326 research outputs found
Effect of the boundary layer upon the flow in a conical hypersonic nozzle
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76641/1/AIAA-2269-288.pd
Eliminating Ditransitives
Abstract. We discuss how higher arity verbs such as give or promise can be treated in an algebraic framework that admits only unary and binary relations and does not rely on event variables
Nonlinear DC-response in Composites: a Percolative Study
The DC-response, namely the - and - charateristics, of a variety
of composite materials are in general found to be nonlinear. We attempt to
understand the generic nature of the response charactersistics and study the
peculiarities associated with them. Our approach is based on a simple and
minimal model bond percolative network. We do simulate the resistor network
with appropritate linear and nonlinear bonds and obtain macroscopic nonlinear
response characteristics. We discuss the associated physics. An effective
medium approximation (EMA) of the corresponding resistor network is also given.Comment: Text written in RevTEX, 15 pages (20 postscript figures included),
submitted to Phys. Rev. E. Some minor corrections made in the text, corrected
one reference, the format changed (from 32 pages preprint to 15 pages
Tracking the spatial diffusion of influenza and norovirus using telehealth data: A spatiotemporal analysis of syndromic data
Background: Telehealth systems have a large potential for informing public health authorities in
an early stage of outbreaks of communicable disease. Influenza and norovirus are common viruses
that cause significant respiratory and gastrointestinal disease worldwide. Data about these viruses
are not routinely mapped for surveillance purposes in the UK, so the spatial diffusion of national
outbreaks and epidemics is not known as such incidents occur. We aim to describe the
geographical origin and diffusion of rises in fever and vomiting calls to a national telehealth system,
and consider the usefulness of these findings for influenza and norovirus surveillance.
Methods: Data about fever calls (5- to 14-year-old age group) and vomiting calls (≥ 5-year-old age
group) in school-age children, proxies for influenza and norovirus, respectively, were extracted
from the NHS Direct national telehealth database for the period June 2005 to May 2006. The
SaTScan space-time permutation model was used to retrospectively detect statistically significant
clusters of calls on a week-by-week basis. These syndromic results were validated against existing
laboratory and clinical surveillance data.
Results: We identified two distinct periods of elevated fever calls. The first originated in the
North-West of England during November 2005 and spread in a south-east direction, the second
began in Central England during January 2006 and moved southwards. The timing, geographical
location, and age structure of these rises in fever calls were similar to a national influenza B
outbreak that occurred during winter 2005–2006. We also identified significantly elevated levels of
vomiting calls in South-East England during winter 2005–2006.
Conclusion: Spatiotemporal analyses of telehealth data, specifically fever calls, provided a timely
and unique description of the evolution of a national influenza outbreak. In a similar way the tool
may be useful for tracking norovirus, although the lack of consistent comparison data makes this
more difficult to assess. In interpreting these results, care must be taken to consider other
infectious and non-infectious causes of fever and vomiting. The scan statistic should be considered
for spatial analyses of telehealth data elsewhere and will be used to initiate prospective geographical
surveillance of influenza in England.
Low voltage electrical properties of polypropylene filled with stainless steel fibres and a model of sample conductivity based on fibre geometry
Fragmented maternal sleep is more strongly correlated with depressive symptoms than infant temperament at three months postpartum
Estimating Animal Abundance in Ground Beef Batches Assayed with Molecular Markers
Estimating animal abundance in industrial scale batches of ground meat is important for mapping meat products through the manufacturing process and for effectively tracing the finished product during a food safety recall. The processing of ground beef involves a potentially large number of animals from diverse sources in a single product batch, which produces a high heterogeneity in capture probability. In order to estimate animal abundance through DNA profiling of ground beef constituents, two parameter-based statistical models were developed for incidence data. Simulations were applied to evaluate the maximum likelihood estimate (MLE) of a joint likelihood function from multiple surveys, showing superiority in the presence of high capture heterogeneity with small sample sizes, or comparable estimation in the presence of low capture heterogeneity with a large sample size when compared to other existing models. Our model employs the full information on the pattern of the capture-recapture frequencies from multiple samples. We applied the proposed models to estimate animal abundance in six manufacturing beef batches, genotyped using 30 single nucleotide polymorphism (SNP) markers, from a large scale beef grinding facility. Results show that between 411∼1367 animals were present in six manufacturing beef batches. These estimates are informative as a reference for improving recall processes and tracing finished meat products back to source
Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy
Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86–1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91–1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable. Funding: UK Medical Research Council and Health Technology Assessment Programme
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