19,689 research outputs found
Perspectives in Ornithology: Application of tracking and data-logging technology in research and conservation of seabirds
Monetary expansion and federal open market committee operating strategy in 1971
Federal Open Market Committee ; Monetary policy - United States
Seasonality, precautionary savings and health uncertainty: Evidence from farm households in central Kenya
The high prevalence of risks in low income economies makes managing uncertainty critical for productivity and survival. This paper analyzes seasonal changes in farm households’ per capita consumption and saving in response to weather and health shocks. Using a sample of 196 households in central Kenya, it tests the notion that people save most of their transitory income, and examines their precautionary saving motives. The results show that the propensity to save out of transitory income is about a fifth of what the permanent income hypothesis postulates. The propensity to save differs by wealth, with the poor exhibiting stronger precautionary motives towards rainfall variability. But the wealth effect is weak, suggesting that the asset base is vulnerable even for the better-off. However, precautionary savings tend to increase with wealth among HIV/AIDS affected households. Since illness is associated with higher consumption, and therefore less investment, we find more volatile consumption for HIV/AIDS affected households
A Rigorous Finite-Element Domain Decomposition Method for Electromagnetic Near Field Simulations
Rigorous computer simulations of propagating electromagnetic fields have
become an important tool for optical metrology and design of nanostructured
optical components. A vectorial finite element method (FEM) is a good choice
for an accurate modeling of complicated geometrical features. However, from a
numerical point of view solving the arising system of linear equations is very
demanding even for medium sized 3D domains. In numerics, a domain decomposition
method is a commonly used strategy to overcome this problem. Within this
approach the overall computational domain is split up into smaller domains and
interface conditions are used to assure continuity of the electromagnetic
field. Unfortunately, standard implementations of the domain decomposition
method as developed for electrostatic problems are not appropriate for wave
propagation problems. In an earlier paper we therefore proposed a domain
decomposition method adapted to electromagnetic field wave propagation
problems. In this paper we apply this method to 3D mask simulation.Comment: 9 pages, 7 figures, SPIE conference Advanced Lithography / Optical
Microlithography XXI (2008
Flexible nurse staffing based on hourly bed census predictions
Workload on nursing wards depends highly on patient arrivals and patient lengths of stay, which are both inherently variable. Predicting this workload and staffing nurses accordingly is essential for guaranteeing quality of care in a cost effective manner. This paper introduces a stochastic method that uses hourly census predictions to derive efficient nurse staffing policies. The generic analytic approach minimizes staffing levels while satisfying so-called nurse-to-patient ratios. In particular, we explore the potential of flexible staffing policies which allow hospitals to dynamically respond to their fluctuating patient population by employing float nurses. The method is applied to a case study of the surgical inpatient clinic of the Academic Medical Center (AMC) Amsterdam. This case study demonstrates the method's potential to study the complex interaction between staffing requirements and several interrelated planning issues such as case mix, care unit partitioning and size, and surgical block planning. Inspired by the numerical results, the AMC decided that this flexible nurse staffing methodology will be incorporated in the redesign of the inpatient care operations during the upcoming years
Notes on drift theory
It is shown that there is a simpler way to derive the average guiding center drift of a distribution of particles than via the so-called single particle analysis. Based on this derivation it is shown that the entire drift formalism can be considerably simplified, and that results for low order anisotropies are more generally valid than is usually appreciated. This drift analysis leads to a natural alternative derivation of the drift velocity along a neutral sheet
JCMmode: An Adaptive Finite Element Solver for the Computation of Leaky Modes
We present our simulation tool JCMmode for calculating propagating modes of
an optical waveguide. As ansatz functions we use higher order, vectorial
elements (Nedelec elements, edge elements). Further we construct transparent
boundary conditions to deal with leaky modes even for problems with
inhomogeneous exterior domains as for integrated hollow core Arrow waveguides.
We have implemented an error estimator which steers the adaptive mesh
refinement. This allows the precise computation of singularities near the
metal's corner of a Plasmon-Polariton waveguide even for irregular shaped metal
films on a standard personal computer.Comment: 11 page
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