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Search Results: 1 - 10 of 297700 matches for " J. Healy "
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Restructuring Hospital Systems: Lessons Learned From Western Europe
McKee M,Healy J
Revue Médicale de l'Assurance Maladie , 2002,
Abstract: In many countries in Europe policy-makers are undertaking major restructuring of hospital systems, but with little evidence on which to base their decisions. This paper draws on a recent study of the role of the hospital in Europe undertaken by the European Observatory on Health Care Systems. Hospitals must take account not only of their role in treating patients but also their position as centres of teaching and research, and their responsibilities to the wider society. We characterise the pressures that hospitals face under three headings: population health needs; changes in health care; and wider societal and economic factors. Hospitals have changed as more people are admitted for active medical treatment but stay for shorter periods. The additional demands of growing numbers of ambulatory procedures make hospitals much busier than previously. Many countries have successfully reconfigured hospital systems, some more successful than others. Success is likely where a whole system approach is taken; granting autonomy to individual hospitals makes change less likely; while planning strategies have been more successful than market-based strategies. Change often requires new facilities. Increasingly rapid change in health care forces hospitals to adapt much more quickly than in the past, requiring a long-term programme of sustained and stable investment.
MD Simulations of Compression of Nanoscale Iron Pillars
Con J. Healy,Graeme J. Ackland
Physics , 2014, DOI: 10.1557/opl.2011.1512
Abstract: It is now possible to create perfect crystal nanowires of many metals. The deformation of such objects requires a good understanding of the processes involved in plasticity at the nanoscale. Isotropic compression of such nanometre scale micropillars is a good model system to understand the plasticity. Here we investigate these phenomena using Molecular Dynamics (MD) simulations of nanometre scale single crystal BCC iron pillars in compression. We find that pillars with large length to width ratio may buckle under high strain rates. The type of buckling behaviour depends sensitively on the boundary conditions used: periodic boundary conditions allow for rotation at top and bottom of the pillar, and result in an S shaped buckle, by contrast fixed boundaries enforce a C shape. Pillars with a length to width ratio closer to that used in experimental micropillar compression studies show deformation behaviour dominated by slip, in agreement with the experiments. For micropillars oriented along <100>, slip occurs on <110> planes and localized slip bands are formed. Pillars of this size experience higher stresses than bulk materials before yielding takes place. One might expect that this may be in part due to the lack of nucleation sites needed to induce slip. However, further simulations with possible dislocation sources: a shorter iron pillar containing a spherical grain boundary, and a similar pillar containing jagged edges did not show a decreased yield strength.
Letter to the Editor Abel transform inversion of radio occultation measurements made with a receiver inside the Earth’s atmosphere
S. B. Healy,J. Haase,O. Lesne
Annales Geophysicae (ANGEO) , 2003,
Abstract: Radio occultation measurements made with a receiver inside the Earth’s atmosphere can be inverted, assuming local spherical symmetry, with an Abel transform to provide an estimate of the atmospheric refractive index profile. The measurement geometry is closely related to problems encountered when inverting seismic time-travel data and solar occultation measurements, where the Abel solution is well known. The method requires measuring both rays that originate from above and below the local horizon of the receiver. The Abel transform operates on a profile of "partial bending angles" found by subtracting the positive elevation measurement from the negative elevation value with the same impact parameter. In principle, the refractive index profile can be derived from measurements with a single frequency GPS receiver because the ionospheric bending is removed when the partial bending angle is evaluated. Key words. Atmospheric composition and structure (pressure, density and temperature) – Radio science (remote sensing)
Gas/particle partitioning of carbonyls in the photooxidation of isoprene and 1,3,5-trimethylbenzene
R. M. Healy,J. C. Wenger,A. Metzger,J. Duplissy
Atmospheric Chemistry and Physics Discussions , 2008,
Abstract: A new denuder-filter sampling technique has been used to investigate the gas/particle partitioning behaviour of the carbonyl products from the photooxidation of isoprene and 1,3,5-trimethylbenzene. A series of experiments was performed in two atmospheric simulation chambers at atmospheric pressure and ambient temperature in the presence of NOx and at a relative humidity of approximately 50%. The denuder and filter were both coated with the derivatizing agent O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine (PFBHA) to enable the efficient collection of gas- and particle-phase carbonyls respectively. The tubes and filters were extracted and carbonyls identified as their oxime derivatives by GC-MS. The carbonyl products identified in the experiments accounted for around 5% and 10% of the mass of secondary organic aerosol formed from the photooxidation of isoprene and 1,3,5-trimethylbenzene respectively. Experimental gas/particle partitioning coefficients were determined for a wide range of carbonyl products formed from the photooxidation of isoprene and 1,3,5-trimethylbenzene and compared with the theoretical values based on standard absorptive partitioning theory. Photooxidation products with a single carbonyl moiety were not observed in the particle phase, but dicarbonyls, and in particular, glyoxal and methylglyoxal, exhibited gas/particle partitioning coefficients several orders of magnitude higher than expected theoretically. These findings support the importance of heterogeneous chemistry as a pathway for SOA formation and growth during the atmospheric degradation of anthropogenic and biogenic hydrocarbons.
