2,353 research outputs found
Calculation of LTC Premiums based on direct estimates of transition probabilities
In this paper we model the life-history of LTC patients using a Markovian multi-state model in order to calculate premiums for a given LTC-plan. Instead of estimating the transition intensities in this model we use the approach suggested by Andersen et al. (2003) for a direct estimation of the transition probabilities. Based on the Aalen-Johansen estimator, an almost unbiased estimator for the transition matrix of a Markovian multi-state model, we calculate so-called pseudo-values, known from Jackknife methods. Further, we assume that the relationship between these pseudo-values and the covariates of our data are given by a GLM with the logit as link-function. Since the GLMs do not allow for correlation between successive observations we use instead the "Generalized Estimating Equations" (GEEs) to estimate the parameters of our regression model. The approach is illustrated using a representative sample from a German LTC portfolio
Lutheranism in the Region of New York Until the Time of Falckner
The history of the Lutheran Church in the region of New York has its beginning contemporaneously with the beginning of the state of New York. Already at the time of the earliest explorations of that territory and the settlement of the first Dutch colony, we find traces of Lutheranism. True, the Lutherans never were a very large force; and, as a body, they had 1ittle to do with the shaping of New York’s development; nevertheless, Lutheranism was present. There was, also a nernber of individuals of, whose secular work the Lutheran Church can well be proud.
In our discussion we shall attempt to follow the Church from its very first signs until the time of Justus Falckner, who died in 1723. Actually, we shall proceed a little further in our story until 1750 where there is a logical stopping place
Modelling spring flood in the area of the Upper Volga basin
Integrated river-basin management for the Volga river requires understanding and modelling of the flow process in its macro-scale tributary catchments. At the example of the Kostroma catchment (16 000 km<sup>2</sup>), a method combining existing hydrologic simulation tools was developed that allows operational modelling even when data are scarce. Emphasis was placed on simulation of three processes: snow cover development using a snow-compaction model, runoff generation using a conceptual approach with parameters for seasonal antecedent moisture conditions, and runoff concentration using a regionalised unit hydrograph approach. Based on this method, specific regional characteristics of the precipitation-runoff process were identified, in particular a distinct threshold behaviour of runoff generation in catchments with clay-rich soils. With a plausible overall parameterisation of involved tools, spring flood events could successfully be simulated. Present paper mainly focuses on the simulation of a 16-year sample of snowmelt events in a meso-scale catchment. An example of regionalised simulation in the scope of the modelling system "Flussgebietsmodell" shows the capabilities of developed method for application in macro-scale tributary catchments of the Upper Volga basin
Heat transfer and oil flow studies on a single-stage-to-orbit control-configured winged entry vehicle
Results are presented for oil flow and phase change paint heat transfer tests conducted on a 0.006 scale model of a proposed single stage to orbit control configured vehicle. The data were taken at angles of attack up to 40 deg at a free stream Mach number of 10 for Reynolds numbers based on model length of 0.5 x 10 to the 6th power, 1.0 x 10 to the 6th power and 2.0 x 10 to the 6th power. The magnitude and distribution of heating are characterized in terms of angle of attack and Reynolds number aided by an analysis of the flow data which are used to suggest the presence of various three dimensional flow structures that produce the observed heating patterns. Of particular interest are streak heating patterns that result in high localized heat transfer rates on the wing windward surface at low to moderate angles of attack. These streaks are caused by the bow-shock/wing-shock interaction and formation of the wing-shock. Embedded vorticity was found to be associated with these interactions
Brain tissue properties differentiate between motor and limbic basal ganglia circuits
Despite advances in understanding basic organizational principles of the human basal ganglia, accurate in vivo assessment of their anatomical properties is essential to improve early diagnosis in disorders with corticosubcortical pathology and optimize target planning in deep brain stimulation. Main goal of this study was the detailed topological characterization of limbic, associative, and motor subdivisions of the subthalamic nucleus (STN) in relation to corresponding corticosubcortical circuits. To this aim, we used magnetic resonance imaging and investigated independently anatomical connectivity via white matter tracts next to brain tissue properties. On the basis of probabilistic diffusion tractography we identified STN subregions with predominantly motor, associative, and limbic connectivity. We then computed for each of the nonoverlapping STN subregions the covariance between local brain tissue properties and the rest of the brain using high-resolution maps of magnetization transfer (MT) saturation and longitudinal (R1) and transverse relaxation rate (R2*). The demonstrated spatial distribution pattern of covariance between brain tissue properties linked to myelin (R1 and MT) and iron (R2*) content clearly segregates between motor and limbic basal ganglia circuits. We interpret the demonstrated covariance pattern as evidence for shared tissue properties within a functional circuit, which is closely linked to its function. Our findings open new possibilities for investigation of changes in the established covariance pattern aiming at accurate diagnosis of basal ganglia disorders and prediction of treatment outcom
Experimental Study of a Hot Structure for a Reentry Vehicle
A large structural model of a reentry vehicle has been built incorporating design concepts applicable to a radiation-cooled vehicle. Thermal-stress alleviating features of the model are discussed. Environmental tests on the model include approximately 100 cycles of loading at room temperature and 33 cycles of combined loading and-heating up to temperatures of 1,6000 F. Measured temperatures are shown for typical parts of the model. Comparisons are made between experimental and calculated deflections and strains. The structure successfully survived the heating and loading environments
From in situ to ex vivo: the effect of autolysis and fixation on quantitative MRI markers for myelin
Ex vivo histology remains the gold standard against which MRI biophysical models, e.g. the MR g-ratio which characterises the fraction of a fibre’s diameter that is myelinated, are evaluated. The MR g-ratio model requires a measure of myelin density, for which magnetization transfer saturation (MT) has been used as a biomarker. However, changes occurring post mortem, e.g. autolysis, temperature changes and fixation, significantly alter the MRI signal. Here we investigate how these changes impact MT. We found that MT decreased post mortem but greatlyincreased upon fixation. These effects are similar to reported changes of other established MRI myelin-markers
Integral-field spectroscopy of the quadruple QSO HE 0435-1223: Evidence for microlensing
We present the first spatially resolved spectroscopic observations of the
recently discovered quadruple QSO and gravitational lens HE0435-1223. Using the
Potsdam Multi-Aperture Spectrophotometer (PMAS), we show that all four QSO
components have very similar but not identical spectra. In particular, the
spectral slopes of components A, B, and D are indistinguishable, implying that
extinction due to dust plays no major role in the lensing galaxy. While also
the emission line profiles are identical within the error bars, as expected
from lensing, the equivalent widths show significant differences between
components. Most likely, microlensing is responsible for this phenomenon. This
is also consistent with the fact that component D, which shows the highest
relative continuum level, has brightened by 0.07 mag since Dec 2001. We find
that the emission line flux ratios between the components are in better
agreement with simple lens models than broad band or continuum measurements,
but that the discrepancies between model and data are still unacceptably large.
Finally, we present a detection of the lensing galaxy, although this is close
to the limits of the data. Comparing with a model galaxy spectrum, we obtain a
redshift estimate of z_lens=0.44+-0.02.Comment: 9 pages, 7 figures, accepted for publication in A&
- …