3,969 research outputs found
A comparison of methods for treatment selection in seamless phase II/III clinical trials incorporating information on short-term endpoints
In an adaptive seamless phase II/III clinical trial interim
analysis data are used for treatment selection, enabling resources to be focussed on comparison of more effective treatment(s) with a control. In this paper we compare two methods recently proposed to enable use of short-term endpoint data for decision-making at the interim analysis. The comparison focusses on the power and the probability of correctly identifying the most promising treatment. We show that the choice of method depends on how well short-term data predict the best treatment, which may be measured by the correlation between treatment effects on short-term and long-term endpoints
Jupiter's polar ionospheric flows: measured intensity and velocity variations poleward of the main auroral oval
Recent analysis of high-resolution spectra of Doppler-shifted H3+ emission from the auroral/polar regions of Jupiter revealed a complex wind system, with a persistent auroral electrojet and strong anti-sunward flows in a region of lesser intensity centred around the magnetic pole [ Stallard et al., 2001 ]. This region, which we have called the Dark Polar Region (DPR), is re-investigated, transforming the observed line-of-sight velocities into a frame of reference fixed with respect to the magnetic pole. The DPR is shown to include a region essentially stagnant in this frame of reference (the f-DPR). We identify it as a region coupled to open magnetotail field lines. There is also a transition region in which the ion velocity returns to corotation (the r-DPR)
Multiply connected wandering domains of entire functions
The dynamical behaviour of a transcendental entire function in any periodic
component of the Fatou set is well understood. Here we study the dynamical
behaviour of a transcendental entire function in any multiply connected
wandering domain of . By introducing a certain positive harmonic
function in , related to harmonic measure, we are able to give the first
detailed description of this dynamical behaviour. Using this new technique, we
show that, for sufficiently large , the image domains contain
large annuli, , and that the union of these annuli acts as an absorbing
set for the iterates of in . Moreover, behaves like a monomial
within each of these annuli and the orbits of points in settle in the long
term at particular `levels' within the annuli, determined by the function .
We also discuss the proximity of and for large
, and the connectivity properties of the components of . These properties are deduced from new results about the behaviour
of an entire function which omits certain values in an annulus
Estimating age-status-specific demographic rates that are consistent with the projected summary measures in family households projection
This paper proposes procedures for estimating age-status-specific demographic rates to ensure that the projected summary measures of marriage/union formation and dissolution and marital and non-marital fertility in the future years are achieved consistently. The procedures proposed in this paper can be applied in both macro and micro models for family household or actuarial/welfare projections and simulations that need the time-varying age-status-specific demographic rates as input.family demography
Dynamics of meromorphic functions with direct or logarithmic singularities
We show that if a meromorphic function has a direct singularity over
infinity, then the escaping set has an unbounded component and the intersection
of the escaping set with the Julia set contains continua. This intersection has
an unbounded component if and only if the function has no Baker wandering
domains. We also give estimates of the Hausdorff dimension and the upper box
dimension of the Julia set of a meromorphic function with a logarithmic
singularity over infinity. The above theorems are deduced from more general
results concerning functions which have "direct or logarithmic tracts", but
which need not be meromorphic in the plane. These results are obtained by using
a generalization of Wiman-Valiron theory. The method is also applied to complex
differential equations.Comment: 29 pages, 2 figures; v2: some overall revision, with comments and
references added; to appear in Proc. London Math. So
Estimating time-varying sex-age-specific o/e rates of marital status transitions in family household projection or simulation
This article presents a procedure for estimating time-varying sex-age-specific occurrence/exposure (o/e) rates of marital status transitions to ensure that the projected life course propensities of marriage/union formation and dissolution are achieved consistently in the one-sex family status life table model. Procedures for estimating time-varying sex-age-specific marital status transition o/e rates that are consistent with the two-sex constraints and projected summary measures of marriage/union formation and dissolution in the future years in the two-sex family household projection model is proposed. The procedures proposed in this article are practically useful and can be applied in both macro and micro models for family household projections or simulations that need time-varying sex-age-specific o/e rates of marital status transitions.family, household, marriage, projections, simulation
Estimating time-varying sex-age-specific o/e rates of marital status transitions in family household projection or simulation
This article presents a procedure for estimating time-varying sex-age-specific occurrence/exposure (o/e) rates of marital status transitions to ensure that the projected life course propensities of marriage/union formation and dissolution are achieved consistently in the one-sex family status life table model. Procedures for estimating time-varying sex-age-specific marital status transition o/e rates that are consistent with the two-sex constraints and projected summary measures of marriage/union formation and dissolution in the future years in the two-sex family household projection model is proposed. The procedures proposed in this article are practically useful and can be applied in both macro and micro models for family household projections or simulations that need time-varying sex-age-specific o/e rates of marital status transitions.
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