A descriptive epidemiological study of mastitis in 12 Irish dairy herds
Damien J Barrett, Michael L Doherty, Anne M Healy
Irish Veterinary Journal , 2005, DOI: 10.1186/2046-0481-58-1-31
Abstract: Herds with a ratio of less than 110 cubicles per 100 cows were more likely to experience environmental mastitis. Herds with inadequate calving facilities, where cows spent prolonged periods on straw bedding, were likely to acquire environmental mastitis. In the majority of the herds, the selection of dry cow therapy lacked adequate planning. The majority of farmers took no action to reduce pain experienced by cows suffering mastitis. Deficiencies in parlour hygiene were evident in all herds experiencing elevation in SCC.Bovine mastitis may be classified as contagious or environmental. The main contagious pathogens are Staphylococcus aureus and Streptococcus species. Although Streptococcus uberis is environmental in origin, it can be spread from cow to cow in a manner similar to that for contagious mastitis organisms. The mammary gland and udder skin act as reservoirs of infection in contagious mastitis. Infection is acquired during udder preparation or during the milking process. The presence of carrier cows in the herd, inappropriate milking practices and milking machine malfunction are all known to contribute to the development of mastitis. The cow's environment is the reservoir of infection for environmental mastitis. The prevalence of environmental mastitis relates to the level of teat-end exposure to the causative agents, namely Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Pseudomonas aeruginosa, and Streptococcus uberis. Coliform infections are generally of short duration. Streptococcus uberis infections often become chronic and can be very difficult to cure [13]. These bacteria survive best in wet, warm, humid and dirty conditions [15]. Successful management of environmental mastitis requires minimising teat-end exposure to faecal material, reducing the bacterial load on cow-lying areas and reducing bacterial survival [14]. There must be sufficient numbers of comfortable cubicles of an adequate size to maximi
Quantitative comparison of myocardial fiber structure between mice, rabbit, and sheep using diffusion tensor cardiovascular magnetic resonance
Lindsey J Healy, Yi Jiang, Edward W Hsu
Journal of Cardiovascular Magnetic Resonance , 2011, DOI: 10.1186/1532-429x-13-74
Abstract: Fixed mouse (n = 10), rabbit (n = 6), and sheep (n = 5) hearts underwent diffusion tensor imaging (DTI). The myocardial structures in terms of the left ventricular fiber orientation helix angle index were quantitatively compared between the mouse rabbit and sheep hearts.The results show that significant fiber structural differences exist between any two of the three species. Specifically, the subepicardial fiber orientation, and the transmural range and linearity of fiber helix angles are significantly different between the mouse and either rabbit or sheep. Additionally, a significant difference was found between the transmural helix angle range between the rabbit and sheep. Across different circumferential regions of the heart, the fiber orientation was not found to be significantly different.The current study indicates that myocardial structural differences exist between different size hearts. An immediate implication of the present findings for myocardial structural or functional modeling studies is that caution must be exercised when extrapolating myocardial structures from one species to another.Computational studies are increasingly used to help interpret empirical measurements or to investigate functions of the body beyond experimental limitations. Because structures of the myocardium such as the fiber orientation play a deterministic role in its material properties and functional behaviours, accurate simulations of cardiac functions require precise anatomical models of the myocardium. Anatomy-based models of the myocardium have been used in computational studies of both electrophysiology [1,2] and mechanics [3-5] of the heart. In electrophysiological studies, utilizing anisotropic fiber orientation information has led to improved predictions of the electrical activity in the heart [2,6]. Similarly, incorporation of fiber structure into mechanical models has helped better explain the structure-function relationships [7,8].Despite the significance of the infor
Effect of integrated traditional Chinese medicine and western medicine on the treatment of severe acute respiratory syndrome: A meta-analysis
Chen,Yan; Guo,Jeff J.; Healy,Daniel P.; Zhan,Siyan;
Pharmacy Practice (Internet) , 2007, DOI: 10.4321/S1886-36552007000100001
Abstract: background: data regarding the treatment efficacy of integrative treatment of traditional chinese medicine (tcm) and western medicine (wm) in treating patients with (sars) are conflicting. the effects of integrative tcm/wm treatment have not been fully quantified. objectives: to systematically asses the treatment effects of integrated tcm with wm versus wm alone in patients with sars, incorporating data from recently published studies. methods: a meta-analysis was conducted, using published randomized and nonrandomized controlled clinical studies that compared the treatment effects of integrative tcm/wm with wm alone from 2002 to 2006.the outcome measurements included mortality rate, cure rate, resolution of pulmonary infiltrate, use of corticosteroid, and time to defervescence. the effect sizes were presented as risk ratio (rr), rate difference (rd), and weighted mean difference (wmd).the pooled effect sizes were calculated by both fixed-effects and random-effects models. results: a total of 1,678 patients with a diagnosis of sars were identified, including 866 patients from 16 randomized controlled studies and 812 patients from 8 nonrandomized controlled studies. there were no differences detected in mortality rate or cure rate between treatments. compared with patients receiving wm treatment alone, patients receiving integrative treatment were more likely to have complete or partial resolution of pulmonary infiltrate (rd=0.18, 95%ci; 0.07 to 0.30), lower average daily dosage (mg) of corticosteroid (wmd=-60.27, 95% ci; -70.58 to -49.96), higher cd4+ counts (cells/ul) (wmd=167.96, 95% ci; 109.68 to 226.24), and shorter time to defervescence (days) (wmd= -1.06, 95%ci;-1.60 to -0.53). conclusions: the experience of integrative tcm/wm in the treatment of sars is encouraging. the use of tcm as an adjunctive therapy in the treatment of sars should be further investigated.
