2,071 research outputs found
An ultrasonic frequency sweep interferometer for liquids at high temperature: 1. Acoustic model
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95075/1/jgrb14010.pd
Engineering polymer informatics: Towards the computer-aided design of polymers
The computer-aided design of polymers is one of the holy grails of modern chemical
informatics and of significant interest for a number of communities in polymer
science. The paper outlines a vision for the in silico design of polymers and presents
an information model for polymers based on modern semantic web technologies, thus
laying the foundations for achieving the vision
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Designing theoretically-informed implementation interventions
Clinical and health services research is continually producing new findings that may contribute to effective and efficient patient care. However, the transfer of research findings into practice is unpredictable and can be a slow and haphazard process. Ideally, the choice of implementation strategies would be based upon evidence from randomised controlled trials or systematic reviews of a given implementation strategy. Unfortunately, reviews of implementation strategies consistently report effectiveness some, but not all of the time; possible causes of this variation are seldom reported or measured by the investigators in the original studies. Thus, any attempts to extrapolate from study settings to the real world are hampered by a lack of understanding of the effects of key elements of individuals, interventions, and the settings in which they were trialled. The explicit use of theory offers a way of addressing these issues and has a number of advantages, such as providing: a generalisable framework within which to represent the dimensions that implementation studies address, a process by which to inform the development and delivery of interventions, a guide when evaluating, and a way to allow for an exploration of potential causal mechanisms. However, the use of theory in designing implementation interventions is methodologically challenging for a number of reasons, including choosing between theories and faithfully translating theoretical constructs into interventions. The explicit use of theory offers potential advantages in terms of facilitating a better understanding of the generalisability and replicability of implementation interventions. However, this is a relatively unexplored methodological area
The information needs of people living with ankylosing spondylitis: a questionnaire survey
<p>BACKGROUND:Today, health care is patient-centred with patients more involved in medical decision making and taking an active role in managing their disease. It is important that patients are appropriately informed about their condition and that their health care needs are met. We examine the information utilisation, sources and needs of people with ankylosing spondylitis (AS).</p>
<p>METHODS: Participants in an existing AS cohort study were asked to complete a postal or online questionnaire containing closed and open-ended questions, regarding their information access and needs. Participants were stratified by age and descriptive statistics were performed using STATA 11, while thematic analysis was performed on open-ended question narratives. Qualitative data was handled in Microsoft Access and explored for emerging themes and patterns of experiences.</p>
<p>RESULTS: Despite 73% of respondents having internet access, only 49% used the internet to access information regarding AS. Even then, this was only infrequently. Only 50% of respondents reported accessing written information about AS, which was obtained mainly in specialist clinics. Women were more likely than men to access information (63% (women) 46% (men)) regardless of the source, while younger patients were more likely to use online sources. The main source of non-written information was the rheumatologist. Overall, the respondents felt there was sufficient information available, but there was a perception that the tone was often too negative. The majority (95%) of people would like to receive a regular newsletter about AS, containing positive practical and local information. Suggestions were also made for more information about AS to be made available to non-specialist medical professionals and the general public.</p>
<p>CONCLUSIONS: There appears to be sufficient information available for people with AS in the UK and this is mostly accessed by younger AS patients. Many patients, particularly men, choose not to access AS information and concerns were raised about its negative tone. Patients still rely on written and verbal information from their specialists. Future initiatives should focus on the delivery of more positive information, targeting younger participants in particular and increasing the awareness in the general population and wider non-specialist medical community.</p>
Density Dependent Hadron Field Theory
A fully covariant approach to a density dependent hadron field theory is
presented. The relation between in--medium NN interactions and
field--theoretical meson--nucleon vertices is discussed. The medium dependence
of nuclear interactions is described by a functional dependence of the
meson--nucleon vertices on the baryon field operators. As a consequence, the
Euler--Lagrange equations lead to baryon rearrangement self--energies which are
not obtained when only a parametric dependence of the vertices on the density
