Redesigning the Scajaquada Expressway

The Scajaquada Expressway was constructed in the early 1960’s and is now at the end of its functional life. The redesign and rebuilding of the roadway offers the opportunity to make it less dangerous and more compatible with the natural, historic, and cultural fabric of the parks, parkways, neighborhoods, schools, colleges, and museums it serves and impacts

VCU Symphony

VCU SymphonyDaniel Myssyk, conductorJustin Alexander, percussionFriday, October 11, 2019, at 8pmSonia Vlahcevic Concert HallW.E. Singleton Center for the Performing ArtsVirginia Commonwealth UniversityRichmond, Va

The Compulsive Gambler Process

In the compulsive gambler process there is a finite set of agents who meet pairwise at random times ($i$ and $j$ meet at times of a rate-$\nu_{ij}$ Poisson process) and, upon meeting, play an instantaneous fair game in which one wins the other's money. We introduce this process and describe some of its basic properties. Some properties are rather obvious (martingale structure; comparison with Kingman coalescent) while others are more subtle (an "exchangeable over the money elements" property, and a construction reminiscent of the Donnelly-Kurtz look-down construction). Several directions for possible future research are described. One -- where agents meet neighbors in a sparse graph -- is studied here, and another -- a continuous-space extension called the {\em metric coalescent} -- is studied in Lanoue (2014)

Discrete structure of the brain rhythms

Neuronal activity in the brain generates synchronous oscillations of the Local Field Potential (LFP). The traditional analyses of the LFPs are based on decomposing the signal into simpler components, such as sinusoidal harmonics. However, a common drawback of such methods is that the decomposition primitives are usually presumed from the onset, which may bias our understanding of the signal's structure. Here, we introduce an alternative approach that allows an impartial, high resolution, hands-off decomposition of the brain waves into a small number of discrete, frequency-modulated oscillatory processes, which we call oscillons. In particular, we demonstrate that mouse hippocampal LFP contain a single oscillon that occupies the $\theta$-frequency band and a couple of $\gamma$-oscillons that correspond, respectively, to slow and fast $\gamma$-waves. Since the oscillons were identified empirically, they may represent the actual, physical structure of synchronous oscillations in neuronal ensembles, whereas Fourier-defined "brain waves" are nothing but poorly resolved oscillons.Comment: 17 pages, 9 figure

Nature of stochastic ion heating in the solar wind: testing the dependence on plasma beta and turbulence amplitude

The solar wind undergoes significant heating as it propagates away from the Sun; the exact mechanisms responsible for this heating are not yet fully understood. We present for the first time a statistical test for one of the proposed mechanisms, stochastic ion heating. We use the amplitude of magnetic field fluctuations near the proton gyroscale as a proxy for the ratio of gyroscale velocity fluctuations to perpendicular (with respect to the magnetic field) proton thermal speed, defined as $\epsilon_p$. Enhanced proton temperatures are observed when $\epsilon_p$ is larger than a critical value ($\sim 0.019 - 0.025$). This enhancement strongly depends on the proton plasma beta ($\beta_{||p}$); when $\beta_{||p} \ll 1$ only the perpendicular proton temperature $T_{\perp}$ increases, while for $\beta_{||p} \sim 1$ increased parallel and perpendicular proton temperatures are both observed. For $\epsilon_p$ smaller than the critical value and $\beta_{||p} \ll 1$ no enhancement of $T_p$ is observed while for $\beta_{||p} \sim 1$ minor increases in $T_{\parallel}$ are measured. The observed change of proton temperatures across a critical threshold for velocity fluctuations is in agreement with the stochastic ion heating model of Chandran et al. (2010). We find that $\epsilon_p > \epsilon_{\rm crit}$ in 76\% of the studied periods implying that stochastic heating may operate most of the time in the solar wind at 1 AU.Comment: Accepted for publication in The Astrophysical Journal Letter

Subjective Well-Being, Income, Economic Development and Growth

We explore the relationships between subjective well-being and income, as seen across individuals within a given country, between countries in a given year, and as a country grows through time. We show that richer individuals in a given country are more satisfied with their lives than are poorer individuals, and establish that this relationship is similar in most countries around the world. Turning to the relationship between countries, we show that average life satisfaction is higher in countries with greater GDP per capita. The magnitude of the satisfaction-income gradient is roughly the same whether we compare individuals or countries, suggesting that absolute income plays an important role in influencing well-being. Finally, studying changes in satisfaction over time, we find that as countries experience economic growth, their citizens’ life satisfaction typically grows, and that those countries experiencing more rapid economic growth also tend to experience more rapid growth in life satisfaction. These results together suggest that measured subjective well-being grows hand in hand with material living standards.subjective well-being, life satisfaction, quality of life, economic growth, development, Easterlin Paradox, well-being-income gradient, hedonic treadmill

Subjective well-being, income, economic development and growth

We explore the relationships between subjective well-being and income, as seen across individuals within a given country, between countries in a given year, and as a country grows through time. We show that richer individuals in a given country are more satisfied with their lives than are poorer individuals, and establish that this relationship is similar in most countries around the world. Turning to the relationship between countries, we show that average life satisfaction is higher in countries with greater GDP per capita. The magnitude of the satisfaction-income gradient is roughly the same whether we compare individuals or countries, suggesting that absolute income plays an important role in influencing well-being. Finally, studying changes in satisfaction over time, we find that as countries experience economic growth, their citizens‘ life satisfaction typically grows, and that those countries experiencing more rapid economic growth also tend to experience more rapid growth in life satisfaction. These results together suggest that measured subjective well-being grows hand in hand with material living standards.Well-being - Economic aspects