Quantitative determination of carbonaceous particle mixing state in Paris using single particle mass spectrometer and aerosol mass spectrometer measurements
R. M. Healy,J. Sciare,L. Poulain,M. Crippa
Atmospheric Chemistry and Physics Discussions , 2013, DOI: 10.5194/acpd-13-10345-2013
Abstract: Single particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been estimated using an aerosol time-of-flight mass spectrometer (ATOFMS) as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC), organic aerosol (OA), ammonium, nitrate, sulphate and potassium were compared with concurrent measurements from an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), a thermal/optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC). ATOFMS-derived mass concentrations reproduced the variability of these species well (R2 = 0.67–0.78), and ten discrete mixing states for carbonaceous particles were identified and quantified. Potassium content was used to identify particles associated with biomass combustion. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorization, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA) detected in Paris is associated with two EC-rich mixing states which differ in their relative sulphate content, while fresh biomass burning OA (BBOA) is associated with two mixing states which differ significantly in their OA/EC ratios. Aged biomass burning OA (OOA2-BBOA) was found to be significantly internally mixed with nitrate, while secondary, oxidized OA (OOA) was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the heterogeneity of primary and secondary organic aerosol mixing states in Paris. Examination of the temporal behaviour and chemical composition of the ATOFMS classes also enabled estimation of the relative contribution of transported emissions of each chemical species and total particle mass in the size range investigated. Only 22% of the total ATOFMS-derived particle mass was apportioned to fresh, local emissions, with 78% apportioned to regional/continental scale emissions.
Perturbative extraction of gravitational waveforms generated with Numerical Relativity
H. Nakano,J. Healy,C. O. Lousto,Y. Zlochower
Physics , 2015, DOI: 10.1103/PhysRevD.91.104022
Abstract: We derive an analytical expression for extracting the gravitational waveforms at null infinity using the Weyl scalar $\psi_4$ measured at a finite radius. Our expression is based on a series solution in orders of 1/r to the equations for gravitational perturbations about a spinning black hole. We compute this expression to order $1/r^2$ and include the spin parameter $a$ of the Kerr background. We test the accuracy of this extraction procedure by measuring the waveform for a merging black-hole binary at ten different extraction radii (in the range r/M=75-190) and for three different resolutions in the convergence regime. We find that the extraction formula provides a set of values for the radiated energy and momenta that at finite extraction radii converges towards the expected values with increasing resolution, which is not the case for the `raw' waveform at finite radius. We also examine the phase and amplitude errors in the waveform as a function of observer location and again observe the benefits of using our extraction formula. The leading corrections to the phase are ${\cal O}(1/r)$ and to the amplitude are ${\cal O}(1/r^2)$. This method provides a simple and practical way of estimating the waveform at infinity, and may be especially useful for scenarios such as well separated binaries, where the radiation zone is far from the sources, that would otherwise require extended simulation grids in order to extrapolate the `raw' waveform to infinity. Thus this method saves important computational resources and provides an estimate of errors.
Precession during merger 1: Strong polarization changes are observationally accessible features of strong-field gravity during binary black hole merger
R. O'Shaughnessy,L. London,J. Healy,D. Shoemaker
Physics , 2012, DOI: 10.1103/PhysRevD.87.044038
Abstract: The short gravitational wave signal from the merger of compact binaries encodes a surprising amount of information about the strong-field dynamics of merger into frequencies accessible to ground-based interferometers. In this paper we describe a previously-unknown "precession" of the peak emission direction with time, both before and after the merger, about the total angular momentum direction. We demonstrate the gravitational wave polarization encodes the orientation of this direction to the line of sight. We argue the effects of polarization can be estimated nonparametrically, directly from the gravitational wave signal as seen along one line of sight, as a slowly-varying feature on top of a rapidly-varying carrier. After merger, our results can be interpreted as a coherent excitation of quasinormal modes of different angular orders, a superposition which naturally "precesses" and modulates the line-of-sight amplitude. Recent analytic calculations have arrived at a similar geometric interpretation. We suspect the line-of-sight polarization content will be a convenient observable with which to define new high-precision tests of general relativity using gravitational waves. Additionally, as the nonlinear merger process seeds the initial coherent perturbation, we speculate the amplitude of this effect provides a new probe of the strong-field dynamics during merger. To demonstrate the ubiquity of the effects we describe, we summarize the post-merger evolution of 104 generic precessing binary mergers. Finally, we provide estimates for the detectable impacts of precession on the waveforms from high-mass sources. These expressions may identify new precessing binary parameters whose waveforms are dissimilar from the existing sample.
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