associated with algorithmically random Brownian motion
In this paper we study the behaviour at infinity of the Fourier transform of
Radon measures supported by the images of fractal sets under an algorithmically
random Brownian motion. We show that, under some computability conditions on
these sets, the Fourier transform of the associated measures have, relative to
the Hausdorff dimensions of these sets, optimal asymptotic decay at infinity.
The argument relies heavily on a direct characterisation, due to Asarin and
Pokrovskii, of algorithmically random Brownian motion in terms of the prefix
free Kolmogorov complexity of finite binary sequences. The study also
necessitates a closer look at the potential theory over fractals from a
computable point of view.Comment: 24 page
The Scotch metaphysics
Hume and the Rankenien Society,
Reid,
Stewart,
Brown, Hamilton and Ferrie
Kolmogorov complexity and recursive events
Please read the abstract in the section 00front of this documentThesis (PhD (Mathematics))--University of Pretoria, 2000.Mathematics and Applied Mathematicsunrestricte
Environmental Water Quality - a guide to sampling and measurement
The guide covers the problems associated with sampling water in the field and suggestions to overcome them. The main types of water pollution that potentially occur in the south west of Western Australia are discussed and for each contaminant, the origins and environmental effects are briefly described and where available, water quality guidelines are provided for major water uses. This is followed by specific requirements of the collection, storage and analysis of samples. The guide also includes further reading and details on suppliers, analytical costs and web resources
Distribution, Habitat Use, and Morphotypes of Feral Hogs (\u3ci\u3eSus scrofa\u3c/i\u3e) in Illinois
Feral hogs (Sus scrofa) recently have been introduced to Illinois. They are important to resource managers because of their potentially negative ecological and economic impacts. We assessed the distribution, habitat use, and body morphology of feral hogs in Illinois. We confirmed the occurrence of feral hogs in Fulton, Hardin, Johnson, Lawrence, Massac, Pope, Randolph, and Union counties. Forest and croplands probably are the most important habitats for feral hogs in Illinois. We found free-ranging hogs in Illinois included four previously described morphotypes with distinguishable physical/cranial characteristics: domestic hogs, feral hogs, hybrids, and Eurasian wild hogs. However, 32.6% of individuals were outside of these previously described morphotypes. External morphology and pelage usually were consistent with cranial analysis in determining morphotypes. Whole and dressed body weight regression indicated that dressed weight was about 85% of whole weight. We suggest that the goal of resource managers in Illinois should be to contain or eradicate existing feral hog populations. This should be addressed while populations are small and relatively isolated. If current practices continue, feral hogs have the potential to eventually increase in density and distribution throughout much of Illinois
Kolmogorov Complexity, Circuits, and the Strength of Formal Theories of Arithmetic
Can complexity classes be characterized in terms of efficient reducibility to the (undecidable) set of Kolmogorov-random strings? Although this might seem improbable, a series of papers has recently provided evidence that this may be the case. In particular, it is known that there is a class of problems C defined in terms of polynomial-time truth-table reducibility to RK (the set of Kolmogorov-random strings) that lies between BPP and PSPACE [4, 3]. In this paper, we investigate improving this upper bound from PSPACE to PSPACE â© P/poly. More precisely, we present a collection of true statements in the language of arithmetic, (each provable in ZF) and show that if these statements can be proved in certain extensions of Peano arithmetic, then BPP âCâPSPACE â© P/poly. We conjecture that C is equal to P, and discuss the possibility this might be an avenue for trying to prove the equality of BPP and P
Measuring the quality and quantity of professional intrapartum support: Testing a computerised systematic observation tool in the clinical setting
Background: Continuous support in labour has a significant impact on a range of clinical outcomes, though whether the quality and quantity of support behaviours affects the strength of this impact has not yet been established. To identify the quality and quantity of support, a reliable means of measurement is needed. To this end, a new computerised systematic observation tool, the ‘SMILI' (Supportive Midwifery in Labour Instrument) was developed. The aim of the study was to test the validity and usability of the ‘Supportive Midwifery in Labour Instrument' (SMILI) and to test the feasibility and acceptability of the systematic observation approach in the clinical intrapartum setting. Methods: Systematic observation was combined with a postnatal questionnaire and the collection of data about clinical processes and outcomes for each observed labour. The setting for the study was four National Health Service maternity units in Scotland, UK. Participants