is assumed. It is shown that the approach is energy--momentum conserving and
thermodynamically consistent. Solutions of the field equations are studied in
the mean--field approximation. Descriptions of the medium dependence in terms
of the baryon scalar and vector density are investigated. Applications to
infinite nuclear matter and finite nuclei are discussed. Density dependent
coupling constants obtained from Dirac--Brueckner calculations with the Bonn
NN-potentials are used. Results from Hartree calculations for energy spectra,
binding energies and charge density distributions of , and
are presented. Comparisons to data strongly support the importance
of rearrangement in a relativistic density dependent field theory. Most
striking is the simultanuous improvement of charge radii, charge densities and
binding energies. The results indicate the appearance of a new "Coester line"
in the nuclear matter equation of state.Comment: 48 LateX pages, 12 Figures, figures and full paper are available as
postscript files by anonymous ftp at ftp://theorie.physik.uni-giessen.de/dd
Impact of air pollution on educational attainment for respiratory health treated students: A cross sectional data linkage study
Introduction: There is some evidence that exam results are worse when students are acutely exposed to air pollution. Studies investigating the association between air pollution and academic attainment have been constrained by small sample sizes. Methods: Cross sectional educational attainment data (2009–2015) from students aged 15–16 years in Cardiff, Wales were linked to primary health care data, modelled air pollution and measured pollen data, and analysed using multilevel linear regression models. Annual cohort, school and individual level confounders were adjusted for in single and multi-pollutant/pollen models. We stratified by treatment of asthma and/or Seasonal Allergic Rhinitis (SAR). Results: A unit (10μg/m3) increase of short-term exposure to NO2 was associated with 0.044 (95% CI: −0.079, −0.008) reduction of standardised Capped Point Score (CPS) after adjusting for individual and household risk factors for 18,241 students. This association remained statistically significant after controlling for other pollutants and pollen. There was no association of PM2.5, O3, or Pollen with standardised CPS remaining after adjustment. We found no evidence that treatment for asthma or SAR modified the observed NO2 effect on educational attainment. Conclusion: Our study showed that short-term exposure to traffic-related air pollution, specifically NO2, was associated with detrimental educational attainment for students aged 15–16. Longitudinal investigations in different settings are required to confirm this possible impact and further work may uncover the long-term economic implications, and degree to which impacts are cumulative and permanent
Cognitive development Respiratory Tract Illness and Effects of eXposure (CORTEX) project: Data processing challenges in combining high spatial resolution pollution level data with individual level health and education data
Background and Objectives: There is a lack of evidence of the adverse effects of air pollution and pollen on cognition for people with air quality-related health conditions. The CORTEX project combined routinely collected health and education data, high spatial resolution air pollution modelling, and daily pollen measurements for 18,241 pupils living in Cardiff, UK, between 2009 and 2015, to investigate the acute effects of air quality and respiratory conditions on education attainment. Datasets: Air pollutants PM2.5, PM10, NO2, and ozone levels were modelled for 157,361 home and school locations, anonymised into the Secure Anonymised Information Linkage (SAIL) Databank, and summarised into minimum, average and maximum readings for 4 daily time periods reflecting pupil home/school exposure. Adding a unique Residential Anonymised Linking Field (RALF) allowed linkage of pollution estimates to individual level data. Annual pollution datasets contained 369 columns and 472,083-rows, with one column per location, pollutant, daily time-period and day of year. Dataset transformation produced a 5 column, 3,446,205,900-row matrix per year. Methods and Conclusions: An algorithm using Structured Query Language (SQL) to manage data held within a relational database management system, was designed to reduce dimensionality from 24 billion to 18,241 rows of data. The algorithm calculated average means for each pollutant (PM2.5, PM10, NO2, and ozone levels) over the revision and examination periods, and summarised data into one row per pupil. The algorithm adjusted for weekends, school, and bank holidays, it calculated daily pollutant exposure for each pupil, and successfully linked 95% of pupil pollution exposures to their health and education data
Relationship between parental locus of control and caries experience in preschool children – cross-sectional survey
Background:
Due to high prevalence and serious impacts, childhood caries represents a public health issue. Behavioural risk factors such as locus of health control have been implicated in the development of the disease; however their association with childhood caries has not been thoroughly studied. The aim of this cross-sectional survey was to assess the relationship between parental locus of health control and caries experience and untreated caries of their preschool children in a representative sample in Czech Republic, adjusting for relevant sociodemographic characteristics.
