16,868 research outputs found
Cost effectiveness analysis of different approaches of screening for familial hypercholesterolaemia
Objectives To assess the cost effectiveness of
strategies to screen for and treat familial
hypercholesterolaemia.
Design Cost effectiveness analysis. A care pathway for
each patient was delineated and the associated
probabilities, benefits, and costs were calculated.
Participants Simulated population aged 16Â54 years
in England and Wales.
Interventions Identification and treatment of patients
with familial hypercholesterolaemia by universal
screening, opportunistic screening in primary care,
screening of people admitted to hospital with
premature myocardial infarction, or tracing family
members of affected patients.
Main outcome measure Cost effectiveness calculated
as cost per life year gained (extension of life
expectancy resulting from intervention) including
estimated costs of screening and treatment.
Results Tracing of family members was the most cost
effective strategy (£3097 (&5066, $4479) per life year
gained) as 2.6 individuals need to be screened to
identify one case at a cost of £133 per case detected. If
the genetic mutation was known within the family
then the cost per life year gained (£4914) was only
slightly increased by genetic confirmation of the
diagnosis. Universal population screening was least
cost effective (£13 029 per life year gained) as 1365
individuals need to be screened at a cost of £9754 per
case detected. For each strategy it was more cost
effective to screen younger people and women.
Targeted strategies were more expensive per person
screened, but the cost per case detected was lower.
Population screening of 16 year olds only was as cost
effective as family tracing (£2777 with a clinical
confirmation).
Conclusions Screening family members of people
with familial hypercholesterolaemia is the most cost
effective option for detecting cases across the whole
population
Stability analysis of the Witten black hole (cigar soliton) under world-sheet RG flow
We analyze the stability of the Euclidean Witten black hole (the cigar
soliton in mathematics literature) under first-order RG (Ricci) flow of the
world-sheet sigma model. This analysis is from the target space point of view.
We find that the Witten black hole has no unstable normalizable perturbative
modes in a linearized mode analysis in which we consider circularly symmetric
perturbations. Finally, we discuss a result from mathematics that implies the
existence of a non-normalizable mode of the Witten black hole under which the
geometry flows to the sausage solution studied by Fateev, Onofri and
Zamolodchikov.Comment: 17 pages, version to appear in Physical Review D, and now has
complete proof of stability for circularly symmetric perturbations, in
response to referee comment
Preliminary flight evaluation of an engine performance optimization algorithm
A performance seeking control (PSC) algorithm has undergone initial flight test evaluation in subsonic operation of a PW 1128 engined F-15. This algorithm is designed to optimize the quasi-steady performance of an engine for three primary modes: (1) minimum fuel consumption; (2) minimum fan turbine inlet temperature (FTIT); and (3) maximum thrust. The flight test results have verified a thrust specific fuel consumption reduction of 1 pct., up to 100 R decreases in FTIT, and increases of as much as 12 pct. in maximum thrust. PSC technology promises to be of value in next generation tactical and transport aircraft
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Cno Abundances Of Hydrogen-Deficient Carbon And R Coronae Borealis Stars: A View Of The Nucleosynthesis In A White Dwarf Merger
We present high-resolution (R similar to 50,000) observations of near-IR transitions of CO and CN of the five known hydrogen-deficient carbon (HdC) stars and four R Coronae Borealis (RCB) stars. We perform an abundance analysis of these stars by using spectrum synthesis and state-of-the-art MARCS model atmospheres for cool hydrogen-deficient stars. Our analysis confirms reports by Clayton and colleagues that those HdC stars exhibiting CO lines in their spectrum and the cool RCB star SAps are strongly enriched in (18)O(with (16)O/(18)Oratios ranging from 0.3 to 16). Nitrogen and carbon are in the form of (14)N and (12)C, respectively. Elemental abundances for CNO are obtained from C I, Ci2, CN, and CO lines. Difficulties in deriving the carbon abundance are discussed. Abundances of Na from Na I lines and S from S I lines are obtained. Elemental and isotopic CNO abundances suggest that HdC and RCB stars may be related objects, and that they probably formed from a merger of an He white dwarf with a C-O white dwarf.Robert A. Welch Foundation of Houston, TexasSwedish Research CouncilGS-2006A-C-13GS-2007A-DD-1McDonald Observator
One step multiderivative methods for first order ordinary differential equations
A family of one-step multiderivative methods based on Padé approximants to the exponential function is developed.
The methods are extrapolated and analysed for use in PECE mode.
Error constants and stability intervals are calculated and the combinations compared with well known linear multi-step combinations and combinations using high accuracy Newton-Cotes quadrature formulas as correctors.
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Ultraviolet spectroscopy of old novae and symbiotic stars
The IUE spectra are presented for two old novae and for two of the symbiotic variables. Prominent emission line spectra are revealed as a continuum whose appearance is effected by the system inclination. These data provide evidence for hot companions in the symbiotic stars, making plausible the binary model for these peculiar stars. Recent IUE spectra of dwarf novae provide additional support for the existence of optically thick accretion disks in active binary systems. The ultraviolet data of the eclipsing dwarf novae EX Hya and BV Cen appear flatter than for the noneclipsing systems, an effect which could be ascribed to the system inclination
Deconstructing graviphoton from mass-deformed ABJM
Mass-deformed ABJM theory has a maximally supersymmetric fuzzy two-sphere
vacuum solution where the scalar fields are proportional to the TGRVV matrices.
We construct these matrices using Schwinger oscillators. This shows that the
ABJM gauge group that corresponds to the fuzzy two-sphere geometry is
. We deconstruct the graviphoton term in the D4 brane
theory. The normalization of this term is fixed by topological reasons. This
gives us the correct normalization of the deconstructed U(1) gauge field and
fixes the Yang -Mills coupling constant to the value which corresponds to M5
brane compactified on \mb{R}^ {1,2} \times S^3/{\mb{Z}_k}. The graviphoton
term also enable us to show that the zero mode contributions to the partition
functions for the D4 and the M5 brane agree.Comment: 26 page
On the Approximation Performance of Fictitious Play in Finite Games
We study the performance of Fictitious Play, when used as a heuristic for
finding an approximate Nash equilibrium of a 2-player game. We exhibit a class
of 2-player games having payoffs in the range [0,1] that show that Fictitious
Play fails to find a solution having an additive approximation guarantee
significantly better than 1/2. Our construction shows that for n times n games,
in the worst case both players may perpetually have mixed strategies whose
payoffs fall short of the best response by an additive quantity 1/2 -
O(1/n^(1-delta)) for arbitrarily small delta. We also show an essentially
matching upper bound of 1/2 - O(1/n)
Industrial Hemp Production and Market Risk Analysis in Oklahoma
Industrial hemp production has garnered producer attention as a potential summer crop alternative in Oklahoma. Farmers considering the inclusion of hemp, an emerging new crop, in their operations need to factor in risk and uncertainty. We conducted a risk analysis to determine the optimal allocation of land to conventional crops and hemp for a representative 1,000-acre wheat farm in northeastern Oklahoma under production and market risk. Target MOTAD (minimization of total absolute deviation) model was used to focus on downside risk and hemp market price uncertainty. Six double-cropping systems for double- cropped winter wheat were considered, including sorghum, sesame, hemp for grain, hemp for fiber, hemp for dual grain and fiber, and hemp for floral materials. Less than 4% of the 1,000-acre available land allocated to hemp for floral material and as much as 800 acres of hemp for grain and hemp for dual grain and fiber, were profit- maximizing allocations depending on the producer’s tolerance for downside risk, target profit levels, control of cross-pollination, and market conditions
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