in this study were forty five midwives and forty four women. The SMILI was used by trained midwife observers to record labour care provided by midwives. Observations were undertaken for an average of two hours and seventeen minutes during the active first stage of labour and, in 18 cases, the observation included the second stage of labour. Content validity of the instrument was tested by the observers, noting the extent to which the SMILI facilitated the recording of all key aspects of labour care and interactions. Construct validity was tested through exploration of correlations between the data recorded and women's feelings about the support they received. Feasibility and usability data were recorded following each observation by the observer. Internal reliability and construct validity were tested through statistical analysis of the data. Results: One hundred and four hours of labour care were observed and recorded using the SMILI during forty nine labour episodes. Conclusion: The SMILI was found to be a valid and reliable instrument in the intrapartum setting in which it was tested. The study identified that the SMILI could be used to test correlations between the quantity and quality of support and outcomes. The systematic observational approach was found to be an acceptable and feasible method of enquiry
Study protocol: MyoFit46-the cardiac sub-study of the MRC National Survey of Health and Development
BACKGROUND: The life course accumulation of overt and subclinical myocardial dysfunction contributes to older age mortality, frailty, disability and loss of independence. The Medical Research Council National Survey of Health and Development (NSHD) is the world's longest running continued surveillance birth cohort providing a unique opportunity to understand life course determinants of myocardial dysfunction as part of MyoFit46-the cardiac sub-study of the NSHD. METHODS: We aim to recruit 550 NSHD participants of approximately 75 years+ to undertake high-density surface electrocardiographic imaging (ECGI) and stress perfusion cardiovascular magnetic resonance (CMR). Through comprehensive myocardial tissue characterization and 4-dimensional flow we hope to better understand the burden of clinical and subclinical cardiovascular disease. Supercomputers will be used to combine the multi-scale ECGI and CMR datasets per participant. Rarely available, prospectively collected whole-of-life data on exposures, traditional risk factors and multimorbidity will be studied to identify risk trajectories, critical change periods, mediators and cumulative impacts on the myocardium. DISCUSSION: By combining well curated, prospectively acquired longitudinal data of the NSHD with novel CMR-ECGI data and sharing these results and associated pipelines with the CMR community, MyoFit46 seeks to transform our understanding of how early, mid and later-life risk factor trajectories interact to determine the state of cardiovascular health in older age. TRIAL REGISTRATION: Prospectively registered on ClinicalTrials.gov with trial ID: 19/LO/1774 Multimorbidity Life-Course Approach to Myocardial Health- A Cardiac Sub-Study of the MCRC National Survey of Health and Development (NSHD)
Pleiotropic effects of statins in distal human pulmonary artery smooth muscle cells
<p>Abstract</p> <p>Background</p> <p>Recent clinical data suggest statins have transient but significant effects in patients with pulmonary arterial hypertension. In this study we explored the molecular effects of statins on distal human pulmonary artery smooth muscle cells (PASMCs) and their relevance to proliferation and apoptosis in pulmonary arterial hypertension.</p> <p>Methods</p> <p>Primary distal human PASMCs from patients and controls were treated with lipophilic (simvastatin, atorvastatin, mevastatin and fluvastatin), lipophobic (pravastatin) and nitric-oxide releasing statins and studied in terms of their DNA synthesis, proliferation, apoptosis, matrix metalloproteinase-9 and endothelin-1 release.</p> <p>Results</p> <p>Treatment of human PASMCs with selected statins inhibited DNA synthesis, proliferation and matrix metalloproteinase-9 production in a concentration-dependent manner. Statins differed in their effectiveness, the rank order of anti-mitogenic potency being simvastatin > atorvastatin > > pravastatin. Nevertheless, a novel nitric oxide-releasing derivative of pravastatin (NCX 6550) was effective. Lipophilic statins, such as simvastatin, also enhanced the anti-proliferative effects of iloprost and sildenafil, promoted apoptosis and inhibited the release of the mitogen and survival factor endothelin-1. These effects were reversed by mevalonate and the isoprenoid intermediate geranylgeranylpyrophosphate and were mimicked by inhibitors of the Rho and Rho-kinase.</p> <p>Conclusions</p> <p>Lipophilic statins exert direct effects on distal human PASMCs and are likely to involve inhibition of Rho GTPase signalling. These findings compliment some of the recently documented effects in patients with pulmonary arterial hypertension.</p
Frequency-Domain vs Continuous-Wave Near-Infrared Spectroscopy devices:A comparison of clinically viable monitors in controlled hypoxia
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