Methods:
A representative sample of 285 preschool children and their parents was recruited. Study data included children's dental status recorded in nurseries and parental questionnaires with 13 attitudinal items regarding locus of control (LoC) in caries prevention. The association between parental locus of control and children's caries experience and level of untreated caries was analysed using logistic regression, adjusting for the effect of key sociodemographic variables.
Results:
There was a statistically highly significant linear trend between increased parental LoC and higher probability of the children to be free from untreated caries, independent from the effect of sociodemographic variables of children and parents. A similar highly statistically significant trend, although not entirely linear, and independent from sociodemographic variables was observed with respect to the chance of the children to be free from caries experience with increasing strength of parental LoC. After full adjustment, children in the strongest parental LoC quintile were 2.81 (1.23–6.42, p< 0.05) times more likely to be free from untreated caries in comparison to the weakest parental LoC quintile and 2.32 (1.02–5.25, p< 0.05) times more likely to be free from caries experience in comparison to the weakest parental LoC quintile.
Conclusion:
The findings support the hypothesis that higher internal parental LoC is associated with better control of both untreated caries and caries experience in their preschool children and highlight that a more internal LoC within the family is advantageous in the prevention of dental caries
Supersymmetric QCD: Exact Results and Strong Coupling
We revisit two longstanding puzzles in supersymmetric gauge theories. The
first concerns the question of the holomorphy of the coupling, and related to
this the possible definition of an exact (NSVZ) beta function. The second
concerns instantons in pure gluodynamics, which appear to give sensible, exact
results for certain correlation functions, which nonetheless differ from those
obtained using systematic weak coupling expansions. For the first question, we
extend an earlier proposal of Arkani-Hamed and Murayama, showing that if their
regulated action is written suitably, the holomorphy of the couplings is
manifest, and it is easy to determine the renormalization scheme for which the
NSVZ formula holds. This scheme, however, is seen to be one of an infinite
class of schemes, each leading to an exact beta function; the NSVZ scheme,
while simple, is not selected by any compelling physical consideration. For the
second question, we explain why the instanton computation in the pure
supersymmetric gauge theory is not reliable, even at short distances. The
semiclassical expansion about the instanton is purely formal; if infrared
divergences appear, they spoil arguments based on holomorphy. We demonstrate
that infrared divergences do not occur in the perturbation expansion about the
instanton, but explain that there is no reason to think this captures all
contributions from the sector with unit topological charge. That one expects
additional contributions is illustrated by dilute gas corrections. These are
infrared divergent, and so difficult to define, but if non-zero give order one,
holomorphic, corrections to the leading result. Exploiting an earlier analysis
of Davies et al, we demonstrate that in the theory compactified on a circle of
radius beta, due to infrared effects, finite contributions indeed arise which
are not visible in the formal limit that beta goes to infinity.Comment: 28 pages, two references added, one typo correcte
Intravenous postoperative fluid prescriptions for children: A survey of practice
<p>Abstract</p> <p>Background</p> <p>Postoperative deaths and neurological injury have resulted from hyponatraemia associated with the use of hypotonic saline solutions following surgery. We aimed to determine the rates and types of intravenous fluids being prescribed postoperatively for children in the UK.</p> <p>Methods</p> <p>A questionnaire was sent to members of the British Association of Paediatric Surgeons (BAPS) and Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI) based at UK paediatric centres. Respondents were asked to prescribe postoperative fluids for scenarios involving children of different ages. The study period was between May 2006 and November 2006.</p> <p>Results</p> <p>The most frequently used solution was sodium chloride 0.45% with glucose 5% although one quarter of respondents still used sodium chloride 0.18% with glucose 4%. Isotonic fluids were used by 41% of anaesthetists and 9.8% of surgeons for the older child, but fewer for infants. Standard maintenance rates or greater were prescribed by over 80% of respondents.</p> <p>Conclusion</p> <p>Most doctors said they would prescribe hypotonic fluids at volumes equal to or greater than traditional maintenance rates at the time of the survey. A survey to describe practice since publication of National Patient Safety Agency (NPSA) recommendations is required.</p
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