The Evolution of High Incomes in Canada, 1920-2000

This paper presents new homogeneous series on top shares of income from 1920 to 2000 in Canada using personal income tax return data. Top income shares display a U-shaped pattern over the century, with a precipitous drop during World War II, followed by a slower decline until 1970. Since the late 1970s, top income shares have been increasing steadily and the very top shares are now as high as in the pre-war era. As in the United States, the recent increase in top income shares is the consequence of a surge in top wages and salaries. The parallel evolution of top income shares in Canada and the United States, associated with much more modest marginal tax rate cuts in Canada, suggests that the upward trend in top shares in Canada since the late 1970s cannot be explained by tax cuts. Further evidence suggests that the upward trend in Canada derives from the United States, perhaps because many Canadians have an emigration option.income share

The Evolution of High Incomes in Canada, 1920-2000

This paper presents new homogeneous series on top shares of income from 1920 to 2000 in Canada using personal income tax return data. Top income shares display a U-shaped pattern over the century, with a precipitous drop during World War II, followed by a slower decline until 1970. Since the late 1970s, top income shares have been increasing steadily and the very top shares are now as high as in the pre-war era. As in the United States, the recent increase in top income shares is the consequence of a surge in top wages and salaries. As a result, series on the composition of incomes within the top income groups from 1946 to 2000 show a dramatic increase in the share of wages and salaries. The parallel evolution of top income shares in Canada and the United States, associated with much more modest marginal tax rate cuts in Canada, suggests that the upward trend in top shares in Canada since the late 1970s cannot be explained by tax cuts. Further evidence suggests that the upward trend in Canada derives from the United States, perhaps because many Canadians have an emigration option. A data appendix for this paper is available.

The Evolution of High Incomes in Canada, 1920-2000

This paper presents new homogeneous series on top shares of income from 1920 to 2000 in Canada using personal income tax return data. Top income shares display a U-shaped pattern over the century, with a precipitous drop during World War II, followed by a slower decline until 1970. Since the late 1970s, top income shares have been increasing steadily and the very top shares are now as high as in the pre-war era. As in the United States, the recent increase in top income shares is the consequence of a surge in top wages and salaries. The parallel evolution of top income shares in Canada and the United States, associated with much more modest marginal tax rate cuts in Canada, suggests that the upward trend in top shares in Canada since the late 1970s cannot be explained by tax cuts. Further evidence suggests that the upward trend in Canada derives from the United States, perhaps because many Canadians have an emigration option.income share

Self similar expanding solutions of the planar network flow

We prove the existence of self-similar expanding solutions of the curvature flow on planar networks where the initial configuration is any number of half-lines meeting at the origin. This generalizes recent work by Schn\"urer and Schulze which treats the case of three half-lines. There are multiple solutions, and these are parametrized by combinatorial objects, namely Steiner trees with respect to a complete negatively curved metric on the unit ball which span $k$ specified points on the boundary at infinity. We also provide a sharp formulation of the regularity of these solutions at $t=0$

Importance of tetrahedral coordination for high-valent transition metal oxides: YCrO4_4 as a model system

We have investigated the electronic structure of the high oxidation state material YCrO$_4$ within the framework of the Zaanen-Sawatzky-Allen phase diagram. While Cr$^{4+}$-based compounds like SrCrO$_3$/CaCrO$_3$ and CrO$_2$ can be classified as small-gap or metallic negative-charge-transfer systems, we find using photoelectron spectroscopy that YCrO$_4$ is a robust insulator despite the fact that its Cr ions have an even higher formal valence state of 5+. We reveal using band structure calculations that the tetrahedral coordination of the Cr$^{5+}$ ions in YCrO$_4$ plays a decisive role, namely to diminish the bonding of the Cr $3d$ states with the top of the O $2p$ valence band. This finding not only explains why the charge-transfer energy remains effectively positive and the material stable, but also opens up a new route to create doped carriers with symmetries different from those of other transition-metal ions.Comment: 6 pages, 6 figure

RF Power Amplifier Linearization in Professional Mobile Radio Communications Using Artificial Neural Networks

This paper is focused on the linearization of the radio frequency power amplifier of a professional digital handheld by means of an artificial neural network. The simplicity of the neural network that is used, together with the fact that a feedback path is unnecessary, makes this solution ideal to reduce both the cost of a handheld and its hardware complexity, while fully maintaining its performance. A compensation system is also needed to keep the linearization characteristics of the neural network stable against frequency, temperature, and voltage variations. The whole solution that comprises both the neural network and the compensation system has been implemented in the digital signal processor of a real handheld and afterward fully tested. It has proved to be satisfactory to meet the telecommunication standard requirements in all frequency, temperature, and voltage ranges under consideration while efficient to lower the computational cost of the handheld and to make its internal hardware simpler in comparison with other traditional linearization techniques. The results obtained demonstrate that a neural network can be used to linearize the power amplifiers that are used in transmitters of telecommunication equipment, leading to a significant reduction of both their hardware cost and complexity

Investigating the mechanisms underlying fixation durations during the first year of life: a computational account

Infants’ eye-movements provide a window onto the development of cognitive functions over the first years of life. Despite considerable advances in the past decade, studying the mechanisms underlying infant fixation duration and saccadic control remains a challenge due to practical and technical constraints in infant testing. This thesis addresses these issues and investigates infant oculomotor control by presenting novel software and methods for dealing with low-quality infant data (GraFIX), a series of behavioural studies involving novel gaze-contingent and sceneviewing paradigms, and computational modelling of fixation timing throughout development. In a cross-sectional study and two longitudinal studies, participants were eye-tracked while viewing dynamic and static complex scenes, and performed gap-overlap and double-step paradigms. Fixation data from these studies were modelled in a number of simulation studies with the CRISP model of fixation durations in adults in scene viewing. Empirical results showed how fixation durations decreased with age for all viewing conditions but at different rates. Individual differences between long- and short-lookers were found across visits and viewing conditions, with static images being the most stable viewing condition. Modelling results confirmed the CRISP theoretical framework’s applicability to infant data and highlighted the influence of both cognitive processing and the developmental state of the visuo-motor system on fixation durations during the first few months of life. More specifically, while the present work suggests that infant fixation durations reflect on-line perceptual and cognitive activity similarly to adults, the individual developmental state of the visuo-motor system still affects this relationship until 10 months of age. Furthermore, results suggested that infants are already able to program saccades in two stages at 3.5 months: (1) an initial labile stage subject to cancellation and (2) a subsequent non-labile stage that cannot be cancelled. The length of the non-labile stage decreased relative to the labile stage especially from 3.5 to 5 months, indicating a greater ability to cancel saccade programs as infants grew older. In summary, the present work provides unprecedented insights into the development of fixation durations and saccadic control during the first year of life and demonstrates the benefits of mixing behavioural and computational approaches to investigate methodologically challenging research topics such as oculomotor control in infancy