1,023,916 research outputs found
Does Modern Econometrics replicate the Phillips Curve?
This paper reexamines the existence of a long-run relationship between wages and unemployment in the U.K., with data over the period 1860-1913 used by A.W. Phillips to derive the well-known Phillips Curve. Using Johansen's maximum likelihood method of testing for cointegration, a long-run inverse relationship is indeed depicted between the rate of inflation and the unemployment rate. However, the main impact of deviations from this long-run equilibrium is on the unemployment rate rather than the rate of inflation.Phillips Curve; long-run equilibrium; cointegration
Age and interhemispheric transfer time: A failure to replicate.
In a recent study with the Poffenberger paradigm, Brizzolara et al. reported longer estimates of interhemispheric transfer time (IHTT) for children aged 7 years than for adults. They interpreted this finding as evidence for incomplete functional maturity of the corpus callosum in young children. The present study was we were unable to replicate the age effect reported by Brizzolara et al. A closer look at the original study revealed that only 80 observations per child had been collected, which makes it probable that the larger IHTTs in 7-year-olds were caused by stimulus-response compatibility rather than by the lower efficiency of the corpus callosum during childhood years
Replicate Periodic Windows in the Parameter Space of Driven Oscillators
In the bi-dimensional parameter space of driven oscillators, shrimp-shaped
periodic windows are immersed in chaotic regions. For two of these oscillators,
namely, Duffing and Josephson junction, we show that a weak harmonic
perturbation replicates these periodic windows giving rise to parameter regions
correspondent to periodic orbits. The new windows are composed of parameters
whose periodic orbits have periodicity and pattern similar to stable and
unstable periodic orbits already existent for the unperturbed oscillator. These
features indicate that the reported replicate periodic windows are associated
with chaos control of the considered oscillators
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(Non)Parallel Evolution
Parallel evolution across replicate populations has provided evolutionary biologists with iconic examples of adaptation. When multiple populations colonize seemingly similar habitats, they may evolve similar genes, traits, or functions. Yet, replicated evolution in nature or in the laboratory often yields inconsistent outcomes: Some replicate populations evolve along highly similar trajectories, whereas other replicate populations evolve to different extents or in distinct directions. To understand these heterogeneous outcomes, biologists are increasingly treating parallel evolution not as a binary phenomenon but rather as a quantitative continuum ranging from parallel to nonparallel. By measuring replicate populations’ positions along this (non)parallel continuum, we can test hypotheses about evolutionary and ecological factors that influence the extent of repeatable evolution. We review evidence regarding the manifestation of (non)parallel evolution in the laboratory, in natural populations, and in applied contexts such as cancer. We enumerate the many genetic, ecological, and evolutionary processes that contribute to variation in the extent of parallel evolution
The elusive nature of the blocking effect: 15 failures to replicate
With the discovery of the blocking effect, learning theory took a huge leap forward, because blocking provided a crucial clue that surprise is what drives learning. This in turn stimulated the development of novel association-formation theories of learning. Eventually, the ability to explain blocking became nothing short of a touchstone for the validity of any theory of learning, including propositional and other nonassociative theories. The abundance of publications reporting a blocking effect and the importance attributed to it suggest that it is a robust phenomenon. Yet, in the current article we report 15 failures to observe a blocking effect despite the use of procedures that are highly similar or identical to those used in published studies. Those failures raise doubts regarding the canonical nature of the blocking effect and call for a reevaluation of the central status of blocking in theories of learning. They may also illustrate how publication bias influences our perspective toward the robustness and reliability of seemingly established effects in the psychological literature
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