Exploring US Business Cycles with Bivariate Loops Using Penalized Spline Regression

The phrase business cycle is usually used for short term fluctuations in macroeconomic time series. In this paper we focus on the estimation of business cycles in a bivariate manner by fitting two series simultaneously. The underlying model is thereby nonparametric in that no functional form is prespecified but smoothness of the functions are assumed. The functions are then estimated using penalized spline estimation. The bivariate approach will allow to compare business cycles, check and compare phase lengths and visualize this in forms of loops in a bivariate way. Moreover, the focus is on separation of long and short phase fluctuation, where only the latter is the classical business cycle while the first is better known as Friedman or Goodwin cycle, respectively. Again, we use nonparametric models and fit the functional shape with penalized splines. For the separation of long and short phase components we employ an Akaike criterion.     

The effect of flooring on musculoskeletal symptoms in the lower extremities and low back among female nursing assistants

This study examines the effect of changing the floor from a 2-mm homogenous vinyl floor to a 4-mm heterogeneous vinyl floor (1.5-mm wear layer and 2.5-mm foam layer) on musculoskeletal symptoms in the lower extremities and low back among nursing assistants in a geriatric care centre. A pre-post design with a reference group consisting of nursing assistants from a similar geriatric care centre was used. Follow-up measurements were carried out 12 and 24 months after the intervention by means of questionnaires. At the 1-year follow-up, the pain intensity score in the feet of the intervention group had decreased compared with the baseline value and remained statistically significant at the 2-year follow-up. The decrease in pain intensity score of the feet in the intervention group was statistically significantly different from the reference group, both after 1 and 2 years. PRACTITIONER SUMMARY: The results show the importance of flooring in the workplace with regard to reducing musculoskeletal symptoms. Appropriate flooring is especially important in the female-dominated health care sector, where workers must stand or walk for long periods.     

Composite indicator for railway infrastructure management

Railway Engineering Science - The assessment and analysis of railway infrastructure capacity is an essential task in railway infrastructure management carried out to meet the required quality and...     

Analysing quadratic effects of formative constructs by means of variance-based structural equation modelling

Together with the development of information systems research, there has also been increased interest in non-linear relationships between focal constructs. This article presents six Partial Least Squares-based approaches for estimating formative constructs’ quadratic effects. In addition, these approaches’ performance is tested by means of a complex Monte Carlo experiment. The experiment reveals significant and substantial differences between the approaches. In general, the performance of the hybrid approach as suggested by Wold (1982) is most convincing in terms of point estimate accuracy, statistical power, and prediction accuracy. The two-stage approach suggested by Chin et al (1996) showed almost the same performance; differences between it and the hybrid approach – although statistically significant – were unsubstantial. Based on these results, the article provides guidelines for the analysis of non-linear effects by means of variance-based structural equation modelling.     

Plastic deformation of linear polyethylene containing row structures

The mechanical and thermal properties of highly oriented polyethylene films containing shish kebab type morphology are studied. At low deformations (strain<10%) strong work hardening is observed. Higher deformations ((40%) give rise to strain softening of the material and a decrease in the Young's modulus of as much as one-third of its initial value. In addition, the high melting component of the material originating from the shish-type crystals vanishes on higher deformation. The deformation processes are discussed from the point of view of a fibre-composite material and structural changes during the deformation are followed by transmission electron microscopy.     

On the prediction of band-limited signals from past samples

A new method is used to construct coefficients a_kn such that any band-limited signal function with highest frequency ΠW can be reconstituted from its samples from the past via

$\text{?(t)=}\text{lim}\text{n→∞}\text{σ}\text{k=1}\text{n}\text{a}{}_{\mathrm{kn}}\text{?}\text{t?}\text{kT}\text{W}$

Although the existence of such predictor coefficients can be proved for each positive T < 1, so far they have been exhibited only for $\text{T ? (0,}\text{built1}\text{2}\text{)}$ by J. L. Brown, Jr. [1]. Using the mathematical tool of power series expansions in the complex domain, T can be extended to at least $\text{T <}\text{1}\text{2}$, that is, the sampling rate has to exceed three-halves the Nyquist rate. Again the predictor coefficients a_kn do not depend on the structure of ? or on the bandwidth parameter W.     

Influence of disordering by low-temperature neutron irradiation on the superconducting transition temperature of Nb3Sn

The superconducting transition temperatureT _c of a Nb₃Sn diffusion wire has been studied as a function of low-temperature neutron irradiation (T=10 K).T _c is observed to be essentially constant until the fast neutron dose t (for neutron energiesE>0.1 MeV) exceeds a value of 10¹⁸ n/cm²; after this valueT _c decreases linearly with t up to the maximum applied dose of 1.05×10¹⁹ n/cm². Comparison with theory and other experimental data indicates that radiation-induced disorder is the primary mechanism for the observedT _c changes.Work supported by the Bundesministerium für Forschung und Technologie and by the Deutsche Forschungsgemeinschaft.     

Calculations of the Elastic Scattering Properties of Ultra-cold Francium Isotopes

The calculations of the elastic scattering properties of ultra-cold francium isotopes are reported in detail. A parametric model potential for the triplet molecular states of the Fr₂ is represented, and the scattering lengths a_t and the effective range r_e are calculated using WKB and Numerov methods for Fr--Fr in the triplet state. The convergence of these scattering properties depending on a K⁰ parameter and core radius is also investigated using two methods: Quantum Defect Theory and analytical formula of Symskoviski.     

Coordination in networks: An economic equilibrium analysis

Networks utilizing modern communication technologies can offer competitive advantages to those using them wisely. But due to the existence of network effects, planning and operating cooperation networks is difficult. In this paper, the strategic situation of individual agents deciding on network participation is analysed. A systematic equilibrium analysis using computer-based simulations reveals principal solution scenarios for network agents and shows that network cooperation problems might frequently be not as difficult to resolve as often feared. In particular, strategic situations are identified showing that a majority of individuals might be better off getting the optimal solution from a central principal and that in many cases simple information intermediation can solve the start-up problem notorious in network economics.     

High Order Finite Difference Approximations of Electromagnetic Wave Propagation Close to Material Discontinuities

Electromagnetic wave propagation close to a material discontinuity is simulated by using summation by part operators of second, fourth and sixth order accuracy. The interface conditions at the discontinuity are imposed by the simultaneous approximation term procedure. Stability is shown and the order of accuracy is verified numerically.